Non-Equilibrium Modeling of the Fe XVII 3C/3D ratio for an Intense X-ray Free Electron Laser

We present a review of two methods used to model recent LCLS experimental results for the 3C/3D line intensity ratio of Fe XVII (Bernitt et al. 2012), the time-dependent collisional-radiative method and the density-matrix approach. These are described and applied to a two-level atomic system excited by an X-ray free electron laser. A range of pulse parameters is explored and the effects on the predicted Fe XVII 3C and 3D line intensity ratio are calculated. In order to investigate the behavior of the predicted line intensity ratio, a particular pair of A-values for the 3C and 3D transitions was chosen (2.22 $\times$ 10$^{13}$ s$^{-1}$ and 6.02 $\times$ 10$^{12}$ s$^{-1}$ for the 3C and 3D, respectively), but our conclusions are independent of the precise values. We also reaffirm the conclusions from Oreshkina et al.(2014, 2015): the non-linear effects in the density matrix are important and the reduction in the Fe XVII 3C/3D line intensity ratio is sensitive to the laser pulse parameters, namely pulse duration, pulse intensity, and laser bandwidth. It is also shown that for both models the lowering of the 3C/3D line intensity ratio below the expected time-independent oscillator strength ratio has a significant contribution due to the emission from the plasma after the laser pulse has left the plasma volume. Laser intensities above $\sim 1\times 10^{12}$ W/cm$^{2}$ are required for a reduction in the 3C/3D line intensity ratio below the expected time independent oscillator strength ratio

Scaling Limit and Critical Exponents for Two-Dimensional Bootstrap Percolation

Consider a cellular automaton with state space $\{0,1 \}^{{\mathbb Z}^2}$ where the initial configuration $\omega_0$ is chosen according to a Bernoulli product measure, 1's are stable, and 0's become 1's if they are surrounded by at least three neighboring 1's. In this paper we show that the configuration $\omega_n$ at time n converges exponentially fast to a final configuration $\bar\omega$, and that the limiting measure corresponding to $\bar\omega$ is in the universality class of Bernoulli (independent) percolation. More precisely, assuming the existence of the critical exponents $\beta$, $\eta$, $\nu$ and $\gamma$, and of the continuum scaling limit of crossing probabilities for independent site percolation on the close-packed version of ${\mathbb Z}^2$ (i.e., for independent $*$-percolation on ${\mathbb Z}^2$), we prove that the bootstrapped percolation model has the same scaling limit and critical exponents. This type of bootstrap percolation can be seen as a paradigm for a class of cellular automata whose evolution is given, at each time step, by a monotonic and nonessential enhancement.Comment: 15 page

Resinose do coqueiro: como identificar essa doença.

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Acima dos confrontos sobre os transgênicos: uma experiência piloto de consulta pública.

RESUMO: A tecnologia do DNA recombinante abriu, juntamente com um horizonte ilimitado de possibilidades de inovações, polêmicas que não podem ser ignoradas ou resolvidas por meio de uma difusão linear de informações. Ações multidisciplinares e multi-institucionais têm sido implementadas, com sucesso, em diversos países, para estabelecer novas formas de comunicação entre peritos e leigos. Isso permite identificar possíveis restrições e benefícios nas trajetórias tecnológicas, e assim entender e negociar eventuais conflitos. No Brasil, esse tipo de abordagem não tem recebido atenção significativa. A metodologia Problem Formulation and Options Assessment (PFOA), articulada no contexto do projeto internacional Genetically Modified Organisms - Environmental Risk Assessment (GMO-ERA), e sintonizada com as novas tendências de envolvimento dos diversos setores de interesse (stakeholders) ligados a uma tecnologia, propõe integrar na análise de risco as perspectivas ambiental, social, econômica e ética. A equipe de implementação de uma experiência piloto do PFOA foi formada pelo grupo do GMOERA - ligado ao Projeto Rede de Biossegurança (BioSeg), da Empresa Brasileira de Pesquisa Agropecuária (Embrapa), pelo Instituto de Pesquisa em Riscos e Sustentabilidade, da Universidade Federal de Santa Catarina (Iris-UFSC), e pelo Centro de Gestão de Estudos Estratégicos do Ministério da Ciência e Tecnologia (CGEE/MCT). O caso utilizado como modelo foi o feijão geneticamente modificado resistente ao mosaico-dourado, que vem sendo desenvolvido pela Embrapa. O piloto, financiado pelo CGEE/MCT, contou com a participação de diversos stakeholders. Dentre as conclusões, recomenda-se o uso de sistemas de informação não unidirecionados, mais transparentes e abertos, baseados em uma ciência rigorosa, para subsidiar as instâncias científicas e políticas nas tomadas de decisão. abstract: Recombinant DNA technology, together with an unlimited horizon of possibilities of innovation, triggered a discussion, among stakeholders, that cannot be ignored or solved through a linear difusion of information. Multidisciplinary and multi-institutional actions are being successfully adopted in several countries to establish new communication strategies between specialists and stakeholders. These strategies allow the identification of possible constraints and benefits of a technology during its development and, consequently, understanding and negotiation of conflicts. In Brazil this approach is not being used yet. The Problem Formulation and Options Assessment (PFOA) methodology was proposed by the Genetically Modified Organisms - Environmental Risk Assessment (GMO-ERA) project, aligned with the new trend of involving stakeholders in the risk assessment of a new technology. PFOA integrates the environmental, social, economic and ethical perspectives into the risk assessment of a technology. PFOA's pilot experience was conducted by a group formed by the GMO-ERA team associated with the Biosafety Network (BioSeg) project of the Brazilian Agricultural Research Corporation (Embrapa), by the Institute of Research in Risk and Sustainability from the Federal University of Santa Catarina (Iris-UFSC) and by the Center for Strategic Management and Studies in Science, Technology and Innovation of the Ministry of Science and Technology (CGEE/ MCT). The case study was a genetically modified bean resistant to the golden mosaic disease, which is being developed by Embrapa. This pilot was funded by CGEE/MCT and gathered representatives of several stakeholders. It could be concluded that the use of non-directed, transparent, open and science-based communication approaches is of great value for scientific and political decision making instances

Side Effects of Human Drug Use: An Overview of the Consequences of Eels’ Exposure to Cocaine

The widespread use of drugs is a global problem which affects not only humans but also the environment around them, as research is showing the presence of these substances in different environmental matrices, like air, water, and soil. Above all, due to the remarkable pharmacological properties of drugs, it is discovered that organisms accidentally exposed to them, as aquatic organisms, undergo behavioral and physiological changes that can compromise their health, survival, and reproduction ability. In addition to this, we must consider the ability of some drugs to accumulate within these organisms, thus entering the food chain, and the possible interactions that drugs in water can establish with each other and with other possible pollutants, making the final effects on exposed organisms unpredictable. This article is an overview of the effects of one of these drugs, cocaine, one of the drugs commonly found in the aquatic environment, on European eel, an endangered species and known biomonitor of aquatic contaminatio

Thermal phase diagrams of columnar liquid crystals

In order to understand the possible sequence of transitions from the disordered columnar phase to the helical phase in hexa(hexylthio)triphenylene (HHTT), we study a three-dimensional planar model with octupolar interactions inscribed on a triangular lattice of columns. We obtain thermal phase diagrams using a mean-field approximation and Monte Carlo simulations. These two approaches give similar results, namely, in the quasi one-dimensional regime, as the temperature is lowered, the columns order with a linear polarization, whereas helical phases develop at lower temperatures. The helicity patterns of the helical phases are determined by the exact nature of the frustration in the system, itself related to the octupolar nature of the molecules.Comment: 12 pages, 9 figures, ReVTe

Padrão de emergência de adultos do bicudo do algodoeiro, Anthonomus grandis, ao longo da safra e entressafra na região Centro-Oeste.

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