检索结果-南通市图书馆

Patterns of climber distribution in temperate forests of the Americas

在线全文

学校读者我要写书评

暂无评论

Journal of Plant Ecology 2016年第6期9卷 724-733页

作者： Annik Schnitzler Javier Amigo Brack Hale christophe Schnitzler Laboratoire Interdisciplinaire des Environnements Continentaux(LIEC) UMR 7360 Universitéde LorraineMetzFrance Laboratorio de Botánica Facultad de FarmaciaUniversidad de Santiago de CompostelaA CoruñaSpain Franklin University Switzerland SorengoSwitzerland Facultédes Sciences du Sport UnistraUniversitéde StrasbourgStrasbourgFrance

Aims and Methods We propose a standard protocol at the landscape to continental scale for examining to what extent the range of ecological conditions found in temperate latitudes explains the variations in climber species richness and *** protocol was tested in forests of the two *** data set included 151 climber *** selected four categorical traits and grouped these species into six clusters with regard to these *** records of American forests were first gathered into alliances,second combined with bioclimatic indices(rainfall,temperature,continentality).We obtained a total of 59 vegetational units in which we calculated values of climber species richness and proportion of *** units were ultimately gathered into five forest formations(characterized by leaf longevity).Wetlands and uplands were considered *** Findings Our results emphasize clear trends in large-scale patterns of climber distribution,independently of *** species richness(in particular woody climbers)peaks in moist and warm upland forests with oceanic climates,and where conifers are *** flooded areas,climber richness is also very high and peaks in seasonally flooded large *** ecological conditions of frost,dryness or lack of nutrients,climber species richness,abundance and trait diversity decline,resulting in the dominance of small,twining and deciduous life traits.

关键词： American forest bioclimatic indices climber life traits standart protocol species richness

A high-resolution clay mineralogical record in the northern South China Sea since the Last Glacial Maximum,and its time series provenance analysis

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2010年第35期55卷 4058-4068页

作者： LIU ZhiFei LI XiaJing COLIN christophe GE HuangMin State Key Laboratory of Marine Geology Tongji University Shanghai 200092 China Laboratoire IDES UMR 8148 CNRS Universit~ de Paris XI Orsay 91405 France

High-resolution clay mineralogical analysis of Core MD05-2904 in the northern South China Sea(SCS) covering the period since the Last Glacial Maximum shows that illite(29%-48%),smectite(14%-45%),chlorite(17%-28%),and minor kaolinite(6%-14%) comprise the clay mineral assemblage,and that time series variation does not present glacial-interglacial *** analysis indicates three end-member sources:almost all smectite derives from Luzon,all kaolinite is sourced from the Pearl River,and illite and chlorite originate from both the Pearl River and *** comparing clay mineral compositions in surface sediments from the three major source areas and of the SCS,we reconstructed a time series of clay mineral contribution from the major provenances to the northern slope of the SCS using the linear separation method for illite *** were three stages of provenance change.(1) During 24.1-17.5 ka BP,contributions from Taiwan and Luzon were similar(30%-40%),while that from the Pearl River was only 25%.(2) During 17.5-14.0 ka BP,the contribution from Luzon decreased rapidly to 20%-25%,while that from Taiwan increased to 35% from an average of 25% at 18 ka BP,and that from the Pearl River increased largely to 40%.(3) During the Holocene,differences in contributions from the three major provenances increased:the contribution from Luzon increased slightly and then remained at 27%-35%,that from Taiwan increased rapidly and then remained at 55%-60%,and that from the Pearl River decreased to 15%.The change in clay mineral contributions from different provenances is influenced mainly by clay mineral production,monsoon rainfall denudation,oceanic current transport,and sea-level change.

关键词：粘土矿物南海北部时间序列高分辨率中国海末次盛冰期 Sea 珠江源

A high-order SPH method by introducing inverse kernels

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2017年第1期30卷 1-14页

作者： Fang Le Marongiu Jean christophe Leduc Julien Amicarelli Andrea Caro Joёlleb LMP Ecole centrale de Pekin Beihang University Co-Innovation Center for Advanced Aero-Engine 100083 Beijing China LMFA Ecole centrale de Lyon 69130 Ecully BP 163 France Laboratoire International Associe Beihang University 100083 Beijing China ANDRITZ HYDRO AG Rue des Deux-Gares 6 1800 Vevey Switzerland

The smoothed particle hydrodynamics（SPH） method is usually expected to be an efficient numerical tool for calculating the fluid-structure interactions in compressors; however, an endogenetic restriction is the problem of low-order consistency. A high-order SPH method by introducing inverse kernels, which is quite easy to be implemented but efficient, is proposed for solving this restriction. The basic inverse method and the special treatment near boundary are introduced with also the discussion of the combination of the Least-Square（LS） and Moving-Least-Square（MLS） methods. Then detailed analysis in spectral space is presented for people to better understand this method. Finally we show three test examples to verify the method behavior.

关键词： Consistency High-order method Inverse method Numerical dissipation Numerical instability Smoothed particle hydrodynamics

Genetic algorithm-based multiple moving target reaching using a fleet of sailboats

在线全文

学校读者我要写书评

暂无评论

IET Cyber-Systems and Robotics 2019年第3期1卷 93-100页

作者： Viel christophe Vaultier Ulysse Wan Jian Jaulin Luc School of Engineering Computing and MathematicsUniversity of PlymouthPlymouthDevonUK Lab STICC ENSTA BretagneBrestFrance

This study addresses the problem of Dynamic Travelling Salesman Problem for a multi-agent system using a fleet of sailboats.A genetic algorithm(GA)is proposed,which attributes to each agent a varying number of targets to be *** allows obtaining a suboptimal solution in the shortest time ***,this study adapts it to the specific problem involving a fleet of sailboats,which is a challenging task with comparison to autonomous underwater vehicles or motorised vehicles in terms of the *** motors can be flexibly controlled while sailboat movements are constrained by available wind direction and *** the method takes into account wind conditions at various locations of the *** results demonstrate the effectiveness of the proposed approach.

关键词： agent flex algorithm

Codexas the Basis for National Standards and International Harmonization

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Biomedical and Environmental Sciences 2001年第Z1期 137-144页

作者： KRAISID,christophe LEPRTRE Director FoodandNutritionDivisionTONTISIRIN AssociateProfessionalOfficer(FoodStandards) JointFAO/WHOFoodStandardsProgramme!FoodandNutritionDivision FoodandAgricultureOrganizationoftheUnitedNations(FAO) Rome Italy

Chaos in DNA evolution

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

International Journal of Biomathematics 2016年第5期9卷 199-215页

作者： Jacques M. Bahi christophe Guyeux Antoine Perasso Institut FEMTO-ST Universitg Bourgogne Franche-Comtd 25000 Besancon France UMR Chrono-Environnement Universite Bourgogne Franche-Comte 25000 Besancon France

In this paper, we explain why the chaotic mutation （CM） model of J. M. Bahi and C. Michel （2008） simulates the genes mutations over time with good accuracy. It is firstly shown that the CM model is a truly chaotic one, as it is defined by Devaney. Then, it is established that mutations occurring in genes mutations have indeed a same chaotic dynamic, thus making relevant the use of chaotic models for genomes evolution. Transposition and inversion dynamics are finally investigated.

关键词： Genomes evolution models mutations inversions transpositions mathema- tical topology Devaney's chaos.

Representation of A15 composition and T_C in internal-Sn Nb_3Sn superconducting strands

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(Technological Sciences) 2010年第11期53卷 3020-3026页

作者： Andre SULPICE Jean-Louis SOUBEYROUX christophe VERWAERDE Gia Ky HOANG NEEL/CNRS-UJF ALSTOM 3 bis avenue des 3 Chenes 90018 Belfort France

Four sets of mono-element (ME) and two kinds of multifilament (MF) internal-Sn Nb3Sn superconducting strands were designed and fabricated through RRP method in which different compoment ratios, various composite configurations and some third element alloying were arranged. All the strand samples underwent a 210°C/50 h + 340°C/25 h thermal duration for Cu-Sn alloying. After that A15 phase formation heat treatment (HT) was applied for which the ME samples were chosen at three reaction temperatures of 675°C, 700°C and 725°C for 100 h and 200 h while the MF samples at four temperatures of 650°C, 675°C, 700°C and 725°C for 128 h and 200 h. The heat-treated samples were examined for A15 phase composition distribution by X-ray EDS. SQUID magnetization measurement was used to determine critical temperature TC. The obtained results demonstrate that for fully-reacted internal-Sn Nb3Sn superconductors the A15 phase composition and the intrinsic property TC are determined by the diffusion and solid state reaction mechanism and are independent of the factors including HT temperature, strand composite component and configuration arrangement, and the third element addition within the experimental range.

关键词： internal-Sn Nb3Sn strands A15 phase composition phase formation heat treatment composite configuration and design third element alloying

A Two-Step Algorithm to Estimate Variable Importance for Multi-State Data:An Application to COVID-19

在线全文

学校读者我要写书评

暂无评论

Computer Modeling in Engineering & Sciences 2023年第6期135卷 2047-2064页

作者： Behnaz Alafchi Leili Tapak Hassan Doosti christophe Chesneau Ghodratollah Roshanaei Department of Biostatistics School of Public HealthModeling of Noncommunicable Diseases Research CenterHamadan University of Medical SciencesHamadanIran School of Mathematical and Physical Sciences Macquarie UniversitySydneyAustralia Department of Mathematics LMNOUniversity of Caen-NormandieCaenFrance

Survival data with amulti-state structure are frequently observed in follow-up *** analytic approach based on a multi-state model(MSM)should be used in longitudinal health studies in which a patient experiences a sequence of clinical progression *** main objective in the MSM framework is variable selection,where attempts are made to identify the risk factors associated with the transition hazard rates or probabilities of disease *** usual variable selection methods,including stepwise and penalized methods,do not provide information about the importance of *** this context,we present a two-step algorithm to evaluate the importance of variables formulti-state *** differentmachine learning approaches(randomforest,gradient boosting,and neural network)as themost widely usedmethods are considered to estimate the variable importance in order to identify the factors affecting disease progression and rank these factors according to their *** performance of our proposed methods is validated by simulation and applied to the COVID-19 data *** results revealed that the proposed two-stage method has promising performance for estimating variable importance.

关键词： Multi-state data deviance residual martingale residual gradient boosting randomforest neural network variable importance variable selection

Reduced-particle size wheat bran and endoxylanase supplementation in broiler feed affect arabinoxylan hydrolysis and fermentation with broiler age differently

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Animal Nutrition 2023年第1期12卷 308-320页

作者： An Bautil Michael R.Bedford Johan Buyse christophe M.Courtin Laboratory of Food Chemistry and Biochemistry Department of Microbial and Molecular Systems(M2S)KU LeuvenLeuven3001Belgium AB Vista MarlboroughWiltshire SN84ANUnited Kingdom Laboratory of Livestock Physiology Department of BiosystemsKU LeuvenLeuven3001Belgium

Since the caecal microbiota of young broilers are not yet able to ferment the dietary fibre(DF)fraction of the feed to a large extent,increasing the accessibility of DF substrates along the gastrointestinal tract is crucial to benefit from the health stimulating metabolic end-products(*** acid)generated upon microbial DF ***,the present study aimed to evaluate the potential of reduced-particle size wheat bran(RPS-WB)and endoxylanases as feed additives to stimulate arabinoxylan(AX)hydrolysis and fermentation along the hindgut of young *** this end,RPS-WB and endoxylanase supplementation were evaluated in a 2×2 factorial design using a total of 256 male 1-d-old chicks(Ross 308).Broilers were assigned to 4 dietary treatments:a basal wheat-based diet with(1)no feed additives(control,CTRL),(2)an endoxylanase(XYL;Econase XT 25 at 0.10 g/kg diet),(3)1%wheat bran with an average reduced particle size of 297μm(RPS-WB)and(4)an endoxylanase and 1%RPS-WB(RPS-WB+XYL).Each dietary treatment was replicated 8 times and on d 10 and 28,respectively,24 and 16 broilers per treatment group were euthanised to analyse AX degradation,short-chain fatty acid production and digesta viscosity in the ileum and *** receiving XYL in their diet showed increased AX solubilisation and fermentation at both d 10 and 28 compared to the CTRL group(P<0.05).Adding RPS-WB to the diet stimulated wheat AX utilisation by the primary AX degraders in the caecum at 10 d of age compared to the CTRL group,as observed by the high AX digestibility coefficient for the RPS-WB supplemented group at this young age(P<0.05).At 28 d,RPS-WB supplementation lowered body-weight gains but increased butyric acid concentrations compared to the XYL and CTRL group(P<0.05).Although no synergistic effect for RPS-WB+XYL broilers was observed for AX hydrolysis and fermentation,these findings suggest that both additives can raise a dual benefit to the broiler as a butyrogenic effect and im

关键词： Broiler chicken Wheat bran Particle size reduction Xylanase Arabinoxylan fermentation