45 research outputs found

    The loess deposits of Buca Dei Corvi section (Central Italy): Revisited

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    Loess deposits have been described in the past for the upper section of Buca Dei Corvi succession (Central Italy). In this paper the depositswere re-analysed to clarify the depositional environment and to attempt a paleoclimate reconstruction. Two radiocarbon dates on pedogenic carbonate constrain the ages to the Late Glacial, and are consistent with previous OSL dating of the top of the succession. The non-marine mollusc assemblage shows typical character of cold and dry climatic conditions, testified by strong oligotypical composition. Mineralogy and geochemistry of the sediments indicate the abundant presence of exotic quartz mineral which can be explained only by wind transport. Probably,wind transportwas also responsible of deposition of carbonatewhich then dissolved and re-precipitated producing pedogenic concretions. Stable isotopes (13C/12C and 18O/16O ratios) of the concretions are consistent with a climate drier than present conditions, with an environment characterized by sparse vegetation

    Características geoquímicas de las cuñas de hielo en Puerto Deseado (Santa Cruz, Argentina): implicancias paleoambientales y cronológicas

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    Ground wedge structures of cryogenic origin are common in the Quaternary sediments along the coast of the Patagonia, and their formation is related to climatic cold events experienced by this area in the Late Quaternary. The infilling sediments of two wedges generations were analyzed in the area of Puerto Deseado. Bulk chemistry (major elements), X-ray diffraction (XRD), morphoscopic observations with Scanning Electronic Microscope (SEM) and chemical analyses of volcanic glass shards were undertaken to provide indications about infilling sediment provenience, along with chronological constraint for wedge formation. Bulk chemistry and XRD patterns indicate a significant SiO2- enriched composition of the sediment infilling compared to the most of the loess deposits of the North Argentina and the present day dust originated in Patagonia. This was interpreted as due to the nature of the bedrock present over the Deseado Massif. SEM morphoscopic characteristics of glass shards evidence typical aeolian reworking features, with impact structures and indented edges of the volcanic fragments. Chemical analyses of the glass shards indicate that they were probably generated by the H0 eruption (17,300-17,400 cal yr BP) of the Hudson volcano. Volcanological data indicate that H0 eruption dispersed toward NE, but volcanic glasses were available for reworking due to a WNW component in the western wind direction. Over the Deseado Massif structural high the glass shards mixed with sediments enriched in SiO2, and were eventually deflated further to SE reaching the present coastal area and infilling the frost cracks. The age of the glass shards (17,300-17,400 cal yr BP) and that of the sandy layer affected by cryogenic structures (14,670±750 yr BP) well constrain to the Late Glacial both wedge generations.Las cuñas de hielo son estructuras comunes en sedimentos cuaternarios a lo largo de la costa patagónica, y su formación está relacionada con eventos climáticos fríos experimentados en esta área en el Cuaternario Tardío. Se analizaron sedimentos que rellenan dos generaciones de cuñas de hielo en la zona de Puerto Deseado. Análisis químicos de elementos mayores, difractometría de rayos X (DRX), observaciones con microscopio electrónico de barrido (SEM) y análisis químico de fragmentos de vidrio volcánico contenidos en el sedimento que rellena las cuñas proporcionaron información sobre la precedencia del relleno, además de inferir antecedentes cronológicos sobre su formación. La composición química del sedimento y la difracción de rayos X indican una composición enriquecida en SiO2 en comparación con la mayoría de los depósitos de loess del norte de Argentina y el polvo actual originado en la Patagonia. Esto fue interpretado como producto de la influencia de las rocas que constituyen el macizo del Deseado. Las características morfológicas de los fragmentos de vidrio evidencian rasgos típicos de retrabajo eólico, con presencia de estructuras de impacto y bordes dentados. Los análisis químicos de los fragmentos de vidrio son compatibles con un origen en la erupción H0 (17.300-17.400 cal yr BP) del volcán Hudson. Datos volcanológicos indican que la erupción H0 originó una pluma de dispersión hacia el NE. El material volcánico dispersado por esta erupción quedó disponible para ser retrabajado por una componente WNW de los vientos del W dominantes en la zona. Sobre el macizo del Deseado, los fragmentos de vidrio se mezclaron con sedimentos ricos en SiO2 y fueron adicionalmente, enriquecidos en este elemento hasta alcanzar el área de costa actual, rellenando las cuñas de hielo. La edad de los fragmentos de vidrio (17.300-17.400 cal yr BP) y de la capa arenosa afectada por las estructuras criogénicas (14.670±750 años BP) limitan al glacial tardío la formación de ambas generaciones de cuñas.Centro de Estudios Integrales de la Dinámica Exógen

    First observation of the rare decay mode K+μ+νμμ+μK^+ \to \mu^+ \nu_{\mu} \mu^+ \mu^- in the NA62 experiment at CERN SPS

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    The leptonic kaon decay K+μ+νμμ+μK^+ \to \mu^+ \nu_{\mu} \mu^+ \mu^- is among the clean modes to explore the flavour structure of the Standard Model. From the theoretical point of view, Chiral Perturbation Theory allows for an accurate calculation of the branching ratio and decay distributions. Experimentally, the decay mode has never been measured and only a limit on the branching ratio has been set so far. In this work, the selection of the K+μ+νμμ+μK^+ \to \mu^+ \nu_{\mu} \mu^+ \mu^- decays is presented, the abundant background from K+π+π+πK^+ \to \pi^+ \pi^+ \pi^- decays is evaluated and a preliminary measurement of the branching ratio is obtained from a subset of the available data sample recorded by the NA62 experiment at the CERN SPS in 2017

    The Data Acquisition System of the Na62 Experiment at Cern

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    The aim of the NA62 experiment is to study the extreme rare kaon decay K+ ? π+vv and to measure its branching ratio with a 10% accuracy. In order to do so, a very high intensity beam from the CERN SPS is used to produce charged kaons whose decay products are detected by many detectors installed along a 60 m decay region. The NA62 Data Acquisition system (DAQ) exploits a multi-level trigger system; following a Level0 (L0) trigger decision, 1 MHz data rate from about 60 sources is read by a PC-farm, the partial event is built and then passed through a series of Level1 (L1) algorithms to further reduce the trigger rate. Events passing this level are completed with the missing, larger, data sources (~400 sources) at the rate of 100 KHz. The DAQ is built around a high performance ethernet network interconnecting the detectors to a farm of 30 servers. After an overall description of the system design and the main implementation choices that allowed to reach the required performance and functionality, this paper describes the overall behaviour of the DAQ in the 2017 data taking period. It then concludes with an outlook of possible improvements and upgrades that may be applied to the system in the future

    Geomorphology of the Liera catchment (Dolomites, NE Italy): understanding landscape response to an extreme event

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    ABSTRACTGeomorphological field surveys and mapping have been carried out in a catchment of the Dolomites (eastern Italian Alps) as part of a research project aiming at the assessment of sediment availability for mass wasting in mountain environments. The study area is the Liera catchment which was severely affected by a high-intensity, regional-scale storm named ‘Vaia’ (27–30 October 2018), which induced relevant morphological changes, caused a major flood in the main stream and triggered debris flows in many tributaries. This contribution gives a snapshot of the present-day state of the study area to improve the understanding of such a landscape by characterizing the processes that control its geomorphological spatio-temporal dynamics and evolution

    DAQling: an open-source data acquisition framework

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    The Data AcQuisition (DAQ) software for most applications in high energy physics is composed of common building blocks, such as a networking layer, plug-in loading, configuration, and process management. These are often re-invented and developed from scratch for each project or experiment around specific needs. In some cases, time and available resources can be limited and make development requirements difficult or impossible to meet. Moved by these premises, our team developed an open-source lightweight C++ software framework called DAQling, to be used as the core for the DAQ systems of small and medium-sized experiments and collaborations. The framework offers a complete DAQ ecosystem, including a communication layer based on the widespread ZeroMQ messaging library, configuration management based on the JSON format, control of distributed applications, extendable operational monitoring with web-based visualisation, and a set of generic utilities. The framework comes with minimal dependencies, and provides automated host and build environment setup based on the Ansible automation tool. Finally, the end-user code is wrapped in so-called “Modules”, that can be loaded at configuration time, and implement specific roles. Several collaborations already chose DAQling as the core for their DAQ systems, such as FASER, RD51, and NA61/SHINE. We will present the framework and project-specific implementations and experiences

    DAQling: an open-source data acquisition framework

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    The Data AcQuisition (DAQ) software for most applications in high energy physics is composed of common building blocks, such as a networking layer, plug-in loading, configuration, and process management. These are often re-invented and developed from scratch for each project or experiment around specific needs. In some cases, time and available resources can be limited and make development requirements difficult or impossible to meet. Moved by these premises, our team developed an open-source lightweight C++ software framework called DAQling, to be used as the core for the DAQ systems of small and medium-sized experiments and collaborations. The framework offers a complete DAQ ecosystem, including a communication layer based on the widespread ZeroMQ messaging library, configuration management based on the JSON format, control of distributed applications, extendable operational monitoring with web-based visualisation, and a set of generic utilities. The framework comes with minimal dependencies, and provides automated host and build environment setup based on the Ansible automation tool. Finally, the end-user code is wrapped in so-called “Modules”, that can be loaded at configuration time, and implement specific roles. Several collaborations already chose DAQling as the core for their DAQ systems, such as FASER, RD51, and NA61/SHINE. We will present the framework and project-specific implementations and experiences

    Depth of interaction determination in monolithic scintillator with double side SiPM readout

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    Background: Monolithic scintillators read out by arrays of photodetectors represent a promising solution to obtain high spatial resolution and the depth of interaction (DOI) of the annihilation photon. We have recently investigated a detector geometry composed of a monolithic scintillator readout on two sides by silicon photomultiplier (SiPM) arrays, and we have proposed two parameters for the DOI determination: the difference in the number of triggered SiPMs on the two sides of the detector and the difference in the maximum collected signal on a single SiPM on each side. This work is focused on the DOI calibration and on the determination of the capability of our detector. For the DOI calibration, we studied a method which can be implemented also in detectors mounted in a full PET scanner. We used a PET detector module composed of a monolithic 20 × 20 × 10 mm3 LYSO scintillator crystal coupled on two opposite faces to two arrays of SiPMs. On each side, the scintillator was coupled to 6 × 6 SiPMs. In this paper, the two parameters previously proposed for the DOI determination were calibrated with two different methods. The first used a lateral scan of the detector with a collimated 511 keV pencil beam at steps of 0.5 mm to study the detector DOI capability, while the second used the background radiation of the 176Lu in the scintillator. The DOI determination capability was tested on different regions of the detector using each parameter and the combination of the two. Results: With both parameters for the DOI determination, in the lateral scan, the bias between the mean reconstructed DOI and the real beam position was lower than 0.3 mm, and the DOI distribution had a standard deviation of about 1.5 mm. When using the calibration with the radioactivity of the LYSO, the mean bias increased of about 0.2 mm but with no degradation of the standard deviation of the DOI distribution. Conclusions: The two parameters allow to achieve a DOI resolution comparable with the state of the art, giving a continuous information about the three-dimensional interaction position of the scintillation. These results were obtained by using simple estimators and a detector scalable to a whole PET system. The DOI calibration obtained using lutetium natural radioactivity gives results comparable to the other standard method but appears more readily applicable to detectors mounted in a full PET scanner

    Changes in Right Ventricular–to–Pulmonary Artery Coupling After Transcatheter Edge-to-Edge Repair in Secondary Mitral Regurgitation

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    Background: Preprocedural right ventricular–to–pulmonary artery (RV-PA) coupling is a major predictor of outcome in patients with secondary mitral regurgitation (SMR) undergoing transcatheter edge-to-edge mitral valve repair (M-TEER). However, clinical significance of changes in RV-PA coupling after M-TEER is unknown. Objectives: The aim of this study was to evaluate changes in RV-PA coupling after M-TEER, their prognostic value, and predictors of improvement. Methods: This was a retrospective observational study, including patients undergoing successful M-TEER (residual mitral regurgitation ≤2+ at discharge) for SMR at 13 European centers and with complete echocardiographic data at baseline and short-term follow-up (30-180 days). RV-PA coupling was assessed with the use of echocardiography as the ratio of tricuspid annular plane systolic excursion to pulmonary artery systolic pressure (TAPSE/PASP). All-cause death was assessed at the longest available follow-up starting from the time of the echocardiographic reassessment. Results: Among 501 patients included, 331 (66%) improved their TAPSE/PASP after M-TEER (responders) at short-term follow-up (median: 89 days; IQR: 43-159 days), whereas 170 (34%) did not (nonresponders). Lack of previous cardiac surgery, low postprocedural mitral mean gradient, low baseline TAPSE, high baseline PASP, and baseline tricuspid regurgitation were independently associated with TAPSE/PASP improvement after M-TEER. Compared with nonresponders, responders had lower New York Heart Association functional class and less heart failure hospitalizations at short-term follow-up. Improvement in TAPSE/PASP was independently associated with reduced risk of mortality at long-term follow-up (584 days; IQR: 191-1,243 days) (HR: 0.65 [95% CI: 0.42-0.92]; P = 0.017). Conclusions: In patients with SMR, improvement in TAPSE/PASP after successful M-TEER is predicted by baseline clinical and echocardiographic variables and postprocedural mitral gradient, and is associated with a better outcome
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