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291.
Erdem Emin Maras Mustafa Caniberk Mehmet Serhat Odabas Burcu Degerli Süleyman Sirri Maras Hadi Hakan Maras 《Arabian Journal of Geosciences》2016,9(2):164
We investigated the relationships between mineral content and the physical and mechanical properties of landscape rock using a non-destructive remote sensing method applied in the laboratory. Using this technique, the spectral properties of the landscape rock could be collected at different wavelengths without harming the samples. Differences in spectral reflectance were compared with the physical and mechanical properties of the stone. Significant correlations were observed between reflectance values and the rocks’ mechanical and physical properties, with correlation coefficients of 95 to 99 %. However, establishing a correlation between two variables is not a sufficient condition to establish a causal relationship. Mineral densities and mineral content are characteristics used for the classification of landscape rock. We have concluded that although spectral signatures from landscape rock can be used for predicting which stones might have similar features when comparing two batches of stone, the high correlations we discovered cannot confirm a cause and effect relationship that would allow for the prediction of a rock’s physical and mechanical properties. Although this conclusion is disappointing, the mineral content and the significant correlations discovered by hyperspectral reflectance scanning can be used as supplementary information when comparing two samples of landscape rock. 相似文献
292.
We developed delta generalised additive models (GAMs) to predict the spatial distribution of different size classes of South African hakes, Merluccius capensis and M. paradoxus, using demersal trawl survey data and geographical (latitude and longitude) and environmental features (depth, temperature, bottom dissolved oxygen and sediment type). Our approach consists of fitting, for each hake size class, two independent models, a binomial GAM and a quasi-Poisson GAM, whose predictions are then combined using the delta method. Delta GAMs were validated using an iterative cross-validation procedure, and their predictions were then employed to produce distribution maps for the southern Benguela. Delta GAM predictions confirmed existing knowledge about the spatial distribution patterns of South African hakes, and brought new insights into the factors influencing the presence/absence and abundance of these species. Our GAM approach can be used to produce distribution maps for spatially explicit ecosystem models of the southern Benguela in a rigorous and objective way. Ecosystem models are critical features of the ecosystem approach to fisheries, and distribution maps constructed using our GAM approach will enable a reliable allocation of species biomasses in spatially explicit ecosystem models, which will increase trust in the spatial overlaps and, therefore, the trophic interactions predicted by these models. 相似文献
293.
Ridgeia piscesae是唯一一种存在于东北太平洋Juan de Fuca Ridge热液区的管状蠕虫,我们成功通过RACE PCR获得Ridgeia piscesae TAK1(Rp TAK1)基因全长c DNA序列.为深入研究TAK1基因在管状蠕虫中的作用,本文通过显微注射获得Rp TAK1转基因果蝇,并在果蝇体内成功过表达Rp TAK1基因.我们发现由Rp TAK1编码的氨基酸序列具有一定保守性,可能暗示其功能上的保守性,同时也暗示TAK1蛋白在物种进化中的保守性.而过表达突变体果蝇的眼睛出现变异,包括眼睛变得粗糙、单眼排列不整齐及整体形状变小,可以看出Rp TAK1基因影响果蝇的机体发育,我们猜测在Rp TAK1基因在管状蠕虫的生长发育过程中也可能起到重要作用. 相似文献
294.
Grajales-Nishimura José Manuel Ramos-Arias Mario Alfredo Solari Luigi Murillo-Muñetón Gustavo Centeno-García Elena Schaaf Peter Torres-Vargas Ricardo 《International Journal of Earth Sciences》2018,107(3):1005-1031
International Journal of Earth Sciences - The Juchatengo complex (JC) suite is located between the Proterozoic Oaxacan complex to the north and the Xolapa complex to the south, and was amalgamated... 相似文献
295.
Höhn Stefan Koglin Nikola Klopf Lisa Schüssler Ulrich Tragelehn Harald Frimmel Hartwig E. Zeh Armin Brätz Helene 《International Journal of Earth Sciences》2018,107(1):359-377
International Journal of Earth Sciences - Stratigraphically well-defined volcanic rocks in Palaeozoic volcano-sedimentary units of the Frankenwald area (Saxothuringian Zone, Variscan Orogen) were... 相似文献
296.
Ramacciotti Carlos D. Casquet César Baldo Edgardo G. Galindo Carmen Pankhurst Robert J. Verdecchia Sebastián O. Rapela Carlos W. Fanning Mark 《International Journal of Earth Sciences》2018,107(7):2605-2625
International Journal of Earth Sciences - The Western Sierras Pampeanas (WSP) of Argentina record a protracted geological history from the Mesoproterozoic assembly of the Rodinia supercontinent to... 相似文献
297.
Barbara A. Muhling Carlos F. Gaitán Charles A. Stock Vincent S. Saba Desiree Tommasi Keith W. Dixon 《Estuaries and Coasts》2018,41(2):349-372
Estuaries are productive and ecologically important ecosystems, incorporating environmental drivers from watersheds, rivers, and the coastal ocean. Climate change has potential to modify the physical properties of estuaries, with impacts on resident organisms. However, projections from general circulation models (GCMs) are generally too coarse to resolve important estuarine processes. Here, we statistically downscaled near-surface air temperature and precipitation projections to the scale of the Chesapeake Bay watershed and estuary. These variables were linked to Susquehanna River streamflow using a water balance model and finally to spatially resolved Chesapeake Bay surface temperature and salinity using statistical model trees. The low computational cost of this approach allowed rapid assessment of projected changes from four GCMs spanning a range of potential futures under a high CO2 emission scenario, for four different downscaling methods. Choice of GCM contributed strongly to the spread in projections, but choice of downscaling method was also influential in the warmest models. Models projected a ~2–5.5 °C increase in surface water temperatures in the Chesapeake Bay by the end of the century. Projections of salinity were more uncertain and spatially complex. Models showing increases in winter-spring streamflow generated freshening in the Upper Bay and tributaries, while models with decreased streamflow produced salinity increases. Changes to the Chesapeake Bay environment have implications for fish and invertebrate habitats, as well as migration, spawning phenology, recruitment, and occurrence of pathogens. Our results underline a potentially expanded role of statistical downscaling to complement dynamical approaches in assessing climate change impacts in dynamically challenging estuaries. 相似文献
298.
Automated Extraction of a Five‐Year LA‐ICP‐MS Trace Element Data Set of Ten Common Glass and Carbonate Reference Materials: Long‐Term Data Quality,Optimisation and Laser Cell Homogeneity
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LA‐ICP‐MS is increasingly applied to obtain quantitative multi‐element data with minimal sample preparation, usually achieved by calibration using reference materials (RMs). However, some ubiquitous RMs, for example the NIST SRM 61× series glasses, suffer from reported value uncertainties for certain elements. Moreover, no long‐term data set of analyses conducted over a range of ablation and tuning conditions exists. Thus, there has been little rigorous examination of the extent to which offsets between measured and reported values are the result of error in these values rather than analytically induced fractionation. We present new software (‘LA‐MINE’), capable of extracting LA‐ICP‐MS data with no user input, and apply this to our system, yielding over 5 years of data (~ 5700 analyses of ten glass and carbonate RMs). We examine the relative importance of systematic analytical bias and possible error in reported values through a mass‐specific breakdown of fourteen of the most commonly determined elements. Furthermore, these data, obtained under a wide range of different ablation conditions, enable specific recommendations of how data quality may be improved, for example the role of diatomic gas, the effect of differential inter‐glass fractionation factors and choice of transport tubing material. Finally, these data demonstrate that the two‐volume Laurin ablation cell is characterised by no discernible spatial heterogeneity in measured trace element ratios. 相似文献
299.
Ahmad Zalooli David Martín Freire-Lista Mashalah Khamehchiyan Mohammad Reza Nikudel Rafael Fort Shahram Ghasemi 《Environmental Earth Sciences》2018,77(8):315
Durability of building stones is an important issue in sustainable development. Crystallization of soluble salts is recognized as one of the most destructive weathering agents of building stones. For this reason, durability of Ghaleh-khargushi rhyodacite and Gorid andesite from Iran was investigated against sodium sulfate crystallization aging test. Petrographic and physico-mechanical properties and pore size distribution of these stones were examined before and after the aging test. The characteristics of the microcracks were quantified with fluorescence-impregnated thin sections. Durability and physico-mechanical characteristics of Ghaleh-khargushi rhyodacite are mainly influenced by preferentially oriented preexisting microcracks. Stress induced by salt crystallization led to the widening of preexisting microcracks in Ghaleh-khargushi rhyodacite, as confirmed by the pore size distributions before and after the aging test. The preexisting microcracks of Gorid andesite were attributed to the mechanical stress induced by contraction of lava during cooling. The number of transcrystalline microcracks was significantly increased after the aging test. The degree of plagioclase microcracking was proportional to its size. Durability of the studied stones depends on initial physico-mechanical properties, pore size distribution, and orientation of microcracks. Initial effective porosity is found to be a good indicator of the stones’ durability. Salt crystallization resulted in an increase in the effective porosity with a parallel decrease in the wave velocities. Surface microroughness parameters increased with the development of salt crystallization-induced microcracking. Gorid andesite showed higher quality and durability than Ghaleh-khargushi rhyodacite. 相似文献
300.
Assessment of the acid drainage neutralization capacity and the toxic metals lixiviation of tailing from Guanajuato mining district,Mexico 总被引:1,自引:0,他引:1
María Elena García-Arreola Luisa María Flores-Vélez Marcos Loredo-Tovías Alfredo Aguillón-Robles Rubén Alfonso López-Doncel Irene Cano-Rodríguez Sonia Hortensia Soriano-Pérez 《Environmental Earth Sciences》2018,77(9):355
In Mexico, many environmental problems are generated by large mining activities taking place in several mining districts. These mining activities produce great quantities of residues; large majorities of these have high sulfur content, which could generate acid drainage due to their interaction with the oxygen in the environment. The study area was located in the Mining District of Guanajuato, Mexico with abandoned tailings generated mainly by the gold and silver production. Two areas, called as Monte de San Nicolás (SN) and Peregrina (P) were selected for this study. The results study shows that there was no risk of production of acid drainage, since these tailings contained high amount of carbonates, which neutralized the generation of acidity and consequently decreased the possibility of leaching of some elements. However, not all elements leach in acid pH, as arsenic bound to oxyhydroxides, which is in a basic environment and its increased release by increasing the pH. 相似文献