16,837 research outputs found

    Byssoloma subdiscordans (Nyl.) P. James: Distributional range and its habitat preference in Indian subcontinent

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    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)

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    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

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    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 kms1^{-1} plowing into its surrounding environment. The temperature of the shocked gas is raised to a high value exceeding 108^{8}K 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 γ\gamma ray generation. V745 Sco is the latest nova, apart from five other known novae, to show γ\gamma ray emission. It may be an important testbed to resolve the crucial question whether all novae are generically γ\gamma ray emitters by virtue of having a circumbinary reservoir of material that is shocked by the ejecta rather than γ\gamma 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

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    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

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    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 (M˙\rm{\dot{M}}) and the viscous parameter (α\alpha) 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 α=0.051.0\alpha=0.05-1.0, 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 α0.28\alpha \leq 0.28, a sub-Eddington accretion rate M˙0.02M˙Edd\dot{M} \simeq 0.02 \dot{M}_{\rm Edd} and a transition radius to the outer standard disk of r060rgr_0 \sim 60 r_g, and predicts a period variation δP/P0.23\delta P/P \sim 0.23 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

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    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 (τ\tau). 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 (1/τ21/\tau^2) 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)

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    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

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    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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