Thursday, April 29, 2010

OCEAN SALINITIES SHOW AN INTENSIFIED WATER CYCLE

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Evidence that the world's water cycle has already intensified is contained in new research to be published in the American Journal of Climate.

The stronger water cycle means arid regions have become drier and high rainfall regions wetter as atmospheric temperature increases.

The study, co-authored by CSIRO scientists Paul Durack and Dr Susan Wijffels, shows the surface ocean beneath rainfall-dominated regions has freshened, whereas ocean regions dominated by evaporation are saltier. The paper also confirms that surface warming of the world’s oceans over the past 50 years has penetrated into the oceans’ interior changing deep-ocean salinity patterns.

"This is further confirmation from the global ocean that the Earth’s water cycle has accelerated," says Mr Durack – a PhD student at the joint CSIRO/University of Tasmania, Quantitative Marine Science program.

"These broad-scale patterns of change are qualitatively consistent with simulations reported by the Intergovernmental Panel on Climate Change (IPCC).

"While such changes in salinity would be expected at the ocean surface (where about 80 per cent of surface water exchange occurs), sub-surface measurements indicate much broader, warming-driven changes are extending into the deep ocean," Mr Durack said.

The study finds a clear link between salinity changes at the surface driven by ocean warming and changes in the ocean subsurface which follow the trajectories along which surface water travels into the ocean interior.

The ocean's average surface temperature has risen around 0.4ºC since 1950. As the near surface atmosphere warms it can evaporate more water from the surface ocean and move it to new regions to release it as rain and snow. Salinity patterns reflect the contrasts between ocean regions where the oceans lose water to the atmosphere and the others where it is re-deposited on the surface as salt-free rainwater.

"Observations of rainfall and evaporation over the oceans in the 20th century are very scarce. These new estimates of ocean salinity changes provide a rigorous benchmark to better validate global climate models and start to narrow the wide uncertainties associated with water cycle changes and oceanic processes both in the past and the future – we can use ocean salinity changes as a rain-gauge," Mr Durack said.

Based on historical records and data provided by the Argo Program's world-wide network of ocean profilers – robotic submersible buoys which record and report ocean salinity levels and temperatures to depths of two kilometres – the research was conducted by CSIRO's Wealth from Oceans Flagship and partially funded by the Australian Climate Change Science Program. Australia’s Integrated Marine Observing System is a significant contributor to the global Argo Program.

(Photo: Alicia Navidad)

The Commonwealth Scientific and Industrial Research Organisation (CSIRO)

NEW MATERIAL IS A BREAKTHROUGH IN MAGNETISM

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Researchers from Imperial College London have created a structure that acts like a single pole of a magnet, a feat that has evaded scientists for decades. The researchers say their new Nature Physics study takes them a step closer to isolating a ’magnetic monopole.’

Magnets have two magnetic poles, north and south. ‘Like’ poles, such as north and north, repel one another and ‘opposite’ poles, such as north and south, attract. Whichever way a magnet is cut, it will always have these two poles.

Scientists have theorised for many years that it must be possible to isolate a ‘magnetic monopole’, either north or south on its own, but until recently researchers have been unable to show this in experiments.

Researchers at Imperial have now enabled tiny nano-sized magnets to behave like magnetic monopoles, by arranging them in a honeycomb structure. In late 2009, various teams of scientists reported they had created monopole-like behaviour in a material called ‘spin ice’. In these materials, monopoles form only at extremely low temperatures of -270 degrees Celsius. The Imperial researchers’ structure contains magnetic monopoles at room temperature.

(Photo: ICL)

Imperial College London

FIRST NEWBORN RECEIVES XENON GAS IN BID TO PREVENT BRAIN INJURY

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In a world first, xenon gas has been successfully delivered to a newborn baby in a bid to prevent brain injury following a lack of oxygen at birth. This pioneering technique was developed by Professor Marianne Thoresen of the University of Bristol and carried out at St Michael’s Hospital, part of University Hospitals Bristol NHS Foundation Trust.

Every year in the UK, more than 1,000 otherwise healthy babies born at full term die or suffer brain injury caused by a lack of oxygen and/or blood supply at birth. This can lead to lifelong problems such as cerebral palsy.

The use of xenon gas to prevent brain injury was developed by Professor Thoresen with Dr John Dingley of Swansea University, in a study funded by Sparks, the children’s medical research charity.

The University of Bristol and St Michael’s Hospital have pioneered new treatments for brain injury in babies since 1998 when Professor Thoresen first started cooling babies after a lack of oxygen and showed that this technique could reduce damage in the newborn brain.

Professor Thoresen’s original laboratory work from 1995 had shown that cooling after lack of oxygen reduced brain injury in animal models. Clinical trials in humans then proved that mild cooling by only a few degrees for 72 hours is a safe and beneficial treatment. However, cooling only partially reduces disability and does not prevent it in all babies. The search thus began for a second treatment that could be added to cooling to further reduce disability.

Professor Marianne Thoresen said: “Xenon is a very rare and chemically inert anaesthetic gas found in tiny quantities in the air that we breathe. In 2002 John Dingley and I realised the potential xenon and cooling might have in combination to further reduce disability. Over the past eight years, we have shown in the laboratory that xenon adds to the protective effect of cooling on the brain; however we faced the challenge of how to successfully deliver this rare and extremely expensive gas to newborn babies.”

Dr Dingley has been developing equipment in Swansea for xenon anaesthesia in adults for over 10 years and has invented a machine to successfully deliver the gas to babies. His machine takes the exhaled gas, removes any waste products from it and re-circulates it to be breathed again without any loss at all to the outside air. Some types of specialist military diving equipment work in this way but it is very unusual to build a system small enough to work reliably in newborn babies.

Dr Dingley said: “A key design feature of this machine is that it is very efficient, using less than 200ml of xenon per hour – less than the volume of a soft drinks can. Xenon is a precious and finite resource and difficult to extract so it can cost up to £30 per litre. As even newborns breathe many litres of air per hour, any xenon based treatment would be impossibly expensive without an economical delivery method.

“Despite these challenges, the lack of side-effects and brain protecting properties of xenon make it uniquely attractive as a potential treatment to apply alongside cooling in these babies. We are very grateful to Sparks, the children’s medical research charity, for supporting us in making this happen.”

Following rigorous Medicines and Healthcare Regulatory Authority approvals and other regulatory challenges, the device is now authorised for clinical trials and will be used on a minimum of 12 babies over the coming months. Successful completion of this feasibility trial is the first required step before larger trials can be done in baby units on a larger scale.

(Photo: Bristol U.)


WEIGHING THE CELL

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Using a sensor that weighs cells with unprecedented precision, MIT and Harvard researchers have for the first time measured the rate at which single cells accumulate mass — a feat that could shed light on how cells control their growth and why those controls fail in cancer cells.

The research team, led by Scott Manalis, MIT associate professor of biological engineering, revealed that individual cells vary greatly in their growth rates, and also found evidence that cells grow exponentially (meaning they grow faster as they become larger).

The new measurement system, reported in the April 11 edition of the journal Nature Methods, is the first technique that can measure cells’ mass as they grow over a period of time (in this case, ranging from five to 30 minutes). Previous methods for measuring cell growth rates have focused on volume or length measurements, and have not yet exhibited the necessary precision for revealing single-cell growth models.

The new method should give researchers a way to unravel the relationship between cell growth and cell division — a relationship that has long been murky, says Marc Kirschner, professor of systems biology at Harvard Medical School. While biologists have a good idea of how the cell division cycle is controlled, “the problem of cell growth — how a cell regulates the amount of material it makes — is not well known at all,” says Kirschner, an author of the Nature Methods paper.

A longstanding question in studies of cell growth is whether growth is linear or exponential. Previous studies have yielded conflicting data.

“Over the twofold size range experienced by most proliferating cells, linear and exponential growth curves differ by less than 10 percent, and so the measurement precision must be much less than this,” says Manalis, a member of MIT’s David H. Koch Institute for Integrative Cancer Research.

The researchers studied four types of cells: two strains of bacteria (E. coli and B. subtilis), a strain of yeast and mammalian lymphoblasts (precursors to white blood cells). They showed that B. subtilis cells appear to grow exponentially, but they did not obtain conclusive evidence for E. coli. That’s because there is so much variation between individual cell growth rates in E. coli, even for cells of similar mass, says Francisco Delgado, a grad student in Manalis’ lab and co-lead author of the paper.

If cells do grow exponentially, it means there must be some kind of mechanism to control that growth, says Kirschner. Otherwise, when cells divide into two slightly different-sized daughter cells, as they often do, the larger cell in each generation would always grow faster than the smaller cell, leading to inconsistent cell sizes. Instead, cells generally even out in size, through a mechanism that biologists don’t yet understand.

The cell-mass sensor, which Manalis first demonstrated in 2007, consists of a fluid-filled microchannel etched in a tiny silicon slab that vibrates inside a vacuum. As cells flow through the channel, one at a time, their mass slightly alters the slab’s vibration frequency. The mass of the cell can be calculated from that change in frequency, with a resolution as low as a femtogram (10-15 grams) which is less than 0.01 percent of the weight of a lymphoblast cell in solution.

Michel Godin, a former postdoctoral associate in Manalis’ lab and co-lead author of the paper, developed a way to trap a cell within the microchannel by precisely coordinating the flow direction. That enables the researchers to repeatedly pass a single cell through the channel every second or so, measuring it each time it moves through.

The new system represents a significant advance over any existing cell measurement technique, says Fred Cross, a Rockefeller University professor who studies the yeast cell cycle. “Since it directly measures biomass (at least net biomass with density greater than water) by the truly remarkable expedient of effectively directly placing a single cell on a scale, it is not troubled by ambiguities and inaccuracies inevitably associated with previous, more indirect measurements,” Cross says.

In their current studies, Manalis and his students are tagging proteins inside the cell with fluorescent molecules that reveal what stage of the cell cycle the cell is in, allowing them to correlate cell size with cell-cycle position and ultimately obtain a growth model for yeast and mammalian cells. They are also working on a way to add chemicals such as nutrients, antibiotics and cancer drugs to the fluid inside the microchannel so their effect on growth rates can be studied.

(Photo: Donna Coveney)

MIT

ONLY KNOWN LIVING POPULATION OF RARE DWARF LEMUR FOUND

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Researchers have discovered the world's only known living population of Sibree's Dwarf Lemur, a rare lemur known only in eastern Madagascar. The discovery of approximately a thousand of these lemurs was made by Mitchell Irwin, a Research Associate at McGill University, and colleagues from the German Primate Centre in Göttingen Germany; the University of Antananarivo in Madagascar; and the University of Massachusetts.

The species was first discovered in Madagascar in 1896, but this tiny, nocturnal dwarf lemur was never studied throughout the 20th century. Following the destruction of its only known rainforest habitat, scientists had no idea whether the species still existed in the wild - or even whether it was a distinct species. The study will be published in the current issue of the journal Molecular Phylogenetics and Evolution.

Irwin first observed dwarf lemurs at Tsinjoarivo, Madagascar, in 2001, shortly after setting up a long-term rainforest research site. "Even then we knew something was unusual about them," Irwin said. "Instead of the rainforest species we expected to see, our lemur resembled the species known from dry western forests, only it was much larger."

In 2006, Irwin began collaborating with Marina Blanco, University of Massachusetts at Amherst who trapped dwarf lemurs at several sites throughout Tsinjoarivo. This work led to the further surprise that two morphologically distinct dwarf lemur species were present, living side-by-side. Further work by geneticist Linn Groeneveld, German Primate Center confirmed the existence of the more common Crossley's dwarf lemur, and the elusive Sibree's dwarf lemur.

The new study showed the mystery lemurs to be very similar to the only known specimen of Sibree's dwarf lemur, now in The Natural History Museum in London, England. Genetic analysis shows the mystery lemurs to be highly distinct from all other known species. In fact, the genetic analyses confirmed that of the four known dwarf lemur species, this is the most genetically unique and probably closely resembles the ancestor that gave rise to the other species.

Irwin is hopeful that this new discovery will lead to increased conservation efforts. "On one hand, you want to get the taxonomy right, just to determine how many dwarf lemur species are out there," said Irwin. But protecting this newly rediscovered species from extinction in a country ravaged by habitat destruction is the next challenge. "Without the recognition provided by this study, this species probably would have gone extinct in the near future. Protecting its only known population and determining how many individuals are left are now top priorities, especially since much of this region's forests have already disappeared."

(Photo: McGill U.)

McGill University

LONG-DISTANCE LARVAE SPEED TO NEW UNDERSEA VENT HOMES

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Working in a rare, "natural seafloor laboratory" of hydrothermal vents that had just been rocked by a volcanic eruption, scientists from the Woods Hole Oceanographic Institution (WHOI) and other institutions have discovered what they believe is an undersea superhighway.

This superhighway carries tiny life forms unprecedented distances to inhabit the post-eruption site.

One such "pioneer species," Ctenopelta porifera, appears to have traveled more than 300 kilometers to settle at the site on the underwater mountain range known as the East Pacific Rise.

"Ctenopelta had never been observed before at the study site, and the nearest known population is 350 km to the north," said Lauren Mullineaux, a senior scientist in WHOI's biology department.

The discovery--in collaboration with scientists at the Lamont-Doherty Earth Observatory (LDEO) and the NOAA Pacific Marine Environmental Laboratory (PMEL)--clashes with the widely accepted assumption that when local adult life is wiped out in a hydrothermal eruption, it is replaced by a pool of tiny creatures from nearby vents.

In this case, however, the larvae that re-settled the post-eruption vent area are noticeably different from the species that were destroyed, according to David Garrison, director of the National Science Foundation (NSF)'s Biological Oceanography Program. In addition, the larvae appear to have traveled great distances to reach their destination.

"That raises the question of how they can possibly disperse so far," said Mullineaux. She added that the findings have implications for the wider distribution of undersea life.

A report on the research by Mullineaux and her colleagues is published in the April 12 issue of the journal Proceedings of the National Academy of Sciences (PNAS).

The discovery of hydrothermal vents on the bottom of the Pacific Ocean in 1977 revolutionized ideas about where and how life could exist.

The seafloor vents gushing warm, mineral-rich fluids and teeming with life raised new questions that researchers have been studying ever since, including: How can so much life thrive at the sunless seafloor? What is the nature of organisms at hydrothermal vents? How do animals migrate to other vent sites?

It was this last question that motivated Mullineaux and her team as they began their study of a vent area on the East Pacific Rise "to gather observations of currents, larvae and juvenile colonists in order to understand what physical processes might facilitate dispersal," Mullineaux said.

One of the group's primary challenges was to determine where the organisms around the vent came from.

As the scientists set out on their mission in 2006, "we got a surprise," said Mullineaux. "A seafloor eruption was detected at our study site, resulting in changes in topography and enormous disturbance to ecological communities. The eruption was, in essence, a natural experiment."

By the time the researchers arrived at the site, they found a scene quite unlike that usually observed at a hydrothermal vent.

Normally, such fissures are teeming with life, supported by the hot chemicals that spew from the vents and provide food through microbial chemosynthesis, a deep-sea version of photosynthesis.

But at this spot on the East Pacific Rise, near 9 degrees North, there was no life.

The eruption had wiped it out.

"Although the vents survived, the animals did not, and virtually all the detectable invertebrate communities were paved over," said Mullineaux. "For us, this was an exciting event. In essence it was a natural clearance experiment that allowed us to explore how the elimination of local source populations affected the supply of larvae and re-colonization."

What the scientists found went against the accepted assumption that most of the organisms needed to re-populate an area come from relatively nearby. But instead, the new larval inhabitants were from a considerable distance away.

"These results show clearly that the species arriving after the eruption are different than those before," says Mullineaux, "with two new pioneer species, Ctenopelta porifera and Lepetodrilus tevnianus, prominent."

The most important finding is that "the processes of the larval stage--as opposed to those of adult organisms--seem to control colonization," Mullineaux said. "We found that a pioneer colonization event by one species, Ctenopelta porifera, radically changed the community structure."

But a question remained: How were these weak-swimming larvae propelled such vast distances to the decimated vent area?

The answer may lie in a recently developed model by Mullineaux's colleagues Dennis McGillicuddy and Jim Ledwell of WHOI, Bill Lavelle of PMEL and Andreas Thurnherr of LDEO, all part of the team for an NSF-funded project called LADDER--LArval Dispersal on the Deep East Pacific Rise.

Seemingly the only way the emigrating larvae could get to their new home from so far away, Mullineaux says, would be to ride ocean-bottom "jets" traveling up to 10 centimeters a second, such as those identified in the work of McGillicuddy and Thurnherr.

Theoretically, however, even these ridge-crest jets might not quite be able to transport the larvae from 350 kilometers within the time frame of their 30-day lifespan, she said. "Either the larvae are using some other transport or they are living longer than we thought," said Mullineaux.

She speculates that large eddies, or whirlpools of water, several hundred kilometers in diameter, may be propelling the migrating larvae even faster--delivering them to their new home while they are still alive. Or perhaps the larvae are able to somehow reduce their metabolism and extend their life.

The findings present an array of fascinating scientific scenarios that warrant further exploration, according to Mullineaux.

They also may open up new ways of looking at the impacts of human activities on the seafloor, such as seafloor mineral mining, which could alter a vent site in a similar way to an eruption.

Such activity could conceivably foster a greater diversity of species at a vent that has just been mined, or it could cause extinction, Mullineaux said. But such scenarios are still highly speculative, she emphasized.

Mullineaux's WHOI co-authors on the paper are Diane Adams, currently at the National Institutes of Health, Susan Mills and Stace Beaulieu.

(Photo: LADDER Project/WHOI Alvin Group)

National Science Foundation

A DIFFERENT KIND OF MINE DISASTER

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The world's largest antimony mine has become the world's largest laboratory for studying the environmental consequences of escaped antimony -- an element whose environmental and biological properties are still largely a mystery.

Scientists from Indiana University Bloomington, the University of Alberta, and the Chinese Academy of Sciences have found the waters around Xikuangshan mine in southwest China contain antimony at levels two to four orders of magnitude higher than normal (0.33 - 11.4 parts per million). The scientists' report will appear in an upcoming edition of Environmental Geochemistry and Health (now online).

"Antimony is an emergent contaminant," said IU Bloomington Ph.D. student Faye Liu, the paper's lead author. "People have not paid enough attention to it."

Used in small quantities, antimony has a wide variety of applications -- from hardening the lead in bullets and improving battery performance to combating malaria.

Little is known about antimony's toxicity, in part because the metalloid element is usually found at low, parts-per-billion concentrations in natural environments. At Xikuangshan, Liu and her colleagues found that aqueous antimony concentrations could be as high 11 parts per million, 1,000 times the antimony levels found in uncontaminated water.

The alarming circumstances at Xikuangshan present an opportunity to understand what happens to antimony, geologically and chemically, when large quantities of it are introduced to the environment. That knowledge will be useful to investigations of antimony contamination near factories and military bases around the world.

The U.S. Environmental Protection Agency and similar regulatory agencies in Europe operate under the assumption that antimony's properties are similar to those of arsenic, another element in antimony's chemical group.

"That will need to change," said IU Bloomington geologist Chen Zhu, Liu's advisor and the project's principal investigator. "We saw that antimony behaves very differently from arsenic -- antimony oxidizes much more quickly than arsenic when exposed."

The vast majority of antimony the scientists isolated at Xikuangshan was of the "V" type, an oxidation state in which the metal has given up five electrons. It is believed V is the least toxic of the three oxidation states of which antimony is capable (I, III and V). It is not known whether antimony-V's relatively diminished toxicity is upended at Xikuangshan by its overwhelming presence.

Land within and around the mining area is used for farming. The drinking water plant for local residents was built in the mining area. Zhu says health problems are common at Xikuangshan, possibly the result of antimony intoxication.

Zhu says he is discussing a possible collaboration with IU School of Medicine toxicologist Jim Klaunig. Researchers would return to Xikuangshan to determine whether the elevated antimony can be tied to acute and chronic health problems among those who live in the vicinity. Another possible study group might be those Chinese who live downstream of Xikuangshan along the Qing River.

As part of their Environmental Geochemistry and Health study, Zhu and scientists from the Chinese Academy of Sciences conducted field work at Xikuangshan in 2007, drawing multiple water samples from 18 different sample sites. Samples were shipped back to Bloomington for atomic fluorescence spectroscopic analysis and to Alberta for inductively coupled plasma mass spectroscopy analysis. The scientists learned antimony-III was rare, beyond detection or present at trace levels. The near totality of antimony in each water sample was antimony-V.

The Xikuangshan antimony mine is the world's largest. Since antimony mining began there more than 200 years ago, mine production has increased steadily to the present day. Today, Xikuangshan produces 60 percent of the world's antimony.

While Zhu was on sabbatical leave in 2008, Faye Liu was advised by IU Bloomington biogeochemist and inaugural Provost's Professor Lisa Pratt. Zhu and Pratt recently began a joint project to learn more about the biogeochemistry of antimony. The scientists' antimony research complements their concurrent NSF-funded research on arsenic.

IU Bloomington geologists Claudia Johnson and Erika Elswick, both participants in the Environmental Geochemistry and Health study, have also taken seawater samples from the Caribbean. Liu is investigating the samples' antimony content.

(Photo: Chen Zhu)

Indiana University Bloomington

MATERIALISTIC PEOPLE ARE LIKED LESS THAN 'EXPERIENTIAL' PEOPLE

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People who pursue happiness through material possessions are liked less by their peers than people who pursue happiness through life experiences, according to a new study led by University of Colorado at Boulder psychology Professor Leaf Van Boven.

Van Boven has spent a decade studying the social costs and benefits of pursuing happiness through the acquisition of life experiences such as traveling and going to concerts versus the purchase of material possessions like fancy cars and jewelry.

"We have found that material possessions don't provide as much enduring happiness as the pursuit of life experiences," Van Boven said.

The "take home" message in his most recent study, which appears in this month's edition of the Personality and Social Psychology Bulletin, is that not only will investing in material possessions make us less happy than investing in life experiences, but that it often makes us less popular among our peers as well.

"The mistake we can sometimes make is believing that pursuing material possessions will gain us status and admiration while also improving our social relationships," Van Boven said. "In fact, it seems to have exactly the opposite effect. This is really problematic because we know that having quality social relationships is one of the best predictors of happiness, health and well-being.

"So for many of us we should rethink these decisions that we might make in terms of pursuing material possessions versus life experiences," he said. "Trying to have a happier life by the acquisition of material possessions is probably not a very wise decision."

CU-Boulder marketing Professor Margaret Campbell and Cornell University Professor Thomas Gilovich were co-authors on the study.

Past studies have found that people who are materialistic tend to have lower quality social relationships. They also have fewer and less satisfying friendships.

In the recent study, Van Boven and his colleagues conducted five experiments with undergraduate students and through a national survey. They sought to find out if people had unfavorable stereotypes of materialistic people and to see if these stereotypes led them to like the materialistic people less than those who pursued life experiences.

In one experiment undergraduates who didn't know each other were randomly paired up and assigned to discuss either a material possession or a life experience they had purchased and were happy with. After talking for 15 or 20 minutes they were then asked about their conversation partners by the researchers.

"What we found was that people who had discussed their material possessions liked their conversation partner less than those who had discussed an experience they had purchased," Van Boven said. "They also were less interested in forming a friendship with them, so there's a real social cost to being associated with material possessions rather than life experiences."

In another experiment using a national survey, the researchers told people about someone who had purchased a material item such as a new shirt or a life experience like a concert ticket. They then asked them a number of questions about that person. They found that simply learning that someone made a material purchase caused them to like him or her less than learning that someone made an experiential purchase.

"We have pretty negative stereotypes of people who are materialistic," Van Boven said. "When we asked people to think of someone who is materialistic and describe their personality traits, selfish and self-centered come up pretty frequently. However, when we asked people to describe someone who is more experiential in nature, things like altruistic, friendly and outgoing come up much more frequently."

So what do you do if you're somebody who really likes to buy lots of material possessions?

"The short answer is you should try to change," Van Boven said. "Not just our research, but a lot of other research has found that people who are materialistic incur many mental health costs and social costs -- they're less happy and more prone to depression."

Van Boven says one thing you can do is choose to be around people who are less interested in material goods.

"It's not a quick fix, but it can be done," he said. "I think what makes it particularly challenging is that it requires some extra effort and mindfulness about the way we make decisions about how to be happy in life."

University of Colorado

TO SLEEP OR NOT TO SLEEP? MATH SOFTWARE TO HELP PLAN ASTRONAUT, SHIFT WORKER SCHEDULES

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Shifting work schedules can wreak havoc on a person's ability to get enough sleep, resulting in poor performance on the job.

Researchers funded by the National Space Biomedical Research Institute (NSBRI) have developed software that uses mathematical models to help astronauts and ground support personnel better adjust to shifting work and sleep schedules. Outside the space program, the software could help people who do shift or night work or who experience jet lag due to travel across time zones.

"The best methods that we know to help people operate at peak performance are first to ensure that they get adequate sleep, and second that their work schedules are designed to be aligned with the natural body clock," said project leader Dr. Elizabeth Klerman, associate team leader for NSBRI's Human Factors and Performance Team.

According to Klerman, a physician in the Division of Sleep Medicine at Brigham and Women’s Hospital in Boston and associate professor at Harvard Medical School, the software has two components. The Circadian Performance Simulation Software (CPSS) uses complex mathematical formulas to predict how an individual will react to specific conditions. CPSS also allows users to interactively design a schedule, such as shifting sleep/wake to a different time, and predicts when they would be expected to perform well or poorly.

The second component, known as Shifter, then "prescribes" the optimal times in the schedule to use light to shift a person’s circadian rhythm in order to improve performance at critical times during the schedule.

"If there is a mission event, such as a spacewalk, scheduled at one or two o'clock in the morning, what can we do to help the astronaut to be alert and functioning well at that time?" Klerman said. "Do we suggest a nap or caffeine? Do we shift their sleep/wake schedule? There are a variety of options that we would like to be able to provide."

Scientists know that an individual's performance and alertness are tightly regulated by several factors related to circadian rhythms and the sleep/wake cycle – length of time awake; the timing, intensity and wavelength of light; the amount of sleep the night before; and the body clock's perception of time. As a result, most people are not able to operate at peak job performance in the late night or early morning hours.

The situation for International Space Station astronauts is complicated by the fact that they often face schedules that are not uniform. A shift in scheduled sleep/wake time, due to an event such as docking, could be as much as eight or nine hours, with the transition taking place over a short period of time. "These dramatic shifts in schedule not only affect the body's ability to know what time it is, but also hinder the body’s ability to give the appropriate signals to a person trying to wake up or go to sleep," Klerman said.

With the basic software program complete, the researchers are now working to individualize the model. They want to determine what personal data are needed in order to provide recommendations for individuals. Klerman said the information needed could be as simple as age, or it could require more complicated data.

The software can easily be adapted for use in many occupations. "This program may be helpful for anyone who has to work the night shift, rotating shifts or extended shifts," Klerman said. "It could also help international travelers effectively deal with jet lag."

Workers outside the space industry that could benefit directly are medical personnel, security or police officers, firefighters, those working in transportation such as long-haul truckers, and power plant operators. Klerman suggested that everyone could benefit indirectly from the modeling. "Our lives, including our safety, are impacted by those people who have jobs requiring shift work or extremely long hours and who may be at increased risk of accidents and errors affecting themselves or others," she said.

Klerman added that lack of sleep can affect more than a person’s alertness and performance. It can impact overall health. Lack of sleep is associated with an increased risk of obesity, pre-diabetic conditions, reduced response to vaccines and changes in cardiovascular functions.

The mathematical modeling effort is one of several projects being conducted by NSBRI’s Human Factors and Performance Team to improve sleep and scheduling of work shifts, as well as determining which specific types of lighting can improve alertness and performance during spaceflight.

(Photo: Elizabeth Klerman, M.D., Ph.D./Brigham and Women’s Hospital)

National Space Biomedical Research Institute

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