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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
371

Improving the Quality of Neural Machine Translation Using Terminology Injection

Dougal, Duane K. 01 December 2018 (has links)
Most organizations use an increasing number of domain- or organization-specific words and phrases. A translation process, whether human or automated, must also be able to accurately and efficiently use these specific multilingual terminology collections. However, comparatively little has been done to explore the use of vetted terminology as an input to machine translation (MT) for improved results. In fact, no single established process currently exists to integrate terminology into MT as a general practice, and especially no established process for neural machine translation (NMT) exists to ensure that the translation of individual terms is consistent with an approved terminology collection. The use of tokenization as a method of injecting terminology and of evaluating terminology injection is the focus of this thesis. I use the attention mechanism prevalent in state-of-the-art NMT systems to produce the desired results. Attention vectors play an important part of this method to correctly identify semantic entities and to align the tokens that represent them. My methods presented in this thesis use these attention vectors to align the source tokens in the sentence to be translated with the target tokens in the final translation output. Then, supplied terminology is injected, where these alignments correctly identify semantic entities. My methods demonstrate significant improvement to the state-of-the-art results for NMT using terminology injection.
372

Forest Change and Balsam Woolly Adelgig Infestation in High Elevation Forests of Mt. Mitchell, North Carolina.

Lusk, Laura 01 December 2009 (has links)
The Black Mountain range of western North Carolina supports some of the most extensive, but threatened high elevation forests in the southern Appalachians. Of particular note, the insect pathogen, balsam woolly adelgid (Adelges piceae Ratzeburg) has been present on Mt. Mitchell for over fifty years. In anticipation of potential changes in forest composition, vegetation surveys were first conducted in 1966 on nine one-acre plots near the summit of Mt. Mitchell. These plots were re-surveyed in 1978, 1985 and 2002. The purpose of this study was to re-census those plots and use those data to analyze long-term trends in forest composition for fir, spruce-fir, and spruce-fir-hardwood forest types. Since the 1960s and 1970s, all three forest types have experienced a transition away from an understory with a preponderance of Fraser fir (Abies fraseri (Pursh) Poir.) seedlings and saplings, to forests with higher densities of canopy and sub-canopy fir. Canopy red spruce (Picea rubens Sarg.) has similarly increased in density in the fir and spruce-fir types but declined in the spruce-fir-hardwood forest type. In all types, there has been a sharp decline in hardwood seedlings/saplings since a hardwood seedling explosion in 1978. The current analyses indicate that fir and spruce-fir forests have regenerated since the most severe die-offs and that each forest type will experience future impacts from balsam woolly adelgid but these will occur in a non-synchronous pattern.
373

Testing the effectiveness of the mt DNA Cytochrome c oxidase subunit 1 (COI) gene locus for identifying species of Polychaete worm (Polychaeta: Annelida) in New Zealand

Brett, Christy Donna January 2006 (has links)
The ability to accurately identify species is fundamental to ecological research and environmental monitoring. Current taxonomic identifications often rely on differentiation of morphologically ambiguous characters, and a process of categorization which is tedious and often leads to misidentifications. This is compounded by the presence of cryptic taxa, which may be prevalent among Polychaete worms (Polychaeta: Annelida). With increased access to genetic techniques, Cytochrome c oxidase subunit I has been suggested as a possible aid to assist in the discrimination of species resources. In this study, I tested the hypothesis that the mtDNA COI gene locus is effective in discriminating morphologically recognised species of Polychaete worms. A 543 base-pair fragment of the COI locus was successfully extracted for 111 individuals from 16 out of 20 morphologically recognised species. Average intraspecific divergences were 0.8 %, ranging from 0 % to 5 %. Average interspecific variation was 26.4 %, ranging from 13.8 % to 36.8 %. The lowest divergences were found between two Nereid species (13.8 %), and two Glycera americana species (17.2 %). Relatively high maximum divergences of over 30 % suggest that some species may have reached a divergence saturation level, which may partially explain why familial groupings in constructed trees were not monophyletic. Divergences within the different Nereid species - a group previously known to have morphologically cryptic species - did not reveal the presence of any cryptic taxa. Pairwise comparisons showed a clear divide between percentages of intra- and interspecific divergences, and the suggested threshold of 11 % is effective for the taxa investigated here. On the basis of these results, I conclude that sequence variation in the mtDNA COI gene locus is effective in discriminating morphologically recognised species of Polychaete worms, but may not be appropriate for deeper (e.g. generic or familial) phylogenetic relationships among taxa.
374

Pastoralism and the transformation of the rangelands of the South Island of New Zealand 1841 to 1912 : Mt Peel Station, a case study

Peden, Robert L, n/a January 2007 (has links)
The transformation of the rangelands of the South Island of New Zealand during the pastoral era fits into the wider international context of European expansion into the 'new' world. European settlers displaced native peoples, introduced 'old' world animals and plants, and imposed a capitalist system that converted local resources into international commodities. In New Zealand the orthodox explanation of the pastoral impact on the rangelands claims that pastoralists introduced an unsustainable system of land use to the region. The pastoralists� indiscriminate burning practices and overstocking with sheep opened up the country to invasion by rabbits. Burning and overgrazing by sheep and rabbits stripped the natural fertility of the soils and left the country depleted, eroded, and overwhelmed by pests and weeds. This thesis sets out to test those claims. It explores burning, the stocking of the rangelands with sheep and the impact of rabbits in detail. It also examines other land management practices, as well as sheep breeding, to see what impact they had on the landscape. The timeframe is set between 1841, when formal British settlement was established in the South Island, and 1912, by which time most of the great estates and stations had been broken up into smaller runs and farms. The thesis uses station diaries, memoirs, contemporary newspapers and farming journals to assess what happened on the ground during the pastoral era. In particular, the thesis uses Mt Peel Station as a case study to examine the intensification in land use that took place between 1841 and 1912, in order to explain the transformation of the landscape and to answer the questions: what happened, how did it happened and why did it happened as it did? These sources illustrate that the pastoral era was characterised by innovation. Pastoralists had access to technical and scientific information from around the world. Some conducted their own experiments to improve the productivity of the land and their stock. There was also a learning process involved in adapting their methods to fit the local rangeland environments. They were not simply rapacious capitalists out to strip the wealth from the land for their own personal gain; indeed, many pastoralists set out to establish viable and sustainable enterprises. The thesis argues that the rangelands consisted of a variety of landscapes and climates. Differences in resource endowments had a considerable influence in shaping the environmental outcomes on different stations. Aridity and rabbits were two key factors in the depletion of the vegetation and the degradation of the landscape in the rangelands. Runs in semi-arid districts that were overwhelmed by rabbits suffered long-term damage. In districts where rainfall was more reliable stations that had been overrun by rabbits recovered remarkably quickly. Stations like Mt Peel, that were largely unaffected by the first rabbit plague, were able to maintain and even increase their productivity up to the time they were subdivided. The orthodox analysis of the transformation of the rangelands in the pastoral era does not account for these differences in outcomes.
375

Étude des modulations à porteuses multiples et à spectre étalé : analyse et optimisation

Baudais, Jean-Yves 04 May 2001 (has links) (PDF)
Les systèmes numériques de communications connaissent un essor considérable sous l'impulsion d'une demande de plus en plus pressante de mobilité, de diversité des services et d'intégration des applications multimédia les plus récentes. Les recherches présentées dans ce mémoire de thèse ont pour but l'étude de nouveaux systèmes de communications qui pourront s'appliquer aussi bien aux systèmes de radiocommunications mobiles qu'aux systèmes de communications à l'intérieur des bâtiments. L'élément nouveau est ici la combinaison de deux techniques : l'étalement de spectre permettant la mise en oeuvre d'un accès multiple à répartition de codes (AMRC) et les modulations à porteuses multiples (OFDM). Cette<br />combinaison permet de tirer partie de la robustesse et de l'efficacité spectrale de l'OFDM, et de la capacité d'accès multiple des techniques AMRC. Deux techniques associant l'OFDM et l'AMRC sont plus particulièrement analysées.<br /><br />La première technique, l'AMRC à porteuses multiples est étudiée sur un canal de Rayleigh à trajets multiples. En réception, plusieurs techniques d'égalisation ou de traitement de diversité sont mises en oeuvre et une approche plus globale de la détection est proposée. Elle consiste à intégrer la fonction de désétalement dans le processus d'égalisation, permettant ainsi d'améliorer la fiabilité de la détection. Ces techniques d'égalisation sont insérées et combinées de différentes façons dans des structures d'annulation d'interférences.<br /><br />Si le système AMRC à porteuses multiples est généralement proposé pour des liaisons synchrones ou quasi-synchrones, le système AMRC<br />multipilote peut être utilisé dans un contexte asynchrone. Les performances théoriques de ce système sont développées et comparées aux performances des systèmes AMRC à porteuse unique.
376

Disentangling Lecania

Reese Næsborg, Rikke January 2007 (has links)
This thesis focuses on phylogenetic, taxonomic, ecological, and conservation aspects of the crustose lichen genus Lecania (Ramalinaceae, lichenized Ascomycota). Lecania has previously been defined on basis of relatively few morphological characters, and the genus had never been treated in molecular phylogenies. The molecular phylogeny of the genus is inferred from DNA sequences. Twenty-five species traditionally placed in Lecania are included in the study along with 21 species from closely related genera. Lecania is a polyphyletic genus. A well-supported monophyletic group containing 16 Lecania species, including the type species L. fuscella is discovered, i.e. Lecania s. str. Nine species formerly included in Lecania do not belong in the genus. A new species, L. belgica, is described. The relationships of a group of morphologically similar Lecania species, i.e. the L. cyrtella group are investigated using morphological and molecular methods. Haplotype network and phylogenetic analyses indicate that the included species, as conceived in the morphological examinations, all are monophyletic. Two new species, L. leprosa and L. madida, are described, L. proteiformis is resurrected from synonymy, and the known range of L. prasinoides is greatly expanded. The type species Lecania fuscella has become endangered in many countries. Twelve localities in Sweden where the species had been found historically are investigated, but L. fuscella is only recovered in one locality. The species composition in these 12 localities, 58 old and 5 new collections with L. fuscella is determined and analyzed. The vegetation community differs between the old and the new collections, and between the locality where the species is recovered and those where it is not. Lecania fuscella has not been able to adapt to environmental changes and now only appears in a specific type of vegetation community. The phylogenetic diversity of the species is calculated, but does not reflect the species’ evolutionary potential.
377

The influence of attention on motion processing

Stephan, Valeska Marija 25 October 2012 (has links)
No description available.
378

Pastoralism and the transformation of the rangelands of the South Island of New Zealand 1841 to 1912 : Mt Peel Station, a case study

Peden, Robert L, n/a January 2007 (has links)
The transformation of the rangelands of the South Island of New Zealand during the pastoral era fits into the wider international context of European expansion into the 'new' world. European settlers displaced native peoples, introduced 'old' world animals and plants, and imposed a capitalist system that converted local resources into international commodities. In New Zealand the orthodox explanation of the pastoral impact on the rangelands claims that pastoralists introduced an unsustainable system of land use to the region. The pastoralists� indiscriminate burning practices and overstocking with sheep opened up the country to invasion by rabbits. Burning and overgrazing by sheep and rabbits stripped the natural fertility of the soils and left the country depleted, eroded, and overwhelmed by pests and weeds. This thesis sets out to test those claims. It explores burning, the stocking of the rangelands with sheep and the impact of rabbits in detail. It also examines other land management practices, as well as sheep breeding, to see what impact they had on the landscape. The timeframe is set between 1841, when formal British settlement was established in the South Island, and 1912, by which time most of the great estates and stations had been broken up into smaller runs and farms. The thesis uses station diaries, memoirs, contemporary newspapers and farming journals to assess what happened on the ground during the pastoral era. In particular, the thesis uses Mt Peel Station as a case study to examine the intensification in land use that took place between 1841 and 1912, in order to explain the transformation of the landscape and to answer the questions: what happened, how did it happened and why did it happened as it did? These sources illustrate that the pastoral era was characterised by innovation. Pastoralists had access to technical and scientific information from around the world. Some conducted their own experiments to improve the productivity of the land and their stock. There was also a learning process involved in adapting their methods to fit the local rangeland environments. They were not simply rapacious capitalists out to strip the wealth from the land for their own personal gain; indeed, many pastoralists set out to establish viable and sustainable enterprises. The thesis argues that the rangelands consisted of a variety of landscapes and climates. Differences in resource endowments had a considerable influence in shaping the environmental outcomes on different stations. Aridity and rabbits were two key factors in the depletion of the vegetation and the degradation of the landscape in the rangelands. Runs in semi-arid districts that were overwhelmed by rabbits suffered long-term damage. In districts where rainfall was more reliable stations that had been overrun by rabbits recovered remarkably quickly. Stations like Mt Peel, that were largely unaffected by the first rabbit plague, were able to maintain and even increase their productivity up to the time they were subdivided. The orthodox analysis of the transformation of the rangelands in the pastoral era does not account for these differences in outcomes.
379

Segregation within afferent pathways in primate vision

Roy, Sujata January 2009 (has links)
The current knowledge of the visual pathways in primates includes the patterns of projection from the retina through the dorsal lateral geniculate nucleus (dLGN) to the striate cortex (V1) and the extra-striate projections towards the dorsal and ventral streams. Cells with short wavelength sensitive cone (S-cone) inputs in the dLGN have been studied extensively in New World marmosets but not in Old World macaques. This thesis presents results from studies in the macaque monkey which are more relevant to humans since humans are closer in evolution to Old World than New World monkeys. / The spatial, temporal, chromatic and orientation preferences of neurons in the dLGN of the macaque were investigated by electrophysiological methods. The physiological findings of cells with S-cone inputs were compared to cells with opponent inputs from the long and medium wavelength sensitive cones (L-cones & M-cones, respectively). The cells receiving S-cone inputs (blue-yellow or B-Y cells) preferred lower spatial frequencies than the cells with opponent L-cone and M-cone inputs (red-green or R-G cells). Orthodromic latencies from optic chiasm stimulation were measured where possible to distinguish differences in conduction velocity between the cell groups. Although the B-Y cells usually had longer latencies than R-G cells, there wasconsiderable overlap between the cell groups. / The recorded cells were localised through histological reconstruction of dLGN sections stained for Nissl substance. The distribution of B-Y cells within the dLGN was compared to the distribution of R-G cells. The majority of B-Y cells were located within the intercalated koniocellular layers as well as the koniocellular bridges (extensions of the koniocellular layers into the adjacent parvocellular layers). The B-Y cells were also largely segregated within the middle dLGN layers (K3, P3, K4 & P4). The R-G cells were mainly concentrated within the parvocellular layers (P3, P4, P5 & P6) and were evenly distributed throughout the middle and outer layers of the dLGN. / The study also included recordings from the extra-striate middle temporal area (MT) to determine whether a fast S-cone input exists from the dLGN to area MT which bypasses V1. The pattern of cone inputs to area MT neurons was investigated before and during inactivation of V1. The inactivation was done through reversible cooling with a Peltier thermocouple device or focal inactivation with y-amino butyric acid (GABA) iontophoresis. Precise inactivation of V1 to the topographically matching visual fields of the recording sites in area MT revealed a preservation of all three coneinputs in many cells. The subcortical sources of these preserved inputs are discussed with their relevance to blindsight, which is the limited retention of visual perception after V1 damage. Analysis of the latencies of area MT cells revealed a rough segregation into latencies faster or slower than 70 ms. Cells both with and without a significant change in response during V1 inactivation were present in each group. The findings reported in this thesis indicate that some of the preserved inputs in area MT during V1 inactivation may be carried by a direct input from the dLGN which bypasses V1.
380

Ciclo ovogenético e estudo morfológico comparativo do sistema reprodutivo de espécies da ordem Polydesmida (Diplopoda)

Pinheiro, Tamaris Gimenez [UNESP] 22 February 2013 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:35:44Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-02-22Bitstream added on 2014-06-13T19:05:58Z : No. of bitstreams: 1 pinheiro_tg_dr_rcla_parcial.pdf: 88748 bytes, checksum: 91cfdd86fa146f6a4d0f6fb9c08b9feb (MD5) Bitstreams deleted on 2015-06-25T13:01:01Z: pinheiro_tg_dr_rcla_parcial.pdf,. Added 1 bitstream(s) on 2015-06-25T13:03:22Z : No. of bitstreams: 1 000713035_20160306.pdf: 78291 bytes, checksum: fec34fc9a16ffd96992e19f4bde0fba2 (MD5) Bitstreams deleted on 2016-03-07T11:06:16Z: 000713035_20160306.pdf,. Added 1 bitstream(s) on 2016-03-07T11:07:07Z : No. of bitstreams: 1 000713035.pdf: 1097521 bytes, checksum: 53a1914b1b9f91f15512a5389e0621f1 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Pouco se sabe sobre a dinâmica reprodutiva dos diplópodos em seu habitat natural. Em áreas inundáveis como o Pantanal matogrossense, estes organismos desenvolvem estratégias de sobrevivência para suportar as alterações cíclicas do regime hídrico. Diante disso, este estudo visou descrever a estrutura ovariana e o ciclo ovogenético de três espécies de diplópodos da ordem Polydesmida: Poratia salvator e Myrmecodesmus hastatus, encontradas em áreas inundáveis e não inundáveis do Pantanal matogrossense, e Telonychopus klossae, que ocorre no município de Cuiabá, Mato Grosso. Além disso, visou fazer um estudo comparativo da morfologia ovariana dessas espécies, a fim de contribuir para discussões sobre a evolução morfológica deste sistema no grupo. Os indivíduos foram coletados trimestralmente, de dezembro de 2009 a janeiro de 2012, por meio de busca ativa. Parte das fêmeas amostradas foi dissecada, fixada, emblocada e processada para estudos histológicos e histoquímicos e outra foi destinada ao estudo ultramorfológico. Poratia salvator e M. hastatus (Pyrgodesmidae) apresentaram ovário como um órgão tubular único. Telonychopus klossae (Chelodesmidae) possui ovário pareado com presença de ovissacos. O ovário não pareado parece ser uma apomorfia, aparentemente, associada ao tamanho diminuto destas espécies e suas curtas histórias de vida; a condição pareada seria simplesiomórfica e mais comum para as famílias de Polydesmida. Os ovócitos apresentam três estágios de desenvolvimento, diferenciados por caracteres como tamanho, aspecto do ovoplasma e deposição do cório. Com relação aos componentes das células germinativas, a deposição de lípidos foi primeiramente observada, seguida pela deposição de proteínas, carboidratos e cálcio. Estes elementos são derivados tanto de... / Little is known about the reproductive dynamics of the diplopods in their natural habitat. In wetlands, these organisms develop survival strategies to withstand the cyclical changes of the water regime. Thus, this study aims to describe the ovarian structure and the oogenetic cycle of three diplopods species in the order Polydesmida: Poratia salvator and Myrmecodesmus hastatus, found in flooded and non-flooded areas of the Pantanal of Mato Grosso, and Telonychopus klossae, that occurs in the Cuiabá city, Mato Grosso. Moreover, it aims to make a comparative study of the ovarian morphology of these species for to contribute with discussions about the morphological evolution of this system in the group. The animals were collected quarterly from December 2009 to January 2012 through active search. Part of the sampled females was processed for histological and histochemical investigation and other part was intended for ultrastructural study. Poratia salvator and M. hastatus (Pyrgodesmidae) had an unpaired ovary that formed a tubular organ containing oocytes. Telonychopus klossae (Chelodesmidae) had a paired ovary with ovisacs. The unpaired ovary appeared to be apomorphic and was associated with the small size of these species and their short life cycle; the paired condition was symplesiomorphic, commonest to Polydesmida families. The oocytes in these species have three stages of development, which were differentiated by size, aspect of ooplasma and deposition of the chorion. With respect to the components of germ cells, the lipid deposition was noted first, followed by the deposition of proteins, carbohydrates and calcium. These elements are derived either from endogenous sources as exogenous. In all Pantanal seasons occurred females of P. salvator e M. hastatus with oocytes in stage III... (Complete abstract click electronic access below)

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