2,300 research outputs found
Almost sharp nonlinear scattering in one-dimensional Born-Infeld equations arising in nonlinear Electrodynamics
We study decay of small solutions of the Born-Infeld equation in 1+1
dimensions, a quasilinear scalar field equation modeling nonlinear
electromagnetism, as well as branes in String theory and minimal surfaces in
Minkowski space-times. From the work of Whitham, it is well-known that there is
no decay because of arbitrary solutions traveling to the speed of light just as
linear wave equation. However, even if there is no global decay in 1+1
dimensions, we are able to show that all globally small ,
solutions do decay to the zero background state in space, inside a
strictly proper subset of the light cone. We prove this result by constructing
a Virial identity related to a momentum law, in the spirit of works
\cite{KMM,KMM1}, as well as a Lyapunov functional that controls the energy.Comment: 12 pages; This is version 2. Some typos corrected and sections
organized differently for ease readin
Working career progress in the tourism industry : temp-to perm transitions in Spain
In this article, we analyze the dynamics of temporary workersâ transitions into permanent contracts for
workers related to the tourism industry. For this purpose, we use an administrative retrospective dataset
from Spanish Social security records. Results show that while individuals with a weaker attachment to the
tourism industry achieve open-ended contracts sooner than in most other industries, on the contrary, it
takes more time to those with a greater attachment to the tourism industry to exit from the temporary
status. In addition, we find that for workers substantially engaged in the tourism industry, it takes more
time to reach an open-ended contract when they have held between six and ten contracts in the past (as
opposed to holding only one previous contract). On the contrary, for individuals with a weaker attachment
to the tourism industry, holding between two and ten previous contracts implies a quicker exit from
temporality
Long-term effects of involuntary job separations on labour careers
In this article, we analyse whether involuntary job separations present long-term effects upon individuals' careers, and the magnitude of such effects. For this purpose, the impact of involuntary job separations on three measures of occupational prestige is examined, using the British Household Panel Survey. Involuntary job separations are found to show a negative effect upon those occupational prestige scales. In particular, when additional involuntary job separations are suffered, this negative impact is persistent and cumulative. Moreover, this observed decrease in prestige levels is enhanced by the length of job separations. Our results help to explain why displaced workers suffer persistent earnings losses compared to non-displaced workers along their work-life history
Career breaks of women due to family reasons: a long-term perspective using retrospective data
In this article, we analyse whether family-related quits present long-term effects upon women's careers, and the magnitude of such effects. For this purpose, the impact of family-related breaks in the first ten years of their labour careers on three measures of occupational prestige is examined, using the British Household Panel Survey. Women who are intermittently attached to the labour market are found to work, on average, in occupations associated to significantly lower prestige levels. In particular, additional family-related interruptions have a negative impact that becomes persistent and cumulative. Moreover, the observed decrease in prestige levels is enhanced by the length of job separations
Breaks in women's careers due to family reasons: a long-term perspective
We analyse whether family-related quits present long-term effects upon women s careers, which are summarized in three measures of occupational prestige. There is an association between intermittent attachment to the labour market and being engaged in occupations with lower prestige levels. In causal terms, we find that women choose jobs with lower occupational prestige anticipating future family-related quits. The database consists of the retrospective information of the British Household Panel Surve
Job matching quality effects of employment promotion measures for people with disabilities
In this article, we evaluate the influence that employment promotion measures designed for disabled people have on the latter's job matching quality through the use of matching analysis. We focus on two aspects of quality: the type of contract held (either permanent or temporary) and whether or not the individual is searching for another job. We find that employment promotion measures do not improve the match's job quality. Furthermore, the use of specialized labour market intermediation services by disabled individuals does not affect their job matching quality. As an additional contribution, our definition of disability eludes the self-justification bias
Study of the disordered one-dimensional contact process
New theoretical and numerical analysis of the one-dimensional contact process
with quenched disorder are presented.
We derive new scaling relations, different from their counterparts in the
pure model, which are valid not only at the critical point but also away from
it due to the presence of generic scale invariance. All the proposed scaling
laws are verified in numerical simulations. In addition we map the disordered
contact process into a Non-Markovian contact process by using the so called Run
Time Statistic, and write down the associated field theory. This turns out to
be in the same universality class as one derived by Janssen for the quenched
system with a Gaussian distribution of impurities.
Our findings here support the lack of universality suggested by the field
theoretical analysis: generic power-law behaviors are obtained, evidence is
shown of the absence of a characteristic time away from the critical point, and
the absence of universality is put forward. The intermediate sublinear regime
predicted by Bramsom et al. is also found.Comment: 18 Figures (fig. 1 and 9 not available), Late
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