1,484 research outputs found

    Charged-Surface Instability Development in Liquid Helium; Exact Solutions

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    The nonlinear dynamics of charged-surface instability development was investigated for liquid helium far above the critical point. It is found that, if the surface charge completely screens the field above the surface, the equations of three-dimensional (3D) potential motion of a fluid are reduced to the well-known equations describing the 3D Laplacian growth process. The integrability of these equations in 2D geometry allows the analytic description of the free-surface evolution up to the formation of cuspidal singularities at the surface.Comment: latex, 5 pages, no figure

    Совершенствование автоматизированной системы управления блоком сепарации установки комплексной подготовки нефти

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    В настоящий момент имеется автоматизированная система контроля и управления блоком сепарации в установке комплексной подготовки нефти, но у данной системы есть ряд недостатков. Недостатками данной системы являются устаревающие средства управления и контроля, а так же отсутствие противоаварийной защиты. Все эти недостатки могут привести к серьезным проблемам. Актуальность работы состоит в совершенствовании технологий контроля и управления блоком сепарации путём внедрения противоаварийной защиты и замены устаревающих приборов контроля и управления блоком сепарации. Данные действия позволят повысить уровень безопасности на объекте, а так же усовершенствовать уровень контроля и управления.At the moment, there is an automated system for monitoring and controlling the separation unit in the complex oil treatment unit, but this system has a number of disadvantages. The disadvantages of this system are obsolete controls and controls, as well as the lack of emergency protection. All of these shortcomings can lead to serious problems. The relevance of the work consists in improving the technologies for monitoring and controlling the separation unit by introducing emergency protection and replacing the aging devices for monitoring and controlling the separation unit. These actions will increase the level of security at the facility, as well as improve the level of control and management

    An expert consensus on the recommendations for the use of biomarkers in Fabry disease

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    Fabry disease is an X-linked lysosomal storage disorder caused by the accumulation of glycosphingolipids in various tissues and body fluids, leading to progressive organ damage and life-threatening complications. Phenotypic classification is based on disease progression and severity and can be used to predict outcomes. Patients with a classic Fabry phenotype have little to no residual α-Gal A activity and have widespread organ involvement, whereas patients with a later-onset phenotype have residual α-Gal A activity and disease progression can be limited to a single organ, often the heart. Diagnosis and monitoring of patients with Fabry disease should therefore be individualized, and biomarkers are available to support with this. Disease-specific biomarkers are useful in the diagnosis of Fabry disease; non-disease-specific biomarkers may be useful to assess organ damage. For most biomarkers it can be challenging to prove they translate to differences in the risk of clinical events associated with Fabry disease. Therefore, careful monitoring of treatment outcomes and collection of prospective data in patients are needed. As we deepen our understanding of Fabry disease, it is important to regularly re-evaluate and appraise published evidence relating to biomarkers. In this article, we present the results of a literature review of evidence published between February 2017 and July 2020 on the impact of disease-specific treatment on biomarkers and provide an expert consensus on clinical recommendations for the use of those biomarkers

    3D Face Reconstruction from Light Field Images: A Model-free Approach

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    Reconstructing 3D facial geometry from a single RGB image has recently instigated wide research interest. However, it is still an ill-posed problem and most methods rely on prior models hence undermining the accuracy of the recovered 3D faces. In this paper, we exploit the Epipolar Plane Images (EPI) obtained from light field cameras and learn CNN models that recover horizontal and vertical 3D facial curves from the respective horizontal and vertical EPIs. Our 3D face reconstruction network (FaceLFnet) comprises a densely connected architecture to learn accurate 3D facial curves from low resolution EPIs. To train the proposed FaceLFnets from scratch, we synthesize photo-realistic light field images from 3D facial scans. The curve by curve 3D face estimation approach allows the networks to learn from only 14K images of 80 identities, which still comprises over 11 Million EPIs/curves. The estimated facial curves are merged into a single pointcloud to which a surface is fitted to get the final 3D face. Our method is model-free, requires only a few training samples to learn FaceLFnet and can reconstruct 3D faces with high accuracy from single light field images under varying poses, expressions and lighting conditions. Comparison on the BU-3DFE and BU-4DFE datasets show that our method reduces reconstruction errors by over 20% compared to recent state of the art

    The future of European Nephrology 'Guidelines' - a declaration of intent by European Renal Best Practice (ERBP)

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    The disparities of medical practice, together with a growing number of possible interventions, have increased the demand for well-conceived guidance for practitioners [1]. However, this development is hampered by the number and quality of scientific studies that test medical hypotheses, which are often unsatisfactory. This is especially true in nephrology, where well-conducted controlled trials are rare [2]. Because patients with renal failure are generally excluded from controlled studies in the general population [3], the development of sufficiently well-founded guidance in nephrology has always been difficult. With the development of European Best Practice Guidelines (EBPG), the European Renal Association–European Dialysis and Transplantation Association (ERA–EDTA) has created its own guidance-generating process. Similar initiatives have also arisen in the USA (Kidney Disease Outcome Initiative—K/DOQI), Australia (Caring for Australasians with Renal Impairment—CARI), Canada (Canadian Society of Nephrology—CSN), the UK (United Kingdom Renal Association—UKRA), as well as at several other locations around the world. These institutions have generated a plethora of often parallel recommendations on similar topics but sometimes with different messages [4]. The question can be asked: ‘Is there still a place for an institution generating European nephrology guidance?’ If there is, how should such an initiative be managed to conform with current demands? To answer these questions, the Council of ERA–EDTA set up a commission that convened three times in the course of 2008–09. The present text is a distillation of the discussions, reflections and final conclusions of this commission. It is an ad hoc document, reflecting the current status. In the future, concepts and attitudes might change, as medical thinking is influenced by changes in practice, needs, general philosophy, ethics and political/financial conditions

    Holocentric Chromosomes of Luzula elegans Are Characterized by a Longitudinal Centromere Groove, Chromosome Bending, and a Terminal Nucleolus Organizer Region

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    The structure of holocentric chromosomes was analyzed in mitotic cells of Luzula elegans. Light and scanning electron microscopy observations provided evidence for the existence of a longitudinal groove along each sister chromatid. The centromere-specific histone H3 variant, CENH3, colocalized with this groove and with microtubule attachment sites. The terminal chromosomal regions were CENH3-negative. During metaphase to anaphase transition, L. elegans chromosomes typically curved to a sickle-like shape, a process that is likely to be influenced by the pulling forces of microtubules along the holocentric axis towards the corresponding microtubule organizing regions. A single pair of 45S rDNA sites, situated distal to Arabidopsis-telomere repeats, was observed at the terminal region of one chromosome pair. We suggest that the 45S rDNA position in distal centromere-free regions could be required to ensure chromosome stability. Copyright (C) 2011 S. Karger AG, Base

    Microbial U isotope fractionation depends on U(VI) reduction rate

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    U isotope fractionation may serve as an accurate proxy for U(VI) reduction in both modern and ancient environments, if the systematic controls on the magnitude of fractionation (ε) are known. We model the effect of U(VI) reduction kinetics on U isotopic fractionation during U(VI) reduction by a novel Shewanella isolate, Shewanella sp. (NR), in batch incubations. The measured ε values range from 0.96 ± 0.16 to 0.36 ± 0.07‰ and are strongly dependent on the U(VI) reduction rate. The ε decreases with increasing reduction rate constants normalized by cell density and initial U(VI). Reactive transport simulations suggest that the rate dependence of ε is due to a two-step process, where diffusive transport of U(VI) from the bulk solution across a boundary layer is followed by enzymatic reduction. Our results imply that the spatial decoupling of bulk U(VI) solution and enzymatic reduction should be taken into account for interpreting U isotope data from the environment
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