1,057 research outputs found

    Development and Application of Spatially Parameterized Depth Duration Frequency Model for Estimation of Design Rainfall for Oromia State, Ethiopia

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    The magnitude and frequency of extreme rainfall events are required for planning, design and operation of many hydrological and water resources projects. Design rainfall depth is often used to estimate the severity and rarity of floods in areas where flow records are not sufficient enough to warrant direct flood estimation. The design of hydraulic structures on un-gauged streams and creeks, such as bridges, culverts, spillways, water harvesting and flood defense mechanisms depends upon proper estimation of extreme rainfall events. Quantification of design rainfall is generally done by using information contained in Depth-Duration-Frequency (DDF) relationships. Depth Duration Frequency relationships are currently constructed based on at site frequency analysis of rainfall data separately for different durations. These relationships are not accurate and reliable since they depend on assumptions such as distribution selection for each duration; they require a large number of parameters, experience intensive equations and regionalization is also very poor and coarse. In this study a DDF model with gridded set of parameters is developed for estimation of point rainfall frequencies for a range of duration for any location in Oromia regional state. A DDF model was fitted to series of annual maxima and its parameters were determined by a least squares method and these parameters were interpolated and mapped on a 1km grid. The model allows for a parsimonious and efficient parameterization of DDF relationships, and its performance is shown to improve the reliability and robustness of design storm predictions as compared with those achievable by interpolating the quantile predictions of extreme rainfall data for specific durations. Moreover, design rainfall estimates found from the scaling DDF model are comparable to estimates obtained from traditional techniques; however, the scaled approach was more efficient and gives more reliable estimate compared with the observed rainfall depth at all stations

    Investigating the Scaling Properties of Extreme Rainfall Depth Series in Oromia Regional State, Ethiopia

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    Depth Duration Frequency (DDF) relationships are currently constructed based on at site frequency analysis of rainfall data separately for different durations. These relationships are not accurate and reliable since they depend on assumptions such as distribution selection for each duration; they require a large number of parameters, experience intensive equations and regionalization is also very poor and coarse. In this study, scaling properties of extreme rainfall depth series were examined to establish scaling behavior of statistical moments and quantile estimates over different durations. The annual extreme series of precipitation maxima for storm duration ranging from 0.5 to 24 hr observed at network of rain gauges sited in Oromia regional state were analyzed using an approach based on moments. The analysis investigated the statistical properties of rainfall extremes and detected that the statistics of the rainfall extremes follows a power law relation with its duration. Moreover, the variations of the distribution parameters with durations of annual maximum rainfall depth series were explored and found that the logEV1, EV1 and logistic distribution parameters exhibit a power law relationship with durations. Following the analysis, scale invariance of extreme rainfall depth series is investigated and dissipative (multiple scaling) nature of extreme rainfall depth series is considered, thus introducing a general distribution free framework to develop Depth Duration frequency (DDF) model.Keywords: Scaling Properties Depth Duration Frequency Rainfall Depth Series Multiple Scalin

    Cold chain status at immunisation centres in Ethiopia

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    Background: Child immunisation is among the most cost-effective ways of preventing premature child deaths, and the potency of vaccines, crucial for vaccine efficacy, is dependent on effective management of the cold chain at all levels of vaccine handling.Objective: To assess the status of the cold chain at peripheral vaccine stores in Ethiopia.Design: Institution based cross-sectional survey in two rural and one urban administrative areas were included in the study. Sixty seven health institutions providing static vaccination services were included in the study but cold chain system was assessed fully in only sixty four.Data were collected by interviewing health workers and by directly observing the cold chain equipment and records using structured forms.Results: Conditions of the cold chain system were described based on 64 of the 67 centres visited, three were excluded because of non-functioning cold chain. Complete temperature record was observed in 37(57.8%) of the centres. Thermometer was not available in four(6.3%) and thermometer reading was found to be outside the optimal range in another seven (10.9%) centres. Vaccine storage in the refrigerator was not proper in 47 (73.4%) centres. Majority of the centres had neither trained personnel nor budget for maintenance of the cold chain.Conclusion: There is a real danger of vaccines losing their potency at these centres even if they were potent on arrival. Relevant training for those handling the cold chain, improving the maintenance conditions of refrigerators and introduction of cold chain monitoring devises are recommended

    Additive Main Effects and Multiplicative Interaction Analysis of Coffee Germplasms from Southern Ethiopia

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    Additive main effects and multiplicative interaction (AMMI) analysis is a recently recommended effective method to study the genotype by environment (GxE) interaction pattern of multi-environment varietal trials. This work deals with modeling and examining the GxE interaction pattern of the multi-environment trials of 43 genotypes and eight environments from Southern Ethiopia coffee (Coffea Arabica L.) collections using a randomized complete block design (RCBD) with four replications. The work further attempts to predict yield based on the ammi model and evaluate and recommend high performing and adaptable varieties. The AMMI model with the first two interaction principal component axes (AMMI2) is found to be appropriate and parsimonious for the data. Environments e5, e6, e7, e8 and e3 are found to be high potential environments, where genotypes having high-yield (greater than 14 qt/ha) and resistant to Coffee Berry Disease (CBD) are associated. Among the 43 genotypes, 1, 9, 2, 3, 32, 12 and 25 are found to have the best performance with 3, 32, 12 and 25 being highly stable. Among the high-yielding genotypes, 33, 4, 23, 34 and 27 are found to be highly unstable and particularly adapted to environments 5, 6, 7 and 3, respectively

    Prevalence of Disability and Associated Factors among Registered Leprosy Patients in All Africa Tb and Leprosy Rehabilitation and Training Centre (ALERT), Addis Ababa, Ethiopia

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    BACKGROUND: Delay in leprosy diagnosis and treatment causes disabilities due to nerve damage, immunological reactions and bacillary infiltration. Leprosy disability leads not only to physical dysfunction and activity limitation but also disrupts social interaction of affected individuals by creating stigma and discrimination. This study was aimed at assessing leprosy disability status in patients registered at All African TB and Leprosy Rehabilitation and Training Centre.METHODS: Medical records of leprosy patients registered from September 11, 2010 to September 10, 2013 G.C were reviewed. Prevalence of disability calculated, bivariate and multiple logistic regressions were used to determine crude and adjusted odds ratios with 95% confidence interval.RESULTS: The overall prevalence of disability was found to be 65.9% from all categories of patients (40.2% Grade I and 25.7% Grade II). The Prevalence among the new category was 62.8% (39.1% Grade 1 and 23.7% Grade 2). Those ageed above 30 years, with duration of symptoms 6-12 months and above 24 months, with sensory loss, nerve damage and reversal reaction were more likely to develop disability.CONCLUSION: In this study the prevalence of disability, both Grade I and II, is very high. Disability was associated with age, duration of symptom, sensory loss, signs of nerve damage and reversal reaction. These risk factors indicate the existence of delay in diagnosis and treatment of leprosy cases. Therefore, the national leprosy control program should investigate leprosy case detection and diagnosis system in the country and work on improving early case detection and prevention of disability.KEYWORDS: Leprosy, leprosy disability, Ethiopi

    Determinants of acceptance of voluntary HIV testing among antenatal clinic attendees at Dil Chora Hospital, Dire Dawa, East Ethiopia

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    Back ground: Voluntary Counseling and Testing (VCT) is one of the best interventions to reduce mother to child transmission of HIV. Despite the proven benefits of VCT, many women are not willing to have HIV testing.Objective: The objective of this study was to identify factors that determine the acceptance of voluntary HIV testing among pregnant women attending antenatal care at Dil Chora Hospital in Dire Dawa. Method: The study employed unmatched case control study which was conducted from August 20 to September 10, 2006. The study population consisted of 234 antenatal care followers. Cases were antenatal care followers who werecounseled and tested for HIV in the current pregnancy. Controls were antenatal care followers who were counseled but not tested for HIV in the current pregnancy. Data were collected by trained enumerators using structured questionnaire. Univariate and multivariate analysis was carried out using SPSS version 12.0.1 software. Results: The majority (79.5%) of respondents (97.4% of cases and 60.5% of controls) had good knowledge on HIV, mother to child transmission and VCT. Marital status; knowledge about HIV, mother to child transmission and VCT; attitude towards VCT; antenatal care follow up and perceived benefits of VCT were independent predictors of acceptance of voluntary HIV testing. Conclusion: Knowledge on MTCT and VCT, positive attitude towards VCT, antenatal care follow-up were predictors of acceptance of VCT. During the VCT session, health professionals should focus on knowledge, attitude, and benefitsof VCT

    Human immunodeficiency virus (HIV) infection in tuberculosis patients in Addis Ababa

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    BACKGROUND: In a country with a rapidly spreading HIV epidemic information regarding HIV and TB Co-infection are lacking. OBJECTIVES: To determine the prevalence of HIV infection in a representative sample of sputum-positive tuberculosis patients. METHODS: A cross-sectional survey whereby blood sample was collected from 236 consecutively coming smear positive pulmonary tuberculosis patients for HIV testing. This study, which involved all the health centres in Addis Ababa, was carried out during August 1, 1998 to the end of December 1998. RESULTS: Of the 236 blood samples collected, 107(45.3%) were HIV positive. Among the HIV positives, 66 (61.7%) were male and 41(38.3%) females. The HIV-TB co-infection was highest in the age group 20-49 and the largest number of TB co-infection (75% of all such co-infection) was found in the 20-39 age group. There was no significant difference between the HIV positive and negative TB patients concerning to other socio-demographic factors or presenting symptoms. CONCLUSION: The prevalence of co-infection appeared to have increased compared to previous studies, 6.6%, 20 & 25% and 44.4% in 1990, 1995, and 1996, respectively. This trend may have a serious impact on the control of tuberculosis. Co-ordinating strategies of the TB and HIV control programs is recommended. (Ethiopian Journal of Health Development, 2000, 14(3): 277-282

    Marketing of Kabuli and Desi chickpeas by smallholder farmers in Eastern Shewa Zone

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    An understanding of the market for smallholder farmers’ crops can provide clues to the potential market for their crops. The main objective of this study was thus to analyze the marketing performance of Kabuli and Desi chickpeas in three districts of east Shewa zone. It investigated the socio-economic, demographic, and institutional factors and other marketing attributes that affect farm gate-prices, season price fluctuations and marketable surplus of chickpeas in the study areas. A sample of 700 randomly selected households was interviewed using a structured questionnaire. Secondary data from different sources were also used. Both descriptive and econometric methods were used to analyze the data. The conceptual and empirical evidence suggests that improving smallholder farmers’ awareness for the uptake of improved Kabuli varieties for which the marginal values of varieties are considerably high relative to the price of the inputs would improve farm-gate net returns and prices received by small producers. The marketable surplus will also be improved if farmers switch to production of improved varieties of Kabuli chickpeas. Supplementary production relation ship between crop and livestock enterprises was found to be one of the important solutions to alleviation of high price variability that reduces competitiveness of chickpea marketing. In addition to the crop and livestock supplementary enterprise relation ship, moving for off-farm income activities with out affecting negatively the crop and livestock farming was found another alternative to alleviation of the high price variability problems. The study, however, ascertains that smallholder farmers need to know not only how to produce but first need to know and learn how to identify preferable potential buyers that will enhance competitiveness of chickpea market
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