In vitro comparative study on the friction of stainless steel wires with and without Orthospeed (JAL 90458) on an inclined plane

Background: During the treatment of orthodontics, in the mechanics of slide, there takes place friction, which they reduce the slide of the arch across bracket. Therefore, clinical there takes place an increase of the time of treatment. There are different the technologies that try to reduce this friction, as the self-ligating braces. The purpose of this study was to research the in vitro behavior of JAL 90458 as a buffering agent which reduces friction between brackets and stainless steel arch wires of different cross sections and sizes. Material and Methods: Three types of stainless steel wires with different cross sections and three types of ligatures were used with and without JAL 90458 to measure the friction according to the time and distance traveled by the brackets on an inclined plane with two angulations. The Kruskal-Wallis one-way analysis of variance by ranks was applied to determine the degree of friction between the group using and the group not using the product ( P ≤ .05). Results: Separate analysis of the arch wires, ligatures and angulation with and without the compound revealed statistically significant differences between the groups, showing that friction was reduced significantly when JAL 90458 was used ( P ≤ .01). The 0.021x0.025” arch wires and the arch wires attached using elastic ligatures produce the least resistance to sliding among all of those analyzed when the product was not used ( P ≤ .05). Conclusions: The results show that JAL 90458 reduces friction independently of arch wire cross section, type of ligature and angulation of the measuring instrument

Use of Pulse Pressure Variation as Predictor of Fluid Responsiveness in Patients Ventilated With Low Tidal Volume: A Systematic Review and Meta-Analysis

Introduction: Pulse pressure variation (PPV) has been shown to be useful to predict fluid responsiveness in patients ventilated at tidal volume (Vt) >8 mL kg−1. Nevertheless, most conditions in critical care force to use lower Vt. Thus, we sought to evaluate the operative performance of PPV when a Vt ⩽8 mL kg−1 is used during mechanical ventilation support. Methods: We searched PubMed and Embase databases for articles evaluating the operative performance of PPV as a predictor of fluid responsiveness in critical care and perioperative adult patients ventilated with tidal volume ⩽8 mL kg−1 without respiratory effort and arrhythmias, between January 1990 and January 2019. We included cohort and cross-sectional studies. Two authors performed an Independently selection using predefined terms of search. The fitted data of sensitivity, specificity, and area under the curve (AUC) were assessed by bivariate and hierarchical analyses. Results: We retrieved 19 trials with a total of 777 patients and a total of 935 fluid challenges. The fitted sensitivity of PPV to predict fluid responsiveness during mechanical ventilation at Vt ⩽8 mL kg−1 was 0.65 (95% confidence interval [CI]: 0.57-0.73), the specificity was 0.79 (95% CI: 0.73-0.84), and the AUC was 0.75. The diagnostic odds ratio was 5.5 (95% CI: 3.08-10.01, P < .001) by the random-effects model. Conclusions: Pulse pressure variation shows a fair operative performance as a predictor of fluid responsiveness in critical care and perioperative patients ventilated with a tidal volume ⩽8 mL kg−1 without respiratory effort and arrhythmias

The mapping of spanish social psychology through its conferences: a bibliometric perspective

This study of papers gathered from the proceedings presented at Spanish social psychology conferences explores the use of bibliometrics for studying scientific disciplines. A reference database of all the papers included in the conference proceedings of events held from 1983 to 2000 was generated and classified by thematic area, paper type and author institutional affiliation. The references were laid out on contingency tables and mapped with correspondence analysis. The results show that there is a growing number of co-authored papers and a predominance of empirical over theoretical paper types. Some institutions have a higher concentration of theoretical papers while others work mostly in the areas of organizational and health psychology. In terms of empirical papers, there is a tendency towards generating more qualitative-based studies over the span of time captured by this work. There are also a number of papers written about such areas as cultural psychology that points to the emergence of an interest in critical social psychology. Concluding remarks underline the role of conferences and scientific meetings as an important indicator of the dynamic development of a scientific discipline.Este estudio de trabajos recogidos de las actas presentadas en conferencias de Psicología Social española explora el uso de los bibliométricos para estudiar las disciplinas científicas. Se generó y se clasificó por área temática, tipo de trabajo y afiliación institucional del autor una base de datos de referencia de todos los trabajos incluidos en las actas de las conferencias de eventos celebradas desde 1983 hasta 2000. Se ordenaron las referencias en tablas de contingencia correlacionadas con análisis de correspondencia. Los resultados muestran que el número de trabajos con co-autores incrementa y hay predominancia de trabajos de tipo empírico sobre teórico. Algunas instituciones tienen mayor concentración de trabajos teóricos, mientras que otras trabajan más en las áreas de la psicología organizacional y de la salud. En términos de trabajos empíricos, hay una tendencia hacia la generación de estudios con más base cualitativa en el intervalo temporal captado por este trabajo. También hay un número de trabajos escritos sobre áreas tales como la psicología cultural, lo que indica la emergencia de un interés en la psicología social crítica. Los comentarios finales subrayan el papel de las conferencias y encuentros científicos como un indicador importante del desarrollo dinámico de una disciplina científica

Celda de combustible SOFC: uso de biogás de rellenos sanitarios para la generación de energía eléctrica

In this study, it was analyzed how it affects the serious problem of current pollution in water, air and soil due to anthropogenic activities in the city of Morelia, Michoacán. An analysis of the current state of fuel cell technology has been carried out, identifying the solid oxide fuel cell (SOFC) as an excellent candidate. This would allow determining the possibility of using a SOFC as a generator of electric energy from biogas composed mainly of methane and carbon dioxide as fuel. By generating electricity from these gases that come from landfills, it is intended to establish an energy optimization and sustainable process.En este estudio, se analizó como afecta el grave problema de la contaminación actual en agua, aire y suelo debido a actividades antropogénicas de la ciudad de Morelia, Michoacán. Se ha realizado un análisis del estado actual de la tecnología de celdas de combustible, identificándose a la celda de combustible de óxido sólido (SOFC), como un excelente candidato. Esto permitiría determinar la posibilidad de utilizar una celda SOFC como generador de energía eléctrica a partir de biogás compuesto principalmente de metano y bióxido de carbono como combustible. Al generar energía eléctrica a partir de estos gases que provienen de rellenos sanitarios, se pretende establecer un proceso de optimización energética y sustentable

Managua Salsa City de Franz Galich

La presente es una investigación literaria que esboza un breve recorrido histórico y sociopolítico desde principios del siglo XX con la injerencia extranjera en Nicaragua, la instauración y las pugnas entre somocistas y sandinistas, hasta el fin de la guerra en 1990. El eje temático principal es la posguerra. Un entramado de problemáticas sociales como la violencia, el crimen organizado, el desempleo y la pobreza, que desenfundan en los individuos un sentimiento de desencanto generalizado hacia los proyectos revolucionarios que habían prometido velar por la seguridad, la igualdad y el cambio hacia una sociedad más prospera. El análisis narratológico retoma los aportes de autores como Beatriz Cortéz, José Luis Escamilla, Werner Mackenbach, José María Pozuelo Yvancos y otros. El cual se organiza según las instancias narrativas, del relato, la narración y la historia, incorporando los elementos concernientes a cada una de ellas siguiendo la línea del tradicionalismo narratológico de Tzvetan Todorov y A.J. Greimas. Finalmente, el análisis semántico se enfoca en los signos y símbolos. Palabras clave: Franz Galich, Novela de posguerra ; Estética del Cinismo ; Contexto de posguerra centroamericana ; Posmodernidad

Improving construction processes of concrete building structures using load limiters on shores

This paper analyses the redistribution of maximum loads using a system of load limiters on shores in which the limiters yield at a given load and thus reduce the maximum load absorbed by the shores. For this analysis a finite element modelling (FEM) of an experimental building was developed in which load limiters had been fitted to the shores to restrict their maximum load to a given value. This was designed to: (a) optimise slab construction costs by using shores of lower load-bearing capacities, (b) improve safety during the construction of consecutive concrete slab floors by reducing maximum loads and redistributing loads amongst the shores; and (c) increase structural efficiency by more efficient use of the materials employed due to load redistribution. It has been estimated that using load limiters in this way can reduce total shoring costs in a building project by between 30% and 40%.The authors would like to express their gratitude to the Universitat Politecnica de Valencia for funding this research project (PAID-06-11) and also to the Encofrados J. Alsina Company for their invaluable cooperation.Buitrago Moreno, M.; Alvarado Vargas, YA.; Adam Martínez, JM.; Calderón García, PA.; Gasch, I.; Moragues, JJ. (2015). Improving construction processes of concrete building structures using load limiters on shores. Engineering Structures. 100:104-115. doi:10.1016/j.engstruct.2015.06.007S10411510

Hidrodesoxigenación catalítica: uso de compuestos derivados de biomasa para la generación de biocombustibles

This study examined the importance of the hydrodeoxygenation (HDO) process, which allows us to obtain molecules with the necessary calorific potential to be useful as biofuels, an example of which is the phenol molecule, predominant in the mixtures remaining from cellulose liquefaction processes. The process was standardized using NiMoW trimetallic catalysts supported on Al2O3 which is based on two routes; the direct hydrogenation of the aromatic ring, followed by the cleavage of the Csp3-O bond and the direct cleavage by deoxygenation of the Csp2-O bond of the molecule, both routes are carried out simultaneously generating as reaction products: molecules such as: benzene, cyclohexane, cyclohexene, methylcyclopentane, cilohexanone and cyclohexanol. This type of catalysts present conversions of up to 92% of oxygenated molecules such as phenol, showing desirable textural properties (surface area, distribution and pore size), which allows a greater interaction in the reaction mixture, favoring the conversion, providing a promising alternative for purification processes of oxygenated molecules provided by nature for the optimization of obtaining biofuels.En este estudio se examinó la importancia del proceso de hidrodesoxigenación (HDO), el cual nos permite obtener moléculas con el potencial calorífico necesario para ser útiles como biocombustibles, ejemplo de ello es la molécula de fenol, predominante en las mezclas remanentes de procesos de licuefacción celulósica. Se estandarizó el proceso utilizando catalizadores trimetálicos NiMoW soportados en Al2O3 el cual se basa en dos vías; la hidrogenación directa del anillo aromático, seguido de la escisión del enlace Csp3-O y la escisión directa por desoxigenación del enlace Csp2-O de la molécula, ambas rutas se llevan a cabo simultáneamente generando como productos de reacción: moléculas como: benceno, ciclohexano, ciclohexeno, metilciclopentano, cilohexanona y ciclohexanol. Este tipo de catalizadores presentan una conversión de hasta el 92% de moléculas oxigenadas como el fenol, mostrando propiedades texturales deseables (área superficial, distribución y tamaño de poro), lo cual permite una mayor interacción en la mezcla de reacción, favoreciendo la conversión, proporcionando una alternativa prometedora para procesos de purificación de moléculas oxigenadas que provee la naturaleza para la optimización de obtención de biocombustibles. &nbsp

ROBOT DE DOS GRADOS DE LIBERTAR COMO UNA PLATAFORMA EDUCATIVA PARA ROBÓTICA (A 2-DOF ROBOT AS AN EDUCATIONAL PLATFORM FOR ROBOTICS)

En este trabajo se presenta el inicio del desarrollo de una plataforma de apoyo educativo para la materia de robótica. La plataforma presentada está basada en LabVIEW y cuenta con un robot planar de 2 grados de libertad, construido con actuadores Dynamixel, los cuales son parte de un kit de robótica de Robotis. El objetivo de la plataforma desarrollada es ofrecer al docente un apoyo didáctico en áreas temáticas de la robótica, tales como el cálculo e implementación de la cinemática directa e inversa, planeación de trayectorias y control, en un esfuerzo por motivar al estudiante con un resultado práctico de la teoría revisada en la clase.Palabra(s) Clave: LabVIEW, robótica educativa, robot planar.  AbstractThis work presents the beginning of an educational platform for the robotics subject. The presented platform is based in a 2-dof robot controlled with LabVIEW; the 2-dof robot is built with Dynamixel actuators, which are part from a robotics kit of Robotis. The goal of the developed platform is to offer an educational support in the topics reviewed as part of the robotics subject such as direct and inverse kinematics, planning of trajectories and control, this as an effort to encourage the students with a direct application of the reviewed topics during a robotics’ class.Keywords: 2 dof robot, educational robotics, LabVIEW

Confined benzene within InOF-1: Contrasting CO2 and SO2 capture behaviours

The confinement of small amounts of benzene in InOF-1 (Bz@InOF-1) shows a contradictory behavior in the capture of CO2 and SO2. While the capture of CO2 is increased 1.6 times, compared to the pristine material, the capture of SO2 shows a considerable decrease. To elucidate these behaviors, the interactions of CO2 and SO2 with Bz@InOF-1 were studied by DFT periodical calculations postulating a plausible explanation: (a) in the case of benzene and CO2, these molecules do not compete for the preferential adsorption sites within InOF-1, providing a cooperative CO2 capture enhancement and (b) benzene and SO2 strongly compete for these preferential adsorption sites inside the MOF material, reducing the total SO2 capture