Neutron Veto of XENONnT: final construction design of the system and extensive study and calibration of the PMTs.

Numerous and convincing are the experimental evidences that led to the believe that most of the Universe is constituted by the so-called Dark Matter (DM). Its research has attracted many experimental efforts to the point of being considered the greatest mystery of physics. The most promising candidates to DM are generically named as WIMPs, an acronym for Weakly Interacting Massive Particles.The detectors that have reached the most competitive sensitivity levels have in common the characteristics of being built with ultrapure materials and located underground, shielded from cosmic rays. The XENON project,located at the Laboratori Nazionali del Gran Sasso (LNGS). The XENON1T experiment employed a dual-phase Time Projection Chamber (TPC) with 2t of xenon active mass. The next step of the detector is XENONnT, and is currently in the final assembling stage. With a bigger TPC containing 6t of xenon active mass, the main goal is to improve the detection potential for WIMPs by increasing the sensitivity of one order of magnitude in five years of data taking. That result can be achieved only with a substantial background lowering attained with a reduction of the contaminants of the xenon as well as of the detector materials and finally, with the Neutron Veto system (nVeto); the latter is a detector which tags the radiogenic neutrons coming from the materials of the experiment. The nVeto will employ the gadolinium-loaded water technology to significantly enhance the neutron capture cross-section. It will be instrumented with 120 8'' Hamamatsu R5912 photomultipliers (PMT) featuring high quantum efficiency and low radioactivity. Most of the work done to design and realize the nVeto is the argument of this thesis. In addition, an extensive study of the nVeto PMT performance has been done in a dedicated experimental setup at the LNGS. The complete description of the setup,as well as the results of the nVeto PMT tests, is the other big topic of this thesis

Venous Thromboembolism in Liver Cirrhosis: An Emerging Issue

Venous thromboembolism (VTE) carries a high morbidity and mortality and leads to a substantial economic burden. From the traditional perspectives, liver cirrhosis tends to bleeding but not VTE. However, modern concepts suggest that liver cirrhosis is also at a risk of VTE. The pooled incidence and prevalence of VTE in liver cirrhosis are 1% (95% confidence interval: 0.7–1.3%) and 1% (95% confidence interval: 0.7–1.2%), respectively. Evidence indicates that a higher international normalized ratio and a lower albumin should be associated with a higher probability of VTE in liver cirrhosis. Additionally, the presence of VTE significantly worsens the outcomes of liver cirrhosis

Further evidence of the contribution of the ear canal to directional hearing: design of a compensating filter

It has been proven, and it is well documented in literature, that the directional response in HRTFs comes largely from the effect of the pinnae. However, few studies have analysed the contribution given by the remaining part of the external ear, particularly the ear canal. This work investigates the directionally dependent response of the modelled ear canal of a dummy head, assuming that the behaviour of the external ear is sufficiently linear to be approximated by an LTI system. In order to extract the ear canal\u27s transfer function, two critical microphone placements (at the eardrum and at the beginning of the cavum conchae) have been used. The system has been evaluated in several positions, along the azimuth plane and at different degrees of elevation. The results point out a non-negligible directional dependence that is well within the normal hearing range; based on these findings, physical models of the ear canal have been analysed and evaluated. We have also considered the practical application to binaural listening, and the colouration originated by the superimposition of the contribution of two ear canals (the listener\u27s and the dummy head\u27s). A compensating FIR filter with arbitrary frequency response is discussed as a possible fix

Misure di guadagno di fotomoltiplicatori per il sistema di veto di neutroni dell'esperimento XENONnT

Diverse osservazioni, su scala astronomica e cosmologica, suggeriscono l'esistenza di Materia Oscura e che questa componga quasi il 90% della materia nell'Universo. Le particelle candidate più promettenti sono le Weakly Interacting Massive Particle. La loro rivelazione è difficile a causa della piccola sezione d'urto prevista; l'osservazione di Materia Oscura necessita quindi di rivelatori ultra puri e ultrasensibili, situati in ambienti in cui i segnali di fondo possano essere ridotti. Il progetto XENON, ai Laboratori Nazionali del Gran Sasso, si pone l'obiettivo di rivelare direttamente le interazioni della Materia Oscura con rivelatori costituiti da una Time Projection Chamber contenente Xeno. La fase attuale del progetto è XENON1T; i primi risultati non hanno evidenziato eventi dovuti a Materia Oscura, permettendo invece di fissare un limite per la sezione d'urto WIMP-nucleo, indipendente dallo spin e di migliorare quelli precedentemente ottenuti. Con lo scopo di aumentare ulteriormente la sensibilità, ed eventualmente confermare un'osservazione da parte di XENON1T, la collaborazione sta lavorano alla fase successiva, prevista per il 2019: XENONnT. Per ridurre il fondo dovuto a neutroni generati dai materiali del rivelatore è in progetto un sistema di Veto di Neutroni basato su scintillatore liquido dopato con Gadolinio (Gd). Tale rivelatore è completato da 120 Fotomoltiplicatori, ovvero dispositivi in grado di convertire il segnale luminoso in un segnale di corrente analizzabile e amplificabile. In questo lavoro di tesi saranno riportati i risultati di primi test di funzionalità di PMT 8" Hamamatsu R5912-100WA-D30, effettuati presso i laboratori dell'Università e della Sezione INFN di Bologna. In particolare è stato misurato il guadagno di tre PMT campione e lo si è confrontato con i valori forniti dalla casa produttrice, allo scopo di valutare un possibile utilizzo dei PMT nel futuro Veto di Neutroni di XENONnT

Stellar Mass Function of Active and Quiescent Galaxies via the Continuity Equation

The continuity equation is developed for the stellar mass content of galaxies and exploited to derive the stellar mass function of active and quiescent galaxies over the redshift range z â¼ 0-8. The continuity equation requires two specific inputs gauged from observations: (i) the star formation rate functions determined on the basis of the latest UV+far-IR/submillimeter/radio measurements and (ii) average star formation histories for individual galaxies, with different prescriptions for disks and spheroids. The continuity equation also includes a source term taking into account (dry) mergers, based on recent numerical simulations and consistent with observations. The stellar mass function derived from the continuity equation is coupled with the halo mass function and with the SFR functions to derive the star formation efficiency and the main sequence of star-forming galaxies via the abundance-matching technique. A remarkable agreement of the resulting stellar mass functions for active and quiescent galaxies of the galaxy main sequence, and of the star formation efficiency with current observations is found; the comparison with data also allows the characteristic timescales for star formation and quiescence of massive galaxies, the star formation history of their progenitors, and the amount of stellar mass added by in situ star formation versus that contributed by external merger events to be robustly constrained. The continuity equation is shown to yield quantitative outcomes that detailed physical models must comply with, that can provide a basis for improving the (subgrid) physical recipes implemented in theoretical approaches and numerical simulations, and that can offer a benchmark for forecasts on future observations with multiband coverage, as will become routinely achievable in the era of JWST

Ecomorphology and bone microstructure of Proterochampsia from the Chañares Formation

Proterochampsians are a South American endemic group of non-archosaurian archosauriforms with morphological characteristics recollecting Recent crocodilians, and therefore have been proposed as aquatic species. However, this has not been based on careful examination of anatomical and histological features. We provide a review of the morphological and histological evidence present in the skeleton of proterochampsids and discuss its implications for inferring the lifestyles of these organisms. Anatomical features such as a secondary palate, marginal dentition, palatine teeth, morphology of the tail, limb modification, and dermal armor are reviewed, and details of histological structures are described based on bone thin sections. Histological examination reveals a predominance of fibrolamellar bone tissue, suggesting rapid periosteal osteogenesis and therefore overall fast bone growth. The existence of discontinuities (LAGs) demonstrates that these animals responded to changes in their environment. Ecomorphological features do not provide definitive evidence for the lifestyles of proterochampsids, but allow us to propose a terrestrial/amphibious condition. The same is true of the histological features, particularly compactness of the bone.Fil: Arcucci, Andrea Beatriz. Universidad Nacional de San Luis; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; ArgentinaFil: Previtera, Maria Elena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Mancuso, Adriana Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; Argentin

RT-Bench: an Extensible Benchmark Framework for the Analysis and Management of Real-Time Applications

Benchmarking is crucial for testing and validating any system, even more so in real-time systems. Typical real-time applications adhere to well-understood abstractions: they exhibit a periodic behavior, operate on a well-defined working set, and strive for stable response time avoiding non-predicable factors such as page faults. Unfortunately, available benchmark suites fail to reflect key characteristics of real-time applications. Practitioners and researchers must resort to either benchmark heavily approximated real-time environments, or to re-engineer available benchmarks to add -- if possible -- the sought-after features. Additionally, the measuring and logging capabilities provided by most benchmark suites are not tailored "out-of-the-box" to real-time environments, and changing basic parameters such as the scheduling policy often becomes a tiring and error-prone exercise. In this paper, we present RT-bench, an open-source framework adding standard real-time features to virtually any existing benchmark. Furthermore, RT-bench provides an easy-to-use, unified command line interface to customize key aspects of the real-time execution of a set of benchmarks. Our framework is guided by four main criteria: 1) cohesive interface, 2) support for periodic application behavior and deadline semantics, 3) controllable memory footprint, and 4) extensibility and portability. We have integrated within the framework applications from the widely used SD-VBS and IsolBench suites. We showcase a set of use-cases that are representative of typical real-time system evaluation scenarios and that can be easily conducted via RT-Bench.Comment: 11 pages, 12 figures; code available at https://gitlab.com/rt-bench/rt-bench, documentation available at https://rt-bench.gitlab.io/rt-bench

Huellas de tetrápodos del Triásico Medio del extremo sur de América del Sur

In South America, tetrapod footprints of Middle Triassic age were only described from the Cuyana (Cerro de las Cabras Formation) and Ischigualasto-Villa Unión (Los Rastros Formation) basins in west-central Argentina. They are scarce and remain mostly undescribed. Their significance and the putative trackmakers are identified and discussed within a phylogenetic context in the present contribution. Several groups of tetrapods are suggested to be represented, as non-mammalian therapsids, crurotarsal archosaurs and putative dinosaurs. The presence of crurotarsal archosaurs and non-mammalian therapsids in Cerro de las Cabras Formation suggests a tetrapod fauna more diverse than that documented by the known body fossil record. The ichnites described from the Los Rastros Formation are, until now, the only evidence of amniotes in the Ischigualasto-Villa Unión Basin during the deposition of these levels. They indicate the presence of putative dinosaurs, crurotarsal archosaurs and non-mammalian therapsids, which are already well represented in the rest of the sequence by skeletal remains.En América del Sur, huellas de tetrápodos del Triásico Medio sólo se conocen en niveles de las cuencas Cuyana (Formación Cerro de las Cabras) e Ischigualasto-Villa Unión (Formación Los Rastros), en el centro-oeste de Argentina. Las huellas son escasas y la mayoría de los especímenes no están descriptos. En el presente trabajo el significado de estas huellas y sus supuestos generadores son discutidos en un contexto filogenético. Así, varios grupos de tetrápodos han sido identificados como terápsidos no mamalianos, arcosaurios crurotarsales y probables dinosaurios. La presencia de arcosaurios crurotarsales y terápsidos no mamalianos en niveles de la Formación Cerro de las Cabras sugiere una fauna más diversa que lo que indica el registro de restos fósiles esqueletarios conocidos para los mismos niveles. Las icnitas de la Formación Los Rastros son hasta el momento la única evidencia de amniotas en la Cuenca de Ischigualasto-Villa Unión durante la depositación de dichos niveles. Ellas indican la existencia de probables dinosaurios, arcosaurios crurotarsales y terápsidos no mamalianos, bien representados en el resto de la sequencia por restos esqueletarios.Fil: Marsicano, Claudia Alicia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; Argentina. Universidad de Buenos Aires. Facultad de Cs.exactas y Naturales. Departamento de Geología. Cátedra de Paleontología de Vertebrados; ArgentinaFil: Arcucci, Andrea Beatriz. Universidad Nacional de San Luis; ArgentinaFil: Mancuso, Adriana Cecilia. Universidad de Buenos Aires. Facultad de Cs.exactas y Naturales. Departamento de Geología. Cátedra de Paleontología de Vertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Caselli, Alberto Tomás. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias Geológicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Plant taphonomy in a lake affected by volcanism (Agua de la Zorra formation, Upper Triassic) Mendoza, Argentina

Volcanic eruptions have an impact on the paleoecology of plant communities and their preservation in the fossil record. The aim of this contribution is to evaluate the influence of volcanism on plant preservation in lacustrine settings via systematic sampling and chemical analyses of fossil plants in the Upper Triassic Agua de la Zorra Formation, of the Argentinian Cuyana Basin. Plant remains are not uniformly preserved throughout the Agua de la Zorra Formation and their stratigraphic distribution reflects the original spatial pattern of the plant communities. SEM-EDX analyses was used to demonstrate how volcanism affected diagenesis of the plant remains. Eight taphonomic modes were determined from biostratinomic analysis, and three preservational modes from the chemical features observed in the SEM-EDX spectra. The three preservation modes recognized by SEM-EDX analysis are more likely linked to diagenesis and are not equivalent to the taphonomic modes described based on the biostratinomic features. The Agua de la Zorra paleolake preferentially preserved plant material because of anoxic conditions in deeper parts of the lake, and a high sedimentation rate in proximal near-shore facies. The plant remains are most abundant in sandy facies deposited by high-energy flows but there is no evidence that these flows were pyroclastic nor that the plant remains were generated by volcanic trauma.Fil: Pedernera, Tomas Ezequiel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Mancuso, Adriana Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Benavente, Cecilia Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Ottone, Eduardo Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; Argentin