Evaluaci?n de la huella h?drica de los sistemas de producci?n agr?cola y pecuario predominantes en la microcuenca la plata, (Ibagu?, Tolima)

116 p. Recurso Electr?nicoLa microcuenca La Plata tributa sus aguas a la cuenca del r?o Combeima, quien abastece agua para el acueducto de Ibagu? (Tolima). La microcuenca cuenta con un ?rea de 2.498 ha, el 86,66% de su cobertura es bosque natural, 7,5% cultivos, 5,75% pastos y 0,15% zonas improductivas. Las actividades productivas han provocado deforestaci?n, aumento en la erosi?n y han alterado la calidad y disponibilidad del agua. A pesar de estas condiciones, no se han definido indicadores de sostenibilidad para el manejo del recurso h?drico en la zona. Por tanto, este trabajo evalua la Huella H?drica (HH) de los sistemas de producci?n agr?cola predominantes en la microcuenca durante el a?o 2015, con el fin de establecer las relaciones causa-efecto a nivel socio-ambiental e indicadores para el manejo sostenible del recurso h?drico. Se calcularon las HH Azul (HA), Verde (HV) y Gris (HG) de los sistemas de producci?n. Los resultados indicaron que la HH de los sistemas de producci?n agr?cola es de 6.628,64 m3.t-1. El Caf? (Coffea arabica Linneo) es el que genera mayor HV. El sistema de producci?n que mayor HG produce es el de Mora (Rubus glaucus Benth). Adem?s, el an?lisis de sostenibilidad evidenci? que la microcuenca presenta un estado cr?tico o ?hotspot? ambiental por competencia de agua verde. Los resultados e indicadores permitieron crear estrategias de respuesta para mejorar la oferta, demanda y calidad del recurso h?drico, con el ?nimo de contribuir a su uso eficiente. Este trabajo recibi? apoyo econ?mico del proyecto ?EOCYT? de la Universidad del Tolima. Palabras claves: Huella H?drica Azul, Huella H?drica Verde, Huella H?drica Gris.The Plata micro-watershed tributes its waters to the Combeima river basin, which supplies water to the Ibagu? aqueduct (Tolima). The microbasin has an area of 2,498 ha, 86.66% of its coverage is natural forest, 7.5% crops, 5.75% pastures and 0.15% unproductive areas. Productive activities have caused deforestation, increased erosion and have altered the quality and availability of water. Despite these conditions, no sustainability indicators have been defined for the management of water resources in the area. Therefore, this work evaluates the Water Footprint (HH) of the predominant agricultural production systems in the microbasin during 2015, in order to establish cause-effect relationships at the socio-environmental level and indicators for the sustainable management of the resource. water HH Blue (HA), Green (HV) and Gray (HG) of the production systems were calculated. The results indicated that the HH of the agricultural production systems is 6,628.64 m3.t-1. Coffee (Coffea arabica Linneo) is the one that generates the highest HV. The production system that produces the most HG is Mora (Rubus glaucus Benth). In addition, the sustainability analysis showed that the microbasin presents a critical state or environmental "hotspot" due to green water competition. The results and indicators allowed to create response strategies to improve the supply, demand and quality of the water resource, with the aim of contributing to its efficient use. This work received financial support from the "EOCYT" project of the Universidad del Tolima.. Keywords: Blue Water Footprint, Green Water Footprint, Gray Water Footprin

Scale Effects on the Ballistic Penetration of Graphene Sheets

AbstractCarbon nanostructures are promising ballistic protection materials, due to their low density and excellent mechanical properties. Recent experimental and computational investigations on the behavior of graphene under impact conditions revealed exceptional energy absorption properties as well. However, the reported numerical and experimental values differ by an order of magnitude. In this work, we combined numerical and analytical modeling to address this issue. In the numerical part, we employed reactive molecular dynamics to carry out ballistic tests on single, double, and triple-layered graphene sheets. We used velocity values within the range tested in experiments. Our numerical and the experimental results were used to determine parameters for a scaling law. We find that the specific penetration energy decreases as the number of layers (N) increases, from ∼15 MJ/kg for N = 1 to ∼0.9 MJ/kg for N = 350, for an impact velocity of 900 m/s. These values are in good agreement with simulations and experiments, within the entire range of N values for which data is presently available. Scale effects explain the apparent discrepancy between simulations and experiments.</jats:p

Delimiting floristic biogeographic districts in the Cerrado and assessing their conservation status

This is the author accepted manuscript. The final version is available from Springer via the DOI in this recordThe Cerrado is a biodiversity hotspot in central Brazil that represents the largest expanse of savanna in the Neotropics. Here, we aim to identify and delimit biogeographic districts within the Cerrado, to provide a geographic framework for conservation planning and scientific research prioritisation. We used data from 588 sites with tree species inventories distributed across the entire Cerrado. To identify districts, we clustered sites based on their similarity in tree species composition. To investigate why districts differ in composition, we 1) determined the proportion of tree species in different districts that derive from other biomes, to assess the influence of neighbouring biomes upon geographically marginal districts and 2) assayed key climatic differences between districts, to test the effect of environmental factors upon compositional differences. We found seven biogeographic districts within the Cerrado. Marginal districts have a large proportion of tree species characteristic of Amazonia and Atlantic Forest, but the Cerrado endemic species are also important. Further, districts differed significantly for multiple climatic variables. Finally, to provide a preliminary conservation assessment of the different districts, we assessed their rate of land conversion and current coverage by protected areas. We found that districts in the south and southwest of the Cerrado have experienced the greatest land conversion and are the least protected, while those in the north and northeast are less impacted and better protected. Overall, our results show how biogeographic analyses can contribute to conservation planning by giving clear guidelines on which districts merit greater conservation and management attention.Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorConselho Nacional de Desenvolvimento Científico e Tecnológic

The value of subtraction MRI in detection of amyloid-related imaging abnormalities with oedema or effusion in Alzheimer's patients: An interobserver study

BACKGROUND: Immunotherapeutic treatments targeting amyloid-β plaques in Alzheimer's disease (AD) are associated with the presence of amyloid-related imaging abnormalities with oedema or effusion (ARIA-E), whose detection and classification is crucial to evaluate subjects enrolled in clinical trials. PURPOSE: To investigate the applicability of subtraction MRI in the ARIA-E detection using an established ARIA-E-rating scale. METHODS: We included 75 AD patients receiving bapineuzumab treatment, including 29 ARIA-E cases. Five neuroradiologists rated their brain MRI-scans with and without subtraction images. The accuracy of evaluating the presence of ARIA-E, intraclass correlation coefficient (ICC) and specific agreement was calculated. RESULTS: Subtraction resulted in higher sensitivity (0.966) and lower specificity (0.970) than native images (0.959, 0.991, respectively). Individual rater detection was excellent. ICC scores ranged from excellent to good, except for gyral swelling (moderate). Excellent negative and good positive specific agreement among all ARIA-E imaging features was reported in both groups. Combining sulcal hyperintensity and gyral swelling significantly increased positive agreement for subtraction images. CONCLUSION: Subtraction MRI has potential as a visual aid increasing the sensitivity of ARIA-E assessment. However, in order to improve its usefulness isotropic acquisition and enhanced training are required. The ARIA-E rating scale may benefit from combining sulcal hyperintensity and swelling. KEY POINTS: • Subtraction technique can improve detection amyloid-related imaging-abnormalities with edema/effusion in Alzheimer's patients. • The value of ARIA-E detection, classification and monitoring using subtraction was assessed. • Validation of an established ARIA-E rating scale, recommendations for improvement are reported. • Complementary statistical methods were employed to measure accuracy, inter-rater-reliability and specific agreement