Wednesday, June 25, 2003

Human Diversity — Going Deeper There is not one gene, trait, or characteristic that distinguishes all members of one race from all members of another. We can map any number of traits and none would match our idea of race. This is because modern humans haven't been around long enough to evolve into different subspecies and we've always moved, mated, and mixed our genes. Beneath the skin, we are one of the most genetically similar of all species. (06/25/03) The Huddle and the Squabble Howard Bloom writes: In previous episodes we've focussed on two kinds of conformity enforcers: ones which shape brains to work in harmony, sculpting our vision,hearing and attention so that we comprehend the world in a similar way; and others which goad individuals to tailor their behavior and appearance to the standards of the tribe. Conformity gives the complex adaptive system, the social group, its stability.But to adapt, the system needs a hefty dollop of something else: novelty. The ability to bend, stretch, and create comes not from the conformity enforcers but from their indispensable opposites: diversity generators. Diversity generators show up in many forms. They snake through the inanimate universe, where physicist Paul Davies says there's no telling "what new levels of variety or complexity may be in store." Random fluctuations, explains Davies, "are nature's way of exploring unforeseen possibilities." On the living level there's that old phenomenon called sex. It is a time-consuming, energy-swallowing waste of an organism's time. But the diversity it produces gives the ability to make gene repairs. This provides sexual organisms with an edge when they're pummeled by high-energy particles able to snap vital twists of DNA. Some bacteria hang on to chromosomal uniformity - simply splitting in half and giving each daughter a replica of her mother's genes. Others mix and match their genes with those of a chosen mate. The pay-off comes when the atmosphere fails to protect the micro-beasts against the sun's toxic ultraviolet waves. Then sexually shuffled bacteria out-survive the neatly uniform non-sexual ones. (06/25/03) If you don't mind, it doesn't matter! New Scientist -- Doctors and nurses have known for many years that some people are more sensitive to pain than others. Now brain scans of people experiencing the same painful stimulus have provided the first proof that this is so. But the scans also suggest that how much something hurts really is "all in the mind". "We saw a huge variation between responses to the same stimulus," says project leader Bob Coghill of the Wake Forest University School of Medicine in Winston-Salem, North Carolina. "The message is: trust what patients are telling you." Coghill tested the pain tolerance of 17 healthy volunteers by applying heat to the back of their calves. He varied the heat from around body temperature to 49 °C, the temperature of very hot washing-up water. Volunteers asked to rate the pain on a scale of zero to 10 showed huge variations. One resilient volunteer rated pain at the hottest temperature at just over one, whereas another could scarcely bear it at all, rating it at almost nine.  (06/25/03) A Solar Powered Airplane BBC Science -- British engineers are preparing to push the limits of aeroplane technology. Boxed and set: Zephyr sits in its packing case ready for despatch Zephyr 3, a solar-powered propeller-driven vehicle, is set to fly to 132,000 feet (40 kilometres) in the next few months. Only experimental rocket planes and the space shuttle will have gone higher. It will rise into the stratosphere to take pictures of a giant helium balloon that will attempt to break the world altitude record for a manned envelope. But Zephyr - built by QinetiQ, a commercial offshoot of the UK's Ministry of Defence - is more than just a flying camera gantry. The prototype vehicle, and others like it, may soon lead to a cheap alternative to space satellites. Squadrons of these high-flying solar planes could be stationed permanently in the sky, for use in environmental monitoring or to supply immediate mobile phone coverage in remote areas, perhaps in a disaster zone. The all-up mass is just 14 kg Its five motors consume 1 kW It will beam still photos to Earth. (06/25/03) The Fastest Desktop in Town CNN Technology -- Apple Computer introduced on Monday its new "G5" computer chip, a breakthrough design by International Business Machines which can handle twice as much data at once as traditional PC microchips. ... the G5 chip, which can manage 64 bits of data at once, compared with 32 bits for traditional computers. "The PowerPC G5 changes all the rules. This 64-bit race car is the heart of our new Power Mac G5, now the world's fastest desktop computer," Steve Jobs told the company's Worldwide Developer Conference in San Francisco. (06/25/03) What to be healthier? Exercise CNN Health -- Doctors should regularly prescribe exercise as a way to lower blood pressure and prevent heart disease and diabetes, the American Heart Association said on Monday. Exercise often works well as drugs, yet doctors fail to advise patients to get off their sofas and walk, cycle or run, the group said, citing data from 44 different studies. The American Heart Association and U.S. Centers for Disease Control and Prevention, among other groups, recommend 30 minutes or more of moderate exercise such as brisk walking on most or all days of the week. ... The recommendations, published in the association's journal Circulation, show that regular modest exercise can raise HDL, or "good," cholesterol by 4 percent and lower LDL and triglycerides, the "bad" cholesterol, by 4 to 5 percent. The CDC reported on Monday in the Archives of Internal Medicine that patients with type-II or adult onset diabetes who walk as little as two hours per week lower their risk of dying prematurely by more than one-third. (06/25/03) 5:51:33 AM

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