An Empirical Strategy to Detect Spurious Effects in Long Memory and Occasional-Break Processes

Long-range dependence and structural changes in level are intimely related phenomena and it is very difficult to separate the two effects. In this article, we present an empirical procedure to distinguish between long-memory and occasional-break processes. An extensive Monte Carlo experiment illustrates the performance of the procedure and an application to real data is also included.     

Generic charisma - Conceptualization and measurement

In these times, when fame is available to almost anyone, it is worth being able to measure the extent and dimensions of a person's charisma. Most of the research on charisma to date is restricted to the area of leadership. In this article, however, charisma is generalized to take in all human beings and is conceptualized as a multi-dimensional cognitive-affective phenomenon. The article presents a pilot study aimed at providing an adequate operational definition of the construct as well as an initial tool for its measurement. A following literature review shows how authors have developed the concept of charisma and its initial operational dimensions for empirical research. A questionnaire is developed in three stages. The factor analyses applied in stages two and three point towards a six-factor solution (i.e. six dimensions of charisma). Further analysis reveals that the developed instrument is reliable and viable as well as applicable for future theoretical and practical work.     

ARFIMA processes and outliers: a weighted likelihood approach

In this paper, we consider the problem of robust estimation of the fractional parameter, d, in long memory autoregressive fractionally integrated moving average processes, when two types of outliers, i.e. additive and innovation, are taken into account without knowing their number, position or intensity. The proposed method is a weighted likelihood estimation (WLE) approach for which needed definitions and algorithm are given. By an extensive Monte Carlo simulation study, we compare the performance of the WLE method with the performance of both the approximated maximum likelihood estimation (MLE) and the robust M-estimator proposed by Beran (Statistics for Long-Memory Processes, Chapman & Hall, London, 1994). We find that robustness against the two types of considered outliers can be achieved without loss of efficiency. Moreover, as a byproduct of the procedure, we can classify the suspicious observations in different kinds of outliers. Finally, we apply the proposed methodology to the Nile River annual minima time series.     

Physical activity is inversely related to drug consumption in elderly patients with cardiovascular events

Elderly patients with cardiovascular events are characterized by high drug consumptions. Whether high drug consumptions are related to physical activity is not known. In order to examine whether physical activity is related to drug consumption in the elderly, patients older than 65 years (n?=?250) with a recent cardiovascular event were studied. Physical activity was analyzed according to the Physical Activity Scale for the Elderly (PASE) score and related to drug consumption. PASE score was 72.4?±?45.0 and drug consumption was 8.3?±?2.2. Elderly patients with greater comorbidity took more drugs (8.7?±?2.1) and are less active (PASE?=?64.4?±?50.6) than patients with Cumulative Illness Rating Scale severity score higher than 1.8 than those with a score lower than 1.8 (76.3?±?41.4, p?<?0.05, and 8.0?±?2.0, p?=?0.006, respectively). Multivariate analysis correlation confirmed that PASE score is negatively associated with drug consumption (β?=??0.149, p?=?0.031), independently of several variables including comorbidity. Thus, physical activity is inversely related to drug consumption in elderly patients with cardiovascular events. This inverse relationship may be attributable to the high degree of comorbidity observed in elderly patients in whom poor level of physical activity and high drug consumption are predominant.     

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.     

Digital natives and social media

Digital natives (also known as “Generation Y” and “Millennials”), a generation born during of after introduction of digital technologies, 1980s and after, have mixed preferences for media use in personal and professional lives. A study by Friedl and Tkalac Ver?i? (2011) showed that even though digital natives prefer digital media in their personal lives, this is not necessarily reflected in their business lives. This study addressing preferences of “traditional” vs. “the new media” in a university setting found an opposite result.     

Supporting the allocation of software development work in distributed teams with multi-criteria decision analysis

In the fast moving software industry, projects have been increasingly developed by distributed teams, which are located in geographically remote offices and collaborate using information communication technologies. In such environments, project distribution presents specific challenges, as work in distributed teams increases project technical complexity, communication lines multiply and stakeholders’ interests may be divergent. Despite the importance and complexity of this type of problem, it seems that there is a lack of reports, in the literature, of systems that could support these decisions. This paper presents a real-world case study, where we developed a multi-criteria model for supporting the distributed team work allocation decision for a major global software company. It was developed with a group of software development project managers, using decision conferencing and multi-attribute value analysis. The model deals not only with software engineering attributes, but also “soft” and strategic issues, like team satisfaction and training opportunities. We also discuss some issues and challenges faced during this modelling process.     

Child care outcomes: economic perspectives and issues

Economics starts with the observation of widespread scarcity and the consequent need for choices about resource allocation. Common criteria for such choices are economy, effectiveness, efficiency and equity. This paper defines these criteria and locates them within a conceptual framework (the ‘production of welfare’). It also examines some of the reasons for the growth in interest in them. The main modes of evaluation—cost-benefit, cost-effectiveness, cost-utility and cost-consequences analyses—are described and illustrated. Few such evaluations have been conducted in child care, and the paper ends with speculation as to why this is so.