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WASHINGTON, Aug. 17 (Xinhua) -- Latest research shows that the Moon could be younger than previous estimates. The findings were published online Wednesday in the Nature journal.The prevailing theory of the Moon's origin is that it was created by a giant impact between a large planet-like object and the proto-Earth. The energy of this impact was sufficiently high that the Moon formed from melted material that was ejected into space. As the Moon cooled, this magma solidified into different mineral components. Analysis of lunar rock samples thought to have been derived from the original magma has given scientists a new estimate of the Moon's age.According to this theory for lunar formation, a rock type called ferroan anorthosite, or FAN, is the oldest of the Moon's crustal rocks, but scientists have had difficulty dating FAN samples. The research team used newly refined techniques to determine the age of a sample of FAN from the lunar rock that was brought back to Earth by the Apollo 16 mission in 1972.The team analyzed the isotopes of the elements lead and neodymium to place the FAN sample's age at 4.36 billion years. This figure is significantly younger than earlier estimates of the Moon's age that range as old as the age of the solar system at 4. 568 billion years. The new, younger age obtained for the oldest lunar crust is similar to ages obtained for the oldest terrestrial minerals -- zircons from western Australia -- suggesting that the oldest crusts on both Earth and Moon formed at approximately the same time, and that this time dates from shortly after the giant impact.This study is the first in which a single sample of FAN yielded consistent ages from multiple isotope dating techniques. This result strongly suggests that these ages pinpoint the time at which the sample crystallized."The extraordinarily young age of this lunar sample either means that the Moon solidified significantly later than previous estimates, or that we need to change our entire understanding of the Moon's geochemical history," Carnegie Institute of Science's geochemist and study author Richard Carlson said.

WASHINGTON, Sept. 26 (Xinhua) -- Older people with low blood levels of vitamin B12 markers may be more likely to have lower brain volumes and have problems with their thinking skills, according to researchers at Rush University Medical Center in Chicago.The results of the study will be published Tuesday in Neurology, the medical journal of the American Academy of Neurology.Foods that come from animals, including fish, meat, especially liver, milk, eggs and poultry are usual sources of vitamin B12.The study involved 121 older residents of the south side of Chicago over the age of 65. They had blood drawn to measure levels of vitamin B12 and B12-related markers that can indicate a B12 deficiency. The same subjects took tests measuring their memory and other cognitive skills.An average of four-and-a-half years later, MRI scans of the participants' brains were taken to measure total brain volume and look for other signs of brain damage.Having high levels of four of five markers for vitamin B12 deficiency was associated with having lower scores on the cognitive tests and smaller total brain volume."Our findings definitely deserve further examination," said Christine Tangney, associate professor at Rush University Medical Center and lead author of the study. "It's too early to say whether increasing vitamin B12 levels in older people through diet or supplements could prevent these problems, but it is an interesting question to explore. Findings from a British trial with B vitamin supplementation are also supportive of these outcomes."On the cognitive tests, the scores ranged from -2.18 to 1.42, with an average of 0.23. For each increase of one micromole per liter of homocysteine -- one of the markers of B12 deficiency -- the cognitive scores decreased by 0.03 standardized units or points.Tangney noted that the level of vitamin B12 itself in the blood was not associated with cognitive problems or loss in brain volume. "Our findings lend support for the contention that poor vitamin B12 status is a potential risk factor for brain atrophy and may contribute to cognitive impairment," said Tangney.

BEIJING, Sept. 14 (Xinhuanet) -- Scientists had discovered the fossils of a new species of ancient carnivorous fish, National Geographic reported Monday.The newly-found ancient fish, "Laccognathus embryi", is a 1.8-meter-long predator, which was "waiting to lunge out to grab whatever was in front of it," said study co-author Ted Daeschler, a vertebrate zoologist at the Academy of Natural Sciences in Philadelphia, the U.S..It had a jaw filled with sharp teeth that were 1.5 inches long, the Journal of Vertebrate Paleontology described.The fish lived in the Devonian period, 415 to 360 million years ago, which "was a fish-eats-fish kind of world," Daeschler said. "There was a real arms race going. If you didn't have good armor on your body, you were very vulnerable.""It's not just finding the animal - it's also placing the animal in its evolutionary crucible," Daeschler added.Its closest living relative is the lungfish which can survive in the drought, scientists said.Scientists hope the finding can help in their study on the revolution of fishes as well as other species.

WASHINGTON, Aug. 3 (Xinhua) -- The annual number of new HIV infections in the United States was relatively stable at approximately 50,000 new infections each year between 2006 and 2009, the Centers for Disease Control and Prevention's first multi- year estimates from its national HIV incidence surveillance find.However, HIV infections increased among young men who have sex with men (MSM) between 2006 and 2009, driven by alarming increases among young, black MSM -- the only subpopulation to experience a sustained increase during the period.According to the new estimates, there were 48,600 new HIV infections in the United States in 2006, 56,000 in 2007, 47,800 in 2008 and 48,100 in 2009. The multi-year incidence estimates allow for a reliable examination of trends over time. They reveal no statistically significant change in HIV incidence overall from 2006 to 2009, with an average of 50,000 for the four-year period. In 2009, the largest number of new infections was among white MSM (11,400), followed closely by black MSM (10,800). Hispanic MSM (6, 000) and black women (5,400) were also heavily affected.The new estimates were published Wednesday in the on-line scientific journal PLoS ONE."More than 30 years into the HIV epidemic, about 50,000 people in this country still become infected each year. Not only do men who have sex with men continue to account for most new infections, young gay and bisexual men are the only group in which infections are increasing, and this increase is particularly concerning among young African American MSM," said CDC Director Thomas Frieden. " HIV infections can be prevented. By getting tested, reducing risky behaviors, and getting treatment, people can protect themselves and their loved ones."

WASHINGTON, Aug. 2 (Xinhua) -- Breastfeeding protects against childhood obesity, but less than 4 percent of U.S. hospitals provide the full range of support mothers need for breastfeeding, according to a report issued by the Centers for Disease Control and Prevention Tuesday.Improving rates of breastfeeding by providing better hospital support to mothers and babies is an important strategy to improve children's health, including a reduced risk of childhood obesity, the monthly Vital Signs report said."Hospitals play a vital role in supporting a mother to be able to breastfeed," it said."Those first few hours and days that a mom and her baby spend learning to breastfeed are critical. Hospitals need to better support breastfeeding, as this is one of the most important things a mother can do for her newborn. Breastfeeding helps babies grow up healthy and reduces health care costs," it added.The report found only 14 percent of hospitals have a written and model breastfeeding policy.It also found in nearly 80 percent of hospitals, healthy breastfeeding infants are given formula when it is not medically necessary, a practice that makes it much harder for mothers and babies to learn how to breastfeed and continue breastfeeding at home.Additionally, only one-third of hospitals practise rooming in, which helps mothers and babies learn to breastfeed by allowing frequent chances to breastfeed.Finally, the report found in nearly 75 percent of hospitals, mothers and babies don't get the support they need when they leave hospitals, including a follow-up visit, a phone call from hospital staff and referrals to lactation consultants, and other important support systems in their communities.