Phase shifts between colours in pulsating stars     

R. Garrido  E. Rodríguez 《Astrophysics and Space Science》1990,169(1-2):205-209

Observational evidence is presented showing that the time of maximum light for pulsating stars depends on observed wavelength. This fact is well explained by assuming that starlight variations comets from both temperature and gravity variations. Conversely, from the time shifts between two colours, temperature and gravity variations can be derived, together with the phase lag between them.Partially based on observations collected at European Southern Observatory, La Silla, Chile.Paper presented at the 11th European Regional Astronomical Meetings of the IAU on New Windows to the Universe, held 3–8 July, 1989, Tenerife, Canary Islands, Spain.  相似文献   

Data acquisition interfaces for GHRIL ITV-IPD detectors     

L. F. Rodríguez-Ramos  E. Ballesteros  J. C. González  C. Couros  J. J. Fuensalida 《Astrophysics and Space Science》1990,171(1-2):319-322

So as to meet the requirements of high spatial resolution techniques, two data acquisition interfaces for ITV and IPD detectors have been developed. These permit a synchronized and simultaneous observation between both of them. The synchronized temporal resolution is 20ms, as well as the data of the ITV, while the reading interface from the IPD permits a temporal resolution of 50s. The ITV signal is stored on the video-recorder while the IPD interface is developed through transputers which store the data, with the time tags, on computer disc.Paper presented at the 11th European Regional Astronomical Meetings of the IAU on New Windows to the Universe, held 3–8 July, 1989, Tenerife, Canary Islands, Spain  相似文献   

(Super) cosmological solution for the Kasner model     

A. Macías  O. Obregón 《Astrophysics and Space Science》1988,148(2):297-304

In the theory of supergravity (N=1), the supersymmetric version of general relativity, and for the Kasner cosmological model (Bianchi type I) we find a non-trivial solution (for the metric and spinor-vector) under the most simple assumption =₁₁ + ₂₂; ₁₂+₂₁=0 and for a special choosed gaugeN=1,N ^j=0, ₀=0. This method could be also applied to other cosmological metrics and extended to enlarged Grassmann basis.O. Obregón was partially supported by the Alexander von Humboldt Stiftung.  相似文献   

Rainfall intensity patterns derived from the urban network of Barcelona (NE Spain)     

Lana  Xavier  Serra  C.  Casas-Castillo  M. C.  Rodríguez-Solà  R.  Redaño  A.  Burgueño  A. 《Theoretical and Applied Climatology》2018,133(1-2):385-403

Theoretical and Applied Climatology - An analysis of the normalised rainfall intensity curves in Barcelona (NE Spain) has been undertaken from 41 selected rain rate episodes recorded by an urban...  相似文献   

Methodology for groundwater recharge assessment in carbonate aquifers: application to pilot sites in southern Spain   总被引：1，自引：0，他引：1  

B. Andreo  J. Vías  J. J. Durán  P. Jiménez  J. A. López-Geta  F. Carrasco 《Hydrogeology Journal》2008,16(5):911-925

Aquifer recharge can be determined by conventional methods such as hydrodynamic or hydrologic balance calculations, or numerical, hydrochemical or isotopic models. Such methods are usually developed with respect to detrital aquifers and are then used on carbonate aquifers without taking into consideration their hydrogeological particularities. Moreover, such methods are not always easy to apply, sometimes requiring data that are not available. Neither do they enable determination of the spatial distribution of the recharge. For eight regions in southern Spain, the APLIS method has been used to estimate the mean annual recharge in carbonate aquifers, expressed as a percentage of precipitation, based on the variables altitude, slope, lithology, infiltration landform, and soil type. The aquifers are representative of a broad range of climatic and geologic conditions. Maps of the above variables have been drawn for each aquifer, using a geographic information system; thus they can be superimposed to obtain the mean value and spatial distribution of the recharge. The recharge values for the eight aquifers are similar to those previously calculated by conventional methods and confirmed by discharge values, which corroborates the validity of the method.  相似文献   

Geology,fluid inclusion and sulphur isotope characteristics of the El Cobre VHMS deposit,Southern Cuba     

Xiomara Cazañas  Pura Alfonso  Joan Carles Melgarejo  Joaquín Antonio Proenza  Anthony Edward Fallick 《Mineralium Deposita》2008,43(7):805-824

The El Cobre deposit is located in eastern Cuba within the volcanosedimentary sequence of the Sierra Maestra Paleogene arc. The deposit is hosted by tholeiitic basalts, andesites and tuffs and comprises thick stratiform barite and anhydrite bodies, three stratabound disseminated up to massive sulphide bodies produced by silicification and sulphidation of limestones or sulphates, an anhydrite stockwork and a siliceous stockwork, grading downwards to quartz veins. Sulphides are mainly pyrite, chalcopyrite and sphalerite; gold occurs in the stratabound ores. Fluid inclusions measured in sphalerite, quartz, anhydrite and calcite show salinities between 2.3 and 5.7 wt% NaCl eq. and homogenisation temperatures between 177 and 300°C. Sulphides from the stratabound mineralisation display δ ³⁴S values of 0‰ to +6.0‰, whilst those from the feeder zone lie between −1.4‰ and +7.3‰. Sulphides show an intra-grain sulphur isotope zonation of about 2‰; usually, δ ³⁴S values increase towards the rims. Sulphate sulphur has δ ³⁴S in the range of +17‰ to +21‰, except two samples with values of +5.9‰ and +7.7‰. Sulphur isotope data indicate that the thermochemical reduction of sulphate from a hydrothermal fluid of seawater origin was the main source of sulphide sulphur and that most of the sulphates precipitated by heating of seawater. The structure of the deposit, mineralogy, fluid inclusion and isotope data suggest that the deposit formed from seawater-derived fluids with probably minor supply of magmatic fluids.  相似文献   

Testing spatial heterogeneity in geographically weighted principal components analysis     

Javier Roca-Pardiñas  Tomás R. Cotos-Yáñez  Rubén Pérez-Álvarez 《International journal of geographical information science》2017,31(4):676-693

We propose a method to evaluate the existence of spatial variability in the covariance structure in a geographically weighted principal components analysis (GWPCA). The method, that is extensive to locally weighted principal components analysis, is based on performing a statistical hypothesis test using the eigenvectors of the PCA scores covariance matrix. The application of the method to simulated data shows that it has a greater statistical power than the current statistical test that uses the eigenvalues of the raw data covariance matrix. Finally, the method was applied to a real problem whose objective is to find spatial distribution patterns in a set of soil pollutants. The results show the utility of GWPCA versus PCA.  相似文献   

The mercury problem in the Amazon due to gold extraction     

R.C. Villas Bas 《Journal of Geochemical Exploration》1997,58(2-3)

The environmental impacts caused by the use of mercury (Hg), as a gold (Au) amalgam, in gold extraction in three geographical areas located in the Brazilian wetlands (Poconé) and the Amazon (Alta Floresta and Itaituba), are reviewed and solutions proposed.  相似文献   

Hypothesis on the hydrogeological context of wetland areas and springs related to evaporitic karst aquifers (Málaga,Córdoba and Jaén provinces,Southern Spain)     

Bartolomé Andreo  José Manuel Gil-Márquez  Matías Mudarra  Luis Linares  Francisco Carrasco 《Environmental Earth Sciences》2016,75(9):759

  相似文献   

Physiological response to high temperature in the Tropical Eastern Pacific coral Pocillopora verrucosa          下载免费PDF全文

Alma P. Rodríguez‐Troncoso  Eugenio Carpizo‐Ituarte  Amílcar L. Cupul‐Magaña 《Marine Ecology》2016,37(5):1168-1175

The ecological and economic values of coral reef communities have encouraged efforts to implement periodic visual survey programs to secure their conservation. To date, visual monitoring‐based approaches have detected bleaching events weeks or months after the initial onset. An evaluation of the stress response of coral colonies, as well as their ability to resist and recover from the stress events, may increase our understanding of the physiological processes underling the stress and/or acclimation responses. Coral bleaching events, caused primarily by abnormally high temperatures, are continuously affecting coral communities worldwide. To evaluate the stress and recovery responses of the reef‐building coral Pocillopora verrucosa, a laboratory study was conducted herein. Coral nubbins were exposed to high temperatures to induce bleaching, and their ability to resist and recover from bleaching was subsequently monitored after returning the corals to ambient temperature. Lipid and chlorophyll concentrations, as well as Symbiodinium spp. density, decreased in samples exposed to nearly 31°C, slowly recovering to near‐control levels upon return to non‐stressful conditions. The present data set allows for an assessment of the vulnerability and ability of this common species to resist sub‐optimal environmental conditions, particularly the thermal stress events that will occur more commonly in their habitats as global seawater temperatures continue to rise.  相似文献