6,375 research outputs found
Productivity growth and technological change in Europe and the U.S.
This paper presents an evaluation on the technological sources of labor productivity growth across European countries and the US economy for the period 1980-2004. Assets of capital are divided into those related to the information and communication technologies (ICT), and non-ICT assets. Technological progress is divided into neutral change and investment specific change. Previous exercises have aimed at ICT as a serious contributor to the upsurge of US productivity from 1995 on. Contribution to productivity growth from each type of technological progress for the US and EU-15 countries is computed using two different approaches: a growth accounting and a general equilibrium. The US and Denmark are the countries with the larger contribution from ICT-technological progress. Overall, we find that Europe is well behind the US in terms of the effects of ICT technological change.Productivity growth, Investment-specific technological change, Neutral technological change
Deep into the Water Fountains: The case of IRAS 18043-2116
(Abridged) The formation of large-scale (hundreds to few thousands of AU)
bipolar structures in the circumstellar envelopes (CSEs) of post-Asymptotic
Giant Branch (post-AGB) stars is poorly understood. The shape of these
structures, traced by emission from fast molecular outflows, suggests that the
dynamics at the innermost regions of these CSEs does not depend only on the
energy of the radiation field of the central star. Deep into the Water
Fountains is an observational project based on the results of programs carried
out with three telescope facilities: The Karl G. Jansky Very Large Array
(JVLA), The Australia Telescope Compact Array (ATCA), and the Very Large
Telescope (SINFONI-VLT). Here we report the results of the observations towards
the WF nebula IRAS 180432116: Detection of radio continuum emission in the
frequency range 1.5GHz - 8.0GHz; HO maser spectral features and radio
continuum emission detected at 22GHz, and H ro-vibrational emission lines
detected at the near infrared. The high-velocity HO maser spectral
features, and the shock-excited H emission detected could be produced in
molecular layers which are swept up as a consequence of the propagation of a
jet-driven wind. Using the derived H column density, we estimated a
molecular mass-loss rate of the order of Myr. On the
other hand, if the radio continuum flux detected is generated as a consequence
of the propagation of a thermal radio jet, the mass-loss rate associated to the
outflowing ionized material is of the order of 10Myr.
The presence of a rotating disk could be a plausible explanation for the
mass-loss rates estimated.Comment: 10 pages, 5 figures. Accepted for publication in A&
La función ejecutiva de actualización y el rendimiento en comprensión lectora y resolución de problemas
In this investigation, the capacity of the working memory (WM) updating executive function to predict individual differences in reading comprehension and problem solving was analyzed in 5th-graders of Primary Education. In addition, we examined whether this relation is direct or mediated by domain-general or domain-specific variables. For this purpose, a series of tasks was administered to assess fluid intelligence, WM information updating, arithmetic abilities, arithmetic problem solving, lexical processing, and reading comprehension in 49 students aged between 10 and 11 years. The results support the idea that updating is an important predictor of reading comprehension, beyond the influence of domainspecific skills and fluid intelligence. In the case of problem solving, our findings confirm that updating plays an important role although, perhaps due to task content, the relation seems to be mediated by fluid intelligence at this developmental stageEsta investigación analizó, en niños de 5º curso de Educación Primaria, la capacidad predictora de la función ejecutiva de actualización de la Memoria Operativa (MO) en las diferencias individuales en comprensión lectora y resolución de problemas aritméticos. Además, se estudió si esta relación es directa o está mediada por variables de dominio general o específico. Con este fin se administró un conjunto de pruebas que evalúan la inteligencia fluida, la actualización de la información en la MO, la competencia aritmética, la resolución de problemas aritméticos, el procesamiento léxico y la comprensión lectora a 49 alumnos con edades comprendidas entre los 10 y 11 años. Los resultados apoyan la idea que la actualización de la MO es un
importante predictor de la comprensión lectora, más allá de la influencia de las habilidades de dominio específico y de la inteligencia fluida. En el caso de la resolución de problemas, nuestros hallazgos confirman que la actualización juega un papel importante aunque, en este momento evolutivo, quizá por el propio contenido de la tarea, la relación parece mediada por la inteligencia fluid
Una experiencia sobre la elaboración de material didáctico informático para complementar una asignatura de laboratorio en la Licenciatura en Química
En este artículo se expone y se analiza el trabajo realizado en el Departamento de Química Física y Analítica de la Universidad de Oviedo para incorporar las nuevas tecnologías de la comunicación a la docencia de la asignatura “Introducción a la Experimentación en Química Física”. La metodología con la que se elaboró este proyecto se basa en tres aspectos: exposición de contenidos, actividad del alumno y corrección de dicha actividad. Para valorar la utilización del complemento virtual por los alumnos y su opinión se diseñó una encuesta.This article presents and analyzes the work done in the Department of Physical Chemistry and Analytical of the University of Oviedo to incorporate the new communication technologies to the teaching of the subject "Introduction to experimentation in Physical Chemistry". The methodology that was developed this project is based on three aspects: exhibition of content, activity of the pupil and correction of such activity. To evaluate the use of virtual complement by the pupils and their opinion was designed a survey
Glassy dynamics, aging and thermally activated avalanches in interface pinning at finite temperatures
We study numerically the out-of-equilibrium dynamics of interfaces at finite
temperatures when driven well below the zero-temperature depinning threshold.
We go further than previous analysis by including the most relevant
non-equilibrium correction to the elastic Hamiltonian. We find that the
relaxation dynamics towards the steady-state shows glassy behavior, aging and
violation of the fluctuation-dissipation theorem. The interface roughness
exponent alpha approx 0.7 is found to be robust to temperature changes. We also
study the instantaneous velocity signal in the low temperature regime and find
long-range temporal correlations. We argue 1/f-noise arises from the merging of
local thermally-activated avalanches of depinning events.Comment: 4 pages, 4 figure
Recommended from our members
Phase 1 repolarization rate defines Ca2+ dynamics and contractility on intact mouse hearts.
In the heart, Ca2+ influx through L-type Ca2+ channels triggers Ca2+ release from the sarcoplasmic reticulum. In most mammals, this influx occurs during the ventricular action potential (AP) plateau phase 2. However, in murine models, the influx through L-type Ca2+ channels happens in early repolarizing phase 1. The aim of this work is to assess if changes in the open probability of 4-aminopyridine (4-AP)-sensitive Kv channels defining the outward K+ current during phase 1 can modulate Ca2+ currents, Ca2+ transients, and systolic pressure during the cardiac cycle in intact perfused beating hearts. Pulsed local-field fluorescence microscopy and loose-patch photolysis were used to test the hypothesis that a decrease in a transient K+ current (Ito) will enhance Ca2+ influx and promote a larger Ca2+ transient. Simultaneous recordings of Ca2+ transients and APs by pulsed local-field fluorescence microscopy and loose-patch photolysis showed that a reduction in the phase 1 repolarization rate increases the amplitude of Ca2+ transients due to an increase in Ca2+ influx through L-type Ca2+ channels. Moreover, 4-AP induced an increase in the time required for AP to reach 30% repolarization, and the amplitude of Ca2+ transients was larger in epicardium than endocardium. On the other hand, the activation of Ito with NS5806 resulted in a reduction of Ca2+ current amplitude that led to a reduction of the amplitude of Ca2+ transients. Finally, the 4-AP effect on AP phase 1 was significantly smaller when the L-type Ca2+ current was partially blocked with nifedipine, indicating that the phase 1 rate of repolarization is defined by the competition between an outward K+ current and an inward Ca2+ current
Laboratory and telescope demonstration of the TP3-WFS for the adaptive optics segment of AOLI
AOLI (Adaptive Optics Lucky Imager) is a state-of-art instrument that combines adaptive optics (AO) and lucky imaging (LI) with the objective of obtaining diffraction limited images in visible wavelength at mid- and big-size ground-based telescopes. The key innovation of AOLI is the development and use of the new TP3-WFS (Two Pupil Plane PositionsWavefront Sensor). The TP3-WFS, working in visible band, represents an advance over classical wavefront sensors such as the Shack-Hartmann WFS (SH-WFS) because it can theoretically use fainter natural reference stars, which would ultimately provide better sky coverages to AO instruments using this newer sensor. This paper describes the software, algorithms and procedures that enabled AOLI to become the first astronomical instrument performing real-time adaptive optics corrections
in a telescope with this new type of WFS, including the first control-related
results at the William Herschel Telescope (WHT)This work was supported by the Spanish Ministry of Economy under the projects AYA2011-29024, ESP2014-56869-C2-2-P, ESP2015-69020-C2-2-R and DPI2015-66458-C2-2-R, by project 15345/PI/10 from the Fundación Séneca, by the Spanish Ministry of Education under the grant FPU12/05573, by project ST/K002368/1 from the Science and Technology Facilities Council and by ERDF funds from the European Commission. The results presented in this paper are based on observations made with the William Herschel Telescope operated on the island of La Palma by the Isaac Newton Group in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias. Special thanks go to Lara Monteagudo and Marcos Pellejero for their timely contributions
Children’s improvement of a motor response during backward falls through the implementation of a safe fall program
The World Health Organization has warned that, in children, the second cause of death from unintentional injuries are falls. The objective of this study was to analyze the motor response of primary schoolchildren when a backwards fall occurs. These analyses occurred before and after interventions of the Safe Fall program, which aims to teach safe and protected ways of backward falling. A quasi-experimental research design was used, with a sample of 122 Spanish (Sevillian) schoolchildren in the 10–12 age bracket. The INFOSECA ad-hoc observation scale was used for data
collection: this scale registers 5 essential physical reactions throughout the process of a safe and protected backwards fall. After that, a number of descriptive, correlational and contrast statistics were applied. The value used in the McNemar test to establish statistical significance was p < 0.05. Results
showed that over 85% of students had developed the competence to correctly perform all five physical motions that allow for a safer backward fall. The teaching of safe and protected techniques for falling backwards in child population in Primary Education is possible through the implementation of the
Safe Fall program in Physical Education classes, which can help making falls safer, diminishing the risk and severity of the injuries they cause
Relaciones históricas entre olmos y vides
In Spanish, the expression «You cannot ask an elm for pears» denotes something that is impossible. Although its origin is unknown, it can be dated back to the 1st century BC, when appeared the Latin maxim Pirum, non ulmum accedas, si cupias pira (You should go to a pear-tree for pears, not to an elm), a sentence from which we believe the Spanish saying comes. The objective of this paper is to show how the historical relationship of elms and vines can be related to these expressions, because elms did not give pears but, figuratively, did give grapes. The cultivation of vines was soon included among the domestic plants at the beginning of the Neolithic Age. During the Assyrian Empire (7th century BC), vines are represented growing up around pine-like trees. The first documentary evidence of the marriage between elms and vines is found in the Ancient Greece: a wine called Pteleaikós oinos is mentioned, which refers to the region where it was produced, Ptelea (Elm). During the Roman Ages, the cultivation of vines married to elms became more important as it is reflected in the treatises in agriculture. This technique was so common that it appears recurrently as a topic in Poetry and Drama. The classical books were copied during the Middle Ages, and only the Arabian agronomists in the Iberian Peninsula gave new evidence of the relationship between vines and elms in the 12th century. Some four hundred years later the use of elms as props for vines was rare in Spain and, although not to elms, the marriage of vines to trees lasted in the South of Spain until the 19th century. In Italy, elms and vines were even planted together in the 20th century, before the Dutch Elm Disease began to kill the plantations of trees and farmers were forced to replace them with poles.En castellano, la expresión «No se le puede pedir peras al olmo» indica algo imposible. A pesar de que su origen es desconocido, puede situarse en el siglo I A.C., cuando aparece la máxima latina Pirum, non ulmum accedas, si cupias pira (Al peral acude, no al olmo, si quieres peras), de la cual creemos que procede la expresión española. En este trabajo se pretende mostrar que la relación histórica de los olmos y las vides puede estar relacionada con estas expresiones en la medida en que los olmos no daban peras mas, en sentido figurado, daban uvas. La vid fue una de las primeras plantas cultivadas ya desde el comienzo del Neolítico. En el Imperio Asirio (s. VII A.C.), las vides aparecen representadas creciendo alrededor de árboles que se asemejan a pinos. La primera evidencia documental del maridaje de olmos y vides la encontramos en la Grecia Clásica, donde se menciona un vino llamado Pteleaikós oinos que hace referencia a la región dónde se producía, Ptelea (Olmo). Durante la época Romana el cultivo de las vides maridadas a los olmos adquiere mayor importancia, como se refleja en los tratados de agricultura. La práctica fue tan común que aparece de modo recurrente como tópico en la literatura. Los textos clásicos son copiados durante la Edad Media, y sólo los agrónomos árabes de la península Ibérica proporcionan nuevas evidencias de la relación entre vides y olmos ya en el siglo XII. Cuatro siglos después la utilización de olmos como tutores de las vides era rara en España, pero el maridaje de las vides con árboles, aunque no olmos, duró en el Sur de España hasta el siglo XIX. Sin embargo en Italia olmos y vides se plantaban juntos incluso en el siglo XX, antes de que la grafiosis comenzara a matar las plantaciones de árboles y los agricultores se vieran obligados a sustituirlos por postes
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