Not available

Not available / text

The vocal folds are important for protection of the airway during swallowing, the regulation of breathing and for voice production. Unilateral vocal fold paralysis (UVP) is caused by damage to the recurrent laryngeal nerve (RLN). Although surgery is most often linked to onset of UVP, the cause remains unknown in 12-42% of those with this disorder [1, 2]. At the level of the aortic arch the RLN branches from the vagus nerve and courses around the arch to ascend back toward the larynx. I hypothesize that an aneurysm of the aorta or alternatively changes in aortic arch compliance could impose increased stress and strain on the RLN where it is adjacent to the aorta resulting in impaired nerve function. The purpose of this research is to develop a computational model based on the biomechanical properties of the left RLN. This model is important for formulating predictions of the typical ranges of stress and strain responses of RLN tissue to forces imposed by surrounding structures (aortic arch). These predictions may be important for future investigations using an animal model to determine the amount of stretch necessary to cause onset of UVP. The first aim of this work was to identify differences in the biomechanical properties in the RLN of piglets between its location within the neck and the portion of the left RLN within the thorax, including the aortic arch region. The distal right RLN segment showed higher maximum tangential modulus (MTM) than the left. With the left nerve the proximal segment (aortic arch region) exhibited higher values of MTM and the stiffness parameter β than the distal segment. This increased stiffness of the proximal region may be in response to the pulsatile forces near the region of the aortic arch. The second aim of this work was to identify difference in the biomechanical properties in adolescent and piglet RLN specimens, between age and between the proximal and distal segments. Additionally the collagen structure of the RLN was imaged with two-photon microscopy to compare the microstructure with the biomechanical response of the RLN tissue. The tangential modulus (TM) and full width half maximum of the collagen fiber distribution (FWHM) was larger in the proximal segments than the distal segments. The strain energy and stiffness parameter α were larger in the piglet than the adolescent pigs while the stiffness parameter β was larger in the adolescent pigs. The purpose of the third aim was to use the material constants from the second aim to create a parametric computational model of the left RLN and the aortic arch. Results indicated that the parameters with the greatest sensitivity to left RLN maximum principal stress and strain are the material properties of the aortic arch. The maximum value of strain found in the RLN region of interest was 16.1%, which may indicate that some combination of aortic arch and RLN properties can elicit damage in the RLN.

While much research exists on self-efficacy in music programs, few research studies have qualitatively examined the impact of vocal performance settings on music education majors' self-efficacies and career goals. This collective case study examines the self-efficacy perceptions of four undergraduate vocal music education students in five vocal performance and rehearsal settings: (a) voice lessons, (b) studio classes, (c) choral rehearsals, (d) choral performances, and (e) juries. During a spring semester at a major university in the southwestern United States, I examined how participants' perceptions of their family backgrounds, career goals, lifestyles, peers, and student-teacher relationships influenced their vocal self-efficacy perceptions and music career goals. Data collection included observations, individual interviews with participants, and one focus group interview. Coding methods were used to analyze the interview transcripts and observation field notes. Triangulation, peer review, and member checks of transcriptions were used to ensure accuracy. Findings are documented case-by-case and as cross-case themes. I found that mastery experiences and family support during adolescence influenced participants' initial decisions to major in music but had little influence on vocal self-efficacy during the study. Secondly, self-efficacy changes noted throughout the study influenced participants' career goals. Other emergent themes included the role of memory, teacher feedback, concept comprehension and socialization. I conclude with cross-case themes and offer ideas for future self-efficacy research.

This is an interpretive study of the life of the Prophet Muhammad as it is artistically depicted in the repertoire (especially the narrative ballads) of fifty-one contemporary Egyptian maddahin (singers of eulogies in honour of the Prophet Muhammad, sing. maddah). The elements of this repertoire, as diverse as narrative ballads, classical odes, Qur'an chanting, and the melodies of the secular songs of well-known Egyptian singers, do not exist as discrete units but rather as a lively tawlifa (blend)--to use a common term in Colloquial Egyptian Arabic (CEA). This study is about blends where discrete units lose their borderlines and leak into one another, about phenomena which are "betwixt and between" the perceived scholarly categories which confidently delineate boundaries between elite and popular Islam, the historical and the legendary Muhammad, the sacred and the profane, orality and writing, standard and colloquial Arabic. / In order to understand the process which marks the making of the people's Muhammad, the study deals with the sources and the contents of the repertoire of the Egyptian maddahin. The performance of these singers as well as their interaction with the audience are also considered. The "legendary" material in this repertoire is attested as historical by many authoritative and well-recognized "orthodox" authors of the past. Classical Arabic, classical poetic forms, philosophical notions, long believed to be the exclusive possessions of the learned, are freely utilized in the ballads and popular songs under study. The people's Muhammad appears as both a commanding figure, empowered by the supernatural, and a touchingly vulnerable human being; God's ascetic messenger and a man who savours life's lawful pleasures; an eloquent speaker who utters Qur'an-like terse Arabic and a lovingly familiar figure who also uses local patois. Bipolarity, beloved of many scholars, is seriously challenged by the art of the Egyptian maddahin. A renewed effort has to be made to discover more valid categories which will take into account the intermediary combinations (Mischbildungen) characteristic of that art.

Modern scholars have suggested various approaches to the analysis of the pretonal repertory. However, if we consider the question of how the individual voice parts interact in a Renaissance polyphonic composition to create coherence for the movement as a whole, we find that there are no tools available to undertake such a task. We may be able to speak generally of the arrival of certain moments as relatively accented or unaccented; we may even be able to dissect a complete melodic line with some segmentation process to highlight motivic structure, phrase development or contour-articulated pitch events. But there are no analytic strategies available yet which are capable of disclosing the structures of independent voice parts and their interaction as timepoint-accenting elements capable of creating formal, rhythmic and pitch-class patterns. This study outlines a methodology that has been developed to deal with these specific issues. The analytic strategy is based on the perception of accents in individual voices of polyphonic works. The types of accents germane to Renaissance polyphony include durational, leap, contour, cadential and beginning-accents. The study proposes a simple, bipartite classification of accentual strength—strong or weak. Each voice part in a work is then analyzed, with every pitch attack represented as strongly or weakly accented through special notation developed for the analysis. The methodology affords a picture of the most strongly- accented timepoints in the individual melodies of three- and four-voice cantus firmus masses of the mid- to late fifteenth century. The relative strengths of these accents, along with their synchronization in the multi-voice aggregate, are disclosed through the notation. After renotating scores with this special notational symbology, we extract points of coincident strong accents in three or more voices to create accent profiles for each section of a movement. We then compare profiles of same-texted works by different composers in order to disclose normative formal and pitch-class procedures in some Renaissance compositions.

No description available.

No description available.

No description available.

Producing an accurate model of the human voice has been the goal of researchers for a very long time, but is extremely challenging due to the complexity surrounding the way in which the voice functions. One of the more complicated aspects of modelling the voice is the fluid dynamics of the airflow, by which the process of self-oscillation of the vocal folds is sustained. This airflow also provides the only means by which the ventricular bands (two vocal fold-like structures located a short distance above the vocal folds) are driven into self-oscillation. These have been found to play a significant role in various singing styles and in voice pathologies. This study considers the airflow and flow-structure interaction in an artificial up-scaled model of the human larynx, including self-oscillating vocal folds and fixed ventricular bands. As the majority of any significant fluid-structure interaction takes place between structures found within the larynx, this thesis is limited only to examining this component of the voice organ. Particle Image Velocimetry (PIV) has been used to produce full field measurements of the flow velocity for the jet emerging from the oscillating vocal folds. An important advance in this study is the ability to observe the glottal jet from the point at which it emerges from the vocal folds, thus permitting a more complete view of the overall jet geometry within the laryngeal ventricle than in previous work. Ensemble-averaged PIV results are presented for the experimental model at different phase steps, both with and without ventricular bands, to examine their impact on the dynamics of the human larynx and the glottal jet. Finally, the three-dimensional nature of the glottal jet is considered in order to further understand and test currently held assumptions about this aspect of the jet dynamics. This was achieved by undertaking PIV in a plane perpendicular to that already considered. It is shown that the ventricular bands have an impact on the flow separation point of the glottal jet and on the deflection of the jet centreline. Furthermore, the dynamics of the vocal folds alters when ventricular bands are present, but the glottal jet is found to exhibit similar three-dimensional behaviour whether or not ventricular bands are present.