A characterization of the geometric distribution

We show that for a simple random sample from a discrete distribution on the positive integers, the regression ofX _(2∶n) onX _(1∶n) is linear with unit slope if and only if the distribution is geometric.     

Confidence intervals for variance component ratios in unbalanced linear mixed models

Methods for constructing confidence intervals for variance component ratios in general unbalanced mixed models are developed. The methods are based on inverting the distribution of the signed root of the log-likelihood ratio statistic constructed from either the restricted maximum likelihood or the full likelihood. As this distribution is intractable, the inversion is rather based on using a saddlepoint approximation to its distribution. Apart from Wald's exact method, the resulting intervals are unrivalled in terms of achieving accuracy in overall coverage, underage, and overage. Issues related to the proper “reference set” with which to judge the coverage as well as issues connected to variance ratios being nonnegative with lower bound 0 are addressed. Applications include an unbalanced nested design and an unbalanced crossed design.     

Human Resource Management as a Field of Research*

Drawing on Snow and Thomas's (Journal of Management Studies, 31 (1994), pp. 457–480) matrix, we empirically explore the state of the art in human resource management (HRM) research. The data were obtained through a questionnaire directed to HRM scholars all over the world, in which they were asked about their particular theoretical and methodological approaches. The evidence obtained shows clearly that HRM scholars are progressively abandoning the universalistic perspective and completing their models with contingent and contextual variables. Trying to classify the different contributions proposed and discuss their integration, HRM is described as a field of research with three dimensions: subfunctional, strategic and international. The paper concludes that to provide reliable explanations and valid responses to professional problems, HRM research must advance simultaneously in these three dimensions. As follows from our analysis, there are certain HR issues that still need to be addressed: (1) the strategic use of HR practices, (2) their international applicability, (3) global HR strategies and (4) the synergic integration of HR activities. Nevertheless, to advance our knowledge in these issues, it seems necessary to integrate previous research in subfunctional, strategic and international aspects of HRM.     

ICT,young people and social work: distances and opportunities

ABSTRACT

The relationship between social work and Information and Communication Technologies (ICTs) is an awkward one in Spanish tradition, particularly from social work perspective due to a certain lack of institutional and professional competence in terms of understanding the capabilities of ICTs. Young people use ICTs to connect to each other and express themselves, however. ICTs represent a means—increasingly the main one—for young people to build and communicate their own identities and understand reality. As with other social sciences, social work suffers from a difficult relationship with young people. Youth is often studied differently and sometimes perceived as a problem that ends when adulthood is reached. In this context, the relationship among ICTs, social work and young people is also a difficult one. But this problem may also be a solution. By adopting a critical ICT approach, social work can create innovative initiatives and frameworks to improve communication between social work practitioners and teachers as with young people and students. Imagination and empathy will clearly be key to achieving this, in addition to deeper involvement in the use of new software and applications that can offer enhanced communication and build bridges between social workers and young people.     

Transformational leadership and job satisfaction of police officers (carabineros) in Chile: the mediating effects of group identification and work engagement / Liderazgo transformacional y satisfacción laboral en carabineros de Chile: los efectos mediadores de la identificación con el grupo y el work engagement

Abstract

The aim of this paper is to examine the relationship between transformational leadership and work satisfaction, as well as to analyse the mediating role of group identification and work engagement in a police training process at a Chilean professional military institution. The sample was made up of 985 candidates representing all the candidates that joined the units of the country in the different locations. Officers and non-commissioned officers acting as instructors were considered ‘leaders’, while their ‘followers’ were the young candidates in the training period. It was found that all the relevant variables were positively and significantly interrelated, and a model of structural equations revealed that both work engagement and group identification played a mediating role in the relationship between transformational leadership and work satisfaction.     

Social Security in Italy

The United States is confronting two simultaneous demographic shifts with profound implications for public policy: population aging and increasing diversity. These changes are accelerating during a dramatic economic downturn, placing entitlement reform prominently on the national policy agenda. Using decennial census data from 2000, this paper examines the nexus of these trends by examining characteristics of Latino baby boomers. In the census data, Latinos constituted 10% of the 80 million boomers; roughly one-third of Latino boomers (37%) were born in the United States or abroad to a U.S. parent; 6% were born in a U.S. territory; 21% were naturalized citizens; and 36% were noncitizens. Compared to non-Latinos, Latino baby boomers had lower levels of education, home ownership, and investment income and higher rates of material hardship and poverty; however, there was considerable variation based on citizenship status. A better understanding of Latino baby boomers will help policy makers anticipate the retirement needs of baby boomers as the United States prepares for the aging of a racially and ethnically diverse population.     

Comparative assessment of analytical approaches to quantify the risk for introduction of rare animal diseases: the example of avian influenza in Spain

Trade of animals and animal products imposes an uncertain and variable risk for exotic animal diseases introduction into importing countries. Risk analysis provides importing countries with an objective, transparent, and internationally accepted method for assessing that risk. Over the last decades, European Union countries have conducted probabilistic risk assessments quite frequently to quantify the risk for rare animal diseases introduction into their territories. Most probabilistic animal health risk assessments have been typically classified into one-level and multilevel binomial models. One-level models are more simple than multilevel models because they assume that animals or products originate from one single population. However, it is unknown whether such simplification may result in substantially different results compared to those obtained through the use of multilevel models. Here, data used on a probabilistic multilevel binomial model formulated to assess the risk for highly pathogenic avian influenza introduction into Spain were reanalyzed using a one-level binomial model and their outcomes were compared. An alternative ordinal model is also proposed here, which makes use of simpler assumptions and less information compared to those required by traditional one-level and multilevel approaches. Results suggest that, at least under certain circumstances, results of the one-level and ordinal approaches are similar to those obtained using multilevel models. Consequently, we argue that, when data are insufficient to run traditional probabilistic models, the ordinal approach presented here may be a suitable alternative to rank exporting countries in terms of the risk that they impose for the spread of rare animal diseases into disease-free countries.     

Risk ranking of food categories associated with Salmonella enterica contamination in the central region of Mexico

To prevent and control foodborne diseases, there is a fundamental need to identify the foods that are most likely to cause illness. The goal of this study was to rank 25 commonly consumed food products associated with Salmonella enterica contamination in the Central Region of Mexico. A multicriteria decision analysis (MCDA) framework was developed to obtain an S. enterica risk score for each food product based on four criteria: probability of exposure to S. enterica through domestic food consumption (Se); S. enterica growth potential during home storage (Sg); per capita consumption (Pcc); and food attribution of S. enterica outbreak (So). Risk scores were calculated by the equation Se*W₁+Sg*W₂+Pcc*W₃+So*W₄, where each criterion was assigned a normalized value (1–5) and the relative weights (W) were defined by 22 experts’ opinion. Se had the largest effect on the risk score being the criterion with the highest weight (35%; IC95% 20%–60%), followed by So (24%; 5%–50%), Sg (23%; 10%–40%), and Pcc (18%; 10%–35%). The results identified chicken (4.4 ± 0.6), pork (4.2 ± 0.6), and beef (4.2 ± 0.5) as the highest risk foods, followed by seed fruits (3.6 ± 0.5), tropical fruits (3.4 ± 0.4), and dried fruits and nuts (3.4 ± 0.5), while the food products with the lowest risk were yogurt (2.1 ± 0.3), chorizo (2.1 ± 0.4), and cream (2.0 ± 0.3). Approaches with expert-based weighting and equal weighting showed good correlation (R² = 0.96) and did not show significant differences among the ranking order in the top 20 tier. This study can help risk managers select interventions and develop targeted surveillance programs against S. enterica in high-risk food products.