1,187 research outputs found

    Stabilization of heterodimensional cycles

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    We consider diffeomorphisms ff with heteroclinic cycles associated to saddles PP and QQ of different indices. We say that a cycle of this type can be stabilized if there are diffeomorphisms close to ff with a robust cycle associated to hyperbolic sets containing the continuations of PP and QQ. We focus on the case where the indices of these two saddles differ by one. We prove that, excluding one particular case (so-called twisted cycles that additionally satisfy some geometrical restrictions), all such cycles can be stabilized.Comment: 31 pages, 9 figure

    Equilibration of High Molecular-Weight Polymer Melts: A Hierarchical Strategy

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    A strategy is developed for generating equilibrated high molecular-weight polymer melts described with microscopic detail by sequentially backmapping coarse-grained (CG) configurations. The microscopic test model is generic but retains features like hard excluded volume interactions and realistic melt densities. The microscopic representation is mapped onto a model of soft spheres with fluctuating size, where each sphere represents a microscopic subchain with NbN_{\rm b} monomers. By varying NbN_{\rm b} a hierarchy of CG representations at different resolutions is obtained. Within this hierarchy, CG configurations equilibrated with Monte Carlo at low resolution are sequentially fine-grained into CG melts described with higher resolution. A Molecular Dynamics scheme is employed to slowly introduce the microscopic details into the latter. All backmapping steps involve only local polymer relaxation thus the computational efficiency of the scheme is independent of molecular weight, being just proportional to system size. To demonstrate the robustness of the approach, microscopic configurations containing up to n=1000n=1000 chains with polymerization degrees N=2000N=2000 are generated and equilibration is confirmed by monitoring key structural and conformational properties. The extension to much longer chains or branched polymers is straightforward

    Applying Goldratt’s Framework to the Banking System

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    This paper describes the major elements of the Goldratt’s framework – the Theory of Constraints (TOC) – in the banking sector, and examines the factors involved in the decision to adopt the TOC by companies in this sector. Through a deep literature review, analyzing similar cases that apply the Goldratt’s framework in services and in manufacturing and the severalviews of its components, we aim at formulating a framework specifically for the banking system.The study uses a qualitative methodology supported by the information extracted from reality as it is framed in a multicase study model. As part of the quantitative approach, we test several research hypotheses raised from the review of existing studies in the area.The main factors that influence the decision to adopt the TOC are the nature and the characteristics of the banking service, the attitude towards change, the leadership and the commitment of the entire institution.By using the Goldratt’s approach outlined in this article, through the location of the constraints and develop practical measurement to facilitate the banking process improvements, banks can improve resource utilization, revenues and employee satisfaction

    Help-seeking behaviors for female sexual dysfunction: a cross sectional study from Iran

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    <p>Abstract</p> <p>Background</p> <p>Female sexual dysfunctions (FSD) are prevalent multifactor problems that in general remain misdiagnosed in primary health care. This population-based study investigated help-seeking behaviors among women with FSD in Iran.</p> <p>Methods</p> <p>This was a cross sectional study carried out in Kohgilouyeh-Boyer-Ahmad province in Iran. Using quota sampling all sexually active women aged 15 and over registered in primary health care delivery centers were studied. Experience of sexual problems was assessed using an ad-hoc questionnaire (Female sexual dysfunction: help-seeking behaviors survey) containing 14 items. Trained female nurses interviewed all participants after a verbal informed consent. Data were analyzed in a descriptive manner.</p> <p>Results</p> <p>In all 1540 women were studied. Of these, 786 (51%) cases had experienced at least one of the FSD problems. Results showed that 35.8% of women with FSD had sought no professional help and the most reasons for not seeking help were identified as: 'time constraints' and believing that it 'did not occur to me' (39.1 and 28.5% respectively). Sixty one percent of women who sought help for FSD reported that 'doctor gave me a definite diagnosis' and 'a definite treatment plan was given' in 57% of cases.</p> <p>Conclusion</p> <p>The study findings indicated that FSD problems were prevalent and many women did not seek help for their problem. Finding 'time constraints' and believing that the problem 'did not occur to me' as the most cited reasons for not seeking help might facilitate to understand potential barriers that exist in recognition and treatment of the female sexual dysfunctions. Since FSD might have a negative impact on interpersonal relationships and women's quality of life, it seems that there is need to address the problem both at local and national primary health care services.</p

    Levels of Angiopoietin 2 Are Predictive for Mortality in Patients Infected With Yellow Fever Virus

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    In 2018 there was a large yellow fever outbreak in São Paulo, Brazil, with a high fatality rate. Yellow fever virus can cause, among other symptoms, hemorrhage and disseminated intravascular coagulation, indicating a role for endothelial cells in disease pathogenesis. Here, we conducted a case-control study and measured markers related to endothelial damage in plasma and its association with mortality. We found that angiopoietin 2 is strongly associated with a fatal outcome and could serve as a predictive marker for mortality. This could be used to monitor severe cases and provide care to improve disease outcome

    Chaste: an open source C++ library for computational physiology and biology

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    Chaste - Cancer, Heart And Soft Tissue Environment - is an open source C++ library for the computational simulation of mathematical models developed for physiology and biology. Code development has been driven by two initial applications: cardiac electrophysiology and cancer development. A large number of cardiac electrophysiology studies have been enabled and performed, including high performance computational investigations of defibrillation on realistic human cardiac geometries. New models for the initiation and growth of tumours have been developed. In particular, cell-based simulations have provided novel insight into the role of stem cells in the colorectal crypt. Chaste is constantly evolving and is now being applied to a far wider range of problems. The code provides modules for handling common scientific computing components, such as meshes and solvers for ordinary and partial differential equations (ODEs/PDEs). Re-use of these components avoids the need for researchers to "re-invent the wheel" with each new project, accelerating the rate of progress in new applications. Chaste is developed using industrially-derived techniques, in particular test-driven development, to ensure code quality, re-use and reliability. In this article we provide examples that illustrate the types of problems Chaste can be used to solve, which can be run on a desktop computer. We highlight some scientific studies that have used or are using Chaste, and the insights they have provided. The source code, both for specific releases and the development version, is available to download under an open source Berkeley Software Distribution (BSD) licence at http://www.cs.ox.ac.uk/chaste, together with details of a mailing list and links to documentation and tutorials

    Comparative study of single and multislice computed tomography for assessment of the mandibular canal

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    OBJECTIVE: The purpose of this study was to evaluate the accuracy of relative measurements from the roof of the mandibular canal to the alveolar crest in multislice (multidetector) computed tomography (MDCT) and single-slice computed tomography (SSCT). MATERIAL AND METHODS: The sample consisted of 26 printed CT films (7 SSCT and 19 MDCT) from the files of the LABI-3D (3D Imaging Laboratory) of the School of Dentistry of the University of São Paulo (FOUSP), which had been acquired using different protocols. Two observers analyzed in a randomized and independent order a series of 22 oblique CT reconstructions of each patient. Each observer analyzed the CT scans twice. The length of the mandibular canal and the distance between the mandibular canal roof and the crest of the alveolar ridge were obtained. Dahlberg test was used for statistical analysis. RESULTS: The mean error found for the mandibular canal length measurements obtained from SSCT was 0.53 mm in the interobserver analysis, and 0.38 mm for both observers. On MDCT images, the mean error was 0.0 mm in the interobserver analysis, and 0.0 and 0.23 mm in the intraobserver analysis. Regarding the distance between the mandibular canal roof and the alveolar bone crest, the SSCT images showed a mean error of 1.16 mm in the interobserver analysis and 0.66 and 0.59 mm in the intraobserver analysis. In the MDCT images, the mean error was 0.72 mm in the interobserver analysis and 0.50 and 0.54 mm in the intraobserver analysis. CONCLUSION: Multislice CT was demonstrated a more accurate method and demonstrated high reproducibility in the analysis of important anatomical landmarks for planning of mandibular dental implants, namely the mandibular canal pathway and alveolar crest height
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