Evolutionary Models of the Dissociation Zones Surrounding HII Regions

1987 ◽  
pp. 203-204
Author(s):  
R. S. Roger ◽  
P. E. Dewdney
Keyword(s):  
Hii Regions ◽  
Evolutionary Models

Comparison of U BV R photometry of giant HII regions in the galaxy NGC 628 with a detailed grid of evolutionary models for star clusters

2007 ◽  
Vol 51 (3) ◽  
pp. 222-233 ◽  
Author(s):  
V. V. Bruevich ◽  
A. S. Gusev ◽  
O. V. Ezhkova ◽  
F. Kh. Sakhibov ◽  
M. A. Smirnov
Keyword(s):  
Star Clusters ◽  
Hii Regions ◽  
Evolutionary Models ◽  
The Galaxy

scholarly journals Evolutionary Models of the Dissociation Zones Surrounding HII Regions

1987 ◽  
Vol 115 ◽  
pp. 203-204
Author(s):  
R. S. Roger ◽  
P. E. Dewdney
Keyword(s):  
Atomic Hydrogen ◽  
Vibrational State ◽  
Computer Modelling ◽  
Hii Regions ◽  
Evolutionary Models ◽  
Gas Density ◽  
Ground Vibrational State ◽  
Ambient Gas

Atomic hydrogen regions have been observed in λ21-cm emission around a number of galactic HII regions in various stages of evolution (Roger & Pedlar, 1981; Dewdney & Roger, 1982; Roger & Irwin, 1982). These HI zones are almost certainly formed by the dissociation of H2 with Lyman-Werner band photons in the UV from the exciting stars. We describe some results of the computer modelling of the advancement of dissociation fronts with time as functions of various parameters, principally stellar type and ambient gas density. The modelling has shown that for most conditions a substantial HI zone is formed fairly rapidly around a new star. When the dissociation front moves out to a distance where absorbing molecules are predominantly in the ground vibrational state, further advancement of the front is much slower.

COLLIDING IONIZATION FRONTS I. IONIZED SHELLS IN HII REGIONS

1978 ◽  
Vol 39 (C1) ◽  
pp. C1-168-C1-168
Author(s):  
G. TENORIO-TAGLE
Keyword(s):  
Hii Regions ◽  
Ionization Fronts

Social cognition and brain organization in chimpanzees (Pan troglodytes) and bonobos (Pan paniscus)

2018 ◽  
Author(s):  
William D. Hopkins ◽  
Cheryl D. Stimpson ◽  
Chet C. Sherwood
Keyword(s):  
Social Cognition ◽  
Social Behaviour ◽  
Grey Matter ◽  
Species Differences ◽  
Pan Paniscus ◽  
Grey Matter Volume ◽  
Evolutionary Models ◽  
Brain Organization ◽  
Matter Volume ◽  
Cognition Sociale

Bonobos and chimpanzees are two closely relates species of the genus Pan, yet they exhibit marked differences in anatomy, behaviour and cognition. For this reason, comparative studies on social behaviour, cognition and brain organization between these two species provide important insights into evolutionary models of human origins. This chapter summarizes studies on socio-communicative competencies and social cognition in chimpanzees and bonobos from the authors’ laboratory in comparison to previous reports. Additionally, recent data on species differences and similarities in brain organization in grey matter volume and distribution is presented. Some preliminary findings on microstructural brain organization such as neuropil space and cellular distribution in key neurotransmitters and neuropeptides involved in social behaviour and cognition is presented. Though these studies are in their infancy, the findings point to potentially important differences in brain organization that may underlie bonobo and chimpanzees’ differences in social behaviour, communication and cognition. Les bonobos et les chimpanzés sont deux espèces du genus Pan prochement liées, néanmoins ils montrent des différences anatomiques, comportementales et cognitives marquées. Pour cette raison, les études comparatives sur le comportement social, la cognition et l’organisation corticale entre ces deux espèces fournissent des idées sur les modèles évolutionnaires des origines humaines. Dans ce chapitre, nous résumons des études sur les compétences socio-communicatives et la cognition sociale chez les chimpanzés et les bonobos de notre laboratoire en comparaison avec des rapports précédents. En plus, nous présentons des données récentes sur les différences et similarités d’organisation corticale du volume et distribution de la matière grise entre espèces. Nous présentons plus de résultats préliminaires sur l’organisation corticale microstructurale comme l’espace neuropile et la division cellulaire dans des neurotransmetteurs clés et les neuropeptides impliqués dans le comportement social et la cognition. Bien que ces études sont dans leur enfance, les résultats montrent des différences d’organisation corticale importantes qui sont à la base des différences de comportement social, la communication et la cognition entre les bonobos et les chimpanzés.

Preliminary Observations of Interstellar Sodium D-Line Absorption towards the Carina Nebula

1980 ◽  
Vol 4 (1) ◽  
pp. 95-97 ◽  
Author(s):  
J. B. Whiteoak ◽  
F. F. Gardner
Keyword(s):  
High Resolution ◽  
Hii Regions ◽  
Early Type ◽  
Interstellar Clouds ◽  
Carina Nebula ◽  
Line Absorption ◽  
General Investigation ◽  
Early Type Stars ◽  
Resolution Study

As part of a general investigation of interstellar clouds associated with southern HII regions we have begun a high-resolution study of the sodium D-line absorption in the directions of early-type stars that are likely to be associated with or located behind the clouds.

scholarly journals Evolutionary Models for 43 Galactic Supernova Remnants with Distances and X-Ray Spectra

2020 ◽  
Vol 248 (1) ◽  
pp. 16 ◽  
Author(s):  
D. A. Leahy ◽  
S. Ranasinghe ◽  
M. Gelowitz
Keyword(s):  
Supernova Remnants ◽  
Evolutionary Models ◽  
X Ray
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