Anthropology News, Science News - Scicornwall.com

Study suggests human visual system could make powerful computer

Troy, N.Y. – Since the idea of using DNA to create faster, smaller, and more powerful computers originated in 1994, scientists have been scrambling to develop successful ways to use genetic code for computation. Now, new research from a professor at Rensselaer Polytechnic Institute suggests that if we want to carry out artificial computations, all we have to do is literally look around.

Assistant Professor of Cognitive Science Mark Changizi has begun to develop a technique to turn our eyes and visual system into a programmable computer. His findings are reported in the latest issue of the journal Perception.

Harnessing the computing power of our visual system, according to Changizi, requires visually representing a computer program in such a way that when an individual views the representation, the visual system naturally carries out the computation and generates a perception.

Ideally, we would be able to glance at a complex visual stimulus (the software program), and our visual system (the hardware) would automatically and effortlessly generate a perception, which would inform us of the output of the computation, Changizi said.

Changizi has begun successfully applying his approach by developing visual representations of digital circuits. A large and important class of computations used in calculators, computers, phones, and most of today's electronic products, digital circuits are constructed from assemblies of logic gates, and always have an output value of zero or one.

"A digital circuit needs wire in order to transmit signals to different parts of the circuit. The 'wire' in a visual representation of a digital circuit is part of the drawing itself, which can be perceived only in two ways," said Changizi, who created visual stimuli to elicit perceptions of an object tilted toward (an output of one) or away (an output of zero) from the viewer. "An input to a digital circuit is a zero or one. Similarly, an input to a visual version of the circuit is an unambiguous cue to the tilt at that part of the circuit."

Changizi used simple drawings of unambiguous boxes as inputs for his visually represented digital circuits. The positioning and shading of each box indicates which direction the image is tilted.

He also created visual representations of the logic gates NOT, which flips a circuit's state from 0 to 1 or vice versa; OR, which outputs 1 if one or both inputs are 1; and AND, which outputs 1 only if both inputs are 1.

"Visually represented NOT gates flip a box's perceived tilt as you work through a circuit, and OR gates are designed with transparency cues so that the elicited perception is always that the box is tilted toward you, unless overridden," Changizi said. "The AND gate is similarly designed with transparency cues, but contrary to the OR gate, it will always favor the perception that it is tilted away from you."

By perceptually walking through Changizi's visual representation of a digital circuit, from the inputs downward to the output, our visual system will naturally carry out the computation so that the "output" of the circuit is the way we perceive the final box to tilt, and thus a one or zero.

"Not only may our visual system one day give DNA computation a run for its money, but visual circuits have many potential advantages for teaching logic," Changizi said. "People are notoriously poor logical reasoners — someday visual circuits may enable logic-poor individuals to 'see their way' through complex logical formulae."

Although Changizi's visual stimuli are successful at eliciting viewer perception, he says there are still serious difficulties to overcome. The visual logic gates do not always transmit the appropriate perception at the output, and it can be difficult to perceive one's way through these visual circuits, although Changizi argues we may have to train our visual system to work through them, similar to the way we need to be taught to read.

Additionally, building larger circuits will require smaller or more specialized visual circuit components.

"My hope is that other perception and illusion experts will think of novel visual components which serve to mimic some digital circuit component, thereby enriching the powers of visual circuits," Changizi said.

Source

This old healthy house

Obesity linked to newer, less walkable neighborhoods

SALT LAKE CITY – The age of your neighborhood may influence your risk of obesity, according to a new study from the University of Utah.

        The study, to be published in the September issue of the American Journal of Preventive Medicine, linked the body mass index (BMI) of nearly a half million Salt Lake County residents to 2000 Census data. The study found that residents were at less risk of being obese or overweight if they lived in walkable neighborhoods—those that are more densely populated, designed to be more friendly to pedestrians and have a range of destinations for pedestrians.

The study found that neighborhoods built before 1950 tended to offer greater overall walkability as they more often were designed with the pedestrian in mind, while newer neighborhoods often were designed to facilitate car travel.

Demographer Ken Smith, co-author of the study and professor of family and consumer studies at the University of Utah, says that although individuals clearly make personal decisions that influence their weight, neighborhood characteristics also play a potentially important role in affecting residents' risk of obesity.

"It is difficult for individuals to change their behavior," he says, "but we can build environments that promote healthy behavior."

Using height and weight data collected by the Driver License Division of the Utah Department of Public Safety, Smith and colleagues calculated the BMI of 453,927 Salt Lake County residents age 25 to 64, linking it to census-block groups via geographical coordinates. To protect confidentiality, all personal information from the Driver License Division was removed before the data were provided to the researchers. The study was approved by the University of Utah Institutional Review Board.

The study found that a man of average height and weight (6 feet, 200 pounds) weighed 10 pounds less if he lived in a walkable neighborhood versus a less walkable neighborhood. A woman of average size (about 5-foot-5, 149 pounds), weighed six pounds less.

        "The data show that how and where we live can greatly affect our health," says Smith.

According to the study, during 2003-2004 roughly 70 percent of men and 61 percent of women in the U.S. were overweight. The study also notes that by 2030, about half the buildings in the U.S. will have been built since 2000. How this growth occurs will have a significant impact on the environment and on the health of the people living in it, Smith says.

"We have the opportunity, using evidence-based data on community design, to create neighborhoods that encourage less car driving, benefiting residents' health and wallets and shrinking our own carbon footprint," says Smith.

Neighborhoods with higher percentages of pedestrian traffic—something the study found is associated with less obesity among residents—can serve as models for future residential development and redevelopment. "Neighborhoods with higher fractions of residents that walk to work tell us that something beneficial about the neighborhood is promoting health," notes Smith.

"We expect these results mean that residents find walking more attractive and enjoyable where there are other walkers, a variety of destinations easily accessible by foot and pedestrian-friendly street networks. People want to walk when it's pleasant, convenient and when there is a destination."

Taunya Dressler - University of Utah

The kids most likely to go armed

A new analysis of a 2005 survey of American schoolchildren has identified factors that may be used to help improve school safety. The research, published in BioMed Central's open access journal Annals of General Psychiatry, gives detailed information about the carrying of guns, blades and clubs.

13,707 students participated in the study, 6,664 (50.5%) were male and 7,193 (49.5%) were females. Overall, 10.2% of males and 2.6% of females reported carrying a weapon on school property. An estimated 29.8% of males and 19.3% of females had carried weapons elsewhere.

The analysis was carried out by Emmanuel Rudatsikira, from the Loma Linda University, California, and his colleagues. They showed that the variables most associated with the carrying of weapons were being male and being a member of certain self-selected racial groups. Pupils who identified themselves as white were more likely to carry weapons than those who identified themselves as black.

The authors point out that, "We do not believe that there are any inherent genetic differences that determine race and that affect the way that adolescents behave. We take the view that racial categorization has facilitated the distribution of social and economic resources (housing, school districts, wealth, social networks) that may consequently influence adolescent behaviors and perceptions toward violent behavior".

The results were surprising. The authors state that as the poor are likely to live in violent neighbourhoods, they would be more likely to feel unsafe and therefore carry weapons to school, "We would have expected that minorities such as African Americans, being largely disadvantaged in the United States, would be more likely to bear weapons." Rudatsikira suggests some explanations for this apparent discrepancy "If black students felt less threatened at school, it's less likely they'll carry weapons. Alternatively, the schools they attend may be more vigilant in policing weapon carrying as a possible result of high violence and weapon bearing in black neighbourhoods."

Other factors associated with weapon carrying were substance use, depression, having been a victim of theft or property damage at school, having been raped, having been threatened with a weapon or having been involved in a physical fight.

A bee's future as queen or worker may rest with parasitic fly

  Strange things are happening in the lowland tropical forests of Panama and Costa Rica. A tiny parasitic fly is affecting the social behavior of a nocturnal bee, helping to determine which individuals become queens and which become workers.

The finding by researchers from the University of Washington and the Smithsonian Tropical Research Institute is the first documented example of a parasite having a positive affect on the social behavior of its host. This is accomplished by cleptoparasitism – in this case fly larvae stealing food from the developing immature bees. The researchers found that smaller bees that emerge in a nest are dominated by their mothers. These small bees are more likely to stay and act as helping workers, while larger bees tend to depart and start new nests as egg-laying queens. Bees that emerge from cells, or brood chambers, that also house flies are smaller than their nest mates from fly-free cells. The flies may encourage worker behavior in some bees.

"We often think of parasitism in terms of it affecting an animal's fitness, its survival or its ability to reproduce," said Sean O'Donnell, a UW associate professor of psychology and co-author of the paper appearing in the current issue of the Journal of Insect Behavior.  "Here the parasite is not living inside another animal, but is still stealing resources from the host.

"We think these fly parasites are not affecting the lifespan of the bees, and the bees' mothers benefit by having a helper, or worker, stay around to protect the nest, increasing survivability."

O'Donnell and his colleagues studied two closely related tropical social bees, Megalopta genalis and Megalopta ecuadoria, and a family of very small parasitic flies called Chloropidae.

The bees are important pollinators of night-blooming plants and the female bees can nest alone or live in small colonies. A colony is typically made up of two to four individuals – a queen and her offspring.

Behavioral observations showed that non-reproductive foragers and guards are significantly smaller than the queen bee in a nest, although the relative size of individual bees varied from nest to nest. Here's where the flies apparently fit in and are affecting the bees' behavior. The bees nest in hollowed twigs and sticks hanging in the tropical understory and the flies flick their eggs into the entrance to the bee nests. Some of these eggs randomly fall into cells, or chambers, prepared by the bees, each to hold a larva and pollen that the larva eats. The cells are then sealed, so if a cell does contain fly eggs the young flies are competing with the bee larva for a limited amount of food.

"There is a natural size variation in bees and this is based in part on the amount of food available in the cell," said O'Donnell. "A fly or flies in a cell reducing the amount of food could be a potentially important factor. It seems that the more flies in a cell the smaller the bee is. The key here is relative body size compared to nest mates. The larger individuals become queens because they are not dominated."

The researchers were able to culture the bees and flies from individual cells and counted as many as 15 of the tiny flies in a single cell. Some cells did not contain flies.

"This study is a counterintuitive take on parasitic infection. It encourages us to look for complicated ecological relationships between different species. Parasitism may encourage sociality in some situations. Here it is promoting social behavior," O'Donnell said.

Source - University of Washington

Russian explorers reach bed of world's deepest lake in Siberia

IRKUTSK, July 29 (RIA Novosti) - A team of Russian scientists descended to the bottom of Siberia's Lake Baikal in two mini-submarines on Tuesday, setting a new world record for a freshwater dive. (Photo tour with RIA Novosti: Lake Baikal)

News channel Vesti-24 said the submersibles, Mir-1 and Mir-2, reached a depth of 1,680 meters (5,500 feet) in the world's deepest lake, which holds 20% of the planet's fresh water.

The ongoing expedition in what locals call the 'Sacred Sea' was organized by Artur Chilingarov, a Russian lawmaker who led a symbolic dive to the North Pole seabed last August, during which a Russian flag was planted on the seabed.

Chilingarov earlier said the Mir dives were "a logical continuation of lake exploration that was begun 30 years ago with the Pisces apparatus."

Soviet scientists in a Pisces submersible reached a depth of 1,410 meters (4,600 feet) in 1977, and examined the lake's bed with searchlights. The lake has since been the focus of numerous Soviet, Russian and international research expeditions.

Chilingarov said "major technical problems" have to be overcome in deep dives into the lake, due to "difficult weather conditions which dictate their own special conditions in fresh water."

Baikal, whose age scientists estimate at 25 million years, is a UNESCO World Heritage site with hundreds of species of unique fauna and flora.

Crew member Natalia Komarova, the first woman to take part in a Mir mini-sub dive, told reporters that the results of the expedition would have an important impact on environmental legislation. (VIDEO)

"We need to understand how to protect Baikal and use it without harming its unique ecosystem," she said.

She said new safeguards would be needed to protect the lake, given the planned intensive economic and industrial development of East Siberia over the coming years. The lake has been the focus of major environmental scares in recent years, with a last-minute change to an oil pipeline route that was set to pass near Baikal's shores, and environmental regulators' claims against a pulp mill accused of pumping large volumes of toxic waste into the lake.

The research team is based on the lake's Olkhon Island, where the mini-subs were delivered earlier in the day on barges. The crew includes the head of the local administration and the president of investment company Metropol, which has contributed $6 million to the expedition.

The expedition is set to run for two years, during which the scientists will conduct around 160 dives in various areas of the lake. Research will include tectonic information-gathering, and exploration for archeological artifacts. Expedition leaders have denied media reports that they will also be searching for oil and gas.

With thanks to - em.rian.ru

New study finds smoking predicts increased stroke risk for your spouse

Although Second Hand Smoke (SHS) is widely accepted as a risk factor for coronary heart disease, there have been few studies investigating the association of SHS and stroke risk. In a new study, published in the September 2008 issue of the American Journal of Preventive Medicine, researchers report on evidence of increased risk of stroke for spouses of smokers.

For those who never smoked, being married to a current smoker was associated with a 42% increase in risk of stroke compared to being married to a never-smoker. For former smokers, being married to a current smoker was associated with a 72% increase in risk compared to being married to a never-smoker. Being married to a former smoker was not associated with any increase in risk compared to being married to a never-smoker. This suggests that although stroke risk is elevated if your spouse smokes, that risk is eliminated if your spouse stops smoking. For example, never-smokers married to former smokers had nearly the same stroke risk as never-smokers married to never-smokers. Current smokers had significantly elevated stroke rates compared to never-smokers, and spousal smoking status did not affect this risk among current smokers.

The data were drawn from the Health and Retirement Study (HRS), a National Institute on Aging sponsored longitudinal survey of U.S. adults nationwide aged ≥50 years and their spouses. Enrollments occurred in 1992, 1993, 1998 and 2004 and final analyses included 16,225 respondents. Spousal smoking status was assessed at the time of enrollment and participants were followed an average of 9.1 years after enrollment for the incidence of stroke. All models were adjusted for age; race; Hispanic ethnicity; Southern birthstate; parental education; paternal occupation class; years of education; baseline income; baseline wealth; obesity; overweight; alcohol use; and diagnosed hypertension, diabetes or heart disease.

Recent National Health and Nutrition Examination Survey (NHANES) findings for women also suggested that a husband's smoking increased the wife's risk of stroke, but in NHANES this applied only among smoking women and not among nonsmoking women. The current study found that never-smoking women married to currently smoking husbands had an increased stroke risk, compared to never-smoking women married to never-smoking husbands. This apparent discrepancy may arise from sampling differences, where NHANES participants are younger and stroke rates are lower than in HRS. Because nonsmokers have lower overall stroke risks, spousal smoking may increase stroke risk for current smokers at younger ages but emerge as a detectable risk factor for nonsmokers only at older ages.

Writing in the article, M. Maria Glymour, ScD, Harvard School of Public Health, states, "These findings indicate that spousal smoking increases stroke risk among nonsmokers and former smokers. The health benefits of quitting smoking likely extend beyond individual smokers to affect their spouses, potentially multiplying the benefits of smoking cessation."

With thanks Elsevier Health Sciences

Dinosaur Supertree

It has long been debated whether dinosaurs were part of the ‘Terrestrial Revolution’ that occurred some 100 million years ago during the Cretaceous when birds, mammals, flowering plants, insects and reptiles all underwent a rapid expansion.

An international study, led by the University of Bristol, shows that during their last 50 million years of existence, dinosaurs were not expanding as actively as had been previously thought and that the apparent explosion of dinosaur diversity may be largely explained by sampling bias.

The team produced a ‘supertree’ of dinosaurs, showing the most likely pattern of evolution for 440 of the 600 known species of dinosaur. "Supertrees are very large family trees made using sophisticated computer techniques that carefully stitch together several smaller trees which were previously produced by experts on the various subgroups”, explained lead author Graeme Lloyd.

“Our supertree summarises the efforts of two decades of research by hundreds of dinosaur workers from across the globe and allows to look for unusual patterns across the whole of dinosaurs for the first time." It is the most comprehensive picture ever produced of how dinosaurs evolved. The results are published today (23 July) in the Proceedings of the Royal Society B.

Professor Mike Benton from Bristol University said: "It's not complete, but it's the most detailed and comprehensive single evolutionary tree produced for dinosaurs, and indeed for almost any other group.

"Up until now, most studies of the evolution of dinosaurs were not tested numerically against an accurate and comprehensive database. We hope our study will mark the first of a new wave of such thorough, quantitative studies in palaeontology."

The new study uses statistical techniques to distinguish unusually high rates of diversification from normal rates. The results show that all the bursts of diversification happened in the first fifty million years of the evolution of dinosaurs. Later expansions were not distinguishable from normal rates. This suggests dinosaurs did not take advantage of the new food supplies available during the Cretaceous Terrestrial Revolution – such as flowering plants, lizards, snakes, birds and mammals.

The work was done using the High Performance Computing facilities of the National University of Ireland, Maynooth. It was based on a combination of 155 published dinosaur ‘trees’ and took approximately 5,000 hours of calculation time.
The key focus was to see whether dinosaurs had been part of a major phase of evolution on land – the Cretaceous Terrestrial Revolution (between 125–80 million years ago) – when many new groups of plants and animals expanded rapidly. During this time, the flowering plants and social insects arose and became more and more common. Many backboned animals also expanded to take advantage of the new sources of food.

Source

Nanotech: A regulatory blueprint for the next administration

Former EPA official highlights shortcomings of current federal oversight

Washington, DC — Nanotechnology will significantly change virtually every facet of the way we live. The next president has the opportunity to shape these changes and to ensure that nanotechnology's benefits will be maximized and its risks identified and controlled. A new report by former EPA official J. Clarence (Terry) Davies lays out a clear roadmap for the next presidential administration and describes the immediate and longer term steps necessary to deal with the current shortcomings of nanotechnology oversight.

"The future of the technology is in the hands of the incoming administration. The shape of the future will depend significantly on what the new government does," says Davies, whose report, Nanotechnology Oversight: An Agenda for the New Administration, was released today.

In the report Davies calls for the White House and federal agency policymakers to maximize the use of existing laws to improve nanotechnology oversight. Such measures include defining nanomaterials as "new" substances under federal toxics and food laws, thereby enabling the Environmental Protection Agency (EPA) and the Food and Drug Administration (FDA) to consider the novel qualities and effects of nanomaterials. Davies also calls for federal pesticide and workplace safety laws to be used to protect against potential adverse impacts of nanomaterials.

Immediate policy changes, however, need to be followed by longer-term changes to existing oversight laws. For example, two major high-exposure applications of nanotechnology – cosmetics and dietary supplements – are essentially unregulated. The Federal Food, Drug and Cosmetic Act needs to be amended to deal with these applications. Other laws important to nanotechnology, such as the Toxic Substances Control Act and the Consumer Product Safety Act, also need radical revision, Davies says.

Without increased funding and staffing for relevant agencies many of the actions called for in the report will not be possible.

"In order to ensure the safe development of this rapidly advancing technology, which is projected will enable 15 percent of globally manufactured goods worth $2.6 trillion by 2014, there needs to be an increase in nanotechnology risk research monies in the fiscal year 2009 budget to $100 million and in FY 2010 to $150 million," says David Rejeski, the director of the Project on Emerging Nanotechnologies.

The report highlights the importance of creating sensible nanotechnology oversight policies that will help ensure the safe and sustainable application of nanotechnologies to climate change, food security, water purification, health care, and other pressing global problems.

"Potential risks of nanoscale materials have already been identified, and for the world to realize the benefits of this technology, the next administration must act swiftly and carefully," Rejeski says. "This will be a challenge, but one that could have limitless opportunities to improve the world in the 21st century."

The report is available at: www.nanotechproject.org/n/oversight/