仔猪水肿病菌苗制备及免疫效力的测定

用致仔猪水肿病的溶血性大肠杆菌制备氢氧化铝苗、蜂胶苗、油佐剂苗和超声波灭活苗,分别以0.1mL、0.2mL剂量免疫小白鼠,在免疫后24d用强毒株培养液攻击,结果显示:0.1mL氢氧化铝苗、0.2mL 蜂胶苗可使小白鼠获得100％的保护。0.1mL超声波灭活苗可使小白鼠获得80％的保护。用不同菌液免疫家兔,在免疫后21d、27d采血测其凝集抗体效价,21d、27d皆以油佐剂苗效价最高,达1:32、1:64,其次为蜂胶苗,为1:32(++)、1:32(++++)。     

中国农地制度的合理性探微：一个组织的制度分析范式

中国农村土地制度长期坚持以集体所有和家庭承包为内核，这不仅是国家层面的主观需要，也有集体和家庭分别作为两种制度安排的内在合理性。集体和家庭都体现着长期历史的自然选择，法律的规定只是让原有的非正式制度显化为正式的制度安排，外加非正式制度的配合，农地制度更易形成有效率的制度结构；集体和家庭在不同时期表征不同的功能，节约不同层次的交易费用，它们均具有较强的适应农地制度变革的能力。深化农地集体所有制改革需契合客观存在的自然法序，注重正式制度与非正式制度的功能配合，增强中国农地制度的稳定性和灵活性。     

改善全息圆锥准直线及提高准直精度的一种方法

用一张计算全息图可产生锥面波,锥面波衍射图样的中心在空间是连续的,可作为直线基准。本文提出了提高锥面波直线准直精度的一种方法即空间滤波法。实验结果与理论分析一致。     

The World Fertility Survey: an appraisal of methodology

"In the first half of the article, a broad account of content and procedures is given. In conduct of individual surveys, the achievements of the World Fertility Survey were based on thoroughness rather than technical superiority. The later aspects of the program, including analysis, archiving, and data dissemination, were more innovative and represent models of excellence for similar future enquiries. In overall terms, the program is judged to be an expensive success. In the second half of the article, two methodological issues are discussed in more detail: the collection of retrospective birth histories and the translation of survey instruments into local languages." Comments by Anthony G. Turner (pp. 768-9), Kweku T. de Graft-Johnson (pp. 769-70), Burton Singer (pp. 771-2), and Joel E. Cohen (pp. 772-4) are appended.     

Diet,mortality and life expectancy: a cross national analysis

"There are numerous reasons why mortality and life expectancy vary between countries. Epidemiological studies seem to indicate that dietary variations may be among them. A sample of 51 countries studied with data from the International Comparisons Project and other sources, shows that after controlling for nutrient intake, consumption of medical goods and services, income distribution, weather, and literacy, countries with more meat and poultry in their diet have lower life expectancies after age five. The results for infant mortality and child death between one and five indicate that a more animal-intensive diet may be actually beneficial, especially if fish consumption is increased and meat and poultry consumption reduced."     

Immigration and the earnings of youth in the U.S.

"This article reports findings that have emerged from an effort made at statistically measuring the effects of immigration on the earnings of U.S.-born youth. The presence of immigrants arriving before 1965 has a positive impact on youth earnings. Recently arrived immigrants impact negatively, however. These results are consistent with recent findings that the skill level of immigrants arriving within the last two decades is lower relative to that of immigrants arriving earlier. The results also show that the negative effects diminish as the youth ages, reflecting skill acquisition and job mobility of the young worker into jobs less vulnerable to competition from immigrant workers."     

International Conference on Population Aging. Keynote address

This is the keynote address of H.E.Dr. Vincent Tabone, President of Malta, at the International Conference on Aging, which was held in San Diego in September 1992. He states that the conference celebrates the tenth anniversary of the Vienna International Plan of Action, and provides an opportunity to evaluate progress and plan future direction. Dr. Tabone, as Minister of Foreign Affairs, first introduced the question of aging at the UN General Assembly over twenty years ago; the United Nations Secretariat established its first program in the field of aging in 1970. At the World Assembly on Aging in 1982, all members adopted the International Plan of Action, which defined guidelines for policies and programs in support of the aging populations. As a direct result of this, and in support of the needs of developing countries, the UN signed an agreement with the government of Malta that established the International Institute on Aging as an autonomous body under the auspices of the UN; it is the major expression of the Vienna Plan of Action. Concern for aging populations has developed enough maturity and momentum to oversee its own progress. Although current events may relegate the social and economic implications of the aged to the sphere of rhetoric, they demand thinking in terms of generations and transcend all political boundaries. This conference will evaluate progress toward deflecting a situation where the elderly constitute an increasing proportion of the population, without adequate and appropriate provision for their livelihood, and could have direct bearing on encouraging and ensuring the continuity of the family's vital and traditional role in preserving the dignity, status, and well-being of its aging members. A nation which begrudges its dues to the elderly, the successful products of society and triumphs of life, denies its past. This conference is a reaffirmation of commitment to the United Nations Principles for Older Persons, an omen of the review of the Global Targets on Aging for the year 2001 by the General Assembly at its forty-seventh session in October, and a stepping stone in the path toward integrating the elderly more fully into the mainstream of society. The year 1992 is a year for solidarity between the generations.     

HIV testing of health care workers

Until recently, nothing much beyond education and the dispensing of condoms was being done to control the spread of AIDS. We have not yet taken sufficient measures to prevent the spread of this disease. Instead, we insist on protecting the privacy of the HIV-positive individual. However, we ignore the right to privacy by mandating testing for syphilis, which is not nearly as serious a disease as AIDS. Now, mandatory testing of health care workers is being proposed more frequently.     

Immigrant fertility: an examination of social characteristics and assimilation

"This study compares the fertility patterns of foreign-born and native-born women in Canada and examines whether [the] same set of social characteristics accounts for differential fertility among both the groups. The study also assesses the importance of social characteristics and assimilation on immigrant fertility behavior. Two generations of currently married/cohabiting women with spouse present are analyzed using multiple regressions. The results reveal similar effects on fertility of social characteristics for foreign-born and native-born, while in the case of younger generations the effects are stronger."