991 resultados para Classificació AMS::05 Combinatorics


Relevância:

20.00% 20.00%

Publicador:

Resumo:

We consider the raise and peel model of a one-dimensional fluctuating interface in the presence of an attractive wall. The model can also describe a pair annihilation process in disordered unquenched media with a source at one end of the system. For the stationary states, several density profiles are studied using Monte Carlo simulations. We point out a deep connection between some profiles seen in the presence of the wall and in its absence. Our results are discussed in the context of conformal invariance ( c = 0 theory). We discover some unexpected values for the critical exponents, which are obtained using combinatorial methods. We have solved known ( Pascal`s hexagon) and new (split-hexagon) bilinear recurrence relations. The solutions of these equations are interesting in their own right since they give information on certain classes of alternating sign matrices.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Magnetic fabric and rock magnetism studies were performed on apparently isotropic granite facies from the main intrusion of the Lavras do Sul Intrusive Complex pluton (LSIC, Rio Grande do Sul, South Brazil). This intrusion is roughly circular (similar to 12 x 13.5 km), composed of alkali-calcic and alkaline granitoids, with the latter occupying the margin of the pluton. Magnetic fabrics were determined by applying both anisotropy of low-field magnetic susceptibility (AMS) and anisotropy of anhysteretic remanent magnetization (AARM). The two fabrics are coaxial. The parallelism between AMS and AARM tensors excludes the presence of a single domain (SD) effect on the AMS fabric of the granites. Several rock-magnetism experiments performed in one specimen from each sampled site show that for all sites the magnetic susceptibility is dominantly carried by ferromagnetic minerals, while mainly magnetite carries the magnetic fabrics. Lineations and foliations in the granite facies were successful determined by applying magnetic methods. Magnetic lineations are gently plunging and roughly parallel to the boundaries of the pluton facies, except at the few sites in the central facies which have a radial orientation pattern. In contrast, the magnetic foliations tend to follow the contacts between the different granite facies. They are gently outerward-dipping inside the pluton, and become either steeply southwesterly dipping or vertical towards its margin. The lack of solid-state and subsolidus deformations at outcrop scale and in thin sections precludes deformation after full crystallization of the pluton. This evidence allows us to interpret the observed magnetic fabrics as primary in origin (magmatic) acquired when the rocks were solidified as a result of processes reflecting magma flow. The foliation pattern displays a dome-shaped form for the main LSIC-pluton. However, the alkaline granites which outcrop in the southern part of the studied area have an inward-dipping foliation, and the steeply plunging magnetic lineation suggests that this area could be part of a feeder zone. The magma ascent probably occurred due to ring-diking. (C) 2008 Elsevier B.V. All rights reserved.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

We extend the renormalization operator introduced in [A. de Carvalho, M. Martens and M. Lyubich. Renormalization in the Henon family, I: universality but non-rigidity. J. Stat. Phys. 121(5/6) (2005), 611-669] from period-doubling Henon-like maps to Henon-like maps with arbitrary stationary combinatorics. We show that the renonnalization picture also holds in this case if the maps are taken to be strongly dissipative. We study infinitely renormalizable maps F and show that they have an invariant Cantor set O on which F acts like a p-adic adding machine for some p > 1. We then show, as for the period-doubling case in the work of de Carvalho, Martens and Lyubich [Renormalization in the Henon family, I: universality but non-rigidity. J. Stat. Phys. 121(5/6) (2005), 611-669], that the sequence of renormalizations has a universal form, but that the invariant Cantor set O is non-rigid. We also show that O cannot possess a continuous invariant line field.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Perspective is a periodic publication of the College produced by the Office of Communications.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Apresentamos neste trabalho os resultados de um estudo experimental e teórico dos compostos borocarbetos supercondutores da série Y(Ni1-xMnx)2B2C com x = 0; 0,01; 0,025; 0,05; 0,10; 0,15. A principal motivação para este trabalho foi investigar a estrutura eletrônica e a possível formação do momento magnético sobre os átomos de impureza de Mn nos compostos Y(Ni1- xMnx)2B2C. O aparecimento do momento magnético localizado no sítio da impureza possibilitou estudar a influência do Mn sobre o mecanismo de quebra de pares supercondutores e sobre as propriedades magnéticas do composto. Os borocarbetos são compostos de estrutura cristalina tetragonal de corpo centrado e altamente anisotrópicos (c/a~3). São intermetálicos de alta temperatura crítica supercondutora Tc, com forte acoplamento elétron-fonon. Em alguns casos podem apresentar ordem magnética, supercondutividade e também coexistência ou competição energética entre ambos. As medidas de transporte eletrônico, em função da temperatura, foram feitas utilizando-se um detector síncroton baseado na técnica de quatro pontos operando na faixa de 4,2K até 300K. Essas medidas possibilitaram o estudo das propriedades relacionadas ao transporte eletrônico na fase supercondutora. Na fase normal, extraiu-se a dependência em energia da função espectral de fonons α² F (ω) para alguns compostos da série estudada. As medidas magnéticas em função da temperatura e do campo magnético foram feitas utilizando-se um SQUID (Superconducting Quantun Interference Device – Quantun Design Model MPMS XL). Tais medidas permitiram a caracterização das propriedades magnéticas de nossas amostras. Em particular determinou-se o valor, em regime de saturação, do momento magnético associado ao sítio cristalino do Mn. Foram determinadas também as correntes críticas supercondutoras usando o Modelo de estado crítico de Bean e a variação da temperatura crítica supercondutora (Tc) com a mudança do campo externo aplicado. As medidas magnéticas permitiram a obtenção do diagrama que relaciona o campo crítico inferior (HC1) e a temperatura, variando-se a concentração do átomo dopante de manganês. Foi feito um esforço teórico no sentido de interpretar os resultados experimentais. Para isso foram usados três modelos: O modelo de estado crítico de Bean já citado acima e um modelo baseado na fórmula de Ziman usando uma aproximação para a função espectral de fonons para descrever a resistividade no regime de alta temperatura. Além disto, usou-se o modelo de duas sub-redes para a descrição do momento magnético das impurezas de Mn, em função da concentração, na série Y(Ni ) ( 2 ω α F 1-xMnx)2B2C.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Desenvolvem-se neste artigo as bases teóricas da contabilidade com juros reais. A Seção 11 apresenta uma evidência empírica que corrobora, do ponto de vista macroeconômico, a utilização de juros reais no cálculo do déficit público. A Seção 111 descreve a metodologia de cálculo com juros reais. Inicialmente apenas no tocante aos ativos financeiros denominados em moeda doméstica e, em seguida, analisando tambem o caso em que tais ativos se denominam em moeda estrangeira. As seções IV e V visam apenas a exemplificar, tomando-se como base as contas do setor público brasileiro, a utilização da metodologia aqui apresentada. Calcula-se aí, a partir dos dados da dívida líquida do setor público publicados pelo Banco Central, o deficit real do governo e a diferença entre juros nominais e reais liquidamente pagos pela dívida pública. A seção VI• apresenta uma série histórica de imposto inflacionário e transferência inflacionária (a favor dos bancos comerciais) para o Brasil. A Seção VII estende toda a metodologia de cálculo com juros reais à Contabilidade Social. Introduz-se também a contabilidade operacional, onde a discriminação entre juros reais e nominais se estende a todos os ativos financeiros da economia, exceto ã base monetária. Um resultado importante dessa seção é mostrar que as tautologias usualmente utilizadas nas Contas Nacionais são válidas em qualquer contabilidade, seja ela nominal, real ou operacional. Por último, a Seção VIII mostra que todo este arcabouço pode ser visualizado como uma extensão dos mecanismos de correção de lucros das empresas, amplamente utilizados no Brasil desde 1964.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Zélia Moreira Rebello de Mendonça (3ª pessoa da esquerda para direita)

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Funding was obtained from a Capes Fellowship to NM, grants CNPq Universal 481351/ 2011-6, CNPq PQ 306604/2012-4, FAPERN/CNPq Pronem 003/2011, Capes SticAmSud, and FAPESP/CEPID/Neuromat to S.R. CNPq Universal 473554/2011-9 and 480053/ 2013-8, CNPq PQ 308558/2011-1, FACEPE/CNPq-PRONEX APQ- 0203-1.05/08, FACEPE/CNPq-PRONEM APQ-1415-1.05/10, and CNAIPS to M.C

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Analysis of the elements of the Constitutional Order of the letter 1988 politics, with emphasis in the principles of this, a study on the intervention of the State in the private initiative by means of the Law of Recovery of Companies and Bankruptcies (law 11.101/05). New enterprise vision is admitted, over all in the interdependence between economic and social factors. Study on the globalization and the interdependence of economic and legal sciences in the construction of a legal optics in the search for the economic and social development, with the recognition of the interference of the Economy in the Right and its uneven importance. Still, we delineate the state intervention in the economic scope, of company and in the judicial recovery, as well as the consequences of such intervention in the involved credits in the judicial recovery and patrimony of the debtor in recovery. For such task, the elements of the Judicial Recovery, its principles and adequacy of these to the related ones in the chapter had been analyzed that turns on the national economic Order, describing the formal procedure for concession of the benefit of the Judicial Recovery and the principles in existing them. The forms of intervention of the State in the private economy were not disrespected, relating its direct and indirect performance as half of preservation of interests writings in the constitutional scope as public interest and preservation of the National economic Order. The regulating agencies as of direct state intervention were half not disrespected of the study for the relevance of the subject. It is revised national bibliography with incursions in French, Portuguese and North American comparative jurisprudence. One contributes in the aspect of the paper of the Judiciary Power in the protection of the companies in crisis and the social and economic impacts, over all in relation to the rights of the worked ones, credit and enterprise

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This work presents simulation results of an identification platform compatible with the INPE Brazilian Data Collection System, modeled with SystemC-AMS. SystemC-AMS that is a library of C++ classes dedicated to the simulation of heterogeneous systems, offering a powerful resource to describe models in digital, analog and RF domains, as well as mechanical and optic. The designed model was divided in four parts. The first block takes into account the satellite s orbit, necessary to correctly model the propagation channel, including Doppler effect, attenuation and thermal noise. The identification block detects the satellite presence. It is composed by low noise amplifier, band pass filter, power detector and logic comparator. The controller block is responsible for enabling the RF transmitter when the presence of the satellite is detected. The controller was modeled as a Petri net, due to the asynchronous nature of the system. The fourth block is the RF transmitter unit, which performs the modulation of the information in BPSK ±60o. This block is composed by oscillator, mixer, adder and amplifier. The whole system was simulated simultaneously. The results are being used to specify system components and to elaborate testbenchs for design verification

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This work proposes a new methodology to verify those analog circuits, providing an automated tools to help the verifiers to have a more truthful result. This work presents the development of new methodology for analog circuits verification. The main goal is to provide a more automated verification process to certify analog circuits functional behavior. The proposed methodology is based on the golden model technique. A verification environment based on this methodology was built and results of a study case based on the validation of an operational amplifier design are offered as a confirmation of its effectiveness. The results had shown that the verification process was more truthful because of the automation provided by the tool developed

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Cells of Mikania glomerata, Cephaelis ipecacuanha and Maytenus aquifolia were co-cultured in a two-phase system using filter paper as a solid support. The species were co-cultured in all possible paired combinations. Interaction between Mikania and Maytenus cells resulted in increased biomass production of Maytenus cells, but the friedelin content was reduced. Co-cultivation of Cephaelis and Mikania cells enhanced coumarin content, but inhibited the growth of Mikania cells. However, yield of emetine as well as Cephaelis biomass accumulation were positively stimulated by the co-cultivation. Results indicate a possible occurrence of allelopathy in such a system.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The addition of soybean oil and Tween 80 was evaluated with the objective of increasing the production of botryosphaeran, an exopolysaccharide (EPS) of the (1 -> 3 ;1 -> 6)-beta-D-glucan type produced by the fungus Botowsphaeria rhodina MAMB-05. Factorial design and analysis by response surface methodology was developed to select the main factors that would affect and enhance EPS production. The optimized culture conditions were: 40g l(-1) glucose with 10ml l(-1) soybean oil, and 4.5 ml l(-1) Tween 80, during 72h cultivation at 28 degrees C (180 rpm) and initial pH 5.7. The predicted result for botryosphaeran production was 8.22 +/- 1.36 g l(-1), and compared with the experimental value of 7.74 +/- 0.13 g l(-1) . Partial characterization of the botryosphaeran produced under the optimized conditions showed one type of polysaccharide with P-glycosidic linkages containing glucose as monosaccharide. (c) 2007 Elsevier Ltd. All rights reserved.