6,242 research outputs found
Peeling Bifurcations of Toroidal Chaotic Attractors
Chaotic attractors with toroidal topology (van der Pol attractor) have
counterparts with symmetry that exhibit unfamiliar phenomena. We investigate
double covers of toroidal attractors, discuss changes in their morphology under
correlated peeling bifurcations, describe their topological structures and the
changes undergone as a symmetry axis crosses the original attractor, and
indicate how the symbol name of a trajectory in the original lifts to one in
the cover. Covering orbits are described using a powerful synthesis of kneading
theory with refinements of the circle map. These methods are applied to a
simple version of the van der Pol oscillator.Comment: 7 pages, 14 figures, accepted to Physical Review
Changes in Body Measurements of Heifers at First Parturition
Author Institution: Department of Dairy Science, Ohio Agricultural Experiment Station, Wooste
Generalized coherent states are unique Bell states of quantum systems with Lie group symmetries
We consider quantum systems, whose dynamical symmetry groups are semisimple
Lie groups, which can be split or decay into two subsystems of the same
symmetry. We prove that the only states of such a system that factorize upon
splitting are the generalized coherent states. Since Bell's inequality is never
violated by the direct product state, when the system prepared in the
generalized coherent state is split, no quantum correlations are created.
Therefore, the generalized coherent states are the unique Bell states, i.e.,
the pure quantum states preserving the fundamental classical property of
satisfying Bell's inequality upon splitting.Comment: 4 pages, REVTeX, amssymb style. More information on
http://www.technion.ac.il/~brif/science.htm
Earnestly Finding the Fun in Fund Codes
Collections and acquisitions staff at Virginia Tech and The University of Alabama presented two very different models for structuring fund codes and discussed the benefits and difficulties inherent to each method. Both groups share their philosophy and approach for allocating appropriate fund codes for budgeting, reporting, and analytical purposes, and highlight important considerations to be made when creating a fund code structure
Phase transitions with finite atom number in the Dicke Model
Two-level atoms interacting with a one mode cavity field at zero temperature
have order parameters which reflect the presence of a quantum phase transition
at a critical value of the atom-cavity coupling strength. Two popular examples
are the number of photons inside the cavity and the number of excited atoms.
Coherent states provide a mean field description, which becomes exact in the
thermodynamic limit. Employing symmetry adapted (SA) SU(2) coherent states
(SACS) the critical behavior can be described for a finite number of atoms. A
variation after projection treatment, involving a numerical minimization of the
SA energy surface, associates the finite number phase transition with a
discontinuity in the order parameters, which originates from a competition
between two local minima in the SA energy surface.Comment: 8 pages, 10 figures, Conference Proceedings of CEWQO-2012, to be
published as a Topical Issue of the journal Physica Script
OB Stars in the Solar Neighborhood I: Analysis of their Spatial Distribution
We present a newly-developed, three-dimensional spatial classification
method, designed to analyze the spatial distribution of early type stars within
the 1 kpc sphere around the Sun. We propose a distribution model formed by two
intersecting disks -the Gould Belt (GB) and the Local Galactic Disk (LGD)-
defined by their fundamental geometric parameters. Then, using a sample of
about 550 stars of spectral types earlier than B6 and luminosity classes
between III and V, with precise photometric distances of less than 1 kpc, we
estimate for some spectral groups the parameters of our model, as well as
single membership probabilities of GB and LGD stars, thus drawing a picture of
the spatial distribution of young stars in the vicinity of the Sun.Comment: 28 pages including 9 Postscript figures, one of them in color.
Accepted for publication in The Astronomical Journal, 30 January 200
Synchronous Evolution of Galaxies in Groups: NGC 524 Group
By means of panoramic spectroscopy at the SAO RAS BTA telescope, we
investigated the properties of stellar populations in the central regions of
five early-type galaxies -- the NGC 524 group members. The evolution of the
central regions of galaxies looks synchronized: the average age of stars in the
bulges of all the five galaxies lies in the range of 3--6 Gyr. Four of the five
galaxies revealed synchronized bursts of star formation in the nuclei 1--2 Gyr
ago. The only galaxy, in which the ages of stellar population in the nucleus
and in the bulge coincide (i.e. the nuclear burst of star formation did not
take place) is NGC 502, the farthest from the center of the group of all the
galaxies studied.Comment: Slightly edited version of the paper to appear in the Astrophysical
Bulletin, 67(3); 24 pages including 8 figure
Influence of household demographic and socio-economic factors on household expenditure on tobacco in six New Independent States
<p>Abstract</p> <p>Background</p> <p>To identify demographic and socio-economic factors that are associated with household expenditure on tobacco in Azerbaijan, Georgia, Kazakhstan, Kyrgyzstan, Russian Federation, and Tajikistan.</p> <p>Methods</p> <p>Secondary analysis of the data available through the World Bank Living Standards Monitoring Survey conducted in aforementioned countries in 1995–2000. The role of different variables (e.g. mean age of household members, household area of residence, household size, share of adult males, share of members with high education) in determining household expenditure on tobacco (defined as tobacco expenditure share out of total monthly HH consumption) was assessed by using multiple regression analysis.</p> <p>Results</p> <p>Significant differences were found between mean expenditure on tobacco between rich and poor – in absolute terms the rich spend significantly more compared with the poor. Poor households devote significantly higher shares of their monthly HH consumption for tobacco products. Shares of adult males were significantly associated with the share of household consumption devoted for tobacco. There was a significant negative association between shares of persons with tertiary education within the HH and shares of monthly household consumption devoted for tobacco products. The correlation between household expenditures on tobacco and alcohol was found to be positive, rather weak, but statistically significant.</p> <p>Conclusion</p> <p>Given the high levels of poverty and high rates of smoking in the New Independent States, these findings have important policy implications. They indicate that the impact and opportunity costs of smoking on household finances are more significant for the poor than for the rich. Any reductions in smoking prevalence within poor households could have a positive economic impact.</p
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