Astronomers just got their most detailed look yet at supersonic "bullets" of gas piercing through dense clouds of hydrogen gas in the Orion Nebula.
Each bullet [image] is about ten times the size of Pluto's orbit around the Sun and travels through the clouds at up to 250 miles (400 kilometers) per second - or about a thousand times faster than the speed of sound.
The bulk of both the bullets and the surrounding gas cloud [image] consists of molecular hydrogen. The tip of each bullet is packed with iron atoms that are heated by friction and glow bright blue in the new image, taken by the Gemini Observatory in Hawaii.
As the bullets plow through the clouds, they leave behind tubular orange wakes, each about a fifth of a light-year long. A light-year is the distance light travels in a year, about 6 trillion miles (10 trillion kilometers).
SAN FRANCISCO - It was nearly a decade ago that Jose Cibelli plugged his own DNA into a cow's egg in a novel cloning attempt that was condemned as unethical by President Clinton and landed the Michigan State University researcher in a mess of controversy.
CLAUDIA JOSEPH
Daily MailSun, 25 Mar 2007 15:20 UTC
Scientists have created the world's first human-sheep chimera - which has the body of a sheep and half-human organs.
For the first time, physicists have devised a way to make visible light travel in the opposite direction that it normally bends when passing from one material to another, like from air through water or glass. The phenomenon is known as negative refraction and could in principle be used to construct optical microscopes for imaging things as small as molecules, and even to create cloaking devices for rendering objects invisible.
VICTORIA ISLAND - A meteorite the size of four Wal-Mart Supercenters likely plunged into what we now know as the Delta, millions of years ago, according to a geologist and his teenage son.
The duo recently found what they believe to be a 3.4-mile-wide crater buried far beneath the asparagus fields of Victoria Island, about 15 miles west of Stockton.
The discovery was entirely by accident.
NYUCD study finds humans and their oral bacteria evolved from a common African ancestor
A New York University College of Dentistry (NYUCD) research team has found the first oral bacterial evidence supporting the dispersal of modern Homo sapiens out of Africa to Asia.
The team, led by Page Caufield, a professor of cariology and comprehensive care at NYUCD, discovered that Streptoccocus mutans, a bacterium associated with dental caries, has evolved along with its human hosts in a clear line that can be traced back to a single common ancestor who lived in Africa between 100,000 and 200,000 years ago.
S. mutans is transmitted from mothers to infants, and first appears in an infant's mouth at about two years of age. Caufield's findings are reported in an article in the February issue of the Journal of Bacteriology.
In his analysis of the bacterium, Caufield used DNA fingerprints and other biomarkers that scientists have also employed to trace human evolution back to a single common African ancestor, known as "ancestral Eve."
Still awaiting a more poetic name, 2003 EL61 largely escaped the media hubbub during last year's demotion of Pluto, but new findings could make it one of the most important of the Kuiper-belt objects for understanding the workings of the solar system. In a recent issue of Nature, the original discoverer of the body, Mike Brown, announces with his colleagues that an entire family of bodies seems to have originated from a catastrophic collision involving 2003 EL61 about the time Earth was forming.
Brown and his team base their assumptions on similar surface properties and orbital dynamics of smaller chunks still in the general vicinity. They conclude that 2003 EL61 was spherical and nearly the size of Pluto until it was rammed by a slightly smaller body about 4.5 billion years ago, leaving behind the football-shaped body we see today and a couple of moons, as well as many more fragments that flew away entirely.
Engineers in the US have discovered that the spin of electrons in organic nanowire "spin valves" is extremely robust. A team of researchers from Virginia Commonwealth University and the University of Cincinnati have found that the "spin-relaxation time" in these wires is at least 1000 times longer than that reported in any other system. The result means that these materials could be ideal for use in spintronics, an emerging field that exploits the spin of the electron to encode information in electronic circuits, computers and other devices.
Electrical noise, like the crackle heard on AM radio when lightning strikes nearby, is a nuisance that wreaks havoc on electronic devices. But within cells, a similar kind of biochemical "noise" is beneficial, helping cells transform from one state to another, according to a new study led by a UT Southwestern Medical Center researcher.
Dr. Gürol Süel, assistant professor of pharmacology, said his research and that of his colleagues published today in the journal Science represents "a new paradigm," suggesting that rather than being bad for biology, cellular noise might have an important function, such as prompting stem cells to transform into a specific tissue type.
The nose knows - whether it's on a fruit fly or a human. And while it would seem that how a fruit fly judges odors should differ from how a human smells, new research from Rockefeller University finds that at the neurobiological level, the two organisms have more in common than one might expect.
While it is very easy to ask a person about an odor - how intense it is, what it is similar to - it is slightly harder with an insect. "It is not known in much detail how these insects respond behaviorally to odors," says Andreas Keller, first author of the paper and a postdoc in the laboratory of Chemers Family Associate Professor Leslie Vosshall. Keller designed experiments to look at exactly how a single fly would behave when exposed to different odors. He and Vosshall found that both flies and humans judge odor intensity the same way, but differ in their judgment of quality.
In flies, as in humans, the olfactory system is composed of nerve cells, each of which expresses an odorant receptor. Each receptor recognizes a small set of odors and it is the combination of the nerves that respond to each odor that generates our, or the fruit fly's, reaction to the smell. Each animal has a different number of these odorant receptors - there are 1,200 in mice, 400 in humans and 61 in fruit flies. Vosshall and Keller wanted to know how it is that humans and fruit flies can coexist and develop such very different numbers of odorant receptors.
