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Glacier reconstruction of La Covacha Massif in Sierra de Gredos(central Spain) during the Last Glacial Maximum

Journal of Mountain Science 2019年第6期16卷 1336-1352页

作者： néstor campos David PALACIOS Luis M.TAnARRO Department of Geography Complutense University of Madrid

A paleoglacier reconstruction during the Last Glacial Maximum(LGM) is presented for a high mountain area of La Covacha massif in Sierra de Gredos(Iberian Central System) in central Spain. The moraines that, according with the previous literature, had formed during the global LGM, were mapped through photo interpretation of digital aerial photographs and 3D images and detailed field surveys. The topography of the paleoglaciers was estimated using a simple steady-state model that assumed a perfectly plastic ice rheology, reconstructing the theoretical ice profiles and obtaining the ice thickness of the glaciers during the LGM. The reconstruction of the glaciers was carried out using automated and semi-automated physically-based models, obtaining more realistic results with semi-automated models. According to our study, the paleoglaciers in the study area covered an area of 34.79 km^2 during the global LGM, with a maximum ice thickness of 366 meters in La Vega gorge, a total volume of 34.25 × 108 m^3 and a mean paleoELA of 1932 meters. Most of the ice(~82%) was in paleoglaciers facing north, and the rest was in paleoglaciers with other orientations. This emphasizes the importance of orientation in relation to glacier dynamics and ice accumulation. The results obtained in the calculation of paleoELAs during the global LGM in Gredos are average compared to the Iberian mountains of the northwest where the values were much lower, and with respect to those of the Southwest, much higher. This demonstrates the importance of the exposure of Mediterranean mountains to the humidity sources coming from the nW during the global LGM, as is the case at present.

关键词： Glacier reconstruction Paleoglacier Ice thickness Equilibrium line altitude Iberian Central System

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The Influence of Climate Variability on Holoplanktonic Polychaetes Populations of Ocean Sector of the Colombian Pacific Basin

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Open Journal of Ecology 2021年第4期11卷 317-343页

作者： José Manuel Gutiérrez-Salcedo Adibe Cárdenas-Oliva néstor H. campos Marine Fauna of Colombia Biodiversity and Uses Research Group Universidad Nacional de Colombia Caribbean Headquarters Santa Marta Colombia Museo de Historia natural Marina de Colombia—MHnMC (Makuriwa) Instituto de Investigaciones Marinas y Costeras—INVEMAR Santa Marta Colombia Instituto de Estudios en Ciencias del Mar—CECIMAR. Universidad nacional de Colombia Caribbean Headquarters Santa Marta Colombia

Studies of holoplanktonic polychaetes in the Tropical Eastern Pacific have focused on their systematics and distribution however, population responses related to climate variability are non-existent. Therefore, the present work described for the first time the influence of the climatic variability 2004-2012 on the holoplanktonic polychaetes populations, as well as their relationship to environmental variables. Species of the Alciopidae, Lopadorrhynchidae and Iospilidae families were identified from 85 samples collected in the Pacific Basin of Colombia, contrasting them with the presence of EnSO, and correlating them with the environmental variables of temperature, salinity and chlorophyll-α concentration. Of the 14 species identified, only Lopadorrhynchus cf. henseni and L. cf. brevis increased their densities under El niñn>o and correlated positively with temperature. Rhynchonereella cf. petersii correlated negatively with temperature;while R. cf. gracilis and Pelagobia cf. longicirrata were positively correlated with chlorophyll-α concentration and salinity, respectively. Additionally, with the first description of the environmental ranges of the 14 species identified for the Colombian Pacific basin, it was found that the most commons species presented broader environmental ranges. The results from the current research are consistent with previous studies in other regions of the Pacific and latitudes. The responses of the organisms suggest trophic and mobility trends that were not known for tropical holoplanktonic polychaete species.

关键词： Temperature Chlorophyll Oceanic Province Tropical Region El niño Southern Oscillation—EnOS

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The pitfalls in electrocatalytic nitrogen reduction for ammonia synthesis

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Journal of Energy Chemistry 2021年第10期30卷 149-154,I0005页

作者： Huimin Liu néstor Guijarro Jingshan Luo Institute of Photoelectronic Thin Film Devices and Technology Solar Energy Research CenterKey Laboratory of Photoelectronic Thin Film Devices and Technology of TianjinMinistry of Education Engineering Research Center of Thin Film Photoelectronic TechnologyRenewable Energy Conversion and Storage CenterNankai UniversityTianjin 300350China Institute of Electrochemistry University of AlicanteAlicante E-03080Spain

Ammonia synthesis by electrocatalytic nitrogen reduction reaction(EC-nRR)has gained momentum in recent years fueled by its potential to operate at ambient conditions,unlike the highly energyintensive yet long-standing Haber-Bosch ***,the large disparity of the yields and Faradic efficiencies reported for EC-nRR raises serious concerns about the reliability of the experimental *** this perspective,we elaborate on the potential sources of error when assessing EC-nRR and update the testing protocols to circumvent them,and more importantly,we pose a general call for consensus on ammonia production analysis and reporting to lay the solid foundations that this burgeoning field requires to thrive.

关键词： Electrocatalytic nitrogen reduction Ammonia synthesis Pitfalls Standard protocols

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Sol–gel La2O3–ZrO2 mixed oxide catalysts for biodiesel production

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Journal of Energy Chemistry 2018年第2期27卷 565-572页

作者： Daniela Salinas Catherine Sepúlveda néstor Escalona J.L.GFierro Gina Pecchi Departamento de Fisicoquimica. Facultad de Ciencias Quimicas Universidad de Concepcion Post Office 160-C Concepcion Chile Departamento de Quimica Facultad de Ciencias Universidad del Biobio Post Office 5-C Concepcion Chile Departamento Ingenieria Quimica y Bioprocesos Escuela de lngenieria Pontificia Universidad Catolica de Chile Avda. Vicuria Mackenna 4870 Maeul Santiago 7820436 Chile Centro de Investigacion en nanotecnolagia y Materiales Avanzados (CIEn-UC) Pontificia Universidad Catolica de Chile Post Office 306 Santiago Chile Departamento de Quimica Fisica Facultad de Quimica Pontificia Universidad Catolica de Chile Post Offce 306 Santiago Chile Instituto de Catalisis y Petroleoquimica CSIC 28049 Madrid. Espana

Different La2O3 contents（0, 1, 2, 3, and 5 wt%） were used to prepared La2O3-ZrO2 mixed oxides calcined at 600 ℃ by the sol-gel method. The catalytic activity was measured as biodiesel production from canola oil through a transesterification reaction. The characterization results indicate that the La2O3 monolayer formation and extent of basicity of m-ZrO2 have a large influence on biodiesel *** biodiesel conversion（56% at 4 h） was obtained with the 3% La2O3-ZrO2 catalyst in the presence of basic sites and the formation of a monolayer of La2O3. The decrease in the catalytic activity for 5% La2O3-ZrO2 resulted from the loss of active sites on the catalyst because of agglomeration, which was suggested by XPS and the isoelectric point. The kinetic data fit to a pseudo-first order constant, and the largest kinetic constant corresponds to 3% La2O3-ZrO2, currently the largest heterogeneous non-alkaline metal catalyst reported for a transesterification reaction.

关键词： La2O3 -ZrO2 Sol-gel Biodiesel Canola oil Transesterification

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Relict glacial landscape in the Sierra Baguales Mountain Range(50°-51°S):evidence of glaciation dynamics and types in the eastern foothills of the southern Patagonian Andes

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Journal of Mountain Science 2017年第2期14卷 282-295页

作者： ARAOS.JoséMiguel LE ROUX.Jacobus Philiphus GUTIERREZ.néstor Mauricio Department of Geology FCFMUniversidad de ChilePlaza Ercilla#803SantiagoChile Department of Geography Faculty of Social Sciences.Universidad Alberto HurtadoUienfuegos#41SantiagoChile Department of Geology FCFMUniversidad de Chile.Andean Geothermal Centre of ExcellencePlaza Ereilla#803SantiagoChile

The glacial morphology of southern South American presents invaluable evidence to reconstruct former glacier behaviour and its relation to climate and environmental changes. However, there are still spatial and temporal gaps in the reconstruction of the Holocene Patagonian glacial landscape. Here we present the first geomorphological record for the Sierra Baguales Mountain Range(SBMR), forming the eastern foothills of the Southern Patagonian Andes 200 km from the Pacific coast. This area is topographically isolated from the Southern Patagonian Ice Field(SPIF), and is affected by the Westerly Winds. The study area shows evidence of ice sheet and alpine glaciations related to Andean uplift,which caused a marked climatic contrast between its western and eastern flanks since the Last Glacial Maximum(LGM). The regional rock mass strength and precipitation gradient acted as a controlling factor in the glacial cirque distribution and sizes, as well as in the development of glaciation types. We report new radiocarbon dates associated with warm/dry to cold/wet climatic changes during the middle Holocene, when former small alpine glaciers were located in the uppermost section of the SBMR basins, and eventually converged to form a small ice field or a composite valley glacier at lower *** can be explained by an estimated regional temperature drop of 3.8°C±0.8°C, based on a 585±26m Equilibrium Line Altitude(ELA) descent, inferred by geomorphological evidence and the Accumulation Area Ratio(AAR), in addition to a free-air adiabatic lapse rate. Subsequently, the glaciers receded due to climatic factors including a rise in temperature, as well as non-climatic factors, mainly the glacier bedrock topography.

关键词： Glacial morphology Sierra Baguales Ice sheet glaciations Alpine glaciations Middle Holocene

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Analysis of Operating Variables in the Catalytic Purification of Butene-1 in a Trickle Bed

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Chinese Journal of Chemical Engineering 1998年第2期6卷 13-25页

作者： Sergio P.Bressa néstor O.Ardiaca Osvaldo M.Martinez Guillermo F.Barreto Depto.de Ing.Qca. Fac.de Ing.U.N.L.P.l esq.47(1900)La Plata-Argentina Centro de Investigacion y Dcysarrollo en Procesos Cataliticos(CINDECA)Calle 47 N°257CC59(1900)Plata-ArgentinaDepto.de Ing.Qca.Fac.de Ing.U.N.L.P.l esq.47(1900)La Plata-Argentina Centro de Investigacion y Dcysarrollo en Procesos Cataliticos(CINDECA)Calle 47 N°257CC59(1900)Plata-ArgentinaDepto.de Ing.Qca.Fac.de Ing.U.N.L.P.l esq.47(1900)La Plata-Argentina Centro de Investigacion y Dcysarrollo en Procesos Cataliticos(CINDECA)Calle 47 N°257CC59(1900)Plata-ArgentinaDepto.de Ing.Qca.Fac.de Ing.U.N.L.P.l esq.47(1900)La Plata-Argentina Centro de Investigacion y Dcysarrollo en Procesos Cataliticos(CINDECA)Calle 47 N°257CC59(1900)Plata-Argentina

A mathematical model for analyzing and simulating selective hydrogenation of butyne-1 and 1,3-bu-tadiene in industrial trickle bed reactors operated to obtain high purity butene-1 is presented in this *** analysis of typical operating conditions,only the relevant phenomena are finally retained in the model *** model is then employed to analyze the effect of operating variables and catalyst selectivity in *** particular,the search for the minimum hydrogen flow rate necessary to fulfil butene-1 purityspecifications is undertaken.

关键词： selective hydrogenation butene-1 1 3-butadiene trickle bed reactor

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A Value for Games Defined on Graphs

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Applied Mathematics 2024年第5期15卷 331-348页

作者： néstor Bravo Departamento de Matemá ticas Universidad de Guanajuato Guanajuato Mexico

Given a graph g=( V,A ) , we define a space of subgraphs M with the binary operation of union and the unique decomposition property into blocks. This space allows us to discuss a notion of minimal subgraphs (minimal coalitions) that are of interest for the game. Additionally, a partition of the game is defined in terms of the gain of each block, and subsequently, a solution to the game is defined based on distributing to each player (node and edge) present in each block a payment proportional to their contribution to the coalition.

关键词： Graph Theory Values for Graphs Cooperation Games Potential Function

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China's Solution to Global Governance Crisis

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Contemporary World 2022年第3期 35-38页

作者： néstor Restivo Working Group on China at Argentine Council for International Relations

In today’s highly globalized world, countries and regions are ever more closely intertwined with more complex relations. As COVID-19 pandemic changes international order in a profound way, the challenges facing global governance system have intensified. There is an urgent call for change. In this context, China offers a new solution to improving global governance by proposing the vision of building a community with a shared future for mankind.

关键词： intensified today profound

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Monitoring hepatitis C virus treatment rates in an Opioid Treatment Program:A longitudinal study

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World Journal of Gastroenterology 2020年第38期26卷 5874-5883页

作者： Arantza Sanvisens Inmaculada Rivas Eva Faure néstor Espinach Anna Hernandez-Rubio Xavier Majó Joan Colom Robert Muga Department of Internal Medicine Hospital Universitari Germans Trias i PujolBadalona 08916Spain Mental Health and Addiction Service Badalona Serveis Assistencials-BSABadalona 08911Spain Department of Internal Medicine Hospital Universitari Germans Trias i PujolUniversitat Autònoma de BarcelonaBadalona 08916Spain Program on HIV STIs and Viral Hepatitis-PCAVIHV Public Health Agency of CataloniaGeneralitat de CatalunyaBarcelona 08005Spain

BACKGROUnD Direct-acting antivirals(DAAs)are recommended for the treatment of hepatitis C virus(HCV)infection in patients treated with methadone or *** To assess HCV treatment rates in an Opioid Treatment Program(OTP).METHODS This longitudinal study included 501 patients(81.4%men,median age:45 years;interquartile range:39-50 years)enrolled in an OTP between October 2015 and September *** were followed until September *** on sociodemographics,substance use,HCV infection,human immunodeficiency virus(HIV)infection and laboratory parameters were collected at *** analyzed medical records to evaluate HCV ***-Meier methods and Cox regression models were used to analyze the DAA treatment uptake and to identify treatment *** Prevalence of HCV and HIV infection was 70%and 34%,*** anti-HCV-positive(n=336)patients,47.2%,41.3%,and 31.9%used alcohol,cannabis,and cocaine,***-RnA tests were positive in 233(69.3%)*** patients(8.3%)cleared the infection,and 59/308(19.1%)had received interferon-based treatment regimens before *** 249 patients eligible,111(44.6%)received *** rates significantly increased over time from 7.8/100 person-years(p-y)(95%CI:5.0-12.3)in 2015 to 18.9/100 p-y(95%CI:11.7-30.3)in *** a multivariate analysis,patients with HIV co-infection were twice as likely to receive DAAs(HR=1.94,95%CI:1.21-3.12)than patients with HCV *** drug use was an independent risk factor for not receiving treatment against infection(HR=0.48,95%CI:0.29-0.80).COnCLUSIOn HCV treatment is evolving in patients with HCV-HIV *** drug use while in an OTP might negatively impact the readiness to treat infection.

关键词： Direct-acting antiviral agents Opioid Treatment Program Opioid agonist therapy Hepatitis C virus infection Human immunodeficiency virus infection Drug use

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Plant cover as an estimator of above-ground biomass in semi-arid woody vegetation in northeast Patagonia,Argentina

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Journal of Arid Land 2021年第9期13卷 918-933页

作者： Laura B RODRIGUEZ Silvia S TORRES ROBLES Marcelo F ARTURI Juan M ZEBERIO Andrés C H GRAnD néstor I GASPARRI national University of Río negro Atlantic HeadquartersCenter for Environmental Studies from Norpatagonia(CEANPa)Viedma 8500Argentina national Council of Scientific and Technical Research(COnICET) Viedma 8500Argentina Ecological and Environmental Systems Research Laboratory(LISEA) National University of La PlataLa Plata 1900Argentina national Institute of Agricultural Technology(InTA) AER PatagonesCarmen de Patagones 8504Argentina Institute of Regional Ecology(IER) National University of Tucumán(UNT)-National Council of Scientific and Technical Research(CONICET)Tucumán 4000Argentina Faculty of natural Sciences and Miguel Lillo Institute National University of Tucumán(UNT)Yerba Buena 4107Argentina

The quantification of carbon storage in vegetation biomass is a crucial factor in the estimation and mitigation of CO2 ***,arid and semi-arid regions are considered an important carbon ***,they have received limited attention and,therefore,it should be a priority to develop tools to quantify biomass at the local and regional *** plant variables,such as stem diameter and crown area,were reported to be good predictors of individual plant ***-level variables,such as plant cover and mean height,are also easy-to-measure estimators of above-ground biomass(AGB)in dry *** this study,we estimated the AGB in semi-arid woody vegetation in northeast Patagonia,*** evaluated whether the AGB at the stand level can be estimated based on plant cover and to what extent the estimation accuracy can be improved by the inclusion of other field-measured structure *** also evaluated whether remote sensing technologies can be used to reliably estimate and map the regional mean *** this purpose,we analyzed the relationships between field-measured woody vegetation structure variables and AGB as well as LAnDSAT TM-derived *** obtained a model-based ratio estimate of regional mean AGB and its standard *** plant cover allowed us to obtain a reliable estimation of local AGB,and no better fit was attained by the inclusion of other structure *** stand-level plant cover ranged between 18.7%and 95.2%and AGB between about 2.0 and 70.8 Mg/hm^(2).AGB based on total plant cover was well estimated from LAnDSAT TM bands 2 and 3,which facilitated a model-based ratio estimate of the regional mean AGB(approximately 12.0 Mg/hm^(2))and its sampling error(about 30.0%).The mean AGB of woody vegetation can greatly contribute to carbon storage in semi-arid ***,plant cover estimation by remote sensing images could be used to obtain regional estimates and map biomass,as well as to assess and monitor the i

关键词： above-ground biomass shrublands ratio estimation carbon storage remote sensing Patagonia

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