Scientists have developed a new method to model heat wave magnitude that takes both the duration and the intensity of the heat wave into account.

The new metric--the Heat Wave Magnitude Index daily (HWMId)--indicates that a little-studied heat wave in Finland in 1972 had the same extent and magnitude of the 2003 European heat wave that is considered the second strongest heat wave since 1950.

The findings are published today, 27th November 2015, in the journal Environmental Research Letters.

New research finds that progesterone supplements in the first trimester of pregnancy do not improve outcomes in women with a history of unexplained recurrent miscarriages.

The study of 826 women with previously unexplained recurrent miscarriage showed that those who received progesterone treatment in early pregnancy were no less likely to miscarry than those who received a placebo. This was true whatever their age, ethnicity, medical history and pregnancy history.

Smoking high potency 'skunk-like' cannabis can damage a crucial part of the brain responsible for communication between the two brain hemispheres, according to a new study.

Researchers have known for some time that long-term cannabis use increases the risk of psychosis and recent evidence suggests that alterations in brain function and structure may be responsible for this greater vulnerability. 

Two new studies report dramatic changes in phytoplankton abundance and nature, changes that have important implications for storing excess carbon. Collectively, these studies suggest that certain types of carbon-intensive algae are flourishing and will play increasingly prominent roles as carbon pumps, removing carbon dioxide from the atmosphere. Using the isotopic signature of phytoplankton amino acids embedded in skeletons of deep water soft corals, Kelton McMahon and colleagues determined how plankton dominance changed in the North Pacific over the past millennium. Their analysis reveals that there was a transition from dominance by non-nitrogen-fixing cyanobacteria to that by eukaryotic microalgae.

Cognitive behavioural therapy could help many people with a dental phobia overcome their fear of visiting the dentist and enable them to receive dental treatment without the need to be sedated, according to a new study by King's College London.

Anxiety about visiting the dentist is common and becomes a phobia when it has a marked impact on someone's well-being; people with dental phobias typically avoid going to the dentist and end up experiencing more dental pain, poorer oral health and a detrimental effect on their quality of life. Estimates from the most recent Adult Dental Health Survey in the UK suggest around one in ten people suffers from dental phobia.

A James Cook University scientist says a new study shows more than half of all tree species in the world's most diverse forest -- the Amazon -- may be globally threatened.

Long-time Amazon researcher, Professor William Laurance from JCU, is a co-author of the study, published this week in the journal Science Advances.

It compared data from forest surveys across the Amazon with maps of current and projected deforestation to estimate how many tree species have been lost, and where.

Professor Laurance said the study suggests existing Amazonian parks and reserves, if properly managed, could protect many of the threatened species. But it was not a forgone conclusion.