Langevin equations for competitive growth models

Langevin equations for several competitive growth models in one dimension are derived. For models with crossover from random deposition (RD) to some correlated deposition (CD) dynamics, with small probability p of CD, the surface tension \nu and the nonlinear coefficient \lambda of the associated equations have linear dependence on p due solely to this random choice. However, they also depend on the regularized step functions present in the analytical representations of the CD, whose expansion coefficients scale with p according to the divergence of local height differences when p->0. The superposition of those scaling factors gives \nu ~ p^2 for random deposition with surface relaxation (RDSR) as the CD, and \nu ~ p, \lambda ~ p^{3/2} for ballistic deposition (BD) as the CD, in agreement with simulation and other scaling approaches. For bidisperse ballistic deposition (BBD), the same scaling of RD-BD model is found. The Langevin equation for the model with competing RDSR and BD, with probability p for the latter, is also constructed. It shows linear p-dependence of \lambda, while the quadratic dependence observed in previous simulations is explained by an additional crossover before the asymptotic regime. The results highlight the relevance of scaling of the coefficients of step function expansions in systems with steep surfaces, which is responsible for noninteger exponents in some p-dependent stochastic equations, and the importance of the physical correspondence of aggregation rules and equation coefficients.Comment: 8 pages with 1 figure include

Macroeducação e permacultura urbana: Análise do impacto da macroeducação em unidades familiares e a eficácia da adoção de tecnologia alternativa.

Resumo: A crescente urbanização tem acarretado grandes problemas com relação aos recursos hídricos disponíveis. A permacultura se apresenta como ferramenta socioambiental, e juntamente com os conceitos da bioconstrução servem de motivação à adoção de práticas sustentáveis numa relação de equilíbrio entre homem e natureza. A educação ambiental se propõe de forma pedagógica a estimular a formação de comunidades sustentáveis, por onde, segundo os conceitos da Macro-educação, é possível aplicar de uma forma eficaz e objetiva, o planejamento estratégico, estimulando a adoção de tecnologias sustentáveis e um uso mais consciente dos recursos naturais. Este trabalho visa sensibilizar a comunidade do bairro Jardim Santana no município de Campinas a adotar novos hábitos e atitudes ecologicamente corretos, e estimular a adoção de tecnologias alternativas como kit de captação de águas pluviais com garrafas pet, que terá como aplicação alternativa a irrigação da horta urbana, de uma unidade familiar, com o intuito de reduzir o consumo da água tratada disponibilizada pelas entidades locais. Abstract: Increasing urbanization has caused major problems in relation to the available water resources. The permaculture presents itself as a socio-environmental tool, and with the concepts of bio construction, is used as motivation for adoption of sustainable practices balancing man and nature. Environmental education is proposed as pedagogical to stimulate the sustainable communities generation, where, according to the concepts of Macro-education, it is possible to apply in an effective way and objective, the strategic planning, encouraging the adoption of sustainable Technologies and a conscious usage of the natural resources. This work aims to involve the community in Santana neighborhood in Campinas, to adopt new friendly environmental habits and attitudes and encourage adoption of alternative technologies to implement a kit of rainwater reception with pet bottles. This will be applied in irrigation of urban plantation at residential units, with the aim of reducing the cost of the treated water made available by the local authorities

ViZon: visualizador de zoneamentos agroecológicos

A grande dificuldade dos mapeamentos e dos zoneamentos agroecológicos está na disponibilização de seu conteúdo de modo que as pessoas responsáveis pelas tomadas de decisão possam rapidamente pesquisar e recuperar informações que sirvam de suporte ao seu trabalho. Desta forma, o objetivo deste trabalho é descrever a metodologia para o desenvolvimento de um software para visualizar, pesquisar e exportar os mapas e os dados dos zoneamentos agroecológicos produzidos pela Embrapa Solos. Por meio da linguagem C# codificada na plataforma SharpDevelop e utilizando bibliotecas ArcReaderControl foi possível desenvolver uma arquitetura flexível e atualizavel para agregar o grande volume e variedade de informações geradas pelos zoneamentos agroecológicos. Como resultado obteve-se um software (ViZon) que congrega mapas, tabelas, textos, fotos e links numa plataforma amigável ao usuário leigo e com poderosas ferramentas ao usuário especializado. Na utilização com o Zoneamento Agroecológico do Estado de Alagoas (ZAAL) foi possível concluir que o software atende aos requisitos definidos pela equipe de pesquisa. Também é possível concluir que o ViZon, com sua plataforma flexível e atualizável, pode ser utilizado numa vasta quantidade de projetos de mapeamentos e zoneamentos agroecológico

Radiolysis of ammonia-containing ices by energetic, heavy and highly charged ions inside dense astrophysical environments

Deeply inside dense molecular clouds and protostellar disks, the interstellar ices are protected from stellar energetic UV photons. However, X-rays and energetic cosmic rays can penetrate inside these regions triggering chemical reactions, molecular dissociation and evaporation processes. We present experimental studies on the interaction of heavy, highly charged and energetic ions (46 MeV Ni^13+) with ammonia-containing ices in an attempt to simulate the physical chemistry induced by heavy ion cosmic rays inside dense astrophysical environments. The measurements were performed inside a high vacuum chamber coupled to the heavy ion accelerator GANIL (Grand Accelerateur National d'Ions Lourds) in Caen, France.\textit{In-situ} analysis is performed by a Fourier transform infrared spectrometer (FTIR) at different fluences. The averaged values for the dissociation cross section of water, ammonia and carbon monoxide due to heavy cosmic ray ion analogs are ~2x10^{-13}, 1.4x10^{-13} and 1.9x10^{-13} cm$^2$, respectively. In the presence of a typical heavy cosmic ray field, the estimated half life for the studied species is 2-3x10^6 years. The ice compaction (micropore collapse) due to heavy cosmic rays seems to be at least 3 orders of magnitude higher than the one promoted by (0.8 MeV) protons . In the case of the irradiated H2O:NH3:CO ice, the infrared spectrum at room temperature reveals five bands that were tentatively assigned to vibration modes of the zwitterionic glycine (+NH3CH2COO-).Comment: Accepted to be published in Astronomy and Astrophysics; Number of pages: 12; Number of Figures: 7; Number of Tables: