Browsing by Author "Assefa, Dawit"

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    External Quality Assessment Performance and Associated Factors in Selected Governmental Clinical Bacteriology Laboratories in Ethiopia
    (Addis Ababa University, 2019-10) Assefa, Dawit; Woldie, Mistire(Dr.); Sisay, Abay (MSc.)
    Background: External quality assessments (EQA) at various level of the health system are very helpful in the identification of possible nonconformance in laboratory. Moreover, it helps develop guidelines for remedial actions to be taken for the improvement of laboratory services with ultimate goal of attaining better health care and patient outcome. Objective: To assess selected government clinical bacteriology laboratories external quality assessment performance and associated factors in Ethiopia from July 2018 up to May 2019. Methods: A cross sectional study design using both a prospective and retrospective data approach was employed among 16 bacteriology laboratories from July 2018 to May 2019. From One world accuracy PT sample provider they obtained seven panel tests: bacterial identification from sputum, blood, eye swab, wound and CSF; throat swab; urine; genital; N. gonorrhoea identification; gram stain; and AST. In addition, four standard bacterial strains were prepared in house and distributed to participant laboratories. Data were collected using pre-tested structured questionnaire as well as on-site observation. The collected data was cleaned and analyzed using Stata14.2 and exact logistic regression. P <0.05 was considered as statistically significant. Results: The overall failure rate of bacterial identification during event two from CSF, blood and Abdominal abscess, was 7/13(53.8 %); from throat culture 8/13(61.5%), from urine 5/13(38.46%), and from genital cultures 8/13(61.5%) from gram staining 7/15(46.6%) and for N. gonorrhea ID the failure rate was 2/14(14.2%). On the other hand, the failure rate from event three were: from sputum, blood and eye swab 14/16 (87.5 %), from urine 7/16(43.8%), from throat 8/15(53.3%), from genital culture 9/16(56.3%), from gram staining 5/16(31.3%) and for N.gonorrhoea ID the failure rate was 7/15(46.7%). The overall AST failure rate of the laboratories during event 2 and 3 were 8/10(80%), and 8/13(62%) respectively. Fifteen laboratories were participated in house prepared PT samples for bacterial ID and AST were the failure rate from pus 1/15(6.66%),sputum 3/15(20%),blood 5/15(33.3%),AST 1/15(6.66%) .The foremost identified contributing factories for unsuccessful PT results includes mis utilization of updated SOPs, no use of McFarland standard, unable to perform internal quality control for Gram staining, culture media, identification reagents, and antibiotic discs (p<0.05). Conclusion: The overall EQA performance of participant clinical bacteriology laboratories was poor. The main associated factors were poor implementation of quality management system such as poor records and documentation, poor internal quality control practices, no regular competency assessment, VII lack of refreshment on basic microbiology training Therefore, continues training and mentorship for laboratories participating in external quality assurance are mandatory.
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    Photonic Crystal: Principles and Aplications in Nanophotonics
    (Addis Ababa University, 2010-03) Assefa, Dawit
    Throughout the last two decades the studies on photonic crystal have made a tremendous developments in many aspects of physics, specifically in the field of nanophotonics. Moreover,many principles and applications of photonic crystal are appearing to be valid in different area of studies. Photonic crystals are microscopic dielectric materials by which light is to be trapped,confined or controlled as it tends to propagates through them. In this project, we review the historical development of photonic crystals, metalic photonic crystals and plasmoics, Maxwell equations and the inspirations of bandgap, the propagation of light in different media such as one , two and three dimensional media of photonic band gap materials(photonic crystals). Our study has fully, concentrated on the progresses, developments of principles and technological applications of photonic band gap material. Finally, we have predicted that electromagnetic waves( light modes) can be guided to a desired direction and in a desired manner carrying ample information by the help of different devices that appropriately exploit the properties of photonic crystals
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    Sample Survey on the Academic Performance of Addis Ketema Senior Secondary School Students in the Year 1990 E.C.
    (Addis Ababa University, 1999-06) Assefa, Dawit; Libsie, Mulugeta (PhD)
    Statistics is a theory of information with inference as its goal. The branch of statistics that best describes the above fact is sample survey. In sample survey, we often deal with the collection, organization and analysis of data to make inference. Sample survey makes it easier to study effects of various variables on the suhject matter of interest and making inferences based on the data which have been obt'1ined under th e study. In this paper, data have been collected on the academic performance of students of /\e!clis I<:etema Senior Secondary School on the basis of grades scoreci in the Eth iopian School Leaving Certificate Examination (ESLCE) by both the regular and extension (even ing) program students. This could be done by simple random sampling and stratified random sampling. In the analysis of the data, we will be dealing with estimation, cnmr"risons ane! h ~/ pothe s i s testing of different parameters. Main and r;n rn h;nod ef fect!:' of various variables such as effects of field of study and sex 01' !ll" rPlf ormance of students will also be analyzed. Fin." lIy. r:onr;/usions and recommenciations will be made.