18,145 research outputs found
Regional Intergration and Migration: An Economic Geography Model with Hetergenous Labour Force
This paper aims to analyse the effect of deepening regional integration on the incentive for factors of production, in particular labour, to spatially relocate. We adopt a general equilibrium, economic-geography model built on Krugman (1991) allowing for skill heterogeneity in the manufacturing sector. At a given level of trade costs, due to the productivity premium associated with the concentration of high-skilled workers in one region, this type of worker will be more willing to migrate than low-skilled ones. The paper shows the existence of a range of trade costs for which only high-skilled workers have an incentive to migrate. Therefore, introducing labour heterogeneity in the basic core-periphery model enables us to explain one of the most striking features of interregional migration patterns: the positive self-selection of the migrants.
Transport properties of a meson gas
We present recent results on a systematic method to calculate transport
coefficients for a meson gas (in particular, we analyze a pion gas) at low
temperatures in the context of Chiral Perturbation Theory. Our method is based
on the study of Feynman diagrams with a power counting which takes into account
collisions in the plasma by means of a non-zero particle width. In this way, we
obtain results compatible with analysis of Kinetic Theory with just the leading
order diagram. We show the behavior with temperature of electrical and thermal
conductivities and shear and bulk viscosities, and we discuss the fundamental
role played by unitarity. We obtain that bulk viscosity is negligible against
shear viscosity near the chiral phase transition. Relations between the
different transport coefficients and bounds on them based on different
theoretical approximations are also discussed. We also comment on some
applications to heavy-ion collisions.Comment: 4 pages, 4 figures, IJMPE style. Contribution to the International
Workshop X Hadron Physics (2007), Florianopolis, Brazil. Accepted for
publication in IJMPE; 1 typo correcte
Electromagnetic fields and transport coefficients in a hot pion gas
We present recent results on finite temperature electromagnetic form factors
and the electrical conductivity in a pion gas. The standard Chiral Perturbation
Theory power counting needs to be modified for transport coefficients. We pay
special attention to unitarity and to possible applications for dilepton and
photon production.Comment: 4pp, 2 figures, talk given at "Strong and Electroweak Matter 2006",
BNL, May 200
The relation between naming and literacy in children with word-finding difficulties
Difficulties with picture naming tasks are associated with literacy problems. Children with dyslexia, when given naming tasks, are slower to produce words and have a higher proportion of errors (Wolf and Bowers, 1999). However, little is known about the relation between literacy and naming in other populations. This study investigates this relation in 20 children (aged 6:6 – 7:11) with word-finding difficulties (WFDs). The children in our sample performed very poorly on assessments of naming, but unlike children with dyslexia, were found to have decoding and spelling abilities within the normal range. In addition, their abilities on phonological awareness tasks were at a similar level to their decoding abilities. In contrast, performance on reading comprehension and language comprehension was significantly worse than for decoding, spelling and rhyme awareness. The implications of our findings for models concerned with understanding the relation between naming speed and literacy abilities are discussed
Transport coefficients of a massive pion gas
We review or main results concerning the transport coefficients of a light
meson gas, in particular we focus on the case of a massive pion gas. Leading
order results according to the chiral power-counting are presented for the DC
electrical conductivity, thermal conductivity, shear viscosity, and bulk
viscosity. We also comment on the possible correlation between the bulk
viscosity and the trace anomaly in QCD, as well as the relation between
unitarity and a minimum of the quotient near the phase transition.Comment: Talk given at the 5th International Conference on Quarks and Nuclear
Physics (QNP09), Beijing, September 21-26, 200
Chiral symmetry and mesons in hot and dense matter: recent developments
We review recent results on properties of the meson gas relevant for Heavy
Ion Collision and Nuclear Matter experiments, within the framework of chiral
lagrangians. In particular, we describe the temperature and density evolution
of the and poles and its connection with chiral symmetry
restoration, as well as the chemical nonequilibrated phase and transport
coefficients.Comment: Proceedings of the "Chiral10 International Workshop on Chiral
Symmetry in Hadrons and Nuclei", Valencia, Spain, 21-24 june 2010. 9 pages, 5
figures. AIP Proceedings styl
I’m Doing Better on My Own: Social Inhibition in Vocabulary Learning in Adults
Published: 05 June 2019Vocabulary learning is better achieved by children facing a teacher than when presented to the same teacher through video (so-called “video deficit” effect), which has significant implications for toddlers’ education. Since millions of adults also learn new vocabulary when acquiring a second language (L2), it is important to explore whether adults suffer from “video deficit” effects, as children do. In the present study, we report two experiments in which Spanish native late learners of English were involved in a vocabulary learning task. In Experiment 1, participants had to learn English (L2) labels associated to real objects. In Experiment 2, participants had to learn English (L2) and Spanish (L1) labels associated to novel objects. In both experiments, vocabulary learning was divided into three conditions: In the NoFace condition, participants were presented with the objects and their auditory labels, through video. In the Video condition, a teacher was showing the objects and uttering their names, through video. The Live condition was equivalent, except that the teacher was facing the participants in the room. Each condition was followed by a recall test. Better learning in Video compared to NoFace condition revealed that adults benefit from the teacher’s display with direct gaze, confirming the fundamental role of face display with direct gaze in social communication in adults. Interestingly, adults learned better through Video than in the Live condition. Those results were obtained in L2 vocabulary learning in both Experiments 1 and 2, and also generalized to native language in Experiment 2. We argue that adults suffer from social inhibition, meaning that they perform worse when in the presence of another person during task performance. In sum, we show that video-mediated teaching might not be detrimental for adults learning new vocabulary lists, as it is the case for young children. These results might have important implications for pedagogical programs targeting adults’ second language vocabulary learning, since proper acquisition of vocabulary list can be achieved through video including a teacher’s display.This research was funded by a grant from the FP7/2007–2013 Cooperation grant agreement 613465-AThEME, an ERC grant from the European Research Council (ERC-2011-ADG-295362), grants from the Spanish Government (PSI2014-54500, PSI2015-65694, and PSI2017-82941-P), and from the Basque Government (PI_2015_1_25 and PIBA18_29)
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