Tabla de contenidos para Nov-Dec-10 en Science Illustrated

The key to a successful wave-power device, say engineers at the renewable-energy company Aquamarine Power, is a sturdy and simple design. That's the concept behind the Oyster, their device that's about a year into its trial run at the European Marine Energy Center (EMEC) off the coast of the Orkney Islands in Scotland. The Oyster looks like a waffle iron. It consists of a base anchored to the seafloor and a moving upper section that swings back and forth with each wave. Connected to the upper section are two hydraulic pistons, which, as the upper section swings, pump water to land, where it runs through a conventional hydroelectric turbine to create electricity. The engineers believe that because the Oyster has fewer moving parts than more-complex wave-power machines, it can better…

British-born journalist Arthur Wynne is credited as the inventor of the modern crossword puzzle, which debuted in the December 21, 1913, edition of the New York World newspaper. Wynne supposedly based the puzzle on a popular children's word game played in England during the 19th century. In 1901, Austrian biologist Karl Landsteiner observed that when he mixed blood from two people, the red blood cells in the mixture often clumped. He then categorized blood into types—A, B, AB and O—based on the antigens each contains that cause the reaction. Landsteiner won the Nobel Prize for Physiology or Medicine for his research in 1930. Soviet cosmonaut Valentina Vladimirovna Tereshkova became the first woman in space on June 16, 1963, when she piloted the Vostok 6 spacecraft for 71 hours as it…

Q Where does matter that gets sucked into a black hole end up? A One theory is that white holes, which have never actually been observed, expel matter sucked into black holes back into the universe. The concept is an entirely mathematical solution to the equations in Albert Einstein's general theory of relativity, which explains how gravity governs time and space. After using Einstein's equations to support the existence of black holes—where gravity pulls matter and light seemingly into oblivion—physicists started questioning where that matter goes. In 1935, Einstein and Nathan Rosen, an Israeli theoretical physicist, posited that a bridge, or wormhole, might connect a black hole to another hole that would discharge the matter. One problem: White holes can exist only in a universe where time can move backward,…

Since the 1950s, scientists have drawn three conclusions about the relation between allergies and cancer: Compared with people who don't have allergies, allergy sufferers have (1) a higher risk of cancer, (2) a lower risk of cancer and (3) the same risk of cancer. A recent review of the studies, published by scientists at Cornell University, pinpoints a nuance that could explain the apparent contradiction. Study authors Paul Sherman, Janet Sherman and Erica Holland analyzed the results of more than 600 studies published since 1955 on the correlation between allergies and cancer. Like some of their predecessors, the authors found that, with the exception of asthmatics and lung cancer, allergy sufferers do not tend to have a higher risk of cancer, as had often been assumed. In fact, they found…

Laboratory meat can be produced in many ways. If, for example, we start with muscle tissue from a cow, there are three possible methods. The most realistic for now is to make unstructured meat, similar to hamburger. Structured meat consists of muscle tissue that has had nutrients supplied through small blood vessels. Creating an artificial circulatory system with blood vessels is still a major challenge. Many square feet of membrane float in a tank of nutrients. Myoblasts attach to the membrane, divide, and eventually form a layer of muscle cells. Muscle-cell layers are harvested by scraping them off the membrane and folding the layers to create a solid mass, which can be ground. Myoblasts attach to thousands of tiny beads made either of animal protein extracted from connective tissue or…

1 Which piece from below belongs in the empty field at right? 2 An apple weighs three times as much as an acorn, and 16 twigs weigh two pounds. If four acorns, three apples and seven twigs weigh as much as six acorns, five apples and three twigs, how much does an apple weigh? 3 A six-by-eight-inch cake has a two-inch square piece cut out of it, as shown. Find a straight line that will cut the remaining cake into two equal pieces. 4 Four brothers—Andy, Bob, Carl and Dan—go to a dog show. Each has two dogs named after two of his brothers: Three of the dogs are greyhounds, three are beagles, and two are poodles. No brother owns two dogs of the same breed, and no dogs of…

Q If there's no air in space, how does the sun burn? A Despite how it looks, the sun technically does not “burn”—at least not in the way a campfire or candle does. Fire is a chemical process in which oxygen reacts with another substance, such as the carbon in wood. The sun, on the other hand, smolders as a result of atoms smashing into each other, a process known as nuclear fusion. Hydrogen atoms, the sun's dominant element, zip around the star's plasma core. When these atoms collide with enough force, they form a larger atom. When four hydrogen nuclei fuse together, they create a single helium nucleus and a neutrino to spare. Every time this nuclear reaction occurs, a tiny bit of matter is lost in the process.…

Eastern North American monarchs travel thousands of miles to the same stand of oyamel fir trees in central Mexico every year. Their guide is what's known as a time-compensated sun compass, in which they use the sun to map the journey. Photoreceptors in monarchs' antennae chart the sun's location, and the butterflies adjust their flight path accordingly. When groundwater penetrates material such as limestone, carbonate rock or salt beds, it dissolves the minerals as it moves. This creates empty pockets in the rock that can't support the weight of the land above it and cave in. Each object requires its own method. Calculating the distance between stars, for example, is different from calculating distance between galaxies. For objects in our own solar system, astronomers use the time it takes for…

Q What defines a pandemic? A The World Health Organization uses the term for any infectious disease that spreads among a significant portion of a population over a large geographic area. Based on this, WHO declared the influenza-A H1N1 virus, a.k.a. swine flu, to be a pandemic in June 2009. Although an epidemic can afflict many people in one country, a pandemic can sicken people over the entire world. With increases in global transportation and urbanization, today's epidemics can turn into pandemics faster than ever. WHO's definition does not require that a disease be especially dangerous for it to be deemed a pandemic, and there are also no time limits. Some outbreaks, like influenza pandemics, tend to last only a few years, whereas others, such as HIV/AIDS, can stretch on…

Getting to Socotra can be tricky. There are few flights to the archipelago, and the U.S. Department of State warns against travel to Yemen due to terrorist activities. But if you make the trek, you'll discover the source of dragon's blood, a red resin long regarded for its medicinal properties, and experience the islands' rich natural heritage. Although the dragon's blood tree can be found throughout the main island, Rokeb di Firmihin and the central and western parts of the Haggeher mountains feature the greatest density of individual specimens. From early October to late April is recommended, particularly after January. Avoid visiting during Ramadan, a month-long Muslim holiday, when shops and services will be closed, and the monsoon season from May to September. Felix Airways flies to Socotra four times…

When the stress between two continental plates is released deep inside the Earth, typically when the rocks along a fault line fracture and slip, powerful upheavals happen. We call these geological events earthquakes. Scientists measure the strength of these vibrations using seismometers, which combine classic mechanical seismographs with modern electronics. In one common seismometer design, a weight is suspended by a spring from a frame and exposed to electromagnets, which create an electric field. If an earthquake shakes the ground, the frame moves with it, but the electric field holds the weight motionless. The larger the tremor, the more force exerted on the field. By measuring the change in the field, scientists can determine the strength of the earthquake. A classic mechanical seismograph suspends a hanging weight from a spring…

1 If 1 = 44/44 2 = 4/4 + 4/4 3 = (4 + 4 + 4)/4 4 = 4 + 4 × (4 — 4) 5 = ? Your equation should use exactly four 4s. 2 A coin starts in the top left corner of the grid and in six moves gets to the bottom right corner. Each of the moves must be into an adjacent square. In how many different ways can this be done? 3 Which card does not belong? 4 Which number does not belong? 5 Alice and Bob have equal numbers of pennies. Alice gives half of her pennies (ignoring remainders) to Charles, and Bob gives one third of his pennies (ignoring remainders) to Charles. If Charles gets a total of 51 pennies, how many…

Q How many species of dinosaurs were there? A Pinning down exactly how many types of dinosaurs existed would require discovering at least one fossilized skeleton for every species—an unlikely scenario, says paleontologist Peter Dodson of the University of Pennsylvania. Factor in mistakes made while classifying species (scientists recently concluded, for example, that a dino they had called torosaurus is actually the adult form of triceratops), and an exact number becomes even more elusive. But this hasn't stopped researchers from trying to quantify dinosaur diversity from those species they have found. Working on the assumption that researchers will eventually unearth all the dinosaur skeletons buried in rock that is accessible to them, Dodson and Steve Wang, a paleo-statistician at Swarthmore College, used previous rates of discovery and distribution of these…

Q What is a Supervolcano? A Supervolcanoes, though exceptionally rare, are the world's most powerful volcanoes. By definition they spew out at least 240 cubic miles of ash and other magma fragments per eruption—nearly the volume of Lake Michigan—and they rate an 8 on the Volcanic Explosivity Index, the scale's highest score. In comparison, Eyjafjallajökull, the Icelandic volcano that disrupted trans-Atlantic and European air travel for six weeks when it erupted earlier this year, released just 0.03 cubic mile of material. Supervolcano eruptions occur on average once every 100,000 years, says Jacob Lowenstern, a senior geologist at the Yellowstone Volcano Observatory and the U.S. Geological Survey. These eruptions occur where magma pools just below the Earth's surface, such as at continental hotspots or along convergent plate boundaries, making the western…

The Valley of the Kings, located about 300 miles south of Cairo, has 63 explorable tombs, spanning 500 years. Visitors can also now come face to face with King Tut's mummy, which was moved from his coffin in 2007 into a climate-controlled case. The valley sits across the Nile from the city of Luxor, built around the 4,000-year-old site of Thebes. From Cairo, most visitors fly to Luxor. The one-hour flight leaves several times a day and costs approximately $200 round-trip. Adventurous travelers looking to save money can take one of several trains that depart Cairo for Luxor every day. The downside: The trip can take up to 10 hours. Traveling from Luxor (where the hotels are located) to the Valley of the Kings involves crossing the Nile. Most visitors…

Raising cattle requires significant resources and energy. Just one beef cow in the U.S. consumes more than 5,000 gallons of water and about 15,000 pounds of feed before it is slaughtered. Some research suggests that it takes 284 gallons of oil to raise a cow to slaughter, including the oil necessary to grow all that food, although the beef industry figures it's closer to 14 gallons. Either way, that's a lot of oil—today, there are almost 32 million beef cattle in the U.S. alone. Because of their size and caloric needs, cows are the worst offenders when it comes to consumption, but they are not unique in their ability to affect the planet. Thirty percent of land worldwide is dedicated to grazing livestock or raising their food, and 8 percent…

Although the human body can endure extreme spikes in temperature, shifts of just a few degrees often mean danger. Over 108°F Life-threatening hyperthermia. Significant risk of brain damage or death. Over 106.7° Severe hyperthermia. Delirium and death may occur. Over 102.2° High fever. Call a doctor. Over 101.5° Moderate fever. A person loses more than two quarts of extra fluid per day. 100.4° Slight fever. Bacterial and viral infections often cause fever. 97°–99° Normal temperature. The body's temperature changes throughout the day. It's lower in the morning and higher in the late afternoon. Below 95° Mild hypothermia. The skin is cold and pale; shivering occurs. Below 90° Moderate hypothermia. Shivering ceases. Weak pulse and respiration, possible loss of consciousness. Life-threatening condition. Below 82° Severe hypothermia. Brain function, heart, blood pressure…