Aportaciones en Ciencias Agronómicas y Ambientales

de investigadores e investigadores independientes. En ese sentido, queremos otorgar un reconocimiento a quienes tuvieron la voluntad y el tino de apoyar esta iniciativa sobre trabajos relacionados con la quimica, biología, agronomía y medio ambiente

Aportaciones en Matemáticas y Química

Presenta una serie de trabajos de investigación sobre el título de este libro: El estudio de fenómenos naturales por medio de datos, trae a colación un conjunto de acciones y procedimientos matemáticos que a veces usamos o abusamos de las restricciones no solo de las técnicas de regresión lineal sino también de las no lineales. para la dieta del mexicano. No obstante, el consumo per cápita se ha reducido de 18 kg a menos de 8.5 kg. Puesto que en las últimas décadas, la producción nacional ha disminuido, entre otras causas debido a la reducción de la superficie agrícola por la urbanización, lo cual margina la producción a regiones con condiciones limitantes para la agricultura; lo no atractivo que ha sido trabajar el campo, los siniestros ocasionados por las condiciones naturales (sequías, inundación, heladas tempranas, etc.) que reducen o hacen nulo el rendimiento. Así como Saber cuánto fertilizante se va a aplicar a un cultivo, ha sido desde la aparición de los fertilizantes artificiales o sales inorgánicas una pregunta que los productores hacen a los técnicos agrícolas. Estos responden usando su experiencia y los resultados de los ya muchísimos experimentos de dosis de nutrimentos de muchos cultivos a la fecha. Se han destacado como importantes para determinar la cantidad de nutrimentos que un cultivo necesita: el tipo de cultivo, las temperaturas, la cantidad de agua disponible (temporal o riego), la textura del suelo y su origen y el contenido de nutrimentos. También otros factores son importantes: la pendiente, la distribución de la precipitación durante el ciclo, la cantidad de luz, etc. Entre otros

VALUE NETWORK OF THE PERSIAN LIME IN MEXICO

Mexico produces the three most important types of lime: Mexican, Persian, andItalian. Persian lime (Citrus latifolia) is the second most important in planted area.Forty-six percent of the production is intended for export. The objective of thisresearch was to analyze the Persian lime value network of the packing andexporting companies. It was conducted at the main Persian lime producing area,located in the central coastal region of the Gulf of Mexico. As an average, thesampled companies were using 55% of their packing capacity. Most of them (83%)work all year long. They have been from 6 to 15 years in operation. Theyemployed a mean of 41 people, thus they are medium-size enterprises. Fourteenactors were complementing their business in production and marketing. Therelationship between packers and the small lime producing farmers was veryinequitable. Low prices were common for Persian lime producers.The fruits theywere packing came mainly from local producers (90%).Their main exportdestinations were: United States, Europe, Canada, and Japan. Other regions areincreasing Persian lime production, threatening the marketing of the farmers of thecentral coast of the Gulf of Mexico

Effects of pre-operative isolation on postoperative pulmonary complications after elective surgery: an international prospective cohort study an international prospective cohort study

We aimed to determine the impact of pre-operative isolation on postoperative pulmonary complications after elective surgery during the global SARS-CoV-2 pandemic. We performed an international prospective cohort study including patients undergoing elective surgery in October 2020. Isolation was defined as the period before surgery during which patients did not leave their house or receive visitors from outside their household. The primary outcome was postoperative pulmonary complications, adjusted in multivariable models for measured confounders. Pre-defined sub-group analyses were performed for the primary outcome. A total of 96,454 patients from 114 countries were included and overall, 26,948 (27.9%) patients isolated before surgery. Postoperative pulmonary complications were recorded in 1947 (2.0%) patients of which 227 (11.7%) were associated with SARS-CoV-2 infection. Patients who isolated pre-operatively were older, had more respiratory comorbidities and were more commonly from areas of high SARS-CoV-2 incidence and high-income countries. Although the overall rates of postoperative pulmonary complications were similar in those that isolated and those that did not (2.1% vs 2.0%, respectively), isolation was associated with higher rates of postoperative pulmonary complications after adjustment (adjusted OR 1.20, 95%CI 1.05–1.36, p = 0.005). Sensitivity analyses revealed no further differences when patients were categorised by: pre-operative testing; use of COVID-19-free pathways; or community SARS-CoV-2 prevalence. The rate of postoperative pulmonary complications increased with periods of isolation longer than 3 days, with an OR (95%CI) at 4–7 days or ≥ 8 days of 1.25 (1.04–1.48), p = 0.015 and 1.31 (1.11–1.55), p = 0.001, respectively. Isolation before elective surgery might be associated with a small but clinically important increased risk of postoperative pulmonary complications. Longer periods of isolation showed no reduction in the risk of postoperative pulmonary complications. These findings have significant implications for global provision of elective surgical care. We aimed to determine the impact of pre-operative isolation on postoperative pulmonary complications after elective surgery during the global SARS-CoV-2 pandemic. We performed an international prospective cohort study including patients undergoing elective surgery in October 2020. Isolation was defined as the period before surgery during which patients did not leave their house or receive visitors from outside their household. The primary outcome was postoperative pulmonary complications, adjusted in multivariable models for measured confounders. Pre-defined sub-group analyses were performed for the primary outcome. A total of 96,454 patients from 114 countries were included and overall, 26,948 (27.9%) patients isolated before surgery. Postoperative pulmonary complications were recorded in 1947 (2.0%) patients of which 227 (11.7%) were associated with SARS-CoV-2 infection. Patients who isolated pre-operatively were older, had more respiratory comorbidities and were more commonly from areas of high SARS-CoV-2 incidence and high-income countries. Although the overall rates of postoperative pulmonary complications were similar in those that isolated and those that did not (2.1% vs 2.0%, respectively), isolation was associated with higher rates of postoperative pulmonary complications after adjustment (adjusted OR 1.20, 95%CI 1.05–1.36, p = 0.005). Sensitivity analyses revealed no further differences when patients were categorised by: pre-operative testing; use of COVID-19-free pathways; or community SARS-CoV-2 prevalence. The rate of postoperative pulmonary complications increased with periods of isolation longer than 3 days, with an OR (95%CI) at 4–7 days or ≥ 8 days of 1.25 (1.04–1.48), p = 0.015 and 1.31 (1.11–1.55), p = 0.001, respectively. Isolation before elective surgery might be associated with a small but clinically important increased risk of postoperative pulmonary complications. Longer periods of isolation showed no reduction in the risk of postoperative pulmonary complications. These findings have significant implications for global provision of elective surgical care