It's hardly surprising that clinically depressed people act differently than healthy people. Quantifying the difference, however, can be difficult. Now a collaboration of physicists and psychiatrists in Japan has found a way to clearly and objectively measure depression.

The researchers outfitted both healthy control subjects and depressed patients with accelerometers to continuously measure their motions over 5-day periods. Although activity levels in all of the subjects followed power-law patterns (a type of distribution that often turns up in physics studies of natural systems) the activity levels of depressed patients were clearly distinguished from healthy subjects by a number known as the scaling parameter.

While we are a long way off from the lightweight, high-performance, magical cloak of Harry Potter, physicists have been busy designing ways to make invisibility possible.

A recent theoretical analysis of a column-shaped invisibility cloak, by a collaboration of researchers from Sweden and China, showed that a cloak made to ideal specifications could render an object (or wizard) hidden inside perfectly invisible. However, even slight deviations from these specifications will cause the invisibility to break down.

The researchers analyzed the properties of a simulated tube of special metamaterials (manmade materials with intricate, microscopic structures) that can force light to follow a specified path.

Several genes with strong associations to schizophrenia have evolved rapidly due to selection during human evolution, according to researchers who found a higher prevalence of the influence of so-called positive selection on genes or gene regions known to be associated with the disorder than a comparable control set of non-associated genes, functioning in similar neuronal processes.

This is consistent with the theory that positive selection may play a role in the persistence of schizophrenia at a frequency of one per cent in human populations around the world, despite its strong effects on reproductive fitness and its high heritability from generation-to-generation.

It also provides genetic evidence consistent with the long-standing theory that schizophrenia represents, in part, a ma

According to new research at the University of Virginia Health System, N-acetylcysteine (NAC), an anti-oxidant commonly used in nutritional and body-building supplements, can form a red blood cell-derived molecule that makes blood vessels think they are not getting enough oxygen. This leads to pulmonary arterial hypertension (PAH), a serious condition characterized by high blood pressure in the arteries that carry blood to the lungs.

“NAC fools the body into thinking that it has an oxygen shortage,” said Dr. Ben Gaston, UVa Children’s Hospital pediatrician and researcher who led the study. “We found that an NAC product formed by red blood cells, know as a nitrosothiol, bypasses the normal regulation of oxygen sensing.

An 80-million-year-old dinosaur fossil unearthed in the Gobi Desert of Mongolia demonstrates that miniaturization, long thought to be a hallmark of bird origins and a necessary precursor of flight, occurred progressively in primitive dinosaurs.

The find, described in the September 7 issue of the journal Science, is made up of the fossilized bones of a new dinosaur the researchers have named Mahakala, and includes portions of its skull, forelimb and hindlimb, as well as much of the vertebral column.

Mahakala is an early evolutionary offshoot of the group of carnivorous dinosaurs known as dromaeosaurids that also includes the agile, sickle-clawed Velociraptor made famous in the 1993 movie Jurassic Park.

Bog mummies are 2000-year-old mummies from the Iron Age that were preserved with amazing detail by the peat bogs of Europe.

Physical anthropologists draw conclusions from the eerily preserved hair, leathery skin and other features in the mummies that emerge from the bogs. In the Iron Age, from approximately 500BC to 500AD, people were often cremated, leading experts to believe that mummies preserved by the bogs were usually those who met their demise through particularly violent means or were used as sacrifices.