434 research outputs found

    New Classes of Univariate Continuous Exponential Power Series Distributions

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    Recently, many researchers have developed various classes of continuous probability distributions which can be generated via the generalized Pearson differential equation and other techniques. In this paper, motivated by the importance of the power series in probability theory and its applications, we derive some new classes of univariate exponential power series distributions for a realvalued continuous random variable, which we call exponential power series distributions. Various mathematical properties of the proposed classes of distributions are discussed. Based on these distributional properties, we have established some characterizations of these distributions as well. It is hoped that the findings of the paper will be useful for researchers in the fields of probability, statistics and other applied sciences

    Simple aquaculture training for rural development in Zimbabwe

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    A summary is provided of a course introduced in 1987 at the Chaminuka Training Centre in Zimbabwe for training in rural aquaculture. The recruitment of trainees, aquaculture and rural development, the curriculum and practical training are outlined

    Investigation of In vitro Release Kinetics of Carbamazepine from Eudragit® RS PO and RL PO Matrix Tablets

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    Purpose: The objective of this research work was to prepare and evaluate the effect of Eudragit RS PO and Eudragit RL PO polymers on the physical property and release characteristics of carbamazepine matrix tablets.Methods: Matrix tablets containing carbamazepine were prepared with Eudragit® RS PO alone as the rate-retarding polymer (coded batch series ‘A’) and also with a combination of Eudragit® RS PO and RL PO (coded batch series ‘B’). The tablets were characterized for hardness as well as for carbamazepine release. The release data were subjected to differentmodels in order to evaluate their release kinetics and mechanisms.Results: The hardness of batch series ‘A’ matrix tablet was >160 kg/cm2 while for batch series ‘B’, it was >170 kg/cm2. Carbamazepine tablets containing only Eudragit RS PO showed very slow release (less than 6% in 8 h) but when Eudragit RL PO was blended with Eudragit RS PO, the release rate improved significantly to 44% in 24 h (p < 0.05). Drug release mechanism was a complex mixture of diffusion and erosion.Conclusion: Carbamazepine matrix tablets of satisfactory hardness were produced. Furthermore, by blending Eudragit RS PO with Eudragit RL PO in the matrix, tablets of varying release characteristics can be prepared

    Evaluating the ecological and social targeting of a compensation scheme in Bangladesh.

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    Conservation payments are increasingly advocated as a way to meet both social and ecological objectives, particularly in developing countries, but these payments often fail to reach the 'right' individuals. The Government of Bangladesh runs a food compensation scheme that aims to contribute to hilsa (Tenualosa ilisha) conservation by improving the socioeconomic situation of households affected by hilsa sanctuary fishing bans. Analysing data from a household survey of compensation recipients and non-recipients, we identify the current correlates of compensation distribution and explore perceptions of fairness in this distribution. We find that distribution is largely spatial rather than based on the household characteristics that are supposed to determine eligibility for compensation, indicating political influence in the distribution process. We also find the compensation scheme is widely perceived to be unfair, which could be undermining its potential to compensate vulnerable fishers while improving compliance with fishing bans. The spatial distribution of compensation would shift substantially under alternative targeting scenarios that are likely to improve the cost-effectiveness of the scheme, such as targeting those who are most dependent on fishing for their livelihood. This study highlights a challenge for conservation payment schemes that aim to achieve the dual objectives of poverty reduction and ecological sustainability, particularly large-scale public schemes, and suggests that more effective targeting and transparency about the basis of payment distribution are prerequisites for schemes to be both cost-effective and socially acceptable

    COMPARATIVE STUDY OF SURFACE ROUGHNESS CRITERIA DURING PULSED Nd:YAG LASER MICRO-TURNING OF ALUMINA CERAMIC AT LASER FOCUSED AND DEFOCUSED CONDITIONS

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    Abstract Laser micromachining technology finds great potentials for successful application in the area of high precision micro-engineering. Laser micro-turning process is one of the new and emerging technologies in the area of laser material processing (LMP) of engineering materials. Laser micro-turning process is one of the latest promising laser material processing techniques which can be employed for generation of micro-turning surface of particular surface profile and dimensional accuracy on cylindrical workpiece. The present paper addresses the laser micro-turning process of cylindrical shaped 99% pure aluminium oxide (Al 2 O 3 ) ceramics of size 10 mm in diameter and 40 mm in length. The experiments have been conducted utilizing one factor at a time (OFAT) experimental scheme. The targated depth was set at 100 µm. Laser average power, pulse frequency, workpiece rotating speed and Y feed rate were considered as process variables. After each experiment, surface roughness (Ra and Rt) has been measured. An attempt has been made for comparative study and analyse the effect of focused and defocused conditions of laser beam on surface roughness criteria of laser micro-turning surface. From the experimental results, it was revealed that both surface roughness, Ra and Rt, are less at all defocusing conditions of laser beam compared with focusing condition of beam. However, other process parameters have significant effects on surface roughness criteria at both the focused and defocused conditions. Optical and SEM micrographs of the laser turned surface have also been studied comparatively to examine the quality of machined surface at various parametric settings and focusing conditions

    Energy management and sizing of a stand-alone hybrid renewable energy system for community electricity, fresh water, and cooking gas demands of a remote island

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    Research into the off-grid hybrid energy system to provide reliable electricity to a remote community has extensively been done. However, simultaneous meeting electric, freshwater, and gas demands from the off-grid hybrid energy sources are very scarce in literature. Power- to-X (PtX) is gaining attention in recent days in the energy transition scenarios to generate green hydrogen, the primary product of the process as an energy carrier, which is deemed to replace conventional fuels to reach absolute carbon neutrality. In this study, renewable–based hybrid energy is developed to simultaneously meet the electricity, freshwater, and gas (cooking gas via methanation process) demands for a remote Island in Bangladesh. In this process, an energy management strategy has been developed to use the excess energy to generate both freshwater and the hydrogen, where hydrogen is then converted to natural gas via methanation process. The PV, wind turbine, diesel generator, battery, and fuel cell have been optimized using non-dominating sorting algorithm-II (NSGA-II) to offer reliable, cost-effective solutions of electricity, freshwater, and cooking gas for the end users. Results reported that the PV/WT/DG/Batt configuration has been found the most economic configuration with the lowest COE (0.1724 /kWh)whichis9/kWh) which is 9 % lower than PV/WT/Batt configuration which has the second lowest COE. The cost of water (COW) and cost of gas (COG) of the PV/WT/DG/Batt system are also the lowest among all the four configurations and have been found 1.185 /m3 and 3.978 $/m3, respectively

    Pattern of dyslipidemia in hypothyroid patients: A cross sectional study

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    Background: An association between thyroid dysfunction and dyslipidemia prevails. Levels of total cholesterol, low density lipoprotein cholesterol, triglycerides tend to increase as thyroid function declines.Objective: To find out the pattern of dyslipidemia in hypothyroid patients. Methods: Sixty cases were selected as a sample of convenience in this cross sectional study from in-patienl depa1tment of Medicine and Endocrinology, BSMMU. Meticulous history taking and thorough clinical examinations were done. Report of lipid profile and thyroid function tests were recorded from patients file. All the information's were recorded in a pre-designed sttuctured questionnaire. Collected data were classi­fied, edited, coded and entered into the computer for statistical analysis by using SPSS. Results: Among the 60 cases, 43 (72%) were female; 17(28%) were male. Age range was 24-59 years with a mean age of 38.80 (± I 0.35) years. Majority 38(65%) were housewife, followed by service holder 11(18.33%), 08(13.3%) were business men and 02(3.3%) had other occupations. Majority 42(70%) patients were taking thyroxin. Mean Total cholesterol (TC), LDL cholesterol, Triglycer­ide (TG) and HDL were 222.20(±42.25); 138.63(±31.51); 243.36(±83.13) and 37.30(±5.12) respectably. Conclusion: All hypothyroid subjects had dyslipidemia. The present study indicated that hypothyroidism was associated with an abnormal lipid profile, especially with respect to the levels of total cholesterol and triglyceride

    Culture feasibility of African catfish ( Clarias gariepinus lin.) fry in glass tank and synthetic hapa system using supplemental diets

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    Abstract An experiment was carried out with 1 0 days old Clarias gariepinus fry over a period of 42 days to determine the effects of different feeds on growth and survival of African catfish fry in glass tanks. The experiment was designed into four treatments each having three replications. Thus treatment 1 (T 1 ) was named as Tank Tubifex (TT) and treatment 2 (T 2 ) as Tank Sabinco (TS), treatment 3 as Pond Tubifex (PT), and treatment 4 (T 4 ) as Pond Sabinco (PS). Live Tubifex (protein levels 64.48%) was supplied to treatments 1 and 3 and rest of the treatments were supplied Sabinco starter-1 (protein levels 40.13%). The highest and the lowest growth in total length and weight were 12.90 em, 18.77 g and 6.17 em, 4.04 g recorded from the treatments 3 and 2, respectively. Growth of catfish fry under treatment 3 in terms of both length and weight were significantly higher (P&lt;0.01) than those of the other treatments. However treatment 2 showed the significantly lowest (P&lt;0.01) growth performance among the various treatments. The highest survival rate (92%) was also obtained with treatment 3. Tubifex proved to be the best larval feed in respect of growth and survival rate

    Pattern of dyslipidemia in hypothyroid patients: A cross sectional study

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    Background: An association between thyroid dysfunction and dyslipidemia prevails. Levels of total cholesterol, low density lipoprotein cholesterol, triglycerides tend to increase as thyroid function declines. Objective: To find out the pattern of dyslipidemia in hypothyroid patients. Methods: Sixty cases were selected as a sample of convenience in this cross sectional study from in-patienl depa1tment of Medicine and Endocrinology, BSMMU. Meticulous history taking and thorough clinical examinations were done. Report of lipid profile and thyroid function tests were recorded from patients file. All the information's were recorded in a pre-designed sttuctured questionnaire. Collected data were classi­fied, edited, coded and entered into the computer for statistical analysis by using SPSS. Results: Among the 60 cases, 43 (72%) were female; 17(28%) were male. Age range was 24-59 years with a mean age of 38.80 (± I 0.35) years. Majority 38(65%) were housewife, followed by service holder 11(18.33%), 08(13.3%) were business men and 02(3.3%) had other occupations. Majority 42(70%) patients were taking thyroxin. Mean Total cholesterol (TC), LDL cholesterol, Triglycer­ide (TG) and HDL were 222.20(±42.25); 138.63(±31.51); 243.36(±83.13) and 37.30(±5.12) respectably. Conclusion: All hypothyroid subjects had dyslipidemia. The present study indicated that hypothyroidism was associated with an abnormal lipid profile, especially with respect to the levels of total cholesterol and triglyceride

    A Score-Driven Conditional Correlation Model for Noisy and Asynchronous Data: An Application to High-Frequency Covariance Dynamics

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    The analysis of the intraday dynamics of covariances among high-frequency returns is challenging due to asynchronous trading and market microstructure noise. Both effects lead to significant data reduction and may severely affect the estimation of the covariances if traditional methods for low-frequency data are employed. We propose to model intraday log-prices through a multivariate local-level model with score-driven covariance matrices and to treat asynchronicity as a missing value problem. The main advantages of this approach are: (i) all available data are used when filtering the covariances, (ii) market microstructure noise is taken into account, (iii) estimation is performed by standard maximum likelihood. Our empirical analysis, performed on 1-sec NYSE data, shows that opening hours are dominated by idiosyncratic risk and that a market factor progressively emerges in the second part of the day. The method can be used as a nowcasting tool for high-frequency data, allowing to study the real-time response of covariances to macro-news announcements and to build intraday portfolios with very short optimization horizons
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