Combined Effects of Contaminant Desorption and Toxicity on Risk from PAH Contaminated Sediments

A strong inverse correlation was observed between the polycyclic aromatic hydrocarbon (PAH) mass fraction desorbed, a surrogate measure of bioavailability, and relative carcinogenicity, as quantified by potency equivalency factors (PEFs), for two study sediments from the New York/New Jersey Harbor estuary. Because compounds with the highest toxicity, such as dibenz(a,h)anthracene and benzo(a)pyrene (BAP), also tended to be the least rapidly and least extensively desorbed, the U.S. Environmental Protection Agency (EPA) default guidance may dramatically overestimate risk from exposure to PAH-contaminated soils or sediments. A "relative risk index" (RRI) was developed to account for the combined effects of compound-specific bioavailability and toxic potency in estimating excess cancer risk. Using this approach, estimated excess cancer risk may be diminished by as much as a factor of 159 times versus default EPA guidance. Also, the hierarchy of estimated risk between study sediments and among treatment fractions of study sediments differed using the two approaches, implying that the default approach may inaccurately determine site clean-up priorities. The percentage contribution of each potentially carcinogenic priority PAH to total excess cancer risk was computed under various scenarios. In each case, the contribution of BAP to total excess cancer risk was remarkably invariable, for example, ranging from 48% to 52% in one sediment, and 44% to 54% in the other, over four different exposure durations. These results suggest that BAP may be an excellent indexing compound for gauging relative exposure risk across sediments. Other important contributors to total excess cancer risk were benz(a)anthracene and dibenz(a,h)anthracene. Together, these three compounds comprised nearly 90% of total excess cancer risk from all PAHs in every scenario. This integrated RRI approach may enable regulators to more accurately gauge relative risks and make more informed sediment management decisions.     

Objective and subjective social indicators of the quality of life in American SMSA'S: A reanalysis

The paper examines and critiques Schneider's work that related the subjective and objective indicators of quality of life in American cities. The work then employs data collected by Liu in 1973, and the Institute for Survey Research in 1972 as part of their national election study for 41 large and medium-sized Standard Metropolitan Statistical Areas (SMSA's) to re-examine the question of the relationship between the objective and subjective factors. Although the results of this paper are in general comparable with those obtained by Schneider, there are individual cases where they differ. The paper then concludes with a discussion of the reasons why objective and subjective indicators may coincide.     

A solution to a conjecture on the generalized connectivity of graphs

The generalized k-connectivity \(\kappa _k(G)\) of a graph G was introduced by Chartrand et al. in (Bull Bombay Math Colloq 2:1–6, 1984), which is a nice generalization of the classical connectivity. Recently, as a natural counterpart, Li et al. proposed the concept of generalized edge-connectivity for a graph. In this paper, we consider the computational complexity of the generalized connectivity and generalized edge-connectivity of a graph. We give a confirmative solution to a conjecture raised by S. Li in Ph.D. Thesis (2012). We also give a polynomial-time algorithm to a problem of generalized k-edge-connectivity.     

Childcare policies and services in Hong Kong after the handover: Beyond a feminist critique

This article reviews the development of childcare policies and services in Hong Kong after the handover, gauging it with two standards: promoting the equal development of children and gender equality in our society. Statistics derived from data taken from multiple sources show that the government has been sticking to a “positive non‐intervention approach” to welfare development and that the male breadwinner/female carer model prevalent in this region was shaped and strengthened by current childcare policies and services. The current provision of childcare services is insufficient to guarantee the equal use of childcare among children of different socioeconomic backgrounds, or to ease the tension between the needs of childcare and job requirements in a family, or to emancipate married women from the domestic sphere. A “generative welfare approach” that collects fiscal resources and redistributes them strategically with a systemic mind‐set has been suggested for social policy and service planning, including spending the money in the right place, launching smart and practical policies that can achieve both pragmatic effects and ideological improvement in the area of gender equality, providing financial support or subsidies to a company for the provision of parental leave, and increasing the provision of quality childcare services.     

Complexity analysis for maximum flow problems with arc reversals

We provide a comprehensive study on network flow problems with arc reversal capabilities. The problem is to identify the arcs to be reversed in order to achieve a maximum flow from source(s) to sink(s). The problem finds its applications in emergency transportation management, where the lanes of a road network could be reversed to enable flow in the opposite direction. We study several network flow problems with the arc reversal capability and discuss their complexity. More specifically, we discuss the polynomial time algorithms for the maximum dynamic flow problem with arc reversal capability having a single source and a single sink, and for the maximum (static) flow problem. The presented algorithms are based on graph transformations and reductions to polynomially solvable flow problems. In addition, we show that the quickest transshipment problem with arc reversal capability and the problem of minimizing the total cost resulting from arc switching costs are NP\mathcal{NP} -hard.     

Recurrence relations and Benford’s law

Statistical Methods & Applications - There are now many theoretical explanations for why Benford’s law of digit bias surfaces in so many diverse fields and data sets. After briefly...     

Social Self‐Control,Externalizing Behavior,and Peer Liking Among Children with ADHD‐CT: A Mediation Model

This study investigated the role of externalizing behavior as a mediator of the relation between social self‐control and peer liking among children with attention‐deficit/hyperactivity disorder‐combined type (ADHD‐CT). A model was proposed whereby externalizing behavior would fully statistically account for the direct relation of social self‐control to peer liking. One hundred seventy‐two children ages 7.0–9.9 years with ADHD‐CT were rated by their teachers regarding their social self‐control and by their parents and teachers regarding their rates of externalizing behavior. Same‐sex classmates provided ratings of overall liking. Structural equation modeling was used to assess the proposed model. Results supported the proposed model of externalizing behavior as fully statistically accounting for the relation of social self‐control to peer liking. This study demonstrated the crucial role that externalizing behaviors play in the social impairment commonly seen among children with ADHD‐CT.     

Parental Involvement Promotes Rural African American Youths’ Self‐Pride and Sexual Self‐Concepts

This study, an evaluation of the Strong African American Families Program, was designed to determine whether intervention‐induced changes in targeted parenting behaviors were associated with young adolescents’ development of racial pride, self‐esteem, and sexual identity. Participants were 332 African American mothers and their 11‐year‐old children in 9 rural Georgia counties. Families were randomly assigned to a control group or an intervention group. Unlike those in the control families, mothers in the intervention group reported increases in targeted parenting behaviors, which promoted self‐esteem, positive racial identity, and positive sexual self‐concepts among their children. These findings expand the study of African American youths’ identity development by including broader domains of identity and parenting processes other than racial socialization.     

Research Review: Parents' service experience – a missing element in research on foster care case outcomes

A large body of child protection literature focuses on termination of parental rights, family reunification, and children's re‐entry into care as outcomes for children in foster care. Studies have investigated child, placement, family, and parent variables as predictors of case outcome. However, one important group of variables remains largely unstudied: factors related to parents’ service experience. Parents’ service experience includes parents’ perceptions of and involvement in the various services in which they must participate in order to recover their children from foster care (e.g. mandated treatment programmes such as substance abuse rehabilitation, parenting skills classes, etc.). The parental perspective on the foster care process is a critical element in the life of a child protection case, and its influence on case outcome must be explored. A brief review of the current literature on case outcome predictors is provided and parents’ service experience is highlighted as an area in need of investigation. Suggestions for the measurement of parents’ service experience are also offered.