208 research outputs found

    A database of circumstellar OH masers

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    We present a new database of circumstellar OH masers at 1612, 1665, and 1667 MHz in the Milky Way galaxy. The database (version 2.4) contains 13655 observations and 2341 different stars detected in at least one transition. Detections at 1612\,MHz are considered to be complete until the end of 2014 as long as they were published in refereed papers. Detections of the main lines (1665 and 1667 MHz) and non-detections in all transitions are included only if published after 1983. The database contains flux densities and velocities of the two strongest maser peaks, the expansion velocity of the shell, and the radial velocity of the star. Links are provided for about 100 stars (<<5\% of all stars with OH masers) to interferometric observations and monitoring programs of the maser emission published since their beginnings in the 1970s. Access to the database is possible over the Web (www.hs.uni-hamburg.de/maserdb), allowing cone searches for individual sources and lists of sources. A general search is possible in selected regions of the sky and by defining ranges of flux densities and/or velocities. Alternative ways to access the data are via the German Virtual Observatory and the VizieR library of astronomical catalogs.Comment: 9 pages, 7 figures, accepted for publication in Astronomy & Astrophysics. Replaced because of faulty compilation of the pdf fil

    Disciplining customers at the Grand Seaside Hotel

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    The Grand Seaside Hotel is a large five-star hotel in an Australian Coastal town. It is a place that not only aspires to provide excellent service but that also seeks to reconcile two apparently divergent demands: the need for customized service and the efficient management of business operations. To commit staff to the provision of service excellence, management has introduced a customer service programme that relies on various forms of training and rewards, as well as a guest response system. The customer service programme, particularly the use of guest questionnaires, appear as disciplinary strategies that aim to produce service encounters in which both staff and guests are 'normalized'. The main loci of ethnographic data collection for this paper are regular Management Briefings. Through data collected from these, the paper investigates the use of the 'imaginary' in constituting service encounters and guest expectations. It interprets these in terms of Foucault's Panoptic analysis to identify the immanent mechanisms of discipline in these customer service programmes

    Heavy Element Nucleosynthesis in the Brightest Galactic Asymptotic Giant Branch stars

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    We present updated calculations of stellar evolutionary sequences and detailed nucleosynthesis predictions for the brightest asymptotic giant branch (AGB) stars in the Galaxy with masses between 5Msun to 9Msun, with an initial metallicity of Z =0.02 ([Fe/H] = 0.14). In our previous studies we used the Vassiliadis & Wood mass-loss rate, which stays low until the pulsation period reaches 500 days after which point a superwind begins. Vassiliadis & Wood noted that for stars over 2.5Msun the superwind should be delayed until P ~ 750 days at 5Msun. We calculate evolutionary sequences where we delay the onset of the superwind to pulsation periods of P ~ 700-800 days in models of M = 5, 6, and 7Msun. Post-processing nucleosynthesis calculations show that the 6 and 7Msun models produce the most Rb, with [Rb/Fe] ~ 1 dex, close to the average of most of the Galactic Rb-rich stars ([Rb/Fe] ~ 1.4 plus or minus 0.8 dex). Changing the rate of the 22Ne + alpha reactions results in variations of [Rb/Fe] as large as 0.5 dex in models with a delayed superwind. The largest enrichment in heavy elements is found for models that adopt the NACRE rate of the 22Ne(a,n)25Mg reaction. Using this rate allows us to best match the composition of most of the Rb-rich stars. A synthetic evolution algorithm is then used to remove the remaining envelope resulting in final [Rb/Fe] of ~ 1.4 dex although with C/O ratios > 1. We conclude that delaying the superwind may account for the large Rb overabundances observed in the brightest metal-rich AGB stars.Comment: 37 pages, accepted for publication in the Astrophysical Journal, minor modifications to text and Tables 2 and 3, reference adde

    Secondary user relations in emerging mobile computing environments

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    Mobile technologies are enabling access to information in diverse environ.ments, and are exposing a wider group of individuals to said technology. Therefore, this paper proposes that a wider view of user relations than is usually considered in information systems research is required. Specifically, we examine the potential effects of emerging mobile technologies on end-­‐user relations with a focus on the ‘secondary user’, those who are not intended to interact directly with the technology but are intended consumers of the technology’s output. For illustration, we draw on a study of a U.K. regional Fire and Rescue Service and deconstruct mobile technology use at Fire Service incidents. Our findings provide insights, which suggest that, because of the nature of mobile technologies and their context of use, secondary user relations in such emerging mobile environments are important and need further exploration

    IRAS 17423-1755 (Hen 3-1475) revisited: an O-rich high-mass post-Asymptotic Giant Branch star

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    The high-resolution (R=600) Spitzer/IRS spectrum of the bipolar proto-planetary nebula (PPN) IRAS 17423-1755 is presented in order to clarify the dominant chemistry (C-rich versus O-rich) of its circumstellar envelope as well as to constrain its evolutionary stage. The high quality Spitzer/IRS spectrum shows weak 9.7 um absorption from amorphous silicates. This confirms for the first time the O-rich nature of IRAS 17423-1755 in contradiction to a previous C-rich classification, which was based on the wrong identification of the strong 3.1 um absorption feature seen in the Infrared Space Observatory (ISO) spectrum as due to acetylene (C2H2). The high-resolution Spitzer/IRS spectrum displays a complete lack of C-rich mid-IR features such as molecular absorption features (e.g., 13.7 um C2H2, 14.0 um HCN, etc.) or the classical polycyclic aromatic hydrocarbon infrared emission bands. Thus, the strong 3.1 um absorption band toward IRAS 17423-1755 has to be identified as water ice. In addition, a [Ne II] nebular emission line at 12.8 um is clearly detected, indicating that the ionization of its central region may be already started. The spectral energy distribution in the infrared (2-200 um) and other observational properties of IRAS 17423-1755 are discussed in comparison with the similar post-asymptotic giant branch (AGB) objects IRAS 19343+2926 and IRAS 17393-2727. We conclude that IRAS 17423-1755 is an O-rich high-mass post-AGB object that represents a link between OH/IR stars with extreme outflows and highly bipolar PN.Comment: accepted for publication in The Astronomical Journal (19 pages and 5 figures

    An extensive phenotypic characterization of the hTNFα transgenic mice

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    <p>Abstract</p> <p>Background</p> <p>Tumor necrosis factor alpha (TNFα) is implicated in a wide variety of pathological and physiological processes, including chronic inflammatory conditions, coronary artery disease, diabetes, obesity, and cachexia. Transgenic mice expressing human TNFα (hTNFα) have previously been described as a model for progressive rheumatoid arthritis. In this report, we describe extensive characterization of an hTNFα transgenic mouse line.</p> <p>Results</p> <p>In addition to arthritis, these hTNFα transgenic mice demonstrated major alterations in body composition, metabolic rate, leptin levels, response to a high-fat diet, bone mineral density and content, impaired fertility and male sexual function. Many phenotypes displayed an earlier onset and a higher degree of severity in males, pointing towards a significant degree of sexual dimorphism in response to deregulated expression of TNFα.</p> <p>Conclusion</p> <p>These results highlight the potential usefulness of this transgenic model as a resource for studying the progressive effects of constitutively expressed low levels of circulating TNFα, a condition mimicking that observed in a number of human pathological conditions.</p
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