208 research outputs found
A database of circumstellar OH masers
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
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
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
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-Ââuser relations with a focus on the âsecondary userâ, those who are not intended to interact directly with the technology but are intended consumers of the technologyâs 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
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A higher-resolution version of the Max Planck Institute Earth System Model (MPI-ESM1.2-HR)
The MPIâESM1.2 is the latest version of the Max Planck Institute Earth System Model and is the baseline for the Coupled Model Intercomparison Project Phase 6 and current seasonal and decadal climate predictions. This paper evaluates a coupled higherâresolution version (MPIâESM1.2âHR) in comparison with its lowerâresolved version (MPIâESM1.2âLR). We focus on basic oceanic and atmospheric mean states and selected modes of variability, the El Niño/Southern Oscillation and the North Atlantic Oscillation. The increase in atmospheric resolution in MPIâESM1.2âHR reduces the biases of upperâlevel zonal wind and atmospheric jet stream position in the northern extratropics. This results in a decrease of the storm track bias over the northern North Atlantic, for both winter and summer season. The blocking frequency over the European region is improved in summer, and North Atlantic Oscillation and related storm track variations improve in winter. Stable Atlantic meridional overturning circulations are found with magnitudes of ~16 Sv for MPIâESM1.2âHR and ~20 Sv for MPIâESM1.2âLR at 26°N. A strong sea surface temperature bias of ~5°C along with a too zonal North Atlantic current is present in both versions. The sea surface temperature bias in the eastern tropical Atlantic is reduced by ~1°C due to higherâresolved orography in MPIâESMâHR, and the region of the coldâtongue bias is reduced in the tropical Pacific. MPIâESM1.2âHR has a wellâbalanced radiation budget and its climate sensitivity is explicitly tuned to 3 K. Although the obtained reductions in longâstanding biases are modest, the improvements in atmospheric dynamics make this model well suited for prediction and impact studies
IRAS 17423-1755 (Hen 3-1475) revisited: an O-rich high-mass post-Asymptotic Giant Branch star
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
<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
Metabolische VerĂ€nderungen wĂ€hrend der Reifung von KiwifrĂŒchten (Actinidia deliciosa cv. Hayward)
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