On The Method of Discrete Probability Distributions in Risk and Reliability Calculations–Application to Seismic Risk Assessment

If the point of view is adopted that in calculations of real-world phenomena we almost invariably have significant uncertainty in the numerical values of our parameters, then, in these calculations, numerical quantities should be replaced by probability distributions and mathematical operations between these quantities should be replaced by analogous operations between probability distributions. Also, practical calculations one way or another always require discretization or truncation. Combining these two thoughts leads to a numerical approach to probabilistic calculations having great simplicity, power, and elegance. The philosophy and technique of this approach is described, some pitfalls are pointed out, and an application to seismic risk assessment is outlined.     

The Achievement Factor in Igbo Receptivity to Industrialization

On a expliqué les différences de développement économique entre les trois principaux groupes culturels nigériens - Hausa, Yoruba, Igbo - par l'existence dans leurs sociétés traditionnelles d'évaluations différentes de l'ambition et de l'effort personnels. Adoptant une autre perspective que l'approche psychologique de McClelland sur le niveau de réalisation, l'auteur indique que l'oeuvre d'une collectivité serait en rapport plus étroit avec le caractére de son édifice social qu'il ne Test avec la structure de la personnalité de ses membres.     

Effect of urbanization on surface water chemistry in south-central Texas

The use of state factors can adequately describe the biogeochemistry and geochemistry of relatively undisturbed surface waters. Watersheds with increasing proportions of urban and suburban land use, particularly in sub-tropical, semi-arid and arid urban areas, that utilize irrigation for turfgrass and landscaping may have a low flow urban signature that relates to the source water used by municipal water suppliers. We examined thirteen watersheds; four with waste water treatment plants (24–67% urbanization), four rural (< 30% urbanization) and five urban (> 30% urbanization) in a humid sub-tropical oak savannah in south-central Texas. Three of our urban and one of our rural watersheds displayed the signature of municipal tap water. Three out of four watersheds with waste water treatment plants displayed the signature of treated sewage effluent. We suggest as a result of this study that the chemistry of municipal tap water particularly that with high sodium and bicarbonate, used in urban watersheds for irrigating turfgrass and landscapes may have detrimental effects on base flow stream water quality after it has interacted with watershed soils.     

Local Control Strategy: Simple Analyses of Air Pollution Data Can Reveal Heterogeneity in Longevity Outcomes

Claims from observational studies that use traditional model specification searches often fail to replicate, partially because the available data tend to be biased. There is an urgent need for an alternative statistical analysis strategy, that is not only simple and easily understood but also is more likely to give reliable insights when the available data have not been designed and balanced. The alternative strategy known as local control first generates local, nonparametric effect‐size estimates (fair treatment comparisons) and only then asks whether the observed variation in these local estimates can be predicted from potential confounding factors. Here, we illustrate application of local control to a historical air pollution data set describing a “natural experiment” initiated by the federal Clean Air Act Amendments of 1970. Our reanalysis reveals subgroup heterogeneity in the effects of air quality regulation on elderly longevity (one size does not fit all), and we show that this heterogeneity is largely explained by socioeconomic and environmental confounders other than air quality.     

The Role of Social Support in Bereavement

Spousal bereavement involves a social network crisis. The individual's response is influenced by prebereavement personality factors and preexisting social network characteristics. The impact of the loss on the individual and other network members, and the presence or absence of concurrent stressors, will determine the "goodness of fit" between the support offered and the needs of the bereaved and perception of the environment as helpful or unhelpful. An inadequate social network is associated with high distress over the course of bereavement. Intervention aimed at increasing social support can decrease the distress of bereavement.     

GENDER-COHORT SUCCESSION AND RETIREMENT AMONG OLDER MEN AND WOMEN, 1951 TO 1984

Long-term trends in occupational change and retirement policy have influenced the relative labor force participation and retirement patterns of subgroups of the older population. Structural changes in the economy have had a large impact on older men and women, pushing the former out of the labor force while pulling the latter in. Meanwhile, the expansion of pension programs for the aged has generally increased the early retirement of men under age 65. Time-series analyses of these trends between 1951 and 1984 point to the specific influences of these factors on gender-cohorts.     

Family cap provisions and changes in births and abortions

As part of welfare reform efforts in the 1990s, 23 states implemented family caps, provisions that deny or reduce cash assistance to welfare recipients who have additional births. We use birth and abortion records from 24 states to estimate effects of family caps on birth and abortion rates. We use age, marital status, and completed schooling to identify women at high risk for use of public assistance, and parity (number of previous live births) to identify those most directly affected by the family cap. In family cap states, birth rates fell more and abortion rates rose more among high-risk women with at least one previous live birth compared to similar childless women, consistent with an effect of the family cap. However, this parity-specific pattern of births and abortions also occurred in states that implemented welfare reform with no family cap. Thus, the effects of welfare reform may have differed between mothers and childless women, but there is little evidence of an independent effect of the family cap.