21,633 research outputs found

    An agile information-architecture-driven approach for the development of user-centered interactive software

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    This is the author's version of the work. It is posted here for your personal use. Not for redistribution. The definitive Version of Record was published in Interacción '15: Proceedings of the XVI International Conference on Human Computer Interaction, http://dx.doi.org/10.1145/2829875.2829919.For the most part, Information Architecture processes include sets of activities and techniques to be carried out by the development team to create interactive applications effectively, involving usability concerns at every development step. In fact, plenty of process models have already been proposed to bridge the gap between User-Centered Development and Information Architecture, empowering the development team to build usable applications successfully. However, the combination of User- Centered Development and Information Architecture paradigms sometimes results in cumbersome process models containing lots of phases and activities to be considered, which increases the cycle time to have partial and validated software increments readily. As less effort has been devoted to speed up the usable Information Architecture development, the aim of this paper is to address such problem. To do so, we present Scrum-UIA, an agile and usable development process driven by the Information Architecture. This process is intended to develop web applications by splitting up responsibilities and tasks, and decreasing the time to perform technical activities, in order to readily obtain usable software increments.This work has been supported by the funding projects «eMadrid», granted by the Madrid Research Council (project code S2013/ICE-2715) and «Flexor», granted by the Spanish Government (project code TIN2014-52129-R)

    Reconstructing Colonization Dynamics of the Human Parasite Schistosoma mansoni following Anthropogenic Environmental Changes in Northwest Senegal

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    © 2015 Van den Broeck et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. The attached file is the published version of the article

    A Spatio-Temporal Model Reveals Self-Limiting FcɛRI Cross-Linking by Multivalent Antigens

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    Aggregation of cell surface receptor proteins by multivalent antigens is an essential early step for immune cell signalling. A number of experimental and modelling studies in the past have investigated multivalent ligand-mediated aggregation of IgE receptors (FcɛRI) in the plasma membrane of mast cells. However, understanding of the mechanisms of FcɛRI aggregation remains incomplete. Experimental reports indicate that FcɛRI forms relatively small and finite-sized clusters when stimulated by a multivalent ligand. By contrast, modelling studies have shown that receptor cross-linking by a trivalent ligand may lead to the formation of large receptor superaggregates that may potentially give rise to hyperactive cellular responses. In this work, we have developed a Brownian dynamics-based spatio-temporal model to analyse FcɛRI aggregation by a trivalent antigen. Unlike the existing models, which implemented non-spatial simulation approaches, our model explicitly accounts for the coarse-grained site-specific features of the multivalent species (molecules and complexes). The model incorporates membrane diffusion, steric collisions and sub-nanometre-scale site-specific interaction of the time-evolving species of arbitrary structures. Using the model, we investigated temporal evolution of the species and their diffusivities. Consistent with a recent experimental report, our model predicted sharp decay in species mobility in the plasma membrane in response receptor cross-linking by a multivalent antigen. We show that, due to such decay in the species mobility, post-stimulation receptor aggregation may become self-limiting. Our analysis reveals a potential regulatory mechanism suppressing hyperactivation of immune cells in response to multivalent antigens

    The relationship between web enjoyment and student perceptions and learning using a web-based tutorial

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    Web enjoyment has been regarded as a component of system experience. However, there has been little targeted research considering the role of web enjoyment alone in student learning using web-based systems. To address this gap, this study aims to examine the influence of web enjoyment on learning performance and perceptions by controlling system experience as a variable in the study. 74 students participated in the study, using a web-based tutorial covering subject matter in the area of 'Computation and algorithms'. Their learning performance was assessed with a pre-test and a post-test and their learning perceptions were evaluated with a questionnaire. The results indicated that there are positive relationships between the levels of web enjoyment and perceived usefulness and non-linear navigation for users with similar, significant levels of system experience. The implications of these findings in relation to web-based learning are explored and ways in which the needs of students who report different levels of web enjoyment might be met are discussed

    Ground Improvement by Dynamic Compaction at a Tailings Disposal Facility

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    This paper presents two case histories of ground improvement by dynamic compaction (DC) at the Myra Falls mine in Vancouver Island, British Columbia, Canada. Dynamic compaction was employed to densify soils at two sites within the operating mine: a waste rock dump beneath a new processing plant to reduce settlements beneath the structure foundations (Site A); and coarse fluvial and colluvial soils at the toe of an existing tailings embankment to improve seismic resistance against liquefaction (Site B). At Site A, the variable plant loadings required variable compaction energy to achieve uniform foundation performance. At Site B, the foundation soils contained some fine grained soils that dictated a time-controlled sequential DC approach to allow excess pore pressures to dissipate between passes. Because of large uncertainties in the expected performance of DC at both sites, a fair and cost effective DC contract based on unit price per energy was adopted, instead of the traditional performance-based lump sum price contract. This paper describes the ground conditions at the two sites, DC methodologies employed, and ground improvement performance based on measurements of crater volumes and pre- and post-densification in-situ testing by Becker Penetration Tests

    Wigner-Seitz cells in neutron star crust with finite range interactions

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    The structure of Wigner-Seitz cells in the inner crust of neutron stars is investigated using a microcospic Hartree-Fock-BCS approach with finite range D1S and M3Y-P4 interactions. Large effects on the densities are found compared to previous predictions using Skyrme interactions. Pairing effects are found to be small, and they are attenuated by the use of finite range interactions in the mean field.Comment: 11 pages, 5 figure

    Mobile phone technologies in the management of ischemic heart disease, heart failure, and hypertension: systematic review and meta-analysis

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    Background: Cardiovascular disease (CVD) remains the leading cause of death worldwide. Mobile phones have become ubiquitous in most developed societies. Smartphone apps, telemonitoring, and clinician-driven SMS allow for novel opportunities and methods in managing chronic CVD, such as ischemic heart disease, heart failure, and hypertension, and in the conduct and support of cardiac rehabilitation. Objective: A systematic review was conducted using seven electronic databases, identifying all relevant randomized control trials (RCTs) featuring a mobile phone intervention (MPI) used in the management of chronic CVD. Outcomes assessed included mortality, hospitalizations, blood pressure (BP), and BMI. Methods: Electronic data searches were performed using seven databases from January 2000 to June 2019. Relevant articles were reviewed and analyzed. Meta-analysis was performed using standard techniques. The odds ratio (OR) was used as a summary statistic for dichotomous variables. A random effect model was used. Results: A total of 26 RCTs including 6713 patients were identified and are described in this review, and 12 RCTs were included in the meta-analysis. In patients with heart failure, MPIs were associated with a significantly lower rate of hospitalizations (244/792, 30.8% vs 287/803, 35.7%; n=1595; OR 0.77, 95% CI 0.62 to 0.97; P=.03; I2=0%). In patients with hypertension, patients exposed to MPIs had a significantly lower systolic BP (mean difference 4.3 mm Hg; 95% CI -7.8 to -0.78 mm Hg; n=2023; P=.02). Conclusions: The available data suggest that MPIs may have a role as a valuable adjunct in the management of chronic CVD

    Effects of Multi-Surface Modification on Curie temperature of ferroelectric films

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    Within the framework of mean field theory, we study the effects of multi-surface modification on Curie temperature of ferroelectric films using the transverse Ising model. The general nonlinear equations for Curie temperature of multi-surface ferroelectric films with arbitrary exchange constants and transverse fields are derived by the transfer matrix method. As an example, we consider a film consisting of top surface layers, bulk layers and bottom surface layers. Two types of surface modifications, modifications of a surface exchange constant and a surface transverse field are taken into account. The dependence of Curie temperature on the surface layer numbers, bulk layer numbers, surface exchange constants, surface transverse fields and bulk transverse fields is discussed.Comment: 11 pages, 5 figure
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