Mejoramiento del porcentaje de proteina en maiz para ensilaje con el aumento y parcializaci 3n de la fertilizacion nitrogenada

In clay soils with poor drainage two trials were carried out with the objective of determining the effect of nitrogen application on maize (Zea mays L.) for silage on forage yield and protein content. In Trial 1, the treatments were two corn silage hybrids of different growing periods, SX-43 and INIA-150, sown at 90.000 plants ha-1 and four N rates: 0, 100, 200 and 400 kg N ha-1. In Trial 2, the treatments were two N rates: 200 and 400 kg of N ha-1, and three forms of N application: a) 1/2 at sowing + 1/2 at 30 cm plant height; b) 1/3 at sowing + 1/3 at 30 cm plant height + 1/3 at 60 cm plant height; and c) 1/4 at sowing + 1/4 at 30 cm plant height + 1/4 at 60 cm plant height +1/4 at flowering. One treatment was without N. In Trial 1 N application increased DM yield (P < 0.05), but no significant response was observed with N rates between 100 and 400 kg N ha-1, due to soil limitations. Forage production and protein percentage increased significantly with N application. In Trial 2, DM production in corn silage increased with higher N rates (P < 0.05). Forage protein percentage was increased by higher N rates and partitioning of the application. On increasing the partitioning of N from two to four applications, protein percentage of forage was increased by 23 and 37% for 200 and 400 kg of N ha-1, respectively.En suelos arcillosos de mal drenaje se realizaron dos ensayos con el objetivo de determinar la respuesta de ma\uedz (Zea mays L.) para ensilaje a la aplicaci\uf3n de N en el rendimiento y contenido de prote\uedna del forraje. En el Ensayo 1 los tratamientos correspondieron a dos h\uedbridos de ma\uedz para ensilaje de distinta precocidad, SX-43 e INIA-150, sembrados con una poblaci\uf3n de 90.000 plantas ha-1 y cuatro dosis de N: 0, 100, 200 y 400 kg N ha-1. En el Ensayo 2, los tratamientos fueron dos dosis de N: 200 y 400 kg N ha-1, y tres formas de aplicaci\uf3n de nitr\uf3geno: a) 1/2 a la siembra + 1/2 a 30 cm de altura de las plantas; b) 1/3 a la siembra + 1/3 a 30 cm de altura de las plantas + 1/3 a 60 cm de altura de plantas; y c) 1/4 a la siembra + 1/4 a 30 cm de altura de las plantas + 1/4 a 60 cm de altura de plantas +1/4 en floraci\uf3n. Adem\ue1s se incluy\uf3 un tratamiento sin aplicaci\uf3n de N. En el Ensayo 1, la aplicaci\uf3n de N aument\uf3 el rendimiento de MS (P < 0,05), sin embargo no hubo respuesta significativa entre 100 y 400 kg de N, debido a limitantes de suelo. La producci\uf3n y el porcentaje de prote\uedna del forraje aument\uf3 significativamente con la aplicaci\uf3n de N. En el Ensayo 2, la producci\uf3n de MS en el ma\uedz aument\uf3 con la aplicaci\uf3n de N (P < 0,05). El porcentaje de prote\uedna del forraje se increment\uf3 con mayores dosis de N y su parcializaci\uf3n. Al aumentar la parcializaci\uf3n del N de 2 a 4 aplicaciones se increment\uf3 el tenor proteico del forraje en 23 y 37 % para las dosis de 200 y 400 kg N ha-1, respectivamente

Especies leguminosas forrajeras para corte en suelos arcillosos de mal drenaje

Forage yield of three species of leguminous forrages: alfalfa, Medicago sativa L.; red clover, Trifolium pratense L.; and birdsfoot trefoil Lotus corniculatus L. was evaluated in waterlogged soils in the VIIth Region, Chile, during four seasons with three fertilization rates: 2 t lime ha-1 + 150 kg P2O5 ha-1; no lime application + 150 kg P2O5 ha-1; and no lime + 70 kg of P2O5 ha-1, applying half of the fertilizer dose during the seasons following establishment. The experimental design was randomized complete blocks with four repetitions. An analysis of variance was carried out and means were compared using the Duncan test (P 64 0.05). Alfalfa needed high fertilization to achieve production comparable to birdsfoot trefoil and red clover, reaching its best production with complete fertilization in the first season (4.6 t DM ha-1). The red clover maintained high production until the second season independent of the fertilizer dose (11.8 t DM ha-1), but began to decline in the third season. The birdsfoot trefoil was the species best adapted to these soil conditions, DM yield was not affected by the dose of phosphorus in the four years, reaching production levels of 7.1 t DM ha-1 during the fourth season.Se evalu\uf3 el rendimiento de forraje en tres especies de leguminosas forrajeras: alfalfa, Medicago sativa L.; tr\ue9bol rosado, Trifolium pratense L.; y lotera, Lotus corniculatus L. en suelos arcillosos de mal drenaje de la VII Regi\uf3n, Chile, durante cuatro temporadas, con tres niveles de fertlizaci\uf3n: 2 t de cal ha-1 + 150 kg de P2O5 ha-1; sin aplicaci\uf3n de cal + 150 kg de P2O5 ha-1; y sin cal + 70 kg de P2O5 ha-1, aplicando durante las siguientes temporadas la mitad de la dosis de fertilizante aplicado al establecimiento. El dise\uf1o experimental utilizado fue de bloques completos al azar con cuatro repeticiones. Se realiz\uf3 an\ue1lisis de varianza y en la comparaci\uf3n de medias se us\uf3 la prueba de Duncan (P 64 0,05). La alfalfa necesit\uf3 una alta fertilizaci\uf3n para lograr una producci\uf3n comparable a la lograda por la lotera y tr\ue9bol rosado, alcanzando su mayor producci\uf3n con fertilizaci\uf3n completa en la primera temporada (4,6 t MS ha-1). El tr\ue9bol rosado mantuvo una alta producci\uf3n hasta la segunda temporada independiente de la dosis de fertilizante (11,8 t MS ha-1), la que empez\uf3 a declinar en la tercera temporada. La lotera fue la especie que mejor se adapt\uf3 a estas condiciones de suelo, no se afect\uf3 su rendimiento de MS por la dosis de P en los cuatro a\uf1os, alcanzando niveles de producci\uf3n de 7,1 t MS ha-1 durante la cuarta temporada

Enfermedades crónicas

Adherencia al tratamiento farmacológico y relación con el control metabólico en pacientes con DM2Aluminio en pacientes con terapia de reemplazo renal crónico con hemodiálisis en Bogotá, ColombiaAmputación de extremidades inferiores: ¿están aumentando las tasas?Consumo de edulcorantes artificiales en jóvenes universitariosCómo crecen niños normales de 2 años que son sobrepeso a los 7 añosDiagnóstico con enfoque territorial de salud cardiovascular en la Región MetropolitanaEfecto a corto plazo de una intervención con ejercicio físico, en niños con sobrepesoEfectos de la cirugía bariátrica en pacientes con síndrome metabólico e IMC < 35 KG/M2Encuesta mundial de tabaquismo en estudiantes de profesiones de saludEnfermedades crónicas no transmisibles: Consecuencias sociales-sanitarias de comunidades rurales en ChileEpidemiología de las muertes hospitalarias por patologías relacionadas a muerte encefálica, Chile 2003-2007Estado nutricional y conductas alimentarias en adolescentes de 4º medio de la Región de CoquimboEstudio de calidad de vida en una muestra del plan piloto para hepatitis CEvaluación del proceso asistencial y de resultados de salud del GES de diabetes mellitus 2Factores de riesgo cardiovascular en población universitaria de la Facsal, universidad de TarapacáImplicancias psicosociales en la génesis, evolución y tratamiento de pacientes con hipertensión arterial esencialInfarto agudo al miocardio (IAM): Realidad en el Hospital de Puerto Natales, 2009-2010Introducción de nuevas TIC y mejoría de la asistencia a un programa de saludNiños obesos atendidos en el Cesfam de Puerto Natales y su entorno familiarPerfil de la mortalidad por cáncer de cuello uterino en Río de JaneiroPerfil del paciente primo-consultante del Programa de Salud Cardiovascular, Consultorio Cordillera Andina, Los AndesPrevalencia de automedicación en mujeres beneficiarias del Hospital Comunitario de Til-TiPrevalencia de caries en población preescolar y su relación con malnutrición por excesoPrevalencia de retinopatía diabética en comunas dependientes del Servicio de Salud Metropolitano Occidente (SSMOC)Problemas de adherencia farmacológica antihipertensiva en población mapuche: Un estudio cualitativoRol biológico de los antioxidantes innatos en pacientes portadores de VIH/SidaSobrepeso en empleados de un restaurante de una universidad pública del estado de São Paul

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

Unlocking the Climate Record Stored within Mars’ Polar Layered Deposits

In the icy beds of its polar layered deposits (PLD), Mars likely possesses a record of its recent climate history, analogous to terrestrial ice sheets that contain records of Earth's past climate. Both northern and southern PLDs store information on the climatic and atmospheric state during the deposition of each layer (WPs: Becerra et al.; Smith et al). Reading the climate record stored in these layers requires detailed measurements of layer composition, thickness, isotope variability, and near-surface atmospheric measurements. We identify four fundamental questions that must be answered in order to interpret this climate record and decipher the recent climatic history of Mars: 1. Fluxes: What are the present and past fluxes of volatiles, dust, and other materials into and out of the polar regions? 2. Forcings: How do orbital/axial forcing and exchange with other reservoirs affect those fluxes? 3. Layer Processes: What chemical and physical processes form and modify layers? 4. Record: What is the timespan, completeness, and temporal resolution of the climate history recorded in the PLD? In a peer reviewed report (1), we detailed a sequence of missions, instruments, and architecture needed to answer these questions. Here, we present the science drivers and a mission concept for a polar lander that would enable a future reading of the past few million years of the Martian climate record. The mission addresses as-yet-unachieved science goals of the current Decadal Survey and of MEPAG for obtaining a record of Mars climate and has parallel goals to the NEXSAG and ICE-SAG reports

SISTEMA DE PRODUCCIÓN DE LECHE BASADO EN ALFALFA (Medicago sativa) Y MAÍZ (Zea mays) PARA LA ZONA CENTRO SUR. I PRODUCCIÓN DE LECHE (A milk production system based on lucerne (Medicago sativa) and corn (Zea mays) silage in the central south zone. I Milk production)

For two consecutive years a milk production system was evaluated at Humán Experimental Station, Los Angeles, Chile (37?28`Lat. S and 72?23`Long. W). Four hectares of alfalfa were used alternately for rotational grazing at the prebud stage and for cutting for hay production at the 10% bloom stage. Corn silage (1.8 ha) and alfalfa hay were used during winter. The cows received concentrates throughout the year according to their milk production level. The composition of the concentrate was varied according to season of the year, forage quality and the production level of the cows. Sixteen Holstein cows with calving dates concentrated between May and August were used. Average milk production was 16,889 L ha-1 or 6,300 L cow-1 with a supplementation of 0.256 kg of concentrate per liter of milk produced. The efficiency of alfalfa utilization for grazing varied during the year, with a tendency to be lower in the spring period and higher in summer. A large variation in the efficiency of utilization was observed whose values varied between 26 and 92%. RESUMEN En la Estación Experimental Humán, ubicada cerca de la ciudad de Los Ángeles (37?28`Lat. S y 72?23`Long. O), se evaluó durante dos años consecutivos un sistema de producción de leche, cuya base forrajera fueron 4 hectáreas de alfalfa suministradas como pastoreo rotativo al estado de prebotón y alternativamente como henificación; 1,8 hectáreas de maíz para ensilaje, superficie que se ajustó según consumo real. Las vacas recibieron además concentrados según producción de leche durante todo el año. La composición del concentrado fue variable según la época del año, el nivel productivo de las vacas y la calidad del forraje. Se utilizaron 16 vacas Holstein cuyas pariciones se concentraron entre mayo y agosto. La producción de leche promedio fue de 16889 L ha-1 y 6300 L vaca masa-1 al año, con una suplementación de 0,256 kg de suplemento por litro de leche. La eficiencia de utilización de la alfalfa en pastoreo varió entre las épocas del año, con una tendencia a ser menor en primavera y mayor en el verano. Se observó gran variabilidad en la eficiencia de utilización cuyos valores fluctuaron entre un 26 y 92%

Methyl methacrylate reactivity under electric field in view of an electrically induced polymerization process

We have studied the effect of a static external electric field on electronic properties of methyl methacrylate (MMA) and its consequences in an electro-initiated polymerization by density functional theory (DFT). The Conceptual-DFT scheme is used to obtain hardness (η), electrophilicity (ω) and nucleophilicity (N) for MMA in gas phase and in a dielectric media. These changes on ω and N have been determined as a function of the direction and strength of the external electric field. This study give some insight on the enhancement of reactivity and, therefore, on the polymerization process under the presence of electric fields

INVESTIGACIÓN - MEJORAMIENTO DEL PORCENTAJE DE PROTEÍNA EN MAÍZ PARA ENSILAJE CON EL AUMENTO Y PARCIALIZACIÓN DE LA FERTILIZACIÓN NITROGENADA (Improvement of protein percentage in corn silage with an increase in and partitioning of nitrogen fertilization)

In clay soils with poor drainage two trials were carried out with the objective of determining the effect of nitrogen application on maize (Zea mays L.) for silage on forage yield and protein content. In Trial 1, the treatments were two corn silage hybrids of different growing periods, SX-43 and INIA-150, sown at 90.000 plants ha-1 and four N rates: 0, 100, 200 and 400 kg N ha-1. In Trial 2, the treatments were two N rates: 200 and 400 kg of N ha-1, and three forms of N application: a) 1/2 at sowing + 1/2 at 30 cm plant height; b) 1/3 at sowing + 1/3 at 30 cm plant height + 1/3 at 60 cm plant height; and c) 1/4 at sowing + 1/4 at 30 cm plant height + 1/4 at 60 cm plant height +1/4 at flowering. One treatment was without N. In Trial 1 N application increased DM yield (P < 0.05), but no significant response was observed with N rates between 100 and 400 kg N ha-1, due to soil limitations. Forage production and protein percentage increased significantly with N application. In Trial 2, DM production in corn silage increased with higher N rates (P < 0.05). Forage protein percentage was increased by higher N rates and partitioning of the application. On increasing the partitioning of N from two to four applications, protein percentage of forage was increased by 23 and 37% for 200 and 400 kg of N ha-1, respectively