Urban bird community composition influenced by size of urban green spaces,presence of native forest,and urbanization

Urban Ecosystems - Understanding what determines wildlife species richness and community composition in urban green spaces is important for wildlife management and urban planning. Numerous studies...     

Simplified estimation of the parameters of exponential distribution from samples censored in the middle

This paper presents the small sample optimum choice of k ≤n + r₁ ? r₂ + 1) order statistics for the best linear unbiased estimates (BLUES) of the parameters μ and σ or σ alone ( μ known) when the sample is Type II censored in the middle retaining only r₁ lower and n - r₂ + 1 upper order statistics. For n = 3(1)10, k = 2(1)4, r₁ = O(1) (n?2) and r₂ = (r₁ +2) (l)n, the optimum ranks, the coefficients of the BLUEs have been presented in Table I     

FATHERS TAKING PARENTAL LEAVE AND THEIR INVOLVEMENT WITH CHILDREN

Parental leave has been promoted as a way to enhance employed fathers’ involvement with their children. Leave patterns, factors affecting these patterns and the impact of taking leave on involvement with children were assessed for fathers in 38 couples. Parents, contacted through their employers, completed self-administered questionnaires on their work schedule changes after the arrival of a baby, reactions to these changes, childcare activities and attitudes. The mother's and father's assessments in each couple were averaged to measure 21 different aspects of fathers’ involvement. Fathers who took leave were more likely to share some specific childcare tasks with mothers than fathers who did not take leave but no differences were found for time spent with children or taking responsibility for childcare. Parents’ equalitarian beliefs, income and education had more impact than taking leave on fathers’ overall involvement in childcare.

Se ha promovido La Licencia de Paternidad como una forma para ayudar a los padres que están empleados a involucrarse con sus hijos. Los patrones de estas licencias, los factores que afectan estos patrones, y el impacto que tiene esta licencia en las relaciones con los niños fueron evaluadas por los padres en 38 parejas. Los padres, contactados por sus empleadores, completaron cuestionarios sobre los cambios en sus horarios de trabajo después de la llegada del bebé, las reacciones a esos cambios, actividades para el cuidado del niño, y sus actitudes. Se hizo un promedio midiendo los 21 diferentes aspectos del involucro de los padres presentado en las evaluaciones hechas por la madre y el padre en cada pareja. Los padres que tomaron licencia de paternidad, generalmente compartieron con la madre algunos aspectos específicos para el cuidado del niño a diferencia de los padres que no tomaron la licencia, pero no se encontraron diferencias sobre el tiempo empleado con los niños o en las responsabilidades del cuidado de los mismos. En general, las creencias sobre la igualdad, la situación económica y la educación de los padres, tuvo más impacto que el involucrarse totalmente en el cuidado de los niños de los padres con licencia de paternidad.     

Measuring Cohabitation and Family Structure in the United States: Assessing the Impact of New Data From the Current Population Survey

In 2007, the Current Population Survey (CPS) introduced a measure that identifies all cohabiting partners in a household, regardless of whether they describe themselves as ??unmarried partners?? in the relationship to householder question. The CPS now also links children to their biological, step-, and adoptive parents. Using these new variables, we analyze the prevalence of cohabitation as well as the demographic and socioeconomic characteristics of different-sex cohabiting couples during the years 2007?C2009. Estimates of cohabitation produced using only unmarried partnerships miss 18?% of all cohabiting unions and 12?% of children residing with cohabiting parents. Although differences between unmarried partners and most newly identified cohabitors are small, newly identified cohabitors are older, on average, and are less likely to be raising shared biological or adopted children. These new measures also allow us to identify a small number of young, disadvantaged couples who primarily reside in households of other family members, most commonly with parents. We conclude with an examination of the complex living arrangements and poverty status of American children, demonstrating the broader value of these new measures for research on American family and household structure.     

Human Variability in Susceptibility to Toxic Chemicals— A Preliminary Analysis of Pharmacokinetic Data from Normal Volunteers

The tenfold "uncertainty" factor traditionally used to guard against human interindividual differences in susceptibility to toxicity is not based on human observations. To begin to build a basis for quantifying an important component of overall variability in susceptibility to toxicity, a data base has been constructed of individual measurements of key pharmacokinetic parameters for specific substances (mostly drugs) in groups of at least five healthy adults. 72 of the 101 data sets studied were positively skewed, indicating that the distributions are generally closer to expectations for log-normal distributions than for normal distributions. Measurements of interindividual variability in elimination half-lives, maximal blood concentrations, and AUC (area under the curve of blood concentration by time) have median values of log10 geometric standard deviations in the range of 0.11-0.145. For the median chemical, therefore, a tenfold difference in these pharmacokinetic parameters would correspond to 7-9 standard deviations in populations of normal healthy adults. For one relatively lipophilic chemical, however, interindividual variability in maximal blood concentration and AUC was 0.4--implying that a tenfold difference would correspond to only about 2.5 standard deviations for those parameters in the human population. The parameters studied to date are only components of overall susceptibility to toxic agents, and do not include contributions from variability in exposure- and response-determining parameters. The current study also implicitly excludes most human interindividual variability from age and illness. When these other sources of variability are included in an overall analysis of variability in susceptibility, it is likely that a tenfold difference will correspond to fewer standard deviations in the overall population, and correspondingly greater numbers of people at risk of toxicity.