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public and private Investment in the port Sector in mexico, 2000-2010： A Study Through Data Envelopment Analysis

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chinese Business Review 2014年第1期13卷 34-41页

作者： Odette V. Delfin-Ortega César l. Navarro-chàvez Universidad michoacana de San Nicolfis de Hidalgo Morelia Michoacb.n M6xico

Knowing the level of efficiency of investment applied in ports of mexico is relevant information for the design of port policies that contribute to its development and thus to greater freight movement. The objective of this paper is to analyze the technical efficiency obtained from International mexican ports, through the use of the technique of Data Envelopment Analysis （DEA）. It uses data regarding public and private investment in ports applied during the period 2000-2010 and its influence on the number of Twenty-foot Equivalent Unit （TEU）. Because it has been applied the DEA-CCR （the linear programming model） model input oriented, thus not only the efficiency is calculated in ports, but benchmarking is also obtained to determine the efficient ports that serve as reference to those who were found to be inefficient. The results obtained showed that manzanillo and progreso were the most efficient ports. On the other hand, the ports that were not efficient for any of the years reviewed were mazatlan and lazaro cardenas. Generally, public investment has been increasing over the period, and public policies are not designed to allow the ports to have an international projection.

关键词： ports investment Data Envelopment Analysis (DEA) technical efficiency

predicting Ecosystem Response to perturbation from Thermodynamic Criteria

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Journal of modern physics 2011年第6期2卷 627-635页

作者： V. Alonso chávez K michaelian 不详

The response of ecosystems to perturbations is considered from a thermodynamic perspective by acknowl-edging that, as for all macroscopic systems and processes, the dynamics and stability of ecosystems is sub-ject to definite thermodynamic law. For open ecosystems, exchanging energy, work, and mass with the en-vironment, the thermodynamic criteria come from non-equilibrium or irreversible thermodynamics. For ecosystems during periods in which the boundary conditions may be considered as being constant, it is shown that criteria from irreversible thermodynamic theory are sufficient to permit a quantitative prediction of ecosystem response to perturbation. This framework is shown to provide a new perspective on the popula-tion dynamics of real ecosystems.

关键词： population Dynamics Ecosystem perturbation Non-Equilibrium Thermodynamics Enrichment paradox

The differential genetic signatures related to climatic landscapes for jaguars and pumas on a continental scale

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Integrative Zoology 2021年第1期16卷 2-18页

作者： marina ZANIN Noa GONZAlEZ-BORRAJO Cuauhtémoc chÁvez Yamel RUBIO Bart HARmSEN Claudia KEllER pablo VIllAlVA Ana carolina SRBEK-ARAUJO leonora pires COSTA Francisco pAlOmARES Biology Department Federal University of MaranhãoSão LuísBrazil Departamento de Biologia de la Conservación Estación Biológica de DoñanaSevillaSpain Departamento de Ciencias Ambientales Universidad Autónoma MetropolitanaMexico CityMexico Escuela de Biologia Universidad Autónoma de SinaloaCuliacánMexico panthera New YorkUSA Biodiversity Coordination Amazon Research InstituteManausBrazil Biology Department Vila Velha UniversityVila VelhaBrazil Biological Sciences Department Federal University of Espírito SantoVitóriaBrazil

modern and paleoclimate changes may have altered species dynamics by shifting species’niche suitability over space and *** analyze whether the current genetic structure and isolation of the two large American felids,jaguar(panthera onca)and puma(puma concolor),are mediated by changes in climatic suitability and connection routes over modern and paleoclimatic *** estimate species distribution under 5 climatic landscapes(modern,Holocene,last maximum glaciations[lmG],average suitability,and climatic instability)and correlate them with individuals’genetic isolation through causal modeling on a resemblance *** species exhibit genetic isolation patterns correlated with lmG climatic suitability,suggesting that these areas may have worked as“allele refuges.”However,the jaguar showed higher vulnerability to climate changes,responding to modern climatic suitability and connection routes,whereas the puma showed a continuous and gradual transition of genetic *** differential responsiveness to climate change,both species are subjected to the climatic effects on genetic configuration,which may make them susceptible to future climatic changes,since these are progressing faster and with higher intensity than changes in the ***,the effects of climatic changes should be considered in the design of conservation strategies to ensure evolutionary and demographic processes mediated by gene flow for both species.

关键词： causal modeling climatic landscape ecological niche modeling gene flow linear mixed model

Slope Instability on pyroclastic Deposits: landslide Distribution and Risk mapping in Zacapoaxtla, Sierra Norte De puebla, mexico

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Journal of mountain Science 2006年第1期3卷 1-19页

作者： Borja-Baeza R.C. Esteban-chávez O marcos-lópez J. pea-garnica R.J. Alcántara-Ayala I. Institute of Geography UNAm Circuito Exterior C.U. Coyoacan 04510 mexico D.F. Institute of Geography UNAM Circuito Exterior C.U. Coyoacan 04510 Mexico D.F.Institute of Geography UNAM Circuito Exterior C.U. Coyoacan 04510 Mexico D.F.Institute of Geography UNAM Circuito Exterior C.U. Coyoacan 04510 Mexico D.F.Institute of Geography UNAM Circuito Exterior C.U. Coyoacan 04510 Mexico D.F.

In October 1999, rainfall induced landslides devastated different communities of the Sierra Norte, puebla, causing more than 250 victims and economic losses greater than $ 450 million. The town of Zacapoaxtla was one of the sectors most affected by slope instability due to the existing geological features and geomorphic characters determined by material properties, landforms and processes. Extensive areas formed by pyroclastic piedmonts developed on the Quaternary volcanic ignimbrite deposits highly dissected by marginal gully erosion combined with an extreme rainfall event played a significant role as an ideal scenario for the occurrence of landsliding. Distribution of landslides triggered by rainfall within the main sector of the Zacapoaxtla municipality was analyzed by using IKONOS images in terms of exploring the likely relationship between mass movement incidence and levels of vegetation density. The later was undertaken by means of producing an NDVI and applying a fragmentation algorithm. Finally, a map of potential areas of mass movements risk was produced based on the combination of a socio-economic vulnerability index, geologic and geomorphological maps and the spatial landslide distribution.

关键词： Rainfall landslides IKONOS vegetation density risk mexico

Design and characterization of Ti6Al4V/20CoCrmo−highly porous Ti6Al4V biomedical bilayer processed by powder metallurgy

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Transactions of Nonferrous metals Society of china 2021年第1期31卷 178-192页

作者： E.mIHAlCEA H.J.VERgaRA-HERNÁNDEZ O.JImENEZ l.OlmOS J.chÁvez D.ARTEAga División de Estudios de posgrado e Investigación Tecnológico Nacional de México/ITMoreliaAv.Tecnológico#1500Colonia Lomas de SantiaguitoMoreliaC.P.58120México Universidad de Guadalajara DIPJoséGuadalupe Zuno#48Los BelenesZapopanC.P.45100México INICIT Universidad Michoacana de San Nicolás de HidalgoFco.J.Mujica S/NMoreliaC.P.58060México Departamento de Ingeniería mecánica Eléctrica CUCEIUniversidad de GuadalajaraBlvd.Marcelino García Barragán 1421OlímpicaC.P.44430 GuadalajaraJaliscoMéxico Centro de Geociencias Universidad Nacional Autónoma de MéxicoBlvd.Juriquilla No.3001Querétaro 76230México

The aim of this work was to develop a Ti6Al4V/20CoCrmo−highly porous Ti6Al4V bilayer for biomedical *** powder metallurgy technique,with semi-solid state sintering as consolidation step,was employed to fabricate samples with a compact top layer and a porous bottom layer to better mimic natural *** densification behavior of the bilayer specimen was studied by dilatometry and the resulting microstructure was observed by scan electron microscopy(SEm)and computed microtomography(CmT),while the mechanical properties and corrosion resistance were evaluated by compression and potentiodynamic tests,*** results indicate that bilayer samples without cracks were obtained at the interface which has no negative impact on the *** values of the highly porous layer were in the lower range of those of human *** compression behavior is dictated by the highly porous Ti6Al4V ***,the corrosion resistance of Ti6Al4V/20CoCrmo is better than that of Ti6Al4V,which improves the performance of the bilayer *** work provides an insight into the important aspects of a bilayer fabrication by powder metallurgy and properties of Ti6Al4V/20CoCrmo−highly porous Ti6Al4V structure,which can potentially benefit the production of customized implants with improved wear performance and increased in vivo lifetime.

关键词： bilayer structure composites porosity sintering permeability compression behavior corrosion

NASA’s pioneer Spacecraft Anomaly, Heat, Dark matter and a probable persuasive Genesis

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Journal of High Energy physics, Gravitation and Cosmology 2023年第4期9卷 1356-1373页

作者： leandro meléndez lugo Esteban chávez Alarcón Instituto Nacional de Investigaciones Nucleares Centro Nuclear de M&eacutexico Ciudad de M&eacutexico M&eacutexico Departamento de Fí sica La Marquesa Ocoyoacac Ciudad de M&eacutexico M&eacutexico

An analysis is performed on what is known as the anomaly of NASA’s probe spacecraft. It explains why this additional acceleration can hardly be caused by the heat emitted by the electronic equipment of the spacecraft or by the dark matter that the Solar System could contain. Additionally, the correct stellar dynamics are mathematically demonstrated to explain the high speed of stellar rotation directly in galaxies and to show that this dynamics governing galaxies is very different from the dynamics of the Solar System. This also demonstrates the superfluity of postulating the existence of Dark matter at the galactic level. It is concluded that the anomaly of the pioneer spacecraft is relatively feasible as a product of an explainable difference between the modeling of the 70s and the real sources of the gravitational field of the Solar System. Therefore, it is claimed that there were sources of gravitational field that were not included in the original modeling because they were unknown at the time. Finally, a particular distribution of the disperse Solar System mass is proposed that could represent the sources of the field that give a plausible explanation for the NASA spacecraft anomaly.

关键词： Dark matter pioneers 10 and 11 galactic Radial Velocity Gravitation Radiation pressure

The Neutron and Dark matter in the Standard model of particle physics

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Journal of High Energy physics, Gravitation and Cosmology 2022年第2期8卷 402-416页

作者： leandro meléndez lugo Esteban chávez Alarcón Instituto Nacional de Investigaciones Nucleares Centro Nuclear de México Departamento de Física La Marquesa Ocoyoacac Estado de México México

The existence of the neutron, originally postulated to justify the stability of the nucleus, is very similar to the postulation of Dark matter to give stability to galaxies and galaxy clusters. However, the existence of the neutron has been proven as an important part of the nucleus that is linked within its integral structure in the Standard model of particle physics. The Standard model that began with the electron and the proton, currently, with more than one hundred particles, shows in some parts, cracks that induce to reconsider the veracity of the theories and models. Here it is established that all theories are to some extent false and therefore, so will any model, which is always a specific part of the theory. Also, like several other things, by means of a mathematical calculation, it is clarified why, it has not been possible to incorporate the Dark matter within the Standard model. Furthermore, it is reliably demonstrated that the introduction of the Dark matter postulate is superfluous and that the high speeds of stellar rotation determined experimentally are analytically explained with the stellar dynamics described here.

关键词： Neutron Standard model Dark matter Rotational Speed Stellar Dynamics

Corrosion and tribocorrosion behavior of Ti6Al4V/xTiN composites for biomedical applications

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Transactions of Nonferrous metals Society of china 2022年第2期32卷 540-558页

作者： J.chÁvez O.JImÉNEZ D.BRAVO-BARCENAS l.OlmOS F.AlVARADO-HERNÁNDEZ m.A.GONZÁlEZ A.BEDOllA-JACUINDE m.FlORES Departamento de Ingeniería mecánica Eléctrica CUCEIUniversidad de GuadalajaraBlvd.Marcelino García Barragán#1421GuadalajaraC.P.44430México Departamento de Ingeniería de proyectos CUCEIUniversidad de GuadalajaraJoséGuadalupe Zuno#48Los BelenesZapopanC.P.45150México Departamento de Ingeniería de proyectos CUCEIUniversidad de Guadalajara-CONACyTBlvd.Marcelino García Barragán#1421GuadalajaraC.P.44430México Instituto de Investigaciones en Ciencias de la Tierra INICITUniversidad Michoacana de San Nicolás de HidalgoAv.Francisco J.Mujica S/NCiudad UniversitariaMoreliaMichoacánC.P.58030México Unidad Académica de Ingeniería I Universidad Autónoma de ZacatecasAv.López Valverde 801ZacatecasZacatecasC.P.98060México Instituto de Investigaciones metalúrgicas IIMMUniversidad Michoacana de San Nicolás de HidalgoEdificio‘‘U-5’’Ciudad UniversitariaMoreliaMichoacánC.P.58030México

The corrosion and tribocorrosion behavior of Ti6Al4V/xTiN(x=0,5,10 and 15,vol.%)composites fabricated by solid-state sintering and their relationship with the microstructure and microhardness were *** body conditions such as a temperature of 37℃ and a simulated body fluid were *** main results demonstrated a microstructural change caused by theα-Ti stabilization due to solid-solution of nitrogen(N)into the titanium(Ti)lattice,producing a maximum hardening effect up to 109%for the Ti64 matrix by using 15 vol.%*** potentials of composites changed to more noble values with the TiN particle addition,while corrosion current density of samples increased as an effect of the remaining porosity,decreasing the corrosion resistance of ***,changes to a less passive behavior were observed for samples with 15 vol.%*** non-passive behavior of composites resulted in the reduction of the potential drops during rubbing in tribocorrosion ***,an improvement of up to 88%of the wear rate of composites was seen from the solid-solution *** results allowed to understand the relationship between composition and sintering parameters with the improved tribocorrosion performance of materials.

关键词： Ti64 alloy composites powder metallurgy microstructure corrosion tribocorrosion

physico-chemical and microbiological Analysis of Water of the “presa De los patos” in the Desierto De los leones National park, mexico

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Advances in Biological chemistry 2017年第2期7卷 122-138页

作者： luis Raúl Gutiérrez-lucas luz maría chávez-Ramírez leticia Arregui Departamento de Ciencias Naturales DCNI Universidad Aut&oacute noma metropolitana Unidad Cuajimalpa M&eacute xico City M&eacute xico Secretarí a de Salud Centro de Salud TI Memetla M&eacute xico City M&eacute xico

The Desierto de los leones National park is a place that features recreational activities for residents and visitors to mexico City. The presa de los patos (Ducks Dam) is one of the many bodies of water that are present in the park. By means of physico-chemical and microbiological analysis, it was determined that the water of the presa de los patos cannot be considered potable. The pH range was between 5.5 - 5.9. The turbidity exceeded the values established in the standards (10.7 - 32.3 Nephelometric Turbidity Units (NTU’s)). chemical Oxygen Demand (COD) showed that large amounts of oxygen are needed to oxidize organic matter (106 - 450 mg/l). The amount of coliforms and fecal coliforms exceeds the values established by the standards used (total coliforms 98 - 956 Colony Forming Units (CFU’s), fecal coliforms 78 - 807 CFU’s). Five bacterial genera (Escherichia coli, pseudomona, Klebsiella, Shigella and Salmonella) were isolated and identified. most of the bacteria isolated were resistant to ampicillin (90%), while 25% were resistant to ciprofloxacin. The water consumption of the presa de los patos is a great risk for the habitants and visitors of the park.

关键词： Water physico-chemical microbiological Antimicrobial Resistance Antibiotics