24 research outputs found

    Stable isotope compositions of the Penninic ophiolites of the KÔszeg-Rechnitz series

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    Abstract The ophiolitic rocks of the easternmost Penninic unit, the KƑszeg-Rechnitz series, were analyzed for their H, C and O stable isotope compositions. Serpentinite, gabbro, blueschist, talc deposits, ophicarbonates, as well as calcite and inclusion fluids from quartz segregation veins were analyzed in order to determine the effects of different metamorphic events on the stable isotope compositions. The oxygen isotope compositions have a wide range depending on rock type and locality. Gabbro and serpentinite of BienenhĂŒtte (Bernstein Window) have preserved mantle-like ÎŽ18O values (5.9 to 6.3‰; all values are in ‰ relative to V-SMOW), whereas the serpentinite of GlashĂŒtten and Rumpersdorf (KƑszeg-Rechnitz Window) and the silicate minerals of the ophicarbonate rocks show a strong 18O-enrichment (up to 16.2‰). The 18O-enrichment may have been induced by low-temperature serpentinization or interaction with 18O-rich fluids that had been in equilibrium with sedimentary rocks. Contrary to the O isotope compositions, the H isotope compositions seem to be homogeneous in the entire series, with D values of −63 ± 7‰. Only some serpentinite rocks were depleted in D (down to −106‰), usually regarded as a result of interaction with meteoric water infiltrating during late-stage metamorphism. The meteoric water infiltration was rather limited, as even samples taken directly from slickensides within serpentinite bodies preserved isotopic compositions close to those of the bulk series. H and O isotope compositions of fluids mobilized in the metasedimentary rocks of the Penninic unit during the main metamorphic stage were determined by analyzing inclusion fluids and calcites in quartz-carbonate veins. The isotope compositions indicate interaction between these fluids and the ophiolite series, although relative deuterium enrichment has been preserved in the ophiolitic rocks. The strong D-enrichment characteristic for oceanic crust that has experienced high-temperature interaction with seawater was not detected. However, the H isotope compositions obtained for the KƑszeg-Rechnitz series indicate that subduction of the Penninic oceanic crust and the associated devolatilization may have been potentially responsible for mantle metasomatism, resulting in H isotope compositions of about −40‰, similar to the range determined from mantle-derived amphibole megacrysts (DemĂ©ny et al. 2005). To conclude, the present dataset is discussed in the light of earlier studies on the formation of the Sopron leucophyllite

    Learning Throttle Valve Control Using Policy Search

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    Abstract. The throttle valve is a technical device used for regulating a fluid or a gas flow. Throttle valve control is a challenging task, due to its complex dynamics and demanding constraints for the controller. Using state-of-the-art throttle valve control, such as model-free PID controllers, time-consuming and manual adjusting of the controller is necessary. In this paper, we investigate how reinforcement learning (RL) can help to alleviate the effort of manual controller design by automatically learning a control policy from experiences. In order to obtain a valid control policy for the throttle valve, several constraints need to be addressed, such as no-overshoot. Furthermore, the learned controller must be able to follow given desired trajectories, while moving the valve from any start to any goal position and, thus, multi-targets policy learning needs to be considered for RL. In this study, we employ a policy search RL approach, Pilco [2], to learn a throttle valve control policy. We adapt the Pilco algorithm, while taking into account the practical requirements and constraints for the controller. For evaluation, we employ the resulting algorithm to solve several control tasks in simulation, as well as on a physical throttle valve system. The results show that policy search RL is able to learn a consistent control policy for complex, real-world systems.

    Human Infections with Borna Disease Virus 1 (BoDV-1) Primarily Lead to Severe Encephalitis: Further Evidence from the Seroepidemiological BoSOT Study in an Endemic Region in Southern Germany

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    More than 40 human cases of severe encephalitis caused by Borna disease virus 1 (BoDV-1) have been reported to German health authorities. In an endemic region in southern Germany, we conducted the seroepidemiological BoSOT study (“BoDV-1 after solid-organ transplantation”) to assess whether there are undetected oligo- or asymptomatic courses of infection. A total of 216 healthy blood donors and 280 outpatients after solid organ transplantation were screened by a recombinant BoDV-1 ELISA followed by an indirect immunofluorescence assay (iIFA) as confirmatory test. For comparison, 288 serum and 258 cerebrospinal fluid (CSF) samples with a request for tick-borne encephalitis (TBE) diagnostics were analyzed for BoDV-1 infections. ELISA screening reactivity rates ranged from 3.5% to 18.6% depending on the cohort and the used ELISA antigen, but only one sample of a patient from the cohort with requested TBE diagnostics was confirmed to be positive for anti-BoDV-1-IgG by iIFA. In addition, the corresponding CSF sample of this patient with a three-week history of severe neurological disease tested positive for BoDV-1 RNA. Due to the iIFA results, all other results were interpreted as false-reactive in the ELISA screening. By linear serological epitope mapping, cross-reactions with human and bacterial proteins were identified as possible underlying mechanism for the false-reactive ELISA screening results. In conclusion, no oligo- or asymptomatic infections were detected in the studied cohorts. Serological tests based on a single recombinant BoDV-1 antigen should be interpreted with caution, and an iIFA should always be performed in addition

    Peri-operative red blood cell transfusion in neonates and infants: NEonate and Children audiT of Anaesthesia pRactice IN Europe: A prospective European multicentre observational study

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    BACKGROUND: Little is known about current clinical practice concerning peri-operative red blood cell transfusion in neonates and small infants. Guidelines suggest transfusions based on haemoglobin thresholds ranging from 8.5 to 12 g dl-1, distinguishing between children from birth to day 7 (week 1), from day 8 to day 14 (week 2) or from day 15 (≄week 3) onwards. OBJECTIVE: To observe peri-operative red blood cell transfusion practice according to guidelines in relation to patient outcome. DESIGN: A multicentre observational study. SETTING: The NEonate-Children sTudy of Anaesthesia pRactice IN Europe (NECTARINE) trial recruited patients up to 60 weeks' postmenstrual age undergoing anaesthesia for surgical or diagnostic procedures from 165 centres in 31 European countries between March 2016 and January 2017. PATIENTS: The data included 5609 patients undergoing 6542 procedures. Inclusion criteria was a peri-operative red blood cell transfusion. MAIN OUTCOME MEASURES: The primary endpoint was the haemoglobin level triggering a transfusion for neonates in week 1, week 2 and week 3. Secondary endpoints were transfusion volumes, 'delta haemoglobin' (preprocedure - transfusion-triggering) and 30-day and 90-day morbidity and mortality. RESULTS: Peri-operative red blood cell transfusions were recorded during 447 procedures (6.9%). The median haemoglobin levels triggering a transfusion were 9.6 [IQR 8.7 to 10.9] g dl-1 for neonates in week 1, 9.6 [7.7 to 10.4] g dl-1 in week 2 and 8.0 [7.3 to 9.0] g dl-1 in week 3. The median transfusion volume was 17.1 [11.1 to 26.4] ml kg-1 with a median delta haemoglobin of 1.8 [0.0 to 3.6] g dl-1. Thirty-day morbidity was 47.8% with an overall mortality of 11.3%. CONCLUSIONS: Results indicate lower transfusion-triggering haemoglobin thresholds in clinical practice than suggested by current guidelines. The high morbidity and mortality of this NECTARINE sub-cohort calls for investigative action and evidence-based guidelines addressing peri-operative red blood cell transfusions strategies. TRIAL REGISTRATION: ClinicalTrials.gov, identifier: NCT02350348
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