Πέμπτη 23 Ιανουαρίου 2014

ScienceDaily: Top Science News

ScienceDaily: Top Science News


Galaxies on FIRE: Star feedback results in less massive galaxies

Posted: 22 Jan 2014 12:39 PM PST

For decades, astrophysicists have encountered a contradiction: although many galactic-wind models -- simulations of how matter is distributed in our universe -- predict that most matter exists in stars at the center of galaxies, in actuality these stars account for less than 10 percent of the matter in the universe. New simulations offer insight into this mismatch between the models and reality: energy released by individual stars can have a substantial effect on where matter ends up.

Differences in mammal responses to climate change demonstrated

Posted: 22 Jan 2014 10:42 AM PST

Large mammals are responding more to human-caused climate change than small mammals, according to a new assessment.

Humanity's most common male ancestor emerged earlier than thought: 209,000 years ago, study finds

Posted: 22 Jan 2014 10:41 AM PST

Our most common male ancestor emerged some 209,000 years ago -- earlier than many scientists previously thought, according to new research.

Bright star reveals new Neptune-size exoplanet

Posted: 22 Jan 2014 10:40 AM PST

A team of astronomers has discovered a new exoplanet, christened Kepler-410A b. The planet is about the size of Neptune and orbits the brightest star in a double star system 425 light years from Earth.

Herschel telescope detects water on dwarf planet in asteroid belt

Posted: 22 Jan 2014 10:25 AM PST

Scientists using the Herschel space observatory have made the first definitive detection of water vapor on the largest and roundest object in the asteroid belt, Ceres. Plumes of water vapor are thought to shoot up periodically from Ceres when portions of its icy surface warm slightly. Ceres is classified as a dwarf planet, a solar system body bigger than an asteroid and smaller than a planet.

Polar bear diet changes as sea ice melts

Posted: 22 Jan 2014 07:40 AM PST

At least some polar bears in the western Hudson Bay population are using flexible foraging strategies while on land, such as prey-switching and eating a mixed diet of plants and animals, as they survive in their rapidly changing environment, new research suggests.

Analysis of salamander jump reveals an unexpected twist

Posted: 22 Jan 2014 07:25 AM PST

A small, secretive creature with unlikely qualifications for defying gravity may hold the answer to an entirely new way of getting off the ground. Analysis of high-speed film reveals how salamanders —- or at least several species of the Plethodontidae family -— achieve vertical lift.

Parental exposure to marijuana linked to drug addiction, compulsive behavior in unexposed progeny, rodent sudy finds

Posted: 22 Jan 2014 07:25 AM PST

Teen marijuana use may have repercussions in unexposed progeny. This rodent study found that parental use of marijuana/THC was linked to molecular and neurobiological disturbances and increased motivation to get drugs.

Famine, not calcium absorption, may have driven evolution of milk tolerance in Europeans

Posted: 22 Jan 2014 06:18 AM PST

Ancient DNA from early Iberian farmers shows that the wideheld evolutionary hypothesis of calcium absorption was not the only reason Europeans evolved milk tolerance. In the West, people take milk drinking for granted because most people of European decent are able to produce the enzyme lactase in adulthood and so digest the milk sugar lactose. However, this is not the norm in much of the world, and was not the norm for our Stone Age ancestors.

Fever-reducing meds may help spread the flu

Posted: 22 Jan 2014 06:13 AM PST

Researchers assembled information from many sources, including experiments on human volunteers and on ferrets, then used a mathematical model to compute how the increase in the amount of virus given off by a single person taking fever-reducing drugs would increase the overall number of cases in a typical year. The bottom line is that fever suppression increases the number of annual cases by approximately 5%, corresponding to more than 1,000 additional deaths from influenza in a typical year across North America.

Engineers create light-activated 'curtains'

Posted: 21 Jan 2014 04:26 PM PST

Forget remote-controlled curtains. A new development could lead to curtains and other materials that move in response to light, no batteries needed.

E-whiskers: Highly sensitive tactile sensors developed for robotics and other applications

Posted: 21 Jan 2014 04:14 PM PST

From the world of nanotechnology we've gotten electronic skin, or e-skin, and electronic eye implants or e-eyes. Now we're on the verge of electronic whiskers. Researchers have created tactile sensors from composite films of carbon nanotubes and silver nanoparticles similar to the highly sensitive whiskers of cats and rats. These new e-whiskers respond to pressure as slight as a single Pascal, about the pressure exerted on a table surface by a dollar bill. Among their many potential applications is giving robots new abilities to "see" and "feel" their surrounding environment.

How the genetic blueprints for limbs came from fish

Posted: 21 Jan 2014 03:34 PM PST

Our first four-legged land ancestor came out of the sea some 350 million years ago. Watching a lungfish, our closest living fish relative, crawl on its four pointed fins gives us an idea of what the first evolutionary steps on land probably looked like. However, the transitional path between fin structural elements in fish and limbs in tetrapods remains elusive. Both fish and land animals possess clusters of Hoxa and Hoxd genes, which are necessary for both fin and limb formation during embryonic development. Scientists compared the structure and behavior of these gene clusters in embryos from mice and zebrafish. The researchers discovered similar 3-dimensional DNA organization of the fish and mouse clusters, which indicates that the main mechanism used to pattern tetrapod limbs was already present in fish.

Turkeys inspire smartphone-capable early warning system for toxins

Posted: 21 Jan 2014 08:34 AM PST

Bioengineers looked to turkeys for inspiration when developing a new type of biosensor that changes color when exposed to chemical vapors. They mimicked the way turkey skin changes color to create easy-to-read sensors that can detect toxins or airborne pathogens.

Pathogenic plant virus jumps to honeybees, may explain bee population decline

Posted: 21 Jan 2014 06:30 AM PST

A viral pathogen that typically infects plants has been found in honeybees and could help explain their decline. Researchers working in the U.S. and Beijing, China report their findings in a recently published article.

New discoveries show biological formation of oxygen in soils

Posted: 21 Jan 2014 06:29 AM PST

In the 1930s, the ability of green plants to form oxygen through oxidation of water -- photosynthesis -- was discovered. Since then, no other large-scale biological formation of oxygen has been found, until now. New research results show that down in the dark depths of the soil, a previously unknown biochemical process is under way, in which oxygen is formed and carbon dioxide is reduced to organic material.

Vancouver: Nearby Georgia basin may amplify ground shaking from next quake

Posted: 20 Jan 2014 02:34 PM PST

Tall buildings, bridges and other long-period structures in Greater Vancouver may experience greater shaking from large earthquakes than previously thought due to the amplification of surface waves passing through the Georgia basin, according to two new studies. The basin will have the greatest impact on ground motion passing over it from earthquakes generated south and southwest of Vancouver.

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