Παρασκευή 28 Φεβρουαρίου 2014

ScienceDaily: Top News

ScienceDaily: Top News


Link found between pollutants, certain complications of obesity

Posted: 27 Feb 2014 09:55 AM PST

A link has been found between a type of pollutant and certain metabolic complications of obesity. The breakthrough could eventually help improve the prevention, diagnosis, and treatment of cardiometabolic risk associated with obesity, such as diabetes, hypertension and cardiovascular disease. Persistent organic pollutants (POPs) are human-made chemicals used in agricultural, industrial and manufacturing processes. Due to their toxicity, POPs have been strictly and internationally regulated to ensure public health. However, because they have the ability to resist environmental degradation, POPs can still be found all around the world, even in areas where they have never been used, and remain omnipresent in our environment and food products. Thus, virtually all humans are exposed to POPs daily. In this new research, POPs have been found to accelerate the development of prediabetes and obesity in mice, thereby mimicking the unfavourable cardiometabolic profile characteristic of certain obese individuals.

Faster anthrax detection could speed bioterror response

Posted: 27 Feb 2014 09:55 AM PST

Shortly following the 9/11 terror attack in 2001, letters containing anthrax spores were mailed around the country killing five people and infecting 17 others. At the time, no testing system was in place to screen the letters. Currently, first responders have tests that can provide results in about 24-48 hours. Now, researchers have tested a new method for anthrax detection that can identify anthrax in only a few hours.

'Oddball science' has proven worth, biologists say

Posted: 27 Feb 2014 09:55 AM PST

Scoffing at or cutting funds for basic biological research on unusual animal adaptations from Gila monster venom to snail sex, though politically appealing to some, is short-sighted and only makes it more likely that important economic and social benefits will be missed in the long run, say a group of evolutionary biologists.

Ancient 'great leap forward' for life in the open ocean: Cyanobacteria sheds light on how complex life evolved on earth

Posted: 27 Feb 2014 09:55 AM PST

Plankton in the Earth's oceans received a huge boost when microorganisms capable of creating soluble nitrogen 'fertilizer' directly from the atmosphere diversified and spread throughout the open ocean. This event occurred at around 800 million years ago and it changed forever how carbon was cycled in the ocean.

Study uncovers why autism is more common in males

Posted: 27 Feb 2014 09:52 AM PST

Males are at greater risk for neurodevelopmental disorders, such as autism spectrum disorder, than females, but the underlying reasons have been unclear. A large cohort study provides compelling evidence in support of the 'female protective model,' which proposes that females require more extreme genetic mutations than do males to push them over the diagnostic threshold for neurodevelopmental disorders. Researchers found that females diagnosed with a neurodevelopmental disorder or ASD had a greater number of harmful CNVs than did males diagnosed with the same disorder. Moreover, females diagnosed with ASD had a greater number of harmful SNVs than did males with ASD. These findings suggest that the female brain requires more extreme genetic alterations than does the male brain to produce symptoms of ASD or neurodevelopmental disorders.

Battery-free technology brings gesture recognition to all devices

Posted: 27 Feb 2014 09:52 AM PST

Computer scientists have built a low-cost gesture recognition system that runs without batteries and lets users control their electronic devices hidden from sight with simple hand movements. The prototype, called "AllSee," uses existing TV signals as both a power source and the means for detecting a user's gesture command.

NASA's Curiosity Mars Rover views striated ground

Posted: 27 Feb 2014 09:10 AM PST

NASA's Curiosity Mars rover has reached an area where orbital images had piqued researchers' interest in patches of ground with striations all oriented in a similar direction.

Radar images of near-Earth Asteroid 2006 DP14

Posted: 27 Feb 2014 09:08 AM PST

A collage of radar images of near-Earth asteroid 2006 DP14 was generated by NASA scientists using the 230-foot (70-meter) Deep Space Network antenna at Goldstone, Calif., on the night of Feb. 11, 2014.

Big thaw projected for Antarctic sea ice: Ross Sea will reverse current trend, be largely ice free in summer by 2100

Posted: 27 Feb 2014 08:55 AM PST

A new modeling study suggests that a recent observed increase in summer sea-ice cover in Antarctica's Ross Sea is likely short-lived, with the area projected to lose more than half its summer sea ice by 2050 and more than three quarters by 2100. These changes will significantly impact marine life in what is one of the world's most productive and unspoiled marine ecosystems.

Researchers X-ray living cancer cells

Posted: 27 Feb 2014 08:55 AM PST

Scientists have carried out the first studies of living biological cells using high-energy X-rays. "The new method for the first time enables us to investigate the internal structures of living cells in their natural environment using hard X-rays,' emphasizes the leader of the working group. "Thanks to the ever-greater resolution of the various investigative techniques, it is increasingly important to know whether the internal structure of the sample changes during sample preparation." In future, the new technique will make it possible to study unchanged living cells at high resolution.

Type 1 diabetes: Vitamin D deficiency occurs in early stage

Posted: 27 Feb 2014 08:54 AM PST

Low levels of vitamin D are commonly found in people with type 1 diabetes. But even children who have multiple positive islet autoantibodies without manifest type 1 diabetes have lower levels of vitamin D in their blood. This does not appear, however, to influence the progression of the disease from pre-diabetes to diabetes, according to scientists. "Vitamin D deficiency precedes the onset of type 1 diabetes. This may be a consequence of an immune response," one author says. "In the case of prediabetic children, we must therefore be mindful of the risk of vitamin D deficiency and consider recommending vitamin D supplementation at an early stage of type 1 diabetes."

Low birth weight reduces ability to metabolize drugs throughout life

Posted: 27 Feb 2014 07:11 AM PST

Another concern related to low birth weight has been found by researchers: a difference in how the body reacts to drugs, which may last a person's entire life and further complicate treatment of illnesses or diseases that are managed with medications. The findings add to the list of health problems that are already known to correspond to low birth weight, such as a predisposition for adult-onset diabetes, hypertension, and obesity. The implication, researchers say, is that low birth weight may not only cause increased disease, but it may also lessen the effectiveness of the drugs used to treat those diseases.

The pain of social exclusion: Physical pain brain circuits activated by 'social pain'

Posted: 27 Feb 2014 07:11 AM PST

"Social" pain hurts physically, even when we see it in others. The distress caused by social stimuli (e.g., losing a friend, experiencing an injustice or more in general when a social bond is threatened) activates brain circuits related to physical pain: as observed in a new study. This also applies when we experience this type of pain vicariously as an empathic response (when we see somebody else experiencing it).

Why dark chocolate is good for your heart

Posted: 27 Feb 2014 06:21 AM PST

It might seem too good to be true, but dark chocolate is good for you and scientists now know why. Dark chocolate helps restore flexibility to arteries while also preventing white blood cells from sticking to the walls of blood vessels. Both arterial stiffness and white blood cell adhesion are known factors that play a significant role in atherosclerosis. What's more, the scientists also found that increasing the flavanol content of dark chocolate did not change this effect.

Cushing's syndrome: Genetic basis for cortisol excess

Posted: 27 Feb 2014 06:20 AM PST

Cushing's syndrome has been found to be linked to a genetic basis for cortisol excess. Cortisol is a hormone that is produced by the adrenal gland in response to stressful events, and modulates a whole spectrum of physiological processes. An international research collaboration has now identified genetic mutations that lead to the production and secretion of cortisol in the absence of an underlying stressor. This condition, known as Cushing's syndrome, can be successfully treated by surgical removal of the affected adrenal gland.

Ecological impacts of invasive species can be readily predicted from features of their behavior

Posted: 27 Feb 2014 06:20 AM PST

Ecologists have studied the behavior of some of the "world's worst" invasive species, including the large-mouth bass, an invasive fish which typically devastates invertebrate and other fish communities wherever it is introduced. They have revealed that the ecological impacts of invasive species might be readily predicted from features of their behavior.

Probing the edge of chaos: How do variable physical characteristics behave at the point preceding onset of chaos?

Posted: 27 Feb 2014 06:20 AM PST

The edge of chaos -- right before chaos sets in -- is a unique place. It is found in many dynamical systems that cross the boundary between a well-behaved dynamics and a chaotic one. Now, physicists have shown that the distribution -- or frequency of occurrence -- of the variables constituting the physical characteristics of such systems at the edge of chaos has a very different shape than previously reported distributions. This could help us better understand natural phenomena with a chaotic nature.

Altruistic suicide in organisms helps relatives by providing nutrients to kin

Posted: 27 Feb 2014 06:14 AM PST

The question of why an individual would actively kill itself has been an evolutionary mystery. Death could hardly provide a fitness advantage to the dying individual. However, a new study has found that in single-celled algae, suicide benefits the organism's relatives. Researchers have known that when an organism commits suicide by digesting up its own body, it releases nutrients into the environment that can be used by other organisms. Now they've proven that these nutrients can only be used by relatives. In fact, the nutrients inhibit the growth of non-relatives, so not only does suicide benefit relatives, it can also harm competitors.

Digital ears in the rainforest: Estimating dynamics of animal populations by using sound recordings and computing

Posted: 27 Feb 2014 06:14 AM PST

A Finnish-Brazilian project is constructing a system that could estimate the dynamics of animal populations by using sound recordings, statistics and scientific computing. The canopy in a Brazilian rainforest is bustling with life, but nothing is visible from the ground level. The digital recorders attached to the trees, however, are picking up the noises of birds.

Tooth extraction prior to cardiac surgery may increase risk of adverse outcomes

Posted: 27 Feb 2014 06:12 AM PST

Removing an infected tooth prior to cardiac surgery may increase the risk of major adverse outcomes, including risk of death prior to surgery, even though the practice is relatively routine. This research points to a significant departure from current understanding, guideline and practice, and the authors note that further research is required before recommendations and practice are changed.

Smarter colorectal screening could improve senior health

Posted: 27 Feb 2014 06:12 AM PST

Age-based colorectal cancer screening guidelines could lead to inappropriate use and contribute to healthy seniors missing out on the preventative tests including colonoscopy. Large health system, Medicare and many private insurers use quality measures to encourage screening among 50- to 75-year-olds. An unhealthy, 75-year-old -- whose life expectancy is estimated at less than five years -- was significantly more likely to undergo screening than a 76-year-old who's in good health, the study found. The study suggests the upper age cut-off could unintentionally discourage screening for these healthy, older individuals, leading them to miss out on the colorectal screenings known to prevent cancer.

Secondhand smoke exposure linked to adverse pregnancy outcomes

Posted: 26 Feb 2014 06:12 PM PST

Secondhand smoking is linked with pregnancy loss, including miscarriage, stillbirth and tubal ectopic pregnancy, according to new research. The study findings mark a significant step toward clarifying the risks of secondhand smoke exposure.

Scientists wake up to causes of sleep disruption in Alzheimer's disease

Posted: 26 Feb 2014 06:12 PM PST

New research using fruit flies with Alzheimer's protein finds that the disease doesn't stop the biological clock ticking but detaches it from the sleep-wake cycle that it usually regulates. Findings could lead to more effective ways to improve sleep patterns in those with Alzheimer's.

Over 80s often over-treated for stroke prevention

Posted: 26 Feb 2014 06:12 PM PST

People in their 80s are often prescribed drugs to ward off a stroke when the risk of a stroke is not that high and the drugs have other side effects, suggest a new medical article. Statins and antihypertensive drugs were the most commonly prescribed cardiovascular drugs in the UK in 2006. And they are widely prescribed to patients in their 80s to ward off stroke. This is despite the fact that the research shows that, by this age, high blood pressure is not a key contributory risk factor, and high cholesterol has little effect on stroke risk, overall.

DNA test better than standard screens in identifying fetal chromosome abnormalities

Posted: 26 Feb 2014 02:46 PM PST

A new study potentially has significant implications for prenatal testing for major fetal chromosome abnormalities. The study found that in a head-to-head comparison of noninvasive prenatal testing using cell free DNA (cfDNA) to standard screening methods, cfDNA testing (verifi prenatal test, Illumina, Inc.) significantly reduced the rate of false positive results and had significantly higher positive predictive values for the detection of fetal trisomies 21 and 18.

Water filter from the sapwood in pine tree branches

Posted: 26 Feb 2014 02:45 PM PST

If you've run out of drinking water during a lakeside camping trip, there's a simple solution: Break off a branch from the nearest pine tree, peel away the bark, and slowly pour lake water through the stick. The improvised filter should trap any bacteria, producing fresh, uncontaminated water. In fact, scientists have discovered that this low-tech filtration system can produce up to four liters of drinking water a day -- enough to quench the thirst of a typical person. The researchers demonstrate that a small piece of sapwood can filter out more than 99 percent of the bacteria E. coli from water.

Waterbirds' hunt aided by specialized tail: Swimming birds evolved rudder-like tail to dive for food

Posted: 26 Feb 2014 02:45 PM PST

The convergent evolution of tail shapes in diving birds may be driven by foraging style. Birds use their wings and specialized tail to maneuver through the air while flying. It turns out that the purpose of a bird's tail may have also aided in their diversification by allowing them to use a greater variety of foraging strategies. To better understand the relationship between bird tail shape and foraging strategy, researchers examined the tail skeletal structure of over 50 species of waterbirds, like storks, pelicans, and penguins, and shorebirds, like gulls and puffins. They first categorized each species by foraging strategy, such as aerial, terrestrial, and pursuit diving, and then compared the shape and structure of different tails.

Impact on mummy skull suggests murder

Posted: 26 Feb 2014 02:45 PM PST

Blunt force trauma to the skull of a mummy with signs of Chagas disease may support homicide as cause of death, which is similar to previously described South American mummies. Radiocarbon dated to around 1450 -- 1640 AD, skeletal examination indicated that the mummy was likely 20-25 years old at the time of her death, and her skull exhibits typical Incan-type skull formations.

Cows are smarter when raised in pairs: Evidence practice of housing calves alone linked to learning difficulties

Posted: 26 Feb 2014 02:45 PM PST

Cows learn better when housed together, which may help them adjust faster to complex new feeding and milking technologies on the modern farm, a new study finds. Dairy calves become better at learning when a "buddy system" is in place. The study also provides the first evidence that the standard practice of individually housing calves is associated with certain learning difficulties.

One gene influences recovery from traumatic brain injury

Posted: 26 Feb 2014 02:45 PM PST

One change in the sequence of the BDNF gene causes some people to be more impaired by traumatic brain injury than others with comparable wounds, new research shows. The study measured general intelligence in a group of 156 Vietnam War veterans who suffered penetrating head injuries during the war. All of the study subjects had damage to the prefrontal cortex, a brain region behind the forehead that is important to cognitive tasks such as planning, problem-solving, self-restraint and complex thought. The team found that a single polymorphism (a difference in one "letter" of the sequence) in the BDNF gene accounted for significant differences in intelligence among those with similar injuries and comparable intelligence before being injured.

Our memory for sounds is significantly worse than our memory for visual or tactile things

Posted: 26 Feb 2014 02:44 PM PST

Remember that sound bite you heard on the radio this morning? The grocery items your spouse asked you to pick up? Chances are, you won't. Researchers have found that when it comes to memory, we don't remember things we hear nearly as well as things we see or touch.

Harvested rainwater harbors pathogens

Posted: 26 Feb 2014 01:53 PM PST

South Africa has been financing domestic rainwater harvesting tanks in informal low-income settlements and rural areas in five of that nation's nine provinces. But pathogens inhabit such harvested rainwater, potentially posing a public health hazard, especially for children and immunocompromised individuals, according to a research team. Many of the pathogens are normal fresh water inhabitants, but Salmonella (6% of samples) indicates human fecal contamination, while Yersinia are markers of fecal contamination by wild and domestic animals, according to the report.

Climate change: No warming hiatus for extreme hot temperatures

Posted: 26 Feb 2014 01:53 PM PST

While there are claims that there has been a hiatus in global average temperatures, no such hiatus has occurred at the extreme end of the temperature spectrum. New research shows extremely hot temperatures over land have dramatically and unequivocally increased in number and area despite claims that the rise in global average temperatures has slowed over the past 10 to 20 years.

Father's age tied to higher rates of psychiatric, academic problems in kids

Posted: 26 Feb 2014 01:53 PM PST

Advancing paternal age can lead to higher rates of psychiatric and academic problems in offspring than previously estimated. Compared to a children born to a 24-year-old father, children born to a 45-year-old father are 3.5 times more likely to have autism, 13 times more likely to have ADHD, twice as likely to have psychotic disorders and 25 times more likely to have bipolar disorder.

Antarctic circumpolar current carries 20 percent more water than previous estimates

Posted: 26 Feb 2014 01:51 PM PST

By analyzing four years of continuous measurements of the Antarctic Circumpolar Current at Drake Passage, the narrowest point in the Southern Ocean, oceanographers have concluded that the current carries 20 percent more water than previous estimates. They also found that the current remains strong all the way to the seafloor.

Phony honey a sweet deal for counterfeiters, bad for consumers

Posted: 26 Feb 2014 01:51 PM PST

Consumers buying honey might not be getting what they pay for according to one of the world's leading honey experts, who is supporting a U.S. Senate bill that would, if passed, put more stringent requirements on the federal government to ensure the origin of imported honey and compel sellers to label it accurately.

New mechanism of gene regulation, enzyme use in cells discovered

Posted: 26 Feb 2014 12:56 PM PST

In the cells of humans and other organisms, only a subset of genes are active at any given time, depending largely on the stage of life and the particular duties of the cell. Cells use different molecular mechanisms to orchestrate the activation and deactivation of genes as needed. One central mechanism is an intricate DNA packaging system that either shields genes from activation or exposes them for use. New research now provides additional insight into how cancer cells use the PARP1 enzyme in this process to resist current therapies, and may point to the next generation of cancer drugs.

Research maze puts images on floor, where rodents look

Posted: 26 Feb 2014 12:56 PM PST

Visual acuity is sharpest for rats and mice when the animals are looking down. Researchers have found that rodents can learn tasks in a fourth to a sixth of the usual number of repetitions when visual stimuli are projected onto the floor of the maze rather than onto the walls. The maze in this study is part real and part virtual. There are actual walls -- often in the shape of a giant piece of farfalle -- but researchers can project any imagery they want onto the floor from below. The use of digital projections makes the maze versatile, but using the floor for projections makes it particularly well-designed for rodent subjects.

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