<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.     

TEACHING THE PRODUCTION/OPERATIONS MANAGEMENT CORE COURSE: INTEGRATING LOGISTICS PLANNING ACTIVITIES

This paper discusses the benefits of restructuring the introductory undergraduate production and operations management (pom) course to improve its pedagogical effectiveness and to better convey the importance of integrating logistics planning activities. The introduction of a dynamic integrative semester-long case study which involves students in applying pom concepts and tools through a simulation game is reported.     

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.     

The dynamics of hapū research relationships

Abstract

The Whakaki Lake Trust has a long history of being an active kaitiaki of Whakaki Lake and has developed a hapū-based restoration and enhancement programme at the Lake property. Part of this programme has involved working with a range of external agencies and researchers. Research relationships have become an important part of the restoration process to build the capability and capacity of hapū to execute activities associated with restoration. In addition, relationships have provided an opportunity to strengthen and expand the knowledge base that hapū can draw upon to inform ecological restoration and resource management decisions. Some of these relationships have been adversarial and a source of much frustration. As a consequence the Trust has developed very clear expectations and policy around working with others. My experience of developing a doctoral research project with Whakaki Lake Trust is used here to discuss hapū expectations of research and resultant academic dilemmas.     

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.     

Penalized Maximum Likelihood Estimator for Normal Mixtures

The estimation of the parameters of a mixture of Gaussian densities is considered, within the framework of maximum likelihood. Due to unboundedness of the likelihood function, the maximum likelihood estimator fails to exist. We adopt a solution to likelihood function degeneracy which consists in penalizing the likelihood function. The resulting penalized likelihood function is then bounded over the parameter space and the existence of the penalized maximum likelihood estimator is granted. As original contribution we provide asymptotic properties, and in particular a consistency proof, for the penalized maximum likelihood estimator. Numerical examples are provided in the finite data case, showing the performances of the penalized estimator compared to the standard one.