Paronychia virginica Spreng. (Caryophyllaceae) is a perennial evergreen herb of exposed, relatively xeric habitats. Approximately 10 mid-Appalachian populations remain in Virginia, West Virginia, and Maryland and are disjunct from populations located primarily in Texas, Oklahoma, and Arkansas. A study was conducted to test the hypothesis that eastern and western populations differ significantly and, therefore, represent at least two distinct taxa. Statistical analyses of 8 qualitative and 24 quantitative morphological characters indicated very highly significant (P < 0.001) variation between eastern and western populations of P. virginica. Characters differing most significantly included sepal pubescence, awn length, awn pubescence, awn curvature, length-width ratio of leaves, and shape of leaf apices. Starch gel electrophoresis was performed and six enzyme systems/nine loci (EST-2, EST-3, LAP, MDH-1, MDH-2, PGI, PGM-1, PGM-2, and SKDH) were identified as being consistently scorable and informative. Although gene flow between populations of P. virginica was shown to be restricted (mean FST = 0.353), populations are maintaining relatively high levels of genetic diversity. Genetic variability was quantified for each population and mean values for number of alleles per locus (A), percent loci polymorphic (P), and expected heterozygosity (HEXP) were found to be 1.95, 47.22%, and 0.204, respectively, exceeding those values reported for seed plants, widespread species, and endemic species. Hierarchical F statistics suggest higher levels of genetic variability within individual populations than among populations, regardless of geographic location. All statistically significant (P < 0.05) deviations from Hardy-Weinberg equilibrium indicated a deficiency in heterozygotes at the respective loci. Considering results from both the morphometric and allozyme analyses, the current author suggests recognizing two distinct subspecies, P. virginica subsp. virginica in the eastern U.S. and P. virginica subsp. scoparia in the south-central U.S. Conservation efforts should be focused on the maintenance of existing populations in both eastern and western regions of the U.S. in order to preserve the genetic and evolutionary potential of these taxa. / Master of Science

Heteroponerinae Bolton (2003) compreende três gêneros de formigas: Acanthoponera Mayr, Aulacopone Arnol\'di e Heteroponera Mayr. Acanthoponera é exclusivamente Neotropical, enquanto Heteroponera mostra uma distribuição disjunta nas Américas e Oceania. O gênero Aulacopone, de posição incerta na subfamília, é conhecido por uma única espécie representada por um par de rainhas coletadas por volta da década de 1930 em duas localidades no sudoeste da Ásia (Azerbaijão). O presente estudo representa a primeira revisão taxonômica global de Heteroponerinae em nível específico e a primeira tentativa de se analisar as relações filogenéticas internas da subfamília com base em caracteres morfológicos externos de todos os táxons nela incluídos. O estudo dos terminais utilizados na análise filogenética resultou em uma matriz com 101 caracteres, sendo 50 destes empregados pela primeira vez em uma análise cladística envolvendo formigas. A análise filogenética demonstra a monofilia de Heteroponerinae, com pelo menos quatro sinapomorfias sustentando esta hipótese. Os gêneros Acanthoponera e Heteroponera também são monofiléticos em todas as topologias aqui encontradas. As relações internas apontam para uma posição basal do gênero paleártico Aulacopone, que figura como grupo-irmão do clado Acanthoponera + Heteroponera. Ainda assim, devido à falta de caracteres que ofereçam maior suporte à inclusão de Aulacopone em Heteroponerinae, este gênero é mantido como incertae sedis na subfamília. A relativa falta de resolução nas relações internas em Acanthoponera e nos ramos mais apicais de Heteroponera não impede o reconhecimento de algumas linhagens como evolutivamente independentes. A presença destas linhagens em pelo menos duas regiões biogeográficas e a proximidade filogenética encontrada entre grupos neotropicais e australianos revelam um interessante cenário biogeográfico a ser investigado. Após o exame de 33 dos 36 espécimes-tipo designados para as espécies e subespécies de Heteroponerinae, seis espécies são reconhecidas para o gênero Acanthoponera, das quais duas são descritas como novas. Heteroponera apresenta 21 espécies (seis delas descritas aqui pela primeira vez), sete das quais restritas à Região Australiana (três novas) e 14 exclusivamente neotropicais (três novas). Heteroponera flava Kempf é sinonimizada sob H. panamensis (Forel) e H. georgesi Perrault passa a ser sinônimo júnior de H. microps Borgmeier. Indivíduos de castas e sexos ainda não registrados (incluindo machos, gines e operárias) são aqui descritos pela primeira vez para diferentes espécies de Heteroponerinae. Novos registros de localidades expandem significativamente a distribuição conhecida para a maior parte das espécies. Observações de campo aliadas a dados de rótulo de espécimes de museus fornecem importantes informações adicionais acerca da história natural do grupo. Larvas de Heteroponerinae são predominantemente predadoras, alimentando-se de pequenos artrópodes coletados pelas operárias. Ocasionalmente, adultos podem se alimentar dos líquidos (hemolinfa) resultantes das feridas provocadas no tegumento das presas caçadas por operárias e de exudatos vegetais no caso de espécies arborícolas. Os ninhos de Heteroponera são encontrados no solo ou na vegetação e podem abrigar colônias com algumas dezenas a poucas centenas de indivíduos, sendo que as operárias forrageiam preferencialmente no solo. Acanthoponera nidifica e forrageia exclusivamente em árvores. Com relação à estratégia reprodutiva, algumas espécies de Heteroponera podem apresentar gines ergatóides dividindo a função reprodutiva com as gines aladas na mesma colônia, enquanto em outras espécies as gines aladas foram completamente substituídas por ergatóides. Como uma próxima etapa para a compreensão da história evolutiva deste grupo sugere-se uma análise das relações internas dos gêneros através de ferramentas moleculares e um estudo dos padrões biogeográficos de Heteroponerinae. / Heteroponerinae Bolton (2003) comprises three ant genera: Acanthoponera Mayr, Aulacopone Arnol\'di and Heteroponera Mayr. Acanthoponera is exclusively Neotropical, while Heteroponera shows a disjunct distribution in the Americas and Australia. The position of Aulacopone within the subfamily is uncertain as it is known by a single species represented by two gynes collected around the 1930s in two localities in Southeast Asia (Azerbaijan). This study represents the first comprehensive taxonomic revision of Heteroponerinae at specific level and the first attempt to analyze the internal phylogenetic relationships of the subfamily based on the external morphology of all heteroponerine taxa. The study of the species used in the phylogenetic analysis resulted in a matrix with 101 characters, of which 50 are used for the first time in a cladistic analysis involving ants. The phylogenetic analysis demonstrates the monophyly of Heteroponerinae with at least four synapomorphies supporting this hypothesis. The genera Acanthoponera and Heteroponera are also monophyletic in all topologies found here. The internal relationships indicate a basal position of the paleartic genus Aulacopone, which appears as sister group to the clade Acanthoponera + Heteroponera. Due to the lack of characters to provide robust support to the inclusion of Aulacopone within Heteroponerinae, this genus is considered as incertae sedis in the subfamily. The relative low resolution of the internal relationships in Acanthoponera and in the apical branches of Heteroponera does not prevent the recognition of evolutionarily independent lineages. The presence of these lineages in at least two biogeographic regions and the phylogenetic proximity found between Neotropical and Australian groups reveal an interesting biogeographic scenario to be investigated. After examining 33 out of the 36 type specimens designated for the species and subspecies of Heteroponerinae, six species are recognized in the genus Acanthoponera, two of which are here described as new. Heteroponera comprises 21 species, of which six are described as new; seven are restricted to the Australian Region (three newly described) and 14 are exclusively Neotropical (also three newly described). Heteroponera flava Kempf is synonymized under H. panamensis (Forel) and H. georgesi Perrault becomes a junior synonym of H. microps Borgmeier. Individuals yet not registered of castes and sexes (including males, gynes and workers) are here described for the first time for different species of Heteroponerinae. New records greatly expand the known distribution for most species. Field observations allied to label data from museum specimens provide important additional information about the natural history of the group. Larvae of Heteroponerinae are predominantly predators, and workers are occasionally observed feeding on plant exudates. Nests can support colonies with a some dozens to a few hundred of individuals. Heteroponera can nest in soil and vegetation, but preferably forage in the soil, while Acanthoponera is exclusively arboreal. With respect to the reproductive strategy, some species of Heteroponera may present ergatoid gynes sharing the reproductive function with dealate gynes, while in other species the winged gynes were completely replaced by ergatoids. As a next step to understand the evolutionary history of this group it is suggested an analysis of the internal relations within the heteroponerine genera using molecular tools and a study on the subfamily biogeographic patterns.

Plantago ovata Forssk. (Plantaginaceae) is a winter annual species which, in North America, inhabits desert and Mediterranean habitats of the southwest United States, northwest Mexico and the Channel Islands of California and Mexico. In the eastern hemisphere P. ovata inhabits desert regions ranging from the Canary Islands, across northern Africa to western India. The wide disjunction between P. ovata in the western and eastern hemispheres poses an interesting question as to the origin and biogeography of the species. Previous authors have hypothesized that P. ovata was introduced to North America over the Bering land bridge, from Asia, during the Miocene, or introduced anthropogenically from Europe during the 18th century by Spanish settlers. In this study we examined sequence data from the chloroplast trnL-trnF, trnS-trnG and psbA-trnH regions, the nuclear ribosomal internal transcribed spacer (ITS) and a region 5' of the TCP region of a CYCLOIDEA gene. Using a molecular clock based on an ITS calibration within the Plantago genus, and a clock for plant chloroplast, we date a non-anthropogenic introduction event, from the Old World to North America, approximately 200,000-650,000 years ago. This is consistent with a Pleistocene origin, and does not support a Miocene origin of the disjunction. Based on a morphological survey of 552 specimens, from throughout the world range of P. ovata, we suggest the recognition of four subspecific taxa. Molecular phylogenetic analysis of chloroplast DNA and nuclear ribosomal DNA ITS sequences support this taxonomic treatment. Furthermore, phylogenetic sequences of the CYCLOIDEA gene support the morphological data. Both suggest the origin of North American P. ovata as a result of hybridization between Old World P. ovata varieties. This event provides further evidence that hybridization may serve as a predictor of invasiveness in plants. / Graduation date: 2005

Stable carbon isotope ratios (δ13C) in tree-ring cellulose are modified by environmental conditions occurring during carbon fixation. Researchers have however not reached a consensus as to whether extractives, lignin and/or hemicelluloses, all with specific isotopic signatures, should be removed prior to dendroisotopic analysis. The topic of the first paper dealt with the comparison of Thuja occidentalis L. wood components and their suitability for subsequent dendroisotopic analyses. It was recommended that holocellulose be isolated since an alpha-cellulose yield may be too low for subsequent mass spectrometer analysis, especially when narrow rings are encountered and multiple stable isotope analyses are to be performed per sample. The second paper investigated the associations between the ring-width and δ13C chronologies with climate variables. The δ13C chronology spanned from 1650 to 2006 A.D. and incorporated dead and living T. occidentalis trees selected from two sites in central Manitoba, Canada. Compared to the δ13C values, ring width was more often associated with climate conditions in the year prior to ring formation. However, moisture stress was limiting for both radial growth and carbon assimilation. During the year of ring-formation, ring width was associated with spring and early summer conditions whereas, δ13C was more indicative of overall summer conditions. Nonetheless, each of ring width and δ13C contained individualistic climate information which could be used in tandem for long-term climate reconstruction.

Stable carbon isotope ratios (δ13C) in tree-ring cellulose are modified by environmental conditions occurring during carbon fixation. Researchers have however not reached a consensus as to whether extractives, lignin and/or hemicelluloses, all with specific isotopic signatures, should be removed prior to dendroisotopic analysis. The topic of the first paper dealt with the comparison of Thuja occidentalis L. wood components and their suitability for subsequent dendroisotopic analyses. It was recommended that holocellulose be isolated since an alpha-cellulose yield may be too low for subsequent mass spectrometer analysis, especially when narrow rings are encountered and multiple stable isotope analyses are to be performed per sample. The second paper investigated the associations between the ring-width and δ13C chronologies with climate variables. The δ13C chronology spanned from 1650 to 2006 A.D. and incorporated dead and living T. occidentalis trees selected from two sites in central Manitoba, Canada. Compared to the δ13C values, ring width was more often associated with climate conditions in the year prior to ring formation. However, moisture stress was limiting for both radial growth and carbon assimilation. During the year of ring-formation, ring width was associated with spring and early summer conditions whereas, δ13C was more indicative of overall summer conditions. Nonetheless, each of ring width and δ13C contained individualistic climate information which could be used in tandem for long-term climate reconstruction.

Heteroponerinae Bolton (2003) compreende três gêneros de formigas: Acanthoponera Mayr, Aulacopone Arnol\'di e Heteroponera Mayr. Acanthoponera é exclusivamente Neotropical, enquanto Heteroponera mostra uma distribuição disjunta nas Américas e Oceania. O gênero Aulacopone, de posição incerta na subfamília, é conhecido por uma única espécie representada por um par de rainhas coletadas por volta da década de 1930 em duas localidades no sudoeste da Ásia (Azerbaijão). O presente estudo representa a primeira revisão taxonômica global de Heteroponerinae em nível específico e a primeira tentativa de se analisar as relações filogenéticas internas da subfamília com base em caracteres morfológicos externos de todos os táxons nela incluídos. O estudo dos terminais utilizados na análise filogenética resultou em uma matriz com 101 caracteres, sendo 50 destes empregados pela primeira vez em uma análise cladística envolvendo formigas. A análise filogenética demonstra a monofilia de Heteroponerinae, com pelo menos quatro sinapomorfias sustentando esta hipótese. Os gêneros Acanthoponera e Heteroponera também são monofiléticos em todas as topologias aqui encontradas. As relações internas apontam para uma posição basal do gênero paleártico Aulacopone, que figura como grupo-irmão do clado Acanthoponera + Heteroponera. Ainda assim, devido à falta de caracteres que ofereçam maior suporte à inclusão de Aulacopone em Heteroponerinae, este gênero é mantido como incertae sedis na subfamília. A relativa falta de resolução nas relações internas em Acanthoponera e nos ramos mais apicais de Heteroponera não impede o reconhecimento de algumas linhagens como evolutivamente independentes. A presença destas linhagens em pelo menos duas regiões biogeográficas e a proximidade filogenética encontrada entre grupos neotropicais e australianos revelam um interessante cenário biogeográfico a ser investigado. Após o exame de 33 dos 36 espécimes-tipo designados para as espécies e subespécies de Heteroponerinae, seis espécies são reconhecidas para o gênero Acanthoponera, das quais duas são descritas como novas. Heteroponera apresenta 21 espécies (seis delas descritas aqui pela primeira vez), sete das quais restritas à Região Australiana (três novas) e 14 exclusivamente neotropicais (três novas). Heteroponera flava Kempf é sinonimizada sob H. panamensis (Forel) e H. georgesi Perrault passa a ser sinônimo júnior de H. microps Borgmeier. Indivíduos de castas e sexos ainda não registrados (incluindo machos, gines e operárias) são aqui descritos pela primeira vez para diferentes espécies de Heteroponerinae. Novos registros de localidades expandem significativamente a distribuição conhecida para a maior parte das espécies. Observações de campo aliadas a dados de rótulo de espécimes de museus fornecem importantes informações adicionais acerca da história natural do grupo. Larvas de Heteroponerinae são predominantemente predadoras, alimentando-se de pequenos artrópodes coletados pelas operárias. Ocasionalmente, adultos podem se alimentar dos líquidos (hemolinfa) resultantes das feridas provocadas no tegumento das presas caçadas por operárias e de exudatos vegetais no caso de espécies arborícolas. Os ninhos de Heteroponera são encontrados no solo ou na vegetação e podem abrigar colônias com algumas dezenas a poucas centenas de indivíduos, sendo que as operárias forrageiam preferencialmente no solo. Acanthoponera nidifica e forrageia exclusivamente em árvores. Com relação à estratégia reprodutiva, algumas espécies de Heteroponera podem apresentar gines ergatóides dividindo a função reprodutiva com as gines aladas na mesma colônia, enquanto em outras espécies as gines aladas foram completamente substituídas por ergatóides. Como uma próxima etapa para a compreensão da história evolutiva deste grupo sugere-se uma análise das relações internas dos gêneros através de ferramentas moleculares e um estudo dos padrões biogeográficos de Heteroponerinae. / Heteroponerinae Bolton (2003) comprises three ant genera: Acanthoponera Mayr, Aulacopone Arnol\'di and Heteroponera Mayr. Acanthoponera is exclusively Neotropical, while Heteroponera shows a disjunct distribution in the Americas and Australia. The position of Aulacopone within the subfamily is uncertain as it is known by a single species represented by two gynes collected around the 1930s in two localities in Southeast Asia (Azerbaijan). This study represents the first comprehensive taxonomic revision of Heteroponerinae at specific level and the first attempt to analyze the internal phylogenetic relationships of the subfamily based on the external morphology of all heteroponerine taxa. The study of the species used in the phylogenetic analysis resulted in a matrix with 101 characters, of which 50 are used for the first time in a cladistic analysis involving ants. The phylogenetic analysis demonstrates the monophyly of Heteroponerinae with at least four synapomorphies supporting this hypothesis. The genera Acanthoponera and Heteroponera are also monophyletic in all topologies found here. The internal relationships indicate a basal position of the paleartic genus Aulacopone, which appears as sister group to the clade Acanthoponera + Heteroponera. Due to the lack of characters to provide robust support to the inclusion of Aulacopone within Heteroponerinae, this genus is considered as incertae sedis in the subfamily. The relative low resolution of the internal relationships in Acanthoponera and in the apical branches of Heteroponera does not prevent the recognition of evolutionarily independent lineages. The presence of these lineages in at least two biogeographic regions and the phylogenetic proximity found between Neotropical and Australian groups reveal an interesting biogeographic scenario to be investigated. After examining 33 out of the 36 type specimens designated for the species and subspecies of Heteroponerinae, six species are recognized in the genus Acanthoponera, two of which are here described as new. Heteroponera comprises 21 species, of which six are described as new; seven are restricted to the Australian Region (three newly described) and 14 are exclusively Neotropical (also three newly described). Heteroponera flava Kempf is synonymized under H. panamensis (Forel) and H. georgesi Perrault becomes a junior synonym of H. microps Borgmeier. Individuals yet not registered of castes and sexes (including males, gynes and workers) are here described for the first time for different species of Heteroponerinae. New records greatly expand the known distribution for most species. Field observations allied to label data from museum specimens provide important additional information about the natural history of the group. Larvae of Heteroponerinae are predominantly predators, and workers are occasionally observed feeding on plant exudates. Nests can support colonies with a some dozens to a few hundred of individuals. Heteroponera can nest in soil and vegetation, but preferably forage in the soil, while Acanthoponera is exclusively arboreal. With respect to the reproductive strategy, some species of Heteroponera may present ergatoid gynes sharing the reproductive function with dealate gynes, while in other species the winged gynes were completely replaced by ergatoids. As a next step to understand the evolutionary history of this group it is suggested an analysis of the internal relations within the heteroponerine genera using molecular tools and a study on the subfamily biogeographic patterns.

Les Composés Organiques Volatils (COV) jouent un rôle important dans la chimie de l'atmosphère et participent à la formation de polluants secondaires comme l'ozone et les aérosols organiques. Les émissions biogéniques de COV dominent d'un facteur dix les émissions anthropiques à l'échelle globale mais leur caractérisation à l'échelle régionale est incertaine. Les progrès en modélisation de la chimie atmosphérique passent par l'amélioration des inventaires d'émissions, ce qui nécessite des mesures de flux in situ. Ces travaux portent sur l'étude des émissions de COV biogéniques par les végétations méditerranéennes dans le cadre du programme ChArMEx (Chemistry and Aerosol Mediterranean Experiment) qui vise à concentrer les efforts scientifiques sur l'étude de la chimie et des aérosols de l'atmosphère du bassin méditerranéen. La méthode Eddy Covariance (EC) permet de quantifier directement les échanges d'espèces chimiques entre la surface et l'atmosphère. Cette méthode constitue une référence pour les mesures de flux mais n'est applicable qu'à un nombre limité d'espèces car elle requiert la mesure rapide (~ 0,1 s) et simultanée de la concentration du composé étudié ainsi que de la vitesse du vent vertical. Afin d'élargir le champ de mise en œuvre de cette technique d'autres solutions dérivées de l'EC ont été proposées, dont la méthode Disjunct Eddy Covariance (DEC) qui a pour particularité de réduire la contrainte sur la mesure rapide de l'espèce chimique tout en gardant une précision acceptable sur le calcul du flux. Dans le cadre de ces travaux de thèse un système de prélèvement a été développé pour mettre en œuvre la mesure de flux de COV par la méthode DEC. Ce dispositif appelé MEDEE (Mesures par Échantillonnage Disjoint des Échanges d'Espèces en trace) repose sur une technologie nouvelle qui permet une capture rapide d'un échantillon d'air et assure son transfert à pression constante vers un analyseur connecté en ligne. Il est composé de deux "seringues mécaniques" actionnées par des vérins électriques dont le fonctionnement est alterné pour alimenter en continu l'analyseur. Trois électrovannes disposées à l'entrée de chaque réservoir dirigent le flux d'air en fonction du cycle de fonctionnement. L'ensemble du système est cadencé par un microcontrôleur avec une précision à la milliseconde. Le système de prélèvement a été réalisé en matériaux inertes chimiquement pour éviter la dégradation de l'échantillon et être compatible avec les espèces en trace réactives. MEDEE a été testé et validé pour les mesures de flux au sol et en avion lors de deux campagnes de terrain. Le système MEDEE a ainsi permis, lors de deux campagnes de mesures pendant les étés 2010 et 2011 au-dessus d'une forêt de chênes pubescents, de mesurer les flux d'isoprène grâce à un couplage avec un analyseur adapté (Fast Isoprene Sensor). Un réseau de neurones artificiels (RNA) a ensuite été utilisé pour déterminer une paramétrisation des flux d'isoprène en fonction des paramètres environnementaux à partir des observations des campagnes de mesures. La modélisation des émissions d'isoprène a été validée pour les conditions environnementales rencontrées. Cette paramétrisation servira dans un modèle de chimie atmosphérique à l'étude de l'impact des émissions de COV biogéniques sur la qualité de l'air.

Adverbial constructions are a problematic subject in Tswana grammatical studies. Traditionally termed descriptives, it is not clear what the defining features of this category are. It is also a very vast category. There seems to be many different structures functioning as adverbials in Tswana, including particles, words, prepositional phrases and clauses. Tswana grammars in general often have little to say about the syntax of adverbials, in respect of, for instance, the propensity of Tswana adverbials for multiple occurrences in the same clause and the range of possible positions of Tswana adverbials in clause structure. Because of the vastness of the adverbial category we only deal with adverbials as elements of clause structure. A typical feature of adverbials is the considerable mobility they enjoy in relation to other elements in clause structure which affects their grammatical and semantic status in relation to such elements. By distinguishing different categories of adverbials, in clause structure it becomes clear that the same structural element may function within different adverbial categories. This necessitates a definition of adverbials which is based on their specific semantic functions within clause structure. The study is divided into five chapters. When dealing with the adverbial as a clause element in Tswana, we realise that it is not sufficiently described. The first two chapters therefore serve as an introduction to central theoretical issues where some relevant research is critically examined and related to the present study. In the next chapter, that is Chapter 3, we establish formal and semantic frameworks for the classification and descriptive treatment of adverbials in Tswana. In Chapter 4 we implement the structural, syntactic and semantic properties as well as the features adverbials have as modifiers to make a functional classification of adverbials in clause structure. The classification of adverbials as adjuncts, subjuncts, disjuncts and conjuncts from A Comprehensive grammar of the English language by Quirk, et al. (1985) (CGEL) is taken as the basis for this classification. Chapter 5 presents the overall conclusions and implications of the study. / African Languages / D.litt. et Phil. (African Languages)

Adverbial constructions are a problematic subject in Tswana grammatical studies. Traditionally termed descriptives, it is not clear what the defining features of this category are. It is also a very vast category. There seems to be many different structures functioning as adverbials in Tswana, including particles, words, prepositional phrases and clauses. Tswana grammars in general often have little to say about the syntax of adverbials, in respect of, for instance, the propensity of Tswana adverbials for multiple occurrences in the same clause and the range of possible positions of Tswana adverbials in clause structure. Because of the vastness of the adverbial category we only deal with adverbials as elements of clause structure. A typical feature of adverbials is the considerable mobility they enjoy in relation to other elements in clause structure which affects their grammatical and semantic status in relation to such elements. By distinguishing different categories of adverbials, in clause structure it becomes clear that the same structural element may function within different adverbial categories. This necessitates a definition of adverbials which is based on their specific semantic functions within clause structure. The study is divided into five chapters. When dealing with the adverbial as a clause element in Tswana, we realise that it is not sufficiently described. The first two chapters therefore serve as an introduction to central theoretical issues where some relevant research is critically examined and related to the present study. In the next chapter, that is Chapter 3, we establish formal and semantic frameworks for the classification and descriptive treatment of adverbials in Tswana. In Chapter 4 we implement the structural, syntactic and semantic properties as well as the features adverbials have as modifiers to make a functional classification of adverbials in clause structure. The classification of adverbials as adjuncts, subjuncts, disjuncts and conjuncts from A Comprehensive grammar of the English language by Quirk, et al. (1985) (CGEL) is taken as the basis for this classification. Chapter 5 presents the overall conclusions and implications of the study. / African Languages / D.litt. et Phil. (African Languages)

Orientador: Anna Diva Plasencia Lotufo / Resumo: A lógica de múltiplos valores, em especial a ternária, apresenta inúmeras vantagens sobre a lógica binária em circuitos reversíveis/quânticos. A realização de funções usando a lógica reversível ternária é conhecida por requerer um menor número de linhas em comparação com a lógica reversível binária convencional. Este aspecto tem motivado as pesquisas em abordagens de síntese. A grande maioria dos métodos existentes requerem entradas adicionais, denominadas de ancillary lines, durante o processo de síntese, o que é dispendioso para implementação em tecnologias quânticas, quando disponíveis. Neste trabalho, foram propostas diferentes metodologias e análises comparativas para o problema da síntese de circuitos reversíveis ternários sem a adição de ancillary lines. A metodologia de síntese proposta, denominada de MMD plus, foi aplicado nos modos backward e top-down como referência a todas as 362880 possíveis funções reversíveis ternárias de 2 variáveis. Além do processamento top-down originário do algoritmo MMD, um processamento bottom-up é implementado e sua eficiência comparativa é avaliada. Por definição, as funções reversíveis ternárias são permutações. Realiza-se a decomposição das permutações em ciclos disjuntos de ordem natural, em ciclos de permutação com 3 elementos, e em transposições, para obtenção dos circuitos reversíveis ternários. Uma métrica é introduzida para mensurar a complexidade e custo dos circuitos, com base nas portas reversíveis de múltiplos valores Muthu... (Resumo completo, clicar acesso eletrônico abaixo) / Doutor