An evaluation of the performance of kernel estimators for graduating mortality data

In the graduation of the age-specific mortality pattern, recent emphasis has been placed on the use of kernel regression estimators. Three such estimators are the Nadaraya-Watson, Gasser-Muller and kernel weighted local linear estimators. This paper discusses the theoretical background of each estimator and evaluates their accuracy in graduating age-specific mortality using data for France, Japan and Sweden. For comparison, we also fit the Heligman-Pollard model and its nine-parameter variant by Kostaki. The Gasser-Muller estimator is found to be superior to the two other kernel estimators in that it is both more stable and not influenced by boundary effects. Furthermore, compared with the two parametrric models, the Gasser-Muller estimator provides a more satisfactory graduation, especially at older adult ages, in terms both of smoothness and of fidelity between the observed and graduated rates.     

The effects of high- and moderate-resistance training on muscle function in the elderly

The purpose of this study was to investigate the effects of a 12-week resistance-training program on muscle strength and mass in older adults. Thirty-three inactive participants (60-74 years old) were assigned to 1 of 3 groups: high-resistance training (HT), moderate-resistance training (MT), and control. After the training period, both HT and MT significantly increased 1-RM body strength, the peak torque of knee extensors and flexors, and the midthigh cross-sectional area of the total muscle. In addition, both HT and MT significantly decreased the abdominal circumference. HT was more effective in increasing 1-RM strength, muscle mass, and peak knee-flexor torque than was MT. These data suggest that muscle strength and mass can be improved in the elderly with both high- and moderate-intensity resistance training, but high-resistance training can lead to greater strength gains and hypertrophy than can moderate-resistance training.     

The causal relationship between female labor supply and fertility in the USA: updated evidence via a time series multi-horizon approach

The purpose of this paper is to investigate the causality between female labor supply and fertility in the presence of auxiliary variables such as education, female wages, and male relative cohort size. We employ annual time series data spanning the period 1948 to 2007 for both an aggregate and an age-specific group. Our econometric specification follows closely the concepts and procedures proposed by Dufour and Renault (Econometrica 66(5):1099–1125, 1998) and Dufour et al. (J Econom 132:337–362, 2006) in that we conduct multi-horizon causality tests that allow for direct and indirect effects to take place. The sign and economic importance of our results is assessed via the estimation of impulse response functions. Our results establish bidirectional indirect causality between female labor supply and fertility and suggest interesting causal chains among the system variables. Causality effects are stronger for the age-specific group.