2,239 research outputs found
Joint Planck and WMAP Assessment of Low CMB Multipoles
The remarkable progress in cosmic microwave background (CMB) studies over
past decade has led to the era of precision cosmology in striking agreement
with the CDM model. However, the lack of power in the CMB temperature
anisotropies at large angular scales (low-), as has been confirmed by the
recent Planck data also (up to ), although statistically not very
strong (less than ), is still an open problem. One can avoid to seek
an explanation for this problem by attributing the lack of power to cosmic
variance orcan look for explanations i.e., different inflationary potentials or
initial conditions for infl ation to begin with, non-trivial topology, ISW
effect etc. Features in the primordial power spectrum (PPS) motivated by the
early universe physics has been the most common solution to address this
problem. In the present work we also follow this approach and consider a set of
PPS which have features and constrain the parameters of those using WMAP 9 year
and Planck data employing Markov-Chain Monte Carlo (MCMC) analysis. The
prominent feature of all the models of PPS that we consider is an infra-red cut
off which leads to suppression of power at large angular scales. We consider
models of PPS with maximum three extra parameters and use Akaike information
criterion () and Bayesian information criterion () of model and
Bayesian information criterion () of model selection to compare the
models. For most models, we find good constraints for the cut off scale ,
however, for other parameters our constraints are not that good. We find that
sharp cut off model gives best likelihood value for the WMAP 9 year data, but
is as good as power law model according to . For the joint WMAP 9+Planck
data set, Starobinsky model is slightly preferred by which is also able
to produce CMB power suppression up to to some extent.Comment: 27 pages, 10 figures, 3 tables, matches with the published version,
abstract is shortened to keep it within arXiv's limit (1920 characters
Mega doses of methotrexate in the treatment of osteosarcoma
Abstract is not provided by the author/publishe
Little evidence for entropy and energy excess beyond - An end to ICM preheating?
Non-gravitational feedback affects the nature of the intra-cluster medium
(ICM). X-ray cooling of the ICM and in situ energy feedback from AGN's and SNe
as well as {\it preheating} of the gas at epochs preceding the formation of
clusters are proposed mechanisms for such feedback. While cooling and AGN
feedbacks are dominant in cluster cores, the signatures of a preheated ICM are
expected to be present even at large radii. To estimate the degree of
preheating, with minimum confusion from AGN feedback/cooling, we study the
excess entropy and non-gravitational energy profiles upto for a
sample of 17 galaxy clusters using joint data sets of {\it Planck} SZ pressure
and {\it ROSAT/PSPC} gas density profiles. The canonical value of preheating
entropy floor of keV cm, needed in order to match cluster
scalings, is ruled out at . We also show that the feedback
energy of 1 keV/particle is ruled out at 5.2 beyond . Our
analysis takes both non-thermal pressure and clumping into account which can be
important in outer regions. Our results based on the direct probe of the ICM in
the outermost regions do not support any significant preheating.Comment: 6 pages, 4 figures, 1 table, Accepted in MNRAS Letter
Excess entropy and energy feedback from within cluster cores up to r
We estimate the "non-gravitational" entropy-injection profiles, ,
and the resultant energy feedback profiles, , of the intracluster
medium for 17 clusters using their Planck SZ and ROSAT X-Ray observations,
spanning a large radial range from up to . The feedback
profiles are estimated by comparing the observed entropy, at fixed gas mass
shells, with theoretical entropy profiles predicted from non-radiative
hydrodynamic simulations. We include non-thermal pressure and gas clumping in
our analysis. The inclusion of non-thermal pressure and clumping results in
changing the estimates for and by 10\%-20\%. When
clumpiness is not considered it leads to an under-estimation of keV cm at and keV cm at
. On the other hand, neglecting non-thermal pressure results in an
over-estimation of keV cm at and
under-estimation of keV cm at . For the
estimated feedback energy, we find that ignoring clumping leads to an
under-estimation of energy per particle keV at and
keV at . Similarly, neglect of the non-thermal
pressure results in an over-estimation of keV at
and under-estimation of keV at . We find entropy
floor of keV cm is ruled out at
throughout the entire radial range and keV at more than
3 beyond , strongly constraining ICM pre-heating scenarios. We
also demonstrate robustness of results w.r.t sample selection, X-Ray analysis
procedures, entropy modeling etc.Comment: 17 pages, 15 figures, 5 tables, Accepted in MNRA
AGN feedback with the Square Kilometer Array (SKA) and implications for cluster physics and cosmology
AGN feedback is regarded as an important non-gravitational process in galaxy
clusters, providing useful constraints on large-scale structure formation. It
modifies the structure and energetics of the intra-cluster medium (ICM) and
hence its understanding is crucially needed in order to use clusters as high
precision cosmological probes. In this context, particularly keeping in mind
the upcoming high quality radio data expected from radio surveys like SKA with
its higher sensitivity, high spatial and spectral resolutions, we review our
current understanding of AGN feedback, its cosmological implications and the
impact that SKA can have in revolutionizing our understanding of AGN feedback
in large-scale structures. Recent developments regarding the AGN outbursts and
its possible contribution to excess entropy in the hot atmospheres of groups
and clusters, its correlation with the feedback energy in ICM, quenching of
cooling flows and the possible connection between cool core clusters and radio
mini-halos, are discussed. We describe current major issues regarding modeling
of AGN feedback and its impact on the surrounding medium. With regard to the
future of AGN feedback studies, we examine the possible breakthroughs that can
be expected from SKA observations. In the context of cluster cosmology, for
example, we point out the importance of SKA observations for cluster mass
calibration by noting that most of clusters discovered by eROSITA X-ray
mission can be expected to be followed up through a 1000 hour SKA-1 mid
programme. Moreover, approximately radio mini halos and
radio halos at can be potentially detected by SKA1 and SKA2 and used as
tracers of galaxy clusters and determination of cluster selection function.Comment: 14 pages, 10 figures, Review article accepted in Journal of
Astrophysics and Astronomy (JOAA
Endoscopic Submucosal Tunnel Dissection as a Novel Therapeutic Technique in Patients With Barrett’s Esophagus
© 2020 American Federation for Medical Research. With the ameliorated resectability prowess of endoscopic techniques, a myriad of diseases previously treated by major ablative surgeries are now endoscopically curable. Endoscopic submucosal tunnel dissection (ESTD) is a relatively new technique that has diversified endoscopic application. Although ESTD has frequently been used for the resection of esophageal neoplastic lesions, the clinical evidence pertaining to its efficacy in the treatment of circumferential Barrett’s esophagus remains sparse. In this study, we evaluated ESTD as a potential therapeutic technique in patients with Barrett’s esophagus-related high-grade dysplasia. The tunneling strategy helped achieve complete en bloc resection at an increased dissection speed, without any procedural complications. This article illustrates that ESTD can be a feasible, safe, and effective treatment for dysplastic Barrett’s esophagus. Future research should aim to stratify the potential risks and complications associated with this optimization of endoscopic submucosal dissection in patients with superficial esophageal lesions
Genetic basis of variation for seedling traits in Gossypium hirsutum L.
A 6 × 6 complete diallel analysis was performed to study the inheritance of seedling traits in cotton. Significant differences among genotypes showed the genetic variation and formal analysis predicted the presence of both additive and non-additive genetic variation for inheritance of seedling traits. Further, the estimates of genetic components D, H1 and H2 confirmed the presence of both additive and non-additive genetic effects for all the characteristics. Dominant genes were responsible for theincrease of seedling shoot length, root length, shoot weight and root weight. However, recessive genes were accountable for the increase of shoot root ratio by length and by weight. Seedling shoot length, root length and root weight can be improved through heterosis breeding. The magnitude of broad sense heritability was greater than narrow sense for all the six traits under study hence diminished the scope of selection in the early segregating generation therefore pedigree breeding method is suggested for the improvement of these traits.Key words: Additive dominance model, gene action, Gossypium hirsutum L, heritability, seedling traits
Response of Chickpea Lines to Ascochyta rabiei at Two Growing Stages
During winter 2004 and 2005, two field and glasshouse experiments were conducted to evaluate the response of 471 chickpea genotypes to Ascochyta rabiei, as Ascochyta blight (AB) disease in Chickpea (Cicer aurietimum). Frequent rainfall at flowering and pod formation stages made favorite conditions conducive for the infection and symptoms expression. So, the genotypes with high level of tolerance at seedling stage proved response to the pathogen under field condition. Disease at seedling and adult plant stage exhibited high association, although level of infection was higher at adult plant stage. In glasshouse 65 genotypes at seedling stage and in field experiment 14 genotypes at pod formation stage were resistant to the pathogen. Following green house and field screening methods, six genotypes FLIP98-229C, FLIP82-150C,NCS 950204, NCS 950219, NCS 9903 and PaidarxParbat from NARC and six lines (FLIP 00-20C, FLIP 02-18C, FLIP 02-44C, FLIP 97-120C, FLIP 02-39C and FLIP 97-102C) from ICARDA found resistant for multilocational / agronomic evaluation and use as resistant parent trials for high yielding AB resistance breeding varieties
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