35,978 research outputs found
Intra-industry trade and labour market adjustment: A reassessment using data on individual workers
We re-examine the relationship between intra-industry trade and labour reallocation, using individual-level data on manufacturing worker moves in the United Kingdom. The contribution of this analysis is twofold. First, we estimate the impact of intra-industry trade on worker moves between occupations as well as between industries. Second, we run individual-level regressions that allow us to control for worker heterogeneity. Our results suggest that intra-industry trade does have the stipulated attenuating effect on worker moves, both between occupations and between industries, but that this effect is relatively small compared to other determinants of labour reallocation
Second order splitting of a class of fourth order PDEs with point constraints
We formulate a well-posedness and approximation theory for a class of generalised saddle point problems with a specific form of constraints. In this way we develop an approach to a class of fourth order elliptic partial differential equations with point constraints using the idea of splitting into coupled second order equations. An approach is formulated using a penalty method to impose the constraints. Our main motivation is to treat certain fourth order equations involving the biharmonic operator and point Dirichlet constraints for example arising in the modelling of biomembranes on curved and flat surfaces but the approach may be applied more generally. The theory for well-posedness and approximation is presented in an abstract setting. Several examples are described together with some numerical experiments
Virtual audio reproduced in a headrest
When virtual audio reproduction is simultaneously required in many seats, such as in aircraft or
cinemas, it may be convenient to use loudspeakers mounted inside each seat's headrest. In
this preliminary study, the feasibility of virtual audio reproduction in the headrest of a single seat
is explored using an inversion technique to compensate for crosstalk and the synthesis of head
related transfer functions. Although large changes in the magnitude of the signals reproduced
at the listener's ears are observed as the listener moves their head within the headrest, informal
listening tests indicate that the reproduced acoustic images are surprisingly stable in about an
eighth of an arc either side of the loudspeaker positions. Not surprisingly, frontal images are
more difficult to reproduce with headrest loudspeakers
Use of mathematical derivatives (time-domain differentiation) on chromatographic data to enhance the detection and quantification of an unknown 'rider' peak
Two samples of an anticancer prodrug, AQ4N, were submitted for HPLC assay and showed an unidentified impurity that eluted as a 'rider' on the tail of the main peak. Mathematical derivatization of the chromatograms offered several advantages over conventional skimmed integration. A combination of the second derivative amplitude and simple linear regression gave a novel method for estimating the true peak area of the impurity peak. All the calculation steps were carried out using a widely available spreadsheet program. (C) 2003 Elsevier B.V. All rights reserved
Treatment of dogs with compensated myxomatous mitral valve disease with spironolactone-a pilot study
Spironolactone improves outcome in dogs with advanced myxomatous mitral valve disease (MMVD). Its efficacy in preclinical MMVD is unknown. The hypothesis was the administration of spironolactone to dogs with compensated MMVD demonstrating risk factors for poorer prognosis will decrease the rate of disease progression. The aim was to provide pilot data to evaluate preliminary effects and sample size calculation for a definitive clinical trial
The Lipkin Model in the su(M+1)-Algebra for Many-Fermion System and its Counterpart in the Schwinger Boson Representation
Following the Schwinger boson representation for the su(M+1)- and the
su(N,1)-algebra presented by two of the present authors (J. da P. and M. Y.)
and Kuriyama, a possible counterpart of the Lipkin model in the su(M+1)-algebra
formulated in the fermion space is presented. The free vacuum, which plays a
fundamental role in the conventional treatment of the Lipkin model, is
generalized in a quite natural way, and further, the excited state generating
operators such as the particle-hole pairs are also given in a natural scheme.
As concrete examples, the cases of the su(2)-, su(3)- and the su(4)-algebra are
discussed. Especially, the case of the su(4)-algebra is investigated in detail
in relation to the nucleon pairing correlations and the high temperature
superconductivity.Comment: 22 pages, 1 figure, using PTPTeX styl
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