986 resultados para TRANSFORMACIONES DE FOURIER


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New sufficient conditions for representation of a function via the absolutely convergent Fourier integral are obtained in the paper. In the main result, Theorem 1.1, this is controlled by the behavior near infinity of both the function and its derivative. This result is extended to any dimension d &= 2.

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L’objectiu principal d’aquest projecte és posar a punt el mètode d’anàlisi d’urea en llet crua de vaca mitjançant la tècnica d’Infraroig per Transformada de Fourier (Fourier Transform Infrared Spectroscopy, FTIR). S’haurà de portar a terme la validació del mètode per FTIR (seguint els criteris de la ISO 17025) mitjançant la comparació amb el mètode de referència utilitzat actualment al laboratori.

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"Vegeu el resum a l'inici del document del fitxer adjunt."

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La Integración de la Políticas Ambientales (IPA) consiste en la incorporación de los objetivos ambientales en todos los estadios de elaboración e implementación de las políticas no ambientales (o sectoriales), con un reconocimiento específico de dicho objetivo como principio director de la programación y la puesta en práctica. Se complementa con la previsión de las consecuencias ambientales mediante una evaluación de conjunto de la política con objeto de minimizar las contradicciones entre las políticas ambientales y no ambientales dando prioridad a las primeras. La naturaleza transversal de la IPA no se ajusta a la forma tradicional de gobernanza jerárquica basada en la autoridad del Estado, la diferenciación sectorial, y los instrumentos típicos de dirección y control. Por ello, no es extraño que la IPA se encuentre a menudo asociada a los llamados "nuevos modos de gobernanza". Esta tesis propone analizar empíricamente el estado de la cuestión en España con respecto a la Integración de la política ambiental , tanto a nivel estatal como autonómico (Cataluña, País Vasco), yendo más allá de los compromisos políticos a favor de un mayor grado de integración de los factores ambientales en las demás políticas. En particular, los ámbitos de investigación seleccionados para esta finalidad son el de las políticas de mitigación de las causas y los efectos del cambio climático, y las políticas de desarrollo sostenible. En términos de ‘variable independiente’ La hipótesis que se quiere comprobar es que la acción llevada a cabo por la Unión Europea ha generado profundos cambios en las estructuras de las instituciones mencionadas y en los procesos de elaboración y implementación de determinadas políticas (energía y transporte) así como en las relaciones entre sectores de la administración pública y entre el sector público y el privado.

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In this survey, results on the representation of a function as an absolutely convergent Fourier integral are collected, classified and discussed. Certain applications are also given.

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We prove two-sided inequalities between the integral moduli of smoothness of a function on R d[superscript] / T d[superscript] and the weighted tail-type integrals of its Fourier transform/series. Sharpness of obtained results in particular is given by the equivalence results for functions satisfying certain regular conditions. Applications include a quantitative form of the Riemann-Lebesgue lemma as well as several other questions in approximation theory and the theory of function spaces.

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Aquest projecte s’ emmarca dins el camp de la gestió i la planificació del territori. El cas d’ estudi en qüestió es desenvolupa a Playa Tamarindo (Costa Rica). Es realitza una anàlisi de la situació actual i s’ estudia l’ evolució d’ aquesta localitat en els darrers anys. Aquesta anàlisi determina els canvis que han estat presents tant des del punt de vista físic com socioeconòmic, avaluant-els i quantifican-els per poder-los contrastar

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A new quantitative approach of the mandibular sexual dimorphism, based on computer-aided image analysis and elliptical Fourier analysis of the mandibular outline in lateral view is presented. This method was applied to a series of 117 dentulous mandibles from 69 male and 48 female individuals native of Rhenish countries. Statistical discriminant analysis of the elliptical Fourier harmonics allowed the demonstration of a significant sexual dimorphism in 97.1% of males and 91.7% of females, i.e. in a higher proportion than in previous studies using classical metrical approaches. This original method opens interesting perspectives for increasing the accuracy of sex identification in current anthropological practice and in forensic procedures.

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A procedure for the simultaneous analysis of cell-wall polysaccharides, amides and aliphatic polyesters by transmission Fourier transform infrared microspectroscopy (FTIR) has been established for Arabidopsis petals. The combination of FTIR imaging with spectra derivatization revealed that petals, in contrast to other organs, have a characteristic chemical zoning with high amount of aliphatic compounds and esters in the lamina and of polysaccharides in the stalk of the petal. The hinge region of petals was particular rich in amides as well as in vibrations potentially associated with hemicellulose. In addition, a number of other distribution patterns have been identified. Analyses of mutants in cutin deposition confirmed that vibrations of aliphatic compounds and esters present in the lamina were largely associated with the cuticular polyester. Calculation of spectrotypes, including the standard deviation of intensities, allowed detailed comparison of the spectral features of various mutants. The spectrotypes not only revealed differences in the amount of polyesters in cutin mutants, but also changes in other compound classes. For example, in addition to the expected strong deficiencies in polyester content, the long-chain acyl CoA synthase 2 mutant showed increased intensities of vibrations in a wavelength range that is typical for polysaccharides. Identical spectral features were observed in quasimodo2, a cell-wall mutant of Arabidopsis with a defect in pectin formation that exhibits increased cellulose synthase activity. FTIR thus proved to be a convenient method for the identification and characterization of mutants affected in the deposition of cutin in petals.

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We present an open-source ITK implementation of a directFourier method for tomographic reconstruction, applicableto parallel-beam x-ray images. Direct Fourierreconstruction makes use of the central-slice theorem tobuild a polar 2D Fourier space from the 1D transformedprojections of the scanned object, that is resampled intoa Cartesian grid. Inverse 2D Fourier transform eventuallyyields the reconstructed image. Additionally, we providea complex wrapper to the BSplineInterpolateImageFunctionto overcome ITKâeuro?s current lack for image interpolatorsdealing with complex data types. A sample application ispresented and extensively illustrated on the Shepp-Loganhead phantom. We show that appropriate input zeropaddingand 2D-DFT oversampling rates together with radial cubicb-spline interpolation improve 2D-DFT interpolationquality and are efficient remedies to reducereconstruction artifacts.