Capability of an optical sensor in verifying the sugarcane response to nitrogen rates

Técnicas de agricultura de precisão são alternativas para otimizar a utilização de insumos, dentre eles o nitrogênio. O presente trabalho teve como objetivo verificar a possibilidade de uso de um sensor ótico ativo comercial na cultura da cana-de-açúcar, verificando sua capacidade em identificar a resposta da cultura a diferentes doses de nitrogênio (N). Para tanto um experimento em blocos ao acaso foi instalado em área experimental de cana-de-açúcar de terceiro corte, colhida mecanicamente, com diferentes doses de N (0, 50, 100, 150 e 200 kg ha-1) e quatro repetições. Aos 30, 60 e 90 dias após o corte (DAC) realizou-se a mensuração do NDVI (índice de vegetação por diferença normalizada) a partir do sensor ótico. Não se obteve resposta do NDVI mensurado aos 30 e 60 DAC, porém aos 90 DAC se verificou que o sensor foi capaz de diferenciar as doses de N aplicadas, correlacionando-se positivamente com a produtividade final de colmos obtida. Este trabalho dá subsídios a trabalhos de mesma natureza que visem a gestão da adubação nitrogenada em cana-de-açúcar a partir de sensores óticos.Techniques of precision agriculture are alternatives to optimize the use of inputs, among them nitrogen. The present work had as its objective to verify the possibility of use of a commercial optical sensor in sugarcane, verifying its capability in identification of the crop response to different nitrogen (N) rates. An experiment was installed in randomized blocks in an experimental area with third sugarcane ratoon, harvested mechanically, with different N rates (0, 50, 100, 150 and 200 kg ha-1) and four repetitions. At 30, 60 and 90 days after the harvest (DAH) the measuring of NDVI (normalized difference vegetation index) was accomplished starting from the optical sensor. No response was verified of NDVI on measurements at the 30 and 60 DAH, however at 90 DAH the sensor was capable to differentiate the doses of applied N, positively correlated with the sugarcane final production. This work gives subsidies to studies of same nature that seek the management of the nitrogen fertilization in sugarcane using optical sensor.FAPES

TEMPORAL BEHAVIOR OF NDVI MEASURED WITH AN ACTIVE OPTICAL SENSOR FOR DIFFERENT VARIETIES OF SUGARCANE / COMPORTAMENTO TEMPORAL DO NDVI MENSURADO COM SENSOR ÓPTICO ATIVO PARA DIFERENTES VARIEDADES DE CANA-DE-AÇÚCAR

Sensores óticos ativos são uma nova opção para o manejo da aplicação localizada de nitrogênio em tempo real e têm sido empregados com sucesso em culturas de grãos. Este trabalho consistiu em avaliar o comportamento do NDVI (Normalized Difference Vegetation Index) obtido com um sensor ótico ativo comercial, em 28 variedades de cana-de-açúcar, assim como analisar o comportamento temporal deste índice para as diferentes variedades ao longo dos primeiros 150 dias de seu ciclo. Os dados do NDVI foram coletados longo dos primeiros 150 dias de seu ciclo. Os dados do NDVI foram coletados aos 90, 120 e 150 dias após o plantio (DAP). Realizou-se análise estatística descritiva dos dados e teste de Tukey para contrastar as médias do NDVI. Os resultados indicaram que as variedades interferem nas leituras do NDVI, assim como, de forma geral, as leituras aos 90 DAP foram diferentes das realizadas aos 120 e 150 DAP, tendendo a se estabilizar ao longo do tempo para cada variedade.</p

Evaluation of a quality improvement intervention to reduce anastomotic leak following right colectomy (EAGLE): pragmatic, batched stepped-wedge, cluster-randomized trial in 64 countries

Background Anastomotic leak affects 8 per cent of patients after right colectomy with a 10-fold increased risk of postoperative death. The EAGLE study aimed to develop and test whether an international, standardized quality improvement intervention could reduce anastomotic leaks. Methods The internationally intended protocol, iteratively co-developed by a multistage Delphi process, comprised an online educational module introducing risk stratification, an intraoperative checklist, and harmonized surgical techniques. Clusters (hospital teams) were randomized to one of three arms with varied sequences of intervention/data collection by a derived stepped-wedge batch design (at least 18 hospital teams per batch). Patients were blinded to the study allocation. Low- and middle-income country enrolment was encouraged. The primary outcome (assessed by intention to treat) was anastomotic leak rate, and subgroup analyses by module completion (at least 80 per cent of surgeons, high engagement; less than 50 per cent, low engagement) were preplanned. Results A total 355 hospital teams registered, with 332 from 64 countries (39.2 per cent low and middle income) included in the final analysis. The online modules were completed by half of the surgeons (2143 of 4411). The primary analysis included 3039 of the 3268 patients recruited (206 patients had no anastomosis and 23 were lost to follow-up), with anastomotic leaks arising before and after the intervention in 10.1 and 9.6 per cent respectively (adjusted OR 0.87, 95 per cent c.i. 0.59 to 1.30; P = 0.498). The proportion of surgeons completing the educational modules was an influence: the leak rate decreased from 12.2 per cent (61 of 500) before intervention to 5.1 per cent (24 of 473) after intervention in high-engagement centres (adjusted OR 0.36, 0.20 to 0.64; P &lt; 0.001), but this was not observed in low-engagement hospitals (8.3 per cent (59 of 714) and 13.8 per cent (61 of 443) respectively; adjusted OR 2.09, 1.31 to 3.31). Conclusion Completion of globally available digital training by engaged teams can alter anastomotic leak rates. Registration number: NCT04270721 (http://www.clinicaltrials.gov)