949 resultados para Semi-arid region
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Pós-graduação em Agronomia (Genética e Melhoramento de Plantas) - FCAV
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Pós-graduação em Agronomia (Irrigação e Drenagem) - FCA
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A Bacia Bauru (Cretáceo Superior), acumulou uma seqüência sedimentar continental essencialmente arenosa. Numa fase inicial desértica, o seu substrato basáltico foi soterrado por extensa e monótona cobertura de areias eólicas com intercalações subordinadas de depósitos de loesse. O relevo original do substrato favoreceu a formação de uma drenagem regional endorrêica, sob clima semi-árido, propiciando assim condições de formação do Paleopantanal Araçatuba. Os depósitos paludiais (Formação Araçatuba) constituem estratos tabulares de siltitos e arenitos de cor cinza claro esverdeado típica, eventualmente cimentados por carbonato de cálcio. Moldes e pseudomorfos de cristais de gipsita e dolomita foram identificados na unidade. Aparentemente, estão associados com gretas de ressecação, marcas de raízes e intervalos com laminação tipo climbing ripple, que indicam ambiente de águas salinas rasas e relativamente calmas, submetidas a fases de exposição subaérea e ressecação. Nos limites da área de ocorrência da Formação Araçatuba, as unidades arenosas podem exibir feições sigmóides e estratificação contorcida, comuns em depósitos deltaicos marginais. A Formação Araçatuba é contornada e posteriormente encoberta por depósitos eólicos da Formação Vale do Rio do Peixe.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Electromagnetic methods have been extensively applied in the prospecting of sulphide bodies and other conducting materials. The interpretation of e. m. data is based on the results obtained either with reduced scale or analytical modelling. In most models, the host rocks, the overburden as well as the halo of disseminated sulphides are considered highly resistive although in nature they are often weakly conductive. Presence of a well-developed conducting overburden in tropical and sub-tropical regions and a saline rich crustal layer in semi-arid regions have been found to modify significantly the e. m. anomalies in practice. Therefore, the parameters of the target, determined on the basis of simple models where the presence of the conducting environment is neglected, are found to be in considerable error. The effects of the overburden on the e. m. anomalies of a dipping tabular ore body were studied with reduced scale models for varying response parameters of both the overburden and the orebody, and also for different depths and dips of the target. The overburden and the orebody were represented by metallic sheets of varying thickness in the scale model developed in accordance with the law of electromagnetic similitude. The results of these investigations show that the overburden affects the anomaly by causing: a) phase rotation; b) amplitude reduction; c) base level displacement; d) reversion of the quadrature; and e) appearance of an extra peak in the quadrature in the case of low dipping models. The last two effects complicate the quantification of the anomalies but, on the other hand, provide a qualitative indication of the response parameters of both the ore body and the overburden. The results were assembled in the form of Argand diagrams and, finally, an interpretation scheme is suggested for the e. m. field data on the basis of these diagrams.
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This work aimed to evaluate the carcass yields, commercial cuts and non-carcass components of Santa Inês lambs fed with 30, 40, 50 or 60% of oldman saltbush hay with concentrated. Were used 32 castrated lambs at 8 months old and initial body weight of 22 + 1.97kg, housed individually and slaughtered after 60 days of feedlot. The weights of hot and cold carcass decreased linearly with the inclusion of saltbush hay in the diet, however, there was no effect for true carcass yield and commercial cuts: shoulder (19.26%), neck (8.52%) ribs (26.57%) and leg (33.88%). There was a linear decrease for ribeye area and fat thickness when the level of hay in the diet increased. The weights and yields of skin, liver, heart, kidneys with perirenal fat, omental and mesenteric fats decreased linearly with the inclusion of hay in the diet, while the content (%) of gastrointestinal tract increased. The increased proportion of saltbush hay in the diet of lambs provided adequate true carcass yield and commercial cuts, however, reduces the ribeye area and fat thickness, important measurements in the qualitative evaluation of the lamb's carcass.
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The almost complete absence or misdistribution of water as a natural resource frequently constitute a limiting factor for plant growth and development in the semi-arid northeastern Brazil. In this context, the use of appropriate irrigation techniques is an essential and indispensable factor for proper functioning of the primary and secondary metabolisms in plants. This study aimed to assess the metabolism of the Syrah grapevine in the semi-arid northeastern Brazil, by using three irrigation strategies (controlled deficit irrigation [CDI], deficit irrigation [DI], and full irrigation [FI]). The research was conducted at Embrapa Semiarid (Embrapa-Brazilian Agricultural Research Corporation), Experimental Field of Bebedouro, municipality of Petrolina, state of Pernambuco, Brazil. The statistical design was randomized blocks, with a 3 x 6 factorial scheme. Six samplings were performed throughout the experiment cycle at 54, 60, 73, 87, 101, and 115 days after pruning (DAP). We analyzed the total soluble sugars, reducing sugars, total soluble protein, and invertase activity. Analysis of variance and the F test were performed for all analyzed variables. The means were compared using the Tukey test at 5% significance. At the end of the experiment cycle, DI was found to increase the average acid invertase activity in the plant cell wall. Further, by the end of the experiment cycle, the total soluble sugars and reducing sugars increased in all plants in the three irrigation strategies. Thus, we conclude that it is possible to reduce water consumption in vineyards of the semi-arid northeastern Brazil, without significantly affecting the protein and sugar metabolisms in the plants.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Caracterização estrutural do Lineamento de Piúma e sua influência na porção norte da Bacia de Campos
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The detailed study of the Brazilian continental margin basins became possible with the advancement of geophysical tools, with emphasis on seismic reflection. Characterizing the structural and stratigraphic elements of Brazil’s marginal basins they realized that there was a relationship with structures present on the adjacent continental basement. So many works began to be made to understand this relationship and know the major factors that influenced the evolution of the continental margin. The study area of this work includes the northern portion of the Campos Basin and the continental outcropping adjacent areas, which corresponds to the northern of Rio de Janeiro state and the southern of Espirito Santo state. This area stands an important structural feature of NW-SE direction with a projection to the Campos Basin called Lineamento de Piúma. The outcropping basement rocks belongs to the Ribeira Belt which was bonded to other mobile bands forming the continent Western Gondwana during the Brasiliano Cycle, which later fragmented giving rise to the Atlantic Ocean. The opening of the ocean results on the formation of the marginal basins of Brazil. These basins have continental, transitional and marine facies. On Campos Basin the continental phase resulted on the formation of horsts and grabens bounded by synthetic and antithetic faults. Continuing rifting formed the saline lakes that deposited siliciclastic and carbonate sediments. The transitional phase resulted on thick packages consist of evaporites (halite and anhydrite) that was deposited in lagoon environment, tectonically quiet arid and semi-arid. The marine phase it deposited siliciclastic and carbonate in the Campos Basin resulting in shales, marls, limestones, ritmito, turbidites, sandstones and others. The objective of this study is to investigate the possible continuation... (Complete abstract click electronic access below)
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A culture of resistance in the semi-arid, expressed by mentalities and values, goes against the economic potential of sheep and goat raising, considered as an inferior activity when compared to the cattle raising, historically linked to social status and prestige. This paper attempts to shed light on aspects that make possible to clarify the roots of the cognitive apparatus that supports this view, resorting to it to the production of relevant authors dealing with the issue of displacement of colonizer and livestock in the hinterlands. Ultimately, it seeks evidence of the influence of the historical process of economic and social organization of space on the present.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Pós-graduação em Agronomia (Genética e Melhoramento de Plantas) - FCAV