1,512 research outputs found

    Event-related potentials and monoamines in autistic children on a clinical trial of fenfluramine

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    Introduction: As autistic persons have problems with selecting and encoding meaningful stimuli and multi-centre studies (Ritvo et al., 1983, 1986) had reported mild behavioural improvements following treatment with fenfluramine, event-related potential (ERP) stages of information processing were studied in childhood autism as part of a double blind crossover study of the efficacy of dl fenfluramine. . Methods: Acceptable recordings were derived from midline and 4 lateral sites on the scalp of 7 from 14 young persons with autism who understood the task (6 male, 1 female 5.8-17.7 years-of-age). A three-tone oddball paradigm was presented in a passive and active-task form (72% at 1 kHz, 14% at 0.5 kHz and 14% at 2.0 kHz) under placebo and drug conditions (where each condition lasted 5 months). Eleven patients provided blood and urine samples for monoamine analyses in both conditions. Results: a) With fenfluramine treatment blood serotonin decreased and urinary catecholamine levels fell (25-45%, but dopamine utilization (HVA/DA) increased 2-4-fold. b) Under fenfluramine autistic subjects responded non-significantly faster, with fewer errors of omission and improved /decreased beta criterion (signal detection). [IQ measures increased 7.5 points.] c) N1 amplitudes (Fz) decreased and latencies increased in the fenfluramine condition. Early negativity (especially on the right) correlated inversely with HVA/DA actvivity. Subtraction of the ERPs in nontarget from target conditions showed that the Negative difference (Nd) increased during fenfluramine treatment. d) P3 amplitudes (especially after the deviants) increased with fenfluramine treatment. But in the difference waveform (active-minus-passive condition) the P3 amplitude was halved. The distribution of the P3 component moved rostrally with treatment. Conclusions: N1 and P3 components of the ERP were responsive to fenfluramine treament. Treatment appears to have mildly improved early stimulus processing at stages represented by the early negative components, but to have mildly impaired processing at the P3-stage. The N1 / Nd - related improvement seems to be related to increased dopamine activity (cf. neuroleptic-like properties of racemate fenfluramine)

    Broadening the Scope of Nanopublications

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    In this paper, we present an approach for extending the existing concept of nanopublications --- tiny entities of scientific results in RDF representation --- to broaden their application range. The proposed extension uses English sentences to represent informal and underspecified scientific claims. These sentences follow a syntactic and semantic scheme that we call AIDA (Atomic, Independent, Declarative, Absolute), which provides a uniform and succinct representation of scientific assertions. Such AIDA nanopublications are compatible with the existing nanopublication concept and enjoy most of its advantages such as information sharing, interlinking of scientific findings, and detailed attribution, while being more flexible and applicable to a much wider range of scientific results. We show that users are able to create AIDA sentences for given scientific results quickly and at high quality, and that it is feasible to automatically extract and interlink AIDA nanopublications from existing unstructured data sources. To demonstrate our approach, a web-based interface is introduced, which also exemplifies the use of nanopublications for non-scientific content, including meta-nanopublications that describe other nanopublications.Comment: To appear in the Proceedings of the 10th Extended Semantic Web Conference (ESWC 2013

    Vapour-liquid coexistence in many-body dissipative particle dynamics

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    Many-body dissipative particle dynamics is constructed to exhibit vapour-liquid coexistence, with a sharp interface, and a vapour phase of vanishingly small density. In this form, the model is an unusual example of a soft-sphere liquid with a potential energy built out of local-density dependent one-particle self energies. The application to fluid mechanics problems involving free surfaces is illustrated by simulation of a pendant drop.Comment: 8 pages, 6 figures, revtex

    Blood Pressure Control for African American Parents and Children: Feasibility and Initial Outcomes of a Faith-based Intervention Pilot Study

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    The overall purpose was to determine the feasibility and initial outcomes of a faith-based intervention to improve blood pressure (BP) control in African American (AA) parents/guardians and their children, using a pre/post without control group design. Sample included AA parents and children (n=17) from three churches in North Florida. Health behaviors (daily servings of fruits/vegetables [F/V], minutes of physical activity [PA]) and physical health (BMI, systolic BP and diastolic SB) were examined. Data were analyzed using descriptive statistics, paired t-tests, and correlations. Feasibility outcomes showed high attendance (91% children, 88% parents) and completion (100%) rates. F/V significantly increased at post-test in adults (p=.02) and approached significance in children (p=.07). Positive trends at post-test were noted in PA, BMI, SBP and DBP in both groups. There were significant correlations at post-test for F/V (p=.01) and SBP (p=.006) for the parent/child dyads. Findings suggest that the intervention was feasible and has promise to improve health outcomes

    A new dawn? The Roman Catholic Church and environmental issues

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    This is a PDF version of an article published in New Blackfriars© 1997. The definitive version is available at www.blackwell-synergy.com.This article discusses the stance of the Roman Catholic Church on environmental issues and argues that the Church tends to stay on the fringe rather than get involved. Some of the ways in which Roman Catholic theologians have incorporated environmental issues into theological reflection is discussed, as are environmental challenges facing the Church in Britain (conservation, resources, biodiversity, animal welfare, biotechnology, cooperate/individual ethics, environmental justice, economics/policy development, and global issues)

    Hardware and software status of QCDOC

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    QCDOC is a massively parallel supercomputer whose processing nodes are based on an application-specific integrated circuit (ASIC). This ASIC was custom-designed so that crucial lattice QCD kernels achieve an overall sustained performance of 50% on machines with several 10,000 nodes. This strong scalability, together with low power consumption and a price/performance ratio of $1 per sustained MFlops, enable QCDOC to attack the most demanding lattice QCD problems. The first ASICs became available in June of 2003, and the testing performed so far has shown all systems functioning according to specification. We review the hardware and software status of QCDOC and present performance figures obtained in real hardware as well as in simulation.Comment: Lattice2003(machine), 6 pages, 5 figure

    When Does Eddy Viscosity Damp Subfilter Scales Sufficiently?

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    Large eddy simulation (LES) seeks to predict the dynamics of spatially filtered turbulent flows. The very essence is that the LES-solution contains only scales of size ≥Δ, where Δ denotes some user-chosen length scale. This property enables us to perform a LES when it is not feasible to compute the full, turbulent solution of the Navier-Stokes equations. Therefore, in case the large eddy simulation is based on an eddy viscosity model we determine the eddy viscosity such that any scales of size <Δ are dynamically insignificant. In this paper, we address the following two questions: how much eddy diffusion is needed to (a) balance the production of scales of size smaller than Δ; and (b) damp any disturbances having a scale of size smaller than Δ initially. From this we deduce that the eddy viscosity νe has to depend on the invariants q = ½tr(S^2) and r =−⅓tr(S^3) of the (filtered) strain rate tensor S. The simplest model is then given by νe = 3/2(Δ/π)^2|r|/q. This model is successfully tested for a turbulent channel flow (Reτ = 590).

    High tibial osteotomy: a review of the readability and quality of patient information on the internet

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    Background: High tibial osteotomy (HTO) is a common procedure performed for unicompartmental knee osteoarthritis (OA). Patients are increasingly using the internet to research surgical procedures to help aid decision making. Our aim was to assess the readability and quality of information available to patients online relating to HTO. Methods: A systematic review of three search engines Google, Bing, and Yahoo using the search terms “high tibial osteotomy” and “tibial osteotomy” separately was performed. The first three pages of results for each search engine were analyzed. Readability was assessed using the Flesch Reading Ease Scale (FRES), Flesch-Kincaid Grade level (FKGL) and the Simple Measure of Gobbledygook formula (SMOG). Quality was assessed with the DISCERN questionnaire, JAMAbenchmarks and the presence of Health on the Net Foundation Code of Conduct (HONCode). Results: Twenty-four webpages were included after duplicates (n=42) and exclusions (n=24).The overall readability was low, with a mean FRES of 53.2 (SD: 9.1), FKGL 10.7 (SD: 1.8),SMOG 10.4 (SD: 1.5). Quality was also low with a mean DISCERN score of 42 (SD: 12.3).None of the webpages fulfilled all of the JAMA benchmarking criteria and only 2/24 (8.3%)webpages possessed HONCode certification. Conclusion: The overall online information available to patient’s considering HTO is of lowreadability and quality. Improving the quality and readability of patient information online willbenefit informed patient decision making before HTO surgery

    Tick size and price diffusion

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    A tick size is the smallest increment of a security price. It is clear that at the shortest time scale on which individual orders are placed the tick size has a major role which affects where limit orders can be placed, the bid-ask spread, etc. This is the realm of market microstructure and there is a vast literature on the role of tick size on market microstructure. However, tick size can also affect price properties at longer time scales, and relatively less is known about the effect of tick size on the statistical properties of prices. The present paper is divided in two parts. In the first we review the effect of tick size change on the market microstructure and the diffusion properties of prices. The second part presents original results obtained by investigating the tick size changes occurring at the New York Stock Exchange (NYSE). We show that tick size change has three effects on price diffusion. First, as already shown in the literature, tick size affects price return distribution at an aggregate time scale. Second, reducing the tick size typically leads to an increase of volatility clustering. We give a possible mechanistic explanation for this effect, but clearly more investigation is needed to understand the origin of this relation. Third, we explicitly show that the ability of the subordination hypothesis in explaining fat tails of returns and volatility clustering is strongly dependent on tick size. While for large tick sizes the subordination hypothesis has significant explanatory power, for small tick sizes we show that subordination is not the main driver of these two important stylized facts of financial market.Comment: To be published in the "Proceedings of Econophys-Kolkata V International Workshop on "Econophysics of Order-driven Markets" March 9-13, 2010, The New Economic Windows series of Springer-Verlag Italia

    An integral method for solving nonlinear eigenvalue problems

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    We propose a numerical method for computing all eigenvalues (and the corresponding eigenvectors) of a nonlinear holomorphic eigenvalue problem that lie within a given contour in the complex plane. The method uses complex integrals of the resolvent operator, applied to at least kk column vectors, where kk is the number of eigenvalues inside the contour. The theorem of Keldysh is employed to show that the original nonlinear eigenvalue problem reduces to a linear eigenvalue problem of dimension kk. No initial approximations of eigenvalues and eigenvectors are needed. The method is particularly suitable for moderately large eigenvalue problems where kk is much smaller than the matrix dimension. We also give an extension of the method to the case where kk is larger than the matrix dimension. The quadrature errors caused by the trapezoid sum are discussed for the case of analytic closed contours. Using well known techniques it is shown that the error decays exponentially with an exponent given by the product of the number of quadrature points and the minimal distance of the eigenvalues to the contour
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