A team of physicists has, for the first time, seen convincing experimental evidence for directed percolation, a phenomenon that turns up in computer models of the ways diseases spread through a population or how water soaks through loose soil. Their observation strengthens the case for directed percolation's relevance to real systems, and lends new vigor to long-standing theories about how it works.
Earth
WEST LAFAYETTE, Ind. - A new study indicates that major chemicals most often cited as leading causes of climate change, such as carbon dioxide and methane, are outclassed in their warming potential by compounds receiving less attention.
Purdue University and NASA examined more than a dozen chemicals, most of which are generated by humans, and have developed a blueprint for the underlying molecular machinery of global warming. The results appear in a special edition of the American Chemical Society's Journal of Physical Chemistry A, released Nov. 12.
The researchers studied bristlecone pines (Pinus longaeva) at three sites in California and Nevada, close to the upper elevation limit of tree growth. The tree-ring record showed wider rings in recent decades, indicating a surge in growth in the second half of the 20th century that was greater than at any time in the last 3,700 years.
NEW YORK (NOVEMBER 16, 2009) -- Recording hundreds of thousands of individual uplinks from satellite transmitters fitted on penguins, albatrosses, sea lions, and other marine animals, the Wildlife Conservation Society (WCS) and BirdLife International have released the first-ever atlas of the Patagonian Sea – a globally important but poorly understood South American marine ecosystem.
A dangerous level of carbon dioxide and methane gas haunts Lake Kivu, the freshwater lake system bordering Rwanda and the Republic of Congo.
Scientists can't say for sure if the volatile mixture at the bottom of the lake will remain still for another 1,000 years or someday explode without warning. In a region prone to volcanic and seismic activity, the fragility of Lake Kivu is a serious matter. Compounding the precarious situation is the presence of approximately 2 million people, many of them refugees, living along the north end of the lake.
Spurred by a warming climate, daily record high temperatures occurred twice as often as record lows over the last decade across the continental United States, new research shows.
The ratio of record highs to lows is likely to increase dramatically in coming decades if emissions of greenhouse gases continue to climb.
Satellite observations and a state-of-the art regional atmospheric model have independently confirmed that the Greenland ice sheet is loosing mass at an accelerating rate, reports a new study in Science.
Alberta is crisscrossed with hidden glacial valleys that hold both resource treasures and potential danger. University of Alberta researcher Doug Schmitt discovered a 300 metre deep, valley hidden beneath the surface of the ground near the community of Rainbow Lake in northwestern Alberta.
The valley was created by glaciers and over time filled with loose rock gradually disappearing from the landscape.
The performance of modern electronics increases steadily on a fast pace thanks to the ongoing miniaturization of the utilized components. However, se-vere problems arise due to quantum-mechanical phenomena when conven-tional structures are simply made smaller and reach the nanometer scale. Therefore current research focuses on the so-called bottom-up approach: the engineering of functional structures with the smallest possible building blocks - single atoms and molecules.
Long-term variations in volcanism help explain the birth, evolution and death of striking geological features called oceanic core complexes on the ocean floor, says geologist Dr Bram Murton of the National Oceanography Centre, Southampton.
Oceanic core complexes are associated with faults along slow-spreading mid-ocean ridges. They are large elevated massifs with flat or gently curved upper surfaces and prominent corrugations called 'megamullions'. Uplifting during their formation causes exposure of lower crust and mantle rocks on the seafloor.
In an advance that could help ease health and environmental concerns about the emerging nanotechnology industry, scientists are reporting development of technology for changing the behavior of nanoparticles in municipal sewage treatment plants — their main gateway into the environment. Their study will be published online November 12 in ACS' journal Environmental Science & Technology.
University of California, Berkeley, chemists have discovered the secret to the success of a jellyfish protein whose green glow has made it the darling of biologists and the subject of the 2008 Nobel Prize in Physiology or Medicine.
The researchers' study of green fluorescent protein (GFP) and the structural changes it undergoes when it fluoresces is the cover story of the Nov. 12 issue of the journal Nature.
The Earth's climate was far cooler – perhaps more than 50 degrees – billions of years ago, which could mean conditions for life all over the planet were more conducive than previously believed, according to a research team that includes a Texas A&M University expert who specializes in geobiology.
Fossil plants are windows to the past, providing us with clues as to what our planet looked like millions of years ago. Not only do fossils tell us which species were present before human-recorded history, but they can provide information about the climate and how and when lineages may have dispersed around the world. Identifying fossil plants can be tricky, however, when plant organs fail to be preserved or when only a few sparse parts can be found.
California experienced centuries-long droughts in the past 20,000 years that coincided with the thawing of ice caps in the Arctic, according to a new study by UC Davis doctoral student Jessica Oster and geology professor Isabel Montañez.
The finding, which comes from analyzing stalagmites from Moaning Cavern in the central Sierra Nevada, was published online Nov. 5 in the journal Earth and Planetary Science Letters.