2,767 research outputs found

    Jewish Palestine.

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    Payout Taxes and the Allocation of Investment

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    When corporate payout is taxed, internal equity (retained earnings) is cheaper than external equity (share issues). High taxes will favor firms who can finance internally. If there are no perfect substitutes for equity finance, payout taxes may thus change the investment behavior of firms. Using an international panel with many changes in payout taxes, we show that this prediction holds well. Payout taxes have a large impact on the dynamics of corporate investment and growth. Investment is “locked in” in profitable firms when payout is heavily taxed. Thus, apart from any aggregate effects, payout taxes change the allocation of capital.

    The Elliptic Double-Box Integral: Massless Amplitudes Beyond Polylogarithms

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    We derive an analytic representation of the ten-particle, two-loop double-box integral as an elliptic integral over weight-three polylogarithms. To obtain this form, we first derive a four-fold, rational (Feynman-)parametric representation for the integral, expressed directly in terms of dual-conformally invariant cross-ratios; from this, the desired form is easily obtained. The essential features of this integral are illustrated by means of a simplified toy model, and we attach the relevant expressions for both integrals in ancillary files. We propose a normalization for such integrals that renders all of their polylogarithmic degenerations pure, and we discuss the need for a new 'symbology' of iterated elliptic/polylogarithmic integrals in order to bring them to a more canonical form.Comment: 4+2 pages, 2 figures. Explicit results are included as ancillary files. v2: minor changes made for clarification; references adde

    Draft Genome Sequence of Staphylococcus pseudintermedius Strain 13-13613, Isolated from a Case of Canine Pyoderma

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    Here, we report the draft genome sequence of Staphylococcus pseudintermedius strain 13-13613, isolated from a case of canine pyoderma. The draft genome contains 2,533,486 bp in 570 contigs

    Programming with C++ concepts

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    AbstractThis paper explores the definition, applications, and limitations of concepts and concept maps in C++, with a focus on library composition. We also compare and contrast concepts to adaptation mechanisms in other languages.Efficient, non-intrusive adaptation mechanisms are essential when adapting data structures to a library’s API. Development with reusable components is a widely practiced method of building software. Components vary in form, ranging from source code to non-modifiable binary libraries. The Concepts language features, slated to appear in the next version of C++, have been designed with such compositions in mind, promising an improved ability to create generic, non-intrusive, efficient, and identity-preserving adapters.We report on two cases of data structure adaptation between different libraries, and illustrate best practices and idioms. First, we adapt GUI widgets from several libraries, with differing APIs, for use with a generic layout engine. We further develop this example to describe the run-time concept idiom, extending the applicability of concepts to domains where run-time polymorphism is required. Second, we compose an image processing library and a graph algorithm library, by making use of a transparent adaptation layer, enabling the efficient application of graph algorithms to the image processing domain. We use the adaptation layer to realize a few key algorithms, and report little or no performance degradation

    Verhaltensmodell fĂĽr Softwareagenten im Public Goods Game

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    Gegenstand der vorliegenden Arbeit ist das Verhaltensmodell von Softwareagenten in einem Public Goods Game. Agenten im Sinne der Arbeit besitzen jeweils eigene, individuelle Ziele und müssen sich im Hinblick auf ein übergeordnetes Gesamtziel im Multiagentensystem koordinieren. Dabei hängen die individuell und kollektiv erzielbaren Ergebnisse von der Wahl der Verhaltensmodelle der Agenten ab. Die Wahl eines rein eigennützigen Verhaltens kann zu Nutzeneinbußen führen; die Wahl eines selbstlosen Verhaltens kann die individuell erzielbaren Ergebnisse eines Agenten massiv beeinträchtigen, falls andere Agenten im System eigennützig spielen. Die Auswirkungen verschiedener, aus der sozio-ökonomischen Theorie entlehnter Verhaltensmodelle in unterschiedlich gestalteten Agenten-Gesellschaften wird mittels einer Simulation untersucht. Die vorliegende Arbeit soll somit einen Beitrag liefern, um auf Basis deskriptiver sozio-ökonomischer Verhaltensmodelle Aussagen über das Verhalten von Softwareagenten (präskriptive Modelle) zu erlauben. Die Erkenntnisse helfen Entwicklern von Multiagentensystemen bei der Implementierung eines problemadäquaten Agentenverhaltens

    Design of Low Complexity Model Reference Adaptive Controllers

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    Flight research experiments have demonstrated that adaptive flight controls can be an effective technology for improving aircraft safety in the event of failures or damage. However, the nonlinear, timevarying nature of adaptive algorithms continues to challenge traditional methods for the verification and validation testing of safety-critical flight control systems. Increasingly complex adaptive control theories and designs are emerging, but only make testing challenges more difficult. A potential first step toward the acceptance of adaptive flight controllers by aircraft manufacturers, operators, and certification authorities is a very simple design that operates as an augmentation to a non-adaptive baseline controller. Three such controllers were developed as part of a National Aeronautics and Space Administration flight research experiment to determine the appropriate level of complexity required to restore acceptable handling qualities to an aircraft that has suffered failures or damage. The controllers consist of the same basic design, but incorporate incrementally-increasing levels of complexity. Derivations of the controllers and their adaptive parameter update laws are presented along with details of the controllers implementations

    Handling Qualities of Model Reference Adaptive Controllers with Varying Complexity for Pitch-Roll Coupled Failures

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    Three model reference adaptive controllers (MRAC) with varying levels of complexity were evaluated on a high performance jet aircraft and compared along with a baseline nonlinear dynamic inversion controller. The handling qualities and performance of the controllers were examined during failure conditions that induce coupling between the pitch and roll axes. Results from flight tests showed with a roll to pitch input coupling failure, the handling qualities went from Level 2 with the baseline controller to Level 1 with the most complex MRAC tested. A failure scenario with the left stabilator frozen also showed improvement with the MRAC. Improvement in performance and handling qualities was generally seen as complexity was incrementally added; however, added complexity usually corresponds to increased verification and validation effort required for certification. The tradeoff between complexity and performance is thus important to a controls system designer when implementing an adaptive controller on an aircraft. This paper investigates this relation through flight testing of several controllers of vary complexity

    Optical patterning of trapped charge in nitrogen-doped diamond

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    The nitrogen-vacancy (NV) centre in diamond is emerging as a promising platform for solid-state quantum information processing and nanoscale metrology. Of interest in these applications is the manipulation of the NV charge, which can be attained by optical excitation. Here we use two-color optical microscopy to investigate the dynamics of NV photo-ionization, charge diffusion, and trapping in type-1b diamond. We combine fixed-point laser excitation and scanning fluorescence imaging to locally alter the concentration of negatively charged NVs, and to subsequently probe the corresponding redistribution of charge. We uncover the formation of spatial patterns of trapped charge, which we qualitatively reproduce via a model of the interplay between photo-excited carriers and atomic defects. Further, by using the NV as a probe, we map the relative fraction of positively charged nitrogen upon localized optical excitation. These observations may prove important to transporting quantum information between NVs or to developing three-dimensional, charge-based memories
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