5,712 research outputs found
Carbon star survey in the Local Group. VII. NGC 3109 a galaxy without a stellar halo
We present a CFH12K wide field survey of the carbon star population in and
around NGC 3109. Carbon stars, the brightest members of the intermediate-age
population, were found nearly exclusively in and near the disk of NGC 3109,
ruling out the existence of an extensive intermediate-age halo like the one
found in NGC 6822. Over 400 carbon stars identified have = -4.71,
confirming the nearly universality of mean magnitude of C star populations in
Local Group galaxies. Star counts over the field reveal that NGC 3109 is a
truncated disk shaped galaxy without an extensive stellar halo. The minor axis
star counts reach the foreground density between 4' and 5', a distance that can
be explained by an inclined disk rather than a spheroidal halo. We calculate a
global C/M ratio of 1.75 +/- 0.20, a value expected for such a metal poor
galaxy.Comment: Accepted in Astronomy and Astrophysic
Extension of the C star rotation curve of the Milky Way to 24 kpc
Demers and Battinelli published, in 2007 the rotation curve of the Milky Way
based on the radial velocity of carbon stars outside the Solar circle. Since
then we have established a new list of candidates for spectroscopy. The goal of
this paper is to determine the rotation curve of the galaxy, as far as possible
from the galactic center, using N type carbon stars. The stars were selected
from their dereddened 2MASS colours, then the spectra were obtained with the
Dominion Astrophysical Observatory and Asiago 1.8 meter telescopes. This
publication adds radial velocities and Galactrocentric distances of 36 carbon
stars, from which 20 are new confirmed. The new results for stars up to 25 kpc
from the galactic center, suggest that the rotation curve shows a slight
decline beyond the Solar circle.Comment: 13 pages, 3 figures, 1 table; accepted for publication in
Astrophysic
C stars in the outer spheroid of NGC 6822
From a 2 x 2 degree survey of NGC 6822 we have previously established that
this Local Group dwarf irregular galaxy possesses a huge spheroid having more
than one degree in length. This spheroid is in rotation but its rotation curve
is known only within ~15' from the center. It is therefore critical to identify
bright stars belonging to the spheroid to characterize, as far as possible, its
outer kinematics. We use the new wide field near infrared imager CPAPIR,
operated by the SMARTS consortium, to acquire J, Ks images of two 34.8' x 34.8'
areas in the outer spheroid to search for C stars. The colour diagram of the
fields allows the identification of 192 C stars candidates but a study of the
FWHM of the images permits the rejection of numerous non-stellar objects with
colours similar to C stars. We are left with 75 new C stars, their mean Ks
magnitude and mean colour are similar to the bulk of known NGC 6822 C stars.
This outer spheroid survey confirms that the intermediate-age AGB stars are a
major contributor to the stellar populations of the spheroid. The discovery of
some 50 C stars well beyond the limit of the previously known rotation curve
calls for a promising spectroscopic follow-up to a major axis distance of 40'.Comment: 13 page
Behavior of the Escape Rate Function in Hyperbolic Dynamical Systems
For a fixed initial reference measure, we study the dependence of the escape
rate on the hole for a smooth or piecewise smooth hyperbolic map. First, we
prove the existence and Holder continuity of the escape rate for systems with
small holes admitting Young towers. Then we consider general holes for Anosov
diffeomorphisms, without size or Markovian restrictions. We prove bounds on the
upper and lower escape rates using the notion of pressure on the survivor set
and show that a variational principle holds under generic conditions. However,
we also show that the escape rate function forms a devil's staircase with jumps
along sequences of regular holes and present examples to elucidate some of the
difficulties involved in formulating a general theory.Comment: 21 pages. v2 differs from v1 only by additions to the acknowledgment
Child Massage Integrated Therapy: A Preliminary Intervention Manual for Psychological Trauma Treatment
This dissertation introduces an original preliminary treatment manual as a guide for mental health providers interested in adding a research-informed massage therapy component to traditional child trauma psychotherapy.Child Massage Integrated Therapy (CMIT) offers a standardized protocol to support the implementation of a replicable treatment modality that fosters critical somatic resources for traumatized children within real-world settings. The multidisciplinary field of interpersonal neurobiology, including attachment and polyvagal theories, as well as the concept of interoceptive awareness, are the theoretical constructs informing the proposed model of care. A review of the research literature recognizing massage therapy\u27s role in creating a regulating mind/body experience provides the fundamental basis for pursuing this line of intervention as a component of a phase-oriented psychological trauma treatment
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The moral microfoundations of institutional complexity: Sustainability implementation as compromise-making at an oil sands company
Research on institutional complexity has overlooked the fact that moral judgements are likely involved when individuals face a plurality of logics within organizations. To analyze the moral microfoundations of institutional complexity, we build on Boltanski and Thévenot’s (2006 [1991]) economies of worth (EW) framework and explore how individuals produce moral judgement in response to the institutional complexity triggered by a major shift in the sustainability strategy within an oil sands company. Fifty-two interviews with employees, managers and executives reveal how actors rely on four types of justification that combine different moral principles and related objects with the aim of either forming (sheltering and solidifying work) or challenging (fragilizing and deconstructing work) a new compromise with regard to sustainability within the organization. Our results show how the EW framework can enrich institutional complexity theory by bringing morality back into the analysis as a core dimension of inhabited institutions while advancing the microanalysis of compromise-making around sustainability in organization studies
A family of pseudo-Anosov maps
We study a family of area-preserving maps of the 2-torus and show that they are pseudo-Anosov. We present a method to construct finite Markov partitions for this family which utilizes their common symmetries. Through these partitions we show explicitly that each map is a tower over a first return map, intimately linked to a toral automorphism. This enables us to calculate directly some dimensional characteristics of the dynamics
USE OF INHALANT ANESTHETICS IN THREE SNAKE SPECIES
Different snake species respond differently to various anesthetic agents. Hence, an anesthetic procedure developed for one species cannot necessarily be safely transferred to another species. The goal of this paper is to summarize our experience using inhalant anesthetics on three snake species, including both procedures that were successful and those we found to be less satisfactory. We found isoflurane delivered with a precision vaporizer to be the best agent to anesthetize black rat snakes (Elaphe o. obsoleta). Sex and mass did not seem to affect induction times in black rat snakes, but larger female rat snakes recovered faster from anesthesia than smaller females. Halothane delivered in the open method provided consistent anesthesia in northern water snakes (Nerodia s. sipedon), although it caused some mortality and should not be used on debilitated patients. Halothane delivered with a precision vaporizer may be used to anesthetize eastern massasauga rattlesnakes (Sistrurus c. catenatus). However, care must be taken to prevent mortality resulting from anesthetic overdose. Sex and mass had no effect on induction and recovery times in the rattlesnakes, but stressed animals require longer induction and recovery times
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