Absorption, distribution and accumulation of nitrogen applied at different phenological stages in southern highbush blueberry (Vaccinium corymbosum interspecific hybrid)

Southern highbush blueberry has an early harvesting and then a long period of vegetative growth until dormancy, compared to highbush and rabbiteye blueberries. Nitrogen requirements could be different because of this specific early harvesting. Absorption of 15N enriched ammonium sulfate was compared at five phenological stages from bud swell to pre-dormancy in two years old plants of the cultivars Star and ÓNeal. Plants grown in pots were irrigated with ammonium sulfate solution (15N). Five plants for each application date were excavated and separated in parts (roots, canes, leaves, flowers, fruits or floral buds). Samples were taken three weeks after application from bud swell to pre-harvest treatment, and three month after for post-harvest and pre-dormancy treatment. Each tissue were dried and weighed before and after, and analyzed for 15N content, N content and N %….N%, and in leaves were also determined macro and micro nutrients. Nitrogen fertilization at bud swell is effective, even for the ÓNeal cultivarthat present floral bud break in absence of leaves. Post-harvest fertilization contribute N for summer vegetativegrowth which would influence the floral buds development next year, Nitrogenstorage at this time would led to the improved floral behavior next year. Nitrogen losses risk is lower at post-harvestfertilization.Fil: Pescie, María A.. Universidad Nacional de Lomas de Zamora. Facultad de Ciencias Agrarias; ArgentinaFil: Borda, Marcela P.. Universidad Nacional de Lomas de Zamora. Facultad de Ciencias Agrarias; ArgentinaFil: Ortiz, Daniela P.. Universidad Nacional de Lomas de Zamora. Facultad de Ciencias Agrarias; ArgentinaFil: Landriscini, María Rosa. Universidad Nacional del Sur. Departamento de Agronomía. Área Suelos y Aguas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; ArgentinaFil: Lavado, Raul Silvio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales; Argentin

Efecto del momento y tipo de poda sobre el rendimiento y calidad del fruto en arándano altos del sur (Vaccinium corymbosum) var. O´Neal en la provincia de Buenos Aires

La poda es una práctica que beneficia no sólo la calidad y cantidad de los frutos, sino también favorece la preservación de la planta como unidad productiva. Tiene distintos objetivos dependiendo de su intensidad y del momento de realización. En la Argentina, no se conoce cuál es el tipo de poda más beneficiosa para el arándano (Vaccinium corymbosum) en las diferentes zonas de producción y variedades utilizadas. Para estudiar su efecto, durante dos años consecutivos (2007 y 2008), se implementaron cuatro tratamientos de poda en plantas adultas de arándano de la var. O´Neal en el norte de la Provincia de Buenos Aires: 1) en invierno (PI), 2) en invierno y despunte de verano (PIDV), 3) intensa en verano (PIV) y 4) testigo sin podar (testigo). Como resultado, se observó que las plantas testigo y PIDV no mostraron diferencia significativa entre sí en cuanto a rendimiento (5,58 y 4,94 kg/planta, respectivamente), pero las PIDV mostraron un tamaño promedio de fruto significativamente mayor (>0.21 g/fruto) y precocidad en la cosecha. Se requirieron 64 minutos menos por año para cosechar las plantas PIDV, comparadas con las plantas testigo. El tamaño de fruto mejoró significativamente con la poda, independientemente del momento o de la intensidad. Sin embargo, las plantas PIV mostraron una reducción significativa del rendimiento de 3,6 kg/planta con respecto al control en el promedio de los 2 años, con una caída del 23% en el rendimiento de 2008 comparado con 2007.Pruning is a beneficial practice to improve yield and fruit quality, used in most of fruit trees. It has different goals depending on intensity and whether it takes place in winter or summer. Which type of pruning is better for blueberry production in local climatic conditions, management and cultivars has not been investigated. Hence, four pruning treatments were studied in mature O’Neal plants during two consecutive years, 2007 and 2008, in Buenos Aires northeast region: 1) conventional winter pruning (PI), 2) conventional winter pruning and summer tip pruning after fruit harvest (PIDV), 3) removal of older canes in summer, after fruit harvest (PIV) and 4) control (no pruning). Control and PIDV plants had no significant differences in yield (5.6 and 4.9 kg/plant, respectively), but average fruit weight in PIDV plants was significantly greater than in unpruned plants (1.38 and 1.17 g, respectively) and plants produced earlier. In addition, 64 min less where needed to harvest PIDV plants, compared to unpruned plants. Fruit size was significantly increased with prune treatments, regardless of pruning moment and intensity, but PIV plants showed a significant yield reduction of 3.6 kg/plant, compared to PVDV and unpruned plants, and a 23% yield reduction from 2007 to 2008.Gerencia de Comunicación e Imagen Institucional, DNA SICC, INTAFil: Pescie, María Angeles. Universidad Nacional de Lomas de Zamora. Facultad de Ciencias Agrarias; ArgentinaFil: Borda, Marcela P. Universidad Nacional de Lomas de Zamora. Facultad de Ciencias Agrarias; ArgentinaFil: Fedyszak, P. Universidad Nacional de Lomas de Zamora. Facultad de Ciencias Agrarias; ArgentinaFil: López, César. Universidad Nacional de Lomas de Zamora. Facultad de Ciencias Agrarias; Argentin

Seroprevalence of anti-SARS-CoV-2 antibodies in Colombia, 2020: A population-based study

BackgroundSevere acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to cause very high morbidity and mortality throughout Latin American countries. However, few population-based seroprevalence surveys have been conducted to quantify attack rates and characterize drivers of transmission.MethodsWe conducted a population-based cross-sectional study to assess the seroprevalence of antibodies against SARS-CoV-2 in ten cities in Colombia between September and December 2020. The study involved multi-stage cluster sampling at each city. Participants provided a serum sample and answered a demographic and risk factor questionnaire. Prior infection by SARS-CoV-2 was ascertained using the "SARS-CoV-2 Total (COV2T) Advia Centaur - Siemens" chemiluminescence assay.FindingsA total of 17863 participants from 7320 households participated in the study. Seroprevalence varied substantially between cities, ranging from 26% (95%CI 23-29 %) in Medellín to 68% (95%CI 62-74 %) in Guapi. There were no differences in seroprevalence by sex, but seropositivity was higher in certain ethnic groups. There was substantial heterogeneity in seroprevalence within cities, driven to a large extent by a strong association between socioeconomic stratum and seropositivity.InterpretationColombia has been one of the Latin American countries most affected by the COVID-19 pandemic. This study documented very high attack rates in several Colombian cities by the end of 2020 and identified key drivers of heterogeneities including ethnicity and socioeconomic stratum. Few studies of seroprevalence of SARS-CoV-2 have been conducted in Latin America, and therefore this study contributes to the fundamental understanding of the pandemic in the region.FundingThe study was sponsored by, Ministerio de Ciencia y Tecnología e Innovación -CT361/2020, Ministerio de Salud y Protección Social, Fundación Universitaria del Norte, Imperial College of London, Universidad Nacional de Colombia (Sede Medellín), Universidad de Córdoba, California University, Unidad Nacional de Gestión del Riesgo, Centro de Atención y Diagnóstico de Enfermedades Infecciosas -CDI-, Centro Internacional de Entrenamiento e Investigaciones Médicas -CIDEIM-, Departamento Administrativo Nacional de Estadística - DANE, Fondo Nacional de Turismo -FONTUR-, Secretarías de Salud Departamentales, Distritales y Municipales and Instituto Nacional de Salud

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