2,997 research outputs found
Equivalence between local Fermi gas and shell models in inclusive muon capture from nuclei
Motivated by recent studies of inclusive neutrino nucleus processes and muon
capture within a correlated local Fermi gas model (LFG), we discuss the
relevance of nuclear finite size effects in these reactions at low energy, in
particular for muon capture. To disentangle these effects from others coming
from the reaction dynamics we employ here a simple uncorrelated shell model
that embodies the typical finite size content of the problem. The integrated
decay widths of muon atoms calculated with this shell model are then compared
for several nuclei with those obtained within the uncorrelated LFG, using in
both models exactly the same theoretical ingredients and parameters. We find
that the two predictions are in quite good agreement, within 1--7%, when the
shell model density and the correct energy balance is used as input in the LFG
calculation. The present study indicates that, despite the low excitation
energies involved in the reaction, integrated inclusive observables, like the
total muon capture width, are quite independent of the fine details of the
nuclear wave functions.Comment: 11 pages, 8 figures. Final version to be published in EPJ
Local Fermi gas in inclusive muon capture from nuclei
We compare local Fermi gas and shell model in muon capture in nuclei in order
to estimate the effect of finite nuclear size in low energy weak reactions.Comment: 6 pages, 8 figures. To be published in the Proceedings of 20th Max
Born Symposium, Wroclaw (Poland), December 7-10, 200
A resource allocation mechanism based on cost function synthesis in complex systems
While the management of resources in computer systems can greatly impact the usefulness and integrity of the system, finding an optimal solution to the management problem is unfortunately NP hard. Adding to the complexity, today\u27s \u27modern\u27 systems - such as in multimedia, medical, and military systems - may be, and often are, comprised of interacting real and non-real-time components. In addition, these systems can be driven by a host of non-functional objectives – often differing not only in nature, importance, and form, but also in dimensional units and range, and themselves interacting in complex ways. We refer to systems exhibiting such characteristics as Complex Systems (CS).
We present a method for handling the multiple non-functional system objectives in CS, by addressing decomposition, quantification, and evaluation issues. Our method will result in better allocations, improve objective satisfaction, improve the overall performance of the system, and reduce cost -in a global sense. Moreover, we consider the problem of formulating the cost of an allocation driven by system objectives. We start by discussing issues and relationships among global objectives, their decomposition, and cost functions for evaluation of system objective. Then, as an example of objective and cost function development, we introduce the concept of deadline balancing. Next, we proceed by proving the existence of combining models and their underlying conditions. Then, we describe a hierarchical model for system objective function synthesis. This synthesis is performed solely for the purpose of measuring the level of objective satisfaction in a proposed hardware to software allocation, not for design of individual software modules. Then, Examples are given to show how the model applies to actual multi-objective problems.
In addition the concept of deadline balancing is extended to a new scheduling concept, namely Inter-Completion-Time Scheduling (ICTS. Finally, experiments based on simulation have been conducted to capture various properties of the synthesis approach as well as ICTS. A prototype implementation of the cost functions synthesis and evaluation environment is described, highlighting the applicability and usefulness of the synthesis in realistic applications
EmergencyGrid:Planning in Convergence Environments
Government agencies are often responsible for event handling, planning, coordination, and status reporting during emergency response in natural disaster events such as floods, tsunamis and earthquakes. Across such a range of emergency response scenarios, there is a common set of requirements that distributed intelligent computer systems generally address. To support the implementation of these requirements, some researchers are proposing the creation of grids, where final interface and processing nodes perform joint work supported by a network infrastructure. The aim of this project is to extend the concepts of emergency response grids, using a convergence scenario between web and other computational platforms. Our initial work focuses on the Interactive Digital TV platform, where we intend to transform individual TV devices into active final nodes, using a hierarchical planning structure. We describe the architecture of this approach and an initial prototype specification that is being developed to validate some concepts and illustrate the advantages of this convergence planning environment
A study of the structure of jet turbulence producing jet noise
Characteristics of turbulent structure of mixing region near outlet of circular subsonic jet and production of jet nois
Primary Systemic Vasculitis in Childhood
As vasculites sistémicas constituem um grupo de doenças, pouco frequentes na infância, caracterizadas por inflamação e necrose vascular. A sua tradução clínica é heterogénea, condicionada pelo tipo de vaso e orgão afectados. Recentemente foi proposta uma classificação das vasculites em idade pediátrica, que tem em conta a dimensão dos vasos envolvidos, sendo também validados critérios de diagnóstico para os tipos mais frequentes em crianças. A presente revisão tem como objectivo abordar os tipos mais frequentes de vasculites na infância, suas manifestações clínicas, diagnóstico e terapêutica
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