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A Canadian researcher has discovered that sound travels (21) air more than one-half kilometer an hour slower than had been believed. The discovery has surprised many engineers and scientists who learned they had been (22) the wrong speed of sound for many years.The speed of sound in air had been (23) to be three-hundred-thirty-one-point-two-nine meters a second. But Doctor George Wong found, (24) accident, that the speed of sound is only three-hundred-thirty-one-point-one-three meters a second. That is a difference of about sixteen centimeters a second.Doctor Wong is a member of the National Research Council of Canada. He was studying ways to (25) exactly the sound created by microphones. One of his experiments (26) a number he could use to find the speed of sound. He was (27) to learn that the speed of sound was slower than scientists had thought.To explain the difference, Doctor Wong spent eighteen months (28) past test research on the speed of sound. He finally found the (29) of the difference. It was a mathematics mistake (30) in Nineteen-Forty-Two by physicist H-C Hardy.Doctor Wong’s (31) does not mean a big change for the science of sound. This is (32) Doctor Hardy and Doctor Wong measured the speed of sound for what is called" standard air".Standard air exists only (33) thought. It is a way for scientists to agree (34) the same speed of sound. (35) the air around us, standard air always has a temperature of zero degrees Celsius and the same atmospheric pressure (36) the air at sea level. Standard air always has same amounts of nitrogen, oxygen, carbon dioxide and (37) gases. And in standard air, the speed of sound does not change.The change in the new speed of sound is (38) small to affect the work of most sound scientists and engineers. But scientists say Doctor Wong’s discovery may (39) improve instruments (40) use the speed of sound to measure very short distances. 33().
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A3型题男，21岁，淋雨后突发寒战、高热、全身酸痛，次日出现右侧胸痛、咳嗽、咳痰，X线胸片示右上肺大片实变。既往体健。 最可能的诊断为（）
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A new report by the U.N. AIDS organizations finds the global AIDS epidemic is worsening. The agency says more people in all regions around the world are becoming infected with HIV, the virus which causes AIDS. UNAIDS reports significant progress has been made in providing treatment for larger numbers of AIDS victims and in achieving greater political and financial commitments in the fight against the fatal disease. Despite this, the report says none of these efforts has been enough to prevent the spread of HIV/AIDS.Last year, the report notes five million people became newly infected with HIV. That is more people than any previous year. Currently, it says, more than 38 million people are living with the disease. UNAIDS Senior Adviser Karen Stanecki. says Asia, with 60 percent of the world’s population, is home to some of the fastest-growing epidemics in the world. In 2003 alone, she says, more than one million people became infected with HIV."Equally alarming, we have only just begun to witness the full impact of AIDS on African societies as infections continue to grow and people are dying in large numbers," said Ms. Stanecki. "The scale of the problem in Africa is well-documented, with over 25-million infections. If we do not act now,60 percent of today’s 15 year olds will not reach their 60th birthday."The report says the Caribbean is the hardest hit region in the world after Africa. It also finds the HIV/AIDS epidemic is continuing to expand in Eastern Europe and Central Asia, mainly due to intravenous drug users.UNAIDS says infections also are on the rise in the United States and Western Europe. It blames this largely on the widespread availability of anti-AIDS drugs, which it says has made some people in these wealthy countries complacent. UNAIDS Director of Monitoring and Evaluation, Paul De Lay, acknowledges that around the world prevention programs are reaching fewer than one in five people who need them. Nevertheless ,he says there has been a dramatic increase in prevention activities for young people and several other successes as well."In Africa, for instance ,60 percent of children have access to AIDS education both in primary and secondary schools, "said Mr. De Lay. "That is a huge increase from the late 1990’s. In highly vulnerable groups like sex workers, we are seeing a real success story in Africa. Thirty-two percent of sex workers who are identified have access to HIV prevention and there is a large increase in condom use in this population."The report says global spending on AIDS has increased greatly, but, more is needed. It estimates $12 billion will be needed by next year, and $ 20 billion by 2007, for prevention and care in developing countries. The United Nations says AIDS funding has increased sharply in recent years, in part due to the U.S. government’s global AIDS initiative. But it says still, globally less than half the money needed is being provided. According to UNAIDS Senior Adviser Karen Stanecki,().
A Canadian researcher has discovered that sound travels (21) air more than one-half kilometer an hour slower than had been believed. The discovery has surprised many engineers and scientists who learned they had been (22) the wrong speed of sound for many years.The speed of sound in air had been (23) to be three-hundred-thirty-one-point-two-nine meters a second. But Doctor George Wong found, (24) accident, that the speed of sound is only three-hundred-thirty-one-point-one-three meters a second. That is a difference of about sixteen centimeters a second.Doctor Wong is a member of the National Research Council of Canada. He was studying ways to (25) exactly the sound created by microphones. One of his experiments (26) a number he could use to find the speed of sound. He was (27) to learn that the speed of sound was slower than scientists had thought.To explain the difference, Doctor Wong spent eighteen months (28) past test research on the speed of sound. He finally found the (29) of the difference. It was a mathematics mistake (30) in Nineteen-Forty-Two by physicist H-C Hardy.Doctor Wong’s (31) does not mean a big change for the science of sound. This is (32) Doctor Hardy and Doctor Wong measured the speed of sound for what is called" standard air".Standard air exists only (33) thought. It is a way for scientists to agree (34) the same speed of sound. (35) the air around us, standard air always has a temperature of zero degrees Celsius and the same atmospheric pressure (36) the air at sea level. Standard air always has same amounts of nitrogen, oxygen, carbon dioxide and (37) gases. And in standard air, the speed of sound does not change.The change in the new speed of sound is (38) small to affect the work of most sound scientists and engineers. But scientists say Doctor Wong’s discovery may (39) improve instruments (40) use the speed of sound to measure very short distances. 29().
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