[28/08T][lghscu][T备考部分记录]

SallyberryUID: 2532935

嘿嘿。你的贴子还火嘛~~           LIZY

lghscuUID: 2552043

http://www.scientificamerican.com/article.cfm?id=guaranteed-global-warming-with-existing-fossil-fuel-infrastructure

September 9, 2010 | 5 comments
How Much Global Warming Is Guaranteed Even If We Stopped Building Coal-Fired Power Plants Today?
All the world's power plants, vehicles and factories that presently exist may not emit enough carbon dioxide to cause catastrophic climate change
By David Biello  


Humanity has yet(: up to now : so far <hasn't done much yet> ― often used to imply the negative of a following infinitive <have yet to win a game>) to reach the point of no return when it comes to catastrophic climate change, according to new calculations. If we content ourselves with the existing fossil-fuel infrastructure we can hold greenhouse gas concentrations below 450 parts per million in the atmosphere and limit warming to below 2 degrees Celsius above preindustrial levels—both common benchmarks for international efforts to avoid the worst impacts of ongoing climate change—according to a new analysis in the September 10 issue of Science. The bad news is we are adding more fossil-fuel infrastructure—oil-burning cars, coal-fired power plants, industrial factories consuming natural gas—every day.

A team of scientists analyzed the existing fossil-fuel infrastructure to determine how much greenhouse gas emissions we have committed to if all of that kit(: a group of persons or things ― usually used in the phrase the whole kit and caboodle) is utilized for its entire expected lifetime. The answer: an average of 496 billion metric tons more of carbon dioxide added to the atmosphere between now and 2060 in "committed emissions".

That assumes life spans of roughly 40 years for a coal-fired power plant and 17 years for a typical car—potentially major under- and overestimates, respectively, given that some coal-fired power plants still in use in the U.S. first fired up in the 1950s. Plugging that roughly 500 gigatonne number into a computer-generated climate model predicted CO2 levels would then peak at less than 430 ppm with an attendant warming of 1.3 degrees C above preindustrial average temperature. That's just 50 ppm(parts per million) higher than present levels and 150 ppm higher than preindustrial atmospheric concentrations.

Still, we are rapidly approaching a point of no return, cautions climate modeler Ken Caldeira of the Carnegie Institution for Science's Department of Global Ecology at Stanford University, who participated in the study. "There is little doubt that more CO2-emitting devices will be built," the researchers wrote. After all, the study does not take into account all the enabling infrastructure—such as highways, gas stations and refineries—that contribute inertia that holds back significant changes to lower-emitting alternatives, such as electric cars.

And since 2000 the world has added 416 gigawatts of coal-fired power plants, 449 gigawatts ofnatural gas–fired power plants and even 47.5 gigawatts of oil-fired power plants, according to the study's figures. China alone is already responsible for more than a third of the global "committed emissions," including adding 2,000 cars a week to the streets of Beijing as well as 322 gigawatts of coal-fired power plants built since 2000.

The U.S.—the world's largest emitter of greenhouse gases per person, among major countries—has continued a transition to less CO2-intensive energy use that started in the early 20th century. Natural gas—which emits 40 percent less CO2 than coal when burned—now dominates new power plants (nearly 188 gigawatts added since 2000) along with wind (roughly 28 gigawatts added), a trend broadly similar to other developed nations such as Japan or Germany.

But the U.S. still generates half of its electricity via coal burning—and what replaces those power plants over the next several decades will play a huge role in determining the ultimate degree of global climate change. Coal-burning poses other threats as well, including the toxic coal ash that can spill from the impoundments where it is kept; other polluting emissions that cause acid rain and smog; and the soot that causes an estimated 13,200 extra deaths and nearly 218,000 asthma attacks per year, according to a report from the Clean Air Task Force, an environmental group. "Unfortunately, persistently elevated levels of fine particle pollution are common across wide swaths of the country," reveals the 2010 report, released September 9. "Most of these pollutants originate from combustion sources such as power plants, diesel trucks, buses and cars."

Of course, those are the same culprits contributing the bulk of greenhouse gas emissions. Yet "programs to scale up 'carbon neutral' energy are moving slowly at best," notes physicist Martin Hoffert of New York University in a perspective on the research also published in Science on September 10. "The difficulties posed by generating even [one terawatt] of carbon-neutral power led the late Nobel laureate Richard Smalley and colleagues to call it the 'terawatt challenge'."

That is because all carbon-free sources of energy combined provide a little more than two of the 15 terawatts that power modern society—the bulk of that from nuclear and hydroelectric power plants. At least 10 terawatts each from nuclear; coal with carbon capture and storage; and renewables, such as solar and wind, would be required by mid-century to eliminate CO2 emissions from energy use. As Caldeira and his colleagues wrote: "Satisfying growing demand for energy without producing CO2 emissions will require truly extraordinary development and deployment of carbon-free sources of energy, perhaps 30 [terawatts] by 2050."

------------------
NOTE:
(
POINT OF NO RETURN
<MW>
1941
1 : the point in the flight of an aircraft beyond which the remaining fuel will be insufficient for a return to the starting point with the result that the craft must proceed
2 : a critical point at which turning back or reversal is not possible
<Wiki>
en.wikipedia.org/wiki/Point_of_no_return
The point of no return is the point beyond which someone, or some group of people, must continue on their current course of action, either because turning back is physically impossible, or because to do so would be prohibitively expensive or dangerous.
<princeton>
wordnetweb.princeton.edu/perl/webwn
Rubicon: a line that when crossed permits of no return and typically results in irrevocable commitment
--------------------
The term PNR—"point of no return," more often referred to by pilots as the "Radius of Action formula"—originated, according to the Oxford English Dictionary, as a technical term in air navigation to refer to the point on a flight at which, due to fuel consumption, a plane is no longer capable of returning to its airfield of original takeoff. After passing the point of no return, the plane has no option but to continue to some other destination. In this sense, the phrase implies an irrevocable commitment.[1]
For nonstop flights between two definite locations, the PNR is actually beyond the halfway (more exactly, the "equitime") point, since aircraft usually carry more fuel than is necessary to reach the destination. For example, on a 2000-mile flight, should the tanks have enough fuel for a 3000-mile flight, the halfway point would be at 1000 miles, but the PNR would be at more than 1500 miles.
Neither does the PNR correspond to the halfway point of fuel usage. With loss of mass due to fuel consumption, it takes less fuel for an aircraft to cover a given mileage. An aircraft might expend, say, 60% of its total fuel load before reaching the PNR. The PNR can be further extended in this manner by dropping unnecessary fuel tanks or ordnance.
Another aviation use is the point during the takeoff roll when there is no longer enough runway ahead of the airplane to stop safely; at this point, the aircraft is committed to taking off. (See also V1 speed.) In mountain aviation, the phrase is sometimes used in a completely different way to refer to the point at which the grade of the terrain "outclimbs" the aircraft—that is, the point at which a crash is inevitable, being a parallel in common usage. The phrase can also be used in this sense to denote inevitable disaster.
The first major metaphorical use of the term in popular culture was John P. Marquand's novel "Point of No Return" (partially serialized in 1947, published in book form in 1949). It inspired a 1951 Broadway play of the same name by Paul Osborn. The novel and play concerned a pivotal moment in the life of an American banker, but they also explicitly referenced how the original expression was used in World War II aviation.
Since then, "point of no return" has become an everyday expression, with its aviation origins probably unknown to most speakers. It has served as a title for numerous literary and entertainment works

FINE PARTICLES
Particulates, alternatively referred to as particulate matter (PM) or fine particles and also called soot, are tiny subdivisions of solid or liquid matter suspended in a gas or liquid. In contrast, aerosol refers to particles and the gas together. Sources of particulate matter can be man made or natural. Air pollution and water pollution can take the form of solid particulate matter, or be dissolved.[1] Salt is an example of a dissolved contaminant in water, while sand is generally a solid particulate.
)

lghscuUID: 2552043

http://www.scientificamerican.com/article.cfm?id=quantum-light-switch
From the September 2010 Scientific American Magazine | 9 comments
Quantum Light Switch: Single Atom Acts as a Transistor for Photons
Demonstration that an atom can control the passage of light could be crucial in quantum computing and communications
By Davide Castelvecchi   

Point two laser beams so that they cross each other, and each goes through as if the other one did not exist. Light rays cannot interact with other light rays—or can they? With the help of a single atom, physicists have devised a system in which one light beam can turn another on or off. Such a light switch could serve as the basic component of futuristic optical quantum computers and may help open the way to a quantum version of the Internet, which would offer unbreakable data security.(背景式过渡开头，引出light beams新原理、新用途与特点。期待作者如何介绍原理与用途，当然一个新生儿肯定存在缺陷，一篇优秀的文章应该考虑全面，我们拭目以待)

The device makes use ofa phenomenon called electromagnetically induced transparency, in which a laser beam can render opaque clouds of atoms temporarily transparent to a narrow wavelength of light. The cloud can then act as a switch for a second beam, either letting it through or blocking it. The result is similar to what happens with transistors in electronic circuits, where a voltage applied at one electrode controls whether current can flow between two other electrodes.(粗略介绍laser beam用于switch的原理，并以大家熟悉的transistor作比较性说明。本段组织结构采用先new后old，这与OWL写作指导相背。当然，写作并不一定局限于特定框架，只要能够合理表达思想即可)

Applications such as quantum computing demand the control of beams down to single photons, the elementary particles of light. For that purpose, single atoms are better than clouds of them, says physicist Martin Mücke of the Max Planck Institute for Quantum Optics in Garching, Germany. He and his collaborators trapped a rubidium atom and aimed two different laser beams at it: one for probing, or transmitting, and the other one for switching. Ordinarily the atom acts as a barrier to photons from the probe beam because it would first absorb them—going from its “ground” state to an “excited” state—and then shoot them back, that is, reflect them. This condition would constitute the “off” state of the device.(通过实验具体介绍switch-off原理。这种写法值得借鉴：从上段的general到本段的specific。也就是写作手法一般为：从旧到新，从一般到具体)

But turning on the switching beam changed the atom’s possible states, so that it now had two different ground states. The probe beam then had two different ways of exciting the electron, each starting from a different ground state, but in the math ematics describing the atom’s quantum-mechanical nature, the two possibilities cancel out, so that no excitation was possible. Thus, the probe beam photons, rather than being absorbed, could get through, marking the “on” state.(具体介绍switch-on原理。本段transitions的运用很有特点)

Making single photons interact can be useful because a photon can carry the units of quantum information, called qubits. They can exist in two states simultaneously and thereby represent both the 0 and 1 of binary code at the same time. Thanks to this feature, quantum computers could perform certain operations in parallel. In principle, they could quickly perform calculations that a typical computer could not do, at least not before the sun swells up and bakes the earth five billion years from now.(优势明显)

Max Planck’s Gerhard Rempe, the senior researcher on the team, points out that a single-atom device could do more than mere switching. For example, it could store photons and release them at will without damaging their delicate quantum states—an application known as quantum random-access memory, which could be crucial for data routers of a quantum Internet. In such a network, privacy is guaranteed by the law of quantum physics [see “Privacy and the Quantum Internet,” by Seth Lloyd; Scientific American, October 2009].(多用途使得其前景光明)

The new device still needs improvement: in the off position, the atom still lets through 80 percent of photons from the second beam. But the researchers say that straightforward improvements, such as keeping the atom colder, could bring that number down to 10 percent, if not to 0. (A more substantial limitation is that handling single atoms requires a fairly sophisticated physics laboratory.) The team published its results in the June 10 Nature. (Scientific American is part of Nature Publishing Group.) Right now the device’s low efficiency limits its usefulness, comments Paul G. Kwiat, a quantum optics expert at the University of Illinois at Urbana-Champaign. But if the team can improve efficiency, he notes, it “could open a new, potentially efficient approach to quantum computing.”(作者行文思路确实值得学习：回答了首段读者的“缺陷”疑问，回答的过程是那么的巧妙--承认缺陷，但更强调科学家有希望克服缺陷，结果留给读者对此新技术的无限积极期待！！佩服！！！)

lghscuUID: 2552043

http://www.economist.com/node/16990766

Bacteria and climate change
Invisible carbon pumps
A group of oceanic micro-organisms just might prove a surprising ally in the fight against climate change
Sep 9th 2010 | Shanghai

UNDERSTANDING how the oceans absorb carbon dioxide is crucial to understanding the role of that gas in the climate. It is rather worrying, then, that something profound may be missing from that understanding. But if Jiao Nianzhi of Xiamen University in China is right, it is. For he suggests there is a lot of carbon floating in the oceans that has not previously been noticed. It is in the form of what is known as refractory dissolved organic matter and it has been put there by a hitherto little-regarded group of creatures called aerobic anoxygenic photoheterotrophic bacteria (AAPB). If Dr Jiao is right, a whole new “sink” for carbon dioxide from the atmosphere has been discovered.(提出新理念--AAPB & carbon dioxide & climate change)

The main way that carbon dioxide is absorbed by the ocean is through photosynthesis by planktonic algae. These algae are the basis of most food chains in the sea—being eaten by tiny animals that are, in turn, eaten by larger ones. When all these creatures die, their remains (those bits that are not immediately eaten, anyway) sink to the sea floor, where some are eaten and some are buried indefinitely. These remains are known in the jargon as particulate organic matter. (概述photosynthesis在carbon dioxide cycle中的机制)

Some of the organic compounds the dead creatures contain, though, dissolve out of them and into the water. This dissolved organic matter was not, until recently, thought to be an important component of the total. But Dr Jiao noticed something odd about its distribution in the sea. It would be expected to correlate with the distribution of planktonic algae—the ultimate drivers of biological productivity. But it does not. (缺陷所在--认识误区，考虑不周)

The reason, it turned out, was that previous researchers had been tracking only a small fraction of the total—the portion composed of molecules such as sugars and L-amino acids that can be metabolised easily by living things. They had missed a whole host of molecules that cannot easily be metabolised. These included D-amino acids, which are mirror images of the L-variety normally found in living things, and compounds called porins, lipopolysaccharides and humic acids. Because they are not metabolised, these molecules are referred to as “refractory”. Only when this refractory material is taken into account does the chemical map match the planktonic one.(缺陷原因分析，铺垫进入refractory介绍)

A refractory puzzle
The reason this matters is that 95% of dissolved organic matter seems to be refractory. Dr Jiao estimates that the amount of carbon stored by the oceans in this way is equal to the amount in the atmosphere, in the form of carbon dioxide.(如此假设是新理念核心)

It was discovered ten years ago that AAPB produce refractory molecules when they metabolise sugars and L-amino acids, but it is only recently that the scale on which they do so has become apparent. That started happening in 2006, when Dr Jiao developed a technique called time-series observation-based infra-red epifluorescence microscopy, or TIREM for short, that is able to measure the amount of AAPB in the oceans accurately. (对上述假设进一步论证，general-->specific)

TIREM has shown that AAPB are ubiquitous, and constitute 7% of the oceans’ microbes. Moreover, they grow up to five times faster than typical bacteria—in part because, as the “photoheterotrophic” in their name suggests, they can both photosynthesise and derive nutrition from the remnants of other organisms. Which is more important to them, though, was not clear until Dr Jiao and his colleagues began their research. After sampling waters from the Pacific, Atlantic and Indian oceans at all latitudes, they found that the amount of AAPB in the water is controlled mainly by the level of planktonic algae in the region, rather than by the amount of light. They therefore suspect the main source of food for AAPB is dissolved organic matter released by phytoplankton. The question is, how is some of this converted into refractory compounds?(指出AAPB存在两方面特点，以produce refractory compounds)

It is possible that AAPB release such compounds during their normal metabolism. That would be odd, though, since it would be a waste of valuable carbon. Instead, Dr Jiao thinks refractory compounds are made and released by these bugs mainly in response to viral infections. Indeed, he has found that AAPB are particularly prone to such infections and his team have isolated a virus that seems to be specific to this type of bacterium. At the final stage of the infection, the viruses destroy the cells they have infected, a process that provides a rich source of refractory compounds.(回答上段疑问)

Based on these findings, Dr Jiao and his colleagues propose that AAPB, and possibly other, similar microbes, have a predominant role in pumping carbon into a pool of compounds that cannot be turned back into carbon dioxide by living creatures, thereby building up a large reservoir that keeps carbon out of the atmosphere. If that idea is confirmed, it will need to be incorporated into the computer models used to understand the Earth’s carbon cycle and its effect on the climate. But it also raises a more radical thought. The newly discovered microbial carbon pump could provide a novel way to extract CO2 from the atmosphere, should that ever be deemed necessary to combat climate change. (AAPB-->refractory compounds-->climate change这是一个漫长的过程，至此作者才完全丢出题目核心)

At the moment, the most plausible way of making the sea absorb more of the gas is to seed it with iron. A lack of this metal is commonly the brake that stops the growth of planktonic algae. Experiments that add iron to the sea have had mixed success, though, and may cause harmful algal blooms and ocean acidification. If AAPB could be recruited, they would provide an alternative way of getting the sea to lock up CO2. How that might be done is obscure at the moment, for the organisms are still barely understood. Moreover, there would surely be side-effects to stimulating their activity. Those side-effects, though, might be more bearable than the ones associated with iron seeding. Only further research can find that out. (客观性论述：新方法缺陷)

In the meantime, there are many questions to answer. For example, Dr Jiao and his colleagues want to map the abundance, composition and distribution of refractory molecules in more detail. They want to understand what makes such compounds refractory and whether they can be made more or less so. They also want to know exactly how viral infections stimulate production of the molecules.(T-I-I结构展望未来work)

To address these questions, scientists from China and elsewhere are rushing around the oceans from ice-cold polar regions to the Indo-Pacific Warm Pool, the warmest marine waters in the world. If progress can be made, this curious discovery may turn out to be a powerful ally in the fight against global warming.(呼应题目，表达一种积极态度)

lghscuUID: 2552043

Write at an Appropriate Level of Difficulty
It is essential that you write at an appropriate level of difficulty in order to clearly
convey your message. Consider your audience and prepare your writing so that the
reader will clearly understand what it is that you are saying. In other words,
prepare your style of reading to match the reading abilities of your audience. Do
not use complex passages or terms that the reader will not understand.
Accordingly, do not use simple terms or insufficient examples if the reader is
capable of understanding your writing. A competent writer will match the needs
and abilities of their reader and find the most effective way to communicate with a
particular reader.

-Tone in Business Writing
http://owl.english.purdue.edu/

Colin_hUID: 2855722

LZ好努力啊，膜拜一下
加油

lghscuUID: 2552043

http://www.scientificamerican.com/article.cfm?id=doubts-on-dinosaurs


May 16, 2005 | 1 comments
Doubts on Dinosaurs
Yucatán impact crater may have occurred before the dinosaurs went extinct
By Barry E. DiGregorio   

According to conventional paleontological wisdom, an asteroid or comet 10 to 14 kilometers wide crashed into the present-day Yucatán Peninsula 65 million years ago and wiped out the dinosaurs. Most scientists currently consider the Chicxulub impact crater, perhaps about 145 kilometers wide, to be the smoking gun of this Cretaceous-Tertiary (KT) extinction. (观点对比：conventional vs currently，但共同点在于impact-->cinosaur extinction)

Not so fast, says Princeton University micropaleontologist Gerta Keller. The collision that created the Chicxulub crater, she argues, happened before the KT extinction--300,000 years too soon, to be more precise. She first made the controversial assertion last year, and the dust has yet to settle. (有冲突才有探讨价值，写作亦如此)

Keller does not dispute that a meteorite could have helped trigger the demise of the dinosaurs. But she remains confident that Chicxulub is not the crater scientists should be looking at, based on sediments she has analyzed from various Chicxulub sites. She has several lines of evidence: one in particular relates to the layer of iridium, an extremely rare element known to be abundant in many meteorites, that exists at the KT boundary at sites around the world. In theory, only massive impacts can distribute the element globally. (陈述doubt理由一)

A big collision can also produce another kind of layer, too, by melting and vaporizing silicate rocks, which then condense into sand-grain-size glass spheres known as microtektites. Depending on the mass of the colliding meteorite, these tiny glass spheres can be thrown hundreds to thousands of kilometers from the point of impact.

Keller discovered that the original Chicxulub microtektite layers lie up to 14 meters below the KT iridium layer at the northeastern Mexico site (the crater itself extends from the northwestern tip of the Yucatán Peninsula into the Gulf of Mexico). "To date, no one has found iridium associated with Chicxulub," Keller says. (陈述doubt理由二)

Jan Smit, a paleontologist at Vrije University in the Netherlands, doubts Keller's claims, stating that her argument about KT iridium and Chicxulub borders on tautology: "If you uncouple all the iridium-enriched ejecta layers from the Chicxulub impact, then of course there is no iridium associated with Chicxulub." In any case, Smit contends, "How and where do you hide the iridium from a large impact such as Chicxulub?" (互相argue)

Keller hypothesizes that the object that made Chicxulub may have been "a dirty snowball" type that did not have any iridium. Some meteorites do not. Another possibility could be that measurements may not yet have been taken from the correct rock strata.(argue)

Researchers have also raised doubts about Keller's proposed 300,000-year age difference between Chicxulub and KT, which is based on sedimentation rates extrapolated from the distance between the microtektite layer and the KT boundary layer. Geoffrey Garrison, a paleontologist from the University of Washington, wonders why the material separating the two layers could not have been just sediment that was resuspended by the impact and that had simply settled back to the seafloor. (argue)

Keller insists that she has already ruled out resuspension. She claims that sediment settling after a high-energy event, such as an impact, tsunami or storm, produces identifiable layers. Heavier grains settle out first, followed by the finest-grained muds and clays. Such a pattern does not appear in the Chicxulub crater, Keller reports. (argue: 作者长短句式的运用暗示读者其立场)

Keller plans to bolster her case with an upcoming paper that argues that meteorite impacts that leave Chicxulub-size craters and smaller cannot by themselves cause significant species extinctions. The amount of material ejected, she finds, is insufficient to trigger long- lasting climatic or geographic changes from fire or floods. Sudden mass extinctions might require the coincidence of major volcanism and a large impact event, "but so far no one has found the source crater," Keller says in her dismissal of Chicxulub. "The history of mass extinctions seems to indicate that a single short-term shock to the environment can be survived by nearly all species." Whether conventional wisdom survives Keller's own shock to paleontology remains to be seen.(作者的立场比较明显地偏向于Keller。最后一句点题remains to be seen-->doubt on dinosaurs)
---------------------
NOTE:
smoking gun
<MW>
: something that serves as conclusive evidence or proof (as of a crime or scientific theory)

wordnetweb.princeton.edu/perl/webwn
: indisputable evidence (especially of a crime)

en.wikipedia.org/wiki/The_Smoking_Gun
: The Smoking Gun is a website that posts legal documents, arrest records, and police mugshots on a daily basis. The intent is to bring to the public light information that is damning, shocking, outrageous, or amazing, yet also somewhat obscure or unreported by more mainstream media sources. ...

lghscuUID: 2552043

http://www.scientificamerican.com/article.cfm?id=depression-drugs-alter-personality
From the September 2010 Scientific American Mind | 7 comments
Depression Drugs Affect Personality
Less neuroticism and more extroversion may be at the root of patients' improvement
By Allison Bond   
Friends and family of people with depression may feel that their loved one has been replaced by a gloomy doppelg&auml;nger. According to recent research, however, it may be the treatment of depression that actually causes personality changes in people with the disorder.

Experts have long known that the placebo effect explains much of the mood lift patients report after going on antidepressants. This was the case in the new study, published in the journal Archives of General Psychiatry—patients with major depressive disorder who were given a placebo saw their symptoms im prove about three quarters as much as those given paroxetine, an antidepressant also known as Paxil. But only the patients who took parox etine displayed personality changes in two key areas of the widely used five-factor model of personality: they scored lower on neuroti cism, the tendency to experience negative emotions such as guilt and anxiety, and they scored higher on extroversion, which includes traits such as talkativeness and assertiveness.

Personality traits are thought to be relatively stable over a person’s life—even the onset of depression, which comes with unusually low moods, should not alter a person’s fundamental traits. Personality can affect a person’s risk for mental illness, however—past research has established neuroticism as a key risk factor for depression, explains Tony Tang of Northwestern University, the lead author of the study. Tang and his colleagues found that the more a patient’s neuroticism dropped while taking paroxetine, the smaller the chance that his or her depression would return after they stopped taking the drug.

The study “proves in an elegant way that antidepressant medications and placebo have different actions in many cases,” says Andrew Leuchter, a depression researcher at the Univer sity of California, Los Angeles, who was not a part of the study. “This may explain in part some of the ways that antidepressants have a thera peutic benefit for some patients.”

==================================================================

From the October 2008 Scientific American Mind | 1 comments
Your iBrain: How Technology Changesthe Way We Think ( Preview )
How the technologies that have become part of our daily lives are changing the way we think
By Gary Small and Gigi Vorgan   
Key Concepts

• The brain’s plasticity—its ability to change in response to stimuli from the environment—is well known. What has been less appreciated is how the expanding use of technology is shaping neural processing.
• Young people are exposed to digital stimulation for several hours every day, and many older adults are not far behind.
• Even using a computer for Web searches for just an hour a day changes the way the brain processes information. A constant barrage of e-contacts is both stimulating—sharpening certain cognitive skills—and draining, studies show.

You’re on a plane packed with other businesspeople, reading your electronic version of the Wall Street Journal on your laptop while downloading files to your BlackBerry and organizing your PowerPoint presentation for your first meeting when you reach New York. You relish the perfect symmetry of your schedule, to-do lists and phone book as you notice a woman in the next row entering little written notes into her leather-bound daily planner. You remember having one of those ... What? Like a zillion years ago? Hey, lady! Wake up and smell the computer age. You’re outside the airport now, waiting impatiently for a cab along with dozens of other people. It’s finally your turn, and as you reach for the taxi door a large man pushes in front of you, practically knocking you over. Your briefcase goes flying, and your laptop and BlackBerry splatter into pieces on the pavement. As you frantically gather up the remnants of your once perfectly scheduled life, the woman with the daily planner book gracefully steps into a cab and glides away.

The current explosion of digital technology not only is changing the way we live and communicate but also is rapidly and profoundly altering our brains. Daily exposure to high technology—computers, smart phones, video games, search engines such as Google and Yahoo—stimulates brain cell alteration and neurotransmitter release, gradually strengthening new neural pathways in our brains while weakening old ones. Because of the current technological revolution, our brains are evolving right now—at a speed like never before.

http://www.scientificamerican.com/article.cfm?id=the-effect-of-our-surroundings-on-body-weight

lghscuUID: 2552043

http://www.scientificamerican.com/article.cfm?id=baby-boy-early-development-may-predict-young-man-success

September 14, 2010 | 3 comments
Man-Made: A Baby Boy's Development May Predict a Young Man's Success
Early childhood nutrition may play a role in determining the stature and masculinity of young men, suggests a study that began in 1983
By David Biello   

You are what your mother fed you, especially if you are a young man. A new study that looked at the height, weight, muscle mass, strength, testosterone levels and even sexual history of 770 Filipino men tracked from birth reveals that the degree of a baby boy's growth in the first six months of life predicts the extent of his masculine characteristics.

This period is crucial because it is "when testosterone is at roughly adult levels," explains biological anthropologist Christopher Kuzawa of Northwestern University, who led the study published online September 14 in Proceedings of the National Academy of Sciences. "Men who as babies gained weight rapidly during the period of this testosterone surge matured earlier, were taller, had more muscle, were stronger and had higher testosterone levels. Because they matured earlier, not surprisingly, they started having sex for the first time at a younger age and had more sex partners."

That's pretty much the recipe for success from an evolutionary standpoint, and it also provides evidence as to how nurture might shape an underlying nature. After all, this testosterone surge in early life contributes to the male characteristics of many mammals. "The things that define males are flexible characteristics in response to nutrition," Kuzawa argues. "Your fate is not hardwired."

Kuzawa and his colleagues conducted follow-up interviews with 770 Filipino men whose mothers had enrolled in 1983 in the Cebu Longitudinal Health and Nutrition Survey, a cross-section of the population of the Philippine's second-largest city. The researchers looked at growth data from the boys' first two years of life as well as information collected when they were eight, 11 and 14. Finally, the researchers interviewed the men in their early 20s.

Those boys who had grown the fastest from birth to six months, who generally were also the boys who were breast-fed and grew up in wealthier homes, became the men exhibiting the most masculine characteristics. A similar analysis of 690 Filipino women revealed no such difference (Kuzawa is now conducting a follow-up study to see if there are any long-term effects of early nutrition on the birth weight of these women's offspring.)

That discrepancy could be because the testosterone surge literally shapes the bodies of men, including organs and bones. The "environment" the baby boys encounter—most important, the nutritional environment—then governs the size of the surge. "The slow growers are undernourished and nutrition-stressed," Kuzawa notes.

Of course, the researchers could simply be demonstrating the effects of nutrition on male development—or even the effects of breast-feeding. "There may be factors in the mother's breast milk, but we don't have the ability to actually look at that," Kuzawa notes. But he adds that the effect in humans matches the same biological pattern found in other animals, such as rats. "If nutrition is better, they can afford more of those traits, and under more limiting nutrition circumstances it might benefit that individual not to commit to that kind of costly body."

But the effects of socioeconomic class and culture are hard to rule out as well. The richest boys also grew fastest throughout the entire first two years. "We are seeing overwhelmingly an effect of poverty as an influence on outcomes," Kuzawa says, although cautioning on extrapolating from one specific set of circumstances in the Philippines to any other country. "We can't predict how these findings play out in a population," he says of the U.S., for example, "where the fastest growers are actually gaining too much weight."

lghscuUID: 2552043

http://www.scientificamerican.com/article.cfm?id=undifferentiatied-ethics

From the September 2010 Scientific American Magazine | 22 comments
Undifferentiated Ethics: Why Stem Cells from Adult Skin Are as Morally Fraught as Embryonic Stem CellsHailed as a potential alternative to embryonic stem cells, induced pluripotent stem cells (iPS cells) raise their own ethical dilemmasBy Sally Lehrman   

ADULT STEM CELLS: These blue cells are human mesenchymal stem cells that have become senescent—or lost the ability to divide—after X-ray irradiation.
Lawrence Berkeley National Laboratory

San Francisco— When researchers first demonstrated in 2007 that human skin cells could be reprogrammed to behave like stem cells that can fully differentiate into other cells, scientists and politicians alike rejoiced. All the potential of embryonic stem cells might be harnessed with the new techniques—without the political and moral controversy associated with destroying a fertilized egg.
That optimism, however, may be misplaced; these transformed cells, known as induced pluripotent stem cells (iPS cells), actually present equally troubling ethical quandaries, according to bioethicists who met at the International Society for Stem Cell Research annual meeting in June. Not only do many of the ethical challenges posed by embryonic stem cells remain, but the relative ease and low cost of iPS techniques, combined with the accessibility of cells, accelerate the need to address futuristic-sounding possibilities such as creating gametes for reproduction. Scientists have already reported progress in growing precursor cells for eggs and sperm from both iPS and embryonic stem cell lines.
Although perfecting the process may take another decade, “we should start thinking carefully about this now,” said Kazuto Kato, a bioethicist at Kyoto University in Japan. To make sure the gametes work normally, for instance, researchers will need to grow embryos and then destroy them, a morally contentious practice with prohibitions and policies differing around the world. Sperm and egg from skin cells eventually might be used for reproductive purposes, enabling parenthood at any age using tissue from either the living or dead. In fertility clinics, iPS cells could enable prospective parents to choose embryos for desired traits more easily than they can with conventional assisted-reproduction technologies. The possibilities raise a radical question about the moral status of human cells, noted Jan Helge Solbakk, head of research at the Center for Medical Ethics at the University of Oslo in Norway and chair of the society’s ethics and public policy committee.
Although Kato called human reproductive cloning directly from iPS cell lines “very hypothetical,” he pointed out progress for that possibility when he noted that three teams had produced mouse clones from iPS cells. Less expensive and more efficient than the process that produced Dolly the sheep, the iPS approach also would skirt the language of many current prohibitions against human reproductive cloning. Some bioethicists have called for a new international ban that would clearly prohibit the implantation of a human clone in part because of the tantalizing research uses for nascent embryos.
More immediate concerns have to do with control of the original donation and tissue grown from iPS cells. “Biobanks” all over the world already store biological material and related data for research, and many do not seek consent for future work as long as the material cannot be connected back to the donor. The far-reaching potential of iPS research, combined with a higher likelihood that cell lines will stay linked to a single donor (and that donor’s health history), heightens the need for consensus, said Timothy Caulfield, research director of the Health Law Institute at the University of Alberta in Edmonton.
Yet such consensus may be hard to achieve. In research on attitudes, Caulfield has noticed a trend: clinical researchers, patient participants, privacy experts and the general public disagree about whether consent should be necessary for each new use of donated tissue or whether blanket consent will do. And how will a disillusioned cell donor withdraw when iPS cell lines have been distributed all over the world? Bedrock international research norms of consent and withdrawal may no longer be workable. “We have to recognize all the complicated issues that iPS research is engaging and get a sense of how existing laws and policies play out,” Caulfield said.

Some ethicists suggest that tissue donors deserve a share of the tremendous commercial potential of iPS cell lines as disease models, drug-testing platforms or treatments. New partnerships could acknowledge the contributions of both the cell provider and the laboratories that grow and sustain iPS cell lines. Donors might share in some monetary rewards and be able to opt out of certain uses for iPS cells, such as for creating gametes or mixed species, or have a say in the overall direction of research, Solbakk suggested.
The stem cell society’s ethics committee is working on a paper that would explore the rights of tissue donors and make recommendations by the end of the year. Solbakk also hopes to hold more public forums that could clarify research advances while also stimulating reflection on ethical challenges. He said the society would continue its efforts to reduce hype in the field. A new Web site aims to help patients evaluate claims by clinics that offer stem cell treatment and even submit a clinic for review by the society. “The most vulnerable resource,” Solbakk said, “is trust.”

lghscuUID: 2552043

http://www.economist.com/node/16984701
Sexual selection
Lord of the dance
The dance moves that make men attractive to women

Sep 8th 2010

THE need to identify a suitable mate is such a strong biological urge that the animal kingdom has spawned a bewildering array of courtship rituals. Hippo males fling their faeces; flatworms have penis-jousting contests; and humpback whales sing and leap above the ocean surface. Such competitive displays depend on the speed, strength and size of an animal, which is why they convey a measure of reproductive fitness.
Dancing is popular among animals for similar reasons. Scorpions and sandhill cranes, for instance, dance to impress. Humans also use dance as part of courtship, but it has been difficult for scientists to pin down exactly what it is about a dance that appeals to members of the opposite sex. This is because factors such as facial attractiveness, height and even social status tend to confound any attempt to judge the relative merits of a person’s gyrations.


Nick Neave of Northumbria University in Britain decided to try to answer the question using motion-capture technology, as used to make films like “Avatar”. Thirty students were recruited, none of whom was a professional dancer. They were covered in reflective markers, which allowed cameras to capture their dancing moves. A constant drum beat was provided and the students were asked to dance, but not told how.
Related items

Health and the sex ratio: A healthy relationshipAug 11th 2010 Sexual selection: The hunk and the show-off do not always get the girlJun 3rd 2010
• Sexual selection: Horny ladiesMar 4th 2010

The motion-capture data were used to animate a humanoid avatar that was featureless and gender-neutral. Heterosexual women were then asked to judge the quality of the dancing. The results, published in Biology Letters, were intriguing: the most attractive movements were those that had “variability and amplitude” in the head, neck and trunk.

Dr Neave explains that humans move in three planes. You can nod your head backwards and forwards, side to side or twist your neck to look over a shoulder. The women rated big movements in these three planes for both the head and the trunk as the most attractive. However, there was an additional factor, says Dr Neave. Head-banging (sorry, Mot&ouml;rhead fans) was simply not attractive: although it would show a large amplitude of movement in one plane it would not show the variability of movement that seems to appeal to women. Choreographers have told Dr Neave that movements in these three planes comes from strength and suppleness, so they would help to indicate a genetically fit male.
One curiosity was that, statistically, the speed of movement of the right knee also appeared to be important in signalling dance quality. Dr Neave, however, believes this may simply result from 80% of men being right footed, and so tending to place more weight on their left foot in order to demonstrate leg-waggling prowess with the right one.

Kristofor McCarty, a scientist who was also involved in the study, believes the work is the first scientific step towards understanding the biology and culture of dance. The scientists think that the core moves of an attractive dance may be universal, but that many cultures will have variations. For instance, in places where folk dances require the torso to be rigid, one would expect to find more emphasis put on the movement of the feet or head.

As for Dr Neave, he says that at 46 his dancing days are over. Nonetheless he remains interested enough to suspect that physically attractive males are better dancers and also wonders whether it is possible to detect a person’s age from the quality of their dancing. If he can recruit enough gay men, he would also like to see if they make better dancers.

And then there are the sexual signals from female dancers to explore. Dr Neave has started to look at women in high heels (in the scientific sense) and ask whether high-heeled avatars are more attractive to men. Some have speculated that the attractiveness of high heels is down to the youthful gait it gives women; others reckon it simply makes a woman’s bum wobble. Avatars, having no wobbly bits, should therefore be able to solve that perpetual male mystery: why do women buy shoes that they cannot walk in?

lghscuUID: 2552043

  OFFER for Ph.D. from Missouri S&T ... 1 2 3
https://bbs.gter.net/viewthread.php?tid=1213773&highlight=