46 research outputs found

    Characterization of the liquid argon veto of the GERDA experiment and its application for the measurement of the 76Ge half-life

    Get PDF
    The search for neutrinoless double-beta decay (0νββ) is one of the most active fields in modern particle physics as the observation of this process would prove lepton number violation and imply new physics beyond the Standard Model of particle physics. The GERDA experiment searches for this decay by operating bare Germanium detectors, enriched in the ββ isotope 76 Ge, in liquid argon. For the first time, a ββ-experiment combines the excellent properties of semiconductor Germanium detectors with an active background suppression technique based on the simultaneous detection of liquid argon scintillation light by photomultiplier tubes and silicon photomultipliers coupled to scintillating fibers (LAr veto). The LAr veto has been successfully operated during the first six months of Phase II of the experiment and yielded – in combination with a Germanium detector pulse shape discrimination technique – a background index of \unit[(0.7^{+1.1}_{-0.5}) \cdot 10^{-3}]{(\frac{cts}{kg\cdot keV\cdot yr})}¹. With an ultimate exposure of 100 kg•yr this will allow for a 0νββ-decay half-life sensitivity of the Gerda Phase II experiment of 10^26 yr.Double-beta decay under the emission of two neutrinos (2νββ) is a second-order process but which is allowed by the Standard Model. The excellent background reduc- tion of the LAr veto results in an unprecedented signal-to-background ratio of 30:1 in the energy region dominated by 2νββ-decay of 76 Ge. The remaining background after LAr veto is estimated using the suppression factor from calibration source measurements and results in a measurement of ^{2\nu}_{1/2} = \unit[(1.98 \pm 0.02\textrm{ (stat)} \pm 0.05\textrm{ (syst)})\cdot 10^{21}]{yr} and T_{1/2}^{2\nu} =\unit[(1.92 \pm 0.02\textrm{ (stat)} \pm 0.11\textrm{ (syst)})\cdot 10^{21}]{yr}¹ based on two different detector designs and given uncertainties on the detector parameters but both with improved systematic uncertainties in comparison to earlier measurements. ¹) Please see rendered formula in original abstract as is prepended by the author to the attached full-text document

    Virtual reality-assisted cognitive behavioral therapy for patients with alcohol use disorder: a randomized feasibility study

    Get PDF
    IntroductionCognitive behavioral therapy (CBT) is an evidence-based treatment for alcohol use disorder (AUD). Exposure to high-risk situations in virtual reality (VR) has been suggested to have a potential therapeutical benefit, but no previous study has combined VR and CBT for AUD. We aimed to investigate the feasibility of using VR-simulated high-risk environments in CBT-based treatment of AUD.MethodsWe randomized ten treatment-seeking AUD-diagnosed individuals to three sessions of conventional CBT or VR-assisted CBT performed at two outpatient clinics in Denmark. In each session, patients randomized to VR-CBT were exposed to VR-simulations from a restaurant to induce authentic thoughts, emotions, physiological reactions, and craving for CBT purposes. The primary outcome measure was feasibility: Drop-out rate, psychological reactions, and simulator sickness. Secondary outcomes were assessment of preliminary short-term changes in alcohol consumption and craving from baseline to one-week and one-month follow-up. In addition, the study was conducted for training in operationalization of VR equipment, treatment manuals, and research questionnaires.ResultsThe majority of patients completed all study visits (90%). VR induced authentic high-risk related thoughts, emotions, and physiological reactions that were considered relevant for CBT by patients and therapists. Four of five patients randomized to VR-CBT experienced cravings during VR simulations, and most of these patients (3/5) experienced mild simulator sickness during VR exposure. The preliminary data showed that patients receiving VR-CBT had more reduction in alcohol consumption than patients receiving conventional CBT at one week- (median 94% vs. 72%) and one-month follow-up (median 98% vs. 55%). Similar results were found regarding changes in cravings.ConclusionWe demonstrated VR-CBT to be a feasible intervention for patients with AUD which supports continued investigations in a larger randomized clinical trial evaluating the efficacy of VR-CBT.Clinical trial registrationhttps://www.clinicaltrials.gov/study/NCT04990765?cond=addiction%20CRAVR&rank=2, identifier NCT05042180

    Laboratory for Essential Biodiversity Variables (EBV) Concepts – The “Data Pool Initiative for the Bohemian Forest Ecosystem”

    Get PDF
    Forest ecosystems respond very sensitively to climate and atmospheric changes. Feedback mechanisms can be measured via changes in albedo, energy balance and carbon storage. The Bavarian Forest National Park is a unique forest ecosystem with large non-intervention zones, which promote a large scale re-wilding process with low human interference. It provides important ecosystem services of clear water, carbon sequestration and recreation, and has fragile habitats with endangered forest species. The national park is therefore a very suitable field of research to study natural and near natural ecosystem processes. Under the leadership of the national park authority, experts from various European research institutions have joined forces to systematically establish a remote sensing data pool on the Bavarian Forest as a resource for their research. This collaborative effort provides an opportunity to combine various methodological approaches and data and to optimize products by sharing knowledge and expertise. The first objective of the data pool is to develop methods for the establishment of Essential Biodiversity Variables (EBV) based on a very sound and comprehensive data base. The recent advances in tighter collaboration of remote sensing and biodiversity science, especially with regard to the newly established EBV and RS-EBV concepts will help to improve the interdisciplinary research. However, such concepts and especially the underlying remote sensing data need to be developed, adapted and validated against biodiversity patterns. Such process needs an extensive set of in-situ and remotely sensed data in order to allow a thorough analysis. The Bavarian data pool fits these requirements through the commitment of all members and hence provides a variety of remote sensing data sets such as hyperspectral, Lidar as well as CIR and multispectral data, as well as a wealth of in-situ data of zoological and botanical transects. This combination allows setting sensor-specific, as well as species-specific analysis on different aspects, i.e. different processes between managed and natural forest, impact of climate change or species distribution mapping. The second objective is to develop concepts for EBV using Sentinel mission data combined with data from future contributing hyperspectral missions such as EnMAP. Spaceborne hyperspectral data has been identified by the remote sensing related biodiversity community as an important data source. However, the acquisition of airborne data is very expensive for regular coverage of forest stands and the entire forest ecosystem. This drawback will be overcome by the launch of the space-borne imaging spectroscopy mission EnMAP. It is a contributing mission to the Copernicus program and will be launched in 2018. EnMAP is expected to provide high quality imaging spectroscopy data on an operational basis and will be suitable for the retrieval of high resolution plant traits at local scales. First studies within the data pool have been focused on e.g. derivation of plant traits like chlorophyll, LAI and nitrogen and tree species classification with a special focus on rare species within the national park, just to name a few. Objective, purpose and content of the data pool will be shown as well as first selective developments

    Virtual reality-assisted cognitive behavioural therapy for outpatients with alcohol use disorder (CRAVR):A protocol for a randomised controlled trial

    Get PDF
    Introduction Alcohol use disorder (AUD) is a brain disorder linked to over 200 health conditions. Cognitive behavioural therapy (CBT) is considered the best practice in the treatment of AUD, but more than 60% of patients relapse within the first year after treatment. Psychotherapy combined with virtual reality (VR) has received increasing interest in the treatment of AUD. However, existing studies have primarily investigated the use of VR for cue reactivity. We therefore aimed to investigate the effect of VR-assisted CBT (VR-CBT). Methods and analysis This study is an assessor-blinded, randomised clinical trial being conducted at three outpatient clinics in Denmark. We will randomise 102 patients to 14 individual sessions of either manualised VR-CBT or CBT. The VR-CBT group will receive exposure to immersive high-risk VR situations from a pub, bar/party, restaurant, supermarket and at-home (30 videos) to activate high-risk-related beliefs and cravings for subsequent modification using CBT techniques. The treatment period is 6 months, and follow-up visits will be performed 3, 6, 9 and 12 months after inclusion. The primary outcome measure is the change in total alcohol consumption from baseline to 6 months after inclusion, measured with the Timeline Followback Method. Key secondary outcome measures include changes in the number of heavy drinking days, alcohol cravings, cognition, and symptoms of depression and anxiety. Ethics and dissemination Approval has been obtained by the research ethics committee in the Capital Region of Denmark (H-20082136) and the Danish Data Protection Agency (P-2021-217). All patients will receive both oral and written information about the trial and written informed consent will be obtained from each patient before inclusion. The study results will be disseminated in peer-reviewed publications and conference presentations. Trial registration number ClinicalTrial.gov, NCT05042180.</p

    Fuzzy species limits in Mediterranean gorgonians (Cnidaria, Octocorallia): inferences on speciation processes

    Get PDF
    The study of the interplay between speciation and hybridization is of primary importance in evolutionary biology. Octocorals are ecologically important species whose shallow phylogenetic relationships often remain to be studied. In the Mediterranean Sea, three congeneric octocorals can be observed in sympatry: Eunicella verrucosa, Eunicella cavolini and Eunicella singularis. They display morphological differences and E.singularis hosts photosynthetic Symbiodinium, contrary to the two other species. Two nuclear sequence markers were used to study speciation and gene flow between these species, through network analysis and Approximate Bayesian Computation (ABC). Shared sequences indicated the possibility of hybridization or incomplete lineage sorting. According to ABC, a scenario of gene flow through secondary contact was the best model to explain these results. At the intraspecific level, neither geographical nor ecological isolation corresponded to distinct genetic lineages in E.cavolini. These results are discussed in the light of the potential role of ecology and genetic incompatibilities in the persistence of species limits.French National Research Agency (ANR) program Adacni (ANR) [ANR-12-ADAP-0016]CNRSHubert Curien 'Tassili' program [12MDU853]CCMAR Strategic Plan from Fundacao para a Ciencia e a Tecnologia-FCT [PEst-C/MAR/LA0015/2011,FEDERinfo:eu-repo/semantics/publishedVersio

    Diagnostic value of left bundle branch block in patients with acute myocardial infarction. A prospective analysis

    No full text
    In contemporary practice with early catheterization in most patients with suspected acute myocardial infarction, the clinical utility of new or presumably new left bundle branch block (LBBB) as a diagnostic criterion equivalent to ST-segment elevation is not well established. This study therefore aimed to determine the predictive value of LBBB for the diagnosis of acute transmural myocardial infarction (or ST-segment elevation myocardial infarction, STEMI). Between November 2006 and December 2011, 1,139 consecutive patients presenting to the heart center of the University of Cologne with suspected STEMI were examined. Of these patients, 935 presented with ST elevation, 72 with LBBB, and 132 had neither of these ECG changes. The diagnosis was confirmed with immediate coronary angiography. Compared with ST-segment elevation, LBBB was associated with a higher prevalence of cardiovascular risk factors and end-organ damage, and more patients with LBBB presented with pulmonary edema or cardiogenic shock (Killip III/IV). STEMI was confirmed in 58.3 % of patients with LBBB and in 86.4 % with ST-segment elevation. The sensitivity (0.38 [0.29-0.46]; odds ratio: 1.24) and specificity (0.67 [0.58-0.77]) of LBBB for the prediction of STEMI were low. However, the additional assessment of troponin T (> 0.1 A mu g/l) increased the predictive value of LBBB significantly. After adjusting for age and gender, no difference in mortality was found between the groups. LBBB with acute chest pain characterizes a cohort of patients with high morbidity and mortality. For the triage of these patients at first contact, additional criteria should be evaluated, which could increase the specificity of LBBB for the diagnosis of STEMI

    Long-term medication adherence in patients with ST-elevation myocardial infarction and primary percutaneous coronary intervention

    No full text
    Aims Besides early percutaneous coronary intervention (PCI) long-term medical treatment is crucial for outcomes after ST-elevation myocardial infarction (STEMI). The present study aimed to identify predictors of adherence to evidence-based medication in this high risk population. Methods and results A total of 1025 consecutive patients with adjudicated STEMI treated by primary PCI in a single centre as part of the Cologne Infarction Model (KIM) were prospectively analysed. Gender-specific multivariate predictors of long-term medication adherence were identified. Follow-up with available information on drug use was completed for 610 of 738 (82.7%) patients confirmed to be alive after a median period of 36 months. Adherence was persistently high for evidence-based medication with 90.8% for acetylsalicylic acid (ASA), 88.2% for statins, 87.5% for beta-blockers and 79.2% for ACE-inhibitors or angiotensin-receptor blockers (ARBs). Patients with a history of heart failure had a higher medication adherence to beta-blockers, ACE-inhibitors/ARBs and diuretics, whereas long-term prescription rates for calcium channel blockers (CCBs) were lower in patients with reduced versus preserved ejection fraction. Patients with a history of hypertension presented higher medication adherence to CCBs, ACE-inhibitors/ARBs and diuretics but not to beta-blockers. On multivariate analysis, age, body mass index (BMI), hypertension, chronic kidney disease and lack of PCI were independently associated with prescription of diuretics at follow-up. In women, adherence was lower to beta-blockers and higher to CCBs compared to men. Conclusion In the high risk population of STEMI patients long-term adherence to evidence-based medication is high. The lower adherence to beta-blockers and higher prescription rate for CCBs in women needs particular attention

    Exploring Optimal Dark Current Design in HgCdTe Infrared Barrier Detectors: A TCAD and Semianalytic Investigation

    No full text
    The dark current is a fundamental figure of merit to characterize the performance of high-sensitivity, low-noise mid- and far-infrared barrier photodetectors. In the context of HgCdTe barrier photodetectors, the trend is to use very low doping concentrations, in an attempt to minimize recombination processes. In the present work, through TCAD simulations, we delve deeper into the design of low-dark-current pBnp{\mathrm{B}}n detectors, showing the possible existence of an optimum doping. This occurrence is investigated and interpreted also by means of closed-form expressions for the lifetimes, emphasizing the role of the interplay between Auger and Shockley-Read-Hall generation processes
    corecore