Probing H2 autoionizing states with femto and attosecond laser pulses.

ABSTRACT: We show the relevance that molecular autoionizing states display in some recent experiments related to the symmetry-breaking in molecular-frame photoelectron angular distributions in H2 when exposed to intense xuv femtosecond laser pulses, and others related to the electron (proton) localization when subject to attosecond pump-probe laser schemes. Our theoretical method solves the time-dependent Schr¨odinger equation with an spectral method that expands the wave function in terms of H2 correlated stationary vibronic states including all electronic and vibrational degrees of motion. Time-resolved asymmetric electron angular distributions are obtained at specific proton kinetic energies due to the delayed autoionization from H2 doubly excited states, which induces interferences between gerade (1s(sigma)g) and ungerade (2p(sigma)u) ionization channels. We also study photoionization of H2 exposed to a xuv attosecond pump pulse plus a time-delayed IR femtosecond probe pulse. Fast alternating asymmetries in the proton ejection (electron localization) are obtained as a function of the time delay between the pump and the probe pulses. Finally, we deal with the process of (xuv) two-photon double ionization of H2 under the assumption of having both sequential and non-sequential absorption processes

Updating the distribution of Dicrodon guttulatum Duméril & Bibron, 1839 (Reptilia, Teiidae) with a disjunct population in the eastern slope of the Peruvian Andes

We report a disjunct population of Dicrodon guttulatum Duméril & Bibron, 1839 on the eastern slope of the Cordillera Occidental in the inter-Andean Seasonally Dry Forests of the Marañón River, in the Departments of Cajamarca and Piura in northwestern Peru. We include an updated range distribution map using records from museum specimens, the Global Biodiversity Information Facility, and available photographic records on iNaturalist. In addition, we identify widespread cultivation of rice crops as the main threat to D. guttulatum in the inter-Andean Seasonally Dry Forests of the Marañón

Effects of Milled Maize Stalks on the Productive Response of Grazing Dairy Cows.

The productive response of grazing dairy cows was evaluated, using milled corn stalks in the diet. The study was developed in two different settings, in Ecuador (Costa and Sierra regions). On the coast farm (29.1 ha), cows grazed on Bermuda grass (Cynodon nlemfuensis) and Guinea grass (Panicum maximum) with several types of legumes (Lysicarpus, Centrosema, Desmodium, Galactia), supplemented with corn stalks cv. INIAP 125. The animals received 0.46 kg beginning at 3 kg, and milled maize stalks in 30 and 28-day periods, respectively (M-30 and M-28), and control without stalks for 36 days (M-0). The farm in the other region (14.2 ha) had 23 cows grazing on Kikuyo grass (P. clandestinum) and ryegrass-white clover (L. perenne and whole maize stalks and T. (60-70% ripe grain), at a rate of 18 kg green/cow/day for 48 days; and balanced supplement, at a rate of 0.5 kg/ milk liter, after the fourth kilogram, along with minerals. In both cases the forage had effects (P < 0.05) on cow response. In the Sierra area, the increase was 1.68 kg/cow, and in the coast, it was 1.1 and 2.5 kg/cow). Maize stalks served as a nutritional complement for poorly consumed grass areas in both regions; milk production/animal was increased, and the costs were reduced

Sequential and direct two-photon double ionization of D2 at FLASH

ABSTRACT: Sequential and direct two-photon double ionization (DI) of D2 molecule is studied experimentally and theoretically at a photon energy of 38.8 eV. Experimental and theoretical kinetic energy releases of D++D+ fragments, consisting of the contributions of sequential DI via the D2+(1ssg) state and direct DI via a virtual state, agree well with each other

Sequential versus nonsequential two-photon double ionization of the D2 molecule at 38 eV

ABSTRACT: A simple theoretical model is used to interpret recent experimental results for two-photon double ionization (DI) of D2 at 38 eV. We show that the measured kinetic energy distribution associated with emission of two protons can be interpreted as a sum of two processes: a sequential and an instantaneous absorption of the two incident photons. These processes lead to peaks in di erent regions of the spaectrum

Humic Substances Enhance Chlorothalonil Phototransformation via Photoreduction and Energy Transfer

ABSTRACT: The photodegradation of chlorothalonil, a polychlorinated aromatic fungicide widely used in agriculture, was investigated under ultraviolet–visible irradiation in the presence and absence of different humic substances that significantly enhance the chlorothalonil phototransformation. On the basis of a kinetic model, an analytical study, the effect of scavengers, the chlorothalonil phosphorescence measurement, and varying irradiation conditions, it was possible to demonstrate that this accelerating effect is due to their capacity to reduce the chlorothalonil triplet state via H-donor reaction and to energy transfer from the triplet humic to ground state chlorothalonil. Energy transfer occurs at wavelengths below 450 nm and accounts for up to 30% of the reaction in deoxygenated medium upon irradiation with polychromatic light (300–450 nm). This process is more important with Elliott humic and fulvic acids and with humic acids extracted from natural carbonaceous material than with Nordic NOM and Pahokee peat humic acids. The obtained results are of high relevance to understanding the processes involved in chlorothalonil phototransformation and the photoreactivity of humic substances. Chlorothalonil is one of the rare molecules shown to react by energy transfer from excited humic substances

Efecto de la inclusión del forraje de maíz molido en la respuesta productiva de vacas lecheras en pastoreo.

Se evaluó la respuesta productiva de vacas lecheras en pastoreo al incluir forraje de maíz molido en su dieta. El estudio se realizó en dos ambientes diferentes de Ecuador (Región Costa y Sierra). En la costa, en una finca de 29,1 ha,las vacas pastaron asociaciones de estrella (Cynodon nlemfuensis) y saboya (Panicum máximum) con leguminosas devarios géneros como Alysicarpus, Centrosema, Desmodium, Galactia, suple-mentadas con forraje de maíz cv. INIAP 125. Los animales recibieron 0,46 kg a partir del tercer kilogramo, y forraje de maíz molido en períodos de 30 y 28 días, respectivamente (M-30 y M-28) y control sin forraje por 36 días (M-0). En la otra región, la propiedad tenía 14,2 ha y 23 vacas en ordeño; estas pastaron asociaciones de kikuyo (P. clandestinum) y ryegra-sstrébol blanco (L. perenne y T. repens) y forraje de maíz planta completa (60 a 70 % grano maduro), a razón de 18 kg verde/vaca/día durante 48 días, y balanceado a razón de 0,5 kg/l de leche después del cuarto kilogramo y minerales. El forraje influyó en ambos casos (P < 0,05) en la respuesta de las vacas; para la zona de la sierra el incremento fue de 1,68 kg/vaca de aumento en la leche y en la costa el aumento fue entre 1,1 y 2,5 kg/vaca. El forraje de maíz complementó nutri-cionalmente las asociaciones bajo pastoreo en ambas regiones, incrementó el rendimiento lechero/animal y redujo los costos.Effect of Ground CornStalks on the Productive Response of Dairy Grazing Cows ABSTRACTThe productive response of dairy grazing cows using ground cornstalks was assessed. The study was developed in two different Ecuadoran settings (Costa Region and Sierra). At the Costa, on a 29.1 ha farm, the cows grazed on star clusters (Cynodon nlemfuensis) and panic grass(Panicum máximum), with legumes of different genera, such as Alysicarpus, Centrosema, Desmodium, Galactia, supplemented with corn stalks, cv. INIAP 125. The animals received 0.46 kg from the third kg onward, and ground corn stalks in 30- and 28- day periods, respectively (M-30 and M-28), and a control group without stalks for 36 days (M-0). In another region, the estate had 14.2 ha and 23 milking cows, grazing on clusters of West African pennisetum (P. clandestinum) and ryegrass white clover (L. perenne and T. repens) and whole corn stalks (60 -70 % ripe grain), at a ratio of 18 kg green/cow/day for 48 days and balanced at a ratio of 0.5 kg/l of milk following the fourth kilogram, and minerals. In both cases, stalks effected (P < 0.05) on cow response. In the Sierra region, the milk yield increase observed was 1.68 kg/cow, and in the Costa region, it was between 1.1 and 2.5 kg/cow. Corn stalks meant nutritional supplementation to grazing clusters in both regions, increased milk/animal yields, and cost reductions

A new data-driven map predicts substantial undocumented peatland areas in Amazonia

Tropical peatlands are among the most carbon-dense terrestrial ecosystems yet recorded. Collectively, they comprise a large but highly uncertain reservoir of the global carbon cycle, with wide-ranging estimates of their global area (441 025–1700 000 km2) and below-ground carbon storage (105–288 Pg C). Substantial gaps remain in our understanding of peatland distribution in some key regions, including most of tropical South America. Here we compile 2413 ground reference points in and around Amazonian peatlands and use them alongside a stack of remote sensing products in a random forest model to generate the first field-data-driven model of peatland distribution across the Amazon basin. Our model predicts a total Amazonian peatland extent of 251 015 km$^2$ (95th percentile confidence interval: 128 671–373 359), greater than that of the Congo basin, but around 30% smaller than a recent model-derived estimate of peatland area across Amazonia. The model performs relatively well against point observations but spatial gaps in the ground reference dataset mean that model uncertainty remains high, particularly in parts of Brazil and Bolivia. For example, we predict significant peatland areas in northern Peru with relatively high confidence, while peatland areas in the Rio Negro basin and adjacent south-western Orinoco basin which have previously been predicted to hold Campinarana or white sand forests, are predicted with greater uncertainty. Similarly, we predict large areas of peatlands in Bolivia, surprisingly given the strong climatic seasonality found over most of the country. Very little field data exists with which to quantitatively assess the accuracy of our map in these regions. Data gaps such as these should be a high priority for new field sampling. This new map can facilitate future research into the vulnerability of peatlands to climate change and anthropogenic impacts, which is likely to vary spatially across the Amazon basin

Documento en extenso que incluye los resultados de la revisión de información secundaria y la obtenida en el taller con actores regionales, con la identificación de vacíos de información y prioridades de investigación y monitoreo en la cuenca del rió claro

En el marco del convenio de cooperación técnica y científica No. 19-100, celebrado entre la Fundación Grupo Argos y el Instituto de Investigación de Recursos Biológicos Alexander von Humboldt, con el objeto de aunar esfuerzos administrativos, técnicos, financieros y de gestión para la generación de conocimiento útil en escenarios de evaluación y manejo integral de impactos sobre la biodiversidad, desde una mirada ecosistémica integral del territorio de la cuenca del río Claro (Antioquia) en los múltiples contextos socioecológicos, se ha comprometido la construcción de la línea base de información secundaria disponible sobre biodiversidad para la cuenca del río Claro, Antioquia, que incluya, entre otros, datos sobre ecología, genética, uso, conservación, distribución, uso de hábitat, impactos e información espacial, procesos ecológicos.BogotáCiencias Básicas de la Biodiversida