487 research outputs found
A Phase Transition for Circle Maps and Cherry Flows
We study weakly order preserving circle maps with a flat interval.
The main result of the paper is about a sharp transition from degenerate
geometry to bounded geometry depending on the degree of the singularities at
the boundary of the flat interval. We prove that the non-wandering set has zero
Hausdorff dimension in the case of degenerate geometry and it has Hausdorff
dimension strictly greater than zero in the case of bounded geometry. Our
results about circle maps allow to establish a sharp phase transition in the
dynamics of Cherry flows
Polarization effects in tau production by neutrino
We studied polarization effects in tau production by neutrino-nucleon
scattering. Quasi-elastic scattering, resonance production and deep
inelastic scattering processes are taken into account for the CERN-to-Gran
Sasso projects. We show that the tau produced by neutrino has high degree of
polarization, and its spin direction depends non-trivially on the energy and
the scattering angle of tau in the laboratory frame.Comment: 6 pages, 5 eps figures, espcrc2.sty; Proceedings of the 3rd
International Workshop on Neutrino-Nucleus Interactions in the Few GeV Region
(NuInt04), March 17-21, 2004, Gran Sasso, Italy; minor changes, typos in Eq.
(6) correcte
The role of the Swiss list of occupational diseases in the protection of workers' health.
Occupational disease lists (ODLs) are essential legal mechanisms for recognising pathologies related to exposure to occupational hazards. In 2017, Switzerland revised its ODL and solicited stakeholders to review the ODL proposal. This revision represented an important and rare event, and was an opportunity to assess the legal status and role of Swiss ODL. In this research, we examined the structure and content of this revised Swiss list, by comparing it to other official recommendations and ODLs, including those of the International Labour Organization (ILO) and the European Commission (EC). In addition, we assessed the effectiveness of the Swiss ODL from the occupational and public health perspectives, in considering the process of reporting and recognition of occupational diseases as a measure for protecting the health of workers. Although the Swiss ODL appears to be in accordance with the ILO and EC recommendations, its role as a legal mechanism of workers’ protection is not optimal. Its effectiveness is limited by the conditions for recognising a disease as occupational, which are determined by Swiss federal law and are stricter than in other countries. The overall burden of occupational diseases has a significant economic, social and moral impact on working populations, their families and society as a whole. As such, more transparency with respect to the ODL revision and conditions for recognising occupational disease and to the data on recognised and reported cases, along with continuous education of physicians are required to enhance the effectiveness of the Swiss system of recognition and reporting of occupational diseases and protection of Swiss workers
Complex maps without invariant densities
We consider complex polynomials for and
, and find some combinatorial types and values of such that
there is no invariant probability measure equivalent to conformal measure on
the Julia set. This holds for particular Fibonacci-like and Feigenbaum
combinatorial types when sufficiently large and also for a class of
`long-branched' maps of any critical order.Comment: Typos corrected, minor changes, principally to Section
Improving the surface brightness-color relation for early-type stars using optical interferometry
The aim of this work is to improve the SBC relation for early-type stars in
the color domain, using optical interferometry.
Observations of eight B- and A-type stars were secured with the VEGA/CHARA
instrument in the visible. The derived uniform disk angular diameters were
converted into limb darkened angular diameters and included in a larger sample
of 24 stars, already observed by interferometry, in order to derive a revised
empirical relation for O, B, A spectral type stars with a V-K color index
ranging from -1 to 0. We also took the opportunity to check the consistency of
the SBC relation up to using 100 additional measurements. We
determined the uniform disk angular diameter for the eight following stars:
Ori, Per, Cyg, Her, Aql, Peg,
Lyr, and Cyg with V-K color ranging from -0.70 to 0.02 and
typical precision of about . Using our total sample of 132 stars with
colors index ranging from about to , we provide a revised SBC
relation. For late-type stars (), the results are consistent
with previous studies. For early-type stars (), our new
VEGA/CHARA measurements combined with a careful selection of the stars
(rejecting stars with environment or stars with a strong variability), allows
us to reach an unprecedented precision of about 0.16 magnitude or
in terms of angular diameter.Comment: 13 pages, 5 figures, accepted for publication in A&
Natural equilibrium states for multimodal maps
This paper is devoted to the study of the thermodynamic formalism for a class
of real multimodal maps. This class contains, but it is larger than,
Collet-Eckmann. For a map in this class, we prove existence and uniqueness of
equilibrium states for the geometric potentials , for the largest
possible interval of parameters . We also study the regularity and convexity
properties of the pressure function, completely characterising the first order
phase transitions. Results concerning the existence of absolutely continuous
invariant measures with respect to the Lebesgue measure are also obtained
On the Lebesgue measure of Li-Yorke pairs for interval maps
We investigate the prevalence of Li-Yorke pairs for and
multimodal maps with non-flat critical points. We show that every
measurable scrambled set has zero Lebesgue measure and that all strongly
wandering sets have zero Lebesgue measure, as does the set of pairs of
asymptotic (but not asymptotically periodic) points.
If is topologically mixing and has no Cantor attractor, then typical
(w.r.t. two-dimensional Lebesgue measure) pairs are Li-Yorke; if additionally
admits an absolutely continuous invariant probability measure (acip), then
typical pairs have a dense orbit for . These results make use of
so-called nice neighborhoods of the critical set of general multimodal maps,
and hence uniformly expanding Markov induced maps, the existence of either is
proved in this paper as well.
For the setting where has a Cantor attractor, we present a trichotomy
explaining when the set of Li-Yorke pairs and distal pairs have positive
two-dimensional Lebesgue measure.Comment: 41 pages, 3 figure
Abundance Analyses of Field RV Tauri Stars, VI: An Extended Sample
An abundance analysis is presented and discussed for a sample of 14 RV Tauri
stars. The present abundance data and those from our previous papers and by
other workers are combined in an attempt to further understanding of the
dust-gas separation process which afflicts many RV Tauri variables. We propose
that a star's intrinsic (i.e., initial) metallicity is given by the
photospheric zinc abundance. Variables warmer that about 5000 K and with an
initial metallicity [Fe/H] 1 are affected by dust-gas separation.
Variables of all metallicities and cooler than about
K are unaffected by dust-gas separation. The RV Tauri variables show a spread
in their C abundances with the lower boundary of the points in the C versus Zn
plane falling close to the predicted trend for giants after the first
dredge-up. The upper boundary is inhabited by a few stars that are carbon-rich.
The O abundances in the mean follow the predicted trend from unevolved stars in
line with the expectation that photospheric O abundance is unaffected by the
first dredge-up. An evolutionary scenario involving mass loss by a first ascent
or early-AGB red giant, the primary star of a binary, is sketched.Comment: 42 pages (including 13 figures), Accepted for Publication in Ap
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