New research indicates that hormonal intrauterine devices (IUDs) and contraceptive implants remain highly effective one year beyond their approved duration of use, according to a study at Washington University School of Medicine in St. Louis.

The preliminary findings are reported online Feb. 5 in Obstetrics & Gynecology and will appear in the journal's March 15 print edition.

The researchers are evaluating whether such long-acting forms of birth control are effective for up to three years past their recommended length of use as approved by the Food and Drug Administration (FDA). Contraceptive implants -- matchstick-sized rods inserted into the arm -- are approved for three years, and hormonal IUDs are approved for five years.

A team has undertaken what they call the most comprehensive examination of skyglow -  variations in the radiance of the night sky - ever done and found remarkably large variations in artificial night sky brightness at the different observation sites.  

Light became popular because it allowed us to extend the day - and electricity meant people could read a book without falling asleep and setting themselves on fire. But the introduction of light into the nighttime environment is one of the most striking changes humans have made to the Earth’s physical environment, and it is associated with several unintended negative consequences. One example is skyglow, the artificial brightening of the night sky.

The gender stereotype is that women want commitment and men want sex - but a study of the Makushi people in Guyana upends that, finding that men more likely to seek long-term relationships. Why? Because women are in short supply so a lack of commitment is a romantic negative. Some villages in Guyana are the opposite of New York City, where you could have sex with a different person every day for 5,000 years and never duplicate.

Also debunked is the conventional view that when men outnumber women, there are more likely to be male-male fights and increases in sexually transmitted diseases.

A cancer false alarm could put people off checking out cancer symptoms they develop in the future, according to a review of papers.

More than 80 percent of patients with potential cancer symptoms are given the all-clear after investigations. But according to the new paper, having a false alarm might discourage people from seeking help, even years later, if they notice possible symptoms of the disease again.

A new study links a well-known cell communication pathway called Notch to one of the most common -- but overall still rare -- brain tumors found in children.

Researchers have uncovered a pathway that's key for protecting healthy tissue from overly active immune responses. The findings, which are described in an upcoming issue of the Journal of the American Society of Nephrology, may help clinicians provide better treatments for patients with a variety of autoimmune diseases.

During inflammatory responses due to infection, trauma, or cancer, the body's immune system becomes highly activated in an attempt to fend off invading organisms, foreign bodies, or tumor cells. Excessive immune activation, however, often results in collateral damage to surrounding healthy tissues. Even worse, uncontrolled immune responses can lead to the development of self-destructive autoimmune diseases.