Cut-points to prevent low back injury due to force exertion at work

Force exertion is related to low back injuries (LBI). This paper critically reviews the literature concerning cut-points for back force exertion, presents available guidelines in a concise manner, and identifies areas that need further research. The studies reviewed were grouped according to the criteria used to set the cut-point values. Most often cut-points differ than concur. The approach considering physiological, psychophysical, epidemiological, and biomechanical aspects of back force exertion meets the most known criteria and presents the lowest common denominator of instantaneous load for lifting tasks. Further experimental and epidemiological studies in peak load and cumulative exposure are necessary. Compound indices should also be developed for pushing, pulling, and carrying. Future indices should consider electromyographically determined fatigue, differential viscoelastic properties of tissues, aging, and the cross sectional area of back muscles. We hope that this paper contributes to a more systematic appraisal of back force exertion at work.     

Participation of seniors in the Argentinian labour market: An option value model*

The aim of this article is to define the factors which determine seniors' decisions to continue to participate in the labour market in Argentina. An option value model is developed. This model is used to produce estimates based on micro‐data drawn from household surveys. These indicate the relative importance of the impact of conditions governing eligibility for benefits on decisions to remain actively employed. Work history is found to be the main factor in such decisions. Inadequacy of social security benefits and accumulated human capital also create incentives for economic participation in old age. On the basis of these findings, compensatory policy adjustments, to improve coverage, increase benefit levels and improve employment conditions for seniors, are proposed.     

Sensitivity analysis and choosing between alternative polytomous IRT models using Bayesian model comparison criteria

Polytomous Item Response Theory (IRT) models are used by specialists to score assessments and questionnaires that have items with multiple response categories. In this article, we study the performance of five model comparison criteria for comparing fit of the graded response and generalized partial credit models using the same dataset when the choice between the two is unclear. Simulation study is conducted to analyze the sensitivity of priors and compare the performance of the criteria using the No-U-Turn Sampler algorithm, under a Bayesian approach. The results were used to select a model for an application in mental health data.     

Correction to: Comparison of joint control schemes for multivariate normal i.i.d. output

AStA Advances in Statistical Analysis - In the original paper, we incorrectly stated that...     

Topiramate Combined with Cognitive Restructuring for the Treatment of Gambling Disorder: A Two-Center,Randomized, Double-Blind Clinical Trial

Gambling disorder (GD) is a prevalent condition for which no pharmacological treatment has yet been approved, although there is evidence that topiramate can reduce impulsivity in GD and craving in various addictive behaviors. The goal of this study was to investigate the effectiveness of topiramate combined with cognitive restructuring for GD in a two-center, randomized, double-blind clinical trial. Participants were individuals seeking outpatient treatment for GD (n = 30), treated with either topiramate or placebo combined with a brief cognitive intervention, over a 12-week period, the dose of topiramate being tapered up during the first 8 weeks. The main outcome measures were gambling craving, behavior, and cognitive distortions; impulsivity; depression and social adjustment. Topiramate proved superior to placebo in reducing gambling craving (P = 0.017); time and money spent gambling (P = 0.007 and P = 0.047, respectively); cognitive distortions related to gambling (P = 0.003); and social adjustment (P = 0.040). We found no significant effects on impulsivity or depression. These findings are in contrast with data from a previous clinical trial with topiramate for GD. In the current study, we found that topiramate affects features specifically related to gambling addiction and had no significant effect on associated phenomena such as impulsiveness and depression. We believe that this response could be due to synergistic interaction between topiramate and the cognitive intervention.     

Bayesian analysis of the generalized gamma distribution using non-informative priors

The Generalized gamma (GG) distribution plays an important role in statistical analysis. For this distribution, we derive non-informative priors using formal rules, such as Jeffreys prior, maximal data information prior and reference priors. We have shown that these most popular formal rules with natural ordering of parameters, lead to priors with improper posteriors. This problem is overcome by considering a prior averaging approach discussed in Berger et al. [Overall objective priors. Bayesian Analysis. 2015;10(1):189–221]. The obtained hybrid Jeffreys-reference prior is invariant under one-to-one transformations and yields a proper posterior distribution. We obtained good frequentist properties of the proposed prior using a detailed simulation study. Finally, an analysis of the maximum annual discharge of the river Rhine at Lobith is presented.     

An evaluation of common methods for dichotomization of continuous variables to discriminate disease status

Dichotomization of continuous variables to discriminate a dichotomous outcome is often useful in statistical applications. If a true threshold for a continuous variable exists, the challenge is identifying it. This paper examines common methods for dichotomization to identify which ones recover a true threshold. We provide mathematical and numeric proofs demonstrating that maximizing the odds ratio, Youden’s statistic, Gini Index, chi-square statistic, relative risk and kappa statistic all theoretically recover a true threshold. A simulation study evaluating the ability of these statistics to recover a threshold when sampling from a population indicates that maximizing the chi-square statistic and Gini Index have the smallest bias and variability when the probability of being larger than the threshold is small while maximizing Kappa or Youden’s statistics is best when this probability is larger. Maximizing odds ratio is the most variable and biased of the methods.     

A generalised NGINAR(1) process with inflated‐parameter geometric counting series

In this paper we propose a new stationary first‐order non‐negative integer valued autoregressive process with geometric marginals based on a generalised version of the negative binomial thinning operator. In this manner we obtain another process that we refer to as a generalised stationary integer‐valued autoregressive process of the first order with geometric marginals. This new process will enable one to tackle the problem of overdispersion inherent in the analysis of integer‐valued time series data, and contains the new geometric process as a particular case. In addition various properties of the new process, such as conditional distribution, autocorrelation structure and innovation structure, are derived. We discuss conditional maximum likelihood estimation of the model parameters. We evaluate the performance of the conditional maximum likelihood estimators by a Monte Carlo study. The proposed process is fitted to time series of number of weekly sales (economics) and weekly number of syphilis cases (medicine) illustrating its capabilities in challenging cases of highly overdispersed count data.     

Behavioral economics and the economics of Keynes

The aim of this paper is two-fold: it first evaluates some of the psychological insights offered by Keynes in his economic theories, and secondly it weighs up these insights in the light of recent research in behavioral and experimental economics. We found that many of the psychological ideas set forth by Keynes in his economic works, especially in The General Theory, have a defensible behavioral foundation and fit broadly the actual behavior of economic agents in the real world as suggested by recent empirical evidence. As a consequence, we argue that Keynesian economics can benefit from this interaction, especially for issues related to judgment under uncertainty and building solid microfoundations for macroeconomics.     

The deaf and the classroom design: a contribution of the built environmental ergonomics for the accessibility

In any concept of school design, classroom occupies the central place. Dimensions, lighting, the equipment needed, ventilation are old questions already answered, even in form of laws and standards adopted. However, the best use of available materials and physical conditions of comfort is not sufficient for a classroom design guaranteed success. The classroom should provide deaf students elements to facilitate the learning process, eliminating as much as possible the obstacles created by lack of hearing and allowing them to have the same access to learning as a listener student. As users of a school building, teachers, students, parents and staff are the best evaluators of the physical environment of schools. The environmental comfort is a largest ally of pedagogy. The learning comes from the perception and the concentration of students in the classroom. The purpose of this study is to detect the role of direct perception (physical) and indirect (intangible) elements that informs and have symbolic value, and propose layouts for accessible classrooms to deaf students. The ergonomics of the built environment evaluation methods could use the participatory design method tools as basis to assessing how users perceive and use the school environment.