1,414 research outputs found
Explicit group USSOR method for solving elliptic partial differential equations
This paper presents a new 4-points Explicit Group Unsymmetric
Successive Overrelaxation (USSOR) iterative method to approximate the solution of the
linear systems derived from the discretisation of self-adjoint elliptic partial equations.
Several studies have been carried out by many researchers on the USSOR iterative
method, for example, the analysis of its convergence [1], an upper bound for its error [2]
and recently a special case of the USSOR, namely the SSOR method has been used to
approximate the solution of augmented systems [4] and [8]. The computational behaviour
of this new method and a comparison with its point version is presented
A variant of the AOR method for augmented systems
A variant of the AOR method for augmented system
The explicit group TOR method
The numerical methods for solving partial differential equations have been one of the significant achievements made possible by the digital computers. With the advent of parallel computers, many studies have been performed and a number of new techniques have been investigated in order to develop new methods that are suitable for these computers. One of these techniques is the explicit group iterative methods which have been extensively studied and analysed in the last two decades. The explicit group iterative methods for the numerical solution of self-adjoint elliptic partial differential equations have been introduced (Evans & Biggins, 1982; Yousif & Evans, 1986) and has been shown to be computationally superior in comparison with other iterative methods. These methods were found to be suitable for parallel computers as they possess independent tasks (Evans & Yousif, 1990). Martins, Yousif & Evans (2002) introduced a new explicit 4-points group accelerated overrelaxation (EGAOR) iterative method, a comparison with the point AOR method has shown its computational advantages. The point TOR method was developed and a number of papers related to the TOR method and its convergence have been presented (Kuang & Ji, 1988; Chang, 1996; Chang, 2001; Martins, Trigo & Evans 2003). In this paper, we formulate a new group method from the TOR family, the explicit 4-points group overrrelaxation (EGTOR) iterative method, the derivation of the new method is presented. Numerical experiments have been carried out and the results obtained confirm the superiority of the new method when compared to the point TOR method
Cosmological Consequences of String-forming Open Inflation Models
We present a study of open inflation cosmological scenarios in which cosmic
strings form betwen the two inflationary epochs. It is shown that in these
models strings are stretched outside the horizon due to the inflationary
expansion but must necessarily re-enter the horizon before the epoch of equal
matter and radiation densities. We determine the power spectrum of cold dark
matter perturbations in these hybrid models, finding good agreement with
observations for values of and comparable
contributions from the active and passive sources to the CMB. Finally, we
briefly discuss other cosmological consequences of these models.Comment: 11 LaTeX pages with 3 eps figure
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Pathological gambling subtypes: A comparison of treatment-seeking and non-treatment-seeking samples from Brazil and Canada
Background: Pathological gambling (PG) is a heterogeneous disorder. The identification and characterization of PG subtypes could lead to tailored treatment approaches, which may, in turn, improve treatment outcomes. Objective: To investigate PG subtypes based on personality traits across two different cultural and clinical settings. Consistent with the Pathways Model, we hypothesized the presence of three subtypes (behaviorally conditioned — BC, emotionally vulnerable — EV, and antisocial impulsivist — AI). Methods: 140 PG adults from São Paulo, Brazil (SP sample) and 352 adults with PG (n = 214) or sub-clinical PG (n = 138) from Toronto, Canada (TO sample) completed the Temperament and Character Inventory (TCI). Latent-class analysis was used to investigate subtypes. Results: A 2-class solution was the best model for the pooled SP and TO samples. Class 1 presented a normative personality profile and was composed exclusively of participants from Toronto (BC subtype). Class 2 was characterized by high novelty seeking, high harm avoidance, and low self-directedness, and included participants from both SP and TO (EV subtype). When sub-clinical PGs were excluded from the analysis, a single-class solution better characterized the SP and TO samples. Conclusions: Our results suggest that PG severity, rather than community or clinical settings, may have an effect on PG subtypes. The generalizability of the results is limited by the demographic and clinical features of the selected samples. Future neurobiological studies may contribute to the categorization of subjects into PG subtypes based on different underlying biological pathways
AVALIAÇÃO NUTRITIVA DE FENOS DA PASTAGEM NATURAL DO PARANÁ
Fenos de pastagem natural do Paraná colhidos durante o verão nos municípios de Ponta
Grossa, Guarapuava e Tibagi, foram avaliados pela composição química, determinação dos
coeficientes de digestibilidade e consumo voluntário com ovinos. Baseados na composição química,
os valores encontrados foram semelhantes para os três fenos estudados. No entanto, o feno de
Guarapuava apresentou valores mais elevados em FDN e lignina. Entre os coeficientes de
digestibilidade, somente o da proteína bruta e do FDN não apresentaram diferença significativa entre
os locais (P>0,05). Para a digestibilidade da matéria seca e energia bruta, o feno de Ponta Grossa
mostrou-se superior ao de Tibagi. No consumo de matéria seca, proteína e energia digestíveis, não
houve diferença significativa (P>0,05) entre locais, mas em relação a energia líquida de manutenção
o feno de Ponta Grossa diferiu significativamente do feno de Tibagi (P0.05). As far as digestibility of the dry matter and gross energy are concerned,
the hay of Ponta Grossa showed superior qualities when compared with the Tibagi one. No significant
differences (P>0.05) were found between all the hays studied. However, in regard to liquid
maintenance energy, the Ponta Grossa hay differed significantly from the Tibagi hay (
Microwave-assisted and solvent-free peroxidative oxidation of 1-phenylethanol to acetophenone with a CuII–TEMPO catalytic system
Abstract The water-soluble copper(II) complex [Cu(H2R)(HL)]∙H2O (1) was prepared by reaction of copper(II) nitrate hydrate with (E)-2-(((1-hydroxynaphthalen-2-yl)methylene)amino) benzenesulfonic acid (H2L) and diethanolamine (H3R). It was characterized by IR and ESI-MS spectroscopies, elemental and X-ray crystal structural analyses. 1 shows a high catalytic activity for the solvent-free microwave (MW) assisted oxidation of 1-phenylethanol with tert-butylhydroperoxide, leading, in the presence of TEMPO, to yields up to 85% (TON = 850) in a remarkably short reaction time (15 min, with the corresponding TOF value of 3.40 × 103 h− 1) under low power (25 W) MW irradiation
GD1a modulates GM-CSF-induced cell proliferation
AbstractGangliosides have been extensively described to be involved in the proliferation and differentiation of various cell types, such including hematopoietic cells. Our previous studies on murine models of stroma-mediated myelopoiesis have shown that gangliosides are required for optimal capacity of stromal cells to support proliferation of myeloid precursor cells, being shed to the supernatant and selectively incorporated into myeloid cell membranes. Here we describe the effect of gangliosides on the specific granulocyte–macrophage colony-stimulating factor (GM-CSF)-induced proliferation. For that, we used the monocytic FDC-P1 cell line, which is dependent upon GM-CSF for survival and proliferation. Cells were cultured in the presence of GM-CSF and exogenous gangliosides (GM3, GD1a or GM1) or in the absence of endogenous ganglioside synthesis by the use of a ceramide-synthase inhibitor, d-PDMP. We observed that exogenous addition of GD1a enhanced the GM-CSF-induced proliferation of the FDC-P1 cells. Also, we detected an increase in the expression of the α isoform of the GM-CSF receptor (GMRα) as well as of the transcription factor C/EBPα. On the contrary, inhibition of glucosylceramide synthesis was accompanied by a decrease in cell proliferation, which was restored upon the addition of exogenous GD1a. We also show a co-localization of GD1a and GMR by immunocytochemistry. Taken together, our results suggest for the first time that ganglioside GD1a play a role on the modulation of GM-CSF-mediated proliferative response, which might be of great interest not only in hematopoiesis, but also in other immunological processes, Alzheimer disease, alveolar proteinosis and wherever GM-CSF exerts its effects
Wave profile and tide monitoring system for scalable implementation
Apresentação de Poster em conferência Nacional.Presentation of a wave profile and tide monitoring system, with low-cost and low-power pressure sensors connected to a datalogger in a wired or acustic network
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