SOME CHARACTERIZATIONS OF THE CAUCHY DISTRIBUTION

If X and Y are independent standard Cauchy random variables then (i) Y and (X+Y)/(1-Xu) are independent, (ii) X and (X + Y)/(1 -XU) are identically distributed, and (iii) X and 2X/(1-X²) are identically distributed. Each of these three properties is shown to characterize the Cauchy distribution among absolutely continuous distributions. Some related uniform characterizations are discussed.     

A Meta-Analysis of Children's Hand-to-Mouth Frequency Data for Estimating Nondietary Ingestion Exposure

Because of their mouthing behaviors, children have a higher potential for exposure to available chemicals through the nondietary ingestion route; thus, frequency of hand-to-mouth activity is an important variable for exposure assessments. Such data are limited and difficult to collect. Few published studies report such information, and the studies that have been conducted used different data collection approaches (e.g., videography versus real-time observation), data analysis and reporting methods, ages of children, locations, and even definitions of "mouthing." For this article, hand-to-mouth frequency data were gathered from 9 available studies representing 429 subjects and more than 2,000 hours of behavior observation. A meta-analysis was conducted to study differences in hand-to-mouth frequency based on study, age group, gender, and location (indoor vs. outdoor), to fit variability and uncertainty distributions that can be used in probabilistic exposure assessments, and to identify any data gaps. Results of this analysis indicate that age and location are important for hand-to-mouth frequency, but study and gender are not. As age increases, both indoor and outdoor hand-to-mouth frequencies decrease. Hand-to-mouth behavior is significantly greater indoors than outdoors. For both indoor and outdoor hand-to-mouth frequencies, interpersonal, and intra-personal variability are approximately 60% and approximately 30%, respectively. The variance difference among different studies is much bigger than its mean, indicating that different studies with different methodologies have similar central values. Weibull distributions best fit the observed data for the different variables considered and are presented in this article by study, age group, and location. Average indoor hand-to-mouth behavior ranged from 6.7 to 28.0 contacts/hour, with the lowest value corresponding to the 6 to <11 year olds and the highest value corresponding to the 3 to <6 month olds. Average outdoor hand-to-mouth frequency ranged from 2.9 to 14.5 contacts/hour, with the lowest value corresponding to the 6 to <11 year olds and the highest value corresponding to the 6 to <12 month olds. The analysis highlights the need for additional hand-to-mouth data for the <3 months, 3 to <6 months, and 3 to <6 year age groups using standardized collection and analysis because of lack of data or high uncertainty in available data. This is the first publication to report Weibull distributions as the best fitting distribution for hand-to-mouth frequency; using the best fitting exposure factor distribution will help improve estimates of exposure. The analyses also represent a first comprehensive effort to fit hand-to-mouth frequency variability and uncertainty distributions by indoor/outdoor location and by age groups, using the new standard set of age groups recommended by the U.S. Environmental Protection Agency for assessing childhood exposures. Thus, the data presented in this article can be used to update the U.S. EPA's Child-Specific Exposure Factors Handbook and to improve estimates of nondietary ingestion in probabilistic exposure modeling.     

Formerly Incarcerated Parents and Their Children

The negative effects of incarceration on child well-being are often linked to the economic insecurity of formerly incarcerated parents. Researchers caution, however, that the effects of parental incarceration may be small in the presence of multiple-partner fertility and other family complexity. Despite these claims, few studies have directly observed either economic insecurity or the full extent of family complexity. We study parent-child relationships with a unique data set that includes detailed information about economic insecurity and family complexity among parents just released from prison. We find that stable private housing, more than income, is associated with close and regular contact between parents and children. Formerly incarcerated parents see their children less regularly in contexts of multiple-partner fertility and in the absence of supportive family relationships. Significant housing and family effects are estimated even after we control for drug use and crime, which are themselves negatively related to parental contact. The findings point to the constraints of material insecurity and the complexity of family relationships on the contact between formerly incarcerated parents and their children.     

Linkages between internal and international migration: the Ilocos Norte experience

This paper reviews the arguments concerning whether internal and international migration can or should be incorporated in the same migration theories or models and examines the ways in which the 2 processes are linked in a variety of contexts. To provide some illustrative empirical results, reference is made to the Philippine Migration Study (PMS), a research project which incorporates both internal and international migration in its research design. The study examined migration from Ilocos Norte to the principal internal destination, Manila, and the principal international destination, Honolulu. Ilocos Norte is a largely rural, resource poor province with a long history of outmigration that is attributable primarily to population pressure in the region. Due to the fact that 1 of the principal migration streams from the Ilocos is within the Philippines and the other is outside the country, the Ilocos presents an ideal situation for a comparative analysis of internal and international migration. The study consists of 7 different surveys conducted in Ilocos Norte, Manila, and Honolulu between 1980-83. More than 5000 interviews were conducted in the 3 locations. The initial baseline survey in Ilocos Norte was conducted in 1980. After 2-1/2 years, the initial 830 households in the Ilocos Baseline Survey were recontacted to determine the migration behavior of the household members since the 1st survey. Those who had moved to either Manila or Hawaii during this period were traced to the destination and interviewed there. The PMS uses a single integrated model (the value-expectancy or VE framework) to explore migration decision making for both internal and external migration. Despite the complexity of the VE questions, respondents were able to distinguish different locations as being relatively good places or bad places to realize their different goals. Manila was not highly regarded by Ilocanos in most respects, and there was not a single value on which Manila ranked higher than both alternative locations. Relative to the other values, however, Manila is seen as being a good place for educational opportunities and entertainment. Hawaii rated very well on items having to do with wealth and status, but was regarded as a relatively poor place to satisfy one's desire for affiliation. Comfort, affiliation, and morality were viewed as being most easily achieved in the present barangay. Based upon the value-expectancy framework, the findings of the Philippine Migration Study confirm that a global model of migration decision making is feasible and that other important concepts in migration equally apply well in the case of both internal and international population movements.     

Evidence-based practice knowledge and utilization among social workers

In this study the researchers examined the knowledge, skills, and use of Evidence-Based Practice in a sample of social workers from different practice settings. Using an electronic survey, data were collected from a group of social work practitioners (N = 200). Participants in their 30s and 40s demonstrated the most knowledge and use of Evidence-Based Practice. In addition, a high percentage of social workers reported to be knowledgeable about social work research databases; a smaller percentage actually used online resources in their practice. Through this study the researchers add to what is currently known about social workers' perceptions, knowledge, and use of Evidence-Based Practice.     

Dropping the ball on media inquiries: The role of deadlines in media catching

Deadlines have always played a significant role in the practice of public relations, especially the media relations specialization. Public relations textbooks and practitioner handbooks encourage budding practitioners to learn how and when journalists, broadcasters, and Internet authors work so that they may pitch story ideas to them appropriately. Even though media catching, an emerging trend in media relations, reverses the traditional direction of story pitching, deadlines are still critical for this new media relations approach. Through a content analysis of 2802 Help-A-Reporter-Out media requests, this study examines how deadlines vary among media outlets engaging in this new media relations story. Statistically significant differences provide insights for public relations practitioners as to how they can best utilize the service to compete for media placements.