context
stringlengths 241
19.4k
| questionsrc
stringlengths 34
2.9k
| question
stringlengths 11
1.46k
|
|---|---|---|
translator : andrea mcdonough reviewer : bedirhan cinar why do we see illusions ? i 'm going to tell you about some of my research , where i provided evidence for a different kind of hypothesis than the one that might be in the book on your coffee stand . alright , so let 's look at one of the illusions here . and this is a stand-in for many , many kinds of illusions that are explained by this hypothesis . i 'm just going to walk through it for this particular one . as usual in these things , these two lines are , in fact , parallel , but you perceive them to bow outwards at their centers . at the center where those radial lines are , it 's wider in your visual field than the parts above and below . and this is remarkable , because it 's a remarkably simple stimulus . it 's just a bunch of straight lines . why should one of the most complicated objects in the universe be unable to render this incredibly simple image ? when you want to answer questions like this , you need to ask , well , what might this mean to your brain ? and what your brain is going to think this is , is not some lines on a page . your brain has evolved to handle the kinds of natural stimuli that it encounters in real life . so when does the brain encounter stimuli like this ? well , it seems a bit odd , but in fact , you 've been encountering this stimulus all day long . whenever you move , whenever you move forward , in particular . when you move forward , you get optic flow , flowing outwards in your visual field , like when the enterprise goes into warp . all of these objects flow outwards and they leave trails , or blur lines , on your retina . they 're activating mini-neurons all in a row . so , this is a version of what happens in real life and this another version of what happens in real life all the time . in fact , cartoonists know about this . they put these blur lines in their cartoons and it means to your brain : motion . now , it 's not that in real life you see blur lines . the point is that it 's the stimulus at the back of your eye that has these optic blurs in them , and that 's what tells your brain that you 're moving . when you move forward , your eyes fixate like cameras , like snapshot cameras , it fixates , it fixates , little ( snapshot sound ) camera shots , and each time it fixates when you 're moving forward , you get all this flowing outwards . so when you take a fixation , you end up with this weird optic blur stuff , and it tells you the direction you 're moving . alright , that 's half the story . that 's what this stimulus means . it means that your brain thinks , when it 's looking at the first image , that you 're actually on your way , moving towards the center . it still does n't explain why you should perceive these straight lines as bowed outwards . to understand the rest of the story , you have to understand that our brains are slow . what you would like is that when light hits your eye , then -- ping ! -- immediately you have a perception of what the world is like . but it does n't work that way . it takes about a tenth of a second for your perception to be created . and a tenth of a second does n't sound very long , but it 's a long time in normal behaviors . if you 're moving just at one meter per second , which is fairly slow , then in a tenth of second , you 've moved 10 centimeters . so if you did n't correct for this delay , then anything that you perceived to be within 10 centimeters of you , by the time you perceived it , you would have bumped into it or just passed it . and of course , this is going to be much worse -- ( laughter ) it 's going to be much worse in a situation like this . your perception is behind . what you want is that your perception should look like this . you want your perceptions at any time t to be of the world at time t. but the only way your brain can do that , is that it has to , instead of generating a perception of the way the world was when light hit your retina , it has to do something fancier . it ca n't passively respond and create a best guess , it has to create a best guess about the next moment . what will the world look like in a tenth of a second ? build a perception of that , because by the time your perception of the near future occurs in your brain , the near future will have arrived and you 'll have a perception of the present , which is what you want . in my research , i provided a lot of evidence -- and there 's other research areas that have provided evidence -- that the brain is filled with mechanisms that try to compensate for its slowness . and i 've shown that huge swaths of illusions are explained by this , this just being one example . but let me finish by saying , how exactly does this explain this particular example ? so , the question , really , we have to ask is : how do those two vertical lines in that first stimulus , how do they change in the next moment were i moving towards the center , that all those optical lines are suggesting that i 'm moving . what happens to them ? well , let 's imagine . imagine you 've got a doorway . you 've got a doorway . imagine it 's a cathedral doorway , to make it more concrete -- it 'll be helpful in a second . when you 're very far away from it , the sides are perfectly parallel . but now imagine what happens when you get closer . it all flows outwards in your visual field , flowing outwards . but when you 're really close -- imagine the sides of the doorway are here and here , but if you look up at this cathedral doorway and do your fingers like this , the sides of the doorway are going up , like railroad tracks in the sky . what started off as two parallel lines , in fact , bows outwards at eye level , and does n't go outwards nearly as much above . so in the next moment , you have a shape that 's more like this next picture . the projective geometry -- that is , the way the things project , in fact , change in this way in the next moment . so when you have a stimulus like this , well , your brain has no problem , there 's just two vertical lines and no cues that there 'll be a change in the next moment , so just render it as it is . but if you add cues -- and this is just one of many kinds of cues that can lead to these kinds of illusions , this very strong optic blur cue -- then you 're going to perceive instead exactly how it will appear in the next moment . all of our perceptions are always trying to be about the present , but you have to perceive the future to , in fact , perceive the present . and these illusions are failed perceptions of the future , because they 're just static images on the page , they 're not changing like in real life . and let me just end by showing one illusion here . if i can , i 'll quickly show two . this one 's fun . if you just fixate at the middle there , and make stabbing motions with your head , looming towards it like this . everybody do that . make short , stabbing motions . because i 've added blur to these optic flow lines , your brain says , `` they 're probably already moving , that 's why they 're blurry . '' when you do it , they should be bursting out in your visual field faster than they should . they should n't be moving that much . and a final one i 'll just leave in the background is this . here are the cues of motion , the kinds of cues that you get on your retina when things are moving . you do n't have to do anything -- just look at it . raise your hand if things are moving when they should n't be . it 's weird , right ? but what you have now are the cues that , from your brain 's point of view , you have the stimulus on your eyes , like , `` oh , these things are moving . '' render a perception of what they 'll do in the next moment -- they should be moving and they should have shifted . alright , thank you very much . ( applause )
|
to understand the rest of the story , you have to understand that our brains are slow . what you would like is that when light hits your eye , then -- ping ! -- immediately you have a perception of what the world is like .
|
in your own words , explain why the eye is so complex .
|
the presidency of the united states of america is often said to be one of the most powerful positions in the world . but of all the u.s. presidents accused of misusing that power , only one has left office as a result . does richard nixon deserve to be remembered for more than the scandal that ended his presidency ? find out as we put this disgraced president 's legacy on trial in history vs. richard nixon . `` order , order . now , who 's the defendant today , some kind of crook ? '' `` cough . no , your honor . this is richard milhous nixon , the 37th president of the united states , who served from 1969 to 1974 . '' `` hold on . that 's a weird number of years for a president to serve . '' `` well , you see , president nixon resigned for the good of the nation and was pardoned by president ford , who took over after him . '' `` he resigned because he was about to be impeached , and he did n't want the full extent of his crimes exposed . '' `` and what were these crimes ? '' `` your honor , the watergate scandal was one of the grossest abuses of presidential power in history . nixon 's men broke into the democratic national committee headquarters to wiretap the offices and dig up dirt on opponents for the reelection campaign . '' `` cough it was established that the president did not order this burglary . '' `` but as soon as he learned of it , he did everything to cover it up , while lying about it for months . '' `` uh , yes , but it was for the good of the country . he did so much during his time in office and could have done so much more without a scandal jeopardizing his accomplishments . '' `` uh , accomplishments ? '' `` yes , your honor . did you know it was president nixon who proposed the creation of the environmental protection agency , and signed the national environmental policy act into law ? not to mention the endangered species act , marine mammal protection act , expansion of the clean air act . '' `` sounds pretty progressive of him . '' `` progressive ? hardly . nixon 's presidential campaign courted southern voters through fear and resentment of the civil rights movement . '' `` speaking of civil rights , the prosecution may be surprised to learn that he signed the title ix amendment , banning gender-based discrimination in education , and ensured that desegregation of schools occurred peacefully , and he lowered the voting age to 18 , so that students could vote . '' `` he did n't have much concern for students after four were shot by the national guard at kent state . instead , he called them bums for protesting the vietnam war , a war he had campaigned on ending . '' `` but he did end it . '' `` he ended it two years after taking office . meanwhile , his campaign had sabotaged the previous president 's peace talks , urging the south vietnamese government to hold out for supposedly better terms , which , i might add , did n't materialize . so , he protracted the war for four years , in which 20,000 more u.s. troops , and over a million more vietnamese , died for nothing . '' `` hmm , a presidential candidate interfering in foreign negotiations -- is n't that treason ? '' `` it is , your honor , a clear violation of the logan act of 1799 . '' `` uh , i think we 're forgetting president nixon 's many foreign policy achievements . it was he who normalized ties with china , forging economic ties that continue today . '' `` are we so sure that 's a good thing ? and do n't forget his support of the coup in chile that replaced the democratically-elected president allende with a brutal military dictator . '' `` it was part of the fight against communism . '' `` were n't tyranny and violence the reasons we opposed communism to begin with ? or was it just fear of the lower class rising up against the rich ? '' `` president nixon could n't have predicted the violence of pinochet 's regime , and being anti-communist did n't mean neglecting the poor . he proposed a guaranteed basic income for all american families , still a radical concept today . and he even pushed for comprehensive healthcare reform , just the kind that passed 40 years later . '' `` i 'm still confused about this burglary business . was he a crook or not ? '' `` your honor , president nixon may have violated a law or two , but what was the real harm compared to all he accomplished while in office ? '' `` the harm was to democracy itself . the whole point of the ideals nixon claimed to promote abroad is that leaders are accountable to the people , and when they hold themselves above the law for whatever reason , those ideals are undermined . '' `` and if you do n't hold people accountable to the law , i 'll be out of a job . '' many politicians have compromised some principles to achieve results , but law-breaking and cover-ups threaten the very fabric the nation is built on . those who do so may find their entire legacy tainted when history is put on trial .
|
hardly . nixon 's presidential campaign courted southern voters through fear and resentment of the civil rights movement . '' `` speaking of civil rights , the prosecution may be surprised to learn that he signed the title ix amendment , banning gender-based discrimination in education , and ensured that desegregation of schools occurred peacefully , and he lowered the voting age to 18 , so that students could vote . ''
|
what was nixon 's relationship to the civil rights movement ?
|
10,000 years ago , a deadly virus arose in northeastern africa . the virus spread through the air , attacking the skin cells , bone marrow , spleen , and lymph nodes of its victims . the unlucky infected developed fevers , vomiting , and rashes . 30 % of infected people died during the second week of infection . survivors bore scars and scabs for the rest of their lives . smallpox had arrived . in 1350 b.c. , the first smallpox epidemics hit during the egypt-hittite war . egyptian prisoners spread smallpox to the hittites , which killed their king and devastated his civilization . insidiously , smallpox made its way around the world via egyptian merchants , then through the arab world with the crusades , and all the way to the americas with the spanish and portuguese conquests . since then , it has killed billions of people with an estimated 300 to 500 million people killed in the 20th century alone . but smallpox is not unbeatable . in fact , the fall of smallpox started long before modern medicine . it began all the way back in 1022 a.d . according to a small book , called `` the correct treatment of small pox , '' a buddhist nun living in a famous mountain named o mei shan in the southern providence of sichuan would grind up smallpox scabs and blow the powder into nostrils of healthy people . she did this after noticing that those who managed to survive smallpox never got it again , and her odd treatment worked . the procedure , called variolation , slowly evolved and by the 1700 's , doctors were taking material from sores and putting them into healthy people through four or five scratches on the arm . this worked pretty well as inoculated people would not get reinfected , but it was n't foolproof . up to three percent of people would still die after being exposed to the puss . it was n't until english physician edward jenner noticed something interesting about dairy maids that we got our modern solution . at age 13 , while jenner was apprentice to a country surgeon and apothecary in sodbury , near bristol , he heard a dairy maid say , `` i shall never have smallpox , for i have had cowpox . i shall never have an ugly , pockmarked face . '' cowpox is a skin disease that resembles smallpox and infects cows . later on , as a physician , he realized that she was right , women who got cowpox did n't develop the deadly smallpox . smallpox and cowpox viruses are from the same family . but when a virus infects an unfamiliar host , in this case cowpox infecting a human , it is less virulent , so jenner decided to test whether the cowpox virus could be used to protect against smallpox . in may 1796 , jenner found a young dairy maid , sarah nelmes , who had fresh cowpox lesions on her hand and arm caught from the utters of a cow named blossom . using matter from her pustules , he inoculated james phipps , the eight-year-old son of his gardener . after a few days of fever and discomfort , the boy seemed to recover . two months later , jenner inoculated the boy again , this time with matter from a fresh smallpox lesion . no disease developed , and jenner concluded that protection was complete . his plan had worked . jenner later used the cowpox virus in several other people and challenged them repeatedly with smallpox , proving that they were immune to the disease . with this procedure , jenner invented the smallpox vaccination . unlike variolation , which used actual smallpox virus to try to protect people , vaccination used the far less dangerous cowpox virus . the medical establishment , cautious then as now , deliberated at length over his findings before accepting them . but eventually vaccination was gradually accepted and variolation became prohibited in england in 1840 . after large vaccination campaigns throughout the 19th and 20th centuries , the world health organization certified smallpox 's eradication in 1979 . jenner is forever remembered as the father of immunology , but let 's not forget the dairy maid sarah nelmes , blossom the cow , and james phipps , all heroes in this great adventure of vaccination who helped eradicate smallpox .
|
later on , as a physician , he realized that she was right , women who got cowpox did n't develop the deadly smallpox . smallpox and cowpox viruses are from the same family . but when a virus infects an unfamiliar host , in this case cowpox infecting a human , it is less virulent , so jenner decided to test whether the cowpox virus could be used to protect against smallpox . in may 1796 , jenner found a young dairy maid , sarah nelmes , who had fresh cowpox lesions on her hand and arm caught from the utters of a cow named blossom .
|
how intense were the clinical symptoms of cowpox as compared to smallpox in humans ?
|
can plants talk to each other ? it certainly does n't seem that way . plants do n't have complex sensory or nervous systems like animals do , and they look pretty passive , basking in the sun , and responding instinctively to inputs like light and water . but odd as it sounds , plants can communicate with each other . just like animals , plants produce all kinds of chemical signals in response to their environments , and they can share those signals with each other , especially when they 're under attack . these signals take two routes : through the air , and through the soil . when plant leaves get damaged , whether by hungry insects or an invading lawn mower , they release plumes of volatile chemicals . they 're what 's responsible for the smell of freshly cut grass . certain kinds of plants , like sagebrush and lima beans , are able to pick up on those airborne messages and adjust their own internal chemistry accordingly . in one experiment , sagebrush leaves were deliberately damaged by insects or scissor-wielding scientists . throughout the summer , other branches on the same sagebrush plant got eaten less by insects wandering through , and so did branches on neighboring bushes , suggesting that they had beefed up their anti-insect defenses . even moving the air from above a clipped plant to another one made the second plant more insect-resistant . these airborne cues increase the likelihood of seedling survival , and made adult plants produce more new branches and flowers . but why would a plant warn its neighbors of danger , especially if they 're competing for resources ? well , it might be an accidental consequence of a self-defense mechanism . plants ca n't move information through their bodies as easily as we can , especially if water is scarce . so plants may rely on those airborne chemicals to get messages from one part of a plant to another . nearby plants can eavesdrop on those signals , like overhearing your neighbor sneeze and stocking up on cold medicine . different plants convey those warnings using different chemical languages . individual sagebrush plants in the same meadow release slightly different sets of alarm chemicals . the makeup of that cocktail influences the effectiveness of communication . the more similar two plants ' chemical fingerprints are , the more fluently they can communicate . a plant will be most sensitive to the cues emitted by its own leaves . but because these chemicals seem to be inherited , like human blood types , sagebrush plants communicate more effectively with relatives than with strangers . but sometimes , even other species can benefit . tomato and tobacco plants can both decipher sagebrush warning signals . plants do n't have to rely solely on those airborne broadcasts . signals can travel below the soil surface , too . most plants have a symbiotic relationship with fungi , which colonize the plants ' roots and help them absorb water and nutrients . these fungal filaments form extensive networks that can connect separate plants , creating an underground super highway for chemical messages . when a tomato plant responds to blight by acitvating disease-fighting genes and enzymes , signaling molecules produced by its immune system can travel to a healthy plant and prompt it to turn on its immune system , too . these advance warnings increase the plants chance of survival . bean plants also eavesdrop on each other 's health through these fungal conduits . an aphid investation in one plant triggers its neighbor to ramp up production of compounds that repel aphids and attract aphid-eating wasps . if you think of communication as an exchange of information , then plants seem to be active communicators . they 're sending , receiving , and responding to signals without making a sound , and without brains , noses , dictionaries , or the internet . and if we can learn to speak to them on their terms , we may gain a powerful new tool to protect crops and other valuable species . it all makes you wonder what else are we missing ?
|
plants do n't have to rely solely on those airborne broadcasts . signals can travel below the soil surface , too . most plants have a symbiotic relationship with fungi , which colonize the plants ' roots and help them absorb water and nutrients .
|
plants communicate below the soil surface :
|
as one of the most notorious gangsters in history , al capone presided over a vast and profitable empire of organized crime . when he was finally put on trial , the most he could be convicted of was tax evasion . the nearly $ 100 million a year , that 's 1.4 billion in today 's currency , that capone had earned from illegal gambling , bootlegging , brothels , and extortion , would have served as evidence of his crimes . but the money was nowhere to be found . capone and his associates had hidden it through investments in various businesses whose ultimate ownership could n't be proven , like cash-only laundromats . in fact , those laundromats are part of the reason for the name of this activity , money laundering . money laundering came to be the term for any process that cleans illegally obtained funds of their dirty criminal origins , allowing them to be used within the legal economy . but capone was n't the first to launder money . in fact , this practice is about as old as money itself . merchants hid their riches from tax collecters , and pirates sought to sell their bounty without drawing attention to how they got it . with the recent arrival of virtual currencies , offshore banking , the darknet , and global markets , schemes have become much more complex . although modern money laundering methods vary greatly , most share three basic steps : placement , layering , and integration . placement is where illegally obtained money is converted into assets that seem legitimate . that 's often done by depositing funds into a bank account registered to an anonymous corporation or a professional middleman . this step is where criminals are often most vulnerable to detection since they introduce massive wealth into the financial system seemingly out of nowhere . the second step , layering , involves using multiple transactions to further distance the funds from their origin . this can take the form of transfers between multiple accounts , or the purchase of tradable property , like expensive cars , artwork , and real estate . casinos , where large sums of money change hands every second , are also popular venues for layering . a money launderer may have their gambling balance made available at a casino chain 's locations in other countries , or work with employees to rig games . the last step , integration , allows clean money to re-enter the mainstream economy and to benefit the original criminal . they might invest it into a legal business claiming payment by producing fake invoices , or even start a bogus charity , placing themselves on the board of directors with an exorbitant salary . money laundering itself was n't officially recognized as a federal crime in the united states until 1986 . before that point , the government needed to prosecute a related crime , like tax evasion . from 1986 on , they could confiscate wealth simply by demonstrating that concealment had occurred , which had a positive effect on prosecuting major criminal operations , like drug traffickers . however , a legal shift has raised concerns involving privacy and government surveillance . today , the united nations , national governments , and various nonprofits fight against money laundering , yet the practice continues to play a major role in global crime . and the most high-profile instances of money laundering have involved not just private individuals , but major financial institutions and government officials . no one knows for sure the total amount of money that 's laundered on a yearly basis , but some organizations estimate it to be in the hundreds of billions of dollars .
|
however , a legal shift has raised concerns involving privacy and government surveillance . today , the united nations , national governments , and various nonprofits fight against money laundering , yet the practice continues to play a major role in global crime . and the most high-profile instances of money laundering have involved not just private individuals , but major financial institutions and government officials .
|
what tools can be used to detect money laundering in today ’ s global economy ?
|
what do silk , dna , wood , balloons , and silly putty all have in common ? they 're polymers . polymers are such a big part of our lives that it 's virtually impossible to imagine a world without them , but what the heck are they ? polymers are large molecules made of small units called monomers linked together like the railroad cars from a train . poly means many , and mono means one , and mers or mero means parts . many polymers are made by repeating the same small monomer over and over again while others are made from two monomers linked in a pattern . all living things are made of polymers . some of the organic molecules in organisms are small and simple , having only one of a few functional groups . others , especially those that play structural roles or store genetic information , are macromolecules . in many cases , these macromolecules are polymers . for example , complex carbohydrates are polymers of simple sugars , proteins are polymers of amino acids , and nucleic acids , dna and rna , which contain our genetic information , are polymers of nucleotides . trees and plants are made of the polymer cellulose . it 's the tough stuff you find in bark and stems . feathers , fur , hair , and fingernails are made up of the protein keratin , also a polymer . it does n't stop there . did you know that the exoskeletons of the largest phylum in the animal kingdom , the arthropods , are made of the polymer chitin ? polymers also form the basis for synthetic fibers , rubbers , and plastics . all synthetic polymers are derived from petroleum oil and manufactured through chemical reactions . the two most common types of reactions used to make polymers are addition reactions and condensation reactions . in addition reactions , monomers simply add together to form the polymer . the process starts with a free radical , a species with an unpaired electron . the free radical attacks and breaks the bonds to form new bonds . this process repeats over and over to create a long-chained polymer . in condensation reactions , a small molecule , such as water , is produced with each chain-extending reaction . the first synthetic polymers were created by accident as by-products of various chemical reactions . thinking they were useless , chemists mostly discarded them . finally , one named leo baekeland decided maybe his useless by-product was n't so useless after all . his work resulted in a plastic that could be permanently squished into a shape using pressure and high temperatures . since the name of this plastic , polyoxybenzylmethylenglycolanhydride , was n't very catchy , advertisers called it bakelite . bakelite was made into telephones , children 's toys , and insulators for electrical devices . with its development in 1907 , the plastics industry exploded . one other familiar polymer , silly putty , was also invented by accident . during world war ii , the united states was in desperate need of synthetic rubber to support the military . a team of chemists at general electric attempted to create one but ended up with a gooey , soft putty . it was n't a good rubber substitute , but it did have one strange quality : it appeared to be extremely bouncy . silly putty was born ! synthetic polymers have changed the world . think about it . could you imagine getting through a single day without using plastic ? but polymers are n't all good . styrofoam , for example , is made mainly of styrene , which has been identified as a possible carcinogen by the environmental protection agency . as styrofoam products are being made , or as they slowly deteriorate in landfills or the ocean , they can release toxic styrene into the environment . in addition , plastics that are created by addition polymerization reactions , like styrofoam , plastic bags , and pvc , are built to be durable and food-safe , but that means that they do n't break down in the environment . millions of tons of plastics are dumped into landfills every year . this plastic does n't biodegrade , it just breaks down into smaller and smaller pieces , affecting marine life and eventually making their way back to humans . polymers can be soft or hard , squishy or solid , fragile or strong . the huge variation between means they can form an incredibly diverse array of substances , from dna to nylon stockings . polymers are so useful that we 've grown to depend on them every day . but some are littering our oceans , cities , and waterways with effects on our health that we 're only beginning to understand .
|
some of the organic molecules in organisms are small and simple , having only one of a few functional groups . others , especially those that play structural roles or store genetic information , are macromolecules . in many cases , these macromolecules are polymers . for example , complex carbohydrates are polymers of simple sugars , proteins are polymers of amino acids , and nucleic acids , dna and rna , which contain our genetic information , are polymers of nucleotides . trees and plants are made of the polymer cellulose .
|
there are four basic kinds of biological macromolecules . they are carbohydrates , lipids , ____________ and nucleic acids .
|
pumpkins are a mighty squash - and they 're actually the exact same species as a lot of other squash . acorn squash , yellow squash , spaghetti squash , and even zucchini . that means a zucchini and a pumpkin can breed and have little babies zumpkins or , maybe ... pumpkinis ? the latin name for pumpkins is cucurbita pepo , which just means gourd melon , a truly uninspired bit of naming . like all fruit , pumpkins are both a trick and a treat – the seeds are hidden inside a delicious , brightly covered package so animals to will eat them , and then spread them around . pumpkin seeds ( or pepitas ) have evolved tough shells that can survive the exciting journey through an animal 's digestive tract . in russia , some believe that eating pumpkin seeds can help get rid of parasitic worms . it 's not clear if that really works in humans but there is a real published study in which pumpkin seeds helped de-worm ostriches . pumpkins come from the americas - they were actually one of the first plants domesticated here 8-10 thousand years ago . when the pilgrims arrived in 1620 they ate a lot of pumpkins . they even wrote a poem about . that rhyme scheme was not great , but maybe that ’ s because the pilgrims were also making a lot of beer with their pumpkins . pumpkin beer was already a thing way back in the 17th century sorry hipsters ! people once thought they could get rid of freckles by putting mashed-up pumpkin on there faces . and in all fairness that probably did distract from the freckles . explorers soon brought pumpkins back to europe . it was only 1697 when a frenchman incorporated a pumpkin into the popular folktale we know as cinderella . that was actually a very specific variety of pumpkin - a red pumpkin – and there are lots of other colors . yellow , white , even blue . and all pumpkins start out green – their skin is full of green chlorophyll that photosynthesizes just like in a leaf . as the pumpkin ripens , the chlorophyll breaks down , and other pigments like orange carotene become visible . you know how they gas green tomatoes to turn them red ? it 's called ethylene - and its given off by a lot of ripening fruits . so if you have an unripe green pumpkin and you want to change its color , put it in a bag with some old apples and wait a few days . the jack-o-lantern has its roots in europe the story goes that a sinful man named stingy jack tricked the devil to get out of of hell but also was n't allowed into heaven so he was forced to wander the earth with only a single coal for a light . in the british isles , people used turnips to carve their own jack-o-lanterns , but when they got to the americas they must have realized : these will work waaaaay better .
|
it 's not clear if that really works in humans but there is a real published study in which pumpkin seeds helped de-worm ostriches . pumpkins come from the americas - they were actually one of the first plants domesticated here 8-10 thousand years ago . when the pilgrims arrived in 1620 they ate a lot of pumpkins .
|
pumpkins were one of the first plants domesticated in ...
|
almost 2000 years ago , the roman philosopher seneca peered at his book through a glass of water . suddenly , the text below was transformed . the words magically became clear . but it was n't until a millennium later that that same principle would be used to create the earliest glasses . today , glasses can help millions of people with poor vision due to uncorrected refractive errors . the key to understanding what that means lies with the term refraction , the ability of a transparent medium , like glass , water , or the eye to change the direction of light passing through it . the eye has two main refractive surfaces : the cornea and the lens . ideally , these surfaces work together to refract light in a way that accurately focuses light onto the retina , the layer of light-sensitive tissue at the back of the eye that works with the brain to give rise to vision . but many people develop refractive errors , either during childhood as their eyes are growing , or in later life as their eyes age . imperfections in the cornea and lens cause refracted light to be focused in front of or behind the retina , making images appear blurry . people with refractive errors can still see color , movement , and light , but the details of what they 're looking at are out of focus . people experience refractive errors in different ways , owing to differences in their eyes . in some , light refracts too much , and in others , too little . eyes with a focal point in front of the retina are called myopic , or short-sighted . they can see close objects clearly , but those far away are out of focus . but when the focus point is behind the retina , people are hyperopic , or long-sighted . for them , objects close up are unfocused , but distant objects are crystal clear . finally , some people have a cornea with a non-spherical shape that causes astigmatism , a form of out-of-focus vision that makes all objects seem blurred , whether close or far . as we age , our eyes face new challenges . when we 're young , the lens of the eye is flexible and can change shape to bring images into focus , something called accommodation . this keeps objects in focus when we shift our gaze from far to near . but as we get older , the lens becomes less flexible , and ca n't change shape when we want to look at near objects . this is called presbyopia , and it affects adults starting around the age of 40 years . myopia , hyperopia , astigmatism , and presbyopia . each of these is a refractive error . nowadays we can fix them all with glasses or contact lenses , which work by refocusing light so it strikes the retina precisely . it 's even possible to correct vision with surgery using lasers that change the shape of the cornea and alter its refractive properties . but glasses remain the most popular . by using carefully crafted lenses to steer light to exactly the right spot on the retina , a person 's clear vision can be restored . we 've come a long way since seneca 's discovery and the crude glasses of yesteryear . in 1727 , a british optician named edward scarlett developed the modern style of glasses which are kept in place with arms which hook over each ear . today 's glasses take their inspiration from that design , but they 're also much more precise and personal . each pair is tailored for an individual to bring out their unique powers of sight . so if you 're one of the 500 million people with a problem with close or far vision , or both , there 's a pair of glasses out there waiting to reveal a whole new world that 's hiding in plain view .
|
but it was n't until a millennium later that that same principle would be used to create the earliest glasses . today , glasses can help millions of people with poor vision due to uncorrected refractive errors . the key to understanding what that means lies with the term refraction , the ability of a transparent medium , like glass , water , or the eye to change the direction of light passing through it .
|
so many people in the world have uncorrected refractive errors , despite multiple treatments options . why is this ?
|
on a december afternoon in chicago during the middle of world war ii , scientists cracked open the nucleus at the center of the uranium atom and turned nuclear mass into energy over and over again . they did this by creating for the first time a chain reaction inside a new engineering marvel : the nuclear reactor . since then , the ability to mine great amounts of energy from uranium nuclei has led some to bill nuclear power as a plentiful utopian source of electricity . a modern nuclear reactor generates enough electricity from one kilogram of fuel to power an average american household for nearly 34 years . but rather than dominate the global electricity market , nuclear power has declined from an all-time high of 18 % in 1996 to 11 % today . and it 's expected to drop further in the coming decades . what happened to the great promise of this technology ? it turns out nuclear power faces many hurdles , including high construction costs and public opposition . and behind these problems lie a series of unique engineering challenges . nuclear power relies on the fission of uranium nuclei and a controlled chain reaction that reproduces this splitting in many more nuclei . the atomic nucleus is densely packed with protons and neutrons bound by a powerful nuclear force . most uranium atoms have a total of 238 protons and neutrons , but roughly one in every 140 lacks three neutrons , and this lighter isotope is less tightly bound . compared to its more abundant cousin , a strike by a neutron easily splits the u-235 nuclei into lighter , radioactive elements called fission products , in addition to two to three neutrons , gamma rays , and a few neutrinos . during fission , some nuclear mass transforms into energy . a fraction of the newfound energy powers the fast-moving neutrons , and if some of them strike uranium nuclei , fission results in a second larger generation of neutrons . if this second generation of neutrons strike more uranium nuclei , more fission results in an even larger third generation , and so on . but inside a nuclear reactor , this spiraling chain reaction is tamed using control rods made of elements that capture excess neutrons and keep their number in check . with a controlled chain reaction , a reactor draws power steadily and stably for years . the neutron-led chain reaction is a potent process driving nuclear power , but there 's a catch that can result in unique demands on the production of its fuel . it turns out , most of the neutrons emitted from fission have too much kinetic energy to be captured by uranium nuclei . the fission rate is too low and the chain reaction fizzles out . the first nuclear reactor built in chicago used graphite as a moderator to scatter and slow down neutrons just enough to increase their capture by uranium and raise the rate of fission . modern reactors commonly use purified water as a moderator , but the scattered neutrons are still a little too fast . to compensate and keep up the chain reaction , the concentration of u-235 is enriched to four to seven times its natural abundance . today , enrichment is often done by passing a gaseous uranium compound through centrifuges to separate lighter u-235 from heavier u-238 . but the same process can be continued to highly enrich u-235 up to 130 times its natural abundance and create an explosive chain reaction in a bomb . methods like centrifuge processing must be carefully regulated to limit the spread of bomb-grade fuel . remember , only a fraction of the released fission energy goes into speeding up neutrons . most of the nuclear power goes into the kinetic energy of the fission products . those are captured inside the reactor as heat by a coolant , usually purified water . this heat is eventually used to drive an electric turbine generator by steam just outside the reactor . water flow is critical not only to create electricity , but also to guard against the most dreaded type of reactor accident , the meltdown . if water flow stops because a pipe carrying it breaks , or the pumps that push it fail , the uranium heats up very quickly and melts . during a nuclear meltdown , radioactive vapors escape into the reactor , and if the reactor fails to hold them , a steel and concrete containment building is the last line of defense . but if the radioactive gas pressure is too high , containment fails and the gasses escape into the air , spreading as far and wide as the wind blows . the radioactive fission products in these vapors eventually decay into stable elements . while some decay in a few seconds , others take hundreds of thousands of years . the greatest challenge for a nuclear reactor is to safely contain these products and keep them from harming humans or the environment . containment does n't stop mattering once the fuel is used up . in fact , it becomes an even greater storage problem . every one to two years , some spent fuel is removed from reactors and stored in pools of water that cool the waste and block its radioactive emissions . the irradiated fuel is a mix of uranium that failed to fission , fission products , and plutonium , a radioactive material not found in nature . this mix must be isolated from the environment until it has all safely decayed . many countries propose deep time storage in tunnels drilled far underground , but none have been built , and there 's great uncertainty about their long-term security . how can a nation that has existed for only a few hundred years plan to guard plutonium through its radioactive half-life of 24,000 years ? today , many nuclear power plants sit on their waste , instead , storing them indefinitely on site . apart from radioactivity , there 's an even greater danger with spent fuel . plutonium can sustain a chain reaction and can be mined from the waste to make bombs . storing spent fuel is thus not only a safety risk for the environment , but also a security risk for nations . who should be the watchmen to guard it ? visionary scientists from the early years of the nuclear age pioneered how to reliably tap the tremendous amount of energy inside an atom - as an explosive bomb and as a controlled power source with incredible potential . but their successors have learned humbling insights about the technology 's not-so-utopian industrial limits . mining the subatomic realm makes for complex , expensive , and risky engineering .
|
and it 's expected to drop further in the coming decades . what happened to the great promise of this technology ? it turns out nuclear power faces many hurdles , including high construction costs and public opposition . and behind these problems lie a series of unique engineering challenges .
|
nuclear science is relatively well understood but the technology has proven hard to build and operate . how does the example of nuclear power lead you to think about the relationship between scientific research and everyday technology ?
|
translator : andrea mcdonough reviewer : bedirhan cinar one of the grandest scientific tools ever made by mankind is called an atom smasher . and i mean literally grand . the biggest one ever built , the large hadron collider , or lhc , is a ring with a circumference of about 18 miles . that 's more than the entire length of manhattan . so what is an atom smasher ? it is a device that collides atomic nuclei together at extremely high energy . the most powerful one scientists have ever built can heat matter to the hottest temperatures ever achieved , temperatures last seen at a trillionth of second after the universe began . our accelerators are full of engineering superlatives . the beam-containing region of the lhc is a vacuum , with lower pressure than what surrounds the international space station , and is 456 degrees fahrenheit below zero , colder than the temperature of deepest space . a previous accelerator sitting in the lhc tunnel holds the world record for velocity , accelerating an electron to a speed so fast that if it were to race a photon of light , it would take about 14 minutes for the photon to get a lead of about 10 feet . if that does n't impress you , remember the photon is fastest thing in the universe , it goes about 186,000 miles per second . so how do these subatomic particle accelerators work ? well , they use electric fields . electric fields make charged particles move in the same way that gravity will pull a dropped baseball . the force from the electric field will pull a particle to make it move . the speed will continue to increase until the charged particle is moving incredibly fast . a simple particle accelerator can be made by hooking two parallel metal plates to a battery . the charge from the battery moves on to the two metal plates and makes an electric field that pulls the particle along . and that 's it , you got a particle accelerator . the problem is that an accelerator built this way is very weak . building a modern accelerator like the lhc this way would take over five trillion standard d-cell batteries . so scientists use much stronger batteries and put them one after another . an earlier accelerator used this method and was about a mile long and was equivalent to 30 billion batteries . however , to make an accelerator that is equivalent to five trillion batteries would require an accelerator 150 miles long . scientists needed another way . while electric fields would make a particle go faster , magnetic fields make them move in a circular path . if you put an electric field along the circle , you do n't need to use miles of electric fields , you can use a single electric field over and over again . the beams go around the circle , and each time they gain more energy . so very high-energy accelerators consist of a short region with accelerating electric fields , combined with long series of magnets that guide the particles in a circle . the strength of the magnets and the radius of the circular path determines the maximum energy of the beam . once the beam is zooming along , then the real fun begins , the smashing . the reason physicists want to get those particles moving so fast is so that they can slam them into one another . these collisions can teach us about the fundamental rules that govern matter , but they 'd be impossible without the feat of engineering that is the particle accelerator .
|
that 's more than the entire length of manhattan . so what is an atom smasher ? it is a device that collides atomic nuclei together at extremely high energy .
|
what is the purpose of an atom smasher ?
|
has anyone ever told you , `` stand up straight ! '' or scolded you for slouching at a family dinner ? comments like that might be annoying , but they 're not wrong . your posture , the way you hold your body when you 're sitting or standing , is the foundation for every movement your body makes , and can determine how well your body adapts to the stresses on it . these stresses can be things like carrying weight , or sitting in an awkward position . and the big one we all experience all day every day : gravity . if your posture is n't optimal , your muscles have to work harder to keep you upright and balanced . some muscles will become tight and inflexbile . others will be inhibited . over time , these dysfunctional adaptations impair your body 's ability to deal with the forces on it . poor posture inflicts extra wear and tear on your joints and ligaments , increases the likelihood of accidents , and makes some organs , like your lungs , less efficient . researchers have linked poor posture to scoliosis , tension headaches , and back pain , though it is n't the exclusive cause of any of them . posture can even influence your emotional state and your sensitivity to pain . so there are a lot of reasons to aim for good posture . but it 's getting harder these days . sitting in an awkward position for a long time can promote poor posture , and so can using computers or mobile devices , which encourage you to look downward . many studies suggest that , on average , posture is getting worse . so what does good posture look like ? when you look at the spine from the front or the back , all 33 vertebrae should appear stacked in a straight line . from the side , the spine should have three curves : one at your neck , one at your shoulders , and one at the small of your back . you are n't born with this s-shaped spine . babies ' spines just have one curve like a `` c. '' the other curves usually develop by 12-18 months as the muscles strengthen . these curves help us stay upright and absorb some of the stress from activities like walking and jumping . if they are aligned properly , when you 're standing up , you should be able to draw a straight line from a point just in front of your shoulders , to behind your hip , to the front of your knee , to a few inches in front of your ankle . this keeps your center of gravity directly over your base of support , which allows you to move efficiently with the least amount of fatigue and muscle strain . if you 're sitting , your neck should be vertical , not tilted forward . your shoulders should be relaxed with your arms close to your trunk . your knees should be at a right angle with your feet flat on the floor . but what if your posture is n't that great ? try redesigning your environment . adjust your screen so it 's at or slightly below eyelevel . make sure all parts of your body , like your elbows and wrists , are supported , using ergonomic aids if you need to . try sleeping on your side with your neck supported and with a pillow between your legs . wear shoes with low heels and good arch support , and use a headset for phone calls . it 's also not enough to just have good posture . keeping your muscles and joints moving is extremely important . in fact , being stationary for long periods with good posture can be worse than regular movement with bad posture . when you do move , move smartly . keep anything you 're carrying close to your body . backpacks should be in contact with your back carried symetrically . if you sit a lot , get up and move around on occassion , and be sure to exercise . using your muscles will keep them strong enough to support you effectively , on top of all the other benefits to your joints , bones , brain and heart . and if you 're really worried , check with a physical therapist , because yes , you really should stand up straight .
|
others will be inhibited . over time , these dysfunctional adaptations impair your body 's ability to deal with the forces on it . poor posture inflicts extra wear and tear on your joints and ligaments , increases the likelihood of accidents , and makes some organs , like your lungs , less efficient .
|
which force on our bodies do we have to deal with all the time ?
|
translator : andrea mcdonough reviewer : bedirhan cinar we talk about inventions and innovation as though the best things out there are the internet , ipads , or smart phones . or perhaps more simply , trains , planes , and automobiles . which one is most important , the best , or the greatest ? which one has had the most impact on society ? today the debate would probably be in favor of computer technology , but is it ? well , some would say , `` nope , not really , it 's farming . '' where would we be if we did n't have it ? give up ? we would still be hunting and gathering with little time to invent anything , let alone the internet . that 's right , farming is the seed of civilization . not quite literally , but without early man 's discovery of using seeds to grow grain , we would n't have much of anything we have today . growing your own food changed everything . sure , hunting and gathering worked just fine for tens of thousands of years , but you could n't do much else - no time . but when hunters and gatherers started planting seeds , they began to farm . with farming came animals , and with animals came settling down and staying in one location . so , how does this have anything to do with invention and innovation ? everything . anyone who 's ever farmed , even if it 's planting a half dozen tomato plants in your backyard , knows that you usually harvest way more than you could possibly eat , a surplus . farming yielded plenty of food , with enough to store , trade , and eat . in other words , not everyone needed to be farmers . therefore , this allowed other people , non-farmers , to do other things such as make tools , craft pottery , and build homes . farming and food surpluses led to the division of labor . this is still thousands of years ago , so life was n't easy . but with so many people contributing to the community , small villages began to develop . as the population of villages expanded , so did the needs of the people . things got complicated . but , civilization is just that - advanced , complex societies . and without farming , they would not exist . villages increased in size , eventually becoming the first cities . cities are just one of the basic features of a civilization , the others include central government , system of writing , organized religion , art and architecture , urban planning of roads , bridges , and public works , social classes , and different jobs . developing expertise in various types of occupations allowed for innovative ways of doing things , producing new products , or making advancements in technology . as civilizations became more complex , new ways of doing things were needed . some were out of necessity . others because people had ideas . the sharing of ideas and technology led to the growth of things we readily use today , like the internet . so without farming , we 'd still be hunting and gathering . no video , no computers , and certainly no world wide web .
|
not quite literally , but without early man 's discovery of using seeds to grow grain , we would n't have much of anything we have today . growing your own food changed everything . sure , hunting and gathering worked just fine for tens of thousands of years , but you could n't do much else - no time .
|
agriculture , or growing plants and raising animals for food , developed in several regions of the world around the same time and changed human society forever . explain the effects this had on the typical way of life for hunter-gatherers .
|
translator : andrea mcdonough reviewer : bedirhan cinar when we think about learning , we often picture students in a classroom or lecture hall , books open on their desks , listening intently to a teacher or professor in the front of the room . but in psychology , learning means something else . to psychologists , learning is a long-term change in behavior that 's based on experience . two of the main types of learning are called classical conditioning and operant , or instrumental , conditioning . let 's talk about classical conditioning first . in the 1890 's , a russian physiologist named ivan pavlov did some really famous experiments on dogs . he showed dogs some food and rang a bell at the same time . after a while , the dogs would associate the bell with the food . they would learn that when they heard the bell , they would get fed . eventually , just ringing the bell made the dogs salivate . they learned to expect food at the sound of a bell . you see , under normal conditions , the sight and smell of food causes a dog to salivate . we call the food an unconditioned stimulus , and we call salivation the unconditioned response . nobody trains a dog to salivate over some steak . however , when we pair an unconditioned stimulus like food with something that was previously neutral , like the sound of a bell , that neutral stimulus becomes a conditioned stimulus . and so classical conditioning was discovered . we see how this works with animals , but how does it work with humans ? in exactly the same way . let 's say that one day you go to the doctor to get a shot . she says , `` do n't worry , this wo n't hurt a bit , '' and then gives you the most painful shot you 've ever had . a few weeks later you go to the dentist for a check-up . he starts to put a mirror in your mouth to examine your teeth , and he says , `` do n't worry , this wo n't hurt a bit . '' even though you know the mirror wo n't hurt , you jump out of the chair and run , screaming from the room . when you went to get a shot , the words , `` this wo n't hurt a bit , '' became a conditioned stimulus when they were paired with pain of the shot , the unconditioned stimulus , which was followed by your conditioned response of getting the heck out of there . classical conditioning in action . operant conditioning explains how consequences lead to changes in voluntary behavior . so how does operant conditioning work ? there are two main components in operant conditioning : reinforcement and punishment . reinforcers make it more likely that you 'll do something again , while punishers make it less likely . reinforcement and punishment can be positive or negative , but this does n't mean good and bad . positive means the addition of a stimulus , like getting dessert after you finish your veggies , and negative means the removal of a stimulus , like getting a night of no homework because you did well on an exam . let 's look at an example of operant conditioning . after eating dinner with your family , you clear the table and wash the dishes . when you 're done , your mom gives you a big hug and says , `` thank you for helping me . '' in this situation , your mom 's response is positive reinforcement if it makes you more likely to repeat the operant response , which is to clear the table and wash the dishes . operant conditioning is everywhere in our daily lives . there are n't many things we do that have n't been influenced at some point by operant conditioning . we even see operant conditioning in some extraordinary situations . one group of scientists showed the power of operant conditioning by teaching pigeons to be art connoisseurs . using food as a positive reinforcer , scientists have taught pigeons to select paintings by monet over those by picasso . when showed works of other artists , scientists observed stimulus generalization as the pigeons chose the impressionists over the cubists . maybe next they 'll condition the pigeons to paint their own masterpieces .
|
when you went to get a shot , the words , `` this wo n't hurt a bit , '' became a conditioned stimulus when they were paired with pain of the shot , the unconditioned stimulus , which was followed by your conditioned response of getting the heck out of there . classical conditioning in action . operant conditioning explains how consequences lead to changes in voluntary behavior .
|
in your own words , give a brief distinction between classical and operant conditioning .
|
gravity . it controls the universe . everything attracts everything else . ouch ! including you . ow ! in this final lesson , we 'll explore what gravity means for space-time , or rather what space-time means for gravity . until now , we 've been dealing with things moving at constant speeds , with straight world lines in space-time . but once you add gravity , if you measure a speed at one moment , then again a bit later , the speed may have changed . in other words , as i discovered , gravity causes acceleration , so we need the world line to look different from one moment to the next . as we saw in the last lesson , the correct way to tilt an object 's world line is using a lorentz transformation : einstein 's stretch and squash trick . so , to map out what gravity is doing to tom 's motion , we need to create a whole load of little patches of space-time , each transformed by different amounts . so that my world line is at a different angle in each one . and then , we 're ready to stitch everything together . we assemble a cozy quilt of space-time where world lines look curved . where the world lines join , the objects collide . by making these connections between the patches , a curvature gets built into space-time itself . but einstein 's true genius was to describe precisely how each patch is stretched and squashed according to nearby mass and energy . the mere presence of stuff curves the space-time , and curving space-time moves the stuff around . this is gravity , according to einstein . previously , isaac newton had explained gravity using the ideas of force and acceleration , without any wibbily wobbly space-time , and that did pretty well . but einstein 's theory does just slightly better at predicting , for example , the orbit of mercury around the sun , or the way that light rays are deflected by massive objects . more importantly , einstein 's theory predicts things that simply do n't exist in older theories where space , time and gravity were separate . the stitching can leave wrinkles in the space-time material . these are called gravitational waves , which should be detectable as tiny , repetitive , subtle squashes and stretches in space . so we 're building experiments to check if they are there . in the meantime , indirect evidence , most recently in the polarization patterns of light left over from the big bang , strongly suggest that they are . but despite einstein 's successes , when too much stuff gets concentrated in too small a space , like in a black hole , the curvature of space-time becomes so large , that his equations collapse . we need a new picture of space-time that incorporates quantum mechanics to unlock the secret at the heart of black holes . which means there 's plenty more to be discovered about space , time , and space-time in the future .
|
previously , isaac newton had explained gravity using the ideas of force and acceleration , without any wibbily wobbly space-time , and that did pretty well . but einstein 's theory does just slightly better at predicting , for example , the orbit of mercury around the sun , or the way that light rays are deflected by massive objects . more importantly , einstein 's theory predicts things that simply do n't exist in older theories where space , time and gravity were separate .
|
the precise orbit of mercury around the sun is significant because ________ .
|
translator : andrea mcdonough reviewer : bedirhan cinar you look down and see a yellow pencil lying on your desk . your eyes , and then your brain , are collecting all sorts of information about the pencil : its size , color , shape , distance , and more . but , how exactly does this happen ? the ancient greeks were the first to think more or less scientifically about what light is and how vision works . some greek philosophers , including plato and pythagoras , thought that light originated in our eyes and that vision happened when little , invisible probes were sent to gather information about far-away objects . it took over a thousand years before the arab scientist , alhazen , figured out that the old , greek theory of light could n't be right . in alhazen 's picture , your eyes do n't send out invisible , intelligence-gathering probes , they simply collect the light that falls into them . alhazen 's theory accounts for a fact that the greek 's could n't easily explain : why it gets dark sometimes . the idea is that very few objects actually emit their own light . the special , light-emitting objects , like the sun or a lightbulb , are known as sources of light . most of the things we see , like that pencil on your desk , are simply reflecting light from a source rather than producing their own . so , when you look at your pencil , the light that hits your eye actually originated at the sun and has traveled millions of miles across empty space before bouncing off the pencil and into your eye , which is pretty cool when you think about it . but , what exactly is the stuff that is emitted from the sun and how do we see it ? is it a particle , like atoms , or is it a wave , like ripples on the surface of a pond ? scientists in the modern era would spend a couple of hundred years figuring out the answer to this question . isaac newton was one of the earliest . newton believed that light is made up of tiny , atom-like particles , which he called corpuscles . using this assumption , he was able to explain some properties of light . for example , refraction , which is how a beam of light appears to bend as it passes from air into water . but , in science , even geniuses sometimes get things wrong . in the 19th century , long after newton died , scientists did a series of experiments that clearly showed that light ca n't be made up of tiny , atom-like particles . for one thing , two beams of light that cross paths do n't interact with each other at all . if light were made of tiny , solid balls , then you would expect that some of the particles from beam a would crash into some of the particles from beam b . if that happened , the two particles involved in the collision would bounce off in random directions . but , that does n't happen . the beams of light pass right through each other as you can check for yourself with two laser pointers and some chalk dust . for another thing , light makes interference patterns . interference patterns are the complicated undulations that happen when two wave patterns occupy the same space . they can be seen when two objects disturb the surface of a still pond , and also when two point-like sources of light are placed near each other . only waves make interference patterns , particles do n't . and , as a bonus , understanding that light acts like a wave leads naturally to an explanation of what color is and why that pencil looks yellow . so , it 's settled then , light is a wave , right ? not so fast ! in the 20th century , scientists did experiments that appear to show light acting like a particle . for instance , when you shine light on a metal , the light transfers its energy to the atoms in the metal in discrete packets called quanta . but , we ca n't just forget about properties like interference , either . so these quanta of light are n't at all like the tiny , hard spheres newton imagined . this result , that light sometimes behaves like a particle and sometimes behaves like a wave , led to a revolutionary new physics theory called quantum mechanics . so , after all that , let 's go back to the question , `` what is light ? '' well , light is n't really like anything we 're used to dealing with in our everyday lives . sometimes it behaves like a particle and other times it behaves like a wave , but it is n't exactly like either .
|
alhazen 's theory accounts for a fact that the greek 's could n't easily explain : why it gets dark sometimes . the idea is that very few objects actually emit their own light . the special , light-emitting objects , like the sun or a lightbulb , are known as sources of light . most of the things we see , like that pencil on your desk , are simply reflecting light from a source rather than producing their own .
|
who hypothesized that light was not perceived by tiny probes released from the eyes , but rather by sensing the light emitted by objects outside of the body ?
|
translator : andrea mcdonough reviewer : bedirhan cinar i got in my first car accident when i was sixteen . i had just gotten my license and i was driving home when a car pulled into the intersection and bang ! it hit me . it had happened that quick . bang ! but when i play that memory back , it does n't take two seconds . i see the tires of the car rolling through the stop sign , i have time to think , `` you know , i think that car is going to hit me . '' i see the right-hand corner of the hood crumple up like tin foil , i see the red paint flake off and drift off into the air , i can see all of that , like it 's happening in slow motion . in my memory , that experience takes ten seconds . but why ? why did that memory play back longer than the actual time it took ? this is an interesting phenomenon and it 's not just for car accidents , a roller coaster , or a first kiss . these events seem to take longer than they actually take . but why ? and when it comes to writing about that experience , how do i get that peculiar feeling across ? how do i slow down time as a writer ? to get the answer , we have to visit hollywood . you see , the way filmmakers create slow motion will tell us a lot about how writers can create slow motion . first , let 's remember how film works . when the camera turns on , it 's not recording motion , it 's taking lots and lots of individual pictures . then when those pictures are played back in the projector , they blend together and create the appearance of motion , like a flip book . so , let 's imagine that a camera man needs to film his actress skipping through a field of daisies in regular motion . ready , action . she skips across the field , he records it , and ... cut . let 's say for the sake of easy math that our camera man took 50 pictures , 50 little frames on that length of film . now , let 's take that film and play it back at the rate of 50 frames per 5 seconds . this rate is constant , the projector will always go at the same speed . it 's easy , we got 50 frames , so our film takes 5 seconds . she skips across the field ... ... and cut ! so , then , how do we slow down time in film ? how do we create slow motion ? maybe this is a surprise , but we do n't take less pictures , we take more pictures . ready , action ! she skips across the field , he records it , and cut . now we have a lot of film , a long length , let 's say 100 frames long . now , when we play it back , it takes a longer time to get through , and there 's the actress in slow motion . skipping through the field of daisies ! which brings us now to writing . when you 're writing a narrative , you may want to use slow motion in one of your scenes . it 's a cool effect , just like it is in hollywood , and it draws the reader 's attention to important moments . well , here 's how you do it . you see , when we read , our brain makes the words into pictures and the pictures blend into action . so what we read is what we see in the time it takes us to read it . for example , imagine you 're writing a narrative about your game-winning free throw in the championship game . here 's a moment as a writer that you might want to slow down time to really capture the second-by-second tension produced by the scene . you concentrate , you put the pencil to paper , you really want to slow down time , you write , `` i shot the ball in the hoop . time slowed down . then we won . '' to read that , takes two seconds ; therefore , your reader imagines a scene that takes two seconds . ball goes up , comes down , done . see , even though you wrote , `` time slowed down , '' you did n't achieve that effect for your reader . just saying it does n't make it happen . now , let 's take what we make about film , time slows down with more pictures , and try again . this time write a lot more . `` i bent my knees and held the ball loosely . letting the ball bounce on the floor once more , i gathered my thoughts . this was the moment . my right arm extended as i released the ball with a gentle flick , it rotated slightly as it arched toward the rim . i held my breath . the ball nudged the back rim , falling through the net with a gentle , satisfying swish . and the crowd exploded from their seats . '' see , we just slowed down time through our writing . the bottom line is this : there are moments in life that take longer than they actually take . when you 're planning out your narrative , think about those moments , those snippets of life that took longer than the watch : the moment of hearing bad news , the moment of hearing good news , the moment of exhilaration when you realize you hit the jump , or the moment when you realize you are n't going to land it . once you identify these moments in your narrative , you can use this effect of slow motion when you write . just remember , it 's not enough to say , `` time slowed down '' and it 's not enough to throw a couple adjectives in a sentence and call it done either . descriptive writing is good writing , that 's true . but if you want to express the feeling of slow motion in life , you have to actually take up more physical space on the page , use more film so to speak . in doing so , you will create tension and keep your reader interested . and that way , the next time you write , you 'll control the camera of your own writing .
|
and the crowd exploded from their seats . '' see , we just slowed down time through our writing . the bottom line is this : there are moments in life that take longer than they actually take .
|
what parallel does sitze make about slowing down time in writing ?
|
nicolas steno is rarely heard of outside intro to geology , but anyone hoping to understand life on earth should see how steno expanded and connected those very concepts : earth , life , and understanding . born niels stensen in 1638 denmark , son of a goldsmith , he was a sickly kid whose school chums died of plague . he survived to cut up corpses as an anatomist , studying organs shared across species . he found a duct in animal skulls that sends saliva to the mouth . he refuted descartes ' idea that only humans had a pineal gland , proving it was n't the seat of the soul , arguably , the debut of neuroscience . most remarkable for the time was his method . steno never let ancient texts , aristotelian metaphysics , or cartesian deductions overrule empirical , experimental evidence . his vision , uncluttered by speculation or rationalization , went deep . steno had seen how gallstones form in wet organs by accretion . they obeyed molding principles he knew from the goldsmith trade , rules useful across disciplines for understanding solids by their structural relationships . later , the grand duke of tuscany had him dissect a shark . its teeth resembled tongue stones , odd rocks seen inside other rocks in malta and the mountains near florence . pliny the elder , old roman naturalist , said these fell from the sky . in the dark ages , folks said they were snake tongues , petrified by saint paul . steno saw that tongue stones were shark teeth and vice versa , with the same signs of structural growth . figuring similar things are made in similar ways , he argued the ancient teeth came from ancient sharks in waters that formed rock around the teeth and became mountains . rock layers were once layers of watery sediment , which would lay out horizontally , one atop another , oldest up to newest . if layers were deformed , tilted , cut by a fault or a canyon , that change came after the layer formed . sounds simple today ; back then , revolutionary . he 'd invented stratigraphy and laid geology 's ground work . by finding one origin for shark teeth from two eras by stating natural laws ruling the present also ruled the past , steno planted seeds for uniformitarianism , the idea that the past was shaped by processes observable today . in the 18th and 19th centuries , english uniformitarian geologists , james hutton and charles lyell , studied current , very slow rates of erosion and sedimentation and realized the earth had to be way older than the biblical guestimate , 6000 years . out of their work came the rock cycle , which combined with plate tectonics in the mid-twentieth century to give us the great molten-crusting , quaking , all-encircling theory of the earth , from a gallstone to a 4.5 billion-year-old planet . now think bigger , take it to biology . say you see shark teeth in one layer and a fossil of an organism you 've never seen under that . the deeper fossil 's older , yes ? you now have evidence of the origin and extinction of species over time . get uniformitarian . maybe a process still active today caused changes not just in rocks but in life . it might also explain similarities and differences between species found by anatomists like steno . it 's a lot to ponder , but charles darwin had the time on a long trip to the galapagos , reading a copy of his friend charles lyell 's `` principles of geology , '' which steno sort of founded . sometimes giants stand on the shoulders of curious little people . nicolas steno helped evolve evolution , broke ground for geology , and showed how unbiased , empirical observation can cut across intellectual borders to deepen our perspective . his finest accomplishment , though , may be his maxim , casting the search for truth beyond our senses and our current understanding as the pursuit of the beauty of the as yet unknown . beautiful is what we see , more beautiful is what we know , most beautiful , by far , is what we do n't .
|
nicolas steno is rarely heard of outside intro to geology , but anyone hoping to understand life on earth should see how steno expanded and connected those very concepts : earth , life , and understanding . born niels stensen in 1638 denmark , son of a goldsmith , he was a sickly kid whose school chums died of plague .
|
steno ’ s stratigraphy was a piece of the puzzle that led to the theory of the earth . think of all you know about the earth ’ s geology . what are all the other small questions you need to answer before you get to your current understanding ( however rough ) of how the earth works ?
|
thousands of years in the making , what began as part of a religious festival honoring the greek god zeus in the rural greek town of olympia has today become the greatest show of sporting excellence on earth . the inception date in 776 bc became the basis for the greek 's earliest calendar , where time was marked in four-year increments called olympiads . what could it be ? why , it 's the olympic games , of course . competition fosters excellence , or so thought the ancient greeks . in addition to sporting events , contests were held for music , singing , and poetry . you can read about them all yourself in classical literary works , like homer 's `` iliad '' and virgil 's `` aeneid . '' even mythical heroes appreciate a good contest every now and then , would n't you say ? for the first thirteen games , the ancient greek olympics featured just one event , the two hundred yard dash . but over time , new exciting contests , like boxing , chariot and mule racing , and even a footrace where the competitors wore a full suit of armor enticed many hopeful champions into the olympic stadium . the combined running , jumping , wrestling , javelin throwing , and hurling the discus events known as the pentathlon inspired world-class competition , and the pankration , a no holds barred fight where only biting and eye-gouging were prohibited , ensured the toughest men were victorious . and victorious they were . nobody tops the local baker coroebus , who 776 bc became the very first olympic champion . and we 'll never forget orsippus of megara , the 720 bc olympic victor tore away his loincloth so he could race unimpeded , inaugurating the ancient greek tradition of competing in the nude . now there 's a winning streak , if ever we 've seen one . but all good things must end . in 391 ad , the christian roman emperor theodosius banned pagan practices , so the world soon bid a fond farewell to the olympic games . but just like those early pankration athletes , you ca n't keep a good one down , and 1500 years later in 1896 , the modern olympic games kicked off in athens , greece . today , the summer and winter olympics bring international world-class athletes together by the thousands , uniting fans by the billions for the world 's foremost sporting competition . citius , altius , fortius . three cheers for the olympics .
|
citius , altius , fortius . three cheers for the olympics .
|
what ancient place name underlies the word olympics ?
|
why does salt dissolve in water but oil does n't ? well , in a word , chemistry , but that 's not very satisfying , is it ? well , the reason salt dissolves and oil does not comes down to the two big reasons why anything happens at all : energetics and entropy . energetics deals primarily with the attractive forces between things . when we look at oil or salt in water , we focus on the forces between particles on a very , very , very small scale , the molecular level . to give you a sense of this scale , in one glass of water , there are more molecules than known stars in the universe . now , all of these molecules are in constant motion , moving , vibrating , and rotating . what prevents almost all of those molecules from just flying out of the glass are the attractive interactions between molecules . the strength of the interactions between water , itself , and other substances is what we mean when we say energetics . you can think of the water molecules engaging in a constant dance , sort of like a square dance where they constantly and randomly exchange partners . put simply , the ability for substances to interact with water , balanced with how they disrupt how water interacts with itself , plays an important role in explaining why certain things mix well into water and others do n't . entropy basically describes the way things and energy can be arranged based on random motion . for example , think of the air in a room . imagine all the different possible arrangements in space for the trillions of particles that make up the air . some of those arrangments might have all the oxygen molecules over here and all the nitrogen molecules over there , separated . but far more of the possible arrangements have those molecules mixed up with one another . so , entropy favors mixing . energetics deals with attractive forces . and so , if attractive forces are present , the probability of some arrangements can be enhanced , the ones where things are attracted to each other . so , it is always the balance of these two things that determines what happens . on the molecular level , water is comprised of water molecules , made up of two hydrogen atoms and an oxygen atom . as liquid water , these molecules are engaged in a constant and random square dance that is called the hydrogen bonding network . entropy favors keeping the square dance going at all times . there are always more ways that all the water molecules can arrange in a square dance , as compared to if the water molecules did a line dance . so , the square dance constantly goes on . so , what happens when you put salt in the water ? well , on the molecular level , salt is actually made up of two different ions , chlorine and sodium , that are organized like a brick wall . they show up to the dance as a big group in formation and sit on the side at first , shy and a bit reluctant to break apart into individual ions to join the dance . but secretly , those shy dancers just want someone to ask them to join . so , when a water randomly bumps into one of them and pulls them into the dance away from their group , they go . and once they go into the dance , they do n't come back out . and in fact , the addition of the salt ions adds more possible dance positions in the square dance , so it is favored for them to stay dancing with water . now , let 's take oil . with oil , the molecules are sort of interested in dancing with water , so entropy favors them joining the dance . the problem is that oil molecules are wearing gigantic ballgowns , and they 're way bigger than water molecules . so , when an oil molecule gets pulled in , their size is really disruptive to the dance and the random exchange of partners that the waters engage in , a very important part of the dance . in addition , they are not great dancers . the water molecules try to engage the oil molecules in the dance , but they just keep bumping into their dresses and taking up all the room on the dance floor . there are way more ways the waters can dance when the oil gets off the floor , so the waters squeeze out the oil , pushing it back to the bench with the others . pretty soon , when a large number of oils have been squeezed over to the side , they band together to commiserate about how unfair the waters are being and stick together as a group . so , it is this combination of the interactions between molecules and the configurations available to them when they 're moving randomly that dictates whether they mix . in other words , water and oil do n't mix because they just do n't make great dance partners .
|
but far more of the possible arrangements have those molecules mixed up with one another . so , entropy favors mixing . energetics deals with attractive forces .
|
entropy is best described as ________ .
|
gravity . it controls the universe . everything attracts everything else . ouch ! including you . ow ! in this final lesson , we 'll explore what gravity means for space-time , or rather what space-time means for gravity . until now , we 've been dealing with things moving at constant speeds , with straight world lines in space-time . but once you add gravity , if you measure a speed at one moment , then again a bit later , the speed may have changed . in other words , as i discovered , gravity causes acceleration , so we need the world line to look different from one moment to the next . as we saw in the last lesson , the correct way to tilt an object 's world line is using a lorentz transformation : einstein 's stretch and squash trick . so , to map out what gravity is doing to tom 's motion , we need to create a whole load of little patches of space-time , each transformed by different amounts . so that my world line is at a different angle in each one . and then , we 're ready to stitch everything together . we assemble a cozy quilt of space-time where world lines look curved . where the world lines join , the objects collide . by making these connections between the patches , a curvature gets built into space-time itself . but einstein 's true genius was to describe precisely how each patch is stretched and squashed according to nearby mass and energy . the mere presence of stuff curves the space-time , and curving space-time moves the stuff around . this is gravity , according to einstein . previously , isaac newton had explained gravity using the ideas of force and acceleration , without any wibbily wobbly space-time , and that did pretty well . but einstein 's theory does just slightly better at predicting , for example , the orbit of mercury around the sun , or the way that light rays are deflected by massive objects . more importantly , einstein 's theory predicts things that simply do n't exist in older theories where space , time and gravity were separate . the stitching can leave wrinkles in the space-time material . these are called gravitational waves , which should be detectable as tiny , repetitive , subtle squashes and stretches in space . so we 're building experiments to check if they are there . in the meantime , indirect evidence , most recently in the polarization patterns of light left over from the big bang , strongly suggest that they are . but despite einstein 's successes , when too much stuff gets concentrated in too small a space , like in a black hole , the curvature of space-time becomes so large , that his equations collapse . we need a new picture of space-time that incorporates quantum mechanics to unlock the secret at the heart of black holes . which means there 's plenty more to be discovered about space , time , and space-time in the future .
|
so , to map out what gravity is doing to tom 's motion , we need to create a whole load of little patches of space-time , each transformed by different amounts . so that my world line is at a different angle in each one . and then , we 're ready to stitch everything together .
|
what is different about curved worldlines from straight ones ?
|
would n't it be great if we could be invisible ? ha , right ? i mean , we could spy on people without being noticed and do whatever we want without being held responsible . now , magicians have figured out how to utilize full-sized mirrors to bend light in order to create disappearing illusions . scientists have created metamaterials to guide rays of light around tiny , two-dimensional objects . cameras can also film what is behind you and project the image so you appear invisible from the front . however , none of these options can make an object as large as a person appear invisible for all angles and distances while its moving . but if you are truly invisible , as in from within , here are a few problems you may not have thought about before . to move around undetected by other people , you would have to be totally naked . even if it 's freezing outside ! you ca n't carry anything , including your wallet and keys , otherwise people would just see your wallet and keys floating around . drivers and people on the street ca n't see you either , therefore they can and will run into you at some point . oh , and you better not wear any perfume or make any noise breathing , otherwise they 'll know you 're there . and , just because you start off invisible , does n't mean you 'll stay that way . what if someone accidentally spills scolding hot coffee on you ? and what if it rains ? but if you think only liquid can make you visible , you 're wrong . dust consists of dead skin cells from humans , soil particles , and fibers from clothes made from cotton and other materials . dust sticks to the moisture on our skin when we sweat and the tiny hairs on our skin when we are dry . so , even if you are invisible , dust would still land on every part of you . we usually do n't notice the dust on our skin because we ca n't see a thin layer of dust on top of our skin color . but , if you 're invisible , people would see a human-shaped blob of dust walking around with extremely dirty soles . gross ! what do you think the world looks like if you are invisible ? well , the answer is nothing . the reason you ca n't see in the dark is because there is no light . to see an apple , light has to hit the apple and return it to your eyes . then , the retinas in your eyes catch the light reflection for your brain to interpret into the image of an apple . if you 're invisible , then , by definition , light would travel through you or around you instead of bouncing off you for people to see . but that means that retinas in your eyes are not catching the light , either . therefore , your brain has nothing to interpret into an image . can you see your reflection without a mirror to stop the light ? no . so , when you ca n't be seen by others , you also can not see . ouch ! now , have you given any thought as of whether the invisibility is permanent ? if it is , how can you receive medical treatment from a doctor if you 're injured ? the doctor would n't know where to apply ointments or bandages because they can not access your injury . for that matter , you ca n't see it either . i mean , what if you have an illness or an infection ? how can the doctor diagnose you without being able to see the color change or inflammation ? and what if everyone is permanently invisible ? well , think about how boring the world would be without seeing people on the streets , on tv , or at home on your computer like right now . it 's lonely being invisible . now , which superpower physics lesson will you explore next ? shifting body size and content , super speed , flight , super strength , immortality , and invisibility .
|
ouch ! now , have you given any thought as of whether the invisibility is permanent ? if it is , how can you receive medical treatment from a doctor if you 're injured ?
|
what has been achieved so far in our pursuit of invisibility ?
|
translator : andrea mcdonough reviewer : bedirhan cinar deep in the jungles of vietnam , soldiers from both sides battled heat exhaustion and each other for nearly 20 long years . but the key to communist victory was n't weapons or stamina , it was a dirt road . the ho chi minh trail , winding through vietnam , laos , and cambodia , started as a simple network of dirt roads and blossomed into the centerpiece of the winning north vietnamese strategy during the vietnam war , supplying weapons , troops , and psychological support to the south . the trail was a network of tracks , dirt roads , and river crossings that threaded west out of north vietnam and south along the truong son mountain range between vietnam and laos . the journey to the south originally took six months . but , with engineering and ingenuity , the vietnamese expanded and improved the trail . towards the end of war , as the main roads detoured through laos , it only took one week . here is how it happened . in 1959 , as relations deteriorated between the north and the south , a system of trails was constructed in order to infiltrate soldiers , weapons , and supplies into south vietnam . the first troops moved in single-file along routes used by local ethnic groups , and broken tree branches at dusty crossroads were often all that indicated the direction . initially , most of the communist cadres who came down the trail were southerners by birth who had trained in north vietnam . they dressed like civilian peasants in black , silk pajamas with a checkered scarf . they wore ho chi minh sandals on their feet , cut from truck tires , and carried their ration of cooked rice in elephants ' intestines , a linen tube hung around the body . the conditions were harsh and many deaths were caused by exposure , malaria , and amoebic dysentery . getting lost , starving to death , and the possibility of attacks by wild tigers or bears were constant threats . meals were invariably just rice and salt , and it was easy to run out . fear , boredom , and homesickness were the dominant emotions . and soldiers occupied their spare time by writing letters , drawing sketches , and drinking and smoking with local villagers . the first troops down the trail did not engage in much fighting . and after an exhausting six month trip , arriving in the south was a real highlight , often celebrated by bursting into song . by 1965 , the trip down the trail could be made by truck . thousands of trucks supplied by china and russia took up the task amidst ferocious b-52 bombing and truck drivers became known as pilots of the ground . as traffic down the trail increased , so did the u.s. bombing . they drove at night or in the early morning to avoid air strikes , and watchmen were ready to warn drivers of enemy aircraft . villages along the trail organized teams to guarantee traffic flow and to help drivers repair damage caused by air attacks . their catch cries were , `` everything for our southern brothers ! '' and , `` we will not worry about our houses if the vehicles have not yet gotten through . '' some families donated their doors and wooden beds to repair roads . vietnamese forces even used deception to get the u.s. aircraft to bomb mountainsides in order to make gravel for use in building and maintaining roads . the all-pervading red dust seeped into every nook and cranny . the ho chi minh trail had a profound impact on the vietnam war and it was the key to hanoi 's success . north vietnamese victory was not determined by the battlefields , but by the trail , which was the political , strategic , and economic lynchpin . americans recognized its achievement , calling the trail , `` one of the great achievements in military engineering of the 20th century . '' the trail is a testimony to the strength of will of the vietnamese people , and the men and women who used the trail have become folk heros .
|
the all-pervading red dust seeped into every nook and cranny . the ho chi minh trail had a profound impact on the vietnam war and it was the key to hanoi 's success . north vietnamese victory was not determined by the battlefields , but by the trail , which was the political , strategic , and economic lynchpin .
|
what did the united states government say about the ho chi minh trail ?
|
back in ancient rome , the philosopher cicero described gratitude as the mother of all virtues . this concept of being thankful has been stressed in religion and philosophy for a long time . back in 1820 scottish philosopher thomas brown defined gratitude as “ that delightful emotion of love to him who has conferred a kindness on us. ” but scientifically , gratitude doesn ’ t qualify as a basic emotion like joy , sadness or anger . there ’ s no universal facial expression for it . as an emotion , gratitude is a little hard to define . today the oxford dictionary defines gratitude as “ the quality or condition of being thankful ; the appreciation of an inclination to return kindness. ” and we ’ ve only really started to study gratitude scientifically in the past 30 years . in a 2015 study , participants were asked to imagine how they would feel if a complete stranger saved their life . i mean , how would you feel ? the participants had to rate how grateful they were to strangers who provided them with gifts of food and clothing – all while they had their brain scanned in an fmri machine . researchers found their ratings of gratitude positively correlated with activity in brain areas associated with fairness and value judgements . it makes sense because gratitude is often thought of as a moral emotion . there are even benefits in just noting how grateful you are . another study asked people to write down three things that went well that day and why for one week . at the end of the week people were slightly happier than at the beginning , and over time , their happiness scores kept improving . after one month they were 5 % happier and after six months they were 9 % happier . just from one week of writing a journal . a similar study with participants with heart disease found that keeping a gratitude journal increased their heart health and quality of sleep , perhaps because it reduces stress . “ counting your blessings ” quite literally makes people happier and healthier . and some people are even hardwired to be more thankful . in a recent study of 77 couples , those with a particular genetic variation that affects the secretion of oxytocin expressed more gratitude towards their partners . oxytocin is thought to play a big role in promoting close social bonds , so gratitude is part of the glue that keeps these relationships together . so if you think it ’ s the thought that counts , think again . science shows there are some pretty amazing benefits to our mind , body and relationships when we say those two small words – thank you .
|
after one month they were 5 % happier and after six months they were 9 % happier . just from one week of writing a journal . a similar study with participants with heart disease found that keeping a gratitude journal increased their heart health and quality of sleep , perhaps because it reduces stress . “ counting your blessings ” quite literally makes people happier and healthier .
|
3. keeping a gratitude journal can
|
rising temperatures and seas , massive droughts , changing landscapes . successfully adapting to climate change is growing increasingly important . for humans , this means using our technological advancement to find solutions , like smarter cities and better water management . but for some plants and animals , adapting to these global changes involves the most ancient solution of all : evolution . evolutionary adaptation usually occurs along time scales of thousands to hundreds of thousands of years . but in cases where species are under especially strong selective conditions , like those caused by rapidly changing climates , adaptive evolution can happen more quickly . in recent decades , we 've seen many plants , animals , and insects relocating themselves and undergoing changes to their body sizes , and the dates they flower or breed . but many of these are plastic , or nonheritable changes to an individual 's physical traits . and there are limits to how much an organism can change its own physiology to meet environmental requirements . that 's why scientists are seeking examples of evolutionary changes coded in species ' dna that are heritable , long-lasting , and may provide a key to their future . take the tawny owl . if you were walking through a wintry forest in northern europe 30 years ago , chances are you 'd have heard , rather than seen , this elusive bird . against the snowy backdrop , its plumage would have been near impossible to spot . today , the landscape is vastly different . since the 1980s , climate change has led to significantly less snowfall , but you 'd still struggle to spot a tawny owl because nowadays , they 're brown . the brown color variant is the genetically dominant form of plumage in this species , but historically , the recessive pale gray variant triumphed because of its selective advantage in helping these predators blend in . however , less snow cover reduces opportunities for camouflage , so lately , this gray color variant has been losing the battle against natural selection . the offspring of the brown color morphs , on the other hand , have an advantage in exposed forests , so brown tawny owls are flourishing today . several other species have undergone similar climate-change-adaptive genetic changes in recent decades . pitcher plant mosquitoes have rapidly evolved to take advantage of the warmer temperatures , entering dormancy later and later in the year . two spot ladybug populations , once comprised of equal numbers of melanic and non-melanic morphs , have now shifted almost entirely to the non-melanic color combination . scientists think that keeps them from overheating . meanwhile , pink salmon have adapted to warmer waters by spawning earlier in the season to protect their sensitive eggs . and wild thyme plants in europe are producing more repellent oils to protect themselves against the herbivores that become more common when it 's warm . these plants and animals belong to a group of about 20 identified species with evolutionary adaptations to rapid climate change , including snapping turtles , wood frogs , knotweed , and silver spotted skipper butterflies . however , scientists hope to discover more species evolving in response to climate change out of 8.7 million species on the planet . for most of our planet 's astounding and precious biodiversity , evolution wo n't be the answer . instead , many of those species will have to rely on us to help them survive a changing world or face extinction . the good news is we already have the tools . across the planet , we 're making on-the-ground decisions that will help entire ecosystems adapt . critical climate refuges are being identified and set aside , and projects are underway to help mobile species move to more suitable climates . existing parks and protected areas are also doing climate change check-ups to help their wildlife cope . fortunately , it 's still within our power to preserve much of the wondrous biodiversity of this planet , which , after all , sustains us in so many ways .
|
critical climate refuges are being identified and set aside , and projects are underway to help mobile species move to more suitable climates . existing parks and protected areas are also doing climate change check-ups to help their wildlife cope . fortunately , it 's still within our power to preserve much of the wondrous biodiversity of this planet , which , after all , sustains us in so many ways .
|
how are humans helping wildlife adapt to climate change ?
|
i love astronomy . you may have noticed . but there ’ s one really frustrating aspect of it : everything we study is really far away . nearly everything we understand about the universe comes from light emitted or reflected by objects . it ’ d be nice if we could get actual samples from them ; physical specimens we could examine in the lab . welp , sometimes the universe can be accommodating , and allows us to hold it in our hands . cambot , can we get this up on still store ? if you go outside on a clear , dark , moonless night — and you really should — chances are pretty good that within a few minutes you ’ ll see a shooting star . it ’ ll zip across the sky , a fiery dot leaving a long glowing trail behind it . they ’ re one of the most exciting and fun things you ’ ll see when you look up , and they always get a gasp and a squeal of delight from people someone who ’ s stargazing . what you ’ re actually seeing is a tiny bit of interplanetary debris : rock , ice , or metal ramming through the earth ’ s atmosphere , heated to incandescence . most are faint , but some can be astonishingly bright ; i saw one once that left an afterimage on my eye ! obviously , shooting stars aren ’ t really stars . so what do we call them ? sometimes it seems like astronomers use different names for objects to keep things as confusing as possible . but really , we do that to separate out different things . in this case , the actual bit of solid stuff coming from space is called a meteoroid . the phenomenon of the meteoroid getting hot and blazing across the sky is called a meteor . and finally , if it hits the ground , we call it a meteorite . i think the second best way to tick off an astronomer is to mix up meteor and meteorite . sometimes astronomers can be pretty pedantic about such things . oh , the best way to tick off an astronomer ? ask them , “ hey , what ’ s your sign ? ” amazingly , a typical meteor that you ’ ll see is due to a meteoroid that ’ s tiny , probably smaller than a grain of sand ! how can that be ? it ’ s because they ’ re hauling mass . you heard me . the meteoroid is orbiting the sun , probably at speeds of a few dozen kilometers per second . as it approaches the earth , our planet ’ s gravity accelerates it an additional 11 kilometers per second — earth ’ s escape velocity . and when it enters our atmosphere it ’ s moving incredibly fast , up to 70 km/sec or more . the energy of motion is called kinetic energy . if you want to get something moving , you have to give it energy , and if you want it to stop , you have to take that energy away . this kinetic energy depends on the mass of the object and how fast it ’ s moving . in fact , it depends on the square of the velocity ; double its speed and it ’ ll have four times the kinetic energy . meteoroids may usually be small , but they ’ re screaming fast , and have a huge amount of kinetic energy . as they hit our atmosphere they slow from their ridiculous orbital speed to nearly a standstill , and all that energy has to go somewhere . it gets converted into light and heat , and that ’ s what we see as a meteor . a big misconception about meteors is that they get hot due to friction with air . actually , a far bigger contributor to their heat is compression . one of the most basic laws of physics is that when you compress a gas it heats up . and a meteoroid coming in at hypersonic speeds compresses the air in front of it a lot , heating it hugely . the gas can reach temperatures of thousands of degrees celsius for a few seconds . the air radiates away this heat , in turn heating up the meteoroid . the material on the surface vaporizes and blows away—a process called ablation . that ablated material leaves a glowing trail behind the meteor , which we call a train . sometimes it can glow for several minutes , getting twisted up in high altitude winds , leaving behind an eerie , ghost-like persistent train . this all happens high above your head , about 90 – 100 km above the ground . typically , from any one location , you can see a few meteors per hour . it may not seem like much , but when you add them up all over the planet you find the earth is getting pelted to the tune of about 100 tons of material a day . but again , most of these meteoroids are teeny tiny . those random meteors are called sporadic meteors . they tend to be rocky in composition , and generally come from asteroids . if two asteroids smack into each other , the collision can eject little bits of material that then orbit the sun on their own . if their orbit crosses the earth , then you have a potential meteor . it may take a few million years , but at some point the earth and the meteoroid are at the same place at the same time , and boom . but sometimes meteoroids travel in packs . when that happens , we can get meteor showers , many dozens or even hundreds of meteors per hour . with one exception , those don ’ t come from asteroids : they come from comets . when a comet orbits the sun , the ice on it turns to gas , dislodging dust and gravel mixed in . this material leaves the comet and tends to stay more or less in the same orbit as the comet itself . over time , that material gets scattered all along the orbit , creating a puffy ribbon of tiny pieces of space debris around the sun . when the earth plows through that cloud of debris , we get a meteor shower . from our viewpoint on earth we see meteors shooting across the sky , apparently radiating away from a single point . that ’ s a perspective effect ; it ’ s like driving through a tunnel and seeing the tiles on the wall and ceiling flying past you , all apparently coming from a point ahead of you . the point in the sky where the meteors come from is called the radiant , and the shower is named after the constellation the radiant ’ s in . so we have the perseid meteor shower , the leonids , the camelopardalids . or the camelopardalids . and , since the earth hits a specific comet stream around the same time every year , the showers are annual . the perseids are in august , and the leonids in november . watching a meteor shower is easy : just go outside and look up ! generally , they ’ re better after local midnight . the earth plows into the meteoroids , so facing the direction of earth ’ s orbital motion means more meteors , just like you get more raindrops on the front windshield of your car than than on the back when driving through a storm . after local midnight you ’ re on the part of the earth facing into the orbit , so you see more meteors . by the way , if you happen to be on the international space station , you have to look down to see a meteor . in 2011 , astronaut ron garan photographed a perseid burning up below him ! but don ’ t worry : the odds of the space station getting hit are extremely low . space is big . oh , and that one exception i mentioned before ? that ’ s the annual geminids shower , which occurs in december . that comes from the asteroid 3200 phaethon , which is on an orbit that takes it very close to the sun . it ’ s possible it gets so hot that the rock vaporizes , making it act like a comet . the vast majority of meteoroids are small and tend to burn up in our atmosphere . but they can be bigger . a bolide , or fireball , is an extremely bright meteor , and those can be about the size of a grapefruit . those happen pretty often somewhere over the earth . i ’ ve seen a few myself . very rarely , an incoming meteoroid will survive all the way to the ground and become a meteorite . sometimes , the immense pressure of ramming earth ’ s air causes the incoming meteoroid to crumble or even explode , raining down dozens or hundreds of smaller pieces . typically , they slow rapidly after their blaze of glory , and simply fall the rest of the way to the ground . the air up there is cold , and their interiors are cold from being in space so long . so , despite what you might think , meteorites don ’ t cause fires when they hit the ground . in fact , they can be quite chilly ! meteorites are classified into three broad categories : stony , which are mostly rock ; iron , which are mostly metal ; and stony iron , which are a mixture of the two . the majority of meteorites we find are stony . the stony meteorites are subdivided into two kinds : chondrites , and achondrites . chondrites contain chondrules , small grains of minerals . these are very primitive , and are thought to have condensed out of the original disk of material that formed the solar system . their age can be found by looking at ratios of elements in them formed from radioactive decay . the oldest known meteorite formed 4.568 billion years ago : before the earth itself formed ! achondrites don ’ t have chondrules in them . most likely they came from a bigger asteroid , one that was once molten through , mixing the minerals . a big collision disrupted the parent body , creating the achondritic meteoroids . iron meteorites most likely come from the center of a large asteroid , one big enough that metals fell to the center via gravity . again , a big impact blew the asteroid up , scattering its material around the asteroid belt , and with some on orbits that eventually intersected earth . stony irons are the rarest . some have green or orange crystals of a mineral called olivine embedded in a web of metal . called pallasites , they may be the most beautiful of all meteorites . i actually collect meteorites . it ’ s fun but can be a somewhat pricey hobby . if you ’ re interested , make sure you get ‘ em from a licensed dealer . we have links to some in the dooblydoo . of course , on occasion the meteoroid coming in can be a tad bigger . and when that happens , well , all hell can break loose . on february 15 , 2013 , residents of the russian city of chelyabinsk got a rude awakening . at 9:20 a.m. local time , a rock about 19 meters across came in at a low angle . it got nearly as bright as the sun as it slammed into the atmosphere , and the pressure of its passage broke it up into several chunks , which broke up again . in a moment ’ s time , the sudden energy released was equivalent to the detonation of a half million tons of tnt — as much as a small atomic bomb ! while no one was killed , over a thousand people were injured by flying glass , shattered by the explosion . no doubt they were at their windows gawking at the huge vapor trail in the sky when the shock wave hit . there was no warning for this event ; the asteroid was essentially too small to detect while it was out in space . well , for now at least . telescopes are coming online soon that should be able to find smaller asteroids and give us some warning . astronomers are more worried about ones roughly a hundred meters across or bigger ; these can do serious damage on a city-wide scale or larger , but at the moment aren ’ t easy to spot much in advance . and what do we do if we do see one headed our way ? as of right now , there ’ s not much we can do . studies have been done to determine the best course of action ; maybe lobbing a nuke at it , or simply ramming it with a spaceprobe to change the orbit and make sure it misses earth . these ideas look good on paper , but they haven ’ t been tested yet . we ’ re still a few years from that . the good news is that objects that size hitting the earth are rare ; maybe once every century or three . but if we do nothing , it will happen eventually . as science fiction writer larry niven points out , the dinosaurs went extinct because they didn ’ t have a space program . hopefully , we ’ re smarter than they were . today you learned that meteors are small bits of interplanetary debris sloughed off by asteroids and comets . when the earth plows through the stream emitted by a comet we get a meteor shower . meteors burn up about 100 km above the earth , but some survive to hit the ground . most of these meteorites are rocky , some are metallic , and a few are a mix of the two . very big meteorites can be a very big problem , but there are plans in the works to prevent us from going the way of the dinosaurs . crash course astronomy - hey crash course , meteors ! cool ! crash course astronomy is produced in association with pbs digital studios . head over to their channel for even more awesome videos . this episode was written by me , phil plait . the script was edited by blake de pastino , and our consultant is dr. michelle thaller . it was directed by nicholas jenkins , the script supervisor and editor is nicole sweeney , the sound designer was michael aranda , and the graphics team is thought café .
|
in this case , the actual bit of solid stuff coming from space is called a meteoroid . the phenomenon of the meteoroid getting hot and blazing across the sky is called a meteor . and finally , if it hits the ground , we call it a meteorite .
|
the phenomenon of solid matter getting hot and blazing brightly across the sky is called a ...
|
translator : andrea mcdonough reviewer : bedirhan cinar a couple of years ago i started using twitter , and one of the things that really charmed me about twitter is that people would wake up in the morning and they would say , `` good morning ! '' which i thought , i 'm a canadian , so i was a little bit , i liked that politeness . and so , i 'm also a giant nerd , and so i wrote a computer program that would record 24 hours of everybody on twitter saying , `` good morning ! '' and then i asked myself my favorite question , `` what would that look like ? '' well , as it turns out , i think it would look something like this . right , so we 'd see this wave of people saying , `` good morning ! '' across the world as they wake up . now the green people , these are people that wake up at around 8 o'clock in the morning , who wakes up at 8 o'clock or says , `` good morning ! '' at 8 ? and the orange people , they say , `` good morning ! '' around 9 . and the red people , they say , `` good morning ! '' around 10 . yeah , more at 10 's than , more at 10 's than 8 's . and actually if you look at this map , we can learn a little bit about how people wake up in different parts of the world . people on the west coast , for example , they wake up a little bit later than those people on the east coast . but that 's not all that people say on twitter , right ? we also get these really important tweets , like , `` i just landed in orlando ! ! [ plane sign , plane sign ] '' or , or , `` i just landed in texas [ exclamation point ] ! '' or `` i just landed in honduras ! '' these lists , they go on and on and on , all these people , right ? so , on the outside , these people are just telling us something about how they 're traveling . but we know the truth , do n't we ? these people are show-offs ! they are showing off that they 're in cape town and i 'm not . so i thought , how can we take this vanity and turn it into utility ? so using a similar approach that i did with `` good morning , '' i mapped all those people 's trips because i know where they 're landing , they just told me , and i know where they live because they share that information on their twitter profile . so what i 'm able to do with 36 hours of twitter is create a model of how people are traveling around the world during that 36 hours . and this is kind of a prototype because i think if we listen to everybody on twitter and facebook and the rest of our social media , we 'd actually get a pretty clear picture of how people are traveling from one place to the other , which is actually turns out to be a very useful thing for scientists , particularly those who are studying how disease is spread . so , i work upstairs in the new york times , and for the last two years , we 've been working on a project called , `` cascade , '' which in some ways is kind of similar to this one . but instead of modeling how people move , we 're modeling how people talk . we 're looking at what does a discussion look like . well , here 's an example . this is a discussion around an article called , `` the island where people forget to die '' . it 's about an island in greece where people live a really , really , really , really , really , really long time . and what we 're seeing here is we 're seeing a conversation that 's stemming from that first tweet down in the bottom , left-hand corner . so we get to see the scope of this conversation over about 9 hours right now , we 're going to creep up to 12 hours here in a second . but , we can also see what that conversation looks like in three dimensions . and that three-dimensional view is actually much more useful for us . as humans , we are really used to things that are structured as three dimensions . so , we can look at those little off-shoots of conversation , we can find out what exactly happened . and this is an interactive , exploratory tool so we can go through every step in the conversation . we can look at who the people were , what they said , how old they are , where they live , who follows them , and so on , and so on , and so on . so , the times creates about 6,500 pieces of content every month , and we can model every single one of the conversations that happen around them . and they look somewhat different . depending on the story and depending on how fast people are talking about it and how far the conversation spreads , these structures , which i call these conversational architectures , end up looking different . so , these projects that i 've shown you , i think they all involve the same thing : we can take small pieces of data and by putting them together , we can generate more value , we can do more exciting things with them . but so far we 've only talked about twitter , right ? and twitter is n't all the data . we learned a moment ago that there is tons and tons , tons more data out there . and specifically , i want you to think about one type of data because all of you guys , everybody in this audience , we , we , me as well , are data-making machines . we are producing data all the time . every single one of us , we 're producing data . somebody else , though , is storing that data . usually we put our trust into companies to store that data , but what i want to suggest here is that rather than putting our trust in companies to store that data , we should put the trust in ourselves because we actually own that data . right , that is something we should remember . everything that someone else measures about you , you actually own . so , it 's my hope , maybe because i 'm a canadian , that all of us can come together with this really valuable data that we 've been storing , and we can collectively launch that data toward some of the world 's most difficulty problems because big data can solve big problems , but i think it can do it the best if it 's all of us who are in control . thank you .
|
well , as it turns out , i think it would look something like this . right , so we 'd see this wave of people saying , `` good morning ! '' across the world as they wake up .
|
according to thorp 's map of people saying good morning , who sleeps until later in the day ?
|
the onset of cancer usually begins as a solitary tumor in a specific area of the body . if the tumor is not removed , cancer has the ability to spread to nearby organs , as well as places far away from the origin , such as the brain . so how does cancer move to new areas , and why are some organs more likely to get infected than others ? the process of cancer spreading across the body is known as metastasis . it begins when cancer cells from an initial tumor invade nearby normal tissue . as the cells proliferate , they spread via one of the three common routes of metastasis : transcoelomic , lymphatic , or hematogenous spread . in transcoelomic spread , malignant cells penetrate the covering surfaces of cavities in our body . these surfaces are known as peritoneum and serve as walls to segment the body cavity . malignant cells in ovarian cancer , for example , spread through peritoneum , which connects the ovary to the liver , resulting in metastasis on the liver surface . next , cancerous cells invade blood vessels when they undergo hematogenous spread . as there are blood vessels almost everywhere in the body , malignant cells utilize this to reach more distant parts of the body . finally , lymphatic spread occurs when the cancer invades the lymph nodes , and travels to other parts of the body via the lymphatic system . as this system drains many parts of the body , it also provides a large network for the cancer . in addition , the lymphatic vessels empty into the blood circulation , allowing the malignant cells to undergo hematogenous spread . once at a new site , the cells once again undergo proliferation , and form small tumors known as micrometastases . these small tumors then grow into full-fledged tumors , and complete the metastatic process . different cancers have been known to have specific sites of metastasis . for example , prostate cancer commonly metastasizes to the bone , while colon cancer metastasizes to the liver . various theories have been proposed to explain the migration pattern of malignant cells . of particular interest are two conflicting theories . stephen paget , an english surgeon , came up with the seed and soil theory of metastasis . the seed and soil theory stated that cancer cells die easily in the wrong microenvironment , hence they only metastasize to a location with similar characteristics . however , james ewing , the first professor of pathology at cornell university , challenged the seed and soil theory , and proposed that the site of metastasis was determined by the location of the vascular and lymphatic channels which drain the primary tumor . patients with primary tumors that were drained by vessels leading to the lung would eventually develop lung metastases . today , we know that both theories contain valuable truths . yet the full stories of metastasis is much more complicated than either of the two proposed theories . factors like the cancer cell 's properties , and the effectiveness of the immune system in eliminating the cancer cells , also play a role in determining the success of metastasis . unfortunately , many questions about metastasis remain unanswered until today . understanding the exact mechanism holds an important key to finding a cure for advanced stage cancers . by studying both the genetic and environmental factors , which contribute to successful metastasis , we can pinpoint ways to shut down the process . the war against cancer is a constant struggle , and scientists are hard at work developing new methods against metastasis . of recent interest is immunotherapy , a modality which involves harnessing the power of the immune system to destroy the migrating cells . this can be done in different ways , such as training immune cells to recognize cancerous cells via vaccines . the growth and activity of the immune cells can also be stimulated by injecting man-made interleukins , chemicals which are usually secreted by the immune cells of the body . these two treatments are only the tip of the iceberg . with the collaborated research efforts of governments , companies and scientists , perhaps the process of metastasis will be stopped for good .
|
once at a new site , the cells once again undergo proliferation , and form small tumors known as micrometastases . these small tumors then grow into full-fledged tumors , and complete the metastatic process . different cancers have been known to have specific sites of metastasis . for example , prostate cancer commonly metastasizes to the bone , while colon cancer metastasizes to the liver .
|
what are some other ways that we can use to treat metastatic cancers ?
|
translator : andrea mcdonough reviewer : bedirhan cinar you 've probably heard of pavlov 's dogs , the phrase that often summarizes dr. ivan pavlov 's early 20th century research , in which he demonstrated that we can alter what stimuli elicit a reflective response in canines . he showed this by sounding a bell just before he presented his group of dogs with meat powder . after many presentations of the bell , followed by tasty meat powder , the dogs eventually began to salivate at just the sound of the bell . they salivated even when there was no meat powder present . this phenomenon is n't limited to dogs . consider the placebo effect , in which a pill with no active substances brings about a response similar to a pill with a substance present . what changes here is our reaction to our ailment , such as perceiving less pain and not the ailment itself . or , consider the love humans have for a parent . some would argue that this love is instinctual , and they may be partially right . but , the argument fails to account for the equal amount of love that children adopted later in life hold for their adoptive parents . but the behaviorist argument can account for both accounts of love . a parent , biological or not , is constantly paired with things like food , smiles , toys , affection , games , protection , and entertainment . and a parent 's constant association with these wonderful or crucial aspects of a child 's life has a similar , albeit more complicated , effect that meat powder had on pavlov 's salivating dogs . in other words , if one 's parent is predictive of really good or really important things , then one 's parent becomes a really good and important thing , too . and there is also romantic advice to be gained from pavlov 's observations . we all need food to survive , right ? and someone who can provide such things in a delicious , saliva-producing manner stands to become our human equivalent of a ringing bell . in other words , if you can cook one or more scrumptious meals for a potential love interest , there 's a good chance that you 'll be viewed more favorably in the future , even if you did n't prepare the delicious food . and who would n't want the love of their life drooling over them ? but life is not just bell rings and salivation . there 's also a dark side to this type of learning , called `` taste aversion '' . taste aversion occurs when we ingest some food that eventually makes us sick , and , as a result , we avoid that food , sometimes for the rest of our lives . taste aversion is so powerful that the effect can be seen even if the illness is experienced hours later and even if the food itself did not actually make us sick . such is the case when we have the flu , and , by accident , we ingest some food moments prior to vomiting . in this case , we know that the food did not cause the vomiting , but our bodies do n't know that . and the next time we encounter that food , we are likely to refuse eating it . now , imagine the potential consequences of undercooking a meal on a first date . if the food makes your date sick , it is possible for them to associate that bad feeling with not just the food , but with < i > your < /i > food in particular . if the episode was traumatizing enough , or if it also happens on a subsequent date , they may come to relate you with the consequences , just like pavlov 's dogs related the bell with the meat powder . in other words , the sight of you showing up at the next dinner date might actually make your date nauseous ! as the old saying goes , the fastest way to someone 's heart is through their stomach , assuming you do n't make them sick in the process .
|
and a parent 's constant association with these wonderful or crucial aspects of a child 's life has a similar , albeit more complicated , effect that meat powder had on pavlov 's salivating dogs . in other words , if one 's parent is predictive of really good or really important things , then one 's parent becomes a really good and important thing , too . and there is also romantic advice to be gained from pavlov 's observations .
|
when someone is on a first date , it is a good idea to do something exciting ( like ride a rollercoaster ) and have a really nice meal together . why do you think the date should occur in that order ( rollercoaster then dinner ) ? also , in relation to reflexive responses , why would the rollercoaster experience be a good idea ? ( hint : think about the response to each event and why you want to be paired with that . )
|
we all know that there are certain virtues that are good for us . intelligence , wisdom , bravery , justice , respect , responsibility , honesty , unselfishness , compassion , patience , and perseverance always have been and always will be positive virtues . think of some people who have those traits . maybe it 's martin luther king or abraham lincoln or george washington . i bet you know a lot of facts about these historical figures , but maybe you 've never taken the time to think about their character . let 's talk about sybil ludington . she 's a little-known revolutionary figure , but boy , was she something ! she rode 40 miles through the damp , cold night of april 26 , 1777 to alert the colonial militia of a british attack . her action was similar to that of paul revere , only she rode twice as far and was only 16 years old . that takes some real guts ! beriah green ? anyone ever heard of beriah green ? he was president of the first integrated school in the united states . he also spent the majority of his life fighting for the immediate abolition of slavery . he used his voice , pen , and good deed to fight slavery . beriah green was fiercely devoted to abolition before it was popular because he believed it was the right thing to do . and then there 's abraham lincoln . you know he was president during the civil war . he wrote the emancipation proclaimation and is credited with freeing the slaves . he went to war with the south to save the union . he helped the country get through one of its most difficult times . he kept the united states united . but , above all that , abraham lincoln showed great leadership . could any of these people have done the deeds they 're famous for without bravery , compassion , dedication , or wisdom ? no ! history can teach us much more than just the facts . it 's full of examples of how to live better . and for you , even if you 're not freeing the slaves or riding 40 miles on horseback , bravery and wisdom will help you get an a on that test , ask out that cute boy , and get that great job .
|
she 's a little-known revolutionary figure , but boy , was she something ! she rode 40 miles through the damp , cold night of april 26 , 1777 to alert the colonial militia of a british attack . her action was similar to that of paul revere , only she rode twice as far and was only 16 years old .
|
what virtue did sybil ludington demonstrate when she rode 40 miles through the damp , cold night of april 1777 ?
|
in 2011 , a team of physicists reported a startling discovery : neutrinos traveled faster than the speed of light by 60 billionths of a second in their 730 kilometer trip from geneva to a detector in italy . despite six months of double checking , the bizarre discovery refused to yield . but rather than celebrating a physics revolution , the researchers published a cautious paper arguing for continued research in an effort to explain the observed anomaly . in time , the error was tracked to a single incorrectly connected fiber optic cable . this example reminds us that real science is more than static textbooks . instead , researchers around the world are continuously publishing their latest discoveries with each paper adding to the scientific conversation . published studies can motivate future research , inspire new products , and inform government policy . so it 's important that we have confidence in the published results . if their conclusions are wrong , we risk time , resources , and even our health in the pursuit of false leads . when findings are significant , they are frequently double-checked by other researchers , either by reanalyzing the data or by redoing the entire experiment . for example , it took repeated investigation of the cern data before the timing error was tracked down . unfortunately , there are currently neither the resources nor professional incentives to double check the more than 1 million scientific papers published annually . even when papers are challenged , the results are not reassuring . recent studies that examined dozens of published pharmaceutical papers managed to replicate the results of less than 25 % of them . and similar results have been found in other scientific disciplines . there are a variety of sources for irreproducible results . errors could hide in their original design , execution , or analysis of the data . unknown factors , such as patients ' undisclosed condition in a medical study , can produce results that are not repeatable in new test subjects . and sometimes , the second research group ca n't reproduce the original results simply because they do n't know exactly what the original group did . however , some problems might stem from systematic decisions in how we do science . researchers , the institutions that employ them , and the scientific journals that publish findings are expected to produce big results frequently . important papers can advance careers , generate media interest , and secure essential funding , so there 's slim motivation for researchers to challenge their own exciting results . in addition , little incentive exists to publish results unsupportive of the expected hypothesis . that results in a deluge of agreement between what was expected and what was found . in rare occasions , this can even lead to deliberate fabrication , such as in 2013 , when a researcher spiked rabbit blood with human blood to give false evidence that his hiv vaccine was working . the publish or perish mindset can also compromise academic journals ' traditional peer-review processes which are safety checks where experts examine submitted papers for potential shortcomings . the current system , which might involve only one or two reviewers , can be woefully ineffective . that was demonstrated in a 1998 study where eight weaknesses were deliberately inserted into papers , but only around 25 % were caught upon review . many scientists are working toward improving reproducibility in their fields . there 's a push to make researchers raw data , experimental procedures , and analytical techniques more openly available in order to ease replication efforts . the peer review process can also be strengthened to more efficiently weed out weak papers prior to publication . and we could temper the pressure to find big results by publishing more papers that fail to confirm the original hypothesis , an event that happens far more than current scientific literature suggests . science always has , and always will , encounter some false starts as part of the collective acquisition of new knowledge . finding ways to improve the reproducibility of our results can help us weed out those false starts more effectively , keeping us moving steadily toward exciting new discoveries .
|
in rare occasions , this can even lead to deliberate fabrication , such as in 2013 , when a researcher spiked rabbit blood with human blood to give false evidence that his hiv vaccine was working . the publish or perish mindset can also compromise academic journals ' traditional peer-review processes which are safety checks where experts examine submitted papers for potential shortcomings . the current system , which might involve only one or two reviewers , can be woefully ineffective .
|
which of the following is not at least a partial potential remedy for irreproducibility ?
|
translator : andrea mcdonough reviewer : jessica ruby there are all sorts of things that happen every day that might make you ask , `` why ? why do we drive on a parkway and park on a driveway ? why does my hair get frizzy when it 's humid ? and why do my fingers get all pruney when they 're wet ? '' often we simply ca n't know the answers to these questions . but progress can often be made , and , when it comes to your pruney fingers , scientists have a few interesting ideas . the story here begins with an observation made in the 1930s in the emergency room . doctors noticed that patients with nerve damage to their hands did not get pruney fingertips like most of us do in a bath , which might make you wonder , `` why would primates want wrinkly fingers , presumably when it 's rainy or dewy ? '' what could this trait be for ? what if these wrinkles functioned like rain treads ? think about car tires . when the ground is dry , it 's generally best to have smooth tires , and race cars do . smooth tires means more rubber or surface area in contact with the road , which gives them better grip . but in rainy and muddy conditions , it 's a different story , and here 's where treads come into play . treads reduce the amount of rubber on the road , but they help channel out water when it rains , lowering the risk of hydroplaning . well , if your fingers really are like rain treads , you should be able to predict the optimal shape for them , right ? so , what would the predicted wrinkle shapes be ? that is , are our prunes actually the right shape to be rain treads ? let 's take a detour into rivers . when we think of river networks , we usually imagine lots of smaller river channels joining to make larger river channels downstream , which is what happens in concave basins . in these cases , the divides , the regions between the river segments , are disconnected from one another and diverge away from one another uphill . but river networks look fundamentally different on convex promontories or protrusions . here , the river channels are disconnected from one another and diverge away from one another downstream , not very river-like . in these cases , it 's the divides that link together to form a tree , with its trunk uphill at the top of the promontory . here , it 's the divides that look more traditionally river-like . if our pruney fingers are drainage networks , designed to channel out water when they grip , then we expect to find similar shapes on our fingers as we find out there among rivers . there should be a tree network of divides , or ridges , with their trunk near the top of the fingertip and with their more leaky parts reaching out downhill , away from the tip . the channels themselves , through which the water is channeled during a grip , should not connect to one another , and instead should diverge away from one another downhill . if pruney fingers are rain treads , then they should look like the river networks on convex promontories . in fact , that 's exactly the morphology we find among pruney fingers ! when we grip , then , our pruney wrinkles really do channel out the water . but does it actually help us grip ? new behavioral experiments have shown that they do . in a task where subjects had to grasp wet marbles and move them through a hole and out the other side , those with pruney fingers finished the task significantly faster than those with smooth fingers . pruney fingers not only ought to enhance grip in wet conditions but do . so , pruney fingers may be a crucial part of the primate repertoire . maybe , once primates lost their claws in favor of fingernails , rain treads were needed to deal with the especially challenging , often wet , grip-heavy forest habitats . by looking closely at the mysteries in our world and trying to find things that look similar , like our wet fingers and rain treads , we can come up with ideas about what 's happening . and that 's a good way to think about all sorts of questions in life , too .
|
why does my hair get frizzy when it 's humid ? and why do my fingers get all pruney when they 're wet ? '' often we simply ca n't know the answers to these questions .
|
what evidence is there that the pruney response is neuronally modulated ?
|
so potassium metal is very reactive . one of my colleagues who used to work with it , described it as evil . so we 've come out behind the chemistry department . in the open air . to try and do a re-take of the potassium video . the last sample of potassium was very very small , maybe 500mg . it will react , it is so reactive that if you have it in a box with argon , so that it ca n't get oxygen from anywhere , it will take the oxygen out of paper . which is , paper is a compound of carbon , hydrogen and oxygen . and it can extract this . it 's a reactive element . it 's used in our body all the time . we have like , lots of potassium floating around . and we 've got some samples here , about a gram , maybe a gram and a half of each . it 's a pretty big chunk of potassium this . ready ? yeah . very satisfying reaction . after completing the 100 meters dash ... like sodium it'ss quite a low melting point metal . and if you mix sodium and potassium together , to make so called sodium potassium amalgam , it 's called nak , by those who work in the trade , na for sodium , k for potassium . nak is a liquid at room temperature . it looks a bit like mercury . a silver liquid . it 's very light . and i never played with it , but people say that if you try and drop it on the floor , it will burst into flames before it hits the floor , because it reacts with the water in the air . today i 'm going to show you how to make a potassium mirror . we will just fish out a nice little bit of potassium . it 's stored under mineral oil , because it reacts with water over time . so it 's quite malleable stuff . it 's a little bit like if you imagine cutting blu tac . it 's quite soft . and it starts you see , it 's starting to go a little bit already . tarnishing a wee bit . so we can just manipulate it like that , and we are gon na pop it into our ampule , and we are gon na evacuate it now . i 'm gon na remove all of the atmosphere , from this ampule . ok , we 've done that because the , the boiling point of potassium under one atmosphere is over 700 degrees c. which is pretty high . it 's too high for the glass to tolerate . if i heated it up to that temperature the glass would start to soften , melt . so by evacuating it , we remove all of the atmosphere which is keeping the boiling point as high as it is . so it lowers the boiling point much lower . so it starts to drop into the range of water . ok so we are just going to the blue flame , which is the nice hot flame . and we just keep on gently warming it . and at some point , it will melt . just enough that you will start to see bubbles of potassium just jumping out of this thin oxide layer , which is coating it at the minute . now it 's starting to form . so the reason we do it like this is that we end up with a large surface of potassium , so it 's excellent for keeping our solvents dry . so what we 've got now , is we 've got the ampule , and all the way up here , this is literally a mirror of very thin potassium . potassium is very important . our bodies contain quite a lot of potassium . and it 's in all sorts of biological material . if you burn garden rubbish , in the ash that you get in the end is potassium , which is presumably why it 's called potash . so as neil quite literally wets the wall , to get rid of all the un-reacted potassium . wicked . one of my colleagues who used to work with it , described it as evil . captions by www.subply.com
|
and it 's in all sorts of biological material . if you burn garden rubbish , in the ash that you get in the end is potassium , which is presumably why it 's called potash . so as neil quite literally wets the wall , to get rid of all the un-reacted potassium .
|
what does the professor give as the possible reason for the fact that we call burned garden rubbish “ potash ” ?
|
in this dystopian world , your resistance group is humanity 's last hope . unfortunately , you 've all been captured by the tyrannical rulers and brought to the ancient colosseum for their deadly entertainment . before you 're thrown into the dungeon , you see many numbered hallways leading outside . but each exit is blocked by an electric barrier with a combination keypad . you learn that one of you will be allowed to try to escape by passing a challenge while everyone else will be fed to the mutant salamanders the next morning . with her perfect logical reasoning , zara is the obvious choice . you hand her a concealed audio transmitter so that the rest of you can listen along . as zara is led away , you hear her footsteps echo through one of the hallways , then stop . a voice announces that she must enter a code consisting of three positive whole numbers in ascending order , so the second number is greater than or equal to the first , and the third is greater than or equal to the second . she may ask for up to three clues , but if she makes a wrong guess , or says anything else , she 'll be thrown back into the dungeon . for the first clue , the voice says the product of the three numbers is 36 . when zara asks for the second clue , it tells her the sum of the numbers is the same as the number of the hallway she entered . there 's a long silence . you 're sure zara remembers the hallway number , but there 's no way for you to know it , and she ca n't say it outloud . if zara could enter the passcode at this point , she would , but instead , she asks for the third clue , and the voice announces that the largest number appears only once in the combination . moments later , the buzz of the electric barrier stops for a few seconds , and you realize that zara has escaped . unfortunately , her transmitter is no longer in range , so that 's all the information you get . can you find the solution ? pause on the next screen to work out the solution . 3 2 1 you 're worried about the fact that you do n't know zara 's hallway number , but you decide to start from the beginning anyways . from the first clue , you work out all of the eight possible combinations that come out to a product of 36 . one of these must be right , but which one ? now comes the hard part . even though you do n't know which number you 're looking for , you decide to work out the sum of each combination 's three numbers . that 's when it hits you . all but two of the sums are unique , and if the hallway number had matched any of these , zara would have known the correct combination right then and there without asking for the third clue . since she did ask for the clue , the hallway number must have matched the only sum that appears more than once in the list : thirteen . but which of the two combinations that add up to thirteen is correct : 1,6,6 , or 2,2,9 ? that 's where the third clue comes in . since it tells us that the largest number must be unique , 2,2,9 must be the code . when night falls , you and the others escape through hallway thirteen and rejoin zara outside . you 've freed yourselves through math and logic . now it 's time to free the rest of the world .
|
but which of the two combinations that add up to thirteen is correct : 1,6,6 , or 2,2,9 ? that 's where the third clue comes in . since it tells us that the largest number must be unique , 2,2,9 must be the code .
|
why did zara need the third clue ?
|
so molybdenum is an element which is essential to life and most organisms beginning with you and me and going down to bacteria have enzymes that contain molybdenum . one of the most important enzymes is so called nitrogenase which is an enzyme that will turn nitrogen into ammonia , and nitrogenase is found in various bacteria that live in the roots of plants like beans . so the beans , via these bacteria , can absorb nitrogen into the atmosphere and turn it into a form that we can digest and we need that nitrogen so that we can make the proteins in our body . so without molybdenum nothing could live .
|
so the beans , via these bacteria , can absorb nitrogen into the atmosphere and turn it into a form that we can digest and we need that nitrogen so that we can make the proteins in our body . so without molybdenum nothing could live .
|
where in your body can you find molybdenum ?
|
the sun is shining . the birds are singing . it looks like the start of another lovely day . you 're walking happily in the park , when , `` ah-choo ! '' a passing stranger has expelled mucus and saliva from their mouth and nose . you can feel the droplets of moisture land on your skin , but what you ca n't feel are the thousands , or even millions , of microscopic germs that have covertly traveled through the air and onto your clothing , hands and face . as gross as this scenario sounds , it 's actually very common for our bodies to be exposed to disease-causing germs , and most of the time , it 's not nearly as obvious . germs are found on almost every surface we come into contact with . when we talk about germs , we 're actually referring to many different kinds of microscopic organisms , including bacteria , fungi , protozoa and viruses . but what our germs all have in common is the ability to interact with our bodies and change how we feel and function . scientists who study infectious diseases have wondered for decades why it is that some of these germs are relatively harmless , while others cause devastating effects and can sometimes be fatal . we still have n't solved the entire puzzle , but what we do know is that the harmfulness , or virulence , of a germ is a result of evolution . how can it be that the same evolutionary process can produce germs that cause very different levels of harm ? the answer starts to become clear if we think about a germ 's mode of transmission , which is the strategy it uses to get from one host to the next . a common mode of transmission occurs through the air , like the sneeze you just witnessed , and one germ that uses this method is the rhinovirus , which replicates in our upper airways , and is responsible for up to half of all common colds . now , imagine that after the sneeze , one of three hypothetical varieties of rhinovirus , let 's call them `` too much , '' `` too little , '' and `` just right , '' has been lucky enough to land on you . these viruses are hardwired to replicate , but because of genetic differences , they will do so at different rates . `` too much '' multiplies very often , making it very successful in the short run . however , this success comes at a cost to you , the host . a quickly replicating virus can cause more damage to your body , making cold symptoms more severe . if you 're too sick to leave your home , you do n't give the virus any opportunities to jump to a new host . and if the disease should kill you , the virus ' own life cycle will end along with yours . `` too little , '' on the other hand , multiplies rarely and causes you little harm in the process . although this leaves you healthy enough to interact with other potential hosts , the lack of symptoms means you may not sneeze at all , or if you do , there may be too few viruses in your mucus to infect anyone else . meanwhile , `` just right '' has been replicating quickly enough to ensure that you 're carrying sufficient amounts of the virus to spread but not so often that you 're too sick to get out of bed . and in the end , it 's the one that will be most successful at transmitting itself to new hosts and giving rise to the next generation . this describes what scientists call trade-off hypothesis . first developed in the early 1980s , it predicts that germs will evolve to maximize their overall success by achieving a balance between replicating within a host , which causes virulence , and transmission to a new host . in the case of the rhinovirus , the hypothesis predicts that its evolution will favor less virulent forms because it relies on close contact to get to its next victim . for the rhinovirus , a mobile host is a good host , and indeed , that is what we see . while most people experience a runny nose , coughing and sneezing , the common cold is generally mild and only lasts about a week . it would be great if the story ended there , but germs use many other modes of transmission . for example , the malaria parasite , plasmodium , is transmitted by mosquitoes . unlike the rhinovirus , it does n't need us to be up and about , and may even benefit from harming us since a sick and immobile person is easier for mosquitoes to bite . we would expect germs that depend less on host mobility , like those transmitted by insects , water or food , to cause more severe symptoms . so , what can we do to reduce the harmfulness of infectious diseases ? evolutionary biologist dr. paul ewald has suggested that we can actually direct their evolution through simple disease-control methods . by mosquito-proofing houses , establishing clean water systems , or staying home when we get a cold , we can obstruct the transmission strategies of harmful germs while creating a greater dependence on host mobility . so , while traditional methods of trying to eradicate germs may only breed stronger ones in the long run , this innovative approach of encouraging them to evolve milder forms could be a win-win situation . ( cough ) well , for the most part .
|
unlike the rhinovirus , it does n't need us to be up and about , and may even benefit from harming us since a sick and immobile person is easier for mosquitoes to bite . we would expect germs that depend less on host mobility , like those transmitted by insects , water or food , to cause more severe symptoms . so , what can we do to reduce the harmfulness of infectious diseases ?
|
germs that depends less on host mobility :
|
in 1977 , the physicist edward purcell calculated that if you push a bacteria and then let go , it will stop in about a millionth of a second . in that time , it will have traveled less than the width of a single atom . the same holds true for a sperm and many other microbes . it all has to do with being really small . microscopic creatures inhabit a world alien to us , where making it through an inch of water is an incredible endeavor . but why does size matter so much for a swimmer ? what makes the world of a sperm so fundamentally different from that of a sperm whale ? to find out , we need to dive into the physics of fluids . here 's a way to think about it . imagine you are swimming in a pool . it 's you and a whole bunch of water molecules . water molecules outnumber you a thousand trillion trillion to one . so , pushing past them with your gigantic body is easy , but if you were really small , say you were about the size of a water molecule , all of a sudden , it 's like you 're swimming in a pool of people . rather than simply swishing by all the teeny , tiny molecules , now every single water molecule is like another person you have to push past to get anywhere . in 1883 , the physicist osborne reynolds figured out that there is one simple number that can predict how a fluid will behave . it 's called the reynolds number , and it depends on simple properties like the size of the swimmer , its speed , the density of the fluid , and the stickiness , or the viscosity , of the fluid . what this means is that creatures of very different sizes inhabit vastly different worlds . for example , because of its huge size , a sperm whale inhabits the large reynolds number world . if it flaps its tail once , it can coast ahead for an incredible distance . meanwhile , sperm live in a low reynolds number world . if a sperm were to stop flapping its tail , it would n't even coast past a single atom . to imagine what it would feel like to be a sperm , you need to bring yourself down to its reynolds number . picture yourself in a tub of molasses with your arms moving about as slow as the minute hand of a clock , and you 'd have a pretty good idea of what a sperm is up against . so , how do microbes manage to get anywhere ? well , many do n't bother swimming at all . they just let the food drift to them . this is somewhat like a lazy cow that waits for the grass under its mouth to grow back . but many microbes do swim , and this is where those incredible adaptations come in . one trick they can use is to deform the shape of their paddle . by cleverly flexing their paddle to create more drag on the power stroke than on the recovery stroke , single-celled organisms like paramecia manage to inch their way through the crowd of water molecules . but there 's an even more ingenious solution arrived at by bacteria and sperm . instead of wagging their paddles back and forth , they wind them like a cork screw . just as a cork screw on a wine bottle converts winding motion into forward motion , these tiny creatures spin their helical tails to push themselves forward in a world where water feels as thick as cork . other strategies are even stranger . some bacteria take batman 's approach . they use grappling hooks to pull themselves along . they can even use this grappling hook like a sling shot and fling themselves forward . others use chemical engineering . h. pylori lives only in the slimy , acidic mucus inside our stomachs . it releases a chemical that thins out the surrounding mucus , allowing it to glide through slime . maybe it 's no surprise that these guys are also responsible for stomach ulcers . so , when you look really closely at our bodies and the world around us , you can see all sorts of tiny creatures finding clever ways to get around in a sticky situation . without these adaptations , bacteria would never find their hosts , and sperms would never make it to their eggs , which means you would never get stomach ulcers , but you would also never be born in the first place . ( pop )
|
if it flaps its tail once , it can coast ahead for an incredible distance . meanwhile , sperm live in a low reynolds number world . if a sperm were to stop flapping its tail , it would n't even coast past a single atom .
|
which of the following changes has the largest effect on the swimming behavior ( reynolds number ) of a swimmer ?
|
in 19 b.c. , the roman poet virgil was traveling from greece to rome with the emperor augustus . on the way , he stopped to go sightseeing in megara , a town in greece . out in the sun for too long , he suffered heatstroke and died on his journey back to italy . on his deathbed , virgil thought about the manuscript he had been working on for over ten years , an epic poem that he called the `` aeneid . '' unsatisfied with the final edit , he asked his friends to burn it , but they refused , and soon after virgil 's death , augustus ordered it to be published . why was augustus so interested in saving virgil 's poem ? the romans had little tradition of writing serious literature and virgil wanted to create a poem to rival the `` iliad '' and `` odyssey '' of ancient greece . the `` aeneid , '' a 9,896 line poem , spans twelve separate sections , or books , the first six of which mirror the structure of the `` odyssey '' and the last six echo the `` iliad . '' also like the greek epics , the `` aeneid '' is written entirely in dactylic hexameter . in this meter , each line has six syllable groups called feet made up of dactyls which go long , short , short , and spondees which go long , long . so the famous opening line in the original latin starts , `` arma virvmqve cano , '' which can be translated as `` i sing of arms and the man , '' arms , meaning battles and warfare , another `` iliad '' reference , and the man being the hero aeneas . to understand the `` aeneid , '' it 's necessary to examine the unsettled nature of roman politics in the second half of the 1st century b.c . in 49 b.c. , julius caesar , augustus 's great uncle , triggered nearly 20 years of civil war when he led his army against the roman republic . after introducing a dictatorship , he was assassinated . only after augustus 's victory over marc antony and cleopatra in 31 b.c . did peace return to rome and augustus became the emperor . virgil aimed to capture this sense of a new era and of the great sacrifices that the romans had endured . he wanted to give the romans a fresh sense of their origins , their past , and their potential . by connecting the founding of rome to the mythological stories that his audience knew so well , virgil was able to link his hero aeneas to the character of augustus . in the epic poem , aeneas is on a quest to establish a new home for his people . this duty , or pietas as the romans called it , faces all kinds of obstacles . aeneas risks destruction in the ruins of troy , agonizes over love when he meets the beautiful queen of carthage , dido , and in one of the most vivid passages in all of ancient literature , has to pass through the underworld . on top of all that , he must then fight to win a homeland for his people around the future sight of rome . virgil presents aeneas as a sort of model for augustus , and that 's probably one of the reasons the emperor was so eager to save the poem from destruction . but virgil did n't stop there . in some sections , aeneas even has visions of rome 's future and of augustus himself . virgil presents augustus as a victor , entering rome in triumph and shows him expanding the roman empire . perhaps most importantly , he 's hailed as only the third roman leader in 700 years to shut the doors of the temple of janus signifying the arrival of permanent peace . but there 's a twist . virgil only read augustus three selected extracts of the story and that was augustus 's entire exposure to it . some of the other sections could be seen as critical , if not subtly subversive about the emperor 's achievements . aeneas , again a model for augustus , struggles with his duty and often seems a reluctant hero . he does n't always live up to the behavior expected of a good roman leader . he struggles to balance mercy and justice . by the end , the reader is left wondering about the future of rome and the new government of augustus . perhaps in wanting the story published , augustus had been fooled by his own desire for self-promotion . as a result , virgil 's story has survived to ask questions about the nature of power and authority ever since .
|
did peace return to rome and augustus became the emperor . virgil aimed to capture this sense of a new era and of the great sacrifices that the romans had endured . he wanted to give the romans a fresh sense of their origins , their past , and their potential . by connecting the founding of rome to the mythological stories that his audience knew so well , virgil was able to link his hero aeneas to the character of augustus .
|
how could an understanding of history help the romans develop a sense of their own identity ?
|
the story goes something like this : a royal , rich or righteous individual , who otherwise happens to be a lot like us , makes a mistake that sends his life , and the lives of those around him , spiraling into ruin . sound familiar ? this is the classic story pattern for greek tragedy . for thousands of years , we 've spun spellbinding tales that fit this pattern , and modern storytellers around the world continue to do so . three critical story components influenced by aristotle 's `` poetics '' help us understand the allure . first , the tragic hero should be elevated in rank and ability , but also relatable . perhaps he is a king , or extraordinary in some other way . but because you and i are neither unusually good nor unusually bad , neither is the hero . and he has one particular tragic flaw , or hamartia , something like ambition , tyranny , stubbornness , or excess pride that causes him to make a critical mistake . and from that mistake comes disaster and downfall . as an example of these elements in action , let 's look to sophocles 's `` oedipus rex , '' about a man who does n't know he was adopted , and is warned by an oracle that he 's destined to murder his father and marry his mother . in trying to escape this fate , he kills a man who wo n't get out of his way at a crossroad . he then cleverly answers the riddle of the monstrous sphynx , freeing the kingdom of thebes from a plague . he marries the widowed queen and becomes king . but after he finds out that the murdered man was his father , and the queen he married is his mother , oedipus gouges out his eyes and retreats into the wilderness . at the beginning of his story , oedipus is elevated in ability , and he 's elevated in rank . he 's neither unusually evil nor saintly . he 's relatable . notice the height of the fall . once a king , but now homeless and blind . it 's more tragic , after all , if a king falls from a tall throne than if a jester falls off his step stool . oedipus 's tragic flaw is hubris , or excessive pride , and it causes him to attempt to avoid the fate prophesied for him , which is exactly what makes it happen . he 's a particularly unlucky soul because his mistake of killing his father and marrying his mother is done in complete ignorance . of course , these narrative principles transcend classic greek tragedy . in shakespeare 's canon , we see hamlet 's indecisiveness lead to a series of bad decisions , or perhaps non-decisions , that culminate in the death of almost every character in the play , and macbeth 's ambition catapults him to the top before sending him careening to his grave . even modern pop culture staples like `` game of thrones '' and `` the dark knight '' resonate with the tropes aristotle identified over 2000 years ago . so what 's the point of all of this suffering ? according to aristotle , and many scholars since , a good tragedy can evoke fear and pity in the audience : fear of falling victim to the same or similar catastrophe , and pity for the height of the hero 's downfall . ideally , after watching these tragic events unfold , we experience catharsis , a feeling of relief and emotional purification . not everyone agrees why this happens . it may be that empathizing with the hero allows us to experience and release strong emotions that we keep bottled up , or maybe it just lets us forget about our own problems for a little while . but regardless of how you feel when you watch poor oedipus , never has there been a more salient reminder that no matter how bad things get , at least you did n't kill your father and marry your mother .
|
three critical story components influenced by aristotle 's `` poetics '' help us understand the allure . first , the tragic hero should be elevated in rank and ability , but also relatable . perhaps he is a king , or extraordinary in some other way .
|
which of the following is not a component of the tragic hero ?
|
translator : tom carter reviewer : bedirhan cinar lawn signs sprouting everywhere . round-the-clock ads on radio and television . the phone rings . it 's a robo-call from the president , or his opponent , asking for your money , and your vote . and while you 're at it , watch their youtube videos and like them on facebook . election time . we all know the look and feel of modern campaigns . but what was it like in the early days of the republic , when , say , george washington ran for office ? well , in fact , he did n't run . when washington became the first president in 1789 , there were no political parties , no conventions or primaries , no campaign , no election season . not really any candidates . even the year was odd . literally . 1789 was the only presidential election ever held in an odd year . after the framers invented the constitution and the presidency 225 years ago , the country set about the business of choosing its first executive . agreeing with ben franklin , many people thought `` the first man at the helm will be a good one , '' and by that , franklin meant george washington . greatest hero of the revolution , washington presided over the convention that created the constitution , rarely speaking . he never discussed the job of president , or of wanting it . and when the first presidential election took place , it was a crazy-quilt affair , with many hands stitching the pattern . under the new constitution , each state was given a number of electors . who would cast a vote for two names . the man with the most votes would be president , the second-place finisher was vice president . ah , but who picked the electors ? that was left up to the states . six of them let the people decide , or at least white men over 21 who owned property . in new jersey , some women voted , a right later taken away . but in other states , the legislature picked the electors . at that time , many people thought democracy was one step away from mob rule and a decision this important should be left to wiser men . these electors then voted for president . all the states had to do was get their votes in on time . but there were glitches . only 10 of the 13 states voted . rhode island and north carolina had n't ratified the constitution and could n't vote . new york missed the deadline for naming its electors , and also was not counted . when the votes were tallied , it was unanimous . george washington won easily . john adams trailed far behind , finishing second , and became the vice president . told of his victory , george washington was not surprised . at mount vernon , his bags were already packed . he moved to new york city , the nation 's temporary capital , and he would have to figure out just what a president was supposed to do . since that first election , american democracy and elections have come a long way . the constitution has been changed to open up voting to more people : black men , women , native americans , and eighteen-year-olds included . getting that basic right extended to all those people has been a long , hard struggle . so when you think you ca n't stand any more of those lawn signs , and tv ads , just remember : the right to vote was n't always for everyone , and that 's a piece of history worth knowing .
|
under the new constitution , each state was given a number of electors . who would cast a vote for two names . the man with the most votes would be president , the second-place finisher was vice president . ah , but who picked the electors ?
|
of the thirteen original states , how many cast votes for president in 1789 ?
|
denis diderot left a dungeon outside paris on november 3 , 1749 . he 'd had his writing burned in public before , but this time , he 'd gotten locked up under royal order for an essay about a philosopher 's death bed rejection of god . to free himself , denis promised never to write things like that again . so he got back to work on something a little like that , only way worse , and much bigger . in 1745 , publisher andré le breton had hired diderot to adapt the english cyclopedia , or a universal dictionary of arts and sciences for french subscribers . a broke writer , diderot survived by translating , tutoring , and authoring sermons for priests , and a pornographic novel once . le breton paired him with co-editor jean le rond d'alembert , a math genius found on a church doorstep as a baby . technical dictionaries , like the cyclopedia , were n't new , but no one had attempted one publication covering all knowledge , so they did . the two men organized the french enlightenment 's brightest stars to produce the first encyclopedia , or rational dictionary of the arts , sciences , and crafts . assembling every essential fact and principle in , as it turned out , over 70,000 entries , 20,000,000 words in 35 volumes of text and illustrations created over three decades of researching , writing , arguging , smuggling , backstabbing , law-breaking , and alphabetizing . to organize the work , diderot adapted francis bacon 's `` classification of knowledge '' into a three-part system based on the mind 's approaches to reality : memory , reason , and imagination . he also emphasized the importance of commerce , technology , and crafts , poking around shops to study the tools and techniques of parisian laborers . to spotlight a few of the nearly 150 philosoph contributers , jean jacques rousseau , diderot 's close friend , wrote much of the music section in three months , and was never reimbursed for copy fees . his entry on political economy holds ideas he 'd later develop further in `` the social contract . '' d'alembert wrote the famous preliminary discourse , a key statement of the french enlightenment , championing independent investigative reasoning as the path to progress . louis de jaucourt wrote a quarter of the encyclopedia , 18,000 articles , 5,000,000 words , unpaid . louis once spent 20 years writing a book on anatomy , shipped it to amsterdam to be published uncensored , and the ship sank . voltaire contributed entries , among them history , elegance , and fire . diderot 's entries sometimes exhibit slight bias . in `` political authority , '' he dismantled the divine right of kings . under `` citizen , '' he argued a state was strongest without great disparity in wealth . not surprising from the guy who wrote poetry about mankind strangling its kings with the entrails of a priest . so diderot 's masterpiece was n't a hit with the king or highest priest . upon release of the first two volumes , louie xv banned the whole thing but enjoyed his own copy . pope clement xiii ordered it burned . it was `` dangerous , '' `` reprehensible , '' as well as `` written in french , '' and in `` the most seductive style . '' he declared readers excommunicated and wanted diderot arrested on sight . but diderot kept a step ahead of being shut down , smuggling proofs outside france for publication , and getting help from allies in the french regime , including the king 's mistress , madame de pompadour , and the royal librarian and censor , malesherbes , who tipped diderot off to impending raids , and even hid diderot 's papers at his dad 's house . still , he faced years of difficulty . d'alembert dropped out . rousseau broke off his friendship over a line in a play . worse yet , his publisher secretly edited some proofs to read less radically . the uncensored pages reappeared in russia in 1933 , long after diderot had considered the work finished and died at lunch . the encyclopedia he left behind is many things : a cornerstone of the enlightenment , a testament to france 's crisis of authority , evidence of popular opinions migration from pulpit and pew to cafe , salon , and press . it even has recipes . it 's also irrepressibly human , as you can tell from diderot 's entry about a plant named aguaxima . read it yourself , preferably out loud in a french accent .
|
voltaire contributed entries , among them history , elegance , and fire . diderot 's entries sometimes exhibit slight bias . in `` political authority , '' he dismantled the divine right of kings .
|
what did diderot not criticize in the encyclopedia ?
|
on a december afternoon in chicago during the middle of world war ii , scientists cracked open the nucleus at the center of the uranium atom and turned nuclear mass into energy over and over again . they did this by creating for the first time a chain reaction inside a new engineering marvel : the nuclear reactor . since then , the ability to mine great amounts of energy from uranium nuclei has led some to bill nuclear power as a plentiful utopian source of electricity . a modern nuclear reactor generates enough electricity from one kilogram of fuel to power an average american household for nearly 34 years . but rather than dominate the global electricity market , nuclear power has declined from an all-time high of 18 % in 1996 to 11 % today . and it 's expected to drop further in the coming decades . what happened to the great promise of this technology ? it turns out nuclear power faces many hurdles , including high construction costs and public opposition . and behind these problems lie a series of unique engineering challenges . nuclear power relies on the fission of uranium nuclei and a controlled chain reaction that reproduces this splitting in many more nuclei . the atomic nucleus is densely packed with protons and neutrons bound by a powerful nuclear force . most uranium atoms have a total of 238 protons and neutrons , but roughly one in every 140 lacks three neutrons , and this lighter isotope is less tightly bound . compared to its more abundant cousin , a strike by a neutron easily splits the u-235 nuclei into lighter , radioactive elements called fission products , in addition to two to three neutrons , gamma rays , and a few neutrinos . during fission , some nuclear mass transforms into energy . a fraction of the newfound energy powers the fast-moving neutrons , and if some of them strike uranium nuclei , fission results in a second larger generation of neutrons . if this second generation of neutrons strike more uranium nuclei , more fission results in an even larger third generation , and so on . but inside a nuclear reactor , this spiraling chain reaction is tamed using control rods made of elements that capture excess neutrons and keep their number in check . with a controlled chain reaction , a reactor draws power steadily and stably for years . the neutron-led chain reaction is a potent process driving nuclear power , but there 's a catch that can result in unique demands on the production of its fuel . it turns out , most of the neutrons emitted from fission have too much kinetic energy to be captured by uranium nuclei . the fission rate is too low and the chain reaction fizzles out . the first nuclear reactor built in chicago used graphite as a moderator to scatter and slow down neutrons just enough to increase their capture by uranium and raise the rate of fission . modern reactors commonly use purified water as a moderator , but the scattered neutrons are still a little too fast . to compensate and keep up the chain reaction , the concentration of u-235 is enriched to four to seven times its natural abundance . today , enrichment is often done by passing a gaseous uranium compound through centrifuges to separate lighter u-235 from heavier u-238 . but the same process can be continued to highly enrich u-235 up to 130 times its natural abundance and create an explosive chain reaction in a bomb . methods like centrifuge processing must be carefully regulated to limit the spread of bomb-grade fuel . remember , only a fraction of the released fission energy goes into speeding up neutrons . most of the nuclear power goes into the kinetic energy of the fission products . those are captured inside the reactor as heat by a coolant , usually purified water . this heat is eventually used to drive an electric turbine generator by steam just outside the reactor . water flow is critical not only to create electricity , but also to guard against the most dreaded type of reactor accident , the meltdown . if water flow stops because a pipe carrying it breaks , or the pumps that push it fail , the uranium heats up very quickly and melts . during a nuclear meltdown , radioactive vapors escape into the reactor , and if the reactor fails to hold them , a steel and concrete containment building is the last line of defense . but if the radioactive gas pressure is too high , containment fails and the gasses escape into the air , spreading as far and wide as the wind blows . the radioactive fission products in these vapors eventually decay into stable elements . while some decay in a few seconds , others take hundreds of thousands of years . the greatest challenge for a nuclear reactor is to safely contain these products and keep them from harming humans or the environment . containment does n't stop mattering once the fuel is used up . in fact , it becomes an even greater storage problem . every one to two years , some spent fuel is removed from reactors and stored in pools of water that cool the waste and block its radioactive emissions . the irradiated fuel is a mix of uranium that failed to fission , fission products , and plutonium , a radioactive material not found in nature . this mix must be isolated from the environment until it has all safely decayed . many countries propose deep time storage in tunnels drilled far underground , but none have been built , and there 's great uncertainty about their long-term security . how can a nation that has existed for only a few hundred years plan to guard plutonium through its radioactive half-life of 24,000 years ? today , many nuclear power plants sit on their waste , instead , storing them indefinitely on site . apart from radioactivity , there 's an even greater danger with spent fuel . plutonium can sustain a chain reaction and can be mined from the waste to make bombs . storing spent fuel is thus not only a safety risk for the environment , but also a security risk for nations . who should be the watchmen to guard it ? visionary scientists from the early years of the nuclear age pioneered how to reliably tap the tremendous amount of energy inside an atom - as an explosive bomb and as a controlled power source with incredible potential . but their successors have learned humbling insights about the technology 's not-so-utopian industrial limits . mining the subatomic realm makes for complex , expensive , and risky engineering .
|
nuclear power relies on the fission of uranium nuclei and a controlled chain reaction that reproduces this splitting in many more nuclei . the atomic nucleus is densely packed with protons and neutrons bound by a powerful nuclear force . most uranium atoms have a total of 238 protons and neutrons , but roughly one in every 140 lacks three neutrons , and this lighter isotope is less tightly bound . compared to its more abundant cousin , a strike by a neutron easily splits the u-235 nuclei into lighter , radioactive elements called fission products , in addition to two to three neutrons , gamma rays , and a few neutrinos . during fission , some nuclear mass transforms into energy .
|
a sub-atomic event in which a uranium nucleus splits into lighter radioactive materials , neutrons , gamma rays , and neutrinos is called a :
|
every day of your life , you move through systems of power that other people made . do you sense them ? do you understand power ? do you realize why it matters ? power is something we are often uncomfortable talking about . that 's especially true in civic life , how we live together in community . in a democracy , power is supposed to reside with the people , period . any further talk about power and who really has it seems a little dirty , maybe even evil . but power is no more inherently good or evil than fire or physics . it just is . it governs how any form of government works . it determines who gets to determine the rules of the game . so learning how power operates is key to being effective , being taken seriously , and not being taken advantage of . in this lesson , we 'll look at where power comes from , how it 's exercised and what you can do to become more powerful in public life . let 's start with a basic definition . power is the ability to make others do what you would have them do . of course , this plays out in all arenas of life , from family to the workplace to our relationships . our focus is on the civic arena , where power means getting a community to make the choices and to take the actions that you want . there are six main sources of civic power . first , there 's physical force and a capacity for violence . control of the means of force , whether in the police or a militia , is power at its most primal . a second core source of power is wealth . money creates the ability to buy results and to buy almost any other kind of power . the third form of power is state action , government . this is the use of law and bureaucracy to compel people to do or not do certain things . in a democracy , for example , we the people , theoretically , give government its power through elections . in a dictatorship , state power emerges from the threat of force , not the consent of the governed . the fourth type of power is social norms or what other people think is okay . norms do n't have the centralized machinery of government . they operate in a softer way , peer to peer . they can certainly make people change behavior and even change laws . think about how norms around marriage equality today are evolving . the fifth form of power is ideas . an idea , individual liberties , say , or racial equality , can generate boundless amounts of power if it motivates enough people to change their thinking and actions . and so the sixth source of power is numbers , lots of humans . a vocal mass of people creates power by expressing collective intensity of interest and by asserting legitimacy . think of the arab spring or the rise of the tea party . crowds count . these are the six main sources of power , what power is . so now , let 's think about how power operates . there are three laws of power worth examining . law number one : power is never static . it 's always either accumulating or decaying in a civic arena . so if you are n't taking action , you 're being acted upon . law number two : power is like water . it flows like a current through everyday life . politics is the work of harnessing that flow in a direction you prefer . policymaking is an effort to freeze and perpetuate a particular flow of power . policy is power frozen . law number three : power compounds . power begets more power , and so does powerlessness . the only thing that keeps law number three from leading to a situation where only one person has all the power is how we apply laws one and two . what rules do we set up so that a few people do n't accumulate too much power , and so that they ca n't enshrine their privilege in policy ? that 's the question of democracy , and you can see each of these laws at work in any news story . low wage workers organize to get higher pay . oil companies push to get a big pipeline approved . gay and lesbian couples seek the legal right to marry . urban parents demand school vouchers . you may support these efforts or not . whether you get what you want depends on how adept you are with power , which brings us finally to what you can do to become more powerful in public life . here , it 's useful to think in terms of literacy . your challenge is to learn how to read power and write power . to read power means to pay attention to as many texts of power as you can . i do n't mean books only . i mean seeing society as a set of texts . do n't like how things are in your campus or city or country ? map out who has what kind of power , arrayed in what systems . understand why it turned out this way , who 's made it so , and who wants to keep it so . study the strategies others in such situations used : frontal attack or indirection , coalitions or charismatic authority . read so you may write . to write power requires first that you believe you have the right to write , to be an author of change . you do . as with any kind of writing , you learn to express yourself , speak up in a voice that 's authentic . organize your ideas , then organize other people . practice consensus building . practice conflict . as with writing , it 's all about practice . every day you have a chance to practice , in your neighborhood and beyond . set objectives , then bigger ones . watch the patterns , see what works . adapt , repeat . this is citizenship . in this short lesson , we 've explored where civic power comes from , how it works and what you can do to exercise it . one big question remaining is the `` why '' of power . do you want power to benefit everyone or only you ? are your purposes pro-social or anti-social ? this question is n't about strategy . it 's about character , and that 's another set of lessons . but remember this : power plus character equals a great citizen , and you have the power to be one .
|
policymaking is an effort to freeze and perpetuate a particular flow of power . policy is power frozen . law number three : power compounds . power begets more power , and so does powerlessness . the only thing that keeps law number three from leading to a situation where only one person has all the power is how we apply laws one and two .
|
what strategies can you use to gain more power in public life ?
|
the geography of our planet is in flux . each continent has ricocheted around the globe on one or more tectonic plates , changing quite dramatically with time . today , we 'll focus on north america and how its familiar landscape and features emerged over hundreds of millions of years . our story begins about 750 million years ago . as the super continent rodinia becomes unstable , it rifts along what 's now the west coast of north america to create the panthalassa ocean . you 're seeing an ancestral continent called laurentia , which grows over the next few hundred million years as island chains collide with it and add land mass . we 're now at 400 million years ago . off today 's east coast , the massive african plate inches westward , closing the ancient iapetus ocean . it finally collides with laurentia at 250 million years to form another supercontinent pangea . the immense pressure causes faulting and folding , stacking up rock to form the appalachian mountains . let 's fast forward a bit . about 100 million years later , pangea breaks apart , opening the southern atlantic ocean between the new north american plate and the african plate . we forge ahead , and now the eastward-moving farallon plate converges with the present-day west coast . the farallon plate 's greater density makes it sink beneath north america . this is called subduction , and it diffuses water into the magma-filled mantle . that lowers the magma 's melting point and makes it rise into the overlying north american plate . from a subterranean chamber , the magma travels upwards and erupts along a chain of volcanos . magma still deep underground slowly cools , crystallizing to form solid rock , including the granite now found in yosemite national park and the sierra nevada mountains . we 'll come back to that later . now , it 's 85 million years ago . the farallon plate becomes less steep , causing volcanism to stretch eastward and eventually cease . as the farallon plate subducts , it compresses north america , thrusting up mountain ranges like the rockies , which extend over 3,000 miles . soon after , the eurasian plate rifts from north america , opening the north atlantic ocean . we 'll fast forward again . the colorado plateau now uplifts , likely due to a combination of upward mantle flow and a thickened north american plate . in future millennia , the colorado river will eventually sculpt the plateau into the epic grand canyon . 30 million years ago , the majority of the farallon plate sinks into the mantle , leaving behind only small corners still subducting . the pacific and north american plates converge and a new boundary called the san andreas fault forms . here , north america moves to the south , sliding against the pacific plate , which shifts to the north . this plate boundary still exists today , and moves about 30 millimeters per year capable of causing devastating earthquakes . the san andreas also pulls apart western north america across a wide rift zone . this extensional region is called the basin and range province , and through uplift and erosion , is responsible for exposing the once deep granite of yosemite and the sierra nevada . another 15 million years off the clock , and magma from the mantle burns a giant hole into western north america , periodically erupting onto the surface . today , this hotspot feeds an active supervolcano beneath yellowstone national park . it has n't erupted in the last 174,000 years , but if it did , its sheer force could blanket most of the continent with ash that would blacken the skies and threaten humanity . the yellowstone supervolcano is just one reminder that the earth continues to seethe below our feet . its mobile plates put the planet in a state of constant flux . in another few hundred million years , who knows how the landscape of north america will have changed . as the continent slowly morphs into something unfamiliar , only geological time will tell .
|
let 's fast forward a bit . about 100 million years later , pangea breaks apart , opening the southern atlantic ocean between the new north american plate and the african plate . we forge ahead , and now the eastward-moving farallon plate converges with the present-day west coast .
|
the theory of plate tectonics is a relatively new idea , developed in the mid-20th century following the discovery of tectonic features on seafloors . can you imagine our explanation of faults , earthquakes , mountains , and rifting before the plate tectonic revolution ?
|
mysteries of vernacular : yankee , a new england resident or , more generally , a person who lives in or is from the united states . though the origin of yankee is uncertain , this all-american word most likely descended from the dutch moniker janke , a diminutive meaning little jan , or little john . in the 17th century , janke was the common nickname of dutch sailors , pirates in particular . a dutch pirate ship operating in the west indies was even called the yankee . over the years , yankee transformed from a pirate 's nickname into a general term of contempt . in 1758 , british general james wolfe used yankee as a pejorative term for the colonists under his supervision . but the insult was n't limited to soldiers . yankee quickly came to mean new englander , and by the 1780s , it was used to look down upon any american . during the revolution , colonists co-opted yankee and transformed it into a mark of national honor . the civil war , however , intensified the derisive definition when it was used by southerners to mock members of the union . today , it carries much less emotion , unless , of course , we 're talking about baseball .
|
mysteries of vernacular : yankee , a new england resident or , more generally , a person who lives in or is from the united states . though the origin of yankee is uncertain , this all-american word most likely descended from the dutch moniker janke , a diminutive meaning little jan , or little john . in the 17th century , janke was the common nickname of dutch sailors , pirates in particular . a dutch pirate ship operating in the west indies was even called the yankee .
|
what does janke mean ?
|
bees are very busy little matchmakers . wingmen in every sense of the word . you see , the bees ' side of the whole `` birds and the bees '' business is to help plants find mates and reproduce . in their work as pollinators , honeybees are integral to the production of nearly 1/3 of the food that we eat . and these bees , dutifully helping lonely plants have sex , are n't alone . but rather are part of a very complex network of matchmaking creatures , critical for the pollination of natural ecosystems and crops . plants in many natural ecosystems need help to have sex . like many of us , they 're too busy to find a relationship . they have too much photosynthesis to do , and they ca n't find the time to evolve feet and walk to a singles bar . those places are called meat markets for a reason , because plants ca n't walk . so they need matchmaker pollinators to transport their pollen grains to flowers of the same plant species , and they pay these pollinators with food . today , around 170,000 plant species receive pollination services from more than 200,000 pollinator species . pollinators include many species of bees , butterflies , moths , flies , wasps , beetles , even birds and bats , who together help pollinate many species of trees , shrubs and other flowering plants . in return , flowering plants are an abundant and diverse food source for pollinators . for instance , fossil records suggest bees may have evolved from wasps that gave up hunting after they acquired a taste for nectar . plant pollinator networks are everywhere . ecologists record these networks in the field by observing which pollinators visit which plants , or by analyzing the identity of pollen loads on their bodies . networks , registered in these ways , contain from 20 to 800 species . these networks show a repeated structure , or architecture . pollinators interact with plants in a very heterogenous way . most plants are specialists , they have only one or a few matchmakers . meanwhile , only a few generalist plants hire a diverse team of matchmakers , getting visits from almost all the pollinators of the network . the same occurs with pollinators . most are specialists that feed on only a few plant species , while a few pollinators , including the honeybee usually , are generalists , busily feeding from and matchmaking for almost all the plant species in that ecosystem . what 's interesting is that specialists and generalists across both plants and pollinators , sort themselves out in a particular pattern . most pollinator networks , for which we have data , are nested . in a nested network , specialists tend to interact more with generalists than with other specialists . this is because if you 're a specialist plant , and your only matchmaker also specializes on you as its only food source , you 're each more vulnerable to extinction . so , you 're better off specializing on a generalist pollinator that has other sources of food to ensure its persistence in bad years . the same goes if you 're a specialist pollinator . you 're better off in the long run specializing on a generalist plant that gets pollinated by other species in times when you 're not around to help . finally , in addition to nestedness , the networks are usually modular . this means that the species in a network are compartmentalized into modules of plants and animals that interact more with each other than with species in other modules . think of them like social cliques . a plant or pollinator dying off will effect the species in its module , but those effects will be less severe on the rest of the network . why 's all that important ? because plant pollinator network structure effects the stability of ecosystems . heterogeneous distribution , nestedness and modularity enable networks to better prevent and respond to extinctions . that 's critical because nature is never static . some species may not show up every year . plants flower at different times . pollinators mature on varying schedules . generalist pollinators have to adapt their preferences depending on who 's flowering when . so from one flowering season to the next , the participants and patterns of matchmaking can drastically change . with all those variables , you can understand the importance of generalist pollinators , like bees , to the stability of not only a crop harvest , but the entire network of plants and pollinators we see in nature , and rely on for life . next time you see a bee fly by , remember that it belongs to a complex network of matchmakers critical to the love lives of plants all around you .
|
you 're better off in the long run specializing on a generalist plant that gets pollinated by other species in times when you 're not around to help . finally , in addition to nestedness , the networks are usually modular . this means that the species in a network are compartmentalized into modules of plants and animals that interact more with each other than with species in other modules .
|
in addition to nestedness , the networks are usually “ modular. ” what a modular structure means and which is the advantage of a modular structure ?
|
you 've been stranded thousands of miles from home with no money or possessions . such a predicament would make many people despair and curse their awful fate . but for zeno of cyprus , it became the foundation of his life 's work and legacy . the once wealthy merchant lost everything when he was shipwrecked in athens around 300 bce . with not much else to do , he wandered into a book shop , became intrigued by reading about socrates , and proceeded to seek out and study with the city 's noted philosophers . as zeno began educating his own students , he originated the philosophy known as stoicism , whose teachings of virtue , tolerance , and self-control have inspired generations of thinkers and leaders . the name stoicism comes from the stoa poikile , the decorated public colonnade where zeno and his disciples gathered for discussion . today , we colloquially use the word stoic to mean someone who remains calm under pressure and avoids emotional extremes . but while this captures important aspects of stoicism , the original philosophy was more than just an attitude . the stoics believed that everything around us operates according to a web of cause and effect , resulting in a rational structure of the universe , which they called logos . and while we may not always have control over the events affecting us , we can have control over how we approach things . rather than imagining an ideal society , the stoic tries to deal with the world as it is while pursuing self-improvement through four cardinal virtues : practical wisdom , the ability to navigate complex situations in a logical , informed , and calm manner ; temperance , the exercise of self-restraint and moderation in all aspects of life ; justice , treating others with fairness even when they have done wrong ; and courage , not just in extraordinary circumstances , but facing daily challenges with clarity and integrity . as seneca , one of the `most famous roman stoics wrote , `` sometimes , even to live is an act of courage . '' but while stoicism focuses on personal improvement , it 's not a self-centered philosophy . at a time when roman laws considered slaves as property , seneca called for their humane treatment and stressed that we all share the same fundamental humanity . nor does stoicism encourage passivity . the idea is that only people who have cultivated virtue and self-control in themselves can bring positive change in others . one of the most famous stoic writers was also one of rome 's greatest emperors . over the course of his 19-year reign , stoicism gave marcus aurelius the resolve to lead the empire through two major wars , while dealing with the loss of many of his children . centuries later , marcus 's journals would guide and comfort nelson mandela through his 27-year imprisonment during his struggle for racial equality in south africa . after his release and eventual victory , mandela stressed peace and reconciliation , believing that while the injustices of the past could n't be changed , his people could confront them in the present and seek to build a better , more just future . stoicism was an active school of philosophy for several centuries in greece and rome . as a formal institution , it faded away , but its influence has continued to this day . christian theologians , such as thomas aquinas , have admired and adopted its focus on the virtues , and there are parallels between stoic ataraxia , or tranquility of mind , and the buddhist concept of nirvana . one particularly influential stoic was the philosopher epictetus who wrote that suffering stems not from the events in our lives , but from our judgements about them . this has resonated strongly with modern psychology and the self-help movement . for example , rational emotive behavioral therapy focuses on changing the self-defeating attitudes people form about their life circumstances . there 's also viktor frankl 's logotherapy . informed by frankl 's own time as a concentration camp prisoner , logotherapy is based on the stoic principle that we can harness our will power to fill our lives with meaning , even in the bleakest situations .
|
the name stoicism comes from the stoa poikile , the decorated public colonnade where zeno and his disciples gathered for discussion . today , we colloquially use the word stoic to mean someone who remains calm under pressure and avoids emotional extremes . but while this captures important aspects of stoicism , the original philosophy was more than just an attitude .
|
which of the following is not a stoic virtue :
|
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 !
|
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 ?
|
which is not an example of a rule in a fictional world ?
|
how did adolf hitler , a tyrant who orchestrated one of the largest genocides in human history , rise to power in a democratic country ? the story begins at the end of world war i . with the successful allied advance in 1918 , germany realized the war was unwinnable and signed an armistice ending the fighting . as its imperial government collapsed , civil unrest and worker strikes spread across the nation . fearing a communist revolution , major parties joined to suppress the uprisings , establishing the parliamentary weimar republic . one of the new government 's first tasks was implementing the peace treaty imposed by the allies . in addition to losing over a tenth of its territory and dismantling its army , germany had to accept full responsibility for the war and pay reparations , debilitating its already weakened economy . all this was seen as a humiliation by many nationalists and veterans . they wrongly believed the war could have been won if the army had n't been betrayed by politicians and protesters . for hitler , these views became obsession , and his bigotry and paranoid delusions led him to pin the blame on jews . his words found resonance in a society with many anti-semitic people . by this time , hundreds of thousands of jews had integrated into german society , but many germans continued to perceive them as outsiders . after world war i , jewish success led to ungrounded accusations of subversion and war profiteering . it can not be stressed enough that these conspiracy theories were born out of fear , anger , and bigotry , not fact . nonetheless , hitler found success with them . when he joined a small nationalist political party , his manipulative public speaking launched him into its leadership and drew increasingly larger crowds . combining anti-semitism with populist resentment , the nazis denounced both communism and capitalism as international jewish conspiracies to destroy germany . the nazi party was not initially popular . after they made an unsuccessful attempt at overthrowing the government , the party was banned , and hitler jailed for treason . but upon his release about a year later , he immediately began to rebuild the movement . and then , in 1929 , the great depression happened . it led to american banks withdrawing their loans from germany , and the already struggling german economy collapsed overnight . hitler took advantage of the people 's anger , offering them convenient scapegoats and a promise to restore germany 's former greatness . mainstream parties proved unable to handle the crisis while left-wing opposition was too fragmented by internal squabbles . and so some of the frustrated public flocked to the nazis , increasing their parliamentary votes from under 3 % to over 18 % in just two years . in 1932 , hitler ran for president , losing the election to decorated war hero general von hindenburg . but with 36 % of the vote , hitler had demonstrated the extent of his support . the following year , advisors and business leaders convinced hindenburg to appoint hitler as chancellor , hoping to channel his popularity for their own goals . though the chancellor was only the administrative head of parliament , hitler steadily expanded the power of his position . while his supporters formed paramilitary groups and fought protestors in streets . hitler raised fears of a communist uprising and argued that only he could restore law and order . then in 1933 , a young worker was convicted of setting fire to the parliament building . hitler used the event to convince the government to grant him emergency powers . within a matter of months , freedom of the press was abolished , other parties were disbanded , and anti-jewish laws were passed . many of hitler 's early radical supporters were arrested and executed , along with potential rivals , and when president hindenburg died in august 1934 , it was clear there would be no new election . disturbingly , many of hitler 's early measures did n't require mass repression . his speeches exploited people 's fear and ire to drive their support behind him and the nazi party . meanwhile , businessmen and intellectuals , wanting to be on the right side of public opinion , endorsed hitler . they assured themselves and each other that his more extreme rhetoric was only for show . decades later , hitler 's rise remains a warning of how fragile democratic institutions can be in the face of angry crowds and a leader willing to feed their anger and exploit their fears .
|
as its imperial government collapsed , civil unrest and worker strikes spread across the nation . fearing a communist revolution , major parties joined to suppress the uprisings , establishing the parliamentary weimar republic . one of the new government 's first tasks was implementing the peace treaty imposed by the allies .
|
why was the weimar republic immediately unpopular with the german people ?
|
imagine as a thought experiment that you live in a small village and depend on the local fish pond for food . you share the pond with three other villagers . the pond starts off with a dozen fish , and the fish reproduce . for every two fish , there will be one baby added each night . so , in order to maximize your supply of food , how many fish should you catch each day ? take a moment to think about it . assume baby fish grow to full size immediately and that the pond begins at full capacity , and ignore factors like the sex of the fish you catch . the answer ? one , and it 's not just you . the best way to maximize every villager 's food supply is for each fisherman to take just one fish each day . here 's how the math works . if each villager takes one fish , there will be eight fish left over night . each pair of fish produces one baby , and the next day , the pond will be fully restocked with twelve fish . if anyone takes more than one , the number of reproductive pairs drops , and the population wo n't be able to bounce back . eventually , the fish in the lake will be gone , leaving all four villagers to starve . this fish pond is just one example of a classic problem called the tragedy of the commons . the phenomenon was first described in a pamphlet by economist william forster lloyd in 1833 in a discussion of the overgrazing of cattle on village common areas . more than 100 years later , ecologist garrett hardin revived the concept to describe what happens when many individuals all share a limited resource , like grazing land , fishing areas , living space , even clean air . hardin argued that these situations pit short-term self-interest against the common good , and they end badly for everyone , resulting in overgrazing , overfishing , overpopulation , pollution , and other social and environmental problems . the key feature of a tragedy of the commons is that it provides an opportunity for an individual to benefit him or herself while spreading out any negative effects across the larger population . to see what that means , let 's revisit our fish pond . each individual fisherman is motivated to take as many fish as he can for himself . meanwhile , any decline in fish reproduction is shared by the entire village . anxious to avoid losing out to his neighbors , a fisherman will conclude that it 's in his best interest to take an extra fish , or two , or three . unfortunately , this is the same conclusion reached by the other fisherman , and that 's the tragedy . optimizing for the self in the short term is n't optimal for anyone in the long term . that 's a simplified example , but the tragedy of the commons plays out in the more complex systems of real life , too . the overuse of antibiotics has led to short-term gains in livestock production and in treating common illnesses , but it 's also resulted in the evolution of antibiotic-resistant bacteria , which threaten the entire population . a coal-fired power plant produces cheap electricity for its customers and profits for its owners . these local benefits are helpful in the short term , but pollution from mining and burning coal is spread across the entire atmosphere and sticks around for thousands of years . there are other examples , too . littering , water shortages , deforestation , traffic jams , even the purchase of bottled water . but human civilization has proven it 's capable of doing something remarkable . we form social contracts , we make communal agreements , we elect governments , and we pass laws . all this to save our collective selves from our own individual impulses . it is n't easy , and we certainly do n't get it right nearly all of the time . but humans at our best have shown that we can solve these problems and we can continue to do so if we remember hardin 's lesson . when the tragedy of the commons applies , what 's good for all of us is good for each of us .
|
eventually , the fish in the lake will be gone , leaving all four villagers to starve . this fish pond is just one example of a classic problem called the tragedy of the commons . the phenomenon was first described in a pamphlet by economist william forster lloyd in 1833 in a discussion of the overgrazing of cattle on village common areas .
|
which of the following quotes seems to be taken directly from the tragedy of the commons ( nature , 1968 ) ?
|
to understand what 's happening with greece and the eurozone , think about a dinner party . if you 're cooking just for yourself and your spouse , it 's easy : you make something you both like . but if you 've got guests , things get harder . if you need to accommodate a vegetarian , and someone who is gluten free , and someone with a soy allergy , your options get really limited . and that 's the problem with europe 's idea of having a whole bunch of countries all use the same currency . so greece 's economy is in a disaster . a quarter of the population is unemployed , and it has this very high debt burden . normally , if you 've got really high unemployment , what happens is that a country makes its currency cheaper by printing extra money . that makes its products cheaper on world markets , it makes it a more attractive tourist destination , and it means that foreign investors can get great bargains . but if unemployment is really low , a country likes to have an expensive currency . that increases people 's purchasing power and it keeps prices down . and in europe , you have a bunch of economies that are really different . a price of euros that 's appropriate for greece , where they have a 25 % unemployment rate is way too low for germany , where the unemployment rate is below 5 % . and greece 's problem is that it 's small , poor , and geographically isolated from the rest of the eurozone . it 's like the only vegetarian at a barbeque , except when it comes to currencies , there 's no side dishes . and so there 's plenty of specific decisions we can second-guess , plenty of things greece did and various banks did that we can question , but fundamentally having all these countries come to a dinner party with only one dish on the menu was a mistake . the euro was a project that europe set about on for really political reasons . it was a symbol of their determination to have peace on the continent , but they did n't really take the economics of it seriously . so greece joins the euro in 2001 and initially , it works out great for greece because all of a sudden everyone was like 'yeah , sure , let 's lend them money . ' so they borrowed lots and lots and lots of euros , except that did n't change the fact that their economy is a lot weaker than some of the other european countries . so to really work , you would need a much , much , much closer union , where you had big financial transfers coming from the richer places to the poorer places all the time . in the united states , the poor states like kentucky , mississippi , alabama , they 're constantly getting money from the richer states like massachusetts , california , new york , through the welfare system , through social security , through medicare , through medicaid . and you know , people may complain about this or that program , but we do n't dispute the idea that it 's all one country so money is going to circulate around . europeans , you know , they just do n't feel that way . germans are willing to support poor german people , but they do n't want to support greek people with their tax dollars . so they 're kind of like half-way integrated in a way that does n't really work .
|
to understand what 's happening with greece and the eurozone , think about a dinner party . if you 're cooking just for yourself and your spouse , it 's easy : you make something you both like .
|
the narrator compares the eu to having guests over for dinner . according to that comparison , greece is :
|
okay weíre going to be looking today at copper . this is something looking back at the old video , itís a short video and there isnít any experimentation in it so i thought weíd do something a bit practical . copper is an element which people are very familiar with because itís such a characteristic coloured metal , sort of reddish colour , though it gets darker when oxide forms . but itís quite a soft metal and you can cut it quite easily if you have a cutter like this which has steel blades , it will just dig into the metal and it should just cut off . when you cut the metal you get this very nice , shiny , fresh surface coloured just like copper . this is a ball of copper , copper metal . as you might imagine itís a ball of metal so therefore it is quite dense and heavy . i mean itís not as dense as , i think steve told me this morning , that if we had a ball this size of plutonium he told me it would weigh about a kilo and a half so he thought . so itís not quite as heavy as that but still itís pretty heavy and dense . so this is a very , very nice sample of very fine copper wire . so the copper wire here is , what width is this ? this isö phew ! point zero , iím not even going toöthatís just too small , so itís point one of a millimetre . so inside the beaker weíve got a solution called sodium potassium tartrate , so no copper in there at the moment . weíre going to introduce that through this . this is a solution of copper sulphate . copper is very popular for architectural use because if you put it on the roofs of buildings it then reacts , particularly with carbon dioxide in the air , to give a very nice green colour . first of all though we need to heat this to about 50∞c , and to the sodium potassium tartrate we need to add some very weak , hydrogen peroxide so this is only 3 % hydrogen peroxide , so in it goes . we need to make sure they mix together which is why thereís a stirring bar at the bottom there stirring away . okay so thatís stirring nicely , so as i said sodium potassium tartrate and hydrogen peroxide and we need to add only one mill so thatís 1cm3 of the copper sulphate . the copper wire here is very , very high grade , this is grade one copper wire and itís point one of a millimetre in diameter and you can see the wonderful copperas lustre coming off the side there . what do you mean by grade one copper ? so this is very high purity , this is like 99.99 % copper , used for electronics fabrications and high quality research samples . itís also used for electrical wiring , in fact itís used so much that in a country like the uk each person has about 175 kilos of copper associated with each person , in the piping , the wiring and so on . the problem is that in many other countries , for example in china , people have very much less copper associated with them , there isnít so much electrical wiring in rural parts of china . and if everybody in china had the same amount of copper associated with them as those in england or america or canada there wouldnít be enough copper in all the known deposits around the world . copper is actually necessary for life , plants and animals use copper . but actually you can have a disease called wilsonís disease which basically your body canít metabolise copper properly , itís actually an inherited disease . ready ? whatís going on there is itís producing a lot of gas so itís reacting to form a complex . and itís going from the potassium tartrate complex there to well , its producing carbon dioxide and oxygen , mainly oxygen gas is being produced which is why youíre seeing the fizzing . and itís become copper oxide , cuprous oxide actually . copper is found as a metal lying around in various places in the world . i believe the name came from the island of cyprus in the middle of the mediterranean , but copper has always been know even in pre-historic times people found small amounts of copper . but as we use more and more copper people have had to dig deeper and deeper mines . the mine in chile where those very brave miners were entombed for more than two months and then rescued was a copper mine . and to get the metal that we need weíre going to have to go deeper and deeper and deeper into the earth . so what weíve got in there now is cuprous oxide itís copper 1 oxide . and itís actually gone from what was a kind of clear see-through , all right itís got a colour on it , but see-through solution to something thatís very cloudy . so what weíve got there is a precipitate of copper oxide . copper is very good because it has very high thermal and electrical conductivity . what that means is that heat flows through it very well and also electricity . if you make wires for electrical transmission out of copper , when the electricity goes through them you get very much less heating than say if you made the wires out of iron , and all this heating is of course lost energy . youíd do even better if you made the wires out of silver , but silver is too expensive . ok . so letís see if we can change this reaction back . so at the moment it started out as being about 50∞c and itís shot up to about 63∞c , i imagine it was even hotter than that when it originally changed colour . so weíll see if we can take it back , iíll put that back in . i actually bought this from the british geological survey which is just down the road from here , i think it is in keyworth i think . and i just saw this and it was a christmas present from my husband and i picked it out . i just think itís really cool actually . what did your husband think of getting that as a christmas present ? he knows what iím like ! so he buys these things for me he knows iím a bit of a magpie , i like to collect shiny things , and pretty things , thatís my copper . so the colour is gradually changing , itís gone from orange and now kind of a murky yellow . you can see itís kind of green now . and again a gradual change , it wasnít a sudden spontaneous straight back to being blue and see-through , you know clear . now weíve got back to that clear solution . and again you can see on the stirrer bar all the bubbles of the oxygen , little bit of c02 forming on that . most organisms , you and me , use iron in our blood to transport oxygen , thatís what makes our blood red . but in some sorts of crustaceans , crabs and lobsters , theyíre different they use copper . they use a compound called hemocyanin , itís a blue compound of copper . cyanine is some classical word for blue . so they really have blue blood . and these hemocyanin use two atoms of copper in each molecule to transport the oxygen around the body of the crab or lobster . but itís not nearly as good as haemoglobin , so if you start running after a crab or lobster it quickly gets tired compared to running after a rabbit or something like that , which can keep going faster than you can .
|
when you cut the metal you get this very nice , shiny , fresh surface coloured just like copper . this is a ball of copper , copper metal . as you might imagine itís a ball of metal so therefore it is quite dense and heavy .
|
the statue of liberty in new york is the largest copper statue in the world . if it is made of copper , why does it look blue-green in color ?
|
translator : andrea mcdonough reviewer : jessica ruby how big was that fish you caught ? this big ? this big ? this big ? without photographic evidence , there 's nothing that proves you caught a whopper , and that 's been true since the dawn of fishing . in fact , hundreds of years ago , long before photography could capture the moment , japanese fishermen invented their own way to record trophy catches . they called it gyotaku . gyotaku is the ancient art of printing fish that originated in japan as a way to record trophy catches prior to the modern day camera . gyo means fish and taku means impression . there are several different stories about how gyotaku came about , but it basically started with fishermen needing a way to record the species and size of the fish they caught over 100 years ago . fishermen took paper , ink , and brushes out to sea with them . they told stories of great adventures at sea . since the japanese revered certain fish , the fishermen would take a rubbing from these fish and release them . to make the rubbing , they would paint the fish with non-toxic sumi-e ink and print them on rice paper . this way they could be released or cleaned and sold at market . the first prints like this were for records only with no extra details . it was n't until the mid 1800 's that they began painting eye details and other embellishments onto the prints . one famous nobleman , lord sakai , was an avid fisherman , and , when he made a large catch , he wanted to preserve the memory of the large , red sea bream . to do so , he commissioned a fisherman to print his catch . after this , many fisherman would bring their gyotaku prints to lord sakai , and if he liked their work , he would hire them to print for him . many prints hung in the palace during the edo period . after this period , gyotaku was not as popular and began to fade away . today , gyotaku has become a popular art form , enjoyed by many . and the prints are said to bring good luck to the fishermen . but the art form is quite different than it used to be . most artists today learn on their own by trial and error . before the artist begins to print , the fish needs to be prepared for printing . first , the artist places the fish on a hollowed out surface . then the artist spreads the fins out and pins them down on the board to dry . they then clean the fish with water . when it comes time to print , there are two different methods . the indirect method begins with pasting moist fabric or paper onto the fish using rice paste . then , the artist uses a tompo , or a cotton ball covered in silk , to put ink on the fabric or paper to produce the print . this method requires more skill and great care needs to be taken when pulling the paper off the fish so the paper does n't tear . in the direct method , the artist paints directly on the fish , and then gently presses the moist fabric or paper into the fish . with both of these methods , no two prints are exactly alike , but both reveal dramatic images of the fish . for the final touch , the artist uses a chop , or a stamp , and signs their work , and can hold it up to say , `` the fish was exactly this big ! ''
|
after this period , gyotaku was not as popular and began to fade away . today , gyotaku has become a popular art form , enjoyed by many . and the prints are said to bring good luck to the fishermen .
|
today , what art forms resemble gyotaku ?
|
ok , so we take the top off . we add a match . the barking dog experiment was one of the most famous experiments and favourite experiments that was done by my former colleague , colonel b.d . shaw . so neil and i are preparing for one of my favourite reactions . itís called the barking dog reaction . this is a reaction which actually makes an element and weíre going to make some sulphur today . so the reactionís quite cool . in the barking dog experiment you have a mixture of the molecule carbon disulphide , cs2 . itís just like carbon dioxide butöwait a minute iímö so this is a test tube , a rather large test tube , of laughing gas , n2o , and weíre going to use this to make some sulphur . so i have a model here . so itís cs2 which has a carbon in the middle and sulphurs at either end . so it looks just like , in a model , as a molecule of co2 , but it has sulphur there and there . and this molecule , cs2 , will react with laughing gas , n2o . so where are we going to do this now ? in the dark somewhere . so essentially you are just using the laughing gas as a sort of oxygen to burn this molecule . what we are actually going to do is generate a lot of light . it used to be used as a flash , for cameras and for photography . what happens is you get a very bright emission of a sort of bluish purple light , which in the old days was used for taking photographs before people had flash-lamps on their cameras . they would set this off and it would give a great flash of light which could be used to take photographs . but because itís much slower than a flash it makes people really have quite a surprised look and this may well be why , in old photographs , people look so surprised because `` my god , this thing has gone off , whoosh ! '' so weíre on the hunt for a very dark place . in the tube , as the reaction takes place it generates heat . ok , so into the small lecture theatre which is vacant now . itís quite nice because we can turn all the lights off and make it a bit darker and see this reaction in its , sort of , best . so weíve managed to create a darker environment so we can really see the benefits from this chemistry , and neilís put some water in the bottom of the tube . and weíre going to put about 6-8 millilitres of carbon disulphide into this tube , and a good mix so you can be sure that we get all of that carbon disulphide going into the later phase so that itíll react really quite quickly with all of that oxygen , the n2o . as the flame goes down the tube it accelerates because the reactionís going faster and faster so it gives this great sort of ëwhoopí noise . now then , that was a really , really energetic reaction because the organic and the oxygen were all in the same phase and the reaction got a lot faster . the noise it made got a lot louder as it went down because of pressure . so what you can see in the tube here is actually the result or the aim of our chemical reaction today because we wanted to make some sulphur . so what weíve got here , coated on the inside of this tube , is a thin layer of polymeric sulphur . so you can see all this really quite nice sulphur coating the inside of the glass flask itself . now iím really fortunate because iím just going to go back to my office and prepare a lecture and leave neil to clean this . thanks . what are you doing mate ? well iíve just filled up my vessel with some oxygen . so this is liquid oxygen which we made for an earlier demonstration , and weíve just used it to drive off all of the non-combustible nitrogen form inside this glass vessel . well look at all that oxygen floating around inside the bottom of that flask , thatís really cool . all oscillating - a really nice experiment . yeah this is a really quite crazy jar . itís a small amount of sulphur , or ësuphurí , that weíve decanted out and unfortunately when we decanted it out we spelt the name wrong soö whoís responsible for that ? err , itís aövery old friend of mine and i couldnít possiblyögive you his identity as he would be really , really angry . wouldnít he , neil ? yeah iím saying nothing . and it wasnít neil . it wasnít me . so here weíve got a small amount of sulphur that we are going to put on the tip of this spoon . so you can see itís starting to melt . now with the top , so itís on fire and then weíll just drop it into the flask . and you can see that that sulphurís burning really intensely now , with a really quite beautiful flame . itís generating a lot of so2 , really smelly , which is why we are doing it inside this fume cupboard and you can see this really rich intense blue flame as that sulphur is burning in that excess oxygen in that atmosphere . ok so this is actually a sort of geological sample of sulphur . so you can see itís actually on the bottom , weíve actually got a rock and the sulphur crystals have actually formed on top of it . so actually , sulphur does occur naturally . i think itís been known since ancient times so , you know , when sermons are being delivered , fire and brimstone , was because hell is supposed to smell like sulphur , which is brimstone . but actually sulphur itself doesnít actually smell , but what you are smelling , the ësulphuryí smell , is actually oxidised material and hydrogen sulphide . well itís actually a mixture of sulphur and sand that was picked up by one of my colleagues on his honeymoon , though you see he was actually thinking about chemistry even on his honeymoon , though i donít think he told his wife that . i have a feeling but i could wrong that i bought this sample in oxfordshire where i used to live and i think itís actually from brazil , though i could be wrong . so as we are using up all the sulphur now the flame will die down until eventually it will go out . cool , there you go .
|
shaw . so neil and i are preparing for one of my favourite reactions . itís called the barking dog reaction .
|
sulfur exists as several allotropes , but which is the predominant one found in nature ?
|
translator : tom carter reviewer : bedirhan cinar it is the spring of 1787 . the revolutionary war has been over for only six years , and the young united states is still struggling in its infancy . uprisings , boundary disputes and the lack of a common vision all plague the newborn country . in an effort to steady this precarious ship , the confederation congress calls on states to send delegates to the grand convention , to begin on may 14 in philadelphia . the delegates must draft revisions to the articles of confederation , which would then be considered by the congress and approved by the states . under the terms of the articles , all 13 states had to agree to any changes . since the purpose of the convention is just to make recommendations , not everyone is excited about attending , and frankly , some think it 's a waste of time . as men from different parts of the country began to travel down dusty , rugged roads on the way to philadelphia , not all states send delegates . in fact , rhode island never even shows up . on may 14th , only 8 delegates -- not states , but individual delegates -- are present , so they wait . finally , on may 25th , the necessary quorum of seven states is acheived . in all , 55 delegates arrive in philadelphia over the course of the convention . they are all white males , property owners , and the average age is about 44 . some are slaveholders , some had signed the declaration of independence , [ james madison , roger sherman ] and almost all are well-educated . [ benjamin franklin ] picture the delegates , james madison and george washington among them , sitting in independence hall in hot , humid philadelphia . they 're all wearing the dress of the day : frock coats , high collars and thick pants . they vote to keep their discussions secret to encourage honest debate . but that means the windows are closed , and there is no air conditioning in 1787 , not even an electric fan . and they 'll sit in that sweltering heat , in those heavy clothes , for three months . shockingly , they all keep their vow of secrecy . that could never happen today , not even for an hour-long meeting . someone would share `` james madison thinks he 's so smart . keyword : articles are dead '' via social media , and the whole thing would be a disaster . but in 1787 , there are no leaks . not even a drip that hints at what they are doing . and what they are doing is nothing short of overthrowing the very government that sent them there . within a few days , with only a seven-state quorum , and only six of those states agreeing , a handful of men change the course of history . they vote to get rid of the articles of confederation , and write a new , more nationalistic document that becomes our constitution . the risk is immense . everyone on the outside assumes they were working on recommended revisions to the articles . it 's an incredible gamble , and even when the convention presents the signed constitution on september 17th , not all delegates endorse it . the country will argue and debate for two more years before the document is adopted by the required nine out of 13 states . but instead of punishing them for their deception , today we celebrate the wisdom and vision of those men in philadelphia .
|
shockingly , they all keep their vow of secrecy . that could never happen today , not even for an hour-long meeting . someone would share `` james madison thinks he 's so smart .
|
the document drafted by the convention delegates did not originally apply to women or people of color but , through amendments and supreme court decisions , has evolved to include many such groups . how do you think the framers would react to these changes if you could speak with them today ?
|
most people recognize his name and know that he is famous for having said something , but considering the long-lasting impact his teachings have had on the world , very few people know who confucius really was , what he really said , and why . amid the chaos of 6th century bce china , where warring states fought endlessly among themselves for supremacy , and rulers were frequently assassinated , sometimes by their own relatives , confucius exemplified benevolence and integrity , and through his teaching , became one of china 's greatest philosophers . born to a nobleman but raised in poverty from a very young age following the untimely death of his father , confucius developed what would become a lifelong sympathy for the suffering of the common people . barely supporting his mother and disabled brother as a herder and account keeper at a granary , and with other odd jobs , it was only with the help of a wealthy friend that confucius was able to study at the royal archives , where his world view would be formed . though the ancient texts there were regarded by some as irrelevant relics of the past , confucius was inspired by them . through study and reflection , confucius came to believe that human character is formed in the family and by education in ritual , literature , and history . a person cultivated in this way works to help others , guiding them by moral inspiration rather than brute force . to put his philosophy into practice , confucius became an advisor to the ruler of his home state of lu . but after another state sent lu 's ruler a troop of dancing girls as a present and the ruler ignored his duties while enjoying the girls in private , confucius resigned in disgust . he then spent the next few years traveling from state to state , trying to find a worthy ruler to serve , while holding fast to his principles . it was n't easy . in accordance with his philosophy , and contrary to the practice of the time , confucius dissuaded rulers from relying on harsh punishments and military power to govern their lands because he believed that a good ruler inspires others to spontaneously follow him by virtue of his ethical charisma . confucius also believed that because the love and respect we learn in the family are fundamental to all other virtues , personal duties to family sometimes supersede obligations to the state . so when one duke bragged that his subjects were so upright that a son testified against his own father when his father stole a sheep , confucius informed the duke that genuinely upright fathers and sons protected one another . during his travels , confucius almost starved , he was briefly imprisoned , and his life was threatened at several points . but he was not bitter . confucius had faith that heaven had a plan for the world , and he taught that a virtuous person could always find joy in learning and music . failing to find the ruler he sought , confucius returned to lu and became a teacher and philosopher so influential , that he helped shaped chinese culture and we recognize his name worldwide , even today . for the disciples of confucius , he was the living embodiment of a sage who leads others through his virtue , and they recorded his sayings , which eventually were edited into a book we know in english as `` the analects . '' today , millions of people worldwide adhere to the principles of confucianism , and though the precise meaning of his words has been debated for millennia , when asked to summarize his teachings in a single phrase , confucius himself said , `` do not inflict upon others that which you yourself would not want . '' 2,500 years later , it 's still sage advice .
|
during his travels , confucius almost starved , he was briefly imprisoned , and his life was threatened at several points . but he was not bitter . confucius had faith that heaven had a plan for the world , and he taught that a virtuous person could always find joy in learning and music . failing to find the ruler he sought , confucius returned to lu and became a teacher and philosopher so influential , that he helped shaped chinese culture and we recognize his name worldwide , even today .
|
according to confucius , how should a virtuous person avoid becoming frustrated or bitter in the face of adversity ?
|
studies have shown that taking vitamins is good for your health and bad for your health . that newly discovered herb can improve your memory or destroy your liver . headlines proclaim a promising new cancer treatment and never mention it again . on a daily basis , we are bombarded with attention-grabbing news , backed up by scientific studies , but what are these studies ? how are they performed ? and how do we know whether they 're reliable ? when it comes to dietary or medical information , the first thing to remember is that while studies on animals or individual cells can point the way towards further research , the only way to know how something will affect humans is through a study involving human subjects . and when it comes to human studies , the scientific gold standard is the randomized clinical trial , or rct . the key to rcts is that the subjects are randomly assigned to their study groups . they are often blinded to make them more rigorous . this process attempts to ensure that the only difference between the groups is the one the researchers are attempting to study . for example , when testing a new headache medication , a large pool of people with headaches would be randomly divided into two groups , one receiving the medication and another receiving a placebo . with proper randomization , the only significant overall difference between the two groups will be whether or not they received the medication , rather than other differences that could affect results . randomized clinical trials are incredible tools , and , in fact , the us food and drug administration often requires at least two to be conducted before a new drug can be marketed . but the problem is that an rct is not possible in many cases , either because it 's not practical or would require too many volunteers . in such cases , scientists use an epidemiological study , which simply observes people going about their usual behavior , rather than randomly assigning active participants to control invariable groups . let 's say we wanted to study whether an herbal ingredient on the market causes nausea . rather than deliberately giving people something that might make them nauseated , we would find those who already take the ingredient in their everyday lives . this group is called the cohort . we would also need a comparison group of people who do not have exposure to the ingredient . and we would then compare statistics . if the rate of nausea is higher in the herbal cohort , it suggests an association between the herbal supplement and nausea . epidemiological studies are great tools to study the health effects of almost anything , without directly interfering in people 's lives or assigning them to potentially dangerous exposures . so , why ca n't we rely on these studies to establish causal relationships between substances and their effects on health ? the problem is that even the best conducted epidemiological studies have inherent flaws . precisely because the test subjects are not randomly assigned to their groups . for example , if the cohort in our herbal study consisted of people who took the supplement for health reasons , they may have already had higher rates of nausea than the other people in the sample . or the cohort group could 've been composed of people who shop at health food stores and have different diets or better access to healthcare . these factors that can affect results , in addition to the factor being studied , are known as confounding variables . these two major pitfalls , combined with more general dangers , such as conflicts of interest or selective use of data , can make the findings of any particular epidemiological study suspect , and a good study must go out of its way to prove that its authors have taken steps to eliminate these types of errors . but even when this has been done , the very nature of epidemiological studies , which examine differences between preexisting groups , rather than deliberately inducing changes within the same individuals , means that a single study can only demonstrate a correlation between a substance and a health outcome , rather than a true cause and effect relationship . at the end of the day , epidemiological studies have served as excellent guides to public health , alerting us to critical health hazards , such as smoking , asbestos , lead , and many more . but these were demonstrated through multiple , well-conducted epidemiological studies , all pointing in the same direction . so , the next time you see a headline about a new miracle cure or the terrible danger posed by an everyday substance , try to learn more about the original study and the limitations inherent in any epidemiological study or clinical trial before jumping to conclusions .
|
if the rate of nausea is higher in the herbal cohort , it suggests an association between the herbal supplement and nausea . epidemiological studies are great tools to study the health effects of almost anything , without directly interfering in people 's lives or assigning them to potentially dangerous exposures . so , why ca n't we rely on these studies to establish causal relationships between substances and their effects on health ?
|
give some examples where epidemiological studies have helped scientists understand the risks of particular agents or exposures .
|
a famous ancient greek once said , `` give me a place to stand , and i shall move the earth . '' but this was n't some wizard claiming to perform impossible feats . it was the mathematician archimedes describing the fundamental principle behind the lever . the idea of a person moving such a huge mass on their own might sound like magic , but chances are you 've seen it in your everyday life . one of the best examples is something you might recognize from a childhood playground : a teeter-totter , or seesaw . let 's say you and a friend decide to hop on . if you both weigh about the same , you can totter back and forth pretty easily . but what happens if your friend weighs more ? suddenly , you 're stuck up in the air . fortunately , you probably know what to do . just move back on the seesaw , and down you go . this may seem simple and intuitive , but what you 're actually doing is using a lever to lift a weight that would otherwise be too heavy . this lever is one type of what we call simple machines , basic devices that reduce the amount of energy required for a task by cleverly applying the basic laws of physics . let 's take a look at how it works . every lever consists of three main components : the effort arm , the resistance arm , and the fulcrum . in this case , your weight is the effort force , while your friend 's weight provides the resistance force . what archimedes learned was that there is an important relationship between the magnitudes of these forces and their distances from the fulcrum . the lever is balanced when the product of the effort force and the length of the effort arm equals the product of the resistance force and the length of the resistance arm . this relies on one of the basic laws of physics , which states that work measured in joules is equal to force applied over a distance . a lever ca n't reduce the amount of work needed to lift something , but it does give you a trade-off . increase the distance and you can apply less force . rather than trying to lift an object directly , the lever makes the job easier by dispersing its weight across the entire length of the effort and resistance arms . so if your friend weighs twice as much as you , you 'd need to sit twice as far from the center as him in order to lift him . by the same token , his little sister , whose weight is only a quarter of yours , could lift you by sitting four times as far as you . seesaws may be fun , but the implications and possible uses of levers get much more impressive than that . with a big enough lever , you can lift some pretty heavy things . a person weighing 150 pounds , or 68 kilograms , could use a lever just 3.7 meters long to balance a smart car , or a ten meter lever to lift a 2.5 ton stone block , like the ones used to build the pyramids . if you wanted to lift the eiffel tower , your lever would have to be a bit longer , about 40.6 kilometers . and what about archimedes ' famous boast ? sure , it 's hypothetically possible . the earth weighs 6 x 10^24 kilograms , and the moon that 's about 384,400 kilometers away would make a great fulcrum . so all you 'd need to lift the earth is a lever with a length of about a quadrillion light years , 1.5 billion times the distance to the andromeda galaxy . and of course a place to stand so you can use it . so for such a simple machine , the lever is capable of some pretty amazing things . and the basic elements of levers and other simple machines are found all around us in the various instruments and tools that we , and even some other animals , use to increase our chances of survival , or just make our lives easier . after all , it 's the mathematical principles behind these devices that make the world go round .
|
sure , it 's hypothetically possible . the earth weighs 6 x 10^24 kilograms , and the moon that 's about 384,400 kilometers away would make a great fulcrum . so all you 'd need to lift the earth is a lever with a length of about a quadrillion light years , 1.5 billion times the distance to the andromeda galaxy .
|
create a situation that would require one person to sit 6 meters away from the fulcrum of a teeter-totter while the other person sit 5 meters away .
|
translator : ido dekkers reviewer : emma gon ( music ) every movie you 've ever seen , every tv show , every magazine , every time you surf the internet , you 're absorbing information , a bit like a sponge absorbs water . the words on the screen , the images , the colors , the sounds , the angle of the camera , every detail is designed to make you think , act or feel a certain way . your brain is subconsciously decoding images and sounds , and just by being alive today , by interacting with and reading all these different types of media , you 're already an expert at decoding and understanding these hidden messages . a set of codes and conventions that work together to make you feel happy , angry , afraid , excited . to make you want to buy a particular product -- a refreshing drink , a new phone . to style your hair a certain way . to cheer for the hero or boo the villain . welcome to the family tree of technical codes . so what constitutes a code ? first of all , it has to be recognized by all who read it . imagine a busy city where motorists do n't know how to read the traffic signals . we all have to know red equals stop , green means go , for the system to work . otherwise it would be chaos . secondly , codes are made meaningful by their context . we ca n't fully interpret or decipher a code until we see how it relates to other signs and symbols . look at these two intersecting lines . without any context , things around the code to help you understand or make meaning from it , it 's hard to know exactly what these lines represent . they could be a cross , symbolizing religion , an add sign , symbolizing a mathematical concept , the letter t from the alphabet , or they could just be two lines intersecting . if we add a crescent moon shape , and a circle with a line on it in front , the two lines now have a context , a relationship to their surroundings , and are magically revealed as the letter t. by adding additional information around the code , we 've changed its context , and therefore given it a concrete meaning . let 's meet the family . technical codes , senior has three sons : symbolic codes , written codes and technical codes , junior . symbolic codes has three sons : symbolic color , symbolic objects and symbolic animals . this branch of the family is all about representation . red represents hot or stop or danger , depending on its context . so if you see a red light above a yellow and a green light on a pole above the road , you know by this context that the light represents stop . written codes has three sons : you and only you , buzzwords and catchphrase . these guys are all about saying a lot with a little , or planting a word in your subconscious that triggers a response whenever you hear or read it . have you noticed how many times i 've said the word `` you ? '' you should feel like it 's directed specifically at you , and only you , that it 's addressing your needs and desire to learn about your world . if i tell you that all the cool , fresh and hip people are buying a new drink or wearing a particular brand , the buzzwords `` new , '' `` fresh '' or `` free '' make the product seem more interesting and appealing . if i wrap that product or idea in a simple phrase that 's easy to remember and becomes part of your everyday speech , then every time you hear or say those few words , your brain connects them to the product . so just do it , think different , and enjoy the power of the catchphrase . and technical codes , junior has three sons : camera angles , framing and lighting . for these boys , it 's all about how the camera is placed , how objects , people and places are shot , and what we see on screen -- or just as importantly , what we do n't see . when the camera is placed high above the subject , it makes you look small , insignificant and powerless . and the reverse is also true , when the camera is below . so is this video trying to manipulate you to buy something ? yes , an idea . the idea that understanding the relationship between technical codes and the role they play in shaping your understanding of the world around us through the media we consume is fun and interesting . is it trying to make you feel a certain way ? absolutely . every image , every word , has been carefully crafted to work together to make you feel positive about the idea that you need to be educated to engage with what you read , watch and listen to in movies , tv shows , magazines and on the internet . by understanding these codes , and how they work together to subconsciously change the way you think , feel and act towards products and ideas , you 'll be aware of these techniques and able to identify their impact on you . one of the most powerful advertising mediums in the world is word of mouth . if you 've ever recommended a product or movie , a service , or even a video online , then you 've played your part in passing the message . so soak all this information up . recognize how the family tree of technical codes works on you , and those around you , to make an impact find excellent examples , and spread the word .
|
you should feel like it 's directed specifically at you , and only you , that it 's addressing your needs and desire to learn about your world . if i tell you that all the cool , fresh and hip people are buying a new drink or wearing a particular brand , the buzzwords `` new , '' `` fresh '' or `` free '' make the product seem more interesting and appealing . if i wrap that product or idea in a simple phrase that 's easy to remember and becomes part of your everyday speech , then every time you hear or say those few words , your brain connects them to the product .
|
what 's your favorite brand ? can you attribute your fondness to the advertising about the brand ?
|
when i was first learning to meditate , the instruction was to simply pay attention to my breath , and when my mind wandered , to bring it back . sounded simple enough . yet i 'd sit on these silent retreats , sweating through t-shirts in the middle of winter . i 'd take naps every chance i got because it was really hard work . actually , it was exhausting . the instruction was simple enough but i was missing something really important . so why is it so hard to pay attention ? well , studies show that even when we 're really trying to pay attention to something -- like maybe this talk -- at some point , about half of us will drift off into a daydream , or have this urge to check our twitter feed . so what 's going on here ? it turns out that we 're fighting one of the most evolutionarily-conserved learning processes currently known in science , one that 's conserved back to the most basic nervous systems known to man . this reward-based learning process is called positive and negative reinforcement , and basically goes like this . we see some food that looks good , our brain says , `` calories ! ... survival ! '' we eat the food , we taste it -- it tastes good . and especially with sugar , our bodies send a signal to our brain that says , `` remember what you 're eating and where you found it . '' we lay down this context-dependent memory and learn to repeat the process next time . see food , eat food , feel good , repeat . trigger , behavior , reward . simple , right ? well , after a while , our creative brains say , `` you know what ? you can use this for more than just remembering where food is . you know , next time you feel bad , why do n't you try eating something good so you 'll feel better ? '' we thank our brains for the great idea , try this and quickly learn that if we eat chocolate or ice cream when we 're mad or sad , we feel better . same process , just a different trigger . instead of this hunger signal coming from our stomach , this emotional signal -- feeling sad -- triggers that urge to eat . maybe in our teenage years , we were a nerd at school , and we see those rebel kids outside smoking and we think , `` hey , i want to be cool . '' so we start smoking . the marlboro man was n't a dork , and that was no accident . see cool , smoke to be cool , feel good . repeat . trigger , behavior , reward . and each time we do this , we learn to repeat the process and it becomes a habit . so later , feeling stressed out triggers that urge to smoke a cigarette or to eat something sweet . now , with these same brain processes , we 've gone from learning to survive to literally killing ourselves with these habits . obesity and smoking are among the leading preventable causes of morbidity and mortality in the world . so back to my breath . what if instead of fighting our brains , or trying to force ourselves to pay attention , we instead tapped into this natural , reward-based learning process ... but added a twist ? what if instead we just got really curious about what was happening in our momentary experience ? i 'll give you an example . in my lab , we studied whether mindfulness training could help people quit smoking . now , just like trying to force myself to pay attention to my breath , they could try to force themselves to quit smoking . and the majority of them had tried this before and failed -- on average , six times . now , with mindfulness training , we dropped the bit about forcing and instead focused on being curious . in fact , we even told them to smoke . what ? yeah , we said , `` go ahead and smoke , just be really curious about what it 's like when you do . '' and what did they notice ? well here 's an example from one of our smokers . she said , `` mindful smoking : smells like stinky cheese and tastes like chemicals , yuck ! '' now , she knew , cognitively that smoking was bad for her , that 's why she joined our program . what she discovered just by being curiously aware when she smoked was that smoking tastes like shit . ( laughter ) now , she moved from knowledge to wisdom . she moved from knowing in her head that smoking was bad for her to knowing it in her bones , and the spell of smoking was broken . she started to become disenchanted with her behavior . now , the prefrontal cortex , that youngest part of our brain from an evolutionary perspective , it understands on an intellectual level that we should n't smoke . and it tries its hardest to help us change our behavior , to help us stop smoking , to help us stop eating that second , that third , that fourth cookie . we call this cognitive control . we 're using cognition to control our behavior . unfortunately , this is also the first part of our brain that goes offline when we get stressed out , which is n't that helpful . now , we can all relate to this in our own experience . we 're much more likely to do things like yell at our spouse or kids when we 're stressed out or tired , even though we know it 's not going to be helpful . we just ca n't help ourselves . when the prefrontal cortex goes offline , we fall back into our old habits , which is why this disenchantment is so important . seeing what we get from our habits helps us understand them at a deeper level -- to know it in our bones so we do n't have to force ourselves to hold back or restrain ourselves from behavior . we 're just less interested in doing it in the first place . and this is what mindfulness is all about : seeing really clearly what we get when we get caught up in our behaviors , becoming disenchanted on a visceral level and from this disenchanted stance , naturally letting go . this is n't to say that , poof , magically we quit smoking . but over time , as we learn to see more and more clearly the results of our actions , we let go of old habits and form new ones . the paradox here is that mindfulness is just about being really interested in getting close and personal with what 's actually happening in our bodies and minds from moment to moment . this willingness to turn toward our experience rather than trying to make unpleasant cravings go away as quickly as possible . and this willingness to turn toward our experience is supported by curiosity , which is naturally rewarding . what does curiosity feel like ? it feels good . and what happens when we get curious ? we start to notice that cravings are simply made up of body sensations -- oh , there 's tightness , there 's tension , there 's restlessness -- and that these body sensations come and go . these are bite-size pieces of experiences that we can manage from moment to moment rather than getting clobbered by this huge , scary craving that we choke on . in other words , when we get curious , we step out of our old , fear-based , reactive habit patterns , and we step into being . we become this inner scientist where we 're eagerly awaiting that next data point . now , this might sound too simplistic to affect behavior . but in one study , we found that mindfulness training was twice as good as gold standard therapy at helping people quit smoking . so it actually works . and when we studied the brains of experienced meditators , we found that parts of a neural network of self-referential processing called the default mode network were at play . now , one current hypothesis is that a region of this network , called the posterior cingulate cortex , is activated not necessarily by craving itself but when we get caught up in it , when we get sucked in , and it takes us for a ride . in contrast , when we let go -- step out of the process just by being curiously aware of what 's happening -- this same brain region quiets down . now we 're testing app and online-based mindfulness training programs that target these core mechanisms and , ironically , use the same technology that 's driving us to distraction to help us step out of our unhealthy habit patterns of smoking , of stress eating and other addictive behaviors . now , remember that bit about context-dependent memory ? we can deliver these tools to peoples ' fingertips in the contexts that matter most . so we can help them tap into their inherent capacity to be curiously aware right when that urge to smoke or stress eat or whatever arises . so if you do n't smoke or stress eat , maybe the next time you feel this urge to check your email when you 're bored , or you 're trying to distract yourself from work , or maybe to compulsively respond to that text message when you 're driving , see if you can tap into this natural capacity , just be curiously aware of what 's happening in your body and mind in that moment . it will just be another chance to perpetuate one of our endless and exhaustive habit loops ... or step out of it . instead of see text message , compulsively text back , feel a little bit better -- notice the urge , get curious , feel the joy of letting go and repeat . thank you . ( applause )
|
she started to become disenchanted with her behavior . now , the prefrontal cortex , that youngest part of our brain from an evolutionary perspective , it understands on an intellectual level that we should n't smoke . and it tries its hardest to help us change our behavior , to help us stop smoking , to help us stop eating that second , that third , that fourth cookie .
|
which part of your brain knows it ’ s bad to smoke ?
|
albert einstein played a key role in launching quantum mechanics through his theory of the photoelectric effect but remained deeply bothered by its philosophical implications . and though most of us still remember him for deriving e=mc^2 , his last great contribution to physics was actually a 1935 paper , coauthored with his young colleagues boris podolsky and nathan rosen . regarded as an odd philosophical footnote well into the 1980s , this epr paper has recently become central to a new understanding of quantum physics , with its description of a strange phenomenon now known as entangled states . the paper begins by considering a source that spits out pairs of particles , each with two measurable properties . each of these measurements has two possible results of equal probability . let 's say zero or one for the first property , and a or b for the second . once a measurement is performed , subsequent measurements of the same property in the same particle will yield the same result . the strange implication of this scenario is not only that the state of a single particle is indeterminate until it 's measured , but that the measurement then determines the state . what 's more , the measurements affect each other . if you measure a particle as being in state 1 , and follow it up with the second type of measurement , you 'll have a 50 % chance of getting either a or b , but if you then repeat the first measurement , you 'll have a a 50 % chance of getting zero even though the particle had already been measured at one . so switching the property being measured scrambles the original result , allowing for a new , random value . things get even stranger when you look at both particles . each of the particles will produce random results , but if you compare the two , you will find that they are always perfectly correlated . for example , if both particles are measured at zero , the relationship will always hold . the states of the two are entangled . measuring one will tell you the other with absolute certainty . but this entanglement seems to defy einstein 's famous theory of relativity because there is nothing to limit the distance between particles . if you measure one in new york at noon , and the other in san francisco a nanosecond later , they still give exactly the same result . but if the measurement does determine the value , then this would require one particle sending some sort of signal to the other at 13,000,000 times the speed of light , which according to relativity , is impossible . for this reason , einstein dismissed entanglement as `` spuckafte ferwirklung , '' or spooky action at a distance . he decided that quantum mechanics must be incomplete , a mere approximation of a deeper reality in which both particles have predetermined states that are hidden from us . supporters of orthodox quantum theory lead by niels bohr maintained that quantum states really are fundamentally indeterminate , and entanglement allows the state of one particle to depend on that of its distant partner . for 30 years , physics remained at an impasse , until john bell figured out that the key to testing the epr argument was to look at cases involving different measurements on the two particles . the local hidden variable theories favored by einstein , podolsky and rosen , strictly limited how often you could get results like 1a or b0 because the outcomes would have to be defined in advanced . bell showed that the purely quantum approach , where the state is truly indeterminate until measured , has different limits and predicts mixed measurement results that are impossible in the predetermined scenario . once bell had worked out how to test the epr argument , physicists went out and did it . beginning with john clauster in the 70s and alain aspect in the early 80s , dozens of experiments have tested the epr prediction , and all have found the same thing : quantum mechanics is correct . the correlations between the indeterminate states of entangled particles are real and can not be explained by any deeper variable . the epr paper turned out to be wrong but brilliantly so . by leading physicists to think deeply about the foundations of quantum physics , it led to further elaboration of the theory and helped launch research into subjects like quantum information , now a thriving field with the potential to develop computers of unparalleled power . unfortunately , the randomness of the measured results prevents science fiction scenarios , like using entangled particles to send messages faster than light . so relativity is safe , for now . but the quantum universe is far stranger than einstein wanted to believe .
|
by leading physicists to think deeply about the foundations of quantum physics , it led to further elaboration of the theory and helped launch research into subjects like quantum information , now a thriving field with the potential to develop computers of unparalleled power . unfortunately , the randomness of the measured results prevents science fiction scenarios , like using entangled particles to send messages faster than light . so relativity is safe , for now .
|
if two people ( traditionally called “ alice ” and “ bob ” ) share a bunch of entangled particles , it might seem like this would let them send messages faster than light , since whenever alice measures her particle in state “ 0 , ” bob also finds his in state “ 0. ” explain how even though the correlation between states is perfect , this is not a tool for communicating faster than light .
|
language is an essential part of our lives that we often take for granted . with it , we can communicate our thoughts and feelings , lose ourselves in novels , send text messages , and greet friends . it 's hard to imagine being unable to turn thoughts into words . but if the delicate web of language networks in your brain became disrupted by stroke , illness , or trauma , you could find yourself truly at a loss for words . this disorder , called aphasia , can impair all aspects of communication . people who have aphasia remain as intelligent as ever . they know what they want to say , but ca n't always get their words to come out correctly . they may unintentionally use substitutions called paraphasias , switching related words , like saying `` dog '' for `` cat , '' or words that sound similar , such as `` house '' for `` horse . '' sometimes , their words may even be unrecognizable . there are several types of aphasia grouped into two categories : fluent , or receptive , aphasia and non-fluent , or expressive , aphasia . people with fluent aphasia may have normal vocal inflection but use words that lack meaning . they have difficulty comprehending the speech of others and are frequently unable to recognize their own speech errors . people with non-fluent aphasia , on the other hand , may have good comprehension but will experience long hesitations between words and make grammatical errors . we all have that tip-of-the-tongue feeling from time to time when we ca n't think of a word , but having aphasia can make it hard to name simple , everyday objects . even reading and writing can be difficult and frustrating . so how does this language loss happen ? the human brain has two hemispheres . in most people , the left hemisphere governs language . we know this because in 1861 , the physician paul broca studied a patient who lost the ability to use all but a single word , `` tan . '' during a postmortem study of that patient 's brain , broca discovered a large lesion in the left hemisphere now known as broca 's area . scientists today believe that broca 's area is responsible in part for naming objects and coordinating the muscles involved in speech . behind broca 's area is wernicke 's area near the auditory cortex . that 's where the brain attaches meaning to speech sounds . damage to wernicke 's area impairs the brain 's ability to comprehend language . aphasia is caused by injury to one or both of these specialized language areas . fortunately , there are other areas of the brain which support these language centers and can assist with communication . even brain areas that control movement are connected to language . fmri studies found that when we hear action words , like `` run '' or `` dance , '' parts of the brain responsible for movement light up as if the body was actually running or dancing . our other hemisphere contributes to language , too , enhancing the rhythm and intonation of our speech . these non-language areas sometimes assist people with aphasia when communication is difficult . so how common is aphasia ? approximately 1 million people in the u.s. alone have it , with an estimated 80,000 new cases per year . about one-third of stroke survivors suffer from aphasia making it more prevalent than parkinson 's disease or multiple sclerosis , yet less widely known . there is one rare form of aphasia called primary progressive aphasia , or ppa , which is not caused by stroke or brain injury , but is actually a form of dementia in which language loss is the first symptom . the goal in treating ppa is to maintain language function for as long as possible before other symptoms of dementia eventually occur . however , when aphasia is acquired from a stroke or brain trauma , language improvement may be achieved through speech therapy . our brain 's ability to repair itself , known as brain plasticity , permits areas surrounding a brain lesion to take over some functions during the recovery process . scientists have been conducting experiments using new forms of technology , which they believe may encourage brain plasticity in people with aphasia . meanwhile , many people with aphasia remain isolated , afraid that others wo n't understand them or give them extra time to speak . by offering them the time and flexibility to communicate in whatever way they can , you can help open the door to language again , moving beyond the limitations of aphasia .
|
sometimes , their words may even be unrecognizable . there are several types of aphasia grouped into two categories : fluent , or receptive , aphasia and non-fluent , or expressive , aphasia . people with fluent aphasia may have normal vocal inflection but use words that lack meaning .
|
there are many types of aphasia , broadly grouped into two categories : fluent and non-fluent . what are the main differences between them ?
|
translator : bedirhan cinar why do we cringe when we hear `` shakespeare ? '' if you ask me , it 's usually because of his words . all those thines and thous and therefores and wherefore-art-thous can be more than a little annoying . but you have to wonder , why is he so popular ? why have his plays been made and remade more than any other playwright ? it 's because of his words . back in the late 1500s and early 1600s , that was the best tool that a person had , and there was a lot to talk about . however , most of it was pretty depressing . you know , with the black plague and all . shakespeare does use a lot of words . one of his most impressive accomplishments is his use of insults . they would unify the entire audience ; and no matter where you sat , you could laugh at what was going on onstage . words , specifically dialogue in a drama setting , are used for many different reasons : to set the mood of the scene , to give some more atmosphere to the setting , and to develop relationships between characters . insults do this in a very short and sharp way . let 's first go to `` hamlet . '' right before this dialogue , polonius is the father of ophelia , who is in love with prince hamlet . king claudius is trying to figure out why prince hamlet is acting so crazy since the king married prince hamlet 's mother . polonius offers to use his daughter to get information from prince hamlet . then we go into act ii scene 2 . polonius : `` do you know me , my lord ? '' hamlet : `` excellent well . you 're a fishmonger . '' polonius : `` not i , my lord . '' hamlet : `` then i would you were so honest a man . '' now , even if you did not know what `` fishmonger '' meant , you can use some contextual clues . one : polonius reacted in a negative way , so it must be bad . two : fish smell bad , so it must be bad . and three : `` monger '' just does n't sound like a good word . so from not even knowing the meaning , you 're beginning to construct some characterization of the relationship between hamlet and polonius , which was not good . but if you dig some more , `` fishmonger '' means a broker of some type , and in this setting , would mean like a pimp , like polonius is brokering out his daughter for money , which he is doing for the king 's favor . this allows you to see that hamlet is not as crazy as he 's claiming to be , and intensifies the animosity between these two characters . want another example ? `` romeo and juliet '' has some of the best insults of any of shakespeare 's plays . it 's a play about two gangs , and the star-crossed lovers that take their own lives . well , with any fisticuffs you know that there is some serious smack talk going on . and you are not disappointed . in act i scene 1 , right from the get-go we are shown the level of distrust and hatred the members of the two families , the capulets and montagues , meet . gregory : `` i will frown as i pass by , and let them take it as they list . '' sampson : `` nay , as they dare , i will bite my thumb at them , which is a disgrace to them , if they bear it . '' enter abraham and balthasar . abraham : `` do you bite your thumb at us , sir ? '' sampson : `` i do bite my thumb , sir . '' abraham : `` do you bite your thumb at us , sir ? '' okay , so how does this development help us understand mood or character ? well , let 's break it down to the insult . biting your thumb today may not seem like a big deal , but sampson says it is an insult to them . if they take it so , it must have been one . this begins to show us the level of animosity between even the men who work for the two houses . and you normally would not do anything to someone unless you wanted to provoke them into a fight , which is exactly what 's about to happen . looking deeper , biting your thumb in the time in which the play was written is like giving someone the finger today . a pretty strong feeling comes with that , so we now are beginning to feel the tension in the scene . later on in the scene , tybalt , from the house of the capulets , lays a good one on benvolio from the house of the montagues . tybalt : `` what , art thou drawn among these heartless hinds ? turn thee , benvolio , and look upon thy death . '' benvolio : `` i do but keep the peace ; put up thy sword , or manage it to part these men with me . '' tybalt : `` what , drawn and talk of peace ! i hate the word , as i hate hell , all montagues , and thee . have at thee , coward ! '' okay , heartless hinds . we know that once again , it 's not a good thing . both families hate each other , and this is just adding fuel to the fire . but just how bad is this stinger ? a heartless hind is a coward , and calling someone that in front of his own men , and the rival family , means there 's going to be a fight . tybalt basically calls out benvolio , and in order to keep his honor , benvolio has to fight . this dialogue gives us a good look at the characterization between these two characters . tybalt thinks that the montagues are nothing but cowardly dogs , and has no respect for them . once again , adding dramatic tension to the scene . okay , now here 's a spoiler alert . tybalt 's hotheadedness and severe hatred of the montagues is what we literature people call his hamartia , or what causes his downfall . oh , yes . he goes down at the hands of romeo . so when you 're looking at shakespeare , stop and look at the words , because they really are trying to tell you something .
|
you know , with the black plague and all . shakespeare does use a lot of words . one of his most impressive accomplishments is his use of insults .
|
how do you think audience reactions to shakespeare 's work has changed over the years ? how have the demographics of his audiences changed over time ?
|
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 !
|
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 .
|
can you design a 3-course meal with no added sugar ? what would you put on the plate ?
|
earthquakes have always been a terrifying phenomenon , and they 've become more deadly as our cities have grown , with collapsing buildings posing one of the largest risks . why do buildings collapse in an earthquake , and how can it be prevented ? if you 've watched a lot of disaster films , you might have the idea that building collapse is caused directly by the ground beneath them shaking violently , or even splitting apart . but that 's not really how it works . for one thing , most buildings are not located right on a fault line , and the shifting tectonic plates go much deeper than building foundations . so what 's actually going on ? in fact , the reality of earthquakes and their effect on buildings is a bit more complicated . to make sense of it , architects and engineers use models , like a two-dimensional array of lines representing columns and beams , or a single line lollipop with circles representing the building 's mass . even when simplified to this degree , these models can be quite useful , as predicting a building 's response to an earthquake is primarily a matter of physics . most collapses that occur during earthquakes are n't actually caused by the earthquake itself . instead , when the ground moves beneath a building , it displaces the foundation and lower levels , sending shock waves through the rest of the structure and causing it to vibrate back and forth . the strength of this oscillation depends on two main factors : the building 's mass , which is concentrated at the bottom , and its stiffness , which is the force required to cause a certain amount of displacement . along with the building 's material type and the shape of its columns , stiffness is largely a matter of height . shorter buildings tend to be stiffer and shift less , while taller buildings are more flexible . you might think that the solution is to build shorter buildlings so that they shift as little as possible . but the 1985 mexico city earthquake is a good example of why that 's not the case . durng the quake , many buildings between six and fifteen stories tall collapsed . what 's strange is that while shorter buildings nearby did keep standing , buildings taller than fifteen stories were also less damaged , and the midsized buildings that collapsed were observed shaking far more violently than the earthquake itself . how is that possible ? the answer has to do with something known as natural frequency . in an oscillating system , the frequency is how many back and forth movement cycles occur within a second . this is the inverse of the period , which is how many seconds it takes to complete one cycle . and a building 's natural frequency , determined by its mass and stiffness , is the frequency that its vibrations will tend to cluster around . increasing a building 's mass slows down the rate at which it naturally vibrates , while increasing stiffness makes it vibrate faster . so in the equation representing their relationship , stiffness and natural frequency are proportional to one another , while mass and natural frequency are inversely proportional . what happened in mexico city was an effect called resonance , where the frequency of the earthquake 's seismic waves happen to match the natural frequency of the midsized buildings . like a well-timed push on a swingset , each additional seismic wave amplified the building 's vibration in its current direction , causing it to swing even further back , and so on , eventually reaching a far greater extent than the initial displacement . today , engineers work with geologists and seismologists to predict the frequency of earthquake motions at building sites in order to prevent resonance-induced collapses , taking into account factors such as soil type and fault type , as well as data from previous quakes . low frequencies of motion will cause more damage to taller and more flexible buildings , while high frequencies of motion pose more threat to structures that are shorter and stiffer . engineers have also devised ways to abosrb shocks and limit deformation using innovative systems . base isolation uses flexible layers to isolate the foundation 's displacement from the rest of the building , while tuned mass damper systems cancel out resonance by oscillating out of phase with the natural frequency to reduce vibrations . in the end , it 's not the sturdiest buildings that will remain standing but the smartest ones .
|
increasing a building 's mass slows down the rate at which it naturally vibrates , while increasing stiffness makes it vibrate faster . so in the equation representing their relationship , stiffness and natural frequency are proportional to one another , while mass and natural frequency are inversely proportional . what happened in mexico city was an effect called resonance , where the frequency of the earthquake 's seismic waves happen to match the natural frequency of the midsized buildings . like a well-timed push on a swingset , each additional seismic wave amplified the building 's vibration in its current direction , causing it to swing even further back , and so on , eventually reaching a far greater extent than the initial displacement .
|
structural engineers consult with geologists to help predict the expected frequency of earthquake motions at a given site . they use this information to then make sure that buildings on that site do not have the same natural frequency as the expected earthquake input motions to avoid setting up resonance , in which the displacements of the building are amplified . what are some different strategies you might use to change the frequency of a building ? is it better to design buildings that are stiffer or more flexible ?
|
in 1815 , the eruption of mount tambora plunged parts of the world into darkness and marked a gloomy period that came to be known as the year without a summer . so when mary and percy shelley arrived at the house of lord byron on lake geneva , their vacation was mostly spent indoors . for amusement , byron proposed a challenge to his literary companions : who could write the most chilling ghost story ? this sparked an idea in 18-year-old mary . over the next few months , she would craft the story of frankenstein . popular depictions may evoke a green and groaning figure , but that 's not mary shelley 's monster . in fact , in the book , frankenstein refers to the nameless monster 's maker , dr. victor frankenstein . so tense is the struggle between creator and creature that the two have merged in our collective imagination . before you read or reread the original text , there are several other things that are helpful to know about frankenstein and how it came to assume its multiple meanings . the book traces dr. frankenstein 's futile quest to impart and sustain life . he constructs his monster part by part from dead matter and electrifies it into conscious being . upon completing the experiment , however , he 's horrified at the result and flees . but time and space are n't enough to banish the abandoned monster , and the plot turns on a chilling chase between the two . shelley subtitled her fireside ghost story , `` the modern prometheus . '' that 's in reference to the greek myth of the titan prometheus who stole fire from the gods and gave it to humanity . this gave humanity knowledge and power , but for tampering with the status quo , prometheus was chained to a rock and eaten by vultures for eternity . prometheus enjoyed a resurgence in the literature of the romantic period during the 18th century . mary was a prominent romantic , and shared the movement 's appreciation for nature , emotion , and the purity of art . two years after mary released `` frankenstein '' , percy reimagined the plight of prometheus in his lyrical drama , `` prometheus unbound . '' the romantics used these mythical references to signal the purity of the ancient world in contrast to modernity . they typically regarded science with suspicion , and `` frankenstein '' is one of the first cautionary tales about artificial intelligence . for shelley , the terror was not supernatural , but born in a lab . in addition , gothic devices infuse the text . the gothic genre is characterized by unease , eerie settings , the grotesque , and the fear of oblivion - all elements that can be seen in `` frankenstein . '' but this horror had roots in personal trauma , as well . the text is filled with references to shelley 's own circumstances . born in 1797 , mary was the child of william godwin and mary wollstonecraft . both were radical intellectual figures , and her mother 's book , `` a vindication of the rights of women , '' is a key feminist text . tragically , she died as a result of complications from mary 's birth . mary was haunted by her mother 's death , and later experienced her own problems with childbirth . she became pregnant following her elopement with percy at 16 , but that baby died shortly after birth . out of four more pregnancies , only one of their children survived . some critics have linked this tragedy to the themes explored in `` frankenstein . '' shelley depicts birth as both creative and destructive , and the monster becomes a disfigured mirror of the natural cycle of life . the monster , therefore , embodies dr. frankenstein 's corruption of nature in the quest for glory . this constitutes his fatal flaw , or hamartia . his god complex is most clear in the line , `` life and death appear to me ideal bounds which i should first break through and pour a torrent of light onto our dark world . '' although he accomplishes something awe-inspiring , he has played with fire at his own ethical expense . and that decision echoes throughout the novel , which is full of references to fire and imagery that contrasts light and dark . these moments suggest not only the spark of prometheus 's fire , but the power of radical ideas to expose darker areas of life .
|
but this horror had roots in personal trauma , as well . the text is filled with references to shelley 's own circumstances . born in 1797 , mary was the child of william godwin and mary wollstonecraft . both were radical intellectual figures , and her mother 's book , `` a vindication of the rights of women , '' is a key feminist text .
|
how does mary shelley ’ s position as a young pregnant woman manifest in the text ?
|
translator : andrea mcdonough reviewer : bedirhan cinar it is only in the last 100 or so years that human kind has understood that the nucleus of the chemical elements is not always fixed . it can change spontaneously from one element to another . the name for this process is radioactivity . you probably already know something about the nucleus : it 's much tinier than the atom , it 's made of particles called protons and neutrons , there are electrons orbiting around it . and though the atoms can share or swap electrons when they bond together , the nuclei themselves never change . right ? well , no . certain nuclei are not stable in that way . this means they may change suddenly , spontaneously . the radioactive nucleus flings out a small particle and transforms into another element , just like that . for example , the carbon nucleus can eject a fast-moving electron and turn into a nitrogen nucleus . there are two different particles that can be emitted from radioactive nuclei , but never together . the very fast electron is known as a beta particle . if you know a little bit about electrons , you may be thinking , `` what was the electron doing in the nucleus in the first place ? '' the answer is there is a neutron in nucleus spontaneously changed into a proton , which stayed behind , and the electron flew out as a beta particle . this is not what chemistry has taught us to expect . the nucleus is supposed to be stable . neutrons do n't change into protons . except , sometimes they do ! the other particle it emits spontaneously from an unstable nucleus is alpha . an alpha particle is 8,000 times more massive than beta , and it 's a bit slower . alpha is made from two protons and two neutrons . if we trap all those alpha particles together , we get helium gas . alpha is a helium nucleus . like the beta particle , you would not have expected a heavier nucleus to throw out helium . but again , it happens , and the nucleus becomes a new element . so , is radioactivity useful or just dangerous ? wherever you are sitting , it is quite likely that there is a device nearby which contains a source of alpha particles : a smoke detector . the source is radioactive americium . you are totally safe from these alpha particles , which can not travel more than a few centimeters in air . beta particles penetrate much farther through materials than alpha can . radioactive atoms are used in medicine as traces , to show where chemicals travel in the patient . beta particles are emitted and have enough energy to emerge from the body and be detected . there is a third type of nuclear radiation : gamma , which is not a particle at all . it is an electromagnetic wave , like microwaves , or light , but it is actually 1,000 times more energentic than visible light . gamma rays may pass right through your body . gamma is used to zap the bacteria in fruit to increase its shelf life , or in radiotherapy to kill cancer cells . radioactive substances get hot , and this heat can be used to generate power . this heat has been brought to you since space probes , and , in the past , in pacemakers for hearts . the more abruptly nuclear radiation is slowed down , the more damage it does to the atoms it hits . this is called ionization . alpha causes the most ionization as it crashes into other atoms and gamma the least . in humans , the most serious effect of radiation is the damage that it can cause to our dna . although alpha can not penetrate your skin , if you inhale or injest a radioactive nucleus , the health consequences can be severe . radioactivity is both useful and deadly , but it is all around us as a background to the natural world .
|
alpha causes the most ionization as it crashes into other atoms and gamma the least . in humans , the most serious effect of radiation is the damage that it can cause to our dna . although alpha can not penetrate your skin , if you inhale or injest a radioactive nucleus , the health consequences can be severe .
|
the most serious effect of radiation on humans is :
|
on august 21 , 2017 the shadow of the moon will pass from the west coast to the east coast of the u.s. our blue sky will turn black as night and fill with stars , and there will be a hole in the sky where the sun used to be , surrounded by the fiery ring of the sun 's corona , a total eclipse of the sun . this will truly be a historic event . accounts of solar eclipses date way back on the written record . the early mesopotamians wrote that the sun was put to shame during the solar eclipse of the 14th century b.c.e . and it may have started the sun worship of the egyptian pharaoh akhenaten . ancient chinese astrologers paid with their lives if they failed to predict the solar eclipse and portend the fate of their emperors whose symbol was the sun . the earliest date of a specific event in human history , a battle between the armies of lydia and media , occurred on may 28 , 535 b.c.e . when a solar eclipse caused the soldiers to lay down their arms and declare a truce . so how does it happen ? during a total solar eclipse , the moon moves between the earth and the sun . when this happens , the disc of the moon appears to perfectly cover the disc of the sun even though the sun is much larger than the moon . but how is this possible ? the sun is 400 times bigger than the moon , but by sheer coincidence , the moon is 390 times closer to earth . size and distance cancel each other out so that the moon and sun appear to be almost the exactly same size . every time the moon orbits the earth , once every 27.3 days , it has to pass between the earth and the sun , a stage called the new moon phase . and every time it passes , the new moon has a chance to block out the sun . most of the time , the moon passes a little above or a little below the sun , but if they align perfectly , the shadow of the moon will make a narrow path across earth and those in the shadows will see a total solar eclipse . just like on night side of the earth , the sky during a total eclipse is black and filled with stars . but while the moon perfectly covers the surface of the sun , it does n't block out the sun 's outer atmosphere , its corona , which appears as a fiery ring around the dark disc of the moon . solar eclipses occur several times a year , but most often they are partial eclipses where the moon does n't quite line up with the sun . and , when the moon and sun are perfectly aligned , the moon is usually too far from earth in its orbit to completely cover the sun , creating an annular eclipse . during an annular or partial eclipse , the sky remains bright . even on those rare occasions of a total eclipse , the moon 's shadow is most likely to fall on the 70 % of earth that is covered by water , and few people , if any , will see it . the eclipse of 2017 will be remarkable on a larger scale because the moon is slowly moving away from earth . if a furry ancestor of ours had bothered to look up during a solar eclipse a hundred million years ago , it would n't have seen the fiery corona of the sun . it would have just been dark . eventually , the moon will have moved too far from earth to completely cover the disc of the sun . it is only during our little wink of earth 's history that the moon is at just the right distance to cause a total solar eclipse yet not block the sun 's corona . so on august 21 , 2017 , when the moon exactly lines up with the sun and the moon is close enough to the earth , its shadow will cross the u.s. and , if you happen to be in its narrow path , you will witness one of the most awe-inspiring sights in the universe . but , as incredible as this event will be , total eclipses are one of the most dangerous as well . only specially tinted filters , specifically designed to observe the sun , should be used . the eclipse might put the sun to shame , but even a shamed sun can seriously damage your eyes .
|
so how does it happen ? during a total solar eclipse , the moon moves between the earth and the sun . when this happens , the disc of the moon appears to perfectly cover the disc of the sun even though the sun is much larger than the moon .
|
what do we call the sun ’ s outer atmosphere that is visible around the dark disk of the moon during a total solar eclipse ?
|
mysteries of vernacular : x-ray , a form of electromagnetic radiation capable of penetrating solids . the word x-ray harkens back to the work of rene descartes , a french philosopher , mathematician , and writer in the 17th century . one of descartes innumerable contributions to the world of numbers was the invention of a simple yet brilliant convention most people take for granted today : the representation of unknowns within an equation as x , y , and z . when the german scientist wilhelm rontgen discovered what we now call x-rays in the late 19th century , he gave them the name x-strahlen . strahlen is german for shine , and x , of course , represented the unknown nature of the radiation rontgen had discovered , the x-factor , so to speak . the english translation maintained the x but replaced the german shine with ray , meaning a beam of light . coincidentally , in mathematics , the word ray refers to a line with a point of origin that has no end and extends to infinity , bringing us neatly back to the unknown . today we understand what x-radiation is , and in spite of the humble objections of its discoverer , it is also commonly called rontgen radiation , eliminating with the x the fundamental mystery of its nature .
|
the word x-ray harkens back to the work of rene descartes , a french philosopher , mathematician , and writer in the 17th century . one of descartes innumerable contributions to the world of numbers was the invention of a simple yet brilliant convention most people take for granted today : the representation of unknowns within an equation as x , y , and z . when the german scientist wilhelm rontgen discovered what we now call x-rays in the late 19th century , he gave them the name x-strahlen . strahlen is german for shine , and x , of course , represented the unknown nature of the radiation rontgen had discovered , the x-factor , so to speak .
|
how are x , y and z used in mathematical equations ?
|
translator : andrea mcdonough reviewer : jessica ruby enough mutations can bypass these fail-safes , driving these cells to divide recklessly . that one rogue cell becomes two , then four , then eight . `` how do you animate real materials , like brains and nerves and stuff like that ? how do you take something that does n't move and then make it move ? '' `` so , that 's actually , we used a method called stop-motion animation , in which you are moving the objects underneath the camera , each frame , one at a time , and you take a picture for each picture that you 've created . so , for this , we were watching a lot of videos on how cell division works , and from that , i created a line-drawn animation that was my reference animation . and , using the software that we use for stop-motion , i was actually able to look at that reference material while shooting so i could kind of arrange underneath the camera in order to match my animation as i would follow along . and we actually shot all of this on a green screen , and the purpose of using the green screen was , for example , in the scene where you see many cells dividing at one time , for me to have actually have to animate each of those cells unanimously dividing at the same time would have been a lot of work that we would n't have had time for . so , the green screen allowed me to do a couple of cell divisions that i could then duplicate in order to show cell division : two , then four , then eight . '' `` so , you only have to basically actually record it once and then you can just duplicate it on the computer . '' `` exactly . '' `` so , it sounds really painstaking . how long did it take to , like , record one cell division ? '' `` i think i did in a day , i did a couple of cell divisions . so , sort of a full work day , so , probably a couple of hours for one . i think , actually , the stuff that took longer was the text . we were animating the word , 'growth ' . we were animating it getting smaller and taller and wider . and for this , i was literally adding one single seed at a time in order to create that animation . '' `` so , how did you animate the word cancer ? '' `` i actually started with the word cancer written and moved backwards and was surgically removing one seed at a time , and then we played that photage backwards to make it look like it was appearing . we use that trick a lot of times in stop-motion because if you want things to really conform , any time that you 're having things come together or fall apart , it usually makes more sense to start with that together frame and work from there , and do the scatter from there , and then , just play that in reverse . it 's a little too painstaking . stop-motion is painstaking , it 's a labor of love , but you have to also be practical when you have a deadline . '' `` so , there 's this technique that you guys use to make the cells look like they 're alive so they 're not just sitting there . that 's called shimmering . how does that work exactly ? '' `` so , in animation , shimmering is usually when you are , if you 're doing drawn animation , you 're drawing that same drawing multiple times but with slight variations so that way , you do n't have a stagnant , still frame under the camera . with the cells , using the seeds and the nerds , we had the opportunity to really have a look , like they were kind of vibrating and pulsating in a way . and so , those are actually , depending on the cell , three to five pictures . with the candy nerds , i would rearrange their position each time so there 's actually removing all the colorful nerds , leaving the purple ones in the center and moving the colorful ones back in into a different position . but with the seeds , when the seeds were shimmering , for that , i would actually just very , very , very lightly , like , roll my hand over it very slightly and then make sure none of them fell out of the constraints of the cell , fix the edges , and take that picture , and just slightly do that again . so , it just slightly changes their position or rustles them up a little bit so that would cycle over and over . and those would play on what animators call threes . and threes means that each picture is on screen for three frames at twenty-four frames per second . so , for the shimmers , you were seeing eight different pictures each second of footage . '' `` how much of your sweat and tears are on these nerds ? '' `` i think , actually , to be honest , the part that was the most perspirational of using the nerds for animation was the place where we had to separate them into colors in order to use them to animate . every time i would put them on the screen to animate , on the tabletop to animate , i would have to separate them out at the end of the day again . and that was the most frustrating part . and , honestly , up until , like , three weeks ago , i dropped my purse on the ground and , like , lentils came out of my purse and onto the floor . like , there 's , this video will stay with me forever . '' `` in your bag . '' `` in my bag . it goes wherever i go . ''
|
so , it just slightly changes their position or rustles them up a little bit so that would cycle over and over . and those would play on what animators call threes . and threes means that each picture is on screen for three frames at twenty-four frames per second .
|
explain what is meant by `` threes . ''
|
hannah fry : so today we 're going to talk about rock-paper-scissors and i reckon everyone knows how to play it scissors beats paper , paper covers rock , rock blunts scissors , so three -- brady : wait , i always thought it smashed them ? dr. fry : oh , i thought it blunts them actually , if anything , it would probably sharpen them , right ? there are three strategies , each one of them loses once and wins once so it looks like there 's no strategy that you can play to win , but i 'm going to show you about a new paper that had just come out where it gives you some top tips of how to win so it 's a group of chinese scientists , where they run an experiment where they got 360 students to play games of rock-paper-scissors with one another 300 rounds in every game , which took up to 2 hours , which is astonishing , students playing rock-paper-scissors for 2 hours okay , so normally if you have rock-paper-scissors and some of you had rock ( r ) up there , and rock is beaten by paper ( p ) , which is then beaten by scissors ( s ) so none of these strategies dominate the other , so really all you can do is play each strategy with an equal probability : 1/3 , 1/3 , 1/3 , okay now , if you were playing against a computer , who was choosing these perfectly randomly , then that would be the best thing for you to do -- just to pick each strategy with equal probability but the thing is , humans are quite predictably irrational , so to say , in the way they choose their strategy so , in recording what one of these students did in playing rock-paper-scissors the scientists came up with two quite important findings of how people try to beat each other okay , so the first one is that people who win tend to repeat their strategy so , for example , if i beat you by playing rock , there is a very high chance , or high probability that i will play rock again the second time . if it worked once , it 's going to work again , right ? the second thing that they found out is that losers change brady : to anything in particular , or ... ? dr. fry : well , so this is a thing that you can exploit , essentially so if you know -- so this gives us , i suppose , two strategies that we can use so the first tip is that if you lose , that means the other person just won , right ? so let 's imagine that your opponent won by playing rock now , the chances are that they 're going to play rock again , you should then play paper so you just lost on scissors , so you should play paper which means that , basically , even though paper beats rock ( so the cycle goes around like this : paper beats rock and so on ) you should go the other way around the triangle let 's imagine that you played scissors , the other person played rock , what you should do is you should go backwards around this triangle and play paper the next time because of the high chance that they 're going to play rock again so that 's the first thing : go backwards , i guess or another way to say it is -- essentially , you 've just played scissors , they 've played rock so play the thing that did n't come up in that , if you lose now the second thing , is that if you 've just won now , they 're going to expect you to play the same thing again , right ? which means , that they 're going to play the thing that you would beat the thing that you just played so you need to play the thing that would beat that would beat the thing that you just played which is equivalent to saying , you need to play what they just played you want to [ laughs ] let 's go again [ both laugh ] brady : i like the easy way better , so you should play what they just played dr. fry : you should play what they just played , yes so let 's imagine , then , you just won -- you played rock , right ? -- and you just won on rock that means that they played scissors , now they 're going to think that you 're going to play rock again , which means that they 're going to play paper , which means that you should play scissors and so again , you basically end up going backwards around the triangle so play what they just played , and the game go backwards or an easier way to say it then is to play what they just played . so in general , if you 're cycling through rock-paper-scissors , your best strategy is to go backwards and go scissors-paper-rock , and cycle through that way brady : how much -- is this mathematics or is this psychology ? this is -- i ca n't tell if this is all to do with probability , or it 's just about knowing how humans think dr. fry : well , i think that a balance of the two , so it 's rooted in game theory which is the mathematics of looking at decisions and strategies , so in any situation where you 're competing against someone , and you best move is dependent on what the other person is playing , you can frame in game theory brady : numberphile is brought to you by the mathematical sciences research institute but this video has also been sponsored by squarespace squarespace is a great service for designing , hosting , creating your own websites and as probably mentioned before , i use it myself no matter what you want to do -- a blog , podcast , shop , portfolio , squarespace is as easy as 1-2-3 but it 's not just amateurs who benefit from squarespace and all its brilliant templates , their developer platform will also give you full control over all the code , letting you tweak the html , css and javascript into your heart 's content and if you like stats , and you 're watching numberphile , you 'll really like watching squarespace 's analytics , their 3rd party integrations , and their easy-to-use commerce if you 'd like to find out more , go to squarespace.com/numberphile you can try it all out , you can set up your own site , and you can do it all for free , no credit card required and then if you do like it , and decide to opt in , use the offer code numberphile and you get 10 % off so thank you very much to squarespace for supporting this video and thank you to you for watching it
|
there are three strategies , each one of them loses once and wins once so it looks like there 's no strategy that you can play to win , but i 'm going to show you about a new paper that had just come out where it gives you some top tips of how to win so it 's a group of chinese scientists , where they run an experiment where they got 360 students to play games of rock-paper-scissors with one another 300 rounds in every game , which took up to 2 hours , which is astonishing , students playing rock-paper-scissors for 2 hours okay , so normally if you have rock-paper-scissors and some of you had rock ( r ) up there , and rock is beaten by paper ( p ) , which is then beaten by scissors ( s ) so none of these strategies dominate the other , so really all you can do is play each strategy with an equal probability : 1/3 , 1/3 , 1/3 , okay now , if you were playing against a computer , who was choosing these perfectly randomly , then that would be the best thing for you to do -- just to pick each strategy with equal probability but the thing is , humans are quite predictably irrational , so to say , in the way they choose their strategy so , in recording what one of these students did in playing rock-paper-scissors the scientists came up with two quite important findings of how people try to beat each other okay , so the first one is that people who win tend to repeat their strategy so , for example , if i beat you by playing rock , there is a very high chance , or high probability that i will play rock again the second time . if it worked once , it 's going to work again , right ? the second thing that they found out is that losers change brady : to anything in particular , or ... ?
|
explain why the strategy of moving backwards through your choices should work .
|
this is a thought experiment . let 's say at some point in the not so distant future , you 're barreling down the highway in your self-driving car , and you find yourself boxed in on all sides by other cars . suddenly , a large , heavy object falls off the truck in front of you . your car ca n't stop in time to avoid the collision , so it needs to make a decision : go straight and hit the object , swerve left into an suv , or swerve right into a motorcycle . should it prioritize your safety by hitting the motorcycle , minimize danger to others by not swerving , even if it means hitting the large object and sacrificing your life , or take the middle ground by hitting the suv , which has a high passenger safety rating ? so what should the self-driving car do ? if we were driving that boxed in car in manual mode , whichever way we 'd react would be understood as just that , a reaction , not a deliberate decision . it would be an instinctual panicked move with no forethought or malice . but if a programmer were to instruct the car to make the same move , given conditions it may sense in the future , well , that looks more like premeditated homicide . now , to be fair , self-driving cars are are predicted to dramatically reduce traffic accidents and fatalities by removing human error from the driving equation . plus , there may be all sorts of other benefits : eased road congestion , decreased harmful emissions , and minimized unproductive and stressful driving time . but accidents can and will still happen , and when they do , their outcomes may be determined months or years in advance by programmers or policy makers . and they 'll have some difficult decisions to make . it 's tempting to offer up general decision-making principles , like minimize harm , but even that quickly leads to morally murky decisions . for example , let 's say we have the same initial set up , but now there 's a motorcyclist wearing a helmet to your left and another one without a helmet to your right . which one should your robot car crash into ? if you say the biker with the helmet because she 's more likely to survive , then are n't you penalizing the responsible motorist ? if , instead , you save the biker without the helmet because he 's acting irresponsibly , then you 've gone way beyond the initial design principle about minimizing harm , and the robot car is now meting out street justice . the ethical considerations get more complicated here . in both of our scenarios , the underlying design is functioning as a targeting algorithm of sorts . in other words , it 's systematically favoring or discriminating against a certain type of object to crash into . and the owners of the target vehicles will suffer the negative consequences of this algorithm through no fault of their own . our new technologies are opening up many other novel ethical dilemmas . for instance , if you had to choose between a car that would always save as many lives as possible in an accident , or one that would save you at any cost , which would you buy ? what happens if the cars start analyzing and factoring in the passengers of the cars and the particulars of their lives ? could it be the case that a random decision is still better than a predetermined one designed to minimize harm ? and who should be making all of these decisions anyhow ? programmers ? companies ? governments ? reality may not play out exactly like our thought experiments , but that 's not the point . they 're designed to isolate and stress test our intuitions on ethics , just like science experiments do for the physical world . spotting these moral hairpin turns now will help us maneuver the unfamiliar road of technology ethics , and allow us to cruise confidently and conscientiously into our brave new future .
|
for example , let 's say we have the same initial set up , but now there 's a motorcyclist wearing a helmet to your left and another one without a helmet to your right . which one should your robot car crash into ? if you say the biker with the helmet because she 's more likely to survive , then are n't you penalizing the responsible motorist ?
|
if a robot car reacts exactly as a human would in a crash scenario , which would be true ?
|
if you 've had surgery , you might remember starting to count backwards from ten , nine , eight , and then waking up with the surgery already over before you even got to five . and it might seem like you were asleep , but you were n't . you were under anesthesia , which is much more complicated . you were unconscious , but you also could n't move , form memories , or , hopefully , feel pain . without being able to block all those processes at once , many surgeries would be way too traumatic to perform . ancient medical texts from egypt , asia and the middle east all describe early anesthetics containing things like opium poppy , mandrake fruit , and alcohol . today , anesthesiologists often combine regional , inhalational and intravenous agents to get the right balance for a surgery . regional anesthesia blocks pain signals from a specific part of the body from getting to the brain . pain and other messages travel through the nervous system as electrical impulses . regional anesthetics work by setting up and electrical baracade . they bind to the proteins in neurons ' cell membranes that let charged particles in and out , and lock out positively charged particles . one compound that does this is cocaine , whose painkilling effects were discovered by accident when an ophthalmology intern got some on his tongue . it 's still occasionally used as an anesthetic , but many of the more common regional anesthetics have a similar chemical structure and work the same way . but for major surgeries where you need to be unconscious , you 'll want something that acts on the entire nervous system , including the brain . that 's what inhalational anesthetics do . in western medicine , diethyl ether was the first common one . it was best known as a recreational drug until doctors started to realize that people sometimes did n't notice injuries they received under the influence . in the 1840s , they started sedating patients with ether during dental extractions and surgeries . nitrous oxide became popular in the decades that followed and is still used today . although ether derivatives , like sevoflurane , are more common . inhalational anesthesia is usually supplemented with intravenous anesthesia , which was developed in the 1870s . common intravenous agents include sedatives , like propofol , which induce unconsciousness , and opioids , like fentanyl , which reduce pain . these general anesthetics also seem to work by affecting electrical signals in the nervous system . normally , the brain 's electrical signals are a chaotic chorus as different parts of the brain communicate with each other . that connectivity keeps you awake and aware . but as someone becomes anesthetized , those signals become calmer and more organized , suggesting that different parts of the brain are n't talking to each other anymore . there 's a lot we still do n't know about exactly how this happens . several common anesthetics bind to the gaba-a receptor in the brain 's neurons . they hold the gateway open , letting negatively charged particles flow into the cell . negative charge builds up and acts like a log jam , keeping the neuron from transmitting electrical signals . the nervous system has lots of these gated channels , controlling pathways for movement , memory , and consciousness . most anesthetics probably act on more than one , and they do n't act on just the nervous system . many anesthetics also affect the heart , lungs , and other vital organs . just like early anesthetics , which included familiar poisons like hemlock and aconite , modern drugs can have serious side effects . so an anesthesiologist has to mix just the right balance of drugs to create all the features of anesthesia , while carefully monitoring the patient 's vital signs , and adjusting the drug mixture as needed . anesthesia is complicated , but figuring out how to use it allowed for the development of new and better surgical techniques . surgeons could learn how to routinely and safely perform c-sections , reopen blocked arteries , replace damaged livers and kidneys , and many other life-saving operations . and each year , new anesthesia techniques are developed that will ensure more and more patients survive the trauma of surgery .
|
that 's what inhalational anesthetics do . in western medicine , diethyl ether was the first common one . it was best known as a recreational drug until doctors started to realize that people sometimes did n't notice injuries they received under the influence .
|
technology has progressed very rapidly these past few decades , and this includes medicine . can you think of anything that will become the standard of medical practice in the next 10 years ? for example , doctors using computers to write notes on patients instead of writing them by hand .
|
translator : andrea mcdonough reviewer : bedirhan cinar picture this : your friend and you are watching a sitcom and a sassy sidekick walks into a room , carrying a four-tiered wedding cake . he trips , falls , and face-plants into the cake . your friend doubles over with laughter and says , `` it 's so ridiculous ! so ironic ! '' well , quick , what do you do ? do you laugh along with the laugh track and let this grievous misinterpretation of irony go ? or , do you throw caution to the wind and explain the true meaning of irony ? if you 're me , you choose the latter . unfortunately , irony has been completely misunderstood . we tend to throw out that term whenever we see something funny or coincidental . and while many examples of true irony can be funny , that is not the driving factor of being ironic . a situation is only ironic if what happens is the exact opposite of what was expected . if you expect a , but get b , then you have irony . let 's take the slap-stick cake situation as an example . when someone walks in precariously balancing something that should n't be carried alone , trips , falls , and makes a mess , it is funny , but it 's not ironic . in fact , you probably expect someone who is single-handedly carrying a huge cake to trip . when he does , reality aligns with expectations , and so that is not irony . but what if the sassy sidekick walked in wearing a gold medal that he 'd won at the cake walking event at the atlanta olympics in 1996 ? what if that sidekick was a professional cake carrier ? then , maybe there would have been a reasonable expectation that he would have been more skilled when carrying a ridiculously large cake . then , when that reasonable expectation was not met by the tripping sidekick , irony would have been exemplified . another example . a senior citizen texting and blogging . the common and reasonable expectation of more mature men and women is that they do n't like or know technology , that they have a hard time turning on a computer , or that they have the old brick cell phones from the 1980s . one should not expect them to be connected , high-tech , or savvy enough to text or to be blogging , which must seem like some sort of newfangled thing that `` back in my day , '' they never had . so when granny pulls out her smart phone to post pictures of her dentures or her grandkids , irony ensues . reasonable expectations of the situation are not met . that is irony . so while the cake dropper might not be ironic , there are all kinds of situations in life that are . go out , and find those true examples of irony .
|
your friend doubles over with laughter and says , `` it 's so ridiculous ! so ironic ! '' well , quick , what do you do ?
|
a situation is only ironic if what happens is ___________ .
|
imagine an island where 100 people , all perfect logicians , are imprisoned by a mad dictator . there 's no escape , except for one strange rule . any prisoner can approach the guards at night and ask to leave . if they have green eyes , they 'll be released . if not , they 'll be tossed into the volcano . as it happens , all 100 prisoners have green eyes , but they 've lived there since birth , and the dictator has ensured they ca n't learn their own eye color . there are no reflective surfaces , all water is in opaque containers , and most importantly , they 're not allowed to communicate among themselves . though they do see each other during each morning 's head count . nevertheless , they all know no one would ever risk trying to leave without absolute certainty of success . after much pressure from human rights groups , the dictator reluctantly agrees to let you visit the island and speak to the prisoners under the following conditions : you may only make one statement , and you can not tell them any new information . what can you say to help free the prisoners without incurring the dictator 's wrath ? after thinking long and hard , you tell the crowd , `` at least one of you has green eyes . '' the dictator is suspicious but reassures himself that your statement could n't have changed anything . you leave , and life on the island seems to go on as before . but on the hundredth morning after your visit , all the prisoners are gone , each having asked to leave the previous night . so how did you outsmart the dictator ? it might help to realize that the amount of prisoners is arbitrary . let 's simplify things by imagining just two , adria and bill . each sees one person with green eyes , and for all they know , that could be the only one . for the first night , each stays put . but when they see each other still there in the morning , they gain new information . adria realizes that if bill had seen a non-green-eyed person next to him , he would have left the first night after concluding the statement could only refer to himself . bill simultaneously realizes the same thing about adria . the fact that the other person waited tells each prisoner his or her own eyes must be green . and on the second morning , they 're both gone . now imagine a third prisoner . adria , bill and carl each see two green-eyed people , but are n't sure if each of the others is also seeing two green-eyed people , or just one . they wait out the first night as before , but the next morning , they still ca n't be sure . carl thinks , `` if i have non-green eyes , adria and bill were just watching each other , and will now both leave on the second night . '' but when he sees both of them the third morning , he realizes they must have been watching him , too . adria and bill have each been going through the same process , and they all leave on the third night . using this sort of inductive reasoning , we can see that the pattern will repeat no matter how many prisoners you add . the key is the concept of common knowledge , coined by philosopher david lewis . the new information was not contained in your statement itself , but in telling it to everyone simultaneously . now , besides knowing at least one of them has green eyes , each prisoner also knows that everyone else is keeping track of all the green-eyed people they can see , and that each of them also knows this , and so on . what any given prisoner does n't know is whether they themselves are one of the green-eyed people the others are keeping track of until as many nights have passed as the number of prisoners on the island . of course , you could have spared the prisoners 98 days on the island by telling them at least 99 of you have green eyes , but when mad dictators are involved , you 're best off with a good headstart .
|
if not , they 'll be tossed into the volcano . as it happens , all 100 prisoners have green eyes , but they 've lived there since birth , and the dictator has ensured they ca n't learn their own eye color . there are no reflective surfaces , all water is in opaque containers , and most importantly , they 're not allowed to communicate among themselves .
|
why do n't the prisoners know their own eye color ?
|
translator : andrea mcdonough reviewer : bedirhan cinar ever wonder where most of the food you eat every day comes from ? well , about 60 % of the food you eat is carbohydrates . as you can probably tell from its name , carbohydrates contain carbon , hydrogen , and oxygen . but where do these atoms originally come from and how do they join together to make delicious foods like fruits and pasta ? it actually all starts with the air you are exhaling this very minute , specifically the carbon dioxide molecules . plants are going to breath in this very same carbon dioxide through pores in their skin , called stomata . plants drink in water from their roots to get the needed oxygen and hydrogen atoms , and their electrons , in order to build carbohydrates . what is that thing ? well , that 's a special plant organelle inside the leaves of plants called a chloroplast . it 's green beceause of a special light-absorbing pigment called chlorophyll . each leaf has about 44,000 cells and every cell can have anywhere between 20 to 100 chloroplasts . that 's up to 4,400,000 chloroplasts ! by now , you 've probably guessed that we 're talking about the process of photosynthesis and you might be wondering when the sun is going to make its entrance . let 's go back to that original molecule of water . the plant has to split this molecule of water so it can get electrons from it . but , the plant ca n't pull that water apart by itself . it needs help from the high-energy rays of the sun . so now that the chloroplast has all the building blocks - carbon , hydrogen , oxygen , and electrons - it can use them to go through the rest of the steps of photosynthesis to transform that original carbon dioxide gas into a simple carbohydrate called glucose , c-6-h-12-o-6 . that little glucose molecule then helps to build bigger and better carbohydrates like cellulose . cellulose is a type of carbohydrate found in plants that our body can not break down . we call it fiber and we eat it in vegetables like lettuce , broccoli , and celery . plants use cellulose to keep themselves strong . the plant could also turn that glucose into starch , a large molecule that stores energy for the plant . we love eating starch from plants like potatoes , corn , and rice . so you see , when you eat plants , we 're actually benefiting from photosynthesis . the plant makes things like starch , which we eat and then break back down into glucose , the first form the plant made . then , the mitochondria in our cells , powered by the oxygen we breath , can turn glucose into pure energy molecules called atp . atp powers all work done by each and every one of your cells , things like communication , movement , and transport . but why do we have to turn that glucose into atp ? well , think of it like this . you 're excited to start your summer job at the local ice cream stand , but your boss has just told you that she is going to pay you in ice cream cones . what are you going to be able to do with those ice cream cones ? nothing , which is why you kindly asked to be paid in dollars . atp is just like dollars . it is the currency that all cells of life use while glucose is , well , kind of like ice cream . even plants have mitochondria in their cells to break down the glucose they make into atp . so as you can see , humans and plants are intricately connected . the air we breath out is used by plants to make the carbohydrates we enjoy so much . and , in the process , they are releasing the very same oxygen molecules we need to breath in in order that our mitochondria can break down our delicous carbohydrate meal .
|
we love eating starch from plants like potatoes , corn , and rice . so you see , when you eat plants , we 're actually benefiting from photosynthesis . the plant makes things like starch , which we eat and then break back down into glucose , the first form the plant made .
|
in five sentences or less , list the major steps involved in photosynthesis .
|
[ music playing ] getting sick stinks -- literally . what i mean is that different diseases give off different odors , and sometimes doctors can diagnose you based on how you smell . i 'm anna rothschild , and this is `` gross science . '' so it turns out that doctors have known since the time of hippocrates that different diseases smell different ways . for example , typhoid -- which causes fever , abdominal pain , delirium , and can kill you -- smells like freshly baked brown bread . other infections smell totally differently . the skin of people with the virus yellow fever is said to smell like a butcher shop . and if you have a burn wound infected with the bacteria pseudomonas , it might smell like grape juice . but infections from bacteria and viruses are n't the only diseases that can make you emit a certain aroma . genetic conditions -- ones you 're born with -- can do the same thing . for example , maple syrup urine disease , which can be fatal if untreated , makes you smell like maple syrup . and then there 's a condition called trimethylaminuria , which has absolutely no symptoms , except that it makes you smell like rotten fish . and those are just diseases that humans can smell . dogs can actually sniff out certain types of cancer , and scientists have now created electronic noses . these are smelling machines that can detect very faint traces of compounds that the human nose would never be able to pick up . beep boop beep . in fact , researchers are looking into using dogs or e-noses to detect diseases before they become dangerous . so while sniffing out the source of an illness has never really gone away , there 's a whole new frontier of stench science out there . just take a whiff . ew . what 's the grossest thing you 've ever smelled ? let me know in the comments . and for more `` gross science '' and weird facts , hit subscribe .
|
and if you have a burn wound infected with the bacteria pseudomonas , it might smell like grape juice . but infections from bacteria and viruses are n't the only diseases that can make you emit a certain aroma . genetic conditions -- ones you 're born with -- can do the same thing .
|
true or false : diseases from bacteria and viruses are the only diseases that give off smells .
|
translator : andrea mcdonough reviewer : jessica ruby mysteries of vernacular : fizzle , to end weakly or to fail , to die out . the definition of fizzle likely links back to the old english word fist , which meant stink . in the mid-fifteenth century , fist developed into the verb fisten , to break wind , which eventually lead to the modern word feisty , but that 's another story . in its earliest form , as a variant of fisten , fizzle had a very specific meaning : to break wind without noise . surprisingly , considering this initial definition , by the 1800s , the word fizzle referred instead to a specific sound , rather graphically , to the sputtering or hissing of a gas or liquid being forced out of a narrow opening . the figurative sense of the word , a weak ending , is thus understandable within the context of a flame consuming the last drops of oil in a lantern or a valve drawing out the contents of the bottom of a cask . though perhaps not derived directly from this subsiding verb , our modern meaning of fizzle developed as slang in the 1800s . originally used on college campuses to describe failure , specifically on an exam , it was n't long before the word came to mean exactly what it does today and was quickly and widely adopted .
|
translator : andrea mcdonough reviewer : jessica ruby mysteries of vernacular : fizzle , to end weakly or to fail , to die out . the definition of fizzle likely links back to the old english word fist , which meant stink . in the mid-fifteenth century , fist developed into the verb fisten , to break wind , which eventually lead to the modern word feisty , but that 's another story .
|
what was the original meaning of the word fist ?
|
honeybees are fascinating creatures for a number of reasons : their incredible work ethic , the sugary sweet syrup they produce and their intricate social structure . but another reason is that honeybees are , in fact , excellent mathematicians . scientists claim the tiny insects can calculate angles , and can even comprehend the roundness of the earth . but there 's particular mathematical bee genius behind the most important aspect of honeybee life : the hive . just like humans , bees need food and shelter to stay alive . the hive is not only the bees ' home , but doubles as a place to store their honey . since it 's so central to survival , honeybees have to perfect the hive 's architectural design . if you examine any piece of honeycomb , you 'll see that it 's constructed from tightly packed hexagonal , or six-sided , cells . of all the possible designs , why do honeybees choose this one ? to understand , you need to think like a bee . bees need a secure place for their entire colony to live . similarly , there needs to be a place where their nectar can be stored and ripened suitably until it turns into honey . that means there 's a need for some serious space efficiency . a good solution is to build little storage units , or cells , just big enough for a bee to fit into , which can also double as the containers in which nectar is stored : the bees ' very own honey jars . the next thing , is to decide what the little cells should be made out of . bees do n't have beaks or arms to pick up things , but they are capable of producing wax . the thing is , producing it is a lot of hard work . bees have to consume 8 ounces of honey to produce just 1 ounce of wax . so they do n't want to waste it . so , they need a design that allows them to store the largest possible amount of honey using the least amount of wax . what shape does that ? imagining for a minute that all bees had to attend architecture academy and go to math class . let 's say they asked their geometry teacher , `` what shape would give us the most space to store our honey , but require the least amount of wax ? '' and then geometry teacher replied , `` the shape that you 're seeking is the circle . '' leaving the bees to return to their trial construction site and begin building their honeycomb using circular cells . after a while , some of them might have noticed a problem with their design : small gaps between the cells . `` we ca n't even fit in there ! that 's wasted space ! '' they might have thought . so , ignoring the geometry lesson , and taking matters into their own hands , the bees went back to the drawing board to rethink their beehive design . one suggested triangles , `` we can use triangles . look ! they fit together perfectly . '' another bee suggested squares . finally , a third bee piped up and said , `` pentagons do n't seem to work , but hexagons do ! we want the one that will use the least amount of wax and be able to store the most amount of honey . yes , i think that 's the hexagon . '' `` why ? '' `` it looks more like the circle than the others . '' `` but how do we know for sure ? '' to find out , the industrious insect architects calculated the areas of the triangle , the square and the hexagon and found that the hexagon was , in fact , the shape that gave them the most storage space . they agreed on an ideal size and returned to work . the space efficient comb that is a bee 's trademark today , is probably the result of this trial and error , but over long periods of evolutionary history . however , it paid off . peek into any hive -- with your protective goggles and netting on , of course -- and you 'll see the end result : a beautiful compact honeycomb that any architect would have be proud to design .
|
honeybees are fascinating creatures for a number of reasons : their incredible work ethic , the sugary sweet syrup they produce and their intricate social structure . but another reason is that honeybees are , in fact , excellent mathematicians . scientists claim the tiny insects can calculate angles , and can even comprehend the roundness of the earth .
|
explain why the fact that a circle maximizes area for a given perimeter translates to the statement that a cylinder maximizes the volume for a given surface area .
|
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 .
|
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 .
|
when you walk through the forest , what you see is just the tip of the iceberg . why is understanding this important for dealing with global warming ?
|
mysteries of vernacular : yankee , a new england resident or , more generally , a person who lives in or is from the united states . though the origin of yankee is uncertain , this all-american word most likely descended from the dutch moniker janke , a diminutive meaning little jan , or little john . in the 17th century , janke was the common nickname of dutch sailors , pirates in particular . a dutch pirate ship operating in the west indies was even called the yankee . over the years , yankee transformed from a pirate 's nickname into a general term of contempt . in 1758 , british general james wolfe used yankee as a pejorative term for the colonists under his supervision . but the insult was n't limited to soldiers . yankee quickly came to mean new englander , and by the 1780s , it was used to look down upon any american . during the revolution , colonists co-opted yankee and transformed it into a mark of national honor . the civil war , however , intensified the derisive definition when it was used by southerners to mock members of the union . today , it carries much less emotion , unless , of course , we 're talking about baseball .
|
mysteries of vernacular : yankee , a new england resident or , more generally , a person who lives in or is from the united states . though the origin of yankee is uncertain , this all-american word most likely descended from the dutch moniker janke , a diminutive meaning little jan , or little john . in the 17th century , janke was the common nickname of dutch sailors , pirates in particular .
|
though yankee can refer to any u.s. resident , it is often used to describe a person from new england . how does this regional specificity relate to the history of the word and the american revolution ?
|
♪♪ when he was nine years old , ron , without my parents or myself knowing his whereabouts , decided to take a mile walk from our home down to the library , which was , of course , a public library , but not so public for black folks when you 're talking about 1959 . so as he was walking in there , all these folks were staring at him because it was white folk only and they were looking at him saying , you know , `` who is this negro ? '' so he politely positioned himself in line to check out his books . well , this old librarian , she says , `` this library 's not for coloreds . '' he said , `` well , i would like to check out these books . '' she says , `` young man , if you do n't leave this library right now , i 'm gon na call the police . '' so he just propped himself up on the counter ... ( laughs ) and sat there and said , `` i 'll wait . '' so , she called the police and subsequently called my mother . the police came down , two burly guys , come in and say , `` well , where 's the disturbance ? '' she pointed to the little nine year old boy sitting up on the counter . he says , `` ma'am , what 's the problem ? '' so my mother , in the meanwhile , she was called and she comes down there praying the whole way there , `` lordy , jesus , please do n't let them put my child in jail . '' and my mother asked the librarian , `` what 's the problem ? '' `` he wanted to check out the book . you know your son should n't be down here . '' and the police officer said , `` why do n't you just give the kid the books ? '' and my mother said , `` he 'll take good care of them . '' and reluctantly , the librarian gave ron the books . and my mother said , `` what do you say ? '' he said , `` thank you , ma'am . '' ( laughs ) later on , as youngsters , a show came on tv called , `` star trek . '' now , star trek showed the future where there were black folk and white folk working together , and i just looked at it as science-fiction , because that was n't gon na happen , really . but ronald saw it as science-possibility , you know . he came up during a time when there was neil armstrong and all of those guys . so how was a colored boy from south carolina , wearing glasses , who never flew a plane , how was he gon na become an astronaut ? but ron was the one who did n't accept societal norms as being his norm . that was for other people . and uh , he got to be aboard his own starship enterprise . ♪♪ closed captions by captionlink www.captionlink.com
|
so as he was walking in there , all these folks were staring at him because it was white folk only and they were looking at him saying , you know , `` who is this negro ? '' so he politely positioned himself in line to check out his books . well , this old librarian , she says , `` this library 's not for coloreds . '' he said , `` well , i would like to check out these books . '' she says , `` young man , if you do n't leave this library right now , i 'm gon na call the police . ''
|
how old was ronald mcnair when he tried to check out books from the library ?
|
what makes a book a book ? is it just anything that stores and communicates information ? or does it have to do with paper , binding , font , ink , its weight in your hands , the smell of the pages ? is this a book ? probably not . but is this ? to answer these questions , we need to go back to the start of the book as we know it and understand how these elements came together to make something more than the sum of their parts . the earliest object that we think of as a book is the codex , a stack of pages bound along one edge . but the real turning point in book history was johannes gutenberg 's printing press in the mid-15th century . the concept of moveable type had been invented much earlier in eastern culture , but the introduction of gutenberg 's press had a profound effect . suddenly , an elite class of monks and the ruling class no longer controlled the production of texts . messages could spread more easily , and copies could constantly be produced , so printing houses popped up all over europe . the product of this bibliographic boom is familiar to us in some respects , but markedly different in others . the skeleton of the book is paper , type , and cover . more than 2000 years ago , china invented paper as a writing surface , which was itself predated by egyptian papyrus . however , until the 16th century , europeans mainly wrote on thin sheets of wood and durable parchment made of stretched animal skins . eventually , the popularity of paper spread throughout europe , replacing parchment for most printings because it was less expensive in bulk . inks had been made by combining organic plant and animal dyes with water or wine , but since water does n't stick to metal type , use of the printing press required a change to oil-based ink . printers used black ink made of a mixture of lamp soot , turpentine , and walnut oil . and what about font size and type ? the earliest movable type pieces consisted of reversed letters cast in relief on the ends of lead alloy stocks . they were handmade and expensive , and the designs were as different as the people who carved their molds . standardization was not really possible until mass manufacturing and the creation of an accessible word processing system . as for style , we can thank nicolas jenson for developing two types of roman font that led to thousands of others , including the familiar times roman . something had to hold all this together , and until the late 15th century , covers consisted of either wood , or sheets of paper pasted together . these would eventually be replaced by rope fiber millboard , originally intended for high quality bindings in the late 17th century , but later as a less expensive option . and while today 's mass produced cover illustrations are marketing tools , the cover designs of early books were made to order . even spines have a history . initially , they were not considered aesthetically important , and the earliest ones were flat , rather than rounded . the flat form made the books easier to read by allowing the book to rest easily on a table . but those spines were damaged easily from the stresses of normal use . a rounded form solved that issue , although new problems arose , like having the book close in on itself . but flexibility was more important , especially for the on-the-go reader . as the book evolves and we replace bound texts with flat screens and electronic ink , are these objects and files really books ? does the feel of the cover or the smell of the paper add something crucial to the experience ? or does the magic live only within the words , no matter what their presentation ?
|
to answer these questions , we need to go back to the start of the book as we know it and understand how these elements came together to make something more than the sum of their parts . the earliest object that we think of as a book is the codex , a stack of pages bound along one edge . but the real turning point in book history was johannes gutenberg 's printing press in the mid-15th century .
|
what is a codex ?
|
you might remember a pair of ted-ed lessons written and performed by two educators , brad voytek and tim verstynen . these two scientists used a drooling , hag-faced , animated zombie as a mechanism to model the symptoms and medical diagnosis process for various neurological conditions . for example , they spent time debating whether the zombie 's stiff gait was caused by basal ganglia damage , like that in parkinson 's patients , or by severe damage to the cerebellum , which can cause ataxia . in each lesson , brad and tim certainly showed us how the walking dead can help us understand neuroscience , but how can the walking dead help us understand animation ? or , more simply put , how did this one-eyed , decaying , and very much dead pile of pixels walk ? puppet animation is a relatively quick solution to creating 2-d animation of a hand-drawn character . since the character does not need to be drawn over and over again , it can be animated by moving each element individually . aside from their portrayal in a few great modern zombie flicks , these concocted carcasses are generally known for limited , stiff movements . their traditional stride is perfect for puppet-style animation . when designing a 2-d zombie puppet , or any other type of puppet , it is important to find a design that is both fun and functional in a flat environment . for example , you might not want to puppetize , say , julie andrews in the `` sound of music '' as she spins in circles . we used rotoscoping for her , but that 's another lesson . always begin by sketching and designing your puppet in a neutral pose like this . this will allow it to easily transition into and out of a variety of extreme positions . once a character transitions from concept stetches to final design , the next step is to break up the pieces in order to assemble a puppet , keeping in mind that each element needs to have an appropriate amount of overlap so that the zombie can bend at his joints . an understanding of anatomy is an integral part of designing any 2-d or 3-d animated character that needs to move realistically in the context of its environment . regardless of the number of dimensions your character has , you 'll need to create a skeleton , which in animation terms is known as a rig . once the rig is finalized and the range of motion is determined , the next step is to choose anchor points . each piece of artwork has its own anchor point , which essentially assigns the limb a hinge , which in this case is a joint . next , line the artwork up so that the anchor point for the forearm-elbow sits on the upper arm 's elbow area . once all the artwork is in place , you can use an expression script that creates links between the body parts . in this case , we used the expressions provided in after effects . by parenting one layer to another , you could teach the forearm to follow the upper arm and the hand to follow the forearm . this is what 's called forward kinematics . the alternative is inverse kinematics , in which a separate set of scripts control the motions . in this case , a controller is attached to the anchor point of the hand . the animator then uses the controller to position the hand . the scripts will then use an algorithm to make sure that the rest of the arm and body follows along . once the character is rigged , we can start animating . often times , puppet animation is done as straight-ahead action , which means moving a character frame-by-frame from beginning to end . another approach is pose-to-pose animation , which involves choosing your key poses first , and then filling in the intervals , or in-betweens , later . regardless of the method of motion , it 's important to think of your 2-d puppet as a piece of paper . it can move across a surface in a variety of poses , but it can not move in perspective . if your character needs to turn its head , then you will need to create additional art . we created three different zombie heads and six different hands to achieve different movements and angles that the neutral pose could n't accommodate . you can recreate almost everything you 've seen in this lesson with a pen , paper , and a camera . the method is called cut-out animation , and it was around well before the age of software . to create a stumbling 2-d zombie , or a speeding narwhal , or even an abstract character with some semblance of joints , simply print , cut , and fasten your character 's limbs together in a neutral pose . you can use fasteners , string , or even just place and move them each time . all the same rules and theories that we use in the computer apply to cut-out animation , except under the camera , the only way to animate is straight ahead .
|
we used rotoscoping for her , but that 's another lesson . always begin by sketching and designing your puppet in a neutral pose like this . this will allow it to easily transition into and out of a variety of extreme positions .
|
always begin by sketching and designing your puppet in a ________ .
|
how does your smartphone know exactly where you are ? the answer lies 12,000 miles over your head in an orbiting satellite that keeps time to the beat of an atomic clock powered by quantum mechanics . phew . let 's break that down . first of all , why is it so important to know what time it is on a satellite when location is what we 're concerned about ? the first thing your phone needs to determine is how far it is from a satellite . each satellite constantly broadcasts radio signals that travel from space to your phone at the speed of light . your phone records the signal arrival time and uses it to calculate the distance to the satellite using the simple formula , distance = c x time , where c is the speed of light and time is how long the signal traveled . but there 's a problem . light is incredibly fast . if we were only able to calculate time to the nearest second , every location on earth , and far beyond , would seem to be the same distance from the satellite . so in order to calculate that distance to within a few dozen feet , we need the best clock ever invented . enter atomic clocks , some of which are so precise that they would not gain or lose a second even if they ran for the next 300 million years . atomic clocks work because of quantum physics . all clocks must have a constant frequency . in other words , a clock must carry out some repetitive action to mark off equivalent increments of time . just as a grandfather clock relies on the constant swinging back and forth of a pendulum under gravity , the tick tock of an atomic clock is maintained by the transition between two energy levels of an atom . this is where quantum physics comes into play . quantum mechanics says that atoms carry energy , but they ca n't take on just any arbitrary amount . instead , atomic energy is constrained to a precise set of levels . we call these quanta . as a simple analogy , think about driving a car onto a freeway . as you increase your speed , you would normally continuously go from , say , 20 miles/hour up to 70 miles/hour . now , if you had a quantum atomic car , you would n't accelerate in a linear fashion . instead , you would instantaneously jump , or transition , from one speed to the next . for an atom , when a transition occurs from one energy level to another , quantum mechanics says that the energy difference is equal to a characteristic frequency , multiplied by a constant , where the change in energy is equal to a number , called planck 's constant , times the frequency . that characteristic frequency is what we need to make our clock . gps satellites rely on cesium and rubidium atoms as frequency standards . in the case of cesium 133 , the characteristic clock frequency is 9,192,631,770 hz . that 's 9 billion cycles per second . that 's a really fast clock . no matter how skilled a clockmaker may be , every pendulum , wind-up mechanism and quartz crystal resonates at a slightly different frequency . however , every cesium 133 atom in the universe oscillates at the same exact frequency . so thanks to the atomic clock , we get a time reading accurate to within 1 billionth of a second , and a very precise measurement of the distance from that satellite . let 's ignore the fact that you 're almost definitely on earth . we now know that you 're at a fixed distance from the satellite . in other words , you 're somewhere on the surface of a sphere centered around the satellite . measure your distance from a second satellite and you get another overlapping sphere . keep doing that , and with just four measurements , and a little correction using einstein 's theory of relativity , you can pinpoint your location to exactly one point in space . so that 's all it takes : a multibillion-dollar network of satellites , oscillating cesium atoms , quantum mechanics , relativity , a smartphone , and you . no problem .
|
enter atomic clocks , some of which are so precise that they would not gain or lose a second even if they ran for the next 300 million years . atomic clocks work because of quantum physics . all clocks must have a constant frequency .
|
how do scientists build atomic clocks in a laboratory ?
|
so neil ’ s got a sample of sodium . sodium is a very reactive metal , it is stored under an oil to stop air or moisture getting on it - stop it oxidising , stop it reacting - and as you can see it is a very soft metal , so he is going to put his knife in and withdraw the lump of sodium , so there is about 2 kilos of sodium here , it 's a really quite large rod . so we are going to cut a small sample of the sodium and we are going to see if we can explore some of its chemistry . sodium is again a light metal , rather like lithium and it has a , a melting point about 96 degrees . so the sodium is a very , very shiny metal and as you can see as neil cuts some off , you can see the quite nice shiny material . it ’ s really quite beautiful . reacts very , very quickly with air and also with water , you form the oxide layer which is the white , or the hydroxide is the white crust on the outside . and many of you will know that if you drop sodium into water it reacts almost explosively . so we are going to go outside now , go get some even bigger reactions , with the alkali metals . this is a dog bowl which is stoneware , it is very hard , not likely to break , unless i drop it on my toes . this is sodium , the metal that we cut a minute ago and you can see there is quite a substantial amount of the sodium , and we are going to pop it into the water and see what we can do with the reaction . ok ? so here we have a bowl full of water and maybe , oh , a gram of sodium ? so let ’ s see what happens , see what this reaction ’ s like . so it is reacting really , really quite quickly and really violently with the water , and you can see it is fizzing around and it is generating lots and lots of hydrogen gas . and see now the heat from the reaction is burning away all of that hydrogen which is generating and you can see the orange sodium flame . that was um ? that was good that is a bit of , a chunk of molten sodium has come out of there mate . so , let ’ s burn that . oh , it ’ s on your camera . oh it is too ! sodium chloride is transparent through infrared light and so here we have got a sheet of sodium chloride that has been stuck on to a glass vessel so that you can have infrared light going through it . now this is a broken one , which my students have broken . is that bit , have you got a , we need a needle neil , or a pair of tweezers . so you can see here that these windows have been broken but you can see an interesting aspect of sodium chloride that when it breaks it forms cracks that form at right angles . why is that ? this is related to the structure of the atoms inside the crystal which are arranged in a sort of cubic arrangement . i have also got quite a nice crystal of sodium chloride over here which i don ’ t know if you can see has been turned into a table lamp . and if you switch it on it lights up . so this is just a mass of natural sodium chloride from under the ground somewhere , probably in cheshire or somewhere else like this where they have large underground salt mines , deposits . ok so we have got another lump of sodium , and you can see it ’ s really nice and shiny . ok ? so we are going to pop that into that big bucket of water . see what the chemical reaction is , ok ? so here we go ! so you can see again , see the orange sodium spectrum as the sodium is getting excited as the hydrogen is burning all that heat . whoa ! exciting ! that is brilliant . that is much better . so sodium and water , excellent reaction . that was great . i like sodium , because its symbol na was the nickname that my mother whose name was ena used to use when she was a child , she was known as na , so whenever i see sodium in the formula , i sort of feel a sort of warm motherly feeling from this .
|
oh it is too ! sodium chloride is transparent through infrared light and so here we have got a sheet of sodium chloride that has been stuck on to a glass vessel so that you can have infrared light going through it . now this is a broken one , which my students have broken .
|
in a sodium chloride crystal , how are the sodium and chloride ions arranged ?
|
the year was 1816 . europe and north america had just been through a devastating series of wars , and a slow recovery seemed to be underway , but nature had other plans . after two years of poor harvests , the spring brought heavy rains and cold , flooding the rivers and causing crop failures from the british isles to switzerland . while odd-colored snow fell in italy and hungary , famine , food riots and disease epidemics ensued . meanwhile , new england was blanketed by a strange fog that would not disperse as the ground remained frozen well into june . in what came to be known as `` the year without a summer , '' some thought the apocalypse had begun . a mood captured in lord byron 's poem `` darkness '' : `` i had a dream which was not all a dream . the bright sun was extinguish 'd , and the stars did wander darkling in the eternal space , rayless , and pathless , and the icy earth swung blind and blackening in the moonless air ; morn came and went -- and came , and brought no day . '' they had no way of knowing that the real source of their misfortunes had occurred a year ago thousands of miles away . the 1815 eruption of mount tambora on the indonesian island of sumbawa was what is known as a supervolcano , characterized by a volume of erupted material , many times greater than that of ordinary volcanoes . and while the popular image of volcanic destruction is molten rock engulfing the surrounding land , far greater devastation is caused by what remains in the air . volcanic ash , dispersed by wind , can blanket the sky for days , while toxic gases , such as sulfur dioxide , react in the stratosphere , blocking out solar radiation and drastically cooling the atmosphere below . the resulting volcanic winter , along with other effects such as acid rain , can effect multiple continents , disrupting natural cycles and annihilating the plant life on which other organisms , including humans , depend . releasing nearly 160 cubic kilometers of rock , ash and gas , the mount tambora eruption was the largest in recorded history , causing as many as 90,000 deaths . but previous eruptions have been even more deadly . the 1600 eruption of peru 's huaynaputina is likely to have triggered the russian famine , that killed nearly two million , while more ancient eruptions have been blamed for major world events , such as the fall of the chinese xia dynasty , the disappearance of the minoan civilization , and even a genetic bottleneck in human evolution that may have resulted from all but a few thousand human beings being wiped out 70,000 years ago . one of the most dangerous types of supervolcano is an explosive caldera , formed when a volcanic mountain collapses after an eruption so large that the now-empty magma chamber can no longer support its weight . but though the above-ground volcano is gone , the underground volcanic activity continues . with no method of release , magma and volcanic gases continue to accumulate and expand underground , building up pressure until a massive and violent explosion becomes inevitable . and one of the largest active volcanic calderas lies right under yellowstone national park . the last time it erupted , 650,000 years ago , it covered much of north america in nearly two meters of ash and rock . scientists are currently monitoring the world 's active volcanoes , and procedures for predicting eruptions , conducting evacuations and diverting lava flows have improved over the years . but the massive scale and global reach of a supervolcano means that for many people there would be nowhere to run . fortunately , the current data shows no evidence of such an eruption occurring in the next few thousand years . but the idea of a sudden and unavoidable civilization-destroying apocalypse caused by events half a globe away will remain a powerful and terrifying vision . less fictional than we would like to believe . `` the winds were withered in the stagnant air , and the clouds perish 'd ; darkness had no need of aid from them -- she was the universe . '' - lord byron
|
releasing nearly 160 cubic kilometers of rock , ash and gas , the mount tambora eruption was the largest in recorded history , causing as many as 90,000 deaths . but previous eruptions have been even more deadly . the 1600 eruption of peru 's huaynaputina is likely to have triggered the russian famine , that killed nearly two million , while more ancient eruptions have been blamed for major world events , such as the fall of the chinese xia dynasty , the disappearance of the minoan civilization , and even a genetic bottleneck in human evolution that may have resulted from all but a few thousand human beings being wiped out 70,000 years ago .
|
which aspect of a supervolcanic eruption makes it the most deadly ?
|
beatbox is the original instrument . it all comes from the voice . today , we 're going teach you the three basic sounds of beatbox , which make up the foundation of it . now , the `` kick '' is the kick drum on the bottom and it makes the loud bass sound . it sounds like this : ( beatboxes bass sound ) alright ? you hear that ? ( beatboxes bass sound ) how do you make that sound ? well , the way you make that sound is you take a `` p '' and you take a `` b '' and you mesh those two together and it 's going to give you what we refer to as the kick drum . pb ! pb ! pb ! so , alright , so you try this : pb ! pb ! excellent ! now , the next sound is the almighty snare sound . and the snare sound is basically taking a `` k '' and an `` a '' and putting those two sounds together . and it sounds like this : ka ! ka ! ka ! alright ? so just try that , really easy . ka ! ka ! ka ! now , the last sound is one of my favorite sounds . it 's the hi-hat . the hi-hat 's my favorite sound , because it 's always on the tip of your tongue . you basically take a `` t '' and an `` s '' and twist those two together , and it 's going to sound like this : ts ts , ts , ts . it 's great , right ? so , you put all those together and you can make some really amazing , wonderful music that you can do anywhere . we can make beats in the car , right ? so we can just drive through the city , making a beat . and it sounds a little something like this . let 's speak to them . ( beatboxing ) ( beatboxing ends ) alright , so that 's how you can actually speak to each other . now , those are really complex beat patterns , right ? so , we 'll do a few beat patterns with you and you repeat after me so you can begin to learn these sounds , alright ? so check this out : ( beatboxing ) [ pb ts ka ] [ pa ka ] ( beatboxing ) [ ts ka ts ka pb ] ( beatboxing ) [ pb ka ka pb ts ] ( beatboxing ) [ ts ts ka pb ] so we can take all of those different rhythms and sounds , and jam with each other by listening to each other , right ? so right now we 're just rolling around , we 're going to drop a phat beat , maybe see if we can find some friends . check this out ! ( beatboxing ) [ beatsynth 's mom ] [ pb ts ts ts ts ts ts ] [ pb ts ts ts ts ts ts ] [ pb ts ts ts ts ts ts ] [ pb ts ts ts ts ts ts ]
|
you hear that ? ( beatboxes bass sound ) how do you make that sound ? well , the way you make that sound is you take a `` p '' and you take a `` b '' and you mesh those two together and it 's going to give you what we refer to as the kick drum .
|
what 's the sound called that you get when you mesh a p and a b ?
|
translator : andrea mcdonough reviewer : jessica ruby olive oil is 100 % fat ; there 's nothing else in it . pancake mix , on the other hand , is only about 11 % fat . and , yet , olive oil is good for you , and pancake mix is not . why is that ? as it turns out , the amount of fat we eat does n't impact our weight or our cholesterol or our risk of heart disease nearly as much as what kind of fat we eat . but let 's back up : what is fat ? if we were to zoom in on a salmon , which is a fatty fish , past the organs , past the tissues , into the cells , we would see that the stuff we call fat is actually made up of molecules called triglycerides , and they are not all alike . here 's one example . those three carbons on the left , that 's glycerol . now , you can think of that as the backbone that holds the rest of the molecule together . the three long chains on the right are called fatty acids , and it 's subtle differences in the structures of these chains that determine whether a fat is , let 's say , solid or liquid ; whether or not it goes rancid quickly ; and , most importantly , how good or how bad it is for you . let 's take a look at some of these differences . one is length . fatty acids can be short or long . another , more important difference is the type of bond between the carbon atoms . some fatty acids have only single bonds . others have both single and double bonds . fatty acids with only single bonds are called saturated , and those with one or more double bonds are called unsaturated . now , most unsaturated fats are good for you , while saturated fats are bad for you in excess . for saturated fats , the story pretty much ends there but not for unsaturated fats . the double bonds in these molecules have a kind of weird property ; they 're rigid . so , that means there are two ways to arrange every double bond . the first is like this , where both hydrogens are on same side and both carbons are on the same side . the second way is like this . now the hydrogens and carbons are on opposite sides of the double bond . now , even though both of these molecules are made up of exactly the same building blocks , they are two completely different substances , and they behave completely differently inside of us . the configuration on the left is called cis , which you 've probably never heard of . the one of the right is called trans , and you probably have heard of trans fats before . they do n't go rancid , they 're more stable during deep frying , and they can change the texture of foods in ways that other fats just ca n't . they 're also terrible for your health , by far worse than saturated fat , even though technically they 're a type of unsaturated fat . now , i know that seems crazy , but your body does n't care what a molecule looks like on paper . all that matters is the 3-d shape where the molecule fits , where it does n't , and what pathways it interferes with . so , how do you know if a food has trans fat in it ? well , the only sure way to know is if you see the words , `` partially hydrogenated '' in the ingredients list . do n't let nutrition labels or advertising fool you . the fda allows manufacturers to claim that their products contain `` 0 '' grams of trans fat even if they actually have up to half a gram per serving . but there are no hard and fast rules about how small a serving can be , and , that means , you 'll have to rely on seeing those key words , partially hydrogenated , because that 's how trans fats are made , by partially hydrogenating unsaturated fats . so , let 's go back to our olive oil and pancake mix from before . olive oil is 100 % fat . pancake mix is only 11 % fat . but olive oil is mostly unsaturated fat , and it has no trans fat at all . on the other hand , more than half the fat in pancake mix is either saturated or trans fat . and , so , even though olive oil has 10 times as much fat as pancake mix , it 's healthy for you , whereas pancake mix is not . now , i 'm not trying to pick on pancake mix . there are lots of foods with this type of fat profile . the point is this : it 's not how much fat you eat , it 's what kind of fat . and what makes a particular fat healthy or unhealthy is its shape .
|
one is length . fatty acids can be short or long . another , more important difference is the type of bond between the carbon atoms .
|
triglycerides are composed of glycerol and ___ fatty acid chains .
|
on august 21 , 2017 the shadow of the moon will pass from the west coast to the east coast of the u.s. our blue sky will turn black as night and fill with stars , and there will be a hole in the sky where the sun used to be , surrounded by the fiery ring of the sun 's corona , a total eclipse of the sun . this will truly be a historic event . accounts of solar eclipses date way back on the written record . the early mesopotamians wrote that the sun was put to shame during the solar eclipse of the 14th century b.c.e . and it may have started the sun worship of the egyptian pharaoh akhenaten . ancient chinese astrologers paid with their lives if they failed to predict the solar eclipse and portend the fate of their emperors whose symbol was the sun . the earliest date of a specific event in human history , a battle between the armies of lydia and media , occurred on may 28 , 535 b.c.e . when a solar eclipse caused the soldiers to lay down their arms and declare a truce . so how does it happen ? during a total solar eclipse , the moon moves between the earth and the sun . when this happens , the disc of the moon appears to perfectly cover the disc of the sun even though the sun is much larger than the moon . but how is this possible ? the sun is 400 times bigger than the moon , but by sheer coincidence , the moon is 390 times closer to earth . size and distance cancel each other out so that the moon and sun appear to be almost the exactly same size . every time the moon orbits the earth , once every 27.3 days , it has to pass between the earth and the sun , a stage called the new moon phase . and every time it passes , the new moon has a chance to block out the sun . most of the time , the moon passes a little above or a little below the sun , but if they align perfectly , the shadow of the moon will make a narrow path across earth and those in the shadows will see a total solar eclipse . just like on night side of the earth , the sky during a total eclipse is black and filled with stars . but while the moon perfectly covers the surface of the sun , it does n't block out the sun 's outer atmosphere , its corona , which appears as a fiery ring around the dark disc of the moon . solar eclipses occur several times a year , but most often they are partial eclipses where the moon does n't quite line up with the sun . and , when the moon and sun are perfectly aligned , the moon is usually too far from earth in its orbit to completely cover the sun , creating an annular eclipse . during an annular or partial eclipse , the sky remains bright . even on those rare occasions of a total eclipse , the moon 's shadow is most likely to fall on the 70 % of earth that is covered by water , and few people , if any , will see it . the eclipse of 2017 will be remarkable on a larger scale because the moon is slowly moving away from earth . if a furry ancestor of ours had bothered to look up during a solar eclipse a hundred million years ago , it would n't have seen the fiery corona of the sun . it would have just been dark . eventually , the moon will have moved too far from earth to completely cover the disc of the sun . it is only during our little wink of earth 's history that the moon is at just the right distance to cause a total solar eclipse yet not block the sun 's corona . so on august 21 , 2017 , when the moon exactly lines up with the sun and the moon is close enough to the earth , its shadow will cross the u.s. and , if you happen to be in its narrow path , you will witness one of the most awe-inspiring sights in the universe . but , as incredible as this event will be , total eclipses are one of the most dangerous as well . only specially tinted filters , specifically designed to observe the sun , should be used . the eclipse might put the sun to shame , but even a shamed sun can seriously damage your eyes .
|
the earliest date of a specific event in human history , a battle between the armies of lydia and media , occurred on may 28 , 535 b.c.e . when a solar eclipse caused the soldiers to lay down their arms and declare a truce . so how does it happen ?
|
during which lunar phase does every solar eclipse occur ?
|
how 's this for a strange idea : a day off from work in honor of work itself ? actually , that is what labor day , celebrated in the united states and canada on the first monday of every september , is all about . the first american labor day was celebrated in new york city on september 5th , 1882 , as thousands of workers and their families came to union square for a day in the park . it was not a national holiday but had been organized by a union to honor workers and their hard efforts with a rare day of rest , halfway between july 4th and thanksgiving . there were picnics and a parade , but there were also protests . the workers had gathered , not just to rest and celebrate , but to demand fair wages , the end of child labor , and the right to organize into unions . during the period known as the industrial revolution , many jobs were difficult , dirty and dangerous . people worked for twelve hours , six days a week , without fringe benefits , such as vacations , health care and pensions , and if you were young , chances are you were doing manual labor instead of your abcs and fractions . children as young as ten worked in some of the most hazardous places , like coal mines or factories filled with boiling vats or dangerous machines . trying to win better pay , shorter hours and safer conditions workers had begun to form labor unions in america and canada , but the companies they worked for often fought hard to keep unions out and to supress strikes . at times , this led to violent battles between workers and business owners with the owners often backed up by the police , or even the military . in the following years , the idea of labor day caught on in america with official celebrations reaching 30 states . but then came the violent haymarket square riot of 1886 , which led to the deaths of several policemen and workers in chicago and the execution of four union leaders . after that , many labor and political groups around the world had begun to mark haymarket square on may 1st , which became known as international workers ' day . in 1894 , president grover cleveland signed the law making labor day a federal holiday in america , only days after he had sent 12,000 soldiers to end a violent railroad strike that resulted in the death of several people . the original september date was kept , partly to avoid the more radical associations of may 1st . canada also created its labor day in 1894 . but , in spite of this new holiday , it would be a long time before the changes that workers wanted became a reality . in 1938 , during the great depression that left millions without jobs , president franklin d. roosevelt signed a law calling for an eight-hour work day , a five-day work week , and an end to child labor , some of the first federal protections for american workers . as america and canada celebrate labor day , most of the two countries ' children enjoy a day off from school . but it is important to remember that there was a time that everyday was a labor day for children in america and canada , and unfortunately , the same fact remains true for millions of children around the world today .
|
but , in spite of this new holiday , it would be a long time before the changes that workers wanted became a reality . in 1938 , during the great depression that left millions without jobs , president franklin d. roosevelt signed a law calling for an eight-hour work day , a five-day work week , and an end to child labor , some of the first federal protections for american workers . as america and canada celebrate labor day , most of the two countries ' children enjoy a day off from school .
|
the american federal law ending child labor was signed into law in 1938 by president :
|
your brain on food if you sucked all of the moisture out of your brain and broke it down to its constituent nutritional content , what would it look like ? most of the weight of your dehydrated brain would come from fats , also known as lipids . in the remaining brain matter , you would find proteins and amino acids , traces of micronutrients , and glucose . the brain is , of course , more than just the sum of its nutritional parts , but each component does have a distinct impact on functioning , development , mood , and energy . so that post-lunch apathy , or late-night alertness you might be feeling , well , that could simply be the effects of food on your brain . of the fats in your brain , the superstars are omegas 3 and 6 . these essential fatty acids , which have been linked to preventing degenerative brain conditions , must come from our diets . so eating omega-rich foods , like nuts , seeds , and fatty fish , is crucial to the creation and maintenance of cell membranes . and while omegas are good fats for your brain , long-term consumption of other fats , like trans and saturated fats , may compromise brain health . meanwhile , proteins and amino acids , the building block nutrients of growth and development , manipulate how we feel and behave . amino acids contain the precursors to neurotransmitters , the chemical messengers that carry signals between neurons , affecting things like mood , sleep , attentiveness , and weight . they 're one of the reasons we might feel calm after eating a large plate of pasta , or more alert after a protein-rich meal . the complex combinations of compounds in food can stimulate brain cells to release mood-altering norepinephrine , dopamine , and serotonin . but getting to your brain cells is tricky , and amino acids have to compete for limited access . a diet with a range of foods helps maintain a balanced combination of brain messengers , and keeps your mood from getting skewed in one direction or the other . like the other organs in our bodies , our brains also benefit from a steady supply of micronutrients . antioxidants in fruits and vegetables strengthen the brain to fight off free radicals that destroy brain cells , enabling your brain to work well for a longer period of time . and without powerful micronutrients , like the vitamins b6 , b12 , and folic acid , our brains would be susceptible to brain disease and mental decline . trace amounts of the minerals iron , copper , zinc , and sodium are also fundamental to brain health and early cognitive development . in order for the brain to efficiently transform and synthesize these valuable nutrients , it needs fuel , and lots of it . while the human brain only makes up about 2 % of our body weight , it uses up to 20 % of our energy resources . most of this energy comes from carbohydrates that our body digests into glucose , or blood sugar . the frontal lobes are so sensitive to drops in glucose , in fact , that a change in mental function is one of the primary signals of nutrient deficiency . assuming that we are getting glucose regularly , how does the specific type of carbohydrates we eat affect our brains ? carbs come in three forms : starch , sugar , and fiber . while on most nutrition labels , they are all lumped into one total carb count , the ratio of the sugar and fiber subgroups to the whole amount affect how the body and brain respond . a high glycemic food , like white bread , causes a rapid release of glucose into the blood , and then comes the dip . blood sugar shoots down , and with it , our attention span and mood . on the other hand , oats , grains , and legumes have slower glucose release , enabling a steadier level of attentiveness . for sustained brain power , opting for a varied diet of nutrient-rich foods is critical . when it comes to what you bite , chew , and swallow , your choices have a direct and long-lasting effect on the most powerful organ in your body .
|
so eating omega-rich foods , like nuts , seeds , and fatty fish , is crucial to the creation and maintenance of cell membranes . and while omegas are good fats for your brain , long-term consumption of other fats , like trans and saturated fats , may compromise brain health . meanwhile , proteins and amino acids , the building block nutrients of growth and development , manipulate how we feel and behave .
|
why is glucose important for brain health ?
|
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 .
|
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 .
|
on average , compared with control participants , those who used a golf putter belonging to a champion , perceived the putting hole to be :
|
imagine yourself standing on a beach , looking out over the ocean , waves crashing against the shore , blue as far as your eyes can see . let it really sink in , the sheer scope and size of it all . now , ask yourself , `` how big is it ? how big is the ocean ? '' first thing , we need to understand that there really is only one ocean , consisting of five component basins that we call the pacific , the atlantic , the indian , the arctic , and the southern . each of these five , while generally referred to as oceans in and of themselves , are really and truly a part of a single , massive body of water , one ocean , which defines the very face of planet earth . the ocean covers roughly 71 % of our planet 's surface , some 360 million square kilometers , an area in excess of the size of 36 u.s.a. 's . it 's such a vast spread , when viewed from space , the ocean is , by far , the dominant feature of our planet . speaking of space , the ocean currently holds over 1.3 billion , that 's billion with a `` b '' , cubic kilometers of water . put another way , that 's enough water to immerse the entire united states under a body of salt water over 132 kilometers tall , a height well beyond the reach of the highest clouds and extending deep into the upper atmosphere . with all that volume , the ocean represents 97 % of earth 's total water content . on top of all that , the ocean contains upwards of 99 % of the world 's biosphere , that is , the spaces and places where life exists . now let that sink in for a second . the immediate world as we know it , indeed the totality of all the living space encompassed by the continents themselves , all of that represents only 1 % of the biosphere . 1 % ! the ocean is everything else . so , the ocean is physically massive . it 's importance to life is practically unparalleled . it also happens to hold the greatest geological features of our planet . quickly , here are four of the most notable . the ocean contains the world 's largest mountain range , the mid-ocean ridge . at roughly 65,000 kilometers long , this underwater range is some 10 times longer than the longest mountain chain found purely on dry land , the andes . beneath the denmark strait exists the world 's largest waterfall . this massive cataract carries roughly 116 times more water per second over its edge than the congo river 's inga falls , the largest waterfall by volume on land . the world 's tallest mountain is actually found in the ocean , hiding in plain sight . while 4200 meters of hawaii 's mauna kea sit above sea level , its sides plummet beneath the waves for another 5800 meters . from its snow-covered top to it 's silt-covered bottom , then , this hawaiian mountain is roughly 10,000 meters in height , dwarfing tiny everest 's paltry peak by well over a kilometer . then , since we 're picking on poor everest , let 's consider the world 's deepest canyon , the challenger deep , existing 11 kilometers below the ocean 's surface , some six times deeper than the grand canyon . that 's deep enough to sink mount everest into and still have over 2.1 kilometers of water sitting atop its newly submerged peak . put another way , the depth of the challenger deep is roughly the same height that commercial airliners travel . so , pretty much however you choose to slice it , the ocean is capital b capital i , capital g , big ! it defines our planet , home to the greatest geological features , comprises the largest living space , and accordingly , is home to the greatest numbers and forms of life on earth . it is practically incomprehensible in scope . but it is not so big , so vast , so extraordinary as to be untouchable . in fact , with roughly 50 % of the world 's population living within 100 kilometers of the coastline and with most of the remainder living close enough to lakes , rivers , or swamps , all of which ultimately lead to the ocean , virtually every single person on the planet has the opportunity to influence the general health and nature of the world ocean . evidence of human influence is seen in every part of the ocean , no matter how deep , no matter how distant . the ocean defines our planet , but , in a very real sense , we define the ocean .
|
put another way , that 's enough water to immerse the entire united states under a body of salt water over 132 kilometers tall , a height well beyond the reach of the highest clouds and extending deep into the upper atmosphere . with all that volume , the ocean represents 97 % of earth 's total water content . on top of all that , the ocean contains upwards of 99 % of the world 's biosphere , that is , the spaces and places where life exists .
|
in terms of both physicality and perspective , what influences support the existence of singular geologic features ( e.g . mauna kea , challenger deep , etc . ) within the earth ’ s ocean versus a continental setting ?
|
translator : tom carter reviewer : bedirhan cinar ( zombie sounds ) doctor 1 : so , how did it get to be this way ? doctor 2 : well , it 's my professional opinion that the large gaping bite mark on its shoulder might have something to do with it . d1 : thanks . i mean , what causes its behavioral abnormalities ? d2 : well , we know all behaviors are rooted in the brain , so i 'd expect that something 's gone terribly wrong probably in there . d1 : thanks again , doctor obvious . let me be more specific . what changes in the brain would have to occur in order to cause this kind of behavior ? d2 : hmm . well , let 's see . the first thing i notice is how it moves . stiff legged , with long , lumbering steps , very slow and awkward . almost like what you 'd see in parkinson 's disease . maybe something 's wrong with his basal ganglia ? those are a collection of deep brain regions that regulate movement , through a neurochemical called dopamine . although most people think of dopamine as the `` happy '' chemical of the brain , the dopamine-containing neurons in the basal ganglia die off in parkinson 's disease , that 's what causes it . makes it more and more difficult to initiate actions . d1 : what ? look again at how it moves . stiff legs , long stance , these are n't parkinsonian movements , parkinson 's patients take short , shuffling steps , and the posture 's all wrong . this looks to me like what happens when the cerebellum is damaged . the cerebellum 's a little cauliflower-shaped area in the back of your head , but do n't let its size fool you . that little guy contains almost half of the neurons in the entire brain . patients who suffer degeneration from this region , something called spino-cerebellar ataxia , show a lack of coordination that results in stiff legs , wide stance , and a lumbering walk . my money 's on the cerebellum . d2 : touché . ok . so we 've nailed its motor problems . now what about that whole groaning , lack of talking thing ? d1 : hmm . you know , it sounds kind of like expressive aphasia , or broca 's aphasia , which makes producing words difficult . this is caused by damage to the inferior frontal gyrus , or possibly the anterior insula , both regions behind your temple on the left side of your head . d2 : i think you 're only half right . zombies definitely ca n't communicate , that 's for sure . but they do n't seem to do a good job of understanding things either . watch this . hey , walker ! your father smelt of elderberries ! ( laughs ) see ? no reaction . either it 's not a monty python fan , or it ca n't understand me . i 'd say this is like spot-on fluent wernicke 's aphasia , damage to an area at the junction of two of the brain 's lobes , temporal and parietal , typically on the left side of the brain , is the culprit . this area is physically connected to broca 's area , that you mentioned , by a massive bundle of neurofibers called the arcuate fasciculus . i hypothesize that this massive bundle of connections is completely wiped out in a zombie . it would be like taking out the superhighway between two cities . one city that manufactures a product , and the other that ships it out to the rest of the world . without that highway , the product distribution just shuts down . d1 : so , basically it 's a moot point to reason with a zombie , since they ca n't understand you , let alone talk back . d2 : ( laughs ) i mean , you could try , man , but i 'm going to stay on this side of the glass .
|
stiff legged , with long , lumbering steps , very slow and awkward . almost like what you 'd see in parkinson 's disease . maybe something 's wrong with his basal ganglia ?
|
parkinson ’ s disease happens because cells that produce what chemical die off ?
|
translator : tom carter reviewer : bedirhan cinar the first 10 amendments to the u.s. constitution -- also known as the bill of rights -- were ratified or passed over 200 years ago . but even though they 're a bit , well , old , these first 10 amendments are still the most debated and discussed section of our constitution today . so , can you remember what they are ? let 's take a look . the first amendment is the freedom of speech , press , religion , assembly and petition . this may be the most revered of the amendments . the first amendment protects our rights to say and write our opinions , worship how we please , assemble together peacefully and petition our government , if we feel the need . the second amendment is the right to bear arms . the original intent of the second amendment was to protect colonists from the invading british soldiers , but it now guarantees that you have the right to own a gun to defend yourself and your property . the third amendment is called the `` quartering '' amendment . it was written in response to the british occupation , and as a result of the colonists having to house -- or quarter -- soldiers in their homes during the american revolution . because of this amendment , our government can never force us to house soldiers in our home . the fourth amendment is the right to search and seizure . the police ca n't come into our home without a search warrant and take our personal property . today , many concerns have arisen about our rights to privacy in technology . for example , can the government track your location with your smartphone , or can social media postings such as on facebook and twitter be used without a warrant ? on to the fifth : it 's all about due process . you 've probably heard the phrase `` i plead the fifth '' in movies or on tv . they 're talking about the fifth amendment , which says that you do n't have to take the witness stand against yourself if you may end up incriminating yourself . ok , we 're halfway done . the sixth and seventh amendments are about how the legal system works . if you 're accused of a crime , you have the right to a speedy public trial and an impartial jury . you also have the right to a lawyer , and the right to take the stand if you choose . this is important because it will prevent the accused from sitting in prison forever and insists that the prosecution proceed with undue delay . the seventh says you have the right to a jury trial , where 12 impartial peers decide your innocence or guilt in the courtroom , as opposed to a judge doing it all alone . the eight amendment prohibits cruel and unusual punishment . is the death penalty cruel ? is it unusual ? it 's hard for americans to agree on the definitions of cruel and unusual . the ninth and tenth amendments are called the non-rights amendments . they say that the rights not listed in the bill of rights are retained by the people in the states . we have other rights that are not listed in the constitution , and the states have the right to make their own policies , like instituting state taxes . so now you know all 10 amendments . can you remember them all ? if not , remember this : the bill of rights is a crucial piece of american history , and though society has undergone many changes these past 200 and some years , the interpretation and application of these amendments are as vital today as they were when they were written .
|
ok , we 're halfway done . the sixth and seventh amendments are about how the legal system works . if you 're accused of a crime , you have the right to a speedy public trial and an impartial jury .
|
the sixth and seventh amendments are about :
|
austrian physicist erwin schrödinger is one of the founders of quantum mechanics , but he 's most famous for something he never actually did : a thought experiment involving a cat . he imagined taking a cat and placing it in a sealed box with a device that had a 50 % chance of killing the cat in the next hour . at the end of that hour , he asked , `` what is the state of the cat ? '' common sense suggests that the cat is either alive or dead , but schrödinger pointed out that according to quantum physics , at the instant before the box is opened , the cat is equal parts alive and dead , at the same time . it 's only when the box is opened that we see a single definite state . until then , the cat is a blur of probability , half one thing and half the other . this seems absurd , which was schrödinger 's point . he found quantum physics so philosophically disturbing , that he abandoned the theory he had helped make and turned to writing about biology . as absurd as it may seem , though , schrödinger 's cat is very real . in fact , it 's essential . if it were n't possible for quantum objects to be in two states at once , the computer you 're using to watch this could n't exist . the quantum phenomenon of superposition is a consequence of the dual particle and wave nature of everything . in order for an object to have a wavelength , it must extend over some region of space , which means it occupies many positions at the same time . the wavelength of an object limited to a small region of space ca n't be perfectly defined , though . so it exists in many different wavelengths at the same time . we do n't see these wave properties for everyday objects because the wavelength decreases as the momentum increases . and a cat is relatively big and heavy . if we took a single atom and blew it up to the size of the solar system , the wavelength of a cat running from a physicist would be as small as an atom within that solar system . that 's far too small to detect , so we 'll never see wave behavior from a cat . a tiny particle , like an electron , though , can show dramatic evidence of its dual nature . if we shoot electrons one at a time at a set of two narrow slits cut in a barrier , each electron on the far side is detected at a single place at a specific instant , like a particle . but if you repeat this experiment many times , keeping track of all the individual detections , you 'll see them trace out a pattern that 's characteristic of wave behavior : a set of stripes - regions with many electrons separated by regions where there are none at all . block one of the slits and the stripes go away . this shows that the pattern is a result of each electron going through both slits at the same time . a single electron is n't choosing to go left or right but left and right simultaneously . this superposition of states also leads to modern technology . an electron near the nucleus of an atom exists in a spread out , wave-like orbit . bring two atoms close together , and the electrons do n't need to choose just one atom but are shared between them . this is how some chemical bonds form . an electron in a molecule is n't on just atom a or atom b , but a+ b . as you add more atoms , the electrons spread out more , shared between vast numbers of atoms at the same time . the electrons in a solid are n't bound to a particular atom but shared among all of them , extending over a large range of space . this gigantic superposition of states determines the ways electrons move through the material , whether it 's a conductor or an insulator or a semiconductor . understanding how electrons are shared among atoms allows us to precisely control the properties of semiconductor materials , like silicon . combining different semiconductors in the right way allows us to make transistors on a tiny scale , millions on a single computer chip . those chips and their spread out electrons power the computer you 're using to watch this video . an old joke says that the internet exists to allow the sharing of cat videos . at a very deep level , though , the internet owes its existance to an austrian physicist and his imaginary cat .
|
this superposition of states also leads to modern technology . an electron near the nucleus of an atom exists in a spread out , wave-like orbit . bring two atoms close together , and the electrons do n't need to choose just one atom but are shared between them . this is how some chemical bonds form .
|
an electron in the vicinity of two nearby atoms will be orbiting :
|
there 's a prevailing attitude that art does n't matter in the real world . but the study of art can enhance our perception and our ability to translate to others what we see . those skills are useful . those skills can save lives . doctors , nurses , and law enforcement agents can use painting , sculpture , and photography as tools to improve their visual acuity and communication skills , which are critical during investigations and emergencies . if you 're treating an injury , investigating a crime scene , or trying to describe either of those things to a colleague , art can make you better at it . here , imagine you 're a seasoned cop or a dedicated doctor , but also imagine you are at a museum and let 's look at a painting . rene magritte 's `` time transfixed '' of 1938 depicts a mysterious and complex interior that invites analysis not unlike that required of a patient 's symptoms or the scene of a crime . a miniature train whose origin and destination are unknown is emerging from a fireplace , and the smoke from the locomotive appears to flow up the chimney as if from the fire that is conspicuously absent below . the eeriness of the scene is echoed in the empty living room , enhanced by wood-grain floors and decorative wall moldings to the right of the fireplace . perched atop the mantelpiece are two candlesticks and a clock . behind these objects is a large mirror that reveals an empty interior and only a partial reflection of the objects before it . the juxtaposition of the objects surrounding the moving train raises numerous questions for which there seem to be no apparent answers . did i summarize the painting accurately or leave any details out ? it 's no big deal if you see something else in a painting , but what if we 're both seasoned cops ? i call you for back-up . you show up only to realize the two bank robbing ninjas i 'd mentioned were actually six bank robbing ninjas with lasers . close study of art can train viewers to study thoroughly , analyze the elements observed , articulate them succinctly , and formulate questions to address the seeming inconsistencies . scrutinizing the details of an unfamiliar scene , in this case the work of art , and accurately conveying any observable contradictions is a critically important skill for both people who look at x-rays and those who interrogate suspects . let 's interrogate this painting , shall we ? okay , magritte , that 's quite a little picture you 've painted . but why are n't there any train tracks ? why no fire ? what happened to the candles ? why does n't the fireplace have a little tunnel for the train ? it just comes straight through the wall . and the clock says it 's about quarter to one , but i 'm not sure the light that comes through the window at an angle says it 's just past noontime . what 's this painting all about , anyway ? that 's when you , my trusty partner , hold me back , then i leave . you give magritte a cup of coffee and keep grilling him to see if this painting would hold up in court . viewers can provide a more detailed and accurate description of a situation by articulating what is seen and what is not seen . this is particularly important in medicine . if an illness is evidenced by three symptoms and only two are present in a patient , a medical professional must explicitly state the absence of that third symptom , signifying that the patient may not have the condition suspected . articulating the absence of a specific detail or behavior known as the pertinent negative is as critical as stating the details and behaviors that are present in order to treat the patient . and conspicuous absences are only conspicuous to eyes trained to look for them . art teaches professionals across a wide spectrum of fields not only how to ask more effective questions about what can not be readily answered , but also , and more importantly , how to analyze complex , real world situations from a new and different perspective , ultimately solving difficult problems . intense attention to detail , the ability to take a step back and look differently , we want first responders to have the analytical skills of master art historians at least . art trains us to investigate , and that 's a real world skill if there ever was one .
|
if an illness is evidenced by three symptoms and only two are present in a patient , a medical professional must explicitly state the absence of that third symptom , signifying that the patient may not have the condition suspected . articulating the absence of a specific detail or behavior known as the pertinent negative is as critical as stating the details and behaviors that are present in order to treat the patient . and conspicuous absences are only conspicuous to eyes trained to look for them .
|
which of these is an example of the pertinent negative ?
|
sea turtles are miraculous . first , they 've been around since the late jurassic , roughly 150 million years ago . cohorts of the dinosaurs , sea turtles have survived through the challenges of eons , existing still today , where many others have ended their evolutionary run . second , throughout the centuries and up till today , every living adult sea turtle has overcome the odds , existing as a consequence of chance , skill , and capability . the gauntlet each sea turtle faces in the course of its lifetime goes thus : first , deposited as a clutch of leathery , ping-pong ball-sized eggs into a nesting pit dug by its mother high on the beach , of the 50 to 200 eggs laid , roughly 20 percent will never hatch . roughly a month and a half after having been laid , the surviving eggs hatch , and the young turtles , each small enough to fit in the palm of your hand , squirm to the surface , emerging from the sand en masse , and making their desperate dash for the sea . along the way , debris , pitfalls , crabs , gulls , raccoons , and other threats will claim roughly 50 percent of those who rose from the sand . for those that actually reach the surf , they trade one set of threats for another , as they first face the repelling force of the waves , and then find a whole new host of predators awaiting them : various fish , dolphins , sharks , and sea birds , as the young turtles come to the surface for air . for their first few days of life , should they count themselves amongst the living , the vulnerable turtles swim frantically forward . ultimately , they will often look to settle in a patch of flotsam , preferably a patch of floating seaweed . now for the next several months , they will seek to avoid those that would eat them , find that which they might eat themselves , and not fall to the pressures of challenging weather or unfortunate currents . in this phase , roughly 50 percent of those who reach the surf will perish . ultimately , with the passage of years , the survivors will increase in size , from that of a dinner plate at year one to that of a dinner table , in the case of one species at least , the leatherback , a decade or so later . with size comes some measure of protection . the only truly worrisome predators now are some of the larger shark species -- bulls , tigers , and whites -- and the occasional killer whale . at approximately two decades of age , the survivors will be old enough themselves to breed , and continue the cycle which their very existence heralds . of those that began as eggs on a distant beach , now less than 10 percent remain , at least , those were the odds prior to significant human interference . over the past century , and in particular in the last several decades , human endeavors , from beach development to plastic refuse to poaching , long lines , nets , and even noxious chemicals , including oil , have upped the ante for sea turtles , causing their survival rate to drop to around one percent or less , from each nesting cycle . it is this added human pressure which has pushed each of the eight sea turtle species into either a threatened or endangered state . for while they have evolved to overcome a host of obstacles , the most recent has arisen so quickly and at such scale that the species find themselves overwhelmed . so let 's quickly recap this cycle of odds . using a hypothetical nesting season , for females may nest multiple times in a single year , of 1,000 eggs , for sake of ease . 1000 eggs laid . 800 hatch . 400 make it to the water . 200 progress toward adulthood . 20 survive to breeding age -- that is , without human interference . two survive to breeding age with human interference . so a breeding adult sea turtle is the very embodiment of a long shot . it is the exception , not the rule . a jackpot . it is , in a very real sense , a miracle .
|
sea turtles are miraculous . first , they 've been around since the late jurassic , roughly 150 million years ago .
|
how long have sea turtles been around ?
|
translator : jessica ruby reviewer : caroline cristal they 're long and slithery , and they 're not very colorful . but they do have a strange beauty of their own . their sinuous , nocturnal movements through the water are mesmerizing to watch . and though they may resemble underwater snakes , eels are , in fact , a very interesting type of fish . there are several things about eels that make them unique besides their elongated shape and limbless bodies . for one thing , eels have the ability to breathe through their skin . some can even leave the water and move over land for short periods . and , unlike most migratory fish , such as salmon , which spawn in fresh water but live their adult lives in salt water , eels of the genus anguilla migrate in the opposite direction , spawning and breeding in oceans and seas , while spending most of their intervening time in fresh water . if we were to take one such fresh water eel and follow its life story , it would be born in the middle of the north atlantic ocean , about a thousand miles east of bermuda . this area , called the sargasso sea , forms the western part of a subtropical gyre , a giant whirlpool in the middle of the ocean . our eel , let 's call it eli , would begin as one of ten to twenty million tiny eggs , carried by a female eel , hatching into a transparent leaf-shaped thing that looks nothing like an adult eel . eli starts to drift in ocean currents , predominantly the gulf stream towards either europe or north america , depending on its particular species . upon reaching the coast , eli is about two inches long , looking more eely but still transparent , known at this stage as a glass eel . but within a couple of days in fresh water , eli 's skin becomes pigmented a brownish-black , now looking more like that of an adult eel . you might notice that we have n't mentioned anything about eli 's gender yet . that 's because this is only determined once an eel enters fresh water , though nobody is sure exactly how that happens . most of the eels that stay in the estuaries and brackish water become males , while those that go upstream become females , growing up to two to three times bigger than their future mates . in this case , it turns out that eli was actually short for elaine . as a female eel , elaine will be quite solitary for most of her life in the stream , eating whatever falls in the water : grasshoppers , crickets , small fish , insect larvae , frogs , baby birds , almost anything she can get her mouth around . and she will grow quite big , up to four feet long and weighing as much as thirteen pounds . we do n't know exactly how fresh water eels know when it 's time to return to the ocean , but something calls to them . and their fall migration is one of the largest unseen migrations on the planet . as elaine leaves fresh water for the ocean , she undergoes a shocking metamorphosis . her eyes enlarge by about ten times , her skin gets thicker , and her fins get larger . these are most likely adaptations for their upcoming ocean travel , and elaine seamlessly makes the transition from fresh to salt water , which would be toxic for most other fish . once elaine leaves the mouth of the fresh water streams , she will disappear completely from human view . no one has witnessed , or been able to follow , an adult eel on their migration , nor do we know how deep they spawn . but it 's assumed that they can follow some signs that they can detect , such as a thermal barrier between ocean currents or a salinity front , in order to return to the same area of the ocean where they were born . because we do n't even know exactly what happens during an eel 's migration , we can only imagine what the actual breeding looks like . but the common hypothesis is that elaine and thousands , or hundreds of thousands , of other eels gather in large , intertwined masses and release their eggs and sperm in a giant orgy known as panmixia . a couple of days after the eggs are laid , they hatch , and the cycle begins again . and because we 've never seen the adult eels returning up the fresh water rivers , we must assume that , having completed their long and roundabout journey , these amazing and mysterious creatures finally die there , in the same place where they were born . goodbye , elaine ! it was a pleasure knowing you .
|
her eyes enlarge by about ten times , her skin gets thicker , and her fins get larger . these are most likely adaptations for their upcoming ocean travel , and elaine seamlessly makes the transition from fresh to salt water , which would be toxic for most other fish . once elaine leaves the mouth of the fresh water streams , she will disappear completely from human view .
|
what would you imagine dams would do to migrating eels ?
|
take a moment to think about the us constitution . what 's the first thing that comes to mind ? freedom of speech ? protection from illegal searches ? the right to keep and bear arms ? these passages are cited so often that we can hardly imagine the document without them , but that 's exactly what the writers of the constitution did . the list of individual freedoms known as the bill of rights was not in the original text and was n't added for another three years . so does this mean the founders did n't consider them ? the answer goes back to the very origins of the constitution itself . even prior to the first shots of the american revolution , the thirteen colonies worked together through a provisional government called the continental congress . during the war in 1781 , the articles of confederation were ratified as the first truly national government . but establishing a new nation would prove easier than running it . congress had no power to make the states comply with their laws . when the national government proved unable to raise funds , enforce foreign treaties , or suppress rebellions , it was clear reform was needed . so in may 1787 , all the states but rhode island sent delegates to philidelphia for a constitutional convention . a majority of these delegates favored introducing a new national constitution to create a stronger federal government . thanks to compromises on issues like state representation , taxation power , and how to elect the president , their proposal gradually gained support . but the final text drafted in september still had to be approved by conventions held in the states . so over the next few months , ratification would be debated across the young nation . among those who championed the new document were leading statesmen alexander hamilton , james madison , and john jay . together , they laid out eloquent philosophical arguments for their positions in a series of 85 essays now known as the federalist papers . but others felt the constitution was overreaching and that more centralized authority would return the states to the sort of tyranny they had just escaped . these anti-federalists were especially worried by the text 's apparent lack of protections for individual liberties . as the conventions proceeded , many of these critics shifted from opposing the constitution entirely to insisting on adding an explicit declaration of rights . so what was the federalists problem with this idea ? while their opponents accused them of despotism , wanting to maintain absolute power in the central government , their real motives were mostly practical . changing the constitution when it had already been ratified by some states could complicate the entire process . more importantly , madison felt that people 's rights were already guaranteed through the democratic process , while adding extra provisions risked misinterpretation . and some feared that creating an explicit list of things the government ca n't do would imply that it can do everything else . after the first five states ratified the constitution quickly , the debate grew more intense . massachusetts and several other states would only ratify if they could propose their own amendments for consideration . leading federalists recognized the need to compromise and promised to give them due regard . once ratification by nine states finally brought the constitution into legal force , they made good on their promise . during a meeting of the first united states congress , representative james madison stood on the house floor to propose the very amendments he had previously believed to be unnecessary . after much debate and revision , first in the congress , and then in the states , ten amendments were ratified on december 15 , 1791 , over three years after the us constitution had become law . today , every sentence , word , and punctuation mark in the bill of rights is still considered fundamental to the freedoms americans enjoy , even though the original framers left them out .
|
what 's the first thing that comes to mind ? freedom of speech ? protection from illegal searches ?
|
given the understanding that the founding generation cherished freedom and liberty , how could they initially omit a bill of rights from the constitution ?
|
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.