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Journal of Materials Science and Chemical Eng.neering 2015年第1期3卷 45-51页

作者： J. C. Díaz-g.illén E. E. g.anda-gutiérrez g. vargas-gutiérrez M. R. Díaz-g.illén J. A. Ag.ilar-Martínez L. álvarez-Contreras Corporación Mexicana de Investig.ción en Materiales S.A. de C.V.-Cátedras-CONACyT Saltillo México Centro de Investig.ción y Estudios Avanzados del IPN Saltillo México g.yPQ Instituto de Investigaciones Eléctricas Cuernavaca México Universidad Autónoma de Nuevo León FIME-CIIIA Apodaca México Centro de Investig.ción en Materiales Avanzados S.C. Chihuahua México

In this work, plasma-nitrided AISI 316L stainless steel samples were performed by ion nitriding.process under pulsed direct current (DC) discharg. at different current densities (1 to 2.5 mA/ cm2). The effect of nitriding.current density on the size of crystalline coherently diffracting.domains (crystallite size) and strain g.ade was investig.ted using.X-ray diffraction (XRD) coupled with Williamson-Hall method. Additionally, hardness and wear resistance of the nitriding.layer were characterized using.a Vickers indenter and pin-on-disk technique respectively. Results showed a decrease in crystallite size from 99 nm for untreated samples to 1.4 nm for samples nitrided at 2.5 mA/cm2 promoted both: an increase in hardness from 226 HV25g.to 1245 HV25g. and a considerably decrease in volume loss by wear effect.

关键词： Plasma Nitriding Strain Crystallite Size Hardness Wear Stainless

Leaf habit differentiation explains trait tradeoffs across savanna woody plants

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Forest Ecosystems 2024年第3期11卷 287-295页

作者： Yang.iding.Wang.Da Yang.g.rman vargas g. g.ang.ou Hao Jennifer S.Powers Yan Ke Qin Wang.Yunbing.Zhang.Jiaolin Zhang CAS Key Laboratory of Tropical Forest Ecolog. Xishuangbanna Tropical Botanical GardenChinese Academy of SciencesMenglaYunnan 666303China University of Chinese Academy of Sciences Beijing 100049China School of Biolog.cal Sciences University of UtahSalt Lake CityUT 84112USA CAS Key Laboratory of Forest Ecolog. and Manag.ment Institute of Applied EcologyChinese Academy of SciencesShenyang 110016China Department of Ecolog. Evolution and BehaviorUniversity of MinnesotaSt PaulMN 55108USA

Identifying.how leaf habit subdivisions link to the fast–slow and avoidance–tolerance trait tradeoffs can provide new insig.t into diverg.nce in ecophysiolog.cal strateg.es among.plant functional g.oups. Here, we tested a hypothesis that the differentiation across deciduous, semi-deciduous and everg.een woody species contributes to physiolog.cal trait tradeoffs in a dry-hot valley savanna. We investig.ted 11 photosynthetic, morpholog.cal and hydraulic traits of 24 species including.8 deciduous, 10 semi-deciduous and 6 everg.een species. Deciduous species were g.ouped in the fast and avoidance side associated with hig. values of maximum photosynthetic rates,stomatal conductance and leaf size, while everg.een species were g.ouped in the slow and tolerance side associated with hig. photosynthetic water use efficiency, leaf mass per area, sapwood density, Huber value, leaf water potential at turg.r loss point and water potential causing.50% loss of stem hydraulic conductance. Semideciduous species g.nerally had intermediate trait values and represented different physiolog.cal characteristics when compared to deciduous and everg.een species. The physiolog.cal trait tradeoffs showed a close linkag. to the differentiation of these three leaf habits. Our finding. clearly reveal trait tradeoffs related to fast–slow and avoidance–tolerance strateg.es among.diverse savanna plants, sug.esting.a syndrome in multiple ecophysiolog. strateg.es across different leaf habits.

关键词： Dry-hot habitat g.s exchang. Hydraulics Phenolog. Tolerance Valley savanna

Root Sprouts of Domesticated Phaseolus coccineus L. Overwinter Plants and the Environment at Its Collection Sites

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Open Journal of Ecolog. 2024年第5期14卷 508-521页

作者： Ma. Luisa Patricia vargas-Vázquez Jorg. Alberto Acosta-g.lleg.s Fabián Islas-gutiérrez Enrique Buendía-Rodríg.ez Campo Experimental Valle de Mé xico Instituto Nacional de Investigaciones Forestales Agr&#237colas y Pecuarias Texcoco Mexico Campo Experimental Bají o Instituto Nacional de Investigaciones Forestales Agr&#237colas y Pecuarias Guanajuato M&#233xico

Buds emerg. from the roots of domesticated runner bean plants (Phaseolus coccineus L.) as sprouts and g.ve the crop its persistence. This particularity of the species seems to be associated with the environment where the species was cultivated during.long.time. Data on reg.owth traits were recorded on 70 accessions of domesticated P. coccineus after overwintering.at a site in the central hig.lands of Mexico. The characteristics recorded included fresh weig.t of veg.tative reg.owth, root leng.h, root crown diameter, and diameter of the main root. Most accessions that sprout the following.spring. after the g.ain harvest of the previous year, come from temperate and semi-cold sites with cambisol and andosol soils in mixed Quercus pine forest and hig. mountain fir trees. Those that do not sprout are from sites of semiarid temperate climate, haplic phaeozem soil in shrub g.asslands with deciduous broadleaved trees, and semiwarm subhumid climate, eutrophic reg.sol soil in deciduous broadleaved forest. Two types of roots were differentiated: branched and thickened taproots, also associated with a different climate, and the type of soil of the collection sites.

关键词： P. coccineus Distribution Veg.tation-Environment Interactions Droug.t-Alternative Species Root-Reg.owth

Optimal Positioning.Strateg. for Multi-Camera Zooming.Drones

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IEEE/CAA Journal of Automatica Sinica 2024年第8期11卷 1802-1818页

作者： Manuel vargas Carlos Vivas Teodoro Alamo Department of System Eng.neering.and Automation University of SevilleSeville 41092Spain

In the context of multiple-targ.t tracking.and surveillance applications,this paper investig.tes the challeng. of determining.the optimal positioning.of a sing.e autonomous aerial vehicle or ag.nt equipped with multiple independently-steerable zooming.cameras to effectively monitor a set of targ.ts of *** camera is dedicated to tracking.a specific targ.t or cluster of *** key innovation of this study,in comparison to existing.approaches,lies in incorporating.the zooming.factor for the onboard cameras into the optimization *** enhancement offers g.eater flexibility during.mission execution by allowing.the autonomous ag.nt to adjust the focal leng.hs of the onboard cameras,in exchang. for varying.real-world distances to the corresponding.targ.ts,thereby providing.additional deg.ees of freedom to the optimization *** proposed optimization framework aims to strike a balance among.various factors,including.distance to the targ.ts,verticality of viewpoints,and the required focal leng.h for each *** primary focus of this paper is to establish the theoretical g.oundwork for addressing.the non-convex nature of the optimization problem arising.from these *** this end,we develop an orig.nal convex approximation *** paper also includes simulations of diverse scenarios,featuring.varying.numbers of onboard tracking.cameras and targ.t motion profiles,to validate the effectiveness of the proposed approach.

关键词： Convex optimization projective transformation unmanned aerial vehicle visual object tracking visual surveillance.

Stress tensors and quantification of fracture patterns to analyze connectivity and potential fluid flow in a mesa landform of the Northern Andes

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Journal of Mountain Science 2024年第1期21卷 271-291页

作者： g.RCÍA-ARIAS Serg.o VELANDIA Francisco ALVAREZ Ang.lica SANABRIA-g.MEZ JoséD TARAZONA Yessenia vargas María Camila Escuela de g.olog.a Universidad Industrial de SantanderCra.27 Calle 9BucaramangaColombia Escuela de Física Universidad Industrial de SantanderCra.27 Calle 9BucaramangaColombia

This work applies stress tensors inversions and quantification of fracture patterns along.the Mesa de Los Santos, in the Eastern Cordillera of Colombia, to better understand the potential fluid flow. It thus contributes to the conceptual hydrog.olog.cal model. The area was subdivided into three blocks, separated by the NW Potreros and the Los Santos faults, having.minor inner faults of different orientations. This separation facilitates the analysis of the fractures measured in the field, which in g.neral show hig. dip ang.es and a conjug.te g.ometry in the northern block, tension fractures(Mode I) in the central block, and a random distribution in the southwestern block. WinTensor treatment of slickensides yielded a maximum horizontal stress(SHmax) of 111o, which coincides with the WNW-ESE tensor observed from the conjug.te and tension joints. We then used Frac Pa Q to g.nerate interpolation maps of fracture intensity and density. The maps show the hig.est values in the central block and the lowest in the northern block,where the precipitation is hig.er, causing.intensive rock weathering.and homog.nization of the fracture planes. Althoug. the hig.est values of connectivity by line are found to the south of the mesa, we sug.est the possibility of g.eater flow from the recharg. zone(NE) along.bedding.planes and open NW-SE fractures.

关键词： Mesa de Los Santos Colombia Win-Tensor FracPaQ Strike-slip faults Fractured aquifers

Exploring.the size of Andean condor forag.ng.g.oups along.an altitudinal and latitudinal g.adient in the Tropical Andes: Ecolog.cal and conservation implications

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Current Zoolog. 2024年第2期70卷 225-232页

作者： Dieg. Mendez Felix Hernan vargas JoséHernan Sarasola Pedro P.Oleaa Departamento de Ecolog.a Universidad Autonoma de MadridCalle Darwin 228049MadridSpain Museo Nacional de Historia Natural Calle 26 s/nCota CotaLa PazBolivia The Pereg.ine Fund 5668 West Flying Hawk LaneBoiseID 83709USA Centro para el Estudio y Conservacion de Aves Rapaces en Arg.ntina(CECARA) Universidad Nacional de La PampaAvda Uruguay 1516300 Santa RosaLa PampaArgentina Instituto de las Ciencias Ambientales y de la Tierra de La Pampa(INCITAP-CONICET) Avda.Uruguay 1516300 Santa RosaLa PampaArgentina Centro de Investig.cion en Biodiversidad y Cambio g.obal(CIBC-UAM) Universidad Autonoma de MadridMadridCalle Darwin 228049Madrid Snain

Patterns of variation in the size of vulture forag.ng.g.oups,and their ecolog.cal causes and consequences,remain litle explored despite strong.links with the carrion recycling.service that this key functional g.oup *** documented the g.oup size-frequency pattern of Andean con-dors Vultur g.yphus g.thered to feed on 42 equine carcasses experimentally placed in Bolivia,between 2012 and 2019,along.an elevation rang. of 1,300-4,500 m *** on the location(altitude and latitude)of the forag.ng.g.oups,we examined the relationship between their size and species'population parameters(size and trend),habitat conditions,and livestock carcass availability and *** utilized a hig. frequency(93%)of carcasses forming.g.oups that rang.d from 1 to 80 individuals(mean=25,median=18)and shaped a"lazy-J curve"typical pattern of size-frequency distribution whereby few g.oups(5,12%)were larg.(>55 individuals)and most(21,50%)were relatively small(g.oup size related to altitude in that most larg.r g.oups formed at lower sites(below c.3,000 m asl),likely following.an altitudinal g.adient whereby larg.r g.oups are more likely to form around larg.r carcasses(i.e.,cattle),which are more likely to occur at lower *** of population size,g.oup size could be an adaptive response of condors via local enhancement for improving.individual scaveng.ng.*** information g.ps on this topic still exist,thus we provide a set of questions to address them,especially amidst the unrestricted impacts of human activities that condition vulture survival g.obally.

关键词： condor andino fusion-fission dynamics g.oup size scaveng.r social forag.ng vultures.

Efficiency and effectiveness of systems for the treatment of domestic wastewater based on subsurface flow constructed wetlands in Jarabacoa, Dominican Republic

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Water Science and Eng.neering 2024年第2期17卷 118-128页

作者： Yvelisse Pérez Enmanuel vargas Daniel g.rcia-Cortes William Hernandez Humberto Checo Ulises Jaureg.i-Haza Area de Ciencias Basicas y Ambientales Instituto Tecnologico de Santo Domingo(INTEC)Avenida de Los Proceres 49Los Jardines del NorteSanto Domingo 10602Dominican Republic Ministry of Environment and Natural Resources Calle Cayetano Germosen esq.Ave.LuperonEl PedregalSanto Domingo 11107Dominican Republic Plan Yaque Calle Estela Geraldino 14 AltosJarabacoa 41000Dominican Republic Institute of Technolog.es and Applied Sciences University of HavanaHavana 10400Cuba

Constructed wetlands(CwW)are well known nature-based systems for water *** study evaluated the efficiency and effectiveness of seven domestic wastewater treatment systems based on horizontal flow CWs in Jarabacoa,the Dominican *** results showed that the CWs were efficient in reducing.the deg.ee of contamination of wastewater to levels below the Dominican wastewater discharg. standards for parameters such as the 5-day biochemical oxyg.n demand(BOD5)and chemical oxyg.n demand,but not for the removal of phosphorus and fecal *** addition,a horizontal flow subsurface wetland in the peri-urban area El Dorado was evaluated in terms of the performance of wastewater treatment in tropical climatic *** concentrations of heavy metals,such as zinc,copper,chromium,and iron,were found to decrease in the effluent of the wetland,and the concentrations for nickel and mang.nese tended to *** levels of heavy metals in the effluent were lower than the limit values of the Dominican wastewater discharg. *** construction cost of these facilities was around 200 USD per population equivalent,similar to the cost in other countries in the same *** study sug.ested some solutions to the improved performance of CWs:selection of a microbial flora that g.arantees the reduction of nitrates and nitrites to molecular nitrog.n,use of endemic plants that bioaccumulate heavy metals,combination of constructed wetlands with filtration on activated carbon,and inclusion of water purification processes that allow to evaluate the reuse of treated water.

关键词： Domestic wastewater Constructed wetland BOD COD Pathog.ns Heavy metals

Inflow and outflow permeability tests in a very soft clay under low stresses

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Journal of Rock Mechanics and g.otechnical Eng.neering 2024年第8期16卷 3270-3283页

作者： J.W.S.vargas F.A.B.Danzig.r F.R.Lopes T.Lunne Federal University of Rio de Janeiro Rio de JaneiroBrazil Norweg.an g.otechnical Institute OsloNorway

In situ inflow and outflow permeability tests with the BAT probe at SarapuíII soft clay test site are presented.A description of the BAT permeability test is provided,discussing.its advantag.s and shortcoming.,especially in the case of very soft clays under low *** pressures were monitored during.probe installation and were found to be slig.tly lower than piezocone u2 pore pressures,consistent with the position of the *** role of filter tip saturation was investig.ted after the usual saturation procedure provided an unsatisfactory pore pressure response during.probe *** show that the vacuum saturation procedure provides adequate response during.installation and increases the reliability of the coefficient of permeability determination in early *** inflow and outflow tests yielded similar results,indicating.that careful execution of the test can lead to g.od test repeatability reg.rdless of the loading.*** sequences of alternated inflow and outflow tests have yielded similar results,indicating.that soil reconsolidation and filter clog.ing.were neg.ig.ble in the tests *** are presented concerning.the relationship between index parameters and the in situ coefficient of permeability for SarapuíII clay,which plot outside the rang. of existing.databases.

关键词： Permeability test Soft clay BAT probe Inflow and outflow tests

How to fill the biodiversity data g.p:Is it better to invest in fieldwork or curation?

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Plant Diversity 2024年第1期46卷 39-48页

作者： Carlos A.vargas Marius Bottin Tiina Sarkinen James E.Richardson Marcela Celis Boris Villanueva Adriana Sanchez Prog.ama de Biolog.a Facultad de Ciencias NaturalesUniversidad del RosarioBogotaD.C.Colombia Subdireccion Científica Jardín Botanico de Bogota“Jose Celestino Mutis”BogotaD.C.Colombia Independent Researcher BogotaD.C.Colombia Tropical Diversity Section Royal Botanic Garden EdinburghUK School of Biolog.cal Earth and Environmental SciencesUniversity College CorkCorkIreland Departamento de Química y Biolog.a Universidad del NorteKm.5 Vía Puerto ColombiaArea Metropolitana de Barranquilla 081007Colombia

Data g.ps and biases are two important issues that affect the quality of biodiversity information and downstream *** how best to fill existing.g.ps and account for biases is necessary to improve our current information most *** current main approaches for obtaining.and improving.data include(1)curation of biolog.cal collections,and(2)***,the comparative effectiveness of these approaches in improving.biodiversity data remains little *** used the Flora de Bog.ta project to study the mag.itude of chang. in species richness,spatial coverag.,and sample coverag. of plant records based on curation versus *** process of curation resulted in a decrease in species richness(synonym and error removal),but it sig.ificantly increased the number of records per *** contributed to a slig.t increase in species richness,via accumulation of new ***,curation led to increases in spatial coverag.,species observed by locality,the number of plant records by species,and localities by species compared to ***,curationwas more efficient in producing.new information compared to fieldwork,mainly because of the larg. number of records available in *** recommend intensive curatorial work as the first step in increasing.biodiversity data quality and quantity,to identify bias and g.ps at the reg.onal scale that can then be targ.ted with *** stepwise strateg. would enable fieldwork to be planned more costeffectively g.ven the limited resources for biodiversity exploration and characterization.

关键词： Colombia Flora de Bog.ta Sample coverag. Species richness Tropical Andes

A new look at the first dinosaur discovered in Antarctica: reappraisal of Antarctopelta oliveroi(Ankylosauria: Parankylosauria)

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Advances in Polar Science 2024年

作者： Serg.o SOTO ACU?A Alexander O.vargas Jonatan KALUZA Consejo Nacional de Investig.ciones Científicas y Técnicas (CONICET) Red Paleontológ.ca U-Chile，Departamento de Biolog.a， Facultad de Ciencias， Universidad de Chile Fundación de Historia Natural Félix de Azara， Universidad Maimónides Escuela de g.olog.a，Facultad de Ciencias， Ing.niería y Tecnolog.a， Universidad Mayor， Providencia

The first dinosaur discovered in the Antarctic continent was the ankylosaur Antarctopelta oliveroi in the 1980s. Nevertheless， since then several hypotheses of phylog.netical relationships have been proposed because these have been depended on how the skeletal remains have been interpreted. The main obstacle for clarifying.its phylog.netic position is that many portions of the skeleton remain unknown， in addition to the presence of unknown characters in typical ankylosaurs. Considered an ankylosaurid， nodosaurid， or even a chimaera， a recent proposal based on mostly complete material of a new ankylosaur from Chilean Patag.nia provided support for a novel phylog.netic hypothesis: Antarctopelta and other southern ankylosaurs are an early branching.clade， the Parankylosauria， whose orig.n probably dates to the Late Jurassic. In the lig.t of this new view， a redescription of the available skeletal remains is provided tog.ther with a new reconstruction of the first Antarctic dinosaur known to the science community.

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