bluuebunny/crossref_metadata_2025_split huggingface dataset:
Conceptualizing Age-Friendly Communities
Authors: Menec Verena H. , Means Robin , Keating Norah , Parkhurst Graham , Eales Jacquie 
Published: July 2011

RÉSUMÉSur le front politique et des lignes de conduite, l’intérêt a augmenté pour rendre les communautés plus « amies des ainés », cette tendance est restée constante depuis que l’Organisation mondiale de la Santé a lancé son projet « Réseau mondial des Villes-amies des aînés. » Nous conceptualisons les communautés amies des aînés en nous appuyons sur le cadre de l’OMS et l’application d’un point de vue écologique. Ainsi nous visons à rendre explicite les principales hypothèses sur l’interaction entre la personne et l’environnement afin de faire progresser la recherche ou de décisions politiques dans ce domaine. Les prémisses écologiques (par exemple, il doit y avoir une adéquation entre la personne âgée et les conditions environnementales) suggèrent la nécessité d’une approche de recherche holistique et interdisciplinaire. Une telle approche est requise car les domaines amis des aînés (l’environnement physique, le logement, l’environnement social, les possibilités de participation, le soutien communautaire formel et informel et les services de santé, de transport, de communication et de l’information) ne peuvent pas être traitées independamment des facteurs personnels, tels que l’âge, le sexe, le revenu et l’état fonctionnel, ainsi que des autres niveaux d’influence, y compris l’environnement politique.
Differential expression of Axin1, Cdc25c and Cdkn2d mRNA in 2-cell stage mouse blastomeres
Authors: Sun Jian Hong , Zhang Yong , Yin Bao Ying , Li Ji Xia , Liu Gen Sheng , Xu Wei , Tang Shuang 
Published: July 2011

SummaryThere is increasing evidence to show that 2-cell stage mouse blastomeres have differing developmental properties. Additionally, it has been suggested that such a difference might be due to their distribution of mRNA and/or protein asymmetry. However, to date, the exact genes that are involved in the orientation and order of blastomere division are not known. In this study, some differentially expressed transcripts were identified. Axin1, cell division cycle 25 homolog C (Cdc25c) and cyclin-dependent inhibitor 2D (Cdkn2d) were selected for validation by real-time polymerase chain reaction (PCR) based on published data. Our real-time PCR results demonstrated thatAxin1,Cdc25candCdkn2dgenes had different levels of expression among blastomeres of the mouse 2-cell embryo i.e. the level of Axin1 mRNA was significantly higher in one blastomere when compared with the other blastomeres of the 2-cell embryo (p< 0.05). The variation in Cdc25c (p< 0.05) and Cdkn2d (p< 0.01) mRNA expression followed a similar trend to that of Axin1. In addition, the highest levels of expression of these three genes were detected in the same blastomere in the 2-cell embryo. We confirmed that there was an asymmetrical distribution pattern for Axin1, Cdc25c and Cdkn2d transcripts in 2-cell embryos. In conclusion, this study demonstrated clearly that there is embryonic asymmetry at the 2-cell stage and that these differentially expressed genes may result in differentiation in expression in embryo development.
Testing models of rotating stars
Authors: Potter Adrian T. , Tout Christopher A. 
Published: July 2011

AbstractThe effects of rapid rotation on stellar evolution can be profound but we are only now starting to gather the data necessary to adequately determine the validity of the many proposed models of rotating stars. Some aspects of stellar rotation, particularly the treatment of angular momentum transport within convective zones, still remain very poorly explored. Distinguishing between different models is made difficult by the typically large number of free parameters in models compared with the amount of available data. This also makes it difficult to determine whether increasing the complexity of a model actually results in a better reflection of reality. We present a new code to straightforwardly compare different rotating stellar models using otherwise identical input physics. We use it to compare several models with different treatments for the transport of angular momentum within convective zones.
Results from a recent stellar rotation census of B stars
Authors: Huang Wenjin , Gies Douglas R. , McSwain M. Virginia 
Published: July 2011

AbstractIn an analysis of the rotational properties of more than 1100 B stars (~660 cluster and ~500 field B stars), we determine the projected rotational velocity (V sin i), effective temperature, gravity, mass, and critical rotation speed for each star. The new data provide us a solid observational base to explore many hot topics in this area: Why do field B stars rotate slower than cluster B stars? How fast do B stars rotate when they are just born? How fast can B stars rotate before they become Be stars? How does the rotation rate of B stars change with time? Does the evolutionary change in rotation velocity lead to the Be phenomenon? Here we report the results of our efforts in searching for answers to these questions based on the latest B star census.
Mass and angular momentum loss of fast rotating stars via decretion disks
Authors: Krtička Jiří , Owocki Stan P. , Meynet Georges 
Published: July 2011

AbstractThe spinup of massive stars induced by evolution of the stellar interior can bring the star to near-critical rotation. In critically rotating stars the decrease of the stellar moment of inertia must be balanced by a net loss of angular momentum through an equatorial decretion disk. We examine the nature and role of mass loss via such disks. In contrast to the usual stellar wind mass loss set by exterior driving from the stellar luminosity, such decretion-disk mass loss stems from the angular momentum loss needed to keep the star near and below critical rotation, given the interior evolution and decline in the star's moment of inertia. Because the specific angular momentum in a Keplerian disk increases with the square root of the radius, the decretion mass loss associated with a required level of angular momentum loss critically depends on the outer radius for viscous coupling of the disk, and can be significantly less than the spherical, wind-like mass loss commonly assumed in evolutionary calculations.
Evolutionary effects of stellar rotation of massive stars in their pre-supernova environments
Authors: Pérez-Rendón Brenda , Pineda-León Horacio , Santillán Alfredo , Hernández-Cervantes Liliana 
Published: July 2011

AbstractMassive main sequence stars are fast rotators. Stellar rotation affects massive stellar rotation due to rotationally induced mixing processes, the increase of mass loss rates, etc. and also affects the circumstellar medium due to their interaction with the stellar wind. The parameters of stellar winds depends on stellar parameters so the wind parameters change as the star evolves, coupling the evolution of circumstellar medium to the star itself. In this work we used a stellar code to build models of two massive stars (30 and 40 M⊙) and we used their wind parameters to simulate the hydrodynamics of their surrounding gas with the ZEUS-3D code in order to explore the effects of stellar rotation in the pre-supernova environments.
Modeling the winds and magnetospheres of active OB stars
Authors: Townsend Richard H. D. 
Published: July 2011

AbstractAfter briefly reviewing the theory behind the radiative line-driven winds of OB stars, I examine the processes that can generate structure in them; these include both intrinsic instabilities, and surface perturbations such as pulsation and rotation. I then delve into wind channeling and confinement by magnetic fields as a mechanism for forming longer-lived circumstellar structures. With a narrative that largely follows the historical progression of the field, I introduce the key insights and results that link the first detection of a magnetosphere, over three decades ago, to the recent direct measurement of magnetic braking in a number of active OB stars.
The constant magnetic field of ξ1 CMa: geometry or slow rotation?
Authors: Fourtune-Ravard Chloé , Wade Gregg A. , Marcolino Wagner L. F. , Shultz Matthew , Grunhut Jason H. , Henrichs Huib F. ,   the MiMeS Collaboration
Published: July 2011

AbstractWe report recent observations of the sharp-lined magnetic βCep pulsator ξ1 CMa (= HD 46328). The longitudinal magnetic field of this star is detected consistently, but it is not observed to vary significantly, during nearly 5 years of observation. In this poster we evaluate whether the constant longitudinal field is due to intrinsically slow rotation, or rather if the stellar or magnetic geometry is responsible.
Is the wind of the Oe star HD 155806 magnetically confined?
Authors: Fullerton Alex W. , Petit Véronique , Bagnulo Stefano , Wade Gregg A. ,   the MiMeS Collaboration
Published: July 2011

AbstractSpectropolarimetric observations of HD 155806 – the hottest Galactic Oe star – were obtained with CFHT/ESPaDOnS to test the hypothesis that disk signatures in its spectrum are due to magnetic channeling and confinement of its stellar wind. We did not detect a dipole field of sufficient strength to confine the wind, and could not confirm previous reports of a magnetic detection. It appears that stellar magnetism is not responsible for producing the disk of HD 155806.
Searching for magnetic fields in the descendants of massive OB stars
Authors: Grunhut Jason H. , Wade Gregg A. , Hanes David A. , Alecian Evelyne 
Published: July 2011

AbstractWe present the results of a recent survey of cool, late-type supergiants - the descendants of massive O- and B-type stars - that has systematically detected magnetic fields in these stars using spectropolarimetric observations obtained with ESPaDOnS at the Canada-France-Hawaii Telescope. Our observations reveal detectable, often complex, Stokes V Zeeman signatures in Least-Squares Deconvolved mean line profiles in a significant fraction of the observed sample of ~30 stars.
A MiMeS analysis of the magnetic field and circumstellar environment of the weak-wind O9 sub-giant star HD 57682
Authors: Grunhut Jason H. , Wade Gregg A. , Marcolino Wagner L. F. , Petit Véronique ,   the MiMeS Collaboration
Published: July 2011

AbstractI will review our recent analysis of the magnetic properties of the O9IV star HD 57682, using spectropolarimetric observations obtained with ESPaDOnS at the Canada-France-Hawaii telescope within the context of the Magnetism in Massive Stars (MiMeS) Large Program. I discuss our most recent determination of the rotational period from longitudinal magnetic field measurements and Hα variability - the latter obtained from over a decade's worth of professional and amateur spectroscopic observations. Lastly, I will report on our investigation of the magnetic field geometry and the effects of the field on the circumstellar environment.
The magnetic field of the B1/B2V star σ Lup
Authors: Henrichs Huib F. , Kolenberg Katrien , Plaggenborg Benjamin , Marsden Stephen C. , Waite Ian A. , Wade Gregg A. ,   the MiMeS collaboration
Published: July 2011

AbstractThe ultraviolet stellar wind lines of the photometrically periodic variable early B-type star σ Lupi were found to behave very similarly to what has been observed in known magnetic B stars, although no periodicity could be determined. AAT spectropolarimetric measurements with SEMPOL were obtained. We detected a longitudinal magnetic field with varying strength and amplitude of about 100 G with error bars of typically 20 G. This type of variability supports an oblique magnetic rotator model. We fold the equivalent width of the 4 usable UV spectra in phase with the well-known photometric period of 3.019 days, which we identify with the rotation period of the star. The magnetic field variations are consistent with this period. Additional observations with ESPaDOnS attached to the CFHT strongly confirmed this discovery, and allowed to determine a precise magnetic period. Like in the other magnetic B stars the wind emission likely originates in the magnetic equatorial plane, with maximum emission occurring when a magnetic pole points towards the Earth. The 3.0182 d magnetic rotation period is consistent with the photometric period, with maximum light corresponding to maximum magnetic field. No helium or other chemical peculiarity is known for this object.
Searching for weak or complex magnetic fields in polarized spectra of Rigel
Authors: Shultz Matthew , Wade Gregg A. , Neiner Coralie , Manset Nadine , Petit Véronique , Grunhut Jason H. , Guinan Edward , Hanes David A. ,   the MiMeS collaboration
Published: July 2011

AbstractSeventy-eight high-resolution Stokes V, Q and U spectra of the B8Iae supergiant Rigel were obtained with the ESPaDOnS spectropolarimeter at CFHT and its clone NARVAL at TBL in the context of the Magnetism in Massive Stars (MiMeS) Large Program, in order to scrutinize this core-collapse supernova progenitor for evidence of weak and/or complex magnetic fields. In this paper we describe the reduction and analysis of the data, the constraints obtained on any photospheric magnetic field, and the variability of photospheric and wind lines.
Influence of decoupling effect on stellar wind variability
Authors: Votruba Viktor , Šejnová Klára , Koubský Pavel , Korčáková Daniela 
Published: July 2011

AbstractA detailed investigation of momentum transfer in radiatively driven stellar winds shows that for the thin wind case ion decoupling may occur. The decoupling of absorbing ions significantly affects dynamics of the wind. We analysed such effects using our hydrodynamic code and predicted spectral changes with the help of the SHELLSPEC code.
Magnetic fields in classical Be stars: results of our long-term program with FORS1 at the VLT
Authors: Yudin Ruslan V. , Hubrig Swetlana , Pogodin Michail A. , Schoeller Markus 
Published: July 2011

AbstractWe report the results of our search for magnetic fields in a representative sample of classical Be stars carried out during 2006-2008 using low-resolution spectropolarimetry with FORS1 at the VLT. Among the 28 classical Be stars studied, detections of a magnetic field were achieved in seven stars (i.e. ~25%). The detected magnetic fields are rather weak, not stronger than ~150G. Among the Be stars studied with time series, one Be star, λ Eri, displays cyclic variability of the magnetic field with a period of 21.12 min.
ArasBeam: when amateurs contribute to Be star research
Authors: Cochard François , Desnoux Valérie , Buil Christian 
Published: July 2011

AbstractSince 2003, the amateur astronomical community has decided, in collaboration with the Paris-Meudon Observatory, to coordinate their observations to get the best spectral survey of Be stars as possible. A database for amateur and professional Be star spectra, BeSS, has been created. Spectrographs (up to R=20000) and software tools have been developed for amateurs. Among them, ArasBeam is a web-based tool designed to organize amateur Be spectral observations. A very simple color coding indicates to any observer which stars must be observed on the following night to get the best possible survey of Be stars. So far, more than 11000 amateur spectra have been collected in BeSS. About all bright Be stars (up to magnitude 8) listed in BeSS and visible from the Northern hemisphere have been observed at least one time. In addition, 6 outbursts have been detected by amateurs in the last 2 years.
Spectrographs for small telescopes
Authors: Thizy Olivier , Cochard François 
Published: July 2011

AbstractShelyak Instruments is a company founded in 2006 offering a full range of spectrographs designed for Astronomy, shipping World Wide. Current users are (1) Public and private observatories who want to setup small telescope for scientific programs or training; (2) Universities for education and demonstrations; (3) Experienced amateurs observers who work in Pro/Amateur collaborations. Lhires III Littrow high resolution spectrograph and eShel optical fibre fed echelle solution are presented with some scientific results including OB stars in which those instruments had a significant contribution.
BeSS, the official Be Star Spectra database
Authors: de Batz Bertrand , Neiner Coralie , Floquet Michèle , Cochard François 
Published: July 2011

AbstractWe present the status of the BeSS database, which contains a catalogue of all known classical Be stars and a large collection of their spectra obtained at any wavelength, any epoch, and from various sources, from amateur astronomer spectra to professional high-resolution high signal-to-noise echelle spectra. Efficient data retrieval in such a heterogeneous data collection is possible with a wide range of selection criteria thanks to their storage in the fits format and via a web interface (http://basebe.obspm.fr) as well as via the Virtual Observatory. BeSS already contains over 49000 spectra and has allowed the detection of several outbursts.
A statistical study of galactic bright Be stars
Authors: Miroshnichenko Anatoly S. 
Published: July 2011

AbstractCreation of a modern database with a wide variety of data is an important step toward a better understanding of the Be phenomenon. In an effort to do that, I refined the existing catalog of Galactic Be stars and collected available observational data for 340 brightest objects and present some results of these data analysis. New candidates for Be binaries, which seem to represent a large fraction of Be stars, are suggested. Importance of the circumstellar optical continuum for modeling of the Be star envelopes is illustrated.
The e-MERLIN Cyg OB2 radio survey (COBRaS)
Authors: Prinja Raman K. , Fenech Danielle 
Published: July 2011

AbstractThe e-MERLIN Cyg OB2 Radio Survey (COBRaS) is designed to exploit e-MERLIN's enhanced capabilities to conduct uniquely probing, targeted deep-field mapping of the massive Cyg OB2 association in our Galaxy. The project aims to deliver (between 2010 to 2013) the most detailed radio census for the most massive OB association in the northern hemisphere, offering direct comparison to not only massive clusters in general, but also young globular clusters and super star clusters. With the COBRaS Legacy project we will assemble a uniform dataset of lasting value that is critical for advancing our understanding of current astrophysical problems in the inter-related core themes of (i) mass loss and evolution of massive stars, (ii) the formation, dynamics and content of massive OB associations, and (iii) the frequency of massive binaries and the incidence of non-thermal radiation.
Spatially resolving the wind and disk structures around active B-type stars
Authors: Tycner Christopher 
Published: July 2011

AbstractLong-baseline optical and IR interferometers now routinely resolve the wind and disk-like structures around early-type stars. The typical angular scales resolved by current generation of instruments are well bellow the milli-arcsecond level. These type of observations allow, in some cases for the first time, placing very tight constraints on current theories and models of the circumstellar structures around these type of stars. Specific examples of observations obtained at the Navy Prototype Optical interferometer of the spatially resolved regions around a luminous blue variable star P Cyg and a B-type star with circumstellar disk are presented. The need for connection between interferometric observables and physical parameters predicted by theory and numerical models are emphasized.
High spatial resolution monitoring of the activity of BA supergiant winds
Authors: Chesneau Olivier , Dessart Luc , Kaufer Andreas , Mourard Denis , Stahl Otmar , Prinja Raman K. , Owocki Stan P. 
Published: July 2011

AbstractThere are currently two optical interferometry recombiners that can provide spectral resolutions better than 10000, AMBER/VLTI operating in the H-K bands, and VEGA/CHARA, recently commissioned, operating in the visible. These instruments are well suited to study the wind activity of the brightest AB supergiants in our vicinity, in lines such as Hα or Brγ. We present here the first observations of this kind, performed on Rigel (B8Ia) and Deneb (A2Ia). Rigel was monitored by AMBER in two campaigns, in 2006-2007 and 2009-2010, and observed in 2009 by VEGA; whereas Deneb was monitored in 2008-2009 by VEGA. The extension of the Hα and Brγ line forming regions were accurately measured and compared with CMFGEN models of both stars. Moreover, clear signs of activity were observed in the differential visibility and phases. These pioneer observations are still limited, but show the path for a better understanding of the spatial structure and temporal evolution of localized ejections using optical interferometry.
Analysis of the Balmer discontinuity behavior of Be stars by the Monte Carlo method
Authors: Cruzado Alicia 
Published: July 2011

AbstractFor a given photospheric model, we study the behavior of the BD as different density and temperature distributions in the circumstellar envelope are assumed. For non spherically symmetric envelopes, we analyze the variation of the BD when the angle of observation varies. The radiation transfer through the medium is handled by means of the Monte Carlo method. We calculate the flux emitted by the star+envelope system in a small wavelength range around the BD. The calculations are made under LTE conditions.
Infrared continuum sizes of Be star disks
Authors: Gies Douglas R. , Touhami Yamina N. , Schaefer Gail H. 
Published: July 2011

AbstractLong baseline interferometry now offers us the opportunity to measure the dimensions of Be star circumstellar disks across the spectrum. This includes the near-infrared continuum where the emission is dominated by bound-free and free-free emission from the ionized disk gas. Here we present the results of calculations of the disk sizes and continuum flux excesses for a simple version of the viscous decretion model of the disk. We compare these results to recent 18 μm flux measurements from the AKARI infrared satellite all-sky survey.
K- and L-band spectroscopy of Be stars
Authors: Granada Anahí , Arias María L. , Cidale Lydia S. , Mennickent Ronald E. 
Published: July 2011

AbstractWe describe the behaviour of IR hydrogen emission lines of a sample of Be stars and discuss the physical properties of the circumstellar envelopes of Be stars classified in Groups I and II (Mennickent et al. 2009). We find that while Humphreys and Pfund lines of Group I stars form in an optically thick envelope/disk, Group II stars show Pfund lines that form in an optically thick medium and Humphreys lines originating in optically thinner regions. The transition between Groups I and II could be understood in terms of the evolution of the circumstellar disk of the star and might bring clues on the mechanism originating the Be phenomenon.
The inhomogeneous wind of the LBV candidate Cyg OB2 No.12
Authors: Klochkova Valentina G. , Chentsov Eugene L. , Miroshnichenko Anatoly S. 
Published: July 2011

AbstractWe present the results of high-resolution spectroscopy of the extremely luminous star Cyg OB2 No. 12. We identified about 200 spectral features in the range 4552–7939 Å, including the interstellar Na I, K I lines and numerous very strong DIBs, along with the He I, C II, and Si II lines. An MK spectral type we derived for the object is B4.5±0.5 Ia+. Our analysis of the radial velocity data shows the presence of a gradient in the stellar atmosphere, caused by both atmospheric expansion and matter infall onto the star. The Hα emission displays broad Thompson wings, a slightly blue-shifted P Cyg type absorption component and a time-variable core absorption. We conclude that the wind is variable in time.