Nitrogen use efficiency and residual effect of fertilizers withnitrification inhibitors

Blending fertilizers with nitrification inhibitors (NI) is a technology to reduce nitrogen (N) losses. The application of NI could increase the soil N supply capacity over time and contribute to an enhancement of N-fertilizer recovery in some cropping systems. During two seasons, a field experiment with maize (Zea mays L.) was fertilized with ammonium sulfate nitrate (ASN) and DMPP (3,4 dimethylpyrazole phosphate) blended ASN (ENTEC) at two levels (130 and 170 kg N ha-1) under Mediterranean conditions. A control treatment with no added N fertilizer was also included. Maize yield, grain quality, nutritional state and fertilizer use efficiency were evaluated. Due to the observation of a soil residual effect, a non-fertilized sunflower (Helianthus annuus L.) was planted in the same plots to study the cumulative effect during a third experimental season. Laboratory determinations were performed in order to elucidate the possible sources of residual N. The second year, DMPP application allowed a 23% reduction of the fertilizer rate without decreasing crop yield or grain quality. In addition, the non-fertilized sunflower planted after the maize scavenge more N in treatments previously treated with ENTEC than with traditional fertilizers, increasing N use efficiency in the cropping systems. After DMPP application, N was conserved in non-ready soil available forms during at least one year and subsequently released to meet the sunflower crop demand. The potential N mineralization obtained from aerobic incubation under controlled conditions of soil samples collected before sunflower sowing was higher for ENTEC than ASN or control treatments. A higher δ15N in the soil indicated larger non-exchangeable NH4+ fixation in soils from the plots treated with ENTEC or ASN-170 than from the ASN-130 or the control. These results open the opportunity to increase N efficiency by designing crop rotations able to profit from the effect of NI on the soil residual N

A computational comparison of several formulations for the multi-period incremental service facility location problem

The Multi-period Incremental Service Facility Location Problem, which was recently introduced, is a strategic problem for timing the location of facilities and the assignment of customers to facilities in a multi-period environment. Aiming at finding the strongest formulation for this problem, in this work we study three alternative formulations based on the so-called impulse variables and step variables. To this end, an extensive computational comparison is performed. As a conclusion, the hybrid impulse–step formulation provides better computational results than any of the other two formulations

Arsenic distribution in a pasture area impacted by past mining activities

[EN]Former mine exploitations entail a serious threat to surrounding ecosystems as after closure of mining activities their unmanaged wastes can be a continuous source of toxic trace elements. Quite often these mine sites are found within agricultural farming areas, involving serious hazards as regards product (feed/food) quality. In this work a grazing land impacted by the abandoned mine exploitation of an arsenical deposit was studied so as to evaluate the fate of arsenic (As) and other trace elements and the potential risks involved. With this aim, profile soil samples (0–50 cm) and pasture plant species (Agrostis truncatula, Holcus annus and Leontodon longirostris) were collected at different distances (0–100 m) from the mine waste dump and analyzed for their trace element content and distribution. Likewise, plant trace element accumulation from impacted grazing soils and plant trace element translocation were assessed. The exposure of livestock grazing animals to As was also evaluated, establishing its acceptability regarding food safety and animal health. International soil guideline values for As in grazing land soils (50 mg kg−1) resulted greatly exceeded (up to about 20-fold) in the studied mining-affected soils. Moreover, As showed a high mobilization potential under circumstances such as phosphate application or establishment of reducing conditions. Arsenic exhibited relatively high translocation factor (TF) values (up to 0.32–0.89) in pasture plant species, reaching unsafe concentrations in their above-ground tissues (up to 32.9, 16.9 and 9.0 mg kg−1 in Agrostis truncatula, Leontodon longirostris and Holcus annus, respectively). Such concentrations represent an elevated risk of As transfer to the high trophic-chain levels as established by international legislation. The limited fraction of arsenite found in plant roots should play an important role in the relatively high As root-to-shoot translocation shown by these plant species. Both soil ingestion and pasture intake resulted important entrance pathways of As into livestock animals, showing quite close contribution levels. The cow acceptable daily intake (ADI) of As regarding food safety was surpassed in some locations of the study area when the species Agrostis truncatula was considered as the only pasture feed. Restrictions in the grazing use of lands with considerable As contents where this plant was the predominant pasture species should be established in order to preserve food quality. Therefore, the exposure of livestock animals to As via both soil ingestion and pasture consumption should be taken into account to establish the suitability of mining-impacted areas for gazing

Quantitative characterization of five cover crop species

The introduction of cover crops in the intercrop period may provide a broad range of ecosystem services derived from the multiple functions they can perform, such as erosion control, recycling of nutrients or forage source. However, the achievement of these services in a particular agrosystem is not always required at the same time or to the same degree. Thus, species selection and definition of targeted objectives is critical when growing cover crops. The goal of the current work was to describe the traits that determine the suitability of five species (barley, rye, triticale, mustard and vetch) for cover cropping. A field trial was established during two seasons (October to April) in Madrid (central Spain). Ground cover and biomass were monitored at regular intervals during each growing season. A Gompertz model characterized ground cover until the decay observed after frosts, while biomass was fitted to Gompertz, logistic and linear-exponential equations. At the end of the experiment, carbon (C), nitrogen (N), and fibre (neutral detergent, acid and lignin) contents, and the N fixed by the legume were determined. The grasses reached the highest ground cover (83–99%) and biomass (1226–1928 g/m2) at the end of the experiment. With the highest C:N ratio (27–39) and dietary fibre (527–600 mg/g) and the lowest residue quality (~680 mg/g), grasses were suitable for erosion control, catch crop and fodder. The vetch presented the lowest N uptake (2·4 and 0·7 g N/m2) due to N fixation (9·8 and 1·6 g N/m2) and low biomass accumulation. The mustard presented high N uptake in the warm year and could act as a catch crop, but low fodder capability in both years. The thermal time before reaching 30% ground cover was a good indicator of early coverage species. Variable quantification allowed finding variability among the species and provided information for further decisions involving cover crop selection and management

Infancia, juventud y migraciones. Una mirada para la cooperación internacional

Depto. de Sociología AplicadaFac. de Ciencias Políticas y SociologíaTRUEpu

Modelos para el cálculo de consumo y emisiones gaseosas de la flota de autobuses de Madrid

En este trabajo se presentan algunos resultados del estudio experimental de cálculo de emisiones emanadas en condiciones concretas de la explotación del servicio de la flota de vehículos del transporte público de pasajeros de la ciudad de Madrid, realizado en el marco de cooperación entre grupos de investigación del Instituto Universitario de Investigación del Automóvil (INSIA) de la Universidad Politécnica de Madrid y del Instituto de Desarrollo Industrial (IIDISA) de la Universidad Nacional de Salta. La experiencia consistió en la adquisición de datos de emisiones de contaminantes y consumo de combustible mediante un equipo de medida de emisiones a bordo en un vehículo de prueba en condiciones reales de explotación, en los que se tomaron además, datos de variables cinemáticas en distintas líneas y recorridos representativos de las que conforman el servicio de la Empresa Municipal de Transportes de Madrid. Con los datos adquiridos se han ajustado modelos para la estimación de emisiones contaminantes y consumo en un escenario de 30 ciclos, con el objetivo de obtener valores por unidad (30 ciclos) que pueden ser utilizados como valores de referencia. Por razones de extensión, en este estudio se presentan los resultados del modelo estadístico para el cálculo del consumo y las emisiones totales de CO2 ajustado en función de variables cinemáticas como la velocidad media del autobús y el tiempo, en una de las líneas de servicio más largas de la ciudad: la línea Circular Uno (C1). Las expresiones obtenidas permiten estimar el consumo de combustibles y emisiones de CO2 con valores del coeficiente de correlación superior al 70%. A su vez, es posible realizar un análisis de la gestión de la flota de transporte inspirada en la comparación de los ciclos de operación de las líneas y la evaluación de los impactos producidos por la sustitución de vehículos y combustible

Maize diversification and nitrogen fertilization effects on soil nitrous oxide emissions in irrigated mediterranean conditions

Maize is a major irrigated crop in Mediterranean areas and its typical intensive management may impact soil nitrous oxide (N$_{2}$O) emissions. In these irrigated continuous maize systems, the legumes incorporation as well as adjusted nitrogen (N) fertilization might be interesting strategies to reduce soil N$_{2}$O emissions. The objective of this study was to assess the impact of cropping diversification and different N rates on soil N$_{2}$O emissions in flooded irrigated maize under Mediterranean conditions. To achieve this, two cropping systems (maize monoculture system, MC; and pea -maize rotation, MP) and 3N rates (unfertilized, 0N; medium rate, MN; and high rate, HN) were evaluated in a field experiment established in NE Spain during 2 years (2019; 2020). During the studied period, the N rate had a significant effect on soil N$_{2}$O emissions, with a non-linear positive response of cumulative soil N$_{2}$O emissions to N rates. In both systems, quick and high increases of soil N$_{2}$O fluxes were observed immediately after the N application reaching 55 and 100 mg N$_{2}$O-N m$^{−2}$ day$^{−1}$ in MC and MP, respectively. Both years, the pea phase of the MP rotation showed greater cumulative N2O emissions than the fallow of MC. However, N$_{2}$O losses in the maize phase were similar (2019) or even higher (2020) in MC than in MP. Moreover, in both seasons, the MN treatments showed lower yield-scaled N$_{2}$O emissions and N emission factor than the HN treatments, being this last lower than 1% in all cases. The results obtained showed that in irrigated Mediterranean conditions the replacement of a fallow by a legume, together with an adjusted N fertilization are favourable strategies to mitigate soil N$_{2}$O emissions in high-yielding maize systems

Sobre las colecciones burgalesas y otras europeas de Enrique Pérez Arbeláez (1896-1972), depositadas en el Herbario Nacional Colombiano, 3

About Spanish and other European plant collections of Enrique Pérez Arbeláez deposited in the Colombian National Herbarium. After a introduction dedicated to gloss the personality of the Colombian botanist, stopping in some biographical notes, a critical relationship is made on the 214 sheets of the Herbarium of Enrique Pérez Arbeláez. Collections in Europe, collected in Spain between 1922 and 1925, deposited in the Colombian National Herbarium (COL)

Effects of the intake of dairy products naturally enriched with selenium and omega-3 polyunsaturated fatty acids in a sample of postmenopausal women with metabolic syndrome: a randomized, triple-blind, placebo-controlled clinical trial

[ES] Introducción: el síndrome metabólico de las mujeres posmenopáusicas puede mejorar con una alimentación saludable. Objetivos: evaluar si una intervención alimentaria con productos lácteos enriquecidos en selenio y ácidos grasos poliinsaturados omega-3 aumenta los niveles de selenio y mejora los factores de riesgo cardiovascular en las mujeres posmenopáusicas con síndrome metabólico. Material y métodos: ensayo clínico aleatorizado, triple ciego y controlado, realizado en atención primaria. Captación: abril 2018, 46 mujeres posmenopáusicas con síndrome metabólico consumidoras habituales de lácteos. Aleatorización: 23 en el grupo de control y 23 en el grupo experimental. Intervención: consumo durante 3 meses de lácteos enriquecidos naturalmente con selenio y ácidos grasos poliinsaturados omega-3 (leche, yogur y queso fresco). Controles: consumo de lácteos convencionales. Variable principal: selenio en plasma; secundarias: criterios del síndrome metabólico. Número de registro 2018/256, Comité de Ética Galicia. Resultados: finalizaron 23 mujeres en el grupo de control y 21 en el grupo de intervención. Aumentó el selenio en el grupo de intervención (7,2 µg/L, IC del 95 %: 3,7/10,8) frente al grupo de control (-4,5 µg/L, IC del 95 %: -8/-1) (p < 0,001) y disminuyó el colesterol unido a lipoproteínas de muy baja densidad (-2,3 mg/dl, IC del 95 %: -5,6/1) respecto al grupo de control (1,9 mg/dl, IC del 95 %: -0,7/4,5) (p = 0,043). Las mujeres del grupo experimental mejoraron respecto a su medición basal en perímetro de cintura (p = 0,010), índice de masa corporal (p = 0,047) y colesterol unido a lipoproteínas de alta densidad (p < 0,001). Conclusiones: una intervención con lácteos enriquecidos naturalmente con selenio y omega-3 en mujeres posmenopáusicas con síndrome metabólico puede mejorar los niveles de selenio en plasma y de colesterol unido a lipoproteínas de muy baja densidad.S

p73 deficiency results in impaired self renewal and premature neuronal differentiation of mouse neural progenitors independently of p53

[EN] The question of how neural progenitor cells maintain its self-renewal throughout life is a fundamental problem in cell biology with implications in cancer, aging and neurodegenerative diseases. In this work, we have analyzed the p73 function in embryonic neural progenitor cell biology using the neurosphere (NS)-assay and showed that p73-loss has a significant role in the maintenance of neurosphere-forming cells in the embryonic brain. A comparative study of NS from Trp73-/-, p53KO, p53KO;Trp73-/- and their wild-type counterparts demonstrated that p73 deficiency results in two independent, but related, phenotypes: a smaller NS size (related to the proliferation and survival of the neural-progenitors) and a decreased capacity to form NS (self-renewal). The former seems to be the result of p53 compensatory activity, whereas the latter is p53 independent. We also demonstrate that p73 deficiency increases the population of neuronal progenitors ready to differentiate into neurons at the expense of depleting the pool of undifferentiated neurosphere-forming cells. Analysis of the neurogenic niches demonstrated that p73-loss depletes the number of neural-progenitor cells, rendering deficient niches in the adult mice. Altogether, our study identifies TP73 as a positive regulator of self-renewal with a role in the maintenance of the neurogenic capacity. Thus, proposing p73 as an important player in the development of neurodegenerative diseases and a potential therapeutic targetSILGC is beneficiary of a predoctoral fellowship from Consejo de Educación de la Junta de Castilla y León and RFA from Spanish Ministerio de Ciencia e Innovación. This work was supported by Grants SAF2009-07897 from Spanish Ministerio de Ciencia e Innovacion (to MCM), Grant from Cajas de Ahorro de Castilla y León (to MCM), and Grants LE030A07 (to MMM) and LE015A10-2 (to MCM) from the Junta de Castilla y Leó