Impact of tillage and N fertilization rate on soil N2O emissions in irrigated maize in a Mediterranean agroecosystem

In irrigated Mediterranean conditions there is a lack of knowledge about the best combination of tillage and N fertilization practices to reduce soil nitrous oxide (N2O) emissions while maintaining maize productivity. The aim of this work was to investigate the effects of different soil management practices and synthetic N fertilization rates on soil N2O emissions and their relationship with maize grain yield to determine the best management system to reduce yield-scaled N2O emissions (YSNE) in a semiarid area recently converted to irrigation under Mediterranean conditions. A long-term tillage and N rate field experiment established in 1996 under barley (Hordeum vulgare L.) rainfed conditions, was converted to irrigated maize (Zea mays L.) in 2015. After the transformation to irrigation, the field experiment maintained the same tillage treatments and N fertilization rates. Three types of tillage (conventional tillage, CT; reduced tillage, RT; no-tillage, NT) and three mineral N fertilization rates (0, 200, 400 kg N ha−1) were compared during three years (2015-2017) in a randomized block design with three replications. Soil N2O emissions, water-filled pore space, soil temperature, mineral N content (as NH4+ and NO3−), denitrification potential and maize grain yield and above-ground N uptake were quantified. Moreover, the emission factor (EF) and YSNE were calculated. The results showed that the combination of NT and the highest rate of N fertilization led to greater N2O emissions. Furthermore, the lowest N2O fluxes were observed in CT when WFPS was below 40% and the highest N2O fluxes were seen in NT when WFPS was above 60% coinciding with the greatest denitrification potential. Cumulative N2O emissions in 2017 and 2015 followed the order 400 > 200 > 0 kg N ha−1, while in 2016, rate of 400 and 200 kg N ha−1 showed greater cumulative N2O emission compared to the control. Only RT showed differences between growing seasons on cumulative N2O emissions, with greater values in 2017 compared to 2015, and intermediate values in 2016. In all treatments, the N2O EF was much lower than the default IPCC emission factor (1%). NT and RT increased the grain production compared to CT which was affected by severe soil crusting causing water deficit. Likewise, N fertilizer treatments significantly affected the YSNE, increasing with increasing fertilizer N application rate in the first year of study. Our data show that the use of NT or RT does not lead to more yield-scaled N2O emissions than CT in Mediterranean agroecosystems recently converted to irrigation.This research work was financially supported by the Ministerio de Economía y Competitividad of Spain (project AGL2013-49062-C4-1-R; PhD fellowship BES‐2014‐070039). DPB received a Juan de la Cierva postdoctoral grant from the Ministerio de Economía y Competitividad of Spain (IJCI-2016-27784)

Is it feasible to reduce tillage and N use while improving maize yield in irrigated Mediterranean agroecosystems?

Mediterranean rainfed areas are transformed into irrigation to stabilize or increase crop yields. The gradual occupation of irrigation leads to an increase in nitrogen use and intensity of tillage. The aim of this work was to evaluate the combined impact of tillage systems and mineral N fertilization rates on maize grain yield, water and nitrogen use efficiencies (WUE and NUE) under Mediterranean irrigated conditions. The study was carried out in NE Spain during three maize growing seasons (i.e. years 2015, 2016 and 2017). A long-term (LTE) tillage and N rate field experiment established in 1996 under rainfed conditions was transformed into irrigation with maize (Zea mays L.) monoculture as cropping system in 2015. Three types of tillage (conventional tillage, CT; reduced tillage, RT; no-tillage, NT) and three mineral N fertilization rates (0, 200, 400 kg N ha-1) were compared in a randomized block design with three replications. In 2015, an adjacent experiment (short-term experiment, STE) with the same layout was set up in an area previously managed under long-term rainfed NT for the last 21 years. Soil water (SWC) and nitrate (SNC) content were quantified. Maize above ground biomass and N uptake, grain yield and yield components, grain N were measured at harvest. The WUE for above ground biomass and yield (WUEB and WUEY, respectively) and NUE, as well as other N-related indexes (nitrogen harvest index, NHI; apparent nitrogen recovery efficiency, NAR) were calculated. In the long-term tillage and N fertilization combination (LTE), the reduction of tillage (NT and RT) led to greater grain yield when applying 200 and 400 kg N ha-1 compared to the use of the same rates under CT. Differently, in the sort-term experiment with preceding NT (STE), tillage systems did not influence grain yields, while N application led to greater yields than the control (0 kg N ha-1). In both situations (LTE and STE), NT and RT enhanced SWC before planting leading to greater crop growth compared to CT. The lack of available water under CT caused lower maize above-ground biomass, yield, and yield components in LTE and, therefore, lower WUEB and WUEY. In LTE, the use of long-term CT led to a significant accumulation of nitrate compared to NT. Differently, in the STE, SNC did not show differences between tillage systems. In the LTE, water and N were used more efficiently to produce above-ground biomass and grain yield in RT and NT. Our study shows that in Mediterranean agroecosystems transformed into irrigation the use of NT and RT with medium rates of N leads to greater maize yield, WUE and NUE than the traditional management based on CT with high rates of mineral N. In rainfed areas with long-term history of no-till, this soil management system can be successfully maintained if transformed into irrigation.We would like to thank the field and laboratory technicians Javier Bareche, Carlos Cortés, Barbara Jelcic and Silvia Martí. This research work was financially supported by the Ministerio de Economía y Competitividad of Spain (project AGL2013-49062-C4-1-R; PhD fellowship BES‐2014‐070039). DPB received a Juan de la Cierva postdoctoral grant from the Ministerio de Economía y Competitividad of Spain (IJCI-2016-27784)

Tillage and nitrogen fertilization in irrigated maize: key practices to reduce soil CO2 and CH4 emissions

In newly irrigated Mediterranean agroecosystems, the combined effect of tillage and N fertilization on soilcarbon dioxide (CO2) and methane (CH4)fluxes is at present poorly understood. The goal of this study was toquantify both soil CO2and CH4emissions as well as crop performance under different tillage systems and Nfertilization rates during three maize (Zea maysL.) growing seasons (2015-2017) in a semiarid area converted toirrigated. Three types of tillage (conventional tillage, CT, reduced tillage, RT, and no-tillage, NT) and threemineral N fertilization rates (0, 200, and 400 kg N ha−1) were compared in a randomized block design withthree replications. Weekly soil CO2and CH4emissions, soil temperature and gravimetric moisture were mea-sured. Moreover, maize above-ground biomass, grain yield, and above-ground C-inputs were quantified. Carbondioxide emissions ranged from 173 to 4378 mg CO2-C m-2d-1. No-tillage showed a greater mean soil CO2fluxthan CT when applying the highest rate of N (400 kg N ha-1). Although some emissions of CH4were observed, alltreatments acted as net CH4sinks during most of the experimental period. A linear multiple relationship betweensoil CO2fluxes and soil gravimetric moisture (0-5 cm depth) and temperature (10 cm depth) were found. In the2015 growing season, greater cumulative CO2emissions were found under NT and RT compared with CT, whilein 2016 N T showed the highest values compared to CT with intermediate values in RT. Differently, in 2017 nodifferences between tillage systems were found. When applying N fertilizer, NT and RT increased maize grainproduction and above-ground C-inputs compared to CT, since a severe soil crusting occurred in this last, whichcaused crop water deficit. The results suggest that tillage intensity and N fertilization rate reduction can increasemaize biomass production and yield which leads to greater C-input that returns to the soil.We would like to thank the field and laboratory technicians Carlos Cortés, Barbara Jelcic, Javier Bareche and Silvia Martí. This research work was financially supported by the Ministerio de Economía y Competitividad of Spain (project AGL2013-49062-C4-1-R; PhD fellowship BES‐2014‐070039). DPB received a Juan de la Cierva postdoctoral grant from the Ministerio de Economía y Competitividad of Spain (IJCI-2016-27784)

The impact of surgical delay on resectability of colorectal cancer: An international prospective cohort study

AIM: The SARS-CoV-2 pandemic has provided a unique opportunity to explore the impact of surgical delays on cancer resectability. This study aimed to compare resectability for colorectal cancer patients undergoing delayed versus non-delayed surgery. METHODS: This was an international prospective cohort study of consecutive colorectal cancer patients with a decision for curative surgery (January-April 2020). Surgical delay was defined as an operation taking place more than 4 weeks after treatment decision, in a patient who did not receive neoadjuvant therapy. A subgroup analysis explored the effects of delay in elective patients only. The impact of longer delays was explored in a sensitivity analysis. The primary outcome was complete resection, defined as curative resection with an R0 margin. RESULTS: Overall, 5453 patients from 304 hospitals in 47 countries were included, of whom 6.6% (358/5453) did not receive their planned operation. Of the 4304 operated patients without neoadjuvant therapy, 40.5% (1744/4304) were delayed beyond 4 weeks. Delayed patients were more likely to be older, men, more comorbid, have higher body mass index and have rectal cancer and early stage disease. Delayed patients had higher unadjusted rates of complete resection (93.7% vs. 91.9%, P = 0.032) and lower rates of emergency surgery (4.5% vs. 22.5%, P < 0.001). After adjustment, delay was not associated with a lower rate of complete resection (OR 1.18, 95% CI 0.90-1.55, P = 0.224), which was consistent in elective patients only (OR 0.94, 95% CI 0.69-1.27, P = 0.672). Longer delays were not associated with poorer outcomes. CONCLUSION: One in 15 colorectal cancer patients did not receive their planned operation during the first wave of COVID-19. Surgical delay did not appear to compromise resectability, raising the hypothesis that any reduction in long-term survival attributable to delays is likely to be due to micro-metastatic disease

Base de datos de abejas ibéricas

Las abejas son un grupo extremadamente diverso con más de 1000 especies descritas en la península ibérica. Además, son excelentes polinizadores y aportan numerosos servicios ecosistémicos fundamentales para la mayoría de ecosistemas terrestres. Debido a los diversos cambios ambientales inducidos por el ser humano, existen evidencias del declive de algunas de sus poblaciones para ciertas especies. Sin embargo, conocemos muy poco del estado de conservación de la mayoría de especies y de muchas de ellas ignoramos cuál es su distribución en la península ibérica. En este trabajo presentamos un esfuerzo colaborativo para crear una base de datos de ocurrencias de abejas que abarca la península ibérica e islas Baleares que permitirá resolver cuestiones como la distribución de las diferentes especies, preferencia de hábitat, fenología o tendencias históricas. En su versión actual, esta base de datos contiene un total de 87 684 registros de 923 especies recolectados entre 1830 y 2022, de los cuales un 87% presentan información georreferenciada. Para cada registro se incluye información relativa a la localidad de muestreo (89%), identificador y colector de la especie (64%), fecha de captura (54%) y planta donde se recolectó (20%). Creemos que esta base de datos es el punto de partida para conocer y conservar mejor la biodiversidad de abejas en la península ibérica e Islas Baleares. Se puede acceder a estos datos a través del siguiente enlace permanente: https://doi.org/10.5281/zenodo.6354502ABSTRACT: Bees are a diverse group with more than 1000 species known from the Iberian Peninsula. They have increasingly received special attention due to their important role as pollinators and providers of ecosystem services. In addition, various rapid human-induced environmental changes are leading to the decline of some of its populations. However, we know very little about the conservation status of most species and for many species, we hardly know their true distributions across the Iberian Peninsula. Here, we present a collaborative effort to collate and curate a database of Iberian bee occurrences to answer questions about their distribution, habitat preference, phenology, or historical trends. In total we have accumulated 87 684 records from the Iberian Peninsula and the Balearic Islands of 923 different species with 87% of georeferenced records collected between 1830 and 2022. In addition, each record has associated information such as the sampling location (89%), collector and person who identified the species (64%), date of the capture (54%) and plant species where the bees were captured (20%). We believe that this database is the starting point to better understand and conserve bee biodiversity in the Iberian Peninsula. It can be accessed at: https://doi.org/10.5281/zenodo.6354502Esta base de datos se ha realizado con la ayuda de los proyectos EUCLIPO (Fundação para a Ciência e a Tecnologia, LISBOA-01-0145-FEDER-028360/EUCLIPO) y SAFEGUARD (ref. 101003476 H2020 -SFS-2019-2).info:eu-repo/semantics/publishedVersio

4to. Congreso Internacional de Ciencia, Tecnología e Innovación para la Sociedad. Memoria académica

Este volumen acoge la memoria académica de la Cuarta edición del Congreso Internacional de Ciencia, Tecnología e Innovación para la Sociedad, CITIS 2017, desarrollado entre el 29 de noviembre y el 1 de diciembre de 2017 y organizado por la Universidad Politécnica Salesiana (UPS) en su sede de Guayaquil. El Congreso ofreció un espacio para la presentación, difusión e intercambio de importantes investigaciones nacionales e internacionales ante la comunidad universitaria que se dio cita en el encuentro. El uso de herramientas tecnológicas para la gestión de los trabajos de investigación como la plataforma Open Conference Systems y la web de presentación del Congreso http://citis.blog.ups.edu.ec/, hicieron de CITIS 2017 un verdadero referente entre los congresos que se desarrollaron en el país. La preocupación de nuestra Universidad, de presentar espacios que ayuden a generar nuevos y mejores cambios en la dimensión humana y social de nuestro entorno, hace que se persiga en cada edición del evento la presentación de trabajos con calidad creciente en cuanto a su producción científica. Quienes estuvimos al frente de la organización, dejamos plasmado en estas memorias académicas el intenso y prolífico trabajo de los días de realización del Congreso Internacional de Ciencia, Tecnología e Innovación para la Sociedad al alcance de todos y todas

Omecamtiv mecarbil in chronic heart failure with reduced ejection fraction, GALACTIC‐HF: baseline characteristics and comparison with contemporary clinical trials

Aims: The safety and efficacy of the novel selective cardiac myosin activator, omecamtiv mecarbil, in patients with heart failure with reduced ejection fraction (HFrEF) is tested in the Global Approach to Lowering Adverse Cardiac outcomes Through Improving Contractility in Heart Failure (GALACTIC‐HF) trial. Here we describe the baseline characteristics of participants in GALACTIC‐HF and how these compare with other contemporary trials. Methods and Results: Adults with established HFrEF, New York Heart Association functional class (NYHA) ≥ II, EF ≤35%, elevated natriuretic peptides and either current hospitalization for HF or history of hospitalization/ emergency department visit for HF within a year were randomized to either placebo or omecamtiv mecarbil (pharmacokinetic‐guided dosing: 25, 37.5 or 50 mg bid). 8256 patients [male (79%), non‐white (22%), mean age 65 years] were enrolled with a mean EF 27%, ischemic etiology in 54%, NYHA II 53% and III/IV 47%, and median NT‐proBNP 1971 pg/mL. HF therapies at baseline were among the most effectively employed in contemporary HF trials. GALACTIC‐HF randomized patients representative of recent HF registries and trials with substantial numbers of patients also having characteristics understudied in previous trials including more from North America (n = 1386), enrolled as inpatients (n = 2084), systolic blood pressure &lt; 100 mmHg (n = 1127), estimated glomerular filtration rate &lt; 30 mL/min/1.73 m2 (n = 528), and treated with sacubitril‐valsartan at baseline (n = 1594). Conclusions: GALACTIC‐HF enrolled a well‐treated, high‐risk population from both inpatient and outpatient settings, which will provide a definitive evaluation of the efficacy and safety of this novel therapy, as well as informing its potential future implementation

Caracterización físico–química del agregado pétreo del rio negro en la ciudad de Villavicencio (Meta)

Debido al crecimiento poblacional de la ciudad de Villavicencio y al incremento en la industria de la construcción en el departamento del Meta, ha sido de gran importancia evaluar los materiales pétreos extraídos del Rio Negro para la realización de ensayos y la confirmación de la calidad de dicho material en la fabricación de concretos y en la utilización como material para bases y sub bases en vías, para ello se tiene en cuenta la Norma NTC 174 e I.N.V E-200-2013, en las cuales se describen los ensayos de laboratorio tales como el análisis granulométrico de agregados gruesos y finos, densidad bulk y porcentaje de vacíos de los agregados compactados o sueltos, sanidad de los agregados frente a la acción de las soluciones de sulfato de sodio o de magnesio, cantidad de partículas livianas en los agregados pétreos, gravedad específica y absorción de agregados gruesos y finos, porcentaje de caras fracturadas en los agregados, índice de aplanamiento y de alargamiento de los agregados, determinación de terrones de arcilla y partículas deleznables en los agregados, contenido aproximado de materia orgánica en arenas usadas en la preparación de morteros o concretos, equivalente de arena de suelos y agregados finos, determinación del material que pasa por el tamiz de 75 μm (Nº 200) en los agregados pétreos mediante lavado, análisis granulométrico del llenante mineral utilizado en la elaboración de mezclas asfálticas, determinación del valor de 10% de finos, determinación de la resistencia del agregado grueso a la degradación por abrasión utilizando el aparato micro-Deval, para determinar tanto su limpieza como el contenido de sustancias perjudiciales, su durabilidad, absorción, granulometría y geometría de las partículas, lo que facilita el alcance y la caracterización de este estudio. Luego de tomada el material que fue extraída en el Rio negro del municipio de Villavicencio (META) fue dirigida en su totalidad a el laboratorio de la empresa INGECIV C&C LTDA y posterior mente una verificación con el acompañamiento del ingeniero mateo Agudelo Varela; donde se realiza la respectiva caracterización físico – química del material seleccionado, seguido a esto, se recogen los diferentes resultados dados por las formulas y las especificaciones técnicas de la norma I.N.V 200-2013 para agregados pétreos, seguido a ello se comparan los datos tomando los más factibles para el proceso y los cuales se encuentren cerca o entre el rango que establece la calidad del material, para ser implementados en las diferentes actividades de obras civiles