The origins of modern humans continues to be one of the most hotly debated topics among anthropologists, and there is little consensus about where and when the first members of our species, Homo sapiens, became fully modern. While fossil evidence tells a complex tale of mosaic change during the African Stone Age, almost nothing is known about changes in human 'life history,' or the timing of development, reproductive scheduling, and lifespan. Research during the past two decades has shown that early fossil humans (australopithecines and early Homo) possessed short growth periods, which were more similar to chimpanzees than to living humans.

Although scientists know about basic voice production—the two "vocal folds" in the larynx vibrate and pulsate airflow from the lungs—the larynx is one of the body's least understood organs.

Sound produced by vocal-fold vibration has been extensively researched, but the specifics of how airflow actually affects sound have not been shown using an animal model—until now.

Vortices, or areas of rotational motion that look like smoke rings, produce sound in jet engines. New research from the University of Cincinnati (UC) uses methods developed from the study of jet noise to identify similar vortices in an animal model.

Unlike most of our sensory systems that detect only one type of stimuli, our sense of smell works double duty, detecting both chemical and mechanical stimuli to improve how we smell, according to University of Pennsylvania School of Medicine researchers in the March issue of Nature Neuroscience.

This finding, plus the fact that both types of stimuli produce reaction in olfactory nerve cells, which control how our brain perceives what we smell, explains why we sniff to smell something, and why our sense of smell is synchronized with inhaling.

With hundreds of nanotechnology-enabled products already on the market and many more in the commercial pipeline, a new report by a former senior Environmental Protection Agency (EPA) official urges policymakers to give greater attention to the challenges of crafting an oversight system that can effectively address health and safety issues particular to nanoscale materials and devices.

"It is time for government, industry, the scientific community, non-governmental organizations and other interested parties to begin a more systematic discussion about the core elements of an oversight framework for nanoscale materials" writes Mark Greenwood in Thinking Big About Things Small: Creating an Effective Oversight System for Nanotechnology. Greenwood worked for EPA for over 16 years and was director of EPA's Office of Pollution Prevention and Toxics from 1990 to 1994.

Researchers at the University of Illinois have found that adolescence is a time of remodeling in the prefrontal cortex, a brain structure dedicated to higher functions such as planning and social behaviors.

The study of rats found that both males and females lose neurons in the ventral prefrontal cortex between adolescence and adulthood, with females losing about 13 percent more neurons in this brain region than males.

Assigning dates to the events in the life of a rock—for example, a collision with a piece of continent, or a journey through the Earth’s crust—has long challenged geologists, as the events themselves can confound evidence of the past.

But now, armed with a custom-built machine known as the Ultrachron, University of Massachusetts Amherst scientists are refining a technique that allows them to pin dates to geologic processes with unprecedented precision.