M.Ing. (Electrical and Electronic Engineering) / This dissertation presents a comprehensive electrical model of the human auditory periphery. The model focuses on the generation and transmission of otoacoustic emissions (OAEs) under biometric conditions. The auditory system model was divided and studied in three sections, namely the outer, middle and inner ear sections. Existing models were used and improved for the study. The outer ear model was derived using electroacoustic analogies. The middle ear model was derived empirically. The inner ear model was derived by relating the mechanical properties of the inner ear to electrical principles. The outer ear model includes an analog diffraction circuit and a linear transmission line representation of the auditory canal and the concha. The variation of the radius of the auditory canal along its length was incorporated when computing the model of the outer ear. A pair of second order polynomials were used to create a new radius-length function which approximates the relationship between the radius of the auditory canal and its length. The frequency response of the outer ear model obtained using the radius-length function gave a wide frequency range representation of the outer ear characteristics. The middle ear is modelled using an analog network. Only the linear operation region of the middle ear was considered, thus excluding its reflex nonlinear mechanisms, namely; the stapedius muscle action and the stapes clipping displacement. The influence of the middle ear on the transmission of OAEs was evaluated by considering both the forward and reverse transmission characteristics/path of the middle ear. The middle ear response demonstrated great sensitivity to changes in the terminal loads connected to the middle ear as well as the transformer ratio. The inner ear behavior is represented by means of a nonlinear transmission line model. The nonlinear mechanism of the outer hair cells, which are taken as the primary sources of OAEs, are modelled using nonlinear voltage sources. The inner ear model was evaluated for conditions of both the active and inactive outer hair cells voltage sources. Due to limitations in the simulation software, a reduced active inner ear model was computed.The influence of the number of segments of the inner ear was explored. A reduced inner ear model having 40 segments was found to be sufficient in representing the frequency characteristics of the inner ear, whilst preserving the frequency-latency relationship of OAEs. The study not only improved the model of the auditory periphery, but also suggested several factors that can be incorporated in future research in order to better design signal acquisition and processing methods for OAE biometric applications.

Traditionally, collegiate ear training classes in the United States are comprised largely of notation-based exercises and assignments, administered to small groups by a single teacher. Aside from the piano, instruments generally are not used during ear training classes, de-emphasizing the perceived correlation between students' aural skills development and their progress as instrumentalists. By studying the history of music education, and examining current aural skills pedagogy, the author has found that common practice often relies on notation-based tasks as a measurement of success, despite the fact that research supports the effectiveness of aural-based learning. In order to encourage a better understanding of pitches and rhythms, the author composed fifteen original etudes ("Ear-tudes") for tuba with accompanying drills. Before revealing each Ear-tude, the instructor leads the student through related drills. Each of the Ear-tudes focuses on a particular interval, scale-type, rhythmic, or tonal challenge, within a variety of meters, tempi, and styles, all of which are suitable for the typical first year tuba student. This method provides an innovative way for tuba teachers to integrate ear training into their instruction, alongside a new collection of etudes designed specifically for freshman students.

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1) Test the accuracy of the Welch Allyn Microtympanometer against standard tympanometry. 2) Correlate preoperative clinical findings with: • Microtympanometry • Standard tympanometry 3) Assess influence of induction by gas anaesthesia on: • Post-induction microtympanometry • Intraoperative myringotomy findings 4) Assess the practicality of using the Welch Allyn Microtympanometer as a screening tool in Pre-School audiological testing.

Research aimed at optimizing diagnostic laboratory procedures is central to the development of effective bovine viral diarrhoea virus (BVDV) control programmes. BVDV is a single-stranded RNA virus that crosses the placenta to infect foetuses resulting in reproductive losses due to foetal death or persistently infected (PI) calves that usually die early in life. Persistently infected animals are widely accepted to be the primary reservoir of BVDV and the largest source of BVDV infection. Persistently infected animals that survive calfhood are at risk of developing mucosal disease in later life which is a severe and usually fatal condition. In addition, persistently infected calves that become replacement heifers in the herd may experience significant morphological changes that occur in the ovaries which can result in impaired reproductive performance. This poses important challenges to overall animal/herd health and causes losses to the cattle industry. Long-term storage of bovine ear notch samples from calves persistently infected (PI) with BVDV may affect the ability of diagnostic assays to efficiently detect the virus. This study assessed the effects of 1) long-term storage of formalin-fixed samples at room temperature to detect BVD viral antigen with the aid of immunohistochemistry (IHC), 2a) long-term storage of fresh ear notch samples kept at -20°C, and 2b) long term storage of phosphate-buffered saline (PBS) ear notch supernatant kept at -20°C on the ability of an antigen-capture ELISA (AC-ELISA) to detect viral antigen. Previous studies have verified 100% sensitivity for both AC-ELISA on ear notch supernatant and immunohistochemical testing of ear notches to detect BVDV provided that samples are properly collected and stored. In this study, ear notch samples from seven animals were subjected to prompt formalin fixation and fresh samples to prolonged storage at -20°C. Frozen ear notches and ear notch supernatant yielded positive results on AC-ELISA for the duration of the study, i.e. 6 months, and OD values remained significantly within range. There was no significant difference between storing fresh ear notch samples and PBS ear-notch supernatant at -20°C. However, positive IHC staining on formalin-fixed ear notches started to fade away between day 17 and day 29 when stored at room temperature. We conclude that fresh ear notches could safely be stored at -20°C for a period of 6 months for detecting BVD viral antigen at a later stage. Copyright / Dissertation (MSc)--University of Pretoria, 2009. / Veterinary Tropical Diseases / unrestricted

The ear and eye are both special sensory organs that are derived from the neural ectoderm and develop closely together during the fourth week of embryogenesis. The structure of these organs is related to their functions and therefore each of the components must be able to effectively operate in order to function efficiently. The role of genetic and environmental factors that affect the development of both the ear and eye have been identified and studied, which allows researchers to better understand the association of the ear and eye. Currently, there are syndromes (such as Goldenhar and CHARGE) that are known to affect both systems concurrently. However, there is a possibility that there are more undiscovered syndromes that also affect the ear and eye simultaneously, where there are still unexplored associations between various eye and ear disorders. Identifying and understanding these syndromes allows clinicians to better diagnose and treat patients who originally present with one or the other disorder and have not been further tested. The ear and eye have also been associated with the central nervous system, where disorders in the systems might indicate neurodevelopment or neurological issues because of abnormalities in the development of their common origin.

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第18168号 / 医博第3888号 / 新制||医||1003(附属図書館) / 31026 / 京都大学大学院医学研究科医学専攻 / (主査)教授 伊藤 壽一, 教授 大森 治紀, 教授 影山 龍一郎 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第20255号 / 医博第4214号 / 新制||医||1020(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 渡邉 大, 教授 萩原 正敏, 教授 影山 龍一郎 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

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