context
stringlengths 241
19.4k
| questionsrc
stringlengths 34
2.9k
| question
stringlengths 11
1.46k
|
|---|---|---|
the constant thud underneath your feet , the constrained space , and the monotony of going nowhere fast . it feels like hours have gone by , but it 's only been eleven minutes , and you wonder , `` why am i torturing myself ? this thing has got to be considered a cruel and unusual punishment . '' actually , that 's exactly what it is , or was . you see , in the 1800s , treadmills were created to punish english prisoners . at the time , the english prison system was abysmally bad . execution and deportation were often the punishments of choice , and those who were locked away faced hours of solitude in filthy cells . so social movements led by religious groups , philanthropies , and celebrities , like charles dickens , sought to change these dire conditions and help reform the prisoners . when their movement succeeded , entire prisons were remodeled and new forms of rehabilitation , such as the treadmill , were introduced . here 's how the original version , invented in 1818 by english engineer sir william cubitt , worked . prisoners stepped on 24 spokes of a large paddle wheel . as the wheel turned , the prisoner was forced to keep stepping up or risk falling off , similar to modern stepper machines . meanwhile , the rotation made gears pump out water , crush grain , or power mills , which is where the name `` treadmill '' originated . these devices were seen as a fantastic way of whipping prisoners into shape , and that added benefit of powering mills helped to rebuild a british economy decimated by the napoleonic wars . it was a win for all concerned , except the prisoners . it 's estimated that , on average , prisoners spent six or so hours a day on treadmills , the equivalent of climbing 5,000 to 14,000 feet . 14,000 feet is roughly mount everest 's halfway point . imagine doing that five days a week with little food . cubitt 's idea quickly spread across the british empire and america . within a decade of its creation , over 50 english prisons boasted a treadmill , and america , a similar amount . unsurprisingly , the exertion combined with poor nutrition saw many prisoners suffer breakdowns and injuries , not that prison guards seemed to care . in 1824 , new york prison guard james hardie credited the device with taming his more boisterous inmates , writing that the `` monotonous steadiness , and not its severity ... constitutes its terror , '' a quote many still agree with . and treadmills lasted in england until the late 19th century , when they were banned for being excessively cruel under the prison 's act of 1898 . but of course the torture device returned with a vengeance , this time targeting the unsuspecting public . in 1911 , a treadmill patent was registered in the u.s. , and by 1952 , the forerunner for today 's modern treadmill had been created . when the jogging craze hit the u.s. in the 1970s , the treadmill was thrust back into the limelight as an easy and convenient way to improve aerobic fitness , and lose unwanted pounds , which , to be fair , it 's pretty good at doing . and the machine has maintained its popularity since . so the next time you voluntarily subject yourself to what was once a cruel and unusual punishment , just be glad you can control when you 'll hop off .
|
but of course the torture device returned with a vengeance , this time targeting the unsuspecting public . in 1911 , a treadmill patent was registered in the u.s. , and by 1952 , the forerunner for today 's modern treadmill had been created . when the jogging craze hit the u.s. in the 1970s , the treadmill was thrust back into the limelight as an easy and convenient way to improve aerobic fitness , and lose unwanted pounds , which , to be fair , it 's pretty good at doing .
|
what was the treadmill 's original purpose ?
|
when we talk about english , we often think of it as a single language but what do the dialects spoken in dozens of countries around the world have in common with each other , or with the writings of chaucer ? and how are any of them related to the strange words in beowulf ? the answer is that like most languages , english has evolved through generations of speakers , undergoing major changes over time . by undoing these changes , we can trace the language from the present day back to its ancient roots . while modern english shares many similar words with latin-derived romance languages , like french and spanish , most of those words were not originally part of it . instead , they started coming into the language with the norman invasion of england in 1066 . when the french-speaking normans conquered england and became its ruling class , they brought their speech with them , adding a massive amount of french and latin vocabulary to the english language previously spoken there . today , we call that language old english . this is the language of beowulf . it probably does n't look very familiar , but it might be more recognizable if you know some german . that 's because old english belongs to the germanic language family , first brought to the british isles in the 5th and 6th centuries by the angles , saxons , and jutes . the germanic dialects they spoke would become known as anglo-saxon . viking invaders in the 8th to 11th centuries added more borrowings from old norse into the mix . it may be hard to see the roots of modern english underneath all the words borrowed from french , latin , old norse and other languages . but comparative linguistics can help us by focusing on grammatical structure , patterns of sound changes , and certain core vocabulary . for example , after the 6th century , german words starting with `` p , '' systematically shifted to a `` pf '' sound while their old english counterparts kept the `` p '' unchanged . in another split , words that have `` sk '' sounds in swedish developed an `` sh '' sound in english . there are still some english words with `` sk , '' like `` skirt , '' and `` skull , '' but they 're direct borrowings from old norse that came after the `` sk '' to `` sh '' shift . these examples show us that just as the various romance languages descended from latin , english , swedish , german , and many other languages descended from their own common ancestor known as proto-germanic spoken around 500 b.c.e . because this historical language was never written down , we can only reconstruct it by comparing its descendants , which is possible thanks to the consistency of the changes . we can even use the same process to go back one step further , and trace the origins of proto-germanic to a language called proto-indo-european , spoken about 6000 years ago on the pontic steppe in modern day ukraine and russia . this is the reconstructed ancestor of the indo-european family that includes nearly all languages historically spoken in europe , as well as large parts of southern and western asia . and though it requires a bit more work , we can find the same systematic similarities , or correspondences , between related words in different indo-european branches . comparing english with latin , we see that english has `` t '' where latin has `` d '' , and `` f '' where latin has `` p '' at the start of words . some of english 's more distant relatives include hindi , persian and the celtic languages it displaced in what is now britain . proto-indo-european itself descended from an even more ancient language , but unfortunately , this is as far back as historical and archeological evidence will allow us to go . many mysteries remain just out of reach , such as whether there might be a link between indo-european and other major language families , and the nature of the languages spoken in europe prior to its arrival . but the amazing fact remains that nearly 3 billion people around the world , many of whom can not understand each other , are nevertheless speaking the same words shaped by 6000 years of history .
|
by undoing these changes , we can trace the language from the present day back to its ancient roots . while modern english shares many similar words with latin-derived romance languages , like french and spanish , most of those words were not originally part of it . instead , they started coming into the language with the norman invasion of england in 1066 .
|
english shares many words with _____ because of borrowing .
|
translator : andrea mcdonough reviewer : bedirhan cinar right now , trillions of chemical reactions are humming away in the cells of your body . you never feel them , but without these reactions , you would n't be alive . unfortunately , each of those reactions needs some help . you see , most molecules are stable , they are happy just the way they are . the atoms in them are all bound-up and friendly with one another and would prefer to stay that way . the problem is , for a chemical reaction to happen , the atoms that make up those stable molecules need to break away from their friends and go buddy up with another atom . this break-up is where the molecules need a hand . this initial kick-start is known as activation energy . it 's used to destabilize the molecule , to push the bonds between the atoms to a place where they are ready to break . this unstable state is known as the molecule 's transition state . once a transition state has been achieved , the atoms become willing to leave their current molecular friends and go make new friends elsewhere . once they are convinced , it 's a piece of cake . bonds break , atoms rearrange , and the rest of the reaction happens automatically . after that first push , the body does n't need to put in any more energy to help the reaction along . left alone , most of these reactions would be very slow because it takes quite a while to build up the activation energy the molecules need to get started . enter the enzyme . enzymes are proteins that speed up , or catalyze , reactions by lowering the activation energy . they make it easier for the molecule , also known as a substrate , to get to the transition state . you can think of a reaction like a race . some racers are running along , while others have teammates to help them . meet sam the substrate . his team is the mods squad . together , his team is able to get to the finish faster , using less energy . there are four special enzymes in sam 's team . each has a different strategy for lowering the energy it takes to get going and speeding up the pace to get the mods to the finish line . the `` m '' stands for `` microenvironment '' . this enzyme creates a tiny , special environment for the substrate , resulting in a faster reaction time . he runs ahead of the pack , flattening out bumps in the road and misting cool water on his team of molecules . `` o '' is for `` orientation '' . sometimes two molecules must be positioned just right before they will react . like a friend at the finish line , the o enzyme provides his molecules with specially shaped spaces that allow the substrates to interact in just the right way . `` d '' stands for `` direct participation '' . every now and again , a little muscle is needed . and when his teammates are struggling to finish the race , teammate d is there to pick them up and carry them over the line . finally , `` s '' is for `` straining bonds '' . this guy pushes the team through some serious flexibility exercises : splits , lunges , backbends , the works . sometimes his substrate teammates just need to be stressed and flexed into their transition state . so that 's it . remember that all reactions need energy to get going . this energy is known as the activation energy . enzymes lower that activation energy and speed the reaction through team mods : microenvironment , orientation , direct participation , and straining bonds .
|
meet sam the substrate . his team is the mods squad . together , his team is able to get to the finish faster , using less energy .
|
the mods are different types of ___ .
|
if you look at cars from the 1970s and cars from the 1990s , there ’ s really one big difference in their designs . the ones from the 70s are boxy , and the ones from the 90s are curvy . for some car models , you can even tell the exact year when that change happened . just look at this commercial for the buick lesabre , showing the 1991 model — and then the 1992 model . see the curves ? let ’ s watch that again . ‘ 91 is boxy , sharp edges . ‘ 92 ? smooth and round . since then , cars have become curvier and curvier . so how did this happen ? when manufacturers started making curvy cars in the 90s , it wasn ’ t a totally new concept . back in the 1930s , streamliners like this chrysler airflow used this sleek design to reduce wind resistance . but as the 50s and 60s rolled around , american streamliners stopped selling well — they were outsold by bigger , boxier cars . gas prices were on fairly steady decline at this point , so streamlining for fuel efficiency was less of a concern . well into the 1970s , just about every car made in america had sharp edges and very few curves . they were basically designed as a series of three boxes — the hood , the cabin , and the trunk . that model worked really well in the us market . but in europe , fuel was always more expensive . in the 60s , a gallon of gas in france cost a whopping 73.1 cents while it was just 31 cents in the us . so european designers started experimenting with more aerodynamic designs to help cars move more easily so they ’ d waste less gas . automakers like porsche , bmw , audi , mercedes-benz — they all started rolling out car models that had curved exteriors . eventually american automakers started to copy the european aerodynamic look to try to attract upscale consumers . the mass market was a different picture . in europe , a designer named uwe bahnsen was the first person to push for a curved design for the average driver , and he did that with the 1982 ford sierra . it was curvier than any car in its class at the time . but critics just laughed at it . and it did n't sell very well at first . it was nicknamed the “ jelly mould ” because of how much it looked like the kind of circular shape you ’ d make jell-o with . but one of the designers from that european ford design team — this guy , jack telnack — took over the us design team in 1980 . american gas prices at this point were skyrocketing due to conflict in the middle east . so telnack brought wind tunnel testing into the design process . he first did that with the 1983 ford thunderbird . but the real breakthrough came a few years later : `` the result was the groundbreaking 1986 ford taurus . '' it might not look that groundbreaking now , but this style was revolutionary at the time . it was a mass market car with curvy edges — and people liked it . “ taurus ! now a north american car with a shape and a feel we ’ ve never seen before… taurus for us ! ” they used it in robocop as the car of the future . the sales basically saved ford , which had really been struggling at the time , and it inspired a whole wave of copycat curvy cars . and streamlining became even more popular because manufacturers were facing new fuel economy regulations in the us . starting in 1978 , the average fuel efficiency of each manufacturer ’ s passenger cars had to meet higher and higher levels . according to one ford designer , aerodynamic design was a much more affordable way to boost efficiency than doing engineering work under the hood . the rise of computer modelling in the 80s also made it easier for car makers to design and manufacture curved lines . all these years later , the influence on today ’ s cars is pretty clear . even the models that we criticize for being ridiculously boxy these days — like the scion xb — are actually really round . and if our modern day sci fi movies have anything to say about it , that won ’ t be changing anytime soon .
|
according to one ford designer , aerodynamic design was a much more affordable way to boost efficiency than doing engineering work under the hood . the rise of computer modelling in the 80s also made it easier for car makers to design and manufacture curved lines . all these years later , the influence on today ’ s cars is pretty clear .
|
how did advances in computer modeling affect car designs ?
|
among the great poets of literary history , certain names like homer , shakespeare , milton , and whitman are instantly recognizable . however , there 's an early 20th century great french poet whose name you may not know : guillaume apollinaire . he was a close friend and collaborator of artists like picasso , rousseau , and chagall . he coined the term surrealism , and he was even suspected of stealing the mona lisa in 1911 . during his short lifetime , he created poetry that combined text and image in a way that seemingly predicted an artistic revolution to come . in the late 19th and early 20th century paris , the low-rent districts of montmartre and montparnasse were home to every kind of starving artist . it was all they could afford . these painters , writers , and intellectuals , united in their artistic passion and counterculture beliefs , made up france 's bohemian subculture . and their works of art , literature , and intellect would shake up the world . at the turn of the 20th century , within this dynamic scene , art critic , poet , and champion of the avant-garde , guillaume apollinaire was a well-known fixture . as an art critic , apollinaire explained the cubist and surrealist movements to the world , and rose to the defense of many young artists in the face of what was often a xenophobic and narrow-minded public . as a poet , apollinaire was passionate about all forms of art and a connoisseur of medieval literature , especially calligraphy and illuminated initials . as a visionary , apollinaire saw a gap between two artistic institutions . on one side was the popular , highly lauded traditional art forms of the time . on the other , the forms of artistic expression made possible through surrealism , cubism , and new inventions , like the cinema and the phonograph . within that divide , through the creation of his most important contribution to poetry , the calligram , guillaume apollinaire built a bridge . apollinaire created the calligram as a poem picture , a written portrait , a thoughts drawing , and he used it to express his modernism and his desire to push poetry beyond the normal bounds of text and verse and into the 20th century . some of his calligrams are funny , like the `` lettre-océan . '' some of them are dedicated to his young dead friends , like `` la colombe poignardée et le jet d'eau . '' some of them are the expression of an emotional moment , as is `` il pleut '' : `` it 's raining women 's voices as if they had died even in memory , and it 's raining you as well , marvellous encounters of my life , o little drops . those rearing clouds begin to neigh a whole universe of auricular cities . listen if it rains while regret and disdain weep to an ancient music . listen to the bonds fall off which hold you above and below . '' each calligram is intended to allow readers to unchain themselves from the regular experience of poetry , and feel and see something new . `` lettre-océan '' is first an image to be seen before even the words are read . text-only elements combine with words in shapes and forms . two circular forms , one locked in a square , the other , morph beyond the page in the shape of a spiral . together they create a picture that hints towards cubism . then on closer reading of the text , the descriptive words within suggest the image of an aerial view of the eiffel tower . they give tribute to electromagnetic waves of the telegraph , a new form of communication at the time . undoubtedly , the deeply layered artistic expressions in apollinaire 's calligrams are not just a brilliant display of poetic prowess from a master of the form . each calligram itself is also a snapshot in time , encapsulating the passion , the excitement , and the anticipation of all the bohemian artists of paris , including apollinaire , most of whom are well ahead of their time , and with their innovative work , eagerly grasping for the future .
|
on the other , the forms of artistic expression made possible through surrealism , cubism , and new inventions , like the cinema and the phonograph . within that divide , through the creation of his most important contribution to poetry , the calligram , guillaume apollinaire built a bridge . apollinaire created the calligram as a poem picture , a written portrait , a thoughts drawing , and he used it to express his modernism and his desire to push poetry beyond the normal bounds of text and verse and into the 20th century .
|
a calligram can be defined as :
|
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 .
|
that is much better . so sodium and water , excellent reaction . that was great .
|
considering the color of the sodium flame , what is the wavelength of the light emitted when sodium is burned ?
|
what if you could only see one color ? imagine , for instance , that you could only see things that were red and that everything else was completely invisible to you . as it turns out , that 's how you live your life all the time because your eyes can only see a minuscule part of the full spectrum of light . different kinds of light are all around you everyday but are invisible to the human eye , from the radio waves that carry your favorite songs , to the x-rays doctors use to see inside of you , to the microwaves that heat up your food . in order to understand how these can all be light , we 'll need to know a thing or two about what light is . light is electromagnetic radiation that acts like both a wave and a particle . light waves are kind of like waves on the ocean . there are big waves and small waves , waves that crash on the shore one right after the other , and waves that only roll in every so often . the size of a wave is called its wavelength , and how often it comes by is called its frequency . imagine being a boat in that ocean , bobbing up and down as the waves go by . if the waves that day have long wavelengths , they 'll make you bob only so often , or at a low frequency . if the waves , instead , have short wavelengths , they 'll be close together , and you 'll bob up and down much more often , at a high frequency . different kinds of light are all waves , they just have different wavelengths and frequencies . if you know the wavelength or frequency of a wave of light , you can also figure out its energy . long wavelengths have low energies , while short wavelengths have high energies . it 's easy to remember if you think about being in that boat . if you were out sailing on a day with short , choppy waves , you 'd probably be pretty high energy yourself , running around to keep things from falling over . but on a long wavelength sea , you 'd be rolling along , relaxed , low energy . the energy of light tells us how it will interact with matter , for example , the cells of our eyes . when we see , it 's because the energy of light stimulates a receptor in our eye called the retina . our retina are only sensitive to light with a very small range in energy , and so we call that range of light visible light . inside our retina are special receptors called rods and cones . the rods measure brightness , so we know how much light there is . the cones are in charge of what color of light we see because different cones are sensitive to different energies of light . some cones are more excited by light that is long wavelength and low energy , and other cones are more excited by short wavelength , high-energy light . when light hits our eye , the relative amount of energy each cone measures signals our brain to perceive colors . the rainbow we perceive is actually visible light in order of its energy . at one side of the rainbow is low-energy light we see as red , and at the other side is high-energy light we see as blue . if light shines on us that has an energy our retina ca n't measure , we wo n't be able to see it . light that is too short wavelength or high energy gets absorbed by the eye 's surface before it can even get to the retina , and light that is too long wavelength does n't have enough energy to stimulate our retina at all . the only thing that makes one kind of light different from another is its wavelength . radio waves have long wavelengths , while x-rays have short wavelengths . and visible light , the kind you can actually see , is somewhere in between . even though our eyes ca n't detect light outside of the visible range , we can build special detectors that are stimulated by these other wavelengths of light , kind of like digital eyes . with these devices , we can measure the light that is there , even though we ca n't see it ourselves . so , take a step back and think about all of this for a moment . even though they seem different , the warmth you feel from a crackling fire is the same as the sun shining on you on a beautiful day , the same as ultraviolet light you put on sunscreen to protect yourself from , the same thing as your tv , your radio , and your microwave . now , those examples are all things here on earth , things you experience in your everyday life , but here 's something even more amazing . our universe gives off the full spectrum of light , too . when you think of the night sky , you probably think of being able to see the stars shining with your own eyes , but that 's just visible light , which you now know is only a tiny part of the full spectrum . if we had to draw the universe and could only use visible light , it would be like having only one crayon -- pretty sad . to see the universe in its full spectrum , we need to have the right eyes , and that means using special telescopes that can help us see beyond visible light . you 've probably heard of the hubble space telescope and seen its beautiful pictures taken in visible and ultraviolet light . but you might not know that there are 20 space telescopes in orbit , missions that can each see part of the full spectrum of light . with telescopes acting as our virtual eyes , both in space and here on earth , we can see some amazing things . and the coolest thing of all , no matter the wavelength or energy , the light that we see out in the distant universe is the same thing as the light that we can experience and study here on earth . so , since we know the physics of how x-ray , ultraviolet light , or microwaves work here , we can study the light of a distant star or galaxy and know what kinds of things are happening there too . so , as you go about your daily life , think beyond what your eyes can and ca n't see . knowing just a little bit about the natural world can help you perceive the full spectrum around you all the time .
|
in order to understand how these can all be light , we 'll need to know a thing or two about what light is . light is electromagnetic radiation that acts like both a wave and a particle . light waves are kind of like waves on the ocean .
|
light is ________ that behaves like a wave and a particle .
|
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 .
|
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 harmfulness of a germ is called :
|
translator : jessica ruby reviewer : caroline cristal let 's say that it would take you ten minutes to solve this puzzle . how long would it take if you received constant electric shocks to your hands ? longer , right ? because the pain would distract you from the task . well , maybe not ; it depends on how you handle pain . some people are distracted by pain . it takes them longer to complete a task , and they do it less well . other people use tasks to distract themselves from pain , and those people actually do the task faster and better when they 're in pain than when they 're not . some people can just send their mind wandering to distract themselves from pain . how can different people be subjected to the exact same painful stimulus and yet experience the pain so differently ? and why does this matter ? first of all , what is pain ? pain is an unpleasant sensory and emotional experience , associated with actual or potential tissue damage . pain is something we experience , so it 's best measured by what you say it is . pain has an intensity ; you can describe it on a scale from zero , no pain , to ten , the most pain imaginable . but pain also has a character , like sharp , dull , burning , or aching . what exactly creates these perceptions of pain ? well , when you get hurt , special tissue damage-sensing nerve cells , called nociceptors , fire and send signals to the spinal cord and then up to the brain . processing work gets done by cells called neurons and glia . this is your grey matter . and brain superhighways carry information as electrical impulses from one area to another . this is your white matter . the superhighway that carries pain information from the spinal cord to the brain is our sensing pathway that ends in the cortex , a part of the brain that decides what to do with the pain signal . another system of interconnected brain cells called the salience network decides what to pay attention to . since pain can have serious consequences , the pain signal immediately activates the salience network . now , you 're paying attention . the brain also responds to the pain and has to cope with these pain signals . so , motor pathways are activated to take your hand off a hot stove , for example . but modulation networks are also activated that deliver endorphins and enkephalins , chemicals released when you 're in pain or during extreme exercise , creating the runner 's high . these chemical systems help regulate and reduce pain . all these networks and pathways work together to create your pain experience , to prevent further tissue damage , and help you to cope with pain . this system is similar for everyone , but the sensitivity and efficacy of these brain circuits determines how much you feel and cope with pain . this is why some people have greater pain than others and why some develop chronic pain that does not respond to treatment , while others respond well . variability in pain sensitivities is not so different than all kinds of variability in responses to other stimuli . like how some people love roller coasters , but other people suffer from terrible motion sickness . why does it matter that there is variability in our pain brain circuits ? well , there are many treatments for pain , targeting different systems . for mild pain , non-prescription medications can act on cells where the pain signals start . other stronger pain medicines and anesthetics work by reducing the activity in pain-sensing circuits or boosting our coping system , or endorphins . some people can cope with pain using methods that involve distraction , relaxation , meditation , yoga , or strategies that can be taught , like cognitive behavioral therapy . for some people who suffer from severe chronic pain , that is pain that does n't go away months after their injury should have healed , none of the regular treatments work . traditionally , medical science has been about testing treatments on large groups to determine what would help a majority of patients . but this has usually left out some who did n't benefit from the treatment or experienced side effects . now , new treatments that directly stimulate or block certain pain-sensing attention or modulation networks are being developed , along with ways to tailor them to individual patients , using tools like magnetic resonance imaging to map brain pathways . figuring out how your brain responds to pain is the key to finding the best treatment for you . that 's true personalized medicine .
|
what exactly creates these perceptions of pain ? well , when you get hurt , special tissue damage-sensing nerve cells , called nociceptors , fire and send signals to the spinal cord and then up to the brain . processing work gets done by cells called neurons and glia .
|
when you get hurt , ________ .
|
to understand climate change , think of the game `` tetris . '' for eons , earth has played a version of this game with blocks of carbon . they enter the atmosphere as carbon dioxide gas from volcanoes , decaying plant matter , breathing creatures and the surface of the sea . and they leave the atmosphere when they 're used by plants during photosynthesis , absorbed back into the ocean , or stored in soil and sediment . this game of tetris is called the carbon cycle , and it 's the engine of life on earth . what 's the connection to climate ? well , when that carbon dioxide is in the air , waiting to be reabsorbed , it traps a portion of the sun 's heat , which would otherwise escape to space . that 's why carbon dioxide is called a greenhouse gas . it creates a blanket of warmth , known as the greenhouse effect , that keeps our earth from freezing like mars . the more carbon dioxide blocks hang out in the atmosphere waiting to be cleared , the warmer earth becomes . though the amount of carbon in the atmosphere has varied through ice ages and astroid impacts , over the past 8,000 years the stable climate we know took shape , allowing human civilization to thrive . but about 200 years ago , we began digging up that old carbon that had been stored in the soil . these fossil fuels , coal , oil and natural gas are made from the buried remains of plants and animals that died long before humans evolved . the energy stored inside them was able to power our factories , cars and power plants . but burning these fuels also injected new carbon blocks into earth 's tetris game . at the same time , we cleared forests for agriculture , reducing the earth 's ability to remove the blocks . and since 1750 , the amount of carbon in the atmosophere has increased by 40 % , and shows no sign of slowing . just like in tetris , the more blocks pile up , the harder it becomes to restore stability . the extra carbon dioxide in the atmosphere accelerates the greenhouse effect by trapping more heat near the surface and causing polar ice caps to melt . and the more they melt , the less sunlight they 're able to reflect , making the oceans warm even faster . sea levels rise , coastal populations are threatened with flooding , natural ecosystems are disrupted , and the weather becomes more extreme over time . climate change may effect different people and places in different ways . but , ultimately , it 's a game that we 're all stuck playing . and unlike in tetris , we wo n't get a chance to start over and try again .
|
the extra carbon dioxide in the atmosphere accelerates the greenhouse effect by trapping more heat near the surface and causing polar ice caps to melt . and the more they melt , the less sunlight they 're able to reflect , making the oceans warm even faster . sea levels rise , coastal populations are threatened with flooding , natural ecosystems are disrupted , and the weather becomes more extreme over time .
|
melting ice causes earth to warm even further .
|
which is the hardest word to translate in this sentence ? `` know '' is easy to translate . `` pep rally '' does n't have a direct analog in a lot of languages and cultures , but can be approximated . but the hardest word there is actually one of the smallest : `` you . '' as simple as it seems , it 's often impossible to accurately translate `` you '' without knowing a lot more about the situation where it 's being said . to start with , how familiar are you with the person you 're talking to ? many cultures have different levels of formality . a close friend , someone much older or much younger , a stranger , a boss . these all may be slightly different `` you 's . '' in many languages , the pronoun reflects these differences through what 's known as the t–v distinction . in french , for example , you would say `` tu '' when talking to your friend at school , but `` vous '' when addressing your teacher . even english once had something similar . remember the old-timey `` thou ? '' ironically , it was actually the informal pronoun for people you 're close with , while `` you '' was the formal and polite version . that distinction was lost when the english decided to just be polite all the time . but the difficulty in translating `` you '' does n't end there . in languages like hausa or korana , the `` you '' form depends on the listener 's gender . in many more , it depends on whether they are one or many , such as with german `` du '' or `` ihr . '' even in english , some dialects use words like `` y'all '' or `` youse '' the same way . some plural forms , like the french `` vous '' and russian `` вы '' are also used for a single person to show that the addressee is that much more important , much like the royal `` we . '' and a few languages even have a specific form for addressing exactly two people , like slovenian `` vidva . '' if that was n't complicated enough , formality , number , and gender can all come into play at the same time . in spanish , `` tú '' is unisex informal singular , `` usted '' is unisex formal singular , `` vosotros '' is masculine informal plural , `` vosotras '' is feminine informal plural , and `` ustedes '' is the unisex formal plural . phew ! after all that , it may come as a relief that some languages often leave out the second person pronoun . in languages like romanian and portuguese , the pronoun can be dropped from sentences because it 's clearly implied by the way the verbs are conjugated . and in languages like korean , thai , and chinese , pronouns can be dropped without any grammatical hints . speakers often would rather have the listener guess the pronoun from context than use the wrong one and risk being seen as rude . so if you 're ever working as a translator and come across this sentence without any context : `` you and you , no , not you , you , your job is to translate 'you ' for yourselves '' ... well , good luck . and to the volunteer community who will be translating this video into multiple languages : sorry about that !
|
even english once had something similar . remember the old-timey `` thou ? '' ironically , it was actually the informal pronoun for people you 're close with , while `` you '' was the formal and polite version .
|
in shakespeare ’ s twelfth night , why does the character sir toby belch advise sir andrew aguecheek to use “ thou ” for his enemy , instead of “ you ” ?
|
have you ever heard the term , `` tip of the iceberg '' ? you know that icebergs are mostly underwater , their immense bulk hidden beneath the water . but why is that so ? well , the density of pure ice is less than that of sea water . usually only 1/9 of the volume of an iceberg is above the water . the shape of the underwater portion is difficult to discern by looking at the above-surface portion . this has led to the expression , `` tip of the iceberg . '' here are some thing you might not know about the icy islands . the life of an iceberg begins many thousands of years before it reaches the ocean . unlike sea ice or pack ice , which form when the ocean freezes , glaciers are made of fresh water . for thousands of years , these glaciers build layer upon layer of ice , constantly compressing , moving , adding snow , compressing , and moving again as they inch along like a frozen river . it is the force of gravity that pulls them towards the sea , where a glacier may calve off to become an iceberg or continue to spread up as an ice shelf or an ice tongue . once an iceberg breaks away from the glacier or ice shelf , it will usually live for three to six years , floating around , carried by the currents and tidal movements of the ocean . as it floats along , it is battered by waves , melts , and smashes into land and sometimes other icebergs . some icebergs are so unstable that they have more dramatic ends , heaving up , collapsing , and sometimes even exploding . and as they fall apart , many icebergs make all sorts of strange sounds . when a piece of iceberg melts , it makes a fizzing sound , called bergie seltzer . this sound is made when the water-ice interface reaches compressed air bubbles trapped in the ice . as this happens , each bubble bursts , making a popping sound . there are six official size classifications for icebergs . the smallest icebergs are called growlers . they can be up the size of your car and are very dangerous for ships and boats because usually they sit just at the waterline where they are not easy to spot . next are the bergy bits - yes , that is their scientific name - which can be up to the size of your home . the other four sizes are small , medium , large , and very large . so just how big is a very large iceberg ? officially , any iceberg looming larger than 270 feet high above sea level and 670 feet long is considered very large . that 's 27 stories of looming , blue ice . and how do icebergs get that blue color anyways ? when snow on the glacier is compressed over many hundreds of years , the weight of the snow forces the air bubbles out of the ice , creating pure ice with very little air trapped inside . this compression is seen when the glacier calves , creating a blue iceberg . an iceberg that has not experienced as much compression and has a large amount of air and surface edges reflects light as white . although they form in far northern or southern areas , icebergs can float thousands of miles . an iceberg from the arctic floated as far south as bermuda . antarctic icebergs are mostly trapped in the circumpolar current , never giving them a chance to float north . however , they have been known to interrupt shipping lanes between australia , south america , and south africa . for all their travelling , many people think that these slabs of ice are barren of life , but these seemingly sterile ice slabs also harbor their own complex ecosystems and they shape the ecosystems that they pass through . they become mobile , floating ecosystems . even in the coldest seas , icebergs are always melting , at least a little bit . this melting has a major impact on the ocean around an iceberg . the fresh water from the berg creates a pool of fresh water that can extend a nautical mile away from the iceberg . this water is colder than the surrounding sea water , and the temperature variation creates thermal currents in the vicinity of the iceberg . life thrives on and around an iceberg . young icefish hide in small ice holes to avoid predators , while a variety of invertebrates , like jellyfish and siphonophores , congregate in the area . many of them come to feed on krill , tiny shrimp-like creatures . snow petrels nest on the icebergs and feed on the sea life nearby . whales and seals and penguins seem to like them too . and even now that you know all this , we 're still at the tip of the iceberg . there are all sorts of things we do n't know about icebergs . perhaps you 'll be the one to see a little deeper .
|
here are some thing you might not know about the icy islands . the life of an iceberg begins many thousands of years before it reaches the ocean . unlike sea ice or pack ice , which form when the ocean freezes , glaciers are made of fresh water . for thousands of years , these glaciers build layer upon layer of ice , constantly compressing , moving , adding snow , compressing , and moving again as they inch along like a frozen river .
|
it takes many thousands of years for a glacier to reach the sea , calve off , and create an iceberg , yet only a few years for them to melt once they reach the ocean . why are icebergs causing sea level rise ? why doesn ’ t sea ice cause sea level rise ?
|
translator : tom carter reviewer : bedirhan cinar imagine a microscopic-sized ladder contained in the part of our brain that we 'll label our subconscious . the ladder of inference , which was first proposed by harvard professor chris argyris , is the basis of this model . every time we interact with someone , that experience enters the ladder at the bottom . that same experience zips up the ladder in the blink of an eye , exiting at the top . this process happens thousands of times a day without us knowing it . let 's focus on what happens on each rung of the ladder . on the first rung , we have the raw data and observations of our experience . this is very similar to what someone watching a video recording of our experience would see . moving up to the second rung , we filter in specific information and details from our experience . we unknowingly filter based on our preferences , tendencies , and many other aspects that we believe are important . on to the third rung . we assign meaning to the information we have filtered through . this is where we start to interpret what our information is telling us . on our fourth rung , a very crucial thing happens . we develop assumptions based on the meaning we created on the previous rung , and we start to blur the distinction between what is fact and what is story . on the fifth rung , we develop conclusions based on our assumptions . this is also where our emotional reactions are created . on the sixth rung , we adjust our beliefs about the world around us , including the person or people involved in our experience of the moment . on the seventh and final rung , we take action based on our adjusted beliefs . still with me ? great ! let 's take a real-life example and run it up the ladder to see how this all works . have you ever been cut off in a parking lot , signal light on as you steer toward your coveted spot , only to slam on your brakes at the last minute as someone pulls in front of you and steals your spot away ? imagine that experience and notice all of the data and observations landing on the first rung of your ladder . now let 's watch what we pay attention to on the second rung . who cares that it 's sunny out and the birds are chirping ? the 50 % off sign outside of your favorite store is meaningless . you filter in the sensation of your grip tightening on the wheel , you feel your blood pressure rise , you hear the squeal of your brakes , and you notice the expression on the face of the other driver as he pulls in front of you and quickly looks away . time for our third rung . ever since you were young , your parents taught you the importance of waiting in line and taking your turn . you live and die by the rule of first come , first served . and now this guy has just stolen your spot . what gives ? up to the fourth rung we go . watch closely as our assumptions take over and our story creates itself . `` that stupid jerk , did n't his parents teach him anything ? how could he not see my signal light ? he must never pay attention ! why does he think he 's more important than anyone else ? '' jumping quickly to the fifth rung , we conclude that this guy is heartless , inconsiderate , he needs to be taught a lesson and put in his place . we feel angry , frustrated , vindictive , justified . on our sixth rung , we adjust our beliefs based on the experience . `` that 's the last time i give in ! next time someone tries to cut me off , tires will be smoking on the pavement as i squeal past them into my spot . '' and finally our last rung : we take action . we back up , pull up behind his car , honk our horn , and roll down our window to scream a few choice words as well . now imagine , he walks over quickly , apologizing . his wife , who 's almost due with their first baby , called him from inside the mall to say she is in labor and needs to get to the hospital immediately . we 're momentarily shocked , apologize profusely , and wish him luck as he rushes toward the entrance . what just happened here ? what changed ? why is this so significant ? in our parking lot example , our beliefs were short-circuited by the ladder of the other individual . `` my wife is in labor , i need to get there quick , there 's a parking spot . whew ! oh , jeez , i cut someone off . i 'd better apologize quickly so they do n't think i 'm a jerk . '' but what if we were able to short-circuit our ladders ourselves ? proactively , by choice ? guess what ? we can ! let 's return to our unique human function of free will . next time you notice yourself reacting to your experience , pay focused attention to your ladder . ask yourself what beliefs are at play , where do they come from ? what data and observations did you filter in as a result of your beliefs , and why ? are your assumptions valid and supported by facts ? would a different set of assumptions create different feelings , and result in new and better conclusions and actions ? we all have our own unique ladder . be mindful of yours , and help others to see theirs .
|
translator : tom carter reviewer : bedirhan cinar imagine a microscopic-sized ladder contained in the part of our brain that we 'll label our subconscious . the ladder of inference , which was first proposed by harvard professor chris argyris , is the basis of this model . every time we interact with someone , that experience enters the ladder at the bottom . that same experience zips up the ladder in the blink of an eye , exiting at the top .
|
one of the most important pieces of awareness from the ladder of inference is how easily we can take on an identical pattern of response and behavior to somewhat similar ( but not identical ) experiences over time . what is a behavior pattern that you want to change ? how does the ladder of inference help you understand how to change this behavior pattern ?
|
the sight of mistletoe may either send you scurrying , or if you have your eye on someone , awaiting an opportunity beneath its snow white berries , but how did the festive christmas tradition of kissing under mistletoe come about ? the long-lived custom intertwines the mythology and biology of this intriguing plant . there are more than 1,000 species of mistletoe , which grows the world over . in fact , the ancient europeans were so captivated by the plant 's unusual growth habits that they included it in their legends and myths . in ancient rome , pliny the elder described how the druid priesthood in ancient england believed that mistletoe was a plant dropped down from heaven by the gods . that explained its unlikely position amongst the high branches of certain trees . they also believed it had powers of healing and bestowing fertility . meanwhile , scandinavian legend told of the plant 's mystical qualities in the story of the god baldr and his adoring mother frigg , goddess of love , marriage , and fertility . frigg loved her son so much that she commanded every plant , animal , and inanimate object to vow they 'd never harm him . in her fervor , however , she overlooked the mistletoe . the mischievous god loki realized this oversight and pierced baldr 's heart with an arrow carved from a mistletoe branch . frigg cried tears of such sadness that they formed the mistletoe 's pearly berries , making the other gods pity her and agree to resurrect baldr . hearing the news , frigg became so overjoyed that she transformed the mistletoe from a symbol of death into one of peace and love . she mandated a one-day truce for all fights , and that everyone embrace beneath its branches when they passed to spread more love into the world . in the 17th century , british colonists arriving in the new world found a different , but very similar looking , species of mistletoe . they applied it to these tales of magic , fertility , and love , spreading the mistletoe-hanging tradition from europe into america . by the 18th century , people in britain had turned this into a christmas tradition , but this custom comes down to more than just human imagination . all of it was inspired by the plant 's intriguing biology . we see mistletoe as a festive decoration , but draped on tree boughs in the wild , it 's known as a partly parasitic plant . mistletoe relies on modified roots called haustoria that penetrate the tree bark and siphon off the water and minerals trees carry up their trunks to colonize nearby trees with its seeds , mistletoe depends on birds and other creatures to do the dispersing . birds that eat the mistletoe 's sticky white berries sometimes get rid of the gluey seeds by wiping them off onto tree bark . or with a bit of luck , they excrete the indigestible seed onto a tree where it germinates and starts to grow . with its resilience and foliage that stays lush even while the surrounding trees lose their leaves , you can see why mistletoe captivated our superstitious ancestors . they saw these as signs of the plant 's magical qualities and fertility . even today , the mistletoe inspires wonder with the diversity of wildlife it supports . more than just a parasite , it 's also known as a keystone species . it 's eaten by a diversity of animals , including deer , elk , squirrels , chipmunks , porcupines , robins , bluebirds , morning doves , and the butterfly genus delias . some mistletoe species produce dense bushes , which are excellent nesting locations for a variety of birds . and despite their parasitic relationship with trees , mistletoes can also help other plants . for instance , juniper sprouts near mistletoe to benefit from the visiting berry-eating birds . through the many benefits it provides , mistletoe influences diversity , and allows ecosystems to flourish . you might even say that for this iconic plant , life imitates legend . in the wild , mistletoe has the power to bring things together , and in our own traditions , we see that happening , too .
|
in the 17th century , british colonists arriving in the new world found a different , but very similar looking , species of mistletoe . they applied it to these tales of magic , fertility , and love , spreading the mistletoe-hanging tradition from europe into america . by the 18th century , people in britain had turned this into a christmas tradition , but this custom comes down to more than just human imagination . all of it was inspired by the plant 's intriguing biology .
|
mistletoes are one good example of a pagan tradition that survived throughout time . can you think of any other common tradition with similar ancient roots ?
|
translator : andrea mcdonough reviewer : jessica ruby one of the reasons that i 'm fascinated by the ocean is that it 's really an alien world on our own planet . from our perspective , sitting on the shoreline or even out on a boat , we 're given only the tiniest glimpses at the real action that 's happening beneath the surface of the waves . and even if you were able to go down there , you would n't see very much because light does n't travel very far in the ocean . so , to answer questions about how the ocean works , in my research , we use sound . we use sonars that send out pulses of sound made up of a number of different frequencies , or pitches , that are shown with different colors . that sound bounces off things in the habitat and comes back to us . if it were to bounce off this dolphin , the signal we got back would look very much like the one we sent out where all the colors are represented pretty evenly . however , if we were to bounce that same sound off of a squid , which in this case is about the same size as that dolphin , we 'd instead only get the lowest frequencies back strongly , shown here in the red . and if we were to look at the prey of that squid , the tiny little krill that they 're eating , we would instead only get the highest frequencies back . and so by looking at this , we can tell what kinds of animals are in the ocean , we can look at how dense they are , where they are distributed , look at their interactions and even their behavior to start to study the ecology of the ocean . when we do that , we come up with something sort of surprising : on average , there is n't very much food in the ocean . so even in places which we think of as rich , the coasts , we 're talking about two parts of every million contain food . so what does that mean ? well , that means that in the volume of this theater , there would be one tub of movie theater popcorn available to be eaten . but of course , it would n't be collected for you neatly in this bucket . instead , you 'd actually have to be swimming through this entire volume willy wonka style , picking off individual kernels of popcorn , or perhaps if you were lucky , getting a hold of a few small clumps . but , of course , if you were in the ocean , this popcorn would n't be sitting here waiting for you to eat it . it would , instead , be trying to avoid becoming your dinner . so i want to know how do animals solve this challenge ? we 're going to talk about animals in the bering sea . this is where you may have see `` deadliest catch '' framed , in the northernmost part of the pacific ocean . we 've been looking specifically at krill , one of the most important food items in this habitat . these half-inch long shrimp-like critters are about the caloric equivalent of a heavily buttered kernel of popcorn . and they 're eaten by everything from birds and fur seals that pick them up one at a time to large whales that engulf them in huge mouthfuls . so i 'm going to focus in the area around three breeding colonies for birds and fur seals in the southeastern bering sea . and this is a map of that habitat that we made making maps of food the way we 've always made maps of food . this is how many krill are in this area of the ocean . red areas represent lots of krill and purple basically none . and you can see that around the northern two most islands , which are highlighted with white circles because they are so tiny , it looks like there 's a lot of food to be eaten . and yet , the fur seals and birds on these islands are crashing . their populations are declining despite decades of protection . and while on that southern island at the very bottom of the screen it does n't look like there 's anything to eat , those populations are doing incredibly well . so this left us with a dilemma . our observations of food do n't make any sense in the context of our observations of these animals . so we started to think about how we could do this differently . and this map shows not how many krill there are , but how many clumps of krill there are , how aggregated are they . and what you get is a very different picture of the landscape . now that southern island looks like a pretty good place to be , and when we combine this with other information about prey , it starts to explain the population observations . but we can also ask that question differently . we can have the animals tell us what 's important . by tagging and tracking these animals and looking at how they use this habitat , we are able to say , `` what matters to you ? '' about the prey . and what they 've told us is that how many krill there are really is n't important . it is how closely spaced those krill are because that 's how they are able to make a living . we see the same pattern when we look in very different ocean , further south in the pacific , in the warm waters around the hawaiian islands . so a very different habitat , and yet the same story . under some conditions , the physics and the nutrients , the fertilizer , set up aggregations in the plants , the phytoplankton . and when that happens , these very dense aggregations of phytoplankton attract their predators , which themselves form very dense layers . that changes the behavior and distribution of their predators as well , starting to set up how this entire ecosystem functions . finally , the predators that eat these small fish , shrimp , and squid , we 're talking about two- to three-inch long prey here , changes how they use their habitat and how they forage . and so we see changes in the spinner dolphins that are related to the changes we 're seeing in the plant life . and just by measuring the plants , we can actually predict very well what 's going to happen in the top predator three steps away in the food web . but what 's interesting is that even the densest aggregations of their prey are n't enough for spinner dolphins to make it . it 's a pretty tough life there in the ocean . so these animals actually work together to herd their prey into even denser aggregations , starting with patches that they find in the first place . and that 's what you 're going to see in this visualization . we have a group of 20 dolphins , you notice they 're all set up in pairs , that are working together to basically bulldoze prey to accumulate it on top of itself . and once they do that , they form a circle around that prey to maintain that really dense patch that is a couple thousand times higher density than the background that they started with before individual pairs of dolphins start to take turns feeding inside this circle of prey that they 've created . and so , this work is showing us that animals can first give us the answers that aggregation is critical to how they make their living . and by looking more deeply at the ocean , we 're starting to understand our interactions with it and finding more effective ways of conserving it . thank you .
|
and this is a map of that habitat that we made making maps of food the way we 've always made maps of food . this is how many krill are in this area of the ocean . red areas represent lots of krill and purple basically none . and you can see that around the northern two most islands , which are highlighted with white circles because they are so tiny , it looks like there 's a lot of food to be eaten .
|
which color ( s ) does the sonar return if it bounces off a group of krill ?
|
translator : ido dekkers reviewer : ariana bleau lugo ( music ) the basic question is , does life exist beyond earth ? scientists who are called astrobiologists are trying to find that out right now . most astrobiologists are trying to figure out if there 's microbial life on mars , or in the ocean under the frozen surface of jupiter 's moon europa , or in the liquid hydrocarbon lakes that we 've found on saturn 's moon titan . but one group of astrobiologists works on seti . seti is the search for extraterrestrial intelligence , and seti researchers are trying to detect some evidence that intelligent creatures elsewhere have used technology to build a transmitter of some sort . but how likely is it that they will manage to find a signal ? there are certainly no guarantees when it comes to seti , but something called the drake equation , named after frank drake , can help us organize our thinking about what might be required for successful detection . if you 've dealt with equations before , then you probably expect that there will be a solution to the equation , a right answer . the drake equation , however , is different , because there are so many unknowns . it has no right answer . as we learn more about our universe and our place within it , some of the unknowns get better known , and we can estimate an answer a bit better . but there wo n't be a definite answer to the drake equation until seti succeeds or something else proves that earthlings are the only intelligent species in our portion of the cosmos . in the meantime , it is really useful to consider the unknowns . the drake equation attempts to estimate the number of technological civilizations in the milky way galaxy -- we call that n -- with whom we could make contact , and it 's usually written as : n equals r-star multiplied by f-sub-p multiplied by n-sub-e multiplied by f-sub-l multiplied by f-sub-i multiplied by f-sub-c and lastly , multiplied by capital l. all those factors multiplied together help to estimate the number of technological civilizations that we might be able to detect right now . r-star is the rate at which stars have been born in the milky way galaxy over the last few billion years , so it 's a number that is stars per year . our galaxy is 10 billion years old , and early in its history stars formed at a different rate . all of the f-factors are fractions . each one must be less than or equal to one . f-sub-p is the fraction of stars that have planets . n-sub-e is the average number of habitable planets in any planetary system . f-sub-l is the fraction of planets on which life actually begins and f-sub-i is the fraction of all those life forms that develop intelligence . f-sub-c is the fraction of intelligent life that develops a civilization that decides to use some sort of transmitting technology . and finally , l -- the longevity factor . on average , how many years do those transmitters continue to operate ? astronomers are now almost able to tell us what the product of the first three terms is . we 're now finding exoplanets almost everywhere . the fractions dealing with life and intelligence and technological civilizations are ones that many , many experts ponder , but nobody knows for sure . so far , we only know of one place in the universe where life exists , and that 's right here on earth . in the next couple of decades , as we explore mars and europa and titan , the discovery of any kind of life there will mean that life will be abundant in the milky way . because if life originated twice within this one solar system , it means it was easy , and given similar conditions elsewhere , life will happen . so the number two is a very important number here . scientists , including seti researchers , often tend to make very crude estimates and acknowledge that there are very large uncertainties in these estimates , in order to make progress . we think we know that r-star and n-sub-e are both numbers that are closer to 10 than , say , to one , and all the f-factors are less than one . some of them may be much less than one . but of all these unknowns , the biggest unknown is l , so perhaps the most useful version of the drake equation is simply to say that n is approximately equal to l. the information in this equation is very clear . unless l is large , n will be small . but , you know , you can also turn that around . if seti succeeds in detecting a signal in the near future , after examining only a small portion of the stars in the milky way , then we learn that l , on average , must be large . otherwise , we could n't have succeeded so easily . a physicist named philip morrison summarizes by saying that seti is the archaeology of the future . by this , he meant that because the speed of light is finite , any signals detected from distant technologies will be telling us about their past by the time they reach us . but because l must be large for a successful detection , we also learn about our future , particularly that we can have a long future . we 've developed technologies that can send signals into space and humans to the moon , but we 've also developed technologies that can destroy the environment , that can wage war with weapons and biological terrorism . in the future , will our technology help stabilize our planet and our population , leading to a very long lifetime for us ? or will we destroy our world and its inhabitants after only a brief appearance on the cosmic stage ? i encourage you to consider the unknowns in this equation . why do n't you make your own estimates for these unknowns , and see what you come up with for n ? compare that with the estimates made by frank drake , carl sagan , other scientists or your neighbors . remember , there 's no right answer . not yet .
|
if you 've dealt with equations before , then you probably expect that there will be a solution to the equation , a right answer . the drake equation , however , is different , because there are so many unknowns . it has no right answer .
|
what makes the drake equation different from most other equations ?
|
`` barbecue '' ! ! the word derives from the word `` barabicu '' , which to the taíno people in the caribbean islands meant `` sacred fire pit '' . we are definitely on sacred ground today . if we can get in . [ music ] i 'm here to learn a little about the science of bbq , so i came to a man who knows a little bit about that , aaron franklin ... well that 's debatable . how 's it going ? so what is bbq ? i think bbq is something that 's cooked over a live fire , so that could encompass grilling , slow offset cooking , cooking in the ground , cooking whole hogs over coals , any of those kinds of things i call bbq , but for me on a personal level , it 's a german/czech style , offset cooking . '' i experiment all the time , at the end of the day feel trumps black and white number or equation you could possibly have . if something 's not tender , it 's just not tender , if something 's dry , it 's just too dry . but , the science behind these things how wood burns , how airflow works , if you start thinking about fluid dynamics inside of a cooker , then science has a pretty huge part of it . i think good bbq is a balance between science and natural gut instinct . cooking is really just thermodynamics and chemistry , but tastier . inside the smoker , air molecules are moving around really rapidly thanks to that fire , they 're vibrating all crazy , and when they smack into the brisket , they transfer that energy to the meat , either contributing chemical reactions or raising the temperature . meat browns when it cooks , whether it 's direct heat like a steak or slow like bbq . heat breaks proteins down into amino acids , which then react with sugars to create molecular deliciousness , which happens to be brown . it 's not caramelization , it 's something called the maillard reaction . king of bbq here in texas is brisket . it started out with whole animals , you would sell what you could and then whatever was left , as a method of preservation , you would bbq stuff on sundays for us to fully understand the science of bbq , we need to know a little about the hunk of meat we 're cooking . meat in general is muscle , which is primarily protein , fat , some vitamins and minerals , and whole lot of water . brisket comes from across chest area of cow , right here , and since cattle do n't have collarbones like us , this muscle has to support more than half their body weight . that means it 's got a lot of three things : hard-working muscle , fat , and connective tissue . it 's basically the opposite of filet mignon . but if we apply the right kind of science , those three things can come together like voltron to make something very tasty . so at the end of the day you want it to be tender , juicy , good bark , with good fat render . some of you might not want to hear this , but making good bbq is like making jell-o . ribs , brisket , pork shoulder , all cuts of meat that have tons of connective tissue , the molecular glue that supports all those muscle fibers . collagen , one of the proteins in connective tissue , can make up a quarter of all the protein in a mammal 's body . cook 'em fast , and those proteins snap up tight like rubber bands , they have the texture of them too . if you cook them slow , they melt . when collagen is heated slowly and held there for hours ( and hours ) , its long protein chains break down and water works its way in . that collagen turns to gelatin , exactly the same stuff that 's in this box . that 's what makes good bbq so tender inside . it 's meat jell-o . bbq cuts also have a good amount of fat . animal fats are made of triglycerides which have mostly saturated fatty acids . these have much higher melting points than unsaturated fats like , say , vegetable or olive oil you have in your kitchen , because those straight triglyceride tails are stable , packed nice and close . as we heat these saturated fats up , slowly , we can disrupt those hydrogen bonds and turn to liquid , called rendering . which is delicious . together , melting collagen to gelatin and liquefying fat make the meat oh so tender . you need no teeth to eat dis beef . what 's fun about an oven ? there 's nothing fun about ovens . did they have ovens back in the early days , coming up through mexico ? no you dug a hole in the ground , you buried a head , on coals , you cooked on a fire . and that 's where i 'm coming from more on the traditional side of it . i 'm not gon na use electricity , not gon na use gas no assisted heat source of any kind.we have light bulbs , and i do n't even like that so much . and it tastes good . that gets into a whole other thing too , how you 're using wood , green wood , dry wood , post oak , hickory , mesquite , pecan , any of these different kinds of woods they all taste different , they all cook different . the hardwoods used in bbq smoke have lots of cellulose and lignin . when burnt slowly , cellulose caramelizes into sugar molecules that flavor the meat . and lignin is converted into all kinds of aromatic chemicals that flavor the meat , and can even act as chemical preservatives . you just ca n't have brisket , or any bbq , without that beautiful smoke ring . now this is some cool chemistry ! or hot chemistry . meat starts out pink because it 's full of oxygen-carrying molecule called myoglobin . that iron-containing myoglobin starts out red , but as it heats up the iron in its heme group oxidizes and it turns this brown color . so why is the ring still red ? well , bbq smoke contains gases like carbon monoxide and nitric oxide , made by burning wood . that gas diffuse into the edges of the meat , bind to the myoglobin in place of oxygen . and those nitric oxide-myoglobin compounds just so happen to be pink . the edge stays nice and red while the interior gets brown like normal . kinda the art of working a fire is to control those things and get certain flavors out of a piece of wood . it 's not just heat , it 's not just the temperature on a gauge , it 's how the smoke is coming out of the smokestack , it 's how a piece of wood if it flames up and dies out real quick , it 's about a heat curve , how long is it gon na last , are you forcing a piece of wood to do something it does n't want to do ? you ca n't really make a piece of meat do what you want it to do , you can only guide it to do what you think you want it to do . so , kind of go with that , it 's all about trial and error , do n't give up , keep working on it . and if you really wanted to you could watch the bbq with franklin videos . out here we might have beer cans and aprons instead of test tubes and lab coats , but bbq is science , y'all . it 's chemistry , it 's physics , and the best part is you get to eat your experiments . stay curious . and hungry . i 'm gon na go get some food . special thanks to aaron franklin and the whole crew at franklin bbq . if you 're ever in austin , texas , line up early , because this is the best bbq joint in the us . seriously , you can look it up .
|
that 's what makes good bbq so tender inside . it 's meat jell-o . bbq cuts also have a good amount of fat .
|
what are two largest components of meat ?
|
translator : tom carter reviewer : bedirhan cinar this is the story of an invention that changed the world . imagine a machine that could cut 10 hours of work down to one . a machine so efficient that it would free up people to do other things , kind of like the personal computer . but the machine i 'm going to tell you about did none of this . in fact , it accomplished just the opposite . in the late 1700s , just as america was getting on its feet as a republic under the new u.s constitution , slavery was a tragic american fact of life . george washington and thomas jefferson both became president while owning slaves , knowing that this peculiar institution contradicted the ideals and principles for which they fought a revolution . but both men believed that slavery was going to die out as the 19th century dawned , they were , of course , tragically mistaken . the reason was an invention , a machine they probably told you about in elementary school : mr. eli whitney 's cotton gin . a yale graduate , 28-year-old whitney had come to south carolina to work as a tutor in 1793 . supposedly he was told by some local planters about the difficulty of cleaning cotton . separating the seeds from the cotton lint was tedious and time consuming . working by hand , a slave could clean about a pound of cotton a day . but the industrial revolution was underway , and the demand was increasing . large mills in great britain and new england were hungry for cotton to mass produce cloth . as the story was told , whitney had a `` eureka moment '' and invented the gin , short for engine . the truth is that the cotton gin already existed for centuries in small but inefficient forms . in 1794 , whitney simply improved upon the existing gins and then patented his `` invention '' : a small machine that employed a set of cones that could separate seeds from lint mechanically , as a crank was turned . with it , a single worker could eventually clean from 300 to one thousand pounds of cotton a day . in 1790 , about 3,000 bales of cotton were produced in america each year . a bale was equal to about 500 pounds . by 1801 , with the spread of the cotton gin , cotton production grew to 100 thousand bales a year . after the destructions of the war of 1812 , production reached 400 thousand bales a year . as america was expanding through the land acquired in the louisiana purchase of 1803 , yearly production exploded to four million bales . cotton was king . it exceeded the value of all other american products combined , about three fifths of america 's economic output . but instead of reducing the need for labor , the cotton gin propelled it , as more slaves were needed to plant and harvest king cotton . the cotton gin and the demand of northern and english factories re-charted the course of american slavery . in 1790 , america 's first official census counted nearly 700 thousand slaves . by 1810 , two years after the slave trade was banned in america , the number had shot up to more than one million . during the next 50 years , that number exploded to nearly four million slaves in 1860 , the eve of the civil war . as for whitney , he suffered the fate of many an inventor . despite his patent , other planters easily built copies of his machine , or made improvements of their own . you might say his design was pirated . whitney made very little money from the device that transformed america . but to the bigger picture , and the larger questions . what should we make of the cotton gin ? history has proven that inventions can be double-edged swords . they often carry unintended consequences . the factories of the industrial revolution spurred innovation and an economic boom in america . but they also depended on child labor , and led to tragedies like the triangle shirtwaist fire that killed more than 100 women in 1911 . disposable diapers made life easy for parents , but they killed off diaper delivery services . and do we want landfills overwhelmed by dirty diapers ? and of course , einstein 's extraordinary equation opened a world of possibilities . but what if one of them is hiroshima ?
|
separating the seeds from the cotton lint was tedious and time consuming . working by hand , a slave could clean about a pound of cotton a day . but the industrial revolution was underway , and the demand was increasing .
|
according to davis , a person could clean how much cotton by hand in a day ?
|
( music ) the eight traits successful people have in common . number one : passion . successful people love what they do . when i asked russell crowe what led to his academy award for best actor , he said , `` the bottom line is i love the actual job of acting . i have a great passion for it . '' successful people in all fields love what they do , whether it 's astrophysicist jaymie matthews , author j.k. rowling or athlete michael phelps . and not just big names -- margaret macmillan , a history professor , says , `` i spent my life doing what i loved . '' carlos , a bus driver i sit with at starbucks , says , `` i love what i do . i 've only missed three days in four years . '' and believe it or not , even successful dentists love what they do . izzy novak says , `` i love dentistry . i ca n't imagine being anything else . '' but what about business ? many of you are in business , and we tend to think that business is more about cold numbers than hot passion , more about logic than love , so what surprised me was how often successful business people actually use the words `` passion '' or `` love '' when they talk about their work . when jack welch was ceo of general electric , he was asked if he liked his job . he said , `` no , i do n't like this job . i love this job . '' we can have passion for a profession . kathleen lane , chief strategist at workcar , says , `` i 've found a profession i love . '' she also says , `` stress is n't working 15 hours at a job you like , stress is working 15 minutes at a job you dislike . '' we can have a passion for people . nez hallett iii , ceo of smart wireless , says , `` i used to be in sales . now i 'm a ceo . i just love being around people . '' we can have passion for a product . james dyson , the vacuum cleaner guy , says , `` i love vacuum cleaners , and i will love them until the day i die . '' ( laughter ) yup , when he dies , they 're just going to cremate him and suck up those ashes with a dyson vacuum , and place it on the shelf . ( laughter ) we can have passion for a particular field . anita roddick , the great founder of the body shop , once said , `` i love retailing . i love buying and selling and making connections . '' she also said , `` i do n't like systems , financial sheets or plans . '' yes , no matter how much we love what we do , there 's always going to be stuff we do n't love . the trick is to make sure the stuff you do n't love only takes up 20 percent of your time , and the stuff you do love takes up 80 . if it 's the other way around , we 're in the wrong job . passion is sometimes mistaken for ambition . people call donald trump ambitious , but he says , `` i 'm not ambitious . i just love what i do . and if you love what you do , you do a lot of stuff . and then people say , 'oh , you 're ambitious . ' '' the cool thing about passion is it turns underachievers into superachievers . i have a long list of famous underachievers -- like albert einstein -- who people said would go nowhere when they were young . for instance , who said this , besides me ? `` i was sitting in my room being a depressed guy , trying to figure out what i was doing with my life . '' turns out it was bill gates . bill was such an underachiever , his parents actually sent him to counseling . yeah , i can just hear the neighbors back then saying , `` jeez , that gates kid . what a loser . he 's never going to go anywhere . '' and he did n't , until he discovered his passion for software . the big problem is finding your passion . sure , there 's the kid that knows they want to be an accountant or an architect or an astronaut from the time they 're 10 , but i found a much bigger group of successful people who , when they were young , and even when they were older , did n't have a clue what their passion was , and it took them a long time to find it or to fall into it . dawn lepore , chief information officer at charles schwab , said to me , `` i fell into what i do , and i did n't know i loved it until i fell into it . '' and i hear that a lot . so how do people find their passion ? well they just get out there and try a lot of stuff and explore many paths . robert munsch explored many paths . he said to me , `` i studied to be a priest and that turned out to be a disaster . i tried working on a farm . they did n't like me . i worked on a boat . it sank . i tried a lot of things that did n't work , but i kept trying and then i tried something that did work . '' and i 'd say it worked ; as a children 's author , he 's sold over 40 million books . yes , finding a job we love is like finding a person we love . sometimes we 've just got to go on a lot of really bad dates before we find the right one . now , i read a survey of 18- to 25-year-olds , and 81 percent said their first or second life goal was to get rich . and i thought , boy , they 've got it all wrong . because i 've interviewed many millionaires and billionaires , and guess how many of them said their life goal was to get rich ? zero ! they did n't do it for money , they did it for love . they went for the zing , not the ka-ching ka-ching . when bill gates and paul allen started microsoft , they did n't do it for the money . bill says , `` paul and i never thought we 'd make much money . we just loved writing software . '' and with that attitude , he became the richest man in the world . j.k. rowling did n't write harry potter books for the money . she said , `` i love writing these books . i just wanted to make enough money to continue to write . '' and with that attitude , she became a billionaire . i became a millionaire by following my heart , not my wallet , and a number of times i walked away from great-paying jobs to do poor-paying jobs i loved better . once was when i had a great job , traveling the world , making a lot of money , but i was n't doing the one thing i loved at the time , which was photography . so i said , i think i 'll leave and start my own little photo company . my heart said , yeah ! go for it . my wallet , and all my friends , i might add , said , are you crazy ? you ca n't walk away from all the money ! you 'll starve . i did n't listen to them . i walked away , and yeah , at first there was n't much money , but it did n't matter , because i was having fun doing what i loved . and eventually , the money came , and much more than if i 'd stayed in my old job . so i learned it 's true , what they say : if you do what you love , the money comes anyway . so i 'd say if you really want to get rich , put money at the bottom of your goals list and passion at the top . and why does it work that way ? because if you love what you do , you automatically do the other seven things that lead to success and wealth . you will work hard , you will push yourself , you will persist . and what if you 're in a job you do n't love ? well , just follow your passion on the side . remember , albert einstein was a patent clerk . that was his job , but his passion was physics . and he wrote four of his most important papers in his spare time as a hobby , and became one of the world 's greatest scientists . so it 's amazing what you can do if you love what you do . ( applause )
|
i love buying and selling and making connections . '' she also said , `` i do n't like systems , financial sheets or plans . '' yes , no matter how much we love what we do , there 's always going to be stuff we do n't love .
|
anita roddick said she loved retailing , but she didn ’ t like `` systems , financial sheets or plans . '' there will always be stuff we don ’ t like , but have to do . 1 ) what stuff do you not like to do ? 2 ) are you spending 80 percent of your time on what you love , or 80 percent on the stuff you don ’ t like ? 3 ) think of ways you can spend more time doing what you love and write them down .
|
is there a disease that makes us love cats , and do you have it ? maybe , and it 's more likely than you 'd think . we 're talking about toxoplasmosis , a disease caused by toxoplasma gondii . like all parasites , toxoplasma lives at the expense of its host , and needs its host to produce offspring . to do that , toxo orchestrates a brain manipulation scheme involving cats , their rodent prey , and virtually all other birds and mammals , including humans . documented human infections go as far back as ancient egypt . we found samples in mummies . today , about a third of the world 's population is infected , and most of them never even know it . in healthy people , symptoms often do n't show up at all . when they do , they 're mild and flu-like . but those are just the physical symptoms . toxoplasma also nestles into our brains and meddles with our behavior behind the scenes . to understand why , let 's take a look at the parasite 's life cycle . while the parasite can multiply in practically any host , it can only reproduce sexually in the intestines of cats . the offspring , called oocysts , are shed in the cat 's feces . a single cat can shed up to a hundred million oocysts . if another animal , like a mouse , accidentally ingests them , they 'll invade the mouse 's tissues and mature to form tissue cysts . if the mouse gets eaten by a cat , the tissue cysts become active and release offspring that mate to form new oocysts , completing the cycle . but there 's a problem . a mouse 's natural desire to avoid a cat makes it tough to close this loop . toxoplasma has a solution for that . the parasites invade white blood cells to hitch a ride to the brain where they seem to override the innate fear of predators . infected rodents are more reckless and have slower reaction times . strangest of all , they 're actually attracted to feline urine , which probably makes them more likely to cross paths with a cat and help the parasite complete its life cycle . how does the parasite pull this off ? although the exact mechanism is n't known , toxo appears to increase dopamine , a brain neurotransmitter that is involved in novelty-seeking behavior . thus , one idea is that toxo tinkers with neurotransmitters , the chemical signals that modulate emotions . the result ? fatal attraction . but mice are n't the only animals that end up with these parasites , and that 's where humans , and all of toxo 's other hosts , come in . we can accidentally ingest oocysts in contaminated water , or unwashed produce , or from playing in sandboxes , or cleaning out litter boxes . this is behind the common recommendation that pregnant women not change cat litter . toxo can cause serious birth defects . we can also get toxo from eating undercooked meat from other animals that picked up some oocysts . and it turns out that toxo can mess with our brains , too . studies have found connections between toxo and schizophrenia , biopolar disorder , obsessive compulsive disorder , and aggression . it also slows reactions and decreases concentration , which may be why one study found that people involved in traffic accidents were almost three times more likely to have toxoplasma . so is toxo manipulating our brains as an evolutionary strategy to get predatory cats to eat us ? or are our brains just similar enough to a rodent 's that the same neurological tricks that lure them in catch us in the net , too ? and is toxo the reason so many people love cats and keep them as pets ? well , the jury 's still out on that one . some recent studies even contradict the idea . regardless , toxoplasma has definitely benefited from humans to become one of the world 's most successful parasites . it 's not just our willingness to let cats on our dining room tables or in our beds . raising livestock and building cities which attract rodents has provided billions of new hosts , and you and your cat may be two of them .
|
some recent studies even contradict the idea . regardless , toxoplasma has definitely benefited from humans to become one of the world 's most successful parasites . it 's not just our willingness to let cats on our dining room tables or in our beds .
|
toxoplasma is one of the most common parasites in the world . how did it become so successful ?
|
translator : andrea mcdonough reviewer : bedirhan cinar fourth and nineteen , folks , they 've got ta have a play as time 's ticking away because they 've got to stay in this ball game , they 've got to win . they come out lined up in the empty set , three receivers to the right , two to the left . defense looks like they 're gon na to man up with no safety . this is the exact offensive match-up that they want : the best receiver lined up against the linebacker . quarterback steps back to receive the ball , five yards deep in the gun . he takes a snap , drops three steps , he plants his back foot , he 's looking for an opening . there 's a blitz coming off the edge ! he steps up to avoid the rush . he 's looking down field . he 's got the inside receiver making a cut . he 's got a step on the linebacker . quarterback has a beat on it . he lets the ball go , it 's in the air ! receiver is out in front of the defender . he 's got it beat ! he 's out in front , racing for the ball ! it 's coming down ! he cradles it at the fifteen ! he 's at the ten , five ! touchdown ! unbelievable play ! now , wait a minute . of course , it 's believable , it 's physics , specifically the differences between scalars and vectors . so , let 's just see that replay . `` quarterback steps back to receive the ball , five yards deep in the gun . '' stop . see , measurements are defined as two different quantities . scalars are measurements with only numbers , and vectors are measurements with direction . for example , when that quarterback takes the snap , he 's five yards away , but from where ? back from the line of scrimmage , so the five yards by itself is a scalar quantity . when you add a direction , like five yards deep , it becomes a vector quantity . five yards - scalar , five yards deep - vector . ok , go ahead . `` he takes a snap , drops three steps . he plants his back foot , he 's looking for an opening . there 's a blitz coming off the edge ! he steps up to avoid the rush . '' whoa ! here 's a difference between distance and displacement . distance is a measurement without identifying where you moved . it 's a scalar quantity . when the quarterback makes a three-step drop , he moves about three yards back . when he moves about another three yards forward , when he steps up into the pocket , so that quarterback moves a total distance of six yards . that 's a distance , that 's a scalar . now , displacement is a vector quantity , describing about how far out of place the object is . so the quarterback dropped back three yards and then moved back forward three yards , he 's in the exact same place where he started . so , his displacement is zero yards . distance - six yards , displacement - zero yards . so , let 's look at what happened next . `` quarterback has a beat on it , he let 's the ball go ! it 's in the air ! receiver is out in front of the defender . '' stop . so , here 's speed and velocity , but let 's just do one thing at a time . so , speed is measurement without direction , it 's a scalar quantity . velocity is a vector quantity . it is that object 's speed , but with a direction of motion . so the receiver accelerates away , gaining both speed and distance . this takes the receiver 5 seconds to run those 50 yards . so his average speed , in any given time , is 10 yards/second . the linebacker tries to keep up , but his overall speed is slower , he only goes 35 yards in those 5 seconds , so his average speed is only 7 yards/second . they 're both traveling in a forward direction , so their velocity is also positive . you ca n't go from resting to your peak speed immediately . you 've got to build up to it . this is acceleration . at first the linebacker can keep up with that receiver , but eventually the faster receiver pulls away . that 's acceleration , the change in speed over time . acceleration is a vector quantity . it describes a rate at which an object changes velocity . like velocity , acceleration is a vector . it happens in a direction . so let 's just look at that play just one more time . `` quarterback steps back to receive the ball , five yards deep in the gun . '' vector ! `` he takes a snap , drops three steps , he plants his back foot . he 's looking for an opening . there 's a blitz coming off the edge ! he steps up to avoid the rush . '' displacement ! `` he 's got the inside receiver making a cut . he 's got a step on the linebacker . the quarterback has a beat on it . he let 's the ball go ! it 's in the air ! receiver is out in front of the defender ! '' velocity ! `` he 's got it beat ! he 's out in front , racing for the ball ! it 's coming down ! he cradles it at the fifteen , he 's at the ten , five ! '' acceleration ! `` touchdown ! unbelievable play ! that was a great play as time expired , resulting in the touchdown and ultimately the win and pure effort . '' and pure science .
|
see , measurements are defined as two different quantities . scalars are measurements with only numbers , and vectors are measurements with direction . for example , when that quarterback takes the snap , he 's five yards away , but from where ?
|
scalars are measurements with only _________ . vectors are measurements with _________ .
|
the sight of mistletoe may either send you scurrying , or if you have your eye on someone , awaiting an opportunity beneath its snow white berries , but how did the festive christmas tradition of kissing under mistletoe come about ? the long-lived custom intertwines the mythology and biology of this intriguing plant . there are more than 1,000 species of mistletoe , which grows the world over . in fact , the ancient europeans were so captivated by the plant 's unusual growth habits that they included it in their legends and myths . in ancient rome , pliny the elder described how the druid priesthood in ancient england believed that mistletoe was a plant dropped down from heaven by the gods . that explained its unlikely position amongst the high branches of certain trees . they also believed it had powers of healing and bestowing fertility . meanwhile , scandinavian legend told of the plant 's mystical qualities in the story of the god baldr and his adoring mother frigg , goddess of love , marriage , and fertility . frigg loved her son so much that she commanded every plant , animal , and inanimate object to vow they 'd never harm him . in her fervor , however , she overlooked the mistletoe . the mischievous god loki realized this oversight and pierced baldr 's heart with an arrow carved from a mistletoe branch . frigg cried tears of such sadness that they formed the mistletoe 's pearly berries , making the other gods pity her and agree to resurrect baldr . hearing the news , frigg became so overjoyed that she transformed the mistletoe from a symbol of death into one of peace and love . she mandated a one-day truce for all fights , and that everyone embrace beneath its branches when they passed to spread more love into the world . in the 17th century , british colonists arriving in the new world found a different , but very similar looking , species of mistletoe . they applied it to these tales of magic , fertility , and love , spreading the mistletoe-hanging tradition from europe into america . by the 18th century , people in britain had turned this into a christmas tradition , but this custom comes down to more than just human imagination . all of it was inspired by the plant 's intriguing biology . we see mistletoe as a festive decoration , but draped on tree boughs in the wild , it 's known as a partly parasitic plant . mistletoe relies on modified roots called haustoria that penetrate the tree bark and siphon off the water and minerals trees carry up their trunks to colonize nearby trees with its seeds , mistletoe depends on birds and other creatures to do the dispersing . birds that eat the mistletoe 's sticky white berries sometimes get rid of the gluey seeds by wiping them off onto tree bark . or with a bit of luck , they excrete the indigestible seed onto a tree where it germinates and starts to grow . with its resilience and foliage that stays lush even while the surrounding trees lose their leaves , you can see why mistletoe captivated our superstitious ancestors . they saw these as signs of the plant 's magical qualities and fertility . even today , the mistletoe inspires wonder with the diversity of wildlife it supports . more than just a parasite , it 's also known as a keystone species . it 's eaten by a diversity of animals , including deer , elk , squirrels , chipmunks , porcupines , robins , bluebirds , morning doves , and the butterfly genus delias . some mistletoe species produce dense bushes , which are excellent nesting locations for a variety of birds . and despite their parasitic relationship with trees , mistletoes can also help other plants . for instance , juniper sprouts near mistletoe to benefit from the visiting berry-eating birds . through the many benefits it provides , mistletoe influences diversity , and allows ecosystems to flourish . you might even say that for this iconic plant , life imitates legend . in the wild , mistletoe has the power to bring things together , and in our own traditions , we see that happening , too .
|
frigg loved her son so much that she commanded every plant , animal , and inanimate object to vow they 'd never harm him . in her fervor , however , she overlooked the mistletoe . the mischievous god loki realized this oversight and pierced baldr 's heart with an arrow carved from a mistletoe branch .
|
the term parasite has a negative connotation . do you think that connotation applies to mistletoe , and can you think of other examples where prejudice arises from poorly understood situations ?
|
`` hi , bob . '' `` morning , kelly . the tulips looks great . '' have you ever wondered how your dog experiences the world ? here 's what she sees . not terribly interesting . but what she smells , that 's a totally different story . and it begins at her wonderfully developed nose . as your dog catches the first hints of fresh air , her nose 's moist , spongy outside helps capture any scents the breeze carries . the ability to smell separately with each nostril , smelling in stereo , helps to determine the direction of the smell 's source so that within the first few moments of sniffing , the dog starts to become aware of not just what kind of things are out there but also where they 're located . as air enters the nose , a small fold of tissue divides it into two separate folds , one for breathing and one just for smelling . this second airflow enters a region filled with highly specialized olfactory receptor cells , several hundred millions of them , compaired to our five million . and unlike our clumsy way of breathing in and out through the same passage , dogs exhale through slits at the side of their nose , creating swirls of air that help draw in new odor molecules and allow odor concentration to build up over mulitple sniffs . but all that impressive nasal architecture would n't be much help without something to process the loads of information the nose scoops up . and it turns out that the olfactory system dedicated to proessing smells takes up many times more relative brain area in dogs than in humans . all of this allows dogs to distinguish and remember a staggering variety of specific scents at concentrations up to 100 million times less than what our noses can detect . if you can smell a spritz of perfume in a small room , a dog would have no trouble smelling it in an enclosed stadium and distinguishing its ingredients , to boot . and everything in the street , every passing person or car , any contents of the neighbor 's trash , each type of tree , and all the birds and insects in it has a distinct odor profile telling your dog what it is , where it is , and which direction it 's moving in . besides being much more powerful than ours , a dog 's sense of smell can pick up things that ca n't even be seen at all . a whole separate olfactory system , called the vomeronasal organ , above the roof of the mouth , detects the hormones all animals , including humans , naturally release . it lets dogs identify potential mates , or distinguish between friendly and hostile animals . it alerts them to our various emotional states , and it can even tell them when someone is pregnant or sick . because olfaction is more primal than other senses , bypassing the thalamus to connect directly to the brain structures involving emotion and instinct , we might even say a dog 's perception is more immediate and visceral than ours . but the most amazing thing about your dog 's nose is that it can traverse time . the past appears in tracks left by passersby , and by the warmth of a recently parked car where the residue of where you 've been and what you 've done recently . landmarks like fire hydrants and trees are aromatic bulletin boards carrying messages of who 's been by , what they 've been eating , and how they 're feeling . and the future is in the breeze , alerting them to something or someone approaching long before you see them . where we see and hear something at a single moment , a dog smells an entire story from start to finish . in some of the best examples of canine-human collaboration , dogs help us by sharing and reacting to those stories . they can respond with kindness to people in distress , or with aggression to threats because stress and anger manifest as a cloud of hormones recognizable to the dog 's nose . with the proper training , they can even alert us to invisible threats ranging from bombs to cancer . as it turns out , humanity 's best friend is not one who experiences the same things we do , but one whose incredible nose reveals a whole other world beyond our eyes .
|
because olfaction is more primal than other senses , bypassing the thalamus to connect directly to the brain structures involving emotion and instinct , we might even say a dog 's perception is more immediate and visceral than ours . but the most amazing thing about your dog 's nose is that it can traverse time . the past appears in tracks left by passersby , and by the warmth of a recently parked car where the residue of where you 've been and what you 've done recently .
|
explain this statement : a dog 's nose can traverse time .
|
translator : andrea mcdonough reviewer : bedirhan cinar what does `` going viral '' on the internet really mean , and why does it happen so quickly ? why is a financial institution too big to fail ? how does a virus in africa end up in the united states in a matter of hours ? why are facebook and google such powerful companies at creating global connections ? well , in a word : networks . but what are networks ? everyone knows about their social network , but there are all different kinds of networks you probably have n't thought about . networks are collections of links which combine by specific rules and behaviors if they are alive . we say that networks are alive because they are in constant change . over time , the connections within a network migrate and concentrate in new places , forming evolving structures . how the evolution and concentration of constantly changing connections occurs is the subject of a whole discipline called network theory . we can think of networks as neighborhoods . neighborhoods are defined by maps . a google map demonstrates the relationship between locations in exactly the same fashion a network connects hubs and nodes , using streets as links to connect neighborhoods . the reason a network can expand and evolve so quickly is based upon a mathematical concept called power functions . a power function is a mathematical amplification mechanism , which over specific and very small ranges , accelerates changes logarithmically . that is , a very small change in one parameter produces a huge change in another over a very specific range of values . an example of how network structure emerges is the algorithm used by google . as the number of links around a search term , say `` friends '' , increases , connections begin to form among millions of different searches using the term `` friend '' . what google has cleverly accomplished is a real-time mathematical model for how to predict the emergence of growing connections among billions of search terms . the algorithm google derived collects the number of references to any search object . as references to a search object increase , the number of links also increases , creating a node . as the node increases in size , it eventually becomes a hub , which links to many nodes . networks will continue to emerge as new ways of connecting and creating neighborhoods are defined . perhaps you can begin to see why networks are so powerful . as google continues to collect the billions of daily searches , new clusters of links will rapidly emerge , forming additional and growing networks . despite the logarithmic expansion of your network , the laws of six degrees of separation still apply . therefore , if you explore a close friend or acquaintances in you facebook network , everyone on average will be separated by six individuals or less and a map of your social network will create neighborhoods linked by common connections among friends .
|
networks will continue to emerge as new ways of connecting and creating neighborhoods are defined . perhaps you can begin to see why networks are so powerful . as google continues to collect the billions of daily searches , new clusters of links will rapidly emerge , forming additional and growing networks .
|
why are networks so powerful ?
|
for as far back as we can trace our existence , humans have been fascinated with death and resurrection . nearly every religion in the world has some interpretation of them , and from our earliest myths to the latest cinematic blockbusters , the dead keep coming back . but is resurrection really possible ? and what is the actual difference between a living creature and a dead body , anyway ? to understand what death is , we need to understand what life is . one ancient theory was an idea called vitalism , which claimed that living things were unique because they were filled with a special substance , or energy , that was the essence of life . whether it was called qi , lifeblood , or humors , the belief in such an essence was common throughout the world , and still persists in the stories of creatures who can somehow drain life from others , or some form of magical sources that can replenish it . vitalism began to fade in the western world following the scientific revolution in the 17th century . rené descartes advanced the notion that the human body was essentially no different from any other machine , brought to life by a divinely created soul located in the brain 's pineal gland . and in 1907 , dr. duncan mcdougall even claimed that the soul had mass , weighing patients immediately before and after death in an attempt to prove it . though his experiments were discredited , much like the rest of vitalism , traces of his theory still come up in popular culture . but where do all these discredited theories leave us ? what we now know is that life is not contained in some magical substance or spark , but within the ongoing biological processes themselves . and to understand these processes , we need to zoom down to the level of our individual cells . inside each of these cells , chemical reactions are constantly occurring , powered by the glucose and oxygen that our bodies convert into the energy-carrying molecule known as atp . cells use this energy for everything from repair to growth to reproduction . not only does it take a lot of energy to make the necessary molecules , but it takes even more to get them where they need to be . the universal phenomenon of entropy means that molecules will tend towards diffusing randomly , moving from areas of high concentration to low concentration , or even breaking apart into smaller molecules and atoms . so cells must constantly keep entropy in check by using energy to maintain their molecules in the very complicated formations necessary for biological functions to occur . the breaking down of these arrangements when the entire cell succumbs to entropy is what eventually results in death . this is the reason organisms ca n't be simply sparked back to life once they 've already died . we can pump air into someone 's lungs , but it wo n't do much good if the many other processes involved in the respiratory cycle are no longer functioning . similarly , the electric shock from a defibrillator does n't jump-start an inanimate heart , but resynchronizes the muscle cells in an abnormally beating heart so they regain their normal rhythm . this can prevent a person from dying , but it wo n't raise a dead body , or a monster sewn together from dead bodies . so it would seem that all our various medical miracles can delay or prevent death but not reverse it . but that 's not as simple as it sounds because constant advancements in technology and medicine have resulted in diagnoses such as coma , describing potentially reversible conditions , under which people would have previously been considered dead . in the future , the point of no return may be pushed even further . some animals are known to extend their lifespans or survive extreme conditions by slowing down their biological processes to the point where they are virtually paused . and research into cryonics hopes to achieve the same by freezing dying people and reviving them later when newer technology is able to help them . see , if the cells are frozen , there 's very little molecular movement , and diffusion practically stops . even if all of a person 's cellular processes had already broken down , this could still conceivably be reversed by a swarm of nanobots , moving all the molecules back to their proper positions , and injecting all of the cells with atp at the same time , presumably causing the body to simply pick up where it left off . so if we think of life not as some magical spark , but a state of incredibly complex , self-perpetuating organization , death is just the process of increasing entropy that destroys this fragile balance . and the point at which someone is completely dead turns out not to be a fixed constant , but simply a matter of how much of this entropy we 're currently capable of reversing .
|
not only does it take a lot of energy to make the necessary molecules , but it takes even more to get them where they need to be . the universal phenomenon of entropy means that molecules will tend towards diffusing randomly , moving from areas of high concentration to low concentration , or even breaking apart into smaller molecules and atoms . so cells must constantly keep entropy in check by using energy to maintain their molecules in the very complicated formations necessary for biological functions to occur .
|
atoms and molecules diffuse _____ .
|
the largest organ in your body is n't your liver or your brain . it 's your skin , with a surface area of about 20 square feet in adults . though different areas of the skin have different characteristics , much of this surface performs similar functions , such as sweating , feeling heat and cold , and growing hair . but after a deep cut or wound , the newly healed skin will look different from the surrounding area , and may not fully regain all its abilities for a while , or at all . to understand why this happens , we need to look at the structure of the human skin . the top layer , called the epidermis , consists mostly of hardened cells , called keratinocytes , and provides protection . since its outer layer is constantly being shed and renewed , it 's pretty easy to repair . but sometimes a wound penetrates into the dermis , which contains blood vessels and the various glands and nerve endings that enable the skin 's many functions . and when that happens , it triggers the four overlapping stages of the regenerative process . the first stage , hemostasis , is the skin 's response to two immediate threats : that you 're now losing blood and that the physical barrier of the epidermis has been compromised . as the blood vessels tighten to minimize the bleeding , in a process known as vasoconstriction , both threats are averted by forming a blood clot . a special protein known as fibrin forms cross-links on the top of the skin , preventing blood from flowing out and bacteria or pathogens from getting in . after about three hours of this , the skin begins to turn red , signaling the next stage , inflammation . with bleeding under control and the barrier secured , the body sends special cells to fight any pathogens that may have gotten through . among the most important of these are white blood cells , known as macrophages , which devour bacteria and damage tissue through a process known as phagocytosis , in addition to producing growth factors to spur healing . and because these tiny soldiers need to travel through the blood to get to the wound site , the previously constricted blood vessels now expand in a process called vasodilation . about two to three days after the wound , the proliferative stage occurs , when fibroblast cells begin to enter the wound . in the process of collagen deposition , they produce a fibrous protein called collagen in the wound site , forming connective skin tissue to replace the fibrin from before . as epidermal cells divide to reform the outer layer of skin , the dermis contracts to close the wound . finally , in the fourth stage of remodeling , the wound matures as the newly deposited collagen is rearranged and converted into specific types . through this process , which can take over a year , the tensile strength of the new skin is improved , and blood vessels and other connections are strengthened . with time , the new tissue can reach from 50-80 % of some of its original healthy function , depending on the severity of the initial wound and on the function itself . but because the skin does not fully recover , scarring continues to be a major clinical issue for doctors around the world . and even though researchers have made significant strides in understanding the healing process , many fundamental mysteries remain unresolved . for instance , do fibroblast cells arrive from the blood vessels or from skin tissue adjacent to the wound ? and why do some other mammals , such as deer , heal their wounds much more efficiently and completely than humans ? by finding the answers to these questions and others , we may one day be able to heal ourselves so well that scars will be just a memory .
|
with bleeding under control and the barrier secured , the body sends special cells to fight any pathogens that may have gotten through . among the most important of these are white blood cells , known as macrophages , which devour bacteria and damage tissue through a process known as phagocytosis , in addition to producing growth factors to spur healing . and because these tiny soldiers need to travel through the blood to get to the wound site , the previously constricted blood vessels now expand in a process called vasodilation . about two to three days after the wound , the proliferative stage occurs , when fibroblast cells begin to enter the wound .
|
the process of previously constricted blood vessels expanding is known as :
|
unfortunately , i know very little about dubnium , i am not sure anybody knows much about it , but it is named after the russian atomic research establishment , dubna . in these artificial elements , the elements are either named after somebody who is famous like rutherford for rutherfordium or in the place where an element was first discovered , but often where there is argument about who discovered the element first , then it is more equitable to name it after scientists .
|
unfortunately , i know very little about dubnium , i am not sure anybody knows much about it , but it is named after the russian atomic research establishment , dubna . in these artificial elements , the elements are either named after somebody who is famous like rutherford for rutherfordium or in the place where an element was first discovered , but often where there is argument about who discovered the element first , then it is more equitable to name it after scientists .
|
where does the name dubnium come from ?
|
statistics are persuasive . so much so that people , organizations , and whole countries base some of their most important decisions on organized data . but there 's a problem with that . any set of statistics might have something lurking inside it , something that can turn the results completely upside down . for example , imagine you need to choose between two hospitals for an elderly relative 's surgery . out of each hospital 's last 1000 patient 's , 900 survived at hospital a , while only 800 survived at hospital b . so it looks like hospital a is the better choice . but before you make your decision , remember that not all patients arrive at the hospital with the same level of health . and if we divide each hospital 's last 1000 patients into those who arrived in good health and those who arrived in poor health , the picture starts to look very different . hospital a had only 100 patients who arrived in poor health , of which 30 survived . but hospital b had 400 , and they were able to save 210 . so hospital b is the better choice for patients who arrive at hospital in poor health , with a survival rate of 52.5 % . and what if your relative 's health is good when she arrives at the hospital ? strangely enough , hospital b is still the better choice , with a survival rate of over 98 % . so how can hospital a have a better overall survival rate if hospital b has better survival rates for patients in each of the two groups ? what we 've stumbled upon is a case of simpson 's paradox , where the same set of data can appear to show opposite trends depending on how it 's grouped . this often occurs when aggregated data hides a conditional variable , sometimes known as a lurking variable , which is a hidden additional factor that significantly influences results . here , the hidden factor is the relative proportion of patients who arrive in good or poor health . simpson 's paradox is n't just a hypothetical scenario . it pops up from time to time in the real world , sometimes in important contexts . one study in the uk appeared to show that smokers had a higher survival rate than nonsmokers over a twenty-year time period . that is , until dividing the participants by age group showed that the nonsmokers were significantly older on average , and thus , more likely to die during the trial period , precisely because they were living longer in general . here , the age groups are the lurking variable , and are vital to correctly interpret the data . in another example , an analysis of florida 's death penalty cases seemed to reveal no racial disparity in sentencing between black and white defendants convicted of murder . but dividing the cases by the race of the victim told a different story . in either situation , black defendants were more likely to be sentenced to death . the slightly higher overall sentencing rate for white defendants was due to the fact that cases with white victims were more likely to elicit a death sentence than cases where the victim was black , and most murders occurred between people of the same race . so how do we avoid falling for the paradox ? unfortunately , there 's no one-size-fits-all answer . data can be grouped and divided in any number of ways , and overall numbers may sometimes give a more accurate picture than data divided into misleading or arbitrary categories . all we can do is carefully study the actual situations the statistics describe and consider whether lurking variables may be present . otherwise , we leave ourselves vulnerable to those who would use data to manipulate others and promote their own agendas .
|
statistics are persuasive . so much so that people , organizations , and whole countries base some of their most important decisions on organized data .
|
what type of variable should we be aware of when interpreting statistics ?
|
there is an environmental mystery afoot , and it begins with a seemingly trivial detail that reveals a disaster of global proportions . one day , you notice that the honey you slather on your morning toast is more expensive . instead of switching to jam , you investigate the reason for the price hike . what you find is shocking . the number of domesticated honeybees in the us has been decreasing at an alarming rate . this decline appears too big to be explained by the usual causes of bee death alone : disease , parasites or starvation . a typical crime scene has almost no adult bees left in the hive , except , perhaps , a lonely queen and a few other survivors . it 's full of untouched food stores and a brood of unborn larvae , suggesting that the adults vacated without waiting for them to hatch . but what 's particularly eerie is that there 's no tell-tale mass of dead or dying bees nearby . either they have forgotten their way back to the hive , or they have simply disappeared . these mysterious disappearances are n't new . humans have been collecting honey for centuries . but it was n't until european settlers in the 1600 's introduced the subspecies , apis mellifera , that we domesticated bees . since the 19th century , beekeepers have reported occasional mass disappearances , giving them enigmatic names like disappearing disease , spring dwindle disease and autumn collapse . but when in 2006 such losses were found to affect more than half of all hives in the us , the phenomenon got a new name : colony collapse disorder . the most frightening thing about this mystery is n't that we 'll have to go back to using regular sugar in our tea . we farm bees for their honey , but they also pollinate our crops on an industrial scale , generating over 1/3 of america 's food production this way . so , how can we find the culprit behind this calamity ? here are three of the possible offenders . exhibit a : pests and disease . most infamous is the varroa mite , a minuscule red pest that not only invades colonies and feeds on bees , but also transfers pathogens that stunt bee growth and shortens their life span . exhibit b : genetics . the queen is the core of a healthy hive . but nowadays , the millions of queen bees distributed in commercial hives are bred from just a few original queens , which raises the worry about a lack of genetic diversity which could weaken bees ' defenses against pathogens and pests . exhibit c : chemicals . pesticides used both on commercial beehives and agricultural crops to ward off parasites could be getting into the food and water that honeybees consume . researchers have even found that some pesticides damage the honeybees ' homing abilities . so we have a file full of clues but no clear leads . in reality , scientists , the actual detectives on this case , face disagreement over what causes colony collapse disorder . for now , we assume that several factors are the cause . honeybees are n't necessarily in danger of extinction , but fewer bees overall means less pollination and higher food costs , so it 's crucial that scientists solve the case of the vanishing bees . because while having less honey might be a buzzkill , crop shortages are something that would truly sting .
|
the queen is the core of a healthy hive . but nowadays , the millions of queen bees distributed in commercial hives are bred from just a few original queens , which raises the worry about a lack of genetic diversity which could weaken bees ' defenses against pathogens and pests . exhibit c : chemicals .
|
what could be the value of wild bees in this scenario ?
|
mysteries of vernacular : lady , woman . lady is tied to a number of words that seem at first glance etymologically unrelated . she traces her roots back to the old english words hlaf , which referred to a loaf of bread and is the direct ancestor of our modern word loaf , and daege , which meant maid and is the root of our word dairy , the place where the dairymaid works . together , hlaf and daege became hlafdige , literally loaf maid , or , more figuratively , kneader of bread . as early as the ninth century , hlafdige was the name for a mistress of servants , or the female head of the household . the old english word for a male head of household was hlafweard , a compound of hlaf , loaf , and weard , which meant keeper and is the word of modern words like ward and warden . both hlafweard , the breadwinner , and hlafdige , the bread kneader , came to be titles of respect , referring to citizens of higher social standing . through a process known as syncopation , both words lost their internal sounds to become lord and lady , respectively . though still an expression of courtesy , lady has since moved down the ladder of social standing and is now often used to mean simply a woman .
|
both hlafweard , the breadwinner , and hlafdige , the bread kneader , came to be titles of respect , referring to citizens of higher social standing . through a process known as syncopation , both words lost their internal sounds to become lord and lady , respectively . though still an expression of courtesy , lady has since moved down the ladder of social standing and is now often used to mean simply a woman .
|
how is the syncopation of words similar to the syncopation of music ?
|
in 1985 , 16-year-old douglas casa , ran the championship 10,000 meter track race at the empire state games . suddenly , with just 200 meters to go , he collapsed , got back up and then collapsed again on the final straightaway , with his body temperature at dangerous levels . he had suffered an exertional heat stroke . fortunately , with immediate and proper treatment , he survived the potentially fatal episode and has since helped save 167 people in similar circumstances . from ancient soldiers on the battlefield to modern day warriors on the gridiron , exertional heat stroke , or sunstroke , has long been a serious concern . and unlike classical heat stroke , which affects vulnerable people such as infants and the elderly during heat waves , exertional heat stroke is caused by intense exercise in the heat , and is one of the top three killers of athletes and soldiers in training . when you exercise , nearly 80 % of the energy you use is transformed into heat . in normal circumstances , this is what 's known as compensable heat stress . and your body can dissipate the heat as quickly as it 's generated through cooling methods like the evaporation of sweat . but with uncompensable heat stress , your body is unable to lose enough heat due to overexertion or high temperatures in humidity , which raises your core temperature beyond normal levels . this causes the proteins and cell membranes to denature , creating cells that no longer function properly and begin to leak their contents . if these leaky cells proliferate through the body , the results can be devastating . including liver damage , blood clot formation in the kidneys , damage to the gastrointestinal tract and even the failure of vital organs . so how do you diagnose an exertional heat stroke ? the main criterion is a core body temperature greater than 40 degrees celsius observed along with physical symptoms such as increased heart rate , low blood pressure and rapid breathing or signs of central nervous system disfunction such as confused behavior , aggression or loss of consciousness . the most feasible and accurate way to assess core body temperature is with a rectal thermometer as other common temperature-taking methods are not accurate in these circumstances . as far as treatment goes , the most important thing to remember is cool first , transport second . because the human body can withstand a core temperature above 40 degrees celsius for about 30 minutes before cell damage sets in , it 's essential to initiate rapid cooling on site in order to lower it as quickly as possible . after any athletic or protective gear has been removed from the victim , place them in an ice water tub while stirring the water and monitoring vitals continuously . if this is not possible , dousing in ice water and applying wet towels over the entire body can help . but before you start anything , emergency services should be called . as you wait , it 's important to keep the victim calm while cooling as much surface area as possible until emergency personnel arrive . if medical staff are available on site , cooling should continue until a core temperature of 38.9 degrees celsius is reached . the sun is known for giving life , but it can also take life away if we 're not careful , even affecting the strongest among us . as dr. jj levick wrote of exertional heat stroke in 1859 , `` it strikes down its victim with his full armor on . youth , health and strength oppose no obstacle to its power . '' but although this condition is one of the top three leading causes of death in sports , it has been 100 % survivable with proper care .
|
suddenly , with just 200 meters to go , he collapsed , got back up and then collapsed again on the final straightaway , with his body temperature at dangerous levels . he had suffered an exertional heat stroke . fortunately , with immediate and proper treatment , he survived the potentially fatal episode and has since helped save 167 people in similar circumstances .
|
what is the temperature that is considered the criterion for exertional heat stroke ?
|
you probably know that all stuff is made up of atoms and that an atom is a really , really , really , really tiny particle . every atom has a core , which is made up of at least one positively charged particle called a proton , and in most cases , some number of neutral particles called neutrons . that core is surrounded by negatively charged particles called electrons . the identity of an atom is determined only by the number of protons in its nucleus . hydrogen is hydrogen because it has just one proton , carbon is carbon because it has six , gold is gold because it has 79 , and so on . indulge me in a momentary tangent . how do we know about atomic structure ? we ca n't see protons , neutrons , or electrons . so , we do a bunch of experiments and develop a model for what we think is there . then we do some more experiments and see if they agree with the model . if they do , great . if they do n't , it might be time for a new model . we 've had lots of very different models for atoms since democritus in 400 bc , and there will almost certainly be many more to come . okay , tangent over . the cores of atoms tend to stick together , but electrons are free to move , and this is why chemists love electrons . if we could marry them , we probably would . but electrons are weird . they appear to behave either as particles , like little baseballs , or as waves , like water waves , depending on the experiment that we perform . one of the weirdest things about electrons is that we ca n't exactly say where they are . it 's not that we do n't have the equipment , it 's that this uncertainty is part of our model of the electron . so , we ca n't pinpoint them , fine . but we can say there 's a certain probability of finding an electron in a given space around the nucleus . and that means that we can ask the following question : if we drew a shape around the nucleus such that we would be 95 % sure of finding a given electron within that shape , what would it look like ? here are a few of these shapes . chemists call them orbitals , and what each one looks like depends on , among other things , how much energy it has . the more energy an orbital has , the farther most of its density is from the nucleus . by they way , why did we pick 95 % and not 100 % ? well , that 's another quirk of our model of the electron . past a certain distance from the nucleus , the probability of finding an electron starts to decrease more or less exponentially , which means that while it will approach zero , it 'll never actually hit zero . so , in every atom , there is some small , but non-zero , probability that for a very , very short period of time , one of its electrons is at the other end of the known universe . but mostly electrons stay close to their nucleus as clouds of negative charged density that shift and move with time . how electrons from one atom interact with electrons from another determines almost everything . atoms can give up their electrons , surrendering them to other atoms , or they can share electrons . and the dynamics of this social network are what make chemistry interesting . from plain old rocks to the beautiful complexity of life , the nature of everything we see , hear , smell , taste , touch , and even feel is determined at the atomic level .
|
if we could marry them , we probably would . but electrons are weird . they appear to behave either as particles , like little baseballs , or as waves , like water waves , depending on the experiment that we perform . one of the weirdest things about electrons is that we ca n't exactly say where they are .
|
electrons behave as particles or waves depending on ________ .
|
magnesium is one of the lightest elements . it ’ s right at the beginning of the period table and , in fact , it ’ s the first of the light metals that you can actually use . lithium and sodium react violently with water so you can ’ t really use them as a metal and beryllium is fantastically poisonous so unless you are using it in the lab where you can be sure that nobody is going to touch it , it ’ s useless , so magnesium is the lightest metal you can use . so , for example , if you are trying to make mobile phones that are really light , then you can make the frame of the mobile phone out of magnesium . you can use it for laptops . there is a professor in germany , who has promised to send me a laptop frame made of magnesium , but it hasn ’ t arrived yet . so another classroom classic . normally comes along in chemistry lesson number three i guess , time to combust a reactive metal in the air , so the reactive metal we are going to look at is magnesium . the other thing that is good about magnesium is that there is a lot of magnesium about in the world , so it is not an element that is difficult to get . if you look at this periodic table here , which is from barcelona so it is in catalan , the areas of these , each element are approximately the abundance in the world . some of the rarer elements have a slightly bigger squares than they should do so you can read the letters , but you see magnesium here is pretty large , so magnesium and sodium are pretty common , beryllium is much less common , and lithium is even less common than that , so there is lots of magnesium . magnesium is very light , it is very reactive , very pliable metal , it is very nice , it is easily alloyed with things like aluminium and other light metals to make very strong , very robust materials . used in construction , it ’ s used in high-performance components of cars . when i was a child when we got , had indigestion , we were given ‘ milk of magnesia ’ . magnesium oxide in water which came in these really nice blue bottles , sort of white looking liquid , didn ’ t taste very nice , but it was meant to be good for you , i am not sure if it was . it is used in the hulls of ships , you know like , warships , things like that , so incredibly strong , incredibly light but incredibly reactive if you give it enough energy . so we are going to combust it in the oxygen and see what happens . magnesium as you know , burns , and one of the ways that magnesium used to be used was for photographic flashlights , and you use bulbs like these which contain magnesium , inside a bulb filled with oxygen . and for each photograph you had to put this on the top of the camera . so i ’ ve got one here that i have taken out . so , if you look at it , so much heat has been produced by this tiny amount of magnesium , that it has melted the glass . so , let ’ s see what happens when we light it . you can see , really fierce bright white light that classical glow , everyone has seen this in the chemistry lab at school , fantastic reaction . it is one of the few metals which is meant to burn in nitrogen . in theory you can take a piece of magnesium , set fire to it in air so its burning well and then plunge it into nitrogen gas , and it should continue burning . i have tried this experiment lots of times and it ’ s never worked . in fact for 25 years i demonstrated this experiment to my lecture class when i was talking about nitrogen , and every time , it didn ’ t work , and the students thought , the poor professor , he has been made a fool of , it hasn ’ t worked and they didn ’ t know that it never worked and i would have been more surprised if it had done , but it taught them a bit about the chemistry of nitrogen and magnesium . why did you keep doing it if it never worked ? because it is a really good experiment , because it got such a good reaction from the audience . because it went wrong ? yes ! you were playing the fool on purpose ? yes ! so this is magnesium metal , but the magnesium metal here is not the ribbon which we normally see in perhaps , scientific labs or perhaps in school labs , this is a very , very fine powder of magnesium , so what we are going to do in a moment is bring on a really very powerful torch , a gas flame and we are going to see what happens when we sprinkle a little of this material into the flame . magnesium is also very important in all our lives , because magnesium is found in the green pigments in the leaves of all plants , in chlorophyll . chlorophyll is an organic molecule , carbon , hydrogen and nitrogen and in the middle there is an atom of magnesium , and it is chlorophyll which catches the sunlight and transfers it eventually to cause the reaction of carbon dioxide and water to make all the sugars and other things in the plant . if that didn ’ t happen none of us would be alive , because we all rely either directly or indirectly on plants , to give us the energy to live . i don ’ t understand completely the mechanism of photosynthesis , because the energy that is absorbed by one molecule , is transferred to another and another one as it were along a chain , but the magnesium is very important , if you don ’ t have magnesium there it is not nearly as efficient . let ’ s light it again .
|
so this is magnesium metal , but the magnesium metal here is not the ribbon which we normally see in perhaps , scientific labs or perhaps in school labs , this is a very , very fine powder of magnesium , so what we are going to do in a moment is bring on a really very powerful torch , a gas flame and we are going to see what happens when we sprinkle a little of this material into the flame . magnesium is also very important in all our lives , because magnesium is found in the green pigments in the leaves of all plants , in chlorophyll . chlorophyll is an organic molecule , carbon , hydrogen and nitrogen and in the middle there is an atom of magnesium , and it is chlorophyll which catches the sunlight and transfers it eventually to cause the reaction of carbon dioxide and water to make all the sugars and other things in the plant . if that didn ’ t happen none of us would be alive , because we all rely either directly or indirectly on plants , to give us the energy to live .
|
what is the name of the organic molecule that gives the green color to plants , and which has one magnesium atom in the middle of a structure composed of carbon , hydrogen and nitrogen atoms ?
|
this may look like a neatly arranged stack of numbers , but it 's actually a mathematical treasure trove . indian mathematicians called it the staircase of mount meru . in iran , it 's the khayyam triangle . and in china , it 's yang hui 's triangle . to much of the western world , it 's known as pascal 's triangle after french mathematician blaise pascal , which seems a bit unfair since he was clearly late to the party , but he still had a lot to contribute . so what is it about this that has so intrigued mathematicians the world over ? in short , it 's full of patterns and secrets . first and foremost , there 's the pattern that generates it . start with one and imagine invisible zeros on either side of it . add them together in pairs , and you 'll generate the next row . now , do that again and again . keep going and you 'll wind up with something like this , though really pascal 's triangle goes on infinitely . now , each row corresponds to what 's called the coefficients of a binomial expansion of the form ( x+y ) ^n , where n is the number of the row , and we start counting from zero . so if you make n=2 and expand it , you get ( x^2 ) + 2xy + ( y^2 ) . the coefficients , or numbers in front of the variables , are the same as the numbers in that row of pascal 's triangle . you 'll see the same thing with n=3 , which expands to this . so the triangle is a quick and easy way to look up all of these coefficients . but there 's much more . for example , add up the numbers in each row , and you 'll get successive powers of two . or in a given row , treat each number as part of a decimal expansion . in other words , row two is ( 1x1 ) + ( 2x10 ) + ( 1x100 ) . you get 121 , which is 11^2 . and take a look at what happens when you do the same thing to row six . it adds up to 1,771,561 , which is 11^6 , and so on . there are also geometric applications . look at the diagonals . the first two are n't very interesting : all ones , and then the positive integers , also known as natural numbers . but the numbers in the next diagonal are called the triangular numbers because if you take that many dots , you can stack them into equilateral triangles . the next diagonal has the tetrahedral numbers because similarly , you can stack that many spheres into tetrahedra . or how about this : shade in all of the odd numbers . it does n't look like much when the triangle 's small , but if you add thousands of rows , you get a fractal known as sierpinski 's triangle . this triangle is n't just a mathematical work of art . it 's also quite useful , especially when it comes to probability and calculations in the domain of combinatorics . say you want to have five children , and would like to know the probability of having your dream family of three girls and two boys . in the binomial expansion , that corresponds to girl plus boy to the fifth power . so we look at the row five , where the first number corresponds to five girls , and the last corresponds to five boys . the third number is what we 're looking for . ten out of the sum of all the possibilities in the row . so 10/32 , or 31.25 % . or , if you 're randomly picking a five-player basketball team out of a group of twelve friends , how many possible groups of five are there ? in combinatoric terms , this problem would be phrased as twelve choose five , and could be calculated with this formula , or you could just look at the sixth element of row twelve on the triangle and get your answer . the patterns in pascal 's triangle are a testament to the elegantly interwoven fabric of mathematics . and it 's still revealing fresh secrets to this day . for example , mathematicians recently discovered a way to expand it to these kinds of polynomials . what might we find next ? well , that 's up to you .
|
keep going and you 'll wind up with something like this , though really pascal 's triangle goes on infinitely . now , each row corresponds to what 's called the coefficients of a binomial expansion of the form ( x+y ) ^n , where n is the number of the row , and we start counting from zero . so if you make n=2 and expand it , you get ( x^2 ) + 2xy + ( y^2 ) . the coefficients , or numbers in front of the variables , are the same as the numbers in that row of pascal 's triangle .
|
the sum of elements in the row n=2 is the square of _____ .
|
the thermite reaction which is the reaction of aluminium and iron oxide is used to make iron and because aluminium has much stronger bonds to oxygen than iron that the reaction produces an enormous amount of heat and you can use this for welding pieces of metals together . so this is a thermite mixture , it is a mixture of iron oxide and aluminium powder and we are going to do some redox chemistry and we are going to generate some molten iron which will hopefully stream from the bottom of the flower pot . so here you can see the black particles of the iron oxide and the silver particles are the aluminium powder . so we get some heat on this and we start an instantaneous redox reaction so the aluminium and the iron oxide swap oxygens so the aluminium will become oxidised and the iron will become reduced hopefully we will generate a lot of molten iron which should come from the bottom of the test tube … of the flower pot . alright ! right . now there is a story about students in berkley that some students , or group of students , decided to do a practical joke on a tram of the sort that has one door where you go in and another when you go out . so a big group of students queued onto the tram and got into the front and there were enough of them so they could actually come out at the end at the other door and form a loop so they were just going round and round and round so the tram could not leave because they were just more and more people getting on . we ’ re going to run out of tape . and while they were doing this , other students went down under the tram and set off two thermite reactions and welded the metal wheels of the tram to the steel rails so that when the tram tried to leave , when the students eventually stopped going round and round , it was firmly welded to the tracks and could not move at all . it ’ s gone out . tell us about what is going on mate ! so instantly the thermite reaction starts and you can see that it ’ s so hot that it burnt a whole through the bottom of that terracotta flower pot . but if we go in close now brady , you can see all that really quite nice molten iron . now that is so hot that the iron itself has melted and it has formed this really quite big goo in the bottom on the sand . do you encourage these sorts of practical jokes ? no , no , no , no , no , our students are far more responsible . so as soon as the fire work , or the sparkler , hit the top of the thermite reaction , in the top of here , it started obviously , instantaneous redox reaction . so this is where the metals were fighting for the oxygen , the aluminium won that battle and the aluminium came out of this reaction as aluminium oxide . the iron was reduced and we can see that now in the bottom which is really hot so i am not going to get too close but you can see all of this really , really hot iron . the iron was molten , it dribbled out through the bottom of the flower pot and it is now cooling . it didn ’ t dribble out of the bottom of the flower pot . well it smashed its way out of the flower pot . well you can say that iron is in my blood , it is in your blood as well . it is iron that gives haemoglobin the red pigment in your blood , its red colour . so the reaction we saw was about 5 minutes ago and the iron that was generated is still glowing red hot and you can see it has fused itself to the bottom half of the flower pot , which it broke in its tumultuous step forward . it is an absolutely essential element to life , except for crabs which use copper but you will have to hear about that later . so iron is a really , really abundant metal which is used in lots and lots of structural material , so you get to see lots of pieces of iron around , some of the racking and even in fact some of these pieces of equipment have got high iron content . they have got other elements in them to form alloys like stainless steel . i have an extremely long standing interest in its chemistry and in particular , i made one compound of iron so called iron tetracarbonyl which had 4 groups round it and everybody had expected that it would have a shape like one of these . shaped with tetrahedron like that whereas , in fact , it had a much more irregular shape , the 4 groups were arranged like this , and so every since this , every time i hear the word iron i get quite excited . so this is iron wire , ok , and as you can it is a very small wire . it is 0.2 in diameter and you can see the shiny material underneath is iron that has not undergone oxidation so this is where it has been protected from the oxygen in the air now if we look at the iron at the top we can see that this looks really familiar especially because it looks like some of the rust which we can see at the bottom of some of our cars . so here is some iron oxide on top of the iron . the very first chemical experiment i did the chemical reaction was with iron and i think the same is true for many generations of school children . i heated up iron and sulphur together and made iron sulphide sort of blackish solid but then we put acid on it and got a terrible smell of bad eggs and this was my introduction to chemistry and i really loved it .
|
the thermite reaction which is the reaction of aluminium and iron oxide is used to make iron and because aluminium has much stronger bonds to oxygen than iron that the reaction produces an enormous amount of heat and you can use this for welding pieces of metals together . so this is a thermite mixture , it is a mixture of iron oxide and aluminium powder and we are going to do some redox chemistry and we are going to generate some molten iron which will hopefully stream from the bottom of the flower pot .
|
which compound did the professor encounter during his introduction to chemistry ? it was produced by the reaction between iron and sulfur and then , it was to used to react with hydrochloric acid , releasing smelly hydrogen sulfide .
|
among the great poets of literary history , certain names like homer , shakespeare , milton , and whitman are instantly recognizable . however , there 's an early 20th century great french poet whose name you may not know : guillaume apollinaire . he was a close friend and collaborator of artists like picasso , rousseau , and chagall . he coined the term surrealism , and he was even suspected of stealing the mona lisa in 1911 . during his short lifetime , he created poetry that combined text and image in a way that seemingly predicted an artistic revolution to come . in the late 19th and early 20th century paris , the low-rent districts of montmartre and montparnasse were home to every kind of starving artist . it was all they could afford . these painters , writers , and intellectuals , united in their artistic passion and counterculture beliefs , made up france 's bohemian subculture . and their works of art , literature , and intellect would shake up the world . at the turn of the 20th century , within this dynamic scene , art critic , poet , and champion of the avant-garde , guillaume apollinaire was a well-known fixture . as an art critic , apollinaire explained the cubist and surrealist movements to the world , and rose to the defense of many young artists in the face of what was often a xenophobic and narrow-minded public . as a poet , apollinaire was passionate about all forms of art and a connoisseur of medieval literature , especially calligraphy and illuminated initials . as a visionary , apollinaire saw a gap between two artistic institutions . on one side was the popular , highly lauded traditional art forms of the time . on the other , the forms of artistic expression made possible through surrealism , cubism , and new inventions , like the cinema and the phonograph . within that divide , through the creation of his most important contribution to poetry , the calligram , guillaume apollinaire built a bridge . apollinaire created the calligram as a poem picture , a written portrait , a thoughts drawing , and he used it to express his modernism and his desire to push poetry beyond the normal bounds of text and verse and into the 20th century . some of his calligrams are funny , like the `` lettre-océan . '' some of them are dedicated to his young dead friends , like `` la colombe poignardée et le jet d'eau . '' some of them are the expression of an emotional moment , as is `` il pleut '' : `` it 's raining women 's voices as if they had died even in memory , and it 's raining you as well , marvellous encounters of my life , o little drops . those rearing clouds begin to neigh a whole universe of auricular cities . listen if it rains while regret and disdain weep to an ancient music . listen to the bonds fall off which hold you above and below . '' each calligram is intended to allow readers to unchain themselves from the regular experience of poetry , and feel and see something new . `` lettre-océan '' is first an image to be seen before even the words are read . text-only elements combine with words in shapes and forms . two circular forms , one locked in a square , the other , morph beyond the page in the shape of a spiral . together they create a picture that hints towards cubism . then on closer reading of the text , the descriptive words within suggest the image of an aerial view of the eiffel tower . they give tribute to electromagnetic waves of the telegraph , a new form of communication at the time . undoubtedly , the deeply layered artistic expressions in apollinaire 's calligrams are not just a brilliant display of poetic prowess from a master of the form . each calligram itself is also a snapshot in time , encapsulating the passion , the excitement , and the anticipation of all the bohemian artists of paris , including apollinaire , most of whom are well ahead of their time , and with their innovative work , eagerly grasping for the future .
|
as a poet , apollinaire was passionate about all forms of art and a connoisseur of medieval literature , especially calligraphy and illuminated initials . as a visionary , apollinaire saw a gap between two artistic institutions . on one side was the popular , highly lauded traditional art forms of the time .
|
which new form of artistic liberty does apollinaire experiment with in his poetry ?
|
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 .
|
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 .
|
the first ten amendments were added to the constitution in :
|
so you 're stranded in a huge rainforest , and you 've eaten a poisonous mushroom . to save your life , you need the antidote excreted by a certain species of frog . unfortunately , only the female of the species produces the antidote , and to make matters worse , the male and female occur in equal numbers and look identical , with no way for you to tell them apart , except that the male has a distinctive croak . and it may just be your lucky day . to your left , you 've spotted a frog on a tree stump , but before you start running to it , you 're startled by the croak of a male frog coming from a clearing in the opposite direction . there , you see two frogs , but you ca n't tell which one made the sound . you feel yourself starting to lose consciousness , and realize you only have time to go in one direction before you collapse . what are your chances of survival if you head for the clearing and lick both of the frogs there ? what about if you go to the tree stump ? which way should you go ? press pause now to calculate odds yourself . 3 2 1 if you chose to go to the clearing , you 're right , but the hard part is correctly calculating your odds . there are two common incorrect ways of solving this problem . wrong answer number one : assuming there 's a roughly equal number of males and females , the probability of any one frog being either sex is one in two , which is 0.5 , or 50 % . and since all frogs are independent of each other , the chance of any one of them being female should still be 50 % each time you choose . this logic actually is correct for the tree stump , but not for the clearing . wrong answer two : first , you saw two frogs in the clearing . now you 've learned that at least one of them is male , but what are the chances that both are ? if the probability of each individual frog being male is 0.5 , then multiplying the two together will give you 0.25 , which is one in four , or 25 % . so , you have a 75 % chance of getting at least one female and receiving the antidote . so here 's the right answer . going for the clearing gives you a two in three chance of survival , or about 67 % . if you 're wondering how this could possibly be right , it 's because of something called conditional probability . let 's see how it unfolds . when we first see the two frogs , there are several possible combinations of male and female . if we write out the full list , we have what mathematicians call the sample space , and as we can see , out of the four possible combinations , only one has two males . so why was the answer of 75 % wrong ? because the croak gives us additional information . as soon as we know that one of the frogs is male , that tells us there ca n't be a pair of females , which means we can eliminate that possibility from the sample space , leaving us with three possible combinations . of them , one still has two males , giving us our two in three , or 67 % chance of getting a female . this is how conditional probability works . you start off with a large sample space that includes every possibility . but every additional piece of information allows you to eliminate possibilities , shrinking the sample space and increasing the probability of getting a particular combination . the point is that information affects probability . and conditional probability is n't just the stuff of abstract mathematical games . it pops up in the real world , as well . computers and other devices use conditional probability to detect likely errors in the strings of 1 's and 0 's that all our data consists of . and in many of our own life decisions , we use information gained from past experience and our surroundings to narrow down our choices to the best options so that maybe next time , we can avoid eating that poisonous mushroom in the first place .
|
let 's see how it unfolds . when we first see the two frogs , there are several possible combinations of male and female . if we write out the full list , we have what mathematicians call the sample space , and as we can see , out of the four possible combinations , only one has two males .
|
consider the same two frogs sitting next to each other again . we inform you that one of them is definitely male . what is the probability that the other is female ?
|
translator : tom carter reviewer : bedirhan cinar the periodic table is instantly recognizable . it 's not just in every chemistry lab worldwide , it 's found on t-shirts , coffee mugs , and shower curtains . but the periodic table is n't just another trendy icon . it 's a massive slab of human genius , up there with the taj mahal , the mona lisa , and the ice cream sandwich -- and the table 's creator , dmitri mendeleev , is a bonafide science hall-of-famer . but why ? what 's so great about him and his table ? is it because he made a comprehensive list of the known elements ? nah , you do n't earn a spot in science valhalla just for making a list . besides , mendeleev was far from the first person to do that . is it because mendeleev arranged elements with similar properties together ? not really , that had already been done too . so what was mendeleev 's genius ? let 's look at one of the first versions of the periodic table from around 1870 . here we see elements designated by their two-letter symbols arranged in a table . check out the entry of the third column , fifth row . there 's a dash there . from that unassuming placeholder springs the raw brilliance of mendeleev . that dash is science . by putting that dash there , dmitri was making a bold statement . he said -- and i 'm paraphrasing here -- y'all have n't discovered this element yet . in the meantime , i 'm going to give it a name . it 's one step away from aluminum , so we 'll call it eka-aluminum , `` eka '' being sanskrit for one . nobody 's found eka-aluminum yet , so we do n't know anything about it , right ? wrong ! based on where it 's located , i can tell you all about it . first of all , an atom of eka-aluminum has an atomic weight of 68 , about 68 times heavier than a hydrogen atom . when eka-aluminum is isolated , you 'll see it 's a solid metal at room temperature . it 's shiny , it conducts heat really well , it can be flattened into a sheet , stretched into a wire , but its melting point is low . like , freakishly low . oh , and a cubic centimeter of it will weigh six grams . mendeleev could predict all of these things simply from where the blank spot was , and his understanding of how the elements surrounding it behave . a few years after this prediction , a french guy named paul emile lecoq de boisbaudran discovered a new element in ore samples and named it gallium after gaul , the historical name for france . gallium is one step away from aluminum on the periodic table . it 's eka-aluminum . so were mendeleev 's predictions right ? gallium 's atomic weight is 69.72 . a cubic centimeter of it weighs 5.9 grams . it 's a solid metal at room temperature , but it melts at a paltry 30 degrees celcius , 85 degrees fahrenheit . it melts in your mouth and in your hand . not only did mendeleev completely nail gallium , he predicted other elements that were unknown at the time : scandium , germanium , rhenium . the element he called eka-manganese is now called technetium . technetium is so rare it could n't be isolated until it was synthesized in a cyclotron in 1937 , almost 70 years after dmitri predicted its existence , 30 years after he died . dmitri died without a nobel prize in 1907 , but he wound up receiving a much more exclusive honor . in 1955 , scientists at uc berkeley successfully created 17 atoms of a previously undiscovered element . this element filled an empty spot in the perodic table at number 101 , and was officially named mendelevium in 1963 . there have been well over 800 nobel prize winners , but only 15 scientists have an element named after them . so the next time you stare at a periodic table , whether it 's on the wall of a university classroom or on a five-dollar coffee mug , dmitri mendeleev , the architect of the periodic table , will be staring back .
|
it 's not just in every chemistry lab worldwide , it 's found on t-shirts , coffee mugs , and shower curtains . but the periodic table is n't just another trendy icon . it 's a massive slab of human genius , up there with the taj mahal , the mona lisa , and the ice cream sandwich -- and the table 's creator , dmitri mendeleev , is a bonafide science hall-of-famer .
|
lots of scientists had worked on the periodic table other than mendeleev . what do you think would have changed had they all worked closely together to figure out the best way to arrange the periodic table ? do you think collaboration is always the best answer ?
|
when we hear the word radiation , it 's tempting to picture huge explosions and frightening mutations , but that 's not the full story . radiation also applies to rainbows and a doctor examining an x-ray . so what is radiation really , and how much should we worry about its effects ? the answer begins with understanding that the word radiation describes two very different scientific phenomena : electromagnetic radiation and nuclear radiation . electromagnetic radiation is pure energy consisting of interacting electrical and magnetic waves oscillating through space . as these waves oscillate faster , they scale up in energy . at the lower end of the spectrum , there 's radio , infrared , and visible light . at the higher end are ultraviolet , x-ray , and gamma rays . modern society is shaped by sending and detecting electromagnetic radiation . we might download an email to our phone via radio waves to open an image of an x-ray print , which we can see because our screen emits visible light . nuclear radiation , on the other hand , originates in the atomic nucleus , where protons repel each other due to their mutually positive charges . a phenomenon known as the strong nuclear force struggles to overcome this repulsion and keep the nucleus intact . however , some combinations of protons and neutrons , known as isotopes , remain unstable , or radioactive . they will randomly eject matter and/or energy , known as nuclear radiation , to achieve greater stability . nuclear radiation comes from natural sources , like radon , a gas which seeps up from the ground . we also refine naturally occurring radioactive ores to fuel nuclear power plants . even bananas contain trace amounts of a radioactive potassium isotope . so if we live in a world of radiation , how can we escape its dangerous effects ? to start , not all radiation is hazardous . radiation becomes risky when it rips atoms ' electrons away upon impact , a process that can damage dna . this is known as ionizing radiation because an atom that has lost or gained electrons is called an ion . all nuclear radiation is ionizing , while only the highest energy electromagnetic radiation is . that includes gamma rays , x-rays , and the high-energy end of ultraviolet . that 's why as an extra precaution during x-rays , doctors shield body parts they do n't need to examine , and why beach-goers use sunscreen . in comparison , cell phones and microwaves operate at the lower end of the spectrum , so there is no risk of ionizing radiation from their use . the biggest health risk occurs when lots of ionizing radiation hits us in a short time period , also known as an acute exposure . acute exposures overwhelm the body 's natural ability to repair the damage . this can trigger cancers , cellular dysfunction , and potentially even death . fortunately , acute exposures are rare , but we are exposed daily to lower levels of ionizing radiation from both natural and man-made sources . scientists have a harder time quantifying these risks . your body often repairs damage from small amounts ionizing radiation , and if it ca n't , the results of damage may not manifest for a decade or more . one way scientists compare ionizing radiation exposure is a unit called the sievert . an acute exposure to one sievert will probably cause nausea within hours , and four sieverts could be fatal . however , our normal daily exposures are far lower . the average person receives 6.2 millisieverts of radiation from all sources annually , around a third due to radon . at only five microsieverts each , you 'd need to get more than 1200 dental x-rays to rack up your annual dosage . and remember that banana ? if you could absorb all the banana 's radiation , you 'd need around 170 a day to hit your annual dosage . we live in a world of radiation . however , much of that radiation is non-ionizing . for the remainder that is ionizing , our exposures are usually low , and choices like getting your home tested for radon and wearing sunscreen can help reduce the associated health risks . marie curie , one of the early radiation pioneers , summed up the challenge as follows : `` nothing in life is to be feared , it is only to be understood . now is the time to understand more , so that we may fear less . ''
|
this is known as ionizing radiation because an atom that has lost or gained electrons is called an ion . all nuclear radiation is ionizing , while only the highest energy electromagnetic radiation is . that includes gamma rays , x-rays , and the high-energy end of ultraviolet .
|
sometimes when a nucleus decays , it ejects a packet of pure energy known as a gamma ray . which type of radiation is a gamma ray : electromagnetic or nuclear ?
|
now , my subject is success , so people sometimes call me a `` motivational speaker . '' but i want you to know right up front i 'm not a motivational speaker . i could n't pass the height requirement . ( laughter ) and i could n't motivate anybody . my employees actually call me a de-motivational speaker . ( laughter ) what i try to be is an informational speaker . i went out and found out some information about success , and i 'm just here to pass it on . and my story started over ten years ago , on a plane . i was on my way to the ted conference in california , and in the seat next to me was a teenage girl , and she came from a really poor family , but she wanted to get somewhere in life . and as i tapped away on my computer , she kept asking me questions , and then out of the blue , she asked , `` are you successful ? '' i said , `` no , i 'm not successful . '' terry fox , my hero , now there 's a big success . he lost a leg to cancer , then ran thousands of miles and raised millions for cancer research . or bill gates , a guy who owns his own plane and does n't have to sit next to some kid asking him questions . ( laughter ) but then i told her about some of the stuff i 'd done . i love communications , and i 've won lots of awards in marketing . i love running , and i still sometimes win my age group , old farts over 60 . ( laughter ) my fastest marathon is two hours and 43 minutes to run the 26 miles , or 42 kilometers . i 've run over 50 marathons , in all 7 continents . this was a run my wife and i did up the inca trail to machu picchu in peru . and to qualify for the 7 continents , we had to run a marathon in antarctica . but when we got there , it did n't look nice and calm like this , it looked like this . the waves were so high , we could n't get to shore . so we sailed 200 miles further south to where the seas were calm and ran the entire 26-mile marathon on the boat . 422 laps around the deck of that little boat . my wife and i have also climbed two of the world 's seven summits , the highest mountains on each continent . we climbed aconcagua , the highest mountain on the american continent , and kilimanjaro , the highest mountain in africa . well , to be honest , i puked my way to the top of kilimanjaro , i got altitude sickness . i got no sympathy from my wife . she passed me and did a lap around the top while i was still struggling up there . in spite of that , we 're still together and have been for over 35 years . ( applause ) i 'd say that 's a success these days . so i said to the girl , `` well , you know , i guess i have had some success . '' and then she said , `` okay , so are you a millionaire ? '' ( laughter ) now , i did n't know what to say , because when i grew up , it was bad manners to talk about money . but i figured i 'd better be honest , and i said , `` yeah . i 'm a millionaire . but i do n't know how it happened . i never went after the money , and it 's not that important to me . '' she said , `` maybe not to you , but it is to me . i do n't want to be poor all my life . i want to get somewhere , but it 's never going to happen . '' i said , `` well , why not ? '' she said , `` well , you know , i 'm not very smart . i 'm not doing great in school . '' i said , `` so what ? i 'm not smart . i barely passed high school . i had absolutely nothing going for me . i was never voted most popular or most likely to succeed . i started a whole new category -- most likely to fail . but in the end , i did okay . so if i can do it , you can do it . '' and then she asked me the big question : `` okay , so what really leads to success ? '' i said , `` jeez , sorry . i do n't know . i guess somehow i did it . i do n't know how i did it . '' so i get off the plane and go to the ted conference , and i 'm standing in a room full of extraordinarily successful people in many fields -- business , science , arts , health , technology , the environment -- when it hit me : why do n't i ask them what helped them succeed , and find out what really leads to success for everyone ? so i was all excited to get out there and start talking to these great people , when the self-doubt set in . i mean , why would people want to talk to me ? i 'm not a famous journalist . i 'm not even a journalist . so i was ready to stop the project before it even began , when who comes walking towards me but ben cohen , the famous co-founder of ben and jerry 's ice cream . i figured it was now or never . i pushed through the self-doubt , jumped out in front of him , and said , `` ben , i 'm working on this project . i do n't even know what to ask you , but can you tell me what helped you succeed ? '' he said , `` yeah , sure , come on . let 's go for a coffee . '' and over coffee and ice cream , ben told me his story . now here we are over 10 years later , and i 've interviewed over 500 successful people face-to-face , and collected thousands of other success stories . i wanted to find the common factors for success in all fields , so i had to interview people in careers ranging from a to z . these are just the careers i interviewed beginning with the letter a , and in most cases more than one person . i interviewed six successful accountants , five corporate auditors , five astronauts who had been into space , four actors who had won the academy award for best actor , three of the world 's top astrophysicists , six of the world 's leading architects and , oh yeah , four nobel prize winners . yeah , i know it does n't start with a , but it 's kind of cool . ( laughter ) and i want to say a sincere thanks to all the great people that i 've interviewed over the years . this really is their story ; i 'm just the messenger . the really big job was taking all the interviews and analyzing them , word by word , line by line , and sorting them into all the factors that people said helped them succeed . and then you start to see the big factors that are common to most people 's success . altogether , i analyzed and sorted millions of words . do you know how much work that is ? that 's all i do , day and night -- sort and analyze . i 'll tell you , if i ever get my hands on that kid on the plane -- ( laughter ) actually , if i do , i 'll thank her . because i 've never had so much fun and met so many interesting people . and now , i can answer her question . i discovered the 8 traits successful people have in common , or the 8 to be great : love what you do ; work really hard ; focus on one thing , not everything ; keep pushing yourself ; come up with good ideas ; keep improving yourself and what you do ; serve others something of value , because success is n't just about me , me , me ; and persist , because there 's no overnight success . why did i pick these ? because when i added up all the comments in my interviews , more people said those 8 things helped them than anything else . the eight traits are really the heart of success , the foundation , and then on top we build the specific skills that we need for our particular field or career . technical skills , analytical skills , people skills , creative skills -- lots of other skills we can add on top , depending on our field . but no matter what field we 're in , these eight traits will be at the heart of our success . ( applause )
|
so if i can do it , you can do it . '' and then she asked me the big question : `` okay , so what really leads to success ? '' i said , `` jeez , sorry .
|
what was the question i was asked ?
|
if someone asked you who the richest people in history were , who would you name ? perhaps a billionaire banker or corporate mogul , like bill gates or john d. rockefeller . how about african king musa keita i ? ruling the mali empire in the 14th century ce , mansa musa , or the king of kings , amassed a fortune that possibly made him one of the wealthiest people who ever lived . but his vast wealth was only one piece of his rich legacy . when mansa musa came to power in 1312 , much of europe was racked by famine and civil wars . but many african kingdoms and the islamic world were flourishing , and mansa musa played a great role in bringing the fruits of this flourishing to his own realm . by strategically annexing the city of timbuktu , and reestablishing power over the city of gao , he gained control over important trade routes between the mediterranean and the west african coast , continuing a period of expansion , which dramatically increased mali 's size . the territory of the mali empire was rich in natural resources , such as gold and salt . the world first witnessed the extent of mansa musa 's wealth in 1324 when he took his pilgrimage to mecca . not one to travel on a budget , he brought a caravan stretching as far as the eye could see . accounts of this journey are mostly based on an oral testimony and differing written records , so it 's difficult to determine the exact details . but what most agree on is the extravagant scale of the excursion . chroniclers describe an entourage of tens of thousands of soldiers , civilians , and slaves , 500 heralds bearing gold staffs and dressed in fine silks , and many camels and horses bearing an abundance of gold bars . stopping in cities such as cairo , mansa musa is said to have spent massive quantities of gold , giving to the poor , buying souvenirs , and even having mosques built along the way . in fact , his spending may have destabilized the regional economy , causing mass inflation . this journey reportedly took over a year , and by the time mansa musa returned , tales of his amazing wealth had spread to the ports of the mediterranean . mali and its king were elevated to near legendary status , cemented by their inclusion on the 1375 catalan atlas . one of the most important world maps of medieval europe , it depicted the king holding a scepter and a gleaming gold nugget . mansa musa had literally put his empire and himself on the map . but material riches were n't the king 's only concern . as a devout muslim , he took a particular interest in timbuktu , already a center of religion and learning prior to its annexation . upon returning from his pilgrimage , he had the great djinguereber mosque built there with the help of an andalusian architect . he also established a major university , further elevating the city 's reputation , and attracting scholars and students from all over the islamic world . under mansa musa , the empire became urbanized , with schools and mosques in hundreds of densely populated towns . the king 's rich legacy persisted for generations and to this day , there are mausoleums , libraries and mosques that stand as a testament to this golden age of mali 's history .
|
but his vast wealth was only one piece of his rich legacy . when mansa musa came to power in 1312 , much of europe was racked by famine and civil wars . but many african kingdoms and the islamic world were flourishing , and mansa musa played a great role in bringing the fruits of this flourishing to his own realm .
|
in which year did mansa musa come into power ?
|
what keeps us healthy and happy as we go through life ? if you were going to invest now in your future best self , where would you put your time and your energy ? there was a recent survey of millennials asking them what their most important life goals were , and over 80 percent said that a major life goal for them was to get rich . and another 50 percent of those same young adults said that another major life goal was to become famous . ( laughter ) and we 're constantly told to lean in to work , to push harder and achieve more . we 're given the impression that these are the things that we need to go after in order to have a good life . pictures of entire lives , of the choices that people make and how those choices work out for them , those pictures are almost impossible to get . most of what we know about human life we know from asking people to remember the past , and as we know , hindsight is anything but 20/20 . we forget vast amounts of what happens to us in life , and sometimes memory is downright creative . but what if we could watch entire lives as they unfold through time ? what if we could study people from the time that they were teenagers all the way into old age to see what really keeps people happy and healthy ? we did that . the harvard study of adult development may be the longest study of adult life that 's ever been done . for 75 years , we 've tracked the lives of 724 men , year after year , asking about their work , their home lives , their health , and of course asking all along the way without knowing how their life stories were going to turn out . studies like this are exceedingly rare . almost all projects of this kind fall apart within a decade because too many people drop out of the study , or funding for the research dries up , or the researchers get distracted , or they die , and nobody moves the ball further down the field . but through a combination of luck and the persistence of several generations of researchers , this study has survived . about 60 of our original 724 men are still alive , still participating in the study , most of them in their 90s . and we are now beginning to study the more than 2,000 children of these men . and i 'm the fourth director of the study . since 1938 , we 've tracked the lives of two groups of men . the first group started in the study when they were sophomores at harvard college . they all finished college during world war ii , and then most went off to serve in the war . and the second group that we 've followed was a group of boys from boston 's poorest neighborhoods , boys who were chosen for the study specifically because they were from some of the most troubled and disadvantaged families in the boston of the 1930s . most lived in tenements , many without hot and cold running water . when they entered the study , all of these teenagers were interviewed . they were given medical exams . we went to their homes and we interviewed their parents . and then these teenagers grew up into adults who entered all walks of life . they became factory workers and lawyers and bricklayers and doctors , one president of the united states . some developed alcoholism . a few developed schizophrenia . some climbed the social ladder from the bottom all the way to the very top , and some made that journey in the opposite direction . the founders of this study would never in their wildest dreams have imagined that i would be standing here today , 75 years later , telling you that the study still continues . every two years , our patient and dedicated research staff calls up our men and asks them if we can send them yet one more set of questions about their lives . many of the inner city boston men ask us , `` why do you keep wanting to study me ? my life just is n't that interesting . '' the harvard men never ask that question . ( laughter ) to get the clearest picture of these lives , we do n't just send them questionnaires . we interview them in their living rooms . we get their medical records from their doctors . we draw their blood , we scan their brains , we talk to their children . we videotape them talking with their wives about their deepest concerns . and when , about a decade ago , we finally asked the wives if they would join us as members of the study , many of the women said , `` you know , it 's about time . '' ( laughter ) so what have we learned ? what are the lessons that come from the tens of thousands of pages of information that we 've generated on these lives ? well , the lessons are n't about wealth or fame or working harder and harder . the clearest message that we get from this 75-year study is this : good relationships keep us happier and healthier . period . we 've learned three big lessons about relationships . the first is that social connections are really good for us , and that loneliness kills . it turns out that people who are more socially connected to family , to friends , to community , are happier , they 're physically healthier , and they live longer than people who are less well connected . and the experience of loneliness turns out to be toxic . people who are more isolated than they want to be from others find that they are less happy , their health declines earlier in midlife , their brain functioning declines sooner and they live shorter lives than people who are not lonely . and the sad fact is that at any given time , more than one in five americans will report that they 're lonely . and we know that you can be lonely in a crowd and you can be lonely in a marriage , so the second big lesson that we learned is that it 's not just the number of friends you have , and it 's not whether or not you 're in a committed relationship , but it 's the quality of your close relationships that matters . it turns out that living in the midst of conflict is really bad for our health . high-conflict marriages , for example , without much affection , turn out to be very bad for our health , perhaps worse than getting divorced . and living in the midst of good , warm relationships is protective . once we had followed our men all the way into their 80s , we wanted to look back at them at midlife and to see if we could predict who was going to grow into a happy , healthy octogenarian and who was n't . and when we gathered together everything we knew about them at age 50 , it was n't their middle age cholesterol levels that predicted how they were going to grow old . it was how satisfied they were in their relationships . the people who were the most satisfied in their relationships at age 50 were the healthiest at age 80 . and good , close relationships seem to buffer us from some of the slings and arrows of getting old . our most happily partnered men and women reported , in their 80s , that on the days when they had more physical pain , their mood stayed just as happy . but the people who were in unhappy relationships , on the days when they reported more physical pain , it was magnified by more emotional pain . and the third big lesson that we learned about relationships and our health is that good relationships do n't just protect our bodies , they protect our brains . it turns out that being in a securely attached relationship to another person in your 80s is protective , that the people who are in relationships where they really feel they can count on the other person in times of need , those people 's memories stay sharper longer . and the people in relationships where they feel they really ca n't count on the other one , those are the people who experience earlier memory decline . and those good relationships , they do n't have to be smooth all the time . some of our octogenarian couples could bicker with each other day in and day out , but as long as they felt that they could really count on the other when the going got tough , those arguments did n't take a toll on their memories . so this message , that good , close relationships are good for our health and well-being , this is wisdom that 's as old as the hills . why is this so hard to get and so easy to ignore ? well , we 're human . what we 'd really like is a quick fix , something we can get that 'll make our lives good and keep them that way . relationships are messy and they 're complicated and the hard work of tending to family and friends , it 's not sexy or glamorous . it 's also lifelong . it never ends . the people in our 75-year study who were the happiest in retirement were the people who had actively worked to replace workmates with new playmates . just like the millennials in that recent survey , many of our men when they were starting out as young adults really believed that fame and wealth and high achievement were what they needed to go after to have a good life . but over and over , over these 75 years , our study has shown that the people who fared the best were the people who leaned in to relationships , with family , with friends , with community . so what about you ? let 's say you 're 25 , or you 're 40 , or you 're 60 . what might leaning in to relationships even look like ? well , the possibilities are practically endless . it might be something as simple as replacing screen time with people time or livening up a stale relationship by doing something new together , long walks or date nights , or reaching out to that family member who you have n't spoken to in years , because those all-too-common family feuds take a terrible toll on the people who hold the grudges . i 'd like to close with a quote from mark twain . more than a century ago , he was looking back on his life , and he wrote this : `` there is n't time , so brief is life , for bickerings , apologies , heartburnings , callings to account . there is only time for loving , and but an instant , so to speak , for that . '' the good life is built with good relationships . thank you . ( applause )
|
we did that . the harvard study of adult development may be the longest study of adult life that 's ever been done . for 75 years , we 've tracked the lives of 724 men , year after year , asking about their work , their home lives , their health , and of course asking all along the way without knowing how their life stories were going to turn out .
|
how long has the harvard study of adult development been tracking the lives of 724 men ?
|
translator : andrea mcdonough reviewer : bedirhan cinar about 100 days ago , we landed a two-ton suv on the surface of another planet , on the surface of mars . this is one of the first pictures we took there with our rover , looking out at mount sharp . i kind of cry a little bit , choke up , when i see this picture . why mars and why do we look at these other planets ? part of it is to understand our own planet -- what 's the context for us ? we live on this amazing planet , but mars is a lot like earth . it 's similar in size . during the daytime , it can get up to 70 degrees fahrenheit . so , it 's so like earth , but at the same time , this is a barren landscape . you do n't see any trees , you do n't see any cactuses growing , anything like that . today i 'm going to tell you about how we got from earth to mars and why it 's so cool . so one of the things we start with is a blank sheet of paper . we knew from the previous missions in 2004 , spirit and opportunity , there was water on mars in the past . but what 's the next step ? we 're looking for an even more fundamental level of , what does it take to have life survive ? and so , to have that kind of knowledge and understanding , we have to carry a mass amount of instruments . we have to carry the kind of labs that people have whole rooms devoted to on earth inside of , essentially , a small car . and we shrunk it all down to something that weighs about as much as i do , and then put it inside of this rover that weighs as much as your car does . and that rover is now on the surface of mars , but it 's so heavy , and so it kind of takes a special challenge for us to make it all work and come together . so we look at our tool of , what do we have to land stuff on mars ? and one of the options is airbags . we 've done it before . airbags are pretty cool , they bounce around a lot . you could never put a human inside of an airbag , because they would get squashed . but the problem with airbags is , the airbags you see here , which landed the smaller rover -- it 's like 400 pounds , the entire rover -- were about the size of this room . so you can imagine the size of airbags it would take to land a two-ton rover on mars . and they 'd have to be made out of materials that do n't even exist today , so it 'd be some kind of exotic material that we 'd have to develop and it may or may not work . so , what about rockets ? you know , you see all the rocket ships landing in old movies , all rockets on the bottom -- it 's a cool idea . it works when they 're pretty light still , but the problem is , these rockets have to be pretty strong to actually softly land you on mars . and so they would be so powerful they could dig holes into the ground and then you would just end up inside of a hole and not be able to drive out of it . so , not the best design . but what if i could take the rockets and move them up ? and that 's what we came up with . it 's a rocket-powered jet pack ; we call it the sky crane . basically , this big rocket sits on top of our rover and when we 're ready to land , the rocket hovers in place and we slowly lower the rover to the ground . and then we touch down , we 're actually on the wheels , we 're ready to drive , day one . but in addition to that , the scientists were like , `` we actually want to go somewhere interesting . '' the last two missions were cool , but they basically landed in what was like landing in the plains or desert . not very exciting . we all know from the exciting places on earth like the grand canyon , those are , for the scientists , the most interesting , because you see that whole layer , you see years and years of history all in one place . the same thing is true for where we landed . we wanted to land somewhere that was unique , that had this crater wall where things had been dug up for us , where mountains were pushing things up . but the problem is , if you landed with the older systems , you could 've landed on the side of that mountain and just tumbled off , could 've been the side of a cliff , the crater wall or a large boulder . so we needed a kind of technology to help us land in a very small area , and that was this little guided entry from apollo . we took it from the 1960s . we flew over like the manned vehicle , because they have to pick up men , you ca n't just land all over the place . and then we landed , like , spot-on in the middle . and in fact , it was so spot-on that when we did it , it was basically like a quarterback launching towards mars -- like a quarterback , though , that was in seattle , throwing at a receiver that was moving here in giants stadium . that 's how accurate we were . kind of awesome . but you only get one shot , and so we actually have to design a system that we can build and test and operate , and so it 's not just about can we get it to mars , but , if it 's only one chance , how do you make sure that one chance goes well ? so there 's all these processes to make sure things are built properly . then we go out to the desert and drive around and test it . we fly things in f-18s to make sure the radar systems work in high speeds . then , most importantly , we test the team to make sure they know how to operate it . we do n't want to miss it because we sent the wrong command and now it 's going to be rebooting forever . so , that guy fred there , he did a lot of that . and then we launched it on this rocket to mars . we landed 2,000 pounds on mars , but the entire thing was about 10,000 pounds when we lifted off from earth , all the fuel and the solar arrays and everything else that we needed . and , again , we were so accurate that we landed in this , like , little pin-point on mars . in the meantime , though , we had to design a landing system that worked . and i told you about the actual physics of it , but here 's the catch : mars is about 14 minutes away from earth in light speed , which means if i try to control it with a joystick , i would be always controlling to 14 minutes in advance , so it would n't work . so we had to give it all the smarts and knowledge it needed to make it happen . so we built in all these smarts and algorithms and told it here 's what you 're going to have to do , and it goes from basically five times the speed of a speeding bullet to about a baby 's crawl , all within about seven minutes , which are called the seven minutes of terror , because i was about to throw up . ( laughter ) but today we 're on the surface of mars , and this was one of the panoramas we took a couple days after we landed , and it 's amazing to me , because you look at this , and can see the grand canyon , you can see your own planet , you can imagine walking on the surface . and so what we 're going to do and continue to do is to understand what makes mars so special and what makes earth even more special that we 're all here together today . so we 'll see where curiosity takes us -- not just our rover , but our sense of exploration . thank you . ( applause )
|
translator : andrea mcdonough reviewer : bedirhan cinar about 100 days ago , we landed a two-ton suv on the surface of another planet , on the surface of mars . this is one of the first pictures we took there with our rover , looking out at mount sharp .
|
why do you think we will ( or why do you think we will not ) realize the age of star wars / star trek ?
|
you know , i had a real rough time in school with add , and i have a phd . i earned a phd , but ... tough to pay attention -- biology , geology , physics , chemistry -- really tough for me . only one thing grabbed my attention , and it 's that planet called earth . but in this picture here , you 'll see that earth is mostly water . that 's the pacific . seventy percent of earth is covered with water . you can say , `` hey , i know earth . i live here . '' you do n't know earth . you do n't know this planet , because most of it 's covered with that -- average depth , two miles . and when you go outside and look up at the empire state building , chrysler building , the average depth of the ocean is 15 of those on top of one another . we 've explored about five percent of what 's in that water . `` explored , '' meaning , for the first time , go peek and see what 's there . so what i want to do today is show you some things about this planet , about the oceans . i want to take you from shallow water down to the deep water , and hopefully , like me , you 'll see some things that get you hooked on exploring planet earth . you know things like corals ; you 've seen plenty of corals , those of you who 've been to the beach , snorkeling , know corals are an amazing place to go -- full of life , some big animals , small animals , some nice , some dangerous , sharks , whales , all that stuff . they need to be protected from humanity . they 're great places . but what you probably do n't know is in the very deep part of the ocean , we have volcanic eruptions . most volcanoes on earth are at the bottom of the sea -- more than 80 percent . and we actually have fire , fire deep inside the ocean , going on right now . all over the world -- in the pacific , the atlantic , the indian ocean . in this place , the ocean floor , the rocks actually turn to liquid . so you actually have waves on the ocean floor . you 'd say nothing could live there , but when we look in detail , even there , in the deepest , darkest places on earth , we find life , which tells us that life really wants to happen . so , pretty amazing stuff . every time we go to the bottom of the sea , we explore with our submarines , with our robots , we see something that 's usually surprising , sometimes it 's startling and sometimes revolutionary . you see that puddle of water sitting there . and all around the water there 's a little cliff , there 's a little white sandy beach . we 'll get closer , you 'll see the beach a little bit better , some of the waves in that water , down there . the thing that 's special about this water is that it 's at the bottom of the gulf of mexico . so you 're sitting inside a submarine , looking out the window at a little pond of water beneath the sea . we see ponds , we see lakes , we see rivers -- in fact , right here is a river at the bottom of the ocean going from the lower left to the upper right . water is actually flowing through there . this totally blew our minds . how can you have this at the bottom ? you 're in the ocean looking at more water . and there 's animals that only live in that water . so , the bottom of the ocean -- i love this map , because it shows in the middle of the ocean , there 's a mountain range . it 's the greatest mountain range on earth , called the mid-ocean ridge -- 50,000 miles long , and we 've hardly had a peek at it . hardly had a peek at it . we find valleys , many thousands of valleys , larger , wider , deeper than the grand canyon . we find , as i said , underwater lakes , rivers , waterfalls . the largest waterfall on the planet is actually under the ocean , up near iceland . all that stuff is in that five percent that we 've explored . so the deal about the ocean is that to explore it , you 've got to have technology . not only technology , but it 's not just dave gallo or one person exploring , it 's a team of people . you 've got to have the talent , the team . you 've got to have the technology . in this case , it 's our ship , atlantis , and the submarine , alvin . inside that submarine -- this is an alvin launch -- there 's three people . they 're being wheeled out onto deck . there 's 47 other people , the teamwork on that ship , making sure that these people are okay . everybody in that submarine is thinking one thing right now : should i have gone to the bathroom one more time ? because you 're in there for 10 hours -- 10 hours in that little sphere . three of you together and nobody is going to be around you . you go into the water and once you hit the water , it 's amazing . there 's a lovely color blue that penetrates right inside you . you do n't hear the surface ship anymore , you hear that pinging of a sonar . if you 've got an iphone you 've got sonar on there -- it 's that same pinging that goes down to the bottom and comes back up . divers check out the sub to make sure the outside is okay , and then they say `` go , '' and down you go to the bottom of the ocean and it 's an amazing trip . so for two and a half hours , you sink down to the bottom . and two hours of it is totally pitch black . we thought that nothing could live inside that world at the bottom of the ocean . and when we look , we find some amazing things . all the way down -- we call it the mid-water -- from the top of the ocean down to the bottom , we find life . whenever we stop and look , we find life . i 'm going to show you some jellies . they 're absolutely some of the coolest creatures on earth . look at that thing , just flailing his arms around . that 's like a little lobster . that one is like all these animals with their mouths hooked together , the colonial animals . some animals are tiny , some can be longer than this stage . just amazing animals . and you ca n't collect them with a net -- we have to go with our cameras and take a look at them . so every time we go , new species of life . the ocean is full of life . and yet the deepest part of the ocean -- when we go to that mountain range , we find hot springs . now we were sure -- because this is poisonous water , because it 's so deep it would crush the titanic the same way you crush an empty cup in your hand -- we were sure there would be no life there at all . instead , we find more life and diversity and density than in the tropical rainforest . so , in one instance , in one peek out the window of the sub , we discover something that revolutionizes the way we think about life on earth ; and that is , you do n't always have to have sunlight to get life going . there 's big animals down there too , some that look familiar . that guy 's called dumbo . i love him . dumbo 's great . this guy -- oh man , i wish i had more footage of this . we 're trying to get an expedition together to go look at this and maybe in a year we 'll have that . go online and look . vampyroteuthis infernalis . the vampire squid . incredibly cool . in the darkness of the deep sea , he 's got glowing tentacles , so if i 'm coming at you like him , i put my arms out in the darkness so all you see are little glowing things over here . meanwhile , i 'm coming at you . when he wants to escape , he 's got these glowing pods on his butt that look like eyes . glowing eyes on his butt . how cool is that ? just an amazing animal . ( laughter ) `` vampire '' squid , because when it gets protective , it pulls this black cape over its whole body , and curls up into a ball . outrageous animal . this ship , `` the ship of dreams '' -- a hundred years ago this coming april , this ship was supposed to show up in new york . it 's the titanic . i co-led an expedition out there last year . we are learning so much about that ship . the titanic is an interesting place for biology , because animals are moving in to live on the titanic . microbes are actually eating the hull of the titanic . that 's where jack was king of the world there on the bow of the titanic . so we 're doing real good . and what 's exciting to me is that we 're making a virtual titanic , so you can sit there at home with your joystick and your headset on , and you can actually explore the titanic for yourself . that 's what we want to do , make these virtual worlds , so it 's not dave gallo or someone else exploring the world ; it 's you . you explore it for yourself . so here 's the bottom line : the oceans are unexplored and i ca n't begin to tell you how important that is , because they 're important to us . seven billion people live on this planet and all of us are impacted by the sea , because the oceans control the air you breathe , the water you drink , the food you eat . all those are controlled in some way by the ocean , and this is a thing that we have n't even explored -- five percent . the thing i want to leave you with is , in that five percent , i showed you some cool stuff . there 's a lot more cool stuff -- every dive we go on in the ocean , we find something new about the sea . so what 's in that other 95 percent ? did we get the exciting stuff or is there more out there ? and i 'm here to tell you that the ocean is full of surprises . there 's a quote i love by marcel proust : `` the true voyage of exploration is not so much in seeking new landscapes , '' which we do , `` but in having new eyes . '' and so i hope today , by showing you some of this , it 's given you some new eyes about this planet , and for the first time , i want you to think about it differently . thank you very much . thank you . ( applause )
|
so , the bottom of the ocean -- i love this map , because it shows in the middle of the ocean , there 's a mountain range . it 's the greatest mountain range on earth , called the mid-ocean ridge -- 50,000 miles long , and we 've hardly had a peek at it . hardly had a peek at it .
|
the mid-ocean ridge is
|
as 1905 dawned , the soon-to-be 26-year-old albert einstein faced life as a failed academic . most physicists of the time would have scoffed at the idea that this minor civil servant could have much to contribute to science . yet within the following year , einstein would publish not one , not two , not three , but four extraordinary papers , each on a different topic , that were destined to radically transform our understanding of the universe . the myth that einstein had failed math is just that . he had mastered calculus on his own by the age of 15 and done well at both his munich secondary school and at the swiss polytechnic , where he studied for a math and physics teaching diploma . but skipping classes to spend more time in the lab and neglecting to show proper deference to his professors had derailed his intended career path . passed over even for a lab assistant position , he had to settle for a job at the swiss patent office , obtained with the help of a friend 's father . working six days a week as a patent clerk , einstein still managed to make some time for physics , discussing the latest work with a few close friends , and publishing a couple of minor papers . it came as a major surprise when in march 1905 he submitted a paper with a shocking hypothesis . despite decades of evidence that light was a wave , einstein proposed that it could , in fact , be a particle , showing that mysterious phenomena , such as the photoelectric effect , could be explained by his hypothesis . the idea was derided for years to come , but einstein was simply twenty years ahead of his time . wave-particle duality was slated to become a cornerstone of the quantum revolution . two months later in may , einstein submitted a second paper , this time tackling the centuries old question of whether atoms actually exist . though certain theories were built on the idea of invisible atoms , some prominent scientists still believed them to be a useful fiction , rather than actual physical objects . but einstein used an ingenious argument , showing that the behavior of small particles randomly moving around in a liquid , known as brownian motion , could be precisely predicted by the collisions of millions of invisible atoms . experiments soon confirmed einstein 's model , and atomic skeptics threw in the towel . the third paper came in june . for a long time , einstein had been troubled by an inconsistency between two fundamental principles of physics . the well established principle of relativity , going all the way back to galileo , stated that absolute motion could not be defined . yet electromagnetic theory , also well established , asserted that absolute motion did exist . the discrepancy , and his inability to resolve it , left einstein in what he described as a state of psychic tension . but one day in may , after he had mulled over the puzzle with his friend michele besso , the clouds parted . einstein realized that the contradiction could be resolved if it was the speed of light that remained constant , regardless of reference frame , while both time and space were relative to the observer . it took einstein only a few weeks to work out the details and formulate what came to be known as special relativity . the theory not only shattered our previous understanding of reality but would also pave the way for technologies , ranging from particle accelerators , to the global positioning system . one might think that this was enough , but in september , a fourth paper arrived as a `` by the way '' follow-up to the special relativity paper . einstein had thought a little bit more about his theory , and realized it also implied that mass and energy , one apparently solid and the other supposedly ethereal , were actually equivalent . and their relationship could be expressed in what was to become the most famous and consequential equation in history : e=mc^2 . einstein would not become a world famous icon for nearly another fifteen years . it was only after his later general theory of relativity was confirmed in 1919 by measuring the bending of starlight during a solar eclipse that the press would turn him into a celebrity . but even if he had disappeared back into the patent office and accomplished nothing else after 1905 , those four papers of his miracle year would have remained the gold standard of startling unexpected genius .
|
the theory not only shattered our previous understanding of reality but would also pave the way for technologies , ranging from particle accelerators , to the global positioning system . one might think that this was enough , but in september , a fourth paper arrived as a `` by the way '' follow-up to the special relativity paper . einstein had thought a little bit more about his theory , and realized it also implied that mass and energy , one apparently solid and the other supposedly ethereal , were actually equivalent . and their relationship could be expressed in what was to become the most famous and consequential equation in history : e=mc^2 .
|
quotations attributed to einstein appear all over the place . though a good number are actually fake , he did have a way with words and left us with many pithy and profound sayings . the quotations below are authentic einstein ( in translation from german ) . which ones resonate with you the most , and why ? “ the important thing is not to stop questioning . curiosity has its own reason for existing . one can not help but be in awe when one contemplates the mystery of eternity , of life , of the marvelous structure of reality . it is enough if one tries to comprehend only a little of this mystery every day. ” “ one should not pursue goals that are easily achieved . one must develop an instinct for what one can just barely achieve through one ’ s greatest efforts. ” “ it strikes me as unfair , and even in bad taste , to select a few individuals for boundless admiration , attributing superhuman powers of mind and character to them . this has been my fate , and the contrast between the popular assessment of my powers and achievements and the reality is simply grotesque. ” “ try to become not a person of success , but try rather to become a person of value. ” “ it ’ s not that i ’ m so smart , it ’ s just that i stay with problems longer. ” ( though this remark is often attributed to einstein , he probably did not say it . but it is something he could have said because the second part about tenacity and resilience was true about him . )
|
where does bread get its fluffiness ? swiss cheese its holes ? and what makes vinegar so sour ? these foods may taste completely different , but all of these phenomena come from tiny organisms chowing down on sugar and belching up some culinary byproducts . let 's start with yeast . yeast are single-celled fungi used to make bread , beer , and wine , among other products . yeast break down carbohydrates , like sugar , to get energy and the molecules they need to function . they have two different ways to do this : the oxygen-dependent , or aerobic , pathway , and the oxygen-independent , anaerobic pathway , which is also called fermentation . when you bake bread , yeast can use both pathways , but they normally prefer to start with the anaerobic process of fermentation . in this process , ethanol is produced in addition to co2 . no , bread is n't alcoholic . small amounts of alcohol that are secreted evaporate during baking . in the aerobic , or oxygen-dependent pathway , the yeast consume some of the sugar and produce carbon dioxide gas , or co2 , and water . in both processes , the co2 accumulates and creates tiny bubbles . these bubbles get trapped by gluten and create a sponge-like structure that gives the bread its soft texture . wine also relies on yeast . but a wine-making set-up keeps the oxygen levels low so that yeast consume sugar using fermentation , the anaerobic pathway . the process often starts with wild yeasts already hanging out on the grapes . but to get consistent results , most winemakers also add carefully selected strains of yeast that can tolerate high levels of alcohol . the yeast consume the sugar in the grape juice , and as the sugar level drops , the alcohol level rises . this does n't necessarily mean that sweeter wines have less alcohol . different types of grapes start with different amounts of sugar , and sugar can also be added . what happens to the carbon dioxide ? it just bubbles away through a vent . in carbonated alcoholic beverages , like champagne and beer , sealed containers are used in primary or secondary fermentation to keep the carbon dioxide in the bottle . wine also introduces us to our second type of food-producing microorganism : bacteria . a special strain of bacteria turns a tart compound in grape juice into softer tasting ones that are responsible for some of the flavors in red wines and chardonnays . another type of bacteria , called acetic acid bacteria , is n't so desirable in wine , but they have their function , too . if there 's oxygen around , these bacteria convert the ethanol in wine into , well , acetic acid . let this process continue and you 'll eventually get vinegar . bacteria are the key for cheese , too . to make cheese , milk is inoculated with bacteria . the bacteria gobble up the lactose , a kind of sugar , and produce lactic acid , along with many other chemicals . as the milk gets more and more acidic , its proteins start to aggregate and curdle . that 's why spoiled milk is clumpy . cheesemakers usually add an enzyme called rennet , naturally found inside of cows , goats , and some other mammals to help this process along . eventually , those little curdles turn into bigger curds , which are pressed to squeeze out the water , and create a firm cheese . different strains of bacteria make different kinds of cheese . for example , a species of bacteria that emits carbon dioxide is what gives swiss cheese its characteristic holes . some cheeses , brie and camembert , use another kind of microorganism , too : mold . so your kitchen functions as a sort of biotechnology lab manned by microorganisms that culture your cuisine . yogurt , soy sauce , sour cream , sauerkraut , kefir , kimchi , kombucha , cheddar , challah , pita , and naan . but maybe not all at the same dinner .
|
in both processes , the co2 accumulates and creates tiny bubbles . these bubbles get trapped by gluten and create a sponge-like structure that gives the bread its soft texture . wine also relies on yeast .
|
why is bread soft and airy ?
|
astronomers have discovered thousands of planets orbiting stars other than the sun . they come in all sizes , at different orbital distances from their stars . the closest of them are trillions of miles away , and even the largest are just fuzzy patches in the fields of high-powered telescopes . but if one of these planets is close in size to the earth and orbits not too close and too far away from its parent star , it could be rocky and warm enough to have oceans and perhaps life . astronomers discover these potentially habitable planets , and their eyes get big and wide . could one of these distant worlds carry the building blocks of life ? or even a living , breathing , civilization ? is the question , `` are we alone in the universe ? '' about to be answered ? but wait . maybe we should ask a different question first . should we try to find out if we 're alone in the universe ? if we do find the atmospheric fingerprints of life on one of these small , distant worlds , should we try to contact any beings who may live there ? is that wise ? three decades ago , nasa decided the answer was yes . voyager 1 and 2 were launched in 1977 to explore the giant planets in the solar system . each spacecraft carried a golden phonograph record , a time capsule of sorts that included clues and messages meant to convey the story of human civilization . the contents of these gold-plated copper disks were chosen by a committee chaired by american astronomer and author carl sagan . they included over 100 images , and a range of sounds from the natural world : ocean waves , thunder , the sounds of birds and whales . the records also included music from many different time periods and cultures , greetings in 55 languages , and messages from the president of the united states , and the un secretary general . they also included a map . each golden record displays the location of our solar system with respect to fourteen pulsars . their precise , unique frequencies were indicated so that intelligent , extraterrestrial lifeforms could use them to find the earth . many years later , renowned physicist stephen hawking said that it was a mistake to give an alien species a roadmap to our planet . hawking suspected that any extraterrestrial life probably was n't any more complex than microbes , but he warned that if an advanced alien species did visit earth , it could be as catastrophic as christopher columbus 's arrival was for the native americans . meanwhile , the golden records continue their journeys . in 1990 , both voyager spacecraft passed beyond the orbit of pluto . voyager 1 entered interstellar space in 2012 , and will reach the nearest stellar system in 40,000 years . if either spacecraft is discovered by extraterrestrial life , there 's a possibility that they could decipher the clues from the golden record and one day reach our planet . that 's particularly true if theirs is a much more technologically advanced civilization . that life could be benevolent , as we would hope to be if humans are one day able to achieve interstellar travel . or it could be hostile . searching for planets that might have life means staring into a great abyss . we 'll likely have no clear knowledge of the evolutionary stage , sentience , character , or intentions of the first form of life we discover . so it 's a risk to turn our eyes outwards . we risk our very way of life . but it may be a greater risk not to look , to deny the very pioneering spirits that help shape our own species . we are all born curious about the world and the universe . pursuing that curiosity is one of humankind 's greatest achievements . perhaps there is room to push the frontiers of science , provided that we cradle alongside our fervor another of humankind 's greatest assets : hope .
|
or it could be hostile . searching for planets that might have life means staring into a great abyss . we 'll likely have no clear knowledge of the evolutionary stage , sentience , character , or intentions of the first form of life we discover .
|
astronomers look for planets that might have climates that are warm enough for liquid water to flow on their surfaces , like it does on the earth . what else does life need to survive on earth ?
|
back in new york , i am the head of development for a non-profit called robin hood . when i 'm not fighting poverty , i 'm fighting fires as the assistant captain of a volunteer fire company . now in our town , where the volunteers supplement a highly skilled career staff , you have to get to the fire scene pretty early to get in on any action . i remember my first fire . i was the second volunteer on the scene , so there was a pretty good chance i was going to get in . but still it was a real footrace against the other volunteers to get to the captain in charge to find out what our assignments would be . when i found the captain , he was having a very engaging conversation with the homeowner , who was surely having one of the worst days of her life . here it was , the middle of the night , she was standing outside in the pouring rain , under an umbrella , in her pajamas , barefoot , while her house was in flames . the other volunteer who had arrived just before me -- let 's call him lex luther -- ( laughter ) got to the captain first and was asked to go inside and save the homeowner 's dog . the dog ! i was stunned with jealousy . here was some lawyer or money manager who , for the rest of his life , gets to tell people that he went into a burning building to save a living creature , just because he beat me by five seconds . well , i was next . the captain waved me over . he said , `` bezos , i need you to go into the house . i need you to go upstairs , past the fire , and i need you to get this woman a pair of shoes . '' ( laughter ) i swear . so , not exactly what i was hoping for , but off i went -- up the stairs , down the hall , past the 'real ' firefighters , who were pretty much done putting out the fire at this point , into the master bedroom to get a pair of shoes . now i know what you 're thinking , but i 'm no hero . ( laughter ) i carried my payload back downstairs where i met my nemesis and the precious dog by the front door . we took our treasures outside to the homeowner , where , not surprisingly , his received much more attention than did mine . a few weeks later , the department received a letter from the homeowner thanking us for the valiant effort displayed in saving her home . the act of kindness she noted above all others : someone had even gotten her a pair of shoes . ( laughter ) in both my vocation at robin hood and my avocation as a volunteer firefighter , i am witness to acts of generosity and kindness on a monumental scale , but i 'm also witness to acts of grace and courage on an individual basis . and you know what i 've learned ? they all matter . so as i look around this room at people who either have achieved , or are on their way to achieving , remarkable levels of success , i would offer this reminder : do n't wait . do n't wait until you make your first million to make a difference in somebody 's life . if you have something to give , give it now . serve food at a soup kitchen . clean up a neighborhood park . be a mentor . not every day is going to offer us a chance to save somebody 's life , but every day offers us an opportunity to affect one . so get in the game . save the shoes . thank you . ( applause ) bruno giussani : mark , mark , come back . ( applause ) mark bezos : thank you .
|
so , not exactly what i was hoping for , but off i went -- up the stairs , down the hall , past the 'real ' firefighters , who were pretty much done putting out the fire at this point , into the master bedroom to get a pair of shoes . now i know what you 're thinking , but i 'm no hero . ( laughter ) i carried my payload back downstairs where i met my nemesis and the precious dog by the front door .
|
what does it mean to be a hero ?
|
every spring , hundreds of adventure-seekers dream of climbing qomolangma , also known as mount everest . at base camp , they hunker down for months waiting for the chance to scale the mountain 's lofty , lethal peak . but why do people risk life and limb to climb everest ? is it the challenge ? the view ? the chance to touch the sky ? for many , the draw is everest 's status as the highest mountain on earth . there 's an important distinction to make here . mauna kea is actually the tallest from base to summit , but at 8850 meters above sea level , everest has the highest altitude on the planet . to understand how this towering formation was born , we have to peer deep into our planet 's crust , where continental plates collide . the earth 's surface is like an armadillo 's armor . pieces of crust constantly move over , under , and around each other . for such huge continental plates , the motion is relatively quick . they move two to four centimeters per year , about as fast as fingernails grow . when two plates collide , one pushes into or underneath the other , buckling at the margins , and causing what 's known as uplift to accomodate the extra crust . that 's how everest came about . 50 million years ago , the earth 's indian plate drifted north , bumped into the bigger eurasian plate , and the crust crumpled , creating huge uplift . mountain everest lies at the heart of this action , on the edge of the indian-eurasian collision zone . but mountains are shaped by forces other than uplift . as the land is pushed up , air masses are forced to rise as well . rising air cools , causing any water vapor within it to condense and form rain or snow . as that falls , it wears down the landscape , dissolving rocks or breaking them down in a process known as weathering . water moving downhill carries the weathered material and erodes the landscape , carving out deep valleys and jagged peaks . this balance between uplift and erosion gives a mountain its shape . but compare the celestial peaks of the himalayas to the comforting hills of appalachia . clearly , all mountains are not alike . that 's because time comes into the equation , too . when continental plates first collide , uplift happens fast . the peaks grow tall with steep slopes . over time , however , gravity and water wear them down . eventually , erosion overtakes uplift , wearing down peaks faster than they 're pushed up . a third factor shapes mountains : climate . in subzero temperatures , some snowfall does n't completely melt away , instead slowly compacting until it becomes ice . that forms the snowline , which occurs at different heights around the planet depending on climate . at the freezing poles , the snowline is at sea level . near the equator , you have to climb five kilometers before it gets cold enough for ice to form . gathered ice starts flowing under its own immense weight forming a slow-moving frozen river known as a glacier , which grinds the rocks below . the steeper the mountains , the faster ice flows , and the quicker it carves the underlying rock . glaciers can erode landscapes swifter than rain and rivers . where glaciers cling to mountain peaks , they sand them down so fast , they lop the tops off like giant snowy buzzsaws . so then , how did the icy mount everest come to be so tall ? the cataclysmic continental clash from which it arose made it huge to begin with . secondly , the mountain lies near the tropics , so the snowline is high , and the glaciers relatively small , barely big enough to widdle it down . the mountain exists in a perfect storm of conditions that maintain its impressive stature . but that wo n't always be the case . we live in a changing world where the continental plates , earth 's climate , and the planet 's erosive power might one day conspire to cut mount everest down to size . for now , at least , it remains legendary in the minds of hikers , adventurers , and dreamers alike .
|
water moving downhill carries the weathered material and erodes the landscape , carving out deep valleys and jagged peaks . this balance between uplift and erosion gives a mountain its shape . but compare the celestial peaks of the himalayas to the comforting hills of appalachia .
|
which factor ( s ) , along with time , affect the shape of a mountain ?
|
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 .
|
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 .
|
before moving onto writing numbers as products of 3 natural numbers , we should be confident writing them as products of 2 natural numbers . try writing the numbers 60 and 108 as all possible products of 2 natural numbers .
|
once upon a time , south america lived harmoniously alongside africa until a crack in the earth drove the two continents apart . this breakup began about 200 million years ago during the separation of the supercontinent known as pangaea . their proximity back then explains why the same plant fossils and reptile fossils , like the mesosaurus , can be found on the south american east coast and african west coast . however , this evidence does not account for how the continents moved apart . for that , we 'll need to take a close look at the earth below our feet . though you may not realize it , the ground below you is traveling across the earth at a rate of about 10 cm/year , or the speed at which your fingernails grow . this is due to plate tectonics , or the large-scale movement of earth 's continents . the motion occurs within the top two layers of the earth 's mantle , the lithosphere and asthenosphere . the lithosphere , which includes the crust and uppermost mantle , comprises the land around you . beneath the lithosphere is the asthenosphere the highly viscous but solid rock portion of the upper mantle . it 's between 80 and 200 km below the earth 's surface . while the asthenosphere wraps around the earth 's core as one connected region , the lithosphere is separated on top into tectonic plates . there are seven primary tectonic plates that compose the shape of the planet we know today . like the other smaller tectonic plates , the primary plates are about 100 km thick and are composed of one or two layers : continental crust and oceanic crust . continental crust forms the continents and areas of shallow water close to their shores , whereas oceanic crust forms the ocean basins . the transition from the granitic continental crust to the basaltic oceanic crust occurs beyond the continentel shelf , in which the shore suddenly slopes down towards the ocean floor . the south american plate is an example of a tectonic plate made of two crusts : the continent we know from today 's map and a large region of the atlantic ocean around it . collectively comprising the lithosphere , these plates are brittler and stiffer than the heated , malleable layer of the asthenosphere below . because of this , the tectonic plates float on top of this layer , independently of one another . the speed and direction in which these tectonic plates move depends on the temperature and pressure of the asthenosphere below . scientists are still trying to nail down the driving forces behind this movement , with some theories pointing towards mantle convection , while others are examining the influence of the earth 's rotation and gravitational pull . though the mechanics have not been sorted out , the scientific community agrees that our tectonic plates are moving and have been for billions of years . because these plates move independently , a fair amount of pushing and pulling between the plates occurs . the first type of interaction is a divergent boundary , in which two plates move away from one another . we see this in the mid-atlantic ridge between south america and africa . the next interaction is when two plates collide , known as a convergent boundary . in this instance , the land is pushed upward to form large mountain ranges , like the himalayas . in fact , the indian plate is still colliding with the eurasian plate , which is why mount everest grows one cm/year . finally , there 's the transform boundaries , where two plates scrape past one another . the grinding of the transform boundary leads to many earthquakes , which is what happens in the 810 mile-long san andreas fault . the moving earth is unstoppable , and , while a shift of 10 cm/year may not seem like a lot , over millions of years our planet will continue to dramatically change . mountains will rise , shorelines will recede , islands will pop up . in fact , one projected map shows the cities of los angeles and san francisco on top of each other . maybe south america and africa will come together again , too . only time will tell .
|
once upon a time , south america lived harmoniously alongside africa until a crack in the earth drove the two continents apart . this breakup began about 200 million years ago during the separation of the supercontinent known as pangaea . their proximity back then explains why the same plant fossils and reptile fossils , like the mesosaurus , can be found on the south american east coast and african west coast .
|
what was the name of the supercontinent that existed about 300 million years ago ?
|
in 1962 , a cave explorer named michel siffre started a series of experiments where he isolated himself underground for months without light or clocks . he attached himself to electrodes that monitored his vital signs and kept track of when he slept and ate . when siffre finally emerged , the results of his pioneering experiments revealed that his body had kept to a regular sleeping-waking cycle . despite having no external cues , he fell asleep , woke up , and ate at fixed intervals . this became known as a circadian rhythm from the latin for `` about a day . '' scientists later found these rhythms affect our hormone secretion , how our bodies process food , and even the effects of drugs on our bodies . the field of sciences studying these changes is called chronobiology . being able to sense time helps us do everything from waking and sleeping to knowing precisely when to catch a ball that 's hurtling towards us . we owe all these abilities to an interconnected system of timekeepers in our brains . it contains the equivalent of a stopwatch telling us how many seconds elapsed , a clock counting the hours of the day , and a calendar notifying us of the seasons . each one is located in a different brain region . siffre , stuck in his dark cave , relied on the most primitive clock in the suprachiasmatic nucleus , or scn of the hypothalamus . here 's the basics of how we think it works based on fruitfly and mouse studies . proteins known as clk , or clock , accumulate in the scn throughout the day . in addition to activating genes that tell us to stay awake , they make another protein called per . when enough per accumulates , it deactivates the gene that makes clk , eventually making us fall asleep . then , clock falls low , so per concentrations also drop again , allowing clk to rise , starting the cycle over . there are other proteins involved , but our day and night cycle may be driven in part by this seesaw effect between clk by day and per by night . for more precision , our scns also rely on external cues like light , food , noise , and temperature . we called these zeitgebers , german for `` givers of time . '' siffre lacked many of these cues underground , but in normal life , they fine tune our daily behavior . for instance , as natural morning light filters into our eyes , it helps wake us up . traveling through the optic nerve to the scn , it communicates what 's happening in the outside world . the hypothalamus then halts the production of melatonin , a hormone that triggers sleep . at the same time , it increases the production of vasopressin and noradrenaline throughout the brain , which help control our sleep cycles . at about 10 am , the body 's rising temperature drives up our energy and alertness , and later in the afternoon , it also improves our muscle activity and coordination . bright screens at night can confuse these signals , which is why binging on tv before bed makes it harder to sleep . but sometimes we need to be even more precise when telling the time , which is where the brain 's internal stopwatch chimes in . one theory for how this works involves the fact that communication between a given pair of neurons always takes roughly the same amount of time . so neurons in our cortex and other brain areas may communicate in scheduled , predictable loops that the cortex uses to judge with precision how much time has passed . that creates our perception of time . in his cave , siffre made a fascinating additional discovery about this . every day , he challenged himself to count up to 120 at the rate of one digit per second . over time , instead of taking two minutes , it began taking him as long as five . life in the lonely , dark cave had warped siffre 's own perception of time despite his brain 's best efforts to keep him on track . this makes us wonder what else influences our sense of time . and if time is n't objective , what does that mean ? could each of us be experiencing it differently ? only time will tell .
|
there are other proteins involved , but our day and night cycle may be driven in part by this seesaw effect between clk by day and per by night . for more precision , our scns also rely on external cues like light , food , noise , and temperature . we called these zeitgebers , german for `` givers of time . ''
|
to increase precision , our brain takes cues from the outside world such as :
|
most atoms do n't ride solo , instead they bond with other atoms . and bonds can form between atoms of the same element or atoms of different elements . you 've probably imagined bonding as a tug of war . if one atom is really strong , it can pull one or more electrons off another atom . then you end up with one negatively charged ion and one positively charged ion . and the attraction between these opposite charges is called an ionic bond . this is the kind of sharing where you just give away your toy to someone else and then never get it back . table salt , sodium chloride , is held together by ionic bonds . every atom of sodium gives up one electron to every atom of chlorine , ions are formed , and those ions arrange themselves in a 3d grid called a lattice , in which every sodium ion is bonded to six chloride ions , and every chloride ion is bonded to six sodium ions . the chlorine atoms never give the sodium atoms their electrons back . now , these transactions are n't always so cut-and-dried . if one atom does n't completely overwhelm the other , they can actually share each other 's electrons . this is like a pot luck where you and a friend each bring a dish and then both of you share both dishes . each atom is attracted to the shared electrons in between them , and this attraction is called a covalent bond . the proteins and dna in our bodies , for example , are held together largely by these covalent bonds . some atoms can covalently bond with just one other atom , others with many more . the number of other atoms one atom can bond with depends on how its electrons are arranged . so , how are electrons arranged ? every atom of a pure , unbonded element is electrically neutral because it contains the same number of protons in the nucleus as it does electrons around the nucleus . and not all of those electrons are available for bonding . only the outermost electrons , the ones in orbitals furthest from the nucleus , the ones with the most energy , only those participate in bonding . by the way , this applies to ionic bonding too . remember sodium chloride ? well , the electron that sodium loses is the one furthest from its nucleus , and the orbital that electron occupies when it goes over to chlorine is also the one furthest from its nucleus . but back to covalent bonding . carbon has four electrons that are free to bond , nitrogen has three , oxygen two . so , carbon is likely to form four bonds , nitrogen three , and oxygen two . hydrogen only has one electron , so it can only form one bond . in some special cases , atoms can form more bonds than you 'd expect , but they better have a really good reason to do so , or things tend to fly apart . groups of atoms that share electrons covalently with each other are called molecules . they can be small . for example , every molecule of oxygen gas is made up of just two oxygen atoms bonded to each other . or they could be really , really big . human chromosome 13 is just two molecules , but each one has over 37 billion atoms . and this neighborhood , this city of atoms , is held together by the humble chemical bond .
|
well , the electron that sodium loses is the one furthest from its nucleus , and the orbital that electron occupies when it goes over to chlorine is also the one furthest from its nucleus . but back to covalent bonding . carbon has four electrons that are free to bond , nitrogen has three , oxygen two .
|
in a covalent bond , ________ .
|
imagine , for a second , a duck teaching a french class , a ping-pong match in orbit around a black hole , a dolphin balancing a pineapple . you probably have n't actually seen any of these things , but you could imagine them instantly . how does your brain produce an image of something you 've never seen ? that may not seem hard , but that 's only because we 're so used to doing it . it turns out that this is actually a complex problem that requires sophisticated coordination inside your brain . that 's because to create these new , weird images , your brain takes familiar pieces and assembles them in new ways , like a collage made from fragments of photos . the brain has to juggle a sea of thousands of electrical signals getting them all to their destination at precisely the right time . when you look at an object , thousands of neurons in your posterior cortex fire . these neurons encode various characteristics of the object : spiky , fruit , brown , green , and yellow . this synchronous firing strengthens the connections between that set of neurons , linking them together into what 's known as a neuronal ensemble , in this case the one for pineapple . in neuroscience , this is called the hebbian principle , neurons that fire together wire together . if you try to imagine a pineapple later , the whole ensemble will light up , assembling a complete mental image . dolphins are encoded by a different neuronal ensemble . in fact , every object that you 've seen is encoded by a neuronal ensemble associated with it , the neurons wired together by that synchronized firing . but this principle does n't explain the infinite number of objects that we can conjure up in our imaginations without ever seeing them . the neuronal ensemble for a dolphin balancing a pineapple does n't exist . so how come you can imagine it anyway ? one hypothesis , called the mental synthesis theory , says that , again , timing is key . if the neuronal ensembles for the dolphin and pineapple are activated at the same time , we can perceive the two separate objects as a single image . but something in your brain has to coordinate that firing . one plausible candidate is the prefrontal cortex , which is involved in all complex cognitive functions . prefrontal cortex neurons are connected to the posterior cortex by long , spindly cell extensions called neural fibers . the mental synthesis theory proposes that like a puppeteer pulling the strings , the prefrontal cortex neurons send electrical signals down these neural fibers to multiple ensembles in the posterior cortex . this activates them in unison . if the neuronal ensembles are turned on at the same time , you experience the composite image just as if you 'd actually seen it . this conscious purposeful synchronization of different neuronal ensembles by the prefrontal cortex is called mental synthesis . in order for mental sythesis to work , signals would have to arrive at both neuronal ensembles at the same time . the problem is that some neurons are much farther away from the prefrontal cortex than others . if the signals travel down both fibers at the same rate , they 'd arrive out of sync . you ca n't change the length of the connections , but your brain , especially as it develops in childhood , does have a way to change the conduction velocity . neural fibers are wrapped in a fatty substance called myelin . myelin is an insulator and speeds up the electrical signals zipping down the nerve fiber . some neural fibers have as many as 100 layers of myelin . others only have a few . and fibers with thicker layers of myelin can conduct signals 100 times faster or more than those with thinner ones . some scientists now think that this difference in myelination could be the key to uniform conduction time in the brain , and consequently , to our mental synthesis ability . a lot of this myelination happens in childhood , so from an early age , our vibrant imaginations may have a lot to do with building up brains whose carefully myelinated connections can craft creative symphonies throughout our lives .
|
if the neuronal ensembles for the dolphin and pineapple are activated at the same time , we can perceive the two separate objects as a single image . but something in your brain has to coordinate that firing . one plausible candidate is the prefrontal cortex , which is involved in all complex cognitive functions .
|
you want to forget your ex . is it possible for a doctor ( theoretically speaking ) to rid your brain from the memory of your ex ?
|
twenty-one grams . that is the mass of all of the electrons in your body if , like me , you weigh about 70 kilograms . now all of the mass comes from the higgs mechanism , which means that as your electrons are traveling through space time , they interact with the higgs field and it is that that gives them their mass . it slows them down and stops them from traveling at the speed of light . but most of your mass doesn ’ t come from the higgs mechanism . and neither does all of this stuff that you see around you . the mass is coming from somewhere quite different and that is because most of your mass and most of this mass comes from neutrons and protons and they are not fundamental particles . they are made of constituent particles called quarks . now the theory that describes quarks and their interactions with each other through gluons is called quantum chromo dynamics . and chromo is the greek word for color . so in some way these objects are meant to carry the color charge . but they are much , much smaller than the wavelength of visible light , so there is no way that they are actually colored , but it is a useful analogy that helps us think about how they interact and the particles that they can make up . now the rules are pretty simple . in order for a particle to exist , it must be colorless or white , like this house . now you can accomplish that in two different ways . you could make three quarks in where each one is a different color , red , green and blue , so overall they combine to produce white . or you could use a quark and an anti quark where one is a color like green and the other is its anti color , say , magenta . now what i would like to do on this little patch of beach behind me is simulate how quarks actually bind together and form different particles . now for this you need to remember that in the last video we talked about how empty space is not truly empty . so the beach here is has these undulations in it which represent the fluctuations in the gluon field . but you have to imagine this beach sort of rippling and these bumps coming and going . now that is really important , because to get rid of those fluctuations actually takes energy . and this is an important part of binding the quarks together . the existence of quarks actually suppresses the gluon fluctuations and creates what is called a flux tube , an area where there is really nothing in the vacuum and that is in between this quark and the anti quark . and that pairs them up and creates what is called a meson , the quark , anti quark pair . what is interesting about that flux tube is that as these quarks become more separated , the flux tube remains the same diameter and the same sort of depth of suppression of the field , which means that the force does n't actually increase . it is not like a spring . it is not like an elastic band . the force is the same that is pulling these quarks back together . but you are putting more work in as you move these quarks and anti quarks further apart . and so for a time people thought : well , these quarks are always going t be confined , however far you move them . you are just going to get a really long flux tube . but what actually happens is you that you put in enough energy that you can actually create a quark , anti quark pair . > > nevertheless , the quarks are still combined . you can never see an individual quark , because if you try to pull it out , you put so much energy into the situation that another quark , anti quark pair will be created . > > now to form a proton , we are going to need an up quark , another up quark and a down quark . now the standard model of a proton that you have probably seen involves these quarks bounded together by little gluon springs that go between them . > > we know that that picture is totally wrong now . even in the best sense you might have hoped that you would see flux tubes around the edge of the triangle . but we know that , in fact , they don ’ t do that . that you get these y shaped flex tubes . > > the crazy thing about a proton is that there may be more than three quarks there . you see , you can have additional quark , anti quark pairs pop in and out of existence . so at any given time there could be five or seven or nine , any odd number of quarks could make up a proton . so this is what a proton actually looks like . you can see that the quarks like to sit on those lumps in the gluon field . and you can see the two up quarks and a down quark , but there is also a strange quark and an anti strange quark , which is strange , because you don ’ t normally think of these quarks being inside a proton , but they can be at any particular point in time . and you can also see that these quarks have cleared out the vacuum . and you can see that there is kind of these flux tubes which are the areas where the gluon field has been suppressed . and that is really what is binding these quarks together . > > that is the strong force that binds quarks into the heart of the proton . > > it is intrinsically related to the fact that clearing out those fluctuations has more energy than where they are . > > that is right . it costs energy to clear the vacuum . > > so where is the mass of the proton really coming from ? well , of course , the constituent quarks do interact with the higgs field and that gives them a small amount of mass . but if you add up the mass of all the quarks in the proton it would only account for about one percent of its total mass . so where is the rest of the mass coming from ? the answer is : energy . you know , einstein ’ s famous equation : e equals mc squared . well , that says we have got a lot of energy for just a little bit of a mass . but if you rearrange the equation you can see that we can get an amount of mass if there is lots of energy there . and that is really where most of the mass of the proton is coming from . it is from the fact that there are these energy fluctuations in the gluon field and the quarks are interacting with those gluons . that is where your mass is coming from . it is coming from the energy that is in there . you know , einstein talked about , well , if i had a hot cup of tea , it would actually have a slightly greater mass than the same cup of tea when cold . and he was right . i mean , you can ’ t measure it with a cup of tea , but most of your mass you owe to e equals mc squared , you owe to the fact that your mass is packed with energy , because of the interactions between the quarks and these gluon fluctuations in that gluon field . i think it is extraordinary , because what we think of as ordinarily empty space , you know , that turns out to be the thing that gives us all most of our mass . i really want to thank audible.com for supporting this episode of veritasium . in case you don ’ t know , audble.com is a leading provider of audio books with over 100,000 titles in all areas of literature including fiction , non fiction and periodicals . you know , one of my favorite books is by james gleick . it is called the information : a history , a theory , a flood . and if you head on over to audible.com/veritasium you can download it right now for free . or you could pick another book of your choosing . you know , it is great to have support from people like audible , because that allows me to keep this content for you for free . so please go check it out .
|
and he was right . i mean , you can ’ t measure it with a cup of tea , but most of your mass you owe to e equals mc squared , you owe to the fact that your mass is packed with energy , because of the interactions between the quarks and these gluon fluctuations in that gluon field . i think it is extraordinary , because what we think of as ordinarily empty space , you know , that turns out to be the thing that gives us all most of our mass . i really want to thank audible.com for supporting this episode of veritasium .
|
the interactions that our quarks ( that make up our protons and neutrons ) have with the gluon field is responsible for most of our mass . why does our video host think this is extraordinary ? ( video hint:6:02 )
|
( music ) sometimes when i 'm on a long plane flight , i gaze out at all those mountains and deserts and try to get my head around how vast our earth is . and then i remember that there 's an object we see every day that would literally fit one million earths inside it . the sun seems impossibly big , but in the great scheme of things , it 's a pinprick , one of about 400 billion stars in the milky way galaxy , which you can see on a clear night as a pale , white mist stretched across the sky . and it gets worse . there are maybe 100 billion galaxies detectable by our telescopes , so if each star was the size of a single grain of sand , just the milky way has enough stars to fill a 30 foot by 30 foot stretch of beach three feet deep with sand . and the entire earth does n't have enough beaches to represent the stars in the overall universe . such a beach would continue for literally hundreds of millions of miles . holy stephen hawking , that is a lot of stars . but he and other physicists now believe in a reality that is unimaginably bigger still . i mean , first of all , the 100 billion galaxies within range of our telescopes are probably a minuscule fraction of the total . space itself is expanding at an accelerating pace . the vast majority of the galaxies are separating from us so fast that light from them may never reach us . still , our physical reality here on earth is intimately connected to those distant , invisible galaxies . we can think of them as part of our universe . they make up a single , giant edifice , obeying the same physical laws and all made from the same types of atoms , electrons , protons , quarks , neutrinos that make up you and me . however , recent theories in physics , including one called string theory , are now telling us there could be countless other universes , built on different types of particles , with different properties , obeying different laws . most of these universes could never support life , and might flash in and out of existence in a nanosecond , but nonetheless , combined they make up a vast multiverse of possible universes . in up to 11 dimensions , featuring wonders beyond our wildest imagination . and the leading version of string theory predicts a multiverse made of up to 10 to the 500 universes . that 's a one followed by 500 zeroes , a number so vast that if every atom in our observable universe had its own universe and all of the atoms in all of those universes each had their own universe , and you repeated that for two more cycles , you 'd still be at a tiny fraction of the total -- namely , one trillion trillion trillion trillion trillion trillion trillion trillion trillion trillion trillion trillion trillion trillion trillionth . but even that number is minuscule compared to another number : infinity . some physicists think the space-time continuum is literally infinite , and that it contains an infinite number of so-called pocket universes with varying properties . how 's your brain doing ? but quantum theory adds a whole new wrinkle . i mean , the theory 's been proven true beyond all doubt , but interpreting it is baffling . and some physicists think you can only un-baffle it if you imagine that huge numbers of parallel universes are being spawned every moment , and many of these universes would actually be very like the world we 're in , would include multiple copies of you . in one such universe , you 'd graduate with honors and marry the person of your dreams . in another , not so much . there are still some scientists who would say , hogwash . the only meaningful answer to the question of how many universes there are is one , only one universe . and a few philosophers and mystics might argue that even our own universe is an illusion . so , as you can see , right now there is no agreement on this question , not even close . all we know is , the answer is somewhere between zero and infinity . well , i guess we know one other thing : this is a pretty cool time to be studying physics . we just might be undergoing the biggest paradigm shift in knowledge that humanity has ever seen .
|
( music ) sometimes when i 'm on a long plane flight , i gaze out at all those mountains and deserts and try to get my head around how vast our earth is . and then i remember that there 's an object we see every day that would literally fit one million earths inside it . the sun seems impossibly big , but in the great scheme of things , it 's a pinprick , one of about 400 billion stars in the milky way galaxy , which you can see on a clear night as a pale , white mist stretched across the sky .
|
approximately how many planet earths could you fit inside the sun ?
|
i ’ ve invited you all here today because i wanted to talk to you about some ugly stereotypes that are going around . i ’ ve been hearing a lot of unfair , unseemly , and unscientific generalizations being made lately . and they mostly have to do with sex . and your hormones . people have a nasty habit of equating “ hormones ” with a particular set of behaviors and conditions , most of which have to do with reproduction , or sexual development , or acts that include what my brother john has referred to as “ skoodilypooping. ” for example , people will say that “ hormones ” are why kevin has zits , and is being all moody , or why hannah , who ’ s three months pregnant , just cried watching a commercial for car insurance -- which , let ’ s be honest , i do that too . now , i ’ m not saying that hormones aren ’ t at the root of sexual attraction , or zits , or occasional bouts of extreme emotion , because they are . that ’ s just not all that they do . not even close . when people talk about “ hormones ” in the contexts that i just mentioned , what really they mean is `` sex hormones . '' but sex hormones are just one kind of hormone that you have coursing through your body right now . in fact , there are at least 50 different types of these chemical messengers at work in your body at this very minute , but only a very few of them have anything at all to do with sex . the truth is , from birth to death , just about every cell and function in your body is under your hormones ’ constant influence . they ’ re floating through your blood , regulating your metabolism , your sleep cycle , your response to stress , and the general and incredibly important overall homeostasis that keeps you not dead . some hormones are just there to make other hormones trigger even more hormones -- in a kind of chemical relay race that biologists refer to , rather elegantly , as “ cascades. ” these hormones run through you no matter what your mood is , or whether you have zits . so the reality is : we ’ re all hormonal ... all of the time . ok , to begin to understand our hormones -- and the endocrine system that produces , releases , and re-absorbs them -- we have to step back and take a broad view . not just by emphasizing that sex hormones aren ’ t the only hormones you have -- but also by looking at how your hormones interact with your other organ systems . because , if anything , your body has two bosses -- two complementary systems that are constantly shouting instructions over each other , to all of your bits and pieces . both your endocrine system and your nervous system are constantly trafficking information around your corpus , gathering intel , making demands , controlling your every move . they just have totally different ways of doing it . your nervous system uses lightning-fast electrochemical action potentials , delivered by an expressway made of neurons to specific cells and organs . but your endocrine system prefers a slower , wider stream of data . it secretes hormones that travel through your blood -- not through neurons -- so they move more slowly , but they also produce widespread effects that last a whole lot longer than an action potential . now , compared to your heart or brain or other , arguably more glamorous organs , your endocrine system ’ s organs and glands are kinda small and lumpy . they ’ re also rogues -- instead of being all nestled together like in your other organ systems , these guys are scattered all over the place , from your brain to your throat , to your kidneys , to your genitals . a gland is a just any structure that makes and secretes a hormone . and the master gland in your body is the pituitary , which produces many hormones that signal other glands -- like the thyroid , parathyroid , adrenal , and pineal glands -- to make their own hormones . the endocrine system also includes a few organs -- like the gonads , the pancreas , and the placenta in pregnant women -- all of which have some other non-hormonal functions and are made up of multiple tissue types . and technically the hypothalamus in your brain is in the endocrine club too , since in addition to all of its busy brain duties , it does produce and release hormones . so , thanks to these glands and organs , you ’ ve got all these hormones diffusing through your blood , doing all sorts of different things , but the thing to remember about them is that a hormone can only trigger a reaction in specific cells -- their so-called target cells -- that have the right receptors for it . so , just like some keys can open many locks , while others only work with one , so too can the hormone-target-cell relationship either be widespread or localized . you ’ re probably gon na want an example of that . so , your thyroid -- at the bottom of your throat -- produces the hormone thyroxine , which stimulates metabolism and binds to receptors in most of the cells in your body . but your pituitary -- which is nestled all comfy under your brain -- produces follicle-stimulating hormone , which helps regulate growth and triggers sexual maturity , and it only targets specific cells in the ovaries and testes . so how do hormones bind to their target cells ? well , chemically , most hormones are either made of amino acids -- including their more complex structures like peptides or proteins -- or they ’ re derived from lipids , like cholesterol . and this is key , because a hormone ’ s chemical structure determines if it ’ s water soluble , like most amino acid-based ones are , or lipid soluble , like steroids are . solubility is important because your cell membranes are made of lipids . that means that water soluble ones can ’ t get across them . so target cells for those kinds of hormones have receptors for them on the outside of their membranes . lipid-soluble hormones , on the other hand , can just basically glide right through that cell membrane , so their receptor sites are inside their target cells . either way , when a target cell is activated , the hormone alters its activity , by either increasing or decreasing some of its functions -- usually with the goal of maintaining your body ’ s homeostasis in one way or another . so , if hormones are keeping your body in balance , what ’ s putting your body out of balance ? i don ’ t know -- could i interest you in some pie ? if you have a couple of nice , generous helpings of strawberry-rhubarb pie -- and just to make things interesting , let ’ s say they ’ re a la mode -- your blood glucose level is gon na go through the roof . and the pancreas regulates your blood sugar by releasing two different hormones -- insulin and glucagon . once you have a belly full of that pie , beta cells in your pancreas release insulin , which helps lower your blood sugar by increasing the rate at which your cells store the sugar either as glycogen or as fat for later use . now , let ’ s say you ’ ve done the opposite : you ’ ve eaten no pie -- you ’ re pie-less -- in fact , you ’ ve eaten nothing for hours . if your blood sugar drops too low , then alpha cells in the pancreas will instead send out glucagon , which helps raise your blood sugar levels , in part by decreasing the storage of sugar in your cells , and triggering their release of glucose back into the blood . lots of different endocrine-related illnesses -- like diabetes or hyperthyroidism -- tend to be the result of either hyper ( too much ) or hypo ( too little ) secretion of certain hormones , which throw your homeostasis off balance . but there are lots of more common -- and less obvious -- ways your hormones can get out of balance , not because of some disorder , but because these signaling chemicals are just caught up in a chain reaction , which can take a while to subside . some hormones just exist to control other hormones , which in turn control still more hormones . so as soon as one starts to trickle out , you can pretty quickly wind up with a cascade on your hands . you ’ ve got a few different hormone cascades going on at any given moment , but one of the big ones -- one that ’ s really worth understanding -- is the hypothalamic-pituitary-adrenal axis , or the hpa axis , because you don ’ t want to have to say that every time . this is a complex series of interactions between three glands that ultimately regulates lots of your body ’ s daily processes , like digestion , sexuality , immune response , and how you handle stress . and it ’ s complex not just because of all the glands involved -- it ’ s also one of the more crucial instances of your endocrine system coordinating with your nervous system . specifically , it ’ s behind that fight-or-flight response that everybody keeps talking about . the hpa axis is essentially the endocrine system ’ s companion to the sympathetic nervous system . the sympathetic system , in times of high stress , does things like speed up your heart rate and direct blood away from the digestive organs and to the muscles . but many of the other effects of the stress response are carried out by your endocrine system . and getting your nervous and endocrine systems to work together in times of crisis is where the hypothalamus comes in . it ’ s the hub of where the two systems meet -- it keeps tabs on what ’ s going on all over your body , analyzing your blood for signs that something might be off . so , let ’ s revisit our fight-or-flight scene from a few lessons ago -- the old burning house scenario . so you ’ re sleeping , dreaming about petting pandas with emma watson or whatever , when the smoke alarm goes off . well , action potentials in your brain trigger neurons in your hypothalamus to release the peptide hormone crh , or corticotropin releasing hormone . the crh makes the very short trip through the bloodstream to the anterior pituitary gland , where , because it ’ s water soluble , it binds to receptors on the outside of its target cells . there , it triggers the release of adrenocorticotropic hormone , or acth . the acth travels -- again through the bloodstream -- to the adrenal cortices of the adrenal glands on top of your kidneys . when the acth binds to receptors on cells in an adrenal cortex , it triggers the release of a frenzy of different freak-out compounds known as glucocorticoid and mineralcorticoid hormones . typically these guys help us deal with day-to-day stress by keeping our blood sugar and blood pressure balanced . but under major stress -- like waking up in a burning building stress -- these hormones , like cortisol , cause the classic fight-or-flight response : ramping up your blood pressure , dumping glucose into your bloodstream , shutting down non-emergency services like your immune system and sperm and egg development . and guess what ? now that all these stress hormones are pulsing through your blood , the hypothalamus back in the brain senses them . and because its job is to monitor and maintain balance whenever possible , it then stops secreting crh , which -- eventually -- causes the other glands to stop secreting their panic hormones . now , because this element of the stress response is hormonal rather than electrical , it comes on more slowly than the nervous system part , and it takes longer to subside , too , as those stress hormones linger in the blood before being broken down by enzymes . so . we ’ re a long way from teenage crushes and zits and crying over commercials at this point , aren ’ t we ? as a life-long owner of hormones , i hope you ’ ll join me in dispelling the stereotypes that surround these powerful and important chemicals , and give them the respect they rightly deserve . today we looked at the endocrine system , and how it uses glands to produce hormones . these hormones are either amino-acid based and water soluble , or steroidal and lipid-soluble , and may target many types of cells or just turn on specific ones . we also touched on hormone cascades , and how the hpa axis effects your stress response . thank you to our headmaster of learning , thomas frank , and to all of our patreon patrons who help make crash course possible through their monthly contributions . if you like crash course and you want to help us keep making free educational content for the whole world , you can go to patreon.com/crashcourse . crash course is filmed in the doctor cheryl c. kinney crash course studio . this episode was written by kathleen yale , edited by blake de pastino , and our consultant is dr. brandon jackson . it was directed by nicholas jenkins , the editor is nicole sweeney , the script supervisor was stefan chin , our sound designer is michael aranda and the graphics team is thought café .
|
but there are lots of more common -- and less obvious -- ways your hormones can get out of balance , not because of some disorder , but because these signaling chemicals are just caught up in a chain reaction , which can take a while to subside . some hormones just exist to control other hormones , which in turn control still more hormones . so as soon as one starts to trickle out , you can pretty quickly wind up with a cascade on your hands .
|
hormones control and regulate which of these functions ?
|
before the creation of humanity , the greek gods won a great battle against a race of giants called the titans . most titans were destroyed or driven to the eternal hell of tartarus . but the titan prometheus , whose name means foresight , persuaded his brother epimetheus to fight with him on the side of the gods . as thanks , zeus entrusted the brothers with the task of creating all living things . epimetheus was to distribute the gifts of the gods among the creatures . to some , he gave flight ; to others , the ability to move through water or race through grass . he gave the beasts glittering scales , soft fur , and sharp claws . meanwhile , prometheus shaped the first humans out of mud . he formed them in the image of the gods , but zeus decreed they were too remain mortal and worship the inhabitants of mount olympus from below . zeus deemed humans subservient creatures vulnerable to the elements and dependent on the gods for protection . however , prometheus envisioned his crude creations with a greater purpose . so when zeus asked him to decide how sacrifices would be made , the wily prometheus planned a trick that would give humans some advantage . he killed a bull and divided it into two parts to present to zeus . on one side , he concealed the succulent flesh and skin under the unappealing belly of the animal . on the other , he hid the bones under a thick layer of fat . when zeus chose the seemingly best portion for himself , he was outraged at prometheus 's deception . fuming , zeus forbade the use of fire on earth , whether to cook meat or for any other purpose . but prometheus refused to see his creations denied this resource . and so , he scaled mount olympus to steal fire from the workshop of hephaestus and athena . he hid the flames in a hollow fennel stalk and brought it safely down to the people . this gave them the power to harness nature for their own benefit and ultimately dominate the natural order . with fire , humans could care for themselves with food and warmth . but they could also forge weapons and wage war . prometheus 's flames acted as a catalyst for the rapid progression of civilization . when zeus looked down at this scene , he realized what had happened . prometheus had once again wounded his pride and subverted his authority . furious , zeus imposed a brutal punishment . prometheus was to be chained to a cliff for eternity . each day , he would be visited by a vulture who would tear out his liver and each night his liver would grow back to be attacked again in the morning . although prometheus remained in perpetual agony , he never expressed regret at his act of rebellion . his resilience in the face of oppression made him a beloved figure in mythology . he was also celebrated for his mischievous and inquisitive spirit , and for the knowledge , progress , and power he brought to human hands . he 's also a recurring figure in art and literature . in percy bysshe shelley 's lyrical drama `` prometheus unbound , '' the author imagines prometheus as a romantic hero who escapes and continues to spread empathy and knowledge . of his protagonist , shelley wrote , `` prometheus is the type of the highest perfection of moral and intellectual nature , impelled by the purest and the truest motives to the best and noblest ends . '' his wife mary envisaged prometheus as a more cautionary figure and subtitled her novel `` frankenstein : the modern prometheus . '' this suggests the damage of corrupting the natural order and remains relevant to the ethical questions surrounding science and technology today . as hero , rebel , or trickster , prometheus remains a symbol of our capacity to capture the powers of nature , and ultimately , he reminds us of the potential of individual acts to ignite the world .
|
before the creation of humanity , the greek gods won a great battle against a race of giants called the titans . most titans were destroyed or driven to the eternal hell of tartarus . but the titan prometheus , whose name means foresight , persuaded his brother epimetheus to fight with him on the side of the gods .
|
the titans were :
|
which is correct : `` a dozen eggs is ? '' or `` a dozen eggs are ? '' i remember being in elementary school , and my teachers making a big deal about the unit . and i never really got that , until one day , i was in the grocery store , and i wanted to buy an apple , but i could n't buy one apple . i had to buy a whole bag of apples . so i did . i bought one bag of apples , i took it home , i took one apple out of the bag , and i cut it up . and then i ate one slice . one bag , one apple , one slice . which of these is the real `` one '' ? well , they all are of course , and that 's what my elementary teachers were trying to tell me . because this is the important idea behind whole number place value , decimal place value and fractions . our whole number system depends on being able to change what we count as `` one '' . our whole number system depends on being able to change units . there are two ways to change units . we can compose , and we can partition . when we compose units , we take a bunch of things , we put them together to make a bigger thing , like a dozen eggs . we take 12 eggs , put them together to make a group , and we call that group a dozen . a dozen eggs is a composed unit . other examples of composed units include a deck of cards , a pair of shoes , a jazz quartet and of course , barbie and ken make a couple . but think about a loaf of bread . that 's not a composed unit , because we do n't get a bunch of slices from a bunch of different bakeries and put them together to make a loaf . no , we start with a loaf of bread and we cut it into smaller pieces called slices , so each slice of bread is a partitioned unit . other examples of partitioned units include a square of a chocolate bar , a section of an orange and a slice of pizza . the important thing about units is that once we 've made a new unit , we can treat it just like we did the old unit . we can compose composed units , and we can partition partitioned units . think about toaster pastries . they come in packs of two , and then those packs get put together in sets of four to make a box . so when i buy one box of toaster pastries , am i buying one thing , four things , or eight things ? it depends on the unit . one box , four packs , eight pastries . and when i share a slice of pizza with a friend , we have to cut `` it '' into two smaller pieces . so a box of toaster pastries is composed of composed units , and when i split a slice of pizza , i 'm partitioning a partitioned unit . but what does that have to do with math ? in math , everything is certain . two plus two equals four , and one is just one . but that 's not really right . one is n't always one . here 's why : we start counting at one , and we count up to nine : 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , and then we get to 10 , and in order to write 10 , we write a one and a zero . that one means that we have one group , and the zero helps us remember that it means one group , not one thing . but 10 , just like one , just like a dozen eggs , just like an egg , 10 is a unit . and 10 tens make 100 . so when i think about 100 , it 's like the box of toaster pastries . is 100 one thing , 10 things or 100 things ? and that depends on what `` one '' is , it depends on what the unit is . so think about all the times in math when you write the number one . no matter what place that one is in , no matter how many things that one represents , one is .
|
here 's why : we start counting at one , and we count up to nine : 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , and then we get to 10 , and in order to write 10 , we write a one and a zero . that one means that we have one group , and the zero helps us remember that it means one group , not one thing . but 10 , just like one , just like a dozen eggs , just like an egg , 10 is a unit .
|
our number system is called a place value system because the value of a digit depends on its place in the number . the speaker in the video used the example of 1 ; sometimes it means one thing , sometimes it means one group of things , etc . in roman numerals , there is a separate symbol for ten . i means one , but x means ten . you may know that xi means eleven , while ix means 9. should we call roman numerals a place value system ? discuss .
|
in 1895 , a physicist named wilhelm roentgen was doing experiments with a cathode tube , a glass container in which a beam of electrons lights up a fluorescent window . he had wrapped cardboard around the tube to keep the fluorescent light from escaping , when something peculiar happened . another screen outside the tube was glowing . in other words , invisible rays had passed through the cardboard . wilhelm had no idea what those rays were , so he called them x-rays , and his discovery eventually won him a nobel prize . here 's what we now know was happening . when high energy electrons in the cathode tube hit a metal component , they either got slowed down and released extra energy , or kicked off electrons from the atoms they hit , which triggered a reshuffling that again released energy . in both cases , the energy was emitted in the form of x-rays , which is a type of electromagnetic radiation with higher energy than visible light , and lower energy than gamma rays . x-rays are powerful enough to fly through many kinds of matter as if they are semi-transparent , and they 're particularly useful for medical applications because they can make images of organs , like bones , without harming them , although they do have a small chance of causing mutations in reproductive organs , and tissues like the thyroid , which is why lead aprons are often used to block them . when x-rays interact with matter , they collide with electrons . sometimes , the x-ray transfers all of its energy to the matter and gets absorbed . other times , it only transfers some of its energy , and the rest is scattered . the frequency of these outcomes depends on how many electrons the x-rays are likely to hit . collisions are more likely if a material is dense , or if it 's made of elements with higher atomic numbers , which means more electrons . bones are dense and full of calcium , which has a relatively high atomic number , so they absorb x-rays pretty well . soft tissue , on the other hand , is n't as dense , and contains mostly lower atomic number elements , like carbon , hydrogen , and oxygen . so more of the x-rays penetrate tissues like lungs and muscles , darkening the film . these 2-d pictures are only useful up to a point , though . when x-rays travel through the body , they can interact with many atoms along the path . what is recorded on the film reflects the sum of all those interactions . it 's like trying to print 100 pages of a novel on a single sheet of paper . to see what 's really going on , you would have to take x-ray views from many angles around the body and use them to construct an internal image . and that 's something doctors do all the time in a procedure called a ct , computed tomography scan , another nobel prize winning invention . think of ct like this . with just one x-ray , you might be able to see the density change due to a solid tumor in a patient , but you would n't know how deep it is beneath the surface . however , if you take x-rays from multiple angles , you should be able to find the tumor 's position and shape . a ct scanner works by sending a fan or cone of x-rays through a patient to an array of detectors . the x-ray beam is rotated around the patient , and often also moved down the patient 's body , with the x-ray source tracing a spiral trajectory . spiral ct scans produce data that can be processed into cross sections detailed enough to spot anatomical features , tumors , blood clots , and infections . ct scans can even detect heart disease and cavities in mummies buried thousands of years ago . so what began as roentgen 's happy accident has become a medical marvel . hospitals and clinics now conduct over 100 millions scans each year worldwide to treat diseases and save lives .
|
however , if you take x-rays from multiple angles , you should be able to find the tumor 's position and shape . a ct scanner works by sending a fan or cone of x-rays through a patient to an array of detectors . the x-ray beam is rotated around the patient , and often also moved down the patient 's body , with the x-ray source tracing a spiral trajectory . spiral ct scans produce data that can be processed into cross sections detailed enough to spot anatomical features , tumors , blood clots , and infections .
|
a cross-section through which a patient can be reconstructed from _____ .
|
dating back at least to the time of socrates , some early societies decided that certain disputes , such as whether a person committed a particular crime , should be heard by a group of citizens . several centuries later , trial by jury was introduced to england , where it became a fundamental feature of the legal system , checking the government and involving citizens in decision-making . juries decided whether defendants would be tried on crimes , determined whether the accused defendants were guilty , and resolved monetary disputes . while the american colonies eventually cast off england 's rule , its legal tradition of the jury persisted . the united states constitution instructed a grand jury to decide whether criminal cases proceeded , required a jury to try all crimes , except impeachment , and provided for juries in civil cases as well . yet , in the us today , grand juries often are not convened , and juries decide less than 4 % of criminal cases and less than 1 % of civil cases filed in court . that 's at the same time as jury systems in other countries are growing . so what happened in the u.s. ? part of the story lies in how the supreme court has interpreted the constitution . it 's permitted plea bargaining , which now occurs in almost every criminal case . the way it works is the prosecutor presents the accused with a decision of whether to plead guilty . if they accept the plea , the case wo n't go in front of a jury , but they 'll receive a shorter prison sentence than they 'd get if a jury did convict them . the risk of a much greater prison sentence after a trial can frighten even an innocent defendant into taking a plea . between the 19th century and the 21st century , the proportion of guilty pleas has increased from around 20 % to 90 % , and the numbers continue to grow . the supreme court has permitted the use of another procedure that interferes with the jury called summary judgement . using summary judgement , judges can decide that civil trials are unnecessary if the people who sue have insufficient evidence . this is intended only for cases where no reasonable jury would disagree . that 's a difficult thing to determine , yet usage of summary judgement has stretched to the point where some would argue it 's being abused . for instance , judges grant fully , or in part , over 70 % of employers ' requests to dismiss employment discrimination cases . in other cases , both the person who sues and the person who defends forgo their right to go to court , instead resolving their dispute through a professional arbitrator . these are generally lawyers , professors , or former judges . arbitration can be a smart decision by both parties to avoid the requirements of a trial in court , but it 's often agreed to unwittingly when people sign contracts like employment applications and consumer agreements . that can become a problem . for example , some arbitrators may be biased towards the companies that give them cases . these are just some of the ways in which juries have disappeared . but could the disappearance of juries be a good thing ? well , juries are n't perfect . they 're costly , time-consuming , and may make errors . and they 're not always necessary , like when people can simply agree to settle their disputes . but juries have their advantages . when properly selected , jurors are more representative of the general population and do n't have the same incentives as prosecutors , legislators , or judges seeking reelection or promotion . the founders of the united states trusted in the wisdom of impartial groups of citizens to check the power of all three branches of government . and the jury trial itself has given ordinary citizens a central role in upholding the social fabric . so will the jury system in the u.s. survive into the future ?
|
part of the story lies in how the supreme court has interpreted the constitution . it 's permitted plea bargaining , which now occurs in almost every criminal case . the way it works is the prosecutor presents the accused with a decision of whether to plead guilty .
|
plea bargaining occurs in over __ percent of criminal cases .
|
translator : jenny zurawell i am awele . daughter of alice , granddaughter of ruth , great-granddaughter of big momma alice and madir corine , great-great-granddaughter of anna and zitii benyen . it is my hope to find my best possible self in the service of others . now , my daddy , he used to tell me stories . my daddy , he would say , `` i want you to know who you are and where you come from . that will guide you as you discover who you must be . now , you listen to this story , you hear me , baby girl ? it 's not going to be in a book . your teacher is not going to tell it , but you need to understand who you are . '' that became a guiding principle in the stories that i wanted to tell . stories about legacy of who we are . i used to hear all the time that children are the future , but what does that cliché really mean and how are we preparing them ? so i looked for narratives about young people and the legacy that they bring as agents of change . the power that you have right now . today , march 2 , 1955 -- the story that i want to share with you comes from 1955 , march 2 . it 's about a courageous 16-year-old girl , claudette colvin . and it comes full circle today because a week ago today , in san francisco , my middle school students , they performed a program that i had written , `` agents of change , '' starting with the reenactment of plessy v. ferguson from 1892 to 1896 , moving to brown v. board and a student-led strike by barbara rose johns , jumping to claudette colvin and the montgomery bus boycott and ending in 1960 with the sit-in movement , the non-violent movement led by students . so i 'm going to share the story , and i would like to also share the work i do with it , as a case study . i paid my dime at the front of the bus , and then i ran to the back door with the rest of the colored kids so the driver would n't take off before we got on . also , well , whites do n't want us walking down the aisle next to them . when i got back on the bus , colored section was full , so , i sat in the middle section . i took the last row seat on the left , it was right by the window , was n't thinking about anything in particular . `` hey . '' i did n't know the girl next to me either , this older girl . so i just looked out the window . driver went more stops , more people were getting on , colored and white . pretty soon , no more seats were available . `` give me those seats , '' the driver called out . colored folks just started getting up . white folks started taking their seats , but i stayed seated . girl next to me and the other two across -- they stayed seated . i knew it was n't the restricted area . `` make light on your feet ! '' girl next to me got up immediately . she stood in the aisle , then the other two girls . but i told myself , this is n't the restricted area . the driver , he looked up , looked in the window , that mirror . he pulled over . a pregnant lady , mrs. hamilton , got on the bus . she ran to the back and got on , not knowing he was trying to have me relinquish my seat . and she sat right next to me . `` the two of you need to get up so i can drive on . '' `` sir , i paid my dime , i paid my fare . it 's my right , you know , my constitutional -- '' `` constitutional ? ha-ha , let me get the police . '' well he got off and he flagged down two motormen , and they came . and those motormen , they came onto the bus . looked at mrs. hamilton . `` now the two of you need to get up so the driver can drive on . '' `` sir , i paid my dime . i 'm pregnant . if i were to move right now , i 'd be very sick , sir . '' `` sir , i paid my dime too , you know , and it 's my right , my constitutional right . i 'm a citizen of the united states . you just read the 13th and 14th amendment , it 'll tell you so . i know the law . my teacher , she taught it at school . '' you see , my teacher , she taught the constitution , the bill of rights , the declaration of independence , patrick henry 's speech -- i even memorized it . my teacher , she would prick our minds , trying to see what we thinking about . she would say , `` who are you ? hmm ? who are you , sitting right here right now ? the person that people think they see from your outside ? who are you on the inside ? how you think ? how you feel ? what you believe ? would you be willing to stand up for what you believe in even if someone wants to hold you back because you 're different ? do you love your beautiful brown skin , children ? hmm ? are you american ? what does it mean to be an american ? huh ? homework tonight , write me an essay : `` what does it mean to be an american ? '' you need to know who you are , children ! '' my teacher , she would teach us history and current events . she said that 's how we can understand everything that 's going on and we can do something about it . `` sir , all i know is i hate jim crow . i also know if i ai n't got nothing worth living for , i ai n't got nothing worth dying for . so give me liberty or give me death ! ouch ! i do n't care ! take me to jail . '' they dragged her off the bus . next thing , claudette colvin was in a car seat , backseat of the police car , handcuffed through the windows . the following year , may 11 , 1956 , claudette colvin was the star witness in the federal court case browder v. gayle . her , an 18-year-old teenager and two others , women , mrs. browder . their case , browder v. gayle , went up to the supreme court . on the heels of brown v. board of education , the 14th amendment and her powerful testimony that day , the rest is history . now , why is it we do n't know this story ? the montgomery bus boycott -- we hear rosa parks , martin luther king , they will forever be lifted up . but the role women played in that movement , the role of claudette , as an up-stander , it teaches us important lessons that challenge us today . what does it mean to be a participant ? a responsible citizen in a democracy ? and lessons of courage and of faith ? so i find freedom movement history that includes young people so that they can explore these big ideas of identity , your chosen identity , and the imposed identity . what does membership in society mean ? who has it ? how do we make amends ? race and violence in america , as well as participatory citizenship . so these stories allow me to have conversations , to speak the unspeakable , that many are afraid to have . once in eugene , oregon , a young , blond-haired , blue-eyed boy , middle schooler , at the end of a performance in the dialogue said , `` but ms. awele , racism 's over , right ? '' and not wanting to answer for him , i said , `` turn to the person sitting next to you . see if you can come up with evidence . '' and i gave them four minutes to talk . soon , they began to tell stories , evidence of racism in their community . a girl wrote to me , a high school student in san francisco : `` i was going to skip school but then i heard we had an assembly , so i came . and after listening to the students talk and seeing your performance , i thought i should organize my friends and we should go down to a board meeting and tell them that want to have advanced classes for a through g requirements . '' so , i tell you this story today in honor of the legacy of young people that have come before , so that they will have guideposts and signs to be the change that they want to see in this world , as claudette colvin was . because she struck down the constitutionality of segregated seats in montgomery , alabama . thank you . ( applause ) thank you . ( applause )
|
stories about legacy of who we are . i used to hear all the time that children are the future , but what does that cliché really mean and how are we preparing them ? so i looked for narratives about young people and the legacy that they bring as agents of change .
|
makeba is puzzled by the popular saying “ children are our future. ” she asks , “ what does that mean , and how are we really preparing them ? ” what does makeba think we can offer to help kids ?
|
translator : andrea mcdonough reviewer : bedirhan cinar these days scientists know how you inherit characteristics from your parents . they 're able to calculate probabilities of having a specific trait or getting a genetic disease according to the information from the parents and the family history . but how is this possible ? to understand how traits pass from one living being to its descendants , we need to go back in time to the 19th century and a man named gregor mendel . mendel was an austrian monk and biologist who loved to work with plants . by breeding the pea plants he was growing in the monastery 's garden , he discovered the principles that rule heredity . in one of most classic examples , mendel combined a purebred yellow-seeded plant with a purebred green-seeded plant , and he got only yellow seeds . he called the yellow-colored trait the dominant one , because it was expressed in all the new seeds . then he let the new yellow-seeded hybrid plants self-fertilize . and in this second generation , he got both yellow and green seeds , which meant the green trait had been hidden by the dominant yellow . he called this hidden trait the recessive trait . from those results , mendel inferred that each trait depends on a pair of factors , one of them coming from the mother and the other from the father . now we know that these factors are called alleles and represent the different variations of a gene . depending on which type of allele mendel found in each seed , we can have what we call a homozygous pea , where both alleles are identical , and what we call a heterozygous pea , when the two alleles are different . this combination of alleles is known as genotype and its result , being yellow or green , is called phenotype . to clearly visualize how alleles are distributed amongst descendants , we can a diagram called the punnett square . you place the different alleles on both axes and then figure out the possible combinations . let 's look at mendel 's peas , for example . let 's write the dominant yellow allele as an uppercase `` y '' and the recessive green allele as a lowercase `` y . '' the uppercase y always overpowers his lowercase friend , so the only time you get green babies is if you have lowercase y 's . in mendel 's first generation , the yellow homozygous pea mom will give each pea kid a yellow-dominant allele , and the green homozygous pea dad will give a green-recessive allele . so all the pea kids will be yellow heterozygous . then , in the second generation , where the two heterozygous kids marry , their babies could have any of the three possible genotypes , showing the two possible phenotypes in a three-to-one proportion . but even peas have a lot of characteristics . for example , besides being yellow or green , peas may be round or wrinkled . so we could have all these possible combinations : round yellow peas , round green peas , wrinkled yellow peas , wrinkled green peas . to calculate the proportions for each genotype and phenotype , we can use a punnett square too . of course , this will make it a little more complex . and lots of things are more complicated than peas , like , say , people . these days , scientists know a lot more about genetics and heredity . and there are many other ways in which some characteristics are inherited . but , it all started with mendel and his peas .
|
to understand how traits pass from one living being to its descendants , we need to go back in time to the 19th century and a man named gregor mendel . mendel was an austrian monk and biologist who loved to work with plants . by breeding the pea plants he was growing in the monastery 's garden , he discovered the principles that rule heredity . in one of most classic examples , mendel combined a purebred yellow-seeded plant with a purebred green-seeded plant , and he got only yellow seeds .
|
what did gregor mendel use to discover the principles that rule heredity ?
|
85 % of the matter in our universe is a mystery . we do n't know what it 's made of , which is why we call it dark matter . but we know it 's out there because we can observe its gravitational attraction on galaxies and other celestial objects . we 've yet to directly observe dark matter , but scientists theorize that we may actually be able to create it in the most powerful particle collider in the world . that 's the 27 kilometer-long large hadron collider , or lhc , in geneva , switzerland . so how would that work ? in the lhc , two proton beams move in opposite directions and are accelerated to near the speed of light . at four collision points , the beams cross and protons smash into each other . protons are made of much smaller components called quarks and gluons in most ordinary collisions , the two protons pass through each other without any significant outcome . however , in about one in a million collisions , two components hit each other so violently , that most of the collision energy is set free producing thousands of new particles . it 's only in these collisions that very massive particles , like the theorized dark matter , can be produced . the collision points are surrounded by detectors containing about 100 million sensors . like huge three-dimensional cameras , they gather information on those new particles , including their trajectory , electrical charge , and energy . once processed , the computers can depict a collision as an image . each line is the path of a different particle , and different types of particles are color-coded . data from the detectors allows scientists to determine what each of these particles is , things like photons and electrons . now , the detectors take snapshots of about a billion of these collisions per second to find signs of extremely rare massive particles . to add to the difficulty , the particles we 're looking for may be unstable and decay into more familiar particles before reaching the sensors . take , for example , the higgs boson , a long-theorized particle that was n't observed until 2012 . the odds of a given collision producing a higgs boson are about one in 10 billion , and it only lasts for a tiny fraction of a second before decaying . but scientists developed theoretical models to tell them what to look for . for the higgs , they thought it would sometimes decay into two photons . so they first examined only the high-energy events that included two photons . but there 's a problem here . there are innumerable particle interactions that can produce two random photons . so how do you separate out the higgs from everything else ? the answer is mass . the information gathered by the detectors allows the scientists to go a step back and determine the mass of whatever it was that produced two photons . they put that mass value into a graph and then repeat the process for all events with two photons . the vast majority of these events are just random photon observations , what scientists call background events . but when a higgs boson is produced and decays into two photons , the mass always comes out to be the same . therefore , the tell-tale sign of the higgs boson would be a little bump sitting on top of the background . it takes billions of observations before a bump like this can appear , and it 's only considered a meaningful result if that bump becomes significantly higher than the background . in the case of the higgs boson , the scientists at the lhc announced their groundbreaking result when there was only a one in 3 million chance this bump could have appeared by a statistical fluke . so back to the dark matter . if the lhc 's proton beams have enough energy to produce it , that 's probably an even rarer occurrence than the higgs boson . so it takes quadrillions of collisions combined with theoretical models to even start to look . that 's what the lhc is currently doing . by generating a mountain of data , we 're hoping to find more tiny bumps in graphs that will provide evidence for yet unknown particles , like dark matter . or maybe what we 'll find wo n't be dark matter , but something else that would reshape our understanding of how the universe works entirely . that 's part of the fun at this point . we have no idea what we 're going to find .
|
in the case of the higgs boson , the scientists at the lhc announced their groundbreaking result when there was only a one in 3 million chance this bump could have appeared by a statistical fluke . so back to the dark matter . if the lhc 's proton beams have enough energy to produce it , that 's probably an even rarer occurrence than the higgs boson .
|
what is dark matter made of ?
|
so here you can see we have a very thin foil sample of dysprosium . again it is from the bottom end of the periodic table , very , very reactive . stored very , very carefully as a foil . now if we open , very carefully , we might see if the metal is still there . ok so dysprosium is used in nuclear fuel rods because it is very good at capturing neutrons , which means that you can modulate how hot a nuclear reaction is getting which is why it is used in powerstations to prevent the reactions from running away out of control . so take off all this foil and then we can withdraw the sample . so it is in this really nice paper . so is the sample still there ? oh beautiful , here we see this wonderful sample of dysprosium . if you mix dysprosium with cadmium and sulphur it can be used in devices which produce infrared beams . now chemists use infrared beams quite a lot because when you irradiate a sample , a compound with infrared then certain absorbencies will occur which are specific to stretching or bending modes which the molecule will do . this is a way of , therefore , scanning molecules and getting information about their composition and structure . beautiful foil . do you happen to know anything about this element ? not a thing , that ’ s steve ’ s domain . yeah !
|
so is the sample still there ? oh beautiful , here we see this wonderful sample of dysprosium . if you mix dysprosium with cadmium and sulphur it can be used in devices which produce infrared beams . now chemists use infrared beams quite a lot because when you irradiate a sample , a compound with infrared then certain absorbencies will occur which are specific to stretching or bending modes which the molecule will do .
|
which analytical technique does stephen explain uses the element dysprosium together with cadmium and sulfur ?
|
translator : andrea mcdonough reviewer : bedirhan cinar mysteries of vernacular tuxedo : men 's evening wear for semi-formal occasions . tuxedo , surprisingly , has its roots in native american history . the delaware indians of what is now the northeast united states , were divided into three subgroups , distinguished by their animal totems : the turkey , the turtle , and the wolf . members of the tribe belonging to the wolf totem were often referred to by the indigenous word for the four-footed canine , p'tuksit . in the 18th century , europeans who settled in the former region of the p'tuksit anglicized the name as `` tuxedo '' and slapped it on a town in southeast new york . decades later , in the late 1800s , a lavish resort was constructed and christened `` the tuxedo club '' . it was at the tuxedo club , around the turn of the century , when a dress jacket was required for almost every occasion , that a brash young man , heir to an enormous tobacco fortune , caused a stir by flaunting tradition and donning a formal dinner jacket without tails . his bold fashion statement was quickly popularized and nicknamed tuxedo , which in modern america , is the headache of high school prom attendees across the nation .
|
the delaware indians of what is now the northeast united states , were divided into three subgroups , distinguished by their animal totems : the turkey , the turtle , and the wolf . members of the tribe belonging to the wolf totem were often referred to by the indigenous word for the four-footed canine , p'tuksit . in the 18th century , europeans who settled in the former region of the p'tuksit anglicized the name as `` tuxedo '' and slapped it on a town in southeast new york .
|
what does it mean to anglicize a word ?
|
hey , vsauce . michael here . when you call customer service and hear this `` to ensure quality service your call may be monitored or recorded '' , they 're not kidding . over the last year the marchex institute analysed more than 600,000 recorded phone conversations americans made to businesses in the united states . turns out , people from ohio were the most likely to use curse words - the 'a ' word , the 'f ' word and the 's ' word . washington state residents were the least likely to use bad words . but what makes a word bad ? oh , be careful because etymologically speaking even the word 'bad ' can be considered a bad word . it began in old english as a derogatory term for an effeminate man . eighty percent of swear words overheard in public in 1986 , 1997 and 2006 were essentially the same . one third of all counts included the top two - the 'f ' word and the 's ' word . slate 's brilliant lexicon valley podcast purported that these 10 words makeup about 0.7 % of the average english speakers daily vocabulary , which means socially unacceptable words are used almost as often as socially descriptive words . first person plural pronouns account for about 1 % of the words we say everyday . when a bad word is bleeped , it is covered with a 1 kilohertz sine wave , which sounds like this . son of a ... by the way , the symbols and squiggles that are used to represent a bad word have a name . they 're called grawlixes . they were named by mort walker in his seminal `` the lexicon of comicana . '' he names a lot of things but most of them show stuff , they do n't hide stuff . why the need to hide bad words , especially if we all pretty much know what 's being said ? well , there is no one single reason bad words are bad . steven pinker in his excellent lecture on the topic delineates five types of swearing . first of all , some words are bad on purpose . they are created and/or used with the intent to hurt others . he calls this `` abusive swearing . '' using words to insult , humiliate , objectify or marginalise disfavoured people . now , if that this disfavoured person is god , we 're talking about supernatural swearing , which was particularly taboo in victorian times . it was believed that casually or vainly referring to god would physically injure god himself , literally . so , at the time people were forced to come up with euphemisms , like `` zounds ! '' and `` gadzooks ! `` , which originally meant `` god 's wounds ! '' and `` god 's hooks ! `` , referring to the nails driven through the hands of jesus . historically , swear words often came from things we were afraid of , things we perceived as dangerous , stronger than us and mercurial . such as death , disease and infirmity , sex and sexually transmitted diseases , as well as body fluids , germy , gross effluvia . words for those gross things became gross and bad in and of themselves , uncouth to speak . but not all words for gross things are socially unacceptable , which brings us to pinker 's second type of swearing - emphatic swearing . emphatic swearing is where the taboo-ness of bad words becomes quite practical . you would n't usually use those words but when you really want to convey that your current emotions matter more to you than proper social conduct , you can use them . dysphemism . a euphemism is kind , acceptable word that allows you to talk about something unpleasant while simultaneously letting everyone know you totally get that it 's unpleasant and want to respect that . for instance , if you want to be professional , you would n't say s*** . you might say 'defecate ' . if , on the other hand , you really want to drive home just how unpleasant the experience was , dysphemisms can help out a lot . it was n't a bag of canine defecation you found on your front porch , it was a s*** bag of hot dog s*** . both of these words refer to pretty much the same thing but they have different levels of social acceptability and that 's very helpful . it means word choice allows us to not only refer to things in the real world but also to how we feel about them . if both these words had the same level of social acceptance we might even have to find new , badder words so as not to lose the power language currently has to express emotion , repulsion and disgust . but when it comes to two words referring to the same thing , but with different levels of social acceptance , who decides which one 's good and which one 's bad ? well , historically , many of the bad words we use today are the result of class differences . in medieval england , the lower-class saxons spoke a germanic tongue while the upper-class normans spoke a language related to french and latin . english , as we know it today , contains many consequences of their differences . the lower class worked with animals and from them we get animal names . the upper class only ate the animals , which is where the names of the meat come from . today 's swear words are similar . defecation stems from fancy pants latin , whereas the less classy s*** is germanic . there 's also idiomatic swearing , where nothing is being emphasized . no dysphemism is meant ; instead , it 's an easygoing type of swearing that shows an atmosphere is casual . bad words can be used , we 're all close here . it 's okay to swear , we 're all cool . cathartic swearing is a bit different . it gives us `` lalochezia , '' the medical term for the relief swearing provides when you 're in pain . in the brain , swearing seems to involve different regions than regular language , which may explain why people with aphasia caused by brain damage struggle to comprehend or construct spoken words but yet are fluent at swearing . or why people with coprolalia control normal language just fine , but involuntarily utter profanity , an obscene words . it turns out swearing may be centralized in the limbic system , along with the motions . many animals make automatic noises when in pain or threat to startle or intimidate attackers , or to let others know what 's going on . in humans , bad words are great for this purpose . their taboo-ness makes them special . people would n't use them otherwise , so they are great alarms . swearing is changing . some bad words are being used more and more frequently . of the seven words , george carlin said you could never say on television . today , every second 22 of them are sent out on twitter . so , what will swearing look like in the future ? it probably wo n't go away altogether , it 's too useful . but the words we do n't like will likely change . history has shown that as disease becomes less scary and sex and the supernatural more personal , words related to them become less taboo and more common ; whereas words that were common in the past are increasingly unpleasant . perhaps , in the future , spurt not by runaway political correctness but by wider knowledge , words like `` schizo '' , `` mental '' , `` aspy '' , or even `` depressed '' will take the square stage . or as john mcwhorter ventured , words centered around class and the gap between opportunity and disadvantage will become more taboo . salt of the earth , trash , chav , pikey , urban as a pejorative . when mckay hatch started a `` no cussing club '' at his school , his campaign became the target of so many online jokes and insults for being lame or anti-free speech . on his book , he literally subtitled his own name `` the most cyberbullied kid in the world . '' people care about this stuff . is it censorship to tell us what we can and can not say or is it a safety seal , ensuring certain dysphemisms do n't get worn down to a quotidian bluntness like every other word ? or is that badness of bad words a boundary , a moving boundary of we reject - sometimes arbitrary , sometimes irrational , but always moving in the direction of acceptance moving forward ? crime and inequality have existed ever since they could . but when n.w.a released a reaction , in the form of a song with bad word in the title , `` f*** the police '' , the federal bureau of investigations released a statement against the song . it was the only time , up until then and since , the fbi has ever issued an official statement about a work of art . bad words have power . if you wan na push for change you 'll need something to push . if everything 's fine , nothing 's cool . so , bad words are the precipitate of a larger reaction - the process of us slowly becoming what we want to become . that 's some deep s*** . and as always , thanks for watching .
|
one third of all counts included the top two - the 'f ' word and the 's ' word . slate 's brilliant lexicon valley podcast purported that these 10 words makeup about 0.7 % of the average english speakers daily vocabulary , which means socially unacceptable words are used almost as often as socially descriptive words . first person plural pronouns account for about 1 % of the words we say everyday .
|
the top ten swear words make up what percentage of the average english speaker 's daily conversation ?
|
many of the inanimate objects around you probably seem perfectly still . but look deep into the atomic structure of any of them , and you 'll see a world in constant flux . stretching , contracting , springing , jittering , drifting atoms everywhere . and though that movement may seem chaotic , it 's not random . atoms that are bonded together , and that describes almost all substances , move according to a set of principles . for example , take molecules , atoms held together by covalent bonds . there are three basic ways molecules can move : rotation , translation , and vibration . rotation and translation move a molecule in space while its atoms stay the same distance apart . vibration , on the other hand , changes those distances , actually altering the molecule 's shape . for any molecule , you can count up the number of different ways it can move . that corresponds to its degrees of freedom , which in the context of mechanics basically means the number of variables we need to take into account to understand the full system . three-dimensional space is defined by x , y , and z axes . translation allows the molecule to move in the direction of any of them . that 's three degrees of freedom . it can also rotate around any of these three axes . that 's three more , unless it 's a linear molecule , like carbon dioxide . there , one of the rotations just spins the molecule around its own axis , which does n't count because it does n't change the position of the atoms . vibration is where it gets a bit tricky . let 's take a simple molecule , like hydrogen . the length of the bond that holds the two atoms together is constantly changing as if the atoms were connected by a spring . that change in distance is tiny , less than a billionth of a meter . the more atoms and bonds a molecule has , the more vibrational modes . for example , a water molecule has three atoms : one oxygen and two hydrogens , and two bonds . that gives it three modes of vibration : symmetric stretching , asymmetric stretching , and bending . more complicated molecules have even fancier vibrational modes , like rocking , wagging , and twisting . if you know how many atoms a molecule has , you can count its vibrational modes . start with the total degrees of freedom , which is three times the number of atoms in the molecule . that 's because each atom can move in three different directions . three of the total correspond to translation when all the atoms are going in the same direction . and three , or two for linear molecules , correspond to rotations . all the rest , 3n-6 or 3n-5 for linear molecules , are vibrations . so what 's causing all this motion ? molecules move because they absorb energy from their surroundings , mainly in the form of heat or electromagnetic radiation . when this energy gets transferred to the molecules , they vibrate , rotate , or translate faster . faster motion increases the kinetic energy of the molecules and atoms . we define this as an increase in temperature and thermal energy . this is the phenomenon your microwave oven uses to heat your food . the oven emits microwave radiation , which is absorbed by the molecules , especially those of water . they move around faster and faster , bumping into each other and increasing the food 's temperature and thermal energy . the greenhouse effect is another example . some of the solar radiation that hits the earth 's surface is reflected back to the atmosphere . greenhouse gases , like water vapor and carbon dioxide absorb this radiation and speed up . these hotter , faster-moving molecules emit infrared radiation in all directions , including back to earth , warming it . does all this molecular motion ever stop ? you might think that would happen at absolute zero , the coldest possible temperature . no one 's ever managed to cool anything down that much , but even if we could , molecules would still move due to a quantum mechanical principle called zero-point energy . in other words , everything has been moving since the universe 's very first moments , and will keep going long , long after we 're gone .
|
so what 's causing all this motion ? molecules move because they absorb energy from their surroundings , mainly in the form of heat or electromagnetic radiation . when this energy gets transferred to the molecules , they vibrate , rotate , or translate faster .
|
molecules move faster when they absorb energy in the form of heat or electromagnetic radiation . what do you think will happen to a molecule in case it will absorb a really large amount of energy ? can you think of an example for such a large energy source ?
|
to survive in this high pressured , crazy world most of us have to become highly adept at self-criticism . we learn how to tell ourselves off for our failures and for not working hard or smart enough . but so good are we at this that we 're sometimes in danger of falling prey to an excessive form of self-criticism what we might call self-flagellation a rather dangerous state which just ushers in depression and under-performance . we might simply lose the will to get out of bed . for those moments , we need a corrective . we need to carve out time for an emotional state of which many of us are profoundly suspicious . self-compassion . we 're suspicious because that sounds horribly close to self-pity but because depression and self-hatred are serious enemies of a good life , we need to appreciate the role of self-care in a good , ambitious and fruitful life . to this end we can perform what we 've called a , `` self-compassion exercise '' a structured meditation , lasting 15 minutes or so lying in bed , or perhaps a bath turn over a sequence of thoughts that interrupt and correct the flow of your worse self-accusations . for a time adopt an entire kindly perspective on your setbacks the self compassion exercise goes like this : we 're so in love with success we fail to notice the scale of the challenges we routinely set ourselves . there is nothing remotely normal about what we 've tried to achieve . we 've failed , but given the mountain we were trying to climb , the conclusion does n't have to be that we 're simply flawless . we have tricky family histories , we all do . there were things which happened to us at the hands of others which can help to explain some of our current troubles . we 're not entirely sane or well , but none of us are . we were n't well set up to carry out certain tasks it is n't wholly our fault in the here and now . from the media , you 'd think everyone was rich and famous and successful . but in reality , undramatic , quiet failure is by a huge margin the statistical norm . we should n't tear ourselves apart for not managing to be to what were in truth , awesome odds . tough , self-critical people do n't allow themselves the indulgence of believing in luck . they take responsibility for everything . they think winners make their own luck but they do n't for the most part . luck is a genuine feature of existence we 're robbing ourselves of fair concilation by believing that we 're entirely in control , and therefore entirely to blame when we crash . you are not only your achievements . status and material success are one bit of you . but there are others as well , those who loved you in childhood knew this , and in their best moments helped you to feel it . rehearse the internalized voices of all those who have been kind to you . bathe in the memory of a laugh independent of achievement . it seems it will never end that 's not the truth it 's just how a crisis feels . you need to reduce expectations to zero for a time . take each new hour as it comes , and without being banal , what you need most of all , is some rest .
|
we need to carve out time for an emotional state of which many of us are profoundly suspicious . self-compassion . we 're suspicious because that sounds horribly close to self-pity but because depression and self-hatred are serious enemies of a good life , we need to appreciate the role of self-care in a good , ambitious and fruitful life .
|
how long does it take to do this exercise in self-compassion ?
|
imagine a police lineup where ten witnesses are asked to identify a bank robber they glimpsed fleeing the crime scene . if six of them pick out the same person , there 's a good chance that 's the real culprit , and if all ten make the same choice , you might think the case is rock solid , but you 'd be wrong . for most of us , this sounds pretty strange . after all , much of our society relies on majority vote and consensus , whether it 's politics , business , or entertainment . so it 's natural to think that more consensus is a good thing . and up until a certain point , it usually is . but sometimes , the closer you start to get to total agreement , the less reliable the result becomes . this is called the paradox of unanimity . the key to understanding this apparent paradox is in considering the overall level of uncertainty involved in the type of situation you 're dealing with . if we asked witnesses to identify the apple in this lineup , for example , we should n't be surprised by a unanimous verdict . but in cases where we have reason to expect some natural variance , we should also expect varied distribution . if you toss a coin one hundred times , you would expect to get heads somewhere around 50 % of the time . but if your results started to approach 100 % heads , you 'd suspect that something was wrong , not with your individual flips , but with the coin itself . of course , suspect identifications are n't as random as coin tosses , but they 're not as clear cut as telling apples from bananas , either . in fact , a 1994 study found that up to 48 % of witnesses tend to pick the wrong person out of a lineup , even when many are confident in their choice . memory based on short glimpses can be unreliable , and we often overestimate our own accuracy . knowing all this , a unanimous identification starts to seem less like certain guilt , and more like a systemic error , or bias in the lineup . and systemic errors do n't just appear in matters of human judgement . from 1993-2008 , the same female dna was found in multiple crime scenes around europe , incriminating an elusive killer dubbed the phantom of heilbronn . but the dna evidence was so consistent precisely because it was wrong . it turned out that the cotton swabs used to collect the dna samples had all been accidentally contaminated by a woman working in the swab factory . in other cases , systematic errors arise through deliberate fraud , like the presidential referendum held by saddam hussein in 2002 , which claimed a turnout of 100 % of voters with all 100 % supposedly voting in favor of another seven-year term . when you look at it this way , the paradox of unanimity is n't actually all that paradoxical . unanimous agreement is still theoretically ideal , especially in cases when you 'd expect very low odds of variability and uncertainty , but in practice , achieving it in situations where perfect agreement is highly unlikely should tell us that there 's probably some hidden factor affecting the system . although we may strive for harmony and consensus , in many situations , error and disagreement should be naturally expected . and if a perfect result seems too good to be true , it probably is .
|
and up until a certain point , it usually is . but sometimes , the closer you start to get to total agreement , the less reliable the result becomes . this is called the paradox of unanimity .
|
brainstorm a scenario from everyday life where 100 % agreement of a lot people is a lot less much more likely to be correct than if , say , 75 % agreed and 25 % disagreed .
|
translator : andrea mcdonough reviewer : jessica ruby we all start life as one single cell . then that cell divides and we are two cells , then four , then eight . cells form tissues , tissues form organs , organs form us . `` so , how did you guys decide , like , what style to use when animating this video ? '' `` i , originally , when i was reading the script , i was thinking a lot about food . '' `` were you hungry ? '' `` i was hungry probably because i always am . but , yeah , i was thinking about healthy food and thinking of how can i use material , how could i actually materialize that cell , the cancer cell and the healthy cell . so , i decided to use grain and seeds for healthy cells and , then , for the cancer cells , actually , we decided to use candy . we did a little short animation before this when we were using different color jelly beans to animate bacteria , so i thought , 'oh , well , we can use that . ' but , then , the jelly beans were actually , like , a little too big to construct this cell . and , so , i decided to go with something smaller , and we found nerds . lisa can actually tell you a little more about how she designed each cell . '' `` yeah , when we were , we had a whole collection of seeds and candy nerds in front of us . so , we actually ended up using buckwheat and lentils for the healthy cells . and then for the candy nerds , they were really a perfect size . we got to play with the colors and switch them around to make those cells look a little more alive like they were constantly changing . so , it really had a more erratic look than the seeds , which were natural colors , but that would also stay consistent throughout . '' `` are these actually ? '' `` those are the actual things . so , those , as you see , probably , like , come in pink , orange , yellow , green , all these colors . so , i wanted to create the image of a cancer cell as something that is bad . so , we actually shot these things as they are and then changed the hue in the computer so they appear more neon blue and toxic in a way . '' `` and it was n't just food , right ? there were also other materials that you guys used ? '' `` right . '' `` there was , so there was a part in the video that talked about tissue and organs and i stayed within that same idea and thought like , 'which natural material i can use to construct these objects ? ' and then i think for the tissue , we used something that was like a lacy pattern , and then for the rest of it , it was mostly knitted yarn or crocheted yarn . so , those were the materials . so , we will see in the human body , because we do not really have the skills or the time to actually crochet these things , our artist , celeste , actually crocheted her organs in photoshop . so , we would take these patterns from some stock that we found online , and she did step-by-step and she actually , like , made it into the shape of an organ . so , those were the materials we used . ''
|
so , we actually shot these things as they are and then changed the hue in the computer so they appear more neon blue and toxic in a way . '' `` and it was n't just food , right ? there were also other materials that you guys used ? ''
|
why do you think biljana choose to use food in the design concept for this lesson ?
|
when we watch a film or a play , we know that the actors probably learned their lines from a script , which essentially tells them what to say and when to say it . a piece of written music operates on exactly the same principle . in a very basic sense , it tells a performer what to play and when to play it . aesthetically speaking , there 's a world of difference between , say , beethoven and justin bieber , but both artists have used the same building blocks to create their music : notes . and although the end result can sound quite complicated , the logic behind musical notes is actually pretty straightforward . let 's take a look at the foundational elements to music notation and how they interact to create a work of art . music is written on five parallel lines that go across the page . these five lines are called a staff , and a staff operates on two axes : up and down and left to right . the up-and-down axis tells the performer the pitch of the note or what note to play , and the left-to-right axis tells the performer the rhythm of the note or when to play it . let 's start with pitch . to help us out , we 're going to use a piano , but this system works for pretty much any instrument you can think of . in the western music tradition , pitches are named after the first seven letters of the alphabet , a , b , c , d , e , f , and g. after that , the cycle repeats itself : a , b , c , d , e , f , g , a , b , c , d , e , f , g , and so on . but how do these pitches get their names ? well , for example , if you played an f and then played another f higher or lower on the piano , you 'd notice that they sound pretty similar compared to , say , a b . going back to the staff , every line and every space between two lines represents a separate pitch . if we put a note on one of these lines or one of these spaces , we 're telling a performer to play that pitch . the higher up on the staff a note is placed , the higher the pitch . but there are obviously many , many more pitches than the nine that these lines and spaces gives us . a grand piano , for example , can play 88 separate notes . so how do we condense 88 notes onto a single staff ? we use something called a clef , a weird-looking figure placed at the beginning of the staff , which acts like a reference point , telling you that a particular line or space corresponds to a specific note on your instrument . if we want to play notes that are n't on the staff , we kind of cheat and draw extra little lines called ledger lines and place the notes on them . if we have to draw so many ledger lines that it gets confusing , then we need to change to a different clef . as for telling a performer when to play the notes , two main elements control this : the beat and the rhythm . the beat of a piece of music is , by itself , kind of boring . it sounds like this . ( ticking ) notice that it does n't change , it just plugs along quite happily . it can go slow or fast or whatever you like , really . the point is that just like the second hand on a clock divides one minute into sixty seconds , with each second just as long as every other second , the beat divides a piece of music into little fragments of time that are all the same length : beats . with a steady beat as a foundation , we can add rhythm to our pitches , and that 's when music really starts to happen . this is a quarter note . it 's the most basic unit of rhythm , and it 's worth one beat . this is a half note , and it 's worth two beats . this whole note here is worth four beats , and these little guys are eighth notes , worth half a beat each . `` great , '' you say , `` what does that mean ? '' you might have noticed that across the length of a staff , there are little lines dividing it into small sections . these are bar lines and we refer to each section as a bar . at the beginning of a piece of music , just after the clef , is something called the time signature , which tells a performer how many beats are in each bar . this says there are two beats in each bar , this says there are three , this one four , and so on . the bottom number tells us what kind of note is to be used as the basic unit for the beat . one corresponds to a whole note , two to a half note , four to a quarter note , and eight to an eighth note , and so on . so this time signature here tells us that there are four quarter notes in each bar , one , two , three , four ; one , two , three , four , and so on . but like i said before , if we just stick to the beat , it gets kind of boring , so we 'll replace some quarter notes with different rhythms . notice that even though the number of notes in each bar has changed , the total number of beats in each bar has n't . so , what does our musical creation sound like ? ( music ) eh , sounds okay , but maybe a bit thin , right ? let 's add another instrument with its own pitch and rhythm . now it 's sounding like music . sure , it takes some practice to get used to reading it quickly and playing what we see on our instrument , but , with a bit of time and patience , you could be the next beethoven or justin bieber .
|
music is written on five parallel lines that go across the page . these five lines are called a staff , and a staff operates on two axes : up and down and left to right . the up-and-down axis tells the performer the pitch of the note or what note to play , and the left-to-right axis tells the performer the rhythm of the note or when to play it . let 's start with pitch .
|
the left/right axis on a staff tells a performer :
|
we are here in the basement of the royal society in london , the royal society is the uk national academy for sciences and we are here because there is an exhibition about rutherford . we are interested in the element rutherfordium which is right here at the bottom of the periodic table number 104 , and with these elements only tiny amounts , relatively few atoms have been made so we can ’ t tell you about how it is used in light bulbs or something like that because it has not been used for anything . people are really excited if they make one or two atoms of it . so instead we are going to tell you a bit about rutherford after whom it ’ s named . and rutherford is famous because he did a whole series of experiments , or he and his co-workers , that really explained the structure of atoms and so the periodic table for the first time really began to make sense . over here you can see there is a picture of rutherford here in his lab with one of his co-workers and this is a very famous picture . rutherford , who came from new zealand , had a very loud voice and the experiments were rather sensitive , if you talked too loud the apparatus started shaking and it did not work properly , so his students put up a big notice in the lab saying talk softly please . but i am not sure that it stopped him and i use this picture when i am talking to my students about safety , you ’ ve always got to be really safe when you are working as a chemist . first of all you can see that rutherford is smoking in the lab and then he is not wearing safety glasses , nor is his colleague , and then they have a whole series of wires and all sorts of things to trip over . so it is really surprising that they managed to get their experiments to work without some sort of serious accident . perhaps they did break things and never told us about it . anyway rutherford ’ s work was recognised by him winning the nobel prize and here , and it is quite exciting , there is a replica of the nobel prize . the nobel prize is a gold medal but here they have shown it as two half-medals , underneath there is nothing to see , so you can see both of the sides . so on one side there is the portrait of alfred nobel , whose money and foundation , still to this day , pays for prize money , when he received this it would have been presented to him by the swedish king in a huge ceremony in stockholm . now what i can ’ t remember is whether he got the nobel prize for physics or chemistry . i have a feeling… chemistry ! yes . i have a feeling that he got it for chemistry which was particularly funny because rutherford didn ’ t like chemistry . he said that there is just physics and stamp collecting and he did not really respect chemistry so perhaps the chemists got their revenge by giving him the nobel prize for chemistry . now rutherford had very strong views about the hours his students should work and they were not allowed to work after 6 o ’ clock at night in the lab and his chief technician would go round the lab at 6 o ’ clock and switch off all the apparatus and chase everybody out of the lab . and even though they did this , 11 of his students won nobel prizes ; this must be one of the records for any single research group to this day . and of course when they went home having had dinner and drank wine in the college then they started working writing papers . but it is very interesting that if you read letters from visiting american scientists they could not understand how rutherford ’ s lab was so successful because the people came in at 10 o ’ clock in the morning they went home at 6 , and did not seem to do any work at all , but they discovered all these wonderful things . what ’ s your policy on your students working then ? well i always encourage my students to work but i find that if i encourage them too hard , it has the opposite effect , just like parents telling children to do their homework but by and large when people are enthusiastic about their science it is difficult to stop them working too much . as part of this exhibition they have got some postcards of rutherford and this one has got , i think it is really terrific , shows rutherford in the sea . but i really like this because it shows that famous scientists sometimes take time off and they don ’ t always behave like white-coated figures in labs , but they do have a human side as well .
|
people are really excited if they make one or two atoms of it . so instead we are going to tell you a bit about rutherford after whom it ’ s named . and rutherford is famous because he did a whole series of experiments , or he and his co-workers , that really explained the structure of atoms and so the periodic table for the first time really began to make sense .
|
after which great scientist was rutherfordium named ?
|
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 .
|
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 .
|
billy weighs twice as much as jasmine . where should they place the fulcrum if they want to balance out the teeter-totter ? write an equation that models the situation from the previous question . explain how your equation models it correctly .
|
translator : ted translators admin reviewer : ivana korom hello everyone , my name is thomas suarez . i 've always had a fascination for computers and technology , and i made a few apps for the iphone , ipod touch , and ipad . i 'd like to share a couple with you today . my first app was a unique fortune teller called earth fortune that would display different colors of earth depending on what your fortune was . my favorite and most successful app is bustin jieber - ( laughter ) - which is a justin bieber whac-a-mole . i created it because a lot of people at school disliked justin bieber a little bit , so i decided to make the app . so i went to work programming it , and i released it just before the holidays in 2010 . a lot of people ask me , how did i make these ? a lot of times it 's because the person who asked the question wants to make an app also . a lot of kids these days like to play games , but now they want to make them , and it 's difficult , because not many kids know where to go to find out how to make a program . i mean , for soccer , you could go to a soccer team . for violin , you could get lessons for a violin . but what if you want to make an app ? and the kid 's parents might have done some of these things when they were young , but not many parents have written apps . ( laughter ) where do you go to find out how to make an app ? well , this is how i approached it . this is what i did . first of all , i 've been programming in multiple other programming languages to get the basics down , such as python , c , java , etc . and then apple released the iphone , and with it , the iphone software development kit , and the software development kit is a suite of tools for creating and programming an iphone app . this opened up a whole new world of possibilities for me , and after playing with the software development kit a little bit , i made a couple apps , i made some test apps . one of them happened to be earth fortune , and i was ready to put earth fortune on the app store , and so i persuaded my parents to pay the 99 dollar fee to be able to put my apps on the app store . they agreed , and now i have apps on the app store . i 've gotten a lot of interest and encouragement from my family , friends , teachers and even people at the apple store , and that 's been a huge help to me . i 've gotten a lot of inspiration from steve jobs , and i 've started an app club at school , and a teacher at my school is kindly sponsoring my app club . any student at my school can come and learn how to design an app . this is so i can share my experiences with others . there 's these programs called the ipad pilot program , and some districts have them . i 'm fortunate enough to be part of one . a big challenge is , how should the ipads be used , and what apps should we put on the ipads ? so we 're getting feedback from teachers at the school to see what kind of apps they 'd like . when we design the app and we sell it , it will be free to local districts and other districts that we sell to , all the money from that will go into the local ed foundations . these days , students usually know a little bit more than teachers with the technology . ( laughter ) so - ( laughter ) - sorry - ( laughter ) - so this is a resource to teachers , and educators should recognize this resource and make good use of it . i 'd like to finish up by saying what i 'd like to do in the future . first of all , i 'd like to create more apps , more games . i 'm working with a third party company to make an app . i 'd like to get into android programming and development , and i 'd like to continue my app club , and find other ways for students to share knowledge with others . thank you . ( applause )
|
i 'd like to share a couple with you today . my first app was a unique fortune teller called earth fortune that would display different colors of earth depending on what your fortune was . my favorite and most successful app is bustin jieber - ( laughter ) - which is a justin bieber whac-a-mole .
|
describe what the earth fortune app does .
|
albert einstein . the icon of genius . why ? because he figured out e equals m c squared ? because he did n't like socks ? nope ! because he came up with the most powerful idea in science.. general relativity his masterpiece is now 100 years old . and while the physicists are partying , the rest of us are left wondering what the bleep it ’ s all about ! well here goes . at 26 he figured out nothing less than a new theory of space and time . it led to a nifty way of simplifying physics – by treating space and time as one thing ... spacetime ! but albert was just warming up . he wasn ’ t happy with isaac newton ’ s mysterious force of gravity . naturally , he started work on his own theory . and sure enough , he cracked it . mass causes spacetime to curve ! the natural motion of things is to follow the simplest path through spacetime . but since objects with mass curve spacetime , stuff moves towards the most massive objects . that ’ s what you feel as gravity . it ’ s warped space and time that ’ s keeping your feet on the ground . “ warped space ” might sound too sci-fi to be true . but we can measure the bending of starlight as is passes through the warped space around the sun . warped time sounds even more ridiculous . but take an accurate clock to the top of a building and you ’ ll see it runs slightly quicker than one on the ground ! that ’ s because as you move away from the centre of the planet space and time are less warped . most amazing of all , einstein ’ s theory told us that our universe has a beginning . everything is expanding out from a hot dense origin 13.8 billion years ago . but here ’ s the catch : we ’ ve spotted that the universe is expanding faster than albert ’ s theory predicts . could the old genius be wrong ? to stick with his idea we ’ ve had to invent a made up energy - ‘ dark energy ’ - to account for the speedy expansion . and we ’ ve had to assume there ’ s an exotic form of ‘ dark matter ' we haven ’ t detected yet either . these two unknowns should make up 95 % of the universe – yet we ’ ve never detected them . that ’ s the sort of thing that keeps physicists awake at night . so they ’ re plotting some seriously big experiments to put albert ’ s theory to the ultimate test . for the last 100 years , uncle albert ’ s great theory has passed every test possible . if it succeeds again physicists will party . if they find its limits and it finally fails they ’ ll party too . physicists are funny like that .
|
albert einstein . the icon of genius .
|
according to einstein , the universe is expanding away from the site of an initial 'big bang ' , but the universe is expanding much more rapidly than einstein predicted . what theory have physicists invented to explain this ?
|
translator : tom carter reviewer : bedirhan cinar most people have heard the word `` gerrymandering '' once or twice , probably during a presidential election . what exactly is gerrymandering ? essentially , it 's the process of giving one political party an advantage over another political party by redrawing district lines . it 's like democrats trying to gain an advantage over republicans , or republicans trying to gain an advantage over democrats . you see , each party wants to gain as many districts as possible so they can do things like control the state budget , or set themselves up to win even more districts in the future . so to understand how this process began , and how it continues today , we must go back to 1812 in massachusetts . elbridge gerry , the governor of massachusetts , supported and signed a bill to allow redistricting . that is , redrawing the boundaries that separate districts . the catch ? the new lines would favor gerry 's own political party , the democratic-republican party , which no longer exists . you see , gerry wanted his party to win as many state senate seats as possible . the more members of your party who vote , the more likely you are to win an election . the new lines were drawn to include loads of areas that would help governor gerry in the future . they were so strange looking that someone said the new districts looked like a salamander . the boston gazette added gerry 's name to the word salamander , and voilà ! gerrymandering , the process of dividing up and redrawing districts to give your political party an advantage . so how exactly does someone go about protecting their own political party , and actually gerrymandering a district ? there are two successful practices . packing a district , and cracking a district . packing is the process of drawing district lines and packing in your opponents like cattle , into as few districts as possible . if more districts equals more votes , the fewer the districts there are , the fewer votes the opposition party will get . packing , then , decreases the opponent 's voter strength and influence . cracking is the opposite : taking one district and cracking it into several pieces . this is usually done in districts where your opponent has many supporters . cracking spreads these supporters out among many districts , denying your opponent a lot of votes . when you have a large number of people who would generally vote for one type of party , those folks are known as a voting bloc . cracking is a way to break that all up . so when would a party choose to pack their opponent 's districts rather than crack them ? well , that really depends on what the party needs . to dilute your opponent 's voters , you could pack them into one district and leave the surrounding districts filled with voters of your own party . or , if you and your party are in power when it 's time to redraw district lines , you could redraw districts and crack up a powerful district and spread your opponent 's voters out across several neighboring districts . so , governor gerry in 1812 wanted to gain an advantage for his party , and redrew district lines in his state in such a crazy way we have a whole new word and way of thinking about how political parties can gain advantages over their opponents . politicians think of creative ways to draw districts every few years . so the next time an election comes around , and politicians ask people to vote , be sure to look up the shape of your district and the districts that surround it . how wide does your district stretch across your state ? are all of the districts in your state relatively the same shape ? how many other districts does your district touch ? but always be sure to ask yourself , does my district look like a salamander ?
|
translator : tom carter reviewer : bedirhan cinar most people have heard the word `` gerrymandering '' once or twice , probably during a presidential election . what exactly is gerrymandering ? essentially , it 's the process of giving one political party an advantage over another political party by redrawing district lines .
|
what exactly is gerrymandering ?
|
so how many of you have ever been in a cave before ? okay , a few of you . when you think of a cave , most of you think of a tunnel going through solid rock . in fact , that 's how most caves are . around this half of the country , most of your caves are made of limestone . back where i 'm from , most of our caves are made from lava rock because we have a lot of volcanoes out there . but the caves i want to share with you today are made completely of ice , specifically glacier ice as formed in the side of the tallest mountain in the state of oregon called mount hood . now , mount hood 's only one hour 's drive from portland , the largest city in oregon where over two million people live . now , the most exciting thing for a cave explorer is to find a new cave and be the first human to ever go into it . the second most exciting thing for a cave explorer is to be the first one to make a map of a cave . now , these days , with so many people hiking around , it 's pretty hard to find a new cave , so you can imagine how excited we were to find three new caves within sight of oregon 's largest city and realize that they have never been explored or mapped before . it was kind of like being an astronaut because we were getting to see things and go places that no one had ever seen or gone before . so , what is a glacier ? well , those of you that have ever seen or touched snow , you know that it 's really light because it 's just a bunch of tiny ice crystals clumped together and it 's mostly air . if you squish a handful of snow to make a snowball , it gets really small , hard , and dense . well , in a mountain like hood where it snows over twenty feet a year , it crushes the air out of it and gradually forms it into hard , blue ice . now , each year more and more ice stacks up on top of it and eventually gets so heavy that it starts to slide down the mountain under its own weight , forming a slow-moving river of ice . when an ice pack like that starts to move , we call it a glacier and we give it a name . the name of the glacier these caves were formed is the sandy glacier . now , each year as new snow lands on the glacier , it melts in the summer sun , and it forms little rivers of water on the flow along the ice and they start to melt and bore their way down through the glacier , forming big networks of caves , sometimes going all the way down to the underlying bedrock . now , the crazy thing about glacier caves is that each year new tunnels form , different waterfalls pop up or move around from place to place inside the cave . warm water from the top of the ice is boring its way down , and warm air from below the mountain actually rises up , gets into the cave , and melts the ceilings back taller and taller . but the weirdest thing about glacier caves is that the entire cave is moving because it 's formed inside a block of ice the size of a small city that 's slowly sliding down the mountain . now , this is brent mcgregor , my cave exploration partner . he and i have both been exploring caves a long time and we 've been climbing mountains a long time , but neither of us have ever really explored a glacier cave before . back in 2011 , brent saw a youtube video of a couple of hikers that stumbled across the entrance to one of these caves . there were no gps coordinates for it , and all we knew was that it was somewhere out on the sandy glacier . so , in july of that year , we went out on the glacier , and we found a big crack in the ice . we had to build snow and ice anchors , so we could tie off ropes and repel down into the hole . this is me looking into the entrance crevasse . at the end of this hole , we found a huge tunnel going right up the mountain underneath thousands of tons of glacier ice . we followed this cave back for about a half mile until it came to an end . and then with the help of our survey tools , we made a three-dimensional map of the cave on our way back out . so , how do you map a cave ? well , cave maps are n't like trail maps or road maps because they have pits and holes going to overlapping levels . to make a cave map , you have to set up survey stations every few feet inside the cave , and you use a laser to measure the distance between those stations . and you use a compass and an inclinometer to measure the direction the cave is headed and measure the slope of the floor and the ceilings . now , those of you taking trigonometry , that particular type of math is very useful for making maps like this because it allows you to measure heights and distances without actually having to go there . in fact , the more i mapped and studied caves , the more useful i found all that math that i originally hated in school to be . so , when you 're done surveying , you take all this data , you punch it into the computer , and you find someone that can draw really well , and you have them draft up a map that looks something like this . and it will show you both a bird 's eye view of the passage as well as a profile view of the passage , kind of like an ant farm view . we named this cave snow dragon cave because it was like a big dragon sleeping under the snow . now , later this summer as more snow melted off the glacier , we found more caves , and we realized they were all connected . not long after we mapped snow dragon , brent discovered this new cave not very far away . the inside of it was coated with ice so we had to wear big spikes in our feet called crampons , so we could walk around without slipping . this cave was amazing ! the ice in the ceiling was glowing blue and green because the sunlight from far above was shining through the ice and lighting it all up . now , we could n't understand why this cave was so much colder than snow dragon until we got to the end , and we found out why . there was a huge pit or shaft called a moulin going a 130 feet straight up to the surface of the glacier . cold air from the top of the mountain was flowing down this hole , blasting through the cave , freezing everything inside of it . and we were so excited about finding this new pit , we actually came back in january the following year so we could be the first ones to explore it . it was so cold outside , we actually had to sleep inside the cave . here 's our camp on the left side of this entrance room . the next morning we climbed out of the cave and hiked all the way to the top of the glacier where we finally rigged and repelled this pit for the very first time . brent named this cave pure imagination , i think , because the beautiful sights we saw in there were beyond what we could have ever imagined . so , besides really cool ice , what else is inside these caves ? well , not too much lives in them because they 're so cold , and the entrance is actually covered up with snow for about eight months of the year , but there are some really cool things in there . there 's weird bacteria living in the water that actually eat and digest rocks to make their own food to live under this ice . in fact , this past summer scientists collected samples of water and ice specifically to see if things called extremophiles , tiny lifeforms that have evolved to live in a completely hostile conditions , might be living under the ice , kind of like what they hope to find in the polar ice caps of mars some day . another really cool thing is that as seeds and birds land on the surface of the glacier and die , they get buried in the snow and gradually become part of the glacier , sinking deeper and deeper into the ice . as these caves form and melt their way up into the ice , they make these artifacts rain down from the ceiling and fall into the cave floor where we end up finding them . for example , this is a nodal first seed we found . it 's been frozen in ice for over a hundred years , and it 's just now starting to sprout . this mallard duck feather was found over 1800 feet in the back of snow dragon cave . this duck died on the surface of the glacier long , long ago , and its feathers have finally made it down through over a hundred feet of ice before falling inside the cave . and this beautiful quartz crystal was also found in the back of snow dragon . even now brent and i find it hard to believe that all these discoveries were essentially in our own backyard , hidden away just waiting to be found . like i said earlier , the idea of discovery in this busy world we live in kind of seems like something you can only do with space travel now , but that 's not true . every year new caves get discovered that no one has ever been in before . so , it 's actually not too late for one of you to become a discoverer yourself . you just have to be willing to look and go where people do n't often go and focus your eyes and your mind to recognize the discovery when you see it because it might be in your own backyard . thank you very much .
|
when you think of a cave , most of you think of a tunnel going through solid rock . in fact , that 's how most caves are . around this half of the country , most of your caves are made of limestone . back where i 'm from , most of our caves are made from lava rock because we have a lot of volcanoes out there .
|
in and around new orleans , louisiana , most of the caves are made of ________ .
|
translator : andrea mcdonough reviewer : bedirhan cinar so as an astronomer , when i look at the sky with other people , they always ask me , `` what is your favorite place in the universe ? what is your favorite galaxy ? what is your favorite planet ? '' my answer is earth . that 's right . this is a very special place , even for an astronomer . we look at a lot of places , but there 's only one that we know of in the whole universe that we can live on . it 's an amazing planet , there is an amazing number of things happening , some of them , you are hearing about it today . that 's the only place in the universe where we know that there is life , so that makes it extremely special . what i 'm going to talk to you about is this great adventure in astronomy that is happening where we are actually actively looking for other places like this . it 's impossible to imagine the number of possibilities , what happens on those other planets that can be habitable . so that 's what i 'm going to tell you about . so , the first thing we have to think of is , well , what makes a planet habitable ? and , the easiest thing to do is to look at our own solar system . we have multiple examples . the first thing we learn is that size matters . we ca n't have a planet that 's too small or too big . if we look at a planet that is too small , it does n't have an atmosphere . the moon , technically not a planet , but a good example for this , is too small , it does n't hold an atmosphere . jupiter - very , very big - and it actually is mostly composed of gas , it has no surface you can stand on . the earth is just right . the second thing that we learned is that the planet has to be at the right distance from its star . if the planet is too close to its star , it 's too hot . that 's the case for venus . here i have a picture that was taken by a spacecraft that landed on venus , and the surface , although it 's rocky and quite familiar to us compared to earth , it 's really too hot . at the opposite end , if a planet is too far from the star , it is too cold . that 's the case for mars . so , we need to look for planets that are at the right distance from their star and also of the right size . so , one other thing , you know , you might think , `` oh , this is really hard because the planet has to be just right . it only happened once in our solar system . '' but when you look at the sky at night , and here 's a video that i took actually from hawaii , a dark place where you can see a lot of stars , the first thing you notice is that there are a lot of stars . so , the odds are in our favor , even if a small fraction of the stars have habitable planets . there are a lot of stars . on a moonless night , in a dark site , if you count the stars in the sky and you count five stars per second , it would take you 15 minutes to count all of the stars in the sky . that is a tiny fraction of the stars in our galaxy . if you count all the stars in our galaxy , and you also count at five stars per second , it would take you more than 1,000 years to count all the stars in our galaxy . and then , if you manage to count the galaxies in the universe , if you count five galaxies per second , it would take you also more than 1,000 years to count all of the galaxies in the universe . so the numbers are just astronomical , there 's a lot of opportunities for exoplanets . there has to be a large number of exoplanets along which there are , on which there could be life . so this is very exciting . so let 's imagine that maybe only 1 in 100 stars has the right kind of planet , and i think this is pessimistic . if you could visit one of those planets per second , it 'll take you sixty years to actually visit all of them in our galaxy alone . that 's , i think , one second is not enough to study them . so , there 's a few hundred of us in this room . if we divided the task and each of us basically took a couple of minutes to study each planet , it would take us a life time to do this . meet back again and tell those amazing stories of what we would have seen in maybe some ted senior event . so , why is it hard ? why do n't we have pictures of exoplanets with aliens on them ? well , here 's an example . this is a picture that was taken by the cassinni spacecraft as it was orbiting saturn . it 's actually behind saturn , so what you see is the sun that is blocked by saturn . and if you look very , in detail , if you have very sharp eyesight , you will see all of us . we 're all on that picture . here is where we are . um , so that 's what earth starts to look like when we look at it from far away . now , we have to do the same thing around other stars , and the planet is very close to the star . so this is zooming in to us . all of us are on that little dot at the time the picture was taken . so , what i work on is inventing optics , tricks to actually do this , to take images of planets around those other stars . this is my easiest coronagraph . we call this optic tricks , `` coronagraph '' . this is the easiest one i ever built . i just put my thumb in front of the sun and then you can see things around it . that 's what we 're trying to do , but we need to do it much better than what i did in this picture . and , there are two things we need to do : we need a much better eye , call them telescopes , and we need more fancy , clever ways to do it than putting a thumb . so as an example , one of the projects i work on is for the subaru telescope , which you can see here in this picture . it 's a very large telescope , so i replace my eye by a large telescope . and , the other thing that we do is the coronagraph is not just a stupid thumb , it 's this very complicated thing that 's shown in that picture that i would love to have time to tell you about . just to give you a sense for size , this arrow points to a door on the side of the telescope , and if you have very sharp eyes , you can see that there is a railing going around the telescope , so it 's a really big eye . so , i think the most exciting thing for me is actually to look at the night sky , to see all these stars and wonder , `` well , are there people on planets around those stars ? '' because there must be amazing things happening around those stars that we do n't know yet . during your life time , we will start to actually figure out those things . and the most exciting thing for me is to think about , maybe , beings on those stars looking back at our star and wondering the same thing . so i think the future will be extremely exciting because we are starting to figure out those things and amazing range of possibilities is , i think , even wider than our imagination . thank you .
|
it 's an amazing planet , there is an amazing number of things happening , some of them , you are hearing about it today . that 's the only place in the universe where we know that there is life , so that makes it extremely special . what i 'm going to talk to you about is this great adventure in astronomy that is happening where we are actually actively looking for other places like this .
|
where is the only place in the universe that we currently know life exists ?
|
it was a night like any other night , except here i was climbing the platonic peaks like romeo on a second date . ( ugh ) i was there for the dame . she had eyes like imaginary numbers and curves that went on forever . said she wanted to go home . said i could help . said the pay was good . did n't say anything about climbing a ... voice : `` who 's there ? '' manny brot : `` manny brot , private eye . '' voice : `` what are you doing here ? '' `` a pretty number sent me to find a stolen dingus . '' voice : `` well , to enter the cave , you must answer my riddles three . '' what was it with riddles , and why do they always come in threes ? `` is it an egg ? '' `` no . why would it be an egg ? '' `` it 's usually an egg . '' `` what can i hold in my hand , but has zero area ? '' `` is it a dodo egg ? '' `` it 's not an egg ! '' i took out the rock that had nearly brained me before and gave it a hard ponder . the size of the rising bump on my conk said to me that this thing had area , and a lot of it . but what if i carved out a triangle from this side here ? as any mook could see , this triangle had a quarter of the area of the full triangle . i did the same thing again with each of the smaller triangles . again , a quarter of the remaining area -- gone . and i just kept going . after an infinite number of cuts , i was satisfied that my triangle had zero area . a bounded shape with zero area . now , it 's not often that i surprise myself , but my own two mitts had created something crazy , and new . `` very good . ( ahem ) now , show me a shape with finite area , but an infinitely long perimeter . '' `` let me get this straight . if i want to make a snip in the border of this shape , smooth it out , and lay it on the ground ... `` `` it would go on for ... `` `` wait 'til i 'm through , and then you can talk . it would go on forever . '' `` are you through ? '' `` yeah . '' `` so show me that shape then . '' mmm ... i had n't been this stuck since the rubik 's cube fiasco of '58 . all the shapes i knew had perimeters . circles : 2πr . triangles : sum of their sides . what 's this ? an angle . an angle from heaven . what if i were to pinch each side , like so . a third of the way through , just so . and do it again , and again , and again . after each pinch , the perimeter got a third longer because where there had been three line segments , now there were four . as for the area , every pinch made more triangles , that 's true . but those triangles were getting smaller and smaller . you could say that the area was converging , approaching a fixed number , while the perimeter was just getting bigger and bigger , uncontrollably ballooning like an overindulgent birthday clown . after infinity pinches , flimflam , there it was : finite area , but infinite perimeter . now that is a piece of work . `` oh , you 're good . ( ahem ) riddle three : show me a picture that if i magnify it under my microscope , i 'll keep seeing the original picture , no matter how much i zoom in . '' `` you 're a strange little man . '' `` thank you . '' i was out of ideas , so i looked at my muse , my complex dora . voice : `` who 's the dame ? '' and then it hit me . `` she 's a heart breaker , my fractal femme fatale . will she do ? '' `` yes , she 'll do just fine . '' ( lightning ) it was dark , and at first i thought the cave was empty , but then i noticed : the box . the dame had played me like a triangle . she had told me she wanted to go home . ( lightning ) what she really wanted was to bring her home here . the fractals spread everywhere . most of them the same no matter how deep you looked at them , like dora 's mugshot . some had infinitely long perimeters , others were objects with no area or volume , all of them created through infinite repetition . so , you wanted to know what fractals are ? well , kid , they 're the stuff that dreams are made of . ( music )
|
the size of the rising bump on my conk said to me that this thing had area , and a lot of it . but what if i carved out a triangle from this side here ? as any mook could see , this triangle had a quarter of the area of the full triangle . i did the same thing again with each of the smaller triangles .
|
which of these is not true of sierpinski ’ s triangle ( the answer to the first riddle ) ?
|
thinking of getting a tattoo ? decorating your birthday suit would add another personal story to a history of tattoos stretching back at least 8000 years . tattooed mummies from around the world attest to the universality of body modification across the millennia , and to the fact that you really were stuck with it forever if your civilization never got around to inventing laser removal . a mummy from the chinchorro culture in pre-incan peru has a mustache tattooed on his upper lip . ötzi , mummified iceman of the alps , has patterned charcoal tats along his spine , behind his knee and around his ankles , which might be from an early sort of acupuncture . the mummy of amunet , a priestess in middle kingdom egypt , features tattoos thought to symbolize sexuality and fertility . even older than the mummies , figurines of seemingly tattooed people , and tools possibly used for tattooing date back tens of thousands of years . tattoos do n't have one historical origin point that we know of , but why do we english speakers call them all tattoos ? the word is an anglophonic modification of `` tatao , '' a polynesian word used in tahiti , where english captain james cook landed in 1769 and encountered heavily tattooed men and women . stories of cook 's findings and the tattoos his crew acquired cemented our usage of `` tattoo '' over previous words like `` scarring , '' `` painting , '' and `` staining , '' and sparked a craze in victorian english high society . we might think of victorians having victorian attitudes about such a risque thing , and you can find such sentiments , and even bans , on tattooing throughout history . but while publicly some brits looked down their noses at tattoos , behind closed doors and away from their noses , lots of people had them . reputedly , queen victoria had a tiger fighting a python , and tattoos became very popular among cook 's fellow soldiers , who used them to note their travels . you crossed the atlantic ? get an anchor . been south of the equator ? time for your turtle tat . but westerners sported tattoos long before meeting the samoans and maori of the south pacific . crusaders got the jerusalem cross so if they died in battle , they 'd get a christian burial . roman soldiers on hadrian 's wall had military tattoos and called the picts beyond it `` picts , '' for the pictures painted on them . there 's also a long tradition of people being tattooed unwillingly . greeks and romans tattooed slaves and mercenaries to discourage escape and desertion . criminals in japan were tattooed as such as far back as the 7th century . most infamously , the nazis tattooed numbers on the chest or arms of jews and other prisoners at the auschwitz concentration camp in order to identify stripped corpses . but tattoos forced on prisoners and outcasts can be redefined as people take ownership of that status or history . primo levi survived auschwitz and wore short sleeves to germany after the war to remind people of the crime his number represented . today , some holocaust survivors ' descendants have their relatives numbers ' tattooed on their arms . the torah has rules against tattoos , but what if you want to make indelible what you feel should never be forgotten ? and those criminals and outcasts of japan , where tattooing was eventually outlawed from the mid-19th century to just after world war ii , added decoration to their penal tattoos , with designs borrowed from woodblock prints , popular literature and mythical spirtual iconography . yakuza gangs viewed their outsider tattoos as signs of lifelong loyalty and courage . after all , they lasted forever and it really hurt to get them . for the maori , those tattoos were an accepted mainstream tradition . if you shied away from the excruciating chiseling in of your moko design , your unfinished tattoo marked your cowardice . today , unless you go the traditional route , your tattoo artist will probably use a tattoo machine based on the one patented by samuel o'reilly in 1891 , itself based on thomas edison 's stencil machine from 1876 . but with the incredibly broad history of tattoos giving you so many options , what are you going to get ? this is a bold-lined expression of who you are , or you want to appear to be . as the naturalist aboard cook 's ship said of the tataoed tahitians , `` everyone is marked , thus in different parts of his body , according maybe to his humor or different circumstances of his life . '' maybe your particular humor and circumstances suggest getting a symbol of cultural heritage , a sign of spirituality , sexual energy , or good old-fashioned avant-garde defiance . a reminder of a great accomplishment , or of how you think it would look cool if hulk hogan rode a rhino . it 's your expression , your body , so it 's your call . just two rules : you have to find a tattooist who wo n't be ashamed to draw your idea , and when in doubt , you can never go wrong with `` mom . ''
|
thinking of getting a tattoo ? decorating your birthday suit would add another personal story to a history of tattoos stretching back at least 8000 years .
|
how might an english person have referred to a tattoo before the introduction of the word tattoo ?
|
how do you know what 's happening in your world ? the amount of information just a click away may be limitless , but the time and energy we have to absorb and evaluate it is not . all the information in the world wo n't be very useful unless you know how to read the news . to your grandparents , parents , or even older siblings , this idea would have sounded strange . only a few decades ago , news was broad-based . your choices were limited to a couple of general interest magazines and newspaper of record , and three or four tv networks where trusted newscasters delivered the day 's news at the same reliable time every evening . but the problems with this system soon became apparent as mass media spread . while it was known that authoritarian countries controlled and censored information , a series of scandals showed that democratic governments were also misleading the public , often with media cooperation . revelations of covert wars , secret assassinations , and political corruption undermined public faith in official narratives presented by mainstream sources . this breakdown of trust in media gatekeepers lead to alternative newspapers , radio shows , and cable news competing with the major outlets and covering events from various perspectives . more recently , the internet has multiplied the amount of information and viewpoints , with social media , blogs , and online video turning every citizen into a potential reporter . but if everyone is a reporter , nobody is , and different sources may disagree , not only opinions , but on the facts themselves . so how do you get the truth , or something close ? one of the best ways is to get the original news unfiltered by middlemen . instead of articles interpreting a scientific study or a politician 's speech , you can often find the actual material and judge for yourself . for current events , follow reporters on social media . during major events , such as the arab spring or the ukrainian protests , newscasters and bloggers have posted updates and recordings from the midst of the chaos . though many of these later appear in articles or broadcasts , keep in mind that these polished versions often combine the voice of the person who was there with the input of editors who were n't . at the same time , the more chaotic the story , the less you should try to follow it in real time . in events like terrorist attacks and natural disasters , today 's media attempts continuous coverage even when no reliable new information is available , sometimes leading to incorrect information or false accusations of innocent people . it 's easy to be anxious in such events , but try checking for the latest information at several points in the day , rather than every few minutes , allowing time for complete details to emerge and false reports to be refuted . while good journalism aims for objectivity , media bias is often unavoidable . when you ca n't get the direct story , read coverage in multiple outlets which employ different reporters and interview different experts . tuning in to various sources and noting the differences lets you put the pieces together for a more complete picture . it 's also crucial to separate fact from opinion . words like think , likely , or probably mean that the outlet is being careful or , worse , taking a guess . and watch out for reports that rely on anonymous sources . these could be people who have little connection to the story , or have an interest in influencing coverage , their anonymity making them unaccountable for the information they provide . finally , and most importantly , try to verify news before spreading it . while social media has enabled the truth to reach us faster , it 's also allowed rumors to spread before they can be verified and falsehoods to survive long after they 've been refuted . so , before you share that unbelievable or outrageous news item , do a web search to find any additional information or context you might have missed and what others are saying about it . today , we are more free than ever from the old media gatekeepers who used to control the flow of information . but with freedom comes responsibility : the responsibility to curate our own experience and ensure that this flow does not become a flood , leaving us less informed than before we took the plunge .
|
to your grandparents , parents , or even older siblings , this idea would have sounded strange . only a few decades ago , news was broad-based . your choices were limited to a couple of general interest magazines and newspaper of record , and three or four tv networks where trusted newscasters delivered the day 's news at the same reliable time every evening .
|
so-called “ citizen journalism ” has exploded as smartphones , glasses-based cameras , and other tools make it easier for average people to report breaking news . what are some of the positives and negatives with citizen journalism ?
|
translator : andrea mcdonough reviewer : bedirhan cinar i like to think of life science as one big pyramid . let 's call the pyramid , `` biological organization '' . let 's work our way from very small and specific concepts to very large and complex topics . so let 's start at the tip of the pyramid , with something so small , it ca n't be seen by the human eye , a single cell . a cell by itself is the most basic component of life . a single cell , which is capable of living on its own , is called a unicellular organism , organisms like bacteria or protists . these organisms are everywhere you look , you just ca n't see them . but , when cells join together , with more than one cell like itself to perform a similar function , it 's no longer a unicellular organism . it 's then called a tissue . no , not that kind of tissue . there are four types of tissues found in the human body : connective , muscle , nervous , and epithelial . bone tissue is a type of connective tissue and it 's not flimsy like a kleenex at all . blood is also an example of the same cells working together to perform the same job , but it 's a liquid , again , not like a kleenex at all . no matter what the consistency is , a tissue is a group of the same cells , working together to perform a similar function . any time there are different tissues working together , we then call it an organ . that 's the next level of the pyramid . animals are n't the only ones with organs ; plants have organs too . when we find multiple different organs working together to perform the same job , we then call it an organ system . take the digestive system , for example . it 's made up of a mouth , esophagus , stomach , pancreas , liver , gall bladder , small intestine , and large intestine , also known as your colon . although each individual organ in this organ system does a very different job , together , these organs work to achieve the one goal of taking all the nutrients out of the food we eat and getting rid of what we do n't need . an organ system , by definition , can only do one job , like get the nutrients from our food , send and receive electrical signals , or exchange oxygen for carbon dioxide . regardless of their individual function , all organ systems rely on one another to do the vital jobs which they ca n't do themselves . if one organ system does n't work , the others will shut down , too . an organism is a complicated , living thing , which requires the proper functioning of multiple organ systems to maintain stability . this stability is called homeostasis . when all organ systems are working together and maintaining homeostasis , then it results in a happy , living organism . organisms are incredibly diverse and can be as simple as a bacteria or as complex as you . when a group of the same organisms , also known as a species , live together in the same environment , we then call it a population . often there are several populations all living in one environment . that is what we call a community . each time you look out the window , you 're seeing a community . when we look at multiple communities , along with how all of the organisms interact with the physical environment , then we refer to it as an ecosystem . when you look at all the ecosystems of earth together , you 're looking at the earth . the earth is a big , round circle of life . that 's why we call it a biosphere - bio , meaning life and sphere , meaning circle . and there you go ! when you break it down to each level , a very complex concept and phrase becomes easy to understand . all life starts with a single cell . when cells join together , they are called a tissue . a group of different tissues are called an organ , and a group of different organs are an organ system . a group of organ systems working together make up an organism , and a group of the same organisms are a population . combining several different populations together give us a community . and several different communities in a large area is an ecosystem . and every ecosystem together makes up our biosphere . and that , my friends , is biological organization , the pyramid of life .
|
translator : andrea mcdonough reviewer : bedirhan cinar i like to think of life science as one big pyramid . let 's call the pyramid , `` biological organization '' . let 's work our way from very small and specific concepts to very large and complex topics .
|
biological organization is a way to organize :
|
it 's easy to forget how vast and deep the ocean really is . about 60 % of it is actually a cold and dark region known as the deep ocean . and it reaches down to 11,000 meters . yet , this remote zone is also one of the greatest habitats on earth , harboring a huge diversity of life , from giant squids and goblin sharks to minuscule animals smaller than a millimeter . how do so many species thrive in this underwater world ? over the decades , intrepid scientists have ventured there to find out . traveling down through the water column , pressure increases and light begins to wane . at 200 meters , photosynthesis stops and temperature decreases from surface temperatures by up to 20 degrees celsius . by 1000 meters , normal sunlight has disappeared altogether . without light , life as we know it seems impossible . that 's why in 1844 , the naturalist edward forbes wrote his azoic theory , azoic , meaning without animals . forbes was sure that nothing could survive below 600 meters on account of the lack of light . of course , the discovery of deep-sea species proved him wrong . what forbes failed to take into account is something called marine snow , which sounds much nicer than it is . marine snow is basically organic matter , things like particles of dead algae , plants , and animals , drifting down into the depths and acting as food for deep-sea animals . largely thanks to that , abundant life forms exist in the darkness , adapting to a harsh reality where only the weird and wonderful can survive . fish with cavernous mouths , spiky teeth jutting from their jaws , and lamp-like structures protruding from their heads , like the anglerfish which entices prey with its misleading glow . several sea creatures have perfected this lightning technique known as bioluminescence , using it to lure prey , distract predators , or attract mates . some creatures use it for camoflauge . in parts of the water column where only faint blue light filters through , animals bioluminesce to match the glow . predators or prey looking up from below are deceived by this camoflauge , unable to see the creatures silhouette . such otherworldly adaptations also arise from the need to locate and snatch up food before it drifts away . some sea animals , like jellyfish , comb jellies and salps can migrate between depths partially because their 90 % water consistency allows them to withstand immense pressure . but they 're the exception . most deep-sea creatures are confined to a narrow range in the water column where nutrients are scarce since the food drifting downwards from the surface rapidly sinks to the sea floor . plunging all the way down , we find more exotic creatures . some take on dwarfism , a trait that transforms them into miniature versions of animals we see closer to the surface . it 's thought that reduced food availability causes the shrinkage . only a tiny fraction of the food produced at the surface reaches the sea floor , so being small gives animals a low energy requirement and an adaptive advantage . and yet , the sea is also the land of giants . here , gargantuan squids can reach 18 meters long . isopods scuttle around the sea floor like enormous wood lice . there are long-limbed japanese spider crabs , and oarfish , whose bodies stretch to 15 meters . this trait is known as gigantism , and it 's something of a mystery . it 's thought that high oxygen levels may drive extreme growth in some species , while the colder temperatures promote longer life spans , giving animals the opportunity to grow massive . many of these exotic sea beasts will never experience sunlight . some will venture up through the water column to feed , and a few will actually break the waves , reminding us at the surface about the incredible survival skills of the ocean 's deepest inhabitants . humans still have an astounding 95 % of the ocean left to explore . so those depths remain a great mystery . what other untold wonders lie far below , and which ones will we discover next ?
|
what forbes failed to take into account is something called marine snow , which sounds much nicer than it is . marine snow is basically organic matter , things like particles of dead algae , plants , and animals , drifting down into the depths and acting as food for deep-sea animals . largely thanks to that , abundant life forms exist in the darkness , adapting to a harsh reality where only the weird and wonderful can survive .
|
which adaptation is commonly observed in deep sea animals ?
|
translator : andrea mcdonough reviewer : bedirhan cinar the oval office , inauguration day , rose garden signings , and secret service agents with dark sunglasses and cool wrist radios . for a moment , forget all of it . toss out everything you know about the president . now , start over . what would you do if you had to invent the president ? that was the question facing the 55 men who got together in secret to draw up the plans for a new american government in the summer of 1787 in philadelphia , in the same place where the declaration of independence had been written eleven years earlier . declaring independence had been risky business , demanding ferocious courage that put lives and fortunes in jeopardy . but , inventing a new government was no field day either , especially when it 's summer and you 're in scratchy suits , and the windows are closed because you do n't want anybody to hear what you are saying , and the air conditioning does n't work because it wo n't be invented for nearly 200 years . and , when you do n't agree on things , it gets even hotter . for the framers , the question they argued over most while writing the constitution and creating three branches of government had to do with the executive department . one man or three to do the job ? how long should he serve ? what would he really do ? who would pick him ? how to get rid of him if he 's doing a bad job or he 's a crook ? and , of course , they all meant him , and he would be a white man . the idea of a woman or an african american , for instance , holding this high office was not a glimmer in their eyes . but the framers knew they needed someone who could take charge , especially in a crisis , like an invasion or a rebellion , or negotiating treaties . congress was not very good at making such important decisions without debates and delays . but the framers thought america needed a man who was decisive and could act quickly . they called it energy and dispatch . one thing they were dead-set against : there would be no king . they had fought a war against a country with a monarch and were afraid that one man with unchecked powers , in charge of an army , could take over the country . instead , they settled on a president and laid out his powers in article 2 of the constitution . but who would choose him ? not the people , they were too liable to be misled as one framer worried . not the legislature , that would lead to cabal and factions . got it : electors , wise , informed men who have time to make a good decision . and if they did n't produce a winner , then the decision would go to one of the other branches of government , the congress . the house of representatives would step in and make the choice , which they did in 1801 and 1825 . in the long , hot summer of 1787 , compromises were made to invent the presidency , like counting slaves as 3/5 of a person , giving the president command of the army but congress the power to declare war , and unlimited four-year terms . since then , some of those compromises have been amended and the men in office have sometimes been too strong or too weak . but , if you could start from scratch , how would you redesign the oval office ?
|
not the legislature , that would lead to cabal and factions . got it : electors , wise , informed men who have time to make a good decision . and if they did n't produce a winner , then the decision would go to one of the other branches of government , the congress .
|
the men who wrote the constitution are often referred to as the :
|
what lights up the screen that you 're looking at right now ? trace back the battery chargers and power cords and you 'll end up at an electrical outlet , providing easy , safe access to reliable electricity . but beyond that outlet , the picture gets messier . it takes a lot of fuel to heat our homes , preserve our food , and our power our gadgets around the clock . and for 40 % of the world , that fuel is cheap , plentiful , and it 's called coal . but coal also releases pollutants into the air , like sulfur dioxide , nitrogen oxides , soot , and toxic metals , like mercury . these cause environmental damage , like acid rain , and serious health problems . in fact , in 1952 , coal burning caused such heavy smog in london that pedestrians could n't even see their feet , and thousands of people died from ill health . since then , many countries have deployed technology to remove most of these pollutants before they reach the air . but now we have a new air pollution problem on our hands , one that does n't show up in a cloud of dark smog , but in rising seas , floods , and heat waves . it 's global climate change , and again , the main culprit is coal . it 's responsible for 44 % of global carbon dioxide emissions , which trap the sun 's heat in the earth 's atmosphere , instead of letting it escape . so now the question is how do we remove that bad stuff as well ? that 's the idea behind cleaner coal . creating cleaner coal is really about trying to contain its ill effects with the help of special technologies that make the end product more acceptable . just like the most intriguing superheroes often have their own dark powers to overcome , so we can try and keep coal 's negative forces in check . but why do n't we just exterminate coal if it takes that much effort to clean it up ? simply , coal is extremely valuable to us , and it 's easy to come by . compressed underground for ages , coal holds chemical energy from plants that were fed from by the sun hundreds of millions of years ago , long before humans evolved . that makes coal energy dense , meaning it can be burned 'round the clock . it 's also cheap , if you ignore the pollution costs , and should last us through the end of the 21st century . we 've already got all the infrastructure in place for harnessing its power , and globally , although countries are making a move towards energy from cleaner and more renewable sources , there 's no sign yet that coal use is slowing down . in fact , as of 2012 , over 1000 new coal plants have been proposed , mostly in china and india . since for the time being coal is here to stay , experts say that if we want to reduce its emissions ' impact on the atmosphere , and slow down climate change , we 'll have to think of creative ways of reducing coal 's destructive power . to do that , we need to strip it of its foul forces , all that toxic carbon dioxide that causes havoc in the atmosphere . then , we need to store the co2 somewhere else . this mission is called carbon capture and sequestration , or ccs . and as if carbon dioxide were some evil genie we did n't want to escape , once it has been separated from coal , we 've devised ways to banish it underground . we can do this by injecting it deep into the earth , or by placing it deep under the ocean 's surface . stripping away coal 's negative elements can happen in three ways . first , and most commonly , as coal burns , the exhaust gas can be mixed with a compound called monoethanolamine . like a forceful power-stripping magnet , this compound bonds to the co2 , yanking it out of the gas stream so it can be stored separately underground . another method is to relieve coal of its co2 before it even has a chance to be released as exhaust . in this process , steam and oxygen swoop in to the rescue to convert coal into a special product called syngas , made up of carbon monoxide and hydrogen and some co2 . zap that with some water vapor , and the carbon monoxide gets converted into carbon dioxide , which can be isolated . the leftover hydrogen gas is then used as energy to generate electricity , so there 's an added bonus . a third technique exposes coal to pure oxygen , instead of burning it in air . this creates exhaust gas with higher concentrations of carbon dioxide , which makes it easy to isolate and to banish to the chasms below . all this can reduce emissions at a power plant by up to 90 % , but as with any superhero struggling with their destructive powers , it takes a lot of effort to switch over from the dark side . so these positive pollution-busting forces , although they 're available , have barely been used in commercial power plants because they cost a lot . but ultimately , the bigger problem is that in most parts of the world , it 's still too easy and much cheaper to keep emitting carbon dioxide , and that makes it tempting to completely ignore coal 's dark side . in this case , the most powerful force for good is regulation , the rules that can restrict the amount of carbon dioxide emitted from power plants , and make energy companies around the world wary of what they put into the air . until then , every time you turn on a screen or flick a light switch , coal is lurking in the background , carrying its dark powers with it wherever it goes .
|
that makes coal energy dense , meaning it can be burned 'round the clock . it 's also cheap , if you ignore the pollution costs , and should last us through the end of the 21st century . we 've already got all the infrastructure in place for harnessing its power , and globally , although countries are making a move towards energy from cleaner and more renewable sources , there 's no sign yet that coal use is slowing down .
|
why do you think it ’ s a problem to ignore the cost of pollution when we make assessments of how much coal costs us ?
|
in the early 1960s , dick fosbury tried his hand at almost every sport , but never excelled at anything , until , at the age of 16 , he turned to the high jump . but when he could n't compete against the strong athletes at his college using the standard high jump techniques of the time , fosbury tried to jump a different way : backwards . instead of jumping with his face towards the bar , bringing each leg over in the traditional straddle method , he jumped with his back towards the bar . fosbury improved his record by over half a foot , and left his coaches amazed by this strange new style of high jumping . during the next few years , fosbury perfected his high jump style , won the u.s. national trials , and assured his place in the 1968 olympics in mexico . in the olympic games , fosbury amazed the world with his new technique , winning a gold metal with an olympic record leap of 2.24 meters . by the next olympic games , almost all of the competing of high jumpers had adopted what came to be known as the fosbury flop . what 's the secret behind the technique ? it lies in a physics concept called the center of mass . for every object , we can locate the average position of all of its mass by taking into account how the mass is spread around the object . for instance , the center of mass of a flat , rectangular object of uniform density will be in the intersection of both diagonals , in equal distance from each corner . we can find the center of mass for other objects by similar calculations , or by finding the object 's balancing point , which lies right underneath its center of mass . try balancing a broom by holding it and slowly bringing your hands together until they meet . this balancing point lies right underneath the broom 's center of mass . we humans also have a center of mass . when most people stand up , their center of mass is around the belly , but what happens to your center of mass when you lift your hands in the air ? your center of mass moves upwards . it moves all the time as you move through the day , based on how your body is positioned . it can even move outside of your body . when you bend forward , your center of mass is located below your bent belly in a place where there is no mass at all . weird to think about , but that 's the average position of all your mass . many objects ' center of mass are outside their bodies . think of doughnuts or boomerangs . now look at the fosbury flop , and follow the position of the center of mass of the jumper . the jumper runs very fast , so he can divert his horizontal velocity to vertical velocity , and jumps . wait for it ... there . look at the jumper 's center of mass as his body bends backward . it 's below the bar . that is the secret behind the jump . with the old , pre-fosbury techniques , the jumper had to apply enough force to lift his center of mass above the bar by a few inches in order to clear it . the fosbury flopper does n't have to do that . the genius of the fosbury flop is that the jumper can apply the same amount of force , but raise his body much higher than before . that means he can raise the bar so high that even when his center of mass ca n't go any higher , his arching body can . fosbury 's technique brought the high jump to new heights by splitting the jumper 's body away from his center of mass , giving it that much more room to clear higher and higher bars . so the fosbury flop may be sports history 's only great leap forward , that is also a great leap backward .
|
weird to think about , but that 's the average position of all your mass . many objects ' center of mass are outside their bodies . think of doughnuts or boomerangs .
|
which of the following objects ' center of mass is located outside of its body ?
|
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 .
|
choose the three sources of power you think are most valuable . explain your choices .
|
since the dawn of humanity , an estimated 100.8 billion people have lived and died , a number that increases by about .8 % of the world 's population each year . what happens to all of those people 's bodies after they die and will the planet eventually run out of burial space ? when a person 's heart stops beating , the body passes through several stages before it begins decomposing . within minutes after death , the blood begins settling in the lower-most parts of the body . usually eight to twelve hours later , the skin in those areas is discolored by livor mortis , or post-mortem stain . and while at the moment of death the body 's muscles relax completely in a condition called primary flaccidity , they stiffen about two to six hours later in what 's known as rigor mortis . this stiffening spreads through the muscles , and its speed can be affected by age , gender , and the surrounding environment . the body also changes temperature , usually cooling off to match its environment . next comes decomposition , the process by which bacteria and insects break apart the body . many factors affect the rate of decomposition . there is , however , a basic guide of the effect of the environment on decompositon called casper 's law . it says that if all other factors are equal , a body exposed to air decomposes twice as fast as one immersed in water and eight times as fast as one buried in earth . soil acidity also greatly affects bone preservation . high-acidity soils with a ph of less than 5.3 will rapidly decompose bone , whereas in a neutral or basic soil with a ph of 7 or more , a skeleton can remain in relatively good condition for centuries . different cultures throughout history have developed unique approaches to burials . as far back as the first neanderthal burials , death was accompanied by rituals , like the positioning , coloring , or decorating of corpses . traditional christian burials decorate the body in dress , while in traditional islam , a body is wrapped in a piece of ritual fabric with the face oriented toward mecca . traditional hindus ceremonially burn the body , and zoroastrians , followers of one of the oldest monotheistic religions , traditionally place bodies atop a tower to expose them to the sun and scavenging birds.` before the industrial revolution , burials were simple and accessible . these days , with suitable burial land running out in high-population areas , purchasing private gravesites can be costly , and many people ca n't afford simple burials . even cremation , the second most common burial practice in the world , comes with a high cost . as for the question of running out of space , the issue is n't so much about total land in the world as it is that large populations cluster together within cities . most of the big cities in the world may run out of suitable burial grounds within a century . for london , it 's even sooner . that may happen by 2035 . so are there alternatives to traditional burials that might help with the space issue ? in some countries , skyscraper cemeteries enable vertical burials . some options focus on the body 's relationship with the environment . promession , for example , freeze-dries and pulverizes the body , creating a powder that can turn into compost when mixed with oxygen and water . there are also green burials that use special materials , such as biodegradable caskets , urns that sprout trees , and burial suits that grow mushrooms . eternal reefs take that concept to the depths of the ocean using a mixture of ashes and cement to create marine habitats for sea life . death is an inevitable part of the human condition , but how we treat bodies and burials continues to evolve . we may each have different spiritual , religious , or practical approaches to dying , but the ever-increasing demand for burial space might give us a push to be creative about where our bodies go after the final stages of life .
|
within minutes after death , the blood begins settling in the lower-most parts of the body . usually eight to twelve hours later , the skin in those areas is discolored by livor mortis , or post-mortem stain . and while at the moment of death the body 's muscles relax completely in a condition called primary flaccidity , they stiffen about two to six hours later in what 's known as rigor mortis .
|
post mortem stain is called :
|
have you ever talked with a friend about a problem only to realize that he just does n't seem to grasp why the issue is so important to you ? have you ever presented an idea to a group and it 's met with utter confusion ? or maybe you 've been in an argument when the other person suddenly accuses you of not listening to what they 're saying at all ? what 's going on here ? the answer is miscommunication , and in some form or another , we 've all experienced it . it can lead to confusion , animosity , misunderstanding , or even crashing a multimillion dollar probe into the surface of mars . the fact is even when face-to-face with another person , in the very same room , and speaking the same language , human communication is incredibly complex . but the good news is that a basic understanding of what happens when we communicate can help us prevent miscommunication . for decades , researchers have asked , `` what happens when we communicate ? '' one interpretation , called the transmission model , views communication as a message that moves directly from one person to another , similar to someone tossing a ball and walking away . but in reality , this simplistic model does n't account for communication 's complexity . enter the transactional model , which acknowledges the many added challenges of communicating . with this model , it 's more accurate to think of communication between people as a game of catch . as we communicate our message , we receive feedback from the other party . through the transaction , we create meaning together . but from this exchange , further complications arise . it 's not like the star trek universe , where some characters can vulcan mind meld , fully sharing thoughts and feelings . as humans , we ca n't help but send and receive messages through our own subjective lenses . when communicating , one person expresses her interpretation of a message , and the person she 's communicating with hears his own interpretation of that message . our perceptual filters continually shift meanings and interpretations . remember that game of catch ? imagine it with a lump of clay . as each person touches it , they shape it to fit their own unique perceptions based on any number of variables , like knowledge or past experience , age , race , gender , ethnicity , religion , or family background . simultaneously , every person interprets the message they receive based on their relationship with the other person , and their unique understanding of the semantics and connotations of the exact words being used . they could also be distracted by other stimuli , such as traffic or a growling stomach . even emotion might cloud their understanding , and by adding more people into a conversation , each with their own subjectivities , the complexity of communication grows exponentially . so as the lump of clay goes back and forth from one person to another , reworked , reshaped , and always changing , it 's no wonder our messages sometimes turn into a mush of miscommunication . but , luckily , there are some simple practices that can help us all navigate our daily interactions for better communication . one : recognize that passive hearing and active listening are not the same . engage actively with the verbal and nonverbal feedback of others , and adjust your message to faciliate greater understanding . two : listen with your eyes and ears , as well as with your gut . remember that communication is more than just words . three : take time to understand as you try to be understood . in the rush to express ourselves , it 's easy to forget that communication is a two-way street . be open to what the other person might say . and finally , four : be aware of your personal perceptual filters . elements of your experience , including your culture , community , and family , influence how you see the world . say , `` this is how i see the problem , but how do you see it ? '' do n't assume that your perception is the objective truth . that 'll help you work toward sharing a dialogue with others to reach a common understanding together .
|
when communicating , one person expresses her interpretation of a message , and the person she 's communicating with hears his own interpretation of that message . our perceptual filters continually shift meanings and interpretations . remember that game of catch ?
|
which of the following influences our perceptual filters ?
|
in the biblical story of the tower of babel , all of humanity once spoke a single language until they suddenly split into many groups unable to understand each other . we do n't really know if such an original language ever existed , but we do know that the thousands of languages existing today can be traced back to a much smaller number . so how did we end up with so many ? in the early days of human migration , the world was much less populated . groups of people that shared a single language and culture often split into smaller tribes , going separate ways in search of fresh game and fertile land . as they migrated and settled in new places , they became isolated from one another and developed in different ways . centuries of living in different conditions , eating different food and encountering different neighbors turned similar dialects with varied pronunciation and vocabulary into radically different languages , continuing to divide as populations grew and spread out further . like genealogists , modern linguists try to map this process by tracing multiple languages back as far as they can to their common ancestor , or protolanguage . a group of all languages related in this way is called a language family , which can contain many branches and sub-families . so how do we determine whether languages are related in the first place ? similar sounding words do n't tell us much . they could be false cognates or just directly borrowed terms rather than derived from a common root . grammar and syntax are a more reliable guide , as well as basic vocabulary , such as pronouns , numbers or kinship terms , that 's less likely to be borrowed . by systematically comparing these features and looking for regular patterns of sound changes and correspondences between languages , linguists can determine relationships , trace specific steps in their evolution and even reconstruct earlier languages with no written records . linguistics can even reveal other important historical clues , such as determining the geographic origins and lifestyles of ancient peoples based on which of their words were native , and which were borrowed . there are two main problems linguists face when constructing these language family trees . one is that there is no clear way of deciding where the branches at the bottom should end , that is , which dialects should be considered separate languages or vice versa . chinese is classified as a single language , but its dialects vary to the point of being mutually unintelligible , while speakers of spanish and portuguese can often understand each other . languages actually spoken by living people do not exist in neatly divided categories , but tend to transition gradually , crossing borders and classifications . often the difference between languages and dialects is a matter of changing political and national considerations , rather than any linguistic features . this is why the answer to , `` how many languages are there ? '' can be anywhere between 3,000 and 8,000 , depending on who 's counting . the other problem is that the farther we move back in time towards the top of the tree , the less evidence we have about the languages there . the current division of major language families represents the limit at which relationships can be established with reasonable certainty , meaning that languages of different families are presumed not to be related on any level . but this may change . while many proposals for higher level relationships -- or super families -- are speculative , some have been widely accepted and others are being considered , especially for native languages with small speaker populations that have not been extensively studied . we may never be able to determine how language came about , or whether all human languages did in fact have a common ancestor scattered through the babel of migration . but the next time you hear a foreign language , pay attention . it may not be as foreign as you think .
|
as they migrated and settled in new places , they became isolated from one another and developed in different ways . centuries of living in different conditions , eating different food and encountering different neighbors turned similar dialects with varied pronunciation and vocabulary into radically different languages , continuing to divide as populations grew and spread out further . like genealogists , modern linguists try to map this process by tracing multiple languages back as far as they can to their common ancestor , or protolanguage .
|
what are some reasons that it ’ s impossible to give an exact number for how many different languages there are ?
|
imagine , for a second , a duck teaching a french class , a ping-pong match in orbit around a black hole , a dolphin balancing a pineapple . you probably have n't actually seen any of these things , but you could imagine them instantly . how does your brain produce an image of something you 've never seen ? that may not seem hard , but that 's only because we 're so used to doing it . it turns out that this is actually a complex problem that requires sophisticated coordination inside your brain . that 's because to create these new , weird images , your brain takes familiar pieces and assembles them in new ways , like a collage made from fragments of photos . the brain has to juggle a sea of thousands of electrical signals getting them all to their destination at precisely the right time . when you look at an object , thousands of neurons in your posterior cortex fire . these neurons encode various characteristics of the object : spiky , fruit , brown , green , and yellow . this synchronous firing strengthens the connections between that set of neurons , linking them together into what 's known as a neuronal ensemble , in this case the one for pineapple . in neuroscience , this is called the hebbian principle , neurons that fire together wire together . if you try to imagine a pineapple later , the whole ensemble will light up , assembling a complete mental image . dolphins are encoded by a different neuronal ensemble . in fact , every object that you 've seen is encoded by a neuronal ensemble associated with it , the neurons wired together by that synchronized firing . but this principle does n't explain the infinite number of objects that we can conjure up in our imaginations without ever seeing them . the neuronal ensemble for a dolphin balancing a pineapple does n't exist . so how come you can imagine it anyway ? one hypothesis , called the mental synthesis theory , says that , again , timing is key . if the neuronal ensembles for the dolphin and pineapple are activated at the same time , we can perceive the two separate objects as a single image . but something in your brain has to coordinate that firing . one plausible candidate is the prefrontal cortex , which is involved in all complex cognitive functions . prefrontal cortex neurons are connected to the posterior cortex by long , spindly cell extensions called neural fibers . the mental synthesis theory proposes that like a puppeteer pulling the strings , the prefrontal cortex neurons send electrical signals down these neural fibers to multiple ensembles in the posterior cortex . this activates them in unison . if the neuronal ensembles are turned on at the same time , you experience the composite image just as if you 'd actually seen it . this conscious purposeful synchronization of different neuronal ensembles by the prefrontal cortex is called mental synthesis . in order for mental sythesis to work , signals would have to arrive at both neuronal ensembles at the same time . the problem is that some neurons are much farther away from the prefrontal cortex than others . if the signals travel down both fibers at the same rate , they 'd arrive out of sync . you ca n't change the length of the connections , but your brain , especially as it develops in childhood , does have a way to change the conduction velocity . neural fibers are wrapped in a fatty substance called myelin . myelin is an insulator and speeds up the electrical signals zipping down the nerve fiber . some neural fibers have as many as 100 layers of myelin . others only have a few . and fibers with thicker layers of myelin can conduct signals 100 times faster or more than those with thinner ones . some scientists now think that this difference in myelination could be the key to uniform conduction time in the brain , and consequently , to our mental synthesis ability . a lot of this myelination happens in childhood , so from an early age , our vibrant imaginations may have a lot to do with building up brains whose carefully myelinated connections can craft creative symphonies throughout our lives .
|
this conscious purposeful synchronization of different neuronal ensembles by the prefrontal cortex is called mental synthesis . in order for mental sythesis to work , signals would have to arrive at both neuronal ensembles at the same time . the problem is that some neurons are much farther away from the prefrontal cortex than others .
|
in what tasks would you expect to see a deficit in a lobotomy patient ?
|
so copernicium , or copernicium as the discoverers would prefer it to be pronounced , is the latest name to go up on the periodic table and it is really very exciting because it is the first time in as many years that a new name has appeared . and not only has it appeared but quite excitingly , it has appeared with a bit of controversy - what should the symbol be ? the first suggestion was that it should be called , the symbol should be cp , capital c with little p and that has got really quite an argument inorganic chemists who use organic groups in their compounds got quite excited because cp is the symbol that is used for cyclopentadienyl ion which binds to all sorts of different metals and then it was discovered or realised that , many , many years ago , cp was used as an alternative symbol for element number 71 , lutetium , which in some countries we called cassiopeium . and i ’ ve looked in lots and lots of books that i have got at home and i can ’ t find one of them that uses this name , but the reason why it is important is because now more and more old papers , old books are being digitised on the internet , if you start searching for the symbol cp it will start throwing up old papers and cause confusion . so the decision has been made by the international union of pure and applied chemistry or the recommendation is that the symbol should be cn , capital c , little n. and i think that this is a very sensible suggestion because it is unlikely that it can be confused with cyanide which is capital c , capital n. and it is also nice for our chinese colleagues because cn is the domain name for chinese websites and i think most chemists will be very happy with that . the element itself was first made quite a few years ago , and it ’ s made like all these heavy elements by taking the nuclei of two atoms that are lighter and banging them together and if you are aiming for element 112 then you need to take 2 nuclei , which have atomic numbers which when you add them together come up to 112 , so in this case you take lead which is atomic number 82 and so to get from 82 to 112 you need to add 30 , so you accelerate zinc atoms which have atomic number of 30 towards these in a high speed accelerator and every so often , and quite rarely , these two nuclei fuse together to give you an element or an atom of element 112 . when you make the atom , it exists , for a short time which might be a thousandth of a second , or a few thousandths of a second or it might be as long as half a second or even a second . and then the nucleus of the atom starts to decay . now it doesn ’ t blow into parts which are just protons and neutrons in one great whoosh ! but instead it starts going down by steps , usually the atomic number changes by two units or one unit depending what sort of particle is ejected from the nucleus . so in the case of 112 , and i don ’ t know the details yet , it will decay . for example , the first step may be going from 112 to 110 then the second step may be just one unit to 109 , and then two down to 107 and so on . until you get to an element below the mass of uranium the mass of 92 - which is stable .
|
and not only has it appeared but quite excitingly , it has appeared with a bit of controversy - what should the symbol be ? the first suggestion was that it should be called , the symbol should be cp , capital c with little p and that has got really quite an argument inorganic chemists who use organic groups in their compounds got quite excited because cp is the symbol that is used for cyclopentadienyl ion which binds to all sorts of different metals and then it was discovered or realised that , many , many years ago , cp was used as an alternative symbol for element number 71 , lutetium , which in some countries we called cassiopeium . and i ’ ve looked in lots and lots of books that i have got at home and i can ’ t find one of them that uses this name , but the reason why it is important is because now more and more old papers , old books are being digitised on the internet , if you start searching for the symbol cp it will start throwing up old papers and cause confusion .
|
why was cn finally accepted instead of cp for the copernicium symbol ? what does cp mean in organic chemistry ?
|
a lone priestess walks towards an underground chamber . people line the streets to watch as she proclaims her innocence . it does n't matter . she 's already been judged and found guilty . the sentence ? live burial . the underground chamber contains a portion of bread , water , milk , and oil . she will have a lamp , a bed , and a blanket , but she wo n't emerge alive . at the threshold , the priestess pauses , claims her innocence one last time , then enters the chamber never to be seen again by the roman people . the priestess is one of rome 's six vestal virgins , each carefully selected as children from rome 's most aristocratic families . but now with her death , there are only five , and a new priestess must be chosen . the six-year-old licinia witnessed the spectacle , never suspecting that a few days later , she 'd be chosen as the next vestal virgin . her age , her patrician family lineage , and her apparent good health makes her the best candidate to serve the goddess vesta in the eyes of the romans . her parents are proud that their daughter 's been chosen . licinia is afraid , but she has no choice in the matter . she must serve the goddess for at least the next 30 years . for the first ten years of licinia 's service , she 's considered in training , learning how to be a vestal virgin . her most important duty is keeping vigil over the flame of vesta , the virgin goddess of the hearth . vesta does n't have a statue like other roman gods and goddesses . instead , she 's represented by the flame which burns day and night in her temple located next to the forum in the center of the city . like all vestal priestesses , licinia spends part of each day on shift , watching and tending to the flame . the flame represents two things . the first is the continuation of rome as a power in the world . the romans believed that if the flame goes out , the city 's in danger . the flame also symbolizes the continuing virginity of vesta 's priestesses . for the romans , a vestal 's virginity signaled not only her castitas , or modest spirit and body , but also her ritual purity . so licinia knows she must never let the flame go out . her life , the lives of her fellow vestals , and the safety of rome itself depends upon it . licinia learns to collect water each day from a nearby fountain to cleanse the temple . she learns the fasti , the calendar of sacred rituals and she watches while the senior priestesses conduct sacrifices . by the time licinia completes her training , she 's 16 years old . licinia understands that the way she must act is a reflection of the goddess she serves . when it 's her turn to collect the water , she keeps her eyes lowered to the ground . when she performs sacrifices , she focuses intently on the task . licinia directs her energy towards being the best priestess she can be . she 's worried that someday the state will claim her life for its own purposes to protect itself from danger . licinia could be accused of incestum , meaning unchastity , at any time and be sacrificed whether she 's innocent or guilty . licinia fully understands now why her predecessor was buried alive . ten years ago , the flame of vesta went out . the priestesses knew that they could n't keep it a secret . the future of rome depended upon it . they went to the chief priest and he opened an investigation to discover why the flame had failed . someone came forward and claimed that one of the vestals was no longer a virgin . that was the beginning of the end . the accused protested her innocence , but it was n't enough . she was tried and found guilty . that vestal 's death was meant to protect the city , but licinia weeps for what has been lost and for what she knows now . her own path was paved by the death of another , and her life could be taken just as easily for something as simple as a flame going out .
|
licinia fully understands now why her predecessor was buried alive . ten years ago , the flame of vesta went out . the priestesses knew that they could n't keep it a secret .
|
where is the temple of vesta located ?
|
you know , back in the '40s and '50s , the original standard television had a 4 to 3 width to height ratio . that shape was chosen to be a slight rectangle , but still mostly square , thus having the maximal screen area for the given dimensions . and that 's still the ratio on many tvs and computer monitors in today 's homes . the problem is , hardly anybody today treats video content in a 4 to 3 ratio . see , this whole problem started when people wanted to watch movies from the theater in the comfort of their own homes . movie screens are considerably larger than our home television . more important , the screen is completely different rectangle and ca n't mathematically fit on our tv screens without manipulation . a typical tv is one and a third times wider than it is tall some movie screens could be up to three times as wide as it is tall . so what 're we going to do to make it fit ? well , we have all kinds of options . well , we could squeeze and stretch and mangle everything onto the screen , to make it all fill up , and everyone would look ridiculously thin and compressed . the good news is the sound would be just fine , although i do n't think people would be too happy about that option , particularly the actors in the movie . we could just cut a chunk of the original movie like a cookie cutter and just see that frame of the movie . the problem with that would be people and objects would be speaking from off the screen , or , even worse , they might be cut in half . some movie editors use what 's called the `` pan and scan '' technique to allow the full height of the tv screen to be used , but pick and choose what section of the original movie should be shown on your screen thus eliminating the annoying cutting of people . imagine that job : staring at a 4 to 3 hole watching movies all day , deciding for everyone which piece of the screen is the most important part for people to see . now let 's do a little quick math . if we compare a major cinematic film produced on a 2.35 to 1 aspect frame with my standard 4 to 3 tv screen , we find out that only 55 % of the movie can actually fit on the screen at any one time . just over half ! you 've seen the disclaimer at the beginning of the movie on tv or dvd that says , `` this film has been modified from its original format to fit on your tv screen . '' well , what it should say is , `` we are only displaying 55 % of the movie of our choosing . '' now for all the full-screen tv lovers , this is your dilemma : do you want to see all the movie , or is 55 % good enough ? how about new tvs ? around the start of the century , some widescreen tvs emerged in a 16 to 9 , or 1.78 times wider than it is tall . well , this screen fits the movie a little better , but still only shows 75 % of the original movie at one time . suppose someone made a tv for your living room that was actually 2.35 to 1 to show those full movies ? well , the tv with the same height as the most current 50-inch tvs - that tv would be close to six feet long . and on top of that , you 'd only use the full screen when you watched movies . most of the other content would have to be stretched , or have empty space on the sides of the screen . of course , there is one more option . we can just shrink the movie screen proportionally , to fit the width of your home television . we can mathematically scale the original to fit exactly the width of the screen and this 'll preserve the entire movie screen , but show the infamous black bars along the top and bottom that so many television watchers abhor . of course , now you can argue that we 're only using 75 % of that screen . and that is where the real question is : do you want your full screen , or do you want to see the entire movie ? most likely , you just need a bigger tv .
|
well , this screen fits the movie a little better , but still only shows 75 % of the original movie at one time . suppose someone made a tv for your living room that was actually 2.35 to 1 to show those full movies ? well , the tv with the same height as the most current 50-inch tvs - that tv would be close to six feet long .
|
suppose someone made a tv for your living room that was actually 2.35:1 to show full movies , and the tv was the same height as the average 50 '' tv . how wide would the new tv have to be ?
|
in 1984 , an enterprising australian doctor named barry marshall decided to take a risk . too many of his patients were complaining of severe abdominal pain due to stomach ulcers , which are sores in the lining of the upper intestinal tract . at the time , few effective treatments for ulcers existed , and many sufferers required hospitalization or even surgery . desperate for answers , dr. marshall swallowed a cloudy broth of bacteria collected from the stomach of one of his patients . soon , dr. marshall was experiencing the same abdominal pain , bloating , and vomiting . ten days later , a camera called an endoscope peered inside his insides . marshall 's stomach was teeming with the same bacteria as his patient . he 'd also developed gastritis , or severe inflammation of the stomach , the hallmark precursor of ulcers . dr. marshall 's idea challenged a misconception that still persists to this day : that ulcers are caused by stress , food , or too much stomach acid . marshall thought the culprit was bacterial infections . initially , his idea was considered crazy by the brightest medical minds on the planet . but in 2005 , he and dr. robin warren received the ultimate validation when they were awarded the nobel prize for medicine . our stomachs are j-shaped organs with surprisingly intricate ecosystems awash in hormones and chemicals . the stomach is under constant attack by digestive enzymes , bile , proteins , microbes , and the stomach 's own acid . in response , it produces bicarbonate , mucus , and phospholipids called prostaglandins to maintain the integrity of its own lining . this delicate balance is constantly regulated and referred to as mucosal defense . since the mid-1800s , doctors thought stress alone caused most stomach ulcers . patients were given antidepressants or tranquilizers and told to visit health spas . this belief eventually shifted to the related notion of spicy foods and stress as culprits . yet no convincing study has ever demonstrated that emotional upset , psychological distress , or spicy food directly causes ulcer disease . by the mid-20th century , it was widely accepted that excess hydrochloric acid prompted the stomach to eat itself . fervent proponents of this idea were referred to as the acid mafia . the biggest hole in this theory was that antiacids only provide temporary relief . we now know that some rare ulcers are indeed caused by too much hydrochloric acid . but they make up less than 1 % of all cases . dr. marshall and dr. warren pinpointed a spiral-shaped bacteria called helicobacter pylori , or h. pylori , as the real offender . h. pylori is one of humanity 's oldest and most frequent companions , having joined us at least 50,000 years ago , and now found in 50 % of people . previously , we thought the stomach was sterile on account of it being such an acidic , hostile environment . yet h. pylori survives the acidic turmoil of the stomach with a variety of features that disrupt mucosal defense in its favor . for example , it produces an enzyme called urease that helps protect it from the surrounding gastric acid . h. pylori can make over 1,500 proteins , many of which are dedicated to maximizing its virulence . we still have unanswered questions , like why specific people develop ulcers at particular times . however , we do know individual genetics , other medical problems , use of certain medications , smoking , and the genetic diversity of helicobacter strains all play a role . in particular , certain pain medications used to reduce inflammation in joints have been discovered to work with h. pylori to create more severe stomach ulcers . dr. marshall ended up being fine after his famous , albeit dangerous , experiment . he ingested a course of antibiotics similar to the ones taken now for ulcers . to be treated by simple antibiotics is a modern triumph for a disease that previously needed surgery . marshall 's work also reminded us that scientific progress is not always smooth . but there 's value in trusting your proverbial , and sometimes literal , gut .
|
this delicate balance is constantly regulated and referred to as mucosal defense . since the mid-1800s , doctors thought stress alone caused most stomach ulcers . patients were given antidepressants or tranquilizers and told to visit health spas .
|
what are some of treatment strategies that were considered for stomach ulcers before antibiotics ?
|
translator : andrea mcdonough reviewer : bedirhan cinar in physics , the concepts of work and power help us understand and explain lots of things in our universe . let 's start with work . positive work is the energy we put into a system , and negative work is energy that is transferred out . think of positive work as money being added to your bank account , and negative work as money taken out . in the metric system , work and energy are measured in joules . as an example , let 's take a beautiful , old , mechanical grandfather clock . we transfer energy into the clock when we turn the crank to raise the heavy metal cylinders inside the clock . when we do this , we are doing positive work , adding energy to the clock , and that energy is stored as gravitational potential energy . we can calculate the amount of work done by multiplying the force we apply times the distance over which we apply the force . to raise the metal cylinders , we need to apply a force equal to their weight . that is , equal to the force of gravity pulling downward on the cylinders . these cylinders weight 300 newtons , which is pretty heavy , about as much as a small child , and if we lift them 1/2 meter , then we do 300 newtons times 1/2 meter or 150 joules of work . power is the rate at which energy is transferred . when we say rate , we mean the amount of energy transferred per unit of time . in the metric system , power is measured in joules per second , or watts . the term watt goes back to james watt , who came up with the concept of horsepower to measure the amount of power produced by a typical work horse . james watt was a producer of industrial steam engines , and he wanted his potential customers to be able to make comparisons between his steam engines and a familiar quanity , the power they could get from a working horse . it was such a useful idea that the metric system unit for power , the watt , is named after james watt . following in james watt 's footsteps , let 's compare the amount of power it takes to run this grandfather clock to the power we 'd need to run a bright , 100-watt light bulb . we can measure the power a person uses to wind the clock by dividing the amount of work they did by the time it took them to do it . if it takes 1 minute , or 60 seconds , to lift the weights , then they are doing 150 joules divided by 60 seconds , or 2.5 joules per second of work . they are adding energy to the clock in the rate of 2.5 watts . you would need about 40 times as much to run a bright , 100-watt light bulb . before we let the clock run , the energy is stored as gravitational potential energy of the cylinders . it 's like your bank account when you have just deposited money . but if we let the clock run , the cylinders slowly move downward . energy is leaving the clock . in fact , when the cylinders get to the bottom , all the energy that we put in will have left . so how much power does the clock use ? that is , how many joules of energy per second leave the clock if it takes 5 days for the cylinders to return to their original position ? we can figure this out because we already know how much work we did when we lifted the cylinders : 150 joules . but this time , it took 5 days rather than a minute . five days is 5 times 24 times 60 times 60 again or 432,000 seconds . so we divide the work done by the time and find the answer of about 0.00035 joules per second , or about 0.35 milliwatts . that 's a tiny amount of power . this clock uses so little power that you could run almost 300,000 clocks using the same power it takes to run one 100-watt light bulb . that 's right , you could run a clock in every house in a medium sized city with that much power . that 's a pretty amazing conclusion and it took knowledge of work and power to figure it out .
|
in the metric system , work and energy are measured in joules . as an example , let 's take a beautiful , old , mechanical grandfather clock . we transfer energy into the clock when we turn the crank to raise the heavy metal cylinders inside the clock .
|
when we turn the key on the back of an old grandfather clock , we are doing positive work . what 's another way to say this ?
|
here 's a conundrum : identical twins originate from the same dna , so how can they turn out so different even in traits that have a significant genetic component ? for instance , why might one twin get heart disease at 55 , while her sister runs marathons in perfect health ? nature versus nurture has a lot to do with it , but a deeper related answer can be found within something called epigenetics . that 's the study of how dna interacts with the multitude of smaller molecules found within cells , which can activate and deactivate genes . if you think of dna as a recipe book , those molecules are largely what determine what gets cooked when . they are n't making any conscious choices themselves , rather their presence and concentration within cells makes the difference . so how does that work ? genes in dna are expressed when they 're read and transcribed into rna , which is translated into proteins by structures called ribosomes . and proteins are much of what determines a cell 's characteristics and function . epigenetic changes can boost or interfere with the transcription of specific genes . the most common way interference happens is that dna , or the proteins it 's wrapped around , gets labeled with small chemical tags . the set of all of the chemical tags that are attached to the genome of a given cell is called the epigenome . some of these , like a methyl group , inhibit gene expression by derailing the cellular transcription machinery or causing the dna to coil more tightly , making it inaccessible . the gene is still there , but it 's silent . boosting transcription is essentially the opposite . some chemical tags will unwind the dna , making it easier to transcribe , which ramps up production of the associated protein . epigenetic changes can survive cell division , which means they could affect an organism for its entire life . sometimes that 's a good thing . epigenetic changes are part of normal development . the cells in an embryo start with one master genome . as the cells divide , some genes are activated and others inhibited . over time , through this epigenetic reprogramming , some cells develop into heart cells , and others into liver cells . each of the approximately 200 cell types in your body has essentially the same genome but its own distinct epigenome . the epigenome also mediates a lifelong dialogue between genes and the environment . the chemical tags that turn genes on and off can be influenced by factors including diet , chemical exposure , and medication . the resulting epigenetic changes can eventually lead to disease , if , for example , they turn off a gene that makes a tumor-suppressing protein . environmentally-induced epigenetic changes are part of the reason why genetically identical twins can grow up to have very different lives . as twins get older , their epigenomes diverge , affecting the way they age and their susceptibility to disease . even social experiences can cause epigenetic changes . in one famous experiment , when mother rats were n't attentive enough to their pups , genes in the babies that helped them manage stress were methylated and turned off . and it might not stop with that generation . most epigenetic marks are erased when egg and sperm cells are formed . but now researchers think that some of those imprints survive , passing those epigenetic traits on to the next generation . your mother 's or your father 's experiences as a child , or choices as adults , could actually shape your own epigenome . but even though epigenetic changes are sticky , they 're not necessarily permanent . a balanced lifestyle that includes a healthy diet , exercise , and avoiding exposure to contaminants may in the long run create a healthy epigenome . it 's an exciting time to be studying this . scientists are just beginning to understand how epigenetics could explain mechanisms of human development and aging , as well as the origins of cancer , heart disease , mental illness , addiction , and many other conditions . meanwhile , new genome editing techniques are making it much easier to identify which epigenetic changes really matter for health and disease . once we understand how our epigenome influences us , we might be able to influence it , too .
|
the set of all of the chemical tags that are attached to the genome of a given cell is called the epigenome . some of these , like a methyl group , inhibit gene expression by derailing the cellular transcription machinery or causing the dna to coil more tightly , making it inaccessible . the gene is still there , but it 's silent .
|
dna methylation is an epigenetic modification that is necessary for the proper functioning of cells . dna methylation is the attachment of methyl groups ( -ch3 ) to some cytosines in the genome . since methyl groups come in dietary items ( such as vitamins ) , what would happen if you often eat food poor in methyl groups ?
|
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 )
|
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 .
|
describe how judson brewer and his team used mindfulness training to try to get his patients to quit smoking .
|
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.