26,737 research outputs found

    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

    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

    Lower cerebrospinal fluid/plasma fibroblast growth factor 21 (FGF21) ratios and placental FGF21 production in gestational diabetes

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    Objectives: Circulating Fibroblast Growth Factor 21 (FGF21) levels are increased in insulin resistant states such as obesity, type 2 diabetes mellitus and gestational diabetes mellitus (GDM). In addition, GDM is associated with serious maternal and fetal complications. We sought to study human cerebrospinal fluid (CSF) and corresponding circulating FGF21 levels in women with gestational diabetes mellitus (GDM) and in age and BMI matched control subjects. We also assessed FGF21 secretion from GDM and control human placental explants. Design: CSF and corresponding plasma FGF21 levels of 24 women were measured by ELISA [12 GDM (age: 26–47 years, BMI: 24.3–36.3 kg/m2) and 12 controls (age: 22–40 years, BMI: 30.1–37.0 kg/m2)]. FGF21 levels in conditioned media were secretion from GDM and control human placental explants were also measured by ELISA. Results: Glucose, HOMA-IR and circulating NEFA levels were significantly higher in women with GDM compared to control subjects. Plasma FGF21 levels were significantly higher in women with GDM compared to control subjects [234.3 (150.2–352.7) vs. 115.5 (60.5–188.7) pg/ml; P<0.05]. However, there was no significant difference in CSF FGF21 levels in women with GDM compared to control subjects. Interestingly, CSF/Plasma FGF21 ratio was significantly lower in women with GDM compared to control subjects [0.4 (0.3–0.6) vs. 0.8 (0.5–1.6); P<0.05]. FGF21 secretion into conditioned media was significantly lower in human placental explants from women with GDM compared to control subjects (P<0.05). Conclusions: The central actions of FGF21 in GDM subjects maybe pivotal in the pathogenesis of insulin resistance in GDM subjects. The significance of FGF21 produced by the placenta remains uncharted and maybe crucial in our understanding of the patho-physiology of GDM and its associated maternal and fetal complications. Future research should seek to elucidate these points

    Journeying from “I” to “we”: assembling hybrid caring collectives of geography doctoral scholars

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    This is an Accepted Manuscript of an article published by Taylor & Francis in "Journal of Geography in Higher Education" on 15 June 2017, available at: https://www.tandfonline.com/doi/full/10.1080/03098265.2017.133529

    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

    Gap modification of atomically thin boron nitride by phonon mediated interactions

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    A theory is presented for the modification of bandgaps in atomically thin boron nitride (BN) by attractive interactions mediated through phonons in a polarizable substrate, or in the BN plane. Gap equations are solved, and gap enhancements are found to range up to 70% for dimensionless electron-phonon coupling \lambda=1, indicating that a proportion of the measured BN bandgap may have a phonon origin

    Determinants for Successful Agile Collaboration between UX Designers and Software Developers in a Complex Organisation

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    Agile and User-centered design processes have been reported to frequently putting contradictory demands on people working within these methodological frameworks. The current research addresses this point by focussing on the crucial relationship between software developer and designer. An online survey, a contextual inquiry, and a diary study were employed with 107 developers and designers in a large media organization to determine the factors for success in agile development cycles. The results from the survey show that while developers and designers have similar levels of satisfaction with agile processes, there are differences in the factors predicting those ratings. Developers are happier with the wider teamwork but want more access to and close collaboration with designers, while the latters’ concern was the quality of the wider teamwork. Additional contextual inquiries and a diary study with pairs of designers and developers reflected the survey findings that close cooperation (and proximity) was essential for improving communication, reducing inefficiencies, and avoiding suboptimal products being released. However, organizational processes, the setup of the work environment, and managerial traditions meant that this close collaboration and localized decision-making was found difficult to maintain. Results from the survey, the contextual inquiry, and the diary study found six factors for success from collaborations emerged

    High-energy scale revival and giant kink in the dispersion of a cuprate superconductor

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    In the present photoemission study of a cuprate superconductor Bi1.74Pb0.38Sr1.88CuO6+delta, we discovered a large scale dispersion of the lowest band, which unexpectedly follows the band structure calculation very well. The incoherent nature of the spectra suggests that the hopping-dominated dispersion occurs possibly with the assistance of local spin correlations. A giant kink in the dispersion is observed, and the complete self-energy containing all interaction information is extracted for a doped cuprate in the low energy region. These results recovered significant missing pieces in our current understanding of the electronic structure of cuprates.Comment: 4 pages, 3 figures, submitted to Phys. Rev. Lett. on May 21, 200

    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

    Leveraging dynamic export capabilities for competitive advantage and performance consequences: Evidence from China

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    As the business arena becomes more global and therefore dynamic, organizations must balance their capabilities with the demands and the conditions of the international marketplace. This leads firms to trade off the development of more capabilities with the identification of core capabilities which can best improve export competitiveness and performance. Based on the Dynamic Capabilities Approach (DCA), we develop a model of four export capabilities, namely adaptability, innovativeness, unpredictability, and task-flexibility, aimed at achieving competitive advantage in foreign markets and enhance export performance. Based on a survey of 213 Chinese exporting organizations, we find out that innovativeness, unpredictability and task-flexibility are positively related to competitive advantage, while adaptability is negatively related to it. Moreover, we uncovered that in the cases of adaptability, innovativeness and task-flexibility their impact on competitive advantage diminishes under higher levels of competitive intensity, however, for unpredictability this impact becomes negative. We also confirm the necessity of addressing competitive advantage separately from firms’ performance
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