Plant leaves are photosynthetic organs. Their main job is to harvest energy from sunlight, and use that energy to convert carbon dioxide and water into carbohydrates. In addition to capturing sunlight, leaves need to be good at doing two other things - taking up carbon dioxide and conserving water. These requirements conflict - anything that lets carbon dioxide in also lets water out. To deal with these conflicting requirements, plants produce a waterproof cuticle and regulate carbon dioxide uptake by opening and closing their stomata.

Modern diesel cars are quieter than their predecessors but also release considerably fewer exhaust fumes into the atmosphere.

But the real culprit in diesel are heavy-duty, construction and off-road vehicles - they're often special vehicles made in small batches and each requires a different filter geometry. The filters for are not yet state-of-the-art. A new diesel particulate filter technology will soon teach even these vehicles to give up smoking.

Conventional diesel soot filters usually consist of cylindrical ceramic blocks crisscrossed by numerous channels. A block of this kind cannot be made in one piece. Instead, individual quadratic honeycomb segments are bonded together to form a large block.

The RoboSwift micro-aircraft has made its first flight. The small, quiet plane is equipped with observation cameras that can be used in the future to study birds or to conduct surveillance of groups of people or vehicles.

The RoboSwift is characterised by the continuously variable shape of its wings, known as ‘morphing' wings, which are modelled on the wings of the swift bird. These wings make the aircraft, like its living model, very maneuverable and efficient. As a result, the RoboSwift is the first aircraft in the world to have the wing properties of living birds. Wind tunnel tests have shown that it can come remarkably close to the exceptional flying ability of the swift.

A combination of negative mother-daughter relationships and low blood levels of serotonin, an important brain chemical for mood stability, may be lethal for adolescent girls, leaving them vulnerable to engage in self-harming behaviors such as cutting themselves.

New University of Washington research indicates that these two factors in combination account for 64 percent of the difference among adolescents, primarily girls, who engage in self-harming behaviors and those who do not.

“Girls who engage in self harm are at high risk for attempting suicide, and some of them are dying,” said Theodore Beauchaine, a UW associate professor of psychology and co-author of a new study. “There is no better predictor of suicide than previous suicide attempts.”

Solving a long-standing biological mystery, UCLA stem cell researchers have discovered that blood stem cells, the cells that later differentiate into all the cells in the blood supply, originate and are nurtured in the placenta.

The discovery may allow researchers to mimic the specific embryonic microenvironment necessary for development of blood stem cells in cell culture and grow them for use in treating diseases like leukemia and aplastic anemia, said Dr. Hanna Mikkola, a researcher in the Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research and senior author of the study.

People who handle explosives usually have heavy-duty tasks to perform – dislodging rocks, demolishing old buildings, or triggering an avalanche. Now explosives can be used for delicate tasks, too, like making it possible to place holograms in steel.

Nearly everybody carries holograms around on light things, like money or tickets for a concert, because they protect against forgery. They take a great deal of effort to produce, and are almost impossible to copy, because the image is created not only by the interaction of different colors and contrasts, but also by the surface structure. Different pictures can be seen, depending on the direction from which the light is shining.

What do oil exploration and steroid testing have in common? Quite a bit, say researchers at The University of Nottingham.

Their new process — which uses high pressure environments to investigate the chemical structure and make-up of a sample — has been refined and developed at the University to develop highly accurate tests for detecting levels of illicit steroids in urine. The test procedure is already in the process of being commercialised and is expected to be ready for use in the 2012 Olympics.

A new modeling approach using sea ice motion data to follow parcels of ice backward in time at monthly intervals for up to 3 years while accumulating a history of the solar radiation and air temperature to which the ice was exposed offers new hope for increased accuracy in climate change models, say scientists with the U.S. Geological Survey and the Russian Academy of Sciences, Moscow. This is the only model based entirely on historical observations.

Using this new technique, the thickness of Arctic sea ice was estimated from 1982 to 2003. Results showed that average ice thickness and total ice volume fluctuated together during the early study period, peaking in the late 1980s and then declining until the mid-1990s. Thereafter, ice thickness slightly increased but the total volume of sea ice did not increase.

A 10-cent pill doesn't kill pain as well as a $2.50 pill, even when they are identical placebos, according to a provocative study by Dan Ariely, a behavioral economist at Duke University.

"Physicians want to think it's the medicine and not their enthusiasm about a particular drug that makes a drug more therapeutically effective, but now we really have to worry about the nuances of interaction between patients and physicians," said Ariely, whose findings appear as a letter in the Journal of the American Medical Association.

Objectives.

Sepsis is a syndrome that results from a dysregulated host response to infection which can rapidly lead to organ dysfunction and death.
The aim of this study was the microbiological and clinical assessment of a new real-time PCR test (SeptiFast: SF, Roche Diagnostics) for the diagnosis of blood stream infections (BSI) in a population of neutropenic patients.
The results of SF were compared with blood cultures (BC) obtained on the same specimens and the clinical significance of the two methods was assessed.

Methods.