1,923 research outputs found

    Problems in the Surgical Management of Crohn's Disease of the Colon

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    Differences in the natural history of ulcerative colitis and colonic Crohn's disease which influence the choice and type of surgical treatment are discussed. The progressive nature of Crohn's disease is stressed. Drugs employed in the medical management of the disease are described with particular attention being drawn to their importance during surgical treatment. The indications for surgical treatment are outlined. Important complications of the disease, which we have encountered, are described. The types of surgical treatment employed in 35 patients with Crohn's disease of the colon treated during the last 2% years are presented with some details of the operative technique we have found to be important. No patient has died and the results have been good

    Quantized Skyrmion Fields in 2+1 Dimensions

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    A fully quantized field theory is developped for the skyrmion topological excitations of the O(3) symmetric CP1^1-Nonlinear Sigma Model in 2+1D. The method allows for the obtainment of arbitrary correlation functions of quantum skyrmion fields. The two-point function is evaluated in three different situations: a) the pure theory; b) the case when it is coupled to fermions which are otherwise non-interacting and c) the case when an electromagnetic interaction among the fermions is introduced. The quantum skyrmion mass is explicitly obtained in each case from the large distance behavior of the two-point function and the skyrmion statistics is inferred from an analysis of the phase of this function. The ratio between the quantum and classical skyrmion masses is obtained, confirming the tendency, observed in semiclassical calculations, that quantum effects will decrease the skyrmion mass. A brief discussion of asymptotic skyrmion states, based on the short distance behavior of the two-point function, is also presented.Comment: Accepted for Physical Review

    Bogoliubov Coefficients of 2D Charged Black Holes

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    We exactly calculate the thermal distribution and temperature of Hawking radiation for a two-dimensional charged dilatonic black hole after it has settled down to an "equilibrium" state. The calculation is carried out using the Bogoliubov coefficients. The background of the process is furnished by a preexisting black hole and not by collapsing matter as considered by Giddings and Nelson for the case of a Schwarzschild black hole. Furthermore, the vanishing of the temperature and/or the Hawking radiation in the extremal case is obtained as a regular limit of the general case.Comment: 9 pages, 1 eps figur

    De novo 2.3 Mb microdeletion of 1q32.2 involving the Van der Woude Syndrome locus

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    10.1186/1755-8166-6-31Molecular Cytogenetics61

    Feasibility, Compliance, and Efficacy of a Randomized Controlled Trial Using Vibration in Pre-pubertal Children

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    Objective: Interventions utilizing vibration may increase bone mass and size which may reduce forearm fractures in children. This randomized controlled pilot trial tested the feasibility, compliance and efficacy of forearm loading regimes in an after-school program in pre-pubertal children aged 6-10 years. Methods: A 12-week randomized controlled trial incorporated high (HMMS; N=10) and low (LMMS; N=10) magnitude mechanical stimulation vibration, floor exercises (N=9), and controls (N=10). Radial bone measures by DXA and pQCT were compared at the end of intervention (12-weeks) and 4-months post-intervention (4- months post). Results: Percent changes were significantly greater in floor vs. control for ultra-distal areal BMD by DXA at 12- weeks (1%[-2,5] vs.-5%[-8,-2] respectively, p=0.02) and 4-months post (5%[1,8] vs -2%[-5,2], p=0.03) and in HMMS vs. controls for trabecular vBMD by pQCT at 12-weeks (4%[0, 8], vs. -8% [-14, -2], p=0.02). Children exposed to HMMS showed positive changes in cortical BMC, area, and cortical vBMD after 12 weeks that remained 4 months post-intervention. Children exposed to floor exercise showed positive changes in cortical BMC, area, and periosteal circumference 4-months post-intervention. Controls had decreased trabecular BMD, but increased bone area and periosteal circumference. Conclusions: Exposure to floor exercise and HMMS increased trabecular aBMD and vBMD in the radius

    Semantic-based policy engineering for autonomic systems

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    This paper presents some important directions in the use of ontology-based semantics in achieving the vision of Autonomic Communications. We examine the requirements of Autonomic Communication with a focus on the demanding needs of ubiquitous computing environments, with an emphasis on the requirements shared with Autonomic Computing. We observe that ontologies provide a strong mechanism for addressing the heterogeneity in user task requirements, managed resources, services and context. We then present two complimentary approaches that exploit ontology-based knowledge in support of autonomic communications: service-oriented models for policy engineering and dynamic semantic queries using content-based networks. The paper concludes with a discussion of the major research challenges such approaches raise

    Energy-resolved spatial inhomogeneity of disordered Mott systems

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    We investigate the effects of weak to moderate disorder on the T=0 Mott metal-insulator transition in two dimensions. Our model calculations demonstrate that the electronic states close to the Fermi energy become more spatially homogeneous in the critical region. Remarkably, the higher energy states show the opposite behavior: they display enhanced spatial inhomogeneity precisely in the close vicinity to the Mott transition. We suggest that such energy-resolved disorder screening is a generic property of disordered Mott systems.Comment: 6 pages, 6 figures. Submitted to the Proceedings of the SCES 200

    Magnetic fluctuations in 2D metals close to the Stoner instability

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    We consider the effect of potential disorder on magnetic properties of a two-dimensional metallic system (with conductance g≫1g\gg 1) when interaction in the triplet channel is so strong that the system is close to the threshold of the Stoner instability. We show, that under these conditions there is an exponentially small probability for the system to form local spin droplets which are local regions with non zero spin density. Using a non-local version of the optimal fluctuation method we find analytically the probability distribution and the typical spin of a local spin droplet (LSD). In particular, we show that both the probability to form a LSD and its typical spin are independent of the size of the droplet (within the exponential accuracy). The LSDs manifest themselves in temperature dependence of observable quantities. We show, that below certain cross-over temperature the paramagnetic susceptibility acquires the Curie-like temperature dependence, while the dephasing time (extracted from magneto-resistance measurements) saturates.Comment: 15 pages, 4 figure

    Move blocking strategies in receding horizon control

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    Abstract — In order to deal with the computational burden of optimal control, it is common practice to reduce the degrees of freedom by fixing the input or its derivatives to be constant over several time-steps. This policy is referred to as “move blocking”. This paper will address two issues. First, a survey of various move blocking strategies is presented and the shortcomings of these blocking policies, such as the lack of stability and constraint satisfaction guarantees, will be illustrated. Second, a novel move blocking scheme, “Moving Window Blocking” (MWB), will be presented. In MWB, the blocking strategy is time-dependent such that the scheme yields stability and feasibility guarantees for the closed-loop system. Finally, the results of a large case-study are presented that illustrate the advantages and drawbacks of the various control strategies discussed in this paper

    Estimating the minimum important difference in the DEMQOL instrument in people with dementia

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    Purpose The Dementia-Related Quality of Life (DEMQOL) measure and the DEMQOL-Utility Score (DEMQOL-U) are validated tools for measuring quality of life (QOL) in people with dementia. What score changes translate to a clinically significant impact on patients’ lives was unknown. This study establishes the minimal important differences (MID) for these two instruments. Methods Anchor-based and distribution-based methods were used to estimate the MID scores from patients enrolled in a randomised controlled trial. For the anchor-based method, the global QOL (Q29) item from the DEMQOL was chosen as the anchor for DEMQOL and both Q29 and EQ-5D for DEMQOL-U. A one category difference in Q29, and a 0.07 point difference in EQ-5D score, were used to classify improvement and deterioration, and the MID scores were calculated for each category. These results were compared with scores obtained by the distribution-based methods. Results A total of 490 people with dementia had baseline DEMQOL data, of these 386 had 8-month data, and 344 had 12-month DEMQOL data. The absolute change in DEMQOL for a combined 1-point increase or decrease in the Q29 anchor was 5.2 at 8 months and 6.0 at 12 months. For the DEMQOL-U, the average absolute change at 8 and 12 months was 0.032 and 0.046 for the Q29 anchor and 0.020 and 0.024 for EQ-5D anchor. Conclusion We present MID scores for the DEMQOL and DEMQOL-U instruments obtained from a large cohort of patients with dementia. An anchored-based estimate of the MID for the DEMQOL is around 5 to 6 points; and 0.02 to 0.05 points for the DEMQOL-U. The results of this study can guide clinicians and researchers in the interpretation of these instruments comparisons between groups or within groups of people with dementia. Trial Registration Number and date of registration: ISRCTN17993825 on 11th October 2016
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