Effect of incorrect interpretation of population statistics in the description of coral population dynamics: response to Crabbe 2009     

Ortiz JC 《Marine environmental research》2011,71(2):145-6; author reply 147-8

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Distribution of selected heavy metals in fluvial sediments of the coal mining region of Baixo Jacuí, RS, Brazil     

E. Teixeira  L. Ortiz  M. Alves  J. Sanchez 《Environmental Geology》2001,41(1-2):145-154

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Evolution of the Rotational State of Irregular Cometary Nuclei     

Gutiérrez  Pedro J.  Ortiz  José L.  Rodrigo  Rafael  López-Moreno  José J.  Jorda  Laurent 《Earth, Moon, and Planets》2002,90(1-4):239-247

A simplified thermal model has been used to calculate thenon-gravitational forces acting on small irregular nuclei in the orbit ofComet 46P/Wirtanen. The torque of thenon-gravitational force has beencalculated and the Euler equations have been solved in order toinvestigate the rotational evolution of several irregular nuclei duringa single orbital step. Several initial spin axis orientations andactivity patterns on their surfaces have been considered. The nucleiconsidered have a mean radius of 1 km and their inertia moments havebeen calculated assuming a homogeneous bulk density of 500 kg/m³. Inall the simulations, the initial spin period is 6h and the nucleiinitially rotate around their shortest axis. Under these assumptions,significant changes in the angular momentum and in spin period have beenobtained in all the simulations, but the nucleus is found to practicallyremain in its spin state of lowest energy during the entire orbitalperiod.  相似文献   

Jef Caers: Modeling Uncertainty in the Earth Sciences     

Julián M. Ortiz 《Mathematical Geosciences》2013,45(1):127-130

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Multivariate approach to estimate colour producing agents in Case 2 waters using first-derivative spectrophotometer data     

Khalid A. Ali  Donna L. Witter  Joseph D. Ortiz 《国际地球制图》2013,28(2):102-127

The complex composition and distribution of colour producing agents (CPAs) in turbid aquatic environments such as the Western Basin of Lake Erie (WBLE) presents a challenge to the application of remote sensing data for differentiating among in-water constituents and estimating their concentrations independently. In this study, multivariate procedures are applied to lab-based spectrophotometer data to estimate the concentration of chlorophyll-a and suspended matters in the WBLE. Principal Component Analysis of first-derivative transformed hyper-spectral data from the spectrophotometer extracted three significant spectral components for each cruise, explaining up to 88% of the spectral variability. Spectral matching using reference spectra indicated that two of the extracted patterns represent signatures of in-water constituents that govern the optical properties of the WBLE, namely, cyanobacteria and diatoms associated with green algae. The spectrophotometer data clearly revealed known spectral features associated with phytoplankton, such as the absorption minima near 550 and 700 nm, which can be attributed to the minimum of absorption and fluorescence of chlorophyll-a, respectively. The method also extracted the absorption peaks due to chlorophyll-a, near 670 nm, and due to phycocyanin, near 620 nm. Principal component regression of chlorophyll-a on the PC scores indicated that 63.4% of variation of chlorophyll-a in the WBLE can be explained by two components. Factors 2 and 3 explain 60% of the joint spatiotemporal variability of suspended matters in the WBLE. The results illustrate the potential of multivariate technique applied to remote sensing data in isolating the patterns that represent constituents in turbid Case 2 waters.  相似文献   

Simulation of Synthetic Exploration and Geometallurgical Database of Porphyry Copper Deposits for Educational Purposes     

Garrido  Mauricio  Sepúlveda  Exequiel  Ortiz  Julián  Townley  Brian 《Natural Resources Research》2020,29(6):3527-3545

Natural Resources Research - The access to real geometallurgical data is very limited in practice, making it difficult for practitioners, researchers and students to test methods, models and...  相似文献   

An open source,low cost video‐based coastal monitoring system     

M. A. Nieto  B. Garau  S. Balle  G. Simarro  G. A. Zarruk  A. Ortiz  J. Tintoré  A. Álvarez‐Ellacuría  L. Gómez‐Pujol  A. Orfila 《地球表面变化过程与地形》2010,35(14):1712-1719

A low cost, automated, remote monitoring video system built on standard commercial off‐the‐shelf (COTS) components and implemented with open source software is presented. The system has been implemented in a coastal area to perform image acquisition and processing, generating statistical products and transferring the information from the field to a central node where post‐processing and data visualization are made available to the general public. The open structure of the software allows the user to implement new routines and modules appropriate to fit specific needs as well as to adapt the system to study other dynamical processes where continuous observation is required. The software and image data base can be obtained as freeware. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

Study of the Contributions of Non‐Specific and Specific Interactions during Fluoxetine Adsorption onto Activated Carbons     

Silvia Román  João Manuel Valente Nabais  Juan Félix González  Carmen María González‐García  Angel Luis Ortiz 《洁净——土壤、空气、水》2012,40(7):698-705

The adsorption of fluoxetine onto activated carbons (ACs) prepared from almond tree pruning by steam and CO₂ activation under different temperature conditions (650–950°C), was studied. In both series increasing the temperature caused an increase in the BET apparent surface area, yielding ACs with S_BET up to 870 and 710 m² g^?1 after steam and CO₂ activation, respectively. Also, a slight widening of the porosity was found in both cases. In order to modify the functionality of the ACs, two of them were impregnated with triethylenediamine (TEDA) prior to the adsorption process, which caused a decrease in the AC apparent surface mainly due to micropore blockage. The fluoxetine adsorption isotherms at 25°C showed maximum adsorption capacities between 110 and 224 mg g^?1. The adsorption isotherms were analyzed using Langmuir and Freundlich models. Although the impregnation reduced the pore volume, it did not cause a decrease in the fluoxetine maximum adsorption capacity, but a modification in the adsorption mechanism was observed.  相似文献   

Interval‐Based Diagnosis of Biological Systems – a Powerful Tool for Highly Uncertain Anaerobic Digestion Processes     

Víctor Alcaraz‐González  Rubén Horacio López‐Bañuelos  Jean‐Philippe Steyer  Hugo Oscar Méndez‐Acosta  Víctor González‐Álvarez  Carlos Pelayo‐Ortiz 《洁净——土壤、空气、水》2012,40(9):941-949

Anaerobic digestion (AD) is a highly nonlinear time‐varying process commonly used for biological wastewater treatment, which is subject to large disturbances of both influent concentrations, and flow rates that may lead the process to a breakdown. In order to compensate the effect of these disturbances, the dynamics of the main state variables – including biomass – must be closely monitored and used to improve the process performance. However, AD processes still suffer from a lack of reliable and cheap sensors of key process variables to insure the right process operation. This has led to the development of estimation schemes, which infer the information of such key variables from the available measurements. Nevertheless, reliable measurements are not always possible to get because these readings may be corrupted by noise or erroneous due to sensor failures and as a consequence, they may lead to deteriorated control efforts and the eventual crash of the AD process. In this article, we propose an integrated system for the detection, isolation, and analysis of faults in AD processes by using interval observers (IO). The proposed approach was experimentally implemented on a 1‐m³ pilot scale anaerobic digester. Based on the comparison between the measured outputs and their corresponding estimates, results show that this approach was able to detect sensor failures as well as faults in the basic hypotheses made during the design step.  相似文献   

Crustal Architecture at the Collision Zone Between Rivera and North American Plates at the Jalisco Block: Tsujal Project     

Juanjo Dañobeitia  Rafael Bartolomé  Manel Prada  Francisco Nuñez-Cornú  Diego Córdoba  William L. Bandy  F. Estrada  Alejandra L. Cameselle  Diana Nuñez  Arturo Castellón  José Luis Alonso  Carlos Mortera  Modesto Ortiz 《Pure and Applied Geophysics》2016,173(10-11):3553-3573

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