351 research outputs found

    The evaluation challenge

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    For years writers concerned with information literacy (IL) – essentially the knowledge, skills and understanding needed to find and use information effectively – have stressed the importance of learners evaluating the material with which they come into contact whilst searching. As many commentators explain, the need to make sound judgements has become especially important today, since so much information searching now involves the World Wide Web. The evaluative framework proposed in this article was designed with the aim of helping to narrow the gap between discoveries emerging from research and the teaching of IL

    Young people and the evaluation of information on the World Wide Web: Principles, practice and beliefs

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    A recurrent theme in LIS literature is the tendency of young people not to evaluate rigorously the information with which they come into contact. Although many information literacy models stress the need to take a critical approach, the reality of behaviour is often very different. Recent research conducted in an English high school has explored the importance that teenagers attach to ten particular evaluative criteria. 149 youngsters contributed data via an online questionnaire. Participants felt that information on the Web should be current/topical, free from spelling and grammatical errors and easily verifiable elsewhere but authorship was much less of a priority to them. The findings are likely to be of special relevance to information literacy teachers who are defining priorities for their own programmes

    Facilitating pupil thinking about information literacy

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    Whilst information literacy is frequently taught through the imposition on learners of an established framework, this paper suggests a different approach by taking a lead from James Herring’s ideas. Specifically, it provides guidance to school-based information professionals who would like to encourage their pupils to devise their own flexible, information literacy models which are unique to them. Drawing on existing material in information science and wider thought, it proposes areas for coverage and considers how information professionals may support the dynamic process of model construction. It is recommended that those who are intent on facilitating the creation of personal information literacy models help pupils to identify the roles they take on in their lives, to reflect on the information needs that result, to ascertain the information they require in particular situations, to explore their information-seeking activities, to consider means by which information can be captured and to give thought as to how the information they have accessed may be used. This framework is, however, by no means rigid and readers are, of course, free to make their own adjustments

    Synthesis And Stereochemistry Of Dimethylindium (iii) Derivatives

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    Thermodynamically stable lithium silicides and germanides from density-functional theory calculations

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    Density-functional-theory (DFT) calculations have been performed on the Li-Si and Li-Ge systems. Lithiated Si and Ge, including their metastable phases, play an important technological r\^ole as Li-ion battery (LIB) anodes. The calculations comprise structural optimisations on crystal structures obtained by swapping atomic species to Li-Si and Li-Ge from the X-Y structures in the International Crystal Structure Database, where X={Li,Na,K,Rb,Cs} and Y={Si,Ge,Sn,Pb}. To complement this at various Li-Si and Li-Ge stoichiometries, ab initio random structure searching (AIRSS) was also performed. Between the ground-state stoichiometries, including the recently found Li17_{17}Si4_{4} phase, the average voltages were calculated, indicating that germanium may be a safer alternative to silicon anodes in LIB, due to its higher lithium insertion voltage. Calculations predict high-density Li1_1Si1_1 and Li1_1Ge1_1 P4/mmmP4/mmm layered phases which become the ground state above 2.5 and 5 GPa respectively and reveal silicon and germanium's propensity to form dumbbells in the Lix_xSi, x=2.333.25x=2.33-3.25 stoichiometry range. DFT predicts the stability of the Li11_{11}Ge6_6 CmmmCmmm, Li12_{12}Ge7_7 PnmaPnma and Li7_7Ge3_3 P3212P32_12 phases and several new Li-Ge compounds, with stoichiometries Li5_5Ge2_2, Li13_{13}Ge5_5, Li8_8Ge3_3 and Li13_{13}Ge4_4.Comment: 10 pages, 5 figure

    Product innovation in a new technology based firm

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    This thesis examines the "state of the art" of product innovation in new technology In the UK. The roles in innovation attributed to small and large firms are examined. Growing attention is being focused upon the small firm sector as a seedbed for Innovation and government policy has been changing to encourage the entrepreneurial new technology based firm (NTBF). The novel perspective of this research results from working in such a firm. It provides a longitudinal study of the management of innovation in conjunction with the corporate strategy of the firm. Given that the researcher was a participant and observer in the firm studied, the research is akin to action research in methodology but is better described as grounded theory. Theoretical concepts are drawn from the prescriptive literature describing corporate strategy, and from the empirical literature which has evaluated new product success and failure. Models of the Innovation process are discussed and appropriate strategies and reasons for product innovation failure in NTBFs are described. The strategy, structure and new product development progress of the company are examined, using both the researcher's observations and company documents. This provides information on the methods and practices adopted for product innovation in a NTBF. The thesis analyses the performance of the firm In terms of product innovation. The models and strategies derived from the literature are then tested in the light of the experience of the company. Conclusions are drawn regarding strategies for innovation in NTBFs and about the innovation process in general. The importance of a NTBF adopting a synergistic strategy is shown. Links are established between the existence of synergy in the strategy and coupling in the management of innovation. Innovation is shown to be a laterally interdisciplinary exercise and therefore the "pipeline model" Is criticised. Finally a set of guidelines Is produced for the managers of NTBFs

    Hydrogen/nitrogen/oxygen defect complexes in silicon from computational searches

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    Point defect complexes in crystalline silicon composed of hydrogen, nitrogen, and oxygen atoms are studied within density-functional theory (DFT). Ab initio Random Structure Searching (AIRSS) is used to find low-energy defect structures. We find new lowest-energy structures for several defects: the triple-oxygen defect, {3O}, triple oxygen with a nitrogen atom, {N, 3O}, triple nitrogen with an oxygen atom, {3N,O}, double hydrogen and an oxygen atom, {2H,O}, double hydrogen and oxygen atoms, {2H,2O} and four hydrogen/nitrogen/oxygen complexes, {H,N,O}, {2H,N,O}, {H,2N,O} and {H,N,2O}. We find that some defects form analogous structures when an oxygen atom is replaced by a NH group, for example, {H,N,2O} and {3O}, and {H,N} and {O}. We compare defect formation energies obtained using different oxygen chemical potentials and investigate the relative abundances of the defects.Comment: 9 pages, 13 figure

    Energetics of hydrogen/lithium complexes in silicon analyzed using the Maxwell construction

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    We have studied hydrogen/lithium complexes in crystalline silicon using density-functional-theory methods and the ab initio random structure searching (AIRSS) method for predicting structures. A method based on the Maxwell construction and convex hull diagrams is introduced which gives a graphical representation of the relative stabilities of point defects in a crystal and enables visualization of the changes in stability when the chemical potentials are altered. We have used this approach to study lithium and hydrogen impurities in silicon, which models aspects of the anode material in the recently-suggested lithium-ion batteries. We show that hydrogen may play a role in these anodes, finding that hydrogen atoms bind to three-atom lithium clusters in silicon, forming stable {H,3Li} and {2H,3Li} complexes, while the {H,2Li} complex is almost stable.Comment: (5 pages, 4 figures

    Lithiation of silicon via lithium Zintl-defect complexes

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    An extensive search for low-energy lithium defects in crystalline silicon using density-functional-theory methods and the ab initio random structure searching (AIRSS) method shows that the four-lithium-atom substitutional point defect is exceptionally stable. This defect consists of four lithium atoms with strong ionic bonds to the four under-coordinated atoms of a silicon vacancy defect, similar to the bonding of metal ions in Zintl phases. This complex is stable over a range of silicon environments, indicating that it may aid amorphization of crystalline silicon and form upon delithiation of the silicon anode of a Li-ion rechargeable battery.Comment: 4 pages, 3 figure
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