Foraminifers and conodonts from the late Viséan to early Bashkirian succession in the Saharan Tindouf Basin (southern Morocco): biostratigraphic refinements and implications for correlations in the western Palaeotethys     

P. Czar  P. Medina‐Varea  I.&#x;D. Somerville  D. Vachard  S. Rodríguez  I. Said 《Geological Journal》2014,49(3):271-302

The Carboniferous succession in the Tindouf Basin of southern Morocco, North Africa, displays Mississippian to Early Pennsylvanian marine beds, followed by Pennsylvanian continental deposits. The marine beds comprise a shallow water cyclic platform sequence, dominated by shales and fine‐grained sandstones with thin but laterally persistent limestone/dolostone beds. Foraminiferal assemblages have been studied in the limestone beds in several sections from the Djebel Ouarkziz range in the northern limb of the Tindouf Syncline; they indicate that the age of the limestones range from late Asbian (late Viséan) to Krasnopolyanian (early Bashkirian). The foraminiferal assemblages are abundant and diverse, and much richer in diversity than those suggested by previous studies in the region, as well as for other areas of the western Palaeotethys. The richest assemblages are recorded in the Serpukhovian but, unusually, they contain several taxa which appear much earlier in Western European basins (in the latest Viséan). In contrast, conodont assemblages are scarce due to the shallow‐water facies, although some important taxa are recorded in the youngest limestones. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

A high-resolution operational forecast system for oil spill response in Belfast Lough     

Ana J. Abascal  Sonia Castanedo  Paula Núñez  Adam Mellor  Annika Clements  Beatriz Pérez  Mar Cárdenas  Helios Chiri  Raúl Medina 《Marine pollution bulletin》2017,114(1):302-314

This paper presents a high-resolution operational forecast system for providing support to oil spill response in Belfast Lough. The system comprises an operational oceanographic module coupled to an oil spill forecast module that is integrated in a user-friendly web application. The oceanographic module is based on Delft3D model which uses daily boundary conditions and meteorological forcing obtained from COPERNICUS and from the UK Meteorological Office. Downscaled currents and meteorological forecasts are used to provide short-term oil spill fate and trajectory predictions at local scales. Both components of the system are calibrated and validated with observational data, including ADCP data, sea level, temperature and salinity measurements and drifting buoys released in the study area. The transport model is calibrated using a novel methodology to obtain the model coefficients that optimize the numerical simulations. The results obtained show the good performance of the system and its capability for oil spill forecast.  相似文献   

Simultaneous phytoremediation of chromium and phenol by L<Emphasis Type="Italic">emna minuta</Emphasis> Kunth: a promising biotechnological tool     

C. E. Paisio  M. Fernandez  P. S. González  M. A. Talano  M. I. Medina  E. Agostini 《International Journal of Environmental Science and Technology》2018,15(1):37-48

The aim of this work was to evaluate the usefulness of Lemna minuta Kunth for the simultaneous removal of Cr(VI) and phenol. The impact of these contaminants on plant growth and some biochemical processes have also been discussed for a better understanding and utilization of this species in the field of phytoremediation. The optimal growth conditions and plant tolerance to Cr(VI) and/or phenol as well as removal were determined. Plants exposed to Cr(VI) and phenol were able to efficiently grow and remove both contaminants at high concentrations (up to 2.5 and 250 mg/L, respectively) after 21 days, indicating that they were resistant to mixed contamination. There were no significant differences between chlorophyll, carotene and malondialdehyde content of treated plants with respect to the controls, which would be due to an efficient antioxidant response. L. minuta showed a higher biomass than control without contaminant when was exposed to low concentrations of Cr(VI), suggesting an hormesis effect. The main removal process involved in chromium phytoremediation would be sorption or accumulation in the biomass. Moreover, our results suggest that phenol could be used as a donor of carbon and energy by these plants. These findings demonstrated that Lemna minuta Kunth might be suitable for treatment of different solutions contaminated with Cr(VI) and phenol, showing a high potential to be used in the treatment of effluents containing mixed contamination.  相似文献   

Interaction between magnetic clouds and the heliospheric current sheet at 1 AU as it is observed by one single observation point     

J.J. Blanco  M.A. Hidalgo  J. Rodriguez-Pacheco  J. Medina 《Journal of Atmospheric and Solar》2011,73(11-12):1339-1347

The effect of Magnetic Clouds (MCs) on the Heliospheric Current Sheet (HCS) local structure is yet an open question. Although it is widely accepted that a magnetic cloud has an important effect on the HCS shape, their structural relation, either the MC is part of the HCS or not, is not completely solved. Moreover, the problem grows up when trying to investigate three dimensional structures using one single observation point. We propose an approach to the MC–HCS study using magnetic models for the MC and local HCS structures, which are able of determining their relative orientation from one single spacecraft data. Three events have been selected in which an MC passage was observed close to HCS crossings. The results confirm the strong effect of MC passage on the HCS local orientation and they seem to be consistent with MCs propagating out of the HCS at 1 AU.  相似文献   

MEPBAY and SMC: Software tools to support different operational levels of headland-bay beach in coastal engineering projects     

André L.A. Raabe  Antonio H. da F. Klein  Mauricio González  Raul Medina 《Coastal Engineering》2010

This paper presents MEPBAY and SMC software tools that allow comprehending and solving problems in headland-bay beach through a parabolic model. These tools can be employed as coastal engineering design tools (including nourishment designs) and also for academic purposes. They are oriented to different end-users, including coastal technicians, scientists and undergraduates and as coastal engineering design tools, they can be applied to different operational levels (pre-design and design). The aim of the paper is to present design guidelines, the capabilities of the tools, their potential use and applications. Both tools were applied to analyze San Lorenzo Beach and demonstrate their ability at different project levels.  相似文献   

Influence of boundary conditions,specimen geometry and material heterogeneity on model calibration from triaxial tests     

Zenon Medina‐Cetina  Amy Rechenmacher 《国际地质力学数值与分析法杂志》2010,34(6):627-643

The recent capability of measuring full‐field deformations using advanced imaging techniques provides the opportunity to improve the predictive ability of computational soil mechanics. This paper investigates the effects of imperfect initial specimen geometry, platen‐soil and apparatus compliance, and material heterogeneity on the constitutive model calibration process from triaxial tests with nonlubricated platens. The technique of 3D‐Digital Image Correlation (3D‐DIC) was used to measure, from digital images, full‐field displacements over sand specimen surfaces throughout triaxial compression tests, as well as actual specimen initial shape, and deformations associated with platen and apparatus compliance and bedding settlement. The difference between predicted and observed 3D specimen surface deformations served to quantify an objective function in the optimization algorithm. Four different three‐dimensional finite element models (FEMs), each allowing varying degrees of material variability in the solution of the inverse problem, were used to study the effect of material heterogeneity. Results of the parametric study revealed that properly representing the actual initial specimen geometry significantly improves the optimization efficiency, and that accounting for boundary compliance can be critical for the accurate recovery of the full‐field experimental displacements. Allowing for nonsymmetric material variability had the most significant impact on predicted behavior. A relatively high coefficient of variation in model parameters was found among a statistical ensemble of tests, underscoring the importance of conducting multiple tests for proper material characterization. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

A contribution to the implementation of ICZM in the Mediterranean developing countries     

Pino González-Riancho  Marcello Sanò  Raúl Medina  Oscar García-Aguilar  Jurgi Areizaga 《Ocean & Coastal Management》2009,52(11):545-558

The purpose of this paper is to assess the level of implementation of Integrated Coastal Zone Management (ICZM) principles in the Mediterranean developing countries at the moment of signing the protocol on ICZM for the Mediterranean, in the framework of the UNEP Mediterranean Action Plan of the Barcelona Convention. This assessment is based on the results of two advanced seminars on ICZM promoted by the Azahar programme of the Spanish Agency for International Cooperation for the Development (Ministry of Foreign Affairs and International Cooperation). The contribution of the participants of the seminar, who are representatives of national agencies related with ICZM in different Mediterranean countries, have been collected through a questionnaire including: (i) a ranking of the main coastal sectors and the main coastal issues of each country; (ii) significant initiatives for the sustainable development of the Mediterranean coastal zones; and (iii) the evaluation of the ICZM progress. The state of the coast, the level of implementation of ICZM and the main problems faced to apply it, have been detected for each country. None of the consulted countries have a full implemented integrated coastal zone management, the major problems being: (i) the lack of financial commitment for the implementation of ICZM; (ii) the lack of an assessment and monitoring system; (iii) the lack of knowledge regarding the coastal system; (iv) the lack of qualified human resources; and (v) the lack of public participation and administrative integration strategies based on information. From these conclusions, some recommendations to improve ICZM are also provided. The work presented in this paper is the starting point to assess the evolution and the reference from which ICZM will be improved through the protocol on ICZM for the Mediterranean.  相似文献   

Comments on ‘numerical simulation of a random sea: a common error and its effect upon wave group statistics by M.J. Tucker,T.G. Challenor and D.J.T. Carter’     

Josep R. Medina  José Aguilar 《Applied Ocean Research》1985,7(2):113-114

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Comments on: “Artificial neural network to translate offshore satellite wave data to coastal locations, by R. Kalra, M.C. Deo, R. Kumar and V.K. Agarwal”: [Ocean Engineering 32 (2005) 1917–1932]     

Josep R. Medina   《Ocean Engineering》2006,33(14-15):2083-2085

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Morphodynamic classification of sandy beaches in low energetic marine environment   总被引：1，自引：0，他引：1  

L. Gómez-Pujol  A. Orfila  A. Alvarez-Ellacuria  R. Medina 《Marine Geology》2007,242(4):235-246

Morphodynamic classification of beaches has achieved widespread acceptance in both geological and geomorphological literature. In this sense, the present work classifies twelve Mediterranean low energetic beaches according to the dimensionless fall parameter (Ω) parameter in the Island of Mallorca. Propagation of 44 yr of wave data as well as a detailed sediment study allows to provide probabilities for morphodynamical beach state on an annual and seasonal basis. Consequently, beaches in Mallorca fall between three major categories which are (a) truly reflective, (b) reflective skewed to intermediate and (c) intermediate beaches. The Mallorcan beach position in the morphodynamical scheme is close related to the physiographical and geological framework. Comparison of observed values with those obtained in the analysis leads that for gross beach classification there is agreement between predicted and real state. However on a seasonal classification, mainly during summer, there is no agreement between the predicted state and the real one. As the model does not incorporate the role of summer sea breezes, beach reflective states are highlighted. Real beach configurations correspond to more energetic wave dynamic conditions and to intermediate state scenarios.  相似文献