Discover的March 2015目录

At the University of Notre Dame Environmental Research Center’s (UNDERC) field station in Michigan’s remote Upper Peninsula, more than a dozen doctoral students went beyond the bounds of academia to combat invasive plants and animals. The group spent their days collecting data for their dissertations, helping point to strategies to keep exotic species in check. But evenings at the Michigan field station saw the team experimenting with another approach to controlling invasives — eating them. “I’ve always thought real biologists shouldn’t be afraid to eat their study organisms,” says Andrew Deines, who spent a few weeks during the past few summers at the field station wading through rivers and wetlands with his gastronomically intrepid colleagues. Invasivorism at the center began as a fun outreach project in 2011, and it simultaneously…

In retrospect, you can’t believe you missed it: three different days, the same diagnosis. They pop back into your head: the kid hanging off the chair, left arm askew; the three-piece-suit-and-briefcase guy, head jerking like a man with runaway Tourette’s; the 30-something Latino clutching his chest. The kid showed up on a busting-at the-seams Friday night. “Doc, it kills. Oh gawd, it kills,” he wailed, cradling his left arm. The 20-something had a junior camp counselor look to go with his Long Island accent. Obvious shoulder dislocation. Quick discharge. I grabbed him ahead of three other patients. “Doc, you’re the best!” he cried. “How do I fix this? The shoulder keeps slipping out and dislocating. If only that drug addict hadn’t kicked me in the ambulance.” “You were a medic?”…

More than a hundred years ago, German physician Alois Alzheimer did a grim postmortem analysis of the dementia-ravaged brain of one of his patients. He hoped to unmask the biological roots of her severe and rapid mental deterioration and bizarre mood swings. Her name was Auguste Deter, and she was admitted to the Hospital for the Mentally Ill and Epileptics in Frankfurt in 1901. When Alzheimer first interviewed the 51-year-old woman, she was enveloped in a fog of confusion, and she exhibited delusional behavior: She was intensely jealous of her husband; she sometimes would start screaming, thinking people wanted to kill her; and she became wild and uncontrollable. She died five years later. When Alzheimer examined thin slices of her brain under a microscope, he noticed that nestled right next…

Pyramids and pharaohs: iconic images of ancient Egypt, but what came before the massive tombs and elaborate burials? New analysis of old evidence is shaking up conventional thinking about how early, how quickly and even why prehistoric nomadic societies coalesced into the world’s first formal state. A key to understanding the surprising new chronology of ancient Egypt’s foundation can be found in tiny, “toffee-like” shards of material, some of which are more than 6,000 years old. In 2014, researchers rewrote the timeline for mummification — moving its start back in time by millennia — when University of York archaeological chemist Stephen Buckley analyzed several fragments of funerary textiles and reed matting dating from 4500 to 3350 B.C. The fragments spanned two key periods in prehistoric Egypt: the Late Neolithic, or…

A new oral drug can improve vision in people with a specific form of blindness, researchers announced in July. A team led by pediatric ophthalmologist Robert Koenekoop at McGill University gave the medication to 14 patients with Leber congenital amaurosis, an inherited disease that causes retinal degeneration leading to blindness. Ten of the patients, both children and adults, saw their visual field expand, and six experienced improved visual acuity, according to the team’s study, published in The Lancet. “This is very exciting; we could possibly provide treatment for these disorders that until very recently were considered untreatable,” says Janine Mendola, a McGill neuroscientist involved in the study. INBOX Expansion Explanation In November, “20 Things You Didn’t Know About . . . Galaxies” threw one reader for a loop. Two sentences…

A hospital is a place of healing, but sometimes patients acquire new medical problems during their stays, such as catheter-related bloodstream infections. To prevent these potentially deadly infections, hospitals traditionally use the blood-thinning drug heparin to block germattracting blood clots from forming inside catheters. But a Henry Ford Health System study found that cleaning catheters with an antibiotic combination of gentamicin and citrate, instead of heparin, lowered mortality rates a whopping 68 percent. If widely implemented, this simple procedure could save thousands of lives each year. DID YOU KNOW? In 1991, University of Cambridge computer scientists invented the first webcam, and its broadcast became one of the most popular sites on the early Internet. What did it show? The break room coffee pot — so the scientists could determine whether…

Reviving a woolly mammoth will be no easy feat, but below are two plausible methods. The first requires remarkable luck to find a mammoth cell with a viable nucleus. The second requires painstaking efforts — which are underway — to modify the Asian elephant’s genome to resemble the mammoth’s. Eventually, scientists might use mammoth genome sequences to synthesize chromosomes, which could be placed in a nucleus that then is placed in a cell and grown into an embryo, which could be implanted in a surrogate mother. The elephant genome is modified with mammoth genes for cold resistance, such as long hair, extra subcutaneous fat and an altered blood protein Cloning With Somatic Cell Nuclear Transfer 1 Extract egg from Asian elephant donor, then swap in nucleus from mammoth cell. 2…

“Follow the water.” That’s been a guiding principle in the modern search for extraterrestrial life, based on the overwhelming evidence that all living things on Earth — no matter how exotic or extreme — require water to survive. For the past two decades, this emphasis on water has focused attention on Mars, where NASA has intently sought evidence of ancient rivers or modern trickles. Each eroded pebble and layer of sediment there has been heralded as an important clue. Lately, though, the celestial dowsing process has been pointing in a sharply different direction, away from the majestic deserts of the Red Planet and toward a motley assortment of small, frozen bodies. The shift began in the late 1990s, when the Galileo spacecraft gathered evidence that Jupiter’s moon Europa has a…

As a graduate student in the late 1970s, David Reznick set out on a modest quest to test a key part of the theory of evolution. Reznick wanted to examine Charles Darwin’s concept of the struggle for existence — specifically, how predator-prey interactions shape the evolution of new species. Enthusiastic and ambitious, he intended to do it in the wild. “I wanted to watch evolution happen,” says Reznick, now an evolutionary biologist at the University of California, Riverside. So in 1978, he flew to Trinidad in search of guppies. Armed with a topographic map traced onto a piece of notebook paper, he headed into the Caribbean island’s rugged Northern Range. Working under a canopy of tropical trees amid squawking birds, multicolored butterflies and boas, he collected 1,600 guppies, a colorful…

Scorpions may call to mind snapping pincers and a poisonous sting, but these ancient arthropods are far from invincible. To survive in harsh environments and evade predators like lizards and owls, many scorpions spend most of their time hunkered in their underground burrows. To learn more about the scorpion’s retreat, physiological ecologist Berry Pinshow of Israel’s Ben-Gurion University of the Negev focused on Scorpio maurus palmatus, or large-clawed scorpion, which is common in Israel. He teamed up with behavioral ecologist Amanda Adams to capture some 30 scorpions and map out their homes. By pouring molten aluminum into the burrows and creating 3-D images of the resulting casts, the pair was surprised to find a consistent shape with sharp curves. The pattern suggests this scorpion species has evolved a simple yet…

In June, an isolated tribe known to semi-permanently reside in Peru emerged from the forest on the neighboring Envira River in Brazil to make contact with the outside world. Such contact happens surprisingly often, but it is usually brief. “This is unique in that they’ve chosen to stay,” says Chris Fagan, director of the nongovernmental group Upper Amazon Conservancy. Reportedly under threat from illegal loggers, a few dozen tribespeople remain near the village where they first emerged. They are under the supervision of FUNAI, Brazil’s agency for Indian affairs. During many past contact events, members of the isolated groups died after encountering modern diseases for the first time. But experts hope the group that emerged in June will fare better because members have stayed long enough to receive medical care.…

Take a look around: Every single thing you see is made up of elements in the periodic table. Ever since scientists first cobbled together these catalogs of nature’s building blocks in the 19th century, they have wondered if there was any end to the elements and their variants, called isotopes. It’s a profound question at the heart of the physical universe. Nowadays, we have 118 elements on the books, distinguished by the number of protons in their nuclei. About two dozen of these elements, however, do not occur in nature. Over the years, physicists have conjured new, short-lived and typically supersized elements (as defined by their atomic number, or proton count) by smashing atomic nuclei together in particle accelerators. Hordes of interesting isotopes also have emerged from these colliders. Each…

ILLUSTRATION BY MARCOS CHIN HENDRIK POINAR had no idea the bizarre turn his day was about to take. Perched on a leather sofa in a downtown Toronto office, his host, a wealthy businessman, uncorked a $7,000 bottle of wine and outlined the multimillion-dollar offer: leave behind his research position at McMaster University’s Ancient DNA Centre in Ontario and work full time to bring the extinct woolly mammoth back to life. The businessman went on to describe a grand vision — a “Pleistocene Park” housed on 150 acres north of Toronto, where visitors would pay to see the herbivorous beasts. Throughout the three-hour lunch, he peppered Poinar with questions about the risks and feasibility of such an endeavor, trying to feel out how much skin Poinar was willing to put in…

Nothing fills movie theaters like the end of the world, which may be why Hollywood keeps turning out apocalypses. Yet most big-screen disaster scenarios pale in comparison to the genuine cataclysm that befell Earth some 66 million years ago, when a 6-mile-wide asteroid slammed into our planet. It left behind a roughly 120-mile-wide crater in the Yucatan and wreaked global environmental havoc. Many scientists believe this was the event that wiped out the dinosaurs and about 80 percent of all animal species. Events of this magnitude are rare, but astronomers assure us something similar will happen again. Nature provided a little reminder on Feb. 15, 2013. First, a 56-foot-diameter rock exploded without notice above the Siberian city of Chelyabinsk, releasing the energy of more than 30 Hiroshima-size atomic bombs. Later…