Produção de milho em plantio direto com adubação nitrogenada e cobertura do solo na pré-safra Corn in no-till system with nitrogen fertilization and soil cover crops preceding

A utilização de plantas de cobertura de solo em pré&#45;safra é uma alternativa para fornecer nitrogênio (N) ao milho e viabilizar o sistema plantio direto nas Regiões Sudeste, Centro&#45;Oeste, Norte e Nordeste, com inverno seco. Este estudo teve o objetivo de avaliar o efeito de doses de N e de espécies de plantas de cobertura, cultivadas em pré&#45;safra, no fornecimento de N e na produtividade de milho em plantio direto. O delineamento experimental foi de blocos ao acaso, com parcelas subdivididas e quatro repetições. O estudo foi desenvolvido de 2000 a 2003. Os tratamentos principais foram constituídos de quatro sistemas de uso e manejo: milho em plantio direto após crotalária (PDcrot); milho em plantio direto após braquiária no primeiro ano e lablab nos dois últimos (PDlab); milho em plantio direto após milheto (PDmil); milho em plantio convencional após pousio (PC); e os secundários de três doses de N em cobertura para o milho (0, 60 e 120 kg ha&#45;1). Foram avaliados, no milho, massa da matéria seca da parte aérea, produtividade de grãos, N acumulado e eficiência de utilização do N. A maior eficiência de utilização do N pelas plantas de milho ocorreu nos sistemas de plantio direto e crotalária em pré&#45;safra e plantio convencional após pousio, que não diferiu entre os dois sistemas e foram superiores à dos sistemas de plantio direto em que foram utilizados lablab e milheto em pré&#45;safra, que também não diferiram entre si. A máxima produtividade de grãos de milho foi de 7.259; 7.234; 6.723 e 6.461 kg ha&#45;1, nas doses de N de 97,1; 120,0; 87,8 e 96,1 kg ha&#45;1 nos sistemas plantio direto e crotalária, plantio convencional, plantio direto e lablab, e plantio direto e milheto em pré&#45;safra, respectivamente (média dos três anos). No cultivo de milho em sistema de plantio direto a utilização de crotalária proporcionou maior produtividade em relação ao milheto e lablab em pré&#45;safra.<br>The use of cover crops preceding corn is an alternative to supply nitrogen (N) and to make no&#45;till system viable regions with dry winter such as in the Southeast, Center&#45;West, North, and Northeast of Brazil. The purpose of this study was to evaluate N levels and the effect of cover plants on N supply and corn yield in no&#45;till system. The study was carried out from 2000 to 2003. The experimental design was randomized blocks, with split&#45;split plots and four replicates. The main plot treatments were four use and management systems: corn in no&#45;till after Crotalaria juncea, corn in no&#45;till after Brachiaria brizantha in the first year and Dolechus lablab in the two last ones (PDlab), corn in no&#45;till after Pennisetum americanum (PDmil) and corn in conventional system after winter fallow (PC) and the subplot treatments were three side&#45;dressed N levels (0, 60 and 120 kg ha&#45;1). Corn aboveground dry mass, yield, accumulated N and N use efficiency were evaluated. N use efficiency by corn was higher in PDcrot and PC in comparison to PDlab and PDmil, which showed a similar response. The maximum corn yield was 7,259; 7,234; 6,723 and 6,461 kg ha&#45;1, with N levels of 97.1, 120.0, 87.8 and 96.1 kg ha&#45;1 in PDcrot, PC, PDlab and PDmil, respectively. Grain yield in no&#45;tillage&#45;corn after Crotalaria cover crop was higher than that following millet and lablab

Vorapaxar in the secondary prevention of atherothrombotic events

Item does not contain fulltextBACKGROUND: Thrombin potently activates platelets through the protease-activated receptor PAR-1. Vorapaxar is a novel antiplatelet agent that selectively inhibits the cellular actions of thrombin through antagonism of PAR-1. METHODS: We randomly assigned 26,449 patients who had a history of myocardial infarction, ischemic stroke, or peripheral arterial disease to receive vorapaxar (2.5 mg daily) or matching placebo and followed them for a median of 30 months. The primary efficacy end point was the composite of death from cardiovascular causes, myocardial infarction, or stroke. After 2 years, the data and safety monitoring board recommended discontinuation of the study treatment in patients with a history of stroke owing to the risk of intracranial hemorrhage. RESULTS: At 3 years, the primary end point had occurred in 1028 patients (9.3%) in the vorapaxar group and in 1176 patients (10.5%) in the placebo group (hazard ratio for the vorapaxar group, 0.87; 95% confidence interval [CI], 0.80 to 0.94; P<0.001). Cardiovascular death, myocardial infarction, stroke, or recurrent ischemia leading to revascularization occurred in 1259 patients (11.2%) in the vorapaxar group and 1417 patients (12.4%) in the placebo group (hazard ratio, 0.88; 95% CI, 0.82 to 0.95; P=0.001). Moderate or severe bleeding occurred in 4.2% of patients who received vorapaxar and 2.5% of those who received placebo (hazard ratio, 1.66; 95% CI, 1.43 to 1.93; P<0.001). There was an increase in the rate of intracranial hemorrhage in the vorapaxar group (1.0%, vs. 0.5% in the placebo group; P<0.001). CONCLUSIONS: Inhibition of PAR-1 with vorapaxar reduced the risk of cardiovascular death or ischemic events in patients with stable atherosclerosis who were receiving standard therapy. However, it increased the risk of moderate or severe bleeding, including intracranial hemorrhage. (Funded by Merck; TRA 2P-TIMI 50 ClinicalTrials.gov number, NCT00526474.)