Posts

Physicists have now experimentally observed two-path quantum interference using many different particles, including electrons, neutrons, atoms and simple molecules. It’s worth checking out this very nice movie of interference fringes for electrons showing up one at a time. To date the largest objects observed to engage in this quantum jiggery pokery are molecules with 60 carbon atoms arranged like the pattern on a traditional soccer ball and 48 fluorine atoms coated on the surface of that sphere....

The number of dead in Darfur should be counted in the hundreds of thousands, not the tens of thousands that are often reported, according to a new appraisal of mortality in Sudan’s camps of displaced people. Although the actual number could be well above this lower limit, the study establishes a more realistic floor, its authors say. In February 2003 a Sudanese militia began targeting tribes in Darfur, a region in western Sudan....

Modern birds–the rulers of the sky–appear to have gotten their start in the water, scientists say. The fresh insights derive from the fossilized remains of a bird that lived some 110 million years ago and was preserved in the soft muddy bottom of an ancient lake in what is now the Gansu province of northwestern China. The amphibious, ducklike creature–named Gansus yumenensis–is the oldest known member of the so-called ornithuran group that includes modern birds....

THE WOODLANDS, Tex.—Today’s Mars is a frigid desert, a place where water—the key to life as we know it—has gone into hiding. Whatever water may have once existed on Mars in rivers, lakes or even oceans is now frozen into ice caps, locked up in hydrated minerals or buried in debris-coated glaciers. But last year compelling evidence emerged that when conditions are right, salty brines may persist to this day in liquid form at midlatitude regions on Mars....

It is never a good time to come down with tuberculosis, but in recent years the outlook has become worse. Resistant strains of tuberculosis are on the rise, limiting treatment options despite decades of antibiotic research. In 2010, at least 650,000 cases of the disease were resistant to the two most effective frontline antibiotics, and in 2012, totally resistant and effectively untreatable strains of Mycobacterium tuberculosis—the bacterium behind the disease—were detected in India....

CLIMATEWIRE | Nearly everything needs to go right for America to reach the climate targets set by President Joe Biden. So far, very little has. The Supreme Court has limited EPA’s authority to craft greenhouse gas regulations for power plants. A major legislative push ended in failure after running into opposition from Sen. Joe Manchin, a conservative Democrat from West Virginia. And the political landscape has been dramatically altered by a runup in energy prices, with gasoline prices briefly averaging $5 per gallon last month....

In January of 2010, a teenage girl named Phoebe Prince walked home from school, let herself into the family apartment and hung herself in a stairwell. Prince, who’d recently moved from Ireland, been bullied for months at school, and the bullying continued even after her death, with vicious commentary on her Facebook page. The case drew national attention and a fresh round of hand-wringing about the casual cruelty of teenagers, and the continuing failure of adults to stop it....

Mississippi may prove the first state in the U.S. to help coal fight global warming. A new facility rising from Kemper County’s loamy soil will take the dirtiest coal from a local mine, turn it to gas, strip out the climate change-causing carbon dioxide, and then burn the gaseous fuel—resulting in pollution rates comparable with a power plant that burns natural gas. If coal use can truly be made (atmospherically) clean, it could act as a powerful counter to global warming....

One ton of ivory is set to be crushed in New York City’s Times Square this Friday (June 19) to help raise awareness about the dire straits facing Africa’s elephants due to recent poaching. This will be the second such high profile event in the U.S., following the destruction in November 2013 of six tons of confiscated ivory figurines, jewelry and raw tusks at the National Wildlife Property Repository near Denver....

US researchers are banking on the hope that electrical devices implanted in the brain might one day restore memory to people who have lost it. On 9 July, the Defense Advanced Research Projects Agency (DARPA) awarded a total of $37.5 million to two research teams to study how memories are formed and retrieved and to develop devices to stimulate these processes in the brain. Here Nature offers a preview of the research to come from these awards....

Copenhagen—Even under this city’s low, leaden skies, at least one thing remained clear as leaders from 193 countries gathered to negotiate climate agreements: one ton of carbon dioxide emitted in the U.S. has the same effect as one ton emitted in India or anywhere else. That simple truism is part of a huge body of data pointing to humanity’s effect on climate, and for most negotiators, the weight of that evidence seems to have crushed any doubt they may have felt in the wake of the 1,000-plus e-mails and computer code stolen from the University of East Anglia’s Climatic Research Unit (CRU)....

What makes the unique sound of a Stradivarius violin? The wood, of course. Using x-ray images taken from multiple different angles, radiologist Berend Stoel of Leiden University Medical Center in the Netherlands proved that the spruce and maple wood used in five violins made either by Antonio Stradivari or Giuseppe Guarneri del Gesù—the rival master luthiers of Cremona—had fewer variations in their density than that in seven contemporary violins. The density of the wood determines how a violin resonates with sound, which may explain why Stradivarius and Guarnerius violins are coveted by musicians worldwide and fetch prices of several million dollars....

In 1957, when Sputnik took the world by storm, the Ford Foundation was several years into a project for talented students based on early college entrance. An evaluation of that program from the Fund for the Advancement of Education read: “There are those who argue that it is psychologically unsound and politically undemocratic for one child to proceed faster or to have a richer academic diet than another…. But what is too often ignored is the greatest risk of all—the risk of adhering stubbornly to a clearly imperfect set of practices which are frustrating the development of young talent at a time in history when this nation urgently needs to develop its human resources to the full....

Enormous herds of animals roamed the Arctic tundra thousands of years ago. Just a fraction remain today, but some scientists say they should be brought back to help fight climate change. Wild horses, reindeer, bison, musk oxen and other large herbivores trample the ground as they plod along, packing down the earth and any snow that’s on top of it. Thick and fluffy snow tends to act as an insulator, warming the soil beneath it....

In the mid-20th century the encyclopedic works of French mathematician Nicolas Bourbaki traced every mathematical concept back to the subject’s foundations in the theory of sets—the stuff of Venn diagrams—and changed the face of his field. Like many of his notions, Bourbaki existed only in the abstract: he was the pseudonym for a tight-knit group of young Parisian researchers. The Internet-age version could be D.H.J. Polymath, another collective pseudonym who could define a new style of mathematics....

In 2005 the U.S. Department of Agriculture officially released its newest Food Guide Pyramid, which was intended to help the American public make dietary choices that would maintain good health and reduce the risk of chronic disease. The new pyramid attempts to provide individualized advice based on a person’s age, gender and level of physical activity. It focuses on the consumption of grains, meat and beans, milk, vegetables, fruit, and oils....

Key concepts Water Density Physics Hydrodynamics Fluid dynamics Introduction Have you ever wondered how a ship made of steel can float? If you drop a steel bolt into a bucket of water, the bolt quickly sinks to the bottom. Then how can a steel ship float? And better yet, how can a steel ship carry a heavy load without sinking? It has to do with the density of the ship (including its cargo) relative to the density of water....

Children born to women who had diabetes or high blood pressure while pregnant are at an increased risk of autism, two new studies suggest. Autism has previously been linked to type 2 diabetes and to gestational diabetes—a temporary condition in which a woman develops diabetes during the course of her pregnancy. One of the new studies confirms these risks and extends the link to type 1, or juvenile, diabetes, the most severe form of the condition....

By Carey Gillam(Reuters) - The storm was just so sudden, South Dakota cattle rancher Kathy Jobgen remembers.A freezing rain, followed by an avalanche of four feet of snow and winds of 70 miles an hour, hit thousands of cattle still grazing on “summer pastures” at a time when the animals had not yet grown their protective winter coats and were ill prepared for the harsh conditions.Swirling snow lodged in some of the animals’ lungs, suffocating them....

About one in 4,500 babies show ambiguous genitalia at birth, such as a clitoris that looks like a penis, or vice versa. For the Insights story, “Going Beyond X and Y,” appearing in the June 2007 issue of Scientific American, Sally Lehrman talked with noted geneticist Eric Vilain of the University of California, Los Angeles, about the biology of sex determination, gender identity and the psychology and politics behind both. Here is an expanded interview....