2,854 research outputs found

    Role of quantum nuclei and local fields in the x-ray absorption spectra of water and ice

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    We calculate the x-ray absorption spectra of liquid water at ambient conditions and of hexagonal ice close to melting, using a static GW approach that includes approximately local field effects. Quantum dynamics of the nuclei is taken into account by averaging the absorption cross section over molecular configurations generated by path integral simulations. We find that inclusion of quantum disorder is essential to bring the calculated spectra in close agreement with experiment. In particular, the intensity of the pre-edge feature, a spectral signature of broken and distorted hydrogen bonds, is accurately reproduced, in water and ice, only when quantum nuclei are considered. The effect of the local fields is less important but non negligible, particularly in ice

    Using information to deliver safer care: a mixed-methods study exploring general practitioners’ information needs in North West London primary care

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    The National Health Service in England has given increasing priority to improving inter-professional communication, enabling better management of patients with chronic conditions and reducing medical errors through effective use of information. Despite considerable efforts to reduce patient harm through better information usage, medical errors continue to occur, posing a serious threat to patient safety.This study explores the range, quality and sophistication of existing information systems in primary care with the aim to capture what information practitioners need to provide a safe service and identify barriers to its effective use in care pathways.Data were collected through semi-structured interviews with general practitioners from surgeries in North West London and a survey evaluating their experience with information systems in care pathways.Important information is still missing, specifically discharge summaries detailing medication changes and changes in the diagnosis and management of patients, blood results ordered by hospital specialists and findings from clinical investigations. Participants identified numerous barriers, including the communication gap between primary and secondary care, the variable quality and consistency of clinical correspondence and the inadequate technological integration.Despite attempts to improve integration and information flow in care pathways, existing systems provide practitioners with only partial access to information, hindering their ability to take informed decisions. This study offers a framework for understanding what tools should be in place to enable effective use of information in primary care

    An attributional analysis of goal setting, acceptance, and performance outcome on supervisor\u27s evaluations

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    Previous research investigated the effect of goal setting on supervisors\u27 evaluations of employee performance and the causes attributed to that performance. The results demonstrated that attributions for performance were more a ffected by success versus failure in the assigned than in the participative or self-set condition . It was hypothesized that a possible exception to this relationship might occur when the goal was not accepted by the employee. This 3 x 2 x 2 factorial design investigated the impact of goal acceptance on ratings of task performance and attributions concerning that performance. The overriding determinant of attributions regarding the employee was whether or not the goal was met. For instance, whether the employee succeeded appeared to be the overriding determinant in perception of goal commitment, luck, ability , goal difficulty , and effort in both the accept and reject conditions. In addition, the accept/reject manipulation revealed some other important implications for supervisory performance appraisals and causal attribution ratings . When the employee failed in meeting the goal, supervisors (subjects) rated the employee who accepted the goal as performing better than the employee who failed but rejected the goal

    Development of the CHARIOT Research Register for the Prevention of Alzheimer’s Dementia and Other Late Onset Neurodegenerative Diseases

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    Identifying cognitively healthy people at high risk of developing dementia is an ever-increasing focus. These individuals are essential for inclusion in observational studies into the natural history of the prodromal and early disease stages and for interventional studies aimed at prevention or disease modification. The success of this research is dependent on having access to a well characterised, representative and sufficiently large population of individuals. Access to such a population remains challenging as clinical research has, historically, focussed on patients with dementia referred to secondary and tertiary services. The primary care system in the United Kingdom allows access to a true prodromal population prior to symptoms emerging and specialist referral. We report the development and recruitment rates of the CHARIOT register, a primary care-based recruitment register for research into the prevention of dementia. The CHARIOT register was designed specifically to support recruitment into observational natural history studies of pre-symptomatic or prodromal dementia stages, and primary or secondary prevention pharmaceutical trials or other prevention strategies for dementia and other cognitive problems associated with ageing.Participants were recruited through searches of general practice lists across the west and central London regions. Invitations were posted to individuals aged between 60 and 85 years, without a diagnosis of dementia. Upon consent, a minimum data set of demographic and contact details was extracted from the patient's electronic health record.To date, 123 surgeries participated in the register, recruiting a total of 24,509 participants-a response rate of 22.3%. The age, gender and ethnicity profiles of participants closely match that of the overall eligible population. Higher response rates tended to be associated with larger practices (r = 0.34), practices with a larger older population (r = 0.27), less socioeconomically disadvantaged practices (r = 0.68), and practices with a higher proportion of White patients (r = 0.82).Response rates are comparable to other registers reported in the literature, and indicate good interest and support for a research register and for participation in research for the prevention of age-related neurodegenerative diseases and dementia. We consider that the simplicity of the approach means that this system is easily scalable and replicable across the UK and internationally

    Unifying Requirements and Code: an Example

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    Requirements and code, in conventional software engineering wisdom, belong to entirely different worlds. Is it possible to unify these two worlds? A unified framework could help make software easier to change and reuse. To explore the feasibility of such an approach, the case study reported here takes a classic example from the requirements engineering literature and describes it using a programming language framework to express both domain and machine properties. The paper describes the solution, discusses its benefits and limitations, and assesses its scalability.Comment: 13 pages; 7 figures; to appear in Ershov Informatics Conference, PSI, Kazan, Russia (LNCS), 201

    Optical study of the anisotropic erbium spin flip-flop dynamics

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    We investigate the erbium flip-flop dynamics as a limiting factor of the electron spin lifetime and more generally as an indirect source of decoherence in rare-earth doped insulators. Despite the random isotropic arrangement of dopants in the host crystal, the dipolar interaction strongly depends on the magnetic field orientation following the strong anisotropy of the gg-factor. In Er3+^{3+}:Y2_2SiO5_5, we observe by transient optical spectroscopy a three orders of magnitude variation of the erbium flip-flop rate (10ppm dopant concentration). The measurements in two different samples, with 10ppm and 50ppm concentrations, are well-supported by our analytic modeling of the dipolar coupling between identical spins with an anisotropic gg-tensor. The model can be applied to other rare-earth doped materials. We extrapolate the calculation to Er3+^{3+}:CaWO4_4, Er3+^{3+}:LiNbO3_3 and Nd3+^{3+}:Y2_2SiO5_5 at different concentrations
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