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What is touch DNA? Husband-and-wife forensic experts Max and Lucy Houck get to the bottom of this mystery: The touch DNA method is so named because it analyzes skin cells left behind when assailants handle weapons, victims or something else at a crime scene. The technique of analyzing these minute samples for genetic information is relatively new, having appeared only about five years ago. Touch DNA forensics rose to prominence this past summer, when various news outlets reported that police had used the technique to clear the family of JonBent Ramsey formally of any wrongdoing in her gruesome 1996 death....

The rock that blasted a 110-mile-wide crater in Mexico’s Yucatán Peninsula and probably killed off the dinosaurs 65 million years ago may owe its origin to the breakup of an asteroid nearly as big as the crater itself. Using computer simulations, researchers reconstructed the trajectories of several thousand asteroids between Mars and Jupiter that are clustered near a 25-mile-wide rock called 298 Baptistina. They report that this so-called Baptistina family must have come from the collision of a roughly 40-mile-wide asteroid with one measuring about 110 miles wide—the parent of 298 Baptistina—some 160 million years ago....

Bouncing his knees like a drummer pounding on a bass pedal, adjusting his tie and shifting his weight in front of the multinational crowd, James Stotts was the most visibly anxious speaker. A lifelong Alaskan born and raised in Barrow—an outpost on the state’s northern coast—he also may have been the most qualified, considering how much he has to lose. “The Arctic policy that’s being set today actually is setting the stage for the next 100 years,” said Stotts, the president of the Inuit Circumpolar Council’s Alaskan branch, yesterday at the Swedish embassy during a conference on the Arctic region....

At the center of the Milky Way lurks a shadowy giant, a supermassive black hole that draws in stars and gas on which it feasts. As with all black holes, this one is an overeager eater, surrounded by piled-up material it cannot immediately consume—an accretion disk, a glowing maelstrom of gas heated by friction as it swirls around the giant’s maw. Now, new observations are hinting at the presence of never-before-seen cooler regions of the disk surrounding the Milky Way’s central black hole, opening a new window on our galaxy’s dark heart....

Medical bills drive many personal bankruptcies in the U.S., according to a survey by a Harvard University team analyzing 1,771 cases in 2001. Its report appeared online February 2 in the journal Health Affairs. Number of Americans who filed for bankruptcy in 2001: 1,458,000 Percent of bankruptcies involving any medical cause: 54.5 Percent caused specifically by*: Illness or injury: 28.3 Medical bills over $1,000: 27 Loss of work income for medical reasons: 21....

Alzheimer’s disease is now the sixth leading cause of death in the U.S., but researchers still do not know what causes the degenerative neurological disorder. In recent years they have pinpointed several genes that seem largely responsible for those cases in which the disorder develops early on, prior to age 60. They have also identified about 20 genes that can increase or decrease risk for the more common late-onset variety that starts appearing in people older than 60....

Pluto Might Be the Largest Dwarf Planet, After All For years Pluto has appeared to rank behind its fellow dwarf planet Eris in terms of diameter. New data, however, have cut Eris down to size Double Impact: Did 2 Giant Collisions Turn Uranus on Its Side? A pair of giant impacts early in solar system history could reconcile the dramatic tilt of Uranus with the equatorial orbit of its satellites Hot and Cold: Dwarf Planet Makemake Could Have Extreme Temperatures Side by Side Makemake may well have the most exotic name of the dwarf planets, and it now looks to be just as unusual on its surface Conjoined Comet: Hartley 2 May Have Formed from 2 Disparate Bodies The two ends of Comet Hartley 2 seem to have different compositions, hinting that the comet formed from the gentle merger of two parent objects Planetary Pretender: Asteroid Vesta Has Planet-Like Features NASA’s Dawn spacecraft is getting up close and personal with the giant asteroid, revealing rift valleys, mountainous uplifts and a belt of grooves near its equator Mercury Takes Shape in Color and Monochrome Maps The Messenger orbiter has just passed its first Mercury solar day–about 176 Earth days–on the job, an important milestone in its imaging campaign...

When the body contracts a new virus or bacteria, specific white blood cells—T lymphocytes—are recruited to fight back. Each T cell is only programmed, however, to recognize a specific viral or bacterial strain, so out of every 100,000 T cells, only one might match a novel pathogen. Therefore, once the matches are found, those few cells need to multiply in a hurry to stave off illness. Up to now researchers have been unsure to what extent the strength of the body’s immune response was due to the number of these T cells initially recruited from lymph nodes (clonal selection) and to what extent is was cause by the amount that those T cells multiplied (clonal expansion)....

From Nature magazine Researchers say that technology to shuffle genetic material between unfertilized eggs is ready to make healthy babies. The technique could allow parents to minimize the risk of a range of diseases related to defects in the energy-producing cell organelles known as mitochondria. Mitochondrial defects affect an estimated 1 in 4,000 children, and can cause rare and often fatal diseases such as carnitine deficiency, which prevents the body from using fats for energy....

Some 56 million years ago, during the transition between the Paleocene and Eocene epochs, Earth caught a fever. In a span of scarcely 20,000 years—not even a rounding error in most measures of geologic time—massive amounts of carbon dioxide flowed into the atmosphere, and average temperatures rose by five to eight degrees Celsius. The planet was transformed. Crocodiles basked on Arctic beaches lined with palm trees, and steamy swamps and jungles stretched across much of the midlatitudes....

His finalist year: 1976 His finalist project: Studying how organisms can regenerate parts of themselves What led to the project: As a little kid, George Yancopoulos was fascinated by such questions as how lizards can regrow their tails and how the body works. A New York City native whose parents had immigrated from Greece, “the whole reason I went to the Bronx High School of Science is that it had ‘science’ in the name,” he says....

In fact, Sandy has spurred an unprecedented amount of research, attempting to tackle the questions about what role climate change might have played in producing or worsening the storm, how global warming might influence similar storms in the future, and why the storm caused so much damage — $19 billion in the New York City area alone. “It’ll be one of the most studied storms,” said Gary Lackmann, an atmospheric scientist at North Carolina State University who has looked into the role warming might have played in guiding Sandy’s track and intensity....

In our April issue cybersecurity expert Keren Elazari argues that protecting cyberspace is a job far too large and complex for governments or corporations to handle on their own. Securing the digital realm can only be accomplished with the participation of individuals (people like you and me) as well as hackers. Yes, hackers. On balance, hackers are a force for good, Elazari argues. Big institutions should stop fighting hackers and start embracing them....

Levitating in midair, a fleck of diamond just 100 nanometers across glows brightly in a green laser beam. “This nanodiamond is just suspended in free space, and the way we hold it in place isn’t with tweezers or our fingers,” says optical physicist Nick Vamivakas of the University of Rochester. Instead Vamivakas and his colleagues use a second laser, with an invisible infrared beam, to produce an electric field that traps the diamond in place....

Lawyers quip that justice is ­what the judge ate for breakfast. New research suggests that justice might actually depend on when the judge ate breakfast. Researchers at Ben Gurion University in Israel and Columbia University examined more than 1,000 decisions by eight Israeli judges who ruled on convicts’ parole requests. Judges granted 65 percent of requests they heard at the beginning of the day’s session and almost none at the end....

By Ewen Callaway of Nature magazineA controversial new study is questioning the oft-repeated connection between the consumption of too much salt and the development of cardiovascular disease. The meta-analysis, published online today in the American Journal of Hypertension1, examined the results of seven clinical studies and found no solid proof that reducing salt consumption prevents heart conditions.The World Health Organization recommends that no more than 5 grams of salt per day should be consumed, whereas people in many Western countries typically eat twice as much....

Stem-cell trials Landmark results from an early-stage clinical trial using human embryonic stem cells (hESCs) should appear this year. Biotechnology firm Advanced Cell Technology of Santa Monica, California, is injecting hESC-derived retinal cells into the eyes of around three dozen people with two forms of non-treatable degenerative blindness. It is the only company currently testing hESC therapies with U.S. Food and Drug Administration (FDA) approval, and it hopes that the agency will give it the green light to test stem cells induced from adult cells in patients this year....

Interference from electronics and AM radio signals can disrupt the internal magnetic compasses of migratory birds, researchers report today in Nature. The work raises the possibility that cities have significant effects on bird migration patterns. Decades of experiments have shown that migratory birds can orient themselves on migration paths using internal compasses guided by Earth’s magnetic field. But until now, there has been little evidence that electromagnetic radiation created by humans affects the process....

SIGMUND FREUD popularized the idea of the unconscious, a sector of the mind that harbors thoughts and memories actively removed from conscious deliberation. Because this aspect of mind is, by definition, not accessible to introspection, it has proved difficult to investigate. Today the domain of the unconscious—described more generally in the realm of cognitive neuroscience as any processing that does not give rise to conscious awareness—is routinely studied in hundreds of laboratories using objective psychophysical techniques amenable to statistical analysis....

At 6:30 a.m. on 8 December 2020, Keenan became the first person to receive a COVID-19 vaccine as part of a mass vaccination effort. Her shot was the culmination of a frenzied effort to develop vaccines safely and in record time. Now, more than 1.7 billion doses later (see ‘Global doses’), researchers are sifting through the data to address lingering questions about how well the vaccines work—and how they might shape the course of the coronavirus pandemic that has already taken more than 3....