402 research outputs found

    A Method to Improve the Neutrino Energy Reconstruction in LArTPCs

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    Precision measurements of the neutrino oscillation parameters allow to determine the potential violation of CP-symmetry in the leptonic sector. If the violation of CP-symmetry in the leptonic sector can be experimentally confirmed, this could become the preferred explanation in the Standard Model for the matter-antimatter asymmetry of the universe. The Deep Underground Neutrino Experiment (DUNE), which is being built by the Fermi National Accelerator Laboratory (FNAL) in the USA, aims to perform these measurements of the neutrino oscillation parameters using Liquid Argon Time Projection Chamber (LArTPC) detectors. Four massive multi-kt Far Detectors (FDs) are deployed together with a Near Detector (ND) that uses the same detector technology as the FDs. As a consequence of the high-intensity neutrino beam and the short distance to the neutrino source the ND will need the ability to disentangle multiple overlapping events that happen within a single readout cycle. This is achieved with a LArTPC following the ArgonCube concept, which was developed at the University of Bern. The ArgonCube concept divides the detector volume into a number of identical, optically isolated and electrically isolated Time Projection Chamber (TPC) modules. The optical isolation reduces the pile-up of the scintillation light and allows for better localization of light signals. The ND will need to measure the neutrino energy because neutrino oscillations occur as a function of the neutrino energy. Neutrons emerging from the neutrino interaction vertex can carry away more than 25 % of the neutrino energy, which is missed by applying the calorimetric method, because neutral particles are not reconstructed in LArTPCs. I have determined the bias and the uncertainty of the reconstructed neutrino energy due missed primary neutrons, based on simulations using the GENIE event generator. At the DUNE beam spectrum, primary neutrons will be involved in about 80 % of the neutrino-argon interactions. In those events with primary neutrons involved, a mean energy corresponding to ∼10 % of the parent neutrino’s kinetic energy is carried away by primary neutrons, and the relative uncertainty on the reconstructed neutrino energy can exceed 13 %. I have developed a method to identify neutrons in LArTPCs by secondary charged particles that are produced if a neutron interacts with an argon nucleus. These neutrons appear as detached energy deposits, which prevents a trivial assignment to the correct interaction vertex, given the high event multiplicity at the ND site. Therefore, I further developed a method to assign detached energy deposits to neutrino interaction verices, exploiting the fast response of the light-readout systems. With a timing resolution at the O (1) ns, the light-readout systems easily allow to separate the light signals of individual events, which have a mean separation time of 179 ns. If the presented methods are used to veto neutrino interactions with primary neutrons, then the respective uncertainty on the reconstructed neutrino energy can be reduced to < 10 %

    First Operation of a Resistive Shell Liquid Argon Time Projection Chamber -- A new Approach to Electric-Field Shaping

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    We present a new technology for the shaping of the electric field in Time Projection Chambers (TPCs) using a carbon-loaded polyimide foil. This technology allows for the minimisation of passive material near the active volume of the TPC and thus is capable to reduce background events originating from radioactive decays or scattering on the material itself. Furthermore, the high and continuous electric resistivity of the foil limits the power dissipation per unit area and minimizes the risks of damages in the case of an electric field breakdown. Replacing the conventional field cage with a resistive plastic film structure called 'shell' decreases the number of components within the TPC and therefore reduces the potential points of failure when operating the detector. A prototype liquid argon (LAr) TPC with such a resistive shell and with a cathode made of the same material was successfully tested for long term operation with electric field values up to about 1.5 kV/cm. The experiment shows that it is feasible to successfully produce and shape the electric field in liquefied noble-gas detectors with this new technology.Comment: 13 page

    Comparative Life Cycle Assessment Of Conventionally Manufactured And Additive Remanufactured Electric Bicycle Motors

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    In a circular economy, remanufacturing is crucial in reducing the use of primary raw materials and energy compared to new production. However, poor availability of non-standardized wear components can prevent remanufacturing. Additive manufacturing is a promising alternative to conventional manufacturing or spare part purchase for those wear components required for remanufacturing. However, there is uncertainty regarding the environmental impact of using additive manufacturing for remanufacturing. This paper compares conventional and additive spare parts manufacturing to evaluate the potential environmental savings of remanufacturing electric bicycle motors. Therefore, a reference motor was selected, and its manufacturing processes were modeled in SimaPro using the ecoinvent 3.8 Life Cycle Assessment database and the latest knowledge on processing and manufacturing processes. The results show that conventional production of electric bicycle motors has a climate warming potential of around 28 kg CO2-eq. Additive remanufacturing of electric bicycle motors at the end of their life cycle offers significant environmental savings potential. The extent of savings depends on the condition of the used electric bicycle motor and, accordingly, the number of components that need to be replaced. According to the IPCC method for the electric bicycle motor investigated, the study estimates that approximately 90.4 % savings potential can be achieved in terms of Global Warming Potential

    Paradoxical response of plasma atrial natriuretic hormone to pericardiocentesis in cardiac tamponade

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26804/1/0000360.pd

    Meditation and Cardiovascular Health: What is the Link?

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    Meditation as a form of body–mind interaction for primary and secondary prevention in cardiovascular disease has been discussed critically in the past. However, data that aimed to link this intervention to a reduction of various aspects of cardiovascular disease, rendering it a potential part of a cost-effective treatment approach in patients at risk, remain scarce and inconclusive. This article aims to provide an overview of currently available evidence in the literature and the potential impact of meditation on cardiovascular health. However, the data highlighted in this article cannot render with certainty directly reproducible effects of meditation on patients’ cardiovascular disease profiles. Meditation may be suggested only as an additional link in the chain of primary and secondary prevention until future research provides sufficient data on this topic

    Plasma levels of immunoreactive atrial natriuretic factor increase during supraventricular tachycardia

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    A significant diuretic and natriuretic response occurs during paroxysmal supraventricular tachycardia (SVT). Although the diuresis may be secondary to suppression of vasopressin secretion, the etiology of the natriuresis remains unexplained. To determine if atrial natriuretic factor (ANF) could contribute to the polyuric response during SVT, 10 patients were studied: five during spontaneous SVT and five during simulated SVT produced by rapid simultaneous atrial and ventricular pacing. Plasma immunoreactive ANF (IR-ANF) levels measured by radioimmunoassay were obtained at baseline (before and/or 24 to 48 hours after SVT) and after at least 15 minutes of SVT in all patients. During spontaneous and simulated SVT, IR-ANF was significantly elevated (mean +/- SE; 275 +/- 68 pmol/L) compared to baseline (28 +/- 7 pmol/L; P = 0.0036). Similar increases in IR-ANF were noted during both simulated and spontaneous SVT. To determine if this IR-ANF release was related to the increase in heart rate or the rise in right atrial pressure during SVT, IR-ANF levels were also measured in five patients with sinus tachycardia and in six patients with congestive heart failure, IR-ANF was significantly related to right atrial pressure (r = 0.93; P = 0.0009) but not to heart rate (r = 0.46). Thus, IR-ANF is elevated during SVT and may contribute to the natriuretic response. The stimulus to IR-ANF secretion during SVT appears to be related to the rise in right atrial pressure rather than to the increase in heart rate.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26001/1/0000067.pd
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