1,874 research outputs found
X-ray observations of the galaxy cluster PKS 0745-191: To the virial radius, and beyond
We measure X-ray emission from the outskirts of the cluster of galaxies PKS
0745-191 with Suzaku, determining radial profiles of density, temperature,
entropy, gas fraction, and mass. These measurements extend beyond the virial
radius for the first time, providing new information about cluster assembly and
the diffuse intracluster medium out to ~1.5 r_200, (r_200 ~ 1.7 Mpc ~ 15'). The
temperature is found to decrease by roughly 70 per cent from 0.3-1 r_200. We
also see a flattening of the entropy profile near the virial radius and
consider the implications this has for the assumption of hydrostatic
equilibrium when deriving mass estimates. We place these observations in the
context of simulations and analytical models to develop a better understanding
of non-gravitational physics in the outskirts of the cluster.Comment: 10 pages, 11 figures, accepted to MNRAS; expanded discussion of
analysis and uncertainties, results qualitatively unchange
Searching for cool and cooling X-ray emitting gas in 45 galaxy clusters and groups
We present a spectral analysis of cool and cooling gas in 45 cool-core
clusters and groups of galaxies obtained from Reflection Grating Spectrometer
(RGS) XMM- observations. The high-resolution spectra show FeXVII
emission in many clusters, which implies the existence of cooling flows. The
cooling rates are measured between the bulk Intracluster Medium (ICM)
temperature and 0.01 keV and are typically weak, operating at less than a few
tens of in clusters, and less than 1 in groups of galaxies. They are 10-30% of the classical
cooling rates in the absence of heating, which suggests that AGN feedback has a
high level of efficiency. If cooling flows terminate at 0.7 keV in clusters,
the associated cooling rates are higher, and have a typical value of a few to a
few tens of . Since the soft X-ray emitting region,
where the temperature keV, is spatially associated with H
nebulosity, we examine the relation between the cooling rates above 0.7 keV and
the H nebulae. We find that the cooling rates have enough energy to
power the total UV-optical luminosities, and are 5 to 50 times higher than the
observed star formation rates for low luminosity objects. In 4 high luminosity
clusters, the cooling rates above 0.7 keV are not sufficient and an inflow at a
higher temperature is required. Further residual cooling below 0.7 keV
indicates very low complete cooling rates in most clusters.Comment: 17 pages, 10 figures, accepted for publication in MNRA
Gill's model of the Antarctic Circumpolar Current, revisited: the role of latitudinal variations in wind stress
Adrian Gill’s (1968) model of the Antarctic Circumpolar Current (ACC) is reinterpreted for a stratified, reduced-gravity ocean, where the barotropic streamfunction is replaced by the pycnocline depth, and the bottom drag coefficient by the Gent and McWilliams eddy diffusivity. The resultant model gives a simple description of the lateral structure of the ACC that is consistent with contemporary descriptions of ACC dynamics. The model is used to investigate and interpret the sensitivity of the ACC to the latitudinal profile of the surface wind stress. A substantial ACC remains when the wind jet is shifted north of the model Drake Passage, even by several thousand kilometers. The integral of the wind stress over the circumpolar streamlines is found to be a useful predictor of the magnitude of the volume transport through the model Drake Passage, although it is necessary to correct for basin-wide zonal pressure gradients in order to obtain good quantitative agreement
Effects of HIF-1α and HIF2α on Growth and Metabolism of Clear-Cell Renal Cell Carcinoma 786-0 Xenografts
In cultured clear-cell renal carcinoma (CCRCC) 786-0 cells transfected with HIF1α (HIF-1+), HIF-2α (HIF-2+), or empty vector (EV), no significant differences were observed in the growth rates in vitro, but when grown in vivo as xenografts HIF-2α significantly increased, and HIF-1α significantly decreased growth rates, compared to EV tumors. Factors associated with proliferation were increased and factors associated with cell death were decreased in HIF-2+ tumors. Metabolite profiles showed higher glucose and lower lactate and alanine levels in the HIF-2+ tumors whilst immunostaining demonstrated higher pyruvate dehydrogenase and lower pyruvate dehydrogenase kinase 1, compared to control tumors. Taken together, these results suggest that overexpression of HIF-2α in CCRCC 786-0 tumors regulated growth both by maintaining a low level of glycolysis and by allowing more mitochondrial metabolism and tolerance to ROS induced DNA damage. The growth profiles observed may be mediated by adaptive changes to a more oxidative phenotype
Molecular Flows in Contemporary Active Galaxies and the Efficacy of Radio-Mechanical Feedback
Molecular gas flows are analysed in 14 cluster galaxies (BCGs) centred in cooling hot atmospheres. The BCGs contain 109−1011 M⊙ of molecular gas, much of which is being moved by radio jets and lobes. The molecular flows and radio jet powers are compared to molecular outflows in 45 active galaxies within z < 0.2. We seek to understand the relative efficacy of radio, quasar, and starburst feedback over a range of active galaxy types. Molecular flows powered by radio feedback in BCGs are ∼10–1000 times larger in extent compared to contemporary galaxies hosting quasar nuclei and starbursts. Radio feedback yields lower flow velocities but higher momenta compared to quasar nuclei, as the molecular gas flows in BCGs are usually ∼10–100 times more massive. The product of the molecular gas mass and lifting altitude divided by the AGN or starburst power – a parameter referred to as the lifting factor – exceeds starbursts and quasar nuclei by 2–3 orders of magnitude, respectively. When active, radio feedback is generally more effective at lifting gas in galaxies compared to quasars and starburst winds. The kinetic energy flux of molecular clouds generally lies below and often substantially below a few per cent of the driving power. We find tentatively that star formation is suppressed in BCGs relative to other active galaxies, perhaps because these systems rarely form molecular discs that are more impervious to feedback and are better able to promote star formation
Destined to die in hospital? Systematic review and meta-analysis of place of death in haematological malignancy
<p>Abstract</p> <p>Background</p> <p>Haematological malignancies are a common, heterogeneous and complex group of diseases that are often associated with poor outcomes despite intensive treatment. Research surrounding end-of-life issues, and particularly place of death, is therefore of paramount importance, yet place of death has not been formally reviewed in these patients.</p> <p>Methods</p> <p>A systematic literature review and meta-analysis was undertaken using PubMed to identify all studies published between 1966 and 2010. Studies examining place of death in adult haematology patients, using routinely compiled morbidity and mortality data and providing results specific to this disease were included. 21 studies were identified with descriptive and/or risk-estimate data; 17 were included in a meta-analysis.</p> <p>Results</p> <p>Compared to other cancer deaths, haematology patients were more than twice as likely to die in hospital (Odds Ratio 2.25 [95% Confidence Intervals, 2.07-2.44]).</p> <p>Conclusion</p> <p>Home is generally considered the preferred place of death but haematology patients usually die in hospital. This has implications for patients who may not be dying where they wish, and also health commissioners who may be funding costly end-of-life care in inappropriate acute hospital settings. More research is needed about preferred place of care for haematology patients, reasons for hospital deaths, and how these can be avoided if home death is preferred.</p
Astrophysical Limits on Very Light Axion-like Particles from Chandra Grating Spectroscopy of NGC 1275
Axions/axion-like particles (ALPs) are a well motivated extension of the
Standard Model and are generic within String Theory. The X-ray transparency of
the intracluster medium (ICM) in galaxy clusters is a powerful probe of light
ALPs (with mass ); as X-ray photons from an embedded or
background source propagate through the magnetized ICM, they may undergo
energy-dependent quantum mechanical conversion into ALPs (and vice versa),
imprinting distortions on the X-ray spectrum. We present Chandra data for the
active galactic nucleus NGC1275 at the center of the Perseus cluster. Employing
a 490ks High-Energy Transmission Gratings (HETG) exposure, we obtain a
high-quality 1-9keV spectrum free from photon pileup and ICM contamination.
Apart from iron-band features, the spectrum is described by a power-law
continuum, with any spectral distortions at the level. We compute photon
survival probabilities as a function of ALP mass and ALP-photon coupling
constant for an ensemble of ICM magnetic field models, and then
use the NGC1275 spectrum to constraint the -plane.
Marginalizing over magnetic field realizations, the 99.7% credible region
limits the ALP-photon coupling to (depending upon magnetic field model) for masses . These are the most stringent limit to date on
for these light ALPs, and have already reached the sensitivity
limits of next-generation helioscopes and light-shining-through-wall
experiments. We highlight the potential of these studies with the
next-generation X-ray observatories Athena and Lynx, but note the critical
importance of advances in relative calibration of these future X-ray
spectrometers.Comment: Published in The Astrophysical Journal, 2020, vol 890, pp59. This
posting corrects typos in equation (2) and the likelihood function just prior
to equation (3). Typos were introduced into the draft at late stage and the
analysis is correc
Nutritional Content, Phytochemical Profiling, and Physical Properties of Buckwheat (Fagopyrum esculentum) Seeds for Promotion of Dietary and Food Ingredient Biodiversity
Acknowledgments: The authors would like to thank to Donna Henderson, Lynn Pirie, and Jodie Park, from the Rowett Institute Analytical Department for doing the proximate, amino acid, and ICPMS analysis; and to the funders: Scottish Government′s Rural and Environment Science and Analytical Services Division (RESAS) and Ministério da Educação Coordenação de Aperfeiçoamento de Pessoal de Nível Superior Brazil (CAPES). Funding: This research was funded by the Scottish Government′s Rural and Environment Science and Analytical Services Division (RESAS) as part of the Strategic Research Programme 2016–2021 Crops 2022, 2, 3 303 and Ministério da Educação Coordenação de Aperfeiçoamento de Pessoal de Nível Superior–CAPES, Brazil.Peer reviewedPublisher PD
The G-protein-coupled receptor CLR is upregulated in an autocrine loop with adrenomedullin in clear cell renal cell carcinoma and associated with poor prognosis
Purpose: The G-protein-coupled receptor (GPCR) calcitonin receptor-like receptor (CLR) and its ligand peptide adrenomedullin (encoded by ADM gene) are implicated in tumor angiogenesis in mouse models but poorly defined in human cancers. We therefore investigated the diagnostic/prognostic use for CLR in human tumor types that may rely on adrenomedullin signaling and in clear cell renal cell carcinoma (RCC), a highly vascular tumor, in particular. Experimental Design: In silico gene expression mRNA profiling microarray study (n = 168 tumors) and cancer profiling cDNA array hybridization (n=241 pairs of patient-matched tumor/normal tissue samples) were carried out to analyze ADM mRNA expression in 13 tumor types. Immunohistochemistry on tissue microarrays containing patient-matched renal tumor/normal tissues (n = 87 pairs) was conducted to study CLR expression and its association with clinicopathologic parameters and disease outcome. Results: ADM expression was significantly upregulated only in RCC and endometrial adenocarcinoma compared with normal tissue counterparts (P < 0.01). CLR was localized in tumor cells and vessels in RCC and upregulated as compared with patient-matched normal control kidney (P < 0.001). Higher CLR expression was found in advanced stages (P < 0.05), correlated with high tumor grade (P < 0.01) and conferred shorter overall survival (P < 0.01). Conclusions: In human tissues ADM expression is upregulated in cancer type-specific manner, implicating potential role for adrenomedullin signaling in particular in RCC, where CLR localization suggests autocrine/paracrine mode for adrenomedullin action within the tumor microenvironment. Our findings reveal previously unrecognized CLR upregulation in an autocrine loop with adrenomedullin in RCCwith potential application for this GPCR as a target for future functional studies and drug development. © 2013 AACR
- …