26,837 research outputs found

    Graphics shadowing analysis

    Get PDF
    Visual image is generated on cathode-ray tube screen to scale and is constructed according to dimensions of specified craft. Once displayed, image may be manipulated by several different means

    Mapping Atomic Motions with Electrons: Toward the Quantum Limit to Imaging Chemistry

    Get PDF
    Recent advances in ultrafast electron and X-ray diffraction have pushed imaging of structural dynamics into the femtosecond time domain, that is, the fundamental time scale of atomic motion. New physics can be reached beyond the scope of traditional diffraction or reciprocal space imaging. By exploiting the high time resolution, it has been possible to directly observe the collapse of nearly innumerable possible nuclear motions to a few key reaction modes that direct chemistry. It is this reduction in dimensionality in the transition state region that makes chemistry a transferable concept, with the same class of reactions being applicable to synthetic strategies to nearly arbitrary levels of complexity. The ability to image the underlying key reaction modes has been achieved with resolution to relative changes in atomic positions to better than 0.01 Ã…, that is, comparable to thermal motions. We have effectively reached the fundamental space-time limit with respect to the reaction energetics and imaging the acting forces. In the process of ensemble measured structural changes, we have missed the quantum aspects of chemistry. This perspective reviews the current state of the art in imaging chemistry in action and poses the challenge to access quantum information on the dynamics. There is the possibility with the present ultrabright electron and X-ray sources, at least in principle, to do tomographic reconstruction of quantum states in the form of a Wigner function and density matrix for the vibrational, rotational, and electronic degrees of freedom. Accessing this quantum information constitutes the ultimate demand on the spatial and temporal resolution of reciprocal space imaging of chemistry. Given the much shorter wavelength and corresponding intrinsically higher spatial resolution of current electron sources over X-rays, this Perspective will focus on electrons to provide an overview of the challenge on both the theory and the experimental fronts to extract the quantum aspects of molecular dynamics

    Alcohol, assault and licensed premises in inner-city areas

    Get PDF
    This report contains eight linked feasibility studies conducted in Cairns during 2010. These exploratory studies examine the complex challenges of compiling and sharing information about incidents of person-to-person violence in a late night entertainment precinct (LNEP). The challenges were methodological as well as logistical and ethical. The studies look at how information can be usefully shared, while preserving the confidentiality of those involved. They also examine how information can be compiled from routinely collected sources with little or no additional resources, and then shared by the agencies that are providing and using the information.Although the studies are linked, they are also stand-alone and so can be published in peer-reviewed literature. Some have already been published, or are ‘in press’ or have been submitted for review. Others require the NDLERF board’s permission to be published as they include data related more directly to policing, or they include information provided by police.The studies are incorporated into the document under section headings. In each section, they are introduced and then presented in their final draft form. The final published form of each paper, however, is likely to be different from the draft because of journal and reviewer requirements. The content, results and implications of each study are discussed in summaries included in each section.Funded by the National Drug Law Enforcement Research Fund, an initiative of the National Drug StrategyAlan R Clough (PhD) School of Public Health, Tropical Medicine and Rehabilitation Sciences James Cook UniversityCharmaine S Hayes-Jonkers (BPsy, BSocSci (Hon1)) James Cook University, Cairns.Edward S Pointing (BPsych) James Cook University, Cairns

    Adhesive coating eliminated in new honeycomb-core fabrication process

    Get PDF
    Technique eliminates use of silicone-based adhesive material as bonding medium. Adhesive requires precise time-temperature cure. Prepreg resin is used as bonding medium, and each layer is laminated together to form honeycomb billet. Process can be used in any application where nonmetallic honeycomb core is being fabricated

    Travelling Salesman Problem with a Center

    Full text link
    We study a travelling salesman problem where the path is optimized with a cost function that includes its length LL as well as a certain measure CC of its distance from the geometrical center of the graph. Using simulated annealing (SA) we show that such a problem has a transition point that separates two phases differing in the scaling behaviour of LL and CC, in efficiency of SA, and in the shape of minimal paths.Comment: 4 pages, minor changes, accepted in Phys.Rev.

    Low myo-inositol and high glutamine levels in brain are associated with neuropsychological deterioration after induced hyperammonemia

    Get PDF
    The neuropsychological effect of hyperammonemia is variable. This study tests the hypothesis that the effect of ammonia on the neuropsychological function in patients with cirrhosis is determined by the ability of the brain to buffer ammonia-induced increase in glutamine within the astrocyte by losing osmolytes like myo-inositol (mI) and not by the magnitude of the induced hyperammonemia. Fourteen cirrhotic patients with no evidence of overt hepatic encephalopathy were given a 75-g amino acid (aa) solution mimicking the hemoglobin molecule to induce hyperammonemia. Measurement of a battery of neuropsychological function tests including immediate memory, ammonia, aa, and short-echo time proton magnetic resonance spectroscopy were performed before and 4 h after administration of the as solution. Eight patients showed deterioration in the Immediate Memory Test at 4 h. Demographic factors, severity of liver disease, change in plasma ammonia, and as profiles after the as solution were similar in those that showed a deterioration compared with those who did not. In patients who showed deterioration in the memory test, the mI-to-creatine ratio (mI/Cr) was significantly lower at baseline than those that did not deteriorate. In contrast, the glutamate/glutamine-to-Cr ratio was significantly greater in the patients that deteriorated. The observation that deterioration in the memory test scores was greater in those with lower mI/Cr supports the hypothesis that the neuropsychological effects of induced hyperammonemia is determined by the capacity of the brain to handle ammonia-induced increase in glutamine

    A heralded quantum gate between remote quantum memories

    Full text link
    We demonstrate a probabilistic entangling quantum gate between two distant trapped ytterbium ions. The gate is implemented between the hyperfine "clock" state atomic qubits and mediated by the interference of two emitted photons carrying frequency encoded qubits. Heralded by the coincidence detection of these two photons, the gate has an average fidelity of 90+-2%. This entangling gate together with single qubit operations is sufficient to generate large entangled cluster states for scalable quantum computing

    Completeness and Incompleteness of Synchronous Kleene Algebra

    Get PDF
    Synchronous Kleene algebra (SKA), an extension of Kleene algebra (KA), was proposed by Prisacariu as a tool for reasoning about programs that may execute synchronously, i.e., in lock-step. We provide a countermodel witnessing that the axioms of SKA are incomplete w.r.t. its language semantics, by exploiting a lack of interaction between the synchronous product operator and the Kleene star. We then propose an alternative set of axioms for SKA, based on Salomaa's axiomatisation of regular languages, and show that these provide a sound and complete characterisation w.r.t. the original language semantics.Comment: Accepted at MPC 201
    • …
    corecore