"Under NASA policy, it is inappropriate to discuss personnel matters," said Dean Acosta, the deputy assistant administrator for public affairs and Mr. Deutsch's boss.

The resignation came as the National Aeronautics and Space Administration was preparing to review its policies for communicating science to the public. The review was ordered Friday by Michael D. Griffin, the NASA administrator, after a week in which many agency scientists and midlevel public affairs officials described to The New York Times instances in which they said political pressure was applied to limit or flavor discussions of topics uncomfortable to the Bush administration, particularly global warming.

"As we have stated in the past, NASA is in the process of revising our public affairs policies across the agency to ensure our commitment to open and full communications," the statement from Mr. Acosta said.

The statement said the resignation of Mr. Deutsch was "a separate matter."

Mr. Deutsch, 24, was offered a job as a writer and editor in NASA's public affairs office in Washington last year after working on President Bush's re-election campaign and inaugural committee, according to his résumé. No one has disputed those parts of the document.

According to his résumé, Mr. Deutsch received a "Bachelor of Arts in journalism, Class of 2003."

Yesterday, officials at Texas A&M said that was not the case.

"George Carlton Deutsch III did attend Texas A&M University but has not completed the requirements for a degree," said an e-mail message from Rita Presley, assistant to the registrar at the university, responding to a query from The Times.

Repeated calls and e-mail messages to Mr. Deutsch on Tuesday were not answered.

Mr. Deutsch's educational record was first challenged on Monday by Nick Anthis, who graduated from Texas A&M last year with a biochemistry degree and has been writing a Web log on science policy, scientificactivist.blogspot.com.

After Mr. Anthis read about the problems at NASA, he said in an interview: "It seemed like political figures had really overstepped the line. I was just going to write some commentary on this when somebody tipped me off that George Deutsch might not have graduated."

He posted a blog entry asserting this after he checked with the university's association of former students. He reported that the association said Mr. Deutsch received no degree.

A copy of Mr. Deutsch's résumé was provided to The Times by someone working in NASA headquarters who, along with many other NASA employees, said Mr. Deutsch played a small but significant role in an intensifying effort at the agency to exert political control over the flow of information to the public.

Such complaints came to the fore starting in late January, when James E. Hansen, the climate scientist, and several midlevel public affairs officers told The Times that political appointees, including Mr. Deutsch, were pressing to limit Dr. Hansen's speaking and interviews on the threats posed by global warming.

Yesterday, Dr. Hansen said that the questions about Mr. Deutsch's credentials were important, but were a distraction from the broader issue of political control of scientific information.

"He's only a bit player," Dr. Hansen said of Mr. Deutsch. " The problem is much broader and much deeper and it goes across agencies. That's what I'm really concerned about."

"On climate, the public has been misinformed and not informed," he said. "The foundation of a democracy is an informed public, which obviously means an honestly informed public. That's the big issue here."

Proving carbon in Martian meteorites is indigenous - and not contamination from Earth - is crucial to the question of whether life once arose on the Red Planet.

Initial measurements support the idea that the "carbonaceous material" is not contamination, the scientists say.

Details will be presented at the Lunar and Planetary Science Conference in Houston, Texas, next month. The research team includes scientists who brought evidence for microbial life in another Martian meteorite, ALH84001, to the world's attention in 1998.

The Martian meteorites are an extremely rare class of rocks. They are all believed to have been blasted off the surface of the Red Planet by huge impacts; the material would have drifted through space for millions of years before falling to Earth.

Fresh samples

The latest data comes from examination of a piece of the famous Nakhla meteorite which came down in Egypt, in 1911, breaking up into many fragments.

London's Natural History Museum, which holds several intact chunks of the meteorite, agreed to break one open, providing the researchers with fresh samples.

"It gives people a degree of confidence this had never been exposed to the museum environment," said co-author Colin Pillinger of the UK's Open University.

"I think it's too early to say how [the carbonaceous material] got there... the important thing is that people are always arguing with fallen meteorites that this is something that got in there after it fell to Earth.

"I think we can dismiss that. There's no way a solid piece of carbon got inside a meteorite."

Analysis of the interior revealed channels and pores filled with a complex mixture of carbon compounds. Some of this forms a dark, branching - or dendritic - material when seen under the microscope.

"It's really interesting material. We don't exactly know what it means yet, but it's all over the thin sections of the Nakhla material," said co-author Kathie Thomas Keprta, of Lockheed Martin Corporation in Houston, Texas.

Indigenous component

Previous studies of the forms - or isotopes - of carbon in the Nakhla meteorite found a component of which more than 75% is lacking any carbon-14.

Since all terrestrial life forms contain some carbon-14, this component was thought to be either indigenous carbon from Mars or ancient meteoritic carbon.

Professor Pillinger and colleagues are carrying out direct isotopic analysis of the carbonaceous material, but he admits terrestrial contamination is occurring when thin slices of the meteorite are made for analysis.

However, the ratio of carbon to nitrogen in the epoxy used to prepare the thin sections is very different from that of the carbonaceous material in the meteorite's veins.

If it is indigenous to Mars, the authors say the "carbonaceous material" came either from another space rock that smashed into Mars hundreds of thousands of years ago, or a relic of microbial activity.

A resemblance between the material in the meteorite and features of microbial activity in volcanic glass from our planet's ocean floor further support the idea they are biological in origin, says the paper.

If this were the case, the remains of these organisms and their slimy coatings might provide the the carbon-rich material found in Nakhla, the researchers argue.

Peter Buseck, regent's professor of geological sciences at Arizona State University told the BBC News website that he found no strong evidence of a biological origin for the carbon in the meteorite.

He added that it was difficult to determine the origin of carbon in rocks based on microscopy.

The 37th Lunar and Planetary Science Conference runs from 13-17 March in Houston, Texas.

A study by scientists in Bristol in 2000 suggested one girl in six reaches puberty before the age of eight.

One theory is that puberty is triggered by the hormone leptin, which is produced by fat tissue.

Girls are getting progressively heavier with each generation, and as they carry higher levels of fat, they are also likely to have higher levels of leptin.

Unhealthy lifestyle

Dr Sigman's study focused on three generations of family units, each with a daughter aged 16 to 20, a mother aged 40 to 50, and a grandmother aged 65 to 75.

He found the modern generation eats far more sweets and junk food than its predecessors, but less fresh fruit and vegetables.

Today's young women were also much more likely to travel by car than on foot.

They were also much more to lead a 'coach potato' lifestyle, taking little exercise.

The combination of a poor diet, and an sedentary lifestyle was fuelling obesity rates, said Dr Sigman.

Stress factor

However, he also found evidence that a stressful home life raised the likelihood of an early puberty.

Dr Sigman told the BBC News website that this was possibly an ancient evolutionary response.

"If a girl senses her environment is unstable then it may be that an evolutionary mechanism kicks in to try to ensure that her genes are passed on sooner rather than later," he said.

There is some evidence to suggest that puberty arrives earlier in girls who live with a stepfather.

It is postulated that this might be due exposure to the stepfather's chemical scents, or pheromones, which are likely to have a more profound effect than those associated with a birth parent.

Dr Sigman said it had been assumed that puberty was purely a biological phenomenon influenced by genetics.

"We have not really thought about the possibility that lifestyle factors might influence something so primitive and profound as the arrival of puberty, but it might very well be that they have an impact."

He said early puberty was associated with a number of risks.

Tough time

For instance, girls were vulnerable to emotional disturbances, such as depression, and behavioural problems, such as taking up drinking, smoking or drugs.

Young girls who suddenly started to mature sexually were also less able to control their impulses than those who hit puberty at a later stage, he said. This might in part explain why rates of teenage pregnancy have risen in recent times.

"They tend to work on the hedonistic principle that if it's enjoyable, then it must be right," he said.

Dr Sigman, whos reported was commissioned by Clearasil, said it was important for parents to be aware that puberty might arrive early for their daughters, and to try to talk to them in advance about the changes they would experience.

Mercury Contributes To Alzheimer's Disease!

Scientists have shown that trace amounts of mercury can cause the type of damage to nerves that is characteristic of the damage found in Alzheimer's disease.

The level of mercury exposure used in the test was well below those levels found in many humans with mercury/silver amalgam dental fillings.

The research conducted at the University of Calgary Faculty of Medicine found that exposure to mercury caused the formation of "neurofibrillar tangles," which are one of the two diagnostic markers for Alzheimer's disease.

Previous research has shown that mercury can cause the formation of the other Alzheimer's disease marker, "amyloid plaques."

The scientists also exposed the test nerves to other elements, including aluminum, but found that only mercury caused the damage consistent with Alzheimer's disease.

The research, published in a peer-reviewed medical journal, is accompanied by a video presentation of the effect. Utilizing digital time-lapse photography, this video shows rapid damage to the nerve cells after introduction of minute amounts of mercury. Funding for this video was provided by the International Academy of Oral Medicine and Toxicology (IAOMT).

Dr. Lorscheider produced the visual documentation of the biochemical mechanism by which the introduction of mercury induces hallmark diagnostic markers indistinguishable from those seen in the Alzheimer's diseased brain.

The authors note that, to date, no other material or metal tested, including aluminum, has produced even remotely similar reactions.

The broadcast quality video and animation documenting the biochemical process of mercury on the nerve cells is available to interested members of the press through Miss Karen Thomas, Media Relations, University of Calgary, Faculty of Medicine T: 403-2202945 F: 403-210-8141 Email: thomask@ucalgary.ca

The video can be viewed using Quicktime 4.1 at http://commons.ucalgary.ca/mercury/

The IAOMT was formed to review, support, and disseminate research on the suitability of materials and methodologies used in the dental practice. The IAOMT has funded previous research by Dr. Murray Vimy on the mercury vapors released from mercury amalgam fillings during and after chewing, animal research showing pathophysiological damage to sheep and monkeys from dental amalgam mercury vapor exposure.

Collaborative research with the Calgary authors of this current study and Dr. Boyd Haley at the University of Kentucky demonstrated Alzheimer's disease-like brain damage to rats from inhaled mercury vapor.

Dr. Haley, commenting on the importance of this new documentation, said:

"Seven of the characteristic markers that we look for to distinguish Alzheimer's disease can be produced in normal brain tissues, or cultures of neurons, by the addition of extremely low levels of mercury.

In addition, research has shown that Alzheimer's diseased patients have at least 3 times higher blood levels of mercury than controls. How much more research is necessary before the appropriate regulatory bodies respond with restrictions on the use of mercury-leaking dental amalgam fillings?"

NeuroReport, 12(4):733-737, 2001

This material was copied with permission from http//www.mercola.com.

"These studies are revolutionary," said Dr. Jules Hirsch, physician in chief emeritus at Rockefeller University in New York City, who has spent a lifetime studying the effects of diets on weight and health. "They should put a stop to this era of thinking that we have all the information we need to change the whole national diet and make everybody healthy."

The study, published in today's issue of The Journal of the American Medical Association, was not just an ordinary study, said Dr. Michael Thun, who directs epidemiological research for the American Cancer Society. It was so large and so expensive, Dr. Thun said, that it was "the Rolls-Royce of studies." As such, he added, it is likely to be the final word.

"We usually have only one shot at a very large-scale trial on a particular issue," he said.

The results, the study investigators agreed, do not justify recommending low-fat diets to the public to reduce their heart disease and cancer risk. Given the lack of benefit found in the study, many medical researchers said that the best dietary advice, for now, was to follow federal guidelines for healthy eating, with less saturated and trans fats, more grains, and more fruits and vegetables.

Not everyone was convinced. Some, like Dr. Dean Ornish, a longtime promoter of low-fat diets and president of the Preventive Medicine Research Institute in Sausalito, Calif., said that the women did not reduce their fat to low enough levels or eat enough fruits and vegetables, and that the study, even at eight years, did not give the diets enough time.

Others said that diet could still make a difference, at least with heart disease, if people were to eat the so-called Mediterranean diet, low in saturated fats like butter and high in oils like olive oil. The women in the study reduced all kinds of fat.

The diets studied "had an antique patina," said Dr. Peter Libby, a cardiologist and professor at Harvard Medical School. These days, Dr. Libby said, most people have moved on from the idea of controlling total fat to the idea that people should eat different kinds of fat.

But the Mediterranean diet has not been subjected to a study of this scope, researchers said.

And Barbara V. Howard, an epidemiologist at MedStar Research Institute, a nonprofit hospital group, and a principle investigator in the study, said people should realize that diet alone was not enough to stay healthy.

"We are not going to reverse any of the chronic diseases in this country by changing the composition of the diet," Dr. Howard said. "People are always thinking it's what they ate. They are not looking at how much they ate or that they smoke or that they are sedentary."

Except for not smoking, the advice for a healthy lifestyle is based largely on indirect evidence, Dr. Howard said, but most medical researchers agree that it makes sense to eat well, control weight and get regular exercise.

That is also what the cancer society recommends. Dr. Thun, who described the study's results as "completely null over the eight-year follow-up for both cancers and heart disease," said his group had no plans to suggest that low-fat diets were going to protect against cancer.

Others cautioned against being too certain that a particular diet would markedly improve health, and said that whether someone developed a chronic disease might not be entirely under their control — genetics also plays a role.

David A. Freedman, a statistician at the University of California, Berkeley, who is not connected with the study but has written books on the design and analysis of clinical trials, said the results should be taken seriously.

"The studies were well designed," Dr. Freedman said, "and the investigators tried to confirm popular hypotheses about the protective effect of diet against three major diseases in women."

"But," he added, "the diet studied here turned out not to be protective after all."

The study was part of the Women's Health Initiative of the National Institutes of Health, the same program that showed that hormone therapy after menopause might have more risks than benefits.

In this case, the study addressed a tricky problem. For decades, many scientists have said, and many members of the public have believed, that what people eat — the composition of the diet — determines how likely they are to get a chronic disease. But that has been hard to prove. Studies of dietary fiber and colon cancer failed to find that fiber was protective, and studies of vitamins thought to protect against cancer failed to show an effect.

Many cancer researchers have questioned large parts of the diet-cancer hypothesis, but it has kept a hold on the public imagination. "Nothing fascinates the American public so much as the notion that what you eat rather than how much you eat affects your health," said Dr. Libby, the Harvard professor.

The study found that women who were randomly assigned to follow a low-fat diet ate significantly less fat over the next eight years. But they had just as much breast and colon cancer and just as much heart disease. The women were not trying to lose weight, and their weights remained fairly steady. But their experiences with the diets allowed researchers to question some popular notions about diet and obesity.

There is a common belief that Americans get fat because they eat too many carbohydrates. The idea is that a high-carbohydrate, low-fat diet leads to weight gain, higher insulin and blood glucose levels, and more diabetes, even if the calories are the same as in a higher-fat diet. That did not happen here.

Others have said the opposite: that low-fat diets enable people to lose weight naturally. But that belief was not supported by this study.

As for heart disease risk factors, the only one affected was LDL cholesterol, which increases heart disease risk. The levels were slightly higher in women eating the higher-fat diet, but not high enough to make a noticeable difference in their risk of heart disease.

Although all the study participants were women, the colon cancer and heart disease results should also apply to men, said Dr. Jacques Rossouw, the project officer for the Women's Health Initiative.

Dr. Rossouw said the observational studies that led to the hypothesis about colon cancer and dietary fat included men and women. With heart disease, he said, researchers have found that women and men respond in the same way to dietary fat.

The most recent study follows a smaller one, reported last year, on low-fat diets for women who had breast cancer. That study hinted that eating less fat might help prevent a recurrence. But the current study, asking if a low-fat diet could protect women from breast cancer in the first place, had findings that fell short of statistical significance, meaning they could have occurred by chance.

Dr. Rossouw said he was still intrigued by the breast cancer data, even though it was not statistically significant. The women on low-fat diets had a 9 percent lower rate of breast cancer; the incidence was 42 per thousand per year in women in the low-fat diet group, compared with 45 per thousand per year in women consuming their regular diet.

That could mean that fat in the diet may have a small effect, Dr. Rossouw said, perhaps in some subgroups of women or over a longer period of time. He added that the study investigators would continue to follow the women to see if the effect became more pronounced.

While cancer researchers said they were disappointed by the results, heart disease researchers said they were not surprised that simply reducing total fat had no effect, because they had moved on from that hypothesis.

Of course, Dr. Libby acknowledged, the latest advice, to follow a Mediterranean diet and get regular exercise, has never been tested in a large randomized clinical trial. "If they did a study like that and it was negative," he said, "then I'd have to give up my cherished hypotheses for data."

The low-fat diet was not easy to follow, said Dr. Rowan T. Chlebowski, a medical oncologist at Harbor-U.C.L.A. Medical Center and one of the study's principal investigators. Women were told to aim for a diet that had just 20 percent of its calories as fat, and most fell short.

The diet they were told to follow "is different than the way most people eat," Dr. Chlebowski said. It meant, for example, no butter on bread, no cream cheese on bagels, no oil in salad dressings.

"If a physician told a patient to eat less fat, that will do nothing," he said. "If you send someone to a dietitian one time, that will do next to nothing." The women in the study had 18 sessions in small groups with a trained nutritionist in the first year and four sessions a year after that.

In the first year, the women on the low-fat diets reduced the percentage of fat in their diet to 24 percent of daily calories, and by the end of the study their diets had 29 percent of their calories as fat. In the first year, the women in the control group were eating 35 percent of their calories as fat, and by the end of the study their dietary fat content was 37 percent. The two groups consumed about the same number of calories.

Some medical specialists emphasized that the study did not mean people should abandon low-fat diets.

"What we are saying is that a modest reduction of fat and a substitution with fruits and vegetables did not do anything for heart disease and stroke or breast cancer or colorectal cancer," said Dr. Nanette K. Wenger, a cardiologist and professor of medicine at Emory University School of Medicine in Atlanta. "It doesn't say that this diet is not beneficial."

But Dr. Freedman, the Berkeley statistician, said the overall lesson was clear.

"We, in the scientific community, often give strong advice based on flimsy evidence," he said. "That's why we have to do experiments."

Kevin Stephan, 17, was washing dishes in a restaurant when a customer, Penny Brown, began choking. A volunteer junior firefighter, Kevin stepped up and performed the Heimlich maneuver, according to The Associated Press.

Only when Penny had regained the use of her windpipe did Kevin’s mother recognize her as the nurse who performed CPR on Kevin when he was struck on the chest by a baseball bat in 1999.

As strange as this is — Penny says she can’t think about the incident “without being freaked” by it — such things happen.

Call it the hand of God, a manifestation of “The Force,” or an obscure amendment of the laws of probability, coincidence abounds in a range from the simply odd or the truly bizarre.

A similar tale of reciprocal life-saving occurred in Massachusetts in 1973. Roger Lausier, 13, saw a man struggling in the water off a Salem beach and went into the water to save him.

The man he saved was the husband of Alice Blaise, who had saved Roger from drowning when he was 4.

While you’re hearing that “Twilight Zone” music in your head, here are a couple more well-known classics.

Before filming started for “The Girl from Petrovka,” released in 1974, actor Anthony Hopkins spent a day in London bookstores looking for the George Feifer novel upon which the film was based. After a fruitless search, he headed for the train station, where he found a copy of the book on a bench. Years later, he met Feifer, who identified the find as a copy of the book he had loaned to a friend.

And on the dark side of coincidence lives a Bulgarian woman, an Internet legend, named Martha Martika, whose husband was killed by lightning.

She remarried and her second husband also was killed by lightning.

Perhaps figuring that the third time is the charm, she remarried, but, alas, lightning killed that husband, too.

In a case like that, the superstitious would suspect some kind of a curse.

But even those of us who are dubious when it comes to hexes have to admit that strange things happen.

And all we can do is hope than when the fickle finger of fate points in our direction, it isn’t spouting lightning.

Marian Morris said she hadn't had any practice with CPR in years, but she was interested to see if she "still had it."

"I breathed into its beak, and its dadgum eyes popped open," Morris said. "I breathed into its beak again, and its eyes popped open again. I said, 'I think this chicken's alive now. Keep it warm."'

She said she did not know how to find a pulse on a chicken.

Boo Boo's owners, Jackie and Becky Calhoun, put her in a large cardboard box containing a grain feeder and water. They also placed a heater nearby.

The chicken is called Boo Boo because she is easily frightened. The Calhouns thought Boo Boo was startled and flopped into the pond.