2,652 research outputs found

    A comparison of the in vitro and in planta responses of Phytophthora cinnamomi isolates to phosphite

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    Research in plant pathology often relies on testing interactions between a fungicide and a pathogen in vitro and extrapolating from these results what may happen in planta. Likewise, results from glasshouse experiments are used to estimate what will happen if the fungicide is applied in the field. However, it is difficult to obtain conditions in vitro and in the glasshouse which reflect the conditions where the fungicide may eventually be used, in the field. The aim of this paper is to compare results of the effect of phosphite on P. cinnamomi isolates in vitro and in planta

    Oxygen Fugacity of the Upper Mantle of Mars. Evidence from the Partitioning Behavior of Vanadium in Y980459 (Y98) and other Olivine-Phyric Shergottites

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    Using partitioning behavior of V between olivine and basaltic liquid precisely calibrated for martian basalts, we determined the redox state of primitive (olivine-rich, high Mg#) martian basalts near their liquidus. The combination of oxidation state and incompatible element characteristics determined from early olivine indicates that correlations between fO2 and other geochemical characteristics observed in many martian basalts is also a fundamental characteristic of these primitive magmas. However, our data does not exhibit the range of fO2 observed in these previous studies.. We conclude that the fO2 for the martian upper mantle is approximately IW+1 and is incompatible-element depleted. It seems most likely (although clearly open to interpretation) that these mantle-derived magmas assimilated a more oxidizing (>IW+3), incompatible-element enriched, lower crustal component as they ponded at the base of the martian crust

    Effect of Sulfur on Siderophile Element Partitioning Between Olivine and Martian Primary Melt

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    Since olivine is a common early crystallizing phase in basaltic magmas that have produced planetary and asteroidal crusts, a number of experimental studies have investigated elemental partitioning between olivine and silicate melt [e.g., 1, 2, 3]. In particular, olivine/melt partition coefficients of Ni and Co (DNi and DCo) have been intensively studied because these elements are preferentially partitioned into olivine and thus provide a uniquely useful insight into the basalt petrogenesis [e.g., 4, 5]. However, none of these experimental studies are consistent with incompatible signatures of Co [e.g., 6, 7, 8] and Ni [7] in olivines from Martian meteorites. Chemical analyses of undegassed MORB samples suggest that S dissolved in silicate melts can reduce DNi up to 50 % compared to S-free experimental systems [9]. High S solubility (up to 4000 ppm) for primitive shergottite melts [10] implies that S might have significantly influenced the Ni and Co partitioning into shergottite olivines. This study conducts melting experiments on Martian magmatic conditions to investigate the effect of S on the partitioning of siderophile elements between olivine and Martian primary melt

    The evolution of bits and bottlenecks in a scientific workflow trying to keep up with technology: Accelerating 4D image segmentation applied to nasa data

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    In 2016, a team of earth scientists directly engaged a team of computer scientists to identify cyberinfrastructure (CI) approaches that would speed up an earth science workflow. This paper describes the evolution of that workflow as the two teams bridged CI and an image segmentation algorithm to do large scale earth science research. The Pacific Research Platform (PRP) and The Cognitive Hardware and Software Ecosystem Community Infrastructure (CHASE-CI) resources were used to significantly decreased the earth science workflow's wall-clock time from 19.5 days to 53 minutes. The improvement in wall-clock time comes from the use of network appliances, improved image segmentation, deployment of a containerized workflow, and the increase in CI experience and training for the earth scientists. This paper presents a description of the evolving innovations used to improve the workflow, bottlenecks identified within each workflow version, and improvements made within each version of the workflow, over a three-year time period

    The Expression and Roles of Nde1 and Ndel1 in the Adult Mammalian Central Nervous System

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    Open Access funded by Wellcome Trust Under a Creative Commons license Acknowledgments We thank Prof Angelo Sementilli, Department of Pathology, Universidade Metropolitana de Santos, SP, Brazil, for the human sample collection. This study is funded by Scottish Universities Life Sciences Alliance (HR07019 to S. Shen and C.D. McCaig), Medical Research Scotland (384 FRG to B. Lang, United Kingdom), Tenovus Scotland (G12/25 to B. Lang), Sino-UK Higher Education Research Partnership for PhD Studies (C.D. McCaig and Y.Q. Ding) and Wellcome Trust (WT081633MA-NCE to P.J.A. McCaffery, United Kingdom).Peer reviewedPublisher PD

    Environmental and Botanical Controls on Peatification - A Comparative Study of Two New Zealand Restiad Bogs Using Py-GC/MS, Petrography and Fungal Analysis

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    This study shows that chemical properties of two restiad species, Empodisma minus and Sporadanthus traversii, may contribute to their success as peat-formers in a climate of the North Island of New Zealand which is not conducive to raised mire development. Unlike Sphagnum, the equivalent northern hemisphere peat-former, restiads possess lignin in their tissues. In addition, the presence of non-lignin polyphenols (including tannins and phenolic acids) in restiads may be an important factor in peat formation due to the allelopathic decay retardation. Patterns of degradation of plant biopolymers have been examined and the pathway of degradation of monocotyledons (loss of non-lignin phenolic fraction, depolymerization via modification of side chains of -O-4 lignin, depletion of hemicelluloses) was identified. Trends in chemical change for lignin were not necessarily paralleled by a similar change in the degree of plant structure preservation—an expression of a complex nature of degradation involving the contributions of several processes affecting different classes of biopolymers to different extents. A further finding of this study is that the degree of lignin breakdown, together with proportions of fungal hyphae and petrographic character, indicate that one of the two bogs studied, Moanatuatua, has undergone far more aerobic decay throughout its development than has its climatic and vegetational equivalent, Kopouatai. This is thought to be due to differing water tables in the two sedimentary environments. Moanatuatua developed in a flood plain distant from the sea with a migrating river system, while Kopouatai developed near the sea. A high degree of natural peat decomposition at Moanatuatua most probably precluded any further rapid decay after recent agricultural drainage

    The architecture and ppGpp-dependent expression of the primary transcriptome of Salmonella Typhimurium during invasion gene expression

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    <p>Abstract</p> <p>Background</p> <p>Invasion of intestinal epithelial cells by <it>Salmonella enterica </it>serovar Typhimurium (<it>S</it>. Typhimurium) requires expression of the extracellular virulence gene expression programme (ST<sup>EX</sup>), activation of which is dependent on the signalling molecule guanosine tetraphosphate (ppGpp). Recently, next-generation transcriptomics (RNA-seq) has revealed the unexpected complexity of bacterial transcriptomes and in this report we use differential RNA sequencing (dRNA-seq) to define the high-resolution transcriptomic architecture of wild-type <it>S</it>. Typhimurium and a ppGpp null strain under growth conditions which model ST<sup>EX</sup>. In doing so we show that ppGpp plays a much wider role in regulating the <it>S</it>. Typhimurium ST<sup>EX </sup>primary transcriptome than previously recognised.</p> <p>Results</p> <p>Here we report the precise mapping of transcriptional start sites (TSSs) for 78% of the <it>S</it>. Typhimurium open reading frames (ORFs). The TSS mapping enabled a genome-wide promoter analysis resulting in the prediction of 169 alternative sigma factor binding sites, and the prediction of the structure of 625 operons. We also report the discovery of 55 new candidate small RNAs (sRNAs) and 302 candidate antisense RNAs (asRNAs). We discovered 32 ppGpp-dependent alternative TSSs and determined the extent and level of ppGpp-dependent coding and non-coding transcription. We found that 34% and 20% of coding and non-coding RNA transcription respectively was ppGpp-dependent under these growth conditions, adding a further dimension to the role of this remarkable small regulatory molecule in enabling rapid adaptation to the infective environment.</p> <p>Conclusions</p> <p>The transcriptional architecture of <it>S</it>. Typhimurium and finer definition of the key role ppGpp plays in regulating <it>Salmonella </it>coding and non-coding transcription should promote the understanding of gene regulation in this important food borne pathogen and act as a resource for future research.</p
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