Development and evaluation of the physical activity questionnaire for elderly Japanese: the Nakanojo study

The Physical Activity Questionnaire for Elderly Japanese (PAQ-EJ) is a self-administered physical activity questionnaire for elderly Japanese; the authors report here on its repeatability and direct and indirect validity. Reliability was assessed by repeat administration after 1 month. Direct validation was based on accelerometer data collected every 4 s for 1 month in 147 individuals age 65-85 years. Indirect validation against a 10-item Barthel index (activities of daily living [ADL]) was completed in 3,084 individuals age 65-99 years. The test-retest coefficient was high (r = .64-.71). Total and subtotal scores for lower (transportation, housework, and labor) and higher intensity activities (exercise/sports) were significantly correlated with step counts and durations of physical activity <3 and >or=3 METs (r = .41, .28, .53), respectively. Controlling for age and ADL, scores for transportation, exercise/sports, and labor were greater in men, but women performed more housework. Sex- and ADL- or age-adjusted PAQ-EJ scores were significantly lower in older and dependent people. PAQ-EJ repeatability and validity seem comparable to those of instruments used in Western epidemiological studies.     

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.     

An application of catastrophe theory to management science process

Practicing management scientists often complain of the alleged irrational behavior on the part of the managers they are trying to serve, particularly when a manager suddenly and unexpectedly shifts behavior from one of support to one of resistance. The authors feel such behavior is only believed to be irrational because the management scientist is using the wrong mental model when projecting past behavioral patterns into the future. This paper attempts to solve this problem by using the newly developed catastrophe theory to develop a different model where sudden shifts in behavior are considered perfectly rational and explainable. The basic implication that is drawn from this new model is that successful implementation of management science depends on a sequence of interactions with the ultimate model user and that care in the structuring of these interactions can greatly enhance the probability of eventual user acceptance.     

Econometric analysis and managerial decision making

Econometric analysis is concerned with the quantitative relationships between economic variables and it can provide an important input into the decision making process of managers. Typically econometrics differs from other apsects of management science in that it considers problems primarily, though not exclusively, from a background of economics rather than of other disciplines and behaviour is usually dealt with at higher levels of data aggregation than the individual firm.This paper considers some applications of typical econometrics to the general area of managerial decision making, where primarily the techniques have a role to play in assisting the general process of data analysis. Initially discussion is pointed towards the use of the analysis for predictive purposes and the contrast with time series methods. Subsequently examples are presented where the objective is to obtain a better understanding of individual economic relationships that aim to be important inputs into the decision making process, for example cost and revenue analysis. Finally, an example is given of how these ideas contribute more generally to the activity of model building for the firm as a whole both for the purpose of forecasting and policy simulation.     

Local volunteers respond to the Rena oil spill in Maketū, New Zealand

Following the MV Rena grounding and oil spill in the Bay of Plenty, New Zealand in October 2011, the Māori community of Maketū were quick to respond to the arrival of oil on their beaches. They asserted their rangatiratanga by establishing their marae as a base and successfully coordinated a clean-up by more than 450 volunteers, feeding these volunteers every day. We interviewed 11 clean-up leaders and volunteers in Maketū to gather information about how the oil spill affected people in the community and how they ensured the success of their clean-up efforts. Many volunteers returned to help with the clean-up day after day over several weeks. Concepts of kaitiakitanga and manaakitanga underpinned the work of the Maketū clean-up organisers. Participants attributed the success of the Maketū clean-up to the speed with which they responded, the support they received from their community and local businesses, and their local knowledge.     

Estimation of an Asymmetric Stochastic Volatility Model for Asset Returns

A stochastic volatility model may be estimated by a quasi-maximum likelihood procedure by transforming to a linear state-space form. The method is extended to handle correlation between the two disturbances in the model and applied to data on stock returns