3,374 research outputs found

    Manifestation of quantum resonant effects in the atom-optical delta-kicked accelerator

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    In this thesis we investigate quantum resonant effects in the atom-optical ὁ-kicked accelerator. Using Floquet analysis, we theoretically study the time evolution of quantum systems which have a classical counterpart that exhibits chaotic dynamics. We introduce quantum resonance and quantum antiresonance features of the quantum ὁ -kicked rotor by setting the pulse period to an integer multiple of the half-Talbot time. The model is generalised to the atom-optical ὁ -kicked accelerator by considering thermal alkali atoms subject to a periodically pulsed standing wave potential formed from counter-propagating laser beams. The dynamics of the momentum distribution is analysed by evaluating the momentum moments and momentum cumulants. We derive analytic solutions for these observables for the ultracold and thermal limiting cases, and observe fractional quantum resonant phenomena. Simulations have been developed to examine the time evolution for individual momentum eigenstates, which we use to construct a non-interacting finite temperature gas, based upon a Monte Carlo method. We investigate the temperature dependence of the ὁ-kicked rotor, neglecting gravitational effects, and show that the atomic dynamics is highly sensitive to the initial momentum width of the gas. A generalisation of the model to quantify the transition between the ultracold and thermal temperature regimes of the atom-optical ὁ -kicked accelerator is examined using linear regression analysis. High order quantum resonance features are found to be sensitive to the relative acceleration between the atomic gas and the pulsed optical standing wave. We assess the dependence of the ὁ -kicked accelerator upon gravitational acceleration, quantifying the width of the high order quantum resonance features, which we use to assess the prospect for precision measurement using a finite temperature gas

    Fast Computation of Smith Forms of Sparse Matrices Over Local Rings

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    We present algorithms to compute the Smith Normal Form of matrices over two families of local rings. The algorithms use the \emph{black-box} model which is suitable for sparse and structured matrices. The algorithms depend on a number of tools, such as matrix rank computation over finite fields, for which the best-known time- and memory-efficient algorithms are probabilistic. For an \nxn matrix AA over the ring \Fzfe, where fef^e is a power of an irreducible polynomial f \in \Fz of degree dd, our algorithm requires \bigO(\eta de^2n) operations in \F, where our black-box is assumed to require \bigO(\eta) operations in \F to compute a matrix-vector product by a vector over \Fzfe (and η\eta is assumed greater than \Pden). The algorithm only requires additional storage for \bigO(\Pden) elements of \F. In particular, if \eta=\softO(\Pden), then our algorithm requires only \softO(n^2d^2e^3) operations in \F, which is an improvement on known dense methods for small dd and ee. For the ring \ZZ/p^e\ZZ, where pp is a prime, we give an algorithm which is time- and memory-efficient when the number of nontrivial invariant factors is small. We describe a method for dimension reduction while preserving the invariant factors. The time complexity is essentially linear in μnrelogp,\mu n r e \log p, where μ\mu is the number of operations in \ZZ/p\ZZ to evaluate the black-box (assumed greater than nn) and rr is the total number of non-zero invariant factors. To avoid the practical cost of conditioning, we give a Monte Carlo certificate, which at low cost, provides either a high probability of success or a proof of failure. The quest for a time- and memory-efficient solution without restrictions on the number of nontrivial invariant factors remains open. We offer a conjecture which may contribute toward that end.Comment: Preliminary version to appear at ISSAC 201

    Why the epistemologies of trust researchers matter

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    In this thought piece we take stock of and evaluate the nature of knowledge production in the field of trust research by examining the epistemologies of 167 leading trust scholars, who responded to a short survey. Following a brief review of major epistemological perspectives we discuss the nature of the prevalent views and their geographical distribution within our field. We call on trust researchers to engage in epistemological reflection, develop their own awareness of alternative epistemologies, and ensure their work draws on and cites relevant research contrary to their preferred epistemological approach. To support this we ask editors of relevant journals to foster pluralism in trust research, publishing work from a range of epistemologies

    Effect of card play on perceived life satisfaction and self esteem of older adults

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    STATEMENT OF THE PROBLEM: The problem of this study was to (a) assess the effect of playing cards on the level of perception of life satisfaction and self-esteem in older adults and (b) determine if there was any difference in the perceived level of life satisfaction and self-esteem between older adults who played cards with other people compared with those who played cards on a computer. PURPOSE OF THE STUDY: The purpose of this study was to examine a potentially cost effective way to improve the level of perception of life satisfaction and self-esteem of the older adult. METHODS: Single-subject repeated measures A-B-A design was used for the three phase experiment. Data were collected from all subjects across a total of six weeks. Phase (A) was the establishment of the baseline before the start of treatment phase (B). Subjects in the study were tested with two measurement instruments of Life Satisfaction and Self-Esteem before treatment of card play on the computer or face-to-face card play, were administered. Midpoint and end-treatment tests were given at the second and fourth weeks. These two testing sessions measured phase (B), the treatment phase of the experiment. Two weeks after the treatment phase, tests were given as the post-treatment (A) last phase of the experiment, measuring the subjects post treatment return to baseline. Data analysis: data collected from the four testing periods were entered into a Microsoft 2007 Excel file. Individual and combined trend line charts were generated for descriptive analysis, interpretation, and explanation of the trend lines across times of testing.Submitted to the faculty of the University Graduate School in partial fulfillment of the requirements for the degree Master of Science in the School of Health, Physical Education, and Recreation Indiana University May 201

    Biology and Management of Sablefish, Anoplopoma fimbria: Papers from the International Symposium on the Biology and Management of Sablefish, Seattle, Washington, 13-15 April 1993

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    At its june 1990 annual meeting, the Technical Subcommittee (TSC) of the Canada-U.S. Groundfish Committee recommended that scientists and managers working on sablefish, Anoplopoma fimbria, issues convene to present and discuss the results of their recent research. Thorough knowledge of the biology and population dynamics of this species is essential for its effective management, especially considering its commercial importance. TSC representatives from both countries recognized that a great deal ofactive research has been conducted on this species since the International Sablefish Symposium was held in Anchorage, Alaska, in March 1983 (Melteff, 1983). As a result of this recommendation, the International Symposium on the Biology and Management of Sablefish (ISBMS) was convened April 13-15, 1993, at the Alaska Fisheries Science Center in Seattle, Washington. (PDF file contains 286 pages.

    The Problem of English Evangelicals and Homosexuality: A Girardian Study of Popular English Evangelical Writings on Homosexuality 1960-2010

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    English evangelicals in the period 1960-2010 have been marked by their negativity and violence towards gays. However, they have also consistently condemned homophobia during this period (and often seemed unaware of their own complicity in it). This thesis draws on the work of René Girard to analyse popular English evangelical writings and the ways in which they have implicitly encouraged violence against gays even whilst explicitly condemning it. This analysis of evangelical writings on homosexuality is placed in its historical context by drawing on the work of relevant historians and social scientists. It is further contextualised by reference to an analysis of evangelical writings on holiness during the same period. The thesis argues that English evangelical violence towards gays is a byproduct of internal conflicts within English evangelicalism. Gays are seen as prototypical liberals and treated as scapegoats for an evangelical identity crisis. Homophobia and fundamentalism are discussed and rejected as alternative explanations. It is argued that the crisis in English evangelicalism in the period 1960-2010 has had a distorting effect not only on approaches to homosexuality, but also to other areas of English evangelical spirituality. Finally, evangelical atonement theology is examined, and found to contain both elements that legitimise sacred violence and resources to help evangelicals resist it

    The pervasiveness and implications of statistical misconceptions among academics with a special interest in business research methods

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    Statistics play a very important role in business research, particularly in studies that choose to use quantitative or mixed methods. Alongside statistical analysis, aspects related to research design (such as sampling, reliability and validity issues) require a good grounding in statistical concepts reinforced by careful practice to avoid potential mistakes arising from statistical misconceptions. Although quite a considerable number of published studies have focused on students' faulty thinking regarding statistical concepts, little research explores the extent to which these are also held by academics who are their instructors. This empirical study addresses this by answering the following questions: First, are statistical misconceptions pervasive among academics with a special interest in business research methods? If so, second, is there an association between the pervasiveness of statistical misconceptions and the preferred research tradition (qualitative, quantitative, mixed methods)?. Data were collected via a web questionnaire from a purposive sample of academics with an expressed interest in business research methods. The questionnaire comprised 30 categorical statements (agree, disagree, don't know) focusing on statistical misconceptions (and conceptions) relating to descriptive statistics, design strategies, inferential statistics and regression, and five demographic questions. We targeted a critical case purposive sample of 679 potential respondents. Although 166 consented to take part, only 80 completed the questionnaire and their responses form the basis of the statistical analysis, a response rate of 11.8 %. The study provides empirical evidence of both an absence of knowledge and a high pervasiveness of faulty notions that have infected the thinking of academics relating to both research design and the use of statistics. This is particularly so for academics who prefer quantitative methods, those preferring qualitative methods being more likely to admit that they do not know. The study argues that such lack of knowledge and misconceptions reduce the true utility of statistics in research. Recommendations are offered regarding the teaching of statistics within business research methods.peer-reviewe
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