1,356,883 research outputs found
Discrete approximation of a free discontinuity problem
No full textWe approximate by discrete GAMMA-convergence a functional proposed by Mumford-Shah for a variational approach to image segmentation. Such a functional is first relaxed with a sequence of nonconvex functionals, which in turn, are discretized by piecewise linear finite elements. Under a suitable relation between the relaxation parameter epsilon and the meshsize h, the convergence of the discrete functionals and the compactness of any sequence of discrete minimizers are proved. The proof relies on the techniques of GAMMA-convergence and on the properties of the Lagrange interpolation and Clement operator
Discrete approximation of a free discontinuity problem
No full textWe approximate by discrete GAMMA-convergence a functional proposed by Mumford-Shah for a variational approach to image segmentation. Such a functional is first relaxed with a sequence of nonconvex functionals, which in turn, are discretized by piecewise linear finite elements. Under a suitable relation between the relaxation parameter epsilon and the meshsize h, the convergence of the discrete functionals and the compactness of any sequence of discrete minimizers are proved. The proof relies on the techniques of GAMMA-convergence and on the properties of the Lagrange interpolation and Clement operators
Assessment of a topical product based on a mixture of polysulfated galactosaminoglycan in the topical treatment of postoperative blood extravasation (ecchymosis-hematoma) in phlebology
No full textBACKGROUND: The onset of bruising in surgery is a frequent event that can be a source of complications and delays in the patient’s healing process (pigmentations, fibrosis, etc.). Having the help of an effective topical product that speeds up the resorption of blood extravasation can be an advantage in phlebological surgery and surgery in general. METHODS: Twenty-three patients both male and female (age range: 30-72 years) were enrolled. Twenty-two of them completed the study, all underwent venous surgery of the lower extremities (invagination stripping of the internal or external saphenous and Muller’s ambulatory phlebectomy). The 22 patients were divided into 2 groups of 11 each and in a single blind study received topical daily therapy (every 12 hours) either in the form of a medication cream (active ingredient), or a placebo cream. All patients wore compression one-leg tights immediately after surgery, following measurement of the lower limb (Struva®35 mmHg, Medi Italia, Zola Predosa, Bologna, Italy). The 30-day observational study was carried out using a standard photographic survey procedure. RESULTS: The topical application of polysulfated galactosaminoglycan showed a significantly higher rate of resorption of blood extravasations than in patients in the single blind study receiving topical therapy with the placebo (Fisher’s Exact Test, dichotomous variable outcome, N.=22, with result P=0.0001<0.05). CONCLUSIONS: Topical therapy with a mixture of polysulfated galactosaminoglycans provides valid protection in the therapy of blood extravasations in phlebology and general surgery. (Cite this article as: izzo M, coscia v. assessment of a topical product based on a mixture of polysulfated galactosaminoglycan in the topical treatment of postoperative blood extravasation (ecchymosis-hematoma) in phlebology
On the mathematical theory of living systems, I: Complexity analysis and representation
No full textThis paper is the first one of a sequel devoted to the challenging goal of developing a mathematical theory for living systems. We consider systems constituted of a number of living entities, called active particles, which have the ability to express specific strategies
and interact with other entities. The author proposes a personal path, starting from the identification of a number of common features of living systems that can be viewed as sources of complexity, focusing specifically on the representation of systems based also on a strategy to reduce their complexity. The overall system is decomposed into
functional subsystems whose representation is delivered by a probability distribution over the microscopic state of the active particles belonging to such system. Looking ahead, this paper indicates some guidelines to derive mathematical structures, where interactions
involving active particles are nonlinearly additive
Nonlinear stability of a laminar flow past a two-dimensional grid
No full textSufficient conditions for the nonlinear stability of an exact solution to the Navier-Stokes equations (Kovasznay flow) are given by use of the energy method. These results markedly improve on earlier ones obtained by Lin and Tobak (Phy. Fluids 30, 3388 (1987))
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