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Impact of productive activities and urban expansion on an ecological reserve; Cuxtal´s case in Yucatán; Mexico

RAFAEL ORTIZ Henry Emmanuel Celis Fajardo J. Gerardo García-Gil (2021)

This article analyzes the socioeconomic conditions between inhabitants of the Cuxtal Ecological Reserve (REC), which suffers the effects of urban sprawl on forest cover. It was applied randomly 400 surveys in several communities located within REC to meet socioeconomic aspects and describe some productive activities that cause damages to the reserve. The results of the study indicates that the inhabitants of the reserve have not basic knowledge of the protection area. Similarly a PROBIT model analyzes how people are motivated to perform work outside the reserve due to the low level of weekly income obtained.

Article

Artículo

Ecological reserve human affectation productive activities population labor mobility Reserva ecológica actividades productivas población movilidad laboral CIENCIAS SOCIALES CIENCIAS SOCIALES

Thermodynamic, structural and dynamic properties of ionic liquids [C4mim][CF3COO]

, [C4mim][Br]

in the condensed phase, using molecular simulations

Joel Sánchez-Badillo JORGE LOPEZ LEMUS Marco Gallo Ricardo Guirado (2019)

Articulo de investigacion

In this work a series of thermodynamic, structural, and dynamical properties for the 1-butyl-3-methylimidazolium trifluoroacetate ([C4mim][CF3COO]) and 1-butyl-3-methylimidazolium bromide, ([C4mim][Br]) ionic liquids (ILs) were calculated using Non-polarizable Force Fields (FF), parameterized using a methodology developed previously within the research group, for condensed phase applications. Properties such as the Vapor-Liquid Equilibrium (VLE) curve, critical points (ρc, Tc), Radial, Spatial and Combined Distribution Functions and self-diffusion coefficients were calculated using Equilibrium Molecular Dynamics simulations (EMD); other properties such as shear viscosities and thermal conductivities were calculated using Non-Equilibrium Molecular Dynamics simulations (NEMD). The results obtained in this work indicated that the calculated critical points are comparable with those available in the literature. The calculated structural information for these two ILs indicated that the anions interact mainly with hydrogen atoms from both the imidazolium ring and the methyl chain; the bromide anion displays twice the hydrogen coordination number than the oxygen atoms from the trifluoroacetate anion. Furthermore, Non-Covalent interactions (NCI index), determined by DFT calculations, revealed that some hydrogen bonds in the [C4mim][Br] IL displayed similar strength to those in the [C4mim][CF3COO] IL, in spite of the shorter O−–H distances found in the latter IL. The majority of the calculated transport properties presented reasonable agreement with the experimental available data. Nonetheless, the self-diffusion coefficients determined in this work are under-estimated with respect to experimental values; however, by escalating the electrostatic atomic charges for the anion and cation to ±0.8e, only for this property, a remarkable improvement was obtained. Experimental evidence was recovered for most of the calculated properties and to the best of our knowledge, some new predictions were done mainly in thermodynamic states where data are not available. To validate the FF, developed previously within the research group, dynamic properties were also evaluated for a series of ILs such as [C4mim][PF6], [C4mim][BF4], [C4mim][OMs], and [C4mim][NTf2] ILs.

Article

ionic liquid molecular dynamics force field CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA

El análisis dinámico de la pobreza en México como nueva agenda de investigación: un estado de la cuestión como base para futuras indagaciones

Poverty Dynamics in Mexico as a New Research Agenda: a Literature Review as a Departure Point for Future Inquires

KATYA RODRIGUEZ GOMEZ (2016)

El artículo tiene como objetivo hacer una revisión de literatura sobre el caso de México que permita conocer el estado de la cuestión de los estudios sobre dinámica de la pobreza y movilidad social, con vistas a formular preguntas de investigación e hipótesis de trabajo que permitan continuar con la investigación sobre el tema en el futuro. Para ello la introducción discute cuál es la importancia de abordar la pobreza desde una perspectiva dinámica para el caso de México. La segunda parte revisa los estudios sobre movilidad intergeneracional. La tercera parte revisa los estudios sobre movilidad intrageneracional y dinámica de la pobreza. La última parte concluye sobre los principales hallazgos de la revisión de la literatura y formula preguntas de investigación e hipótesis de trabajo.

The paper discusses previous research on the Mexican case regarding poverty dynamics and social mobility, in order to know the main findings of the literature. The objective is to draw up research questions and hypothesis to continue researching this theme in the future. The introduction discusses the importance of

poverty dynamics as a research perspective for Mexican case. The second part describes the main findings of the literature on intergenerational mobility. The third part describes the main findings of the literature on intra-generational mobility and poverty dynamics. The last

part discusses the evidence presented and draw up research questions and hypothesis.

Article

CIENCIAS SOCIALES Dinámica de la pobreza Movilidad social México Poverty Dynamics Social Mobility Mexico

Surface tension of O2-Ar, N2-Ar and O2-N2-Ar mixtures

Mauricio Garcia-Martinez JORGE LOPEZ LEMUS BENJAMIN IBARRA TANDI (2019)

articulo de investigacion

The surface tension of some binary and ternary mixtures was calculated by means of molecular dynamics simulations in a canonical set. The analyzed mixtures were oxygen-argon, nitrogen-argon and oxygen-nitrogenargon. The force field for argon was recalculated in order to reproduce the experimental surface tension. The corresponding force fields for O2 and N2 were taken from a previous work [Mol. Simul. 45 (2019) 958-966], where it was shown that such force fields reproduce the experimental surface tension curves, as pure fluids. The nitrogen-argon surface tension was calculated for several mole fractions of argon. The obtained curve was compared with those experimental data and a good agreement was found. The standard Lorentz-Berthelot combining rules were employed. For the oxygen-argon mixture it was necessary to modify the cross term of the combining rules in order to reproduce theoretical and experimental data. The surface tension of the ternary mixture was also estimated varying the mole fraction of argon at a certain concentration of oxygen and nitrogen, previously adjusted. Several temperatures were used in order to show a tendency mostly at relatively low temperatures. After comparing the available experimental data, which are scarce, a good agreement was observed.

Article

oxygen argon molecular dynamics nitrogen CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA

Massive Influx of Pelagic Sargassum spp. on the Coasts of the Mexican Caribbean 2014-2020: Challenges and Opportunities

Valeria Chávez ABIGAIL URIBE MARTINEZ Eduardo Cuevas ROSA ELISA RODRIGUEZ MARTINEZ BRIGITTA INE VAN TUSSENBROEK RIBBINK Vanessa Francisco MIRIAM ROCIO ESTEVEZ GONZALEZ María de Lourdes Berenice Celis García LUZ VERONICA MONROY VELAZQUEZ ROSA MARIA LEAL BAUTISTA Lorenzo Alvarez_Filip MARTA GARCIA SANCHEZ LUIS MASIA NEBOT Rodolfo Silva (2020)

Since late 2014, the Mexican Caribbean coast has periodically received massive, atypical influxes of pelagic Sargassum spp. (sargasso). Negative impacts associated with these influxes include mortality of nearshore benthic flora and fauna, beach erosion, pollution, decreasing tourism and high management costs. To understand the dynamics of the sargasso influx, we used Landsat 8 imagery (from 2016 to mid-2020) to record the coverage of sargasso in the sea off the Mexican Caribbean coastline, with a maximum reported in September 2018. Satellite image analysis also showed local differences in the quantity of beached sargasso along the coastline. Over the years, good practice for collection on the beach and for off-shore collection of sargasso have been established through trial and error, and the Mexican Government and hotel industry have spent millions of dollars on removal and off-shore detention of sargasso. Notwithstanding, sargasso also has various properties that could be harnessed in local industries. The stimulation of local industrial growth would offer alternatives to the dependence on tourism, as a circular economy, based on sargasso, is developed.

Article

SARGASSO DYNAMICS OCEAN COVERAGE BEACH CAST VOLUMEN SARGASSO USES CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA CIENCIAS DE LA TIERRA Y DEL ESPACIO OCEANOGRAFÍA BOTÁNICA MARINA BOTÁNICA MARINA

Componentes del Rendimiento en Variedades De Alfalfa (Medicago Sativa L.)

ADELAIDO RAFAEL ROJAS GARCIA NICOLAS TORRES SALADO SANTIAGO JOAQUIN CANCINO ALFONSO HERNANDEZ GARAY MARIA DE LOS ANGELES MALDONADO PERALTA PAULINO SANCHEZ SANTILLAN (2017)

Alfalfa (Medicago sativa L.) is the most important legume forage for dairy cattle feed in Mexico. The objective of this

study was to assess the productive response of five varieties of alfalfa in cutting intervals defined seasonally. Our hypothesis was that the San Miguelito variety is the most productive among the evaluated varieties. The varieties San Miguelito, Júpiter, Atlixco, Vía láctea and Cuf 101 were randomly distributed in 20 experimental plots of 12¿9 m, in a

completely randomized blocks design with four replications. Evaluations included yield feed, leaf:stem ratio, weight per

stem, stem population per m2, plant population per m2 and botanical and morphological composition. Júpiter and Cuf

101 showed the highest yield (20 275 and 13 350 kg MS ha¿1). Leaf:stem ratio was higher in Cuf 101 and smaller in Júpiter. The weight per stem was higher in Júpiter and lower in Cuf 101.

Article

Medicago sativa forage yield leaf: stem relation stem weight stem population CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA CIENCIAS AGRARIAS OTRAS ESPECIALIDADES AGRARIAS

Dinámica poblacional de tallos de ovillo (Dactylis glomerata L.) solo y asociado con ballico perenne (Lolium perenne L.) y trébol blanco (Trifolium repens L.)

ADELAIDO RAFAEL ROJAS GARCIA JOEL VENTURA RIOS ALFONSO HERNANDEZ GARAY SANTIAGO JOAQUIN CANCINO MARIA DE LOS ANGELES MALDONADO PERALTA IVAN REYES VAZQUEZ (2016)

The objective of this research was to evaluate tiller population of orchard grass seeded with perennial ryegrass and white clover in different proportions and single. Treatments consisted of the associations: 20-70-10, 70-20-10, 100-00-00, 40-40-20 % of orchard grass (OG), perennial ryegrass (RG) and white clover (WT) respectively. Treatments were distributed in a randomized complete block with three replications. The association 70-20-10 of OG-RG-WT had greatest tiller density of OG with an average of 3,750 tiller m-2, and the lowest in 100-00-00 with an average of 2,400 tiller m-2 (P<0.05).

Article

Tiller population Tiller weight Fall Winter CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA CIENCIAS AGRARIAS OTRAS ESPECIALIDADES AGRARIAS