615 research outputs found

    Phylogeography of Austral soil invertebrates

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    Soil invertebrates are terrestrial animals belonging to ancient phyla that emerged almost half a billion years ago. They have since spread throughout all known landmasses, with contemporary distributions governed by geological and environmental change across spatial and temporal gradients across the globe. However, limited knowledge of southern hemisphere (Austral) species hampers our ability to discern the general patterns of distribution and speciation. The lack of robust taxonomic information has also constrained our understanding of the evolutionary relationships and functional roles of the diverse soil fauna. This thesis capitalises on the development in molecular tools and improved sequence libraries to explore the factors that define the distribution and diversity of common soil invertebrates, specifically oribatid mites (Acari), springtails (Collembola) and nematodes (Nematoda). I investigated communities at continental-scales from maritime Antarctica and Australia to enable greater resolution of the drivers of distribution that might be applicable to southern hemisphere taxa more broadly. In a literature review I introduce the bioinformatic approaches using phylogeography to resolve evolutionary theories concerning soil fauna indigenous to Antarctica. Phylogenetic evidence supports most soil faunal groups as having ancient origins, refugial survival and repeated colonisation, whilst also highlighting the benefits of comparative analyses over larger scales. In addition, I show in a perspectives paper that morphological and functional traits are phylogenetically constrained in nematodes and springtails, allowing function to be partially conferred for ‘unknown’ species using sequencing approaches. Baseline biodiversity across a transect through maritime Antarctica found contrasting distributions of mites and springtails and the influences of climatic factors at broad scales and soil microhabitat conditions at local scales. Detailed population genetic analysis of genotypes of the oribatid mites Podacarus auberti and Membranoppia loxolineata alongside the springtail Cryptopygus antarcticus revealed the importance of multiple dispersal events in their ancestral past, supporting theories of refugial survival. Comparative analysis of phylogeographic reconstructions with an analogous Australian transect highlighted that the importance of dispersal differs among mites and springtails and supported the influences of climate and edaphic factors on assemblage structure. These different influences of biogeography and climatic variability related to inherent morphological and physiological traits of the study organisms demonstrate potentially contrasting responses to future episodes of environmental change. With such knowledge, conservation strategies of Austral soil fauna can be re-focussed to ensure their continued persistence in terrestrial ecosystems

    Factors influencing community case management and care hours for clients with traumatic brain injury living in the UK

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    Objective: To investigate the relationship between deficits associated with traumatic brain injury (TBI) and case management (CM) and care/support (CS) in two UK community samples. Research design: Prospective descriptive study. Method: Case managers across the UK and from a single UK CM service contributed client profiles to two data sets (Groups 1 and 2, respectively). Data were entered on demographics, injury severity, functional skills, functional-cognition (including executive functions), behaviour and CM and CS hours. Relationships were explored between areas of disability and service provision. Results: Clients in Group 2 were more severely injured, longer post-injury and had less family support than clients in Group 1. There were few significant differences between Groups 1 and 2 on measures of Functionalskill, Functional-cognition and Behaviour disorder. Deficits in Functionalskills were associated with CS, but not CM. Deficits in measures of executive functions (impulsivity, predictability, response to direction) were related to CM, but not to CS. Insight was related to both CM and CS. Variables related to behaviour disorder were related to CM, but were less often correlated to CS. Conclusions: The need for community support is related not only to Functionalskills (CS), but also to behaviour disorder, self-regulatory skills and impaired insight (CM)

    Training the workforce in evidence-based public health: An evaluation of impact among US and international practitioners

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    INTRODUCTION: The Prevention Research Center in St. Louis developed a course on evidence-based public health in 1997 to train the public health workforce in implementation of evidence-based public health. The objective of this study was to assess use and benefits of the course and identify barriers to using evidence-based public health skills as well as ways to improve the course. METHODS: We used a mixed-method design incorporating on-site pre- and post-evaluations among US and international course participants who attended from 2008 through 2011 and web-based follow-up surveys among course participants who attended from 2005 through 2011 (n = 626). Respondents included managers, specialists, and academics at state health departments, local health departments, universities, and national/regional health departments. RESULTS: We found significant improvement from pre- to post-evaluation for 11 measures of knowledge, skill, and ability. Follow-up survey results showed at least quarterly use of course skills in most categories, majority endorsement of most course benefits, and lack of funding and coworkers who do not have evidence-based public health training as the most significant barriers to implementation of evidence-based public health. Respondents suggested ways to increase evidence-based decision making at their organization, focusing on organizational support and continued access to training. CONCLUSION: Although the evidence-based public health course is effective in improving self-reported measures of knowledge, skill, and ability, barriers remain to the implementation of evidence-based decision making, demonstrating the importance of continuing to offer and expand training in evidence-based public health

    Twitter-based analysis of the dynamics of collective attention to political parties

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    Large-scale data from social media have a significant potential to describe complex phenomena in real world and to anticipate collective behaviors such as information spreading and social trends. One specific case of study is represented by the collective attention to the action of political parties. Not surprisingly, researchers and stakeholders tried to correlate parties' presence on social media with their performances in elections. Despite the many efforts, results are still inconclusive since this kind of data is often very noisy and significant signals could be covered by (largely unknown) statistical fluctuations. In this paper we consider the number of tweets (tweet volume) of a party as a proxy of collective attention to the party, identify the dynamics of the volume, and show that this quantity has some information on the elections outcome. We find that the distribution of the tweet volume for each party follows a log-normal distribution with a positive autocorrelation of the volume over short terms, which indicates the volume has large fluctuations of the log-normal distribution yet with a short-term tendency. Furthermore, by measuring the ratio of two consecutive daily tweet volumes, we find that the evolution of the daily volume of a party can be described by means of a geometric Brownian motion (i.e., the logarithm of the volume moves randomly with a trend). Finally, we determine the optimal period of averaging tweet volume for reducing fluctuations and extracting short-term tendencies. We conclude that the tweet volume is a good indicator of parties' success in the elections when considered over an optimal time window. Our study identifies the statistical nature of collective attention to political issues and sheds light on how to model the dynamics of collective attention in social media.Comment: 16 pages, 7 figures, 3 tables. Published in PLoS ON

    Complex patterns of human antisera reactivity to novel 2009 H1N1 and historical H1N1 influenza strains

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    Background: During the 2009 influenza pandemic, individuals over the age of 60 had the lowest incidence of infection with approximately 25% of these people having pre-existing, cross-reactive antibodies to novel 2009 H1N1 influenza isolates. It was proposed that older people had pre-existing antibodies induced by previous 1918-like virus infection(s) that cross-reacted to novel H1N1 strains. Methodology/Principal Findings: Using antisera collected from a cohort of individuals collected before the second wave of novel H1N1 infections, only a minority of individuals with 1918 influenza specific antibodies also demonstrated hemagglutination-inhibition activity against the novel H1N1 influenza. In this study, we examined human antisera collected from individuals that ranged between the ages of 1 month and 90 years to determine the profile of seropositive influenza immunity to viruses representing H1N1 antigenic eras over the past 100 years. Even though HAI titers to novel 2009 H1N1 and the 1918 H1N1 influenza viruses were positively associated, the association was far from perfect, particularly for the older and younger age groups. Conclusions/Significance: Therefore, there may be a complex set of immune responses that are retained in people infected with seasonal H1N1 that can contribute to the reduced rates of H1N1 influenza infection in older populations. © 2012 Carter et al

    Integrated genomics and proteomics define huntingtin CAG length-dependent networks in mice.

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    To gain insight into how mutant huntingtin (mHtt) CAG repeat length modifies Huntington's disease (HD) pathogenesis, we profiled mRNA in over 600 brain and peripheral tissue samples from HD knock-in mice with increasing CAG repeat lengths. We found repeat length-dependent transcriptional signatures to be prominent in the striatum, less so in cortex, and minimal in the liver. Coexpression network analyses revealed 13 striatal and 5 cortical modules that correlated highly with CAG length and age, and that were preserved in HD models and sometimes in patients. Top striatal modules implicated mHtt CAG length and age in graded impairment in the expression of identity genes for striatal medium spiny neurons and in dysregulation of cyclic AMP signaling, cell death and protocadherin genes. We used proteomics to confirm 790 genes and 5 striatal modules with CAG length-dependent dysregulation at the protein level, and validated 22 striatal module genes as modifiers of mHtt toxicities in vivo

    Measurement of the branching fraction for ΄(1S)→τ+τ−\Upsilon (1S) \to \tau^+ \tau^-

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    We have studied the leptonic decay of the ΄(1S)\Upsilon (1S) resonance into tau pairs using the CLEO II detector. A clean sample of tau pair events is identified via events containing two charged particles where exactly one of the particles is an identified electron. We find B(΄(1S)→τ+τ−)=(2.61 ± 0.12 +0.09−0.13)B(\Upsilon(1S) \to \tau^+ \tau^-) = (2.61~\pm~0.12~{+0.09\atop{-0.13}})%. The result is consistent with expectations from lepton universality.Comment: 9 pages, RevTeX, two Postscript figures available upon request, CLNS 94/1297, CLEO 94-20 (submitted to Physics Letters B

    The homocysteine controversy

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    Mild to moderate hyperhomocysteinemia has been identified as a strong predictor of cardiovascular disease, independent from classical atherothrombotic risk factors. In the last decade, a number of large intervention trials using B vitamins have been performed and have shown no benefit of homocysteine-lowering therapy in high-risk patients. In addition, Mendelian randomization studies failed to convincingly demonstrate that a genetic polymorphism commonly associated with higher homocysteine levels (methylenetetrahydrofolate reductase 677 C>T) is a risk factor for cardiovascular disease. Together, these findings have cast doubt on the role of homocysteine in cardiovascular disease pathogenesis, and the homocysteine hypothesis has turned into a homocysteine controversy. In this review, we attempt to find solutions to this controversy. First, we explain that the Mendelian randomization analyses have limitations that preclude final conclusions. Second, several characteristics of intervention trials limit interpretation and generalizability of their results. Finally, the possibility that homocysteine lowering is in itself beneficial but is offset by adverse side effects of B vitamins on atherosclerosis deserves serious attention. As we explain, such side effects may relate to direct adverse effects of the B-vitamin regimen (in particular, the use of high-dose folic acid) or to proinflammatory and proproliferative effects of B vitamins on advanced atherosclerotic lesions

    Fine-mapping identifies multiple prostate cancer risk loci at 5p15, one of which associates with TERT expression

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    Associations between single nucleotide polymorphisms (SNPs) at 5p15 and multiple cancer types have been reported. We have previously shown evidence for a strong association between prostate cancer (PrCa) risk and rs2242652 at 5p15, intronic in the telomerase reverse transcriptase (TERT) gene that encodes TERT. To comprehensively evaluate the association between genetic variation across this region and PrCa, we performed a fine-mapping analysis by genotyping 134 SNPs using a custom Illumina iSelect array or Sequenom MassArray iPlex, followed by imputation of 1094 SNPs in 22 301 PrCa cases and 22 320 controls in The PRACTICAL consortium. Multiple stepwise logistic regression analysis identified four signals in the promoter or intronic regions of TERT that independently associated with PrCa risk. Gene expression analysis of normal prostate tissue showed evidence that SNPs within one of these regions also associated with TERT expression, providing a potential mechanism for predisposition to disease
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