SCIENTIFIC AMERICAN JUNE 2015 PDF

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Risky Teen Behavior Is Driven by an Imbalance in Brain Development. By Jay N. Giedd. Inside NASA's New $Billion Deep-Space Rocket. Scientific American is the essential guide to the most awe-inspiring advances in science and technology, explaining how they change our. Mind. January · View Details · November Mind. November · View Details · September Mind. September · View Details · July .


Scientific American June 2015 Pdf

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There really is something to the idea of being hot-headed, he says. Brain temperature, which is affected by ambient temperature, does seem to be associated with aggressive mood states and aggressive behavior.

The bellicosity relates to a lack of oxygen in the regions of the brain that control our impulses, as the body directs more blood to the skins surface in an effort to cool off, Geher explains.

So you get more emotional reactions and less prefrontal, stepback, cognitive-processing kinds of actions. As for the protests, wars and revolutions supposedly fueled by sweat, the key factor may be survival, especially in drought-ridden areas.

When there are resource constraints when there is lack of food, when there is lack of access to Is it more stressful to be a boss or an underling? Top dogs may have the tougher job, but feeling in control can protect people from stress.

When youre in a society under stress and there is a danger of violence, peoples group identities become incredibly important, and violence begins to get organized around these group terms. We didnt expect for there to be nearly so many con vergent findings among so many different researchers, says economist Solomon Hsiang, now at U. Berkeley, who led the study. We were actually really stunned by the level of consistency in the findings that were out there and by the size of the effects we were observing.

The researchers used statistical modeling to show that aggression scales with a combination of temperature, place and time for example, if one U. The reasons behind the climate-violence link are com plex and not fully understood, although anyone who has lived through a heat wave can attest to one simple fact: When people are hot, it makes them cranky, says Brian Lickel, a social psychologist who is on the faculty of the Psychology of Peace and Violence program at the University of Massachusetts Amherst and who was not involved in the study.

It makes people more prone to anger, it makes people more frustrated, and it makes decision making more Too Hot to Be Angry? Multiple studies have proposed a link between hot weather and violent crime rates.

Yet debate rages over whether aggression wanes at very high temperatures. The resulting ani- for turning a handful of identical cells into all the specialized or. For starters. Pig eral different teams injected custom-designed mouse embryos heart valves are suitable substitutes for human tissue only after with rat stem cells and then allowed the resulting chimeras to de- they have been chemically treated to prevent this immune reac.

Relying on human origin. We still have much to learn about how taken from animals and human stem cells grown in cell cul- best to prepare human stem cells and animal embryos so that tures. This around the world. Gestation in pigs normally lasts about four months. We fertilize a pig egg with pig sperm.

Waiting lists could become a thing of the once identical cells soon start to move and behave differently as past as we develop a bountiful supply of replacement parts they divide. Each of these cells organs. The cells make and release special- to four weeks. We are nowhere near ready to take that final step of produc. Liver Gallbladder iPSCs begin to develop Dorsal into pancreas cells Ventral pancreatic pancreatic bud bud mice—except that they had the pancreas of a rat. A lot later the combined cell.

Within a few days several hundred cells have from farm animals for tens of thousands of suffering people formed a kind of ball within a ball. After completing several more intermediate exper. But even if we are unable to create fully formed two and then four seemingly identical cells. If success. Thanks to the complex interplay of genes and proteins.

Provided these experiments are successful—and this still incomplete understanding and a lot of trial and error. Then we transferred the chimeric embryos into ed by the precise location of different cells at various times with- surrogate sows. The raw materials we use include porcine eggs and sperm ing chimeric piglets. We also recognize how much this growth is guid- mature normally. Experimenting on human ent potential problems.

To date. Pigs also have Closer study of the human iPSCs created to date.

They are already so far along to becom- velop fully. If the added cells develop appropriately. Previous work has demonstrated. Using iPSCs would offer the added ad- concentrated our efforts on creating pig embryos. As the embryo grows. The fact that a single gene. By deleting the was transplanted in Because mice are too small to generate or. If we wait any longer.

Recent- gan unless we inject enough human stem cells that contain the ly researchers led by George Church of Harvard University have missing gene. Because normal human embryos require nine months to de. More recently. A few cells located in the middle layer. Because these iPSCs do not human cells to the somewhat longer pig timeline should require respond correctly. Other organs. Adapting tell them to grow into something else. My colleagues and I stopped the experimental em- means that emptying the niche for these organs will require de.

Hiromitsu Nakauchi. Biologists refer to this physiological state as be- sity of Tokyo. The result would ic of Barcelona. August September 3. There are additional concerns. Truly naive stem cells.

Scientific American Mind May June 2014

I believe the knowledge and techniques we dis- Moxie Foundation for supporting this early work when no one cover along the way will prove enormously valuable. The best way to prevent such a troubling outcome is to make our lab would not be able to accomplish such a task by our.

Together with embryologists. One of the thought our approach was even feasible. The tantly related species such as pigs. We have also begun tracing the way the hu. But we must pay special attention to three types— velop a little longer—until they are six weeks old. Imagine the ethical nightmare. But the preliminary re- best number of human iPSCs that need to be implanted for the sults I have described in this article make me cautiously opti- embryo to develop successfully and the time at which we need mistic that we may generate human organs from chimeric ani- to implant them.

I knew mal. Studies To date. At that point. We began injecting pig All bets are off. I vividly remember his advice: If we cannot figure out a bio. Scientists are people. And we can be overly ments have helped us to gain some basic knowledge about the optimistic about what our discoveries may imply—not just for development of chimeric embryos. We are starting to learn the our own fields but also for humankind. So far we have allowed the chimeric embryo to grow into a fetus. Although it is a long shot.

The guidelines that we and tell them when to stop growing—the better they may be able have worked out with regulatory authorities require us to sacri. We get excited about Overall.

November 5. We can forestall that problem by delet- mans and pigs are not as closely related. I am especially grateful to surmountable. Allowing these animals to then breed only way to determine whether human iPSCs can cross species could lead to the ethically disastrous case in which a fully human barriers and contribute to the formation of a human organ in a fetus the result of a humanized sperm from one pig fertilizing a pig is to role up your sleeves and do the experiment.

Yet even if we fail to create functional organs for the San Antonio Catholic University of Murcia in Spain and the transplantation. Wayt Gibbs Photographs by Chris Mueller. The shiny. Even if it succeeds. Warning lights start flashing.

For decades academic On the video feed overhead. Preliminary results have ic hurdles. The second discouraging example is ITER. The temperature inside that chamber will rise. There they collide and form a hot. In April. The warning lights switch off. The current energizes the ring magnets and nearly inexhaustible and have no carbon. Such fusion power plants would run on morning using power from the local grid. This reactor is an early prototype for a power plant balize its parts for a more advanced reactor—dubbed C-2W—to be completed in mid I click it.

The system stant. It will rely on giant superconducting magnets to control a team all the data it needed to move on. When you fire as many as pulled the plug on designing a prototype power plant. Two years ago Livermore Just another shot at fusion.

2016 Scientific American

They also would zap to come. One example is the million kilometers an hour. Clouds of hydrogen ions form at the opposing ends of the that have clarified some fusion science but are not on track to vacuum cylinder and are propelled toward the center at nearly a pump electricity into the grid by midcentury. Sitting in the control room W. A power plant room had dropped a wrench onto the concrete floor.

I see workers out on the floor of scientists have designed gargantuan machines intended to solve this nondescript warehouse near Irvine. The plants would charges up banks of beefy capacitors. ITER will make no electricity.

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All the new pioneers need to do is solve some of the hardest over loudspeakers. The backers are placing high-risk. That typically disruptive electric currents and magnetic fields. The tremes: Equally important. In this design. Frustrated senators voted 90—8 to cut off U. ITER aims for a low plasma density. Congress was.

Most of the newcomers are searching for sweeter spots that lie in the less explored middle ground. NIF and ITER are at opposite ends of a spectrum of plausible designs that spans a huge range of plasma densities and energy- confinement times a measure of how long heat stays inside the plasma.

Forewarned by the glacial progress of the giants. Tri Alpha claims to have raised hundreds of millions of greater than about seconds per cubic centimeter. That pleases their investors. Fission reactors. A big opportunity. But after a subsequent though guarded vote of confidence by the U. A get the candle lit. Another fast-moving group is ITER. Two atomic nuclei.

Department of Energy. As of May. As a rule of thumb. To deliver. Any show-stopping flaws in these schemes most likely will plenty of space to have a bad surprise—or a good one. Full operation will not come until at the earliest. In a power reactor. But the tests plasma. The fusion converts the missing mass into energy.

Just three scale reactor that powers itself as well as the grid. The blobs remained stable and hot for five milliseconds. The designs shown here are for commercial-style reactors. Neutral beam injector 8 total Beams run along tube.

Laberge describes the stability problem. They have essentially solved tall. With each beat.

The entire neutral atoms into the edges of the tube process would repeat once every second. The liquid chamber degrees Celsius for fusion reactions to metal captures the neutrons and heat take off. A brief. Eight injectors shoot beams of released by the fusion. If all goes well. But the Sandia system is. The team is trying to improve the sides. The machine imposes a covers the open end of the fuel target may be scattering the separate magnetic field to keep the resulting plasma from light.

Laberge argues. It has in experiments thus far. The thin window that ionizes the fuel as it starts to implode. Sandia researchers calculate that it might be.

That is more than 20 times for late Daniel Sinars. But if But competition could change that sentiment. Half a continent away in New Mexico.

According to Slutz. Is that enough to achieve General Fusion must struggle with unproved physics. A brief trillion-watt laser blast nearly as much as their models predict. For a squirting out the ends of the cylinder. But a laser may simply be the wrong tool for the job.

It is an elegant solution on a whiteboard, but no one has ever built such a system. And Laberge worries that as shock waves from the pistons pass through the lead-lithium mixture, some of the metal could spray into the plasma, squelching the fusion.

The start-ups Currently that race in the U. Federal money for alternative paths to fusion has been face numerous practical challenges. Scientists Maybe, maybe not. Tri Alpha is pursuing proton-boron fusion precisely to avoid Is it worth taking a few more shots? Plasma Physics: The Fusion Upstarts. But that technology does not yet exist. We once believed that the continents were fixed on the surface of Earth; now we know they move. We thought margarine was healthier than butter and that hormone-replacement therapy was the right treatment for vast numbers of postmenopausal women; now we know better.

But while scientists do not know everything, there is plenty they. And especially during this political season, it is dispiriting to see how many people—including political candidates—bizarrely reject some of the most basic, evidence-based truths that underlie modern science.

Psychological research has shown that being confronted with that mounting evidence can actually harden the positions of the truth deniers, so we do not pretend that the essays that follow will fix the problem. Nevertheless, we feel it is our duty to point out that some things actually are true, even in the constantly growing and evolving world of science. Because of a convergence of evidence from many lines of inquiry.

Darwin came to this conclusion: Not only are the dates consistent. It is not as if one scientist finds that a fossil hominin is 1. If new species are created naturally—not supernatu- rally—what place. No wonder that more than a cen- tury and a half later people of some religious faiths still find the theo- But in those intervening years scientists ry so terribly threatening. Nobody knows where this have never been shown to be dangerous. For example: The ages are given in estimates.

And of course. Dobzhansky famously noted. The consistency of dating techniques also gives us confidence that the theory is true. Explanation for vinced quite contrary to opinion I started with that species are not it is like confessing a mur- the Diversity der immutable. Trilobites and mammals are separated by many millions of years. A product called Oscillococcinum is sold based on the unscientific thinking of a single mis. They consult two books. That means Muscovy duck the heart and liver.

The el Hahnemann. What are you afraid of? You do have to replace fluids lost to urine and perspira no access to healthy food or a balanced diet. If any of that makes sense to you. It is active ingredient. They ask way to explain homeopathic theory is with this example: If coffee a laundry list of irrelevant questions What color are your eyes? What keeps you awake. Any chemis- and Its Kindred Delusions. It is inconsistent with our basic knowledge of physics.

All that remains is the quack. We have learned plenty since then. The cabal would also have to fake all the data from past climates that tells us there is no magic mechanism clouds or otherwise that will save us from the well-established warming effects of carbon dioxide acting in concert with water vapor.

Our understanding of the connection between greenhouse gases and global warming rests on the same principles that underlie heat-seeking missiles. Some of my favorites: Berlin wall. Likewise the carbon isotope and car- bon budget data that prove that the carbon dioxide accumulating in the atmosphere really does come from deforestation and burning fossil fuels. If it is a conspiracy. Global warming is a problem. Homeopathy was bunk in Earth is not flat. It would have to fake the observed conjunction of strato- 0 spheric cooling with tropospheric warming.

Irish-born physicist John Tyndall have used homeopathy instead of effective drugs. Science rewards those who overturn previous dogma think quantum theory versus classical mechanics. People have died. I wish they radiation emitted back into space. As Edzard Ernst. It adds up to an awful lot of stuff to fake and makes faking the moon landing look like a piece of cake.

It would take quite a conspiracy to fake all that. Energy is conserved. And so on and so forth. People temporary Gustav Kirchhoff.

You know it. By now There were many later developments in the 20th century. The Conspiracy Theories ed that it works no better than placebos. Austrian Ludwig Boltzmann in the mids and his German con- strates the inability of the general public to think critically. At the time. As a consequence. Animal tests But despite a handful of suspicious-looking studies. If the disorder is genetic. For the most part. Frederick Banting and Charles Best discovered insulin. It is nice to be able to point a finger at an evil force causing autism.

Another possibility is that the notion that vaccines cause autism is comforting—certainly far more comforting than studies that have shown a genetic basis.

Until a clear cause and cure for autism emerge. The most encouraging aspect of the vaccine-autism controversy has been the emergence of academics. If autism is caused by events occurring out- side the womb. Criminal activity does not increase during the full moon.

There are several plausible rea- sons why they feel this way. Conspiracy theorists argue that the only reason studies have shown that vaccines do not cause autism is that a vast international con- spiracy is hiding the truth. Although only a small group of parents hold this belief. And everyone loves a bogeyman. Since then.

That should tell you something: Assuming an aliens- without-borders effort. Even aside from the formi- dable technical challenges of interstellar travel.

Magazine Scientific American November 2016

If aliens have been here weekly radio program. Aurum Press. Seth Mnookin. The Panic Virus: If despite nonprofit organization the lack of good evidence. I think the United Nations would notice. Most of these can be explained as aircraft.

Unless the extraterrestrials come from a very close star system. Unless extraterrestrials prefer Americans and exceptionalism aside.

There remains no scientifically validated evidence that extraterrestrials have been here. The He also co-hosts a Roswell incident was nearly 70 years ago. Many people believe the latter.

The History of a Modern Myth. Global Weirdness. The majority of the evidence is composed of sightings—eyewitness accounts. They say Evidence of Alien that the government knows the aliens are here Visitations Exists but keeps the evidence under wraps at Area 51 or some other top-secret venue. Viking Adult. Why are they here now? Big Picture Science. The pyramids. Climate Central. The killer whale findings raise ques- emergence of new species.

Whatever the motivation behind it. His research focuses on the mechanisms that create. If so. The sun has burned off most of the morning mist. Exactly why the creatures engage in this scraping behavior. Despite their name. Plumper and Kaikash gently scrape their bodies against the small.

British Columbia. Observations made since the s have diversification: These cultural and physical differences. J ust offshore from the pebble beaches of Bere Point on Malcolm Island. I watch from the boat as three killer whale brothers named Cracroft. That is.

University of London. Physical traits. In the favored scenario. Soon they will leave to hunt for salmon or look for mates. It is part of the distinctive cultural fabric of the northern resident killer whales. The brothers have already spent the better part of an hour here absorbed in this activity.

The northern resident killer whales are not the only ones Intriguingly. Mounting evidence indicates that cul. Documented examples specialize in hunting Antarctic minke whales. For the facial features and fingerprints to identify individual humans. Were the populations already living in the same whales live side by side without fraternizing. One type. There research begun in the early s inconclusive for many Northern Hemisphere killer whales.

Bigg and his colleagues. Biologists can use those traits to sity in England and his collaborators hint that these ecotypes identify individual killer whales. Burdin of the Russian Academy found only in isolated springs in California and Nevada shows of Sciences. For its part humans. Current evidence is mostly the Northeast Pacific.

Andrew sary for speciation to occur. Yet scientists have now shown that in various marine the killer whales. Resident ent environmental conditions.

If this separation persists long enough. Deecke of the University of Cumbria in England. Ford and graphical barrier of some kind—perhaps a mountain range. In the parlance of The Southern Hemisphere hosts geographically overlapping biologists. B Type 1 Preferred prey: They also differ in their physical features. These separate groups.

Their cultural traditions probably differ depending on their preferred prey. The whales choose mates that share their customs rather than foreigners from other eco- types.

Yet studies show that in var- ious regions distinct forms. Culture appears to keep the ecotypes apart. Whether the northern Pacific halibut ecotypes began to diverge while living and sleeper sharks in the same region or whether they started to differentiate at a time D Transient earlier in the evolutionary history Preferred prey: E Type 2 Preferred prey: Patagonian toothfish J Type C Preferred prey: Antarctic toothfish November For example.

Scientists have observed this behavior in two groups records maintained and occasionally published by SeaWorld. In May of this year. A pod of the killer whales will herd a Because these and other behaviors are found only in certain school of herring into a tight ball close to the water surface. But the most dramatic specializations have dubbed carousel feeding—to hunt the herring that form the occurred in cultural behaviors related to food acquisition.

But the ice-pack whales are diversifying by exploiting different food sources and killer whales have learned to create waves that wash the seals evolving various traits that presumably help them get those over the ice float and into the water. Some of these distinguishing features are physical. Rather mounting evidence suggests that submerged until they are just meters away from their quarry. What is keeping them separate now? Breeding the beach.

In Antarctica. G-clan and R-clan for the tions that live side by side. Do other is.At first. It is as if entanglement can be viewed as a thread con- tum state of the second.

Abbate well we do. Libeskind and R. It is active ingredient. Yet natural selection promotes it be more persuasive if we were to talk about qualia as art rath- only variants that contribute to biological survival.

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From the outside the wormhole looks like a pair of black ticles have been prepared. If sensations are art, the artist behind them is actually not extensive psychological and evolutionary arguments for the individual brain as such. In an election year.

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Browse my other posts. I have always been a very creative person and find it relaxing to indulge in bandy. I do relish studying docunments yearningly.
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