13,345 research outputs found

    The Inclusive-Exclusive Connection and the Neutron Negative Central Charge Density

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    We find an interpretation of the recent finding that the central charge density of the neutron is negative by using models of generalized parton distributions at zero skewness to relate the behavior of deep inelastic scattering quark distributions, evaluated at large values of Bjorken x, to the transverse charge density evaluated at small distances. The key physical input of these models is the Drell-Yan-West relation We find that the d quarks dominate the neutron structure function for large values of Bjorken x, where the large longitudinal momentum of the struck quark has a significant impact on determining the center-of-momentum of the system, and thus the "center" of the nucleon in the transverse position plane.Comment: 17 pages, 8 figures. Text of an invited talk presented by G. A. Miller at the 2008 Division of Nuclear Physics Meeting in Oakland. Prepared for Int. Journ. Mod. Phys.

    A Third Planet Orbiting HIP 14810

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    We present new precision radial velocities and a three-planet Keplerian orbit fit for the V = 8.5, G5 V star HIP 14810. We began observing this star at Keck Observatory as part of the N2K Planet Search Project. Wright et al. (2007) announced the inner two planets to this system, and subsequent observations have revealed the outer planet planet and the proper orbital solution for the middle planet. The planets have minimum masses of 3.9, 1.3, and 0.6 M_Jup and orbital periods of 6.67, 147.7, and 952 d, respectively. We have numerically integrated the family of orbital solutions consistent with the data and find that they are stable for at least 10^6 yr. Our photometric search shows that the inner planet does not transit.Comment: ApJL, accepte

    Adherence to UK national guidance for discharge information: an audit in primary care

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    Aims: Poor communication of clinical information between healthcare settings is associated with patient harm. In 2008, the UK National Prescribing Centre (NPC) issued guidance regarding the minimum information to be communicated upon hospital discharge. This study evaluates the extent of adherence to this guidance and identifies predictors of adherence. Methods: This was an audit of discharge summaries received by medical practices in one UK primary care trust of patients hospitalized for 24 h or longer. Each discharge summary was scored against the applicable NPC criteria which were organized into: ‘patient, admission and discharge’, ‘medicine’ and ‘therapy change’ information. Results: Of 3444 discharge summaries audited, 2421 (70.3%) were from two teaching hospitals and 906 (26.3%) from three district hospitals. Unplanned admissions accounted for 2168 (63.0%) of the audit sample and 74.6% (2570) of discharge summaries were electronic. Mean (95% CI) adherence to the total NPC minimum dataset was 71.7% [70.2, 73.2]. Adherence to patient, admission and discharge information was 77.3% (95% CI 77.0, 77.7), 67.2% (95% CI 66.3, 68.2) for medicine information and 48.9% (95% CI 47.5, 50.3) for therapy change information. Allergy status, co-morbidities, medication history and rationale for therapy change were the most frequent omissions. Predictors of adherence included quality of the discharge template, electronic discharge summaries and smaller numbers of prescribed medicines. Conclusions: Despite clear guidance regarding the content of discharge information, omissions are frequent. Adherence to the NPC minimum dataset might be improved by using comprehensive electronic discharge templates and implementation of effective medicines reconciliation at both sides of the health interface

    Evolving librarian participation in a specialized primary care medical education program

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    Objectives: To describe the extent to which health sciences librarians are embedded into a program that gives medical students focused experiences in underserved international, rural, or inner city primary care settings. Methods: Since 2009, librarians at a large urban research university have worked with a longitudinal program that gives medical students focused education and experience in underserved international, rural, or inner city primary care settings. Initially, the library offered a meeting space for the program and librarians led a class on library resources prior to students beginning work on a required capstone projects. Librarians cultivated relationships with faculty and students through interactions in classes and in individual consultations. As the program matured and its needs changed, librarians offered services and expertise to match the growth of the curriculum. Results: Librarians currently co-teach two capstone training sessions for third year medical students, which has progressed from a basic orientation on library resources and searching to in-depth instructions on literature reviews and leading small group discussions on student capstone projects. As a result of these sessions, librarians hold regular consultations with students at various stages of the projects to train them in library resources and assist them in conducting literature reviews. A librarian also met with faculty to revise, and subsequently co-teach, a journal club for first and second year students focusing on issues health care in underserved populations and critical appraisal of research literature. More recently, a librarian was asked to serve as part of an interdisciplinary panel that reviews student capstone project proposals. Conclusions: Over the past several years, librarians have taken on increasingly complex roles in a small specialized program within a school of medicine. Through regular contact with faculty and students and a willingness to participate at any level of the program, librarians have moved well past teaching one-shot sessions to being fully embedded in the program

    Searching for Earth-mass planets around α\alpha Centauri: precise radial velocities from contaminated spectra

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    This work is part of an ongoing project which aims to detect terrestrial planets in our neighbouring star system α\alpha Centauri using the Doppler method. Owing to the small angular separation between the two components of the α\alpha Cen AB binary system, the observations will to some extent be contaminated with light coming from the other star. We are accurately determining the amount of contamination for every observation by measuring the relative strengths of the H-α\alpha and NaD lines. Furthermore, we have developed a modified version of a well established Doppler code that is modelling the observations using two stellar templates simultaneously. With this method we can significantly reduce the scatter of the radial velocity measurements due to spectral cross-contamination and hence increase our chances of detecting the tiny signature caused by potential Earth-mass planets. After correcting for the contamination we achieve radial velocity precision of ∼2.5 m s−1\sim 2.5\,\mathrm{m\,s^{-1}} for a given night of observations. We have also applied this new Doppler code to four southern double-lined spectroscopic binary systems (HR159, HR913, HR7578, HD181958) and have successfully recovered radial velocities for both components simultaneously.Comment: accepted for publication in the International Journal of Astrobiology (published by Cambridge University Press); will appear in a revised form, subsequent to editorial input by Cambridge University Pres

    Fabricating and using a micromachined magnetostatic relay or switch

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    A micromachined magnetostatic relay or switch includes a springing beam on which a magnetic actuation plate is formed. The springing beam also includes an electrically conductive contact. In the presence of a magnetic field, the magnetic material causes the springing beam to bend, moving the electrically conductive contact either toward or away from another contact, and thus creating either an electrical short-circuit or an electrical open-circuit. The switch is fabricated from silicon substrates and is particularly useful in forming a MEMs commutation and control circuit for a miniaturized DC motor

    Interaction of staphylococci with bone

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    AbstractStaphylococci, in particular Staphylococcus aureus, are the predominant cause of bone infections worldwide. These infections are painful, debilitating and with the rise in antibiotic-resistant forms, increasingly difficult to treat. The growth in the number of prosthetic joint replacement procedures also provides new opportunities for these infections to take hold. Comprehending the mechanisms by which staphylococci interact with and damage bone is critical to the development of new approaches to meet this challenge. This review summarises current understanding of the mechanisms by which staphylococci infect and damage bone. We address the role of the inflammatory response to staphylococcal infection in disrupting the homeostatic balance of bone matrix deposition and resorption and thereby mediating bone destruction. A number of virulence factors that have been shown to contribute to bone infection and pathology are discussed, however no single factor has been defined as being specific to bone infections. Although traditionally considered an extracellular pathogen, there is increasing evidence that staphylococci are able to invade host cells, and that an intracellular lifestyle may facilitate long-term persistence in bone tissue, enabling evasion of antimicrobials and host immune responses. ‘Small colony variant’ strains, with mutations disabling the electron transport pathway appear particularly adept at invading and persisting within host cells, and exhibit enhanced antimicrobial resistance, and may represent a further complication in the treatment and management of staphylococcal bone disease
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