![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
Entry tags:
Science Tuesday - Floresians, Plaque, Math, and MRSA's
Report Reignites Feud Over ‘Little People of Flores’
By JOHN NOBLE WILFORD, The New York Times, August 22, 2006
After the 18,000-year-old bones of diminutive people were found on the Indonesian island of Flores, the discoverers announced two years ago that these were remains of a previously unknown species of the ancestral human family. They gave it the name Homo floresiensis.
Doubts were raised almost immediately. But only now have opposing scientists from Indonesia, Australia and the United States weighed in with a comprehensive analysis based on their own first-hand examination of the bones and a single mostly complete skull.
The evidence, they reported yesterday, strongly supports their doubts. The discoverers, however, hastened to defend their initial new-species interpretation.
The critics concluded in an article in the current issue of The Proceedings of the National Academy of Sciences that the “little people of Flores,” as they are often called, were not a newfound extinct species.
They were, instead, modern Homo sapiens who resemble pygmies now living in the region and, as suggested in particular by the skull, appear to have been afflicted with the developmental disorder microcephaly, which causes the head and brain to be much smaller than average.
The international team of paleontologists, anatomists and other researchers who conducted the study was headed by Teuku Jacob of Gadjah Mada University, who is one of Indonesia’s senior paleontologists.
In the report, Dr. Jacob and his colleagues cited 140 features of the skull that they said placed it “within modern human ranges of variation.” They also noted features of two jaws and some teeth that “either show no substantial deviation from modern Homo sapiens or share features (receding chins and rotated premolars) with Rampasasa pygmies now living near Liang Bua Cave,” where the discovery was made.
“We have eliminated the idea of a new species,” Robert B. Eckhardt, a professor of developmental genetics at Penn State who was a team member, said in a telephone interview. “After a time, this will be admitted.”
That time has not yet come.
Peter Brown, a paleontologist at the University of New England in Armidale, Australia, who was a leader of the team that discovered the “little people” bones, took sharp issue with the new report.
In an e-mail message, Dr. Brown said, “The authors provide absolutely no evidence that the unique combination of features found in Homo floresiensis are found in any modern humans.”
The features he referred to include body size, body proportions, brain size, receding chin, shape of premolar teeth and their roots, and the shape and projection of the brow ridge. But the critics asserted that many of the features in the specimen with the cranium, said to be diagnostic of a new species, are present in the Rampasasa pygmies.
Dr. Brown said the critics’ claim of “the asymmetry of the skull being the result of abnormal growth is fiction.” The skeleton was buried deep in sediment, he said, and this brought on “some slight distortion.”
In response, Dr. Eckhardt said, “Our paper accounts neatly for everything we see in the asymmetry” of the face and other parts of the skeletons.
Dr. Brown said an independent study led by Debbie Argue, an anthropologist at the Australian National University in Canberra, discounted microcephaly as an explanation. He said the report, accepted for publication in The Journal of Human Evolution, “completely supports my arguments for a new species.”
Dr. Argue’s group, which included Colin Groves, also of the Australian National University and an authority on primate taxonomy, wrote that its comparisons of the Flores specimen with modern and early humans, pygmies and microcephalic humans showed it was unlikely that the skull belonged to a microcephalic human or to any known species.
The bones at the center of the controversy were excavated from a limestone cave on Flores, an island 370 miles east of Bali, by Australian and Indonesian archaeologists.
The most complete specimen was estimated to be 18,000 years old, and other remains of as many as seven other individuals ranged from 95,000 to 13,000 years old.
The Floresian adults stood just three and a half feet high and had brains of 380 cubic centimeters, about the size of the apelike human ancestors known as australopithecines, which lived more than three million years ago.
The find was announced in October 2004 in the journal Nature by a group headed by Michael J. Morwood, also of the University of New England. Dr. Brown was the lead author of a companion report that assigned the little people to a new human species.
In the time since, the dispute over the interpretation has often veered in nonscientific directions, sometimes trampling on national pride.
Indonesian paleontologists complained that the Australian scientists took most of the credit for the discovery and put their own stamp on the interpretations. They were also upset by what they said was the limited access they had to the specimens for their own analysis.
The discoverers countered that the Indonesian researchers had mishandled the bones. They also disparaged the quality of the critics’ research, noting that several of their rebuttals were rejected for publication in prominent journals.
On one aspect of the debate, Dr. Brown said, the discovery team has backed down. He had proposed that Homo erectus, an immediate predecessor to Homo sapiens, reached Flores 840,000 years ago and, in isolation, evolved into Homo floresiensis.
“I have moved away from the isolation and dwarfing argument,” Dr. Brown has said. “Seems most likely that they arrived small brained and small bodied.”
In their new report, the critics emphasized the facial asymmetry of the single skull specimen, known as LB1. A team member, David W. Frayer of the University of Kansas, composed split photographs of LB1’s face, combining two left or two right sides as composite faces. The dissimilarities between the original face and the two left or right composites were striking, he said.
Although most faces are not perfectly symmetrical, the scientists said, some of the differences in the two sides of the LB1 face exceeded “clinical norms” and “provided evidence for rejecting any contention that the LB1 cranium is developmentally normal.”
Maciej Henneberg, an anatomist at the University of Adelaide, Australia, and an author of the new report, said that many characteristics of the face point to a growth disorder, but that it would require much more research “to diagnose the specific syndrome present.”
Of 184 syndromes that include microcephaly, 57 cause short stature, and some also include facial asymmetry and dental anomalies. The critics said one of the next steps would be for scientists specializing in developmental disorders to join the hunt for the particular syndrome that afflicted at least one, and perhaps more of the extinct little people.
As for the species question, some scientists said it might take DNA tests to place the Floresians securely within the modern human family or somewhere on a slightly separate branch as a separate species.
Q & A: Perils of Plaque
By C. CLAIBORNE RAY, The New York Times, August 22, 2006
Q. Is there any correlation between the plaque that forms on teeth and plaque in the arteries?
A. Quite possibly. Though scientists have not drawn a straight line between the two kinds of plaque, there is a strong correlation between dental disease related to plaque and the incidence of hardening of the arteries, heart disease and stroke.
The association with heart disease is particularly strong in people over 50.
Dental plaque is a bacterial film on the teeth. The most common kind of bacteria found in dental plaque, causing gingivitis and the more severe gum disease called periodontitis, can also escape into the bloodstream.
There, the substances emitted by the bacteria may be implicated in a buildup of arterial deposits or in blood clots, recent research suggests.
Meanwhile, people with very severe gum disease, especially those who have lost some teeth, have been found in some studies to have notably higher rates of stroke caused by plaque in the arteries that serve the brain.
While a link in humans has not been proved, studies in animals have shown that periodontal disease can induce hardening of the arteries, and the plaque bacteria can cause clots in human blood in the test tube.
The theory is that gum disease is part of a chain reaction of inflammatory damage. Now researchers are undertaking studies to see if treating gum disease can ward off heart and artery disease.
Four Are Given Highest Honor in Mathematics
By KENNETH CHANG, The New York Times, August 22, 2006
Grigory Perelman, a reclusive Russian mathematician who solved a key piece in a century-old puzzle known as the Poincaré conjecture, was one of four mathematicians awarded the Fields Medal today.
But Dr. Perelman refused to accept the medal, as he has other honors, and he did not attend the ceremonies at the International Congress of Mathematicians in Madrid.
Sir John Ball, president of the International Mathematical Union, which is holding the conference, told The Associated Press that he did not think Dr. Perelman’s decision to turn down the award was intended as a snub. “I am sure he did not mean it that way,” he said.
The Fields Medal, often described as mathematics’ equivalent to the Nobel Prize, is given every four years, and several can be awarded at once. Three other professors of mathematics were awarded Fields Medals this year: Andrei Okounkov of Princeton; Terence Tao of University of California, Los Angeles; and Wendelin Werner of the University of Paris-Sud in Orsay.
Dr. Perelman, 40, is known not only for his work on the Poincaré conjecture, among the most heralded unsolved math problems, but also because he has declined previous mathematical prizes and has turned down job offers from Princeton, Stanford and other universities. He has said he wants no part of $1 million that the Clay Mathematics Institute in Cambridge, Mass. has offered for the first published proof of the conjecture.
Beginning in 2002, Dr. Perelman, then at the Steklov Institute of Mathematics of the Russian Academy of Sciences in St. Petersburg, published a series of papers on the Internet and gave lectures at several American universities describing how he had overcome a roadblock in the proof of the Poincaré conjecture.
The conjecture, devised by Henri Poincaré in 1904, essentially says that the only shape that has no holes and fits within a finite space is a sphere. That is certainly true looking at two-dimensional surfaces in the everyday three-dimensional world, but the conjecture says the same is true for three-dimensional surfaces embedded in four dimensions.
Dr. Perelman solved a difficult problem that other mathematicians had encountered when trying to prove the conjecture, using a technique called Ricci flow that smoothes out bumps in a surface and transforms it into a simpler form.
Dr. Okounkov, born in 1969 in Moscow, was recognized for work that tied together different fields of mathematics that had seemed unrelated. “This is the striking feature of Okounkovs’s work, finding unexpected links,” said Enrico Arbarello, a professor of geometry at the University of Rome in Italy.
Dr. Okounkov’s work has found use in describing the changing surfaces of melting crystals. The boundary between melted and non-melted is created randomly, but the random process inevitably produces a border in the shape of a heart.
Dr. Tao, a native of Australia and one of the youngest Fields Medal winners ever at age 31, has worked in several different fields, producing significant advances in the understanding of prime numbers, techniques that might lead to simplifying the equations of Einstein’s theory of general relativity and the equations of quantum mechanics that describe how light bounces around in a fiber optic cable.
Dr. Werner, born in Germany in 1968, has also worked at the intersection of mathematics and physics, describing phenomena like percolation and shapes produced by the random paths of Brownian motion.
The medal was conceived by John Charles Fields, a Canadian mathematician, “in recognition of work already done and as an encouragement for further achievements on the part of the recipient.”
Since 1936, when the medal was first awarded, judges have interpreted the terms of Dr. Fields’s trust fund to mean that the award should usually be limited to mathematicians 40 years old or younger.
Concern Mounts as Bacteria Resistant to Antibiotics Disperse Widely
By KATE MURPHY, The New York Times, August 22, 2006
In April 2005, Sara Stephan, a 13-year old in Charleroi, Pa., developed what looked like a pimple on her cheek.
A blemish on a teenager is not exactly cause for alarm, but her mother, Carla Stephan, became concerned when it started to spread and swell. “Her whole cheek got big and red,” she said.
Next, a similar lesion above Sara’s eye. Then, she got one the size of a softball on her buttock, and several more on her thighs.
Tests showed that Sara had a particularly persistent and sometimes deadly bacterial infection known as methicillin-resistant staphylococcus aureus, often abbreviated as M.R.S.A.
Intravenous antibiotics seemed to eradicate it, but Sara has had recurrences, requiring three additional hospitalizations.
“It’s been horrible,” Ms. Stephan said. “How would you feel being her age having to deal with this?”
Health care providers have been concerned about an increasing number of such cases for years. But they are now reporting infections in unexpected locales and among a bewilderingly diverse population.
M.R.S.A. is also demonstrating an alarming virulence and protean nature, making it more difficult to contain and treat. Doctors say that because it is not clear who is vulnerable — even people who are in good health and practice good hygiene have been infected — everyone should take steps to reduce his or her risk.
Although the bacterium has lurked in hospitals for decades, outbreaks elsewhere were virtually unheard of until the 1990’s. Even then, the incidence was small, and the infection was confined mostly to people with weak immune systems: young children, the elderly and people with H.I.V. It occurred mostly in large metropolitan areas.
But in the last five years, the number of cases has drastically increased. “It’s infecting normal, healthy people everywhere,” said Loren G. Miller, a principal investigator at the Los Angeles Biomedical Research Institute at Harbor-U.C.L.A. Medical Center.
Although they do not track the incidence of methicillin-resistant staph nationwide, officials at the federal Centers for Disease Control and Prevention have reported that infection rates have doubled since 2002 in cities like Atlanta and Baltimore, where the agency finances disease surveillance.
Those numbers are probably “lower than reality,” said Rachel Gorwitz, a medical epidemiologist at the agency, because they only represent the cases that have been confirmed by laboratories.
Moreover, small towns in less populated states like Vermont and Montana are now reporting outbreaks.
Staphylococcus aureus can be found almost everywhere: on countertops, in towels and sheets, and on skin. It is harmless until it enters a break in the skin, where it can feed on tissue and multiply.
White blood cells often destroy the bacteria. But sometimes, an antibiotic is needed as reinforcement to prevent the microbes from invading the bloodstream and attacking the vital organs.
Methicillin-resistant staphylococcus aureus, the experts say, is undeterred by most frontline antibiotics, and it is rapidly developing resistance to others.
Evolutionary overachievers, the bacteria “reproduce every 20 minutes, and each time there’s an opportunity for mutation, to select out for resistance,” said Dr. C. Glenn Mayhall, a specialist in infectious diseases at the University of Texas Medical Branch in Galveston.
The overuse of antibiotics has not helped.
“Doctors are prescribing them when it’s inappropriate, and often using more powerful drugs than necessary,” Dr. Mayhall said.
That problem, combined with the widespread prophylactic use of antibiotics in livestock, has given staph, not to mention other bacteria, ample opportunity to evolve into superresistant and superpersistent bugs.
“It’s part natural evolution, but we’re speeding it up by our behaviors,” said Nicole Coffin, a spokeswoman for the C.D.C. Unlike the resistant staph seen in hospitals, many of the strains being reported elsewhere can release a toxin, Panton-Valentine leukocidin, or P.V.L., that kills white blood cells.
“It makes it a double threat and is a huge virulence factor,” said Dr. Robert S. Daum, a professor of pediatrics at the University of Chicago, who has genetically identified more than 100 distinct strains of M.R.S.A. Dr. Daum’s research indicates that in the last five to six years, the proportion of staph infections with the P.V.L. gene has increased, to 90 percent from 5 percent.
“Children that are healthy and playing with their toys in the morning get this infection and are dead that night,” he said.
An example was 2-month-old Madeline Reimer of Plainfield, Ill., who died last year. She was a happy, gurgling baby in the morning, her mother, Beth Reimer, said, and grew so ill that she was airlifted to a hospital in the afternoon. She died after 11 days on life support.
“I still can’t believe it could happen that fast,” Ms. Reimer said. “And we were so cautious because she was premature, not exposing her to crowds or anyone, really, besides her grandparents.”
Also disturbing, doctors say, are infections of resistant staph that mutate into life-threatening necrotizing fasciitis, the so-called flesh-eating bacteria. Such infections had been associated primarily with streptococcal bacteria, which cause strep throat.
M.R.S.A. has also been implicated in fatal cases of meningitis, or swelling of the membranes that cover the brain and spinal cord, and pyomyocitis, which results in abscesses deep in muscle tissue and is more commonly found on tropical islands.
“Things textbooks say don’t happen are happening,” said Dr. Miller, the U.C.L.A. researcher.
About a third of the population in the United States carries staph bacteria in the nose, according to a study by the C.D.C.
The big questions are why some of those people develop infections and others do not, and why some who are infected become ill or even die while others rapidly recover.
“The short answer is we don’t know,” said Dr. Franklin Lowy, a professor of pathology at the College of Physicians and Surgeons of Columbia University and the lead researcher in a study on the spread of resistant staph financed by the National Institutes of Health.
A reason is that the bacteria feed, replicate, mutate and release toxins unpredictably and differently in different people. Sara Stephan, the teenager in Pennsylvania, has had recurrent infections. But her mother was an asymptomatic carrier and her father and 11-year-old brother have had no trace of the bacteria.
Similarly, Madeline Reimer, the infant, died while her twin brother carried the bacteria but never developed an infection. Another brother, 15, tested negative for it. Beth Reimer tested positive as a carrier, and her husband developed an infection that disappeared quickly with oral antibiotics.
Failing to wash thoroughly, and sharing razors, towels or sports equipment increases the odds of exposure and infection, experts say. Tattooing and body waxing also make an infection more likely, because needle punctures or vacant hair follicles give the bacteria more portals of entry.
But the bacteria can also creep into a person’s system through an invisible abrasion from shaving or even a mosquito bite. Being infected can be a matter of “plain old bad luck,” Dr. Miller said.
Another contributing factor may be contact with a worker in a health care institution. Anecdotal evidence from primary care doctors, dermatologists and Internet forums suggest that victims frequently have immediate family members who work in hospitals or clinics.
Researchers say the strains of the bacteria found in hospitals differ genetically from those infecting people in the general population.
“That distinction is no longer valid,” Dr. Lowy said, because so many of the people who are infected outside hospitals are then admitted to them. There, the bacteria can replicate, mutate and return to the public.
Though cleanliness is a good preventive, washing too frequently can also make someone more susceptible. Bathe obsessively, and “you clear a path for more aggressive bacteria like M.R.S.A. to take hold,” said Dr. Stephen K. Tyring, a professor of dermatology at the University of Texas Health Science Center at Houston.
Research also suggests that antibacterial soap is no more effective than regular soap in killing the bacteria, though alcohol-based sanitizing gels kill more bacteria on the hands than soap.
After an infection has begun, antibiotics like clindamycin, minocycline and vancomycin are effective, but they tend to work slowly and can have side effects like rashes, teeth discoloration and severe diarrhea.
When caught early enough, infectious disease experts said, a staph infection can also be treated by a minor surgical incision to drain the lesions, without resorting to oral or intravenous antibiotics.
It is important to see a doctor when a cut, scrape or bump becomes red, large, painful or purulent. Red lines tracking away from the abscess, as well as a fever, indicate that the infection is severe and needs immediate attention.
“Waiting can be deadly,” Dr. Miller said.
By JOHN NOBLE WILFORD, The New York Times, August 22, 2006
After the 18,000-year-old bones of diminutive people were found on the Indonesian island of Flores, the discoverers announced two years ago that these were remains of a previously unknown species of the ancestral human family. They gave it the name Homo floresiensis.
Doubts were raised almost immediately. But only now have opposing scientists from Indonesia, Australia and the United States weighed in with a comprehensive analysis based on their own first-hand examination of the bones and a single mostly complete skull.
The evidence, they reported yesterday, strongly supports their doubts. The discoverers, however, hastened to defend their initial new-species interpretation.
The critics concluded in an article in the current issue of The Proceedings of the National Academy of Sciences that the “little people of Flores,” as they are often called, were not a newfound extinct species.
They were, instead, modern Homo sapiens who resemble pygmies now living in the region and, as suggested in particular by the skull, appear to have been afflicted with the developmental disorder microcephaly, which causes the head and brain to be much smaller than average.
The international team of paleontologists, anatomists and other researchers who conducted the study was headed by Teuku Jacob of Gadjah Mada University, who is one of Indonesia’s senior paleontologists.
In the report, Dr. Jacob and his colleagues cited 140 features of the skull that they said placed it “within modern human ranges of variation.” They also noted features of two jaws and some teeth that “either show no substantial deviation from modern Homo sapiens or share features (receding chins and rotated premolars) with Rampasasa pygmies now living near Liang Bua Cave,” where the discovery was made.
“We have eliminated the idea of a new species,” Robert B. Eckhardt, a professor of developmental genetics at Penn State who was a team member, said in a telephone interview. “After a time, this will be admitted.”
That time has not yet come.
Peter Brown, a paleontologist at the University of New England in Armidale, Australia, who was a leader of the team that discovered the “little people” bones, took sharp issue with the new report.
In an e-mail message, Dr. Brown said, “The authors provide absolutely no evidence that the unique combination of features found in Homo floresiensis are found in any modern humans.”
The features he referred to include body size, body proportions, brain size, receding chin, shape of premolar teeth and their roots, and the shape and projection of the brow ridge. But the critics asserted that many of the features in the specimen with the cranium, said to be diagnostic of a new species, are present in the Rampasasa pygmies.
Dr. Brown said the critics’ claim of “the asymmetry of the skull being the result of abnormal growth is fiction.” The skeleton was buried deep in sediment, he said, and this brought on “some slight distortion.”
In response, Dr. Eckhardt said, “Our paper accounts neatly for everything we see in the asymmetry” of the face and other parts of the skeletons.
Dr. Brown said an independent study led by Debbie Argue, an anthropologist at the Australian National University in Canberra, discounted microcephaly as an explanation. He said the report, accepted for publication in The Journal of Human Evolution, “completely supports my arguments for a new species.”
Dr. Argue’s group, which included Colin Groves, also of the Australian National University and an authority on primate taxonomy, wrote that its comparisons of the Flores specimen with modern and early humans, pygmies and microcephalic humans showed it was unlikely that the skull belonged to a microcephalic human or to any known species.
The bones at the center of the controversy were excavated from a limestone cave on Flores, an island 370 miles east of Bali, by Australian and Indonesian archaeologists.
The most complete specimen was estimated to be 18,000 years old, and other remains of as many as seven other individuals ranged from 95,000 to 13,000 years old.
The Floresian adults stood just three and a half feet high and had brains of 380 cubic centimeters, about the size of the apelike human ancestors known as australopithecines, which lived more than three million years ago.
The find was announced in October 2004 in the journal Nature by a group headed by Michael J. Morwood, also of the University of New England. Dr. Brown was the lead author of a companion report that assigned the little people to a new human species.
In the time since, the dispute over the interpretation has often veered in nonscientific directions, sometimes trampling on national pride.
Indonesian paleontologists complained that the Australian scientists took most of the credit for the discovery and put their own stamp on the interpretations. They were also upset by what they said was the limited access they had to the specimens for their own analysis.
The discoverers countered that the Indonesian researchers had mishandled the bones. They also disparaged the quality of the critics’ research, noting that several of their rebuttals were rejected for publication in prominent journals.
On one aspect of the debate, Dr. Brown said, the discovery team has backed down. He had proposed that Homo erectus, an immediate predecessor to Homo sapiens, reached Flores 840,000 years ago and, in isolation, evolved into Homo floresiensis.
“I have moved away from the isolation and dwarfing argument,” Dr. Brown has said. “Seems most likely that they arrived small brained and small bodied.”
In their new report, the critics emphasized the facial asymmetry of the single skull specimen, known as LB1. A team member, David W. Frayer of the University of Kansas, composed split photographs of LB1’s face, combining two left or two right sides as composite faces. The dissimilarities between the original face and the two left or right composites were striking, he said.
Although most faces are not perfectly symmetrical, the scientists said, some of the differences in the two sides of the LB1 face exceeded “clinical norms” and “provided evidence for rejecting any contention that the LB1 cranium is developmentally normal.”
Maciej Henneberg, an anatomist at the University of Adelaide, Australia, and an author of the new report, said that many characteristics of the face point to a growth disorder, but that it would require much more research “to diagnose the specific syndrome present.”
Of 184 syndromes that include microcephaly, 57 cause short stature, and some also include facial asymmetry and dental anomalies. The critics said one of the next steps would be for scientists specializing in developmental disorders to join the hunt for the particular syndrome that afflicted at least one, and perhaps more of the extinct little people.
As for the species question, some scientists said it might take DNA tests to place the Floresians securely within the modern human family or somewhere on a slightly separate branch as a separate species.
Q & A: Perils of Plaque
By C. CLAIBORNE RAY, The New York Times, August 22, 2006
Q. Is there any correlation between the plaque that forms on teeth and plaque in the arteries?
A. Quite possibly. Though scientists have not drawn a straight line between the two kinds of plaque, there is a strong correlation between dental disease related to plaque and the incidence of hardening of the arteries, heart disease and stroke.
The association with heart disease is particularly strong in people over 50.
Dental plaque is a bacterial film on the teeth. The most common kind of bacteria found in dental plaque, causing gingivitis and the more severe gum disease called periodontitis, can also escape into the bloodstream.
There, the substances emitted by the bacteria may be implicated in a buildup of arterial deposits or in blood clots, recent research suggests.
Meanwhile, people with very severe gum disease, especially those who have lost some teeth, have been found in some studies to have notably higher rates of stroke caused by plaque in the arteries that serve the brain.
While a link in humans has not been proved, studies in animals have shown that periodontal disease can induce hardening of the arteries, and the plaque bacteria can cause clots in human blood in the test tube.
The theory is that gum disease is part of a chain reaction of inflammatory damage. Now researchers are undertaking studies to see if treating gum disease can ward off heart and artery disease.
Four Are Given Highest Honor in Mathematics
By KENNETH CHANG, The New York Times, August 22, 2006
Grigory Perelman, a reclusive Russian mathematician who solved a key piece in a century-old puzzle known as the Poincaré conjecture, was one of four mathematicians awarded the Fields Medal today.
But Dr. Perelman refused to accept the medal, as he has other honors, and he did not attend the ceremonies at the International Congress of Mathematicians in Madrid.
Sir John Ball, president of the International Mathematical Union, which is holding the conference, told The Associated Press that he did not think Dr. Perelman’s decision to turn down the award was intended as a snub. “I am sure he did not mean it that way,” he said.
The Fields Medal, often described as mathematics’ equivalent to the Nobel Prize, is given every four years, and several can be awarded at once. Three other professors of mathematics were awarded Fields Medals this year: Andrei Okounkov of Princeton; Terence Tao of University of California, Los Angeles; and Wendelin Werner of the University of Paris-Sud in Orsay.
Dr. Perelman, 40, is known not only for his work on the Poincaré conjecture, among the most heralded unsolved math problems, but also because he has declined previous mathematical prizes and has turned down job offers from Princeton, Stanford and other universities. He has said he wants no part of $1 million that the Clay Mathematics Institute in Cambridge, Mass. has offered for the first published proof of the conjecture.
Beginning in 2002, Dr. Perelman, then at the Steklov Institute of Mathematics of the Russian Academy of Sciences in St. Petersburg, published a series of papers on the Internet and gave lectures at several American universities describing how he had overcome a roadblock in the proof of the Poincaré conjecture.
The conjecture, devised by Henri Poincaré in 1904, essentially says that the only shape that has no holes and fits within a finite space is a sphere. That is certainly true looking at two-dimensional surfaces in the everyday three-dimensional world, but the conjecture says the same is true for three-dimensional surfaces embedded in four dimensions.
Dr. Perelman solved a difficult problem that other mathematicians had encountered when trying to prove the conjecture, using a technique called Ricci flow that smoothes out bumps in a surface and transforms it into a simpler form.
Dr. Okounkov, born in 1969 in Moscow, was recognized for work that tied together different fields of mathematics that had seemed unrelated. “This is the striking feature of Okounkovs’s work, finding unexpected links,” said Enrico Arbarello, a professor of geometry at the University of Rome in Italy.
Dr. Okounkov’s work has found use in describing the changing surfaces of melting crystals. The boundary between melted and non-melted is created randomly, but the random process inevitably produces a border in the shape of a heart.
Dr. Tao, a native of Australia and one of the youngest Fields Medal winners ever at age 31, has worked in several different fields, producing significant advances in the understanding of prime numbers, techniques that might lead to simplifying the equations of Einstein’s theory of general relativity and the equations of quantum mechanics that describe how light bounces around in a fiber optic cable.
Dr. Werner, born in Germany in 1968, has also worked at the intersection of mathematics and physics, describing phenomena like percolation and shapes produced by the random paths of Brownian motion.
The medal was conceived by John Charles Fields, a Canadian mathematician, “in recognition of work already done and as an encouragement for further achievements on the part of the recipient.”
Since 1936, when the medal was first awarded, judges have interpreted the terms of Dr. Fields’s trust fund to mean that the award should usually be limited to mathematicians 40 years old or younger.
Concern Mounts as Bacteria Resistant to Antibiotics Disperse Widely
By KATE MURPHY, The New York Times, August 22, 2006
In April 2005, Sara Stephan, a 13-year old in Charleroi, Pa., developed what looked like a pimple on her cheek.
A blemish on a teenager is not exactly cause for alarm, but her mother, Carla Stephan, became concerned when it started to spread and swell. “Her whole cheek got big and red,” she said.
Next, a similar lesion above Sara’s eye. Then, she got one the size of a softball on her buttock, and several more on her thighs.
Tests showed that Sara had a particularly persistent and sometimes deadly bacterial infection known as methicillin-resistant staphylococcus aureus, often abbreviated as M.R.S.A.
Intravenous antibiotics seemed to eradicate it, but Sara has had recurrences, requiring three additional hospitalizations.
“It’s been horrible,” Ms. Stephan said. “How would you feel being her age having to deal with this?”
Health care providers have been concerned about an increasing number of such cases for years. But they are now reporting infections in unexpected locales and among a bewilderingly diverse population.
M.R.S.A. is also demonstrating an alarming virulence and protean nature, making it more difficult to contain and treat. Doctors say that because it is not clear who is vulnerable — even people who are in good health and practice good hygiene have been infected — everyone should take steps to reduce his or her risk.
Although the bacterium has lurked in hospitals for decades, outbreaks elsewhere were virtually unheard of until the 1990’s. Even then, the incidence was small, and the infection was confined mostly to people with weak immune systems: young children, the elderly and people with H.I.V. It occurred mostly in large metropolitan areas.
But in the last five years, the number of cases has drastically increased. “It’s infecting normal, healthy people everywhere,” said Loren G. Miller, a principal investigator at the Los Angeles Biomedical Research Institute at Harbor-U.C.L.A. Medical Center.
Although they do not track the incidence of methicillin-resistant staph nationwide, officials at the federal Centers for Disease Control and Prevention have reported that infection rates have doubled since 2002 in cities like Atlanta and Baltimore, where the agency finances disease surveillance.
Those numbers are probably “lower than reality,” said Rachel Gorwitz, a medical epidemiologist at the agency, because they only represent the cases that have been confirmed by laboratories.
Moreover, small towns in less populated states like Vermont and Montana are now reporting outbreaks.
Staphylococcus aureus can be found almost everywhere: on countertops, in towels and sheets, and on skin. It is harmless until it enters a break in the skin, where it can feed on tissue and multiply.
White blood cells often destroy the bacteria. But sometimes, an antibiotic is needed as reinforcement to prevent the microbes from invading the bloodstream and attacking the vital organs.
Methicillin-resistant staphylococcus aureus, the experts say, is undeterred by most frontline antibiotics, and it is rapidly developing resistance to others.
Evolutionary overachievers, the bacteria “reproduce every 20 minutes, and each time there’s an opportunity for mutation, to select out for resistance,” said Dr. C. Glenn Mayhall, a specialist in infectious diseases at the University of Texas Medical Branch in Galveston.
The overuse of antibiotics has not helped.
“Doctors are prescribing them when it’s inappropriate, and often using more powerful drugs than necessary,” Dr. Mayhall said.
That problem, combined with the widespread prophylactic use of antibiotics in livestock, has given staph, not to mention other bacteria, ample opportunity to evolve into superresistant and superpersistent bugs.
“It’s part natural evolution, but we’re speeding it up by our behaviors,” said Nicole Coffin, a spokeswoman for the C.D.C. Unlike the resistant staph seen in hospitals, many of the strains being reported elsewhere can release a toxin, Panton-Valentine leukocidin, or P.V.L., that kills white blood cells.
“It makes it a double threat and is a huge virulence factor,” said Dr. Robert S. Daum, a professor of pediatrics at the University of Chicago, who has genetically identified more than 100 distinct strains of M.R.S.A. Dr. Daum’s research indicates that in the last five to six years, the proportion of staph infections with the P.V.L. gene has increased, to 90 percent from 5 percent.
“Children that are healthy and playing with their toys in the morning get this infection and are dead that night,” he said.
An example was 2-month-old Madeline Reimer of Plainfield, Ill., who died last year. She was a happy, gurgling baby in the morning, her mother, Beth Reimer, said, and grew so ill that she was airlifted to a hospital in the afternoon. She died after 11 days on life support.
“I still can’t believe it could happen that fast,” Ms. Reimer said. “And we were so cautious because she was premature, not exposing her to crowds or anyone, really, besides her grandparents.”
Also disturbing, doctors say, are infections of resistant staph that mutate into life-threatening necrotizing fasciitis, the so-called flesh-eating bacteria. Such infections had been associated primarily with streptococcal bacteria, which cause strep throat.
M.R.S.A. has also been implicated in fatal cases of meningitis, or swelling of the membranes that cover the brain and spinal cord, and pyomyocitis, which results in abscesses deep in muscle tissue and is more commonly found on tropical islands.
“Things textbooks say don’t happen are happening,” said Dr. Miller, the U.C.L.A. researcher.
About a third of the population in the United States carries staph bacteria in the nose, according to a study by the C.D.C.
The big questions are why some of those people develop infections and others do not, and why some who are infected become ill or even die while others rapidly recover.
“The short answer is we don’t know,” said Dr. Franklin Lowy, a professor of pathology at the College of Physicians and Surgeons of Columbia University and the lead researcher in a study on the spread of resistant staph financed by the National Institutes of Health.
A reason is that the bacteria feed, replicate, mutate and release toxins unpredictably and differently in different people. Sara Stephan, the teenager in Pennsylvania, has had recurrent infections. But her mother was an asymptomatic carrier and her father and 11-year-old brother have had no trace of the bacteria.
Similarly, Madeline Reimer, the infant, died while her twin brother carried the bacteria but never developed an infection. Another brother, 15, tested negative for it. Beth Reimer tested positive as a carrier, and her husband developed an infection that disappeared quickly with oral antibiotics.
Failing to wash thoroughly, and sharing razors, towels or sports equipment increases the odds of exposure and infection, experts say. Tattooing and body waxing also make an infection more likely, because needle punctures or vacant hair follicles give the bacteria more portals of entry.
But the bacteria can also creep into a person’s system through an invisible abrasion from shaving or even a mosquito bite. Being infected can be a matter of “plain old bad luck,” Dr. Miller said.
Another contributing factor may be contact with a worker in a health care institution. Anecdotal evidence from primary care doctors, dermatologists and Internet forums suggest that victims frequently have immediate family members who work in hospitals or clinics.
Researchers say the strains of the bacteria found in hospitals differ genetically from those infecting people in the general population.
“That distinction is no longer valid,” Dr. Lowy said, because so many of the people who are infected outside hospitals are then admitted to them. There, the bacteria can replicate, mutate and return to the public.
Though cleanliness is a good preventive, washing too frequently can also make someone more susceptible. Bathe obsessively, and “you clear a path for more aggressive bacteria like M.R.S.A. to take hold,” said Dr. Stephen K. Tyring, a professor of dermatology at the University of Texas Health Science Center at Houston.
Research also suggests that antibacterial soap is no more effective than regular soap in killing the bacteria, though alcohol-based sanitizing gels kill more bacteria on the hands than soap.
After an infection has begun, antibiotics like clindamycin, minocycline and vancomycin are effective, but they tend to work slowly and can have side effects like rashes, teeth discoloration and severe diarrhea.
When caught early enough, infectious disease experts said, a staph infection can also be treated by a minor surgical incision to drain the lesions, without resorting to oral or intravenous antibiotics.
It is important to see a doctor when a cut, scrape or bump becomes red, large, painful or purulent. Red lines tracking away from the abscess, as well as a fever, indicate that the infection is severe and needs immediate attention.
“Waiting can be deadly,” Dr. Miller said.