Growth and photosynthetic responses to copper stress of an invasive cordgrass, Spartina densiflora     

Mateos-Naranjo E  Redondo-Gómez S  Cambrollé J  Enrique Figueroa M 《Marine environmental research》2008,66(4):459-465

Spartina densiflora Brongn. is found in coastal marshes of south-west Spain, growing in sediments with between 300 and 3000mg Cu kg(-1) total soil DW (450-4500mg Cu kg(-1) supposing that the soil porosity is 0.5). An experiment was designed to investigate the effect of copper from 0 to 5000mgkg(-1) (64mmoll(-1)) on the photosynthetic apparatus and the growth of S. densiflora. We also determined total ash, copper, calcium, magnesium and phosphorous concentrations, as well as C/N ratio. S. densiflora survived to concentrations as high as 320mg Cukg(-1) DW in leaves, although excess of Cu diminished water use efficiency and Ca-, Mg- and P-uptake. Also, quantum efficiency of PSII, net photosynthetic rate, stomatal conductance and pigment concentrations declined with increasing external Cu. Finally, the decline in the photosynthetic function resulted in a biomass reduction of between 50 and 80% (for 600 and 5000mg Cu kg(-1), respectively).  相似文献   

Season‐based rainfall–runoff modelling using the probability‐distributed model (PDM) for large basins in southeastern Brazil          下载免费PDF全文

Rong Zhang  Luz Adriana Cuartas  Luiz Valerio de Castro Carvalho  Karinne Reis Deusdará Leal  Eduardo Mário Mendiondo  Narumi Abe  Stephen Birkinshaw  Guilherme Samprogna Mohor  Marcelo Enrique Seluchi  Carlos Afonso Nobre 《水文研究》2018,32(14):2217-2230

Southeastern Brazil is characterized by seasonal rainfall variability. This can have a great social, economic, and environmental impact due to both excessive and deficient water availability. During 2014 and 2015, the region experienced one of the most severe droughts since 1960. The resulting water crisis has seriously affected water supply to the metropolitan region of São Paulo and hydroelectric power generation throughout the entire country. This research considered the upstream basins of the southeastern Brazilian reservoirs Cantareira (2,279 km²; water supply) and Emborcação (29,076 km²), Três Marias (51,576 km²), Furnas (52,197 km²), and Mascarenhas (71,649 km²; hydropower) for hydrological modelling. It made the first attempt at configuring a season‐based probability‐distributed model (PDM‐CEMADEN) for simulating different hydrological processes during wet and dry seasons. The model successfully reproduced the intra‐annual and interannual variability of the upstream inflows during 1985–2015. The performance of the model was very satisfactory not only during the wet, dry, and transitional seasons separately but also during the whole period. The best performance was obtained for the upstream basin of Furnas, as it had the highest quality daily precipitation and potential evapotranspiration data. The Nash–Sutcliffe efficiency and logarithmic Nash–Sutcliffe efficiency were 0.92 and 0.93 for the calibration period 1984–2001, 0.87 and 0.88 for the validation period 2001–2010, and 0.93 and 0.90 for the validation period 2010–2015, respectively. Results indicated that during the wet season, the upstream basins have a larger capacity and variation of soil water storage, a larger soil water conductivity, and quicker surface water flow than during the dry season. The added complexity of configuring a season‐based PDM‐CEMADEN relative to the traditional model is well justified by its capacity to better reproduce initial conditions for hydrological forecasting and prediction. The PDM‐CEMADEN is a simple, efficient, and easy‐to‐use model, and it will facilitate early decision making and implement adaptation measures relating to disaster prevention for reservoirs with large‐sized upstream basins.  相似文献   

Control of the seismic response of a composite tall building modelled by two interconnected shear beams     

J. Enrique Luco  Francisco C. P. De Barros 《地震工程与结构动力学》1998,27(3):205-223

The possibility of controlling the seismic response of tall buildings by use of a structural system consisting of a stiff and lightly damped external structure and a very flexible and moderately damped internal structure connected by stiff links at a few elevations is explored. Optimal damping values for the internal structure are obtained by consideration of the response on the composite structure in the vicinity of its fundamental mode. The resulting optimal damping values depend on the relative stiffness of both structures. Numerical results in the frequency and time domain are used to illustrate the advantages of such a system for seismic excitation. The possibility of using flexible links between the internal and external structures to moderate the required reduction of stiffness in the internal structure is also explored. © 1998 John Wiley & Sons, Ltd.  相似文献   

Earthquake-induced damage detection and localization in masonry structures using smart bricks and Kriging strain reconstruction: A numerical study     

Enrique García-Macías  Filippo Ubertini 《地震工程与结构动力学》2019,48(5):548-569

The intrinsic vulnerability of masonry structures to seismic events makes structural health monitoring of the utmost importance for the conservation of the built heritage. The development of piezoresistive bricks, also termed smart bricks, is an innovative technology recently proposed by the authors for the monitoring of such structures. Smart bricks exhibit measurable variations in their electrical properties when subjected to external loads or, alternatively, strain self-sensing capabilities. Therefore, the deployment of a network of smart bricks into a masonry structure confers self-diagnostic properties to the host structure. In this light, this paper presents a theoretical investigation on the application of smart bricks to full-scale masonry structures for seismic assessment. This includes the study of the convenience of providing electrical isolation conditions to the sensors, as well as the effectiveness of smart bricks when installed into either new constructions or in pre-existing structures. Secondly, numerical results are presented on the seismic analysis of a three-dimensional masonry building equipped with a network of smart bricks. Finally, in order to map the strain field throughout the structure exploiting the outputs of a limited number of sensors, an interpolation-based strain reconstruction approach is proposed.  相似文献   

A fully coupled elastic–plastic hydromechanical model for compacted soils accounting for clay activity     

Gabriele Della Vecchia  Enrique Romero 《国际地质力学数值与分析法杂志》2013,37(5):503-535

A constitutive model, accounting for multiphase and multiscale coupling, is proposed for the water retention domain and the stress–strain response of compacted clayey soils. The model is based on a conceptual interpretation of the microfabric evolution of compacted soils along generalised hydromechanical paths, detected by means of mercury intrusion porosimeter tests. Multiphase coupling is provided by the mutual interaction between the mechanical and the hydraulic states. Multiscale coupling is introduced by a measure of the size of the aggregates, which influences both the retention and the stress–strain response, in the phenomenological constitutive equations. Model capabilities are verified by comparison with relevant experimental data from laboratory tests on compacted Boom clay and other selected experimental data on different compacted clayey soils. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

Physical-Ecological Response of the California Current System to ENSO events in ROMS-NEMURO     

Cordero-Quirós  Nathalí  Miller  Arthur J.  Pan  Yunchun  Balitaan  Lawrence  Curchitser  Enrique  Dussin  Raphael 《Ocean Dynamics》2022,72(1):21-36

Ocean Dynamics - We analyze the bottom-up El Niño/Southern Oscillation (ENSO) driven physical-biological response of the California Current System (CCS) in a high-resolution,...  相似文献   

Cloud-to-ground lightning and Mesoscale Convective Systems     

Enrique V. Mattos  Luiz A.T. Machado 《Atmospheric Research》2011,99(3-4):377-390

This work analyzes some physical and microphysical properties of Mesoscale Convective Systems (MCSs) and cloud-to-ground lightning. Satellite data from the GOES-10 infrared and NOAA-18 and TRMM microwave channels and lightning information from the Brazilian lightning detection network (BrasilDAT) were utilized for the period from 2007 to 2009. Based on an automatic MCSs detection method, 720 MCSs life cycles were identified during the period and in the region of study, with a lightning detection efficiency of over 90%. During the diurnal cycle, maximum electrical activity occurred close to the time of maximum convective cloud fraction (18 UTC), and 3 h after the maximum normalized area expansion rate. Diurnal cycles of both properties were modulated by diurnal heating, and thus could be used to monitor diurnal variability of lightning occurrence. The electrical activity was more intense for the widest (Pearson’s correlation of 0.96) and deeper (Pearson’s correlation of 0.84) clouds, which reached 390 km size and 17 km maximum cloud top height. Area growth during the initial phase of MCSs exerted a strong influence on their size and duration, and thus also showed a potential for defining the possibility of electrical activity during their life cycle. The average lightning life cycle exhibited a maximum close to MCSs maturation, while the maximum average lightning density occurred in the MCSs initial life cycle stage. The growth rate of electrical activity during the early stages can indicate the strength of convection and the possible duration of systems with lightning occurrence. Strong condensation processes and mass flux during the growth phase of the systems can provide favorable conditions for cloud electrification and lightning occurrence. A comparison of high microwave frequencies with lightning data showed a strong relationship of vertically integrated ice content and particle size with lightning occurrence, with Pearson's correlation of 0.86 and 0.96, respectively. The polarization difference in the 85 GHz channel showed that electrical activity increases linearly with polarization reduction, associated with a high value of Pearson's correlation coefficient (above 0.90). This suggests that regions with more intense electrical activity are predominantly located in areas with a high concentration of larger ice particles that are vertically oriented, due to the existence of intense updrafts and the electric field. These results demonstrate the potential use of thermodynamic, dynamic and microphysical characteristics for analyzing thunderstorms severity, and as additional information for nowcasting and monitoring electrical activity over large regions that lack ground-based lightning sensors.  相似文献   

Regional modeling of dry spells over the Iberian Peninsula for present climate and climate change conditions   总被引：2，自引：0，他引：2  

Enrique Sánchez  Marta Domínguez  Raquel Romera  Noelia López de la Franca  Miguel Angel Gaertner  Clemente Gallardo  Manuel Castro 《Climatic change》2011,107(3-4):625-634

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Spartina densiflora demonstrates high tolerance to phenanthrene in soil and reduces it concentration     

Redondo-Gómez S  Andrades-Moreno L  Parra R  Valera-Burgos J  Real M  Mateos-Naranjo E  Cox L  Cornejo J 《Marine pollution bulletin》2011,62(8):1800-1808

The present study was conducted to investigate the tolerance of Spartina densiflora to phenanthrene, and to test its ability in phenanthrene dissipation. A glasshouse experiment was designed to investigate the effect of phenanthrene from 0 to 1000 mg kg⁻¹ on growth and photosynthetic apparatus of S. densiflora by measuring chlorophyll fluorescence parameters, gas exchange and photosynthetic pigments. We also performed chemical analysis of plant samples, and determined the concentration of phenanthrene remaining in soil. S. densiflora survived to concentrations as high as 1000 mg kg⁻¹ phenanthrene in soil; in fact, there was no significant difference in RGR among the treatments after 30 days. Otherwise, phenanthrene affected photosynthetic apparatus at 100 and 1000 mg kg⁻¹; thus, the lower Φ_PSII could be explained by the declined photosynthetic pigment concentrations. Soil extraction indicated a more marked rate of phenanthrene disappearance in the soil in the presence of S. densiflora.  相似文献   

TAPAS, a VO archive at the IRAM 30-m telescope     

Stephane Leon  Victor Espigares  José Enrique Ruíz  Lourdes Verdes-Montenegro  Rainer Mauersberger  Walter Brunswig  Carsten Kramer  Juan de Dios Santander-Vela  Helmut Wiesemeyer 《Experimental Astronomy》2012,34(1):65-88

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