A powerful collision of galaxy clusters has been captured with NASA's Chandra X-ray Observatory and Hubble Space Telescope. Like its famous cousin, the so-called Bullet Cluster, this clash of clusters provides striking evidence for dark matter and insight into its properties.

Like the Bullet Cluster, this newly studied cluster, officially known as MACSJ0025.4-1222, shows a clear separation between dark and ordinary matter. This helps answer a crucial question about whether dark matter interacts with itself in ways other than via gravitational forces.

There is a great deal of concern about the effects of global warming on the Greenland ice sheet but scientists at the University of Bristol and the University of Leeds have taken the discussion to a deeper level - namely in stating that only changes in atmospheric carbon dioxide are able to explain the transition from the mostly ice-free Greenland of three million years ago to the ice-covered Greenland of today.

CO2 drops caused Greenland to become ice-covered so CO2 gains could undo that, they say.

There are several competing theories, ranging from changes in ocean circulation, the increasing height of the Rocky Mountains, changes in the Earth's orbit, and natural changes in atmospheric greenhouse gas concentrations. Using state-of-the-art computer climate and ice-sheet models, Dr. Dan Lunt from the University of Bristol and colleagues decided to test which, if any, of these theories was the most credible.

Not all fat is created equal, it seems. A Temple University study finds fat in obese patients is "sick" when compared to fat in lean patients.

Why 'sick? When our bodies don't work properly, we say we're sick. The study in the September issue of Diabetes finds that the same could be said for fat tissue found in obese patients. The cells in their fat tissue aren't working properly and as a result, are sicker than cells found in lean patients' fat tissue.

Lead author Guenther Boden, M.D. theorizes that "sick fat" could more fully explain the link between obesity and higher risk of diabetes, heart disease and stroke.

The latest research into dual-purpose contraceptives and non-hormonal contraception will be presented at the annual scientific conference of the Society for Reproductive Biology (SRB) conference in Melbourne.

University of Newcastle Laureate professor John Aitken, a world-leader in reproductive biology, will discuss the need to develop novel, safe, effective, dual-purpose contraceptive agents that combine the prevention of pregnancy with protection against sexually transmitted diseases (STDs). His research has explored the development of a contraceptive agent that immobilises – but does not kill – sperm. The agent also possesses microbicidal activity simultaneously reducing the risk of infection with sexually transmitted diseases, such as Chlamydia.

'Framing the debate' had its 15 minutes of fame, somewhere early in 2006, and since then has been revealed as little more than another word for 'spin' and, in a new study published in the journal Communication, Culture & Critique, Barbara Barnett of Kansas University lays out how framing was used in the Duke lacrosse players rape allegation.

Despite investments, community goodwill and some good ideas, a vexing question remains in the age of school reform: Why has so much hope and effort led to disappointment?

Beginning in the late 1980s, the Chicago Public Schools, like many urban schools systems, launched a series of initiatives to reorganize schools, improve teaching and encourage parental participation. The changes in Chicago not always have met the expectations of proponents, wrote Charles Payne in his new book, "So Much Reform, So Little Change: The Persistence of Failure in Urban Schools".

The results of national school reform efforts also have led to some disappointment. A lack of trust among teachers and principals and parents frequently creates dysfunction in schools, noted Payne.