By measuring a peak in the temperature of hot gas in the center of the giant elliptical galaxy NGC 4649, scientists have determined the mass of the galaxy's supermassive black hole. The method, applied for the first time, gives results that are consistent with a traditional technique.

Astronomers have been seeking different, independent ways of precisely weighing the largest supermassive black holes, that is, those that are billions of times more massive than the sun. Until now, methods based on observing the motions of stars or of gas in a disk near such large black holes had been used.

"This is tremendously important work since black holes can be elusive, and there are only a couple of ways to weigh them accurately," said Philip Humphrey, leader of the study and an assistant project scientist in the Department of Physics and Astronomy at UCI. David Buote, associate professor of physics and astronomy at UCI, also worked on this study.

Women exposed to high levels of PCBs (polychlorinated biphenyls – a group of banned environmental pollutants) are less likely to give birth to male children, according to a study published today in Environmental Health.

The researchers found that among women from the San Francisco Bay Area, those exposed to higher levels of PCBs during the 50s and 60s, were significantly more likely to give birth to female children.

Similar exposure is thought to have occurred in Wales, after a quarry on the edge of Groesfaen village near Cardiff was used as a toxic dumping ground from 1965 to 1972.

A two-year study led by researchers from Ben-Gurion University of the Negev (BGU) reveals that low-carbohydrate and Mediterranean diets may be just as safe and effective in achieving weight loss as the standard, medically prescribed low-fat diet, according to a new study published in the prestigious New England Journal of Medicine.

In the study, 322 moderately obese people were intensively monitored and were randomly assigned one of three diets: a low-fat, calorie-restricted diet; a Mediterranean calorie-restricted diet with the highest level of dietary fiber and monounsaturated/saturated fat; or a low-carbohydrate diet with the least amount of carbohydrates, highest fat, protein, and dietary cholesterol. The low-carb dieters had no caloric intake restrictions.

It's no secret that the Commonwealth Fund doesn't like private health care and their new national scorecard states that scores on access have declined significantly since the first national scorecard in 2006. Despite spending more on health care than any other industrialized nation, they state, the U.S. overall continues to fall far short on key indicators of health outcomes and quality, with particularly low scores on efficiency.

The Tunguska event is regarded as one of the biggest natural disasters of modern times. On 30 June 1908 one or more explosions took place in the area close to the Tunguska River north of Lake Baikal. The explosion(s) flattened around 80 million trees over an area of more than 2000 square kilometres.

The strength of the explosion is estimated to have been equivalent to between five and 30 megatons of TNT. That is more than a thousand times as powerful as the Hiroshima bomb.

This almost unpopulated region of Siberia was first studied in 1927 by Professor Leonid A. Kulik. There are a number of different theories about what caused the catastrophe. However, the majority of scientists assume that it was caused by a cosmic event, such as the impact of a meteorite, asteroid or comet. If it had exploded in the atmosphere just under five hours later, St. Petersburg, which was the capital of Russia at that time, would have been completely destroyed because of the Earth's rotation.

hominin fossils are the most important materials for exploring human origins and evolution. Since most hominin fossils are incomplete, or filled with a heavy calcified matrix, it is difficult or often impossible to reconstruct the endocast in a real fossil without destroying it.

Accordingly, traditional methods limited the study of human brain evolution. CT can explore fossils in a noninvasive way by transforming a real fossil into a virtual object, and make it possible for paleoanthropologists to extend the study of fossil specimens from the exterior to the interior.