3,968 research outputs found

    Scanned Image Projection System Employing Intermediate Image Plane

    Get PDF
    In imaging system, a spatial light modulator is configured to produce images by scanning a plurality light beams. A first optical element is configured to cause the plurality of light beams to converge along an optical path defined between the first optical element and the spatial light modulator. A second optical element is disposed between the spatial light modulator and a waveguide. The first optical element and the spatial light modulator are arranged such that an image plane is created between the spatial light modulator and the second optical element. The second optical element is configured to collect the diverging light from the image plane and collimate it. The second optical element then delivers the collimated light to a pupil at an input of the waveguide

    Quantized Nambu-Poisson Manifolds and n-Lie Algebras

    Full text link
    We investigate the geometric interpretation of quantized Nambu-Poisson structures in terms of noncommutative geometries. We describe an extension of the usual axioms of quantization in which classical Nambu-Poisson structures are translated to n-Lie algebras at quantum level. We demonstrate that this generalized procedure matches an extension of Berezin-Toeplitz quantization yielding quantized spheres, hyperboloids, and superspheres. The extended Berezin quantization of spheres is closely related to a deformation quantization of n-Lie algebras, as well as the approach based on harmonic analysis. We find an interpretation of Nambu-Heisenberg n-Lie algebras in terms of foliations of R^n by fuzzy spheres, fuzzy hyperboloids, and noncommutative hyperplanes. Some applications to the quantum geometry of branes in M-theory are also briefly discussed.Comment: 43 pages, minor corrections, presentation improved, references adde

    Remote video monitoring is another example of “dying on the machine” for critically ill patients

    Get PDF
    A critical appraisal and clinical application of Hardin SR, Dienemann J, Rudisill P, Mills KK. Inpatient fall prevention: use of in-room webcams. J Patient Saf. 2013 Mar;9(1):29-35. doi: 10.1097/PTS.0b013e3182753e4

    Emerging Scholars Program—A PLTL-CS Program That Increases Recruitment and Retention of Women in the Major

    Get PDF
    The Emerging Scholars Program (ESP) in Computer Science is a Peer Led Team Learning (PLTL) approach to bringing undergraduates new to the discipline together with peer mentors to work on computational problems, and to expose them to the broad array of disciplines within computer science. This program demonstrates that computer science is necessarily a collaborative activity that focuses more on problem solving and algorithmic thinking than on programming. In spring 2012 the computer science department at an urban research university university completed the 9th iteration of ESP, with 104 women and 36 men completing the program. Our evaluation data indicates that ESP increased enrollment in the computer science major. 47% of students who took ESP along with the introduction to computer programming course at the university study site during this study majored in computer science. In addition, survey results indicated that a large majority of students intended to take another computer science course, were enthusiastic about the program, and found the workshop topics exciting and engaging. Participants reported that they learned more about computer science in ESP, and would recommend ESP to others

    Experimental demonstration of quantum effects in the operation of microscopic heat engines

    Full text link
    The heat engine, a machine that extracts useful work from thermal sources, is one of the basic theoretical constructs and fundamental applications of classical thermodynamics. The classical description of a heat engine does not include coherence in its microscopic degrees of freedom. By contrast, a quantum heat engine might possess coherence between its internal states. Although the Carnot efficiency cannot be surpassed, and coherence can be performance degrading in certain conditions, it was recently predicted that even when using only thermal resources, internal coherence can enable a quantum heat engine to produce more power than any classical heat engine using the same resources. Such a power boost therefore constitutes a quantum thermodynamic signature. It has also been shown that the presence of coherence results in the thermodynamic equivalence of different quantum heat engine types, an effect with no classical counterpart. Microscopic heat machines have been recently implemented with trapped ions, and proposals for heat machines using superconducting circuits and optomechanics have been made. When operated with standard thermal baths, however, the machines implemented so far have not demonstrated any inherently quantum feature in their thermodynamic quantities. Here we implement two types of quantum heat engines by use of an ensemble of nitrogen-vacancy centres in diamond, and experimentally demonstrate both the coherence power boost and the equivalence of different heat-engine types. This constitutes the first observation of quantum thermodynamic signatures in heat machines

    Political Ideology, Trust, and Cooperation: In-group Favoritism among Republicans and Democrats during a US National Election

    Get PDF
    Theories suggest that political ideology relates to cooperation, with conservatives being more likely to pursue selfish outcomes, and liberals more likely to pursue egalitarian outcomes. In study 1, we examine how political ideology and political party affiliation (Republican vs. Democrat) predict cooperation with a partner who self-identifies as Republican or Democrat in two samples before (n = 362) and after (n = 366) the 2012 US presidential election. Liberals show slightly more concern for their partners’ outcomes compared to conservatives (study 1), and in study 2 this relation is supported by a meta-analysis (r =.15). However, in study 1, political ideology did not relate to cooperation in general. Both Republicans and Democrats extend more cooperation to their in-group relative to the out-group, and this is explained by expectations of cooperation from in-group versus out-group members. We discuss the relation between political ideology and cooperation within and between groups

    Homomorphisms are a good basis for counting small subgraphs

    Get PDF
    We introduce graph motif parameters, a class of graph parameters that depend only on the frequencies of constant-size induced subgraphs. Classical works by Lov\'asz show that many interesting quantities have this form, including, for fixed graphs HH, the number of HH-copies (induced or not) in an input graph GG, and the number of homomorphisms from HH to GG. Using the framework of graph motif parameters, we obtain faster algorithms for counting subgraph copies of fixed graphs HH in host graphs GG: For graphs HH on kk edges, we show how to count subgraph copies of HH in time kO(k)n0.174k+o(k)k^{O(k)}\cdot n^{0.174k + o(k)} by a surprisingly simple algorithm. This improves upon previously known running times, such as O(n0.91k+c)O(n^{0.91k + c}) time for kk-edge matchings or O(n0.46k+c)O(n^{0.46k + c}) time for kk-cycles. Furthermore, we prove a general complexity dichotomy for evaluating graph motif parameters: Given a class C\mathcal C of such parameters, we consider the problem of evaluating fCf\in \mathcal C on input graphs GG, parameterized by the number of induced subgraphs that ff depends upon. For every recursively enumerable class C\mathcal C, we prove the above problem to be either FPT or #W[1]-hard, with an explicit dichotomy criterion. This allows us to recover known dichotomies for counting subgraphs, induced subgraphs, and homomorphisms in a uniform and simplified way, together with improved lower bounds. Finally, we extend graph motif parameters to colored subgraphs and prove a complexity trichotomy: For vertex-colored graphs HH and GG, where HH is from a fixed class H\mathcal H, we want to count color-preserving HH-copies in GG. We show that this problem is either polynomial-time solvable or FPT or #W[1]-hard, and that the FPT cases indeed need FPT time under reasonable assumptions.Comment: An extended abstract of this paper appears at STOC 201
    corecore