9,484 research outputs found

    Effective Actions for Heterotic M-Theory

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    We discuss the moduli space approximation for heterotic M-theory, both for the minimal case of two boundary branes only, and when a bulk brane is included. The resulting effective actions may be used to describe the cosmological dynamics in the regime where the branes are moving slowly, away from singularities. We make use of the recently derived colliding branes solution to determine the global structure of moduli space, finding a boundary at which the trajectories undergo a hard wall reflection. This has important consequences for the allowed moduli space trajectories, and for the behaviour of cosmological perturbations in the model.Comment: 21 pages, 4 figures. References added and some discussions clarifie

    Flavor structure with multi moduli in 5D supergravity

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    We study 5-dimensional supergravity on S^1/Z_2 with a physical Z_2-odd vector multiplet, which yields an additional modulus other than the radion. We derive 4-dimensional effective theory and find additional terms in the Kahler potential that are peculiar to the multi moduli case. Such terms can avoid tachyonic soft scalar masses at tree-level, which are problematic in the single modulus case. We also show that the flavor structure of the soft terms are different from that in the single modulus case when hierarchical Yukawa couplings are generated by wavefunction localization in the fifth dimension. We present a concrete model that stabilizes the moduli at a supersymmetry breaking Minkowski minimum, and show the low energy sparticle spectrum.Comment: 30 pages, 2 figures; version to be published in PR

    Corrections to the Boltzmann mean free path in disordered systems with finite size scatterers

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    The mean free path is an essential characteristic length in disordered systems. In microscopic calculations, it is usually approximated by the classical value of the elastic mean free path. It corresponds to the Boltzmann mean free path when only isotropic scattering is considered, but it is different for anisotropic scattering. In this paper, we work out the corrections to the so called Boltzmann mean free path due to multiple scattering effects on finite size scatterers, in the s-wave approximation, ie. when the elastic mean free path is equivalent to the Boltzmann mean free path. The main result is the expression for the mean free path expanded in powers of the perturbative parameter given by the scatterer density.Comment: 12 page

    New sufficient conditions to ulam stabilities for a class of higher order integro-differential equations

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    In this work, we present sufficient conditions in order to establish different types of Ulam stabilities for a class of higher order integro-differential equations. In particular, we consider a new kind of stability, the sigma-semi-Hyers-Ulam stability, which is in some sense between the Hyers-Ulam and the Hyers-Ulam-Rassias stabilities. These new sufficient conditions result from the application of the Banach Fixed Point Theorem, and by applying a specific generalization of the Bielecki metric.publishe

    Stochastic Optimization for Network-Constrained Power System Scheduling Problem

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    The stochastic nature of demand and wind generation has a considerable effect on solving the scheduling problem of a modern power system. Network constraints such as power flow equations and transmission capacities also need to be considered for a comprehensive approach to model renewable energy integration and analyze generation system flexibility. Firstly, this paper accounts for the stochastic inputs in such a way that the uncertainties are modeled as normally distributed forecast errors. The forecast errors are then superimposed on the outputs of load and wind forecasting tools. Secondly, it efficiently models the network constraints and tests an iterative algorithm and a piecewise linear approximation for representing transmission losses in mixed integer linear programming (MILP). It also integrates load shedding according to priority factors set by the system operator. Moreover, the different interactions among stochastic programming, network constraints, and prioritized load shedding are thoroughly investigated in the paper. The stochastic model is tested on a power system adopted from Jeju Island, South Korea. Results demonstrate the impact of wind speed variability and network constraints on the flexibility of the generation system. Further analysis shows the effect of loss modeling approaches on total cost, accuracy, computational time, and memory requirement

    Produção de mudas frutíferas no Nordeste.

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    Objetivando conhecer a situacao da producao de mudas no contexto da fruticultura nordestina, a Embrapa Agroindustria Tropical, realizou um levantamento nos estados de Sergipe, Alagoas,Pernambuco, Paraiba, Rio Grande do Norte, Ceara, Piaui e Maranhao.bitstream/CNPAT-2010/5359/1/Ct-027.pd

    Making robot’s attitudes predictable: a stereotype content model for human-robot interaction in groups

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    Stereotypes play a key role both in human and in robot perception. As such, these may play an important role in predicting behavior towards the targets of said stereotypes. In this paper, we argue for the usefulness of exploring how stable dimensions of stereotype content, more specific?ally warmth and competence, apply to HRI. We propose to do so by examining the impact of these characteristics, displayed by robots, on the emotions, behaviors and future intention of participants to interact and work with robots. We chose these two stereotypical dimensions given that research has demonstrated their underlying and ubiquitous influence on people perception and responses. Moreover, we decided to explore this issue in the context of small group interactions due to the ever-common nature of this type of social arrangements in people’s everyday life.info:eu-repo/semantics/acceptedVersio

    Small bowel obstruction due to intraluminal metastasis from malignant melanoma

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    The most common form of presentation of malignant melanoma is cutaneous. However, it is important to notice that it can occur in any part of the body, mostly from metastatic route. Gastrointestinal forms of symptomatic metastasis are rare, making it sometimes difficult to diagnose. We present a rare case of an 84-year-old female with a small bowel obstruction due to melanoma metastasis. She was treated with an enterectomy, with no surgical or post-operative complications. Although surgery should be reserved from symptomatic patients, some authors refer to it as a palliative treatment with improvement in long-term survival.info:eu-repo/semantics/publishedVersio
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