Multidimensional parametric quantum solitons

We consider the parametric quantum field theory involving cubic and quartic couplings of two bosonic fields. This is exactly soluble for the two-particle energy eigenstates (or quantum solitons) in one, two, and three space dimensions. We estimate the binding energies and corresponding radii in the case of photonic fields in nonlinear optical materials, and Bose-Einstein condensates. [S1050-2947(98)51110-9].

Theory of multidimensional parametric band-gap simultons

Multidimensional spatiotemporal parametric simultons (simultaneous solitary waves) are possible in a nonlinear chi((2)) medium with a Bragg grating structure, where large effective dispersion occurs near two resonant band gaps for the carrier and second-harmonic field, respectively. The enhanced dispersion allows much reduced interaction lengths, as compared to bulk medium parametric simultons. The nonlinear parametric band-gap medium permits higher-dimensional stationary waves to form. In addition, solitons can occur with lower input powers than conventional nonlinear Schrodinger equation gap solitons. In this paper, the equations for electromagnetic propagation in a grating structure with a parametric nonlinearity are derived from Maxwell's equation using a coupled mode Hamiltonian analysis in one, two, and three spatial dimensions. Simultaneous solitary wave solutions are proved to exist by reducing the equations to the coupled equations describing a nonlinear parametric waveguide, using the effective-mass approximation (EMA). Exact one-dimensional numerical solutions in agreement with the EMA solutions are also given. Direct numerical simulations show that the solutions have similar types of stability properties to the bulk case, providing the carrier waves are tuned to the two Bragg resonances, and the pulses have a width in frequency space less than the band gap. In summary, these equations describe a physically accessible localized nonlinear wave that is stable in up to 3 + 1 dimensions. Possible applications include photonic logic and switching devices. [S1063-651X(98)06109-1].

Multidimensional quantum solitons with nondegenerate parametric interactions: Photonic and Bose-Einstein condensate environments

We consider the quantum theory of three fields interacting via parametric and repulsive quartic couplings. This can be applied to treat photonic chi((2)) and chi((3)) interactions, and interactions in atomic Bose-Einstein condensates or quantum Fermi gases, describing coherent molecule formation together with a-wave scattering. The simplest two-particle quantum solitons or bound-state solutions of the idealized Hamiltonian, without a momentum cutoff, are obtained exactly. They have a pointlike structure in two and three dimensions-even though the corresponding classical theory is nonsingular. We show that the solutions can be regularized with a momentum cutoff. The parametric quantum solitons have much more realistic length scales and binding energies than chi((3)) quantum solitons, and the resulting effects could potentially be experimentally tested in highly nonlinear optical parametric media or interacting matter-wave systems. N-particle quantum solitons and the ground state energy are analyzed using a variational approach. Applications to atomic/molecular Bose-Einstein condensates (BEC's) are given, where we predict the possibility of forming coupled BEC solitons in three space dimensions, and analyze superchemistry dynamics.

Using multidimensional projection techniques for reaching a high distinguishing ability in biosensing

Recent advances in the control of molecular engineering architectures have allowed unprecedented ability of molecular recognition in biosensing, with a promising impact for clinical diagnosis and environment control. The availability of large amounts of data from electrical, optical, or electrochemical measurements requires, however, sophisticated data treatment in order to optimize sensing performance. In this study, we show how an information visualization system based on projections, referred to as Projection Explorer (PEx), can be used to achieve high performance for biosensors made with nanostructured films containing immobilized antigens. As a proof of concept, various visualizations were obtained with impedance spectroscopy data from an array of sensors whose electrical response could be specific toward a given antibody (analyte) owing to molecular recognition processes. In addition to discussing the distinct methods for projection and normalization of the data, we demonstrate that an excellent distinction can be made between real samples tested positive for Chagas disease and Leishmaniasis, which could not be achieved with conventional statistical methods. Such high performance probably arose from the possibility of treating the data in the whole frequency range. Through a systematic analysis, it was inferred that Sammon`s mapping with standardization to normalize the data gives the best results, where distinction could be made of blood serum samples containing 10(-7) mg/mL of the antibody. The method inherent in PEx and the procedures for analyzing the impedance data are entirely generic and can be extended to optimize any type of sensor or biosensor.

MULTIDIMENSIONAL SCALING OF MUSICAL TIME ESTIMATIONS

The aim of this study was to identify the psycho-musical factors that govern time evaluation in Western music from baroque, classic, romantic, and modern repertoires. The excerpts were previously found to represent variability in musical properties and to induce four main categories of emotions. 48 participants (musicians and nonmusicians) freely listened to 16 musical excerpts (lasting 20 sec. each) and grouped those that seemed to have the same duration. Then, participants associated each group of excerpts to one of a set of sine wave tones varying in duration from 16 to 24 sec. Multidimensional scaling analysis generated a two-dimensional solution for these time judgments. Musical excerpts with high arousal produced an overestimation of time, and affective valence had little influence on time perception. The duration was also overestimated when tempo and loudness were higher, and to a lesser extent, timbre density. In contrast, musical tension had little influence.

Spatiotemporal solitons in multidimensional optical media with a quadratic nonlinearity

We consider solutions to the second-harmonic generation equations in two-and three-dimensional dispersive media in the form of solitons localized in space and time. As is known, collapse does not take place in these models, which is why the solitons may be stable. The general solution is obtained in an approximate analytical form by means of a variational approach, which also allows the stability of the solutions to be predicted. Then, we directly simulate the two-dimensional case, taking the initial configuration as suggested by the variational approximation. We thus demonstrate that spatiotemporal solitons indeed exist and are stable. Furthermore, they are not, in the general case, equivalent to the previously known cylindrical spatial solitons. Direct simulations generate solitons with some internal oscillations. However, these oscillations neither grow nor do they exhibit any significant radiative damping. Numerical solutions of the stationary version of the equations produce the same solitons in their unperturbed form, i.e., without internal oscillations. Strictly stable solitons exist only if the system has anomalous dispersion at both the fundamental harmonic and second harmonic (SH), including the case of zero dispersion at SH. Quasistationary solitons, decaying extremely slowly into radiation, are found in the presence of weak normal dispersion at the second-harmonic frequency.

A multidimensional approach to the group cohesion-group performance relationship

This study (a) examined the multidimensionality of both group cohesion and group performance, (b) investigated the relationship between group-level task and social cohesion and group effectiveness, and (c) examined the longitudinal changes in cohesion and performance and the direction of effect between cohesion and performance. First, the authors hypothesized that both task and social cohesion would predict positively all dimensions of group performance. Second, that a stronger relationship would be observed between task cohesion and task effectiveness and between social cohesion and system viability. Third, that all dimensions of cohesion and performance would increase over time. Finally, that cohesion would be both the antecedent and the consequence of performance but that the performance-cohesion relationship would be stronger than the cohesion-performance relationship. Results supported the hypothesized one-to-one relationship between specific dimensions of group cohesion and group performance. Task cohesion was the sole predictor of self-rated performance at both Time 1 and Time 2, whereas social cohesion was the only predictor of system viability at Time 1 and the stronger predictor at Time 2. Social cohesion at Time 2 predicted performance on group task. However, no longitudinal changes were found in cohesion or performance. Finally, group cohesion was found to be the antecedent, but not the consequence, of group performance.

Mean anisotropy of homogeneous Gaussian random fields and anisotropic norms of linear translation-invariant operators on multidimensional integer lattices

Sensitivity of output of a linear operator to its input can be quantified in various ways. In Control Theory, the input is usually interpreted as disturbance and the output is to be minimized in some sense. In stochastic worst-case design settings, the disturbance is considered random with imprecisely known probability distribution. The prior set of probability measures can be chosen so as to quantify how far the disturbance deviates from the white-noise hypothesis of Linear Quadratic Gaussian control. Such deviation can be measured by the minimal Kullback-Leibler informational divergence from the Gaussian distributions with zero mean and scalar covariance matrices. The resulting anisotropy functional is defined for finite power random vectors. Originally, anisotropy was introduced for directionally generic random vectors as the relative entropy of the normalized vector with respect to the uniform distribution on the unit sphere. The associated a-anisotropic norm of a matrix is then its maximum root mean square or average energy gain with respect to finite power or directionally generic inputs whose anisotropy is bounded above by a≥0. We give a systematic comparison of the anisotropy functionals and the associated norms. These are considered for unboundedly growing fragments of homogeneous Gaussian random fields on multidimensional integer lattice to yield mean anisotropy. Correspondingly, the anisotropic norms of finite matrices are extended to bounded linear translation invariant operators over such fields.

Indicadores e Análise Multidimensional do Processo de Integração do Cone Sul

No trabalho são desenvolvidos indicadores de integração regional com o principal objetivo de apresentar uma analise multidimensional do Mercosul no período de 1991 a 2006. A pesquisa parte da premissa que o Mercosul não é um caso sui generis de integração regional, e sim um exemplo de organização de integração regional assim como, por exemplo, a União Européia ou a Comunidade Andina de Nações. Assim, embora os indicadores sejam desenvolvidos para serem aplicados no Mercosul, eles poderiam potencialmente ser aplicados para outros casos de processos de integração regional.

Los modelos CAMEL y Promethee como instrumentos de análisis de la banca virtual en España

Consideramos de interés realizar un análisis financiero de la banca virtual en España para ser capaces de posicionar aquellas entidades bancarias que vieron en el canal de Internet una vía de expansión hacia nuevos clientes o como consolidación de los existentes, ya que todos los bancos creados en España de carácter virtual son filiales de grandes grupos bancarios. Utilizamos como modelos de análisis la aplicación de los métodos multicriterio CAMEL y Promethee. Como conclusiones del trabajo se observa que, independientemente del método utilizado, la entidad que mejor se posiciona para el periodo de análisis estudiado (2004-2010) es Bancopopular-e. No obstante, son entidades que todavía alcanzan valores muy bajas de rentabilidad y liquidez y donde datos como la eficiencia o la calidad de activos son muy mejorables.

Factores determinantes del grado de información medioambiental divulgada en las grandes empresas que operan en Portugal: un análisis univariante

El presente trabajo tiene un doble objetivo: por un lado, analizar el grado en que una muestra de grandes empresas que operan en Portugal divulgan información medioambiental en sus informes anuales y su evolución durante el período 2002-2004 y, por otro, identificar los factores que influyen en dicho grado de divulgación, a través de un análisis univariante. A partir del análisis de contenido de los informes anuales, se elaboró un Índice de Divulgación Medioambiental (IDMA). Los resultados obtenidos indican que, si bien el valor medio del IDMA es relativamente bajo, éste ha evolucionado positivamente durante el período analizado. El análisis univariante ha permitido identificar la existencia de una asociación significativa entre el IDMA y las variables tamaño, cotización en bolsa, posesión de certificación medioambiental y pertenencia a un sector considerado “crítico”.

El Cuadro de Mando Integral en Organizaciones Privadas Portuguesas: Un Análisis Descriptivo

La creencia de que los modelos existentes para evaluación del desempeño empresarial eran obsoletos y podían llevar a las empresas a tomar decisiones erróneas llevaron al desarrollo de sistemas de información y control de gestión que reflejen la evolución de los factores clave de éxito de naturaleza no financiera y/o cualitativa, como es el caso del Cuadro de Mando Integral (CMI). El CMI es una de las herramientas de Contabilidad de Gestión más populares en la actualidad. Al mismo tiempo hay informes de altas tasas de fracaso lo que exige mirar con mayor detenimiento los retos y los principales problemas que distintas organizaciones privadas han encontrado en su implementación. En consecuencia, mismo después de más de dos décadas de existencia, y a pesar de las mejoras registradas en el modelo, se verifica en el ámbito empresarial y académico una continuidad de la inversión en proyectos de CMI. Así, con el objetivo de averiguar si las organizaciones portuguesas conocen y están a adoptar el CMI, hemos enviado un cuestionario a 549 organizaciones privadas, con una tasa de respuesta del 28,2%. Los resultados obtenidos permiten concluir que aunque la mayoría de los encuestados conoce el CMI, su utilización en dichas organizaciones es reducida y muy reciente.

El Cuadro de Mando Integral en Organizaciones Públicas Portuguesas: Un Análisis Descriptivo

En el actual contexto de mayor responsabilidad y transparencia en la gestión pública, las organizaciones del sector público tienen presente la necesidad de mejorar la eficiencia en la aplicación de los recursos y la provisión de servicios a los usuarios. Ante esta situación, existe la necesidad de desarrollar sistemas de información y control de gestión que reflejen la evolución de los factores clave de éxito de naturaleza no financiera y/o cualitativa, como es el caso del Cuadro de Mando Integral (CMI). Así, con el objetivo de averiguar si conocen y están a adoptar el CMI, cuales las principales motivaciones para su aplicación y cómo se está implementando, hemos enviado un cuestionario a 591 organizaciones públicas, con una tasa de respuesta del 34%. Los resultados obtenidos permiten concluir que aunque la mayoría de los encuestados conoce el CMI, su utilización en dichas organizaciones es reducida y muy reciente.

El Cuadro de Mando Integral en Organizaciones Privadas Portuguesas: Un Análisis Descriptivo

La creencia de que los métodos existentes para evaluación del desempeño empresarial eran obsoletos y podían llevar a las empresas a tomar decisiones erróneas llevaron al desarrollo de sistemas de información y control de gestión que reflejen la evolución de los factores clave de éxito de naturaleza no financiera y/o cualitativa, como es el caso del Cuadro de Mando Integral. Así, con el objetivo de averiguar si conocen y están a adoptar el CMI, hemos enviado un cuestionario a 549 organizaciones privadas, con una tasa de respuesta del 28,2%. Los resultados obtenidos permiten concluir que aunque la mayoría de los encuestados conoce el CMI, su utilización en dichas organizaciones es reducida y muy reciente.

El Cuadro de Mando Integral en Organizaciones Públicas Portuguesas: Un Análisis Descriptivo

En el actual contexto de mayor responsabilidad y transparencia en la gestión pública, las organizaciones del sector público tienen presente la necesidad de mejorar la eficiencia en la aplicación de los recursos y la provisión de servicios a los usuarios. Ante esta situación, existe la necesidad de desarrollar sistemas de información y control de gestión que reflejen la evolución de los factores clave de éxito de naturaleza no financiera y/o cualitativa, como es el caso del Cuadro de Mando Integral (CMI). Así, con el objetivo de averiguar si conocen y están a adoptar el CMI, cuales las principales motivaciones para su aplicación y como está a ser implementado, hemos enviado un cuestionario a 591 organizaciones públicas, con una tasa de respuesta del 34%. Los resultados obtenidos permiten concluir que aunque la mayoría de los encuestados conoce el CMI, su utilización en dichas organizaciones es reducida y muy reciente.