1,163 research outputs found
Recommended from our members
Double layer charging driven carbon dioxide adsorption limits the rate of electrochemical carbon dioxide reduction on Gold.
Electrochemical CO[Formula: see text] reduction is a potential route to the sustainable production of valuable fuels and chemicals. Here, we perform CO[Formula: see text] reduction experiments on Gold at neutral to acidic pH values to elucidate the long-standing controversy surrounding the rate-limiting step. We find the CO production rate to be invariant with pH on a Standard Hydrogen Electrode scale and conclude that it is limited by the CO[Formula: see text] adsorption step. We present a new multi-scale modeling scheme that integrates ab initio reaction kinetics with mass transport simulations, explicitly considering the charged electric double layer. The model reproduces the experimental CO polarization curve and reveals the rate-limiting step to be *COOH to *CO at low overpotentials, CO[Formula: see text] adsorption at intermediate ones, and CO[Formula: see text] mass transport at high overpotentials. Finally, we show the Tafel slope to arise from the electrostatic interaction between the dipole of *CO[Formula: see text] and the interfacial field. This work highlights the importance of surface charging for electrochemical kinetics and mass transport
Protocolo de telemedicina para la consulta psiquiatrica
En Colombia existen diversas poblaciones en zonas aisladas que no tienen acceso a servicios de salud
especializados, entre ellos salud mental. La telemedicina es una herramienta que permite proporcionar estos servicios, llevando
medicina especializada a un menor costo y similar calidad a través de tecnologías de la información y las comunicaciones. Como
una solución a esta problemática se propuso la estructuración de un protocolo de teleconsulta psiquiátrica y la implementación de
una aplicación web, con el fi n de proveer servicios de diagnóstico y control a pacientes con incidencia de enfermedades mentales.
Para la realización de este proyecto se analizaron lineamientos clínicos y operacionales en servicios de telepsiquiatría, se realizó
un análisis de algunas patologías de interés, se hizo un desarrollo del proceso de ingeniería de software, y por último se diseñó una
evaluación técnica y clínica de la aplicación para así obtener una retroalimentación del sistema.Colombia had are several isolated populations in areas without access to specialized health services, much less
on mental health. Telemedicine is a tool that allows to provide these services, bringing specialized medicine at lower costs and
similar quality through information and communication technologies. As a solution to this problem, a psychiatric tele-consultation
protocol and the implementation of a web application was proposed in order to provide diagnosis and follow up to patients with
mental diseases. For the development of this project; clinical and operational guidelines in Telepsychiatry services were reviewed,
diseases of interest were analyzed, a software engineering process was implemented, and fi nally a clinical and technical evaluation
were designed in order to have a feedback for the system
Selective extinction against redundant species buffers functional diversity
The extinction of species can destabilize ecological processes. A way to assess the ecological consequences of species loss is by examining changes in functional diversity. The preservation of functional diversity depends on the range of ecological roles performed by species, or functional richness, and the number of species per role, or functional redundancy. However, current knowledge is based on short timescales and an understanding of how functional diversity responds to long-term biodiversity dynamics has been limited by the availability of deep-time, trait-based data. Here, we compile an exceptional trait dataset of fossil mollusks from a 23-million-year interval in the Caribbean Sea (34,011 records, 4,422 species) and develop a novel Bayesian model of multi-trait-dependent diversification to reconstruct mollusk (1) diversity dynamics, (2) changes in functional diversity and (3) extinction selectivity over the last 23 million years. Our results identify high diversification between 23 – 5 Ma, leading to increases in both functional richness and redundancy. Conversely, over the last three million years, a period of high extinction rates resulted in the loss of 49% of species but only 3% of functional richness. Extinction rates were significantly higher in small, functionally redundant species suggesting that competition mediated the response of species to environmental change. Taken together, our results identify long-term diversification and selective extinction against redundant species that allowed functional diversity to grow over time, ultimately buffering the ecological functions of biological communities against extinction
Técnicas de protección del patrimonio arqueológico excavado
Los yacimientos arqueológicos presentan problemas para la protección ambiental de los restos que se hallan en ellos. Los materiales de las excavaciones suelen ser adobe, tapiales o piedras, materiales que sufren una gran degradación a la intemperie. Generalmente durante el proceso de degradación las construcciones pierden en primer lugar la techumbre por lo que el agua de lluvia penetra directamente sobre el interior de los yacimientos, actuando sobre revestimientos, bajorrelieves, pinturas, etc. También la cota de los restos arqueológicos suele ser inferior a los niveles actuales de las calles, por lo que el agua freática o de lluvia termina acumulándose en ellos, e incluso el viento termina transportando basuras y materiales finos sobre los restos, ayudado especialmente por los a veces maleducados visitantes
Voids by mechanical entrapment in liquid molding processes: mechanism of formation, influence in the mechanical response and reduction
Los vacíos por atrapamiento mecánico se constituyen en unos de los tipos de defectos más comunes en el procesado de Composites por moldeo líquido. Debido a la gran influencia que tienen estos vacíos en el desempeño de la pieza final, una cantidad considerable de investigaciones se han centrado en el estudio de los mecanismos de formación de los mismos, de la influencia que éstos tienen en las propiedades mecánicas del compuesto y de las estrategias para su reducción durante el procesado. El presente trabajo pretende realizar una revisión de algunas investigaciones relevantes que se han hecho en el tema de vacíos formados por atrapamiento mecánico de aire en el procesado de compuestos por LCM (Moldeo Líquido de Composites, por sus siglas en inglés), con el objetivo de generar un material de referencia dirigido a investigadores interesados en esta importante temática relacionada con las áreas del procesado y comportamiento mecánico de materiales compuestos. Serán abordados temas como: el mecanismo de formación por desbalance entre macroflujo y microflujo, y su relación con el número capilar modificado y el efecto de sumidero; los fenómenos de compresibilidad, disolución y movimiento de burbujas en preformas de doble escala; la influencia de los vacíos en las propiedades mecánicas del composite y en los mecanismos de daño; y las estrategias más comunes que pueden ser implementadas a nivel industrial para la reducción de este tipo de defectología.The voids by mechanical entrapment become as one of the most common type of defects in the liquid molding processing of composites. Because of the strong influence of those kind of voids in the general performance of the manufactured part, an important amount of researches have focused on the study of the mechanisms of formation of those voids, of the influence of the those ones on the mechanical properties of the composite and of the strategies for their reduction during the process. The present paper aims to do a review of some relevant investigations that have been done in the topic of voids caused by mechanical entrapment of air in the processing of composites by LCM (Liquid composites molding) with the purpose of generate a reference material addressed to researchers that are interested in this important subject matter related to the areas of processing and mechanical behavior of composites materials. They will be addressed some topics like: the mechanism of void formation by imbalance among macroflow and microflow and its relationship with the modified capillary number and the sink effect; the phenomena of compressibility, dissolution and mobilization of bubbles in dual-scale preforms; the influence of voids on the mechanical properties of the composites and on the damage mechanisms; and the most common strategies that can be implemented in the industry for the reduction of this sort of defects
Synthesis and Evaluation of the Fungal Activity of New Pyrazole-Carboxamides against Colletotrichum gloeosporioides
The pyrazole core has been recognized by their biological properties and included in the synthesis of modern agrochemicals. Part of these studies consists of making structural modifications to pesticides for commercial purposes to increase efficacy. In this article, we present the synthesis of four new pyrazol-4-carboxamide 8a-8d derivatives (PCD), through a four-step synthetic protocol, starting with edaravone 1 and primary amines like benzo-fused, aliphatic, and hydrazines, through a process of low environmental impact. Synthesized derivatives were evaluated against one fungal strain of Colletotrichum gloeosporioides BA3, fungus that causes several losses to farmers around the world, through in vitro sensitivity tests. The compound 8c showed better inhibiting behavior against Colletotrichum gloeosporioides BA3, inducing a lag phase of almost 2.77 days. These results were obtained via Gompertz modeling, for the first time reported for biological evaluation of pyrazole-carboxamide derivatives against Colletotrichum gloeosporioides.Fil: Gonzalez Lopez, Edwin Javier. Universidad del Atlántico; Colombia. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: León Jaramillo, Jhair Carlhino. Universidad del Atlántico; ColombiaFil: Trilleras Vásquez, Jorge Enrique. Universidad del Atlántico; ColombiaFil: Grande Tovar, Carlos D.. Universidad del Atlántico; ColombiaFil: Peralta Ruiz, Yeimmy. Universidad del Atlántico; Colombia. University Of Teramo. Faculty Of Bioscience And Technology For Food, Agriculture And Environment.; ItaliaFil: Quiroga, Jairo. Universidad del Valle; Colombi
- …