October 16, 2012, 11:11 am
New Orleans — For the 270,000 people in the United States who live with spinal-cord injuries, the hope of walking again is never far from their minds. It has, sadly, been farther from reality, but today it seems a little bit closer. Some unusual technologies—electrodes placed in the brain, far from the injury, and a gas that most people think of as toxic rather than healing—are showing promise in early tests.
Studies of those tests, presented on Monday at the Society for Neuroscience meeting here, have been limited to animals, but they show how neuroscientists are rethinking nerve damage once deemed permanent and crippling.
“Most of these injuries are not complete. They are partial,” said Jacqueline Bresnahan, a researcher in the department of neurological surgery at the University of California at San Francisco. “Some connections remain.” It may be possible to take advantage…
October 2, 2012, 4:07 pm
The new fanged dinosaur, Pegomastax africanus.
The diets of dinosaurs have been told by their teeth. The blade-filled mouth of Tyrannosaurus rex speaks of ripping chunks of meat off prey or carrion. The blocky dentition of long-necked Apatosaurus or horned Triceratops tells of grinding up plants. In fact, for a long time paleontologists believed that each kind of dinosaur had only one kind of tooth.
But a newly found dinosaur, something its discoverer calls “a little, punk-sized critter,” speaks out of both sides of its fanged mouth. And the tale it tells is of teeth that may have little to do with eating.
Pegomastax africanus, described and named on Wednesday in a paper by the paleontologist Paul C. Sereno, was about the size of a house cat. While its cheeks were filled with plant-mulching teeth, its…
September 28, 2012, 1:06 pm
On Thursday off the coast of Hollywood, Fla., George L. Hanbury (left), president of Nova Southeastern University, went underwater as his institution celebrated the opening of a large coral-reef research center. The center is connected to this nursery, one of many along the Florida coast.
“This is pretty cool stuff. There are several sites operated by different institutions, in which we’re growing endangered corals and repopulating denuded reefs,” says Diego Lirman, an associate professor of marine biology and fisheries at the University of Miami. His institution helps run a large nursery in the Florida Keys. “We are learning how these species survive.”
(Image courtesy Nova Southeastern U.)
August 30, 2012, 2:00 pm
A replica of the Denisovan finger bone sits on a human hand.
The young woman from southern Siberia has been tantalizing scientists for about two years. They knew a few skimpy details, like that she was a she, and lived at least 50,000 years ago. Also she was not a modern human, but she or others in her group may have mated with our more direct ancestors, contributing a little DNA we still carry today.
Today we know what her DNA is—and more important, we have a better sense of what genes are uniquely ours. Many of them have to do with brain development and vision, and could be traits that set us apart from these near-modern humans in Siberia called Denisovans, their sister group the Neanderthals, and other shadowy relatives in Africa.
A newly unveiled and highly detailed genome map reveals those…
August 2, 2012, 5:51 pm
ChemCam in action, in an artist’s view.
Early on Monday, after a tricky parachute descent, a hovering spacecraft will lower the new Mars rover, Curiosity, to the planet’s surface with long cables. If the nail-biting, never-before-tried maneuver works, the remote-controlled vehicle will begin searching for signs of water—and life. Bethany Ehlmann, an assistant professor at Caltech, will play a key role. From a control room in Pasadena, Calif., she will blow holes in rocks with a laser on the rover, creating clouds of atoms that could hold evidence of water. She spoke with The Chronicle about the quest.
Q. This sounds like a point-and-shoot game, something in a video arcade.
A. I can see that. This is the first time …
July 26, 2012, 12:20 pm
We are not alone. An unknown group of archaic humans interbred with our more modern species in Africa thousands of years ago, contributing DNA that is still with us, according to a new scientific paper. These ghosts within our genome are revising the history of Homo sapiens, which once was thought to have crushed any humanlike competitors on its way to inheriting the earth. In reality, we had sex and had kids with these extinct groups.
In fact, this is the third population of archaic humans—groups slightly different from the modern mold—that we consorted with. Within the last two years, scientists have pulled ancient DNA from Neanderthal bones and learned that it matches some of ours. And a finger bone from a cave in Siberia, belonging to a 30,000-year-old group called the Denisovans, has yielded a different set of DNA that we carry as well. Now comes evidence of these unknown…
July 23, 2012, 1:50 pm
Forty years ago today, NASA launched its first Earth-observation satellite, Landsat. Data from the program, now on its eighth orbiter, have been used in climate-change studies, in ecology, and to show the effects of population growth.
Scientists have also noticed that some images are just visually amazing. (Particularly when the researchers add color to the pixels.)
Here are two of the most popular, voted on by 14,000 members of the public. The first contrasts the graceful oxbow bends of the Mississippi with the blocklike parcels of land that surround it. The second highlights one of the largest—and least-seen—river deltas in the world: the Yukon Delta in southwest Alaska, featuring a multitude of ponds, sloughs, and other water-forms.
(Credit: NASA’s Goddard Space Flight Center/USGS)
July 5, 2012, 11:56 am
On the bridge of the "Endeavor," crew members search the ocean for a wayward floating probe that is crucial to the ship's scientific mission.
The ecological effects of the 2010 Deepwater Horizon oil spill are still largely unknown. A senior writer at The Chronicle, Josh Fischman, is on the research vessel Endeavor in the Gulf of Mexico, with a team of university scientists seeking answers. He is filing reports from the ship.
About 120 miles southeast of Gulfport, Miss. — We all want to go home. The Endeavor’s scientists have been trolling the gulf since May, with only two port calls to break up the round-the-clock work. But there always seems to be more mud to pull from 1,200 meters below, or water to sample at 800 meters and 600 meters and 450 meters and one meter. And more microbes to…