612 research outputs found
The Onfp Class in the Magellanic Clouds
The Onfp class of rotationally broadened, hot spectra was defined some time
ago in the Galaxy, where its membership to date numbers only eight. The
principal defining characteristic is a broad, centrally reversed He II
4686 emission profile; other emission and absorption lines are also
rotationally broadened. Recent surveys in the Magellanic Clouds (MCs) have
brought the class membership there, including some related spectra, to 28. We
present a survey of the spectral morphology and rotational velocities, as a
first step toward elucidating the nature of this class. Evolved, rapidly
rotating hot stars are not expected theoretically, because the stellar winds
should brake the rotation. Luminosity classification of these spectra is not
possible, because the principal criterion (He II 4686) is peculiar;
however, the MCs provide reliable absolute magnitudes, which show that they
span the entire range from dwarfs to supergiants. The Onfp line-broadening
distribution is distinct and shifted toward larger values from those of normal
O dwarfs and supergiants with >99.99% confidence. All cases with multiple
observations show line-profile variations, which even remove some objects from
the class temporarily. Some of them are spectroscopic binaries; it is possible
that the peculiar profiles may have multiple causes among different objects.
The origin and future of these stars are intriguing; for instance, they could
be stellar mergers and/or gamma-ray-burst progenitors.Comment: 27 pages, 8 figures, 2 tables; AJ accepte
A Survey of Local Group Galaxies Currently Forming Stars. I. UBVRI Photometry of Stars in M31 and M33
We present UBVRI photometry obtained from Mosaic images of M31 and M33 using
the KPNO 4-m telescope. The survey covers 2.2 sq degrees of M31, and 0.8 sq
degrees of M33, chosen so as to include all of the regions currently active in
forming massive stars. The catalog contains 371,781 and 146,622 stars in M31
and M33, respectively, where every star has a counterpart (at least) in B, V,
and R. We compare our photometry to previous studies. We provide cross
references to the stars confirmed as members by spectroscopy, and compare the
location of these to the complete set in color-magnitude diagrams. While
follow-up spectroscopy is needed for many projects, we demonstrate the success
of our photometry in being able to distinguish M31/M33 members from foreground
Galactic stars. We also present the results of newly obtained spectroscopy,
which identifies 34 newly confirmed members, including B-A supergiants, the
earliest O star known in M31, and two new Luminous Blue Variable candidates
whose spectra are similar to that of P Cygni.Comment: Accepted by the Astronomical Journal. A version with higher
resolution figures can be found at:
http://www.lowell.edu/users/massey/M3133.pdf.g
A Catalog of Transient X-ray Sources in M31
From October 1999 to August 2002, 45 transient X-ray sources were detected in
M31 by Chandra and XMM-Newton. We have performed spectral analysis of all
XMM-Newton and Chandra ACIS detections of these sources, as well as flux
measurements of Chandra HRC detections. The result is absorption-corrected
X-ray lightcurves for these sources covering this 2.8 year period, along with
spectral parameters for several epochs of the outbursts of most of the
transient sources. We supply a catalog of the locations, outburst dates, peak
observed luminosities, decay time estimates, and spectral properties of the
transient sources, and we discuss similarities with Galactic X-ray novae. Duty
cycle estimates are possible for 8 of the transients and range from 40% to 2%;
upper limits to the duty cycles are estimated for an additional 15 transients
and cover a similar range. We find 5 transients which have rapid decay times
and may be ultra-compact X-ray binaries. Spectra of three of the transients
suggest they may be faint Galactic foreground sources. If even one is a
foreground source, this suggests a surface density of faint transient X-ray
sources of >~1 deg.Comment: 63 pages, 22 figures, 3 tables, accepted for publication in Ap
“It’s like my life but more, and better!” - Playing with the Cathaby Shark Girls: MMORPGs, young people and fantasy-based social play
This article is available open access through the publisher’s website at the link below. Copyright @ 2011 A B Academic Publishers.Digital technology has opened up a range of new on-line leisure spaces for young people. Despite their popularity, on-line games and Massive Multiplayer Online Role Playing Games in particular are still a comparatively under-researched area in the fields of both Education and more broadly Youth Studies. Drawing on a Five year ethnographic study, this paper considers the ways that young people use the virtual spaces offered by MMORPGs. This paper suggests that MMORPGs represent significant arenas within which young people act out a range of social narratives through gaming. It argues that MMORPG have become important fantasy spaces which offer young people possibilities to engage in what were formally material practices. Although this form of play is grounded in the everyday it also extends material practices and offers new and unique forms of symbolic experimentation, thus I argue that game-play narratives cannot be divorced from the everyday lives of their participants
The structural invisibility of outsiders: the role of migrant labour in the meat-processing industry
This article examines the role of migrant workers in meat-processing factories in the UK. Drawing on materials from mixed methods research in a number of case study towns across Wales, we explore the structural and spatial processes that position migrant workers as outsiders. While state policy and immigration controls are often presented as a way of protecting migrant workers from work-based exploitation and ensuring jobs for British workers, our research highlights that the situation ‘on the ground’ is more complex. We argue that ‘self-exploitation’ among the migrant workforce is linked to the strategies of employers and the organisation of work, and that hyper-flexible work patterns have reinforced the spatial and social invisibilities of migrant workers in this sector. While this creates problems for migrant workers, we conclude that it is beneficial to supermarkets looking to supply consumers with the regular supply of cheap food to which they have become accustomed
An examination of business occupier relocation decision making : distinguishing small and large firm behaviour
This paper explores how business occupiers decide whether and where to relocate. It captures the experience and behaviour of a range of sizes and types of business occupier and subjects their decision-making processes to detailed scrutiny. A linear three-stage decision model is used to sequence and structure interviews with individuals who have intimate involvement with the relocation of 28 firms and organizations in Tyne and Wear, in the north-east of England. The 'constant comparative' method is used to analyse the interview data, from which emerges 18 key concepts, comprising 51 characteristic components. Using an axial approach, these are organized into 10 cross-cutting themes that represent the main areas of consideration or influence on the thinking of the people involved in determining whether a firm or organization should relocate and, if so, where to. The resulting analysis finds that organizations adopt varying degrees of sophistication when making relocation decisions; small firms are more inclined to make decisions based on constrained information; larger organizations adopt a more complex approach. Regardless of firm size, key individuals exert considerable influence over the decision-making process and its outcome
A Survey of Local Group Galaxies Currently Forming Stars: III. A Search for Luminous Blue Variables and Other H-alpha Emission-Lined Stars
We describe a search for H-alpha emission-lined stars in M31, M33, and seven
dwarfs in or near the Local Group (IC 10, NGC 6822, WLM, Sextans B, Sextans A,
Pegasus and the Phoenix dwarf) using interference filter imaging with the KPNO
and CTIO 4-m telescope and Mosaic cameras. The survey is aimed primarily at
identifying new Luminous Blue Variables (LBVs) from their spectroscopic
similarity to known LBVs, avoiding the bias towards photometric variability,
which may require centuries to manifest itself if LBVs go through long
quiescent periods. Followup spectroscopy with WIYN confirms that our survey
detected a wealth of stars whose spectra are similar to the known LBVs. We
"classify" the spectra of known LBVs, and compare these to the spectra of the
new LBV candidates. We demonstrate spectacular spectral variability for several
of the new LBV candidates, such as AM2, previously classified as a Wolf-Rayet
star, which now shows FeI, FeII and Balmer emission lines but neither the NIII
4634,42 nor HeII 4686 emission that it did in 1982. Profound spectral changes
are also noted for other suspected and known LBVs. Several of the LBV
candidates also show >0.5 mag changes in V over the past 10-20 years. The
number of known or suspected LBVs is now 24 in M31, 37 in M33, 1 in NGC 6822,
and 3 in IC 10. We estimate that the total number of LBVs in M31 and M33 may be
several hundred, in contrast to the 8 known historically through large-scale
photometric variability. This has significant implications for the time scale
of the LBV phase. We also identify a few new WRs and peculiar emission-lined
objects.Comment: Accepted by the Astronomical Journal. Version with higher quality
figures may be downloaded from http://www.lowell.edu/users/massey/has.pdf.g
Marketing to different Asian communities The importance of culture for framing advertising messages, and for purchase intent
Abstract Purpose -The purpose of this paper is to show that culture has differential effects on purchase intent, using respondents from four very different cultural groups within Indonesia, and two different advertisements (one ethical, another unethical). Design/methodology/approach -The study uses survey methods and a highly structured questionnaire to collect data from respondents in four cultural groups. In total, 100 responses were received from each of these groups within Indonesia (Bali, Batak, Java, and Minang). Data were analyzed using partial least squares. Findings -The results suggest that when advertising to culturally conservative groups, caution is required. Such groups have lower purchase intent when they do not like the advertisement. Moreover, other variables such as attitude towards the advertiser may become salient drivers of purchase intent for such groups if the advertisement is perceived to be unethical. Importantly, neither of these factors are salient for more permissive cultures, regardless of whether the advertisement is perceived to be ethical or unethical. In addition the authors identify a set of "universal paths" by which advertisement-related factors, and company-related factors indirectly influence purchase intent for both permissive and conservative cultures, regardless of the perceived ethicality of the advertisement. Research limitations/implications -The research uses four samples, with 100 respondents per group. Future research could verify these results using larger samples. In addition, the study only uses low involvement consumer products, hence future research could test the model on higher involvement products. Practical implications -Managers should test their advertising messages on target audiences to assess whether they are likeable, as advertisement likeability can influence purchase intent. In addition, whilst factors such as ethicality (and likeability, and attitude towards the advertiser) tend to not affect purchase intent directly except in specific circumstances, these antecedent variables do have strong effects on each other via the universal paths. Originality/value -This is the first study which has examined the effects of ethical/unethical advertisements across four different cultures in Indonesia. The results also reveal an important set of relationships between the model variables, which the authors refer to as the "universal paths." These paths have important implications for advertisers and their clients in their attempts to build brand equity and increase purchase intent
IKK phosphorylates Huntingtin and targets it for degradation by the proteasome and lysosome
Expansion of the polyglutamine repeat within the protein Huntingtin (Htt) causes Huntington's disease, a neurodegenerative disease associated with aging and the accumulation of mutant Htt in diseased neurons. Understanding the mechanisms that influence Htt cellular degradation may target treatments designed to activate mutant Htt clearance pathways. We find that Htt is phosphorylated by the inflammatory kinase IKK, enhancing its normal clearance by the proteasome and lysosome. Phosphorylation of Htt regulates additional post-translational modifications, including Htt ubiquitination, SUMOylation, and acetylation, and increases Htt nuclear localization, cleavage, and clearance mediated by lysosomal-associated membrane protein 2A and Hsc70. We propose that IKK activates mutant Htt clearance until an age-related loss of proteasome/lysosome function promotes accumulation of toxic post-translationally modified mutant Htt. Thus, IKK activation may modulate mutant Htt neurotoxicity depending on the cell's ability to degrade the modified species
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