66 research outputs found

    Properties of Multimode Optical Epoxy Polymer Waveguides Deposited on Silicon and TOPAS Substrate

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    The paper reports on the fabrication and characterization of multimode polymer optical waveguides. Epoxy polymer EpoCore was used as the waveguide core material and EpoClad was used as a cladding and cover protection layer. The design of the waveguides was schemed for geometric dimensions of core 50 μm and for 850 nm and 1310 nm wavelengths. Proposed shapes of the waveguides were fabricated by standard photolithography process. Optical losses of the planar waveguides were measured by the fibre probe technique at 632.8 nm and 964 nm. Propagation optical loss measurements for rectangular waveguides were done by using the cut-back method and the best samples had optical losses lower than 0.53 dB/cm at 650 nm, 850 nm and 1310 nm

    Authenticity, Culture and Language Learning

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    In philosophy, authenticity has been used with two meanings: one entails the notion of correspondence; the other entails the notion of genesis (Cooper, 1983: 15). As in certain branches of philosophy, language teaching has perhaps clung too long to the first of these notions of authenticity at the expense of the other. This paper reviews four key conceptualisations of authenticity which have emerged in the field of applied linguistics: text authenticity, authenticity of language competence, learner authenticity and classroom authenticity. If any of these types of authenticity is couched exclusively in terms of one usage or the other, it can lead to an impoverishment and objectification of the experience of language learning. Text authenticity can lead to a poverty of language; authenticity of competence can lead to a poverty of performance; learner authenticity can lead to a poverty of interpretation; classroom authenticity can lead to a poverty of communication. This paper proposes that a pedagogy of intercultural communication be informed by a more hybrid view of authenticity as a process of subjectification, derived from the Heideggerian concept of self-concern

    The RESET project: constructing a European tephra lattice for refined synchronisation of environmental and archaeological events during the last c. 100 ka

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    This paper introduces the aims and scope of the RESET project (. RESponse of humans to abrupt Environmental Transitions), a programme of research funded by the Natural Environment Research Council (UK) between 2008 and 2013; it also provides the context and rationale for papers included in a special volume of Quaternary Science Reviews that report some of the project's findings. RESET examined the chronological and correlation methods employed to establish causal links between the timing of abrupt environmental transitions (AETs) on the one hand, and of human dispersal and development on the other, with a focus on the Middle and Upper Palaeolithic periods. The period of interest is the Last Glacial cycle and the early Holocene (c. 100-8 ka), during which time a number of pronounced AETs occurred. A long-running topic of debate is the degree to which human history in Europe and the Mediterranean region during the Palaeolithic was shaped by these AETs, but this has proved difficult to assess because of poor dating control. In an attempt to move the science forward, RESET examined the potential that tephra isochrons, and in particular non-visible ash layers (cryptotephras), might offer for synchronising palaeo-records with a greater degree of finesse. New tephrostratigraphical data generated by the project augment previously-established tephra frameworks for the region, and underpin a more evolved tephra 'lattice' that links palaeo-records between Greenland, the European mainland, sub-marine sequences in the Mediterranean and North Africa. The paper also outlines the significance of other contributions to this special volume: collectively, these illustrate how the lattice was constructed, how it links with cognate tephra research in Europe and elsewhere, and how the evidence of tephra isochrons is beginning to challenge long-held views about the impacts of environmental change on humans during the Palaeolithic. © 2015 Elsevier Ltd.RESET was funded through Consortium Grants awarded by the Natural Environment Research Council, UK, to a collaborating team drawn from four institutions: Royal Holloway University of London (grant reference NE/E015905/1), the Natural History Museum, London (NE/E015913/1), Oxford University (NE/E015670/1) and the University of Southampton, including the National Oceanography Centre (NE/01531X/1). The authors also wish to record their deep gratitude to four members of the scientific community who formed a consultative advisory panel during the lifetime of the RESET project: Professor Barbara Wohlfarth (Stockholm University), Professor Jørgen Peder Steffensen (Niels Bohr Institute, Copenhagen), Dr. Martin Street (Romisch-Germanisches Zentralmuseum, Neuwied) and Professor Clive Oppenheimer (Cambridge University). They provided excellent advice at key stages of the work, which we greatly valued. We also thank Jenny Kynaston (Geography Department, Royal Holloway) for construction of several of the figures in this paper, and Debbie Barrett (Elsevier) and Colin Murray Wallace (Editor-in-Chief, QSR) for their considerable assistance in the production of this special volume.Peer Reviewe

    Glosas de la Ciudad

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    Podhradem Interstadial; A critical review of the middle and late MIS 3 (Denekamp, Hengelo) in Moravia, Czech Republic

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    Knowledge of global climatic fluctuations in the last glacial period has been instrumental for understanding evolution of the landscape and human behavior. Regional environmental responses to these fluctuations are influenced by many factors and their identification at the regional level usually results in local chronostratigraphic schemes. The term Podhradem Interstadial was introduced to the scientific community in 1966 on the basis of the results of an interdisciplinary excavation at Pod Hradem Cave in the Moravian Karst (Czech Republic). Brown soil horizons preserved in the upper part of the section were interpreted as evidence for a warmer period in the last glacial period. The upper part of this soil complex contained fauna remains and lithic artefacts indirectly dated to the time range 28.2-333 C-14 ka BP. Although based on contemporary state of knowledge, the Podhradem Interstadial had no stratigraphic equivalent in loess profiles of former Czechoslovakia and Lower Austria, the term was occasionally used in the European literature. The new interdisciplinary excavations of Pod Hradem Cave (2011-2016) yielded new data, which we use to re-evaluate the concept of the Podhradem Interstadial. In light of the new results, it seems that the original definition of Podhradem Interstadial has a number of problems. It does not fulfill stratigraphic standards and it is evident that the contemporaneous sediments differ lithologically in different parts of the cave. Furthermore, when we take into account the current availability of sophisticated climatostratigraphic schemes for the MIS 3 period, the continuing use of the Podhradem Interstadial should be considered redundant.This project was funded from the SoMoPro under the European Community (FP/2007-2013 - Grant Agreement No. 229603). The research was also co-financed by the South Moravian Region and the Department of Anthropology, Masaryk University, by the internal program of the Institute of Geology ASCR in Prague No. RVO 67985831. This article was also financially supported by the Ministry of Culture, Czech Republic by institutional financing of long-term conceptual development of the research institution (the Moravian Museum, MK000094862)

    Effect of transcutaneous electrical nerve stimulation on onset of axillary plexus block

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    We examined the effect of high frequency transcutaneous electrical nerve stimulation on the onset of brachial plexus block. Three groups of patients scheduled for surgery of the hand had a local anaesthetic block performed with 40 ml mepivacaine 1.5% using the axillary approach. After injection of the local anaesthetic transcutaneous electrical nerve stimulation was applied for 15 min either to the median nerve or the ulnar nerve; no stimulation was applied in the control group. Before and for 45 min after, the injection of local anaesthetic touch perception, pin prick, motor strength and skin temperature were tested by a blinded investigator in the areas supplied by the median, musculocutaneous, radial and ulnar nerves. There were no differences in the onset of block between the groups. Thus, the frequency-dependent action of local anaesthetics could not be demonstrate
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