295 research outputs found
The Relationship between Brachycephalic Head Features in Modern Persian Cats and Dysmorphologies of the Skull and Internal Hydrocephalus
Background: Cat breeders observed a frequent occurrence of internal hydrocephalus in Persian cats with extreme brachycephalic head morphology. Objective: To investigate a possible relationship among the grade of brachycephaly, ventricular dilatation, and skull dysmorphologies in Persian cats. Animals: 92 Persian-, 10 Domestic shorthair cats. Methods: The grade of brachycephaly was determined on skull models based on CT datasets. Cranial measurements were examined with regard to a possible correlation with relative ventricular volume, and cranial capacity. Persians with high (peke-face Persians) and lower grades of brachycephaly (doll-face Persians) were investigated for the presence of skull dysmorphologies.
Results: The mean cranial index of the peke-face Persians (0.97 ± 0.14) was significantly higher than the mean cranial index of doll-face Persians (0.66 ± 0.04; P < 0.001). Peke-face Persians had a lower relative nasal bone length (0.15 ± 0.04) compared to doll-face (0.29 ± 0.08; P < 0.001). The endocranial volume was significantly lower in doll-face than peke-face Persians (89.6 ± 1.27% versus 91.76 ± 2.07%; P < 0.001). The cranial index was significantly correlated with this variable (SpearmanŽs r: 0.7; P < 0.0001).
Mean ventricle: Brain ratio of the peke-face group (0.159 ± 0.14) was significantly higher compared to doll-face Persians (0.015 ± 0.01; P < 0.001). Conclusion and Clinical Relevance: High grades of brachycephaly are also associated with malformations of the calvarial and facial bones as well as dental malformations. As these dysmorphologies can affect animal welfare, the selection for extreme forms of brachycephaly in Persian cats should be reconsidered
Spatially resolved spectroscopy of Coma cluster early-type galaxies IV. Completing the dataset
The long-slit spectra obtained along the minor axis, offset major axis and
diagonal axis are presented for 12 E and S0 galaxies of the Coma cluster drawn
from a magnitude-limited sample studied before. The rotation curves, velocity
dispersion profiles and the H_3 and H_4 coefficients of the Hermite
decomposition of the line of sight velocity distribution are derived. The
radial profiles of the Hbeta, Mg, and Fe line strength indices are measured
too. In addition, the surface photometry of the central regions of a subsample
of 4 galaxies recently obtained with Hubble Space Telescope is presented. The
data will be used to construct dynamical models of the galaxies and study their
stellar populations.Comment: 40 pages, 7 figures, 6 tables. Accepted for publication in ApJ
Hysteroscopic Management of an Interstitial Ectopic Pregnancy
We report a case of an interstitial ectopic pregnancy successfully managed by hysteroscopy. We highlight the benefits of using hysteroscopy, a non-invasive procedure, to preserve fertility
Stellar population gradients in Fornax Cluster S0 galaxies: connecting bulge and disk evolution
We present absorption-line index gradients for a sample of S0 galaxies in the
Fornax Cluster. The sample has been selected to span a wide range in galaxy
mass, and the deep VLT-FORS2 spectroscopy allows us to explore the stellar
populations all the way to the outer disk-dominated regions of these galaxies.
We find that globally, in both bulges and disks, star formation ceased earliest
in the most massive systems, as a further manifestation of downsizing. However,
within many galaxies, we find an age gradient which indicates that star
formation ended first in the outermost regions. Metallicity gradients, when
detected, are always negative such that the galaxy centres are more metal-rich.
This finding fits with a picture in which star formation continued in the
central regions, with enriched material, after it had stopped in the outskirts.
Age and metallicity gradients are correlated, suggesting that large differences
in star formation history between the inner and outer parts of S0 galaxies
yield large differences in their chemical enrichment. In agreement with
previous results, we conclude that the radial variations in the stellar
populations of S0 galaxies are compatible with the hypothesis that these
galaxies are the descendants of spiral galaxies whose star formation has
ceased. With the addition of radial gradient information, we are able to show
that this shutdown of star formation occurred from the outside inward, with the
later star formation in the central regions offering a plausible mechanism for
enhancing the bulge light in these systems, as the transformation to more
bulge-dominated S0 galaxies requires.Comment: 9 pages, 4 figures and Appendix, accepted for publication in MNRA
Spatially resolved spectroscopy of Coma cluster early-type galaxies - II:the minor axis dataset
We present minor axis, off set major axis and one diagonal long slit spectra for 10 E and S0 galaxies of the Coma cluster drawn from a magnitude-limited sample studied before. We derive rotation curves, velocity dispersion profiles and the H-3 and H-4 coefficients of the Hermite decomposition of the line of sight velocity distribution. Moreover, we derive the line index profiles of Mg, Fe and Hbeta line indices and assess their errors. The data will be used to construct dynamical models of the galaxies and study their stellar populations
Differences in carbon and nitrogen abundances between field and cluster early-type galaxies
Central line-strength indices were measured in the blue spectral region for a
sample of 98 early-type galaxies in different environments. For most indices
(Mgb and in particular) ellipticals in rich clusters and in low-density
regions follow the same index-sigma relations. However, striking spectral
differences between field ellipticals and their counterparts in the central
region of the Coma cluster are found for the first time, with galaxies in the
denser environment showing significantly lower C4668 and CN2 absorption
strengths. The most convincing interpretation of these results is a difference
in abundance ratios, arising from a distinct star formation and chemical
enrichment histories of galaxies in different environments. An scenario in
which elliptical galaxies in clusters are fully assembled at earlier stages
than their low-density counterparts is discussed.Comment: 12 pages, including 3 figures, accepted for publication in ApJ
A K band survey in the Groth Strip Flanking Fields
As a part of our collaboration in the COSMOS Project, devoted to the characterization of galaxies during the ep o c h of maximum star formation in the history of the Universe, we have carried out a deep photometric survey covering about 380 arcmin^(2) in the so-called Groth Strip Flanking Fields. The observations were obtained in the KÂŽ band with the OMEGA-PRIME infrared camera at the 3.5 m telescope at the HispanoâGerman Calar Alto Observatory . Galaxy counts and photometric redshifts will be computed in order to prepare future observations with EMIR
Stellar Population Diagnostics of Elliptical Galaxy Formation
Major progress has been achieved in recent years in mapping the properties of
passively-evolving, early-type galaxies (ETG) from the local universe all the
way to redshift ~2. Here, age and metallicity estimates for local cluster and
field ETGs are reviewed as based on color-magnitude, color-sigma, and
fundamental plane relations, as well as on spectral-line indices diagnostics.
The results of applying the same tools at high redshifts are then discussed,
and their consistency with the low-redshift results is assessed. Most low- as
well as high-redshift (z~1) observations consistently indicate 1) a formation
redshift z>~3 for the bulk of stars in cluster ETGs, with their counterparts in
low-density environments being on average ~1-2 Gyr younger, i.e., formed at
z>~1.5-2, 2) the duration of the major star formation phase anticorrelates with
galaxy mass, and the oldest stellar populations are found in the most massive
galaxies. With increasing redshift there is evidence for a decrease in the
number density of ETGs, especially of the less massive ones, whereas existing
data appear to suggest that most of the most-massive ETGs were already fully
assembled at z~1. Beyond this redshift, the space density of ETGs starts
dropping significantly, and as ETGs disappear, a population of massive,
strongly clustered, starburst galaxies progressively becomes more and more
prominent, which makes them the likely progenitors to ETGs.Comment: To appear on Annual Review of Astronomy & Astrophysics, Vol. 44
(2006). 46 pages with 16 figures. Replaced version includes updated
references, few typos less, and replaces Fig. 11 and Fig. 16 which had been
skrewed u
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