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Search Results: 1 - 10 of 200629 matches for " P. Mosteiro "
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A. Fluka Study of Underground Cosmogenic Neutron Production
A Empl,E. V. Hungerford,R. Jasim,P. Mosteiro
Physics , 2014, DOI: 10.1088/1475-7516/2014/08/064
Abstract: Neutrons produced by cosmic muon interactions are important contributors to backgrounds in underground detectors when searching for rare events. Typically such neutrons can dominate the background, as they are particularly difficult to shield and detect. Since actual data is sparse and not well documented, simulation studies must be used to design shields and predict background rates. Thus validation of any simulation code is necessary to assure reliable results. This work compares in detail the predictions of the FLUKA simulation code to existing data, and uses this code to report a simulation of cosmogenic backgrounds for typical detectors embedded in a water tank with liquid scintillator shielding.
Study of Cosmogenic Neutron Backgrounds at LNGS
A. Empl,R. Jasim,E. Hungerford,P. Mosteiro
Physics , 2012,
Abstract: Cosmic muon interactions are important contributors to backgrounds in underground detectors when searching for rare events. Typically neutrons dominate this background as they are particularly difficult to shield and detect in a veto system. Since actual background data is sparse and not well documented, simulation studies must be used to design shields and predict background rates. This means that validation of any simulation code is necessary to assure reliable results. This work studies the validation of the FLUKA simulation code, and reports the results of a simulation of cosmogenic background for a liquid argon two-phase detector embedded within a water tank and liquid scintillator shielding.
A Faster Counting Protocol for Anonymous Dynamic Networks
Alessia Milani,Miguel A. Mosteiro
Computer Science , 2015,
Abstract: We study the problem of counting the number of nodes in a slotted-time communication network, under the challenging assumption that nodes do not have identifiers and the network topology changes frequently. That is, for each time slot links among nodes can change arbitrarily provided that the network is always connected. Tolerating dynamic topologies is crucial in face of mobility and unreliable communication whereas, even if identifiers are available, it might be convenient to ignore them in massive networks with changing topology. Counting is a fundamental task in distributed computing since knowing the size of the system often facilitates the design of solutions for more complex problems. Currently, the best upper bound proved on the running time to compute the exact network size is double-exponential. However, only linear complexity lower bounds are known, leaving open the question of whether efficient Counting protocols for Anonymous Dynamic Networks exist or not. In this paper we make a significant step towards answering this question by presenting a distributed Counting protocol for Anonymous Dynamic Networks which has exponential time complexity. Our algorithm ensures that eventually every node knows the exact size of the system and stops executing the algorithm. Previous Counting protocols have either double-exponential time complexity, or they are exponential but do not terminate, or terminate but do not provide running-time guarantees, or guarantee only an exponential upper bound on the network size. Other protocols are heuristic and do not guarantee the correct count.
Hiponatremia secundaria a diuréticos
Las Heras Mosteiro,J.; Taboada Taboada,M.;
Medifam , 2001, DOI: 10.4321/S1131-57682001000500008
Abstract: the most important cause of hyponatremia in adults is diuretic′s therapy. effective use of diuretics by the family doctor, requires knowledge of the pharmacology of each diuretic agent coupled with an understanding of pathophysiology of the patient′s disease. we report a case of 70-years old female who had heart failure class iii-iv new york heart association (nyha) secondary to multivalvular cardiomyopathy. she had implanted vvi medtronic pacemaker for sick-sinus syndrome. treatment with furosemide, spironolactone, enalapril, digoxine and oral anticoagulant. she presented a clinical pattern of disorientation and a swich-off episode with severe hyponatremia.
Momento y lugar: reflexiones sobre el extra amiento de monumentos
Javier García-Gutierrez Mosteiro
Cuadernos de Proyectos Arquitectónicos , 2012,
Abstract: Resumen El artículo que se propone plantea –a partir de otros estudios ya desarrollados por el autor– distintas reflexiones acerca del lugar en la consideración del valor monumental, con especial atención al objeto arquitectónico. El compromiso del monumento con el lugar, firmemente establecido desde las construcciones megalíticas, ha conocido a lo largo de la historia significativas alteraciones. En torno a éstas desde el traslado de los obeliscos egipcios hasta el desmantelamiento y reconstrucción, en otro entorno, de edificios completos‐ se trata en este estudio; se parte de la consideración de la salvaguarda de determinados valores patrimoniales y se atiende a los criterios de intervención habidos en cada caso (cubriendo actuaciones representativas ‐desde la Antigüedad a las más propias de nuestros días‐. Palabras clave valor, monumento, lugar, patrimonio, intervención Abstract Based on other studies already carried out by the author, this article presents different reflections about the concept of place with regards to monumental value, with special attention to the architectural object. The commitment of a monument with its site, firmly established from the time of megalithic constructions, has suffered significant alterations through history. This article deals with these alterations, from the transfer of Egyptian obelisks to other places to the disassembly and reconstruction of entire buildings within a different context. The safeguarding of certain values of our architectural heritage is an important concept, and attention is paid to the different action criteria found in each specific case ‐covering representative interventions, from antiquity to those closer to our present time‐. Key words value, monument, place, heritage, intervention
First Commissioning of a Cryogenic Distillation Column for Low Radioactivity Underground Argon
H. O. Back,T. Alexander,A. Alton,C. Condon,E. de Haas,C. Galbiati,A. Goretti,T. Hohmann,An. Ianni,C. Kendziora,B. Loer,D. Montanari,P. Mosteiro,S. Pordes
Physics , 2012,
Abstract: We report on the performance and commissioning of a cryogenic distillation column for low radioactivity underground argon at Fermi National Accelerator Laboratory. The distillation column is designed to accept a mixture of argon, helium, and nitrogen and return pure argon with a nitrogen contamination less than 10 ppm. In the first commissioning, we were able to run the distillation column in a continuous mode and produce argon that is 99.9% pure. After running in a batch mode, the argon purity was increased to 99.95%, with 500 ppm of nitrogen remaining. The efficiency of collecting the argon from the gas mixture was between 70% and 81%, at an argon production rate of 0.84-0.98 kg/day.
A Highly Efficient Neutron Veto for Dark Matter Experiments
Alex Wright,Pablo Mosteiro,Ben Loer,Frank Calaprice
Physics , 2010, DOI: 10.1016/j.nima.2011.04.009
Abstract: We present a conceptual design for an active neutron veto, based on boron-loaded liquid scintillator, for use in direct-detection dark matter experiments. The simulated efficiency of a 1 meter thick veto, after including the effects of neutron captures in the inner detector and inefficiencies due to feed-throughs into the veto, is greater than 99.5% for background events produced by radiogenic neutrons, while the background due to externally produced cosmogenic neutrons is reduced by more than 95%. The ability of the veto to both significantly suppress, and provide in situ measurements of, these two dominant sources of background would make the next generation of dark matter experiments much more robust, and dramatically improve the credibility of a dark matter detection claim based on the observation of a few recoil events. The veto would also allow direct extrapolation between the background-free operation of a small detector and the physics reach of a larger detector of similar construction.
Dynamic Multiple-Message Broadcast: Bounding Throughput in the Affectance Model
Dariusz R. Kowalski,Miguel A. Mosteiro,Kevin Zaki
Computer Science , 2015,
Abstract: We study a dynamic version of the Multiple-Message Broadcast problem, where packets are continuously injected in network nodes for dissemination throughout the network. Our performance metric is the ratio of the throughput of such protocol against the optimal one, for any sufficiently long period of time since startup. We present and analyze a dynamic Multiple-Message Broadcast protocol that works under an affectance model, which parameterizes the interference that other nodes introduce in the communication between a given pair of nodes. As an algorithmic tool, we develop an efficient algorithm to schedule a broadcast along a BFS tree under the affectance model. To provide a rigorous and accurate analysis, we define two novel network characteristics based on the network topology and the affectance function. The combination of these characteristics influence the performance of broadcasting with affectance (modulo a logarithmic function). We also carry out simulations of our protocol under affectance. To the best of our knowledge, this is the first dynamic Multiple-Message Broadcast protocol that provides throughput guarantees for continuous injection of messages and works under the affectance model.
Insertion Sort is O(n log n)
Michael A. Bender,Martin Farach-Colton,Miguel Mosteiro
Computer Science , 2004,
Abstract: Traditional Insertion Sort runs in O(n^2) time because each insertion takes O(n) time. When people run Insertion Sort in the physical world, they leave gaps between items to accelerate insertions. Gaps help in computers as well. This paper shows that Gapped Insertion Sort has insertion times of O(log n) with high probability, yielding a total running time of O(n log n) with high probability.
Algorithmic Mechanisms for Reliable Internet-based Computing under Collusion
Antonio Fernandez Anta,Chryssis Georgiou,Miguel A. Mosteiro
Computer Science , 2013,
Abstract: In this work, using a game-theoretic approach, cost-sensitive mechanisms that lead to reliable Internet-based computing are designed. In particular, we consider Internet-based master-worker computations, where a master processor assigns, across the Internet, a computational task to a set of potentially untrusted worker processors and collects their responses. Workers may collude in order to increase their benefit. Several game-theoretic models that capture the nature of the problem are analyzed, and algorithmic mechanisms that, for each given set of cost and system parameters, achieve high reliability are designed. Additionally, two specific realistic system scenarios are studied. These scenarios are a system of volunteer computing like SETI, and a company that buys computing cycles from Internet computers and sells them to its customers in the form of a task- computation service. Notably, under certain conditions, non redundant allocation yields the best trade-off between cost and reliability.
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