scholarly journals What is the connection between ellipticals and bulges?

1993 ◽  
Vol 153 ◽  
pp. 243-262 ◽  
Author(s):  
Marijn Franx
Keyword(s):  
Quantitative Variation ◽  
Galaxy Halos ◽  
Stellar Formation ◽  
Velocity Dispersions ◽  
Qualitative Distinction

The structure of bulges and ellipticals, and their relation to galaxy halos are reviewed. Since many ellipticals contain faint disks, the qualitative distinction between bulges and ellipticals is more accurately described as a quantitative variation in Bulge/Disk ratio. The exception may be the brightest ellipticals, which are usually Bright (est) Cluster Members. The available evidence suggests that the spheroid properties are determined by more than halo properties alone. This is clearest for systems with low B/D ratio, where bulge velocity dispersions are similar to disk velocity dispersions. Constraints on the stellar formation scenarios are discussed.

GENETIC HETEROGENEITY OF RABBIT ALPHA-1-ANTITRYPSIN

Genetics ◽  
1984 ◽  
Vol 106 (4) ◽  
pp. 695-703
Author(s):  
F Kueppers ◽  
C C Lee ◽  
R R Fox ◽  
J K Mills
Keyword(s):  
Sexual Dimorphism ◽  
Genetic Heterogeneity ◽  
Inbred Strains ◽  
Quantitative Variation ◽  
Moderate Degree ◽  
Inhibiting Activity ◽  
Interindividual Differences ◽  
Alpha 1 Antitrypsin ◽  
Serum Trypsin

ABSTRACT Sixteen inbred or partially inbred strains of rabbits were investigated for electrophoretic and quantitative variations of alpha-1-antitrypsin (A-1-AT). We found interindividual differences in the electrophoretic A-1-AT patterns as well as quantitative differences in the concentrations of A-1-AT and the serum trypsin-inhibiting activity. Three electrophoretic phenotypes were distinguished: M, P and MP. M was characterized by a predominant anodal A-1-AT band, and P had a major cathodal component. The MP pattern can be explained by the occurrence of the M and P components in the same serum due to heterozygosity. The P pattern was associated with an A-1-AT concentration of approximately 56% of that in sera with the M phenotype. The levels of A-1-AT in sera with the MP phenotype were intermediate between those in M and P types. In addition to the type-specific quantitative variation, we found a quantitative sexual dimorphism of a moderate degree: Female rabbits had A-1-AT concentrations 16% less than males.

Is neutral genetic diversity related to quantitative variation in semen traits in bulls?

2021 ◽  
Author(s):  
Eddington Gororo ◽  
Fungayi Primrose Chatiza ◽  
Farisai Chidzwondo ◽  
Stanley Marshall Makuza
Keyword(s):  
Genetic Diversity ◽  
Quantitative Variation ◽  
Neutral Genetic Diversity

scholarly journals Hybrid dysgenesis-induced quantitative variation on the X chromosome of Drosophila melanogaster.

Genetics ◽  
1990 ◽  
Vol 124 (3) ◽  
pp. 627-636
Author(s):  
C Q Lai ◽  
T F Mackay
Keyword(s):  
Drosophila Melanogaster ◽  
X Chromosome ◽  
Quantitative Traits ◽  
Natural Populations ◽  
Quantitative Variation ◽  
Hybrid Dysgenesis ◽  
X Chromosomes ◽  
Bristle Number ◽  
Seven Generations ◽  
Polygenic Variation

Abstract To determine the ability of the P-M hybrid dysgenesis system of Drosophila melanogaster to generate mutations affecting quantitative traits, X chromosome lines were constructed in which replicates of isogenic M and P strain X chromosomes were exposed to a dysgenic cross, a nondysgenic cross, or a control cross, and recovered in common autosomal backgrounds. Mutational heritabilities of abdominal and sternopleural bristle score were in general exceptionally high-of the same magnitude as heritabilities of these traits in natural populations. P strain chromosomes were eight times more mutable than M strain chromosomes, and dysgenic crosses three times more effective than nondysgenic crosses in inducing polygenic variation. However, mutational heritabilities of the bristle traits were appreciable for P strain chromosomes passed through one nondysgenic cross, and for M strain chromosomes backcrossed for seven generations to inbred P strain females, a result consistent with previous observations on mutations affecting quantitative traits arising from nondysgenic crosses. The new variation resulting from one generation of mutagenesis was caused by a few lines with large effects on bristle score, and all mutations reduced bristle number.

scholarly journals Most of the cool CGM of star-forming galaxies is not produced by supernova feedback

2020 ◽  
Author(s):  
Andrea Afruni ◽  
Filippo Fraternali ◽  
Gabriele Pezzulli
Keyword(s):  
Galaxy Evolution ◽  
Cosmic Time ◽  
Energy Coupling ◽  
High Energy ◽  
Parametric Models ◽  
Star Forming ◽  
Galaxy Halos ◽  
The Galaxy ◽  
Supernova Explosions ◽  
Cool Gas

Abstract The characterization of the large amount of gas residing in the galaxy halos, the so called circumgalactic medium (CGM), is crucial to understand galaxy evolution across cosmic time. We focus here on the the cool (T ∼ 104 K) phase of this medium around star-forming galaxies in the local universe, whose properties and dynamics are poorly understood. We developed semi-analytical parametric models to describe the cool CGM as an outflow of gas clouds from the central galaxy, as a result of supernova explosions in the disc (galactic wind). The cloud motion is driven by the galaxy gravitational pull and by the interactions with the hot (T ∼ 106 K) coronal gas. Through a bayesian analysis, we compare the predictions of our models with the data of the COS-Halos and COS-GASS surveys, which provide accurate kinematic information of the cool CGM around more than 40 low-redshift star-forming galaxies, probing distances up to the galaxy virial radii. Our findings clearly show that a supernova-driven outflow model is not suitable to describe the dynamics of the cool circumgalactic gas. Indeed, to reproduce the data, we need extreme scenarios, with initial outflow velocities and mass loading factors that would lead to unphysically high energy coupling from the supernovae to the gas and with supernova efficiencies largely exceeding unity. This strongly suggests that, since the outflows cannot reproduce most of the cool gas absorbers, the latter are likely the result of cosmological inflow in the outer galaxy halos, in analogy to what we have previously found for early-type galaxies.

On the Formation of Galaxy Halos: Comparing NGC 5128 and the Local Group Members

2001 ◽  
Vol 122 (6) ◽  
pp. 3065-3069 ◽  
Author(s):  
William E. Harris ◽  
Gretchen L. H. Harris
Keyword(s):  
Local Group ◽  
Galaxy Halos ◽  
Group Members
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