46 research outputs found

    Land cover, land use and malaria in the Amazon: a systematic literature review of studies using remotely sensed data

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    The nine countries sharing the Amazon forest accounted for 89% of all malaria cases reported in the Americas in 2008. Remote sensing can help identify the environmental determinants of malaria transmission and their temporo-spatial evolution. Seventeen studies characterizing land cover or land use features, and relating them to malaria in the Amazon subregion, were identified. These were reviewed in order to improve the understanding of the land cover/use class roles in malaria transmission. The indicators affecting the transmission risk were summarized in terms of temporal components, landscape fragmentation and anthropic pressure. This review helps to define a framework for future studies aiming to characterize and monitor malaria

    Air-filled substrate-integrated waveguide technology for broadband and highly-efficient photonic-enabled antenna systems

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    The combination of microwave photonics, radio-over-fiber (RoF) and air-filled substrate-integrated-waveguide (AFSIW) technology opens many promising pathways to realize robust, broadband, and highly-integrated multi-antenna systems that address the stringent demands of (beyond-)5G wireless applications. In this paper, we demonstrate the potential of such a multi-disciplinary approach by discussing three designs. First, two AFSIW-based photonic-enabled remote antenna units (RAUs) are presented for downlink sub-6GHz RoF. By adopting an extensive full-wave/circuit co-simulation model, the power transfer between the optical and electrical domain is maximized. In the first design, this is done by using a Chebyshev impedance matching network, while the second design exploits conjugate matching. Second, a hybrid integration strategy for compact, broadband and highly efficient mmWave antennas is introduced. Its excellent performance is proven by realizing an on-chip AFSIW stacked patch antenna. In addition, the design facilitates compact integration of the opto-electronic front-end, making it attractive for the realization of next-generation photonic-enabled mmWave planar multi-antenna systems

    Enzimas exógenas em dietas de frangos de corte: desempenho

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    O experimento foi conduzido para avaliar a eficiência de enzimas exógenas em dietas sobre o desempenho de frangos de corte. Um total de 1440 pintos de corte machos (Cobb 500®) foram distribuídos em um delineamento inteiramente casualizado em esquema fatorial 2x2 (duas dietas com diferentes densidades nutricionais; com e sem a adição enzimática) com 8 repetições de 45 aves em cada unidade experimental. As dietas com diferentes densidades nutricionais foram: controle positivo (níveis normais) e um controle negativo (com redução de 4,3 e 4,5% de energia metabolizável; 16,7 e 17,7% de cálcio e 35 e 42,7% de fósforo, nas fases inicial e de crescimento, respectivamente). A suplementação enzimática consistiu da combinação das enzimas fitase (100g t-1) e amilase, xilanase e protease (500g t-1). Foi avaliado o desempenho das aves nas fases de 1 a 21 e 1 a 42 dias de idade. Na fase total de criação, as aves alimentadas com a dieta controle negativo com adição enzimática tiveram consumo de ração (5,97%), peso médio (8,47%), ganho de peso (8,64%) e conversão alimentar (2,92%) melhores (P0,05) ao grupo alimentado com a dieta controle positivo com ou sem enzima. A adição de enzimas exógenas em dieta de frangos de corte com redução de energia metabolizável, cálcio e fósforo, proporciona um consumo de ração, peso vivo médio e ganho de peso similar a uma dieta com níveis nutricionais adequados.The experiment was conducted to evaluate the effect of enzyme efficiency in diets with and without nutrient reduction on the performance of broilers. Thousand and hundred forty male broiler chicks (Cobb 500®) were distributed in a completely randomized design with 4 treatments in a factorial 2x2 (two diets with different nutrient densities, with and without enzyme) with 8 replications of 45 birds. The diets were: positive control (normal) and a negative control (with a reduction of 4.3% and 4.5% of metabolizable energy, 16.7% and 17.7% of calcium and 35% and 42.7% of phosphorus, in initial and growth phases, respectively). The enzyme supplementation consisted of a combination of phytase enzyme (100g t-1) and amylase, xylanase and protease (500g t-1). It was evaluated the performance of birds in phases 1 to 21 and 1 to 42 days old. In the total period, the birds fed with negative control diet with added enzyme had feed intake (5.97%), body weight (8.47%), body weight gain (8.64%) and feed conversion (2.92%) higher (P0.05) to the group fed with positive control diet with or without enzyme. It is concluded that the addition of exogenous enzymes in diets with reduced metabolizable energy, calcium and phosphorus, providing a feed intake, average live weight and weight gain similar to a diet with adequate levels for broiler

    Phosphorus availability in oxidic soils treated with lime and silicate applications

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    Based on the assumption that silicate application can raise soil P availability for crops, the aim of this research was to compare the effect of silicate application on soil P desorption with that of liming, in evaluations based on two extractors and plant growth. The experiment was carried out in randomized blocks with four replications, in a 3 × 3 × 5 factorial design, in which three soil types, three P rates, and four soil acidity correctives were evaluated in 180 experimental plots. Trials were performed in a greenhouse using corn plants in 20-dm³ pots. Three P rates (0, 50 and 150 mg dm-3) were applied in the form of powder triple superphosphate and the soil was incubated for 90 days. After this period, soil samples were collected for routine chemical analysis and P content determination by the extraction methods resin, Mehlich-1 and remaining P. Based on the results, acidity correctives were applied at rates calculated for base saturation increased to 70 %, with subsequent incubation for 60 more days, when P content was determined again. The acidity correctives consisted of: dolomitic lime, steelmaking slag, ladle furnace slag, and wollastonite. Therefore, our results showed that slags raised the soil P content more than lime, suggesting a positive correlation between P and Si in soil. Silicon did not affect the extractor choice since both Mehlich-1 and resin had the same behavior regarding extracted P when silicon was applied to the soil. For all evaluated plant parameters, there was significant interaction between P rates and correctives; highest values were obtained with silicate
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