249 research outputs found

    Self-organized cortical map formation by guiding connections

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    We describe an algorithm for self-organizing connections from a source array to a target array of neurons that is inspired by neural growth cone guidance. Each source neuron projects a Gaussian pattern of connections to the target layer. Learning modifies the pattern center location. The small number of parameters required to specify connectivity has enabled this algorithm\u27s implementation in a neuromorphic silicon system. We demonstrate that this algorithm can lead to topographic feature maps similar to those observed in the visual cortex, and characterize its operation as function maximization, which connects this approach with other models of cortical map formation

    Effects of a Structured Exercise Programme on Functional Balance in Visually Impaired Elderly Living in a Residential Setting

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    AbstractOne major priority for health care professionals is to minimize the risk of fall in the elderly population. While the quality of life of an individual is affected by fall accidents, management of post-fall disability in the elderly could be a huge economic burden to the society. Visually impaired elderly are at a higher risk of fall, because “vision”, an important component contributing to balance, is disturbed. The aim of this study was to examine the effects of an exercise programme, which focused on improvement of the functional balance of visually impaired elderly. Visually impaired elderly residents were randomly assigned to either the exercise training or control group. A multidimensional, individually tailored exercise programme was introduced by physiotherapists to the exercise group for 12 weeks. Functional balance status reflected by the Berg Balance Scale, chair stand test, and timed up-and-go test assessed before and after the 12-week training programme was compared between the two groups. Results demonstrated a significant improvement in balance outcomes in the exercise group (p < 0.05) but not in the control group. The results of this study suggest that a physiotherapist-designed strengthening and balance-training programme can improve the functional balance status of visually impaired elderly

    A BGG-type resolution for tensor modules over general linear superalgebra

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    We construct a Bernstein-Gelfand-Gelfand type resolution in terms of direct sums of Kac modules for the finite-dimensional irreducible tensor representations of the general linear superalgebra. As a consequence it follows that the unique maximal submodule of a corresponding reducible Kac module is generated by its proper singular vector.Comment: 11pages, LaTeX forma

    Restoration of supersymmetric Slavnov-Taylor and Ward identities in presence of soft and spontaneous symmetry breaking

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    Supersymmetric Slavnov-Taylor and Ward identities are investigated in presence of soft and spontaneous symmetry breaking. We consider an abelian model where soft supersymmetry breaking yields a mass splitting between electron and selectron and triggers spontaneous symmetry breaking, and we derive corresponding identities that relate the electron and selectron masses with the Yukawa coupling. We demonstrate that the identities are valid in dimensional reduction and invalid in dimensional regularization and compute the necessary symmetry-restoring counterterms.Comment: 35 pages, LaTeX, 9 postscript figure

    Assessment of landuse/landcover dynamics of Kaduna watershed, using remote sensing data and GIS techniques

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    Watershed assessment and developmental strategy demands precise measurement of the past and present land use parameters. Failure of Shiroro dam in 1999 and 2004 was attributes to upstream soil erosion. Hence, the study of land use change within the corridors of the reservoir for proper understanding of the watershed dynamics becomes very crucial. These dynamics was studied for a period of 38 years (1975-2013) in the Kaduna watershed, north central Nigeria using Soil and Water Assessment Tool. The land-use land cover of the year 1975, 2000, and 2013 was reclassified into nine (9) classes in 1975 and eight (8) classes in 2000 and 2013, because of the extinction of Forest evergreen land use between 1975 and 2000. The classification shows the percentage land area of each of the land use type and the area in hectares. Findings revealed total extinction of the 0.03% of Forest evergreen land before 2000, in 2013 range grasses, forestmixed and wetlands-forested land-use have lost 23.92%, 2.06%, 3.77%, watershed land area respectively while, wetlands-mixed, agricultural land, water, barren and built-up land gained 0.18%, 27.81%, 0.53%, 0.02% and 1.25% respectively as at 2013. The lost in land-use area was attributed to human activities such as clearing and degradation of the natural landscape to another land-use type which posed a stern threat to the Shiroro dam downstream and the environment. If this persists it might contribute to global warming problems and land exposure to agents of erosion. Thus, appropriate best management practice of the watershed become essential

    Hyperbaric oxygen therapy improves colorectal anastomotic healing

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    Purpose: Hyperbaric oxygen treatment (HBOT) has been found to improve the healing of poorly oxygenated tissues. This study aimed to investigate the influence of HBOT on the healing in ischemic colorectal anastomosis. Methods: Forty Wistar rats were randomly divided into a treatment group that received HBOT for 10 consecutive days (7 days before and 3 days after surgery), or in a control group, which did not receive the therapy. Colectomy with an ischemic anastomosis was performed in all rats. In each group, the rats were followed for 3 or 7 days after surgery to determine the influence of HBOT on anastomotic healing. Results: Five rats from each group died during follow-up. No anastomotic dehiscence was seen in the HBOT group, compared to 37.5 % and 28.6 % dehiscence in the control group on postoperative day (POD) 3 and 7, respectively. The HBOT group had a significantly higher bursting pressure (130.9 ± 17.0 mmHg) than the control group (88.4 ± 46.7 mmHg; p = 0.03) on POD 3. On POD 3 and POD 7, the adhesion severity was significantly higher in the control groups than in the HBOT groups (p < 0.005). Kidney function (creatinine level) of the HBOT group was significantly better than of the control group on POD 7 (p = 0.001). Interestingly, a significantly higher number of CD206+ cells (marker for type 2 macrophages) was observed in the HBOT group at the anastomotic area on POD 3. Conclusion: Hyperbaric oxygen enhanced the healing of ischemic anastomoses in rats and improved the postoperative kidney function

    Mass measurements of neutron-deficient Y, Zr, and Nb isotopes and their impact on rp and Îœp nucleosynthesis processes

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    © 2018 The Authors. Published by Elsevier B.V. This manuscript is made available under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International licence (CC BY-NC-ND 4.0). For further details please see: https://creativecommons.org/licenses/by-nc-nd/4.0/Using isochronous mass spectrometry at the experimental storage ring CSRe in Lanzhou, the masses of 82Zr and 84Nb were measured for the first time with an uncertainty of ∌10 keV, and the masses of 79Y, 81Zr, and 83Nb were re-determined with a higher precision. The latter are significantly less bound than their literature values. Our new and accurate masses remove the irregularities of the mass surface in this region of the nuclear chart. Our results do not support the predicted island of pronounced low α separation energies for neutron-deficient Mo and Tc isotopes, making the formation of Zr–Nb cycle in the rp-process unlikely. The new proton separation energy of 83Nb was determined to be 490(400) keV smaller than that in the Atomic Mass Evaluation 2012. This partly removes the overproduction of the p-nucleus 84Sr relative to the neutron-deficient molybdenum isotopes in the previous Îœp-process simulations.Peer reviewe

    Use of plasma DNA to predict mortality and need for intensive care in patients with abdominal pain

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    Background We investigated the value of plasma deoxyribonucleic acid concentrations in patients presenting with acute abdominal pain to predict need for intensive care or mortality. Methods Plasma deoxyribonucleic acid taken from patients with acute abdominal pain was analyzed for the ÎČ-globin gene using the quantitative polymerase chain reaction. The primary outcome measure was the combined 28-day mortality or admission to the intensive care unit. Results Of 287 consecutive patients with acute abdominal pain recruited, 12 patients were admitted to the intensive care unit and/or died. Median plasma DNA concentrations were higher in patients with cancer and major organ inflammation. Mean plasma DNA concentrations were three-fold higher in patients with systemic inflammatory response syndrome, five-fold higher in patients who died within 28 days, and eight-fold higher in patients admitted to the intensive care unit. The area under the receiver operator curve for plasma DNA concentrations and intensive care unit admission/mortality was 0.804. At a cut-off of 1100 GE/ml, the sensitivity was 67% (95%CI 35–90) and specificity was 89% (95%CI 84–92). At a cut-off of 175 GE/ml, the sensitivity was 100% (95%CI 73–100) and specificity was 30% (95%CI 25–36). Plasma DNA concentration predicted need for intensive care unit admission or death (adjusted odds ratio 1.4; P < 0.0001). Conclusions Plasma DNA may have a role in patients with acute abdominal pain as a marker for inflammation and cancer, and a predictor of intensive care unit admission/mortality

    The hArtes Tool Chain

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    This chapter describes the different design steps needed to go from legacy code to a transformed application that can be efficiently mapped on the hArtes platform

    Search for W' bosons decaying to an electron and a neutrino with the D0 detector

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    This Letter describes the search for a new heavy charged gauge boson W' decaying into an electron and a neutrino. The data were collected with the D0 detector at the Fermilab Tevatron proton-antiproton Collider at a center-of-mass energy of 1.96 TeV, and correspond to an integrated luminosity of about 1 inverse femtobarn. Lacking any significant excess in the data in comparison with known processes, an upper limit is set on the production cross section times branching fraction, and a W' boson with mass below 1.00 TeV can be excluded at the 95% C.L., assuming standard-model-like couplings to fermions. This result significantly improves upon previous limits, and is the most stringent to date.Comment: submitted to Phys. Rev. Let
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