327 research outputs found

    On a Dirichlet problem with (p,q)(p,q)-Laplacian and parametric concave-convex nonlinearity

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    A homogeneous Dirichlet problem with (p,q)(p,q)-Laplace differential operator and reaction given by a parametric pp-convex term plus a qq-concave one is investigated. A bifurcation-type result, describing changes in the set of positive solutions as the parameter λ>0\lambda>0 varies, is proven. Since for every admissible λ\lambda the problem has a smallest positive solution uˉλ\bar u_{\lambda}, both monotonicity and continuity of the map λuˉλ \lambda \mapsto \bar u_{\lambda} are studied.Comment: 12 pages, comments are welcom

    Public debt and economic growth: a review of contemporary literature

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    This article reviews the most important contributions to literature on “public debt - economic growth” relationship. Most relevant studies are empirical. Some of them are based on causality tests, albeit with no clear conclusion as to what the causes and what the effects are. We also indicate important gaps, which have not been considered and these are either periods of economic crises or “secular stagnation” phenomena. We suggest that policy makers and investors should reconsider not only the so-called 90% “threshold hypothesis” but also the causality itself, because there is no necessary theoretical consensus so far

    Constant sign and nodal solutions for a class of nonlinear Dirichlet problems

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    We consider a nonlinear Dirichlet problem with a Carathéodory reaction which has arbitrary growth from below. We show that the problem has at least three nontrivial smooth solutions, two of constant sign and the third nodal. In the semilinear case (i.e., p =2), with the reaction f(z, .)being C1and with subcritical growth, we show that there is a second nodal solution, for a total of four nontrivial smooth solutions. Finally,when the reaction has concave terms and is subcritical and for the nonlinear problem (i.e., 1 <p <∞) we show that again we can have the existence of three nontrivial smooth solutions, two of constant sign and a third nodal

    Towards an educational data literacy framework: enhancing the profiles of instructional designers and e-tutors of online and blended courses with new competences

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    In the era of digitalization of learning and teaching processes, Educational Data Literacy (EDL) is highly valued and is becoming essential. EDL is conceptualized as the ability to collect, manage, analyse, comprehend, interpret, and act upon educational data in an ethical, meaningful, and critical manner. The professionals in the field of digitally supported education, i.e., Instructional Designers (IDs) and e-Tutors (eTUTs) of online and blended courses, need to be ready to inform their decisions with educational data, and face the upcoming data-related challenges; they need to update and enhance their profiles with relevant competences. This paper proposes a framework for EDL competence profiles of IDs/eTUTs and evaluates the proposal with the participation of worldwide professionals (N = 210) with experience in digitally supported education. The evaluation aims at validating the proposal and assesses (a) the current EDL-readiness of IDs/eTUTs; and (b) the extent to which the framework captures and describes the essential EDL competences. The findings indicate that professionals are not EDL-competent yet, but the proposed dimensions and related competences are offering a solid approach to support EDL development

    Translational Block in Stroke: A Constructive and Out-of-the-Box Reappraisal

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    Why can we still not translate preclinical research to clinical treatments for acute strokes? Despite > 1000 successful preclinical studies, drugs, and concepts for acute stroke, only two have reached clinical translation. This is the translational block. Yet, we continue to routinely model strokes using almost the same concepts we have used for over 30 years. Methodological improvements and criteria from the last decade have shed some light but have not solved the problem. In this conceptual analysis, we review the current status and reappraise it by thinking “out-of-the-box” and over the edges. As such, we query why other scientific fields have also faced the same translational failures, to find common denominators. In parallel, we query how migraine, multiple sclerosis, and hypothermia in hypoxic encephalopathy have achieved significant translation successes. Should we view ischemic stroke as a “chronic, relapsing, vascular” disease, then secondary prevention strategies are also a successful translation. Finally, based on the lessons learned, we propose how stroke should be modeled, and how preclinical and clinical scientists, editors, grant reviewers, and industry should reconsider their routine way of conducting research. Translational success for stroke treatments may eventually require a bold change with solutions that are outside of the box
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