3,316 research outputs found

    System Design, User Cost and Electronic Usage of Journals

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    Dramatic increases in the capabilities and decreases in the costs of computers and communication networks have fomented revolutionary thoughts in the scholarly publishing community. In one dimension, traditional pricing schemes and product packages are being modified or replaced. We designed and undertook a large-scale field experiment in pricing and bundling for electronic access to scholarly journals: PEAK. We provided Internet-based delivery of content from 1200 Elsevier Science journals to users at multiple campuses and commercial facilities. Our primary research objective was to generate rich empirical evidence on user behavior when faced with various bundling schemes and price structures. In this article we explain the different types and levels of cost that users faced when accessing individual articles, and report on the effect of these costs on usage. We found that both monetary and non-monetary user costs have a significant impact on the demand for electronic access. We also estimate how taking user costs into account would change the optimal (least cost) bundle of access options that an institution should purchase.

    Pricing and Bundling Electronic Information Goods: Field Evidence

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    Dramatic increases in the capabilities and decreases in the costs of computers and communication networks have fomented revolutionary thoughts in the scholarly publishing community. In one dimension, traditional pricing schemes and product packages are being modified or replaced. We designed and undertook a large-scale field experiment in pricing and bundling for electronic access to scholarly journals: PEAK. We provided Internet-based delivery of content from 1200 Elsevier Science journals to users at multiple campuses and commercial facilities. Our primary research objective was to generate rich empirical evidence on user behavior when faced with various bundling schemes and price structures. In this article we report initial results. We found that although there is a steep initial learning curve, decision-makers rapidly comprehended our innovative pricing schemes. We also found that our novel and flexible "generalized subscription" was successful at balancing paid usage with easy access to a larger body of content than was previously available to participating institutions. Finally, we found that both monetary and non-monetary user costs have a significant impact on the demand for electronic access.

    Improving Learning Performance by Applying Economic Knowledge

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    Digital information economies require information goods producers to learn how to position themselves within a potentially vast product space. Further, the topography of this space is often nonstationary, due to the interactive dynamics of multiple producers changing their position as they try to learn the distribution of consumer preferences and other features of the problem's economic structure. This presents a producer or its agent with a difficult learning problem: how to locate profitable niches in a very large space. In this paper, we present a model of an information goods duopoly and show that, under complete information, producers would prefer not to compete, instead acting as local monopolists and targeting separate niches in the consumer population. However, when producers have no information about the problem they are solving, it can be quite difficult for them to converge on this solution. We show how a modest amount of economic knowledge about the problem can make it much easier, either by reducing the search space, starting in a useful area of the space, or introducing a gradient. These experiments support the hypothesis that a producer using some knowledge of a problem's (economic) structure can outperform a producer that is performing a naive, knowledge-free form of learning.

    Host-Imposed Copper Poisoning Impacts Fungal Micronutrient Acquisition during Systemic Candida albicans Infections

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    This work was supported by the European Research Council (http://erc.europa.eu/: STRIFE Advanced Grant ERC-2009-AdG-249793). A.J.P.B. was also supported by the UK Biotechnology and Biological Research Council (www.bbsrc.ac.uk: Research Grants BB/F00513X/1, BB/K017365/1), the UK Medical Research Council (www.mrc.ac.uk: Programme Grant MR/M026663/1; Centre Grant MR/ N006364/1), and the Wellcome Trust (www.wellcome.ac.uk: Strategic Award 097377)Peer reviewedPublisher PD

    Influence of Vertical Ground Motions on the Seismic Fragility Modeling of a Bridge-Soil-Foundation System

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    This paper explores the effects of vertical ground motions (VGMs) on the component fragility of a coupled bridged-soil-foundation (CBSF) system with liquefaction potential, and highlights the unique considerations on the demand and capacity model required for fragility analysis under VGMs. Optimal intensity measures (IMs) that account for VGMs are identified. Moreover, fragility curves that consider capacity change with fluctuating axial force are derived. Results show that the presence of VGMs has a minor effect on the failure probabilities of piles and expansion bearings, while it has a great influence on fixed bearings. Whether VGMs have an impact on column fragilities depends on the design axial load ratio. Finally, more accurate fragility surfaces are derived, which are compared with results of conventional fragility curves. This study highlights the important role that VGMs play in the selection of optimal IMs, and the capacity and fragility representation of certain components of CBSF systems

    Hormone replacement therapy after surgery for stage 1 or 2 cutaneous melanoma

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    A total of 206 women were followed for a minimum of 5 years after primary melanoma surgery to establish if hormone replacement therapy (HRT) adversely affected prognosis. In all, 123 had no HRT and 22 have died of melanoma; 83 had HRT for varying periods and one has died of melanoma. After controlling for known prognostic factors, we conclude that HRT after melanoma does not adversely affect prognosis

    Measures of oxidative state are primarily driven by extrinsic factors in a long-distance migrant

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    This is the author accepted manuscript. The final version is available from the Royal Society via the DOI in this recordData accessibility: Data are available from the Dryad Digital Repository: https://doi.org/10.5061/dryad.j4k3t6f/1 [20].Oxidative stress is a likely consequence of hard physical exertion and thus a potential mediator of life-history trade-offs in migratory animals. However, little is known about the relative importance of intrinsic and extrinsic stressors on the oxidative state of individuals in wild populations. We quantified the relationships between air temperature, sex, body condition and three markers of oxidative state (malondialdehyde, superoxide dismutase and total antioxidant capacity) across hundreds of individuals of a long-distance migrant (the brent goose Branta bernicla hrota) during wintering and spring staging. We found that air temperature and migratory stage were the strongest predictors of oxidative state. This emphasizes the importance of extrinsic factors in regulating the oxidative state of migrating birds, with differential effects across the migration. The significance of abiotic effects demonstrates an additional mechanism by which changing climates may affect migratory costs.European Commissio

    Superposition of macroscopic numbers of atoms and molecules

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    We theoretically examine photoassociation of a non-ideal Bose-Einstein condensate, focusing on evidence for a macroscopic superposition of atoms and molecules. This problem raises an interest because, rather than two states of a given object, an atom-molecule system is a seemingly impossible macroscopic superposition of different objects. Nevertheless, photoassociation enables coherent intraparticle conversion, and we thereby propose a viable scheme for creating a superposition of a macroscopic number of atoms with a macroscopic number of molecules.Comment: 4 pages, 2 figs, to appear in Phys. Rev. Let

    A 2dF spectroscopic study of globular clusters in NGC 5128: Probing the formation history of the nearest giant Elliptical

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    We have performed a spectroscopic study of globular clusters (GCs) in the giant elliptical NGC 5128 using the 2dF facility at the Anglo-Australian telescope. We obtained integrated optical spectra for a total of 254 GCs, 79 of which are newly confirmed on the basis of their radial velocities and spectra. In addition, we obtained an integrated spectrum of the galaxy starlight along the southern major axis. We derive an empirical metallicity distribution function (MDF) for 207 GCs (~14 of the estimated total GC system) based upon Milky Way GCs. This MDF is multimodal at high statistical significance with peaks at [Z/H]~-1.3 and -0.5. A comparison between the GC MDF and that of the stellar halo at 20 kpc (~4 Reff) reveals close coincidence at the metal-rich ends of the distributions. However, an inner 8 kpc stellar MDF shows a clear excess of metal-rich stars when compared to the GCs. We compare a higher S/N subsample (147 GCs) with two stellar population models which include non-solar abundance ratio corrections. The vast majority of our sample (~90%) appears old, with ages similar to the Milky Way GC system. There is evidence for a population of intermediate-age (~4-8 Gy) GCs (<15% of the sample) which are on average more metal-rich than the old GCs. We also identify at least one younger cluster (~1-2 Gy) in the central regions of the galaxy. Our observations are consistent with a picture where NGC 5128 has undergone at least two mergers and/or interactions involving star formation and limited GC formation since z=1, however the effect of non-canonical hot stellar populations on the integrated spectra of GCs remains an outstanding uncertainty in our GC age estimates.Comment: 17 figures, some long table

    User cost, usage and library purchasing of electronically-accessed journals

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    http://deepblue.lib.umich.edu/bitstream/2027.42/63447/3/gazzale-jmm-user-cost-peak-book.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/63447/2/gazzale-jmm-peak-usercost_files.ziphttp://deepblue.lib.umich.edu/bitstream/2027.42/63447/1/gazzale-jmm-peak-usercost.htm
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