15,743 research outputs found

    Wisdom in the university

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    We live in troubled times. There are wars, poverty of millions, destruction of natural habitats and rapid extinction of species and, above all, the menace of global warming. In the light of these threats, humanity needs urgently to learn how to manage its affairs rather more wisely than it has done so far. That in turn requires that institutions of learning, above all universities, are organized for and devoted to the task. But they are not. They seek knowledge, not a wiser world. How ought universities to be organized if they are to help humanity acquire a bit more wisdom

    Are the reactions γγVV\gamma\gamma\to VV' a challenge for the factorized Pomeron at high energies?

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    We would like to point to the strong violation of the putative factorized Pomeron exchange model in the reactions γγVV\gamma\gamma\to VV' in the high-energy region where this model works fairly well in all other cases.Comment: 4 pages, LaTex, 1 fig. in postscript, minor typos corrected, to be published in Phys. Rev. D 60, 117503 (1999

    Capacities of Grassmann channels

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    A new class of quantum channels called Grassmann channels is introduced and their classical and quantum capacity is calculated. The channel class appears in a study of the two-mode squeezing operator constructed from operators satisfying the fermionic algebra. We compare Grassmann channels with the channels induced by the bosonic two-mode squeezing operator. Among other results, we challenge the relevance of calculating entanglement measures to assess or compare the ability of bosonic and fermionic states to send quantum information to uniformly accelerated frames.Comment: 33 pages, Accepted in Journal of Mathematical Physics; The role of the (fermionic) braided tensor product for quantum Shannon theory, namely capacity formulas, elucidated; The conclusion on the equivalence of Unruh effect for bosons and fermions for quantum communication purposes made clear and even more precis

    Checking Observational Purity of Procedures

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    Verifying whether a procedure is observationally pure is useful in many software engineering scenarios. An observationally pure procedure always returns the same value for the same argument, and thus mimics a mathematical function. The problem is challenging when procedures use private mutable global variables, e.g., for memoization of frequently returned answers, and when they involve recursion. We present a novel verification approach for this problem. Our approach involves encoding the procedure's code as a formula that is a disjunction of path constraints, with the recursive calls being replaced in the formula with references to a mathematical function symbol. Then, a theorem prover is invoked to check whether the formula that has been constructed agrees with the function symbol referred to above in terms of input-output behavior for all arguments. We evaluate our approach on a set of realistic examples, using the Boogie intermediate language and theorem prover. Our evaluation shows that the invariants are easy to construct manually, and that our approach is effective at verifying observationally pure procedures.Comment: FASE 201

    Molecular dynamics in shape space and femtosecond vibrational spectroscopy of metal clusters

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    We introduce a method of molecular dynamics in shape space aimed at metal clusters. The ionic degrees of freedom are described via a dynamically deformable jellium with inertia parameters derived from an incompressible, irrotational flow. The shell correction method is used to calculate the electronic potential energy surface underlying the dynamics. Our finite temperature simulations of Ag_14 and its ions, following the negative to neutral to positive scheme, demonstrate the potential of pump and probe ultrashort laser pulses as a spectroscopy of cluster shape vibrations.Comment: Latex/Revtex, 4 pages with 3 Postscript figure

    A Non-supersymmetric Interpretation of the CDF e+e-\gamma\gamma + missing E_T Event

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    The \eegg event reported recently by the CDF Collaboration has been interpreted as a signal of supersymmetry in several recent papers. In this article, we report on an alternative non-supersymmetric interpretation of the event using an extension of the standard model which contains new physics at the electroweak scale that does not effect the existing precision electroweak data. We extend the standard model by including an extra sequential generation of fermions, heavy right-handed neutrinos for all generations and an extra singly charged SU(2)-singlet Higgs boson. We discuss possible ways to discriminate this from the standard supersymemtric interpretations.Comment: 7 pages, Latex, no figure

    Total Widths And Slopes From Complex Regge Trajectories

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    Maximally complex Regge trajectories are introduced for which both Re α(s)\alpha(s) and Im α(s)\alpha(s) grow as s1ϵs^{1-\epsilon} (ϵ\epsilon small and positive). Our expression reduces to the standard real linear form as the imaginary part (proportional to ϵ\epsilon) goes to zero. A scaling formula for the total widths emerges: ΓTOT/M\Gamma_{TOT}/M\to constant for large M, in very good agreement with data for mesons and baryons. The unitarity corrections also enhance the space-like slopes from their time-like values, thereby resolving an old problem with the ρ\rho trajectory in πN\pi N charge exchange. Finally, the unitarily enhanced intercept, αρ0.525\alpha_{\rho}\approx 0.525, \nolinebreak is in good accord with the Donnachie-Landshoff total cross section analysis.Comment: 9 pages, 3 Figure

    A Conceptual Framework for Servitization in Industry 4.0: Distilling Directions for Future Research

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    Purpose: This paper focusses on developing further the recent conceptual frameworks of competitive dynamics and business-to-business value ecosystems considering the changing environment of Industry 4.0 and the particular perspective of servitization. Design/Methodology/Approach: This a conceptual paper that reviews and syntheses business model concepts in relation to competitive dynamics, collaborative business ecosystems and supply chain as evolving and reshaping manufacturing and services within Industry 4.0. Findings: The transformation of organizations in light of Industry 4.0 has led to a reframing of business models and practices, such as stakeholder value and supply chain relationships cooperating within a highly dynamic environment. In an attempt to consider the implications that Industry 4.0 has, particularly from the service perspective, this work attempts to distil directions for future research. Originality/Value: Previous studies on Industry 4.0 have articulated the reasoning about the benefits of Industry 4.0, with its paradigm shift to cyber-physical systems and revised business models. The intention of this paper, is to be able to further define collaboration and value ecosystems in order to show the interdependence and integration between organisations as applied to servitization within Industry 4.0. Moreover, this paper seeks to begin to articulate how research can be conducted to determine the degree to which the change and paradigm shift has become a reality
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