1,595 research outputs found
Optical Polarization of 52 Radio-Loud QSOs and BL Lac Objects
Polarization measurements are presented for 52 radio-loud QSOs and BL Lac
objects. For 9 highly polarized (p >3%) AGN, these are the first published
polarization measurements. Of these 9, 7 are highly-polarized QSOs (HPQs), one
is a BL Lac object and another is a likely BL Lac object. Polarization
variability is confirmed for some of these new and previously known
highly-polarized AGN. While 6 of the HPQs have flat radio spectra are almost
certainly blazars, PKS 1452-217 is probably a new member of the rare class of
radio-loud QSOs that show high polarization by scattering, and is therefore
important for testing orientation Unified Schemes. In competition for the
highest redshift HPQ are the well-observed QSO PKS 0438-43 at z = 2.85, with
maximum p = 4.7%, and PKS 0046-315 at z = 2.72, for which we find p = 13%.Comment: 6 pages. Astronomical Journal, in pres
The effects of drinks made from simple sugars on blood pressure in healthy older people
The objective of the research was to determine the blood pressure (BP) lowering effects in older people of 50 g carbohydrate drinks with varying carbohydrate content using a randomised, cross-over study with ten (six females) healthy older subjects (mean age 72·20 (SEM 1·50) years). BP, heart rate and glucometer-derived blood glucose levels were determined at baseline and following the ingestion of equal volumes (300 ml) of water and carbohydrate drinks with varying nutrient content (glucose, sucrose and fructose). A significant decline in BP over the first 60 min was seen following glucose (systolic BP (SBP) P,0·01, diastolic BP (DBP) P,0·01, mean arterial BP (MAP) P¼0·03) and sucrose (SBP P,0·01, DBP P,0·01, MAP P,0·01) ingestion, although the decrease occurred earlier after glucose than sucrose ingestion (SBP 7·33 (SEM 2·19) v. 21·00 (SEM 4·30) min (P¼0·03) and MAP 11·22 (SEM 3·10) v. 17·00 (SEM 3·78) min (P¼0·03)). BP increased after water ingestion (SBP P¼0·04, DBP P¼0·18, MAP P¼0·02) but did not change after fructose ingestion (SBP P¼0·36, DBP P¼0·81, MAP P¼0·34). Post hoc analyses revealed that the BP (SBP, DBP and MAP) decrease following glucose and sucrose ingestion were similar but significantly greater than following fructose or water ingestion. Sucrose, which is used widely (table sugar), reduces BP as much as glucose. In contrast to this, fructose ingestion causes no change in BP. Further studies are required to determine if the substitution of glucose or sucrose with fructose may be beneficial in the medical management of older people with severe symptomatic postprandial hypotension.R. Visvanathan, R. Chen, M. Garcia, M. Horowitz and I. Chapma
Perspectives of frailty and frailty screening: Protocol for a collaborative knowledge translation approach and qualitative study of stakeholder understandings and experiences
Accompanying the unprecedented growth in the older adult population worldwide is an increase in the prevalence of frailty, an age-related clinical state of increased vulnerability to stressor events. This increased vulnerability results in lower social engagement and quality of life, increased dependency, and higher rates of morbidity, health service utilization and mortality. Early identification of frailty is necessary to guide implementation of interventions to prevent associated functional decline. Consensus is lacking on how to clinically recognize and manage frailty. It is unknown how healthcare providers and healthcare consumers understand and perceive frailty, whether or not they regard frailty as a public health concern; and information on the indirect and direct experiences of consumer and healthcare provider groups towards frailty are markedly limited.We will conduct a qualitative study of consumer, practice nurse, general practitioner, emergency department physician, and orthopedic surgeons' perspectives of frailty and frailty screening in metropolitan and non-metropolitan South Australia. We will use tailored combinations of semi-structured interviews and arts-based data collection methods depending on each stakeholder group, followed by inductive and iterative analysis of data using qualitative description.Using stakeholder driven approaches to understanding and addressing frailty and frailty screening in context is critical as the prevalence and burden of frailty is likely to increase worldwide. We will use the findings from the Perceptions of Frailty and Frailty Screening study to inform a context-driven identification, implementation and evaluation of a frailty-screening tool; drive awareness, knowledge, and skills development strategies across stakeholder groups; and guide future efforts to embed emerging knowledge about frailty and its management across diverse South Australian contexts using a collaborative knowledge translation approach. Study findings will help achieve a coordinated frailty and healthy ageing strategy with relevance to other jurisdictions in Australia and abroad, and application of the stakeholder driven approach will help illuminate how its applicability to other jurisdictions.Mandy M. Archibald, Rachel Ambagtsheer, Justin Beilby, Mellick J. Chehade, Tiffany K. Gill, Renuka Visvanathan, and Alison L. Kitso
An Old Cluster in NGC 6822
We present spectroscopy of two clusters in the dwarf irregular galaxy NGC
6822. From these we deduce an age for Cluster VII of 11 Gyr and [Fe/H] = -1.95
+/- 0.15 dex. Cluster VII appears to be an analog of the metal-poor galactic
globular clusters. Cluster VI is found to be much younger and more metal rich,
with an age of approximately 2 Gyr. Its derived metallicity, [Fe/H], of
approximately -1.0 dex is comparable to that of the gas seen today in NGC 6822.
The existence of a metal-poor old cluster in NGC 6822 rules out models for the
chemical evolution of this galaxy with significant prompt initial enhancement.
We find that a star formation rate which is constant with time and is within a
factor of two of the present star formation rate can reproduce the two points
on the age-metallicity relationship for NGC 6822 over the past 10 Gyr defined
by these two clusters.Comment: 8 pages; accepted for publication in A
The Red-Sequence Luminosity Function in Galaxy Clusters since z~1
We use a statistical sample of ~500 rich clusters taken from 72 square
degrees of the Red-Sequence Cluster Survey (RCS-1) to study the evolution of
~30,000 red-sequence galaxies in clusters over the redshift range 0.35<z<0.95.
We construct red-sequence luminosity functions (RSLFs) for a well-defined,
homogeneously selected, richness limited sample. The RSLF at higher redshifts
shows a deficit of faint red galaxies (to M_V=> -19.7) with their numbers
increasing towards the present epoch. This is consistent with the `down-sizing`
picture in which star-formation ended at earlier times for the most massive
(luminous) galaxies and more recently for less massive (fainter) galaxies. We
observe a richness dependence to the down-sizing effect in the sense that, at a
given redshift, the drop-off of faint red galaxies is greater for poorer (less
massive) clusters, suggesting that star-formation ended earlier for galaxies in
more massive clusters. The decrease in faint red-sequence galaxies is
accompanied by an increase in faint blue galaxies, implying that the process
responsible for this evolution of faint galaxies is the termination of
star-formation, possibly with little or no need for merging. At the bright end,
we also see an increase in the number of blue galaxies with increasing
redshift, suggesting that termination of star-formation in higher mass galaxies
may also be an important formation mechanism for higher mass ellipticals. By
comparing with a low-redshift Abell Cluster sample, we find that the
down-sizing trend seen within RCS-1 has continued to the local universe.Comment: ApJ accepted. 11 pages, 5 figure
Markers of inflammation and bone remodelling associated with improvement in clinical response measures in psoriatic arthritis patients treated with golimumab
<p>Objective To determine serum biomarker associations with clinical response to golimumab treatment in patients with psoriatic arthritis (PsA).</p>
<p>Methods GO–REVEAL was a randomised, placebo-controlled study of golimumab in patients with active PsA. Samples were collected from 100 patients at baseline, week 4 and week 14, and analysed for serum-based biomarkers and protein profiling (total 92 markers); data were correlated with clinical measures at week 14.</p>
<p>Results Serum levels of a subset of proteins (apolipoprotein C III, ENRAGE, IL-16, myeloperoxidase, vascular endothelial growth factor, pyridinoline, matrix metalloproteinase 3, C-reactive protein (CRP), carcinoembryonic antigen, intercellular adhesion molecule 1 and macrophage inflammatory protein 1α) at baseline or week 4 were strongly associated with American College of Rheumatology 20% improvement (ACR20) response and/or disease activity score in 28 joints (DAS28) at week 14. A smaller subset of proteins was significantly associated with a 75% improvement in the psoriasis area and severity index score (PASI75) at week 14, (adiponectin, apolipoprotein CIII, serum glutamic oxaloacetic transaminase, and tumour necrosis factor α). Subsets of proteins were identified as potentially predictive of clinical response for each of the clinical measures, and the power of these biomarker panels to predict clinical response to golimumab treatment was stronger than for CRP alone.</p>
<p>Conclusions This analysis provides insight into several panels of markers that may have utility in identifying PsA patients likely to have ACR20, DAS28, or PASI75 responses following golimumab treatment.</p>
Comparative effects of glucose and water drinks on blood pressure and cardiac function in older subjects with and without postprandial hypotension
Postprandial hypotension (PPH) occurs frequently and is thought to reflect an inadequate increase in cardiac output to compensate for the rise in splanchnic blood flow after a meal. Gastric distension by water attenuates the postprandial fall in blood pressure (BP). Cardiac hemodynamics (stroke volume (SV), cardiac output (CO), and global longitudinal strain (GLS)) have hitherto not been measured in PPH We sought to determine the comparative effects of water and glucose drinks on cardiac hemodynamics in healthy older subjects and individuals with PPH Eight healthy older subjects (age 71.0 ± 1.7 years) and eight subjects with PPH (age 75.5 ± 1.0 years) consumed a 300 mL drink of either water or 75 g glucose (including 150 mg 13C-acetate) in randomized order. BP and heart rate (HR) were measured using an automatic device, SV, CO, and GLS by transthoracic echocardiography and gastric emptying by measurement of 13CO2 In both groups, glucose decreased systolic BP (P < 0.001) and increased HR, SV, and CO (P < 0.05 for all). The fall in systolic BP was greater (P < 0.05), and increase in HR less (P < 0.05), in the PPH group, with no difference in SV or CO Water increased systolic BP (P < 0.05) in subjects with PPH and, in both groups, decreased HR (P < 0.05) without affecting SV, CO, or GLS In subjects with PPH, the hypotensive response to glucose and the pressor response to water were related (R = -0.75, P < 0.05). These observations indicate that, in PPH, the hypotensive response to oral glucose is associated with inadequate compensatory increases in CO and HR, whereas the pressor response to water ingestion is maintained and, possibly, exaggerated.Laurence G. Trahair, Sharmalar Rajendran, Renuka Visvanathan, Matthew Chapman, Daniel Stadler, Michael Horowitz and Karen L. Jone
The bright galaxy population of five medium redshift clusters. I. Color-Magnitude Relation, Blue Fractions and Visual Morphology
Using data of five clusters of galaxies within the redshift range 0.15
z 0.25, imaged with the Nordic Optical Telescope (NOT) in the central
1 Mpc in very good seeing conditions, we have performed an
exhaustive inspection of their bright galaxy population. That range of
redshift, where only a small amount of data with the required resolution and
quality is available, is particularly important for the understanding of the
formation and evolution of clusters of galaxies. We have inspected the
color-magnitude relation (CMR) for those clusters and measured the blue
fraction of galaxies in their cores to check for evidence of evolution as found
in other works. Moreover, the visual classification of the galaxy morphology
has been performed and the morphology-radius relation has been examined We have
not found signs of evolution neither in the slope of the CMR nor in the blue
fraction of galaxies. A diversity of situations regarding those parameters and
in the morphological mixing has been noticed, with two out of five clusters
containing a dominant late-type core population. The cluster A1878 stands out
as some of its properties differ from those of the other clusters in the
sample.
No clear signs of evolution appear in our analysis. The data support the view
that the morphology and the stellar content of the galaxies in our clusters
have been already settled at z 0.2. Only the fraction of interacting
galaxies in the clusters appear to be larger than in clusters like Coma
although the number of clusters in the sample is small to give a definitive
conclusion.Comment: 16 pages, 8 figures, 4 tables, 1 longtable The paper has been already
accepted but still not publishe
Photometric validation of a model independent procedure to extract galaxy clusters
By means of CCD photometry in three bands (Gunn g, r, i) we investigate the
existence of 12 candidate clusters extracted via a model independent peak
finding algorithm (\cite{memsait}) from DPOSS data. The derived color-magnitude
diagrams allow us to confirm the physical nature of 9 of the cluster
candidates, and to estimate their photometric redshifts. Of the other
candidates, one is a fortuitous detection of a true cluster at z~0.4, one is a
false detection and the last is undecidable on the basis of the available data.
The accuracy of the photometric redshifts is tested on an additional sample of
8 clusters with known spectroscopic redshifts. Photometric redshifts turn out
to be accurate within z~0.01 (interquartile range).Comment: A&A in pres
Planetary Nebulae as standard candles XI. Application to Spiral Galaxies
We report the results of an [O III] lambda 5007 survey for planetary nebulae
(PN) in three spiral galaxies: M101 (NGC 5457), M51 (NGC 5194/5195) and M96
(NGC 3368). By comparing on-band/off-band [O III] lambda 5007 images with
images taken in H-alpha and broadband R, we identify 65, 64 and 74 PN
candidates in each galaxy, respectively. From these data, an adopted M31
distance of 770 kpc, and the empirical planetary nebula luminosity function
(PNLF), we derive distances to M101, M51, and M96 of 7.7 +/- 0.5, 8.4 +/- 0.6,
and 9.6 +/- 0.6 Mpc. These observations demonstrate that the PNLF technique can
be successfully applied to late-type galaxies, and provide an important overlap
between the Population I and Population II distance scales. We also discuss
some special problems associated with using the PNLF in spiral galaxies,
including the effects of dust and the possible presence of [O III] bright
supernova remnants.Comment: 38 pages, TeX, with tables included but not figures. Uses epsf.tex
and kpnobasic.tex. To be published in the Astophysical Journal. Full paper is
available at http://www.astro.psu.edu/users/johnf/Text/research.htm
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