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At least 1,099 records · Page 61Linked to original sources
PubMed2002

Comparing Clean Water Act Section 316(b) policy options.

This paper develops a comparative framework for policy proposals involving fish protection and Section 316(b) of the Clean Water Act (CWA). Section 316(b) addresses the impingement and entrainment of fish by cooling-water intake structures used principally by steam electric power plants. The framework is motivated by examining the role of adverse environmental impacts (AEIs) in the context of Section 316(b) decision making. AEI is mentioned in Section 316(b), but not defined. While various AEI options have been proposed over the years, none has been formalized through environmental regulations nor universally accepted. Using a multiple values approach from decision analysis, AEIs are characterized as measurement criteria for ecological impacts. Criteria for evaluating AEI options are identified, including modeling and assessment issues, the characterization of ecological value, regulatory implementation, and the treatment of uncertainty. Motivated by the difficulties in defining AEI once and for all, a framework is introduced to compare options for 316(b) decision making. Three simplified policy options are considered, each with a different implicit or explicit AEI approach: (1) a technology-driven rule based on a strict reading of the 316(b) regulatory text, and for which any impingement and entrainment count as AEI, (2) a complementary, open-ended risk-assessment process for estimating population effects with AEI characterized on a site-specific basis, and (3) an intermediate position based on proxy measures such as specially constructed definitions of littoral zone, sensitive habitat, or water body type. The first two proposals correspond roughly to responses provided, respectively, by the Riverkeeper environmental organization and the Utility Water Act Group to the U.S. Environmental Protection Agency (EPA)'s proposed 316(b) new facilities rule of August 2000; the third example is a simplified form of the EPA's proposed August 2000 new facilities rule itself. The simplified policy positions are compared using the three dimensions of the comparative policy framework: (1) the role of CWA philosophy or vision, such as the use of technology-forcing rules, (2) regulatory policy implementation, and (3) the role for scientific information and the knowledge base. Strengths and weaknesses of all three 316(b) policy approaches are identified. The U.S. EPA's final new facilities rule of November 2001 is briefly characterized using the comparative policy framework and used to further illustrate the approach.

Animals↗
PubMed2025

Cross-species phenotypic profiling uncovers functional determinants of bacterial cold shock adaptation.

Temperature shifts impose broad physiological stress, requiring precise and dynamic regulatory programs to restore cellular homeostasis. While the heat shock response is well characterized, the mechanisms underlying cold shock response (CSR) remain less understood. To identify genes critical for cold adaptation, we applied transposon sequencing (Tn-seq) to monitor mutant fitness across the full course of CSR and sustained low-temperature growth in two mesophilic bacteria, Escherichia coli and Bacillus subtilis. In B. subtilis, phenotypic profiling revealed a temporally structured program: membrane fluidity and cell wall remodeling were most critical in the early stage of CSR, whereas post-transcriptional regulation became essential during late-stage recovery to reprogram gene expression and restore growth. Cross-species comparison uncovered both conserved and species-specific mechanisms, with RNA metabolism and ribosome/translation regulators playing broad roles. Specifically, we identified a conserved synergy between two ribosomal RNA methyltransferases, RsmA and RsmH, in promoting cold adaptation. In B. subtilis, mutants lacking these enzymes exhibited significant delay in translation recovery following cold-induced global inhibition. Together, these findings provide a comparative, systems-level view of bacterial cold adaptation and establish a framework for exploring stress responses in pathogens and extremophiles.

Cell envelope↗
PubMed2007

MicroRNAs regulate the expression of the alternative splicing factor nPTB during muscle development.

Alternative pre-mRNA splicing determines many changes in gene expression during development. Two regulators known to control splicing patterns during neuron and muscle differentiation are the polypyrimidine tract-binding protein (PTB) and its neuronal homolog nPTB. These proteins repress certain exons in early myoblasts, but upon differentiation of mature myotubes PTB/nPTB expression is reduced, leading to increased inclusion of their target exons. We show here that the repression of nPTB expression during myoblast differentiation results from its targeting by the muscle-restricted microRNA miR-133. During differentiation of C2C12 myoblasts, nPTB protein but not mRNA expression is strongly reduced, concurrent with the up-regulation of miR-133 and the induction of splicing for several PTB-repressed exons. Introduction of synthetic miR-133 into undifferentiated C2C12 cells leads to a decrease in endogenous nPTB expression. Both the miR-133 and the coexpressed miR-1/206 microRNAs are extremely conserved across animal species, and PTB proteins are predicted targets for these miRNAs in Drosophila, mice, and humans. There are two potential miR-133-responsive elements (MRE) within the nPTB 3' untranslated region (UTR), and a luciferase reporter carrying this 3' UTR is repressed by miR-133 in an MRE-dependent manner. Transfection of locked nucleic acid (LNA) oligonucleotides designed to block the function of miR-133 and miR-1/206 increases expression of nPTB and decreases the inclusion of PTB dependent exons. These results indicate that miR-133 directly down-regulates a key splicing factor during muscle development and establishes a role for microRNAs in the control of a developmentally dynamic splicing program.

3' Untranslated Regions↗
PubMed1986

The metro rating game: what can be learned from the recent migrants?

The authors examine nine indicators of quality of life in the 277 U.S. Standard Metropolitan Statistical Areas (SMSAs) in terms of their impact on the decision to migrate. The factors considered were utilized in the 1985 publication "Places Rated Almanac" and include climate, housing, health care, crime, transportation, education, recreation, arts, and economics. "The purpose of this paper is both to analyze several alternative methods by which the nine 'Places Rated' indicators have been combined in previous studies, and to estimate a new system of weights for combining such indicators from a multivariate model of metropolitan out-migration." In this article, the authors examine out-migration of metropolitan households during the years 1975-1980. "Coefficient estimates from a multivariate model of out-migration form the basis for a ranking of metropolitan areas in the third section. Also included are comparisons among this and other studies of both the implicit weights employed against the 'Places Rated' scores...to derive both overall measures of urban life quality, and how such quality varies by city size."

Americas↗
PubMed1991

Targeted reintegration of expatriate brains into developing countries of origin: the EEC-IOM experience in Central America.

"The present article...reviews the major findings of the end-evaluation of the EEC-IOM project in Central America, the Dominican Republic and Panama, a five-year scheme funded by the Commission of the European Communities (EEC) and implemented by the International Organization for Migration (IOM), to promote a selective and development-oriented return of Latin American professionals to Costa Rica, the Dominican Republic, Honduras, Nicaragua and Panama.... The core objectives of this evaluation, undertaken in September-December 1989, were to assess the project's contribution to local socioeconomic, scientific and technological development through the selective supply of expatriate professionals to developing institutions operating in so-defined priority areas; to identify the returnees' personal reintegration patterns at the professional, socioeconomic and family-related levels; and to measure the project's cost effectiveness." (SUMMARY IN FRE AND SPA)

Americas↗
PubMed1996

Prolonged induction to delivery time in termination of pregnancy using 16, 16-dimethyl-PGE1-methyl ester (gemeprost) for fetuses with a neural tube defect or hydrocephalus.

A retrospective study is reported comparing the induction to delivery interval using gemeprost for termination of pregnancy, in the second trimester, in 3 groups of patients. It was observed that the mean induction to delivery interval was significantly longer in 75 pregnancies where there was a fetus with a neural tube defect and or hydrocephalus (31.7 hours) compared with 88 pregnancies with other fetal abnormalities (19.7 hours) and 84 pregnancies where there was an intrauterine death (11.3 hours). There was also an increase in the requirements for further intervention to obtain delivery in the group with a neural tube defect or hydrocephalus (n = 33) compared with where there was an intrauterine fetal death (n = 4) and other abnormality (n = 14). We believe these results should be considered when counselling patients who have requested termination of pregnancy for fetal abnormalities.

Abortifacient Agents, Nonsteroidal↗
PubMed1995

Fertility management in Taiwanese and African-American women.

This article describes the fertility management experiences of two groups of women that are of cultures close to but different from dominant, mainstream American culture. A discussion of fertility management necessarily must occur within the context of such issues as the values and norms regarding sexual behavior, choice of partners, and childbearing patterns, and the support and resources offered by the social environment.

Black or African American↗
PubMed1992

Adolescent pregnancy prevention strategies used by school nurses.

This survey identified a range of adolescent pregnancy prevention activities used by school nurses in selected Mid-Atlantic public schools. A purposive sample of 224 public school nurses completed the School Nurse Questionnaire adapted from an instrument used previously to survey school nurses. Based on a 54% response rate, a task analysis revealed that respondents performed only one pregnancy prevention activity frequently. A sub-sample of nurses, serving students in grades 6-12, used seven of 21 pregnancy prevention activities frequently. Though nurses did not actually perform the remaining activities, they felt prepared to do so. However, the structure of school nursing services often does not allow adequate time or opportunity to engage in adolescent pregnancy prevention activities.

Adolescent↗
PubMed1992

Adolescent pregnancy options.

The range of pregnancy options available to adolescents each have significant ramifications for future educational and economic achievement. The changing societal context of adolescent pregnancy decision-making are described, and the characteristics of adolescents who choose to terminate their pregnancy, parent their child, or place for adoption are examined. The role of significant others in decision-making and the implications of mandatory parental involvement in pregnancy decision-making is discussed, as well as the roles of schools in promoting the well-being and potential of adolescents considering pregnancy decisions.

Abortion, Induced↗
PubMed2000

Strategies to maximize retention of a sample of young adolescents in a longitudinal evaluation of Healthy & Alive!

The authors implemented strategies to maximize cohort retention to avert loss of statistical power and minimize bias in a longitudinal evaluation of a middle school HIV/STD prevention intervention. A retention rate of 80% of the baseline sample (n = 2,975) at six months and 73% at 18 months was achieved despite high reported rates of student mobility and a major system reorganization in one urban district. The strategies increased retention but did not eliminate differences in demographic characteristics and behaviors between the groups of retained and lost students. Results confirm the need to implement retention strategies early and to maintain them throughout data collection. Information from a tracking data base can be used to prioritize students for follow-up to reduce bias from sample loss.

Adolescent↗
PubMed2006

Deciphering the underlying mechanism of specification and differentiation: the sea urchin gene regulatory network.

The regulatory genome functions as a vast information processor through development. It processes the initial conditions that are set by asymmetric distributions of cellular components in the egg and translates them into the onset of spatially localized specification states. It regulates the timely differential activation of signaling molecules and transcription factors that divide the emerging domains into subdomains. It also governs the activation of groups of differentiation genes, the genes that encode, at the protein level, the functional and the structural properties of a cell type. The sea urchin endomesoderm gene regulatory network provides a window into the different levels of the regulatory apparatus. It demonstrates how the static physical genomic components define functional connections between the various regulatory genes that act together to conduct the dynamical developmental program.

Animals↗
PubMed2003

Genetic programs and responses of neural stem/progenitor cells during demyelination: potential insights into repair mechanisms in multiple sclerosis.

In recent years, it has become evident that the adult mammalian CNS contains a population of neural stem cells (NSCs) described as immature, undifferentiated, multipotent cells, that may be called upon for repair in neurodegenerative and demyelinating diseases. NSCs may give rise to oligodendrocyte progenitor cells (OPCs) and other myelinating cells. This article reviews recent progress in elucidating the genetic programs and dynamics of NSC and OPC proliferation, differentiation, and apoptosis, including the response to demyelination. Emerging knowledge of the molecules that may be involved in such responses may help in the design of future stem cell-based treatment of demyelinating diseases such as multiple sclerosis.

Animals↗
PubMed1997

Female and male sterilization and refertilization in Sweden.

In Sweden, approximately 1,500 men and 7,000 women are sterilized yearly. The frequency varies considerably between regions. The reasons for these differences are not fully known. More women than men are sterilized in Sweden, but a higher proportion of sterilized men undergo refertilization. The object of the study was to analyze counselling routines prior to sterilization, presterilization waiting time, the number of refertilizations performed, the attitudes of the operating departments towards refertilization, and the possible relation between frequency of refertilization and incidence of sterilization. A questionnaire was mailed to all units performing refertilizations and/or sterilizations of mean and women in Sweden (n = 161). The response was 93%. Counselling routines and waiting times before sterilization varied, which influenced the operation's availability. The frequency of refertilizations varied considerably between counties from 0.5 to 5.4 per 100,000 inhabitants. There was no correlation between frequency of sterilizations and refertilizations. The rate of refertilization appears to be determined mostly by the local attitudes of the health authority. The Swedish sterilization law has had a heterogeneous impact in the country.

Adult↗