Science Tuesday - It's a BIG ONE!
Dec. 14th, 2010 03:47 pm![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
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Study of Baby Teeth Sees Radiation Effects
By MATTHEW L. WALD, The New York Times, December 13, 2010
Men who grew up in the St. Louis area in the early 1960s and died of cancer by middle age had more than twice as much radioactive strontium in their baby teeth as men born in the same area at the same time who are still living, according to a study based on teeth collected years ago by Washington University in St. Louis.
The study, published on Dec. 1 in The International Journal of Health Services, analyzed baby teeth collected during the era when the United States and the Soviet Union were conducting nuclear bomb tests in the atmosphere. The study seeks to help scientists determine the health effects of small radiation doses, and to say how many people died from bomb fallout. There is very little reliable data on the relationship of radiation to cancer at low doses, so scientists instead use extrapolations from higher doses, which introduces large uncertainties into their calculations.
The study implies that deaths from bomb fallout globally run into the “many thousands,” said the authors, Joseph J. Mangano and Dr. Janette D. Sherman, both of the Radiation and Public Health Project, nonprofit research group based in New York.
However, a scientist with long experience in the issue, Kevin D. Crowley, the senior board director of the Nuclear and Radiation Studies Board at the National Research Council, urged caution in interpreting the findings.
“It sounds like the best you could do is say this is an association,” he said. “An association is not necessarily causative.”
R. William Field, an epidemiologist at the University of Iowa, praised the authors for exploring the association between fallout in teeth and cancer, but he that said the sample size was too small and that the study had other limitations. He called for follow-ups.
The study’s authors had previously tried to link strontium in the teeth of children growing up near nuclear power plants to releases from those plants, but those findings have not met with much scientific acceptance. Strontium levels in a person’s body may have more to do with where the person’s food was farmed than with where the person lives. In addition, the Nuclear Regulatory Commission calculated that the doses from radioactive strontium in the environment add only about 0.3 percent to the average American’s background exposure.
But this study tries to link differences in tooth contamination more directly with health outcomes. The study measured the ratio of calcium, a basic building block of teeth and bones, to strontium 90, which is absorbed just as calcium is. The authors said they were using strontium as a proxy for all long-lived fallout components, and they picked boys born in a period when there was a lull in atmospheric testing, so that the boys’ exposure to short-lived radioactive materials, in utero or in the first few months of life, was minimized. They limited their research to boys because men seldom change their names and thus were easier to trace.
The authors found that among 3,000 tooth donors, born in 1959, 1960 or the first half of 1961, 84 had died, 12 of those from cancer. The authors selected two “control” cases, people still living, for each of those who had died. The controls were born in the same county, within 40 days of the person who later died. The study compared incisors with incisors, and molars with molars.
The people who would later die of cancer had an average of 7.0 picocuries of per gram of tooth; the control cases, who have never had cancer, had an average of 3.1 picocuries per gram.
But the picture is not completely clear. Measurements of the teeth of people who later had cancer but survived it did not show strontium levels markedly different from those who had never had cancer, according to the study. One reason may be that those nonfatal cancers were often polyps and melanomas not related to radiation.
Rings in Sky Leave Alternate Visions of Universes
By DENNIS OVERBYE, The New York Times, December 13, 2010
Last month a pair of physicists startled the world by claiming that they had managed to see through the Big Bang and glimpse evidence of previous incarnations of the universe in an analysis of radio signals from the sky.
The evidence, said Roger Penrose of Oxford University and Vahe Gurzadyan of Yerevan State University in Armenia, takes the form of concentric rings caused by the collisions of supermassive black holes in earlier versions of our universe and imprinted, like ripples on a pond, on a haze of microwave radiation widely thought to be left over from the Big Bang that started our own cycle of time about 13.7 billion years ago.
Now, however, two other groups of astronomers looking at the same data have concluded that the rings, though real, are part of the current universe we already know and love.
The cosmic microwave background, as it is known, has been much scrutinized since its discovery in 1965 by radio telescopes, balloons and three satellites — NASA’s Cosmic Background Explorer and Wilkinson Microwave Anisotropy Probe satellites and, most recently, Europe’s Planck satellite — for clues to the origin of the universe. Slight temperature deviations in what is otherwise an exceedingly uniform heat bath are thought to arise from microscopic fluctuations in a force field known as inflation that drove the expansion of the universe when it was but a sliver of a nanosecond old.
The rings seen by Dr. Penrose and Dr. Gurzadyan are thin bands in which the noisy pattern of heat and cold in the early universe, as recorded by the Wilkinson satellite and other experiments, is slightly less splotchy than normal. They posted a copy of their paper on the Internet on Nov. 16, noting that the rings confirmed a prediction of a theory recently proposed by Dr. Penrose, one of the world’s distinguished mathematicians, called Conformal Cyclic Cosmology. It is the subject of a new book by him, “Cycles of Time: An Extraordinary New View of the Universe,” due out in May from Knopf.
Mainstream cosmologists, who have seen a long list of anomalies in the cosmic background come and go, were not impressed. Now their skepticism is supported by two groups of cosmologists, Ingunn Kathrine Wehus and Hans Eriksen of the University of Oslo in Norway and Adam Moss, Douglas Scott and James P. Zibrin, all of the University of British Columbia. In separate papers based on data from the Wilkinson satellite, both groups reported finding such rings, but said the rings were consistent with having arisen by chance in the earliest moments of our own universe. Eternity is not needed to explain them.
Dr. Moss and his colleagues wrote, “Gurzadyan and Penrose have not found evidence for pre-Big Bang phenomena, but have simply rediscovered that the CMB contains structure.”
David Spergel, a Princeton University astrophysicist and one of the members of the Wilkinson satellite team, said in a e-mail message: “While it would have been exciting to see circles from the pre-Big Bang universe, I view this as science at its best. Exciting claims are made and they draw the attention of cosmologists throughout the world. Because the WMAP data is publicly available, groups throughout the world were able to check the claim. A universe with dark matter, dark energy and inflation is bizarre enough — we don’t, however, get to detect circles from alternative universes.”
But visions of alternative universes keep coming. On Thursday, an international group led by Stephen M. Feeney of University College, London, reported that they had found tentative evidence of blobs in the microwave data that could be bruises from collisions with other universes that bubbled off from our own during the inflation epoch. The evidence, they acknowledged, was too weak to get excited about yet, but could be improved by the Planck satellite, now scanning the sky and expected to report its results in 2012.
“If this evidence is corroborated by upcoming data from the Planck satellite, we will be able to gain insight into the possible existence of the multiverse,” the authors wrote.
Dr. Spergel and Max Tegmark, a cosmologist at M.I.T., both said the group seemed to have done a careful job of analysis. Dr. Tegmark said, “This is going on the list of things people will be majorly looking for in the Planck data.”
This article has been revised to reflect the following correction:
Correction: December 14, 2010
In an earlier version of this article, the picture caption may have left the misleading impression that concentric circular patterns in microwave radiation are clearly visible in satellite data. The image was modified by researchers to highlight what they see as evidence of black hole collisions in earlier versions of our universe.
Anthropology Group Tries to Soothe Tempers After Dropping the Word ‘Science’
By NICHOLAS WADE, The New York Times, December 13, 2010
The battle of the anthropologists — those who hew closely to scientific tradition versus those who take a more humanistic approach — flared again Monday, as the organization that represents both sides tried to patch things up.
The American Anthropological Association had caused a stir by dropping the word “science” from its long-range plan, angering the evidence-based anthropologists who worry about their field’s growing too soft. All three mentions of the word “science” were excised, and two were replaced by the phrase “the public understanding of humankind.”
On Monday, the association issued a statement of clarification, saying it recognizes “the crucial place of the scientific method in much anthropological research.”
Damon Dozier, the association’s director of public affairs, said: “We’ve heard loud and clear from our members that they have concerns about the long-range plan. We’ll look at the words again.”
The association is an umbrella group that includes several disciplines ranging from physical anthropology — like the study of fossilized human skulls — to more interpretive subjects, like research on race and sex. There has been a longstanding cultural gap within the association between the evidence-based researchers, who include some social anthropologists, and those more interested in advocating for the rights of women or native peoples. The new long-range plan, approved last month, inflamed these differences.
In Monday’s statement, the association defined anthropology as “a holistic and expansive discipline that covers the full breadth of human history and culture.” Anthropology draws on the methods of both the humanities and the sciences, it added.
Mr. Dozier said, “We mean holistic in terms of the diversity of the discipline.”
Peter N. Peregrine, president of the Society for Anthropological Sciences, an affiliate of the association, said Monday that he had heard “outrage and tremendous concern” from his members about dropping references to science, some of them asking how they could justify their department’s existence if their national organization did not regard anthropology as a science.
But Mr. Peregrine expressed hope regarding Monday’s statement, interpreting “holistic” to mean that science is included in the anthropological understanding of human beings.
The differences between the humanistic and scientific approaches may, however, be too large to be bridged. “I really don’t see how or why anthropology should entail humanities,” said Frank Marlowe, president-elect of the Evolutionary Anthropology Society, another association affiliate, given that the social sciences are empirical, while the humanities are analytic, critical or speculative.
“We evolutionary anthropologists are outnumbered by the new cultural or social anthropologists, many but not all of whom are postmodern, which seems to translate into antiscience,” Dr. Marlowe said.
Musk Oxen Live to Tell a Survivors’ Tale
By NATALIE ANGIER, The New York Times, December 13, 2010
Among the various large, charismatic and visibly winterized mammals that one might choose as a mascot for life in the Arctic belt, polar bears are, let’s face it, too hackneyed, reindeer too Rudolph, caribou too Sarah Palin’s target practice, and woolly mammoths too extinct.
There’s a better choice, though few may have heard of it. According to Arctic biologists, the quintessential example of megafaunal fortitude in the face of really bad weather is the musk ox, or Ovibos moschatus, a blocky, short-legged, highly social ungulate with distinctively curved horns and long hair that looks like shag carpeting circa 1975.
Ovibos’s common name is only partly justified. The males do emit a musky cologne during mating season, but the animal is not an ox. Nor, despite its back-of-the-nickel silhouette, is it a type of buffalo either. Its closest living relations are thought to be goats and sheep, but taxonomically and metaphorically, the musk ox is in an icy cubicle of its own. Once abundant throughout the northern latitudes worldwide, today they are found only in Arctic North America, Greenland and pockets of Siberia and Scandinavia. The musk ox is a holdover from the Pleistocene, the age of the giant mammals memorialized in natural history murals everywhere — the mammoths and mastodons, the saber-toothed cats, the giant ground sloths, the 400-pound beavers. Yet while a vast majority of the frost-fitted bigfoots disappeared at the end of the last ice age, 10,000 years ago, Ovibos hung on, as stubbornly as the ox it is not.
Scientists are now seeking to understand how, exactly, the animal has managed to persist through repeated climate shifts and habitat upheavals. Researchers see in the musk ox’s story clues to help guide efforts to conserve other large land mammals now at risk of extinction. They also hope to raise the profile of a species they consider magnificent, at once stalwart and supple, a page of living prehistory whose social and behavioral complexities they have just begun to decode.
“There’s evidence that they have an elephantlike social structure, and even some form of culture,” said Joel Berger, a researcher with the Wildlife Conservation Society and a professor at the University of Montana. So why is everybody flying to Africa to see elephants when we’ve got this marvelous species living in our own backyard?
In a presentation last week at the Bronx Zoo, where the wildlife society is based, Dr. Berger described preliminary results from field studies of the musk ox that he has performed with Layne Adams of the U.S. Geological Survey and other collaborators. He talked about the challenges of catching animals to weigh and measure them, check their teeth, take their blood and furnish them with G.P.S. collars. One group of musk ox in Cape Krusenstern National Monument in Alaska had such bad, broken teeth you’d think they were subsisting on a diet of Pepsi and Snickers bars, said Dr. Berger, and the researchers worried that the population was unhealthy and on its way out.
Yet after suffering several seasons of declining numbers, the brown-toothers rebounded this year to match in fecundity and offspring survival a group living in the Bering Land Bridge National Preserve that had exemplary teeth. The cause of their rotten dentition remains a mystery, but the Krusenstern clan clearly was not biting the dust.
For all their storied past as co-prancers with mastodons, musk oxen are not huge animals. Adult males stand about four feet high and weigh around 600 to 700 pounds, less than half the weight of the average draft horse. Yet they look hulky as a result of their spectacular double-layered fur coat. The long, shaggy outer layer they keep year round, not only to help shield them against the brutal cold of an Arctic winter, when temperatures can plunge 40 degrees or more below zero, but also to deter the insect pests of an Arctic summer.
“You’ll see caribou in summertime trotting across the countryside trying to get away from all the mosquitoes and biting flies,” said Jim Lawler, a biologist with the National Park Service’s Arctic Network in Fairbanks. “But the musk ox just stand there with clouds of mosquitoes hovering above them. It’s hard to penetrate that fur.” For added insulation, musk oxen grow a second fur layer each winter, an undercoat called qiviut that is said to be many times warmer than wool and softer than cashmere — and how obliging of the animals to shed that qiviut in spring for use in scarves.
With their stubby legs, musk oxen are not migratory like caribou or great dashers like reindeer. Their basic approach to winter management is: Don’t just do something — stand there. “You’ll see them in a big storm, drifted over, covered with snow,” said Dr. Lawler. “They’re almost part of the scenery.” They lapse into a state of what might be called hibernation al fresco, as their oxygen consumption and carbon dioxide production drop and their metabolic rate slows by about a third. “They’re basically shutting down some of their machinery so they can survive on less food,” said Dr. Lawler, who has studied musk ox energetics.
Whatever their occasional resemblance to the scenery, musk oxen are by no means as dumb as a post. “They live in loosely knit family-bonded societies,” said Dr. Berger, and they keep track of who’s who. The group is, after all, essential to their survival. When confronted with predators like wolves, a herd of musk oxen will famously circle the wagons, the adults forming a wall of horns facing outward, the vulnerable young safely shielded behind them. They also seem to have a keen memory for where the best foraging grounds may be found in the spring, the optimal mix of grasses and willow twigs to maximize the performance of the microbes at work in their ruminant gut. Musk oxen turn out to be very efficient at extracting calories to put on the fat they need to survive the long winter fast.
Historical records and genetic evidence alike suggest that the musk ox is a Rasputin, “the comeback kid of the Quaternary,” said Ross MacPhee, curator of vertebrate zoology at the American Museum of Natural History. “They undergo periods where they really bolster their numbers for a few years, then they go down to an almost complete collapse, then later they come back like gangbusters.”
As a result of passing through repeated population bottlenecks, in which only a handful of individuals survived to spawn subsequent generations, today’s 100,000 musk oxen are thought to be notably homogenous, lacking in the sort of genetic diversity once thought critical to a species’ long-term prospects. “It would be hard to argue that musk ox are on their way out the door,” said Dr. MacPhee. “They are not weak sisters.”
Just ask that saber-toothed cat fossilized under the floor.
Poisoned Debate Encircles a Microbe Study’s Result
By DENNIS OVERBYE, , The New York Times, December 13, 2010
The announcement that NASA experimenters had found a bacterium that seems to be able to subsist on arsenic in place of phosphorus — an element until now deemed essential for life — set off a cascading storm of criticism on the Internet, first about alleged errors and sloppiness in the paper published in Science by Felisa Wolfe-Simon and her colleagues, and then about their and NASA’s refusal to address the criticisms.
The result has been a stormy brew of debate about the role of peer review, bloggers and the reliability of NASA, at least as it pertains to microbiological issues, almost as toxic as the salty and arsenic waters of Mono Lake in California, from which Dr. Wolfe-Simon of the U.S. Geological Survey scooped up some bacteria last year.
Seeking evidence that life could follow a different biochemical path than what is normally assumed, Dr. Wolfe-Simon grew them in an arsenic-rich and phosphorus-free environment, reporting in the paper and a NASA news conference on Dec. 2 that the bacterium, strain GFAJ-1 of the Halomonadaceae family of Gammaproteobacteria, had substituted arsenic for phosphorus in many important molecules in its body, including DNA.
But the ink had hardly dried on headlines around the world when microbiologists, who have been suspicious of NASA ever since the agency announced that it had found fossils of microbes in a meteorite from Mars in 1996, began shooting back, saying the experimenters had failed to provide any solid evidence that arsenic had actually been incorporated into the bacterium’s DNA.
In a scathing commentary on her blog RRResearch, Rosie Redfield, a microbiologist at the University of British Columbia, in Vancouver, ran through a long list of what she said were errors and omissions in the paper, which she summarized in the end as “lots of flim-flam, but very little reliable information.”
Among other mistakes, she and others say, the experimenters failed to wash the bug’s DNA before testing it for arsenic, thus leaving the possibility that the arsenic detected there was just stuck to the outside of the giant molecule, like mud on the bottom of a shoe, a process she described as “Microbiology 101.” Over the course of a week her blog, which normally has a few hundred visitors a day, recorded almost 90,000 hits before the furor died down. She has also sent a letter to Science.
Things got nastier when NASA and Dr. Wolfe-Simon refused to respond to such criticisms, which quickly leapt from Dr. Redfield and others’ blogs to Wired and Slate and The Observatory, a blog covering the science press for the Columbia Journalism Review. According to CBC News, Dwayne Brown, a NASA spokesman, said that the agency wouldn’t debate science with bloggers and would stick to peer-reviewed literature. The online tech magazine Gizmodo ran a highly doctored picture of Dr. Redfield and Dr. Wolfe-Simon staring lightning bolts at each other.
In a statement on her own Web site, Dr. Wolfe-Simon noted that the paper had been carefully peer-reviewed and said, “We’ve been concerned that some conclusions have been drawn based on claims not made in our paper,” but did not elaborate on what those mistaken claims were.
In the interest of stimulating healthy debate, she said, Science was making the paper available free of charge (although registration is required) for a couple of weeks. The experimenters are compiling a list of answers for frequently asked questions, which can be sent to gfajquestions@gmail.com and will eventually be posted online.
Dr. Redfield said Mr. Brown’s reaction was silly. “We are the peers,” she said.
Conversation and arguing have always been an important part of how science has been done, she said. Once upon a time it was by mail, and was private and slow. “Now,” she said, “the conversation is carried out in public in ways everyone can see.”
She added, “This kind of intellectual analysis and give and take is a big chunk of the fun of doing science.”
Nevertheless, she said she sympathized with Dr. Wolfe-Simon’s position as a woman in science advocating a controversial view, and she agreed with her decision to keep a low peer-reviewed profile. More arguing, as a blogger who goes by the name of Isis pointed out in a post titled “Don’t Like Arsenic Bacteria? Put Your Experiment Where Your Mouth Is!,” will not solve the problem.
Only more data, which will probably be forthcoming, will tell whether the GFAJ-1 bug is weird life that has found a new way to live, or just tough and able to survive in arsenic. If the original paper was right, that would be “great,” said Dr. Redfield. But the opposite could also be presented as a demonstration that life is such a powerful force.
“NASA can spin it either way,” she said.
In a Single-Cell Predator, Clues to the Animal Kingdom’s Birth
By SEAN B. CARROLL, The New York Times, December 13, 2010
The Environmental Protection Agency is worried about a lot of things in our water — polychlorinated biphenyls, dibromochloropropane, Cryptosporidium parvum — to name just a few of the dozens of chemicals or organisms they monitor. However, in nearly every creek and lake, and throughout the oceans, there is one important group of multisyllabic microbes that the E.P.A. does not track, and until recently, most biologists heard and knew very little about — the choanoflagellates.
Before you spit out that glass of water or dunk your swimsuit in Clorox, relax. These tiny organisms are harmless. They are important for other reasons. They are part of the so-called nanoplankton and play critical roles in the ocean food chain. Choanoflagellates are voracious single-cell predators.
The beating of their long flagellum both propels them through the water and creates a current that helps them to collect bacteria and food particles in the collar of 30 to 40 tentaclelike filaments at one end of the cell.
There can be thousands to millions of choanoflagellates in a gallon of sea water, which may filter 10 to 25 percent of coastal surface water per day. Choanoflagellates in turn serve as food for planktonic animals like crustacean larvae, which are consumed by larger animals, and so on up the food chain.
Theirs is a humble existence compared with the larger, more charismatic residents of the oceans like lobsters, fish, squids and whales.
But recent studies suggest that these obscure organisms are among the closest living single-celled relatives of animals. In other words, choanoflagellates are cousins to all animals in the same way that chimpanzees are cousins to humans. Just as the study of great apes has been vital to understanding human evolution, biologists are now scrutinizing choanoflagellates for clues about one of the great transitions in history — the origin of the animal kingdom.
For most of the first 2.5 billion years of life on Earth, most species were microscopic, rarely exceeding one millimeter in size, and unicellular. Many different kinds of larger life forms, including fungi, animals and plants, subsequently evolved independently from separate single-celled ancestors.
The evolution of multicellularity was a critical step in the origin of each of these groups because it opened the way to the emergence of much more complex organisms in which different cells could take on different tasks. And the emergence of larger organisms drove profound changes in ecology that changed the face of the planet.
Scientists are eager to understand how transitions from a unicellular to multicellular lifestyle were accomplished. Reconstructing events that happened more than 600 million years ago, in the case of animals, is a great challenge. Ideally, one would have specimens from just before and immediately after the event. But the unicellular ancestor of animals and those first animals are long extinct. So information has to be gleaned from living sources.
This is where comparisons between choanoflagellates and animals come into play. The close kinship between choanoflagellates and animals means that there once lived a single-celled ancestor that gave rise to two lines of evolution — one leading to the living choanoflagellates and the other to animals. Choanoflagellates can tell us a lot about that ancestor because any characteristics that they share with animals must have been present in that ancestor and then inherited by both groups. By similar logic, whatever animals have but choanoflagellates lack probably arose during animal evolution.
There are striking physical resemblances between choanoflagellates and certain animal cells, specifically the feeding cells of sponges, called choanocytes. Sponge choanocytes also have a flagellum and possess a collar of filaments for trapping food. Similar collars have been seen on several kinds of animals cells. These similarities indicate that the unicellular ancestor of animals probably had a flagellum and a collar, and may have been much like a choanoflagellate.
But even more surprising and informative resemblances between choanoflagellates and animals have been revealed at the level of DNA. Recently, the genome sequence of one choanoflagellate species was analyzed by a team led by Nicole King and Daniel Rokhsar at the University of California, Berkeley. They identified many genetic features that were shared exclusively between choanoflagellates and animals. These included 78 pieces of proteins, many of which in animals are involved in making cells adhere to one another.
The presence of so many cell adhesion molecules in choanoflagellates was very surprising. The scientists are trying to figure out what all of those molecules are doing in a unicellular creature. One possibility is that the molecules are used in capturing prey.
Whatever the explanation, the presence of those genes in a unicellular organism indicates that much of the machinery for making multicellular animals was in place long before the origin of animals. It may be that rather than evolving new genes, animal ancestors simply used what they had to become multicellular. There may be selective advantages to forming colonies, like avoiding being eaten by other small predators. And in fact, some choanoflagellates do form multicellular colonies at stages of their life cycle.
Dr. King and her colleagues Stephen Fairclough and Mark Dayel investigated one such species to determine whether colony formation occurred by dividing cells staying together, the way animal embryos form, or by individual cells aggregating together, as some protists like slime molds do.
The scientists found that colonies formed exclusively by dividing cells staying together. They suggested that the ancient common ancestor of choanoflagellates and animals was capable of forming simple colonies and that this property may well have been a first step on the road to animal evolution.
The world is full of microbes, and we spend a lot of worry and effort trying to keep them off and out of our bodies. It is humbling to ponder that still swimming within that microscopic soup are our distant cousins.
This article has been revised to reflect the following correction:
Correction: December 14, 2010
An earlier version of this article misspelled the surname of a researcher at the University of California, Berkeley. He is Mark Dayel, not Doyel. And a credit for a picture of feeding cells of sponges misspelled the photographer's surname. He is Scott Nichols, not Nichol.
Birds Do It ... We Do It ... and No One Knows Why
By NICHOLAS BAKALAR, The New York Times, December 13, 2010
Everyone yawns, but no one knows why. We start when we are in the womb, and we do it through old age. Most vertebrate species, even birds and fishes, yawn too, or at least do something that looks very much like it. But its physiological mechanisms, its purpose and what survival value it might have remain a mystery.
There is no shortage of theories — a recent article in the journal Neuroscience & Biobehavioral Reviews outlines many — but a dearth of experimental proof that any of them is correct.
“The lack of experimental evidence is sometimes accompanied by passionate discussion,” said Dr. Adrian G. Guggisberg, the lead author.
Hippocrates proposed in the fourth century B.C. that yawning got rid of “bad air,” and increased “good air” in the brain. The widely held modern view of this theory is that yawning helps increase blood oxygen levels and decrease carbon dioxide.
If this were true, Dr. Guggisberg writes, then people would yawn more when they exercise. And people with lung or heart disease, who often suffer from a lack of oxygen, yawn no more than anyone else.
Researchers have exposed healthy subjects to gas mixtures with high levels of carbon dioxide and found that it does not lead to increased yawning. In fact, there is no study that shows that oxygen levels in the brain are changed one way or the other by yawning.
In other words, observation and experiment suggest that the best way to increase blood oxygen levels is not yawning, but rapid breathing.
There is no question that yawning occurs most frequently before and after sleep, and the subjective feeling of drowsiness accompanies increased yawning. So maybe yawning helps keep us awake.
Researchers tested this hypothesis by inducing yawning in human subjects and then observing brain activity with encephalography as they yawned. The EEG produced no evidence that yawning increased vigilance in the brain or central nervous system.
Some researchers have suggested the opposite — that yawning lowers arousal and helps us go to sleep. But even though yawning and drowsiness occur together, no experiment has shown a causal connection between the two.
Could the purpose of yawning be regulation of body heat? Researchers have shown that contagious yawns (induced with yawning videos) can be decreased when a cold pack is placed on the forehead, and increased with a warm pack. But the experiment, Dr. Guggisberg says, did not control for other factors — a nice warm pack is likely to increase drowsiness, and a cold pack to increase wakefulness, making it impossible to determine the effect of temperature.
While Dr. Guggisberg finds the evidence for the thermal regulation theory inconclusive, Andrew C. Gallup, a postdoctoral fellow at Princeton, disagrees.
“In rat experiments, yawning is preceded by rapid increases in brain temperature and following the yawning a return to lower temperatures,” he said. “That suggests an association with a thermoregulatory function, although it can’t be interpreted as causal.”
Dr. Gallup outlines his position in an article accepted for publication in Neuroscience & Biobehavioral Reviews, the same journal in which Dr. Guggisberg’s review appears.
Another theory is that yawning helps equalize pressure in the middle ear with outside air pressure. But that function can be fulfilled by other techniques — chewing or swallowing — so there is no reason to believe that yawning has an essential evolutionary advantage. And there is no evidence that yawning increases with air pressure changes.
So what purpose does yawning serve?
Children under 5 are not subject to contagious yawning, but adult humans, chimpanzees, monkeys and dogs — animals with advanced social skills — are. Apparently an understanding of the mental states of others is required before yawning becomes catching.
That idea is supported by M.R.I. observation in humans: watching others yawn activates brain regions related to imitation, empathy and social behavior.
For Dr. Guggisberg, this social interpretation is the only one that appears to account for all the aspects of the phenomenon. But Dr. Gallup points out that solitary species yawn, too, and that chimpanzees and humans yawn when they are alone.
Dr. Gallup conceded that yawning might have some social function in some species. But he said, “Any social function that it has would be a derived feature, and not a more primitive underlying feature of the behavior.”
Dr. Guggisberg, a researcher at the University of Geneva, offered a conclusion that few experts will find objectionable. “Yawning,” he said “is a very rich and complex phenomenon.”
Rare Albatross Expands Its Breeding Grounds
By SINDYA N. BHANOO, The New York Times, December 13, 2010
Two pairs of the short-tailed albatross, thought to remain only on two Japanese islands, have been found nesting on Kure Atoll and on Midway Atoll, American wildlife refuges in the Hawaiian Islands.
Until now, the last remaining breeding colonies of the birds were thought to have been on the Japanese islands. The total adult population of the species is only about 3,000.
The new finding brings hope that the bird might propagate beyond Japan, said Jessica Hardesty Norris, director of the Seabird Program at the American Bird Conservancy, a conservation organization.
“Where they breed in Japan is a pretty decent habitat, but there’s a really active and nasty volcano,” she said. “It could wipe out the species, so we are excited about the prospect of another viable colony.”
The short-tailed albatross is a striking bird, with a bright pink bill, a white body and a golden-colored crown and nape.
Although the bird once thrived in the islands of the Pacific Ocean, the appeal of its feathers for hats and other decorative purposes led to a drop in population in the late 19th century.
Some breeding grounds in Torishima, Japan, were damaged in a volcanic eruption in 1939, and the number of nesting pairs fell to about 10.
The birds that were recently found include one male-female pair, with a fertilized egg, and one female-female pair with two eggs. It is still unclear whether the eggs of the same-sex pair are fertilized.
Using Waste, Swedish City Cuts Its Fossil Fuel Use
By ELISABETH ROSENTHAL, , The New York Times, December 13, 2010
KRISTIANSTAD, Sweden — When this city vowed a decade ago to wean itself from fossil fuels, it was a lofty aspiration, like zero deaths from traffic accidents or the elimination of childhood obesity.
But Kristianstad has already crossed a crucial threshold: the city and surrounding county, with a population of 80,000, essentially use no oil, natural gas or coal to heat homes and businesses, even during the long frigid winters. It is a complete reversal from 20 years ago, when all of their heat came from fossil fuels.
But this area in southern Sweden, best known as the home of Absolut vodka, has not generally substituted solar panels or wind turbines for the traditional fuels it has forsaken. Instead, as befits a region that is an epicenter of farming and food processing, it generates energy from a motley assortment of ingredients like potato peels, manure, used cooking oil, stale cookies and pig intestines.
A hulking 10-year-old plant on the outskirts of Kristianstad uses a biological process to transform the detritus into biogas, a form of methane. That gas is burned to create heat and electricity, or is refined as a fuel for cars.
Once the city fathers got into the habit of harnessing power locally, they saw fuel everywhere: Kristianstad also burns gas emanating from an old landfill and sewage ponds, as well as wood waste from flooring factories and tree prunings.
Over the last five years, many European countries have increased their reliance on renewable energy, from wind farms to hydroelectric dams, because fossil fuels are expensive on the Continent and their overuse is, effectively, taxed by the European Union’s emissions trading system.
But for many agricultural regions, a crucial component of the renewable energy mix has become gas extracted from biomass like farm and food waste. In Germany alone, about 5,000 biogas systems generate power, in many cases on individual farms.
Kristianstad has gone further, harnessing biogas for an across-the-board regional energy makeover that has halved its fossil fuel use and reduced the city’s carbon dioxide emissions by one-quarter in the last decade.
“It’s a much more secure energy supply — we didn’t want to buy oil anymore from the Middle East or Norway,” said Lennart Erfors, the engineer who is overseeing the transition in this colorful city of 18th-century row houses. “And it has created jobs in the energy sector.”
In the United States, biogas systems are rare. There are now 151 biomass digesters in the country, most of them small and using only manure, according to the Environmental Protection Agency. The E.P.A. estimated that installing such plants would be feasible at about 8,000 farms.
So far in the United States, such projects have been limited by high initial costs, scant government financing and the lack of a business model. There is no supply network for moving manure to a centralized plant and no outlet to sell the biogas generated.
Still, a number of states and companies are considering new investment.
Last month, two California utilities, Southern California Gas and San Diego Gas & Electric, filed for permission with the state’s Public Utilities Commission to build plants in California to turn organic waste from farms and gas from water treatment plants into biogas that would feed into the state’s natural-gas pipelines after purification.
Using biogas would help the utilities meet requirements in California and many other states to generate a portion of their power using renewable energy within the coming decade.
Both natural gas and biogas create emissions when burned, but far less than coal and oil do. And unlike natural gas, which is pumped from deep underground, biogas counts as a renewable energy source: it is made from biological waste that in many cases would otherwise decompose in farm fields or landfills and yield no benefit at all, releasing heat-trapping methane into the atmosphere and contributing to global warming.
This fall, emissaries from Wisconsin’s Bioenergy Initiative toured German biogas programs to help formulate a plan to develop the industry. “Biogas is Wisconsin’s opportunity fuel,” said Gary Radloff, the initiative’s Midwest policy director.
Like Kristianstad, California and Wisconsin produce a bounty of waste from food processing and dairy farms but an inadequate supply of fossil fuel to meet their needs. Another plus is that biogas plants can devour vast quantities of manure that would otherwise pollute the air and could affect water supplies.
In Kristianstad, old fossil fuel technologies coexist awkwardly alongside their biomass replacements. The type of tanker truck that used to deliver heating oil now delivers wood pellets, the major heating fuel in the city’s more remote areas. Across from a bustling Statoil gas station is a modest new commercial biogas pumping station owned by the renewables company Eon Energy.
The start-up costs, covered by the city and through Swedish government grants, have been considerable: the centralized biomass heating system cost $144 million, including constructing a new incineration plant, laying networks of pipes, replacing furnaces and installing generators.
But officials say the payback has already been significant: Kristianstad now spends about $3.2 million each year to heat its municipal buildings rather than the $7 million it would spend if it still relied on oil and electricity. It fuels its municipal cars, buses and trucks with biogas fuel, avoiding the need to purchase nearly half a million gallons of diesel or gas each year.
The operations at the biogas and heating plants bring in cash, because farms and factories pay fees to dispose of their waste and the plants sell the heat, electricity and car fuel they generate.
Kristianstad’s energy makeover is rooted in oil price shocks of the 1980s, when the city could barely afford to heat its schools and hospitals. To save on fuel consumption, the city began laying heating pipes to form an underground heating grid — so-called district heating.
Such systems use one or more central furnaces to heat water or produce steam that is fed into the network. It is far more efficient to pump heat into a system that can warm an entire city than to heat buildings individually with boilers.
District heating systems can generate heat from any fuel source, and like New York City’s, Kristianstad’s initially relied on fossil fuel. But after Sweden became the first country to impose a tax on carbon dioxide emissions from fossil fuels, in 1991, Kristianstad started looking for substitutes.
By 1993, it was taking in and burning local wood wastes, and in 1999, it began relying on heat generated from the new biogas plant. Some buildings that are too remote to be connected to the district heating system have been fitted with individual furnaces that use tiny pellets that are also made from wood waste.
Burning wood in this form is more efficient and produces less carbon dioxide than burning logs does; such heating has given birth to a booming pellet industry in northern Europe. Government subsidies underwrite purchases of pellet furnaces by homeowners and businesses; pellet-fueled heat costs half as much as oil, said Mr. Erfors, the engineer.
Having dispensed with fossil fuels for heating, Kristianstad is moving on to other challenges. City planners hope that by 2020 total local emissions will be 40 percent lower than they were in 1990, and that running the city will require no fossil fuel and produce no emissions at all.
Transportation now accounts for 60 percent of fossil fuel use, so city planners want drivers to use cars that run on local biogas, which municipal vehicles already do. That will require increasing production of the fuel.
Kristianstad is looking into building satellite biogas plants for outlying areas and expanding its network of underground biogas pipes to allow the construction of more filling stations. At the moment, this is something of a chicken-and-egg problem: even though biogas fuel costs about 20 percent less than gasoline, consumers are reluctant to spend $32,000 (about $4,000 more than for a conventional car) on a biogas or dual-fuel car until they are certain that the network will keep growing.
“A tank is enough to get you around the region for the day, but do you have to plan ahead,” Martin Risberg, a county engineer, said as he filled a biogas Volvo.
Before You Lift a Weight, Get Some Advice
By JANE E. BRODY, The New York Times, December 13, 2010
It seems unfair when people get hurt while trying to do something good for their bodies. But that is exactly what happened to nearly a million Americans from 1990 to 2007 when they sought to improve their strength and well-being through weight training — exercises done with free weights or on gym equipment called resistance machines.
To be sure, these injuries are less common than, say, those linked to running, cycling or competitive sports. But a national study, published online in March by The American Journal of Sports Medicine, revealed that these mishaps are on the rise and that they spare no body part, gender or age group.
The study covered 25,335 people aged 6 to 100 who were taken to emergency rooms with weight-training injuries. The research team, from the Nationwide Children’s Hospital in Columbus, Ohio, said that worked out to nearly one million such injuries throughout the country, an increase of 48 percent from the beginning of the 18-year study period to the end.
This year Jessica Cleary, a 40-year-old mother from Chicago, joined the growing number of injured weight trainers. Ms. Cleary said in an interview that she had been working out with free weights and on resistance machines about five times a week for several years. She believed she was well trained, having been guided by a personal trainer for eight months. But on a fateful day last May she slid off a leg-strengthening machine head first, and her neck landed hard on a metal part of the equipment.
Unable to talk and having trouble breathing, she was taken to an emergency room, where tests showed she had fractured her larynx. A challenging operation and three months of recovery later, she said she felt lucky to have ended up with “only a paralyzed vocal cord” and a permanently raspy voice.
“At another gym on a similar piece of equipment, a woman broke her neck,” Ms. Cleary told me.
Safety First
Men were injured in more than 80 percent of cases described in the study — hardly surprising since they are the primary users of weight rooms. But the study showed that weight-training injuries were rising faster among women, many of whom have only recently taken up the activity to help with weight control, bone density and overall ability to perform life’s chores.
Yours truly is now among them. Soon after my husband’s death in March, I realized that without his brawn at my disposal, I needed to enhance my ability to wield heavy tools and carry big loads without hurting my back or shoulders. So, guided by a personal trainer and knowing I have little time to spend in a gym, I learned some simple core-strengthening exercises and bought two sets of free weights to use at home.
I decided to research and write this column in part because I hope to avoid an injury that could make matters worse instead of better.
In the study, sprains and strains to the upper and lower trunk were the most common injuries, and in two-thirds of cases, they resulted from people dropping weights on themselves. More than 90 percent of injuries were incurred using free weights, which were responsible for 24 percent of fractures and dislocations.
While people aged 13 to 24 had the greatest number of injuries, the largest increase occurred among those 45 and older, many of them people like me who want to delay or reverse age-related muscle loss and improve the quality of their later years.
An author of the Ohio study, Dawn Comstock, principal investigator at the Children’s Hospital’s Center for Injury Research and Policy, said that “before beginning a weight-training program, it is important that people of all ages consult with a health professional, such as a doctor or athletic trainer, to create a safe training program based on their age and capabilities.” It is critical as well to get proper instruction on how to use weight-lifting equipment and learn the proper technique, Dr. Comstock said.
Ralph Reiff, athletic trainer and director of St. Vincent Sports Performance in Indianapolis, agreed. “The worst thing a person can do is go into a gym, look around to see what other people are doing, and then start doing it,” he said. Before starting out, he said in an interview, ask a qualified professional to “sit down with you to discuss your goals and the activities you currently do, and then design an individualized weight-training program that is safe relative to any problems you may have.”
In seeking guidance, he said, “don’t be afraid to ask about a trainer’s qualifications.
“Is the trainer certified by the American College of Sports Medicine or the National Athletic Trainers’ Association? Your body is too valuable to take advice from someone without a credible education.”
He recommended that those considering weight training should first be evaluated as to their abilities and limitations — “can you do a full squat, raise your arms over your head, rotate your trunk with your feet flat on the floor and knees bent?” This would be followed by personalized dos and don’ts in the weight room.
Too Much of a Good Thing
The most common cause of weight-training injuries, Mr. Reiff said, is trying to do too much — doing too many repetitions, using too much weight or doing the workout too often.
These practices can result in muscle injury and torn tendons and ligaments, as well as inflammation of the tendons and bursae (the cushionlike sacs around the joints) — all debilitating injuries that can discourage someone from returning to the gym. Lifting weights that are too heavy can injure the rotator cuff in the shoulder or strain the back.
Muscles get stronger when they are worked hard, developing microtears that are healed with protein-rich tissue. But when muscles are overstressed, the serious tears that can result are anything but strengthening.
In bench pressing, it is best to use a spotter to make sure the activity is done safely.
A second common cause of injury is poor technique, Mr. Reiff said. Improper alignment while lifting or using resistance machines can place unnatural or uneven stresses on various body parts. You must have respect for the equipment and know how to use it safely in relation to your size and abilities. The machines themselves can sometimes be a hazard, as Ms. Cleary discovered.
After an injury, it is critical to give the body the time and treatment it needs to heal before returning to weight-training. This does not necessarily mean totally abandoning a strengthening workout. If shoulders are injured, for example, legs can still be worked safely, and vice versa.
By MATTHEW L. WALD, The New York Times, December 13, 2010
Men who grew up in the St. Louis area in the early 1960s and died of cancer by middle age had more than twice as much radioactive strontium in their baby teeth as men born in the same area at the same time who are still living, according to a study based on teeth collected years ago by Washington University in St. Louis.
The study, published on Dec. 1 in The International Journal of Health Services, analyzed baby teeth collected during the era when the United States and the Soviet Union were conducting nuclear bomb tests in the atmosphere. The study seeks to help scientists determine the health effects of small radiation doses, and to say how many people died from bomb fallout. There is very little reliable data on the relationship of radiation to cancer at low doses, so scientists instead use extrapolations from higher doses, which introduces large uncertainties into their calculations.
The study implies that deaths from bomb fallout globally run into the “many thousands,” said the authors, Joseph J. Mangano and Dr. Janette D. Sherman, both of the Radiation and Public Health Project, nonprofit research group based in New York.
However, a scientist with long experience in the issue, Kevin D. Crowley, the senior board director of the Nuclear and Radiation Studies Board at the National Research Council, urged caution in interpreting the findings.
“It sounds like the best you could do is say this is an association,” he said. “An association is not necessarily causative.”
R. William Field, an epidemiologist at the University of Iowa, praised the authors for exploring the association between fallout in teeth and cancer, but he that said the sample size was too small and that the study had other limitations. He called for follow-ups.
The study’s authors had previously tried to link strontium in the teeth of children growing up near nuclear power plants to releases from those plants, but those findings have not met with much scientific acceptance. Strontium levels in a person’s body may have more to do with where the person’s food was farmed than with where the person lives. In addition, the Nuclear Regulatory Commission calculated that the doses from radioactive strontium in the environment add only about 0.3 percent to the average American’s background exposure.
But this study tries to link differences in tooth contamination more directly with health outcomes. The study measured the ratio of calcium, a basic building block of teeth and bones, to strontium 90, which is absorbed just as calcium is. The authors said they were using strontium as a proxy for all long-lived fallout components, and they picked boys born in a period when there was a lull in atmospheric testing, so that the boys’ exposure to short-lived radioactive materials, in utero or in the first few months of life, was minimized. They limited their research to boys because men seldom change their names and thus were easier to trace.
The authors found that among 3,000 tooth donors, born in 1959, 1960 or the first half of 1961, 84 had died, 12 of those from cancer. The authors selected two “control” cases, people still living, for each of those who had died. The controls were born in the same county, within 40 days of the person who later died. The study compared incisors with incisors, and molars with molars.
The people who would later die of cancer had an average of 7.0 picocuries of per gram of tooth; the control cases, who have never had cancer, had an average of 3.1 picocuries per gram.
But the picture is not completely clear. Measurements of the teeth of people who later had cancer but survived it did not show strontium levels markedly different from those who had never had cancer, according to the study. One reason may be that those nonfatal cancers were often polyps and melanomas not related to radiation.
Rings in Sky Leave Alternate Visions of Universes
By DENNIS OVERBYE, The New York Times, December 13, 2010
Last month a pair of physicists startled the world by claiming that they had managed to see through the Big Bang and glimpse evidence of previous incarnations of the universe in an analysis of radio signals from the sky.
The evidence, said Roger Penrose of Oxford University and Vahe Gurzadyan of Yerevan State University in Armenia, takes the form of concentric rings caused by the collisions of supermassive black holes in earlier versions of our universe and imprinted, like ripples on a pond, on a haze of microwave radiation widely thought to be left over from the Big Bang that started our own cycle of time about 13.7 billion years ago.
Now, however, two other groups of astronomers looking at the same data have concluded that the rings, though real, are part of the current universe we already know and love.
The cosmic microwave background, as it is known, has been much scrutinized since its discovery in 1965 by radio telescopes, balloons and three satellites — NASA’s Cosmic Background Explorer and Wilkinson Microwave Anisotropy Probe satellites and, most recently, Europe’s Planck satellite — for clues to the origin of the universe. Slight temperature deviations in what is otherwise an exceedingly uniform heat bath are thought to arise from microscopic fluctuations in a force field known as inflation that drove the expansion of the universe when it was but a sliver of a nanosecond old.
The rings seen by Dr. Penrose and Dr. Gurzadyan are thin bands in which the noisy pattern of heat and cold in the early universe, as recorded by the Wilkinson satellite and other experiments, is slightly less splotchy than normal. They posted a copy of their paper on the Internet on Nov. 16, noting that the rings confirmed a prediction of a theory recently proposed by Dr. Penrose, one of the world’s distinguished mathematicians, called Conformal Cyclic Cosmology. It is the subject of a new book by him, “Cycles of Time: An Extraordinary New View of the Universe,” due out in May from Knopf.
Mainstream cosmologists, who have seen a long list of anomalies in the cosmic background come and go, were not impressed. Now their skepticism is supported by two groups of cosmologists, Ingunn Kathrine Wehus and Hans Eriksen of the University of Oslo in Norway and Adam Moss, Douglas Scott and James P. Zibrin, all of the University of British Columbia. In separate papers based on data from the Wilkinson satellite, both groups reported finding such rings, but said the rings were consistent with having arisen by chance in the earliest moments of our own universe. Eternity is not needed to explain them.
Dr. Moss and his colleagues wrote, “Gurzadyan and Penrose have not found evidence for pre-Big Bang phenomena, but have simply rediscovered that the CMB contains structure.”
David Spergel, a Princeton University astrophysicist and one of the members of the Wilkinson satellite team, said in a e-mail message: “While it would have been exciting to see circles from the pre-Big Bang universe, I view this as science at its best. Exciting claims are made and they draw the attention of cosmologists throughout the world. Because the WMAP data is publicly available, groups throughout the world were able to check the claim. A universe with dark matter, dark energy and inflation is bizarre enough — we don’t, however, get to detect circles from alternative universes.”
But visions of alternative universes keep coming. On Thursday, an international group led by Stephen M. Feeney of University College, London, reported that they had found tentative evidence of blobs in the microwave data that could be bruises from collisions with other universes that bubbled off from our own during the inflation epoch. The evidence, they acknowledged, was too weak to get excited about yet, but could be improved by the Planck satellite, now scanning the sky and expected to report its results in 2012.
“If this evidence is corroborated by upcoming data from the Planck satellite, we will be able to gain insight into the possible existence of the multiverse,” the authors wrote.
Dr. Spergel and Max Tegmark, a cosmologist at M.I.T., both said the group seemed to have done a careful job of analysis. Dr. Tegmark said, “This is going on the list of things people will be majorly looking for in the Planck data.”
This article has been revised to reflect the following correction:
Correction: December 14, 2010
In an earlier version of this article, the picture caption may have left the misleading impression that concentric circular patterns in microwave radiation are clearly visible in satellite data. The image was modified by researchers to highlight what they see as evidence of black hole collisions in earlier versions of our universe.
Anthropology Group Tries to Soothe Tempers After Dropping the Word ‘Science’
By NICHOLAS WADE, The New York Times, December 13, 2010
The battle of the anthropologists — those who hew closely to scientific tradition versus those who take a more humanistic approach — flared again Monday, as the organization that represents both sides tried to patch things up.
The American Anthropological Association had caused a stir by dropping the word “science” from its long-range plan, angering the evidence-based anthropologists who worry about their field’s growing too soft. All three mentions of the word “science” were excised, and two were replaced by the phrase “the public understanding of humankind.”
On Monday, the association issued a statement of clarification, saying it recognizes “the crucial place of the scientific method in much anthropological research.”
Damon Dozier, the association’s director of public affairs, said: “We’ve heard loud and clear from our members that they have concerns about the long-range plan. We’ll look at the words again.”
The association is an umbrella group that includes several disciplines ranging from physical anthropology — like the study of fossilized human skulls — to more interpretive subjects, like research on race and sex. There has been a longstanding cultural gap within the association between the evidence-based researchers, who include some social anthropologists, and those more interested in advocating for the rights of women or native peoples. The new long-range plan, approved last month, inflamed these differences.
In Monday’s statement, the association defined anthropology as “a holistic and expansive discipline that covers the full breadth of human history and culture.” Anthropology draws on the methods of both the humanities and the sciences, it added.
Mr. Dozier said, “We mean holistic in terms of the diversity of the discipline.”
Peter N. Peregrine, president of the Society for Anthropological Sciences, an affiliate of the association, said Monday that he had heard “outrage and tremendous concern” from his members about dropping references to science, some of them asking how they could justify their department’s existence if their national organization did not regard anthropology as a science.
But Mr. Peregrine expressed hope regarding Monday’s statement, interpreting “holistic” to mean that science is included in the anthropological understanding of human beings.
The differences between the humanistic and scientific approaches may, however, be too large to be bridged. “I really don’t see how or why anthropology should entail humanities,” said Frank Marlowe, president-elect of the Evolutionary Anthropology Society, another association affiliate, given that the social sciences are empirical, while the humanities are analytic, critical or speculative.
“We evolutionary anthropologists are outnumbered by the new cultural or social anthropologists, many but not all of whom are postmodern, which seems to translate into antiscience,” Dr. Marlowe said.
Musk Oxen Live to Tell a Survivors’ Tale
By NATALIE ANGIER, The New York Times, December 13, 2010
Among the various large, charismatic and visibly winterized mammals that one might choose as a mascot for life in the Arctic belt, polar bears are, let’s face it, too hackneyed, reindeer too Rudolph, caribou too Sarah Palin’s target practice, and woolly mammoths too extinct.
There’s a better choice, though few may have heard of it. According to Arctic biologists, the quintessential example of megafaunal fortitude in the face of really bad weather is the musk ox, or Ovibos moschatus, a blocky, short-legged, highly social ungulate with distinctively curved horns and long hair that looks like shag carpeting circa 1975.
Ovibos’s common name is only partly justified. The males do emit a musky cologne during mating season, but the animal is not an ox. Nor, despite its back-of-the-nickel silhouette, is it a type of buffalo either. Its closest living relations are thought to be goats and sheep, but taxonomically and metaphorically, the musk ox is in an icy cubicle of its own. Once abundant throughout the northern latitudes worldwide, today they are found only in Arctic North America, Greenland and pockets of Siberia and Scandinavia. The musk ox is a holdover from the Pleistocene, the age of the giant mammals memorialized in natural history murals everywhere — the mammoths and mastodons, the saber-toothed cats, the giant ground sloths, the 400-pound beavers. Yet while a vast majority of the frost-fitted bigfoots disappeared at the end of the last ice age, 10,000 years ago, Ovibos hung on, as stubbornly as the ox it is not.
Scientists are now seeking to understand how, exactly, the animal has managed to persist through repeated climate shifts and habitat upheavals. Researchers see in the musk ox’s story clues to help guide efforts to conserve other large land mammals now at risk of extinction. They also hope to raise the profile of a species they consider magnificent, at once stalwart and supple, a page of living prehistory whose social and behavioral complexities they have just begun to decode.
“There’s evidence that they have an elephantlike social structure, and even some form of culture,” said Joel Berger, a researcher with the Wildlife Conservation Society and a professor at the University of Montana. So why is everybody flying to Africa to see elephants when we’ve got this marvelous species living in our own backyard?
In a presentation last week at the Bronx Zoo, where the wildlife society is based, Dr. Berger described preliminary results from field studies of the musk ox that he has performed with Layne Adams of the U.S. Geological Survey and other collaborators. He talked about the challenges of catching animals to weigh and measure them, check their teeth, take their blood and furnish them with G.P.S. collars. One group of musk ox in Cape Krusenstern National Monument in Alaska had such bad, broken teeth you’d think they were subsisting on a diet of Pepsi and Snickers bars, said Dr. Berger, and the researchers worried that the population was unhealthy and on its way out.
Yet after suffering several seasons of declining numbers, the brown-toothers rebounded this year to match in fecundity and offspring survival a group living in the Bering Land Bridge National Preserve that had exemplary teeth. The cause of their rotten dentition remains a mystery, but the Krusenstern clan clearly was not biting the dust.
For all their storied past as co-prancers with mastodons, musk oxen are not huge animals. Adult males stand about four feet high and weigh around 600 to 700 pounds, less than half the weight of the average draft horse. Yet they look hulky as a result of their spectacular double-layered fur coat. The long, shaggy outer layer they keep year round, not only to help shield them against the brutal cold of an Arctic winter, when temperatures can plunge 40 degrees or more below zero, but also to deter the insect pests of an Arctic summer.
“You’ll see caribou in summertime trotting across the countryside trying to get away from all the mosquitoes and biting flies,” said Jim Lawler, a biologist with the National Park Service’s Arctic Network in Fairbanks. “But the musk ox just stand there with clouds of mosquitoes hovering above them. It’s hard to penetrate that fur.” For added insulation, musk oxen grow a second fur layer each winter, an undercoat called qiviut that is said to be many times warmer than wool and softer than cashmere — and how obliging of the animals to shed that qiviut in spring for use in scarves.
With their stubby legs, musk oxen are not migratory like caribou or great dashers like reindeer. Their basic approach to winter management is: Don’t just do something — stand there. “You’ll see them in a big storm, drifted over, covered with snow,” said Dr. Lawler. “They’re almost part of the scenery.” They lapse into a state of what might be called hibernation al fresco, as their oxygen consumption and carbon dioxide production drop and their metabolic rate slows by about a third. “They’re basically shutting down some of their machinery so they can survive on less food,” said Dr. Lawler, who has studied musk ox energetics.
Whatever their occasional resemblance to the scenery, musk oxen are by no means as dumb as a post. “They live in loosely knit family-bonded societies,” said Dr. Berger, and they keep track of who’s who. The group is, after all, essential to their survival. When confronted with predators like wolves, a herd of musk oxen will famously circle the wagons, the adults forming a wall of horns facing outward, the vulnerable young safely shielded behind them. They also seem to have a keen memory for where the best foraging grounds may be found in the spring, the optimal mix of grasses and willow twigs to maximize the performance of the microbes at work in their ruminant gut. Musk oxen turn out to be very efficient at extracting calories to put on the fat they need to survive the long winter fast.
Historical records and genetic evidence alike suggest that the musk ox is a Rasputin, “the comeback kid of the Quaternary,” said Ross MacPhee, curator of vertebrate zoology at the American Museum of Natural History. “They undergo periods where they really bolster their numbers for a few years, then they go down to an almost complete collapse, then later they come back like gangbusters.”
As a result of passing through repeated population bottlenecks, in which only a handful of individuals survived to spawn subsequent generations, today’s 100,000 musk oxen are thought to be notably homogenous, lacking in the sort of genetic diversity once thought critical to a species’ long-term prospects. “It would be hard to argue that musk ox are on their way out the door,” said Dr. MacPhee. “They are not weak sisters.”
Just ask that saber-toothed cat fossilized under the floor.
Poisoned Debate Encircles a Microbe Study’s Result
By DENNIS OVERBYE, , The New York Times, December 13, 2010
The announcement that NASA experimenters had found a bacterium that seems to be able to subsist on arsenic in place of phosphorus — an element until now deemed essential for life — set off a cascading storm of criticism on the Internet, first about alleged errors and sloppiness in the paper published in Science by Felisa Wolfe-Simon and her colleagues, and then about their and NASA’s refusal to address the criticisms.
The result has been a stormy brew of debate about the role of peer review, bloggers and the reliability of NASA, at least as it pertains to microbiological issues, almost as toxic as the salty and arsenic waters of Mono Lake in California, from which Dr. Wolfe-Simon of the U.S. Geological Survey scooped up some bacteria last year.
Seeking evidence that life could follow a different biochemical path than what is normally assumed, Dr. Wolfe-Simon grew them in an arsenic-rich and phosphorus-free environment, reporting in the paper and a NASA news conference on Dec. 2 that the bacterium, strain GFAJ-1 of the Halomonadaceae family of Gammaproteobacteria, had substituted arsenic for phosphorus in many important molecules in its body, including DNA.
But the ink had hardly dried on headlines around the world when microbiologists, who have been suspicious of NASA ever since the agency announced that it had found fossils of microbes in a meteorite from Mars in 1996, began shooting back, saying the experimenters had failed to provide any solid evidence that arsenic had actually been incorporated into the bacterium’s DNA.
In a scathing commentary on her blog RRResearch, Rosie Redfield, a microbiologist at the University of British Columbia, in Vancouver, ran through a long list of what she said were errors and omissions in the paper, which she summarized in the end as “lots of flim-flam, but very little reliable information.”
Among other mistakes, she and others say, the experimenters failed to wash the bug’s DNA before testing it for arsenic, thus leaving the possibility that the arsenic detected there was just stuck to the outside of the giant molecule, like mud on the bottom of a shoe, a process she described as “Microbiology 101.” Over the course of a week her blog, which normally has a few hundred visitors a day, recorded almost 90,000 hits before the furor died down. She has also sent a letter to Science.
Things got nastier when NASA and Dr. Wolfe-Simon refused to respond to such criticisms, which quickly leapt from Dr. Redfield and others’ blogs to Wired and Slate and The Observatory, a blog covering the science press for the Columbia Journalism Review. According to CBC News, Dwayne Brown, a NASA spokesman, said that the agency wouldn’t debate science with bloggers and would stick to peer-reviewed literature. The online tech magazine Gizmodo ran a highly doctored picture of Dr. Redfield and Dr. Wolfe-Simon staring lightning bolts at each other.
In a statement on her own Web site, Dr. Wolfe-Simon noted that the paper had been carefully peer-reviewed and said, “We’ve been concerned that some conclusions have been drawn based on claims not made in our paper,” but did not elaborate on what those mistaken claims were.
In the interest of stimulating healthy debate, she said, Science was making the paper available free of charge (although registration is required) for a couple of weeks. The experimenters are compiling a list of answers for frequently asked questions, which can be sent to gfajquestions@gmail.com and will eventually be posted online.
Dr. Redfield said Mr. Brown’s reaction was silly. “We are the peers,” she said.
Conversation and arguing have always been an important part of how science has been done, she said. Once upon a time it was by mail, and was private and slow. “Now,” she said, “the conversation is carried out in public in ways everyone can see.”
She added, “This kind of intellectual analysis and give and take is a big chunk of the fun of doing science.”
Nevertheless, she said she sympathized with Dr. Wolfe-Simon’s position as a woman in science advocating a controversial view, and she agreed with her decision to keep a low peer-reviewed profile. More arguing, as a blogger who goes by the name of Isis pointed out in a post titled “Don’t Like Arsenic Bacteria? Put Your Experiment Where Your Mouth Is!,” will not solve the problem.
Only more data, which will probably be forthcoming, will tell whether the GFAJ-1 bug is weird life that has found a new way to live, or just tough and able to survive in arsenic. If the original paper was right, that would be “great,” said Dr. Redfield. But the opposite could also be presented as a demonstration that life is such a powerful force.
“NASA can spin it either way,” she said.
In a Single-Cell Predator, Clues to the Animal Kingdom’s Birth
By SEAN B. CARROLL, The New York Times, December 13, 2010
The Environmental Protection Agency is worried about a lot of things in our water — polychlorinated biphenyls, dibromochloropropane, Cryptosporidium parvum — to name just a few of the dozens of chemicals or organisms they monitor. However, in nearly every creek and lake, and throughout the oceans, there is one important group of multisyllabic microbes that the E.P.A. does not track, and until recently, most biologists heard and knew very little about — the choanoflagellates.
Before you spit out that glass of water or dunk your swimsuit in Clorox, relax. These tiny organisms are harmless. They are important for other reasons. They are part of the so-called nanoplankton and play critical roles in the ocean food chain. Choanoflagellates are voracious single-cell predators.
The beating of their long flagellum both propels them through the water and creates a current that helps them to collect bacteria and food particles in the collar of 30 to 40 tentaclelike filaments at one end of the cell.
There can be thousands to millions of choanoflagellates in a gallon of sea water, which may filter 10 to 25 percent of coastal surface water per day. Choanoflagellates in turn serve as food for planktonic animals like crustacean larvae, which are consumed by larger animals, and so on up the food chain.
Theirs is a humble existence compared with the larger, more charismatic residents of the oceans like lobsters, fish, squids and whales.
But recent studies suggest that these obscure organisms are among the closest living single-celled relatives of animals. In other words, choanoflagellates are cousins to all animals in the same way that chimpanzees are cousins to humans. Just as the study of great apes has been vital to understanding human evolution, biologists are now scrutinizing choanoflagellates for clues about one of the great transitions in history — the origin of the animal kingdom.
For most of the first 2.5 billion years of life on Earth, most species were microscopic, rarely exceeding one millimeter in size, and unicellular. Many different kinds of larger life forms, including fungi, animals and plants, subsequently evolved independently from separate single-celled ancestors.
The evolution of multicellularity was a critical step in the origin of each of these groups because it opened the way to the emergence of much more complex organisms in which different cells could take on different tasks. And the emergence of larger organisms drove profound changes in ecology that changed the face of the planet.
Scientists are eager to understand how transitions from a unicellular to multicellular lifestyle were accomplished. Reconstructing events that happened more than 600 million years ago, in the case of animals, is a great challenge. Ideally, one would have specimens from just before and immediately after the event. But the unicellular ancestor of animals and those first animals are long extinct. So information has to be gleaned from living sources.
This is where comparisons between choanoflagellates and animals come into play. The close kinship between choanoflagellates and animals means that there once lived a single-celled ancestor that gave rise to two lines of evolution — one leading to the living choanoflagellates and the other to animals. Choanoflagellates can tell us a lot about that ancestor because any characteristics that they share with animals must have been present in that ancestor and then inherited by both groups. By similar logic, whatever animals have but choanoflagellates lack probably arose during animal evolution.
There are striking physical resemblances between choanoflagellates and certain animal cells, specifically the feeding cells of sponges, called choanocytes. Sponge choanocytes also have a flagellum and possess a collar of filaments for trapping food. Similar collars have been seen on several kinds of animals cells. These similarities indicate that the unicellular ancestor of animals probably had a flagellum and a collar, and may have been much like a choanoflagellate.
But even more surprising and informative resemblances between choanoflagellates and animals have been revealed at the level of DNA. Recently, the genome sequence of one choanoflagellate species was analyzed by a team led by Nicole King and Daniel Rokhsar at the University of California, Berkeley. They identified many genetic features that were shared exclusively between choanoflagellates and animals. These included 78 pieces of proteins, many of which in animals are involved in making cells adhere to one another.
The presence of so many cell adhesion molecules in choanoflagellates was very surprising. The scientists are trying to figure out what all of those molecules are doing in a unicellular creature. One possibility is that the molecules are used in capturing prey.
Whatever the explanation, the presence of those genes in a unicellular organism indicates that much of the machinery for making multicellular animals was in place long before the origin of animals. It may be that rather than evolving new genes, animal ancestors simply used what they had to become multicellular. There may be selective advantages to forming colonies, like avoiding being eaten by other small predators. And in fact, some choanoflagellates do form multicellular colonies at stages of their life cycle.
Dr. King and her colleagues Stephen Fairclough and Mark Dayel investigated one such species to determine whether colony formation occurred by dividing cells staying together, the way animal embryos form, or by individual cells aggregating together, as some protists like slime molds do.
The scientists found that colonies formed exclusively by dividing cells staying together. They suggested that the ancient common ancestor of choanoflagellates and animals was capable of forming simple colonies and that this property may well have been a first step on the road to animal evolution.
The world is full of microbes, and we spend a lot of worry and effort trying to keep them off and out of our bodies. It is humbling to ponder that still swimming within that microscopic soup are our distant cousins.
This article has been revised to reflect the following correction:
Correction: December 14, 2010
An earlier version of this article misspelled the surname of a researcher at the University of California, Berkeley. He is Mark Dayel, not Doyel. And a credit for a picture of feeding cells of sponges misspelled the photographer's surname. He is Scott Nichols, not Nichol.
Birds Do It ... We Do It ... and No One Knows Why
By NICHOLAS BAKALAR, The New York Times, December 13, 2010
Everyone yawns, but no one knows why. We start when we are in the womb, and we do it through old age. Most vertebrate species, even birds and fishes, yawn too, or at least do something that looks very much like it. But its physiological mechanisms, its purpose and what survival value it might have remain a mystery.
There is no shortage of theories — a recent article in the journal Neuroscience & Biobehavioral Reviews outlines many — but a dearth of experimental proof that any of them is correct.
“The lack of experimental evidence is sometimes accompanied by passionate discussion,” said Dr. Adrian G. Guggisberg, the lead author.
Hippocrates proposed in the fourth century B.C. that yawning got rid of “bad air,” and increased “good air” in the brain. The widely held modern view of this theory is that yawning helps increase blood oxygen levels and decrease carbon dioxide.
If this were true, Dr. Guggisberg writes, then people would yawn more when they exercise. And people with lung or heart disease, who often suffer from a lack of oxygen, yawn no more than anyone else.
Researchers have exposed healthy subjects to gas mixtures with high levels of carbon dioxide and found that it does not lead to increased yawning. In fact, there is no study that shows that oxygen levels in the brain are changed one way or the other by yawning.
In other words, observation and experiment suggest that the best way to increase blood oxygen levels is not yawning, but rapid breathing.
There is no question that yawning occurs most frequently before and after sleep, and the subjective feeling of drowsiness accompanies increased yawning. So maybe yawning helps keep us awake.
Researchers tested this hypothesis by inducing yawning in human subjects and then observing brain activity with encephalography as they yawned. The EEG produced no evidence that yawning increased vigilance in the brain or central nervous system.
Some researchers have suggested the opposite — that yawning lowers arousal and helps us go to sleep. But even though yawning and drowsiness occur together, no experiment has shown a causal connection between the two.
Could the purpose of yawning be regulation of body heat? Researchers have shown that contagious yawns (induced with yawning videos) can be decreased when a cold pack is placed on the forehead, and increased with a warm pack. But the experiment, Dr. Guggisberg says, did not control for other factors — a nice warm pack is likely to increase drowsiness, and a cold pack to increase wakefulness, making it impossible to determine the effect of temperature.
While Dr. Guggisberg finds the evidence for the thermal regulation theory inconclusive, Andrew C. Gallup, a postdoctoral fellow at Princeton, disagrees.
“In rat experiments, yawning is preceded by rapid increases in brain temperature and following the yawning a return to lower temperatures,” he said. “That suggests an association with a thermoregulatory function, although it can’t be interpreted as causal.”
Dr. Gallup outlines his position in an article accepted for publication in Neuroscience & Biobehavioral Reviews, the same journal in which Dr. Guggisberg’s review appears.
Another theory is that yawning helps equalize pressure in the middle ear with outside air pressure. But that function can be fulfilled by other techniques — chewing or swallowing — so there is no reason to believe that yawning has an essential evolutionary advantage. And there is no evidence that yawning increases with air pressure changes.
So what purpose does yawning serve?
Children under 5 are not subject to contagious yawning, but adult humans, chimpanzees, monkeys and dogs — animals with advanced social skills — are. Apparently an understanding of the mental states of others is required before yawning becomes catching.
That idea is supported by M.R.I. observation in humans: watching others yawn activates brain regions related to imitation, empathy and social behavior.
For Dr. Guggisberg, this social interpretation is the only one that appears to account for all the aspects of the phenomenon. But Dr. Gallup points out that solitary species yawn, too, and that chimpanzees and humans yawn when they are alone.
Dr. Gallup conceded that yawning might have some social function in some species. But he said, “Any social function that it has would be a derived feature, and not a more primitive underlying feature of the behavior.”
Dr. Guggisberg, a researcher at the University of Geneva, offered a conclusion that few experts will find objectionable. “Yawning,” he said “is a very rich and complex phenomenon.”
Rare Albatross Expands Its Breeding Grounds
By SINDYA N. BHANOO, The New York Times, December 13, 2010
Two pairs of the short-tailed albatross, thought to remain only on two Japanese islands, have been found nesting on Kure Atoll and on Midway Atoll, American wildlife refuges in the Hawaiian Islands.
Until now, the last remaining breeding colonies of the birds were thought to have been on the Japanese islands. The total adult population of the species is only about 3,000.
The new finding brings hope that the bird might propagate beyond Japan, said Jessica Hardesty Norris, director of the Seabird Program at the American Bird Conservancy, a conservation organization.
“Where they breed in Japan is a pretty decent habitat, but there’s a really active and nasty volcano,” she said. “It could wipe out the species, so we are excited about the prospect of another viable colony.”
The short-tailed albatross is a striking bird, with a bright pink bill, a white body and a golden-colored crown and nape.
Although the bird once thrived in the islands of the Pacific Ocean, the appeal of its feathers for hats and other decorative purposes led to a drop in population in the late 19th century.
Some breeding grounds in Torishima, Japan, were damaged in a volcanic eruption in 1939, and the number of nesting pairs fell to about 10.
The birds that were recently found include one male-female pair, with a fertilized egg, and one female-female pair with two eggs. It is still unclear whether the eggs of the same-sex pair are fertilized.
Using Waste, Swedish City Cuts Its Fossil Fuel Use
By ELISABETH ROSENTHAL, , The New York Times, December 13, 2010
KRISTIANSTAD, Sweden — When this city vowed a decade ago to wean itself from fossil fuels, it was a lofty aspiration, like zero deaths from traffic accidents or the elimination of childhood obesity.
But Kristianstad has already crossed a crucial threshold: the city and surrounding county, with a population of 80,000, essentially use no oil, natural gas or coal to heat homes and businesses, even during the long frigid winters. It is a complete reversal from 20 years ago, when all of their heat came from fossil fuels.
But this area in southern Sweden, best known as the home of Absolut vodka, has not generally substituted solar panels or wind turbines for the traditional fuels it has forsaken. Instead, as befits a region that is an epicenter of farming and food processing, it generates energy from a motley assortment of ingredients like potato peels, manure, used cooking oil, stale cookies and pig intestines.
A hulking 10-year-old plant on the outskirts of Kristianstad uses a biological process to transform the detritus into biogas, a form of methane. That gas is burned to create heat and electricity, or is refined as a fuel for cars.
Once the city fathers got into the habit of harnessing power locally, they saw fuel everywhere: Kristianstad also burns gas emanating from an old landfill and sewage ponds, as well as wood waste from flooring factories and tree prunings.
Over the last five years, many European countries have increased their reliance on renewable energy, from wind farms to hydroelectric dams, because fossil fuels are expensive on the Continent and their overuse is, effectively, taxed by the European Union’s emissions trading system.
But for many agricultural regions, a crucial component of the renewable energy mix has become gas extracted from biomass like farm and food waste. In Germany alone, about 5,000 biogas systems generate power, in many cases on individual farms.
Kristianstad has gone further, harnessing biogas for an across-the-board regional energy makeover that has halved its fossil fuel use and reduced the city’s carbon dioxide emissions by one-quarter in the last decade.
“It’s a much more secure energy supply — we didn’t want to buy oil anymore from the Middle East or Norway,” said Lennart Erfors, the engineer who is overseeing the transition in this colorful city of 18th-century row houses. “And it has created jobs in the energy sector.”
In the United States, biogas systems are rare. There are now 151 biomass digesters in the country, most of them small and using only manure, according to the Environmental Protection Agency. The E.P.A. estimated that installing such plants would be feasible at about 8,000 farms.
So far in the United States, such projects have been limited by high initial costs, scant government financing and the lack of a business model. There is no supply network for moving manure to a centralized plant and no outlet to sell the biogas generated.
Still, a number of states and companies are considering new investment.
Last month, two California utilities, Southern California Gas and San Diego Gas & Electric, filed for permission with the state’s Public Utilities Commission to build plants in California to turn organic waste from farms and gas from water treatment plants into biogas that would feed into the state’s natural-gas pipelines after purification.
Using biogas would help the utilities meet requirements in California and many other states to generate a portion of their power using renewable energy within the coming decade.
Both natural gas and biogas create emissions when burned, but far less than coal and oil do. And unlike natural gas, which is pumped from deep underground, biogas counts as a renewable energy source: it is made from biological waste that in many cases would otherwise decompose in farm fields or landfills and yield no benefit at all, releasing heat-trapping methane into the atmosphere and contributing to global warming.
This fall, emissaries from Wisconsin’s Bioenergy Initiative toured German biogas programs to help formulate a plan to develop the industry. “Biogas is Wisconsin’s opportunity fuel,” said Gary Radloff, the initiative’s Midwest policy director.
Like Kristianstad, California and Wisconsin produce a bounty of waste from food processing and dairy farms but an inadequate supply of fossil fuel to meet their needs. Another plus is that biogas plants can devour vast quantities of manure that would otherwise pollute the air and could affect water supplies.
In Kristianstad, old fossil fuel technologies coexist awkwardly alongside their biomass replacements. The type of tanker truck that used to deliver heating oil now delivers wood pellets, the major heating fuel in the city’s more remote areas. Across from a bustling Statoil gas station is a modest new commercial biogas pumping station owned by the renewables company Eon Energy.
The start-up costs, covered by the city and through Swedish government grants, have been considerable: the centralized biomass heating system cost $144 million, including constructing a new incineration plant, laying networks of pipes, replacing furnaces and installing generators.
But officials say the payback has already been significant: Kristianstad now spends about $3.2 million each year to heat its municipal buildings rather than the $7 million it would spend if it still relied on oil and electricity. It fuels its municipal cars, buses and trucks with biogas fuel, avoiding the need to purchase nearly half a million gallons of diesel or gas each year.
The operations at the biogas and heating plants bring in cash, because farms and factories pay fees to dispose of their waste and the plants sell the heat, electricity and car fuel they generate.
Kristianstad’s energy makeover is rooted in oil price shocks of the 1980s, when the city could barely afford to heat its schools and hospitals. To save on fuel consumption, the city began laying heating pipes to form an underground heating grid — so-called district heating.
Such systems use one or more central furnaces to heat water or produce steam that is fed into the network. It is far more efficient to pump heat into a system that can warm an entire city than to heat buildings individually with boilers.
District heating systems can generate heat from any fuel source, and like New York City’s, Kristianstad’s initially relied on fossil fuel. But after Sweden became the first country to impose a tax on carbon dioxide emissions from fossil fuels, in 1991, Kristianstad started looking for substitutes.
By 1993, it was taking in and burning local wood wastes, and in 1999, it began relying on heat generated from the new biogas plant. Some buildings that are too remote to be connected to the district heating system have been fitted with individual furnaces that use tiny pellets that are also made from wood waste.
Burning wood in this form is more efficient and produces less carbon dioxide than burning logs does; such heating has given birth to a booming pellet industry in northern Europe. Government subsidies underwrite purchases of pellet furnaces by homeowners and businesses; pellet-fueled heat costs half as much as oil, said Mr. Erfors, the engineer.
Having dispensed with fossil fuels for heating, Kristianstad is moving on to other challenges. City planners hope that by 2020 total local emissions will be 40 percent lower than they were in 1990, and that running the city will require no fossil fuel and produce no emissions at all.
Transportation now accounts for 60 percent of fossil fuel use, so city planners want drivers to use cars that run on local biogas, which municipal vehicles already do. That will require increasing production of the fuel.
Kristianstad is looking into building satellite biogas plants for outlying areas and expanding its network of underground biogas pipes to allow the construction of more filling stations. At the moment, this is something of a chicken-and-egg problem: even though biogas fuel costs about 20 percent less than gasoline, consumers are reluctant to spend $32,000 (about $4,000 more than for a conventional car) on a biogas or dual-fuel car until they are certain that the network will keep growing.
“A tank is enough to get you around the region for the day, but do you have to plan ahead,” Martin Risberg, a county engineer, said as he filled a biogas Volvo.
Before You Lift a Weight, Get Some Advice
By JANE E. BRODY, The New York Times, December 13, 2010
It seems unfair when people get hurt while trying to do something good for their bodies. But that is exactly what happened to nearly a million Americans from 1990 to 2007 when they sought to improve their strength and well-being through weight training — exercises done with free weights or on gym equipment called resistance machines.
To be sure, these injuries are less common than, say, those linked to running, cycling or competitive sports. But a national study, published online in March by The American Journal of Sports Medicine, revealed that these mishaps are on the rise and that they spare no body part, gender or age group.
The study covered 25,335 people aged 6 to 100 who were taken to emergency rooms with weight-training injuries. The research team, from the Nationwide Children’s Hospital in Columbus, Ohio, said that worked out to nearly one million such injuries throughout the country, an increase of 48 percent from the beginning of the 18-year study period to the end.
This year Jessica Cleary, a 40-year-old mother from Chicago, joined the growing number of injured weight trainers. Ms. Cleary said in an interview that she had been working out with free weights and on resistance machines about five times a week for several years. She believed she was well trained, having been guided by a personal trainer for eight months. But on a fateful day last May she slid off a leg-strengthening machine head first, and her neck landed hard on a metal part of the equipment.
Unable to talk and having trouble breathing, she was taken to an emergency room, where tests showed she had fractured her larynx. A challenging operation and three months of recovery later, she said she felt lucky to have ended up with “only a paralyzed vocal cord” and a permanently raspy voice.
“At another gym on a similar piece of equipment, a woman broke her neck,” Ms. Cleary told me.
Safety First
Men were injured in more than 80 percent of cases described in the study — hardly surprising since they are the primary users of weight rooms. But the study showed that weight-training injuries were rising faster among women, many of whom have only recently taken up the activity to help with weight control, bone density and overall ability to perform life’s chores.
Yours truly is now among them. Soon after my husband’s death in March, I realized that without his brawn at my disposal, I needed to enhance my ability to wield heavy tools and carry big loads without hurting my back or shoulders. So, guided by a personal trainer and knowing I have little time to spend in a gym, I learned some simple core-strengthening exercises and bought two sets of free weights to use at home.
I decided to research and write this column in part because I hope to avoid an injury that could make matters worse instead of better.
In the study, sprains and strains to the upper and lower trunk were the most common injuries, and in two-thirds of cases, they resulted from people dropping weights on themselves. More than 90 percent of injuries were incurred using free weights, which were responsible for 24 percent of fractures and dislocations.
While people aged 13 to 24 had the greatest number of injuries, the largest increase occurred among those 45 and older, many of them people like me who want to delay or reverse age-related muscle loss and improve the quality of their later years.
An author of the Ohio study, Dawn Comstock, principal investigator at the Children’s Hospital’s Center for Injury Research and Policy, said that “before beginning a weight-training program, it is important that people of all ages consult with a health professional, such as a doctor or athletic trainer, to create a safe training program based on their age and capabilities.” It is critical as well to get proper instruction on how to use weight-lifting equipment and learn the proper technique, Dr. Comstock said.
Ralph Reiff, athletic trainer and director of St. Vincent Sports Performance in Indianapolis, agreed. “The worst thing a person can do is go into a gym, look around to see what other people are doing, and then start doing it,” he said. Before starting out, he said in an interview, ask a qualified professional to “sit down with you to discuss your goals and the activities you currently do, and then design an individualized weight-training program that is safe relative to any problems you may have.”
In seeking guidance, he said, “don’t be afraid to ask about a trainer’s qualifications.
“Is the trainer certified by the American College of Sports Medicine or the National Athletic Trainers’ Association? Your body is too valuable to take advice from someone without a credible education.”
He recommended that those considering weight training should first be evaluated as to their abilities and limitations — “can you do a full squat, raise your arms over your head, rotate your trunk with your feet flat on the floor and knees bent?” This would be followed by personalized dos and don’ts in the weight room.
Too Much of a Good Thing
The most common cause of weight-training injuries, Mr. Reiff said, is trying to do too much — doing too many repetitions, using too much weight or doing the workout too often.
These practices can result in muscle injury and torn tendons and ligaments, as well as inflammation of the tendons and bursae (the cushionlike sacs around the joints) — all debilitating injuries that can discourage someone from returning to the gym. Lifting weights that are too heavy can injure the rotator cuff in the shoulder or strain the back.
Muscles get stronger when they are worked hard, developing microtears that are healed with protein-rich tissue. But when muscles are overstressed, the serious tears that can result are anything but strengthening.
In bench pressing, it is best to use a spotter to make sure the activity is done safely.
A second common cause of injury is poor technique, Mr. Reiff said. Improper alignment while lifting or using resistance machines can place unnatural or uneven stresses on various body parts. You must have respect for the equipment and know how to use it safely in relation to your size and abilities. The machines themselves can sometimes be a hazard, as Ms. Cleary discovered.
After an injury, it is critical to give the body the time and treatment it needs to heal before returning to weight-training. This does not necessarily mean totally abandoning a strengthening workout. If shoulders are injured, for example, legs can still be worked safely, and vice versa.
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