检索结果-南通市图书馆

Spatiotemporal patterns of burned areas,fire drivers,and fire probability across the equatorial Andes

Journal of Mountain Science 2021年第4期18卷 952-972页

作者： Xavier ZAPATA-RiOS Carmen LOPEZ-FABARA Abigail NAVARRETE Sandra torres-PAGUAY Miguel FLORES Department of Civil and Environmental Engineering Escuela Politecnica NacionalLadron de Guevara E11-253P.O.Box 17-01-2759QuitoEcuador Center for Research and Water Resources Studies(CIERHI) Escuela Politecnica NacionalLadron de Guevara E11-253P.O.Box 17-01-2759QuitoEcuador Faculty of Agricultural Sciences Universidad Central del EcuadorAv.UniversitariaP.O.Box 17-03-100QuitoEcuador Modeling Optimization and Inferential Statistics Group(MODES)Department of MathematicsEscuela Politecnica NacionalLadron de Guevara Ell-253P.O.Box 17-01-2759QuitoEcuador

Field-based fire studies in the equatorial Andes indicate that fires are strongly associated with biophysical and anthropogenic ***,fire controls and fire regimes at the regional scale remain ***,this paper describes spatial and temporal burned-area patterns,identifies biophysical and anthropogenic fire drivers,and quantifies fire probability across 6°of latitude and 3°of longitude in the equatorial *** spatial and temporal burned-area analysis was carried out based on 18 years(2001-2018)of the MCD64 A1 MODIS burned-area ***,topography,vegetation,and anthropogenic variables were integrated in a logistic regression model to identify the significance of explanatory variables and determine fire occurrence probability.A total of 5779 fire events were registered during the 18 years of this study,located primarily along the western cordillera of the Andes and spreading from North to ***-eight percent of these fires took place within two fire hotspots located in the northwestern and southwestern corners of the study ***-nine percent occurred during the second part of the year,between June and *** largest density of fires was primarily located on herbaceous vegetation and *** show that mean monthly temperature,precipitation and NDVI during the prefire season,the location of land cover classes such as forest and agriculture,distance to roads and urban areas,slope,and aspect were the most important determinants of spatial and temporal fire *** logistic regression model achieved a good accuracy in predicting fire probability(80%).Probability was higher in the southwestern and northern corners of the study area,and lower towards the north in the western and eastern piedmonts of the *** analysis contributes to the understanding of fires in mountains within the *** results here presented have the potential to contribute to fire management and control in the regi

关键词： MODIS MCD64A1 Spectral vegetation indices Pre-fire season NDVI and precipitation Remote sensing

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

Fast preparation route to high-performances textured Sr-doped Ca_3Co_4O_9 thermoelectric materials through precursor powder modification

引用

Science China Materials 2019年第3期62卷 399-406页

作者： Miguel Angel torres Gustavo Garcia Idoia Urrutibeascoa Maria Antonieta Madre Juan Carlos Diez Andres Sotelo ICMA (CSIC-Universidad de Zaragoza) Centro Stirling S. Coop. Mondragon Unibertsitatea

This work presents a short and very efficient method to produce high performance textured Ca_3Co_4O_9 thermoelectric materials through initial powders modification. Microstructure has shown good grain orientation, and low porosity while slightly lower grain sizes were obtained in samples prepared from attrition milled powders. All samples show the high density of around 96% of the theoretical *** similar characteristics are reflected in, approximately,the same electrical resistivity and Seebeck coefficient values for both types of samples. However, in spite of similar power factor(PF) at low temperatures, it is slightly higher at high temperature for the attrition milled samples. On the other hand, the processing time reduction(from 38 to 2 h) when using attrition milled precursors, leads to lower mechanical properties in these samples. All these data clearly point out to the similar characteristics of both kinds of samples, with a drastic processing time decrease when using attrition milled precursors, which is of the main economic importance when considering their industrial production.

关键词： ceramics oxides hot-pressing electrical properties power factor

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

Frequency Response Optimization of Dual Depletion InGaAs/InP PIN Photodiodes

引用

Photonic Sensors 2016年第1期6卷 63-70页

作者： J. M. torres PEREIRA Joao Paulo N. torres Instituto de Telecomunicacoes Instituto Superior Tecnico-Universidade de Lisboa Lisboa Portugal

The frequency response of a dual depletion p-i-n （PIN） photodiode structure is investigated. It is assumed that the light is incident on the N side and the drift region is located between the N contact and the absorption region. The numerical model takes into account the transit time and the capacitive effects and is applied to photodiodes with non-uniform illumination and linear electric field profile. With an adequate choice of the device＇s structural parameters, dual depletion photodiodes can have larger bandwidths than the conventional PIN devices.

关键词： PIN photodiodes dual depletion frequency response modeling

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

Algorithms for Computing Some Invariants for Discrete Knots

引用

Applied Mathematics 2013年第11期4卷 1526-1530页

作者： Gabriela Hinojosa David torres Rogelio Valdez Facultad de Ciencias Universidad Autónoma del Estado de Morelos Cuernavaca México

Given a cubic knot K, there exists a projection? of the Euclidean space R3?onto a suitable plane ?such that p(K) is a knot diagram and it can be described in a discrete way as a cycle permutation. Using this fact, we develop an algorithm for computing some invariants for K: its fundamental group, the genus of its Seifert surface and its Jones polynomial.

关键词： Cubic Knots Discrete Knots Algorithms

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

Dynamically generated N* resonances from the interaction of two mesons and a baryon

引用

Chinese Physics C 2009年第12期33卷 1302-1306页

作者： A. Martínez torres K. P. Khemchandani E. Oset Departamento de Física Teórica and IFIC Centro Mixto Universidad de Valencia-CSIC Institutos de Investigación de Paterna Aptdo. 22085 46071 Valencia Spain Centro de Física Teórica Departamento de Física Universidade de Coimbra P-3004-516 Coimbra Portugal

We have studied the ππN system and coupled channels by using of the Faddeev equations and two N* and one △ states, all of them with JP =1/2+, have been found in the formalism as dynamically generated states. In addition, signatures for a new N* resonance with JP =1/2+ are found around an energy of 1920 MeV in the three-body center of mass system.

关键词： Few-body systems chiral dynamics S = 0 resonances

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

A Data Mining Approach to Detecting Bias and Favoritism in Public Procurement

引用

Intelligent Automation & Soft Computing 2023年第6期36卷 3501-3516页

作者： Yeferson torres-Berru Vivian F.Lopez-Batista Lorena Conde Zhingre University of Salamanca Salamanca37008Spain Instituto Tecnológico Superior Sudamericano Loja1101608Ecuador Universidad Internacional del Ecuador Loja1101608Ecuador

In a public procurement process,corruption can occur at each stage,favoring a participant with a previous agreement,which can result in over-pricing and purchases of substandard products,as well as gender *** paper’s aim is to detect biased purchases using a Spanish Language corpus,ana-lyzing text from the questions and answers registry platform by applicants in a public procurement process in ***,gender bias is detected,pro-moting both men and women to participate under the same *** order to detect gender bias and favoritism towards certain providers by contracting enti-ties,the study proposes a unique hybrid model that combines Artificial Intelli-gence algorithms and Natural Language Processing(NLP).In the experimental work,303,076 public procurement processes have been analyzed over 10 years(since 2010)with 1,009,739 questions and answers to suppliers and public insti-tutions in each *** bias and favoritism were analyzed using a Word2-vec model with word embedding,as well as sentiment analysis of the questions and answers using the VADER *** 32%of cases(96,984 answers),there was favoritism or gender bias as evidenced by responses from contracting *** proposed model provides accuracy rates of 88% for detecting favor-itism,and 90%for detecting gender *** one-third of the procure-ment processes carried out by the state have indications of corruption and *** Latin America,government corruption is one of the most significant challenges,making the resulting classifier useful for detecting bias and favoritism in public procurement processes.

关键词： Favoritism bias natural language processing Word2vec sentiment analysis word embeddings

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

Ventricular repolarization markers for predicting malignant arrhythmias in clinical practice

引用

World Journal of Clinical Cases 2015年第8期3卷 705-720页

作者： Yaniel Castro-torres Raimundo Carmona-Puerta Richard E Katholi Facultad de Medicina Universidad de Ciencias Médicas Dr.Serafín Ruiz de Zárate Ruiz Cardiocentro Ernesto Che Guevara Southern Illinois University School of Medicine and Prairie Cardiovascular Consultants

Malignant cardiac arrhythmias which result in sudden cardiac death may be present in individuals apparently healthy or be associated with other medical conditions. The way to predict their appearance represents a challenge for the medical community due to the tragic outcomes in most cases. In the last two decades some ventricular repolarization(VR) markers have been found to be useful to predict malignant cardiac arrhythmias in several clinical conditions. The corrected QT, QT dispersion, Tpeak-Tend, Tpeak-Tend dispersion and Tp-e/QT have been studied and implemented in clinical practice for this purpose. These markers are obtained from 12 lead surface electrocardiogram. In this review we discuss how these markers have demonstrated to be effective to predict malignant arrhythmias in medical conditions such as long and short QT syndromes, Brugada syndrome, early repolarization syndrome, acute myocardial ischemia, heart failure, hypertension, diabetes mellitus, obesity and highly trained athletes. Also the main pathophysiological mechanisms that explain the arrhythmogenic predisposition in these diseases and the basis for the VR markers are discussed. However, the same results have not been found in all conditions. Further studies are needed to reach a global consensus in order to incorporate these VR parameters in risk stratification of these patients.

关键词： Electrocardiographic predictor Ventricular repolarization markers Ventricular fibrillation Sudden cardiac death QT interval Corrected QT interval QT dispersion Tpeak-Tend interval Tpeak-Tend QT ratio

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

Fetal vs adult mesenchymal stem cells achieve greater gene expression, but less osteoinduction

引用

World Journal of Stem Cells 2015年第1期7卷 223-234页

作者： Juan E Santiago-torres Rebecca Lovasz Alicia L Bertone Comparative Orthopedic Research Laboratory Department of Veterinary Clinical Sciences College of Veterinary Medicine The Ohio State University Columbus OH 43210 United States College of Medicine The Ohio State University Columbus OH 43210 United States

AIM: To investigate adenoviral transduction in mesenchymal stem cells(MSCs) and effects on stemness in vitro and function as a cell therapy in ***: Bone marrow-derived adult and fetal MSC were isolated from an equine source and expanded in monolayer tissue culture. Polyethylenimine(PEI)-mediated transfection of pc DNA3-e GFP or adenoviral transduction of green fluorescent protein(GFP) was evaluated in fetal MSCs. Adenoviral-mediated transduction was chosen for subsequent experiments. All experiments were carried out at least in triplicate unless otherwise noted. Outcome assessment was obtained by flow cytometry or immunohystochemistry and included transduction efficiency, cell viability, stemness(i.e., cell proliferation, osteogenic and chondrogenic cell differentiation), and quantification of GFP expression. Fetal and adult MSCs were then transduced with an adenoviral vector containing the gene for the bone morphogenic protein 2(BMP2). In vitro BMP2 expression was assessed by enzyme linked immunosorbent assay. In addition, MSC-mediated gene delivery of BMP2 was evaluated in vivo in an osteoinduction nude mouse quadriceps model. New bone formation was evaluated by microradiography and ***: PEI provided greater transfection and viability in fetal MSCs than other commercial chemical reagents. Adenoviral transduction efficiency was superior to PEI-mediated transfection of GFP in fetal MSCs(81.3% ± 1.3% vs 35.0% ± 1.6%, P < 0.05) and was similar in adult MSCs(78.1% ± 1.9%). Adenoviral transduction provided significantly greater expression of GFP in fetal than adult MSCs(7.4 ± 0.1 vs 4.4 ± 0.3 millions of mean fluorescence intensity units, P < 0.01) as well as significantly greater in vitro BMP2 expression(0.16 pg/cell-day vs 0.10 pg/cell-day, P < 0.01). Fraction of fetal MSC GFP positive cells decreased significantly faster than adult MSCs(1.15% ± 0.05% vs 11.4% ± 2.1% GFP positive at 2 wk post-transduction, P < 0.05). Cell proliferation and osteo

关键词： Mesenchymal stem cells Biomarkers Next generation sequencing Diagnostic tool Tumor-initiating cells

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

Hydrothermal synthesis of pyrrhotite(Fex-1S) nanoplates and their antibacterial, cytotoxic activity study

引用

Progress in Natural Science:Materials International 2018年第4期28卷 447-455页

作者： Liliana Argueta-Figueroa Nayely torres-Gómez René García-Contreras A.R.Vilchis-Nestor O.Martínez-Alvarez L.S.Acosta-torres M.C.Arenas-Arrocena Laboratorio de Investigación Interdisciplinaria área de Nanoestructuras y Biomateriales Escuela Nacional de Estudios Superiores Unidad León Universidad Nacional Autónoma de México Centro Conjunto de Investigación en Química Sustentable (CCIQS) UEAMex-UNAM Departamento de Ingeniería en Energía Universidad Politécnica de Guanajuato

The aim of this study was to synthesize and characterize Fex-1S 2D-nanostructures with pyrrhotite phase,as well as to explore their biological(antibacterial and cytotoxic)properties,namely the expression of reactive oxygen species(ROS)in the exposure of cells and *** on hydrothermal synthesis,the characterization of asprepared 2D-nanostructures was performed by XRD,SEM,EDS,and TEM,in which the single-crystalline pyrrhotite phased Fex-1S nanoplate morphology was *** antibacterial activities of Fex-1S nanoplates against human pathogenic strains such as Staphylococcus aureus,Escherichia coli,and Enterococcus faecalis were *** inhibitory concentration(MIC)and minimum bactericidal concentration(MBC)were determined following the broth microdilution *** and expression of intracellular ROS of pyrrhotite nanoplates on Human Gingival Fibroblast(HGF),Human Pulp Cells(HPC)and Human Osteoblast(HBC)were *** viability was determined by the MTT *** experiments were performed of three independent experiments and data were analyzed by Kruskal-Wallis and Mann-Whitney tests,also Pearson′s Correlation was *** nanoplates exhibited good bactericidal *** types of cells tested showed slight *** was found that intracellular ROS is produced when cells and bacteria tested are exposed to pyrrhotite nanoplates in presence of both air and peroxide *** production levels were higher in the bacteria than the cells exposed to these nanoplates.

关键词： Hydrothermal synthesis Iron sulfide nanoplates Minimal inhibitory concentration Antibacterial effect Cytotoxicity assay

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

In vitro antioxidant,antilipoxygenase and antimicrobial activities of extracts from seven climbing plants belonging to the Bignoniaceae

引用

Journal of Integrative Medicine 2018年第4期16卷 255-262页

作者： Carola Analla torres Cristina Marisel Perez Zamora Maria Beatriz Nunez Ana Maria Gonzalez Laboratory of Microbiology and Pharmaceutical Technology Department of Basic and Applied SciencesNational University of Chaco AustralPresidencia Roque Saenz Pena 3700ChacoArgentina National Council for Scientific and Technical Research(CONICET) Godoy Cruz 2290Buenos Aires C1425FQBArgentina Institute of Botany of the Northeast(IBONE-CONICET) Sargento Juan Bautista Cabral 2131CorrientesArgentina

Objectives： This study aimed to evaluate the in vitro antioxidant capacity, to determine the anti-inflammatory effect due to lipoxygenase inhibition and to test the antimicrobial activity of ethanolic extracts from leaves of seven climbing species belonging to the Bignoniaceae family. These species are Adenocalyrnrna rnarginatum （Cham.） DC., Amphilophium vauthieri DC., Cuspidaria convoluta （VEIL） A. H. Gentry, Dolichandra dentata （K. Schum.） L. G. Lohmann, Fridericia caudigera （S. Moore） L. G. Lohmann, Fridericia chica （Bonpl.） L. G. Lohmann and Tanaecium selloi （Spreng.） L. G. Lohmann. Methods： The antioxidant activity was evaluated using three methods, 2,2＇-azino-bis（3-ethylbenzothiazo line-6-sulfonic acid）（ABTS）, 2,2-diphenyl-l-picrylhydrazyl （DPPH）, and ferric reducing antioxidant power. Lipoxygenase-inhibiting activity was assayed spectrophotometrically; the result was expressed as percent inhibition. The antimicrobial activity was assessed using the agar disk diffusion method. Minimal inhibitory concentration （MIC） and minimal bactericidal]fungicidal concentration were also determined for each extract against 12 pathogenic bacterial strains of Staphylococcus aureus and seven fungal strains of the Candida genus. The identification of the major compounds present in the most promising extract was established by high-performance liquid chromatography-tandem mass spectrometry. Results： C convoluta, F. caudigera, and F. chica exhibited the best antioxidant activity by scavenging DPPH and ABTS~ radicals and reducing Fe3＋ ion. These extracts showed a notable inhibition of lipnxygenase. F. caudigera was found to have the lower MIC value against S. aureus strains and six Candida species. The extracts of F. caudigera and C. convoluta were active even against methicillin-resistant S. aureus. C convoluta had higher total phenol content, better antioxidant activity and superior anti- inflammatory and antimicrobial activity. The main phenolic compounds found in this extract

关键词： Cuspidaria Fridericia Antioxidants Lipoxygenase Antimicrobials Herbal drugs Free radical scavengers

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

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：