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germanium is the first element in the periodic table , beginning at hydrogen , that ’ s named after a country : it is named after germany . there are other elements named after france and poland and america but we will come to those later . one of the things about germanium and what really makes it important in the per... | if you look at it in visible light it looks like a metal . germanium na , na , n-na na . i have used germanium mirrors in some of my experiments . the lasers that i used when i was younger had a germanium mirror that let the light out at the front of it and germanium is used quite widely in electronics . this is quite ... | germanium is in the same group as carbon and silicon , but while both carbon and silicon have the stable oxidation state of +4 , what about germanium ? why is this the case ?
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at pixar , we 're all about telling stories , but one story that has n't been told very much is the huge degree to which math is used in the production of our films . the math that you 're learning in middle school and high school is used all the time at pixar . so , let 's start with a very simple example . anybody re... | it 's dory . okay , that was easy . here 's a little harder one .
| design a character that would be really easy to describe mathematically . what makes the design easy ?
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is it a flying comma , or a quotation mark chopped in half ? either way , you may already be well-versed in how to use the apostrophe , but here 's a quick refresher on its usage . the apostrophe can be used in three ways : to mark possession , to mark contraction , to mark the plural of single letters . most of the ti... | certain pronouns already have possession built in and do n't need an apostrophe . remembering that will help you avoid one of the trickiest snags in english grammar : its vs. it 's . `` it 's '' only take an apostrophe when it 's a contraction for `` it is '' or `` it has . ''
| as the english language evolves , so do english grammar `` rules '' and `` style '' choices . why ?
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the biggest kidney stone on record weighed more than a kilogram and was 17 centimeters in diameter . the patient did n't actually swallow a stone the size of a coconut . kidney stones form inside the body , but unfortunately , they 're extremely painful to get out . a kidney stone is a hard mass of crystals that can fo... | stones can also be surgically removed through an incision in the patient 's back or groin . what about just avoiding kidney stones in the first place ? for people prone to them , their doctor may recommend drinking plenty of water , which dilutes the calcium oxalate and other compounds that eventually build up into pai... | what is happening to the incidence of kidney stones in the human population ?
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despite advances in medicine , cancer remains one of the most frightening diagnoses patients can receive . what makes it so difficult to cure is that it 's not one illness , but a family of over 100 diseases occurring in different types of cells . and one type of cancer has the unfortunate distinction of afflicting chi... | to restore the normal function of the blood , leukemic cells have to be eliminated . but because leukemias are not solid tumors , they ca n't be removed surgically . instead , the cells are killed inside the body using various treatments that include chemotherapy , a combination of drugs that destroys quickly multiplyi... | doctors ca n't use surgery to remove leukemia because :
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brady haran : hey there , everyone . today 's video is about richard feynman -- a lot of people 's favorite scientist -- and safe breaking . but i just wanted to point out at the start that most safes , or secure filing cabinets , actually have one dial . and if you 've got a three number combination , for example , yo... | i do n't want to get all the safe enthusiasts out there too fired up and angry in the comments section . but for now , here 's professor bowley with his pretend safe and the story of richard feynman and his world war ii safe cracking . professor roger bowley : i 'm talking about feynman and how he managed to crack safe... | why did richard feynman start cracking safes ?
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right now , you 're probably sitting down to watch this video and staying seated for a few minutes to view it is probably okay . but the longer you stay put , the more agitated your body becomes . it sits there counting down the moments until you stand up again and take it for a walk . that may sound ridiculous . our b... | it sits there counting down the moments until you stand up again and take it for a walk . that may sound ridiculous . our bodies love to sit , right ?
| sitting may help your brain function better .
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you 've probably heard of the human genome , the huge collection of genes inside each and every one of your cells . you probably also know that we 've sequenced the human genome , but what does that actually mean ? how do you sequence someone 's genome ? let 's back up a bit . what is a genome ? well , a genome is all ... | you probably also know that we 've sequenced the human genome , but what does that actually mean ? how do you sequence someone 's genome ? let 's back up a bit .
| if there are 3 billion letters in the reference genome , how much did it cost per letter to sequence the first human genome ?
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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 , t... | 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 iss... | what is the second most common burial method ?
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the secrets of the x chromosome . these women are identical twins . they have the same nose , the same hair color , the same eye color . but this one is color blind for green light , and this one is n't . how is that possible ? the answer lies in their genes . for humans , the genetic information that determines our ph... | now we can explain our color blind twin . both sisters inherited one mutant copy of the green receptor gene and one normally functioning copy . the embryo split into twins before x inactivation , so each twin ended up with a different inactivation pattern .
| what is one cause of colorblindness ?
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testing , testing , one , two , three . when your band is trying to perform , feedback is an annoying obstacle , but in the grand orchestra of nature , feedback is not only beneficial , it 's what makes everything work . what exactly is feedback ? the key element , whether in sound , the environment or social science ,... | a food web containing twenty populations can generate thousands of loops of up to twenty links in length . but instead of forming a disordered cacophany , feedback loops in ecological systems play together , creating regular patterns just like multiple instruments , coming together to create a complex but harmonious pi... | how do all the feedbacks together in an ecosystem create harmony ? one important mechanism is :
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imagine if half the people in your neighborhood , your city , or even your whole country were wiped out . it might sound like something out of an apocalyptic horror film , but it actually happened in the 14th century during a disease outbreak known as the black death . spreading from china through asia , the middle eas... | as a result , most europeans in the early 14th century experienced a steady decline in living standards , marked by famine , poverty and poor health , leaving them vulnerable to infection . and indeed , the skeletal remains of black death victims found in london show telltale signs of malnutrition and prior illness . t... | what proportion of the affected population was killed by the black death ?
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with social media sites being used by ⅓ of the entire world , they ’ ve clearly had an major influence on society . but what about our bodies ? here are 5 crazy ways that social media and the internet are affecting your brain right now ! can ’ t log off ? surprisingly , 5-10 % of internet users are actually unable to c... | or wait ... did it even buzz ? phantom vibration syndrome is a relatively new psychological phenomenon where you think you felt your phone go off , but it didn ’ t . in one study , 89 % of test subjects said they experienced this at least once every two weeks .
| in your own words , explain phantom vibration syndrome . have you ever experienced it ?
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if i say , `` venice , '' do you imagine yourself gliding down the grand canal , serenaded by a gondolier ? there 's no doubt that the gondola is a symbol of venice , italy , but how did this curious banana-shaped black boat get its distinctive look ? the origins of the venetian gondola are lost to history , but by the... | specialized artisans supplied their gondola-making colleagues with elaborate covered passenger compartments , upholstery and ornaments of steel and brass . oar makers became integral partners to the gondola makers . the venetian oarlock , or fórcola , began as a simple wooden fork , but evolved into a high-precision to... | why do you think that gondoliers and gondola makers appear less frequently in historical documents than , let ’ s say , politicians or bankers ?
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translator : andrea mcdonough reviewer : bedirhan cinar you might have heard that we 're running out of fresh water . this might sound strange to you because , if you live in a place where water flows freely from the tap or shower at any time , it sure does n't seem like a big deal . it 's just there , right ? wrong ! ... | agricultural and industrial patterns of water use need serious attention . how do our societies value water ? distribute it ?
| in your own words , explain how our societies value water .
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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 , th... | 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 .
| in a chemical reaction , atoms do which of the following ?
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you might remember a pair of ted-ed lessons written and performed by two educators , brad voytek and tim verstynen . these two scientists used a drooling , hag-faced , animated zombie as a mechanism to model the symptoms and medical diagnosis process for various neurological conditions . for example , they spent time d... | you might remember a pair of ted-ed lessons written and performed by two educators , brad voytek and tim verstynen . these two scientists used a drooling , hag-faced , animated zombie as a mechanism to model the symptoms and medical diagnosis process for various neurological conditions . for example , they spent time d... | the two educators used a drooling , hag-faced , animated zombie as a mechanism to model the symptoms and medical diagnosis process for various neurological conditions .
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testing , testing , one , two , three . when your band is trying to perform , feedback is an annoying obstacle , but in the grand orchestra of nature , feedback is not only beneficial , it 's what makes everything work . what exactly is feedback ? the key element , whether in sound , the environment or social science ,... | when your band is trying to perform , feedback is an annoying obstacle , but in the grand orchestra of nature , feedback is not only beneficial , it 's what makes everything work . what exactly is feedback ? the key element , whether in sound , the environment or social science , is a phenomenon called mutual causal in... | describe three examples of positive feedback and three of negative feedback , in other systems that have many interacting parts – such as economic , social , political systems .
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when you hear the word art , what comes to mind ? a painting , like the mona lisa , or a famous sculpture or a building ? what about a vase or a quilt or a violin ? are those things art , too , or are they craft ? and what 's the difference anyway ? it turns out that the answer is not so simple . a spoon or a saddle ma... | in fact , some works that might be considered craft , a peruvian rug , a ming dynasty vase , a totem pole , are considered the cultures ' preeminent visual forms . when art historians of the 19th century saw that the art of some non-western cultures did not change for thousands of years , they classified the works as p... | what are some of the ways in which renaissance culture changed people ’ s views of the role of art—and artists—in western society ?
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if i were to distill the 20 years of elephant research that i 've done into one sentence , what would it be ? what could i tell you ? i would say that elephants are just like us ! and what do i mean by that ? it takes a lot of patience to be out there in the field and trying to figure out patterns of these very slow an... | well , in fact , their families are very similar to ours . and family is extremely important to elephants . they grow up in very tight-knit families and they have extended families .
| when an extended family group of elephants meets up at a waterhole when they haven ’ t seen each other in a while ________ .
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this is a tomato plant , and this is an aphid slowly killing the tomato plant by sucking the juice out of its leaves . the tomato is putting up a fight using both physical and chemical defenses to repel the attacking insects . but that 's not all . the tomato is also releasing compounds that signal nearby tomato plants... | they can cause tiny wounds in the inside of animals ' mouths , which create entry points for toxins . the mimosa plant has a strategy designed to prevent herbivores from taking a bite at all . specialized mechanoreceptor cells detect touch and shoot an electrical signal through the leaflet to its base causing cells the... | one of the defense strategies that mimosa plants use against herbivores is :
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anyone who has played a claw machine can relate to the experience of having the claw perfectly positioned only to see it weakly graze the prize before pulling back up . `` no man ! '' it may seem like the machine is n't even trying . and well ... `` it is not your imagination , those claw machines are rigged ! '' there... | and that just ruins everything . so , most of the time claw machines are more like slot machines , than like skeeball or wack-a-mole . `` who 's in charge here ! ''
| the first claw machines were explicitly marketed as highly profitable for owners . when were they invented and why were they so popular at the time ?
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good morning , john ! today is the day after thanksgiving here in america . traditionally , the day when we buy all the things ! actually , more traditionally at my house , it 's the day when we do n't leave the house ; because black friday.. terrifies me . for people who are n't american , the very ominous-sounding bl... | despite the fact that it has kind of this ominous-sounding name , it has been billed as the biggest and most important and best holiday shopping day of the year ; which is actually not true . we are.. a nation of procrastinators ; and thus , the biggest shopping day of the year is christmas eve . it seems a little bit ... | what is the biggest shopping day of the year in the united states ?
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if you ever find yourself gazing at falling snow , why not catch a few snowflakes on your glove and examine their shapes ? you might notice that they look symmetrical , and if you look closely , you 'll see they have six sides . you could say a snowflake is simply frozen water , but compare one with an ice cube from th... | completely dry snow is very difficult to ski on because there 's too much friction between the jagged snowflakes and the ski surface . so what 's happening is that as skis move , they rub the surface of the snow and warm it up , creating a thin layer of water , which helps them slide along . so technically , it 's not ... | why can a skier slide over snow ?
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in 1985 , three researchers on a dolphin-studying expedition got a little bored . to lighten things up , one pretended to be poseidon by placing a seaweed garland on his head and then throwing it into the ocean . moments later , a dolphin surfaced with the seaweed crowning her head . sure , this could have been a coinc... | this sort of cultural transmission even extends to tool use . one group of bottlenose dolphins off the australian coast nicknamed the dolphin sponge club , has learned how to cover their rostrums with sponges when rooting in sharp corals , passing the knowledge from mother to daughter . dolphins have even demonstrated ... | the dolphin sponge club :
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in 1996 , 56 volunteers took part in a study to test a new painkiller called trivaricaine . on each subject , one index finger was covered in the new painkiller while the other remained untouched . then , both were squeezed in painful clamps . the subjects reported that the treated finger hurt less than the untreated o... | in these cases , placebos are often used as a control to fine-tune the trial so that the effects of the new versus the old or alternative drug can be precisely compared . but of course , we know the placebos exert their own influence , too . thanks to the placebo effect , patients have experienced relief from a range o... | list some of the benefits that patients have been known to experience while under the influence of placebos .
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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... | 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 .
| a large protein consisting of 94 atoms has ____ vibrational ‘ degrees of freedom . ’
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some people ca n't see the forest for the trees , but before stephen sillett , no one could see or even imagine the forest in the trees . stephen was an explorer of new worlds from the start . he spent his boyhood in harrisburg , pennsylvania reading tolkien and playing dungeons and dragons with his brother scott . but... | he noticed that the higher he went , the thicker the branches were , not the case with most trees . he found moist mats of soil many inches thick , made from fallen needles , bark , other plant debris and dust from the sky piled on the tops of the large branches . he even found reiterations : new redwood tree trunks gr... | soil mats form on the large branches over long periods of time . explain the importance of these soil mats in the redwood canopy ecosystem .
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how many times can you fold a piece of paper ? assume that one had a piece of paper that was very fine , like the kind they typically use to print the bible . in reality , it seems like a piece of silk . to qualify these ideas , let 's say you have a paper that 's one-thousandth of a centimeter in thickness . that is 1... | how many times can you fold a piece of paper ? assume that one had a piece of paper that was very fine , like the kind they typically use to print the bible .
| if we fold the paper ten times , how thick would it be ?
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mastering any physical skill , be it performing a pirouette , playing an instrument , or throwing a baseball , takes practice . practice is the repetition of an action with the goal of improvement , and it helps us perform with more ease , speed , and confidence . so what does practice do in our brains to make us bette... | mastering any physical skill , be it performing a pirouette , playing an instrument , or throwing a baseball , takes practice . practice is the repetition of an action with the goal of improvement , and it helps us perform with more ease , speed , and confidence .
| how is slow practice beneficial in the development of complex , coordinated skills in dance , sports , the martial arts , and playing a musical instrument ?
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some superheros can move faster than the wind . the men in apollo 10 reached a record-breaking speed of around 25,000 miles per hour when the shuttle re-entered the earth 's atmosphere in 1969 . would n't we save a lot of time to be able to move that fast ? but what 's the catch ? air is not empty . elements like oxyge... | that sounds very romantic , but , in reality , that girl will probably suffer more damage from the hero than the bullet if he moved her at super speed . newton 's first law of motion deals with inertia , which is the resistance to a change in its state of motion . so , an object will continue moving or staying at the s... | newton ’ s first law of motion deals with inertia , which is
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so i 'm here today to encourage you to think about new york city , and not just as one of humanity 's greatest achievements , but as home to native wildlife that are subject to a grand evolutionary experiment . so take this forested hillside in northern manhattan , for example . this is one of the last areas left in th... | this guy , we catch in almost every forested area in new york city . this is the white-footed mouse -- not the mouse you find running around your apartment . this is a native species , been here long before humans .
| munshi-south and his colleagues are analyzing dna from the white-footed mouse in order to
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translator : andrea mcdonough reviewer : jessica ruby how big was that fish you caught ? this big ? this big ? this big ? without photographic evidence , there 's nothing that proves you caught a whopper , and that 's been true since the dawn of fishing . in fact , hundreds of years ago , long before photography could ... | in fact , hundreds of years ago , long before photography could capture the moment , japanese fishermen invented their own way to record trophy catches . they called it gyotaku . gyotaku is the ancient art of printing fish that originated in japan as a way to record trophy catches prior to the modern day camera .
| what was the original purpose for gyotaku ?
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translator : andrea mcdonough reviewer : bedirhan cinar being human , we each view ourselves as a unique and independent individual , but we 're never alone ! millions of microscopic beings inhabit our bodies , and no two bodies are the same . each is a different habitat for microbial communities : from the arid desert... | every person has a unique and diverse community of gut microbes that can process food in different ways . one person 's gut microbes may be capable of releasing only a fraction of the calories that another person 's gut microbes can extract . so , what determines the membership of our gut microbial community ?
| one person 's gut microbes may be capable of releasing only a fraction of the calories that another person 's gut microbes can extract .
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4,000 years ago , the ancient sumerians made a surprising discovery . if they scraped the bark off a particular kind of tree and ate it , their pain disappeared . little did they know that why they 'd found was destined to influence the future course of medicine . what the sumerians had discovered was a precursor to th... | in fact , the 1982 nobel prize winners also demonstrated that aspirin slows production of thromboxanes , chemicals that cause clumping of platelets , which in turn form blood clots . a landmark clinical trial showed that aspirin reduced heart attack risk by 44 % in participants who took the drug . today , we prescribe ... | aspirin is one of the various strategies used to prevent heart attacks . what are some of the other approaches people could take to reduce their risk ?
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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 sufferer... | 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 peo... | which of the following factors most influences when helicobacter pylori prompts the development of ulcers ?
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in 1978 , louise brown became the world 's first baby to be born by in vitro fertilization , or ivf . her birth revolutionized the field of reproductive medicine . given that approximately one in eight heterosexual couples has difficulty conceiving , and that homosexual couples and single parents often need clinical he... | in 1978 , louise brown became the world 's first baby to be born by in vitro fertilization , or ivf . her birth revolutionized the field of reproductive medicine .
| although many patients want twins , a common phenomenon with in vitro fertilization , why has there been a push to try to reduce the number of twins born from ivf ?
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figs are one of my favorite foods . they 're sweet and floral , and there 's something about the texture that i find so delightful—the outside is soft , but the seeds in the middle give you this totally satisfying crunch . but it turns out that many species of figs contain the bodies of dead wasps . i 'm anna and this ... | but if the flowers are trapped inside the fig how do they get pollinated ? well , that 's where fig wasps come in . in most species , pregnant female fig wasps carrying pollen are attracted to young figs . they enter through a tiny opening at the fig ’ s bottom that ’ s highly selective—it usually only lets in the exac... | before the newly-hatched female fig wasps leave the fig , they pick up some pollen , then bore their way out through tiny holes . so when they enter a new fig what two tasks are they accomplishing ?
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translator : andrea mcdonough reviewer : bedirhan cinar this is zeno of elea , an ancient greek philosopher famous for inventing a number of paradoxes , arguments that seem logical , but whose conclusion is absurd or contradictory . for more than 2,000 years , zeno 's mind-bending riddles have inspired mathematicians a... | now you can see why we choose this particular way of cutting up the square . we 've obtained the same infinite series as we had for the time of zeno 's journey . as we construct more and more blue pieces , to use the math jargon , as we take the limit as n tends to infinity , the entire square becomes covered with blue... | an infinite series :
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meet our chemist , harriet . she has a chemical reaction that needs to occur more quickly . a chemist has some processes at her disposal that can help her speed up her reaction , and she knows of five ways . and to remember them , she thinks back to her days as a high school student , and the day she got a date for the... | in order to facilitate this improved dance-date-getting process , i propose five changes to all schools that parallel harriet 's five ways to increase chemical reaction rates . first , i propose that we shrink the size of the hallways . this will make it more difficult to safely navigate the hallways and will cause mor... | in this analogy , shrinking the hallways is analogous to :
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there are many stories that can be told about world war ii , from the tragic to the inspring . but perhaps one of the most heartrending experiences was that of the akune family , divided by the war against each other and against their own identities . ichiro akune and his wife yukiye immigrated to america from japan in... | the brothers not only had very limited contact with their family in japan , but found themselves confined to a camp in a remote part of colorado . but their story took another twist when recruiters from the us army 's military intelligence service arrived at the camp looking for japanese-speaking volunteers . despite t... | what was the primary reason harry and ken akune joined the u.s. army 's military intelligence service ?
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