469 research outputs found

    Effects of propagation conditions on radar beam-ground interaction: impact on data quality

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    International audienceA large part of the research in the radar meteorology is devoted to the evaluation of the radar data quality and to the radar data processing. Even when, a set of absolute quality indexes can be produced (like as ground clutter presence, beam blockage rate, distance from radar, etc.), the final product quality has to be determined as a function of the task and of all the processing steps. In this paper the emphasis lies on the estimate of the rainfall at the ground level taking extra care for the correction for ground clutter and beam blockage, that are two main problems affecting radar reflectivity data in complex orography. In this work a combined algorithm is presented that avoids and/or corrects for these two effects. To achieve this existing methods are modified and integrated with the analysis of radar signal propagation in different atmospheric conditions. The atmospheric refractivity profile is retrieved from the nearest in space and time radiosounding. This measured profile is then used to define the `dynamic map' used as a declutter base-field. Then beam blockage correction is applied to the data at the scan elevations computed from this map. Two case studies are used to illustrate the proposed algorithm. One is a summer event with anomalous propagation conditions and the other one is a winter event. The new algorithm is compared to a previous method of clutter removal based only on static maps of clear air and vertical reflectivity continuity test. The improvement in rain estimate is evaluated applying statistical analysis and using rain gauges data. The better scores are related mostly to the ``optimum" choice of the elevation maps, introduced by the more accurate description of the signal propagation. Finally, a data quality indicator is introduced as an output of this scheme. This indicator has been obtained from the general scheme, which takes into account all radar data processing steps

    Oxidation Enthalpies for Reduction of Ceria Surfaces

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    The thermodynamic properties of surface ceria were investigated through equilibrium isotherms determined by flow-titration and coulometric-titration measurements on high-surface-area ceria and ceria supported on La-modified alumina (LA). While the surface area of pure ceria was found to be unstable under redox conditions, the extent of reduction at 873 K and a P(O2) of 1.6x10-26 atm increased with surface area. Because ceria/LA samples were stable, equilibrium isotherms were determined between 873 and 973 K on a 30-wt% ceria sample. Oxidation enthalpies on ceria/LA were found to vary with the extent of reduction, ranging from -500 kJ/mol O2 at low extents of reduction to near the bulk value of -760 kJ/mol O2 at higher extents. To determine whether +3 dopants could affect the oxidation enthalpies for ceria, isotherms were measured for Sm+3-doped ceria (SDC) and Y+3-doped ceria. These dopants were found to remove the phase transition observed in pure ceria below 973 K but appeared to have minimal effect on the oxidation enthalpies. Implications of these results for catalytic applications of ceria are discussed

    Oxidation entropies and enthalpies of ceria–zirconia solid solutions

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    The thermodynamic redox properties for a series of ceria–zirconia solid solutions have been measured by determining their oxidation isotherms between 873 and 1073 K. Isotherms were obtained using Coulometric titration and using O2 titration of samples equilibrated in flowing mixtures of H2 and H2O. Samples having the following compositions were studied after calcinations at 973 and 1323 K: CeO2, Ce0.92Zr0.08O2, Ce0.81Zr0.19O2, Ce0.59Zr0.41O2, Ce0.50Zr0.50O2, Ce0.25Zr0.75O2, Ce0.14Zr0.86O2, and ZrO2. While the oxidation enthalpy for CeO2 was between −750 and −800 kJ/mol O2, the oxidation enthalpies for each of the solid solutions were between −500 and −550 kJ/mol O2 and essentially independent of the extent of reduction. The shapes of the isotherms for the solid solutions were affected by the oxidation entropies, which depended strongly on the sample composition and the extent of reduction. With CeO2, Ce0.92Zr0.08O2, and Ce0.14Zr0.86O2, the samples remained single-phase after calcination at 1323 K and the thermodynamic redox properties were unaffected. By contrast, Ce0.59Zr0.41O2 formed two phases following calcination at 1323 K, Ce0.78Zr0.22O2 (71 wt.%) and Ce0.13Zr0.87O2 (29 wt.%); the isotherm changed to that which would be expected for a physical mixture of the two phases. A model is presented which views reduction of the solid solutions in terms of the local atomic structure, with the formation of pyrochlore-like clusters causing the increased reducibility of the solid solutions. Some of the changes in reducibility are associated with the number of sites from which oxygen can be removed in order to form pyrochlore-like clusters

    The long noncoding RNA neuroLNC regulates presynaptic activity by interacting with the neurodegeneration-associated protein TDP-43

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    The cellular and the molecular mechanisms by which long noncoding RNAs (lncRNAs) may regulate presynaptic function and neuronal activity are largely unexplored. Here, we established an integrated screening strategy to discover lncRNAs implicated in neurotransmitter and synaptic vesicle release. With this approach, we identified neuroLNC, a neuron-specific nuclear lncRNA conserved from rodents to humans. NeuroLNC is tuned by synaptic activity and influences several other essential aspects of neuronal development including calcium influx, neuritogenesis, and neuronal migration in vivo. We defined the molecular interactors of neuroLNC in detail using chromatin isolation by RNA purification, RNA interactome analysis, and protein mass spectrometry. We found that the effects of neuroLNC on synaptic vesicle release require interaction with the RNA-binding protein TDP-43 (TAR DNA binding protein-43) and the selective stabilization of mRNAs encoding for presynaptic proteins. These results provide the first proof of an lncRNA that orchestrates neuronal excitability by influencing presynaptic function

    From programme theory to logic models for multispecialty community providers: a realist evidence synthesis

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    This is the final version. Available from the publisher via the DOI in this record.Background: The NHS policy of constructing multispecialty community providers (MCPs) rests on a complex set of assumptions about how health systems can replace hospital use with enhanced primary care for people with complex, chronic or multiple health problems, while contributing savings to health-care budgets. Objectives: To use policy-makers’ assumptions to elicit an initial programme theory (IPT) of how MCPs can achieve their outcomes and to compare this with published secondary evidence and revise the programme theory accordingly. Design: Realist synthesis with a three-stage method: (1) for policy documents, elicit the IPT underlying the MCP policy, (2) review and synthesise secondary evidence relevant to those assumptions and (3) compare the programme theory with the secondary evidence and, when necessary, reformulate the programme theory in a more evidence-based way. Data sources: Systematic searches and data extraction using (1) the Health Management Information Consortium (HMIC) database for policy statements and (2) topically appropriate databases, including MEDLINE, MEDLINE In-Process & Other Non-Indexed Citations, PsycINFO, the Cumulative Index to Nursing and Allied Health Literature (CINAHL) and Applied Social Sciences Index and Abstracts (ASSIA). A total of 1319 titles and abstracts were reviewed in two rounds and 116 were selected for full-text data extraction. We extracted data using a formal data extraction tool and synthesised them using a framework reflecting the main policy assumptions. Results: The IPT of MCPs contained 28 interconnected context–mechanism–outcome relationships. Few policy statements specified what contexts the policy mechanisms required. We found strong evidence supporting the IPT assumptions concerning organisational culture, interorganisational network management, multidisciplinary teams (MDTs), the uses and effects of health information technology (HIT) in MCP-like settings, planned referral networks, care planning for individual patients and the diversion of patients from inpatient to primary care. The evidence was weaker, or mixed (supporting some of the constituent assumptions but not others), concerning voluntary sector involvement, the effects of preventative care on hospital admissions and patient experience, planned referral networks and demand management systems. The evidence about the effects of referral reductions on costs was equivocal. We found no studies confirming that the development of preventative care would reduce demands on inpatient services. The IPT had overlooked certain mechanisms relevant to MCPs, mostly concerning MDTs and the uses of HITs. Limitations: The studies reviewed were limited to Organisation for Economic Co-operation and Development countries and, because of the large amount of published material, the period 2014–16, assuming that later studies, especially systematic reviews, already include important earlier findings. No empirical studies of MCPs yet existed. Conclusions: Multidisciplinary teams are a central mechanism by which MCPs (and equivalent networks and organisations) work, provided that the teams include the relevant professions (hence, organisations) and, for care planning, individual patients. Further primary research would be required to test elements of the revised logic model, in particular about (1) how MDTs and enhanced general practice compare and interact, or can be combined, in managing referral networks and (2) under what circumstances diverting patients from in-patient to primary care reduces NHS costs and improves the quality of patient experience.National Institute for Health Research (NIHR

    Protein phosphorylation in depolarized synaptosomes: Dissecting primary effects of calcium from synaptic vesicle cycling

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    Synaptic transmission is mediated by the regulated exocytosis of synaptic vesicles. When the presynaptic membrane is depolarized by an incoming action potential, voltage-gated calcium channels open, resulting in the influx of calcium ions that triggers the fusion of synaptic vesicles (SVs) with the plasma membrane. SVs are recycled by endocytosis. Phosphorylation of synaptic proteins plays a major role in these processes, and several studies have shown that the synaptic phosphoproteome changes rapidly in response to depolarization. However, it is unclear which of these changes are directly linked to SV cycling and which might regulate other presynaptic functions that are also controlled by calcium-dependent kinases and phosphatases. To address this question, we analyzed changes in the phosphoproteome using rat synaptosomes in which exocytosis was blocked with botulinum neurotoxins (BoNTs) while depolarization-induced calcium influx remained unchanged. BoNT-treatment significantly alters the response of the synaptic phoshoproteome to depolarization and results in reduced phosphorylation levels when compared with stimulation of synaptosomes by depolarization with KCl alone. We dissect the primary Ca2+-dependent phosphorylation from SV-cycling-dependent phosphorylation and confirm an effect of such SV-cycling-dependent phosphorylation events on syntaxin-1a-T21/T23, synaptobrevin-S75, and cannabinoid receptor-1-S314/T322 on exo- and endocytosis in cultured hippocampal neurons

    From Programme Theory to Logic Models for Multispecialty Community Providers: A Realist Evidence Synthesis

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    Background: The NHS policy of constructing multispecialty community providers (MCPs) rests on a complex set of assumptions about how health systems can replace hospital use with enhanced primary care for people with complex, chronic or multiple health problems, while contributing savings to health-care budgets. Objectives: To use policy-makers’ assumptions to elicit an initial programme theory (IPT) of how MCPs can achieve their outcomes and to compare this with published secondary evidence and revise the programme theory accordingly. Design: Realist synthesis with a three-stage method: (1) for policy documents, elicit the IPT underlying the MCP policy, (2) review and synthesise secondary evidence relevant to those assumptions and (3) compare the programme theory with the secondary evidence and, when necessary, reformulate the programme theory in a more evidence-based way. Data sources: Systematic searches and data extraction using (1) the Health Management Information Consortium (HMIC) database for policy statements and (2) topically appropriate databases, including MEDLINE, MEDLINE In-Process & Other Non-Indexed Citations, PsycINFO, the Cumulative Index to Nursing and Allied Health Literature (CINAHL) and Applied Social Sciences Index and Abstracts (ASSIA). A total of 1319 titles and abstracts were reviewed in two rounds and 116 were selected for full-text data extraction. We extracted data using a formal data extraction tool and synthesised them using a framework reflecting the main policy assumptions. Results: The IPT of MCPs contained 28 interconnected context–mechanism–outcome relationships. Few policy statements specified what contexts the policy mechanisms required. We found strong evidence supporting the IPT assumptions concerning organisational culture, interorganisational network management, multidisciplinary teams (MDTs), the uses and effects of health information technology (HIT) in MCP-like settings, planned referral networks, care planning for individual patients and the diversion of patients from inpatient to primary care. The evidence was weaker, or mixed (supporting some of the constituent assumptions but not others), concerning voluntary sector involvement, the effects of preventative care on hospital admissions and patient experience, planned referral networks and demand management systems. The evidence about the effects of referral reductions on costs was equivocal. We found no studies confirming that the development of preventative care would reduce demands on inpatient services. The IPT had overlooked certain mechanisms relevant to MCPs, mostly concerning MDTs and the uses of HITs. Limitations: The studies reviewed were limited to Organisation for Economic Co-operation and Development countries and, because of the large amount of published material, the period 2014–16, assuming that later studies, especially systematic reviews, already include important earlier findings. No empirical studies of MCPs yet existed. Conclusions: Multidisciplinary teams are a central mechanism by which MCPs (and equivalent networks and organisations) work, provided that the teams include the relevant professions (hence, organisations) and, for care planning, individual patients. Further primary research would be required to test elements of the revised logic model, in particular about (1) how MDTs and enhanced general practice compare and interact, or can be combined, in managing referral networks and (2) under what circumstances diverting patients from in-patient to primary care reduces NHS costs and improves the quality of patient experience

    Monitoring mitochondrial translation in living cells

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    Mitochondria possess a small genome that codes for core subunits of the oxidative phosphorylation system and whose expression is essential for energy production. Information on the regulation and spatial organization of mitochondrial gene expression in the cellular context has been difficult to obtain. Here we devise an imaging approach to analyze mitochondrial translation within the context of single cells, by following the incorporation of clickable non-canonical amino acids. We apply this method to multiple cell types, including specialized cells such as cardiomyocytes and neurons, and monitor with spatial resolution mitochondrial translation in axons and dendrites. We also show that translation imaging allows to monitor mitochondrial protein expression in patient fibroblasts. Approaching mitochondrial translation with click chemistry opens new avenues to understand how mitochondrial biogenesis is integrated into the cellular context and can be used to assess mitochondrial gene expression in mitochondrial diseases

    Autoimmune encephalitis and CSF anti-glur3 antibodies in an MS patient after alemtuzumab treatment

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    A 45-year-old Italian woman, affected by relapsing-remitting multiple sclerosis (RR-MS) starting from 2011, started treatment with alemtuzumab in July 2016. Nine months after the second infusion, she had an immune thrombocytopenic purpura (ITP) with complete recovery after steroid treatment. Three months after the ITP, the patient presented with transient aphasia, cognitive deficits, and focal epilepsy. Serial brain magnetic resonance imaging showed a pattern compatible with encephalitis. Autoantibodies to glutamate receptor 3 peptide A and B were detected in cerebrospinal fluid and serum, in the absence of any other diagnostic cues. After three courses of intravenous immunoglobulin (0.4 mg/kg/day for 5 days, 1 month apart), followed by boosters (0.4 mg/kg/day) every 4-6 weeks, her neurological status improved and is currently comparable with that preceding the encephalitis. Autoimmune complications of the central nervous system during alemtuzumab therapy are relatively rare: only one previous case of autoimmune encephalitis following alemtuzumab treatment has been reported to date

    Investigating Supply Chains Models and Enabling Technologies Towards Collaborative Networks

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    This research employs an extensive multiple case studies analysis to identify the most important business models affecting supply chain configurations and related enabling technologies towards the creation of collaborative networks. The results obtained from the investigation of 24 companies of manufacturing and process industry, informed by literature, identify four ‘design principles’ of business models, i.e. Personalized production, Servitization, Decentralized and modular production, and Recycle, Re-use and Sustainability. Each model is further described and discussed at the interplay between digitalization and collaborative network practices at supply chain level, showing that adopting one or a combination of the four design principles allows to actuate some of the most important features of collaboration like Vertical integration or networking of smart production systems, Horizontal integration through global value chain networks, Through-engineering across the entire value chain, Acceleration of manufacturing and Digitalization of products and services
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