Técnica de muestreo y preparación del material para análisis foliar

Una de las técnicas para determinar el estado nutricional de la planta es el análisis foliar, es decir, el análisis químico de la planta misma. En todo análisis de tejido vegetal, una de las etapas más importantes es la toma y preparación de la muestra que va a ser sometida al proceso químico de análisis

Disponibilidad del azufre para las plantas en dos suelos de los Llanos Orientales de Colombia.

Trabajo para estudiar la influencia de 2 fuentes marcadas y varios niveles de S sobre el rendimiento de materia seca y absorción y utilización de varios macro y micronutrimentos por el pasto raigrás anual (Lolium multiflorum) bajo condiciones de invernadero en dos suelos de los Llanos Orientales. Determinar la correlación de 2 métodos de extracción de S del suelo. Determinar el valor A por medio del uso del radioisótopo S35. Determinar la distribución del S dentro de la planta utilizando técnica del radio-isótopo. Observar la influencia sobre el pH y contenido de P en el suelo de 2 fuentes y varios niveles de S. En el Centro de Investigaciones Tibaitatá, se aplicaron con 4 replicaciones cada uno, niveles de 0-25-50-75-100-125-150 kg/ha de S (NH4)2SO4 y 0-50-100-150 kg/ha de S en forma de CaSO4, ambas fuentes marcadas con S35. Se encaló antes de la siembra. Se determinó el contenido de P disponible por Bray II en cada uno de los potes de 1800 gr de suelo y pH después del segundo corte, se encontró que el pH disminuía a medida que aumentaba la cantidad de S, siendo más marcada la acción del (NH4)2SO4 en suelo de La Libertad. Mediante el uso del S35 se halló el valor A, que es un índice de la disponibilidad del S del suelo. Los testigos mostraron sintomatología característica de deficiencia de

Comparación de resultados de análisis de suelos y tejido foliar de plantas ornamentales realizados en Estados Unidos y en Colombia (ICA).

Deducir ecuaciones de conversión de los resultados obtenidos en el ICA y en los Estados Unidos y viceversa. El trabajo fue realizado en el Laboratorio del Programa de suelos del ICA, (Tibaitatá), con duración de 18 meses. Se utilizaron 200 muestras de suelo provenientes de la Sabana de Bogotá y 150 muestras de tejido foliar de plantas ornamentales (clavel en su mayoría, pompón y rosas) suministradas por Asocoflores, las cuales fueron analizadas químicamente en Estados Unidos (Plant and Soil Laboratory y Dr. Wolfs Agricultural Laboratories) y, en el Laboratorio del Programa de Suelos del ICA, Tibaitatá. Se hizo un estudio comparativo de los análisis realizados en ICA y Estados Unidos, obteniendose una correlación altamente significativa y un elevado grado de asociación para las distintas determinaciones efectuadas en muestras de suelos y plantas. Fue posible deducir ecuaciones para encontrar la equivalencia entre los resultados de los análisis obtenidos en el ICA y los resultados de los laboratorios de Estados Unidos y viceversa. Los factores de conversión en las mencionadas ecuaciones fueron cercanos a 1 para la mayoría de las variables, lo cual mostró que la diferencia entre resultados fué pequeñaFlores y ornamentale

Determinación de nitrógeno, fósforo, potasio, calcio y magnesio en muestras vegetales usando una sola digestión.

Se busca un método que permita en una sola digestión determinar en muestras vegetales la concentración de N, P, K, Ca, Mg. El método convencional, en el cual el N se determinó por el método micro-kjeldahl, haciendo una digestión separada. El método propuesto en el cual se utilizó una sola digestión para la determinación de N-P-K-Ca-Mg usando ácido sulfúrico y como catalizador una mezcla de 0.8 gr de Se en polvo y 40 g de sulfato de Na. Los resultados mostraron que existe interferencia del Se sobre el Ca, la cual se obvía agregando 100 ppm de Se a los patrones. Se encontraron coeficientes de correlación positivas altamente significativas entre los dos métodos estudiados. No hubo interferencia del Se sobre el K determinado por absorción y emisión. El error de los métodos estudiados en relación al contenido de nutrimentos de las muestras patrón y conocidas fué inferior al 10 por ciento. La relación entre los métodos utilzados y las muestras conocidas mostró coeficientes positivos significativos al nivel de probabilidad de error del 1 por ciento. Los resultados indican que ambos métodos detectan en forma confiable los elementos N-P-K-Ca-Mg. El método propuesto además de confiable, tiene la ventaja de ahorrar tiempo, reactivos, y evita el uso de ácido perclórico

El análisis de suelos y las recomendaciones de fertilizantes y cal: tercera aproximación

Recomendaciones para fertilización de varios cultivos teniendo como guía el análisis de suelos. Se consideran los siguientes aspectos : elementos menores, encalamiento, niveles críticos de P y K, factores que afectan la eficiencia de la fertilización y costo de la misma. Se incluyen 17 tablas sobre aplicación de fertilizantes para cultivos como algodón, arroz, hortalizas, papa, leguminosas de grano, leguminosas anuales : ajonjolí, maní, para pastos establecidos y por establecer. Además, para cultivos de trigo, cebada, avena y trigo para grano. Se anexa una eplicación sobre métodos de análisis de suelo

Hyperoxemia and excess oxygen use in early acute respiratory distress syndrome : Insights from the LUNG SAFE study

Publisher Copyright: © 2020 The Author(s). Copyright: Copyright 2020 Elsevier B.V., All rights reserved.Background: Concerns exist regarding the prevalence and impact of unnecessary oxygen use in patients with acute respiratory distress syndrome (ARDS). We examined this issue in patients with ARDS enrolled in the Large observational study to UNderstand the Global impact of Severe Acute respiratory FailurE (LUNG SAFE) study. Methods: In this secondary analysis of the LUNG SAFE study, we wished to determine the prevalence and the outcomes associated with hyperoxemia on day 1, sustained hyperoxemia, and excessive oxygen use in patients with early ARDS. Patients who fulfilled criteria of ARDS on day 1 and day 2 of acute hypoxemic respiratory failure were categorized based on the presence of hyperoxemia (PaO2 > 100 mmHg) on day 1, sustained (i.e., present on day 1 and day 2) hyperoxemia, or excessive oxygen use (FIO2 ≥ 0.60 during hyperoxemia). Results: Of 2005 patients that met the inclusion criteria, 131 (6.5%) were hypoxemic (PaO2 < 55 mmHg), 607 (30%) had hyperoxemia on day 1, and 250 (12%) had sustained hyperoxemia. Excess FIO2 use occurred in 400 (66%) out of 607 patients with hyperoxemia. Excess FIO2 use decreased from day 1 to day 2 of ARDS, with most hyperoxemic patients on day 2 receiving relatively low FIO2. Multivariate analyses found no independent relationship between day 1 hyperoxemia, sustained hyperoxemia, or excess FIO2 use and adverse clinical outcomes. Mortality was 42% in patients with excess FIO2 use, compared to 39% in a propensity-matched sample of normoxemic (PaO2 55-100 mmHg) patients (P = 0.47). Conclusions: Hyperoxemia and excess oxygen use are both prevalent in early ARDS but are most often non-sustained. No relationship was found between hyperoxemia or excessive oxygen use and patient outcome in this cohort. Trial registration: LUNG-SAFE is registered with ClinicalTrials.gov, NCT02010073publishersversionPeer reviewe

Design and baseline characteristics of the finerenone in reducing cardiovascular mortality and morbidity in diabetic kidney disease trial

Background: Among people with diabetes, those with kidney disease have exceptionally high rates of cardiovascular (CV) morbidity and mortality and progression of their underlying kidney disease. Finerenone is a novel, nonsteroidal, selective mineralocorticoid receptor antagonist that has shown to reduce albuminuria in type 2 diabetes (T2D) patients with chronic kidney disease (CKD) while revealing only a low risk of hyperkalemia. However, the effect of finerenone on CV and renal outcomes has not yet been investigated in long-term trials. Patients and Methods: The Finerenone in Reducing CV Mortality and Morbidity in Diabetic Kidney Disease (FIGARO-DKD) trial aims to assess the efficacy and safety of finerenone compared to placebo at reducing clinically important CV and renal outcomes in T2D patients with CKD. FIGARO-DKD is a randomized, double-blind, placebo-controlled, parallel-group, event-driven trial running in 47 countries with an expected duration of approximately 6 years. FIGARO-DKD randomized 7,437 patients with an estimated glomerular filtration rate >= 25 mL/min/1.73 m(2) and albuminuria (urinary albumin-to-creatinine ratio >= 30 to <= 5,000 mg/g). The study has at least 90% power to detect a 20% reduction in the risk of the primary outcome (overall two-sided significance level alpha = 0.05), the composite of time to first occurrence of CV death, nonfatal myocardial infarction, nonfatal stroke, or hospitalization for heart failure. Conclusions: FIGARO-DKD will determine whether an optimally treated cohort of T2D patients with CKD at high risk of CV and renal events will experience cardiorenal benefits with the addition of finerenone to their treatment regimen. Trial Registration: EudraCT number: 2015-000950-39; ClinicalTrials.gov identifier: NCT02545049

Outcomes from elective colorectal cancer surgery during the SARS-CoV-2 pandemic

This study aimed to describe the change in surgical practice and the impact of SARS-CoV-2 on mortality after surgical resection of colorectal cancer during the initial phases of the SARS-CoV-2 pandemic

Elective cancer surgery in COVID-19-free surgical pathways during the SARS-CoV-2 pandemic: An international, multicenter, comparative cohort study

PURPOSE As cancer surgery restarts after the first COVID-19 wave, health care providers urgently require data to determine where elective surgery is best performed. This study aimed to determine whether COVID-19–free surgical pathways were associated with lower postoperative pulmonary complication rates compared with hospitals with no defined pathway. PATIENTS AND METHODS This international, multicenter cohort study included patients who underwent elective surgery for 10 solid cancer types without preoperative suspicion of SARS-CoV-2. Participating hospitals included patients from local emergence of SARS-CoV-2 until April 19, 2020. At the time of surgery, hospitals were defined as having a COVID-19–free surgical pathway (complete segregation of the operating theater, critical care, and inpatient ward areas) or no defined pathway (incomplete or no segregation, areas shared with patients with COVID-19). The primary outcome was 30-day postoperative pulmonary complications (pneumonia, acute respiratory distress syndrome, unexpected ventilation). RESULTS Of 9,171 patients from 447 hospitals in 55 countries, 2,481 were operated on in COVID-19–free surgical pathways. Patients who underwent surgery within COVID-19–free surgical pathways were younger with fewer comorbidities than those in hospitals with no defined pathway but with similar proportions of major surgery. After adjustment, pulmonary complication rates were lower with COVID-19–free surgical pathways (2.2% v 4.9%; adjusted odds ratio [aOR], 0.62; 95% CI, 0.44 to 0.86). This was consistent in sensitivity analyses for low-risk patients (American Society of Anesthesiologists grade 1/2), propensity score–matched models, and patients with negative SARS-CoV-2 preoperative tests. The postoperative SARS-CoV-2 infection rate was also lower in COVID-19–free surgical pathways (2.1% v 3.6%; aOR, 0.53; 95% CI, 0.36 to 0.76). CONCLUSION Within available resources, dedicated COVID-19–free surgical pathways should be established to provide safe elective cancer surgery during current and before future SARS-CoV-2 outbreaks

Elective Cancer Surgery in COVID-19-Free Surgical Pathways During the SARS-CoV-2 Pandemic: An International, Multicenter, Comparative Cohort Study.

PURPOSE: As cancer surgery restarts after the first COVID-19 wave, health care providers urgently require data to determine where elective surgery is best performed. This study aimed to determine whether COVID-19-free surgical pathways were associated with lower postoperative pulmonary complication rates compared with hospitals with no defined pathway. PATIENTS AND METHODS: This international, multicenter cohort study included patients who underwent elective surgery for 10 solid cancer types without preoperative suspicion of SARS-CoV-2. Participating hospitals included patients from local emergence of SARS-CoV-2 until April 19, 2020. At the time of surgery, hospitals were defined as having a COVID-19-free surgical pathway (complete segregation of the operating theater, critical care, and inpatient ward areas) or no defined pathway (incomplete or no segregation, areas shared with patients with COVID-19). The primary outcome was 30-day postoperative pulmonary complications (pneumonia, acute respiratory distress syndrome, unexpected ventilation). RESULTS: Of 9,171 patients from 447 hospitals in 55 countries, 2,481 were operated on in COVID-19-free surgical pathways. Patients who underwent surgery within COVID-19-free surgical pathways were younger with fewer comorbidities than those in hospitals with no defined pathway but with similar proportions of major surgery. After adjustment, pulmonary complication rates were lower with COVID-19-free surgical pathways (2.2% v 4.9%; adjusted odds ratio [aOR], 0.62; 95% CI, 0.44 to 0.86). This was consistent in sensitivity analyses for low-risk patients (American Society of Anesthesiologists grade 1/2), propensity score-matched models, and patients with negative SARS-CoV-2 preoperative tests. The postoperative SARS-CoV-2 infection rate was also lower in COVID-19-free surgical pathways (2.1% v 3.6%; aOR, 0.53; 95% CI, 0.36 to 0.76). CONCLUSION: Within available resources, dedicated COVID-19-free surgical pathways should be established to provide safe elective cancer surgery during current and before future SARS-CoV-2 outbreaks