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A3/A4型题青年男性，2d来胸背部疼痛，今晨出现双下肢无力，伴两便障碍，查脐以下各种感觉障碍，双下肢肌力0级，无病理反射。 最可能的诊断是（）.
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TEXT E Seven years ago, an Environmental Protection Agency statistician stunned researchers studying the effects of air pollution on health when he reported analyses indicating that as many as 60, 000 U. S. residents die each year from breathing federally allowed concentrations of airborne dust. This and subsequent studies figured prominently in EPA’s decision last year to ratchet down the permitted concentration of breathable particles in urban air -- and in human airways. At the time, many industrialists argued that they shouldn’t have to pay for better pollution control because science had yet to suggest a plausible biological mechanism by which breathing low concentrations of urban dust might sicken or kill people. Now, scientists at the University of Texas Houston Health Science Center describe how they uncovered what they think may be one of the basic elements of that toxicity. On the alert for foreign debris, a community of white blood cells known as alveolar macrophages patrols small airways of the lung. When these cells encounter suspicious material, they identify it and send out a chemical clarion call to rally the immune system cells best suited to disabling and disposing of such matter. The trick is to recruit only as many troops as are needed. If they call in too many, the lung can sustain inflammatory damage from friendly fire. Alongside the small troop of macrophages that stimulates defense measures, a larger squadron of macrophages halts immune activity when it threatens the host. Andrij Holian and his coworkers in Houston have found that people with healthy lungs normally have 10 times as many suppressor macrophages as stimulatory ones. In people with asthma and other chronic lung diseases -- who face an increased risk of respiratory disease from inhaling urban dust -- that ratio may be only 3 to 1. The reason for the difference is not known. In a report to be published in the March Environmental Health Perspectives, Holian’s team describes test-tube studies of human alveolar macrophages. The macrophages showed no response to ask collected from the Mount St. Helen’s eruption. However, when exposed to airborne dust from St. Louis and Washington, D. C. , most of the suppresser macrophages underwent apoptosis, or cellular suicide, while the stimulatory ones survived unaffected. Ash from burned residual oil, a viscous boiler fuel, proved even more potent at triggering suppressor cell suicides. It this test-tube system models what’s actually happening in the human lung, Holian told Science News, the different responses of the two classes of lung macrophages could result in an overly aggressive immune response to normal triggering events. Indeed, he says, it would be the first step in a cascade that can end in inflammatory lung injury. "We may one day be able to target this up stream event and prevent that injury." "This is, I think, an important contribution to the overall story," says Daniel L. Costa of EPA’s pulmonary toxicology branch in Research Triangle Park, N.C. Studies by EPA suggest that certain metals -- especially iron, vanadium, nickel, and copper -- in smoke from combustion of fossil fuels trigger particularly aggressive inflammatory responses by lung cells. Costa says these metals play a "preminent" role in the toxicity of airborne particulates. When EPA researchers removed the metals, they also removed the toxicity, he says. Moreover, he notes, these metals tend to reside on the smallest water-soluble particles in urban air --the fraction targeted for more aggressive controls under the new rules. John Vandenberg, assistant director of EPA’s National Health and Environmental Effects Research Laboratory in Research Triangle Park, says Holian’s results are "a nice complement to our studies." This passage is mainly about ______.
Where will Denis spend his holiday
Look at the picture. It is a nice classroom. In the picture, you can see the teacher’s desk, ten desks and chairs. You can see a boy and three girls. The girl in blue hat is Lucy. The girl in red coat is Lily. And the girl in green shirt is Beth. The boy is Jim. They are the same age. I think they are in the same class. Lucy’s pencils are on the desk. Lily’s book is on the teacher’s desk. You can’t see the teacher. Where’s the teacher He is behind the door. The teacher stands in front of the blackboard.
TEXT B An invisible border divides those, arguing for computers in the classroom on the behalf of students career prospects and those arguing for computers in the classroom for broader reasons of radical educational reform. Very few write on the subject: have explored this distinction -- indeed, contradiction -- which goes to the heart of what is wrong with the campaign to put computers in the dark. An education that aims at getting a student a certain kind of job is a technical education, justified for reasons radically different from why education is universally required by law. It is not simply to raise everyone’s job prospects that all children are legally required to attend school into their teens. Rather, we have a certain conception of the American citizen, a character who is incomplete if he cannot competently asses how his livelihood and happiness are affected by things outside of himself. But this was not always the case, before it was legally required for all children to attend school until a certain age. It was widely acteristic of all industrialized countries, we came to accept that everyone is fit to be educated. Computer education advocates forsake this optimistic notion for a pessimism that betrays their otherwise cheery out-look. Banking on the confusion between educational and vocational reasons for bringing computers into schools, computer advocates often emphasize the job prospects of graduates over their educational achievement. There are some good arguments for a technical education given the right kind of student. Many European schools introduce the concept of professional training early on in order to make sure children are properly equipped for the profession they want to join. It is, however, presumptuous to insist that there will only be so many jobs for so many scientists, so many businessmen, so many accountants. Besides, this is unlikely to produce the needed number of every kind of professional in a country as large as ours and where the economy is spread over so many states and involves so many international corporations. But, for a small group of students, professional training might be the way to go since well-developed skills, all other factors being equal, can be the difference between having a job and not. Of course, the basics of using any computer these days are very simple. It does not take a life-long acquaintance to pick up various software programs. If one wanted to become a computer engineer, that is of course, an entirely different computer skills are only complementary to the host of great skills that are necessary to becoming any kind of professional. It should be observed, of course that no school, vocational or not, is helped by a confusion over its purpose. The belief that education is indispensable to all children ______.
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