الثلاثاء، 30 يوليو 2013

ScienceDaily: Top News

ScienceDaily: Top News


Math model predicts effects of diet, physical activity on childhood weight

Posted: 29 Jul 2013 08:30 PM PDT

Researchers have created and confirmed the accuracy of a mathematical model that predicts how weight and body fat in children respond to adjustments in diet and physical activity.

Decision aids reduce men's conflict about PSA screening, but don't change their decisions

Posted: 29 Jul 2013 08:18 PM PDT

Men who decide to be screened for prostate cancer and those who forgo PSA screening stick with their decisions after receiving materials explaining the risks and benefits of the test. The decision aids greatly increased their knowledge about screening and reduced their conflict about what to do, but did not have an impact on their screening decision when measured a year later.

Breastfeeding duration appears associated with intelligence later in life

Posted: 29 Jul 2013 08:16 PM PDT

Breastfeeding longer is associated with better receptive language at 3 years of age and verbal and nonverbal intelligence at age 7 years, according to a new study.

Worsening trends in back pain management

Posted: 29 Jul 2013 08:15 PM PDT

Patient care could be enhanced and the health care system could see significant cost savings if health care professionals followed published clinical guidelines to manage and treat back pain.

Capturing black hole spin could further understanding of galaxy growth

Posted: 29 Jul 2013 08:14 PM PDT

Astronomers have found a new way of measuring the spin in supermassive black holes, which could lead to better understanding about how they drive the growth of galaxies.

Two 6,000-year-old 'halls of the dead' unearthed

Posted: 29 Jul 2013 08:14 PM PDT

The remains of two large 6000-year-old halls, each buried within a prehistoric burial mound, have been discovered by archaeologists. The sensational finds on Dorstone Hill, near Peterchurch in Herefordshire, were thought to be constructed between 4000 and 3600 BC.

Monogamy evolved as a mating strategy: New research indicates that social monogamy evolved as a result of competition

Posted: 29 Jul 2013 02:22 PM PDT

Social monogamy, where one breeding female and one breeding male are closely associated with each other over several breeding seasons, appears to have evolved as a mating strategy, new research reveals. It was previously suspected that social monogamy resulted from a need for extra parental care by the father.

Human cells respond in healthy, unhealthy ways to different kinds of happiness

Posted: 29 Jul 2013 01:19 PM PDT

Human bodies recognize at the molecular level that not all happiness is created equal, responding in ways that can help or hinder physical health, according to new research.

Hot flashes? Thank evolution

Posted: 29 Jul 2013 01:19 PM PDT

A study of mortality and fertility patterns among seven species of wild apes and monkeys and their relatives, compared with similar data from hunter-gatherer humans, shows that menopause sets humans apart from other primates.

Computer scientists develop 'mathematical jigsaw puzzles' to encrypt software

Posted: 29 Jul 2013 01:19 PM PDT

Computer science experts have designed a system to encrypt software so that it only allows someone to use a program as intended while preventing any deciphering of the code behind it. This is known in computer science as "software obfuscation," and it is the first time it has been accomplished.

Could sleeping stem cells hold key to treatment of aggressive blood cancer?

Posted: 29 Jul 2013 01:19 PM PDT

Scientists studying an aggressive form of leukemia have discovered that rather than displacing healthy stem cells in the bone marrow as previously believed, the cancer is putting them to sleep to prevent them forming new blood cells.

New modular vaccine design combines best of existing vaccine technologies

Posted: 29 Jul 2013 01:18 PM PDT

Researchers have developed a new method of vaccine design -- Multiple Antigen Presentation System. It could speed new vaccine development for range of globally serious pathogens, infectious agents. Method permits rapid construction of new vaccines that bring together benefits of whole-cell and acellular or defined subunit vaccination and activate multiple arms of the immune system simultaneously against one or more pathogens, generating robust immune protection with lower risk of adverse effects.

Social amoebae travel with a posse: Tiny single-celled organisms have amazingly complicated social lives

Posted: 29 Jul 2013 01:17 PM PDT

Some social amoebae farm the bacteria they eat. Now scientists have taken a closer look at one lineage, or clone, of D. discoideum farmer. This farmer carries not one but two strains of bacteria. One strain is the "seed corn" for a crop of edible bacteria, and the other strain is a weapon that produces defensive chemicals. The edible bacteria, the scientists found, evolved from the toxic one.

Therapy may curb kidney deterioration in patients with rare disorder

Posted: 29 Jul 2013 01:17 PM PDT

Researchers have overcome a biological hurdle to find improved treatments for patients with methylmalonic acidemia. Using genetically engineered mice created for their studies, the team identified a set of biomarkers of kidney damage -- a hallmark of the disorder -- and demonstrated that antioxidant therapy protected kidney function in the mice.

Aberrant splicing saps the strength of 'slow' muscle fibers

Posted: 29 Jul 2013 01:17 PM PDT

In people with myotonic dystrophy, the second most common form of muscular dystrophy, type 1 fibers do not work well, wasting away as the genetic disorder takes over. Researchers have shown how an aberrant alternative splicing program changes the form of an enzyme involved in the fundamental metabolism of these muscle cells, leaving them unable to sustain exercise.

How does hydrogen metallize?

Posted: 29 Jul 2013 01:17 PM PDT

Hydrogen is deceptively simple. It has only a single electron per atom, but it powers the sun and forms the majority of the observed universe. As such, it is naturally exposed to the entire range of pressures and temperatures available in the whole cosmos. But researchers still struggle to understand even basic aspects of its various forms under high-pressure conditions. New work makes significant additions to our understanding of this vital element's high-pressure behavior.

'Cowcatcher' enzyme fixes single-strand DNA

Posted: 29 Jul 2013 01:17 PM PDT

Single-stranded DNA repair is a critical process whose mechanism has never been determined. Now, researchers have figured out how this process works, focusing on an enzyme associated with the replication complex that detects DNA damage, stops replication and repairs the damage.

Study looks beyond averages to track variability in a bacterial population

Posted: 29 Jul 2013 01:17 PM PDT

As a result of the variable nature of gene expression, genetically identical cells inhabiting the same environment can vary significantly in their numbers of key enzymes, which in turn results in strikingly different cellular behaviors. Researchers have captured some of this variability to identify several behavior sub-types in a bacterial population.

NASA's Chandra sees eclipsing planet in X-rays for first time

Posted: 29 Jul 2013 01:16 PM PDT

For the first time since exoplanets, or planets around stars other than the sun, were discovered almost 20 years ago, X-ray observations have detected an exoplanet passing in front of its parent star. An advantageous alignment of a planet and its parent star in the system HD 189733, which is 63 light-years from Earth, enabled NASA's Chandra X-ray Observatory and the European Space Agency's XMM Newton Observatory to observe a dip in X-ray intensity as the planet transited the star.

Evolution of monogamy in humans the result of infanticide risk, new study suggests

Posted: 29 Jul 2013 01:15 PM PDT

The threat of infants being killed by unrelated males is the key driver of monogamy in humans and other primates, a new study suggests.

Evolution of diverse sex-determining mechanisms in mammals

Posted: 29 Jul 2013 01:15 PM PDT

Researchers have found that a genetic process among the many species of rodents could have significant implications regarding our assumptions about sex determination and the pace of evolution.

Pulsating star sheds light on exoplanet

Posted: 29 Jul 2013 01:15 PM PDT

Astronomers have devised a way to measure the internal properties of stars —- a method that offers more accurate assessments of their orbiting planets.

Essential clue to Huntington's disease solution found

Posted: 29 Jul 2013 01:15 PM PDT

Researchers have discovered a solution to a long-standing medical mystery in Huntington's disease (HD).

Natural affinities -- unrecognized until now -- may have set stage for life to ignite

Posted: 29 Jul 2013 01:15 PM PDT

The chemical components crucial to the start of life on Earth may have primed and protected each other in never-before-realized ways, according to new research. It could mean a simpler scenario for how that first spark of life came about on the planet.

Mini-monsters of the forest floor

Posted: 29 Jul 2013 01:15 PM PDT

A biologist has identified 33 new species of predatory ants in Central America and the Caribbean, and named about a third of the tiny but monstrous-looking insects after ancient Mayan lords and demons.

Hope for tigers lives in Sumatra

Posted: 29 Jul 2013 11:47 AM PDT

Recent findings from a camera trap survey in Sumatra, Indonesia, have uncovered a burgeoning tiger stronghold on an island that typically makes headlines for its rampant loss of forests and wildlife.

Make it yourself with a 3-D printer and save big time

Posted: 29 Jul 2013 11:46 AM PDT

A new study shows that families can save hundreds if not thousands of dollars by making their own household items with a 3-D printer.

Pushing microscopy beyond standard limits

Posted: 29 Jul 2013 10:36 AM PDT

Engineers have devised a method to convert a relatively inexpensive conventional microscope into a billion-pixel imaging system that significantly outperforms the best available standard microscope. Such a system could greatly improve the efficiency of digital pathology, in which specialists need to review large numbers of tissue samples. By making it possible to produce robust microscopes at low cost, the approach also has the potential to bring high-performance microscopy capabilities to medical clinics in developing countries.

See-through solar film: Researchers double efficiency of novel solar cell

Posted: 29 Jul 2013 10:36 AM PDT

Nearly doubling the efficiency of a photovoltaic breakthrough made in 2012, researchers have developed a two-layer, see-through solar film that could be placed on building windows, sunroofs, smartphone displays and other surfaces to harvest energy from the sun.

Plant-based compound may inhibit HIV

Posted: 29 Jul 2013 10:36 AM PDT

A compound found in soybeans may become an effective HIV treatment without the drug resistance issues faced by current therapies.

Tetrapod nanocrystals light the way to stronger polymers

Posted: 29 Jul 2013 10:36 AM PDT

Researchers have developed advanced opto-mechanical stress probes based on tetrapod quantum dots (tQDs) that allow precise measurement of the tensile strength of polymer fibers with minimal impact on the polymer's mechanical properties. These fluorescent tQDs could lead to stronger, self-repairing polymer nanocomposites.

Like water for batteries: Water 'likeability' plays role in battery-charged objects

Posted: 29 Jul 2013 10:35 AM PDT

Objects made from graphite -- such as lithium-ion batteries -- are "hydrophobic," meaning that they "dislike" water. For decades this lack of likeability has presented significant challenges in terms of building more durable technological devices made with graphite -- until now.

Ice-free Arctic winters could explain amplified warming during Pliocene

Posted: 29 Jul 2013 10:35 AM PDT

Year-round ice-free conditions across the surface of the Arctic Ocean could explain why the Earth was substantially warmer during the Pliocene Epoch than it is today, despite similar concentrations of carbon dioxide in the atmosphere, according to new research.

Heavy cell phone use linked to oxidative stress

Posted: 29 Jul 2013 10:35 AM PDT

A new study finds a strong link between heavy cell phone users and higher oxidative stress to all aspects of a human cell, including DNA. Uniquely based on examinations of the saliva of cell phone users, the research provides evidence of a connection between cell phone use and cancer risk.

Diets lacking omega-3s lead to anxiety, hyperactivity in teens: Generational omega-3 deficiencies have worsening effects over time

Posted: 29 Jul 2013 10:35 AM PDT

Diets lacking omega-3 fatty acids -- found in foods like wild fish, some eggs, and grass-fed livestock -- can have worsened effects over consecutive generations, especially affecting teens, according to a new study.

Premature aging of immune cells in joints of kids with chronic arthritis

Posted: 29 Jul 2013 10:35 AM PDT

The joints of children with the most common form of chronic inflammatory arthritis contain immune cells that resemble those of 90-year-olds, according to a new study. The findings suggest that innovative treatment approaches could aim to prevent premature aging of immune cells.

PTSD after traumatic events: Which teens are at risk?

Posted: 29 Jul 2013 10:35 AM PDT

Researchers have identified risk factors for children exposed to trauma in developing PTSD from analyzing 6,483 teen–parent pairs from the National Comorbidity Survey Replication, a survey of the prevalence and correlates of mental disorders in the United States. 61 percent of the teens (ages 13 to 17) had been exposed to at least one potentially traumatic event in their lifetime. Nineteen percent had experienced three or more such events.

Large Gulf dead zone, but smaller than predicted

Posted: 29 Jul 2013 10:34 AM PDT

Scientists have found a large Gulf of Mexico oxygen-free or hypoxic 'dead' zone, but not as large as had been predicted. Measuring 5,840 square miles, an area the size of Connecticut, the 2013 Gulf dead zone indicates nutrients from the Mississippi River watershed, which drains 40 percent of the lower 48 states, are continuing to affect the nation's commercial and recreational marine resources in the Gulf.

Antibiotic reduction campaigns do not necessarily reduce resistance

Posted: 29 Jul 2013 10:34 AM PDT

Antibiotic use -- and misuse -- is the main driver for selection of antibiotic resistant bacteria. This has led many countries to implement interventions designed to reduce overall antibiotic consumption. Now, using methicillin resistant Staphylococcus aureus as an example, scientists warn that simply reducing antibiotics consumption does not necessarily reduce resistance.

Novel material for cooling of electronic devices discovered

Posted: 29 Jul 2013 10:31 AM PDT

As microelectronic devices become smaller, faster and more powerful, thermal management becomes a critical challenge. This research provides new insight into the nature of thermal transport at a quantitative level.

Global warming endangers South American water supply

Posted: 29 Jul 2013 10:31 AM PDT

Chile and Argentina may face critical water storage issues due to rain-bearing westerly winds over South America's Patagonian Ice-Field to moving south as a result of global warming.

Early exposure to insecticides gives amphibians higher tolerance later

Posted: 29 Jul 2013 10:31 AM PDT

Amphibians exposed to insecticides early in life -- even those not yet hatched -- have a higher tolerance to those same insecticides later in life, according to a recent study.

Of bears and berries: Return of wolves aids grizzly bears in Yellowstone

Posted: 29 Jul 2013 10:31 AM PDT

A new study suggests that the return of wolves to Yellowstone National Park is beginning to bring back a key part of the diet of grizzly bears that has been missing for much of the past century -- berries that help bears put on fat before going into hibernation. The berries could aid bear survival and reproduction.

Cells move as concentration shifts

Posted: 29 Jul 2013 10:30 AM PDT

Sheets of biological cells move along the organs they cover by altering the external concentrations of specific molecules. What do wound healing, cancer metastasis, and bacteria colonies have in common? They all involve the collective displacement of biological cells. New research sheds some new light on the physical mechanisms provoking the displacement of a sheet of cell, known as an epithelium. It typically covers our organs including the stomach and intestine, as well as our epidermis. In a new article scientists explain the importance of understanding the displacement of the epithelium as a means of influencing the biological process involved in healing.

X chromosomes: Undoing a hairpin doubles gene activity

Posted: 29 Jul 2013 10:30 AM PDT

Male fruit flies have one X chromosome per cell, females have two. So genes on the male X must work twice as hard to produce the same amount of protein as its female counterparts. Scientists have found a new switch involved in making this possible.

Therapeutic fecal transplant: Hope for cure of childhood diarrhea comes straight from the gut

Posted: 29 Jul 2013 10:30 AM PDT

Call it therapeutic poop, if you will, but the best hope yet for an effective treatment of childhood infections with the drug-resistant bacterium C. difficile may come straight from the gut, according to recent research. This is why pediatric gastroenterologists are launching a fecal transplantation program for patients with recurrent diarrhea caused by what they say is a wily pathogen that is increasingly impervious to drugs and a rapidly growing problem among children and adults.

Statins suppress Rett syndrome symptoms in mice

Posted: 29 Jul 2013 08:20 AM PDT

Statins, a class of cholesterol-lowering drugs found in millions of medicine cabinets, may help treat Rett Syndrome, according to a new study.

When fluid dynamics mimic quantum mechanics

Posted: 29 Jul 2013 08:19 AM PDT

Researchers expand the range of quantum behaviors that can be replicated in fluidic systems, offering a new perspective on wave-particle duality.

Cockatoos know what's going on behind barriers

Posted: 29 Jul 2013 08:19 AM PDT

How do you know that the cookies are still there even though they have been placed in a cookie jar out-of-sight? Scientists show that "object permanence" abilities in a cockatoo rivals that of apes and four-year-old humans.

Best of both worlds: Solar hydrogen production breakthrough

Posted: 29 Jul 2013 08:19 AM PDT

Using a simple solar cell and a photo anode made of a metal oxide, scientists have successfully stored nearly five percent of solar energy chemically in the form of hydrogen. This is a major feat as the design of the solar cell is much simpler than that of the high-efficiency triple-junction cells based on amorphous silicon or expensive III-V semiconductors that are traditionally used for this purpose.

Experimental quest to test Einstein's speed limit

Posted: 29 Jul 2013 08:19 AM PDT

Special relativity states that the speed of light is the same in all frames of reference and that nothing can exceed that limit. UC Berkeley physicists used a novel experimental system -- the unusual electron orbitals of dysprosium -- to test whether the maximum speed of electrons follows this rule. The answer is yes, to tighter limits than ever before. They plan another experiment a thousand times more sensitive, approaching the realm where theory may break down.

Impaired visual signals might contribute to schizophrenia symptoms

Posted: 29 Jul 2013 05:33 AM PDT

By observing the eye movements of schizophrenia patients while playing a simple video game, a researcher has discovered a potential explanation for some of their symptoms, including difficulty with everyday tasks.

Intent to harm: Willful acts seem more damaging

Posted: 29 Jul 2013 05:33 AM PDT

How harmful we perceive an act to be depends on whether we see the act as intentional, reveals new research.

Living longer, living healthier: People are remaining healthier later in life

Posted: 29 Jul 2013 05:33 AM PDT

Based on data collected between 1991 and 2009 from almost 90,000 individuals who responded to the Medicare Current Beneficiary Survey, scientists say that, even as life expectancy has increased over the past two decades, people have become increasingly healthier later in life.

Higher cancer incidences found in regions near refineries and plants that release benzene

Posted: 29 Jul 2013 05:33 AM PDT

The incidence of a particular type of blood cancer is significantly higher in regions near facilities that release the chemical benzene into the environment.

Borneo's orangutans are coming down from the trees; Behavior may show adaptation to habitat change

Posted: 29 Jul 2013 05:33 AM PDT

Orangutans might be the king of the swingers, but primatologists in Borneo have found that the great apes spend a surprising amount of time walking on the ground. The research found that it is common for orangutans to come down from the trees to forage or to travel, a discovery which may have implications for conservation efforts.

New whipray species identified by its DNA

Posted: 29 Jul 2013 05:32 AM PDT

Biologists have analysed tissue samples of 115 spotted whiprays of the Himantura genus, collected in various parts of the Indio-Pacific region. By means of genetic markers -- as opposed to morphological criteria only -- the scientists were able to describe these leopard-skin whiprays in detail and demonstrate that they are isolated from each other in terms of reproduction. They have also discovered a new species that they call Himantura tutul, which belongs to a genetic line that is totally distinct from the three other species that are known in the same group: H. leoparda, H. uarnak and H. undulata. They frequent the same costal habitats but occupy different ecological niches.

Tuna and floating objects: Mysterious links

Posted: 29 Jul 2013 05:32 AM PDT

More than 2 000 years ago, Roman fishermen already used the natural propensity of some species of fish to gather under floating objects, to enhance their catches in the Mediterranean. Today, numerous industrial and artisanal tuna fisheries around the world exploit this "aggregating phenomenon." Over the last thirty years, seine fishing in particular has developed rapidly through the use of massive floating objects, natural at first, then more recently fish aggregation devices (abbreviated to FAD) remotely monitored using electronic beacons. Today, these floating objects enable 40% of worldwide tropical tuna catches.

Cement converted into an electrical conductor

Posted: 29 Jul 2013 05:32 AM PDT

Researchers have developed a cementitious material incorporating carbon nanofibers in its composition, turning cement into an excellent conductor of electricity capable of performing functions beyond its usual structural function.

Young cannabis-smokers aware of the health risks

Posted: 29 Jul 2013 05:32 AM PDT

91 percent of on average 20-year-old Swiss men drink alcohol, almost half of whom drink six beverages or more in a row and are thus at-risk consumers. 44 percent of Swiss men smoke tobacco, the majority of whom are at-risk consumers – they smoke at least once a day. 36 percent of young adults smoke cannabis, whereby over half are at-risk consumers, using the drug at least twice a week. Researchers investigated whether these young Swiss men read up on addictive substances such as alcohol, tobacco, cannabis or other drugs and are aware and understand the risks of their consumption by conducting a survey of 12,000 men under a national cohort study as they were recruited for national service. 

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