8,426 research outputs found
The evolution of a national research plan for computers in education in The Netherlands
This paper describes the evolution of a national research plan for computers and education in The Netherlands. This approach was initiated in 1983 and includes two phases: one from 1984 until 1988 and one from 1989 until 1992. The paper describes the research plans for the second phase, based upon the experiences of the first, and draws some general conclusions about the development of national research plans for computers in education
Prediction of thickness limits of ideal polar ultrathin films
Competition between electronic and atomic reconstruction is a constantly
recurring theme in transition-metal oxides. We use density functional theory
calculations to study this competition for a model system consisting of a thin
film of the polar, infinite-layer structure ACuO2 (A=Ca, Sr, Ba) grown on a
nonpolar, perovskite SrTiO3 substrate. A transition from the bulk planar
structure to a chain-type thin film accompanied by substantial changes to the
electronic structure is predicted for a SrCuO2 film fewer than five unit cells
thick. An analytical model explains why atomic reconstruction becomes more
favorable than electronic reconstruction as the film becomes thinner, and
suggests that similar considerations should be valid for other polar films
A simplified treatment of SiB's land surface albedo parameterization
The earlier presented surface albedo parameterization is simplified by assuming that the reflectance of direct solar radiation is a simple function of solar zenith angle. The function chosen contains three parameters that vary with vegetation type, greenness, and leaf area index. Tables of parameter values are presented. Using these tables, SiB's (Simple Biosphere model) absorbances of direct solar radiation can be reproduced with an average relative error of less than 0.5 percent. Finally, the direct reflectance function is integrated over zenith angle to produce an equation for the surface reflectance of diffuse radiation
Ceaseless, Unpredictable Creativity: Language as Technology
Notions like âbiolinguisticsâ have a trivial and a non-trivial interpretation. According to the trivial version, a cultural phenomenon like language is only based on our innate biological capacities. Language, in this view, is not a matter of biology per se but of applied biology, i.e. a form of technology. Under this interpretation, âbiolinguisticsâ is uncontroversial and trivial because all our cultural activities are grounded in our biology. According to the non-trivial interpretation, the concept of language can be sufficiently narrowly construed so that we can define a core capacity that is comparable to a biological organ (like the heart or the liver). Recently, it has become common to see this âfaculty of language in the narrow senseâ (FLN) as some abstract form of syntax characterized by recursive Merge. According to this article, only the trivial interpretation of âbiolinguisticsâ is correct. It does not make sense to define language in such a way that it excludes words. Words are human inventions and the necessary tools to give linguistic functionality to whatever biological capacities for recursive syntax we may have. Ultimately, this means that only âlexicalistâ versions of generative grammar can be correct. The agentive function assignment involved in the invention of words distinguishes language from bodily organs, which do not derive their functionality from human agency. More generally, cultural transparency of biological structures is rejected as an ideological form of Panglossian determinism and a denial of the âceaseless creativityâ and freedom coming with human agency
The distribution-free newsboy problem with resalable returns
We study the case of a catalogue/internet mail order retailer selling seasonal productsand receiving large numbers of commercial returns. Returned products arriving beforethe end of the selling season can be resold if there is sufficient demand. A single orderis placed before the season starts. Excess inventory at the end of the season is salvagedand all demands not met directly are lost. Since little historical information is available,it is impossible to determine the shape of the distribution of demand. Therefore, weanalyze the distribution-free newsboy problem with returns, in which only the mean andvariance of demand are assumed to be known. We derive a simple closed-form expressionfor the distribution-free order quantity, which we compare to the optimal order quantities whengross demand is assumed to be normal, lognormal or uniform. We find that the distribution-freeorder rule performs well in most realistic cases.inventory;product returns;distribution-free newsboy problem
Transverse-spin physics at RHIC/PHENIX
The PHENIX experiment at the Relativistic Heavy Ion Collider
(RHIC) probes the protonâs transverse-spin structure by measuring asymmetries in transversely polarized proton+proton collisions. The large single-transverse-spin
asymmetries observed at high-xF arise from either the Sivers effect, the Collins effect or higher-twist effects. PHENIX aims to disentangle these effects with complementary
measurements which provide sensitivity to each effect. This talk summarizes PHENIXâs current measurements and a planned upgrade to the experiment to better measure each effect
operating From Bastard Territory : Attitudes Toward The Motherland And The Colonial Self In Four Australian And Canadian Novelists
This thesis explores the question, inherent to the fiction of both Canada and Australia as settler colonies, of what images are used to depict the motherland, and how this depiction affects the new colony\u27s ability to create its sense of distinctiveness.;Examining critical studies of these national fictions in conjunction with those novels by four prominent Australian and Canadian authors which most closely examine the relationship between colony and Britain, this study uncovers four recurrent themes related to establishing a distinctive sense of self: the conception of opposing images of Britain and the new home; the experience of exile as a process leading to decreased insecurity; the establishment of a new relationship with the colonial landscape; and the necessity of discovering one\u27s personal power in the face of marginalization, by British or even colonial social norms.;The study next examines the four groups of texts individually, showing how each author emphasizes different aspects of these four foci, and demonstrating how alterations in the images of the motherland affect the characters\u27 views of how to achieve independence. An exploration of Boyd\u27s images of Britain uncovers the problem of how to differentiate Australia from its British heritage without duplicating the motherland\u27s creation of rigid identities that suppress the potential for growth. A chapter on White\u27s work suggests one solution: refusing to turn any single view of Australia\u27s past into a national monument. Duncan\u27s texts are shown to advocate a familial metaphor of the colonial relationship, suggesting that political bonds, like family roles, must shift over time. Hodgins, finally, recommends looking at present relationships in order to break past ones.;Of the numerous similar methods used by Australians and Canadians to explain their relationship with Britain, imagery of an emotional bond is among the strongest. The colony is invariably depicted as requiring the process of loving and later missing the other in order to attain maturity. The tension between those who wish to replicate the parent culture and those who reject it also produces a need for communities which replace the mother, their power arising from the ability to perceive freshly through rejecting conformity
Determining the energetics of vicinal perovskite oxide surfaces
The energetics of vicinal SrTiO(001) and DyScO(110), prototypical
perovskite vicinal surfaces, has been studied using topographic atomic force
microscopy imaging. The kink formation and strain relaxation energies are
extracted from a statistical analysis of the step meandering. Both perovskite
surfaces have very similar kink formation energies and exhibit a similar
triangular step undulation. Our experiments suggest that the energetics of
perovskite oxide surfaces is mainly governed by the local oxygen coordination.Comment: 16 pages, 4 figure
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