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Big Storms Good At Burying Warming Gases

Tuesday, October 21st, 2008 AddThis Social Bookmark Button

The torrential rains of a single typhoon can bury tons of carbon in the ocean, two new studies suggest.

It’s Nature’s way of healing itself.

The findings help determine how much carbon that big storms have historically taken from the atmosphere and buried for thousands of years beneath the sea. And more carbon could be buried by these storms if global warming increases their intensity and frequency, as some scientists have predicted. Scientists have been looking at ways to store carbon to lower the levels of carbon dioxide building up in Earth’s atmosphere.

Scientists have long suspected that hurricanes and typhoons (along with cyclones and tropical depressions, these are all versions of storm systems called tropical cyclones) can cleanse the environment of a lot of carbon, because their rains sweep soil and plant material into rivers and then out to sea. This effect is particularly significant for mountainous islands prone to frequent hits from tropical cyclones.

Two different groups of researchers took samples of the sediment in rushing river waters on Taiwan during Typhoon Mindulle, which hit the island in July 2004. One group, whose findings are detailed in the Oct. 19 issue of the journal Nature Geoscience, took sediment samples from the LiWu River, while the other group, whose work is detailed in the June 2008 issue of the journal Geology, sampled the Chosui River.

The Nature Geoscience study, funded by The Cambridge Trusts and the UK National Environmental Research Council, found that 80 to 90 percent of the organic carbon (in the form of soil and plants) eroded by the storms around the LiWu were transported along the river to the ocean.

By dangling one-liter plastic bottles over the Chosui River during the typhoon, the researchers of the Geology study found that 61 million tons of sediment washed out to sea from the river. The amount of carbon contained in that sediment is about 95 percent as much as the river transports during normal rains over the entire year. That works out to more than 400 tons of carbon washing away during the storm for each square mile of the watershed, the researchers reported. Their work was funded by the U.S. National Science Foundation.

The carbon in the soil and plants came from carbon dioxide from the atmosphere. When the storm washes the sediment out to sea, it can sink down to the deep ocean, where it will eventually compact and form rocks that can store that carbon for millions of years.

And if typhoons and hurricanes do become more intense or frequent, as some models have indicated, the burial of carbon in the ocean from storm runoff could counteract some part of the warming, by locking the carbon away in the deep ocean, the researchers of the Nature Geoscience study said.

But typhoon runoff is not a cure-all for the carbon dioxide that’s been building up in the Earth’s atmosphere. Not enough carbon is washed down either as plant material and soil or by chemical weathering of rocks (where carbon dioxide and water disintegrate rock) to get rid of all the extra carbon dioxide that has built up in the atmosphere.

“You’d have to weather [and erode] all the volcanic rocks in the world to reduce the CO2 back to pre-industrial times,” said Anne Carey of Ohio State University and a member of the Geology study team.

Understanding how typhoon runoff fits into the Earth’s carbon cycle could help sharpen climate change models, though.

Source — MSNBC

More Alzheimer’s Risk For Hispanics, Studies Suggest

Tuesday, October 21st, 2008 AddThis Social Bookmark Button

PHILADELPHIA — Antonio Vasquez was just 60 when Alzheimer’s disease derailed him.

He lost his job at a Queens bakery because he kept burning chocolate chip cookies, forgetting he had put them in the oven. Then he got lost going to job interviews, walking his neighborhood in circles.

Teresa Mojica of Philadelphia was 59 when she got Alzheimer’s, making her so argumentative and delusional that she sometimes hits her husband. And Ida J. Lawrence was 57 when she started misplacing things and making mistakes in her Boston dental school job.

Besides being young Alzheimer’s patients — most Americans who develop it are at least 65, and it becomes more common among people in their 70s or 80s — the three are Hispanic, a group that Alzheimer’s doctors are increasingly concerned about, and not just because it is the country’s largest, fastest-growing minority.

Studies suggest that many Hispanics may have more risk factors for developing dementia than other groups, and a significant number appear to be getting Alzheimer’s earlier. And surveys indicate that Latinos, less likely to see doctors because of financial and language barriers, more often mistake dementia symptoms for normal aging, delaying diagnosis.

“This is the tip of the iceberg of a huge public health challenge,” said Yanira L. Cruz, president of the National Hispanic Council on Aging. “We really need to do more research in this population to really understand why is it that we’re developing these conditions much earlier.”

It is not that Hispanics are more genetically predisposed to Alzheimer’s, say experts, who say the diversity of ethnicities that make up Hispanics or Latinos make a genetic explanation unlikely.

Rather, experts say several factors, many linked to low income or cultural dislocation, may put Hispanics at greater risk for dementia, including higher rates of diabetes, obesity, cardiovascular disease, stroke and possibly hypertension.

Less education may make Hispanic immigrants more vulnerable to those medical conditions and to dementia because scientists say education may increase the brain’s plasticity or ability to compensate for symptoms. And some researchers cite as risk factors stress from financial hardship or cultural adjustment.

The Alzheimer’s Association says that about 200,000 Latinos in the United States have Alzheimer’s, but that, by 2050, based on Census Bureau figures and a study of Alzheimer’s prevalence, the number could reach 1.3 million. (It predicts that the general population of Alzheimer’s patients will grow to 16 million by 2050, from 5 million now.)

“We are concerned that the Latino population may have the highest amount of risk factors and prevalence, in comparison to the other cultures,” said Maria Carrillo, the group’s director of medical and scientific relations.

In response, Alzheimer’s and Hispanic organizations have started health fairs and support groups. Some Alzheimer’s centers have opened clinics in Latino neighborhoods.

“There’s some taboos” about Alzheimer’s, said Liany Arroyo, director of the Institute for Hispanic Health at the National Council of La Raza, which surveyed Latinos. “Folks did not necessarily understand what it was.”

Antonia Lopez, who immigrated from Panama to Boston, showed symptoms at about 60, but it was 10 years before the family acknowledged it was Alzheimer’s, said her daughter, Carol Franklin.

“My mom was telling people, in her confusion, that I spanked her,” she said. “My brother believed that. He said to me at one point, ‘Don’t say that my mom has Alzheimer’s, because I believe it’s just part of being old.’ ”

Overwhelmingly, Hispanics with Alzheimer’s live with multigenerational families instead of in nursing homes. That support can be beneficial, experts say, but it severely stresses families.

When Maria Contreras, a Salvadoran immigrant, began wandering and hallucinating, her daughter, Teresa Navas, took her into her home in Silver Spring, Md. The strain on Ms. Navas and her children compelled her to place her mother in a nursing home, but when she kept getting sick, Ms. Navas took her home again and quit her job teaching Spanish.

“I have to be with her all the time,” she said. “Sometimes she doesn’t even know who I am.”

Mr. Vasquez’s daughter, Ana, 39, moved her parents to her Philadelphia home. She works at a neighborhood grocery and tells her sons, 6 and 11, “Watch out for your grandfather.”

Once, Mr. Vasquez was found hitchhiking on a major Philadelphia street. On a visit to the Bronx neighborhood where he had lived, he wandered away, leaving his family frenetically searching subway stations. “I was desperate, crying, especially when the night was coming,” said his wife, also named Ana.

Nine hours later, he appeared on their Philadelphia porch, having happened upon a bus to Philadelphia and given the driver a card with their address.

Scientists are searching for what sets Latinos apart. Dr. Rafael A. Lantigua, a professor of clinical medicine at Columbia University Medical School, said, “There’s no gene at this point that we can say this is just for Latinos.” Dr. Lantigua added that one gene that increased Alzheimer’s risk was less prevalent in Latinos than non-Hispanic whites.

Kala M. Mehta, an assistant professor in the geriatrics division at the University of California, San Francisco, analyzed autopsies from 3,000 Alzheimer’s patients, finding “similar neuropathology” among Latinos, whites and African-Americans.

And Mary Sano, director of the Alzheimer’s Disease Research Center at the Mount Sinai School of Medicine, found that different ethnic groups shared the most common behavioral symptoms, like repeating sentences and uncooperativeness.

But researchers say they have seen disparities in the timing of the illness and its severity when diagnosed.

Dr. Steven E. Arnold, director of the Penn Memory Center at the University of Pennsylvania, studied 2,000 white, African-American and Latino Alzheimer’s patients.

Dr. Arnold found that the Latinos, mostly low-income, poorly educated Puerto Ricans, many with diabetes, “have more depression,” and their scores on tests in Spanish measuring dementia averaged about 15 percent lower than African-Americans and about 30 percent lower than non-Hispanic whites. Latinos were on average about three-and-a-half years younger than non-Hispanic whites and about five years younger than African-Americans, he said.

Dr. Christopher M. Clark, director of the Center of Excellence for Research on Neurodegenerative Diseases at the University of Pennsylvania, studied the age at which 174 Alzheimer’s patients in California, New York and Pennsylvania first showed symptoms and found Spanish speakers were on average 6.8 years younger (about 67) than non-Hispanic whites, regardless of whether they were Mexican, Caribbean or South American. That Latinos are on average younger than other Americans accounted for a small part of the gap, but not most of it, Dr. Clark said.

Research is scant on the age of onset in Latinos remaining in their native homes, but Dr. Clark said patients in two clinics in Mexico and Puerto Rico did not show symptoms early.

Mary N. Haan, a University of Michigan epidemiologist heading the Sacramento Area Latino Study on Aging, studied 1,800 Mexican-Americans over 10 years and found greater likelihood of Alzheimer’s for those more “acculturated” to American society, based on a number of factors, including diet and social networks. Dr. Haan attributed that to higher stress from being “relatively poorer off” and “more socially isolated.”

Dr. Cruz, of the National Hispanic Council on Aging, said, “As you acculturate, you lose those protective factors linked to nutrition, physical activity, social support system, that come with you when you first arrive here.”

Dr. Haan found more acculturated people more prone to diabetes, and people with diabetes or obesity more likely to have Alzheimer’s. Researchers theorize that high insulin levels and poor cerebral blood flow can cause brain changes that accompany Alzheimer’s, said Dr. Jose A. Luchsinger, associate professor of medicine and epidemiology at Columbia University Medical Center.

Dr. Cruz said many Alzheimer’s risk factors “have to do with poor education,” which aggravates nutrition, financial status and health care.

Mrs. Mojica, from Puerto Rico, with five years of schooling, developed diabetes and hypertension after a hard life in a rundown row house, where she and her husband care for their 39-year-old mentally retarded son.

Not all Hispanics have medical or sociological risk factors.

Ida Lawrence, whose Alzheimer’s has made her hide money in socks and shower obsessively, attended high school in Honduras, learning English. Her husband, Robert, said he thought her dementia might be inherited, adding, “She’s been healthy except for the fact that she was coming down with this Alzheimer’s thing.”

Mr. Lawrence, who has prostate cancer, struggles to care for his wife, still only 63. “Everybody says to me, ‘Bob it’s going to get worse,’ ” he said.

Ms. Franklin finally moved her mother, Ms. Lopez, to a nursing home, where she cries and “doesn’t want nobody to touch her,” she said.

“It hurts me so much to see her like that,” Ms. Franklin said. “It’s like I can see her on one side of the mountain and say, that’s not my mom.”

Source — The New York Times