3,086 research outputs found

    Predictive modeling, geographic distribution and conservation status of Tomopeas ravus Miller, 1900 (Chiroptera, Molossidae)

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    Tomopeas ravus, el murciélago de orejas romas, se conoce solo de 13 localidades confirmadas en Perú y actualmente se encuentra listada como En Peligro (B2 ab (iii)) por la UICN. La distribución, extensión de ocurrencia y el área de vida de esta especie no han sido esclarecidos completamente. Presentamos el primer modelo predictivo basado en los registros conocidos y el primer acercamiento geográfico para la especie. Basados en los 13 registros confirmados se construyó un modelo de hábitat de máxima entropía determinando previamente las variables ambientales de mayor importancia para el modelo. Se estimó un índice predictivo aceptable (0.970) para el modelo final. Se determinó las zonas de mayor probabilidad de ocurrencia para esta especie y se estimó el área de distribución mediante el método del polígono mínimo convexo (PMC). El área prioritaria más importante identificada para la conservación de esta especie se sitúa al norte de Perú, entre los Departamentos de Tumbes y Piura. Se recomienda utilizar el presente modelo como herramienta útil para futuras evaluaciones de la conservación de esta especie.Tomopeas ravus, known as blunt - eared bat, is known only from thirteen confirmed localities in Peru and is currently listed as Endangered (B2 ab (iii)) by the IUCN. The distribution, occurrence extension and home range of this species is not have been completely clarified. We presents the first predictive model based on the known records and the first geographic approach to this species. On the basis of thirteen confirmed records we built a habitat model of maximum entropy determining previously the most important environmental variables for the model. An acceptable predictive index (0.970) was obtained for the final model. We determined the areas of major probability of occurrence for this species and felt the geographic distribution through the method of the polygon mínimum convex (PMC). The priority area identified for the conservation of this species is located in the northern of Peru, between the Departments of Tumbes and Piura. We recommended to use the present model as a useful tool for future evaluations of conservation of this species

    Advantages and disadvantages on photosynthesis measurement techniques: A review

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    Through photosynthesis, green plants and cyanobacteria are able to transfer sunlight energy to molecular reaction centers for conversion into chemical energy with nearly 100% efficiency. Speed is the key as the transfer of the solar energy takes place almost instantaneously such that little energy is wasted as heat. How photosynthesis achieves this near instantaneous energy transfer is a longstanding mystery that may have finally been solved. Measurements of this process are useful in order to understand how it might be controlled and how the phytomonitoring of plant development to increase productivity can be carried out. Techniques in this sense have evolved and nowadays several have been used for this purpose. Thus, the aim of this paper is to present a review of the various methods and principles that have been used in measuring photosynthesis presenting the advantages and disadvantages of various existing measurement methodologies in order to recommend the most appropriate method according to the needs of specific investigations

    Potential of mathematical modeling in fruit quality

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    A review of mathematical modeling applied to fruit quality showed that these models ranged inresolution from simple yield equations to complex  representations of processes as respiration, photosynthesis and assimilation of nutrients. The latter models take into account complex  genotype environment interactions to estimate their effects on growth and yield. Recently, models are used to estimate seasonal changes in quality traits as fruit size, dry matter, water content and the concentration of sugars and acids, which are very important for flavor and aroma. These models have demonstrated their ability to generate relationships between physiological variables and quality attributes (allometric relations). This new kind of hybrid models has sufficient complexity to predict quality traits behavior

    A multiple-trait analysis of ecohydrological acclimatisation in a dryland phreatophytic shrub

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    Water is the main limiting factor for groundwater-dependent ecosystems (GDEs) in drylands. Predicted climate change (precipitation reductions and temperature increases) and anthropogenic activities such as groundwater drawdown jeopardise the functioning of these ecosystems, presenting new challenges for their management. We developed a trait-based analysis to examine the spatiotemporal variability in the ecophysiology of Ziziphus lotus, a long-lived phreatophyte that dominates one of the few terrestrial GDEs of semiarid regions in Europe. We assessed morpho-functional traits and stem water potential along a naturally occurring gradient of depth-to-groundwater (DTGW, 2–25 m) in a coastal aquifer, and throughout the species-growing season. Increasing DTGW and salinity negatively affected photosynthetic and transpiration rates, increasing plant water stress (lower predawn and midday water potential), and positively affected Huber value (sapwood cross-sectional area per leaf area), reducing leaf area and likely, plant hydraulic demand. However, the species showed greater salt-tolerance at shallow depths. Despite groundwater characteristics, higher atmospheric evaporative demand in the study area, which occurred in summer, fostered higher transpiration rates and water stress, and promoted carbon assimilation and water loss more intensively at shallow water tables. This multiple-trait analysis allowed us to identify plant ecophysiological thresholds related to the increase in salinity, but mostly in DTGW (13 m), and in the evaporative demand during the growing season. These findings highlight the existence of tipping points in the functioning of a long-lived phreatophyte in drylands and can contribute to the sustainable management of GDEs in southern Europe, paving the way for further studies on phreatophytic species

    International Courts and the Crime of Genocide

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    En este trabajo realizo un análisis jurídico de los elementos constitutivos (tanto subjetivos como objetivos) del crimen de genocidio, tal y como han sido interpretados y aplicados por la jurisprudencia internacional. En concreto, se estudia la jurisprudencia de la Corte Internacional de Justicia, del Tribunal Internacional Penal para la antigua Yugoslavia y del Tribunal Internacional Penal para Ruanda sobre el crimen de genocidio

    Ultra-compact planoconcave zoned metallic lens based on the fishnet metamaterial

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    The following article appeared Pacheco-Pena, V., Orazbayev, B., Torres, V., Beruete, M., & Navarro-Cia, M. (n.d). Ultra-compact planoconcave zoned metallic lens based on the fishnet metamaterial. Applied Physics Letters, 103(18), and may be found at http://dx.doi.org/10.1063/1.4827876.A 1.5λ0 -thick planoconcave zoned lens based on the fishnet metamaterial is demonstrated experimentally at millimeter wavelengths. The zoning technique applied allows a volume reduction of 60% compared to a full fishnet metamaterial lens without any deterioration in performance. The structure is designed to exhibit an effective refractive index n = -0.25 at f = 56.7GHz (λ0 = 5.29 mm) with a focal length FL = 47.62 mm = 9λ0. The experimental enhancement achieved is 11.1dB, which is in good agreement with simulation and also with previous full fishnet metamaterial lenses and opens the door for integrated solutions.This work was supported in part by the Spanish Government under contract Consolider Engineering Metamaterials CSD2008-00066 and contract TEC2011- 28664-C02-01. V.P.-P. was sponsored by Spanish Ministerio de Educacion, Cultura y Deporte under Grant No. FPU AP- 2012-3796. B.O. was sponsored by Spanish Ministerio de Economıa y Competitividad under Grant No. FPI BES-2012- 054909. V.T. is sponsored by the Universidad Publica de Navarra. M.B. is sponsored by the Spanish Government via RYC-2011-08221. M.N.-C. was supported by the Imperial College Junior Research Fellowship

    The relevance of Brownian relaxation as power absorption mechanism in Magnetic Hyperthermia

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    The Linear Response Theory (LRT) is a widely accepted framework to analyze the power absorption of magnetic nanoparticles for magnetic fluid hyperthermia. Its validity is restricted to low applied fields and/or to highly anisotropic magnetic nanoparticles. Here, we present a systematic experimental analysis and numerical calculations of the specific power absorption for highly anisotropic cobalt ferrite (CoFe 2 O 4 ) magnetic nanoparticles with different average sizes and in different viscous media. The predominance of Brownian relaxation as the origin of the magnetic losses in these particles is established, and the changes of the Specific Power Absorption (SPA) with the viscosity of the carrier liquid are consistent with the LRT approximation. The impact of viscosity on SPA is relevant for the design of MNPs to heat the intracellular medium during in vitro and in vivo experiments. The combined numerical and experimental analyses presented here shed light on the underlying mechanisms that make highly anisotropic MNPs unsuitable for magnetic hyperthermia
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