442 research outputs found

    Limitation of energy deposition in classical N body dynamics

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    Energy transfers in collisions between classical clusters are studied with Classical N Body Dynamics calculations for different entrance channels. It is shown that the energy per particle transferred to thermalised classical clusters does not exceed the energy of the least bound particle in the cluster in its ``ground state''. This limitation is observed during the whole time of the collision, except for the heaviest system.Comment: 13 pages, 15 figures, 1 tabl

    Chapter 14 - Regional development and cooperation

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    This chapter provides an assessment of knowledge and practice on regional development and cooperation to achieve climate change mitigation. It will examine the regional trends and dimensions of the mitigation challenge. It will also analyze what role regional initiatives, both with a focus on climate change and in other domains such as trade, can play in addressing these mitigation challenges. The regional dimension of mitigation was not explicitly addressed in the IPCC Fourth Assessment Report (AR4). Its discussion of policies, instruments, and cooperative agreements (Working Group III AR4, Chapter 13) was focused primarily on the global and national level. However, mitigation challenges and opportunities differ significantly by region. This is particularly the case for the interaction between development / growth opportunities and mitigation policies, which are closely linked to resource endowments, the level of economic development, patterns of urbanization and industrialization, access to finance and technology, and - more broadly - the capacity to develop and implement various mitigation options. There are also modes of regional cooperation, ranging from regional initiatives focused specifically on climate change (such as the emissions trading scheme (ETS) of the European Union (EU)) to other forms of cooperation in the areas of trade, energy, or infrastructure, that could potentially provide a platform for delivering and implementing mitigation policies. These dimensions will be examined in this chapter. Specifically, this chapter will address the following questions: - Why is the regional level important for analyzing and achieving mitigation objectives? - What are the trends, challenges, and policy options for mitigation in different regions? - To what extent are there promising opportunities, existing examples, and barriers for leapfrogging in technologies and development strategies to low-carbon development paths for different regions? - What are the interlinkages between mitigation and adaptation at the regional level? - To what extent can regional initiatives and regional integration and cooperation promote an agenda of low-carbon climate-resilient development? What has been the record of such initiatives, and what are the barriers? Can they serve as a platform for further mitigation activities

    Max-Margin Dictionary Learning for Multiclass Image Categorization

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    Abstract. Visual dictionary learning and base (binary) classifier train-ing are two basic problems for the recently most popular image cate-gorization framework, which is based on the bag-of-visual-terms (BOV) models and multiclass SVM classifiers. In this paper, we study new algo-rithms to improve performance of this framework from these two aspects. Typically SVM classifiers are trained with dictionaries fixed, and as a re-sult the traditional loss function can only be minimized with respect to hyperplane parameters (w and b). We propose a novel loss function for a binary classifier, which links the hinge-loss term with dictionary learning. By doing so, we can further optimize the loss function with respect to the dictionary parameters. Thus, this framework is able to further increase margins of binary classifiers, and consequently decrease the error bound of the aggregated classifier. On two benchmark dataset

    Random walks in space time mixing environments

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    We prove that random walks in random environments, that are exponentially mixing in space and time, are almost surely diffusive, in the sense that their scaling limit is given by the Wiener measure.Comment: 28 page

    P2Y1 receptor modulation of endogenous ion channel function in Xenopus oocytes: Involvement of transmembrane domains

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    Agonist activation of the hP2Y1 receptor expressed in Xenopus oocytes stimulated an endogenous voltage-gated ion channel, previously identified as the transient inward (Tin) channel. When human P2Y1 (hP2Y1) and skate P2Y (sP2Y) receptors were expressed in Xenopus oocytes, time-to-peak values (a measure of the response to membrane hyperpolarization) of the Tin channel were significantly reduced compared to oocytes expressing the hB1-bradykinin receptor or the rat M1-muscarinic (rM1) receptor. Differences in activation were also observed in the Tin currents elicited by various P2Y receptor subtypes. The time-to-peak values of the Tin channel in oocytes expressing the hP2Y4, hP2Y11, or hB1-bradykinin receptors were similar, whereas the channel had significantly shorter time-to-peak values in oocytes expressing either the hP2Y1 or sP2Y receptor. Amino acid substitutions at His-132, located in the third transmembrane domain (TM3) of the hP2Y1 receptor, delayed the onset of channel opening, but not the kinetics of the activation process. In addition, Zn2+ sensitivity was also dependent on the subtype of P2Y receptor expressed. Replacement of His-132 in the hP2Y1 receptor with either Ala or Phe increased Zn2+ sensitivity of the Tin current. In contrast, truncation of the C-terminal region of the hP2Y1 receptor had no affect on activation or Zn2+ sensitivity of the Tin channel. These results suggested that TM3 in the hP2Y1 receptor was involved in modulating ion channel function and blocker pharmacology of the Tin channel

    An artificial fish swarm filter-based Method for constrained global optimization

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    Ana Maria A.C. Rocha, M. Fernanda P. Costa and Edite M.G.P. Fernandes, An Artificial Fish Swarm Filter-Based Method for Constrained Global Optimization, B. Murgante, O. Gervasi, S. Mirsa, N. Nedjah, A.M. Rocha, D. Taniar, B. Apduhan (Eds.), Lecture Notes in Computer Science, Part III, LNCS 7335, pp. 57–71, Springer, Heidelberg, 2012.An artificial fish swarm algorithm based on a filter methodology for trial solutions acceptance is analyzed for general constrained global optimization problems. The new method uses the filter set concept to accept, at each iteration, a population of trial solutions whenever they improve constraint violation or objective function, relative to the current solutions. The preliminary numerical experiments with a wellknown benchmark set of engineering design problems show the effectiveness of the proposed method.Fundação para a Ciência e a Tecnologia (FCT

    Partial Wave Analysis of J/ψγ(K+Kπ+π)J/\psi \to \gamma (K^+K^-\pi^+\pi^-)

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    BES data on J/ψγ(K+Kπ+π)J/\psi \to \gamma (K^+K^-\pi^+\pi^-) are presented. The KKˉK^*\bar K^* contribution peaks strongly near threshold. It is fitted with a broad 0+0^{-+} resonance with mass M=1800±100M = 1800 \pm 100 MeV, width Γ=500±200\Gamma = 500 \pm 200 MeV. A broad 2++2^{++} resonance peaking at 2020 MeV is also required with width 500\sim 500 MeV. There is further evidence for a 2+2^{-+} component peaking at 2.55 GeV. The non-KKˉK^*\bar K^* contribution is close to phase space; it peaks at 2.6 GeV and is very different from KKˉK^{*}\bar{K^{*}}.Comment: 15 pages, 6 figures, 1 table, Submitted to PL

    Plasma Wakefield Acceleration with a Modulated Proton Bunch

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    The plasma wakefield amplitudes which could be achieved via the modulation of a long proton bunch are investigated. We find that in the limit of long bunches compared to the plasma wavelength, the strength of the accelerating fields is directly proportional to the number of particles in the drive bunch and inversely proportional to the square of the transverse bunch size. The scaling laws were tested and verified in detailed simulations using parameters of existing proton accelerators, and large electric fields were achieved, reaching 1 GV/m for LHC bunches. Energy gains for test electrons beyond 6 TeV were found in this case.Comment: 9 pages, 7 figure
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