1000 resultados para Taxonomia vegetal : Leguminosae : Teses : Brasil


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O destino das águas pluviais nas cidades é um problema frequente no Brasil. Ausência de infraestrutura adequada ou manutenção delas pode causar alagamentos, erosões, entre outros, tanto em grandes centros urbanos como em pequenas cidades. Neste tema, desenvolveu-se uma pesquisa no município de Terra Rica, região Noroeste do Paraná, Brasil. As rochas e os solos da área são provenientes da Formação Caiuá, susceptíveis à ocorrência de erosões, que ocorrem de forma natural, quando na presença de precipitações elevadas e da ausência de cobertura vegetal, agravando-se com a ação antrópica. As águas que se precipitam sobre o perímetro urbano do município em questão são drenadas artificialmente, através de tubulações para o córrego Trajano, onde deu origem ao que hoje é uma feição erosiva de grande porte, voçoroca. Esta pesquisa, com base em fundamentação teórica e campo, teve como objetivo levantar o histórico da ocorrência desta voçoroca que está localizada perpendicular à rodovia PR-557. Os levantamentos realizados constataram que esta feição tem um histórico de obras de contenção já realizadas e que o problema ainda não foi totalmente resolvido. Os resultados obtidos contribuíram para orientar as medidas corretivas, mitigadoras e preventivas que podem ser adotadas pelos órgãos responsáveis do bem estar social.

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A partir da apresentação do contexto, história e evolução da agroecologia no Brasil, seguida do levantamento dos aportes e contribuições teóricas que a influenciaram e das estratégias para seu desenvolvimento, os autores trazem algumas conclusões e reflexões, tais como a que de que a agroecologia depende da força da interação entre os movimentos sociais, redes científicas e construção de políticas públicas.

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As Áreas de Preservação Permanente foram instituídas para preservar o meio ambiente, devendo estar cobertas pela vegetação natural. Esta cobertura vegetal minimiza os impactos negativos ao meio ambiente, como processos erosivos, lixiviação dos solos, assoreamento de cursos d’água, contribuindo assim, para a regularização do fluxo hídrico. De outra forma, com a ausência dessa cobertura vegetal ocorre-se aceleradamente a degradação ambiental.

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Fruta típica de clima temperado, a cultura da maçã (Malus domestica Borkh) aumentou significativamente a sua produtividade nas últimas duas décadas, permitindo o Brasil sair da condição de importador para exportador da fruta. Devido sua grande representatividade na fruticultura brasileira, a cadeia produtiva da maçã é uma das atividades que mais recebe investimento em tecnologia e qualidade no país. O frio é o principal agente responsável pela saída da dormência das plantas caducifólias, 16 sendo que estas, quando cultivadas em regiões com insuficiência de frio hibernal, apresentam desuniformidade na brotação e longo período de floração, afetando drasticamente a produção. Quando a superação, efetivamente, da dormência das plantas de clima temperado não é satisfeita pela insuficiente acumulação de frio, é necessário o uso de práticas culturais que possam viabilizar o cultivo dessas fruteiras. Dentre as mais utilizadas para a superação da dormência em macieiras, está o uso de indutores de brotação. Porém, os produtos comerciais a base de cianamida hidrogenada, que são utilizados para induzir a brotação de macieiras apresentam elevada toxidade. Frente à necessidade de se dispor de produtos com menor toxicidade e agressão ao meio ambiente, o desenvolvimento de novos compostos que possuam tais características, aliada à eficiência na indução da brotação é almejada (HAWERROTH, 2009). Nesse sentido, objetivou-se com esse trabalho avaliar a utilização de diferentes combinações de Bluprins® 28 com nitrato de cálcio e óleo mineral para indução de brotação de macieiras 'Fuji Kiku' em região produtora de maçã no sul do Brasil.

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Prosopis rubriflora and Prosopis ruscifolia are important species in the Chaquenian regions of Brazil. Because of the restriction and frequency of their physiognomy, they are excellent models for conservation genetics studies. The use of microsatellite markers (Simple Sequence Repeats, SSRs) has become increasingly important in recent years and has proven to be a powerful tool for both ecological and molecular studies. In this study, we present the development and characterization of 10 new markers for P. rubriflora and 13 new markers for P. ruscifolia. The genotyping was performed using 40 P. rubriflora samples and 48 P. ruscifolia samples from the Chaquenian remnants in Brazil. The polymorphism information content (PIC) of the P. rubriflora markers ranged from 0.073 to 0.791, and no null alleles or deviation from Hardy-Weinberg equilibrium (HW) were detected. The PIC values for the P. ruscifolia markers ranged from 0.289 to 0.883, but a departure from HW and null alleles were detected for certain loci; however, this departure may have resulted from anthropic activities, such as the presence of livestock, which is very common in the remnant areas. In this study, we describe novel SSR polymorphic markers that may be helpful in future genetic studies of P. rubriflora and P. ruscifolia.

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Aeschynomene falcata is an important forage species; however, because of low seed production, it is underutilized as forage species. Aeschynomene is a polyphyletic genus with a challenging taxonomic position. Two subgenera have been proposed, and it is suggested that Aeschynomene can be split in 2 genera. Thus, new markers, such as microsatellite sequences, are desirable for improving breeding programs for A. falcata. Based on transferability and in situ localization, these microsatellite sequences can be applied as chromosome markers in the genus Aeschynomene and closely related genera. Here, we report the first microsatellite library developed for this genus; 11 microsatellites were characterized, with observed and expected heterozygosities ranging from 0.0000 to 0.7143 and from 0.1287 to 0.8360, respectively. Polymorphic information content varied from 0.1167 to 0.7786. The departure from Hardy-Weinberg equilibrium may have resulted from frequent autogamy, which is characteristic of A. falcata. Of the 11 microsatellites, 9 loci were cross-amplified in A. brevipes and A. paniculata and 7 in Dalbergia nigra and Machaerium vestitum. Five of these 7 cross-amplified microsatellites were applied as probes during the in situ hybridization assay and 2 showed clear signals on A. falcata chromosomes, ensuring their viability as chromosome markers.

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Multidrug-resistant microbial infections represent an exponentially growing problem affecting communities worldwide. Photodynamic therapy is a promising treatment based on the combination of light, oxygen, and a photosensitizer that leads to reactive oxygen species production, such as superoxide (type I mechanism) and singlet oxygen (type II mechanism) that cause massive oxidative damage and consequently the host cell death. Indigofera genus has gained considerable interest due its mutagenic, cytotoxic, and genotoxic activity. Therefore, this study was undertaken to investigate the effect of crude extracts, alkaloidal fraction, and isolated substance derived from Indigofera truxillensis in photodynamic antimicrobial chemotherapy on the viability of bacteria and yeast and evaluation of mechanisms involved. Our results showed that all samples resulted in microbial photoactivation in subinhibitory concentration, with indigo alkaloid presenting a predominant photodynamic action through type I mechanism. The use of CaCl2 and MgCl2 as cell permeabilizing additives also increased gram-negative bacteria susceptibility to indigo.

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This study focus on the reconfiguration of educational management in Argentina, Brazil, Chile and Mexico, which was promoted by the new logic of social regulation and the new role attributed to the State, considering each country's own historicity. So, the cultural factors that interfere on the dynamics of the 90' school reform are analyzed. Aspects that show the homogeneity or heterogeneity of these reforms in the region, as well as local specificities that block out the concretization of the reform are underlined. It is shown that the historicity that characterizes the educational reform has taken, in each country, a form that can be called, in Mexico, conservative rupture; in Chile, conservative continuity; in Brazil, conservative renovation; and, in Argentina, interrupted rupture. Some conclusions about the impact of educational reform in the selected countries are recuperated through the analysis of 186 academic texts on the subject.

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This article analyses the emergence and development of social policies for children and adolescents attendance that are in line with the development process of the Brazilian social protection system, focusing on some of the main representations attributed to childhood, according to the historical and political periods. It seeks to present the notion of childhood instituted under the constitution of the Brazilian welfare state, in such a way as to place it within the broader context of the historical and political transformations that involved the emergence and consolidation of the social policies directed towards children and adolescents in Brazil in the 20th century and the beginning of the 21st.

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The purpose of this article is to develop some ideas that may contribute to the debate about the secondary education in Brazil, giving emphasis to the conditions existing in the educational institutions, the ongoing educational policies and the challenges posed by the social, economic and political reality of the country. It is also discussed the political, social and economic importance of the expansion and the compulsory character of secondary education as well as the school's culture dimension, in its relationship to the so-called knowledge society. Finally, the role of secondary education for the youth and the new demands it poses for teachers are presented, among some others aspects.

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This article takes the concepts of biopower and governmentality as the starting point for an analysis of certain recent Brazilian government documents about the introduction of Philosophy as a subject in secondary school. In the 1980s, this argument centered on Philosophy's so-called criticism and its potential for preparing citizens for a democratic society, was used by the movements aimed to restore democracy in Brazil. This argument appears to have been assimilated by the Brazilian government, because it is stated in the Guidelines and Bases of Education Law, secondary school students should demonstrate knowledge of philosophy necessary for the exercise of citizenship. The argument also appears in documents such as the PCN and PCN+ (National Curricular Parameters) and OCEM (Curriculum Guidelines for Secondary School) in their chapters on Philosophy. These documents are examined here in the light of governmentality, making explicit how Philosophy is equipped to train young people according to what is understood as a modern democratic society.

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Chemical research in Brazil has grown significantly in the past 20 years, largely thanks to the Brazilian S&T Development Program of the federal government (PADCT). However, the newly achieved levels of highly qualified manpower and research infra-structure require new research organization frameworks to make science, technology and innovation really useful and meaningful for the citizens. The current requirements for creating viable networks of academic and industry researchers are presented and discussed as well as some structural and procedural bottlenecks that have to be eliminated, to achieve maximum high-quality science, technology and relevant innovation output.

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Chemometric activities in Brazil are described according to three phases: before the existence of microcomputers in the 1970s, through the initial stages of microcomputer use in the 1980s and during the years of extensive microcomputer applications of the ´90s and into this century. Pioneering activities in both the university and industry are emphasized. Active research areas in chemometrics are cited including experimental design, pattern recognition and classification, curve resolution for complex systems and multivariate calibration. New trends in chemometrics, especially higher order methods for treating data, are emphasized.

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Quimica Nova and the Journal of the Brazilian Chemical Society are two examples of successful initiatives taken by the Brazilian Chemical Society (SBQ - Sociedade Brasileira de Química), and may serve as models for the scientific societies of developing countries. Pillars of the SBQ, these two periodicals are undeniable demonstrations that idealism, utopia and dignity are the essential ingredients for transforming dreams into reality. Few believed that the Brazilian chemical community would one day have, as it does today, two scientific research periodicals indexed in the principal international data banks.