Earth

PROVIDENCE, R.I. [Brown University] — The cataclysmic events that marked the end of the Permian Period some 252 million years ago were a watershed moment in the history of life on Earth. As much as 90 percent of ocean organisms were extinguished, ushering in a new order of marine species, some of which we still see today. But while land dwellers certainly sustained major losses, the extent of extinction and the reshuffling afterward were less clear.

In this week's PLoS Medicine, Justin Lessler of the Johns Hopkins Bloomberg School of Public Health, Baltimore, USA and colleagues describe a method that estimates the fraction of a population accessible to vaccination activities, and apply it to measles vaccination in three African countries: Ghana, Madagascar, and Sierra Leone. Their estimates can be used to identify countries where problems in vaccine delivery may exist, thereby providing important operational guidance on how to improve vaccine coverage.

In this week's PLoS Medicine, the PLoS Medicine editors reflect on recent research and analysis into rapid and convenient diagnostic tests for tuberculosis and HIV. They argue that while improving the speed and convenience of diagnostic tests is important, fully evaluating diagnostics remains critical to ensure that technical improvements are translated into improved health outcomes.

The Greenland ice sheet can experience extreme melting even when temperatures don't hit record highs, according to a new analysis by Dr. Marco Tedesco, assistant professor in the Department of Earth and Atmospheric Sciences at The City College of New York. His findings suggest that glaciers could undergo a self-amplifying cycle of melting and warming that would be difficult to halt.

DALLAS (SMU) – New research from SMU's Geothermal Laboratory, funded by a grant from Google.org, documents significant geothermal resources across the United States capable of producing more than three million megawatts of green power – 10 times the installed capacity of coal power plants today.

Researchers studying how fluids travel through nanoscale channels were surprised to discover that the fluids don't flow equally well in all directions. Contrary to the behavior in the macroscale world, the researchers discovered that methyl alcohol, when it was placed in a network of nanoscale channels in a mineral known as a zeolite, diffused 1,000 times faster in one direction than another. This is the first known evidence of such highly unequal diffusion of molecules in a nanoporous material.

Pick your poison from this smorgasbord of recent salmonella outbreaks in the United States: ground turkey; fresh papayas; alfalfa sprouts. That's in 2011 alone, and the list goes on, according to the U.S. Centers for Disease Control and Prevention. But perhaps not for long, thanks to a promising new biosensor nanotechnology that could identify the presence of salmonella bacteria before contaminated food or animals reach the marketplace.

Oxford -- In the latest issue of Elsevier's Materials Today, researchers from Spain and Belgium reported on the innovative use of carbon nanotubes to create mechanical components for use in a new generation of micro-machines. While the electronics industry has excelled in miniaturizing components, with individual elements approaching the nanoscale (or a billionth of a meter), reducing the size of mechanical systems has proved much more challenging.

Biologists at the University of California, San Diego have succeeded in unraveling, for the first time, the complete chain of biochemical reactions that controls the synthesis of auxin, the hormone that regulates nearly all aspects of plant growth and development.

Their discovery, detailed in a paper in this week's online edition of the Proceedings of the National Academy of Sciences, will allow agricultural scientists to develop new ways to enhance or manipulate auxin production to improve the growth and yield of crops and other plants.

(CHICAGO) -- A 40-year search for a gene that causes some one-celled sea creatures to flash at night and is also found in others that produce deadly red tides, has been successfully culminated by a group of scientists led by Thomas E. DeCoursey, PhD, professor of biophysics and physiology at Rush University Medical Center.

Athens, Ga. – Increasing acidification in coastal waters could compromise the ability of oysters and other marine creatures to form and keep their shells, according to a new study led by University of Georgia researchers.

Their findings will be published in the November 2011 issue of Nature Geoscience. The researchers determined the combined effects of fertilizer runoff carried by the Mississippi River to the northern Gulf of Mexico and excess atmospheric carbon dioxide from burning fossil fuels result in an unexpected increase in the acidity of Gulf waters.

Nanoparticulate flow in a curved pipe differs to that in a straight pipe, and is of scientific and technological interest.

The length of flow path within a curved pipe is generally short, and the fluid experiences a centrifugal force which significantly changes the particle distribution both inside and downstream of the pipe. This phenomenon is more obvious when particle coagulation occurs. Prior to this study, nanoparticle migration in a rotating curved pipe with consideration of coagulation and dispersion has not been reported in detail.

"We have investigated the cycling of molybdenum (Mo) in ancient oceans by studying the elemental and isotopic composition of Mo in sedimentary rocks from Grand Canyon that formed in the oceans 750 million years ago", explains Tais W. Dahl, who did this research in collaboration with researchers from Arizona State University, Harvard University and the Nordic Center of Earth Evolution in Denmark (NordCEE).

Molybdenum tracks the presence of poisonous sulfide in ancient oceans

Introducing heterogeneities into the structure is an effective way to enhance the plasticity of metallic glasses (MGs). The original randomly distributed free volume in MGs, a natural heterogeneity, has been found to promote plasticity. However, the exact correlation between the free volume distribution and mechanical response is still unclear. Professor Dai Lanhong and his group from the State Key Laboratory of Nonlinear Mechanics, Institute of Mechanics, Chinese Academy of Sciences, set out to tackle this problem.

Soft matters maintain their structures via weak interactions, such as Van der Waals, capillary, hydrogen bonds etc. The entropy plays a key role in the ordering of this kind of materials. They behave as a solid until a sufficiently large stress is applied, and then behave as a viscoelastic liquid. Due to the unique structures and rheological properties, soft matter such as concentrated suspensions, emulsions, pastes and gels often exhibit unusual slow relaxation and aging effect.