检索结果-南通市图书馆

Effects of upper mantle wind on mantle plume morphology and hotspot track:Numerical modeling

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 Earth Sciences 2024年第12期67卷 3881-3899页

作者： Jie XIN Huai ZHANG Yaolin SHI felipe ORELLANA-ROVIROSA College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 100049China Department of Ocean Science and Engineering Southern University of Science and TechnologyShenzhen 518055China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Zhuhai 519080China Beijing Yanshan Earth Critical Zone National Research Station University of Chinese Academy of SciencesBeijing 101408China

A mantle thermal plume may be tilted,deflected,or even split-up by mantle lateral flows(mantle wind)during its ascent,which in turn changes the spatial distribution of various geological-magmatic responses,such as magmatic activity in the overriding plate and hotspot tracks on the surface,affecting the reliability of the constraints on absolute plate motion *** research on tilted mantle plumes has focused mainly on the lower/whole mantle *** mantle plumes formed in whole/layered mantle convection suffer lateral tilt in the upper mantle,and how this affects the magmatic activity along the surface hotspot track as well as the plume-related tectonic processes,are important scientific issues in mantle thermalplume dynamics and plate tectonics *** study introduces a thermal Stokes-fluid-dynamics numerical model(in ASPECT software)and pyrolite parameters constrained by mineral physics data,and quantitatively analyzes the tilted/deflected morphology of upper-mantle plumes and the concomitant surface-hotspot location-evolution characteristics under the combined effects of overriding-plate-motion driven flow(Couette)and upper mantle counter-flow(Poiseuille).We find that this composite upper-mantle wind can lead to(1)Plume head-and-upper-conduit horizontal motion in the opposite direction of the overriding plate motion and also with respect to the conduit roots,such that the magmatic spacing is increased;(2)Near-periodic split-up and ascent of a laterally-moving plume conduit,whose split-up/ascent period depends mainly on the thermo-chemical buoyancy of the plume itself;and(3)Under specific conditions of thermo-chemical buoyancy of a main“parent”plume interacting with upper mantle winds,two secondary“child”plumes hundreds of kilometers apart can sprout and ascend sequentially/subsimultaneously through the upper mantle in a very short period of time(2–4 Myr).The resulting oscillating/jumping behavior of hotspot locations along the overriding pl

关键词： Hotspot track Mantle plume Upper mantle wind Absolute plate motion Plume-derived magmatism Numerical modeling

Chiral Symmetry Breaking for Fermions Charged under Large Lie Groups

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2019年第4期71卷 410-416页

作者： felipe J.Llanes-Estrada Alexandre Salas-Bernardez Depto.Fisica Teorica Universidad Complutense de Madrid

We reexamine the dynamical generation of mass for fermions charged under various Lie groups with equal charge and mass at a high Grand Uni?cation scale, extending the Renormalization Group Equations in the perturbativ... 详细信息

关键词： standard model group running fermion mass grand unification scale

Compartmentalized necroptosis activation in excitotoxicityinduced axonal degeneration: a novel mechanism implicated in neurodegenerative disease pathology

在线全文

学校读者我要写书评

暂无评论

Neural Regeneration Research 2019年第8期14卷 1385-1386页

作者： Macarena S. Arrazola felipe A. Court Center for Integrative Biology Faculty of Sciences Universidad Mayor de Chile Santiago CnileFONDAP Center for Geroscience Brain Health and Metabolism Santiago Chile Buck Institute for Research on Ageing Novato San Francisco CA USA

Excitotoxicity and neuronal cell death: Glutamate is the main excitatory neurotransmitter of the central nervous system and functionally involved in most brain activities, including brain development, synaptic plasticity, learning and memory. Exc让atory synaptic transmission is primarily mediated by ligana-gated ion channels, including a-amino-3-hydroxy-5-methylisoxazoIe-4-propionic acid (AMPA), N-methyl-D-aspartate (NMDA) and kainate receptors. Activation of glutamate receptors, particularly NMDA receptors, usually leads to calcium influx, whicn can act as a second messenger for several processes to mediate synaptic activity and brain function. Nevertheless, excessive release of glutamate neurotransmitter may produce intracellular calcium overload, leading to a cascade of events mediating cytoskeleton damage accompanied w让h reactive oxygen species (ROS) generation, mitochondrial dysfunction and ultimately neuronal cell death. These toxic effects of glutamate are known as excitotoxicity. Neuronal excitotoxicity has been linked to several acute and chronic brain diseases, such as stroke/ischemia, epilepsy and a range of neurodegenerative disorders, including Alzheimer's disease (AD), Huntingtons disease, amyotrophic lateral sclerosis (ALS) and Parkinsons disease (PD), contributing to the neuronal lost in different brain regions. Unfortunately, treating nervous system disorders with general glutamate receptor blockers has been associated with undesirable side effects, becoming increasingly necessary to unravel downstream effectors in the excitotoxicity-dependent cell death pathway in order to develop novel therapeutic strategies.

关键词： Compartmentalized necroptosis activation excitotoxicityinduced axonal neurodegenerative disease

On a Class of Solutions to the Generalized Derivative Schrodinger Equations

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2019年第6期35卷 1057-1073页

作者： felipe LINARES Gustavo PONCE Gleison N.SANTOS IMPA Estrada Dona Castorina 110 Rio de Janeiro 22460-320 RJ Brazil University of California Santa Barbara CA 93106 USA Universidade Federal do Piaui-UFPI.Campus Ministro Petronio Portella Teresina 64049-550 PI Brazil

In this work we shall consider the initial value problem associated to the generalized derivative Schr?dinger(gDNLS) equations ■ and ■ Following the argument introduced by Cazenave and Naumkin we shall establish the local well-posedness for a class of small data in an appropriate weighted Sobolev space. The other main tools in the proof include the homogeneous and inhomogeneous versions of the Kato smoothing effect for the linear Schr?dinger equation established by Kenig–Ponce–Vega.

关键词： Derivative nonlinear Schrodinger local well-posedness

Factors affecting the spatial distribution and breeding habitat of an insular cliff-nesting raptor community

在线全文

学校读者我要写书评

暂无评论

Current Zoology 2018年第2期64卷 173-181页

作者： Beneharo RODRIGUEZ Airam RODRiGUEZ felipe SIVERIO Manuel SIVERIO Canary Islands' Ornithology and Natural History Group (GOHNIC) La Malecita s/n 38480 Buenavista del NorteTenerife Canary Islands Spain Department of Evolutionary Ecology Estacion Biologica de DoSana (CSIC)Avda. Americo Vespucio s/n Seville 41092 Spain

The specific spatial distribution and habitat association--strongly influenced by environmental fac- tors or competitive interactions--are major issues in ecology and conservation. We located and georeferenced nesting sites of five cliff-nesting raptors （Egyptian vulture Neophron percnopterus [a locally extinct species], common buzzard Buteo buteo, osprey Pandion haliaetus, common kes- trel Falco tinnunculus, Barbary falcon Falco peregrinus pelegrinoides）, and common raven Corvus corax on one of the most biodiverse hotspot within the Canary Islands （Teno, Tenerife）. We used generalized linear models to evaluate the factors affecting abundance, richness, and intra- and interspecific interactions. Raptor abundance increased with slope, shrub-covered area, and habitat diversity, and decreased with altitude, and forested and grassed areas. Richness increased with slope and decreased with altitude. Threatened species （osprey, Barbary falcon, and raven） occu- pied cliffs farther away from houses and roads, and more rugged areas than the non-threatened species. The models suggested that the probability of cliff occupation by buzzards, falcons, and rav- ens depended only on inter-specific interactions. Buzzard occupation increased with the distance to the nearest raven and kestrel nests, whereas falcons and ravens seek proximity to each other. Teno holds between 75% and 100% of the insular breeding populations of the most endangered species （osprey and raven）, indicating the high conservation value of this area. Our study suggests that the preservation of rugged terrains and areas of low human pressure are key factors for raptor conservation and provide basic knowledge on the community structure and habitat associations to develop appropriated management actions for these fragile island populations.

关键词： Canary Islands competitive interactions human disturbances habitat threatened species.

Synthetic Time Series Generation Model for Analysis of Power System Operation and Expansion with High Renewable Energy Penetration

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 Modern Power Systems and Clean Energy 2021年第4期9卷 849-858页

作者： Rodrigo Palma-Behnke Jorge Vega-Herrera felipe Valencia Oscar Nunez-Mata Energy Center Department of Electrical EngineeringFaculty of Mathematical and Physical SciencesUniversity of ChileSantiagoChile Department of Electrical Engineering University of AntofagastaAntofagastaChile School of Electrical Engineering University of Costa RicaSan PedroCosta Rica

The increasing integration of renewable energy sources into current power systems has posed the challenge of adequately representing the statistical properties associated with their variable power generation. In this paper, a novel procedure is proposed to select a proper synthetic time series generation model for renewable energy sources to analyze power system problems. The procedure takes advantage of the objective of the specific analysis to be performed and the statistical characteristics of the available time series. The aim is to determine the suitable model to be used for generating synthetic time series of renewable energy sources. A set of indicators is proposed to verify that the statistical properties of synthetic time series fit the statistical properties of the original data. The proposal can be integrated into systematic tools available for data analysis without compromising the representation of the statistical properties of the original time series. The procedure is tested using real data from the New Zealand power system in a mid-term analysis on integrating wind power plants into the power system. The results show that the proposed procedure reduces the error obtained in analyzing power systems compared with reference models.

关键词： Time series analysis renewable energy source solar energy stochastic process statistical analysis wind energy

Fast global kernel fuzzy c-means clustering algorithm for consonant/vowel segmentation of speech signal

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science C(Computers and Electronics) 2014年第7期15卷 551-563页

作者： Xian ZANG felipe P. VISTA IV Kil To CHONG Department of Electronic Engineering Jeonbuk National University Advanced Electronics and Information Research Center Jeonbuk National University

We propose a novel clustering algorithm using fast global kernel fuzzy c-means-F(FGKFCM-F), where F refers to kernelized feature space. This algorithm proceeds in an incremental way to derive the near-optimal solution by solving all intermediate problems using kernel-based fuzzy c-means-F(KFCM-F) as a local search procedure. Due to the incremental nature and the nonlinear properties inherited from KFCM-F, this algorithm overcomes the two shortcomings of fuzzy c-means(FCM): sen- sitivity to initialization and inability to use nonlinear separable data. An accelerating scheme is developed to reduce the compu-tational complexity without significantly affecting the solution quality. Experiments are carried out to test the proposed algorithm on a nonlinear artificial dataset and a real-world dataset of speech signals for consonant/vowel segmentation. Simulation results demonstrate the effectiveness of the proposed algorithm in improving clustering performance on both types of datasets.

关键词： Fuzzy c-means clustering Kernel method Global optimization Consonant/vowel segmentation

A prototype for on-site generation of chlorinated disinfectant for use in rural aqueducts

在线全文

学校读者我要写书评

暂无评论

Water Science and Engineering 2024年第1期17卷 33-40页

作者： Diana Marcela Cuesta Parra felipe Correa Mahecha Andrés felipe Rubio Pinzon Davidcamilo Ramirez Bustos Leonel Alveyro Teran Llorente Miguel Fernando Jimenez Jimenez Chemical and Environmental Engineering Department Fundacion Universidad de AmericaBogota 117111Colombia Chemical Engineering Department Fundacion Universidad de AmericaBogota 117111Colombia Mecanical Engineering Department Fundacion Universidad de AmericaBogota 117111Colombia

Sodium hypochlorite has significant potential as a sanitation solution in hard-to-reach *** studies have investigated the optimal electrolysis parameters for its production with volumes greater than 1o *** study evaluated sodium hypochlorite production through electrolysis in a 22-L prototype and identified the optimal operating *** were performed using graphite electrodes with areas of 68.4 cm^(2) at the laboratory scale and 1865.0 cm^(2) at the prototype scale.A design for experiments with different operating times,chloride concentrations,and electric current intensities was *** optimal operating time,sodium chloride concentration,and current intensity at the laboratory scale were 120 min,150 g of chloride per liter,and 3 A,respectively,leading to the production of 5.02 g/L of the disinfectant with an energy efficiency of 12.21 mg of Cl_(2) per *** the prototype scale,the maximum sodium hypochlorite concentration of 3.99 g of chloride per liter was achieved with an operating time of 120 min,a sodium chloride concentration of 100 g of chloride per liter,and a current intensity of 70 A,reaching an energy efficiency of 42.56 mg of Cl_(2) per *** addition,this study evaluated the influences of the chloride concentration,current intensity,and operating time on the production of sodium hypochlorite at the two scales,and formulated the equations showing the trends of sodium hypochlorite production and energy efficiency in the electrochemical *** 22-L prototype model for production of this oxidizing substance is promising for disinfection of large volumes of water in areas that are difficult to access.

关键词： Disinfection Electrolysis Energy efficiency Optimization Sodium hypochlorite

Prey and predators perceive orb-web spider conspicuousness differently: evaluating alternative hypotheses for color polymorphism evolution

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Current Zoology 2019年第5期65卷 559-570页

作者： Nathalia G.XIMENES felipe M.GAWRYSZEWSKI Animal Colouration and Evolution Lab Departamento de ZoologiaInstituto de Ciencias BiologicasUniversidade de BrasiliaBrasiliaDF70910-900Brazil Pos-Graduaqao em Ecologia e Evoluqao Universidade Federal de GoiasCampus SamambaiaGoianiaGO74690-900Brazil

Color polymorphisms have been traditionally attributed to apostatic *** perception of color depends on the visual system of the *** models predict that differently perceived degrees of conspicuousness by two predator and prey species may cause the evolution of polymorphisms in the presence of anti-apostatic and apostatic *** spider Gasteracantha cancriformis(Araneidae)possesses several conspicuous color *** orb-web spiders,the prey attraction hypothesis states that conspicuous colors are prey lures that increase spider foraging success via flower ***,polymorphism could be maintained if each morph attracted a different prey species(multiple prey hypothesis)and each spider mimicked a different flower color(flower mimicry hypothesis).Conspicuous colors could be a warning signal to predators because of the spider's hard abdomen and *** predators could perceive morphs differently and exert different degrees of selective pressures(multiple predator hypothesis).We explored these 3 hypotheses using reflectance data and color vision modeling to estimate the chromatic and achromatic contrast of *** morphs as perceived by several potential prey and predator *** results revealed that individual taxa perceive the conspicuousness of morphs ***,the multiple prey hypothesis and,in part,the multiple predator hypothesis may explain the evolution of color polymorphism in ***,even in the presence of anti-apostatic *** flower mimicry hypothesis received support by color metrics,but not by color vision *** parameters not evaluated by color vision models could also affect the perception of morphs and influence morph survival and polymorphism stability.

关键词： aposematism Araneidae Gasteracantha cancriformis luring prey attraction visual communication