Tabla de contenidos para Sep-Oct-10 en Science Illustrated

A Mammals, reptiles, birds and some fish have two nostrils, which together perform their various functions better than one. Fish use their nostrils strictly for smelling, snakes for breathing, and birds to breathe and even regulate their body temperature. In humans, two nostrils provide a a more complex sense of smell. Odor-producing chemicals dissolve at different rates—some are registered quickly as they whiz by our olfactory receptors, while others reveal their information more slowly. Our nostrils alternate taking in air at different rates, one slowly and the other quickly, which gives our nose a chance to register scents from both types of molecules. Dual nostrils also do a better job of sniffing out nasty odors. In 2006, researchers at the University of California at Berkeley discovered that two nostrils are…

Case Study: Danish researchers wanted a new way to determine the birth years of unidentified deceased persons using the bomb-pulse method, a radiocarbon-dating technique based on a pattern of increase in 14C concentrations during Cold War—era nuclear-bomb testing and a decline thereafter. Result: In 2008, a year-of-birth formula was devised based on the 14C content of certain eye lens proteins in people born after 1950. Case Study: In 1991, hikers in the Alps discovered the exceptionally well-preserved mummy of a man dubbed Ötzi, or the Ice Man. Archaeologists subjected a few milligrams of Ötzi's bones and tissue to carbon-14 dating, along with traces of grass and charcoal found next to his body. Result: Ötzi was about 5,300 years old, and the charcoal 1,000 years older, proving that people lived in…

Since 2003, Ray Berkelmans and Madeleine van Oppen, research scientists at the Australian Institute of Marine Science, have moved staghorn coral to see if they can survive a relocation from their warmer native waters to cooler waters elsewhere in the Great Barrier Reef. Historically, those species that survived warming climates did so by migrating to new habitats on their own. Cold-climate species moved toward the poles or up mountains, where it was cooler, and warm-climate species expanded their ranges to fill the larger warm regions. But the Intergovernmental Panel on Climate Change reports that global temperatures are increasing at accelerated rates, and industry has altered habitats, leaving some species with little time or freedom to adapt. Unintentional barriers caused by drained wetlands, plowed fields, and road and building construction have…

In 2009, anthropologist Steven Churchill of Duke University determined that a spear thrown at the chest of a Neanderthal dubbed Shanidar 3 might have caused his death. Because Neanderthals didn't have the range of motion in their shoulders to throw a spear, this implied a human perpetrator. And a Neanderthal jaw later found in a human encampment in France bore butchery marks that indicate human-Neanderthal violence. Evidence of Neanderthal cannibalism also exists. Similarly butchered Neanderthal bones and red-deer carcasses have been found together among a cluster of the species' remains in Ardèche, France. Eight Neanderthals have turned up in a cave in northwestern Spain with similar features. With their high energy needs, these losses in life could have dealt blows to Neanderthal populations if those killed or cannibalized were skilled…

In 1919, German physicist Albert Betz calculated that a wind turbine can, at best, convert 59 percent of the energy in a gust of wind into electricity, and this limit still holds. Improvements in turbine aerodynamics and technology let today's windmills capture approximately 80 percent of Betz's theoretical maximum, sending 50 percent back to the grid. Here's how they work. Instead of traditional gearboxes, which use an array of mechanical parts, new turbines have direct-drive generators that use powerful magnets to induce current as they pass each other. With fewer moving parts and more-efficient power, they could revolutionize wind energy. HOW MUCH NOISE A WINDMILL MAKES 100 dB 110dB Rock concert 85 dB Traffic noise 60 dB Conversational speech 50 dB 35–45 dB Windmill noise 0 dB 0 dB Hearing…

Since the 1950s, silicon has been used for temporary memory. Earlier this decade, silicon started to replace magnetic materials for long-term data storage as well, as spinning-platter hard drives ceded ground to SD memory cards and flash memory in portable devices. But the heyday of those technologies might be coming to an end with the arrival later this year of a strong competitor. It's a form of glass that, with a bit of heat, combines the best elements of RAM and flash memory in a package that can fit any portable device. First, an introduction to memory chips and how they work: Electronic memory stores data by collecting electrical charges—groups of electrons—in memory cells on a computer chip. One memory cell equals one bit of memory, and the presence or…

Homo neanderthalis and Homo sapiens emerged at roughly the same time, 400,000 to 500,000 years ago. But archaeological evidence suggests that their societies developed differently. Some 80,000 years ago, early humans in Africa were already creating jewelry and art. At encampments like the Blombos Cave in South Africa, scientists have discovered the earliest known arrowheads and stones engraved with red-ochre patterns. Mussel shells and stones found in early human settlements far from their areas of origin are evidence of long-distance trading networks and new levels of economic organization. These advancements, argues Stanford University paleoanthropologist Richard Klein, show that early humans had a great capacity for inventiveness and adaptability. Yet Neanderthal sites in Asia Minor (modern-day Turkey) and Europe, where the group dominated before the arrival of humans from Africa 40,000…

1 Explain why it is impossible to enter the numbers from 1 to 20 into the boxes of a 5×4 grid in such a way that the sums of the've numbers in each vertical column are all equal. 2 What number should come next? 3 Find a path from A to B that does not break through any of the hedges. 4 In five years, John will be three times as old as he was three years ago. How old is John today? 5 Divide this figure in two with a single straight cut to create two identical figures that are mirror-images of each other. 1. It is impossible because if the sum of the numbers in each column is S, then 4S = 1 + 2 + 3 +…

Today we take for granted that we can precisely determine the age of ancient fossils, man-made objects and natural disasters. But until 1949, when University of Chicago chemist Willard Libby developed radiocarbon dating, archaeologists had only written records or the estimated age of the rock strata in which a specimen was found. Or they compared unknown objects with those of known ages. Libby's method, for which he received a Nobel Prize in 1960, contrasts the ratios of carbon's isotopes—carbon atoms with different numbers of neutrons—in ancient specimens with modern atmospheric levels. All living organisms take in carbon from the atmosphere. The amount of non-radioactive isotopes (carbon-12 and carbon-13) in the organism's cells remain the same after it dies, but radioactive carbon-14 isotopes start to decay. The older the cells are,…

Most electronic devices today use RAM and flash memory to store data. But PCM could eventually replace them. RAM temporarily stores programs and other information, but before the computer is powered down, data must be saved to the hard drive or it disappears. Flash is often used to store data in handheld devices like MP3s and phones. Unlike RAM, flash memory works even without electrical power. The first PCM chips may be used much like flash memory. Later, PCM could replace RAM in computers as well.…

Climatic extremes across Europe and Asia, documented in ice-core and pollen records, occurred at roughly the same time that Neanderthals started disappearing from the fossil record. Some regions experienced severe flooding, while others transitioned from forested landscapes to treeless grasslands and back again in just a few generations. As the climate and landscapes changed, so did animal populations: Woodland creatures, such as red deer, gave way to animals like the woolly mammoth, which thrived in grasslands. Early humans, with their relatively small, slim bodies, could chase such prey on an open landscape. But the stocky Neanderthal physique—ideal for attacking animals from hiding places—was poorly equipped to give chase, argues anthropologist Clive Finlayson of the Gibraltar Museum. Neanderthals' broad, heavy bodies, though naturally built for staying warm, further doomed them. They…

1 The number keys have been switched on a calculator and no longer represent the real values. Using the solutions in black, determine the real values for each of the number keys 0 through 9. 2 The same cube is shown from three different angles. What colors are opposite the yellow and red faces? 3 How many quadrilaterals can you find in this figure? 4 Mary is thinking of a three-digit number. She makes four statements below, at most one of which is incorrect. What is Mary's number? A. My number is a square. B. My number is a cube. C. My number is a multiple of 15. D. No two of the digits of my number are equal. 1. Key 0 is really 7, 1 is really 9, 2…