Evaluation of two school-based HIV prevention interventions in the border city of Tijuana, Mexico

This research project examined the individual and combined effectiveness of an HIV prevention workshop and a free condom distribution program in four high schools in Tijuana, Mexico. Adolescents (N = 320) completed baseline measures on sexual practices and theoretical correlates and participated in a two-part study. In Study 1, students were randomly assigned to an HIV prevention workshop or a control condition, with a 3-month follow-up assessment. Results indicate three significant workshop benefits regarding HIV transmission by altering sexual initiation, access to condoms, and traditional beliefs regarding condoms. In Study 2, we set up a condom distribution program at two of the participating schools, and students completed a 6-month follow-up assessment. Results indicate that exposure to the workshop followed by access to the condom distribution program yielded two beneficial results for reducing HIV transmission: moderating sexual initiation and increasing condom acquisition. Access to the condom distribution program alone had no effects on behavioral and psychosocial correlates of HIV transmission. We discuss implications of these results.     

A simulation study of the operations of a telephone bureau

This paper presents a priority queueing situation: a telephone bureau which has to deal with two distinct classes of caller. The first group are making urgent calls which must be dealt with as soon as possible, while the second group are making a variety of different types of routine enquiry which are not considered to be as important. Management are concerned with a number of issues associated with the operations of their bureau, these include the levels of service offered to the different groups of caller, the effects of different levels of staffing, and the effects of changing the mix of call types. The use of applied probability theory to analyse this situation is briefly discussed, and then simulation proposed as a means to analyse the operations of the bureau. The development of this simulation is outlined, some typical results presented and its usefulness discussed.     

The application of microcomputers in production management

The findings reported result from a questionnaire survey, and a number of company interviews. Further questions which need to be answered are identified, and a research project to provide these answers is outlined.     

Investigating Health Selection Within Mexico and Across the US Border

Despite acquiring lower levels of attainment and earnings, Mexican immigrants exhibit favorable health outcomes relative to their native-born counterparts. And while scholars attempt to reconcile this so-called paradoxical relationship with a variety of theoretical and empirical approaches, patterns of selective migration continue to receive considerable attention. The present study contributes to the literature on health selection by extending the healthy migrant hypothesis in a number of ways. First, we rely on a unique combination of datasets to assess whether the healthy are disproportionately more likely to migrate. We use the latest wave of the Mexican Family Life Survey and the 2013 Migrante Study, a survey that is representative of Mexican-born persons who are actively migrating through Tijuana. Pooling these data also allow us to differentiate between internal and US-bound migrants to shed light on their respective health profiles. Results provide modest support for the healthy migrant hypothesis. Although those who report better overall health are more likely to migrate, we find that the presence of certain chronic conditions increases migration risk. Our findings also suggest that internal migrants are healthier than those traveling to the US, though this is largely because those moving within Mexico reflect a younger and more educated population. This study takes an important step in uncovering variation across migrant flows and highlights the importance of the timing at which health is measured in the migration process.     

The use of formal inventory control models: A preliminary survey

Of the many papers and texts on the subject of inventory control, relatively few report the successful implementation of systems based on formal mathematical models developed with specific objectives in mind. This could be considered rather strange in the light of the relatively high number of papers reporting the development of models for dealing with a multitude of different hypothetical situations, and the widespread availability of computer systems capable of exploiting such models. Various reasons for this anomaly can be put forward. This paper reports the results of a preliminary survey designed to investigate this more deeply, and draws some necessarily tentative conclusions relating to factors contributing to the successful application of such systems.     

How Do Tougher Immigration Measures Affect Unauthorized Immigrants?

The recent impetus of tougher immigration-related measures passed at the state level raises concerns about the impact of such measures on the migration experience, trajectory, and future plans of unauthorized immigrants. In a recent and unique survey of Mexican unauthorized immigrants interviewed upon their voluntary return or deportation to Mexico, almost a third reported experiencing difficulties in obtaining social or government services, finding legal assistance, or obtaining health care services. Additionally, half of these unauthorized immigrants reported fearing deportation. When we assess how the enactment of punitive measures against unauthorized immigrants, such as E-Verify mandates, has affected their migration experience, we find no evidence of a statistically significant association between these measures and the difficulties reported by unauthorized immigrants in accessing a variety of services. However, the enactment of these mandates infuses deportation fear, reduces interstate mobility among voluntary returnees during their last migration spell, and helps curb deportees’ intent to return to the United States in the near future.     

A comparison of applications of microcomputers in production

Earlier research has established that the full potential of microcomputers is not being achieved by production management in small companies. Moreover, questionnaire results and in-company interviews were used to support suggested reasons for this situation. This paper reports further work carried out to examine the issues raised in far more detail. Collaboration took place with nine separate companies over a range of applications. Three of these case studies are presented in detail, and general conclusions drawn relating both to these specific studies and to the total collaboration.     

Moving Beyond Salmon Bias: Mexican Return Migration and Health Selection

Despite having lower levels of education and limited access to health care services, Mexican immigrants report better health outcomes than U.S.-born individuals. Research suggests that the Mexican health advantage may be partially attributable to selective return migration among less healthy migrants—often referred to as “salmon bias.” Our study takes advantage of a rare opportunity to observe the health status of Mexican-origin males as they cross the Mexican border. To assess whether unhealthy migrants are disproportionately represented among those who return, we use data from two California-based studies: the California Health Interview Survey; and the Migrante Study, a survey that samples Mexican migrants entering and leaving the United States through Tijuana. We pool these data sources to look for evidence of health-related return migration. Results provide mixed support for salmon bias. Although migrants who report health limitations and frequent stress are more likely to return, we find little evidence that chronic conditions and self-reported health are associated with higher probabilities of return. Results also provide some indication that limited health care access increases the likelihood of return among the least healthy. This study provides new theoretical considerations of return migration and further elucidates the relationship between health and migration decisions.