1,236 research outputs found

    Renormalization of QCD_2

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    The low energy infrared scaling of the multi-color 2-dimensional quantum chromodynamics is determined in the framework of its bosonized model by using the functional renormalization group method with gliding sharp cut-off k in momentum space in the local potential approximation. The model exhibits a single phase with a superuniversal effective potential.Comment: 15 pages, 3 figures, final versio

    Patients, caregivers and health‐care professionals’ experience with an interdisciplinary intervention for people with multimorbidity in primary care: a qualitative study

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    Background : Multimorbidity challenges the health‐care system and requires innovative approaches. In 2015, a 4‐month patient‐centred interdisciplinary pragmatic intervention was implemented in primary care with the aim of supporting self‐management for patients with multimorbidity. Objective : To explore the perceptions and experiences of health‐care professionals, patients and their caregivers with a 4‐month patient‐centred interdisciplinary pragmatic intervention in primary care. Design : A descriptive, qualitative study using semi‐structured interviews was conducted. Setting and participants : A purposive sample of 30 participants was recruited from seven family medicine groups including patients, caregivers and health‐care professionals (HCPs). Interviews were analysed using Thorne's interpretive description approach. Results : Findings were grouped into the benefits and challenges of participating in the intervention. The programme allowed patients to adopt realistic and adapted objectives; to customize interventions to the patient's reality; and to help patients gain confidence, improve their knowledge, skills and motivation to manage their condition. Interprofessional collaboration eased the exchange of information via team meetings and electronic medical records. Challenges were related to collaboration, communication, coordination of work and integration of newly relocated HCPs mainly due to part‐time assignments and staff turnover. HCPs part‐time schedules limited their availability and hindered patients’ follow‐up. Discussion and conclusion : This intervention was useful and rewarding from the HCPs, patients and caregivers’ perspective. However, to ensure the success of this complex interdisciplinary intervention, implementers and managers should anticipate organizational barriers such as availability and time management of relocated HCPs

    Amyloid β 1-42 induces hypometabolism in human stem cell-derived neuron and astrocyte networks

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    Alzheimer's disease (AD) is the most common form of dementia, affecting more than 35 million people worldwide. Brain hypometabolism is a major feature of AD, appearing decades before cognitive decline and pathologic lesions. To date, the majority of studies on hypometabolism in AD have used transgenic animal models or imaging studies of the human brain. As it is almost impossible to validate these findings using human tissue, alternative models are required. In this study, we show that human stem cell-derived neuron and astrocyte cultures treated with oligomers of amyloid beta 1-42 (Aβ1-42) also display a clear hypometabolism, particularly with regard to utilization of substrates such as glucose, pyruvate, lactate, and glutamate. In addition, a significant increase in the glycogen content of cells was also observed. These changes were accompanied by changes in NAD+ /NADH, ATP, and glutathione levels, suggesting a disruption in the energy-redox axis within these cultures. The high energy demands associated with neuronal functions such as memory formation and protection from oxidative stress put these cells at particular risk from Aβ-induced hypometabolism. Further research using this model may elucidate the mechanisms associated with Aβ-induced hypometabolism

    ArteFill® Permanent Injectable for Soft Tissue Augmentation: I. Mechanism of Action and Injection Techniques

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    After more than 25 years of research and development, in October 2006 ArteFill® became the first and only permanent injectable wrinkle filler to receive FDA approval. ArteFill is a third-generation polymeric microsphere-based filler, following its predecessor Artecoll®, which was marketed outside the United States between 1994 and 2006. ArteFill is approved for the correction of nasolabial folds and has been used in over 15,000 patients since its U.S. market introduction in February 2007. No serious side effects have been reported to date according to the FDA’s MAUDE reporting database. ArteFill consists of polymethylmethacrylate (PMMA) microspheres (20% by volume), 30–50 μm in diameter, suspended in 3.5% bovine collagen solution (80% by volume) and 0.3% lidocaine. The collagen carrier is absorbed within 1 month after injection and completely replaced by the patient’s own connective tissue within 3 months. Each cc of ArteFill contains approximately six million microspheres and histological studies have shown that long-term wrinkle correction consists of 80% of the patient’s own connective tissue and 20% microspheres. The standard injection technique is subdermal tunneling that delivers a strand of ArteFill at the dermal–subdermal junction. This strand beneath a wrinkle or fold acts like a support structure that protects against further wrinkling and allows the diminished thickness of the dermis to recover to its original thickness

    Determining matrix elements and resonance widths from finite volume: the dangerous mu-terms

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    The standard numerical approach to determining matrix elements of local operators and width of resonances uses the finite volume dependence of energy levels and matrix elements. Finite size corrections that decay exponentially in the volume are usually neglected or taken into account using perturbation expansion in effective field theory. Using two-dimensional sine-Gordon field theory as "toy model" it is shown that some exponential finite size effects could be much larger than previously thought, potentially spoiling the determination of matrix elements in frameworks such as lattice QCD. The particular class of finite size corrections considered here are mu-terms arising from bound state poles in the scattering amplitudes. In sine-Gordon model, these can be explicitly evaluated and shown to explain the observed discrepancies to high precision. It is argued that the effects observed are not special to the two-dimensional setting, but rather depend on general field theoretic features that are common with models relevant for particle physics. It is important to understand these finite size corrections as they present a potentially dangerous source of systematic errors for the determination of matrix elements and resonance widths.Comment: 26 pages, 13 eps figures, LaTeX2e fil

    A Research of the Way of Pushing Forward the Development of Urban Community Service ---Taking Xiamen as an Example

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    城市社区是城市社会的基本单元。社区和谐则城市和谐。当前,随着我国社会结构发生深刻变化,城市化进程日益加速,加上家庭小型化、城市生活现代化,城市居民对城市社区服务的需求日益多样化和个性化。加强对我国城市社区服务发展推进路径的研究,促进城市社区服务的发展,提高城市社区服务水平,满足居民群众增长的服务需求,对于构建和谐社会、建设美丽中国,具有重大的现实意义。本文以厦门市为切入点,通过对城市社区服务工作的全面总结和深入分析,提出了推进城市社区服务发展的综合路径选择和具体对策措施。 首先,本文采用文献研究法、参与观察法和案例研究法,收集了厦门市城市社区服务工作的文献资料和数据,从社区服务硬件建设、机制...The urban community is a basic unit of urban society. When the community is harmonious, the city will be harmonious. Currently, with a profound change to China’s social structure and increasing acceleration of urbanization as well as miniaturization of families and modernization of urban life, urban residents’ demand of urban community service is increasingly diversified and individualized. It is ...学位:管理学硕士院系专业:公共事务学院_行政管理学号:1392010115049

    Large N and Bosonization in Three Dimensions

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    Bosonization is normally thought of as a purely two-dimensional phenomenon, and generic field theories with fermions in D>2 are not expected be describable by local bosonic actions, except in some special cases. We point out that 3D SU(N) gauge theories on R^{1,1} x S^{1}_{L} with adjoint fermions can be bosonized in the large N limit. The key feature of such theories is that they enjoy large N volume independence for arbitrary circle size L. A consequence of this is a large N equivalence between these 3D gauge theories and certain 2D gauge theories, which matches a set of correlation functions in the 3D theories to corresponding observables in the 2D theories. As an example, we focus on a 3D SU(N) gauge theory with one flavor of adjoint Majorana fermions and derive the large-N equivalent 2D gauge theory. The extra dimension is encoded in the color degrees of freedom of the 2D theory. We then apply the technique of non-Abelian bosonization to the 2D theory to obtain an equivalent local theory written purely in terms of bosonic variables. Hence the bosonized version of the large N three-dimensional theory turns out to live in two dimensions.Comment: 30 pages, 2 tables. v2 minor revisions, references adde

    Phase Structure and Compactness

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    In order to study the influence of compactness on low-energy properties, we compare the phase structures of the compact and non-compact two-dimensional multi-frequency sine-Gordon models. It is shown that the high-energy scaling of the compact and non-compact models coincides, but their low-energy behaviors differ. The critical frequency β2=8π\beta^2 = 8\pi at which the sine-Gordon model undergoes a topological phase transition is found to be unaffected by the compactness of the field since it is determined by high-energy scaling laws. However, the compact two-frequency sine-Gordon model has first and second order phase transitions determined by the low-energy scaling: we show that these are absent in the non-compact model.Comment: 21 pages, 5 figures, minor changes, final version, accepted for publication in JHE

    Low oxygen tension primes aortic endothelial cells to the reparative effect of tissue-protective cytokines

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    Erythropoietin (EPO) has both erythropoietic and tissue-protective properties. The EPO analogues carbamylated EPO (CEPO) and pyroglutamate helix B surface peptide (pHBSP) lack the erythropoietic activity of EPO but retain the tissue-protective properties that are mediated by a heterocomplex of EPO receptor (EPOR) and the β common receptor (βCR). We studied the action of EPO and its analogues in a model of wound healing where a bovine aortic endothelial cells (BAECs) monolayer was scratched and the scratch closure was assessed over 24 h under different oxygen concentrations. We related the effects of EPO and its analogues on repair to their effect on BAECs proliferation and migration (evaluated using a micro-Boyden chamber). EPO, CEPO and pHBSP enhanced scratch closure only at lower oxygen (5%), while their effect at atmospheric oxygen (21%) was not significant. The mRNA expression of EPOR was doubled in 5% compared to 21% oxygen, and this was associated with increased EPOR assessed by immunofluorescence and Western blot. By contrast βCR mRNA levels were similar in 5% and 21% oxygen. EPO and its analogues increased both BAECs proliferation and migration, suggesting that both may be involved in the reparative process. The priming effect of low oxygen tension on the action of tissue-protective cytokines may be of relevance to vascular disease, including atherogenesis and restenosis

    A multi-gene signature predicts outcome in patients with pancreatic ductal adenocarcinoma.

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    © 2014 Haider et al.; licensee BioMed Central. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.Improved usage of the repertoires of pancreatic ductal adenocarcinoma (PDAC) profiles is crucially needed to guide the development of predictive and prognostic tools that could inform the selection of treatment options
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