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Pseudostress-BasedMixed Finite Element Methods for the Stokes Problem in Rn with Dirichlet Boundary Conditions.I:A Priori Error Analysis

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Communications in Computational Physics 2012年第6期12卷 109-134页

作者： Gabriel n.Gatica Antonio Marquez Manuel A.sanchez CI2MA and Departamento de Ingenier´ıa Matem´atica Universidad de Concepci´onCasilla 160-CConcepcionChile Departamento de Construcci´on e Ingenier´ıa de Fabricacion Universidad de OviedoOviedoEspa-na.

We consider a non-standard mixed method for the Stokes problem in Rn,n∈{2,3},with Dirichlet boundary conditions,in which,after using the incompressibility condition to eliminate the pressure,the pseudostress tensor s and the velocity vector u become the only ***,we apply the Babuˇska-Brezzi theory to prove the well-posedness of the corresponding continuous and discrete *** particular,we show that Raviart-Thomas elements of order k≥0 for s and piecewise polynomials of degree k for u ensure unique solvability and stability of the associated Galerkin *** addition,we introduce and analyze an augmented approach for our pseudostress-velocity *** methodology employed is based on the introduction of the Galerkin least-squares type terms arising from the constitutive and equilibrium equations,and the Dirichlet boundary condition for the velocity,all of them multiplied by suitable stabilization *** show that these parameters can be chosen so that the resulting augmented variational formulation is defined by a strongly coercive bilinear form,whence the associated Galerkin scheme becomes well posed for any choice of finite element *** instance,Raviart-Thomas elements of order k≥0 for s and continuous piecewise polynomials of degree k+1 for u become a feasible choice in this ***,extensive numerical experiments illustrating the good performance of the methods and comparing them with other procedures available in the literature,are provided.

关键词： Mixed finite element pseudostress incompressible flow

Contact problem for regular hexagon weakened with full-strength hole

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Applied Mathematics and Mechanics(English Edition) 2013年第2期34卷 239-248页

作者： n.ODISHELIDZE F.CRIADO-ALDEAnUEVA J.M.sanchez Department of Computer Sciences Tbilisi State University Department of Applied Physics Ⅱ Polytechnic School Malaga University Department of Statistics and Operative Research Malaga University

A problem of the plane elasticity theory is addressed for a doubly connected body with an external boundary of the regular hexagon shape and with a 6-fold symmetric hole at the center. It is assumed that all the six sides of the hexagon are subjected to uniform normal displacements via smooth rigid stamps, while the uniformly distributed normal stress is applied to the internal hole boundary. Using the methods of complex analysis, the analytical image of Kolosov-Muskhelishvili＇s complex potentials and the shape of the hole contour are determined from the condition that the circumferential normal stress is constant along the hole contour. numerical results are given and shown in relevant graphs.

关键词： plate elasticity theory complex variable theory stress state regular polygon

MEC-based architecture for interoperable and trustworthy internet of moving things

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Digital Communications and networks 2023年第1期9卷 270-279页

作者： Jesus sanchez-Gomez Rafael Marin-Perez Ramon sanchez-Iborra Miguel Angel Zamora Department of Information and Communications Engineering University of MurciaMurciaSpain Odin Solutions S.L. MurciaSpain University Center of Defense San Javier Air Force BaseMurciaSpain

The expansion of the Internet of Moving Things(IoMT)leads to limitless and continuous working playgrounds exploited by highly dynamic end *** requires the adoption of multi-Radio Access Technologies(RATs)-based strategies to provide IoMT units with ubiquitous *** this end,the development of secure bootstrapping and authentication mechanisms is necessary to permit the secure operation of end *** the transmission and power limitations of these elements,current cryptographic solutions do not address these stringent *** that reason,in the study we present a Multi-Access Edge Computing(MEC)-based endto-end architecture that enables an efficient and secure authentication and key agreement between end devices and network servers over heterogeneous resource-limited networks such as the Low Power Wide Area networks(LPWAns).Our proposal is based on the Authentication,Authorization,and Accounting(AAA)architecture and the recent Internet Engineering Task Force initiatives Static Context Header Compression and Low-Overhead *** results obtained from experimental tests reveal the validity of the proposal as it enables constrained IoMT devices to gain IPv6 connectivity as well as performs end-to-end secure authentication with notable reliability and controlled latency.

关键词： Internet of moving things LPWAn Authentication LO-CoAP-EAP SCHC

Black holes in asymptotic safety with higher derivatives:accretion and stability analysis

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Chinese Physics C 2021年第7期45卷 293-304页

作者： Fabian H.Zuluaga Luis A.sanchez Escuela de Fisica Universidad Nacional de ColombiaA.A.3840MedellinColombia

We review steady spherically symmetric accretion onto a renormalization group improved Schwarzschild space-time,which is a solution to an asymptotically safe theory(AS)containing high-derivative *** use a Hamiltonian dynamical system approach for the analysis of the accretion of four types of isothermal test fluids:ultra-stiff fluid,ultra-relativistic fluid,radiation fluid,and sub-relativistic *** important outcome of our study is that,contrary to the claim in a recent work,there are physical solutions for the accretion of an ultra-relativistic fluid in AS,which include subsonic,supersonic,and transonic ***,we study quantum corrections to the known stability of the accretion in general relativity(GR).To this end,we use a perturbative procedure based on the continuity equation with the mass accretion rate being the perturbed *** classes of perturbations are studied:standing and traveling *** find that quantum gravity effects either enhance or diminish the stability of the accretion depending on the type of test fluid and the radial distance to the central object.

关键词： asymptotic safety black holes accretion stability

P-functionalized carbon nanotubes promote highly stable electrocatalysts based on Fe-phthalocyanines for oxygen reduction: Experimental and computational studies

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Journal of Energy Chemistry 2022年第9期31卷 276-290,I0008页

作者： Beatriz Martinez-sanchez Diego Cazorla-Amors Emilia Morallon Departamento de Quimica Fisica and Instituto Universitario de Materiales de Alicante(IUMA)University of Alicante Ap.99.03080 AlicanteSpain Departamento de Quimica Inorganica and Instituto Universitario de Materiales de Alicante(IUMA) University of AlicanteAp.9903080 AlicanteSpain

Iron(Ⅱ) phthalocyanines(FePc) supported on functionalized nanostructured carbon materials have been studied as electrocatalysts for the oxygen reduction reaction(ORR) in an alkaline medium. Herein, two types of carbon nanotubes(CnTs) have been explored as support, Single-Walled Carbon nanotubes and Herringbone Carbon nanotubes(SWCnTs and h CnTs, respectively), both electrochemically modified with ortho-aminophenylphosphonic acid(2APPA), which provides phosphate axial coordinating ligands for the immobilization of FePc molecules. All the catalysts were prepared via a facile incipient wetness impregnation method. Comprehensive experimental analysis together with density functional theory(DFT) calculations has demonstrated both the importance of the five-coordinated Fe macrocycles that favor the interaction between the FePc and the carbon support, as well as the effect of the CnT structure in the ORR. FePc axial coordination provides a better dispersion, leading to higher stability and a favorable electron redistribution that also tunes the ORR performance by lowering the stability of the reaction intermediates. Interestingly, such improvement occurs with a very low content of metal(~1 wt% Fe),which is especially remarkable when h CnT support is employed. This work provides a novel strategy for the development of Fe-containing complexes as precious metal-free catalysts towards the ORR.

关键词： Carbon nanotubes Iron phthalocyanine Oxygen reduction Electrocatalysis Axial ligand

Improving automatic climate control with decision support techniques to minimize disease effects in greenhouse tomatoes

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Information Processing in Agriculture 2017年第1期4卷 50-63页

作者： Joaquın Canadas Jorge Antonio sanchez-Molina Francisco Rodrıguez Isabel Marıa del Aguila Department of Informatics University of Almerı´a04120 Almerı´aSpain The Agrifood Campus of International Excellence(ceiA3)Spain

Crop growth in greenhouses is basically determined by the climate variables in the environment and by the amounts of water and fertilizers supplied by *** management of these factors depends on the expertise of agricultural technicians and farmers,usually assisted by control systems installed within the *** this context,decision support features enable us to incorporate invaluable human experience so thatwe can take quick and effective decisions to ensure efficient crop *** work describes a real-time decision support system for greenhouse tomatoes that supports decisions at three stages–the supervision stage identifies climate sensor faults,the control stage maintains climate variables at setpoints,and the strategic stage identifies diseases affecting the crop and changes climate variables accordingly to minimize *** DSS was implemented by integrating a real-time rule-based tool into the control *** results show that the system increases climate control effectiveness,while providing support in preventing diseaseswhich are difficult to *** system was tested by simulating the appearance of the disease and observing the real *** main contribution has been to demonstrate that production rules,which aremature and well-known in the artificial intelligence domain,can act as a shared technology for the whole *** means that fault detection,temperature control and disease monitoring features are not dealt with in isolation.

关键词： Greenhouse crop growth Decision support systems Climate control Disease management

Human immunodeficiency virus type-1 induces a regulatory B cell-like phenotype in vitro

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Cellular & Molecular Immunology 2018年第10期15卷 917-933页

作者： Jacobo Lopez-Abente Adrián Prieto-sanchez Maria-Ángeles Muñoz-Fernandez Rafael Correa-Rocha Marjorie Pion Laboratorio de Inmuno-Regulación Immunology DepartmentPabellón de Medicina y Cirugía ExperimentalHospital General Universitario Gregorio MarañónInstituto de Investigación Sanitaria Gregorio Marañón(IiSGM)Calle Máiquez9Madrid 28009Spain Laboratorio de Inmuno-Biología Molecular Immunology DepartmentHospital General Universitario Gregorio MarañónInstituto de Investigación Sanitaria Gregorio Marañón(IiSGM)C/Dr.Esquerdo 46Madrid 28007Spain networking Research Center on Bioengineering Biomaterials and Nanomedicine(CIBER-BBN)C/Monforte de Lemos 3-5Pabellón 11Madrid 28029Spain

Individuals infected with human immunodeficiency virus type-1(HIV-1)usually show a general dysregulation and hyper-activation of the immune system.A direct influence of HIV-1 particles on B-cell phenotypes and functions has been previously ***,the consequences of B-cell dysregulation are still poorly *** evaluated the phenotypic changes in primary B cells after direct contact with HIV-1 particles in comparison with different types of *** functionality of treated B cells was challenged in co-culture experiments with autologous CD4+and CD8+T *** demonstrated that HIV-1 induces a phenotypic change in B cells towards a regulatory B-cell phenotype,showing a higher level of IL-10,TGF-β1,EBI3 or IL-12(p35)mRnA expression and acquiring an immunosuppressive *** acquisition of a Breg phenotype was confirmed by co-culture experiments where HIVtreated B cells reduced the proliferation and the TnFαproduction of CD4+or CD8+T *** suppressive ability of HIV-treated B cells was dependent on cell-to-cell contact between these B cells and effector *** our knowledge,these data provide the first evidence that HIV-1 can directly induce a regulatory B cell-like immunosuppressive phenotype,which could have the ability to impair specific immune *** dysregulation could constitute one of the mechanisms underlying unsuccessful efforts to develop an efficient vaccine against HIV-1.

关键词： HIV-1 immune hyper-activation regulatory B cells

Taxonomy-based differences in feeding guilds of fish

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Current Zoology 2020年第1期66卷 51-56页

作者： Javier sanchez-HERnAnDEZ Departamento de Zooloxla Xenetica e Antropoloxfa FlsicaFacultade de BioloxfaUniversidade de Santiago de CompostelaCampus Vida s/nSantiago de CompostelaEspana

It has been taken for granted that feeding guilds and behavior in animals are linked to the taxonomic relatedness of species,but empirical evidence supporting such relationship is virtually *** examine the importance of taxonomy on trophic ecology,I here present the first well-resolved dietary taxonomy analysis based on feeding guilds(predation,herbivory,and filtering)among families and genera within the fish order *** relatedness in feeding did not vary with ecosystem dimension(marine ***).Although predation dominates among Perciformes fishes,this study shows that in most cases taxonomic units(family or genus)are composed by species with several feeding *** species are more similar in feeding compared with species that are taxonomically more distant demonstrating that there is a greater variation of feeding guilds within families than ***,there is no consistency in feeding guilds between family-and genus-level *** study provides empirical support for the notion that genera are more informative than families,underlining that family-level taxonomy should be avoided to infer feeding habits of fish species at finer taxonomic ***,the choice of taxonomic resolution(family or genus level)in ecological studies is key to avoid information loss and misleading results.I conclude that high-rank taxonomic units(i.e.,above the generic level)are not appropriate to test research hypotheses about the feeding of fish.

关键词： aquatic systems clades FishBase global datasets taxonomic sufficiency trophic ecology

neurotoxicity of the pesticide rotenone on neuronal polarization: a mechanistic approach

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neural Regeneration Research 2019年第5期14卷 762-766页

作者： Mariano Bisbal Mónica sanchez Laboratory of neurobiology Instituto Mercedes y Martín Ferreyra (INIMEC-CONICET) Universidad nacional de Córdoba Instituto Universitario Ciencias Biomédicas Córdoba

neurons are the most extensive and polarized cells that display a unique single long axon and multiple dendrites, which are compartments exhibiting structural and functional differences. Polarity occurs early in neuronal development and it is maintained by complex subcellular mechanisms throughout cell life. A well-defined and controlled spatio-temporal program of cellular and molecular events strictly regulates the formation of the axon and dendrites from a non-polarized cell. This event is critical for an adequate neuronal wiring and therefore for the normal functioning of the nervous system. neuronal polarity is very sensitive to the harmful effects of different factors present in the environment. In this regard, rotenone is a crystalline, colorless and odorless isoflavone used as insecticide, piscicide and broad spectrum pesticide commonly used earlier in agriculture. In the present review we will summarize the toxicity mechanism caused by this pesticide in different neuronal cell types, focusing on a particular biological mechanism whereby rotenone could impair neuronal polarization in cultured hippocampal neurons. Recent advances suggest that the inhibition of axonogenesis produced by rotenone could be related with its effect on microtubule dynamics, the actin cytoskeleton and their regulatory pathways, particularly affecting the small RhoGTPase RhoA. Unveiling the mechanism by which rotenone produces neurotoxicity will be instrumental to understand the cellular mechanisms involved in neurodegenerative diseases influenced by this environmental pollutant, which may lead to research focused on the design of new therapeutic strategies.

关键词： rotenone environmental pollutants toxicity neuronal polarity RhoGTPase RhoA Lfc Arhgef1