489 research outputs found

    Quantum Computing with NMR

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    A review of progress in NMR quantum computing and a brief survey of the literatureComment: Commissioned by Progress in NMR Spectroscopy (95 pages, no figures

    A retrospective on the VAX VMM security kernel

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    Mentoring student nurses and the educational use of self: A hermeneutic phenomenological study

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    Background In the United Kingdom, pre-registration nurse education relies on workplace mentors to support and assess practice learning. Despite research to clarify expectations and develop support structures, mentors nevertheless report being overwhelmed by the responsibility of mentoring alongside their clinical work. Understanding of their lived experience appears limited. Objectives The aim of the study was to achieve a deeper understanding of the lived experience of mentoring, searching for insights into how mentors can be better prepared and supported. Design The mentor lifeworld was explored utilizing a hermeneutic phenomenological methodology drawing on Heidegger. Settings and Participants Twelve mentors, who worked in a range of clinical settings in England were recruited via purposive and snowball sampling. Method Participants described their experiences of mentoring through in-depth interviews and event diaries which included ‘rich pictures’. Analysis involved the application of four lifeworld existentials proposed by van Manen — temporality, spatiality, corporeality and relationality. Findings The essence of being a mentor was ‘the educational use of self’. Temporality featured in the past self and moving with daily/work rhythms. Spatiality evoked issues of proximity and accountability and the inner and outer spaces of patients' bodies. Mentor corporeality revealed using the body for teaching, and mentors revealed their relationality in providing a ‘good educational experience’ and sustaining their ‘educational selves’. Conclusions ‘The educational use of self’ offers insight into the lived experience of mentors, and exposes the potentially hidden elements of mentoring experience, which can inform mentor preparation and support

    The Role of Oestrogen Receptor Beta (ERÎČ) in the Aetiology and Treatment of Type 2 Diabetes Mellitus

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    Introduction: Challenges facing the treatment of type 2 diabetes necessitate the search for agents which act via alternative pathways to provide better therapeutic outcomes. Recently, an increasing body of evidence implicates the activation of oestrogen receptors (ERα and ERÎČ) in the development and treatment of underlying conditions in type 2 diabetes. This article summarizes available evidence for the involvement of oestrogen receptors in insulin secretion, insulin resistance as well as glucose uptake and highlights the potential of ERÎČ as a therapeutic target. Background: Recent studies indicate an association between the activation of each of the isoforms of ER and recent findings indicate that ERÎČ shows promise as a potential target for antidiabetic drugs. In vitro and in vivo studies in receptor knockout mice indicate beneficial actions of selective agonists of ERÎČ receptor and underscore its therapeutic potential. Conclusion: Studies are needed to further elucidate the exact mechanism underlying the role of ERÎČ activation as a therapeutic approach in the management of type 2 diabetes

    LSST: from Science Drivers to Reference Design and Anticipated Data Products

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    (Abridged) We describe here the most ambitious survey currently planned in the optical, the Large Synoptic Survey Telescope (LSST). A vast array of science will be enabled by a single wide-deep-fast sky survey, and LSST will have unique survey capability in the faint time domain. The LSST design is driven by four main science themes: probing dark energy and dark matter, taking an inventory of the Solar System, exploring the transient optical sky, and mapping the Milky Way. LSST will be a wide-field ground-based system sited at Cerro Pach\'{o}n in northern Chile. The telescope will have an 8.4 m (6.5 m effective) primary mirror, a 9.6 deg2^2 field of view, and a 3.2 Gigapixel camera. The standard observing sequence will consist of pairs of 15-second exposures in a given field, with two such visits in each pointing in a given night. With these repeats, the LSST system is capable of imaging about 10,000 square degrees of sky in a single filter in three nights. The typical 5σ\sigma point-source depth in a single visit in rr will be ∌24.5\sim 24.5 (AB). The project is in the construction phase and will begin regular survey operations by 2022. The survey area will be contained within 30,000 deg2^2 with ÎŽ<+34.5∘\delta<+34.5^\circ, and will be imaged multiple times in six bands, ugrizyugrizy, covering the wavelength range 320--1050 nm. About 90\% of the observing time will be devoted to a deep-wide-fast survey mode which will uniformly observe a 18,000 deg2^2 region about 800 times (summed over all six bands) during the anticipated 10 years of operations, and yield a coadded map to r∌27.5r\sim27.5. The remaining 10\% of the observing time will be allocated to projects such as a Very Deep and Fast time domain survey. The goal is to make LSST data products, including a relational database of about 32 trillion observations of 40 billion objects, available to the public and scientists around the world.Comment: 57 pages, 32 color figures, version with high-resolution figures available from https://www.lsst.org/overvie

    A generalized frequency detuning method for multidegree-of-freedom oscillators with nonlinear stiffness

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    In this paper, we derive a frequency detuning method for multi-degree-of-freedom oscillators with nonlinear stiffness. This approach includes a matrix of detuning parameters, which are used to model the amplitude dependent variation in resonant frequencies for the system. As a result, we compare three different approximations for modeling the affect of the nonlinear stiffness on the linearized frequency of the system. In each case, the response of the primary resonances can be captured with the same level of accuracy. However, harmonic and subharmonic responses away from the primary response are captured with significant differences in accuracy. The detuning analysis is carried out using a normal form technique, and the analytical results are compared with numerical simulations of the response. Two examples are considered, the second of which is a two degree-of-freedom oscillator with cubic stiffnesses

    Novel genetic loci associated with hippocampal volume

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    The hippocampal formation is a brain structure integrally involved in episodic memory, spatial navigation, cognition and stress responsiveness. Structural abnormalities in hippocampal volume and shape are found in several common neuropsychiatric disorders. To identify the genetic underpinnings of hippocampal structure here we perform a genome-wide association study (GWAS) of 33,536 individuals and discover six independent loci significantly associated with hippocampal volume, four of them novel. Of the novel loci, three lie within genes (ASTN2, DPP4 and MAST4) and one is found 200 kb upstream of SHH. A hippocampal subfield analysis shows that a locus within the MSRB3 gene shows evidence of a localized effect along the dentate gyrus, subiculum, CA1 and fissure. Further, we show that genetic variants associated with decreased hippocampal volume are also associated with increased risk for Alzheimer's disease (rg =-0.155). Our findings suggest novel biological pathways through which human genetic variation influences hippocampal volume and risk for neuropsychiatric illness

    Integrating sequence and array data to create an improved 1000 Genomes Project haplotype reference panel

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    A major use of the 1000 Genomes Project (1000GP) data is genotype imputation in genome-wide association studies (GWAS). Here we develop a method to estimate haplotypes from low-coverage sequencing data that can take advantage of single-nucleotide polymorphism (SNP) microarray genotypes on the same samples. First the SNP array data are phased to build a backbone (or 'scaffold') of haplotypes across each chromosome. We then phase the sequence data 'onto' this haplotype scaffold. This approach can take advantage of relatedness between sequenced and non-sequenced samples to improve accuracy. We use this method to create a new 1000GP haplotype reference set for use by the human genetic community. Using a set of validation genotypes at SNP and bi-allelic indels we show that these haplotypes have lower genotype discordance and improved imputation performance into downstream GWAS samples, especially at low-frequency variants. © 2014 Macmillan Publishers Limited. All rights reserved
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