971 resultados para Northeast. Semiarid. Native Goats. Production System. Productive Performance


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Crop models are simplified mathematical representations of the interacting biological and environmental components of the dynamic soil–plant–environment system. Sorghum crop modeling has evolved in parallel with crop modeling capability in general, since its origins in the 1960s and 1970s. Here we briefly review the trajectory in sorghum crop modeling leading to the development of advanced models. We then (i) overview the structure and function of the sorghum model in the Agricultural Production System sIMulator (APSIM) to exemplify advanced modeling concepts that suit both agronomic and breeding applications, (ii) review an example of use of sorghum modeling in supporting agronomic management decisions, (iii) review an example of the use of sorghum modeling in plant breeding, and (iv) consider implications for future roles of sorghum crop modeling. Modeling and simulation provide an avenue to explore consequences of crop management decision options in situations confronted with risks associated with seasonal climate uncertainties. Here we consider the possibility of manipulating planting configuration and density in sorghum as a means to manipulate the productivity–risk trade-off. A simulation analysis of decision options is presented and avenues for its use with decision-makers discussed. Modeling and simulation also provide opportunities to improve breeding efficiency by either dissecting complex traits to more amenable targets for genetics and breeding, or by trait evaluation via phenotypic prediction in target production regions to help prioritize effort and assess breeding strategies. Here we consider studies on the stay-green trait in sorghum, which confers yield advantage in water-limited situations, to exemplify both aspects. The possible future roles of sorghum modeling in agronomy and breeding are discussed as are opportunities related to their synergistic interaction. The potential to add significant value to the revolution in plant breeding associated with genomic technologies is identified as the new modeling frontier.

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O café é originário das florestas tropicais da Etiópia e do Sudão, crescendo sobre uma canópia diversa. Devido ao facto de haver uma tendência para o desaparecimento do sombreamento tradicional e consequente perda de biodiversidade, os sistemas de certificação oferecem a oportunidade de aproximar objectivos económicos, sociais e ambientais de modo a beneficiar os agricultores. Este estudo tem como objectivo dar a conhecer a todos os intervenientes da cadeia de custódia, principalmente aos consumidores, qual a certificação que podem optar por se a sua principal preocupação quando tomam um café for a natureza. Caracterizou-se o valor ecológico do sistema de produção sustentável e do sistema convencional. Analisaram-se e comparam-se os diferentes critérios ambientais dos sistemas de certificação, através da construção de uma matriz. Os resultados sugerem que a certificação que melhor responde ao pretendido é a Rainforest Alliance, no entanto, a dupla ou tripla certificação parecem ser também boas opções. ABSTRACT; Coffee originates in Ethiopia and Sudan’s ram forests, growing above a diverse canephora. Due to the fact that there is a tendency to the vanishing of traditional shadowing and consequent loss of biodiversity, certification schemes offer the opportunity of bringing together economical, social and environmental goals allowing benefits to farmers. This study aims to bring cognizance to every intervenient of the custody chain, mainly to consumers, which certification scheme to choose if their major concern when drinking a coffee is nature. The ecological value of sustainable production system has been characterized as well as the conventional system. Different environmental criteria of certification schemes have been analysed and compared trough the construction of an evaluation template. Results suggest that the certification that better suits the desired goal is the Rainforest Alliance, but double or triple certification also appear as options that might be followed.

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O objetivo deste estudo foi avaliar a ocorrência de resposta compensatória no desempenho produtivo de juvenis de tilápia do Nilo Oreochromis niloticus, linhagem GIFT, submetidos a diferentes estratégias alimentares. Foram utilizados 135 juvenis de tilápia, distribuídos em nove tanques de polietileno de 100L cada. As estratégias testadas foram: grupo controle (alimentado todo dia), grupo alimentado por cinco dias seguidos de dois dias de restrição de alimento (5A/2R) e grupo alimentado por quatro dias seguidos de três dias de restrição de alimento (4A/3R). Foram avaliados parâmetros físico-químicos da água e de desempenho produtivo. Os resultados foram submetidos à análise de variância, e as médias foram comparadas pelo teste Tukey, a 5% de probabilidade. A qualidade de água, o fator de condição e a conversão alimentar não foram influenciados pela estratégia alimentar. O grupo alimentado com a estratégia 5A/2R apresentou peso final, ganho de peso e taxa de crescimento específico semelhantes ao grupo continuamente alimentado (7,8 e 9,2g; 6,4 e 7,8g e 2,7 e 3,0% dia-1, para peso final, ganho de peso e taxa de crescimento especifico, respectivamente). A estratégia 4A/3R apresentou os piores resultados de desempenho produtivo, e a estratégia 5A/2R pode ser usada na alimentação de juvenis de tilápia do Nilo sem prejuízo ao desempenho produtivo, possibilitando inclusive redução de até 22,5% na quantidade de alimento ofertada.

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O Brasil ocupa as posições de maior produtor e exportador mundial de carne bovina, com a região Centro-Oeste respondendo por 35% do abate nacional, em 2010. Entretanto, faz-se necessário valorizar o planejamento, o controle e a gestão empresarial nas propriedades produtoras, visando ao lucro na atividade. O presente estudo objetivou analisar e avaliar a viabilidade econômica da produção de bovinos de corte, em Camapuã (MS), a fim de identificar os itens relevantes aos custos da atividade. Como direcionador dos custos variáveis, no custo operacional efetivo, o suplemento mineral fornecido aos animais e a mão de obra mostraram-se relevantes para a gestão do sistema de produção, representando, aproximadamente, 71% dos custos. Com base nos resultados apresentados, pôde-se concluir que a propriedade apresenta boa lucratividade (superior a 20%). Verificou-se, ainda, com base no fluxo de caixa, taxa interna de retorno de 13,13% e capital inicial investido retornando em, aproximadamente, 7 anos, com resultados atrativos para o investimento, neste segmento agropecuário. O estudo proporcionou um parâmetro de custo para o produtor pecuarista, podendo contribuir para um melhor planejamento de atividades, em que, apesar dos altos investimentos iniciais, possivelmente, poderá reduzir seus custos, com o manejo racional no sistema produtivo, o que seria mais atrativo para o mercado, tornando mais viáveis as suas atividades de produção e comercialização do produto.

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Cada vez mais, os principais objetivos na indústria é a produção a baixo custo, com a máxima qualidade e com o tempo de fabrico o mais curto possível. Para atingir esta meta, a indústria recorre, frequentemente, às máquinas de comando numérico (CNC), uma vez que com esta tecnologia torna se capaz alcançar uma elevada precisão e um tempo de processamento mais baixo. As máquinas ferramentas CNC podem ser aplicadas em diferentes processos de maquinagem, tais como: torneamento, fresagem, furação, entre outros. De todos estes processos, o mais utilizado é a fresagem devido à sua versatilidade. Utiliza-se normalmente este processo para maquinar materiais metálicos como é o caso do aço e dos ferros fundidos. Neste trabalho, são analisados os efeitos da variação de quatro parâmetros no processo de fresagem (velocidade de corte, velocidade de avanço, penetração radial e penetração axial), individualmente e a interação entre alguns deles, na variação da rugosidade num aço endurecido (aço 12738). Para essa análise são utilizados dois métodos de otimização: o método de Taguchi e o método das superfícies. O primeiro método foi utilizado para diminuir o número de combinações possíveis e, consequentemente, o número de ensaios a realizar é denominado por método de Taguchi. O método das superfícies ou método das superfícies de resposta (RSM) foi utilizado com o intuito de comparar os resultados obtidos com o método de Taguchi, de acordo com alguns trabalhos referidos na bibliografia especializada, o RSM converge mais rapidamente para um valor ótimo. O método de Taguchi é muito conhecido no setor industrial onde é utilizado para o controlo de qualidade. Apresenta conceitos interessantes, tais como robustez e perda de qualidade, sendo bastante útil para identificar variações do sistema de produção, durante o processo industrial, quantificando a variação e permitindo eliminar os fatores indesejáveis. Com este método foi vi construída uma matriz ortogonal L16 e para cada parâmetro foram definidos dois níveis diferentes e realizados dezasseis ensaios. Após cada ensaio, faz-se a medição superficial da rugosidade da peça. Com base nos resultados obtidos das medições da rugosidade é feito um tratamento estatístico dos dados através da análise de variância (Anova) a fim de determinar a influência de cada um dos parâmetros na rugosidade superficial. Verificou-se que a rugosidade mínima medida foi de 1,05m. Neste estudo foi também determinada a contribuição de cada um dos parâmetros de maquinagem e a sua interação. A análise dos valores de “F-ratio” (Anova) revela que os fatores mais importantes são a profundidade de corte radial e da interação entre profundidade de corte radial e profundidade de corte axial para minimizar a rugosidade da superfície. Estes têm contribuições de cerca de 30% e 24%, respetivamente. Numa segunda etapa este mesmo estudo foi realizado pelo método das superfícies, a fim de comparar os resultados por estes dois métodos e verificar qual o melhor método de otimização para minimizar a rugosidade. A metodologia das superfícies de resposta é baseada num conjunto de técnicas matemáticas e estatísticas úteis para modelar e analisar problemas em que a resposta de interesse é influenciada por diversas variáveis e cujo objetivo é otimizar essa resposta. Para este método apenas foram realizados cinco ensaios, ao contrário de Taguchi, uma vez que apenas em cinco ensaios consegue-se valores de rugosidade mais baixos do que a média da rugosidade no método de Taguchi. O valor mais baixo por este método foi de 1,03μm. Assim, conclui-se que RSM é um método de otimização mais adequado do que Taguchi para os ensaios realizados. Foram obtidos melhores resultados num menor número de ensaios, o que implica menos desgaste da ferramenta, menor tempo de processamento e uma redução significativa do material utilizado.

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Dissertação (mestrado)—Universidade de Brasília, Centro de Estudos Avançados Multidisciplinares, Programa de Pós-Graduação em Desenvolvimento, Sociedade e Cooperação Internacional, 2016.

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The land suitability evaluation is used to establish land zonings for agriculture activities. Geographic information systems (GIS) are useful for integrating different attributes necessaries to define apt and not apt lands. The present study had as main objective to describe procedures to define land suitability using GIS tools, soils maps and data soils profiles data, emphasizing procedures to define soil atributes. The area studied was the watershed of Córrego Espraiado, Ribeirão Preto-SP, located on the recharging area of the Guarani Aquifer, with approximately 4,130 ha and predominance of sugar cane culture. The database project was developed using the GIS Idrisi 32. The land suitability evaluation was done considering the intensive agricultural production system predominant in the watershed, adjusted for the vulnerability of the areas of recharge and for the methodology of GIS tools. Numerical terrain models (NTM) had been constructed for cation exchange capacity, basis saturation, clay content and silt+clay content using kriging (geostatistical interpolator), and for aluminum saturation using the inverse-square-distance. Boolean operations for handling geographic fields (thematic maps and NTM) to produce information plans are described and a land suitability map obtained by GIS tools is presented, indicating that 85% of watershed lands are apt to annual cultures.

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Doutoramento em Engenharia Agronómica - Instituto Superior de Agronomia - UL

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Citrus are a group of fruit species, quite heterogeneous in many aspects, including chemical composition of the fruit. Since ancient times, some citrus fruits were used to prevent and cure human diseases. In the recent decades, it has been demonstrated that fruits can actually help prevent and cure some diseases and above all, they are essential in a balanced diet. Citrus fruits, as one of the groups of fruit species, with greater importance in the world, have been studied for their effects on human health. Some species of citrus were referred as potential antioxidant based therapy for heart disease, cancer and inflammation. Fruit peels and seeds have also high antioxidant activity. The health benefits of citrus fruit have mainly been attributed to the high level of bioactive compounds, such as phenols (e.g., flavanone glycosides, hydroxycinnamic acids), carotenoids and vitamin C. These compounds are present in the fruit pulp and hence in the juice. But some bioactive compounds can be found in parts of the fruit which usually are not used for human food. The content of bioactive compounds depends on the species and cultivar, but also depends on the production system followed in the orchard. Citrus fruits, their derivatives and their by-products (peel, pulp and oil) are reach in different bioactive compounds and its maturity, postharvest and agroindustry processes influence their composition and concentration. The aim of this chapter was to review the main bioactive compounds of the different components of citrus and their relationship to health.

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ABSTRACT: Ruminal gases, particularly methane, generated during the fermentative process in rumen, represent a partial loss of feed energy and are also pointed to as an important factors in greenhouse effect. This study aimed at quantifying methane (CH 4) emission rates from lactating and dry cows and heifers, 24 month-old in average, on pasture under Southeast Brazil tropical conditions, using the tracer gas technique, sulphur hexafluoride (SF 6), four animals per category, distributed in four blocks. Measurements were performed in February and June, 2002, with Holstein and Brazilian Dairy Crossbred (Holstein ¾ x Gir (Zebu) ¼), maintained on fertilized Tanzania-grass (Panicum maximum Jacq. cv. Tanzania) and fertilized Brachiaria-grass (Brachiaria decumbens cv. Basilisk) pastures. Heifers of both breeds were maintained on unfertilized Brachiaria-grass to simulate conditions of extensive cattle farming systems. CH 4 and SF 6 levels were measured with gas chromatography. Differences in CH4 emissions were measured (p < 0.05) for genetical groups. Holstein produced more methane (299.3g day?1) than the Crossbred (264.2 g day?1). Lactating cows produced more methane (353.8 g day?1) than dry cows (268.8 g day?1) and heifers (222.6 g day?1). Holstein, with greater milk production potential, produced less CH4 (p < 0.05) per unit of dry matter intake (19.1 g kg?1) than the Crossbred (22.0 g kg?1). Methane emission by heifers grazing fertilized pasture (intensive system) was 222.6 g day?1, greater (p < 0.05) than that of heifers on unfertilized pasture (179.2 g day?1). Methane emission varied as function of animal category and management intensity of production system.

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The program PROBIODIESEL from the Ministry of Science and Technology has substantially increased glycerine, obtained as a sub-product of biodiesel production process, making it necessary to seek alternatives for the use of this co-product. On the other hand, herbicides although play a role of fundamental importance in the agricultural production system in force, have been under growing concern among the various segments of society because of their potential environmental risk. In this work, we used glycerin in microemulsion systems for application of herbicides, to improve efficiency and lower environmental pollution caused by the loss of those products to the environment. To obtain the systems of microemulsinados were used Unitol L90 NP and Renex 40 as surfactants, butanol as co-surfactant, coconut oil as oil phase and aqueous phase as we used solutions of glycerin + water. Through the determination of phase diagrams, the microemulsion region was found in the system E (L90 Unitol, coconut oil and glycerin + water 1:1). Three points were chosen to the aqueous phase rich in characterization and application in the solubilization of glyphosate and atrazine. Three experiments were performed in Horta, Department of Plant Sciences, Plant Science Sector, UFERSA, Mossoró-RN. The first experiment was conducted in randomized complete blocks with 20 treatments and four replications. The treatments consisted of five doses of the herbicide glyphosate (0.0, 0.45, 0.9, 1.35 and 1.8 L ha-1) diluted with four sauces: C1, C2, C3 (microemulsions) and C4 (water). The phytotoxicity of Brachiaria brizantha was measured at 7, 14, 28 and 60 DAA (days after application). At 60 DAA, we evaluated the biomass of plants. The second experiment was developed in randomized complete blocks with 20 treatments and four repetitions. The treatments consisted of five doses of the herbicide atrazine (0.0, 0.4, 0.8, 1.6 and 2.4 L ha-1) diluted with four sauces: C1, C2, C3 (microemulsions) and C4 (water). The phytotoxicity on Zea mays and Talinum paniculatum was evaluated at 2, 7, 20 DAA. The experiment III was developed in randomized complete blocks with 16 treatments and three repetitions. The treatments consisted of 16 combinations among the constituents of the microemulsion: Unitol L90 surfactant (0.0, 1.66, 5.0, 15 %) and glycerin (0.0, 4.44, 13.33 and 40.0 %). The phytotoxicity on Zea mays was evaluated at 1, 7 and 14 DAA. At 14 DAA, we evaluated the biomass of plants. The control plants using the microemulsions was lower than in the water due to the poisoning caused by the initial microemulsions in the leaves of the plants, a fact that hinders the absorption and translocation of the herbicide. There was no toxicity in Zea mays plants caused by the herbicide, however, were highly intoxicated by microemulsions. T. paniculatum was better controlled in spraying with the microemulsions, regardless of the dose of the herbicide. The glycerine did not cause plant damage. Higher poisoning the plants are caused by tensoactive Unitol L90 and higher rates occur with the use of higher concentrations of surfactant and glycerin, or microemulsion. The microemulsions used hampered the action of glyphosate in controlling B. brizantha and caused severe poisoning in corn, and these poisonings attributed mainly to the action of surfactant

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The multiphase flow occurrence in the oil and gas industry is common throughout fluid path, production, transportation and refining. The multiphase flow is defined as flow simultaneously composed of two or more phases with different properties and immiscible. An important computational tool for the design, planning and optimization production systems is multiphase flow simulation in pipelines and porous media, usually made by multiphase flow commercial simulators. The main purpose of the multiphase flow simulators is predicting pressure and temperature at any point at the production system. This work proposes the development of a multiphase flow simulator able to predict the dynamic pressure and temperature gradient in vertical, directional and horizontal wells. The prediction of pressure and temperature profiles was made by numerical integration using marching algorithm with empirical correlations and mechanistic model to predict pressure gradient. The development of this tool involved set of routines implemented through software programming Embarcadero C++ Builder® 2010 version, which allowed the creation of executable file compatible with Microsoft Windows® operating systems. The simulator validation was conduct by computational experiments and comparison the results with the PIPESIM®. In general, the developed simulator achieved excellent results compared with those obtained by PIPESIM and can be used as a tool to assist production systems development

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The occurrence of heavy oil reservoirs have increased substantially and, due to the high viscosity characteristic of this type of oil, conventional recovery methods can not be applied. Thermal methods have been studied for the recovery of this type of oil, with a main objective to reduce its viscosity, by increasing the reservoir temperature, favoring the mobility of the oil and allowing an increasing in the productivity rate of the fields. In situ combustion (ISC) is a thermal recovery method in which heat is produced inside the reservoir by the combustion of part of the oil with injected oxygen, contrasting with the injection of fluid that is heated in the surface for subsequent injection, which leads to loss heat during the trajectory to the reservoir. The ISC is a favorable method for recovery of heavy oil, but it is still difficult to be field implemented. This work had as an objective the parametric analysis of ISC process applied to a semi-synthetic reservoir with characteristics of the Brazilian Northeast reservoirs using vertical production and vertical injection wells, as the air flow injection and the wells completions. For the analysis, was used a commercial program for simulation of oil reservoirs using thermal processes, called Steam, Thermal and Advanced Processes Reservoir Simulator (STARS) from Computer Modelling Group (CMG). From the results it was possible to analyze the efficiency of the ISC process in heavy oil reservoirs by increasing the reservoir temperature, providing a large decrease in oil viscosity, increasing its mobility inside the reservoir, as well as the improvement in the quality of this oil and therefore increasing significantly its recovered fraction. Among the analyzed parameters, the flow rate of air injection was the one which had greater influence in ISC, obtaining higher recovery factor the higher is the flow rate of injection, due to the greater amount of oxygen while ensuring the maintenance of the combustion front

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In recent decades, the national and international media contexts, in particular television media, significantly changed. The role that social networks, in particular Facebook, have taken as a content diffusion platform is unquestionable. Nowadays, traditional media (radio, newspaper, television) use the Web’s potential to distribute news content (Canelas, 2011). Currently, all TV news channels in Portugal have a website or a page on social networks. TV stations have increased communication channels with the public on digital platforms and study strategies that promote the participation and interaction with the news content (Cazajeira, 2015). The TV / Internet convergence will not only reach the content, but also the consumer, who becomes an interactive and participative audience. This reality imposes on journalism a continuous and updated news production system, dependent on a user being permanently connected to the Internet (Cazajeira, 2015). In fact, a report launched by an autonomous institution that has the function of supervising and regulating the media Portugal (ERC, 2015), confirms the relevance that social media has assumed in the publication and consumption of news. Social networks are recognised as one of the most important means for news media consultation, right after television, and the practice of sharing news is very common among consumers of online news in Portugal. Furthermore, when compared to other countries analysed by Reuters Institute (Newman, Levy, & Nielsen, 2015), Portuguese consumers are those who make the most comments to online news, preferring social networks to news sites. Considering the importance of new online platforms for journalism, this study aims to present a quantitative analysis of user participation on the Facebook pages of the three Portuguese TV news channels, specifically RTP3, SIC Notícias and TVI24, between 8 and 14 February 2016. To track this participation, the following parameters were used: the "like" button as a way to study the demonstration of publication interest; "sharing" of a particular element, be it a photo, a video or a text, on the user Timeline, the Timeline of a friend or by private message. This monitoring is important to understand the dissemination of news content; and the comments area. The number of comments will help understand the dynamics and the discussion that the publication has on the public. The results of 1063 posts indicate that of the analysed parameters - "Like", "Comment", and "Share" – the one with the greatest power of participation among the users of the pages of the three Portuguese TV news channels is the "Like" system, followed by "Share" and then "Comment". The theme that generates the most user participation with "Likes" and “Comments” parameters are "Science and Technology", “Education” and “Humorous/Satirical/Unusual”. Finally, the publications available end of the night (10pm-1am) has better participation rates.

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In recent decades, the national and international media contexts, in particular television, media significantly changed. Although they were not created for the purpose, the role that social networks, in particular Facebook, have taken as a content diffusion platform is unquestionable. Nowadays, traditional media (radio, newspaper, television) use the Web’s potential to distribute news content (Canelas, 2011). Currently, all TV news channels in Portugal have a website or a page on social networks. TV stations have increased communication channels with the public on digital platforms and study strategies that promote the participation and interaction with the news content (Cazajeira, 2015). The TV / Internet convergence will not only reach the content, but also the consumer, who becomes an interactive and participative audience. This reality imposes on journalism a continuous and updated news production system, dependent on a user being permanently connected to the Internet (Cazajeira, 2015). In fact, an ERC report (2015) confirms the relevance that social media has assumed in the publication and consumption of news. Social networks are recognised as one of the most important means for news media consultation, right after television, and the practice of sharing news is very common among consumers of online news in Portugal. Furthermore, when compared to other countries analysed by Reuters Institute (Newman, Levy, & Nielsen, 2015), Portuguese consumers are those who make the most comments to online news, preferring social networks to news sites. Considering the importance of new online platforms for journalism, this study aims to present a quantitative analysis of user participation on the Facebook pages of the three Portuguese TV news channels, specifically RTP3, SIC Notícias and TVI24, between 8 and 14 February 2016. To track this participation, the following parameters were used: the "like" button as a way to study the demonstration of publication interest; "sharing" of a particular element, be it a photo, a video or a text, on their own Timeline, the Timeline of a friend or by private message. This monitoring is important to understand the dissemination of news content; and the comments area. The number of comments will help understand the dynamics and the discussion that the publication has on the public. The results of 1063 posts indicate that of the analysed parameters - "Like", "Comment", and "Share" – the one with the greatest power of participation among the users of the pages of the three Portuguese TV news channels is the "Like" system, followed by "Share" and then "Comment". Analysing the thematic that create the most user participation with "Likes" and “Comments” parameters are "Science and Technology". “Education” and “Humorous/Satirical/Unusual Finally, the publications available end of the night (10pm-1am) has better participation rates.