1,489 research outputs found
Application of Monte Carlo-based statistical significance determinations to the Beta Cephei stars V400 Car, V401 Car, V403 Car and V405 Car
We have used Lomb-Scargle periodogram analysis and Monte Carlo significance
tests to detect periodicities above the 3-sigma level in the Beta Cephei stars
V400 Car, V401 Car, V403 Car and V405 Car. These methods produce six previously
unreported periodicities in the expected frequency range of excited pulsations:
one in V400 Car, three in V401 Car, one in V403 Car and one in V405 Car. One of
these six frequencies is significant above the 4-sigma level. We provide
statistical significances for all of the periodicities found in these four
stars.Comment: 11 pages, 17 figure
Charge-Spin Separation in 2D Fermi Systems: Singular Interactions as Modified Commutators, and Solution of 2D Hubbard Model in Bosonized Approximation
The general 2-dimensional fermion system with repulsive interactions
(typified by the Hubbard Model) is bosonized, taking into account the finite
on-shell forward scattering phase shift derived in earlier papers. By taking
this phase shift into account in the bosonic commutation relations a consistent
picture emerges showing the charge-spin separation and anomalous exponents of
the Luttinger liquid.Comment: Latex file 14 pages. email: [email protected]
Die betroubaarheid en faktorstruktuur van die aangepaste meervoudige keuse-formaat van die miner sentence completion scale (MSCS)
The original publication is available at http://www.sajip.co.zaThe reliability and factor structure of the adapted multiple choice version of the Miner Sentence Completion Scale (MSCS). In this study the multiple choice MSCS was adapted as a result of several criticisms thereof. The internal consistency and factor structure of the adapted MSCS were determined to ascertain the reliability and construct validity of the questionnaire. Results show that the internal consistency is unsatisfactory and that the factor structure is so complex that interpretation becomes virtually impossible. In light of the results of this study and other research findings of the psychometric properties of the MSCS, it is recommended that a new measuring instrument for managerial motivation be developed that will enable a valid testing of the managerial rolemotivation theory.Na aanleiding van verskeie punte van kritiek teen die MSCS is die meervoudige keuse-MSCS in hierdie studie aangepas. Ten einde 'n aanduiding van die betroubaarheid en konstrukgeldigheid van die aangepaste MSCS te verkry, is die interne konsekwentheid en faktorstruktuur daarvan bepaal. Die resultate dui daarop dat die interne konsekwentheid onbevredigend en die faktorstruktuur te kompleks vir interpretasie is. In die lig van die bevindinge van hierdie studie, en ander navorsingsbevindinge oor die psigometriese eienskappe van die MSCS, word aanbeveel dat 'n nuwe meetinstrument van bestuursmotivering ontwikkel word wat 'n geldige toetsing van die bestuursrol-motiveringsteorie moontlik sal maak.Publishers' Versio
Dynamical Phase Transitions In Driven Integrate-And-Fire Neurons
We explore the dynamics of an integrate-and-fire neuron with an oscillatory
stimulus. The frustration due to the competition between the neuron's natural
firing period and that of the oscillatory rhythm, leads to a rich structure of
asymptotic phase locking patterns and ordering dynamics. The phase transitions
between these states can be classified as either tangent or discontinuous
bifurcations, each with its own characteristic scaling laws. The discontinuous
bifurcations exhibit a new kind of phase transition that may be viewed as
intermediate between continuous and first order, while tangent bifurcations
behave like continuous transitions with a diverging coherence scale.Comment: 4 pages, 5 figure
An Efficient Algorithm for Optimizing Adaptive Quantum Metrology Processes
Quantum-enhanced metrology infers an unknown quantity with accuracy beyond
the standard quantum limit (SQL). Feedback-based metrological techniques are
promising for beating the SQL but devising the feedback procedures is difficult
and inefficient. Here we introduce an efficient self-learning
swarm-intelligence algorithm for devising feedback-based quantum metrological
procedures. Our algorithm can be trained with simulated or real-world trials
and accommodates experimental imperfections, losses, and decoherence
Density-induced BCS to Bose-Einstein crossover
We investigate the zero-temperature BCS to Bose-Einstein crossover at the
mean-field level, by driving it with the attractive potential and the particle
density.We emphasize specifically the role played by the particle density in
this crossover.Three different interparticle potentials are considered for the
continuum model in three spatial dimensions, while both s- and d-wave solutions
are analyzed for the attractive (extended) Hubbard model on a two-dimensional
square lattice. For this model the peculiar behavior of the crossover for the
d-wave solution is discussed.In particular, in the strong-coupling limit when
approaching half filling we evidence the occurrence of strong correlations
among antiparallel-spin fermions belonging to different composite bosons, which
give rise to a quasi-long-range antiferromagnetic order in this limit.Comment: 10 pages, 5 enclosed figure
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