新城子到沈阳肤康皮肤病医院做什么车(沈阳市带状疱诊皮肤病医院) (今日更新中)

LOS ANGELES, June 17 (Xinhua) -- The size of low-oxygen zones created by respiring bacteria is extremely sensitive to changes in depth caused by oscillations in climate, thus posing a distant threat to marine life, a new study suggests."The growth of low-oxygen regions is cause for concern because of the detrimental effects on marine populations -- entire ecosystems can die off when marine life cannot escape the low- oxygen water," said lead researcher Curtis Deutsch, assistant professor of atmospheric and oceanic sciences at University of California, Los Angeles."There are widespread areas of the ocean where marine life has had to flee or develop very peculiar adaptations to survive in low- oxygen conditions," Deutsch said in the study to be published in an upcoming print edition of the journal Science.A team led byDeutsch used a specialized computer simulation to demonstrate for the first time that fluctuations in climate can drastically affect the habitability of marine ecosystems.The study also showed that in addition to consuming oxygen, marine bacteria are causing the depletion of nitrogen, an essential nutrient necessary for the survival of most types of algae."We found there is a mechanism that connects climate and its effect on oxygen to the removal of nitrogen from the ocean," Deutsch said. "Our climate acts to change the total amount of nutrients in the ocean over the timescale of decades."Low-oxygen zones are created by bacteria living in the deeper layers of the ocean that consume oxygen by feeding on dead algae that settle from the surface. Just as mountain climbers might feel adverse effects at high altitudes from a lack of air, marine animals that require oxygen to breathe find it difficult or impossible to live in these oxygen-depleted environments, Deutsch said.Sea surface temperatures vary over the course of decades through a climate pattern called the Pacific Decadal Oscillation, during which small changes in depth occur for existing low-oxygen regions, Deutsch said. Low-oxygen regions that rise to warmer, shallower waters expand as bacteria become more active; regions that sink to colder, deeper waters shrink as the bacteria become more sluggish, as if placed in a refrigerator."We have shown for the first time that these low-oxygen regions are intrinsically very sensitive to small changes in climate," Deutsch said in remarks published Friday by the American Association for the Advancement of Science on its website. "That is what makes the growth and shrinkage of these low-oxygen regions so dramatic."Molecular oxygen from the atmosphere dissolves in sea water at the surface and is transported to deeper levels by ocean circulation currents, where it is consumed by bacteria, Deutsch said."The oxygen consumed by bacteria within the deeper layers of the ocean is replaced by water circulating through the ocean," he said. "The water is constantly stirring itself up, allowing the deeper parts to occasionally take a breath from the atmosphere."A lack of oxygen is not the only thing fish and other marine life must contend with, according to Deutsch. When oxygen is very low, the bacteria will begin to consume nitrogen, one of the most important nutrients that sustain marine life."Almost all algae, the very base of the food chain, use nitrogen to stay alive," Deutsch said. "As these low-oxygen regions expand and contract, the amount of nutrients available to keep the algae alive at the surface of the ocean goes up and down. "Understanding the causes of oxygen and nitrogen depletion in the ocean is important for determining the effect on fisheries and fish populations, he said.

XICHANG, Sichuan, Aug. 12 (Xinhua) -- China launched a communications satellite PAKSAT-1R for Pakistan at 0:15 a.m. Friday from the Xichang Satellite Launch Center in southwest China's Sichuan Province.The satellite was carried by a Long March-3B carrier rocket, according to the launch center. It is China's first in-orbit delivery to Asian customers and also the first commercial satellite export to international users this year.According to statistics from the control center, the satellite successfully separated from its carrier rocket and entered geostationary transfer orbit as scheduled, 26 minutes after being launched.PAKSAT-1R will provide a range of services, including broadband Internet, telecom and broadcasting, covering some regions of Europe, South Asia, the Middle East, and the eastern Africa.The contract for the PAKSAT-1R was signed in 2008 between China Great Wall Industry Corporation and the Space and Upper Atmosphere Research Commission of Pakistan.China and Pakistan share a long history of space technology cooperation. Pakistan's first low-orbit satellite, BADR-A, was launched by China in 1990 with Long March 2E rocket.

WASHINGTON, July 5 (Xinhua) -- Intake of high levels of folate, a water-soluble B vitamin that occurs naturally in food, may reduce colorectal cancer risk, according to a new study published Tuesday in Gastroenterology, the official journal of the American Gastroenterological Association (AGA) Institute. "We found that all forms and sources of folate were associated with lower risk of colorectal cancer," said lead author Victoria Stevens, of the American Cancer Society. "The strongest association was with total folate, which suggests that total folate intake is the best measure to define exposure to this nutrient because it encompasses all forms and sources."Total folate includes naturally occurring food folate and folic acid from fortified foods and dietary supplements.The research team investigated the association between folate intake and colorectal cancer among 99,523 participants in the Cancer Prevention Study II Nutrition Cohort; a total of 1,023 participants were diagnosed with colorectal cancer between 1999 and 2007, a period entirely after folate fortification began. Neither higher nor lower risk was observed during the first two years of follow-up (1999 to 2001), while associations were statistically significantly inverse for the subsequent years (2002 to 2007). The findings of this study add to the epidemiologic evidence that high folate intake reduces colorectal cancer incidence.Folates are essential nutrients needed to make components used for functions required for normal cell growth, including DNA synthesis and repair. Because these processes are critical for cell growth and differentiation, the relationship between folate intake and cancer development has been investigated in several cancers, and most extensively in colorectal cancer.

BEIJING, Aug. 3 (Xinhuanet) -- NASA Tuesday confirmed a 4-foot in diameter sphere debris as a fuel tank that was part of the space shuttle Columbia's electrical power system,according to U.S. news reports.NASA engineers identified the 4-foot piece of spherical debris as one of the18 tanks that held chilled oxygen and hydrogen used by the shuttle's electricity-generating fuel cells.This Aug. 1, 2011 handout photo provided by the Nacogdoches Police Department shows a 4-feet in diameter sphere found in Lake Nacogdoches, Texas on Monday, Aug. 1. Police say low water levels at the lake during the drought have led to recovery of a container-like object that could be from space shuttle Columbia. The shuttle broke apart and burned in February 2003, scattering remnants over East TexasPolice in the city of Nacogdoches, about 160 miles northeast of Houston, said Monday the low water levels of Lake Nacogdoches during the record drought revealed an unexpected object that could be from space shuttle Columbia. The shuttle broke apart and burned as it re-entered the atmosphere on February 1, 2003.The tank will be moved to the Kennedy Space Center, where the rest of the Columbia is stored. Approximately 40 percent of the spacecraft has been recovered.

SAN FRANCISCO, July 14 (Xinhua) -- Microsoft on Thursday introduces a hacking alert system to its Windows Live Hotmail email service alongside banning common passwords."When someone's account gets hijacked, their friends often find out before they do, because the hijacker uses their account to send spam or phishing email to all their contacts," said Microsoft in a blog post.The new security feature adds a "My friend's been hacked!" option in the "mark as" menu in Hotmail and also enables users to report hacked accounts via the junk mail filing screen.Then an alert will be sent to Microsoft, which will "make sure the account can no longer be used by spammers and activates an account recovery process to allow the owner to take back control the accounts."Users can report any email account as compromised and Hotmail will provide the information to other email providers like Yahoo! and Gmail, said the blog.Meanwhile, Microsoft said Hotmail will roll out a feature to prevent users from choosing commonly used and weak passwords, such as "123456," "ilovecats" and "gogiants." Users who currently use a weak password will be asked to change to a stronger one in the future.Hotmail, first launched in July 1996, is one of the first free email providers, and was acquired by Microsoft in 1997 for an estimated 400 million U.S. dollars.According to statistics released by comScore last August, Hotmail was then the world's largest web-based email service with around 364 million users, followed by Yahoo! Mail (280 million) and Gmail (191 million).

来源：资阳报