12,358 research outputs found

    Secondary literacy across the curriculum: Challenges and possibilities

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    This paper discusses the challenges and possibilities attendant upon successfully implementing literacy across the curriculum initiatives – or ‘school language policies’ as they have come to be known - particularly at the secondary or high school level. It provides a theoretical background to these issues, exploring previous academic discussions of school language policies, and highlights key areas of concern as well as opportunity with respect to school implementation of such policies. As such, it provides a necessary conceptual background to the subsequent papers in this special issue, which focus upon the Secondary Schools’ Literacy Initiative (SSLI) – a New Zealand funded programme that aims to establish cross-curricular language and literacy policies in secondary schools

    Eigenvalue Separation in Some Random Matrix Models

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    The eigenvalue density for members of the Gaussian orthogonal and unitary ensembles follows the Wigner semi-circle law. If the Gaussian entries are all shifted by a constant amount c/Sqrt(2N), where N is the size of the matrix, in the large N limit a single eigenvalue will separate from the support of the Wigner semi-circle provided c > 1. In this study, using an asymptotic analysis of the secular equation for the eigenvalue condition, we compare this effect to analogous effects occurring in general variance Wishart matrices and matrices from the shifted mean chiral ensemble. We undertake an analogous comparative study of eigenvalue separation properties when the size of the matrices are fixed and c goes to infinity, and higher rank analogues of this setting. This is done using exact expressions for eigenvalue probability densities in terms of generalized hypergeometric functions, and using the interpretation of the latter as a Green function in the Dyson Brownian motion model. For the shifted mean Gaussian unitary ensemble and its analogues an alternative approach is to use exact expressions for the correlation functions in terms of classical orthogonal polynomials and associated multiple generalizations. By using these exact expressions to compute and plot the eigenvalue density, illustrations of the various eigenvalue separation effects are obtained.Comment: 25 pages, 9 figures include

    Traffic Network Optimum Principle - Minimum Probability of Congestion Occurrence

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    We introduce an optimum principle for a vehicular traffic network with road bottlenecks. This network breakdown minimization (BM) principle states that the network optimum is reached, when link flow rates are assigned in the network in such a way that the probability for spontaneous occurrence of traffic breakdown at one of the network bottlenecks during a given observation time reaches the minimum possible value. Based on numerical simulations with a stochastic three-phase traffic flow model, we show that in comparison to the well-known Wardrop's principles the application of the BM principle permits considerably greater network inflow rates at which no traffic breakdown occurs and, therefore, free flow remains in the whole network.Comment: 22 pages, 6 figure

    Systems, interactions and macrotheory

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    A significant proportion of early HCI research was guided by one very clear vision: that the existing theory base in psychology and cognitive science could be developed to yield engineering tools for use in the interdisciplinary context of HCI design. While interface technologies and heuristic methods for behavioral evaluation have rapidly advanced in both capability and breadth of application, progress toward deeper theory has been modest, and some now believe it to be unnecessary. A case is presented for developing new forms of theory, based around generic “systems of interactors.” An overlapping, layered structure of macro- and microtheories could then serve an explanatory role, and could also bind together contributions from the different disciplines. Novel routes to formalizing and applying such theories provide a host of interesting and tractable problems for future basic research in HCI

    On the Prior Sensitivity of Thompson Sampling

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    The empirically successful Thompson Sampling algorithm for stochastic bandits has drawn much interest in understanding its theoretical properties. One important benefit of the algorithm is that it allows domain knowledge to be conveniently encoded as a prior distribution to balance exploration and exploitation more effectively. While it is generally believed that the algorithm's regret is low (high) when the prior is good (bad), little is known about the exact dependence. In this paper, we fully characterize the algorithm's worst-case dependence of regret on the choice of prior, focusing on a special yet representative case. These results also provide insights into the general sensitivity of the algorithm to the choice of priors. In particular, with pp being the prior probability mass of the true reward-generating model, we prove O(T/p)O(\sqrt{T/p}) and O((1−p)T)O(\sqrt{(1-p)T}) regret upper bounds for the bad- and good-prior cases, respectively, as well as \emph{matching} lower bounds. Our proofs rely on the discovery of a fundamental property of Thompson Sampling and make heavy use of martingale theory, both of which appear novel in the literature, to the best of our knowledge.Comment: Appears in the 27th International Conference on Algorithmic Learning Theory (ALT), 201

    The open cluster NGC 6520 and the nearby dark molecular cloud Barnard 86

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    Wide field BVI photometry and 12^{12}CO(1→\to0) observations are presen ted in the region of the open cluster NGC 6520 and the dark molecular cloud Barnard~86. From the analysis of the optical data we find that the cluster is rather compact, with a radius of 1.0±\pm0.5 arcmin, smaller than previous estimates. The cluster age is 150±\pm50 Myr and the reddening EB−V_{B-V}=0.42±\pm0.10. The distance from the Sun is estimated to be 1900±\pm100 pc, and it is larger than previous estimates. We finally derive basic properties of the dark nebula Barnard 86 on the assumption that it lies at the same distance of the cluster.Comment: 21 pages, 8 eps figures (a few degraded in resolution), accepted for publication in the Astronomical Journa

    Kajian Refraksi-Difraksi Dan Transformasi Penjalaran Gelombang Laut Di Perairan Pantai Tapak Paderi Kota Bengkulu

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    Pantai Tapak Paderi Kota Bengkulu merupakan pantai yang telah beralih fungsi dari kawasan pelabuhan menjadi kawasan pantai wisata akibat kurangnya informasi terkait penjalaran gelombang laut di perairannya. Tujuan penelitian ini untuk mendapatkan informasi transformasi penjalaran gelombang terkait refraksi dan difraksi gelombang di perairan Tapak Paderi Kota Bengkulu berdasarkan jalur pengamatan. Proses pengolahan data terdiri dari konversi gelombang per musim dari data angin 10 tahun dan proses model simulasi penjalaran gelombang menggunakan BOUSS2D dari program Surface Water Modeling System 11. Hasil pengukuran lapangan selama tiga hari di perairan Tapak Paderi menghasilkan tinggi signifikan 1,6 m dan periode signifikan 7,75 s. Hasil konversi angin menggunakan metode SMB mengasilkan resume data gelombang per musim selama sepuluh tahun. Gelombang signifikan tertinggi di perairan Tapak Paderi terjadi pada musim Timur dan peralihan II, masing-masing memiliki tinggi signifikan 2,23 m dan 2,0 m dengan periode signifikan 7,12 s dan 7,0. Gelombang di perairan Tapak Paderi memiliki dua arah datang dominan, yakni gelombang datang dari kelompok fetch barat laut dan kelompok fetch selatan. Hasil analisis simulasi model berdasarkan jalur pengamatan menunjukkan bahwa gelombang mengalami refraksi di jalur pengamatan 1, mengalami difraksi setelah adanya Gosong Patasembilan di jalur pengamatan 2, mengalami difraksi setelah adanya anak Gosong Patasembilan dan konvergensi gelombang pada Tanjung Pantai Tapak Paderi di jalur pengamatan 3, mengalami konvergensi pada daerah tanjung dan divergensi pada daerah teluk di jalur pengamatan 4. Sedangkan untuk tinggi gelombang terendah sebesar 0,29 m terjadi pada musim peralihan II pada titik pengamatan di belakang ujung bangunan pantai Tapak Paderi

    Rethinking the patient: using Burden of Treatment Theory to understand the changing dynamics of illness

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    <b>Background</b> In this article we outline Burden of Treatment Theory, a new model of the relationship between sick people, their social networks, and healthcare services. Health services face the challenge of growing populations with long-term and life-limiting conditions, they have responded to this by delegating to sick people and their networks routine work aimed at managing symptoms, and at retarding - and sometimes preventing - disease progression. This is the new proactive work of patient-hood for which patients are increasingly accountable: founded on ideas about self-care, self-empowerment, and self-actualization, and on new technologies and treatment modalities which can be shifted from the clinic into the community. These place new demands on sick people, which they may experience as burdens of treatment.<p></p> <b>Discussion</b> As the burdens accumulate some patients are overwhelmed, and the consequences are likely to be poor healthcare outcomes for individual patients, increasing strain on caregivers, and rising demand and costs of healthcare services. In the face of these challenges we need to better understand the resources that patients draw upon as they respond to the demands of both burdens of illness and burdens of treatment, and the ways that resources interact with healthcare utilization.<p></p> <b>Summary</b> Burden of Treatment Theory is oriented to understanding how capacity for action interacts with the work that stems from healthcare. Burden of Treatment Theory is a structural model that focuses on the work that patients and their networks do. It thus helps us understand variations in healthcare utilization and adherence in different healthcare settings and clinical contexts

    The Clumping Transition in Niche Competition: a Robust Critical Phenomenon

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    We show analytically and numerically that the appearance of lumps and gaps in the distribution of n competing species along a niche axis is a robust phenomenon whenever the finiteness of the niche space is taken into account. In this case depending if the niche width of the species σ\sigma is above or below a threshold σc\sigma_c, which for large n coincides with 2/n, there are two different regimes. For σ>sigmac\sigma > sigma_c the lumpy pattern emerges directly from the dominant eigenvector of the competition matrix because its corresponding eigenvalue becomes negative. For σ</−sigmac\sigma </- sigma_c the lumpy pattern disappears. Furthermore, this clumping transition exhibits critical slowing down as σ\sigma is approached from above. We also find that the number of lumps of species vs. σ\sigma displays a stair-step structure. The positions of these steps are distributed according to a power-law. It is thus straightforward to predict the number of groups that can be packed along a niche axis and it coincides with field measurements for a wide range of the model parameters.Comment: 16 pages, 7 figures; http://iopscience.iop.org/1742-5468/2010/05/P0500
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