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Last Updated: Nov 18, 2006 - 12:32:53 PM |
Special Topics
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Evolution
New approach will pinpoint genes linked to evolution of human brain
Six million years ago, chimpanzees and humans diverged from a common ancestor and evolved into unique species. Now UCLA scientists have identified a new way to pinpoint the genes that separate us from our closest living relative � and make us uniquely human.
Nov 14, 2006 - 5:46:00 PM
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Accelerating Loss of Ocean Species Threatens Human Well-being
In a study published in the November 3rd issue of the journal, Science, an international group of ecologists and economists, including lead author, Boris Worm of Dalhousie University, show that the loss of biodiversity is profoundly reducing the ocean�s ability to produce seafood, resist diseases, filter pollutants, and rebound from stresses such as over-fishing and climate change. The study reveals that every species lost causes a faster unraveling of the overall ecosystem. Conversely every species recovered adds significantly to overall productivity and stability of the ecosystem and its ability to withstand stresses.
Nov 3, 2006 - 4:06:00 AM
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Evolution
New genetic analysis forces re-draw of insect family tree
The family tree covering almost half the animal species on the planet has been re-drawn following a genetic analysis which has revealed new relationships between four major groups of insects. Scientists have found that flies and moths are most closely related to beetles and more distantly related to bees and wasps, contrary to previous theory.
Oct 29, 2006 - 10:26:00 PM
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Cell Phone Use Associated with Decline in Fertility
In an observational study, researchers from Cleveland, Mumbai, and New Orleans found that the number of hours in a day that a man uses his cell phone can affect all aspects of his sperm profile.
Oct 24, 2006 - 6:05:00 PM
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Marijuana-like Chemical Can Restore Sperm Function Lost to Tobacco Abuse
A compound chemically similar to those found in marijuana can improve the ability of smokers� sperm to bind to eggs. Researchers in Buffalo and Boston have previously shown that two-thirds of tobacco smokers� sperm showed a significant decline in the capacity to bind to an egg compared to that of non-smokers. They hypothesized that treating the smokers� sperm with a cannabinoid compound would improve sperm binding. Human sperm have chemical receptors that respond to both nicotine and cannabinoids- compounds like those found in marijuana.
Oct 24, 2006 - 6:02:00 PM
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Reporters struggle to cover comas in newspaper articles
Newspaper articles skew coverage of comas by focusing heavily on patients who are more likely to awaken and recover, thus possibly leading the public to believe that coma patients have better odds than they truly do. These findings of a Mayo Clinic study on how U.S. newspapers cover comas are published in the October issue of Mayo Clinic Proceedings. This study is the first of its kind and follows a study published earlier this year in Neurology on how comas are represented in film. The lead author of both articles is Eelco F.M. Wijdicks, M.D., a neurointensivist at Mayo Clinic in Rochester.
Oct 19, 2006 - 11:56:00 PM
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Drug Company Research Reports Should Be Read With Caution
A study published on bmj.com recently has found that reviews of drugs which are supported by the pharmaceutical industry are less transparent, and are more likely to reach favourable conclusion on drugs, than independent reviews.
Oct 12, 2006 - 1:19:00 PM
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Evolution
Giant insects might reign if only there was more oxygen in the air
The delicate lady bug in your garden could be frighteningly large if only there was a greater concentration of oxygen in the air, a new study concludes. The study adds support to the theory that some insects were much larger during the late Paleozoic period because they had a much richer oxygen supply, said the study's lead author Alexander Kaiser.
Oct 12, 2006 - 4:52:00 AM
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Evolution
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Reproduction
Infection Status Drives Interspecies Mating Choices in Fruit Fly Females
Hybridization is a constant possibility for two closely related species. Geographic isolation prevents interbreeding in some cases, but when the range of the two overlap, other mechanisms must come into play if they are to remain genetically distinct. Behavioral isolation is one such mechanism. If members of each group preferentially mate with their own kind, the two species can remain distinct even while residing together. Over time, such isolating behaviors may become more pronounced, and the genes governing them more widespread, a phenomenon termed �reinforcement.�
Oct 11, 2006 - 5:25:00 AM
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Ethics
Waiting For Trial Results Sometimes Unethical
Waiting for the results of randomised trials of public health interventions can cost hundreds of lives, especially in poor countries. Researchers in this week�s BMJ argue that, if the science is good, we should act before the trials are done.
Oct 5, 2006 - 1:17:00 AM
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Ethics
NHGRI Funds Assessment of Public Attitudes About Population-Based Studies on Genes and Environment
The National Human Genome Research Institute (NHGRI), part of the National Institutes of Health (NIH), today announced it has awarded $2 million to the Genetics and Public Policy Center of the Berman Bioethics Institute at Johns Hopkins University to conduct a public discussion about future potential large U.S. population-based studies examining the roles of genes and environment in human health.
Sep 29, 2006 - 7:56:00 PM
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Evolution
Mother birds give a nutritional leg up to chicks with unattractive fathers
Mother birds deposit variable amounts of antioxidants into egg yolks, and it has long been theorized that females invest more in offspring sired by better quality males. However, a study from the November/December 2006 issue of Physiological and Biochemical Zoology shows that even ugly birds get their day. Providing new insight into the strategic basis behind resource allocation in eggs, the researchers found that female house finches deposit significantly more antioxidants, which protect the embryo during the developmental process, into eggs sired by less attractive fathers.
Sep 26, 2006 - 10:38:00 PM
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Evolution
Mammals Evolve Faster on Islands!
The notion of islands as natural testbeds for evolutionary study is nearly as old as the theory of evolution itself. The restricted scale, isolation, and sharp boundaries of islands create unique selective pressures, often to dramatic effect. Following what’s known as the “island rule,” small animals evolve into outsize versions of their continental counterparts while large animals shrink. Once restricted to islands, small animals often lacked predators and the competition between species that constrained the growth of their relatives on the mainland. Large mammals, on the other hand, no longer had access to vast grasslands and other abundant food sources and grew smaller to survive. Giant tortoises and iguanas still inhabit the Galápagos and a few other remote islands today, but only fossils remain of the dwarf hippopotami, elephants, and deer that once lived on islands in Indonesia, the Mediterranean, and the Pacific Ocean.
Sep 13, 2006 - 3:48:00 AM
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Evolution
A Bacterial Protein Puts a New Twist on DNA Transcription
For organisms to adapt, develop, and simply live, they must regulate hundreds to thousands of genes, making fine-tuned, precisely timed adjustments to produce the specific complement of proteins required for the occasion. For bacteria, this task falls largely to proteins called sigma factors. These small proteins associate with RNA polymerase, the enzyme that mediates gene transcription, to form a complex called the holoenzyme. The holoenzyme, guided by the sigma factor, recognizes promoter regions, which are specific DNA sequences that precede protein-coding sequences and mark the transcription start site. Sigma factors also contribute to transcription by facilitating DNA strand separation, which must occur before RNA polymerase can begin copying the DNA code. Once transcription begins, the sigma factor disengages from the RNA polymerase, becoming available for new joint ventures with different RNA polymerases.
Aug 16, 2006 - 9:16:00 AM
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Ethics
Physicians More Likely To Disclose Medical Errors That Would Be Apparent To The Patient
While physicians in the United States and Canada generally support disclosing medical errors to patients, they vary widely in when and how they would tell patients an error had occurred, according to two articles in the August 14/28 issue of the Archives of Internal Medicine, one of the JAMA/Archives journals. Research has revealed that most patients want detailed information following a medical error, including an explicit statement that an error has occurred, an apology, information about why the error happened and an explanation of what will be done to prevent future errors. However, less than half of harmful errors may be disclosed to patients, according to background information in the articles. This may diminish trust in physicians and may also increase the risk that patients will file malpractice lawsuits.
Aug 15, 2006 - 1:26:00 PM
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Dissecting Doctor Patient Dialogue
The book targets sociologists, communication experts and medical professionals, and ultimately aims to understand the social organization of medical talk while helping to improve doctor-patient relationships, Maynard says. The sociologist co-edited the anthology with John Heritage, a professor of sociology at the University of California, Los Angeles.
Aug 9, 2006 - 3:12:00 PM
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Evolution
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Reproduction
Why Does Sex Exist?
Why does sex exist? A long-popular view holds that sexual reproduction creates new gene combinations that help the next generation resist rapidly co-evolving parasites. Each species constantly changes to achieve the same result�evolutionary advantage�prompting evolutionary biologists to dub this hypothesis the Red Queen (who tells Alice in Through the Looking Glass �it takes all the running you can do, to keep in the same place�).
Aug 7, 2006 - 1:51:00 PM
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Evolution
Pseudogenes Research Reinforces Theory of Evolution
Scientists led by a Children�s Hospital of Pittsburgh geneticist have found new evidence that a category of genes known as pseudogenes serve no function, an important finding that bolsters the theory of evolution.
Aug 2, 2006 - 11:54:00 AM
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Evolution
Non-human primates may be linchpin in evolution of language
When contemplating the coos and screams of a fellow member of its species, the rhesus monkey, or macaque, makes use of brain regions that correspond to the two principal language centers in the human brain, according to research conducted by scientists at the National Institute on Deafness and Other Communication Disorders (NIDCD) and the National Institute of Mental Health (NIMH), two of the National Institutes of Health. The finding, published July 23 in the advance online issue of Nature Neuroscience, bolsters the hypothesis that a shared ancestor to humans and present-day non-human primates may have possessed the key neural mechanisms upon which language was built.
Jul 24, 2006 - 7:33:00 PM
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Evolution
Primates developed close-up eyesight to avoid a dangerous predator
The ability to spot venomous snakes may have played a major role in the evolution of monkeys, apes and humans, according to a new hypothesis by Lynne Isbell, professor of anthropology at UC Davis. Primates have good vision, enlarged brains, and grasping hands and feet, and use their vision to guide reaching and grasping. Scientists have thought that these characteristics evolved together as early primates used their hands and eyes to grab insects and other small prey, or to handle and examine fruit and other foods.
Jul 22, 2006 - 7:15:00 PM
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Ethics
Doctors inadvertently help terminally ill patients to die sooner
An Australian psychiatric study has found that doctors may be inadvertently contributing to the desire of many terminally ill patients to die sooner rather than later.
Jun 27, 2006 - 2:48:00 AM
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Evolution
Parsing the Functional Fields of the Auditory Cortex
No self-respecting concertgoer of a certain era would consider wearing earplugs at a show, but that was long before Pete Townsend and other rock icons spoke out about the risk of deafness. Today, most people recognize that high-intensity noise causes hearing loss�except maybe for those iPod users who routinely blast earsplitting music straight into their brains.
Jun 23, 2006 - 12:43:00 AM
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Evolution
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Reproduction
Declining Human Fertility is Evolutionary Adaptation
Before society criticises teenage girls for having sex behind the bike sheds and becoming pregnant, or women in their 60s for seeking IVF treatment, it is important to consider fertility not just in terms of the 21st century but in the context of the past 150,000 years.
Jun 21, 2006 - 2:52:00 PM
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Evolution
Study shows that threat displays may prevent serious physical harm
In a paper from the July issue of The American Naturalist, Kristopher Lappin (Northern Arizona University), Yoni Brandt (University of Toronto), Jerry Husak (Oklahoma State University), Joe Macedonia (Arizona State University), and Darrell Kemp (James Cook University), demonstrate that a threat display can provide accurate information about the performance of a weapon.
Jun 20, 2006 - 11:17:00 PM
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Evolution
How animals learn from each other
In an exciting study that provides new understanding of how animals learn--and learn from each other--researchers have demonstrated that bats that use frog acoustic cues to find quality prey can rapidly learn these cues by observing other bats. While numerous examples are known of instances where predators can use so-called "social learning" to learn new visual and olfactory cues associated with prey, this kind of learning of an acoustic cue had not been previously described.
Jun 20, 2006 - 12:33:00 AM
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Evolution
Thermal Adaptation in Bacterial Viruses
Assuming the absence of a massive asteroid strike, gamma ray burst, or other globally devastating event, the survival of a species depends on its ability to adapt to environmental changes. To understand how such adaptations occur in nature, scientists study much simpler systems in the lab. A classic lab evolution experiment uses evolutionary responses to temperature as a model for studying how an environmental variable affects the physical expression (phenotype) of an organism's genes. Biologists have typically focused either on the range of physiological responses to temperature or on the genetic changes underlying variations in temperature.
Jun 10, 2006 - 1:16:00 PM
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Evolution
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Reproduction
Genetic quality of sperm worsens as men get older
New research indicates that the genetic quality of sperm worsens as men get older, increasing a man's risk of being infertile, fathering unsuccessful pregnancies and passing along dwarfism and possibly other genetic diseases to his children. A study led by scientists at Lawrence Livermore National Laboratory (LLNL) and the University of California, Berkeley, found a steady increase in sperm DNA fragmentation with increasing age of the study participants, along with increases in a gene mutation that causes achondroplasia, or dwarfism. The first changes were observed in men in their early reproductive years. Earlier research by the same team indicated that male reproductive ability gradually worsens with age, as sperm counts decline and the sperm lose motility and their ability to swim in a straight line. In the current study, the researchers analyzed DNA damage, chromosomal abnormalities and gene mutations in semen samples from the same subjects � 97 healthy, non-smoking LLNL employees and retirees between 22 and 80 years old � and found that sperm motility showed a high correlation with DNA fragmentation, which is associated with increased risk of infertility and a reduced probability of fathering a successful pregnancy.
Jun 8, 2006 - 4:46:00 PM
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Evolution
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Reproduction
Songbirds boost size of eggs when hearing sexy song
When the females started egg-laying they varied the size of their eggs in the nest according to the attractiveness of the male's song. That is, the more attractive the song, the larger the eggs.
Jun 8, 2006 - 6:04:00 AM
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Small naps a big help for young docs on long shifts
The first study to assess the benefits of naps for medical residents during extended shifts found that creating protected times when interns could sleep during a night on-call significantly reduced fatigue.
Jun 8, 2006 - 2:39:00 AM
Special Topics
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Evolution
Why women live longer than men
Despite research efforts to find modern factors that would explain the different life expectancies of men and women, the gap is actually ancient and universal, according to University of Michigan researchers. This skewed mortality isn't even unique to our species; the men come up short in common chimps and many other species, Kruger added. Kruger and co-author Randolph Nesse, a professor of psychology and psychiatry and director of the Evolution and Human Adaptation Program, argue that the difference in life expectancy stems from the biological imperative of attracting mates.
May 10, 2006 - 12:49:00 PM
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