1,729 research outputs found

    Nuclear re-interaction effects in quasi-elastic neutrino nucleus scattering

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    The quasi-elastic neutrino-nucleus cross section has been calculated by using a Fermi gas model corrected to consider the re-scattering between the emitted nucleon and the rest nucleus. As an example of the relevance of this effect we show results for the muon production cross section on 16O target.Comment: 7 pages, 4 Postscript figures, Contribution to NuInt01 Workshop, KEK, Tsukuba, Japa

    Extreme-Point-based Heuristics for the Three-Dimensional Bin Packing problem

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    One of the main issues in addressing three-dimensional packing problems is finding an efficient and accurate definition of the points at which to place the items inside the bins, because the performance of exact and heuristic solution methods is actually strongly influenced by the choice of a placement rule. We introduce the extreme point concept and present a new extreme point-based rule for packing items inside a three-dimensional container. The extreme point rule is independent from the particular packing problem addressed and can handle additional constraints, such as fixing the position of the items. The new extreme point rule is also used to derive new constructive heuristics for the three-dimensional bin-packing problem. Extensive computational results show the effectiveness of the new heuristics compared to state-of-the-art results. Moreover, the same heuristics, when applied to the two-dimensional bin-packing problem, outperform those specifically designed for the proble

    Identification of Showers with Cores Outside the ARGO-YBJ Detector

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    In any EAS array, the rejection of events with shower cores outside the detector boundaries is of great importance. A large difference between the true and the reconstructed shower core positions may lead to a systematic miscalculation of some shower characteristics. Moreover, an accurate determination of the shower core position for selected internal events is important to reconstruct the primary direction using conical fits to the shower front, improving the detector angular resolution, or to performe an efficient gamma/hadron discrimination. In this paper we present a procedure able to identify and reject showers with cores outside the ARGO-YBJ carpet boundaries. A comparison of the results for gamma and proton induced showers is reported.Comment: 4 pages, to be published in the Proceedings of the 28th International Cosmic Ray Conference (Tsukuba, Japan 2003

    Expected sensitivity of ARGO-YBJ to detect point gamma-ray sources

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    ARGO-YBJ is a full coverage air shower detector currently under construction at the Yangbajing Laboratory (4300 m a.s.l., Tibet, China). First data obtained with a subset of the apparatus will be available in summer 2003 while the full detector operation is expected in 2005. One of the main aims of ARGO-YBJ is the observation of gamma-ray sources, at an energy threshold of a few hundreds GeV. In this paper we present the expected sensitivity to detect point gamma ray sources, with particular attention to the Crab Nebula. According to our simulations a Crab-like signal could be detected in one year of operation with a statistical significance of 10 standard deviations, without any gamma/hadron discrimination.Comment: 4 pages, 2 Postscript figure

    Identification of the missing pluripotency mediator downstream of leukaemia inhibitory factor

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    Self-renewal of pluripotent mouse embryonic stem (ES) cells is sustained by the cytokine leukaemia inhibitory factor (LIF) acting through the transcription factor Stat3. Several targets of Stat3 have previously been identified, most notably the reprogramming factor Klf4. However, such factors are neither required nor sufficient for the potent effect of LIF. We took advantage of Stat3 null ES cells to confirm that Stat3 mediates the self-renewal response to LIF. Through comparative transcriptome analysis intersected with genome location data, we arrived at a set of candidate transcription factor effectors. Among these, Tfcp2l1 (also known as Crtr-1) was most abundant. Constitutive expression of Tfcp2l1 at levels similar to those induced by LIF effectively substituted for LIF or Stat3 in sustaining clonal self-renewal and pluripotency. Conversely, knockdown of Tfcp2l1 profoundly compromised responsiveness to LIF. We further found that Tfcp2l1 is both necessary and sufficient to direct molecular reprogramming of post-implantation epiblast stem cells to naĂŻve pluripotency. These results establish Tfcp2l1 as the principal bridge between LIF/Stat3 input and the transcription factor core of naĂŻve pluripotency

    A robust enhancement to the Clarke-Wright savings algorithm

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    We address the Clarke and Wright (CW) savings algorithm proposed for the Capacitated Vehicle Routing Problem (CVRP). We first consider a recent enhancement which uses the put first larger items idea originally proposed for the bin packing problem and show that the conflicting idea of putting smaller items first has a comparable performance. Next, we propose a robust enhancement to the CW savings formulation. The proposed formulation is normalized to efficiently solve different problems, independent from the measurement units and parameter intervals. To test the performance of the proposed savings function, we conduct an extensive computational study on a large set of well-known instances from the literature. Our results show that the proposed savings function provides shorter distances in the majority of the instances and the average performance is significantly better than previously presented enhancements

    Implementing A Balanced Scorecard In A Not-For-Profit Organization

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    This paper examines the use of the Balanced Scorecard in a not-for-profit organization (Cattaraugus County ReHabilitation Center).  The ReHabilitation Center has begun using the Balanced Scorecard paradigm in its strategic planning process.  In this paper an overview is presented of the basic concepts of the Balanced Scorecard including the financial perspective, customer perspective, internal process perspective, and learning and growth perspective.  The history and services of the ReHabilitation Center are then summarized.  The application of the Balanced Scorecard approach to the ReHabilitation Center is discussed in detail.  Implications in using the Balanced Scorecard are discussed.  Finally, conclusions regarding the use of the Balanced Scorecard in a not-for-profit organization are presented

    Implementing A Balanced Scorecard In A Not-For-Profit Organization

    Get PDF
    This paper examines the use of the Balanced Scorecard in a not-for-profit organization (Cattaraugus County ReHabilitation Center).  The ReHabilitation Center has begun using the Balanced Scorecard paradigm in its strategic planning process.  In this paper an overview is presented of the basic concepts of the Balanced Scorecard including the financial perspective, customer perspective, internal process perspective, and learning and growth perspective.  The history and services of the ReHabilitation Center are then summarized.  The application of the Balanced Scorecard approach to the ReHabilitation Center is discussed in detail.  Implications in using the Balanced Scorecard are discussed.  Finally, conclusions regarding the use of the Balanced Scorecard in a not-for-profit organization are presented

    The Networked Common Goods Game

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    We introduce a new class of games called the networked common goods game (NCGG), which generalizes the well-known common goods game. We focus on a fairly general subclass of the game where each agent's utility functions are the same across all goods the agent is entitled to and satisfy certain natural properties (diminishing return and smoothness). We give a comprehensive set of technical results listed as follows. * We show the optimization problem faced by a single agent can be solved efficiently in this subclass. The discrete version of the problem is however NP-hard but admits an fully polynomial time approximation scheme (FPTAS). * We show uniqueness results of pure strategy Nash equilibrium of NCGG, and that the equilibrium is fully characterized by the structure of the network and independent of the choices and combinations of agent utility functions. * We show NCGG is a potential game, and give an implementation of best/better response Nash dynamics that lead to fast convergence to an Ï”\epsilon-approximate pure strategy Nash equilibrium. * Lastly, we show the price of anarchy of NCGG can be as large as Ω(n1−ϔ)\Omega(n^{1-\epsilon}) (for any Ï”>0\epsilon>0), which means selfish behavior in NCGG can lead to extremely inefficient social outcomes
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