Anthropology News, Science News

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

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

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.

  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

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

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

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

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/

The adage that your enemies know your weaknesses best is especially true
in the case of plants and predators that have co-evolved: As the
predators evolve new strategies for attack, plants counter with their
own unique defenses.

Milkweed is the latest example of this response, according to
Cornell research suggesting that plant may be shifting away from
elaborate defenses against specialized caterpillars toward a more
energy-efficient approach. Genetic analysis reveals an evolutionary
trend for milkweed plants away from resisting predators to putting more
effort into repairing themselves faster than caterpillars –
particularly the monarch butterfly caterpillar — can eat them.

"An important question with co-evolution is where does it end?" said
Anurag Agrawal, Cornell associate professor of ecology and evolutionary
biology and lead author of a paper in the current issue of the
Proceedings of the National Academy of Sciences. "One answer is when it
becomes too costly. Some plants seem to have shifted away from
resisting herbivory [plant eating] and have taken that same energy and
used it to repair themselves."

The paper is important because it sheds light on key theories of
co-evolution, claiming that pressure by foraging insects makes plants
diversify as they evolve new defensive strategies and that such
diversification follows trends in one direction or another, said
Agrawal.

Milkweed species have evolved elaborate resistance strategies to
fight off caterpillars that eat their leaves. These include hairs on
their leaves, heart poisons called cardenolides in their tissues and
milky-white toxic latex that pours from the plants’ tubes. A
caterpillar’s bite into a milkweed leaf leads to a flood of latex that
is "like getting a gallon of sticky paint thrown into your face," said
Agrawal.

Some caterpillars, in turn, have adapted by shaving the leaf,
cutting a leaf’s veins in a circle and then eating in the middle where
the latex doesn’t flow. Also, the monarch caterpillar has become immune
to the cardenolides.

Using DNA sequence data to look at relationships between 38 species
of milkweed, Agrawal and colleague Mark Fishbein, a Portland State
University biologist, found evolutionary declines in milkweed’s three
most important resistance traits (hairs, cardenolides and latex) and an
escalation in the plant’s ability to regrow.

Agrawal was surprised, he said, to find that the plant became more
tolerant rather than more diverse in its defenses. The reason, he
speculated, could be because as its predators have become so
specialized, the plant was better off choosing a new defensive tactic
"to tolerate the herbivory damage instead of resisting it." It is
unknown whether such strategies have also evolved in animals trying to
evade parasites.

The findings address questions about plant evolution, biodiversity
and keystone species and may give plant scientists clues about
profitable pest control strategies.

The study was funded by the National Science Foundation.

One of the easiest ways to identify an object is by its color –
perhaps it is because children’s books encourage us to pair certain
objects with their respective colors. Why else would so many of us
automatically assume carrots are orange, grass is green and apples are
red?

In two experiments by Holger Mitterer and Jan Peter
de Ruiter from the Max Planck Institute for Psycholinguistics,
perception of color and color constancy (the ability to see the same
color under varying light conditions) were examined using different
hues of orange and yellow. By using these hues on different objects,
the researchers hoped to show that knowledge of objects can be used to
identify color.

In one experiment, half of the
participants saw traditionally-colored orange objects in their
respective hue, while the other participants saw the same objects in an
ambiguous hue between yellow and orange. The participants that saw the
ambiguous hue on traditionally-colored orange objects later called the
item with that ambiguous hue "orange". Apparently, seeing the ambiguous
hue on a traditionally-colored orange objects led participants to
redefine that hue to be proper "orange".

In the second
experiment, participants saw the same hues, but now on objects that
could be any color (e.g., a car). Some participants were shown objects
that ranged from the ambiguous color from the first experiment to a
strong yellow hue, while others were shown objects in a range of strong
orange hues to the ambiguous color. Just as in the first experiment,
participants then had to identify a sock that had been colored with an
ambiguous hue. This second experiment revealed no differences between
the two groups, showing conclusively that it was only the knowledge of
how objects are naturally colored that made them redefine the colors in
the first experiment.

The results, published in the July issue of Psychological Science,
a journal of the Association for Psychological Science, determined that
the use of top-down processing, such as a carrot signifying the color
orange, is delayed in both color perception and also in other
perceptual domains. If humans used this conceptual knowledge
immediately, it would override perceptual cues and cause
hallucinations.

“Delayed feedback for learning prevents
such illusions, but still utilizes prior probabilities provided by
world knowledge to achieve perceptual constancy,” the researchers
concluded.

Author  Contact: Holger Mitterer Holger.Mitterer@mpi.nl