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WASHINGTON, July 7 (Xinhua) -- Space shuttle Atlantis will soar into the sky Friday on NASA's 135th and final flight. Its scheduled return to Earth later this month will mark the end of NASA's 30-year space program.Since its onset with the launch of space shuttle Columbia, the program has been seen as a cheap, safe and reliable way for space exploration.Despite its great contributions to U.S. manned space flight, it has also left some grave and tragic lessons, making its termination inevitable.HIKING COSTSLaunched in 1972 by then President Richard Nixon, the shuttle program aimed to provide a new system of affordable space travel and proved to be NASA's most enduring project in its 50 years of existence.In 1981, shuttle Columbia made its first shuttle flight for two days. It was the ultimate hybrid and the first reusable spacecraft.Launched like a rocket and gliding back to Earth like an airplane, space shuttles not only can act as a space taxi to carry astronauts, but have the muscle of a long-distance trucker to haul heavy machinery.The spaceship boasts more than 3,500 subsystems and 2.5 million parts and is nine times faster than a speeding bullet as it climbs heavenward. That versatility, however, has translated into higher costs.NASA originally estimated the program would cost about 90 billion U.S. dollars. However, its actual cost stands at about 200 billion dollars, compared with the 151 billion dollars spent on Apollo which took Americans to the moon in 1969.In an article in Technology Review, John Logsdon, former head of the Space Policy Institute at George Washington University, drew a direct connection between the ravenous shuttle budget and the lack of other large advances in manned space flight."By operating the system for 30 years, with its high costs and high risk, rather than replacing it with a less expensive, less risky second-generation system, NASA compounded the original mistake of developing the most ambitious version of the vehicle," he wrote."The shuttle's cost has been an obstacle to NASA starting other major projects," he added.HIGH RISKIn terms of safety, the shuttles have never been as reliable as their designers had envisioned.On average, one out of every 67 flights ended up with fatal accidents. Based on the rate of deaths per million miles traveled, the space shuttle is 138 times riskier than a passenger jet.Seven astronauts onboard died when Challenger exploded about a minute after launch in 1986. Nearly two decades after the tragic blast, a new catastrophe descended when the shuttle Columbia disintegrated moments before landing in 2003, killing another seven spacemen.Again, the shuttle program was shelved for more than two years as NASA stepped up efforts to make it safer. But experts say the fundamental problem related to shuttles' safety cannot be solved due to their "birth defects.""It is in the nation's interest to replace the Shuttle as soon as possible," concluded the panel that investigated the 2003 Columbia accident.

WASHINGTON, July 5 (Xinhua) -- Adhering to a healthy lifestyle, including not smoking, exercising regularly, having a low body weight and eating a healthy diet, appears to lower the risk of sudden cardiac death (SCD) in women, according to a study to be published Wednesday in the Journal of the American Medical Association."Sudden cardiac death (defined as death occurring within one hour after symptom onset without evidence of circulatory collapse) accounts for more than half of all cardiac deaths, with an incidence of approximately 250,000 to 310,000 cases annually in the United States," the authors write as background information in the study.Using data collected as part of the Nurses' Health Study, Stephanie Chiuve, of Brigham and Women's Hospital and Harvard Medical School, and colleagues examined the association between a healthy lifestyle and risk of SCD.A total of 81,722 women who participated in the Nurses' Health Study from June 1984 to June 2010 were included in the new study, and lifestyle factors were assessed via questionnaires every two to four years. A low-risk lifestyle was defined as not smoking, having a body mass index (BMI) of less than 25, exercise duration of 30 minutes/day or longer, and consuming a diet closely related to a Mediterranean-style diet (emphasizes high intake of vegetables, fruits, nuts, legumes, whole grains and fish, with moderate alcohol intake).During the 26 years of follow-up, there were 321 cases of SCD among women (average age 72 years at the time of the SCD event) in the study. All four low-risk factors were significantly and independently associated with a lower risk of SCD. Not smoking, exercising and eating a healthy diet each were inversely associated with risk of SCD. BMI also was associated with the risk of SCD, with women having a BMI between 21 and 24.9 at lowest risk.Women at low risk for all four lifestyle factors had a 92 percent lower risk of SCD when compared with women at low risk for none of the four lifestyle factors."In this cohort of female nurses, adherence to an overall healthy lifestyle was associated with a lower risk of SCD and may be an effective strategy for the prevention of SCD," the authors write.

CANBERRA, Sept. 24 (Xinhua) -- Australian scientists on Saturday said a satellite due to re-enter Earth poses a negligible threat to life and property on Earth.U.S. National Aeronautics and Space Administration's Upper Atmosphere Research Satellite (UARS), which weighs more than five tons, is expected to re-enter the Earth's atmosphere at 1058 (AEST) on Saturday. The U.S.-based Center for Orbital and Re-entry Debris Studies estimates that re-entry could occur up to seven hours before or after this time.According to Nonathan Nally, a former editor of two space magazines and currently editor of the Australian Space News website, the satellite poses a negligible threat to life and property on Earth."Most of the satellite will burn up on re-entry, with perhaps as many as 26 stronger or harder small pieces surviving to reach the surface," Nally said in a statement."But with the majority of the Earth comprising oceans or uninhabited (or very sparsely populated) remote regions, the chances are overwhelming that any pieces of UARS that survive re- entry will fall harmlessly and never be seen again."Since the spacecraft is no longer powered, U.S. National Aeronautics and Space Administration has no control over where it comes down, but Nally said there is a small chance that debris from the satellite could land in Australia.Debris from SkyLab, another satellite which plunged to Earth, was scattered over parts of Western Australia in 1979. Skylab weighed about 77 tonnes, many times more than the UARS.?Dr Alice Gorman, a lecturer in the Department of Archaeology, specializing in space archaeology, at Flinders University in South Australia, said the UARS satellite re-entry is very reminiscent of Skylab in 1979."There is the same exaggeration of the hazard through the media, public anxiety as the advance warning allows for speculation, and a lack of understanding of what the risks actually are," he said in a statement."Should it land in Australia, we might expect the same rush for souvenirs as we saw with Skylab, as anything that has been in space has a special meaning on Earth."?UARS was launched on 12 September 1991 and decommissioned on 15 December 2005. Its total dry mass is about 5.5 tonnes. UARS is one of the largest NASA satellites to plunge back to Earth uncontrolled in the last 30 years.Since the beginning of the Space Age in the late-1950s, there have been no confirmed reports of an injury resulting from re- entering space objects.? Nor is there a record of significant property damage resulting from a satellite re-entry.

KATSINA, Nigeria May 31 (Xinhua) -- At least 10 secondary school teachers are reported to have died of food poisoning, and several others hospitalized in northern Nigeria's Katsina State, the News Agency of Nigeria reported on Tuesday.The incident occurred at the weekend at a workshop organiZed by the state Ministry of Education for some 650 teachers at Government Day Secondary School (GDSS), Kofar Yan'daka, Katsina.The report said soon after taking their lunch, supplied by a popular corporate caterer on the fateful day, some of the teachers were vomiting and afflicted by diarrhoea, as a result of which they were rushed to the Federal Medical Center, Katsina and the Police Clinic for medication.Ten of the affected teachers were said to have died as a result of the infection.State police spokesperson Abubakar Ibrahim confirmed the incident to reporters.He said only one teacher died, while 19 others were hospitalized.He said 12 of the affected teachers had already been discharged from the hospitals, while seven others were still on admission at the Federal Medical Center and Katsina Police Clinic.He said the police had already collected sample of the food supplied by the caterer for clinical analysis.

BEIJING, Aug. 16 (Xinhuanet) -- It is widely accepted that obesity leads to an increased risk of health complications, but new studies quoted by media Tuesday challenge the conventional notion.“Our studies challenge the idea that all obese individuals need to lose weight,” said Dr. Jennifer Kuk, assistant professor in York University’s School of Kinesiology & Health Science in Toronto.  One of the studies used data from the Aerobics Center Longitudinal Study consisting of 29,533 individuals and assessed their mortality in 16 years.It found no difference in death risks between normal-weight individuals and obese ones. "Since the obese people did not have greater risk of dying than normal weight individuals, they don’t need to lose weight," said Dr. Kuk.But the finding did not give obese individuals a “free license” to gain weight, Dr. Kuk added. Maintaining weight, eating right and exercising may be better than trying to lose weight in the long run, said Dr. Kuk.