1,570 research outputs found
Abnormal Returns and Quarterly Earnings Announcements: A Study on BSE 500 Group of Companies
The release of information has an impact on stocks in the market. The release of information process leads toward a shift in either the volume or the price as the release of information causes the old equilibrium level to shift to a new equilibrium as it tries to adjust to the new information
EFFECT OF DIFFERENT SOLVENTS ON ANTIOXIDANT ACTIVITY OF LEAF EXTRACTS OF CALOTROPIS PROCERA AND AZADIRACHTA INDICA
Objective: This study was performed to identify the phytochemicals and comparatively evaluate the antioxidant activity of Calotropis procera and Azadirachta indica by detection of total phenolics, hydrogen peroxide radical scavenging activity, and estimation of condensed tannins in different solvent systems and at different temperatures.Methods: Leaves of C. procera and A. indica were extracted in water, methanol by soaking dried leaf powder at room temperature and also by boiling the leaf powder in water for 30 minutes. Phytochemical tests were performed in all of the extracts. The antioxidant activity was determined by hydrogen peroxide radical scavenging activity. Quantitative estimation of total phenolics and hydrolysable tannins was also performed.Results: The total phenolics in both leaf extracts was obtained maximum in boiled extract (40.7±1.20 mg gallic acid equivalent [GAE]/g dry extract in C. procera and 33.66±1.45 mg GAE/g dry extract in A. indica). The amount of hydrolysable tannins in both leaf extracts was found to be highest in methanol (150±1.88 mg catechin equivalent/g dry extract in C. procera and 144.8±2.63 mg catechin equivalent/g dry extract in A. indica).Conclusion: The study showed promising results indicating that these plants are a good source of antioxidants. The majority of phytochemicals were extracted in distilled water and methanol acts as a good solvent for extraction of tannins, whereas an increase in temperature leads to poor extraction of tannins.Keywords: Antioxidant, Phytochemicals, Phenolics, Radical, Tannins
Kernel Density Estimator Methods for Monte Carlo Radiation Transport.
In this dissertation, the Kernel Density Estimator (KDE), a nonparametric probability density estimator, is studied and used to represent global Monte Carlo (MC) tallies. KDE is also employed to remove the singularities from two important Monte Carlo tallies, namely point detector and surface crossing flux tallies. Finally, KDE is also applied to accelerate the Monte Carlo fission source iteration for criticality problems.
In the conventional MC calculation histograms are used to represent global tallies which divide the phase space into multiple bins. Partitioning the phase space into bins can add significant overhead to the MC simulation and the histogram provides only a first order approximation to the underlying distribution. The KDE method is attractive because it can estimate MC tallies in any location within the required domain without any particular bin structure. The quantitative and numerical convergence properties of KDE tallies are also investigated.
Monte Carlo point detector and surface crossing flux tallies are two widely used tallies but they suffer from an unbounded variance. As a result, the central limit theorem can not be used for these tallies to estimate confidence intervals. By construction, KDE tallies can be directly used to estimate flux at a point but the variance of this point estimate does not converge as 1/N, which is not unexpected for a point quantity. However, an improved approach is to modify both point detector and surface crossing flux tallies directly by using KDE within a variance reduction approach by taking advantage of the fact that KDE estimates the underlying probability density function. This methodology is demonstrated by several numerical examples.
KDE is also applied to Monte Carlo eigenvalue calculations for nuclear reactor analyses. KDE is used to estimate the fission source distribution at the end of each generation and realizations from the estimated source distribution are used as the starting locations for the next generation. The source convergence is measured by the relative source entropy. Significant source convergence improvement is observed for the proposed KDE method compared to the conventional Monte Carlo fission source iteration.Ph.D.Nuclear Engineering & Radiological SciencesUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/75844/1/bkaushik_1.pd
Why children are not vaccinated: a review of the grey literature
SummaryIn collaboration with WHO, IMMUNIZATIONbasics analyzed 126 documents from the global grey literature to identify reasons why eligible children had incomplete or no vaccinations.The main reasons for under-vaccination were related to immunization services and to parental knowledge and attitudes. The most frequently cited factors were: access to services, health staff attitudes and practices, reliability of services, false contraindications, parents’ practical knowledge of vaccination, fear of side effects, conflicting priorities and parental beliefs. Some family demographic characteristics were strong, but underlying, risk factors for under-vaccination.Studies must be well designed to capture a complete picture of the simultaneous causes of under-vaccination and to avoid biased results. Although the grey literature contains studies of varying quality, it includes many well-designed studies.Every immunization program should strive to provide quality services that are accessible, convenient, reliable, friendly, affordable and acceptable, and should solicit feedback from families and community leaders. Every program should monitor missed and under-vaccinated children and assess and address the causes. Although global reviews, such as this one, can play a useful role in identifying key questions for local study, local enquiry and follow-up remain essential
Extreme Levels of Underweight and Stunting Among Pre-Adolescent Children of Low Socioeconomic Class from Madhyamgram and Barasat, West Bengal, India
A cross-sectional study on 1206 children (788 boys, 618 girls) aged 1–12 years, belonging to low socioeconomic status,
of Barasat and Madhyamgram, West Bengal, India, was undertaken to investigate age and sex variations in height and
weight. It also evaluated the levels of underweight and stunting among them. Anthropometric measurements included
weight and height. Weight-for-age (WA) and height-for-age (HA) <–2 z-scores were used to evaluate underweight (UW)
and stunting (ST), respectively, following the National Center for Health Statistics (NCHS) Guidelines. Results showed
that boys aged 4 and 11 years were significantly heavier than girls of corresponding ages. Boys aged 7 years were significantly
taller than girls of the same age. Significant (p<0.001) age differences existed in mean weight and height in boys
(weight: F=336.762; height: F=565.160) as well as girls (weight: F=275.320; height =498.715). Results also revealed
that the mean z-scores of WA (WAZ) and HA (HAZ) were less than (negative values) those of NCHS for both sexes at all
ages. The overall (age combined) rate of UW was 60.4% and 51.3%; while that of ST was 51.7% and 48.4%, in boys and
girls, respectively. Based on World Health Organization classification of severity of malnutrition, the prevalence of UW
and ST were very high (30%) in both sexes. In conclusion, this study demonstrated that the prevalence of UW and ST
were very high among the subjects. Since the nutritional status of the subjects is not satisfactory, there is need for immediate
supplementary nutrition
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