118 research outputs found

    Effect of Na Substitution on Rare-Earth Manganites

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    An effort is made to study the effect of alkali metal substitution in particular Na, on the rare earth side of manganites of La, Nd and Pr. The samples are prepared by wet-chemical route known as Pyrophoric method. The structural characterization of the samples is carried out through detail Reitveld analysis of the XRD data which shows all the samples are single phase and stoichiometric. The granular information and sizes is probed through the SEM analysis. The star like structures of the material is the unique features of samples in the vicinity of the nano order. However the transport properties are unique among the separate constituents of the Na and rare earth combinations starting from pure insulator to metal-insulator transition

    Investigation on superior performance by fractional controller for cart-servo laboratory set-up

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    In this paper, an investigation is made on the superiority of fractional PID controller (PI^alpha D^beta) over conventional PID for the cart-servo laboratory set-up. The designed controllers are optimum in the sense of Integral Absolute Error (IAE) and Integral Square Error (ISE). The paper contributes in three aspects: 1) Acquiring nonlinear mathematical model for the cart-servo laboratory set-up, 2) Designing fractional and integer order PID for minimizing IAE, ISE, 3) Analyzing the performance of designed controllers for simulated plant model as well as real plant. The results show a significantly superior performance by PI^alpha D^beta as compared to the conventional PID controller

    Development of a perfect prognosis probabilistic model for prediction of lightning over south-east India

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    A prediction model based on the perfect prognosis method was developed to predict the probability of lightning and probable time of its occurrence over the south-east Indian region. In the perfect prognosis method, statistical relationships are established using past observed data. For real time applications, the predictors are derived from a numerical weather prediction model. In the present study, we have developed the statistical model based on Binary Logistic Regression technique. For developing the statistical model, 115 cases of lightning that occurred over the south-east Indian region during the period 2006–2009 were considered. The probability of lightning (yes or no) occurring during the 12-hour period 0900–2100 UTC over the region was considered as the predictand. The thermodynamic and dynamic variables derived from the NCEP Final Analysis were used as the predictors. A three-stage strategy based on Spearman Rank Correlation, Cumulative Probability Distribution and Principal Component Analysis was used to objectively select the model predictors from a pool of 61 potential predictors considered for the analysis. The final list of six predictors used in the model consists of the parameters representing atmospheric instability, total moisture content in the atmosphere, low level moisture convergence and lower tropospheric temperature advection. For the independent verifications, the probabilistic model was tested for 92 days during the months of May, June and August 2010. The six predictors were derived from the 24-h predictions using a high resolution Weather Research and Forecasting model initialized with 00 UTC conditions. During the independent period, the probabilistic model showed a probability of detection of 77% with a false alarm rate of 35%. The Brier Skill Score during the independent period was 0.233, suggesting that the prediction scheme is skillful in predicting the lightning probability over the south-east region with a reasonable accuracy

    Sensitivity of WRF cloud microphysics to simulations of a severe thunderstorm event over southeast India

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    In the present study, we have used the Weather Research and Forecasting (WRF) model to simulate the features associated with a severe thunderstorm observed over Gadanki (13.5° N, 79.2° E), over southeast India, on 21 May 2008 and examined its sensitivity to four different microphysical (MP) schemes (Thompson, Lin, WSM6 and Morrison). We have used the WRF model with three nested domains with the innermost domain of 2 km grid spacing with explicit convection. The model was integrated for 36 h with the GFS initial conditions of 00:00 UTC, 21 May 2008. For validating simulated features of the thunderstorm, we have considered the vertical wind measurements made by the Indian MST radar installed at Gadanki, reflectivity profiles by the Doppler Weather Radar at Chennai, and automatic weather station data at Gadanki.There are major differences in the simulations of the thunderstorm among the MP schemes, in spite of using the same initial and boundary conditions and model configuration. First of all, all the four schemes simulated severe convection over Gadanki almost an hour before the observed storm. The DWR data suggested passage of two convective cores over Gadanki on 21 May, which was simulated by the model in all the four MP schemes. Comparatively, the Thompson scheme simulated the observed features of the updraft/downdraft cores reasonably well. However, all the four schemes underestimated strength and vertical extend of the updraft cores. The MP schemes also showed problems in simulating the downdrafts associated with the storm. While the Thompson scheme simulated surface rainfall distribution closer to observations, the other three schemes overestimated observed rainfall. However, all the four MP schemes simulated the surface wind variations associated with the thunderstorm reasonably well. The model simulated reflectivity profiles were consistent with the observed reflectivity profile, showing two convective cores. These features are consistent with the simulated condensate profiles, which peaked around 5-6 km. As the results are dependent on initial conditions, in simulations with different initial conditions, different schemes may become closer to observations. The present study suggests not only large sensitivity but also variability of the microphysical schemes in the simulations of the thunderstorm. The study also emphasizes the need for a comprehensive observational campaign using multi-observational platforms to improve the parameterization of the cloud microphysics and land surface processes over the Indian region

    COMPARISON OF POST-LICENSURE SAFETY SURVEILLANCE OF BIVALENT AND QUADRIVALENT HUMAN PAPILLOMAVIRUS VACCINES IN HEALTHY MUMBAI WOMEN

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    Objective: This study is the first comprehensive effort after HPV vaccine controversy in INDIA to compare two HPV vaccines without vaccine manufacturers funding in single, randomized, well-defined population of healthy married women aged 18-25 years using identical methodology for assessment.Methods: The study protocol was approved by an institutional ethical review committee and registered in Clinical trial registry of INDIA prior to subject recruitment. Total 77 women were screened but 69 were randomized to receive either HPV2 or HPV4 vaccines.Results: According to the present study, both HPV vaccines were well tolerated without any serious vaccine-related adverse event. Adverse drug reactions reported for both HPV vaccinations were 22 (35.48%) after the ï¬rst dose, 7 (12.05%) after the second dose and 11 (25%) after the third dose. After bivalent and quadrivalent HPV vaccination, 29 and 11 adverse drug events were recorded within seven days after any HPV vaccine dose respectively. Most frequently reported solicited local symptom from both groups was34 injection site pain which was mild in intensity.Conclusion: Both HPV vaccines appear to be safe, HPV4 being more cost-effective. However, large scale post-marketing studies are needed in view of amount of disease burden.Â

    Study of atmospheric forcing and responses (SAFAR) campaign: overview

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    Study of Atmospheric Forcing and Responses (SAFAR) is a five year (2009-2014) research programme specifically to address the responses of the earth's atmosphere to both natural and anthropogenic forcings using a host of collocated instruments operational at the National Atmospheric Research Laboratory, Gadanki (13.5° N, 79.2° E), India from a unified viewpoint of studying the vertical coupling between the forcings and responses from surface layer to the ionosphere. As a prelude to the main program a pilot campaign was conducted at Gadanki during May-November 2008 using collocated observations from the MST radar, Rayleigh lidar, GPS balloonsonde, and instruments measuring aerosol, radiation and precipitation, and supporting satellite data. We show the importance of the large radiative heating caused by absorption of solar radiation by soot particles in the lower atmosphere, the observed high vertical winds in the convective updrafts extending up to tropopause, and the difficulty in simulating the same with existing models, the upward traveling waves in the middle atmosphere coupling the lower atmosphere with the upper atmosphere, their manifestation in the mesospheric temperature structure and inversion layers, the mesopause height extending up to 100 km, and the electro-dynamical coupling between mesosphere and the ionosphere which causes irregularities in the ionospheric F-region. The purpose of this communication is not only to share the knowledge that we gained from the SAFAR pilot campaign, but also to inform the international atmospheric science community about the SAFAR program as well as to extend our invitation to join in our journey

    COVID-19 lockdown induced changes in NO2 levels across India observed by multi-satellite and surface observations

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    © Author(s) 2021. This work is distributed under the Creative Commons Attribution 4.0 License.We have estimated the spatial changes in NO 2levels over different regions of India during the COVID-19 lockdown (25 March-3 May 2020) using the satellite-based tropospheric column NO 2observed by the Ozone Monitoring Instrument (OMI) and the Tropospheric Monitoring Instrument (TROPOMI), as well as surface NO 2concentrations obtained from the Central Pollution Control Board (CPCB) monitoring network. A substantial reduction in NO 2levels was observed across India during the lockdown compared to the same period during previous business-as-usual years, except for some regions that were influenced by anomalous fires in 2020. The reduction (negative change) over the urban agglomerations was substantial (~20 %-40 %) and directly proportional to the urban size and population density. Rural regions across India also experienced lower NO 2values by ~15 %-25 %. Localised enhancements in NO 2associated with isolated emission increase scattered across India were also detected. Observed percentage changes in satellite and surface observations were consistent across most regions and cities, but the surface observations were subject to larger variability depending on their proximity to the local emission sources. Observations also indicate NO 2enhancements of up to~25%during the lockdown associated with fire emissions over the north-east of India and some parts of the central regions. In addition, the cities located near the large fire emission sources show much smaller NO 2reduction than other urban areas as the decrease at the surface was masked by enhancement in NO 2due to the transport of the fire emissions.Peer reviewedFinal Published versio

    Evaluation of Mitotic Figures and Cellular and Nuclear Morphometry of Various Histopathological Grades of Oral Squamous Cell Carcinoma: Comparative study using crystal violet and Feulgen stains

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    Objectives: The objectives of this study were to quantitatively estimate the number of mitotic figures (MFs) and evaluate the cellular and nuclear features of various histological grades of oral squamous cell carcinoma (OSCC) using Feulgen and 1% crystal violet stains. Methods: This case-control study took place at the Dr D. Y. Patil Dental College & Hospital in Mumbai, Maharashtra, India, between June and December 2016. A total of 51 samples were retrieved from the hospital archives. Of these, 15 well-differentiated, 15 moderately-differentiated and six poorly-differentiated OSCC samples formed the case group while 15 samples of normal gingival mucosa constituted the control group. Each sample was dyed using Feulgen and 1% crystal violet stains and the mitotic count, nuclear area (NA), cellular area (CA), nuclear perimeter (NP), cellular perimeter (CP) and nuclear-to-cytoplasmic (N/C) ratio was calculated using computeraided morphometry techniques. Results: The number of MFs visible per field was significantly higher in Feulgen-stained sections as compared to those stained with crystal violet (P = 0.050). In addition, the NA, NP, CA and CP values and N/C ratios of samples in the experimental group increased significantly in accordance with an increase in OSCC grade (P <0.001). Conclusion: The Feulgen stain is more reliable than 1% crystal violet in terms of the selective staining of MFs. Moreover, the findings of this study indicate that computer-based morphometric analysis is an effective tool for differentiating between various grades of OSCC. Keywords: Crystal Violet; Feulgen Stain; Mitotic Index; Image Cytometry; Squamous Cell Carcinoma; Oral Cancers
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