64 research outputs found

    Phytoplankton Dynamics of Two North Carolina Coastal Plain Swamps: Species Composition, Seasonal Periodicity and Impact of Wastewater Discharge

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    INTRODUCTION: Wetland Values: Wetlands are valuable ecosystems which serve to interface land and water systems. Saturation of the soil and type of vegetation are major criteria which define wetlands (Cowardin, et al. 1979). These ecosystems support diverse plant and animal communities and the magnitude of primary productivity in wetlands is of global importance. In addition, wetlands provide sanctuary to many threatened and endangered species of plants and animals. Wetland ecosystems also have many valuable hydrologic functions. In palustrine forested wetlands, commonly called swamps, the inundation of the soil varies with the season and the amount of precipitation and runoff. One of the predominant values of wetlands is their capacity to serve as sites of water retention and flood control. They are also traps for suspended sediments and nutrients, thus improving the water quality downstream (Carter, et al.,1979). Because of their potential to improve water quality, wetlands have also been used as tertiary treatment for municipal wastewater discharge (Brinson and Westall, 1983; Richardson and Nichols, 1986), However, such uses are inappropriate if using the wetland as a site for sewage treatment will alter the valuable ecologic and hydrologic functions of the wetland.Master of Science in Public Healt

    Designing and using incentives to support recruitment and retention in clinical trials:a scoping review and a checklist for design

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    BACKGROUND: Recruitment and retention of participants are both critical for the success of trials, yet both remain significant problems. The use of incentives to target participants and trial staff has been proposed as one solution. The effects of incentives are complex and depend upon how they are designed, but these complexities are often overlooked. In this paper, we used a scoping review to 'map' the literature, with two aims: to develop a checklist on the design and use of incentives to support recruitment and retention in trials; and to identify key research topics for the future.METHODS: The scoping review drew on the existing economic theory of incentives and a structured review of the literature on the use of incentives in three healthcare settings: trials, pay for performance, and health behaviour change. We identified the design issues that need to be considered when introducing an incentive scheme to improve recruitment and retention in trials. We then reviewed both the theoretical and empirical evidence relating to each of these design issues. We synthesised the findings into a checklist to guide the design of interventions using incentives.RESULTS: The issues to consider when designing an incentive system were summarised into an eight-question checklist. The checklist covers: the current incentives and barriers operating in the system; who the incentive should be directed towards; what the incentive should be linked to; the form of incentive; the incentive size; the structure of the incentive system; the timing and frequency of incentive payouts; and the potential unintended consequences. We concluded the section on each design aspect by highlighting the gaps in the current evidence base.CONCLUSIONS: Our findings highlight how complex the design of incentive systems can be, and how crucial each design choice is to overall effectiveness. The most appropriate design choice will differ according to context, and we have aimed to provide context-specific advice. Whilst all design issues warrant further research, evidence is most needed on incentives directed at recruiters, optimal incentive size, and testing of different incentive structures, particularly exploring repeat arrangements with recruiters.</p

    Heterochromatic sequences in a Drosophila whole-genome shotgun assembly

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    BACKGROUND: Most eukaryotic genomes include a substantial repeat-rich fraction termed heterochromatin, which is concentrated in centric and telomeric regions. The repetitive nature of heterochromatic sequence makes it difficult to assemble and analyze. To better understand the heterochromatic component of the Drosophila melanogaster genome, we characterized and annotated portions of a whole-genome shotgun sequence assembly. RESULTS: WGS3, an improved whole-genome shotgun assembly, includes 20.7 Mb of draft-quality sequence not represented in the Release 3 sequence spanning the euchromatin. We annotated this sequence using the methods employed in the re-annotation of the Release 3 euchromatic sequence. This analysis predicted 297 protein-coding genes and six non-protein-coding genes, including known heterochromatic genes, and regions of similarity to known transposable elements. Bacterial artificial chromosome (BAC)-based fluorescence in situ hybridization analysis was used to correlate the genomic sequence with the cytogenetic map in order to refine the genomic definition of the centric heterochromatin; on the basis of our cytological definition, the annotated Release 3 euchromatic sequence extends into the centric heterochromatin on each chromosome arm. CONCLUSIONS: Whole-genome shotgun assembly produced a reliable draft-quality sequence of a significant part of the Drosophila heterochromatin. Annotation of this sequence defined the intron-exon structures of 30 known protein-coding genes and 267 protein-coding gene models. The cytogenetic mapping suggests that an additional 150 predicted genes are located in heterochromatin at the base of the Release 3 euchromatic sequence. Our analysis suggests strategies for improving the sequence and annotation of the heterochromatic portions of the Drosophila and other complex genomes

    Fine mapping of a linkage peak with integration of lipid traits identifies novel coronary artery disease genes on chromosome 5

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    Coronary artery disease (CAD), and one of its intermediate risk factors, dyslipidemia, possess a demonstrable genetic component, although the genetic architecture is incompletely defined. We previously reported a linkage peak on chromosome 5q31-33 for early-onset CAD where the strength of evidence for linkage was increased in families with higher mean low density lipoprotein-cholesterol (LDL-C). Therefore, we sought to fine-map the peak using association mapping of LDL-C as an intermediate disease-related trait to further define the etiology of this linkage peak. The study populations consisted of 1908 individuals from the CATHGEN biorepository of patients undergoing cardiac catheterization; 254 families (N = 827 individuals) from the GENECARD familial study of early-onset CAD; and 162 aorta samples harvested from deceased donors. Linkage disequilibrium-tagged SNPs were selected with an average of one SNP per 20 kb for 126.6-160.2 MB (region of highest linkage) and less dense spacing (one SNP per 50 kb) for the flanking regions (117.7-126.6 and 160.2-167.5 MB) and genotyped on all samples using a custom Illumina array. Association analysis of each SNP with LDL-C was performed using multivariable linear regression (CATHGEN) and the quantitative trait transmission disequilibrium test (QTDT; GENECARD). SNPs associated with the intermediate quantitative trait, LDL-C, were then assessed for association with CAD (i.e., a qualitative phenotype) using linkage and association in the presence of linkage (APL; GENECARD) and logistic regression (CATHGEN and aortas)

    Finishing the euchromatic sequence of the human genome

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    The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

    Death penalty: the political foundations of the global trend toward abolition

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    The death penalty is like no other punishment. Its continued existence in many countries of the world creates political tensions within these countries and between governments of retentionist and abolitionist countries. After the Second World War, more and more countries have abolished the death penalty. This article argues that the major determinants of this global trend toward abolition are political, a claim which receives support in a quantitative cross-national analysis from 1950 to 2002. Democracy, democratization, international political pressure on retentionist countries and peer group effects in relatively abolitionist regions all raise the likelihood of abolition. There is also a partisan effect as abolition becomes more likely if the chief executive’s party is left-wing oriented. Cultural, social and economic determinants receive only limited support. The global trend toward abolition will go on if democracy continues to spread around the world and abolitionist countries stand by their commitment to press for abolition all over the world.

    Fine mapping of a linkage peak with integration of lipid traits identifies novel coronary artery disease genes on chromosome 5

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    Background: Coronary artery disease (CAD), and one of its intermediate risk factors, dyslipidemia, possess a demonstrable genetic component, although the genetic architecture is incompletely defined. We previously reported a linkage peak on chromosome 5q31-33 for early-onset CAD where the strength of evidence for linkage was increased in families with higher mean low density lipoprotein-cholesterol (LDL-C). Therefore, we sought to fine-map the peak using association mapping of LDL-C as an intermediate disease-related trait to further define the etiology of this linkage peak. The study populations consisted of 1908 individuals from the CATHGEN biorepository of patients undergoing cardiac catheterization; 254 families (N = 827 individuals) from the GENECARD familial study of early-onset CAD; and 162 aorta samples harvested from deceased donors. Linkage disequilibrium-tagged SNPs were selected with an average of one SNP per 20 kb for 126.6-160.2 MB (region of highest linkage) and less dense spacing (one SNP per 50 kb) for the flanking regions (117.7-126.6 and 160.2-167.5 MB) and genotyped on all samples using a custom Illumina array. Association analysis of each SNP with LDL-C was performed using multivariable linear regression (CATHGEN) and the quantitative trait transmission disequilibrium test (QTDT; GENECARD). SNPs associated with the intermediate quantitative trait, LDL-C, were then assessed for association with CAD (i.e., a qualitative phenotype) using linkage and association in the presence of linkage (APL; GENECARD) and logistic regression (CATHGEN and aortas).Results: We identified four genes with SNPs that showed the strongest and most consistent associations with LDL-C and CAD: EBF1, PPP2R2B, SPOCK1, and PRELID2. The most significant results for association of SNPs with LDL-C were: EBF1, rs6865969, p = 0.01; PPP2R2B, rs2125443, p = 0.005; SPOCK1, rs17600115, p = 0.003; and PRELID2, rs10074645, p = 0.0002). The most significant results for CAD were EBF1, rs6865969, p = 0.007; PPP2R2B, rs7736604, p = 0.0003; SPOCK1, rs17170899, p = 0.004; and PRELID2, rs7713855, p = 0.003.Conclusion: Using an intermediate disease-related quantitative trait of LDL-C we have identified four novel CAD genes, EBF1, PRELID2, SPOCK1, and PPP2R2B. These four genes should be further examined in future functional studies as candidate susceptibility loci for cardiovascular disease mediated through LDL-cholesterol pathways.</p
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