<Emphasis Type="BoldItalic">MAD-STEC</Emphasis>: a method for multiple automatic detection of space-time emerging clusters

Crime or disease surveillance commonly rely in space-time clustering methods to identify emerging patterns. The goal is to detect spatial-temporal clusters as soon as possible after its occurrence and to control the rate of false alarms. With this in mind, a spatio-temporal multiple cluster detection method was developed as an extension of a previous proposal based on a spatial version of the Shiryaev–Roberts statistic. Besides the capability of multiple cluster detection, the method have less input parameter than the previous proposal making its use more intuitive to practitioners. To evaluate the new methodology a simulation study is performed in several scenarios and enlighten many advantages of the proposed method. Finally, we present a case study to a crime data-set in Belo Horizonte, Brazil.     

A new estimator of entropy

Vasicek (1976) proposed an estimator of entropy based on spacings. A new estimator of entropy is proposed. This new estimator is based on local linear regression. Comparisons between this new estimator and Vasicek's estimator are made. The mean square error (MSE) of the new estimator is consistently smaller than the MSE of Vasicek's estimator.     

Focused estimation for noisy and small data sets: a Bayesian minimum expected loss estimator approach

Central to many inferential situations is the estimation of rational functions of parameters. The mainstream in statistics and econometrics estimates these quantities based on the plug‐in approach without consideration of the main objective of the inferential situation. We propose the Bayesian Minimum Expected Loss (MELO) approach focusing explicitly on the function of interest, and calculating its frequentist variability. Asymptotic properties of the MELO estimator are similar to the plug‐in approach. Nevertheless, simulation exercises show that our proposal is better in situations characterised by small sample sizes and/or noisy data sets. In addition, we observe in the applications that our approach gives lower standard errors than frequently used alternatives when data sets are not very informative.     

Harassment at work? Empowerment and autonomy as coping strategies of young workers

There is a considerable number of researches about workplace violence, but few relate young workers and work harassment. This study aimed to investigate the reported perceptions of young apprentices and trainees about moral harassment at work and related coping strategies. Forty adolescent workers (22 men and 18 women) between 15 and 20 years old who received training by a non-governmental organization in S?o Paulo, Brazil, participated in the study. Data collection included individual and collective interviews. It was used an in-depth semi structured interview protocol. The discourses were analyzed using the hermeneutic-dialectic frame. Results showed that young workers reported little or no knowledge of strategies to cope with moral harassment at work, showing vulnerability to the effects of aggression. Effective coping strategies at work should embrace two important concepts of health promotion: empowerment and autonomy.     

HIV diffusion patterns and mobility: Gender differences among drug users

Researchers have recently expanded the scope of study of transmission patterns of AIDS to incorporate spatial and geographical questions. United States diffusion patterns of this disease appear to indicate that it may emanate from urban area epicenters to areas of low and moderate prevalence. The travel patterns of injecting drug users (IDUs) and the extent to which they engage in high risk drug and sexual activities was examined as an explanation of diffusion of the HIV virus from one community to another. The study population of 49,621 was comprised of subjects recruited from approximately 60 sites nationwide from 1988–1991. While the data are limited in some ways, they partially support a diffusion explanation of HIV transmission for males and females. The analysis demonstrates that low prevalence cities were significantly more likely to have been the destinations of both men and women who engaged in high risk drug and sexual activities. In addition, HIV seropositive drug users who engaged in high risk drug and sexual behaviors in destination cities were more likely than seronegatives to travel to high or low seroprevalence areas than to moderate prevalence areas. The findings suggest a need for effective HIV prevention educational messages about the risks of traveling and participating in high risk activities.     

School counsellors and cultural diversity management in Spanish secondary schools: the role of relations with other educators and intervention models used in care of immigrant students

During the last 20 years, the influx of immigrant pupils in Spanish schools has taken up much of school counsellors’ agendas. This leads us to reflect upon the status and role of educational guidance in terms of cultural diversity management, particularly focusing on two elements that may potentially help understand the situation: relations with other educational agents and the intervention model applied. The field work for this study was carried out during an academic semester in four secondary schools in Huelva. In addition to the analysis of official school documentation, remarks and field notes, semi-structured interviews were carried out and a discussion group was held with the four counsellors. Counsellors are trying to overcome an intervention model that is mainly therapeutic in nature and make space in their schedules for a way of working that is more focused on prevention and advisory services, incorporating the participation of other educational actors. But this is not an easy task. The possibility of generating changes would encourage better integration of cultural diversity in the life of schools, rather than treating it as a negative/deficit view, as an occasional issue, individual and isolated from the sum of school activities and other members of the education community.     

Experimentation order with good properties for 2 k factorial designs

Randomizing the order of experimentation in a factorial design does not always achieve the desired effect of neutralizing the influence of unknown factors. In fact, with some very reasonable assumptions, an important proportion of random orders achieve the same degree of protection as that obtained by experimenting in the design matrix standard order. In addition, randomization can induce a large number of changes in factor levels and thus make experimentation expensive and difficult. De Leon et al. [Experimentation order in factorial designs with 8 or 16 runs, J. Appl. Stat. 32 (2005), pp. 297–313] proposed experimentation orders for designs with eight or 16 runs that combine an excellent level of protection against the influence of unknown factors, with the minimum number of changes in factor levels. This article presents a new methodology to obtain experimentation orders with the desired properties for designs with any number of runs.     

Language Provisions Under the Voting Rights Act: How Effective Are They?*

Objectives. As the Voting Rights Act (VRA) comes up for renewal in 2007, its effects on the political incorporation of groups other than African Americans will be of key importance in any debate. Among the questions in any such discussion will be whether the language provisions of the VRA have helped enfranchise “linguistic minorities” in the United States, or whether their effect has been largely symbolic. Second, if the Voting Rights Act has had a positive impact on the participation rates of Asian Americans and Latinos, have these effects been tilted toward first‐generation immigrants—who were not the intended beneficiaries of the Act—rather than native‐born minorities? Methods. This article looks at registration and voting data from the November 1996 and 2000 Census Current Population Supplemental Voting Surveys to explore the differential impact of the Act among immigrants and the native born, and among Latinos and Asian Americans. Results. The analysis finds evidence that the language provisions of the Voting Rights Act have significant and positive effects on the voting rates of covered linguistic minorities. Conclusions. Because the voting rates of Asian and Hispanic Americans in the United States still lag behind those of the population as a whole, the effects of the VRA with respect to these groups are important considerations as Congress weighs the Act's renewal.     

Older and Wiser: How CEOs’ Time Perspective Influences Long‐Term Investments in Environmentally Responsible Technologies

Most theories of corporate governance argue that chief executive officers (CEOs) take less risk as they near the end of their career, and therefore are less likely to make major investments. This prediction is based on decisions related to firm‐specific benefits; however, it may not be generalizable to decisions that involve broad societal goals. In terms of societal investments, CEOs with a longer time perspective may be more likely, rather than less likely, to invest. In this paper, we argue that a CEO's future time perspective is fostered by shorter career horizons, longer tenures, higher organizational ownership and less short‐term compensation. We test these hypotheses on 150 observations from the US investor‐owned electric power generation sector over a three‐year unbalanced sample (64.3% of the population). We applied random‐effects generalized least squares (GLS) estimations to test our hypotheses, and found support for three out of four hypothesized relationships.