Physical exercise,employee fitness and the management of health at work

Abstract

This paper presents some recent data on why organizations invest in exercise and physical fitness programmes for their stiff. These data suggest that, owing to a lack of evaluation studies, organizations act mainly on the basis of assumption and belief. However, from a subsequent review of the available literature on the personal and organizational effects of such programmes, it appears that these assumptions and beliefs are not altogether unfounded. The paper concludes by discussing the ways in which exercise and employee fitness programmes might help die individual and their organization in terms of the management of health at work.     

Pool‐Point Distribution of Zero‐Inventory Products

We study zero‐inventory production‐distribution systems under pool‐point delivery. The zero‐inventory production and distribution paradigm is supported in a variety of industries in which a product cannot be inventoried because of its short shelf life. The advantages of pool‐point (or hub‐and‐spoke) distribution, explored extensively in the literature, include the efficient use of transportation resources and effective day‐to‐day management of operations. The setting of our analysis is as follows: A production facility (plant) with a finite production rate distributes its single product, which cannot be inventoried, to several pool points. Each pool point may require multiple truckloads to satisfy its customers' demand. A third‐party logistics provider then transports the product to individual customers surrounding each pool point. The production rate can be increased up to a certain limit by incurring additional cost. The delivery of the product is done by identical trucks, each having limited capacity and non‐negligible traveling time between the plant and the pool points. Our objective is to coordinate the production and transportation operations so that the total cost of production and distribution is minimized, while respecting the product lifetime and the delivery capacity constraints. This study attempts to develop intuition into zero‐inventory production‐distribution systems under pool‐point delivery by considering several variants of the above setting. These include multiple trucks, a modifiable production rate, and alternative objectives. Using a combination of theoretical analysis and computational experiments, we gain insights into optimizing the total cost of a production‐delivery plan by understanding the trade‐off between production and transportation.     

Unobserved heterogeneity and the analysis of longitudinal spatial choice data

This paper tackles the problem of handling uncontrolled heterogeneity due to unobserved influences on the decision process of spatial choice. It concentrates upon a discrete-time/‘random-effects’ approach to the problem of unobserved heterogeneity and documents parametric and non-parametric methods of specifying and estimating models which can cope with unobserved heterogeneity.     

Disability and identity: the challenge of epilepsy

Through examining the case of people with epilepsy (which, as we demonstrate, has an ambiguous status in relation to both popular and academic conceptions of disability) we explore the fluid, negotiable and contingent nature of identity and, in particular, the identification as ‘disabled’. Disability, we argue, cannot be reduced to either biology or social oppression, or even primarily to biological or social factors: it is the outcome of a complex interaction between a multiplicity of factors – biological, environmental, social, psychological, cultural and political – which will interact and be experienced differently by different people, at different times and in different situations. Rather than conceiving of disability in ‘all or nothing’ terms and of differing explanations as competing and mutually exclusive, it would be more productive to see them as partial and potentially complementary contributions to the better understanding of a complex and multifarious reality.     

The Cost of High Unemployment

In response to R. A. B. Leaper's challenge in the last issue of this journal we present a report which we have just prepared for the BBC North-East. We believe that a better understanding of the costs of high unemployment to the country is needed to inform decisions on how much we can afford to pay to tackle the problem. In the final section of the paper we show how this evidence can be of value in costing policy options.
The last detailed costings of unemployment were published in 1982 for the financial year 1981/82. In February 1982 it appears that a political decision was taken not to publish the latest Treasury estimate updating their 1981 calculations. Since then numerous parliamentary questions on the subject have received very limited answers disputing the validity of the whole exercise.     

Polymorphic fundatrices in thimbleberry aphid — ecology and maintenance

The thimbleberry aphid,Masonaphis maxima (Mason) lives on patches of plants that support 3,4 or 5 generations depending on site and weather. The life cycle requires sexual females and males to produce overwintering eggs. The eggs hatch in the spring to produce the first ’fundatrix’ generation; subsequent generations are produced parthenogenically. Males and other morphs are produced by wingless virginoparae, but sexual females are produced by ’gynoparae’, a winged morph that is specialized to produce only sexual females. The fundatrices have no indication of the number of generations that the plants will support in the current year. There are two fundatrix types that coexist in different ratios depending on the number of generations supported by the patch the previous year. One type produces sexual females in generations 3 and 5, and males in generations 4 and 5; the other type produces sexual females in generations 4 and 5, and males in generations 3, 4 and 5. The dimorphism adapts the aphid to its heterogeneous and somewhat unpredictable environment. The role of sex in the maintenance of the dimorphism is discussed. This is the first report of fundatrix polymorphism and consequent differential sex expression in aphids.     

A general method of constructing E(s2)-optimal supersaturated designs

There has been much recent interest in supersaturated designs and their application in factor screening experiments. Supersaturated designs have mainly been constructed by using the E ( s ²)-optimality criterion originally proposed by Booth and Cox in 1962. However, until now E ( s ²)-optimal designs have only been established with certainty for n experimental runs when the number of factors m is a multiple of n-1 , and in adjacent cases where m = q ( n -1) + r (| r | 2, q an integer). A method of constructing E ( s ²)-optimal designs is presented which allows a reasonably complete solution to be found for various numbers of runs n including n ,=8 12, 16, 20, 24, 32, 40, 48, 64.     

Non-Gaussian Ornstein–Uhlenbeck-based models and some of their uses in financial economics

Non-Gaussian processes of Ornstein–Uhlenbeck (OU) type offer the possibility of capturing important distributional deviations from Gaussianity and for flexible modelling of dependence structures. This paper develops this potential, drawing on and extending powerful results from probability theory for applications in statistical analysis. Their power is illustrated by a sustained application of OU processes within the context of finance and econometrics. We construct continuous time stochastic volatility models for financial assets where the volatility processes are superpositions of positive OU processes, and we study these models in relation to financial data and theory.