Search results for "MATRICE"
showing 10 items of 218 documents
Defining relations of minimal degree of the trace algebra of 3 X 3 matrices
2008
The trace algebra Cnd over a field of characteristic 0 is generated by all traces of products of d generic n × n matrices, n, d 2. Minimal sets of generators of Cnd are known for n = 2 and n = 3 for any d as well as for n = 4 and n = 5 and d = 2. The defining relations between the generators are found for n = 2 and any d and for n = 3, d = 2 only. Starting with the generating set of C3d given by Abeasis and Pittaluga in 1989, we have shown that the minimal degree of the set of defining relations of C3d is equal to 7 for any d 3. We have determined all relations of minimal degree. For d = 3 we have also found the defining relations of degree 8. The proofs are based on methods of representati…
A hierarchical-ACA technique for large-scale acoustic simulations: complex geometries with sound adsorbent materials
2012
In this paper a boundary element approach for acoustic simulations based on the hierarchical-matrix format coupled with the adaptive cross approximation (ACA) algorithm and a hierarchical GMRES solver is presented. The cluster tree is generated using preliminary considerations of the prescribed boundary conditions. An improved ACA algorithm, applied, separately, to Neumann, Dirichlet and mixed Robin conditions, is described. Numerical results are presented to show the new approach to be up to 50% faster than conventional ACA approach.
Single hollow fiber SLM extraction of polyamines followed by tosyl chloride derivatization and HPLC determination
2007
Determination of polyamines in biological fluids possesses medical diagnostic relevance. Despite the vast panel of analytical methods developed for polyamines they are not applied in routine clinical usage, mainly due to the time and labor consuming sample preparation step and complicated derivatization procedures. Thus, new simpler methods are needed. This paper describes a single hollow fiber SLM extraction method of polyamines followed by simple pre-column derivatization with tosyl chloride and HPLC-UV analysis. The influence of different parameters such as the extraction time, organic phase composition, acceptor pH, donor pH, acceptor volume, donor volume and stirring speed on the trans…
Prognostic Relevance of CCN3 in Bone Sarcomas
2010
Osteosarcomas and Ewing’s sarcoma (EWS) are aggressive malignant bone tumors. In both cases, prognostic markers are lacking. Presently, only clinical features are widely accepted as prognostic indicators. In this study we assessed the prognostic value of CCN3 (Nov), a matricellular protein that belong to the CCN family of regulatory proteins, whose members were shown to play crucial roles in bone formation. In osteosarcomas, CCN3 expression levels represent a useful tool to early identification of patients with different prognosis. In both osteosarcomas and Ewing’s sarcomas, the expression of a full length CCN3 protein was associated to a worse prognostic and a higher risk to developing met…
La emergencia viral como consecuencia de la interacción entre las variabilidades genéticas del virus y huésped
2015
La variabilidad genética en las poblaciones de huéspedes para la susceptibilidad al patógeno es esencial para la propagación de un virus emergente. Los modelos matemáticos predicen que la tasa de difusión del patógeno se frena a medida que aumenta la frecuencia y la diversidad de alelos de resistencia en la población huésped148,230. Sin embargo, las pruebas experimentales de esta hipótesis son escasas. Por ese motivo, este trabajo aborda la cuestión de cuánta heterogeneidad genética del huésped es necesaria para el cambio del destino evolutivo del virus. El modelo de patosistema experimental utilizado en este trabajo está compuesto por el Virus del grabado del tabaco (TEV), aislado At17b (T…
Principio di costituzionalità e diritto del bilancio
2020
Il principio di costituzionalità è principio di struttura del modello italiano di garanzia giurisdizionale della Costituzione. Esso assicura la più ampia possibilità di sottoporre a giudizio di costituzionalità le norme di un dato ordinamento ed impedisce che il controllo di costituzionalità possa produrre effetti di maggiore o più grave incostituzionalità rispetto a quanto aveva determinato l’esercizio del potere normativo da parte del Legislatore. Il contributo mostra come il sindacato di costituzionalità sul diritto del bilancio si sia svolto al fine di assicurare la massima effettività del principio di costituzionalità rispetto alla Costituzione finanziaria e comeo ciò sia stato possibi…
Hierarchical BEM for dynamic analysis of anisotropic 3-D cracked solids
2011
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…