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In the early years of the Social Security program, public support for old-age pensions was high but knowledge and understanding about benefits and taxes were low. Understanding has greatly increased, even though the program has expanded, and support for Social Security has remained high. Data from the surveys and polls examined in this article indicate that support for Social Security was strong even during the late 1970's and early 1980's, when a fiscal crisis generated a crisis of confidence in the public's perception of the system's ability to pay benefits in the future. The proportion of the American public declaring confidence in the program declined sharply from a large majority with confidence (63 percent) in 1975 to a minority with confidence (39 percent) in 1978. Following the restoration of program financing through the provisions in the 1983 amendments, the trend has reversed. By 1988, nearly one-half of the public expressed confidence in the future of the Social Security program. For the most part, other aspects of public opinion regarding Social Security have shown great stability over the years. The program is popular and has been well-supported. Support for the Government to spend more for Social Security has been consistently high, as has support for benefits to increase with inflation and for benefits to increase even if it means higher taxes. Many individuals rely on income from Social Security or expect to rely on it when they retire. It is clear that the public wants the program to continue. If participation were optional, about three-fourths of the population would stay in the program.  相似文献   
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The Philadelphia Low-Intensity Community Supervision Experiment provides evidence on the effects of lowering the intensity of community supervision with low-risk offenders in an urban, US county community corrections agency. Using a random forests forecasting model for serious crime based on Berk et al. Journal of the Royal Statistical Society, Series A, 172(Part 1), 191–211, 2009, 1,559 low-risk offenders were identified and randomly assigned to either standard or reduced frequency of mandatory office visits. Treatment as assigned was substantially delivered at 4.5 probation visits per year versus 2.4, for as long as offenders remained on active probation or parole. In a one-year follow-up for all cases, outcomes examined were the prevalence, frequency, seriousness and time-to-failure of arrests for new crimes committed after random assignment was implemented. No significant differences (p = .05) in outcomes were found between standard and low-intensity groups. Non-significant differences for offense seriousness favored the low-intensity group. We conclude that lower-intensity supervision at the tested level of dosage can allow fewer officers to supervise low-risk offenders in the community without evidence of increased volume or seriousness of crime.  相似文献   
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利用从猪传染性胃肠炎病毒(TGEV)Miler株(M5C)克隆建立的一株重组杆状病毒(R2-2)表达的重组TGEV钉状糖蛋白(S),建立了一种阻断酶联免疫吸附试验(ELISA)来检测猪群抗TGEV抗体。试验表明,用重组病毒R2-2接种sf9细胞(spodopterafrugiperda)所表达的重组蛋白量在接种后第72h达到最高值;该重组蛋白能与抗TGEVS蛋白A位点的单克隆抗体特异性结合。用阻断ELISA检测68份来自无TGEV感染或TGEV(Purduel5)免疫的仔猪或母猪血清,结果与TGEV蚀斑减数试验完全相符,灵敏度和特异性均为100%。同时检测来自TGEV试验免疫猪、美国部分地区猪群、我国进口猪以及我国国内猪群血清627份,阳性检出率分别为82.61%、61.62%、58.33%和29.10%;用中和试验(微量中和试验或病毒蚀斑减数试验)检测的TGE血清抗体阳性率分别为80.87%、59.60%、56.11%和30.60%,两种方法对抗TGEV抗体的检出率没有显著差异。  相似文献   
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