197 research outputs found
The Magellanic zoo: Mid-infrared Spitzer spectroscopy of evolved stars and circumstellar dust in the Magellanic Clouds
We observed a sample of evolved stars in the Large and Small Magellanic
Clouds (LMC and SMC) with the Infrared Spectrograph on the Spitzer Space
Telescope. Comparing samples from the SMC, LMC, and the Galaxy reveals that the
dust-production rate depends on metallicity for oxygen-rich stars, but carbon
stars with similar pulsation properties produce similar quantities of dust,
regardless of their initial metallicity. Other properties of the oxygen-rich
stars also depend on metallicity. As the metallicity decreases, the fraction of
naked (i.e. dust-free) stars increases, and among the naked stars, the strength
of the 8 um absorption band from SiO decreases. Our sample includes several
massive stars in the LMC with long pulsation periods which produce significant
amounts of dust, probably because they are young and relatively metal rich.
Little alumina dust is seen in circumstellar shells in the SMC and LMC, unlike
in Galactic samples. Three oxygen-rich sources also show emission from
magnesium-rich crystalline silicates. Many also show an emission feature at 14
um. The one S star in our sample shows a newly detected emission feature
centered at 13.5 um. At lower metallicity, carbon stars with similar amounts of
amorphous carbon in their shells have stronger absorption from molecular
acetylene (C_2H_2) and weaker emission from SiC and MgS dust, as discovered in
previous studies.Comment: ApJ, in press, about 27 pages, 29 figure
Quantitation of Human Seroresponsiveness to Merkel Cell Polyomavirus
Merkel cell carcinoma (MCC) is a relatively uncommon but highly lethal form of skin cancer. A majority of MCC tumors carry DNA sequences derived from a newly identified virus called Merkel cell polyomavirus (MCV or MCPyV), a candidate etiologic agent underlying the development of MCC. To further investigate the role of MCV infection in the development of MCC, we developed a reporter vector-based neutralization assay to quantitate MCV-specific serum antibody responses in human subjects. Our results showed that 21 MCC patients whose tumors harbored MCV DNA all displayed vigorous MCV-specific antibody responses. Although 88% (42/48) of adult subjects without MCC were MCV seropositive, the geometric mean titer of the control group was 59-fold lower than the MCC patient group (p<0.0001). Only 4% (2/48) of control subjects displayed neutralizing titers greater than the mean titer of the MCV-positive MCC patient population. MCC tumors were found not to express detectable amounts of MCV VP1 capsid protein, suggesting that the strong humoral responses observed in MCC patients were primed by an unusually immunogenic MCV infection, and not by viral antigen expressed by the MCC tumor itself. The occurrence of highly immunogenic MCV infection in MCC patients is unlikely to reflect a failure to control polyomavirus infections in general, as seroreactivity to BK polyomavirus was similar among MCC patients and control subjects. The results support the concept that MCV infection is a causative factor in the development of most cases of MCC. Although MCC tumorigenesis can evidently proceed in the face of effective MCV-specific antibody responses, a small pilot animal immunization study revealed that a candidate vaccine based on MCV virus-like particles (VLPs) elicits antibody responses that robustly neutralize MCV reporter vectors in vitro. This suggests that a VLP-based vaccine could be effective for preventing the initial establishment of MCV infection
Downward Wage Rigidity for Different Workers and Firms: An Evaluation for Belgium Using the IWFP Procedure
This paper evaluates the extent of downward nominal and real wage rigidity for different categories of workers and firms using the methodology recently developed by the International Wage Flexibility Project (Dickens and Goette, 2006). The analysis is based on an administrative data set on individual earnings, covering one-third of employees of the private sector in Belgium over the period 1990-2002. Our results show that Belgium is characterised by strong real wage rigidity and very low nominal wage rigidity, consistent with the Belgian wage formation system of full indexation. Real rigidity is stronger for white-collar workers than for blue-collar workers. Real rigidity decreases with age and wage level. Wage rigidity appears to be lower in firms experiencing downturns. Finally, smaller firms and firms with lower job quit rates appear to have more rigid wages. Our results are robust to alternative measures of rigidit
Technology Transfers and the Clean Development Mechanism in a North-South General Equilibrium Model
This paper analyzes the potential welfare gains of introducing a technology transfer from Annex I to non-Annex I in order to mitigate greenhouse gas emissions. Our analysis is based on a numerical general equilibrium model for a world economy comprising two regions, North (Annex I) and South (non-Annex I). As our model allows for labor mobility between the formal and informal sectors in the South, we are also able to capture additional aspects of how the transfer influences the Southern economy. In a cooperative equilibrium, a technology transfer from the North to the South is clearly desirable from the perspective of a global social planner, since the welfare gain for the South outweighs the welfare loss for the North. However, if the regions do not cooperate, then the incentives to introduce the technology transfer appear to be relatively weak from the perspective of the North; at least if we allow for Southern abatement in the pre-transfer Nash equilibrium. Finally, by adding the emission reductions associated with the Kyoto agreement to an otherwise uncontrolled market economy, the technology transfer leads to higher welfare in both regions
Signal transduction underlying the control of urinary bladder smooth muscle tone by muscarinic receptors and β-adrenoceptors
The normal physiological contraction of the urinary bladder, which is required for voiding, is predominantly mediated by muscarinic receptors, primarily the M3 subtype, with the M2 subtype providing a secondary backup role. Bladder relaxation, which is required for urine storage, is mediated by β-adrenoceptors, in most species involving a strong β3-component. An excessive stimulation of contraction or a reduced relaxation of the detrusor smooth muscle during the storage phase of the micturition cycle may contribute to bladder dysfunction known as the overactive bladder. Therefore, interference with the signal transduction of these receptors may be a viable approach to develop drugs for the treatment of overactive bladder. The prototypical signaling pathway of M3 receptors is activation of phospholipase C (PLC), and this pathway is also activated in the bladder. Nevertheless, PLC apparently contributes only in a very minor way to bladder contraction. Rather, muscarinic-receptor-mediated bladder contraction involves voltage-operated Ca2+ channels and Rho kinase. The prototypical signaling pathway of β-adrenoceptors is an activation of adenylyl cyclase with the subsequent formation of cAMP. Nevertheless, cAMP apparently contributes in a minor way only to β-adrenoceptor-mediated bladder relaxation. BKCa channels may play a greater role in β-adrenoceptor-mediated bladder relaxation. We conclude that apart from muscarinic receptor antagonists and β-adrenoceptor agonists, inhibitors of Rho kinase and activators of BKCa channels may have potential to treat an overactive bladder
CURATION AND MANAGEMENT OF CULTURAL HERITAGE THROUGH LIBRARIES
Libraries, museums and archives hold valuable collections in a variety of media, presenting a vast
body of knowledge rooted in the history of human civilisation. These form the repository of the
wisdom of great works by thinkers of past and the present. The holdings of these institutions are
priceless heritage of the mankind as they preserve documents, ideas, and the oral and written
records. To value the cultural heritage and to care for it as a treasure bequeathed to us by our
ancestors is the major responsibility of libraries. The past records constitute a natural resource
and are indispensable to the present generation as well as to the generations to come. Libraries
preserve the documentary heritage resources for which they are primarily responsible. Any loss of
such materials is simply irreplaceable. Therefore, preserving this intellectual, cultural heritage
becomes not only the academic commitment but also the moral responsibility of the
librarians/information scientists, who are in charge of these repositories.
The high quality of the papers and the discussion represent the thinking and experience of experts
in their particular fields. The contributed papers also relate to the methodology used in libraries
in Asia to provide access to manuscripts and cultural heritage. The volume discusses best practices
in Knowledge preservation and how to collaborate and preserve the culture. The book also deals with
manuscript and archives issues in the digital era.
The approach of this book is concise, comprehensively, covering all major aspects of preservation
and conservation through libraries. The readership of the book is not just limited to library and
information science professionals, but also for those involved in conservation, preservation,
restoration or other related disciplines. The book will be useful for librarians, archivists and
conservators.
We thank the Sunan Kalijaga University, Special Libraries Association- Asian Chapter for their
trust and their constant support, all the contributors for their submissions, the members of the Local
and International Committee for their reviewing effort for making this publication possible
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