1,947 research outputs found
A fast - Monte Carlo toolkit on GPU for treatment plan dose recalculation in proton therapy
In the context of the particle therapy a crucial role is played by Treatment Planning Systems (TPSs), tools aimed to compute and optimize the tratment plan. Nowadays one of the major issues related to the TPS in particle therapy is the large CPU time needed. We developed a software toolkit (FRED) for reducing dose recalculation time by exploiting Graphics Processing Units (GPU) hardware. Thanks to their high parallelization capability, GPUs significantly reduce the computation time, up to factor 100 respect to a standard CPU running software. The transport of proton beams in the patient is accurately described through Monte Carlo methods. Physical processes reproduced are: Multiple Coulomb Scattering, energy straggling and nuclear interactions of protons with the main nuclei composing the biological tissues. FRED toolkit does not rely on the water equivalent translation of tissues, but exploits the Computed Tomography anatomical information by reconstructing and simulating the atomic composition of each crossed tissue. FRED can be used as an efficient tool for dose recalculation, on the day of the treatment. In fact it can provide in about one minute on standard hardware the dose map obtained combining the treatment plan, earlier computed by the TPS, and the current patient anatomic arrangement
Free and Dissolved Gases in Castrocaro Spa Waters (Italy)
Free and dissolved gases in cold water samples from the Castrocaro spa, Northern Italy, were analyzed for their chemical composition. These gases were interpreted as the result of the binary mixing between a N2- and a CH4-rich component. CO2 is generally a minor constituent. N2/Ar ratios below the air typical value suggest that air saturated water (ASW) is the most likely source of atmospheric-derived components. This atmospheric end-member is predominant in low-salinity waters. Conversely, CH4-enriched gases are mainly associated with brackish to saline waters. The occurrence of minor amounts of light hydrocarbons (C2-C3) indicates a predominant biogenic origin of CH4. The He isotopic composition of the CH4-richest sample (3He/4He = 0.22 Ra) is in the range of values measured for cold seeps and mud volcanoes along the Northern Apennines foothills, and indicates a predominant crustal origin of this gas
Practical Approach to the Diagnosis of the Vulvo-Vaginal Stromal Tumors: An Overview
Background: The category of the "stromal tumors of the lower female genital tract" encompasses a wide spectrum of lesions with variable heterogeneity, which can be nosologically classified on the basis of their morphologic and immunohistochemical profiles as deep (aggressive) angiomyxoma (DAM), cellular angiofibroma (CAF), angiomyofibroblastoma (AMFB) or myofibroblastoma (MFB). Despite the differential diagnosis between these entities being usually straightforward, their increasingly recognized unusual morphological variants, along with the overlapping morphological and immunohistochemical features among these tumours, may raise serious differential diagnostic problems. Methods and Results: The data presented in the present paper have been retrieved from the entire published literature on the PubMed website about DAM, CAF, AFMB and MFB from 1984 to 2021. The selected articles are mainly represented by small-series, and, more rarely, single-case reports with unusual clinicopathologic features. The present review focuses on the diagnostic clues of the stromal tumours of the lower female genital tract to achieve a correct classification. The main clinicopathologic features of each single entity, emphasizing their differential diagnostic clues, are discussed and summarized in tables. Representative illustrations, including the unusual morphological variants, of each single tumour are also provided. Conclusion: Awareness by pathologists of the wide morphological and immunohistochemical spectrum exhibited by these tumours is crucial to achieve correct diagnoses and to avoid confusion with reactive conditions or other benign or malignant entities
Diphoton Signals for Large Extra Dimensions at the Tevatron and CERN LHC
We analyze the potentiality of hadron colliders to search for large extra dimensions via the production of photon pairs. The virtual exchange of Kaluza--Klein gravitons can significantly enhance this processes provided the quantum gravity scale () is in the TeV range. We studied in detail the subprocesses and taking into account the complete Standard Model and graviton contributions as well as the unitarity constraints. We show that the Tevatron Run II will be able to probe up to 1.5--1.9 TeV at 2 level, while the LHC can extend this search to 5.3--6.7 TeV, depending on the number of extra dimensions
Accelerating incoherent dedispersion
Incoherent dedispersion is a computationally intensive problem that appears
frequently in pulsar and transient astronomy. For current and future transient
pipelines, dedispersion can dominate the total execution time, meaning its
computational speed acts as a constraint on the quality and quantity of science
results. It is thus critical that the algorithm be able to take advantage of
trends in commodity computing hardware. With this goal in mind, we present
analysis of the 'direct', 'tree' and 'sub-band' dedispersion algorithms with
respect to their potential for efficient execution on modern graphics
processing units (GPUs). We find all three to be excellent candidates, and
proceed to describe implementations in C for CUDA using insight gained from the
analysis. Using recent CPU and GPU hardware, the transition to the GPU provides
a speed-up of 9x for the direct algorithm when compared to an optimised
quad-core CPU code. For realistic recent survey parameters, these speeds are
high enough that further optimisation is unnecessary to achieve real-time
processing. Where further speed-ups are desirable, we find that the tree and
sub-band algorithms are able to provide 3-7x better performance at the cost of
certain smearing, memory consumption and development time trade-offs. We finish
with a discussion of the implications of these results for future transient
surveys. Our GPU dedispersion code is publicly available as a C library at:
http://dedisp.googlecode.com/Comment: 15 pages, 4 figures, 2 tables, accepted for publication in MNRA
Low Energy Effective Action in N=2 Yang-Mills as an Integrated Anomaly
Based on chiral ring relations and anomalies, as described by Cachazo,
Douglas, Seiberg and Witten, we argue that the holomorphic effective action in
N=2 Yang-Mills theory can be understood as an integrated U(1) anomaly from a
purely field theory point of view. In particular, we show that the periods of
the Riemann surface arising from the generalized Konishi anomaly can be given a
physical interpretation without referring to special geometry. We also discuss
consequences for the multi-instanton calculus in N=2 Yang-Mills theory.Comment: 25 pages, 2 figures ; v2: reference adde
Gauge invariant formulation of Toda and KdV systems in extended superspace
We give a gauge invariant formulation of supersymmetric abelian Toda
field equations in \n2 superspace. Superconformal invariance is studied. The
conserved currents are shown to be associated with Drinfeld-Sokolov type
gauges. The extension to non-abelian \n2 Toda equations is discussed. Very
similar methods are then applied to a matrix formulation in \n2 superspace of
one of the \n2 KdV hierarchies.Comment: 21 page
A fast - Monte Carlo toolkit on GPU for treatment plan dose recalculation in proton therapy
In the context of the particle therapy a crucial role is played by Treatment Planning Systems (TPSs), tools aimed to compute and optimize the tratment plan. Nowadays one of the major issues related to the TPS in particle therapy is the large CPU time needed. We developed a software toolkit (FRED) for reducing dose recalculation time by exploiting Graphics Processing Units (GPU) hardware. Thanks to their high parallelization capability, GPUs significantly reduce the computation time, up to factor 100 respect to a standard CPU running software. The transport of proton beams in the patient is accurately described through Monte Carlo methods. Physical processes reproduced are: Multiple Coulomb Scattering, energy straggling and nuclear interactions of protons with the main nuclei composing the biological tissues. FRED toolkit does not rely on the water equivalent translation of tissues, but exploits the Computed Tomography anatomical information by reconstructing and simulating the atomic composition of each crossed tissue. FRED can be used as an efficient tool for dose recalculation, on the day of the treatment. In fact it can provide in about one minute on standard hardware the dose map obtained combining the treatment plan, earlier computed by the TPS, and the current patient anatomic arrangement
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The 20 February 2010 Madeira flash-floods: synoptic analysis and extreme rainfall assessment
This study aims to characterise the rainfall exceptionality and the meteorological context of the 20 February 2010 flash-floods in Madeira (Portugal). Daily and hourly precipitation records from the available rain-gauge station networks are evaluated in order to reconstitute the temporal evolution of the rainstorm, as its geographic incidence, contributing to understand the flash-flood dynamics and the type and spatial distribution of the associated impacts. The exceptionality of the rainstorm is further confirmed by the return period associated with the daily precipitation registered at the two long-term record stations, with 146.9 mm observed in the city of Funchal and 333.8 mm on the mountain top, corresponding to an estimated return period of approximately 290 yr and 90 yr, respectively. Furthermore, the synoptic associated situation responsible for the flash-floods is analysed using different sources of information, e.g., weather charts, reanalysis data, Meteosat images and radiosounding data, with the focus on two main issues: (1) the dynamical conditions that promoted such anomalous humidity availability over the Madeira region on 20 February 2010 and (2) the uplift mechanism that induced deep convection activity
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