Πέμπτη, 24 Απριλίου 2014

ScienceDaily: Top Science News

ScienceDaily: Top Science News


Drought may take toll on Congo rainforest, NASA satellites show

Posted: 23 Apr 2014 02:09 PM PDT

A new analysis of NASA satellite data shows Africa's Congo rainforest, the second-largest tropical rainforest in the world, has undergone a large-scale decline in greenness over the past decade. Scientists use the satellite-derived "greenness" of forest regions as one indicator of a forest's health. While this study looks specifically at the impact of a persistent drought in the Congo region since 2000, researchers say that a continued drying trend might alter the composition and structure of the Congo rainforest, affecting its biodiversity and carbon storage.

Rural microbes could boost city dwellers' health, study finds

Posted: 23 Apr 2014 02:09 PM PDT

The greater prevalence of asthma, allergies and other chronic inflammatory disorders among people of lower socioeconomic status might be due in part to their reduced exposure to the microbes that thrive in rural environments, according to a new scientific paper.

Male or female? First sex-determining genes appeared in mammals some 180 million years ago

Posted: 23 Apr 2014 12:10 PM PDT

The Y chromosome, which distinguishes males from females at the genetic level, appeared some 180 million years ago. It originated twice independently in all mammals. Scientists have managed to date these events that are crucial for both mammalian evolution and our lives, because the Y chromosome determines whether we are born as a boy or girl.

Superconducting qubit array points the way to quantum computers

Posted: 23 Apr 2014 12:10 PM PDT

A fully functional quantum computer is one of the holy grails of physics. Physicists have moved one step closer to making a quantum computer a reality by demonstrating a new level of reliability in a five-qubit array. Quantum computing is anything but simple. It relies on aspects of quantum mechanics such as superposition. This notion holds that any physical object, such as an atom or electron -- what quantum computers use to store information -- can exist in all of its theoretical states simultaneously. This could take parallel computing to new heights.

Hearing quality restored with bionic ear technology used for gene therapy: Re-growing auditory nerves

Posted: 23 Apr 2014 11:30 AM PDT

Researchers have for the first time used electrical pulses delivered from a cochlear implant to deliver gene therapy, thereby successfully regrowing auditory nerves. The research also heralds a possible new way of treating a range of neurological disorders, including Parkinson's disease, and psychiatric conditions such as depression through this novel way of delivering gene therapy.

Scientists identify source of mysterious sound in the Southern Ocean

Posted: 23 Apr 2014 10:26 AM PDT

Scientists have conclusive evidence that the source of a unique rhythmic sound, recorded for decades in the Southern Ocean and called the 'bio-duck,' is the Antarctic minke whale (Balaenoptera bonaerensis). First described and named by submarine personnel in the 1960s who thought it sounded like a duck, the bio-duck sound has been recorded at various locations in the Southern Ocean, but its source has remained a mystery, until now.

Odds of storm waters overflowing Manhattan seawall up 20-fold

Posted: 23 Apr 2014 10:26 AM PDT

Maximum water levels in New York harbor during major storms have risen by nearly two and a half feet since the mid-1800s, making the chances of water overtopping the Manhattan seawall now at least 20 times greater than they were 170 years ago, according to a new study.

Hundreds of genetic mutations found in healthy blood of a supercentenarian

Posted: 23 Apr 2014 10:26 AM PDT

Genetic mutations are commonly studied because of links to diseases such as cancer; however, little is known about mutations occurring in healthy individuals. Researchers have now detected over 400 mutations in healthy blood cells of a 115-year-old woman, suggesting that lesions at these sites are largely harmless over the course of a lifetime.

From liability to viability: Genes on the Y chromosome prove essential for male survival

Posted: 23 Apr 2014 10:24 AM PDT

The human Y chromosome has, over the course of millions of years of evolution, preserved a small set of genes that has ensured not only its own survival but also the survival of men. Moreover, the vast majority of these tenacious genes appear to have little if any role in sex determination or sperm production. Taken together, these remarkable findings suggest that because these Y-linked genes are active across the body, they may actually be contributing to differences in disease susceptibility and severity observed between men and women.

Surface area of the digestive tract much smaller than previously thought

Posted: 23 Apr 2014 08:15 AM PDT

The internal surface area of the gastro-intestinal tract has long been considered to be between 180 and 300 square meters. Scientists have used refined microscopic techniques that indicate a much smaller area. "Actually, the inner surface of the gastro-intestinal tract is only as large as a normal studio apartment," says one scientist.

Political ravens? Ravens notice the relationships among others, study shows

Posted: 23 Apr 2014 07:19 AM PDT

Cognitive biologists have revealed that ravens do understand and keep track of the rank relations between other ravens. Such an ability has been known only from primates. Like many social mammals, ravens form different types of social relationships -- they may be friends, kin, or partners and they also form strict dominance relations. From a cognitive perspective, understanding one's own relationships to others is a key ability in daily social life ("knowing who is nice or not"). Yet, also understanding the relationships group members have with each other sets the stage for "political" maneuvers ("knowing who might support whom").

Liquid spacetime: What if spacetime were a kind of fluid?

Posted: 23 Apr 2014 06:52 AM PDT

What if spacetime were a kind of fluid? This is the question tackled by theoretical physicists working on quantum gravity by creating models attempting to reconcile gravity and quantum mechanics. Some of these models predict that spacetime at the Planck scale is no longer continuous – as held by classical physics – but discrete in nature. Just like the solids or fluids we come into contact with every day, which can be seen as made up of atoms and molecules when observed at sufficient resolution. A structure of this kind generally implies, at very high energies, violations of Einstein's special relativity (a integral part of general relativity).

Brain circuits involved in emotion discovered by neuroscientists

Posted: 22 Apr 2014 05:23 PM PDT

A brain pathway that underlies the emotional behaviors critical for survival have been discovered by neuroscientists. The team has identified a chain of neural connections which links central survival circuits to the spinal cord, causing the body to freeze when experiencing fear. Understanding how these central neural pathways work is a fundamental step towards developing effective treatments for emotional disorders such as anxiety, panic attacks and phobias.

Cougars’ diverse diet helped them survive the mass extinction that wiped out the saber-tooth cat, American lion

Posted: 22 Apr 2014 05:20 PM PDT

Cougars may have survived the mass extinction that took place about 12,000 years ago because they were not particular about what they ate, unlike their more finicky cousins the saber-tooth cat and American lion who perished, according a new analysis of the microscopic wear marks on the teeth of fossil cougars, saber-tooth cats and American lions.

New electric fish genus, species discovered in Brazil's Rio Negro

Posted: 22 Apr 2014 09:12 AM PDT

Discovery of a new species of electric knife fish in the Amazon Basin in Brazil is leading to a new interpretation of classifications and interrelationships among closely related groups. As the diversity of electric fishes becomes more thoroughly documented, researchers will be able to explore possible causes of this group's adaptive radiation over evolutionary time.

Cow manure harbors diverse new antibiotic resistance genes

Posted: 22 Apr 2014 05:49 AM PDT

Manure from dairy cows, which is commonly used as a farm soil fertilizer, contains a surprising number of newly identified antibiotic resistance genes from the cows' gut bacteria. The findings hints that cow manure is a potential source of new types of antibiotic resistance genes that transfer to bacteria in the soils where food is grown. "Is this a route for movement of these genes from the barn to the table?" asks the senior study author.

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