The researchers looked at slime moulds - microscopic single-cell organisms or amoebae that are forced to cooperate with one another when food is in short supply. Studying slime moulds at the cellular level provides the scientists with a unique insight into the genes that may also influence human behaviour.

The international team, including biologists from The University of Manchester, found that some amoebae have the ability to use cheating tactics to give them a better chance of survival. The research - published in the journal Nature - not only demonstrates that cheating is a natural phenomenon governed by our genes but that it may be widespread among social creatures.

"Slime mould amoebae feed off bacteria in the soil but when food becomes scarce they aggregate to form a fruiting body of some 100,000 cells," explained Dr Chris Thompson, in Manchester's Faculty of Life Sciences.

"Some cells become the spore, while about one-quarter form a stalk. The stalk cells die - they appear to sacrifice themselves to allow the spore cells to be dispersed on the wind to new feeding grounds."

The team's earlier work had focused on this remarkable level of cooperation in the hope of gaining an insight into why some cells demonstrated such altruistic behaviour. They concluded that the selfless acts were due to the unacceptable cost of non-cooperation - without a stalk, no amoebae would escape to new feeding grounds and all would perish.

But this latest research has uncovered a dark and complex subplot where some cells cheat the system to give themselves a better chance of survival. And this deadly game must constantly evolve as cells find new and better ways of cheating in what is effectively an evolutionary arms race.

"Social behaviour is an unresolved problem in biology - why would anyone be altruistic and give up something for someone else"" said Dr Thompson. "Our findings suggest that there is no single answer able to explain our observations but that a number of factors are at play.

"An analogy can be drawn from people in a sinking boat. If some people cheat by refusing to bail out water they benefit by conserving energy and will last longer as a result. But if not enough people bail water, or those that do become too exhausted, then everyone, including the cheaters, will drown.

"Interestingly, we noted that cheats only cheated in the presence of non-cheaters - when they could get away with not 'bailing water'. When surrounded by other cheaters, they contribute to the group effort again, 'aware' that if no one does, all of them will die."

Scientists from four well-known institutions say the next major disease like HIV/AIDS or SARS could occur in any of a number of developing countries concentrated along the equator. They encourage increased surveillance to prevent the spread of a potential outbreak.

Using global databases and sophisticated computer models to analyze patterns of emerging diseases, the researchers -- from the Consortium for Conservation Medicine (CCM) at Wildlife Trust, N.Y., the Institute of Zoology, London, U.K., Columbia University, N.Y., and the University of Georgia, Athens, Ga. -- are able for the first time to plot, map and predict where the next pandemic might occur.

Funded through a Human and Social Dynamics Exploratory Research award from the National Science Foundation (NSF), Arlington, Va., the research represents a major breakthrough in understanding where and why pandemic diseases emerge and provides a key tool for preventing them in the future.

"This is an important area of research," said Rita Teutonico, advisor for integrative activities in NSF's Directorate for Social, Behavioral and Economic Sciences. "After years of debate, the scientific community is now able to offer a convincing, predictive tool to help policy professionals and resource managers better allocate global resources in the fight against emerging diseases."

By analyzing global patterns in human population density, population changes, latitude, rainfall and wildlife biodiversity in correlation with patterns of emerging diseases, the researchers were able to show for the first time definitive proof that the number of emerging diseases is increasing.

They cite zoonoses -- diseases that originate in animals -- as the primary problem and conclude these are the most current and important threat to humans. The research shows "that the key threat to public health is where human population growth and wildlife diversity clash," said Peter Daszak, executive director of the Consortium for Conservation Medicine at Wildlife Trust.

The scientists analyzed 335 incidents of previous disease emergence and were able to identify the regions where future diseases were most likely to occur. They plotted the results on a global, "Emerging Disease Hotspots" map.

"Our hotspots map shows that the next new important zoonotic disease is likely to originate in the Tropics, a region rich in wildlife species and under increasing pressure from people," Daszak said.

This is the first time researchers are able to provide a scientific prediction of where the next major disease like HIV or SARS could emerge. During the last three decades, researchers have spent billions of research dollars to deal with the seemingly random emergence of dozens of pandemics. None of their efforts to understand patterns of emergence were successful.

This new research, published in the February 21 edition of the leading scientific journal Nature, successfully examined over 50 years of disease emergence patterns using a specially designed computer database to pinpoint regions of the world that need more monitoring.

"This is a seminal moment in how we study emerging diseases," said Professor John Gittleman, dean in the University of Georgia's Odum School of Ecology, who developed the team's approach to analyzing global databases."Our study has shown that bringing ecological sciences and public health together can advance the field in a dramatic way."

But in light of this new information, the researchers note that additional resources need to be properly directed to safeguard public health.

"Most of our resources are focused on the richer countries in the North that can afford surveillance," said Daszak. "This is basically a misallocation of global health funding, and our priority should be to set up 'smart surveillance' measures in the hotspots, most of which are in developing countries."

"If we continue to ignore this important preventative measure, then human populations will continue to be at risk from pandemic diseases," he said.

The news caused excitement at the AIM workshop attended by 25 of the world's leading analytic number theorists. The work is a joint project between Ce Bian and his adviser, Andrew Booker. Booker commented that, "This work was made possible by a combination of theoretical advances and the power of modern computers." During his lecture, Bian reported that it took approximately 10,000 hours of computer time to produce his initial results.

"This breakthrough opens a door to the study of higher degree L-functions," said Dennis Hejhal, Professor of Mathematics at the University of Minnesota and Uppsala University.

"It's a big advance' added Harold Stark of the University of California, San Diego, who, 30 years ago was the first to accurately calculate second degree transcendental L-functions.

"I thought we were years away from doing this. The geometry of what you have to do and the scale of the computation are orders of magnitude harder."

There are two types of L-functions: algebraic and transcendental, and these are classified according to their degree. The Riemann zeta-function is the grand-daddy of all L-functions. It holds the secret to how the prime numbers are distributed, and is a first-degree algebraic L-function.

The Riemann Hypothesis, announced in 1859 and today the most important of all unsolved math problems, is an example of something that should be true for EVERY L-function. Michael Rubinstein from the University of Waterloo, a participant at the workshop, quickly tested and confirmed the Riemann Hypothesis for the first few zeroes of this newly minted L-function.

Rubinstein, along with William Stein of the University of Washington, will direct a new initiative to chart all L-functions; this project has been recommended for funding by the National Science Foundation. "The techniques developed by Bian and Booker open up whole new possibilities for experimenting with these powerful and mysterious functions and are a key step towards making our group project a success." Rubinstein added.

"It's a big step toward our understanding the 'world of L', which is where most of the secrets of number theory are kept." said Brian Conrey, Director of AIM.

Dorian Goldfeld, Professor of Mathematics at Columbia University summarized the excitement, saying "This discovery is analogous to finding planets in remote solar systems. We know they are out there, but the problem is to detect them and determine what they look like. It gives us a glimpse of new worlds."

The study, published in the journal Science, says the first Americans had their roots in southern Siberia and ventured across the Bering land bridge connecting Asia and North America about 22,000 years ago. But they probably did not migrate down into the Americas until 16,000 years ago, when an ice-free corridor in Canada opened.

Genetic evidence points to a founding population of less than 5000 individuals. Archaeological evidence, meanwhile, suggests that the so-called Clovis culture, distinguished by its unique stone tool kit and dating back about 13,000 years ago, may have been relative latecomers to the Americas.

Aimed at reflecting the major scientific issues facing earth science at the start of the 21st century, the questions represent where the field stands, how it arrived at this point, and where it may be headed.

"With all the advancements over the last 20 years, we can now get a better picture of Earth by looking at it from micro- to macro-perspectives, such as discerning individual atoms in minerals or watching continents drift and mountains grow," said Donald J. DePaolo, professor of geochemistry at the University of California at Berkeley and chair of the committee that wrote the report. "To keep the field moving forward, we have to look to the past and ask deeper fundamental questions, about the origins of the Earth and life, the structure and dynamics of planets, and the connections between life and climate, for example."

The report was requested by the U.S. Department of Energy, National Science Foundation, U.S. Geological Survey, and NASA. The committee selected the question topics, without regard to agency-specific issues, and covered a variety of spatial scales -- subatomic to planetary -- and temporal scales -- from the past to the present and beyond.

The committee canvassed the geological community and deliberated at length to arrive at 10 questions. Some of the questions present challenges that scientists may not understand for decades, if ever, while others are more tractable, and significant progress could be made in a matter of years, the report says. The committee did not prioritize the 10 questions -- listed with associated illustrative issues below -- nor did it recommend specific measures for implementing them.

HOW DID EARTH AND OTHER PLANETS FORM?
While scientists generally agree that this solar system's sun and planets came from the same nebular cloud, they do not know enough about how Earth obtained its chemical composition to understand its evolution or why the other planets are different from one other. Although credible models of planet formation now exist, further measurements of solar system bodies and extrasolar objects could offer insight to the origin of Earth and the solar system.

WHAT HAPPENED DURING EARTH'S "DARK AGE" (THE FIRST 500 MILLION YEARS)?
Scientists believe that another planet collided with Earth during the latter stages of its formation, creating debris that became the moon and causing Earth to melt down to its core. This period is critical to understanding planetary evolution, especially how the Earth developed its atmosphere and oceans, but scientists have little information because few rocks from this age are preserved.

HOW DID LIFE BEGIN?
The origin of life is one of the most intriguing, difficult, and enduring questions in science. The only remaining evidence of where, when, and in what form life first appeared springs from geological investigations of rocks and minerals. To help answer the question, scientists are also turning toward Mars, where the sedimentary record of early planetary history predates the oldest Earth rocks, and other star systems with planets.

HOW DOES EARTH'S INTERIOR WORK, AND HOW DOES IT AFFECT THE SURFACE?
Scientists know that the mantle and core are in constant convective motion. Core convection produces Earth's magnetic field, which may influence surface conditions, and mantle convection causes volcanism, seafloor generation, and mountain building. However, scientists can neither precisely describe these motions, nor calculate how they were different in the past, hindering scientific understanding of the past and prediction of Earth's future surface environment.

WHY DOES EARTH HAVE PLATE TECTONICS AND CONTINENTS?
Although plate tectonic theory is well established, scientists wonder why Earth has plate tectonics and how closely it is related to other aspects of Earth, such as the abundance of water and the existence of the continents, oceans, and life. Moreover, scientists still do not know when continents first formed, how they remained preserved for billions of years, or how they are likely to evolve in the future. These are especially important questions as weathering of the continental crust plays a role in regulating Earth's climate.

HOW ARE EARTH PROCESSES CONTROLLED BY MATERIAL PROPERTIES?
Scientists now recognize that macroscale behaviors, such as plate tectonics and mantle convection, arise from the microscale properties of Earth materials, including the smallest details of their atomic structures. Understanding materials at this microscale is essential to comprehending Earth's history and making reasonable predictions about how planetary processes may change in the future.

WHAT CAUSES CLIMATE TO CHANGE -- AND HOW MUCH CAN IT CHANGE?
Earth's surface temperature has remained within a relatively narrow range for most of the last 4 billion years, but how does it stay well-regulated in the long run, even though it can change so abruptly" Study of Earth's climate extremes through history -- when climate was extremely cold or hot or changed quickly -- may lead to improved climate models that could enable scientists to predict the magnitude and consequences of climate change.

HOW HAS LIFE SHAPED EARTH -- AND HOW HAS EARTH SHAPED LIFE?
The exact ways in which geology and biology influence each other are still elusive. Scientists are interested in life's role in oxygenating the atmosphere and reshaping the surface through weathering and erosion. They also seek to understand how geological events caused mass extinctions and influenced the course of evolution.

CAN EARTHQUAKES, VOLCANIC ERUPTIONS, AND THEIR CONSEQUENCES BE PREDICTED?
Progress has been made in estimating the probability of future earthquakes, but scientists may never be able to predict the exact time and place an earthquake will strike. Nevertheless, they continue to decipher how fault ruptures start and stop and how much shaking can be expected near large earthquakes. For volcanic eruptions, geologists are moving toward predictive capabilities, but face the challenge of developing a clear picture of the movement of magma, from its sources in the upper mantle, through Earth's crust, to the surface where it erupts.

HOW DO FLUID FLOW AND TRANSPORT AFFECT THE HUMAN ENVIRONMENT?
Good management of natural resources and the environment requires knowledge of the behavior of fluids, both below ground and at the surface, and scientists ultimately want to produce mathematical models that can predict the performance of these natural systems. Yet, it remains difficult to determine how subsurface fluids are distributed in heterogeneous rock and soil formations, how fast they flow, how effectively they transport dissolved and suspended materials, and how they are affected by chemical and thermal exchange with the host formations.

Do you remember the seventh song that played on your radio on the way to work yesterday? Most of us don't, thanks to a normal forgetting process that is constantly "cleaning house" - culling inconsequential information from our brains. Researchers at the Buck Institute now believe that this normal memory loss is hyper-activated in Alzheimer's disease (AD) and that this effect is key to the profound memory loss associated with the incurable neurodegenerative disorder.

Last year, this same group of researchers found that they could completely prevent Alzheimer's disease in mice genetically engineered with a human Alzheimer's gene-"Mouzheimer's"-by blocking a single site of cleavage of one molecule, called APP for amyloid precursor protein. Normally, this site on APP is attacked by molecular scissors called caspases, but blocking that process prevented the disease. Now they have studied human brain tissue and found that, just as expected, patients suffering from AD clearly show more of this cleavage process than people of the same age who do not have the disease. However, when they extended their studies to much younger people without Alzheimer's disease, they were astonished to find an apparent paradox: these younger people displayed as much as ten times the amount of the same cleavage event as the AD patients. The researchers now believe they know why.

The Buck Institute study implicates a biochemical "switch" associated with that cleavage of APP, causing AD brains to become stuck in the process of breaking memories, and points to AD as a syndrome affecting the plasticity or malleability of the brain. The study, due to be published in the March 7 issue of the Journal of Alzheimer's Disease, provides new insight into a molecular event resulting in decreased brain plasticity, a central feature of AD.

"Young brains operate like Ferraris - shifting between forward and reverse, making and breaking memories with a facility that surpasses that of older brains, which are less plastic," said Dale Bredesen, MD, Buck Institute faculty member and leader of the research group. "We believe that in aging brains, AD occurs when the 'molecular shifting switch' gets stuck in the reverse position, throwing the balance of making and breaking memories seriously off kilter."

In previous research, lead author Veronica Galvan, PhD, prevented this cleavage in mice genetically engineered to develop the amyloid plaques and deposits associated with AD. These surprising mice had normal memories and showed no signs of brain shrinkage or nerve cell damage, despite the fact that their brains were loaded with the sticky A-beta plaques that are otherwise associated with Alzheimer's disease.

"A-beta is produced throughout the brain throughout life; we believe that it is a normal regulator of the synapses, the connections between neurons," said Galvan, who added that AD, like cancer, is a disease in which imbalanced cell signaling plays an important role.

"The fact that many people develop A-beta plaques yet show no symptoms of AD tells us that the downstream signaling of A-beta-not just A-beta itself-is critical," said Bredesen, "and these pathways can be targeted therapeutically. Simply put, we can restore the balance." Continuing research at the Buck Institute focuses on nerve signaling and efforts to "disconnect" the molecular mechanism that throws memory-making in the reverse direction, as well as understanding mechanisms that support brain cell connections that are crucial to the process of memory making.

In a cohort of patients seen by physicians at two offices of the Dent Neurologic Institute, 28 patients were identified as taking both aspirin and ibuprofen (a nonsteroidal anti-inflammatory drug, or NSAID) daily and all were found to have no anti-platelet effect from their daily aspirin.

Thirteen of these patients were being seen because they had a second stroke/TIA while taking aspirin and a NSAID, and were platelet non-responsive to aspirin (aspirin resistant) at the time of that stroke.

The researchers found that when 18 of the 28 patients returned for a second neurological visit after discontinuing NSAID use and were tested again, all had regained their aspirin sensitivity and its ability to prevent blood platelets from aggregating and blocking arteries.

The study is the first to show the clinical consequences of the aspirin/NSAID interaction in patients being treated for prevention of a second stroke, and presents a possible explanation of the mechanism of action.

The Food and Drug Administration currently warns that ibuprofen might make aspirin less effective, but states that the clinical implications of the interaction have not been evaluated.

"This interaction between aspirin and ibuprofen or prescription NSAID's is one of the best-known, but well-kept secrets in stroke medicine," said Francis M. Gengo, Pharm.D., lead researcher on the study.

"It's unfortunate that clinicians and patients often are unaware of this interaction. Whatever number of patients who have had strokes because of the interaction between aspirin and NSAIDs, those strokes were preventable."

Gengo is professor of neurology in the UB School of Medicine and Biomedical Sciences and professor of pharmacy practice in the UB School of Pharmacy and Pharmaceutical Sciences. Results of the study were published in the January issue of the Journal of Clinical Pharmacology.

"We first looked at this issue way back in 1992 in a study conducted in normal volunteers, but it was published as an abstract only," he said. "We never followed through with a manuscript, but another group published an elegant study in the New England Journal of Medicine showing this interaction at least seven years ago.

"When we began to assess this in our stroke patients, a surprisingly high percentage of a group of 653 patients, around 17 percent, were taking aspirin plus Motrin [a brand of ibuprofen].

"The prescription medication Aggrenox, which also is used for secondary stroke prevention and contains aspirin and extended release dipyridamole, is affected the same way as aspirin," Gengo continued. "In preventing strokes, it is statistically a little better than aspirin but more expensive.

"However, one of the most common side effects when you first start taking Aggrenox is headache, so some physicians, pharmacists or physician assistants tell patients to take a Motrin so they don't get a headache. This likely would negate the effects of the aspirin and extended release dipyridamole. Those patients might as well take this expensive drug and flush it down the toilet."

Gengo and colleagues verified with urine testing that all 18 patients, six men and 12 women, were taking their aspirin or aspirin and extended release dipyridamole as directed. Information on the concomitant use of NSAIDS was obtained from patient interviews. Data from the earlier healthy volunteer study showed the magnitude and time course of each drug administered separately, as well as in combination.

The UB study provides important information, Gengo noted, because in most previous studies, measurements were taken only at one point in time, and that time point may have been during the 4-6 hour window when concentrations of NSAIDS were sufficiently high to inhibit aggregation.

"Our data report the entire time course of this interaction," he said. "The results showed that platelets resumed aggregating within 4-6 hours when aspirin and ibuprofen were taken close together, leaving patients with no anti-platelet effect for 18-20 hours a day. Normally, a single dose of aspirin has an effect on platelet aggregation for 72-96 hours," Gengo said.

"When I lecture to pharmacy students, I tell them 'Please, you have a responsibility to the patients you care for. When you counsel a patient taking aspirin/extended release dipyrdamole to lower stroke risk, tell patients they may have some transient headaches, but to avoid ibuprofen. You may have prevented that patient from having another stroke.'"

As the Antarctic waters heat up because of global warming, king crabs are expanding into waters that were previously too chilly for them.

An atomic clock that uses an aluminum atom to apply the logic of computers to the peculiarities of the quantum world now rivals the world's most accurate clock, based on a single mercury atom. Both clocks are at least 10 times more accurate than the current U.S. time standard.

The measurements were made in a yearlong comparison of the two next-generation clocks, both designed and built at the Commerce Department's National Institute of Standards and Technology (NIST). The clocks were compared with record precision, allowing scientists to measure the relative frequencies of the two clocks to 17 digits-the most accurate measurement of this type ever made. The comparison produced the most precise results yet in the worldwide quest to determine whether some of the fundamental constants that describe the universe are changing slightly over time, a hot research question that may alter basic models of the cosmos.

The research is described in the March 6 issue of Science Express* (see sidebar below). The aluminum and mercury clocks are both based on natural vibrations in ions (electrically charged atoms) and would neither gain nor lose one second in over 1 billion years-if they could run for such a long time-compared to about 80 million years for NIST-F1, the U.S. time standard based on neutral cesium atoms.

The mercury clock was first demonstrated in 2000 and is now four times better than its last published evaluation in 2006, thanks to ongoing improvements in the clock design and operation. The mercury clock continues its reign as the world's most accurate for now, by a margin of 20 percent over the aluminum clock, but the designers say both experimental clocks could be improved further.

"The aluminum clock is very accurate because it is insensitive to background magnetic and electric fields, and also to temperature," says Till Rosenband, the NIST physicist who built the clock and is the first author of the new paper. "It has the lowest known sensitivity of any atomic clock to temperature, which is one of the most difficult uncertainties to calibrate."

Both the aluminum clock and the mercury clock are based on ions vibrating at optical frequencies, which are 100,000 times higher than microwave frequencies used in NIST-F1 and other similar time standards around the world. Because optical clocks divide time into smaller units, they can be far more precise than microwave standards. NIST scientists have several other optical atomic clocks in development, including one based on thousands of neutral strontium atoms. The strontium clock recently achieved twice the accuracy of NIST-F1, but still trails the mercury and aluminum clocks.

Highly accurate clocks are used to synchronize telecommunications networks and deep-space communications, and for satellite navigation and positioning. Next-generation clocks may also lead to new types of gravity sensors, which have potential applications in exploration for underground natural resources and fundamental studies of the Earth.

Laboratories around the world are developing optical clocks based on a variety of different designs and atoms; it is not yet clear which design will emerge as the best candidate for the next international standard.

The new paper provides the first published evaluation of the operational quantum logic clock, so-named because it is based on the logical reasoning process used in quantum computers (see sidebar for details). The clock is a spin-off of NIST research on quantum computers, which grew out of earlier atomic clock research. Quantum computers, if they can be built, will be capable of solving certain types of complex problems that are impossible or prohibitively costly or time consuming to solve with today's technologies.

The NIST quantum logic clock uses two different kinds of ions, aluminum and beryllium, confined closely together in an electromagnetic trap and slowed by lasers to nearly "absolute zero" temperatures. Aluminum is a stable source of clock ticks, but its properties cannot be detected easily with lasers. The NIST scientists applied quantum computing methods to share information from the aluminum ion with the beryllium ion, a workhorse of their quantum computing research. The scientists can detect the aluminum clock's ticks by observing light signals from the beryllium ion.

NIST's tandem ion approach is unique among the world's atomic clocks and has a key advantage: "You can pick from a bigger selection of atoms," explains NIST physicist Jim Bergquist, who built the mercury clock. "And aluminum has a lot of good qualities-better than mercury's."

An optical clock can be evaluated precisely only by comparison to another clock of similar accuracy serving as a "ruler." NIST scientists used the quantum logic clock to measure the mercury clock, and vice versa. In addition, based on fluctuations in the frequencies of the two clocks relative to each other over time, NIST scientists were able to search for a possible change over time in a fundamental quantity called the fine-structure constant. This quantity measures the strength of electromagnetic interactions in many areas of physics, from studies of atoms and molecules to astronomy. Some evidence from astronomy has suggested the fine-structure constant may be changing very slowly over billions of years. If such changes are real, scientists would have to dramatically change their theories of the fundamental nature of the universe.

The NIST measurements indicate that the value of the fine-structure constant is not changing by more than 1.6 quadrillionths of 1 percent per year, with an uncertainty of 2.3 quadrillionths of 1 percent per year (a quadrillionth is a millionth of a billionth). The result is small enough to be "consistent with no change," according to the paper. However, it is still possible that the fine-structure constant is changing at a rate smaller than anyone can yet detect. The new NIST limit is approximately 10 times smaller than the best previous measurement of the possible present-day rate of change in the fine-structure constant. The mercury clock is an especially useful tool for such tests because its frequency fluctuations are magnified by any changes in this constant.

Katie Moriarty, a wildlife biology student, was conducting research on another carnivore called the American marten when a remote-controlled camera she set photographed the animal on February 28, 2008. Forest Service scientists who are experts at detecting rare carnivores believe the photographed animal is a wolverine.

The North American wolverine is the largest member of the weasel family. Adult males weigh 26 to 40 pounds, while females are 17 to 26 pounds. It resembles a small bear, with a bushy tail and broad head. Its diet includes carrion, small animals, birds, insects and berries.

U.S. populations are found largely in the Northern Cascades in Washington, and Northern Rockies in Montana and Idaho. The nearest known resident population is about 900 miles north of the Tahoe National Forest in Northern Washington.

Attempts have been made for decades to photograph wolverines in California, according to Bill Zielinski, a Forest Service scientist with the Pacific Southwest Research Station and an expert at detecting wolverines, marten and fisher. He said periodic sightings have occurred, but never scientifically confirmed using detection methods that produce verifiable evidence.

Scientists will now conduct further detection analysis on the Tahoe National Forest using remote-controlled cameras and barbed wire snares that snag hair. They may also use dogs trained to find wolverine scat. Scientists have found dogs to be three and a half times more successful at detecting rare carnivores than remote-controlled cameras in forested areas like the Sierra Nevada Mountains.

Zielinski said hair and scat samples would contain DNA that can be analyzed to determine where the animal originated.

"We have good genetic templates from populations that have been studied elsewhere that can be used to understand the origin of this animal," he said. "But, first we need a DNA sample."

Wolverines have large home ranges that vary greatly depending upon gender, age and food availability. In order to avoid interference with ongoing studies, Forest Service officials are not releasing the exact location where the wolverine was photographed.

The agency's regional forester for California has listed the wolverine as a sensitive species, and the 2004 Sierra Nevada Forest Plan Amendment directs the Forest Service to conduct an analysis to determine if activities within 5 miles of where a wolverine was detected will affect the species.

"This is an exciting research discovery, both for its scientific value, and as a demonstration of our success in forest management." said Tahoe National Forest Supervisor Tom Quinn. "For now, we on the Tahoe National Forest have more questions than answers. We have initiated discussions with researchers about where this sighting occurred and how this could affect management of the National Forest. We are also consulting with wolverine experts and forest managers where wolverine populations occur, and gathering current literature and studies. As we learn more, we will assess which projects and activities, if any, might be affected."

In the late Cretaceous era, about 80 million years ago, global levels were 560 feet (170 meters) higher than today, according to a reconstruction of ocean basins from the time.

The study led by Darrell Gaskin, health economist in the University of Maryland's department of African American Studies, appears in the March 11 issue of Health Affairs. The study of 1841 hospitals in 13 states compares the quality of treatment for blacks, Hispanics and Asians to that of whites over a broad range of services. It found that only a few hospitals provide lower quality care to minorities than to whites.

"The good news," said Gaskin, "is that if you come to the hospital for care, you're probably getting the same quality as everyone else in that hospital."

The study also may help pinpoint where improvements need to be made to reduce the significant health care disparities that are known to exist because of race, ethnicity and income. "Our study confirms that all patients in low performing hospitals are at higher risk for mortality and complications. We need to focus on improving those low performers as opposed to hospitals nationwide," Gaskin said. "Our results also suggest that we need to look more carefully at other areas to find where disparities are originating, such as getting access to the good hospitals in the first place."

Gaskin admits he was surprised at the results of the three-year study. Earlier studies that looked at only a few specific conditions, such as cardiac care, and used general estimating equations, have shown quality differences based on race.

What made this study different, Gaskin said, is that "we compared a broader range of services and directly compared hospital-specific quality indicators for racial and ethnic groups. We examined rates of mortality and complications - whether something bad happened in the hospital because of the care."

Gaskin's group looked at hospitals in 13 states that report patients' race and that collect the specific data the researchers needed to compute quality measures. Forty-four percent of the U.S. population live in these states, with 36 percent of Asians, about 50 percent of Hispanics, 46 percent of African Americans and more than 44 percent of whites residing in the areas studied. The study covered more than 45 percent of urban hospitals and 28 percent of rural hospitals.

"The findings indicate that the systems in place in the hospitals do work to deliver equal quality to patients in that same hospital. It's difficult for one person's bias to make a difference in treatment that would show in mortality rates," Gaskin said.

Gaskin is now working on a study to examine minorities' access to quality medical care, particularly how primary care affects equal access. "We have a tremendous problem with minorities, especially blacks and Asians, getting access to the good hospitals or being referred for care when it could make the most difference. The access problem isn't going to be solved in the hospital. It has to be solved in communities."