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Search Results: 1 - 10 of 355530 matches for " D. de la Fuente "
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Assessing Students’ Difficulties with Conditional Probability and Bayesian Reasoning
Carmen Díaz,Inmaculada de la Fuente
International Electronic Journal of Mathematics Education , 2007,
Abstract: In this paper we first describe the process of building a questionnaire directed to globally assess formal understanding of conditional probability and the psychological biases related to this concept. We then present results from applying the questionnaire to a sample of 414 students, after they had been taught the topic. Finally, we use Factor Analysis to show that formal knowledge of conditional probability in these students was unrelated to the different biases in conditional probability reasoning. These biases also appeared unrelated in our sample. We conclude with some recommendations about how to improve the teaching of conditional probability.
Gravitational interactions between globular and open clusters: an introduction
R. de la Fuente Marcos,C. de la Fuente Marcos,D. Reilly
Physics , 2013, DOI: 10.1007/s10509-013-1635-7
Abstract: Historically, it has been assumed that globular and open clusters never interact. However, recent evidence suggests that: globular clusters passing through the disk may be able to perturb giant molecular clouds (GMCs) triggering formation of open clusters and some old open clusters may be linked to accreted globulars. Here, we further explore the existence of possible dynamical connections between globular and open clusters, and realize that the most obvious link must be in the form of gravitational interactions. If open clusters are born out of GMCs, they have to move in similar orbits. If we accept that globulars can interact with GMCs, triggering star formation, it follows that globular and open clusters must also interact. Consistently, theoretical arguments as well as observational evidence, show that globular and open clusters certainly are interacting populations and their interactions are far more common than usually thought, especially for objects part of the bulge/disk. Monte Carlo calculations confirm that conclusion. Globular clusters seem capable of not only inducing formation of open clusters but, more often, their demise. Relatively frequent high speed cluster encounters or cluster harassment may also cause, on the long-term, slow erosion and tidal truncation on the globulars involved. The disputed object FSR 1767 (2MASS-GC04) may be, statistically speaking, the best example of an ongoing interaction.
An Econometric Analysis for the Behavior of the Bid-Ask Spread  [PDF]
H. de la Fuente-Mella, R. Campos-Espinoza, B. Silva-Palavecinos, D. Cademartori-Rosso
Open Journal of Social Sciences (JSS) , 2013, DOI: 10.4236/jss.2013.17001
Abstract:

Information asymmetries are an important element in the functioning of capital markets. An indirect means of measuring information asymmetry is through the spread of stock prices. The purpose of this paper is to identify the explanatory variables and the determinants of the bid-ask spread and to quantify the influence that the actors involved in the brokering of publically offered securities may have over the spread. The methodology used to model the time series for each of the analyzed companies is based on a time series from each of the observed econometric multivariate processes. The analysis shows a significantly negative relationship between the spread and the market-maker size, calculated in terms of both the equity and the stock portfolio; likewise, activity is measured by observing the amount offered for purchase and/or sale.

Looking Back on Contributions in the Field of Atmospheric Corrosion Offered by the MICAT Ibero-American Testing Network
M. Morcillo,B. Chico,D. de la Fuente,J. Simancas
International Journal of Corrosion , 2012, DOI: 10.1155/2012/824365
Abstract: The Ibero-American Map of Atmospheric Corrosiveness (MICAT) project was set up in 1988 sponsored by the International Ibero-American programme “Science and Technology for Development (CYTED)” and ended in 1994 after six years of activities. Fourteen countries were involved in this project: Argentina, Brazil, Chile, Colombia, Costa Rica, Cuba, Ecuador, Mexico, Panama, Peru, Portugal, Spain, Uruguay, and Venezuela. Research was conducted both at laboratories and in a network of 75 atmospheric exposure test sites throughout the Ibero-American region, thus considering a broad spectrum of climatological and pollution conditions. Although with its own peculiarities, the project basically followed the outline of the ISOCORRAG and ICP/UNECE projects, with the aim of a desirable link between the three projects. This paper summarizes the results obtained in the MICAT project for mild steel, zinc, copper, and aluminum specimens exposed for one year in different rural, urban, and marine atmospheres in the Ibero-American region. Complementary morphological and chemical studies were carried out using scanning electron microscopy (SEM) coupled with energy dispersive spectrometry (EDS), X-ray diffraction (XRD), and fourier transform infrared Spectroscopy (FTIR) techniques, in order to correlate climatic and atmospheric conditions and properties of the corrosion products. 1. Introduction During the 2nd Ibero-American Congress on Corrosion and Protection held in Maracaibo (Venezuela) in September 1986, a round-table was organized to discuss the idea of an Ibero-American Map of Atmospheric Corrosion (MICAT). Representatives of the countries present at the meeting expressed their interest in participating in such a project. Moves were then made to include this proposal in the Ibero-American Programme Science and Technology for Development (CYTED). A year later, in January 1988, the Technical and Managing Council of CYTED, gathered in Havana (Cuba), decided to approve the inclusion of the MICAT study into the CYTED Programme. The primary aims of the MICAT study were [1, 2] as follows.(1)To improve knowledge of the process of atmospheric corrosion in various climatic regions of Iberoamerica.(2)By means of statistical treatment of the results to obtain mathematical expressions of the estimation of atmospheric corrosion as a function of climatic and pollution parameters.(3)No less important was the objective of promoting international cooperation. In this respect, the building of bridges of understanding and the establishing of Ibero-American research groups have been
Osteoporosis: una patología con afectación personal, familiar, laboral y social
Mira Ferrer,Luz Ma; Fuente Díez,Elena de la;
Medicina y Seguridad del Trabajo , 2007, DOI: 10.4321/S0465-546X2007000100008
Abstract: the osteoporosis and the osteoporotic fracture represent a prevalent disease and one of the main problem in the developed countries. the european and spanish population are going to be older from the last century and the osteoporosis is growing up. in other hand, usually, the disease affect people at the 40 th decade of life when they are working population in active labour life period, so the osteoporosis is an important cause of absenteeism, and consistently, the osteoporosis means a high economic, social, family, sanitary and labour cost. one of the main effectives activities in the control of the disease are the instauration of prevention programs guided to target populations. an effective program of early diagnosis and treatment of osteoporosis is the gold standard method to attend correctly this "silent illness". the roads points of actuation are related with an early detection of the risks factor in each patient before the fracture and others complications takes place. them, we must recommend healthful habits of life to avoid the appearance of osteoporosis and osteoporosis fracture. the services of prevention of labour risk have a privileged position to develop this prevention programes.
The effects of soluble salts at the metal/paint interface: advances in knowledge
Fuente,D. de la; Chico,B.; Morcillo,M.;
Portugaliae Electrochimica Acta , 2006,
Abstract: the presence of soluble salts (particularly sulphates and chlorides) at the metal/paint interface is known to have a detrimental effect on the integrity of most paint systems. though this is a long-standing problem, it has recently come to receive greater attention from the protective coatings industry. international standards organization (iso) has for some time been trying to develop a standard about guidance levels for water-soluble salt contamination before the application of paints and related products. in the paper the following points are reviewed: degradation mechanisms, nature and sources of soluble salts, their distribution on the metallic surface, the joint action of chlorides and sulphates, the effect of the joint presence of rust, new methodologies for sample preparation with known levels of soluble salts, measuring soluble salts, establishment of threshold levels, removal of salts and new suitable coating systems for applying on substrates contaminated with soluble salts.
The effects of soluble salts at the metal/paint interface: advances in knowledge
D. de la Fuente,B. Chico,M. Morcillo
Portugaliae Electrochimica Acta , 2006,
Abstract: The presence of soluble salts (particularly sulphates and chlorides) at the metal/paint interface is known to have a detrimental effect on the integrity of most paint systems. Though this is a long-standing problem, it has recently come to receive greater attention from the protective coatings industry. International Standards Organization (ISO) has for some time been trying to develop a standard about guidance levels for water-soluble salt contamination before the application of paints and related products. In the paper the following points are reviewed: degradation mechanisms, nature and sources of soluble salts, their distribution on the metallic surface, the joint action of chlorides and sulphates, the effect of the joint presence of rust, new methodologies for sample preparation with known levels of soluble salts, measuring soluble salts, establishment of threshold levels, removal of salts and new suitable coating systems for applying on substrates contaminated with soluble salts.
Osteoporosis: una patología con afectación personal, familiar, laboral y social
Luz Ma Mira Ferrer,Elena de la Fuente Díez
Medicina y Seguridad del Trabajo , 2007,
Abstract: La osteoporsis y las fracturas osteoporóticas son un importante problema en nuestra sociedad debido a su gran frecuencia. En nuestro siglo la población europea y espa ola está envejeciendo y la prevalencia de la osteoporosis va en aumento. Por otro lado la osteoporosis afecta a la población con edad a partir de la década de los 40, es decir durante la vida laboral activa, así que representa una importante causa de absentismo laboral. Esto produce un alto coste económico, social, familiar y sanitario. Es interesante promover programas de detección para disminuir estas consecuencias. Un programa efectivo de diagnóstico y tratamiento de la osteoporosis es el método "gold tandard" para el manejo de esta "enfermedad silenciosa". La detección precoz de los factores de riesgo de esta enfermedad es el punto clave de actuación. Debemos recomendar hábitos de vida saludables para evitar la aparición de la osteoporosis y de las fracturas osteoporóticas. Los Servicios de Prevención de Riesgos Laborales tienen una posición privilegiada para instaurar actividades en este sentido. The osteoporosis and the osteoporotic fracture represent a prevalent disease and one of the main problem in the developed countries. The European and Spanish population are going to be older from the last century and the osteoporosis is growing up. In other hand, usually, the disease affect people at the 40 th decade of life when they are working population in active labour life period, so the osteoporosis is an important cause of absenteeism, and consistently, the osteoporosis means a high economic, social, family, sanitary and labour cost. One of the main effectives activities in the control of the disease are the instauration of prevention programs guided to target populations. An effective program of early diagnosis and treatment of osteoporosis is the gold standard method to attend correctly this "silent illness". The roads points of actuation are related with an early detection of the risks factor in each patient before the fracture and others complications takes place. Them, we must recommend healthful habits of life to avoid the appearance of osteoporosis and osteoporosis fracture. The Services of Prevention of Labour Risk have a privileged position to develop this prevention programes.
Simulación en laboratorio mediante ensayos de corrosión acelerada de la presencia y contenido en sales solubles en los productos de corrosión atmosférica del acero
de la Fuente, D.,Chico, B.,Morcillo, M.
Revista de Metalurgia , 2005,
Abstract: In an attempt to approximate what occurs in the atmosphere, this work has established a methodology using accelerated corrosion tests to contaminate steel surfaces with similar levels of chlorides and sulphates to those founded in atmospheric natural exposure. The results show that by selecting the variable of exposure time in the salt fog cabinet, in the case of chlorides, or the volume of SO2 introduced in the KESTERNICH cabinet, in the case of sulphates, it has been possible to contaminate steel substrates with similar preestablished contents of these salts to those obtained naturally after three months of exposure in three atmospheres of different aggressivities: Cabo Vilano (marine); Aviles (industrial); and Madrid (urban). En un intento de aproximación a lo que sucede en la atmósfera, en el presente trabajo, se ha establecido una metodología mediante el empleo de ensayos de corrosión acelerada, para contaminar superficies de acero con niveles de cloruros y sulfates, del orden de los encontrados de forma natural en la atmósfera. Los resultados obtenidos muestran que, eligiendo como variable el tiempo de exposición en la cámara de niebla salina, en el caso de los cloruros, y el volumen de SO2 introducido en la cámara KESTERNICH, en el caso de los sulfatos, ha sido posible contaminar substratos de acero con unos contenidos preestablecidos en dichas sales, similares a los obtenidos de forma natural tras un período de exposición de tres meses en tres atmósferas de distinta agresividad: Cabo Vilano (marina). Avilés (industrial) y Madrid (urbana).
Use of zinc-rich primers co-pigmented with phosphates applied on rusty steel surfaces contaminated with soluble salts
de la Fuente, D.,Chico, B.,Morcillo, M.
Revista de Metalurgia , 2003,
Abstract: Zinc-rich primers (ZRP) offer good anti-corrosive behaviour, and are an ecologically acceptable solution, when applied on carbon steel substrates that are rusted and contaminated with soluble salts (chlorides and sulphates), provided certain critical contamination thresholds are not exceeded. The use of phosphate-type co-pigments in ZRP formulations, could lead to an increase in tolerable critical levels for soluble salts. This work discusses the results of a comparative study carried out with ZRP and non-ZRP systems incorporating various types of co-pigments in several concentrations, applied on substrates contaminated with different chloride and sulphate levels. The study considers the results of atmospheric exposure test (24 months in Madrid atmosphere) and of accelerated humidity condensation tests. Las imprimaciones ricas en zinc (IRZ) ofrecen un buen comportamiento, además de ser una solución ecológicamente aceptable, cuando se aplican sobre substratos de acero al carbono herrumbrado y contaminado con sales solubles (cloruros y sulfatos), siempre que no se superen ciertos umbrales críticos de contaminación. El empleo en la formulación de las IRZ de copigmentos de tipo fosfato podría suponer un aumento en los niveles críticos tolerables de sales solubles. En el presente trabajo se discuten los resultados del estudio comparativo llevado a cabo con sistemas IRZ y no IRZ con diferentes tipos de estos copigmentos en varias proporciones, aplicados sobre substratos contaminados con distintos niveles de cloruros y sulfatos. El estudio incluye los resultados tanto del ensayo de exposición atmosférica (24 meses en la atmósfera de Madrid) como el ensayo acelerado de condensación de humedad.
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