Search

El presente artículo tiene como finalidad realizar un análisis sobre el financiamiento público de los partidos políticos en Costa Rica desde una perspectiva jurídica, procurando un abordaje descriptivo y razonado. A partir de este estudio, se pretende desarrollar cómo sería posible una contienda entre partidos políticos más equitativa a través del financiamiento público, visto como una garantía al derecho de elección, a partir del piso presupuestario permitido para que los partidos políticos puedan participar en contiendas electorales

In this paper we present an application of the Generalized Finite Difference Method to solve the generalized nonlinear Benjamin–Bona–Mahony–Burgers equation in 2D and 3D. We provide two approaches to solving the BBMB equation. First, we directly use the explicit GFD scheme, and second, we transform the equation into a PDE system. In a further attempt we find criteria for the convergence of the fully explicit method using GFDM for the Benjamin–Bona–Mahony–Bourgers equation in 2D and 3D. [ABSTRACT FROM AUTHOR]

The generalized finite difference method (GFDM) has been proved to be a good meshless method to solve several linear partial differential equations (PDEs): wave propagation, advection–diffusion, plates, beams, etc. The GFDM allows us to use irregular clouds of nodes that can be of interest for modelling non-linear hyperbolic PDEs. This paper illustrates that the GFD explicit formulae developed to obtain the different derivatives of the PDEs are based on the existence of a positive definite matrix which is obtained using moving least squares approximation and Taylor series development. Consistency and stability are shown in this paper for semilinear and quasilinear hyperbolic equations. This paper shows the application of the GFDM for solving second order non-linear hyperbolic problems. [ABSTRACT FROM AUTHOR]

Abstract The generalized finite difference method (GFDM) has been proved to be a good meshless method to solve several linear partial differential equations (PDEs): wave propagation, advection–diffusion, plates, beams, etc. The GFDM allows us to use irregular clouds of nodes that can be of interest for modelling non-linear parabolic PDEs. This paper illustrates that the GFD explicit formulae developed to obtain the different derivatives of the pde's are based in the existence of a positive definite matrix that it is obtained using moving least squares approximation and Taylor series development. Criteria for convergence of fully explicit method using GFDM for different non linear parabolic PDEs are given. This paper shows the application of the GFDM to solving different non-linear problems including applications to heat transfer, acoustics and problems of mass transfer. [ABSTRACT FROM AUTHOR]

The generalized finite difference method (GFDM) has been proved to be a good meshless method to solve several linear partial differential equations (pde’s): wave propagation, advection–diffusion, plates, beams, etc. The GFDM allows us to use irregular clouds of nodes that can be of interest for modelling non-linear elliptic pde’s. This paper illustrates that the GFD explicit formulae developed to obtain the different derivatives of the pde’s are based on the existence of a positive definite matrix that it is obtained using moving least squares approximation and Taylor series development. Also it is shown that in 2D a regular neighbourhood of eight nodes can be regarded as a generalization of a classical finite difference formula with a sixth order truncation error. This paper shows the application of the GFDM to solving different non-linear problems including applications to heat transfer, acoustics and problems of mass transfer. [ABSTRACT FROM AUTHOR]

Abstract: This paper shows the application of the generalized finite difference method (GFDM) to the problem of dynamic analysis of beams and plates. The stability conditions for a fully explicit algorithm are given for beams and plates. Measures of the irregularity of the clouds of points for beams and plates are given. Various cases of vibrations of beams and plates have been solved and the results show the accuracy of the method for irregular clouds of nodes. [Copyright &y& Elsevier]

Abstract: The interior of the Earth is heterogeneous with different materials and may have complex geometry. The free surface can also be uneven. Therefore, the use of a meshless method “with the possibility of using an irregular grid-point distribution” can be of interest for modelling this kind of problem. This paper shows the application of GFDM to the problem of seismic wave propagation in 2-D. To use this method in unbounded domains one must truncate the computational grid-point avoiding reflection from the edges. PML absorbing boundary condition has then been included in the numerical model proposed in this work. [Copyright &y& Elsevier]

In this paper, the extension of the generalized finite difference method to the solution of anisotropic elliptical and parabolic partial differential equations is given in the case of considering two space dimensions. The explicit finite difference formulae and the criterion of stability for the anisotropic parabolic equations are given. The stability condition has been expressed in function of the coefficients of the star equation for irregular clouds of nodes. Various anisotropic cases of simulation of cardiac tissue, including elliptic and parabolic equations, have been solved, and the results show the accuracy of the method. [ABSTRACT FROM PUBLISHER]

A survey of the Cambridge Crystallographic Database reveals that there are 17 1H-indazoles forming dimers (7), trimers (4) and catemers or chains (6). Amongst the catemers there is one centrosymmetric compound and five non-centrosymmetric ones that crystallize in chiral helices, either M or P, including indazole itself, whose structure has been determined anew. An explanation will be provided for how an achiral molecule crystallizes in a chiral space group. The second part of the paper is devoted to the use of Vibrational Circular Dichroism (VCD) for determining the absolute configuration of a crystal of indazole. This previously needs the complete assignment of its IR and Raman spectra in solution and in the solid-state based on B3LYP/6-31G(d) calculations of indazole dimers and trimers, which are already chiral. [ABSTRACT FROM AUTHOR]

Abstract: Classical finite difference schemes are in wide use today for approximately solving partial differential equations of mathematical physics. An evolution of the method of finite differences has been the development of generalized finite difference (GFD) method, that can be applied to irregular grids of points. In this paper the extension of the GFD to the explicit solution of parabolic and hyperbolic equations has been developed for partial differential equations with constant coefficients in the cases of considering one, two or three space dimensions. The convergence of the method has been studied and the truncation errors over irregular grids are given. Different examples have been solved using the explicit finite difference formulae and the criterion of stability. This has been expressed in function of the coefficients of the star equation for irregular clouds of nodes in one, two or three space dimensions. The numerical results show the accuracy obtained over irregular grids. This paper also includes the study of the maximum local error and the global error for different examples of parabolic and hyperbolic time-dependent equations. [Copyright &y& Elsevier]

Abstract: The joint experimental and theoretical study of the vibrational spectra of the molecular series (CH3)3SiX (with X=H, F and Br) is carried out. Data from newly recorded IR and Raman spectra for the bromo derivative, experimental data obtained previously for the remaining species, DFT theoretical calculations and the use of the SQMFF procedure have allowed us to propose common patterns and to unify criteria in their assignment. In addition, two sets of averaged scale factors for the B3LYP force field obtained with two different basis sets (6-31G* and DZP+diff) have been proposed for the common bulky moiety of that molecular series. These parameters were used successfully in order to reproduce the frequency of the bands assigned to the (CH3)3Si– group in the vibrational spectra of the corresponding silanolic and methoxy derivatives, i.e., trimethylsilanol and methoxytrimethylsilane, proving their transferability. [Copyright &y& Elsevier]

This paper shows the explicit formulae for the generalized finite difference method in the three-dimensional case. The method solves different types of partial differential equations for irregular clouds of nodes. The explicit difference formulae obtained make it possible to propose a posteriori error indicator (taking more terms of the Taylor's series expansion). This serves as a starting point for an h-adaptive method to improve the solution by selectively adding nodes to the domain. The h-adaptive method consists in marking the nodes with an indicated error higher than a provided limit. Then, several nodes can be added to each star with a marked central node and placed centrally between this and the star nodes with greater indicator errors. This paper analyses the results obtained using the h-adaptive method in several cases and shows how the solution error decreases. It also analyses the influence of key parameters involved, and the quality of the error estimate. [ABSTRACT FROM AUTHOR]

A new proposal of vibrational assignment for pyridine is reported. Infrared spectra for the liquid and gas phases as well as Raman spectra for the liquid have been recorded and analyzed for -d0, -d5 and, for the first time to our knowledge, for 15N isotopomers as well. The proposal of assignment has been assessed by the calculation of a number of force fields, theoretical (ab initio, density functional theory) approaches as well as by a set of simple valence internal coordinates force constants transferred from benzene using the pure vibrational force field approximation. In all cases, the root mean square (rms) for the wavenumbers turn out to be lower than the best obtained so far, i.e. 6.6 cm−1, as stated by Wiberg et al. [Copyright &y& Elsevier]

We derive a discretization of the Caputo and Riemann–Liouville spatial derivatives by means of the meshless Generalized Finite Difference Method, which is based on moving least squares. The conditional convergence of the method is proved and several examples over one dimensional irregular meshes are given. [ABSTRACT FROM AUTHOR]