4,299 research outputs found

    EUSO-SPB1 mission and science

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    International audienceThe Extreme Universe Space Observatory on a Super Pressure Balloon 1 (EUSO-SPB1) was launched in 2017 April from Wanaka, New Zealand. The plan of this mission of opportunity on a NASA super pressure balloon test flight was to circle the southern hemisphere. The primary scientific goal was to make the first observations of ultra-high-energy cosmic-ray extensive air showers (EASs) by looking down on the atmosphere with an ultraviolet (UV) fluorescence telescope from suborbital altitude (33 km). After 12 days and 4 h aloft, the flight was terminated prematurely in the Pacific Ocean. Before the flight, the instrument was tested extensively in the West Desert of Utah, USA, with UV point sources and lasers. The test results indicated that the instrument had sensitivity to EASs of ⪆3 EeV. Simulations of the telescope system, telescope on time, and realized flight trajectory predicted an observation of about 1 event assuming clear sky conditions. The effects of high clouds were estimated to reduce this value by approximately a factor of 2. A manual search and a machine-learning-based search did not find any EAS signals in these data. Here we review the EUSO-SPB1 instrument and flight and the EAS search

    EUSO-Offline: A comprehensive simulation and analysis framework

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    International audienceThe complexity of modern cosmic ray observatories and therich data sets they capture often require a sophisticated softwareframework to support the simulation of physical processes, detectorresponse, as well as reconstruction and analysis of real andsimulated data. Here we present the EUSO-Offline framework. Thecode base was originally developed by the Pierre AugerCollaboration, and portions of it have been adopted by othercollaborations to suit their needs. We have extended this softwareto fulfill the requirements of Ultra-High Energy Cosmic Raydetectors and very high energy neutrino detectors developed for theJoint Exploratory Missions for an Extreme Universe Observatory(JEM-EUSO). These path-finder instruments constitute a program tochart the path to a future space-based mission like POEMMA. Forcompleteness, we describe the overall structure of the frameworkdeveloped by the Auger collaboration and continue with a descriptionof the JEM-EUSO simulation and reconstruction capabilities. Theframework is written predominantly in modern C++ (compliled againstC++17) and incorporates third-party libraries chosen based onfunctionality and our best judgment regarding support andlongevity. Modularity is a central notion in the framework design, arequirement for large collaborations in which many individualscontribute to a common code base and often want to compare differentapproaches to a given problem. For the same reason, the framework isdesigned to be highly configurable, which allows us to contend witha variety of JEM-EUSO missions and observation scenarios. We alsodiscuss how we incorporate broad, industry-standard testing coveragewhich is necessary to ensure quality and maintainability of arelatively large code base, and the tools we employ to support amultitude of computing platforms and enable fast, reliableinstallation of external packages. Finally, we provide a fewexamples of simulation and reconstruction applications usingEUSO-Offline

    EUSO-Offline: A comprehensive simulation and analysis framework

    No full text
    International audienceThe complexity of modern cosmic ray observatories and therich data sets they capture often require a sophisticated softwareframework to support the simulation of physical processes, detectorresponse, as well as reconstruction and analysis of real andsimulated data. Here we present the EUSO-Offline framework. Thecode base was originally developed by the Pierre AugerCollaboration, and portions of it have been adopted by othercollaborations to suit their needs. We have extended this softwareto fulfill the requirements of Ultra-High Energy Cosmic Raydetectors and very high energy neutrino detectors developed for theJoint Exploratory Missions for an Extreme Universe Observatory(JEM-EUSO). These path-finder instruments constitute a program tochart the path to a future space-based mission like POEMMA. Forcompleteness, we describe the overall structure of the frameworkdeveloped by the Auger collaboration and continue with a descriptionof the JEM-EUSO simulation and reconstruction capabilities. Theframework is written predominantly in modern C++ (compliled againstC++17) and incorporates third-party libraries chosen based onfunctionality and our best judgment regarding support andlongevity. Modularity is a central notion in the framework design, arequirement for large collaborations in which many individualscontribute to a common code base and often want to compare differentapproaches to a given problem. For the same reason, the framework isdesigned to be highly configurable, which allows us to contend witha variety of JEM-EUSO missions and observation scenarios. We alsodiscuss how we incorporate broad, industry-standard testing coveragewhich is necessary to ensure quality and maintainability of arelatively large code base, and the tools we employ to support amultitude of computing platforms and enable fast, reliableinstallation of external packages. Finally, we provide a fewexamples of simulation and reconstruction applications usingEUSO-Offline

    Constraining models for the origin of ultra-high-energy cosmic rays with a novel combined analysis of arrival directions, spectrum, and composition data measured at the Pierre Auger Observatory

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    A review on life cycle environmental impacts of emerging solar cells

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    The development of solar technologies requires increased efficiency in converting solar radiation to energy, as well as innovative materials and structure to go beyond the conventional power conversion ratio. In line with these innovations, there are concerns about greenhouse gas emissions of the solar cells, materials for the solar technologies and other relevant environmental impacts of the manufacturing processes. This review is conducted on life cycle assessments of solar cells, considering the climate change and natural resource shortage context. It is identified that the majority of existing life cycle assessments on solar cells take into account four typical environmental impacts: energy consumption, greenhouse gas emissions, material depletion, and toxicity. Though the diverse methodological aspects make it difficult to directly compare these environmental impacts among various types of solar cells, the obtained results hinder that emerging solar cells such as perovskite solar cells or tandem solar cells are likely to have better environmental profiles than conventional silicon based and thin film solar cells, in terms of energy consumption, greenhouse gas emissions and material consumption. However, the emerging solar cells may utilize toxic materials in which their eco-toxicity and human toxicity should be further considered during the design of the technologies. Moreover, it is identified that the energy and environmental hotspot lies in the manufacturing process, regardless of impact indicators and types of solar cells

    Simulation studies for the Mini-EUSO detector

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    Mini-EUSO is a mission of the JEM-EUSO program flying onboard the International Space Station since August 2019. Since the first data acquisition in October 2019, more than 35 sessions have been performed for a total of 52 hours of observations. The detector has been observing Earth at night-time in the UV range and detected a wide variety of transient sources all of which have been modelled through Monte Carlo simulations. Mini-EUSO is also capable of detecting meteors and potentially space debris and we performed simulations for such events to estimate their impact on future missions for cosmic ray science from space. We show here examples of the simulation work done in this framework to analyse the Mini-EUSO data. The expected response of Mini-EUSO with respect to ultra high energy cosmic ray showers has been studied. The efficiency curve of Mini-EUSO as a function of primary energy has been estimated and the energy threshold for Cosmic Rays has been placed to be above 1021^{21} eV. We compared the morphology of several transient events detected during the mission with cosmic ray simulations and excluded that they can be due to cosmic ray showers. To validate the energy threshold of the detector, a system of ground based flashers is being used for end-to-end calibration purposes. We therefore implemented a parameterisation of such flashers into the JEM-EUSO simulation framework and studied the response of the detector with respect to such sources

    Human VDAC pseudogenes: an emerging role for VDAC1P8 pseudogene in acute myeloid leukemia

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    Background Voltage-dependent anion selective channels (VDACs) are the most abundant mitochondrial outer membrane proteins, encoded in mammals by three genes, VDAC1, 2 and 3, mostly ubiquitously expressed. As ’mitochondrial gatekeepers’, VDACs control organelle and cell metabolism and are involved in many diseases. Despite the presence of numerous VDAC pseudogenes in the human genome, their significance and possible role in VDAC protein expression has not yet been considered. Results We investigated the relevance of processed pseudogenes of human VDAC genes, both in physiological and in pathological contexts. Using high-throughput tools and querying many genomic and transcriptomic databases, we show that some VDAC pseudogenes are transcribed in specific tissues and pathological contexts. The obtained experimental data confirm an association of the VDAC1P8 pseudogene with acute myeloid leukemia (AML). Conclusions Our in-silico comparative analysis between the VDAC1 gene and its VDAC1P8 pseudogene, together with experimental data produced in AML cellular models, indicate a specific over-expression of the VDAC1P8 pseudogene in AML, correlated with a downregulation of the parental VDAC1 gene. Keywords Pseudogene, Voltage-dependent anion selective channels (VDAC

    Highly-parallelized simulation of a pixelated LArTPC on a GPU

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    The rapid development of general-purpose computing on graphics processing units (GPGPU) is allowing the implementation of highly-parallelized Monte Carlo simulation chains for particle physics experiments. This technique is particularly suitable for the simulation of a pixelated charge readout for time projection chambers, given the large number of channels that this technology employs. Here we present the first implementation of a full microphysical simulator of a liquid argon time projection chamber (LArTPC) equipped with light readout and pixelated charge readout, developed for the DUNE Near Detector. The software is implemented with an end-to-end set of GPU-optimized algorithms. The algorithms have been written in Python and translated into CUDA kernels using Numba, a just-in-time compiler for a subset of Python and NumPy instructions. The GPU implementation achieves a speed up of four orders of magnitude compared with the equivalent CPU version. The simulation of the current induced on 10^3 pixels takes around 1 ms on the GPU, compared with approximately 10 s on the CPU. The results of the simulation are compared against data from a pixel-readout LArTPC prototype

    The UHECR dipole and quadrupole in the latest data from the original Auger and TA surface detectors

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    The sources of ultra-high-energy cosmic rays are still unknown, but assuming standard physics, they are expected to lie within a few hundred megaparsecs from us. Indeed, over cosmological distances cosmic rays lose energy to interactions with background photons, at a rate depending on their mass number and energy and properties of photonuclear interactions and photon backgrounds. The universe is not homogeneous at such scales, hence the distribution of the arrival directions of cosmic rays is expected to reflect the inhomogeneities in the distribution of galaxies; the shorter the energy loss lengths, the stronger the expected anisotropies. Galactic and intergalactic magnetic fields can blur and distort the picture, but the magnitudes of the largest-scale anisotropies, namely the dipole and quadrupole moments, are the most robust to their effects. Measuring them with no bias regardless of any higher-order multipoles is not possible except with full-sky coverage. In this work, we achieve this in three energy ranges (approximately 8--16 EeV, 16--32 EeV, and 32--‚ąě EeV) by combining surface-detector data collected at the Pierre Auger Observatory until 2020 and at the Telescope Array (TA) until 2019, before the completion of the upgrades of the arrays with new scintillator detectors. We find that the full-sky coverage achieved by combining Auger and TA data reduces the uncertainties on the north-south components of the dipole and quadrupole in half compared to Auger-only results
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