Size did matter
The mystery of giant sperm present in some living animal groups today has taken on a new dimension. In one group of micro-crustaceans new evidence shows the feature is at least 100 million years old.
Renate Matzke-Karasz, from Ludwig-Maximilians-Universitt Munich (Germany), has led an interna...
Princeton geoscientist offers new evidence that meteorite did not wipe out dinosaurs
A Princeton University geoscientist who has stirred controversy with her studies challenging a popular theory that an asteroid wiped out the dinosaurs has compiled powerful new evidence asserting her position.
Gerta Keller, whose studies of rock formations at many sites in the United States, Me...
Evidence of the 'Lost World' -- did dinosaurs survive the end Cretaceous extinctions?
The Lost World, Sir Arthur Conan Doyle's account of an isolated community of dinosaurs that survived the catastrophic extinction event 65 million years ago, has no less appeal now than it did
when it was written a century ago. Various Hollywood versions have tried to recreate the lost world of din...
Study: Did early climate impact divert a new glacial age?
SAN FRANCISCO The common wisdom is that the invention of the steam engine and the advent of the coal-fueled industrial age marked the beginning of human influence on global climate.
But gathering physical evidence, backed by powerful simulations on the world's most advanced computer climate mo...
How did chemical constituents essential to life arise on primitive Earth?
Experiments show that simple molecules can combine chemically rather than biologically to form the building blocks of DNA, the key component of all life forms. These processes might have taken place on primitive earth, but how they occur is an unsolved puzzle.
Chemists at the University of Geor...
How did bilaterally symmetric flowers evolve from radially symmetric ones?
bilaterally symmetric flowers evolve from radially symmetric ones? To address this important question, geneticists Francisco Perfectti and Juan Pedro M. Camacho, and ecologist José M. Gómez (Universidad de Granada, Spain) explored how different flower shapes affected plant fitness in natura...
Dinosaurs -- stones did not help with digestion
The giant dinosaurs had a problem. Many of them had narrow, pointed teeth, which were more suited to tearing off plants rather than chewing them. But how did
they then grind their food? Until recently many researchers have assumed that they were helped by stones which they swallowed. In their muscu...
How did cactuses evolve?
In a groundbreaking new study in the June issue of American Naturalist, Erika J. Edwards (Yale University and University of California, Santa Barbara) and Michael J. Donoghue (Yale University) explore how leafy, "normal" plants evolved into the leafless succulent cactus.
"The cactus form is often...
Retrovirus struck ancestors of chimpanzees and gorillas millions of years ago, but did not affect ancestral humans
The ancestors of chimpanzees and gorillas were infected with a deadly retrovirus about three to four million years ago, but there is no evidence it infected ancestors of modern-day humans, according to research by genome scientists. The virus struck after humans had split off the evolutionary tree ...
Carnegie donates landmark clones to biology
...onium accumulated on the early Earth. This mechanism has been retained although a single mutation can make the transporters work independently. So why did
this simpler mutation not succeed? The researchers believe that there must still be selective pressure on the system. The simplest explanation is that...
AGU journal highlights -- Aug. 6, 2009
...tion may have existed for thousands of years on Mars during the Hesperian epoch, which has been thought to be a period during which surface conditions did
not allow significant hydrological activity. The authors suggest that the sedimentary deposits associated with the lake in Shalbatana Vallis should be...
Climate-caused biodiversity booms and busts in ancient plants and mammals
...mammals during the Paleocene and Eocene (65 million to 35 million years ago) and that only at the end of the Eocene, when Antarctic glaciations began, did
Earth's climate deteriorate enough to cause observable changes in land mammal diversity.
"Our paper documents the fact that global change affected ...
More than half of Texas physicians do not always recommend HPV vaccine to girls
...ional organizations or professional conferences an important source of information were almost twice as likely to recommend the vaccine than those who did
not consider these sources valuable.
"Most physicians are aware of the vaccine and what it prevents, but they may lack knowledge about issues of s...
Women often opt to surgically remove their breasts, ovaries to reduce cancer risk
Most of the women, specifically those aged 35 to 45 years, opted for surgery within the first two years after the genetic mutation test, but some did
not make a decision until seven years later.
"This is a very interesting study. It fleshes out some of what we know about adoption of risk reductio...
Abnormal brain circuits may prevent movement disorder
...s from one part of the circuit to the other. Those with only one lesion in the circuit developed the debilitating movements and those with two lesions did
not. "There is something about this second lesion that is protective," the authors concluded. "We found a consistent cerebellar pathway problem in all...
Understanding how weeds are resistant to herbicides
...ern Illinois, one of the things you want to know in managing resistance is, did
resistance evolve or occur here once and then a farmer moved a combine and that's how resistance got down here? Or did
resistance occur here and independently down in southern Illinois?"
Hormone levels contribute to stress resilience
...d in response to stress. Although medical scientists have known for over a decade that DHEA provides beneficial, anti-stress effects in animals, they did
not know until now whether this was also true for humans.
The scientists completed psychological and hormone assessments on a group of soldiers the ...
New insights into health and environmental effects of carbon nanoparticles
...and realized that such transfer could also occur between flies and humans in the future. The transfer involved very low levels of nanoparticles, which did
not have adverse effects on the fruit flies. Since larvae can tolerate very high doses of nanoparticles in the diet, but adult flies show very differ...
Growing evidence of marijuana smoke's potential dangers
...d significantly more damage to cells and DNA than tobacco smoke, the researchers note. However, tobacco smoke caused chromosome damage while marijuana did
Sustainable agriculture at the ESA Annual Meeting
...roplands ranging from 2 percent to about 80 percent natural vegetation. She found that as the proportion of natural area or complexity increased, so did
the numbers of natural enemies in the croplands.
Chaplin-Kramer shows that increases in predators didn't always result in fewer aphids in the cropl...
Animal and plant communication at the ESA Annual Meeting
...ith one another, she also wondered if the bugs were mimicking the scent of the ants. When she and her colleagues immobilized the bugs, the ants still did
not attack them. But when the researchers washed the bugs in a chemical solvent and returned them to the plants, the ants immediately swarmed the bugs...
The way you eat may affect your risk for breast cancer
...o these people."
Previous studies have shown that intermittent calorie restriction provided greater protection from mammary tumor development than did
the same overall degree of restriction, which was implemented in a chronic fashion. The researchers compared changes of a growth factor (IGF-1) in rel...
Holding breath for several minutes elevates marker for brain damage
...he breath hold and at fixed intervals for the two hours following the end of the breath hold. The researchers also measured arterial blood gases. They did
the same measurements on the individuals in the control group, but the controls rested on their backs for the entire experiment, without performing th...
Protecting cells from their neighbors
...o universal", explains Casanova.
In the 1960s, Drosophila was the model in which researchers described a phenotype named pole hole. Embryos, that did
not survive, showed a cavity in one of the poles of the egg in which cells were lacking. "It was thought that this was a problem related to the germ l...
Drug-proof zebrafish reveal secrets of addiction
...ation of addictive behaviour".
The team used the mutagenic chemical ENU to generate hundreds of mutant zebrafish. From these, they bred a line that did
not respond to amphetamine administration (despite the presence of the drug in the fish's brain) but that appeared to be normal in all other ways. As ...
August 2009 Geology and GSA Today media highlights
...the steppe bison, woolly mammoth, Yukon horse, western camel, American mastodon, American lion, the short-faced bear and the helmeted musk-ox. But how did
this remote Arctic region support such a diverse array of grazing megafauna? This is the question addressed by Duane Froese of the University of Alber...
UC San Diego engineer provides insights to decades-old DNA squabble
...oped an innovative experimental approach called Electron microscopy assisted nucleosome capture technique to corroborate Arya's findings.
"What we did
was extract the most important features of DNA and the associated proteins in the model, using techniques called coarse-graining," Arya explained. "Yo...
Antibody targeting of glioblastoma shows promise in preclinical tests, say Lombardi researchers
...ody prevented tumors from growing. For example untreated tumors grew to an average size of 350 cubic millimeters after three weeks, but treated tumors did
not grow beyond their initial 25 cubic millimeters.
Wellstein says a phase I clinical trial of the therapy is in the discussion stage, but much re...
Jet-propelled imaging for an ultrafast light source
...ot droplets right through a pulsed beam of x-rays a billion times brighter than any ever created in a light source before.
ASU postdoc Dan DePonte did
most of the hard work and refinement needed to realize the design. It wasn't easy. Nozzles made of solid material like glass invariably clog up, limit...
Large trees declining in Yosemite
... generally resist fire more than small-diameter trees, so fewer large trees could also slow forest regeneration after fires.
"Although this study did
not investigate the causes of decline, climate change is a likely contributor to these events and should be taken into consideration," said USGS scien...
Organic food not nutritionally better than conventionally-produced food
...matic review of the available published literature on nutrient content of organic food ever conducted. The review focussed on nutritional content and did
not include a review of the content of contaminants or chemical residues in foods from different agricultural production regimens.
Over 50,000 pape...
Sex in the Caribbean: Environmental change drives evolutionary change -- eventually
...olony from which it cloned."
As predicted, clonal bryozoans rapidly disappeared from the record as the Caribbean was isolated. Species that survived did
so by becoming increasingly robust to reduce the chances of fragmentation while those that failed to evolve went extinct. They are still found in the...
1 in 6 health workers won't report in flu pandemic -- study by Ben-Gurion U. researchers
Personal safety assurances of workers can and should be provided as part of training. It is important to note that 24 percent of the respondents did
not perceive their work environment as safe, and 15 percent of the respondents felt they could not safely arrive to work.
Despite the growing re...
Placenta-derived stem cells may help sufferers of lung diseases
...lini, "provides convincing proof" that placenta-derived cells do confer benefits for bleomycin-induced lung injury. While the severity of inflammation did
not show an overall reduction, there was a marked reduction in neutrophil (white blood cell) infiltration after both xeno-and-allo-transplantation.
Smaller than expected, but severe, dead zone in Gulf of Mexico
... than forecasted, measuring 3,000 square miles. However the dead zone, which is usually limited to water just above the sea floor, was severe where it did
occur, extending closer to the water surface then in most years.
Earlier this summer, NOAA-sponsored forecast models developed by R. Eugene Turner...
Red List overlooks island species
...be under threat in the Canary Islands according to IUCN criteria. However, the lists of species threatened with extinction according to these criteria did
not coincide with reality, as they were "too extensive" and included species that "do not face any risk at all".
After analysing the basis for the ...
Protein that promotes cancer cell growth identified
...rchers also used immune-blot assays to demonstrate that reconstituting the Caspase-8 deficient cells with Caspase-8 with mutations in the RXDLL domain did
not result in EGF signaling. This suggests that Caspase-8 mediates signaling through the RXDLL domain. The scientists had previously shown in another ...
Short stressful events may improve working memory
...ne neuropathway was not blocked, performed better in the maze than the blocked group.
The researchers also determined that the stressful experience did
not increase depression or anxiety-related behavior in the animals.
"It is known that stress has both positive and negative actions in the brain, ...
New discovery suggests trees evolved camouflage defense against long extinct predator
... Chatham Islands, which are 800 kilometres east of New Zealand. Unlike New Zealand the islands lacked large browsers such as Moa and so the plant life did
not evolve a defence against them.
"The Chatham island species displays less morphological changes between adults and juveniles," said Burns. "If ...
Life on Earth came from other planets
...omly assembled in the methane sea."
Therefore, as only life can produce life, life on earth must have originated on other planets. But then, how did
it get here?
Most scientists believe all Earthly life descended from the first unicellular creatures that appeared on this planet. Based on an e...