252 research outputs found

    Spatial characterization of glacial and periglacial landforms in the highlands of Sierra Nevada (Spain)

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    Sierra Nevada constitutes the southernmost and highest massif in the Iberian Peninsula, with elevations exceeding 3000m. Two large glacial advances were recorded during the Last Glaciation and several minor advances occurred until the Early Holocene. Since then, periglacial activity has prevailed above 2500m. Here, we present a new and more accurate geomorphological map of the highlands of Sierra Nevada, integrating in a GIS environment i) high resolution satellite imagery, ii) topographic data, and iii) field observations. This approach has allowed a better characterization of the spatial extent of cold-climate morphogenic processes and associated landforms formed during the Last Glaciation and subsequent deglaciation. Despite its extension and high altitude, the steep relief of Sierra Nevada and its southern location conditioned a significantly lower glaciated surface (104.6km2) with respect to other Iberian massifs. We have also inferred the paleoclimatic conditions of the study area through the calculation of Equilibrium Line Altitudes (ELAs). The distribution of the lowest moraines suggests an ELA for the maximum glacial extent at 2525m in the northern slope and 2650m in the southern side, increasing towards the east. Local ELA differences are related to: (i) the influence of the warmer Mediterranean Sea in contrast to the cooler Atlantic Ocean, (ii) the climate with more continental characteristics on the northern slope, and (iii) the microscale control of the local topography. Mean annual air temperatures in the ice-free summit plateaus were between -4/-6°C during the maximum local glacial extent, determining permafrost conditions with intense periglacial dynamics. Rock glaciers and protalus lobes developed until 2500m, the lowest boundary for permafrost regime. The distribution of other glacial and periglacial landforms within the limits of the maximum ice extent provides evidence to better understand the extent of subsequent glacial stages and post-glacial landscape evolution in Sierra Nevada.info:eu-repo/semantics/publishedVersio

    Effect of titanium foliar applications on tomato fruits from plants grown under salt stress conditions

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    Salt stress affects plant metabolism, while beneficial elements such as titanium (Ti) may stimulate adaptive responses to mitigate salt stress. Here we evaluated the main effects of sodium chloride (NaCl 0, 50 and 100 mM) in the nutrient solution, and of titanium foliar spray (Ti 0.75 and 150 mg L-1), as well as the interaction of these study factors, on tomato cv. ‘Rio Supremo’ performance in greenhouse. Plants were treated with NaCl during 80 d through automated drip irrigation; while eight Ti foliar sprayings were applied with a manual sprayer, at intervals of 10 d each. Yield and quality parameters of fruits were evaluated in the second cluster. NaCl reduced yield parameters, pH value and increased the titratable acidity (TA), electrical conductivity (EC), and total soluble solids (TSS), as well as the TSS/TA ration in the fruits. Ti did not affect yield parameters, though it reduced the pH and increased the TSS/TA ratio of fruits. NaCl and Ti have differential effects on fruit quality as separate factors, while the interaction of both factors revealed that Ti effects dependent on the presence of NaCl and its level in the nutrient solution. In conclusion, Ti did not mitigate the negative effects of saline stress on the evaluated yield parameters, but importantly, with moderate levels of NaCl in the nutrient solution (50 mM), Ti increased EC, TA and TSS of fruits

    Degradation of buried ice and permafrost in the Veleta cirque (Sierra Nevada, Spain) from 2006 to 2013 as a response to recent climate trends

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    The Veleta cirque is located at the foot of the Veleta peak, one of the highest summits of the Sierra Nevada National Park (southern Spain). This cirque was the source of a glacier valley during the Quaternary cold periods. During the Little Ice Age it sheltered a small glacier, the most southerly in Europe, about which we have possessed written records since the 17th century. This glacier still had ice residues until the mid-20th century. This ice is no longer visible, but a residue persists along with discontinuous permafrost trapped under strata of rock blocks that make up an incipient rock glacier. From 2006 to 2013, this rock glacier was monitored by measurement of the temperature of the active layer, the degree of snow cover on the ground, movements of the body of the rock glacier and geophysical prospection inside it. The results show that the relict ice and trapped permafrost have been steadily declining. The processes that explain this degradation occur in chain, starting from the external radiation that affects the ground in summer, which is when the temperatures are higher. In effect, when this radiation steadily melts the snow on the ground, the thermal expansive wave advances into the heart of the active layer, reaching the ceiling of the frozen mass, which it then degrades and melts. In this entire linked process, the circulation of meltwaters fulfils a highly significant function, as they act as heat transmitters. The complementary nature of these processes explains the subsidence and continuous changes in the entire clastic pack and the melting of the frozen ceiling on which it rests. This happens in summer in just a few weeks. All these events, in particular the geomorphological ones, take place on the Sierra Nevada peaks within certain climate conditions that are at present unfavourable to the maintenance of snow on the ground in summer. These conditions could be related to recent variations in the climate, starting in the mid-19th century and most markedly since the second half of the 20th century. The work and results highlight the climate sensitivity of the peaks of the Sierra Nevada to the effect of climate change and its impact on the dynamics of ecosystems, which is a benchmark for evaluating the current evolution of landscapes of Mediterranean high mountains.We are grateful to the research projects 018/2007 of the Autonomous Organisation of National Parks and CSO2012-30681 from the Ministry of Economy and Competition

    Psychophysiological condition in the performance of sanitary-military tasks with surgical mask

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    Using a quasi-experimental design with 19 health workers (33.7 ± 5.1 years), the importance of physical and cognitive condition and performance when wearing protective equipment with a surgical mask during training situations in significant contexts of military intervention has been analysed. Heart rate and its variability, glucose levels, thermoregulation, explosive strength and perceived effort in specific motor performance tasks (tapping test, tourniquet, ammunition), and cognitive and decisional performance (triage) were measured. The results indicate significant differences (p < 05) depending on the physical condition (blood glucose and explosive strength), gender (explosive strength and tourniquet), smoking habit (perceived effort) and specialty (glucose level) in the study group. In conclusion, the importance of physical and psychological training is highlighted to improve the operational response in health-military situations that require the use of a surgical maskSe ha analizado, mediante un diseño cuasi-experimental con 19 sanitarios (33.7 ± 5.1 años), la importancia de la condición física, cognitiva y el rendimiento al portar un equipo de protección con mascarilla quirúrgica durante situaciones de entrenamiento en contextos significativos de intervención militar. Se midieron la frecuencia cardíaca y su variabilidad, los niveles de glucosa, la termorregulación, la fuerza explosiva y el esfuerzo percibido en tareas de rendimiento motor específicas (tapping test, torniquete, municionamiento), y de rendimiento cognitivo y decisional (triaje). Los resultados indican diferencias significativas (p < 05) en función de la condición física (glucemia y fuerza explosiva), del género (fuerza explosiva y torniquete), del hábito tabáquico (esfuerzo percibido) y del cuerpo de pertenencia (nivel de glucemia) en el grupo de estudio. Como conclusión, se destaca la importancia del entrenamiento físico y psicológico para la mejora de la respuesta operativa en situaciones sanitario-militares que requieren el uso de mascarilla quirúrgic

    A local real-time bar detector based on the multiscale Radon transform

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    We propose a local bar-shaped structure detector that works in real time on high-resolution images. It is based on the Radon transform. Specifically in the muti-scale variant, which is especially fast because it works in integer mathematics and does not use interpolation. The Radon transform conventionally works on the whole image, and not locally. In this paper we describe how by stopping at the early stages of the Radon transform we are able to locate structures locally. We also provide an evaluation of the performance of the algorithm running on the CPU, GPU and DSP of mobile devices to process at acquisition time the images coming from the device’s camera

    Effect of antioxidants and pH on browning and firmness of minimally processed eggplant

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    Minimal processing of eggplants (Solanum melongena L.) generates a rapid onset of enzymatic browning, tissue softening and water loss that limits their shelf life. The aim of this study was to evaluate the effect of 1% ascorbic acid and 2% calcium ascorbate in aqueous solution at natural pH of the antioxidant (pH 2.6 and 7.8, respectively), or adjusted to pH 5 with generally recognized as safe substances, to maintain the quality of minimally processed eggplant stored at 5 °C for 6 d. Water was used as a control. The colour, firmness, polyphenol oxidase activity, and visual quality was evaluated in the freshly cut fruit at 3 and 6 d of storage. No effect of the treatments on firmness or polyphenol oxidase activity was observed. At 3 d of storage, a correlation was observed between polyphenol oxidase activity and the visual evaluation of the cut product. Samples treated with 2% calcium ascorbate and the rest of the treatments at pH 5 had a lower browning index than those treated with 1% ascorbic acid and the control. At the end of the storage period, the visual quality of the eggplant samples treated with 1% ascorbic acid at pH 5 was evaluated above the marketing limit, whereas those treated with 1% ascorbic acid at pH 2.6 had the lowest quality indicators. An adjustment to pH 5 helps to preserve the luminosity and visual quality of the eggplant, however firmness was not affected by calcium ascorbate or the pH of the medium

    Nuclear translocation of glutaminase GLS2 in human cancer cells associates with proliferation arrest and differentiation

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    Glutaminase (GA) catalyzes the first step in mitochondrial glutaminolysis playing a key role in cancer metabolic reprogramming. Humans express two types of GA isoforms: GLS and GLS2. GLS isozymes have been consistently related to cell proliferation, but the role of GLS2 in cancer remains poorly understood. GLS2 is repressed in many tumor cells and a better understanding of its function in tumorigenesis may further the development of new therapeutic approaches. We analyzed GLS2 expression in HCC, GBM and neuroblastoma cells, as well as in monkey COS-7 cells. We studied GLS2 expression after induction of differentiation with phorbol ester (PMA) and transduction with the full-length cDNA of GLS2. In parallel, we investigated cell cycle progression and levels of p53, p21 and c-Myc proteins. Using the baculovirus system, human GLS2 protein was overexpressed, purified and analyzed for posttranslational modifications employing a proteomics LC-MS/MS platform. We have demonstrated a dual targeting of GLS2 in human cancer cells. Immunocytochemistry and subcellular fractionation gave consistent results demonstrating nuclear and mitochondrial locations, with the latter being predominant. Nuclear targeting was confirmed in cancer cells overexpressing c-Myc- and GFP-tagged GLS2 proteins. We assessed the subnuclear location finding a widespread distribution of GLS2 in the nucleoplasm without clear overlapping with specific nuclear substructures. GLS2 expression and nuclear accrual notably increased by treatment of SH-SY5Y cells with PMA and it correlated with cell cycle arrest at G2/M, upregulation of tumor suppressor p53 and p21 protein. A similar response was obtained by overexpression of GLS2 in T98G glioma cells, including downregulation of oncogene c-Myc. Furthermore, human GLS2 was identified as being hypusinated by MS analysis, a posttranslational modification which may be relevant for its nuclear targeting and/or function. Our studies provide evidence for a tumor suppressor role of GLS2 in certain types of cancer. The data imply that GLS2 can be regarded as a highly mobile and multilocalizing protein translocated to both mitochondria and nuclei. Upregulation of GLS2 in cancer cells induced an antiproliferative response with cell cycle arrest at the G2/M phase

    Análisis distribucional de la abeja sin aguijón Scaptotrigona mexicana (Apidae: Meliponini) en México: Información de referencia para Veracruz

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    Objective: To obtain the specific geographic distribution based on the stingless bee Scaptotrigonna mexicana in Mexico and the state of Veracruz. Design/methodology/approach: 2202 coordinates of the Gbif database were filtered using a spocc database manager in the programming language R. Subsequently, 55 coordinates were obtained with which multiple models of maximum entropy were calibrated with nine predictive environmental variables of 19 initials in MaxEnt 3.3 .3 in ENMeval. The best performing model (AUC&gt; 0.897 and AICc = 0) was reclassified into 5 categories of climatic suitability with the k-means clustering technique. Results: The specific geographic distribution pattern was obtained based on the climatic suitability of S. mexicana in Mexico and Veracruz, which was classified into five categories: very low or zero, low, medium, high and very high. Here we show two large zones of climatic suitability in Mexico for S. mexicana, which could be divided by the geographical barrier of the Isthmus of Tehuantepec, the first zone is located in the Sierra Norte de Puebla and Veracruz influenced by the Transversal Mountain System and the Sierra Madre Oriental and the second in the south of the country in the South Pacific Coast, Chiapas and Guatemala. The variables that determine this pattern is the seasonality of temperature and precipitation in the wettest and driest quarter. In Veracruz, 52 municipalities were divided into two large groups with potential for the exploitation and conservation of S. mexicana, the first in the North zone and the second in the Central Zone of the state. Findings/conclusions: The incorporation of environmental variables of greater spatial and temporal resolution is necessary to extend the accuracy of the pollination pattern of S. mexicana at local scales.Objetivo: Obtener la distribución geográfica específica con base en la abeja sin aguijón Scaptotrigona mexicana en México y el estado de Veracruz. Diseño/metodología/aproximación: Se filtraron 2202 coordenadas de la base de datos Gbif utilizando un gestor de base datos spocc en el lenguaje de programación R. Posteriormente se obtuvieron 55 coordenadas con las que se calibraron múltiples&nbsp; modelos de máxima entropía con nueve variables ambientales predictivas de 19 iniciales en MaxEnt 3.3.3 en ENMeval. El modelo con mejor rendimiento (AUC&gt; 0.897 y AICc = 0) se reclasificó en cinco categorías de idoneidad climática con la técnica de clustering k-means. Resultados: Se obtuvo el patrón de distribución geográfico específico basado en la idoneidad climática de S. mexicana en México y Veracruz, el cual se clasificó en 5 categorías: muy baja o nula, baja, media, alta y muy alta. Aquí mostramos dos grandes zonas de idoneidad climática en México para S. mexicana, las cuales podrían estar divididas por la barrera geográfica del Istmo de Tehuantepec, la primera zona se localiza en la Sierra Norte de Puebla y Veracruz influenciada por el Sistema Montañoso Transversal y la Sierra Madre Oriental y la segunda al sur de país en la Costa del Pacifico Sur, Chiapas y Guatemala. En Veracruz se encontraron 50 municipios divididos en dos grandes grupos con potencial para el aprovechamiento y conservación de S. mexicana, el primero en la zona Norte y el segundo en la Zona Centro del estado. Limitaciones del estudio/implicaciones: Es necesario la incorporación de variables ambientales de mayor resolución espacial y temporal, para ampliar la precisión del patrón de polinización de S. mexicana a escalas locales. Hallazgos/conclusiones: Existen dos grandes zonas de distribución de S. mexicana en en el país, localizadas en zona norte y la zona sur delimitados claramente por el Istmo de Tehuantepec. En Veracruz hay un total de 50 municipios distribuidos en la zona norte y centro que se benefician de forma potencial por el patrón de distribución S. mexicana, con medio, alto y muy alto para el aprovechamiento de la misma

    Net Efficacy Adjusted for Risk (NEAR): A Simple Procedure for Measuring Risk:Benefit Balance

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    BACKGROUND: Although several mathematical models have been proposed to assess the risk:benefit of drugs in one measure, their use in practice has been rather limited. Our objective was to design a simple, easily applicable model. In this respect, measuring the proportion of patients who respond favorably to treatment without being affected by adverse drug reactions (ADR) could be a suitable endpoint. However, remarkably few published clinical trials report the data required to calculate this proportion. As an approach to the problem, we calculated the expected proportion of this type of patients. METHODOLOGY/PRINCIPAL FINDINGS: Theoretically, responders without ADR may be obtained by multiplying the total number of responders by the total number of subjects that did not suffer ADR, and dividing the product by the total number of subjects studied. When two drugs are studied, the same calculation may be repeated for the second drug. Then, by constructing a 2 x 2 table with the expected frequencies of responders with and without ADR, and non-responders with and without ADR, the odds ratio and relative risk with their confidence intervals may be easily calculated and graphically represented on a logarithmic scale. Such measures represent "net efficacy adjusted for risk" (NEAR). We assayed the model with results extracted from several published clinical trials or meta-analyses. On comparing our results with those originally reported by the authors, marked differences were found in some cases, with ADR arising as a relevant factor to balance the clinical benefit obtained. The particular features of the adverse reaction that must be weighed against benefit is discussed in the paper. CONCLUSION: NEAR representing overall risk-benefit may contribute to improving knowledge of drug clinical usefulness. As most published clinical trials tend to overestimate benefits and underestimate toxicity, our measure represents an effort to change this trend
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