Tratamentos de fibras de carnaúba [copernicia prunífera (miller) h. e. moore] para o desenvolvimento de compósito biodegradável com matriz de polihidroxibutirato

The use of raw materials from renewable sources for production of materials has been the subject of several studies and researches, because of its potential to substitute petrochemical-based materials. The addition of natural fibers to polymers represents an alternative in the partial or total replacement of glass fibers in composites. In this work, carnauba leaf fibers were used in the production of biodegradable composites with polyhydroxybutyrate (PHB) matrix. To improve the interfacial properties fiber / matrix were studied four chemical treatments to the fibers..The effect of the different chemical treatments on the morphological, physical, chemical and mechanical properties of the fibers and composites were investigated by scanning electron microscopy (SEM), infrared spectroscopy, X-ray diffraction, tensile and flexural tests, dynamic mechanical analysis (DMA), thermogravimetry (TGA) and diferential scanning calorimetry (DSC). The results of tensile tests indicated an increase in tensile strength of the composites after the chemical treatment of the fibers, with best results for the hydrogen peroxide treated fibers, even though the tensile strength of fibers was slightly reduced. This suggests a better interaction fiber/matrix which was also observed by SEM fractographs. The glass transition temperature (Tg) was reduced for all composites compared to the pure polymer which can be attributed to the absorption of solvents, moisture and other low molecular weight molecules by the fibers

Instituições prevalecentes, tradição e persistência no extrativismo da cera de carnaúba em Limoeiro do Norte -CE

A presente pesquisa visa entender os fatores que explicam a manutenção dos aspectos artesanais no extrativismo da cera de carnaúba em Limoeiro do Norte. Justificamos a exploração desse tema pelo fascínio do autor pelo tema e por ser esse recurso ainda uma importante fonte de renda para produtores e trabalhadores rurais no respectivo município. Objetivamos nessa pesquisa identificar as razões pelas quais a atividade mantém seu padrão tecnológico intacto. Primeiro objetivamos uma descrição do processo produtivo da cera, tanto no passado, quanto no presente, comparando estes momentos e ressaltando o caráter artesanal da atividade, além de analisar a importância atual da atividade para aqueles que ainda lidam com esse tipo de produção, bem como procuramos revelar estrutura histórica e institucional que permeia a lógica e as escolhas destes produtores, a qual pode explicar a preservação destes aspectos artesanais. Utilizando o referencial teórico do institucionalismo, explicamos que a preservação destes aspectos artesanais, ocorre em virtude da prevalência de determinadas instituições, como a memória coletiva cultivada entre os rendeiros idosos e resistentes, a concentração fundiária, responsável pelo arrendamento e também as restritas possibilidades de investimento e poupança no processo produtivo, em face do baixo nível de renda de produtores, os quais com um produto pouco competitivo no mercado, pouco podem fazer para inovar tecnologicamente.

Caracterização do óleo de carnaúba para uso como biolubrificante

Lubricant is responsible for reducing the wear on the friction protect the metal against oxidation, corrosion and dissipates excess heat, making it essential for the balance of a mechanical system, consequently prolonging the useful life of such a system. The origin of lubricating oils is usually mineral being extracted from the petroleum. But the search for a new source of production of lubricants and fuels it is necessary to meet future demands and reduce the possible environmental damage. For this reason, looking alternative means to produce certain products derived from petroleum, such as biodiesel, for example. Returning to the realm of lubricants, also one realizes this need for new raw materials for their production. Vegetable oil is a renewable resource and biodegradable, and its use entails advantages in environmental, social and economic. The development of this project aims to characterize the carnauba oil as a lubricant plant, or biolubricant. To analyze the oil carnauba tests as checking density, flash point, fire point, viscosity, viscosity, acid number, pH, copper corrosion, thermal conductivity and thermal resistivity were developed. In addition, for conducting the wear on the friction and the gradient of the system temperature, the analysis equipment is designed for wear on the friction. Based on these results, it is observed that the oil carnauba show good correlation to its application as biolubricant

Viabilidade de uso de um fogão solar para cocção de alimentos com parábola refletora fabricada em compósito que utiliza fibras de Carnaúba e resina Ortoftálica

Presents a composite formed by orthophthalic resin and fiber loading of carnauba straw. The fibers were first dried in direct sun exposure and subsequently ground into fodder for the reduction in size. Various formulations of the composite were preliminarily tested by choosing the one presenting the best processability in applying the mold. The composite produced is used for the manufacture of a parabolic surface subsequently coated with mirror segments, flexible plastic, for reflecting the solar rays incident on it. The reflective parable represents the main element of the solar cooker that works with the concentration of sunlight and has dimensions of 1.14 m in diameter and area of 1.0 m². Manufacturing processes and assembly of solar cooker concentration produced are presented. The results of tests for cooking and baking various foods, including rice, pasta, beans, cake, cassava, shrimp, beef, breaded demonstrating the competitiveness of solar cooker studied with other stoves already manufactured and tested in Brazil are presented and in the world. It was also demonstrated the feasibility of the proposed composite for Prototypes manufacture of solar and other structures that do not require great efforts resistance

Extração de ferro da cera de carnaúba utilizando sistemas microemulsionados

The constant search for biodegradable materials for applications in several fields shows that carnauba wax can be a viable alternative in the manufacturing of biolubricants. Carnauba wax is the unique among the natural waxes to have a combination of properties of great importance. In previous studies it was verified the presence of metals in wax composition that can harm the oxidative stability of lubricants. Considering these factors, it was decided to develop a research to evaluate iron removal from carnauba wax, using microemulsion systems (Me) and perform the optimization of parameters, such as: extraction pH, temperature, extraction time, among others. Iron concentration was determined by atomic absorption and, to perform this analysis, sample digestion in microwave oven was used, showing that this process was very efficient. It was performed some analysis in order to characterize the wax sample, such as: attenuated total reflectance infrared spectroscopy (ATR-IR), thermogravimetry (TG), differential scanning calorimetry (DSC), energy dispersive X-ray fluorescence (EDXRF), scanning electron microscopy (SEM) and melting point (FP). The microemulsion systems were composed by: coconut oil as surfactant, n-butanol as cosurfactant, kerosene and/or heptanes as oil phase, distilled water as water phase. The pH chosen for this study was 4.5 and the metal extraction was performed in finite experiments. To evaluate Me extraction it was performed a factorial design for systems with heptane and kerosene as oil phase, also investigating the influence of temperature time and wax/Me ratio, that showed an statistically significant answer for iron extraction at 95% confidence level. The best result was obtained at 60°C, 10 hours contact time and 1: 10 wax/Me ratio, in both systems with kerosene and heptanes as oil phase. The best extraction occurred with kerosene as oil phase, with 54% iron removal

Sitios geologicos e geomorfologicos dos municipios de Acari, Carnaúba dos Dantas e Currais Novos, região saridó do Rio Grande do Norte

Geological and Geomorphological Sites of the Towns of Acari, Carnaúba dos Dantas and Currais Novos, Seridó Region of the Rio Grande do Norte, northeastern Brazil, consist s of a study about geological, geomorphological, mineralogical, palaeontological and archaeological features of the study area, aiming the identification of sites that presents scientific, historical, cultural, economic and ecological excellent importance, and that they deserve to receive special protection for its maintenance for the gifts and future generations. It was developed according with methods adopted for the Brazilian Commitee of Geological and Paleontological Sites SIGEP/UNESCO and by Initiati ve of Sofia for the Preservation of the Mineral Diversity of the Planet, objectifying the description of the main sites, the its environmental problematic and proposal of protectionistic measures. Seven sites with features and typical structures had been identified that they deserve to be aim of protection. In the Acari town, three sites had been identified: geological -geomorphologicalarchaeological site Barra of the Carnaúba; geological-geomorphological site of the Gargalheiras; and geological-geomorphological site Bico of Arara. In Carnaúba of the Dantas, the geomorphological complex river of the Bojo that possesss canyons and deep throats, with rocky-arts registers of the three great rocky-arts traditions of northeast: Northeast Seridó Sub-tradition, Wasteland and Itaquatiara. In the Currais Novos town, 3 sites had been also identified: geomorphological site Canyon of the Apertados; geomorphological-archaeological-palaeontological complex of the Totoró; e, geologicalmineralogical site Brejuí. Because to the environmental problematic that it involves each one of the identified sites, it is proposed, as a guarantee of protection to these sites, its economic exploitation with the ecogeotouristic activity, that it aims at to the integration of the community in programs of environmental education and others, besides providing to the generation of job and income for the towns. Finally, a series of measures is suggested that they aim at to the efectivation of the activity and to the protection of the sites that they can be classified as natural heritage, in accordance with the denomination of UNESCO, in its program World Natural Heritage

Uso da palha de carnaúba em revestimento de dutos

In this work, the plant species Copernicia prunifera (Miller) H. E. Moore (carnauba), naturally occurring which prevails in the northeast region of Brazil was the subject of studies aiming its use as external coating of pipelines used in petroleum industry. The part of the plant worked were the leaves, also called straw, which were coated with resinous material. For this purpose, it was necessary to evaluate the effectiveness of the use of acrylic resins in the straw carnauba coating. The properties of the untreated carnauba straw and chemically treated with sodium hydroxide, hexane and carbon tetrachloride were investigated by ATRFTIR, SEM and thermal analysis. The first two techniques showed that treatment with solvents has caused major changes in the straw surface, while the thermal analysis indicated that the sodium hydroxide caused variations in thermal stability of straw constituents. Water absorption measurements showed that treatments have accelerated the absorption process and the reduction of contact angle values for treated samples with solvents indicated higher hidrophilicity of straw. The tensile tests showed lower values of elastic modulus and tensile strength for treated samples. Furthermore, coatings using pure commercial resins A and B as well as the formulations with clay were applied in straw and they were examined once again through thermal analysis, water absorption measurements, contact angle and mechanical tests. To analyze the effect of heat ageing, samples were subjected to tensile tests again in order to assess its resistance. The results showed that the resins/clay formulations increased thermal stability of straw, they promoted a good impermeabilization and caused significant decrease in the values of elastic modulus and tensile strength. Evaluating the ageing effect on the mechanical properties, it has been showed good recovery to the coated straw with the formulations A 60 and A 80% in modulus and tensile strength values and elongation at break values have remained very close. It is thus concluded that the carnauba straw can be used as a coating of pipelines with significant cost savings, since there is no need for pretreatment for its use and shows itself as a viable biotechnology alternative, contributing to the quality of coatings material and environment preservation.

Uso do pó da palha de carnaúba em compósitos de quitosana

In this work a biodegradable composite using the carnauba straw s powder as reinforcement on chitosan matrix polymeric were manufactured. Firstly, were carried out the chemistry characterization of the carnauba straw s powder before and after treatments with NaOH and hexane. Goering and Van Soest method (1970), flotation test, moisture absorption, FTIR, TG/DTG, DSC and SEM have also being carried out. Composites were developed with variations in granulometry and in powder concentrations. They were characterized by TG/DTG, SEM and mechanicals properties. The results of chemical composition showed that the carnauba straw s powder is composed of 41% of cellulose; 28,9% of hemicellulose and 14% of lignin.The flotation test have indicated that the chemical treatment with NaOH decreased the powder s hidrophilicity.The thermal analysis showed increased of thermal stability of material after treatments. The results of FTIR and SEM revealed the removal of soluble materials from the powder (hemicelluloses and lignin), the material became rougher and clean. The composites obtained showed that the mechanicals properties of the composites were decreased in respect at chitosan films, and the composites with the powder at 150 Mesh showed less variation in the modulus values. The speed test of 10 mm/min showed the better reproducibility of the results and is in agreement to the standard ASTM D638. The SEM analysis of fracture showed the low adhesion between the fiber/matrix. The increase of volume of powder in the composite caused a decrease in values of stress and strain for the samples with untreated powder and treated with hexane. The composite with 50% of the powder s treated in NaOH didn t have significant variation in the values of stress and strain as compared with the composites with 10% of the powder, showing that the increase in the volume of fiber didn t affect the stress and strain of the composite. Thereby, it is concluded that the manufacture of polymeric composites of chitosan using carnauba straw s powder can be done, without need for pre-treatment of reinforcement, become the couple of carnauba straw s powder-chitosan a good alternative for biodegradable composites

Tratamento superficial de argilas com cera de carnaúba e microemulsão de óleo de coco

Adsorption is a process that has become indispensable due to pollution caused by industrial activity. More economically viable adsorbents are being tested to replace the high cost of materials used. The clays can be used as adsorbents and are low cost materials, natural properties feasible for the application in the adsorption process, structural modifications are performed with ease promoting selective adsorption in these materials. The objective of this study was to synthesize and characterize adsorbents used in the adsorption of organic compounds. The adsorbents were characterized by the techniques of XRD, SEM, FTIR and TG. The results show that the studied materials have affinity to organic compounds and can be applied as adsorbents. The materials studied are viable and can be applied in the treatment of effluents contaminated in industrial scale.

Desenvolvimento e caracterização de biocompósito de látex (borracha natural) e fibra de carnaúba

The development of composite materials encompasses many different application areas. Among the composites, it is had, especially, the materials of organic origin, which have the greatest potential for biodegradability and so, have been bringing relevance and prominence in the contemporary setting of environmental preservation and sustainable development. Following this perspective of ecological appeal, it was developed a biocomposite material with natural inputs typically brazilian. This composite was made from latex (natural rubber) and carnauba fiber in different mass proportions. Formulations had varied by 5%, 10%, 15% and 20% of fiber in relation the matrix. This material has been designed aiming at application in thermal insulation systems, which requirethermal protection surfaces and/or reduction of thermal energy loss. Therefore, the composite was characterized by thermal conductivity testing, specific heat, thermal diffusivity and thermogravimetry. As has also been characterized for their physical-mechanical, by testing density, moisture content, tensile strength, hardness and scanning electron microscopy (SEM). The characterization of the material revealed that the composite presents a potential of thermal insulation higher than the natural rubber, that was used as reference. And the formulation at 15% fiber in relation the matrix showed the best performance. Thus, the composite material in question presents itself as a viable and effective alternative for new thermal insulation material design.

Desenvolvimento e caracterização de biocompósito de látex (borracha natural) e fibra de carnaúba

The development of composite materials encompasses many different application areas. Among the composites, it is had, especially, the materials of organic origin, which have the greatest potential for biodegradability and so, have been bringing relevance and prominence in the contemporary setting of environmental preservation and sustainable development. Following this perspective of ecological appeal, it was developed a biocomposite material with natural inputs typically brazilian. This composite was made from latex (natural rubber) and carnauba fiber in different mass proportions. Formulations had varied by 5%, 10%, 15% and 20% of fiber in relation the matrix. This material has been designed aiming at application in thermal insulation systems, which requirethermal protection surfaces and/or reduction of thermal energy loss. Therefore, the composite was characterized by thermal conductivity testing, specific heat, thermal diffusivity and thermogravimetry. As has also been characterized for their physical-mechanical, by testing density, moisture content, tensile strength, hardness and scanning electron microscopy (SEM). The characterization of the material revealed that the composite presents a potential of thermal insulation higher than the natural rubber, that was used as reference. And the formulation at 15% fiber in relation the matrix showed the best performance. Thus, the composite material in question presents itself as a viable and effective alternative for new thermal insulation material design.

Tratamentos de fibras de carnaúba [copernicia prunífera (miller) h. e. moore] para o desenvolvimento de compósito biodegradável com matriz de polihidroxibutirato

The use of raw materials from renewable sources for production of materials has been the subject of several studies and researches, because of its potential to substitute petrochemical-based materials. The addition of natural fibers to polymers represents an alternative in the partial or total replacement of glass fibers in composites. In this work, carnauba leaf fibers were used in the production of biodegradable composites with polyhydroxybutyrate (PHB) matrix. To improve the interfacial properties fiber / matrix were studied four chemical treatments to the fibers..The effect of the different chemical treatments on the morphological, physical, chemical and mechanical properties of the fibers and composites were investigated by scanning electron microscopy (SEM), infrared spectroscopy, X-ray diffraction, tensile and flexural tests, dynamic mechanical analysis (DMA), thermogravimetry (TGA) and diferential scanning calorimetry (DSC). The results of tensile tests indicated an increase in tensile strength of the composites after the chemical treatment of the fibers, with best results for the hydrogen peroxide treated fibers, even though the tensile strength of fibers was slightly reduced. This suggests a better interaction fiber/matrix which was also observed by SEM fractographs. The glass transition temperature (Tg) was reduced for all composites compared to the pure polymer which can be attributed to the absorption of solvents, moisture and other low molecular weight molecules by the fibers

Resumos...

Custo do controle químico da ferrugem asiática da soja na safra 2006/07; Estimativa do custo de produção de semente de soja no Triângulo Mineiro e Alto Paranaíba safra 2006/07; Programa de difusão de cultivares de soja desenvolvida pela Embrapa Soja, para os Estados do Paraná, de Santa Catarina, do Mato Grosso do Sul e de São Paulo - safra 06/07; Índices fisiológicos de cultivares de soja em diferentes épocas de semeadura no oeste da Bahia; Acúmulo de matéria seca e área foliar de cultivares de soja em diferentes épocas de semeadura no oeste da Bahia; Resistência à penetração, densidade e umidade de um latossolo vermelho distroférrico sob diferentes sistemas de produção; Monitoramento de insetos-pragas na cultura da soja, no Estado do Tocantins; Efeito de diferentes práticas de controle de pragas sobre a população de lagartas, percevejos e seus inimigos naturais, na cultura da soja; Avaliação de inseticidas e enxofre no controle de percevejo castanho e de corós, na cultura da soja; Diferentes inseticidas e doses no controle da lagarta falsa medideira (Pseudoplusia includens Walker, 1857), na cultura da soja; Eficiência de inseticidas/acaricidas no controle do ácaro verde, Mononychellus planki, na cultura da soja; Seletividade do inseticida flubendiamide e dos inseticidas spirotetramat & imidacloprid m mistura de pronto uso sobre artropodos predadores naturalmente encontrados no agroecossistema soja; Principais problemas fitossanitários detectados na cultura da soja no nordeste paraense - safra 2006/2007; Quais as causas da soja louca? Avaliação da reação de genótipos de soja ao nematóide das lesões radiculares; Avaliação da reação de espécies vegetais ao nematóide das lesões radiculares; Efeito do tratamento de sementes + aplicação foliar de fungicidas no manejo da ferrugem asiática da soja; Eficiência de fluquinconazole, via tratamento de sementes, no controle da ferrugem asiática da soja; Tratamento de sementes de soja com fluquinconazole associado à pulverização de fungicidas visando o controle da ferrugem asiática e da mancha parda; Aplicação aérea de tebuconazole + benzimidazol para o controle da ferrugem asiática da soja; Eficiência de triazóis nos ensaios em rede para controle da ferrugem asiática da soja (Phakopsora pachyrhizi); Eficiência de estrobilurinas, misturas de triazóis e estrobilurinas e triazóis e benzimidazóis nos ensaios em rede para controle da ferrugem asiática da soja (Phakopsora pachyrhizi); Resultados sumarizados dos ensaios em rede para controle da mela da soja (Rhizoctonia solani AG1); BRS Charrua RR: cultivar de soja indicada para o sul do Estado de Mato Grosso do Sul; ? BRS Pampa RR: cultivar de soja indicada para o sul do Estado de Mato Grosso do Sul; BRS 232: extensão de indicação para a região sul do Estado de Mato Grosso do Sul; BRS 243RR: extensão de indicação para a região sul do Estado de Mato Grosso do Sul; BRS 245RR: extensão de indicação para a região sul do Estado de Mato Grosso do Sul; BRS 246RR: extensão de indicação para a região sul do Estado de Mato Grosso do Sul; Recomendação da cultivar de soja CD 224 para os Estados do Paraná, São Paulo e região sul do Estado do Mato Grosso do Sul; Recomendação da cultivar de soja CD 225RR para o Estado do Paraná ; Recomendação da cultivar de soja CD 226RR para o Estado do Paraná e região sul do Estado do Mato Grosso do Sul; Recomendação da cultivar de soja CD 227 para os Estados de Goiás e Minas Gerais e região sul e norte do Estado do Mato Grosso; Extensão da cultivar de soja CD 219RR para o Estado da Bahia; Cultivar de soja BRSMG 810C; Cultivar de soja BRSMG 850GRR: indicação para o Estado de Goiás e Distrito Federal; Cultivar de soja BRSMG 750SRR: indicação para os estados de São Paulo, Goiás e Distrito Federal; Análise discriminante na caracterização de novos descritores em soja [Glycine max (L.) Merrill]; Influência do tamanho de semente na caracterização de descritores adicionais de soja; ? Estimativa de repetibilidade da avaliação de resistência ao oídio em genótipos de soja adaptados ao Estado de Goiás; Indicação da cultivar de soja BRSGO Graciosa para os Estados de Goiás e Distrito Federal; Reação de genótipos de soja à síndrome da morte súbita, causada pelo fungo Fusarium solani f. sp. Glicynes; Reação de genótipos de soja à ferrugem asiática, causada pelo fungo Phakopsora pachyrhizi Sydow; Indicação da cultivar de soja EMGOPA 302 RR,para o Estado de Goiás e Distrito Federal; Indicação da cultivar de soja emgopa 315 RR, para o Estado de Goiás e Distrito Federal; Indicação da cultivar de soja EMGOPA 316 RR, para o Estado de Goiás e Distrito Federal; GT - 8901: nova cultivar de soja para os Estados de Goiás e Distrito Federal; GT - 8901: nova cultivar de soja para as regiões norte e nordeste; Comportamento de cultivares de soja sob condições de várzea irrigada no sul do Estado do Tocantins, entressafra 2005; Extensão de indicação da cultivar BRS Barreiras para o Piauí, sul do Maranhão e norte de Tocantins; Cultivar de soja BRS 270RR: descrição, comportamento e indicação para cultivo; Cultivar de soja BRS 271RR: descrição, comportamento e indicação para cultivo; Extensão de indicação da cultivar BRS 252 para cultivo no cerrado de Roraima; Extensão de indicação da cultivar BRS Carnaúba para cultivo em cerrado de Roraima; Produtividade e qualidade de sementes de genótipos de soja hortaliça em cerrado de Roraima 2006/2007; Influência da adubação potássica e umidade do solo na produção da soja; Resposta da cultura de soja a diferentes níveis de adubação potássica em cobertura; Teores de potássio em amostras foliares de soja obtidos por digestão nitroperclórica e por extração com água; Nível crítico de manganês trocável no solo, para soja em latossolo vermelho de textura argilosa do Mato Grosso; Nível crítico de manganês trocável no solo, para a soja, em latossolo vermelho de textura argilosa do Maranhão; Nível crítico de manganês trocável no solo, para a soja em latos-solo vermelho amarelo de textura média do Maranhão; Aplicação foliar de soluções de ácidos húmicos sobre a produ-tividade de soja; Avaliação de extratores de boro em solos cultivados com soja; Fontes e doses de molibdênio para enriquecimento de sementes e seus efeitos no rendimento da soja; Monitoramento de plantas daninhas na cultura da soja no Estado do Tocantins; Manejo de plantas daninhas em cultivos orgânicos de soja por meio de descarga elétrica; Controle de plantas daninhas em soja orgânica com uso da roçadeira articulada; Estudo da interação entre glifosato, micronutrientes e fungicida em soja RR; BRS Juliana RR - variação da cor do hilo de sementes de soja; Desperdícios na colheita mecânica da soja no Paraná e no Brasil na safra 2006/07; Efeito da antecipação e do retardamento de colheita na qualidade fisiológica e nos teores de óleo e proteina das sementes de soja cultivar Valiosa RR; Antecipação de colheita de sementes de soja com dessecação em pré-colheita; Efeito da aplicação de glyphosate como dessecante em pré-colheita sobre a qualidade de semente de soja; Aplicação de glyphosate como dessecante em pré-colheita em semente de soja: efeito sobre a produtividade; Suscetibilidade de genótipos de soja à produção de semente esverdeada, produzidos em condições de estresses hídrico e térmico; Qualidade e produtividade de sementes de soja em função de doses de potássio produzidas em cerrado de Roraima em 2006; Qualidade e produtividade de sementes de soja produzidas em cerrado de Roraima, em plantio direto sobre braquiária; Desempenho fisiológico de semente de soja em função do volume de calda no seu tratamento.

Cultivares de soja: macrorregiões 4 e 5 norte e nordeste do Brasil.

Grupo de Maturidade Relativa. Indicação de cultivares por região edafoclimática. Época de Semeadura. População de Plantas. Peso médio de sementes. Mancha olho-de-rã. Cancro da haste. Nematoides de galhas. Cultivares de soja convencional: BRS Carnaúba; BRS Sambaíba; BRS Tracajá; BRS Pérola; BRS 8590. Cultivares de soja transgênica RR: BRS 333RR, BRS Sambaíba RR, BRS 9280RR, BRS 9090RR, BRS 8890RR, BRS 279RR. CULTIVARES DE SOJA TRANSGÊNICA: INTACTA RR2 PROTM; BRS 9180IPRO. Multiplicadores de Sementes de Soja. Parceria FAPCEN. Parceria Fundação Bahia e Fundação Cerrados.

Estrutura de capital : teoria da agência, teoria da sinalização e teoria do controle

Trata da discussão teórica sobre estrutura de capital das empresas tratando das teorias tradicionais que concentraram o debate, bem como da teoria da agência, sinalização e controle cujo desenvolvimento é mais recente. O tema é abordado mostrando a evolução da empresa, evidenciando onde se enquadra a questão da estrutura de capital. Também mostra os testes emp1ricos utilizados na sustentação das teorias