A note on a mineralogical analysis of the sediments associated with the Plata River and Patos Lagoon outflows     

Edmo J.D. Campos  Swapna Mulkherjee  Alberto R. Piola  Flavio M.S. de Carvalho 《Continental Shelf Research》2008

Riverine waters bring to seas a variety of suspended materials, which are ultimately deposited on the shelf or exported to the deep ocean. Investigation of the mineralogical contents of these continental-borne constituents on seafloors may reveal valuable information about the environmental conditions in the drainage basin. In this note we report results of X-ray diffraction and other analysis of sediments in bottom samples collected on the continental shelf under influence of the Plata River and the Patos Lagoon, in South America. The analysis reveals that non-clay materials are mostly concentrated south of 33°S, while clay sediments are relatively more abundant further north. We propose that such distributions are controlled by the circulation pattern and water mass distribution of the lower and upper layers, respectively.  相似文献   

Comparison between the indirect approach and kriging with samples of different support for estimation using samples of different length     

Marcel?Antonio?Arcari?BassaniEmail author  Jo?o?Felipe?Coimbra?Leite?Costa  Waleska?Campos?Guaglianoni  Ricardo?Hundelshaussen?Rubio 《Stochastic Environmental Research and Risk Assessment (SERRA)》2018,32(3):785-797

In this paper we compare two estimation methods to deal with samples of different support: (1) the indirect approach using accumulation and (2) kriging with samples of different support. These two methods were tested in a simple example. The estimates of the two methods were compared against a benchmark scenario. The benchmark consisted of kriging using a complete set of samples on the same support. The effects of the nugget effect, variogram range and type on the weight of long samples, the estimate, and the error variance were assessed. Kriging with samples of different support led to lower error variance and to estimates closer to the estimates of the benchmark scenario. Furthermore, in the case of spatially continuous attributes (low nugget effect), the indirect approach assigns greater weight to long samples than kriging with samples of different support. A cross validation study comparing the two methods with a database from a bauxite deposit was performed. The results of the cross validation study showed that kriging with samples of different support resulted in more precise estimates.  相似文献   

Ground motion scenarios consistent with probabilistic seismic hazard disaggregation analysis. Application to Mainland Portugal     

Maria Luísa Sousa  Alfredo Campos Costa 《Bulletin of Earthquake Engineering》2009,7(1):127-147

Probabilistic seismic hazard for Mainland Portugal was re-evaluated in order to perform its disaggregation. Seismic hazard was disaggregated considering different spaces of random variables, namely, univariate conditional hazard distributions of M (magnitude), R (source-to-site distance) and ε (deviation of ground motion to the median value predicted by an attenuation model), bivariate conditional hazard distributions of M–R and X–Y (seismic source latitude and longitude) or multivariate conditional hazard distributions of M–R–ε and M–(X–Y)–ε. The main objective of the present work was achieved, as it was possible, based on the modal values of the above mentioned distributions, to characterize the scenarios that dominate some seismic hazard levels of the 278 Mainland Portuguese counties. In addition, results of 4D disaggregation analysis, in M–(X–Y)–ε, pointed out the existence of one geographic location shared by the dominant scenario of most analyzed counties, especially for hazard levels correspondent to high return periods. Those dominant scenarios are located offshore at a distance of approximately 70 km WSW of S. Vicente cape. On the other hand, the lower the return period the higher is the number of modal scenarios in the neighbourhood of the analyzed site. One may conclude that modal scenarios reproduce hazard target values in each site with great accuracy enabling the applications derived from those scenarios (e.g. loss evaluation) to be associated to a hazard level exceedance probability.  相似文献   

On the Applicability of Joint Inversion of Gravity and Resistivity Data to the Study of a Tectonic Sedimentary Basin in Northern Portugal     

Patricia Represas  F. A. Monteiro Santos  Joana A. Ribeiro  A. Andrade Afonso  José Ribeiro  Mário Moreira  L. A. Mendes-Victor 《Pure and Applied Geophysics》2015,172(10):2681-2699

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Shakbazian Compact Groups: Mass‐to‐light ratios and mass distribution models: I. ShCG 362 and ShCG 166     

G. Gimeno  M. Campos  R. Díaz  J. Caldern 《Astronomische Nachrichten》2007,328(9):972-982

We present results of photometric observations under excellent seeing conditions of Shakbazian Compact Groups. We obtained the seeing‐unconvolved surface brightness profiles of individual galaxies in the I band. We also determined the B – I color index for each galaxy, and investigated the presence of cores in the early type galaxies. We constructed models for the mass distribution of the individual galaxies. The mass‐to‐light (𝔐/L) ratios have normal values, and the conclusion that these groups have little dark matter is confirmed. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

Science of Nowcasting Olympic Weather for Vancouver 2010 (SNOW-V10): a World Weather Research Programme Project     

G. A. Isaac  P. I. Joe  J. Mailhot  M. Bailey  S. Bélair  F. S. Boudala  M. Brugman  E. Campos  R. L. Carpenter Jr.  R. W. Crawford  S. G. Cober  B. Denis  C. Doyle  H. D. Reeves  I. Gultepe  T. Haiden  I. Heckman  L. X. Huang  J. A. Milbrandt  R. Mo  R. M. Rasmussen  T. Smith  R. E. Stewart  D. Wang  L. J. Wilson 《Pure and Applied Geophysics》2014,171(1-2):1-24

A World Weather Research Programme (WWRP) project entitled the Science of Nowcasting Olympic Weather for Vancouver 2010 (SNOW-V10) was developed to be associated with the Vancouver 2010 Olympic and Paralympic Winter Games conducted between 12 February and 21 March 2010. The SNOW-V10 international team augmented the instrumentation associated with the Winter Games and several new numerical weather forecasting and nowcasting models were added. Both the additional observational and model data were available to the forecasters in real time. This was an excellent opportunity to demonstrate existing capability in nowcasting and to develop better techniques for short term (0–6 h) nowcasts of winter weather in complex terrain. Better techniques to forecast visibility, low cloud, wind gusts, precipitation rate and type were evaluated. The weather during the games was exceptionally variable with many periods of low visibility, low ceilings and precipitation in the form of both snow and rain. The data collected should improve our understanding of many physical phenomena such as the diabatic effects due to melting snow, wind flow around and over terrain, diurnal flow reversal in valleys associated with daytime heating, and precipitation reductions and increases due to local terrain. Many studies related to these phenomena are described in the Special Issue on SNOW-V10 for which this paper was written. Numerical weather prediction and nowcast models have been evaluated against the unique observational data set now available. It is anticipated that the data set and the knowledge learned as a result of SNOW-V10 will become a resource for other World Meteorological Organization member states who are interested in improving forecasts of winter weather.  相似文献   

The Monitoring Network of the Vancouver 2010 Olympics   总被引：1，自引：0，他引：1  

Paul Joe  Bill Scott  Chris Doyle  George Isaac  Ismail Gultepe  Douglas Forsyth  Stewart Cober  Edwin Campos  Ivan Heckman  Norman Donaldson  David Hudak  Roy Rasmussen  Paul Kucera  Ron Stewart  Julie M. Thériault  Teresa Fisico  Kristen L. Rasmussen  Hannah Carmichael  Alex Laplante  Monika Bailey  Faisal Boudala 《Pure and Applied Geophysics》2014,171(1-2):25-58

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The infrared–X-ray continuum correlation in active galactic nuclei     

M. Contini  S. M. Viegas  P. E. Campos 《Monthly notices of the Royal Astronomical Society》2003,346(1):37-46

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Time-scales of recent Phlegrean Fields eruptions inferred from the application of a ‘diffusive fractionation’ model of trace elements   总被引：2，自引：1，他引：1  

Diego Perugini  Giampiero Poli  Maurizio Petrelli  Cristina P. De Campos  D. B. Dingwell 《Bulletin of Volcanology》2010,72(4):431-447

The variation of chemical element compositions in two pyroclastic sequences (Astroni 6 and Averno 2, Phlegrean Fields, Italy) is studied. Both sequences are compositionally zoned indicating a variability of melt compositions in the magma chamber prior to eruption. A clear dichotomy between the behaviour of major vs. trace elements is also observed in both sequences, with major elements displaying nearly linear inter-elemental trends and trace elements showing a variable scattered behaviour. Together with previous petrological investigations these observations are consistent with the hypothesis that magma mixing processes played a key role in the evolution of these two magmatic systems. Recently it has been suggested that mixing processes in igneous systems may strongly influence the mobility of trace elements inducing a ‘diffusive fractionation’ phenomenon, whose extent depends on the mixing time-scale. Here we merge information from 1) numerical simulations of magma mixing, and 2) magma mixing experiments (using as end-members natural compositions from Phlegrean Fields) to derive a relationship relating the degree of ‘diffusive fractionation’ to the mixing time-scales. Application of the ‘diffusive fractionation’ model to the two studied pyroclastic sequences allowed us to apply the relationship derived by numerical simulations and experiments to estimate the mixing time-scales for these two magmatic systems. Results indicate that mixing processes in Astroni 6 and Averno 2 systems lasted for approximately 2 and 9 days, respectively, prior to eruption.  相似文献   

Fish bile as a biomarker for metal exposure     

Hauser-Davis RA  Bastos FF  de Oliveira TF  Ziolli RL  de Campos RC 《Marine pollution bulletin》2012,64(8):1589-1595

Fish accumulate several trace elements in muscle, gills and liver, however studies also indicate that metals can be excreted through bile. Since metal contamination leads to modifications in bile composition, biliary excretion offers an alternative way to evaluate the presence of trace-elements. Bile is easier to obtain than other organs and presents a simpler matrix, making it easier for chemical pre-treatment. To verify if bile can be useful as a biomonitoring tool for metal contamination, liver and bile trace element concentrations were determined and correlated. The Artificial Neural Networks statistical technique was used to verify if liver trace-element quantification could be substituted by bile analysis. Results show that significant correlations were obtained between trace elements in bile and liver and the ANN validated the hypothesis that certain trace-elements in bile could be utilized instead of liver trace-elements. Further studies in this field are of interest to further validate this biomarker.  相似文献