Influence of the molecular interaction in the value of molecular volume for the isotropicnematic transition of p-azoxianisol using th emodel HERSW in conjuntion with IPCM model

In this work, we analyzed the experimental pressure-temperature behavior in the Isotropic-Nematic phase transitionfor the liquid crystal p-azoxianisol at 1 atm using a development for the HERSW Conveg Peg model. Additionally, we obtained the values of the molecular volumes for the hard and attractive cores from theoretical quantum calculations at PM3, PM6 and B3LYP/6-311++G levels considering the molecular interaction among the liquidcrystals (PAA)5. We found that the best prediction for experimental data appears when the effect of the molecular interaction is considered in the volume calculation. Specifically for a/b=3.7, V0=70.86 A3 and a/bl=1.95 the best prediction was obtained

Microelectromechanical resonators based on an all polymer/carbon nanotube composite structural material

Carboxylated multi-wall carbon-nanotubes (CNTs) monolayers are integrated on microfabricated all-polymer micro-electromechanical systems (pMEMS) resonator bridges on glass substrates. The structural layer of the MEMS bridges is a multilayer blended conductive polymer based on poly(3,4-ethylenedioxythiophene):poly (styrenesulfonate) (PEDOT:PSS) to which functionalized CNT monolayers are electrostatically attached. The resonance frequency (fres) of electrostatically actuated pMEMS bridges was measured as a function of their length (32–67 lm) for different multilayer compositions. A significant increase in fres and quality factor (Q) with the addition of CNT monolayers to the PEDOT:PSS structural material is observed, demonstrating that CNT monolayers can be used to modulate pMEMS resonator properties.Peer ReviewedPostprint (published version

International positioning of Mexican mango, analysis of foreign trade competitiveness indices from 2005 to 2018

Objective: Analyze the commercial competitiveness of Mexican mango in the world market, by determining the growth rates of mango exports, imports, and production, as well as the commercial competitiveness indices. Design / methodology / approach: The production was obtained from the Agri-Food and Fisheries Information Service (SIAP), exports and imports from the International Trade Center of UNCTAD / WTO through TRADEMAP; The relative trade balance, the tradability index, the degree of export openness and the degree of import penetration were measured. Results: The relative trade balance index of Mexico, which was very close to 1. With respect to the tradability index, it was 0.2 on average. The degree of export openness was positive in all years. The import penetration degree index found that the values ​​were very close to 0. Exports grew by 97% and imports by 30%. Limitations / Implications: Statistical records for the period from 2005 to 2018 were considered; considering all the mango varieties produced and exported. Findings / conclusions: Mango is a primary product appreciated worldwide, which is why the demand for this product has been growing. Exports had a growing behavior. Imports are very few in relation to exports, in all years the positive trade balance. Mexico evidenced an increase in competitiveness at the international level.Objective: To analyze the commercial competitiveness of Mexican mango in the global market, through the determination of growth rates of mango exports, imports and production, as well as the commercial competitiveness indices. Design/Methodology/Approach: The production data were obtained from the Agrifood and Fishing Information Service (Servicio de Información Agroalimentaria y Pesquera, SIAP), and those of exports and imports from the International Trade Center of UNCTAD/OMC through TRADEMAP. The relative trade balance, the transability index, the export openness index, and the import penetration index were measured. Results: The relative trade balance in Mexico was very close to 1. The transability index had an average of 0.2. The export openness index was positive every year. The import penetration index had values very close to 0. The exports increased 97% and the imports 30%. Study Limitations/Implications: The available statistical records for the period of 2005 to 2018 were taken into account, considering all the varieties of mango produced and exported. Findings/Conclusions: Mango is a primary product highly valued globally and, therefore, demand for this product has increased. Exports had a growing behavior, while imports are very low compared to the exports. The commercial balance was positive every year. Mexico evidenced an increase of competitiveness at the international level

Weak localization and electron-electron interaction in the layered compound CuFeTe2

The study of the electrical properties of the layered compound CuFeTe2 shows that there are three well differentiated conduction regimes depending on the temperature. Below TSDW ~ 300 K the formation of a Spin Density Wave (SDW) state has been reported, in the frame of a metal to non metal transition. Below 100 K (~ TSDW/3) the behavior of the electrical resistance as a function of temperature and magnetic field is attributable to the still present not condensed electrons (quasi particles) in the SDW state. At low temperatures (1.8 - 20K), low current (< 1 mA) and magnetic eld (0<H <6 Tesla), the effects of weak localization and electronic interactions in two dimensions appear. At intermediate temperatures (20 < T < 100 K) a hopping conductivity behavior is observed

Decerebration induced by surgical transection of cerebral ganglion of crayfish

Background: Since the neural structures of the crayfish brain closely resemble their equivalent in the mammals. This can be suggested by observing the similarity that exists in the brain divided by the surgical transection of the crayfish brain in which the protocerebrum remains attached to the first two cranial nerves, findings also described by Frederic Bremer in 1935 in cats with cerebral transection.Methods: Total 11 Adult male crayfish were trained to respond with defense reflex, the animals were placed in water at 0°C, remained without any movement, and subsequently through a small incision of 3 mm in diameter in the medial antero region and dorsal cephalothorax region, a surgical section of the cerebral ganglion was performed. Immediately after surgery, metal microelectrodes were implanted to collect the activity of the photoreceptors and visual fibers.Results: Once the defense reflex begins to recover in previously decerebrated crayfish, it means that it shows signs of reconnection. The isolated protocerebrum with the deutocerebrum olfactory lobe remain alive for several days and the neuronal connections were reestablished, as measured throughout the bilateral defense activity. The defense reflex was observed in all animals and then recovered after surgery.Conclusions: The crayfish is an excellent model to work the visual activity, all coding of visual information was suppressed in de-cerebrated crayfish. The recovery of the neural disconnection is observed from 40 days, where the defence reflex appears again before visual stimuli.

Short stature, primary care approach and diagnosis

The following review article main objective seeks to provide an approach from a health care first level institution, of one of the mostfrequent queries in pediatrics and general medicine, stunted growth. The relation of consults for short stature in children is higher in boysrather than girls, but most of the times girls have more prevalence of organic diseases and growth disturbances than boys. When wereceive a patient who complains of short stature, we should ask a series of questions and take some anthropometric measures to classifythe child and determine the diagnosis. The first level doctor has to understand the meaning of these measures and determine if the child’sshort stature is whether pathological or physiological. Then the child has to be classified again, if it is a physiological short stature, heneeds to be group into genetic short stature or constitutional delay of growth and development, which constitutes by far the 80% of thecases. MÉD.UIS. 2016;29(3):73-8.Keywords: Growth Disorders. Growth and Development. Stature by Age

Wild felid species richness affected by a corridor in the Lacandona forest, Mexico

Los efectos de la presencia de un corredor en la selva Lacandona, en México, en la riqueza de especies de félidos silvestres Los félidos silvestres se encuentran entre las especies más vulnerables ante la pérdida de hábitat causada por la fragmentación de los ecosistemas. Se analizó el efecto de la presencia de un corredor estructural, definido como una franja de vegetación que conecta dos fragmentos de hábitat, en la riqueza y ocupación de félidos en tres sitios de Marqués de Comillas, en Chiapas: uno comprende dos fragmentos de bosque aislados, otro presenta un corredor estructural y el último se encuentra dentro de la reserva de la biosfera Montes Azules. Se encontraron cuatro especies en el interior de la Reserva, cinco en el corredor estructural y únicamente dos (L. pardalis y H. yagouaroundi) en los fragmentos de bosque aislados. La presencia del corredor no afectó de forma significativa a la ocupación, pero debido a la baja tasa de detección, se necesita seguir investigando para descartar diferencias. Nuestros resultados resaltan la necesidad de manejar la conectividad del hábitat en los bosques remanentes para lograr la conservación de la comunidad de félidos en Marqués de Comillas, en Chiapas, México.Los efectos de la presencia de un corredor en la selva Lacandona, en México, en la riqueza de especies de félidos silvestres Los félidos silvestres se encuentran entre las especies más vulnerables ante la pérdida de hábitat causada por la fragmentación de los ecosistemas. Se analizó el efecto de la presencia de un corredor estructural, definido como una franja de vegetación que conecta dos fragmentos de hábitat, en la riqueza y ocupación de félidos en tres sitios de Marqués de Comillas, en Chiapas: uno comprende dos fragmentos de bosque aislados, otro presenta un corredor estructural y el último se encuentra dentro de la reserva de la biosfera Montes Azules. Se encontraron cuatro especies en el interior de la Reserva, cinco en el corredor estructural y únicamente dos (L. pardalis y H. yagouaroundi) en los fragmentos de bosque aislados. La presencia del corredor no afectó de forma significativa a la ocupación, pero debido a la baja tasa de detección, se necesita seguir investigando para descartar diferencias. Nuestros resultados resaltan la necesidad de manejar la conectividad del hábitat en los bosques remanentes para lograr la conservación de la comunidad de félidos en Marqués de Comillas, en Chiapas, México.Wild felids are one of the most vulnerable species due to habitat loss caused by fragmentation of ecosystems. We analyzed the effect of a structural corridor, defined as a strip of vegetation connecting two habitat patches, on the richness and habitat occupancy of felids on three sites in Marqués de Comillas, Chiapas, one with two isolated forest patches, the second with a structural corridor, and the third inside the Montes Azules Biosphere Reserve. We found only two species (L. pardalis and H. yagouaroundi) in the isolated forest patches, five species in the structural corridor, and four species inside the Reserve. The corridor did not significantly affect occupancy, but due to the low detection rates, further investigation is needed to rule out differences. Our results highlight the need to manage habitat connectivity in the remaining forests in order to preserve the felid community of Marqués de Comillas, Chiapas, México

The Role of Developmental Assets in Gender Differences in Anxiety in Spanish Youth

Anxiety disorders are the most prevalent psychological disorders during emerging adulthood. Some consistent gender differences have been reported in anxiety with women suffering more anxiety than men, which has detrimental consequences in most life spheres in the youth and later life stages. The understanding of the development of anxiety in emerging adulthood requires a developmental perspective. The Developmental Assets Theory was postulated to describe the individual and the contextual resources which may foster positive youth development and mental health. The present study aims to analyze to what extent the gender differences in anxiety may be partly explained by gender differences in developmental assets. For this purpose, a cross-sectional study was conducted in which a sample of 1,044 youths (75.5% women; age range = 18–28; M age = 20.47, SD = 3.08) enrolled in 11 universities from different regions in Spain filled in self-report measures of developmental assets and anxiety symptoms. The participants completed an online survey with the scales, Developmental Assets Profile developed by the Search Institute (1) and Generalized Anxiety Disorder-7 (GAD-7) (2). The results showed more anxiety in the female subsample (at both the symptoms and clinical levels). Some gender differences in developmental assets were also observed. A partial mediation model, based on regression analyses, indicated that gender differences in anxiety were partly explained by gender differences in developmental assets. Thus, higher anxiety in the women was partly due to lower scores in positive identity and higher scores in positive values. These results suggested the need to design programs to prevent anxiety with specific measures for women youth to nurture positive identity and promote strengths and coping skills that allow them to get the benefits of well-being derived from positive values, thus, preventing worry and stress overload, which may lead to anxiety.This research received funding from Research, Development and Innovation Projects of European Regional Development Fund in Andalusia 2014–2020. Grant number UHU-1259711, awarded to the first and last authors

Nivel de formación sobre sexualidad humana en estudiantes del primer ciclo en la Universidad Católica Santo Toribio de Mogrovejo, año 2010

La sexualidad humana es un concepto que abarca distintos ámbitos. Generalmente la sociedad tiende a relacionarlo con la parte reproductiva, sin embargo no solo atañe a lo sexual propiamente dicho, pues también comprende a la parte afectiva, de allí que se hable de una salud sexual y afectiva. El presente trabajo tiene como finalidad determinar el nivel de formación sobre sexualidad humana en estudiantes del primer ciclo en la Universidad Católica Santo Toribio de Mogrovejo, año 2010. Para la realización de la investigación se empleó un estudio descriptivo primario de tipo transversal, utilizándose el consentimiento informado para proceder a la encuesta elaborada por los autores en conjunto con un experto en el tema, siendo ésta revisada por dos sacerdotes y una psicóloga, y previamente empleada en prueba piloto. Ésta se aplicó en el muestreo obtenido estadísticamente de una población total de 1496 estudiantes 2010-I. Resultando los sujetos a investigar 424 estudiantes, considerados según estratos según facultad: ciencias empresariales, derecho, humanidades, ingeniería y medicina. Sin embargo la muestra de estudio se incrementó durante el proceso, haciendo un total de 439 estudiantes. Para el análisis de los datos se empleó tablas de frecuencias, diagramas de barras, diagrama de sectores y el programa Estadístico Excel. Se concluyó que de los 439 estudiantes del primer ciclo de USAT 2010-I entrevistados: el 19% presentó nivel alto de formación sobre sexualidad humana; el 62%, predominante, presentó un nivel medio, mientras que el restante, 18%, presentó nivel bajo