Mass hierarchy, mass gap and corrections to Newton's law on thick branes with Poincare symmetry

We consider a scalar thick brane configuration arising in a 5D theory of gravity coupled to a self-interacting scalar field in a Riemannian manifold. We start from known classical solutions of the corresponding field equations and elaborate on the physics of the transverse traceless modes of linear fluctuations of the classical background, which obey a Schroedinger-like equation. We further consider two special cases in which this equation can be solved analytically for any massive mode with m^2>0, in contrast with numerical approaches, allowing us to study in closed form the massive spectrum of Kaluza-Klein (KK) excitations and to compute the corrections to Newton's law in the thin brane limit. In the first case we consider a solution with a mass gap in the spectrum of KK fluctuations with two bound states - the massless 4D graviton free of tachyonic instabilities and a massive KK excitation - as well as a tower of continuous massive KK modes which obey a Legendre equation. The mass gap is defined by the inverse of the brane thickness, allowing us to get rid of the potentially dangerous multiplicity of arbitrarily light KK modes. It is shown that due to this lucky circumstance, the solution of the mass hierarchy problem is much simpler and transparent than in the (thin) Randall-Sundrum (RS) two-brane configuration. In the second case we present a smooth version of the RS model with a single massless bound state, which accounts for the 4D graviton, and a sector of continuous fluctuation modes with no mass gap, which obey a confluent Heun equation in the Ince limit. (The latter seems to have physical applications for the first time within braneworld models). For this solution the mass hierarchy problem is solved as in the Lykken-Randall model and the model is completely free of naked singularities.Comment: 25 pages in latex, no figures, content changed, corrections to Newton's law included for smooth version of RS model and an author adde

Harmful Elements in Estuarine and Coastal Systems

Estuaries and coastal zones are dynamic transitional systems which provide many economic and ecological benefits to humans, but also are an ideal habitat for other organisms as well. These areas are becoming contaminated by various anthropogenic activities due to a quick economic growth and urbanization. This chapter explores the sources, chemical speciation, sediment accumulation and removal mechanisms of the harmful elements in estuarine and coastal seawaters. It also describes the effects of toxic elements on aquatic flora and fauna. Finally, the toxic element pollution of the Venice Lagoon, a transitional water body located in the northeastern part of Italy, is discussed as a case study, by presenting the procedures adopted to measure the extent of the pollution, the impacts on organisms and the restoration activities

Synthesis, structure and applications of amorphous diamond

The relation was investigated between the compressive stress, the substrate temperature and the microstructure of amorphous carbon films deposited from the plasma stream of a cathodic vacuum arc with a curved magnetic filter. A pressure-temperature phase diagram is presented in which the results of a number of depositions at various substrate bias levels and temperatures are plotted. The microstructure of each film was determined by electron energy loss spectroscopy and electron diffraction

SYNTHESIS, STRUCTURE AND APPLICATIONS OF AMORPHOUS DIAMOND

The relation was investigated between the compressive stress, the substrate temperature and the microstructure of amorphous carbon films deposited from the plasma stream of a cathodic vacuum arc with a curved magnetic filter. A pressure-temperature phase diagram is presented in which the results of a number of depositions at various substrate bias levels and temperatures are plotted. The microstructure of each film was determined by electron energy loss spectroscopy and electron diffraction

Influência do sistema de condução do tomateiro sobre a incidência de doenças e insetos-praga Influence of the training systems of tomato plants on the incidence of diseases and insect-pests

Avaliou-se o efeito dos métodos de tutoramento e de condução de plantas de tomate sobre a severidade de doenças foliares e sobre a incidência de pragas em frutos em diferentes cultivares. Dois experimentos foram realizados em 2004/2005 e 2005/2006 em Caçador, SC. Os tratamentos consistiram da combinação de duas cultivares (Carmen e Débora Max, em 2004/2005, e Nemo Netta e San Vito, em 2005/2006); quatro métodos de tutoramento (cruzado, 'mexicano', vertical com bambu e vertical com fitilho) e dois métodos de condução de plantas (com uma e duas hastes por planta mantendo o mesmo número de hastes por área) em parcelas sub-subdivididas. Foram avaliadas as severidades de requeima, pinta-preta e mancha bacteriana nas folhas e a porcentagem de frutos com danos causados por doenças fisiológicas ou fitopatológicas e por brocas. Os métodos de tutoramento vertical proporcionaram menor severidade de requeima, pinta-preta e mancha bacteriana nas folhas e ataque de brocas nos frutos, em relação ao método de tutoramento cruzado. A severidade de doenças foliares e porcentagem de frutos com ataque de brocas não diferiram entre métodos de condução de plantas.<br>The effect of different methods of staking and training tomato plants was investigated to determine the severity of leaf damage and the incidence of pests in fruits of different cultivars. Two experiments were carried out in 2004/2005 and 2005/2006, in Caçador, Santa Catarina State, Brazil. The treatments consisted of the combination of two cultivars, Carmen and Débora Max, in 2004/2005, and Nemo Netta and San Vito, in 2005/2006; four staking methods, crossed fence, 'Mexican', vertical staking with bamboo and vertical staking with polypropylene cord; and two training methods, one and two stems per plant keeping the same number of stems per area. Severities of late blight, early blight and bacterial spot in leaves and the percentage of fruits with physiological and phytopathological diseases and with insect damages were evaluated. All vertical staking methods provided smaller severity of late blight, early blight and bacterial spot in leaves and attack of insects than crossed fence method. The severity of leaf diseases and percentage of fruits with insect damages did not differ among plant training methods

Genetic resources of vegetable crops: a survey in the Brazilian germplasm collections pictured through papers published in the journals of the Brazilian Society for Horticultural Science Recursos genéticos de hortaliças: as atividades nas coleções brasileiras de germoplasma retratadas nas publicações da Associação Brasileira de Horticultura

The research on plant genetic resources is essential for the conservation of genetic diversity and accessions' divergence studies, as a basis for plant breeding. Aiming to know the state of art in this subject, a historical survey was carried out in Revista de Olericultura and in Horticultura Brasileira, from 1961 to 2006, searching for papers dealing with vegetable crops genetic resources. In each of the papers, the species studied, first author institution, publication year, applied software, number of accessions and descriptors, and the multivariate techniques used were registered. Based on these characteristics, papers were grouped using multivariate analysis. Sixty-one papers dealt somehow with genetic resources in the time covered by the survey, from which 91.8% were published after 1990 (60.7% from 2001 to 2005). The use of multivariate analysis was reported in 57.3% of the papers, with an average of 2.3 and maximum of 6 multivariate procedures per paper. The Tocher Method, reported in 34% of the papers, was the most frequently used multivariate analysis. Twenty-five species were studied. Capsicum was the most frequently studied genus, either considering number of papers (seven) or accessions (664). Research institutions located in the Southeast region concentrated the highest number of papers. UFV (Federal University of Viçosa), UENF (North Fluminense State University Darcy Ribeiro), Embrapa Vegetables, and UNESP (São Paulo State University) Campus of Jaboticabal responded for 45% of the papers. There was an improvement in the adequacy of the statistical techniques used along time, due mainly to the development of free-access software. The software Genes was the most frequently reported in the papers surveyed. Nevertheless, almost 50% of the authors did not mention the software used for data analysis. Quantitative morphoagronomic and evaluation descriptors were the most often used. The multivariate analysis allowed grouping the papers in nine clusters.<br>A pesquisa com recursos genéticos vegetais é essencial tanto para a conservação da diversidade genética, quanto para o estudo da divergência entre acessos, base para programas de melhoramento. Com objetivo de conhecer o estado-da-arte nesse tema, foram identificados os trabalhos relacionados a recursos genéticos de hortaliças publicados na " Revista de Olericultura" e " Horticultura Brasileira" , de 1961 a 2006. Foram anotadas as espécie(s) estudada(s), a instituição de origem do primeiro autor, o ano de publicação, os softwares utilizados, o número de acessos, o número de descritores e o número de técnicas multivariadas aplicadas em cada artigo. Com base nessas caraterísticas, os artigos foram agrupados utilizando análise multivariada. No período pesquisado, 61 artigos trataram, sob algum aspecto, de recursos genéticos. Desses, 91,8% foram publicados a partir de 1990, com concentração de 2001 a 2005 (60,7%), com 57,3% deles utilizando pelo menos uma técnica multivariada, com média de 2,3 e máximo de seis técnicas por artigo. O método de agrupamento de Tocher foi o mais utilizado, relatado em 34% dos artigos. Os artigos cobriram 25 espécies. Dentre elas, Capsicum foi o gênero mais pesquisado, tanto em relação ao número de artigos (sete), quanto em número de acessos estudados (664). As instituições de pesquisa da região Sudeste concentraram o maior número de artigos. Se somadas, UFV, UENF, Embrapa Hortaliças e UNESP Campus de Jaboticabal foram responsáveis por 45% dos trabalhos publicados no tema. Houve um aprimoramento das técnicas estatísticas utilizadas na análise dos dados, sobretudo devido ao desenvolvimento e uso de softwares de fácil compreensão. O programa GENES foi o mais referenciado. Entretanto, quase a metade dos autores não citou o programa estatístico utilizado para a análise dos dados. Os descritores de caracterização morfoagronômica quantitativos e de avaliação foram os mais estudados. A análise multivariada permitiu classificar os artigos em nove grupos