Old Individuals (old + individual)

Distribution by Scientific Domains

Selected Abstracts


This study investigates whether models of forward-looking behavior explain the observed patterns of heavy drinking and smoking of men in late middle age in the Health and Retirement Study better than myopic models. We develop and estimate a sequence of nested models that differ by their degree of forward-looking behavior. Our empirical findings suggest that forward looking models fit the data better than myopic models. These models also dominate other behavioral models based on out-of-sample predictions using data of men aged 70 and over. Myopic models predict rates of smoking for old individuals, which are significantly larger than those found in the data on elderly men. [source]

Relationship between cribra orbitalia and enamel hypoplasia in the early medieval Slavic population at Borovce, Slovakia

Z. Obertová
Abstract Cribra orbitalia and enamel hypoplasia were examined in an early medieval (8th to beginning of 12th century AD) skeletal sample of 451 individuals from Borovce, Slovakia. More than 40% of these individuals died before reaching 20 years of age. The relationship between the occurrence of orbital and enamel lesions was analysed by focusing on the age-specific distribution, and on its influence on demographic parameters. Both features were found in 11.2% of the observed skulls. The presence of orbital and dental lesions showed a considerable impact on mortality as well as the life expectancy. Generally, the highest mortality was observed among 0,4 year old individuals. The greatest discrepancy in the demographic parameters, however, appeared between the affected and unaffected individuals aged 10,14 and 15,19 years. In these two age groups the co-occurrence of both lesions was most frequently recorded. These individuals obviously had a history of sickness, and thus could not cope with further bouts of disease and with the increased physiological demands of pubertal growth. The missing correlation in younger age categories can be largely explained by the difficulty of macroscopically examining the permanent dentition, since an interrelationship between the age at hypoplasia development and the occurrence of cribra orbitalia was detected. Several differences between the individuals with enamel defects and both conditions were observed in the distribution of age at hypoplasia formation. According to these results, several factors, such as impaired health status, growth demands and diet, influence the development of enamel hypoplasia and cribra orbitalia in a particular population. It is possible that after reaching a certain threshold, the underlying factors act synergistically in a kind of vicious cycle as the balance between the immune system, metabolism, and exogenous factors such as pathogens and nutrition, is disturbed. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Age changes in bone microstructure: do they occur uniformly?

G. A. Macho
Abstract Age estimations based on conventional multifactorial methods were compared with trends observed in the internal morphology of bones obtained from high-resolution µCT. Specifically, average trabecular thickness and number of trabeculae/mm transect were determined in the non-load-bearing capitate (hand) and the load-bearing navicular (foot). The µCT findings reveal age-related trends but,surprisingly,these correspond only loosely with the ages assigned by conventional ageing methods, and are also not in accordance with what would be predicted from biomechanical considerations: trabeculae tend to be thinner in the (habitually) load-bearing navicular than in the (habitually) non-load-bearing capitate. While the statistically significant correlation between trabecular thickness and number of trabeculae would suggest a compensatory mechanism between these two aspects of microanatomy, they are not correlated with the assigned ages and, importantly, may differ between sexes. Only in females is there an unequivocal trend towards trabecular thickness increase with age. These findings, although unexpected, can be reconciled with recent histological evidence and assumed average activity levels in historical populations. Conversely, changes in trabecular number are less clear-cut and may be due to the lack of very old individuals in the sample. Nevertheless, the trends observed for trabecular thickness, as well as for trabecular number, seem to imply that the higher incidence of osteoporosis in women could be explained from a structural point of view alone. Copyright © 2005 John Wiley & Sons, Ltd. [source]

Intergenerational Transfers, and Public Pensions in a Non Altuistic Setting: a Public Choice Model

LABOUR, Issue 1 2001
Furio Camillo Rosati
The paper presents a model based on non-altruistic individuals, where middle aged and old individuals influence the decisions about public social security system. This is an alternative or a complement to private intergenerational transfers. Fertility is endogenous, as children are seen as an assets in the process of transferring resources to old age by the network of intergenerational intrafamily transfers. Expectations about the Government social security budget balance play a crucial role. We also present some empirical estimates of the fertility and pension ,demand' function for some developed countries. It emerges that both can be treated as endogenous, and the results are coherent with the theory. [source]

Uncoupling nitrogen requirements for spring growth from root uptake in a young evergreen shrub (Rhododendron ferrugineum)

T. Lamaze
Abstract , , Internal cycling of nitrogen (N) was investigated in a subalpine field population of the evergreen shrub Rhododendron ferrugineum during spring growth. , , The foliar nitrogen of 5-yr-old-plants was directly labeled with 15N and subsequently traced to all plant compartments. In addition, 15N-ammonium uptake was estimated in glasshouse experiments. , , Before shoot growth, redistribution of 15N occurred in the plant without net N transfer. During spring development, the decreases in both leaf 15N and total N were almost identical in terms of percentage, and most of the 15N withdrawn from the leaf compartments was recovered in the growing shoots. Net changes in the N contents of the various leaf and woody compartments indicate that internal remobilization (especially from 1-yr-old leaves) could have met most of the N needs of new shoot growth. Simultaneously, the rate of mineral N uptake was very low. , , Thus, leaves in young plants provide N for new shoots (by contrast with old individuals) and allow, with woody tissues, almost complete uncoupling of N requirement for spring growth from root uptake. [source]