检索结果-南通市图书馆

Cameroon Climate Predictions Using the SARIMA-LSTM Machine Learning Model: Adjustment of a Climate Model for the Sudano-Sahelian Zone of Cameroon

引用

Open Journal of Statistics 2024年第3期14卷 394-411页

作者： Joseph Armathé Amougou Isidore Séraphin Ngongo Patrick Forghab Mbomba Romain Armand Soleil Batha paul Ghislain Poum Bimbar Dpartement de Gographie Universit de Yaound 1 Yaound Cameroon Observatoire National sur les Changements Climatiques (ONACC) Yaound Cameroon laboratoire dAnalyse et Modlisation Multidisciplinaire Statistique (SAMM) Universit de Paris 1 Panthon Sorbonne Paris France Ecole Nationale Suprieure Polytechnique de Yaound 1 Yaound Cameroon Dpartement de Mathmatiques Ecole Normale Suprieure de Yaound Yaound Cameroon Dpartement dInformatique Universit de Yaound 1 Yaound Cameroon

It is acknowledged today within the scientific community that two types of actions must be considered to limit global warming: mitigation actions by reducing GHG emissions, to contain the rate of global warming, and adaptation actions to adapt societies to Climate Change, to limit losses and damages [1] [2]. As far as adaptation actions are concerned, numerical simulation, due to its results, its costs which require less investment than tests carried out on complex mechanical structures, and its implementation facilities, appears to be a major step in the design and prediction of complex mechanical systems. However, despite the quality of the results obtained, biases and inaccuracies related to the structure of the models do exist. Therefore, there is a need to validate the results of this SARIMA-LSTM-digital learning model adjusted by a matching approach, “calculating-test”, in order to assess the quality of the results and the performance of the model. The methodology consists of exploiting two climatic databases (temperature and precipitation), one of which is in-situ and the other spatial, all derived from grid points. Data from the dot grids are processed and stored in specific formats and, through machine learning approaches, complex mathematical equations are worked out and interconnections within the climate system established. Through this mathematical approach, it is possible to predict the future climate of the Sudano-Sahelian zone of Cameroon and to propose adaptation strategies.

关键词： Adjustment Calibration Climate Sudano-Sahelian Zone Numerical Model

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

A SEM-based method to determine the mineralogical composition and the particle size distribution of suspended sediment

引用

International Journal of Sediment Research 2019年第2期34卷 85-94页

作者： Sylvain Pinet Bruno Lartiges Jean-Michel Martinez Sylvain Ouillonc University of Toulouse (paul Sabatier) Geosciences Environment ToulouseCNRS(Centre National de la Recherche Scientifique)IRD(Institut de Recherche pour le Développement) Instituto de Geosciencias Universidade de BrasiliaCampus Universitario Darcy RibeiroICC Centro University of Toulouse LEGOS(Laboratoire d'Etudes en Géophysique et Océanographie Spatiales)

A robust method for characterizing the mineralogy of suspended sediment in continental rivers is *** encompasses 3 steps:the filtration of a few milliliters of water,measurements of X-ray energy dispersive spectra using Scanning Electron Microscopy(SEM),and robust machine learning tools of *** method is applied to suspended particles collected from various Amazonian rivers.A total of more than 204,000 particles were analyzed by SEM-EDXS(Energy Dispersive X-ray Spectroscopy),*** 15,700 particles per sampling station,which lead to the identification of 15 distinct groups of mineralogical *** size distribution of particles collected on the filters was derived from the SEM micrographs taken in the backscattered electron imaging mode and analyzed with ImageJ *** determination of the main mineralogical groups composing the bulk sediment associated with physical parameters such as particle size distribution or aspect ratio allows a precise characterization of the load of the terrigenous particles in rivers or *** the case of the Amazonian rivers investigated,the results show that the identified mineralogies are consistent with previous studies as well as between the different samples *** method enabled the evolution of grain size distribution from fine to coarse material to be described in the water *** about hydrodynamic sorting of mineral particles in the water column are also briefly *** proposed method appears well suited for intensive routine monitoring of suspended sediment in river systems.

关键词： Mineralogy Scanning Electron Microscopy Suspended sediment Machine learning Particle size distribution

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Infrared-active phonons in one-dimensional materials and their spectroscopic signatures

引用

npj Computational Materials 2023年第1期9卷 331-337页

作者： Norma Rivano Nicola Marzari Thibault Sohier Theory and Simulations of Materials(THEOS) École Polytechnique Fédérale de LausanneCH-1015 LausanneSwitzerland National Centre for Computational Design and Discovery of Novel Materials(MARVEL) École Polytechnique Fédérale de LausanneCH-1015 LausanneSwitzerland Laboratory for Materials Simulations Paul Scherrer Institut5232 Villigen PSISwitzerland laboratoire Charles Coulomb(L2C) Universitéde MontpellierCNRSMontpellierFrance

Dimensionality provides a clear fingerprint on the dispersion of infrared-active,polar-optical *** these phonons,the local dipoles parametrized by the Born effective charges drive the LO-TO splitting of bulk materials;this splitting actually breaks down in two-dimensional ***,we develop the theory for one-dimensional(1D)systems—nanowires,nanotubes,and atomic and polymeric *** an analytical model with the implementation of density-functional perturbation theory in 1D boundary conditions,we show that the dielectric splitting in the dispersion relations collapses as x^(2) log(x)at the zone *** dielectric properties and the radius of the 1D materials are linked by the present work to these red shifts,opening infrared and Raman characterization avenues.

关键词： dimensional splitting dielectric

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Evolution of a Holocene banner bank controlled by morphodynamics and structural setting of a macrotidal coast: Saint-Brieuc Bay (NW-Europe)

引用

Geoscience Frontiers 2021年第5期12卷 166-181页

作者： Kalil Traoréa David Menier Erwan Gensac Pascal Le Roy Clément Lambert paul Bessin Kevin Pedoja Anne Duperret Romain Le Gall laboratoire Géoscience Océan UMR 6538CNRSUniversitéBretagne SudCampus de Tohannic56000 VannesFrance laboratoire Géoscience Océan UMR 6538CNRSIUEMUniversitéBretagne Occidentale29280 PlouzanéFrance laboratoire de Planétologie et Géodynamique UMR 6112CNRSLe Mans UniversitéAvenue Olivier Messiaen72085 Le Mans CEDEX 9France laboratoire Morphodynamique Continentale et Côtière UMR 6143CNRSUniversitéCaen Normandiecampus 12-4Rue des Tilleuls14000 Caen cedexFrance laboratoire Ondes et Milieux Complexes UMR 6294CNRSUniversitéLe Havre Normandie53 rue de PronyCS8054076058 Le Havre cedexFrance

The morphology and internal structure of the Horaine Bank(Bay of Saint-Brieuc,NW France)are described based on multibeam echosounder and high-resolution seismic datasets coupled with vibro-core *** Horaine Bank shows large-scale bedforms in the lee of a submerged rocky shoal,which allowed defining it as a Banner *** internal structure of the sandbank reveals four seismic units(U1-U4)on a Cambrian basement(U0).The basal unit U1 is interpreted as reworked lowstand fluvial sediments those infilled micro incised valleys during a rise in sea *** unit is overlain by paleo-coastal barrier sand-spit(U2)whose development was controlled by swell in the context of a rapid rise in sea *** successive prograding unit(U3)is interpreted as flooding deposits in continuity with unit *** unit U4 is characterized by oblique reflectors oriented in two opposite *** last unit,dated post 3500 yr BP,corresponds to migrating dunes superimposed on the bank and observable in the high-resolution bathymetric *** strong correlation between tidal currents and the apparent clockwise migration of dune crests suggests the presence of a tidal gyre controlling the present-day dynamics of most of the Horaine bank *** study proposes a new model for the construction of banner banks characterized by the gradual transition of a sand spit to a banner bank during marine transgression and ensuing hydrodynamic variability.

关键词： Sand banks Banner bank Holocene climate Geomorphology Sea level rise Tidal gyre

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A GENERALIZED PENALTY METHOD FOR DIFFERENTIAL VARIATIONAL-HEMIVARIATIONAL INEQUALITIES

引用

Acta Mathematica Scientia 2022年第1期42卷 247-264页

作者： Liang LU Lijie LI Mircea SOFONEA Guangxi Key Laboratory of Cross-border E-commerce Intelligent Information Processing Guangxi University of Finance and EconomicsNanning 530003China Guangxi Colleges and Universities Key Laboratory of Complex System Optimization and Big Data Processing Yulin Normal UniversityYulin 537000China laboratoire de Mathématiques et Physique Universitéde Perpignan Via Domitia52 Avenue Paul Alduy66860 PerpignanFrance

We consider a differential variational-hemivariational inequality with constraints,in the framework of reflexive Banach *** existence of a unique mild solution of the inequality,together with its stability,was proved in[1].Here,we complete these results with existence,uniqueness and convergence results for an associated penalty-type *** this end,we construct a sequence of perturbed differential variational-hemivariational inequalities governed by perturbed sets of constraints and penalty *** prove the unique solvability of each perturbed inequality as well as the convergence of its solution to the solution of the original ***,we consider a mathematical model which describes the equilibrium of a viscoelastic rod in unilateral *** weak formulation of the model is in a form of a differential variational-hemivariational inequality in which the unknowns are the displacement field and the history of the *** apply our abstract penalty method in the study of this inequality and provide the corresponding mechanical interpretations.

关键词： differential variational-hemivariational inequality generalized penalty method Mosco convergence viscoelastic rod unilateral constraint

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Livestock induces strong spatial heterogeneity of soil CO2, N2O and CH4 emissions within a semi-arid sylvo-pastoral landscape in West Africa

引用

Journal of Arid Land 2017年第2期9卷 210-221页

作者： Mohamed H ASSOUMA Dominique SERCA Frederic GUERIN Vincent BLANFORT Philippe LECOMTE Ibra TOURE Alexandre ICKOWICZ Raphael J MANLAY Martial BERNOU Jonathan VAYSSIERES CIRAD-UMR Selmet Campus International Baillarguet Montpellier 34398 France DP PPZS ISRA-LNERV BP 2057 Dakar Hann Senegal laboratoire d'Aerologie-OMP Universite Paul Sabatier 14 Avenue Edouard Belin Toulouse 31400 France Geosciences Environnement Toulouse UMR 5563 & UR 234 IRD Universite Paul Sabatier Avenue Edouard Belin 14 Toulouse 31400 France CILSS 03 BP 7049 Ouagadougou Burkina Faso AgroParisTech-UMR Eco&Sols 2 place Viala Montpellier SupAgro Montpellier 34060 France IRD-UMR Eco&Sols 2 place Viala Montpellier SupAgro Montpellier 34060 France

Greenhouse gas （GHG） emissions from the surface soils and surface water receiving animal excreta may be important components of the GHG balance of terrestrial ecosystems, but the associated processes are poorly documented in tropical environments, especially in tropical arid and semi-arid areas. A typical sylvo-pastoral landscape in the semi-arid zone of Senegal, West Africa, was investigated in this study. The study area （706 km2 of managed pastoral land） was a circular zone with a radius of 15 km centered on a borehole used to water livestock. The landscape supports a stocking rate ranging from 0.11 to 0.39 tropical livestock units per hectare depending on the seasonal movements of the livestock. Six landscape units were investigated （land in the vicinity of the borehole, natural ponds, natural rangelands, forest plantations, settlements, and enclosed plots）. Carbon dioxide （CO2）, nitrous oxide （N2O） and methane （CH4） fluxes were measured with static chambers set up at 13 sites covering the six landscape units, and the 13 sites are assumed to be representative of the spatial heterogeneity of the emissions. A total of 216 fluxes were measured during the one-year study period （May 2014 to April 2015）. At the landscape level, soils and surface water emitted an average 19.8 t C-CO2 eq/（hm2.a）（CO2： 82%, N2O： 15%, and CH4： 3%）, but detailed results revealed notable spatial heterogeneity of GHG emissions. CO2 fluxes ranged from 1148.2 （±91.6） mg/（m2.d） in rangelands to 97,980.2 （±4,861.7） mg/（m2.d） in surface water in the vicinity of the borehole. N2O fluxes ranged from 0.6 （±0.1） mg/（m2.d） in forest plantations to 22.6 （±10.8） mg/（m2.d） in the vicinity of the borehole. CH4 fluxes ranged from -3.2 （±0.3） mg/（m2.d） in forest plantations to 8788.5 （±2295.9） mg/（m2.d） from surface water in the vicinity of the borehole. This study identified GHG emission ＂hot spots＂ in the landscape. Emissions from the surface soils were significantly higher in the landscape units most freq

关键词： greenhouse gases soil surface water livestock landscape Senegal

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Accumulation of Flavonoids in an ntra ntrb Mutant Leads to Tolerance to UV-C

引用

Molecular Plant 2009年第2期2卷 249-258页

作者： Talaat Bashandy Ludivine Taconnat Jean-Pierre Renou Yves Meyer Jean-Philippe Reichheld laboratoire Genome et Developpement des Plantes Universite de Perpignan UMR CNRS 5096 52 avenue Paul Alduy 66860 Perpignan France Unite de Recherche en Genomique Vegetale 91057 Evry cedex France

NADPH-dependent thioredoxin reductases （NTRs） are key regulatory enzymes determining the redox state of thioredoxins. There are two genes encoding NTRs （NTRA and NTRB） in the Arabidopsis genome, each encoding a cytosolic and a mitochondrial isoform. A double ntra ntrb mutant has recently been characterized and shows slower plant growth, slightly wrinkled seeds and a remarkable hypersensitivity to buthionine sulfoximine （BSO）, a specific inhibitor of gluta- thione biosynthesis. In this paper, we demonstrate that this mutant also accumulates higher level of flavonoids. Analysis of transcriptome data showed that several genes of the flavonoid pathway are overexpressed in the ntra ntrb mutant. Accumulation of flavonoids is generally considered a hallmark of plant stress. Nevertheless, no elevation of the expression of genes encoding ROS-detoxification enzymes was observed, suggesting that the ntra ntrb plants do not suffer from oxidative disease. Another hypothesis suggests that flavonoids are specifically synthesized in the ntra ntrb mutant in order to rescue the inactivation of NTR. To test this, the ntra ntrb mutant was crossed with transparent testa 4 （tt4） plants with a mutation in the gene encoding the first enzyme in flavonoid biosynthesis. As ntra ntrb plants are more resistant to UV-C treatment than wild-type plants, this higher resistance was abolished in the ntra ntrb tt4 mutant, suggesting that accumulation of flavonoids in the ntra ntrb mutant protects plants against UV-light.

关键词： abiotic/environmental stress oxidative and photo-oxidative stress secondary metabolism - phenylpropanoidsand phenolics gene expression Arabidopsis.

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Influence of alkali mixed effect on the mixing enthalpy in 0.75B_2O_3-0.25[xNa_2O-(1-x)K_2O]glass system

引用

Chinese Chemical Letters 2008年第10期19卷 1252-1255页

作者： A.Kouyate A.P.Ahoussou A.Yapi D.Diabate J.Rogez A.Trokourey laboratoire de Chimie-Physique UFR-SSMTUniversité de Cocody22 BP 582 Abidjan 22Cote d'Ivoire Institut des Matériaux de Microélectroniquede Nanoscience de ProvenceIM2NPUMR 6242CNRSUniversité Paul CézanneMarseilleFaculté des Sciences et Techniques de St Jérme13397 Marseille Cedex 20France

The mixed alkali effect was investigated in the glass system 0.75B2O3-0.25[xNa2O-（1 -x）K20] through thermodynamic properties. The calorimetric measurements were performed in HF solution calorimetry at 298 K. The mixing enthalpy values show non-linear behaviour upon substitution of one alkali ion by another. This thermodynamic non-ideality is caused by the slight variations of distance between metallic cations, the macromolecular structure being unchanged. It can be explained, at least qualitatively, using electrolyte theory based on the Coulombic interactions of charged species originally developed by Debye and Hückel.

关键词： Alkali mixed effect Calorimetry Mixing enthalpy Coulombic interactions

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

UDNS or LES, That Is the Question

引用

Open Journal of Fluid Dynamics 2015年第4期5卷 339-352页

作者： Christoph Bosshard Michel O. Deville Abdelouahab Dehbi Emmanuel Leriche paul Scherrer Institut Laboratory for Thermal-Hydraulics (LTH) Villigen PSI Switzerland école Polytechnique Fédérale de Lausanne School of Engineering Lausanne Switzerland Université de Lille 1 Laboratoire de Mécanique Boulevard Paul Langevin Villeneuve d'Ascq Cedex France

In the framework of the spectral element method, a comparison is carried out on turbulent first-and second-order statistics generated by large eddy simulation (LES), under-resolved (UDNS) and fully resolved direct numerical simulation (DNS). The LES is based on classical models like the dynamic Smagorinsky approach or the approximate deconvolution method. Two test problems are solved: the lid-driven cubical cavity and the differentially heated cavity. With the DNS data as benchmark solutions, it is shown that the numerical results produced by the UDNS calculation are of the same accuracy, even in some cases of better quality, as the LES computations. The conclusion advocates the use of UDNS and calls for improvement of the available algorithms.

关键词： Spectral Element Method Under-Resolved Direct Numerical Simulation Large Eddy Simulation Lid-Driven Cavity Differentially Heated Cavity

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Neonatal Morbidity and Mortality at Hospital Saint Camille de Ouagadougou (HOSCO): A Study from 2017 to 2020

引用

Open Journal of Pediatrics 2024年第1期14卷 63-77页

作者： Nicaise Zagre Ines Kinda Abdoul Karim Ouattara paul Ouedraogo Théodora Mahoukèdè Zohoncon Caroline Yonaba Fla Koueta Jacques Simpore Hô pital Saint Camille de Ouagadougou (HOSCO) Ouagadougou Burkina Faso Faculté des Sciences de la Santé Université Saint Thomas d’Aquin (USTA) Ouagadougou Burkina Faso laboratoire de Biologie Moléculaire et de Génétique (LABIOGENE) Université Joseph KI-ZERBO Ouagadougou Burkina Faso Centre de Recherche Biomoléculaire Pietro Annigoni (CERBA) Ouagadougou Burkina Faso Faculté des Sciences de la Santé Université Joseph KI-ZERBO Ouagadougou Burkina Faso

Introduction: Neonatal pathology remains a real public health problem in developing countries. In Burkina Faso, this mortality has declined over the last ten years but remains below compared to the Sustainable Development Goals, which is 12 per 1000 living births at most by 2030. This study aims to identify specific causes of neonatal morbidity and mortality and will contribute to the implementation of preventive and curative measures aimed at reducing neonatal mortality at HOSCO. Method: This was a retrospective study using the records and database of newborns hospitalized from January 1srt, 2017 to December 31srt, 2020. Using logistic regression, the factors associated with mortality were determined. Results: During the study period, 3020 newborns were hospitalized. Most newborns (83.71%) were referred by a peripheral health facility. The average age at admission was 0.3 days ± 0.9 and the sex ratio was 1.2. Prematurity was the leading cause of hospitalization (61.13%) followed by neonatal infection (38.34%) and neonatal suffering (23.88%). The mortality rate was 40.6% with 82.71% cases of death in the early neonatal period. The main causes of death were low birth weight (47.39%), respiratory distress (18.76%), neonatal suffering (17.37%) and neonatal infection (13.87%). Home delivery, gestational age 36 weeks, number of PNC 4, concept of resuscitation, Apgar at the 5th minute 7, birth weight 2000 g and >4000 g, respiratory distress, hypothermia, neurological disorders were factors associated with deaths. Conclusion: Neonatal mortality is influenced by both maternal and fetal factors and many of them are preventable.

关键词： Morbidity Mortality Newborns Neonatology HOSCO

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：