One of astronomy's big questions is why galaxies forming as recently as 1 billion years after the Big Bang contain so much dust. The leading hypothesis is that supernovae, stars that explode at the end of their lives, contain large amounts of metal-enriched material that, in turn, harbors key ingredients of dust, like silicon, iron and carbon.
LIVERMORE, Calif. -- By using the amount of carbon 14 in the atmosphere from above-ground nuclear testing in the 1950s and 1960, researchers have determined that cells in the human heart develop into adulthood.
But as humans age, the percentage of new heart cells decreases markedly. By age 25, renewal of heart cells gradually decrease from 1 percent turning over annually to .45 percent by the age of 75. About 50 percent of the heart cells a human is born with will regenerate during a lifetime.
Myocardial damage often results in chronic heart failure because of the loss and insufficient regeneration of heart cells. But this new finding may mean that patients, who have suffered myocardial damage as a result of a heart attack, may have some good news.
(PHILADELPHIA) – A new federally funded University of Pennsylvania School of Medicine study aims to learn whether women at high risk of breast cancer can use exercise to meaningfully reduce their risk of getting the disease. Building on evidence that reducing estrogen in the body reduces cancer risk, and that elite female athletes experience a drop in estrogen levels that often cause them to stop ovulating and menstruating, the WISER Sister trial will investigate two different levels of regular treadmill exercise as a possible intervention for breast cancer risk reduction.
(Boston) -- A study of a Big Brothers Big Sisters of America formal mentoring program, which matched adolescent girls with women mentors, revealed that strong emotional support and improvement in girls psychosocial functioning from these relationships was a dominant theme coupled with the development of new skills and confidence through collaborations.
Unlike previous mentoring studies, this one explicitly examined the relational processes in adolescent girls' relationship with female adult mentors from the perspective of the participants themselves. Each adolescent and mentor pair was extensively interviewed separately and then together. Their recorded comments were analyzed and revealed that girls benefit from both skill development and gain vital emotional support.
In 2008, residents of Hispaniola experienced one of their worst hurricane seasons in recent memory. Hispaniola, the Caribbean island containing Haiti and the Dominican Republic, is located directly within the hurricane belt, and was pummeled by five tropical cyclones last year: Fay, Gustav, Hanna, Ike, and low over the Dominican Republic on Sept. 24 what would become Kyle after moving north. More than 800 people were reported dead or missing from these storms.
Haiti occupies the western third of Hispaniola, while the Dominican Republic covers the eastern two-thirds. Hispaniola is the second-largest and most populated island of the Antilles. It's located between Cuba to its west, and Puerto Rico to its east.
AUGUSTA, Ga. – Dental amalgam has been proven safe and effective for years, yet unfounded controversy still surrounds it, a Medical College of Georgia researcher says.
Dentists have used amalgam, an alloy of mercury with at least one other metal, in fillings for over 200 years. Amalgam fillings don't contain enough mercury to cause potential health problems associated with larger doses, says Dr. Rod Mackert, professor of dental materials in the MCG School of Dentistry Department of Oral Rehabilitation.
DALLAS – April 2, 2009 – Researchers at UT Southwestern Medical Center have shed light on how the neurotransmitter dopamine helps brain cells process important information.
Researchers found in a study of mouse cells that this neurotransmitter, one of the molecules used by nerve cells to communicate with one another, causes certain brain cells to become more flexible and changes brain-cell circuitry to process important information differently than mundane information.
The New York Yankees, Boston Red Sox, Cleveland Indians and Los Angeles Angels should make the playoffs in the American League (AL) in 2009 with most other teams lagging well behind. The National League (NL) should see another very tight race in the Eastern Division as has occurred in recent years.
However, this year it looks like there may be a three-way tie among the defending World Series Champion Philadelphia Phillies, the Atlanta Braves, and the New York Mets,. Two of these teams should make the playoffs (one as Eastern Division champion and the other as NL wild card team) while the Chicago Cubs and Los Angeles Dodgers should handily win their divisions, said Bruce Bukiet.
WEST LAFAYETTE, Ind. - Researchers have developed a critical part of a hydrogen storage system for cars that makes it possible to fill up a vehicle's fuel tank within five minutes with enough hydrogen to drive 300 miles.
The system uses a fine powder called metal hydride to absorb hydrogen gas. The researchers have created the system's heat exchanger, which circulates coolant through tubes and uses fins to remove heat generated as the hydrogen is absorbed by the powder.
Summers in the Arctic may be ice-free in as few as 30 years, not at the end of the century as previously expected. The updated forecast is the result of a new analysis of computer models coupled with the most recent summer ice measurements.
"The Arctic is changing faster than anticipated," said James Overland, an oceanographer at NOAA's Pacific Marine Environmental Laboratory and co-author of the study, which will appear April 3 in Geophysical Research Letters. "It's a combination of natural variability, along with warmer air and sea conditions caused by increased greenhouse gases."
Since the days of Charles Darwin, researchers are interested in reconstructing the "Tree of Life", and in understanding the development of animal and plant species during their evolutionary history. In the case of vertebrates, this research has already come quite a long way. But there is still much debate about the relationships between the animal groups that made their apparation very early in evolutionary history, probably in the late Precambrian, some 650� million years ago.
Van Bael and colleagues used laboratory colonies of one leaf cutter ant species, Atta colombica, to test the ants' response to leaves from a tropical vine, Merremia umbellata, in which they had experimentally manipulated the densities of one fungal endophyte species, Glomerella cingulata, in order to present the ants with leaves containing either high or low levels of fungus. They also pitted 32 additional endophytic fungal strains against cultures of the garden cultivar in Petri plates to find out if they would restrict each others' growth.
CAMBRIDGE, Mass. (April 2, 2009) – Whitehead Institute researchers have quintupled the number of identifiable prion proteins in yeast and have further clarified the role prions play in the inheritance of both beneficial and detrimental traits.
"The big debate in the field is are the prions functional – are they evolved to be prions, or are they always a disease, as in "mad cow'" disease in mammals," says Randal Halfmann, a research assistant in Whitehead Member Susan Lindquist's lab, and coauthor of the paper featured on the cover of the April 3 issue of the journal Cell. "We wanted to find more prions and see what they're doing, so we could answer that question."
