Yearly Archives: 2007

Primates Expect Others To Act Rationally:

When trying to understand someone’s intentions, non-human primates expect others to act rationally by performing the most appropriate action allowed by the environment, according to a new study by researchers at Harvard University. The work was led by Justin Wood, a graduate student in the Department of Psychology in the Faculty of Arts and Sciences at Harvard, with David Glynn, a research assistant, and Marc Hauser, professor of psychology at Harvard, along with Brenda Phillips of Boston University.

Brain’s Timing Linked With Timescales Of The Natural Visual World:

Researchers have long attempted to unravel the cryptic code used by the neurons of the brain to represent our visual world. By studying the way the brain rapidly and precisely encodes natural visual events that occur on a slower timescale, a team of Harvard bioengineers and brain scientists from the State University of New York have moved one step closer towards solving this riddle.

Role Reversal: Humans Suck Life Out Of Leeches:

Global warming may be to blame for the gradual extinction of cold-loving species, and the European land leech in particular, according to Ulrich Kutschera and colleagues from the University of Kassel in Germany and the Karl-Franzens-University of Graz in Austria.

Cell Phones Should Be Kept Away From Hospital Beds, Dutch Experts Say:

Cell phones should come no closer than one meter to hospital beds and equipment, according Dutch research published in the online open access journal, Critical Care. Scientists demonstrated that incidents of electromagnetic interference (EMI) from second and third generation mobile phones occurred even at distance of three meters.

The Hygiene Hypothesis: Are Cleanlier Lifestyles Causing More Allergies For Kids?:

A little dirt never hurt. But in today’s super-clean world, vaccinations, anti-bacterial soaps, and airtight doors and windows are keeping dirt and disease-causing germs at bay. While staying germ-free can prevent the spread of disease and infections, leading a cleanlier lifestyle may be responsible for an increase in allergies among children.

Adult Brain Can Change, Study Confirms:

It is well established that a child’s brain has a remarkable capacity for change, but controversy continues about the extent to which such plasticity exists in the adult human primary sensory cortex. Now, neuroscientists from MIT and Johns Hopkins University have used converging evidence from brain imaging and behavioral studies to show that the adult visual cortex does indeed reorganize–and that the change affects visual perception.

Ecologists Get To The Bottom Of Why Bears Rub Trees:

Ecologists have at last got to the bottom of why bears rub trees – and it’s not because they have itchy backs. Speaking at the British Ecological Society’s Annual Meeting in Glasgow the week of September 10, Dr Owen Nevin of the University of Cumbria will reveal that adult male grizzly bears use so-called “rub trees” as a way to communicate with each other while looking for breeding females, and that this behaviour could help reduce battles between the bears.

Females Promiscuous For The Sake Of Their Grandchildren:

Female animals that mate with multiple partners may be doing so to ensure the optimum health of their grandchildren, according to researchers at the universities of Leeds and Exeter. Despite mating being a risky business for females – not least with the threat of injury, sexually transmitted diseases and vulnerability to predators – polyandry (females taking multiple mates) is widespread in the animal kingdom.

Force For Democracy — Or Information Chaos? Expert Forum Spotlights Blogging:

Controversial Internet entrepreneur turned cultural critic Andrew Keen, who says the revolution of interactivity and user-generated content on the internet is leading to ‘less culture, less reliable news and a chaos of useless information’ is one contributor certain to ignite debate at the two-day conference at the University of York. The conference is funded by the Economic and Social Research Council (ESRC) through its e-Society programme.

Future Career Path Of Gifted Youth Can Be Predicted By Age 13 By SAT:

The future career path and creative direction of gifted youth can be predicted well by their performance on the SAT at age 13, a new study from Vanderbilt University finds. The study offers insights into how best to identify the nation’s most talented youth, which is a focus of the new $43 billion America Competes Act recently passed by Congress to enhance the United States’ ability to compete globally.

Polar Bear Population Predicted To Dwindle WIth Retreating Ice:

Future reduction of sea ice in the Arctic could result in a loss of 2/3 of the world’s polar bear population within 50 years according to a series of studies just released by the U.S. Geological Survey. Last December, Secretary of the Interior Dirk Kempthorne announced that the U.S. Fish and Wildlife Service (Service) was proposing to list the polar bear as a threatened species under the Endangered Species Act. In January 2008, following a one-year review period, the Service is expected to make a recommendation to Secretary Kempthorne on whether or not to list the polar bear as threatened.

A Balanced Memory Network:

A critical component of cognition is memory–the ability to store information, and to readily retrieve it on cue. Existing models postulate that recalled items are represented by self-sustained activity; that is, they are represented by activity that can exist in the absence of input. These models, however, are incomplete, in the sense that they do not explain two salient experimentally observed features of persistent activity: low firing rates and high neuronal variability. Here we propose a model that can explain both. The model makes two predictions: changes in synaptic weights during learning should be much smaller than the background weights, and the fraction of neurons selective for a memory should be above some threshold. Experimental confirmation of these predictions would provide strong support for the model, and constitute an important step toward a complete theory of memory storage and retrieval.

Adaptive Evolution of Conserved Noncoding Elements in Mammals:

Conservation of DNA sequences across evolutionary history is a highly informative signal for identifying regions with important biological functions. In particular, conserved noncoding regions have been shown to be good candidates for containing regulatory elements that have roles in gene regulation. Recent studies have found that there are many thousands of conserved noncoding elements (CNCs) in vertebrate genomes and have suggested possible functions for some of these elements, but the function of most CNCs remains unknown. To study the evolution of CNCs, we developed a statistical method to identify CNCs that show changes in evolutionary rates on particular branches of the mammalian phylogenetic tree. Those rate changes may indicate changes in the function of a CNC. We applied our method to CNCs of five mammalian genomes, and found that, indeed, many CNCs have experienced rate changes during their evolution. We also found a subset of CNCs showing accelerations in evolutionary rate that actually exceed the neutral rates, suggesting that adaptive evolution has shaped the evolution of those elements.

‘Alien’ Jaws Help Moray Eels Feed:

Moray eels have a unique way of feeding reminiscent of a science fiction thriller, researchers at UC Davis have discovered. After seizing prey in its jaws, a second set of jaws located in the moray’s throat reaches forward into the mouth, grabs the food and carries it back to the esophagus for swallowing.

More here and here (you can see the video on both places).
Migrating Squid Drove Evolution Of Sonar In Whales And Dolphins, Researchers Argue:

Behind the sailor’s lore of fearsome battles between sperm whale and giant squid lies a deep question of evolution: How did these leviathans develop the underwater sonar needed to chase and catch squid in the inky depths? Now, two evolutionary biologists at the University of California, Berkeley, claim that, just as bats developed sonar to chase flying insects through the darkness, dolphins and other toothed whales also developed sonar to chase schools of squid swimming at night at the surface.

Higher Social Skills Are Distinctly Human, Toddler And Ape Study Reveals:

Apes bite and try to break a tube to retrieve the food inside while children follow the experimenter’s example to get inside the tube to retrieve the prize, showing that even before preschool, toddlers are more sophisticated in their social learning skills than their closest primate relatives, according to a report published in the 7 September issue of the journal Science.

Human-Animal Hybrid Embryos Approved For Research In Britain:

The following is the statement by the Human Fertilisation and Embryo Authority, the body which oversees human embryo research in Britain. The group will allow the creation of part-human, part-animal hybrid embryos for research purposes. British regulations already require that human embryos for research purposes are destroyed within 14 days of their creation.

Failing Protection Of Africa’s National Parks:

For years, biologists in Africa have known that large mammals – including antelopes and their predators – were disappearing outside reserves. Now a raft of studies, published in the September 2007 issue of the African Journal of Ecology, show that we have moved beyond this. We are losing species from national parks, bastion of biodiversity conservation. Worryingly, this includes the continent’s crown jewels such as Tanzania’s Serengeti National Park.

Specific Neurons Involved In Memory Formation Identified:

In a remarkable new study, scientists at The Scripps Research Institute have unlocked one of the secrets of how memory is formed. Working with a unique breed of transgenic mice, the new study has shown for the first time that the same neurons activated during fear conditioning are, in fact, reactivated during memory retrieval.

Nicotine In Breast Milk Disrupts Infants’ Sleep Patterns:

A study from the Monell Chemical Senses Center reports that nicotine in the breast milk of lactating mothers who smoke cigarettes disrupts their infants’ sleep patterns.

River Blindness Parasite Becoming Resistant To Standard Treatment:

Ivermectin, the standard drug for treating river blindness (onchocerciasis), is causing genetic changes in the parasite that causes the disease, according to a new study by Roger Prichard (McGill University, Canada) and colleagues, published on August 30, 2007 in the open-access journal PLoS Neglected Tropical Diseases.

Small Animal Imaging Facility Is Big Boon To Research:

When powerful magnets line up the body’s protons before radiofrequency waves can grab their attention away, it’s called spin physics. When signals generated by the movement are mathematically transformed into dramatic images of hearts, lungs and other organs it’s called a magnetic resonance image.

First Beehives In Ancient Near East Discovered:

Archaeological proof of the Biblical description of Israel really as “the land of milk and honey” (or at least the latter) has been uncovered by researchers from the Hebrew University of Jerusalem Institute of Archaeology.

Fighting Malaria By Tricking Mosquito’s Sense Of Smell:

By mapping a specialized sensory organ that the malaria mosquito uses to zero in on its human prey, an international team of researchers has taken an important step toward developing new and improved repellents and attractants that can be used to reduce the threat of malaria, generally considered the most prevalent life-threatening disease in the world.

Neurotransmitter Current Not Flowing Through Ion Channels:

In studying how neurotransmitters travel between cells — by analysis of events in the dimensions of nanometers — Cornell researchers have discovered that an electrical current thought to be present during that process does not, in fact, exist.

How Drones Find Queens: Odorant Receptor For Queen Bee Pheromone Identified:

The mating ritual of the honey bee is a mysterious affair, occurring at dizzying heights in zones identifiable only to a queen and the horde of drones that court her. Now a research team led by the University of Illinois has identified an odorant receptor that allows male drones to find a queen in flight. The receptor, on the male antennae, can detect an available queen up to 60 meters away.

Gender And Handedness Influences On Monkeys’ Brains Similar To Humans:

Capuchin monkeys are playful, inquisitive primates known for their manual dexterity, complex social behavior, and cognitive abilities. New research now shows that just like humans, they display a fundamental sex difference in the organization of the brain, specifically in the corpus callosum, the region that connects the two cerebral lobes.

Investigating The Evolution Of Drug Resistance In Malaria Parasites:

Funded by a $1.5 million grant from the National Institutes of Health, scientists at Binghamton University, State University of New York, hope to understand how the malaria parasite Plasmodium falciparum evolved resistance to the once-effective medication chloroquine.

There are 38 new articles on PLoS ONE today. Below are some of my own picks, but you look around, read what you like, rate, comment and annotate:
Studying Seabird Diet through Genetic Analysis of Faeces: A Case Study on Macaroni Penguins (Eudyptes chrysolophus):

Determining what seabirds have eaten is typically accomplished with stomach flushing. Here, Deagle and colleagues use non-invasive DNA-based analysis of faeces as an alternative way to examine the diet of Macaroni penguins on Heard Island in the southern Indian Ocean. Their results show that the technique can detect changes in the birds’ diet over time and suggest it will be useful in long-term monitoring studies.

Plants Attract Parasitic Wasps to Defend Themselves against Insect Pests by Releasing Hexenol:

Many plants release compounds that evaporate easily and defend the plant against insects by attracting natural enemies of those insects. This study examined the attraction of leafminer parasitoids to plants damaged by leafminers. The results reveal that the compound hexenol, released by diverse plant species following mechanical damage, attracts a leafminer parasite to the plant.

Malaria in Africa: Vector Species’ Niche Models and Relative Risk Maps:

A central theoretical goal of epidemiology is the construction of spatial models of disease prevalence and risk, including maps for the potential spread of infectious disease. We provide three continent-wide maps representing the relative risk of malaria in Africa based on ecological niche models of vector species and risk analysis at a spatial resolution of 1 arc-minute (9 185 275 cells of approximately 4 sq km). Using a maximum entropy method we construct niche models for 10 malaria vector species based on species occurrence records since 1980, 19 climatic variables, altitude, and land cover data (in 14 classes). For seven vectors (Anopheles coustani, A. funestus, A. melas, A. merus, A. moucheti, A. nili, and A. paludis) these are the first published niche models. We predict that Central Africa has poor habitat for both A. arabiensis and A. gambiae, and that A. quadriannulatus and A. arabiensis have restricted habitats in Southern Africa as claimed by field experts in criticism of previous models. The results of the niche models are incorporated into three relative risk models which assume different ecological interactions between vector species. The “additive” model assumes no interaction; the “minimax” model assumes maximum relative risk due to any vector in a cell; and the “competitive exclusion” model assumes the relative risk that arises from the most suitable vector for a cell. All models include variable anthrophilicity of vectors and spatial variation in human population density. Relative risk maps are produced from these models. All models predict that human population density is the critical factor determining malaria risk. Our method of constructing relative risk maps is equally general. We discuss the limits of the relative risk maps reported here, and the additional data that are required for their improvement. The protocol developed here can be used for any other vector-borne disease.

Is Transcriptional Regulation of Metabolic Pathways an Optimal Strategy for Fitness?:

Transcriptional regulation of the genes in metabolic pathways is a highly successful strategy, which is virtually universal in microorganisms. The lac operon of E. coli is but one example of how enzyme and transporter production can be made conditional on the presence of a nutrient to catabolize.
With a minimalist model of metabolism, cell growth and transcriptional regulation in a microorganism, we explore how the interaction between environmental conditions and gene regulation set the growth rate of cells in the phase of exponential growth. This in silico model, which is based on biochemical rate equations, does not describe a specific organism, but the magnitudes of its parameters are chosen to match realistic values. Optimizing the parameters of the regulatory system allows us to quantify the fitness benefit of regulation. When a second nutrient and its metabolic pathway are introduced, the system must further decide whether and how to activate both pathways.
Even the crudest transcriptional network is shown to substantially increase the fitness of the organism, and this effect persists even when the range of nutrient levels is kept very narrow. We show that maximal growth is achieved when pathway activation is a more or less steeply graded function of the nutrient concentration. Furthermore, we predict that bistability of the system is a rare phenomenon in this context, but outline a situation where it may be selected for.

Bonobo Handshake: What Makes Our Chimp-like Cousins So Cooperative?:

What’s it like to work with relatives who think sex is like a handshake, who organise orgies with the neighbours, and firmly believe females should be in charge of everything? On September 11, researcher Vanessa Woods will journey to Lola ya Bonobo Sanctuary in Congo with colleagues from the Max Planck Institute in Germany to study our mysterious cousin, the bonobo.

Rare Breeds Of Farm Animals Face Extinction:

With the world’s first global inventory of farm animals showing many breeds of African, Asian, and Latin American livestock at risk of extinction, scientists from the Consultative Group on International Agricultural Research (CGIAR) called for the rapid establishment of genebanks to conserve the sperm and ovaries of key animals critical for the global population’s future survival.

Ancient Pig DNA Study Sheds New Light On Colonization Of Europe By Early Farmers:

The earliest domesticated pigs in Europe, which many archaeologists believed to be descended from European wild boar, were actually introduced from the Middle East by Stone Age farmers, new research suggests.

Auto Immune Response Creates Barrier To Fertility; Could Be A Step In Speciation:

Plant biologists at the Max Planck Institute of Developmental Biology and the University of North Carolina at Chapel Hill have discovered that an autoimmune response, triggered by a small number of genes, can be a barrier to producing a viable offspring.

Population Movements And Money Remittances Spur Forest Regrowth:

A study of forest cover in El Salvador in the September issue of BioScience presents novel findings on how economic globalization, land policy changes, and monies sent to family members by emigrants have transformed agriculture and stimulated forest regrowth.

Inside The Brain Of A Crayfish:

Voyage to the bottom of the sea, or simply look along the bottom of a clear stream and you may spy lobsters or crayfish waving their antennae. Look closer, and you will see them feeling around with their legs and flicking their antennules – the small, paired sets of miniature feelers at the top of their heads between the long antennae. Both are used for sensing the environment. The long antennae are used for getting a physical feel of an area, such as the contours of a crevice. The smaller antennules are there to both help the creature smell for food or mates or dangerous predators and also to sense motion in the water that also could indicate the presence of food, a fling or danger. The legs also have receptors that detect chemical signatures, preferably those emanating from a nice hunk of dead fish.

Male Deer Are Born To Live Fast, Die Young:

In the September issue of The American Naturalist, Juan Carranza (Biology and Ethology Unit, University of Extremadura, Spain) and Javier Pérez-Barbería (Macaulay Institute, United Kingdom) offer a new explanation for why males of ungulate species subjected to intense competition are born with lower survival expectancies than females.

Lack Of Sleep Among New School-goers Leads To Behavioral, Cognitive Problems:

The first investigation of developmental sleep duration patterns throughout childhood shows that children just beginning school and who get little sleep are more likely to have behavioral and cognitive problems in the classroom, according to a new study.

Teenagers’ Use Of Cell Phones After Bedtime Contributes To Poor Sleep:

The use of modern means of interpersonal and mass communication has become an essential part of being young. Technology has enabled two people to connect with each other virtually anywhere and at any time, a privilege that, according to new research, is often abused by youngsters and cutting into their sleep time. A new study finds that cell phone use after bedtime is very prevalent among adolescents, and its use is related to increased levels of tiredness after one year.

Obesity And The Central Nervous System — The State Of The Art:

The past decade has witnessed an explosion of information regarding the role of the central nervous system (CNS) in the development of obesity and the influence of peripheral, hormonal signals that regulate CNS function to regulate food intake and metabolism. A symposium held recently in Washington, DC, organized by The Journal of Physiology, focused on recent work in talks by leaders in the field.