检索结果-南通市图书馆

Litter production and leaf nutrient concentration and remobilization in response to climate seasonality in the central Amazon

在线全文

学校读者我要写书评

暂无评论

Journal of Forestry Research 2024年第3期35卷 131-141页

作者： Ricardo Antonio marenco Saul Alfredo Antezana-Vera Daniela Pereira dias Luiz Antonio Candido Instituto Nacional de Pesquisas da Amazonia Coordenagao de Uso da Terra e Mudanca ClimaticaAv.Andre Araujo 2936ManausAM69067-375Brazil Programa de pos-Graduagao em Agricultura no Tropico Umido Instituto Nacional de Pesquisas da Amazonia-INPAManausAMBrazil Unidade Academica de Ciencias Agrarias Universidade Federal de JataiBR 364km 195JataiGO 75801-615Brazil

Litterfall is the largest source of nutrients to for-est soils of tropical ***,variability in lit-terfall production,nutrient remobilization,and changes in leaf nutrient concentration with climate seasonality remain largely unknown for the central *** study meas-ured litterfall production,leaf nutrient remobilization,and leaf area index on a forest plateau in the central *** was measured at monthly intervals during 2014,while nitrogen,phosphorus,potassium,calcium and mag-nesium concentrations of leaf litter and canopy leaves were measured in the dry and rainy seasons,and remobilization rates *** area index was also recorded in the dry and rainy *** litterfall varied from 33.2(in the rainy season)to 87.6 g m^(-2) in the dry season,while leaf area index increased slightly in the rainy *** seasonality had no effect on concentrations of nitrogen,calcium,and magnesium,whereas phosphorous and potassium responded to rainfall seasonality *** phosphorous increased,potassium decreased during the dry *** seasons,nitrogen,potassium,and phosphorous decreased in leaf litter;calcium increased in leaf litter,while magnesium remained unaffected with leaf ***,the five nutrients had similar remobilization rates over the *** absence of climate seasonality on nutrient remobilization suggests that the current length of the dry season does not alter nutrient remobilization rates but this may change as dry periods become more prolonged in the future due to climate change.

关键词： Throughfall Nutrient cycling Climatic seasonality Leaf mass per area

Deterministic and probabilistic analysis of great-depth braced excavations:A 32 m excavation case study in Paris

在线全文

学校读者我要写书评

暂无评论

Journal of Rock mechanics and Geotechnical Engineering 2024年第5期16卷 1505-1521页

作者： Tingting Zhang Julien Baroth Daniel dias Khadija Nejjar Université Grenoble Alpes CNRSGrenoble INP3SRGrenoble38000France Antea Group Antony92160France School of Automotive and Transportation Engineering Hefei University of TechnologyHefei23009China Terrasol 42-52 Quai de la RapéeParis75012France

The Fort d’Issy-Vanves-Clamart(FIVC)braced excavation in France is analyzed to provide insights into the geotechnical serviceability assessment of excavations at great depth within deterministic and probabilistic *** FIVC excavation is excavated at 32 m below the ground surface in Parisian sedimentary basin and a plane-strain finite element analysis is implemented to examine the wall deflections and ground surface settlements.A stochastic finite element method based on the polynomial chaos Kriging metamodel(mSFEm)is then proposed for the probabilistic *** with field measurements and former studies are carried *** academic cases are then conducted to investigate the great-depth excavation stability regarding the maximum horizontal wall deflection and maximum ground surface *** results indicate that the proposed mSFEm is effective for probabilistic analyses and can provide useful insights for the excavation design and construction.A sensitivity analysis for seven considered random parameters is then *** soil friction angle at the excavation bottom layer is the most significant one for *** soil-wall interaction effects on the excavation stability are also given.

关键词： Braced deep excavation Soil-wall interaction Stochastic finite element method Horizontal wall deflection Settlement Failure probability

Aseismic performances of constrained damping lining structures made of rubber-sand-concrete

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Rock mechanics and Geotechnical Engineering 2024年第5期16卷 1522-1537页

作者： Xiancheng mei Qian Sheng Jian Chen Zhen Cui Jianhe Li Chuanqi Li Daniel dias State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China University of Chinese Academy of Sciences Beijing100049China Key Laboratory of Water Grid Project and Regulation of ministry of Water Resources Changjiang Institute of SurveyPlanningDesign and ResearchWuhan430010China Laboratory 3SR CNRS UMR 5521Grenoble Alpes UniversityGrenoble38000France School of Automotive and Transportation Engineering Hefei University of TechnologyHefei23009China

Flexible damping technology considering aseismic materials and aseismic structures seems be a good solution for engineering *** this study,a constrained damping structure for underground tunnel lining,using a rubber-sand-concrete(RSC)as the aseismic material,is *** aseismic performances of constrained damping structure were investigated by a series of hammer impact *** damping layer thickness and shape effects on the aseismic performance such as effective duration and acceleration amplitude of time-domain analysis,composite loss factor and damping ratio of the transfer function analysis,and total vibration level of octave spectrum analysis were *** hammer impact tests revealed that the relationship between the aseismic performance and damping layer thickness was not linear,and that the hollow damping layer had a better aseismic performance than the flat damping layer *** aseismic performances of constrained damping structure under different seismicity magnitudes and geological conditions were *** effects of the peak ground acceleration(PGA)and tunnel overburden depth on the aseismic performances such as the maximum principal stress and equivalent plastic strain(PEEQ)were *** numerical results show the constrained damping structure proposed in this paper has a good aseismic performance,with PGA in the range(0.2-1.2)g and tunnel overburden depth in the range of 0-300 m.

关键词： Constrained damping structure Aseismic performance Hammer impact tests Damping layer Peak ground acceleration Overburden depth

Solvability and Construction of a Solution to the Fredholm Integral Equation of the First Kind

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Applied mathematics and Physics 2024年第2期12卷 720-735页

作者： Aisagaliev Serikbai Nurmagambetov dias Sevryugin Ilya Differential Equations and Control Theory Al-Farabi Kazakh National University Almaty Kazakhstan Department of mathematics Prairie View A&M University Prairie View USA

The issues of solvability and construction of a solution of the Fredholm integral equation of the first kind are considered. It is done by immersing the original problem into solving an extremal problem in Hilbert space. Necessary and sufficient conditions for the existence of a solution are obtained. A method of constructing a solution of the Fredholm integral equation of the first kind is developed. A constructive theory of solvability and construction of a solution to a boundary value problem of a linear integrodifferential equation with a distributed delay in control, generated by the Fredholm integral equation of the first kind, has been created.

关键词： Integral Equations Solvability Solution Construction Controllability minimizing Sequences

Driving factors behind multiple populations

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China(Physics,mechanics & Astronomy) 2024年第5期67卷 172-181页

作者： Ruoyun Huang Baitian Tang Chengyuan Li Doug Geisler mario mateo Ying-Yi Song Holger Baumgardt Julio A.Carballo-Bello Yue Wang Jundan Nie Bruno dias JoséG.Fernández-Trincado School of Physics and Astronomy Sun Yat-sen UniversityZhuhai 519082China CSST Science Center for the Guangdong-Hong Kong-macao Greater Bay Area Zhuhai 519082China Departamento de Astronomía Universidad de ConcepcionConcepcionChile Instituto de Investigación multidisciplinario en Ciencia y Tecnología Universidad de La SerenaLa SerenaChile Departamento de Astronomía Facultad de CienciasUniversidad de La SerenaChile Department of Astronomy University of MichiganAnn Arbor 48109USA David A.Dunlap Department of Astronomy&Astrophysics University of TorontoToronto ON M5S 3H4Canada Dunlap Institute for Astronomy&Astrophysics University of TorontoToronto ON M5S 3H4Canada School of mathematics and Physics The University of QueenslandSt.Lucia QLD 4072Australia Instituto de Alta Investigación Universidad de TarapacáAricaChile CAS Key Laboratory of Optical Astronomy National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China Instituto de Astrofísica Departamento de Ciencias FísicasFacultad de Ciencias ExactasUniversidad Andres BelloSantiagoChile Instituto de Astronomía Universidad Católica del NorteAntofagastaChile

Star clusters were historically considered simple stellar populations,with all stars sharing the same age and initial chemical ***,the presence of chemical anomalies in globular clusters(GCs),called multiple stellar populations(mPs),has challenged star formation theories in dense *** studies show that mass,metallicity,and age are likely controlling parameters for the manifestation of *** the limit between clusters with/without mPs in physical parameter space is crucial to reveal the driving mechanism behind their *** this study,we look for mP signals in Whiting 1,which is traditionally considered a young *** the magellan telescope,we obtained low-resolution spectra withinλλ=3850-5500?for eight giants of Whiting *** measured the C and N abundances from the CN and CH spectral indices.C and N abundances have variations comparable with their measurement errors(~0.1 dex),suggesting that mPs are absent from Whiting *** these findings with literature studies,we propose a limit in the metallicity *** compactness index parameter space,which relatively clearly separates star clusters with/without mPs(GCs/open clusters).This limit is physically *** a larger scale,the galactic environment determines cluster compactness and metallicity,leading to metal-rich,diffuse,old clusters formed ex *** proposed limit also impacts our understanding of the formation of the Sagittarius dwarf galaxy:star clusters formed after the first starburst(age≤8-10 Gyr).These clusters are simple stellar populations because the enriched galactic environment is no longer suitable for mP formation.

关键词： stellar galactic galaxy

Seasonal variation and host sex affect bat–bat fly interaction networks in the Amazonian savannahs

在线全文

学校读者我要写书评

暂无评论

Integrative Zoology 2024年第3期19卷 400-416页

作者： Paulo mEJIA Gustavo Lima URBIETA Bruna da Silva XAVIER IsaíJorge de CASTRO JoséJúlio DE TOLEDO Gustavo GRACIOLLI Lucio AndréVIANA dias William Douglas CARVALHO Programa de Pós-Graduação em Biodiversidade Tropical Universidade Federal do Amapá(UNIFAP)MacapáAPBrazil Programa de Pós-Graduação em Ecologia Instituto de BiologiaCentro de Ciências da SaúdeUniversidade Federal do Rio de Janeiro(UFRJ)Rio de JaneiroRJBrazil Laboratório de mamíferos Instituto de Pesquisas Científicas e Tecnológicas do Estado do Amapá(IEPA)MacapáAPBrazil Programa de Pós-Graduação em Biologia Animal Laboratório de SistemáticaEcologia e Evolução(LSEE)Instituto de BiociênciasUniversidade Federal de Mato Grosso do Sul(UFMS)Campo GrandeMTBrazil Terrestrial Ecology Group(TEG-UAm) Departamento de EcologíaFacultad de CienciasUniversidad Autónoma de MadridMadridSpain Centro de Investigación en Biodiversidad y Cambio Global(CIBC-UAm) Universidad Autónoma de MadridMadridSpain

Bats are the second-most diverse group of mammals in the world,and bat flies are their main ***,significant knowledge gaps remain regarding these antagonistic interactions,especially since diverse factors such as seasonality and host sex can affect their network ***,we explore the influence of such factors by comparing species richness and composition of bat flies on host bats,as well as specialization and modularity of bat–bat fly interaction networks between seasons and adult host *** captured bats and collected their ectoparasitic flies at 10 sampling sites in the savannahs of AmapáState,northeastern region of the Brazilian *** female bats being more parasitized and recording greater bat fly species richness in the wet season,neither relationship was statistically *** pooled network could be divided into 15 compartments with 54 links,and all subnetworks comprised>12 *** total number of links ranged from 27 to 48(for the dry and wet seasons,respectively),and female and male subnetworks had 44 and 41 links,*** values were very low for the pooled network and for all *** results revealed higher bat fly species richness and abundance in the wet season,whereas specialization and modularity were higher in the dry ***,the subnetwork for female bats displayed higher specialization and modularity than the male ***,both seasonality and host sex contribute in different ways to bat–bat fly network *** studies should consider these factors when evaluating bat–bat fly interaction networks.

关键词： Amapá Amazon biome bat flies bats interaction networks

Arlenea delicata *** ***.,a new ephedroid plant from the Early Cretaceous Crato Formation,Araripe Basin,Northeast Brazil

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Plant Diversity 2024年第3期46卷 362-371页

作者： Alita maria Neves Ribeiro Yong Yang Antonio Alamo Feitosa Saraiva Renan Alfredo machado Bantim joao Tavares Calixto Junior Flaviana Jorge de Lima Programa de Pos-Graduaçao em Diversidade Biologica e Recursos Naturais Universidade Regional do CaririRua Carolino SucupiraPimenta63105-160CratoCearaBrazil Co-Innovation Center for Sustainable Forestry in Southern China College of Biology and the Environment159 Longpan RoadNanjing Forestry UniversityNanjing210037China Laboratorio de Paleontologia Universidade Regional do CaririRua Carolino SucupiraPimenta63105-160CratoCearaBrazil Laboratorio de Estudos da Flora Regional Universidade Regional do CaririRua Carolino SucupiraPimenta63105-160CratoCearaBrazil Gondwanan Plants Lab Universidade Federal de PernambucoCentro Academico de VitoriaRua Do Alto Reservatorio S/nBela Vista55608-680Vitoria de Santo AntaoPernambucoBrazil Programa de Pos-Graduaçao em Geociencias(PPGEOC) Universidade Federal de Pernambuco(UFPE)Rua Av.da ArquiteturaS/n°CEP-50740-550Cidade UniversitariaRecifePernambucoBrazil

Ephedroid macrofossils have been widely documented in Cretaceous deposits,including numerous from the Lower Cretaceous Yixian Formation of NE ***,few ephedroid macrofossils have been reported from South ***,we describe a new plant of the family Ephedraceae,Arlenea delicata *** ***.,from the Lower Cretaceous Crato Formation of the Araripe Basin,Northeast Brazil,based on the vegetative and reproductive *** has the typical morphological characteristics of ephedroid plants,including fertile reproductive branches,opposite phyllotaxy,terminal female cones,a sympodial branching system,longitudinally striated internodes,and swollen *** new finding is unusual in having inner chlamydosperms subtended by two pairs of bracts,reproductive units connected to branches through swollen receptacles and a smooth seed *** new ephedroid taxon from the Crato Formation increases our understanding of plant diversity of this group during the Early ***,the general morphology(fleshy bracts and enlarged receptacles)of this new fossil discovery indicates that seeds of this plant may have been dispersed by animals such as pterosaurs(mainly the Tapejaridae)and birds(Enantiornithes and Ornituromorpha).If true,this would explain the cosmopolitan distribution of Ephedraceae in the Lower Cretaceous.

关键词： Early Cretaceous Gnetophytes Arlenea delicata Ephedrales Crato Formation

^(222)Rn calibration procedure for water analyses by liquid scintillation counting

在线全文

学校读者我要写书评

暂无评论

辐射探测技术与方法(英文) 2023年第2期7卷 311-319页

作者： Ana Rita Gomes Sérgio dias Anabela mourato joao Abrantes mário Reis Laboratório de Protecao e Seguranca Radiológica Instituto Superior TécnicoUniversidade de LisboaEstrada Nacional 10km 13972695‑066 Bobadela LRSPortugal Laboratórios de massa e massa Volúmica de Sólidos Instituto Portugues da QualidadeRua António Giao22829‑513 CaparicaPortugal Centro de Ciências e Tecnologias Nucleares Instituto Superior TécnicoUniversidade de LisboaEstrada Nacional 10km 13972695‑066 Bobadela LRSPortugal

Purpose Among the several methods to measure ^(222)Rn in water,the liquid scintillation counting(LSC)technique is one of the most sensitive and widely used when analysing non-saline waters by liquid extraction,providing excellent accuracy,precision and low-level detection *** using the liquid scintillation counter Tri-Carb 3170 TR/SL(Perkin-Elmer)it is not possible to make an automatic determination of the alpha/beta discrimination parameter,being necessary to evaluate the pulse decay discriminator(PDD)value manually to the ^(222)Rn *** this work,we describe the steps to perform the calibration of that type of *** The method consists in the preparation of standard samples from a ^(226)Ra certified standard solution and the adjustment of the PDD value by hand until the percentage of alpha events reaches a plateau of a near-constant fraction of total *** process consists in taking several measures between PDD 80 and 200 with 15 min counting time *** the plateau,the alpha/beta ratio was used to determine the plateau final range as well as the optimum PDD *** that,the calibration standards and blanks were measured and the region of interest(ROI)was established by finding the maximum value for the figure of merit(FOm)in the upper and lower *** The optimal PDD value of 148 was established by the alpha/beta ratio,and after that,it was possible to measure ^(226)Ra standards to perform the *** efficiency of(9.758±0.035)×1^(0-1) was *** routine measurements,a detection limit of about 0.50 Bq L^(-1) is achieved for a 120 min counting *** evaluate the uncertainty budget,the uncertainties of the net count rate,the efficiency,the sample amount and the decay correction factor were *** A method was developed for the calibration of LSC Tri-Carb 3170 TR/SL with the optimization of the PDD using a ^(226)Ra standard *** acquisition to obtain the plot of the variation

关键词： Radon Waters Pulse decay discriminator Liquid scintillation counting Calibration

The neuroprotective effect of traditional Chinese medicinal plants--A critical review

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Pharmaceutica Sinica B 2023年第8期13卷 3208-3237页

作者： joao moreira mariana machado monica dias-Teixeira Ricardo Ferraz Cristina Delerue-matos Clara Grosso REQUImTE/LAQV Instituto Superior de Engenharia do PortoInstituto Politecnico do PortoPorto 4249-015Portugal Ciencias Químicas e das Biomoleculas/CISA Escola Superior de SaudedInstituto Politecnico do PortoPorto 4200-072Portugal NICiTeS-Nucleo de Investigacao em Ciencias e Tecnologias da Saude Escola Superior de Saude Ribeiro SanchesLisboa 1950-396Portugal REQUImTE/LAQV Departamento de Química e Bioquímica Faculdade de CienciasUniversidade do PortoPorto 4169-007Portugal

Neurodegenerative and neuropsychiatric diseases are increasingly affecting individuals’quality of life,thus increasing their cost to social and health *** diseases have overlapping mechanisms,such as oxidative stress,protein aggregation,neuroinflammation,neurotransmission impairment,mitochondrial dysfunction,and ***,there is no cure for neurodegenerative diseases,and the available therapies have adverse effects and low *** neuropsychiatric disorders,such as depression,the current therapies are not adequate to one-third of the patients,the so-called treatmentresistant ***,searching for new treatments is *** plants appear as a strong alternative and complement towards new treatment protocols,as they have been used for health purposes for thousands of ***,the main goal of this review is to revisit the neuroprotective potential of some of the most predominant medicinal plants(and one fungus)used in traditional Chinese medicine(TCm),focusing on their proven mechanisms of action and their chemical compositions,to give clues on how they can be useful against neurodegeneration progression.

关键词： Neurodegeneration Alzheimer's disease Parkinson's disease Depression medicinal plants Oxidative stress Toxicology Clinicaltrials