78 research outputs found

    Embedding Branes in Flat Two-time Spaces

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    We show how non-near horizon, non-dilatonic pp-brane theories can be obtained from two embedding constraints in a flat higher dimensional space with 2 time directions. In particular this includes the construction of D3 branes from a flat 12-dimensional action, and M2 and M5 branes from 13 dimensions. The worldvolume actions are found in terms of fields defined in the embedding space, with the constraints enforced by Lagrange multipliers.Comment: LaTex, 8 pages. Contribution to the TMR Conference on Quantum aspects of gauge theories, supersymmetry and unification. Paris, 1-7 September 199

    Are white matter lesions directly associated with cognitive impairment in patients with lacunar infarcts?

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    Forty-four patients (mean age 66, SD 8 years) with either clinical evidence of a focal lacunar syndrome (n = 36) or with disorders of memory or gait (n = 8) in the presence of a lacunar infarct on CT were studied for cognitive functioning and for the presence of white matter lesions on MRI. MR images were assessed by a neurologist and a neuroradiologist blinded to the clinical data. Thirty-six patients had one or more lacunar infarcts on CT or MRI (in the thalamus in 5, in the caudate nucleus in 3 and in the internal capsule or corona radiata in the remaining patients). Twelve patients had multiple infarcts. Severe lesions of the white matted were found in 13 patients, mild to moderate lesions in 20 patients. Scores on Digit Span, Digit Symbol and delayed recall of the 15-Words test were significantly lower in the group with severe lesions, whilst there was a trend in the same direction for the Cognitive part of the Cambridge Examination of Mental Disorders in the Elderly, the Trailmaking B, Stroop colour interference test and the delayed visual reproduction of the Wechsler Memory Scale. These findings suggest that diffuse lesions of the white matter are an independent factor in the pathogenesis of intellectual dysfunction, also in patients with lacunar infarcts, but a truly independent analysis is difficult because the most severe involvement of the white matter tended to be associated with the largest number of lacunar infarcts

    Isometric Embedding of BPS Branes in Flat Spaces with Two Times

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    We show how non-near horizon p-brane theories can be obtained from two embedding constraints in a flat higher dimensional space with 2 time directions. In particular this includes the construction of D3 branes from a flat 12-dimensional action, and M2 and M5 branes from 13 dimensions. The worldvolume actions are determined by constant forms in the higher dimension, reduced to the usual expressions by Lagrange multipliers. The formulation affords insight in the global aspects of the spacetime geometries and makes contact with recent work on two-time physics.Comment: 29 pages, 10 figures, Latex using epsf.sty and here.sty; v2: reference added and some small correction

    Seeking creativity: A case study on information problem solving in professional music

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    This study explored the information seeking behavior of a professional jazz musician during creative work. It aimed at revealing information seeking activities necessary to execute present-day musical projects. A single case was studied in depth. First, a narrative interview was conducted to reveal project phases and corresponding information seeking behavior. Second, hereupon a semi-structured interview was taken to identify information seeking activities per phase. Results indicate that the musician deliberately searched for musical information especially in the first project phases. The internet was used as main source. Both data and goal driven strategies were applied, of which the latter were relatively scarce. This means that in this case the musician sporadically searched information based on a contemplated search plan. Future research should aim at generalizing findings of this case. It should further validate the underlying analytical framework that proved to be useful for describing and categorizing musical information seeking behavior

    Mapping migrant territories as topological deformations of space

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    Our research uses the concept of “territories” to describe the production of migrant space. The article describes a project based in London where the everyday practice of walking is used to map migrant territories, which are conceptualized as dispersed and overlapping, causing topological deformations to the actual lived space. We interrogate these deformations through focusing on the micro-scale and the everyday, mapping them as “scapes” and “spheres.” Using specific computational techniques, we transform the original walks into an architectural tool for investigating the fluctuations and flows of the contemporary city. In doing so, we approach territories from two distinct angles: from the geopolitical perspective of territories seen as the product of the interplay of politics, power, and space and from the biological perspective of territories seen as the primal need of all animals, including humans, for space and a certain distinction from their environment and from others

    CODE-EHR best practice framework for the use of structured electronic healthcare records in clinical research

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    Big data is central to new developments in global clinical science aiming to improve the lives of patients. Technological advances have led to the routine use of structured electronic healthcare records with the potential to address key gaps in clinical evidence. The covid-19 pandemic has demonstrated the potential of big data and related analytics, but also important pitfalls. Verification, validation, and data privacy, as well as the social mandate to undertake research are key challenges. The European Society of Cardiology and the BigData@Heart consortium have brought together a range of international stakeholders, including patient representatives, clinicians, scientists, regulators, journal editors and industry. We propose the CODE-EHR Minimum Standards Framework as a means to improve the design of studies, enhance transparency and develop a roadmap towards more robust and effective utilisation of healthcare data for research purposes

    Visualizing the Human Subcortex Using Ultra-high Field Magnetic Resonance Imaging

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