868 research outputs found
The close circumstellar environment of the semi-regular S-type star Pi^1 Gruis
We study the close circumstellar environment of the nearby S-type star Pi^1
Gruis using high spatial-resolution, mid-infrared observations from the
ESO/VLTI. Spectra and visibilities were obtained with the MIDI interferometer
on the VLT Auxiliary Telescopes. The cool M5III giant Beta Gruis was used as
bright primary calibrator, and a dedicated spectro-interferometric study was
undertaken to determine its angular diameter accurately. The MIDI measurements
were fitted with the 1D numerical radiative transfer code DUSTY to determine
the dust shell parameters of Pi^1 Gruis. Taking into account the low spatial
extension of the model in the 8-9 m spectral band for the smallest
projected baselines, we consider the possibility of a supplementary molecular
shell. The MIDI visibility and phase data are mostly dominated by the spherical
21 mas (694 Rsol) central star, while the extended dusty environment is
over-resolved even with the shortest baselines. No obvious departure from
spherical symmetry is found on the milliarcsecond scale. The
spectro-interferometric observations are well-fitted by an optically thin
(tau(dust)<0.01 in the band) dust shell that is located at about 14 stellar
radii with a typical temperature of 700 K and composed of 70% silicate and 30%
of amorphous alumina grains. An optically thin (tau(mol)<0.1 in the N band)
H2O+SiO molecular shell extending from the photosphere of the star up to 4.4
stellar radii with a typical temperature of 1000 K is added to the model to
improve the fit in the 8-9 m spectral band. We discuss the probable binary
origin of asymmetries as revealed by millimetric observations
Selecting information technology for physicians' practices: a cross-sectional study
BACKGROUND: Many physicians are transitioning from paper to electronic formats for billing, scheduling, medical charts, communications, etc. The primary objective of this research was to identify the relationship (if any) between the software selection process and the office staff's perceptions of the software's impact on practice activities. METHODS: A telephone survey was conducted with office representatives of 407 physician practices in Oregon who had purchased information technology. The respondents, usually office managers, answered scripted questions about their selection process and their perceptions of the software after implementation. RESULTS: Multiple logistic regression revealed that software type, selection steps, and certain factors influencing the purchase were related to whether the respondents felt the software improved the scheduling and financial analysis practice activities. Specifically, practices that selected electronic medical record or practice management software, that made software comparisons, or that considered prior user testimony as important were more likely to have perceived improvements in the scheduling process than were other practices. Practices that considered value important, that did not consider compatibility important, that selected managed care software, that spent less than $10,000, or that provided learning time (most dramatic increase in odds ratio, 8.2) during implementation were more likely to perceive that the software had improved the financial analysis process than were other practices. CONCLUSION: Perhaps one of the most important predictors of improvement was providing learning time during implementation, particularly when the software involves several practice activities. Despite this importance, less than half of the practices reported performing this step
Pulmonary Toxicity after a Quick Course of Combinatorial Vincristine, Bleomycin, and Cisplatin Neoadjuvant Chemotherapy in Cervical Cancer
Pulmonary toxicity is one of the most serious adverse effects associated with a quick course of vincristine, bleomycin, and cisplatin neoadjuvant chemotherapy (NAC-VBP). The aim of this study was to evaluate pulmonary toxicity related to a quick course NAC-VBP. A total of consecutive 61 patients, who underwent at most 3 cycles of NAC-VBP every 10 days in the International Federation of Gynecology and Obstetrics (FIGO) stage IB-IIB cervical cancer from 1995 to 2007, were retrospectively analyzed. Of the 61 study subjects, 7 (11.5%) were identified to have pulmonary toxicity and 2 (3.3%) died of pulmonary fibrosis progression despite aggressive treatment and the use of a multidisciplinary approach. No factor predisposing pulmonary toxicity was identified. Initial symptoms were non-specific, but bronchiolitis obliterans organizing pneumonia and interstitial pneumonitis were characteristic findings by high-resolution computed tomography of the chest. The benefit of steroid therapy was uncertain and was associated with steroid-induced diabetes mellitus requiring insulin therapy in two patients. Fatal pulmonary toxicity is a major concern of a quick course NAC-VBP. In conclusion, these patients require special monitoring for bleomycin-induced pulmonary toxicity
AGN-Host Galaxy Connection: Morphology and Colours of X-ray Selected AGN at z < 2
The connection between AGN and their host galaxies has been widely studied
over recent years, showing it to be of great importance for providing answers
to some fundamental questions related with AGN fueling mechanisms, their
formation and evolution. Using X-ray and one of the deepest broad-band optical
data sets, we studied morphology and colours in relationship with X-ray
properties for sources at redshifts z < 2.0, using a sample of 262 AGN in the
Subaru/XMM-Newton Deep Survey (SXDS). Morphological classification was obtained
using the galSVM code, one of the new methods useful especially when dealing
with high-redshift sources and low-resolution data. Colour-magnitude diagrams
were studied in relationship with redshift, morphology, X-ray obscuration, and
X-ray-to-optical flux ratio. Finally, the significance of different regions was
analysed on colour-magnitude diagrams, relating the observed properties of AGN
populations with some models of their formation and evolution.Comment: 24 pages, 19 figures, accepted for publication in
Astronomy&Astrophysic
Black hole accretion and host galaxies of obscured quasars in XMM-COSMOS
We explore the connection between black hole growth at the center of obscured
quasars selected from the XMM-COSMOS survey and the physical properties of
their host galaxies. We study a bolometric regime ( 8 x 10^45 erg/s)
where several theoretical models invoke major galaxy mergers as the main
fueling channel for black hole accretion. We confirm that obscured quasars
mainly reside in massive galaxies (Mstar>10^10 Msun) and that the fraction of
galaxies hosting such powerful quasars monotonically increases with the stellar
mass. We stress the limitation of the use of rest-frame color-magnitude
diagrams as a diagnostic tool for studying galaxy evolution and inferring the
influence that AGN activity can have on such a process. We instead use the
correlation between star-formation rate and stellar mass found for star-forming
galaxies to discuss the physical properties of the hosts. We find that at z ~1,
~62% of Type-2 QSOs hosts are actively forming stars and that their rates are
comparable to those measured for normal star-forming galaxies. The fraction of
star-forming hosts increases with redshift: ~71% at z ~2, and 100% at z ~3. We
also find that the the evolution from z ~1 to z ~3 of the specific
star-formation rate of the Type-2 QSO hosts is in excellent agreement with that
measured for star-forming galaxies. From the morphological analysis, we
conclude that most of the objects are bulge-dominated galaxies, and that only a
few of them exhibit signs of recent mergers or disks. Finally, bulge-dominated
galaxies tend to host Type-2 QSOs with low Eddington ratios (lambda<0.1), while
disk-dominated or merging galaxies have at their centers BHs accreting at high
Eddington ratios (lambda > 0.1).Comment: Accepted by A&A. 20 pages, 16 figures, 2 tables. A version with
higher resolution figures and SED fits of Appendix A is available at
http://www.eso.org/~vmainier/QSO2/qso2.pd
The CD3-Zeta Chimeric Antigen Receptor Overcomes TCR Hypo-Responsiveness of Human Terminal Late-Stage T Cells
Adoptive therapy of malignant diseases with tumor-specific cytotoxic T cells showed remarkable efficacy in recent trials. Repetitive T cell receptor (TCR) engagement of target antigen, however, inevitably ends up in hypo-responsive cells with terminally differentiated KLRG-1+ CD57+ CD7− phenotype limiting their therapeutic efficacy. We here revealed that hypo-responsiveness of CMV-specific late-stage CD8+ T cells is due to reduced TCR synapse formation compared to younger cells. Membrane anchoring of TCR components contributes to T cell hypo-responsiveness since dislocation of galectin-3 from the synapse by swainsonine restored both TCR synapse formation and T cell response. Transgenic expression of a CD3-zeta signaling chimeric antigen receptor (CAR) recovered hypo-responsive T cells to full effector functions indicating that the defect is restricted to TCR membrane components while synapse formation of the transgenic CAR was not blocked. CAR engineered late-stage T cells released cytokines and mediated redirected cytotoxicity as efficiently as younger effector T cells. Our data provide a rationale for TCR independent, CAR mediated activation in the adoptive cell therapy to avoid hypo-responsiveness of late-stage T cells upon repetitive antigen encounter
Rasch scaling procedures for informing development of a valid Fetal Surveillance Education Program multiple-choice assessment
<p>Abstract</p> <p>Background</p> <p>It is widely recognised that deficiencies in fetal surveillance practice continue to contribute significantly to the burden of adverse outcomes. This has prompted the development of evidence-based clinical practice guidelines by the Royal Australian and New Zealand College of Obstetricians and Gynaecologists and an associated Fetal Surveillance Education Program to deliver the associated learning. This article describes initial steps in the validation of a corresponding multiple-choice assessment of the relevant educational outcomes through a combination of item response modelling and expert judgement.</p> <p>Methods</p> <p>The Rasch item response model was employed for item and test analysis and to empirically derive the substantive interpretation of the assessment variable. This interpretation was then compared to the hierarchy of competencies specified a priori by a team of eight subject-matter experts. Classical Test Theory analyses were also conducted.</p> <p>Results</p> <p>A high level of agreement between the hypothesised and derived variable provided evidence of construct validity. Item and test indices from Rasch analysis and Classical Test Theory analysis suggested that the current test form was of moderate quality. However, the analyses made clear the required steps for establishing a valid assessment of sufficient psychometric quality. These steps included: increasing the number of items from 40 to 50 in the first instance, reviewing ineffective items, targeting new items to specific content and difficulty gaps, and formalising the assessment blueprint in light of empirical information relating item structure to item difficulty.</p> <p>Conclusion</p> <p>The application of the Rasch model for criterion-referenced assessment validation with an expert stakeholder group is herein described. Recommendations for subsequent item and test construction are also outlined in this article.</p
Checks and Balances in Autoimmune Vasculitis
Age-associated changes in the immune system including alterations in surface protein expression are thought to contribute to an increased susceptibility for autoimmune diseases. The balance between the expression of coinhibitory and costimulatory surface protein molecules, also known as immune checkpoint molecules, is crucial in fine-tuning the immune response and preventing autoimmunity. The activation of specific inhibitory signaling pathways allows cancer cells to evade recognition and destruction by the host immune system. The use of immune checkpoint inhibitors (ICIs) to treat cancer has proven to be effective producing durable antitumor responses in multiple cancer types. However, one of the disadvantages derived from the use of these agents is the appearance of inflammatory manifestations termed immune-related adverse events (irAEs). These irAEs are often relatively mild, but more severe irAEs have been reported as well including several forms of vasculitis. In this article, we argue that age-related changes in expression and function of immune checkpoint molecules lead to an unstable immune system, which is prone to tolerance failure and autoimmune vasculitis development. The topic is introduced by a case report from our hospital describing a melanoma patient treated with ICIs and who subsequently developed biopsy-proven giant cell arteritis. Following this case report, we present an in-depth review on the role of immune checkpoint pathways in the development and progression of autoimmune vasculitis and its relation with an aging immune system
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