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Plumbing System of Hunga Tonga Hunga Ha'apai Volcano

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Journal of Earth Science 2023年第3期34卷 706-716页

作者： Román Alvarez Miguel Camacho instituto de investigaciones en matemáticas aplicadas y en sistemas(IIMAS) Universidad Nacional Autónoma de MéxicoCoyoacán CDMX 04510Mexico Posgrado en Ciencias de la Tierra Universidad Nacional Autónoma de MéxicoCoyoacán CDMX 04510Mexico

The Hunga Tonga Hunga Ha’apai submarine volcano has experienced repeated eruptions in the latest decades.The recent one,in January 2022,released an enormous amount of energy inducing global perturbations,as tsunamis and atmospheric waves.The structure of the volcano is poorly understood,especially its internal structure.deep-seated magmatic connections are difficult to define or visualize.We use a high-resolution gravity data set obtained via satellite to calculate the Bouguer anomaly over its structure,to perform a preliminary exploration of its interior.Executing 3D gravity inversions,we find a complex plumbing system with various exhaust trajectories and multiple surface pockets of low-density material within the volcanic edifice;some appear to be associated with ring fractures.This is in line with the report of the 2009 eruption,described as beginning from multiple vents.We found no signs of a magma chamber within 6 km depth,although several volcanic conduits are identified from such depth to the surface.density variations occur within a plumbing conduit or may vary from one conduit to another in the same volcano.These models yield quantitative estimates for areas of magma-water interaction,constituting a baseline to compare with structural changes to be induced in future eruptions.

关键词： Hunga Tonga Hunga Ha'apai satellite gravity data 3D inversions volcano Tofua Island

Distribution and Relation of Primes with Tesla Numbers 3, 6, and 9

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Journal of Applied Mathematics and Physics 2024年第4期12卷 1021-1027页

作者： Javier Mendoza-Navarrete Huetzin Perez Ismael Ojeda Victor Verdugo Gabriel Luna Sandoval Ricardo Jimenez Garcia Jaime Alvarez departametno de matemá ticas CBTis 256 DGETI Cabo San Lucas M&#233xico DCI departamento de Fisica Mé dica Universidad de Guanajuato Leon M&#233xico Divisió n de Ingenieria en Sistemas Computacionales Tecnol&#243gico Nacional de M&#233xico ITES Los Cabos Cabo San Lucas M&#233xico departamento de Ingenieria Industrial en Manufactura Universidad Estatal de Sonora Navojoa M&#233xico departamento de Elé ctrica-Electr&#243nica Tecnol&#243gico Nacional de M&#233xico Campus Mexicali Mexicali M&#233xico Guanajuato M&#233xico

This work presents a different approach to twin primes, an approach from the perspective of the Tesla numbers and gives a refresh and new observation of twin primes that could lead us to an answer to the Twin Prime Conjecture problem. We expose a peculiar relation between twin primes and the generation of prime numbers with Tesla numbers. Tesla numbers seem to be present in so many domains like time, vibration and frequency [1], and the space between twin primes is not the exception. Let us say that twin primes are more than just prime numbers plus 2 or minus 2, and Tesla numbers are more involved with twin primes than we think, and hopefully, this approach give us a better understanding of the distribution of the twin pairs.

关键词： Tesla Numbers Prime Number Twin Prime Numbers Twin Pair

Interfacial effects in electromagnetic coupling within piezoelectric phononic crystals

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Acta Mechanica Sinica 2009年第1期25卷 95-99页

作者： F. J. Sabina A.B.Movchan instituto de investigaciones en matematicas aplicadas yen sistemas Universidad Nacional Autónoma de México department of Mathematical Sciences University of Liverpool

In this paper, we discuss waves in piezoelectric periodic composite, with the emphasis on the connection between the electromechanical coupling and the effects of dispersion of Bloch-Floquet waves. A particular attention is given to structures containing interfaces between dissimilar media and localization of the electrical fields near such interfaces.

关键词： Piezoelectric periodic composites Interfaces Dispersion of Bloch-Floquet waves

Almost sure, L1-and L2-growth behavior of supercritical multi-type continuous state and continuous time branching processes with immigration

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Science China Mathematics 2020年第10期63卷 2089-2116页

作者： Mátyás Barczy Sandra Palau Gyula Pap MTA-SZTE Analysis and Stochastics Research Group Bolyai InstituteUniversity of SzegedSzeged H-6720Hungary department of Statistics and Probability Instituto de Investigaciones en Matemáticas Aplicadas y en SistemasUniversidad Nacional Autònoma de MéxicoCiudad de México 04510México Bolyai Institute University of SzegedSzeged H-6720Hungary

Under a first order moment condition on the immigration mechanism,we show that an appropriately scaled supercritical and irreducible multi-type continuous state and continuous time branching process with immigration(CBI process)converges almost surely.If an x log(x)moment condition on the branching mechanism does not hold,then the limit is zero.If this x log(x)moment condition holds,then we prove L1 convergence as well.The projection of the limit on any left non-Perron eigenvector of the branching mean matrix is vanishing.If,in addition,a suitable extra power moment condition on the branching mechanism holds,then we provide the correct scaling for the projection of a CBI process on certain left non-Perron eigenvectors of the branching mean matrix in order to have almost sure and L1 limit.Moreover,under a second order moment condition on the branching and immigration mechanisms,we prove L2 convergence of an appropriately scaled process and the above-mentioned projections as well.A representation of the limits is also provided under the same moment conditions.

关键词： multi-type continuous state and continuous time branching processes with immigration almost sure L1-and L2-growth behaviour

Bats and their vital ecosystem services:a global review

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Integrative Zoology 2022年第1期17卷 2-23页

作者： Leidy Azucena RAMÍREZ-FRÁNCEL Leidy Viviana GARCÍA-HERRERA Sergio LOSADA-PRADO Gladys REINOSO-FLÓREZ Alfonso SÁNCHEZ-HERNÁNdeZ Sergio ESTRADA-VILLEGAS Burton KLIM Giovany GUEVARA Programa de Doctorado en Ciencias Biológicas&Grupo de Investigación en Zoología(GIZ) Facultad de CienciasUniversidad del TolimaIbaguéColombia Programa para la Conservación de los Murciélagos de Colombia BogotáD.C.Colombia departamento de Biología&Grupo de Investigación en Zoología(GIZ) Facultad de CienciasUniversidad del TolimaIbaguéColombia departamento de matemáticas y Estadística Facultad de CienciasUniversidad del TolimaIbaguéColombia yale School of the environment Yale UniversityNew HavenConnecticutUSA Smithsonian Tropical Research Institute BalboaRepublic of Panama department of Natural History Royal Ontario MuseumTorontoOntarioCanada

Bats play crucial ecosystem services as seed dispersers,pollinators,controllers of insects,and nutrient recyclers.However,there has not been a thorough global review evaluating these roles in bats across all biogeographical regions of the world.We reviewed the literature published during the last two decades and identified 283 relevant studies:78 dealt with the control of potential insect pests by bats,80 related to the suppression of other arthropods,60 on the dispersal of native or endemic seeds,11 dealt with the dispersal of seeds of introduced plants,29 on the pollination of native or endemic plants,1 study on pollination of introduced plants,and 24 on the use of guano as fertilizer.Our literature search showed that queries combining the terms“seed dispersal,”“insectivorous bats,”“nectarivorous bats,”“use of guano,”and“ecosystem services”returned 577 studies,but half were experimental in nature.We found that the evaluation of ecosystem services by bats has been mostly conducted in the Neotropical and Palearctic regions.To detect differences across relevant studies,and to explain trends in the study of ecosystem services provided by bats,we performed generalized linear mixed models(GLMM)fitted with a Poisson distribution to analyze potential differences among sampling methods.We identified 409 bat species that provide ecosystem services,752 insect species consumed by bats and 549 plant species either dispersed or pollinated by bats.Our review summarizes the importance of conserving bat populations and the ecological services they provide,which is especially important during the current pandemic.

关键词： chiroptera ecosystem services frugivory,guano,insectivory nectarivory pest control pollination seed dispersal

Redefinition of the Terminus of the Middle America Trench

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International Journal of Geosciences 2013年第4期4卷 766-776页

作者： Román Alvarez instituto de investigaciones en matemáticas aplicadas y en sistemas Universidad Nacional Autónoma de México Ciudad Universitaria México DF México

The terminus of the Middle America Trench has been traditionally represented as an arc, concave towards the continent. Tres Marías Islands are located at the terminus of the Middle America Trench in western Mexico, and their location is not only intriguing but also a key to the re-construction of the position of Baja California peninsula before separation from the North America plate. Previous re-constructions suggested various places around the location of Tres Marías Islands for the position of the tip of the peninsula, and several converge to a position that invades the area occupied by the islands, offering no explanation for the overlap. Before peninsular separation from North America, the Guadalupe trench followed a smooth curve;recreating the position of this paleo-trench yields a baseline for fixing the position of the peninsula, as well as the original position of the Tres Marías Islands fragment. A new tectonic view of the structure of the Middle America Trench terminus is proposed, replacing the traditional arc representation with a series of en echelon blocks, the northernmost terminates at the Tres Marías Escarpment. The long sides of the blocks correspond to previously identified geological faults in the Bahía de Banderas region, while their offshore continuation is supported by topographic observations. As a test of this model I show the corresponding re-construction of the position of Baja California prior to separation from the North America plate and the positional evolution of the peninsula and the Tres Marías fragment from Chron 4n.2 (7.90 Ma) to Chron 3n.4 (5.12 Ma).

关键词： Middle America Trench Tres Marías Islands Guadalupe Trench MAT Terminus Banderas Fault

Mechanical response to axial strain in WS2 nanotubes

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Progress in Natural Science:Materials International 2021年第6期31卷 898-903页

作者： S.Mejía-Rosales S.A.Sandoval-Salazar A.Soria-Sánchez J.D.Vázquez-Palafox Centro de Investigación en Ciencias Físico-matemáticas (CICFIM) Facultad de Ciencias Físico-Matemáticas Universidad Autónoma de Nuevo León Facultad de Ciencias Físico-matem aticas Universidad Aut onoma de Nuevo León Facultad de Ciencias Físico-matemáticas Universidad Autónoma de Nuevo León

In order to take advantage of inorganic nanotubes for their use with pragmatic purposes, characterization of their mechanical properties becomes a relevant issue. In the present study, a series of results on the mechanical properties of WS2nanotubes of several diameters and two main lattice orientations was obtained by the implementation of molecular dynamics simulations using an interatomic potential of the Stillinger-Weber kind. A young’s modulus for nanotubes of H polytype close to 170 GPa was obtained in accordance with experimental results, and of ≈ 130 GPa for nanotubes of the T polytype, with almost no dependance on the diameter of the nanotube. The tensile strength was as large as 20 GPa(H armchair nanotubes, close to the value obtained in experiments), and the strain at the point of rupture reached values close to 0.24. The effect of several kinds of defects on the mechanical properties was investigated, and the results showed that when the defects consisted in the absence of a whole WS2unit, the tensile strength and point of rupture dropped considerably, and the fracture became more brittle than in pristine nanotubes. The dependence of the mechanical properties on temperature was also investigated.

关键词： Tungsten disulfide nanotubes young's modulus Stillinger-weber Molecular dynamics

Reiterated homogenization of a laminate with imperfect contact:gain-enhancement of effective properties

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Applied Mathematics and Mechanics(english Edition) 2018年第8期39卷 1119-1146页

作者： F.E.ALVAREZ-BORGES J.BRAVO-CASTILLERO M.E.CRUZ R.GUINOVART-DIAZ L.D.PEREZ-FERNANdeZ R.RODRIGUEZ-RAMOS F.J.SABINA Facultad de matematica y Computacion Departamento de MatematicaUniversidad de La HabanaSan Lazaro y LHabana 4La HabanaCP 10400Cuba departamento de matematicas y Mecanica Universidad Nacional Autonoma de MexicoInstituto de Investigaciones en Matematicas Aplicadas y en Sistemas01000 CDMXAP 20-126M′exico departamento de engenharia Mecanica Universidade Federal do Rio de JaneiroPolitecnica/COPPECaixa Postal 68503Rio de JaneiroRJCEP 21941-972Brasil departamento de matematica e Estatistica Universidade Federal de PelotasCaixa Postal 354PelotasRio Grande do SulCEP 96010-900Brasil

A family of one-dimensional(1D) elliptic boundary-value problems with periodic and rapidly-oscillating piecewise-smooth coefficients is considered. The coefficients depend on the local or fast variables corresponding to two different structural scales. A finite number of imperfect contact conditions are analyzed at each of the scales. The reiterated homogenization method(RHM) is used to construct a formal asymptotic solution. The homogenized problem, the local problems, and the corresponding effective coefficients are obtained. A variational formulation is derived to obtain an estimate to prove the proximity between the solutions of the original problem and the homogenized problem. Numerical computations are used to illustrate both the convergence of the solutions and the gain of the effective properties of a three-scale heterogeneous 1D laminate with respect to their two-scale counterparts. The theoretical and practical ideas exposed here could be used to mathematically model multidimensional problems involving multiscale composite materials with imperfect contact at the interfaces.

关键词： reiterated homogenization method(RHM) imperfect contact variational formulation effective coefficient gain

Southward Migration of Magmatic Activity in the Colima Volcanic Complex, Mexico: An Ongoing Process

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International Journal of Geosciences 2015年第9期6卷 1077-1099页

作者： Román Alvarez Vsevolod yutsis instituto de investigaciones en matemáticas aplicadas y en sistemas Universidad Nacional Autónoma de México Ciudad Universitaria México DF México instituto Potosino de Investigación Científica y Tecnológica San Luis Potosí México

The Colima Volcanic Complex trends in a nearly N-S direction in western Mexico, and one of its?structures, Colima volcano, is the most historically active volcano in the country. Immediately to the?N, there is another volcanic center called El Cántaro volcano, whose activity started around 1.7 Ma in its N portion and migrated to the S in various episodes. Volcanic activity migrated further south, from El Cántaro to the Colima Volcanic Complex where the southernmost manifestation, Hijos del Volcán domes, is located on the south slope of Fuego volcano. The above date appears to mark initiation of the rather continuous volcanic activity in the area. It has been noted that these volcanic manifestations lie on, or near the Rivera-Cocos inland plate boundary. Colima’s Fuego volcano is also the closest to the Middle America Trench, among the polygenetic volcanoes in Mexico. We submit that the anomalous location of volcanism in this area originates in an anomalous subduction process of the Rivera and Cocos plates and evoke a tectonic model, proposed elsewhere, to support the idea. Modeling gravimetric and aeromagnetic data we locate the magma chambers of the Fuego (active) and Nevado (extinct) volcanoes within a 65 mGals negative Bouguer anomaly elongated in a nearly N-S direction. The corresponding aeromagnetic map displays a magnetic high over the southern portion of the Fuego volcano edifice. We found two additional, associated structures whose anomalies have not been previously reported, which appear to follow the southward magmatic migration pattern. One of them is a collapse structure with a circular topographic expression, and the southernmost is a low-density intrusion ~1 km below sea level, associated with a moderate topographic bulge at the surface that we interpret as a magma body. Five lines cross the anomalies;gravimetric and magnetic fields are concurrently modeled along them to locate the magmatic bodies. In addition to the 2-D models we perform 3-D gravimetric and magnetic inversions. For each field a 3-D

关键词： Colima Volcanic Complex Magma Chambers Colima Volcanoes Gravimetric Modeling Magnetic Modeling