MY AMERICAN SCIENTIST
LOG IN! REGISTER!
SEARCH
 
RSS
Logo IMG
HOME > SCIENCE IN THE NEWS

Science in the News

Quick and Cheap DNA Sequencing on the Horizon?

from Smithsonian

When the human genome was first sequenced about a decade ago, the achievement took years and cost $1 billion. Now, scientists and entrepreneurs are predicting that the task will soon take just under 6 hours, with a price tag of just $900. A company called Oxford Nanopore Technologies claims it will accomplish this feat using a device that can plug into your computer's USB port.

The key to this remarkable rate of progress? A technology called nanopore sequencing, which allows researchers to determine the sequence of base pairs in an individual's DNA without taking it apart.

Traditional DNA sequencing techniques involves making many copies of an individual's genome, cutting it into millions of small fragments, and using radioactively-labelled bases to determine the exact sequence of the four bases that make up DNA--adenine, guanine, cytosine and thymine, often abbreviated A, G, C and T. Currently, sequencing using advanced versions of this technique takes about a week and costs roughly $18,000. The equipment takes up a lab bench and requires technicians to process the DNA sample before and after sequencing.

Read more...

Save to Library

How the Scent of Fear May Be Picked Up by Others

from the New York Times (Registration Required)

When one fish is injured, others nearby may dart, freeze, huddle, swim to the bottom or leap from the water. The other fish know that their school mate has been harmed. But how?

In the 1930s, Karl von Frisch, the famous ethologist, noted this behavior in minnows. He theorized that injured fish release a substance that is transmitted by smell and causes alarm. But Dr. von Frisch never identified the chemical composition of the signal. He just called it schreckstoff, or "scary stuff."

Schreckstoff is a long-standing biological mystery, but now researchers may have solved a piece of it. In a study published in February in Current Biology, Suresh Jesuthasan, a neuroscientist at the Biomedical Sciences Institutes in Singapore, and his colleagues isolated sugar molecules called chondroitins from the outer mucus of zebra fish.

Read more...

Save to Library

Panel Advises Dropping PSA Test

A government task force made the controversial recommendation last week that the PSA test should be abandoned as a prostate cancer screening tool. The panel came to that conclusion after determining that the side effects from needless biopsies and treatments hurt many more men than are potentially helped by early detection of cancers.

In other biomedical news, a new study suggests that long-acting birth control devices are nearly 22 times as reliable as contraceptive pills or other short-acting approaches that need close monitoring.

Nearly one in four American adolescents may be on the verge of developing Type 2 diabetes or could already be diabetic, representing a sharp increase in the disease's prevalence among children ages 12 to 19 since a decade ago.

And, finally, the government proposed that all baby boomers get tested for hepatitis C. Anyone born from 1945 to 1965 should get a one-time blood test to see if they have the liver-destroying virus, the Centers for Disease Control and Prevention said in draft recommendations issued last week.

Save to Library

Arctic Methane: 'The Warming Will Feed the Warming'

There are thousands of sites in the Arctic where methane that has been stored for millennia is bubbling into the atmosphere. The methane has been trapped by ice, but is able to escape as the ice melts. Researchers say this ancient gas could have a significant impact on climate change.

In other environmental news, Los Angeles has become the largest city in the U.S. to approve a ban on plastic bags at supermarket checkout lines. The City Council voted to phase out plastic bags over the next 16 months at an estimated 7,500 stores, meaning shoppers will need to bring reusable bags or purchase paper bags for 10 cents each.

Periodic increases in the flow of Colorado River water through the Grand Canyon are designed to alleviate the environmental disruption caused by the construction of the Glen Canyon Dam in Arizona in the 1960s. By mimicking the river's original dynamics, federal officials said, the flows could help restore the backwater ecosystems in which native fish are most at home.

A pan-European project has devised a much-anticipated way to differentiate marine populations of the same species with up to 100% accuracy. It will help managers tell the difference between, for example, an illegally harvested Northeast Arctic cod and a perfectly legal Eastern Baltic cod. The new approach relies on genetic variants called single-nucleotide polymorphisms.

An autonomous robotic fish designed to sense marine pollution is lurking in the waters of the port of Gijon, Spain. The robots will continuously monitor the water, letting the port respond immediately to the causes of pollution, such as a leaking boat or industrial spillage, and work to mitigate its effects.

Scientists have concluded that fresh water demand is driving sea-level rise faster than glacier melt. The massive impact of the global population's growing need for water on rising sea levels is revealed in a comprehensive assessment of all the ways in which people use water.

Save to Library

A Promising Advance in Dye-Sensitized Solar Cells

Solar cells could become much cheaper thanks to improvements in a more than 20-year-old solar technology that captures light with dye molecules. The advance is "one of the most important breakthroughs in dye cells in the last several years," says a chemist at Pennsylvania State University, University Park.

In other technology news, two researchers at the New Jersey Institute of Technology (N.J.I.T.) have devised a direct-contact membrane distillation (DCMD) system that can efficiently wring drinking water out of up to 20 percent-salt-concentrated brine.

Two scientists at Northwestern University in Evanston, Illinois, have designed a metamaterial that stretches when compressed, and vice versa, under any circumstances. "What is interesting is that they study systems that are not responding to a vibration but to a steady applied force," says John Pendry of Imperial College London.

As a Houston computer scientist has developed his ideas over nearly a decade, he has found increasing acclaim for his "inexact" computer chips. At a major computing conference in Italy, Rice University's Krishna Palem unveiled his newest chips that trade a bit of accuracy for better efficiency.

When Clarence Birdseye figured out how to pack and freeze haddock, using what he called "a marvelous new process which seals in every bit of just-from-the-ocean flavor," he essentially changed the way we produce, preserve and distribute food.

Save to Library

Disputed Fossil Sold for $1 Million

An American auction house sold a fossil of a fearsome T. rex relative for $1 million despite a court order not to. The fossil was found in Mongolia, and the sale is contingent on the outcome of a court fight with the Mongolian government over ownership.

In other news of the ancient past, scientists have for the first time confirmed pigment in two fossilized ink sacs from cuttlefish-like animals, a new study says. The ancient ink's similarity to modern squid ink suggests that this defensive weapon hasn't evolved much since the Jurassic period.

The consensus is that dogs came from wolves. Beyond that, there are varying claims. It seems dogs appeared sometime between 15,000 and 100,000 years ago, in Asia or Africa or multiple times in multiple places. In a new study, a researcher argues that the DNA of modern dogs is so mixed up that it is useless in figuring out when and where dogs originated.

A team of paleontologists has discovered the fossil remains of a new species of dining-table-size freshwater turtle that apparently lived side-by-side with the 50-foot snakes and super-size crocodiles that they had found earlier in the same Colombian coal mine.

Save to Library

Falcon 9 Launch Successful

A private cargo rocket built by Space Exploration Technologies Corp. of Hawthorne, Calif. blasted off last week, headed to the International Space Station. The rocket carried only about 1,000 pounds of cargo. The importance of the launch was more technical and symbolic.

In other space news, stargazers will have a chance on June 5 to glimpse a transit of Venus, in which the planet passes directly between Earth and the sun. Venus will take six hours to march across the star's face, appearing as an inky black dot in silhouette against the solar disk.

The moon nearly blotted out the sun last week, creating a blazing "ring of fire" eclipse visible in many parts of the world.

In 2019, a spacecraft known as Euclid will begin a mission to study dark energy. But it is being launched by the European Space Agency, not NASA, with American astronomers serving only as very junior partners.

Save to Library

The Roar of the Crowd

from the Economist

ACCORDING to Joseph Henrich and his colleagues at the University of British Columbia, most undergraduates are WEIRD. Those who teach them might well agree. But Dr Henrich did not intend the term as an insult when he popularised it in a paper published in Behavioral and Brain Sciences in 2010. Instead, he was proposing an acronym: Western, Educated, Industrialised, Rich and Democratic.

One reason these things matter is that undergraduates are also psychology's laboratory rats. Incentivised by rewards, in the form of money or course credits, they will do the human equivalents of running mazes and pressing the levers in Skinner boxes until the cows come home.

Which is both a blessing and a problem. It is a blessing because it provides psychologists with an endless supply of willing subjects. And it is a problem because those subjects are WEIRD, and thus not representative of humanity as a whole. Indeed, as Dr Henrich found from his analysis of leading psychology journals, a random American undergraduate is about 4,000 times more likely than an average human being to be the subject of such a study. Drawing general conclusions about the behaviour of Homo sapiens from the results of these studies is risky.

Read more...

Save to Library

Trading: What Impact Will Facebook Have on Organ Donations?

from Scientific American

Since launching in February 2004, Facebook has proved highly effective at creating opportunities for the average Web user to create campaigns that reach a mass audience. Most recently such opportunities have extended to organ donation, an area that could benefit from the social network's attention--controversy over its recent initial public offering aside, Facebook's membership is more than 900 million and growing.

Indeed, with demand for healthy organs for transplantation growing worldwide, Facebook has already become a popular channel for people soliciting kidneys, livers and other potentially lifesaving organs. Earlier this month the social network began offering members the ability to identify themselves as organ donors on their Facebook pages and to locate state organ-donation registries if they would like to become donors.

Last October a team of researchers at Loyola University Medical Center began tracking how Facebook was being used as a tool for connecting potential donors with those in need of an organ. The researchers focused on kidney solicitations in particular and studied 91 Facebook pages seeking kidney donations for patients ranging in age from two to 69. Of the Facebook pages studied, 12 percent reported receiving a kidney transplant and 30 percent reported that potential donors had stepped forward to be tested to determine whether they were compatible, the researchers recently reported at a meeting of the National Kidney Foundation. One page reported that more than 600 people had been tested as potential donors for a young child.

Read more...

Save to Library

Anarchists Attack Science

from Nature News

A loose coalition of eco-anarchist groups is increasingly launching violent attacks on scientists.

A group calling itself the Olga Cell of the Informal Anarchist Federation International Revolutionary Front has claimed responsibility for the non-fatal shooting of a nuclear-engineering executive on 7 May in Genoa, Italy. The same group sent a letter bomb to a Swiss pro-nuclear lobby group in 2011; attempted to bomb IBM's nanotechnology laboratory in Switzerland in 2010; and has ties with a group responsible for at least four bomb attacks on nanotechnology facilities in Mexico. Security authorities say that such eco-anarchist groups are forging stronger links.

On 11 May, the cell sent a four-page letter to the Italian newspaper Corriere della Sera claiming responsibility for the shooting of Roberto Adinolfi, the chief executive of Ansaldo Nucleare, the nuclear-engineering subsidiary of aerospace and defence giant Finmeccanica. Believed by authorities to be genuine, the letter is riddled with anti-science rhetoric. The group targeted Adinolfi because he is a "sorcerer of the atom," it wrote. "Adinolfi knows well that it is only a matter of time before a European Fukushima kills on our continent. Science in centuries past promised us a golden age, but it is pushing us towards self-destruction and total slavery. With this action of ours, we return to you a tiny part of the suffering that you, man of science, are pouring into this world." The group also threatened to carry out further attacks.

Read more...

Save to Library

Polio's Last Stand

from Nature News

A hard-fought battle against the polio virus may be approaching its endgame. Last week, health officials laid out plans to eradicate the virus from its last redoubts, but warned that the effort may founder owing to a US$1-billion funding gap.

"We are truly at a tipping point in the programme right now," says Bruce Aylward, an assistant director-general at the World Health Organization, who is leading the eradication effort. Speaking at the 65th World Health Assembly in Geneva, Switzerland, he announced an Emergency Action Plan to step up vaccination efforts in the three countries that have never been able to stop the virus from spreading: Nigeria, Afghanistan and Pakistan.

The plan, which would boost global spending to $2.2 billion over the next two years, aims to stamp out new polio cases by the end of this year. Some experts believe it will take longer, but they agree that the push will eventually deliver victory to the Global Polio Eradication Initiative (GPEI), a $9-billion campaign that began in 1988, a time when an estimated 350,000 people succumbed to polio each year. The initiative, based in Geneva, made rapid gains in the Americas, Europe and parts of Asia, but since 2001, incidence rates have plateaued, with 1,000-2,000 people developing poliomyelitis each year worldwide.

Read more...

Save to Library

New Study Sounds Warning on Hormone Replacement Therapy

from the Washington Post (Registration Required)

Women who are past menopause and healthy should not take hormone replacement therapy in hopes of warding off dementia, bone fractures or heart disease, according to a new analysis by the government task force that weighs the risks and benefits of screening and other therapies aimed at preventing illness.

The recommendation by the U.S. Preventive Services Task Force does not necessarily apply to women who take hormone replacement therapy to reduce menopausal symptoms such as hot flashes, night sweats and vaginal dryness. The balance of harms and benefits for that use is expected to be addressed in an imminent report by the federal government's Office of Health Quality Research.

The latest recommendation, published Monday in the Annals of Internal Medicine, comes from an organization accustomed to kicking up controversy. In recent months, the task force has recommended against routine breast cancer screenings for most women younger than 50. It has also urged that the prostate-specific antigen (or PSA) test that has become a standard part of older men's yearly physicals be abandoned.

Read more...

Save to Library

Japan's Radiation Found in California Bluefin Tuna

For the first time, scientists have detected radioactivity in fish that have migrated into California waters from the ocean off Japan, where radiation contaminated the sea after explosions tore through the Fukushima nuclear reactors last year.

Radioactive cesium was detected in samples of highly prized Pacific bluefin tuna, but it is well below levels considered unsafe for humans, the scientists say.

The evidence is "unequivocal" that the tuna--caught off San Diego a year ago--were contaminated with radiation from Japan's nuclear disaster, the researchers said.

Virtually all bluefin tuna on the market in the United States is either farmed or caught far from the Fukushima area, so American consumers should not be affected by radiation contamination in their fish, seafood distributors say. The migratory bluefin studied by the researchers were all caught by sport fishermen and were not headed for the market.

Read more...

Save to Library

Migration of Monsoons Created, Then Killed Harappan Civilization

from the Los Angeles Times (Registration Required)

The slow eastward migration of monsoons across the Asian continent initially supported the formation of the Harappan civilization in the Indus valley by allowing production of large agricultural surpluses, then decimated the civilization as water supplies for farming dried up, researchers reported Monday. The results provide the first good explanation for why the Indus valley flourished for two millennia, sprouting large cities and an empire the size of contemporary Egypt and Mesopotamia combined, then dwindled away to small villages and isolated farms.

The Harappan civilization, named after its largest city, Harappa along the upper Indus River, evolved beginning about 5,200 years ago and reached its height between 4,500 and 3,900 years ago, stretching across what is now Pakistan, northwest India and Eastern Afghanistan. An urban society with large cities, a distinctive style of writing and extensive trade that reached as far as Mesopotamia, the society accounted for about 10% of the Earth's population at its height and rivaled Egypt in its power. Unlike Egypt and Mesopotamia, however, the Harappans did not attempt to develop irrigation to support agriculture. Instead, they relied on the annual monsoons, which allowed the accumulation of large agricultural surpluses--which, in turn, allowed the creation of cities. The civilization was largely forgotten by history until the 1920s, when researchers finally began studying it in depth.

The new research was performed by a team led by geologist Liviu Giosan of the Woods Hole Oceanographic Institution in Woods Hole, Mass., and published in the Proceedings of the National Academy of Science. Working in Pakistan, they used photographs taken by shuttle astronauts and images from the Shuttle Radar Topography Mission to prepare maps of land forms in the region, then verified them on the ground using drilling, coring and manually dug trenches.

Read more...

Save to Library

Study Traces Origins of Monogamous Coupling

from the Los Angeles Times (Registration Required)

The roots of the modern family--monogamous coupling--lie somewhere in our distant evolutionary past, but scientists disagree on how it first evolved. A new study says we should thank two key players: weak males with inferior fighting chops and the females who opted to be faithful to them.

These mating strategies may "have triggered a key step in the very long process of the evolution of the family," said study author Sergey Gavrilets, a biomathematician at the University of Tennessee in Knoxville. "Without it, we wouldn't have the modern family."

The mating structure of humans is strikingly different than that of sexually promiscuous chimps, in which a few alpha males dominate other males in the group and, by dint of their superior fighting prowess, freely mate with the females. Lower-status males are largely shut out from mating opportunities.

Read more...

Save to Library

'What Is' Meets 'What if': The Role of Speculation in Science

from the New York Times (Registration Required)

Woody Allen once said that when you do comedy, you sit at the children's table. The same might be said of speculation in science. And yet speculation is an essential part of science. So how does it fit in? Two recent publications about the misty depths of canine and human history suggest some answers. In one, an international team of scientists concludes that we really don't know when and where dogs were domesticated. Greger Larson of the University of Durham, in England, the first of 20 authors of that report, said of dog DNA, "It's a mess."

In the other, Pat Shipman, an independent scientist and writer, suggests that dogs may have helped modern humans push the Neanderthals out of existence and might even have helped shape human evolution.

Is one right and the other wrong? Are both efforts science--one a data-heavy reality check and the other freewheeling speculation? The research reported by Dr. Larson and his colleagues in the Proceedings of the National Academy of Sciences is solid science--easily judged by peers, at any rate. The essay by Dr. Shipman is not meant to come to any conclusion but to prompt thought and more research. It, too, will be judged by other scientists, and read by many nonscientists.

Read more...

Save to Library

The Enigma 1,800 Miles Below Us

from the New York Times (Registration Required)

Geologists have long known that Earth's core, some 1,800 miles beneath our feet, is a dense, chemically doped ball of iron roughly the size of Mars and every bit as alien. It's a place where pressures bear down with the weight of 3.5 million atmospheres, like 3.5 million skies falling at once on your head, and where temperatures reach 10,000 degrees Fahrenheit -- as hot as the surface of the Sun. It's a place where the term "ironclad agreement" has no meaning, since iron can't even agree with itself on what form to take. It's a fluid, it's a solid, it's twisting and spiraling like liquid confetti.

Researchers have also known that Earth's inner Martian makes its outer portions look and feel like home. The core's heat helps animate the giant jigsaw puzzle of tectonic plates floating far above it, to build up mountains and gouge out seabeds. At the same time, the jostling of core iron generates Earth's magnetic field, which blocks dangerous cosmic radiation, guides terrestrial wanderers and brightens northern skies with scarves of auroral lights.

Now it turns out that existing models of the core, for all their drama, may not be dramatic enough. Reporting recently in the journal Nature, Dario Alfè of University College London and his colleagues presented evidence that iron in the outer layers of the core is frittering away heat through the wasteful process called conduction at two to three times the rate of previous estimates.

Read more...

Save to Library

New and Frozen Frontier Awaits Offshore Oil Drilling

from the New York Times (Registration Required)

WASHINGTON -- Shortly before Thanksgiving in 2010, the leaders of the commission President Obama had appointed to investigate the Deepwater Horizon oil spill in the Gulf of Mexico sat down in the Oval Office to brief him. After listening to their findings about the BP accident and the safety of deepwater drilling, the president abruptly changed the subject. "Where are you coming out on the offshore Arctic?" he asked.

William K. Reilly, a former chief of the Environmental Protection Agency and a commission co-chairman, was startled, as was Carol M. Browner, the president's top adviser at the time on energy and climate change.

Although a proposal by Shell to drill in the Arctic had been a source of dissension, it was not a major focus of the panel's work. "It's not deep water, right?" the president said, noting that Shell's proposal involved low-pressure wells in 150 feet of water, nothing like BP's 5,000-foot high-pressure well that blew out in the gulf.

Read more...

Save to Library

L.A. OKs Ban on Plastic Bags at Checkout

from the Los Angeles Times (Registration Required)

Los Angeles became the largest city in the nation to approve a ban on plastic bags at supermarket checkout lines, handing a hard-fought victory to environmentalists and promising to change the way Angelenos do their grocery shopping.

The City Council voted 13 to 1 to phase out plastic bags over the next 16 months at an estimated 7,500 stores, meaning shoppers will need to bring reusable bags or purchase paper bags for 10 cents each.

The ban came after years of campaigning by clean-water advocates who said it would reduce the amount of trash in landfills, the region's waterways and the ocean. They estimate Californians use 12 billion plastic bags a year and that less than 5% of the state's plastic bags are recycled.

Read more...

Save to Library

Dam's Flow Limit Loosened to Feed Grand Canyon

from the New York Times (Registration Required)

The Interior Department announced a plan on Wednesday to allow periodic increases in the flow of Colorado River water through the Grand Canyon, alleviating the environmental disruption caused by the construction of the Glen Canyon Dam in Arizona in the 1960s.

The secretary of the interior, Ken Salazar, said the plan would allow the river's managers to release excess water--more than twice as much as average flows--through and over the hydroelectric dam at will to help propel silt and sediment downstream into the canyon. By mimicking the river's original dynamics, Interior Department officials said, the flows could help restore the backwater ecosystems in which native fish are most at home.

The goal is partly to enhance sandbars that create backwaters for an endangered fish, the humpback chub. The excess sand also nourishes beaches used by wildlife, hikers and rafters. Environmental groups like the Grand Canyon Trust strongly support the high-flow releases, which have been carried out experimentally three times before, most recently in 2008.

Read more...

Save to Library

Mysterious Sensory Organ Found in Whale's Chin

from NPR

If you came face to face with a great whale, you might find a few surprises in its chin: Like whiskers, if you look closely at the surface. And, hidden inside the chin, lies a mysterious sensory organ, unknown to centuries of whalers and biologists.

You just need the right tools to find it: a high-tech, oversized x-ray machine, and the right saws to slice it into thin pieces that fit in a microscope.

A group of scientists based at the University of British Columbia, in Vancouver, BC, have done all that looking--and they discovered an organ that serves a crucial purpose and answers a longstanding mystery. How do great whales, such as humpbacks and blues, drive their jaws so wide open and then snap them shut, while swimming at full speed?

Read more...

Save to Library

Warning Over Deep-Ocean Stowaways

from BBC News Online

Care must be taken not to spread deep-sea creatures around the world during exploration of the remote ocean floor. Scientists using the famous Alvin sub say the vehicle picked up limpets from a depth of almost 3,000m and inadvertently transferred them alive to another location more than 600km away.

It is surprising because the animals had to cope with huge pressure changes as Alvin conducted its dives. The researchers report the event in the journal Conservation Biology.

Spreading organisms artificially beyond their range in this way could have damaging effects on marine ecosystems, they warn, either by introducing competitors or even disease. The team urges other deep-sea explorers to exercise extreme caution, and to assume hardy stowaways could be hanging on to their vehicles.

Read more...

Save to Library

Stem Cells Take Root in Drug Development

from Nature News

Stem cells have assumed near-mythical status in the popular imagination as a possible cure for every disease under the sun. But while public attention has focused on their potential in regenerative medicine, stem cells have quietly gained a foothold in drug development--a move that may hail a huge but unheralded shake-up of the biological sciences.

"I think there are tremendous parallels to the early days of recombinant DNA in this field," says James Thomson, director of regenerative biology at the Morgridge Institute for Research in Madison, Wisconsin, and one of the founders of Cellular Dynamics International, also in Madison. "I don't think people appreciated what a broad-ranging tool recombinant DNA was in the middle '70s." At the same time, he says, they underestimated the difficulty of using it in treatments.

Now stem cells are in a similar situation, he says, and although therapeutic use is likely to come to fruition eventually, "people underappreciate how broadly enabling a research tool it is", he says.

Read more...

Save to Library

Solid Advance for Cheap Solar Cells

from ScienceNOW Daily News

The price of solar cells has been gliding downward for decades. Now this trend could get a shove from an improvement to a more than 20-year-old solar technology that captures light with dye molecules, an approach that's never managed to catch on. The advance is "one of the most important breakthroughs in dye cells in the last several years," says Thomas Mallouk, a chemist at Pennsylvania State University, University Park, who was not involved in the study.

Eighty percent of the market for solar cells is taken up by cells made from crystalline silicon wafers, which convert about 20% of the energy in incoming sunlight into electricity. Most of the rest of the market consists of "thin film" cells made from different semiconducting alloys that can be cheaper to produce but require toxic or rare elements.

A third class of solar cells, first developed in 1991 by researchers in Switzerland, are the cheapest to make and are more than 12% efficient. These cells, known as dye-sensitized solar cells (DSSCs), consist of millions of tightly packed titanium dioxide nanoparticles, each coated by a single layer of dye molecules. The titanium dioxide-dye combo is then bathed in an electrically conductive liquid containing mobile ions called an electrolyte.

Read more...

Save to Library

Long-Acting Contraceptives Best by Far

from Science News

Long-acting birth control devices are nearly 22 times as reliable as contraceptive pills or other short-acting approaches that need close monitoring, a new study shows. Since about half of all unplanned pregnancies are traceable to failed birth control, switching to a long-term, reversible contraceptive could prevent many accidental pregnancies, researchers say.

"As a doctor, if you had a drug for cancer or hypertension that was 20-fold better than the next drug, you would never write [a prescription] for that other drug," says study coauthor Jeffrey Peipert, a physician and epidemiologist at Washington University in St. Louis. "We hope that clinicians will re-think what is standard practice--that a young woman comes in and gets pills or condom counseling. We have methods that are much, much better."

The findings also hint that if cost were not an issue, most women given a choice of common hormone-based contraceptives would prefer the long-acting devices. About 77 percent of the women who volunteered for the new study chose an intrauterine device (IUD) or a small implant placed under the skin while only 20 percent requested shorter-acting options such as the pill, a vaginal ring or a skin patch. Fewer still opted for hormone injections called Depo-Provera. All costs were covered by the study. The findings appear in the May 24 New England Journal of Medicine.

Read more...

Save to Library

Could Stem Cells Cure MS?

from the Scientist

Human mesenchymal stem cells (hMSCs) have become a popular potential therapy for numerous autoimmune and neurological disorders. But while these bone marrow-derived stem cells have been studied in great detail in the dish, scientists know little about how they modulate the immune system and promote tissue repair in living organisms.

Now, one research team has uncovered a molecular mechanism by which hMSCs promote recovery in a mouse model of multiple sclerosis (MS).

According to research, published online Sunday (May 20) in Nature Neuroscience, a growth factor produced by hMSCs fights MS in two ways: blocking a destructive autoimmune response and repairing neuronal damage. The finding could help advance ongoing clinical trials testing hMSCs as a therapy for MS.

Read more...

Save to Library

Butterfly Species Expands Range with Climate Change

from the New York Times (Registration Required)

A butterfly species in England is expanding its range, thanks to climate change. In the current issue of Science, researchers at the University of York report that the brown argus butterfly has spread its reach in England northward by about 50 miles over 20 years as a warmer climate allow its caterpillars to feed off wild geranium plants, which are widespread in the countryside.

"There was something unusual about the degree to which it was spreading its range," said an author of the study, Jane K. Hill, a biologist at York. "It was turning up in places that were unexpected."

The challenge was figuring out whether or not the butterflies were truly responding to climate change or shifting their range for some other reason. The researchers looked at data on butterfly locations and populations gathered by thousands of volunteers over four decades.

Read more...

Save to Library

New Desalination Technique Yields More Drinkable Water

from Nature News

More than a third of the world already suffers from shortages of potable water--with a rise to 50 percent expected by 2025. Desalination of seawater can help coastal communities address local shortfalls, although the process is costly, and releasing leftover brine back to the ocean has environmental implications. Now a new system promises to produce more drinkable water with less salty effluent.

Kamalesh Sirkar, a New Jersey Institute of Technology (N.J.I.T.) distinguished professor of chemical engineering, says he has devised a direct-contact membrane distillation (DCMD) system that can efficiently wring drinking water out of up to 20 percent-salt-concentrated brine. (After about 25 percent, salt precipitates out of the solution in the membrane distillation system and could damage the membranes, pumps, lines and other components, Sirkar says.)

Normal seawater has a salt concentration of about 3.5 percent, which means the new system can reprocess the same seawater several times. "More water can be recovered with less residue," Sirkar says.

Read more...

Save to Library

Fish Forensics Gets an Upgrade

from ScienceNOW Daily News

It's no wonder that fish stocks around the world are plummeting. Up to 25% of the global catch comes from illegal, unreported, and unregulated fishing. Now, science has stepped in to offer a new method to identify contraband fish. A €4 million pan-European project, launched in 2008 and called FishPopTrace, has devised a much-anticipated way to differentiate marine populations of the same species with up to 100% accuracy.

Regulatory agencies like those in the European Union are trying to crack down on the illegal fish trade, but the task is not easy. How does a manager tell the difference between, for example, an illegally harvested Northeast Arctic cod and a perfectly legal Eastern Baltic cod? They belong to the same species but come from very different populations.

The new approach relies on genetic variants called single-nucleotide polymorphisms. SNPs occur when tiny segments of DNA differ between populations. For example, the Northeast Arctic cod may have a C nucleotide in the middle of a gene, whereas the Eastern Baltic cod may instead have a T in the same position.

Read more...

Save to Library



 

Connect With Us:

    Pinterest Icon Google+ Icon Twitter Icon Facebook Icon Sm


Subscribe to Our Content!

Visit our RSS Feeds page to choose among 13 customized feeds, or create a free My AmSci account to request an email notice whenever a specified author, department or discipline appears online.


Subscribe to Free eNewsletters!

  • Sigma Xi SmartBrief:

    A free daily summary of the latest news in scientific research. Each story is summarized concisely and linked directly to the original source for further reading.

  • American Scientist Update

  • An early peek at each new issue, with descriptions of feature articles, columns, Science Observers and more. Every other issue contains links to everything in the latest issue's table of contents.

  • Scientists' Nightstand

  • News of book reviews published in American Scientist and around the web, as well as other noteworthy happenings in the world of science books.

    To sign up for automatic emails of the American Scientist Update and Scientists' Nightstand issues, create an online profile, then sign up in the My AmSci area.


Subscribe to American Scientist