Ethiopian Journal of Education and Sciences

The First Ground-Based Measurement of Atmospheric Carbonyl Sulphide over Addis Ababa (Ethiopia)

2020-11-11T21:00:19+00:00

Measurement of Carbonyl sulphide is very crucial to estimate the sulfur budget and is used as a tracer for the carbon cycle. Its simultaneous consumption with CO2 during photosynthesis by plant uptake makes it an ideal candidate for the partitioning of photosynthesis from respiration. This research provides the first ground-based abundance of OCS from a high-resolution Fourier Transform Infrared spectrometer over Addis Ababa (9o1’N, 38o76’E, an altitude of 2443 m.a.s.l.). We used PROFFIT95 to retrieve the vertical profile, average tropospheric and stratospheric mixing ratios, and column amount from the solar absorption spectra of OCS. Analysis of random and systematic error to retrieval shows that the total error contribution due to atmospheric and auxiliary parameters is less than 10%. The tropospheric and stratospheric average VMR in our site is 0.488 ppbv and 0.230 ppbv, respectively, with deviation from the global mean by 2.4% for tropospheric mixing ratio. The hourly variation of OCS particularly on 14, March 2010 shows slight accession from mid-morning to noon and reduction in the afternoon with a change in VMR of 0.019 ppbv. The tropospheric volume mixing ratio (in the unit of parts per billion by volume) and total column amount time series result from May 2009 to April 2010 show seasonal variation with maximum (0.60) in May and June, and minimum (0.37) in December and January. The total column amount reaches up to 8.5X1019 molecules/m2. The correlation between stratospheric tropopause level and the accession of stratospheric OCS level during hot season worth detail investigation to understand the variation of OCS besides taking long term measurement for trend analysis.

Education for Borena Pastoralist Community Children in Ethiopia: Practices and Challenges

2020-11-11T21:03:08+00:00

The study attempted to examine the practices and challenges of education for Borena pastoralist communities' children. The theoretical conception of the study is rooted in 'education as a right for the children' and the 'indigenous epistemology' perspectives. The concurrent nested strategy of mixed research design with data collected from multiple sources using multiple tools has been used. Results of the study indicated that the pastoralist community members see schooling in terms of the livestock possession and herding: where schooling children means losing livestock and losing the livestock means losing the very self of the community. The community adopted various adult-centric solutions such as rotational enrollment and turn-based attendance which are not commensurate with the children’s right concerns. The opportunity cost of schooling tended to define it all. Children's right to education is not even part of the discourse. The finding implicates that there is a need to diversify the education delivery approach and pay attention to the relevance of the system to the pastoralist community. Education development should be conceptualized within the broader pastoralist area development agenda. And children's right to education need to be popularized among the pastoralist community.

Block Procedure for Solving Stiff First Order Initial Value Problems Using Chebyshev Polynomials

2020-11-11T21:07:30+00:00

In this paper, discrete implicit linear multistep methods in block form for the solution of initial value
problems was presented using the Chebyshev polynomials. The method is based on collocation of the
differential equation and interpolation of the approximate solution of power series at the grid points.
The procedure yields four consistent implicit linear multistep schemes which are combined as
simultaneous numerical integrators to form block method. The basic properties of the method such as
order, error constant, zero stability, consistency and accuracy are investigated. The accuracy of the
method was tested with two stiff first order initial value problems. The results were compared with a
method reported in the literature. All numerical examples were solved with the aid of MATLAB
software after the schemes are developed using MAPLE software and the results showed that our
proposed method produces better results.

Variations in Tasting Phenylthiocarbamide (PTC) in Selected Individuals from Ethiopia: Implications for Human Health

2020-11-11T21:11:05+00:00

The present study aimed to examine the PTC tasting ability in selected individuals from Ethiopia. It involved 465 participants representing four ethnic groups. A total of 69 individuals from Amhara (30 females and 39 males), 52 from Agnuak (3 females and 49 males), 59 from Nuer and 285 (60 females and 225 males) from Oromo were recruited. The investigation was made using a series of graded concentrations of PTC dissolved in pure water and the results were recorded. The participants were analyzed for the distribution of tasters and non-tasters for PTC. The frequency of dominant and recessive alleles of PTC gene was calculated using Hardy-Weinberg methods. The result showed that the frequency of tasters (82.80%) were significantly higher than that of non-tasters (17.20%) in all populations. Likewise, frequency of tasters among males (83.06%) and females (82.61%) were significantly higher than the frequency of non-taster males (16.94%) and females (17.39%). This shows that PTC tasting ability varies as a function of sexes. In all populations, the frequency of T allele (0.59) is higher than the frequency of t allele (0.41). Recognition threshold for PTC in 465 participants of both sexes were determined (at 8 and 9 solutions) and indicated that the taste ability distribution is bimodal. Based on the present data on diet, an association between the ability to taste PTC and food preferences have been observed among the studied populations. With this regard, further comprehensive study on various populations is needed, which could have significant public health importance.

Tetracyclic Triterpenes from the Stem Bark of Vernonia biafrae and Evaluation of its Antimicrobial Activity

2020-11-11T21:16:37+00:00

In the search for bioactive metabolites from Ethiopian medicinal plants, two tetracyclic triterpenes; spinasterol (1) and shionone (2) along with cetyl alcohol (3) were isolated from the acetone extract of the stem bark of Vernonia biafrae, a medicinal plants widely used for the treatment of infectious diseases. Column chromatographic separations and Sephadex LH-20 gel filtration were employed for the isolation of the pure compounds. The compounds were characterized by spectrometric (NMR and mass) analyses and comparison with literature data. This is the first report of compound 2 and 3 from the genus Vernonia. The extracts and the isolated compounds were evaluated for their antimicrobial activities against both bacterial and fungal test strains and exhibited comparable activities with the standard antibiotics. The highest activity was observed for acetone extract (23.73 0.10 mm) and compound 2 (23.72 0.30 mm) against Staphylococcus aureus. Whereas, the rest showed moderate to low inhibitory activities against the test strains. The finding could be used for comprehensive evaluations of the phytochemicals for their microbial activities and also support the claim that the plant V. biafrae is used for the treatment of microbial diseases.

Typology and Structure of Basic-level Activities in Afaan Oromoo

2020-11-11T21:20:54+00:00

In this study, we examined the typology and structure of basic-level activity, which is one of the five eventuality types (the others being stative, achievement, semelfactive and accomplishment) in Afaan Oromoo. Accordingly, we use the three temporal features (dynamicity, durativity and atelicity) and verb constellations of clauses to identify and describe each subclass of the situation aspect. These are claimed to denote the state-of-affair based on perceptual and cognitive abilities. Purposive sampling technique was used to collect data from written web corpora of different genres. These corpora were developed by The HaBit Project and Ethiopian Language Technology Group in 2016. Afaan Oromoo textbooks of grades 9-12 were also used as data sources. On the assumption that activities are dynamic, durative and atelic which imply no inherent final points, we have identified five subcategories: motion, emission, consumption, creation and active perception. The verbs in these subtypes of activities co-occur with agentive, non-agentive and self-agentive arguments to show various semantic readings. Regarding logical structure, we have proposed [DO’ (x, [Pred’ (x) or (x, y)])] as the general logical structure of the situation. In the structure, the prime DO’ represents the logical operator, Pred’ is to any activity verb, ‘x’ is agent, effector or experiencer, and ‘y’ is a theme, patient or stimulus. However, ‘x’ is the theme for one-place predicates. From the findings, we suggest that the computational aspect of logical and argument structures should be formulated to advance Afaan Oromoo a step towards natural language processing technology.

Determination of Selected Pesticide Residues in Diga Water Reservoir, Eastern Wollega Zone, Ethiopia

2020-11-11T21:24:40+00:00

This study aimed to assess the status of diazinon, chlorothalonil, Malathion and chloropyrifos in Diga water reservoir, located in Diga district, Eastern Wollega Zone, Ethiopia. It serves as Nekemte City municipal tap water reservoir. Salting-out assisted liquid-liquid extraction (SAALE) was used for extraction and/or preconcentration of the target analytes before their determination by gas chromatography mass spectrometry (GC-MS). The method showed acceptable linearity (R2) in the range of 0.996 to 0.999. The limit of detection (LOD) of the method ranged from 1.38 to 4.92 μg L−1and limit of quantification (LOQ) ranged from 4.60 to 16.40 μg L−1. The relative recovery ranged from 80.34 % to 100.32%. Analysis of the collected real samples indicates that the water samples were not polluted with residues of diazinon, chlorothalonil, Malathion and chlorpyrifos or contain below the LOD of the method.