Browsing by Author "Berhanu, Samuel"

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    Chromosome Study of Some Grasshopper Species from Different Localities in Central Ethiopia
    (Addis Ababa University, 2010-12) Berhanu, Samuel; Dagne, Kifle (PhD)
    Hitherto, around 200 grasshopper species have been recorded in Ethiopia. Despite the diversity and economic importance of Ethiopian grasshoppers, the available information on their taxonomy, distribution and ecology is meager, and no report on the karyology of Ethiopian grasshoppers is available prior to this study. In this study, the karyotypes of ten taxa identified to different taxonomic levels are described. The studied grasshopper specimens were identified to belong to two families – Acrididae and Tetrigidae. Under Acrididae six genera – Acanthacris, Paracinema, Gastrimargus, Acrotylus, Pardalophora and Acrida were identified. Specimens of two additional taxa could not be identified beyond the family level. The specimens under the family Tetrigidae were found to belong to genus Paratettix. The grasshopper specimens were collected from eight localities in central Ethiopia. Chromosome preparations were made from tissues of the whole gut, 6 – 8 hours after the colchicine injection. The tissue was grinded in hypotonic solution (0.075M KCl). The suspension was centrifuged and the pellet was fixed in 3:1 methanol:acetic acid and followed by centrifugation. Air dry slide preparations were made from cell suspension. In some case the testis was used for the preparation of meiotic chromosomes following the same steps as in mitotic chromosome preparation. Slides were stained in Giemsa stain. Basically, all the studied species (Acanthacris spp., Paracinema tricolor, Gastrimargus spp., Acrida spp.-1, Acrida spp.-2, Acrotylus spp., Pardalophora spp., and the two unidentified specimens) belonging to the family Acrididae showed similarity in their karyotype, with all of them having 2n = 23 (22 autosomes + X) and 24 (22 autosomes + XX) telocentric chromosomes in male and female, respectively. Paratettix spp. (family Tetrigidae) had a different chromosome number, that is, 2n = 20 telocentric chromosomes. Furthermore, Acanthacris spp. showed some numerical instability of chromosomes in the mitotic and meiotic cells, and B chromosome like body was found in the meiotic cells of this specimen. Apart from the gross Karyotypic resemblance shown among the studied taxa of family Acrididae, slight variations in their karyotype have been noted between taxa of acridid grasshoppers. Further studies of the chromosomes of Ethiopian grasshoppers covering a wider geographic area and employing new cytological techniques were recommended. Keywords or phrases: Karyology, Central Ethiopia, Acridid grasshopper, Karyotypic conservatism, chromosome
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    Designing a Generic Web Information Architecture for Information Exchange and Interoperability of the Ethopian E-Commerce Logistics Sector
    (Addis Ababa University, 2020-06-06) Berhanu, Samuel; Meshesha, Million (PhD)
    The complexity of transport and logistics chains these days needs a fast and reliable information exchange system to ensure an efficient and cost optimized logistics solutions. To this end, standardizing and automating information flow of logistics chain is needed for a more transparent and optimized services. Intermodal logistics connections are becoming more commonplace and complex involving many business actors in the process, transnational scope, and multimodal logistics stages. The objective of this research is to design a generic web Information Architecture (IA) to promote information exchange among the various e-Logistics stakeholders. The research was carried out using design science research. TOGAF was also used as a designing framework to identify entities in the IA. Both primary and secondary sources were used for data collection. Key information sources were selected from logistics companies that are involved in the logistics supply chain on the basis of TOGAF under the umbrella of DSR methodology. The challenges and practices identified during the research were mainly the absence of standardized and interoperating information exchanging platforms, which in turn forces companies to operate disjointedly, the lack of standardized and reliant information exchanging process, planning and implementation was confirmed by the interviews and other documentations i.e. literature reviews and companies’ business forms and registers. This has become an impediment on the quality of data, security issues at different levels. This necessitates the design of a generic Information Architecture, which is web based platform to exchange data among the involved logistics actors. Therefore, this research attempts to undertake the design of generic Web Information Architecture. The architecture has covered all the information required regarding the Logistics Supply chain such as transportation warehousing management and operations processes. The proposed prototype was demonstrated to the logistics firms and evaluated by experts from five logistics firms out of the ten the study was conducted. The evaluation outcome revealed that 94.1% of the specialists have confidence in the proposed IA which they deem to be appropriate, to improve information exchanging practice in the logistics chain. However, one major challenge the experts raised is the issue, how the standardized IA can materialize to simplify information exchange of the industry, which in turn necessitates attention of all stakeholders to step forward.