71 research outputs found

    Early Indicators of Academic Difficulties in Children with Neurofibromatosis Type 1

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    Neurofibromatosis type 1 (NF1) is a genetic neurocutaneous disorder, with an estimated incidence of 1 in 3,000 persons. It is phenotypically variable disorder associated with elevated rates of intellectual disability and learning disabilities, attention problems, speech and language impairment, and executive functioning deficits. Research investigating the presentation of NF1 in preschool-age children is limited, but the data available indicate that cognitive difficulties are present and can be identified at an early age. There is also evidence from the general population that early neuropsychological deficits can be used to predict concurrent and later learning difficulties. The goal of the current study was to characterize the early learning profile of young children with NF1 and to determine which neuropsychological skills may contribute to academic difficulties. The results indicate that early learning difficulties are present and can be identified in young children with NF1. General intellectual functioning was strongly related to academic performance and accounted for many of the relations between neuropsychological and academic skills in the NF1 group. However, some specific neuropsychological skills continued to relate to foundational reading and math skills even when controlling for overall developmental level. These findings provide an indication of processing domains that may support academic skill development for future longitudinal work. Clinically, the findings suggest that cognitive screenings should be a routine part of care for young children with NF1. If appropriate interventions are implemented at an early age, academic skill development could be altered, preventing subtle learning difficulties from becoming more pronounced over time

    Excess free energy and Casimir forces in systems with long-range interactions of van-der-Waals type: General considerations and exact spherical-model results

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    We consider systems confined to a dd-dimensional slab of macroscopic lateral extension and finite thickness LL that undergo a continuous bulk phase transition in the limit Lā†’āˆžL\to\infty and are describable by an O(n) symmetrical Hamiltonian. Periodic boundary conditions are applied across the slab. We study the effects of long-range pair interactions whose potential decays as bxāˆ’(d+Ļƒ)b x^{-(d+\sigma)} as xā†’āˆžx\to\infty, with 2<Ļƒ<42<\sigma<4 and 2<d+Ļƒā‰¤62<d+\sigma\leq 6, on the Casimir effect at and near the bulk critical temperature Tc,āˆžT_{c,\infty}, for 2<d<42<d<4. For the scaled reduced Casimir force per unit cross-sectional area, we obtain the form L^{d} {\mathcal F}_C/k_BT \approx \Xi_0(L/\xi_\infty) + g_\omega L^{-\omega}\Xi\omega(L/\xi_\infty) + g_\sigma L^{-\omega_\sigm a} \Xi_\sigma(L \xi_\infty). The contribution āˆgĻƒ\propto g_\sigma decays for Tā‰ Tc,āˆžT\neq T_{c,\infty} algebraically in LL rather than exponentially, and hence becomes dominant in an appropriate regime of temperatures and LL. We derive exact results for spherical and Gaussian models which confirm these findings. In the case d+Ļƒ=6d+\sigma =6, which includes that of nonretarded van-der-Waals interactions in d=3d=3 dimensions, the power laws of the corrections to scaling āˆb\propto b of the spherical model are found to get modified by logarithms. Using general RG ideas, we show that these logarithmic singularities originate from the degeneracy Ļ‰=Ļ‰Ļƒ=4āˆ’d\omega=\omega_\sigma=4-d that occurs for the spherical model when d+Ļƒ=6d+\sigma=6, in conjunction with the bb dependence of gĻ‰g_\omega.Comment: 28 RevTeX pages, 12 eps figures, submitted to PR

    An introduction to phase transitions in stochastic dynamical systems

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    We give an introduction to phase transitions in the steady states of systems that evolve stochastically with equilibrium and nonequilibrium dynamics, the latter defined as those that do not possess a time-reversal symmetry. We try as much as possible to discuss both cases within the same conceptual framework, focussing on dynamically attractive `peaks' in state space. A quantitative characterisation of these peaks leads to expressions for the partition function and free energy that extend from equilibrium steady states to their nonequilibrium counterparts. We show that for certain classes of nonequilibrium systems that have been exactly solved, these expressions provide precise predictions of their macroscopic phase behaviour.Comment: Pedagogical talk contributed to the "Ageing and the Glass Transition" Summer School, Luxembourg, September 2005. 12 pages, 8 figures, uses the IOP 'jpconf' document clas

    Vaccine-Associated Enhanced Respiratory Disease Does Not Interfere with the Adaptive Immune Response Following Challenge with Pandemic A/H1N1 2009

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    The implications of sequential prime and challenge with mismatched influenza A viruses is a concern in mammals, including humans. We evaluated the ability of pigs affected with vaccine-associated enhanced respiratory disease (VAERD) to generate a humoral immune response against the heterologous challenge virus inciting the VAERD. Vaccinated and challenged (V/C) pigs were administered an inactivated swine Ī“-cluster H1N2 (MN08) vaccine with an HA similar to pre-2009 seasonal human viruses and challenged with heterologous A(H1N1) pandemic 2009 (H1N1pdm09). Vaccination induced MN08-specific hemagglutination inhibition (HI) antibody but not cross-reacting H1N1pdm09 HI antibody. However, vaccinated pigs demonstrated significantly higher post-challenge anti-H1N1pdm09 serum neutralizing (SN) antibodies at 14 and 21 days post inoculation (dpi) compared to nonvaccinated, challenged pigs (NV/C), indicating a priming effect of the vaccine. Serum and lung whole virus anti-H1N1pdm09ā€‰IgG ELISA antibodies in the vaccinated group were significantly higher than the challenge only pigs at all-time points evaluated. Lung IgA ELISA antibodies to both antigens were detected at 2, 5, and 21ā€‰dpi in vaccine-primed pigs, contrasted against mucosal ELISA antibody responses detected only at 21ā€‰dpi in the naĆÆve-challenged group. Collectively, vaccine-primed pigs demonstrated a robust humoral immune response and elevated local adaptive cytokine levels, indicating VAERD does not adversely affect the induction of an immune response to challenge with heterologous virus despite the severe clinical disease and underlying lung pathology. Thus, original antigenic sin does not appear to be a component of VAERD.This article is from Viral Immunology 26 (2013): 314, doi:10.1089/vim.2013.0018.</p

    "Best fit" framework synthesis: refining the method

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    Background Following publication of the first worked example of the ā€œbest fitā€ method of evidence synthesis for the systematic review of qualitative evidence in this journal, the originators of the method identified a need to specify more fully some aspects of this particular derivative of framework synthesis. Methods and Results We therefore present a second such worked example in which all techniques are defined and explained, and their appropriateness is assessed. Specified features of the method include the development of new techniques to identify theories in a systematic manner; the creation of an a priori framework for the synthesis; and the ā€œtestingā€ of the synthesis. An innovative combination of existing methods of quality assessment, analysis and synthesis is used to complete the process. This second worked example was a qualitative evidence synthesis of employeesā€™ views of workplace smoking cessation interventions, in which the ā€œbest fitā€ method was found to be practical and fit for purpose. Conclusions The method is suited to producing context-specific conceptual models for describing or explaining the decision-making and health behaviours of patients and other groups. It offers a pragmatic means of conducting rapid qualitative evidence synthesis and generating programme theories relating to intervention effectiveness, which might be of relevance both to researchers and policy-makers
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