Influence measures based on confidence ellipsoids in general linear regression model with correlated regressors

In this paper, we investigated the Andrews–Pregibon (AP), COVRATIO and Cook–Weisberg (CW) statistics to determine the influential observations on the confidence ellipsoids in linear regression model with correlated errors and correlated regressors. A real example and a Monte Carlo simulation study are given to detect the effects of autocorrelation coefficient and ridge parameter on the AP, COVRATIO and CW statistics.     

Improvising Prescription: Evidence from the Emergency Room

Global medical practice is increasingly standardizing through evidence‐based approaches and quality certification procedures. Despite this increasing standardization, medical work in emergency units necessarily involves sensitivity to the individual, the particular and the unexpected. While much medical practice is routine, important improvisational elements remain significant. Standardization and improvisation can be seen as two conflicting logics. However, they are not incompatible, although the occurrence of improvisation in highly structured and institutionally complex environments remains underexplored. The study presents the process of improvisation in the tightly controlled work environment of the emergency room. The authors conducted an in situ ethnographic observation of an emergency unit. An inductive approach shows professionals combining ostensive compliance with protocols with necessary and occasional ‘underlife’ improvisations. The duality of improvisation as simultaneously present and absent is related to pressures in the institutional domain as well as to practical needs emerging from the operational realm. The intense presence of procedures and work processes enables flexible improvised performances that paradoxically end up reinforcing institutional pressures for standardization.     

Social work and macro-economic neoliberalism: beyond the social justice rhetoric

Macro-economic policy shapes and structures social welfare policy, services, and their implementation. As a result, the commoditisation of social welfare services and the use of markets as well as private sector management philosophies and tools have colonised and fashioned the design, provision and implementation of social welfare policy and structures. The impact has been far reaching, from limiting social welfare responses of elected democratic government to shaping the profession in a range of intended and unintended directions. Written from a UK perspective, this paper proposes a discussion of the impact of macro-economic neoliberal policies in the field of social welfare and explores the implications for social work practice. The paper also promotes a debate within the profession regarding the importance of macro-economic analysis and possible responses, as well as suggesting a way forward within European and, more broadly, international practice contexts.     

Modeling initiation into drug injection among street youth

This study aimed at examining the predictors of initiation into drug injection among street youth using social cognitive theory framework. A prospective cohort study based on semi-annual interviews was carried out. Psychosocial determinants referred to avoidance of initiation. Other potential predictors were: sociodemographic characteristics, relationships with injectors, parent's substance misuse, drug use patterns, homelessness, survival sex, sexual abuse. Independent predictors were identified using Cox proportional hazards regression models. Among the 352 participants, high control beliefs about avoidance of initiation was protective while younger age, daily alcohol consumption, heroin use, cocaine use, and survival sex all increased risk of initiation. Preventive strategies targeting street youth should both enhance youth's control beliefs and actual control over their substance use and improve their life conditions.     

Metropolis–Hastings algorithms with adaptive proposals

Different strategies have been proposed to improve mixing and convergence properties of Markov Chain Monte Carlo algorithms. These are mainly concerned with customizing the proposal density in the Metropolis–Hastings algorithm to the specific target density and require a detailed exploratory analysis of the stationary distribution and/or some preliminary experiments to determine an efficient proposal. Various Metropolis–Hastings algorithms have been suggested that make use of previously sampled states in defining an adaptive proposal density. Here we propose a general class of adaptive Metropolis–Hastings algorithms based on Metropolis–Hastings-within-Gibbs sampling. For the case of a one-dimensional target distribution, we present two novel algorithms using mixtures of triangular and trapezoidal densities. These can also be seen as improved versions of the all-purpose adaptive rejection Metropolis sampling (ARMS) algorithm to sample from non-logconcave univariate densities. Using various different examples, we demonstrate their properties and efficiencies and point out their advantages over ARMS and other adaptive alternatives such as the Normal Kernel Coupler.     

Gender Differences in Time Availability: Evidence from France

The aim of the article is to examine differences in work time from a gender perspective. To this end, a concept broader than mere duration of work time is constructed. This concept, which we call time availability, encompasses not only the volume of hours worked but also the scheduling and predictability of those hours. It is measured by a synthetic indicator showing the extent to which a given group of workers exceeds the societal time norm. After a presentation of the French context, we show that women seem to have less time availability, particularly at the ages that are most decisive in career terms. But these differences do not concern the same aspects of time availability. Thus the time constraints experienced mainly by women are less socially visible and hence undervalued by employers. This lower visibility comes, for a large part, from the social perception of women professionals.     

Feasible Mechanisms in Economies with Type-Dependent Endowments

We propose two classes of allocation games for N.T.U. and T.U. exchange economies in which initial endowments and preferences depend on the agents’ private information. In both models, agents make non-verifiable claims about their types and effective deposits of consumption goods, which are redistributed by the planner. In a W-allocation game, the agents can withhold part of their endowment, namely consume whatever they do not deposit. In a D-allocation game, the agents can just destroypart of their endowment. W- and D- incentive compatible (I.C.) direct allocation mechanisms ask every agent to reveal his type and to make a deposit consistent with his reported type. The revelation principle holds in full generality for D-I.C. mechanisms but some care is needed for W-I.C. mechanisms. We further investigate the properties of both classes of mechanisms under common assumptions like non-exclusive information and/or constant aggregate endowment. In T.U. economies, W-I.C. and D-I.C. mechanisms are ex ante equivalent.     

Leaving Home in Europe: The Role of Parents’ and Children’s Incomes

This paper examines the role of parents’ and children’s incomes in the ‘leaving home’ decisions of young adults in Europe. Using the ECHP data on 11 European countries, results from random and fixed-effects models suggest that the leaving home decision is positively related to the child’s income. The effect of parents’ income is less clear and of lower magnitude. These patterns are broadly similar among European countries, in spite of significant differences in the institutional contexts.     

Smoothed functional canonical correlation analysis of humidity and temperature data

This paper focuses on smoothed functional canonical correlation analysis (SFCCA) to investigate the relationships and changes in large, seasonal and long-term data sets. The aim of this study is to introduce a guideline for SFCCA for functional data and to give some insights on the fine tuning of the methodology for long-term periodical data. The guidelines are applied on temperature and humidity data for 11 years between 2000 and 2010 and the results are interpreted. Seasonal changes or periodical shifts are visually studied by yearly comparisons. The effects of the ‘number of basis functions’ and the ‘selection of smoothing parameter’ on the general variability structure and on correlations between the curves are examined. It is concluded that the number of time points (knots), number of basis functions and the time span of evaluation (monthly, daily, etc.) should all be chosen harmoniously. It is found that changing the smoothing parameter does not have a significant effect on the structure of curves and correlations. The number of basis functions is found to be the main effector on both individual and correlation weight functions.