1,721,075 research outputs found
Asymptotic scaling symmetries for nonlinear PDEs
No full textIn some cases, solutions to nonlinear PDEs happen to be asymptotically (for large x and/or t) invariant under a group G which is not a symmetry of the equation. After recalling the geometrical meaning of symmetries of differential equations — and solution-preserving maps — we provide a precise definition of asymptotic symmetries of PDEs; we deal in particular, for ease of discussion and physical relevance, with scaling and translation symmetries of scalar equations. We apply the general discussion to a class of "Richardson-like" anomalous diffusion and reaction-diffusion equations, whose solution are known by numerical experiments to be asymptotically scale invariant; we obtain an analytical explanation of the numerically observed asymptotic scaling properties. We also apply our method to a different class of anomalous diffusion equations, relevant in optical lattices. The methods developed here can be applied to more general equations, as shown by their geometrical construction
A mathematical model of waxing and waning activity in isolated rat duedenum
No full textMonaco (germania
Female drinking, environment and biological markers
No full textThe rate of women involved in alcohol abuse is rapidly increasing and the age of first use tends dramatically to decrease. The health and social costs are high both for the adverse effects on physical and psychological woman health, and for the teratogenic effect of alcohol on fetal development. The review takes in account physiological aspects of alcohol effects according to age and gender differences. Interaction between alcohol habit and environment are discussed together with the risk of co-exposure to alcohol and pollutants. The role of biomarkers may be invaluable for clinical utility, prevention and early intervention above all to avoid prenatal, not reversible damages. The update of alcohol studies shows the greater severity of alcohol damage in female and the need of gender-targeted intervention
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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