A Blog Around The Clock

Why Are Lions Not As Big As Elephants?:

Carnivores are some of the widest ranging terrestrial mammals for their size, and this affects their energy intake and needs. This difference is also played out in the different hunting strategies of small and large carnivores. Smaller species less than 15-20 kg in weight specialize on very small vertebrates and invertebrates, which weigh a small fraction of their own weight, whereas larger species (>15-20 kg) specialize on large vertebrate prey near their own mass. While carnivores around the size of a lynx or larger can obtain higher net energy intake by switching to relatively large prey, the difficulty of catching and subduing these animals means that a large-prey specialist would expend twice as much energy as a small-prey specialist of equivalent body size. In a new article published by PLoS Biology, Dr. Chris Carbone and colleagues from the Institute of Zoology, Zoological Society of London reveal how this relationship might have led to the extinction of large carnivores in the past and why our largest modern mammalian carnivores are so threatened.

Closing A Loophole In The RNA World Hypothesis:

New scientific research may close a major loophole in the RNA world hypothesis, the idea that ribonucleic acid — not the fabled DNA that makes up genes in people and other animals — was the key to life’s emergence on Earth 4.6 billion years ago. That hypothesis states that RNA catalyzed all the biochemical reactions necessary to produce living organisms. Only later were those self-replicating RNA units joined by organisms based on DNA, which evolved into more advanced forms of life.

Marine Bacteria Can Create Environmentally Friendly Energy Source:

Bacteria in the world’s oceans can efficiently exploit solar energy to grow, thanks to a unique light-capturing pigment. This discovery was made by researchers at University of Kalmar in Sweden, in collaboration with researchers in Gothenburg, Sweden, and Spain. The findings are described in an article in the journal Nature.
“It was long thought that algae were the only organisms in the seas that could use sunlight to grow,” says Jarone Pinhassi, a researcher in Marine Microbiology at Kalmar University College. These microscopic algae carry out the same process as green plants on land, namely, photosynthesis with the help of chlorophyll.
In 2000 scientists in the U.S. found for the first time that many marine bacteria have a gene in their DNA that codes for a new type of light-capturing pigment: proteorhodopsin.
Proteorhodopsin is related to the pigment in the retina that enables humans to see colors. It should be possible for this pigment to enable marine bacteria to capture solar light to generate energy, but until now it had not been possible to confirm this hypothesis.

An Animated Key To The World Of Young People:

Animated films produced by children offer wide-ranging insights into how the younger generation see the world around them. This was the conclusion of an extensive project run by the “Zoom” Children’s Museum in Vienna, Austria. During a number of workshops, children and young people were given the opportunity to make their own animated films. The messages these films contain have now been interpreted as part of the project, which is supported by the Austrian Science Fund (FWF). Initial results indicate that the young generation is in two minds about technological progress and is extremely worried about our impact on the environment. The study also showed that gender stereotypes are far from being overcome.

New Group Of Algae Discovered: Picobiliphytes:

An international group of researchers has succeeded in identifying a previously unknown group of algae. As currently reported in the scientific journal Science, the newly discovered algae are found among the smallest members of photosynthetic plankton – the picoplankton (‘Picobiliphytes: A marine picoplanktonic algal group with unknown affinities to other Eukaroytes” Science, Vol. 316’). On account of the minute size of the organisms (no more than a few thousandth of a millimetre) and the appearance of phycobili-proteins, researchers have termed the new group Picobiliphyta.

Lost Dogs Found More Often Than Lost Cats, Study Suggests:

A lost dog is more likely to be reunited with its owner than a lost cat, according to two new studies. In one city in southwestern Ohio , researchers found that 71 percent of lost dogs were found, compared to just 53 percent of lost cats. More than a third of the recovered dogs were found by a call or visit to an animal shelter. More than one in four dogs were found because the animal wore a dog license or identification tag at the time of its disappearance.

Genetic Marker Predicts Pig Litter Size:

Bigger is often better where litter size is concerned, especially when it comes to piglets. Scientists with the Agricultural Research Service’s (ARS) U.S. Meat Animal Research Center in Clay Center, Neb., have identified a genetic marker that could help pig breeders select animals for increased uterine capacity and litter size. This genetic discovery could give swine breeding a boost in efficiency.

Rare Plant From Dinosaur Age:

A relic plant that once co-existed with dinosaurs has taken up residence in the University of Wisconsin-Madison botany greenhouses. Known as the Wollemi pine, the plant was presumed extinct until a “bushwalker” named David Noble discovered it in an Australian national park in 1994. As part of a worldwide effort to conserve and propagate the tree species – one of the oldest and rarest on earth – botany greenhouse director Mo Fayyaz recently purchased a foot-tall Wollemi pine seedling. A limited number of the plants just became available in the United States through National Geographic.

Stealth Technology Maintains Fitness After Sex: How ‘DNA Parasites’ Can Increase Spread Of Antibiotic Resistance:

Pathogens can become superbugs without their even knowing it, research published today in Science shows. ‘Stealth’ plasmids – circular ‘DNA parasites’ of bacteria that can carry antibiotic-resistance genes – produce a protein that increases the chances of survival and spread of the antibiotic-resistant strain. Low-cost plasmids, described for the first time in the study are a threat to use of antibiotics.

Large Size Crucial For Amazon Forest Reserves:

An international research team has discovered that the size of Amazon forest reserves is yet more important than previously thought. Their findings, to be published this week (January 12th) in the journal Science, underscore the importance of protecting the Amazon in large stretches of primary forest. The article summarizes bird survey results from the world’s largest and longest running experimental study of forest fragmentation — the Biological Dynamics of Forest Fragments Project, sponsored by the Smithsonian Tropical Research Institute, the Smithsonian Institution and the National Institute for Amazon Research, in Brazil.

States With Higher Levels Of Gun Ownership Have Higher Homicide Rates:

Firearms are used to kill two out of every three homicide victims in America.. In the first nationally representative study to examine the relationship between survey measures of household firearm ownership and state level rates of homicide, researchers at the Harvard Injury Control Research Center found that homicide rates among children, and among women and men of all ages, are higher in states where more households have guns. The study appears in the February 2007 issue of Social Science and Medicine.

There’s No Scent Like Home: New Research Shows Larval Fish Use Smell To Return To Coral Reefs:

Tiny larval fish living among Australia’s Great Barrier Reef spend the early days of their lives swept up in ocean currents that disperse them far from their places of birth. Given such a life history, one might assume that fish populations would be genetically homogeneous within the dispersal area. Yet the diversity of reef fish species is high and individual reefs contain different fish populations. For such rich biodiversity to have evolved, some form of population isolation is required. New research from MBL (Marine Biological Laboratory) Associate Scientist Gabriele Gerlach, MBL Adjunct Senior Scientist Jelle Atema, and their colleagues shows that some fish larvae can discriminate odors in ocean currents and use scent to return to the reefs where they were born. The olfactory imprinting of natal reefs sheds light on how such a wide diversity of species arose. The homing behavior of reef fishes, the researchers contend, could support population isolation and genetic divergence that may ultimately lead to the formation of new species.

World’s Largest Flower Evolved From Family Of Much Tinier Blooms:

The plant with the world’s largest flower — typically a full meter across, with a bud the size of a basketball — evolved from a family of plants whose blossoms are nearly all tiny, botanists write this week in the journal Science. Their genetic analysis of rafflesia reveals that it is closely related to a family that includes poinsettias, the trees that produce natural rubber, castor oil plants, and the tropical root crop cassava. [—] “For nearly 200 years rafflesia’s lineage has confounded plant scientists,” says Davis, an assistant professor of organismic and evolutionary biology in Harvard’s Faculty of Arts and Sciences. “As a parasite living inside the tissue of a tropical vine, the plant lacks leaves, shoots, or roots, making it difficult to compare to more conventional plants. Most efforts to place plants in the botanical tree of life in the past 25 years have tracked ancestry using molecular markers in genes governing photosynthesis. Rafflesia is a non-photosynthetic parasite, and those genes have apparently been abandoned, meaning that to determine its lineage we had to look at other parts of the plant’s genome.”

Prenatal Cocaine’s Lasting Cellular Effects:

Although the “crack baby” hysteria of the 1980s was greatly exaggerated, cocaine use during pregnancy can cause subtle but disabling cognitive impairments — attention deficits, learning disabilities and emotional problems. A recent study by investigators at the Vanderbilt Kennedy Center for Research on Human Development may help explain the long-term behavioral and neurological problems associated with prenatal exposure to cocaine. In a recent issue of the Journal of Neuroscience, Gregg Stanwood, Ph.D., and Pat Levitt, Ph.D., report that prenatal cocaine exposure in rabbits causes a long lasting displacement of dopamine receptors in certain brain cells, which alters their ability to function normally.

Musician In The Mirror: New Study Shows Brain Rapidly Forms Link Between Sounds And Actions That Produce Them:

A new imaging study shows that when we learn a new action with associated sounds, the brain quickly makes links between regions responsible for performing the action and those associated with the sound.

Big-brained Birds Survive Better In Nature:

Birds with brains that are large in relation to their body size have a lower mortality rate than those with smaller brains, according to new research published in the journal Proceedings of the Royal Society B: Biological Sciences. The research provides the first evidence for what scientists describe as the ‘cognitive buffer’ hypothesis – the idea that having a large brain enables animals to have more flexible behaviours and survive environmental challenges.

The Price Of Vanity: Mating With Showy Males May Reduce Offspring’s Ability To Fight Off Pathogens:

In many animals, males advertise to potential mates with showy traits, many of which are linked to testosterone levels. However, a new study suggests that, in fish, choosing a flashier mate may cause future generations to be more susceptible to pathogens. In the January 2007 issue of The American Naturalist, a new study by Judith Mank (Uppsala University, Sweden) finds that mating with males who possess showy traits — such as bright colors or long tails and fins — results in higher testosterone levels in males over many generations. Because male and female testosterone levels are correlated, female choice also results in an increase in female testosterone levels.

How Are Phenotypic Differences Between Sexes Related To Phenotypic Variation Within Sexes?:

It has long been recognized that sexually dimorphic traits — traits that are systematically different between members of different sex in the same species, such as peacocks’ tail feathers — tend to vary a great deal among individual males, and that much of this within-sex variation depends on individual condition. Indeed, theory predicts that sexual dimorphism will evolve based on condition dependence so that, among traits, a more pronounced difference between male and female should be associated with a stronger response to variation in condition.

Beavers Helping Frogs And Toads Survive:

The humble beaver, besides claiming a spot of honour on the Canadian nickel, is also helping fellow species survive. Though considered a pest because of the culvert-clogging dams it builds on streams, the beaver is an ally in conserving valuable wetland habitat for declining amphibian populations, a University of Alberta study shows.

Scientists Discover Stage At Which An Embryonic Cell Is Fated To Become A Stem Cell:

Cambridge scientists have discovered the stage at which some of the cells of a fertilised mammalian egg are fated to develop into stem cells and why this occurs. The findings of the study, which overturn the long-held belief that cells are the same until the fourth cleavage (division) of the embryo, are reported in the journal Nature.

A Curry A Day Keeps The Doctor Away?:

The chemical that gives spicy food its kick could hold the key to the next generation of anti-cancer drugs that will kill tumours with few or no side effects for the patient, say academics at The University of Nottingham. A study by the scientists, published online in the journal Biochemical and Biophysical Research Communications, has proven for the first time that the chemical compound capsaicin — which is responsible for the burning sensation when we eat chillies — can kill cells by directly targeting their energy source.

Controlling Sexual Compatibility Can Help Control Spread Of Some Invasive Species:

University of California, Riverside genetics Professor Norman Ellstrand led a team of researchers whose findings suggest that harnessing the sexual requirements of some plants can help control the establishment of invasive species. Using the California wild radish as their model, Ellstrand and graduate student Caroline Ridley at the UCR Department of Botany and Plant Sciences co-authored the research study titled Population size and relatedness affect fitness of self-incompatible invasive plants, published in the Dec. 29 edition of the Proceedings of the National Academy of Sciences. The current article originated from a doctoral dissertation project by former UCR graduate student Diane Elam. Fellow graduate student Karen Goodell also worked on the project. Elam is now with the U.S. Fish and Wildlife Service’s Sacramento office. Karen Goodell now teaches at Ohio State University.

Why Doesn’t The Immune System Attack The Small Intestine? New Study Provides Unexpected Answer:

Answering one of the oldest questions in human physiology, researchers at Dana-Farber Cancer Institute have discovered why the body’s immune system – perpetually on guard against foreign microbes like bacteria — doesn’t attack tissues in the small intestine that harbor millions of bacteria cells. In a study in the February issue of Nature Immunology, and which is currently available on the journal’s Web site as an advanced online publication, investigators led by Shannon Turley, PhD, of Dana-Farber identify an unlikely group of peacemakers: lymph node cells that instruct key immune system cells to leave healthy tissue alone. The finding, which illuminates a previously unknown corner of the human immune system, may lead to new forms of treatment for autoimmune diseases such as Type 1 diabetes and multiple sclerosis.

European Space Agency Launches New Project To Protect Biodiversity:

The world’s biodiversity is vanishing at an unprecedented rate – around 100 species every day – due to factors such as land use change and pollution. Addressing this threat, world governments agreed through the UN Convention on Biological Diversity to reduce significantly the current rate of biodiversity loss by 2010. To support this initiative, ESA has kicked off its new DIVERSITY project.

Researcher Placing Eye Implants In Cats To Help Humans See:

In “Star Trek: The Next Generation,” Geordi La Forge is a blind character who can see through the assistance of special implants in his eyes. While the Star Trek character “lives” in the 24th century, people living in the 21st century may not have to wait that long for the illuminating technology. Kristina Narfstrom, a University of Missouri-Columbia veterinary ophthalmologist, has been working with a microchip implant to help blind animals “see.” According to Narfstrom, the preliminary results are promising.

Children’s Packed Lunches: Are They Even Worse Than Turkey Twizzlers?:

Packed lunches taken to school by 7-year olds are even less healthy than school meals used to be before English TV chef Jamie Oliver set out to reform them. The Children of the 90s study, based at the University of Bristol, has revealed that in the year 2000, school meals were every bit as bad as Jamie Oliver suggested – but that children given packed lunches instead were even worse off nutritionally.

Adding Activity To Video Games Fights Obesity, Study Shows:

If playing video games makes kids less active — and contributes to obesity — why not create more video games that require activity? That’s the question prompted by a Mayo Clinic research study published in the current issue of the medical journal Pediatrics.

Benefits Of Testosterone Treatment Unknown, Research Shows:

Little research exists demonstrating that testosterone is both safe from the cardiovascular standpoint and effective to treat sexual dysfunction, reveal Mayo Clinic researchers in two new studies. In articles published in the January issue of Mayo Clinic Proceedings, Mayo Clinic physicians call for large studies to help clinicians and patients make informed decisions about when testosterone should be prescribed.

Education Does Not Protect Against Age-related Memory Loss, Say Researchers:

Adults over 70 with higher levels of education forgot words at a greater rate than those with less education, according to a new study from the University of Southern California. The findings, published in the current issue of Research on Aging, suggest that after age 70, educated adults may begin to lose the ability to use their schooling to compensate for normal, age-related memory loss.