Gypsum karst evolution in a diapir: a case study (Pinoso,Alicante, Spain)     

Tomás Rodríguez-Estrella  Antonio Pulido-Bosch 《Environmental Earth Sciences》2010,59(5):1057-1063

Gypsum deposits are highly soluble, and can undergo rapid weathering, especially where water intervenes, though certain human activities can accelerate the karstification processes. An example of karst formed in gypsum at Pinoso (Alicante, Spain) is analysed to show how human activity has impacted on its evolution. The karst here is associated with a huge diapir in the Triassic terrain that boasts of a large number of highly unusual exokarstic landforms. Here, rock salt has been extracted commercially for over 25 years using solution mining via deep boreholes. The brine extracted contains in excess of 300 g/L; over the whole period, more than 12 million tonnes of salt have been extracted using this method. After preliminary treatment to remove impurities, it travels along a brine pipeline to the coast. The enormous volume of the voids generated have probably favoured the acceleration of certain exokarstic and endokarstic processes.  相似文献   

Impacts of in-stream aggregate mining on the distributary channels of the alluvial fans of Tafí valley (Northwest Argentina)     

María Marta Sampietro-Vattuone  José Luis Peña-Monné  Graciela Rodríguez  Paula Lucía Medina  Marta Amelia Vattuone 《地球表面变化过程与地形》2021,46(14):2930-2945

In-stream mining is a common aggregate mining practice around the world. However, the impacts of such practice are not always taken into account when the mines are established, and the environmental cost of in-stream aggregate mining is generally not assessed. The purpose of this study was to evaluate the impacts of aggregate mining conducted in La Puerta River (Tafí valley, Northwest Argentina), a dry-pit in-stream mine, by considering the geomorphological, geoarchaeological, and human effects. Multitemporal analysis of the area using remote sensors (aerial photographs and satellite images 1970–2020), high-resolution drone digital elevation models and orthomosaics (2018–2019), and an intensive survey demonstrated that the mining area grew exponentially between 2002 and 2020 under unregulated mining. As a result, this practice exerts great environmental impact, including channel section alterations and destabilization of riverbanks, soil loss, river profile changes, and the formation of lag deposits of discarded materials, thus increasing environmental hazard under unpredictable flows. Finally, this is a highly touristic area that has suffered substantial landscape degradation and irreversible archaeological damage.  相似文献   

Confounding response of macrofauna from a confluence of impacts: brine and sewage pollution     

Rodrigo Rier  Fernando Tuy  Myriam Rodr&#;guez  &#;scar Monterroso  Eva Ramos 《海洋学报(英文版)》2013,32(10):74-81

Throughout the shores of the world,a confluence of different sources of pollution is common,e.g.,through outlets releasing brine,industrial,and domestic sewage.In this study,we assessed whether a combined disposal of domestic sewage and brine altered the patterns of abundance and assemblage structure of subtidal macrofauna inhabiting sandy seabeds on the south coast of Gran Canaria(Canary Islands,NE Atlantic Ocean).Samples were collected in two surveys(May 2008 and January 2009)at three distances(0,15,and30 m)away from the discharge point.Macrofaunal abundances showed different patterns with varying proximity from the disposal point in the two surveys.In May 2008,lower abundances were observed at0 m(53.89±46.82 ind.)than at 15 m(120±91.7 ind.)and 30 m(283.89±189.33 ind.)away from the disposal point.In January 2009,however,higher abundances were observed at 0 m(131.33±58.69 ind.)than at 30 m(100±24.44 ind.)and 15 m(84.78±58.39 ind.)away from the disposal point.Significant differences in macrofaunal assemblage structure were found with varying proximity from the discharge point in both surveys.The effect of proximity from the disposal point was confounded by changes in sedimentary composition between surveys,which contributed to explain differences in macrofaunal abundances and assemblage structure with varying proximity from the discharge point.As a result,confounding drivers of macrofaunal assemblage structure,here,changes in sediment composition,accounted for changes in macrofaunal abundances and assemblage structure with varying proximity from a combined disposal point of brine and sewage.  相似文献   

Selected contributions from the 6th Spanish Conference on Coastal Geomorphology, 7–9 September 2011, Tarragona, Spain: an introduction     

Isabel Montoya Montes  Maria J. Sánchez García  Inmaculada Rodríguez Santalla 《Geo-Marine Letters》2013,33(2-3):95-99

This special issue of Geo-Marine Letters presents selected contributions from the 6th Spanish Conference on Coastal Geomorphology held from 7–9 September 2011 in Tarragona, Spain. The guest editors are Isabel Montoya Montes, Maria J. Sánchez García and Inmaculada Rodríguez Santalla. These conferences on coastal geomorphology are held biannually and serve as a discussion forum focusing mainly on advances in knowledge about the dynamics of the Spanish littoral environment, although contributions from other coastal regions are encouraged. The papers presented in this Special Issue provide a selective view of the latest research results, the main topics dealing with recent coastal morphodynamics and longer-scale coastal evolution. The 7th Conference will be held in July 2013 in Oviedo, Spain, organized by the Department of Geology at the University of Oviedo.  相似文献   

Interacting Kasner-type cosmologies     

Mauricio Cataldo  Fabiola Ar��valo  Patricio Mella 《Astrophysics and Space Science》2011,333(1):287-293

It is well known that Kasner-type cosmologies provide a useful framework for analyzing the three-dimensional anisotropic expansion because of the simplification of the anisotropic dynamics. In this paper relativistic multi-fluid Kasner-type scenarios are studied. We first consider the general case of a superposition of two ideal cosmic fluids, as well as the particular cases of non-interacting and interacting ones, by introducing a phenomenological coupling function q(t). For two-fluid cosmological scenarios there exist only cosmological scaling solutions, while for three-fluid configurations there exist not only cosmological scaling ones, but also more general solutions. In the case of triply interacting cosmic fluids we can have energy transfer from two fluids to a third one, or energy transfer from one cosmic fluid to the other two. It is shown that by requiring the positivity of energy densities there always is a matter component which violates the dominant energy condition in this kind of anisotropic cosmological scenarios.  相似文献   

Highly radiative shock experiments driven by GEKKO XII     

A. Dizi��re  C. Michaut  M. Koenig  C. D. Gregory  A. Ravasio  Y. Sakawa  Y. Kuramitsu  T. Morita  T. Ide  H. Tanji  H. Takabe  P. Barroso  J.-M. Boudenne 《Astrophysics and Space Science》2011,336(1):213-218

In this paper, recent results obtained on highly radiative shocks generated in a xenon filled gas cell using the GEKKO XII laser facility are presented. Data show extremely high shock velocity (??150 km/s) never achieved before in gas. Preliminary analyses based on theoretical dimensionless numbers and numerical simulations suggest that these radiative shocks reach a new radiative regime where the radiative pressure plays a role in the dynamics and structure of the shock. A major effect observed is a strong anisotropic emission in the downstream gas. This unexpected feature is discussed and compared to available 2D radiation hydrodynamic simulations.  相似文献   

Diagnostics for regions of formation of atomic lines in stellar atmospheres     

O. Cardona  A. Flores  L. H. Rodrígues-Merino 《Astrophysics》2011,54(4):538-547

We present a procedure to make direct diagnostics of the physical conditions of the regions of formation of the atomic spectral lines in stellar atmospheres using the atomic line widths at half maximum and the number of lines visible of a given atomic series in the observed stellar spectra. This is accomplished using the theoretical widths at half maximum of the atomic lines induced by the broadening produced by thermal energy fluctuations and considering the maximum number of levels that exist in those atoms under the physical conditions of the given system. The procedure is easy to use in any application. As an example we apply the procedure to the observed Lyman lines of hydrogen in the ultraviolet of some stars.  相似文献   

A multi-model approach to the Atlantic Equatorial mode: impact on the West African monsoon   总被引：2，自引：0，他引：2  

T. Losada  B. Rodríguez-Fonseca  S. Janicot  S. Gervois  F. Chauvin  P. Ruti 《Climate Dynamics》2010,35(1):29-43

This paper is focused on the West African anomalous precipitation response to an Atlantic Equatorial mode whose origin, development and damping resembles the observed one during the last decades of the XXth century. In the framework of the AMMA-EU project, this paper analyses the atmospheric response to the Equatorial mode using a multimodel approach with an ensemble of integrations from 4 AGCMs under a time varying Equatorial SST mode. The Guinean Gulf precipitation, which together with the Sahelian mode accounts for most of the summer West African rainfall variability, is highly coupled to this Equatorial Atlantic SST mode or Atlantic Niño. In a previous study, done with the same models under 1958–1997 observed prescribed SSTs, most of the models identify the Equatorial Atlantic SST mode as the one most related to the Guinean Gulf precipitation. The models response to the positive phase of equatorial Atlantic mode (warm SSTs) depicts a direct impact in the equatorial Atlantic, leading to a decrease of the local surface temperature gradient, weakening the West African Monsoon flow and the surface convergence over the Sahel.  相似文献   

Constraints on Bose–Einstein condensate stars as neutron stars models from new observational data     

Adriel E. Rodríguez Concepción  Gretel Quintero Angulo 《Astronomische Nachrichten》2024,345(2-3):e240009

We evaluate the feasibility of Bose–Einstein condensate stars (BECS) as models for the interior of neutron stars (NSs). BECS are compact objects composed of bosons, formed through the spin-parallel pairing of neutrons. Here, we utilize the astronomical data from GW170817, XMMU J173203.3-344518 (the lightest NS known), and a novel lower limit on NS core heat capacity to scrutinize the compatibility of BECS with these recent observations of NSs. Our specific focus is to constrain the values of the scattering length $a$, parameter determining the strength of particle interactions in the model. Our analysis suggests that if the stars involved in GW170817 were BECSs, the scattering length of their constituent bosons should fall within the $4$ to $10$ fm range. Additionally, at a scattering length of $a\sim 3.1-4$ fm, stars with mass and radius characteristics akin to XMMU J173203.3-344518 are identified. Moreover, we find that the heat capacity depends on the mass and temperature of BECS, and surpasses the established lower bound for NS cores when $a>2-5$ fm. In summary, our results endorse BECS models with $a\sim 4$ fm, providing NS observables in agreement with diverse observations and contributing to the understanding of NS interiors.  相似文献   

Trends in warm days and cold nights over the Iberian Peninsula: relationships to large-scale variables     

Concepción Rodríguez-Puebla  Ascensión H. Encinas  Luis Alberto García-Casado  Susana Nieto 《Climatic change》2010,100(3-4):667-684

The aims of this study are to identify the trend of warm days and cold nights over the Iberian Peninsula and to connect the variations with large-scale variables. The reasons for performing this analysis are the effects that extremes events have on different ecosystems. Here, we present the results on spatial and temporal variability of warm days (TX90), or those exceeding the 90th percentile of maximum temperature, and cold nights (TN10), or those falling below the 10th percentile of minimum temperature. The extreme indices were derived from daily observations at stations and gridded data over land area for the period 1950 to 2006. Significant trends of more warm days and fewer cold nights were found. The trend to fewer cold nights is within the interval of global results given by the IPCC AR4 report; however, the trend to warm days is greater than the corresponding global trend. The influence of large-scale variables on these extreme indices was examined by means of the Empirical Orthogonal Function, correlation, composite maps and multiple regression analyses. Changes in TX90 are connected with the Scandinavian teleconnection index and a preferred mode of geopotential height at 500 hPa over the North Atlantic. Changes in TN10 are connected with the East Atlantic teleconnection index and the leading mode of Sea Surface Temperature (SST) variability over the North Atlantic area. Based on the links between the extreme indices and the large-scale variables we derived statistical models to describe the response of TX90 and TN10 to atmospheric circulation and SST variations. The models characterized the observed variations of TX90 and TN10 reasonably well. The results of this study encourage us to analyze, in further work, how temperature extremes might change over the Iberian Peninsula under warmer climate conditions.  相似文献