Helical propulsion in shear-thinning fluids

Swimming micro-organisms often have to propel themselves in complex non-Newtonian fluids. We carry out experiments with self-propelling helical swimmers driven by an externally rotating magnetic field in shear-thinning inelastic fluids. Similarly to swimming in a Newtonian fluid, we obtain for each fluid a locomotion speed that scales linearly with the rotation frequency of the swimmer, but with a prefactor that depends on the power index of the fluid. The fluid is seen to always increase the swimming speed of the helix, up to 50 % faster, and thus the strongest of such type reported to date. The maximum relative increase is for a fluid power index of approximately 0.6. Using simple scalings, we argue that the speed increase is not due directly to the local decrease of the flow viscosity around the helical filament, but hypothesise instead that it originates from confinement-like effect due to viscosity stratification around the swimmer.This work was funded in part by the European Union (CIG grant to E.L.). R.Z. acknowledges the financial support of the Moshinsky Foundation and the PAPIIT-DGAPA-UNAM program (grant no. IN101312)

Estudio de la viabilidad financiera para una empresa Fintech

Acorde a las nuevas tendencias a nivel mundial, en donde el uso de la tecnología ha sido clave para eficientar las comunicaciones y el comercio, se han desarrollado nuevas plataformas para administrar los recursos económicos de las personas. En México, durante el 2018 se promulgó una ley para regular este tipo de plataformas, lo que dio una mayor certeza a los posibles inversionistas para incursionar en estos mercados. En este trabajo se presenta un proyecto de inversión en una empresa de tecnología financiera que operará un monedero virtual mediante el uso de una APP, la cual tendrá diversas funcionalidades para la administración de recursos y realizar pagos, en este proyecto se analiza el entorno económico y de mercado, con lo que se realizó un estudió de la viabilidad financiera del mismo.ITESO, A.C

Reducción de la utilización de embarques expeditados en la planeación de materiales

La planeación de materiales es un área que implica una repetibilidad limitada y que enfoca su ejecución en un sistema de planeación conocido como MRP. La participación humana implica la evaluación de la salida del sistema y es la puerta a errores del proceso. El presente documento analiza el proceso de planeación de materiales con un enfoque estadístico. Basa los análisis en la búsqueda de causas que generan la necesidad de embarques expeditados. El proyecto se desarrolla mediante la aplicación de la metodología DMAIC y basa sus análisis en la varianza y la interpretación de los resultados de esta. La utilización de distintas herramientas como Diagrama de Ishikawa, Diagrama de Pareto, Histograma, Análisis de varianza, AMEF y de control, hacen del presente documento una guía para proyectos relacionados a la mejora continua. La base de la solución se dio al identificar claramente el defecto. El proceso, al no considerar defectos en pasos intermedios llevó a ignorar el verdadero comportamiento del proceso. La asociación de las variables con el defecto ayudó a aplicar mejoras temprano en el proyecto. La aplicación temprana del AMEF y su progresivo desarrollo llevó a administrar de forma correcta las soluciones y los impactos al proceso La conclusión del presente documento involucra el lado humano del proyecto, el correcto uso de habilidades interpersonales y la motivación como herramientas de apoyo para el logro del proyecto

Partition and propagate: an error derivation algorithm for the design of approximate circuits

Inexact hardware design techniques have become popular in error-tolerant systems, where energy efficiency is a primary concern. Several techniques aim to identify circuit portions that can be discarded under an error constraint, but research on systematic methods to determine such error is still at an early stage. We herein illustrate a generic, scalable algorithm that determines the influence of each circuit gate on the final output. The algorithm first partitions the graph representing the circuit, then determines the error propagation model of the resulting subgraphs. When applied to existing approximate design frameworks, our solution improves their efficiency and result quality

Plasma gradient modified scaffolds to generate a chemoattractant surface

A gradient of plasma polymerization of pyrrole was generated to model a chemoattractant surface; it was obtained by changing the polymerization time to manipulate the thickness and the deposited layer. The polymerization was generated with a power of 30W on a cylindrical vacuum reactor, the coverslip was polymerized covered by a cavity with a surface exposed of 0.7 cm every 35 min., the cells seeded were liver stellate cells (Ito); it was evaluated against a coverslip with continuous plasma polymerization of pyrrole (Ppy). The results show similar protein secretions, but cells proliferation was selective in the surface gradient regions

Relationship Between Bird Diversity and Habitat along a Pine- Oak Successional Forest in Southern Mexico

Few studies have related bird species richness and abundance with vegetation structure at different successional stages in pine-oak forests of Mexico. We studied changes in the bird community across three successional stages of pine-oak forest: early, intermediate, and mature. Also, we related bird community attributes—including generalist and specialist birds—with vegetation variables. We analyzed the vegetation and estimated bird abundances in 10-min-count periods in 10 circular plots per successional stage. We recorded a total of 71 bird species: 21 were specialists and 50 were generalists. The completeness of species richness was between 79 and 88% in the sampled habitats. Diversity profiles were consistently larger in the intermediate stage, except for its species richness that was not different between this and the early stage. We found a more richness and a higher number of individuals of generalist in the early and intermediate stages. The abundance of specialists was higher in the mature forest. An ordination analysis showed that generalists were associated to different variables. This suggests that these species can adapt to different forest conditions. Some specialist birds were more abundant in sites with high dominance of trees. Our results confirm the importance of maintaining not only mature forests but also young successional stages in order to conserve the species typical of secondary pine-oak forest bird species

Estudios etnobotánicos sobre plantas medicinales en la provincia de Camagüey (Cuba)

An ethnobotanical study has been conducted on traditional medicinal plant uses in seven communities of the Province of Camagüey, Cuba. Ethnobotanical information on 111 plant species from 96 genera and 55 families have been recorded along with 116 different vernacular names. These species are used in the treatment of 173 local health problems (mainly in respiratory, digestive, liver and gallbladder, and skin disorders). Chemistry composition of 39 species is unknown and ethnopharmacological use of 18 species has not been reported previously in the literature. The data collected in this study contribute to the pharmacological and toxicological evaluation of some of the studied species.<br><br>Como resultado del trabajo de campo realizado en siete comunidades de la provincia de Camagüey, Cuba, sobre el uso popular e indicaciones de plantas medicinales, se presenta información etnobotánica sobre 111 especies de plantas pertenecientes a 96 géneros y a 55 familias. Se obtuvieron 173 indicaciones de uso medicinal, principalmente para afecciones respiratorias, digestivas, hepatobiliares y dermatológicas. Se listaron 116 nombres vernáculos de especies vegetales. Se desconoce la composición química de 39 de las especies y de 18 no se encontraron referencias de su utilización en farmacia. Los datos empíricos obtenidos sobre usos de plantas estimularon la validación farmacológica y toxicológica de algunas de ellas

Consultoría integral en una empresa fabricante de autopartes y reparadora de motores de inyección diésel en el municipio de Guadalajara, Jalisco

ITESO, A.C