2,612 research outputs found

    Rhythmic inhibition allows neural networks to search for maximally consistent states

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    Gamma-band rhythmic inhibition is a ubiquitous phenomenon in neural circuits yet its computational role still remains elusive. We show that a model of Gamma-band rhythmic inhibition allows networks of coupled cortical circuit motifs to search for network configurations that best reconcile external inputs with an internal consistency model encoded in the network connectivity. We show that Hebbian plasticity allows the networks to learn the consistency model by example. The search dynamics driven by rhythmic inhibition enable the described networks to solve difficult constraint satisfaction problems without making assumptions about the form of stochastic fluctuations in the network. We show that the search dynamics are well approximated by a stochastic sampling process. We use the described networks to reproduce perceptual multi-stability phenomena with switching times that are a good match to experimental data and show that they provide a general neural framework which can be used to model other 'perceptual inference' phenomena

    The Environmental Imperative of Nuclear Disarmament

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    The world is threatened as never before by an insane buildup of nuclear weapons some five hundred times as strong in their explosive capacity as the latest estimate of all the chemical explosives that have ever been used throughout history. Leaders in major countries probably know the awful consequences of a nuclear war too well to start one, but the world has still to reckon with possible acts of aggression by other nations or flaring-up through technological failure, mechanical or other accident, malfunctioning or faulty feeding of computers, misinformation, neglect of machines or of constructional faults, terrorist or lunatic action, organized banditry, or the outcome of mere ‘acts of God'

    Knowledge, attitudes, and practices of community pharmacists toward the management of acne vulgaris in Palestine: a cross-sectional study

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    Background Acne vulgaris (AV) is a common dermatological disease affecting almost 85% of teenagers. Patients with AV usually present at community pharmacies during the early stages of their disease. Aim The aim of this study was to assess community pharmacists’ knowledge, attitudes, and practice toward AV management in West Bank in Palestine. Methods This study was a cross-sectional questionnaire-based study. The questionnaire included four sections: 1) demographic, 2) knowledge, 3) attitude and practice items related causes, and 4) treatment options and counseling during management of patients with AV. A convenience sampling method was implemented in this study. Parametric and non-parametric tests were used to compare different issues as appropriate. P < 0.05 were considered significant. Result A total of 270 community pharmacists were interviewed, and more than half (54.1%) were males. The study revealed that community pharmacists had an inadequate level of knowledge on management of AV; only 7.7% had high levels of knowledge. Pharmacists have positive attitude regarding AV management, but inadequate knowledge was reflected on their treatment practices; only 10% of participants independently dealt with AV without referral. Pharmacists with a low level of knowledge showed five times more referrals than those with a high level of knowledge (OR: 5.3; P < 0.001), and those with a bachelor degree showed three times more referrals than postgraduates (OR: 3.3; P < 0.001). Conclusion There is a demand to update dermatological knowledge of community pharmacists and encourage them to attend structured training programs about the management of AV.Funding source: None

    A Novel Approach in Pigment Printing Using Nano-keratin Based Binder

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    This study is devoted to preparation and characterization of nano-keratin based binder (NKBB) from cheap renewable natural resources, namely coarse Egyptian wool or feather. The prepared NKBB is utilized as a biodegradable, environment-friendly and relatively cheap binder in textile pigment printing of polyester, pure polyacrylic, viscose, polyester/viscose, and polyester/acrylic fabrics. Different concentrations of the prepared NKBB as well as its mixture with commercially produced one are used in the pigment printing paste. The colour strength of the printed fabrics as well as their fastness properties to light, washing, and perspiration are evaluated. The effect of the used binder on the bending stiffness of the printed fabrics is also assessed. Results show that the NKBB gives almost the same colour strength and fastness properties as the commercial binder with improved stiffness of the printed samples in relation to that printed with commercial one

    Diagnostic accuracy of physical examination findings for midfacial and mandibular fractures

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    Objectives: To assess the diagnostic accuracy of physical examination findings used to identify patients at risk for midfacial or mandibular fractures. Materials and Methods: A five-year retrospective cohort was constructed from all emergency department patients with a midfacial or mandibular trauma. The sensitivity, specificity, pre-test probability, positive predictive value, negative predictive value, positive likelihood ratio and negative likelihood ratio data was calculated for 19 and 14 physical examination findings for midfacial and mandibular fractures respectively. Computed Tomography and panoramic radiography were used as index tests. Results: A total of 1484 patients were identified among whom 40.4% midfacial and 33.4% mandibular fractures were diagnosed. Overall, specificity was found to be higher than sensitivity. Regarding midfacial fractures, high specificity was found for raccoon eyes, malar eminence flattening and all the findings that are related to palpation, the nasal, ocular and intra-oral assessment. Malar eminence flattening, external nasal deformity, nasal septum hematoma, change of globe position and palpable step-off had ad high positive predictive value and positive likelihood ratio. Regarding mandibular fractures high specificity was found for mouth opening restriction, auditory canal bleeding, intra-oral assessment related findings, palpable step-off, inferior alveolar nerve paresthesia, the angular compression test and chin axial pressure test. Conclusions: The diagnostic accuracy of relevant physical examination findings were identified for the prediction of midfacial and mandibular fractures. (C) 2021 The Author(s). Published by Elsevier Ltd

    Boundary and Coulomb Effects on Boson Systems in High-Energy Heavy-Ion Collisions

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    The boundary of a boson system plays an important role in determining the momentum distribution of the bosons. For a boson system with a cylindrical boundary, the momentum distribution is enhanced at high transverse momenta but suppressed at low transverse momenta, relative to a Bose-Einstein distribution. The boundary effects on systems of massless gluons and massive pions are studied. For gluons in a quark-gluon plasma, the presence of the boundary may modify the signals for the quark-gluon plasma. For pions in a pion system in heavy-ion collisions, Coulomb final-state interactions with the nuclear participants in the vicinity of the central rapidity region further modify the momentum distribution at low transverse momenta. By including both the boundary effect and the Coulomb final-state interactions we are able to account for the behavior of the π−\pi^{-} transverse momentum spectrum observed in many heavy-ion experiments, notably at low transverse momenta.Comment: 15 pages Postscript uuencoded tar-comprssed file, 9 Postscript figures uuencoded tar-compressed fil

    Cross-cultural adaptation of the Dutch Short Musculoskeletal Function Assessment questionnaire (SMFA-NL):Internal consistency, validity, repeatability and responsiveness

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    The purpose of this study was to translate and culturally adapt the Dutch version of the Short Musculoskeletal Function Assessment questionnaire (SMFA-NL) and to investigate the internal consistency, validity, repeatability and responsiveness of the translated version. The original SMFA was first translated and culturally adapted from English into Dutch according to a standardised procedure and subsequently tested for clinimetric quality. The study population consisted of 162 patients treated for various musculoskeletal injuries or disorders at the departments of Orthopedics and Traumatology. All respondents filled in the SMFA-NL and the SF-36 and a region-specific questionnaire. To determine repeatability, 87 respondents filled in the SMFA-NL for a second time after a time interval of three to four weeks. To determine responsiveness, 29 respondents who were treated for their injury within three months before the first assessment filled in the SMFA-NL for a second time after two to three months. The following analyses were performed to evaluate clinimetric quality of the SMFA-NL: factor analysis and Cronbach's alpha (internal consistency), floor and ceiling effects, Spearman's Rho (construct validity), intraclass correlation coefficients and the Bland & Altman method (repeatability), and standardised response means (SRM) (responsiveness). Factor analysis demonstrated four subscales of the SMFA-NL. Both the newly identified subscales of the SMFA-NL and the conventional subscales of the SMFA showed good internal consistency. No floor and some ceiling effects were found. Construct validity was good, as high correlations were found between the subscales of the SMFA-NL and the respective subscales of the SF-36 and the region-specific questionnaires. Repeatability of the SMFA-NL subscales was high, with no systematic bias between first and second assessment. Responsiveness of the SMFA-NL was moderate, as small to moderate SRMs were found. We successfully translated and culturally adapted a Dutch version of the Short Musculoskeletal Function Assessment questionnaire (SFMA-NL). This study shows that the SMFA-NL is a valid, reliable and moderately responsive method for the assessment of functional status of patients who have a broad range of musculoskeletal disorders. Furthermore, it will allow for comparison between different patient groups as well as for cross-cultural comparisons. (C) 2011 Elsevier Ltd. All rights reserved
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