Smithsonian scientists and colleagues report a new study that may shake up the way paleontologists think about how environmental change shapes life on Earth. The researchers summarized the environmental, ecological and evolutionary consequences for Caribbean shallow-water marine communities when the Isthmus of Panama was formed. They concluded that extinctions resulting when one ocean became two were delayed by 2 million years.

Researchers from the Smithsonian Tropical Research Institute, Scripps Institution of Oceanography and London's Natural History Museum report their study in the Proceedings of the National Academy of Sciences on March 12.

Perceived attractiveness is the result of compatibility of biological sex and gendered cues--masculinity and femininity as specified within the society—according to a study by researchers at New York University and Texas A & M University.

The University of Wisconsin School of Medicine and Public Health is among the first medical centers in the country taking part in a novel clinical trial investigating if a subject's own stem cells can treat a form of severe coronary artery disease.

The trial, just underway at UW Hospital and Clinics, is enrolling subjects in the Autologous Cellular Therapy CD34-Chronic Myocardial Ischemia (ACT34-CMI) Trial. The first patient underwent the procedure March 7. Because the study is randomized and "double-blinded," however, neither the patient nor the research physician knows if he received his own stem cells or a placebo substance.

This trial is the first human Phase II adult stem cell therapy study in the U.S.

Plant and animal diseases can play a major and poorly appreciated role in allowing the invasion of exotic species, which in turn often threatens biodiversity, ecological function and the world economy, researchers say in a new report.

In particular, a plant pathogen appears to have opened the gate for the successful invasion of non-native grasses into much of California, one of the world's largest documented cases of invading species and one that dramatically changed the history and ecology of a vast grassland ecosystem.

A new study by Christopher Plowe and colleagues (University of Maryland School of Medicine) on a malaria vaccine used at a testing site in Mali calls into question whether the best vaccine was chosen to be tested at this particular site.

The development of an effective malaria vaccine is not easy, in part because there are different strains of the Plasmodium parasite that causes the disease. The different strains carry different variants (alleles) of the genes encoding parasite components (antigens) used in test vaccines, which means that the parasites causing infection in a given location may differ from the ones used for vaccination. If this is the case, the immune response generated by the vaccine might be less effective or even ineffective.

Researchers at the Smithsonian Environmental Research Center report the results of a six-year experiment in which doubling the atmospheric greenhouse gas carbon dioxide (CO2) in a scrub oak ecosystem caused a reduction in carbon storage in the soil.

The scientists said this response suggests a limited capacity of Earth’s ecosystems to stabilize atmospheric CO2 and slow global warming. These findings add a new perspective and a measure of caution suggesting that elevated CO2, by altering microbial communities, may turn a potential carbon sink into a carbon source.

Previous studies have shown that plants will respond to higher CO2 by increasing growth and taking up much of the excess carbon.