5,050 research outputs found
Axial rotation and turbulence of RR ab stars: the Peterson Conundrum revisited
We calibrate and then use the relation between equivalent width (EW) and
full-width-half-maximum (FWHM) of metallic absorption lines in the spectra of
RR Lyrae stars to estimate a new upper limit of Vrot sini less than or equal to
6 km/s on their axial equatorial rotational velocities, and to derive the
variations of macroturbulent velocities in their atmospheres during pulsation
cycles. Finally, we present a simple way to estimate macroturbulent/rotational
velocity from FWHM of the cross-correlation function.Comment: 15 pages, 7 figures, 1 table. EAS Publications Series.: "New advances
in stellar physics: from microscopic to macroscopic processes", 27-31 May
2013, Roscoff, Franc
Part I. Synthesis of Tumour-Inhibiting Compounds. Part II. Synthesis of 1:9-Phenylenecarbazole
Abstract Not Provided
Recommended from our members
IT Alignment with Business Strategies in Healthcare Organizations: An Empirical Analysis
This paper describes a study that assessed the performance implications of aligning information technology (IT) strategy to overall business strategy across a variety of health care organization (HCO) structures. We obtained survey results from senior executives of 178 hospitals to identify key configurations of IT strategic practices, business strategy and HCO structures. Using K- means cluster analysis, we identified which business strategies correlate strongly with certain IT strategy types. Our results indicate that HCOs achieve superior performance through unique combinations of business and IT strategy, suggesting that correctly aligning these strategies is a critical decision for healthcare organizations
AVALIANDO JULGAMENTOS NÃO VERBAIS DE IGUALDADE/DIFERENÇA ENTRE ESTÍMULOS AUDITIVOS EM INDIVÍDUOS COM DEFICIÊNCIAS INTELECTUAIS: UMA INVESTIGAÇÃO METODOLÓGICA
This methodological paper reports an initial attempt to evaluate the feasibility and utility of a nonverbal task for assessing generalized same/different judgments of auditory stimuli in individuals with intellectual disabilities. Study 1 asked whether participants could readily acquire a baseline of auditory same/different, go-left/go-right performance with minimal prompting. Sample stimuli consisted of pairs of successively presented sine-wave tones. If the tones were identical, selections of a visual stimulus on the left side of the computer screen were reinforced. If the tones were different, selections of a visual stimulus on the right side of the computer screen were reinforced. Two of five participants readily acquired the task, generalized performance to other stimuli, and completed a rudimentary protocol for examining auditory discriminations that are potentially more difficult than those used to establish the initial task. In Study 2, two participants who could not perform the “go-left/go-right” task with tone stimuli, but could do so with spoken-word stimuli, successfully transferred control by spoken words to tones via an auditory superimposition-and-fading procedure. The findings support the feasibility of using the task as a general-purpose auditory discrimination assessment.Keywords: auditory discrimination, go-left/go-right, intellectual disabilities, matching to sample, superimposition and fading.O presente artigo metodológico relata uma tentativa inicial de avaliar a viabilidade e a utilidade de uma tarefa não verbal para avaliar o julgamento generalizado de igualdade/diferença entre estímulos auditivos em indivíduos com deficiências intelectuais. O Estudo 1 investigou se os participantes poderiam prontamente adquirir uma linha de base de desempenho discriminativo de igualdade/diferença, em tarefa de “go-left/go-right” (responder à esquerda/responder à direita) com ajuda mínima. Os estímulos-modelo consistiam em pares de sons de frequência única apresentados sucessivamente. Se os sons fossem idênticos, seleções de um estímulo visual no lado esquerdo da tela do computador eram reforçadas. Se os sons fossem diferentes, seleções de um estímulo visual no lado direito da tela do computador eram reforçadas. Dois dos cinco participantes aprenderam prontamente a tarefa, generalizaram o desempenho para outros estímulos e completaram um protocolo rudimentar para avaliar discriminações auditivas que são potencialmente mais difíceis do que aquelas usadas para estabelecer a tarefa inicial. No Estudo 2, dois participantes que não puderam desempenhar a tarefa “go-left/go-right” com os sons de única frequência, mas puderam fazê-lo com palavras faladas como estímulos, transferiram com sucesso o controle das palavras faladas para os sons via um procedimento de esmaecimento e sobreposição de estímulos auditivos. Os achados apoiam a viabilidade de se usar a tarefa como uma avaliação de discriminação auditiva em geral. Palavras-chave: discriminação auditiva, procedimento de resposta à esquerda/resposta à direita, deficiência intelectual, emparelhamento ao modelo, sobreposição e esmaecimento
Probabilistic computer model of optimal runway turnoffs
Landing delays are currently a problem at major air carrier airports and many forecasters agree that airport congestion will get worse by the end of the century. It is anticipated that some types of delays can be reduced by an efficient optimal runway exist system allowing increased approach volumes necessary at congested airports. A computerized Probabilistic Runway Turnoff Model which locates exits and defines path geometry for a selected maximum occupancy time appropriate for each TERPS aircraft category is defined. The model includes an algorithm for lateral ride comfort limits
Spectroscopic Constraints on the Surface Magnetic Field of the Accreting Neutron Star EXO 0748-676
Gravitationally redshifted absorption lines of Fe XXVI, Fe XXV, and O VIII
were inferred recently in the X-ray spectrum of the bursting neutron star EXO
0748-676. We place an upper limit on the stellar magnetic field based on the
iron lines. The oxygen absorption feature shows a multiple component profile
that is consistent with Zeeman splitting in a magnetic field of ~(1-2)x10^9
gauss, and for which the corresponding Zeeman components of the iron lines are
expected to be blended together. In other systems, a field strength >5x10^{10}
gauss could induce a blueshift of the line centroids that would counteract
gravitational redshift and complicate the derivation of constraints on the
equation of state of the neutron star.Comment: 5 pages, submitted to Phys. Rev. Let
Field Blue Stragglers and Related Mass Transfer Issues
This chapter contains my impressions and perspectives about the current state
of knowledge about field blue stragglers (FBS) stars, drawn from an extensive
literature that I searched. I conclude my review of issues that attend FBS and
mass transfer, by a brief enumeration of a few mildly disquieting observational
facts.Comment: Chapter 4, in Ecology of Blue Straggler Stars, H.M.J. Boffin, G.
Carraro & G. Beccari (Eds), Astrophysics and Space Science Library, Springe
Comparison of statistical treatments for the equation of state for core-collapse supernovae
Neutrinos emitted during the collapse, bounce and subsequent explosion
provide information about supernova dynamics. The neutrino spectra are
determined by weak interactions with nuclei and nucleons in the inner regions
of the star, and thus the neutrino spectra are determined by the composition of
matter. The composition of stellar matter at temperature ranging from
MeV and densities ranging from to 0.1 times the saturation density is
explored. We examine the single-nucleus approximation commonly used in
describing dense matter in supernova simulations and show that, while the
approximation is accurate for predicting the energy and pressure at most
densities, it fails to predict the composition accurately. We find that as the
temperature and density increase, the single nucleus approximation
systematically overpredicts the mass number of nuclei that are actually present
and underestimates the contribution from lighter nuclei which are present in
significant amounts.Comment: 12 pages, 11 figure
- …