Commonly used by around 10 million people in east Africa and countries in the Arabian peninsula, chewing khat for its stimulant properties has also become popular in the UK among immigrants of the Somali, Yemeni and Ethiopian communities. Whilst it is reported to have cultural functions, it is also increasingly reported to be associated with social and medical problems including anti-social behaviour, unemployment, psychoses, depression, and self-neglect.

The Huygens Atmosphere Structure Instrument (HASI) scored a first in 2005 by measuring the electrical conductivity of Titan’s atmosphere. The results hint at a new way to investigate the subsurface layers of Titan and could provide insight into whether or not Titan has a subsurface ocean.

The Permittivity, Waves and Altimetry (PWA) sensor on Huygens detected an extremely low frequency (ELF) radio wave during the descent. It was oscillating very slowly for a radio wave, just 36 times a second, and increased slightly in frequency as the probe reached lower altitudes.

Discarded crab and lobster shells may be the key to prolonging the life of microbial fuel cells that power sensors beneath the sea, according to a team of Penn State researchers.

To produce energy, microbial fuel cells need organic material for the microbes to consume. However, deep sea sediments can be surprisingly devoid of organic material because living things in the photic zone – the area where light penetrates the water – are continuously recycled and little falls to the ocean floor. An absence of organics limits the lifetime of marine microbial fuel cells.

The ability to learn from experience is of central importance to human existence. It allows us to acquire many of the skills we need to complete a wide variety of complicated, multi-step tasks in an efficient manner. It also creates habit – a critical, if often overlooked factor in the product and service choices consumers make. An important new study from the Journal of Consumer Research demonstrates how this “cognitive lock-in” can cause us to remain loyal to a product, even if objectively better alternatives exist.

“We find that consumers typically are not aware that this mechanism is a powerful determinant of the choices they make,” write Kyle B.

Scientists exploring the remote highlands of eastern Suriname discovered 24 species believed to be new to science, including an Atelopus frog with brilliant purple markings, four Eleutherodactylus frog species, six species of fish, 12 dung beetles and an ant species.

The scientists also found 27 species endemic to the Guayana Shield region comprising Suriname and neighboring Guyana, French Guiana and northern Brazil, including a rare armored catfish, Harttiella crassicauda, feared extinct because gold mining activities had contaminated a creek where it was last seen more than 50 years ago.

Technically advanced molecular imaging provides a 3-D way to significantly improve the diagnosis of heart disease, according to researchers.

"The exciting results of our study show that physicians can use our technologically advanced fusion of anatomic and physiological three-dimensional color displays to significantly improve the accuracy of diagnosing heart disease," said Cesar A. Santana, assistant professor of radiology at the Emory School of Medicine in Atlanta, Ga. "In addition, these computer fusion and rendering techniques could be used in the future with molecular imaging agents to detect and guide the treatment associated with coronary artery disease," he added.