On the estimation of the most probable number in a serial dilution experiment

The purpose of this paper is to present some alternative estimates for the 'most probable number' of bacteria in a serial dilution experiment. These estimates are directed to be less biased than the ordinary maximum likelihood estimate. A numerical example illustrates the extent to which the variance and the mean square error of these estimates are generally less than those corresponding to the maximum likelihood estimate.     

On the hyper-dirichlet type 1 and hyper-liouville distributions

This paper concerns the characterization of a new family of multivariate beta distribution functions - the hyper-Dirichlet type 1 distribution. This family describes the joint density function of the terminal variates of an arbitrary tree constructed from finite sequences of probability vectors having independent Dirichlet type 1 distributions. Expressions for the general properties of the hyper-Dirichlet type 1 distribution are presented. In addition, the hyper-Liouville distribution is described and its properties are discussed as well as a generalization of the Liouville integral identity.     

The Meaningful Roles Intervention: An Evolutionary Approach to Reducing Bullying and Increasing Prosocial Behavior

Bullying is a problem that affects adolescents worldwide. Efforts to prevent bullying have been moderately successful at best, or iatrogenic at worst. We offer an explanation for this limited success by employing an evolutionary‐psychological perspective to analyze antibullying interventions. We argue that bullying is a goal‐directed behavior that is sensitive to benefits as well as costs, and that interventions must address these benefits. This perspective led us to develop a novel antibullying intervention, Meaningful Roles, which offers bullies prosocial alternatives—meaningful roles and responsibilities implemented through a school jobs program and reinforced through peer‐to‐peer praise notes—that effectively meet the same status goals as bullying behavior. We describe this new intervention and how its theoretical evolutionary roots may be applicable to other intervention programs.     

The Interplay Between Employee and Firm Customer Orientation: Substitution Effect and the Contingency Role of Performance‐Related Rewards

This paper identifies and explains a potential tension between a firm's emphasis on customer orientation (CO) and the extent to which employees value CO as a success factor for individual performance. Based on self‐determination theory and CO implementation research, the authors propose that firm CO may represent both autonomous and controlled motivations for CO, but that employees’ CO is more strongly linked to individual performance when employees experience solely autonomous motivation. Hence, the authors expect a substitution effect whereby the link between employees’ CO and their performance is weaker when firm CO is high. Furthermore, the authors examine a boundary condition for the previous hypothesis and propose that performance‐contingent rewards have a positive effect on the internalization of the extrinsic motivation stemming from firm CO. Two multilevel studies with 979 employees and 201 top management team members from 132 firms support these hypotheses. Against previous research, these findings offer a new perspective on the effectiveness of CO initiatives, propose employees’ motivational states as the theoretical explanation for the heterogeneity in the link between employee CO and performance, and reappraise the role of performance‐contingent rewards in CO research. Managerial implications for the effective implementation of customer‐oriented initiatives within firms are provided.     

Collective survival strategies and anti-colonial practice in ecosocial work

ABSTRACT

Oppressed communities have long used strategies of caring for and protecting each other to ensure their collective survival. We argue for ecosocial workers to critically interrogate how agency, history, and culture structure environmental problems and our responses to them, by developing a resilience-based framework, collective survival strategies (CSS). CSS consider power, culture and history and build upon the strengths of oppressed communities facing global environmental changes. We challenge the dominant narrative of climate change as a “new” problem and connect it to colonization. We discuss implications by examining a social work program explicitly built on Indigenous knowledges and anti-colonial practice.     

Listeria monocytogenes Dose Response Revisited—Incorporating Adjustments for Variability in Strain Virulence and Host Susceptibility

Evaluations of Listeria monocytogenes dose‐response relationships are crucially important for risk assessment and risk management, but are complicated by considerable variability across population subgroups and L. monocytogenes strains. Despite difficulties associated with the collection of adequate data from outbreak investigations or sporadic cases, the limitations of currently available animal models, and the inability to conduct human volunteer studies, some of the available data now allow refinements of the well‐established exponential L. monocytogenes dose response to more adequately represent extremely susceptible population subgroups and highly virulent L. monocytogenes strains. Here, a model incorporating adjustments for variability in L. monocytogenes strain virulence and host susceptibility was derived for 11 population subgroups with similar underlying comorbidities using data from multiple sources, including human surveillance and food survey data. In light of the unique inherent properties of L. monocytogenes dose response, a lognormal‐Poisson dose‐response model was chosen, and proved able to reconcile dose‐response relationships developed based on surveillance data with outbreak data. This model was compared to a classical beta‐Poisson dose‐response model, which was insufficiently flexible for modeling the specific case of L. monocytogenes dose‐response relationships, especially in outbreak situations. Overall, the modeling results suggest that most listeriosis cases are linked to the ingestion of food contaminated with medium to high concentrations of L. monocytogenes. While additional data are needed to refine the derived model and to better characterize and quantify the variability in L. monocytogenes strain virulence and individual host susceptibility, the framework derived here represents a promising approach to more adequately characterize the risk of listeriosis in highly susceptible population subgroups.     

LIML in the static linear panel data model

We consider the static linear panel data model with a single regressor. For this model, we derive the LIML estimator. We study the asymptotic behavior of this estimator under many-instruments asymptotics, by showing its consistency, deriving its asymptotic variance, and by presenting an estimator of the asymptotic variance that is consistent under many-instruments asymptotics. We briefly indicate the extension to the static panel data model with multiple regressors.     

Negative Acculturation and Nothing More? Cumulative Disadvantage and Mortality during the Immigrant Adaptation Process among Latinos in the United States

Foreign‐ and U.S.‐born Hispanic health deteriorates with increasing exposure and acculturation to mainstream U.S. society. Because these associations are robust to (static) socioeconomic controls, negative acculturation has become their primary explanation. This overemphasis, however, has neglected important alternative structural explanations. Examining Hispanic mortality using the 1998–2006 U.S. National Health Interview Survey‐Linked Mortality File according to nativity, immigrant adaptation measures, and health behaviors, this study presents indirect but compelling evidence that suggests negative acculturation is not the only or main explanation for this deterioration.     

The Reverse Supply Chain Planning Matrix: A Classification Scheme for Planning Problems in Reverse Logistics

This paper presents a conceptual planning framework for reverse supply chain operations based on an extensive literature review and industry expertise. Such a holistic scheme for classification of planning tasks is necessary as the intensification of research on reverse logistics and closed‐loop supply chains in recent years has raised a number of planning problems that differ from those of solely forward‐oriented supply chains. Up to now, a common and comprehensive definition of relevant planning problems along the reverse chain has not existed. Thus, a thorough understanding of the interdependence between these elements is missing. This paper aims to systematically identify planning problems, which are assigned to different planning horizons and distinct process stages of product recovery. The result is a classification scheme, called a ‘Reverse Supply Chain Planning Matrix’ (RSCPM), which categorizes planning problems and shows their interrelation in recovery operations. It serves both academia and practitioners as a holistic overview for planning and decision tasks. Moreover, decision‐makers are supported in identifying the relevant variables in reverse supply chains and in revealing the consequences of one decision regarding other parameters of the system. To the best of the authors' knowledge, the RSCPM is the first attempt to comprehensively structure the field of reverse supply chain research by identifying, defining and interconnecting planning problems within an integrated framework, as is common in the forward case.