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Mercury in an ultraoligotrophic North Patagonian Andean lake (Argentina): Concentration patterns in different components of the water column

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Journal of Environmental Sciences 2010年第8期22卷 1171-1178页

作者： María Arribére María C Diéguez sergio ribeiro guevara Claudia P Queimalios Vesna Fajon Mariana Reissig Milena Horvat LAAN-CNEA CAB Av. Bustillo Km 9.5 8400 Bariloche Argentina Laboratorio de Fotobiología INIBIOMA (Universidad Nacional del Comahue-CONICET) Department of Environmental Sciences Jozef Stefan Institute

The deep, ultraoligotrophic piedmont lakes of Northern Patagonia （Argentina） are located in pristine and barely impacted areas, along a wide latitudinal range. Several studies have reported moderate to high total mercury （Hg） concentrations and contrasting methylmercury （CH3Hg＋） production in different lake compartments. Sources of Hg for western Patagonian terrestrial and aquatic ecosystems are still not clear; while point sources can be ruled out and atmospheric deposition is a plausible source, along with contribution from active volcanic areas of the Andes. In this investigation, we reported a noticeably seasonal, spatial （between lake branches）, and vertical （between water column strata） heterogeneity in the total Hg concentrations found in the pelagic zone of Lake Moreno. Sterile water samples taken in a depth profile of the lake showed moderate to high concentrations of CH3Hg＋ in autumn with a decreasing trend with depth. Our results indicated that Hg is largely allocated in the plankton fraction between 10–53 μm; which dominated within the euphotic （epilimnetic） zone of the lake due to the high densities attained by two species of the dinoflagellate Gymnodinium. The 53–200 μm planktonic size fraction （comprising rotifers, ciliates and immature stages of crustaceans） and the 200 μm fraction （calanoid copepods and cladocerans） were found to bear strikingly lower total Hg concentrations, suggesting that the magnification of Hg at the planktonic consumer level is negligible.

关键词： Patagonia deep lakes total mercury plankton

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Influence of dissolved organic matter character on mercury incorporation by planktonic organisms: An experimental study using oligotrophic water from Patagonian lakes

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Journal of Environmental Sciences 2013年第10期25卷 1980-1991页

作者： María C.Diéguez Claudia P.Queimalios sergio ribeiro guevara Mark Marvin-DiPasquale Carolina Soto Crdenas María A.Arribre Laboratorio de Fotobiología INIBIOMA CONICET-UNComahue Laboratorio de Fotobiolog INIBIOMA CONICET-UNComahue Laboratorio de Anlisis por Activación Neutrónica Centro Atómico Bariloche CNEA United States Geological Survey Laboratorio de Anlisis por Activacio Neutrónica Centro Atómico Bariloche CNEA

Ligands present in dissolved organic matter （DOM） form complexes with inorganic divalent mercury （Hg^2＋） affecting its bioavailability in pelagic food webs. This investigation addresses the influence of a natural gradient of DOM present in Patagonian lakes on the bioaccumulation of Hg^2＋（the prevailing mercury species in the water column of these lakes） by the algae Cryptomonas erosa and the zooplankters Brachionus calyciflorus and Boeckella antiqua. Hg^2＋ accumulation was studied through laboratory experiments using natural water of four oligotrophic Patagonian lakes amended with^197Hg^2＋. The bioavailability of Hg^2＋ was affected by the concentration and character of DOM. The entrance of Hg^2＋ into pelagic food webs occurs mostly through passive and active accumulation. The incorporation of Hg^2＋ by Cryptomonas, up to 27% of the Hg^2＋ amended, was found to be rapid and dominated by passive adsorption, and was greatest when low molecular weight compounds with protein-like or small phenolic signatures prevailed in the DOM. Conversely, high molecular weight compounds with a humic or fulvic signature kept Hg^2＋ in the dissolved phase, resulting in the lowest Hg^2＋ accumulation in this algae. In Brachionus and Boeckella the direct incorporation of Hg from the aqueous phase was up to 3% of the Hg^2＋ amended. The dietary incorporation of Hg^2＋ by Boeckella exceeded the direct absorption of this metal in natural water, and was remarkably similar to the Hg^2＋ adsorbed in their prey. Overall, DOM concentration and character affected the adsorption of Hg^2＋ by algae through competitive binding, while the incorporation of Hg^2＋ into the zooplankton was dominated by trophic or dietary transfer.

关键词： mercury dissolved organic matter plankton mercury incorporation Patagonian lakes Argentina

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海外大型露天矿山智能化建设体系与应用实践——以拉斯邦巴斯铜矿为例

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金属矿山 2025年第1期 207-215页

作者：吴立活 Miguel Canz Hermes guevara 李国清侯杰张永芳拉斯邦巴斯铜矿秘鲁利马15001 五矿资源有限公司中国香港999000 北京科技大学土木与资源工程学院北京100083

拉斯邦巴斯铜矿运用现代化信息技术构建覆盖“地质资源—计划管理—过程控制—安全保障—智能决策”全方位智能化建设框架,通过关键应用场景设计与应用,实现矿山生产运营的高效协同与智能管理。针对矿体赋存条件复杂、开采规模庞大、作... 详细信息

拉斯邦巴斯铜矿运用现代化信息技术构建覆盖“地质资源—计划管理—过程控制—安全保障—智能决策”全方位智能化建设框架,通过关键应用场景设计与应用,实现矿山生产运营的高效协同与智能管理。针对矿体赋存条件复杂、开采规模庞大、作业地点分散等问题,应用矿床地质建模、三维可视化及无人机技术,实现矿山全生命周期的地质资源精细化管控。在此基础上优化开采工艺,应用精准定位及智能卡调技术,实现大规模高陡边坡的精准穿孔、控制爆破以及矿岩运输。构建了以超前预防为目标,全面覆盖人、机、环、管,与生产过程深度融合的矿山安全监测预警体系,显著提升了矿山的安全作业水平。通过云平台和数据湖技术实现多源异构数据融合,应用机器学习算法构建数据分析与决策模型,为矿山管理者科学决策提供有力支持。拉斯邦巴斯铜矿智能化建设成果对于国内大型露天矿山智能化建设具有一定的示范作用。

关键词：海外矿产资源大型露天矿拉斯邦巴斯铜矿智能矿山应用场景

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Planar matrices and arrays of Feynman diagrams:poles for higher k

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Communications in Theoretical Physics 2024年第4期76卷 1-13页

作者： Alfredo guevara Yong Zhang Perimeter Institute for Theoretical Physics WaterlooON N2L 2Y5Canada Department of Physics&Astronomy University of WaterlooWaterlooON N2L 3G1Canada Society of Fellows Harvard UniversityCambridgeMA 02138United States of America CAS Key Laboratory of Theoretical Physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China School of Physical Sciences University of Chinese Academy of SciencesNo.19A Yuquan RoadBejing 100049China

Planar arrays of tree diagrams were introduced as a generalization of Feynman diagrams that enable the computation of biadjoint amplitudes m_(n)(^(k))for k>*** this follow-up work,we investigate the poles of m_(n)(^(k))from the perspective of such *** general k,we characterize the underlying polytope as a Flag Complex and propose a computation of the amplitude-based solely on the knowledge of the poles,whose number is drastically less than the number of the full *** an example,we first provide all the poles for the cases(k,n)=(3,7),(3,8),(3,9),(3,10),(4,8)and(4,9)in terms of their planar arrays of degenerate Feynman *** then implement simple compatibility criteria together with an addition operation between arrays and recover the full collections/arrays for such *** the way,we implement hard and soft kinematical limits,which provide a map between the poles in kinematic space and their combinatoric *** use the operation to give a proof of a previously conjectured combinatorial duality for arrays in(k,n)and(n-k,n).We also outline the relation to boundary maps of the hypersimplex Δ_(k,n) and rays in the tropical Grassmannian Tr(k,n).

关键词： Feynman diagrams biadjoint amplitudes poles

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Potential distribution of a montane rodent (Cricetidae, Handleyomys chapmani) through time in Mexico: the importance of occurrence data

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Journal of Mountain Science 2021年第8期18卷 2024-2033页

作者： CANO Ivonne guevara Lazaro Department of Zoology Institute of BiologyNational Autonomous University of Mexico04510Mexico CityMexico

Ecological Niche Modeling uses the geographic coordinates of species presence records as the primary input to estimate potential geographic *** is little known whether carrying out rigorous data pre-processing is necessary before building niche models to be transferred to different time *** we compared the current,past,and future potential distributions projected by niche models built from two different databases,an open-access database and a database compiled ad hoc,for Handleyomys chapmani,a rodent closely associated with montane cloud forests in *** models predicted different spatial patterns of climatic suitability for the three periods *** on our current knowledge of cloud forest species in Mexico,the distributions predicted by the model built from the ad hoc database are more ecologically realistic than those obtained from the open-access *** models built using the open-access database were particularly inaccurate at the limits of the geographic range,predicting larger,more diffuse distributions for the three *** conclude that pre-processing occurrence data is crucial for mountain species,as the number of localities and even minor inaccuracies in the geographic coordinates can translate into very different climatic conditions due to abrupt altitudinal ***,the predicted shifts in the potential distribution of *** over time indicate that this species is highly susceptible to climate change.

关键词： Cloud forests Ecological Niche Modeling Handleyomys chapmani Maxent Rodentia

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Standardizing and Centralizing Datasets for Efficient Training of Agricultural Deep Learning Models

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Plant Phenomics 2023年第4期5卷 689-702页

作者： Amogh Joshi Dario guevara Mason Earles Department of Viticulture and Enology University of CaliforniaDavisDavisCAUSA Department of Biological and Agricultural Engineering University of CaliforniaDavisDavisCAUSA AI Institute for Next-Generation Food Systems(AIFS) University of CaliforniaDavisDavisCAUSA

In recent years,deep learning models have become the standard for agricultural computer *** models are typically fine-tuned to agricultural tasks using model weights that were originally fit to more general,non-agricultural *** lack of agriculture-specific fine-tuning potentially increases training time and resource use,and decreases model performance,leading to an overall decrease in data *** overcome this limitation,we collect a wide range of existing public datasets for 3 distinct tasks,standardize them,and construct standard training and evaluation pipelines,providing us with a set of benchmarks and pretrained *** then conduct a number of experiments using methods that are commonly used in deep learning tasks but unexplored in their domain-specific applications for *** experiments guide us in developing a number of approaches to improve data efficiency when training agricultural deep learning models,without large-scale modifications to existing *** results demonstrate that even slight training modifications,such as using agricultural pretrained model weights,or adopting specific spatial augmentations into data processing pipelines,can considerably boost model performance and result in shorter convergence time,saving training ***,we find that even models trained on low-quality annotations can produce comparable levels of performance to their high-quality equivalents,suggesting that datasets with poor annotations can still be used for training,expanding the pool of currently available *** methods are broadly applicable throughout agricultural deep learning and present high potential for substantial data efficiency improvements.

关键词： weights overcome shorter

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Bats and their vital ecosystem services:a global review

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Integrative Zoology 2022年第1期17卷 2-23页

作者： Leidy Azucena RAMÍREZ-FRÁNCEL Leidy Viviana GARCÍA-HERRERA sergio LOSADA-PRADO Gladys REINOSO-FLÓREZ Alfonso SÁNCHEZ-HERNÁNDEZ sergio ESTRADA-VILLEGAS Burton KLIM Giovany guevara Programa de Doctorado en Ciencias Biológicas&Grupo de Investigación en Zoología(GIZ) Facultad de CienciasUniversidad del TolimaIbaguéColombia Programa para la Conservación de los Murciélagos de Colombia BogotáD.C.Colombia Departamento de Biología&Grupo de Investigación en Zoología(GIZ) Facultad de CienciasUniversidad del TolimaIbaguéColombia Departamento de Matemáticas y Estadística Facultad de CienciasUniversidad del TolimaIbaguéColombia Yale School of the Environment Yale UniversityNew HavenConnecticutUSA Smithsonian Tropical Research Institute BalboaRepublic of Panama Department of Natural History Royal Ontario MuseumTorontoOntarioCanada

Bats play crucial ecosystem services as seed dispersers,pollinators,controllers of insects,and nutrient ***,there has not been a thorough global review evaluating these roles in bats across all biogeographical regions of the *** reviewed the literature published during the last two decades and identified 283 relevant studies:78 dealt with the control of potential insect pests by bats,80 related to the suppression of other arthropods,60 on the dispersal of native or endemic seeds,11 dealt with the dispersal of seeds of introduced plants,29 on the pollination of native or endemic plants,1 study on pollination of introduced plants,and 24 on the use of guano as *** literature search showed that queries combining the terms“seed dispersal,”“insectivorous bats,”“nectarivorous bats,”“use of guano,”and“ecosystem services”returned 577 studies,but half were experimental in *** found that the evaluation of ecosystem services by bats has been mostly conducted in the Neotropical and Palearctic *** detect differences across relevant studies,and to explain trends in the study of ecosystem services provided by bats,we performed generalized linear mixed models(GLMM)fitted with a Poisson distribution to analyze potential differences among sampling *** identified 409 bat species that provide ecosystem services,752 insect species consumed by bats and 549 plant species either dispersed or pollinated by *** review summarizes the importance of conserving bat populations and the ecological services they provide,which is especially important during the current pandemic.

关键词： chiroptera ecosystem services frugivory,guano,insectivory nectarivory pest control pollination seed dispersal

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Glial-derived transforming growth factor β1(TGF-β1):a key factor in multiple sclerosis neuroinflammation

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Neural Regeneration Research 2021年第3期16卷 510-511页

作者： Coram guevara Fernando C.Ortiz Mechanisms of Myelin Formation and Repair Laboratory Instituto de Ciencias BiomédicasFacultad de Ciencias de la SaludUniversidad Autónoma de ChileSantiagoChile

Glial cell activation and neuroinflammation in multiple sclerosis(MS):MS is an irreversible and progressive central nervous system(CNS)disease which originates in the autoimmune attack of lymphocytes against CNS *** specialized membrane,synthesized by oligodendrocytes(OL)in the CNS,provides metabolic support to axons and allows for saltatory conduction in *** lack of myelin(i.e.,demyelination)leads to axonal degeneration,neuronal death,and the consequent neurological disabilities(Franklin and Ffrench-Constant,2017).

关键词： inflammation degeneration sclerosis

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Planar matrices and arrays of Feynman diagrams

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Communications in Theoretical Physics 2024年第3期76卷 15-32页

作者： Freddy Cachazo Alfredo guevara Bruno Umbert Yong Zhang Perimeter Institute for Theoretical Physics WaterlooON N2L 2Y5Canada Department of Physics and Astronomy University of WaterlooWaterlooON N2L 3G1Canada CECs Valdivia y Departamento de Física Universidad de ConcepciónCasilla 160-CConcepciónChile Center for the Fundamental Laws of Nature Society of Fellows and Black Hole InitiativeHarvard UniversityCambridgeMA 02138United States of America Department of Applied Mathematics Western UniversityLondonON N6A 5B7Canada CAS Key Laboratory of Theoretical Physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China School of Physical Sciences University of Chinese Academy of SciencesNo.19A Yuquan RoadBeijing 100049China

Recently,planar collections of Feynman diagrams were proposed by Borges and one of the authors as the natural generalization of Feynman diagrams for the computation of k=3 biadjoint *** collections are one-dimensional arrays of metric trees satisfying an induced planarity and compatibility *** this work,we introduce planar matrices of Feynman diagrams as the objects that compute k=4 biadjoint *** are symmetric matrices of metric trees satisfying compatibility *** introduce two notions of combinatorial bootstrap techniques for finding collections from Feynman diagrams and matrices from *** applications of the first,we find all 693,13612 and 346710 collections for(k,n)=(3,7),(3,8)and(3,9),*** applications of the second kind,we find all90608 and 30659424 planar matrices that compute(k,n)=(4,8)and(4,9)biadjoint amplitudes,*** an example of the evaluation of matrices of Feynman diagrams,we present the complete form of the(4,8)and(4,9)biadjoint *** also start a study of higher-dimensional arrays of Feynman diagrams,including the combinatorial version of the duality between(k,n)and(n-k,n)objects.

关键词： Feynman diagrams biadjoint amplitudes tropical Grassmannian

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Interactive association between processing induced molecular structure changes and nutrient delivery on a molecular basis,revealed by cutting-edge vibrational biomolecular spectroscopy

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Journal of Animal Science and Biotechnology 2020年第1期11卷 211-226页

作者： Aya Ismael Victor Hugo guevara-Oquendo Basim Refat Peiqiang Yu Ministry of Agriculture Strategic Research Chair(PY)Lab Department of Animal and Poultry ScienceCollege of Agriculture and BioresourcesUniversity of Saskatchewan51 Campus DriveSaskatoonSK S7N 5A8Canada

Background:This study was conducted to determine protein molecular structure profiles and quantify the relationship between protein structural features and protein metabolism and bioavailability of blend pel eted products(BPP)based on co-products(canola or carinata)from processing with different proportions of pulse pea screenings and lignosulfonate chemical ***:The protein molecular structures were determined using the non-invasive advanced vibrational molecular spectroscopy(ATR-FT/IR)in terms of chemical structure and biofunctional groups of amides(ⅠandⅡ),α-helix andβ-***:The results showed that increasing the level of the co-products in BPP significantly increased the spectral intensity of the amide area and amide *** products exhibited similar protein secondaryα-helix toβ-sheet *** protein molecular structure profiles(amidesⅠandⅡ,α-helix toβ-sheet)were highly associated with protein degradation kinetics and intestinal *** conclusion,the non-invasive vibrational molecular spectroscopy(ATR-FT/IR)could be used to detect inherent structural make-up characteristics in ***:The molecular structural features related to protein biopolymer were highly associated with protein utilization and metabolism.

关键词： Alpha-helix and beta-sheet Amides(ⅠandⅡ) Biofunctional groups Chemical structure Protein metabolism and bioavailability Protein molecular structure

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