A general mathematical theory that predicts how cracks spread through materials like glass and ice can also predict the direction in which rivers will grow, according to a new MIT study.

In fracture mechanics, the theory of local symmetry predicts that, for example, a crack in a wall will grow in a direction in which the surrounding stress is symmetric around the crack's tip.

Scientists at MIT have now applied this theory to the growth of river networks, finding that as a river fed by groundwater cuts through a landscape, it will flow in a direction that maintains symmetric pressure from groundwater around the river's head.

EEAST LANSING, Mich. - Stealthy diseases sometimes trick plants by hijacking their defense signaling system, which issues an alarm that diverts plant resources for the wrong attack and allows the enemy pathogens to easily overrun plants.

A team of international scientists led by Michigan State University, however, is helping plants counter these attacks by boosting plants' alert system. New research in the current issue of Proceedings of the National Academy of Sciences shows that the team has engineered the receptor for jasmonate, a plant hormone that plays a central role in plant defense, to fend off such stealthy attacks from highly evolved pathogens.

The Cascadia subduction zone (CSZ) has captured major attention from paleoseismologists due to evidence from several large (magnitude 8-9) earthquakes preserved in coastal salt marshes. Stratigraphic records are proving to be useful for learning about the CSZ's past, and microfossils may provide more answers about large ancient earthquakes.

They may also allow modelers to learn more about potential major hazards related to earthquakes in the area, which would contribute to public preparedness for such events.

The latest Ebola virus outbreak in West Africa also took its toll socially on one of the fastest growing populations in the United States - African immigrants.

Guy-Lucien Whembolua, a University of Cincinnati assistant professor of Africana studies, reviewed reports in mainstream U.S. media related to African immigrants and the Ebola Virus Disease (EVD). The search turned up 21 news articles that matched the criteria for the study - articles focusing on African immigrants in the U.S. and the Ebola virus.

By licking a wound it heals faster -- this is not simply popular belief, but scientifically proven. Our saliva consists of water and mucus, among other things, and the mucus plays an important role. It stimulates white blood cells to build a good defense against invaders, according to a group of researchers at Lund University in Sweden together with colleagues from Copenhagen and Odense in Denmark.

"White blood cells are among other places located in the oral mucosa, and they represent the body's first line of defence against infectious agents. The mucus in the mouth causes the white blood cells to throw out a 'net' that traps bacteria", explains Ole Sørensen from the Division of Infection Medicine.

A Newcastle University study has shown that baby birds that have a difficult start in life grow to be fatter and greedier than their more fortunate siblings.

The researchers, led by Professor Melissa Bateson and Dr Clare Andrews, discovered that stress and difficulties as a chick made a long lasting impression on a starling's relationship with food.

The study, published today in the journal Animal Behaviour and funded by the BBSRC, showed that the smallest chicks in European starling families changed their adult feeding behaviour, resulting in a fatter body composition in the fully developed birds.

A paper published earlier this year claiming chimpanzees can learn each others' language is not supported by others who looked at the work. The paper published in Current Biology in February centered on the examination of two sets of chimpanzees in the Edinburgh Zoo: one that had been captive for several years in the facility and one that had recently arrived from the Beekse Bergen Safari Park in the Netherlands.

Over a three-year period, the researchers claimed that the latter set had altered their sounds to those of the former set when communicating about a common object, apples, resulting in what they saw as a newly shared vocalization. 

Researchers have set out to solve the mystery of a degenerative sign of aging in concrete: the alkali-aggregate reaction (AAR), where a material forms that takes up more space than the original concrete and thus gradually cracks the concrete from within as the decades go by.

The researchers have now explored the exact structure of this material. They managed to demonstrate that its atoms are arranged extremely regularly, making it a crystal. They also showed that the structure of this crystal is a so-called sheet-silicate structure. This specific structure had never been observed before. 

A global problem

Colorectal cancer cells with certain mutations "handle" vitamin C differently than other cells, and this difference ultimately kills them, finds a new study.

The idea that vitamin C could be an effective therapy for human cancer holds great appeal, but its track record in this arena has been more claim than data, with most clinical studies finding no evidence. Several ongoing clinical studies are exploring whether a therapeutic effect may require a high plasma level of vitamin C that can be achieved only by intravenous, not oral, administration.

In the meantime, the molecular mechanism by which vitamin C might selectively kill cancer cells remains unclear.

Let's declare Pluto as a dwarf or sub dwarf planet AND a planet! This is about the vexed question of whether Pluto is a planet or not. Yes the International Astronomical Union "settled the question" but I'm not sure their decision is one that will work all the way into the future, for instance if we find Earth or Neptune sized objects beyond Pluto. And it also stretches language in an awkward way to say that Pluto is a dwarf planet but not a planet - and the English word "dwarf" seems to have little to do with the concept of clearing your neighbourhood.