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Parent Generation (parent + generation)

Distribution by Scientific Domains

Medical Sciences	40%
Business, Economics, Finance and Accounting	40%

Selected Abstracts

Developmental toxicity of UV filters and environmental exposure: a review

INTERNATIONAL JOURNAL OF ANDROLOGY, Issue 2 2008
Margret Schlumpf
Summary Several ultraviolet (UV) filters exhibit estrogenic, some also anti-androgenic activity. They are present in waste water treatment plants, surface waters and biosphere including human milk, suggesting potential exposure during development. Developmental toxicity was studied in rats for the UV filters 4-methylbenzylidene camphor (4-MBC, 0.7, 7, 24, 47 mg/kg/day) and 3-benzylidene camphor (3-BC, 0.07, 0.24, 0.7, 2.4, 7 mg/kg/day) administered in chow to the parent generation before mating, during pregnancy and lactation, and to the offspring until adulthood. Neonates exhibited enhanced prostate growth after 4-MBC and altered uterine gene expression after both chemicals. 4-MBC and 3-BC delayed male puberty and affected reproductive organ weights of adult offspring. Effects on the thyroid axis were also noted. Expression and oestrogen sensitivity of oestrogen-regulated genes and nuclear receptor coregulator levels were altered at mRNA and protein levels in adult uterus, prostate and brain regions involved in gonadal control and sexual behaviour. Female sexual behaviour was impaired by both filters; 3-benzylidene camphor caused irregular cycles. Classical endpoints exhibited lowest observed adverse effect levels (LOAELs) and no observed adverse effect levels (NOAELs) of 7/0.7 mg/kg for 4-MBC and 0.24/0.07 mg/kg for 3-BC. Molecular endpoints were affected by the lowest doses studied. Our data indicate that the potential risk posed by endocrine active UV filters warrants further investigations. [source]

Social facilitation affects longevity and lifetime reproductive success in a self-fertilizing land snail

OIKOS, Issue 3 2000
Bruno Baur
Factors that reduce the reproductive output of self-fertilizing hermaphrodites are receiving increasing attention. The combined effects of reduced fecundity of selfing parents and inbreeding depression of the progeny have been referred to as self-fertilization depression. In isolated freshwater snails the reproductive output of selfing individuals also decreases due to the lack of social facilitation (absence of a conspecific). We examined the effect of social facilitation on lifetime reproductive success (number of young produced and longevity) over two generations in the simultaneously hermaphroditic land snail Balea perversa. In a parallel study we showed that B. perversa kept singly and in pairs reproduced exclusively by self-fertilization. In the parent generation, snails kept singly produced less offspring than snails kept in pairs. The difference in lifetime number of young was mainly due to differences in adult life span. Snails of the two groups did not differ in reproductive rate (number of young produced per 100 d of reproductive life) and hatchling size. In the offspring generation, snails kept singly did not differ from individuals kept in pairs in the lifetime number of young and hatchling survival. As in the parent generation, snails kept singly reproduced during a shorter period than snails kept in pairs. However, the shorter reproductive life span of snails kept singly was compensated for by a slightly (but not significantly) higher reproductive rate which resulted in a similar number of offspring produced for both groups. In both generations, snails of the two groups did not differ in size at first reproduction, adult growth rate and size at death. These findings suggest that social facilitation may affect longevity in selfing B. perversa. [source]

Pensions and fertility incentives

CANADIAN JOURNAL OF ECONOMICS, Issue 1 2005
Robert Fenge
In the model of a small open economy, higher fertility is associated with a reduction of lifetime labour supply. The optimum share of fertility-related pensions is always below unity, but generally positive. The former is true, since individuals do not take into account the impact of their labour supply choice on the parent generation. It is demonstrated that child allowances are equivalent to fertility-related pensions as instruments to achieve the optimum allocation. JEL classification: H23, H55, J13 Pensions et mesures d'incitation à la fertilité., Cet article propose d'évaluer, dans le cadre d'une réforme d'un système de retraite par répartition, l'impact sur le bien-être social de l'introduction d'une prestation pour enfant lorsque la fertilité est endogène. Dans le modèle de petite économie ouverte, une fertilité plus forte réduit l'offre de travail durant le cycle de vie. La quote-part optimale des pensions réliées à la fertilité est toujours inférieure à l'unité, mais généralement positive. La première remarque est vraie puisque les individus ne tiennent pas compte de l'impact de leur offre de travail sur la génération des parents. Il est démontré que des allocations familiales sont équivalentes aux pensions reliées à la fertilité comme moyen d'atteindre l'allocation optimale. [source]

A genetic algorithm and the Monte Carlo method for stochastic job-shop scheduling

INTERNATIONAL TRANSACTIONS IN OPERATIONAL RESEARCH, Issue 6 2003
Y. Yoshitomi
Abstract This paper proposes a method for solving stochastic job-shop scheduling problems using a hybrid of a genetic algorithm in uncertain environments and the Monte Carlo method. First, the genetic algorithm in uncertain environments is applied to stochastic job-shop scheduling problems where the processing times are treated as stochastic variables. The Roulette strategy is adopted for selecting the optimum solution having the minimum expected value for makespan. Applying crossover based on Giffler and Thompson's algorithm results in two offspring inheriting the ancestor's characteristics as the operation completion times averaged up to the parent's generation. Individuals having very high frequency through all generations are selected as the good solutions. Second, the Monte Carlo method is effectively used for finding out the approximately optimum solution among these good solutions. [source]

Ecological Differences in Weight, Length, and Weight for Length of Mexican American Children in the WIC Program

JOURNAL FOR SPECIALISTS IN PEDIATRIC NURSING, Issue 3 2008
Elizabeth Reifsnider PhD, WHNP
PURPOSE.,Examine factors common in the environments of children who obtain services from a WIC program to determine if differences in ecological/environmental factors can be found in the children who differ in weight, length, and weight for length. DESIGN AND METHODS.,Cross-sectional study of 300 children, 100 each who were stunted, normal weight for length, or overweight. Instruments used were NCATS, ARSMA II, 24-hr diet recall, and Baecke Activity Questionnaire. RESULTS.,Significant differences were present in children's diet, parents' BMI, parents' generation in United States, parents' activity levels, and maternal,child relationship. PRACTICE IMPLICATIONS.,Encourage parents to adopt family approaches to encourage normal body size in children. [source]