620 research outputs found

    High-spatial-resolution probability maps of drought duration and magnitude across Spain

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    Assessing the probability of occurrence of drought is important for improving current drought assessment, management and mitigation measures, and strategies across Spain. This study employed two well-established drought indices, the Standardized Precipitation Index (SPI) and the Standardized Precipitation Evapotranspiration Index (SPEI), to characterize drought duration and magnitude at different timescales over Spain. In order to map the drought hazard probability, we applied the extreme value theory and tested different thresholds to generate peak-over-threshold (POT) drought duration and magnitude series. Our results demonstrate that the generalized Pareto (GP) distribution performs well in estimating the frequencies of drought magnitude and duration. Specifically, we found a good agreement between the observed and modelled data when using upper percentiles to generate the POT series. Spatially, our estimations suggest a higher probability of extreme drought events in southern and central Spain compared to the northern and eastern regions. Also, our study found spatial differences in drought probability estimations as a function of the selected drought index (i.e. SPI vs. SPEI) and timescale (i.e. 1, 3, 6, and 12 months). Drought hazard probability maps can contribute to the better management of different sectors (e.g. agriculture, water resources management, urban water supply, and tourism) at national, regional, and even local scale in Spain.</p

    The potential of using climate indices as powerful tools to explain mortality anomalies: An application to mainland Spain

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    Changes in the frequency and magnitude of extreme weather events represent one of the key indicators of climate change and variability. These events can have an important impact on mortality rates, especially in the ageing population. This study assessed the spatial and seasonal distributions of mortality rates in mainland Spain and their association with climatic conditions over the period 1979–2016. The analysis was done on a seasonal and annual basis using 79 climatic indices and regional natural deaths data. Results indicate large spatial variability of natural deaths, which is mostly related to how the share of the elderly in the population varied across the studied regions. Spatially, both the highest mortality rates and the largest percentage of elders were found in the northwest areas of the study domain, where an extreme climate prevails, with very cold winters and hot summers. A strong seasonality effect was observed, winter shows more than 10% of natural deaths compared to the rest of the seasons. Also, results suggest a strong relation between climatic indices and natural deaths, albeit with a high spatial and seasonal variability. Climatic indices and natural deaths show a stronger correlation in winter and summer than in spring and autumn. © 2021 The Author

    INFLUENCE OF FOLIAR APPLICATION OF GIBBERELLIC ACID AND LIQUORICE ROOT EXTRACT ON GROWTH, VOLATILE OIL YIELD PRODUCTIVITY AND ANTIMICROBIAL ACTIVITY IN GERANIUM (PELARGONIUM GRAVEOLENS L. HER.) PLANTS

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    This work was carried out during the two successive seasons (2019/2020 and 2020/2021) in the Experimental Farm of Horticulture Research Station at Sids, Beni-Suef Governorate, to investigate the effect of foliar application of gibberellic acid (GA3) at 100, 200 and 300 ppm and spraying of two extractions of liquorice root (aqueous LRE at 5 and 10 g/l and ethanolic LRE at 5 and 10 g/l) and their interaction on the vegetative growth (plant height, number of branches, herb fresh weight per plant and per feddan), volatile oil productivity (oil %, yield per plant and per feddan), total chlorophyll and total carbohydrates,NPK percentages, as well as antimicrobial activity of geranium plants.Obtained results revealed that the best vegetative growth characteristics, volatile oil productivity, total chlorophyll and carbohydrates were obtained due to the use of the high dose (300 ppm) and medium dose (200 ppm) of gibberellic acid with no significant differences between them. Concerning liquorice root extract treatments, all of the prementioned growth parameters, oil yield and chemical traits were considerably augmented due to the high dose of aqueous LRE at 10 g/l treatment followed by ethanolic LRE at 10 g/l, while LRE aqu. at 5 g/l gave the least values. In regard to the interaction between the two studied factors, the highest growth, yield and chemical composition values were given by GA3 at 200 or 300 ppm in combination with LRE aqu. at 10 g/l. Overall, the most powerful antimicrobial activity was recorded of the combination treatment in the two geranium cuts. Therefore, it could be advised from the economical and environmental point of view, to supply geranium plants with GA3 at 200 ppm and LRE aqu. at 10 g/l to improve the volatile oil yield and the antimicrobial activit

    ESTROGENS IMPROVE THE CARDIOVASCULAR ALTERATIONS IN FRUCTOSE-INDUCED INSULIN RESISTANT OVARIECTOMIZED RATS

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    Objective: The present study aimed to investigate the possible improving effects of 17-β estradiol (EST) and genistein (GEN) on the cardiovascular changes associated with fructose (21% in drinking water for 8 weeks)-induced insulin resistance.Methods: Sham-operated and ovariectomized mature female rats were included in this study. Insulin-resistant ovariectomized animals were sc treated with EST (100 µg/kg) or GEN (1 mg/kg) on the daily basis for 21 consecutive days.Results: Induction of insulin resistance in both sham-operated and ovariectomized rats decreased the vascular responsiveness of isolated aortic rings towards the vasoconstrictor norepinephrine and the vasodilator acetylcholine (Ach) with no changes towards the vasodilator sodium nitroprusside. Fructose-induced insulin resistance was also associated with an elevation in the blood pressure (BP) with decreased serum level of nitric oxide (NO). Treatment of insulin-resistant ovariectomized rats with either EST or GEN improved the vascular responsiveness of isolated aortic rings towards Ach and succeeded to reduce the elevated BP. Moreover, both EST and GEN decreased the insulin resistance/compensatory hyper insulinaemia. Treatment with EST increased serum NO level.Conclusion: EST and GEN have the ability to improve the endothelium-dependent relaxation in insulin-resistant ovariectomized rats and modulate the elevated BP.Â

    Twelve years of daily weather descriptions in North America in the eighteenth century (Mexico City, 1775-86)

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    © 2019 American Meteorological Society. The authors are very grateful to Ana Gavilán and César Paradinas for their help with the transcription of the FZO weather diary. Carlos Ordóñez reviewed the language. This work was supported by the research projects IMDROFLOOD financed by the Water Works 2014 cofunded call of the European Commission and INDECIS, which is part of ERA4CS, an ERA-NET initiated by JPI Climate by the European Union (Grant 690462). Marina Peña-Gallardo was granted by the Spanish Ministry of Economy and Competitiveness (MINECO), and Ahmed El Kenawy was supported by a postdoctoral Juan de la Cierva contract by the Spanish Ministry of Economy and Competitiveness (MINECO). F. Domínguez-Castro, M. C. Gallego, J. M. Vaquero, R. García Herrera, M. Peña-Gallardo, A. El Kenawy, and S. M. Vicente-SerranoDepto. de Física de la Tierra y AstrofísicaFac. de Ciencias FísicasTRUEUnión Europea. H2020Ministerio de Economía y Competitividad (MINECO)JPI Climate by the European Unionpu

    Recent changes and drivers of the atmospheric evaporative demand in the Canary Islands

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    We analysed recent evolution and meteorological drivers of the atmospheric evaporative demand (AED) in the Canary Islands for the period 1961-2013. We employed long and high-quality time series of meteorological variables to analyse current AED changes in this region and found that AED has increased during the investigated period. Overall, the annual ETo, which was estimated by means of the FAO-56 Penman-Monteith equation, increased significantly by 18.2 mm decade-1 on average, with a stronger trend in summer (6.7 mm decade-1). In this study we analysed the contribution of (i) the aerodynamic (related to the water vapour that a parcel of air can store) and (ii) radiative (related to the available energy to evaporate a quantity of water) components to the decadal variability and trends of ETo. More than 90 % of the observed ETo variability at the seasonal and annual scales can be associated with the variability in the aerodynamic component. The variable that recorded more significant changes in the Canary Islands was relative humidity, and among the different meteorological factors used to calculate ETo, relative humidity was the main driver of the observed ETo trends. The observed trend could have negative consequences in a number of water-depending sectors if it continues in the future

    Assessment of vapor pressure deficit variability and trends in Spain and possible connections with soil moisture

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    The Vapor Pressure Deficit (VPD) is one of the most relevant surface meteorological variables; with important implications in ecology, hydrology, and atmosphere. By understanding the processes involved in the variability and trend of the VPD, it is possible to assess the possible impacts and implications related to both physical and human environments, like plant function, water use efficiency, net ecosystem production, atmospheric CO2 growth rate, etc. This study analysed recent temporal variability and trends in VPD in Spain between 1980 and 2020 using a recently developed high-quality dataset. Also, the connection between VPD and soil moisture and other key climate variables (e.g. air temperature, precipitation, and relative humidity) was assessed on different time scales varying from weekly to annual. The objective was to determine if changes in land-atmosphere feedbacks connected with soil moisture and evapotranspiration anomalies have been relevant to assess the interannual variability and trends in VPD. Results demonstrate that VPD exhibited a clear seasonality and dominant positive trends on both the seasonal (mainly spring and summer) and annual scales. Rather, trends were statistically non-significant (p > 0.05) during winter and autumn. Spatially, VPD positive trends were more pronounced in southern and eastern of Spain. Also, results suggest that recent trends of VPD shows low contribution of variables that drive land-atmosphere feedbacks (e.g. evapotranspiration, and soil moisture) in comparison to the role of global warming processes. Notably, the variability of VPD seems to be less coupled with soil moisture variability during summertime, while it is better interrelated during winter, indicating that VPD variability would be mostly related to climate variability mechanisms that control temperature and relative humidity than to land-atmosohere feedbacks. Overall, our findings highlight the importance of assessing driving forces and physical mechanisms that control VPD variability using high-quality climate datasets, especially, in semiarid and sub-humid regions of the world

    Geophysical site assessment of an active urban development site, South Eastern Suburb of Cairo, Egypt

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    There has been significant structural damage of newly-built residential buildings in Quarter-27 District in the South of Cairo, Egypt. The proximity of an active limestone quarry may also be affecting ground stability. This paper shows how a near-surface geophysics survey could characterize the site, unusually after the initial housing construction had already been undertaken. Geophysical surveys included seismic refraction (acquired between phases of quarry blasting), electrical resistivity and ground penetrating radar 1D and 2D datasets. Geophysical results produced maps of a 3D ground model that also included water table depth, known major faults and a saturated layer that may have caused the building damage. ERT and GPR data was deemed optimal of the geophysical techniques trialled. This study shows that it is possible to undertake geophysical surveys to characterize a restricted urban site development
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