Marginal models for the association structure of hierarchical binary responses

Clustered binary responses are often found in ecological studies. Data analysis may include modeling the marginal probability response. However, when the association is the main scientific focus, modeling the correlation structure between pairs of responses is the key part of the analysis. Second-order generalized estimating equations (GEE) are established in the literature. Some of them are more efficient in computational terms, especially facing large clusters. Alternating logistic regression (ALR) and orthogonalized residual (ORTH) GEE methods are presented and compared in this paper. Simulation results show a slightly superiority of ALR over ORTH. Marginal probabilities and odds ratios are also estimated and compared in a real ecological study involving a three-level hierarchical clustering. ALR and ORTH models are useful for modeling complex association structure with large cluster sizes.     

Psychodynamic Couple Therapy: A Practical Synthesis

This essay reviews the most significant contributions of psychodynamic thought to the field of couple therapy. It distills the work of numerous clinicians and researchers who, though writing from diverse perspectives, share fundamental assumptions and concerns. Rather than emphasizing differences between schools of thought, this paper mines their best contributions in a discussion of five central therapeutic targets: underlying issues, divergent subjective experiences, transferences, projective identification, and acceptance. Two detailed cases illustrate the benefits and techniques for targeting these five therapeutic domains. Video Abstract is found in the online version of the article .     

Conceptualising and Measuring Social Cohesion in Africa: Towards a Perceptions-Based Index

Social cohesion is a key concept in development studies. Weak social cohesion is often related to slow economic growth and (violent) conflict. So far few attempts have been made to measure this complex concept in a systematic manner. This paper introduces an innovative method to measure national-level social cohesion based on survey data from 19 African countries. We distinguish three dimensions of social cohesion; i.e. the extent of perceived inequalities, the level of societal trust, and the strength of people’s adherence to their national identity. Importantly, our Social Cohesion Index (SCI) is based on individuals’ perceptions vis-à-vis these three different dimensions of social cohesion rather than certain macro-level ‘objective’ indicators such as GDP/capita or Gini-coefficients. We develop two social cohesion indices: a national average SCI and a Social Cohesion Index Variance-Adjusted (SCIVA); the latter one takes into account the level of variation across different ethnic groups within countries. The SCI and SCIVA are computed for and compared across nineteen African countries for the period 2005–2012 on the basis of Afrobarometer survey rounds 3, 4 and 5. We also investigate quantitatively the relationship between countries’ levels of social cohesion and the occurrence of a range of conflict events. As expected, we find that countries with low levels of social cohesion in a particular year according to our SCI are more likely to experience a range of different violent conflict events in the subsequent year.     

Usability in product design--the importance and need for systematic assessment models in product development--Usa-Design Model (U-D) ©

In product design, human factors are considered as an element of differentiation given that today's consumer demands are increasing. Safety, wellbeing, satisfaction, health, effectiveness, efficiency, and other aspects must be effectively incorporated into the product development process. This work proposes a usability assessment model that can be incorporated as an assessment tool. The methodological approach is settled in two stages. First a literature review focus specifically on usability and developing user-centred products. After this, a model of usability named Usa-Design (U-D?) is presented. Consisted of four phases: understanding the use context, pre-preliminary usability assessment (efficiency/effectiveness/satisfaction); assessment of usability principles and results, U-D? features are modular and flexible, allowing principles used in Phase 3 to be changed according to the needs and scenario of each situation. With qualitative/quantitative measurement scales of easy understanding and application, the model results are viable and applicable throughout all the product development process.     

Work hours,social value of leisure and globalisation

We examine how openness interacts with the coordination of consumption–leisure decisions in determining the equilibrium working hours and wage rate when there are leisure externalities (e.g., due to social interactions). The latter are modelled by allowing a worker's marginal utility of leisure to be increasing in the leisure time taken by other workers. Coordination takes the form of internalising the leisure externality and other relevant constraints (e.g., labour demand). The extent of openness is measured by the degree of capital mobility. We find that: coordination lowers equilibrium work hours and raises the wage rate; there is a U-shaped (inverse-U-shaped) relationship between work hours (wages) and the degree of coordination; coordination is welfare improving; and, the gap between the coordinated and uncoordinated work hours (and the corresponding wage rates) is affected by the extent and nature of openness.     

Species richness in urban parks and its drivers: A review of empirical evidence

There is growing recognition of urban areas as hosts for innovative ways to conserve and promote biodiversity. Parks, as one specific type of urban green space, constitute particularly important biodiversity hotspots in the cityscape. We reviewed empirical findings on the species richness in urban parks across all species groups that have been studied. The aim was to assess and discuss the overall species richness of urban parks, its community attributes and drivers. Search and subsequent selection process resulted in 62 papers from 25 different countries. For all examined species groups, the findings consistently show that parks are among the most species rich types of urban green spaces, but also that exotics constitute large shares, especially of plant species. Key ecological theories like the gradient approach and the island habitat ecological theory, and fundamental ecological relationships such as the species-area relationship are valid despite the manipulated ‘nature’ of parks and the surrounding urban matrix. Most studies surveyed large number of parks and applied ‘multi-scale’ approaches in tests of confounding variables, providing methodological strength. While matrix effects are consistently found to affect species richness negatively, the diversity of habitats and microhabitat heterogeneity contained in urban parks appears as the most decisive factor for the overall species richness. However, a constraint of research to date is the limitation of individual studies to one or a few species groups, rarely bridging between flora and fauna. Adopting ‘multi-species group’ approaches in future research is needed to further advance the understanding of the overall biodiversity of urban parks, and its drivers.     

Empowered and self-managing users in methadone treatment?

Empowerment is a keyword in treatment. Users should have the means and possibilities to influence their treatment and become self-managing. Drawing on ethnographic fieldwork in a Danish methadone treatment project, we find that the practices of users and staff are often not carried out in accordance with governmental intentions. We identify a gap between the official notions of treatment and practices. We analyse the notions and practices of empowerment by applying two analytical perspectives. First, we apply a constructionist perspective in which empowerment is analysed as wanting to set users ‘free’ but also as ways to govern. We elaborate the analysis by applying a more practice-oriented focus. Drawing on this perspective, we analyse the ways in which staff and users constantly produce, construct and negotiate institutional practices that differ from the governmental intentions for treatment.     

The competing risks analysis for parallel and series systems using Type-II progressive censoring

Abstract

Recently, the study of the lifetime of systems in reliability and survival analysis in the presence of several causes of failure (competing risks) has attracted attention in the literature. In this paper, series and parallel systems with exponential lifetime for each item of the system are considered. Several causes of failure independently affect lifetime distributions and observations of failure times of the systems are considered under progressive Type-II censored scheme. For series systems, the maximum likelihood estimates of parameters are computed and confidence intervals for parameters of the model are obtained using Fisher information matrix. For parallel systems, the generalized EM algorithm which uses the Newton-Raphson algorithm inside the EM algorithm is used to compute the maximum likelihood estimates of parameters. Also, the standard errors of the maximum likelihood estimates are computed by using the supplemented EM algorithm. The simulation study confirms the good performance of the introduced approach.     

Reduction in Dietary Acrylamide Exposure—Impact of Potatoes with Low Acrylamide Potential

Acrylamide forms primarily from a reaction between reducing sugars (e.g., glucose and fructose) and an amino acid (asparagine, Asn) formed naturally in foods, including potatoes. This reaction occurs when carbohydrate‐rich foods are heated at temperatures above 120 °C. Multiple potato varieties were transformed with potato genomic DNA that results in down‐regulation of the expression of the asparagine synthetase‐1 gene (Asn1), significantly reducing synthesis of free Asn, and consequently lowering the potential to form acrylamide during cooking. These potatoes with low acrylamide potential (LAP) were tested in agronomic trials, and processed into French fries and potato chips. Decreased levels of acrylamide were measured in these cooked food products when derived from LAP potatoes compared with those derived from conventional potatoes. These reductions can be directly attributed to reduction in Asn levels in the LAP potatoes. The corresponding average reduction in exposure to acrylamide from French fry and potato chip consumption is estimated to be 65%, which would amount to approximately a 25% reduction in overall dietary exposure. Considering that children consume nearly three times more acrylamide than adults on a per kg body weight basis, they would experience the most impact from the reduced acrylamide associated with LAP potatoes. The potential public health impacts, in context of dietary acrylamide exposure reduction, are discussed in this study.     

The impact of a workplace terrorist attack on employees' perceptions of leadership: A longitudinal study from pre- to postdisaster

A terrorist attack targeting a workplace represents an organizational crisis that requires the leaders to manage emerging threats. The changing roles and expectations of the leaders are reflected in the employees' perceptions of them over time. The purpose of this study was to determine whether the 2011 Oslo bombing attack affected the targeted employees' perceptions of the leadership behaviors of their immediate superiors or the organizational managers' interest in the health and well-being of their workers. Ministerial employees (n ≈ 180) completed questionnaires on fair, empowering, and supportive leadership, in addition to human resource primacy, on two occasions several years prior to the terrorist attack. Assessments were then repeated one, two, and three years after the attack. Changes in the course of perceived leadership from predisaster to postdisaster were examined using bootstrapped t-tests and latent growth curve models. Furthermore, the general course of perceived leadership was compared with a nonexposed control sample of matched employees. Results showed that employees with high levels of posttraumatic stress perceived their immediate leader to be less supportive. However, overall perceptions of leadership were remarkably stable, which suggests that the effects of critical incidents on perceptions of leadership may be negligible.