17,511 research outputs found

    Sinusoidal electromagnon in RMnO3: Indication of anomalous magnetoelectric coupling

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    The optical spectra in the family of multiferroic manganites RMnO3 is a great puzzle. Current models can not explain the fact that two strong electromagnons are present in the non-collinear spin cycloidal phase, with only one electromagnon surviving the transition into the collinear spin sinusoidal phase. We show that this is a signature of the presence of anomalous magnetoelectric coupling that breaks rotational invariance in spin space and generates oscillatory polarization in the ground state.Comment: 5 pages, 2 figure

    Evolution of domain wall networks: the PRS algorithm

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    The Press-Ryden-Spergel (PRS) algorithm is a modification to the field theory equations of motion, parametrized by two parameters (α\alpha and β\beta), implemented in numerical simulations of cosmological domain wall networks, in order to ensure a fixed comoving resolution. In this paper we explicitly demonstrate that the PRS algorithm provides the correct domain wall dynamics in N+1N+1-dimensional Friedmann-Robertson-Walker (FRW) universes if α+β/2=N\alpha+\beta/2=N, fully validating its use in numerical studies of cosmic domain evolution. We further show that this result is valid for generic thin featureless domain walls, independently of the Lagrangian of the model.Comment: 4 page

    The Effect of Pension Generosity on Early Retirement: A Microdata Analysis for Europe from 1967 to 2004

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    Using pseudo-panel microdata we show that pension generosity affects early retirement decisions. The changes in the average replacement rate and decreases in wealth accrual between 1967 and 2004 have caused an increase in early retirement probabilities from 16% to 63%.Early Retirement; Pension Systems; Pension Neutrality; Pension Generosity; SHARE

    Does Job Satisfaction Improve the Health of Workers?: New Evidence Using Panel Data and Objective Measures of Health

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    This paper evaluates the relationship between job satisfaction and measures of health of workers using the German Socio-Economic Panel (GSOEP). Methodologically, it addresses two important design problems encountered frequently in the literature: (a) cross-sectional causality problems and (b) absence of objective measures of physical health that complement self-reported measures of health status. Not only does using the panel structure with individual fixed effects mitigate the bias from omitting unobservable personal psycho-social characteristics, but employing more objective health measures such as health-system contacts and disability addresses such measurement problems relating to self-report assessments of health status. We find a positive link between job satisfaction (and changes over time therein) and subjective health measures (and changes therein); that is, employees with higher or improved job satisfaction levels feel healthier and are more satisfied with their health. This observation also holds true for more objective measures of health. Particularly, improvements in job satisfaction over time appear to prevent workers from (further) health deterioration.Job satisfaction, well-being, health, panel data analysis

    Evaluation of analytical methodologies to derive vulnerability functions

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    The recognition of fragility functions as a fundamental tool in seismic risk assessment has led to the development of more and more complex and elaborate procedures for their computation. Although vulnerability functions have been traditionally produced using observed damage and loss data, more recent studies propose the employment of analytical methodologies as a way to overcome the frequent lack of post-earthquake data. The variation of the structural modelling approaches on the estimation of building capacity has been the target of many studies in the past, however, its influence in the resulting vulnerability model, impact in loss estimations or propagation of the uncertainty to the seismic risk calculations has so far been the object of restricted scrutiny. Hence, in this paper, an extensive study of static and dynamic procedures for estimating the nonlinear response of buildings has been carried out in order to evaluate the impact of the chosen methodology on the resulting vulnerability and risk outputs. Moreover, the computational effort and numerical stability provided by each approach were evaluated and conclusions were obtained regarding which one offers the optimal balance between accuracy and complexity
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