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Palaeobiogeographical constraints on the distribution of foraminifers and rugose corals in the carboniferous Tindouf Basin,South Morocco

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journal of Palaeogeography 2013年第1期2卷 1-18页

作者： Ian D.Somerville Pedro cózar Ismail Said Daniel Vachard Paula Medina-Varea Sergio rodríguez UcD School of Geological Sciences University College DublinBelfield Dpto.de Geología Sedimentariay cambio Ambiental Instituto de Geociencias (CSICUCM)c/José Antonio Novais28040-Madrid Spain Dpto.de Paleontología Facultad de Ciencias Geológicas Universidad Complutense de Madridc/José Antonio Novais 228040-MadridSpain Université de Lille 1 UMR 8217 du CNRS:GéosystèmesBatiment SN 559655 Villeneuve d'Ascq France Dpto.de Geología Sedimentariay cambio Ambiental Instituto de Geociencias (CSICUCM)c/José Antonio Novais28040-MadridSpain Dpto.de Paleontología Facultad de Ciencias GeológicasUniversidad Complutense de Madridc/José Antonio Novais 228040-MadridSpain

The northern flank of the Tindouf Syncline in southern Morocco exhibits a continuous, well exposed carboniferous succession with limestones of Late Asbian to Early Bashkirian age containing rich and diverse foraminiferal and rugose coral assemblages. Analysis of these assemblages provides new data on the relatively poorly known Saharan basins. The palaeobiogeographical relationship of the Tindouf Basin with other Palaeotethyan basins is complex. Although there is a predominance of cosmopolitan taxa for the Palaeotethys, it is recognized that there was an influence of basins from nW Europe, such as the UK and Ireland. Some taxa are recorded in both nW Europe and Tindouf without any characteristic contributions from intermediate basins in northern Morocco. The neighbouring Béchar Basin in Algeria presents distinct assemblages. The bulk of the data analyzed suggest that this sector of the western Palaeotethys can be subdivided into four palaeobiogeographical subprovinces: the Atlantic Subprovince (UK, Ireland, n France and Belgium), the Mediterranean Subprovince (Pyrenees, Montagne noire, Betic cordillera, rif (n Morocco) and Balearic Islands), and the Saharan Subprovince (Béchar, reggan, Ahnet-Mouydir and Tindouf). In between, mobile belts of mixed faunal assemblage characteristics are observed (e.g., SW Spain and central Meseta) forming the West peri-Gondwanan *** of the Tindouf Basin faunas shows that, as in other Saharan basins, there is a high diversity and abundance of foraminiferal taxa, with a higher proportion of survivors and longer stratigraphic ranges; these features also are mirrored by rugose corals. This emphasizes the longevity of the carbonate platform in a tropical setting, where periodic transgressions introduced new assemblages, and oceanic currents are interpreted as one of the main controlling factors for the distribution of the taxa in these subprovinces. Moreover, not only were water temperatures on the platform higher, but also

关键词： carboniferous palaeobiogeography new subprovinces foraminifers rugose corals Tindouf Basin north Africa

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Photocatalytic performance of K2Ti6O13 whiskers to H2 evolution and cO2 photo-reduction

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journal of Energy chemistry 2019年第10期28卷 18-28页

作者： L. F. Garay-rodríguez L.M.Torres-Martínez E.Moctezuma Facultad de Ingeniería civil-Departamento de Ecomateriales y Energía Universidad Autónoma de Nuevo LeónAv. Universidad S/N Cd. UniversitariaC. P. 66455 San Nicolás de los GarzaNLMéxico Facultad de ciencias Químicas Universidad Autónoma de San Luis PotosíAv. Manuel Nava#6C. P.78290 San Luis PotosíSLPMéxico

K2Ti6O13 whiskers were synthesized by conventional sol-gel method, sono-chemical assisted and microwave assisted sol-gel method in order to obtain catalysts with different particle sizes and to modify their optical, textural and electrochemical properties. These modifications improved their photocatalytic activity for H2 evolution and cO2 photo-reduction. Long K2Ti6O13 whiskers prepared by ultrasound assisted sol-gel method are the most active photocatalysts for the hydrogen evolution reaction using pure water as reactant (U-SG, 10,065 μmol g^-1). In contrast, an opposite behavior was observed using a mixture of ethanol-water, where the highest activity was achieved by the shortest and less crystalline K2Ti6O13 whiskers (c-SG, 3,2871 μmol g^-1). In case of cO2 photo-reduction, long whiskers that were also prepared by the sono-chemical assisted sol-gel method were the most active to transform cO2 to formaldehyde, methane, methanol and hydrogen. The EFB value of this catalyst is located very close to the potential for formaldehyde production and favors the selectivity to this organic product.

关键词： K2Ti6O13 Sol-gel Whiskers Hydrogen evolution cO2 reduction

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Kinetic analysis via mathematical modeling for ferrous iron oxidation in a class of SBr-type system

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chinese journal of chemical Engineering 2019年第10期27卷 2472-2480页

作者： Edgar nTec-caamal refugio rodríguez-Vázquez Luis GTorres-Bustillos ricardo Aguilar-López center for research and Advanced Studies of the national Polytechnic Institute Av.Instituto Politécnico Nacional No.2508Colonia San Pedro ZacatencoC.P.07360 Ciudad de México D.F.Mexico Interdisciplinary Professional Unit of Biotechnology-national Polytechnic Institute(UPIBI-IPn) Acueducto s/nLa Laguna TicománGustavo A.Madero07340Ciudad de MéxicoMexico

This paper analyses the oxidation of ferrous iron via chemical and biological means in a class of Sequential Batch reactors(SBr-type).For this,a kinetic model for the study of iron oxidation system is proposed,followed by a parametric sensitivity analysis and a bifurcation analysis,which allow selecting the most influential kinetic parameters in order to ensure a suitable prediction capacity of the mathematical *** system consists of two SBr bioreactors,the first being used to produce hydrogen peroxide(H2O2)that is fed to a second reactor where the iron oxidation is carried out by chemical–biological *** predictions were compared with experimental data for the production of H2O2 and for ferrous iron oxidation,finding suitable correlation coefficients(r2 n 0.98)for each state *** bifurcation analysis showed the trajectories of the main variables,such as,biomass,H2O2 and ferrous iron,under the change of the most influential kinetic *** analysis demonstrates the usefulness of the constructed model to predict the kinetic behaviour of the SBr-type process.

关键词： Bifurcation analysis Hydrogen peroxide Iron oxidation Modeling Simulation

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Opposing roles of plant laticifer cells in the resistance to insect herbivores and fungal pathogens

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Plant communications 2021年第3期2卷 93-104页

作者： Lourdes castelblanque javier García-Andrade clara Martínez-Arias juan j.rodríguez Francisco j.Escaray Ernestina Aguilar-Fenollosa josep A.jaques Pablo Vera Instituto de Biología Moleculary celular de Plantas Universitat Politécnica de Valéncia-C.S.I.CCiudad Politécnica de la InnovaciònEdificio 8EIngeniero Fausto Elios/n46022 ValenciaSpain Universitat jaume I Departament de Ciéncies Agráries i del Medi NaturalCampus del Riu Sec12003 Castellòde la PlanaSpain

More than 12,000 plant species(ca.10%of flowering plants)exude latex when their tissues are *** is produced and stored in specialized cells named“laticifers”.Laticifers form a tubing system composed of rows of elongated cells that branch and create an internal network encompassing the entire *** constitute a recent evolutionary achievement in ecophysiological adaptation to specific natural environments;however,their fitness benefit to the plant still remains to be *** identification of Euphorbia lathyris mutants(pil mutants)deficient in laticifer cells or latex metabolism,and therefore compromised in latex production,allowed us to test the importance of laticifers in pest *** provided genetic evidence indicating that laticifers represent a cellular adaptation for an essential defense strategy to fend off arthropod herbivores with different feeding habits,such as Spodoptera exigua and Tetranychus *** marked contrast,we also discovered that a lack of laticifer cells causes complete resistance to the fungal pathogen Botrytis ***,a latex-derived factor required for conidia germination on the leaf surface was *** factor promoted disease susceptibility enhancement even in the non-latex-bearing plant *** speculate on the role of laticifers in the coevolutionary arms race between plants and their enemies.

关键词： latex Euphorbia lathyris disease resistance disease susceptibility plant defense

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MEP pathway products allosterically promote monomerization of deoxy-D-xylulose-5-phosphate synthase to feedback-regulate their supply

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Plant communications 2023年第3期4卷 171-182页

作者： supply Xueni Di David Ortega-Alarcon ramu Kakumanu javier Iglesias-Fernandez Lucia Diaz Edward E.K.Baidoo Adrian Velazquez-campoy Manuel rodríguez-concepción jordi Perez-Gil Institute for Plant Molecular and cell Biology(IBMcP) CSIC-Universitat Politècnica de València46022 ValenciaSpain 2Centre for Research in Agricultural Genomics(CRAG)CSIC-IRTA-UAB-UBCampus UAB Bellaterra08193 BarcelonaSpain 3Institute for Biocomputation and Physics of Complex Systems(BIFI)Joint Unit GBsC-CSIC-BIFIUniversidad de Zaragoza50009 ZaragozaSpain 4Departamento de Bioquímica y Biología Molecular y CelularUniversidad de Zaragoza50009 ZaragozaSpain 5Joint BioEnergy Institute5885 Hollis StreetEmeryvilleCA 94608USA 6Biological Systems and Engineering DivisionLawrence Berkeley National LaboratoryBerkeleyCA 94720USA 7Nostrum Biodiscovery SL08029 BarcelonaSpain 8Instituto de Investigación Sanitaria de Aragón(IIS Aragon)50009 ZaragozaSpain 9Centro de Investigación Biomédica en Red en elÁrea Temática de Enfermedades Hepáticas y Digestivas(CIBERehd)28029 MadridSpain

Isoprenoids are a very large and diverse family of metabolites required by all living *** isoprenoids derive fromthe double-bond isomers isopentenyl diphosphate(IPP)and dimethylallyl diphosphate(DMAPP),which are produced by the methylerythritol 4-phosphate(MEP)pathway in bacteria and plant *** has been reported that IPP and DMAPP feedback-regulate the activity of deoxyxylulose 5-phosphate synthase(DXS),a dimeric enzyme that catalyzes the main flux-controlling step of the MEP *** we provide experimental insights *** titration calorimetry and dynamic light scattering approaches showed that IPP and DMAPP can allosterically bind to DXS in vitro,causing a size *** silico ligand binding site analysis and docking calculations identified a potential allosteric site in the contact region between the two monomers of the active DXS *** of IPP and DMAPP contents in vivo followed by immunoblot analyses confirmed that high IPP/DMAPP levels resulted in monomerization and eventual aggregation of the enzyme in bacterial and plant *** of the enzymatically active dimeric conformation allows a fast and reversible reduction of DXS activity in response to a sudden increase or decrease in IPP/DMAPP supply,whereas aggregation and subsequent removal of monomers that would otherwise be available for dimerization appears to be a more drastic response in the case of persistent IPP/DMAPP overabundance(e.g.,by a blockage in their conversion to downstream isoprenoids).Our results represent an important step toward understanding the regulation of the MEP pathway and rational design of biotechnological endeavors aimed at increasing isoprenoid contents in microbial and plant systems.

关键词： isoprenoids DXS feedback regulation allosteric monomerization

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Twenty years of population dynamics in European beech-oak forest at their rear range margin anticipate changes in its structure and composition

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Forest Ecosystems 2024年第3期11卷 358-370页

作者： álvaro rubio-cuadrado Iciar Alberdi Isabel canellas Fernando Montes jesús rodríguez-calcerrada rosana López Guillermo G.Gordaliza María Valbuena-carabana nikos nanos ramón Perea Luis Gil Departamento de dinamica y gestion forestal Instituto de Ciencias Forestales(ICIFOR-INIA)CSICCtra.La Coruna km 7.528040MadridSpain Departamento de Sistemas y recursos naturales Escuela Tecnica Superior de Ingeniería de MontesForestal y del Medio NaturalUniversidad Politecnica de Madrid.Ciudad Universitaria s/n28040MadridSpain School of Forestry and natural Environment Aristotle University of ThessalonikiUniversity Campus54124ThessalonikiGreece

There is an increasing interest in restoring degraded forests,which occupy half of the forest *** the forms of restoration,passive restoration,which involves the elimination of degrading factors and the free evolution of natural dynamics by applying minimal or no management,is gaining *** dynamics is difficult to predict due to the influence of multiple interacting factors such as climatic and edaphic conditions,composition and abundance of species,and the successional character of these ***,we study the natural dynamics of a mixed forest located in central Spain,which maintained an open forest structure,due to intensive use,until grazing and cutting were banned in the *** most frequent woody species in this forest are Fagus sylvatica,Quercus petraea,Quercus pyrenaica,Ilex aquifolium,Sorbus aucuparia,Sorbus aria and Prunus avium,with contrasting shade and drought *** species are common in temperate European deciduous forest and are found here near their southern distribution limit,except for *** order to analyze forest dynamics and composition,three inventories were carried out in 1994,2005 and *** results show that,despite the Mediterranean influence,the natural dynamics of this forest has been mainly determined by different levels of shade *** the abandonment of grazing and cutting,*** expanded rapidly due to its lower shade tolerance,whereas after canopy closure and forest densification,shade-tolerant species gained ground,particularly ***,despite its lower drought and late-frost *** the current dynamics continue,*** will overtake the rest of the species,which will be relegated to sites with shallow soils and steep ***,all the multi-centennial beech trees,which are undergoing a rapid mortality and decline process,will disappear.

关键词： Forest succession Secondary forest Woodland Mixed forest competition recruitment

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Machine learning applications on lunar meteorite minerals:From classification to mechanical properties prediction

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International journal of Mining Science and Technology 2024年第9期34卷 1283-1292页

作者： Eloy Peña-Asensio josep M.Trigo-rodríguez jordi Sort jordi Ibáñez-Insa Albert rimola Department of Aerospace Science and Technology Politecnico di MilanoMilano 20156Italy Institut de ciències de l’Espai(IcE-cSIc) Campus UAB08193 Cerdanyola del VallèsSpain Institut d’Estudis Espacials de catalunya(IEEc) Barcelona 08034Spain Departament de Física Universitat Autònoma de BarcelonaCerdanyola del Vallès E-08193Spain Instituciócatalana de recerca i Estudis Avançats(IcrEA) Barcelona E-08010Spain Geosciences Barcelona(GEO3Bcn-cSIc) E-08028 BarcelonaSpain Departament de Química Universitat Autònoma de BarcelonaBellaterra 08193Spain

Amid the scarcity of lunar meteorites and the imperative to preserve their scientific value,nondestructive testing methods are *** translates into the application of microscale rock mechanics experiments and scanning electron microscopy for surface composition *** study explores the application of Machine Learning algorithms in predicting the mineralogical and mechanical properties of DHOFAr 1084,jAH 838,and nWA 11444 lunar meteorites based solely on their atomic percentage *** a prior-data fitted network model,we achieved near-perfect classification scores for meteorites,mineral groups,and individual *** regressor models,notably the Kneighbor model,provided an outstanding estimate of the mechanical properties—previously measured by nanoindentation tests—such as hardness,reduced Young’s modulus,and elastic *** considerations on the nature and physical properties of the minerals forming these meteorites,including porosity,crystal orientation,or shock degree,are essential for refining *** findings underscore the potential of Machine Learning in enhancing mineral identification and mechanical property estimation in lunar exploration,which pave the way for new advancements and quick assessments in extraterrestrial mineral mining,processing,and research.

关键词： Meteorites Moon Mineralogy Machine learning Mechanical properties

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numerical Study of the Distribution of Temperatures and relative Humidity in a Ventilated room Located in Warm Weather

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computer Modeling in Engineering & Sciences 2020年第5期123卷 571-602页

作者： j.Serrano-Arellano j.M.Belman-Flores I.Hernández-Pérez K.M.Aguilar-castro E.V.Macías-Melo F.Elizalde-Blancas j.M.riesco-Ávila F.j.García-rodríguez Instituto Tecnológico Superior de Huichapan El SaucilloHuichapan42411México Universidad de Guanajuato Palo BlancoSalamanca36885México Universidad juárez Autónoma de Tabasco CunduacánTabasco86690México Instituto Tecnológico de celaya Col.FovisssteCelaya38010México

In the present study,an analysis of the heat and mass transfer in a ventilated cavity in a warm climate zone was carried out to analyze,among others,the temperatures and percentage of relative humidity(rH).The governing equations of the mathematical model were solved through the finite volume *** used the k-εturbulence mode to find the results of the variables of interest in seven climate records on a given *** velocity of the inlet flow of the air-H2O mixture was varied through the reynolds number(re)from 500 to *** outdoor weather conditions considered were solar radiation,ambient temperature,and *** was found that at low velocities,flow recirculation was formed inside the cavity which increased the temperature and concentration of *** re=5000 the flow is predominantly forced,which tends to set the values of temperature and rH as 20°c and 20%*** values of the rH increase in the afternoon hours when the solar radiation decreases to the value of ***,the mass transfer through the values of Sh is maintained with similar values in the seven weather *** was concluded that when air conditioning supplies air at speeds higher than 0.26 m/s at low temperatures it produces cooling with low rH,this causes discomfort,illness and/or discomfort to the users.

关键词： Heat transfer mass transfer solar radiation turbulence

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Proteomics for discovery of candidate colorectal cancer biomarkers

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World journal of Gastroenterology 2014年第14期20卷 3804-3824页

作者： Paula lvarez-chaver Olalla Otero-Estévez María Páez de la cadena Francisco j rodríguez-Berrocal Vicenta S Martínez-Zorzano Unidad de Proteómica Servicio de Determinación EstructuralProteómica y GenómicaCentro de Apoyo Científico y Tecnológico a la InvestigaciónUniversidad de VigoCampus As Lagoas-Marcosende área de Bioquímica y Biología Molecular Departamento de BioquímicaGenética e InmunologíaFacultad de BiologíaUniversidad de VigoCampus As Lagoas-Marcosende

colorectal cancer(crc)is the second most common cause of cancer-related deaths in Europe and other Western countries,mainly due to the lack of wellvalidated clinically useful biomarkers with enough sensitivity and specificity to detect this disease at early *** it is well known that the pathogenesis of crc is a progressive accumulation of mutations in multiple genes,much less is known at the proteome ***,in the last years many proteomic studies have been conducted to find new candidate protein biomarkers for diagnosis,prognosis and as therapeutic targets for this malignancy,as well as to elucidate the molecular mechanisms of colorectal *** important advantage of the proteomic approaches is the capacity to look for multiple differentially expressed proteins in a single *** review provides an overview of the recent reports describing the different proteomic tools used for the discovery of new protein markers for crc such as two-dimensional electrophoresis methods,quantitative mass spectrometry-based techniques or protein ***,we will also focus on the diverse biological samples used for crc biomarker discovery such as tissue,serum and faeces,besides cell lines and murine models,discussing their advantages and disadvantages,and summarize the most frequently identified candidate crc markers.

关键词： colorectal cancer Serum Tissue Proteins Biomarkers Proteomics Protein identification Mass spectrometry

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Observation of the crab nebula with LHAASO-KM2A−a performance study

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chinese Physics c 2021年第2期45卷 518-530页

作者： F.Aharonian Q.An Axikegu L.X.Bai Y.X.Bai Y.W.Bao D.Bastieri X.j.Bi Y.j.Bi H.cai j.T.cai Z.cao j.chang j.F.chang X.c.chang B.M.chen j.chen L.chen M.j.chen M.L.chen Q.H.chen S.H.chen S.Z.chen T.L.chen X.L.chen Y.chen n.cheng Y.D.cheng S.W.cui X.H.cui Y.D.cui B.Z.Dai H.L.Dai Z.G.Dai D.della Volpe B.D'Ettorre Piazzoli X.j.Dong j.H.Fan Y.Z.Fan Z.X.Fan j.Fang K.Fang c.F.Feng L.Feng S.H.Feng Y.L.Feng B.Gao c.D.Gao Q.Gao W.Gao M.M.Ge L.S.Geng G.H.Gong Q.B.Gou M.H.Gu j.G.Guo X.L.Guo Y.Q.Guo Y.Y.Guo Y.A.Han H.H.He H.n.He j.c.He S.L.He X.B.He Y.He M.Heller Y.K.Hor c.Hou X.Hou H.B.Hu S.Hu S.c.Hu X.j.Hu D.H.Huang Q.L.Huang W.H.Huang X.T.Huang Z.c.Huang F.ji X.L.ji H.Y.jia K.jiang Z.j.jiang c.jin D.Kuleshov K.Levochkin B.B.Li c.Li F.Li H.B.Li H.c.Li H.Y.Li j.Li K.Li W.L.Li X.Li X.r.Li Y.Li Y.Z.Li Z.Li E.W.Liang Y.F.Liang S.j.Lin B.Liu c.Liu D.Liu H.Liu H.D.Liu j.Liu j.L.Liu j.S.Liu j.Y.Liu M.Y.Liu r.Y.Liu S.M.Liu W.Liu Y.n.Liu Z.X.Liu W.j.Long r.Lu H.K.Lv B.Q.Ma L.L.Ma X.H.Ma j.r.Mao A.Masood W.Mitthumsiri T.Montaruli Y.c.nan B.Y.Pang P.Pattarakijwanich Z.Y.Pei M.Y.Qi D.ruffolo V.rulev A.Sáiz L.Shao O.Shchegolev X.D.Sheng j.r.Shi H.c.Song Yu.V.Stenkin V.Stepanov Q.n.Sun X.n.Sun Z.B.Sun P.H.T.Tam Z.B.Tang W.W.Tian B.D.Wang c.Wang H.Wang H.G.Wang j.c.Wang j.S.Wang L.P.Wang L.Y.Wang r.n.Wang W.Wang X.G.Wang X.j.Wang X.Y.Wang Y.D.Wang Y.j.Wang Y.P.Wang Z.Wang Z.H.Wang Z.X.Wang D.M.Wei j.j.Wei Y.j.Wei T.Wen c.Y.Wu H.r.Wu S.Wu W.X.Wu X.F.Wu S.Q.Xi j.Xia j.j.Xia G.M.Xiang G.Xiao H.B.Xiao G.G.Xin Y.L.Xin Y.Xing D.L.Xu r.X.Xu L.Xue D.H.Yan c.W.Yang F.F.Yang j.Y.Yang L.L.Yang M.j.Yang r.Z.Yang S.B.Yang Y.H.Yao Z.G.Yao Y.M.Ye L.Q.Yin n.Yin X.H.You Z.Y.You Y.H.Yu Q.Yuan H.D.Zeng T.X.Zeng W.Zeng Z.K.Zeng M.Zha X.X.Zhai B.B.Zhang H.M.Zhang H.Y.Zhang j.L.Zhang j.W.Zhang L.Zhang L.X.Zhang P.F.Zhang P.P.Zhang r.Zhang S.r.Zhang S.S.Zhang X.Zhang X.P.Zhang Y.Zhang Y.F.Zhang Y.L.Zhang B.Zhao j.Zhao L.Zhao L.Z.Zhao S.P.Zhao F.Zheng Y.Zheng B.Zhou H.Zhou j.n.Zhou P.Zhou r.Zhou X.X.Zhou c.G.Zhu F.r.Zhu H.Zhu K.j.Zhu X.Zuo Key Laboratory of Particle Astrophyics&Experimental Physics Division&computing center Institute of High Energy PhysicsChinese Academy of Sciences100049 BeijingChina University of chinese Academy of Sciences 100049 BeijingChina TIAnFU cosmic ray research center ChengduSichuanChina State Key Laboratory of Particle Detection and Electronics China University of Science and Technology of china 230026 HefeiAnhuiChina Department of Engineering Physics Tsinghua University100084 BeijingChina national Astronomical Observatories Chinese Academy of Sciences100101 BeijingChina national Space Science center Chinese Academy of Sciences100190 BeijingChina School of Physics Peking University100871 BeijingChina center for Astrophysics Guangzhou University510006 GuangzhouGuangdongChina School of Physics and Astronomy&School of Physics(Guangzhou) Sun Yat-sen University519000 ZhuhaiGuangdongChina School of Physical Science and Technology Guangxi University530004 NanningGuangxiChina Hebei normal University 050024 ShijiazhuangHebeiChina School of Physics and Microelectronics Zhengzhou University450001 ZhengzhouHenanChina School of Astronomy and Space Science Nanjing University210023 NanjingJiangsuChina Key Laboratory of Dark Matter and Space Astronomy Purple Mountain ObservatoryChinese Academy of Sciences210023 NanjingJiangsuChina Institute of Frontier and Interdisciplinary Science Shandong University266237 QingdaoShandongChina Key Laboratory for research in Galaxies and cosmology Shanghai Astronomical ObservatoryChinese Academy of Sciences200030 ShanghaiChina Tsung-Dao Lee Institute&School of Physics and Astronomy Shanghai Jiao Tong University200240 ShanghaiChina School of Physical Science and Technology&School of Information Science and Technology Southwest Jiaotong University610031 ChengduSichuanChina college of Physics Sichuan University610065 ChengduSichuanChina Key Laboratory of cosmic rays(Tibet University) Ministry of Education850000 LhasaTibetChina School of Physics and Tec

A sub-array of the Large High Altitude Air Shower Observatory(LHAASO),KM2A is mainly designed to observe a large fraction of the northern sky to hunt for γ-ray sources at energies above 10 *** though the detector construction is still underway,half of the KM2A array has been operating stably since the end of *** this paper,we present the KM2A data analysis pipeline and the first observation of the crab nebula,a standard candle in very high energy γ-ray *** detect γ-ray signals from the crab nebula in both energy ranges of 10-100 TeV and>100 TeV with high significance,by analyzing the KM2A data of 136 live days between December 2019 and May *** the observations,we test the detector performance,including angular resolution,pointing accuracy and cosmic-ray background rejection *** energy spectrum of the crab nebula in the energy range 10-250 TeV fits well with a single power-law function dn/dE=(1.13±0.05stat±0.08sys)×10^(-14).(E/20 TeV)-309±0.06stat±0.02syscm^(-2) s^(-1) TeV^(-1).It is consistent with previous measurements by other *** opens a new window of γ-ray astronomy above 0.1 PeV through which new ultrahigh-energy γ-ray phenomena,such as cosmic PeVatrons,might be discovered.

关键词： γ-ray crab nebula extensive air showers cosmic rays

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