Multi-spectral decomposition of functional autoregressive models   总被引：2，自引：2，他引：0  

R. Salmerón  M. D. Ruiz-Medina 《Stochastic Environmental Research and Risk Assessment (SERRA)》2009,23(3):289-297

Functional data models provides a suitable framework for the statistical analysis of several environmental phenomena involving continuous time evolution and/or spatial variation. The functional autoregressive model of order p,  p ≥ 1, (FAR(p)) extends to the infinite-dimensional space context the classical autoregressive model AR(p) (see, for example, Mourid T (1993) Processus autorégressiifs d’ordre supérieur. Acad Sci t.317(Sér. I):1167–1172). In this paper, we derive a multidimensional diagonalization of the functional parameters (operators) involved in the FAR(p), p > 1, formulation. The functional state equation is then transformed into a discrete system of scalar state equations. The decomposition obtained is optimal regarding information on spatiotemporal interaction affecting the evolution of the spatial behavior of the process of interest. For functional prediction and filtering, we implement the Kalman filter equations from the diagonal version derived for FAR(p) models. This work has been supported in part by projects MTM2005-08597 of the DGI, MEC, and P05-FQM-00990, P06-FQM-02271 of the Andalousian CICE, Spain.  相似文献   

Degradation of Monoazo Pigments Red 53:1 and Red 48:2 by Fenton,Photo‐Fenton and UV/Peroxide Reactions     

Clóvis E. G. Ilha  Antônio J. M. G. dos Santos  Jurandir R. SouzaDe 《洁净——土壤、空气、水》2009,37(10):799-805

The degradation reactions of two monoazo pigments, namely, Red 53:1 and Red 48:2, by Fenton, photo‐Fenton and UV/H₂O₂ systems have been studied. The efficiencies of the Fenton reactions increased with temperature, but the formation of solid agglomerates was observed when the reactions were carried out above 50°C indicating a coagulant action of Fe⁺² or Fe⁺³. Photo‐Fenton reactions irradiated by sunlight presented the best rate constants for cleavage of the azo bond and the naphthalene rings. The UV/H₂O₂ system exhibited the highest efficiency with respect to the consumption of H₂O₂. The presence of a carbonyl group in the ortho position of the naphthol ring hampered the oxidation of pigment Red 48:2 by hydroxyl radicals. This finding may be explained in terms of the acceptor character of the COOH group, and suggests the formation of a complex containing two six‐membered rings between Fe⁺³ and the pigment molecule.  相似文献   

Synergic effect of salinity and light-chilling on photosystem II photochemistry of the halophyte,Sarcocornia fruticosa     

S. Redondo-Gómez  E. Mateos-Naranjo  M.E. Figueroa 《Journal of Arid Environments》2009,73(4-5):586-589

Laboratory experiments were conduced to assess the synergic effect of chilling and light on photosystem II photochemistry of the halophyte, Sarcocornia fruticosa, grown at different salinity concentrations (0, 170, 340, 510 and 1030 mM). Chlorophyll fluorescence was measured after chilling (at 5 °C in darkness) and light-chilling (at 5 °C and 700 μmol m^?2 s^?1) treatments, and after 24 h of recovery (at 20 °C and 75 μmol m^?2 s^?1). At 5 °C and 700 μmol m^?2 s^?1, plants grown with 0 and 170 mM NaCl showed the lowest F_v/F_m values, whereas quantum efficiency of PSII (Φ_PSII) was higher for plants grown at 170 and 340 mM NaCl, these results being consistent after two exposures to chilling treatments. Susceptibility to photoinhibition decreases when low temperature and high light are combined with high salinity. Therefore, populations of S. fruticosa that occur in arid environments with salinities c. 340 mM could show a higher tolerance to light-chilling.  相似文献   

Effect of burial on the germination of Opuntia tomentosa's (Cactaceae,Opuntioideae) seeds     

Y. Olvera-Carrillo  J. Márquez-Guzmán  M.E. Sánchez-Coronado  V.L. Barradas  E. Rincón  A. Orozco-Segovia 《Journal of Arid Environments》2009,73(4-5):421-427

Opuntia tomentosa seeds have physiological dormancy and a permeable but hard funicular envelope that restricts water uptake and embryo growth. Dormancy break, germination, and changes in the funiculus were compared in laboratory-stored seeds and in those buried for 7 months at different microsites and later exhumed and stored in the laboratory. The funicular envelopes of both lots were examined with a scanning electron microscope (SEM). Seeds in both lots were: scarified with H₂SO₄ (0, 45, 60 and 90 min), treated with gibberellins (0, 1000 and 2000 ppm) and germinated at the same ages (0, 2, 4, 7, and 10 months after exhumation) at 24 °C. Light effect was determined at 24 °C and 20–35 °C. In laboratory-stored seeds germination was low. Exhumed seeds germinated in ～50%, the remaining ones required scarification and gibberellins, but lost dormancy two months later. Gibberellins reduced germination heterogeneity, and scarification reduced germination; the adverse effect of scarification was offset by gibberellins. Exhumed seeds germinated mainly in darkness at 20–35 °C and partially in far red light at both temperatures. SEM showed that fungi eroded the funiculus reducing its resistance. O. tomentosa could form a seed bank, ensuring its survival under heterogeneous environments.  相似文献   

Combining 3D Hydraulic Tomography with Tracer Tests for Improved Transport Characterization          下载免费PDF全文

E. Sanchez‐León  C. Leven  C.P. Haslauer  O.A. Cirpka 《Ground water》2016,54(4):498-507

Hydraulic tomography (HT) is a method for resolving the spatial distribution of hydraulic parameters to some extent, but many details important for solute transport usually remain unresolved. We present a methodology to improve solute transport predictions by combining data from HT with the breakthrough curve (BTC) of a single forced‐gradient tracer test. We estimated the three dimensional (3D) hydraulic‐conductivity field in an alluvial aquifer by inverting tomographic pumping tests performed at the Hydrogeological Research Site Lauswiesen close to Tübingen, Germany, using a regularized pilot‐point method. We compared the estimated parameter field to available profiles of hydraulic‐conductivity variations from direct‐push injection logging (DPIL), and validated the hydraulic‐conductivity field with hydraulic‐head measurements of tests not used in the inversion. After validation, spatially uniform parameters for dual‐domain transport were estimated by fitting tracer data collected during a forced‐gradient tracer test. The dual‐domain assumption was used to parameterize effects of the unresolved heterogeneity of the aquifer and deemed necessary to fit the shape of the BTC using reasonable parameter values. The estimated hydraulic‐conductivity field and transport parameters were subsequently used to successfully predict a second independent tracer test. Our work provides an efficient and practical approach to predict solute transport in heterogeneous aquifers without performing elaborate field tracer tests with a tomographic layout.  相似文献   

Statistical Analysis of Palaeomagnetic Data from the Last Four Centuries: Evidence of Systematic Inclination Shallowing in Lava Flow Records     

F. J. Pavón-Carrasco  E. Tema  M. L. Osete  R. Lanza 《Pure and Applied Geophysics》2016,173(3):839-848

The main objective of this work is to compare directional (declination and inclination) volcanic and archaeomagnetic data for the last four centuries (~1600–1990) with the historical geomagnetic predictions given by the GUFM1 model which spans from 1590 to 1990. The results show statistical agreement between archaeomagnetic data and directions given by the geomagnetic field model. However, when comparing the volcanic data with the model predictions, marked inclination shallowing is observed. This systematically lower inclination has already been observed in local palaeomagnetic studies (Italy, Mexico and Hawaii) for the 20th century, by comparing recent lava flows with the International Reference Geomagnetic Field (IGRF) model. Here, we show how this inclination shallowing is statistically present at worldwide scale for the last 400 years with mean inclination deviation around 3° lower than the historical geomagnetic field model predictions.  相似文献   

Effects of Physical Processes and Sampling Resolution on Fault Displacement Versus Length Scaling: The Case of the Cantarell Complex Oilfield,Gulf of Mexico     

Shunshan Xu  Angel F. Nieto-Samaniego  Gustavo Murillo-Muñetón  Susana A. Alaniz-Álvarez  José M. Grajales-Nishimura  Luis G. Velasquillo-Martinez 《Pure and Applied Geophysics》2016,173(4):1125-1142

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Modeling the Crust and Upper Mantle in Northern Beata Ridge (CARIBE NORTE Project)   总被引：1，自引：0，他引：1  

Diana Núñez  Diego Córdoba  Mario Octavio Cotilla  Antonio Pazos 《Pure and Applied Geophysics》2016,173(5):1639-1661

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Multichannel Seismic Imaging of the Rivera Plate Subduction at the Seismogenic Jalisco Block Area (Western Mexican Margin)     

Rafael Bartolome  Estefanía Górriz  Juanjo Dañobeitia  Diego Cordoba  David Martí  Alejandra L. Cameselle  Francisco Núñez-Cornú  William L. Bandy  Carlos A. Mortera-Gutiérrez  Diana Nuñez  Arturo Castellón  Jose Luis Alonso 《Pure and Applied Geophysics》2016,173(10-11):3575-3594

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Field Survey of the 2015 Chile Tsunami with Emphasis on Coastal Wetland and Conservation Areas     

Manuel Contreras-López  Patricio Winckler  Ignacio Sepúlveda  Adolfo Andaur-Álvarez  Fernanda Cortés-Molina  Camila J. Guerrero  Cyntia E. Mizobe  Felipe Igualt  Wolfgang Breuer  José F. Beyá  Hernán Vergara  Rodrigo Figueroa-Sterquel 《Pure and Applied Geophysics》2016,173(2):349-367

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