August 16, 2007, 9:09 PM CT

Humans mispredict their emotions after decision making

Behavioral research over the past 15 years has confirmed what anyone who has purchased a house or dumped a significant other could tell you: When people make decisions, they anticipate that they may regret their choices. It is important that we maintain this ability, because as the aforementioned house-buyers and spouse-dumpers know, regret can be a terrible feeling.

How accurate are people in their anticipations of regret and of other post-decisional emotions, such as disappointment" It is a topic has been rather neglected by scientists, but new research reported in the recent issue of Psychological Science, a journal of the Association for Psychological Science, aims to fill this gap.

In the first of two experiments, participants took part in a two-person negotiation for money that would allow the scientists to observe negotiation style as well as measure how much regret the participants would feel if their tactics failed. The scientists observed that participants across the board tended to over-predict their post-negotiation regret and disappointment if their transaction was rejected. However, those who negotiated reasonably (i.e., less aggressive or greedy) were less prone to experience regret than the latter, as they had provided sensible offers.

In the second experiment, participants who had just completed a course assignment were asked to predict how they would feel if the grades that they received for their assignments exceeded, matched, or were lower than their expectations. On average, participants received higher than expected grades. However, the scientists observed that participants over-predicted the rejoicing and somewhat under-predicted the regret that they experienced when they received the grades......... Posted by: Beverly      Read more         Source

August 7, 2007, 10:40 PM CT

A New Wrinkle in Thin Film Science

A remarkably simple experiment devised by researchers yields important information about the mechanical properties of thin films--nanoscopically thin layers of material that are deposited onto a metal, ceramic or semiconductor base.

The research results, funded by the National Science Foundation and performed at the University of Massachusetts at Amherst Materials Research Science and Engineering Center, appears in the August 3, 2007, issue of Science.

The findings impact a broad range of scientific disciplines and applications, from cosmetics to coatings, to micro- and nanoelectronics. Understanding the mechanical properties of thin films is essential to their performance and optimization.

Until now, determining the mechanical properties of these thin films was either an expensive and time-consuming endeavor, requiring powerful microscopes to view the films, or researchers examined composite structures and made uncertain assumptions. This new research will give researchers a simple way to access the material properties of most thin films.

"As we delve more into the nanotechnology, it becomes increasingly important to know if the material properties of ultrathin films differ from their properties in the bulk," said Thomas Russell, a program director in the Polymer Science and Engineering Department at the University of Massachusetts in Amherst. "Everyday we see examples where a material's dimensions can change its properties. Aluminum foil is flexible, whereas a bar of aluminum is not. But what happens when a film's thickness approaches molecular dimensions? These experiments give us a simple, inexpensive way to measure mechanical properties of films that are only tens of nanometers thick"......... Posted by: Beverly      Read more         Source

August 3, 2007, 10:33 PM CT

Animated beer smooth to pour

CSIRO fluids researcher Dr Mahesh Prakash says the physics of bubble creation in carbonated drinks like beer is complex.

"As you pour beer into a glass, you see bubbles appearing on what are called nucleation sites, where the glass isn't quite smooth," Dr Prakash says.

"The bubbles expand to a certain size then rise up in streams to the surface, where they bump into each other and form a raft of foam that floats on the top".

Dr Prakash and colleagues have captured the maths describing these processes in software that allows movie makers, film production houses and others to create super-realistic special effects.

The four-year project is being undertaken jointly by CSIRO and South Korea's Electronics and Telecommunications Research Institute, one of the world's largest computer graphics developers for games, with most of the research being done in Melbourne.

Clever maths called smoothed particle hydrodynamics (SPH) helps the software do its job by working smarter not harder. The software uses less computer power and takes less time to get better results than other special effects software it has been benchmarked against.

CSIRO Business and Commercialisation Manager, Andrew Dingjan says CSIRO and ETRI hope this will bring the fluid animation software within reach of smaller film production houses......... Posted by: Beverly      Read more         Source

August 3, 2007, 10:27 PM CT

Sensors Help Africa Tackle Water Shortage

Zambian water authorities are integrating information based on satellite imagery to alleviate water shortages. With inadequate information causing many water-related problems, an ESA project has generated a variety of environmental maps to provide local policy makers with the necessary tools for effective water resource management.

As part of the IWAREMA (Integrated Water Resource management for Zambia) project, funded through ESA's Data User Element, data from ESA's multispectral MERIS sensor aboard Envisat was used to create maps depicting existing water resources, suitable dam locations and land cover. The project is carried out by the Belgium Company GIM (Geographic Information Management) in partnership with the University of Zambia and the Zambian water authorities.

"The results of the IWAREMA project can be used to protect Zambia's ecosystems particularly in the Kafue flats where wildlife, agricultural activities, fisheries and tourism compete for regulated water resources," Jack Nkhoma of Zambia's Department of Water Affairs said.

Having access to these maps allows authorities to determine the expansion of urban areas and loss of forest and agricultural areas as well as calculate the risk of erosion, change in water availability and percentage of surface water, which will allow for early flood warnings......... Posted by: Beverly      Read more         Source

August 3, 2007, 10:04 PM CT

Nano-layer of Ruthenium Stabilizes Magnetic Sensors

A layer of ruthenium just a few atoms thick can be used to fine-tune the sensitivity and enhance the reliability of magnetic sensors, tests at the National Institute of Standards and Technology (NIST) show.* The nonmagnetic metal acts as a buffer between active layers of sensor materials, offering a simple means of customizing field instruments such as compasses, and stabilizing the magnetization in a given direction in devices such as computer hard-disk readers.

In the NIST sensor design, ruthenium modulates interactions between a ferromagnetic film (in which electron “spins” all point in the same direction) and an antiferromagnetic film (in which different layers of electrons point in opposite directions to stabilize the device). In the presence of a magnetic field, the electron spins in the ferromagnetic film rotate, changing the sensor’s resistance and producing a voltage output. The antiferromagnetic film, which feels no force because it has no net magnetization, acts like a very stiff spring that resists the rotation and stabilizes the sensor. The ruthenium layer (see graphic) is added to weaken the spring, effectively making the device more sensitive. This makes it easier to rotate the electron spins, and still pulls them back to their original direction when the field is removed. ........ Posted by: Beverly      Read more         Source

July 30, 2007, 8:09 PM CT

Wider buffers are better

Excess nitrogen caused by fertilizers, animal waste, leaf litter, sewer lines, and highways is responsible for contaminating groundwater. It can also cause human health risks when found in drinking water and oxygen depleted water bodies endangering animals that drink from them. Establishing Riparian buffers is considered a best management practice (BMP) by State and Federal resource agencies for maintaining water quality, and they may be particularly critical in controlling amounts of human produced nitrogen.

Researchers at the U.S. Environmental Protection Agency collected data on the buffers along with nitrogen concentration in streams and groundwater to identify trends between nitrogen removal and buffer width, water flow path and vegetation. They found wide buffers (>50 meters) removed more nitrogen than narrow buffers (0-25 meters). Buffers of different vegetation types were equally effective but herbaceous and forest vegetation were more effective when wider. Removal of nitrogen within the water was efficient, but not related with buffer width; however removal on the water surface was correlation to buffer width. Nitrate nitrogen (sometimes used in fertilizer) did not differ by width, flow path or vegetation type. Results from the study are reported in the July-August 2007 issue of the Journal of Environmental Quality......... Posted by: Beverly      Read more         Source

Wed, 25 Jul 2007 04:08:53 GMT

Argemone munita subsp. rotundata

Argemone munita, or prickly poppy, is divided into four subspecies. Assuming I'm correct in my identification to species (which I may not be), it was trivial to identify this to subspecies rotundata – it is the only subspecies which occurs in Nevada, where this photograph was taken.

Read more about prickly poppy via Calflora.net. Posted by: Daniel Mosquin      Read more     Source

July 23, 2007, 5:36 PM CT

Staying out of jams

What do sand, coal, cereal, ice cubes, marbles, gravel, sugar, pills, and powders have in common" They are all granular materials, members of an unruly family of substances that refuse to completely conform to the laws of behavior for either solids or liquidsmuch to the consternation of theoretical physicists and manufacturers alike. Whether its a huge grain silo, a coal hopper or a pharmaceutical manufacturing plant, being able to predict the behavior of dense granular packings subjected to different external stresses is key to keeping things from jamming up or collapsing.

A Brandeis study in the current on-line issue of Physical Review Letters advances a novel theoretical framework to statistically predict the properties of static, mechanically stable grain packings, analogous to the theory known as equilibrium statistical mechanics that governs molecular matter. The study makes inroads into the fundamental understanding of the properties of granular materials.

Until now, such a predictive theoretical framework has been elusive because of the lack of energy conservation. Physicists employ the principle of conservation of energy to describe the behavior of a collection of atoms or molecules. But, in fact, while grains of sand may be tiny, a collection of them in a dune or pile dissipates energy through heat when shaken, stirred or otherwise perturbed. Atoms and molecules, conversely, do not lose energy when they collide......... Posted by: Beverly      Read more         Source

Mon, 16 Jul 2007 02:59:47 GMT

Why is there so much genetic variation?

One of the surprising discoveries when scientists first began looking at genetic variation was that there was a great deal more than expected by theory. In 1966, Richard Lewontin and Jack Hubby published a paper that revolutionized population genetics. They pioneered the use of protein gel electrophoresis to survey dozens of loci in the fruit fly, Drosophila pseudoobscura, and reported that a large fraction of the loci were polymorphic, and that at the average locus there was about a 15% chance that the individual was heterozygous. These results are surprising because it was expected that natural selection will reduce the amount of genetic variation in populations.

Forty years later evolutionary biologists still don't have many solid explanations for genetic variation in nature. However, a recent report in Nature by Fitzpatrick et al. shows that negative frequency dependent selection can maintain alternative feeding alleles in populations of fruit flies. Fruit fly larvae forage for food in two ways: by "roving" or "sitting". Rover larvae move around more than sitter larvae while feeding and they are also more likely to explore new food patches than sitters.

Fitzpatrick et al. discovered that each type was favored by natural selection when rare.

"If you're a rover surrounded by many sitters, then the sitters are going to use up that patch and you're going to do better by moving out into a new patch," says Marla Sokolowski, the PI on the research team. "So you'll have an advantage because you're not competing with the sitters who stay close to the initial resource. On the other hand, if you're a sitter and you're mostly with rovers, the rovers are going to move out and you'll be left on the patch to feed without competition."

Similar behaviors occur in C. elegans, which tend to clump or browse bacteria solitarily. I unsuccessfully looked for frequency and density dependent selection among these worms, but it is likely my assays weren't sensitive enough. The foraging gene is found in many animals, including honeybees, mice and humans. It is interesting to speculate on the roles that it plays in higher organisms, such as ourselves. Does it play any role in food-related behavioral disorders? Posted by: Dennehy      Read more     Source

July 12, 2007, 10:50 PM CT

Dramatic Comeback Of Male Butterflies

Berkeley -- An international team of scientists has documented a remarkable example of natural selection in a tropical butterfly species that fought back - genetically speaking - against a highly invasive, male-killing bacteria.

Within 10 generations that spanned less than a year, the proportion of males of the Hypolimnas bolina butterfly on the South Pacific island of Savaii jumped from a meager 1 percent of the population to about 39 percent. The scientists considered this a stunning comeback and credited it to the rise of a suppressor gene that holds in check the Wolbachia bacteria, which is passed down from the mother and selectively kills males before they have a chance to hatch.

"To my knowledge, this is the fastest evolutionary change that has ever been observed," said Sylvain Charlat, lead author of the study and a post-doctoral researcher with joint appointments at the University of California, Berkeley, and University College London. "This study shows that when a population experiences very intense selective pressures, such as an extremely skewed sex ratio, evolution can happen very fast".

The researchers' findings are described in the July 13 issue of the journal Science.

Charlat pointed out that, unlike mutations that govern such traits as wing color or antennae length, a genetic change that affects the sex ratio of a population has a very wide impact on the biology of the species......... Posted by: Beverly      Read more         Source