312 research outputs found
JCV GCN in a Natalizumab-Treated MS Patient is Associated With Mutations of the VP1 Capsid Gene
Objective: To describe the clinical, neuroimaging, immunologic, and virologic characteristics of JC virus-associated granule cell neuronopathy (JCV GCN) in a natalizumab-treated patient with multiple sclerosis (MS) who developed immune reconstitution inflammatory syndrome (IRIS) after natalizumab withdrawal. Methods: We obtained longitudinal clinical data as well as MRI and proton magnetic resonance spectroscopy from this patient with MS. We measured JCV-specific cellular immune response in his peripheral blood by intracellular cytokine staining and sequenced a fragment of JCV VP1 capsid gene detected in his CSF. We contrast our findings with the first recently reported case. Results: This patient presented with worsening cerebellar symptoms and progressive cerebellar atrophy without new MS lesions on MRI after 63 months of natalizumab monotherapy. JCV DNA was detected in his CSF by PCR and harbored novel GCN-type mutations in the VP1 gene. He developed IRIS upon discontinuation of natalizumab and plasma exchange, which manifested itself by a worsening of clinical symptoms and contrast enhancement in the cerebellum on MRI. Treatment with corticosteroids resulted in resolution of IRIS, as demonstrated by proton magnetic resonance spectroscopy. The patient had a strong JCV-specific T-cell response in his peripheral blood and remains alive after 15 months from onset of symptoms, although with significant disability. He did not have MS relapse on glatiramer acetate. Conclusions: JCV GCN should be considered in patients on natalizumab presenting with progressive cerebellar symptoms and cerebellar atrophy, and is associated with mutations in the JCV VP1 gene. Natalizumab withdrawal may be complicated by JCV GCN IRIS, and require treatment with corticosteroids
Spinning particle in an external linearized gravitational wave field
We study the interaction of a scalar and a spinning particle with a coherent
linearized gravitational wave field treated as a classical spin two external
field. The spin degrees of freedom of the spinning particle are described by
skew-commuting variables. We derive the explicit expressions for the
eigenfunctions and the Green's functions of the theory. The discussion is exact
within the approximation of neglecting radiative corrections and we prove that
the result is completely determined by the semiclassical contribution.Comment: 11 page
Lessons from Love-Locks: The archaeology of a contemporary assemblage
This document is the Accepted Manuscript version. The final, definitive version of this paper has been published in Journal of Material Culture, November 2017, published by SAGE Publishing, All rights reserved.Loss of context is a challenge, if not the bane, of the ritual archaeologist’s craft. Those who research ritual frequently encounter difficulties in the interpretation of its often tantalisingly incomplete material record. Careful analysis of material remains may afford us glimpses into past ritual activity, but our often vast chronological separation from the ritual practitioners themselves prevent us from seeing the whole picture. The archaeologist engaging with structured deposits, for instance, is often forced to study ritual assemblages post-accumulation. Many nuances of its formation, therefore, may be lost in interpretation. This paper considers what insights an archaeologist could gain into the place, people, pace, and purpose of deposition by recording an accumulation of structured deposits during its formation, rather than after. To answer this, the paper will focus on a contemporary depositional practice: the love-lock. This custom involves the inscribing of names/initials onto a padlock, its attachment to a bridge or other public structure, and the deposition of the corresponding key into the water below; a ritual often enacted by a couple as a statement of their romantic commitment. Drawing on empirical data from a three-year diachronic site-specific investigation into a love-lock bridge in Manchester, UK, the author demonstrates the value of contemporary archaeology in engaging with the often enigmatic material culture of ritual accumulations.Peer reviewe
Abundance analysis of two late A-type stars HD 32115 and HD 37594
We have performed abundance analysis of two slowly rotating, late A-type
stars, HD 32115 (HR 1613) and HD 37594 (HR 1940), based on obtained echelle
spectra covering the spectral range 4000-9850 AAngstrom. These spectra allowed
us to identify an extensive line list for 31 chemical elements, the most
complete to date for A-type stars. Two approaches to abundance analysis were
used, namely a ``manual'' (interactive) and a semi-automatic procedure for
comparison of synthetic and observed spectra and equivalent widths. For some
elements non-LTE (NLTE) calculations were carried out and the corresponding
corrections have been applied. The abundance pattern of HD 32115 was found to
be very close to the solar abundance pattern, and thus may be used as an
abundance standard for chemical composition studies in middle and late A stars.
Further, its H-alpha line profile shows no core-to-wing anomaly like that found
for cool Ap stars and therefore also may be used as a standard in comparative
studies of the atmospheric structures of cool, slowly rotating Ap stars. HD
37594 shows a metal deficiency at the level of -0.3 dex for most elements and
triangle-like cores of spectral lines. This star most probably belongs to the
Delta Scuti group.Comment: 10 pages, 4 figure
Reverberation Mapping Results for Five Seyfert 1 Galaxies
We present the results from a detailed analysis of photometric and
spectrophotometric data on five Seyfert 1 galaxies observed as a part of a
recent reverberation mapping program. The data were collected at several
observatories over a 140-day span beginning in 2010 August and ending in 2011
January. We obtained high sampling-rate light curves for Mrk 335, Mrk 1501,
3C120, Mrk 6, and PG2130+099, from which we have measured the time lag between
variations in the 5100 Angstrom continuum and the H-beta broad emission line.
We then used these measurements to calculate the mass of the supermassive black
hole at the center of each of these galaxies. Our new measurements
substantially improve previous measurements of MBH and the size of the broad
line-emitting region for four sources and add a measurement for one new object.
Our new measurements are consistent with photoionization physics regulating the
location of the broad line region in active galactic nuclei.Comment: 45 pages, 5 figures. Accepted for publication in ApJ. For a brief
video explaining the key results of this paper, see
http://www.youtube.com/user/OSUAstronom
An Atlas of K-line Spectra for Cool Magnetic CP Stars: The Wing-Nib Anomaly (WNA)
We present a short atlas illustrating the unusual Ca {\sc ii} K-line profiles
in upper main sequence stars with anomalous abundances. Slopes of the profiles
for 10 cool, magnetic chemically peculiar (CP) stars change abruptly at the
very core, forming a deep "nib." The nibs show the same or nearly the same
radial velocity as the other atomic lines. The near wings are generally more
shallow than in normal stars. In three magnetic CP stars, the K-lines are too
weak to show this shape, though the nibs themselves are arguably present. The
Ca {\sc ii} H-lines also show deep nibs, but the profiles are complicated by
the nearby, strong H absorption. The K-line structure is nearly
unchanged with phase in CrB and Cir. Calculations, including
NLTE, show that other possibilities in addition to chemical stratification may
yield nib-like cores.Comment: 6 pages, 2 figures, and 8 figures; accepted for publication in ApJ
Reverberation Mapping of the Seyfert 1 Galaxy NGC 7469
A large reverberation mapping study of the Seyfert 1 galaxy NGC 7469 has
yielded emission-line lags for Hbeta 4861 and He II 4686 and a central black
hole mass measurement of about 10 million solar masses, consistent with
previous measurements. A very low level of variability during the monitoring
campaign precluded meeting our original goal of recovering velocity-delay maps
from the data, but with the new Hbeta measurement, NGC 7469 is no longer an
outlier in the relationship between the size of the Hbeta-emitting broad-line
region and the AGN luminosity. It was necessary to detrend the continuum and
Hbeta and He II 4686 line light curves and those from archival UV data for
different time-series analysis methods to yield consistent results.Comment: 9 Pages, 7 figures, 6 tables. Accepted for publication in The
Astrophysical Journa
Plugging a hole and lightening the burden: A process evaluation of a practice education team
Aim: To investigate the perceptions of clinical and senior managers about the role of Practice Educators employed in one acute hospital in the UK.
Background: Producing nurses who are fit for practice, purpose and academic award is a key issue for nurse education partnership providers in the UK. Various new models for practice learning support structures and new
roles within health care institutions have been established. To sustain funding and policy support for these models, there is a need for evaluation research.
Design: A process evaluation methodology was employed to determine the current value of a practice education team and to provide information to guide future direction.
Methods: Data were collected through semi-structured telephone interviews using a previously designed schedule. All senior nurse managers (N=5) and a purposive sample of clinical managers (n=13) who had personal experience of and perceptions about the role of practice educators provided the data. Interview notes were transcribed, coded and a thematic framework devised to present the results.
Results: A number of key themes emerged including: qualities needed for being a successful practice educator; visibility and presence of practice educators; providing a link with the university; ‘plugging a hole’ in supporting
learning needs; providing relief to practitioners in dealing with ‘the burden of students’; alleviating the ‘plight of students’; and effects on student attrition.
Conclusions: Findings provided evidence for the continued funding of the practice educator role with improvements to be made in dealing with stakeholder expectations and outcomes.
Relevance to clinical practice: In the UK, there still remain concerns about the fitness for practice of newly registered nurses, prompting a recent national consultation by the professional regulating body. Despite fiscal pressures, recommendations for further strengthening of all systems that will support the quality of practice learning may continue to sustain practice learning support roles
The Hamburg/ESO R-process Enhanced Star survey (HERES). V. Detailed abundance analysis of the r-process enhanced star HE 2327-5642
We report on a detailed abundance analysis of the strongly r-process enhanced
giant star, HE 2327-5642 ([Fe/H] = -2.78, [r/Fe] = +0.99). Determination of
stellar parameters and element abundances was based on analysis of high-quality
VLT/UVES spectra. The surface gravity was calculated from the NLTE ionization
balance between Fe I and Fe II, and Ca I and Ca II. Accurate abundances for a
total of 40 elements and for 23 neutron-capture elements beyond Sr and up to Th
were determined. The heavy element abundance pattern of HE 2327-5642 is in
excellent agreement with those previously derived for other strongly r-process
enhanced stars. Elements in the range from Ba to Hf match the scaled Solar
r-process pattern very well. No firm conclusion can be drawn with respect to a
relationship between the fisrt neutron-capture peak elements, Sr to Pd, in HE
2327-5642 and the Solar r-process, due to the uncertainty of the latter. A
clear distinction in Sr/Eu abundance ratios was found between the halo stars
with different europium enhancement. The strongly r-process enhanced stars
reveal a low Sr/Eu abundance ratio at [Sr/Eu] = -0.92+-0.13, while the stars
with 0 < [Eu/Fe] < 1 and [Eu/Fe] < 0 have 0.36 dex and 0.93 dex larger Sr/Eu
values, respectively. Radioactive dating for HE 2327-5642 with the observed
thorium and rare-earth element abundance pairs results in an average age of
13.3 Gyr, when based on the high-entropy wind calculations, and 5.9 Gyr, when
using the Solar r-residuals. HE 2327-5642 is suspected to be radial-velocity
variable based on our high-resolution spectra, covering ~4.3 years.Comment: 16 pages, 12 figures, accepted to A&
A Reverberation Lag for the High-Ionization Component of the Broad Line Region in the Narrow-Line Seyfert 1 Mrk 335
We present the first results from a detailed analysis of photometric and
spectrophotometric data on the narrow-line Seyfert 1 galaxy Mrk 335, collected
over a 120-day span in the fall of 2010. From these data we measure the lag in
the He II 4686 broad emission line relative to the optical continuum to be 2.7
\pm 0.6 days and the lag in the H\beta 4861 broad emission line to be 13.9 \pm
0.9 days. Combined with the line width, the He II lag yields a black hole mass,
MBH = (2.6 \pm 0.8)\times 10^7 Msun. This measurement is consistent with
measurements made using the H\beta 4861 line, suggesting that the He II
emission originates in the same region as H\beta, but at a much smaller radius.
This constitutes the first robust lag measurement for a high-ionization line in
a narrow-line Seyfert 1 galaxy.Comment: 7 pages, 3 figures. Accepted for publication in ApJ Letters. For a
brief video explaining the key results of this paper, see
http://www.youtube.com/user/OSUAstronomy#p/a/u/0/Z2UCxQG5iO
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