8 research outputs found

    Black holes, gravitational waves and fundamental physics: a roadmap

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    The grand challenges of contemporary fundamental physics—dark matter, dark energy, vacuum energy, inflation and early universe cosmology, singularities and the hierarchy problem—all involve gravity as a key component. And of all gravitational phenomena, black holes stand out in their elegant simplicity, while harbouring some of the most remarkable predictions of General Relativity: event horizons, singularities and ergoregions. The hitherto invisible landscape of the gravitational Universe is being unveiled before our eyes: the historical direct detection of gravitational waves by the LIGO-Virgo collaboration marks the dawn of a new era of scientific exploration. Gravitational-wave astronomy will allow us to test models of black hole formation, growth and evolution, as well as models of gravitational-wave generation and propagation. It will provide evidence for event horizons and ergoregions, test the theory of General Relativity itself, and may reveal the existence of new fundamental fields. The synthesis of these results has the potential to radically reshape our understanding of the cosmos and of the laws of Nature. The purpose of this work is to present a concise, yet comprehensive overview of the state of the art in the relevant fields of research, summarize important open problems, and lay out a roadmap for future progress. This write-up is an initiative taken within the framework of the European Action on 'Black holes, Gravitational waves and Fundamental Physics'

    Properties of the extreme charged black hole near horizon

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    It is known, that there exists a limiting correspondence between certain part (including the horizon) of extremal case of Reissner-Nordström space-time and Robinson-Bertotti space-time and that different generalisations of this near-horizon limit are possible. The aim of the presented work is to examine some of the properties of such limiting transitions. Firstly it is stressed how the global structure is reflected in the limit and secondly which properties of the space-time do provide that physical distances are preserved in the limit. Besides the extremal case the subextremal and hyperextremal generalisations are studied. As a complementary topic, the global extremal limit is stated. That means a transition from a generalised (non-symmetrical) conformal diagram of the subextremal case to the conformal diagram of the extremal case of Reissner-Nordström solution

    Částice a pole v křivých prostoročasech (vybrané problémy)

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    In 2009 Bañados, Silk and West described the possibility of principally unbounded collision energies in the centre-of-mass frame for the particle collisions in the vicinity of black holes. Their work attracted a big response. This thesis aims to summarise the results of a number of the articles about the topic and puts these results into a new, broader context. It also presents some generalisations of the existing results, especially for models of magnetised black holes. The main subject of interest is the question, whether the unbounded collision energies can be achieved in a single-scattering or multiple-scattering process which was first formulated by Grib, Pavlov and Zaslavskii. Variety of methods is summarised. A considerable attention is paid to the limiting near-horizon description, which is further developed in order to derive new links and relations among known results, particularly between the purely theoretical work dealing with the geometry of degenerate horizons and their vicinity and more astrophysical articles about magnetic fluxes. Powered by TCPDF (www.tcpdf.org

    Czech restaurant information dataset for NLG

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    This is a dataset for natural language generation (NLG) in task-oriented spoken dialogue systems with Czech as the target language. It originated as a translation of the English San Francisco Restaurants dataset by Wen et al. (2015). It includes input dialogue acts and the corresponding output natural language paraphrases in Czech. Since the dataset is intended for recurrent neural network based NLG systems using delexicalization, inflection tables for all slot values appearing verbatim in the text are provided

    Clinical and Ultrasound Characteristics of the Microcystic Elongated and Fragmented (MELF) Pattern in Endometrial Cancer According to the International Endometrial Tumor Analysis (IETA) criteria

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    OBJECTIVES: To describe sonographic features of the microcystic elongated and fragmented (MELF) pattern of myometrial invasion (MI) using the International Endometrial Tumor Analysis (IETA) criteria; to assess the effect of the MELF pattern on preoperative ultrasound evaluation of MI; and to determine the relationship of the MELF pattern to more advanced stage ( 65 IB) and lymph node metastases (LNM) in women with endometrioid endometrial cancer (EEC). METHODS/MATERIALS: We included 850 women with EEC from the prospective IETA 4 study. Ultrasound experts performed all ultrasound examinations, accordingto the IETA protocol. Reference pathologists assessed the presence orabsence of the MELF pattern. Sonographic features and accuracy of ultrasound assessment of MI were compared in cases with the presence and the absence of the MELF pattern. The MELF pattern was correlated to more advanced stage ( 65IB) and LNM. RESULTS: The MELF pattern was present in 197 (23.2%) women. On preoperative ultrasound imaging the endometrium was thicker (p = 0.031), more richly vascularized (p = 0.003) with the multiple multifocal vessel pattern (p < 0.001) and the assessment of adenomyosis was more often uncertain (p < 0.001). The presence or the absence of the MELF pattern did not affect the accuracy of the assessment of MI. The MELF pattern was associated with MI 65 50% (p < 0.001), cervical stromal invasion (CSI) (p = 0.037), more advanced stage ( 65 IB) (p < 0.001) and LNM (p = 0.011). CONCLUSIONS: Tumors with the MELF pattern were slightly larger, more richly vascularized with multiple multifocal vessels and assessment of adenomyosis was more uncertain on ultrasound imaging. The MELF pattern did not increase the risk of underestimating MI in preoperative ultrasound staging. Tumors with the MELF pattern were more than twice as likely to have more advanced stage ( 65 IB) and LNM
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