Is delta-aminolevulinic acid dehydratase activity in bivalves from south-west Iberian Peninsula a good biomarker of lead exposure?     

Kalman J  Riba I  Blasco J  DelValls TA 《Marine environmental research》2008,66(1):38-40

The coast of Huelva is considered as a heavily contaminated area where the Tinto and Odiel rivers discharge after running through a metalliferous mining area in the Iberian Pyrite Belt and end in common estuary called Ría of Huelva. Lead is a highly toxic and widely distributed element in the aquatic environment; therefore there is a great interest in assessing the impact of this contaminant on aquatic organisms. To study the bioavailability and sources of lead, the bivalve species Chamelea gallina was collected from six sampling sites along the coast of Huelva. Besides the effect of this metal on the enzyme activity, delta-aminolevulinic acid dehydratase (ALA-D) was determined in the whole tissue. Results show the inverse relationship between the lead concentration and the activity of ALA-D measured in whole tissues (r2=0.7). Individuals collected from the Ría of Huelva estuary had the highest levels of total lead concentrations and the lowest activity of ALA-D. Lead isotope analyses demonstrated the different sources of lead contamination and also confirmed the influence of Ría of Huelva on the metal input to the marine environment.  相似文献   

On the use and abuse of Newton's second law for variable mass problems     

Angel R. Plastino  Juan C. Muzzio 《Celestial Mechanics and Dynamical Astronomy》1992,53(3):227-232

We clarify some misunderstandings currently found in the literature that arise from improper application of Newton's second law to variable mass problems. In the particular case of isotropic mass loss, for example, several authors introduce a force that actually does not exist.Facultad de Ciencias Astronómicas y Geofisicas de la Universidad Nacional de La PlataOn a Fellowship from the Comisión de Investigaciones Cientificas de la Provincia de Buenos Aires.Member of the Carrera del Investigador Cientifico del Consejo Nacional de Investigaciones Cientificas y Técnicas de la República Argentina.  相似文献   

Testing the applicability of a Marine Biotic Index (AMBI) to assessing the ecological quality of soft-bottom benthic communities, in the South America Atlantic region   总被引：2，自引：0，他引：2  

Muniz P  Venturini N  Pires-Vanin AM  Tommasi LR  Borja A 《Marine pollution bulletin》2005,50(6):624-637

Recently, several monitoring programmes have been undertaken to evaluate the impact of different anthropogenic activities, upon a range of coastal ecosystems located in the South-western Atlantic. In the present contribution, the applicability of the AZTI's Marine Biotic Index (AMBI) is tested, to establish the benthic health of the ecosystem using these data sets. As the AMBI was created previously for use in European estuarine and coastal environments, its general applicability to new geographical locations is discussed. In general, the results are in agreement with those obtained using traditional univariate and multivariate methods. Some inconsistent results are observed, when low abundances and/or number of taxa are recorded in the samples. Moreover, when the macrofauna samples are dominated by large nematodes, the classification of the benthic ecosystem health using AMBI is not consistent with previous results achieved applying other statistical techniques. Thus, parallel to the application of this index to a wider extend, the complementary use of different indices and/or methods is recommended to assess confidently the environmental quality of a coastal area.  相似文献   

Guidelines for the use of AMBI (AZTI's Marine Biotic Index) in the assessment of the benthic ecological quality   总被引：7，自引：0，他引：7  

Borja A  Muxika I;AZTI  Department of Oceonography  Marine Environment  Herrera Kaia  Portualdea sin Pasaia  Spain 《Marine pollution bulletin》2005,50(7):787-789

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Numerical solution of the dam failure problem by the random choice method     

Guillermo Marshall  Angel N. Menendez 《Advances in water resources》1981,4(3):125-133

A numerical solution of the dam failure problem as described by the one-dimensional shallow water equations is presented. The construction of the solution is based on the random choice method consisting in the superposition of locally theoretical solutions and sampling techniques. The search of the optimal sampling is performed through the application of the random choice method to the scalar wave equation. The dam failure problem is then solved and a comparison with the theoretical solution is presented. It is shown that the random choice method computes the bore with almost infinite resolution, represents exactly the constant state behind it and calculates the depression wave with great accuracy.  相似文献   

Extreme Climatic Events in Dendroclimatic Reconstructions from Spain     

Emilio Manrique  Angel Fernandez-Cancio 《Climatic change》2000,44(1-2):123-138

The analysis of series of climatic values for almost a millennium, obtained by dendroclimatic methods, makes evident the existence of values that are remarkably greater or smaller than the rest. The criterion to identify this type of values has been the distance to the mean of the climatic series, in units of the standard deviation: out-of-range values are those that differ from the mean in more than four standard deviations. The study of these values gives an original perspective of the climatic past in Spain, including the outstanding oscillations of the Little Ice Age (LIA). The unusual climatic conditions of the last decades are also detected using this method.  相似文献   

Bronze Age ceramics in southwest Spain: An exploratory archaeometric study of technology and function     

Angel Polvorinos del Río  Leonardo García Sanjun  Víctor Hurtado Prez  M. Jesús Hernndez Arnedo 《Geoarchaeology》2005,20(3):263-284

Pottery from the Bronze Age of southwest Spain has traditionally been approached from a “typological” stand seeking the establishment of chronological sequences. This article examines ceramics from two different Bronze Age sites, a settlement (El Trastejón) and a necropolis (La Traviesa), from an archaeometric viewpoint. The methodology involved includes mineralogical characterization by XRD and optical microscopy, chemical analysis by XRF, and morphometric analysis through digital processing of thin sections. The analytical results are contextualized within the general framework of our current archaeological knowledge of both sites and their general background, and then a preliminary interpretation is proposed in terms of the prehistoric technology of pottery manufacture and functionality. © 2005 Wiley Periodicals, Inc.  相似文献   

Changes in the storage and sink of carbon dioxide in subsurface atmospheres controlled by climate-driven processes: the case of the Ojo Guareña karst system     

Angel Fernandez-Cortes  Soledad Cuezva  Elena Garcia-Anton  Miriam Alvarez-Gallego  Concepcion Pla  David Benavente  Juan Carlos Cañaveras  Jose Maria Calaforra  David Paterson Mattey  Sergio Sanchez-Moral 《Environmental Earth Sciences》2015,74(12):7715-7730

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Implementation of the European Marine Strategy Framework Directive: a methodological approach for the assessment of environmental status, from the Basque Country (Bay of Biscay)     

Borja A  Galparsoro I  Irigoien X  Iriondo A  Menchaca I  Muxika I  Pascual M  Quincoces I  Revilla M  Germán Rodríguez J  Santurtún M  Solaun O  Uriarte A  Valencia V  Zorita I 《Marine pollution bulletin》2011,62(5):889-904

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Validation of Arenicola marina in field toxicity bioassays using benthic cages: biomarkers as tools for assessing sediment quality     

Ramos-Gómez J  Martins M  Raimundo J  Vale C  Martín-Díaz ML  DelValls TA 《Marine pollution bulletin》2011,62(7):1538-1549

Sediment toxicity assessments using caged organisms present advantages over using laboratory and native community studies. The use of caged Arenicola marina in sediment toxicity assessments was evaluated. Lugworms were exposed in situ to sediments from coastal and port areas in Spain for seven days, and the activities of the biotransformation enzymes ethoxyresorufin O-deethylase, dibenzylfluorescein dealkylase and glutathione S-transferase, the activities of the antioxidant enzymes glutathione reductase and glutathione peroxidase and lipid peroxidation were then analyzed as biomarkers. Biomarker results and sediment physicochemical data were integrated. Cádiz Bay (SW Spain) sediments presented metal contamination that was not linked to a biochemical response. In LPGC Port (SW Spain), Pb contamination exhibited a moderate toxic potential, while PAHs, and presumably pharmaceuticals, provoked biochemical responses that efficiently prevented lipid peroxidation. In Santander Bay (N Spain), exposure to PAHs and, presumably, pharmaceuticals induced biomarker responses, but lipid peroxidation occurred nevertheless. These results indicated that caged A. marina were effective for the assessment of sediment quality and that the selected biomarkers were sufficiently sensitive to identify chemical exposure and toxicity.  相似文献