16,837 research outputs found
Byssoloma subdiscordans (Nyl.) P. James: Distributional range and its habitat preference in Indian subcontinent
The present paper deals with the new distributional record of Byssoloma subdiscordans for Western Himalayan lichen flora and a new habitat record for Indian subcontinent. A note on its brief taxonomic description, distribution, ecology and occurrence in India is also provided. Previously the species was reported as corticolous and foliicolous from tropical and montane regions of India, viz. Eastern Himalaya and Western Ghats, but this is for the first time that authors have reported it as saxicolous in temperate regions of Western Himalaya, thus extending its habitat preference along with distributional range within Indian subcontinent
COMPARATIVE STUDY OF ANTI-INFLAMMATORY ACTIVITY OF AQUEOUS AND METHANOLIC EXTRACTS OF HIBISCUS CANNABINUS LEAF (MALVACEAE)
Objective: The present study was undertaken to investigate and compare the anti-inflammatory activity of an aqueous and methanolic extract of Hibiscus cannabinus (Malvaceae) using carrageenan-induced rat paw edema.Methods: Aqueous and methanolic extracts of Hibiscus cannabinus was prepared and tested for anti-inflammatory activity in female spargue dawley rat weighing 150-180 g. The animals were randomly divided into 6 groups of 6 each. First group served as vehicle control, second group served as standard, third and fourth group served as high (400 mg/kg) and low (200 mg/kg) dose of methanolic extract of Hibiscus cannabinus leaves (MHCL) respectively and fifth and sixth group as high (400 mg/kg) and low (200 mg/kg) dose of aqueous extract of Hibiscus cannabinus leaves (AHCL) respectively. The In vivo anti-inflammatory activity was studied using carrageenan induce rat paw edema animal model. The estimation of liver and blood parameters consist of serum glutamic oxalate transaminase (SGOT), serum glutamic pyruvate transaminase (SGPT), lipid peroxidation (LPO), reduced glutathione (GSH) and superoxide dismutase (SOD).Results: Both MHCL and AHCL extracts showed significant (*p<0.05) inhibition of rat paw edema in dose-dependent manner. The maximum percent inhibition in paw edema was found in MHCL at dose of 400 mg/kg was 52.00% and AHCL at dose of 400 mg/kg was 49.93%. Both MHCL and AHCL at dose of 400 mg/kg reduce LPO level as 31.10 nmol/g and 35.23 nmol/g respectively when compared with standard indomethacin.Conclusion: An anti-inflammatory activity was found in both MHCL and AHCL extracts. But the MHCL showed more significant anti-inflammatory activity.Keywords: Hibiscus cannabinus, Anti-inflammatory, Carrageenan, Indomethacin, EdemaÂ
Near-IR studies of recurrent nova V745 Scorpii during its 2014 outburst
The recurrent nova (RN) V745 Scorpii underwent its third known outburst on
2014 February 6. Infrared monitoring of the eruption on an almost daily basis,
starting from 1.3d after discovery, shows the emergence of a powerful blast
wave generated by the high velocity nova ejecta exceeding 4000 kms
plowing into its surrounding environment. The temperature of the shocked gas is
raised to a high value exceeding 10K immediately after outburst
commencement. The energetics of the outburst clearly surpass those of similar
symbiotic systems like RS Oph and V407 Cyg which have giant secondaries. The
shock does not show a free-expansion stage but rather shows a decelerative
Sedov-Taylor phase from the beginning. Such strong shockfronts are known to be
sites for ray generation. V745 Sco is the latest nova, apart from five
other known novae, to show ray emission. It may be an important
testbed to resolve the crucial question whether all novae are generically
ray emitters by virtue of having a circumbinary reservoir of material
that is shocked by the ejecta rather than ray generation being
restricted to only symbiotic systems with a shocked red giant (RG) wind. The
lack of a free-expansion stage favors V745 Sco to have a density enhancement
around the white dwarf (WD), above that contributed by a RG wind. Our analysis
also suggests that the WD in V745 Sco is very massive and a potential
progenitor for a future SN Ia explosion.Comment: To appear in ApJ (Letters
Tight constraints on the existence of additional planets around HD 189733
We report a transit timing study of the transiting exoplanetary system HD
189733. In total we observed ten transits in 2006 and 2008 with the 2.6-m
Nordic Optical Telescope, and two transits in 2007 with the 4.2-m William
Herschel Telescope. We used Markov-Chain Monte Carlo simulations to derive the
system parameters and their uncertainties, and our results are in a good
agreement with previously published values. We performed two independent
analyses of transit timing residuals to place upper mass limits on putative
perturbing planets. The results show no evidence for the presence of planets
down to 1 Earth mass near the 1:2 and 2:1 resonance orbits, and planets down to
2.2 Earth masses near the 3:5 and 5:3 resonance orbits with HD 189733b. These
are the strongest limits to date on the presence of other planets in this
system.Comment: 10 pages, 4 figures, accepted by MNRA
A possible disk mechanism for the 23d QPO in Mkn~501
Optically thin two-temperature accretion flows may be thermally and viscously
stable, but acoustically unstable. Here we propose that the O-mode instability
of a cooling-dominated optically thin two-temperature inner disk may explain
the 23-day quasi-periodic oscillation (QPO) period observed in the TeV and
X-ray light curves of Mkn~501 during its 1997 high state. In our model the
relativistic jet electrons Compton upscatter the disk soft X-ray photons to TeV
energies, so that the instability-driven X-ray periodicity will lead to a
corresponding quasi-periodicity in the TeV light curve and produce correlated
variability. We analyse the dependence of the instability-driven
quasi-periodicity on the mass (M) of the central black hole, the accretion rate
() and the viscous parameter () of the inner disk. We
show that in the case of Mkn~501 the first two parameters are constrained by
various observational results, so that for the instability occurring within a
two-temperature disk where , the quasi-period is expected to
lie within the range of 8 to 100 days, as indeed the case. In particular, for
the observed 23-day QPO period our model implies a viscosity coefficient
, a sub-Eddington accretion rate and a transition radius to the outer standard disk of , and predicts a period variation due to the
motion of the instability region.Comment: 18 pages, 1 figure, accepted by AP
Wigner delay time from a random passive and active medium
We consider the scattering of electron by a one-dimensional random potential
(both passive and active medium) and numerically obtain the probability
distribution of Wigner delay time (). We show that in a passive medium
our probability distribution agrees with the earlier analytical results based
on random phase approximation. We have extended our study to the strong
disorder limit, where random phase approximation breaks down. The delay time
distribution exhibits the long time tail () due to resonant states,
which is independent of the nature of disorder indicating the universality of
the tail of the delay time distribution. In the presence of coherent absorption
(active medium) we show that the long time tail is suppressed exponentially due
to the fact that the particles whose trajectories traverse long distances in
the medium are absorbed and are unlikely to be reflected.Comment: 13 pages RevTex, 5 EPS figures included, communicated to PR
Proceedings of the 4th International Conference on Innovations in Automation and Mechatronics Engineering (ICIAME2018)
The Mechatronics Department (Accredited by National Board of Accreditation, New Delhi, India) of the G H Patel College of Engineering and Technology, Gujarat, India arranged the 4th International Conference on Innovations in Automation and Mechatronics Engineering 2018, (ICIAME 2018) on 2-3 February 2018. The papers presented during the conference were based on Automation, Optimization, Computer Aided Design and Manufacturing, Nanotechnology, Solar Energy etc and are featured in this book
Existence and Uniqueness of Tri-tronqu\'ee Solutions of the second Painlev\'e hierarchy
The first five classical Painlev\'e equations are known to have solutions
described by divergent asymptotic power series near infinity. Here we prove
that such solutions also exist for the infinite hierarchy of equations
associated with the second Painlev\'e equation. Moreover we prove that these
are unique in certain sectors near infinity.Comment: 13 pages, Late
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