Invasive pests known as spruce bark beetles have been attacking Alaskan forests for decades, killing more than 1 million acres of forest on the Kenai Peninsula in southern Alaska for more than 25 years.

Beyond environmental concerns regarding the millions of "beetle kill" dead trees, inhabitants of the peninsula and surrounding areas are faced with problems including dangerous falling trees, high wildfire risks, loss of scenic views and increased soil erosion. Intriguingly, a sociologist from the University of Missouri says that human perception of the beetle kill problem in the Kenai Peninsula has improved over time, despite little improvement in the environmental conditions.

A study of approximately 95,000 children with older siblings found that the measles-mumps-rubella (MMR) vaccine is not associated with an increased risk of autism spectrum disorders regardless of whether older siblings had been diagnosed on the autism spectrum - and epidemiological papers say those children should be at higher risk for an autism diagnosis.

During the last 15 years, no valid study has found a link between the MMR vaccine and ASD but some parents and people selling alternative medicines continue to associate the vaccine with ASD. Surveys of parents who have children with ASD suggest that many believe the MMR vaccine was a contributing cause.

Heavy snoring and sleep apnea may be linked to memory and thinking decline at an earlier age, according to a new study - but treating the disorders with a breathing machine may delay the decline. 

For the study, the medical histories for 2,470 people ages 55 to 90 were reviewed. Participants were categorized as either free of memory and thinking problems, in early stages of mild cognitive impairment (MCI), or with Alzheimer's disease. The researchers also looked at people with untreated sleep breathing problems versus those without the sleep breathing problems and also untreated versus treated people with sleep breathing problems.

Teachers are likely to interpret students' misbehavior differently depending on the student's race, according to a new paper. 

Racial differences in school discipline are widely known, and black students across the United States are more than three times as likely as their white peers to be suspended or expelled, according to the background information, but the psychological processes that contribute to those differences have not been clear.

"The fact that black children are disproportionately disciplined in school is beyond dispute," said Stanford psychology Professor Jennifer Eberhardt in an interview. "What is less clear is why."

A new analysis of 1,000 years of temperature records suggests global warming is not progressing as fast as it was projected under the most severe emissions scenarios outlined by the Intergovernmental Panel on Climate Change (IPCC). 

Natural variability in surface temperatures - caused by interactions between the ocean and atmosphere, and other natural factors - can account for observed changes in the recent rates of warming from decade to decade and these "climate wiggles" can slow or speed the rate of warming from decade to decade, or accentuate or offset the effects of increases in greenhouse gas concentrations.

A number of studies have shown that coffee helps to protect against breast cancer and new work led by Lund University has found that it also inhibits the growth of tumors and reduces risk of recurrence in women who have been treated with the drug tamoxifen.

In the cell study, the researchers looked more closely at two substances that usually occur in the coffee drunk in Sweden – caffeine and caffeic acid - and is a follow-up of the results the researchers obtained two years ago.