11,036 research outputs found

    On debugging in a parallel system

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    In this paper a description is given of a partly implemented parallel debugger for the Twente University Multicomputer (TUMULT). The system's basic method for exchange of data is message passing. Experience has learned that most programming errors in application software are made in calls to the kernel and the interprocess communication. The debugger is intended to be used for locating bugs at this level in the application software. It is assumed that basic blocks of the debuggee can be debugged using a traditional sequential sourcelevel debugger

    Economic Efficiency of U.S. Organic Versus Conventional Dairy Farms: Evidence from 2005 and 2010

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    We estimate an input distance function for U.S. dairy farming to examine the competitiveness of organic and non-organic dairy production by system and size. Across organic/non-organic systems and size classes, size is the major determinant of competitiveness based on various measures of productivity and returns to scale.Organic, Non-organic, Input Distance Function, Livestock Production/Industries, Production Economics,

    Parallel-plate viscometer

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    Viscometer consists of movable vertical rod with one optical flat fixed to its lower end and centered over second optical flat held rigidly parallel to moveable flat. Two perforated diaphragms of thin metal permit limited amount of vertical movement of rod carrying movable flat, but resist lateral movement

    Electron-phonon coupling and superconductivity-induced distortion of the phonon lineshape in V3_3Si

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    Phonon measurements in the A15-type superconductors were complicated in the past because of the unavailability of large single crystals for inelastic neutron scattering, e.g., in the case of Nb3_3Sn, or unfavorable neutron scattering properties in the case of V3_3Si. Hence, only few studies of the lattice dynamical properties with momentum resolved methods were published, in particular below the superconducting transition temperature TcT_c. Here, we overcome these problems by employing inelastic x-ray scattering and report a combined experimental and theoretical investigation of lattice dynamics in V3_3Si with the focus on the temperature-dependent properties of low-energy acoustic phonon modes in several high-symmetry directions. We paid particular attention to the evolution of the soft phonon mode of the structural phase transition observed in our sample at Ts=18.9KT_s=18.9\,\rm{K}, i.e., just above the measured superconducting phase transition at Tc=16.8KT_c=16.8\,\rm{K}. Theoretically, we predict lattice dynamics including electron-phonon coupling based on density-functional-perturbation theory and discuss the relevance of the soft phonon mode with regard to the value of TcT_c. Furthermore, we explain superconductivityinduced anomalies in the lineshape of several acoustic phonon modes using a model proposed by Allen et al., [Phys. Rev. B 56, 5552 (1997)]

    Evaluation of anomalies observed on film from S-190A flight system calibration test

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    Due to a persistent problem of scratched film from testing of the Skylab S-190A system, a series of tests were designed to identify the cause of the film scratching. The procedures followed in this test for pretest handling and packaging of the film, the makeup of the rolls for processing, and the results of the processed film evaluation are reported

    The Subcolonization and Buildup of \u3ci\u3eTetrastichus Julis,\u3c/i\u3e (Hymenoptera: Eulophidae) a Larval Parasitoid of the Cereal Leaf Beetle, (Coleoptera: Chrysomelidae) in the Lower Peninsula of Michigan

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    Following initial establishment of the parasitoid, Tetrastichus julis (Walker), at a carefully managed field nursery, releases of parasitized Oulema melanopus larvae were made by Michigan county agents at preselected sites throughout the lower peninsula during 1970-74. A follow-up recovery program during 1971-75 revealed continued dispersion and population increase for T. julis. An independent census verified the increasing rates of parasitism

    Pulsed beams as field probes for precision measurement

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    We describe a technique for mapping the spatial variation of static electric, static magnetic, and rf magnetic fields using a pulsed atomic or molecular beam. The method is demonstrated using a beam designed to measure the electric dipole moment of the electron. We present maps of the interaction region, showing sensitivity to (i) electric field variation of 1.5 V/cm at 3.3 kV/cm with a spatial resolution of 15 mm; (ii) magnetic field variation of 5 nT with 25 mm resolution; (iii) radio-frequency magnetic field amplitude with 15 mm resolution. This new diagnostic technique is very powerful in the context of high-precision atomic and molecular physics experiments, where pulsed beams have not hitherto found widespread application.Comment: 6 pages, 12 figures. Figures heavily compressed to comply with arxiv's antediluvian file-size polic

    Core hole-electron correlation in coherently coupled molecules

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    We study the core hole-electron correlation in coherently coupled molecules by energy dispersive near edge X-ray absorption fine-structure spectroscopy. In a transient phase, which exists during the transition between two bulk arrangements, 1,4,5,8-naphthalene-tetracarboxylicacid-dianhydride multilayer films exhibit peculiar changes of the line shape and energy position of the X-ray absorption signal at the C K-edge with respect to the bulk and gas phase spectra. By a comparison to a theoretical model based on a coupling of transition dipoles, which is established for optical absorption, we demonstrate that the observed spectroscopic differences can be explained by an intermolecular delocalized core hole-electron pair. By applying this model we can furthermore quantify the coherence length of the delocalized core-exciton.Comment: 5 pages, 3 figures, Accepted Version, PRL, minor wording change

    Intensive versus Extensive Dairy Production Systems: Dairy States in the Eastern and Midwestern U.S. and Key Pasture Countries the E.U.: Determining the Competitive Edge

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    In recent years, significant structural and production system changes have been noted in the U.S. and European Union, as well as increased interest in pasture-based dairy systems. Technical efficiency, returns to scale, and farm characteristics are compared by size and production system in traditional U.S. dairy states and E.U. countries.U.S., EU Countries, Dairy Systems, Technical Efficiency, Returns To Scale, Size, Technology, Land Prices, Production Economics, Q12,

    Active Semi-Supervised Learning Using Sampling Theory for Graph Signals

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    We consider the problem of offline, pool-based active semi-supervised learning on graphs. This problem is important when the labeled data is scarce and expensive whereas unlabeled data is easily available. The data points are represented by the vertices of an undirected graph with the similarity between them captured by the edge weights. Given a target number of nodes to label, the goal is to choose those nodes that are most informative and then predict the unknown labels. We propose a novel framework for this problem based on our recent results on sampling theory for graph signals. A graph signal is a real-valued function defined on each node of the graph. A notion of frequency for such signals can be defined using the spectrum of the graph Laplacian matrix. The sampling theory for graph signals aims to extend the traditional Nyquist-Shannon sampling theory by allowing us to identify the class of graph signals that can be reconstructed from their values on a subset of vertices. This approach allows us to define a criterion for active learning based on sampling set selection which aims at maximizing the frequency of the signals that can be reconstructed from their samples on the set. Experiments show the effectiveness of our method.Comment: 10 pages, 6 figures, To appear in KDD'1
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