Since the discovery of the charm quark in 1974, physicists have postulated a rare process in which a charm particle spontaneously changes into its antiparticle. Evidence for this behavior was uncovered three decades later by experiments in the US and Japan. However, conclusive observation did not emerge until this year from the CERN laboratory in Switzerland and Fermilab in the U.S. 

What is a charm quark? Protons and neutrons, the particles in an atomic nucleus, are made of smaller pieces called quarks and some types of quarks can form particles that exhibit surprising behaviors.

Women's perceptions of what is considered normal and desirable female genitalia may be influenced by exposure to modified images, according to psychologists writing in BJOG: An International Journal of Obstetrics and Gynaecology.

Requests for labiaplasty - reducing and making the labia minora symmetrical - have become a fad and are now the most widely performed female genital cosmetic procedure covered by Australian government health care over the past decade, increasing five-fold between 2001 and 2010. 

Species living together are not forced to evolve differently to avoid competing with each other, a notion that that has been debated since the early days of natural selection.

By focusing on ovenbirds, one of the most diverse bird families in the world, a team conducted the most in-depth analysis yet of the processes causing species differences to evolve. They found that although bird species occurring together were consistently more different than species living apart, this was simply an artifact of species being old by the time they meet. In fact, once variation in the age of species was accounted for, coexisting species were actually more similar than species evolving separately.

A new aquifer in the Greenland Ice Sheet holds liquid water all year long in the otherwise perpetually frozen winter landscape. And it's big - 27,000 square miles. 

The reservoir is a "perennial firn aquifer" because water persists within the firn; layers of snow and ice that don't melt for at least one season. Researchers believe it figures significantly in understanding the contribution of snowmelt and ice melt to sea levels.  The Greenland Ice Sheet is vast, covering roughly the same area as the states of California, Nevada, Arizona, New Mexico, Colorado and Utah combined. The average thickness of the ice is 5,000 feet.  

Cranial surgery is tricky business today. Patients will need an aseptic environment, specialized surgical instruments and copious amounts of pain medication both during and afterward.

In ancient Peru, trepanation  - removing a section of the cranial vault using a hand drill or a scraping tool - was a lot more dangerous, and yet more common. They used it to treat a variety of ailments, from head injuries to heartsickness. 

Excavating burial caves in the south-central Andean province of Andahuaylas in Peru, U.C. Santa Barbara archaeologist Danielle Kurin and colleagues unearthed the remains of 32 individuals that date back to the Late Intermediate Period (ca. AD 1000-1250). Among them, 45 separate trepanation procedures were in evidence. 

Caterpillars of two species of butterflies in Colorado and California aren't waiting for China and India to stop belching out so much CO2 - according to a paper in the journal Functional Ecology, they have already evolved to feed rapidly at higher and at a broader range of temperatures, just in the last 40 years, suggesting to the biologists that they did so in order to quickly to cope with a hotter, more variable climate. 

This represents the first instance where recent climate change has affected physiological traits, such as the internal workings of how the body regulates feeding behavior, said Professor Joel Kingsolver at the University of North Carolina at Chapel Hill.

A paper in the International Journal of Obesity has found that even weight loss can be discriminatory;  African-American women may need to eat less or exercise more than European-American women to lose the same amount of weight.

Some studies have suggested that women of color don't lose as much weight as white women even in response to the same behavioral interventions of calorie restriction or increased physical activity.