Crossovers from parity conserving to directed percolation universality

The crossover behavior of various models exhibiting phase transition to absorbing phase with parity conserving class has been investigated by numerical simulations and cluster mean-field method. In case of models exhibiting Z_2 symmetric absorbing phases (the NEKIMCA and Grassberger's A stochastic cellular automaton) the introduction of an external symmetry breaking field causes a crossover to kink parity conserving models characterized by dynamical scaling of the directed percolation (DP) and the crossover exponent: 1/\phi ~ 0.53(2). In case an even offspringed branching and annihilating random walk model (dual to NEKIMCA) the introduction of spontaneous particle decay destroys the parity conservation and results in a crossover to the DP class characterized by the crossover exponent: 1/\phi\simeq 0.205(5). The two different kinds of crossover operators can't be mapped onto each other and the resulting models show a diversity within the DP universality class in one dimension. These 'sub-classes' differ in cluster scaling exponents.Comment: 6 pages, 6 figures, accepted version in PR

Coleta de sementes florestais na Caatinga.

Seleção de árvores matrizes; Seleção de áreas de coleta de sementes; Planejamento da coleta; Método de coleta; Equipamentos para a coleta; Legislação para a coleta de sementes.bitstream/item/79736/1/INT104.pd

Beneficiamento de sementes florestais da Caatinga.

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As sementes da Caatinga são...: um levantamento das características das sementes da Caatinga.

O presente trabalho teve por objetivo realizar uma busca ampla sobre a expressão ?As sementes da caatinga são? e encontrar padrões característicos em estudos já realizados. A partir dos resultados da busca pode-se concluir que as sementes da Caatinga são produzidas durante todo o ano, mas a maioria é dispersada no final da estação seca. As sementes da Caatinga apresentam características morfofisiológicas de acordo com os locais onde são produzidas. Algumas sementes da Caatinga apresentam dormência tegumentar, no entanto, é raro encontrar dormência fisiológica. A maioria das sementes da Caatinga são apresentam tolerância a estresses abióticos, embora algumas espécies características deste ecossistema são sensíveis a algumas condições ambientais extremas. A comercialização das sementes da Caatinga ainda é incipiente. As sementes da Caatinga felizmente estão sendo estudadas em várias instituições do Nordeste, do Brasil e do mundo.Edição das Palestras do V Workshop de Tecnologia e Fisiologia de Sementes e Mudas, Petrolina, dez. 2014

Germinação de sementes de pimenta-rosa (Schinus terebinthifolius raddi) submetidas a diferentes temperaturas.

O presente trabalho tem como objetivo, avaliar o comportamento germinativo de sementes de pimenta-rosa quando submetidas a diferentes temperaturas. As sementes utilizadas foram coletadas no mês de setembro de 2009 de uma população existente próximo à Universidade de Brasília, Brasilia-DF. A semeadura foi feita separadamente em caixas tipo gerbox sob papel mata-borrão umedecido com 15mL de água, posteriormente as caixas foram incubadas em uma BOD sob diferentes temperaturas (20, 25, 30, 25/30°C) durante 15 dias onde foi avaliado diariamente a porcentagem de germinação, ao final do experimento foram calculados, o tempo médio de germinação, velocidade de germinação, indice de velocidade de germinação (IVG)

Teor de água sobre a germinação de sementes de aroeira-do-sertão.

O objetivo deste trabalho é avaliar o efeito do teor de água sobre a germinação de sementes de Aroeira-do-sertão.Edição dos Anais do 1 Simpósio da Rede de Recursos Genéticos Vegetais do Nordeste, Cruz das Almas, nov. 2013

Teor de água sobre a germinação de sementes de angico.

O objetivo deste trabalho é avaliar o efeito do teor de água sobre a germinação de sementes de angico.Edição dos Anais do 1 Simpósio da Rede de Recursos Genéticos Vegetais do Nordeste, Cruz das Almas, nov. 2013

A supercritical series analysis for the generalized contact process with diffusion

We study a model that generalizes the CP with diffusion. An additional transition is included in the model so that at a particular point of its phase diagram a crossover from the directed percolation to the compact directed percolation class will happen. We are particularly interested in the effect of diffusion on the properties of the crossover between the universality classes. To address this point, we develop a supercritical series expansion for the ultimate survival probability and analyse this series using d-log Pad\'e and partial differential approximants. We also obtain approximate solutions in the one- and two-site dynamical mean-field approximations. We find evidences that, at variance to what happens in mean-field approximations, the crossover exponent remains close to $\phi=2$ even for quite high diffusion rates, and therefore the critical line in the neighborhood of the multicritical point apparently does not reproduce the mean-field result (which leads to $\phi=0$) as the diffusion rate grows without bound

Quantification of Leishmania infantum DNA in females, eggs and larvae of Rhipicephalus sanguineus

<p/> <p>Background</p> <p><it>Leishmania infantum </it>is a widespread parasite that affects dogs and humans worldwide. It is transmitted primarily by phlebotomine sand flies, but recently there has been much discussion on the role of the brown dog tick, <it>Rhipicephalus sanguineus</it>, as a potential vector for this protozoan. Recent laboratory and field investigations have contributed to this hypothesis, but a proof of the vector capacity of <it>R. sanguineus </it>has yet to be provided. Following a recent study suggesting that <it>L. infantum </it>passes transovarially from the female tick to her progeny the current study provides new evidence of the transovarial transmission of <it>L. infantum </it>in <it>R. sanguineus</it>.</p> <p>Methods</p> <p>Engorged females of <it>R. sanguineus </it>were collected from the environment in a dog shelter of southern Italy, where canine leishmaniosis is endemic. In the laboratory, 97 females that successfully laid eggs, their eggs and the originated larvae were subjected to DNA extraction and then tested by a TaqMan-based real time PCR targeting a fragment of the kinetoplast DNA (kDNA) of <it>L. infantum</it>.</p> <p>Results and conclusions</p> <p><it>L. infantum </it>kDNA was detected in engorged females, their eggs and originating larvae, with a parasite load ranging from 1.8 × 10^-4to 10.0 × 10⁰. Certainly, the current study provides further evidence on the passage of <it>L. infantum </it>from <it>R. sanguineus </it>females to their offspring. The observation of promastigote forms in larvae is necessary to definitively confirm this hypothesis, which would raise interesting questions about the possible role of ticks in the maintenance of <it>L. infantum </it>infection among dogs in certain areas.</p

Bosonic Casimir effect in an aether-like Lorentz-violating scenario with higher order derivatives

In this paper we investigate the bosonic Casimir effect in a Lorentz-violating symmetry scenario. The theoretical model adopted consists of a real massive scalar quantum field confined in a region between two large parallel plates, having its dynamics governed by a modified Klein-Gordon equation that presents a Lorentz symmetry breaking term. In this context we admit that the quantum field obeys specific boundary conditions on the plates. The Lorentz-violating symmetry is implemented by the presence of an arbitrary constant space-like vector in a CPT-even aether-like approach, considering a direct coupling between this vector with the derivative of the field in higher order. The modification on the Klein-Gordon equation produces important corrections on the Casimir energy and pressure. Thus, we show that these corrections strongly depend on the order of the higher derivative term and the specific direction of the constant vector, as well as the boundary conditions considered.Comment: 21 pages, 5 figure