Experimental analysis of drainage and water storage of litter layers

International audienceMany hydrological studies of forested ecosystems focus on the study of the forest canopy and have partitioned gross precipitation into throughfall and stemflow. However, the presence of forest litter can alter the quantities of water available for soil infiltration and runoff. Little information exists regarding the value of storage and drainage parameters for litter layers. Vegetation parameters of this kind are required in physically-based and lumped conceptual models to quatify the availabilty and distribution of water. Using a rainfall simulator and laboratory conditions two main objectives were investigated using layers of recently seneced poplar leaves, fresh grass or woodchips: 1) Effect of rain intensity on storage. With this respect we found that: maximum storage (Cmax), defined as the detention of water immediately before rainfall cessation, increased with rainfall intensity. The magnitude of the increment was up to 0.5 mm kg?1 m?2 between the lowest (9.8 mm h?1) and highest (70.9 mm h?1) rainfall intensities for poplar leaves. Minimum storage (Cmin), defined as the detention of water after drainage ceased, was not influenced by rainfall intensity. Repeated wetting-draining cycles or layer thickness have no effect on Cmax or Cmin. 2) The evaluation of drainage coefficient for the Rutter model. This model was found accurate to predict storage and drainage in the case of poplar leaves, was less accurate for fresh grass and resulted in overestimations for woodchips. Additionally, the effect of an underlaying soil matrix on lateral movement of water and storage of poplar leaves was studied. Results indicated that the soil matrix have no effect on Cmax or Cmin of the litter layer. Lateral movement of water in the poplar layer was observed at intermediate rainfall intensities (30.2 and 40.4 mm h?1), but not a the lowest or highest rates

Capacitively Coupled Electrical Stimulation of Rat Chondroepiphysis Explants: A Histomorphometric Analysis

[EN] The growth plate is a cartilaginous layer present from the gestation period until the end of puberty where it ossifies joining diaphysis and epiphysis. During this period several endocrine, autocrine, and paracrine processes within the growth plate are carried out by chondrocytes; therefore, a disruption in cellular functions may lead to pathologies affecting bone development. It is known that electric fields impact the growth plate; however, parameters such as stimulation time and electric field intensity are not well documented. Accordingly, this study presents a histomorphometrical framework to assess the effect of electric fields on chondroepiphysis ex-plants. Bones were stimulated with 3.5 and 7 mV/cm, and for each electric field two exposure times were tested for 30 days (30 min and 1 h). Results evidenced that electric fields increased the hypertrophic zones compared with controls. In addition, a stimulation of 3.5 mV/cm applied for 1 h preserved the columnar cell density and its orientation. Moreover, a pre-hypertrophy differentiation in the center of the chondroepiphysis was observed when explants were stimulated during 1 h with both electric fields. These findings allow the understanding of the effect of electrical stimulation over growth plate organization and how the stimulation modifies chondrocytes morphophysiology.This research was supported by COLCIENCIAS Administrative Department of Science, Technology and Innovation. The authors gratefully thank the research support from the Biotechnology Institute of the Universidad Nacional de Colombia, for providing the lab space at the Biomimetics Laboratory and the reactants to perform the experimental approach of this study. Research reported in this publication was supported by COLCIENCIAS Administrative Department of Science, Technology and Innovation (Announcement 712-2015 Grant No 50457).Vaca-González, JJ.; Escobar, J.; Guevara, J.; Hata, YA.; Gallego Ferrer, G.; Garzón-Alvarado, DA. (2019). Capacitively Coupled Electrical Stimulation of Rat Chondroepiphysis Explants: A Histomorphometric Analysis. Bioelectrochemistry. 126:1-11. https://doi.org/10.1016/j.bioelechem.2018.11.004S11112

Fog interception by Ball moss (<i>Tillandsia recurvata</i>)

Interception losses are a major influence in the water yield of vegetated areas. For most storms, rain interception results in less water reaching the ground. However, fog interception can increase the overall water storage capacity of the vegetation and once the storage is exceeded, fog drip is a common hydrological input. Fog interception is disregarded in water budgets of semiarid regions, but for some plant communities, it could be a mechanism offsetting evaporation losses. <i>Tillandsia recurvata</i> is a cosmopolitan epiphyte adapted to arid habitats where fog may be an important water source. Therefore, the interception storage capacity by <i>T. recurvata</i> was measured in controlled conditions and applying simulated rain or fog. Juvenile, vegetative specimens were used to determine the potential upperbound storage capacities. The storage capacity was proportional to dry weight mass. Interception storage capacity (<i>C</i>_min) was 0.19 and 0.56 mm for rainfall and fog respectively. The coefficients obtained in the laboratory were used together with biomass measurements for <i>T. recurvata</i> in a xeric scrub to calculate the depth of water intercepted by rain. <i>T. recurvata</i> contributed 20 % to the rain interception capacity of their shrub hosts: <i>Acacia farnesiana</i> and <i>Prosopis laevigata</i> and; also potentially intercepted 4.8 % of the annual rainfall. Nocturnal stomatic opening in <i>T. recurvata</i> is not only relevant for CO₂ but for water vapor, as suggested by the higher weight change of specimens wetted with fog for 1 h at dark in comparison to those wetted during daylight (543 ± 77 vs. 325 ± 56 mg, <i>p</i> = 0.048). The storage capacity of <i>T. recurvata</i> leaf surfaces could increase the amount of water available for evaporation, but as this species colonise montane forests, the effect could be negative on water recharge, because potential storage capacity is very high, in the laboratory experiments it took up to 12 h at a rate of 0.26 l h⁻¹ to reach saturation conditions when fog was applied

Diseño de una red de sensores inalámbricos para el despliegue óptimo de los nodos sensores en un cultivo de Cacao

In this study, factorial experiments were conducted in two different scenarios to design a Wireless Sensor Network for monitoring a cocoa crop in a rural area in Colombia. Node sensors measured temperature, relative humidity, soil moisture, Ultra-Violet light, and visible light intensity. The factors considered in the experiments were distance between node sensors, height from the ground, and type of antenna; in turn, Received Signal Strength Indicator and data transfer time were the outputs. The wireless sensor network was deployed in the crop, covering approximately 3 % of the area and using 7 different nodes in a cluster tree topology. First, an open field scenario with line of sight was used to determine the appropriate height of the node sensors. Second, a scenario in the actual cocoa crop was utilized to find the appropriate distance between modules and type of antenna. We found, based on our calculations and experimental data, that a height of 1.25 m was required to avoid the Fresnel zone and improve the RSSI of the network. Furthermore, we determined that a distance below 35 m was needed to guarantee signal reception and avoid long data transfer times. The wire antenna exhibited a better performance. Finally, the proposed methodology and monitoring system can be used for agronomic applications in rural areas in Colombia to increase crop yield.En este trabajo se realizaron experimentos factoriales en dos escenarios diferentes, para diseñar una red de sensores inalámbricos, que permita monitorear un cultivo de cacao en una zona rural de Colombia. Los nodos sensores miden la temperatura, la humedad relativa, la humedad del suelo, la luz ultravioleta y la intensidad de la luz visible. Los factores considerados en los experimentos fueron la distancia entre los nodos sensores, la altura con respecto al suelo y el tipo de antena; el indicador de intensidad de señal recibida y el tiempo de transferencia de datos fueron las salidas. La red de sensores inalámbricos se implementó en el cultivo, cubriendo aproximadamente el 3 % del área, utilizando 7 nodos diferentes en una topología de cluster-tree. En primer lugar, se utilizó un escenario de campo abierto con línea de vista para determinar la altura adecuada de los sensores de nodo. Luego, se utilizó un escenario en el cultivo de cacao real para encontrar la distancia adecuada entre los módulos y el tipo de antena. Se obtuvo, por cálculos y datos experimentales, que se requería una altura de 1.25 m para evitar la zona de Fresnel y mejorar el RSSI de la red. Además, se determinó que se necesitaba una distancia inferior a 35 m para garantizar la recepción de la señal y evitar largos tiempos de transferencia de datos. Adicionalmente, la antena tipo Wire exhibió un mayor rendimiento y la metodología propuesta y el sistema de monitoreo se pueden usar para aplicaciones agronómicas en áreas rurales de Colombia, con el fin de aumentar el rendimiento de los cultivos

MicroRNAs Sequencing for Understanding the Genetic Regulation of Plant Genomes

MicroRNAs (miRNAs) are endogenous non-coding RNAs that play important regulatory roles in animals and plants by targeting mRNAs for cleavage or translational repression. Small RNAs are classified into different types by their biogenesis and mode of action, such as miRNAs, siRNAs, piRNAs, and snoRNAs. In the case of miRNAs, this specific type regulates gene expression in plants and animals by targeting mRNAs for cleavage and translational repression, respectively. Diverse miRNAs regulate plant development, metabolism, and responses to biotic and abiotic stresses. The identification of miRNAs has been accomplished in diverse species, organs and developmental or diverse biotic and abiotic stress conditions. Novel massive sequencing techniques and further bioinformatics analysis have allowed the identification of hundreds of miRNAs in Arabidopsis thaliana, Oryza sativa, Malus domestica, Zea mays, Solanum lycopersicum, and other plants. Functional characterization of a given miRNA in a specific biological context has shown their role in the fine-tuning mechanisms of posttranscriptional gene regulation. In this chapter, besides making a summary of genome-wide miRNA profiling in plants, we describe how gain and loss of function approaches influence plant phenotypes that affect development, physiology or stress responses, pointing to miRNAs as effective tools for the generation of new plant phenotypes that improve plant productivity and conservation

Proyecto Especial T?nel Trasandino para Trasvase de Agua ? PET 2

El presente trabajo de investigaci?n, es el desarrollo de la planificaci?n y la aprobaci?n del Plan para la Direcci?n del Proyecto Especial T?nel Trasandino para Trasvase de Agua - PET 2, tomando en cuenta el marco de trabajo del PMBOK. Previo al Plan se realiz? un an?lisis PESTEL para analizar el encaje del proyecto en la organizaci?n de Icosaedro, identificando los criterios que se utilizaron para ser seleccionado por la empresa. El proyecto inici? tras la firma del contrato entre la empresa ICOSAEDRO y el Proyecto Especial de Irrigaci?n e Hidroenerg?tico Alto Piura (PEIHAP); identificando los stakeholders, definiendo los objetivos del proyecto, los objetivos del producto y el alcance del proyecto y producto; con los cuales se elabor? la Estructura de Desglose de Trabajo (EDT): procediendo luego a elaborar cada uno de los planes subsidiarios del proyecto: Plan de Gesti?n del Alcance, Plan de Gesti?n del Cronograma, Plan de Gesti?n de Costos, Plan de Gesti?n de Comunicaciones, Plan de Gesti?n de Riesgo, Plan de Gesti?n de Calidad y Plan de Gesti?n de Adquisiciones, etc

Blockage of angiotensin II type I receptor decreases the synthesis of growth factors and induces apoptosis in C6 cultured cells and C6 rat glioma

Angiotensin II (Ang II) is a main effector peptide in the renin–angiotensin system and participates in the regulation of vascular tone. It also has a role in the expression of growth factors that induce neovascularisation which is closely associated to the growth of malignant gliomas. We have shown that the selective blockage of the AT1 receptor of angiotensin inhibites tumour growth, cell proliferation and angiogenesis of C6 rat glioma. The aim of this study was to study the effects of the blockage of AT1 receptor on the synthesis of growth factors, and in the genesis of apoptosis in cultured C6 glioma cells and in rats with C6 glioma. Administration of losartan at doses of 40 or 80 mg kg−1 to rats with C6 glioma significantly decreased tumoral volume and production of platelet-derived growth factor, vascular endothelial growth factor and basic fibroblast growth factor. It also induced apoptosis in a dose-dependent manner. Administration of Ang II increased cell proliferation of cultured C6 cells which decreased by the administration of losartan. Our results suggest that the selective blockage of AT1 diminishes tumoral growth through inhibition of growth factors and promotion of apoptosis

Coastal Marine Planning: Vision of the Maritime Authority. Case of the Department of Bolivar, Colombia

La Planificación Espacial Marina es una herramienta que ha tomado gran importancia a nivel mundial. Alrededor de 70 países han implementado esta iniciativa debido a la creciente actividad en el sector marítimo y a la presión sobre los recursos marinos. Las metodologías aplicadas se ajustan a las características propias de cada país y se pueden articular con otros procesos de ordenamiento. En Colombia aunque se han adelantado procesos en este tema a través de diferentes entidades, no se ha generado un ordenamiento espacial de los usos relacionados con las actividades marítimas. Es por esta razón que la Dirección General Marítima (DIMAR) con su compromiso de convertir a Colombia en una potencia bioceánica, bajo un enfoque holístico y de seguridad integral marítima, realiza su aporte a la gestión de los espacios marino - costeros a través de una metodología de Ordenamiento Marino Costero con una Visión de Autoridad Marítima (OMC: VAM), en la cual se busca analizar las condiciones actuales y futuras empleando Sistemas de Información Geográfica (SIG), análisis multicriterio y un Modelo de Asignación y Co-localización (MAYC). La metodología se aplicó en la zona marino – costera del departamento de Bolívar identificando 55 usos/actividades, obteniendo la zonificación por índice y número de conflictos y el mapa de zonas libres. Con esta información se pretende mejorar el seguimiento, evaluación y actualización de las actividades marítimas en estas áreas, y al ser aplicable en todo el territorio colombiano, facilita la toma de decisiones de las diferentes entidades gubernamentales del país.Marine Spatial Planning is a tool that has acquired significant importance worldwide. Around 70 countries have implemented this initiative given the increased activity within the maritime sector and pressure on marine resources. The methods used are adapted to each country’s characteristics and articulated with other management processes. Although Colombia has progressed through on the processes regarding this issue, through different agencies, marine spatial planning related to maritime activities is absent. Therefore, the General Maritime Directorate (DIMAR in Spanish) through its commitment to turning Colombia into a bi-oceanic power, under a holistic and comprehensive maritime safety approach, contributes to marine and coastal areas management with a methodology for Marine and Coastal Management with a Maritime Authority Vision (MCM: MAV), focused on analyzed current and future conditions using Geographic Information Systems (GIS), multi-criteria analysis, and an Allocation and Co-location Model (ACM). The method was applied to Bolivar Department marine and coastal area, resulting in the identification of 55 uses/activities, and obtaining zoning by index and by the number of conflicts, as well as a map of free areas. This information is intended to improve monitoring, evaluation, and updating of maritime activities in these areas, and because it is applicable throughout the Colombian territory, it facilitates decision-making by several national governmental agencies

Negative Impacts of Human Land Use on Dung Beetle Functional Diversity

The loss of biodiversity caused by human activity is assumed to alter ecosystem functioning. However our understanding of the magnitude of the effect of these changes on functional diversity and their impact on the dynamics of ecological processes is still limited. We analyzed the functional diversity of copro-necrophagous beetles under different conditions of land use in three Mexican biosphere reserves. In Montes Azules pastures, forest fragments and continuous rainforest were analyzed, in Los Tuxtlas rainforest fragments of different sizes were analyzed and in Barranca de Metztitlán two types of xerophile scrub with different degrees of disturbance from grazing were analyzed. We assigned dung beetle species to functional groups based on food relocation, beetle size, daily activity period and food preferences, and as measures of functional diversity we used estimates based on multivariate methods. In Montes Azules functional richness was lower in the pastures than in continuous rainforest and rainforest fragments, but fragments and continuous forest include functionally redundant species. In small rainforest fragments (<5 ha) in Los Tuxtlas, dung beetle functional richness was lower than in large rainforest fragments (>20 ha). Functional evenness and functional dispersion did not vary among habitat types or fragment size in these reserves. In contrast, in Metztitlán, functional richness and functional dispersion were different among the vegetation types, but differences were not related to the degree of disturbance by grazing. More redundant species were found in submontane than in crassicaule scrub. For the first time, a decrease in the functional diversity in communities of copro-necrophagous beetles resulting from changes in land use is documented, the potential implications for ecosystem functioning are discussed and a series of variables that could improve the evaluation of functional diversity for this biological group is proposed