A Consortium between four LHC Computing Centers (Bari, Milano, Pisa and Trieste) has been formed in 2010 to prototype Analysis-oriented facilities for CMS data analysis, profiting from a grant from ...the Italian Ministry of Research. The Consortium aims to realize an ad-hoc infrastructure to ease the analysis activities on the huge data set collected at the LHC Collider. While “Tier2” Computing Centres, specialized in organized processing tasks like Monte Carlo simulation, are nowadays a well established concept, with years of running experience, site specialized towards end user chaotic analysis activities do not yet have a defacto standard implementation. In our effort, we focus on all the aspects that can make the analysis tasks easier for a physics user not expert in computing. On the storage side, we are experimenting on storage techniques allowing for remote data access and on storage optimization on the typical analysis access patterns. On the networking side, we are studying the differences between flat and tiered LAN architecture, also using virtual partitioning of the same physical networking for the different use patterns. Finally, on the user side, we are developing tools and instruments to allow for an exhaustive monitoring of their processes at the site, and for an efficient support system in case of problems. We will report about the results of the test executed on different subsystem and give a description of the layout of the infrastructure in place at the site participating to the consortium.
Over the last years interest in using time-of-flight-based Positron Emission Tomography (TOF-PET) systems has significantly increased. High time resolution in such PET systems is a powerful tool to ...improve signal to noise ratio and therefore to allow smaller exposure rates for patients as well as faster image reconstruction. Improvement in coincidence time resolution (CTR) in PET systems to the level of 200ps FWHM requires the optimization of all parameters in the photon detection chain influencing the time resolution: crystal, photodetector and readout electronics. After reviewing the factors influencing the time resolution of scintillators, we will present in this paper the light yield and CTR obtained for different scintillator types (LSO:Ce, LYSO:Ce, LGSO:Ce, LSO:Ce:0.4Ca, LuAG:Ce, LuAG:Pr) with different cross-sections, lengths and reflectors. Whereas light yield measurements were made with a classical PMT, all CTR tests were performed with Hamamatsu-MPPCs or SiPMs S10931-050P. The CTR measurements were based on the time-over-threshold method in a coincidence setup using the ultra fast amplifier-discriminator chip NINO and a fast oscilloscope. Strong correlations between light yield and CTR were found. Excellent results have been obtained for LYSO crystals of 2×2×10mm 3 and LYSO pixels of 0.75×0.75×10mm 3 with a CTR of 175ps and 188ps FWHM, respectively.
Bayesian semiparametric logit models are fitted to grouped data related to in-hospital survival outcome of patients hospitalized with an ST-segment elevation myocardial infarction diagnosis. ...Dependent Dirichlet process priors are considered for modeling the random-effects distribution of the grouping factor (hospital of admission), to provide a cluster analysis of the hospitals. The clustering structure is highlighted through the optimal random partition that minimizes the posterior expected value of a suitable loss function. There are two main goals of the work: to provide model-based clustering and ranking of the providers according to the similarity of their effect on patients' outcomes, and to make reliable predictions on the survival outcome at the patient's level, even when the survival rate itself is strongly unbalanced. The study is within a project, named the 'Strategic program of Regione Lombardia', and is aimed at supporting decisions in healthcare policies.
The South Falkland Basin hosts a working petroleum system, as well as one of the most recently discovered gas hydrate provinces of the South Atlantic Ocean. Using three-dimensional reflection seismic ...data, a series of bottom-simulating reflections (BSRs) are interpreted within two contrasting settings, (1) the thrust-cored anticlines, developed by the oblique convergence of the Scotia and the South American plates, and (2) the foreland basin, formed to the north of this plate boundary. These BSRs are interpreted as the base of the gas hydrate stability zone, and are associated with seismic indicators of underlying free-gas accumulations and overlying hydrate-bearing sediments.
In the foreland basin, the BSR is laterally continuous for tens of kilometres, whereas in the fold belt, BSR occurrences are restricted to limited portions of the thrust-cored anticline crests. These observations, calibrated with sedimentological analyses and gas geochemistry, argue that the gas source for the gas hydrates within the thrust-cored anticlines is unrelated to in-situ microbial generation of methane, but instead is associated with the vertical seepage of thermogenic fluids from deeper cores of the anticlines. In contrast, the nature of the sediments in the foreland basin appears more favourable for the generation of shallow microbial methane.
This study highlights that, in specific tectonic and depositional environments, the character of the BSR observed on reflection seismic data with the limited support of in-situ data, can be used to predict the most likely source of natural gas hydrate systems.
•The South Falkland Basin hosts one of the most recently discovered gas hydrate provinces of the south Atlantic Ocean.•Thermogenic and microbial gas produce contrasting and diverse gas hydrate deposits.•The distribution of the BSR can be sufficient to understand the origin of the gas sourcing the formation of gas hydrates.
We constrain orientations of the horizontal stress field from borehole image data in a transect across the Hikurangi Subduction Margin. This region experiences NW‐SE convergence and is the site of ...recurrent slow slip events. The direction of the horizontal maximum stress is E‐W at an active splay thrust fault near the subduction margin trench. This trend changes to NNW‐SSE in a forearc trench slope basin on the offshore accretionary wedge, and to NE‐SW in the onshore forearc. Multiple, tectonic, and geological processes, either individually or in concert, may explain this variability. The observed offshore to onshore stress rotation may reflect a change from dominantly compressional tectonics at the deformation front, to a strike‐slip and/or extensional tectonic regime closer to the Taupo Volcanic Zone, further inland. In addition, the offshore stress may be affected by topography and/or stress rotation around subducting seamounts, and/or temporal stress changes during the slow slip cycle.
Plain Language Summary
Using geophysical images captured from the inside of boreholes drilled across the Hikurangi Subduction Margin, an area that experiences slow earthquakes, we describe variability in the direction of modern day maximum horizontal tectonic forces (stress) at this collisional plate boundary. Changes in the direction of maximum horizontal stress occur as you move from the plate boundary toward the onshore region of New Zealand's North Island. We suggest a range of possible tectonic and geological processes that either individually or in concert may explain our observed stress direction variations. This includes changing tectonic regimes as you move away from the plate boundary, topography, and effects on the stress field caused by the presence of subducting seamounts, and changing stress conditions related to the intermittent activity of slow earthquakes.
Key Points
Maximum horizontal stress directions vary in a transect across the Hikurangi Subduction Margin
Stress orientations suggest a change occurs moving from offshore to onshore associated with changing dominant tectonic regime
Offshore stress variation may be caused by a number of specific tectonic and geological causes
Enhancing Timing Performance of Heterostructures with Double-Sided Readout Pagano, F.; Cates, J. W.; Choong, W.-S. ...
2023 IEEE Nuclear Science Symposium, Medical Imaging Conference and International Symposium on Room-Temperature Semiconductor Detectors (NSS MIC RTSD),
2023-Nov.-4
Conference Proceeding
Heterostructured scintillators are gaining ground as a possible solution to the trade-off between the high sensitivity and fast timing of detectors for time-of-flight positron emission tomography ...(TOF-PET). They consist of stacks of alternating layers of two materials with complementary properties: high stopping power and ultrafast timing. The fast emitter improves the timing performance of the detector. However, layering is a limiting factor for the best achievable time resolution, as it worsens light transport. This effect can be mitigated by increasing light collection and retrieving the depth-of-interaction (DOI) information. The double-sided readout can meet both requirements.In this work, we use high-frequency electronics in a double-sided readout configuration with a 3x3x20mm 3 BGO&EJ232 heterostructure. By selecting the photopeak events, we were able to achieve a DOI resolution of 6.4±0.5mm 3 . The improvement in coincidence time resolution (CTR), compared to the single-sided readout, is 18% for all photopeak events (from 256±8 to 211±6ps) and 36% when considering only photopeak events that share the energy between the two materials (from 200±6 to 128±4ps).
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