Argentine ants dependent on water
A University of California-San Diego study has shown water to be mainly responsible for Argentine ant invasions. David Holway, an assistant professor of biology who conducted the study with graduate student Sean Menke, found Argentine ants in Southern California need wet soil to live and breed. So residents plagued by indoor infestations might find relief by shutting off or substantially limiting the use of outdoor irrigation. The scientists say they were able within a matter of weeks to increase the abundance and encourage the spread of Argentine ants by irrigating normally dry land. Once irrigation ended and soil moisture declined, the researchers found, the number of ants returned to pre-irrigation levels. The dark-brown ants, are about 3 millimetres in length, are thought to have entered the United States aboard ships carrying coffee from Brazil during the 1890s, then expanded throughout California and the southern parts of the United States.

Best Seat in the House
Ever since the Aeron chair became a status symbol at startups, furniture makers and industrial designers have been trying to craft superior seats for the desk-bound. Today's chairs exploit technologies that would flummox a NASA engineer: cellular suspension, back flexors, thermal comfort systems, power mechanisms, form-sensing mesh ... heck, there's even a chair marketed as having a conscience. Though we're not convinced that any of these progressive perches is actually sentient, each can make your workday a whole lot more comfortable, as long as you're willing to put up with co-worker envy and can afford it. The Steelcase Think was less tweakable than most models tested, but it had the remarkable ability to adjust itself to different people. Its wireback flexors provided excellent support and were very comfortable.

Feels sensational, says robot finger
Robots can reach people trapped under a collapsed building, fire weapons and even perform brain surgery, but they still struggle to pick a coin up off the ground. That's because although robotic hands are remarkably dextrous, they can't "feel" where one surface ends and another begins. A new robotic finger developed by Koh Hosoda and colleagues at Osaka University in Japan can distinguish between different materials, such as paper, cork, vinyl or wood, just by touching their surfaces. It does this using sensors to assess the texture and friction of each material. The finger has been designed to more closely resemble the structure of a human finger, with strain sensors distributed at different depths throughout its silicone "flesh".

Ethanol Hybrid Passes on Gas
GM today unveiled a Saab concept vehicle that runs on ethanol and battery power. When combining the power sources, the car can produce three times as much torque as a gasoline vehicle and it cuts the 0-60 speed by almost two seconds, according to GM. The BioPower Hybrid can be switched to city mode to run purely on electricity for short trips. The vehicle has two electric motors, including one in the back to drive the rear wheels. Saab is currently selling a flex-fuel version of the BioPower in Sweden.

Many human genes evolved recently
Human genes involved in metabolism, skin pigmentation, brain function and reproduction have evolved in response to recent environmental changes, according to a new study of natural selection in the human genome. Researchers at the University of Chicago, US, developed a statistical test to find genomic regions that evolution has favoured over the last 15,000 years or so when modern humans dealt with the end of the last ice age, the beginning of agriculture, and increased population densities. Many of the 700 genes the researchers identified especially those involved in smelling, fertility, and reproduction are also suspected of having undergone natural selection during the divergence of humans and chimpanzees millions of years ago. But some of the newly identified genes fall into categories not previously known to be targets of selection in the human lineage, such as those involved in metabolism of carbohydrates and fatty acids.

Solar Roof Soaks Up the Rays Incognito
Everybody knows that the sun is the energy source of the future, but not everyone has $50,000 to take their home off the grid. And many of those who do have the money happen to live in snooty upscale developments that would sooner have you burn your house down than deface its roof with an array of solar panels. Enter Solar Century, which is launching a line of solar panels that actually replace your home's existing roofing tiles. The product will officially unveil later this month at Interbuild 2006 in the UK, so pricing details aren't available yet. We're sure you'll still have to be both snooty and upscale to afford them, though.

Handheld scanners could spot drugs and bombs
Portable scanners that can instantly detect concealed drugs, weapons and explosives are a step closer with the development of a compact method for generating terahertz radiation. Researchers at the University of St Andrews in Scotland, UK, came up with a terahertz generator that could fit into a large shoebox. This could help reduce the size of terahertz scanning devices, which are currently the size of a small car. "This will take the potential of terahertz radiation out of the lab and into the street," says laser specialist Malcolm Dunn from St Andrews. "Making the components that produce the terahertz beam more compact also means we get more power from less energy, so there's no need for a huge power source or cryogenic cooling." Terahertz radiation lies between infra-red and microwaves on the electromagnetic spectrum. It passes straight through plastic, fabric, wood and stone but can be used to spot other compounds, including certain drugs, metals and explosives, as it interacts with the weak bonds that form between larger molecules. Terahertz radiation is also non-ionising and is therefore harmless to people.

Compiled by IMRAN H. KHAN

Source: NewScientistTech, Wired and Webindia123

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