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."
Science & Technology
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.
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.
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.
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.
Cosmologists from around the world will meet at Imperial College London next week to challenge the theories behind the 'standard model' used to understand the universe. Speakers at the four-day conference, jointly organised by Imperial and the University of Alabama in Huntsville, and sponsored by the U.S. National Science Foundation, will cover a wide range of unanswered questions on how the universe was formed and what has been happening to it after formation.
The 'Standard Cosmological Model' is the prevailing scientific theory used to explain how the universe began with the Big Bang, how it has evolved since, and how the known atoms and molecules of everyday life, along with the postulated unknowns of the universe - dark matter and dark energy - interact with each other. Speakers at Imperial's Outstanding Questions for the Standard Cosmological Model conference will present an overview of evidence for and against this model, and will look at how to probe questions that it leaves unaddressed.
The 'Standard Cosmological Model' is the prevailing scientific theory used to explain how the universe began with the Big Bang, how it has evolved since, and how the known atoms and molecules of everyday life, along with the postulated unknowns of the universe - dark matter and dark energy - interact with each other. Speakers at Imperial's Outstanding Questions for the Standard Cosmological Model conference will present an overview of evidence for and against this model, and will look at how to probe questions that it leaves unaddressed.
For all of his death-defying stunts, Harry Houdini could not escape the Grim Reaper: the unparalleled performer, age 52, died on Halloween 1926, taking with him many of his trade secrets. The rumors that he was murdered, however, soon took on a life of their own.
Eighty-one years later, Houdini's great-nephew wants to exhume the escape artist's body to determine if he was poisoned by enemies for debunking their bogus claims of contact with the dead. A team of top-level forensic investigators would conduct new tests once Houdini's body was disinterred, the legendary star's relative told The Associated Press.
"It needs to be looked at," said George Hardeen, whose grandfather was Houdini's brother, Theodore. "His death shocked the entire nation, if not the world. Now, maybe it's time to take a second look."
Eighty-one years later, Houdini's great-nephew wants to exhume the escape artist's body to determine if he was poisoned by enemies for debunking their bogus claims of contact with the dead. A team of top-level forensic investigators would conduct new tests once Houdini's body was disinterred, the legendary star's relative told The Associated Press.
"It needs to be looked at," said George Hardeen, whose grandfather was Houdini's brother, Theodore. "His death shocked the entire nation, if not the world. Now, maybe it's time to take a second look."
Using a novel quantum computing algorithm, scientists have simplified the process for finding extreme values in a database compared with classical and earlier quantum computing methods. With its reduced time and minimal error probability, this quantum process could significantly increase the speed of computing in global and mobile networks.
Sándor Imre, an engineer at the Budapest University of Technology, calls this new computing process "quantum existence testing," which is a special case of quantum counting. The quantum existence testing algorithm searches unsorted databases to find extreme values, attesting to the intriguing powers of the quantum mechanical effects of parallel processing.
Sándor Imre, an engineer at the Budapest University of Technology, calls this new computing process "quantum existence testing," which is a special case of quantum counting. The quantum existence testing algorithm searches unsorted databases to find extreme values, attesting to the intriguing powers of the quantum mechanical effects of parallel processing.
The restless bubbling and frothing of the Sun's chaotic surface is astonishing astronomers who have been treated to detailed new images from a Japanese space telescope called Hinode.
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| ©JAXA/NASA |
| Charged particles follow magnetic field lines that rise vertically from a sunspot - an area of strong magnetic field. On the edges of the sunspot, the magnetic field lines bend over to connect to regions of the opposite polarity. |
When James Cook thought he had discovered Australia and claimed it for the crown in the 18th century, he was late to the party. Another English explorer had been decades ahead in sighting the great southern land, while Dutch explorers had been charting the continent even earlier.
But evidence has emerged to suggest that neither the English nor Dutch were the first Europeans to reach the continent during the great era of epic sea adventure and global circumnavigation.
But evidence has emerged to suggest that neither the English nor Dutch were the first Europeans to reach the continent during the great era of epic sea adventure and global circumnavigation.
