2,515 research outputs found

    Entanglement and its Role in Shor's Algorithm

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    Entanglement has been termed a critical resource for quantum information processing and is thought to be the reason that certain quantum algorithms, such as Shor's factoring algorithm, can achieve exponentially better performance than their classical counterparts. The nature of this resource is still not fully understood: here we use numerical simulation to investigate how entanglement between register qubits varies as Shor's algorithm is run on a quantum computer. The shifting patterns in the entanglement are found to relate to the choice of basis for the quantum Fourier transform.Comment: 15 pages, 4 eps figures, v1-3 were for conference proceedings (not included in the end); v4 is improved following referee comments, expanded explanations and added reference

    Predictive sensor method and apparatus

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    A microprocessor and electronics package employing predictive methodology was developed to accelerate the response time of slowly responding hydrogen sensors. The system developed improved sensor response time from approximately 90 seconds to 8.5 seconds. The microprocessor works in real-time providing accurate hydrogen concentration corrected for fluctuations in sensor output resulting from changes in atmospheric pressure and temperature. Following the successful development of the hydrogen sensor system, the system and predictive methodology was adapted to a commercial medical thermometer probe. Results of the experiment indicate that, with some customization of hardware and software, response time improvements are possible for medical thermometers as well as other slowly responding sensors

    Digital data registration and differencing compression system

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    A process is disclosed for x ray registration and differencing which results in more efficient compression. Differencing of registered modeled subject image with a modeled reference image forms a differenced image for compression with conventional compression algorithms. Obtention of a modeled reference image includes modeling a relatively unrelated standard reference image upon a three-dimensional model, which three-dimensional model is also used to model the subject image for obtaining the modeled subject image. The registration process of the modeled subject image and modeled reference image translationally correlates such modeled images for resulting correlation thereof in spatial and spectral dimensions. Prior to compression, a portion of the image falling outside a designated area of interest may be eliminated, for subsequent replenishment with a standard reference image. The compressed differenced image may be subsequently transmitted and/or stored, for subsequent decompression and addition to a standard reference image so as to form a reconstituted or approximated subject image at either a remote location and/or at a later moment in time. Overall effective compression ratios of 100:1 are possible for thoracic x ray digital images

    Structure of fish assemblages on coastal rocky shores of the Azores

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    Bol. Mus. Mun. Funchal, Sup. N.Âș 6: 127-138, 2001The structure of fish assemblages was investigated from the surface down to 25 m depth on Azorean rocky shores. A total of 57 fish species was recorded by visual censuses, most species (66%) occurring in the whole depth range studied. Fish abundance was dominated by 11 species, mainly sparids, labrids, carangids and pomacentrids, which constituted over 88% of the total number of individuals recorded. The trophic structure of the fish assemblages studied in the Azores was characterized by the dominance of benthic mesocarnivores and high proportions of herbivores and pelagic macrocarnivores.A estrutura das comunidades ictiolĂłgicas dos fundos rochosos dos Açores foi estudada desde a superfĂ­cie atĂ© aos 25 m de profundidade. Um total de 57 espĂ©cies de peixes foi identificado com recurso a censos visuais. A maioria das espĂ©cies (66%) ocorreu em toda a gama de profundidades estudada. A fauna ictiolĂłgica era dominada, em termos de abundĂąncia, por 11 espĂ©cies, principalmente pertencentes Ă s famĂ­lias Sparidae, Labridae, Carangidae e Pomacentridae, os quais constituĂ­ram mais de 88% do nĂșmero total de indivĂ­duos observados. A estrutura trĂłfica das comunidades ictiolĂłgicas estudadas nos Açores apresentouse dominada por meso-carnĂ­voros bentĂłnicos e proporçÔes elevadas de herbĂ­voros e macro-carnĂ­voros pelĂĄgico

    You don't know what's around the corner: A qualitative study of professional footballers in England facing career-transition

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    Career transition in sport is a rapidly growing area within the field of sport psychology. Interest in this area has been fuelled by the need for an increased number of professional athletes seeking support and assistance during transition from sport. However, whilst research in this field has focused in on a wide range of sports, specific research on retirement in professional football has been limited. Because of this it is argued that current research may fail to consider specific issues associated with the transition from professional football. Therefore, in an attempt to add to the existing body of research the current study aimed to provide an in-depth insight into how professional footballers understand their ‘lived-world’ during exit from their sport. A total of eight former professional footballers, who were at the time experiencing the possibility of career-transition, were interviewed in two separate focus group discussions. The interviews were analysed using interpretive phenomenological analysis (IPA). The key findings from the research show that a lack of control over their lives, lack of pre-planning and preparation for retirement as well as support and ability to seek it led professional footballers to experience heightened levels of anxiety, uncertainty and fear for their futures as well as an unexpected sense of rejection during career transition. These findings have implications for support organisations and those interested in the life-long welfare of professional footballers. It is proposed that an emphasis on pre-planning and preparation, provisions of support and encouraging help-seeking may aid professional footballers during the process out of their sport

    A non-grey analytical model for irradiated atmospheres. II: Analytical vs. numerical solutions

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    The recent discovery and characterization of the diversity of the atmospheres of exoplanets and brown dwarfs calls for the development of fast and accurate analytical models. We quantify the accuracy of the analytical solution derived in paper I for an irradiated, non-grey atmosphere by comparing it to a state-of-the-art radiative transfer model. Then, using a grid of numerical models, we calibrate the different coefficients of our analytical model for irradiated solar-composition atmospheres of giant exoplanets and brown dwarfs. We show that the so-called Eddington approximation used to solve the angular dependency of the radiation field leads to relative errors of up to 5% on the temperature profile. We show that for realistic non-grey planetary atmospheres, the presence of a convective zone that extends to optical depths smaller than unity can lead to changes in the radiative temperature profile on the order of 20% or more. When the convective zone is located at deeper levels (such as for strongly irradiated hot Jupiters), its effect on the radiative atmosphere is smaller. We show that the temperature inversion induced by a strong absorber in the optical, such as TiO or VO is mainly due to non-grey thermal effects reducing the ability of the upper atmosphere to cool down rather than an enhanced absorption of the stellar light as previously thought. Finally, we provide a functional form for the coefficients of our analytical model for solar-composition giant exoplanets and brown dwarfs. This leads to fully analytical pressure-temperature profiles for irradiated atmospheres with a relative accuracy better than 10% for gravities between 2.5m/s^2 and 250 m/s^2 and effective temperatures between 100 K and 3000 K. This is a great improvement over the commonly used Eddington boundary condition.Comment: Accepted in A&A, models are available at http://www.oca.eu/parmentier/nongrey or in CD

    The effect of symmetry breaking on the dynamics near a structurally stable heteroclinic cycle between equilibria and a periodic orbit

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    The effect of small forced symmetry breaking on the dynamics near a structurally stable heteroclinic cycle connecting two equilibria and a periodic orbit is investigated. This type of system is known to exhibit complicated, possibly chaotic dynamics including irregular switching of sign of various phase space variables, but details of the mechanisms underlying the complicated dynamics have not previously been investigated. We identify global bifurcations that induce the onset of chaotic dynamics and switching near a heteroclinic cycle of this type, and by construction and analysis of approximate return maps, locate the global bifurcations in parameter space. We find there is a threshold in the size of certain symmetry-breaking terms below which there can be no persistent switching. Our results are illustrated by a numerical example

    SVA retrotransposons as modulators of gene expression.

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    Endogenous mobile genetic elements can give rise to de novo germline or somatic mutations that can have dramatic consequences for genome regulation both local and possibly more globally based on the site of integration. However if we consider them as "normal genetic" components of the reference genome then they are likely to modify local chromatin structure which would have an effect on gene regulation irrelevant of their ability to further transpose. As such they can be treated as any other domain involved in a gene × environment interaction. Similarly their evolutionary appearance in the reference genome would supply a driver for species specific responses/traits. Our recent data would suggest the hominid specific subset of retrotransposons, SINE-VNTR-Alu (SVA), can function as transcriptional regulatory domains both in vivo and in vitro when analyzed in reporter gene constructs. Of particular interest in the SVA element, were the variable number tandem repeat (VNTR) domains which as their name suggests can be polymorphic. We and others have previously shown that VNTRs can be both differential regulators and biomarkers of disease based on the genotype of the repeat. Here, we provide an overview of why polymorphism in the SVA elements, in particular the VNTRs, could alter gene expression patterns that could be mechanistically associated with different traits in evolution or disease progression in humans

    Flexible and adaptable hospitals – Australian case studies

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    In 2009, a literature review uncovered different international approaches to achieving flexible and adaptable health facilities and concluded by recommending further research focussing on Australian hospitals to identify key site issues, design features, and major upgrades that have influenced longer term responses to changing modes of service delivery and other demands in local settings. Responding to these recommendations, this second stage research was conducted by reviewing further relevant literature and project documentation for five case studies, visiting and documenting key adaptability features of each case study facility and consulting with health facility personnel where available. Findings include that longer-term flexibility is assisted by: generous site area, lower rise hospital buildings along a horizontal circulation spine (‗hospital street‘), surplus building services capacity facilitating easy expansion/alteration, and a consistent workable planning grid supporting a range of standardised room sizes. Future investigation should consider the impact of high land values on site utilisation especially in terms of future proofing multi-storey buildings, and how to assist health clients decide when ‗enough‘ flexibility has been provided
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