Παρασκευή 22 Φεβρουαρίου 2013

ScienceDaily: Top Environment News

ScienceDaily: Top Environment News


NASA deciphering the mysterious math of the solar wind

Posted: 21 Feb 2013 06:46 PM PST

The sun and its prodigious stream of solar particles, called the solar wind, can be particularly tricky to model since as the material streams to the outer reaches of the solar system it carries along its own magnetic fields. The magnetic forces add an extra set of laws to incorporate when trying to determine what's governing the movement. Indeed, until now, equations for certain aspects of the solar wind have never been successfully devised to correlate to the observations seen by instruments in space. Now, for the first time, a scientist at NASA's Goddard Space Flight Center has created a set of the necessary equations.

Why sourdough bread resists mold

Posted: 21 Feb 2013 04:42 PM PST

Sourdough bread resists mold, unlike conventionally leavened bread. Now scientists show why. During sourdough production, bacteria convert the linoleic acid in bread flour to a compound that has powerful antifungal activity.

‘Stressed’ bacteria become resistant to antibiotics

Posted: 21 Feb 2013 04:40 PM PST

Bacteria become resistant to antibiotics when stressed, finds new research. In particular E. coli grown at high temperatures become resistant to rifampicin. It is generally thought that antibiotic resistance is costly to maintain, for example mutations which reduce antibiotic uptake also restrict the amount of nutrients entering the cell. Consequently in the absence of antibiotics non-resistant bacteria will out-compete the resistant ones. However researchers have discovered that by putting bacteria under stress, by growing them at a high temperature, the bacteria could spontaneously develop resistance to the antibiotic rifampicin.

Conserving corals by understanding their genes

Posted: 21 Feb 2013 04:40 PM PST

In reef-building corals variations within genes involved in immunity and response to stress correlate to water temperature and clarity, finds a new study. This information could be used to conserve or rebuild reefs in areas affected by climate change, by changes in extreme weather patterns, increasing sedimentation or altered land use.

Particle physics research sheds new light on possible 'fifth force of nature'

Posted: 21 Feb 2013 04:27 PM PST

In a breakthrough for the field of particle physics, researchers have established new limits on what scientists call "long-range spin-spin interactions" between atomic particles. These interactions have been proposed by theoretical physicists but have not yet been seen. Their observation would constitute the discovery of a "fifth force of nature" (in addition to the four known fundamental forces: gravity, weak, strong and electromagnetic) and would suggest the existence of new particles, beyond those presently described by the Standard Model of particle physics.

Using amount of fish caught as measure of fisheries health is misleading

Posted: 21 Feb 2013 04:27 PM PST

Changes in the amount of fish caught does not necessarily reflect the number of fish in the sea.

New clues to Epstein-Barr virus

Posted: 21 Feb 2013 12:27 PM PST

Epstein-Barr virus (EBV) affects more than 90 percent of the population worldwide and was the first human virus found to be associated with cancer. Now, researchers have broadened the understanding of this widespread infection with their discovery of a second B-cell attachment receptor for EBV.

Robotic bat wing engineered: Researchers uncover flight secrets of real bats

Posted: 21 Feb 2013 11:39 AM PST

Researchers have developed a robotic bat wing that is providing valuable new information about dynamics of flapping flight in real bats. From an engineering perspective, the researchers hope the data may make for better aircraft, especially micro air vehicles. From a biological and evolutionary perspective, building the robot offered the researchers a new perspective on how bat anatomy is adapted to deal with the forces generated by flapping wings.

Geoengineering by coalition to mitigate global warming

Posted: 21 Feb 2013 11:39 AM PST

Solar geoengineering is a proposed approach to reduce the effects of climate change due to greenhouse gasses by deflecting some of the sun's incoming radiation. This type of proposed solution carries with it a number of uncertainties, however, including geopolitical questions about who would be in charge of the activity and its goals. New modeling work shows that if a powerful coalition ever decided to deploy a geoengineering system, they would have incentive to exclude other countries from participating in the decision-making process.

Caves point to thawing of Siberia: Thaw in Siberia's permafrost may accelerate global warming

Posted: 21 Feb 2013 11:39 AM PST

Evidence from Siberian caves suggests that a global temperature rise of 1.5 degrees Celsius could see permanently frozen ground thaw over a large area of Siberia, threatening release of carbon from soils, and damage to natural and human environments.

Floral signs go electric: Bumblebees find and distinguish electric signals from flowers

Posted: 21 Feb 2013 11:39 AM PST

Flowers' methods of communicating are at least as sophisticated as any devised by an advertising agency, according to a new study. The research shows for the first time that pollinators such as bumblebees are able to find and distinguish electric signals given out by flowers. However, for any advertisement to be successful, it has to reach, and be perceived by, its target audience.

Coldness triggers northward flight in monarch butterflies: Migration cycle may be vulnerable to global climate change

Posted: 21 Feb 2013 11:12 AM PST

Each fall millions of monarch butterflies migrate south in order to escape frigid temperatures, traveling up to 2,000 miles to an overwintering site in a specific grove of fir trees in central Mexico. A new study suggests that exposure to coldness found in the microenvironment of the monarch's overwintering site triggers their return north every spring. Without this cold exposure, the monarch butterfly would continue flying south.

Great Backyard Bird Count goes global, shatters records

Posted: 21 Feb 2013 06:18 AM PST

Bird watchers from 101 countries made history in the first global Great Backyard Bird Count, Feb. 15 to 18. In the largest worldwide bird count ever, bird watchers set new records, counting more than 25 million birds on 116,000 checklists in four days -- and recording 3,138 species, nearly one-third of the world's total bird species.

Earthquakes in small laboratory samples

Posted: 21 Feb 2013 05:47 AM PST

Mechanical failure of materials is a complex phenomenon underlying many accidents and natural disasters ranging from the fracture of small devices to earthquakes. Despite the vast separation of spatial, temporal, energy, and strain-rate scales, and the differences in geometry, it has been proposed that laboratory experiments on brittle fracture in heterogeneous materials can be a model for earthquake occurrence.

Common swifts make mysterious twilight ascents

Posted: 21 Feb 2013 05:47 AM PST

Common swifts climb to altitudes of up to 2.5 km both at dawn and dusk. This unexpected behavior was discovered by a geo-ecologist.

Bees attracted to contrasting colors when looking for nectar

Posted: 21 Feb 2013 05:47 AM PST

Flower colors that contrast with their background are more important to foraging bees than patterns of colored veins on pale flowers, according to new research. Researchers' observation of how patterns of pigmentation on flower petals influence bumblebees' behavior suggests that color veins give clues to the location of the nectar. There is little to suggest, however, that bees have an innate preference for striped flowers.

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