220 research outputs found

    Modelling economic impacts of deficit irrigated maize in Brazil with consideration of different rainfall regimes

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    Deficit irrigation is often required to cope with droughts and limited water availability. However, to select an appropriate irrigation management, it is necessary to assess when economic impacts of deficit irrigation are acceptable. Thus, the main goal of this study was to evaluate economic water productivity for maize submitted to various levels of water deficits and different irrigation systems. The study was based on two different experiments conducted in Southern Brazil, one using sprinkler irrigation to supplement rainfall and the other using drip irrigation with precipitation excluded by a rainfall shelter to simulate cultivation under dry conditions. Water productivity indicators were calculated referring to: a) actual field collected data, including yields, commodity prices and production costs; and b) a sensitivity analysis to commodity prices and production costs. Alternative centrepivot irrigation scenarios were also developed to assess their feasibility in terms of water use and productivity when irrigation is used to supplement rainfall or when rainfall is scarce. Results show that the feasibility of deficit irrigation is highly influenced by commodity prices and by the irrigation (and water) costs when the irrigation costs are a large part of the production costs. Results also show that deficit irrigation applied when rainfall is abundant is easier to implement than deficit irrigation where rainfall is very scarce, when only a mild stress is economically viable. For well-designed and managed centrepivot systems, results confirm that adopting deficit irrigation when rainfall is scarce is less attractive than under conditions of irrigation to supplement rainfall. It could be concluded that farmers are unlikely to choose a deficit irrigation strategy unless they are facing reduced water availability for irrigatio

    Leucine Supplementation Does Not Improve Muscle Recovery from Resistance Exercise in Young Adults: A Randomized, Double-Blinded, Crossover Study

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    International Journal of Exercise Science 14(2): 486-497, 2021. This study aimed to investigate the effects of free leucine supplementation on muscle recovery from resistance exercise (RE) in young adults. Fourteen untrained subjects (23.9 ± 3.6 years old) underwent RE sessions (leg press and hack squat: three sets of 8-12 reps at 70% 1RM) supplemented with leucine (LEU: two daily doses of 3g) or a placebo (PLA), separated by a seven-day washout period. Following each occasion, participants were evaluated in three subsequent days (24h, 48h, and 72h) for muscle recovery via a repetition-to-failure test. The following markers were assessed: repetition performance, perceived exertion, lactate, creatine kinase, muscle soreness (DOMS), testosterone, and cortisol. No significant difference was observed between LEU and PLA conditions (p \u3e 0.05). Number of repetitions performed in the repetition-to-failure tests, perceived exertion, cortisol, and testosterone:cortisol ratio did not change over time (p \u3e 0.05). Creatine kinase increased immediately after exercise, at 24h, and 48h, and was attenuated at 72h post-exercise, while testosterone, lactate, and DOMS increased at 24h post-exercise (p \u3c 0.05) and remained elevated up to 72h. All outcomes were similar between LEU and PLA. Results indicate that a 6g daily dose of free leucine supplementation does not improve muscle recovery following lower-limb RE in untrained young adults

    Estratégia de Controle Cooperativo em Unidades de Geração Distribuídas Integrada a Sistemas de Armazenamento de Energia Elétrica / Cooperative Control Strategy in Distributed Generation Units Distributed Generation Units Integrated with Power Storage Systems

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    O aumento do nível de penetração de fontes re[1]nováveis conectadas a rede elétrica através de conversores de potência, pode provocar instabilidades em microrredes CA devido à natureza não-despachável em potência desses sistemas. A integração de sistemas de armazenamento de energia elétrica ao inversor do gerador distribuído pode suavizar a injeção de potência no ponto de acoplamento comum (PAC), contribuindo para a estabilidade de tensão e de frequência do sistema de potência. Neste trabalho, propõe-se uma estratégia de controle cooperativo para regular a tensão do barramento CC integrada a uma estrutura de armazenamento de um sistema de geração distribuída para minimizar eventuais flutuações de tensão e de frequência no PAC. Comparações com métodos tradicionais de controle são realizados para avaliar a efetividade do método proposto. A validação da estratégia de controle é realizada por meio de resultados experimentais

    Branched-chain amino acids do not improve muscle recovery from resistance exercise in untrained young adults.

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    The purpose of this study was to investigate the effects of BCAA supplementation on muscle recovery from resistance exercise (RE) in untrained young adults. Twenty-four young adults (24.0 ± 4.3 years old) were assigned to 1 of 2 groups (n = 12 per group): a placebo-supplement group or a BCAA-supplement group. The groups were supplemented for a period of 5 days. On day 1 and 3, both groups underwent a RE session involving two lower body exercises (hack squat and leg press) and then were evaluated for muscle recovery on the 3 subsequent moments after the RE session [30 min (day 3), 24 h (day 4), and 48 h (day 5)]. The following indicators of muscle recovery were assessed: number of repetitions, rating of perceived exertion in the last RE session, muscle soreness and countermovement jump (CMJ) during recovery period (30 min, 24 h, and 48 h after RE session). Number of repetitions remained unchanged over time (time, P > 0.05), while the rating of perceived exertion increased (time, P  0.05). Muscle soreness increased (time, P  0.05). The results indicate that BCAA supplementation does not improve muscle recovery from RE in untrained young adults

    Frequência alélica do SNP c.909t>c do gene HSF1 em bovinos.

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    A capacidade adaptativa de um indivíduo frente às alterações climáticas influencia sua reprodução, produtividade e sobrevivência. A utilização de marcadores moleculares para a seleção genética de animais mais termotolerantes pode propiciar um aumento na eficiência produtiva dos rebanhos e, por conseguinte, na demanda de produtos de origem animal

    Superior Effects of High-Intensity Interval vs. Moderate-Intensity Continuous Training on Endothelial Function and Cardiorespiratory Fitness in Patients With Type 1 Diabetes: A Randomized Controlled Trial

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    This study aimed to compare the effect of high-intensity interval training (HIIT) with moderate-intensity continuous training (MCT) on endothelial function, oxidative stress and clinical fitness in patients with type 1 diabetes. Thirty-six type 1 diabetic patients (mean age 23.5 ± 6 years) were randomized into 3 groups: HIIT, MCT, and a non-exercising group (CON). Exercise was performed in a stationary cycle ergometers during 40 min, 3 times/week, for 8 weeks at 50–85% maximal heart rate (HRmax) in HIIT and 50% HRmax in MCT. Endothelial function was measured by flow-mediated dilation (FMD) [endothelium-dependent vasodilation (EDVD)], and smooth-muscle function by nitroglycerin-mediated dilation [endothelium-independent vasodilation (EIVD)]. Peak oxygen consumption (VO2peak) and oxidative stress markers were determined before and after training. Endothelial dysfunction was defined as an increase < 8% in vascular diameter after cuff release. The trial is registered at ClinicalTrials.gov, identifier: NCT03451201. Twenty-seven patients completed the 8-week protocol, 9 in each group (3 random dropouts per group). Mean baseline EDVD was similar in all groups. After training, mean absolute EDVD response improved from baseline in HIIT: + 5.5 ± 5.4%, (P = 0.0059), but remained unchanged in MCT: 0.2 ± 4.1% (P = 0.8593) and in CON: −2.6 ± 6.4% (P = 0.2635). EDVD increase was greater in HIIT vs. MCT (P = 0.0074) and CON (P = 0.0042) (ANOVA with Bonferroni). Baseline VO2peak was similar in all groups (P = 0.96). VO2peak increased 17.6% from baseline after HIIT (P = 0.0001), but only 3% after MCT (P = 0.055); no change was detected in CON (P = 0.63). EIVD was unchanged in all groups (P = 0.18). Glycemic control was similar in all groups. In patients with type 1 diabetes without microvascular complications, 8-week HIIT produced greater improvement in endothelial function and physical fitness than MCT at a similar glycemic control

    Metabolizable energy and metabolizability coefficients of moringa and bocaiuva for slow-growing broilers at different ages.

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    This study aimed to determine nutrient metabolizability coefficients and apparent metabolizable energy (AME) and nitrogen-corrected AME (AMEn) values of moringa leaf meal and bocaiuva pulp for slow-growing broilers. Three hundred and fifty 1-day-old chicks of the Red Naked Neck line were allocated to five treatments in a completely randomized design with seven replicates of 10 birds. Treatments consisted of a control diet and four test diets. The proportion of ingredients evaluated in the test diets was 20% moringa leaf meal and bocaiuva pulp and 40% corn and soybean meal. The total excreta collection method was applied with 1% ferric oxide included in the diets as a marker of start and end of collection, in the starter, grower and finisher phases. The metabolizability coefficients of dry matter, crude protein and ether extract and the AME and AMEn values of moringa leaf meal, bocaiuva pulp, corn and soybean meal were determined. Data were subjected to analysis of variance and means were compared by Tukey?s test at the 5% probability level. The protein from moringa leaf meal and the fat from bocaiuva pulp are highly metabolizable by birds at different ages. The AME and AMEn values of moringa leaf meal ranged from 2557 to 2868 Kcal/kg and 2205 to 2479 Kcal/kg, respectively. In bocaiuva pulp, AME and AMen ranged between 2680 and 3119 Kcal/kg and 2483 and 2490 Kcal/kg, respectively. Therefore, the alternative ingredients can be used in the formulation of diets for slow-growing broilers to partially replace corn and soybean meal
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