Three Approaches to Understanding Self-Help Groups

With the increasing importance of self-help groups, professionals need to augment their understanding of how groups work in order to help clients make effective use of them. Three conceptual frameworks-social networks, social learning and cognitive theory-explain the basic psychosocial processes of self-help groups. Practice implications indicate how clients can benefit from self-help groups and suggest how professionals might enable their clients to realize the full benefits of participation in them.     

Psychologically and biochemically assessed stress in a follow-up study of long-term unemployed

Abstract

It has been suggested that psychological stress is one of the reasons for the high morbidity among unemployed people in Western countries. The same may apply to the well-documented high mortality. It would be expected that increased levels of biological stress would be found in these people. In the present study a sample of 310 long-term unemployed people from Norway was followed for 2 years. Psychologcal stress was assessed by medical examination and by the psychometric tests GHQ-28 and HSCL-30, the latter compared with a reference population of employed people. Serum levels of cortisol, prolactin and testosterone, together with immunoglobulins IgA, IgG and IgM, were compared with working controls. The unemployed had a high level of psychological distress at the first examination, the sanie for men and women. At the 2-year follow up distress was reduced by re-employment. This fits the ‘causation hypothesis' which explains the high distress level as caused by unemployment. The other direction of causation, ‘the selection hypothesis', assuming that distressed persons have an increased chance of continuous unemployment, was also confirmed in the present study. As for biological stress, significant differences were not found between the unemployment, the re-employed and the working controls.     

Measurement of the subjective work environment

Abstract

This paper considers the various issues that frame the development and use of measures of the subjective work environment. It begins by questioning the role of the work environment in determining occupational health, and explores the possible mechanisms by which that environment might exert its influence. It concludes that one of the important final common pathways is psycho-physiological in nature, and is rooted in individual perception and cognition and the experience of stress. Important for this model are the concepts of mediation and moderation. The measurement of the subjective work environment has often been idiosyncratic to the study in hand, and there are few well-established measures in common use. It is argued that researchers should be careful when deciding not to use established measures and effectively ‘invent’ their own. In developing new measures, decisions have to be made concerning the nature of the measure along with its ‘granularity’ and complexity. It is also argued that it is important that researchers should follow good psychometric practice in the development of those measures. Suggestions for ‘good practice’ are discussed. Attention is drawn to the issues of reliability and validity, and this paper discusses the role of triangulation in the planning and execution of data collection and analysis. The paper ends by reviewing the recommendations made towards the development and use of measures of the subjective work environment.     

Influence of Late Life Stressors on the Decisions of Older Women to Relocate into Congregate Senior Housing

Late-life stressors often require individuals to make substantial alterations in behavior and lifestyle and can affect their overall health and well-being. Relocation is a significant life stress, regardless of age. The primary aim of this study is to elucidate the push-pull factors associated with moving into congregate senior housing. The secondary aim is to investigate the decision-making processes and stresses associated with moving into a congregate living environment. Interviews were conducted with 26 women who were new residents in congregate senior housing. Relocation, as expected, was considered to be stressful, although individual differences were found among perceptions of relocation stresses. Women who had made the decision to relocate on their own showed evidence of better psychosocial well-being at the time of the move. One-quarter of the sample chose to move to provide care to another person. As the options for senior housing continue to evolve and the number of adults reaching advanced age continues to increase, it is important to understand the factors that contribute to successful adaptation. This knowledge will enable facility administrators to implement programs and procedures to assist incoming residents with acclimating to their new homes.     

Usability Study of a Distance Continuing Education Website for Human Service Professionals

ABSTRACT

A usability test of a distance continuing education website for human service professionals is discussed. The website's purpose was to help meet the continuing education needs of human service professionals in a largely rural Midwestern state. The purpose of the usability evaluation was to assess the website's ease of use, efficiency, and user satisfaction in a representative sample of human service professionals. Users completed eleven basic search tasks with the site and report their impressions of the information presented. In addition, performance data including success, time on task, and efficiency were gathered. Implications of user satisfaction and performance data highlight the importance of stakeholder's involvement in the early stages of website design.     

Testing the Granger Noncausality Hypothesis in Stationary Nonlinear Models of Unknown Functional Form

In this article, we propose a general method for testing the Granger noncausality hypothesis in stationary nonlinear models of unknown functional form. These tests are based on a Taylor expansion of the nonlinear model around a given point in the sample space. We study the performance of our tests by a Monte Carlo experiment and compare these to the most widely used linear test. Our tests appear to be well-sized and have reasonably good power properties.     

Implementing Monte Carlo tests with p-value buckets

Software packages usually report the results of statistical tests using p-values. Users often interpret these values by comparing them with standard thresholds, for example, 0.1, 1, and 5%, which is sometimes reinforced by a star rating (***, **, and *, respectively). We consider an arbitrary statistical test whose p-value p is not available explicitly, but can be approximated by Monte Carlo samples, for example, by bootstrap or permutation tests. The standard implementation of such tests usually draws a fixed number of samples to approximate p. However, the probability that the exact and the approximated p-value lie on different sides of a threshold (the resampling risk) can be high, particularly for p-values close to a threshold. We present a method to overcome this. We consider a finite set of user-specified intervals that cover [0, 1] and that can be overlapping. We call these p-value buckets. We present algorithms that, with arbitrarily high probability, return a p-value bucket containing p. We prove that for both a bounded resampling risk and a finite runtime, overlapping buckets need to be employed, and that our methods both bound the resampling risk and guarantee a finite runtime for such overlapping buckets. To interpret decisions with overlapping buckets, we propose an extension of the star rating system. We demonstrate that our methods are suitable for use in standard software, including for low p-value thresholds occurring in multiple testing settings, and that they can be computationally more efficient than standard implementations.     

食品检测咀嚼机器人工作空间研究

为了提高食品检测效率,改善食品检测精度,增加食品检测的客观性,文章介绍了一种基于6-UPS机构的咀嚼机器人,介绍了咀嚼机器人的结构原理,求解了机构的运动学逆解,分析了机构的工作空间影响因素,利用MATLAB编程求得机构在定姿态下的工作空间。空间轮廓图表明,该机构在定姿态下能到达人类全部真实咀嚼空间,机构设计可靠,能够模拟人类咀嚼行为对食品进行检测。     

A Rejection Principle for Sequential Tests of Multiple Hypotheses Controlling Familywise Error Rates

We present a unifying approach to multiple testing procedures for sequential (or streaming) data by giving sufficient conditions for a sequential multiple testing procedure to control the familywise error rate (FWER). Together, we call these conditions a ‘rejection principle for sequential tests’, which we then apply to some existing sequential multiple testing procedures to give simplified understanding of their FWER control. Next, the principle is applied to derive two new sequential multiple testing procedures with provable FWER control, one for testing hypotheses in order and another for closed testing. Examples of these new procedures are given by applying them to a chromosome aberration data set and finding the maximum safe dose of a treatment.     

An F-type test for detecting departure from monotonicity in a functional linear model

When studying associations between a functional covariate and scalar response using a functional linear model (FLM), scientific knowledge may indicate possible monotonicity of the unknown parameter curve. In this context, we propose an F-type test of monotonicity, based on a full versus reduced nested model structure, where the reduced model with monotonically constrained parameter curve is nested within an unconstrained FLM. For estimation under the unconstrained FLM, we consider two approaches: penalised least-squares and linear mixed model effects estimation. We use a smooth then monotonise approach to estimate the reduced model, within the null space of monotone parameter curves. A bootstrap procedure is used to simulate the null distribution of the test statistic. We present a simulation study of the power of the proposed test, and illustrate the test using data from a head and neck cancer study.