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Abstract Background Linkage disequilibrium (LD) is commonly measured based on the squared coefficient of correlation $$\left({r}^{2}\right)$$ r 2 between the alleles at two loci that are carried by haplotypes. LD can also be estimated as the $${r}^{2}$$ r 2 between unphased genotype dosage at two loci when the allele frequencies and inbreeding coefficients at both loci are identical for the parental lines. Here, we investigated whether $${r}^{2}$$ r 2 for a crossbred population (F1) can be estimated using genotype data. The parental lines of the crossbred (F1) can be purebred or crossbred. Methods We approached this by first showing that inbreeding coefficients for an F1 crossbred population are negative, and typically differ in size between loci. Then, we proved that the expected $${r}^{2}$$ r 2 computed from unphased genotype data is expected to be identical to the $${r}^{2}$$ r 2 computed from haplotype data for an F1 crossbred population, regardless of the inbreeding coefficients at the two loci. Finally, we investigated the bias and precision of the $${r}^{2}$$ r 2 estimated using unphased genotype versus haplotype data in stochastic simulation. Results Our findings show that estimates of $${r}^{2}$$ r 2 based on haplotype and unphased genotype data are both unbiased for different combinations of allele frequencies, sample sizes (900, 1800, and 2700), and levels of LD. In general, for any allele frequency combination and $${r}^{2}$$ r 2 value scenarios considered, and for both methods to estimate $${r}^{2}$$ r 2 , the precision of the estimates increased, and the bias of the estimates decreased as sample size increased, indicating that both estimators are consistent. For a given scenario, the $${r}^{2}$$ r 2 estimates using haplotype data were more precise and less biased using haplotype data than using unphased genotype data. As sample size increased, the difference in precision and biasedness between the $${r}^{2}$$ r 2 estimates using haplotype data and unphased genotype data decreased. Conclusions Our theoretical derivations showed that estimates of LD between loci based on unphased genotypes and haplotypes in F1 crossbreds have identical expectations. Based on our simulation results, we conclude that the LD for an F1 crossbred population can be accurately estimated from unphased genotype data. The results also apply for other crosses (F2, F3, Fn, BC1, BC2, and BCn), as long as (selected) individuals from the two parental lines mate randomly.

Abstract Background The traditional way to estimate variance components (VC) is based on the animal model using a pedigree-based relationship matrix (A) (A-AM). After genomic selection was introduced into breeding programs, it was anticipated that VC estimates from A-AM would be biased because the effect of selection based on genomic information is not captured. The single-step method (H-AM), which uses an H matrix as (co)variance matrix, can be used as an alternative to estimate VC. Here, we compared VC estimates from A-AM and H-AM and investigated the effect of genomic selection, genotyping strategy and genotyping proportion on the estimation of VC from the two methods, by analyzing a dataset from a commercial broiler line and a simulated dataset that mimicked the broiler population. Results VC estimates from H-AM were severely overestimated with a high proportion of selective genotyping, and overestimation increased as proportion of genotyping increased in the analysis of both commercial and simulated data. This bias in H-AM estimates arises when selective genotyping is used to construct the H-matrix, regardless of whether selective genotyping is applied or not in the selection process. For simulated populations under genomic selection, estimates of genetic variance from A-AM were also significantly overestimated when the effect of genomic selection was strong. Our results suggest that VC estimates from H-AM under random genotyping have the expected values. Predicted breeding values from H-AM were inflated when VC estimates were biased, and inflation differed between genotyped and ungenotyped animals, which can lead to suboptimal selection decisions. Conclusions We conclude that VC estimates from H-AM are biased with selective genotyping, but are close to expected values with random genotyping.VC estimates from A-AM in populations under genomic selection are also biased but to a much lesser degree. Therefore, we recommend the use of H-AM with random genotyping to estimate VC for populations under genomic selection. Our results indicate that it is still possible to use selective genotyping in selection, but then VC estimation should avoid the use of genotypes from one side only of the distribution of phenotypes. Hence, a dual genotyping strategy may be needed to address both selection and VC estimation.

The first COVID-19 case was reported in Ethiopia on 13th March 2020 and series of announcements of set of measures, proclamation and directives have been enacted to fight the coronavirus pandemic. These have implications for the regular health services including the TB control program. This brief communication assesses the impact of the COVID-19 response on the TB control activities of Addis Ababa health centers based on research project data. We compared the patient flows in pre-COVID-19 period (quarter 1, Q1) and during COVID-19 (quarter 2, Q2 and quarter 3, Q3) of 2020 at 56 health centers in Addis Ababa from all 10 sub-cities per sub-city. The patient flow declined from 3,473 in Q1 to 1,062 in Q2 and 1,074 in Q3, which is a decrease by 62-76% and 52-80% in Q2 and Q3 respectively as compared to that of Q1. In Q2, Kolfe keranio and Kirkos sub-cities recorded the biggest decline (76 and 75% respectively) whereas Yeka sub-city had the least decline (62%). In Q3, Kirkos sub-city had the biggest decline (80%) and Addis ketema sub-city had the lowest (52%). We conclude that the series of measures, state of emergency proclamation and government directives issued to counter the spread of COVID-19 and the public response to these significantly affected the TB control activities in Addis Ababa city as attested by the decrease in the patient flow at the clinics. Health authorities may inform the public that essential health services are still available and open to everyone in need of these services.

INTRODUCTION: Incidence of adverse drug reactions (ADR) associated with antiretroviral therapy (ART) was higher in developing countries. In two teaching hospital in Ethiopia: Debremarkose 23% and Yirgalem 73.2% of study participants reported at least one ADR. Since there was limited information about ADR in the study area; we aimed to determine its incidence-rate and predictors. METHODS: we conducted retrospective cohort study using medical records of HIV-infected patients enrolled on ART between 2006 and 2017 in government hospitals of Ethiopia. ADR was defined as report of at least one unwanted response to ART. We run descriptive and cox regression analysis (CRA). RESULTS: incidence-rate of ADR was 4.1 per 100 person-years (py). Hazards of ADR among patients living at rural was almost two times than at urban; [Adjusted hazard ratio (AHR): 1.94(95%(CI):1.18, 3.20)]. Stavudine (D4T)-Lamivudine(3TC)-Nevirapine(NVP) had about two times [AHR: 1.78(95%CI:1.03, 3.08)], Zidovudine (AZT)-3TC-NVP had about two times [AHR: 2.34(95%CI: 1.20, 4.57)], D4T-3TC-Efaviranze (EFV) had about three times [AHR: 2.86 (95%CI: 1.38, 5.95)] and AZT-3TC-EFV had about two times [AHR: 2.16(95%CI: 1.21,3.90)] hazards of ADR than Tenofovir(TDF) based regimens. Being WHO clinical stage III had about two times hazard of ADR [AHR: 2.46 (95%CI: 1.22, 4.95)] and IV had about four times hazard of ADR [AHR: 4.32 (95%CI: 1.88, 9.93)] than stage I. CONCLUSION: risk of ADR was higher among adult HIV-infected patients on ART living in rural, WHO clinical stage III and IV, and patients on AZT and D4T based regimen. AZT should not be given as an alternative treatment, increase access of TDF regimens.

INTRODUCTION: Cholera outbreaks in Nigeria are often associated with high case fatality rates; however, there is a dearth of evidence on context-specific factors associated with the trend. This study therefore aimed to identify and quantify the factors associated with cholera-related deaths in Nigeria. METHODS: Using a cross-sectional design, we analysed surveillance data from all the States that reported cholera cases during the 2018 outbreak, and defined cholera-related death as death of an individual classified as having cholera according to the Nigeria Centre for Disease Control case definition. Factors associated with cholera-related death were assessed using multivariable logistic regression and findings presented as adjusted odds ratios (ORs) with 95% Confidence Intervals (95% CIs). RESULTS: Between January 1 and November 19, 2018, 41,394 cholera cases were reported across 20 States, including 815 cholera-related deaths. In the adjusted multivariable model, older age, male gender, living in peri-urban areas or in flooded states, infection during the rainy season, and delay in seeking health care by >2 days were positively associated with cholera-related death; whereas living in urban areas, hospitalisation in the course of illness, and presentation to a secondary hospital were negatively associated with cholera-related death. CONCLUSION: Cholera-related deaths during the 2018 outbreak in Nigeria appeared to be driven by multiple factors, which further reemphasises the importance of adopting a multisectoral approach to the design and implementation of context-specific interventions in Nigeria.

INTRODUCTION: birth defects are the most serious cause of infant mortality and disability in sub-Saharan African countries with variable magnitude. Hence, this study was aimed to determine the pooled prevalence of birth defects and its associated risk factors among newborn infants in sub-Saharan African countries. METHODS: a total of 43 eligible studies were identified through literature search from Medline (pub med), EMBASE, HINARI, Google scholar, Science Direct, Cochrane Library and other sources. Extracted data were analyzed using STATA 15.0 statistical software. A random effect meta-analysis model was used. RESULTS: twenty-five studies in 9 countries showed that the pooled prevalence of birth defects was 20.40 per 1,000 births (95% CI: 17.04, 23.77). In the sub group analysis, the highest prevalence was observed in southern Africa region with a prevalence of 43 per 1000 (95% CI: 14.89, 71.10). The most prevalent types of birth defects were musculo-skeletal system defects with a pooled prevalence of 3.90 per 1000 (95% CI: 3.11, 4.70) while the least was Down syndrome 0.62 per 1000 (95% CI: 0.40, 0.84). Lack of folic acid supplementation (95% CI: 1.95, 7.88), presence of chronic disease (95% CI: 2.00, 6.07) and intake of drugs (95% CI: 3.88, 14.66) during pregnancy were significantly associated with the birth defects. CONCLUSION: the prevalence of birth defects is relatively high with high degree of regional variabilities. The most common types of birth defects were musculoskeletal defects. Lack of folic acid supplementation, presence of chronic disease and intake of drugs during pregnancy were significantly associated with birth defects.

Abstract Background A breeding program for commercial broiler chicken that is carried out under strict biosecure conditions can show reduced genetic gain due to genotype by environment interactions (G × E) between bio-secure (B) and commercial production (C) environments. Accuracy of phenotype-based best linear unbiased prediction of breeding values of selection candidates using sib-testing in C is low. Genomic prediction based on dense genetic markers may improve accuracy of selection. Stochastic simulation was used to explore the benefits of genomic selection in breeding schemes for broiler chicken that include birds in both B and C for assessment of phenotype. Results When genetic correlations ($$r_{g}$$ rg ) between traits measured in B and C were equal to 0.5 and 0.7, breeding schemes with 15, 30 and 45% of birds assessed in C resulted in higher genetic gain for performance in C compared to those without birds in C. The optimal proportion of birds phenotyped in C for genetic gain was 30%. When the proportion of birds in C was optimal and genotyping effort was limited, allocating 30% of the genotyping effort to birds in C was also the optimal genotyping strategy for genetic gain. When $$r_{g}$$ rg was equal to 0.9, genetic gain for performance in C was not improved with birds in C compared to schemes without birds in C. Increasing the heritability of traits assessed in C increased genetic gain significantly. Rates of inbreeding decreased when the proportion of birds in C increased because of a lower selection intensity among birds retained in B and a reduction in the probability of co-selecting close relatives. Conclusions If G × E interactions ($$r_{g}$$ rg of 0.5 and 0.7) are strong, a genomic selection scheme in which 30% of the birds hatched are phenotyped in C has larger genetic gain for performance in C compared to phenotyping all birds in B. Rates of inbreeding decreased as the proportion of birds moved to C increased from 15 to 45%.

This paper considers the implications of digital text production models for the development of reading materials for emergent and early readers in the Ethiopian context. We draw from several theoretical frameworks and also from comments of Ethiopian academics, writers, and publishers to ground descriptions of Ethiopian contexts of language and literacy. We then present three different models for the production and curation of digital stories for children and contemplate how these models align with existing literacy traditions and practices. We also raise questions about the potential effects on the development of literary culture and children’s literature in Ethiopia of projects aimed at rapidly producing large corpora of literature for children. Ultimately, we pose complicated cultural and linguistic questions that need to be taken into consideration to provide appropriate and original early literacy materials in Ethiopia.

Increases in mean air temperature are thought to improve productivity in northern forests but site-specific observations have shown that high temperatures can have deleterious effects. This study reconstructs leaf area index (LAI) time series for the Great Lakes–St. Lawrence forest region of Ontario using SPOT vegetation optical satellite data and the University of Toronto v2 LAI algorithm to study the impact of a spring heatwave in 2010. The results indicate a decline in 2010 LAI values as compared to prior normal years (2006–2009), coincident with the onset of high spring temperatures, which lasts throughout the growing season. Fitting a linear mixed model shows a significant link between high temperatures and LAI declines throughout the study area. These results provide the first evidence of sustained declines in LAI, and by proxy productivity, following high spring temperatures at the landscape scale.

INTRODUCRION: Suspected cholera cases were reported to the city administration health bureau in Addis-Ababa, Ethiopia on June 5, 2016 and it was laboratory confirmed by culture on 7 June 2016. The outbreak was declared by the government on June 8, 2016. The aim of this study was to rapidly investigate the outbreak epidemiologically and guide response activities in the affected Sub cities of Addis Ababa city administration.

INTRODUCTION: more than 20 million infants were born with low birth weight in worldwide. Low birth weight contributes more than 80 percent of all the neonatal mortality. In Ethiopia, studies have shown that there is a high prevalence of low birth weight among newborns. Thus, this study was aimed to determine the magnitude and associated factors with low birth weight among newborns delivered at term in Kambata-Tembaro zone, Southern Ethiopia, 2018. METHODS: institution based cross-sectional study design was used. The sample size was proportionally allocated to each hospital. The total of 341 study participants was enrolled using systematic random sampling techniques. Data were collected by interview-administered questionnaire and entered using Epi-Info version-7 and exported to SPSS version 20 for analysis. Multivariate logistic regression analysis was carried out to identify associated factors with the low birth weight. RESULTS: the prevalence of low birth weight was 18% and significantly associated with the mothers non-employment [aOR=5.4;95%CI:1.7-17.4], residing in the rural [AOR=5.4; 95%CI:2.1-14.7], unintended pregnancy [aOR=2.0;95%CI:1.2-3.8], not attending antenatal care [aOR=2.3;95%CI: 1.3-2.7], mothers with greater than three births [aOR=1.5;95% CI:1.8-2.6], birth interval less than or equal to two years [aOR=1.9;95%CI:1.6-3.6] and intimate partner violence during pregnancy [aOR=2.1:95% CI: 1.1-3.9]. CONCLUSION: the study finding shown that the prevalence of low birth weight among newborn was high (18%) in the study. Preventing of low birth weight is an important intervention to reduce neonatal death. Therefore, maximizing women economic status, providing quality family planning services, enabling pregnant women to use antenatal care and preventing intimate partner violence during pregnancy via launching women empowering strategies in the community level is highly recommend.

INTRODUCTION: Mortality of adult patients who are on antiretroviral therapy (ART) is higher in low-income than in high-income countries. After the failure of standard first-line treatment, patients switch to second-line regimens. However, there are limited data about the outcome of patients after switching to a second-line regimen in the study area. This study aimed to measure the rate of mortality and its determinants among HIV patients on second-line ART regimens. METHODS: multicenter institution based retrospective follow up study was conducted among 1192 adult patients who started second-line ART between 2008 and 2016 in eight selected hospitals of Amhara region. Patients who started second-line treatment after the failure of first-line treatment were included. Patient medical records, registration books, and computer database were used to collect the data. Time to death after a switch to second-line ART was the primary outcome of interest. Cox proportional hazard model was fitted to identify determinant factors of mortality. RESULTS: among 1192 patients who were on second-line ART, 136 (11.4 %) died with 3,157 person-years of follow up. Over the study period, the mortality rate was 4.33 per 100 person-years. Not taking isoniazid preventive therapy (IPT) (Adjusted Hazard Ratio (AHR): 6.6; 95 % CI: 2.9, 15.0), did not make modification on second-line regimen (AHR: 4.4; 95% CI: 2.8, 6.8), poor clinical adherence (AHR: 2.5; 95% CI: 1.4, 4.5), functional status of bedridden (AHR: 2.7; 95% CI: 1.5, 4.8), and having attained a tertiary level of education (AHR: 0.4; 95% CI: 0.2, 0.8) were independent determinants of mortality. CONCLUSION: the incidence rate of mortality was high and most of the deaths occurred within 12 months after switching to second-line ART. Higher mortality among adult HIV-infected patients was associated with poor adherence, no formal education, not taking IPT, being bedridden at the time of the switch, and not modifying second-line treatment. Improving treatment adherence of patients by providing consistent adherence counseling, providing INH prophylaxis and monitoring patient's regimen more closely during the first twelve months after switch could decrease mortality of HIV patients on a second-line regimen.

INTRODUCTION: Rotavirus causes severe-diarrheal diseases in infants. An estimation of 138 million rotavirus-associated diarrheal cases and 215,000 deaths occur every year globally. In December 2016, West-Shewa zone in Ethiopia reported unidentified gastrointestinal diarrhea outbreak. We investigated to identify the causative agent of the outbreak to support response operations. METHODS: Medical records were reviewed, and the daily line list was collected from health facilities. Descriptive data analysis was done by time, person and place. Stool specimens were first tested by antigen capture enzyme immunoassay (EIA) technique and further confirmed by reverse-transcription polymerase chain reaction (RT-PCR) as a gold standard. The product of RT-PCR was genotyped for each gene using G1-G4, G8-G9 and G12 primers for VP7 gene and P(4), P(6), P(8) and P(14) primers for VP4 gene. RESULTS: A total of 1,987 diarrheal cases (5.7 per 1000) and five deaths (case-fatality rate 0.25%) were identified and epidemiologically-linked to confirmed rotavirus from December 2016 to February 2017. Among the cases, 1,946 (98%) were 5 children. Fourteen (74%) of the 19 tested stool specimens were positive for rotavirus by EIA and RT-PCR. Majority of strains detected were G12P(6) (25%) and G-negative P(8) (25%) followed by G9P(8) (19%), G1P(8) (13%) and G3/G2 P(8), G12P(8), and G-negative P(6) (6% each). CONCLUSIONS: Diarrheal outbreak which occurred in West-Shewa zone of Ethiopia was associated with rotavirus and relatively more affected districts with low vaccination coverage. Routine rotavirus vaccination quality and coverage should be evaluated and the surveillance system needs to be strengthened to detect, prevent and control a similar outbreak.

Boron/epoxy laminates are used in aircraft and space vehicles for their high strength. Evaluation of stresses and residual strength of the laminate with square cutout are not analyzed in the literature. The present work is focused on studying the effect of hole orientation and laminate geometry on Boron/Epoxy composites laminates under in-plane loading. The analytical solution for stresses around holes in laminates is derived using Savins’s complex variables method to consider a multilayered plate with different hole shapes and orientations of loading. The basic equations of failure criteria available for plain laminates are derived to calculate the residual strength of the laminates with hole using the stresses obtained from the analytical solution. The derived analytical solution is validated by reproducing exactly the same results of earlier researchers even by other formulations and also by the results of finite element analysis using ANSYS. The [0/0]s laminate is not preferred due to highest stress concentrations at the corners that range between 12 to 12.45. Similarly, [45/-45]s laminate is also not preferred due to its higher values of stress concentrations which range from 9.5 to 28. The normalized stress for [0/90]s under x-axis loading is 9.6 and for y-axis loading it is 9.5 which is almost the same. Even for equi-biaxial loading, it is 8.5 and for shear loading, it is 12.45. Except for shear loading, [0/90]s laminate seems to be a better choice for a reasonable value of stress concentration for any general case loading. The analytical solution derived in the present work is the most general and unique as it can yield the stresses around any shape of hole and laminate geometry and all types of in plane loading. This solution will be able to reproduce the results of all other solutions available in the literature by different formulations.

Background: To my knowledge, there was no systematic study so far that analysed the extent of the impact of improved sanitation on infant mortality in the African context with long years of full-fledged longitudinal data. Aim: The aim of this study was to empirically examine the extent to which improved sanitation explains the observed differences in infant mortality under 5 years of age across African countries. Setting: The study covered a panel of 33 countries from north, south, east, west and central Africa for the years 1994–2013. Methods: The study first conducted Durbin–Wu–Hausman specification test and then used fixed effect model. In addition, Praison–Winsten regression with corrected heteroscedasticity was employed to verify the consistency of the results that were revealed in using fixed effect estimation method. Results: The study revealed that a 1% increase in access to improved sanitation would reduce infant mortality by a rate of about two infant deaths per 1000 live births. Also, the study confirmed that a significant decline in infant mortality rate was highly linked to improvements in education, health and sustainable economic growth. Conclusion: The findings have wide implications especially for African countries for which decreasing infant mortality is one of the most crucial priorities in the continent to reverse the current deep-rooted challenges related to human capital formation.

INTRODUCTION: Survival is low among non-treated patients. The time to survive after ART initiation has not been adequately studied. Thus, this study was aimed to determine survival status and associated factors among HIV positive adults on antiretroviral treatment in Debre Markos Referral Hospital, Northwest Ethiopia. METHODS: Facility-based retrospective cohort study design was conducted from September to February 2013. Data were collected from 640 patients' registration card in Debre Markos Referral Hospital who enrolled for treatment from 2005 to 2013. Kaplan-Meier survival curves and Log-Rank test were used to compare the survival times of different groups of patients. RESULTS: A total of 640 patients followed for median of 58 months and 261 patients died during the follow up period. Over all estimated mean survival times of patients was 65.22 (95%CI: 61.409-69.043) months after initiation of treatment. Baseline hemoglobin 10g/mm3, (AHR=1.869, 95%CI: 1.319-2.649), baseline ambulatory functional status (AHR=2.727, 95%CI: 1.905-3.905), bedridden functional status (AHR=2.382, 95%CI: 1.326-4.279), baseline WHO staging III and IV (AHR=2.164, 95%CI: 1.101-4.258), recent ART adherence (AHR: 2.169, 95%CI: 1.030-4.567) and fair adherence (AHR=1.887, 95%CI: 1.081-3.295) were associated with survival of the patients. CONCLUSION: The Kaplan-Meier results showed that the general mean estimated survival time of patients after Highly Active Anti Retroviral Therapy (HAART) initiation was improved. But low baseline hemoglobin, ill-health functional status, poor ART adherence were negatively associated with lesser survival of patients.

INTRODUCTION: in Ethiopia information on the level of utilization of the long term and permanent contraceptivemethods and associatedfactorsis lacking. The aim of this study was to understand the determinant factors of long acting and permanent contraceptive methods use among married women of reproductive age in Western Ethiopia. METHODS: a community based cross- sectional study design was employed. Multi stage sampling was used to select 1003 study participants. Data was collected from April 10 to April 25,2014 using a pre- tested structured questionnaire. The data were entered using Epi-info version 3.5.1 and exported to SPSS version 20 for analysis. Multivariate logistic regression analysis was done to identify predictors of long acting and permanent contraceptive methods at 95% CL. RESUSLTS: use of long acting and permanent contraceptive methods in this study was found to be 20%. Survey results showed a significant positive association between utilization of long acting and permanent contraceptive methods andwomen's education (AOR=1.72, 95%CI = 1.02 - 3.05), women's occupation (AOR = 2.01, 95% CI = 1.11 -3.58), number of live children (AOR = 2.42, 95% CI: 1.46- 4.02), joint fertility related decision (AOR = 6.11, 95% CI: 2.29- 16.30) ,having radio/TV (AOR = 2.31, 95% CI: 1.40 - 3.80), and discussion with health care provider about long acting and permanent contraceptive methods (AOR = 13.72, 95% CI: 8.37 - 22.47). CONCLUSION: efforts need to be aimed atwomen empowerment, health education, and encouraging open discussion of family planning by couples.

Friction is the resisting force between two bodies having relative motion. These bodies can be solid surfaces, fluid films or elements sliding against each other. There are many devices used to overcome sliding friction which include wheels and bearings. Ball bearings are used in many high speed and high precision machine tools because of their high productivity. A Crank-Rocker four bar mechanism consists of 4 linkages and 4 nodes. These nodes perform complex motions especially the coupler-rocker joint. In order to reduce the friction between these relatively moving links, ball bearings can be introduced. The coupler-rocker bearing oscillates about some axis as well as the raceways have some relative motion. Heat generation rate is not known for bearings performing this type of complex motion. This paper describes the mathematical modelling and thermal analysis of coupler-rocker bearing. Heat generation in the bearing can be estimated using this model. This can be countered by having proper lubrication and speed of bearing.

INTRODUCTION: In Ethiopia up to 60% of the current disease burden is attributable to poor sanitation. Latrine facility coverage is increasing since Health Extension Program started, whereas less attention to quality and utilization of latrine facilities in rural Ethiopia. METHODS: A community based cross-sectional study design with multistage sampling technique was employed to collect data from total of 806 households. RESULTS: A total of 801 households with latrines were assessed for their latrine utilization status. The extent of latrine utilization among 490 (61.2%) households was satisfactory. Presence of ≤5 children (AOR: 0.379, 95% CI :( 0.196, 0.732)), job of mothers (being farmer) (AOR: 0.321, 95%CI :( 0.136, 0.757)) and rare cleaning frequency (AOR: 0.055, 95% CI :( 0.005, 0.620)) were a factor negatively associated with latrine utilization. Whereas the presence of secondary school children (AOR: 3.739, 95% CI (1.884, 7.419), educational status of mothers (AOR: 2.437, 95% CI (1.032, 5.756), latrine constructed for the second time (AOR: 2.676, 95% CI :( 1.352, 5.299)), presence of door (AOR: 3.201, 95% CI: (1.437, 7.130)), the hygienic condition of latrine (AOR: 4.327, 95% CI: (2.05, 9.134)) were factors positively associated with latrine utilization. CONCLUSION: Latrine utilization rate of household latrines was satisfactory. The presence of ≤ 5 years children, job of mother (farmer), educational status of mothers, presence of secondary school student, the presence of the door, frequency of latrine construction, and hygienic condition of latrine were significant predictors of latrine utilization.

Supersonic separator is a new technology with applications in hydrocarbon dew pointing and gas dehydration which can be used to condensate and separate water and heavy hydrocarbons from natural gas. Many researchers have studied the design, performance and efficiency, economic viability, and industrial applications of these separators. The purpose of this paper is to succinctly review recent progress in the design and application of supersonic separators and their limitations. This review has found that while several aspects of this study are well studied, considerable gaps within the published literature still exists in the areas such as turndown flexibility which is a critical requirement to cater for variation of mass flow and since almost all the available designs have a fixed geometry and therefore cannot be considered suitable for variable mass flow rate, which is a common situation in actual site. Hence, the focus needs to be more on designing a flexible geometry that can maintain a high separation efficiency regardless of inlet conditions and mass flow variations. This review is focusing only on the design and application of the supersonic separators without going through the experimental facilities, industrial platform, pilot plants as well as theoretical, analytical, and numerical modelling.

During fluid flow from larger to smaller diameter pipes, a drop in pressure is experienced. High pressure drop across bit indicated high energy loss in the hydraulic system and also a setback to ROP performance. This is inefficient and pressure pumps would have to be of bigger sizing to make up for the losses. Present form of pressure drop models is in terms of mud density, flow rate, and total flow area. The objective of this paper is focused on the analysis of CFD simulation and to propose optimized parameters for improved ROP. Single phase flow study of Yield Power Law mud rheology was simulated at bottom hole of horizontal section. Parametric study on mud rheology was carried using DOE. Design points of DOE were sampled mostly using Latin Hypercube Sampling and a few by Central Composite Design. It is found that Kriging Response Surface method generated the best regression model where the predicted values are closest to the observed values and has the lowest Maximum Relative Residual (0.000336%). Inlet velocity and Power Index have significant effect on pressure drop. Consistency Index showed moderate effect while Yield Stress showed small effect to pressure drop. This research has proven that pressure loss model should take into account of mud rheology. Further research can be done with PDC bit rotation and its effect on mud behaviour.

Gas turbine (GT) engines are known for their high availability and reliability and are extensively used for power generation, marine and aero-applications. Maintenance of such complex machines should be done proactively to reduce cost and sustain high availability of the GT. The aim of this paper is to explore the use of autoregressive (AR) models to predict remaining useful life (RUL) of a GT engine. The Turbofan Engine data from NASA benchmark data repository is used as case study. The parametric investigation is performed to check on any effect of changing model parameter on modelling accuracy. Results shows that a single sensory data cannot accurately predict RUL of GT and further research need to be carried out by incorporating multi-sensory data. Furthermore, the predictions made using AR model seems to give highly pessimistic values for RUL of GT.