Duration Adjustment of Acute Exposure Guideline Level Values for Trichloroethylene Using a Physiologically-Based Pharmacokinetic Model

Acute Exposure Guideline Level (AEGL) recommendations are developed for 10-minute, 30-minute, 1-hour, 4-hours, and 8-hours exposure durations and are designated for three levels of severity: AEGL-1 represents concentrations above which acute exposures may cause noticeable discomfort including irritation; AEGL-2 represents concentrations above which acute exposure may cause irreversible health effects or impaired ability to escape; and AEGL-3 represents concentrations above which exposure may cause life-threatening health effects or death. The default procedure for setting AEGL values across durations when applicable data are unavailable involves estimation based on Haber's rule, which has an underlying assumption that cumulative exposure is the determinant of toxicity. For acute exposure to trichloroethylene (TCE), however, experimental data indicate that momentary tissue concentration, and not the cumulative amount of exposure, is important. We employed an alternative approach to duration adjustments in which a physiologically-based pharmacokinetic (PBPK) model was used to predict the arterial blood concentrations [TCE(a)] associated with adverse outcomes appropriate for AEGL-1, -2, or -3-level effects. The PBPK model was then used to estimate the atmospheric concentration that produces equivalent [TCE(a)] at each of the AEGL-specific exposure durations. This approach yielded [TCE(a)] values of 4.89 mg/l for AEGL-1, 18.7 mg/l for AEGL-2, and 310 mg/l for AEGL-3. Duration adjustments based on equivalent target tissue doses should provide similar degrees of toxicity protection at different exposure durations.     

Migration as Social Movement: Voluntary Group Migration and the Crimean Tatar Repatriation

Voluntary group migration occurs when a collectivity reaches a group‐level decision to migrate and does so as a community without external compulsion. Typical examples include collective settler movements and voluntary repatriations of refugee communities. We demonstrate the distinctive characteristics of voluntary group migration that make it hard to analyze with current migration theories, and we develop an initial theoretical framework identifying the conditions that typically produce this type of population flow. Recognizing the collective nature of the mobilization that leads to voluntary group migration, we turn to social movement theory as a source of analytical tools that, in combination with concepts offered by prior migration theories, help us build an initial theory. To illustrate our ideas, we discuss an especially revealing contemporary case: the resettlement of Crimean Tatars to their original homeland.     

Resisting your good intentions: substance‐misusing parents and early intervention to support and monitor children in need

Children from substance‐misusing families face elevated risks in growing up well and safe. Early intervention is an opportunity for local authorities to offer support and keep a watching brief on children's welfare. However, the basis upon which agencies voluntarily engage with families in advance of major problems becoming evident is far from straightforward. This qualitative pilot study in Scotland followed professional decision‐making over 6 months (n = 20 professionals) with a small number of families (n = 6) defined as in need of supportive intervention. This support was allied with an intention to monitor the family situation, which, in these data, appeared to affect the willingness of families to engage with services. As services sought to increase their voluntary oversight, sometimes by threatening escalating involvement, so families by various means appeared to resist it. Successful early intervention is reliant on voluntary family participation and thus requires close attention to means of positive and motivated parental engagement to disarm resistance.     

Multiperiod Models with Capacities in Competitive Supply Chain

This paper considers a supply chain setting where several capacitated suppliers compete for orders from a single retailer in a multiperiod environment. At each period, the retailer places orders to the suppliers in response to the prices they announce. Each supplier has a fixed capacity. We consider a make‐to‐stock setting where the retailer can carry inventory. The retailer faces exogenous, price‐dependent demand. We study the problem using ideas from fluid models. In particular, we (i) analyze when there are pure equilibrium policies in this setting and characterize the structure of these policies; (ii) consider coordination mechanisms; and (iii) present some preliminary computational results. We also consider a modified model that uses option contracts to coordinate the supply chain.     

A review of generalization methods used in empirical social work literature

This article reviews methods currently used for generalization of findings, based on a review of a representative sample of empirical research studies drawn from three major social work research journals: Social Work Research , Journal of Social Service Research , and Research on Social Work Practice , over a 10-year period (1996–2005). Findings revealed a greater discussion of generalizability limitations in comparison with the past, and other types of generalization methods such as conceptual generalizations and qualitative comparisons of study results with those of other studies. Relatively low usage of quantitative comparisons of sample to population and replication procedures was detected. Implications of these trends are discussed and approaches for improvements are explored.     

Reliability of translated measures assessing dating violence among Mexican adolescents

Research on the prevalence and correlates of dating violence in Mexican teens is challenged by the lack of culturally and linguistically appropriate assessment tools. This study modified, translated, and back-translated the Conflict in Adolescent Dating Relationships Inventory (CADRI; Wolfe et al., 2001) and the Attitudes Towards Dating Violence Scales (Price, Byers, & the Dating Violence Research Team, 1999) for Mexican adolescents. Analyses on 307 adolescents (15-18 years old) from Monterrey and Mexicali, Mexico, revealed that most of the translated CADRI subscales and Attitudes Towards Dating Violence Scales had acceptable internal consistency and test-retest reliability coefficients. The study offers some evidence that the measures may be useful in assessing dating violence in Mexican teens.     

A review of generalization methods used in empirical social work literature

This article reviews methods currently used for generalization of findings, based on a review of a representative sample of empirical research studies drawn from three major social work research journals: Social Work Research , Journal of Social Service Research , and Research on Social Work Practice , over a 10-year period (1996–2005). Findings revealed a greater discussion of generalizability limitations in comparison with the past, and other types of generalization methods such as conceptual generalizations and qualitative comparisons of study results with those of other studies. Relatively low usage of quantitative comparisons of sample to population and replication procedures was detected. Implications of these trends are discussed and approaches for improvements are explored.     

Beyond IPAT and Kuznets Curves: Globalization as a Vital Factor in Analysing the Environmental Impact of Socio-Economic Metabolism

We bring the rapidly developing tools for analyzing society's metabolism to the attention of a scientific audience concerned with matters of population and, in a complementary fashion, we draw the attention of material and energy flow analysts to the role of population and population dynamics within their own paradigm. As an analytic framework, we use the classic IPAT-model that relates environmental impact (I), population (P), affluence (A), and technology (T). We relate the IPAT model to the tool commonly used in MFA, so-called environmental Kuznets curves, and re-analyze empirical data from various sources, for both affluent industrial and for developing countries, within these frameworks. We conclude that population and technology seem to dominate over affluence as far as environmental impact is concerned, but that both the IPAT and Kuznets models fail to take into account the intricate interdependencies among different socio-economic systems and the increases in their the economic, material and population exchanges. In effect, both models tend to underestimate the environmental impact and create too optimistic an image of dematerialization in affluent industrial countries.     

Reference database of hematological parameters for growing and aging rats

The normal hematological values in various phases of the rat life provide a valuable guide to researchers and could be useful for experimental works. However, database information available on the literature are incomplete. Aim: This study aimed to present normal hematological parameters of young and aged rats.

Methods: Male and female rats were distributed into seven experimental groups with 1, 2, 3, 6, 12, 18, and 24 months of age. Blood samples taken from the tails were analyzed. Normal hematological values were determined for each age group.

Results: Rats showed a progressive weight gain with advancing age, predominantly after 3 months of life. With advancing age, differences were found on hematological parameters: some of them showed a progressive rise with age and others did not. Hemoglobin levels and hematocrit did not change while the number of circulating red blood cells suffered slight increase.

Conclusion: The present study determined the normal values for absolute and relative hematological parameters in Wistar rats from 2 to 24 months for male and female rats. The results can be used in studies of effects of aging, feeding, and medications on growing and aging rats.