3,377 research outputs found
Labor Demand and Information Technologies: Evidence for Spain, 1980-2005
Using the EU KLEMS dataset we test the capital-skill complementarity hypothesis in a cross-section of sectors in Spain between 1980 and 2005. We analyze three groups of workers, who are classed according to skill level: high, medium and low. Capital assets have been broken down into ICT (information and communication technologies) assets and non-ICT assets. Acquisition and usage costs of ICT assets declined throughout the period studied, both in absolute terms and relative to the other capital assets and workers. Our principal finding is that the substitutibility between workers and ICT assets falls as worker skill level rises. In fact, the ICT assets were strongly complement with highly skilled workers and were not substitutive with them. Throughout the period analyzed, the fraction of employed medium- and high-skill workers rose by 21% and 12%, respectively, to the disadvantage of low-skill workers. After decomposing these changes, we found that the latter were dominated by an ajustment within sectors more than by a composition effect or adjustment between sectors. These adjustments may be explained by reference to the estimated elasticities of substitution.capital-skill complementarity, ICT, translog cost function, elasticity of substitution.
Community acquired bacterial meningitis in Cuba: a follow up of a decade
BACKGROUND: Community acquired Bacterial Meningitis (BM) remains a serious threat to global health. Cuban surveillance system for BM allowed to characterize the main epidemiological features of this group of diseases, as well as to assess the association of some variables with mortality. Results of the BM surveillance in Cuba are presented in this paper. METHODS: A follow up of BM cases reported to the Institute "Pedro Kourí" by the National Bacterial Meningitis Surveillance System from 1998 to 2007 was completed. Incidence and case-fatality rate (CFR) were calculated. Univariate analysis and logistic regression were used to elucidate associated factors to mortality comparing death versus survival. Relative Risk (RR) or odds ratio and its 95% confidence interval (CI 95%) were estimated, using either a Chi-squared Test or Fisher's Exact Test as appropriate. A Holt-Winters model was used to assess seasonality. RESULTS: 4 798 cases of BM (4.3 per 100 000 population) were reported, with a decreasing trend of the incidence. Highest incidence was observed in infants and elderly. Overall CFR reached 24.1% affecting mostly older adults. S. pneumoniae (23.6%), N. meningitidis(8.2%) and H. influenzaetype b (6.0%) were the main causative agents. Males predominate in the incidence. Highest incidence and CFR were mainly clustered in the centre of the island. The univariate analysis did not show association between delayed medical consultation (RR = 1.20; CI = 1.07-1.35) or delayed hospitalization (RR = 0.98; CI = 0.87-1.11) and the fatal outcome. Logistic regression model showed association of categories housewife, pensioned, imprisoned, unemployed, S. peumoniae and other bacteria with mortality. Seasonality during September, January and March was observed. CONCLUSIONS: The results of the National Program for Control and Prevention of the Neurological Infectious Syndrome evidenced a reduction of the BM incidence, but not the CFR. Multivariate analysis identified an association of mortality with some societal groups as well as with S. peumoniae
Raman microprobe characterization of electrodeposited S-rich CuIn(S,Se)2 for photovoltaic applications: Microstructural analysis
This article reports a detailed Raman scattering and microstructural characterization of S-rich CuIn(S,Se)2 absorbers produced by electrodeposition of nanocrystalline CuInSe2 precursors and subsequent reactive annealing under sulfurizing conditions. Surface and in-depth resolved Raman microprobe measurements have been correlated with the analysis of the layers by optical and scanning electron microscopy, x-ray diffraction, and in-depth Auger electron spectroscopy. This has allowed corroboration of the high crystalline quality of the sulfurized layers. The sulfurizing conditions used also lead to the formation of a relatively thick MoS2 intermediate layer between the absorber and the Mo back contact. The analysis of the absorbers has also allowed identification of the presence of In-rich secondary phases, which are likely related to the coexistence in the electrodeposited precursors of ordered vacancy compound domains with the main chalcopyrite phase, in spite of the Cu-rich conditions used in the growth. This points out the higher complexity of the electrodeposition and sulfurization processes in relation to those based in vacuum deposition techniques
Analysis of the coating integrityduring a coronary stent deployment
Las afecciones cardiovasculares constituyen en la actualidad una causa frecuente de muerte. Una de estas afecciones es la ateroesclerosis, la cual provoca la reducción de la luz arterial. En aras de solucionar tal afección se han desarrollado varios tratamientos, ganando terreno la Angioplastia Coronaria Transluminar Percutánea (PTCA) con colocación de estent. En la actualidad muchos de estos dispositivos son recubiertos para aumentar la biocompatibilidad y disminuir los riesgos de reestenosis. Dado la posibilidad de fallas o roturas de los recubrimientos y los riesgos asociados a estas, es de gran importancia el estudio del comportamiento de la unión estentrecubrimiento durante la fase de expansión del estent. En esta investigación se estudia la posible ocurrencia de delaminación del recubrimiento durante la expansión de un estent y la influencia de parámetros como el espesor y el material del mismo. El estudio parte de la obtención de un modelo geométrico de una celda del estent Sirius Carbostent para su posterior procesamiento por el Método de Elementos Finitos. La simulación por tal método, se desarrolló, aplicando restricciones al movimiento de forma tal que la celda modelada simule su comportamiento durante la expansión de un estent.
Considerando estos aspectos fue posible evaluar la integridad
del recubrimiento. Con los modelos desarrollados se logró
predecir la ocurrencia de delaminación durante la expansión del
estent y se determinó que al aumentar el espesor del
recubrimiento aumenta el riesgo de ocurrencia de la misma. Se
obtuvo además una ecuación general que permite determinar
el esfuerzo máximo de contacto para celdas en forma de U.The cardiovascular diseases constitute one of the main causes of death worldwide. One of the main diseases is atherosclerosis, which causes narrowing of the arterial lumen. In order to solve this condition, several treatments have been developed, and Percutaneous Transluminal Coronary Angioplasty (PTCA) with the placement of stent have gained
relevancy. Many of these devices are currently coated to increase the biocompatibility and to decrease the restenosis risks. The biomechanical studies of the stent-coating interface behavior are necessary given the associated risks to possibility of failures or breakages of the coating during stent deployment. In this study the possible occurrence of coating delamination during stent deployment and the influence of parameters as the thickness and material were studied. The study starts by obtaining a geometric model of a stent unit of the Sirius Carbostent stent for the further processing by the Finite Element Method. The simulation was developed by applying restrictions so that the modeled stent hinge simulates his behavior during stent deployment. Considering these aspects it was possible to evaluation the coating integrity. With this model it was possible to predict the occurrence of delamination during stent deployment and to determine that the delamination risks increases with increasing the coating thickness. Finally, it was obtained a general function that allows to determine the maximal contact stress for a stent hinge with an U shape.Peer Reviewe
Módulo online de cinemática como soporte a la enseñanza semipresencial de la Física en Ingeniería
Las nuevas tecnologías en materia de información y comunicación nos ofrecen las oportunidades para un mayor aprovechamiento de las herramientas y recursos, que permita mejorar el proceso de enseñanza-aprendizaje. Aprovechando las nuevas oportunidades que ofrecen medios como internet se diseñó y desarrolló un sistema hipermedial (website) denominado: programa SEHCP (Software Educativo Hipermedia Cinemática de la Partícula) como soporte al proceso de enseñanza-aprendizaje del tema Cinemática de la Partícula. El software fue utilizado por una muestra representativa de los tipos de destinatarios para los que fue diseñado y la consiguiente evaluación diagnóstica; la muestra estuvo conformada por alumnos de la asignatura Física Mecánica y alumnos del Curso Introductorio de la Facultad de Ingeniería de la Universidad de Carabobo-Venezuela
JCLAL: A Java framework for active learning
Active Learning has become an important area of research owing to the increasing number of real-world problems which contain labelled and unlabelled examples at the same time. JCLAL is a Java Class Library for Active Learning which has an architecture that follows strong principles of object-oriented design. It is easy to use, and it allows the developers to adapt, modify and extend the framework according to their needs. The library offers a variety of active learning methods that have been proposed in the literature. The software is available under the GPL license
KMOS LENsing Survey (KLENS) : morpho-kinematic analysis of star-forming galaxies at
We present results from the KMOS lensing survey-KLENS which is exploiting
gravitational lensing to study the kinematics of 24 star forming galaxies at
with a median mass of and median
star formation rate (SFR) of . We find that 25% of
these low-mass/low-SFR galaxies are rotation dominated, while the majority of
our sample shows no velocity gradient. When combining our data with other
surveys, we find that the fraction of rotation dominated galaxies increases
with the stellar mass, and decreases for galaxies with a positive offset from
the main sequence. We also investigate the evolution of the intrinsic velocity
dispersion, , as a function of the redshift, , and stellar mass,
, assuming galaxies in quasi-equilibrium (Toomre Q parameter equal
to 1). From the relation, we find that the redshift evolution of
the velocity dispersion is mostly expected for massive galaxies (). We derive a relation, using
the Tully-Fisher relation, which highlights that a different evolution of the
velocity dispersion is expected depending on the stellar mass, with lower
velocity dispersions for lower masses, and an increase for higher masses,
stronger at higher redshift. The observed velocity dispersions from this work
and from comparison samples spanning appear to follow this relation,
except at higher redshift (), where we observe higher velocity dispersions
for low masses () and lower velocity
dispersions for high masses () than
expected. This discrepancy could, for instance, suggest that galaxies at
high- do not satisfy the stability criterion, or that the adopted
parametrisation of the specific star formation rate and molecular properties
fail at high redshift.Comment: Accepted for publication in A&A, 21 pages, 10 figure
Economic shocks and their efect on the schooling and labor participation of youth: evidence from the metal mining price boom in Chilean counties
We analyze the efect of an exogenous economic shock on youth, specifcally their incentive for preferring to participate in the labor market over continuing their education. We examine the Chilean case and the sustained increase in the market price of the minerals extracted there during the period of Metal Mining Price Boom between the years 2003 and 2011. Chile is a large-scale producer of metals, being the world’s largest producer of copper and the third largest producer of molybdenum. The prices of such metals increased steadily during the shock, what boosted the economic growth and the demand for labor. This shock altered the skill composition in the labor market, increasing the jobs for low- and medium–low-skilled
workers in the counties more exposed to the shock, thus being the metal mining counties the most afected by its impact. According to this, our results show a negative impact of the shock on returns to schooling that simultaneously reduced school enrollment rates while increasing youth labor participation in those countie
Las industrias de salazones del litoral onubense : los casos de "El Eucaliptal" (Punta Umbría), y "El Cerro del Trigo" (Doñana, Almonte)
Una de las actividades que mejor definen la economía de época romana en el Golfo de Cádiz es la industria relacionada con la producción y comercialización de salsas de pescado (salazones). Según los testimonios arqueológicos, los orígenes de esta producción se remontan a momentos prerromanos en ámbitos geográficos relacionados con el comercio gaditano. Dado el escaso número de este tipo de instalaciones conocidas en la costa onubense durante el período romano, donde hasta la fecha sólo existían escasas referencias bibliográficas, se presentan en este trabajo los nuevos yacimientos dedicados a la producción de salazones descubiertos en prospecciones y excavaciones por el Área de Arqueología de la Universidad de Huelva, y se hace hincapié en una mayor abundancia de este tipo de instalaciones, que fenómenos geomorfológicos recientes, principalmente los donares, impiden valorar en su verdadera dispersión._____________________________One of the activities which better define the economy of Roman period in the Gulf of
Cadiz is the industry related to the production and marketing sauce of fish (fish-salting).
According to the archaeological testimonies, the origins of this production go back to preroman
moments, in areas related to the Cadiz trade.
In view of the scanty number of this type of facilities know in Huelva coast during
the Roman period, where up to the date only scanty bibliographical references existed,
there appear in this work the new deposits dedicated to the production of saltings discovered in explorations and excavations for the Area of Archaeology of the University of Huelva.
And it is emphisized a bigger abundance of this type of factories, which geomorphological
phenomenon, principally the littoral dunes system, prevent valuing at its real dispersion
- …