Near-best univariate spline discrete quasi-interpolants on non-uniform partitions

International audienceUnivariate spline discrete quasi-interpolants (abbr. dQIs) are approximation operators using B-spline expansions with coefficients which are linear combinations of discrete values of the function to be approximated. When working with nonuniform partitions, the main challenge is to find dQIs which have both good approximation orders and bounded uniform norms independent of the given partition. Near-best dQIs are obtained by minimizing an upper bound of the infinite norm of dQIs depending on a certain number of free parameters, thus reducing this norm. This paper is devoted to the study of some families of near-best dQIs of approximation order 2

Near-best quasi-interpolants associated with H-splines on a three-directional mesh.

International audienceSpline quasi-interpolants with best approximation orders and small norms are useful in several applications. In this paper, we construct the so-called near-best discrete and integral quasi-interpolants based on H-splines, i.e., B-splines with regular hexagonal supports on the uniform three-directional mesh of the plane. These quasi-interpolants are obtained so as to be exact on some space of polynomials, and minimize an upper bound of their infinite norms depending on a finite number of free parameters. We show that this problem has always a solution, but it is not unique in general. Concrete examples of these types of quasi-interpolants are given in the two last sections

Near-best bivariate spline quasi-interpolants on a four-directional mesh of the plane

Spline quasi-interpolants (QIs) are practical and effective approximation operators. In this paper, we construct QIs with optimal approximation orders and small infinity norms called near-best discrete and integral quasi-interpolants which are based on $\Omega$-~splines, i.e. B-splines with regular lozenge supports on the uniform four directional mesh of the plane. These quasi-interpolants are obtained so as to be exact on some space of polynomials and to minimize an upper bound of their infinity norms which depend on a finite number of free parameters. We show that this problem has always a solution, which is not unique in general. Concrete examples of these types of quasi-interpolants are given in the last section

Near minimally normed spline quasi-interpolants on uniform partitions

International audienceSpline quasi-interpolants are local approximating operators for functions or discrete data. We consider the construction of discrete and integral spline quasi-interpolants on uniform partitions of the real line having small infinite norms. We call them near minimally normed quasi-interpolants: they are exact on polynomial spaces and minimize a simple upper bound of their infinite norms. We give precise results for cubic and quintic quasi-interpolants. Also the quasi-interpolation error is considered, as well as the advantage that these quasi-interpolants present when approximating functions with isolated discontinuities

Produção escrita de narrativas: influência de condições de solicitação

A habilidade de produzir narrativas não emerge repentinamente, apresenta um desenvolvimento gradual, cujo percurso é influenciado por vários fatores, dentre os quais, destacam-se: idade; escolaridade; experiências prévias com textos; tipo de solicitação, ou seja, produção livre, a partir de gravuras, de ilustrações de livros infantis, relatos de fatos ocorridos, reprodução de histórias contadas, entre outros. Há indícios de que, no início da escolarização, as narrativas apresentam-se melhor estruturadas quando a condição de solicitação oferece apoio visual, sobretudo quando este apresenta algum tipo de conflito. Nesta pesquisa, investigamos: 7(1) o desempenho na produção de narrativas de alunos do 3º e 5º anos do ensino fundamental, sob diferentes condições de produção: com apoio visual e verbal e com e sem sugestão de conflito e (2) os efeitos da escolaridade no desempenho em produção de narrativas. Os alunos foram solicitados a produzirem histórias (um tipo particular de narrativa) em seis diferentes condições. Os resultados mostram que, embora o apoio visual seja relevante na qualidade narrativa de histórias, ele não é fator determinante. A presença de sugestão de conflito parece ser também um elemento favorecedor. Nossos dados apontam também efeito positivo da escolaridade na qualidade narrativa dos textos produzidos pelos alunos investigados. Discute-se a importância de práticas pedagógicas que promovam a aprendizagem de conhecimentos explícitos relativos à estrutura dos diferentes tipos de texto, de modo a propiciar maior competência dos alunos na produção textual

Caracterización mecánica de mezclas de caucho natural y residuos de celulosa originados en la industria automotriz con enfoque en el sector del calzado

Context: This publication shows a potential use for waste from the automotive industry, namely waste originating in the manufacturing process of gaskets and seals for motorcycles, which currently do not have a final use. In addition, due to their high-performance rubber surface layer, they imply an extensive degradation process, which constitutes a harmful factor for the environment and contributes to global warming. Method: First, the crushing of the residues was carried out, then their sieving and selection via granulometry, and finally a mixture with the natural rubber through chewing in open cylinders in order to obtain the master, which was vulcanized in a shoe sole mold. The final product was mechanically characterized via the techniques, tension-elongation, wear, hardness, bending, and tearing. Results: The obtained mixture opens a window to the design of products using residues from seals and gaskets for motors. It will be possible to design other proposals for functionalized rubbers, oriented towards the development of ecological footwear applications. Conclusions: The mixture of cellulose waste from the motor seal sector and natural rubber shows promise for the reduction of the negative impact caused by these wastes and proposes a circular economy –in this case, with the development of raw material in the footwear sector.Contexto: Esta publicación muestra un potencial uso para los residuos provenientes de la industria automotriz, en este caso residuos originados en el proceso de fabricación de empaques y sellos para motocicletas, que en la actualidad no tienen un uso final. Además, debido a la capa superficial de caucho de altas prestaciones, presentan un proceso de degradación extenso, lo cual constituye un factor perjudicial para el medio ambiente y contribuye al calentamiento global. Método: Primero se realizó la trituración de los residuos, posteriormente su tamizado y selección por granulometría, y por último se realizó una mezcla con el caucho natural a través del masticado en cilindros abiertos para obtener el máster, que fue vulcanizado en un molde de suela para zapatos. El producto final fue caracterizado mecánicamente con las técnicas tensión-elongación, desgaste, dureza, flexión y rasgadura. Resultados: La mezcla obtenida abre una ventana hacia el diseño de productos utilizando residuos de sellos y empaques para motor. Será posible diseñar otras propuestas para cauchos funcionalizados, orientados al desarrollo de aplicaciones de calzado ecológico. Conclusiones: La mezcla de residuos de celulosa provenientes del sector de sellos para motor con caucho natural proyecta la reducción del impacto negativo generado por estos residuos y propone una economía circular, en este caso con el desarrollo de materia prima para el sector del calzado

Documentación Gráfica del Patrimonio: Un paso adelante

La documentación gráfica de patrimonio tiene como finalidad primordial el conocimiento integral del objeto arquitectónico o arqueológico. El primer nivel de salvaguardia es el conocimiento y conocer quiere decir documentar. La DOCUMENTACIÓN constituye el soporte indispensable para la tutela del patrimonio cultural, constituye además el requisito previo para toda intervención en el Patrimonio. Nuestro trabajo no debe limitarse a un conjunto de operaciones de medida y su posterior representación. Nuestros gráficos deben transmitir o reflejar el análisis crítico que nos permita comprender el edificio o bien en su configuración completa, referida a su contexto urbano o territorial. Debemos observar las características dimensionales y métricas, estructurales y constructivas, formales y funcionales, e incluso históricas que motivaron las decisiones adoptadas Los grandes avances en software y hardware constituyen una ayuda indispensable para la generación de modelos tridimensionales del patrimonio que nos permitan no solo conocer el elemento con mayor profundidad y precisión en mucho menor tiempo sino una herramienta de comunicación y difusión del nuestro patrimoni

The dipole moment of alcohols in the liquid phase and in solution

Understanding polarization effects in condensed phases, like liquids and solutions, requires computational methods that can accurately predict dipole moments and energy of polarized molecules. In this paper, we report an improvement and extension of our recently developed Self-Consistent Electrostatic Embedding (SCEE) method, and apply it to determine the dipole moment of pure liquid alcohols, as well as of methanol dissolved in a variety of solvents (namely, other alcohols, water and hexadecane). We observe that the dipole moments of pure liquid alcohols are enhanced by ∼0.9 D over their gas phase values, which is similar to the dipole enhancement previously observed for water, and much higher than what is predicted by dielectric continuum models. Our results demonstrate the importance of accounting for local solvation effects, namely the formation of hydrogen bonds, when calculating the extent of liquid phase polarization. In fact, we argue that the dipole enhancement upon solvation can be explained as a superposition of two effects: bulk screening described by the solvent dielectric constant and local solvation that requires a discrete molecular-level description of the system. SCEE is able to account for both effects simultaneously, and is thus a powerful tool to estimate polarization effects in liquids and solutions

Lower incisor position in different malocclusions and facial patter

Introduction: The position of lower incisor has been of considerable concern when planning an orthodontic treatment, having been recognized as one of diagnostic keys, Very important in the development of malocclusion and facial pattern. Objectives: In this study we claim to determine the importance of the position and inclination of lower incisor in the different malocclusions and facial patterns, and to base which of the cephalometric measurement parameters are the mostreliable. Material and Methods: Ninety lateral radiographies were taken, and they were classified by skeletal malocclusion and facial pattern.These teleradiographies have been performed cephalometric analysis, which includelower incisor position belong the following analysis: Ricketts, Riolo, Tweed, McHorris, Jarabak-MSE and Holdaway. Study Design: Cross-sectional study where we perform statistical analysis Anova test, Pearson correlations and Bonferroni analysis. Results: The analyzed measurements present a statistically significant differentiation in lower incisor inclination respect to the anterior cranial base, McHorris angle, angulation of lower incisor respect to occlusal plane and mandibular plane. Conclusions: There are statistically significant differentiation in lower incisor position and inclination respect the malocclusion and individual facial pattern