64 research outputs found

    Functorial prolongations of some functional bundles

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    We discuss two kinds of functorial prolongations of the functional bundle of all smooth maps between the fibers over the same base point of two fibered manifolds over the same base. We study the prolongation of vector fields in both cases and we prove that the bracket is preserved. Our proof is based on several new results concerning the finite dimensional Weil bundles

    Modern vehicles for regional railways

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    The paper analyses the history of two-axle rail vehicles (rail buses) used for operation on regional lines in Czechoslovakia. It also shows trends in the development of modern light autonomous rolling stocks usable for passenger transport on unprofitable regional lines in Western Europe. The measures adopted in the transport policy of the Czech Republic for the period 2021–2027 for regional railway vehicles in the Czech Republic are presented. The final part of the paper presents the results of study of the concepts of a two-axle hybrid and electric rail buses and a conceptual design of a modular solution of a partially low-floor vehicle BEMU and HEMU for passenger regional rail transport. This paper shows that it is very problematic to create a light rail vehicle (LVR) that will be economical and environmentally friendly for regional transport and at the same time will meet the requirements of standards ČSN EN 12 663, category P2 and ČSN EN 15 227, category C I and will be friendly to road users

    Design of a Wheelset Drive

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    The paper describes trends in individualwheelset drive and drives of the independently rotatingwheels of modern low-floor trams and railway vehicles. Itdocuments the way of a constructive design of the individualwheelset drive (without gearbox) and wheelset drive withgearboxes

    Modern railways for the 21st century – a challenge not only for designers

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    The paper outlines the basic goals for modern rail transport in the Czech Republic. This contribution points out some challenges and technical tasks that project engineers and operators of the rail transport in the Czech Republic will have to deal with if they want to succeed in the conditions of the liberalized European railway market after the year 2035. Moreover, the article assesses the demands placed on safety of the railway transport and presents suggestions for reduction of the consequences of a rolling stock-car collisions in the regional transport

    Analysis of a Partly Sprung Drive

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    During the operation of trams in citiesthe bogies and drives are dynamically loaded throughacceleration, deceleration, passaging curves andevidently by the roughness of the tram track. Theseadded dynamic loads can significantly increase thewearing of tram drive components. The aim of thisanalysis is the investigation of stress state and motionsof the gearbox hinge (support). For this purpose,strain gauges and optical system Qualisys are used.Special type of the strain gauges arrangement formeasuring tension and bend together is designed.Acquired data are processed in the software Matlaband in the user interface of the Qualisys software

    Primitive neuroectodermal tumor (PNET) of the lung in an adult woman

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    Primary primitive neuroectodermal tumors (PNETs) are extremely rare in the lung and especially in adult women. We describe a case of PNET of the lung with aggressive behavior in 31-year-old woman. Diagnosis was based on histopathological and immunohistochemical studies, and confirmed by molecular genetic analysis of chromosome rearrangements in the EWSR1 gene region. Clinical follow-up, post-mortem findings, and differential diagnosis are also discussed. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/1477-7819-12-374) contains supplementary material, which is available to authorized users

    Cell segmentation methods for label-free contrast microscopy: review and comprehensive comparison

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    Because of its non-destructive nature, label-free imaging is an important strategy for studying biological processes. However, routine microscopic techniques like phase contrast or DIC suffer from shadow-cast artifacts making automatic segmentation challenging. The aim of this study was to compare the segmentation efficacy of published steps of segmentation work-flow (image reconstruction, foreground segmentation, cell detection (seed-point extraction) and cell (instance) segmentation) on a dataset of the same cells from multiple contrast microscopic modalities

    Dynamic changes in genomic and social structures in third millennium BCE central Europe

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    Europe’s prehistory oversaw dynamic and complex interactions of diverse societies, hitherto unexplored at detailed regional scales. Studying 271 human genomes dated ~4900 to 1600 BCE from the European heartland, Bohemia, we reveal unprecedented genetic changes and social processes. Major migrations preceded the arrival of “steppe” ancestry, and at ~2800 BCE, three genetically and culturally differentiated groups coexisted. Corded Ware appeared by 2900 BCE, were initially genetically diverse, did not derive all steppe ancestry from known Yamnaya, and assimilated females of diverse backgrounds. Both Corded Ware and Bell Beaker groups underwent dynamic changes, involving sharp reductions and complete replacements of Y-chromosomal diversity at ~2600 and ~2400 BCE, respectively, the latter accompanied by increased Neolithic-like ancestry. The Bronze Age saw new social organization emerge amid a ≥40% population turnover.Peer reviewe
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