1,996 research outputs found

    Introdução à biomecânica do esporte considerações sobre métodos de investigação

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    Através de análise da literatura específica, discute-se o domínio da área de atuação da Biomecânica do Esporte, a interdisciplinaridade de Ciências Esportivas para a investigação do movimento e padronização conceituai, quanto à composição, classificação e metas na investigação. Quanto aos métodos de medidas, discutem-se os principais processos e suas características, visando a complexa investigação para a análise do movimento esportiv

    A STUDY OF THE MECHANICAL ENERGY DIFFERENCES BETWEEN TREADMILL AND OVERGROUND WALKING

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    The aim of this paper was to analyze the components of the mechanical energy of the body considering the differences between treadmill and overground walking. One subject was filmed while walking at 1.5 m/s on treadmill and overground. The results show that the patterns of the curves are very similar, but the change in the total energy, both in the upper as in the lower extremity were greater on overground (23.20J and 17.47J respectively for overground and treadmill and for the upper extremity 4.91J and 2.56J). The potential energy change of the trunk was also greater on overground (overground 45.97J; treadmill 24.88J). These findings, showing a lower measured mechanical cost on treadmill address the problem whether the treadmill can be used as a valid simulator for overground walking

    Precursor-Dependent Photocatalytic Activity of Carbon Dots

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    This work systematically compares both structural features and photocatalytic performance of a series of graphitic and amorphous carbon dots (CDs) prepared in a bottom-up manner from fructose, glucose, and citric acid. We demonstrate that the carbon source and synthetic procedures diversely affect the structural and optical properties of the CDs, which in turn unpredictably influence their photo electron transfer ability. The latter was evaluated by studying the photo-reduction of methyl viologen. Overall, citric acid-CDs were found to provide the best photocatalytic performance followed by fructose- and glucose-CDs. However, while the graphitization of glucose- and citric acid-CDs favored the photo-reaction, a reverse structure-activity dependence was observed for fructose-CDs due to the formation of a large graphitic-like supramolecular assembly. This study highlights the complexity to design in advance photo-active bio-based carbon nanomaterials

    Safer_RAIN: A DEM-based hierarchical filling-&-spilling algorithm for pluvial flood hazard assessment and mapping across large urban areas

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    The increase in frequency and intensity of extreme precipitation events caused by the changing climate (e.g., cloudbursts, rainstorms, heavy rainfall, hail, heavy snow), combined with the high population density and concentration of assets, makes urban areas particularly vulnerable to pluvial flooding. Hence, assessing their vulnerability under current and future climate scenarios is of paramount importance. Detailed hydrologic-hydraulic numerical modeling is resource intensive and therefore scarcely suitable for performing consistent hazard assessments across large urban settlements. Given the steadily increasing availability of LiDAR (Light Detection And Ranging) high-resolution DEMs (Digital Elevation Models), several studies highlighted the potential of fast-processing DEM-based methods, such as the Hierarchical Filling-&-Spilling or Puddle-to-Puddle Dynamic Filling-&-Spilling Algorithms (abbreviated herein as HFSAs). We develop a fast-processing HFSA, named Safer_RAIN, that enables mapping of pluvial flooding in large urban areas by accounting for spatially distributed rainfall input and infiltration processes through a pixel-based Green-Ampt model. We present the first applications of the algorithm to two case studies in Northern Italy. Safer_RAIN output is compared against ground evidence and detailed output from a two-dimensional (2D) hydrologic and hydraulic numerical model (overall index of agreement between Safer_RAIN and 2D benchmark model: sensitivity and specificity up to 71% and 99%, respectively), highlighting potential and limitations of the proposed algorithm for identifying pluvial flood-hazard hotspots across large urban environments

    Curricular orientations to real-world contexts in mathematics

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    A common claim about mathematics education is that it should equip students to use mathematics in the ‘real world’. In this paper, we examine how relationships between mathematics education and the real world are materialised in the curriculum across a sample of eleven jurisdictions. In particular, we address the orientation of the curriculum towards application of mathematics, the ways that real-world contexts are positioned within the curriculum content, the ways in which different groups of students are expected to engage with real-world contexts, and the extent to which high-stakes assessments include real-world problem solving. The analysis reveals variation across jurisdictions and some lack of coherence between official orientations towards use of mathematics in the real world and the ways that this is materialised in the organisation of the content for students

    A criterion for separating process calculi

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    We introduce a new criterion, replacement freeness, to discern the relative expressiveness of process calculi. Intuitively, a calculus is strongly replacement free if replacing, within an enclosing context, a process that cannot perform any visible action by an arbitrary process never inhibits the capability of the resulting process to perform a visible action. We prove that there exists no compositional and interaction sensitive encoding of a not strongly replacement free calculus into any strongly replacement free one. We then define a weaker version of replacement freeness, by only considering replacement of closed processes, and prove that, if we additionally require the encoding to preserve name independence, it is not even possible to encode a non replacement free calculus into a weakly replacement free one. As a consequence of our encodability results, we get that many calculi equipped with priority are not replacement free and hence are not encodable into mainstream calculi like CCS and pi-calculus, that instead are strongly replacement free. We also prove that variants of pi-calculus with match among names, pattern matching or polyadic synchronization are only weakly replacement free, hence they are separated both from process calculi with priority and from mainstream calculi.Comment: In Proceedings EXPRESS'10, arXiv:1011.601

    Central nervous system metastases from castration-resistant prostate cancer in the docetaxel era.

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    Central nervous system (brain or leptomeningeal) metastases (BLm) are considered rare in castration-resistant prostate cancer (CRPC) patients. Now that docetaxel has become the reference drug for first-line treatment of CRPC, patients whose disease is not controlled by hormonal manipulations may live much longer than before and have higher risk of developing BLm. We retrospectively reviewed the records of all patients with CRPC attending our centres from 2002 to 2010, and identified all of those who were diagnosed as having BLm and received (or were considered to have been eligible to receive) docetaxel-based treatment. We identified 31 cases of BLm (22 brain metastases and 9 leptomeningeal metastases) with an incidence of 3.3%. BLm-free survival was 43.5 months, and survival after BLm discovery was 4 months. With six patients surviving for more than 1 year after developing BLm, the projected 1-year BL-S rate was 25.8%. The findings of our study may be relevant in clinical practice as they indicate that incidence of BLm in CRPC patients in the docetaxel era seems to be higher than in historical reports, meaning that special attention should be paid to the appearance of neurological symptoms in long-term CRPC survivors because they may be related to BLm

    GeantV: Results from the prototype of concurrent vector particle transport simulation in HEP

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    Full detector simulation was among the largest CPU consumer in all CERN experiment software stacks for the first two runs of the Large Hadron Collider (LHC). In the early 2010's, the projections were that simulation demands would scale linearly with luminosity increase, compensated only partially by an increase of computing resources. The extension of fast simulation approaches to more use cases, covering a larger fraction of the simulation budget, is only part of the solution due to intrinsic precision limitations. The remainder corresponds to speeding-up the simulation software by several factors, which is out of reach using simple optimizations on the current code base. In this context, the GeantV R&D project was launched, aiming to redesign the legacy particle transport codes in order to make them benefit from fine-grained parallelism features such as vectorization, but also from increased code and data locality. This paper presents extensively the results and achievements of this R&D, as well as the conclusions and lessons learnt from the beta prototype.Comment: 34 pages, 26 figures, 24 table

    Choreography Rehearsal ⋆

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    Abstract. We propose a methodology for statically predicting the possible interaction patterns of services within a given choreography. We focus on choreographies exploiting the event notification paradigm to manage service interactions. Control Flow Analysis techniques statically approximate which events can be delivered to match the choreography constraints and how the multicast groups can be optimised to handle event notification within the service choreography.

    Modelling the ARMv8 architecture, operationally: Concurrency and ISA

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    Copyright is held by the owner/author(s). In this paper we develop semantics for key aspects of the ARMv8 multiprocessor architecture: the concurrency model and much of the 64-bit application-level instruction set (ISA). Our goal is to clarify what the range of architecturally allowable behaviour is, and thereby to support future work on formal verification, analysis, and testing of concurrent ARM software and hardware. Establishing such models with high confidence is intrinsically difficult: it involves capturing the vendor's architectural intent, aspects of which (especially for concurrency) have not previously been precisely defined. We therefore first develop a concurrency model with a microarchitectural flavour, abstracting from many hardware implementation concerns but still close to hardware-designer intuition. This means it can be discussed in detail with ARM architects. We then develop a more abstract model, better suited for use as an architectural specification, which we prove sound w.r.t. the first. The instruction semantics involves further difficulties, handling the mass of detail and the subtle intensional information required to interface to the concurrency model. We have a novel ISA description language, with a lightweight dependent type system, letting us do both with a rather direct representation of the ARM reference manual instruction descriptions. We build a tool from the combined semantics that lets one explore, either interactively or exhaustively, the full range of architecturally allowed behaviour, for litmus tests and (small) ELF executables. We prove correctness of some optimisations needed for tool performance. We validate the models by discussion with ARM staff, and by comparison against ARM hardware behaviour, for ISA single-instruction tests and concurrent litmus tests.This work was partly funded by the EPSRC Programme Grant REMS: Rigorous Engineering for Mainstream Systems, EP/K008528/1, the Scottish Funding Council (SICSA Early Career Industry Fellowship, Sarkar), an ARM iCASE award (Pulte), and ANR grant WMC (ANR-11-JS02-011, Maranget)
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