162 research outputs found

    Stream ecosystem responses to an extreme rainfall event across multiple catchments in southeast Alaska

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    Floods are a key component of the flow regime of many rivers and a major structuring force of stream communities. Climate change is predicted to increase the frequency of extreme rainfall (i.e. return intervals > 100 years) leading to extensive flooding, but the ecological effects of such events are not well understood. Comparative studies of flood impacts are scarce, despite the clear need to understand the potentially contingent responses of multiple independent stream systems to extreme weather occurring at meso- and synoptic spatial scales. We describe the effect of an extreme rainfall event affecting an area >100,000 km2 that caused extensive flooding in SE Alaska. Responses of channel morphology and three key biological groups (meiofauna, macroinvertebrates and fish) were assessed in four separate and recently deglaciated stream catchments of contrasting age (38-180 years) by comparing samples taken before and after the event. Ecological responses to the rainfall and subsequent flooding differed markedly across the four catchments in response to variations in rainfall intensity and to factors such as channel morphology, stream sediment composition and catchment vegetation type and cover, which were themselves related to stream age. Our study demonstrates the value of considering multiple response variables when assessing the effects of extreme events, and highlights the potential for contrasting biological responses to extreme events across catchments. We advocate more comparative studies to understand how extreme rainfall and flooding affects ecosystem responses across multiple catchments

    Suspects' consistency in statements concerning two events when different question formats are used.

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    Lie detection research has typically focused on reports about a single event. However, in many forensic and security contexts, suspects are likely to report on several events, some of them may be untruthful. This presents interviewers with the challenge of detecting which reports are true and which are not. Varying question format in a second interview, we examined differences in liars' and truth-tellers' statement consistency about two events. One hundred and fifty participants viewed a meeting in which a noncritical and a critical event were discussed. Truth-tellers were instructed to be honest in their reports about both events, whereas liars had to lie about the critical event. In the first interview, all participants provided a free recall account. In a second interview, participants either gave another free recall account or responded to specific questions presented sequentially (concerning one event at a time) or nonsequentially (concerning both events simultaneously). Liars' accounts featured fewer repetitions than truth-tellers for both events, particularly in response to questions presented in nonsequential order. The implications for the use of this question format are discussed

    Power and limitations of electrophoretic separations in proteomics strategies

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    Proteomics can be defined as the large-scale analysis of proteins. Due to the complexity of biological systems, it is required to concatenate various separation techniques prior to mass spectrometry. These techniques, dealing with proteins or peptides, can rely on chromatography or electrophoresis. In this review, the electrophoretic techniques are under scrutiny. Their principles are recalled, and their applications for peptide and protein separations are presented and critically discussed. In addition, the features that are specific to gel electrophoresis and that interplay with mass spectrometry (i.e., protein detection after electrophoresis, and the process leading from a gel piece to a solution of peptides) are also discussed

    Repertoire of microRNAs in Epithelial Ovarian Cancer as Determined by Next Generation Sequencing of Small RNA cDNA Libraries

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    MicroRNAs (miRNAs) are small regulatory RNAs that are implicated in cancer pathogenesis and have recently shown promise as blood-based biomarkers for cancer detection. Epithelial ovarian cancer is a deadly disease for which improved outcomes could be achieved by successful early detection and enhanced understanding of molecular pathogenesis that leads to improved therapies. A critical step toward these goals is to establish a comprehensive view of miRNAs expressed in epithelial ovarian cancer tissues as well as in normal ovarian surface epithelial cells.We used massively parallel pyrosequencing (i.e., "454 sequencing") to discover and characterize novel and known miRNAs expressed in primary cultures of normal human ovarian surface epithelium (HOSE) and in tissue from three of the most common histotypes of ovarian cancer. Deep sequencing of small RNA cDNA libraries derived from normal HOSE and ovarian cancer samples yielded a total of 738,710 high-quality sequence reads, generating comprehensive digital profiles of miRNA expression. Expression profiles for 498 previously annotated miRNAs were delineated and we discovered six novel miRNAs and 39 candidate miRNAs. A set of 124 miRNAs was differentially expressed in normal versus cancer samples and 38 miRNAs were differentially expressed across histologic subtypes of ovarian cancer. Taqman qRT-PCR performed on a subset of miRNAs confirmed results of the sequencing-based study.This report expands the body of miRNAs known to be expressed in epithelial ovarian cancer and provides a useful resource for future studies of the role of miRNAs in the pathogenesis and early detection of ovarian cancer

    A theoretical model for the development of a diagnosis-based clinical decision rule for the management of patients with spinal pain

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    Accelerating Live Single-Cell Signalling Studies.

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    The dynamics of signalling networks that couple environmental conditions with cellular behaviour can now be characterised in exquisite detail using live single-cell imaging experiments. Recent improvements in our abilities to introduce fluorescent sensors into cells, coupled with advances in pipelines for quantifying and extracting single-cell data, mean that high-throughput systematic analyses of signalling dynamics are becoming possible. In this review, we consider current technologies that are driving progress in the scale and range of such studies. Moreover, we discuss novel approaches that are allowing us to explore how pathways respond to changes in inputs and even predict the fate of a cell based upon its signalling history and state
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