4,574 research outputs found

    Designing for tacit learning: an investigation of design strategies for multimedia supported learning in the crafts

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    There is an increasing interest and activity in the design of interactive multimedia to support learning in all fields of education and training. However, most of the theory to support such developments is concerned with learning explicit knowledge and there is little guidance available to designers of material for learning in areas with an element of tacit knowledge such as craft skills. This paper describes the foundation work for a long-term project concerned with learning in traditional rural crafts but with the intention to provide a methodological framework for the design of multimedia-based learning in all areas of craft knowledge. A review of established theory of learning and the use of multimedia for learning in areas of explicit knowledge indicates some important basic principles, for example the need to understand the interaction between the teacher and learner in the context of the subject being taught and the need for clear narrative structures to avoid students becoming "lost" in the multiple pathways of interactive media. Observational studies of learning using educational video in a craft context and a study of an experienced craftsman/teacher teaching a group of learners, complemented by study of learning in related contexts, have allowed problems and issues to be identified and design strategies to be developed. While these are provisional they provide an overview of the design problems and have been used to plan a programme of experimental design and evaluation to test and develop principles of effective multimedia design for craft learning. </p

    Micro-Sigmoids as Progenitors of Coronal Jets - Is Eruptive Activity Self-Similarly Multi-Scaled?

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    Observations from the X-ray telescope (XRT) on Hinode are used to study the nature of X-ray bright points, sources of coronal jets. Several jet events in the coronal holes are found to erupt from small-scale, S-shaped bright regions. This finding suggests that coronal micro-sigmoids may well be progenitors of coronal jets. Moreover, the presence of these structures may explain numerous observed characteristics of jets such as helical structures, apparent transverse motions, and shapes. In analogy to large-scale sigmoids giving rise to coronal mass ejections (CMEs), a promising future task would perhaps be to investigate whether solar eruptive activity, from coronal jets to CMEs, is self-similar in terms of properties and instability mechanisms.Comment: 8 pages, 5 figures, 1 tabl

    A middleware for a large array of cameras

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    Large arrays of cameras are increasingly being employed for producing high quality image sequences needed for motion analysis research. This leads to the logistical problem with coordination and control of a large number of cameras. In this paper, we used a lightweight multi-agent system for coordinating such camera arrays. The agent framework provides more than a remote sensor access API. It allows reconfigurable and transparent access to cameras, as well as software agents capable of intelligent processing. Furthermore, it eases maintenance by encouraging code reuse. Additionally, our agent system includes an automatic discovery mechanism at startup, and multiple language bindings. Performance tests showed the lightweight nature of the framework while validating its correctness and scalability. Two different camera agents were implemented to provide access to a large array of distributed cameras. Correct operation of these camera agents was confirmed via several image processing agents

    Observational Evidence for Coronal Twisted Flux Rope

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    Multi-instrument data sets of NOAA AR10938 on Jan. 16, 2007, (e.g., {\emph{Hinode}}, {\it{STEREO}}, {\it{GOES}}, {\it{MLSO}} and {\it{ISOON}} Hα\alpha) are utilized to study the fine structure and evolution of a magnetic loop system exhibiting multiple crossing threads, whose arrangement and individual shapes are very suggestive of individual field lines in a flux rope. The footpoints of the magnetic threads are closely rooted into pores and plage areas. A C-class flare recorded by {\it{GOES}} at approximately 2:35 UT near one of the footpoints of the multi-thread system (along with a wisp of loop material shown by EUV data) led to the brightening of the magnetic structure revealing its fine structure with several threads that indicate a high degree of linking (suggesting a left-handed helical pattern as shown by the filament structure formed later-on). EUV observations by {\emph{Hinode}}/EIS of hot spectral lines at 2:46 UT show a complex structure of coronal loops. The same features were observed about 20 minutes later in X-ray images from {\emph{Hinode}}/XRT and about 30 minutes further in EUV images of {\it{STEREO}}/SECCHI/EUVI with much better resolution. Hα\alpha and 304 {\AA} images revealed the presence of several filament fibrils in the same area. They evolved a few hours later into a denser structure seemingly showing helical structure, which persistently lasted for several days forming a segment of a larger scale filament. The present observations provide an important indication for a flux robe as a precursor of a solar filament.Comment: 13 pages, 4 figure

    The Resonance Peak in Sr2_2RuO4_4: Signature of Spin Triplet Pairing

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    We study the dynamical spin susceptibility, χ(q,ω)\chi({\bf q}, \omega), in the normal and superconducting state of Sr2_2RuO4_4. In the normal state, we find a peak in the vicinity of Qi(0.72π,0.72π){\bf Q}_i\simeq (0.72\pi,0.72\pi) in agreement with recent inelastic neutron scattering (INS) experiments. We predict that for spin triplet pairing in the superconducting state a {\it resonance peak} appears in the out-of-plane component of χ\chi, but is absent in the in-plane component. In contrast, no resonance peak is expected for spin singlet pairing.Comment: 4 pages, 4 figures, final versio

    MACiE: a database of enzyme reaction mechanisms.

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    SUMMARY: MACiE (mechanism, annotation and classification in enzymes) is a publicly available web-based database, held in CMLReact (an XML application), that aims to help our understanding of the evolution of enzyme catalytic mechanisms and also to create a classification system which reflects the actual chemical mechanism (catalytic steps) of an enzyme reaction, not only the overall reaction. AVAILABILITY: http://www-mitchell.ch.cam.ac.uk/macie/.EPSRC (G.L.H. and J.B.O.M.), the BBSRC (G.J.B. and J.M.T.—CASE studentship in association with Roche Products Ltd; N.M.O.B. and J.B.O.M.—grant BB/C51320X/1), the Chilean Government’s Ministerio de Planificacio´n y Cooperacio´n and Cambridge Overseas Trust (D.E.A.) for funding and Unilever for supporting the Centre for Molecular Science Informatics.application note restricted to 2 printed pages web site: http://www-mitchell.ch.cam.ac.uk/macie

    Current Helicity and Twist as Two Indicators of The Mirror Asymmetry of solar Magnetic Fields

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    A comparison between the two tracers of magnetic field mirror asymmetry in solar active regions, twist and current helicity, is presented. It is shown that for individual active regions these tracers do not possess visible similarity while averaging by time over the solar cycle, or by latitude, reveals similarities in their behaviour. The main property of the dataset is anti-symmetry over the solar equator. Considering the evolution of helical properties over the solar cycle we find signatures of a possible sign change at the beginning of the cycle, though more systematic observational data are required for a definite confirmation. We discuss the role of both tracers in the context of the solar dynamo theory.Comment: 14 pages, 6 figure
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