Miguel Yañez

University of Bío-Bío | UBB · Department of Statistics

Agricultural landscape heterogeneity, especially the presence of semi-natural habitats, is likely to influence bird diversity positively. In this study we tested how the diferent structural elements of the farmland mosaic affects bird diversity (rich-ness and abundance) and functional groups and their potential provision of ecosystem services in th...

The use of qualitative algorithms in images with dynamic speckle allows generating a three-dimensional intensity map, which correlates with the sample activity. Samples in an evaporation state will present temporary mobility related to their volume, which allows characterizing their topography. However, the quality of the topographic characterizati...

Este artículo tiene por objetivo presentar la experiencia de una institución de educación superior, a través de los resultados de la implementación de un modelo de dirección estratégica, investigando el impacto que presentan las etapas de análisis, formulación e implementación de este modelo para el periodo 2006-2017, 11 años. Para ello, en primer...

Objetivo: identificar los factores que impactan en la calidad de vida de las personas y su incidencia en las directrices sanitarias, a partir del área de dirección estratégica. Metodología: investigación cuantitativa, en la cual se utilizó la Encuesta Nacional de Calidad de Vida 2015-2016 e información de los servicios de salud de Chile al año 201...

Naturalized rainbow trout (Oncorhynchus mykiss) populations are an important recreational fishing resource in the Araucanian lakes of southern Chile, but few reproductive studies have been undertaken to assess their sustainability. It is important to address this issue, since this analysis may provide information for improving management activities...

Este estudio tiene dos propósitos. El primer propósito es la adaptación y validación de una Escala de Creencias de estudiantes de enseñanza secundaria. Además de proporcionar un instrumento válido y confiable, este estudio proporciona información sobre el proceso de desarrollo y validación del instrumento, que será útil para el desarrollo y validac...

In general, data regarding the mechanical properties of wood is still incomplete, mainly owing to the difficulties involved in preparing well-made standard testing samples, as well as the time-consuming evaluation tests. Therefore, the elastic constants for Pinus radiata in this paper were determined using ultrasound technology. In parallel, typica...

El presente tiene por finalidad medir el contenido de humedad en fardos de papel y cartón aplicando técnica de microonda en el espacio libre definido por la trayectoria de la onda electromagnética, particularmente en este trabajo es antena transmisora, aire, muestra, aire y antena receptora. Se realizaron a escala de laboratorio mediciones en difer...

In this article the validation results of the Online Self-regulated Learning Questionnaire (OSLQ) are presented. The adaptation was based on a method of retranslation from the original version of the document and the subsequent fulfilment of a pilot test, with a multidisciplinary sample of 238 university students. The results show a high internal c...

Objective: To evaluate the reliability and criterion validity of the Spanish version of the Meaning in Life Scale (MiLS) in Chilean chronic hemodialysis patients. Materials and methods: Cross-sectional descriptive study on a consecutive sample of 244 patients under chronic hemodialysis in the Ñuble Region Health Service. The MiLS questionnaire cons...

In this work, a system for measuring moisture content in bundles of recycled cardboard sheets using microwaves is proposed and evaluated. For the development of this system, a microwave generator and an antenna tuned in the X-band were used. The detector system used was formed by a diode array point of contact. Calibration curves of moisture conten...

We examined the individual growth of the burrowing crayfish Parastacus nicoleti (Philippi, 1882) based on a sample of 1,425 specimens. Individuals were collected monthly from November 1981 to December 1982, in the marshy wetlands of the “Pangal” homestead in Reumen, southern Chile. The Cephalothorax Length (CL) and Body Weight (BW) were recorded fo...

Background Skin pigmentation in fish is involved in various biological processes. In salmonids, the interactions of skin spottiness with biometric and reproductive parameters are mostly unknown, especially in naturalized populations influenced by different ecological factors. Objective To associate skin spottiness variation with biometric and repr...

Trichomycterus areolatus Valenciennes, 1846 is a small endemic catfish inhabiting the Andean river basins of Chile. In this study, the morphological variability of three T. areolatus populations, collected in two river basins from southern Chile, was assessed with multivariate analyses, including principal component analysis (PCA) and discriminant...

This paper presents the results of a field study on thermal comfort in school buildings in Chile, the aim of which was to determine the comfort temperature of primary school children. Results are given for twelve schools that are located in Santiago, a city with relatively low temperatures in winter and high temperatures in summer, and that are typ...

The breeding parameters of the Black-faced Ibis (Theristicus melanopis) in pastures of southern Chile between 5 July and 30 November 2014 were evaluated. Thirty active nests were monitored in an area of 31 km², using a mirror mounted on a 13-m retractable aluminum pole. Each nest was visited once a week. The Black-faced Ibis presented an asynchrono...

Samastacus spinifrons (Philippi, 1882), is the only South American parastacid that inhabits both rivers and lakes. The literature on this species reports certain morphological differences between representatives of lake and river populations. The aim of this study was to analyse the degree of differentiation of these morphological variations throug...

Dietary studies contribute to our understanding of bird ecology and are an important source of information for programs promoting the conservation of organisms. We contrasted fecal and stomach content methods of dietary analysis in the Black-faced Ibis and the Southern Lapwing, in order to evaluate the degree of sensitivity in distinguishing consum...

El presente artículo relaciona la política de endeudamiento y la teoría de agencia, pero considerando la estructura de propiedad de las empresas chilenas. El análisis econométrico se realizó mediante relaciones de causalidad y efecto, por medio de ecuaciones estructurales (structural equations models(SEM)). Los resultados reflejan un predominio de...

In this work a ranking of Chilean universities on the basis of publicly available information is developed. This ranking takes into account the multivariate character of these institutions. Also, it is noted that the results are consistent with those of a well-known international ranking that uses a different set of data, as well as with several mu...

En ecosistemas boscosos, numerosas especies de aves insectívoras usan ciertas especies de árboles como sustrato de alimentación y de nidificación. Evaluamos el uso de Pygarrhichas albogularis King, 1831 por componentes florísticos utilizados como sustrato de alimentación en un bosque nativo en el sur de Chile entre el 2009 y 2010. De 13 especies de...

Temporal variation in food availability may generate changes in the feeding strategies and trophic preferences of animals. We studied the temporal variation in feeding behavior, diet composition, and prey availability of the Black-faced Ibis (Theristicus melanopis) in pastures of southern Chile between May 1999 and January 2000. Soil core samples s...

Numerous vertebrates, and in particular birds, ingest stones (geo-gastrolites) to favour the breakdown and digestion of food in the muscular stomachs. Between 1993 and 1994 we evaluated the quantity, relative abundance and quality of autochthonous (geo-gastrolites) and allochthonous (pieces of glass) components of the grit in gizzards of black-face...

Numerous vertebrates, and in particular birds, ingest stones (geo-gastrolites) to favour the breakdown and digestion of food in the muscular stomachs. Between 1993 and 1994 we evaluated the quantity, relative abundance and quality of autochthonous (geo-gastrolites) and allochthonous (pieces of glass) components of the grit in gizzards of black-face...

This article analyzes the dividend payout ratio, remembering that Chilean firms are characterized by mandatory dividends, a strong ownership structure, growth opportunities, and institutional investors. This research was carried out for the 2001–2007 period using multiple linear regressions with variable selection by means of a stepwise approach an...

This article analyzes the dividend payout ratio, remembering that Chilean firms are characterized by mandatory dividends, a strong ownership structure, growth opportunities, and institutional investors. This research was carried out for the 2001–2007 period using multiple linear regressions with variable selection by means of a stepwise approach an...

Between September and December 1989 we analyzed the effect of flock size on feeding and vigilance behaviors of the Black-faced Ibis (Theristicus melanopis). The Black-faced Ibis formed small sized flocks during the study period. Our results show that feeding and vigilance variables were independent of flock size.

Thecamoebians are protozoans that inhabit a wide variety of terrestrial and freshwater habitats, including wet soils, lakes, saltmarshes, peatlands, etc. Their fossil shells can be recuperated from sediments in quantity sufficient to permit estimation of relative abundance. The objective of this study was to provide a first report on the distributi...

Thecamoebians are protozoans that inhabit a wide variety of terrestrial and freshwater habitats, including wet soils, lakes, saltmarshes, peatlands, etc. Their fossil shells can be recuperated from sediments in quantity sufficient to permit estimation of relative abundance. The objective of this study was to provide a first report on the distributi...

From a cognitive perspective, this article describes the reading comprehension strategies used by 5th and 8th graders when dealing with different types of written texts and the teaching practices used during the reading comprehension classes.This descriptive, exploratory study uses a quantitative and qualitative methodology as it was intended to di...