环境氡所致肺剂量影响因素的实验研究

在环境氡水平的房间内，研究各种处理空气的方法所引起室内α潜能浓度、平衡因子、非结合态氡子体份额和气溶胶粒子数目及其大小分布的变化．计算支气管基底细胞层、肺区上皮及总肺的单位氡浓度年当量剂量，并与封闭房间未经任何空气处置的情况比较，结果显示：用正离子加风扇对流时总肺剂量率减少最为明显；而空调通风，对支气管剂量率的减少最为有效；吸烟或施放油烟，肺剂量都明显增加，油烟的影响尤为严重．     

Interaction of factors related to lactation duration

Perceived social support and interpersonal dependency were studied as potential factors associated with lactation duration based upon previous breastfeeding experience. Inexperienced breastfeeding mothers perceived more social support than experienced breastfeeding mothers did. Perceived social support was not significantly correlated with lactation duration. An ancillary finding was that women providing a combination of breast milk and human milk substitutes had significantly lower social self-confidence than did mothers providing breast milk exclusively.     

Family poverty, welfare reform, and child development

Our review of research suggests that family poverty has selective effects on child development. Most important for policy are indications that deep or persistent poverty early in childhood affects adversely the ability and achievement of children. Although the 1996 welfare reforms have spurred many welfare-to-work transitions, their time limits and, especially, sanctions are likely to deepen poverty among some families. We suggest ways policies might be aimed at preventing either economic deprivation itself or its effects.     

A 10-year follow-up survey of programs and services for students with learning disabilities in graduate and professional schools

This 10-year follow-up study compares programs and services for students with learning disabilities (LD) in graduate and professional schools between 1985 and 1995. In 1995, surveys were sent to the same institutions (n = 682) as in the earlier survey, with a response rate of 30.6%. Significant changes over the 10 years include a higher level of awareness about LD and evidence of greater compliance with Section 504, a greater specificity of assessments required for the identification of students who receive services, improvements in the types and extent of services available, and increased program visibility. Despite these positive changes, 24% of the respondents indicated that they did not have a coordinator for LD at their institution, and 33% did not have a written plan for services. Eighteen institutions with programs or services for students with LD gave permission to publish their names. Implications and recommendations are discussed.     

人口教育概念的重新定义

最初给人口教育下定义的尝试没有能制订出一个让所有国家都信服的结构紧凑的概念。更确切地说,早期的一些被许多国家所采用的概念只包括了大致的指导方针。 虽然这个研究领域的专家们普遍认为人口教育应该致力于宏观国家的和微观家庭及     

西西弗斯（上）

我希望你们听过了关于清道的甲虫做球的奇怪的事情，还不至于厌倦。我已经告诉过你们神圣甲虫和西班牙的犀头，现在我想再讲一些这种动物的其他种类。在昆虫的世界里，我们遇到过许多模范母亲，现在只是为了好玩，来注意一回好的父亲吧!     

Childhood sexual abuse, adolescent sexual coercion and sexually transmitted infection acquisition among homeless female adolescents

OBJECTIVE: To examine the relationship between childhood experiences of sexual abuse, sexual coercion during adolescence, and the acquisition of sexually transmitted infections (STIs) in a population of homeless adolescents. METHOD: Homeless adolescent females (N = 216) from a northwestern United States city were recruited by street outreach workers for a longitudinal study of STI epidemiology. Baseline data on childhood abuse and recent history of sexual coercion were used to predict physiologically confirmed STI acquisition over the subsequent 6 months. RESULTS: About 38% of all girls reported a history of childhood sexual abuse (CSA). Girls with a history of CSA were more likely to report recent sexual coercion. In turn, sexual coercion in the last three months was significantly associated with a higher number of sexual partners (but not with a greater frequency of intercourse or with lower rates of condom use). Number of sexual partners significantly predicted the future acquisition of an STI within 6 months. CONCLUSIONS: Interventions to reduce risky sexual behaviors in homeless adolescent females may need to consider the impact of CSA, particularly on the number of sexual partners during adolescence. However, it also should be noted that engagement in intercourse often results from coercion and is not voluntary in this population.     

Learning disabilities and risk-taking behavior in adolescents: a comparison of those with and without comorbid attention-deficit/hyperactivity disorder

Risk-taking behavior includes alcohol and drug use, delinquency, acts of aggression, sexual activity, and so on. Many studies have explored the relationship between adolescents and risk-taking behavior; however, only a few studies have examined this link in adolescents with learning disabilities (LD) or attention-deficit/hyperactivity disorder (ADHD). The purpose of the present study was to address that limitation by comparing the risk-taking behavior of adolescents with LD (n=230), with comorbid LD/ADHD (n=92), and without LD or ADHD (n=322) on their substance use, engagement in major and minor delinquency, acts of aggression, sexual activity, and gambling activities. The study also investigated whether psychosocial variables (e.g., well-being) may act as mediating variables that help explain between-group differences. Results suggest that it is a combination of the LD and the secondary psychosocial characteristics that explains why adolescents with LD and comorbid LD/ADHD more frequently engage in some risk-taking behavior.     

Fe salts as catalyst for the wet oxidation of o-chlorophenol

INTRODUCTION Chlorophenols (CPs) are chemicals widely used in industry to manufacture insecticides, herbicides, fungicides, biocides, and dye, are also found in the effluent of the pulp and paper mill industry, and are mainly man-made compounds, and have been recog-nized as organic pollutants of air, groundwater, soil and sediments. They are carcinogenic and stable in water. Most chlorophenols are listed as priority pol-lutants by the US Environmental Protection Agency (1988) due to th…