Novas fases amorfas de carbono produzidas por irradiação iônica de filmes de C/sub 60/, [alfa]-C e [alfa]-C:H

Neste trabalho estuda-se a formação de novas fases de carbono amorfo através da irradiação iônica de filmes de fulereno, a-C e a-C:H polimérico. Os efeitos da irradiação iônica na modificação das propriedades ópticas e mecânicas dos filmes de carbono irradiados são analisados de forma correlacionada com as alterações estruturais a nivel atômico. O estudo envolve tanto a análise dos danos induzidos no fulereno pela irradiação iônica a baixas fluências, correspondendo a baixas densidades de energia depositada, quanto a investigação das propriedades físico-químicas das fases amorfas obtidas após irradiações dos filmes de fulereno, a-C e a-C:H com altas densidades de energia depositada. As propriedades ópticas, mecânicas e estruturais das amostras são analisadas através de técnicas de espectroscopia Raman e infravermelho, espectrofotometria UV-VIS-NIR, microscopias ópticas e de força atômica, nanoindentação e técnicas de análise por feixe de íons, tais como retroespalhamento Rutherford e análises por reação nuclear. As irradiações produzem profundas modificações nas amostras de fulereno, a-C e a-C:H, e por conseqüência significativas alterações em suas propriedades ópticas e mecânicas. Após máximas fluências de irradiação fases amorfas rígidas (com dureza de 14 e 17 GPa) e com baixos gaps ópticos (0,2 e 0,5 eV) são formadas. Estas estruturas não usuais correspondem a arranjos atômicos com 90 a 100% de estados sp2. Em geral fases sp2 são planares e apresentam baixa dureza, como predito pelo modelo de “cluster”. Entretanto, os resultados experimentais mostram que as propriedades elásticas das novas fases formadas são alcançadas através da criação de uma estrutura sp2 tridimensional. A indução de altas distorções angulares, através da irradiação iônica, possibilita a formação de anéis de carbono não hexagonais, tais como pentágonos e heptágonos, permitindo assim a curvatura da estrutura. Utilizando um modelo de contagem de vínculos é feita uma análise comparativa entre a topologia (estrutura geométrica) de ligações C-sp2 e as propriedades nanomecânicas. São comparados os efeitos de estruturas sp2 planares e tridimensionais (aleatórias) no processo de contagem de vínculos e, conseqüentemente, nas propriedades elásticas de cada sistema. Os resultados mostram que as boas propriedades mecânicas das novas fases de carbono formadas seguem as predições do modelo de vínculos para uma rede atômica sp2 tridimensional. A formação de uma fase amorfa dura e 100% sp2 representa uma importante conquista na procura de novas estruturas rígidas de carbono. A síntese da estrutura desordenada sp2 tridimensional e vinculada aqui apresentada é bastante incomum na literatura. O presente trabalho mostra que o processo de não-equilíbrio de deposição de energia durante a irradiação iônica permite a formação de distorções angulares nas ligações sp2-C, possibilitando a criação de estruturas grafíticas tridimensionais.

Processos produtivos e trabalho-educação: a incorporação do caboclo catarinense na indústria madeireira

The object theme of the present study is a population of caboclos that absorbed as manual workers in the saw-mills which were mounted in the highland region of Santa Catarina since 1950. The abundance of araucaria (native kind of pine) the opening of markets, and the corroboration of other industrial exploration conditions encouraged a great crowd of small en.- trepreneurs, coming basically from the state of Rio Grande do Sul, to migrate and settle down, building up a lot of saw-mills near rich forests and fields. The saw-mills started aprosperous production of timber sawn in planks. The process of industriali zation was so intensive, the destruction of pine woods soviolent that, in less than three decades, the forests ran out of tree reserves. The caboclos, absorbed as manual workers in production of timber, lived traditionally in an system of subsistense, either from the cultivation of pine the economic their land (planter caboclo) or as labourers in cattle-growing farms (farm hand caboclos). Nevertheless, the 'advantages' that were offered them by the new-comer entrepreneurs (a salary paid in money, a new house in a village, and other favours) helped the great majority of caboclos to abandon their traditional work and enlist as "workmen" in saw-mills. The new job, besides being a novelty, was an opportunity for a change in status. Subsequently, the running out of forests of araucaria and the resultant progressive shut-down of saw-mills caused the crowd of workmen to be out of imployment and to form to form a migratory flood toward the most important town of the region, Lages. The town of Lages, however, having made of the timber i ts main economic support wi thout the implantation of an alternative industry, was unable to offer the migrantssufficient 'work places'. In this way, the 'marginal crowd' began to settle down in the suburbs of the city. This study, in the context of the object theme, analyses two main questions related to the reality 'WOlLQ' and to the economic exploitation forms: ~) the relations of production in the economic regime of subsistence and in the capitalist regime of industrial production with the consequent 'positions' of the workman in the productive processj ~~) the deriving educative effects of the productive process, either in the economic regime of subsistence, or in the capitalist industrial regime. The two questions are theoretically debated andconfro~ ted with the proposed reality, giving origin to conclusions that, in a general formulation, can be summarized as follows: a) the caboclos of the highland region of Santa Catari na, when under an economic regime of subsistence, held in fee the productive processj there was a social division of the work and aclimate of freedom which made possible the development of knowledge from their life and work experience, the production of most of their tools, and the making of necessary manufactures adapted to their own surrounding ditionsi -- - --- other con- ------ b) however, these same caboclos, when absorbed by the capitalist industrial process of production - tipified by the work in saw-mills - lost the control of the productive processj this was caused by the technologic division of the work, since each man began to perform a dull and repeti tive action, directed by the speed of the 'major-saw' j man resigned form his skill and inventive power and surrendered to an executive authority which turned him into a 'collective worker'j the new productive process, besides rnaking each rnan a copy of a pattern, put the caboclos in a situation in which the daily work experiencedidn't add anything in terrns of autogenesis of knowledgei and even the environrnental educative rneans were reduced to new forrns of adaptation to the productive process, relegating rnan's inventive power to inertia.

O campo em revista: agrarismo e modernismo no Estado do Rio de Janeiro nos anos de 1920

O presente trabalho pesquisa como o campo foi interpretado nos anos de 1920 pelos intelectuais fluminenses. Por meio da analise de três revistas – Illustração Fluminense (1921-1924), A Agricultura Fluminense: revista da Sociedade de Agricultura e Indústrias Ruraes (1926) e A Fazenda Fluminense (1929-1930) – busca-se compreender como o rural foi uma via alternativa para a modernização do Estado do Rio de Janeiro. A revista foi um gênero de imprensa símbolo da modernidade que produzia novas sensibilidades e comportamentos em uma época de transformações. A economia fluminense encontrava-se em crise desde o final do século XIX fazendo com que o Estado passasse a ter um papel secundário na política nacional republicana. O projeto das revistas agrícolas analisadas desejavam reconstruir essa identidade fluminense ao propor um campo modernizado, com novas técnicas de cultivo, com políticas de diversificação agrícola, com investimentos na educação rural e com pequenas propriedades. O rural, tantas vezes ligado ao “atraso”, integrou as propostas modernistas fluminenses discutidas no início do século XX.

Crowdfunding no Brasil: uma análise sobre as motivações de quem participa

Este trabalho procurou investigar as motivações para a participação de apoiadores no modelo de recompensa de crowdfunding no Brasil, sob a luz dos aspectos encontrados na pesquisa americana de Gerber e Hui (2014). Como a participação nesse modelo é voluntária, entendeu- se ser importante compreender os motivos que levam pessoas a apoiarem projetos. Acredita- se que este trabalho tenha atingido o que foi por ele proposto, deixando contribuições em diversos sentidos. A fim de aprofundar o entendimento desse novo fenômeno social, apresentou-se uma pesquisa qualitativa fundamentada em um estudo de caso múltiplo, em que os apoiadores eram a unidade de análise, nas três maiores plataformas de crowdfunding do Brasil: Queremos, Catarse e Benfeitoria. E, como fonte de informações para esta metodologia, optou-se pelo método qualitativo de entrevistas em profundidade com os elementos da unidade de análise. Foram realizadas 11 entrevistas com apoiadores, sendo 06 homens e 05 mulheres. O trabalho também teve o objetivo de conhecer melhor o cenário nacional desse mercado, a partir de entrevistas em profundidade com os fundadores das plataformas e um heavy user (mais de 140 projetos apoiados) do modelo. Após a consolidação e análise dos dados obtidos, verificou-se a presença das motivações encontradas nos estudos de Gerber (GERBER e HUI, 2014), porém com algumas ressalvas quanto a motivação “Fazer parte de uma comunidade”, explicitada a seguir. A pesquisa qualitativa refinou substancialmente a compreensão do que motiva apoiadores a participar de crowdfunding, incluindo aspectos importantes que devem ser levados em consideração quanto a práticas do mercado. Ao final, as conclusões e implicações deste estudo foram detalhadamente apresentadas.

Crowdfunding : de modismo a novo instrumento financeiro

Essa dissertação tem como objetivo avaliar a atratividade para o pequeno investidor brasileiro, do ponto de vista financeiro, de uma nova forma de investimento, definida a partir de características do modelo brasileiro de crowdfunding e das ferramentas de investimento tradicionais, a ser chamada de crowdinvesting. A partir do entendimento detalhado do modelo de crowdfunding existente no país e da identificação e mapeamento das características dos instrumentos de investimento tradicionais, esse estudo busca definir como deve funcionar a nova forma de investimento proposta, e analisar se, em comparação com as ferramentas tradicionais, em termos de risco e retorno, o crowdinvesting seria competitivo no mercado brasileiro.

Qualificação jurídica das plataformas de crowdinvesting no Brasil: um estudo de caso da plataforma online da Broota Brasil

Crowdinvesting consiste na captação de recursos financeiros por empreendedores, por meio de uma plataforma online na internet, em que os investidores recebem em troca de seus aportes financeiros uma participação na empresa nascente investida. Trata-se de uma modalidade de financiamento peculiar, uma vez que usualmente realiza a oferta pública de valores mobiliários. O objetivo deste trabalho é identificar elementos para se pensar na qualificação jurídica da plataforma online de crowdinvesting, a partir da descrição de suas atividades realizadas no âmbito da oferta pública de valores mobiliários. Para tanto, foi escolhida a plataforma online da Broota Brasil como objeto único de análise, pois é a empresa pioneira na atividade. Identificar os elementos que propiciam uma reflexão acerca da qualificação jurídica que a plataforma online de crowdinvesting é importante, pois permite a (i) reflexão acerca do seu possível tratamento jurídico; e (ii) verificar se há segurança jurídica nas atividades cursadas no âmbito da plataforma online. Para nortear o presente trabalho, foram eleitas duas hipóteses de pesquisa, considerando que a plataforma online consiste em um ambiente virtual que disponibiliza espaço para a realização de ofertas públicas de valores mobiliários, sendo reputada como (i) mercado de balcão organizado; ou (ii) mercado de balcão não organizado. Assim, é realizada a descrição das atividades da plataforma online da Broota Brasil no âmbito da realização de oferta pública de valores mobiliários. Após, com base na legislação e doutrina específica, foi efetuada a descrição das características que conceituam juridicamente as referidas hipóteses. Em seguida, foram identificadas se tais características estavam presentes nas atividades desenvolvidas pela plataforma online da Broota Brasil. Por fim, não sendo reveladas tais características, sugere-se uma agenda de pesquisa apontando as possíveis qualificações jurídicas da plataforma online, em razão de sua aproximação de empreendedores e investidores no âmbito do negócio jurídico de compra e venda de oferta pública de valores mobiliários.

Use of Fibres Obtained from the Cashew (Anacardium ocidentale, L) and Guava (Psidium guayava) Fruits for Enrichment of Food Products

OLIVEIRA, E. L. et al. Use of Fibres obtained from the Cashew (Anacardium ocidentale, L) and Guava (Psidium guayava) Fruits for Enrichment of Food Products. Brazilian Archives of Biology and Technology, Curitiba, PR, v. 48, p. 143-150, 2005.

Processamento e análise de imagens na caracterização da superfície do titânio submetido a um ensaio de cultura de células

This work aims to develop a methodology for analysis of images using overlapping, which assists in identification of microstructural features in areas of titanium, which may be associated with its biological response. That way, surfaces of titanium heat treated for 08 (eight) different ways have been subjected to a test culture of cells. It was a relationship between the grain, texture and shape of grains of surface of titanium (attacked) trying to relate to the process of proliferation and adhesion. We used an open source software for cell counting adhered to the surface of titanium. The juxtaposition of images before and after cell culture was obtained with the aid of micro-hardness of impressions made on the surface of samples. From this image where there is overlap, it is possible to study a possible relationship between cell growth with microstructural characteristics of the surface of titanium. This methodology was efficient to describe a set of procedures that are useful in the analysis of surfaces of titanium subjected to a culture of cells

Ecologia do fitoplâncton impactado por cultivo de tilápia do Nilo, oreochromis niloticus, em tanques-rede no açude Ministro João Alves, Parelhas, Rio Grande do Norte

The dams are limnic ecosystems of great importance for its multiple uses, among them, water supply for the public and to culture of artisanal fish are most relevant. The aim of the present study is to evaluate the physical-chemical characteristics and the phytoplankton community in two chosen sites (Point 1 littoral zone of point source; Point 2 pelagic zone of non-point source) of the Minister João Alves dam, which is also known as Boqueirão de Parelhas/RN. This represents the spatial distribution of the phytoplankton species in order to understand any possible alterations of the water quality and the phytoplankton composition in relation to the water quality originating from the impact of the tilapia, Oreochromis niloticus, culture. The study period also encompasses temporal variations exhibited in two seasons of an annual cycle, one during the dry season (Oct, Nov and Dec of 2008 and Jan of 2009), and the other rainy season (Mar, Apr, May and June of 2008) to extend the observation. The physicalchemical parameters, such as pH, temperature, electrical conductivity, concentration of dissolved oxygen were measured in situ and the values of the inorganic nutrients (nitrate, ammonium and orto-phosfato) and chlorophyll in the laboratory. The quali-quantitative analyses of the phytoplankton had been carried through sedimentation technique and the enumeration of the random of 400 cells, colonies and filaments counted using Sedgwick-Rafter counting chamber. The results of pH varied widely from the acidic to alkaline range with the minimum of 5.8 (± 0.8) and the maximum of 9.2 (± 0.7-0.8), at point 1 and 2. The dissolved oxygen content was higher in the rainy period than that in the dry period. The maximum electrical conductivity was of 1409 μScm-1 in point 1 and 431 minim of μScm-1, in point 2. There was a considerable alteration in the levels of inorganic nutrients such as nitrate-nitrogen, ammoniacal nitrogen and orthophosphate during the two cycles of study period. Phytoplankton assemblages presented a picture of alternate dominance among species Cyanobacteria, Bacillariophyceae and Chlorophyceae. The trophic state index diagnosed to the category of mesotrophic, which is based on the values of chlorophyll, total phosphorus and Secchi-disc measurements. The wind driven turbulence of the water column and the fresh inflow of water (flushing and dilution) during rainy season acted as constraint and did-not allow an exaggerated growth of the species of cyanobacteria. On the basis of the present we conclude that the culture of tilapias in cage-culture fails to produce pollution load that could compromise the quality of the water of the dam, probably be due to small dimension of the culture in relation to the size, volume of the water and the reservoir capacity support its own environment

Estudo comparativo da variação temporal da comunidade fitoplanctônica do açude Cruzeta inserido no bioma caatinga, Rio Grande do Norte

The Cruzeta impoundment, situated in the city of Cruzeta, hinterland of the state of the Rio Grande do Norte state has significant importance to the municipality as it represents the only source of supplying water to the region. It was hypothesized that the regional consequence of the global warming and the warming of surface water could substantially contribute the significant growth of the aquatic macrophytes in the years 2008-2009. The growth of these vegetation believed to be improved the degree of water transparency and as a consequence of the improved growth of phytoplankton species and chlorophyll biomass. At the same time the aquatic macrophyte could interact and compete potentially for the dissolved inorganic nutrients resources and the phytoplankton community. This study presents a comparison of years 2004-2005 when it did not have the expressive presence of the aquatic macrophyte community or restricted to the littoral region. In contrast, the years 2008-2009 showed a significant growth of the aquatic macrophyte in the Cruzeta/RN impoundments. The present study is an attempt to elucidate the significant presence of the aquatic macrophyte, Eichhornia crassipes, Ceratophyllum submersum, Nymphea sp and Pistia sp, and its interference on the ecology of phytoplankton. The samplings had been carried out from September of 2008 to April of 2009 and consistently between 10:00 h and 12:00 h with the aid of Van Dorn bottle and the plankton net of mesh size 20 Qm. The collections were made in three depths ie., surface, mid-column and bottom. The Physical-Chemical parameters such as pH, temperature, electrical conductivity and dissolved oxygen had been analyzed in situ. The samples for analysis of nutrients and chlorophyll were kept under refrigeration for posterior analysis in the laboratory. Phytoplankton samples were preserved in Lugol-iodine and kept for sedimentation for quali-quantitative analysis of phytoplankton. Enumeration of cells, colonies and filaments was done with the aid of Sedgwick-Rafter counting chamber and expressed as numbers/ml. Chlorophyll a was analyzed as a functional component of phytoplankton biomass and extracted with cold 90% acetone. The results indicate that the chlorophyll concentration varied between 5,65-8,08 Qg.L-1 for the dry period and 5,09-6,23 Qg.L-1 for the rainy period and showed considerable reduction when compared to the values to the 2004-2005 study period. The temperature was always presented higher in relation to the 2004-2005 study. Phytoplankton species showed a relative abundance of the Cyanophyceae for both the period of dry and rainy. The predominance species are filamentous Leptolymbya geophila Borzi (Planctolyngbya sp), Anabaena plankctônica Brunnthaler, Oscillatória limosa Ag. and Cylindrospermopsis raciborskii (Wolosz). The concentration of the nutrients such as nitrate and orto-phosfato had always presented higher values during the rainy period and the ammoniacal nitrogen retained moderate values in the dry period and a slight increase in rainy season. The main conclusions are the reduction of the concentration of chlorophyll, diversity of phytoplankton, and the increase in temperature and transparency of the water during the period of the study

Análise fractal da vasculatura arteriolar e venular da retina em pessoas sem doença ocular

Although it has been suggested that retinal vasculature is a diffusion-limited aggregation (DLA) fractal, no study has been dedicated to standardizing its fractal analysis . The aims of this project was to standardize a method to estimate the fractal dimensions of retinal vasculature and to characterize their normal values; to determine if this estimation is dependent on skeletization and on segmentation and calculation methods; to assess the suitability of the DLA model and to determine the usefulness of log-log graphs in characterizing vasculature fractality . To achieve these aims, the information, mass-radius and box counting dimensions of 20 eyes vasculatures were compared when the vessels were manually or computationally segmented; the fractal dimensions of the vasculatures of 60 eyes of healthy volunteers were compared with those of 40 DLA models and the log-log graphs obtained were compared with those of known fractals and those of non-fractals. The main results were: the fractal dimensions of vascular trees were dependent on segmentation methods and dimension calculation methods, but there was no difference between manual segmentation and scale-space, multithreshold and wavelet computational methods; the means of the information and box dimensions for arteriolar trees were 1.29. against 1.34 and 1.35 for the venular trees; the dimension for the DLA models were higher than that for vessels; the log-log graphs were straight, but with varying local slopes, both for vascular trees and for fractals and non-fractals. This results leads to the following conclusions: the estimation of the fractal dimensions for retinal vasculature is dependent on its skeletization and on the segmentation and calculation methods; log-log graphs are not suitable as a fractality test; the means of the information and box counting dimensions for the normal eyes were 1.47 and 1.43, respectively, and the DLA model with optic disc seeding is not sufficient for retinal vascularization modeling

Estimating abundance and spatial distribution patterns of the bubble crab Dotilla fenestrata (Crustacea : Brachyura)

The bubble crab Dotilla fenestrata forms very dense populations on the sand flats of the eastern coast of Inhaca Island, Mozambique, making it an interesting biological model to examine spatial distribution patterns and test the relative efficiency of common sampling methods. Due to its apparent ecological importance within the sandy intertidal community, understanding the factors ruling the dynamics of Dotilla populations is also a key issue. In this study, different techniques of estimating crab density are described, and the trends of spatial distribution of the different population categories are shown. The studied populations are arranged in discrete patches located at the well-drained crests of nearly parallel mega sand ripples. For a given sample size, there was an obvious gain in precision by using a stratified random sampling technique, considering discrete patches as strata, compared to the simple random design. Density average and variance differed considerably among patches since juveniles and ovigerous females were found clumped, with higher densities at the lower and upper shore levels, respectively. Burrow counting was found to be an adequate method for large-scale sampling, although consistently underestimating actual crab density by nearly half. Regression analyses suggested that crabs smaller than 2.9 mm carapace width tend to be undetected in visual burrow counts. A visual survey of sampling plots over several patches of a large Dotilla population showed that crab density varied in an interesting oscillating pattern, apparently following the topography of the sand flat. Patches extending to the lower shore contained higher densities than those mostly covering the higher shore. Within-patch density variability also pointed to the same trend, but the density increment towards the lowest shore level varied greatly among the patches compared.