2,547 research outputs found
Is undergraduate programme accreditation influenced by educational public policy quality indicators? An exploratory study of the Chilean Higher Education quality assurance system
In Chile, as well as in most of Latin America, public policies for higher education have recently adopted a focus on quality assurance and accreditation systems. Uncertainty, however, still exists in terms of the quality assurance consistency in the current Chilean accreditation system, especially in terms of the relation between public policy quality indicators for higher education and their relation to accreditation outcomes. Therefore, the aim of this study was to make a first explorative attempt to investigate the relationships between these indicators and the results of undergraduate programme accreditation. We hypothesised that the public policy quality indicators of first-year drop-out rate, employment at graduation and ratio of actual to expected time to graduation would be strongly correlated to undergraduate programme accreditation as well as largely explaining its accreditation-year variance. By means of correlation and multiple regression analyses, we found small-sized associations, being first-year drop-out the only significant predictor of programme accreditation, explaining a 9.4% of its variance. These results raise questions regarding the consistency between the aims of public policy for higher education and the current accreditation system. This study should be of value to policy makers, managers and curriculum developers in terms of this initial analysis of the consistency between quality indicators and the accreditation system. Further research is necessary to make a systematic and in-depth assessment of the impact of quality assurance mechanisms to provide better rationale for making important decisions such as when defining the characteristics of the accrediting institutions as well as for establishing effective ways to achieve the proposed public policy objectives
Detección de fisuras en placas de Aluminio mediante ultrasonidos utilizando ondas Lamb
By the emerging application of ultrasound in different industrial fields, it is necessary to develop inspection procedures to detect the presence of discontinuities that affect the properties of these materials. The development of this project is expects a study using the technique of ultrasonic nondestructive testing that allows detect failures in plates of Aluminium through the utilization of Lamb waves. ___________________________Debido al gran crecimiento de los ultrasonidos en diferentes campos de la industria, es necesario estudiar e investigar nuevos procedimientos de inspección para detectar la presencia de discontinuidades que afectan a las propiedades de los materiales. Durante el desarrollo de este proyecto se pretende realizar un estudio mediante una técnica de ensayos no destructivos por ultrasonidos no demasiado conocida como son las ondas Lamb, que permite detectar las fisuras en las placas de Aluminio.Ingeniería Industria
Evaluación de los factores de riesgo en los activos de renta variable que conforman el índice S&P MILA 40: aplicación del modelo de tres factores de Fama y French en el periodo 2009-2013
El presente artículo de investigación estima los factores de riesgo en los activos de renta variable que conforman el índice S&P MILA 40, a través de la aplicación del modelo de tres factores de Fama y French en el periodo 2009- 2013. Este modelo, a partir de la evaluación de componentes microeconómicos, busca identificar las variables que potencialmente pueden tener influencia en la estimación de retornos de los activos y, de esta manera, lograr generar mayores niveles de información al mercado y a los agentes para la toma de decisiones de inversión. Luego de realizar los procedimientos, se puede establecer que, para los activos seleccionados, las carteras de menor capitalización generan los mayores rendimientos para los inversionistas, dentro las cuales se destaca la participación de manera ponderada de activos del mercado peruano; estos, por la naturaleza de las empresas y las condiciones de la economía, permitieron el surgimiento y la potencialización de activos de inversión que generan mayores condiciones de rentabilidad.The present research article considers risk factors in variable income assets that make up the S&P MILA 40 index, through applying the Fama and French three factor model in the period 2009-2013. This model, based on the evaluation of microeconomic components, seeks to identify variables that can potentially influence the estimation of asset returns and, in this way, generate higher levels of information for the market and agents to make investment decisions. After performing these procedures, it can be established that, for the selected assets, lower capitalization portfolios generate the highest returns for investors, in which the weighted participation of Peruvian market assets stands out. Given the nature of the companies and conditions of the economy, these allowed for the emergence and strengthening of investment assets that generated better conditions of profitability
Field Fluctuations and Casimir Energy of 1D-Fermions
Producción CientíficaWe investigate the self-adjoint extensions of the Dirac operator of a massive one-dimensional
field of mass m confined in a finite filament of length L. We compute the spectrum of vacuum
fluctuations of the Dirac field under the most general dispersionless boundary conditions. We identify
its edge states in the mass gap within a set of values of the boundary parameters, and compute the Casimir energy of the discrete normal modes. Two limit cases are considered, namely, that of light fermions with mL 1, and that of heavy fermions for which mL 1. It is found that both positive and negative energies are obtained for different sets of values of the boundary parameters. As a consequence of our calculation we demonstrate that the sign of the quantum vacuum energy is not
fixed for exchange-symmetric plates (parity-invariant configurations), unlike for electromagnetic and
scalar fields.Ministerio de Economía, Industria y Competitividad (grant MTM2014-57129-C2-1-P)Junta de Castilla y León - Fondo Europeo de Desarrollo Regional (grants VA057U16 and BU229P18)Junta de Castilla y León (grant VA137G18
Metropolización y región periurbana en Morelos
Actualmente los estudios regionales enfrentan el desafío de analizar de manera crítica los acontecimientos que ocurren en las zonas urbanas y metropolitanas, poniendo atención a procesos que hoy han modificado la forma tradicional de entender las nuevas relaciones territoriales de escala local y regional. En este contexto la presente investigación se aboca a estudiar los antecedentes del proceso de urbanización y metropolización en el estado de Morelos. Se expone como Cuernavaca en el noroeste, Cuautla en noreste y Jojutla en el sur, han tenido cada una de ellas su propios procesos de urbanización, pero guardando relación entre las tres, pues existe un flujo importante de migrantes pendulares que se mueven diariamente desde diferentes localidades, lo que ha dado lugar a la conformación de una gran región rururbana que abarca prácticamente todo el estado. La investigación aborda la modificación de la estructura de la población, pasando de un tipo rural a otro de carácter urbano; esto ha conllevado a la modificación en los patrones de ocupación de la de la población rural que está participando cada vez más en las actividades industriales, del comercio y los servicios. Para conocer a profundidad las modificaciones se aplicaron dos modelos, el gravitacional y una matriz de origen/destino, en el se utilizaron datos estadísticos de viajes por motivos de trabajo. De lo anterior se pudo conocer que el crecimiento de las zonas metropolitanas de Cuernavaca y Cuautla las ha llevado a unirse por medio de Yautepec. En tanto por el sur la tendencia es a unirse funcionalmente con Jojutla por medio de la carretera libre Jiutepec – Emiliano Zapata en donde se localizan fraccionamientos de interés social, industrias y empresas de comercio y servicios
La reticencia de los agricultores familiares respecto a su inserción en la economía formal
[EN] Informal economy is particularly prevalent in small-scale farming, yet little attention has been paid to it so far. This article aims to contribute to a further understanding of this phenomenon. A survey of family farmers located in the Metropolitan Region of Santiago, Chile, was conducted. The data collected were processed using descriptive and multivariate techniques, factor and cluster analysis. Results show that farmers perceive formalization as a complex process which entails unpleasant obligations, and that they do not consider it necessary. There are some distinctions, however, that allow two clusters to be identified: “Favorable” (18.82 %) and “Reluctant” (81.18 %).[ES] La economía informal está especialmente presente en la pequeña agricultura, aunque se le ha prestado poca atención. El presente artículo tiene como propósito contribuir a un mayor entendimiento al respecto. Para ello, se llevó a cabo una encuesta a agricultores familiares de la Región Metropolitana de Santiago, Chile. La información recolectada fue analizada mediante técnicas descriptivas y multivariantes. Los resultados muestran que los agricultores perciben la formalización como un proceso complejo que conlleva obligaciones no deseadas, así como que no la consideran necesaria. Sin embargo, existen algunas diferencias, las cuales permiten identificar dos grupos: “Favorables” (18.82 %) y “Reacios” (81.18 %).Boza, S.; Mora, M.; Osorio, F.; Muñoz, J. (2019). Family farmers’ reluctance toward incorporating into the formal economy. Economía Agraria y Recursos Naturales - Agricultural and Resource Economics. 18(2):75-92. doi:10.7201/earn.2018.02.04SWORD759218
Computational Tradeoffs of Optimization-Based Bound Tightening in ReLU Networks
The use of Mixed-Integer Linear Programming (MILP) models to represent neural
networks with Rectified Linear Unit (ReLU) activations has become increasingly
widespread in the last decade. This has enabled the use of MILP technology to
test-or stress-their behavior, to adversarially improve their training, and to
embed them in optimization models leveraging their predictive power. Many of
these MILP models rely on activation bounds. That is, bounds on the input
values of each neuron. In this work, we explore the tradeoff between the
tightness of these bounds and the computational effort of solving the resulting
MILP models. We provide guidelines for implementing these models based on the
impact of network structure, regularization, and rounding.Comment: 8 pages, 4 figure
Metal-responsive RNA polymerase extracytoplasmic function (ECF) sigma factors
In order to survive, bacteria must adapt to multiple
fluctuations in their environment, including coping
with changes in metal concentrations. Many metals
are essential for viability, since they act as cofactors
of indispensable enzymes. But on the other
hand, they are potentially toxic because they generate
reactive oxygen species or displace other metals
from proteins, turning them inactive. This dual
effect of metals forces cells to maintain homeostasis
using a variety of systems to import and export
them. These systems are usually inducible, and
their expression is regulated by metal sensors and
signal-transduction mechanisms, one of which is
mediated by extracytoplasmic function (ECF) sigma
factors. In this review, we have focused on the metalresponsive
ECF sigma factors, several of which are
activated by iron depletion (FecI, FpvI and PvdS),
while others are activated by excess of metals such
as nickel and cobalt (CnrH), copper (CarQ and CorE)
or cadmium and zinc (CorE2). We focus particularly
on their physiological roles, mechanisms of action
and signal transduction pathways.This work has been supported by the Spanish Government,
grant BFU2016-75425-P to Aurelio Moraleda-Muñoz (70%
funded by FEDER)
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