The Large Aperture GRB Observatory

The Large Aperture GRB Observatory (LAGO) is aiming at the detection of the high energy (around 100 GeV) component of Gamma Ray Bursts, using the single particle technique in arrays of Water Cherenkov Detectors (WCD) in high mountain sites (Chacaltaya, Bolivia, 5300 m a.s.l., Pico Espejo, Venezuela, 4750 m a.s.l., Sierra Negra, Mexico, 4650 m a.s.l). WCD at high altitude offer a unique possibility of detecting low gamma fluxes in the 10 GeV - 1 TeV range. The status of the Observatory and data collected from 2007 to date will be presented.Comment: 4 pages, proceeding of 31st ICRC 200

Water Cherenkov Detectors response to a Gamma Ray Burst in the Large Aperture GRB Observatory

In order to characterise the behaviour of Water Cherenkov Detectors (WCD) under a sudden increase of 1 GeV - 1 TeV background photons from a Gamma Ray Burst (GRB), simulations were conducted and compared to data acquired by the WCD of the Large Aperture GRB Observatory (LAGO). The LAGO operates arrays of WCD at high altitude to detect GRBs using the single particle technique. The LAGO sensitivity to GRBs is derived from the reported simulations of the gamma initiated particle showers in the atmosphere and the WCD response to secondaries.Comment: 5 pages, proceeding of the 31st ICRC 200

Multiple-constraint inversion of SCOPE. Evaluating the potential of GPP and SIF for the retrieval of plant functional traits

The most recent efforts to provide remote sensing (RS) estimates of plant function rely on the combination of Radiative Transfer Models (RTM) and Soil-Vegetation-Atmosphere Transfer (SVAT) models, such as the Soil-Canopy Observation Photosynthesis and Energy fluxes (SCOPE) model. In this work we used ground spectroradiometric and chamber-based CO2 flux measurements in a nutrient manipulated Mediterranean grassland in order to: 1) develop a multiple-constraint inversion approach of SCOPE able to retrieve vegetation biochemical, structural as well as key functional traits, such as chlorophyll concentration (Cab), leaf area index (LAI), maximum carboxylation rate (Vcmax) and the Ball-Berry sensitivity parameter (m); and 2) compare the potential of the of gross primary production (GPP) and sun-induced fluorescence (SIF), together with up-welling Thermal Infrared (TIR) radiance and optical reflectance factors (RF), to estimate such parameters. The performance of the proposed inversion method as well as of the different sets of constraints was assessed with contemporary measurements of water and heat fluxes and leaf nitrogen content, using pattern-oriented model evaluation. The multiple-constraint inversion approach proposed together with the combination of optical RF and diel GPP and TIR data provided reliable estimates of parameters, and improved predicted water and heat fluxes. The addition of SIF to this scheme slightly improved the estimation of m. Parameter estimates were coherent with the variability imposed by the fertilization and the seasonality of the grassland. Results revealed that fertilization had an impact on Vcmax, while no significant differences were found for m. The combination of RF, SIF and diel TIR data weakly constrained functional traits. Approaches not including GPP failed to estimate LAI; however GPP overestimated Cab in the dry period. These problems might be related to the presence of high fractions of senescent leaves in the grassland. The proposed inversion approach together with pattern-oriented model evaluation open new perspectives for the retrieval of plant functional traits relevant for land surface models, and can be utilized at various research sites where hyperspectral remote sensing imagery and eddy covariance flux measurements are simultaneously taken

Perspectivas sobre la evolución del agro argentino y pampeano del siglo XXI

El sector agropecuario argentino, presenta diversas aristas que hacen necesario un análisis complejo de su dinámica en el tiempo y en el territorio. El Censo Nacional Agropecuario del año 2002 fue hasta hace poco tiempo la referencia numérica cuantitativa del sector, ineludible por su rigurosidad. En el año 2008, en el contexto de una crisis sectorial entre parte del sector agropecuario y el Gobierno Nacional, se desarrolló con inconvenientes operativos y metodológicos un nuevo censo. Aquí un punto y seguido. El cual no pudo utilizarse siendo una pérdida de recursos y de tiempo. Recién en 2018 se logró concretar un proceso censal de calidad, que captó una nueva foto del sector. Los datos preliminares permiten comenzar a analizar las principales evoluciones en estos últimos 16 años. El objetivo del presente trabajo es sumar perspectivas y preguntas e interrogantes sobre las evoluciones de indicadores sociales, productivos, ambientales e institucionales que se desprenden de la comparación del Censo Nacional Agropecuario 2002 y el 2018 en Argentina en general y en La Pampa en particular.Fil: Ferro Moreno, Santiago. Instituto Nacional de Tecnología Agropecuaria. Centro Regional La Pampa-San Luis. Estación Experimental Agropecuaria Anguil; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis; ArgentinaFil: Perez, S.. Universidad Nacional de La Pampa; ArgentinaFil: Mariano, R.. Universidad Nacional de La Pampa; ArgentinaFil: Murcia, M.. Universidad Nacional de La Pampa; ArgentinaFil: Prieto, R.. Universidad Nacional de La Pampa; ArgentinaFil: Carassay, Luciano Raul. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Fitopatología y Fisiología Vegetal; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Folmer, O.. Universidad Nacional de La Pampa; Argentin

Formación de callos en Anthurium magnificum Linden

Anthurium magnificum Linden is a very popular ornamental plant due to its beautiful foliage. In this species, traditional propagation methods are not practical for its large-scale production, and there are no studies in the scientific literature on its in vitro culture. The objective of this work was to achieve the formation of callus in Anthurium magnificum Linden. For this, the effect of different concentrations of 2,4-D and two types of explant (leaf sections and petiole sections) was evaluated. The results showed that the highest percentages of callus formation were obtained in the petiole sections with 100% in all treatments. The foliar sections showed lower percentages of callus formation in relation to the petiole. The callus formed from both explants were translucent, with a watery appearance and a yellowish-white color, characteristics that are evidence of non-regenerable callus. However, plants were regenerated from callus formed from petioles sections. It was shown that it is possible to form callus in this species. In this sense, the highest percentage and growth of callus were reached when sections of petioles and 0.3 mg l-1 2,4-D in the culture medium were used. This research constitutes the first scientific report on the in vitro culture of this species.Anthurium magnificum Linden es una planta ornamental con gran popularidad debido a su hermoso follaje. En esta especie los métodos de propagación tradicionales no resultan prácticos para su producción a gran escala, y no se encuentran estudios en la literatura científica sobre su cultivo in vitro. Este trabajo tuvo como objetivo lograr la formación de callos en Anthurium magnificum Linden. Para ello, se evaluó el efecto de diferentes concentraciones de 2,4-D y dos tipos de explante (secciones foliares y secciones de pecíolos). Los resultados mostraron que los mayores porcentajes de formación de callos se obtuvieron en las secciones de pecíolos con un 100% en todos los tratamientos. Las secciones foliares mostraron menores porcentajes de formación de callos en relación con el pecíolo. Los callos formados a partir de ambos explantes fueron traslúcidos, de apariencia acuosa y coloración blanco-amarillenta, característica que son evidencia de callos no regenerables. No obstante, los callos formados a partir de secciones de pecíolos lograron regenerar plantas. Se demostró que es posible formar callos en esta especie. En este sentido, el mayor porcentaje y crecimiento de los callos se alcanzó cuando se emplearon secciones de pecíolos y 0.3 mg l-1 de 2,4-D en el medio de cultivo. Esta investigación constituye el primer informe científico sobre el cultivo in vitro de esta especie

Callus formation inAnthurium magnificum Linden

Anthurium magnificum Linden is a very popular ornamental plant due to its beautiful foliage.In this species, traditional propagation methods are not practical for its large-scale production,and there are no studies in the scientific literature on itsin vitro culture. The objective ofthis work was to achieve the formation of callus inAnthurium magnificum Linden. For this,the effect of different concentrations of 2,4-D and two types of explant (leaf sections andpetiole sections) was evaluated. The results showed that the highest percentages ofcallus formation were obtained in the petiole sections with 100% in all treatments. Thefoliar sections showed lower percentages of callus formation in relation to the petiole. Thecallus formed from both explants were translucent, with a watery appearance and ayellowish-white color, characteristics that are evidence of non-regenerable callus. However,plants were regenerated from callus formed from petioles sections. It was shown that it ispossible to form callus in this species. In this sense, the highest percentage and growth ofcallus were reached when sections of petioles and 0.3 mg l-1 2,4-D in the culture mediumwere used. This research constitutes the first scientific report on thein vitro culture ofthis specie

How nitrogen and phosphorus availability change water use efficiency in a Mediterranean savanna ecosystem

Nutrient availability, especially of nitrogen (N) and phosphorus (P), is of major importance for every organism and at a larger scale for ecosystem functioning and productivity. Changes in nutrient availability and potential stoichiometric imbalance due to anthropogenic nitrogen deposition might lead to nutrient deficiency or alter ecosystem functioning in various ways. In this study, we present 6 years (2014–2020) of flux-, plant-, and remote sensing data from a large-scale nutrient manipulation experiment conducted in a Mediterranean savanna-type ecosystem with an emphasis on the effects of N and P treatments on ecosystem-scale water-use efficiency (WUE) and related mechanisms. Two plots were fertilized with N (NT, 16.9 Ha) and N + P (NPT, 21.5 Ha), and a third unfertilized plot served as a control (CT). Fertilization had a strong impact on leaf nutrient stoichiometry only within the herbaceous layer with increased leaf N in both fertilized treatments and increased leaf P in NPT. Following fertilization, WUE in NT and NPT increased during the peak of growing season. While gross primary productivity similarly increased in NT and NPT, transpiration and surface conductance increased more in NT than in NPT. The results show that the NPT plot with higher nutrient availability, but more balanced N:P leaf stoichiometry had the highest WUE. On average, higher N availability resulted in a 40% increased leaf area index (LAI) in both fertilized treatments in the spring. Increased LAI reduced aerodynamic conductance and thus evaporation at both fertilized plots in the spring. Despite reduced evaporation, annual evapotranspiration increased by 10% (48.6 ± 28.3 kg H2O m−2), in the NT plot, while NPT remained similar to CT (−1%, −6.7 ± 12.2 kgH2O m−2). Potential causes for increased transpiration at NT could be increased root biomass and thus higher water uptake or rhizosphere priming to increase P-mobilization through microbes. The annual net ecosystem exchange shifted from a carbon source in CT (75.0 ± 20.6 gC m−2) to carbon-neutral in both fertilized treatments [−7.0 ± 18.5 gC m−2 (NT) 0.4 ± 22.6 gC m−2 (NPT)]. Our results show, that the N:P stoichiometric imbalance, resulting from N addition (without P), increases the WUE less than the addition of N + P, due to the strong increase in transpiration at NT, which indicates the importance of a balanced N and P content for WUE