186,402 research outputs found
Geometric aspects of p-capacitary potentials
No full textWe provide monotonicity formulas for solutions to the p-Laplace equation defined in the exterior of a convex domain. A number of analytic and geometric consequences are derived, including the classical Minkowski inequality as well as new characterizations of rotationally symmetric solutions and domains. The proofs rely on the conformal splitting technique introduced by the second author in collaboration with V. Agostiniani
Scambio di modelli o di oggetti. Analisi archeometriche su ceramiche Serra d'Alto da contesti VBQ in Emilia occidentale
No full textMODEL OF PRODUCTION OF FINISHED POTS EXCHANGE. ARCHAEOMETRIC ANALYSIS OF SERRA D'ALTO POTS FROM SMP SETTLEMENTS IN WESTERN EMILIA. This study aims to explore the issue of circulation in Northern Italy of finished pots of Mid-Late Neolithic ‘Serra d’Alto’ ware, rather than of production model of this ware. The 32 potsherds were analyzed by means of petrographic analysis and they can be divided into 13 different fabrics for their composition and grain-size distribution. Fine ware was produced using local Eocene and Oligocene clays, while almost all the coarse ware was tempered with spatic calcite clasts. The differences observed in thin section point to a common paste processing for fine and coarse wares which must have occurred in different places with different raw materials. The data suggests a polycentric production based on a common technological background. The hypothesis of circulation of finished ceramic pots was not validated while a widespread technological model probably occurred in different areas of Northern and Southern Italy.SCAMBIO DI MODELLI O DI OGGETTI. ANALISI ARCHEOMETRICHE SU CERAMICHE SERRA D'ALTO DA CONTESTI VBQ IN EMILIA OCCIDENTALE. Nella formazione e nello sviluppo delle culture del Neolitico pieno dell’area padana s’intrecciano radici locali, condivisioni di tratti comuni a vasti ambiti culturali ed elementi francamente esogeni, in particolare dal mondo Serra d’Alto, spesso rielaborati e fatti propri. Intento del contributo è verificare sulle produzioni in ceramica figulina rinvenute in contesti emiliani eventuali specifiche affinità di ordine tecnologico con le produzioni Serra d’Alto dell’Italia meridionale, già oggetto di sistematiche indagini archeometriche
Minimising hulls, p-capacity and isoperimetric inequality on complete Riemannian manifolds
No full textThe notion of strictly outward minimising hull is investigated for open sets of finite perimeter sitting inside a complete noncompact Riemannian manifold. Under natural geometric assumptions on the ambient manifold, the strictly outward minimising hull Ω⁎ of a set Ω is characterised as a maximal volume solution of the least area problem with obstacle, where the obstacle is the set itself. In the case where Ω has C1,α-boundary, the area of ∂Ω⁎ is recovered as the limit of the p-capacities of Ω, as p→1+. Finally, building on the existence of strictly outward minimising exhaustions, a sharp isoperimetric inequality is deduced on complete noncompact manifolds with nonnegative Ricci curvature, provided 3≤n≤7
High-order Discontinuous Galerkin methods for the elastodynamics equation on polygonal and polyhedral meshes
No full textWe propose and analyze a high-order Discontinuous Galerkin Finite Element Method for the approximate solution of wave propagation problems modeled by the elastodynamics equations on computational meshes made by polygonal and polyhedral elements. We analyze the well posedness of the resulting formulation, prove hp-version error a-priori estimates, and present a dispersion analysis, showing that polygonal meshes behave as classical simplicial/quadrilateral grids in terms of dispersion properties. The theoretical estimates are confirmed through various two-dimensional numerical verifications
A discontinuous Galerkin time integration scheme for second order differential equations with applications to seismic wave propagation problems
No full textIn this work, we present a high-order Discontinuous Galerkin time integration scheme for second-order (in time) differential systems that typically arise from the space discretization of the elastodynamics equation. By rewriting the original equation as a system of first-order differential equations we introduce the method and show that the resulting discrete formulation is well-posed, stable, and retains a super-optimal rate of convergence with respect to the discretization parameters, namely the time step and the polynomial approximation degree. A set of two-and three-dimensional numerical experiments confirm the theoretical bounds. Finally, the method is applied to real geophysical simulations
The asymptotic behaviour of p-capacitary potentials in asymptotically conical manifolds
No full textWe study the asymptotic behaviour of the p-capacitary potential and of the weak inverse mean curvature flow of a bounded set along the ends of an asymptotically conical Riemannian manifolds with asymptotically nonnegative Ricci curvature
A high-order discontinuous Galerkin approach to the elasto-acoustic problem
No full textWe address the spatial discretization of an evolution problem arising from the coupling of elastic and acoustic wave propagation phenomena by employing a discontinuous Galerkin scheme on polygonal and polyhedral meshes. The coupled nature of the problem is ascribed to suitable transmission conditions imposed at the interface between the solid (elastic) and fluid (acoustic) domains. We state and prove a well-posedness result for the strong formulation of the problem, present a stability analysis for the semi-discrete formulation, and finally prove an a priori hp-version error estimate for the resulting formulation in a suitable (mesh-dependent) energy norm. We also discuss the time integration scheme employed to obtain the fully discrete system. The convergence results are validated by numerical experiments carried out in a two-dimensional setting
Simulation of three-dimensional elastoacoustic wave propagation based on a Discontinuous Galerkin spectral element method
No full textIn this article, we present a numerical discretization of the coupled elastoacoustic wave propagation problem based on a discontinuous Galerkin spectral element approach in a three-dimensional setting. The unknowns of the coupled problem are the displacement field and the velocity potential, in the elastic and the acoustic domains, respectively, thereby resulting in a symmetric formulation. After stating the main theoretical results, we assess the performance of the method by convergence tests carried out on both matching and nonmatching grids, and we simulate realistic scenarios where elastoacoustic coupling occurs. In particular, we consider the case of Scholte waves, the scattering of elastic waves by an underground acoustic cavity, and a problem of marine seismic exploration. Numerical simulations are carried out by means of the code SPEED, available at http://speed.mox.polimi.it
Treatment of hypertension in the elderly: target the lowest well-tolerated blood pressure
No full textIntroductionAntihypertensive treatment provides substantial benefits in older people. However, many challenges remain, including the ideal blood pressure (BP) target to be achieved. Because the elderly population is particularly vulnerable to adverse events, BP control should be carefully managed. Some studies have evaluated the cardiovascular effects of different BP targets in older patients, with mixed results and uncertainty about the most appropriate BP target. However, pooled analyses suggest that intensive BP lowering provides greater cardiovascular protection than less intensive strategies in elderly hypertensive patients.Areas coveredUnderstanding the balance between the risks and benefits of intensive BP targets and individualizing treatment is essential to ensure that older patients receive appropriate treatment to reduce the risk of cardiovascular complications. We reviewed data from clinical trials which investigated the protective effects of BP lowering drugs in elderly hypertensive patients aged >= 65 years.Expert opinionEvidence suggests that age does not preclude an aggressive strategy for treating hypertension in elderly patients. Being 'tolerant' with one hand and 'intensive' with the other should become a universal standard in the management of elderly hypertensive patients. The lowest well-tolerated BP could be a simple and universally applicable BP target in the management of hypertensive patients, including the elderly
Moral Values and Codes of Ethics of the World’s Ten Biggest Food and Beverage Companies
No full textThe aims of this paper is to analyse the codes of ethics of the most important companies operating in the food sector, in order to appreciate the attribute, the contents and the language of the code and then try to understand the aptitude of the code for assuring that moral values move the companies’ actions and strategies. The code of ethics is a basic tool of corporate governance, through which rules of corporate behaviour are defined and communicated internally and externally from the company. Many international researches about codes of ethics – summarised in the theoretical framework – are a starting point for this paper. In particular, our paper is focused on the language used in the codes in order to outline the most important issue regulated in these tools: principle and value, normative issue, and so on. The research considers the codes of the ten big companies that dominate the food market (the “Big Ten”): Associated British Foods (ABF), Coca-Cola, Danone, General Mills, Kellogg’s, Mars, Mondelēz International (ex Kraft Foods), Nestlé, PepsiCo and Unilever. The analysis examines the vocabulary of each code in order to identify the “bag of words” by extrapolating the special words and the ethical and moral values that characterize the codes. We want to identify the most important information with regard to the issues regulated in the code and we expect to evaluate to what extent the language used, which contains the ethical and moral values of the sector, can represent a status both at the individual company level both at the sector level. Specifically, we arise the following research questions: RQ1: Are there differences among the contents and the languages used in the codes of ethics of the “Big Ten” analysed? RQ2: What are the most important matters regulated in the codes? and the most important values considered? RQ3: Can be matters and values considered at company level or at the sector level? It is possible to define a model for contents and language of codes of ethics for the food sector
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