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UNDERSTANDING GEOMAGNETIC STORM IN RELATION TO THE SUNSPOT NUMBER DURING SOLAR CYCLE 24 AND 25
(Mekelle University, 1994-12-28) Tesfaye Ayalew
Geomagnetic storms, caused by disturbances in Earth’s magnetosphere due to solar activity, are significant drivers of space weather and have profound effects on technological systems and infrastructure. This study investigates the relationship between geomagnetic storms and sunspot numbers, a primary indicator of solar activity, during solar cycles 24 and 25. Solar cycle 24, marked by historically low sunspot numbers and subdued solar activity, contrasts with solar cycle 25, which is projected to exhibit increased solar intensity. The research employs a multi-faceted approach, analyzing data from solar wind parameters, interplanetary magnetic fields, and geomagnetic indices such as Dst and Kp. Through statistical analysis and correlation studies, it examines the influence of sunspot number variations on the frequency, intensity, and duration of geomagnetic storms. Additionally, the study explores the distinct characteristics of geomagnetic activity during these two solar cycles, identifying key patterns and trends. By establishing a clearer understanding of the connection between sunspot numbers and geomagnetic storms, this research contributes to the development of more accurate predictive models for space weather events. These findings hold significant implications for improving preparedness and mitigation strategies to safeguard satellite operations, communication systems, and power grid stability against space weather impacts.
Role of Small-Scale Irrigation on improving Food Security of Households A case study of two peasant Association Tabia Maytuem and Betyehannes in Adwa district, Tigray Regional state
(Mekelle Univeristy, 2013-09-28) Yemane Tesfay
Food insecurity in the world has been addressed as one of the biggest problems for over several decades due to the result of high population. Ethiopia’s agriculture is dominated by small-scale rain-fed production and irregular rainfall pattern. Small-scale irrigation is believed in helping to address this problem thereby reducing rural poverty, food insecurity as well as improving the overall contribution of agriculture to the national economy. The main objective of this study was to investigate role of small scale irrigation user’s on improving food security of households in Adwa Rural District (Tabia Maytuem and Betyehannes). Data was collected from 195 household, 80 irrigation users and 80 non-users, 24 for group discussion, 6 key informative and 5 agricultural experts. Two Tabia was stratified into two strata and random sampling technique was employed to select the sample respondents. According to the findings, small-scale irrigation were very important to increase their yields, income, to keep their health, teach their children, and help their economy gained by rain-fed. The households are interested in getting advice of agricultural experts in order to do highly in irrigation. When compared household’s food security improvement who practice irrigation and non-irrigated lands, there was a great difference of diet diversity between the two groups. Irrigators gain alternative and fresh food than non-irrigators; as a result, irrigators’ health was better than non-irrigators because non-irrigators’ can be affected by deficiency diseases. The researcher obtained different factors that influence small scale irrigation schemes on the improvement of food security like, incomplete infra-structure, shortage of water, fertilizer, medicine, link to marketing, genetically modified crops, vegetables, legumes, fruits, rules of water financing committee, drought, awareness, advise, work-shops, sharing experiences and commitment. Finally, it was recommended that governmental and non-governmental organization should expand access of small- scale irrigation by farm households to improve their food security.
Analysis of Multi-environmental Trial Data Using AMMI and GGE Biplot on Barley Genotypes Evaluated in Tigray
(Mekelle University, 2023-11-08) Tamrat Berhe
Barley (Hordeum vulgare L.) was one of the first plants people grew for food, and now it's grown all over the world and it has a special role in Ethiopian agriculture. However, production is affected by environment interaction and lack of stable genotypes across locations. The presence of genotype-environment interaction (GEI) influences production making the selection of cultivars in a complex process. Since, this experiment were conducted for forty barley genotypes by Alpha lattice design using two replications at three locations in Tigray during 2017 and 2018 cropping seasons considering each year-location combination as a different environments. The study carried out with objectives to estimate magnitude of genotype by environment interaction, comparing AMMI and GGE to evaluate stability of genotypes and identifying superior genotypes. We observed significance effects in all sources of combined ANOVA, since the grain yields of all 40 barley genotypes were significantly affected by environment, which accounted for 40.6 % of the total variation, whereas genotype and genotypeenvironment interaction accounted for 21.12 % and 23.07 %, respectively. The two most used methods to analyze GEI and evaluate genotypes are AMMI and GGE Biplot, being used for the analysis of multi environment trials data (MET).Both models were equivalent for the data’s evaluation, but GGE permitting increased reliability in the selection of superior cultivars (Which-won-where pattern) and test environments (discrimitiveness vs. representativeness).Wricke’s ecovalence, Finley-Wilkinson, Shukla’s stability, Lin&Binns cultivar superiority measure, AMMI Stability Value (ASV), and YSI stability analysis measures also used to identify stable genotypes, and G19, G36, G5 are the most stable genotypes in almost the stability analysis measures, since they are superior genotypes with all test environments. While the genotypes G33, G32, G12 and G18 also the instable genotypes in the test environments. GGE Biplot view of relation among test environments of this study showed that; Among the testing environments Hagereselam 2018 is an ideal testing location to identify stable and high yielding genotypes followed by Ayba 2018, since Hagereselam 2018 and Ayba 2018 are most applicable test locations for identifying stable and high yielding barley genotypes for the region. Mean performance and stability of GGE biplot indicated that G24 had the ideal genotype with highest mean yield as well as stability with desirable genotypes G20, G19, G5, G36, while G33 and G30 had the lowest mean yield and less stability genotypes in all the six test environments.
A Multilevel Structural Equation Modeling Approach to Estimate Incompletion of Childhood Vaccination among 12-39 months old in Ethiopia
(Mekelle University, 2023-11-28) Brtawit Aregay
Background: Childhood immunization is a worldwide ultimate public health intervention significantly plummeting morbidity and mortality linked with preventable diseases. Despite significant efforts to improve vaccination coverage, a considerable proportion of children aged 12-39 months in Ethiopia remaining incompletely vaccinated. Objective: This study intended to employ a Multilevel Structural Equation Modeling (MSEM) approach and framework to broadly analyze the elements contributing to incompleteness of childhood vaccination in Ethiopia. Methods: The study utilized secondary data from the Ethiopian Mini Demographic and health Survey (EMDHS) and adopted both qualitative and quantitative research approaches under descriptive research design. A multilevel logistic regression approach was employed to capture the interplay between individual and community-level factors impacting childhood vaccination status. At individual level, age, sex, education, marital status, and vaccination card were considered, while at the community level, factors such as antenatal care, place of delivery, poverty, media exposure, and living area were explored. The study established a conceptual model integrating these factors and applied a multilevel structural equation modeling approach to estimate their direct and indirect relations with incomplete childhood vaccination. On top of this, the pathways and interdependencies between variables were examined to elucidate the complex associations influencing vaccination outcomes. Results: Preliminary analyses revealed significant direct effects of urban residence (AOR=2.1 & 95%CI of AOR [1.1,3.6] and age (AOR=11.5 & 95% CI of AOR [1.1,2.1]) On childhood vaccination. Additionally, community-level factors such as primary school maternal education (AOR=1.8 & 95% CI of AOR [1.3, 2.5]) and antenatal care follow-up (ANC: AOR=1.5 & 95%CI of AOR [1.0,2.2]) demonstrated varying degrees of influence on vaccination status. Conclusions: The findings from this study grasp noteworthy implications and roles for national and global public health interventions. By identifying the multilayered elements impacting incomplete child vaccination, this research aims to provide evidence-based recommendations to reinforce vaccination programs and reduce the burden of vaccine-preventable diseases among Ethiopian children aged 12-39 months. Furthermore, the contributions of this study lie in its application of a wide-ranging multilevel structural equation modeling (MSEM) approach and framework, offering a nuanced understanding of the intricate web of determinants contributing to incomplete childhood vaccination in Ethiopia. The results are expected to inform targeted interventions and policy changes aimed at enhancing vaccination rates and safeguarding the health of children in national and regional level of Ethiopia as particular and worldwide in general.
Statistical Analysis of Multi Environment Trials on Durum Wheat: The Use of AMMI and Stability Indices to Model Genotype by Environment Interaction
(Mekelle University, 2023-11-28) Shshaye Hailu
Background: Durum wheat is one of the most important crops worldwide with an annual production of 37 million tons and Ethiopia is the major durum wheat producer in Sub-Saharan Africa (SSA). Crop breeders have worked to create genotypes with improved grain production, quality, and other desirable qualities under a variety of diverse environmental situations. Genotype × environment (G×E) interaction is one of the main complications in the selection of broad adaptation in most breeding programs. Objective: The goal of the study was to assess genotype by environment interaction in multienvironment trials and identify stable and adaptive durum wheat varieties using AMMI and stability measures. Method: The experiment was conducted at Beati-Maymesanu in Ganta-Afeshum Woreda, Agarba in Degua Tembein Woreda, Atsela in Emba Alajie Woreda, and Zata in Ofla Woreda during in 2015 and 2016 under Production and contrasting growing conditions. Thirty six durum wheat varieties were released using Simple Alpha Lattice design with two replications. This study was used AMMI and stability measures for assessing among environments and genotypes. Result: The Combined analysis of variance revealed highly significant difference among genotypes, environments and GEI for durum wheat. Stability analysis of grain yield was executed using environmental variance, shukla‟s stability, Wricks‟ ecovalence and AMMI stability value (ASV). The analysis of variance for the AMMI model were highly significant variation differences between genotypes, environments and the interaction effect of G x E. The first two interaction principal component axes (IPCA) of the AMMI model accounted for 48.73% of the total G x E interaction sum of squares for grain yield. Conclusion and Recommendation: According to the AMMI biplot analysis, Genotypes G30 (55D3), G11 (248478) and G25 (236295) were more stable, while, G33 (222415) and G21 (8436) are the unstable genotypes and E5 (Beati-Maymesanu-2016) was the highest yielding environment while, E8 (Zata-2016) was the low yielding among eight environments. Keywords: AMMI, Genotype by Environment interaction
Modeling a Repeatedly Measured Farmyard Manure and Gypsum Intervention on Yield of Sorghum in Saline Sodic Soils
(Mekelle University, 2023-11-28) Elias Tafere
Background: Salinity is one of the major environmental problems the world is currently dealing with, and it also poses the biggest obstacle to agricultural productivity, especially in arid, semiarid, and dry sub humid regions. Sorghum is the most produced grain in Raya Alamata, Southern Tigray of Ethiopia. Soil salinity in this area often affects sorghum yield and yield characteristics. In order to tackle the effect soil salinity/sodicity status, ongoing assessment and monitoring on fertilizer intervention should be conducted in the stated study area Objective: The aim of this thesis is, hence, twofold: to propose repeated measure analysis to take into account the problems with traditional approach; and make use of this approach to scrutinize the optimum rate of gypsum and farmyard manure fertilizers for improving sorghum yield in saline sodic soils of Raya Alamata, Southern Tigray of Ethiopia with an emphasis on the use of mixed modeling techniques with repeated measures. Method: The study involved secondary repeated measure or longitudinal data, collected using field experiments during three consecutive years of the same plots to illustrate different modeling strategies and graphical tools with an emphasis on the use of mixed modeling techniques with repeated measures. Mixed modeling approach is the most flexible method in terms of handling the covariance among repeated measures. Result: The Breusch Pagan method shows Pooled OLS model is not the best estimation method (p-value=0.000). Hausman Test output also indicates random effect model outperforms compared to the fixed effect (p-value=1.000). The spaghetti plot showed that the increasing trend with time. A positive linear relationship was also observed between yield measurements taken at different years, confirming the strong correlation. The mean yield with 0% GR was 34.23qt/ha but 36.33 qt/ha and 37.58 qt/ha after addition of Gypsum 50%GR and 100% GR respectively. Similarly there was a better yield after adding FYM when compare to the control. The mean yield is increasing over time, the mean yield is 35.47, 35.94 and 36.72 at first, second and third year respectively. The maximum yield 40.25 also recorded in the third year. Sole application of 8 tha-1 FYM and combination of FYM and Gypsum rate at (50%GR+8 tha-1 FYM) have significance role on production yield of sorghum on salinity area of Raya Alamata over three consecutive years with p-value < 0.000 at =5% level of significance respectively. Conclusion and Recommendation: The study found that repeated measure analysis using mixed modeling techniques yields a better result than a traditional approach (OLS). The result from the Bonferroni mean comparison further revealed that combination 8tha-1 FYM and 50% GR are the optimum level of fertilizers that provide improved sorghum yield in saline sodic soils of Raya Alamata, Southern Tigray of Ethiopia.
Prevalence & Risk factors of Patent Ductus Arteriosus (PDA) in Preterm Neonates: Evidence from Survival & Shared Frailty Model
(Mekelle University, 2023-11-28) Nigus Gebreab
Background: The ductus arteriosus is a leftover fetal artery connecting the main body artery (aorta) and the main lung artery (pulmonary artery). The ductus allows blood to detour away from the lungs before birth. Every baby is born with a ductus arteriosus. After birth, the opening is no longer needed and it usually narrows and closes within the first few days. Patent ductus arteriosus (PDA), resulted when this artery remains open (patent) after birth, is a heart problem that occurs soon after birth in some babies. Its human and economic loss is too much in general if it is not treated at all or treated early. Objective: The overall objective of this study was to assess prevalence of PDA in preterm neonates; their survival time (time to death) & associate risk factors. Methods: To address the study objective, a secondary data from Health Facilities of Mekelle City was collected from 125 preterm neonates who initiated their follow up between December 2019 and December 2020. The Cox PH model with parametric shared frailty distribution where hospitals (health facilities) preterm neonates treated used as a clustering effect in the models. The gamma and inverse Gaussian shared frailty distributions with Exponential, Weibull and log-logistic baseline models was employed to analyze risk factors associated with age at circumcision using socio-economic and demographic factors. All the fitted models were compared by using AIC and BIC values from actual dataset. Results: A total of 125 children were seen at the Health Facilities of Mekelle City during the study period. The result revealed that about 20% of preterm neonates were exposed to PDA while the remaining were not. The AIC value for the three baseline distributions (Exponential, Weibull, and Gompertz) of PH model was found 173.6275, 174.6895, and 175.6086 and the BIC value of those baseline distributions for the same model was also found 216.0522, 219.9425, and 220.8616 respectively. The AIC value for the three baseline distributions for gamma shared frailty model was found 172.5497, 176.6895, and 176.6896 (the same value with Weibull) and BIC value of those baseline distributions for the same model also found 220.8805, 224.7708, and 224.7708 (the same with Weibull) respectively. Based on AIC and BIC values from simulation experiment and graphical evidences, Gamma shared frailty model, with the exponential baseline preferred when compared with other models. The clustering effect (the hospital effect) was significant for modeling the determinants of time-to-death preterm neonates with PDA. The estimated value of ix | P a g e theta (θ) which is a measure of contribution of a frailty component to the model was 1.1056 and a chi-square value of 0.003722 with one degree of freedom resulted a p-value of 0.0027. Based on the result of Gamma shared frailty model with the exponential baseline, gestational age, birth weight, place of delivery at home, maternal history with HIV, and treatment with paracetamol were found to be the most significant risk factors of the outcome variable, survival time (time to death from PDA). The hazard ratio and 95% Confidence interval of gestational age and birth weight was also 2.0742 with CI (0.5905259, 0.9013781) and 2.7191 with CI (1.000007, 1.000614) that yielded a p-value of 0.003 and 0.045 respectively. The hazard ratio and 95% CI for the covariates place of delivery at home, maternal history with HIV, and treatment with paracetamol were 5.1852 with CI (0.7416363, 5.1268725), 2.139 and (2.417719, 263.6325), and 42.0056 with (-3881.608, 3846.564) which yielded a p-value of 0.0092, and 0.007 respectively. They have also a prevalence rate of a unit (for place of delivery at home and maternal history with HIV) and 0.13 for treatment with paracetamol (No). The overall prevalence rate was also yielded 0.32. Conclusions: The model suggested that there is a strong evidence of heterogeneity among health facilities where the preterm neonates were treated. From the candidate models, Gamma shared frailty model, with the exponential baseline was an appropriate model for predicting the PDA data. There was a frailty effect on the survival of the preterm neonates that arises due to differences in the distribution of hospitals of the neonates. The risk factors place of delivery at home, maternal history with HIV, gestational age (week), Birth weight, and treatment with paracetamol were statistically significant for the survival of preterm neonates whereas the other risk factors were not statistically significant. The frailty component had also a significant effect to the model
Analysis on utilization of maternal health care service in Ethiopia: Using Ethiopian Mini Demographic and Health survey
(Mekelle University, 2023-11-28) Hiwot Amaha
Background: The World Health Organization (WHO) established the "Safe motherhood package" as a manual for interventions in maternal and child health, and it lists antenatal care as the fundamental intervention in lowering maternal and infant mortality. Antenatal Care for women and children starts with their immediate health issues and extends to their long-term wellbeing as well as the wellbeing of the community. Getting in touch with mothers and identifying and managing present and future risks and issues are the main goals of prenatal care. It is regarded as one of the most crucial for the mother's health, the fetus's optimal development, and preventing or lessening pregnancy complications (Fantahun M, 1992). Methodology: This research used cross sectional study design retrieved from Ethiopian MiniDemographic and Health Survey 2019 to assess factors affecting utilization of maternal health care services in Ethiopia. This study analyzes responses from 3979 women age 15-49, who have at least one child under age five at the time the survey was fielded. Result: Women from Urban areas were more likely to receive ANC care than women from other rural areas. The bivariate results show a significant difference in the use of maternal health care services by age, marital status, women’s education, parity, wealth, religion, and family size as significant and independent predictors for the use of antenatal care. And age, wealth, region, residence, women’s education, parity, religion and family size are significance and independent predictors for the use of delivery care services in Ethiopia. Bivariant and multivariate analysis showed significant association between ANC and maternal age, women’s education, religion and wealth. Age (OR=1.527, 95%CI=1.102,2.116), Education (OR=1.731,95%CI=1.434,2.090), religion (OR=1.829,95% CI=1.386, 2.414), wealth (OR=2.234,95% CI= (1.758, 2.839) and residence (OR=.387,95% CI= 290, .516) were associated with choice of delivery site. Education and parity were found to be strong predictor of both antenatal care and delivery care. Conclusion: In brief, the study discovered low maternal health care utilization in the area. Increasing maternal health service coverage and promotion of IEC in the community are recommended.
A Mixed Effect Model for Unbalanced Longitudinal Haematocrit Level Evolution Progress of Chronic Kidney Failure Patients
(Mekelle University, 2023-11-28) Getachew Beyene
Background: Chronic Kidney Disease (CKD) or renal failure is a public global health problem with an estimated prevalence of as 8 to 16% worldwide. This study was conducted inorder to investigate the evolution of hematocrit levels over time in renal patients after their transplant and to determine how the evolution depends on the age and gender of the patient and other factors. Objective: The main objective of this study is to employ a mixed effect model to examine the unbalanced longitudinal evolution progress of hematocrit levels in chronic kidney failure patients. Methodology: This is a longitudinal study that consisted of 1160 patients who received a renal transplant. These patients were followed up for a period of 10 years at most. Haematocrit level was considered as the response while the covariates were time in years, gender and age of the patients just to mention a few. Different statistical methods such as explanatory analysis, multivariate regression model, two stage analysis and linear mixed effects model were employed to explore the evolution of hematocrit over time. Results: Results revealed that haematocrit levels in kidney transplantpatients evolve over time. Gender and age of the patient have significant effect on the evolution of haemotocrit levels. Males tend to have a higher increase in haematocrit levels over time than females. With regard to age, haematocrit levels tend to increase with increasing age. Furthermore, it was observed that experience of cardio-vascular problems before transplant and rejection symptoms did not have a significant effect on the evolutionof haematocrit levels. Conclusions: Hematocrit levels evolve over time and this evolution follows a quartic time effect. The change in haematocrit levels varies according to the gender and age of the patient after a kidney transplant. Patients starting with low haematocrit levels tend to have a larger increase overtime.
Investigating the Impact of Laboratory and Practical Activities on Chemistry teaching and Learning: A Case Study of Grade 10 Students at Weldu Negus Secondary and Preparatory School
(Mekelle University, 2024-11-25) Geberemariam Fissha Abebe
Chemistry laboratory activities play a crucial role in enhancing students’ understanding by providing hands-on experience that reinforces theoretical knowledge. This study examines the impact of laboratory-based teaching on student performance and attitudes at Weldu Negus Secondary and Preparatory School. A quasi-experimental research design was employed, where 263 Grade 10 students were divided into experimental and control groups. The experimental group engaged in hands-on laboratory activities, while the control group received only theoretical instruction. Data were collected through questionnaires, interviews, and post-test assessments, and statistical analysis was conducted using SPSS. The findings revealed that students in the experimental group demonstrated a significant improvement in their post-test scores, with 88.65% scoring above 50, compared to 54.54% in the control group. This highlights the effectiveness of laboratory-based instruction in improving student comprehension and engagement. Despite these benefits, several challenges were identified, including a lack of laboratory equipment and chemicals, insufficient trained personnel, time constraints, and limited teacher preparedness. Additionally, 61.9% of students expressed disinterest in laboratory activities, indicating the need for more engaging and student-centered approaches. Based on these findings, the study recommends improving laboratory facilities, providing professional development for teachers, integrating student-centered teaching methods, and increasing student motivation through real world applications of chemistry. Collaboration with external institutions and regular monitoring of laboratory practices are also suggested to sustain improvements in practical chemistry education. Future research should explore the long-term impact of laboratory-based learning on student career choices and the effectiveness of digital and virtual labs as supplementary tools. Implementing these recommendations will create a more effective learning environment and foster deeper scientific understanding among students.
Shared Frailty Model in Survival Analysis of Time to Discharge Dynamics for Myocardial Infarction Adult Patients at Ayder Comprehensive Specialized Referral Hospital (Jan 1, 2018 - Dec 31, 2020)
(Mekelle University, 2024-11-28) Gebrewahd Tewelemedhin
Background: MI, commonly known as heart attack, happens when a blood clot obstructs the coronary arteries, resulting in decreased oxygen and nutrient supply to the heart muscle. MI continues to be a significant cause of morbidity and mortality globally, with variations in the time-to-discharge dynamics among patients. Understanding the time to discharge is crucial for optimizing patient care and resource allocation, particularly in settings with limited healthcare resources like Ayder Comprehensive Specialized Referral Hospital. Objective: The overall objective of this study was to investigate and gain a comprehensive understanding of the time to discharge dynamics in MI patients at Ayder Comprehensive Specialized Referral Hospital, using a survival analysis with a shared frailty model. Methods: To fulfill the study goal, secondary data from Ayder Comprehensive Specialized Referral Hospital was collected from 206 MI patients who initiated their follow-up between January 2018 and December 2020. K-M curves used to compare the survival curve for categorical variables and the univariable analysed used Cox regression model to select variable which were included in the multivariable analysis. The Cox PH model with a parametric shared frailty distribution was utilized, with the follow-up site where treatment was administered serving as a clustering effect in the models. The study employed gamma and inverse Gaussian shared frailty distributions alongside Exponential, Weibull, and log-logistic baseline models to analyze the risk factors associated with survival time until discharge, considering socioeconomic and demographic factors. All fitted models were compared using the AIC and BIC values derived from the actual dataset. Results: Of the 206 patients were seen at Ayder Comprehensive Specialized Referral Hospital during the study period. The results revealed that approximately 54% experienced the event, while 46% did not experience it by the end of the follow-up period. The AIC values for the three baseline distributions (Exponential, Weibull, and Gompertz) of the PH model were found to be 370.8967, 90.3539, and 96.2921, respectively. The corresponding BIC values for those baseline distributions were 424.1427, 146.9278, and 152.8661, respectively. The AIC values for the three baseline distributions for the Gamma shared frailty model were found to be 375.4022, 89.2839, and 98.5131, with the BIC values for the same model found to be 431.9761, 148.9278, and ix | P a g e By: G/wahd T. 155.4568, respectively. Based on the AIC and BIC values from the simulation experiment and graphical evidence, the Gamma shared frailty model with the Weibull baseline was preferred when compared to other models. The clustering effect (follow-up site) was found to be significant for modeling the risk factors of time-to-discharge patients with MI. The estimated value of theta (θ), which measures the contribution of a frailty component to the model, was 1.1056. A chi-square value of 0.00372 with one degree of freedom resulted in a p-value of 0.0031. Based on the results of the Gamma shared frailty model with the Weibull baseline, the follow-up site at the medical ward, obesity (BMI > 30), age (in years), weight, diabetes mellitus, family history of MI, uncontrolled blood pressure, high cholesterol levels, and male gender were identified as the most significant risk factors for the outcome variable, survival time to discharge. The hazard ratio and 95% confidence interval for patient age and weight were 0.9844 (CI [1.0105, 1.5116]) and 1.0101 (CI [0.0193, 0.9879]) with p-values of 0.002 and 0.019, respectively. The covariates, including follow-up site at the Medical ward, BMI with obesity (BMI>30), diabetes mellitus, family history of MI, uncontrolled blood pressure, high cholesterol levels, and male gender, exhibited hazard ratios of 2.4868 (CI [0.4281, 1.4369]), 2.3445 (CI [0.3901, 2.1253]), 2.7563 (CI [0.582, 1.5858]), 3.7139 (CI [0.0152, 1.3031]), 1.0726 (CI [0.3823, 1.8024]), 1.7318 (CI [0.3385, 1.3835]), and 4.1012 (CI [0.0110, 1.1967]), respectively, with associated p-values of 0.018, 0.001, 0.003, 0.021, 0.026, 0.013, and 0.001, indicating their respective impacts on the study outcomes. Conclusions & Recommendation: The model suggested that there is a strong evidence of heterogeneity among follow up sites where the MI patients were treated. From the candidate models, Weibull-gamma shared frailty model was an appropriate model for the MI dataset. There was a frailty effect on the survival of the MI patients that arises due to differences in the distribution of follow up sites. The risk factors follow-up site at the medical ward, being obese, age(in years), weight, diabetes mellitus, family history of MI, uncontrolled blood pressure, high cholesterol levels, and male gender were statistically significant for the survival of MI patients whereas the other risk factors were not statistically significant. Health care providers must focus on high-risk MI patients, considering factors like age, obesity, uncontrolled blood pressure, diabetes, high cholesterol level, gender, and family history of MI.
SURVIVAL ANALYSIS FOR HIV-TB CO-INFECTED PATIENTS UNDER ANTIRETROVIRAL THERAPY IN MEKELLE HOSPITAL AND AYDER COMPREHENSIVE REFERAL HOSPITAL TIGRAY, ETHIOPIA: APPLICATIONS OF A PARAMETRIC SHARED FRAILTY MODEL
(Mekelle University, 2024-11-28) Tekleweyni Haftu
Background: Human immunodeficiency virus (HIV) is an infection that attacks the body’s immune system. Acquired immunodeficiency syndrome (AIDS) is the most advanced stage of the disease. HIV remains one of the world's most significant public health challenges, particularly in low- and middle-income countries. Objectives: This study aimed to determine the potential risk factors affecting the time-to-death of HIV-TB co-infected patients in Mekelle and Ayder Comprehensive Referral hospitals and also demonstrate the application of parametric survival models in analyzing these survival outcomes. Methods: Parametric shared frailty models have been used with four baseline hazard functions (Exponential, Weibull, Log-logistic, Log-normal) and two frailty distributions (Gamma, InverseGaussian). 215 HIV-TB co-infected patients whose age was 18 and above who started ART from January 2015 to December 2016 and followed up to January 2020 were included in the study from Mekelle and Ayder hospitals. Data were analyzed using statistical software R version 4.4.1 and STATA version 14.0. Results: Out of 215 patients, about 60(28%) died while 155(72%) were censored during the follow-up period with the median death time of HIV-TB co-infected patients at 30 months. The clustering effect was significant, and the Weibull-Inverse Gaussian shared frailty model was preferred over the rest parametric shared frailty models based on the Akaike Information Criterion (AIC) and Bayesian Information Criteria (BIC). The result shows patients’ educational level, baseline Weight, TB type, baseline CD4, and place of residence were significant, whereas sex, WHO clinical stage, marital status, functional status, regimen type, and age were not significant covariates for HIV-TB co-infected patients in Mekelle and Ayder comprehensive Referral hospitals. The clustering effect was significant for modeling the time-to-death of HIV-TB patients’ dataset and there was heterogeneity among the hospitals on the death of patients (θ=040.). Conclusion: This study showed that there was a clustering (frailty) effect on modeling time to Death among patients treated in Mekelle and Ayder comprehensive hospitals because of heterogeneity in hospitals from which the patients are treated, assuming patients treated in the same hospital share similar risk factors related to death.
Bayesian Survival Analysis of Adult Tuberculosis Patients: the Case of Lemlem Karl Hospital, Maichew, Southern Tigray.
(Mekelle University, 2024-11-28) Lemlem Tekle
Tuberculosis is an airborne disease caused by the bacterium Mycobacterium tuberculosis, primarily affects the lungs. Transmission occurs through the air when individuals with pulmonary TB are not undergoing proper treatment. This study aimed to identify factors affecting the survival time of adult TB patients in LKH, Maichew, and Southern Tigray. To address the objective of this study, 242 adult TB patients were included in the study based on data taken from the medical records of patients enrolled from July; 2020 to January; 2024. Almost half, 50.4%, of the adult TB patients were female. Kaplan Meier plots were used for comparison of survival function; Bayesian survival models were used to identify factors affecting the survival time of adult TB patients. Of the total patients in the study 178 (73.6%) were censored. The estimated median survival time of patients was 26 months. Bayesian log-normal accelerated failure time model using MCMC and INLA method fit adult TB data better than other Bayesian accelerated failure time models used in this study. The Bayesian log-normal accelerated failure time model using the INLA method was preferable to the MCMC method due to smaller standard error and narrow credible interval. The results of this model show that the survival time of adult TB patients is significantly affected by age, residence, body weight, HIV status, BMI, dose level and cigarette smoking of adult TB patients(pvalue<0.05). Bayesian log-normal accelerated failure time model using the INLA method describes the adult TB dataset well. From the Bayesian result, the risk factors for the survival time of adult TB patients were age group (31 to 45, 𝛾 = 0.8607),(46 to 60, 𝛾 = 0.7189)and( >60, 𝛾 = 0.6637);residence(rural,𝛾 =0.7408); HIV (Positives, 𝛾 = 0.68386); Dose (III, 𝛾 = 0.6570) ,IV 𝛾 = 0.9512),BMI(Overweight, 𝛾 = 0.8607) and (Obese 𝛾 = 0.0779); base line weight(> 50kg, 𝛾 = 0.8693) and (smokers, 𝛾 = 0.8607) at 95% credible interval and those factors were prolonged the timing death of adult TB patients. Therefore, health professionals should focus on the identified factors to improve the survival time of TB patients.
SPATIAL DISTRIBUTION AND DETERMINANTS OF ANAEMIA AMONG WOMEN OF REPRODUCTIVE AGE IN ETHIOPIA USING MIXED-EFFECT ORDINAL LOGISTIC REGRESSION MODEL
(Mekelle University, 2024-12-28) Solomon Tekeste
Background: Anaemia is a condition characterized by a low blood hemoglobin concentration (120 g/L in non-pregnant women and below 110 g/L in pregnant women). It primarily affects women of reproductive age (WRA) and who suffer from anaemia has experienced detrimental effects on their mental development and future social functioning. Objectives: This study aimed to assess the spatial distribution and determinants of anaemia among women of reproductive age in Ethiopia. Methods: The study participants were all the WRA who were confirmed to anaemia from the 2019 EMDHS data source. The survey considered 8885 WRA; of which 1483 severe, 534 moderate, 1778 mild and 5090 none anaemia levels were included in this study. The study variable was defined as the ordinal level of anaemia (none, mild, moderate and severe) based on the WHO cut-off points. In this study, Moran’s-I, was used to investigate the presence of spatial autocorrelation. A mixed effect ordinal logistic regression model used allowed to analyze random and fixed effects of some covariates, spatial effects, and other fixed covariates. Inference used a full GLMM and several methods can be used to assess the goodness of fit in GLMMs, including the AIC and BIC techniques. Results: Out of 8885 WRA; included in this study 1483(16.7%) were found at a severe level of anemic. Due to the BIC model selection criteria, the GLMM model was found to be appropriate. From the model Individual factors (age group, religion, wealth index and marital status) and community factors (cooking fuel type, number of children, access to electricity, and having refrigerators) are found to be determinants, significant determinants of anaemia status among WRA and the spatial analysis demonstrated a clustered pattern of anaemia distribution, confirmed by the global Moran's I statistic (0.146652, p-value < 0.001). Conclusion: The finding revealed a spatial variation of anaemia status among WRA across the regions of Ethiopia with higher prevalence in the eastern parts of the country specifically in Somali and Harari regions. The application of the GLMM provided a more detailed understanding of the factors influencing anaemia status.
RADIO-LOUD CME-CME POTENTIAL INTERACTIONS IN SOLAR CYCLE 24 IN THE YEARS 2009-2018
(Mekelle University, 2024-12-28) Mebrahtu Gebremedhin Teka
Radio loud (RL) CMEs are those associated with solar type II radio bursts. These CMEs might interact with each other on their way from the solar surface to the interplanetary medium. As a result ,these CMEs leave a radio signature on the dynamic spectrum and bright white enhancement on the white-light images. In this research ,we have found a total set of 32 possible interacting CMEs and 16 associated DH type II bursts are registered on the NASA SOHO/LASCO CDAW catalogue for the period spanning from 2009 to 2018. However , only the DH component of the radio bursts were considered. This possibility of interaction was estimated by a thorough investigation of the origins of the CMEs and the simultaneity of enhancement on the CMEs difference images on the LASCO field of view and the intensification of the burst on the dynamic spectrum of the Wind/WAVES. A primary CME is mainly emitter of the DH burst and the preceding interacts with it. By tracking the whitelight images of these CMEs ,the height-time diagrams are obtained. Our results show that most of the primary CMEs are halo and averagely much faster (1482.3 kms-1) than the preceding CMEs (841.6 kms-1). More over ,drift rate of DH type IIs ,time duration of pre and pri-CMEs and interaction height are found to be 1.82 MHzs-1 , ∼34.6 min and ∼5.3 Ro ,respectively. The pre-CMEs are found to be less energetic than the primary CMEs. Most of the interacting CMEs were originating from the western regions of the Sun. Studying the properties of interacting RL CMEs and their kinematics are important to be able to make predications before a CME arrival and make proper arrangements both on the ground and in space.
COMPARATIVE STEADY OF EARTH’S MAGNETIC FIELD VARIABILITY, SQ-CURRENTS AND EQUATORIAL ELECTROJET OVER INDIAN, AFRICAN AND AMERICAN SECTORS
(Mekelle University, 2024-12-28) Bogale Fentaye
The earth’s magnetic field during day and night is not the same due to different factors. The sun’s radiation is one of the parameters to influence the variability of the earth’s magnetic field in different sectors. The variation of magnetic field in turn produces huge variation in ionospheric currets such as the Sq- current, Equatorial Electrojet (EEJ), counter electrojets (CEJ). Equatorial electrojet (EEJ) is enhanced current flowing from west to east during day time at dip equator between ±30 latitude at an altitude of about 107 Km. This high concentration of electric current flowing from west to east in a narrow belt flanking the dip equator on the sunward hemisphere has been termed the equatorial electro jet. Our objective is to study , variation of the earth’s magnetic field strength, Sq- current, EEJ and CEJ for African sector and American sector and the Indian sector. The magnetic field strength in the Indian sector is relatively stronger as the geomagnetic equator passes close to southern India, influencing EEJ intensity and variability. While in the African sector, the geomagnetic field is weaker compared to the Indian sector, resulting in higher ionospheric conductivity and often stronger EEJ current, When we come to the American sector the Geomagnetic field is relatively weakest but features a more significant magnetic declination (the angle between geographic and geomagnetic north), particularly in the south America. The declination impacts the electrodynamics, introducing additional east-west variability.
UNDERSTANDING THE CHARACTERISTICS OF IONOSPHERIC DISTURBANCES DUE TO GEOMAGNETIC STORM OF MOTHERS DAY 2024
(Mekelle University, 2025-01-21) Seid Eshetu
We studied ionospheric responses due to geomagnetic storms of mothers day 2024,on global scale to find the sources that triggered the ionospheric variations. In particular, we analyze the total electron content(TEC), averaged electric field (Ey) , solar wind velocity Vsw, Plasma Density (ρ),Plasma temperature (T),interplanetary magnetic field along z-axis (IMF- Bz), geomagnetic disturbance storm time index (Dst), and solar flux F10.7 index. A geomagnetic storm is a major disturbance of Earth’s magnetosphere that occurs when there exists an exchange of energy from the solar wind into the space environment surrounding Earth. The largest storms that result from these conditions are associated with coronal mass ejections (CMEs). The effects of all these all have an outcome of Magetospheric compression. That is , the sudden increase in solar wind speed and southward IMF Bz compressed the ionosphere, reducing the standoff distance of the magneto-pause. Magnetic reconnection allowed solar wind energy transfer efficiently into the magnetosphere, driving geomagnetic currents and accelerating charged particles. The sharp drop in Dst reflects a strengthened ring current, which forms as energetic particles circulate around earth. Enhanced electric currents flowing through the ionosphere caused joule heating, leading to the thermal expansion of the upper atmosphere. This can alter ionospheric density and composition, affecting satellite drag and radio wave propagation. Secondly, at mid latitudes, ionospheric storm Enhanced Densities (SEDs) are likely to have formed due to electric field -driven plasma transport from lower to higher latitudes. Thirdly, Southward IMF conditions and enhanced electric fields can generate ionospheric irregularities, such as plasma bubbles, which degrade GNSS navigation signals and radio communications. Lastly but not the least, increased particle precipitation due to magnetospheric disturbances enhanced auroral emissions in polar auroral regions, indicating energy deposition from the magnetosphere into the ionosphere.
THE CHALLENGES OF CHEMISTRY LABORATORY PRACTICES AND THEIR SOLUTIONS IN THE CASE OF CISTERCIAN MONASTERY MARIAM TSION SECONDARY SCHOOL, BOLE SUB CITY, ADDIS ABABA, ETHIOPIA
(Mekelle University, 2025-01-25) Zeray Welegerima
Chemistry laboratory practices are essential for reinforcing students' understanding of scientific concepts and developing critical practical skills. However, educational institutions in developing countries often encounter significant challenges in maintaining well-equipped and functional chemistry laboratories. This study investigates the challenges faced in chemistry laboratory practices at Cistercian Monastery Mariam Tsion Secondary School in Bole Sub City, Addis Ababa, Ethiopia, and explores feasible solutions to address these issues. A mixed-methods research approach was employed, incorporating both quantitative and qualitative data collection techniques. Surveys were conducted among chemistry teachers and students to assess their perceptions of the prevalent challenges. The findings indicate several key issues, including inadequate laboratory equipment and supplies, outdated or malfunctioning apparatus, limited laboratory space, and insufficient safety protocols. Additionally, challenges related to teacher training, student engagement, and overall laboratory management were identified. Based on these findings, the study proposes a multifaceted strategy to address these obstacles. Recommendations include securing funding for laboratory upgrades, implementing systematic equipment maintenance and replacement plans, providing extensive training for teachers and laboratory technicians, and improving student safety awareness and hands-on participation in laboratory activities. This study contributes to a broader understanding of the difficulties faced by secondary schools in developing countries in implementing effective chemistry laboratory practices. The proposed solutions offer valuable insights for policymakers, school administrators, and educational stakeholders in formulating strategies to enhance the quality of chemistry education and laboratory experiences for students.
EFFECT OF COOPERATIVE LEARNING ON STUDENTS’ ACADEMIC ACHIEVEMEN IN CHEMISTRY ON THE TOPICS OF CHEMICAL EQUILIBRIUM AND PHASE EQUILIBRIUM: THE CASE OF KELLEM PREPARATORY SCHOOL, KELLEMWOLLEGA ZONE, OROMIA REGIONAL STATE, ETHIOPIA
(Mekelle University, 2025-01-25) GUTA DEGU DISASA
The study investigate effects of cooperative learning on students’ academic achievement in chemistry on the topics of chemical equilibrium and phase equilibrium: The case of Kellem preparatory school, Kellem Wollega zone, Oromia regional state, Ethiopia. The study sampled 120 students from two sections one taken as experimental group and the other as control group which are purposively selected from six sections of Kellem Preparatory School grade 11 natural science because of relatively low score in chemistry. The data obtained from 60 students (M=29 and F=31) participated in cooperative learning instruction methods and 60 students (M=30 and F=30) participated in instruction based on regular learning methods, 2 School administrators and 2 Chemistry teachers. The research was used experimental methods, questionnaire and interview for data collection. Data analysis was done descriptively using mean, frequencies, percentages and t-test. A pre-test was administered before the study to identify students’ prior knowledge. Sample students score an average academically achievements 60.12% of control group (M=30.06% and F=30.06%) and 60.4% of experimental group (M=29.20% and F=31. 20%) before the treatment. A post- test was administered after cooperative learning instruction methods in order to examine the difference in achievements. In the comparison of the post –test of the two groups, the experimental groups were an average of 81.44 % (M=39.36% and F=42.08%) of academic achievements and 62.52% of control group (M=31.26% and F=31.26%) academic achievements in selected topic. The result of study show that cooperative learning instructional methods was better than the regular method of instructional methods in increasing students’ academic achievements and promote face to face interaction, creating positive dependence and insuring the active participation of all students in activities.
A Study of the Impact of Feedback-Integrated Continuous Assessment on Grade 12 Students’ chemistry achievement: The case of Medhanealem Preparatory School, Addis Ababa, Ethiopia
(Mekelle University, 2025-01-25) BIRUK GEMECHU ABEBE
Feedback is often overlooked in continuous assessment despite its potential to enhance student outcomes. This study examines the impact of feedback-integrated continuous assessment on Grade 12 students' chemistry achievement at Medhanealem Preparatory School in Addis Ababa. The study involved three groups: two experimental groups (one with feedback-integrated continuous assessment and one with continuous assessment without feedback) and one comparison group (traditional exercises and activities). A mixed-methods approach was used, combining quantitative (quasi-experimental) and qualitative (case study) data. Instruments included pre- and post-achievement tests and semi-structured interviews with teachers from the experimental groups. Data were analyzed using SPSS (version 26), applying One-way and Two way ANOVA, and Pearson Correlation tests to compare group scores. Post-test results revealed a statistically significant improvement in the experimental groups compared to the comparison group (p < 0.05). A significant relationship was also found between continuous assessment scores and post-test outcomes. Qualitative data from interviews and classroom observations highlighted that feedback-integrated continuous assessment positively influenced students' chemistry achievement. The study suggests that incorporating feedback into continuous assessment allows teachers to adapt instruction to better meet individual student needs, ultimately improving learning outcomes. Based on these findings, it is recommended that teachers design feedback-oriented assessments aligned with curriculum objectives and clearly communicate performance expectations to enhance student learning