Effects of Temperature, Nitrogen Fertilisation and Leaf and Tiller Age on Specific Leaf Area of \u3ci\u3eBrachiaria decumbens\u3c/i\u3e

Signal grass (Brachiaria decumbens Stapf) micro-swards were grown under controlled environmental conditions at different temperatures and nitrogen fertilisation rates. Specific leaf area was responsive both to temperature and nitrogen, but did not change with the level of insertion of the leaf in the tiller. Senescing leaves had higher specific leaf area than old extended green leaves and these had higher values than new extended green leaves. Changes in specific leaf area were more related to changes in leaf area and more exactly to changes in leaf width

Encapsulation and release mechanisms in coordination polymer nanoparticles

The interplay of guest encapsulation and release mechanisms in nanoscale metal-organic vehicles and its effect on the drug-delivery kinetics of these materials were investigated through a new multidisciplinary approach. Two rationally-designed molecular guests were synthesized, which consist of a red-fluorescent benzophenoxazine dye covalently tethered to a coordinating catechol group and a protected, non-coordinating catechol moiety. This allowed loading of the guests into compositionally and structurally equivalent coordination polymer particles through distinct encapsulation mechanisms: coordination and mechanical entrapment. The two types of particles delivered their fluorescent cargo with remarkably different kinetic profiles, which could be satisfactorily modeled considering degradation- and diffusion-controlled release processes. This demonstrates that careful selection of the method of guest incorporation into coordination polymer nanoparticles allows selective tuning of the rate of drug delivery from these materials and, therefore, of the time window of action of the encapsulated therapeutic agents. Drug-release mechanisms uncovered! Coordination polymer nanoparticles loaded with coordinated and mechanically entrapped fluorescent guests were prepared as benchmark systems to investigate diffusion- and degradation-controlled drug delivery from these materials (see figure)

Two-photon neuronal and astrocytic stimulation with azobenzene-based photoswitches

This is an open access article published under an ACS AuthorChoice License. See Standard ACS AuthorChoice/Editors' Choice Usage Agreement - https://pubs.acs.org/page/policy/authorchoice_termsofuse.htmlSynthetic photochromic compounds can be designed to control a variety of proteins and their biochemical functions in living cells, but the high spatiotemporal precision and tissue penetration of two-photon stimulation have never been investigated in these molecules. Here we demonstrate two-photon excitation of azobenzene-based protein switches and versatile strategies to enhance their photochemical responses. This enables new applications to control the activation of neurons and astrocytes with cellular and subcellular resolution

Predicting plant species distribution across an alpine rangeland in northern Spain. A comparison of probabilistic methods

18 páginas, 7 figuras, 5 tablas.-- El Pdf del artículo es la versión pre-print.[Question]: Predictive models constitute an important tool in multiple ecological applications. In this paper, we examine and compare the performance of six state-of-the-art methods commonly used in ecological modelling: Multiple Logistic Regression (MLR), Artificial Neural Networks (ANN), Support Vector Machines (SVM), Classification and Regression Trees (CART), Maximum Entropy (MAXENT) and Multivariate Adaptive Regression Splines (MARS). [Location]: Northern Spain. [Methods]: We used presence/absence data of 15 plant species of an alpine rangeland in northern Spain and 14 topographical and geomorphological descriptors to build the models. We used leave-one-out cross validation on each model and computed the area under the receiver operating characteristic (ROC) curve (AUC) and the resolution and calibration diagrams of the resulting probabilistic predictions. We also analysed the binary presence/absence deterministic predictions and computed the corresponding confusion matrices to calculate sensitivity, specificity, Cohen's kappa and the True Skill Statistic (TSS). [Results]: In general, CART and MAXENT showed poor performance and MLR was competitive with the more sophisticated ANN, MARS and SVM methods. The best predictive resolution was obtained, in most cases, by ANN followed by SVM and CART models; however, MLR and MARS were generally the best calibrated. The MAXENT predictions attained, in general, poor resolution and moderate to good calibration. [Conclusion]: Assessment of model calibration and resolution, in addition to ROC and confusion matrix-derived indices, is an important step for model choice depending on the final aim. Most of the target species were accurately predicted showing that the variables used are suitable descriptors at the scale of analysis.This work was supported by the Spanish Institute for Agricultural and Food Research and Technology [INIA, RTA2005-00160-C02-00].Peer reviewe

De la investigación a la práctica: herramientas para gestionar la ganadería de montaña y los pastos comunales de Cantabria dentro de la política agraria común = Science into practice: tools to manage mountain livestock systems and grazing commons of canta

La ganadería extensiva de montaña y los pastos comunales son recursos de gran impcrtancia socio-económica y ecológica en Cantabria y en otras regiones montañosas de Europa. Aún así, y a pesar de las exigencias normativas, es notoria la actual carencia de planes de gestión que aseguren un uso silvopastoral sostenible de los terrenos comunales. Resulta paradójico que la Política Agraria Común (PAC), fuente de ingresos más importante de las ganaderías extensivas y basada principalmente en pagos por superficie agraria, no considere explícitamente la necesidad de esta gestión en su apoyo económico a estos sistemas ganaderos. El próximo programa 2015-2020 de la PACen Cantabria centra buena parte de sus esfuerzos en pagar por el mantenimiento de pastos permanentes, con escasas exigencias sobre cómo hacerlo y con una definición de "pasto permanente" aún controvertida. Las medidas propuestas para este nuevo programa no favorecen la mejora de unos sistemas ganaderos de montaña en declive, siendo necesario considerar una visión sistémica que integre territorio y ganado en pastoreo a la escala de paisaje correcta. Desde el punto de vista técnico, es necesario disponer de herramientas que ayuden en este enfoque. En este sentido, se presenta el modelo de simulación PUERTO, que emula el funcionamiento del pastoreo en pastos comunales de montaña complejos, permitiendo evaluar si la utilización forrajera del territorio es sostenible para el pasto y los herbívoros. Este macelo se ha creado con el objetivo de servir como herramienta de apoyo a la gestión de estos sistemas, pudiendo, por tanto, ayudar desde la investigación a la construcción de una futura PAC que articule de forma más tangible sus objetivos de sostenibilidad de los agro-ecosistemas. Se presentan tres casos diferentes de aplicación del modelo PUERTO a situaciones de complejidad creciente para comprender su funcionamiento y su potencial utilidad práctica. En estos casos se muestra la capacidad del macelo de simular los efectos pracucidos pcr distintos escenarios de carga ganadera, ti pes de ganado en pastoreo o superficie de pasto mejorado, así como su utilidad en el diseño de instrumentos de gestión de montes comunales de gran superficie y con múltiples rebaños en pastoreo, a través de la interpretación de los resultados predichos sobre variación del peso de los animales y utilización forrajera de la vegetación en unidades territoriales del comunal bien definidas. ABSTRACT Extensive livestock farming and communal grazing land are important socio-economic and ecological resources in Cantabria and in other mountainous regions of Europe. However, and even with existing regulatory mandates, it is notorious the current lack of management plans to ensure sustainable silvopastoral use in these commons. It is paradoxical that the Common Agricultural Policy (CAP), which is the most important income source in extensive livestock farms, does not consider explicitly the need for these management plans in their support to these agricultural systems. The next 2015-2020 CAP program in Cantabria focuses most of its budget in paying farmers for the maintenance of permanent pastures, with few requirements on how to do it and even with a definition of what is “permanent pasture” which is still controversial. The proposed measures in this new program do not favour the improvement of these depressed mountain livestock farming systems, as it is still necessary to view them systemically, integrating land and livestock and at a correct landscape scale. From the technical point of view, there is a need to dispose of tools that can aid in this approach. One of these is the simulation model PUERTO, which is introduced in this contribution. PUERTO emulates the functioning of grazing in complex mountainous communal rangelands, allowing for the evaluation of forage utilisation sustainability both for the land and for the herbivores. This model was created with the main objective of serving as a decision support tool to the management of this type of systems, aiming to help in the long term to the construction of a future CAP which considers in a more tangible way its objectives of agro-ecosystems sustainability. Three different cases of application of the model PUERTO are presented, considering situations of increasing complexity to help in understanding how it works and its potentiality of use. These cases show the capacity of the model to simulate the effects of different scenarios of stocking rate, type of grazing livestock species or area of improved grassland. They also demonstrate the utility of PUERTO for the implementation of management planning in large commons with many grazing herds. This is performed interpreting the predicted outputs on animal weight changes and vegetation forage utilisation in well defined land units conforming the communal land

Productivity, grazing utilization, forage quality and primary production controls of species-rich alpine grasslands with Nardus stricta in northern Spain

Species-rich alpine grasslands with Nardus stricta are important communities for both animal production and environmental conservation in Europe. We selected two contrasting types of Nardus grasslands (mesic and wet) within a rangeland of northern Spain and measured annual above-ground net primary productivity (ANPP), botanical components, forage utilization and their respective seasonal patterns, during a 5-year period. We analysed their chemical properties and recorded soil moisture and temperature in order to construct models able to explain grassland productivity. Mean annual ANPP of mesic Nardus grassland was about half (216gDMm-2year-1; ±29·8s.e.) that of the wet grassland (406g DMm-2year-1; ±54·3s.e.), with significant intra- and interannual variability. Mesic grassland, with a more important contribution of forbs and legumes over graminoids in its botanical composition, was the preferred forage source of grazing livestock and showed better chemical properties in spring and early summer. In summer and autumn, wet grassland had a higher utilization owing to its ability to maintain high biomass production. This was partially explained by soil moisture, a limiting factor of mesic grassland productivity. Our results provide new and relevant information on key aspects of species-rich alpine Nardus grasslands, potentially useful for the definition of management options for these habitats of priority conservation. © 2012 Blackwell Publishing Ltd.Funded by: Spanish Institute for Agricultural and Food Research and Technology (INIA). Grant Number: RTA-2005-00160-C02-00.Peer Reviewe

Sward structure and patterns of defoliation of signal grass (Brachiaria decumbens) pastures under different cattle grazing intensities

The effects of 3 different stocking rates (1, 2 and 3 cows/ha/yr) on sward structure and the amount and pattern of live leaf defoliation were studied at different hierarchical levels within swards of signal grass (Brachiaria decumbens ) pastures. Permanently marked plants and tillers were followed non-destructively during 8 consecutive grazing periods for each stocking rate treatment. Leaf and stem lengths were measured before and after the introduction of cattle for all marked tillers. The vertical distribution of leaves and stems within the sward was quantified and the fate of tillers after grazing was also considered. Vertical live leaf weight distributions in the canopy followed those of their apical meristem heights. The proportion of tillers defoliated per plant mainly explained the proportion of live leaf defoliated per plant at different stocking rates. The proportion of tillers decapitated during grazing was related to the proportion of tillers defoliated per plant. Apical meristem height was the main physical barrier to leaf defoliation upon a minimum leaf height of 2–4 cm, under which leaves were inaccessible to cattle. Different stocking rates created different tiller heights and canopy structures in the medium term, but did not affect the pattern of defoliation relative to the height of the apical meristem