The National Science Foundation’s (NSF) Research on Gender in Science and Engineering (GSE) program seeks to broaden the participation of girls and women in science, technology, engineering and mathematics (STEM) education fields by supporting research, the diffusion of research-based innovations, and extension services in education that will lead to a larger and more diverse domestic science and engineering workforce.

Though the program’s name has changed over the years, it has been supporting these objectives since 1993, and its work has led to real changes in the opportunities available for girls and women to participate in the study of science, technology, engineering and math.

“We know a great deal about where the challenges and opportunities are,” says Jolene Kay Jesse, program director for GSE. “There are helpful strategies for teachers and for families to attract girls to science and keep them engaged in it. And, by the way, these strategies are helpful in keeping students of both genders engaged.”

Following are five myths about girls and science.

1. Myth: From the time they start school, most girls are less interested in science than boys are.

Reality: In elementary school about as many girls as boys have positive attitudes toward science. A recent study of fourth graders showed that 66 percent of girls and 68 percent of boys reported liking science. But something else starts happening in elementary school. By second grade, when students (both boys and girls) are asked to draw a scientist, most portray a white male in a lab coat. The drawings generally show an isolated person with a beaker or test tube. Any woman scientist they draw looks severe and not very happy. The persistence of the stereotypes start to turn girls off, and by eighth grade, boys are twice as interested in STEM careers as girls are. The female attrition continues throughout high school, college, and even the work force. Women with STEM higher education degrees are twice as likely to leave a scientific or engineering job as men with comparable STEM degrees.

2. Myth: Classroom interventions that work to increase girls’ interest in STEM run the risk of turning off the boys.

Reality: Actually, educators have found that interventions that work to increase girls’ interest in STEM also increase such interest among the boys in the classroom. When girls are shown images of women scientists and given a greater sense of possibility about the person they could become, the boys get the message too–”I can do this!”

There are more opportunities than ever for girls and boys to explore science together. One resource: the discoveries, games and hands-on experiments available at http://pbskids.org/dragonflytv/.

3. Myth: Science and math teachers are no longer biased toward their male students.

Reality: In fact, biases are persistent, and teachers often interact more with boys than with girls in science and math. A teacher will often help a boy do an experiment by explaining how to do it, while when a girl asks for assistance the teacher will often simply do the experiment, leaving the girl to watch rather than do. Research shows that when teachers are deliberate about taking steps to involve the female students, everyone winds up benefiting. This may mean making sure everyone in the class is called on over the course of a particular lesson, or asking a question and waiting 10 seconds before calling on anyone. Good math and science teachers also recognize that when instruction is inquiry-based and hands-on, and students engage in problem solving as cooperative teams, both boys and girls are motivated to pursue STEM activities, education and careers.

Resisting stereotypes and furthering opportunities, Girls Creating Games was created as an after-school and summer program designed to support the interest of middle school girls in computers and information technology. Its goal is to increase the number of women and girls in the IT workforce. A sample of the girls’ creations is accessible at http://programservices.etr.org/gcgweb/.

4. Myth: When girls just aren’t interested in science, parents can’t do much to motivate them.

Reality: Parents’ support (as well as that of teachers) has been shown to be crucial to a girl’s interest in science, technology, engineering and math. Making girls aware of the range of science and engineering careers available and their relevance to society works to attract more women (as well as men) to STEM careers. Parents and teachers are also in a position to tell young people what they need to do (in terms of coursework and grades) to put themselves on a path to a STEM career.

Best known as the first American woman to travel in space, Sally Ride is also a physicist, educator, and author. She is the founder of Sally Ride Science, a science content company dedicated to supporting girls’ and boys’ interests in science, math and technology. She offers a guide for parents, “Science Can Take Her Places” at http://www.sallyridescience.com/.

5. Myth: At the college level, changing the STEM curriculum runs the risk of watering down important “sink or swim” coursework.

Reality: The mentality of needing to “weed out” weaker students in college majors–especially in the more quantitative disciplines–disproportionately weeds out women. This is not necessarily because women are failing. Rather, women often perceive “Bs” as inadequate grades and drop out, while men with “Cs” will persist with the class. Effective mentoring and “bridge programs” that prepare students for challenging coursework can counteract this. Changing the curriculum often leads to better recruitment and retention of both women and men in STEM classrooms and majors. For example, having students work in pairs on programming in entry-level computer science and engineering (CSE) courses leads to greater retention of both men and women in CSE majors. In addition, given that many students (including men) have difficulty with spatial visualization and learning, coursework in this area has helped retain both women and men in engineering schools.

One of the most effective interventions to help young women choose and sustain a STEM educational path and subsequent STEM career is mentoring. MentorNet, a virtual e-mentoring network and community was established in 1997. Since then, it has expanded to offer award-winning, research-based, technology-leveraged mentoring programs that pair young people with professionals working in STEM careers in industry, government and higher education. Structured e-mail based mentoring relationships are sustained over a period of time with both one-on-one encouragement and advice, and online topic-based discussion groups. A resume database also assists job-seekers. MentorNet is accessible through http://www.mentornet.net.

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Two new publications funded by NSF offer some excellent resources. New Formulas for America’s Workforce 2: Girls in Science and Engineering is the second volume in a series presenting research about the family, school and social structures that create obstacles or provide opportunities to attract girls and women to the STEM disciplines. It also presents the results of interventions that have succeeded in overcoming the obstacles and enhancing the opportunities to bring a new population to the sciences. New Tools for America’s Workforce is a catalog of available resources for educators and others. The publications are accessible at http://www.nsf.gov/ehr/hrd/Newformulas/newformulas.jsp. On-line resources included in the New Tools publication are included with each of the myths discussed here.

In spite of many obstacles, women have made significant contributions to the advancement of science throughout history–from the empress of China who used her scientific abilities to invent silk over 5000 years ago, to the Hollywood glamour queen who patented a missile guidance system that keeps cell phones working today. Hear some of these women’s stories at http://www.womeninscience.org/then.htm.

Source : NSF

Mice whose brains had atrophied like those of Alzheimer’s disease patients regained long-term memories and the ability to learn after living in an enriched environment, researchers at MIT’s Picower Institute for Learning and Memory report in the April 29 advance online edition of Nature. The same results also were achieved with a new experimental class of drugs.

Li-Huei Tsai, Picower Professor of Neuroscience in the Department of Brain and Cognitive Sciences, and colleagues found that environmental enrichment–for laboratory mice, being exposed to stimuli that enhance their physical and psychological well-being–induced the animals’ brain cells to start to sprout new connections.

“This is exciting because our results show that learning ability can be improved and ‘lost’ long-term memories can be recovered even after a significant number of neurons have already been lost in the brain,” said Tsai, who is also a Howard Hughes Medical Institute investigator. “This hints at the possibility that cognitive function can be improved even in advanced stages of dementia.”

What’s more, the researchers’ results help explain why even severely afflicted patients are occasionally lucid.

Master regulators

Tsai’s team was also able to mimic the effect of living in an enriched environment by treating the Alzheimer’s-like mice with histone deacetylase (HDAC) inhibitors. HDACs are a family of 11 enzymes that seem to act as master regulators of gene expression. Drugs that inhibit HDACs are in experimental stages and are not available by prescription for use for Alzheimer’s.

Proteins called histones act as spools around which DNA winds, forming a structure in the cell nucleus known as chromatin. Histones are modified in various ways, including through a process called acetylation, which in turn modifies chromatin shape and structure. (Inhibiting deacetylation with HDAC inhibitors leads to increased acetylation.)

Certain HDAC inhibitors open up chromatin. This allows transcription and expression of genes in what had been a too tightly packaged chromatin structure in which certain genes do not get transcribed.

There has been exponential growth in HDAC research over the past decade. HDAC inhibitors are currently being tested in preclinical studies to treat Huntington’s disease patients. Some HDAC inhibitors are on the market to treat certain forms of cancer. They may help chemotherapy drugs better reach their targets by opening up chromatin and exposing DNA. “To our knowledge, HDACs have not been used to treat Alzheimer’s disease or dementia,” Tsai said. “Future research should address whether HDAC inhibitors will be effective for treating neurodegenerative diseases.”

A better model

Brain atrophy occurs during normal aging and is an early feature of neurodegenerative diseases that affect learning and memory. Until recently, there were no effective animal models for these diseases, limiting researchers’ ability to explore strategies for recovering learning and memory after substantial brain damage had already taken place.

Tsai’s laboratory developed a transgenic mouse in which expression of p25, a protein implicated in various neurodegenerative diseases, can be switched on or off with a change in diet. Mice that expressed the p25 protein had significant loss of brain cells and acted as though they did not remember tasks they had previously learned.

“It’s not clear if memories were simply lost or became inaccessible due to synaptic and neuronal loss,” wrote Tsai. “In the latter case, it might be possible to reestablish the access to such memories if sufficient refinement of the neuronal network can be achieved by the remaining neurons.”

In 2003, a man who was barely conscious for nearly 20 years regained speech and movement at a Mountain View, Ark., rehabilitation center. Last year, doctors said the man’s brain spontaneously rewired itself by growing tiny new nerve connections to replace the ones cut in a car crash. Tsai said the case provides evidence that reestablishment of a neural network may allow recovery of long-term memories in humans as well as rodents.

Using the transgenic mice, Tsai and Picower research affiliates Andre Fischer, Farahnaz Sananbenesi and Xinyu Wang and technical assistant Matthew Dobbin set out to see if they could boost the plasticity–the ability to change–and the function of the animals’ remaining neurons.

Enriching environment

Environmentally enriched (EE) mice have shelves, perches, nesting material, tunnels and other objects in their habitats and are allowed to touch, see, hear or smell other mice. The mice may get opportunities to exercise or learn tasks. Neuroscientists use EE to increase synaptic function in rodents, but no one is sure how or why it works.

In the Nature study, groups of genetically engineered mice were trained for four weeks before neuronal deficits were induced by turning on p25.

Despite the substantial loss of brain cells in the mice, the researchers found that environmental enrichment or elevated histone acetylation resulting from treatment with HDAC inhibitors helped the mice recall maze tasks and other behaviors they had learned weeks before.

The fact that long-term memories can be recovered by environmental enrichment or elevated histone acetylation supports the idea that apparent memory “loss” is really a reflection of inaccessible memories, Tsai said. “These findings are in line with a phenomenon known as ‘fluctuating memories,’ in which demented patients experience temporary periods of apparent clarity.”

Tsai said, “We really hope that our results will lead to a suitable therapeutic approach to treat dementia. However, the immediate next steps are to determine which HDACs regulate distinct forms of synaptic plasticity, learning and memory.”

This work is supported by the National Institutes of Health.

Source: MIT

Oxford scientists have for the first time revealed a link between a gene and the activity of human stem cells, giving hope that stem cell transplant success for blood cancer patients may be significantly improved.

A team at the MRC www.mrc.ac.uk Molecular Haematology Unit at Oxford Universityhas found that a gene called ‘Nephroblastoma Overexpressed’ (known as Nov) plays a key role in regulating how much blood is produced from stem cells. Stem cells are vital for normal blood production and are used in transplants in patients with leukaemia and other blood cancers. The findings, published in Science www.sciencemag.org, raise the possibility of using the Nov gene to amplify the number of blood cells available. The work is funded by Leukaemia Research. www.lrf.org.uk

Dr Rajeev Gupta, one of the authors, said: ‘The Nov gene makes a type of protein similar to a hormone. Switching off the gene reduces stem cell activity and the production of blood cells falls. Conversely, when we added Nov protein to stem cells we increased the production of blood cells. This implies that the gene plays a key role in the regulation of blood production from stem cells.’

Professor Tariq Enver, who leads the team at the MRC Molecular Haematology Unit at Oxford’s Weatherall Institute of Molecular Medicine, said: ‘Of course, genes never work alone, and the next step of our work will focus on identifying the genetic pathway through which Nov works – or in other words, finding out who Nov’s friends are. Once these interactions have been established and we know whether Nov is the best gene to work with, we will be another step closer to devising better therapies for leukaemia patients.

‘It is hoped that the discovery may in the future lead to Nov or a related gene playing a clinical role in stem cell transplants, particularly in the context of cord blood. Cord blood donations contain sufficient numbers of stem cells to treat children, but single donations are generally not enough for use in adults. We are actively pursuing whether Nov can amplify stem cells in cord blood. If so, cord blood could potentially be used more widely for the treatment of adult patients.’

Dr Gupta added: ‘Nov and related genes certainly show great potential to play a role in future improvements for cancer patients treated with stem cell-based therapies, such as bone marrow transplants. We are working to transfer our laboratory work to the bedside.’

Source: University of Oxford

A major study sheds new light on the role of carbon dioxide once it’s transported to the oceans’ depths. The research indicates that instead of sinking, carbon dioxide is often consumed by animals and bacteria and recycled in the “twilight zone,” a dimly lit area 100 to 1,000 meters below the surface. Because the carbon often never reaches the deep ocean, where it can be stored and prevented from re-entering the atmosphere as a green-house gas, the oceans may have little impact on changes in the atmosphere or climate.

The research is the result of two international expeditions to the Pacific Ocean, and is published in the April 27, 2007, issue of Science.

“These results are particularly important to our efforts today to improve the predictive capacity of numerical models that relate ocean carbon to global climate change on different time scales,” said Don Rice, director of NSF’s chemical oceanography program.

It also adds a new wrinkle to proposals to mitigate climate change by fertilizing the oceans with iron–to promote blooms of photosynthetic marine plants and transfer more carbon dioxide from the air to the deep ocean.

“The twilight zone is a critical link between the surface and the deep ocean,” said Ken Buesseler, a biogeochemist at Woods Hole Oceanographic Institution and lead author of the new study, which is co-authored by 17 other scientists. “We’re interested in what happens in the twilight zone, what sinks into it and what actually sinks out of it. Unless the carbon goes all the way down into the deep ocean and is stored there, the oceans will have little impact on climate change.”

Buesseler was the leader of a project funded by the National Science Foundation (NSF) called VERTIGO (Vertical Transport In the Global Ocean).

The twilight zone acts as a gate that allows more sinking particles through in some regions and fewer in others, complicating scientists’ ability to predict the ocean’s role in offsetting the impacts of greenhouse gases.

Using new technology, the researchers found that only 20 percent of the total carbon in the ocean surface made it through the twilight zone off Hawaii, while 50 percent did in the northwest Pacific near Japan.

These sinking particles, often called “marine snow,” supply food to organisms deeper down, including bacteria that decompose the particles. In the process, carbon is converted back into dissolved organic and inorganic forms that are re-circulated and reused in the twilight zone and that can make their way to the surface and back into the atmosphere.

The problem, say scientists, is that particles sink slowly, perhaps 10 to a few hundred meters per day, but they are swept sideways by ocean currents traveling many thousands of meters per day. To collect sinking particles, oceanographers use cones or tubes that hang beneath buoys or float up from sea floor. That, Buesseler said, “is like putting out a rain gauge in a hurricane.”

While many studies have investigated the surface of the ocean, little research has been conducted on the carbon cycle below. The VERTIGO team examined a variety of processes to open a new window into the difficult-to-explore twilight zone. They successfully used a wide array of new tools, including an experimental device that overcame a longstanding problem of how to collect marine snow falling into the twilight zone.

Other scientists involved in VERTIGO are David Karl of the University of Hawaii; Makio Honda of the Japan Agency for Marine-Earth Science and Technology; Deborah Steinberg of the Virginia Institute of Marine Sciences; Mary Silver of the University of California at Santa Cruz; David Siegel of the University of California at Santa Barbara; James Bishop of the University of California at Berkeley; Thomas Trull of the University of Tasmania, Australia; Philip Boyd of the University of Dunedin, New Zealand; and Frank Dehairs of Free University of Brussels, Belgium.

More than 40 biologists, chemists, physical oceanographers, and engineers from 14 institutions and seven countries participated in the two VERTIGO oceanographic research cruises in 2004 and 2005 to investigate how marine plants die and sink, or are eaten by animals and converted into sinking fecal pellets.

Source: NSF

Before fish began to invade land, about 365 million years ago, they had some big problems to solve. They needed to come up with new ways to move, breathe, and eat.

Take the latter, for example. Fish usually pucker up and suck prey into their mouths. But air is 900 times less dense than water, so land-livers must bite into their food to get a meal. Researchers at Harvard University have just completed a study that gives a clear picture of how that change was made.

“Aquatic creatures developed the tools they needed to feed on land before they completely left water,” notes Molly Markey, a lecturer on earth and planetary sciences. “Our research suggests that these first tetrapods, four-footed animals, bit on prey in shallow water or on land. Although they may have occasionally captured a meal by suction.”

To become biters, the invaders had to change their teeth and skulls, and learn to walk. Along with Charles Marshall, a professor of biology and of geology at Harvard’s Museum of Comparative Zoology, Markey compared the boney remains of a 365-million-year-old fish named Eusthenopteron, two ancient tetrapods called Acanthostega and Phonerpeton, and a modern fish. The salamanderlike Acanthostega spent much of its life in the water, Phonerpeton lived on land. Both Acanthostega and Eusthenopteron possessed lungs and gills, so they could breathe air or water, like today’s lungfishes. All three ancients boasted pointed teeth, indicating that they were meat-eating predators.

Studies done by Jenny Clark at Cambridge University in England show that Acanthostega had short legs that stuck out to its sides, ending in what look like webbed toes. Such limbs would not be very supportive, so it’s likely that the old tetrapod slithered or scooted, rather than walked, when it ventured on land.

Slithering and chewing

One big question is why Acanthrostega and its relatives left their aquatic domain in the first place. Were they trying to get away from bigger predators, or were they looking for new prey to feed on? “It’s likely that both reasons are true,” Markey says.

Markey and Marshall compared models of the ancient tetrapods and Eusthenopteron, the fish that stayed at home. They published their findings in the April 16 online edition of the Proceedings of the National Academy of Sciences.

The comparison found that the key to evolving from sucking to biting lay in the tops of the animals’ skulls. These boney skull roofs, rather than being solid, were made up of lots of different pieces. Markey compares them to pieces of a jigsaw puzzle. “Imagine that skull bones are puzzle pieces,” she explains. “Places where they touch each other are known as sutures, and the bones can move around them a bit. The sutures get wider or narrower depending on motions such as chewing.”

By analyzing sutures in the skulls of the ancient tetrapods and fish, then comparing them with those in a living fish, the researchers could determine how the skull roof deformed under the compression and tension of eating. Such analyses led to the conclusion that Eusthenopteron was a sucker and the awkward-moving Acanthostega was a biter — perhaps the first one in the animal kingdom.

Think of that next time you suck in strands of spaghetti or chew on a piece of chicken.

Source: Harvard University

A protein acting as a long-distance signal from leaf to shoot-tip tells plants when to flower, says new research published in Science Express on Thursday 19 April 2007.

The study reveals the likely mechanism by which the Arabidopsis plant flowers in response to changes in day length. Earlier research had shown that plants’ leaves perceived seasonal changes in day length, which triggers a long-distance signal to travel through the plant’s vascular system from the leaf to the shoot apex, where flowering is induced. However, the identity of the long-distance signal remained unclear.

This new research, carried out by scientists at Imperial College London and the Max Planck Institute for Plant Breeding Research in Cologne, has led to the proposal that this signal is a protein known as Flowering Locus T Protein (FT protein), which is produced in leaves by the Flowering Locus T gene (FT gene). It travels through the plant’s vascular system to the shoot apex, where it activates other genes, causing the plant to flower. The research team were able to track the progress of the protein through the plant by tagging it with a green fluorescent protein originally isolated from jellyfish, allowing it to be detected in living tissues using highly sensitive microscope systems.

The team then grafted two plants together, only one of which contained the gene for the fluorescent version of FT. This allowed them to show conclusively that FT protein moved from where it was produced in the leaves of one plant, across into the other plant.

The FT protein is produced when the FT gene is switched on by another gene known as CONSTANS. This is a key gene expressed in leaves which reacts to changes in day length.

Dr Colin Turnbull from Imperial College London’s Division of Biology, who carried out the research, said: “This could be a really important breakthrough in plant science. Since the 1930s when it first became clear that something was communicating the perception of changes in day length in leaves to the shoot apex, and causing flowering, scientists have been trying to work out exactly how this mechanism works.

“Over the past couple of years several labs made exciting discoveries all pointing to the FT gene being central to controlling flowering time. Now that we have been able to track FT protein moving from its source in leaves to its destination in the shoot tip, we have a plausible explanation for how plants respond to day length. Parallel work in Japan shows very similar mechanisms operating in rice, so there is immediate potential to translate research into practical benefits for food crops. The ability to control flowering is of enormous commercial significance across food and non-food species, for example extending production seasons or designing plants better adapted to changing climate.”

Source: Imperial College London

Scientists using one of the nation’s newest and most capable research aircraft are launching a far-reaching field project this month to study plumes of airborne dust and pollutants that originate in Asia and journey to North America.

The plumes are among the largest such events on Earth, so great in scope that scientists believe they might affect clouds and weather across thousands of miles while interacting with the Sun’s radiation and playing a role in global climate.

Known as PACDEX (Pacific Dust Experiment), the project will be led by scientists at the National Center for Atmospheric Research (NCAR) and the Scripps Institution of Oceanography. NCAR’s main sponsor, the National Science Foundation (NSF), will provide most of the funding. The first mission will be launched in late April, depending on weather patterns in Asia. It will continue for two months.

To study the changes in the plumes as they move through the atmosphere from Japan to the western United States, the PACDEX team will deploy the NSF HIAPER, a modified Gulfstream-V aircraft, which is operated and maintained by NCAR. This newly configured plane has a range of about 6,000 miles and can cruise from just a few hundred feet above Earth’s surface to over 50,000 feet. These features enable scientists to study the plumes across thousands of miles and at different levels of the atmosphere.

“Aerosol pollutants, such as those to be studied in PACDEX, account for the largest uncertainties in climate forcing,” said Jay Fein, program director in NSF’s Division of Atmospheric Sciences, which funded the experiment. “PACDEX is addressing this challenging and societally relevant science question.”

While many particles in the plumes, such as sulfates, cool the planet by blocking solar radiation from reaching Earth, some particles such as black carbon absorb sunlight as well and therefore may amplify the effects of global warming. PACDEX will help scientists refine computer models of greenhouse gas emissions and improve forecasts of future climate change, both for the entire globe and for specific regions that are especially affected by dust and pollutants.

“PACDEX will open a window into what happens to the atmosphere as these massive plumes cross the Pacific Ocean and affect clouds, precipitation, and the amount of sunlight that reaches Earth,” explains NCAR scientist Jeff Stith, a principal investigator on the project. “We want to determine how the various particles of dust and pollutants influence clouds and climate, and how far downwind those effects occur.”

“PACDEX comes at a crucial time in our efforts to understand the regional impacts of global warming,” says V. Ramanathan, a PACDEX principal investigator based at the Scripps Institution of Oceanography. “It will also help us help us examine how the dust and soot modifies storm tracks and cloud systems across the Pacific, which influence North American weather patterns in major ways. By focusing on these plumes, PACDEX will shed light on one of the major environmental issues of this decade.”

As Asia’s economies boom, scientists are increasingly turning their attention to the plumes, which pack a combination of industrial emissions (such as soot, smog, and trace metals) and dust from storms in regions such as Central Asia’s Gobi Desert.

The plumes can alter global temperatures by interacting with large-scale, mid-latitude cloud systems over the Pacific that reflect enormous amounts of sunlight and help regulate global climate.

The plumes also may affect regional precipitation patterns because water vapor molecules adhere to microscopic particles of dust and pollutants to form water droplets or ice particles that eventually grow and fall out of the clouds as rain or snow.

In addition, the dust and pollutants reduce the amount of light reaching Earth, contributing to a phenomenon known as global dimming that can affect both temperatures and precipitation.

The Gulfstream-V will carry an array of instruments that will enable scientists to both measure clouds and bring dust, pollutants, and cloud particles into the aircraft for study. Scientists will capture ice particles from clouds, evaporate them, study the residue, and then try to recreate the particle in a special moistened chamber to mimic the temperature and moisture conditions that enabled the original ice particle to form.

The international research team will include scientists from U.S. and Asian organizations.

U.S. organizations include NCAR, Scripps, NASA, NOAA, Arizona State University, Colorado State University, Naval Research Laboratory, Oregon State University, University of Alaska, University of Colorado, and the University of Iowa.

Asian organizations include the Japanese National Institute for Environmental Studies, Lanzhou University and Peking University in China, and Seoul National University in Korea.

Source: NSF

In the first nationally representative study to examine the relationship between survey measures of household firearm ownership and state-level rates of suicide in the United States, researchers at the Harvard School of Public Health (HSPH) found that suicide rates among children, women, and men of all ages are higher in states where more households have guns. The study appears in the April 2007 issue of The Journal of Trauma.

“We found that where there are more guns, there are more suicides,” said Matthew Miller, assistant professor of health policy and management at HSPH and lead author of the study.

Suicide ranks as one of the 15 leading causes of death in the United States; among persons under 45 years old, it is one of the top three causes of death. In 2004, more than half of the 32,439 Americans who committed suicide used a firearm.

Miller and his colleagues Steven Lippmann, David Hemenway, and Deborah Azrael used survey data to estimate rates of household firearm ownership in each of the 50 states and examined whether rates of suicide were related to rates of household gun ownership. They controlled for measures of poverty, urbanization, unemployment, drug and alcohol dependence and abuse, and mental illness. The researchers found that states with higher rates of household firearm ownership had significantly higher rates of suicide by children, women, and men. In the 15 states with the highest levels of household gun ownership, twice as many people committed suicide compared with the six states with the lowest levels, even though the population in both groups was about the same.

The association between firearm ownership and suicide was due to higher gun-related suicides; nongun-related suicide rates were not significantly associated with rates of firearm ownership. Also, suicide attempts using firearms, which constitute just 5 percent of all fatal and nonfatal attempts, are highly lethal — more than 90 percent of all suicidal acts by firearm are fatal. By comparison, individuals who use drugs to attempt suicide, which constitute 75 percent of all attempts, die in the attempt less than 3 percent of the time.

The researchers recommend that firearm owners take steps to make their homes safer. “Removing all firearms from one’s home is one of the most effective and straightforward steps that household decision-makers can take to reduce the risk of suicide,” says Miller. “Removing firearms may be especially effective in reducing the risk of suicide among adolescents and other potentially impulsive members of their home. Short of removing all firearms, the next best thing is to make sure that all guns in homes are very securely locked up and stored separately from secured ammunition. In a nation where more than half of all suicides are gun suicides and where more than one in three homes have firearms, one cannot talk about suicide without talking about guns,” he adds.

The bottom line, says Miller, is that “people are less likely to die from attempting suicide when they don’t have access to guns in homes.”

The study was supported by the Joyce Foundation.

Source: Harvard University

Bugs in the gut are known as gut microbes and they live symbiotically in human and animal bodies, playing an important role in metabolism. Abnormalities in some types of gut microbes have recently been linked to diseases such as diabetes and obesity.

Today’s research, published in the Journal of Proteome Research, was based on a study in which 24 dogs were paired, with one dog in each pair given 25% less food than the other. Those with a restricted intake of calories lived, on average, about 1.8 years longer than those with a greater intake and they had fewer problems with diseases such as diabetes and osteoarthritis, plus an older median age for onset of late-life diseases.

The researchers, from Imperial College London, Nestlé Research Center (NRC) and Nestlé-Purina, found long-term differences in the metabolism of the dietary-restricted and non-dietary-restricted dogs. Metabolic profile plays a key role in determining animals’ response to illness and their susceptibility to disease.

The scientists believe that differences in the makeup of gut microbes between the two sets of dogs could partly explain their metabolic differences. The dogs that were not on a restricted diet had increased levels of potentially unhealthy aliphatic amines in their urine. These reflect reduced levels of a nutrient that is essential for metabolising fat, known as choline, indicating the presence of a certain makeup of gut microbe in the dogs. This makeup of gut microbes has been associated in recent studies with the development of insulin resistance and obesity.

Professor Jeremy Nicholson Opens in new window from Imperial College London said: “This fascinating study was primarily focused on trying to find optimised nutritional regimes to keep pet animals such as dogs healthy and as long-lived as possible. However these types of life-long studies can help us understand human diseases and ageing as well, and that is the added bonus of being able to do long-term non-invasive metabolic monitoring.”

The researchers suggest that part of the healthier metabolic profiles of dogs on a restricted diet is related to their changed gut microbial activity, which in turn contributes to their generally improved health and longer lifespan. However, they also found that the overall effects of ageing on restricted and non-restricted animals exerted a greater effect on the metabolic profile than dietary restriction. This in itself is interesting as the lifelong metabolic trajectories of large animals had never been studied in this detail before and such information might be of relevance to ageing humans and their diseases. The team believes that one important outcome of this work will be the ability to improve the design of products’ nutritional properties that mimic the health benefits of dietary restriction in pet dogs.

Source: Imperial College London

Scientists have confirmed the existence of protein in soft tissue recovered from the fossil bones of a 68 million-year-old Tyrannosaurus rex (T. rex) and a half-million-year-old mastodon.

Their results may change the way people think about fossil preservation and present a new method for studying diseases in which identification of proteins is important, such as cancer.

When an animal dies, protein immediately begins to degrade and, in the case of fossils, is slowly replaced by mineral. This substitution process was thought to be complete by 1 million years. Researchers at North Carolina State University (NCSU) and Harvard Medical School now know otherwise.

The researchers’ findings appear as companion papers in this week’s issue of the journal Science.

“Not only was protein detectably present in these fossils, the preserved material was in good enough condition that it could be identified,” said Paul Filmer, program director in the National Science Foundation (NSF) Division of Earth Sciences, which funded the research. “We now know much more about what conditions proteins can survive in. It turns out that some proteins can survive for very long time periods, far longer than anyone predicted.”

Mary Schweitzer of NCSU and the North Carolina Museum of Natural Sciences discovered soft tissue in the leg bone of a T. rex and other fossils recovered from the Hell Creek sediment formation in Montana.

After her chemical and molecular analyses of the tissue indicated that original protein fragments might be preserved, she turned to colleagues John Asara and Lewis Cantley of Harvard Medical School, to see if they could confirm her suspicions by finding the amino acid used to make collagen, a fibrous protein found in bone.

Bone is a composite material, consisting of both protein and mineral. In modern bones, when minerals are removed, a collagen matrix–fibrous, resilient material that gives the bones structure and flexibility–is left behind. When Schweitzer demineralized the T. rex bone, she was surprised to find such a matrix, because current theories of fossilization held that no original organic material could survive that long.

“This information will help us learn more about evolutionary relationships, about how preservation happens, and about how molecules degrade over time, which could have important applications in medicine,” Schweitzer said.

To see if the material had characteristics indicating the presence of collagen, which is plentiful, durable and has been recovered from other fossil materials, the scientists examined the resulting soft tissue with electron microscopy and atomic force microscopy. They then tested it against various antibodies that are known to react with collagen. Identifying collagen would indicate that it is original to T. rex–that the tissue contains remnants of the molecules produced by the dinosaur.

“This is the breakthrough that says it’s possible to get sequences beyond 1 million years,” said Cantley. “At 68 million years, it’s still possible.”

Asara and Cantley successfully sequenced portions of the dinosaur and mastodon proteins, identifying the amino acids and confirming that the material was collagen. When they compared the collagen sequences to a database that contains existing sequences from modern species, they found that the T. rex sequence had similarities to those of chickens, and that the mastodon was more closely related to mammals, including the African elephant.

The protein fragments in the T. rex fossil appear to most closely match amino acid sequences found in collagen of present-day chickens, lending support to the idea that birds and dinosaurs are evolutionarily related.

“Most people believe that birds evolved from dinosaurs, but that’s based on the ‘architecture’ of the bones,” Asara said. “This finding allows us the ability to say that they really are related because their sequences are related.”

“Scientists had long assumed that the material in fossil bones would not be preserved after millions of years of burial,” said Enriqueta Barrera, program director in NSF’s Division of Earth Sciences. “This discovery has implications for the study of similarly well-preserved fossil material.”

The research was also funded by grants from the David and Lucille Packard Foundation, the Paul F. Glenn Foundation and Beth Israel Deaconess Medical Center.

Source: NSF