Browsing by Author "Assefa, Daniel"

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    Amharic Speech Training for the Deaf
    (Addis Ababa University, 2006-08) Assefa, Daniel; Midekso, Dida (PhD)
    It has been believed that all deaf persons can not make edible sound and can only communicate through Sign Language. However, Deaf people can make voices and communicate orally unless they are mute by nature. With speech training it is possible for the Deaf to learn how to speak and “listen”. Speech training can be given manually with a human trainer but it is a very tiresome task and its’ demands are more than the capability of trainers. The solution proposed for this problem is an automated speech training system which is already implemented for different languages. This thesis addresses a similar solution but for Amharic language. Due to the limitations of special equipment and software tools we can get we proposed modeling of a lip for the articulation of Amharic characters which is part of an automated speech training system. We used an Analysis-Synthesis approach to first analyze a real lip in speech making and applied the output of the analysis on our lip model to articulate different Amharic characters. The solution proposed is implemented in a prototype developed for selected Amharic characters and its efficiency is tested with some students of Mekanissa Deaf School. Keywords: Speech Training, Sign Language, Deaf Education, Lip modeling, Talking Head
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    Amharic Speech Training for the Deaf
    (Addis Ababa University, 2006-08) Assefa, Daniel; Midekso, Dida (PhD)
    It has been believed that all deaf persons can not make edible sound and can only communicate through Sign Language. However, Deaf people can make voices and communicate orally unless they are mute by nature. With speech training it is possible for the Deaf to learn how to speak and “listen”. Speech training can be given manually with a human trainer but it is a very tiresome task and its’ demands are more than the capability of trainers. The solution proposed for this problem is an automated speech training system which is already implemented for different languages. This thesis addresses a similar solution but for Amharic language. Due to the limitations of special equipment and software tools we can get we proposed modeling of a lip for the articulation of Amharic characters which is part of an automated speech training system. We used an Analysis-Synthesis approach to first analyze a real lip in speech making and applied the output of the analysis on our lip model to articulate different Amharic characters. The solution proposed is implemented in a prototype developed for selected Amharic characters and its efficiency is tested with some students of Mekanissa Deaf School. Keywords: Speech Training, Sign Language, Deaf Education, Lip modeling, Talking Head
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    Identification and Functional Aspects of Protein Kinase Activity in Leishmania Aethiopica
    (Addis Ababa University, 1993-08) Assefa, Daniel; Skoglund, Goran (PhD); Worku, Yesehak (PhD)
    Protein kinase activity was demonstrated on intact Leishmania aethiopica promastigotes but not on heat generated "amastigotes". Similar work conducted on lysed cells revealed enzyme activity in soluble and particulate fraction of flagellated parasites. Enzyme on intact cell plasma membrane preferred Histone V-S over protamine as in vitro substrate whereas enzyme from soluble or particulate fraction of lysed cells displayed the reverse in vitro preference. On the other hand enzymes from both intact and lysed cells were inhibited by Staurosporine and Formycin ATP. Incubation of intact stationary phase parasites with t 2pJ ATP led to phosphorylation of eight protein bands. Similar experiment conducted using lysed cells revealed twenty bands. Incubation of the cells with [32pJ with the assumption of generating intracellular t2 P ] ATP also led to a patte111 of phosphorylation similar to that of lysed cells. It follows from the above that Leishmania aethiopica promastigotes possess both extra and intracellular endogenous substrates of protein kinases. Measurement of soluble kinase activity revealed increased activity as cells went from log to stationary phase where intact cell activity remained constant. Exposure to elevated temperature (37') induced transformation of the promastigotes to aff/agellated organism "amastigotes". This transformation resulted in a potent down regulation of both the soluble 'and the ecto kinase activities. In the promastigotes, Staurosporine caused morphological alterations. On the other hand Formycin ATP had a profound inhibitDlY effect on thymidine incorporation and cellular proliferation. These effects of Formycin ATP do not seem to be wholly accounted by its protein kinase inhibitory activity. A classical protein kinase C like activity could not be detected in the promastigotes. However, evidence for the probable presence of a phorbol ester insensitive, calcium and phospholipid independent protein kinase C is presented. All the same these observations do not rule out the presence of more than one subclass of protein kinases. This work suggests that major protein kinase activities may be involved in the regulation of proliferation, development and adaptation to "hostile" environment of Leishmania aethiopica promastigotes. It also argues that the continued study of key events in the biology of this organism is cTilcial in the development of better therapeuticstrategies.