283 research outputs found

    AstroSat view of MAXI J1535-571: broadband spectro-temporal features

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    We present the results of Target of Opportunity (ToO) observations made with AstroSat of the newly discovered black hole binary MAXI J1535-571. We detect prominent C-type Quasi-periodic Oscillations (QPOs) of frequencies varying from 1.85 Hz to 2.88 Hz, along with distinct harmonics in all the AstroSat observations. We note that while the fundamental QPO is seen in the 3 - 50 keV energy band, the harmonic is not significant above ~ 35 keV. The AstroSat observations were made in the hard intermediate state, as seen from state transitions observed by MAXI and Swift. We attempt spectral modelling of the broadband data (0.7-80 keV) provided by AstroSat using phenomenological and physical models. The spectral modelling using nthComp gives a photon index in the range between 2.18-2.37 and electron temperature ranging from 21 to 63 keV. The seed photon temperature is within 0.19 to 0.29 keV. The high flux in 0.3 - 80 keV band corresponds to a luminosity varying from 0.7 to 1.07 L_Edd assuming the source to be at a distance of 8 kpc and hosting a black hole with a mass of 6 M_{\odot}. The physical model based on the two-component accretion flow gives disc accretion rates as high as ~ 1 m˙Edd\dot{m}_{Edd} and halo rate ~ 0.2 m˙Edd\dot{m}_{Edd} respectively. The near Eddington accretion rate seems to be the main reason for the unprecedented high flux observed from this source. The two-component spectral fitting of AstroSat data also provides an estimate of a black hole mass between 5.14 to 7.83 M_{\odot}.Comment: 15 pages, 9 figures, MNRAS (Accepted on 2019 May 10

    Nonleptonic two-body charmless B decays involving a tensor meson in ISGW2 model

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    Nonleptonic charmless B decays into a pseudoscalar (P) or a vector (V) meson accompanying a tensor (T) meson are re-analyzed. We scrutinize the hadronic uncertainties and ambiguities of the form factors which appear in the literature. The Isgur-Scora-Grinstein-Wise updated model (ISGW2) is adopted to evaluate the relevant hadronic matrix elements. We calculate the branching ratios and CP asymmetries for various BP(V)TB\to P(V)T decay processes. With the ISGW2 model, the branching ratios are enhanced by about an order of magnitude compared to the previous estimates. We show that the ratios \calB(B\to VT)/\calB(B\to PT) for some strangeness-changing processes are very sensitive to the CKM angle γ\gamma (ϕ3\phi_3).Comment: 23 pages, REVTEX; minor clarifications included; to appear in Phys. Rev.

    Hadronic decays of B involving a tensor meson through a bcb \to c transition

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    We re-analyze hadronic decays of B mesons to a pseudoscalar (P) and a tensor meson (T), or a vector meson (V) and a tensor meson, through a bcb \to c transition. We discuss possible large uncertainties to branching ratios (BR's) of the relevant modes, mainly arising from uncertainties to the hadronic form factors for the BTB \to T transition. The BR's and CP asymmetries for BPTB \to PT and VT decays are then calculated by using the form factors given in the ISGW2 model (the improved version of the original Isgur-Scora-Grinstein-Wise (ISGW) model). We find that the estimated BR's of many modes are increased by an order of magnitude, compared to the previous results calculated within the ISGW model.Comment: 22 pages, LaTex; minor clarifications included; to appear in Phys. Rev.

    Hadronic B Decays Involving Even Parity Charmed Mesons

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    Hadronic B decays containing an parity-even charmed meson in the final state are studied. Specifically we focus on the Cabibbo-allowed decays BˉDπ(ρ),DDˉs(),DˉsD()\bar B\to D^{**} \pi(\rho), D^{**}\bar D_s^{(*)}, \bar D^{**}_sD^{(*)} and BˉsDsπ(ρ)\bar B_s\to D_s^{**}\pi(\rho), where DD^{**} denotes generically a p-wave charmed meson. The BDB\to D^{**} transition form factors are studied in the improved version of the Isgur-Scora-Grinstein-Wise quark model. We apply heavy quark effective theory and chiral symmetry to study the strong decays of p-wave charmed mesons and determine the magnitude of the D11/2D13/2D_1^{1/2}-D_1^{3/2} mixing angle. Except the decay to D1(2427)0πD_1(2427)^0\pi^- the predictions for BD0πB^-\to D^{**0}\pi^- agree with experiment. The sign of D11/2D13/2D_1^{1/2}-D_1^{3/2} mixing angle is found to be positive in order to avoid a severe suppression on the production of D1(2427)0πD_1(2427)^0\pi^-. The interference between color-allowed and color-suppressed tree amplitudes is expected to be destructive in the decay BD1(2427)0πB^-\to D_1(2427)^0\pi^-. Hence, an observation of the ratio D1(2427)0π/D1(2427)+πD_1(2427)^0\pi^-/D_1(2427)^+\pi^- can be used to test the relative signs of various form factors as implied by heavy quark symmetry. Although the predicted BD1(2420)0ρB^-\to D_1(2420)^0\rho^- at the level of 3×1033\times 10^{-3} exceeds the present upper limit, it leads to the ratio D1(2420)ρ/D1(2420)π2.6D_1(2420)\rho^-/D_1(2420)\pi^-\approx 2.6 as expected from the factorization approach and from the ratio fρ/fπ1.6f_\rho/f_\pi\approx 1.6 . Therefore, it is crucial to have a measurement of this mode to test the factorization hypothesis. For BˉDˉsD\bar B\to \bar D_s^{**}D decays, it is expected that \bar D_{s0}^*D\gsim \bar D_{s1}D as the decay constants of the multiplet (Ds0,Ds1)(D_{s0}^*,D_{s1}) become the same in the heavy quark limit.Comment: 27 pages, Belle's new data on DD_s^{**} productions in B decays and on the radiative decay D_{s1}-> D_s\gamma are updated and discussed. Add two reference

    Family-led rehabilitation after stroke in India (ATTEND): a randomised controlled trial

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    Background: Most people with stroke in India have no access to organised rehabilitation services. The effectiveness of training family members to provide stroke rehabilitation is uncertain. Our primary objective was to determine whether family-led stroke rehabilitation, initiated in hospital and continued at home, would be superior to usual care in a low-resource setting. Methods: The Family-led Rehabilitation after Stroke in India (ATTEND) trial was a prospectively randomised open trial with blinded endpoint done across 14 hospitals in India. Patients aged 18 years or older who had had a stroke within the past month, had residual disability and reasonable expectation of survival, and who had an informal family-nominated caregiver were randomly assigned to intervention or usual care by site coordinators using a secure web-based system with minimisation by site and stroke severity. The family members of participants in the intervention group received additional structured rehabilitation training—including information provision, joint goal setting, carer training, and task-specific training—that was started in hospital and continued at home for up to 2 months. The primary outcome was death or dependency at 6 months, defined by scores 3–6 on the modified Rankin scale (range, 0 [no symptoms] to 6 [death]) as assessed by masked observers. Analyses were by intention to treat. This trial is registered with Clinical Trials Registry-India (CTRI/2013/04/003557), Australian New Zealand Clinical Trials Registry (ACTRN12613000078752), and Universal Trial Number (U1111-1138-6707). Findings: Between Jan 13, 2014, and Feb 12, 2016, 1250 patients were randomly assigned to intervention (n=623) or control (n=627) groups. 33 patients were lost to follow-up (14 intervention, 19 control) and five patients withdrew (two intervention, three control). At 6 months, 285 (47%) of 607 patients in the intervention group and 287 (47%) of 605 controls were dead or dependent (odds ratio 0·98, 95% CI 0·78–1·23, p=0·87). 72 (12%) patients in the intervention group and 86 (14%) in the control group died (p=0·27), and we observed no difference in rehospitalisation (89 [14%]patients in the intervention group vs 82 [13%] in the control group; p=0·56). We also found no difference in total non-fatal events (112 events in 82 [13%] intervention patients vs 110 events in 79 [13%] control patients; p=0·80). Interpretation: Although task shifting is an attractive solution for health-care sustainability, our results do not support investment in new stroke rehabilitation services that shift tasks to family caregivers, unless new evidence emerges. A future avenue of research should be to investigate the effects of task shifting to health-care assistants or team-based community care. Funding: The National Health and Medical Research Council of Australia

    EMERGING QUALITY CONTROL PERSPECTIVES FOR AYURVEDIC DRUG

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    Ayush system of medicines based Herbal Pharmaceutical industry (ASU & H drug mfg) is having great potential and opportunities in India for development in future because of global acceptability of the medicinal plants & their value added products in Domestic & International Market as Ayurvedic, Unani and Siddha medicines, Herbal Nutraceuticals, Herbal Cosmoceutical, Herbal Health drinks, Dietary Health Supplements, Medicinal Plants / Crude Drugs, Herbal Extracts / Concentrates, Veterinary Medicines, Health Foods. India is rich with 771468 registered Ayush practitioners, 8667 licensed Ayurvedic drug manufacturing units. Quality Control/Assurance is the department, which controls all activities at various level of manufacturing as National & International standard. Ministry of Ayush continues to lay emphasis on up gradation of AYUSH educational standards, Quality control and standardisation of drugs, improving the availability of medicinal plant material, research and development and awareness generation about the efficacy of the system domestically and internationally. There are various issues & challenges related to drug quality for ASU&H Pharmaceutical Industries in India. It needs proper attention of policy makers and regulator & academia. Complete Implementation of GMP (schedule T) norm/guidelines and quality control/assurance procedure and activities is a big challenge for ensuring quality of drug
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