3,280 research outputs found

    Parallelism for Quantum Computation with Qudits

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    Robust quantum computation with d-level quantum systems (qudits) poses two requirements: fast, parallel quantum gates and high fidelity two-qudit gates. We first describe how to implement parallel single qudit operations. It is by now well known that any single-qudit unitary can be decomposed into a sequence of Givens rotations on two-dimensional subspaces of the qudit state space. Using a coupling graph to represent physically allowed couplings between pairs of qudit states, we then show that the logical depth of the parallel gate sequence is equal to the height of an associated tree. The implementation of a given unitary can then optimize the tradeoff between gate time and resources used. These ideas are illustrated for qudits encoded in the ground hyperfine states of the atomic alkalies 87^{87}Rb and 133^{133}Cs. Second, we provide a protocol for implementing parallelized non-local two-qudit gates using the assistance of entangled qubit pairs. Because the entangled qubits can be prepared non-deterministically, this offers the possibility of high fidelity two-qudit gates.Comment: 9 pages, 3 figure

    Bounds on R-parity violating supersymmetric couplings from leptonic and semi-leptonic meson decays

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    We present a comprehensive update of the bounds on R-Parity violating supersymmetric couplings from lepton-flavour- and lepton-number-violating decay processes. We consider tau and mu decays as well as leptonic and semi-leptonic decays of mesons. We present several new bounds resulting from tau, eta and Kaon decays and correct some results in the literature concerning B-meson decays.Comment: 30 pages; changed title, updated some bounds from the literature from different references, added reference

    The Design, Construction and Commissioning of a Small Scale Dynamic Calibrated Hot Box (CHB)

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    Sustainable construction and in particular the sustainability of materials is a global issue with legislation on material properties and product performance at the forefront. In traditional constructed buildings however, it can be extremely challenging to get accurate data on performance. The variability of building materials design, manufacture and construction from different eras is substantial, even within local areas due to the vernacular nature of construction from these periods. Material properties testing can be expensive and is not always readily available when required and is therefore often ignored, particularly in the retrofitting of historic buildings. This can have major adverse effects on the building fabric and for its inhabitant’s health if the appropriate material interventions are not chosen. An inexpensive environmental chamber for testing such materials has been designed and built at the Dublin Institute of Technology, (DIT) Ireland, adopting comparable standards from EN ISO 8990 and ASTM C1363. This paper describes the design requirements for the construction of an affordable and mobile calibrated hot box (CHB) for the testing of historic materials. A characterisation panel has been used to carry out early calibration testing and the results of this are discussed. Improvements and tweaking of the first test are also discussed

    Communication of genetic information within families: the case for familial comity

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    Advances in genetic technologies raise a multitude of ethical issues, some of which give rise to novel dilemmas for medical practice. One of the most controversial problems arising in clinical genetics is that of confidentiality and who may disclose genetic health information. This paper considers the question of when it is appropriate for health professionals to disclose clinically significant genetic information without patient consent. Existing ethical principles offer little guidance in relation to this issue. We build on suggestions that genetic information may be viewed as collective or shared information, and we introduce the concept of ‘familial comity’ as a fresh way to consider the issues. Keywords: Genetics, Ethics, clinical, Confidentiality, Family, Genetic privacyThis article was written by Dr Ainsley Newson during the time of her employment with the University of Bristol, UK (2006-2012). Self-archived in the Sydney eScholarship Repository with permission of Bristol University, Sept 2014

    Communication of genetic information within families: the case for familial comity

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    Advances in genetic technologies raise a multitude of ethical issues, some of which give rise to novel dilemmas for medical practice. One of the most controversial problems arising in clinical genetics is that of confidentiality and who may disclose genetic health information. This paper considers the question of when it is appropriate for health professionals to disclose clinically significant genetic information without patient consent. Existing ethical principles offer little guidance in relation to this issue. We build on suggestions that genetic information may be viewed as collective or shared information, and we introduce the concept of ‘familial comity’ as a fresh way to consider the issues. Keywords: Genetics, Ethics, clinical, Confidentiality, Family, Genetic privacyThis article was written by Dr Ainsley Newson during the time of her employment with the University of Bristol, UK (2006-2012). Self-archived in the Sydney eScholarship Repository with permission of Bristol University, Sept 2014

    Isobaric multiplet yrast energies and isospin non-conserving forces

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    The isovector and isotensor energy differences between yrast states of isobaric multiplets in the lower half of the pfpf region are quantitatively reproduced in a shell model context. The isospin non-conserving nuclear interactions are found to be at least as important as the Coulomb potential. Their isovector and isotensor channels are dominated by J=2 and J=0 pairing terms, respectively. The results are sensitive to the radii of the states, whose evolution along the yrast band can be accurately followed.Comment: 4 pages, 4 figures. Superseeds second part of nucl-th/010404

    Time scales and modes of reef lagoon infilling in the Maldives and controls on the onset of reef island formation

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    Faro are annular reefs, with reef flats near sea level and lagoons of variable depth, characteristic of both the perimeter and lagoons of Maldivian (Indian Ocean) atolls. Their geomorphic development remains largely unknown, but where faro lagoons (termed velu in Maldivian) have infilled and support reef islands, these provide precious habitable land. Understanding the timing and modes of velu infilling is thus directly relevant to questions about reef island development and vulnerability. Here we use a chronostratigraphic data set obtained from a range of atoll-interior faro with partially to fully filled velu (including those with reef islands) from Baa (South Maalhosmadulu) Atoll, Maldives, to determine time scales and modes of velu infilling, and to identify the temporal and spatial thresholds that control reef island formation. Our data suggest a systematic relationship between faro size, velu infilling, and island development. These relationships likely vary between atolls as a function of atoll lagoon depth, but in Baa Atoll, our data set indicates the following faro-size relationships exist: (1) faros <∼0.5 km2 have velu that were completely infilled by ca. 3000 calibrated years B.P. (cal yr B.P.) with islands having established on these deposits by ca. 2.5 cal kyr B.P.; (2) faros >0.5 km2 but <∼1.25 km2 have velu in late stages of infill, may support unvegetated sand cays and, given sufficient sand supply, may evolve into larger, more permanent islands; and (3) faros >∼1.25 km2 have unfilled (deeper) velu which might only infill over long time scales and which are thus unlikely to support new island initiation. These new observations, when combined with previously published data on Maldivian reef island development, suggest that while the velu of the largest faro are unlikely to fill over the next few centuries (at least), other faro with near-infilled velu may provide important foci for future reef-island building, even under present highstand (and slightly rising) sea levels

    Glucose and lipopolysaccharide regulate proatherogenic cytokine release from mononuclear cells in polycystic ovary syndrome

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    Women with polycystic ovary syndrome (PCOS) have chronic low-grade inflammation, which can increase the risk of atherogenesis. We examined the effect of glucose ingestion and lipopolysaccharide (LPS) on markers of proatherogenic inflammation in the mononuclear cells (MNC) and plasma of women with PCOS. Sixteen women with PCOS (8 lean, 8 obese) and 15 weight-matched controls (8 lean, 7 obese) underwent a 3-h oral glucose tolerance test (OGTT). Interleukin-6 (IL-6) and interleukin-1β (IL-1β) release from MNC cultured in the presence of LPS and plasma IL-6, C-reactive protein (CRP), and soluble vascular adhesion molecule-1 (sVCAM-1) were measured from blood samples drawn while fasting and 2 h after glucose ingestion. Truncal fat was measured by dual-energy absorptiometry (DEXA). Lean women with PCOS and obese controls failed to suppress LPS-stimulated IL-6 and IL-1β release from MNC after glucose ingestion. In contrast, obese women with PCOS suppressed these MNC-derived cytokines under the same conditions. In response to glucose ingestion, plasma IL-6 and sVCAM-1 increased and CRP suppression was attenuated in both PCOS groups and obese controls compared with lean controls. Fasting plasma IL-6 and CRP correlated positively with percentage of truncal fat. The absolute change in plasma IL-6 correlated positively with testosterone. We conclude that glucose ingestion promotes proatherogenic inflammation in PCOS with a systemic response that is independent of obesity. Based on the suppressed MNC-derived cytokine responses suggestive of LPS tolerance, chronic low-grade inflammation may be more profound in obese women with PCOS. Excess abdominal adiposity and hyperandrogenism may contribute to atherogenesis in PCOS
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