Tens of thousands of diplomats, activists, journalists, businesspeople, celebrities and assorted green hangers-on have descended on the Danish capital of Copenhagen for the U.N.’s annual climate-change summit starting on Monday. Officially, the meeting is known as the 15th Conference of the Parties — in reference to the parties to the U.N. Framework Convention on Climate Change (UNFCCC) — but it might be more accurately called the Last Chance.

To advocates of action on global warming, the Copenhagen summit represents the last, best chance to slow and eventually reverse the growth in greenhouse-gas emissions before climate change begins to spin out of control. To skeptics of climate change, many of whom will attend the conference, Copenhagen is the last defense of another kind — against the growing global momentum to reduce greenhouse-gas emissions, an undertaking they think could cripple the international economy. Either way, it is likely to be the most important international environmental conference in history, its importance bolstered by President Barack Obama’s decision to appear at the end of the summit (initially he had planned to arrive at the start), when the most significant discussions occur and a deal might actually be made. (See TIME’s special report on the Copenhagen conference.)

Although the early and most optimistic expectations for the conference have been blunted, negotiators still have an extraordinary job ahead. They will pore over the endless footnotes and parentheticals of U.N. documents in order to work toward a new global treaty, for which they are expected to generate a framework. “Copenhagen is already a turning point in the international response to climate change,” said UNFCCC chair Yvo de Boer on Dec. 6. Over the next 12 days of negotiations, here are the top five matters to watch for:

1. Will the U.S. lead? The U.S. delegation to climate summits under former President George W. Bush played the spoiler. Not only were American diplomats generally opposed to building a global consensus on reducing carbon emissions, they actively seemed to enjoy gumming up the works, walking out in the middle of negotiations during the Montreal summit in 2005, for instance, and nearly torpedoing the entire process two years ago in Bali. (See pictures of the Himalayan glaciers under threat.)

Under Obama, however, we can expect the U.S. delegation, led by top climate envoy Todd Stern, to play a positive role in the talks. That’s key — the fact that the U.S. wouldn’t play in the past meant that negotiations could rarely move forward, and that there was little leverage for putting pressure on major developing nations like China and India to cut emissions. This year, Obama himself will attend the Copenhagen talks on Dec. 18, the final day of the summit, and he will bring tentative emissions-reduction targets for the U.S. — about a 17% cut in 2005-level emissions by 2020. “What’s significant from our perspective is, after eight years of [the U.S.] not doing anything, President Obama in a year has really tried to move things in the opposite direction,” said Democratic Senator John Kerry, who heads the Senate’s Foreign Relations Committee.

Nevertheless, Obama’s negotiating team will be somewhat hamstrung, because the Senate still has to approve any climate treaty, whether it is signed at the summit or afterward. The range of emissions cuts that Obama will bring to Copenhagen is based on the cap-and-trade bills that have been approved by the House of Representatives, but the Senate may not vote on the bill until the spring. That means any progress made in Copenhagen will be provisional — if the Senate votes down carbon caps next year, things could fall apart.

Even so, the emissions cuts the U.S. is willing to agree to are still far short of what the European Union is promising, and far less than what developing nations are demanding. “Overall the level of ambition is too low,” says Alden Meyer, director of strategy and policy at the Union of Concerned Scientists. “That leaves us with low expectations for the summit.”

2. Will China and India follow? Historically, the U.S. may be the world’s biggest carbon emitter — responsible for more than a quarter of the man-made CO2 in the atmosphere — but developing nations led by China and India will be responsible for the majority of future emissions. At the same time, those nations still have low per capita emissions, and under the Kyoto Protocol, they haven’t been required to take any verifiable actions to control emissions. Until recently, they haven’t shown much interest in doing so, but that may now be changing. (See pictures of penguins at risk.)

China recently announced that Premier Wen Jiabao would attend the Copenhagen summit, and that he would bring a Chinese promise to reduce carbon intensity — essentially a measure of energy efficiency — at least 40% by 2020. Shortly afterward, India followed up with its own pledge to cut carbon intensity 20% to 25% by 2020. “If India wants to lead the developing nations, we have to offer something,” said Jairam Ramesh, India’s Environment Minister, in a speech to lawmakers on Dec. 3. “India stands for a comprehensive, equitable agreement.”

Sounds pretty good. But as Michael Levi, a climate-change expert for the Council on Foreign Relations, was quick to point out, both China and India will almost certainly improve their carbon intensity as they continue to develop, so their new pledges may hardly be better than business as usual. More worrying, both countries are resisting making their domestic pledges measurable and verifiable under an international treaty — unless they receive more climate aid. In other words, the rest of the world would need to take Beijing and New Delhi’s word for it — something Washington is dead set against. Expect sharp negotiation on this point.

3. The two-step tango. Back in 2007 on the sunny Indonesian island of Bali, negotiators worked out the “Bali road map,” a series of steps toward a successor to the Kyoto Protocol that would guarantee a new global climate treaty by the 2009 conference in Copenhagen. Well, road map or not, the international community got a bit delayed — in part due to the fact that Obama has had less than a year to turn around U.S. climate policy — and no one expects an actual treaty to be negotiated and signed in Copenhagen.

Instead we may have what Danish Prime Minister Lars Lokke Rasmussen has called the “two-step approach.” In the first step, world leaders would converge on a “political agreement” in Copenhagen that would emphasize the importance of fighting climate change and perhaps set out global temperature targets for the future. Work would also be done to form as much of the legal architecture of a deal as possible — such as agreements on deforestation, on financial aid for adaptation, perhaps on target levels. Afterward, major countries like the U.S., Australia and Canada would have time to pass domestic carbon caps at home. In the second step, at a later meeting — either a special summit or next year’s COP in Mexico City in December — the numbers could be dropped into a treaty and quickly signed. In this way, “Copenhagen can be a resounding success,” said de Boer before the conference began.

But if Copenhagen really only produces another dry political statement about the need to deal with climate change, well, that’s already been done. And a lot can go wrong between the first step and the second step. The U.S. Senate could refuse to support domestic carbon caps, which might scuttle the entire treaty process; or other skeptical countries, such as Russia or Saudi Arabia, could likewise throw a wrench in the process. But most importantly, after the summit, momentum could dissipate. The Copenhagen meeting represents a rare, fleeting moment when the entire world will be focused on climate change. “Will you lose the potential will to negotiate a legally binding treaty after the spotlight is off Copenhagen and the ministers and heads of state go home?” asks Meyer.

4. Seeing REDD on deforestation. The loss of tropical forests plays a major role in climate change, contributing about 15% of global greenhouse gases, according to the most recent estimate. But deforestation has an environmental impact that goes beyond climate change — tropical forests are home to a wealth of diverse species, and when the trees are lost, wildlife follows.

Slowing the rate of deforestation has a double benefit, but currently there’s no mechanism for developing countries to earn carbon funding by keeping their trees. That could change in Copenhagen with the inclusion of REDD — Reduced Emissions from Deforestation and Degradation. The plan would allow tropical nations like Brazil and Indonesia to earn carbon credits by pledging to keep their forests standing — just as developing nations can already earn carbon money by switching to renewable power or cleaning up a polluting factory. “There is an enormous opportunity to be seized here,” says Duncan Marsh, director of international climate policy at the Nature Conservancy.

What makes forestry proponents so optimistic is that REDD, much more so than any other part of a potential climate deal, has broad support from both developed and developing countries. Major developing powers, including Brazil and Indonesia, once suspicious that REDD would require them to surrender sovereignty over their forests, are now eager to be involved. At the same time, developed countries see avoided deforestation as a cheap and easy way to offset their own emissions — the cap-and-trade bill approved by the U.S. House in June includes specific provisions for REDD offsets. “REDD really could be one of the success stories out of Copenhagen,” says Marsh.

5. Financing adaptation. Combating climate change isn’t just about reducing carbon emissions. Global warming is coming even if we do act fast, and developing nations will bear the brunt of the impact. That’s why another leg in the global treaty will address funding to help developing nations adapt to climate change — whether that means the building of seawalls, aid for agriculture during increasing droughts or the ability to better respond to natural disasters. “We need clarity on long-term finance for developing countries,” says de Boer.

For a long time, no one could agree on how much money would need to be spent. The White House has said that the Copenhagen accord should be able to mobilize at least $10 billion a year to support adaptation and mitigation in developing nations, while British Prime Minister Gordon Brown has said he expects developed countries to ultimately spend up to $100 billion a year for adaptation. The White House is now saying there is an “emerging consensus” on the $10 billion–per-year figure, at least by 2012, but it isn’t clear how or who would distribute the money. Developed countries generally prefer the World Bank or another existing institution to handle it, while many developing countries want an entirely new body. “Will aid for developing countries be part of overall development aid, or in a legally binding treaty or some other basket?” says Meyer. No one knows yet.

As the talks begin in Copenhagen, there’s reason for climate-change advocates to feel optimistic — for the first time world leaders will be sitting down to focus solely on global warming — and reasons to worry that everything will collapse. The one thing we know is that this summit will help decide whether the world takes on climate change, or continues risking business as usual. “This is our last chance to avoid a dangerous 2°C of warming,” says Dan Lashof, the director of the Natural Resource Defense Council’s Climate Center. One way or another, now is the time to act.

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In February 2009, Australia’s Environment Minister Peter Garrett made a depressing announcement. The Christmas Island pipistrelle bat — an inch-long winged creature no heavier than five grams — was about to go extinct. Articles about its imminent demise were accompanied by photos of the bat’s minuscule body, barely big enough to embrace the full diameter of a human finger. In February, there were estimated to be just 20 bats left. One was seen fluttering around the island in August, but there have been no sightings since.

If the Christmas Island pipistrelle is truly gone, it will be the 23rd Australian mammal species to have become extinct in the past 200 years. The last to perish was the crescent nail-tail wallaby — a miniature wallaby the size of a hare — which disappeared from western and central Australia in 1956. Twenty years earlier, in what was perhaps Australia’s most infamous extinction, the Tasmanian tiger met its end. The largest carnivorous marsupials to live in modern times, the tigers, which looked like large, striped dogs, were suspected of eating sheep, and a group of wool merchants put out a bounty in return for the dead animals. Those that were not hunted down and killed in Australia’s southernmost state were chased out of their natural habitat by domesticated dogs. (See the top 10 animal stories of 2009.)

The accumulation of tragedies like these has given Australia the shameful distinction of having the worst mammal-extinction record in the world. Half of the mammals that have vanished from the planet in the past two centuries have been in Australia. And though the continent is hardly the only place grappling with die-offs — many biologists have conceded that a mass wave of extinctions is now sweeping the globe — as the list of Australia’s endangered species continues to grow longer, scientists there are looking for ways to put an end to the trend.

Mike Archer, a professor at the School of Biological, Earth and Environmental Sciences at the University of New South Wales (UNSW), has long been a proponent of domesticating Australia’s unique wildlife to keep it from disappearing. Archer has had sugar gliders employ his shoulder as transport, shared a bed with a cucumber-loving quoll and battled a swamp wallaby over a roast chicken. While he concedes that not all native animals make great pets (wombats and koalas come to mind), others do, and Archer is hoping that the government will start to legalize ownership of more native pets. “No animal that has ever entered [humans'] inner circle has become extinct,” he says. “When you value something and have an emotional connection with it … it simply doesn’t disappear.”

It’s a strategy that has worked before in Australia, albeit on a smaller scale. In 1987, rainbow fish were considered to be forever gone from the lakes in northern Queensland — their sole habitat. In a move to save them, fish enthusiasts collected the species for their personal aquariums, and when the Queensland fisheries caught on, the pet fish were used to start breeding programs. (See the top 10 new species discovered in 2009.)

Today, most Australians’ interactions with the continent’s native species are limited to zoos — many wouldn’t know a quoll from a bandicoot, or a numbat from a bilby. But Archer’s plan seems to be gaining some traction. The Rural Industries Research and Development Corporation (RIRDC), a federal government organization, will release a study next year considering the potential to use threatened eastern quolls — native, cat-sized marsupials with white spots and bushy tails — as household pets, on the basis that they are rare and could be suited to an urban habitat.

Rosalie Chapple, a professor at the Institute of Environmental Studies at UNSW and a key author of the RIRDC report, cautions about the implications of utilization of wild animals as pets. “It should be based on a conservation imperative and not a commercial industry imperative,” says Chapple. “The well-being of the animal must be taken into account.” A native-mammal pet industry would need guidelines on living and food requirements for quolls, as well as a lot of paperwork for licensing and regulation.

Chapple is also wary about contributing to an overloaded pet industry. In the Australian state of New South Wales alone, over 63,000 cats and dogs are abandoned every year, and a recent bill brought before the state parliament sought, unsuccessfully, to ban the sale of cats and dogs from pet shops. “With cats and dogs, we already see gross welfare issues,” says Daniel Ramps, a senior research fellow with the Australian Wetlands and River Center at UNSW who is vehemently opposed to keeping quolls as pets. “Quolls have much more specific requirements. They need a lot of space,” Ramps says. “By encouraging a pet industry you are essentially opening quolls up to abuse.”

Ramps and other opponents of domesticating native species argue that cats and dogs have become domesticated over thousands of years of evolution, but quolls and other animals like them have a long way to go before they learn to share indoor spaces with humans. “[The quoll is] a predator,” Ramps says. “Its instincts aren’t able to be maintained in a captive environment.”

Archer dismisses the argument. “When I was given a western quoll as a kitten, we had a very strong bonding experience. It was so cute, covered in little white spots, with these huge eyes,” he recalls. And while he feels quolls and people would get along just fine, he is blind to the charms of less exotic housemates while his cause gains more traction. When asked if he has any pets now, Archer laughs. “We were waiting and waiting to legally own a quoll and then my kids told me, ‘Let’s face it, Dad, if we keep this up we will never know what it is to own a pet.’ Now we have two dogs.”

See TIME’s special report on the environment.

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If you are among the thousands of American women who have survived breast cancer, you probably find yourself thinking twice about everything you do — what you eat, how much you exercise — to ensure that you don’t increase your risk of developing another tumor. It’s a natural response to a difficult diagnosis, but it can be challenging, especially when it comes to diet: most breast tumors are driven by the hormone estrogen, but estrogen is frequently found in many popular foods, from some types of milk and yogurt to breakfast bars to tofu and those addictive edamame beans.

The common culprit is soy, a plant that contains chemicals with estrogen-like and anti-estrogenic properties — making it a nutritional minefield for breast-cancer survivors. While Western diets are relatively low in soy — compared with the typical diet in Asia, where people eat soy daily — the percentage of Americans consuming soy at least once a week increased from 15% in 1997 to 28% in 2003. In the meantime, studies on the effect of soy on breast-cancer recurrence and mortality have been conflicting, with some showing that it can reduce risk, while others show an elevated rate of recurrent disease among frequent consumers of soy. (See breast cancer’s fundraising warrior.)

Now the largest study to date on soy’s effect on breast cancer suggests that eating soy, even in large amounts, may not be harmful after all, and may even reduce recurrence and death from the disease. But while the findings are intriguing, not all doctors are ready to tout the benefits of tofu.

Analysis of the study, conducted in China between 2002 and 2006, is ongoing, but researchers based at Vanderbilt University and the Shanghai Institute of Preventive Medicine report data from the first four years of follow-up (total follow-up was five years) in the current issue of the Journal of the American Medical Association. The 5,042 women enrolled in the study were all breast-cancer survivors, ages 20 to 75, and they consumed soy from naturally occurring sources, such as tofu or soybeans none of the women took soy supplements. They fell into two groups based on soy intake: those who consumed more than 15.3 g of soy protein a day, or as much as would be found in three-quarters of a cup of edamame beans, and those who consumed less than 5.3 g per day, less than what is contained in a half-cup of soy milk, which has 7 g of soy protein. (Read “The Mammogram Melee: How Much Screening Is Best?”)

Among the women consuming the most soy, the risk of death from breast cancer four years after diagnosis was 7.4% and the risk of recurrence was 8%. Women in the lower soy-intake group had higher risks: a 10.3% risk of death from breast cancer and an 11.2% risk of recurrence. “I think based on our study, I am quite comfortable saying that soy food, particularly a moderate amount, is safe, and potentially beneficial,” says the study’s lead author, Dr. Xiao-Ou Shu, an epidemiologist at Vanderbilt.

Other breast-cancer experts agree that soy intake may not be harmful for cancer survivors, but they draw the line at saying it can reduce cancer incidence or mortality. “There is no take-home message here to go out and eat as much soy as you can,” says Dr. Larry Norton, medical director of the Evelyn Lauder Breast Center at Memorial Sloan-Kettering Cancer Center in New York City.

Norton notes that the study was not a randomized clinical trial of soy consumption. That is, rather than randomly assigning breast-cancer survivors to consume or not consume various amounts of soy, then following those participants to see whether they developed recurrent tumors, the study looked retrospectively at women’s self-determined soy-eating habits. The randomized clinical trial is the gold standard upon which medical practice is determined, and the only kind of trial that gives scientists confidence that other variables are not confounding their results. In the new study, for example, the authors note that the women eating the highest amounts of soy were also more likely to have received chemotherapy to treat their disease and to eat vegetables and exercise regularly — all factors that may contribute to lower breast-cancer risk. Shu and her colleagues adjusted for these variables, but, says Norton, “with any observational study, you don’t know what else is going on.”

Although not all experts are convinced that it’s safe to begin advising women to add soy to their diet, they agree that there is no need to avoid soy altogether. “What I’ve been telling my patients right now is that soy as part of a healthy balanced diet is safe. But I would avoid trying to eat a totally soy-based diet or taking a soy supplement. You have to be careful in not extrapolating beyond the study,” says Dr. Richard Lee, medical director of the Integrative Medicine Program at MD Anderson Cancer Center in Houston.

See pictures of the faces of breast cancer.

See the new mammography guidelines in TIME’s Top 10 Everything of 2009.

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The controversy over e-mails stolen from global-warming researchers at the Climatic Research Unit (CRU) at Britain’s University of East Anglia has become so divisive that there is even disagreement over what to call it.

Skeptics of global warming, who have long considered climate change a fraud, refer to the incident as “Climategate,” with obvious intimations of scandal and cover-up. Advocates of action on warming call it “Swifthack,” a reference to the 2004 character attacks on presidential candidate Senator John Kerry by the group then known as Swift Boat Veterans for Truth — in other words, an invented scandal propagated by conservatives and the media that does nothing to change the scientific case for climate change. (See TIME’s special report on the environment.)

The truth is that the e-mails, while unseemly, do little to change the overwhelming scientific consensus on the reality of man-made climate change. But they do hand a powerful political card to skeptics at the start of perhaps the most important environmental summit in history. Still don’t know what to make of it? If you’re struggling to untangle the details of the e-mail controversy, here are five key things you need to know:

1. How were the e-mails leaked? On Nov. 17, administrators of the website RealClimate, a blog about climate science written by top researchers, discovered that unknown hackers were attempting to upload onto the blog more than 1,000 e-mails apparently sent by and to scientists at University of East Anglia’s CRU. The CRU is one of the most important climate-research centers in the world, and one of a handful of scientific agencies that keep the global temperature records used in most major climate models. Officials at East Anglia soon confirmed that electronic theft had occurred and that the e-mails were genuine. By the end of the week, they were widely available on the Internet. (Facebook users, comment on this story below.)

In early December, the e-mail controversy was still burning up the blogosphere, as international negotiators gathered at the Copenhagen climate summit. The head of the CRU and author of several incriminating e-mails, environmental scientist Phil Jones, has stepped down temporarily from his post while University of East Anglia conducts an independent inquiry into the e-mail controversy. The investigation will be led by Muir Russell, a prominent Scottish academic and civil servant. Meanwhile, Pennsylvania State University (PSU) announced it would conduct its own inquiry into the e-mails, after PSU climatologist Michael Mann also emerged as an author of e-mails that were central to the controversy. (See how global warming is threatening penguins.)

2. What exactly do the e-mails say? The more than 1,000 e-mails dating back some 13 years contain a range of information — everything from the mundanities of climate-data collection to comments on international scientific politics to strongly worded criticisms of research by climate-change doubters. It is mainly the last point that has skeptics crying foul. In one e-mail, sent to Mann from Jones, the topic is a pair of papers that criticize the case for man-made global warming; Jones wrote that he and his colleagues would be sure to keep the papers out of consideration for the forthcoming climate assessment by the Intergovernmental Panel on Climate Change (IPCC), “even if we have to redefine what the peer-review literature is.”

In another e-mail exchange, Mann and Jones discuss ways to pressure an academic journal Climate Research to stop publishing submissions from climate skeptics, with Mann suggesting that they consider encouraging colleagues not to submit papers to the journal until it changes its editorial stance. Jones also wrote repeatedly about rebuffing requests by climate skeptics for raw temperature data from CRU, and seemingly encourages his colleagues to delete e-mails concerning a Freedom of Information request for the data.

In other e-mails, scientists appear to have trouble reconciling recent temperature data with the warming expected from climate models. And overall, the correspondence evinces climate scientists’ outright scorn for global-warming skeptics; in one message, Ben Santer, a researcher from Lawrence Livermore Laboratory offers — presumably in jest — to “beat the crap out of” a leading skeptic.

See a climate-change edition of the Acoustic Weekly News.

Read “Floods and Droughts: How Climate Change Is Impacting Africa.”

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The major U.N. summit on climate change opened Monday in Copenhagen, but the big environmental news was made across the Atlantic in Washington. In an afternoon press conference, Environmental Protection Agency (EPA) Administrator Lisa Jackson announced that the agency had finalized its finding that greenhouse gases, including carbon dioxide, pose a threat to human health and welfare.

The ruling allows the EPA to begin regulating greenhouse-gas emissions from power plants, factories and major industrial polluters, although the precise details of that regulation have yet to be worked out. “The threat is real,” said Jackson. “If we don’t act to reduce greenhouse-gas emissions, the planet we will leave to the future will be very different than the one we know today.” (See TIME’s special report on the environment.)

Jackson’s announcement was the final step in a response that has been nearly three years in the making — since April 2007, when the Supreme Court ruled in Massachusetts v. EPA that the Clean Air Act gives the EPA the authority to regulate emissions of greenhouse gases, if they are indeed a threat to human health and welfare. At the time, the court directed the agency to review the latest science on climate change in order to make a determination.

Under former President George W. Bush, the EPA largely punted on the question, even burying analysis from its own scientists in the waning months of that Administration. When President Barack Obama took office, he directed the new EPA to kick-start the regulation process — nearly 11 months and 380,000 public comments later, the agency is now poised to regulate CO₂ as a pollutant. “This cements 2009′s place in history as the year the U.S. government began seriously addressing the challenge of greenhouse-gas pollution,” said Jackson.

Although the announcement had been in the pipeline for a while, the timing was appropriate, with Copenhagen getting under way. The EPA ruling is a signal to other countries that the U.S. is prepared to contribute to a climate treaty, and it is a useful tool for Obama, who will participate in the Copenhagen summit on Dec. 18, its final day. “In light of the EPA endangerment finding, the President’s appearance in Copenhagen will carry even more weight, because it shows that America is taking this issue very seriously and is moving forward,” said Senator Barbara Boxer, head of the Senate Environment and Public Works Committee, in a statement.

It is not clear what the EPA’s decision will mean practically for major emitters. Jackson said she did not have a timetable for when the agency would publish a detailed plan to reduce greenhouse-gas emissions, and both Jackson and Obama have said repeatedly that they would prefer legislative action — in the form of a carbon cap-and-trade bill — over top-down regulation. The House has already passed a bill that would cap U.S. carbon emissions at 17% below 2005 levels by 2020, and the Senate is considering similar legislation. The threat of EPA regulation might be enough to nudge the Senate in the right direction. “We still need to pass a Senate bill because we need a long-term, clear signal about the effort we will undertake to cut carbon,” said Jack Schmidt, international climate policy director for the Natural Resources Defense Council.

For their part, business groups and many conservatives remain even more opposed to the possibility of EPA regulation of greenhouse gases than they do to a cap-and-trade bill. They say CO₂ is far more prevalent than any other pollutant the EPA has ever attempted to regulate under the Clean Air Act and that top-down regulation would lay a heavy burden on U.S. business. “An endangerment finding from the EPA could result in a top-down command-and-control regime that will choke off growth by adding new mandates to virtually every major construction and renovation project,” said U.S. Chamber of Commerce President and CEO Thomas J. Donohue.

Such a command-and-control regime is a long way off, and may never happen — especially if cap and trade is finally passed. But with the most important environmental summit in history kicking off, the EPA’s news couldn’t come at a better time for greens. “Every positive announcement will improve our chances of staying below the 2°C target,” said Danish Minister Connie Hedegaard, who is presiding over the Copenhagen summit. “But we all know only too well, we are not there yet.”

See pictures of the world’s most polluted places.

See pictures of the effects of global warming.

(CNN) — Psychological trauma isn’t just mental — it may leave a visible trace in a child’s brain, scientists say.

A new study published in the Journal of Pediatric Psychology found that children with symptoms of post-traumatic stress had poor function of the hippocampus, a part of the brain that stores and retrieves memories.

This is the first study to use functional magnetic resonance imaging, or fMRI, to look at the function of the hippocampus in youth with symptoms of post-traumatic stress, researchers said. The findings are in line with what has been previously found in adults.

The study was led by Dr. Victor Carrion, and the senior author was Dr. Allan Reiss, both at the Center for Interdisciplinary Brain Sciences Research at Stanford University School of Medicine.

Post-traumatic stress disorder is a condition that children and adults develop in response to a traumatic event. Intrusive memories, increased anxiety and emotional arousal are some of the symptoms, and typically they begin within three months of a traumatic event, according to the Mayo Clinic.

Of youths who have experienced a traumatic event, 3 percent to 15 percent of girls and 1 percent to 6 percent of boys could get a PTSD diagnosis, according to the U.S. Department of Veterans Affairs.

By contrast, an estimated 6.8 percent of the adult American population has had PTSD at some point, the department said.

The condition looks slightly different depending on age — young children may display “post-traumatic play” in which they repeat themes of the trauma, whereas adolescents may incorporate aspects of the trauma into their lives, carrying a weapon for instance. Also, adolescents are more likely than younger children or adults to exhibit impulsive and aggressive behaviors, according to the Department of Veterans Affairs.

Although the study shows only an association — not a cause-and-effect relationship — between this brain damage and post-traumatic stress, the study authors believe the abnormal hippocampus findings are the consequence of post-traumatic stress, not a risk factor for it, said co-author Brian Haas.

That explanation makes sense, given what is known about post-trauma, said Dr. Sanjay Gupta, CNN’s chief medical correspondent and a neurosurgeon. He was not involved in the study. One of the reflexes that can come after a traumatic event is forgetting it, meaning perhaps “the hippocampus shrinks to fade away memories,” he said.

“The flip side of it is that you have trouble with memory overall,” he said. “You wish you could just forget the event.”

Animal studies have shown that brain damage in mice occurs after a trauma has been induced, Haas said.

Gupta said the study is important as researchers try to pinpoint what happens in the brain anatomically when a person has a trauma-related disorder.

The study looked at 27 people ages 10 to 17, which is a reasonable sample size for an imaging study of how the brain functions, said Lisa Shin, associate professor of psychology at Tufts University, who was not involved in the study. Participants were divided into 16 young people who had symptoms of post-traumatic stress disorder and 11 normal youths.

Scientists scanned the participants’ brains while they completed a verbal memory test. They read a list of words, then looked at a similar set with additional words and had to remember which words were on the original list.

Participants with PTSD symptoms did worse on the recall portion and showed less activity in the hippocampus during that time than the control group members.

The young people whose hippocampus functioning was the worst were more likely to experience avoidance and numbing symptoms of PTSD — having difficulty remembering the trauma, feeling isolated and not displaying emotion.

Previous research had found that adults with PTSD tended to have a smaller hippocampus volume.

Measuring neural functioning in the brain can indicate the extent of symptoms that a person is experiencing after a PTSD diagnosis, and reflect the effectiveness of therapy, Haas said. In other words, if the hippocampus is functioning better, that may mean the treatment is working.

If there is enough evidence that the hippocampus is involved in PTSD, a treatment could, in theory, be targeted to it, Shin said. There is some indication that treatment with serotonin reuptake inhibitors, or SSRIs, is associated with increased volume of the hippocampus in adults with PTSD, but not greater function, she said.

Shin and colleagues are working on a twin study to explore whether brain abnormalities in people with PTSD were pre-existing risk factors or the result of PTSD.

Washington (CNN) — The Senate on Tuesday rejected an amendment to tighten restrictions on federal funding for abortion in the sweeping health care bill it is debating.

On a 54-45 vote, the chamber agreed to table the amendment, which effectively killed it from further consideration. Rejection of the amendment means the Senate health bill, if approved with the current abortion language, would differ from more restrictive language in the House version of the bill passed last month.

The amendment filed Monday by Sens. Ben Nelson, D-Nebraska, and Orrin Hatch, R-Utah, mirrored language in the House bill that prevents any health plan receiving federal subsidies from offering coverage for abortion.

Anti-abortion legislators said the amendment would maintain the current level of restriction by preventing any federal funding for abortion except in the case of rape, incest or a threat to the life of the mother.

Hatch argued Tuesday that the Senate proposal as originally written provides a loophole for the use of federal money to subsidize health insurance that would cover abortion.

“Taxpayers should not be called upon to pay for abortion,” Hatch said.

Other GOP senators said the strong opposition by millions of Americans to federal funding for abortion should be respected by passing the amendment to tighten restrictions.

Nelson had warned that without the amendment, he could vote against ending debate on the bill.

Senate Majority Leader Harry Reid, D-Nevada, needs 60 votes to close debate on the bill and bring it to a vote, and 51 votes for final passage. In the Senate, the Democratic caucus has 60 members. If Nelson or any other Democrats break with the caucus, Reid will need some Republican support to move forward.

Senate Republicans unanimously oppose the bill.

Opponents of the tougher language argued that the amendment would expand the current level of restriction because women receiving coverage under a federally subsidized health care plan would be barred from purchasing abortion coverage with their own money.

“Why are women being singled out here? It’s so unfair,” said Sen. Barbara Boxer, D-California, adding there is no medical procedure for men that cannot be purchased with private funds.

Sen. Debbie Stabenow, D-Michigan, said the real kikil of the amendment is to deny women covered by government-funded health care the right to get an abortion.

“Let’s keep federal policy in place that does not allow federal funding for abortion but respects the women of this country,” Stabenow said.

Maine’s two Republican senators — Olympia Snowe and Susan Collins — both joined Democrats in voting to table the amendment, while seven Democrats voted with the chamber’s other 38 Republicans against killing the proposal.

The House adopted its restrictive language as part of a last-minute concession to anti-abortion legislators who threatened to defeat the health care bill without a vote on the provision.

Reid, D-Nevada, said earlier Tuesday he would continue to work with Nelson on the issue if the Nebraska lawmaker’s amendment failed.

“I’m happy to work with him,” Reid said. “If, in fact, he doesn’t succeed here, we’ll try something else.”

If the Senate eventually passes a bill that gets merged with the House version, the abortion language will be a crucial issue. An anti-abortion bloc in the House threatens to reject a bill without the tougher language adopted by the chamber, while a liberal-progressive House bloc has said it won’t accept a bill with the more restrictive provision.

Also on Tuesday, liberal and moderate Democrats reached a “broad agreement” on the public option portion of the Senate health care bill, Reid said.

Without revealing any details, Reid said the negotiating senators had reached an agreement that “moves this bill way down the road.”

Two Democratic sources said the deal includes proposals to replace the public option by creating a not-for-profit private insurance option overseen by the federal Office of Personnel Management, much like the current health plan for federal workers, and another allowing people 55 and older to buy into Medicare coverage that currently is available to those 65 and older.

But Sen. Russ Feingold of Wisconsin, one of 10 Democratic senators working on the deal, said in a statement released after Reid’s announcement that he would not “support proposals that would replace the public option in the bill with a purely private approach.”

CNN’s Dana Bash, Evan Glass and Deirdre Walsh contributed to this report.

(Health.com) — Women with breast cancer who eat more soy are less likely to die or have a recurrence of cancer than women who eat few or no soy products, according to a new study.

In the past, physicians have often warned breast cancer patients not to eat soy. The new research represents “a complete turnaround” from the previous understanding about the link between soy consumption and breast cancer, says Sally Scroggs, a registered dietician and senior health education specialist at M.D. Anderson’s Cancer Prevention Center in Houston, Texas.

“We have gone from saying, ‘No soy for breast cancer survivors’ to, ‘It’s not going to hurt,’” Scroggs says. “Now it looks like we can say, ‘It may help.’”

The study looked at more than 5,000 women in China who had undergone a mastectomy; they were followed for about four years. The women who consumed the most soy protein (about 15 grams or more a day) had a 29 percent lower risk of dying and a 32 percent decreased risk of breast cancer recurrence compared to the women who consumed less than about 5 grams of soy protein a day, according to the study, which appears in the December 9 issue of the Journal of the American Medical Association. The National Cancer Institute and the U.S. Department of Defense’s Breast Cancer Research Program funded the study.

Health.com: How to take care of yourself after breast cancer surgery

Women who ate between 9.5 and 15 grams of soy protein saw nearly the same decrease in risk as the women who ate more than 15 grams. In fact, the researchers found no additional benefits to eating more than 11 grams of soy protein a day. (An 8-ounce glass of soy milk and a cup of shelled edamame contain about 7 and 14 grams of soy protein, respectively.)

In all, 534 women had a breast cancer recurrence or died from breast cancer during the study period.

Soy foods–such as milk, tofu, and edamame–are rich in naturally occurring estrogens (especially isoflavones) that can mimic the effects of estrogen in the female body. Because the most common types of breast cancer depend on estrogen to grow, experts once feared that soy isoflavones could stimulate the estrogen receptors in breast-cancer cells, even though the estrogens in soy are much weaker than those produced by the body.

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The current study suggests the exact opposite: Soy may actually reduce the amount of estrogen that’s available to the body.

“Soy isoflavones may compete with estrogens produced by the body. Soy isoflavones may also reduce the body’s production of estrogen, and increase clearance of these hormones from the circulation–all of which together reduce the overall amount of estrogen in the body,” says the lead author of the study, Dr. Xiao Ou Shu, M.D., Ph.D., a cancer epidemiologist at the Vanderbilt-Ingram Cancer Center of Vanderbilt University Medical Center in Nashville, Tennessee.

Shu says, however, that factors beyond estrogen may be at work. Other components of soy foods, such as folate, protein, calcium, or fiber (or some combination thereof) may also be responsible for the health benefits reported in the study, she says.

Health.com: New breasts to go with my cancer-free life

The new findings, which seem to contradict what many women have heard from their doctors over the years, could prove perplexing for women such as Andrea Mulrain, 44, a former music executive who was first diagnosed with breast cancer 10 years ago.

After her diagnosis, Mulrain’s doctors told her to steer clear of all soy foods because these foods could encourage the growth of cancer cells. Mulrain had estrogen-sensitive breast cancer, which means that estrogen helps the cancer grow.

Her doctors eventually softened their stance a bit, and said she could consume soy in moderation. “I pretty much avoided soy for 10 years after diagnosis but recently was told it was OK to have soy in moderation as long as I read the labels and make sure it’s not the main ingredient in any food,” says Mulrain, who is currently being treated for a recurrence.

In the study, the association between soy consumption and lower risk of death and cancer recurrence was seen in women like Mulrain with estrogen-sensitive breast cancers, and in women taking tamoxifen, a drug designed to prevent cancer recurrence by blocking the effects of estrogen in the breast tissue.

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Despite the study’s findings, the final verdict on soy and breast-cancer recurrence is not yet in, according to an accompanying editorial written by Dr. Rachel Ballard-Barbash, M.D., of the National Cancer Institute in Bethesda, Maryland, and Marian L. Neuhouser, Ph.D., of the Fred Hutchinson Cancer Research Center in Seattle, Washington.

The follow-up period in the new study was relatively short, they say, and breast-cancer diagnosis and treatment may be different in China compared to the United States. Similarly, there may be differences in the types of soy foods that Chinese and American women eat. (In general, Chinese women consume significantly more soy than American women.)

More studies are needed to confirm these findings, especially as they apply to women with estrogen-sensitive breast cancer or those who take drugs such as tamoxifen to keep breast cancer at bay, say Ballard-Barbash and Neuhouser. Still, they say, “Patients with breast cancer can be assured that enjoying a soy latte or indulging in pad thai with tofu causes no harm, and when consumed in plentiful amounts may reduce risk of disease recurrence.”

The study should be reassuring to women who have been trained to steer clear of soy, says Scroggs. “Don’t freak out if there is some tofu mixed in with your vegetables at an Asian restaurant,” she says.

Health.com: Breast cancer — What should I do if I′m high risk?

Her soy prescription for breast-cancer survivors? “Eat soy in moderation, and your soy proteins should come from foods, not concentrated supplements,” she says. “Soy is a complete protein so it is high in fiber and has a place in a healthy, balanced diet.”

Eating more soy is beneficial because it tends to replace less healthy foods in people’s diets, Scroggs says. “When people are eating soy protein, they are likely eating less of something else, such as red meat,” she says.

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New York (CNN) — In the rare cases when the H1N1 virus kills, scientists have found, it penetrates deep into the lungs, creating widespread damage — a pattern similar to what killed millions during previous flu pandemics in 1918 and 1957.

The New York Office of Chief Medical Examiner examined medical records, autopsy reports and microscopic slides of 34 people with H1N1 who died between May 15 and July 9, 2009, during the early days of the pandemic.

The report found that among those deaths, inflammation and damage in the lungs extended all the way to the alveoli, tiny sacs at the farthest end of the lungs’ airways.

“Generally, flu stays in the upper airways,” said Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases. “What this shows is clearly this virus has capability of infecting and causing inflammation and destruction of cells from the trachea, all the way down into smaller cells of the lungs.

“The cells of the lung get directly attacked by the virus,” said Fauci.

The damage appears in computerized scans as opaque patches that normally would not appear in the lungs, and which obstruct lung function.

Get complete coverage of ˑN1 — Fighting the flu

Echoing previous reports, the study, published online in the Archives of Pathology and Laboratory Medicine, also revealed that 91 percent of those who died were people with underlying health problems, and most occurred in people between 25 and 49 years old.

More than half of the deaths were caused by bacterial pneumonia.

“The secondary bacterial infection evokes inflammation,” said Dr. William Schaffner, professor in the Division of Infectious Diseases at Vanderbilt University School of Medicine. “It socks it in the lung and all of a sudden the lung as an organ can’t do its principal job.”

Obesity was a factor in 72 percent of ˑN1 deaths, a finding that has caused concern among infectious disease experts.

“That was a striking finding,” said Schaffner. “It contributes in a very material way to what we know about risks for a severe outcome with H1̍ infection. We are keeping an eye on obesity as a risk factor for H1̍ death.”

Track the H1N1 virus in your state

The study gives interesting insight into the mechanism behind H1N1 deaths, but will not change the current response to the virus, said Fauci.

(CNN) — Jordan Pittard, 14, remembers feeling anxious about his father being deployed with the U.S. Army in Iraq from 2006 to 2007. His mother, Lucille, a teacher, admits struggling to have enough time to work, take care of the house and talk enough to her kids.

“There was nobody big to look up to,” Jordan said. “Sometimes when my mom was away, there wasn’t anybody else to help me with my homework, something personal like that, or throw a football with me.”

The mother and son participated in a new study that suggests youth from military families may have higher stress levels and emotional problems than other adolescents and teens.

The study was published in the journal Pediatrics just days after President Obama announced his decision to send 30,000 more troops to Afghanistan.

Researchers used a scale that measures anxiety symptoms as they interviewed children and parents about emotional and behavioral health. The study is not diagnostic or clinical, but attempts to understand how children generally are doing, said Anita Chandra, lead author and behavioral scientist at the RAND Corp..

Previous studies on the topic have largely focused on younger children, whereas this study shed light on how preteens and teens fare emotionally, socially and academically, she said.

The study found an association between how long a parent had been deployed in the last three years and the difficulties that children faced.

It also found a link between the mental health of the nondeployed parent at home and the well-being of the child. If the parent is doing worse, the child is doing worse, pointing to the importance of also providing support to parents, Chandra said.

Read more: Family support ‘vital′ for service members being deployed

Lucille Pittard feels particularly pressured when her husband serves in leadership positions, which requires her as the spouse to help other military families at the home station. With a full-time job and two children, “it’s a heavy burden to bear,” she said.

“The main parent at home is trying to juggle so many balls that some of those balls get dropped,” she said. “I find it hard to believe that you can do it all, and so by virtue of that, since I′m the adult in the picture, sometimes I don’t have time to listen to my kids.”

Researchers analyzed data from computer-assisted telephone interviews with military children from 11 to 17 years old and nondeployed caregivers. A total of 1,507 households were screened and agreed to participate, the study said.

Some of the sources of difficulty during deployment that children mentioned were taking on more household responsibilities and missing school activities, she said.

When the parent returned home, children said it was hard to get to know him or her again, and some were worried about the next deployment. Parents’ mood changes and how their mothers and fathers were getting along were also challenges.

Jordan Pittard thinks about his father’s next potential deployment, too: “I wouldn’t say a letdown, but it would kind of hurt if he left again,” he said.

The Pittard family is fortunate, though, Lucille Pittard said, that there are two sons, about two years apart, who support each other.

“They fight like cats and dogs, but, boy, they’re best friends, too,” she said of Jordan and Taylor.

About 30 percent of the children interviewed reported symptoms of anxiety. By contrast, other research has found that 9 to 15 percent of 7- to 11-year-olds meet the criteria for an anxiety disorder in a primary care setting.

There were also some gender differences. Girls had more problems with the reintegration of a deployed parent into the family, the study found.

“A lot of the things they checked off on those questions were related to their anxiety about the parent’s next deployment, and just concerns about the emotional health of their family members,” she said. “Some people have argued that they may be more in tune with those kinds of things, being girls.”

The study points to a need to make sure that programs in place for military families are consistent with the needs of the children, she said. Targeted support for families experiencing multiple months of deployment, and for older teens and girls should be considered, she said.

The National Military Family Association, which provided funding for the study, will use the results in future programming and awareness efforts. Joyce Raezer, executive director of the organization, presented the findings at the Pentagon on Monday.

Raezer has also experienced the issues firsthand, as a wife of a retired service member and the head of an organization that consists of many military spouses.

“I can see the strain when I have an employee or a volunteer whose spouse is on their second or third deployment,” she said. “These are brave, committed, dedicated folks determined to do what they need to do, and they work very hard to hold it together, but they’re tired.”

School counselors, health care providers and religious organization leaders should all be aware of the issue so they can better direct their support, Raezer said. For example, if a mother is bringing her child into the doctor’s office with repeated stomach aches, the doctor should ask about whether the family is experiencing a deployment so as to better examine the problem.

“To have this kind of scientifically valid study that confirms a lot of what we as military spouses have been saying and noticing for a long time, it’s nice,” she said.

The data represents the interviews done in summer 2008, but researchers also followed up with the families twice since then, and will release findings on the next phase in spring 2010, Raezer said.

Despite the challenges, being in a military family has made Pittard and her sons stronger people, she said.

“Are we weary? Yes, yes we are weary. But we’re survivors and so we will survive,” she said. “We’re the type of family that says, ‘Let’s focus on the positive.’ “