Abstract Background: Elderly patients are more susceptible to Coronavirus Disease-2019 (COVID-19) and are more likely to develop it in severe forms, (e.g., Acute Respiratory Distress Syndrome [ARDS]). Prone positioning is a treatment strategy for severe ARDS; however, its response in the elderly population remains poorly understood. The main objective was to evaluate the predictive response and mortality of elderly patients exposed to prone positioning due to ARDS-COVID-19. Methods: This retrospective multicenter cohort study involved 223 patients aged ≥ 65 years, who received prone position sessions for severe ARDS due to COVID-19, using invasive mechanical ventilation. The PaO2/FiO2 ratio was used to assess the oxygenation response. The 20-point improvement in PaO2/FiO2 after the first prone session was considered for good response. Data were collected from electronic medical records, including demographic data, laboratory/image exams, complications, comorbidities, SAPS III and SOFA scores, use of anticoagulants and vasopressors, ventilator settings, and respiratory system mechanics. Mortality was defined as deaths that occurred until hospital discharge. Results: Most patients were male, with arterial hypertension and diabetes mellitus as the most prevalent comorbidities. The non-responders group had higher SAPS III and SOFA scores, and a higher incidence of complications. There was no difference in mortality rate. A lower SAPS III score was a predictor of oxygenation response, and the male sex was a risk predictor of mortality. Conclusion: The present study suggests the oxygenation response to prone positioning in elderly patients with severe COVID-19-ARDS correlates with the SAPS III score. Furthermore, the male sex is a risk predictor of mortality. Background Disease2019 Disease 2019 Disease-201 COVID19 COVID 19 (COVID-19 forms e.g., eg e g (e.g. ARDS. . [ARDS]) however understood ARDSCOVID19. ARDSCOVID19 ARDSCOVID 19. ARDS-COVID-19 Methods 22 6 years COVID19, 19, COVID-19 ventilation PaO2FiO2 PaOFiO PaO2 FiO2 PaO FiO PaO2/FiO 20point point 20 records data laboratoryimage laboratory image exams complications comorbidities scores vasopressors settings mechanics discharge Results nonresponders non responders rate Conclusion COVID19ARDS COVIDARDS Furthermore Disease201 201 Disease-20 COVID1 1 (COVID-1 e.g. (e.g [ARDS] ARDSCOVID1 ARDS-COVID-1 2 COVID-1 PaO2FiO Disease20 Disease-2 (COVID- e.g [ARDS ARDS-COVID- COVID- Disease2 Disease- (COVID ARDS-COVID

RESUMO Objetivo: Identificar fatores que levam a uma resposta positiva da oxigenação e fatores preditivos de mortalidade após a pronação. Métodos: Estudo de coorte retrospectivo multicêntrico envolvendo sete hospitais brasileiros. Os critérios de inclusão foram idade > 18 anos com diagnóstico suspeito ou confirmado de COVID-19, ventilação mecânica invasiva, relação PaO2/FIO2 < 150 mmHg e pronação. Após a primeira sessão de pronação, uma melhora de 20 mmHg na relação PaO2/FIO2 foi definida como resposta positiva. Resultados: O estudo envolveu 574 pacientes, dos quais 412 (72%) apresentaram resposta positiva à primeira sessão de pronação. A regressão logística múltipla mostrou que os respondedores apresentaram menores pontuações no Simplified Acute Physiology Score III (SAPS III) e no SOFA e menores níveis de dímero D (p = 0,01; p = 0,04; e p = 0,04, respectivamente). Sugeriu-se que a pontuação no SAPS III e a PaO2/FIO2 iniciais seriam preditores da resposta da oxigenação. A taxa de mortalidade foi de 69,3%. Maior risco de mortalidade foi associado à idade (OR = 1,04 [IC95%: 1,01-1,06]), tempo até a primeira sessão de pronação (OR = 1,18 [IC95%: 1,06-1,31]), número de sessões (OR = 1,31 [IC95%: 1,00-1,72]), porcentagem de comprometimento pulmonar (OR = 1,55 [IC95%: 1,02-2,35]) e imunossupressão (OR = 3,83 [IC95%: 1,35-10,86]). Conclusões: Nossos resultados mostram que a maioria dos pacientes de nossa amostra apresentou resposta positiva da oxigenação após a primeira sessão de pronação. No entanto, a taxa de mortalidade foi elevada, provavelmente em virtude do estado de saúde e número de comorbidades dos pacientes e da gravidade de sua doença. Nossos resultados também sugerem que a pontuação no SAPS III e a PaO2/FIO2 inicial predizem a resposta da oxigenação; além disso, idade, tempo até a primeira sessão de pronação, número de sessões, comprometimento pulmonar e imunossupressão podem predizer mortalidade.

ABSTRACT Objective: To identify factors that lead to a positive oxygenation response and predictive factors of mortality after prone positioning. Methods: This was a retrospective, multicenter, cohort study involving seven hospitals in Brazil. Inclusion criteria were being > 18 years of age with a suspected or confirmed diagnosis of COVID-19, being on invasive mechanical ventilation, having a PaO2/FIO2 ratio < 150 mmHg, and being submitted to prone positioning. After the first prone positioning session, a 20 mmHg improvement in the PaO2/FIO2 ratio was defined as a positive response. Results: The study involved 574 patients, 412 (72%) of whom responded positively to the first prone positioning session. Multiple logistic regression showed that responders had lower Simplified Acute Physiology Score III (SAPS III)/SOFA scores and lower D-dimer levels (p = 0.01; p = 0.04; and p = 0.04, respectively). It was suggested that initial SAPS III and initial PaO2/FIO2 were predictors of oxygenation response. The mortality rate was 69.3%. Increased risk of mortality was associated with age (OR = 1.04 [95 CI: 1.01-1.06]), time to first prone positioning session (OR = 1.18 [95 CI: 1.06-1.31]), number of sessions (OR = 1.31 [95% CI: 1.00-1.72]), proportion of pulmonary impairment (OR = 1.55 [95% CI: 1.02-2.35]), and immunosuppression (OR = 3.83 [95% CI: 1.35-10.86]). Conclusions: Our results show that most patients in our sample had a positive oxygenation response after the first prone positioning session. However, the mortality rate was high, probably due to the health status and the number of comorbidities of the patients, as well as the severity of their disease. Our results also suggest that SAPS III and the initial PaO2/FIO2 predict the oxygenation response; in addition, age, time to first prone positioning, number of sessions, pulmonary impairment, and immunosuppression can predict mortality.

Abstract Background Goosegrass is one of the most troublesome weed species in Brazil due to its wide dispersion and the ability to evolve herbicide resistance. Objective Investigate the response of goosegrass accessions from Mato Grosso, Brazil to glyphosate, clethodim, and haloxyfop. Methods Goosegrass seed samples were collected from seventeen production fields (accessions) in Mato Grosso and screened with the recommended label rates of clethodim, haloxyfop-methyl, and glyphosate. Six accessions withstood the label rate of the evaluated herbicides and were subjected to a dose-response study. Out of the six accessions, two were selected for further F1 dose-response investigations due to their ability to survive the label rate of the three herbicides individually. All studies were conducted under greenhouse conditions in a completely randomized design with four replications, and the F1 dose-response study was replicated in time. Results All six accessions investigated in the dose-response study presented ED50 values higher than susceptible plants for control and biomass reduction. Haloxyfop-methyl had the highest resistance ratios, followed by clethodim and glyphosate. The two accessions investigated in the F1 dose-response study were confirmed to be cross-resistant to clethodim and haloxyfop-methyl and showed low-level resistance to glyphosate. Conclusions The continuous reliance of POST herbicides for weed management in Mato Grosso cropping systems has selected goosegrass accessions that can withstand high rates of ACCase-inhibiting herbicides, particularly haloxyfop-methyl. Moreover, two accessions with resistance to ACCase-inhibiting herbicides, clethodim and haloxyfop-methyl, and low-level resistance to glyphosate were identified, suggesting the presence of multiple resistance in goosegrass accessions from Mato Grosso, Brazil.

RESUMO: Este trabalho teve por objetivo avaliar a fitossociologia de plantas daninhas em arroz irrigado em diferentes sistemas de manejo do solo e intensidade de rotação de culturas. Para tanto, foram conduzidos dois estudos de campo. O primeiro estudo foi realizado em área cultivada desde 1994 com três sistemas de cultivo: plantio direto, pré-germinado e sistema convencional. O segundo estudo foi realizado em área experimental sob cinco Sistemas Integrados de Produção Agropecuária, com rotação de culturas. As avaliações fitossociológicas foram realizadas quando o arroz estava em pleno florescimento no primeiro estudo, e no final do enchimento de grãos no segundo. O sistema pré-germinado de cultivo de arroz apresenta predominância de plantas daninhas aquáticas. O sistema de cultivo convencional, quando comparado ao plantio direto, possui menores densidades de plantas daninhas. Nos Sistemas Integrados de Produção Agropecuária com maior intensidade de rotação de culturas houve maior infestação de plantas daninhas perenes.

ABSTRACT: This research aimed to evaluate the phytosociology of weeds in irrigated rice in different soil management systems and crop rotation intensity. Therefore, two field studies were carried out. Study 1 was conducted in an area that has been cultivated since 1994 with three cultivation systems: direct, pre-germinated and conventional ones. Study 2 was carried out in an experimental area in five Integrated Farming Systems, with crop rotation. Phytosociological evaluations were conducted when rice was fully blooming, in the first study, and when grain filling was ending, in the second study. Pre-germinated system of rice cultivation has predominance of aquatic weeds. Conventional system when compared with direct sowing has lower weed densities. Integrated Agricultural Production Systems with higher intensity of crop rotation have been higher infested of perennial species.

Espécies com via fotossintética C4 são mais eficientes na assimilação de N que plantas C3, o que resulta em diferentes resistências do N do tecido à possibilidade de lavagem por chuva. Essa diferença pode alterar a ciclagem de N em sistemas agrícolas onde essas espécies são utilizadas como plantas de cobertura. O presente trabalho teve como objetivo estudar a produção de fitomassa em resposta ao N e à lavagem do nutriente da palha de gramíneas com diferentes vias de assimilação de carbono. Milheto (Pennisetum glaucum) e braquiária (Brachiaria ruziziensis), com via C4, e aveia-preta (Avena strigosa) e triticale (X. Triticosecale), com via C3 de assimilação de C, foram cultivados por 47 dias. Foi determinada a produção de matéria seca e tomadas amostras para determinação de N e C no tecido. Em seguida, foi simulada uma chuva de 30 mm, aplicada sobre o equivalente a 8 t ha-1 de matéria seca de resíduos. Foram determinadas as quantidades de amônio e nitrato lavadas dos resíduos. As gramíneas C4 responderam a doses mais altas de fertilizante, mas os teores de N no tecido foram menores. A quantidade de N lavada dos resíduos foi menor para as plantas C4 provavelmente porque sua relação C/N foi maior e o N estava mais fortemente ligado aos compostos orgânicos da planta. No planejamento de uma rotação de culturas é importante ter em conta as diferenças na liberação de N dos resíduos, uma vez que isso pode alterar a nutrição nitrogenada da próxima cultura.

Crop species with the C4 photosynthetic pathway are more efficient in assimilating N than C3 plants, which results in different N amounts prone to be washed from its straw by rain water. Such differences may affect N recycling in agricultural systems where these species are grown as cover crops. In this experiment, phytomass production and N leaching from the straw of grasses with different photosynthetic pathways were studied in response to N application. Pearl millet (Pennisetum glaucum) and congo grass (Brachiaria ruziziensis) with the C4 photosynthetic pathway, and black oat (Avena Strigosa) and triticale (X Triticosecale), with the C3 photosynthetic pathway, were grown for 47 days. After determining dry matter yields and N and C contents, a 30 mm rainfall was simulated over 8 t ha-1 of dry matter of each plant residue and the leached amounts of ammonium and nitrate were determined. C4 grasses responded to higher fertilizer rates, whereas N contents in plant tissue were lower. The amount of N leached from C4 grass residues was lower, probably because the C/N ratio is higher and N is more tightly bound to organic compounds. When planning a crop rotation system it is important to take into account the difference in N release of different plant residues which may affect N nutrition of the subsequent crop.

O manejo correto da adubação potássica pode minimizar perdas assim como evitar o esgotamento de K do solo. Objetivou-se estudar a dinâmica do K no perfil do solo em função do teor de argila e do teor do nutriente resultantes da adubação da soja. Foram coletados solos de texturas média e argilosa, que vinham sendo adubados com 0, 60, 120, e 180 kg ha-1 de K2O na soja por 6 anos. O experimento foi conduzido em casa de vegetação, em tubos de PVC estratificados nas profundidades de 0-5, 5-10, 10-20, e 20-40 cm. Na superfície das colunas, aplicaram-se mais 80 kg ha-1 de K2O. Durante 16 semanas, foi aplicada, semanalmente, água em quantidade equivalente a 100 mm de chuva. Em cada aplicação, o volume de solução percolada foi determinado, assim como as quantidades de K contidas nessa solução. Após a desmontagem das colunas de solo, foram determinados os teores de K trocável e não-trocável nas diferentes profundidades. A percolação de K foi maior no solo de textura argilosa, que tinha mais K disponível devido ao maior efeito residual da adubação potássica anterior. A intensidade de lixiviação foi proporcional ao teor de K disponível, mas inicialmente a lixiviação foi mais intensa no solo mais arenoso, decrescendo com o tempo. No argiloso, as perdas foram mais constantes. Houve proporcionalidade entre teor inicial e lixiviação no perfil do solo, nas duas formas de K e nos dois tipos de solo. Conclui-se que o efeito residual da adubação potássica aumentou as quantidades de K percolado. A movimentação de K no perfil do solo teve boa relação com o teor inicial de K no solo, resultante da adubação potássica anterior nos dois tipos de solo. A passagem de K considerado não-trocável para trocável foi rápida e influenciou na lixiviação.

A correct potassium fertilization management, using adequate fertilizer amounts, can minimize K losses and avoid soil K depletion. The objective of this study was to evaluate potassium dynamics in the soil profile as affected by different textures and exchangeable K levels resulting from previous soybean fertilizations. Soils with sandy loam and clayey texture previously planted with soybean and fertilized with 0, 60, 120 and 180 kg ha-1 K2O were sampled during 6 years. The experiment was carried out in a greenhouse, using 40 cm high and 5 cm diameter PVC tubes, where it was stratified the 0-5, 5-10, 10-20 and 20-40 cm soil layers. On the column surface, 80 kg ha-1 of K2O was applied as KCl and 100 mm water was applied weekly, for 16 weeks. At each application, the drainage solution volume and the K concentration in the leacheate were determined. After the disassembly of the soil columns, exchangeable and non-exchangeable K contents were determined for each layer. Potassium leaching was higher in the clay soil, where available K was higher due to the residual effect of previous K fertilization. Leaching intensity was proportional to available K contents. In the sandy soil initial leaching intensity was higher but decreased along time, whereas in the clayey soil K losses were more constant. The soil K level and leaching in soil profile were proportional to the exchangeable and non-exchangeable K for both soils. The residual effect of K fertilizer during the years under soybean, increasing its availability, can result in intensive exchangeable K losses, irrespective of soil texture. Potassium transformation from non exchangeable to exchangeable K is very fast, and affects the amount of leached K.