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imagine a police lineup where ten witnesses are asked to identify a bank robber they glimpsed fleeing the crime scene . if six of them pick out the same person , there 's a good chance that 's the real culprit , and if all ten make the same choice , you might think the case is rock solid , but you 'd be wrong . for most of us , this sounds pretty strange . after all , much of our society relies on majority vote and consensus , whether it 's politics , business , or entertainment . so it 's natural to think that more consensus is a good thing . and up until a certain point , it usually is . but sometimes , the closer you start to get to total agreement , the less reliable the result becomes . this is called the paradox of unanimity . the key to understanding this apparent paradox is in considering the overall level of uncertainty involved in the type of situation you 're dealing with . if we asked witnesses to identify the apple in this lineup , for example , we should n't be surprised by a unanimous verdict . but in cases where we have reason to expect some natural variance , we should also expect varied distribution . if you toss a coin one hundred times , you would expect to get heads somewhere around 50 % of the time . but if your results started to approach 100 % heads , you 'd suspect that something was wrong , not with your individual flips , but with the coin itself . of course , suspect identifications are n't as random as coin tosses , but they 're not as clear cut as telling apples from bananas , either . in fact , a 1994 study found that up to 48 % of witnesses tend to pick the wrong person out of a lineup , even when many are confident in their choice . memory based on short glimpses can be unreliable , and we often overestimate our own accuracy . knowing all this , a unanimous identification starts to seem less like certain guilt , and more like a systemic error , or bias in the lineup . and systemic errors do n't just appear in matters of human judgement . from 1993-2008 , the same female dna was found in multiple crime scenes around europe , incriminating an elusive killer dubbed the phantom of heilbronn . but the dna evidence was so consistent precisely because it was wrong . it turned out that the cotton swabs used to collect the dna samples had all been accidentally contaminated by a woman working in the swab factory . in other cases , systematic errors arise through deliberate fraud , like the presidential referendum held by saddam hussein in 2002 , which claimed a turnout of 100 % of voters with all 100 % supposedly voting in favor of another seven-year term . when you look at it this way , the paradox of unanimity is n't actually all that paradoxical . unanimous agreement is still theoretically ideal , especially in cases when you 'd expect very low odds of variability and uncertainty , but in practice , achieving it in situations where perfect agreement is highly unlikely should tell us that there 's probably some hidden factor affecting the system . although we may strive for harmony and consensus , in many situations , error and disagreement should be naturally expected . and if a perfect result seems too good to be true , it probably is .
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but in cases where we have reason to expect some natural variance , we should also expect varied distribution . if you toss a coin one hundred times , you would expect to get heads somewhere around 50 % of the time . but if your results started to approach 100 % heads , you 'd suspect that something was wrong , not with your individual flips , but with the coin itself .
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you toss a coin 20 times and every time it turns up heads . it could be your lucky day , but then maybe not . brainstorm as many possible crazy scenarios that could have led to 20 heads in a row . which is the least likely scenario ?
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what do fans of atmospheric post-punk music have in common with ancient barbarians ? not much . so why are both known as goths ? is it a weird coincidence or a deeper connection stretching across the centuries ? the story begins in ancient rome . as the roman empire expanded , it faced raids and invasions from the semi-nomadic populations along its borders . among the most powerful were a germanic people known as goths who were composed of two tribal groups , the visigoths and ostrogoths . while some of the germanic tribes remained rome 's enemies , the empire incorporated others into the imperial army . as the roman empire split in two , these tribal armies played larger roles in its defense and internal power struggles . in the 5th century , a mercenary revolt lead by a soldier named odoacer captured rome and deposed the western emperor . odoacer and his ostrogoth successor theoderic technically remained under the eastern emperor 's authority and maintained roman traditions . but the western empire would never be united again . its dominions fragmented into kingdoms ruled by goths and other germanic tribes who assimilated into local cultures , though many of their names still mark the map . this was the end of the classical period and the beginning of what many call the dark ages . although roman culture was never fully lost , its influence declined and new art styles arose focused on religious symbolism and allegory rather than proportion and realism . this shift extended to architecture with the construction of the abbey of saint denis in france in 1137 . pointed arches , flying buttresses , and large windows made the structure more skeletal and ornate . that emphasized its open , luminous interior rather than the sturdy walls and columns of classical buildings . over the next few centuries , this became a model for cathedrals throughout europe . but fashions change . with the italian renaissance 's renewed admiration for ancient greece and rome , the more recent style began to seem crude and inferior in comparison . writing in his 1550 book , `` lives of the artists , '' giorgio vasari was the first to describe it as gothic , a derogatory reference to the barbarians thought to have destroyed classical civilization . the name stuck , and soon came to describe the medieval period overall , with its associations of darkness , superstition , and simplicity . but time marched on , as did what was considered fashionable . in the 1700s , a period called the enlightenment came about , which valued scientific reason above all else . reacting against that , romantic authors like goethe and byron sought idealized visions of a past of natural landscapes and mysterious spiritual forces . here , the word gothic was repurposed again to describe a literary genre that emerged as a darker strain of romanticism . the term was first applied by horace walpole to his own 1764 novel , `` the castle of otranto '' as a reference to the plot and general atmosphere . many of the novel 's elements became genre staples inspiring classics and the countless movies they spawned . the gothic label belonged to literature and film until the 1970s when a new musical scene emerged . taking cues from artists like the doors and the velvet underground , british post-punk groups , like joy division , bauhaus , and the cure , combined gloomy lyrics and punk dissonance with imagery inspired by the victorian era , classic horror , and androgynous glam fashion . by the early 1980s , similar bands were consistently described as gothic rock by the music press , and the stye 's popularity brought it out of dimly lit clubs to major labels and mtv . and today , despite occasional negative media attention and stereotypes , gothic music and fashion continue as a strong underground phenomenon . they 've also branched into sub-genres , such as cybergoth , gothabilly , gothic metal , and even steampunk . the history of the word gothic is embedded in thousands of years worth of countercultural movements , from invading outsiders becoming kings to towering spires replacing solid columns to artists finding beauty in darkness . each step has seen a revolution of sorts and a tendency for civilization to reach into its past to reshape its present .
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although roman culture was never fully lost , its influence declined and new art styles arose focused on religious symbolism and allegory rather than proportion and realism . this shift extended to architecture with the construction of the abbey of saint denis in france in 1137 . pointed arches , flying buttresses , and large windows made the structure more skeletal and ornate .
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why did renaissance thinkers consider medieval architecture barbaric ?
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sugar is playing hide and seek with you . you 'd think it would be pretty easy for you to win , considering all the sugar in sodas , ice cream , candy , and big white bags labeled sugar . people get about half of their added sugars from those drinks and treats , so it might seem like sugar is hiding in plain sight , but like someone in the witness protection program , the other half is hidden in places you 'd least suspect . check the ingredients on ketchup , bologna , spaghetti sauce , soy milk , sports drinks , fish sticks , and peanut butter . you 'll find sugar hiding in most of those products . in fact , you 'll find added sugars in three-quarters of the more than 600,000 items available in grocery stores . but how is sugar hiding ? ca n't you just look on food labels ? it 's not that easy . just like your friend robert might go by bob , robby , rob , bobby , or roberto , added sugar has a lot of aliases . and by a lot , we do n't mean five or six , try fifty-six . there 's brown rice syrup , barley malt , demerara , florida crystals , muscovado , and , of course , high fructose corn syrup , sometimes called hfcs , or corn sugar . even sugar 's tricky nicknames have nicknames . grape or apple concentrate has the same effects on your body as its 55 sugary twins . and even though organic evaporated cane juice sounds healthy , when you evaporate it , you get sugar ! chemically speaking , it 's all the same . and even trickier , when multiple added types of sugars are used in one type of product , they get buried down in a long list of ingredients , so the sugar content might appear to be okay , but when you add them all together , sugar can be the single biggest ingredient . currently , the fda does n't suggest a recommended daily limit for sugar , so it 's hard to tell if this 65 grams in a bottle of soda is a little or a lot . but the world health organization recommends limiting sugar to just 5 % of your total calories , or about 25 grams per day . so , 65 grams is well over twice that amount . but just what is sugar ? what 's the difference between glucose and fructose ? well , both are carbohydrates with the same chemical composition of carbon , hydrogen , and oxygen . but they have very different structures and behave quite differently in our bodies . glucose is the best source of energy for nearly all organisms on earth . it can be metabolized by all organs in the body . fructose , on the other hand , is metabolized primarily in the liver , and when your liver gets overloaded with sweet , sweet fructose , the excess is metabolized to fat . fresh fruits actually contain fructose , but it 's naturally occurring and does n't cause an overload because the fiber in fruit slows its absorption . this gives your liver the time it needs to do its job . it 's sugar that makes cookies chewy and candy crunchy . it even turns bread crust a beautiful , golden brown . it 's also a great preservative ; it does n't spoil or evaporate , so the foods it 's added to are easier to store and ship long distances and tend to be cheaper . that 's why sugar is hiding everywhere . actually , it might be easier to list the foods that added sugar is n't hiding in , things like : vegetables , eggs , meats , fish , fruit , raw nuts , even your kitchen sink . simply choosing water over soda , juices , and sports drinks is a great way to avoid hidden added sugar . at the very least , try to pay attention to food labels , so you can keep your sugar intake at a healthy level . because in this game of hide and seek , every time you do n't find added sugar , you win !
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it 's also a great preservative ; it does n't spoil or evaporate , so the foods it 's added to are easier to store and ship long distances and tend to be cheaper . that 's why sugar is hiding everywhere . actually , it might be easier to list the foods that added sugar is n't hiding in , things like : vegetables , eggs , meats , fish , fruit , raw nuts , even your kitchen sink . simply choosing water over soda , juices , and sports drinks is a great way to avoid hidden added sugar . at the very least , try to pay attention to food labels , so you can keep your sugar intake at a healthy level .
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which is not a kind of added sugar ?
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mysteries of vernacular : zero , a number that indicates an absence of units . in order to understand the genesis of the word zero , we must begin with the very origins of counting . the earliest known archaeological evidence of counting dates back approximately 37,000 years and is merely a series of notches in bone . it was n't until around 2500 b.c . that the first written number system began to take form in mesopotamia , using the units one , ten , and sixty . fast forward another three millennia to seventh century india where mathematicians used a single dot to distinguish between numbers like 25 , 205 , and 250 . employed as both a placeholder and a number , this all-powerful dot eventually morphed into the symbol we know today . the word zero comes from the arabic safira , whose literal translation is empty . passing through italian as zefiro , zero came into english in the seventeenth century . a second descendant of the arabic root was adopted into english through old french as the word cipher . originally sharing the meaning empty with zero , cipher later came to describe a code , as early codes often used complicated substitutions between letters and numbers . from this shared empty origin , zero continues to represent the number that represents nothing .
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it was n't until around 2500 b.c . that the first written number system began to take form in mesopotamia , using the units one , ten , and sixty . fast forward another three millennia to seventh century india where mathematicians used a single dot to distinguish between numbers like 25 , 205 , and 250 .
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when and where did the first written numeral system begin to take form ?
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if you 've ever floated on an ocean swell , you 'll know that the sea moves constantly . zoom out , and you 'll see the larger picture : our earth , covered by 71 percent water , moving in one enormous current around the planet . this intimidating global conveyor belt has many complicated drivers , but behind it all is a simple pump that moves water all over the earth . the process is called thermohaline circulation , and it 's driven by a basic concept : the concentration gradient . let 's leave the ocean for one moment and imagine we 're in an empty room with lots of roombas sardined together in one corner . turn them all on at once and the machines glide outwards bumping into and away from each other until the room is filled with an evenly spaced distribution . the machines have moved randomly towards equilibrium , a place where the concentration of a substance is equally spread out . that 's what happens along a concentration gradient , as substances shift passively from a high , or squashed , concentration , to a lower , more comfortable one . how does this relate to ocean currents and thermohaline circulation ? thermo means temperature , and haline means salt because in the real world scenario of the sea , temperature and salinity drive the shift from high to low concentrations . let 's put you back in the ocean to see how this works . snap ! you 're transformed into a molecule of surface water , off the temperate coast of new york surrounded by a zillion rowdy others . here , the sun 's rays act as an energizer that set you and the other water molecules jostling about , bouncing off each other like the roombas did . the more you spread out , the less concentrated the water molecules at the surface become . through this passive motion , you move from a high to a lower concentration . let 's suspend the laws of physics for a moment , and pretend that your molecular self can plunge deep down into the water column . in these colder depths , the comparative lack of solar warmth makes water molecules sluggish , meaning they can sit quite still at high concentrations . no jostling here . but seeking relief from the cramped conditions they 're in , they soon start moving upwards towards the roomier situation at the surface . this is how temperature drives a shift of water molecules from high to low concentrations , towards equilibrium . but sea water is made up of more than just h2o . there are a great deal of salt ions in it as well . and like you , these guys have a similar desire for spacious real estate . as the sun warms the sea , some of your fellow water molecules evaporate from the surface , increasing the ration of salt to h2o . the crowded salt ions left behind notice that lower down , salt molecules seem to be enjoying more space . and so an invasion begins , as they too move downwards in the water column . in the polar regions , we see how this small local process effects global movement . in the arctic and antarctic , where ice slabs decorate the water 's surface , there 's little temperature difference between surface and deeper waters . it 's all pretty cold . but salinity differs , and in this scenario , that 's what triggers the action . here , the sun 's rays melt surface ice , depositing a new load of water molecules into the sea . that not only increases the proximity between you and other water molecules , leaving you vying for space again , but it also conversely dilutes the concentration of salt ions . so , down you go , riding along the concentration gradient towards more comfortable conditions . for salt ions , however , their lower concentration at the surface , acts like an advertisement to the clamoring masses of salt molecules below who begin their assent . in both temperate and polar regions , this passive motion along a concentration gradient , can get a current going . and that is the starting point of the global conveyor called thermohaline circulation . this is how a simple concept becomes the mechanism underlying one of the largest and most important systems on our planet . and if you look around , you 'll see it happening everywhere . turn on a light , and it 's there . concentration gradients govern the flow of electricity , allowing electrons squashed together in one space to travel to an area of lower concentration when a channel is opened , which you do by flipping a switch . right now , in fact , there 's some gradient action going on inside you as you breath air into your lungs letting the concentrated oxygen in that air move passively out of your lungs and into your blood stream . we know that the world is filled with complex physical problems , but sometimes the first step towards understanding them can be simple . so when you confront the magnitude of the ocean 's currents , or have to figure out how electricity works , remember not to panic . understanding can be as simple as flipping a switch .
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so , down you go , riding along the concentration gradient towards more comfortable conditions . for salt ions , however , their lower concentration at the surface , acts like an advertisement to the clamoring masses of salt molecules below who begin their assent . in both temperate and polar regions , this passive motion along a concentration gradient , can get a current going . and that is the starting point of the global conveyor called thermohaline circulation .
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in temperature regions , the concentration of salt ions is highest :
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how much would you pay for a bouquet of tulips ? a few dollars ? a hundred dollars ? how about a million dollars ? probably not . well , how much would you pay for this house , or partial ownership of a website that sells pet supplies ? at different points in time , tulips , real estate and stock in pets.com have all sold for much more than they were worth . in each instance , the price rose and rose and then abruptly plummeted . economists call this a bubble . so what is exactly is going on with a bubble ? well , let 's start with the tulips to get a better idea . the 17th century saw the netherlands enter the dutch golden age . by the 1630s , amsterdam was an important port and commercial center . dutch ships imported spices from asia in huge quantities to earn profits in europe . so amsterdam was brimming with wealthy , skilled merchants and traders who displayed their prosperity by living in mansions surrounded by flower gardens . and there was one flower in particularly high demand : the tulip . the tulip was brought to europe on trading vessels that sailed from the east . because of this , it was considered an exotic flower that was also difficult to grow , since it could take years for a single tulip to bloom . during the 1630s , an outbreak of tulip breaking virus made select flowers even more beautiful by lining petals with multicolor , flame-like streaks . a tulip like this was scarcer than a normal tulip and as a result , prices for these flowers started to rise , and with them , the tulip 's popularity . it was n't long before the tulip became a nationwide sensation and tulip mania was born . a mania occurs when there is an upward movement of price combined with a willingness to pay large sums of money for something valued much lower in intrinsic value . a recent example of this is the dot-com mania of the 1990s . stocks in new , exciting websites were like the tulips of the 17th century . everybody wanted some . the more people who wanted the tulip , the higher the price could go . at one point , a single tulip bulb sold for more than ten times the annual salary of a skilled craftsman . in the stock market , the price of stock is based on the supply and demand of investors . stock prices tend to rise when it seems like a company will earn more in the future . investors might then buy more of the stock , raising the prices even further due to an increased demand . this can result in a feedback loop where investors get caught up in the hype and ultimately drive prices far above intrinsic value , creating a bubble . all that is needed for a mania to end and for a bubble to burst is the collective realization that the price of the stock , or a tulip , far exceeds its worth . that 's what happened with both manias . suddenly the demand ended . prices were pushed to staggering lows , and pop ! the bubbles burst , and the market crashed . today , scholars work long and hard trying to predict what causes a bubble and how to avoid them . tulip mania is an effective illustration of the underlying principles at work in a bubble and can help us understand more recent examples like the real estate bubble of the late 2000s . the economy will continue to go through phases of booms and busts . so while we wait for the next mania to start , and the next bubble to burst , treat yourself to a bouquet of tulips and enjoy the fact that you did n't have to pay an arm and a leg for them .
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a tulip like this was scarcer than a normal tulip and as a result , prices for these flowers started to rise , and with them , the tulip 's popularity . it was n't long before the tulip became a nationwide sensation and tulip mania was born . a mania occurs when there is an upward movement of price combined with a willingness to pay large sums of money for something valued much lower in intrinsic value .
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the tulip mania bubble burst when _____ .
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translator : andrea mcdonough reviewer : bedirhan cinar you might have heard that we 're running out of fresh water . this might sound strange to you because , if you live in a place where water flows freely from the tap or shower at any time , it sure does n't seem like a big deal . it 's just there , right ? wrong ! the only obvious thing about fresh water is how much we need it . because it 's essential to life , we need to think about it carefully . right now , at this very moment , some people , women and girls in particular , walk hours and miles per day to get fresh water , and even then , it may not be clean . every 15 seconds , a child dies due to water-born diseases . this is tragic ! the most compelling reasons to think about fresh water , therefore , have to do with what we might call the global common good . this is not something we normally think about , but it means recognizing how much fresh water matters for the flourishing of human and non-human life on earth now and in the future . how do we think about something as local as our faucets and as global as fresh water ? is there a connection between them ? many people assume that fresh water shortages are due to individual wastefulness : running the water while you brush your teeth , for example , or taking really long showers . most of us assume , therefore , that water shortages can be fixed by improving our personal habits : taking shorter showers or turning off the water while we brush our teeth . but , global fresh water scarcity neither starts nor ends in your shower . globally , domestic use of fresh water accounts for only 8 % of consumption , 8 % ! ! compare that to the 70 % that goes to agriculture and the 22 % that goes to industrial uses . now , hold up - you 're not off the hook ! individual habits are still part of the puzzle . you should still cultivate water virtue in your daily life , turn off the tap when you brush your teeth . but still , it 's true . taking shorter showers wo n't solve global problems , which is too bad . it would be much more straightforward and easier if virtuous , individual actions could do the trick . you 'd just stand there for 30 seconds less , and you 'd be done with that irksome , planet-saving task for the day . well , that 's not so much the case . agricultural and industrial patterns of water use need serious attention . how do our societies value water ? distribute it ? subsidize its use in agriculture ? incentivize its consumption or pollution ? these are all questions that stem from how we think about fresh water 's value . is it an economic commodity ? a human right ? a public good ? nobel prize winners , global water justice activists , transnational institutions like the united nations , and even the catholic church are at work on the issue . but , it 's tricky , too , because the business of water became very profitable in the 20th century . and profit is not the same thing as the common good . we need to figure out how to value fresh water as a public good , something that 's vital for human and non-human life , now and in the future . now that 's a virtuous , collective task that goes far beyond your shower .
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but , global fresh water scarcity neither starts nor ends in your shower . globally , domestic use of fresh water accounts for only 8 % of consumption , 8 % ! ! compare that to the 70 % that goes to agriculture and the 22 % that goes to industrial uses .
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globally , domestic water use accounts for what percentage of consumption ?
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he was one of the most fearsome warlords who ever lived , waging an unstoppable conquest across the eurasian continent . but was genghis khan a vicious barbarian or a unifier who paved the way for the modern world ? we 'll see in `` history vs. genghis khan . '' `` order , order . now who 's the defendant today ? khan ! '' `` i see your honor is familiar with genghis khan , the 13th century warlord whose military campaigns killed millions and left nothing but destruction in their wake . '' `` objection . first of all , it 's pronounced genghis kahn . '' `` really ? '' `` in mongolia , yes . regardless , he was one of the greatest leaders in human history . born temüjin , he was left fatherless and destitute as a child but went on to overcome constant strife to unite warring mongol clans and forge the greatest empire the world had seen , eventually stretching from the pacific to europe 's heartland . '' `` and what was so great about invasion and slaughter ? northern china lost 2/3 of its population . '' `` the jin dynasty had long harassed the northern tribes , paying them off to fight each other and periodically attacking them . genghis khan was n't about to suffer the same fate as the last khan who tried to unite the mongols , and the demographic change may reflect poor census keeping , not to mention that many peasants were brought into the khan 's army . '' `` you can pick apart numbers all you want , but they wiped out entire cities , along with their inhabitants . '' `` the khan preferred enemies to surrender and pay tribute , but he firmly believed in loyalty and diplomatic law . the cities that were massacred were ones that rebelled after surrendering , or killed as ambassadors . his was a strict understanding of justice . '' `` multiple accounts show his army 's brutality going beyond justice : ripping unborn children from mothers ' wombs , using prisoners as human shields , or moat fillers to support siege engines , taking all women from conquered towns -- '' `` enough ! how barbaric ! '' `` is that really so much worse than other medieval armies ? '' `` that does n't excuse genghis khan 's atrocities . '' `` but it does make genghis khan unexceptional for his time rather than some bloodthirsty savage . in fact , after his unification of the tribes abolished bride kidnapping , women in the mongol ranks had it better than most . they controlled domestic affairs , could divorce their husbands , and were trusted advisors . temüjin remained with his first bride all his life , even raising her possibly illegitimate son as his own . '' `` regardless , genghis khan 's legacy was a disaster : up to 40 million killed across eurasia during his descendents ' conquests . 10 % of the world population . that 's not even counting casualties from the black plague brought to europe by the golden horde 's siege of kaffa . '' `` surely that was n't intentional . '' `` actually , when they saw their own troops dying of the plague , they catapulted infected bodies over the city walls . '' `` blech . '' `` the accounts you 're referencing were written over a hundred years after the fact . how reliable do you think they are ? plus , the survivors reaped the benefits of the empire genghis khan founded . '' `` benefits ? '' `` the mongol empire practiced religious tolerance among all subjects , they treated their soldiers well , promoted based on merit , rather than birth , established a vast postal system , and inforced universal rule of law , not to mention their contribution to culture . '' `` you mean like hulagu khan 's annihilation of baghdad , the era 's cultural capital ? libraries , hospitals and palaces burned , irrigation canals buried ? '' `` baghdad was unfortunate , but its kalif refused to surrender , and hulagu was later punished by berke khan for the wanton destruction . it was n't mongol policy to destroy culture . usually they saved doctors , scholars and artisans from conquered places , and transferred them throughout their realm , spreading knowledge across the world . '' `` what about the devastation of kievan rus , leaving its people in the dark ages even as the renaissance spread across western europe ? '' `` western europe was hardly peaceful at the time . the stability of mongol rule made the silk road flourish once more , allowing trade and cultural exchange between east and west , and its legacy forged russia and china from warring princedoms into unified states . in fact , long after the empire , genghis khan 's descendants could be found among the ruling nobility all over eurasia . '' `` not surprising that a tyrant would inspire further tyrants . '' `` careful what you call him . you may be related . '' `` what ? '' `` 16 million men today are descended from genghis khan . that 's one in ever 200 . '' for every great conqueror , there are millions of conquered . whose stories will survive ? and can a leader 's historical or cultural signifigance outweigh the deaths they caused along the way ? these are the questions that arise when we put history on trial .
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`` baghdad was unfortunate , but its kalif refused to surrender , and hulagu was later punished by berke khan for the wanton destruction . it was n't mongol policy to destroy culture . usually they saved doctors , scholars and artisans from conquered places , and transferred them throughout their realm , spreading knowledge across the world . ''
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which was not a feature of the mongol empire ?
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translator : andrea mcdonough reviewer : bedirhan cinar this is zeno of elea , an ancient greek philosopher famous for inventing a number of paradoxes , arguments that seem logical , but whose conclusion is absurd or contradictory . for more than 2,000 years , zeno 's mind-bending riddles have inspired mathematicians and philosophers to better understand the nature of infinity . one of the best known of zeno 's problems is called the dichotomy paradox , which means , `` the paradox of cutting in two '' in ancient greek . it goes something like this : after a long day of sitting around , thinking , zeno decides to walk from his house to the park . the fresh air clears his mind and help him think better . in order to get to the park , he first has to get half way to the park . this portion of his journey takes some finite amount of time . once he gets to the halfway point , he needs to walk half the remaining distance . again , this takes a finite amount of time . once he gets there , he still needs to walk half the distance that 's left , which takes another finite amount of time . this happens again and again and again . you can see that we can keep going like this forever , dividing whatever distance is left into smaller and smaller pieces , each of which takes some finite time to traverse . so , how long does it take zeno to get to the park ? well , to find out , you need to add the times of each of the pieces of the journey . the problem is , there are infinitely many of these finite-sized pieces . so , should n't the total time be infinity ? this argument , by the way , is completely general . it says that traveling from any location to any other location should take an infinite amount of time . in other words , it says that all motion is impossible . this conclusion is clearly absurd , but where is the flaw in the logic ? to resolve the paradox , it helps to turn the story into a math problem . let 's supposed that zeno 's house is one mile from the park and that zeno walks at one mile per hour . common sense tells us that the time for the journey should be one hour . but , let 's look at things from zeno 's point of view and divide up the journey into pieces . the first half of the journey takes half an hour , the next part takes quarter of an hour , the third part takes an eighth of an hour , and so on . summing up all these times , we get a series that looks like this . `` now '' , zeno might say , `` since there are infinitely many of terms on the right side of the equation , and each individual term is finite , the sum should equal infinity , right ? '' this is the problem with zeno 's argument . as mathematicians have since realized , it is possible to add up infinitely many finite-sized terms and still get a finite answer . `` how ? '' you ask . well , let 's think of it this way . let 's start with a square that has area of one meter . now let 's chop the square in half , and then chop the remaining half in half , and so on . while we 're doing this , let 's keep track of the areas of the pieces . the first slice makes two parts , each with an area of one-half the next slice divides one of those halves in half , and so on . but , no matter how many times we slice up the boxes , the total area is still the sum of the areas of all the pieces . now you can see why we choose this particular way of cutting up the square . we 've obtained the same infinite series as we had for the time of zeno 's journey . as we construct more and more blue pieces , to use the math jargon , as we take the limit as n tends to infinity , the entire square becomes covered with blue . but the area of the square is just one unit , and so the infinite sum must equal one . going back to zeno 's journey , we can now see how how the paradox is resolved . not only does the infinite series sum to a finite answer , but that finite answer is the same one that common sense tells us is true . zeno 's journey takes one hour .
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not only does the infinite series sum to a finite answer , but that finite answer is the same one that common sense tells us is true . zeno 's journey takes one hour .
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zeno of elea was :
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what if i told you that all illnesses , things like the cold , the flu , strep throat , came from wandering clouds of poisonous vapor ? you 'd probably think that absurd , and , do n't worry , it 's completely wrong . yet that 's actually what people thought caused diseases for several centuries . they called it miasma theory , and everyone from the public to the medical establishment accepted it . but by the 1840s , in the midst of devastating cholera outbreaks in london , a small group of scientists had grown skeptical . early microscopes had revealed the existence of tiny microorganisms , and they proposed that it was actually these germs that cause diseases , hence the name germ theory . though most people held onto their assumptions and strongly resisted this theory , its supporters were determined to prove them wrong by collecting compelling data . leading the charge was a physician named dr. john snow . dr . snow observed that cholera-infected patients experienced severe vomiting and diarrhea , symptoms of the gut as opposed to the lungs , and thought that perhaps the disease was transmitted through food or drink , not the air . after investigating previous outbreaks , he became convinced that cholera was spread through contaminated water sources . then , late in the summer of 1854 when cholera suddenly struck the soho district , a neighborhood in london very close to his own , dr . snow was hot on its trail . he requested the records for the deceased , and within the first week , there had already been 83 deaths . he mapped out where each of the deceased had lived and found that 73 of them resided close to the water pump on broad street . dr . snow strongly recommended shutting down the pump , and because he knew how unpopular germ theory was , he suggested that cholera was spread through a poison in the water instead of microorganisms , when presenting his case to governmental officials . they were unconvinced , but agreed to shut down the pump as an extra precaution . almost immediately , new cases of infection subsided . bolstered by his success , dr . snow was determined to connect the contaminated pump water to the disease . he found the story of a widow who had died of cholera and lived far away from soho , but had a servant bring her water from the broad street pump daily because she liked the taste . he also discovered a workhouse located around the corner from the broad street pump that housed hundreds of people , but only a handful had become infected , which dr . snow attributed to the fact that the workhouse had its own private well . finally , dr . snow heard of an infant who may have been one of the earliest victims of the outbreak . he learned that the child 's dirty diapers had been thrown into a cesspool right next to the public water pump on broad street . again , dr . snow presented his case , but even then , city officials spurned his theory , not wanting to admit that there was human waste in london 's water supply , or that they were wrong about miasma theory , which was , after all , hundreds of years old . it was n't until 1884 that dr . snow 's efforts were vindicated by dr. robert koch , who isolated the cholera-causing bacterium . koch developed a technique to grow pure cultures , and through a series of experiments , definitively proved that a specific bacterium directly cause disease . major contributions to germ theory also came from prolific scientist louis pasteur , whose study of microorganisms led to the development of the first vaccines . by challenging assumptions with data-driven research , these scientists discredited an age-old theory and sparked a revolution that was incredibly beneficial to public health . but all of this raises the question , what are the widely held scientific beliefs of today that our descendants will find ridiculous ? and as any scientist would tell you , a question is an excellent place to start .
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koch developed a technique to grow pure cultures , and through a series of experiments , definitively proved that a specific bacterium directly cause disease . major contributions to germ theory also came from prolific scientist louis pasteur , whose study of microorganisms led to the development of the first vaccines . by challenging assumptions with data-driven research , these scientists discredited an age-old theory and sparked a revolution that was incredibly beneficial to public health . but all of this raises the question , what are the widely held scientific beliefs of today that our descendants will find ridiculous ?
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germ theory has revolutionized public health . what are some ways that humankind has benefitted from this discovery ?
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which of these entities has evolved the ability to manipulate an animal many times its size ? the answer is all of them . these are all parasites , organisms that live on or inside another host organism , which they harm and sometimes even kill . parasite survival depends on transmitting from one host to the next , sometimes through an intermediate species . our parasites elegantly achieve this by manipulating their host 's behavior , sometimes through direct brain hijacking . for example , this is the gordian worm . one of its hosts , this cricket . the gordian worm needs water to mate , but the cricket prefers dry land . so once it 's big enough to reproduce , the worm produces proteins that garble the cricket 's navigational system . the confused cricket jumps around erratically , moves closer to water , and eventually leaps in , often drowning in the process . the worm then wriggles out to mate and its eggs get eaten by little water insects that mature , colonize land , and are , in turn , eaten by new crickets . and thus , the gordian worm lives on . and here 's the rabies virus , another mind-altering parasite . this virus infects mammals , often dogs , and travels up the animal 's nerves to its brain where it causes inflammation that eventually kills the host . but before it does , it often increases its host 's aggressiveness and ramps up the production of rabies-transmitting saliva , while making it hard to swallow . these factors make the host more likely to bite another animal and more likely to pass the virus on when it does . and now , meet ophiocordyceps , also known as the zombie fungus . its host of choice is tropical ants that normally live in treetops . after ophiocordyceps spores pierce the ant 's exoskeleton , they set off convulsions that make the ant fall from the tree . the fungus changes the ant 's behavior , compelling it to wander mindlessly until it stumbles onto a plant leaf with the perfect fungal breeding conditions , which it latches onto . the ant then dies , and the fungus parasitizes its body to build a tall , thin stalk from its neck . within several weeks , the stalk shoots off spores , which turn more ants into six-legged leaf-seeking zombies . one of humanity 's most deadly assailants is a behavior-altering parasite , though if it 's any consolation , it 's not our brains that are being hijacked . i 'm talking about plasmodium , which causes malaria . this parasite needs mosquitoes to shuttle it between hosts , so it makes them bite more frequently and for longer . there 's also evidence that humans infected with malaria are more attractive to mosquitoes , which will bite them and transfer the parasite further . this multi-species system is so effective , that there are hundreds of millions of malaria cases every year . and finally , there are cats . do n't worry , there probably are n't any cats living in your body and controlling your thoughts . i mean , probably . but there is a microorganism called toxoplasma that needs both cats and rodents to complete its life cycle . when a rat gets infected by eating cat feces , the parasite changes chemical levels in the rat 's brain , making it less cautious around the hungry felines , maybe even attracted to them . this makes them easy prey , so these infected rodents get eaten and pass the parasite on . mind control successful . there 's even evidence that the parasite affects human behavior . in most cases , we do n't completely understand how these parasites manage their feats of behavior modification . but from what we do know , we can tell that they have a pretty diverse toolbox . gordian worms seem to affect crickets ' brains directly . the malaria parasite , on the other hand , blocks an enzyme that helps the mosquitoes feed , forcing them to bite over and over and over again . the rabies virus may cause that snarling , slobbering behavior by putting the immune system into overdrive . but whatever the method , when you think about how effectively these parasites control the behavior of their hosts , you may wonder how much of human behavior is actually parasites doing the talking . since more than half of the species on earth are parasites , it could be more than we think .
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the rabies virus may cause that snarling , slobbering behavior by putting the immune system into overdrive . but whatever the method , when you think about how effectively these parasites control the behavior of their hosts , you may wonder how much of human behavior is actually parasites doing the talking . since more than half of the species on earth are parasites , it could be more than we think .
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what do all parasites have in common ?
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hi , i 'm john green , this is crash course us history and today we 're going to talk about what america 's best at : war . [ patriotic rock music ] uh , mr. green , the united states has actually only declared war 5 times in the last 230 years . oh me from the the past , you sniveling literalist . well today we 're going to talk about america 's first declared war , the war of 1812 , so called because historians are terrible at naming things . i mean the could have called it the revolutionary war : part deux , or the canadian cataclysm , or the war to facilitate future wars . but no , they just named it after the year it started . [ theme music ] i know this disappoints the military historians among you , but as usual , we 're gon na spend more time talking about the causes and effects of the war than the actual , like , killing parts , because ultimately it 's the ambiguity of the war of 1812 that makes it so interesting . the reason most often given for the war of 1812 was the british impressment of american sailors , whereby american sailors would be kidnapped and basically forced into british servitude . this disrupted american shipping and also seems like a reasonably obvious violation of american sovereignty , but it 's a little more complicated than that . first of all , there were many thousands of british sailors working aboard american ships so many of the sailors that the british captured were in fact british . which gets to the large point that citizenship at the time was a pretty slippery concept especially on the high seas . like , papers were often forged , and many sailors identified supposed american-ness through tattoos of like eagles and flags . and there were several reasons why a british sailor might like to become , or pretend to be , an american , including that the brits at the time were fighting napoleon in what historians , in their infinite creativity , called the napoleonic wars . and on that topic , britain 's impressment policy allowed them both to disrupt american shipping to france and get new british sailors to strengthen their war effort , which was annoying to the americans on a couple levels especially the french-loving republicans , which is a phrase that you do n't hear very often anymore . another reason often given for the war , was america 's crazy conspiratorial anglophobia . there was even a widespread rumor that british agents were buying up connecticut sheep in order to sabotage the textile industry , lest you worry that america 's fascination with conspiracy theories is new . so those pushing for war were known as war hawks , and the most famous among them was kentucky 's henry clay . they took the impressment of sailors as an affront to american national honor , but they also complained that britain 's actions were an affront to free trade , by which they meant america 's ability to trade with europeans other than great britain . and to be fair , the british were trying to regulate american trade . they even passed the orders in counsel which required american ships to dock in britain and pay tax before trading with other european nations . britain , we were an independent nation ! you ca n't do that kind of stuff ! we have a special relationship but it 's not that special ! but the problem with saying that this caused the war was that the orders had been in effect for five years before the war started . and they were rescinded in 1812 before the us declared war . although , admittedly , we did n't know about it because it did n't reach us until after we declared . there was no twitter . another reason for the war was canada . that 's right canada , american 's wanted you and who can blame them we your excellent healthcare and your hockey and your first rate national anthem . stan this is fun but enough with the # 1812problems . according to the virginia congressman john randolph , `` agrarian cupidity not maritime rights urges the war . we have heard but one word : canada , canada , canada . '' i 'm not here to criticize you john randolph but that 's actually three words . now some historians disagree with this but the relentless pursuit of new land certainly fits in with the jeffersonian model of an agrarian republic . and there 's another factor that figured into america 's decision to go to war : expansion into territory controlled by native americans . oh , it 's time for the mystery document ? the rules here are simple : i try to guess the author of the mystery document . usually i 'm wrong and i get shocked . all right , let ’ s see what we got here . `` you want , by your distinctions of indian tribes , in allotting to each a particular tract of land , to make them to war with each other . you never see an indian come and endeavor to make the white people do so . '' it 's tecumseh . drop the mic ... [ dinging noise ] is something that i would do except that the mic is actually attached to my shirt so there 's n– there 's no drama in this . clearly a native american criticism of white people , and i happen to know that that particular one comes from tecumseh and i do n't get shocked today . so it should n't come as a surprise that americans were continuing to push westward into territories where indians were living . i mean , this was a big reason for the louisiana purchase after all . by the beginning of the war , more than 400,000 settlers had moved into territories west of the original 13 colonies and they outnumbered american indians by a significant margin . some native groups responded with a measure of assimilation . cherokees like john ross wanted to become more `` civilized '' , that is , more white and farmer-y . and some of them did even adopt such civilized practices as written languages and slavery , the most civilized practice of all . [ sigh ] people are always like , `` why are n't you more celebratory of american history ? '' well , why is n't there more to celebrate ? but other indians wanted to resist . the best known of these were the aforementioned tecumseh and his brother tensk – stan , can you just put it on the screen ? [ tenskwatawa on screen ] yes . let 's just enjoy looking at that . right , that 's just for all you visual learners . so he was also known as the prophet , because of his religious teachings , and also because of the pronunciation issues . the prophet encouraged indians , especially those living in and around the settlement of prophetstown , to abandon the ways of the whites , primarily in the form of alcohol and manufactured consumer goods . so stop drinking alcohol and eating refined sugars – this guy sounds like my doctor ! tecumseh was more militant ; attempting to revive neolin 's idea of pan-indianism and actively resisting white settlement . as he put it , `` sell a country , why not sell the air , the great sea , as well as the earth ? did not the great spirit make them all for the use of his children ? '' the americans responded to this reasonable criticism in the traditional manner – with guns . william henry harrison destroyed the native settlement at prophetstown in what would become known as the battle of tippecanoe . he would later ride that fame all the way to the presidency in 1840 and then – spoiler alert : he would give the longest inauguration address ever , catch a cold , and die 40 days later . let that be a lesson to you , american politicians : long speeches ? fatal ! so i just painted a pretty negative picture of the american treatment of the indians – because it was awful . but i have n't mentioned how this relates to the war of 1812 . the americans were receiving reports that the british were encouraging tecumseh , which they probably were . and the important thing to remember here is that the war of 1812 , like the seven years war and the american revolution was also a war against indians . and as in those other two wars , the indians were the biggest losers . and not in the cool way of biggest loser where , like , trainer bob helps you lose weight , but in the really sad way , where your entire civilization gets john c. calhouned . so the war of 1812 was the first time that the united states declared war on anybody . it was also the smallest margin of a declaration of war vote : 79 to 49 in the house and 19 to 13 in the senate . northern states , which relied on trade a lot , did n't want to go to war , while southern and western states , which were more agrarian and wanted expansion to get land for farming and slavery , did . the closeness of the vote reflects a profound ambivalence about the war . as henry adams wrote , `` many nations have gone to war in pure gaiety of the heart , but perhaps the united states were the first to force themselves into a war they dreaded , in the hope that the war itself might create the spirit they lacked . '' do n't worry , henry adams ! in the future we 're gon na get pretty gaiety of heart-ish about war . anyway , as an actual war , the war of 1812 was something of a farce . let 's go to the thought bubble . the us army numbered 10-12 thousand and its officers were sunk into either sloth , ignorance , or habits of intemperate drinking . the us navy had 17 ships . great britain had 1,000 . also , america had very little money , britain collected 40 times more tax revenue than the us . but britain was busy fighting napoleon , which is why they did n't really start kicking america 's butt until 1814 , after napoleon was defeated . napoleon 's defeat was also the practice of impressment , since britain did n't need so many sailors anymore . initially , much of the war consisted of america 's attempts to take canada , which any map will show you went smashingly . americans were confident the canadians would rush to join the us . when marching from detroit , general william hull informed the canadians that , `` you will be emancipated from tyranny and oppression and restored to the dignified station of free men . '' and the canadians were like , `` yeah , we 're okay actually . '' and so the british in canada , with their indian allies , went ahead and captured detroit and then forced hull 's surrender . america 's lack of success in canada was primarily attributable to terrible strategy . they might have succeeded if they 'd taken montreal , but they did n't want to march through northern new york because it was full of federalists who were opposed to the war . instead they concentrated on the west , that is , the area around detroit , where fighting went back and forth . the british found much more success , even seizing washington dc and burning the white house . in the course of the battle , british admiral george cockburn , overseeing the destruction of a newspaper printing house , told the forces that took the city , `` be sure that all the cs are destroyed , so that the rascals can not any longer abuse my name . it 's hard out there for a cockburn . thanks , thought bubble . given these problems it 's amazing there were any american successes , but there were . the battleship uss constitution broke the myth of british naval invincibility when cannonballs bounced off it and earned it the nickname `` old ironsides '' . oliver hazard perry defeated a british fleet , in , of all places , lake erie . at the battle of the thames , william harry harrison defeated tecumseh . and the battle of horseshoe ben showed one of the reasons why indians were defeated when andrew jackson played one group of creeks against another group of creeks and cherokees . 800 indians were killed in that battle . and speaking of jackson , the most notable american victory of the war was the battle of new orleans , which catapulted him to prominence . he lost only 71 men while inflicting 2,036 british casualties . of course , the most memorable thing about the battle is that it took place two weeks after the peace treaty ending the war had been signed . but hey , that 's not jackson 's fault . again – no twitter , # 1815problems . the treaty of ghent , which ended the war , proved just how necessary the war had been : not at all . no territory changed hands when negotiations started . and in august 1814 , the british asked for northern maine , demilitarization of the great lakes , and some territory to create an independent nation for the indians , and the northwest . but none of that happened , not because the u.s. was in a particularly good negotiating position , but it would have been awkward for great britain to carve out pieces of the us , and then tell russia and prussia that they could n't take pieces of europe for themselves to celebrate their victory in the napoleonic wars . there were no provisions in the treaty about impressment or free trade and basically the treaty returned everything to the status quo . so , neither the us or great britain actually won . but the indians suffered significant casualties and gave up even more territory , definitely lost . so with a treaty like that , the war must have had a negligible impact on american history , right ? except , no ; the war of 1812 confirmed that the us would exist . britain would never invade american again ( until 1961 ) . i mean the us were good customers , and great britain was happy to let them trade , as long as that trade was n't helping a french dictator . the war launched andrew jackson 's career and solidified the settlement and conquest of land east of the mississippi river . and our lack of success in canada reinforced canadian nationalism while also ensuring that instead of becoming one great nation , we would forever be canada 's pants . the war also spelled the end of the federalist party , which tried in 1815 with the hartford convention to change the constitution . in retrospect , the hartford convention proposals actually look pretty reasonable . they wanted to eliminate the clause wherein black people were counted as 3/5 of a human , and require a 2/3 congressional majority to declare war . but because they had their convention right before jackson 's victory at new orleans , they only came off looking unpatriotic and out of touch , as the elite so often do . it 's hard to argue that the americans really won the war of 1812 , but we felt like we won , and nothing unleashes national pride like war winning . the nationalistic fervor that emerged in the early 19th century , was , like most things , good news for some and bad news for others . but what ’ s important to remember , regardless of whether you 're an american , is that after 1812 , the united states saw itself not just as an independent nation but as a big player on the world stage . for better and for worse , that 's a gig we 've held onto . and no matter how you feel about america 's international interventions , you need to remember , it did n't begin in afghanistan or even europe ; it started with freakin ' canada . thanks for watching , i 'll see you next week . crash course is produced and directed by stan muller . the script supervisor is meredith danko . our show is written by my high school history teacher raoul meyer and myself . our associate producer is danica johnson . and our graphics team is thought cafe . if you have questions about today 's video , you can ask them in comments , where they will be answered by our team of historians . we also accept suggestions for libertage captions . thanks for watching crash course and as we say in my hometown : do n't forget to be awesome . goodbye ! do n't forget to subscribe !
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there was even a widespread rumor that british agents were buying up connecticut sheep in order to sabotage the textile industry , lest you worry that america 's fascination with conspiracy theories is new . so those pushing for war were known as war hawks , and the most famous among them was kentucky 's henry clay . they took the impressment of sailors as an affront to american national honor , but they also complained that britain 's actions were an affront to free trade , by which they meant america 's ability to trade with europeans other than great britain .
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why were war hawks pushing for war ?
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mysteries of vernacular : ukulele , a small , four-stringed guitar . oddly enough , the word ukulele , in its native hawaiian , literally translates to jumping flea . even more surprising , the instrument itself did not originate in hawaii . so , how did a hawaiian word come to describe a non-hawaiian instrument ? back in the late 1800s , king kalākaua was the last reigning king of the kingdom of hawaii . he was nicknamed `` the merry monarch '' because of his joy for life and , in particular , his love of music . in the king 's court , there was a former british army officer named edward purvis . though a small man , he was quite lively , and his nickname was `` jumping flea , '' `` ukulele '' in hawaiian . like the king , he was a great lover of music . in 1879 , a group of portuguese immigrants arrived on the islands of hawaii , bringing with them a small , four-stringed guitar known as a braguinha . purvis was immediately taken with the instrument and helped spread its popularity throughout the king 's court . as the story goes , it was not long before his nickname , ukulele , jumped from the man to his favorite instrument . as demand grew , several portuguese families began to manufacture the minuscule guitar on the islands , making small modifications until it became the same ukulele we recognize today .
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mysteries of vernacular : ukulele , a small , four-stringed guitar . oddly enough , the word ukulele , in its native hawaiian , literally translates to jumping flea . even more surprising , the instrument itself did not originate in hawaii .
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what is the difference between a loanword ( like ukulele ) and a loan translation ? what are some examples of each ?
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translation - marie de hert in j.r.r . 's world , gandalf is one of five wizards sent by the valar to guide the inhabitants of middle earth in their struggles against the dark force of sauron . gandalf 's body was mortal , subject to the physical rules of middle earth , but his spirit was immortal , as seen when he died as gandalf the grey and resurrected as gandalf the white . according to the wachowski 's script , an awakened human only has to link up and hack the neon binary code of the matrix to learn how to fly a helicopter in a matter of seconds . or if you are the one , or one of the ones , you do n't even need a helicopter , you just need a cool pair of shades . cheshire cats can juggle their own heads . ipads are rudimentary . no quidditch match ends until the golden snitch is caught . and the answer to the ultimate question of life , the universe , and everything is most certainly 42 . just like real life , fictional worlds operate consistently within a spectrum of physical and societal rules . that 's what makes these intricate worlds believable , comprehensible , and worth exploring . in real life , the law of gravity holds seven book sets of `` harry potter '' to millions of bookshelves around the world . we know this to be true , but we also know that ever since j.k. typed the words wizard , wand , and `` wingardium leviosa , '' that law of gravity has ceased to exist on the trillions of pages resting between those bookends . authors of science fiction and fantasy literally build worlds . they make rules , maps , lineages , languages , cultures , universes , alternate universes within universes , and from those worlds sprout story , after story , after story . when it 's done well , readers can understand fictional worlds and their rules just as well as the characters that live in them do and sometimes , just as well or even better than the reader understands the world outside of the book . but how ? how can human-made squiggles on a page reflect lights into our eyes that send signals to our brains that we logically and emotionally decode as complex narratives that move us to fight , cry , sing , and think , that are strong enough not only to hold up a world that is completely invented by the author , but also to change the reader 's perspective on the real world that resumes only when the final squiggle is reached ? i 'm not sure anyone knows the answer to that question , yet fantastical , fictional worlds are created everyday in our minds , on computers , even on napkins at the restaurant down the street . the truth is your imagination and a willingness to , figuratively , live in your own world are all you need to get started writing a novel . i did n't dream up hogwarts or the star wars ' cantina , but i have written some science thrillers for kids and young adults . here are some questions and methods i 've used to help build the worlds in which those books take place . i start with a basic place and time . whether that 's a fantasy world or a futuristic setting in the real world , it 's important to know where you are and whether you 're working in the past , present , or future . i like to create a timeline showing how the world came to be . what past events have shaped the way it is now ? then i brainstorm answers to questions that draw out the details of my fictional world . what rules are in place here ? this covers everything from laws of gravity , or not , to the rules of society and the punishments for individuals who break them . what kind of government does this world have ? who has power , and who does n't ? what do people believe in here ? and what does this society value most ? then it 's time to think about day-to-day life . what 's the weather like in this world ? where do the inhabitants live and work and go to school ? what do they eat and how do they play ? how do they treat their young and their old ? what relationships do they have with the animals and plants of the world ? and what do those animals and plants look like ? what kind of technology exists ? transportation ? communication ? access to information ? there 's so much to think about ! so , spend some time living in those tasks and the answers to those questions , and you 're well on your way to building your own fictional world . once you know your world as well as you hope your reader will , set your characters free in it and see what happens . and ask yourself , `` how does this world you created shape the individuals who live in it ? and what kind of conflict is likely to emerge ? '' answer those questions , and you have your story . good luck , future world-builder !
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answer those questions , and you have your story . good luck , future world-builder !
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in building a world , an author of futuristic fiction would be most likely to focus on :
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translator : andrea mcdonough reviewer : bedirhan cinar being human , we each view ourselves as a unique and independent individual , but we 're never alone ! millions of microscopic beings inhabit our bodies , and no two bodies are the same . each is a different habitat for microbial communities : from the arid deserts of our skin , to the villages on our lips , and the cities in our mouths . even every tooth is its own distinctive neighborhood , and our guts are teaming metropolises of interacting microbes . and in these bustling streets of our guts , we see a constant influx of food , and every microbe has a job to do . here 's a cellulolytic bacteria , for example . their one job is to break down cellulose , a common compound in vegetables , into sugars . those simple sugars then move along to the respirators , another set of microbes that snatch up these simple sugars and burn them as fuel . as food travels through our digestive tract , it reaches the fermentors who extract energy from these sugars by converting them into chemicals , like alcohol and hydrogen gas , which they spew out as waste products . deeper in the depths of our gut city , the syntrophs eke out a living off the fermenters ' trash . at each step of this process , energy is released , and that energy is absorbed by the cells of the digestive tract . this city we just saw is different in everyone . every person has a unique and diverse community of gut microbes that can process food in different ways . one person 's gut microbes may be capable of releasing only a fraction of the calories that another person 's gut microbes can extract . so , what determines the membership of our gut microbial community ? well , things like our genetic makeup and the microbes we encounter throughout our lives can contribute to our microbial ecosystems . the food we eat also influences which microbes live in our gut . for example , food made of complex molecules , like an apple , requires a lot of different microbial workers to break it down . but , if a food is made of simple molecules , like a lollipop , some of these workers are put out of a job . those workers leave the city , never to return . what does n't function well are gut microbial communities with only a few different types of workers . for example , humans who suffer from diseases like diabetes or chronic gut inflamation typically have less microbial variety in their guts . we do n't fully understand the best way to manage our individual microbial societies , but it is likely that lifestyle changes , such as eating a varied diet of complex , plant-based foods , can help revitalize our microbial ecosystems in our gut and across the entire landscape of our body . so , we are really not alone in our body . our bodies are homes to millions of different microbes , and we need them just as much as they need us . as we learn more about how our microbes interact with each other and with our bodies , we will reveal how we can nurture this complex , invisible world that shapes our personal identity , our health , and our well-being .
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those simple sugars then move along to the respirators , another set of microbes that snatch up these simple sugars and burn them as fuel . as food travels through our digestive tract , it reaches the fermentors who extract energy from these sugars by converting them into chemicals , like alcohol and hydrogen gas , which they spew out as waste products . deeper in the depths of our gut city , the syntrophs eke out a living off the fermenters ' trash .
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as food travels through our digestive tract , it reaches the fermenters . what do they do ?
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now , my subject is success , so people sometimes call me a `` motivational speaker . '' but i want you to know right up front i 'm not a motivational speaker . i could n't pass the height requirement . ( laughter ) and i could n't motivate anybody . my employees actually call me a de-motivational speaker . ( laughter ) what i try to be is an informational speaker . i went out and found out some information about success , and i 'm just here to pass it on . and my story started over ten years ago , on a plane . i was on my way to the ted conference in california , and in the seat next to me was a teenage girl , and she came from a really poor family , but she wanted to get somewhere in life . and as i tapped away on my computer , she kept asking me questions , and then out of the blue , she asked , `` are you successful ? '' i said , `` no , i 'm not successful . '' terry fox , my hero , now there 's a big success . he lost a leg to cancer , then ran thousands of miles and raised millions for cancer research . or bill gates , a guy who owns his own plane and does n't have to sit next to some kid asking him questions . ( laughter ) but then i told her about some of the stuff i 'd done . i love communications , and i 've won lots of awards in marketing . i love running , and i still sometimes win my age group , old farts over 60 . ( laughter ) my fastest marathon is two hours and 43 minutes to run the 26 miles , or 42 kilometers . i 've run over 50 marathons , in all 7 continents . this was a run my wife and i did up the inca trail to machu picchu in peru . and to qualify for the 7 continents , we had to run a marathon in antarctica . but when we got there , it did n't look nice and calm like this , it looked like this . the waves were so high , we could n't get to shore . so we sailed 200 miles further south to where the seas were calm and ran the entire 26-mile marathon on the boat . 422 laps around the deck of that little boat . my wife and i have also climbed two of the world 's seven summits , the highest mountains on each continent . we climbed aconcagua , the highest mountain on the american continent , and kilimanjaro , the highest mountain in africa . well , to be honest , i puked my way to the top of kilimanjaro , i got altitude sickness . i got no sympathy from my wife . she passed me and did a lap around the top while i was still struggling up there . in spite of that , we 're still together and have been for over 35 years . ( applause ) i 'd say that 's a success these days . so i said to the girl , `` well , you know , i guess i have had some success . '' and then she said , `` okay , so are you a millionaire ? '' ( laughter ) now , i did n't know what to say , because when i grew up , it was bad manners to talk about money . but i figured i 'd better be honest , and i said , `` yeah . i 'm a millionaire . but i do n't know how it happened . i never went after the money , and it 's not that important to me . '' she said , `` maybe not to you , but it is to me . i do n't want to be poor all my life . i want to get somewhere , but it 's never going to happen . '' i said , `` well , why not ? '' she said , `` well , you know , i 'm not very smart . i 'm not doing great in school . '' i said , `` so what ? i 'm not smart . i barely passed high school . i had absolutely nothing going for me . i was never voted most popular or most likely to succeed . i started a whole new category -- most likely to fail . but in the end , i did okay . so if i can do it , you can do it . '' and then she asked me the big question : `` okay , so what really leads to success ? '' i said , `` jeez , sorry . i do n't know . i guess somehow i did it . i do n't know how i did it . '' so i get off the plane and go to the ted conference , and i 'm standing in a room full of extraordinarily successful people in many fields -- business , science , arts , health , technology , the environment -- when it hit me : why do n't i ask them what helped them succeed , and find out what really leads to success for everyone ? so i was all excited to get out there and start talking to these great people , when the self-doubt set in . i mean , why would people want to talk to me ? i 'm not a famous journalist . i 'm not even a journalist . so i was ready to stop the project before it even began , when who comes walking towards me but ben cohen , the famous co-founder of ben and jerry 's ice cream . i figured it was now or never . i pushed through the self-doubt , jumped out in front of him , and said , `` ben , i 'm working on this project . i do n't even know what to ask you , but can you tell me what helped you succeed ? '' he said , `` yeah , sure , come on . let 's go for a coffee . '' and over coffee and ice cream , ben told me his story . now here we are over 10 years later , and i 've interviewed over 500 successful people face-to-face , and collected thousands of other success stories . i wanted to find the common factors for success in all fields , so i had to interview people in careers ranging from a to z . these are just the careers i interviewed beginning with the letter a , and in most cases more than one person . i interviewed six successful accountants , five corporate auditors , five astronauts who had been into space , four actors who had won the academy award for best actor , three of the world 's top astrophysicists , six of the world 's leading architects and , oh yeah , four nobel prize winners . yeah , i know it does n't start with a , but it 's kind of cool . ( laughter ) and i want to say a sincere thanks to all the great people that i 've interviewed over the years . this really is their story ; i 'm just the messenger . the really big job was taking all the interviews and analyzing them , word by word , line by line , and sorting them into all the factors that people said helped them succeed . and then you start to see the big factors that are common to most people 's success . altogether , i analyzed and sorted millions of words . do you know how much work that is ? that 's all i do , day and night -- sort and analyze . i 'll tell you , if i ever get my hands on that kid on the plane -- ( laughter ) actually , if i do , i 'll thank her . because i 've never had so much fun and met so many interesting people . and now , i can answer her question . i discovered the 8 traits successful people have in common , or the 8 to be great : love what you do ; work really hard ; focus on one thing , not everything ; keep pushing yourself ; come up with good ideas ; keep improving yourself and what you do ; serve others something of value , because success is n't just about me , me , me ; and persist , because there 's no overnight success . why did i pick these ? because when i added up all the comments in my interviews , more people said those 8 things helped them than anything else . the eight traits are really the heart of success , the foundation , and then on top we build the specific skills that we need for our particular field or career . technical skills , analytical skills , people skills , creative skills -- lots of other skills we can add on top , depending on our field . but no matter what field we 're in , these eight traits will be at the heart of our success . ( applause )
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why did i pick these ? because when i added up all the comments in my interviews , more people said those 8 things helped them than anything else . the eight traits are really the heart of success , the foundation , and then on top we build the specific skills that we need for our particular field or career .
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when i started interviewing people , i was shy , scared , and full of self-doubt . but i pushed through it and did over 500 interviews . i met wonderful people , got inspired , and learned a lot . and what i discovered from the interviews has helped a lot of people . so i ’ d recommend doing some interviews yourself . you never know where it might take you… name 5 people you know or admire in your community : a successful teacher , environmentalist , artist , engineer , dentist , police officer , ceo , etc . pick one person , make contact , and ask for an interview . most people are flattered you asked , and happy to help . write down some questions you could ask . i usually start with one question : `` what helped you succeed ? '' and go from there . do the interview . take notes or record what they say . it will be fun for both of you and you 'll learn a lot . summarize what helped them succeed and your conclusions .
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dating back at least to the time of socrates , some early societies decided that certain disputes , such as whether a person committed a particular crime , should be heard by a group of citizens . several centuries later , trial by jury was introduced to england , where it became a fundamental feature of the legal system , checking the government and involving citizens in decision-making . juries decided whether defendants would be tried on crimes , determined whether the accused defendants were guilty , and resolved monetary disputes . while the american colonies eventually cast off england 's rule , its legal tradition of the jury persisted . the united states constitution instructed a grand jury to decide whether criminal cases proceeded , required a jury to try all crimes , except impeachment , and provided for juries in civil cases as well . yet , in the us today , grand juries often are not convened , and juries decide less than 4 % of criminal cases and less than 1 % of civil cases filed in court . that 's at the same time as jury systems in other countries are growing . so what happened in the u.s. ? part of the story lies in how the supreme court has interpreted the constitution . it 's permitted plea bargaining , which now occurs in almost every criminal case . the way it works is the prosecutor presents the accused with a decision of whether to plead guilty . if they accept the plea , the case wo n't go in front of a jury , but they 'll receive a shorter prison sentence than they 'd get if a jury did convict them . the risk of a much greater prison sentence after a trial can frighten even an innocent defendant into taking a plea . between the 19th century and the 21st century , the proportion of guilty pleas has increased from around 20 % to 90 % , and the numbers continue to grow . the supreme court has permitted the use of another procedure that interferes with the jury called summary judgement . using summary judgement , judges can decide that civil trials are unnecessary if the people who sue have insufficient evidence . this is intended only for cases where no reasonable jury would disagree . that 's a difficult thing to determine , yet usage of summary judgement has stretched to the point where some would argue it 's being abused . for instance , judges grant fully , or in part , over 70 % of employers ' requests to dismiss employment discrimination cases . in other cases , both the person who sues and the person who defends forgo their right to go to court , instead resolving their dispute through a professional arbitrator . these are generally lawyers , professors , or former judges . arbitration can be a smart decision by both parties to avoid the requirements of a trial in court , but it 's often agreed to unwittingly when people sign contracts like employment applications and consumer agreements . that can become a problem . for example , some arbitrators may be biased towards the companies that give them cases . these are just some of the ways in which juries have disappeared . but could the disappearance of juries be a good thing ? well , juries are n't perfect . they 're costly , time-consuming , and may make errors . and they 're not always necessary , like when people can simply agree to settle their disputes . but juries have their advantages . when properly selected , jurors are more representative of the general population and do n't have the same incentives as prosecutors , legislators , or judges seeking reelection or promotion . the founders of the united states trusted in the wisdom of impartial groups of citizens to check the power of all three branches of government . and the jury trial itself has given ordinary citizens a central role in upholding the social fabric . so will the jury system in the u.s. survive into the future ?
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juries decided whether defendants would be tried on crimes , determined whether the accused defendants were guilty , and resolved monetary disputes . while the american colonies eventually cast off england 's rule , its legal tradition of the jury persisted . the united states constitution instructed a grand jury to decide whether criminal cases proceeded , required a jury to try all crimes , except impeachment , and provided for juries in civil cases as well . yet , in the us today , grand juries often are not convened , and juries decide less than 4 % of criminal cases and less than 1 % of civil cases filed in court .
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the jury in the united states was based on the jury in _________ .
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space : it 's where things happen . time : it 's when things happen . we can measure where things are and when things take place , but in modern physics , we realize when and where are actually part of the same question . because when it comes to understanding the universe , we need to replace three-dimensional space plus time with a single concept : four-dimensional space-time . we 'll explore and explain space-time in this series of animations . animations ? yeah . well , we 're not very animated are we ? sure we are ! look , i can go from here to here . whoa ! how 'd you get from here to there ? how fast did you go ? did you run ? walk ? did you even go in a straight line ? ah ! to answer that , you 'll need to make our cartoon physics look more like physics physics . you 'll need more panels . more panels , please ! okay , in each panel , andrew 's in a slightly different place . so i can see each one records where andrew is at a different time . that 's great . but it would be easier to see what 's going on if we could cut out all the hundreds of panels and stack them up like a flip book . right , now let 's flip through the book so that we can see one panel after another getting through 24 in every second . see ! i told you it was an animation . now you can see me walking along . drawing all those panels and putting them into a flip book is just one way of recording the way i 'm moving . it 's how animation , or even movies , work . as it turns out , at my walking speed , it takes two seconds to get past each fence post , and they 're spaced four meters apart . so we can calculate my velocity -- how fast i 'm moving through space - - is two meters per second . but i could 've worked that out from the panels without flipping through them . from the edge of the flip book , you can see all of the copies of the fence posts and all of the copies of andrew and he 's in a slightly different place in each one . now we can predict everything that will happen to andrew when we flip through 24 pages every second , including his speed of motion , just by looking . no need to flip through at all . the edge of this flip book is known as a space-time diagram of andrew 's journey through , you guessed it , space and time . we call the line that represents andrew 's journey his world line . if i jog instead of walking , i might be able to get past a fence post every second . he 's not very athletic . anyway , when we look at this new flip book from the edge , we can do the same analysis as before . the world line for andrew jogging is more tilted over than the world line for andrew walking . we can tell he 's going twice as fast as before without flipping the panels . but here 's the clever bit . in physics , it 's always good to view things from other perspectives . after all , the laws of physics should be the same for everyone or no one will obey them . so let 's rethink our cartoon and have the camera follow andrew jogging along as the fence posts approach and pass behind him . still viewing it as a flip book of panels , we do n't need to redraw anything . we simply move all of the cutout frames slightly until andrew 's tilted world line becomes completely vertical . to see why , let 's flip it . yes , now i 'm stationery , just jogging on the spot , in the center of the panel . on the edge of the flip book , my world line was going straight upwards . the fence posts are coming past me . it 's now their world lines that are tilted . this rearrangement of the panels is known as a galilean transformation , and it lets us analyze physics from someeone else 's perspective . in this case , mine . after all , it 's always good to see things from other points of view , especially when the viewers are moving at different speeds . so long as the speeds are n't too high . if you 're a cosmic ray moving at the speed of light , our flip book of your point of view falls apart . to stop that from happening , we 'll have to glue panels together . instead of a stack of separate panels , we 'll need a solid block of space-time , which we 'll come to in the next animation .
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you 'll need more panels . more panels , please ! okay , in each panel , andrew 's in a slightly different place . so i can see each one records where andrew is at a different time .
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we showed how spacetime diagrams are like the edge of a flipbook , and so can be created by stacking up a series of animation panels . a single panel tells us :
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what if electricity could travel forever without being diminished ? what if a computer could run exponentially faster with perfect accuracy ? what technology could those abilities build ? we may be able to find out thanks to the work of the three scientists who won the nobel prize in physics in 2016 . david thouless , duncan haldane , and michael kosterlitz won the award for discovering that even microscopic matter at the smallest scale can exhibit macroscopic properties and phases that are topological . but what does that mean ? first of all , topology is a branch of mathematics that focuses on fundamental properties of objects . topological properties do n't change when an object is gradually stretched or bent . the object has to be torn or attached in new places . a donut and a coffee cup look the same to a topologist because they both have one hole . you could reshape a donut into a coffee cup and it would still have just one . that topological property is stable . on the other hand , a pretzel has three holes . there are no smooth incremental changes that will turn a donut into a pretzel . you 'd have to tear two new holes . for a long time , it was n't clear whether topology was useful for describing the behaviors of subatomic particles . that 's because particles , like electrons and photons , are subject to the strange laws of quantum physics , which involve a great deal of uncertainty that we do n't see at the scale of coffee cups . but the nobel laureates discovered that topological properties do exist at the quantum level . and that discovery may revolutionize materials science , electronic engineering , and computer science . that 's because these properties lend surprising stability and remarkable characteristics to some exotic phases of matter in the delicate quantum world . one example is called a topological insulator . imagine a film of electrons . if a strong enough magnetic field passes through them , each electron will start traveling in a circle , which is called a closed orbit . because the electrons are stuck in these loops , they 're not conducting electricity . but at the edge of the material , the orbits become open , connected , and they all point in the same direction . so electrons can jump from one orbit to the next and travel all the way around the edge . this means that the material conducts electricity around the edge but not in the middle . here 's where topology comes in . this conductivity is n't affected by small changes in the material , like impurities or imperfections . that 's just like how the hole in the coffee cup is n't changed by stretching it out . the edge of such a topological insulator has perfect electron transport : no electrons travel backward , no energy is lost as heat , and the number of conducting pathways can even be controlled . the electronics of the future could be built to use this perfectly efficient electron highway . the topological properties of subatomic particles could also transform quantum computing . quantum computers take advantage of the fact that subatomic particles can be in different states at the same time to store information in something called qubits . these qubits can solve problems exponentially faster than classical digital computers . the problem is that this data is so delicate that interaction with the environment can destroy it . but in some exotic topological phases , the subatomic particles can become protected . in other words , the qubits formed by them ca n't be changed by small or local disturbances . these topological qubits would be more stable , leading to more accurate computation and a better quantum computer . topology was originally studied as a branch of purely abstract mathematics . thanks to the pioneering work of thouless , haldane , and kosterlitz , we now know it can be used to understand the riddles of nature and to revolutionize the future of technologies .
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that 's because these properties lend surprising stability and remarkable characteristics to some exotic phases of matter in the delicate quantum world . one example is called a topological insulator . imagine a film of electrons .
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why is the topological insulator special ?
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remember the time you fell off your bike or bumped your head on a sharp corner ? childhood injuries are things we 'd often like to forget , but our bodies often carry the memories in the form of scars . so what are these unwanted souvenirs and why do we keep them for so long after that unintended vacation to the emergency room ? the most common place we see scars are on our skin , a patch that looks slightly different from the normal skin around it . often , this is considered an unfortunate disfigurement , while other times , deliberate scarification has been used in both traditional and modern cultures , to mark a rite of passage or simply for aesthetic decoration . but the difference is n't only cosmetic . when we look at healthy skin tissue under a microscope , we see the cells that perform various functions connected by an extracellular matrix , or ecm . this is composed of structural proteins , like collagen , secreted by specialized fibroblast cells . well-arranged ecm allows for transportation of nutrients , cell-to-cell communication , and cell adhesion . but when a deep wound occurs , this arrangement is disrupted . during the process of wound healing , collagen is redeposited at the wound site , but instead of the basket-weave formation found in healthy tissue , the new ecm is aligned in a single direction , impeding inter-cell processes , and reducing durability and elasticity . to make matters worse , the healed tissue contains a higher proportion of ecm than before , reducing its overall function . in the skin , the overabundance of collagen interferes with its original functions , like producing sweat , controlling body temperature and even growing hair . the scar tissue is fragile , sensitive to changes in temperature and sensation , and should be kept in moist environments to maximize healing . this presence of excessive fibrous connective tissue in an organ is known as fibrosis , and if that term sounds familiar , it 's because our skin is not the only organ vulnerable to scarring . cystic fibrosis is a genetic disorder that causes scarring of the pancreas , while pulmonary fibrosis is a scarring of the lungs , resulting in shortness of breath . scarring of the heart and the buildup of ecm following a heart attack can inhibit its beating , leading to further heart problems . what 's common to all these conditions is that although it retains some of the original functions , the scar tissue formed after a wound is inferior to the native tissue it replaces . however , there is hope . medical researchers are now studying what causes fibroblast cells to secrete excessive amounts of collagen and how we can recruit the body 's other cells in regenerating and repopulating the damaged tissue . by learning how to better control wound healing and the formation of scar tissue , we can utilize the multi-billion-dollar budgets currently used to address the aftermath of wounding in a much more efficient manner , and help millions of people live better and healthier lives . but until then , at least some of our scars can help us remember to avoid the sorts of things that cause them .
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the scar tissue is fragile , sensitive to changes in temperature and sensation , and should be kept in moist environments to maximize healing . this presence of excessive fibrous connective tissue in an organ is known as fibrosis , and if that term sounds familiar , it 's because our skin is not the only organ vulnerable to scarring . cystic fibrosis is a genetic disorder that causes scarring of the pancreas , while pulmonary fibrosis is a scarring of the lungs , resulting in shortness of breath .
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which other organs , apart from those mentioned in the lesson , could also be vulnerable to becoming deficient following fibrosis ? why ?
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after the french revolution erupted in 1789 , europe was thrown into chaos . neighboring countries ' monarchs feared they would share the fate of louis xvi , and attacked the new republic , while at home , extremism and mistrust between factions lead to bloodshed . in the midst of all this conflict , a powerful figure emerged to take charge of france . but did he save the revolution or destroy it ? `` order , order , who 's the defendant today ? i do n't see anyone . '' `` your honor , this is napoléon bonaparte , the tyrant who invaded nearly all of europe to compensate for his personal stature-based insecurities . '' `` actually , napoléon was at least average height for his time . the idea that he was short comes only from british wartime propaganda . and he was no tyrant . he was safeguarding the young republic from being crushed by the european monarchies . '' `` by overthrowing its government and seizing power himself ? '' `` your honor , as a young and successful military officer , napoléon fully supported the french revolution , and its ideals of liberty , equality , and fraternity . but the revolutionaries were incapable of real leadership . robespierre and the jacobins who first came to power unleashed a reign of terror on the population , with their anti-catholic extremism and nonstop executions of everyone who disagreed with them . and the directory that replaced them was an unstable and incompetent oligarchy . they needed a strong leader who could govern wisely and justly . '' `` so , france went through that whole revolution just to end up with another all-powerful ruler ? '' `` not quite . napoléon 's new powers were derived from the constitution that was approved by a popular vote in the consulate . '' `` ha ! the constitution was practically dictated at gunpoint in a military coup , and the public only accepted the tyrant because they were tired of constant civil war . '' `` be that as it may , napoléon introduced a new constitution and a legal code that kept some of the most important achievements of the revolution in tact : freedom of religion abolition of hereditary privilege , and equality before the law for all men . '' `` all men , indeed . he deprived women of the rights that the revolution had given them and even reinstated slavery in the french colonies . haiti is still recovering from the consequences centuries later . what kind of equality is that ? '' `` the only kind that could be stably maintained at the time , and still far ahead of france 's neighbors . '' `` speaking of neighbors , what was with all the invasions ? '' `` great question , your honor . '' `` which invasions are we talking about ? it was the neighboring empires who had invaded france trying to restore the monarchy , and prevent the spread of liberty across europe , twice by the time napoléon took charge . having defended france as a soldier and a general in those wars , he knew that the best defense is a good offense . '' `` an offense against the entire continent ? peace was secured by 1802 , and other european powers recognized the new french regime . but bonaparte could n't rest unless he had control of the whole continent , and all he knew was fighting . he tried to enforce a european-wide blockade of britain , invaded any country that did n't comply , and launched more wars to hold onto his gains . and what was the result ? millions dead all over the continent , and the whole international order shattered . '' `` you forgot the other result : the spread of democratic and liberal ideals across europe . it was thanks to napoléon that the continent was reshaped from a chaotic patchwork of fragmented feudal and religious territories into efficient , modern , and secular nation states where the people held more power and rights than ever before . '' `` should we also thank him for the rise of nationalism and the massive increase in army sizes ? you can see how well that turned out a century later . '' `` so what would european history have been like if it were n't for napoléon ? '' `` unimaginably better/worse . '' napoléon seemingly unstoppable momentum would die in the russian winter snows , along with most of his army . but even after being deposed and exiled , he refused to give up , escaping from his prison and launching a bold attempt at restoring his empire before being defeated for the second and final time . bonaparte was a ruler full of contradictions , defending a popular revolution by imposing absolute dictatorship , and spreading liberal ideals through imperial wars , and though he never achieved his dream of conquering europe , he undoubtedly left his mark on it , for better or for worse .
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he was safeguarding the young republic from being crushed by the european monarchies . '' `` by overthrowing its government and seizing power himself ? '' `` your honor , as a young and successful military officer , napoléon fully supported the french revolution , and its ideals of liberty , equality , and fraternity .
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what were the factors that enabled napoleon to rise to power and explained his popularity ?
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imagine a police lineup where ten witnesses are asked to identify a bank robber they glimpsed fleeing the crime scene . if six of them pick out the same person , there 's a good chance that 's the real culprit , and if all ten make the same choice , you might think the case is rock solid , but you 'd be wrong . for most of us , this sounds pretty strange . after all , much of our society relies on majority vote and consensus , whether it 's politics , business , or entertainment . so it 's natural to think that more consensus is a good thing . and up until a certain point , it usually is . but sometimes , the closer you start to get to total agreement , the less reliable the result becomes . this is called the paradox of unanimity . the key to understanding this apparent paradox is in considering the overall level of uncertainty involved in the type of situation you 're dealing with . if we asked witnesses to identify the apple in this lineup , for example , we should n't be surprised by a unanimous verdict . but in cases where we have reason to expect some natural variance , we should also expect varied distribution . if you toss a coin one hundred times , you would expect to get heads somewhere around 50 % of the time . but if your results started to approach 100 % heads , you 'd suspect that something was wrong , not with your individual flips , but with the coin itself . of course , suspect identifications are n't as random as coin tosses , but they 're not as clear cut as telling apples from bananas , either . in fact , a 1994 study found that up to 48 % of witnesses tend to pick the wrong person out of a lineup , even when many are confident in their choice . memory based on short glimpses can be unreliable , and we often overestimate our own accuracy . knowing all this , a unanimous identification starts to seem less like certain guilt , and more like a systemic error , or bias in the lineup . and systemic errors do n't just appear in matters of human judgement . from 1993-2008 , the same female dna was found in multiple crime scenes around europe , incriminating an elusive killer dubbed the phantom of heilbronn . but the dna evidence was so consistent precisely because it was wrong . it turned out that the cotton swabs used to collect the dna samples had all been accidentally contaminated by a woman working in the swab factory . in other cases , systematic errors arise through deliberate fraud , like the presidential referendum held by saddam hussein in 2002 , which claimed a turnout of 100 % of voters with all 100 % supposedly voting in favor of another seven-year term . when you look at it this way , the paradox of unanimity is n't actually all that paradoxical . unanimous agreement is still theoretically ideal , especially in cases when you 'd expect very low odds of variability and uncertainty , but in practice , achieving it in situations where perfect agreement is highly unlikely should tell us that there 's probably some hidden factor affecting the system . although we may strive for harmony and consensus , in many situations , error and disagreement should be naturally expected . and if a perfect result seems too good to be true , it probably is .
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imagine a police lineup where ten witnesses are asked to identify a bank robber they glimpsed fleeing the crime scene . if six of them pick out the same person , there 's a good chance that 's the real culprit , and if all ten make the same choice , you might think the case is rock solid , but you 'd be wrong .
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consider a hostage situation where a crazed gunman kept 20 peopled detained in a house for a whole week . his face was on full view for a week . the hostages eventually go free and the gunman escapes . later the police capture a person who they think is the gunman . during an identity parade all 20 former hostages agree that the police have caught the correct man . what is the likelihood the police were correct ?
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[ ♪sustained note♪ ] [ flag flapping in breeze ] [ path of freedom ] [ ♪ music ♪ ] [ prisoners chattering ] [ ♪ music ♪ ] - this is a tough guy world , and we have to control all of their movement and their behavior [ roberta richman - rhode island dept . of corrections ] because that 's the way you keep an institution safe for everybody who lives in it . [ ♪ music ♪ ] we have everybody here— murderers and rapists , sex offenders , drug addicts— everybody . [ 1 out of every 100 americans is currently behind bars ] my name is dennis . i 'm 52 years old . i 'm serving a 15-year sentence for assaulting my wife . my name is louis , 35 . i sold narcotics [ clears throat ] since i was about 13 or so . my name is juan . i 'm 34 years old . i 'm here for second degree murder . yeah . sadly , this is my charge . my name is celine . i 'm 39 . i 'll be 40 soon . i was given a life term . [ ♪ music ♪ ] a lot of times what lands people in prison [ fleet maull - prison mindfulness institute ] and what brings them back is a lack of good problem-solving skills and good communication skills . [ ♪ music ♪ ] [ richman ] fleet approached us asking if he could do some work in here . we were challenged . our union wanted to know how we could possibly bring an ex-offender in . [ maull ] i served 14½ years on a 25-year , no parole sentence . hello . [ ♪ music ♪ ] having served 14 years boosts his credibility— boosts his credibility with inmates . how 's your week been ? - it 's good . [ maull ] yeah ? good . what 's up ? yeah . hey . welcome . when i got locked up , i really hit a wall of just seeing the craziness of my life path up until then and the incredible selfish decisions i 'd been making . my son was 9 years old . he was going to grow up without his dad . and i was just so deeply full of remorse and regret that i just literally started practicing meditation like my hair was on fire . so i became extremely motivated to turn my life around . [ ♪ music ♪ ] and so i was living the life of this prison monk . [ ♪ music ♪ ] i was sourcing a meditation group twice a week in the chapel . [ ♪ music ♪ ] i started receiving letters from prisoners while i was in prison . i had published some articles ; people knew about me out in the world a little bit , and they started sending some of these letters to me thinking i would know what to do with them . i worked in the education department , and i had access to a copy machine . i would copy articles out of books , and i 'd put together a little thing and i 'd send it off to a prisoner . so it started off that way , and i decided it was a much bigger deal than i could do from my prison cells . i think we have a co-creative relationship with our life . we ca n't control other people , we do n't control life , but is there some relationship between what we put out and what comes back ? freedom before i came here was just another word . i had never been to prison before . all you know is what the media and the movies say about prison— `` take care of yourself , man . '' `` somebody 's going to try to take your manhood or something . '' you know what i mean ? i 'm thinking i 'm going to come in here and fight the world . [ maull ] in a prison like moran , there 's a serious conflict waiting around any corner . it 's an environment where people 's worst behaviors are just right there just under the surface . [ ♪ music ♪ ] when i first came in , i fought with officers , would beat up anyone , would do the unthinkable just because . [ dennis ] it 's a vicious cycle because once you come to prison your life just keeps tumbling , tumbling , tumbling , and it 's like a never-ending wall that wo n't stop building unless you find some way to get over that wall or at least in front of it . [ richman ] what circumstances did they have to survive on the street to bring them to where they are now ? do we want to save those lives , or do we want to discard them ? the crimes i committed , i brought shame to not only myself but to those who i love . so i 'm just really trying to do something to get out of that cycle . somebody 's given us an opportunity just to meditate and connect ourselves , and that 's golden . so sit up with that good posture , just rest your hands on your legs , and just take a moment to just feel . [ ♪ music ♪ ] [ richman ] i 've always thought that the people who survive are so much stronger than i could ever be . i asked fleet how he survived and thrived the way he has . he credits meditation for having given him the strength to live his life in prison and come out not as much the worse for wear as most people do . i do n't have a release date . so i can only go home when they decide i can . so i learned to live day by day , and that helped me to deal with prison , and i could only do that being in the moment , being in the now . [ ♪ music ♪ ] it 's like if i do n't like what 's going on , what can i do to shift it ? if i do n't like the relationship i have with my boss or with one of the cos or something , could i approach that person in a different way ? can i get creative about what i 'm doing to bring about a shift in the way things are— in other words , owning my own situation . so how do you resolve that ? i take a breath and then [ chuckles ] i step back . really , you have to . [ maull ] then suddenly get that there 's this whole thing there that they thought was who they are . that 's the only reality they knew . suddenly they get to step outside of that a little bit . you just see the lights go on . it 's like this sudden illumination . it 's like a mini enlightenment of sorts . and that 's very powerful . that 's what keeps me coming . the reality of it is i 'm living life , and meditation it has brought a new perspective in the way that it gave me like a tool to really look inside myself and change the way i am . [ richman ] people do n't understand the value of what they call the soft stuff , and i sometimes think without the soft stuff , no matter how much hard stuff you have , you 're bound to fail . you can live your life . you can be yourself . you can show others that this is n't a place to breed a better criminal ; this could actually be a place to breed a better person . you 're here because the way that you were did n't work . so why not be better ? [ prisoners chattering ] [ richman ] the people in prison are us . they 're not monsters . and more importantly , whether we want them to or not , they 're getting out . so do you want them to come out angrier and meaner and more dangerous than they were when they came in , or do you want to do whatever you can to change their behavior while they 're here ? we need people to see and experience prisoners stepping out of that culture and doing something transformative with their lives , and then people will start to have faith , people will see people coming back to their community and they realize these are human beings and that human beings ' lives have value and they 're not expendable . [ ♪ music ♪ ] [ this year 700,000 people will return home from prison ] [ ♪ music ♪ ] [ directed by emmanuel vaughan-lee , produced by dorothee royal-hedinger ] [ cinematography by elias koch , edited by adam loften , sound recording by emmanuel vaughan-lee ] [ music by h. scott salinas , sound mix by d. chris smith ] [ www.globalonenessproject.org ]
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i was given a life term . [ ♪ music ♪ ] a lot of times what lands people in prison [ fleet maull - prison mindfulness institute ] and what brings them back is a lack of good problem-solving skills and good communication skills . [ ♪ music ♪ ] [ richman ] fleet approached us asking if he could do some work in here .
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fleet maull says that what lands people in prison and what brings them back are the lack of ____________ and communication skills .
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i 'm changing my tie to an alkali metal tie . you have an alkali metal tie ? it 's a new tie i just got . this one 's a dutch one . i was given it on saturday so here you can see we have the alkali metals ( and where are they ? ) here . and the alkali metals are very reactive . so , we 've seen that lithium does n't react very much but then as you go to sodium and then to potassium and rubidium the violence of the reaction gets more and more and more . in cesium it 's even greater . i do n't know wether the people making this tie were so frightened that they did n't put it on . but in each of these cases the reaction is removing one electron after another , one electron from the outer shell of the atom , and the bigger the atom , the easier it is to remove the electron . and as you go down the periodic table , the size of the atom increases so it 's easier to remove the electron . so francium would almost certainly be even bigger than cesium , because it 's a whole row lower down . and so , that should react with water with enormous violence . but , unfortunately , francium is very radioactive and you ca n't get a nice lump of francium the sort of size that you 'd like to throw in water to make the youtube video of the century . francium was named after france , was discovered by one of madame curie 's pupils in 1939 , five years after madame curie herself died . i always thought it was madame curie herself that discovered it but in fact it was discovered after her death . but its properties would probably be similar to those of cesium if it was not very radioactive . but radioactivity like that makes it very difficult for chemists to study the chemistry in enormous detail . chemical reactions are really quite sensitive to temperature and radioactive materials , as they decay , give out energy so the compounds themselves tend to heat up . a lump of plutonium , which is very radioactive , is really quite warm to touch . and francium , which i think is more radioactive , is probably very warm . so i think the melting point of francium will be lower than that of cesium because the melting points go down the group , and because it will be generating heat , almost certainly francium will be liquid at room temperature . but i 've never seen it . it might well be colored , as well , because cesium is golden colored so i would not be surprised if francium was red . but i have no idea . and i 'm not sure if anybody knows . . . . . . . . . . . . . captions by www.subply.com
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and so , that should react with water with enormous violence . but , unfortunately , francium is very radioactive and you ca n't get a nice lump of francium the sort of size that you 'd like to throw in water to make the youtube video of the century . francium was named after france , was discovered by one of madame curie 's pupils in 1939 , five years after madame curie herself died . i always thought it was madame curie herself that discovered it but in fact it was discovered after her death . but its properties would probably be similar to those of cesium if it was not very radioactive .
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who discovered francium ?
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so copernicium , or copernicium as the discoverers would prefer it to be pronounced , is the latest name to go up on the periodic table and it is really very exciting because it is the first time in as many years that a new name has appeared . and not only has it appeared but quite excitingly , it has appeared with a bit of controversy - what should the symbol be ? the first suggestion was that it should be called , the symbol should be cp , capital c with little p and that has got really quite an argument inorganic chemists who use organic groups in their compounds got quite excited because cp is the symbol that is used for cyclopentadienyl ion which binds to all sorts of different metals and then it was discovered or realised that , many , many years ago , cp was used as an alternative symbol for element number 71 , lutetium , which in some countries we called cassiopeium . and i ’ ve looked in lots and lots of books that i have got at home and i can ’ t find one of them that uses this name , but the reason why it is important is because now more and more old papers , old books are being digitised on the internet , if you start searching for the symbol cp it will start throwing up old papers and cause confusion . so the decision has been made by the international union of pure and applied chemistry or the recommendation is that the symbol should be cn , capital c , little n. and i think that this is a very sensible suggestion because it is unlikely that it can be confused with cyanide which is capital c , capital n. and it is also nice for our chinese colleagues because cn is the domain name for chinese websites and i think most chemists will be very happy with that . the element itself was first made quite a few years ago , and it ’ s made like all these heavy elements by taking the nuclei of two atoms that are lighter and banging them together and if you are aiming for element 112 then you need to take 2 nuclei , which have atomic numbers which when you add them together come up to 112 , so in this case you take lead which is atomic number 82 and so to get from 82 to 112 you need to add 30 , so you accelerate zinc atoms which have atomic number of 30 towards these in a high speed accelerator and every so often , and quite rarely , these two nuclei fuse together to give you an element or an atom of element 112 . when you make the atom , it exists , for a short time which might be a thousandth of a second , or a few thousandths of a second or it might be as long as half a second or even a second . and then the nucleus of the atom starts to decay . now it doesn ’ t blow into parts which are just protons and neutrons in one great whoosh ! but instead it starts going down by steps , usually the atomic number changes by two units or one unit depending what sort of particle is ejected from the nucleus . so in the case of 112 , and i don ’ t know the details yet , it will decay . for example , the first step may be going from 112 to 110 then the second step may be just one unit to 109 , and then two down to 107 and so on . until you get to an element below the mass of uranium the mass of 92 - which is stable .
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and not only has it appeared but quite excitingly , it has appeared with a bit of controversy - what should the symbol be ? the first suggestion was that it should be called , the symbol should be cp , capital c with little p and that has got really quite an argument inorganic chemists who use organic groups in their compounds got quite excited because cp is the symbol that is used for cyclopentadienyl ion which binds to all sorts of different metals and then it was discovered or realised that , many , many years ago , cp was used as an alternative symbol for element number 71 , lutetium , which in some countries we called cassiopeium . and i ’ ve looked in lots and lots of books that i have got at home and i can ’ t find one of them that uses this name , but the reason why it is important is because now more and more old papers , old books are being digitised on the internet , if you start searching for the symbol cp it will start throwing up old papers and cause confusion .
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as the professor explained , cp was used as an alternative symbol for the element lutetium . what was the alternate name for this element used in some countries before 1950 ?
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testing , testing , one , two , three . when your band is trying to perform , feedback is an annoying obstacle , but in the grand orchestra of nature , feedback is not only beneficial , it 's what makes everything work . what exactly is feedback ? the key element , whether in sound , the environment or social science , is a phenomenon called mutual causal interaction , where x affects y , y affects x , and so on , creating an ongoing process called a feedback loop . and the natural world is full of these mechanisms formed by the links between living and nonliving things that build resilience by governing the way populations and food webs respond to events . when plants die , the dead material enriches the soil with humus , a stable mass of organic matter , providing moisture and nutrients for other plants to grow . the more plants grow and die , the more humus is produced , allowing even more plants to grow , and so on . this is an example of positive feedback , an essential force in the buildup of ecosystems . but it 's not called positive feedback because it 's beneficial . rather , it is positive because it amplifies a particular effect or change from previous conditions . these positive , or amplifying , loops can also be harmful , like when removing a forest makes it vulnerable to erosion , which removes organic matter and nutrients from the earth , leaving less plants to anchor the soil , and leading to more erosion . in contrast , negative feedback diminishes or counteracts changes in an ecosystem to maintain a more stable balance . consider predators and their prey . when lynx eat snowshoe hares , they reduce their population , but this drop in the lynx 's food source will soon cause their own population to decline , reducing the predation rate and allowing the hare population to increase again . the ongoing cycle creates an up and down wavelike pattern , maintaining a long-term equilibrium and allowing a food chain to persist over time . feedback processes might seem counterintuitive because many of us are used to more predictable linear scenarios of cause and effect . for instance , it seems simple enough that spraying pesticides would help plants grow by killing pest insects , but it may trigger a host of other unexpected reactions . for example , if spraying pushes down the insect population , its predators will have less food . as their population dips , the reduced predation would allow the insect population to rise , counteracting the effects of our pesticides . note that each feedback is the product of the links in the loop . add one negative link and it will reverse the feedback force entirely , and one weak link will reduce the effect of the entire feedback considerably . lose a link , and the whole loop is broken . but this is only a simple example , since natural communities consist not of separate food chains , but networks of interactions . feedback loops will often be indirect , occurring through longer chains . a food web containing twenty populations can generate thousands of loops of up to twenty links in length . but instead of forming a disordered cacophany , feedback loops in ecological systems play together , creating regular patterns just like multiple instruments , coming together to create a complex but harmonious piece of music . wide-ranging negative feedbacks keep the positive feedbacks in check , like drums maintaining a rhythm . you can look at the way a particular ecosystem functions within its unique habitat as representing its trademark sound . ocean environments dominated by predator-prey interactions , and strong negative and positive loops stabilized by self-damping feedback , are powerful and loud , with many oscillations . desert ecosystems , where the turn over of biomass is slow , and the weak feedbacks loops through dead matter are more like a constant drone . and the tropical rainforest , with its great diversity of species , high nutrient turnover , and strong feedbacks among both living and dead matter , is like a lush panoply of sounds . despite their stabilizing effects , many of these habitats and their ecosystems develop and change over time , as do the harmonies they create . deforestation may turn lush tropics into a barren patch , like a successful ensemble breaking up after losing its star performers . but an abandoned patch of farmland may also become a forest over time , like a garage band growing into a magnificent orchestra .
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note that each feedback is the product of the links in the loop . add one negative link and it will reverse the feedback force entirely , and one weak link will reduce the effect of the entire feedback considerably . lose a link , and the whole loop is broken .
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one of the more prevalent feedback loops discussed today is one in relation to melting polar ice caps due to climate change . is this a positive or negative feedback loop ? explain your answer .
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all the material objects around you are composed of submicroscopic units we call molecules . and molecules in turn are composed of individual atoms . molecules frequently break apart and then form new molecules . on the other hand , virtually all the atoms you come in to contact with through the course of your life , the ones in the ground beneath you , the air you breath , the food you eat , those that make up every living thing , including you , have existed for billions of years and were created in places very unlike our planet . how those atoms came about is what i want to share with you . it all started 14 billion years ago with an event we call the big bang , which resulted in a universe consisting of gas alone . there were no stars and no planets . the gas was made up only of atoms belonging to the simplest elements . it was about 75 percent hydrogen and almost all the rest was helium . no elements like carbon , oxygen or nitrogen existed . no iron , silver or gold . in some places , the density of this gas was slightly higher than in others . due to gravity , those places attracted even more gas , which further strengthened the pull of gravity , which then drew more gas in , and so on . eventually , large dense gas balls formed , shrinking under their own gravity and consequently heating up on the inside . at some point , the core of such a ball gets hot enough that nuclear fusion occurs . hydrogen atoms smash together to form helium , accompanied by a great release of energy , strong enough to counteract the shrinking force of the gravity . when the energy pushing out from the fusion reactions matches the gravity pulling all the gas inwards , an equilibrium occurs . from this a star is born . over its lifetime , the fusion reactions in the core of a massive star will produce not only helium , but also carbon , oxygen , nitrogen and all the other elements in the periodic table up to iron . but eventually , the core 's fuel runs out , leaving it to collapse completely . that causes an unbelievably powerful explosion we call a supernova . now there are two things to note about how supernovas create elements . first , this explosion releases so much energy that fusion goes wild forming elements with atoms even heavier than iron like silver , gold and uranium . second , all the elements that had been accumulating in the core of the star , like carbon , oxygen , nitrogen , iron , as well as all of those formed in the supernova explosion , are ejected in to interstellar space where they mix with the gas that 's already there . history then repeats itself . gas clouds , now containing many elements besides the original hydrogen and helium , have higher density areas that attract more matter , and so on . as before , new stars result . our sun was born this way about 5 billion years ago . that means that the gas it arose from had itself been enriched with many elements from supernova explosions since the universe began . so that 's how the sun wound up with all the elements . it 's still mostly hydrogen at 71 percent , with most of the rest being helium at 27 percent . but bear in mind that while the first stars were made up of hydrogen and helium alone , the remaining elements in the periodic table make up two percent of the sun . and what about earth ? planets form as an incidental process to star formation out of the same gas cloud as the star itself . small planets like ours do n't have enough gravity to hold on to much hydrogen or helium gas since both of those are very light . so , even though carbon , nitrogen , oxygen and so on made up only two percent of the gas cloud from which earth was formed , these heavier elements form the bulk of our planet and everything on it . think about this : with the exception of hydrogen and some helium , the ground you walk on , the air you breath , you , everything is made of atoms that were created inside stars . when scientists first worked this out over the first half of the 20th century , the famous astronomer harlow shapley commented , `` we are brothers of the boulders , cousins of the clouds . ''
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no elements like carbon , oxygen or nitrogen existed . no iron , silver or gold . in some places , the density of this gas was slightly higher than in others .
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gold atoms are created ________ .
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say you 're helping plan a friend 's party , and he sends you a text asking you to `` bring bob , a dj and a clown . '' you 're pretty impressed . you had no idea bob was so multitalented . but when the day arrives , it turns out that he 's not , and you were supposed to bring three different people . as you and bob sit at the silent , clownless party , it occurs to you that the confusion could 've been avoided simply by using another comma after dj . this final comma in a list , placed directly before the main conjunction , such as and , or , or nor , is called the serial comma , or oxford comma . and it has long driven grammar nerds crazy because even major language institutions ca n't agree on whether it should be used . ironically , the oxford comma is more common in the united states , where it 's recommended by the mla , the chicago style manual , and the us government printing office , though not by the ap style book . in the uk and other english-speaking countries , most style guides do not support the comma 's use , with the exception of its namesake , the oxford university press . why not use the serial comma ? one of the main arguments is that the conjunction is usually enough to denote a separate entity . and where it 's not , like in your ill-fated invite list , changing the order of terms will usually do the job . journalists also dislike the comma because it takes up precious space and can make text look cluttered . sometimes , it can even create confusion of its own . for example , if your friend had asked for `` bob , a dj and a puppy , '' you 'd probably figure out that they 're three separate beings . puppies are cute , but they do n't make great djs . with the comma , you may think bob is the dj , and all you need is him and the puppy . the argument over the oxford comma has raised such strong passions over the years that a sort of truce has been reached . the common wisdom is that its use is optional , and depends on whether it will help to avoid confusion . for one thing , you 're supposed to keep your use or avoidance of the oxford comma consistent throughout a whole piece of writing . so , using it only where necessary is not an option . and the very idea of a grammatical rule being optional is a bit odd . imagine that you had n't messed up the party planning , and read the next day that `` everyone had a great time - ninjas , pirates , vikings , old and young . '' if the oxford comma were standard , you would notice it missing and conclude that old and young must describe the awesome guests already listed . but as things stand , you will always wonder whether it means that a bunch of regular , boring kids and old people showed up as well . ultimately , the serial comma may be useful or annoying , but your opinion on it , as for many optional things , probably has something to do with whichever style you were raised on . your high school teachers favored it ? it 's likely you 're still using it . your first editor hated it ? you probably do , too . and maybe so much hairsplitting over a tiny squiggle on a page is a bit silly . after all , there are so many bigger problems to worry about . but sometimes , little things can make a big difference .
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as you and bob sit at the silent , clownless party , it occurs to you that the confusion could 've been avoided simply by using another comma after dj . this final comma in a list , placed directly before the main conjunction , such as and , or , or nor , is called the serial comma , or oxford comma . and it has long driven grammar nerds crazy because even major language institutions ca n't agree on whether it should be used .
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which of the following institutions does not support the comma ’ s usage ?
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translator : tom carter reviewer : bedirhan cinar the most important walls in western history are n't even in the west . they surround the modern city of istanbul , constantinople as the romans called it . and for a thousand years , the fate of europe depended on them . constantinople was designed to be the center of the world . when the frontiers of the roman empire began to crumble in the 4th century , the capital was moved to the cultured , wealthy , and still stable east . there , at the crossroads between europe and asia , the hub of the major trade routes of the ancient world , the emperor constantine built his city . this was the city of libraries and universities , 20 times the size of london or paris at the time . it contained the priceless knowledge of the classical world which was fading in the west . to protect this masterpiece from its many enemies , constantine 's successors built the finest defensive fortifications ever made . the first line of protection was a moat 60 feet wide and 22 feet deep , stretching all four miles from coast to coast . pipes from inside the city could fill it at the first sight of the enemy , and a short wall protected archers who could fire at the soaked soldiers trying to swim across . those who were lucky enough to clear the moat had to contend with an unceasing barrage from the 27 foot outer wall above . arrows , spears , or far worse , greek fire -- an ancient form of napalm that would ignite on contact and could n't be extinguished by water -- would rain down on them . squads of roman defenders would carry portable flame throwers , spraying anyone trying to climb out of the moat . the terrified victims would leap back , only to find that they still burned underwater . at times , the romans would also mount siphons onto the ramparts , and launch clay pots full of greek fire from catapults at an invading army . the front lines would turn into an inferno , making it appear as if the earth itself was on fire . if , by some miracle , the outer wall was compromised , attackers would be faced with the final defense : the great inner wall . these walls were wide enough to have four men ride side by side , allowing troops to be rushed wherever they were needed . attilla the hun , destroyer of civilizations , who named himself the scourge of god , took one look at them and turned around . the avars battled the walls uselessly til their catapults ran out of rocks . the turks tried to tunnel under them , but found the foundations too solid . the arabs tried to starve the city into submission , but ran out of food themselves and had to resort to cannibalism . it took the guns of the modern world to finally bring them down . in 1453 , the turks brought their super weapon : a monster cannon that could fire a 15 hundred pound stone ball over a mile . together with more than a hundred smaller guns , they kept up a steady bombardment day and night . a section of the old walls collapsed , but even in their death throes they proved formidable . the rubble absorbed the shock of the cannonballs better than the solid wall . it took a month and a half of continuous blasting to finally open a breach . the last roman emperor , constantine the 11th , drew his sword and jumped into the gap to stop the onrushing horde , disappearing into legend . the city was taken , and the roman empire finally disappeared . but those broken walls had one last gift . as the survivors fled the doomed city , they brought with them their precious books and their ancient traditions . they traveled west to italy , reintroduced the greek language and learning to western europe , and ignited the renaissance . thanks to constantinople 's walls , that pile of brick and marble that guarded them for so long , we still have our classical past .
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and for a thousand years , the fate of europe depended on them . constantinople was designed to be the center of the world . when the frontiers of the roman empire began to crumble in the 4th century , the capital was moved to the cultured , wealthy , and still stable east .
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in what ways was constantinople ‘ designed to be the center of the world ’ ? how did constantine make sure that his new city was more prestigious than any other ?
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what do a seventeen-year-old pakistani , a norwegian explorer , a tibetan monk , and an american pastor have in common ? they were all awarded the nobel peace prize . among the top prestigious awards in the world , this prize has honored some of the most celebrated and revered international figures and organizations in history . to understand how it all got started , we have to go back to the 1800s . swedish chemist alfred nobel was then mostly known for the invention of dynamite , a breakthrough which launched his career as a successful inventor and businessman . 30 years later , he had become extremely wealthy , but never married , and had no children . when his will was opened after his death , it came as a surprise that his fortune was to be used for five prizes in physics , chemistry , medicine , literature , and peace . these prizes illustrated his lifelong commitment to sciences and his passion for literature . but what about peace ? because nobel 's name was tied to inventions used in the war industry , many have assumed that he created the peace prize out of regret . however , this is all speculation as he never expressed any such sentiments , and his inventions were also used for constructive purposes . instead , many historians connect alfred nobel 's interest for the peace cause to his decade-long friendship and correspondence with an austrian pacifist named bertha von suttner . von suttner was one of the leaders of the international peace movement , and in 1905 , after nobel 's death , she became the first woman to be awarded the nobel peace prize . nobel 's will outlined three criteria for the peace prize , which unlike the other sweden-based prizes , would be administered in norway . disarmament , peace congresses , and brotherhood between nations . these standards have since been expanded to include other ways of promoting peace , such as human rights and negotiations . and the prize does n't just have to go to one person . about a third of noble peace prizes have been shared by two or three laureates . so how do nominations for the prize work ? according to the nobel foundation , a valid nomination can come from a member of a national assembly , state government , or an international court . eligible nominators also include university rectors , professors of the social sciences , history , philosophy , law , and theology , and previous recipients of the peace prize . but if you want to know more about who was recently nominated , you 'll have to be patient . all information about nominations remains secret for 50 years . take martin luther king jr. we did n't actually know who nominated him until 2014 . his nominators turned out to be the quakers , who had won the prize previously , and eight members of the swedish parliament . there 's no limit to the number of times a person or organization can be nominated . in fact , jane addams , recognized as the founder of social work in the united states , was nominated 91 times before finally being awarded the prize . the absence of a laureate can also be symbolic . the 1948 decision not to award the prize following the death of mahatma gandhi has been interpreted as an attempt to respectfully honor the so-called missing laureate . as with the other nobel prizes , the peace prize ca n't be awarded posthumously . the secret selection process takes almost a year , and is carried out by the five appointed members of the norwegian nobel committee who are forbidden from having any official political function in norway . starting with a large pool of nominations , exceeding 300 in recent years , they access each candidate 's work and create a short list . finally , the chairman of the nobel committee publicly announces the laureate in october . the awards ceremony takes place on december 10th , the anniversary of alfred nobel 's death . the prize itself includes a gold medal inscribed with the latin words , `` pro pace et fraternitate gentium , '' or `` for the peace and brotherhood of men , '' as well as a diploma and a large cash prize . recently , it 's been 8 million swedish kronor , or roughly a million us dollars , which is split in the case of multiple laureates . and while laureates can use the prize money as they choose , in recent years , many have donated it to humanitarian or social causes . for many years , the nobel peace prize was predominately awarded to european and north american men . but in recent years , significant changes have been taking place , making the prize more global than ever . 23 organizations and 103 individuals , that 's 87 men and 16 women , have made up the 126 nobel peace prize laureates in history . they include desmond tutu for his nonviolent campaign against apartheid in south africa , jody williams for her campaign to ban and clear anti-personnel mines , rigoberta menchú tum for her work for social justice and reconciliation based on respect for the rights of indigenous peoples , martti ahtisaari for his efforts to resolve international conflicts in namibia , kosovo , and indonesia , and aung san suu kyi for her nonviolent struggle for democracy and human rights in myanmar . they 're just a few examples of the people who have inspired us , challenged us , and demonstrated through their actions that there are many paths to peace .
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what do a seventeen-year-old pakistani , a norwegian explorer , a tibetan monk , and an american pastor have in common ? they were all awarded the nobel peace prize . among the top prestigious awards in the world , this prize has honored some of the most celebrated and revered international figures and organizations in history .
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where is the nobel peace prize awarded ?
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during a long day spent roaming the forest in search of edible grains and herbs , the weary divine farmer shennong accidentally poisoned himself 72 times . but before the poisons could end his life , a leaf drifted into his mouth . he chewed on it and it revived him , and that is how we discovered tea . or so an ancient legend goes at least . tea does n't actually cure poisonings , but the story of shennong , the mythical chinese inventor of agriculture , highlights tea 's importance to ancient china . archaeological evidence suggests tea was first cultivated there as early as 6,000 years ago , or 1,500 years before the pharaohs built the great pyramids of giza . that original chinese tea plant is the same type that 's grown around the world today , yet it was originally consumed very differently . it was eaten as a vegetable or cooked with grain porridge . tea only shifted from food to drink 1,500 years ago when people realized that a combination of heat and moisture could create a complex and varied taste out of the leafy green . after hundreds of years of variations to the preparation method , the standard became to heat tea , pack it into portable cakes , grind it into powder , mix with hot water , and create a beverage called muo cha , or matcha . matcha became so popular that a distinct chinese tea culture emerged . tea was the subject of books and poetry , the favorite drink of emperors , and a medium for artists . they would draw extravagant pictures in the foam of the tea , very much like the espresso art you might see in coffee shops today . in the 9th century during the tang dynasty , a japanese monk brought the first tea plant to japan . the japanese eventually developed their own unique rituals around tea , leading to the creation of the japanese tea ceremony . and in the 14th century during the ming dynasty , the chinese emperor shifted the standard from tea pressed into cakes to loose leaf tea . at that point , china still held a virtual monopoly on the world 's tea trees , making tea one of three essential chinese export goods , along with porcelain and silk . this gave china a great deal of power and economic influence as tea drinking spread around the world . that spread began in earnest around the early 1600s when dutch traders brought tea to europe in large quantities . many credit queen catherine of braganza , a portuguese noble woman , for making tea popular with the english aristocracy when she married king charles ii in 1661 . at the time , great britain was in the midst of expanding its colonial influence and becoming the new dominant world power . and as great britain grew , interest in tea spread around the world . by 1700 , tea in europe sold for ten times the price of coffee and the plant was still only grown in china . the tea trade was so lucrative that the world 's fastest sailboat , the clipper ship , was born out of intense competition between western trading companies . all were racing to bring their tea back to europe first to maximize their profits . at first , britain paid for all this chinese tea with silver . when that proved too expensive , they suggested trading tea for another substance , opium . this triggered a public health problem within china as people became addicted to the drug . then in 1839 , a chinese official ordered his men to destroy massive british shipments of opium as a statement against britain 's influence over china . this act triggered the first opium war between the two nations . fighting raged up and down the chinese coast until 1842 when the defeated qing dynasty ceded the port of hong kong to the british and resumed trading on unfavorable terms . the war weakened china 's global standing for over a century . the british east india company also wanted to be able to grow tea themselves and further control the market . so they commissioned botanist robert fortune to steal tea from china in a covert operation . he disguised himself and took a perilous journey through china 's mountainous tea regions , eventually smuggling tea trees and experienced tea workers into darjeeling , india . from there , the plant spread further still , helping drive tea 's rapid growth as an everyday commodity . today , tea is the second most consumed beverage in the world after water , and from sugary turkish rize tea , to salty tibetan butter tea , there are almost as many ways of preparing the beverage as there are cultures on the globe .
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they would draw extravagant pictures in the foam of the tea , very much like the espresso art you might see in coffee shops today . in the 9th century during the tang dynasty , a japanese monk brought the first tea plant to japan . the japanese eventually developed their own unique rituals around tea , leading to the creation of the japanese tea ceremony .
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in what chinese dynasty was the tea plant first transported to japan ?
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carbon is a fantastically important element . there are probably , far more molecules that contain carbon , than any other element . the reason why you can get so many carbon compounds , is that carbon atoms , form chains very , very easily . sometimes millions of atoms long . if you just have atoms that will form one or two bonds then you ca n't build up huge numbers of molecules . if there 's no limit to the number of bonds you can make , you can make things that are really long . it 's like the difference between a lorry ; a truck which can pull if you 're lucky , one trailer or perhaps two and a train where you can put as many wagons or carriages as you want . so you can get really long train , so it 's just the same with carbon . so carbon it 's around us everywhere . we 're all carbon , there are lots of carbon in us , in all the hydrocarbons within our body . lots of that structures inside us and many many of the materials that we use every day . in fact the majority of us use carbon in the form of fuels every day to get to work or to go home . without carbon we could n't exist . you 're carbon , i 'm carbon , we have bones made that of calcium . but the important parts of our brains contain largely carbon . they contain nitrogen and oxygen and hydrogen as well , but carbon is the key . carbon is one of the very few elements ; that has given rise to a whole area of chemistry . organic chemistry ; the chemistry of carbon compounds , is almost a separate discipline from some of the areas of chemistry and most of the molecules that we use for plastics , for pharmaceutical products , for our food are all carbon compounds . carbon is an extremely common element but it comes in a number of different allotropes , so different forms and this one here ; this is actually some charcoal , which is just simple carbon . it 's very , very similar and very very in fresh into it to graphite . you can find lumps of carbon lying around . this is a piece here , that i found on a beach , on the northeast of england ; it 's a piece of coal . its not absolutely pure carbon , but it has a very high proportion of carbon and compared to other stones , of this sort of size , it 's really quite light more recently people have discovered diamonds , and of course graphite which is the black material that you get in pencils . people call them lead pencils but they actually contain the form of carbon called graphite so carbon comes graphite , as diamond , and also as as buckyballs or fullerenes so the carbon here which is a bit like the graphite ; it is very amorphous and it 's very very free-flowing so i 'm going to pour a little bit of carbon out onto the paper so you can see so you can see its a very light powder and you can see that it 's a very very nice , easily maneuverable and a really easy workable material . the thing that 's really exciting is that in the last 20 years people have discovered new forms of carbon ; now this is extraordinary ! people have known of carbon for thousands of years , even longer , and suddenly in the last 20 years the number of different types of carbon has grown enormously . i have a colleague who is a specialist in these new forms of carbon and i went and asked him for a model and he gave me a whole suitcase of models . let me show you . ... so , what did we get ? first of all , this is a model of graphite . the materials in the middle of pencils and it consists of layers of rings , hexagonal rings of carbon atoms . that six carbon atoms ; and they 're joined together in layers . can you see here ? there are purple bonds in between them . you can see they 're not very strong ; one is even broken here . very recently in the last 10 years its been discovered that using a piece of sellotape , you can pull off these layers ; and make single sheets of these carbon atoms . it 's called graphene . the 2-2010 nobel prize for physics , was given to two scientists for discovering graphene , there 's this structure here ; where each carbon atom is joined to 4 others , in this sort of tetrahedral pattern . tetrahedron is this group one in the middle with four rounded , and this–is diamond ; it 's really very strong . whichever way you squash it , it 's strong . you ca n't peel off layers of diamond with a piece of sellotape . diamonds are colorless ; and to understand why , you have to understand ; what gives rise to color , and the color of anything my tie , anything are caused by electrons in the molecules or material and they absorb energy and go from one level to another . in diamond , there are bonds between all the carbon atoms that use all the electrons . the electrons are very tightly bound and none of them can change their energy state , so you get no absorption . at least in the visible region of the spectrum . on the other hand with graphite , the electrons are less strongly bound . in fact it conducts electricity and it 's black because the electrons will absorb all wavelengths of visible light right from the blue to the red so that it looks black because none of the light is reflected from it . inside here we have the famous molecule , c60 like a football ( soccer ball us ) 60 carbon atoms and ray has put a little one inside here but forget that for a moment . so you can have this molecule c60 first discovered in the late 1980 's . and only isolated in the early 1990 's and there is a very similar molecule which looks a bit more squashed which is c70 . now these are also colored , but their color is rather different . have a look here . i 've got two samples one of c60 and one of c70 both of them dissolved up in the solvent toluene . so if you look here c70 is a sort of reddish brown color and c60 in the solvent has a beautiful color . i call it purple , other people call it magenta . back to the box ( suitcase ) ... and in here , we have the final form of carbon which are called nanotubes these are whole tubes ; made up of hexagons . you have two sorts one which is closed at the end and this one here which is open rather like a basket . you can put things inside it the final model is graphene this material that you can peel off graphite with a seller tape sticky tape and the reason that people get so excited is first of all this is a very thin material it 's only one atom thick and you can react the carbon atoms on here with all sorts of different molecules you can make very strong materials you can start making electronics carbon computers things like that many people believe that graphene is one of the materials of the future this is one of and raised exhibits he uses it in exhibitions to measure electrical conductivity to see if you take a piece of metal like this coin and you put the two electrodes on there you can see it conducts electricity all the lights light up and the needle goes across so he 's got different samples this one here is coal and this is graphite so there 's a track of this is a photo and this is a track of coal between two metal electrodes and you can see if we put the electrodes on here the coal does n't conduct electricity at all however if we take the graphite and do the same it conducts electricity not very well but you can see you do get some electricity going through on this other sheet he 's got a sample of c60 and here of the carbon nanotubes and you can see the c60 does n't conduct electricity either the electrons ca n't jump between one molecule and the other but when you come to the carbon nanotubes which are long molecules they conduct electricity really well not quite as well as a metal but pretty close
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so , what did we get ? first of all , this is a model of graphite . the materials in the middle of pencils and it consists of layers of rings , hexagonal rings of carbon atoms .
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why is a diamond colorless but graphite is black ?
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is teleportation possible ? could a baseball transform into something like a radio wave , travel through buildings , bounce around corners , and change back into a baseball ? oddly enough , thanks to quantum mechanics , the answer might actually be yes . sort of . here 's the trick . the baseball itself could n't be sent by radio , but all the information about it could . in quantum physics , atoms and electrons are interpreted as a collection of distinct properties , for example , position , momentum , and intrinsic spin . the values of these properties configure the particle , giving it a quantum state identity . if two electrons have the same quantum state , they 're identical . in a literal sense , our baseball is defined by a collective quantum state resulting from its many atoms . if this quantum state information could be read in boston and sent around the world , atoms for the same chemical elements could have this information imprinted on them in bangalore and be carefully directed to assemble , becoming the exact same baseball . there 's a wrinkle though . quantum states are n't so easy to measure . the uncertainty principle in quantum physics implies the position and momentum of a particle ca n't be measured at the same time . the simplest way to measure the exact position of an electron requires scattering a particle of light , a photon , from it , and collecting the light in a microscope . but that scattering changes the momentum of the electron in an unpredictable way . we lose all previous information about momentum . in a sense , quantum information is fragile . measuring the information changes it . so how can we transmit something we 're not permitted to fully read without destroying it ? the answer can be found in the strange phenomena of quantum entanglement . entanglement is an old mystery from the early days of quantum physics and it 's still not entirely understood . entangling the spin of two electrons results in an influence that transcends distance . measuring the spin of the first electron determines what spin will measure for the second , whether the two particles are a mile or a light year apart . somehow , information about the first electron 's quantum state , called a qubit of data , influences its partner without transmission across the intervening space . einstein and his colleagues called this strange communcation spooky action at a distance . while it does seem that entanglement between two particles helps transfer a qubit instantaneously across the space between them , there 's a catch . this interaction must begin locally . the two electrons must be entangled in close proximity before one of them is transported to a new site . by itself , quantum entanglement is n't teleportation . to complete the teleport , we need a digital message to help interpret the qubit at the receiving end . two bits of data created by measuring the first particle . these digital bits must be transmitted by a classical channel that 's limited by the speed of light , radio , microwaves , or perhaps fiberoptics . when we measure a particle for this digital message , we destroy its quantum information , which means the baseball must disappear from boston for it to teleport to bangalore . thanks to the uncertainty principle , teleportation transfers the information about the baseball between the two cities and never duplicates it . so in principle , we could teleport objects , even people , but at present , it seems unlikely we can measure the quantum states of the trillion trillion or more atoms in large objects and then recreate them elsewhere . the complexity of this task and the energy needed is astronomical . for now , we can reliably teleport single electrons and atoms , which may lead to super-secured data encryption for future quantum computers . the philosophical implications of quantum teleportation are subtle . a teleported object does n't exactly transport across space like tangible matter , nor does it exactly transmit across space , like intangible information . it seems to do a little of both . quantum physics gives us a strange new vision for all the matter in our universe as collections of fragile information . and quantum teleportation reveals new ways to influence this fragility . and remember , never say never . in a little over a century , mankind has advanced from an uncertain new understanding of the behavior of electrons at the atomic scale to reliably teleporting them across a room . what new technical mastery of such phenomena might we have in 1,000 , or even 10,000 years ? only time and space will tell .
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quantum states are n't so easy to measure . the uncertainty principle in quantum physics implies the position and momentum of a particle ca n't be measured at the same time . the simplest way to measure the exact position of an electron requires scattering a particle of light , a photon , from it , and collecting the light in a microscope .
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according to the uncertainty principle , which of the following observables can ’ t be simultaneously measured for a free electron :
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your rich , eccentric uncle just passed away , and you and your 99 nasty relatives have been invited to the reading of his will . he wanted to leave all of his money to you , but he knew that if he did , your relatives would pester you forever . so he is banking on the fact that he taught you everything you need to know about riddles . your uncle left the following note in his will : `` i have created a puzzle . if all 100 of you answer it together , you will share the money evenly . however , if you are the first to find the pattern and solve the problem without going through all of the leg work , you will get the entire inheritance all to yourself . good luck . '' the lawyer takes you and your 99 relatives to a secret room in the mansion that contains 100 lockers , each hiding a single word . he explains : every relative is assigned a number from 1 to 100 . heir 1 will open every locker . heir 2 will then close every second locker . heir 3 will change the status of every third locker , specifically if it 's open , she 'll close it , but if it 's closed , she 'll open it . this pattern will continue until all 100 of you have gone . the words in the lockers that remain open at the end will help you crack the code for the safe . before cousin thaddeus can even start down the line , you step forward and tell the lawyer you know which lockers will remain open . but how ? pause the video now if you want to figure it out for yourself ! answer in : 3 answer in : 2 answer in : 1 the key is realizing that the number of times a locker is touched is the same as the number of factors in the locker number . for example , in locker # 6 , person 1 will open it , person 2 will close it , person 3 will open it , and person 6 will close it . the numbers 1 , 2 , 3 , and 6 are the factors of 6 . so when a locker has an even number of factors it will remain closed , and when it has an odd number of factors , it will remain open . most of the lockers have an even number of factors , which makes sense because factors naturally pair up . in fact , the only lockers that have an odd number of factors are perfect squares because those have one factor that when multiplied by itself equals the number . for locker 9 , 1 will open it , 3 will close , and 9 will open it . 3 x 3 = 9 , but the 3 can only be counted once . therefore , every locker that is a perfect square will remain open . you know that these ten lockers are the solution , so you open them immediately and read the words inside : `` the code is the first five lockers touched only twice . '' you realize that the only lockers touched twice have to be prime numbers since each only has two factors : 1 and itself . so the code is 2-3-5-7-11 . the lawyer brings you to the safe , and you claim your inheritance . too bad your relatives were always too busy being nasty to each other to pay attention to your eccentric uncle 's riddles .
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you realize that the only lockers touched twice have to be prime numbers since each only has two factors : 1 and itself . so the code is 2-3-5-7-11 . the lawyer brings you to the safe , and you claim your inheritance .
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why is the code to the safe 2-3-5-7-11 ?
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translator : denise rq reviewer : callum downs i just want to start with a little bit of a word of warning and that is my job here tonight it 's to be a little bit of a doctor bring me down . so bear with me for a few minutes , and know that after this , things will get lighter and brighter . let 's start . i know that many of you have heard the traveler 's adage , `` take nothing but pictures , leave nothing but footprints . '' well , i 'm going to say i do n't think that 's either as benign or as simple as it sounds , particularly for those of us in industries who are portraying people in poor countries , in developing countries and portraying the poor . and those of us in those industries are reporters , researchers , and people working for ngos ; i suspect there are a lot of us in those industries in the audience . we are going overseas and bringing back pictures like these : of the utterly distressed , or the displaced , or the hungry , or the child labor , or the exotic . now susan sontag reminds us that photographs in part help define what we have the right to observe , but more importantly , they are an ethics of seeing , and i think right now , is a good time to review our ethics of seeing as our industries of reporting , and research and ngo work are collapsing and changing in part by what it 's been happening in the economy , but it 's making us forge new relationships . and those new relationships have some fuzzy boundaries . i worked at the edge of some of these fuzzy boundaries and i want to share with you some of my observations . my ethics of seeing is informed by 25 years as a reporter covering emerging economies and international relations . i believe in a free and independent press . i believe that journalism is a public good . but it 's getting harder to do that job , in part because of the massive layoffs , because the budgets for international reporting are n't there anymore , new technologies and new platforms begging new content , and there are a lot of new journalisms . there is activist journalism , humanitarian journalism , peace journalism , and we are all looking to cover the important stories of our time . so we are going to ngos and asking them if we can embed in their projects . this is in part because they are doing important work in interesting places . that 's one example here : this is a project i worked on in the blue nile in ethiopia . ngos understand the benefits of having reporters tag along on their team . they need the publicity , they are under tremendous pressure , they are competing in a very crowded market for compassion . so they are also looking to reporters and to hire freelance reporters to help them develop their public relations material and their media material . now , researchers are also under pressure . they 're under pressure to communicate their science outside of the academy . so they 're collaborating with reporters because for many researchers is difficult to write a simple story or a clear story . and the benefit for reporters is that covering field research is some of the best work out there . you not only get to cover science , but you get to meet interesting scientists , like my phd adviser revi sterling ; she 's one of the magic research high tops there . and it was in a discussion with revi that brought us to the edge of the researcher and reporter , that fuzzy boundary . and i said to her , `` i was looking forward to going to developing countries and doing research and covering stories at the same time . '' she said , `` i do n't think so , girlfriend . '' that confusion , mutual confusion , drove us to publish a paper on the conflicting ethics and the contradictory practices of research and reporting . we started with the understanding that researchers and reporters are distant cousins equally story tellers and social analysts . but we do n't see nor portray developing communities the same way . here 's a very classic example : this is somalia 1992 . it could be somalia today . and this is a standard operating procedure for much of the news video and the news pictures that you see , where a group of reporters will be trucked in , escorted to the site of a disaster , they 'll produce their material , take their pictures , get their interviews , and then they will be escorted out . this is decidedly not a research setting . sometimes , we are working on feature stories . this is an image i took of a woman in bhongir village in andhra pradesh in india . she is at a micro-finance meeting . it 's a terrific story . what is important here is that she is identifiable . you can see her face . this also is not a research picture . this is much more representative of a research picture . it 's a research site : you see young women accessing new technologies . it 's more of a time stamp , it 's a documentation of research . i could n't use this for news . it does n't tell enough , and it would n't sell . but then , the differences are even deeper than that . revi and i analyzed some of the mandates that researchers are under , they are under some very strict rules governed by their university research review boards when it comes to content and confidentiality . researchers are mandated to acquire a document of informed consent , while as a reporter , if i hang a microphone on someone , that is consent . and when it comes to creating the story , i 'll fact check as a reporter , but i do n't invite company to create that story . whereas social scientists , researchers , and particularly participatory researchers will often work on constructing the narrative with the community . and when it comes to paying for information , checkbook journalism is roundly discouraged . in part because of the bias it introduces in the kind of information you get . but social scientists understand that people 's time is valuable so they pay them for that time . while journalists are well-placed to convey the beauty of the scientific process - and i would add the ngo process - what about the words ? what happens if a research project is not particularly well designed or an ngo project does n't fulfill its goals ? or the other kind of words ; that happens after dark when the drinks happen . research environments , and reporting , trips and ngos projects are very intimate environments ; you make good friends while you are doing good work , but there is a little bit of johnnie walker journalism after dark and what happens to that line between embedded and inbedded ? what do you do with the odd and odious behavior ? the point is that you 'll want to negotiate in advance what is on the record or off the record . i will turn now to some ngo imagery which will be familiar to some of you in this audience . ( video ) for about 70 cents , you can buy a can of soda . regular or diet . in ethiopia , for just 70 cents a day , you can feed a child like jaamal nourishing meals . for about 70 cents , you can also buy a cup of coffee . in guatemala , for 70 cents a day , you can help a child like vilma get the clothes she needs to attend school . leslie dodson : there is some very common imagery that 's been around for 40 years . that 's part of sally struthers ' famine campaign . some of it is very familiar ; it 's the madonna and child . women and children are very effective in terms of ngo campaigns . we 've been looking at this imagery for a long time , for hundreds and hundreds of years ; the madonna and child . here is [ duccio ] , and here is michelangelo . my concern is : are we one noting the genders in our narratives of poverty in developing communities ? do we have women as victims and are men only the perpetrators ? the guys with the ak 47s or the boys soldiers ? because that does n't leave room for stories like : the man who is selling ice-cream at the refuge camp in southern sudan , where we did a project . or the stories of the men who are working on the bridge over the blue nile . i wonder , are these stories inconvenient to our narratives ? and what about this narrative ? this is a for profit game , and its aim is to make development fun . one question is did they inadvertently make fun of ? another set of questions is what are the rights of these children ? what rights of publicity or privacy do they have ? did they get paid ? should they get paid ? should they share their profit ? this is a for profit game . did they sign talent wavers ? i have to use these when i 'm working with ngos and documentary film makers here in the states . in the states , we take our right to privacy and publicity very seriously . so what is it about getting on a long , whole flight that makes these rights vaporize ? i do n't want to just pick on our friends in the gaming arts , i 'll turn to the graphic arts where we often see these monolithic , homogeneous stories about the great country of africa . but africa is not a country , it 's a continent . it 's 54 countries and thousands and thousands of languages . so my question is is this imagery productive ? or is it reductive ? i know that is popular . we have usaid just launched their campaign `` forward '' -- fwd : famine war and drought . and by looking at it , you 'd think that was happening all the time , all over africa , but this is about what 's happening in the horn of africa . and i 'm still trying to make sense of africa in a piece of wonder bread . i 'm wondering about that . germaine greer has wondered about the same things and she says , `` at breakfast and at dinner , we can sharpen our own appetites with a plentiful dose of the pornography of war , genocide , destitution , and disease . '' she is right . we have sharpened our appetites , but we can also sharpen our insights . it is not always war , insurrection , and disease . this is a picture out of south sudan just a couple of months before the new country was born . i will continue to work as a researcher and a reporter in developing countries , but i do it with an altered ethic of seeing : i ask myself whether my pictures are pandering , whether they contribute to stereotypes , whether the images match the message , and am i complacent , or am i complicit ? thank you ( applause )
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there is activist journalism , humanitarian journalism , peace journalism , and we are all looking to cover the important stories of our time . so we are going to ngos and asking them if we can embed in their projects . this is in part because they are doing important work in interesting places .
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according to dodson , how do ngo ’ s and researchers benefit from having reporters embed with their projects ?
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this is a kindergarten we designed in 2007 . we made this kindergarten to be a circle . it 's a kind of endless circulation on top of the roof . if you are a parent , you know that kids love to keep making circles . this is how the rooftop looks . and why did we design this ? the principal of this kindergarten said , `` no , i do n't want a handrail . '' i said , `` it 's impossible . '' but he insisted : `` how about having a net sticking out from the edge of the roof ? so that it can catch the children falling off ? '' ( laughter ) i said , `` it 's impossible . '' and of course , the government official said , `` of course you have to have a handrail . '' but we could keep that idea around the trees . there are three trees popping through . and we were allowed to call this rope as a handrail . but of course , rope has nothing to do with them . they fall into the net . and you get more , and more , more . ( laughter ) sometimes 40 children are around a tree . the boy on the branch , he loves the tree so he is eating the tree . ( laughter ) and at the time of an event , they sit on the edge . it looks so nice from underneath . monkeys in the zoo . ( laughter ) feeding time . ( laughter ) ( applause ) and we made the roof as low as possible , because we wanted to see children on top of the roof , not only underneath the roof . and if the roof is too high , you see only the ceiling . and the leg washing place -- there are many kinds of water taps . you see with the flexible tubes , you want to spray water to your friends , and the shower , and the one in front is quite normal . but if you look at this , the boy is not washing his boots , he 's putting water into his boots . ( laughter ) this kindergarten is completely open , most of the year . and there is no boundary between inside and outside . so it means basically this architecture is a roof . and also there is no boundary between classrooms . so there is no acoustic barrier at all . when you put many children in a quiet box , some of them get really nervous . but in this kindergarten , there is no reason they get nervous . because there is no boundary . and the principal says if the boy in the corner does n't want to stay in the room , we let him go . he will come back eventually , because it 's a circle , it comes back . ( laughter ) but the point is , in that kind of occasion , usually children try to hide somewhere . but here , just they leave and come back . it 's a natural process . and secondly , we consider noise very important . you know that children sleep better in noise . they do n't sleep in a quiet space . and in this kindergarten , these children show amazing concentration in class . and you know , our kind grew up in the jungle with noise . they need noise . and you know , you can talk to your friends in a noisy bar . you are not supposed to be in silence . and you know , these days we are trying to make everything under control . you know , it 's completely open . and you should know that we can go skiing in -20 degrees in winter . in summer you go swimming . the sand is 50 degrees . and also , you should know that you are waterproof . you never melt in rain . so , children are supposed to be outside . so that is how we should treat them . this is how they divide classrooms . they are supposed to help teachers . they do n't . ( laughter ) i did n't put him in . a classroom . and a washbasin . they talk to each other around the well . and there are always some trees in the classroom . a monkey trying to fish another monkey from above . ( laughter ) monkeys . ( laughter ) and each classroom has at least one skylight . and this is where santa claus comes down at the time of christmas . this is the annex building , right next to that oval-shaped kindergarten . the building is only five meters tall with seven floors . and of course , the ceiling height is very low . so you have to consider safety . so , we put our children , a daughter and a son . they tried to go in . he hit his head . he 's okay . his skull is quite strong . he is resilient . it 's my son . ( laughter ) and he is trying to see if it is safe to jump off . and then we put other children . the traffic jam is awful in tokyo , as you know . ( laughter ) the driver in front , she needs to learn how to drive . now these days , kids need a small dosage of danger . and in this kind of occasion , they learn to help each other . this is society . this is the kind of opportunity we are losing these days . now , this drawing is showing the movement of a boy between 9:10 and 9:30 . and the circumference of this building is 183 meters . so it 's not exactly small at all . and this boy did 6,000 meters in the morning . but the surprise is yet to come . the children in this kindergarten do 4,000 meters on average . and these children have the highest athletic abilities among many kindergartens . the principal says , `` i do n't train them . we leave them on top of the roof . just like sheep . '' ( laughter ) they keep running . ( laughter ) my point is do n't control them , do n't protect them too much , and they need to tumble sometimes . they need to get some injury . and that makes them learn how to live in this world . i think architecture is capable of changing this world , and people 's lives . and this is one of the attempts to change the lives of children . thank you very much . ( applause )
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this is a kindergarten we designed in 2007 . we made this kindergarten to be a circle . it 's a kind of endless circulation on top of the roof .
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according to tezuka , why did he and his team decide to make this kindergarten without any boundaries ?
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we read fiction for many reasons . to be entertained , to find out who done it , to travel to strange , new planets , to be scared , to laugh , to cry , to think , to feel , to be so absorbed that for a while we forget where we are . so , how about writing fiction ? how do you suck your readers into your stories ? with an exciting plot ? maybe . fascinating characters ? probably . beautiful language ? perhaps . `` billie 's legs are noodles . the ends of her hair are poison needles . her tongue is a bristly sponge , and her eyes are bags of bleach . '' did that description almost make you feel as queasy as billie ? we grasp that billie 's legs are n't actually noodles . to billie , they feel as limp as cooked noodles . it 's an implied comparison , a metaphor . so , why not simply write it like this ? `` billie feels nauseated and weak . '' chances are the second description was n't as vivid to you as the first . the point of fiction is to cast a spell , a momentary illusion that you are living in the world of the story . fiction engages the senses , helps us create vivid mental simulacra of the experiences the characters are having . stage and screen engage some of our senses directly . we see and hear the interactions of the characters and the setting . but with prose fiction , all you have is static symbols on a contrasting background . if you describe the story in matter of fact , non-tactile language , the spell risks being a weak one . your reader may not get much beyond interpreting the squiggles . she will understand what billie feels like , but she wo n't feel what billie feels . she 'll be reading , not immersed in the world of the story , discovering the truths of billie 's life at the same time that billie herself does . fiction plays with our senses : taste , smell , touch , hearing , sight , and the sense of motion . it also plays with our ability to abstract and make complex associations . look at the following sentence . `` the world was ghost-quiet , except for the crack of sails and the burbling of water against hull . '' the words , `` quiet , '' `` crack , '' and `` burbling , '' engage the sense of hearing . notice that buckell does n't use the generic word sound . each word he chooses evokes a particular quality of sound . then , like an artist laying on washes of color to give the sense of texture to a painting , he adds anoter layer , motion , `` the crack of sails , '' and touch , `` the burbling of water against hull . '' finally , he gives us an abstract connection by linking the word quiet with the word ghost . not `` quiet as a ghost , '' which would put a distancing layer of simile between the reader and the experience . instead , buckell creates the metaphor `` ghost-quiet '' for an implied , rather than overt , comparison . writers are always told to avoid cliches because there 's very little engagement for the reader in an overused image , such as `` red as a rose . '' but give them , `` love ... began on a beach . it began that day when jacob saw anette in her stewed-cherry dress , '' and their brains engage in the absorbing task of figuring out what a stewed-cherry dress is like . suddenly , they 're on a beach about to fall in love . they 're experiencing the story at both a visceral and a conceptual level , meeting the writer halfway in the imaginative play of creating a dynamic world of the senses . so when you write , use well-chosen words to engage sound , sight , taste , touch , smell , and movement . then create unexpected connotations among your story elements , and set your readers ' brushfire imaginations alight .
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fiction engages the senses , helps us create vivid mental simulacra of the experiences the characters are having . stage and screen engage some of our senses directly . we see and hear the interactions of the characters and the setting .
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what modes of entertainment engage our senses directly ?
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there are many stories that can be told about world war ii , from the tragic to the inspring . but perhaps one of the most heartrending experiences was that of the akune family , divided by the war against each other and against their own identities . ichiro akune and his wife yukiye immigrated to america from japan in 1918 in search of opportunity , opening a small grocery store in central california and raising nine children . but when mrs. akune died in 1933 , the children were sent to live with relatives in japan , their father following soon after . though the move was a difficult adjustment after having been born and raised in america , the oldest son , harry , formed a close bond with his grand uncle , who taught him the japanese language , culture and values . nevertheless , as soon as harry and his brother ken were old enough to work , they returned to the country they considered home , settling near los angeles . but then , december 7 , 1941 , the attack on pearl harbor . now at war with japan , the united states government did not trust the loyalty of those citizens who had family or ancestral ties to the enemy country . in 1942 , about 120,000 japanese americans living on the west coast were stripped of their civil rights and forcibly relocated to internment camps , even though most of them , like harry and ken , were nisei , american or dual citizens who had been born in the us to japanese immigrant parents . the brothers not only had very limited contact with their family in japan , but found themselves confined to a camp in a remote part of colorado . but their story took another twist when recruiters from the us army 's military intelligence service arrived at the camp looking for japanese-speaking volunteers . despite their treatment by the government , harry and ken jumped at the chance to leave the camp and prove their loyalty as american citizens . having been schooled in japan , they soon began their service , translating captured documents , interrogating japanese soldiers , and producing japanese language propaganda aimed at persuading enemy forces to surrender . the brothers ' work was invaluable to the war effort , providing vital strategic information about the size and location of japanese forces . but they still faced discrimination and mistrust from their fellow soldiers . harry recalled an instance where his combat gear was mysteriously misplaced just prior to parachuting into enemy territory , with the white officer reluctant to give him a weapon . nevertheless , both brothers continued to serve loyally through the end of the war . but harry and ken were not the only akune brothers fighting in the pacific . unbeknownst to them , two younger brothers , the third and fourth of the five akune boys , were serving dutifully in the imperial japanese navy , saburo in the naval airforce , and 15-year-old shiro as an orientation trainer for new recruits . when the war ended , harry and ken served in the allied occupational forces and were seen as traitors by the locals . when all the akune brothers gathered at a family reunion in kagoshima for the first time in a decade , it was revealed that the two pairs had fought on opposing sides . tempers flared and a fight almost broke out until their father stepped in . the brothers managed to make peace and saburo and shiro joined harry and ken in california , and later fought for the us army in korea . it took until 1988 for the us government to acknowledge the injustice of its internment camps and approve reparations payments to survivors . for harry , though , his greatest regret was not having the courage to thank his japanese grand uncle who had taught him so much . the story of the akune brothers is many things : a family divided by circumstance , the unjust treatment of japanese americans , and the personal struggle of reconciling two national identities . but it also reveals a larger story about american history : the oppression faced by immigrant groups and their perseverance in overcoming it .
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tempers flared and a fight almost broke out until their father stepped in . the brothers managed to make peace and saburo and shiro joined harry and ken in california , and later fought for the us army in korea . it took until 1988 for the us government to acknowledge the injustice of its internment camps and approve reparations payments to survivors .
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soon after the war ended , harry and ken were reunited with their father and younger brothers , saburo and shiro . saburo and shiro had fought for the imperial japanese navy during the war and when they found out harry and ken had fought for the u.s. army , they were angry and wanted to fight . their father sternly stopped the arguing and reminded the four brothers that the war was over . give reasons why you think saburo and shiro got so angry at harry and ken for fighting for the united states .
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in the early hours of august 13 , 1961 , east german construction workers flanked by soldiers and police began tearing up streets and erecting barriers throughout the city of berlin and its surroundings . this night marked the beginning of one of history 's most infamous dividing lines , the berlin wall . construction on the wall continued for the next decade as it cut through neighborhoods , separated families , and divided not just germany , but the world . to understand how we got to this point , we have to go back to world war ii . america , britain , and france joined forces with the soviet union against the axis powers . after they defeated nazi germany , each of the victorious nations occupied part of the country . the division was meant to be temporary , but the former allies found themselves at odds over their visions for post-war europe . while western powers promoted liberal market economies , the soviet union sought to surround itself with obedient communist nations , including a weakened germany . as their relations deteriorated , the federal republic of germany was formed in the west while the soviets established the german democratic republic in the east . the soviet satellite countries restricted western trade and movement , so a virtually impassable border formed . it became known as the iron curtain . in the former german capital of berlin , things were particularly complicated . although the city lay fully within the east german territory of the gdr , the post-war agreement gave the allies joint administration . so america , britain , and france created a democratic enclave in berlin 's western districts . while east germans were officially banned from leaving the country , in berlin , it was simply a matter of walking , or riding a subway , streetcar or bus , to the western half , then traveling on to west germany or beyond . this open border posed a problem for the east german leadership . they had staked a claim to represent the communist resistance against hitler and portrayed western germany as a continuation of the nazi regime . while the u.s. and its allies poured money into west germany 's reconstruction , the soviet union extracted resources from the east as war reparations , making its planned economy even less competitive . life in east germany passed under the watchful eye of the stasi , the secret police whose wiretaps and informants monitored citizens for any hint of disloyalty . while there was free health care and education in the east , the west boasted higher salaries , more consumer goods , and greater personal freedom . by 1961 , about 3.5 million people , nearly 20 % of the east german population , had left , including many young professionals . to prevent further losses , east germany decided to close the border , and that 's where the berlin wall came in . extending for 43 kilometers through berlin , and a further 112 through east germany , the initial barrier consisted of barbed wire and mesh fencing . some berliners escaped by jumping over the wire or leaving from windows , but as the wall expanded , this became more difficult . by 1965 , 106 kilometers of 3.6-meter-high concrete barricades had been added topped with a smooth pipe to prevent climbing . over the coming years , the barrier was strengthened with spike strips , guard dogs , and even landmines , along with 302 watchtowers and 20 bunkers . a parallel fence in the rear set off a 100-meter area called the death strip . there , all buildings were demolished and the ground covered with sand to provide a clear line of sight for the hundreds of guards ordered to shoot anyone attempting to cross . nevertheless , nearly 5,000 people in total managed to flee east germany between 1961 and 1989 . some were diplomats or athletes who defected while abroad , but others were ordinary citizens who dug tunnels , swam across canals , flew hot air balloons , or even crashed a stolen tank through the wall . yet the risk was great . over 138 people died while attempting escape . some shot in full view of west germans powerless to help them . the wall stabilized east germany 's economy by preventing its work force from leaving , but tarnished its reputation , becoming a global symbol of communist repression . as part of reconciliation with the east , the basic treaty of 1972 recognized east germany pragmatically while west germany retained its hope for eventual reunification . although the eastern regime gradually allowed family visits , it tried to discourage people from exercising these rights with an arduous bureaucratic process and high fees . nonetheless , it was still overwhelmed by applications . by the end of the 1980 's , the liberalization of other eastern bloc regimes caused mass demonstrations for free travel and demands for democracy . on the evening of november 9 , 1989 , east germany tried to defuse tension by making travel permits easier to obtain . but the announcement brought thousands of east berliners to the border crossing points in the wall , forcing the surprised guards to open the gates immediately . rejoicing crowds poured into west berlin as people from both sides danced atop the wall . and others began to demolish it with whatever tools they could find . although the border guards initially tried to maintain order , it was soon clear that the years of division were at an end . after four decades , germany was officially reunified in october 1990 . and the soviet union fell soon after . today , parts of the wall still stand as a reminder that any barriers we put up to impede freedom , we can also break down .
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after four decades , germany was officially reunified in october 1990 . and the soviet union fell soon after . today , parts of the wall still stand as a reminder that any barriers we put up to impede freedom , we can also break down .
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the wall fell because :
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in the third act of `` swan lake , '' the black swan pulls off a seemingly endless series of turns , bobbing up and down on one pointed foot and spinning around , and around , and around 32 times . it 's one of the toughest sequences in ballet , and for those thirty seconds or so , she 's like a human top in perpetual motion . those spectacular turns are called fouettés , which means `` whipped '' in french , describing the dancer 's incredible ability to whip around without stopping . but while we 're marveling at the fouetté , can we unravel its physics ? the dancer starts the fouetté by pushing off with her foot to generate torque . but the hard part is maintaining the rotation . as she turns , friction between her pointe shoe and the floor , and somewhat between her body and the air , reduces her momentum . so how does she keep turning ? between each turn , the dancer pauses for a split second and faces the audience . her supporting foot flattens , and then twists as it rises back onto pointe , pushing against the floor to generate a tiny amount of new torque . at the same time , her arms sweep open to help her keep her balance . the turns are most effective if her center of gravity stays constant , and a skilled dancer will be able to keep her turning axis vertical . the extended arms and torque-generating foot both help drive the fouetté . but the real secret and the reason you hardly notice the pause is that her other leg never stops moving . during her momentary pause , the dancer 's elevated leg straightens and moves from the front to the side , before it folds back into her knee . by staying in motion , that leg is storing some of the momentum of the turn . when the leg comes back in towards the body , that stored momentum gets transferred back to the dancer 's body , propelling her around as she rises back onto pointe . as the ballerina extends and retracts her leg with each turn , momentum travels back and forth between leg and body , keeping her in motion . a really good ballerina can get more than one turn out of every leg extension in one of two ways . first , she can extend her leg sooner . the longer the leg is extended , the more momentum it stores , and the more momentum it can return to the body when it 's pulled back in . more angular momentum means she can make more turns before needing to replenish what was lost to friction . the other option is for the dancer to bring her arms or leg in closer to her body once she returns to pointe . why does this work ? like every other turn in ballet , the fouetté is governed by angular momentum , which is equal to the dancer 's angular velocity times her rotational inertia . and except for what 's lost to friction , that angular momentum has to stay constant while the dancer is on pointe . that 's called conservation of angular momentum . now , rotational inertia can be thought of as a body 's resistance to rotational motion . it increases when more mass is distributed further from the axis of rotation , and decreases when the mass is distributed closer to the axis of rotation . so as she brings her arms closer to her body , her rotational inertia shrinks . in order to conserve angular momentum , her angular velocity , the speed of her turn , has to increase , allowing the same amount of stored momentum to carry her through multiple turns . you 've probably seen ice skaters do the same thing , spinning faster and faster by drawing in their arms and legs . in tchaikovsky 's ballet , the black swan is a sorceress , and her 32 captivating fouettés do seem almost supernatural . but it 's not magic that makes them possible . it 's physics .
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why does this work ? like every other turn in ballet , the fouetté is governed by angular momentum , which is equal to the dancer 's angular velocity times her rotational inertia . and except for what 's lost to friction , that angular momentum has to stay constant while the dancer is on pointe .
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a fouetté turn usually begins with a preceding turn in order to generate a :
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beneath your ribs , you 'll find , among other things , the pancreas , an organ that works a lot like a personal health coach . this organ controls your sugar levels and produces a special juice that releases the nutrients from your food to help keep you in the best possible shape . the pancreas sits just behind your stomach , an appropriate home , as one of its jobs is to break down the food you eat . it aids digestion by producing a special tonic made of water , sodium bicarbonate , and digestive enzymes . sodium bicarbonate neutralizes the stomach 's natural acidity , so these digestive enzymes can perform their jobs . lipase breaks down fatty substances , protease splits up proteins , and amylase divides carbohydrates to create energy-rich sugars . most of those nutrients then get absorbed into the blood stream , and go on to enrich the body . while all this is happening , the pancreas works on another critical task , controlling the amount of sugar in your blood . it achieves this with the hormones insulin and glucagon , which are produced in special cells called the islets of langerhans . having too much or too little sugar can be life threatening , so the pancreas must stay on constant alert . after a big meal , the blood often becomes flushed with sugar . to bring us back to normal , the pancreas releases insulin , which makes the excess sugar move into cells , where it 's either used as an energy source , or stored for later . insulin also tells the liver to shut down sugar production . on the other hand , if blood sugar is low , the pancreas releases a hormone called glucagon that tells the body 's cells and liver to release stored sugars back into the bloodstream . the interplay between insulin and glucagon is what keeps our sugar levels balanced . but a faulty pancreas can no longer coach us like this , meaning that this healthy balance is destroyed . if it 's weakened by disease , the organ 's ability to produce insulin may be reduced , or even extinguished , which can trigger the condition known as diabetes . without regular insulin release , sugar steadily builds up in the blood , eventually hardening the blood vessels and causing heart attacks , kidney failure , and strokes . the same lack of insulin deprives cells of the energy-rich sugar they need to grow and function . people with diabetes also tend to have higher levels of glucagon , which makes even more sugar circulate . without this internal health coach , our sugar levels would go haywire , and we would n't be able to digest important nutrients . but like any coach , it 's not the pancreas ' job alone to keep us healthy . it needs our conscious participation , too .
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on the other hand , if blood sugar is low , the pancreas releases a hormone called glucagon that tells the body 's cells and liver to release stored sugars back into the bloodstream . the interplay between insulin and glucagon is what keeps our sugar levels balanced . but a faulty pancreas can no longer coach us like this , meaning that this healthy balance is destroyed .
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insulin and glucagon are responsible for :
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say two people are walking down the street , and they bump into each other . they 'll just shake it off and walk on . sometimes that happens with molecules too . they just bounce off each other , and that 's that . but what if two people were to bump into each other , and during that collision , one person 's arm got severed and reattached to the other person 's face ? now that sounds really weird , but it 's similar to one of the many ways that molecules can react with each other . two molecules can join and become one . one can split apart and become two . molecules can switch parts . all these changes are chemical reactions , and we can see them happening around us . for example , when fireworks explode , or iron rusts , or milk goes bad , or people are born , grow old , die , and then decompose . but chemical reactions do n't just happen willy nilly ! everything has to be right . first , the molecules have to hit each other in the right orientation . and second , they have to hit each other hard enough , in other words , with enough energy . now you 're probably thinking that a reaction just happens in one direction and that 's it . sometimes that 's true . for example , things ca n't unburn or unexplode . but most reactions can happen in both directions , forward and reverse . there 's no reason that our face-arm guy ca n't bump into armless girl , reattaching that arm back to its original socket . now let 's zoom out a bit . now let 's say that you 've got a thousand people on the street , and all of them start with their limbs normally attached . at the beginning , every collision is a chance for person a to transfer an arm to person b 's face . and so at the beginning , more and more people end up with arms attached to their faces or arms missing . but as the number of people with arm-faces and missing arms grows , collisions between those people become more likely . and when they bump into each other , guess what ? normal-appendage people are reproduced . now the number of limb transfers per second forward will start high and then fall , and the number of limb transfers per second backward will start at zero and then rise . eventually they 'll meet , they 'll be the same . and when that happens , the number of people in each state stops changing , even though people are still bumping into each other and exchanging limbs . now how many people do you think there are in each state ? half and half , right ? no , well , maybe . it depends . it could be 50/50 , but it could be 60/40 or 15/85 , or anything . we chemists have to get our little , gloved hands dirty - ah , well , we 're in a lab so not really dirty - to figure out what the actual distribution of molecules is . even though each of limb transfers is a pretty dramatic event for the people involved , if we zoom out , we see population numbers that do n't change . we call this nirvana equilibrium , and it does n't just happen with chemical reactions . things like gene pools and highway traffic show the same pattern . it looks pretty still from 30,000 feet , but there is lots of crazy stuff happening on the ground , you just need to zoom in to see it .
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now that sounds really weird , but it 's similar to one of the many ways that molecules can react with each other . two molecules can join and become one . one can split apart and become two .
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look at the first four collisions in the video . in collision a , two people bump into each other . in collision b , two molecules ( the large one is ethene , the small one is hydrogen ) bump into each other . in collision c , the same two people bump into each other ; and in collision d , the same two molecules bump into each other . in collisions a and b , no reaction happens . in collisions c and d , reactions do happen . look closely at the four collisions and give two reasons why reactions happen in cases c and d but not in cases a and b .
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you and a fellow castaway are stranded on a desert island playing dice for the last banana . you 've agreed on these rules : you 'll roll two dice , and if the biggest number is one , two , three or four , player one wins . if the biggest number is five or six , player two wins . let 's try twice more . here , player one wins , and here it 's player two . so who do you want to be ? at first glance , it may seem like player one has the advantage since she 'll win if any one of four numbers is the highest , but actually , player two has an approximately 56 % chance of winning each match . one way to see that is to list all the possible combinations you could get by rolling two dice , and then count up the ones that each player wins . these are the possibilities for the yellow die . these are the possibilities for the blue die . each cell in the chart shows a possible combination when you roll both dice . if you roll a four and then a five , we 'll mark a player two victory in this cell . a three and a one gives player one a victory here . there are 36 possible combinations , each with exactly the same chance of happening . mathematicians call these equiprobable events . now we can see why the first glance was wrong . even though player one has four winning numbers , and player two only has two , the chance of each number being the greatest is not the same . there is only a one in 36 chance that one will be the highest number . but there 's an 11 in 36 chance that six will be the highest . so if any of these combinations are rolled , player one will win . and if any of these combinations are rolled , player two will win . out of the 36 possible combinations , 16 give the victory to player one , and 20 give player two the win . you could think about it this way , too . the only way player one can win is if both dice show a one , two , three or four . a five or six would mean a win for player two . the chance of one die showing one , two , three or four is four out of six . the result of each die roll is independent from the other . and you can calculate the joint probability of independent events by multiplying their probabilities . so the chance of getting a one , two , three or four on both dice is 4/6 times 4/6 , or 16/36 . because someone has to win , the chance of player two winning is 36/36 minus 16/36 , or 20/36 . those are the exact same probabilities we got by making our table . but this does n't mean that player two will win , or even that if you played 36 games as player two , you 'd win 20 of them . that 's why events like dice rolling are called random . even though you can calculate the theoretical probability of each outcome , you might not get the expected results if you examine just a few events . but if you repeat those random events many , many , many times , the frequency of a specific outcome , like a player two win , will approach its theoretical probability , that value we got by writing down all the possibilities and counting up the ones for each outcome . so , if you sat on that desert island playing dice forever , player two would eventually win 56 % of the games , and player one would win 44 % . but by then , of course , the banana would be long gone .
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out of the 36 possible combinations , 16 give the victory to player one , and 20 give player two the win . you could think about it this way , too . the only way player one can win is if both dice show a one , two , three or four .
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you can simulate some matches of this game at the following website : http : //scratch.mit.edu/projects/45073190/ . after simulating a few matches , who do you think has an advantage in this game ? why ?
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to many , one of the coolest things about `` game of thrones '' is that the inhabitants of the dothraki sea have their own real language . and dothraki came hot on the heels of the real language that the na'vi speak in `` avatar , '' which , surely , the na'vi needed when the klingons in `` star trek '' have had their own whole language since 1979 . and let 's not forget the elvish languages in j.r.r . tolkien 's `` lord of the rings '' trilogy , especially since that was the official grandfather of the fantasy conlangs . `` conlang '' is short for `` constructed language . '' they 're more than codes like pig latin , and they 're not just collections of fabricated slang like the nadsat lingo that the teen hoodlums in `` a clockwork orange '' speak , where `` droog '' from russian happens to mean `` friend . '' what makes conlangs real languages is n't the number of words they have . it helps , of course , to have a lot of words . dothraki has thousands of words . na'vi started with 1,500 words . fans on websites have steadily created more . but we can see the difference between vocabulary alone and what makes a real language from a look at how tolkien put together grand old elvish , a conlang with several thousands words . after all , you could memorize 5,000 words of russian and still be barely able to construct a sentence . a four-year-old would talk rings around you . that 's because you have to know how to put the words together . that is , a real language has grammar . elvish does . in english , to make a verb past , you add an `` -ed . '' wash , washed . in elvish , `` wash '' is `` allu '' and `` washed '' is `` allune . '' real languages also change over time . there 's no such thing as a language that 's the same today as it was a thousand years ago . as people speak , they drift into new habits , shed old ones , make mistakes , and get creative . today , one says , `` give us today our daily bread . '' in old english , they said , `` urne gedaeghwamlican hlaf syle us todaeg . '' things change in conlangs , too . tolkien charted out ancient and newer versions of elvish . when the first elves awoke at cuiviénen , in their new language , the word for `` people '' was `` kwendi , '' but in the language of one of the groups that moved away , teleri , over time , `` kwendi '' became `` pendi , '' with the `` k '' turning into a `` p. '' and just like real languages , conlangs like elvish split off into many . when the romans transplanted latin across europe , french , spanish , and italian were born . when groups move to different places , over time , their ways of speaking grow apart , just like everything else about them . thus , latin 's word for hand was `` manus , '' but in french , it became `` main , '' while in spain it became `` mano . '' tolkien made sure elvish did the same kind of thing . while that original word `` kwendi '' became `` pendi '' among the teleri , among the avari , who spread throughout middle earth , it became `` kindi '' when the `` w '' dropped out . the elvish varieties tolkien fleshed out the most are quenya and sindarin , and their words are different in the same way french and spanish are . quenya has `` suc '' for `` drink , '' sindarin has `` sog . '' and as you know , real languages are messy . that 's because they change , and change has a way of working against order , just like in a living room or on a bookshelf . real languages are never perfectly logical . that 's why tolkien made sure that elvish had plenty of exceptions . lots of verbs are conjugated in ways you just have to know . take even the word `` know . '' in the past , it 's `` knew , '' which is n't explained by any of the rules in english . oh well . in elvish , `` know '' is `` ista , '' but `` knew '' is `` sinte . '' oh well . the truth is , though , that elvish is more a sketch for a real language than a whole one . for tolkien , elvish was a hobby rather than an attempt to create something people could actually speak . much of the elvish the characters in the `` lord of the rings '' movies speak has been made up since tolkien by dedicated fans of elvish based on guesses as to what tolkien would have constructed . that 's the best we can do for elvish because there are no actual elves around to speak it for us . but the modern conlangs go further . dothraki , na'vi , and klingon are developed enough that you can actually speak them . here 's a translation of `` hamlet '' into klingon , although performing it would mean getting used to pronouncing `` k '' with your uvula , that weird , cartoony thing hanging in the back of your throat . believe it or not , you actually do that in plenty of languages around the world , like eskimo ones . pronouncing elvish is much easier , though . so , let 's take our leave for now from this introduction to conlangs in elvish and the other three conlangs discussed with a heartfelt quad-conlangual valedictory : `` a na marie ! '' `` hajas ! '' na'vi 's `` kiyevame ! '' `` qapla ! '' and `` goodbye ! ''
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in elvish , `` wash '' is `` allu '' and `` washed '' is `` allune . '' real languages also change over time . there 's no such thing as a language that 's the same today as it was a thousand years ago .
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would you rather that your artificial language did not change over time or that it evolved as people used it the way elvish was made to have done ?
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( music ) quick ! what 's common between beef burgers , baseball training and auto mufflers ? tough question . let 's ask it another way . what 's the common factor between mcdonald 's , d-bat and meineke ? you may know the answer if , along with a big mac , you 've absorbed a fragment of the romantic story of ray kroc . he 's the salesman that created what became the world 's biggest fast food chain . he did it by making a deal with a couple of men called the mcdonalds . brothers they were , owners of a small restaurant chain , and the deal was , he could use their brand name and their methods . then he invited small entrepreneurs to open mcdonald 's , that they 'd run as operators , with an ownership state . very different than the business model where mom and pop stores have full ownership , but no similar support . all the examples in my opening question are a franchise operation . kroc is sometimes credited with inventing franchising , and so is isaac singer , the sewing machine magnate . not so . the real genesis of franchising was not in stitches or beef , it was in beauty . martha matilda harper was a canadian-born maid . she made the beds , cleaned house , did the shopping . in the employment of a doctor 's family in ontario , she acquired a secret formula for shampoo , one more scientifically based than the quackeries advertized every day in the newspapers . the kindly doctor also taught the maturing young woman the elements of physiology . martha had a secret ambition to go along with the secret formula : a determination to run her own business . by 1888 , serving as a maid in rochester , new york , she saved enough money -- 360 dollars -- to think of opening a public hairdressing salon . but before she could realize her dream , two blows fell . she became sick , and collapsed from exhaustion . mrs. helen smith , a healing practitioner of the christian science faith , was summoned to her bedside . the two women prayed , and martha recovered . no sooner was she better then she was told , `` oh no , you ca n't rent the place you 've eyed . '' you see , her venture was to be the first public hairdressing salon . a woman in business was shocking enough then . only 17 percent of the workforce in 1890 was female , but a woman carrying out hairdressing and skincare in a public place ? why , it was sure to invite a scandal . martha spent some of her savings on a lawyer , and won her case . she proudly displayed on the door of her new her salon a photograph of the barely five-foot martha as rapunzel , with hair down to her feet , but glowing with good health . her sickness , too , had proved a boon . her ambition was now propelled by christian science values . the harper method , as she came to call her services , was as much about servicing the soul as it was about cutting hair . in the therapeutic serenity of her salon , she taught that every person could glow with the kind of beauty she had , if spiritually whole and physically obedient to what she called `` the laws of cleanliness , nourishment , exercise and breathing . '' she was very practical about it . she even designed the first reclining shampoo chair , though she neglected to patent the invention . martha 's salon was a huge success . celebrities came from out of town to experience the harper method . they enjoyed the service so much that they urged her to set up a salon in their cities . and this is where martha 's ethical sense inspired her crowning innovation . instead of commissioning agents , as other innovators had done , from 1891 , she installed working-class women just like herself in salons exactly like hers , dedicated to her philosophy and her products . but these new employees were not provided a salary by martha . the women in what became a satellite network of 500 salons in america , and then europe and central america and asia , actually owned the harper 's salons . what was good enough in the nineteenth century for suffragette campaigners like susan b. anthony and was good enough in the twentieth century for woodrow wilson , calvin and grace coolidge , jacqueline kennedy , helen hayes and ladybird johnson must be good enough for the rest of the world . today , only the harper method founder 's shop remains in rochester , new york , but martha 's legacy is manifold . her health and beauty treatments have been copied , and her business model is dominant . in fact , half of retail sales in america are through martha harper 's franchising idea . so the next time you enjoy a mcdonald 's hamburger or a good night 's rest at a days inn , think of martha . because these franchises might not be the same without her inventing the model , over a century ago .
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all the examples in my opening question are a franchise operation . kroc is sometimes credited with inventing franchising , and so is isaac singer , the sewing machine magnate . not so .
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who is commonly credited with inventing franchising ?
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jean-paul sartre made thinking and philosophy glamorous . he was born in paris in 1905 . his father , a navy captain , died when he was a baby – and he grew up extremely close to his mother until she remarried , much to his regret , when he was twelve . sartre spent most of his life in paris , where he often went to cafes on the left bank . he had a strabismus , a wandering eye , and wore distinctive , heavy glasses . he was very short ( five feet three inches ) and frequently described himself as ugly . by the 60 ’ s sartre was a household name in both europe and the united states , and so was his chosen philosophy , existentialism . sartre is famous principally for his book being and nothingness ( 1943 ) , which enhanced his reputation not so much because people could understand his ideas but because they could n't quite . existentialism was built around a number of key insights : one : things are weirder than we think sartre is acutely attentive to moments when the world reveals itself as far stranger and more uncanny than we normally admit ; moments when the logic we ascribe to it day-to-day becomes unavailable , showing things to be highly contingent and even absurd and frightening . sartre ’ s first novel – nausea , published in 1938 – is full of evocations of such moments . at one point , the hero , roquentin , a 30-year-old writer living in a fictional french seaside town , is on a tram . he puts his hand on the seat , but then pulls it back rapidly . instead of being the most basic and obvious piece of design , scarcely worth a moment ’ s notice , the seat promptly strikes him as deeply strange ; the word ‘ seat ’ comes loose from its moorings , the object it refers to shines forth in all its primordial oddity , as if he ’ s never seen one before . roquentin has to force himself to remember that this thing beside him is something for people to sit on . for a terrifying moment , roquentin has peered into what sartre calls the ‘ absurdity of the world. ’ such a moment goes to the heart of sartre ’ s philosophy . to be sartrean is to be aware of existence as it is when it has been stripped of any of the prejudices and stabilising assumptions lent to us by our day-to-day routines . we can try out a sartrean perspective on many aspects of our own lives . think of what you know as ‘ the evening meal with your partner ’ . under such a description , it all seems fairly logical , but a sartrean would strip away the surface normality to show the radical strangeness lurking beneath . dinner really means that : when your part of the planet has spun away from the energy of a distant hydrogen and helium explosion , you slide your knees under strips of a chopped-up tree and put sections of dead animals and plants in your mouth and chew , while next to you , another mammal whose genitals you sometimes touch is doing the same . two : we are free such weird moments are certainly disorienting and rather scary , but sartre wants to draw our attention to them for one central reason : because of their liberating dimensions . life is a lot odder than we think , but it ’ s also as a consequence far richer in possibilities . things don ’ t have to be quite the way they are . in the course of fully realising our freedom , we will come up against what sartre calls the ‘ angoisse ’ or ‘ anguish ’ of existence . everything is ( terrifyingly ) possible because nothing has any pre-ordained , god-given sense or purpose . humans are just making it up as they go along , and are free to cast aside the shackles at any moment . three : we shouldn ’ t live in ‘ bad faith ’ sartre gave a term to the phenomenon of living without taking freedom properly on board . he called it bad faith . we are in bad faith whenever we tell ourselves that things have to be a certain way and shut our eyes to other options . it is bad faith to insist that we have to do a particular kind of work or live with a specific person or make our home in a given place . the most famous description of ‘ bad faith ’ comes in being and nothingness , when sartre notices a waiter who strikes him as overly devoted to his role , as if he were first and foremost a waiter rather than a free human being . his movement is quick and forward , a little too precise , a little too rapid . he comes towards the patrons with a step that is a little too quick . he bends forward a little too eagerly : his voice , his eyes express an interest a little too solicitous for the order of the customer… ’ the man ( he was probably modelled on someone in saint-germain ’ s café de flore ) has convinced himself that he is essentially , necessarily a waiter rather than a free creature who could be a jazz pianist or a fisherman on a north sea trawler . four : we 're free to dismantle capitalism . the one factor that most discourages people from experiencing themselves as free is money . most of us will shut down a range of possible options ( moving abroad , trying out a new career , leaving a partner ) by saying , ‘ that ’ s if i didn ’ t have to worry about money . ' this passivity in the face of money enraged sartre at a political level . he thought of capitalism as a giant machine designed to create a sense of necessity which doesn ’ t in fact exist in reality : it makes us tell ourselves we have to work a certain number of hours , buy a particular product or service , and so on . but in this , there is only the denial of freedom – and a refusal to take as seriously as we should the possibility of living in other ways . it was because of these views that sartre had a life long interest in marxism . marxism seemed in theory to allow people to explore their freedom , by reducing the role played in their lives by material considerations . sartre took part in many protests in the streets of paris in the 60s . arrested yet again in 1968 , president charles de gaulle had him pardoned , saying , “ you don ’ t arrest voltaire. ” sartre also visited fidel castro and che guevara and admired them both deeply . as a result of these connections and his radical politics , the fbi kept a large file on sartre trying to deduce what his suspicious philosophy might really mean . sartre is inspiring in his insistence that things do not have to be the way they are . he is hugely alive to our unfulfilled potential , as individuals and as a species . he urges us to accept the fluidity of existence and to create new institutions , habits , outlooks and ideas . the admission that life doesn ’ t have some preordained logic and is not inherently meaningful can be a source of immense relief when we feel oppressed by the weight of tradition and the status quo .
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roquentin has to force himself to remember that this thing beside him is something for people to sit on . for a terrifying moment , roquentin has peered into what sartre calls the ‘ absurdity of the world. ’ such a moment goes to the heart of sartre ’ s philosophy . to be sartrean is to be aware of existence as it is when it has been stripped of any of the prejudices and stabilising assumptions lent to us by our day-to-day routines .
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sartre asserted that the world is _______ than we think .
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when reverend jim jones founded the peoples temple in 1955 , few could have imagined its horrifying end . this progressive religious movement rose in popularity and gained support from some of san francisco 's most prominent politicians . but in 1977 , amidst revelations of brainwashing and abuse , jones moved with several hundred followers to establish the commune of jonestown in guyana . billed as a utopian paradise , the colony was more like a prison camp , and when a congressional delegation arrived to investigate its conditions , jones executed his final plan . on november 18 , 1978 , 909 men , women , and children died after being forced to drink poisoned flavor aid . that grizzly image has since been immortalized as shorthand slang for single-minded cult-like thinking , `` they drank the kool-aid . '' today , there are thousands of cults around the world . it 's important to note two things about them . first , not all cults are religious . some are political , therapy-based , focused on self-improvement , or otherwise . and on the flip side , not all new religions are what we 're referring to as cults . so what exactly defines our modern understanding of cults , and why do people join them ? broadly speaking , a cult is a group or movement with a shared commitment to a usually extreme ideology that 's typically embodied in a charismatic leader . and while few turn out as deadly as jonestown or heaven 's gate , which ended in a mass suicide of 39 people in 1997 , most cults share some basic characteristics . a typical cult requires a high level of commitment from its members and maintains a strict hierarchy , separating unsuspecting supporters and recruits from the inner workings . it claims to provide answers to life 's biggest questions through its doctrine , along with the required recipe for change that shapes a new member into a true believer . and most importantly , it uses both formal and informal systems of influence and control to keep members obedient , with little tolerance for internal disagreement or external scrutiny . you might wonder whether some of these descriptions might also apply to established religions . in fact , the world `` cultus '' originally described people who cultivated the worship of certain gods by performing rituals and maintaining temples . but in time , it came to mean excessive devotion . many religions began as cults , but integrated into the fabric of the larger society as they grew . a modern cult , by contrast , separates its members from others . rather than providing guidelines for members to live better lives , a cult seeks to directly control them , from personal and family relationships , to financial assets and living arrangements . cults also demand obedience to human leaders who tend to be highly persuasive people with authoritarian and narcissistic streaks motivated by money , sex , power , or all three . while a cult leader uses personal charisma to attract initial followers , further expansion works like a pyramid scheme , with early members recruiting new ones . cults are skilled at knowing whom to target , often focusing on those new to an area , or who have recently undergone some personal or professional loss . loneliness and a desire for meaning make one susceptible to friendly people offering community . the recruitment process can be subtle , sometimes taking months to establish a relationship . in fact , more than two-thirds of cult members are recruited by a friend , family member , or co-worker whose invitations are harder to refuse . once in the cult , members are subjected to multiple forms of indoctrination . some play on our natural inclination to mimic social behaviors or follow orders . other methods may be more intense using techniques of coercive persuasion involving guilt , shame , and fear . and in many cases , members may willingly submit out of desire to belong and to attain the promised rewards . the cult environment discourages critical thinking , making it hard to voice doubts when everyone around you is modeling absolute faith . the resulting internal conflict , known as cognitive dissonance , keeps you trapped , as each compromise makes it more painful to admit you 've been deceived . and though most cults do n't lead members to their death , they can still be harmful . by denying basic freedoms of thought , speech , and association , cults stunt their members ' psychological and emotional growth , a particular problem for children , who are deprived of normal developmental activities and milestones . nevertheless , many cult members eventually find a way out , whether through their own realizations , the help of family and friends , or when the cult falls apart due to external pressure or scandals . many cults may be hard to identify , and for some , their beliefs , no matter how strange , are protected under religious freedom . but when their practices involve harassment , threats , illegal activities , or abuse , the law can intervene . believing in something should not come at the cost of your family and friends , and if someone tells you to sacrifice your relationships or morality for the greater good , they 're most likely exploiting you for their own .
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in fact , more than two-thirds of cult members are recruited by a friend , family member , or co-worker whose invitations are harder to refuse . once in the cult , members are subjected to multiple forms of indoctrination . some play on our natural inclination to mimic social behaviors or follow orders .
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cult indoctrination techniques include the use of :
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it 's a common saying that elephants never forget , but these magnificent animals are more than giant walking hard drives . the more we learn about elephants , the more it appears that their impressive memory is only one aspect of an incredible intelligence that makes them some of the most social , creative , and benevolent creatures on earth . unlike many proverbs , the one about elephant memory is scientifically accurate . elephants know every member in their herd , able to recognize as many as 30 companions by sight or smell . this is a great help when migrating or encountering other potentially hostile elephants . they also remember and distinguish particular cues that signal danger and can recall important locations long after their last visit . but it 's the memories unrelated to survival that are the most fascinating . elephants remember not only their herd companions but other creatures who have made a strong impression on them . in one case , two circus elephants that had briefly performed together rejoiced when crossing paths 23 years later . this recognition is n't limited to others of their species . elephants have also recognized humans they 've bonded with after decades apart . all of this shows that elephant memory goes beyond responses to stimuli . looking inside their heads , we can see why . the elephant boasts the largest brain of any land mammal , as well as an impressive encephalization quotient . this is the size of the brain relative to what we 'd expect for an animal 's body size , and the elephant 's eq is nearly as high as a chimpanzee 's . and despite the distant relation , convergent evolution has made it remarkably similar to the human brain , with as many neurons and synapses and a highly developed hippocampus and cerebral cortex . it is the hippocampus , strongly associated with emotion , that aids recollection by encoding important experiences into long-term memories . the ability to distinguish this importance makes elephant memory a complex and adaptable faculty beyond rote memorization . it 's what allows elephants who survived a drought in their youth to recognize its warning signs in adulthood , which is why clans with older matriarchs have higher survival rates . unfortunately , it 's also what makes elephants one of the few non-human animals to suffer from post-traumatic stress disorder . the cerebral cortex , on the other hand , enables problem solving , which elephants display in many creative ways . they also tackle problems cooperatively , sometimes even outwitting the researchers and manipulating their partners . and they 've grasped basic arithmetic , keeping track of the relative amounts of fruit in two baskets after multiple changes . the rare combination of memory and problem solving can explain some of elephants ' most clever behaviors , but it does n't explain some of the things we 're just beginning to learn about their mental lives . elephants communicate using everything from body signals and vocalizations , to infrasound rumbles that can be heard kilometers away . and their understanding of syntax suggests that they have their own language and grammar . this sense of language may even go beyond simple communication . elephants create art by carefully choosing and combining different colors and elements . they can also recognize twelve distinct tones of music and recreate melodies . and yes , there is an elephant band . but perhaps the most amazing thing about elephants is a capacity even more important than cleverness : their sense of empathy , altruism , and justice . elephants are the only non-human animals to mourn their dead , performing burial rituals and returning to visit graves . they have shown concern for other species , as well . one working elephant refused to set a log down into a hole where a dog was sleeping , while elephants encountering injured humans have sometimes stood guard and gently comforted them with their trunk . on the other hand , elephant attacks on human villages have usually occurred right after massive poachings or cullings , suggesting deliberate revenge . when we consider all this evidence , along with the fact that elephants are one of the few species who can recognize themselves in a mirror , it 's hard to escape the conclusion that they are conscious , intelligent , and emotional beings . unfortunately , humanity 's treatment of elephants does not reflect this , as they continue to suffer from habitat destruction in asia , ivory poaching in africa , and mistreatment in captivity worldwide . given what we now know about elephants and what they continue to teach us about animal intelligence , it is more important than ever to ensure that what the english poet john donne described as `` nature 's great masterpiece '' does not vanish from the world 's canvas .
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this recognition is n't limited to others of their species . elephants have also recognized humans they 've bonded with after decades apart . all of this shows that elephant memory goes beyond responses to stimuli . looking inside their heads , we can see why .
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what are some ways that elephants show complex reasoning beyond learned responses ?
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[ music ] [ music ] we ’ d like to think that we walk through our lives completely conscious , free to choose whatever we like , totally completely in control . not even close . our bodies leave a lot to autopilot , which is a good thing , because imagine having to regulate your heartbeat and your breathing and your digestive system and your body temperature , all while not peeing your pants or falling down . that would be hard . many of those involuntary actions are mysterious , annoying , just plain weird . here are five of the human body ’ s strangest out of control behaviors . start typing “ why does my ” into google and the top result is an eye-opener . involuntary twitching of the muscles around the eye has a number of causes including dry eyes , caffeine , bright lights , and just like during a tough workout , from simple fatigue . it ’ s usually totally harmless and eventually goes away on its own and is a good hint that you ’ ve probably been looking at that screen enough for one day . looking at bright light can cause more than an eye twitch . in aristotle ’ s `` book of problems '' he asks “ why is it that one sneezes more after one has looked at the sun ” proving that people have been asking a lot of the same questions for a long time and that no one told aristotle that you ’ re not supposed to stare at the sun . like , ever . don ’ t do it . the so-called photic sneeze reflex , aka the autosomal cholinergic helio-ophthalmic outburst , abbreviated `` achoo '' … yes , seriously… is experienced by about 1 in 4 people , leading scientists to believe it is genetically heritable . while the exact cause hasn ’ t been pinpointed , many scientists think it ’ s due crosstalk between the optic nerve and nerve that feeds the tickling sensation in your nose . the visual cortex of sun-sneezing people is also prone to overstimulation , which might send the sneeze sensing parts of their brain haywire . have you ever been just about to go to sleep , walking through the gates to dreamland , only to have the floor pulled out from under you and you ’ re suddenly falling and then you wake up ! this frustrating sleep starts have another cool medical name , hypnagogic myoclonus . when we drift off , the areas of our brain that control motor function are inactivated in favor of those that control our sleep cycles , which is why you can dream about riding your bike without actually moving your feet . as the sleepy part of your brain fight with the awake and moving parts of your brain , the battle can spontaneously tip back in favor of the motor control side and suddenly you ’ re like… whoa , i 'm awake . sleep starts aren ’ t the only myocloni that we experience . hiccups are an uncontrollable contraction of the diaphragm muscle that we use to draw air into our lungs . about a quarter second after that muscle contracts , the vocal cords snap shut , creating the characteristic [ hic ] . scientists still aren ’ t sure what causes em , but possible explanations include hiccups being an evolutionary remnant from a few hundred million years ago when our ancestors still had to pump water over their gills . or , since hiccups mainly happen in mammals , that they started as a way for nursing infants to clear air from their stomachs . if you want to get rid of hiccups , it seems that increasing the amount of co2 in your blood can do the job , which is common remedies include drinking water , holding our breath , or breathing into a paper bag . yawning , another long , slow , involuntary form of breathing , is common throughout the animal kingdom and even happens in the womb . we know it ’ s associated with sleep and boredom , but that doesn ’ t explain why it happens , and like most human behaviors , if you stop and think about yawning long enough it starts to become a really , really weird thing to do . hippocrates believed that yawns released noxious fumes that had built up in the body , but modern medicine has shown us that usually happens on the other end of the body . we also know that about 50 % of people who observe a yawn will yawn in response , so it ’ s thought to be a social cue to synchronize biological clocks . one theory says yawns might even cool the brain slightly to make us more alert as we get bored or sleepy . even watching someone talk for extended periods of time can induce yawning , so next time you ’ re getting bored in class , tell your teacher it ’ s mother nature ’ s fault . finally , i ’ ll leave you with one bonus behavior : post-micturition convulsion syndrome , or the pee shivers . this is another behavior for which scientists haven ’ t quite shaken out all the details , but some believe its simply because we ’ re exposing sensitive areas of our body to the cold while we expel some internal warmth . they might also arise from a bit of conflict between our autonomous nervous system that ’ s usually quietly keeping all that pee inside and the part of our conscious mind that ’ s in charge of the plumbing at that moment . these weird , wild , and often twitchy behaviors may defy nice , neat explanations , and yes , sometimes they are very annoying , but in the great movie that is life , they ’ re a nice reminder of all the amazing things going on behind the scenes . here ’ s a reflex action : you click subscribe , and i ’ ll see you again next week . stay curious .
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it ’ s usually totally harmless and eventually goes away on its own and is a good hint that you ’ ve probably been looking at that screen enough for one day . looking at bright light can cause more than an eye twitch . in aristotle ’ s `` book of problems '' he asks “ why is it that one sneezes more after one has looked at the sun ” proving that people have been asking a lot of the same questions for a long time and that no one told aristotle that you ’ re not supposed to stare at the sun .
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which of the following is not a possible cause for a twitchy eye ?
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translator : andrea mcdonough reviewer : bedirhan cinar the oval office , inauguration day , rose garden signings , and secret service agents with dark sunglasses and cool wrist radios . for a moment , forget all of it . toss out everything you know about the president . now , start over . what would you do if you had to invent the president ? that was the question facing the 55 men who got together in secret to draw up the plans for a new american government in the summer of 1787 in philadelphia , in the same place where the declaration of independence had been written eleven years earlier . declaring independence had been risky business , demanding ferocious courage that put lives and fortunes in jeopardy . but , inventing a new government was no field day either , especially when it 's summer and you 're in scratchy suits , and the windows are closed because you do n't want anybody to hear what you are saying , and the air conditioning does n't work because it wo n't be invented for nearly 200 years . and , when you do n't agree on things , it gets even hotter . for the framers , the question they argued over most while writing the constitution and creating three branches of government had to do with the executive department . one man or three to do the job ? how long should he serve ? what would he really do ? who would pick him ? how to get rid of him if he 's doing a bad job or he 's a crook ? and , of course , they all meant him , and he would be a white man . the idea of a woman or an african american , for instance , holding this high office was not a glimmer in their eyes . but the framers knew they needed someone who could take charge , especially in a crisis , like an invasion or a rebellion , or negotiating treaties . congress was not very good at making such important decisions without debates and delays . but the framers thought america needed a man who was decisive and could act quickly . they called it energy and dispatch . one thing they were dead-set against : there would be no king . they had fought a war against a country with a monarch and were afraid that one man with unchecked powers , in charge of an army , could take over the country . instead , they settled on a president and laid out his powers in article 2 of the constitution . but who would choose him ? not the people , they were too liable to be misled as one framer worried . not the legislature , that would lead to cabal and factions . got it : electors , wise , informed men who have time to make a good decision . and if they did n't produce a winner , then the decision would go to one of the other branches of government , the congress . the house of representatives would step in and make the choice , which they did in 1801 and 1825 . in the long , hot summer of 1787 , compromises were made to invent the presidency , like counting slaves as 3/5 of a person , giving the president command of the army but congress the power to declare war , and unlimited four-year terms . since then , some of those compromises have been amended and the men in office have sometimes been too strong or too weak . but , if you could start from scratch , how would you redesign the oval office ?
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not the legislature , that would lead to cabal and factions . got it : electors , wise , informed men who have time to make a good decision . and if they did n't produce a winner , then the decision would go to one of the other branches of government , the congress .
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according to the narrator , the men who wrote the constitution were afraid of :
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we usually think of rhythm as an element of music , but it 's actually found everywhere in the world around us , from the ocean tides to our own heartbeats , rhythm is essentially an event repeating regularly over time . even the ticking of a clock itself is a sort of rhythm . but for musical rhythm , a steady string of repeating single beats is not enough . for that , we need at least one opposing beat with a different sound , which can be the unstressed off beat or the accented back beat . there are several ways to make these beats distinct , whether by using high and low drums , or long and short beats . which ends up being heard as the main beat is not a precise rule , but like the famous rubin 's vase , can be reversed depending on cultural perception . in standard notation , rhythm is indicated on a musical bar line , but there are other ways . remember that ticking clock ? just as its round face can trace the linear passage of time , the flow of rhythm can be traced in a circle . the continuity of a wheel can be a more intuitive way to visualize rhythm than a linear score that requires moving back and forth along the page . we can mark the beats at different positions around the circle using blue dots for main beats , orange ones for off beats , and white dots for secondary beats . here is a basic two beat rhythm with a main beat and an opposing off beat . or a three beat rhythm with a main beat , an off beat , and a secondary beat . and the spaces between each beat can be divided into further sub-beats using multiples of either two or three . layering multiple patterns using concentric wheels lets us create more complex rhythms . for example , we can combine a basic two beat rhythm with off beats to get a four beat system . this is the recognizable backbone of many genres popular around the world , from rock , country , and jazz , to reggae and cumbia . or we can combine a two beat rhythm with a three beat one . eliminating the extra main beat and rotating the inner wheel leaves us with a rhythm whose underlying feel is three-four . this is the basis of the music of whirling dervishes , as well as a broad range of latin american rhythms , such as joropo , and even bach 's famous chaconne . now if we remember rubin 's vase and hear the off beats as the main beats , this will give us a six-eight feel , as found in genres such as chacarera , and quechua , persian music and more . in an eight beat system , we have three layered circles , each rhythm played by a different instrument . we can then add an outermost layer consisting of an additive rhythmic component , reinforcing the main beat and increasing accuracy . now let 's remove everything except for this combined rhythm and the basic two beat on top . this rhythmic configuration is found as the cuban cinquillo , in the puerto rican bomba , and in northern romanian music . and rotating the outer circle 90 degrees counterclockwise gives us a pattern often found in middle eastern music , as well as brazilian choro , and argentinian tango . in all of these examples , the underlying rhythm reinforces the basic one-two , but in different ways depending on arrangement and cultural context . so it turns out that the wheel method is more than just a nifty way of visualizing complex rhythms . by freeing us from the tyranny of the bar line , we can visualize rhythm in terms of time , and a simple turn of the wheel can take us on a musical journey around the world .
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we usually think of rhythm as an element of music , but it 's actually found everywhere in the world around us , from the ocean tides to our own heartbeats , rhythm is essentially an event repeating regularly over time . even the ticking of a clock itself is a sort of rhythm . but for musical rhythm , a steady string of repeating single beats is not enough . for that , we need at least one opposing beat with a different sound , which can be the unstressed off beat or the accented back beat .
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the number of layers in a rhythm wheel usually :
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without water , a human can only survive for about 100 hours . but there 's a creature so resilient that it can go without it for decades . this one millimeter animal can survive both the hottest and coldest environments on earth , and can even withstand high levels of radiation . this is the tardigrade , and it 's one of the toughest creatures on earth , even if it does look more like a chubby , eight-legged gummy bear . most organisms need water to survive . water allows metabolism to occur , which is the process that drives all the biochemical reactions that take place in cells . but creatures like the tardigrade , also known as the water bear , get around this restriction with a process called anhydrobiosis , from the greek meaning life without water . and however extraordinary , tardigrades are n't alone . bacteria , single-celled organisms called archaea , plants , and even other animals can all survive drying up . for many tardigrades , this requires that they go through something called a tun state . they curl up into a ball , pulling their head and eight legs inside their body and wait until water returns . it 's thought that as water becomes scarce and tardigrades enter their tun state , they start synthesize special molecules , which fill the tardigrade 's cells to replace lost water by forming a matrix . components of the cells that are sensitive to dryness , like dna , proteins , and membranes , get trapped in this matrix . it 's thought that this keeps these molecules locked in position to stop them from unfolding , breaking apart , or fusing together . once the organism is rehydrated , the matrix dissolves , leaving behind undamaged , functional cells . beyond dryness , tardigrades can also tolerate other extreme stresses : being frozen , heated up past the boiling point of water , high levels of radiation , and even the vacuum of outer space . this has led to some erroneous speculation that tardigrades are extraterrestrial beings . while that 's fun to think about , scientific evidence places their origin firmly on earth where they 've evolved over time . in fact , this earthly evolution has given rise to over 1100 known species of tardigrades and there are probably many others yet to be discovered . and because tardigrades are so hardy , they exist just about everywhere . they live on every continent , including antarctica . and they 're in diverse biomes including deserts , ice sheets , the sea , fresh water , rainforests , and the highest mountain peaks . but you can find tardigrades in the most ordinary places , too , like moss or lichen found in yards , parks , and forests . all you need to find them is a little patience and a microscope . scientists are now to trying to find out whether tardigrades use the tun state , their anti-drying technique , to survive other stresses . if we can understand how they , and other creatures , stabilize their sensitive biological molecules , perhaps we could apply this knowledge to help us stabilize vaccines , or to develop stress-tolerant crops that can cope with earth 's changing climate . and by studying how tardigrades survive prolonged exposure to the vacuum of outer space , scientists can generate clues about the environmental limits of life and how to safeguard astronauts . in the process , tardigrades could even help us answer a critical question : could life survive on planets much less hospitable than our own ?
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once the organism is rehydrated , the matrix dissolves , leaving behind undamaged , functional cells . beyond dryness , tardigrades can also tolerate other extreme stresses : being frozen , heated up past the boiling point of water , high levels of radiation , and even the vacuum of outer space . this has led to some erroneous speculation that tardigrades are extraterrestrial beings .
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besides tardigrades , what other organisms can tolerate extreme environmental stresses ? do you think that they all use the same mechanisms to do this ?
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i 've always collected baseball cards . i first started playing baseball when i was eight years old , and when my hometown , red sox won the world series in 2004 , i began meeting many of the players at autograph signings and events around boston . but i noticed a few things in common . these players were n't very friendly , they were all quite overpaid and they acted more like celebrities . in middle school , a friend introduced me to a new way to collect autographs : writing the players through the mail . in doing so , i would write a letter , send a self-addressed stamped envelope , and send a few baseball cards . within a few weeks , i 'd often get a response . but it was never the modern players that would send back . it was always the players from the 50s and 60s , who were much friendlier , and much less recognized during their career . so , i continued to write letters to these retired ball players , and in 2007 , topps baseball cards came out with a set where they included a few negro league baseball player cards . negro league was a period from 1920 to the 1960s where blacks who were segregated from playing in the major leagues played in their own baseball league , often busing around the country , playing two to three games a day , under much less glamorous conditions . but over time , due to the lack of glamorization and public interest , everything just kind of faded away , leaving the history of the negro leagues behind . so , i ended up writing to these players in this set and within a few weeks , they signed my cards . from here , i began writing to negro leaguers who did n't have baseball cards . guys that were , you know , even less recognized . and in my letters , i 'd often include my phone number , and a few of them began reaching out to me . when i started speaking with them , i noticed they all had a few things in common . none of them had baseball cards , none of them had any documentation , no newspaper articles , no sorts of photos from their career , just nothing tying them to the game . and lastly , they had just left all their teammates behind . they had n't stayed in touch with any of their teammates . so , i tried to change this , and i started off by making baseball cards on my home computer . printing them out , designing them and sending them to ball players . and what i also did is i began signing up for newspaper archive websites where i 'd find old newspaper articles that would give these guys the recognition that , you know , tied them to the game . and lastly , i began becoming kind of like a private investigator , tracking down their former teammates and trying to get these guys back in touch . from here , i went on and i just spoke to these players . it got to the point where i actually had players calling me up , asking me for information . and by the time i was a freshman in high school , it was no longer a hobby at all . i had gone from an autograph collector to this negro league research obsession . i even asked for negro league autographs and stamps for christmas . so , going on through high school , i began to take this work in the negro league much more seriously . i started working with adult negro league researchers where i began working on a few different programs . the first being the negro league annual reunion in birmingham , alabama . at the reunion , we 'd have about 50 to 60 negro league ball players from around the country , and they 'd all come together , and these players would just , you know , sit in the hotel lobby for me from 8am until the late hours of the night just catching up , telling stories , and here we just had a week of events and these guys got some of this recognition and honor that they never really had before . the second program that i began working on was the negro league pension program . and the pension program was a program that was offered by major league baseball , and if you played four years in the negro league , and you can document it , these players would be entitled to 10,000 dollars a year . this meant a lot for these players . many of these guys never really did much after baseball , they did n't make much money . so , when i was able to get these players pensions , it really made a difference . when i started doing this , i encountered a lot of difficulty . i had to go through hundreds and hundreds of newspaper articles trying to find this documentation to prove they played , and in many cases i did . also i want to mention , when i was speaking with these players on the phone , tracking them down , it was n't easy either . i would go through hundreds of articles trying to look for names , find information , and i encountered quite a lot of failure . i would call people up , it would be the wrong person . it would be really awkward . i 'd also have a lot of times where i 'd call players up , and they did n't want to speak at all to me . they would hang up . when i said the word baseball , they would just refuse to talk altogether . this was because they faced a lot of segregation during their careers . along with the lack of glamorization that they faced , they also dealt with a lot of racism on and off the baseball field , which just lasted with them throughout their whole lives . these guys , you know , it was very emotional for them to talk about baseball , and it was really hard to kind of get these guys back , you know , talking about this game that they had kind of left behind . lastly though , i encountered , you know , quite a lot of success as well . some of these guys i 'd call up , i 'd talk to them for two to three hours , and these guys would just go on and on about their stories , telling me , like , exact baseball games and memories that they had . nowadays , i 've attended four negro league reunions , three of which i 've actually roomed with former negro league ball player russell `` crazy legs '' patterson of the indianapolis clowns . he actually snores at night , in case you all were wondering . i 've worked on about a dozen pensions and i 've tracked down over a hundred negro league ball players , constantly finding new ball players , getting them in touch with their former teammates , bringing baseball back into these players ' lives and bringing these guys back into the game . ( music ) thank you ! ( applause )
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the second program that i began working on was the negro league pension program . and the pension program was a program that was offered by major league baseball , and if you played four years in the negro league , and you can document it , these players would be entitled to 10,000 dollars a year . this meant a lot for these players .
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if you can prove that you played 4 years in the negro leagues , you are entitled to ________ .
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the discovery of the structure of dna was one of the most important scientific achievements in the last century , in human history , in fact . the now-famous double helix is almost synonymous with watson and crick , two of the scientists who won the nobel prize for figuring it out . but there 's another name you may know , too , rosalind franklin . you may have heard that her data supported watson and crick 's brilliant idea , or that she was a plain-dressing , belligerent scientist , which is how watson actually described her in `` the double helix . '' but thanks to franklin 's biographers , who investigated her life and interviewed many people close to her , we now know that that account is far from true , and her scientific contributions have been vastly underplayed . let 's hear the real story . rosalind elsie franklin was born in london in 1920 . she wanted to be a scientist ever since she was a teenager , which was n't a common or easy career path for girls at that time . but she excelled at science anyway . she won a scholarship to cambridge to study chemistry , where she earned her ph.d. , and she later conducted research on the structure of coal that led to better gas masks for the british during world war ii . in 1951 , she joined king 's college to use x-ray techniques to study the structure of dna , then one of the hottest topics in science . franklin upgraded the x-ray lab and got to work shining high-energy x-rays on tiny , wet crystals of dna . but the acadmemic culture at the time was n't very friendly to women , and franklin was isolated from her colleagues . she clashed with maurice wilkins , a labmate who assumed franklin had been hired as his assistant . but franklin kept working , and in 1952 , she obtained photo 51 , the most famous x-ray image of dna . just getting the image took 100 hours , the calculations necessary to analyze it would take a year . meanwhile , the american biologist james watson and the british physicist francis crick were also working on finding dna 's structure . without franklin 's knowledge , wilkins took photo 51 and showed it to watson and crick . instead of calculating the exact position of every atom , they did a quick analysis of franklin 's data and used that to build a few potential structures . eventually , they arrived at the right one . dna is made of two helicoidal strands , one opposite the other with bases in the center like rungs of a ladder . watson and crick published their model in april 1953 . meanwhile , franklin had finished her calculations , come to the same conclusion , and submitted her own manuscript . the journal published the manuscripts together , but put franklin 's last , making it look like her experiments just confirmed watson and crick 's breakthrough instead of inspiring it . but franklin had already stopped working on dna and died of cancer in 1958 , never knowing that watson and crick had seen her photographs . watson , crick , and wilkins won the nobel prize in 1962 for their work on dna . it 's often said that franklin would have been recognized by a nobel prize if only they could be awarded posthumously . and , in fact , it 's possible she could have won twice . her work on the structure of viruses led to a nobel for a colleague in 1982 . it 's time to tell the story of a brave woman who fought sexism in science , and whose work revolutionized medicine , biology , and agriculture . it 's time to honor rosalind elsie franklin , the unsung mother of the double helix .
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the now-famous double helix is almost synonymous with watson and crick , two of the scientists who won the nobel prize for figuring it out . but there 's another name you may know , too , rosalind franklin . you may have heard that her data supported watson and crick 's brilliant idea , or that she was a plain-dressing , belligerent scientist , which is how watson actually described her in `` the double helix . ''
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rosalind franklin ’ s contributions to science were exclusively in the field of biology . true or false ?
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energy is all around us , a physical quantity that follows precise natural laws . our universe has a finite amount of it ; it 's neither created nor destroyed but can take different forms , such as kinetic or potential energy , with different properties and formulas to remember . for instance , an led desk lamp 's 6 watt bulb transfers 6 joules of light energy per second . but let 's jump back up into space to look at our planet , its systems , and their energy flow . earth 's physical systems include the atmosphere , hydrosphere , lithosphere , and biosphere . energy moves in and out of these systems , and during any energy transfer between them , some is lost to the surroundings , as heat , light , sound , vibration , or movement . our planet 's energy comes from internal and external sources . geothermal energy from radioactive isotopes and rotational energy from the spinning of the earth are internal sources of energy , while the sun is the major external source , driving certain systems , like our weather and climate . sunlight warms the surface and atmosphere in varying amounts , and this causes convection , producing winds and influencing ocean currents . infrared radiation , radiating out from the warmed surface of the earth , gets trapped by greenhouse gases and further affects the energy flow . the sun is also the major source of energy for organisms . plants , algae , and cyanobacteria use sunlight to produce organic matter from carbon dioxide and water , powering the biosphere 's food chains . we release this food energy using chemical reactions , like combustion and respiration . at each level in a food chain , some energy is stored in newly made chemical structures , but most is lost to the surroundings , as heat , like your body heat , released by your digestion of food . now , as plants are eaten by primary consumers , only about 10 % of their total energy is passed on to the next level . since energy can only flow in one direction in a food chain , from producers on to consumers and decomposers , an organism that eats lower on the food chain , is more efficient than one higher up . so eating producers is the most efficient level at which an animal can get its energy , but without continual input of energy to those producers , mostly from sunlight , life on earth as we know it would cease to exist . we humans , of course , spend our energy doing a lot of things besides eating . we travel , we build , we power all sorts of technology . to do all this , we use sources like fossil fuels : coal , oil , and natural gas , which contain energy that plants captured from sunlight long ago and stored in the form of carbon . when we burn fossil fuels in power plants , we release this stored energy to generate electricity . to generate electricity , heat from burning fossil fuels is used to power turbines that rotate magnets , which , in turn , create magnetic field changes relative to a coil of wire , causing electrons to be induced to flow in the wire . modern civilization depends on our ability to keep powering that flow of electrons . fortunately , we are n't limited to burning non-renewable fossil fuels to generate electricity . electrons can also be induced to flow by direct interaction with light particles , which is how a solar cell operates . other renewable energy sources , such as wind , water , geothermal , and biofuels can also be used to generate electricity . global demand for energy is increasing , but the planet has limited energy resources to access through a complex energy infrastructure . as populations rise , alongside rates of industrialization and development , our energy decisions grow more and more important . access to energy impacts health , education , political power , and socioeconomic status . if we improve our energy efficiency , we can use our natural resources more responsibly and improve quality of life for everyone .
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other renewable energy sources , such as wind , water , geothermal , and biofuels can also be used to generate electricity . global demand for energy is increasing , but the planet has limited energy resources to access through a complex energy infrastructure . as populations rise , alongside rates of industrialization and development , our energy decisions grow more and more important . access to energy impacts health , education , political power , and socioeconomic status .
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what are some examples of energy decisions you make every day ?
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at pixar , we 're all about telling stories , but one story that has n't been told very much is the huge degree to which math is used in the production of our films . the math that you 're learning in middle school and high school is used all the time at pixar . so , let 's start with a very simple example . anybody recognize this guy ? ( cheers ) yeah , so this is woody from toy story , and let 's ask woody to , say , walk across the stage from , say , left to right , just like that . so , believe it or not , you just saw a ton of mathematics . where is it ? well , to explain that , it 's important to understand that artists and designers think in terms of shape and images but computers think in terms of numbers and equations . so , to bridge those two worlds we use a mathematical concept called coordinate geometry , right ? that is , we lay down a coordinate system with x describing how far something is to the right and y describing how high something is . so , with these coordinates we can describe where woody is at any instant in time . for instance , if we know the coordinates of the lower left corner of that image , then we know where the rest of the image is . and in that little sliding animation we saw a second ago , that motion we call translation , the x coordinate started with a value of one , and it ended with a value of about five . so , if we want to write that in mathematics , we see that the x at the end is four bigger than x at the start . so , in other words , the mathematics of translation is addition . alright ? how about scaling ? that is making something bigger or smaller . any guesses as to what the mathematics of scaling might be ? dilation , multiplication , exactly . if you 're going to make something twice as big , you need to mulitply the x and the y coordinates all by two . so , this shows us that the mathematics of scaling is mulitiplication . okay ? how about this one ? how about rotation ? alright , spinning around . the mathematics of rotation is trigonometry . so , here 's an equation that expresses that . it looks a little scary at first . you 'll probably get this in eighth or ninth grade . if you find yourselves sitting in trigonometry class wondering when you 're ever going to need this stuff , just remember that any time you see anything rotate in one of our films , there 's trigonometry at work underneath . i first fell in love with mathematics in seventh grade . any seventh graders ? a few of you ? yeah . my seventh grade science teacher showed me how to use trigonometry to compute how high the rockets that i was building was going . i just thought that was amazing , and i 've been enamored with math ever since . so , this is kind of old mathematics . mathematics that 's been known and , you know , developed by the old dead greek guys . and there 's a myth out there that all the interesting mathematics has already been figured out , in fact all of mathematics has been figured out . but the real story is that new mathematics is being created all the time . and some of it is being created at pixar . so , i 'd like to give you an example of that . so , here are some characters from some of our early films : finding nemo , monsters inc. and toy story 2 . anybody know who the blue character in the upper left is ? it 's dory . okay , that was easy . here 's a little harder one . anybody know who 's the character in the lower right ? al mcwhiggin from al 's toy barn , exactly . the thing to notice about these characters is they 're really complicated . those shapes are really complicated . in fact , the toy cleaner , i have an example , the toy cleaner there in the middle , here 's his hand . you can imagine how fun it was to bring this through airport security . his hand is a really complicated shape . it 's not just a bunch of spheres and cylinders stuck together , right ? and not only is it complicated , but it has to move in complicated ways . so , i 'd like to tell you how we do that , and to do that i need to tell you about midpoints . so , here 's a couple of points , a and b , and the line segment between them . we 're going to start out first in two dimensions . the midpoint , m , is the point that splits that line segment in the middle , right ? so , that 's the geometry . to make equations and numbers , we again introduce a coordinate system , and if we know the coordinates of a and b , we can easily compute the coordinates of m just by averaging . you now know enough to work at pixar . let me show you . so , i 'm going to do something slightly terrifying and move to a live demo here . so , what i have is a four-point polygon here , and it 's going to be my job to make a smooth curve out of this thing . and i 'm going to do it just using the idea of midpoints . so , the first thing i 'm going to do is an operation i 'll call split , which adds midpoints to all those edges . so , i went from four points to eight points , but it 's no smoother . i 'm going to make it a little bit smoother by moving all of these points from where they are now to the midpoint of their clockwise neighbor . so , let me animate that for you . i 'm going to call that the averaging step . so , now i 've got eight points , they 're a little bit smoother , my job is to make a smooth curve , so what do i do ? do it again . split and average . so , now i 've got sixteen points . i 'm going to put those two steps , split and average , together into something i 'll call subdivide , which just means split and then average . so , now i 've got 32 points . if that 's not smooth enough , i 'll do more . i 'll get 64 points . do you see a smooth curve appearing here from those original points ? and that 's how we create the shapes of our charcters . but remember , i said a moment ago it 's not enough just to know the static shape , the fixed shape . we need to animate it . and to animate these curves , the cool thing about subdivision . did you see the aliens in toy story ? you know that sound they make , `` ooh '' ? ready ? so , the way we animate these curves is simply by animating the original four points . `` ooh . '' alright , i think that 's pretty cool , and if you do n't , the door is there , it does n't get any better than that , so . this idea of splitting and averaging also holds for surfaces . so , i 'll split , and i 'll average . i 'll split , and i 'll average . put those together into subdivide , and this how we actually create the shapes of all of our surface characters in three dimensions . so , this idea of subdivision was first used in a short film in 1997 called geri 's game . and geri actually made a cameo apperance in toy story 2 as the toy cleaner . each of his hands was the first time we ever used subdivision . so , each hand was a subdivision surface , his face was a subdivision surface , so was his jacket . here 's geri 's hand before subdivision , and here 's geri 's hand after subdivision , so subdivision just goes in and smooths out all those facets , and creates the beautiful surfaces that you see on the screen and in the theaters . since that time , we 've built all of our characters this way . so , here 's merida , the lead character from brave . her dress was a subdivision surface , her hands , her face . the faces and hands of all the clansman were subdivision surfaces . today we 've seen how addition , multiplication , trigonometry and geometry play a roll in our films . given a little more time , i could show you how linear algebra , differential calculus , integral calculus also play a roll . the main thing i want you to go away with today is to just remember that all the math that you 're learning in high school and actually up through sophomore college we use all the time , everyday , at pixar . thanks .
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so , that 's the geometry . to make equations and numbers , we again introduce a coordinate system , and if we know the coordinates of a and b , we can easily compute the coordinates of m just by averaging . you now know enough to work at pixar .
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if point a has coordinates ( 1,2 ) , and the midpoint of the line segment ab has coordinates ( 5,6 ) , what are the coordinates of b ?
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imagine , for a second , a duck teaching a french class , a ping-pong match in orbit around a black hole , a dolphin balancing a pineapple . you probably have n't actually seen any of these things , but you could imagine them instantly . how does your brain produce an image of something you 've never seen ? that may not seem hard , but that 's only because we 're so used to doing it . it turns out that this is actually a complex problem that requires sophisticated coordination inside your brain . that 's because to create these new , weird images , your brain takes familiar pieces and assembles them in new ways , like a collage made from fragments of photos . the brain has to juggle a sea of thousands of electrical signals getting them all to their destination at precisely the right time . when you look at an object , thousands of neurons in your posterior cortex fire . these neurons encode various characteristics of the object : spiky , fruit , brown , green , and yellow . this synchronous firing strengthens the connections between that set of neurons , linking them together into what 's known as a neuronal ensemble , in this case the one for pineapple . in neuroscience , this is called the hebbian principle , neurons that fire together wire together . if you try to imagine a pineapple later , the whole ensemble will light up , assembling a complete mental image . dolphins are encoded by a different neuronal ensemble . in fact , every object that you 've seen is encoded by a neuronal ensemble associated with it , the neurons wired together by that synchronized firing . but this principle does n't explain the infinite number of objects that we can conjure up in our imaginations without ever seeing them . the neuronal ensemble for a dolphin balancing a pineapple does n't exist . so how come you can imagine it anyway ? one hypothesis , called the mental synthesis theory , says that , again , timing is key . if the neuronal ensembles for the dolphin and pineapple are activated at the same time , we can perceive the two separate objects as a single image . but something in your brain has to coordinate that firing . one plausible candidate is the prefrontal cortex , which is involved in all complex cognitive functions . prefrontal cortex neurons are connected to the posterior cortex by long , spindly cell extensions called neural fibers . the mental synthesis theory proposes that like a puppeteer pulling the strings , the prefrontal cortex neurons send electrical signals down these neural fibers to multiple ensembles in the posterior cortex . this activates them in unison . if the neuronal ensembles are turned on at the same time , you experience the composite image just as if you 'd actually seen it . this conscious purposeful synchronization of different neuronal ensembles by the prefrontal cortex is called mental synthesis . in order for mental sythesis to work , signals would have to arrive at both neuronal ensembles at the same time . the problem is that some neurons are much farther away from the prefrontal cortex than others . if the signals travel down both fibers at the same rate , they 'd arrive out of sync . you ca n't change the length of the connections , but your brain , especially as it develops in childhood , does have a way to change the conduction velocity . neural fibers are wrapped in a fatty substance called myelin . myelin is an insulator and speeds up the electrical signals zipping down the nerve fiber . some neural fibers have as many as 100 layers of myelin . others only have a few . and fibers with thicker layers of myelin can conduct signals 100 times faster or more than those with thinner ones . some scientists now think that this difference in myelination could be the key to uniform conduction time in the brain , and consequently , to our mental synthesis ability . a lot of this myelination happens in childhood , so from an early age , our vibrant imaginations may have a lot to do with building up brains whose carefully myelinated connections can craft creative symphonies throughout our lives .
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if the neuronal ensembles for the dolphin and pineapple are activated at the same time , we can perceive the two separate objects as a single image . but something in your brain has to coordinate that firing . one plausible candidate is the prefrontal cortex , which is involved in all complex cognitive functions .
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what is the role of myelin in the brain ?
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this is a crystal of sugar . if you press on it , it will actually generate its own electricity . how can this simple crystal act like a tiny power source ? because sugar is piezoelectric . piezoelectric materials turn mechanical stress , like pressure , sound waves , and other vibrations into electricity and vice versa . this odd phenomenon was first discovered by the physicist pierre curie and his brother jacques in 1880 . they discovered that if they compressed thin slices of certain crystals , positive and negative charges would appear on opposite faces . this difference in charge , or voltage , meant that the compressed crystal could drive current through a circuit , like a battery . and it worked the other way around , too . running electricity through these crystals made them change shape . both of these results , turning mechanical energy into electrical , and electrical energy into mechanical , were remarkable . but the discovery went uncelebrated for several decades . the first practical application was in sonar instruments used to detect german submarines during world war i. piezoelectric quartz crystals in the sonar 's transmitter vibrated when they were subjected to alternating voltage . that sent ultrasound waves through the water . measuring how long it took these waves to bounce back from an object revealed how far away it was . for the opposite transformation , converting mechanical energy to electrical , consider the lights that turn on when you clap . clapping your hands send sound vibrations through the air and causes the piezo element to bend back and forth . this creates a voltage that can drive enough current to light up the leds , though it 's conventional sources of electricity that keep them on . so what makes a material piezoelectric ? the answer depends on two factors : the materials atomic structure , and how electric charge is distributed within it . many materials are crystalline , meaning they 're made of atoms or ions arranged in an orderly three-dimensional pattern . that pattern has a building block called a unit cell that repeats over and over . in most non-piezoelectric crystalline materials , the atoms in their unit cells are distributed symmetrically around a central point . but some crystalline materials do n't possess a center of symmetry making them candidates for piezoelectricity . let 's look at quartz , a piezoelectric material made of silicon and oxygen . the oxygens have a slight negative charge and silicons have a slight positive , creating a separation of charge , or a dipole along each bond . normally , these dipoles cancel each other out , so there 's no net separation of charge in the unit cell . but if a quartz crystal is squeezed along a certain direction , the atoms shift . because of the resulting asymmetry in charge distribution , the dipoles no longer cancel each other out . the stretched cell ends up with a net negative charge on one side and a net positive on the other . this charge imbalance is repeated all the way through the material , and opposite charges collect on opposite faces of the crystal . this results in a voltage that can drive electricity through a circuit . piezoelectric materials can have different structures . but what they all have in common is unit cells which lack a center of symmetry . and the stronger the compression on piezoelectric materials , the larger the voltage generated . stretch the crystal , instead , and the voltage will switch , making current flow the other way . more materials are piezoelectric than you might think . dna , bone , and silk all have this ability to turn mechanical energy into electrical . scientists have created a variety of synthetic piezoelectric materials and found applications for them in everything from medical imaging to ink jet printers . piezoelectricity is responsible for the rhythmic oscillations of the quartz crystals that keep watches running on time , the speakers of musical birthday cards , and the spark that ignites the gas in some barbecue grill lighters when you flick the switch . and piezoelectric devices may become even more common since electricity is in high demand and mechanical energy is abundant . there are already train stations that use passengers ' footsteps to power the ticket gates and displays and a dance club where piezoelectricity helps power the lights . could basketball players running back and forth power the scoreboard ? or might walking down the street charge your electronic devices ? what 's next for piezoelectricity ?
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this results in a voltage that can drive electricity through a circuit . piezoelectric materials can have different structures . but what they all have in common is unit cells which lack a center of symmetry .
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will piezoelectric crystals respond the same way when you squish/stretch them in different directions ? or will the response vary with orientation of the crystal ?
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he was one of the most influential figures of the 20th century , forever changing the course of one of the world 's largest countries . but was he a hero who toppled an oppressive tyranny or a villain who replaced it with another ? it 's time to put lenin on the stand in history vs. lenin . `` order , order , hmm . now , was n't it your fault that the band broke up ? '' `` your honor , this is vladimir ilyich ulyanov , aka lenin , the rabblerouser who helped overthrow the russian tsar nicholas ii in 1917 and founded the soviet union , one of the worst dictatorships of the 20th century . '' `` ohh . '' `` the tsar was a bloody tyrant under whom the masses toiled in slavery . '' `` this is rubbish . serfdom had already been abolished in 1861 . '' `` and replaced by something worse . the factory bosses treated the people far worse than their former feudal landlords . and unlike the landlords , they were always there . russian workers toiled for eleven hours a day and were the lowest paid in all of europe . '' `` but tsar nicholas made laws to protect the workers . '' `` he reluctantly did the bare minimum to avert revolution , and even there , he failed . remember what happened in 1905 after his troops fired on peaceful petitioners ? '' `` yes , and the tsar ended the rebellion by introducing a constitution and an elected parliament , the duma . '' `` while retaining absolute power and dissolving them whenever he wanted . '' `` perhaps there would 've been more reforms in due time if radicals , like lenin , were n't always stirring up trouble . '' `` your honor , lenin had seen his older brother aleksandr executed by the previous tsar for revolutionary activity , and even after the reforms , nicholas continued the same mass repression and executions , as well as the unpopular involvement in world war i , that cost russia so many lives and resources . '' `` hm , this tsar does n't sound like such a capital fellow . '' `` your honor , maybe nicholas ii did doom himself with bad decisions , but lenin deserves no credit for this . when the february 1917 uprisings finally forced the tsar to abdicate , lenin was still exiled in switzerland . '' `` hm , so who came to power ? '' `` the duma formed a provisional government , led by alexander kerensky , an incompetent bourgeois failure . he even launched another failed offensive in the war , where russia had already lost so much , instead of ending it like the people wanted . '' `` it was a constitutional social democratic government , the most progressive of its time . and it could have succeeded eventually if lenin had n't returned in april , sent by the germans to undermine the russian war effort and instigate riots . '' `` such slander ! the july days were a spontaneous and justified reaction against the government 's failures . and kerensky showed his true colors when he blamed lenin and arrested and outlawed his bolshevik party , forcing him to flee into exile again . some democracy ! it 's a good thing the government collapsed under their own incompetence and greed when they tried to stage a military coup then had to ask the bolsheviks for help when it backfired . after that , all lenin had to do was return in october and take charge . the government was peacefully overthrown overnight . '' `` but what the bolsheviks did after gaining power was n't very peaceful . how many people did they execute without trial ? and was it really necessary to murder the tsar 's entire family , even the children ? '' `` russia was being attacked by foreign imperialists , trying to restore the tsar . any royal heir that was rescued would be recognized as ruler by foreign governments . it would 've been the end of everything the people had fought so hard to achieve . besides , lenin may not have given the order . '' `` but it was not only imperialists that the bolsheviks killed . what about the purges and executions of other socialist and anarchist parties , their old allies ? what about the tambov rebellion , where peasants , resisting grain confiscation , were killed with poison gas ? or sending the army to crush the workers in kronstadt , who were demanding democratic self-management ? was this still fighting for the people ? '' `` yes ! the measures were difficult , but it was a difficult time . the new government needed to secure itself while being attacked from all sides , so that the socialist order could be established . '' `` and what good came of this socialist order ? even after the civil war was won , there were famines , repression and millions executed or sent to die in camps , while lenin 's successor stalin established a cult of personality and absolute power . '' `` that was n't the plan . lenin never cared for personal gains , even his enemies admitted that he fully believed in his cause , living modestly and working tirelessly from his student days until his too early death . he saw how power-hungry stalin was and tried to warn the party , but it was too late . '' `` and the decades of totalitarianism that followed after ? '' `` you could call it that , but it was lenin 's efforts that changed russia in a few decades from a backward and undeveloped monarchy full of illiterate peasants to a modern , industrial superpower , with one of the world 's best educated populations , unprecedented opportunities for women , and some of the most important scientific advancements of the century . life may not have been luxurious , but nearly everyone had a roof over their head and food on their plate , which few countries have achieved . '' `` but these advances could still have happened , even without lenin and the repressive regime he established . '' `` yes , and i could 've been a famous rock and roll singer . but how would i have sounded ? '' we can never be sure how things could 've unfolded if different people were in power or different decisions were made , but to avoid the mistakes of the past , we must always be willing to put historical figures on trial .
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`` hm , so who came to power ? '' `` the duma formed a provisional government , led by alexander kerensky , an incompetent bourgeois failure . he even launched another failed offensive in the war , where russia had already lost so much , instead of ending it like the people wanted . ''
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what mistakes did kerensky make that resulted in his overthrow after only a few months ?
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how much can we really know about the universe beyond our galaxy ? the hubble telescope has enabled us to see objects in space as far 13,000,000,000 light years away . but this still does n't give us the answers to all our questions , questions like , `` what is the universe made of ? '' `` which elements are the most abundant ? '' `` does space contain undiscovered forms of matter ? '' `` could there be antimatter stars or galaxies ? '' some of these questions can not be answered solely from visual images , but what if we had messengers bringing us physical data from distant parts of the cosmos , beyond the reach of explorers or satellites ? in a way , we do , and these `` space messengers '' are called cosmic rays . cosmic rays were first discovered in 1912 by victor hess when he set out to explore variations in the atmosphere 's level of radiation , which had been thought to emanate from the earth 's crust . by taking measurements on board a flying balloon during an eclipse , hess demonstrated both that the radiation actually increased at greater altitudes and that the sun could not be its source . the startling conclusion was that it was n't coming from anywhere within the earth 's atmosphere but from outer space . our universe is composed of many astronomical objects . billions of stars of all sizes , black holes , active galactic nuclei , astroids , planets and more . during violent disturbances , such as a large star exploding into a supernova , billions of particles are emitted into space . although they are called rays , cosmic rays consist of these high energy particles rather than the photons that make up light rays . while the light from an explosion travels in a straight line at its famous constant speed , the particles are trapped in extraordinary loops by magnetic shockwaves generated by the explosion . crossing back and forth through these magnetic field lines accelerates them to almost the speed of light before they escape . there are lots of cosmic rays in space , and some of these particles have traveled for billions of years before reaching earth . when they enter our atmosphere , they collide with the molecules there , generating secondary cosmic rays , lighter particles with less energy than the original . most of these are absorbed into the atmosphere , but some are able to reach the ground , even passing through our bodies . at sea level , this radiation is fairly low . but people who spend a lot of time at higher altitudes , such as airline crews , are exposed to much more . what makes cosmic rays useful as messengers is that they carry the traces of their origins . by studying the frequency with which different particles occur , scientists are able to determine the relative abundance of elements , such as hydrogen and helium , within the universe . but cosmic rays may provide even more fascinating information about the fabric of the universe itself . an experiment called the alpha magnetic spectrometer , a.m.s. , has recently been installed on board the international space station , containing several detectors that can separately measure a cosmic ray particle 's velocity , trajectory , radiation , mass and energy , as well as whether the particle is matter or antimatter . while the two are normally indistinguishable , their opposite charges enable them to be detected with the help of a magnet . the alpha magnetic spectrometer is currently measuring 50 million particles per day with information about each particle being sent in real time from the space station to the a.m.s . control room at cern . over the upcoming months and years , it 's expected to yield both amazing and useful information about antimatter , the possible existence of dark matter , and even possible ways to mitigate the effects of cosmic radiation on space travel . as we stay tuned for new discoveries , look to the sky on a clear night , and you may see the international space station , where the alpha magnetic spectrometer receives the tiny messengers that carry cosmic secrets .
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by taking measurements on board a flying balloon during an eclipse , hess demonstrated both that the radiation actually increased at greater altitudes and that the sun could not be its source . the startling conclusion was that it was n't coming from anywhere within the earth 's atmosphere but from outer space . our universe is composed of many astronomical objects .
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why is a.m.s . located in space outside of the atmosphere ?
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i 'm a geographer at middlebury college , and i use digital technologies to reimagine the past . i want to take you to gettysburg , pennsylvania , july 1 , 1863 , we 're right in the middle of the civil war . from the northwest , the confederate forces under robert e. lee , and from the southeast , the union forces under george meade , converge at this place more or less by chance . they did n't plan to fight here . but the battle of gettysburg turns out to be the turning point of the civil war . now , robert e. lee is probably the most famous american general , widely respected . but at gettysburg , he made some crucial mistakes , probably the most important was in ordering pickett 's charge . i 'm going to show you how i took a new look at pickett 's charge with historical maps and gis . my key map was this extraordinary thing , 12 feet by 13 feet , in the vault of treasures at the national archives . here are some of my students at middlebury to give you a sense of that scale . it was recompiled into a finished map the size of a large poster . you can see the layout of the town of gettysburg , you see the undulating shape of the terrain . if you look at other details , you can see forests and orchards and streams and roads . i want you to look at those very fine black lines . those are called contour lines , and they show the elevation at 4-foot intervals , the most detailed elevation i have ever seen . now , before i explain this image , i need to tell you a little about gis . it stands for geographic information systems . it 's a kind of software that allows you to map almost anything . you can also use it to do terrain analysis . for example , if you 're building a ski resort , and you want people to get off the lift and have the most spectacular view possible , you use viewshed analysis that shows you what you can see from a certain point on the terrain . i used that to place myself digitally in the footsteps of robert e. lee , to ask , 'what could he see ? ' and 'what could he not see ? ' that might have influenced his command decisions . now , back to these contour lines . this is the best elevation data that i could find . i traced all of the lines , you see in the black and white drawings , some of those lines , stitched them together , gave them elevation values , and then transformed it , within the gis program , into a continuous terrain . this is a simulation of the ground of the battlefield . now , i 'm ready to place myself in lee 's boots and ask what he could see . the particular moment i want to look at is that battle i mentioned , pickett 's charge . lee makes a crucial decision on the morning of the third day , this is july 3rd , 1863 , the fighting on the previous two days has been fierce . it 's gone back and forth , neither side has a clear advantage . lee goes down to the bottom of the field , we know this , here 's my gorgeous source map again and watch the red circle appear . he goes to the southern end of the battlefield at about 8:00 in the morning with his binoculars and looks through them to figure out where to attack the union line , where are they most vulnerable . now , in this next image , i 'm going to show you the gis process called viewshed analysis , along with lee 's line of sight in that sort of reddish cone is the direction we think he was looking . viewshed analysis , remember , tells me what i can see and what i ca n't see from a certain point , so in this map , the grey area is what lee could n't see . the clear area , where you see that historic map coming through , is what he could 've definitely seen . notice how much of the right side of the map is in grey . now , we add another crucial piece of information . someone named john bachelder , a landscape painter from new hampshire , went down to the battlefield as soon as he heard about the fight , in order to document where troops had been and to try to paint the battle . he ended up getting $ 10,000 from congress in order to document troop positions down to the half hour . he produced 24 maps that we also digitized and brought into the gis . and this next map shows that troop position information ; it 's crucial for understanding what lee could and what he could n't see . now , if you look closely at this map , you might be able to see kind of the middle is a black oval around an area that 's relatively clear . the blue markings in that black oval are union troops that i 'm definitely sure that lee could see . but if you look to the right of that , you 'll see an awful lot of blue markings . those are union troops in the shadows . now , we know that on the night before lee 's reconnaissance so , the night of july 2nd , he sent out scouts . of course , he wanted to know where the federal troops were . but quite astonishingly , we have no explanation for this . the scouts came back saying , 'do n't worry , general lee . we did n't see any troops to the east , ' in your map to the right , 'of the roundtops , some really big hills . ' we do n't know if they got drunk or fell asleep , but they did n't see almost a third of the union army . so lee is blind from his scouts , and from his viewpoint , he 's also blind . he decides to attack what he thinks is the weak middle of the union line , not knowing about where the rest of the troops are . so if you look in the middle of this image , there 's a gap in the union line from where the blue soldiers are at the north of the battlefield and at the south . so let me now play out , using these troop positions , pickett 's charge . the confederate soldiers are lined up on the west side of the battlefield , standing under the trees . 18,000 men who first begin to walk and then trot and then run across open farm fields with their rifles leveled at the federal line . now , the union army has about 15-20 minutes to organize itself . they see that the confederates are converging on the middle of their line , and what do they do ? the blue arrow here , representing movement of the union troops , they pull their troops toward that weak center , and let me show you how they were able to concentrate those men in a remarkably short period of time . lee did n't know that the union could 've done this . you see now , they 're standing like a wall , ready to receive the confederate assault , which happens between 1:30 and about 2:00 , 2:30 in the afternoon . there is tremendously fierce fighting , hand-to-hand combat . now these blue lines , coming in between 2-2:30 in the afternoon , are pulling more reserves , more reinforcements , to that weak center of the union line . what happens ? the union soliders drive the confederates off . lee rides out , among his men , at 3:00 in the afternoon , saying , 'i 'm sorry . it 's my fault . it 's my fault . ' this story of sight has been a missing part of the battle of gettysburg . here 's their retreat . historians have not been previously able to figure out what he could and could n't see . i think it helps explain his decision . why ? because from his point of view , the federals were very weak . he was attacking at the logical place , but without full knowledge , he set his men out for a dreadful defeat . now , there 's one more piece to this story . last summer was the 150th anniversary of the battle of gettysburg . and i was able to work with a 3d animator , so we were able to use the gis information to render the terrain issue as you see it here . and my closing story is about how sight helped the other side . a federal general named gk warren stood in the spot that this panoramic view is showing you , looking out over the battlefield . and at a key moment on day two , he was able to see on the far horizon confederate soldiers emerging out of the trees who were about to attack little roundtop . he called in reinforcements just in time and saved the day for the union , setting the stage for the union almost-victory on day three . so , i hope that all of you who are so gifted with digital technologies will begin to think about how you can use them for history . it can be amazing . thank you .
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he called in reinforcements just in time and saved the day for the union , setting the stage for the union almost-victory on day three . so , i hope that all of you who are so gifted with digital technologies will begin to think about how you can use them for history . it can be amazing .
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how can we use digital technologies in new ways as we learn history ? what about other disciplines ?
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what is proof ? and why is it so important in mathematics ? proofs provide a solid foundation for mathematicians logicians , statisticians , economists , architects , engineers , and many others to build and test their theories on . and they 're just plain awesome ! let me start at the beginning . i 'll introduce you to a fellow named euclid . as in , `` here 's looking at you , clid . '' he lived in greece about 2,300 years ago , and he 's considered by many to be the father of geometry . so if you 've been wondering where to send your geometry fan mail , euclid of alexandria is the guy to thank for proofs . euclid is not really known for inventing or discovering a lot of mathematics but he revolutionized the way in which it is written , presented , and thought about . euclid set out to formalize mathematics by establishing the rules of the game . these rules of the game are called axioms . once you have the rules , euclid says you have to use them to prove what you think is true . if you ca n't , then your theorem or idea might be false . and if your theorem is false , then any theorems that come after it and use it might be false too . like how one misplaced beam can bring down the whole house . so that 's all that proofs are : using well-established rules to prove beyond a doubt that some theorem is true . then you use those theorems like blocks to build mathematics . let 's check out an example . say i want to prove that these two triangles are the same size and shape . in other words , they are congruent . well , one way to do that is to write a proof that shows that all three sides of one triangle are congruent to all three sides of the other triangle . so how do we prove it ? first , i 'll write down what we know . we know that point m is the midpoint of ab . we also know that sides ac and bc are already congruent . now let 's see . what does the midpoint tell us ? luckily , i know the definition of midpoint . it is basically the point in the middle . what this means is that am and bm are the same length , since m is the exact middle of ab . in other words , the bottom side of each of our triangles are congruent . i 'll put that as step two . great ! so far i have two pairs of sides that are congruent . the last one is easy . the third side of the left triangle is cm , and the third side of the right triangle is - well , also cm . they share the same side . of course it 's congruent to itself ! this is called the reflexive property . everything is congruent to itself . i 'll put this as step three . ta dah ! you 've just proven that all three sides of the left triangle are congruent to all three sides of the right triangle . plus , the two triangles are congruent because of the side-side-side congruence theorem for triangles . when finished with a proof , i like to do what euclid did . he marked the end of a proof with the letters qed . it 's latin for `` quod erat demonstrandum , '' which translates literally to `` what was to be proven . '' but i just think of it as `` look what i just did ! '' i can hear what you 're thinking : why should i study proofs ? one reason is that they could allow you to win any argument . abraham lincoln , one of our nation 's greatest leaders of all time used to keep a copy of euclid 's elements on his bedside table to keep his mind in shape . another reason is you can make a million dollars . you heard me . one million dollars . that 's the price that the clay mathematics institute in massachusetts is willing to pay anyone who proves one of the many unproven theories that it calls `` the millenium problems . '' a couple of these have been solved in the 90s and 2000s . but beyond money and arguments , proofs are everywhere . they underly architecture , art , computer programming , and internet security . if no one understood or could generate a proof , we could not advance these essential parts of our world . finally , we all know that the proof is in the pudding . and pudding is delicious . qed .
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euclid set out to formalize mathematics by establishing the rules of the game . these rules of the game are called axioms . once you have the rules , euclid says you have to use them to prove what you think is true .
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kennedy refers to “ the rules of the game. ” these are
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how is it that so many intergalactic species in movies and tv just happen to speak perfect english ? the short answer is that no one wants to watch a starship crew spend years compiling an alien dictionary . but to keep things consistent , the creators of star trek and other science-fiction worlds have introduced the concept of a universal translator , a portable device that can instantly translate between any languages . so is a universal translator possible in real life ? we already have many programs that claim to do just that , taking a word , sentence , or entire book in one language and translating it into almost any other , whether it 's modern english or ancient sanskrit . and if translation were just a matter of looking up words in a dictionary , these programs would run circles around humans . the reality , however , is a bit more complicated . a rule-based translation program uses a lexical database , which includes all the words you 'd find in a dictionary and all grammatical forms they can take , and set of rules to recognize the basic linguistic elements in the input language . for a seemingly simple sentence like , `` the children eat the muffins , '' the program first parses its syntax , or grammatical structure , by identifying the children as the subject , and the rest of the sentence as the predicate consisting of a verb `` eat , '' and a direct object `` the muffins . '' it then needs to recognize english morphology , or how the language can be broken down into its smallest meaningful units , such as the word muffin and the suffix `` s , '' used to indicate plural . finally , it needs to understand the semantics , what the different parts of the sentence actually mean . to translate this sentence properly , the program would refer to a different set of vocabulary and rules for each element of the target language . but this is where it gets tricky . the syntax of some languages allows words to be arranged in any order , while in others , doing so could make the muffin eat the child . morphology can also pose a problem . slovene distinguishes between two children and three or more using a dual suffix absent in many other languages , while russian 's lack of definite articles might leave you wondering whether the children are eating some particular muffins , or just eat muffins in general . finally , even when the semantics are technically correct , the program might miss their finer points , such as whether the children `` mangiano '' the muffins , or `` divorano '' them . another method is statistical machine translation , which analyzes a database of books , articles , and documents that have already been translated by humans . by finding matches between source and translated text that are unlikely to occur by chance , the program can identify corresponding phrases and patterns , and use them for future translations . however , the quality of this type of translation depends on the size of the initial database and the availability of samples for certain languages or styles of writing . the difficulty that computers have with the exceptions , irregularities and shades of meaning that seem to come instinctively to humans has led some researchers to believe that our understanding of language is a unique product of our biological brain structure . in fact , one of the most famous fictional universal translators , the babel fish from `` the hitchhiker 's guide to the galaxy '' , is not a machine at all but a small creature that translates the brain waves and nerve signals of sentient species through a form of telepathy . for now , learning a language the old fashioned way will still give you better results than any currently available computer program . but this is no easy task , and the sheer number of languages in the world , as well as the increasing interaction between the people who speak them , will only continue to spur greater advances in automatic translation . perhaps by the time we encounter intergalactic life forms , we 'll be able to communicate with them through a tiny gizmo , or we might have to start compiling that dictionary , after all .
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morphology can also pose a problem . slovene distinguishes between two children and three or more using a dual suffix absent in many other languages , while russian 's lack of definite articles might leave you wondering whether the children are eating some particular muffins , or just eat muffins in general . finally , even when the semantics are technically correct , the program might miss their finer points , such as whether the children `` mangiano '' the muffins , or `` divorano '' them .
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using which part of theoretical linguistics , how would a machine translator distinguish `` child '' from `` children '' ?
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what causes , say , heroin addiction ? this is a really stupid question , right ? it ’ s obvious ; we all know it ; heroin causes heroin addiction . here ’ s how it works : if you use heroin for 20 days , by day 21 , your body would physically crave the drug ferociously because there are chemical hooks in the drug . that ’ s what addiction means . but there ’ s a catch . almost everything we think we know about addiction is wrong . if you , for example , break your hip , you ’ ll be taken to a hospital and you ’ ll be given loads of diamorphine for weeks or even months . diamorphine is heroin . it ’ s , in fact , much stronger heroin than any addict can get on the street because it ’ s not contaminated by all the stuff drug dealers dilute it with . there are people near you being given loads of deluxe heroin in hospitals right now . so at least some of them should become addicts ? but this has been closely studied ; it doesn ’ t happen . your grandmother wasn ’ t turned into a junkie by her hip replacement . why is that ? our current theory of addiction comes in part from a series of experiments that were carried out earlier in the 20th century . the experiment is simple : you take a rat and put it in a cage with two water bottles . one is just water , the other is water laced with heroin or cocaine . almost every time you run this experiment , the rat will become obsessed with the drugged water and keep coming back for more and more , until it kills itself . but in the 1970s , bruce alexander , a professor of psychology , noticed something odd about this experiment : the rat is put in the cage all alone . it has nothing to do but take the drugs . what would happen , he wondered , if we tried this differently ? so he built rat park , which is basically heaven for rats ; it ’ s a lush cage where the rats would have colored balls , tunnels to scamper down , plenty of friends to play with , and they could have loads of sex— everything a rat about town could want . and they would have the drugged water and the normal water bottles . but here ’ s the fascinating thing : in rat park , rats hardly ever use the drugged water ; none of them ever use it compulsively ; none of them ever overdose . but maybe this is a quirk of rats , right ? well , helpfully , there was a human experiment along the same lines : the vietnam war . 20 % of american troops in vietnam were using a lot of heroin . people back home were really panicked , because they thought there would be hundreds of thousands of junkies on the streets of the united states when the war was over . but a study followed the soliders home and found something striking : they didn ’ t go to rehab ; they didn ’ t even go into withdrawal ; 95 % of them just stopped after they got home . if you believe the old theory of addiction , that makes no sense . but if you believe prof. alexander ’ s theory , it makes perfect sense , because if you ’ re put into a horrific jungle in a foreign country where you don ’ t want to be , and you could be forced to kill or die at any moment , doing heroin is a great way to spend your time ; but if you go back to your nice home with your friends and your family , it ’ s the equivalent of being taken out of that first cage and put into a human rat park ; it ’ s not the chemicals , it ’ s your cage . we need to think about addiction differently . human beings have an innate need to bond and connect . when we are happy and healthy , we will bond with the people around us . but when we can ’ t , because we ’ re traumatized , isolated , or beaten down by life , we will bond with something that gives us some sense of relief . it might be endlessly checking a smartphone ; it might be pornography , video games , reddit , gambling , or it might be cocaine . but we will bond with something , because that is our human nature . the path out of unhealthy bonds is to form healthy bonds , to be connected to people you want to be present with . addiction is just one symptom of the crisis of disconnection that ’ s happening all around us . we all feel it . since the 1950s , the average number of close friends an american has has been steadily declining . at the same time , the amount of floor space in their homes has been steadily increasing . to choose floor space over friends , to choose stuff over connection . the war on drugs we ’ ve been fighting for almost a century now has made everything worse . instead of helping people heal and getting their life together , we have cast them out from society , we have made it harder for them to get jobs and become stable , we take benefits and support away from them if we catch them with drugs , we throw them in prison cells , which are literally cages , we put people who are not well in a situation which makes them feel worse and hate them for not recovering . for too long , we ’ ve talked only about individual recovery from addiction . but we need now to talk about social recovery . because something has gone wrong with us as a group . we have to build a society that looks a lot more like rat park and a lot less like those isolated cages . we are going to have to change the unnatural way we live and rediscover each other . the opposite of addiction is not sobriety ; the opposite of addiction is connection . this video is a collaboration with johann hari , the author of the book “ chasing the scream : the first and last days of the war on drugs ” . he was very kind to work with us on this video to spread the word . we recommend that you give the book a try . our videos are made thanks to your support on patreon.com . if you want to help us make more of them , we really appreciate your support . we made an interactive version of this video together with some friends . see the link in the description . subtitles by the amara.org community
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if you , for example , break your hip , you ’ ll be taken to a hospital and you ’ ll be given loads of diamorphine for weeks or even months . diamorphine is heroin . it ’ s , in fact , much stronger heroin than any addict can get on the street because it ’ s not contaminated by all the stuff drug dealers dilute it with .
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according to this video why is diamorphine more potent than heroin that is sold by drug dealers ?
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it 's estimated that for every 10,000 bills in the u.s. , one of those bills is fake . that may not sound like much , but it adds up to millions of dollars in cold hard cash . counterfeit money has the potential to cause all sorts of problems , from leaving you short $ 20 to destabilizing national economies . but do n't worry . you can help catch the counterfeits . all you need are some simple tools and a bit of chemistry . first up , the anti-counterfeit detection pen . the pen looks like a highlighter and contains a solution of potassium iodide and elemental iodine . it reveals of the presence of starch , which is commonly used to strengthen regular printer paper , but wo n't be found in real money . that 's because authentic bills are made of cotton and linen and are threaded with tiny red and blue fibers . that material is made by a single , highly-guarded company called crane and company , which has been printing currency since paul revere asked them to help finance the revolutionary war . the starch in many counterfeit bills , on the other hand , is made of two molecules : amylopectin and amylose . it 's amylose that gives the fake away . its long chain of sugar molecules connected by oxygen atoms forms a helical structure , like dna . iodide likes to squeeze inside this coil , forming a new compound that leaves a dark mark on the paper . however , in the absence of starch , there is no chemical reaction and the mark will look light yellow . so if the fake is n't printed on starchy paper , iodine solutions ca n't help you . that 's one of the reasons u.s. bills printed since 1996 have been chemically enhanced to include another counterfeit countermeasure : a strip that fluoresces under uv light . that 's the same kind of light used at black light parties and airport security lines . the polyester strip printed with invisble ink is just one millimeter wide and is found in different positions depending on a bill 's value . if you hold your dollar up to natural light , you can see the amount and the word usa printed on the band . but under uv light , these strips really shine . they contain molecules that can be excited by absorbing certain amounts of energy , specifically , that given off by common uv light sources . as these excited molecules return to their original states , they lose a bit of energy as heat and then radiate the rest as light . energy is inversely related to wavelength , which means that the longer wavelengths have lower energy . so the lower energy light given off by the strip means longer wavelengths that fall in the visible range , and suddenly we can see that which had been invisible . and if a glowing strip does n't show up on a recent bill , you have a fake on your hands . for times when you 're not dealing with counterfeit masterminds , looking for simple visual cues will do . make sure the portrait looks lifelike and not flat , the seal has perfectly even sawtooth points , the inked border is unbroken , and the serial number has precisely equal spacing between each number . so the next time you come across some dubious dough , have a closer look , pull out your iodine solution , or take it to a rave and you just might catch a counterfeit .
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all you need are some simple tools and a bit of chemistry . first up , the anti-counterfeit detection pen . the pen looks like a highlighter and contains a solution of potassium iodide and elemental iodine .
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counterfeit detection pens contain solutions of potassium iodide and _____ ?
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good morning , john ! today is the day after thanksgiving here in america . traditionally , the day when we buy all the things ! actually , more traditionally at my house , it 's the day when we do n't leave the house ; because black friday.. terrifies me . for people who are n't american , the very ominous-sounding black friday is an accident of history . so , back in 1621 , it was hard livin ' here in america ; and the first english settlers had a really bountiful crop . apparently . this is somewhat mythological ... and , it was on a thursday ; and they were thankful ! that inspired a holiday ; which is a nice kind of idea for a holiday , where you just talk about the things that you 're thankful for . and eat a bunch of food ! you also eat a bunch of food . until the 1860 's , different states celebrated this holiday on different days . until abraham lincoln said : `` this.. is the day ! we 're gon na have a national day . `` ; and , the south was like : `` we 're not even part of you anymore . what are you talking about ? ! '' but then , when we got back together again , that was good ; and it became the national holiday . the fourth thursday in november . now , because it 's a national holiday on the thursday , you also sort of get that friday as a de facto day off . 'cause you do n't want to go back to work for one day and then have the weekend ; that 's just dumb ! in the '60 's [ 1960 's ] , because so many people were going on vacation on this day , or , to a lesser extent , going shopping ; this became such a terrible traffic mess that police and taxi drivers started calling it `` black friday '' . as stores , and also just general consumerist cultures , started pushing the idea of christmas shopping further and further away from christmas ; the big block in the road , where you ca n't push it back any further , is thanksgiving . 'cause that 's its own holiday . you ca n't start christmas before thanksgiving . and so , black friday became the official tipping point into the consumerist bonanza that is the holiday shopping season ! despite the fact that it has kind of this ominous-sounding name , it has been billed as the biggest and most important and best holiday shopping day of the year ; which is actually not true . we are.. a nation of procrastinators ; and thus , the biggest shopping day of the year is christmas eve . it seems a little bit upsetting that the day after we all get done telling the world why we should be satisfied with our lives , we are.. barraged with an advertising blitz showing us all of the things that we lack ! at the same time , it is very important to the american economy . i mean , you ca n't really get angry at people for wanting to give each other things ... and yes , dftba.com has its own black friday and cyber monday deals ; and you can go to dftba.com and check those out now . it 's also our 4th anniversary of being a company , which is very exciting ! and , to celebrate that fourth anniversary , all shipping within the united states this weekend , starting tomorrow , i think , is just $ 4.00 ! no matter what you buy ! ! but , i do think it 's important that we do n't just scrub the idea of satisfaction and thankfulness out of our brains as soon as we 're done for thanksgiving . and so , on this black friday , i want to continue being thankful . i 'm thankful to my wonderful and supportive parents ; to my beautiful , and intelligent , and hilarious wife . i 'm thankful to my new wii u . if you want to go to youtube.com/hankgames , you can see us playing the new super mario brothers there soon . i 'm thankful to all of my great friends here in missoula and across the world . i 'm thankful to finally have a robust and stable forum that can handle the weight of nerdfighteria . there 's a link in the description . i 'm thankful to youtube and google for funding scishow and crash course , and for supporting vlogbrothers , and all of our endeavors through the years . i 'm thankful to reddit , and qi , and mental floss magazine , for making sure that i keep learning interesting things . i 'm thankful to jonas salk for giving away the patent to his polio vaccine to the world , so that it could be less expensive to manufacture ; and tim berners-lee for doing basically the same thing with the internet . i 'm thankful to the nerdcrafteria minecraft server and tumblr , and the ning ; and all the other places on the internet where nerdfighters do nerdfighter things . and , i 'm thankful to all the wonderful , thoughtful , intelligent people who watch and support the things that i do on the internet ; even when it 's sappy , silly videos like this one . and i 'm thankful , of course , for my brother who 's always driving me to do new and interesting and difficult things ; and who 's raising a wonderful family , and who says wise and intelligent things on tumblr . and john , i 'll see you on tuesday . *music plays*
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the fourth thursday in november . now , because it 's a national holiday on the thursday , you also sort of get that friday as a de facto day off . 'cause you do n't want to go back to work for one day and then have the weekend ; that 's just dumb !
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how did black friday become an unofficial national holiday in the united states ?
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what do charles darwin , michael jordan , and yoda have in common ? they , like many other historical and fictive individuals , are bald , in some cases by their own choice . for centuries , a shining dome has been a symbol of intelligence , but despite this , many balding people still wish their hair would return . scientists have long pondered , `` why do some people lose their hair , and how can we bring it back ? '' the full-headed among us have about 100,000 to 150,000 hairs on our scalps , and scientists have discovered two things about this dense thicket . firstly , the sprouting hair we see is mostly made up of keratin , the protein leftover from dead cells that are forced upwards as new cells grow beneath them . secondly , the structures that drive hair growth are called hair follicles , a network of complex organs that forms before we 're born , and grows hair in an everlasting cycle . this cycle has three main phases . the first is anagen , the growth phase , which up to 90 % of your hair follicles are experiencing right now , causing them to push up hair at a rate of one centimeter per month . anagen can last for two to seven years , depending on your genes . after this productive period , signals within the skin instruct some follicles to enter a new phase known as catagen , or the regressing stage , causing hair follicles to shrink to a fraction of their original length . catagen lasts for about two to three weeks and cuts blood supply to the follicle , creating a club hair , meaning it 's ready to be shed . finally , hairs enter telogen , the resting phase , which lasts for ten to twelve weeks , and affects about 5-15 % of your scalp follicles . during telogen , up to 200 club hairs can be shed in a day , which is quite normal . then , the growth cycle begins anew . but not all heads are hairy , and , in fact , some of them grow increasingly patchy over time in response to bodily changes . 95 % of baldness in men can be attributed to male pattern baldness . baldness is inherited , and in people with this condition , follicles become incredibly sensitive to the effects of dihydrotestosterone , a hormonal product made from testosterone . dht causes shrinkage in these overly sensitive follicles , making hair shorter and wispier . but loss is n't sudden . it happens gradually , along a metric known as the norwood scale , which describes the severity of hair loss . first , hair recedes along the temples , then hair on the crown begins to thin in a circular pattern . at the highest rating on the scale , these balding areas meet and expand dramatically , eventually leaving only a ring of sparse hair around the temples and the back of the head . genetics is n't all that drives hair loss . long periods of stress can release signals that shock follicles and force them into the resting phase prematurely . some women experience this after childbirth . follicles might also lose the ability to go into anagen , the growth phase . people going through chemotherapy treatment temporarily experience this . but while balding may look permanent , scientific investigation has revealed the opposite . below the skin 's surface , the roots that give rise to our hair actually remain alive . using this knowledge , scientists have developed drugs that shorten the resting phase , and force follicles into anagen . other drugs combat male pattern baldness by blocking the conversion of testosterone to dht so that it does n't affect those sensitive follicles . stem cells also play a role in regulating the growth cycle , and so scientists are investigating whether they can manipulate the activity of these cells to encourage follicles to start producing hair again . and in the meantime , while scientists hone their hair-reviving methods , anyone going bald , or considering baldness , can remember that they 're in great company .
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at the highest rating on the scale , these balding areas meet and expand dramatically , eventually leaving only a ring of sparse hair around the temples and the back of the head . genetics is n't all that drives hair loss . long periods of stress can release signals that shock follicles and force them into the resting phase prematurely .
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hair loss such as those induced by chemotherapy and childbirth can result in psychological stress . what forms of social support can be appropriate to address this ?
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françois-marie arouet was born in paris in 1694 his father , a well-established lawyer , sent him to the best school in the capital , and by all accounts , he was a brilliant student . the young arouet , decided at an early age to make his name as a writer , or rather to remake his name , as the first thing he did was to change his name to voltaire . the 18th century is often referred to as the age of reason , or the age of enlightenment , but sometimes more fairly simply as the age of voltaire . so , changing his name was a good call . the age of arouet , which is not of work quite as well . voltaire was precociously talented as a poet . at the age of only 24 , he had his first verse tragedy performed at the comédie-française . by then , he 'd already begun work on an epic poem about the french religious civil wars of the 16th century , about the french religious civil wars of the 16th century , by pragmatically converting from protestantism to catholicism . this was to be a subject dear to voltaire 's heart , for under the guise of writing a national epic , he was dwelling at length on the bloody consequences of religious intolerance . right from the start , voltaire 's views on religion were expressed robustly . he was not an atheist . in part , because he thought that some minimal belief in a deity was useful for social cohesion . voltaire 's god had created the world , instilled in us a sense of good and evil and then basically taken a back seat . this was known as rational religion , or in the 18th century called natural religion , or deism . and it had no truck with metaphysics of any kind . voltaire was basically a man of reason , who loathed fanaticism , idolatry and superstition . that men can kill each other to defend some bit of religious doctrine , which they scarcely understand , is something he found repellent . and he reserved his greatest hatred for the clerics , who exploited the credulity of believers to maintain their own power base . voltaire wanted religion but not the church . for obvious reasons , the catholic authorities were not keen for voltaire 's poem about henry iv , la henriade , to be published in france . so voltaire decided to go and publish it in london instead , and in 1726 , went and traveled to england . what began as a business trip soon turned , however , into something quite different . and voltaire ended up staying in england for some two and a half years . he learned to speak english fluently , got to know writers and politicians , and became a great admirer of english protestant culture . he decided to write a book about his experience of england . and the letters concerning the english nation appeared first in english in 1733 . the french authorities were horrified . the book was censored and voltaire only narrowly avoided prison . that 's because the book presented an informal portrait of english culture , in a witty and ironical style looking in turn at religion , politics , science and literature , in ways that were critical implicitly of french culture and politics . here , for example , is how voltaire presents the royal exchange , a handsome building in the heart of the city of london , where merchants from across the world would meet to transact business . `` take a view of the royal exchange , '' voltaire wrote , where the representatives of all nations meet for the benefit of mankind . there the jew , the muhammadan and a christian transact together as though they all profess the same religion , and give the name of infidel to none but the bankrupts . there the presbyterian confides in the anabaptist , and the churchman depends on the quaker ’ s word . at the breaking up of this pacific and free assembly , some will withdraw to the synagogue , and others to take a glass . this man goes and is baptised in a great tub , in the name of the father , son and holy ghost : that man has his son ’ s foreskin cut off , whilst a set of hebrew words ( quite unintelligible to him ) are mumbled over his child . if one religion only were allowed in england , the government would very possibly become arbitrary ; if there were but two , the people would cut one another ’ s throats ; but as there as such a multitude , they all live happy and in peace . '' voltaire 's message is clear . religious differences are trivial and separate men , while trade is important and brings them together . his conclusion , that the plurality of religions in england leads to a more peaceful society , is , of course , a covert criticism of france , where the catholic church was so dominant . the letters concerning the english nation , also discuss locke and newton , thinkers then poorly known in france the subject-matter might seem challenging , but voltaire is a past master popularising difficult material . ask any schoolchild today what they know about newton , and they 'll tell you about the apple falling on his head , and the survival of this anecdote is due entirely to voltaire . he heard it from newton 's niece and immediately understood that this simple homely image was the perfect way of conveying the simplicity of newton 's explanation of the force of gravity . after voltaire used the story in his letters concerning the english nation , everyone remembered it and voltaire left his mark on english popular culture . voltaire struggled with the question of good and evil the problem at the heart of his best-known work , candide which was published in 1759 and was a best seller from the moment it appeared . translated into every possible language , it remains the most widely read work of the european enlightenment . it 's even left its mark on our language expressions like 'pour encourager les autres ' to encourage the others or 'il faut cultiver le jardin ' , we must cultivate our garden have entered common usage . 'in the best of all possible worlds ' , yes , that 's another one speakers of french or english quote candide , without even realising it . and that 's the sure mark of a classic . candide is a timeless work , as satire of the human condition , but it 's also work of the enlightenment and its philosophical theme is announced in the title : `` candide '' or `` optimism '' . the hero of candide , as his name tells us , is an innocent anti-hero . he is in thrall to his tutor , pangloss , who preaches the philosophy of optimism . this is not 'optimism ' in the modern sense of looking on the bright side . optimism , spelled with a capital o and as expounded by the german philosopher , leibniz , was an attempt to answer the age-old problem of evil . why , if god is good , does he permit the existence of evil in the world ? to which the 18th century leibnizian optimist replies , evil is all part of some greater pattern of good : 'all partial evil , universal good ' as the english poet `` pope '' put it . in other words , evil does n't really exist at all . it 's just something which man imagines because of his limited view of the world . you might think this sounds like a bit of a confidence trick , voltaire certainly did , but this idea did find widespread acceptance in the 18th century . candide 's great mission was to put this philosophy to the test . ejected from his comfortable home in an obscure german castle , after trying to seduce the baron 's beautiful daughter , cunégonde , voltaire 's hero , candide , undergoes many trials and tribulations : conscripted into the army , he fights in a war , then deserts , only to find himself a witness to an earthquake in lisbon . candide is repeatedly brought face to face with evil in its most extreme forms : moral evil , in the case of the earthquake , where man is not apparently to blame ; and most of all human evil , such as the war , where man is very definitely to blame . pangloss 's breezy optimism is clearly an inadequate response to enormities of evil on this scale . eventually , even candide comes to realize this : to quote from the book , 'and sometimes pangloss would say to candide : after 1760 , voltaire took up residence in the château at ferney , just outside geneva . by now , he was the most famous living writer in europe , and he became widely known as the ‘ patriarch of ferney ’ . he took up a number of public causes . in 1761 , a protestant merchant jean calas , was accused of murdering his son and sentenced by the judges of toulouse to be tortured and then broken on the wheel . the legal processes were , to say the least , irregular , and the suspicions grew that the judges in his catholic city had acted with excessive zeal out of religious bigotry . voltaire became involved in the case and mounted an energetic campaign to rehabilitate calas ’ memory and help the members of his family , who had been left destitute . he wrote letters to those in authority and published a stream of pamphlets , culminating in 1763 in his traité sur la tolérance , which begins with the historical facts of the calas case and broadens out into a history of religious intolerance in european culture . voltaire 's writings had enormous impact on public opinion , and eventually the judges in paris quashed the judgment of the toulouse court . too late to save calas , but a huge victory for voltaire , who had learnt an important lesson about how change could be brought about through the pressure of public opinion . voltaire said of himself that he ‘ wrote to act ’ , and he wanted his writings to change the way people thought and behaved . in leading his crusades against fanaticism , he even invented a campaign slogan , ecrasez l ’ infâme ! , which translates roughly as ‘ crush the despicable ! ’ . l ’ infâme stands here for everything that voltaire hates , everything that he had spent his life fighting : superstition , intolerance , irrational behaviour of every kind . we should never forget that voltaire was also a brilliant writer , one of the greatest stylist the french language has ever known . the power of his ideas had a lot to do with the power of his expression . many writers made fun of miracles . no one did so hilariously as voltaire . always , voltaire had an ear for the telling phrase : it 's a good line , even in english , and better still in the original french where it is more memorable because it is a classical alexandrine line in 12 syllables : si dieu n ’ existait pas , il faudrait l ’ inventer . voltaire 's legacy in our present debates about religious toleration remain extremely potent . hardly a week passes without an article in the press quoting : ‘ i disapprove of what you say , but i will defend to the death your right to say it. ’ this rallying cry of tolerant multiculturalism is so potent that if voltaire had n't said it , we would have had to invent it , which is what happened . the expression was invented by an english woman in 1906 . no matter , it expresses a truth which is fundamentally important to our culture , so we have adopted the phrase and decided that voltaire said it . voltaire , his name has become synonymous with a set of liberal values : freedom of speech , rejection of bigotry and superstition , belief in reason and tolerance . it 's a unique , and nowadays , extremely precious legacy .
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pangloss 's breezy optimism is clearly an inadequate response to enormities of evil on this scale . eventually , even candide comes to realize this : to quote from the book , 'and sometimes pangloss would say to candide : after 1760 , voltaire took up residence in the château at ferney , just outside geneva . by now , he was the most famous living writer in europe , and he became widely known as the ‘ patriarch of ferney ’ .
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which of these popular phrases came from candide ?
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in 1845 , ireland 's vast potato fields were struck by an invasive fungal disease that rapidly infested this staple crop . the effect was devastating . one million people died of famine , and over a million more were forced to leave ireland . nowadays , we avoid such agricultural catastrophes with the help of pesticides . those are a range of manmade chemicals that control insects , unwanted weeds , funguses , rodents , and bacteria that may threaten our food supply . they 've become an essential part of our food system . as populations have grown , monoculture , single crop farming , has helped us feed people efficiently . but it 's also left our food vulnerable to extensive attack by pests . in turn , we 've become more dependent on pesticides . today , we annually shower over 5 billion pounds of pesticides across the earth to control these unwanted visitors . the battle against pests , especially insects , has marked agriculture 's long history . records from thousands of years ago suggest that humans actively burned some of their crops after harvest to rid them of pests . there 's even evidence from ancient times that we recruited other insects to help . in 300 a.d. , chinese farmers specially bred ferocious predatory ants in orange orchards to protect the trees from other bugs . later , as large-scale farming spread , we began sprinkling arsenic , lead , and copper treatments on crops . but these were incredibly toxic to humans as well . as our demand for more , safer produce increased , so did the need for effective chemicals that could control pests on a grander scale . this ushered in the era of chemical pesticides . in 1948 , a swiss chemist named paul hermann müller was awarded a nobel prize for his discovery of dichlorodiphenyltrichloroethane , also known as ddt . this new molecule had unparalleled power to control many insect species until the 1950s , when insects became resistant to it . worse , the chemical actually drove dramatic declines in bird populations , poisoned water sources , and was eventually found to cause long-term health problems in humans . by 1972 , ddt had been banned in the united states , and yet traces still linger in the environment today . since then , chemists have been searching for alternatives . with each new wave of inventions , they 've encountered the same obstacle - rapid species evolution . as pesticides destroy pest populations , they leave behind only the most resistant individuals . they then pass on their pesticide-resisting genes to the next generation . that 's lead to the rise of super bugs , such as the colorado potato beetle , which is resistant to over 50 different insecticides . another downside is that other bugs get caught in the crossfire . some of these are helpful predators of plant pests or vital pollinators , so erasing them from agriculture wipes out their benefits , too . pesticides have improved over time and are currently regulated by strict safety standards , but they still have the potential to pollute soil and water , impact wildlife , and even harm us . so considering all these risks , why do we continue using pesticides ? although they 're imperfect , they currently may be our best bet against major agricultural disasters , not to mention mosquito-born diseases . today , scientists are on a quest for alternative pest control strategies that balance the demands of food production with environmental concerns . nature has become a major source of inspiration , from natural plant and fungal chemicals that can repel or attract insects , to recruiting other insects as crop bodyguards . we 're also turning to high-tech solutions , like drones . programmed to fly over crops , these machines can use their sensors and gps to carry out more targeted sprays that limit a pesticide 's wider environmental impact . with a combination of biological understanding , environmental awareness , and improved technologies , we have a better chance of finding a holistic solution to pests . chemical pesticides may never shake their controversial reputation , but with their help , we can ensure that agricultural catastrophes stay firmly in our past .
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but these were incredibly toxic to humans as well . as our demand for more , safer produce increased , so did the need for effective chemicals that could control pests on a grander scale . this ushered in the era of chemical pesticides .
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today , ladybugs are used to control aphids ( a pest that suck sap from plants ) , just like predatory ants were used to control pests in chinese orchards . what could be the advantages and disadvantages of using insects to combat pests ?
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conventional wisdom about diets , including government health recommendations , seems to change all the time . and yet , ads routinely come about claiming to have the answer about what we should eat . so how do we distinguish what 's actually healthy from what advertisers just want us to believe is good for us ? marketing takes advantage of the desire to drop weight fast , and be stronger , slimmer , and brighter . and in the big picture , diet plans promising dramatic results , known as fad diets , are just what they seem : too good to be true . so where do diet fads even come from ? while the ancient greeks and romans rallied behind large-scale health regimens centuries earlier , this phenomenon began in earnest in the victorian era with crazes like the vinegar diet and the banting diet . since then , diets have advised us all sorts of things : to excessively chew , to not chew at all , to swallow a grapefruit per meal , non-stop cabbage soup , even consumption of arsenic , or tapeworms . if the idea of diet crazes has withstood history , could this mean that they work ? in the short term , the answer is often yes . low-carbohydrate plans , like the popular atkins or south beach diets , have an initial diuretic effect . sodium is lost until the body can balance itself out , and temporary fluid weight loss may occur . with other high-protein diets , you might lose weight at first since by restricting your food choices , you are dropping your overall calorie intake . but your body then lowers its metabolic rate to adjust to the shift , lessening the diet 's effect over time and resulting in a quick reversal if the diet is abandoned . so while these diets may be alluring early on , they do n't guarantee long-term benefits for your health and weight . a few simple guidelines , though , can help differentiate between a diet that is beneficial in maintaining long-term health , and one that only offers temporary weight changes . here 's the first tipoff : if a diet focuses on intensely cutting back calories or on cutting out entire food groups , like fat , sugar , or carbohydrates , chances are it 's a fad diet . and another red flag is ritual , when the diet in question instructs you to only eat specific foods , prescribed combinations , or to opt for particular food substitutes , like drinks , bars , or powders . the truth is shedding pounds in the long run simply does n't have a quick-fix solution . not all diet crazes tout weight loss . what about claims of superfoods , cleanses , and other body-boosting solutions ? marketing emphasizes the allure of products associated with ancient and remote cultures to create a sense of mysticism for consumers . while so-called superfoods , like blueberries or açaí , do add a powerful punch of nutrients , their super transformative qualities are largely exaggeration . they are healthy additions to a balanced diet , yet often , they 're marketed as part of sugary drinks or cereals , in which case the negative properties outweight the benefits . cleanses , too , may be great in moderation since they can assist with jumpstarting weight loss and can increase the number of fresh fruits and vegetables consumed daily . scientifically speaking , though , they 've not yet been shown to have either a long-term benefit or to detox the body any better than the natural mechanisms already in place . everywhere we look , we 're offered solutions to how we can look better , feel fitter , and generally get ahead . food is no exception , but advice on what we should eat is best left to the doctors and nutritionists who are aware of our individual circumstances . diets and food fads are n't inherently wrong . circumstantially , they might even be right , just not for everyone all of the time .
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a few simple guidelines , though , can help differentiate between a diet that is beneficial in maintaining long-term health , and one that only offers temporary weight changes . here 's the first tipoff : if a diet focuses on intensely cutting back calories or on cutting out entire food groups , like fat , sugar , or carbohydrates , chances are it 's a fad diet . and another red flag is ritual , when the diet in question instructs you to only eat specific foods , prescribed combinations , or to opt for particular food substitutes , like drinks , bars , or powders .
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which of the following is a possible characteristic of a fad-diet ?
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i was walking my mountain the other day , and i was feeling really at home with the forest . and i was so grateful to it for showing me that forests are built on relationships which form networks , like these beautiful river networks . and i thought , `` wow , forests are just like human families . '' and i was so taken by the beauty of this idea that i fell and i crashed down on the ground , and i hit my head on this new stump . and i was so angry ! then , i was so heartbroken because there was a whole family of trees cut down . thing is , where i 'm from in western canada , there 's clearcuts like this hidden everywhere , and it was n't until google earth starting sending images , like this , that we realized the whole world was wiping its noses on our old-growth forests . did you know that deforestation like this around the world causes more greenhouse gas emissions than all the trains , planes and automobiles combined ? yeah , i 'm really upset about this , but i 'm also really hopeful because i 've also discovered in my research that forest networks are organized in the same way as our own neural networks and our social networks . and i believe that if we can learn to integrate these into a whole that we can change this dangerous pathway of global warming because i believe we are wired for healing . so , here 's the science : the most ancient of these networks is this below-ground fungal network , or mushroom network . and it evolved over a billion years ago to allow organisms to migrate from the ocean onto the land . and eventually , they got together with plants in this symbiosis . and this allowed plants to photosynthesize , pulling co2 , which is our biggest greenhouse gas , out of the atmosphere and giving off oxygen , which allows us to breathe and actually allowed humans to eventually evolve . now , we call this symbiosis a mycorrhiza , myco for fungus , rrhiza for root . so , the fungus and root get together , and they trade for mutual benefit . now , all trees in all forests all over the world depend on these mycorrhizas for their very survival . they ca n't live without them . and the way it works is that a seed falls on the forest floor , it germinates , it sends a root down into the soil , and it starts sending out chemical signals to the fungi to grow towards the root . and the fungus communicates back with its own signals , and it says to the root , 'you need to grow towards me and branch and soften . ' and so by this communication , they grow together into this magical symbiosis . and the way that symbiosis works is the plant takes its hard-earned carbon from photosynthesis and brings it to the fungus because the fungus ca n't photosynthesize . and the fungus takes nutrients and water it gathers from the soil , where plant roots ca n't grow , and they give it to the plant . and so they 're both benefiting in this cooperation . now , as the fungus grows through the soil , it starts linking plant and plant and tree and tree together until the whole forest is linked together . did you know that a single tree can be literally linked up to hundreds of other trees as far as the eye can see ? and as you 're walking through the forest , what you see , the trees , the roots , the mushrooms , are just the tip of the iceberg . under a single footstep , there are 300 miles of fungal cells stacked end on end moving stuff around . and if you could look down into the ground , it would be like this super highway with cars going everywhere . now , all networks are made of nodes and links . in forests , those nodes would be trees and the links fungi . it 's kind of like in your facebook network , where nodes would be friends and links would be your friendships . now , we all know that some of those nodes , or friends , are busier than others , like that friend who is always sending out group messages . well , it 's the same in forests , and these nodes in forests , we call them hubs , they 're the big trees in the forests with roots going everywhere . now , we also have learned that the systems organized around these hubs , these big old trees , so in forests , that 's where the regeneration occurs . in your facebook network , that might be how parties are organized , around that hub that 's always sending out the group messages . we call those hubs in forests mother trees ; they 're the big old trees in the forest . and they fix the carbon in their leaves , and they send it down through their massive trunks and into the networks all around them that are linked up to all the other trees and seedlings , the young ones , and they start sending that carbon everywhere . the more those seedlings are stressed out , maybe from drought or shade , the more the mother tree sends to them . it 's kind of like in your families , where if you 're kind of stressed out , mom and dad kick in and help you out a bit more , right ? well , it 's the same in forests . the other thing that we 've recently discovered is that mother trees will preferentially send more signals to her own kids , her own children . and then , this way she helps them do better , and then they survive more , and then they can pass their genes on to future generations . so , how natural selection works . now , the way these forests are organized makes them both resilient and vulnerable . they 're resilient because there 's many mother trees , and there 's many fungal species linking them together . and that network is really hard to break . it 's pretty darn tough . but of course , we humans have figured out how to do that . and what we do is we take out the mother trees . and maybe taking one out wo n't make much difference but when you take more and more and more and clearcut and more and more and more that it can cause the system to collapse and fall down , like dominoes . and we can cross tipping points and cause more forest death and more global warming , and we 're doing that . so what we do , our choices we make , can lead us towards global heatlh or global sickness . we do have choices . and i 'm going to leave you with four ideas that i think are worth spreading . first one : to love the forest you have to go spend time in it . go be in the forest , connect with it . and then you 'll fight hard enough to protect them . second : learn how they work . learn how those networks link things together in organized forests . and to do that , you got ta go out there take risks , make mistakes . third : protect forests . they need you to do that because they ca n't do it themselves . they 're stuck in one spot . they ca n't run away from humans , and they ca n't run away from global warming . they need you . and finally , and most importantly , use your own very clever , brilliant , neural and social networks to create amazing messages , and spread the word that forests are worth saving because you 're worth saving , and i believe that together we 're all wired for healing .
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so , how natural selection works . now , the way these forests are organized makes them both resilient and vulnerable . they 're resilient because there 's many mother trees , and there 's many fungal species linking them together .
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mycorrhizal networks are organized in such a way that forests are both resilient and vulnerable at the same time . why are forests resilient , and what can we do to ensure they remain that way ?
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so this is one of our glove-boxes . yeah , if you just look to the right of the glove-box you ’ ll see that we ’ ve got these air locks and basically what you do is you put whatever it is you want to take into the box in there and then you evacuate it and then you refill it with dry , oxygen-free nitrogen so then you can take compounds which react with air and moisture into the box safely and store them . so this is a bit like what you see pictures of a nuclear industry when you ’ ve got people handling things . ok so next up is uranium , which is my favourite actinide , it ’ s the one i handle in the lab , it ’ s also the bogeyman of the periodic table , i think . as soon as you say uranium to people , people start going “ ooh , not sure about that. ” this is the bogeyman . this is uranium turnings . you see they have a sort of dull appearance because when they are cleaned up they are really very reactive , and they react with oxygen extremely quickly , but if you acid-treat them with concentrated nitric acid you get really beautiful gleaming surfaces but it doesn ’ t hang around very long . uranium is the basis of much of nuclear power and it exists in two isotopes , that ’ s two atoms of different weight , there ’ s uranium-238 which is the most abundant one and the other , uranium-235 which is the one which , when irradiated with neutrons will split in half and release nuclear energy and a lot of work has been done , or was done in during the second world war on the separation of these isotopes of uranium and , including the construction of the biggest mass spectrometers that had ever been made . and , fortunately the separation of uranium isotopes is really very difficult which is why it is only very large and rich countries have been able to afford to make nuclear weapons . this is just oil sat on the top so just like we had to have oil to protect the potassium we also need oil to protect the uranium turnings . if you really finely divide uranium turnings they are pyrophoric which means they burst into flames in the air , just spontaneously . but it ’ s actually a really interesting element to deal with . it ’ s got a wide variety of oxidation states , and if you use it in its depleted form it ’ s actually relatively safe to handle in the laboratory . now , depleted material only contains a very small quantity of fissile uranium which is used in bombs and nuclear reactors , about 0.2 of a percent . it actually means that the problem with handling depleted uranium is not the radioactivity , although you have to make provision for this , the real problem is that it is highly poisonous and about half a gram would kill you in a very short period of time because it attacks your liver , very effectively . this is uranium tetrachloride . it ’ s solvent free , it ’ s a nice free-flowing emerald green powder and if you dissolve this up in solvents like thf , you get beautiful green solutions from it . and here ’ s another form of uranium . so this is uranyl dichloride which has got two organic molecules co-ordinated to it as well . that ’ s this beautiful yellow colour . so , once you ’ ve removed the uranium-235 you ’ re still left with a very large amount , 99-point , more than 99 % of the original mass of your uranium is uranium-238 , which you have removed most but not all of the uranium-235 and this is so-called depleted uranium which is some of the densest material you can get . and so it is used where you want something very heavy that ’ s not too large . so for example , it ’ s used in the counterweights that people put in aeroplanes and large aeroplanes to balance the plane because you can use , it takes up only a small volume of space . we have to keep it safe and secure in a safe . and we have to fill out huge amounts of paperwork , many-a-forest has been chopped down for this paperwork i ’ m sure , but it ’ s all very important because you have to be certain that when handling depleted uranium compounds that you are not going to end up poisoning anybody and you are not going to end up getting radioactive compounds all over the place . so we have log books and we have to record how much we use and when and how we dispose of it . we have detectors which we have to sweep the lab . well a lot of people usually start off with “ i imagine you glow in the dark , ” which if i could do that i ’ d have passed away a long time before that point . yeah , it ’ s the bogeyman-thing again , a lot of people are quite sort of surprised or you know sort of shocked to hear that you ’ re handling this stuff but actually it ’ s just like most other chemicals on the periodic table and once you get past the ‘ bogeyman image ’ of it , it ’ s actually a very interesting element to work with . most metal or metalloid elements do look like this . it ’ s just that the number of electrons they ’ ve got , the number of electrons they take or they get rid of , is what defines their chemistry . and is that not dangerous ? you know uranium has this reputation of being so dangerous . are you not putting us in danger by holding that there ? no , this is depleted uranium , so there is about 0.2 % of this is what you would consider fissile . the rest of it is not radioactive . so it ’ s all quite toxic , but you ’ d have your work cut out to eat this stuff because it ’ s extremely hard .
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as soon as you say uranium to people , people start going “ ooh , not sure about that. ” this is the bogeyman . this is uranium turnings . you see they have a sort of dull appearance because when they are cleaned up they are really very reactive , and they react with oxygen extremely quickly , but if you acid-treat them with concentrated nitric acid you get really beautiful gleaming surfaces but it doesn ’ t hang around very long .
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which are the two principal isotopes of uranium that are present in nature ?
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translator : andrea mcdonough reviewer : morton bast i 'm a mechanical engineering professor at the university of pennsylvania , and my favorite hobby is photography . and as i travel around the world , i love taking photographs like these , so i can remember all the beautiful and interesting things that i 've seen . but what i ca n't do is record and share how these objects feel to touch . and that 's kind of surprising , because your sense of touch is really important . it 's involved in every physical interaction you do every day , every manipulation task , anything you do in the world . so the sense of touch is actually pretty interesting . it has two main components . the first is tactile sensations , things you feel in your skin . and the second is kinesthetic sensations . this has to do with the position of your body and how it 's moving , and the forces you encounter . and you 're really good at incorporating both of these types of sensations together to understand the physical interactions you have with the world and understand as you touch a surface : is it a rock , is it a cat , is it a bunny , what is it ? and so , as an engineer , i 'm really fascinated and i have a lot of respect for how good people are with their hands . and i 'm intrigued and curious about whether we could make technology better by doing a better job at leveraging the human capability with the sense of touch . could i improve the interfaces to computers and machines by letting you take advantage of your hands ? and indeed , i think we can , and that 's at the core of a field called haptics , and this is the area that i work in . it 's all about interactive touch technology . and the way it works is , as you move your body through the world , if , as an engineer , i can make a system that can measure that motion , and then present to you sensations over time that kind of make sense , that match up with what you might feel in the real world , i can fool you into thinking you 're touching something even though there 's nothing there . so here are three examples and these are all done from research in my lab at penn . the first one is all about that same problem that i was showing you : how can we capture how objects feel and recreate those experiences ? so the way we solve this problem is by creating a hand-held tool that has many different sensors inside . it has a force sensor , so we can tell how hard you 're pushing ; it has motion tracking , so we can tell exactly where you 've moved it ; and it has a vibration sensor , an accelerometer , inside , that detects the shaking back and forth of the tool that lets you know that 's a piece of canvas and not a piece of silk or something else . then we take the data we record from these interactions . here 's ten seconds of data . you can see how the vibrations get larger and smaller , depending on how you move . and we make a mathematical model of those relationships and program them into a tablet computer so that when you take the stylus and go and touch the screen , that voice-coil actuator in the white bracket plays vibrations to give you the illusion that you 're touching the real surface , just like if you touched , dragged back and forth , on the real canvas . we can create very compelling illusions . we can do this for all kinds of surfaces and it 's really a lot of fun . we call it haptography -- haptic photography . and i think it has potential benefits in all sorts of areas like online shopping , maybe interactive museum exhibits , where you 're not supposed to touch the precious artifacts , but you always want to . the second example i want to tell you about comes from a collaboration i have with dr. margrit maggio at the penn dental school . part of her job is to teach dental students how to tell where in a patient 's mouth there are cavities . of course they look at x-rays , but a large part of this clinical judgment comes from what they feel when they touch your teeth with a dental explorer . you 've all had this happen , they go across . what they 're feeling for is if the tooth is really hard , then it 's healthy , but if it 's kind of soft and sticky , that 's a signal that the enamel is starting to decay . these types of judgments are hard for a new dental student to make , because they have n't touched a lot of teeth yet . and you want them to learn this before they start practicing on real human patients . so what we do is add an accelerometer on to the dental explorer , and then we record what dr. maggio feels as she touches different extracted teeth . and we can play it back for you as a video with a touch track -- not just a sound track , but also a touch track , that you can feel by holding that repeating tool . you feel the same things the dentist felt when they did the recording , and practice making judgments . so here 's a sample one . here 's a tooth that looks kind of suspicious , right ? it has all those brown stains . you might be thinking , `` we should definitely put a filling in this tooth . '' but if you pay attention to how it feels , all the surfaces of this tooth are hard and healthy , so this patient does not need a filling . and these are exactly the kind of judgments doctors make every day and i think this technology we 've invented has a lot of potential for many different things in medical training , because it 's really simple and it does a great job at recreating what people feel through tools . i think it could also help make games more interactive and fun and more realistic in the sensations that you feel . the last example i want to tell you about is again about human movement . so if any of you have ever learned sports , how do you get good at something like surfing ? you practice . you practice some more and more , right ? making small corrections , maybe getting some input from a coach , learning how to improve your motions . i think we could use computers to help make that process more efficient and more fun . and so here , for example , if i have six different arm movements that i want you to learn , you come into my lab at penn and try out our system . we use a kinect to measure your motions , we show graphics on the screen , and then we also give you touch cues , haptic feedback on your arm , delivered by these haptic arm bands which have motors inside , and guide you as you move . so , if we put it together , as you 're trying to track this motion , if you deviate -- say , maybe , your arm is a little too high -- we turn on the motors right there on the skin to let you know you should move down , almost like a coach gently guiding you and helping you master these movements more quickly and make more precise corrections . we developed this system for use in stroke rehabilitation , but i think there are a lot of applications , like maybe dance training or all sorts of sports training as well . so now you know a little bit about the field of haptics , which i think you 'll hear more about in the coming years . i 've shown you three examples . i just want to take a moment to acknowledge the great students who work with me in my lab at penn and my collaborators . they 're a great group . i also want to thank you for your kind attention . ( applause )
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and indeed , i think we can , and that 's at the core of a field called haptics , and this is the area that i work in . it 's all about interactive touch technology . and the way it works is , as you move your body through the world , if , as an engineer , i can make a system that can measure that motion , and then present to you sensations over time that kind of make sense , that match up with what you might feel in the real world , i can fool you into thinking you 're touching something even though there 's nothing there .
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what 's an example of a place the technology that kuchenbecker is developing could be used ?
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it starts with a cough , or a wheeze . soon , your chest feels tight . your breathing speeds up and gets shallower , making you feel short of breath . these are common symptoms of an asthma attack . around the world , more than 300 million people suffer from asthma , and around 250,000 people die from it each year . but why do people get asthma and how can this disease be deadly ? asthma affects the respiratory system , particularly the smaller airways , such as the bronchi and bronchioles . these airways have an inner lining called the mucosa that 's surrounded by a layer of smooth muscle . in people with asthma , the airways are chronically inflamed , which can make them hyper-responsive to certain triggers . some of the many asthma triggers include tobacco smoke , pollen , dust , fragrances , exercise , cold weather , stress , and even the common cold . when people with asthma are exposed to these triggers , an asthma attack , or exacerbation , can occur . but how exactly do such everyday factors lead to an asthma attack ? if an asthmatic is exposed to a trigger , the smooth rings of muscle that circle the small airways in their lungs contract and become narrow . simultaneously , the trigger worsens inflammation , causing the mucosal lining to become more swollen and secrete more mucus . under normal conditions , the body uses this mucus to trap and clear particles , like pollen or dust , but during an asthma attack , it blocks the narrowed airways , making it even harder to breathe . these effects lead to this symptoms of asthma . smooth muscle constriction results in the feeling of chest tightness . excess mucus and increased inflammation can cause coughing . and the wheezing noise ? that happens because as the airways constrict , air whistles as it passes through the narrowed space . these symptoms may make a person feel like they 're running out of air . yet counterintuitively , during an asthma attack , the inflammation can make it harder to exhale than inhale . over time , this leads to an excess of air in the lungs , a phenomenon known as hyperinflation . the trapping of air inside the lungs forces the body to work harder to move air in and out of them . over time , this can lead to reduced oxygen delivery to the body 's organs and tissues . sometimes , in untreated severe asthma attacks , the body ca n't keep up , which can lead to death from lack of oxygen . so how do we prevent these uncomfortable and potentially fatal attacks in people who have asthma ? one way is to reduce the presence of triggers . unfortunately , the world is an unpredictable place and exposure to triggers ca n't always be controlled . this is where inhalers , the primary treatment for asthma , come in . these medications help asthmatics both control and prevent their asthma symptoms . inhalers transport medication along the affected airways using a liquid mist or fine powder to treat the problem at its source . they come in two forms . there are reliever medications , which treat symptoms immediately and contain beta-agonists . beta-agonists relax constricted muslces , allowing the airways to widen so more air can travel into and out of the lungs . the other form of inhalers serve as preventive medications , which treat asthma symptoms over the long term , and contain corticosteroids . corticosteroids reduce airway sensitivity and inflammation , so asthma can be kept under control . they 're also crucial in preventing long-term damage from chronic inflammation , which can cause scarring of the airways . inhalers are known to be very effective , and have helped many people live better lives . although we 've come a long way in improving how we treat and diagnose asthma , we still do n't know its exact causes . we currently believe that a combination of genetic and environmental factors play a role , potentially acting during early childhood . recent research has even linked poverty to asthma incidents . this may be due to reasons ranging from exposure to additional pollutants and environmental irritants to difficulties in obtaining medical care or treatment . as our understanding of asthma improves , we can continue to find better ways to keep people 's airways happy and healthy .
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your breathing speeds up and gets shallower , making you feel short of breath . these are common symptoms of an asthma attack . around the world , more than 300 million people suffer from asthma , and around 250,000 people die from it each year . but why do people get asthma and how can this disease be deadly ?
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how many asthma-related deaths are estimated to occur annually around the world ?
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the victory of the underdog over the favored team . the last minute penalty shot that wins the tournament . the high-energy training montages . many people love to glorify victory on the playing field , cheer for favorite teams , and play sports . but here 's a question : should we be so obsessed with sports ? is playing sports actually as good for us as we make it out to be , or just a fun and entertaining pastime ? what does science have to say ? first of all , it 's well accepted that exercise is good for our bodies and minds , and that 's definitely true . exercising , especially when we 're young , has all sorts of health benefits , like strengthening our bones , clearing out bad cholesterol from our arteries , and decreasing the risk of stroke , high blood pressure , and diabetes . our brains also release a number of chemicals when we workout , including endorphins . these natural hormones , which control pain and pleasure responses in the cental nervous system , can lead to feelings of euphoria , or , what 's often called , a runner 's high . increased endorphins and consistent physical activity in general can sharpen your focus and improve your mood and memory . so does that mean we get just as much benefit going to the gym five days a week as we would joining a team and competing ? well , here 's where it gets interesting : because it turns out that if you can find a sport and a team you like , studies show that there are all sorts of benefits that go beyond the physical and mental benefits of exercise alone . some of the most significant are psychological benefits , both in the short and long term . some of those come from the communal experience of being on a team , for instance , learning to trust and depend on others , to accept help , to give help , and to work together towards a common goal . in addition , commitment to a team and doing something fun can also make it easier to establish a regular habit of exercise . school sport participation has also been shown to reduce the risk of suffering from depression for up to four years . meanwhile , your self-esteem and confidence can get a big boost . there are a few reasons for that . one is found in training . just by working and working at skills , especially with a good coach , you reinforce a growth mindset within yourself . that 's when you say , `` even if i ca n't do something today , i can improve myself through practice and achieve it eventually . '' that mindset is useful in all walks of life . and then there 's learning through failure , one of the most transformative , long-term benefits of playing sports . the experience of coming to terms with defeat can build the resilience and self-awareness necessary to manage academic , social , and physical hurdles . so even if your team is n't winning all the time , or at all , there 's a real benefit to your experience . now , not everyone will enjoy every sport . perhaps one team is too competitive , or not competitive enough . it can also take time to find a sport that plays to your strengths . that 's completely okay . but if you spend some time looking , you 'll be able to find a sport that fits your individual needs , and if you do , there are so many benefits . you 'll be a part of a supportive community , you 'll be building your confidence , you 'll be exercising your body , and you 'll be nurturing your mind , not to mention having fun .
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and then there 's learning through failure , one of the most transformative , long-term benefits of playing sports . the experience of coming to terms with defeat can build the resilience and self-awareness necessary to manage academic , social , and physical hurdles . so even if your team is n't winning all the time , or at all , there 's a real benefit to your experience .
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experiencing defeat as an athlete can be tough , but critical for building :
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have you ever seen static electricity cause a spark of light ? what is that spark ? what about lightning , the northern lights , or the tail of a comet ? all of those things , and many others , in fact 99.9 % of the universe , are made of plasma . plasma is a state of matter drastically different from the more familiar forms . take ice , for example . ice , a solid , melts to become water , a liquid , which , when heated , vaporizes into steam , a gas . continued heating of the steam at a high enough temperature causes the water molecules in it to separate into freely roaming hydrogen and oxygen atoms . with a little more heat , the ionization process occurs and the negatively charged electrons escape the atoms , leaving behind positively charged ions . this mixture of freely roaming negative and positive charges is plasma , and at a high enough temperature , any gas can be made into one . these freely moving charged particles behave very differently from the particles in other types of matter . when a doorknob , a solid , has static electricity on it , it does n't look or behave any differently . and with the exception of a compass or other magnetic object , we rarely see matter respond to a magnetic field . but put a plasma in an electric field or magnetic field , and you 'll get a very different reaction . because plasmas are charged , electric fields accelerate them , and magnetic fields steer them in circular orbits . and when the particles within plasma collide , or accelerated by electricity or magnetism , light is generated , which is what we see when we look at plasmas like the aurora borealis . plasmas are n't just beautiful , celestial phenomena , though . imagine a tiny cube made of normal gas with a very high voltage across it . the resulting electric field pushes some of the electrons off the atoms and accelerates them to high speeds causing the ionization of other atoms . imbedded impurities in the tiny cube of gas cause it to gain and release a precise amount of energy in the form of ultraviolet radiation . attached to each tiny cube , a fluorescent material glows with a specific color when ultraviolet light at just the right intensity reaches it . now , make a rectangle out of a million of these tiny cubes , each separately controlled by sophisticated electronics . you may be looking at one now . this is called a plasma tv . plasmas also have implications for health care . plasma chemists create highly specific plasmas that can destroy or alter targeted chemicals , thereby killing pathogenic organisms on food or hospital surfaces . plasmas are all around us , in forms that are both spectacular and practical . and in the future , plasma could be used to permanently rid landfills of their waste , efficiently remove toxins from our air and water , and provide us with a potentially unlimited supply of renewable clean energy .
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you may be looking at one now . this is called a plasma tv . plasmas also have implications for health care .
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what applications of plasma are possible ?
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in the third act of `` swan lake , '' the black swan pulls off a seemingly endless series of turns , bobbing up and down on one pointed foot and spinning around , and around , and around 32 times . it 's one of the toughest sequences in ballet , and for those thirty seconds or so , she 's like a human top in perpetual motion . those spectacular turns are called fouettés , which means `` whipped '' in french , describing the dancer 's incredible ability to whip around without stopping . but while we 're marveling at the fouetté , can we unravel its physics ? the dancer starts the fouetté by pushing off with her foot to generate torque . but the hard part is maintaining the rotation . as she turns , friction between her pointe shoe and the floor , and somewhat between her body and the air , reduces her momentum . so how does she keep turning ? between each turn , the dancer pauses for a split second and faces the audience . her supporting foot flattens , and then twists as it rises back onto pointe , pushing against the floor to generate a tiny amount of new torque . at the same time , her arms sweep open to help her keep her balance . the turns are most effective if her center of gravity stays constant , and a skilled dancer will be able to keep her turning axis vertical . the extended arms and torque-generating foot both help drive the fouetté . but the real secret and the reason you hardly notice the pause is that her other leg never stops moving . during her momentary pause , the dancer 's elevated leg straightens and moves from the front to the side , before it folds back into her knee . by staying in motion , that leg is storing some of the momentum of the turn . when the leg comes back in towards the body , that stored momentum gets transferred back to the dancer 's body , propelling her around as she rises back onto pointe . as the ballerina extends and retracts her leg with each turn , momentum travels back and forth between leg and body , keeping her in motion . a really good ballerina can get more than one turn out of every leg extension in one of two ways . first , she can extend her leg sooner . the longer the leg is extended , the more momentum it stores , and the more momentum it can return to the body when it 's pulled back in . more angular momentum means she can make more turns before needing to replenish what was lost to friction . the other option is for the dancer to bring her arms or leg in closer to her body once she returns to pointe . why does this work ? like every other turn in ballet , the fouetté is governed by angular momentum , which is equal to the dancer 's angular velocity times her rotational inertia . and except for what 's lost to friction , that angular momentum has to stay constant while the dancer is on pointe . that 's called conservation of angular momentum . now , rotational inertia can be thought of as a body 's resistance to rotational motion . it increases when more mass is distributed further from the axis of rotation , and decreases when the mass is distributed closer to the axis of rotation . so as she brings her arms closer to her body , her rotational inertia shrinks . in order to conserve angular momentum , her angular velocity , the speed of her turn , has to increase , allowing the same amount of stored momentum to carry her through multiple turns . you 've probably seen ice skaters do the same thing , spinning faster and faster by drawing in their arms and legs . in tchaikovsky 's ballet , the black swan is a sorceress , and her 32 captivating fouettés do seem almost supernatural . but it 's not magic that makes them possible . it 's physics .
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that 's called conservation of angular momentum . now , rotational inertia can be thought of as a body 's resistance to rotational motion . it increases when more mass is distributed further from the axis of rotation , and decreases when the mass is distributed closer to the axis of rotation .
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what is rotational inertia ?
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so you just strained a muscle and the inflammation is unbearable . you wish you had something ice-cold to dull the pain , but to use an ice pack , you would have had to put it in the freezer hours ago . fortunately , there 's another option . a cold pack can be left at room temperature until the moment you need it , then just snap it as instructed and within seconds you 'll feel the chill . but how can something go from room temperature to near freezing in such a short time ? the answer lies in chemistry . your cold pack contains water and a solid compound , usually ammonium nitrate , in different compartments separated by a barrier . when the barrier is broken , the solid dissolves causing what 's known as an endothermic reaction , one that absorbs heat from its surroundings . to understand how this works , we need to look at the two driving forces behind chemical processes : energetics and entropy . these determine whether a change occurs in a system and how energy flows if it does . in chemistry , energetics deals with the attractive and repulsive forces between particles at the molecular level . this scale is so small that there are more water molecules in a single glass than there are known stars in the universe . and all of these trillions of molecules are constantly moving , vibrating and rotating at different rates . we can think of temperature as a measurement of the average motion , or kinetic energy , of all these particles , with an increase in movement meaning an increase in temperature , and vice versa . the flow of heat in any chemical transformation depends on the relative strength of particle interactions in each of a substance 's chemical states . when particles have a strong mutual attractive force , they move rapidly towards one another , until they get so close , that repulsive forces push them away . if the initial attraction was strong enough , the particles will keep vibrating back and forth in this way . the stronger the attraction , the faster their movement , and since heat is essentially motion , when a substance changes to a state in which these interactions are stronger , the system heats up . but our cold packs do the opposite , which means that when the solid dissolves in the water , the new interactions of solid particles and water molecules with each other are weaker than the separate interactions that existed before . this makes both types of particles slow down on average , cooling the whole solution . but why would a substance change to a state where the interactions were weaker ? would n't the stronger preexisting interactions keep the solid from dissolving ? this is where entropy comes in . entropy basically describes how objects and energy are distributed based on random motion . if you think of the air in a room , there are many different possible arrangements for the trillions of particles that compose it . some of these will have all the oxygen molecules in one area , and all the nitrogen molecules in another . but far more will have them mixed together , which is why air is always found in this state . now , if there are strong attractive forces between particles , the probability of some configurations can change even to the point where the odds do n't favor certain substances mixing . oil and water not mixing is an example . but in the case of the ammonium nitrate , or other substance in your cold pack , the attractive forces are not strong enough to change the odds , and random motion makes the particles composing the solid separate by dissolving into the water and never returning to their solid state . to put it simply , your cold pack gets cold because random motion creates more configurations where the solid and water mix together and all of these have even weaker particle interaction , less overall particle movement , and less heat than there was inside the unused pack . so while the disorder that can result from entropy may have caused your injury in the first place , its also responsible for that comforting cold that soothes your pain .
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but in the case of the ammonium nitrate , or other substance in your cold pack , the attractive forces are not strong enough to change the odds , and random motion makes the particles composing the solid separate by dissolving into the water and never returning to their solid state . to put it simply , your cold pack gets cold because random motion creates more configurations where the solid and water mix together and all of these have even weaker particle interaction , less overall particle movement , and less heat than there was inside the unused pack . so while the disorder that can result from entropy may have caused your injury in the first place , its also responsible for that comforting cold that soothes your pain .
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the main driving force that results in cold packs working is :
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translator : andrea mcdonough reviewer : bedirhan cinar the human eye is one of the most powerful machines on the planet . it 's like a 500 megapixel camera that can run in bright light , in near darkness , and even under water , though not real well . it communicates to our brains so much about the world . our eyes are how we find partners , how we understand the people around us , how we read , and how we watch game shows on tv where people get knocked into cold water by padded wrecking balls . yup , the human eye is pretty neat , and we 're lucky enough to have two of them . but , there are things that , despite looking really hard , we still ca n't quite see . for example , you can watch a horse galloping , but your eyes ca n't keep up with its fast-moving hooves enough to figure out whether all four feet are ever off the ground simultaneously . for these types of questions , we need cameras . about 150 years ago , the photographer eadweard muybridge used one to solve the galloping horse mystery . using careful photography , muybridge proved that at certain points as it gallops , a horse really is flying . `` look , ma ! no hooves ! '' since then , photography has found its way into all aspects of math and science . it enhances our understanding of a world we thought we could already see , but it 's one which we really need help to see a little better . it 's not always a matter of the world moving by too quickly for our eyes to process . sometimes cameras can help us see matter or movements that are too small for the naked eye . botanists use multiple photographs to show the life cycle of plants and how flowers turn over the course of a few hours to follow the sun in what is called phototropism , growing towards the light . mathematicians have used photos to look at where in the twists and turns of a whip the crack sound comes when the whip is breaking the sound barrier . meteorologists and environmental scientists show the growth of major hurricanes and the recession over the years of many of the world 's glaciers . slow-motion film or high-speed photography have shown us the beating of a hummingbird 's wings and the course of a bullet through its target . in one project , cadavers , that 's dead bodies , were frozen and sliced into thousands of wafer-thin discs . the discs were photographed to produced animated movies that allow a viewer to travel up and down the skeleton , and into the flesh , and through the bones , and the veins , and , perhaps i should have suggested you do n't watch this during dinner , my bad . in classrooms today , the camera , now present in just about every phone and computer , allows the youngest scientists to observe the world around them , to document it , and to share their findings online . whether it 's the change of seasons or the growth of the germinating seed , cameras are allowing us to see a beautiful world through new eyes .
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slow-motion film or high-speed photography have shown us the beating of a hummingbird 's wings and the course of a bullet through its target . in one project , cadavers , that 's dead bodies , were frozen and sliced into thousands of wafer-thin discs . the discs were photographed to produced animated movies that allow a viewer to travel up and down the skeleton , and into the flesh , and through the bones , and the veins , and , perhaps i should have suggested you do n't watch this during dinner , my bad .
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what are cadavers ?
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his face is recognized all over the world . the young medical student who became a revolutionary icon . but was che guevara a heroic champion of the poor or a ruthless warlord who left a legacy of repression ? order , order . hey , where have i seen that guy before ? ahem , your honor , this is ernesto che guevara . in the early 1950s , he left behind a privileged life as a medical student in argentina to travel through rural latin america . the poverty and misery he witnessed convinced him that saving lives required more than medicine . so he became a terrorist seeking to violently overthrow the region 's governments . what ? the region 's governments were brutal oligarchies . colonialism may have formally ended , but elites still controlled all the wealth . american corporations bought up land originally seized from indigenous people and used it for profit and export , even keeping most of it uncultivated while locals starved . could n't they vote to change that ? oh , they tried , your honor . in 1953 , che came to guatemala under the democratically-elected government of president árbenz . árbenz passed reforms to redistribute some of this uncultivated land back to the people while compensating the landowners . but he was overthrown in a cia-sponsored coup . the military was protecting against the seizure of private property and communist takeover . they were protecting corporate profits and che saw that they would use the fear of communism to overthrow any government that threatened those profits . so he took the lessons of guatemala with him to mexico . there , he met exiled cuban revolutionaries and decided to help them liberate their country . you mean help fidel castro turn a vibrant cuba into a dictatorship . dictatorship was what cuba had before the revolution . fulgencio batista was a tyrant who came to power in a military coup . he turned havana into a luxury playground for foreigners while keeping cubans mired in poverty and killing thousands in police crackdowns . even president kennedy called it the worst example of `` economic colonization , humiliation , and exploitation in the world . '' whatever batista 's faults , it ca n't compare to the totalitarian nightmare castro would create . forced labor camps , torture of prisoners , no freedom to speak or to leave . but this is n't the trial of fidel castro , is it ? che guevara was instrumental in helping castro seize power . as a commander in his guerilla army , he unleashed a reign of terror across the countryside , killing any suspected spies or dissenters . he also helped peasants build health clinics and schools , taught them to read , and even recited poetry to them . his harsh discipline was necessary against a much stronger enemy who did n't hesitate to burn entire villages suspected of aiding the rebels . let 's not forget that the new regime held mass executions and killed hundreds of people without trial as soon as they took power in 1959 . the executed were officials and collaborators who had tormented the masses under batista . the people supported this revolutionary justice . which people ? an angry mob crying for blood does not a democracy make . and that 's not even mentioning the forced labor camps , arbitrary arrests , and repression of lgbt people that continued long after the revolution . there 's a reason people kept risking their lives to flee , often with nothing but the clothes on their backs . so was that all this che brought to cuba ? just another violent dictatorship ? not at all . he oversaw land redistribution , helped established universal education , and organized volunteer literacy brigades that raised cuba 's literacy rate to 96 % , still one of the highest in the world . which allowed the government to control what information everyone received . guevara 's idealistic incompetence as finance minister caused massive drops in productivity when he replaced worker pay raises with moral certificates . he suppressed all press freedom , declaring that newspapers were instruments of the oligarchy . and it was he who urged castro to host soviet nuclear weapons , leading to the cuban missile crisis that brought the world to the brink of destruction . he was a leader , not a bureaucrat . that 's why he eventually left to spread the revolution abroad . which did n't go well . he failed to rally rebels in the congo and went to bolivia even when the soviets disapproved . the bolivian government , with the help of the cia , was able to capture and neutralize this terrorist in 1967 , before he could do much damage . while doing plenty of damage themselves in the process . so that was the end of it ? not at all . as che said , the revolution is immortal . he was publicly mourned in cities all over the world . not by the cubans who managed to escape . and his story would inspire young activists for generations to come . ha . a trendy symbol of rebellion for those who never had to live under his regime . symbols of revolution may become commodified , but the idea of a more just world remains . maybe , but i 'm not sharing my coffee . che guevara was captured and executed by government forces in bolivia . his remains would not be found for another 30 years . but did he die a hero or had he already become a villain ? and should revolutions be judged by their ideals or their outcomes ? these are the questions we face when we put history on trial .
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oh , they tried , your honor . in 1953 , che came to guatemala under the democratically-elected government of president árbenz . árbenz passed reforms to redistribute some of this uncultivated land back to the people while compensating the landowners .
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what was president arbenz ’ s program in guatemala ?
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... and i 'm scratching , and i like to hide . oh , i am such a good spider . i will turn this way , and i will , let 's see ... i will hide now . ah , with a scratch scratch scratch scratch scratch scratch scratch ! and i will flatten myself like this ! and now i 'm hiding , and i can see you . i like looking at you ... but wait a minute . if i can see you then you can see me ... meh , and it *is* a bit drafty in here , i must say . so maybe i 'm not hidden . i will turn this way . yes ? and i will – i will scratch scratch scratch scratch scratch scratch scratch scratch ! and that will bury myself again , and i will flatten my legs this time that was the problem last time – my legs were not flattened , so i flat – no ! but i still bury– oh hon hon hon hon honn hon hon honnnn ! here is the secret key ! i can not be you , that they you can not see me ... i am hidden !
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... and i 'm scratching , and i like to hide . oh , i am such a good spider .
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which point of view is least used ?
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mysteries of vernacular : jade , a hard , typically green stone . until relatively recently , gemstones were believed to have magical , medicinal properties , and nothing was more effective at treating a kidney disorder than jade . in the 16th century , the spanish returned from the new world with the mineral in their cargo holds and christened it , `` piedra de la ijada , '' or loin stone . it quickly became popular throughout europe , both as a cure for internal ailments and as a decorative ornament and was renamed jade by the french , a word that was borrowed by the english and remains in use to this day . in the 19th century , french mineralogists discovered that jade was being used to describe two distinct minerals : jadeite , which takes its name from jade , and the more common nephrite , the root of which is the greek word nephros , meaning kidney . in addition to describing these two minerals , jade also has an english homonym . with roots that predate the popularity of the lustral gemstone , jade was used to refer to either a disreputable woman or a broken-down horse . thus , the word jaded , meaning worn out or lacking enthusiasm , has nothing to do with the gemstone , and instead , comes from the archaic , equine-related definition .
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in the 19th century , french mineralogists discovered that jade was being used to describe two distinct minerals : jadeite , which takes its name from jade , and the more common nephrite , the root of which is the greek word nephros , meaning kidney . in addition to describing these two minerals , jade also has an english homonym . with roots that predate the popularity of the lustral gemstone , jade was used to refer to either a disreputable woman or a broken-down horse .
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what is the difference between a homonym and a synonym ?
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if you 've ever floated on an ocean swell , you 'll know that the sea moves constantly . zoom out , and you 'll see the larger picture : our earth , covered by 71 percent water , moving in one enormous current around the planet . this intimidating global conveyor belt has many complicated drivers , but behind it all is a simple pump that moves water all over the earth . the process is called thermohaline circulation , and it 's driven by a basic concept : the concentration gradient . let 's leave the ocean for one moment and imagine we 're in an empty room with lots of roombas sardined together in one corner . turn them all on at once and the machines glide outwards bumping into and away from each other until the room is filled with an evenly spaced distribution . the machines have moved randomly towards equilibrium , a place where the concentration of a substance is equally spread out . that 's what happens along a concentration gradient , as substances shift passively from a high , or squashed , concentration , to a lower , more comfortable one . how does this relate to ocean currents and thermohaline circulation ? thermo means temperature , and haline means salt because in the real world scenario of the sea , temperature and salinity drive the shift from high to low concentrations . let 's put you back in the ocean to see how this works . snap ! you 're transformed into a molecule of surface water , off the temperate coast of new york surrounded by a zillion rowdy others . here , the sun 's rays act as an energizer that set you and the other water molecules jostling about , bouncing off each other like the roombas did . the more you spread out , the less concentrated the water molecules at the surface become . through this passive motion , you move from a high to a lower concentration . let 's suspend the laws of physics for a moment , and pretend that your molecular self can plunge deep down into the water column . in these colder depths , the comparative lack of solar warmth makes water molecules sluggish , meaning they can sit quite still at high concentrations . no jostling here . but seeking relief from the cramped conditions they 're in , they soon start moving upwards towards the roomier situation at the surface . this is how temperature drives a shift of water molecules from high to low concentrations , towards equilibrium . but sea water is made up of more than just h2o . there are a great deal of salt ions in it as well . and like you , these guys have a similar desire for spacious real estate . as the sun warms the sea , some of your fellow water molecules evaporate from the surface , increasing the ration of salt to h2o . the crowded salt ions left behind notice that lower down , salt molecules seem to be enjoying more space . and so an invasion begins , as they too move downwards in the water column . in the polar regions , we see how this small local process effects global movement . in the arctic and antarctic , where ice slabs decorate the water 's surface , there 's little temperature difference between surface and deeper waters . it 's all pretty cold . but salinity differs , and in this scenario , that 's what triggers the action . here , the sun 's rays melt surface ice , depositing a new load of water molecules into the sea . that not only increases the proximity between you and other water molecules , leaving you vying for space again , but it also conversely dilutes the concentration of salt ions . so , down you go , riding along the concentration gradient towards more comfortable conditions . for salt ions , however , their lower concentration at the surface , acts like an advertisement to the clamoring masses of salt molecules below who begin their assent . in both temperate and polar regions , this passive motion along a concentration gradient , can get a current going . and that is the starting point of the global conveyor called thermohaline circulation . this is how a simple concept becomes the mechanism underlying one of the largest and most important systems on our planet . and if you look around , you 'll see it happening everywhere . turn on a light , and it 's there . concentration gradients govern the flow of electricity , allowing electrons squashed together in one space to travel to an area of lower concentration when a channel is opened , which you do by flipping a switch . right now , in fact , there 's some gradient action going on inside you as you breath air into your lungs letting the concentrated oxygen in that air move passively out of your lungs and into your blood stream . we know that the world is filled with complex physical problems , but sometimes the first step towards understanding them can be simple . so when you confront the magnitude of the ocean 's currents , or have to figure out how electricity works , remember not to panic . understanding can be as simple as flipping a switch .
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the machines have moved randomly towards equilibrium , a place where the concentration of a substance is equally spread out . that 's what happens along a concentration gradient , as substances shift passively from a high , or squashed , concentration , to a lower , more comfortable one . how does this relate to ocean currents and thermohaline circulation ?
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concentration gradients can be found in all systems on earth and throughout the universe . they drive much of the movement of ions , temperature , and other materials . if a concentration gradient helps explain water loss in plants , where do you think the concentration of water molecules is higher : in the air surrounding the plant ? or in the plant tissue ? why ?
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one foggy morning in 1884 , the british steamer `` rumney '' crashed into the french ship `` frigorifique . '' seeing their ship filling with water , the french crew climbed aboard the `` rumney . '' but as they sailed towards the nearest port , a silent form suddenly emerged from the fog : the abandoned `` frigorifique . '' it was too late to turn , and the impact was enough to sink the `` rumney . '' as the sailors scrambled into the lifeboats , the empty `` frigorifique '' sailed back into the fog , having seemingly taken its revenge . in reality , the french sailors had left the engines running , and the `` frigorifique '' sailed in a circle before striking the `` rumney '' and finally sinking . but its story became one of the many tales of ghost ships , unmanned vessels that apparently sail themselves . and although they 've influenced works like `` dracula '' and `` pirates of the caribbean , '' crewless ships are n't the product of ghostly spirits , just physics at work . one of the most famous ghost ships was the `` mary celeste '' found sailing the atlantic in 1872 with no one aboard , water in its hold , and lifeboats missing . the discovery of its intact cargo and a captain 's log that ended abruptly led to wild rumors and speculation . but the real culprits were two scientific phenomena : buoyancy and fluid dynamics . here 's how buoyancy works . an object placed in a liquid displaces a certain volume of fluid . the liquid in turn exerts an upward buoyant force equal to the weight of the fluid that 's been displaced . this phenomenon is called archimedes 's principle . objects that are less dense than water , such as balsa wood , icebergs , and inflatable rafts always float . that 's because the upward buoyant force is always stronger than the downward force of gravity . but for objects or ships to float when they 're made of materials , like steel , that are denser than water , they must displace a volume of water larger than their weight . normally , the water filling a ship 's hull would increase its weight and cause it to sink - just what the `` mary celeste 's '' crew feared when they abandoned ship . but the sailors did n't account for fluid dynamics . the water stopped flowing at the point of equilibrium , when it reached the same level as the hull . as it turned out , the weight of the water was n't enough to sink the ship and the `` mary celeste '' was found a few days later while the unfortunate crew never made it to shore . far stranger is the tale of `` a. ernest mills , '' a schooner transporting salt , whose crew watched it sink to the sea floor following a collision . yet four days later , it was spotted floating on the surface . the key to the mystery lay in the ship 's heavy cargo of salt . the added weight of the water in the hull made the vessel sink , but as the salt dissolved in the water , the weight decreased enough that the force of gravity became less than the buoyant force and the ship floated back to the surface . but how do we explain the most enduring aspect of ghost ship legends : multiple sightings of the same ships hundreds of miles and several years apart ? the answer lies in ocean currents , which are like invisible rivers flowing through the ocean . factors , like temperature , salinity , wind , gravity , and the coriolis effect from the earth 's rotation create a complex system of water movement . that applies both at the ocean 's surface and deep below . sailors have always known about currents , but their patterns were n't well known until recently . in fact , tracking abandoned ships was how scientists determined the shape and speed of the atlantic gyre , the gulf stream , and related currents in the first place . beginning in 1883 , the u.s. hydrographic office began collecting monthly data that included navigation hazards , like derelict ships , whose locations were reported by passing vessels . so abandoned ships may not be moved by ghost crews or supernatural curses , but they are a real and fascinating phenomenon born through the ocean and kept afloat by powerful , invisible , scientifically studied forces .
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but how do we explain the most enduring aspect of ghost ship legends : multiple sightings of the same ships hundreds of miles and several years apart ? the answer lies in ocean currents , which are like invisible rivers flowing through the ocean . factors , like temperature , salinity , wind , gravity , and the coriolis effect from the earth 's rotation create a complex system of water movement .
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how did derelict ships become a proxy for mapping ocean currents ?
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humans have been fascinated with speed for ages . the history of human progress is one of ever-increasing velocity , and one of the most important achievements in this historical race was the breaking of the sound barrier . not long after the first successful airplane flights , pilots were eager to push their planes to go faster and faster . but as they did so , increased turbulence and large forces on the plane prevented them from accelerating further . some tried to circumvent the problem through risky dives , often with tragic results . finally , in 1947 , design improvements , such as a movable horizontal stabilizer , the all-moving tail , allowed an american military pilot named chuck yeager to fly the bell x-1 aircraft at 1127 km/h , becoming the first person to break the sound barrier and travel faster than the speed of sound . the bell x-1 was the first of many supersonic aircraft to follow , with later designs reaching speeds over mach 3 . aircraft traveling at supersonic speed create a shock wave with a thunder-like noise known as a sonic boom , which can cause distress to people and animals below or even damage buildings . for this reason , scientists around the world have been looking at sonic booms , trying to predict their path in the atmosphere , where they will land , and how loud they will be . to better understand how scientists study sonic booms , let 's start with some basics of sound . imagine throwing a small stone in a still pond . what do you see ? the stone causes waves to travel in the water at the same speed in every direction . these circles that keep growing in radius are called wave fronts . similarly , even though we can not see it , a stationary sound source , like a home stereo , creates sound waves traveling outward . the speed of the waves depends on factors like the altitude and temperature of the air they move through . at sea level , sound travels at about 1225 km/h . but instead of circles on a two-dimensional surface , the wave fronts are now concentric spheres , with the sound traveling along rays perpendicular to these waves . now imagine a moving sound source , such as a train whistle . as the source keeps moving in a certain direction , the successive waves in front of it will become bunched closer together . this greater wave frequency is the cause of the famous doppler effect , where approaching objects sound higher pitched . but as long as the source is moving slower than the sound waves themselves , they will remain nested within each other . it 's when an object goes supersonic , moving faster than the sound it makes , that the picture changes dramatically . as it overtakes sound waves it has emitted , while generating new ones from its current position , the waves are forced together , forming a mach cone . no sound is heard as it approaches an observer because the object is traveling faster than the sound it produces . only after the object has passed will the observer hear the sonic boom . where the mach cone meets the ground , it forms a hyperbola , leaving a trail known as the boom carpet as it travels forward . this makes it possible to determine the area affected by a sonic boom . what about figuring out how strong a sonic boom will be ? this involves solving the famous navier-stokes equations to find the variation of pressure in the air due to the supersonic aircraft flying through it . this results in the pressure signature known as the n-wave . what does this shape mean ? well , the sonic boom occurs when there is a sudden change in pressure , and the n-wave involves two booms : one for the initial pressure rise at the aircraft 's nose , and another for when the tail passes , and the pressure suddenly returns to normal . this causes a double boom , but it is usually heard as a single boom by human ears . in practice , computer models using these principles can often predict the location and intensity of sonic booms for given atmospheric conditions and flight trajectories , and there is ongoing research to mitigate their effects . in the meantime , supersonic flight over land remains prohibited . so , are sonic booms a recent creation ? not exactly . while we try to find ways to silence them , a few other animals have been using sonic booms to their advantage . the gigantic diplodocus may have been capable of cracking its tail faster than sound , at over 1200 km/h , possibly to deter predators . some types of shrimp can also create a similar shock wave underwater , stunning or even killing pray at a distance with just a snap of their oversized claw . so while we humans have made great progress in our relentless pursuit of speed , it turns out that nature was there first .
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some tried to circumvent the problem through risky dives , often with tragic results . finally , in 1947 , design improvements , such as a movable horizontal stabilizer , the all-moving tail , allowed an american military pilot named chuck yeager to fly the bell x-1 aircraft at 1127 km/h , becoming the first person to break the sound barrier and travel faster than the speed of sound . the bell x-1 was the first of many supersonic aircraft to follow , with later designs reaching speeds over mach 3 .
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describe the dramatic change in the wavefronts before and after an aircraft breaks the sound barrier .
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hi , i 'm medium invader from the classic video game space invaders , and i want to tell you a little bit about where video games came from . a video game is an electronic game that has an interface designed for human interaction on a video device . simple . video games are used by scientists , the military , and people like you , and their evolution has spread across arcades , consoles , computers , smart phones , and all kinds of other electronics . these days video games are everywhere , but they were actually made in science labs . in fact , the earliest u.s. video game patent on record was in 1948 , and at the time it was referred to as a cathode-ray tube amusement device . that 's a mouthful ! some of the earliest video games include the nimrod computer , oxo , tennis for two , and my personal favorite , spacewar ! but none of these early video games were ever sold to the public because they were either too huge or too expensive to get out of the lab . this all changed when a man named ralph baer looked at his television screen and wondered how else it might be used . in 1972 , baer 's idea to get video games out of the science lab and into the living room led to the release of a game console called odyssey . odyssey allowed you to play a game on your tv . at about the same time , two other people , nolan bushnell and ted dabney , were working on something similar in a little company called atari . you might have heard of it , and even if you have n't , i 'm sure that your dad has . atari 's first major game release was in 1972 , an arcade game called pong . it was an immediate hit , and it 's credited as the first commercially successful video game . atari then released a home version of pong in 1974 . by 1978 , competition between atari and another game company called midway was heating up . midway had licensed an arcade game for the japanese company , taito , that put them on the map . the game : space invaders . it featured iconic actors , like me , and it went on to become the second highest selling arcade game of all time . space invaders also helped kick off what is known as the golden age of arcade games . in response , atari followed with the release of the arcade game asteroids , which ranked sixth on the list of highest selling arcade games . it was a good game , but it 's no space invaders . by 1980 , color came to arcade games , and this was also the year that another video gaming milestone was born . pac-man , created by the japanese company namco , was brought to the u.s. by midway . important to the spread of video games into popular culture , pac-man was a character that could be licensed . it was n't long before it had a song on the charts , a saturday morning television show , and all sorts of other products . in just a year , pac-man arcade games made over one billion dollars in quarters . then , in 1981 , a company called nintendo started making waves in the u.s. video game market with their release of donkey kong . it was the earliest video game to have a story line . the story went a bit like this : donkey kong is the pet of a carpenter named jumpman . jumpman mistreats his pet ape , so the ape steals his girlfriend , leaving the game player to assume the role of jumpman and rescue the girl . jumpman was eventually renamed to mario . other iconic arcade games from the early 80s include frogger , dragon 's lair , and mario brothers . perhaps the last iconic game considered to be part of the golden age of arcade games is double dragon . it was the first really successful example of the beat-them-up genre . it was released in 1987 , and , like donkey kong , it featured a damsel in distress storyline , a storyline common in many video games . by the mid-90s , the golden age of arcade games was coming to an end , and the home game console was gaining in popularity . while arcade games continued to decline in sales over the years , the popularity of video games was merely beginning , and we 'll talk about that and a lot more in part two of a brief history of video games .
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by the mid-90s , the golden age of arcade games was coming to an end , and the home game console was gaining in popularity . while arcade games continued to decline in sales over the years , the popularity of video games was merely beginning , and we 'll talk about that and a lot more in part two of a brief history of video games .
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what kind of a person was most likely to develop an interest in video games in the 50s , 60s and 70s ? why ?
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hunger claws at your grumbling belly . it tugs at your intestines , which begin to writhe , aching to be fed . being hungry generates a powerful , often unpleasant physical sensation that 's almost impossible to ignore . after you 've reacted by gorging on your morning pancakes , you start to experience an opposing force , fullness , but how does your body actually know when you 're full ? the sensation of fullness is set in motion as food moves from your mouth down your esophagus . once it hits your stomach , it gradually fills the space . that causes the surrounding muscular wall to stretch , expanding slowly like a balloon . a multitude of nerves wrapped intricately around the stomach wall sense the stretching . they communicate with the vagus nerve up to the brainstem and hypothalamus , the main parts of the brain that control food intake . but that 's just one input your brain uses to sense fullness . after all , if you fill your stomach with water , you wo n't feel full for long . your brain also takes into account chemical messengers in the form of hormones produced by endocrine cells throughout your digestive system . these respond to the presence of specific nutrients in your gut and bloodstream , which gradually increase as you digest your food . as the hormones seep out , they 're swept up by the blood and eventually reach the hypothalamus in the brain . over 20 gastrointestinal hormones are involved in moderating our appetites . one example is cholecystokinin , which is produced in response to food by cells in the upper small bowel . when it reached the hypothalamus , it causes a reduction in the feeling of reward you get when you eat food . when that occurs , the sense of being satiated starts to sink in and you stop eating . cholecystokinin also slows down the movement of food from the stomach into the intestines . that makes your stomach stretch more over a period of time , allowing your body to register that you 're filling up . this seems to be why when you eat slowly , you actually feel fuller compared to when you consume your food at lightning speed . when you eat quickly , your body does n't have time to recognize the state it 's in . once nutrients and gastrointestinal hormones are present in the blood , they trigger the pancreas to release insulin . insulin stimulates the body 's fat cells to make another hormone called leptin . leptin reacts with receptors on neuron populations in the hypothalamus . the hypothalamus has two sets of neurons important for our feeling of hunger . one set produces the sensation of hunger by making and releasing certain proteins . the other set inhibits hunger through its own set of compounds . leptin inhibits the hypothalamus neurons that drive food intake and stimulates the neurons that suppress it . by this point , your body has reached peak fullness . through the constant exchange of information between hormones , the vagus nerve , the brainstem , and the different portions of hypothalamus , your brain gets the signal that you 've eaten enough . researchers have discovered that some foods produce more long-lasting fullness than others . for instance , boiled potatoes are ranked as some of the most hunger-satisfying foods , while croissants are particularly unsatisfying . in general , foods with more protein , fiber , and water tend to keep hunger at bay for longer . but feeling full wo n't last forever . after a few hours , your gut and brain begin their conversation again . your empty stomach produces other hormones , such as ghrelin , that increase the activity of the hunger-causing nerve cells in the hypothalamus . eventually , the growling beast of hunger is reawakened . luckily , there 's a dependable antidote for that .
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after all , if you fill your stomach with water , you wo n't feel full for long . your brain also takes into account chemical messengers in the form of hormones produced by endocrine cells throughout your digestive system . these respond to the presence of specific nutrients in your gut and bloodstream , which gradually increase as you digest your food .
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what can act as a signal for the release of satiety hormones from endocrine cells ?
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homer 's `` odyssey '' , one of the oldest works of western literature , recounts the adventures of the greek hero odysseus during his ten-year journey home from the trojan war . though some parts may be based on real events , the encounters with strange monsters , terrifying giants and powerful magicians are considered to be complete fiction . but might there be more to these myths than meets the eye ? let 's look at one famous episode from the poem . in the midst of their long voyage , odysseus and his crew find themselves on the mysterious island of aeaea . starving and exhausted , some of the men stumble upon a palatial home where a stunning woman welcomes them inside for a sumptuous feast . of course , this all turns out to be too good to be true . the woman , in fact , is the nefarious sorceress circe , and as soon as the soldiers have eaten their fill at her table , she turns them all into animals with a wave of her wand . fortunately , one of the men escapes , finds odysseus and tells him of the crew 's plight . but as odysseus rushes to save his men , he meets the messenger god , hermes , who advises him to first consume a magical herb . odysseus follows this advice , and when he finally encounters circe , her spells have no effect on him , allowing him to defeat her and rescue his crew . naturally , this story of witchcraft and animal transformations was dismissed as nothing more than imagination for centuries . but in recent years , the many mentions of herbs and drugs throughout the passage have piqued the interest of scientists , leading some to suggest the myths might have been fictional expressions of real experiences . the earliest versions of homer 's text say that circe mixed baneful drugs into the food such that the crew might utterly forget their native land . as it happens , one of the plants growing in the mediterranean region is an innocent sounding herb known as jimson weed , whose effects include pronounced amnesia . the plant is also loaded with compounds that disrupt the vital neurotransmitter called acetylcholine . such disruption can cause vivid hallucinations , bizarre behaviors , and general difficulty distinguishing fantasy from reality , just the sorts of things which might make people believe they 've been turned into animals , which also suggests that circe was no sorceress , but in fact a chemist who knew how to use local plants to great effect . but jimson weed is only half the story . unlike a lot of material in the odyssey , the text about the herb that hermes gives to odysseus is unusually specific . called moly by the gods , it 's described as being found in a forest glen , black at the root and with a flower as white as milk . like the rest of the circe episode , moly was dismissed as fictional invention for centuries . but in 1951 , russian pharmacologist mikhail mashkovsky discovered that villagers in the ural mountains used a plant with a milk-white flower and a black root to stave off paralysis in children suffering from polio . the plant , called snowdrop , turned out to contain a compound called galantamine that prevented the disruption of the neurotransmitter acetylcholine , making it effective in treating not only polio but other disease , such as alzheimer 's . at the 12th world congress of neurology , doctors andreas plaitakis and roger duvoisin first proposed that snowdrop was , in fact , the plant hermes gave to odysseus . although there is not much direct evidence that people in homer 's day would have known about its anti-hallucinatory effects , we do have a passage from 4th century greek writer theophrastus stating that moly is used as an antidote against poisons . so , does this all mean that odysseus , circe , and other characters in the odyssey were real ? not necessarily . but it does suggest that ancient stories may have more elements of truth to them than we previously thought . and as we learn more about the world around us , we may uncover some of the same knowledge hidden within the myths and legends of ages passed .
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let 's look at one famous episode from the poem . in the midst of their long voyage , odysseus and his crew find themselves on the mysterious island of aeaea . starving and exhausted , some of the men stumble upon a palatial home where a stunning woman welcomes them inside for a sumptuous feast .
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is the tale of odysseus ’ s visit to aeaea mythology or history ? why do think so ? what is the difference between mythology and history ?
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after witnessing the violent rage shown by babies whenever deprived of an item they considered their own , jean piaget , a founding father of child psychology , observed something profound about human nature . our sense of ownership emerges incredibly early . why are we so clingy ? there 's a well-established phenomenon in psychology known as the endowment effect where we value items much more highly just as soon as we own them . in one famous demonstration , students were given a choice between a coffee mug or a swiss chocolate bar as a reward for helping out with research . half chose the mug , and half chose the chocolate . that is , they seemed to value the two rewards similarly . other students were given a mug first and then a surprise chance to swap it for a chocolate bar , but only 11 % wanted to . yet another group started out with chocolate , and most preferred to keep it rather than swap . in other words , the students nearly always put greater value on whichever reward they started out with . part of this has to do with how quickly we form connections between our sense of self and the things we consider ours . that can even be seen at the neural level . in one experiment , neuroscientists scanned participants ' brains while they allocated various objects either to a basket labeled `` mine , '' or another labeled , `` alex 's . '' when participants subsequently looked at their new things , their brains showed more activity in a region that usually flickers into life whenever we think about ourselves . another reason we 're so fond of our possessions is that from a young age we believe they have a unique essence . psychologists showed us this by using an illusion to convince three to six-year-olds they built a copying machine , a device that could create perfect replicas of any item . when offered a choice between their favorite toy or an apparently exact copy , the majority of the children favored the original . in fact , they were often horrified at the prospect of taking home a copy . this magical thinking about objects is n't something we grow out of . rather it persists into adulthood while becoming ever more elaborate . for example , consider the huge value placed on items that have been owned by celebrities . it 's as if the buyers believed the objects they 'd purchased were somehow imbued with the essence of their former celebrity owners . for similar reasons , many of us are reluctant to part with family heirlooms which help us feel connected to lost loved ones . these beliefs can even alter our perception of the physical world and change our athletic abilities . participants in a recent study were told they were using a golf putter once owned by the champion ben curtis . during the experiment , they perceived the hole as being about a centimeter larger than controlled participants using a standard putter and they sank slightly more putts . although feelings of ownership emerge early in life , culture also plays a part . for example , it was recently discovered that hadza people of northern tanzania who are isolated from modern culture do n't exhibit the endowment effect . that 's possibly because they live in an egalitarian society where almost everything is shared . at the other extreme , sometimes our attachment to our things can go too far . part of the cause of hoarding disorder is an exaggerated sense of responsibility and protectiveness toward one 's belongings . that 's why people with this condition find it so difficult to throw anything away . what remains to be seen today is how the nature of our relationship with our possessions will change with the rise of digital technologies . many have forecast the demise of physical books and music , but for now , at least , this seems premature . perhaps there will always be something uniquely satisfying about holding an object in our hands and calling it our own .
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although feelings of ownership emerge early in life , culture also plays a part . for example , it was recently discovered that hadza people of northern tanzania who are isolated from modern culture do n't exhibit the endowment effect . that 's possibly because they live in an egalitarian society where almost everything is shared .
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the fact that the hadza people of northern tanzania don ’ t show the endowment effect is important because :
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many modern musical instruments are cumbersome or have a lot of parts . some need a stand or a stool . but the cajon is a drum , a stand and a seat all in one convenient box . and this simplicity may be key to its journey across continents and cultures to become one of the most popular percussion instruments in the world today . the cajon 's story begins in west africa , whose indigenousness people had rich musical traditions centered on drumming and dancing . when many of them were captured and brought to the americas as slaves , they brought this culture with them , but without their native instruments , they had to improvise . african slaves in coastal peru did n't have the materials or the opportunity to craft one of their traditional drums such as a djembe or a djun djun . but what they did have were plenty of shipping crates . not only were these readily accessible , but their inconspicuous appearance may have helped get around laws prohibiting slaves from playing music . early peruvian cajons consisted of a simple box with five thick wooden sides . the sixth side , made of a thinner sheet of wood , would be used as the striking surface , or more commonly known as the tapa . a sound hole was also cut into the back to allow the sound to escape . as an afro-peruvian culture developed , and new forms of music and dance , such as zamacueca , festejo and landó were born , the cajon became a dedicated musical instrument in its own right . early modifications involved simply bending the planks of the box to tweak the sound , and when abolition of slavery introduced the cajon to a broader population , more improvisation and experimentation soon followed . perhaps the person most responsible for introducing the cajon to european audiences was spanish flamenco guitarist paco de lucía . when touring in peru in 1977 , he and his percussionist rubem dantas discovered the cajon and brought it back to spain , recognizing its potential for use in flamenco music . by stretching guitar strings along the inside of the tapa , the flamenco musicians were able to create a buzz-like snare sound . combined with the regular base tone , this gave the cajon a sound close to a basic drum set . the cajon quickly caught on , not only becoming standard in flamenco , but being used in genres like folk , jazz , blues and rock . today , many specialized cajons are manufactured , some with adjustable strings , some with multiple playing surfaces , and some with a snare mechansim . but the basic concept remains the same , and the story of the cajon shows that the simplest things can have the most amazing potential when you think outside and inside the box .
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and this simplicity may be key to its journey across continents and cultures to become one of the most popular percussion instruments in the world today . the cajon 's story begins in west africa , whose indigenousness people had rich musical traditions centered on drumming and dancing . when many of them were captured and brought to the americas as slaves , they brought this culture with them , but without their native instruments , they had to improvise .
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what were some obstacles the west african slaves might have had to overcome in order to keep their drumming and dancing traditions alive ?
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when you think about the brain , it 's difficult to understand , because if i were to ask you right now , how does the heart work , you would instantly tell me it 's a pump . it pumps blood . if i were to ask about your lungs , you would say it exchanges oxygen for carbon dioxide . that 's easy . if i were to ask you how the brain works , it 's hard to understand because you ca n't just look at a brain and understand what it is . it 's not a mechanical object , not a pump , not an airbag . it 's just like , if you held it in your hand when it was dead , it 's just a piece of fat . to understand how the brain works , you have to go inside a living brain . because the brain 's not mechanical , the brain is electrical and it 's chemical . your brain is made out of 100 billion cells , called neurons . and these neurons communicate with each other with electricity . and we 're going to eavesdrop in on a conversation between two cells , and we 're going to listen to something called a spike . but we 're not going to record my brain or your brain or your teachers ' brains , we 're going to use our good friend the cockroach . not just because i think they 're cool , but because they have brains very similar to ours . so if you learn a little bit about how their brains work , we 're going to learn a lot about how our brains work . i 'm going to put them in some ice water here and then -- audience : ew ! greg gabe : yeah ... right now they 're becoming anesthetized . because they 're cold blooded , they become the temperature of the water and they ca n't control it so they just basically `` chillax , '' right ? they 're not going to feel anything , which may tell you a little about what we 're going to do , a scientific experiment to understand the brain . so ... this is the leg of a cockroach . and a cockroach has all these beautiful hairs and pricklies all over it . underneath each one of those is a cell , and this cell 's a neuron that is going to send information about wind or vibration . if you ever try to catch a cockroach , it 's hard because they can feel you coming before you 're even there , they start running . these cells are zipping up this information up to the brain using those little axons with electronic messages in there . we 're going to record by sticking a pin right in there . we need to take off the leg of a cockroach -- do n't worry , they 'll grow back -- then we 're going to put two pins in there . these are metal pins . one will pick up this electronic message , this electric message is going by . so , we 're now going to do the surgery , let 's see if you guys can see this . yeah , it 's gross ... all right . so there we go . you guys can see his leg right there . now i 'm going to take this leg , i 'm going to put it in this invention that we came up with called the spikerbox -- and this replaces lots of expensive equipment in a research lab , so you guys can do this in your own high schools , or in your own basements if it 's me . ( audience : laughter ) so , there . can you guys see that ? alright , so i 'm going to go ahead and turn this on . i 'm going to plug it in . ( tuning sound ) to me , this is the most beautiful sound in the world . this is what your brain is doing right now . you have 100 billion cells making these raindrop-type noises . let 's take a look at what it looks like , let 's pull it up on the ipad screen . i plugged my ipad into here as well . so remember we said the axon looks like a spike . so we 're going to take a look at what one of them looks like in just a brief second . we 're going to tap here , so we can sort of average this guy . so there we see it . that 's an action potential . you 've got 100 billion cells in your brain doing this right now , sending all this information back about what you 're seeing , hearing . we also said this is a cell that 's going to be taking up information about vibrations in the wind . so what if we do an experiment ? we can actually blow on this and hear if we see a change . are you guys going to be ready ? if i blow on it you tell me if you hear anything . ( blowing ) ( sound changes ) let me just touch this with a little pen here . ( noise ) that was the neural firing rate . that actually took a while in neuroscience to understand this . this is called rate coding : the harder you press on something , the more spikes there are , and all that information is coming up to your brain . that 's how you perceive things . so that 's one way of doing an experiment with electricity . the other way is that your brain is not only taking in electrical impulses , you 're also sending out . that 's how you move your muscles around . let 's see what happens if i 've plugged in something that 's electric into the cockroach leg here . i 'm going to take two pins , i 'm going to plug them onto the cockroach . i 'm going to take the other end , i 'm going to plug in into my ipod . it 's my iphone actually . do you guys know how your earbuds work in your ears ? you have a battery in your phone , or ipod , right ? it 's sending electrical current into these magnets in your earbuds which shake back and forth and allow you to hear things . but that current 's the same currency that our brain uses , so we can send that to our cockroach leg and hopefully if this works , we can actually see what happens when we play music into the cockroach . let 's take a look . ( music beat ) can we turn it up ? there we go . ( audience reacts and gasps ) gg : so what 's happening ? audience : wow ! ( laughter ) so you see what 's moving . it 's moving on the bass . all those audiophiles out there , if you have awesome , kicking car stereos , you know , the bass speakers are the biggest speakers . the biggest speakers have the longest waves , which have the most current , and the current is what 's causing these things to move . so it 's not just speakers that are causing electricity . microphones also cause electricity . ( beat ) so i 'm going to go ahead and invite another person out on the stage here to help me out with this . so there we go . ( beatboxing ) this is the first time this has ever happened in the history of mankind . human beatbox to a cockroach leg . when you guys go back to your high school , think about neuroscience and how you guys can begin the neuro-revolution . thank you very much . bye bye . ( applause )
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so there we see it . that 's an action potential . you 've got 100 billion cells in your brain doing this right now , sending all this information back about what you 're seeing , hearing .
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action potentials or “ spikes ” are used by the nervous system to send :
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translator : andrea mcdonough reviewer : bedirhan cinar there has never been a time to make things as good as right now . between what 's available on the internet , like the stuff on youtube , the stuff on instructables , make magazine , between the quality of your teachers who know so much and the incredible availability of parts , and tools , and supplies , there 's almost nothing that you ca n't make , almost nothing you ca n't make , if you really try . now in my career , i 've made a lot of stuff . i 've made telescopes , i 've made microscopes , i know people who made electron microscopes . i personally made flamethrowers . i made a four-story high trebuchet . um , i 've made some really dangerous stuff . my favorite is i made a battlebot when battlebots were kind of big . you know , it was metal , it had 20 horsepower motors , it had a carbon-tip fireman cut-off saw in the front . that thing could , you know , eat its way out of a steel room . i 've made just so many things . but not everything you have to make is dangerous to be cool . the point is , is that it 's just fun to make stuff and if you 've got a really good idea , you could probably do it . now , there are different styles of making things . there 's do it yourself and that 's like , `` well , i 'm going to fix the brakes on my car or put siding on my house , '' and that 's an interesting kind of diy . but there 's hacking , where you take one item that 's purposed for something else and turn it into something , you know , cooler , something different . there 's bricolage , which means making things from found objects . there 's kitting , which means you buy a kit , something complicated , probably , and put it together . and there 's inventing , and inventing is the best ! the best kind of making things involves not just following directions from people who have done things before , but actually going out there , figuring out how to make something , doing the design yourself , and then actually building it . now , i do n't have a lot of time , but i want to get you started on your own invention project , maybe . so what i 'm going to do live and real-time and something that scares me , is , because it is live and real-time , is i 'm going to make an audio speaker out of stuff that i found in my kitchen on the night before i came to new york . okay . so what i 've got here is a block of wood . i 've got some sand paper . i 've got some pieces of notebook paper folded up into a rough `` z '' shape . i 've got two magnets . and , i 've got some wire . now , this wire is the key part . the four things that i need to make my own speaker is a diaphragm , a coil , a support , and a magnet . so first thing 's first . let 's start doing it . what i need to do is wind a coil . and what i 'm going to do is take this wire and wind an entire voice coil from it . now , unfortunately that 's going to take a really long time , and i do n't have much time , so i 'm just going to give you the flavor of it . i 'm going to take 30 gauge magnet wire and i 'm just going to wrap it tightly together , and i 'm going to do about 150 turns on a 3/4 inch wooden dowel . now why would i do that ? because i want to get my coil to have about 4 ohms of resistance . if you do n't have enough resistance , you can do something bad to your amplifier . and then once that 's done , i 'm going to glue it all together so it 's nice and tight . now i do n't nearly have 150 coils there so i made one in advance and i 'm going to use that one . so where is it ? here it is . what i 'm going to do is simply hot glue it to the back of this yogurt cup . and i had to eat a lot of yogurt while i was experimenting , so i feel like i 've got all the calcium i need for a while . now , the next thing i 'm going to do is take these magnets and glue it in the center of this dot . hot glue , by the way , a hot glue gun , it 's the greatest maker toy you can possibly have . i do n't care what the 3-d prototype guys say , i love my hot glue gun ! what i 'm going to do next is take these little `` z '' stand-offs , see ? and i 'm going to put some glue there . look how fast that bonds ! my god , this is great stuff ! and i 'm going to do that , and then i 'm going to glue this . and i 'm going to center that coil right over those magnets so it 's just above it . and now it 's done . now this needs to dry . so you know how martha stewart would take the cake out of the oven , it 's pre-made ? we 're going to do that , we 're going to go to the martha stewart one . so this is the one i made earlier today . and it 's the yogurt cup , the stand-offs , and everything else . well , i 'm going to turn on my ipod . we 'll see if we get some music . i need a microphone . hello ? it 's on , good deal . so , let 's play something . [ music plays . ] now this is really coming from a yogurt cup and it 's kind of a neat deal . might not be your choice of music . now you can experiment with different things . in fact , i did . last night i did this . let me walk over here . i made all these different speakers out of different things . here 's one . because i 'm in new york , i made one out of a piece of matzo . i made one out of a coffee cup lid . i made one out of a tostito . the tostito looks like a speaker , does n't it ? so , you can imagine how good that works . and then last night during rehearsals they gave us some food , and they gave us these thick potato chips . you 've got to hear this , you guys . this is just incredible how nice that sounds . [ music plays . ] it 's just incredible . so anyway , like i said , today is the very best time , this age is the very best time to be a maker . you can make so many things if you put your mind to it . get out there , pick something up because , i 'll tell you , the stuff you make , the stuff you make is way better than the stuff you buy . it 's special , it 's significant to you , and i really encourage you to do that . thanks a lot for listening to me .
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now , the next thing i 'm going to do is take these magnets and glue it in the center of this dot . hot glue , by the way , a hot glue gun , it 's the greatest maker toy you can possibly have . i do n't care what the 3-d prototype guys say , i love my hot glue gun !
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according to gurstelle , what is the greatest maker toy you can possibly own ?
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translator : tom carter reviewer : bedirhan cinar literary critic northrop frye once observed that in our primitive days , our literary heroes were -- well , nearly gods , and as civilization advanced , they came down the mountain of the gods , so to speak , and became more human , more flawed , less heroic . from the divine heroes like hercules , down the mountain below the miraculous but mortal heroes such as beowulf , the great leaders such as king arthur , and the great but flawed heroes like macbeth or othello . below even the unlikely but eventual heroes such as harry potter , luke skywalker , or hiccup , until we reach the bottom and meet the anti-hero . contrary to the sound , the anti-hero is not the villain , not the antagonist . the anti-hero is actually the main character in some contemporary works of literature . guy montag in `` fahrenheit 451 , '' winston smith in `` 1984 , '' who unwittingly ends up challenging those in power -- that is , those who abuse their power to brainwash the populace to believe that the ills of society have been eliminated . ideally , those who challenge the establishment should be wise , confident , brave , physically strong , with a type of charisma that inpires followers . the anti-hero , however , at best demonstrates a few underdeveloped traits , at worst , is totally inept . the story of the anti-hero usually unfolds something like this . the anti-hero initially conforms , ignorantly accepting the established views , a typical , unquestioning , brainwashed member of society . the anti-hero struggles to conform , all the while starting to object , perhaps finding other outsiders with whom to voice his questions , and naïvely , unwisely , sharing those questions with an authority figure . the anti-hero openly challenges society , and tries to fight against the lies and tactics used to oppress the populace . this step , for the anti-hero , is seldom a matter of brave , wise and heroic opposition . maybe the anti-hero fights and succeeds in destroying the oppressive government , with a lot of impossible luck . perhaps he or she runs away , escapes to fight another day . all too often though , the anti-hero is killed , or brainwashed to return to conformity with the masses . no heroic triumph here , no brave individual standing up against impersonal institutions of a modern world , inspiring others to fight , or resourcefully outwitting and outgunning the massive army of the evil empire . our storytelling ancestors calmed our fears of powerlessness by giving us hercules and other heroes strong enough to fight off the demons and monsters that we suspected haunted the night beyond our campfires . but eventually , we realized the monsters did not lie out there , they reside inside of us . beowulf 's greatest enemy was mortality . othello 's , jealousy . hiccup , self-doubt . and in the tales of the ineffectual anti-hero , in the stories of guy montag and winston smith , lie the warnings of contemporary storytellers playing on very primitive fears : that we are not strong enough to defeat the monsters . only this time , not the monsters chased away by the campfire , but the very monsters who built the campfire in the first place .
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the anti-hero , however , at best demonstrates a few underdeveloped traits , at worst , is totally inept . the story of the anti-hero usually unfolds something like this . the anti-hero initially conforms , ignorantly accepting the established views , a typical , unquestioning , brainwashed member of society .
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which does the antihero usually do ?
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modern computers are revolutionizing our lives , performing tasks unimaginable only decades ago . this was made possible by a long series of innovations , but there 's one foundational invention that almost everything else relies upon : the transistor . so what is that , and how does such a device enable all the amazing things computers can do ? well , at their core , all computers are just what the name implies , machines that perform mathematical operations . the earliest computers were manual counting devices , like the abacus , while later ones used mechanical parts . what made them computers was having a way to represent numbers and a system for manipulating them . electronic computers work the same way , but instead of physical arrangements , the numbers are represented by electric voltages . most such computers use a type of math called boolean logic that has only two possible values , the logical conditions true and false , denoted by binary digits one and zero . they are represented by high and low voltages . equations are implemented via logic gate circuits that produce an output of one or zero based on whether the inputs satisfy a certain logical statement . these circuits perform three fundamental logical operations , conjunction , disjunction , and negation . the way conjunction works is an `` and gate '' provides a high-voltage output only if it receives two high-voltage inputs , and the other gates work by similar principles . circuits can be combined to perform complex operations , like addition and subtraction . and computer programs consist of instructions for electronically performing these operations . this kind of system needs a reliable and accurate method for controlling electric current . early electronic computers , like the eniac , used a device called the vacuum tube . its early form , the diode , consisted of two electrodes in an evacuated glass container . applying a voltage to the cathode makes it heat up and release electrons . if the anode is at a slightly higher positive potential , the electrons are attracted to it , completing the circuit . this unidirectional current flow could be controlled by varying the voltage to the cathode , which makes it release more or less electrons . the next stage was the triode , which uses a third electrode called the grid . this is a wire screen between the cathode and anode through which electrons could pass . varying its voltage makes it either repel or attract the electrons emitted by the cathode , thus , enabling fast current-switching . the ability to amplify signals also made the triode crucial for radio and long distance communication . but despite these advancements , vacuum tubes were unreliable and bulky . with 18,000 triodes , eniac was nearly the size of a tennis court and weighed 30 tons . tubes failed every other day , and in one hour , it consumed the amount of electricity used by 15 homes in a day . the solution was the transistor . instead of electrodes , it uses a semiconductor , like silicon treated with different elements to create an electron-emitting n-type , and an electron absorbing p-type . these are arranged in three alternating layers with a terminal at each . the emitter , the base , and the collector . in this typical npn transistor , due to certain phenomena at the p-n interface , a special region called a p-n junction forms between the emitter and base . it only conducts electricity when a voltage exceeding a certain threshold is applied . otherwise , it remains switched off . in this way , small variations in the input voltage can be used to quickly switch between high and low-output currents . the advantage of the transistor lies in its efficiency and compactness . because they do n't require heating , they 're more durable and use less power . eniac 's functionality can now be surpassed by a single fingernail-sized microchip containing billions of transistors . at trillions of calculations per second , today 's computers may seem like they 're performing miracles , but underneath it all , each individual operation is still as simple as the flick of a switch .
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if the anode is at a slightly higher positive potential , the electrons are attracted to it , completing the circuit . this unidirectional current flow could be controlled by varying the voltage to the cathode , which makes it release more or less electrons . the next stage was the triode , which uses a third electrode called the grid .
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how is a triode made ? how could it control the flow of current through it ?
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translator : andrea mcdonough reviewer : jessica ruby the next time you see a news report of a hurricane or a tropical storm showing high winds battering trees and houses , ask yourself , `` how did the wind get going so fast ? '' amazingly enough , this is a motion that started more than five billion years ago . but , to understand why , we need to understand spin . in physics , we talk about two types of motion . the first is straight-line motion . you push on something , and it moves forward . the second type , spin , involves an object rotating , or turning on its axis in place . an object in straight-line motion will move forever unless something , like the friction of the ground beneath it , causes it to slow down and stop . the same thing happens when you get something spinning . it will keep on spinning until something stops it . but the spin can speed up . if an ice skater is gliding across the ice in straight-line motion and she pulls her arms in , she keeps on gliding at the same speed . but if she is spinning on the ice and she pulls her arms in , you know what happens next . she spins faster . this is called the conservation of angular momentum . mathematically , angular momentum is a product of two numbers , one that gives the spin rate and one that gives the distance of the mass from the axis . if something is freely spinning , as one number gets bigger , the other gets smaller . arms closer , spin faster . arms farther , spin slower . spin causes other effects , too . if you are riding on a spinning merry-go-round and you toss a ball to a friend , it will appear to follow a curving path . it does n't actually curve , though . it really goes in a straight line . you were the one who was following a curving path , but , from your point of view , the ball appears to curve . we call this the coriolis effect . oh , and you are riding on a speeding merry-go-round right now at this very moment . we call it the earth . the earth spins on its axis once each day . but why does the earth spin ? now , that 's a story that starts billions of years ago . a cloud of dust and gas that form the sun and the earth and the planets and you and me started to collapse as gravity pulled it all together . before it started to collapse , this cloud had a very gentle spin . and , as it collapsed , like that ice skater pulling her arms in , the spin got faster and faster . and everything that formed out of the cloud , the sun and the planets around the sun and the moons around the planets , all inherited this spin . and this inherited spin is what gives us night and day . and this day-night cycle is what drives our weather . the earth is warm on the daytime side , cool on the nighttime side , and it 's warmer at the equator than at the poles . the differences in temperature make differences in air pressure , and the differences in air pressure make air move . they make the wind blow . but , because the earth spins , the moving air curves to the right in the northern hemisphere because of the coriolis effect . if there 's a region of low pressure in the atmosphere , air is pushed toward it , like water going down a drain . but the air curves to the right as it goes , and this gives it a spin . with the dramatic low pressure in a storm , the air gets pulled in tighter and tighter , so it gets going faster and faster , and this is how we get the high winds of a hurricane . so , when you see a spinning storm on a weather report , think about this : the spin ultimately came from the spin of the earth , and the earth 's spin is a remnant , a fossil relic , of the gentle spin of the cloud of dust and gas that collapsed to make the earth some five billion years ago . you are watching something , the spin , that is older than dirt , that 's older than rocks , that 's older than the earth itself .
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oh , and you are riding on a speeding merry-go-round right now at this very moment . we call it the earth . the earth spins on its axis once each day . but why does the earth spin ?
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the angular momentum of the earth plus that of the moon is conserved . as time goes on , the earth spins less rapidly . thinking by analogy with the case of the ice skater , this means that the moon must :
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translator : andrea mcdonough reviewer : bedirhan cinar miss gayle 's 5 steps to slam poetry , a lesson of transformation . step 1 : write it all down . `` take one memory , explore it like a new land , '' the visiting poet tells the class . `` do n't leave anything out . '' tyler sits in this high school workshop , dizzy with where to start . memories wander in and out of his heart like vagrants searching for home . he bends to his desk , he writes , `` the snow goes black when the moon turns its eyes away , all paper is yellow , all letters spell eviction note , mama 's lies are footsteps too many to count . making excuses on black snow . 'i paid the rent , this is your room forever , baby . i love you . ' but , she would n't even look at me . '' step 2 : read out loud . as he writes , his lips try on words then toss them out like bad tenants . he pushes his desk back , stands . `` aunt jocelyn 's rice pudding was sweet , but that 's not what i want to write . have you ever been so cold your hair becomes an icicle ? your little sister 's fear of the dark freezes on her lips like she 's kissed the ice tray ? how hungry have you been ? '' step 3 : cut the fat . abandon extra words . his pen becomes a machete , slashing ands , thens , becauses . step 4 : read out loud , again . the 11th grade boy makes sure step 3 's cuts were n't too deep . step 5 : add flava . juice , power , movement , emotion . `` vanilla flavoring is the secret to my aunt 's pudding . i kick out a few raisins but leave one or two . life needs some bitter to man up the sweet . '' his hands reach out like shells to hold our disbelief . is this tyler speaking ? the one who keeps his eyes on the floor like they 're carrying something heavy ? voice rattles windows . `` i am free now . '' body quivers with the pulse of each word . `` the sun 's joy melts snow . '' fingers trace the curve of his jaw . `` my aunt 's face was warm as a water heater when she let us in that night . '' our boy is done , his transformation complete . step 1 : write it all down . step 2 : read out loud . step 3 : cut the fat . step 4 : read out loud . step 5 : add flava . tyler 's first poem takes residence in his heart . he flings his arms wide like an open door . welcome home !
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how hungry have you been ? '' step 3 : cut the fat . abandon extra words .
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when ms. gayle says , `` cut the fat , '' she means :
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we read fiction for many reasons . to be entertained , to find out who done it , to travel to strange , new planets , to be scared , to laugh , to cry , to think , to feel , to be so absorbed that for a while we forget where we are . so , how about writing fiction ? how do you suck your readers into your stories ? with an exciting plot ? maybe . fascinating characters ? probably . beautiful language ? perhaps . `` billie 's legs are noodles . the ends of her hair are poison needles . her tongue is a bristly sponge , and her eyes are bags of bleach . '' did that description almost make you feel as queasy as billie ? we grasp that billie 's legs are n't actually noodles . to billie , they feel as limp as cooked noodles . it 's an implied comparison , a metaphor . so , why not simply write it like this ? `` billie feels nauseated and weak . '' chances are the second description was n't as vivid to you as the first . the point of fiction is to cast a spell , a momentary illusion that you are living in the world of the story . fiction engages the senses , helps us create vivid mental simulacra of the experiences the characters are having . stage and screen engage some of our senses directly . we see and hear the interactions of the characters and the setting . but with prose fiction , all you have is static symbols on a contrasting background . if you describe the story in matter of fact , non-tactile language , the spell risks being a weak one . your reader may not get much beyond interpreting the squiggles . she will understand what billie feels like , but she wo n't feel what billie feels . she 'll be reading , not immersed in the world of the story , discovering the truths of billie 's life at the same time that billie herself does . fiction plays with our senses : taste , smell , touch , hearing , sight , and the sense of motion . it also plays with our ability to abstract and make complex associations . look at the following sentence . `` the world was ghost-quiet , except for the crack of sails and the burbling of water against hull . '' the words , `` quiet , '' `` crack , '' and `` burbling , '' engage the sense of hearing . notice that buckell does n't use the generic word sound . each word he chooses evokes a particular quality of sound . then , like an artist laying on washes of color to give the sense of texture to a painting , he adds anoter layer , motion , `` the crack of sails , '' and touch , `` the burbling of water against hull . '' finally , he gives us an abstract connection by linking the word quiet with the word ghost . not `` quiet as a ghost , '' which would put a distancing layer of simile between the reader and the experience . instead , buckell creates the metaphor `` ghost-quiet '' for an implied , rather than overt , comparison . writers are always told to avoid cliches because there 's very little engagement for the reader in an overused image , such as `` red as a rose . '' but give them , `` love ... began on a beach . it began that day when jacob saw anette in her stewed-cherry dress , '' and their brains engage in the absorbing task of figuring out what a stewed-cherry dress is like . suddenly , they 're on a beach about to fall in love . they 're experiencing the story at both a visceral and a conceptual level , meeting the writer halfway in the imaginative play of creating a dynamic world of the senses . so when you write , use well-chosen words to engage sound , sight , taste , touch , smell , and movement . then create unexpected connotations among your story elements , and set your readers ' brushfire imaginations alight .
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we read fiction for many reasons . to be entertained , to find out who done it , to travel to strange , new planets , to be scared , to laugh , to cry , to think , to feel , to be so absorbed that for a while we forget where we are .
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which of these represents a cliché ?
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translator : andrea mcdonough reviewer : jessica ruby how do you get from point a to point b ? why not spice it up with homemade special effects ? a film is simply a series of images played in sequence to create the illusion of motion . if you manipulate those images , crazy things can happen . we used a tablet and one of the many stop motion apps out there . how do you get from point a to point b ? we started off by taking a bunch of pictures of celeste in place . then , just like stop motion animation , the character is moved just a bit before the next picture is taken , which , in this case , creates a sliding effect . here we use the oldest trick in the book . by alternating between photos of celeste on-screen and off-screen , we 've made her childhood dream of teleportation a reality . with a little creativity , there are a million ways you can used homemade special effects to make something as simple as getting from point a to point b much more fun . if you 're at a loss for ideas , try finding inspiration in your surroundings , like the refrigerator and your coat rack . you can even try incorporating everyday objects from around your house , like , say , umbrellas or binder clips . wherever there is an object , there is an opportunity to make it come to life . when humans are used in stop motion animation , that 's called pixilation , a term coined in the mid-twentieth century , well before the word pixel was a part of our vocabulary . but these sorts of special effects are as old as the art of film making , and thanks to today 's technologies , can be reproduced in your very own kitchen . moving an object from point a to point b is a fundamental principle of animation . to learn more about the process and the tools we used , visit the `` dig deeper '' section on ed.ted.com .
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wherever there is an object , there is an opportunity to make it come to life . when humans are used in stop motion animation , that 's called pixilation , a term coined in the mid-twentieth century , well before the word pixel was a part of our vocabulary . but these sorts of special effects are as old as the art of film making , and thanks to today 's technologies , can be reproduced in your very own kitchen . moving an object from point a to point b is a fundamental principle of animation . to learn more about the process and the tools we used , visit the `` dig deeper '' section on ed.ted.com .
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does knowing how animation works remove some of the magic , or does it open the possibilities ? are you interested in animating your own film ?
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the epic poem `` la dragontea '' describes how english explorer sir francis drake sailed across the gulf of venezuela in 1595 . he was aiming for the nearby lake maracaibo , home to a colony of spanish settlers he planned to overthrow . but as drake moved towards the mouth of the lake under cover of darkness , his plot was suddenly and magnificently foiled . huge flashes of lightning illuminated the landscape , exposing the fleet as if it were daytime , which warned the spanish about his approach . lake maracaibo is the stormiest place on the planet . the massive body of water at over 13,000 square kilometers is a place of almost perpetual storming . thunderstorms rage above it for up to 200 days of the year , each earsplitting event lasting for several hours . like everywhere else on earth , lightning at lake maracaibo is the result of opposing electrical charges that steadily build up inside storm clouds . once there 's a large enough difference between charges either within the cloud or between the clouds and the earth below , it forms a spark that becomes a lightning bolt . lightning strikes the earth about 350 million times per year , averaging out to eleven strikes a second . we know that thanks to satellites up in space and sensors on the ground . we can also measure the earth 's lightning density , which is the frequency with which lightning flashes in a square kilometer . knowing where lightning strikes and how often reveals the most lightning-rich places on earth . in the polar regions , there may only be one strike per several square kilometers each year . meanwhile , lightning density at the equator averages out to tens of flashes per square kilometer on account of the sun providing more heat to drive storms . yet nowhere can quite compare with lake maracaibo , where lightning strikes an average 250 times per square kilometer , giving it the highest lightning density of any place on earth . a number of factors converge to create the lake 's seemingly everlasting storms . firstly , lake maracaibo lies just ten degrees north of the equator , so there 's a wealth of solar energy available to fuel the storms . thunderstorms also require a supply of water vapor to feed on , and having the warm waters of the caribbean so close by provides an endless supply . finally , the lake 's southern and western edges are bordered by two massive mountain ranges , and as cool winds surge down these slopes , they force up warm air , destabilizing the atmosphere and causing storm clouds to form . together , these ingredients combine to give rise to the most awe-inspiring thunderstorms on the planet , a true sight to behold . centuries ago , sir francis drake may have cursed the lake 's intense illumination , but today , sailors actually embrace this phenomenon . they call it the maracaibo beacon , and use it as a natural lighthouse to illuminate their path across the seas .
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meanwhile , lightning density at the equator averages out to tens of flashes per square kilometer on account of the sun providing more heat to drive storms . yet nowhere can quite compare with lake maracaibo , where lightning strikes an average 250 times per square kilometer , giving it the highest lightning density of any place on earth . a number of factors converge to create the lake 's seemingly everlasting storms .
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in which country will you find the highest lightning density on earth ?
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why does your mouth feel like it 's on fire when you eat a spicy pepper ? and how do you soothe the burn ? why does wasabi make your eyes water ? and how spicy is the spiciest spice ? let 's back up a bit . first , what is spiciness ? even though we often say that something tastes spicy , it 's not actually a taste , like sweet or salty or sour . instead , what 's really happening is that certain compounds in spicy foods activate the type of sensory neurons called polymodal nociceptors . you have these all over your body , including your mouth and nose , and they 're the same receptors that are activated by extreme heat . so , when you eat a chili pepper , your mouth feels like it 's burning because your brain actually thinks it 's burning . the opposite happens when you eat something with menthol in it . the cool , minty compound is activating your cold receptors . when these heat-sensitive receptors are activated , your body thinks it 's in contact with a dangerous heat source and reacts accordingly . this is why you start to sweat , and your heart starts beating faster . the peppers have elicited the same fight-or-flight response with which your body reacts to most threats . but you may have noticed that not all spicy foods are spicy in the same way . and the difference lies in the types of compounds involved . the capsaicin and piperine , found in black pepper and chili peppers , are made up of larger , heavier molecules called alkylamides , and those mostly stay in your mouth . mustard , horseradish , and wasabi are made up of smaller molecules , called isothiocyanates , that easily float up into your sinuses . this is why chili peppers burn your mouth , and wasabi burns your nose . the standard measure of a food 's spiciness is its rating on the scoville scale , which measures how much its capsaicin content can be diluted before the heat is no longer detectable to humans . a sweet bell pepper gets 0 scoville heat units , while tabasco sauce clocks in between 1,200-2,400 units . the race to create the hottest pepper is a constant battle , but two peppers generally come out on top : the trinidad moruga scorpion and the carolina reaper . these peppers measure between 1.5 and 2 million scoville heat units , which is about half the units found in pepper spray . so , why would anyone want to eat something that causes such high levels of pain ? nobody really knows when or why humans started eating hot peppers . archaeologists have found spices like mustard along with human artifacts dating as far back as 23,000 years ago . but they do n't know whether the spices were used for food or medication or just decoration . more recently , a 6,000 year old crockpot , lined with charred fish and meat , also contained mustard . one theory says that humans starting adding spices to food to kill off bacteria . and some studies show that spice developed mostly in warmer climates where microbes also happen to be more prevalent . but why we continue to subject ourselves to spicy food today is still a bit of a mystery . for some people , eating spicy food is like riding rollercoasters ; they enjoy the ensuing thrill , even if the immediate sensation is unpleasant . some studies have even shown that those who like to eat hot stuff are more likely to enjoy other adrenaline-rich activities , like gambling . the taste for spicy food may even be genetic . and if you 're thinking about training a bit , to up your tolerance for spice , know this : according to some studies , the pain does n't get any better . you just get tougher . in fact , researchers have found that people who like to eat spicy foods do n't rate the burn any less painful than those who do n't . they just seem to like the pain more . so , torment your heat receptors all you want , but remember , when it comes to spicy food , you 're going to get burned .
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why does wasabi make your eyes water ? and how spicy is the spiciest spice ? let 's back up a bit .
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using what you ’ ve learned about how spice works , what do you think is the best way to cool your mouth off after eating something spicy ?
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