73,501 research outputs found

    Orientation of non-spherical particles in an axisymmetric random flow

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    The dynamics of non-spherical rigid particles immersed in an axisymmetric random flow is studied analytically. The motion of the particles is described by Jeffery's equation; the random flow is Gaussian and has short correlation time.The stationary probability density function of orientations is calculated exactly. Four regimes are identified depending on the statistical anisotropy of the flow and on the geometrical shape of the particle. If {\lambda} is the axis of symmetry of the flow, the four regimes are: rotation about {\lambda}, tumbling motion between {\lambda} and -{\lambda}, combination of rotation and tumbling, and preferential alignment with a direction oblique to {\lambda}.Comment: 18 pages, 8 figure

    The origin of beach sediments on the North Queensland coast

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    Petrographic and granulometric analyses of North Queensland beach sediments indicate their affinity with sediments delivered to the coast by rivers, and it is shown that the beaches are largely derived from fluvial sediment reworked, sorted and distributed by the dominant south-easterly waves in coastal waters. Beach sediments are generally quartzose, with subordinate felspars and admixtures of coralline sediment near fringing reefs and lithic material near river mouths and rocky shore sectors. The prevailing northerly drift of shore sediment is reduced, and locally reversed, on sectors sheltered from the dominant south-easterly waves by headlands, reefs and islands. Variations in beach sediment are related to wave conditions, distance from river-mouth sources, and patterns of drift. Four Mile Beach, near Port Douglas, is identified as anomalous in its morphological and sedimentological characteristics. It has been cut off from former sources of sediment, both fluvial and longshore, as a result of reef extension around the mouth of Mowbray River, and is now essentially a relict beach system attaining sedimentological maturity

    A lexical database tool for quantitative phonological research

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    A lexical database tool tailored for phonological research is described. Database fields include transcriptions, glosses and hyperlinks to speech files. Database queries are expressed using HTML forms, and these permit regular expression search on any combination of fields. Regular expressions are passed directly to a Perl CGI program, enabling the full flexibility of Perl extended regular expressions. The regular expression notation is extended to better support phonological searches, such as search for minimal pairs. Search results are presented in the form of HTML or LaTeX tables, where each cell is either a number (representing frequency) or a designated subset of the fields. Tables have up to four dimensions, with an elegant system for specifying which fragments of which fields should be used for the row/column labels. The tool offers several advantages over traditional methods of analysis: (i) it supports a quantitative method of doing phonological research; (ii) it gives universal access to the same set of informants; (iii) it enables other researchers to hear the original speech data without having to rely on published transcriptions; (iv) it makes the full power of regular expression search available, and search results are full multimedia documents; and (v) it enables the early refutation of false hypotheses, shortening the analysis-hypothesis-test loop. A life-size application to an African tone language (Dschang) is used for exemplification throughout the paper. The database contains 2200 records, each with approximately 15 fields. Running on a PC laptop with a stand-alone web server, the `Dschang HyperLexicon' has already been used extensively in phonological fieldwork and analysis in Cameroon.Comment: 7 pages, uses ipamacs.st

    PSR J2032+4127, the counterpart of TeV J2032+4130? Multiwavelength Monitoring of the Approach to Periastron

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    PSR J2032+4127 has recently been identified as being in a long period (45-50 years) binary in a highly eccentric orbit with the Be star MT91 213. Periastron is due to occur in November 2017 and this rare occurrence has prompted a multiwavelength monitoring campaign to determine if the system is a gamma-ray binary, and, if so, to study what would be only the second gamma-ray binary with a known compact object. In the same direction as TeV J2032+4130, gamma-ray emission from this binary system could be related to the extended very high energy gamma-ray emission from that region. As part of this monitoring, observations are being conducted by Swift, Fermi-LAT and VERITAS. We present the status of those observations, preliminary results and the plan for continued monitoring through periastron.Comment: 8 Pages, 4 figures, 1 table. In Proceedings of the 35th International Cosmic Ray Conference (ICRC 2017), Busan (South Korea

    An ‘objective-centred’ approach to course redesign: using learning objectives to integrate e-learning

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    This article describes the process of integrating e-learning into the M-level research methods course Research Synthesis for Policy and Practice. It explores an ‘objective-centred’ approach to course redesign. This entails using learning objectives as the basis for developing online activities and integrating technological tools. This article describes what this ‘objectives approach’ meant in practice and illustrates the importance of learning objectives for the redesign process. Embedding elearning into the course provides new opportunities to meet existing objectives in an innovative, and hopefully more effective, way. Technological tools provide the scope to extend and develop new learning objectives to better meet the needs of students. Whilst objectives are central to the redesign, the article highlights the significant role played by other types of knowledge, namely tutor experience, student views and research
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