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A means of accurate investigation of structural parameters of GaxAl1-(Sub x)Sb/GaSb single QWs grown by MBE on GaSb substrates is carried out by means of HRXRD, XSW, and HREM techniques. The effect of the surface degradation of the upper GaAlSb layers due to the chemical reaction with the atmosphere is considered.

An impact evaluation of an integrated school- and health-clinic-based adolescent reproductive health initiative was undertaken by the State Secretariats of Health and Education in Bahia, Brazil during 1997-99. The project was initiated in response to continued high pregnancy rates among adolescents and growing numbers of new HIV infections among young adults. It sought to promote responsible sexual and health-seeking behaviors among public secondary-school students, including the use of public health clinics. The study design included a matched control group used to measure project impact. The findings indicate that the project was successful in increasing the flow of sexual and reproductive health information to secondary-school students and that it had an impact on adolescents' intentions to use public health clinics in the future. No effects on sexual or contraceptive-use behaviors or on use of public clinics were observed, however. Client exit-interview data from a subset of project clinics indicate that adolescents who use clinic-based services are overwhelmingly female and considerably older on average and much more likely ever to have been pregnant than are adolescents in the target population for the project. [ABSTRACT FROM AUTHOR]

Recent data indicate that adolescent fertility rates in Peru remain high and that Peruvian adolescents and young adults account for a disproportionate share of new HIV infections. The present study was undertaken to identify key risk and protective factors for early sexual activity and unprotected sex among secondary-school students in nine large cities in Peru. Survey data from 6,962 students aged 13-18 are consistent with existing research in indicating that behaviors of Peruvian youth are influenced in important ways by many factors. In the present study, these included region of residence, family economic position, family structure, working for pay, peer behaviors, and self-esteem. Knowledge of pregnancy and of the risks of acquiring sexually transmitted diseases and of the means of avoiding both did not, however, differentiate risk-takers from non-risk-takers. The study findings suggest a need for adolescent health programs to broaden their focus beyond the immediate proximate determinants of behavior, such as sexual and reproductive health knowledge and access to contraceptives, and also to target some of the key contextual factors influencing adolescent behavior. [ABSTRACT FROM AUTHOR]

Although the extent to which organized family planning programs influence reproductive preferences remains a subject of debate, most observers would grant that such programs play a key role in helping individuals to realize their contraceptive and reproductive intentions. However, few prior studies have quantified the magnitude of this facilitating or enabling effect of family planning services, given existing demand for contraception. This study takes advantage of panel survey data and linked information on the supply environment for family planning services in Morocco in order to bridge this research gap. In the analysis, contraceptive use during the 1992-95 period is related to contraceptive intentions in 1992; individual-, household-, and community-level determinants of contraceptive behavior; and family planning supply factors. Estimation procedures are used that control for unobserved joint determinants of contraceptive intentions and use. Evidence of a significant enabling or facilitating role of family planning services is found, and the results also suggest that family planning program factors influence contraceptive intentions in important ways. [ABSTRACT FROM AUTHOR]

Background: Despite large investments in basic primary health care in sub-Saharan Africa over the past two decades, quantifying the contribution of national programme efforts to the reduction of infant/child mortality in the region has proven difficult. This study takes advantage of the phased implementation of the national Rural Health Improvement Program in Niger and conveniently timed survey data to reassess programme impact on under-five mortality during the 1980-1985 period.Methods: Health service use and under-five mortality rates for children born in the 5 years prior to the 1985 survey are compared for three groups of villages: villages served by a dispensary, villages served by village health teams (VHT), and villages without access to modern primary care services. Multi-level regression analyses using both household- and community-level variables are undertaken in estimating the magnitude of effects.Results: Children residing in villages proximate to health dispensaries were approximately 32% less likely to have died during the study period than children without access to modern health services. Village health teams were not, however, associated with significantly lower mortality probabilities. Formal test for endogeneity indicated that these effects were not the result of non-uniform/non-random allocation of resources.Conclusions: The findings are largely supportive of the key premise underlying selective primary health care interventions - that packages of basic services can be effectively mounted nationally in poor countries and have a significant impact over a short time period. In Niger, less than optimal implementation of VHT appears to have reduced the magnitude of the impact achieved. [ABSTRACT FROM AUTHOR]

Background: Although the Expanded Programme on Immunization (EPI) cluster survey methodology has been successfully used for assessing levels of immunization programme coverage in developing country settings, certain features of the methodology, as it is usually carried out, make it less-than-optimal choice for large, national surveys and/or surveys with multiple measurement objectives. What is needed is a 'middle ground' between rigorous cluster sampling methods, which are seen as unfeasible for routine use in many developing country settings, and the EPI cluster survey approach.Methods: This article suggests some fairly straightforward modifications to the basic EPI cluster survey design that put it on a solid probability footing and render it easily adaptable to differing and/or multiple measurement objectives, without incurring prohibitive costs or adding appreciably to the complexity of survey operations. The proposed modifications concern primarily the manner in which households are chosen at the second stage of sample selection.Conclusions: Because the modified sampling strategy maintains the scientific rigor of conventional cluster sampling methods while retaining many of the desirable features of the EPI survey methodology, the methodology is likely to be a preferred 'middle ground' survey design, relevant for many applications, particularly surveys designed to monitor multiple health indicators over time. The fieldwork burden in the modified design is only marginally higher than in EPI cluster surveys, and considerably lower than in conventional cluster surveys. [ABSTRACT FROM AUTHOR]

This study examines effects and interactions of socioeconomic status, access to water supply and sanitation, and breast-feeding practices in relation to child growth in two provincial cities in the Philippines. Multivariate analysis identified food expenditure per head, education of the household head and gender of the child as significant predictors of nutritional status. The duration of partial and full breast-feeding was negatively (though non-significantly) associated with growth. Sanitation facilities and breast-feeding are, however, important determinants during the first year of life. Among children over 1 year of age, socioeconomic variables and gender are the most important predictors. Breast-feeding is shown to provide more important health benefits for children in lower income households. The need for further studies on the causes of gender differences in nutritional status was apparent. [ABSTRACT FROM PUBLISHER]