Polymerase chain reaction (PCR) sequencing of specific viral gene segments was used to investigate the phylogenetic relationships among the orbiviruses. Sequence comparisons of the bluetongue virus (BTV) RNA3 from different regions of the world (North America, South Africa, India, Indonesian, Malaysia, Australia and the Caribbean region) showed that geographic separation had resulted in significant divergence, consistent with the evolution of distinct viral populations. There were at least 3 topotypes (Gould, 1987); the Australasian, African - American and another topotype represented by BTV 15 isolated in Australia in 1986. The topotypes of BTV had RNA3 nucleotide sequences that differed by approximately 20 per cent. Analysis of BTV-specific gene segments from animal and insect specimens showed that bluetongue viruses had entered northern Australia from South East Asia, possibly by wind-borne vectors. Nucleotide sequence comparisons were used to show the close genetic relationship between BTV 2 (Ona-A strain) from Florida and BTV 12 from Jamaica, and to investigate the reassortment of BTV genome segments in nature. The mutation rates of the BTV RNA2 and RNA3 segments were estimated to be of the order of 10(-4) nucleotide changes/site/year, similar in magnitude to that reported for other RNA viruses.

No description available.

We examine the structural complexities of a 28-km long part of the Clark fault of the San Jacinto fault zone in southern California in order to better document its lateral extent and the style of deformation of its southeast end. Changes in structural style are observed as the Clark fault’s damage zone widens from ~ 1-2 km in crystalline rocks of the Peninsular Ranges southeastward to ~ 18 km in the sedimentary rocks of the San Felipe-Borrego subbasin of the Salton Trough. The Clark fault extends into the San Felipe-Borrego subbasin as the Arroyo Salada segment for ~ 11-12 km to a newly defined northeast-trending structural boundary. This structural boundary, referred to herein as the Pumpkin Crossing block, is a ~ 3-km wide and ~ 8-km long fault zone dominated by northeast-striking sinistral-normal strike-slip faults. Southeast of the Pumpkin Crossing block the newly defined San Felipe Hills segment extends the Clark fault another ~12-13 km southeast to its intersection with the Extra fault zone. The Clark fault may have nearly 14.5-18 km of right separation represented in the surface deformation of the Arroyo Salada and San Felipe Hills segments, but the total amount of strain is masked by the wide diffuse fault zone with its complex deformation patterns and geometries. The lateral change observed in microseismicity patterns across the Arroyo Salada and San Felipe Hills segment boundary supports our structural interpretations about the existence, location, and structure of this boundary. Vertical patterns in the microseismicity suggest that the Clark fault zone narrows at depth, dips steeply northeast in the subsurface, and must interact with at least one weak decollement layer(s) beneath and/or with the sedimentary basin. Structural deformation within the late Miocene to Holocene silty- and clay-rich sedimentary basin of the Salton Trough includes features characteristic of strike-slip faults, such as stepovers, conjugate faults, folds, flower structures, and fault bends, as well as many unique structures that include pooch structures, ramp-flat geometries of strike-slip faults, complex en echelon fault zones with localized shear distributed across a high frequency network of faults, and heterogeneous kinematic indicators within individual fault zones.

No description available.

Technological advancement such as the increase in processing power, hard disk capacity and network bandwidth has opened up many exciting new techniques to synthesise sounds, one of which is Concatenative Sound Synthesis (CSS). CSS uses data-driven method to synthesise new sounds from a large corpus of small sound snippets. This technique closely resembles the art of mosaicing, where small tiles are arranged together to create a larger image. A ‘target’ sound is often specified by users so that segments in the database that match those of the target sound can be identified and then concatenated together to generate the output sound. Whilst the practicality of CSS in synthesising sounds currently looks promising, there are still areas to be explored and improved, in particular the algorithm that is used to find the matching segments in the database. One of the main issues in CSS is the basis of similarity, as there are many perceptual attributes which sound similarity can be based on, for example it can be based on timbre, loudness, rhythm, and tempo and so on. An ideal CSS system needs to be able to decipher which of these perceptual attributes are anticipated by the users and then accommodate them by synthesising sounds that are similar with respect to the particular attribute. Failure to communicate the basis of sound similarity between the user and the CSS system generally results in output that mismatches the sound which has been envisioned by the user. In order to understand how humans perceive sound similarity, several elements that affected sound similarity judgment were first investigated. Of the four elements tested (timbre, melody, loudness, tempo), it was found that the basis of similarity is dependent on humans’ musical training where musicians based similarity on the timbral information, whilst non-musicians rely on melodic information. Thus, for the rest of the study, only features that represent the timbral information were included, as musicians are the target user for the findings of this study. Another issue with the current state of CSS systems is the user control flexibility, in particular during segment matching, where features can be assigned with different weights depending on their importance to the search. Typically, the weights (in some existing CSS systems that support the weight assigning mechanism) can only be assigned manually, resulting in a process that is both labour intensive and time consuming. Additionally, another problem was identified in this study, which is the lack of mechanism to handle homosonic and equidistant segments. These conditions arise when too few features are compared causing otherwise aurally different sounds to be represented by the same sonic values, or can also be a result of rounding off the values of the features extracted. This study addresses both of these problems through an extended use of Artificial Intelligence (AI). The Analysis Hierarchy Process (AHP) is employed to enable order dependent features selection, allowing weights to be assigned for each audio feature according to their relative importance. Concatenation distance is used to overcome the issues with homosonic and equidistant sound segments. The inclusion of AI results in a more intelligent system that can better handle tedious tasks and minimize human error, allowing users (composers) to worry less of the mundane tasks, and focusing more on the creative aspects of music making. In addition to the above, this study also aims to enhance user control flexibility in a CSS system and improve similarity result. The key factors that affect the synthesis results of CSS were first identified and then included as parametric options which users can control in order to communicate their intended creations to the system to synthesise. Comprehensive evaluations were carried out to validate the feasibility and effectiveness of the proposed solutions (timbral-based features set, AHP, and concatenation distance). The final part of the study investigates the relationship between perceived sound similarity and perceived sound interestingness. A new framework that integrates all these solutions, the query-based CSS framework, was then proposed. The proof-of-concept of this study, ConQuer, was developed based on this framework. This study has critically analysed the problems in existing CSS systems. Novel solutions have been proposed to overcome them and their effectiveness has been tested and discussed, and these are also the main contributions of this study.

Étant donné un ensemble S de points du plan, une triangulation de S est une décomposition de l'enveloppe convexe de S en triangles dont les sommets sont les points de S. Une triangulation de S est dite de Delaunay si le cercle circonscrit à chaque triangle ne contient aucun point de S en son intérieur. Dans cette thèse, nous étudions une généralisation de ces notions à un ensemble S de segments disjoints du plan.<br />Nous commençons par définir une nouvelle famille de diagrammes, appelés triangulations de segments. Nous étudions leurs propriétés géométriques et topologiques et nous donnons un algorithme pour construire efficacement une telle triangulation.<br />Nous généralisons ensuite la notion de triangulation de Delaunay aux triangulations de segments et nous mettons en évidence la dualité avec le diagramme de Voronoï de segments.<br />Nous étendons également la légalité des arêtes au cas des triangulations de segments en définissant, d'une part, la légalité géométrique qui caractérise la triangulation de Delaunay de segments parmi l'ensemble de toutes les triangulations de segments possibles et, d'autre part, la légalité topologique qui caractérise les triangulations de segments qui ont la même topologie que celle de Delaunay.<br />Enfin, nous décrivons un algorithme de « flip » qui transforme toute triangulation de segments en une triangulation qui a la même topologie que celle de Delaunay. À l'aide de fonctions localement convexes, nous démontrons que la suite de triangulations construites par cet algorithme converge vers celle de Delaunay et nous prouvons qu'une triangulation de segments qui a la même topologie que celle de Delaunay est obtenue après un nombre fini d'étapes.

Le bribri est une langue chibcha parlée au Costa Rica (Amérique Centrale). Les langues chibcha représentent la principale famille de l’Aire Intermédiaire (Constenla 1991), qui relie la Mesoamérique aux zones amazonienne et andine. Ce sont cependant toutes des langues en danger, encore relativement peu décrites.Cette thèse est une analyse de la phonologie du bribri (Schlabach 1974 ; Wilson 1974 ; Constenla 1981 ; Jara 2004), problématisée autour de ses caractéristiques typologiques :(i) Le système nasal : le bribri fait partie des rares langues du monde dans lesquelles la nasalité n’est pas distinctive pour les consonnes. Les consonnes nasales présentes dans l’output sont le résultat d’harmonies nasales (Cohn 1993 ; Walker 1998, 2001) et d’hypervoisement par abaissement du voile du palais (Iverson & Salmons 1996 ; Solé 2009). Alors que le premier processus avait en partie été décrit pour le bribri (Wilson 1970 ; Constenla 1982, 1985 ; Tohsaku 1987), le second n’avait pas encore été identifié.(ii) La consonne /tk/ : une unité distinctive, combinant deux lieux, sans pour autant être une consonne doublement articulée, contrairement à ce qui avait précédemment été décrit (Lehmann 1920 ; Schlabach 1974 ; Wilson 1974 ; Constenla 1981 ; Jara 2004). Je propose de l’analyser comme une géminée modulée (contour segment, Sagey 1990).La présente étude s’inscrit dans la lignée des travaux qui considèrent que les structures phonologiques doivent être expliquées par des contraintes phonétiques, comme les travaux précurseurs d’Ohala (1975, 1981, 1983). J’utilise plus particulièrement le modèle de la Phonologie Articulatoire (Browman & Goldstein 1986, 1989). Les analyses s’appuient sur des données acoustiques, récoltées dans deux communautés bribri entre 2012 et 2014 (Bajo Coen - Coroma et Amubre).En plus d’une démarche typologique et phonétique, j’adopte une approche dialectale et diachronique, afin de mieux appréhender le système phonologique de la langue. / Bribri is a Chibchan language spoken in Costa Rica (Central America). Chibchan languages form the main family of the Intermediate Area (Constenla 1991), which links Mesoamerica to the Amazonian and the Andean regions. All of them are endangered and are still under described.This dissertation provides an analysis of Bribri phonology (Schlabach 1974; Wilson 1974; Constenla 1981; Jara 2004) problematized according to its typological characteristics:(i) The nasal system: Bribri is among the few languages in the world to lack distinctive nasal consonants. The nasal consonants present in the output result from nasal harmony (Cohn 1993; Walker 1998, 2001) and hypervoicing through velopharyngeal opening (Iverson & Salmons 1996; Solé 2009). While the first process has been partially described for Bribri (Wilson 1970; Constenla 1982, 1985; Tohsaku 1987), the second has not been individuated in the language.(ii) The consonant /tk/: the consonant /tk/ is a distinctive unit which combines two places of articulation. Contrary to what has been previously described (Lehmann 1920; Schlabach 1974; Wilson 1974; Constenla 1981; Jara 2004), it is not a doubly articulated consonant. I propose to analyse it as a contour geminate consonant (based on the concept of contour segment, Sagey 1990).Following Ohala’s pioneering work (1975, 1981, 1983), this work is based on the assumption that phonological structures must be explained by phonetic constraints. More specifically, I use the Articulatory Phonology frame (Browman & Goldstein 1986, 1989). The analysis is based on acoustic data collected among two Bribri communities, between 2012 and 2014 (Bajo Coen - Coroma and Amubre).Along the typological and phonetic approach, I have adopted a dialectal and diachronical point of view to better capture the phonological system of the language.

De plus en plus de chercheurs s'accordent à dire que la prosodie a un rôle crucial dans la communication, la compréhensibilité du discours et la détection d'un accent étranger. L'apprentissage et l'enseignement de l'anglais langue étrangère bénéficieraient ainsi à mettre au premier plan les traits suprasegmentaux, ou prosodiques (accent, rythme et intonation), plutôt que les traits segmentaux (consonnes et voyelles) comme le font beaucoup d'enseignants, d'autant que les erreurs prosodiques ont souvent un effet plus néfaste que les erreurs segmentales. Cette thèse de doctorat part de l'hypothèse que les francophones apprenant l'anglais pourraient davantage améliorer leurs capacités à l'oral (production et perception) si on leur enseignait avant tout les caractéristiques prosodiques de la langue cible, plutôt que de mettre en avant les segments. Notre étude expérimentale compare ainsi l'impact d'une approche « prosodique » avec l'impact d'une approche « segmentale » sur des apprenants français non-débutants. Bien que les deux méthodes d'enseignement aient permis aux participants de s'améliorer en production et perception L2, en comparaison avec un groupe de contrôle n'ayant pas reçu de cours, aucune des deux méthodes ne leur a permis d'améliorer leurs capacités à l'oral davantage que l'autre, ce qui montre l'importance tout aussi forte d'inclure les aspects segmentaux que suprasegmentaux dans l'enseignement de l'anglais langue étrangère. / Researchers increasingly highlight the crucial role of prosody in communication, speech comprehensibility, and the detection of a foreign accent. Thus, the learning and teaching of English as a foreign language would benefit from prioritising the suprasegmental, or prosodic, features (i.e., stress, rhythm, and intonation), rather than the segmental features (i.e., consonants and vowels) as many teachers tend to do, all the more so as prosodic errors often have a more detrimental effect than segmental errors. The present doctoral thesis starts from the hypothesis that French-speaking learners of English could improve their oral skills (production and perception) more if they were primarily taught the prosodic characteristics of the target language, rather than putting the segments in the foreground. Our experimental study compares the impact of a “prosody-based” teaching approach with that of a “segment-based” approach on non-beginner French learners of English. Although the two teaching methods enabled the participants to improve their L2 production and perception skills, compared with a non-treated control group, neither of the two methods enabled them to improve their oral skills more than the other, suggesting that it is important to include segmental and suprasegmental aspects alike in the teaching of English as a foreign language.

A frequency response tracer technique was used to study the hydraulic properties of a laboratory flow through reactor with variations in reactor size, flow rate and applied mixing. At any one set of conditions the reactor was studied over a range of input sine wave frequencies. Theoretical models consisting of in-series networks of completely mixed segments, plug flow segments, and dead space allowances were developed to approximate the experimental findings. / Thesis / Master of Engineering (ME)

No description available.