The ALICE Silicon Pixel Detector Control system and online calibration tools

The ALICE Silicon Pixel Detector (SPD) contains nearly 107 hybrid pixel cells. The operation of the SPD requires online control and monitoring of some 2000 parameters and » 50000DACs. Information for each channel is stored in a configuration database. Timing and data management (» 6GB of raw data each calibration) are critical issues. An overview of the SPD electronics read out chain and of the detector control system is given with a detailed description of the front-end controls and the calibration strategy. The status of commissioning and a preliminary evaluation of detector performance are presented

Beam Test Performance and Simulation of Prototypes for the ALICE Silicon Pixel Detector

The silicon pixel detector (SPD) of the ALICE experiment in preparation at the Large Hadron Collider (LHC) at CERN is designed to provide the precise vertex reconstruction needed for measuring heavy flavor production in heavy ion collisions at very high energies and high multiplicity. The SPD forms the innermost part of the Inner Tracking System (ITS) which also includes silicon drift and silicon strip detectors. Single assembly prototypes of the ALICE SPD have been tested at the CERN SPS using high energy proton/pion beams in 2002 and 2003. We report on the experimental determination of the spatial precision. We also report on the first combined beam test with prototypes of the other ITS silicon detector technologies at the CERN SPS in November 2004. The issue of SPD simulation is briefly discussed.Comment: 4 pages, 5 figures, prepared for proceedings of 7th International Position Sensitive Detectors Conference, Liverpool, Sept. 200

The ALICE silicon pixel detector read-out electronics

The ALICE silicon pixel detector (SPD) constitutes the two innermost layers of the ALICE inner tracker system. The SPD contains 10 million pixels segmented in 120 detector modules (half staves), which are connected to the offdetector electronics with bidirectional optical links. Raw data from the on-detector electronics are sent to 20 FPGA-based processor cards (Routers) each carrying three 2-channel linkreceiver daughter-cards. The routers process the data and send them to the ALICE DAQ system via the ALICE detector data link (DDL). The SPD control, configuration and data monitoring is performed via the VME interface of the routers. This paper describes the detector readout and control via the off-detector electronics

Performance of ALICE pixel prototypes in high energy beams

The two innermost layers of the ALICE inner tracking system are instrumented with silicon pixel detectors. Single chip assembly prototypes of the ALICE pixels have been tested in high energy particle beams at the CERN SPS. Detection efficiency and spatial precision have been studied as a function of the threshold and the track incidence angle. The experimental method, data analysis and main results are presented.Comment: 10 pages, 9 figures, contribution to PIX2005 Workshop, Bonn (Germany), 5-8 September 200

Macrodispersion in generalized sub-Gaussian randomly heterogeneous porous media

In this work, we explore the implications of modeling the logarithm of hydraulic conductivity, Y , as a Generalized Sub-Gaussian (GSG) field on the features of conservative solute transport in randomly het-erogeneous, three-dimensional porous media. Hydro-geological properties are often viewed as Gaussian random fields. Nevertheless, the GSG model enables us to capture documented non-Gaussian traits that are not explained through classical Gaussian models. Our formulation yields lead-(or first-) order analytical solutions for key statistical moments of flow and transport variables. These include flow velocities, hydraulic head, and macrodispersion coefficients, as obtained across GSG log-conductivity fields. The analytical model is based on a first-order spectral theory, which constrains the rigorous validity of our results to small values of log-conductivity variance (sigma(2)(Y) << 1 ). Analytical results are then compared against detailed numerical estimates obtained through a Monte Carlo scheme encompassing various levels of domain heterogeneity. An asymptotic Fickian transport regime is attained at late times in both Gaussian and GSG Y fields. Convergence to such regime is slower for GSG as compared to Gaussian fields. This suggests a strong impact of the heterogeneity structure on non-Fickian pre-asymptotic behaviors of the kind documented in the literature. The quality of the comparison between analytical and numerical results deteriorates with increasing sigma(2)(Y) . Otherwise, our lead-order solutions frame macrodispersion coefficients in appropriate orders of magnitude also for values of sigma(2)(Y) up to approximately 1.7, which are consistent with the spatial variability of Y across a single geological unit. In this sense, our analytical approach enables one to obtain prior information on solute plume evolution and to grasp the effects of non-Gaussian medium heterogeneity while favoring simplicity. Our findings also enhance the current level of under-standing of the nature of mass transfer across heterogeneous media characterized by complex variability structures which cannot be reconciled with classical Gaussian scenarios. (C) 2022 Elsevier Ltd. All rights reserved

Simulación de programas paralelos en Haskell

El estudio de formas de incorporar de manera simple y eficiente la programación paralela al desarrollo de software sigue siendo objeto de investigación. En particular, en el lenguaje de programación Haskell (Marlow 2010) se ha desarrollado una variedad de extensiones del lenguaje, bibliotecas, y abstracciones, que permiten encarar el problema de la programación paralela desde diversos ángulos. Para dar soporte a la experimentación con formas nuevas de incorporar paralelismo al desarrollo de software es necesario el desarrollo de herramientas adecuadas que permitan el análisis de las ejecuciones obtenidas. En este trabajo se propone una herramienta para el estudio de programas paralelos dentro del lenguaje de programación Haskell. Esta herramienta permite al programador observar directamente qué computaciones se van a paralelizar, dándole un mayor entendimiento sobre la ejecución de su programa.Trabajos finalesSociedad Argentina de Informática e Investigación Operativa (SADIO

Global sensitivity analysis of mass transfer and reaction dynamics for electrokinetic transport in porous media

Electrokinetic (EK) technologies are promising solutions for the remediation of contaminated sites, particularly in low-permeability porous media. However, their widespread adoption is hindered by the challenge of predicting the complex, coupled physico-chemical processes triggered by the application of external electric fields in the subsurface. Numerical models therefore represent essential tools to interpret system behavior. Uncertainties in experimental data, as well as in the formulation of conceptual models, still pose a challenge to develop robust predictive tools. In this context, our work addresses the impact of various sources of uncertainty on model-based predictions of EK transport in porous media. We employ Monte Carlo-based global sensitivity analyses (GSA) within both single-model (SM-GSA) and multi-model (MM-GSA). The multi-model approach relies on a theoretical framework encompassing different models capable of interpreting a set of EK transport scenarios. This allows us to address the impact of model formulation besides parametric uncertainty on mass transfer and reaction dynamics of EK transport. All candidate models in our set are based on a 2D dipole electrode configuration and each model incorporates a different combination of physico-chemical processes to explore different EK remediation scenarios dominated by electromigration or electroosmosis, for both conservative and reactive transport settings. We also investigate the influence of background electrolytes, charge interactions, reactant mobility and degradation reaction kinetics on system dynamics. To overcome the computational burden of process-based modeling and GSA implementations, we develop machine learning-based surrogate models. The latter are employed within both SM- and MM-GSA frameworks, using Sobol’ and AMAE sensitivity indices, respectively. This work provides a comprehensive quantification of how multiple sources of uncertainty impact electrokinetic transport behavior in porous media

Examining the effects of sodium ions on the binding of antagonists to dopamine D2 and D3 receptors

Many G protein-coupled receptors have been shown to be sensitive to the presence of sodium ions (Na+). Using radioligand competition binding assays, we have examined and compared the effects of sodium ions on the binding affinities of a number of structurally diverse ligands at human dopamine D2 and dopamine D3 receptor subtypes, which are important therapeutic targets for the treatment of psychotic disorders. At both receptors, the binding affinities of the antagonists/inverse agonists SB-277011-A, L,741,626, GR 103691 and U 99194 were higher in the presence of sodium ions compared to those measured in the presence of the organic cation, N-methyl-D-glucamine, used to control for ionic strength. Conversely, the affinities of spiperone and (+)-butaclamol were unaffected by the presence of sodium ions. Interestingly, the binding of the antagonist/inverse agonist clozapine was affected by changes in ionic strength of the buffer used rather than the presence of specific cations. Similar sensitivities to sodium ions were seen at both receptors, suggesting parallel effects of sodium ion interactions on receptor conformation. However, no clear correlation between ligand characteristics, such as subtype selectivity, and sodium ion sensitivity were observed. Therefore, the properties which determine this sensitivity remain unclear. However these findings do highlight the importance of careful consideration of assay buffer composition for in vitro assays and when comparing data from different studies, and may indicate a further level of control for ligand binding in vivo

The ALICE Silicon Pixel Detector System (SPD)

The ALICE silicon pixel detector (SPD) comprises the two innermost layers of the ALICE inner tracker system. The SPD includes 120 detector modules (half-staves) each consisting of 10 ALICE pixel chips bump bonded to two silicon sensors and one multi-chip read-out module. Each pixel chip contains 8192 active cells, so that the total number of pixel cells in the SPD is ≈ 107. The on-detector read-out is based on a multi-chip-module containing 4 ASICs and an optical transceiver module. The constraints on material budget and detector module dimensions are very demanding

In-stent restenosis of superficial femoral artery: use all arrows in the quiver.

In-stent restenosis (ISR) is a common superficial femoral artery (SFA) stenting complication, occurring in more than one third of patients within 2-3 years after the index procedure. Moreover, there is no standard treatment for ISR, and although many options are available, there is still limited data regarding its optimal management. We report a paradigmatic case report of a patient complaining of symptomatic peripheral arterial disease, underwent multiple endovascular revascularizations for recurrent femoro-popliteal ISR. A step-by-step approach was followed. At the time of the first presentation, the ISR was treated by drug-eluting balloon (DEB) angioplasty. The repeated ISR was treated by laser debulking, achieving a good angiographic result. Finally, after the third repeated restenosis, a combined approach with laser debulking and DEB angioplasty guaranteed a good acute angiographic result. Long-term duplex-scan follow-up demonstrated the good patency of the femoro-popliteal target lesion