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Transactions of Nonferrous Metals Society of China 2019年第1期29卷 34-42页

作者： Gloria ACOSTA lucien VElEVA juan luis lópez D.A.lópez-SAURI Applied Physics Department Research Center for Advanced Studies (CINVESTAV) Unidad Mérida Tecnológico Nacional de México Instituto Tecnológico de Mérida Departamento de Química y Bioquímica

Aluminum alloy samples, 6061-T6 and 2219-T42, were exposed to Caribbean seawater for 90 d. The fluctuations of open circuit potential, considered as electrochemical noise (EN), were used to characterize and compare initial pitting events, which appeared on their surfaces. EN analysis was carried out using the power spectral density (PSD) vs frequency. The decrease of the β exponent in PSD graphs indicated a release of spontaneous energy with the progress of pit formation in seawater. The fluctuations were associated with the breakdown and formation of new corrosion layers. The values of β exponent in PSD graphs suggest that corrosion process of AA2219-T42 alloy occurs as a persistent non-stationary process, the dynamics of which is controlled by fractional Brownian motion (fBm), while on AA6061-T6 alloy the corrosion process was dominated by stationary and weakly persistent features, with the contribution of fractional Gaussian noise (fGn). After the exposure in seawater, SEM-EDX analysis revealed insoluble intermetallic particles on the alloys, rich in Cu or Fe and irregularly distributed. The preferential dissolution of Mg and Al occurs from the S-phase (Al2CuMg) of AA2219-T42 alloy.

关键词： aluminum alloy corrosion electrochemical noise intermetallic particles seawater

Performance assessment of two-dimensional hydraulic models for generation of flood inundation maps in mountain river basins

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Water Science and Engineering 2019年第1期12卷 11-18页

作者： juan Pinos luis Timbe Department of Water Resources and Environmental Sciences University of Cuenca

Hydraulic models for the generation of flood inundation maps are not commonly applied in mountain river basins because of the difficulty in modeling the hydraulic behavior and the complex topography. This paper presents a comparative analysis of the performance of four twodimensional hydraulic models (HEC-RAS 2D, Iber 2D, Flood Modeller 2D, and PCSWMM 2D) with respect to the generation of flood inundation maps. The study area covers a 5-km reach of the Santa B-arbara River located in the Ecuadorian Andes, at 2330 masl, in Gualaceo. The model's performance was evaluated based on the water surface elevation and flood extent, in terms of the mean absolute difference and measure of fit. The analysis revealed that, for a given case, Iber 2D has the best performance in simulating the water level and inundation for flood events with 20- and 50-year return periods, respectively, followed by Flood Modeller 2D, HEC-RAS 2D, and PCSWMM 2D in terms of their performance. Grid resolution, the way in which hydraulic structures are mimicked, the model code, and the default value of the parameters are considered the main sources of prediction uncertainty.

关键词： Two-dimensional hydraulic models Flood modeling Flood extent Water surface elevation High mountain river Ecuador

Electrochemical and spectroscopic study of interfacial interactions between chalcopyrite and typical flotation process reagents

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International Journal of Minerals,Metallurgy and Materials 2016年第2期23卷 127-136页

作者： Gustavo Urbano Isabel lázaro Israel Rodríguez juan luis Reyes Roxana larios Roel Cruz Instituto de Metalurgia Universidad Autonotrla de San Luis PotosiAvSierra Leona 550Lomas 2a SeccionSan Luis PotosiS.L.P.78210Mexico Industrial Minera Mexico S.A.de C.V. San Luis PotosiS.L.P.Mexico Centro Universitario de Ciencias Exactas e Ingenierias Universidad de GuadalajaraGuadalajaraJaliscoMexico

Comparative voltammetry and differential double-layer capacitance studies were performed to evaluate interfacial interactions between cnalcopyrite（CuFeS2） and n-isopropyl xanthate（X） in the presence of ammonium bisulfite/39wt%SO2 and caustic starch at different pH *** spectroscopy,Fourier transform infrared（FTIR） spectroscopy,contact angle measurements,and microflotation tests were used to establish the type and extent of xanthate adsorption as well as the species involved under different mineral surface conditions in this *** results demonstrate that the species that favor a greater hydrophobicity of chalcopyrite are primarily CuX and S^0,whereas oxides and hydroxides of Cu and Fe as well as an excess of starch decrease the hydrophobicity.A conditioning of the mineral surface with ammonium bisulfite/39wt%SO2 at pH 6 promotes the activation of surface and enhances the xanthate ***,this effect is diminished at pH ≥ 8,when an excess of starch is added during the preconditioning step.

关键词： sulfide minerals chalcopyrite xanthates flotation interfacial reactions electrochemistry spectroscopy

Eucalyptus grandis plantations:effects of management on soil carbon,nutrient contents and yields

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Journal of Forestry Research 2020年第2期31卷 601-611页

作者： Diego Martin Sandoval lopez Marcelo Fabian Arturi juan Francisco Goya Carolina Alejandra Perez Jorge luis Frangi laboratorio de Investigacion de Sistemas Ecologicos y Ambientales(lISEA) Universidad Nacional de La PlataDiagonal 113 N°4691900 La PlataBuenos AiresArgentina

The expansion of fast-growing tree plantations is a worldwide process,with consequences on soil fertility and soil carbon *** results were found on the effects of afforestation with Eucalyptus on soil carbon and other nutrient *** discrepancies are usually caused by differences in climate,land use history,soil texture as well as by management related factors such as plantation age,number of rotations,method of establishment(plantation or coppice),harvest residue management and soil *** studied the effect of plantation age,number of rotations,and method of establishment on soils and plant nutrient concentrations in Eucalyptus grandis plantations in NE Argentina on different textured *** also determined if yields changed with nutrient variations in soils,and compared soils under plantations to soils under grasslands they ***-one *** stands of different ages,number of rotations and method of establishment were evaluated as well as eight grassland *** of carbon,nitrogen,phosphorus,potassium,calcium and magnesium were determined for soils and *** carbon and nitrogen decreased over the number of rotations and were more pronounced in soils with 50-60%sand than soils with>75%*** stands showed higher soil carbon and nitrogen levels than plantations,suggesting a negative effect of site preparation before planting on soil nutrient conservation,especially in fine-textured *** nutrient concentrations did not follow the trends observed for soil nutrients nor did they reflect nutrient *** was no evidence of decreased yields over successive *** carbon and nitrogen contents decrease when grasslands are replaced by *** plantations,and therefore a yield limitation may occur in a medium to long-term frame,especially in stands re-established for short-rotation *** residue management and site preparation must be specifically designed for improving so

关键词： Soil texture Grasslands Foliar nutrient concentrations Successive harvest Coppice Eucalyptus grandis

Symmetrization for Fractional Elliptic and Parabolic Equations and an Isoperimetric Application(Dedicated to Haim Brezis,great master of analysis,on his 70th birthday)

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Chinese Annals of Mathematics,Series B 2017年第2期38卷 661-686页

作者： Yannick SIRE juan luis VAZQUEZ Bruno VOlZONE johns hopkins university Krieger Hall3401 N.Charles StBaltimoreM D21218USA. departamento de matemticas universidad autnoma de madrid28049 M adridSpain dipartimento di ingegneria universit degli studi di napoli"parthenope"80143 Italia.

This paper develops further the theory of symmetrization of fractional laplacian operators contained in recent works of two of the authors. This theory leads to optimal estimates in the form of concentration comparison inequalities for both elliptic and parabolic equations. The authors extend the theory for the so-called restricted fractional laplacian defined on a bounded domain Ω of R^N with zero Dirichlet conditions outside of Ω. As an application, an original proof of the corresponding fractional Faber-Krahn inequality is derived. A more classical variational proof of the inequality is also provided.

关键词： Symmetrization, Fractional laplacian, Nonlocal elliptic and parabolicequations, Faber-Krahn inequality

Experimental analysis of infragravity waves in two eroded microtidal beaches

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Acta Oceanologica Sinica 2017年第5期36卷 31-43页

作者： MARIO Conde-Frias luis Otero juan Camilo Restrepo juan Carlos Ortiz Geosciences Research Group GE04 Department of PhysicsUniversidad del NorteBarranquilla 081007Colombia

This work aims to contribute to the characterization and understanding ofinfragravity waves on two beaches with erosion problems. For this reason, we have used an array of ADCP and a pressure sensor to measure wave parameters and pressure inside and outside of the surf zone during the dry and rainy period in the beaches of Galerazamba and Manzanillo del Mar （both dissipative and eroded beaches） located in the Colombian Caribbean coast. Based on these measurements, we have carried out a spectral analysis in order to identify the frequency components that characterize the wave and its energy; thus, we identified the characteristic frequencies of iufragravity waves to finally filter the infragravity signal on each beach in different seasonal periods. Among the results of the Welch spectrum applied to surface elevation time series, we found that, the frequencies＇ energy of the sea-swell band decreases due to bottom friction and wave breaking as the wave approaches the shore, while the frequencies＇ energy of the infragravity band increases significantly. In addition, for the wavelet analysis, we could observe how the energy of the infragravity band, especially the lowest frequencies gain energy as the waves approaches the coast. Furthermore, based on the infragravity wave obtained from the extreme wave event registered during the field campaign we can conclude that the contribution of this signal is important in the erosion problems presented in the beaches of Galerazamba and Manzanillo del Mar. Finally, these results show the need to realize other studies that allow us to understand deeply, the role of infragravity waves on the morphological changes that occurs in these beaches.

关键词： infragravity waves long waves experimental analysis fourier analysis wavelet transform

Identifcation of Immunity-related Genes in Arabidopsis and Cassava Using Genomic Data

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Genomics, Proteomics & Bioinformatics 2013年第6期11卷 345-353页

作者： luis Guillermo leal A'lvaro Perez Andre's Quintero A'ngela Bayona juan Felipe Ortiz Anju Gangadharan David Mackey Camilo lo'pez liliana lo'pez-Kleine Department of Statistics Universidad Nacional de Colombia Department of Biology Universidad Nacional de Colombia Department of Molecular Genetics The Ohio State University

Recent advances in genomic and post-genomic technologies have provided the opportu- nity to generate a previously unimaginable amount of information. However, biological knowledge is still needed to improve the understanding of complex mechanisms such as plant immune responses. Better knowledge of this process could improve crop production and management. Here, we used holistic analysis to combine our own microarray and RNA-seq data with public genomic data from Arabidopsis and cassava in order to acquire biological knowledge about the relationships between proteins encoded by immunity-related genes （IRGs） and other genes. This approach was based on a kernel method adapted for the construction of gene networks. The obtained results allowed us to propose a list of new IRGs. A putative function in the immunity pathway was predicted for the new IRGs. The analysis of networks revealed that our predicted IRGs are either well documented or recognized in previous co-expression studies. In addition to robust relationships between IRGs, there is evidence suggesting that other cellular processes may be also strongly related to immunity.

关键词： Arabidopsis Cassava Functional gene prediction Genomic data Kernel canonical correlation ajalysi Plant immunity

The political economy of city diplomacy

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Economic and Political Studies 2022年第2期10卷 228-249页

作者： juan luis Manfredi-Sanchez Department of International Studies&Journalism University of Castilla-La ManchaToledoSpain

City diplomacy is a major trend in the soft power *** cities face daily political issues deriving from globalisation(such as mass tourism,migration,climate change,and commodifi-cation of culture),they demand for,rather than contesting with a nationstate,an operational reinterpretation of sovereignty ori-ented to solve *** economy approach is a useful method to understand the role of global cities where the nation state has many *** global city establishes rules to influence international legal development and practice,even with-out a traditional legal basis(such as sovereignty,monopoly on violence,and legal exclusivity).As these‘superstar cities’grow,other cities are losing opportunities to develop and take advan-tage of *** risk of inter-urban inequality feeds *** will become the middle power in global political organisations in the future,and political economy will shed light on how power and values operate at the urban level.

关键词： City diplomacy leadership political economy sanctuary city urban agenda

Suspended sediment transport in the Magdalena River(Colombia,South America):Hydrologic regime,rating parameters and effective discharge variability

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International Journal of Sediment Research 2016年第01期31卷 25-35页

作者： Aldemar Higgins juan Camilo Restrepo juan Carlos Ortiz Jorge Pierini luis Otero (UNS-CIC-CCT)

The Magdalena River has the greatest length（1612 km）and drainage area（257400 km2）of any river system in Colombia,and its watershed occupies 24%of the Colombian *** river originates in the Andean Cordillera at an elevation of 3685 m and flows to its mouth in the Caribbean Sea（Bocas de Cenizas）.For this study,information on daily flow discharge（Q）,suspended sediment transport(Qsand mean suspended sediment concentration（Cs）from 1990-2010 for the Magdalena River,based on measurements at the Caiamar gauging station（the closest station to the mouth）,was provided by the Institute of Hydrology,Meteorology and Environmental Studies of Colombia（IDEAM in Spanish）.The mean annual suspended sediment load was 169±73×10～6tyr-1for the period from 1990-1999 and145±47×10～6 t yr1for the period from 2000-2010,amounting to a 14%reduction in the suspended sediment transport rate between the two *** sediment rating curve（Qs=aQb）was also evaluated for these two periods（1990-1999 and 2000-2010）.An analysis of the regression coefficients（a.b）for the two periods showed a decrease in b and an increase in a after 1999,which coincides with a decrease in suspended sediment *** change might be attributed to natural factors,including the accumulation of sediment in the Depresion Momposina and variation in hydro-climatological patterns in the Caribbean *** in effective transport were confirmed using three methods（log-Normal and Normal distribution,and magnitude-frequency histogram）for the study period.

关键词： Suspended sediment transport Magdalena River Transport regime Effective discharge Sediment rating curve

Protein phosphatases and chromatin modifying complexes in the inflammatory cascade in acute pancreatitis

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World Journal of Gastrointestinal Pharmacology and Therapeutics 2010年第3期1卷 75-80页

作者： Javier Escobar Javier Pereda Alessandro Arduini juan Sastre juan Sandoval luis Aparisi Gerardo lópez-Rodas luis Sabater Department of Physiology University of Valencia 46100 Burjasot (Valencia) Spain Department of Biochemistry & Molecular Biology University of Valencia 46100 Burjasot (Valencia) Spain laboratory of Pancreatic Function University Clinic Hospital 46010 Valencia Spain Department of Surgery University Clinic Hospital 46010 Valencia Spain

Acute pancreatitis is an inflammation of the pancreas that may lead to systemic inflammatory response syndrome and death due to multiple organ failure. Acinar cells, together with leukocytes, trigger the inflammatory cascade in response to local damage of the pancreas. Amplification of the inflammatory cascade requires up-regulation of proinflammatory cytokines and this process is mediated not only by nuclear factor κB but also by chromatinmodifying complexes and chromatin remodeling. Among the different families of histone acetyltransferases, the p300/CBP family seems to be particularly associated with the inflammatory process. cAMP activates gene expression via the cAMP-responsive element (CRE) and the transcription factor CRE-binding protein (CREB). CREB can be phosphorylated and activated by different kinases, such as protein kinase A and MAPK, and then it recruits the histone acetyltransferase co-activator CREB-binding protein (CBP) and its homologue p300. The recruitment of CBP/p300 and changes in the level of histone acetylation are required for transcription activation. Transcriptional repression is also a dynamic and essential mechanism of down-regulation of genes for resolution of inflammation, which seems to be mediated mainly by protein phosphatases (PP1, PP2A and MKP1) and histone deacetylases(HDACs) .Class HDACs are key transcriptional regulators whose activities are controlled via phosphorylationdependent nucleo/cytoplasmic shuttling. PP2A is responsible for dephosphorylation of class HDACs, triggeringnuclear localization and repression of target genes, whereas phosphorylation triggers cytoplasmic localization leading to activation of target genes. The potential benefit from treatment with phosphodiesterase inhibitors and histone deacetylase inhibitors is discussed.

关键词： Dual specificity protein phosphatases Acute pancreatitis Phosphodiesterase inhibitors Cytokines Histone acetylation Pentoxifylline PP2A Serine/threonine protein phosphatases