45 research outputs found

    Operation and performance of the ATLAS semiconductor tracker

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    The semiconductor tracker is a silicon microstrip detector forming part of the inner tracking system of the ATLAS experiment at the LHC. The operation and performance of the semiconductor tracker during the first years of LHC running are described. More than 99% of the detector modules were operational during this period, with an average intrinsic hit efficiency of (99.74±0.04)%. The evolution of the noise occupancy is discussed, and measurements of the Lorentz angle, Ύ-ray production and energy loss presented. The alignment of the detector is found to be stable at the few-micron level over long periods of time. Radiation damage measurements, which include the evolution of detector leakage currents, are found to be consistent with predictions and are used in the verification of radiation background simulations

    Zika virus infection in pregnancy: a protocol for the joint analysis of the prospective cohort studies of the ZIKAlliance, ZikaPLAN and ZIKAction consortia

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    INTRODUCTION: Zika virus (ZIKV) infection in pregnancy has been associated with microcephaly and severe neurological damage to the fetus. Our aim is to document the risks of adverse pregnancy and birth outcomes and the prevalence of laboratory markers of congenital infection in deliveries to women experiencing ZIKV infection during pregnancy, using data from European Commission-funded prospective cohort studies in 20 centres in 11 countries across Latin America and the Caribbean. METHODS AND ANALYSIS: We will carry out a centre-by-centre analysis of the risks of adverse pregnancy and birth outcomes, comparing women with confirmed and suspected ZIKV infection in pregnancy to those with no evidence of infection in pregnancy. We will document the proportion of deliveries in which laboratory markers of congenital infection were present. Finally, we will investigate the associations of trimester of maternal infection in pregnancy, presence or absence of maternal symptoms of acute ZIKV infection and previous flavivirus infections with adverse outcomes and with markers of congenital infection. Centre-specific estimates will be pooled using a two-stage approach. ETHICS AND DISSEMINATION: Ethical approval was obtained at each centre. Findings will be presented at international conferences and published in peer-reviewed open access journals and discussed with local public health officials and representatives of the national Ministries of Health, Pan American Health Organization and WHO involved with ZIKV prevention and control activities

    25th annual computational neuroscience meeting: CNS-2016

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    The same neuron may play different functional roles in the neural circuits to which it belongs. For example, neurons in the Tritonia pedal ganglia may participate in variable phases of the swim motor rhythms [1]. While such neuronal functional variability is likely to play a major role the delivery of the functionality of neural systems, it is difficult to study it in most nervous systems. We work on the pyloric rhythm network of the crustacean stomatogastric ganglion (STG) [2]. Typically network models of the STG treat neurons of the same functional type as a single model neuron (e.g. PD neurons), assuming the same conductance parameters for these neurons and implying their synchronous firing [3, 4]. However, simultaneous recording of PD neurons shows differences between the timings of spikes of these neurons. This may indicate functional variability of these neurons. Here we modelled separately the two PD neurons of the STG in a multi-neuron model of the pyloric network. Our neuron models comply with known correlations between conductance parameters of ionic currents. Our results reproduce the experimental finding of increasing spike time distance between spikes originating from the two model PD neurons during their synchronised burst phase. The PD neuron with the larger calcium conductance generates its spikes before the other PD neuron. Larger potassium conductance values in the follower neuron imply longer delays between spikes, see Fig. 17.Neuromodulators change the conductance parameters of neurons and maintain the ratios of these parameters [5]. Our results show that such changes may shift the individual contribution of two PD neurons to the PD-phase of the pyloric rhythm altering their functionality within this rhythm. Our work paves the way towards an accessible experimental and computational framework for the analysis of the mechanisms and impact of functional variability of neurons within the neural circuits to which they belong

    Prenatal alcohol consumption and placental outcomes: a systematic review and meta-analysis of clinical studies

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    December 2021Objective: A systematic review was conducted to determine placental outcomes following prenatal alcohol exposure in women. Data Sources: The search terms “maternal OR prenatal OR pregnant OR periconception” AND “placenta” AND “alcohol OR ethanol” were used across 5 databases (PubMed, Embase, Cochrane Library, Web of Science, and CINAHL) from inception until November 2020. Study Eligibility Criteria: Articles were included if they reported placental outcomes in an alcohol exposure group compared with a control group. Studies were excluded if placentas were from elective termination before 20 weeks’ gestation, animal studies, in vitro studies, case studies, or coexposure studies. Methods: Study quality was assessed by 2 reviewers using the Newcastle-Ottawa Quality Assessment Scale. Title and abstract screening was conducted by 2 reviewers to remove duplicates and irrelevant studies. Remaining full text articles were screened by 2 reviewers against inclusion and exclusion criteria. Placental outcome data were extracted and tabulated separately for studies of placentation, placental weight, placental morphology, and placental molecular studies. Meta-analyses were conducted for outcomes reported by >3 studies. Results: Database searching retrieved 640 unique records. Screening against inclusion and exclusion criteria resulted in 33 included studies. The quality assessment identified that 61% of studies were high quality, 30% were average quality, and 9% were low quality. Meta-analyses indicated that prenatal alcohol exposure increased the likelihood of placental abruption (odds ratio, 1.48; 95% confidence interval, 1.37–1.60) but not placenta previa (odds ratio, 1.14; 95% confidence interval, 0.84–1.34) and resulted in a reduction in placental weight of 51 g (95% confidence interval, −82.8 to −19.3). Reports of altered placental vasculature, placental DNA methylation, and gene expression following prenatal alcohol exposure were identified. A single study examined placentas from male and female infants separately and found sex-specific placental outcomes. Conclusion: Prenatal alcohol exposure increases the likelihood of placental abruption and is associated with decreased placental weight, altered placental vasculature, DNA methylation, and molecular pathways. Given the critical role of the placenta in determining pregnancy outcomes, further studies investigating the molecular mechanisms underlying alcohol-induced placental dysfunction are required. Sex-specific placental adaptations to adverse conditions in utero have been well documented; thus, future studies should examine prenatal alcohol exposure–associated placental outcomes separately by sex.Sarah E. Steane, Sophia L. Young, Vicki L. Clifton, Linda A. Gallo, Lisa K. Akison, Karen M. Morit
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