17,845 research outputs found

    Compact in-memory representation of XML data : design and implementation of a compressed DOM for data-centric documents

    Get PDF
    Over recent years XML has evolved from a document exchange format to a multi-purpose data storage and retrieval solution. To make use of the full potential of XML in the domain of large, data-centric documents it is necessary to have easy and fast access to individual data elements. We describe an implementation of the Document Object Model (DOM) that is designed with these objectives in mind. It uses compression to allow large documents to be stored in the computer's main memory. Query-relevant DOM methods are optimised to work on top of the created data structure. Measurements indicate that compression up to a factor of 5 is possible without losing the ability to directly address individual elements. No prior decompression is needed to query and locate nodes

    The Relevance of Evolutionary Science For Economic Theory and Policy

    Get PDF
    NSF’s “Dear Colleague Letter” reflects the widely perceived need to go beyond current economic theory in the formulation of public policy. At the same time, there is a profound lack of unity among the disciplines that comprise the behavioral, social, and economic sciences. This white paper emphasizes the relevance of evolutionary science as a way to integrate the SBE sciences, similar to the integration that is more advanced in the biological sciences. Modern evolutionary science is broadly construed to include cultural in addition to biological evolution and the study of neural and psychological mechanisms (proximate causation) in addition to the environmental factors that brought the mechanisms into existence and result in the expression of specific behaviors (ultimate causation). It provides an exceptionally useful set of theoretical and empirical tools for integrating the many disciplines in the biological and SBE sciences required to formulate economic theory and public policy for the 21st century. The task of integration is already in progress and can be applied to the formulation of public policy without a long academic time lag. We therefore call for integration across disciplines and evolutionary science as an integrative framework to be recognized as a funding priority by NSF.

    Bitter taste stimuli induce differential neural codes in mouse brain.

    Get PDF
    A growing literature suggests taste stimuli commonly classified as "bitter" induce heterogeneous neural and perceptual responses. Here, the central processing of bitter stimuli was studied in mice with genetically controlled bitter taste profiles. Using these mice removed genetic heterogeneity as a factor influencing gustatory neural codes for bitter stimuli. Electrophysiological activity (spikes) was recorded from single neurons in the nucleus tractus solitarius during oral delivery of taste solutions (26 total), including concentration series of the bitter tastants quinine, denatonium benzoate, cycloheximide, and sucrose octaacetate (SOA), presented to the whole mouth for 5 s. Seventy-nine neurons were sampled; in many cases multiple cells (2 to 5) were recorded from a mouse. Results showed bitter stimuli induced variable gustatory activity. For example, although some neurons responded robustly to quinine and cycloheximide, others displayed concentration-dependent activity (p<0.05) to quinine but not cycloheximide. Differential activity to bitter stimuli was observed across multiple neurons recorded from one animal in several mice. Across all cells, quinine and denatonium induced correlated spatial responses that differed (p<0.05) from those to cycloheximide and SOA. Modeling spatiotemporal neural ensemble activity revealed responses to quinine/denatonium and cycloheximide/SOA diverged during only an early, at least 1 s wide period of the taste response. Our findings highlight how temporal features of sensory processing contribute differences among bitter taste codes and build on data suggesting heterogeneity among "bitter" stimuli, data that challenge a strict monoguesia model for the bitter quality

    Method and apparatus for reliable inter-antenna baseline determination

    Get PDF
    Disclosed is a method for inter-antenna baseline determination that uses an antenna configuration comprising a pair of relatively closely spaced antennas and other pairs of distant antennas. The closely spaced pair provides a short baseline having an integer ambiguity that may be searched exhaustively to identify the correct set of integers. This baseline is then used as a priori information to aid the determination of longer baselines that, once determined, may be used for accurate run time attitude determination

    An Acquisition Model to Emulate: An evaluation of the 1988 Packard Commission report

    Get PDF

    Critical superfluid velocity in a trapped dipolar gas

    Full text link
    We investigate the superfluid properties of a dipolar Bose-Einstein condensate (BEC) in a fully three-dimensional trap. Specifically, we calculate a superfluid critical velocity for this system by applying the Landau criterion to its discrete quasiparticle spectrum. We test this critical velocity by direct numerical simulation of condensate depletion as a blue-detuned laser moves through the condensate. In both cases, the presence of the roton in the spectrum serves to lower the critical velocity beyond a critical particle number. Since the shape of the dispersion, and hence the roton minimum, is tunable as a function of particle number, we thereby propose an experiment that can simultaneously measure the Landau critical velocity of a dipolar BEC and demonstrate the presence of the roton in this system.Comment: 5 pages, 4 figures, version accepted to PR
    corecore