Bacteria must talk to each other, in a sense. They use signals to inform neighbors whether to switch certain genes on or off and this allows them to adapt to changing circumstances.

What exactly do bacteria learn from the signal substances between them? There have been two theories: the release of signal substances is understood to be either a cooperative strategy to determine the cell density (quorum sensing) or – alternatively – a non-cooperative strategy in which the signal substance is only used to determine the dimensions of the space surrounding the cell (diffusion sensing). However, both theories have not been shown to work under natural conditions, which usually are much more complex than those in laboratory.

Intimidation and threats are common throughout society, whether it’s in the school playground, sporting arena or boardroom. Threatening behaviour is equally widespread among non-human animals.

Individuals signal their superior strength to competitors to obtain food, resolve territorial disputes and acquire mates. Current theory insists that signals of strength should be honest. Surprisingly researchers have found that dishonest signals are used routinely during dominance disputes by male Australian crayfish.

Scientists at the University of Nevada, Reno are at the forefront on a number of seismological fields, including helping the world better determine whether an earthquake is big enough to generate an ocean-wide tsunami.

Through work at the Nevada Seismological Laboratory on the Nevada campus, important data on seismological events throughout the world is compiled, including Monday’s fatal occurrence in the Solomon Islands, where at least 13 people were killed. Tsunamis triggered by an undersea earthquake crashed ashore and wiped away entire villages and set off alerts from Australia to Hawaii.

In the event of a nuclear or radiological catastrophe -- such as a nuclear accident or a “dirty bomb” -- thousands of people would be exposed to radiation, with no way of quickly determining how much of the deadly substance has seeped inside their bodies. Scientists at Duke University Medical Center have developed a new blood test to rapidly detect levels of radiation exposure so that potentially life-saving treatments could be administered to the people who need them most.

There appears to be a critical window of 48 to 72 hours for administering treatments aimed at halting the devastating effects of radiation, said senior study investigator John Chute, M.D., an associate professor of medicine in the Duke Adult Bone Marrow and Stem Cell Transplant Program.

A new study coordinated by the New York-based Wildlife Conservation Society and other groups found that Central Africa’s increasing network of roads – which are penetrating deeper and deeper into the wildest areas of the Congo Basin – are becoming highways of death for the little known forest elephant. The study, which appears in the journal Public Library of Science, concludes that forest elephants are severely impacted by ivory poachers who use roads to gain access into their remote jungle home. In addition, roads serve as conduits of advancing human settlement fragmenting previously intact forests where elephants live.

Cartilaginous fishes (sharks, rays, skates, and chimaeras) are the phylogenetically oldest group of living jawed vertebrates. They are also an important outgroup for understanding the evolution of bony vertebrates such as human and teleost fishes. In a new study published online this week in the open access journal PLoS Biology, Byrappa Venkatesh, Sydney Brenner, and colleagues performed survey sequencing (1.4× coverage) of a chimaera, the elephant shark (Callorhinchus milii).