Παρασκευή 31 Αυγούστου 2012

ScienceDaily: Top Environment News

ScienceDaily: Top Environment News


Shading Earth: Delivering solar geoengineering materials to combat global warming may be feasible and affordable

Posted: 30 Aug 2012 04:10 PM PDT

A cost analysis of the technologies needed to transport materials into the stratosphere to reduce the amount of sunlight hitting Earth and therefore reduce the effects of global climate change has shown that they are both feasible and affordable. The study has shown that the basic technology currently exists and could be assembled and implemented in a number of different forms for less than USD $5 billion a year.

Mystery of operon evolution probed

Posted: 30 Aug 2012 02:35 PM PDT

New research suggests a possible explanation for the organization of operons, jointly controlled clusters of genes that evolved in bacterial chromosomes. Operons, which are found in the chromosomes of bacteria but not in more advanced organisms, have puzzled biologists since their discovery in the 1960s. The new study suggests operons evolved as a means of reducing "noise" in biochemical signal processing.

Biophysicists unravel secrets of genetic switch

Posted: 30 Aug 2012 02:33 PM PDT

Biophysicists have experimentally demonstrated, for the first time, how the nonspecific binding of a protein known as the lambda repressor, or C1 protein, bends DNA and helps it close a loop that switches off virulence. Findings are the first direct and quantitative determination of non-specific binding and compaction of DNA, relevant for the understanding of DNA physiology, and the dynamic characteristics of an on-off switch for the expression of genes.

Surviving drought: Discovery may help protect crops from stressors

Posted: 30 Aug 2012 02:31 PM PDT

New findings of a key genetic mechanism in plant hormone signaling may help save crops from stress and help address human hunger.

Microbes help hyenas communicate via scent

Posted: 30 Aug 2012 12:23 PM PDT

Bacteria in hyenas' scent glands may be the key controllers of communication. New research shows a clear relationship between the diversity of hyena clans and the distinct microbial communities that reside in their scent glands.

'Promiscuous' enzymes still prevalent in metabolism: Challenges fundamental notion of enzyme specificity and efficiency

Posted: 30 Aug 2012 12:23 PM PDT

Open an undergraduate biochemistry textbook and you will learn that enzymes are highly efficient and specific in catalyzing chemical reactions in living organisms, and that they evolved to this state from their "sloppy" and "promiscuous" ancestors to allow cells to grow more efficiently. This fundamental paradigm is being challenged in a new study by bioengineers who reported in the journal Science what a few enzymologists have suspected for years: many enzymes are still pretty sloppy and promiscuous, catalyzing multiple chemical reactions in living cells, for reasons that were previously not well understood.

Moving toward regeneration

Posted: 30 Aug 2012 12:23 PM PDT

Scientists have shown how pluripotent stem cells mobilize in wounded planarian worms, to better understand stem cell behavior in regeneration and disease.

Monogamy and the immune system: Differences in sexual behavior impact bacteria hosted and genes that control immunity

Posted: 30 Aug 2012 11:14 AM PDT

Researchers examined the differences between two species of mice -- one monogamous and one promiscuous -- on a microscopic and molecular level. They discovered that the lifestyles of the two mice had a direct impact on the bacterial communities that reside within the female reproductive tract. These differences correlate with enhanced diversifying selection on genes related to immunity against bacterial diseases.

Plants' fungi allies may not help store climate change's extra carbon

Posted: 30 Aug 2012 11:13 AM PDT

Fungi found in plants may not be the answer to mitigating climate change by storing additional carbon in soils as some previously thought, according to plant biologists.

Human and soil bacteria swap antibiotic-resistance genes

Posted: 30 Aug 2012 11:13 AM PDT

Soil bacteria and bacteria that cause human diseases have recently swapped at least seven antibiotic-resistance genes, researchers at Washington University School of Medicine in St. Louis report Aug. 31 in Science.

'Weird chemistry' by microbe is prime source of ocean methane

Posted: 30 Aug 2012 11:13 AM PDT

Up to four percent of the methane on Earth comes from the ocean's oxygen-rich waters, but scientists have been unable to identify the source of this potent greenhouse gas. Now researchers report that they have found the culprit: A bit of "weird chemistry" practiced by the most abundant microbes on the planet.

Heating by black carbon aerosol: Soot particles absorb significantly less sunlight than predicted by models

Posted: 30 Aug 2012 11:13 AM PDT

Black carbon, in the form of soot particles, has been ranked just behind carbon dioxide for its role in warming regional and global climates. But a new study finds airborne black carbon absorbs significantly less sunlight than scientists had predicted, leading an international team of researchers to reconsider the impact of soot on atmospheric warming.

Evolution of mustards' spice: Plants developed chemical defense against bugs, specific to where they live

Posted: 30 Aug 2012 11:13 AM PDT

The tangy taste a mustard plant develops to discourage insect predators can be the difference between life and death for the plants. A new study has used this trait and its regional variations to conquer the difficult task of measuring the evolution of complex traits in a natural environment.

Ancient Denisovan genome: Relationships between Denisovans and present-day humans revealed

Posted: 30 Aug 2012 11:12 AM PDT

Researchers have described the Denisovan genome, illuminating the relationships between Denisovans and present-day humans.

Uncoiling the cucumber's enigma: Biological mechanism for coiling, and unusual type of spring discovered

Posted: 30 Aug 2012 11:12 AM PDT

In the creeping plant's tendrils, researchers discover a biological mechanism for coiling and stumble upon an unusual type of spring.

No-till farming helps capture snow and soil water

Posted: 30 Aug 2012 10:04 AM PDT

A smooth blanket of snow in the winter can help boost dryland crop productivity in the summer, and no-till management is one way to ensure that blanket coverage, according to new research.

Viruses could be the key to healthy corals

Posted: 30 Aug 2012 10:04 AM PDT

Scientists have developed a treatment for the white plague disease that infects coral based on a medication developed to treat bacterial infections in humans. The therapy ceased the progression of infection in diseased corals and prevented the infection from spreading to surrounding healthy corals as well.

Increased sediment and nutrients delivered to bay as Susquehanna reservoirs near sediment capacity

Posted: 30 Aug 2012 10:00 AM PDT

Reservoirs near the mouth of the Susquehanna River just above Chesapeake Bay, Maryland, U.S. are nearly at capacity in their ability to trap sediment. As a result, large storms are already delivering increasingly more suspended sediment and nutrients to the Bay, which may negatively impact restoration efforts.

Millipede family added to Australian fauna

Posted: 30 Aug 2012 10:00 AM PDT

An entire group of millipedes previously unknown in Australia has been discovered by a specialist – on museum shelves. Hundreds of tiny specimens of the widespread tropical family Pyrgodesmidae have been found among bulk samples in two museums, showing that native pyrgodesmids are not only widespread in Australia's tropical and subtropical forests, but are also abundant and diverse. The study has been published in the open access journal ZooKeys.

Coral scientists use new model to find where corals are most likely to survive climate change

Posted: 30 Aug 2012 07:54 AM PDT

Marine conservationists have identified heat-tolerant coral species living in locations with continuous background temperature variability as those having the best chance of surviving climate change, according to a new simplified method for measuring coral reef resilience.

New DNA method tracks fish and whales in seawater

Posted: 30 Aug 2012 07:54 AM PDT

Future monitoring of marine biodiversity and resources may use DNA traces in seawater samples to keep track of fish and whales in the oceans. A half liter of seawater can contain evidence of local fish and whale faunas and combat traditional fishing methods.

Five new species of cuckoo bees from the Cape Verde Islands

Posted: 30 Aug 2012 07:54 AM PDT

Researchers have documented a remarkable diversity of cuckoo bees in the Cape Verde Islands. All five discovered species are entirely new to science and highlight the unique biota of this isolated archipelago.

Carbon release from collapsing coastal permafrost in Arctic Siberia

Posted: 30 Aug 2012 07:53 AM PDT

A new study shows that an ancient and large carbon pool held in a less-studied form of permafrost ("Yedoma") is thaw-released along the approximately 7000-kilometer desolate coast of northernmost Siberian Arctic. 

Keep your distance: Why cells and organelles don't get stuck

Posted: 30 Aug 2012 07:28 AM PDT

Biomembranes enclose biological cells like a skin. They also surround organelles that carry out important functions in metabolism and cell division. Scientists have long known in principle how biomembranes are built up, and also that water molecules play a role in maintaining the optimal distance between neighboring membranes -- otherwise they could not fulfill their vital functions. Now, with the help of computer simulations, scientists have discovered two different mechanisms that prevent neighboring membrane surfaces from sticking together.

Conservation scientists call policy-makers to be scale-aware

Posted: 30 Aug 2012 05:33 AM PDT

Conservation is concerned with the preservation of biological diversity at all levels, from genes to species, communities and ecosystems.  Yet conserving this biological richness is made difficult because it varies in complex ways at different scales of space and time. The problem of scale emerges as a critical new theme in conservation practice.

A slow-moving Isaac brings flooding to Gulf states

Posted: 30 Aug 2012 04:46 AM PDT

Isaac -- once a Category 1 hurricane and now a strong tropical storm with maximum sustained winds of 70 miles per hour (60 knots) -- continues to create havoc across the Gulf Coast, from eastern Texas to Florida. While "only" reaching Category 1 on the Saffir-Simpson hurricane wind scale upon landfall on Aug. 28, Isaac is a slow mover, crawling along at only about six miles (10 kilometers) per hour. This slow movement is forecast to continue over the next 24 to 36 hours, bringing a prolonged threat of flooding to the northern Gulf Coast and south-central United States.

Ecological monitoring on bird populations in Europe re-evaluated

Posted: 30 Aug 2012 03:58 AM PDT

A new article has examined Europe's long experience in monitoring the populations of birds. Scientists calculated that nearly 28,000 persons have been involved in bird monitoring during last few years, investing on average some 80,000 person days per year. Several recommendations for improving bird monitoring are proposed.

Can blue tits can save our conker trees?

Posted: 30 Aug 2012 03:57 AM PDT

Blue tits, a familiar garden bird in the U.K., could be the salvation of our imperiled conker trees (horse-chestnut trees), which are under severe attack by a tiny non-native moth that has spread from continental Europe.

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