Search results for "Matrices"
showing 10 items of 155 documents
On a limiting distribution of singular values of random band matrices
2015
An equation is obtained for the Stieltjes transform of the normalized dis- tribution of singular values of non-symmetric band random matrices in the limit when the band width and rank of the matrix simultaneously tend to infinity. Conditions under which this limit agrees with the quarter-circle law are found. An interesting particular case of lower triangular random matri- ces is also considered and certain properties of the corresponding limiting singular value distribution are given.
Modelling of rotations by using matrix solutions of nonlinear wave equations
2007
A family of matrix solutions of nonlinear wave equations is extended and its application to modelling is given. It is shown that a similarity transformation, induced by the matrix solution, is equivalent to the rotation. Matrix solutions are used for modelling helical motions and vortex rings, simultaneous rotations and particles collision, mapping contraction and pulsating spheres. Geometrical interpretation of the doubling of rotation angle in each step of sequential mapping contraction is given. First Published Online: 14 Oct 2010
EFFECTIVENESS OF BASALT FIBRE-REINFORCED CEMENTITIOUS SYSTEMS IN CONFINING MASONRY MEMBERS: AN EXPERIMENTAL INVESTIGATION
2020
The use of composites based on fibre-reinforced polymers (FRPs) to strengthen masonry columns has become a common practice in the last decades. FRPs, however, exhibit some shortcomings when applied to masonry substrates, due to the organic nature of their matrix. For this reason, increasing attention is paid today to composites based on fibre-reinforced cementitious matrices (FRCMs), in which the polymeric matrix is replaced with an inorganic matrix (such as cementitious mortars). Cementitious matrices guarantee higher breathability and compatibility with the substrate, less sensitivity to debonding at the interfaces, and higher resistance to fire and high temperatures. Moreover, due to the…
Aplicación de Sistemas Multiagentes para la obtención de matrices Origen-Destino dinámicas mediante el empleo de sensores Bluetooth adaptada al equip…
2015
Los primeros sistemas de gestión del tráfico se basaban en la instalación de elementos de sensorización, espiras magnéticas, que suministraban datos básicos de tráfico como son la intensidad y la velocidad, integradas en periodos predefinidos y clasificadas en varias categorías, además de la ocupación y la distancia entre vehículos. Estos datos básicos fueron utilizados para estimar otros parámetros como el nivel de servicio o el tiempo de viaje de cada tramo de la red sensorizada (Lindveld & Thijs, 1999). Además, aplicando una serie de algoritmos a estos datos se realizaba la detección de congestiones o incidentes (Collins et al., 1979). Sin embargo, la estimación del tiempo de viaje no si…
Nanocomposites: Síntesis, caracterización y aplicaciones
2018
En las últimas décadas la nanotecnología ha avanzado a una velocidad vertiginosa, haciendo posible la manipulación de las propiedades de los materiales al controlar la materia a niveles nanométricos y logrando metas impensables hasta hace unas pocas décadas. Sin embargo, al tratarse de una ciencia relativamente reciente, queda mucho potencial por explotar. Es indispensable un avance científico multidisciplinar para lograr superar con éxito las actuales limitaciones tecnológicas para que continúe el progreso. Para ello serán indispensables tanto la obtención de nuevos materiales con propiedades manipulables, como el desarrollo de métodos de fabricación que permitan integrar estos materiales …
Evaluation of efficacy and biocompatibility of a novel semisynthetic collagen matrix as a dural onlay graft in a large animal model
2011
Background Semisynthetic collagen matrices are promising duraplasty grafts with low risk of cerebrospinal fluid (CSF) fistulas, good tissue integration and minor foreign body reaction. The present study investigates the efficacy and biocompatibility of a novel semisynthetic bilayered collagen matrix (BCM, B. Braun Aesculap) as dural onlay graft for duraplasty. Methods Thirty-four pigs underwent osteoclastic trepanation, excision of the dura, and placement of a cortical defect, followed by duraplasty using BCM, Suturable DuraGen™ (Integra Neuroscience), or periosteum. CSF tightness and intraoperative handling of the grafts were evaluated. Pigs were sacrificed after 1 and 6 months for histolo…
Cognitive impairment in patients suffering from relapsing-remitting multiple sclerosis with EDSS ≤ 3.5
2003
Objectives – Previous papers have mainly demonstrated the presence and the frequency of cognitive impairment in patients suffering from relapsing-remitting multiple sclerosis. The purpose of this study was to investigate subjects with the relapsing-remitting form of the disease and mild clinical disability (EDSS ≤ 3.5), so as to quantify this deficit when the illness does not yet interfere with daily living and the ability to work. Methods – Fifty patients and 50 healthy controls were submitted to a wide neuropsychological battery, including Wechsler Memory Scale – I- (WMS), Benton Visual Retention Test – D- (BVRT), Raven Coloured Progressive Matrices (RCPM), Kohs’ test (KT), Judgement of L…
Systematic review and meta-analysis found that malnutrition was associated with poor cognitive development
2021
Aim: Malnutrition is a major public health issue that has been associated with high susceptibility for impaired brain development and mental functioning. However, to date studies on this topic have not been collated and appraised. This systematic review and meta-analysis investigated the association between malnutrition and cognitive development. Methods: We searched the MEDLINE, Scopus, CINAHL, Embase PsycINFO and Cochrane Library databases in English up to 8 December 2020. All studies reporting an association between nutritional status and cognitive development were included. p values of less than 0.05 were considered statistically significant and the results are reported as standardised …
Metathese et homonymie en hebreu biblique
2009
La théorie des matrices et des étymons (Bohas, 1997, 2000) permet de rendre compte d’une organisation formelle et conceptuelle du lexique de l’arabe fondée sur deux aspects essentiels: l’un concerne l’identification du lien lexicologique entre les mots (i. e. présence simultanée d’un invariant formel et d’une ressemblance conceptuelle); le deuxième vise le rapport existant entre ces mots et le monde (i. e. présence d’une charge mimophonique qui suggère, par les séquences articulatoires des mots, certains aspects de la réalité à désigner). Ce modèle s’avère particulièrement intéressant pour d’autres systèmes linguistiques, en l’occurrence, l’hébreu biblique (Dat 2002), car il est à même d’or…
O analogiji i teoriji etimona u hebrejskome biblijskom leksiku
2012
Dans le débat sur l’iconicité du langage, l’une des questions qui se posent d’une manière récurrente est de savoir si les formations onomatopéiques représentent un principe primitif de formation des mots, si dans les premières formes du langage humain tous les signes ont été du type craquer, murmurer, etc., dont la plupart auraient ensuite perdu leur charge mimophonique. Saussure s’est prononcé contre toute théorie positive de la signification dans le domaine des sciences du langage, position qui a constitué pour longtemps une norme de travail en linguistique. Cet article traite des icônes auditives dans le lexique hébraïque de la Bible dont l’analogie phonation–référent est rendue manifest…