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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.
331

Comportamento territorial de Hylodes nasus em um riacho na Floresta da Tijuca, Rio de Janeiro. / Territorial behavior of Hylodes nasus in a stream at Floresta da Tijuca, Rio de Janeiro

Vinicius Carvalho da Silva e Souza 28 February 2011 (has links)
O comportamento territorial é exibido por animais que competem por recursos dentro de uma área específica defendida. Ao excluir competidores potenciais desta área através de comportamentos agressivos, os indivíduos territoriais garantem acesso prioritário aos recursos essenciais para sua sobrevivência e reprodução. Em anfíbios anuros, a territorialidade tem sido relacionada principalmente com espécies de reprodução prolongada, cujos sítios reprodutivos estão disponíveis durante todo o ano. O presente trabalho foi realizado em um trecho de riacho na Floresta da Tijuca, Rio de Janeiro. Foram realizadas quatro visitas consecutivas a área de amostragem em cada mês (abril/2009 à agosto/2010). O objetivo foi responder questões sobre a territorialidade dos indivíduos da espécie Hylodes nasus: (área de vida, fidelidade ao sítio, comportamentos agonísticos e combates físicos). As áreas de vida dos machos apresentaram relação significativa com o número de recapturas. O tamanho da área de vida das fêmeas foi ligeiramente maior do que dos machos. Os machos apresentaram maior fidelidade do que as fêmeas. A fidelidade apresentou resultado significativo com o CRC e a massa corporal dos indivíduos. Foram observadas 50 interações agonísticas entre machos, sendo exibidos 11 comportamentos agressivos. Foram observados 19 combates físicos, sendo os machos envolvidos classificados como residente, intruso, vencedor ou perdedor. Todas as disputas foram vencidas por indivíduos residentes. Informações a respeito da influência de fatores ambientais sobre a população de H. nasus, aspectos da estrutura populacional e descrição do microhábitat também são fornecidos. / The territorial behavior is exhibited by animals that compete for resources within a specific defended area. By excluding potential competitors in this area through aggressive behavior, territorialist individuals ensure priority access to essential resources for their survival and reproduction. In anuran amphibians, territoriality has been mainly related to prolonged-breeding species, whose breeding sites are available throughout the year. This study was conducted in a portion of the river in the Tijuca Forest, Rio de Janeiro. There were four consecutive visits to the sampling area in each month (April/2009 to August/2010). The objective was to answer questions about the territorial behavior of Hylodes nasus (home range, site fidelity, agonistic behaviors and physical fighting). The males home range showed a significant relation with number of recapture. The home range estimated for females was slightly larger than males. Males have higher site fidelity than females. The site fidelity showed a significant relation with individuals' SVL and body mass. There were observed 50 agonistic encounters between males, showing 11 aggressive behaviors. There were observed 19 physical fights with males being classified as resident, intruder, winner or loser. All contests were won by resident individuals. Information about the influence of environmental factors on the population of H. nasus, aspects of population structure and description of microhabitat are also provided.
332

Moldagem por injeção de microcomponentes ópticos poliméricos gerados em insertos usinados por torneamento de ultraprecisão / Injection molding of polymer micro-optical components generated in inserts by ultra-precision turning

Renê Mendes Granado 17 December 2010 (has links)
Este trabalho analisou o processo de moldagem por injeção de micro elementos ópticos difrativos usinados em insertos de cobre eletrolítico com ferramenta de diamante com ponta única. Quatro tipos de microestruturas características foram selecionados neste estudo, a saber: lente anesférica, lente de Fresnel, grade de difração (blaze grating) e sensor de frente de onda. A análise da fidelidade de replicação foi feita considerando aspectos dimensionais micrométricos e nanométricos para a microestrutura e acabamento. Um perfilometro óptico e microscópio eletrônico de varredura foram utilizados para avaliar os insertos usinados e as características dos replicados. Uma ferramenta de diamante com geometria especial, com meio raio, foi usada para usinar as características de difração. As superfícies usinadas apresentaram baixo acabamento superficial, na faixa de 16 nm Rms. As simulações numéricas foram realizadas para avaliar o desempenho do processo de moldagem por injeção com polimetilmetacrilato (PMMA), e os resultados foram utilizados para orientar a injeção do polímero. Com base na simulações numéricas as temperaturas do molde e pressões de injeção foram variadas entre 85ºC/130°C e 70 bar/130 bar, respectivamente. A influência destes parâmetros no desempenho do processo de replicação foi analisada. A análise quantitativa da replicação foi feita através de um parâmetro denominado grau de replicação que define a relação entre a altura nominal da microestrutura do inserto e à altura da microestrutura na réplica de polímero. A grade de difração e o sensor de frente de onda apresentaram os melhores níveis de replicação: 98% e 99%, respectivamente. Os resultados experimentais mostraram que o processo de moldagem por injeção é uma técnica viável para replicar com alta qualidade microcaracterísticas de elementos ópticos de difração gerados por torneamento com ferramenta de diamante com ponta única. / This work investigated the injection molding process of micro diffractive optical elements machined on electrolytic copper inserts by single point diamond turning. Four types of microstructure features were selected in this study, namely: aspherical lens, Fresnel lens, blaze grating and the wavefront sensor. The replication fidelity was evaluated in terms of dimensional micrometric features found in the microstructure and the surface finish. An optical profiler and scanning electron microscopy were used to assess the machined inserts and the replicated features. A special geometry diamond tool with half radius was used to machine the diffraction features. The machined surfaces presented very low surface finish in the range of 16 nm Rms. Numerical simulations were carried out to evaluate the performance of the injection molding process with polymethylmethacrylate (PMMA), and the results were used to guide the polymer injection. Based on numerical simulations mold temperatures and injection pressures were varied between 85°C/130°C and 70 bar/130 bar, respectively. The influence of these parameters on performance of the replication process was assessed. The quantitative assessement of the replication was made by using a parameter called degree of replication which defines the ratio between the nominal height of the microstructure in the insert and the height of the microstructure in the polymer replica. The blaze grating and the wavefront sensor presented the best degrees of replication: 98% and 99%, respectively. The experimental results showed that injection molding process is a viable technique to replicate high quality micro features of optical diffraction elements generated by single point diamond turning.
333

Fidélité de la traduction chez les eucaryotes. De la molécule au génome / Translational fidelity in eukaryotes. From the molecule to the genome

Chommy, Hélène 21 September 2012 (has links)
Ce travail porte sur l’étude de la fidélité de la traduction chez les eucaryotes d’un point de vue mécanistique et génomique. Au cours de ma thèse j'ai développé trois approches :Le premier projet porte sur l’étude du rôle du facteur de l’élongation eEF2 dans le maintien du cadre de lecture. La stratégie associe une mutagénèse aléatoire du gène EFT2 à un criblage phénotypique, elle permet d’isoler des mutants capables d’augmenter ou diminuer l’efficacité de recodage d’une séquence de décalage du cadre de lecture en -1.Le second projet décrit la mise au point d’un système de traduction en molécule unique qui permet d’étudier le ribosome eucaryote. La traduction est initiée grâce à l’IRES CrPV qui a pour caractéristique d’être totalement indépendante des facteurs d’initiation et de l’ARNt initiateur. L’élongation de la traduction est détectée grâce au départ d’un oligonucléotide fluorescent qui est décroché par l’activité hélicase du ribosome. Les résultats de ces expériences constituent une preuve de principe démontrant que l’étude de la traduction eucaryote en molécule unique est possible.Le troisième projet est une étude de génomique comparative qui permet de rechercher des événements de recodage ainsi que d’autres événements non-conventionnels de la traduction dans le génome de la levure Saccharomyces cerevisiae. L’approche est basée sur une recherche d’organisations génomiques conservées au sein de 19 génomes de levures. Les gènes candidats sont testés in vivo grâce à un vecteur double rapporteur. Cette étude a permis de mettre en évidence le gène VOA1 qui a été ensuite caractérisé plus en détails. / This report describes a study of translation fidelity in Eukarya. Two aspects are tested: the molecular mechanism of recoding and the research of recoding events at the genomic level. During my PhD I have developed three projects:The first project deals with the role of the elongation factor eEF2 in reading frame maintenance. The strategy is based on a random mutagenesis of EFT2 and a phenotypic screening in order to isolate mutants increasing or reducing -1 frameshifting efficiency.The second project describes the development of a single molecule translational system to study the eukaryotic ribosome. Translation initiation is mediated by the CrPV IRES which is initiation factor and initiation tRNA independent. Elongation is monitored with the dissociation of a fluorescent oligonucleotide by the helicase activity of the ribosome. This work is a proof of principle that studying eukaryotic ribosome with single molecule techniques is now feasible.The third project is a comparative genomic approach to search for recoding and unconventional translational events in the genome of yeast Saccharomyces cerevisiae. The approach is based on the detection of conserved genomic organization among 19 Fungi genomes. The candidate genes are then tested in vivo with a dual reporter system. This study allowed the characterization of VOA1 which was further analysed.
334

Enhancing Treatment Fidelity within Underserved Classroom Settings Serving Children with Autism and Developmental Disabilities

Wheeler, John J., Mayton, Michael R., Zhang, Jie 18 January 2012 (has links)
No description available.
335

Multi-Fidelity Model Predictive Control of Upstream Energy Production Processes

Eaton, Ammon Nephi 01 June 2017 (has links)
Increasing worldwide demand for petroleum motivates greater efficiency, safety, and environmental responsibility in upstream oil and gas processes. The objective of this research is to improve these areas with advanced control methods. This work develops the integration of optimal control methods including model predictive control, moving horizon estimation, high fidelity simulators, and switched control techniques applied to subsea riser slugging and managed pressure drilling. A subsea riser slugging model predictive controller eliminates persistent offset and decreases settling time by 5% compared to a traditional PID controller. A sensitivity analysis shows the effect of riser base pressure sensor location on controller response. A review of current crude oil pipeline wax deposition prevention, monitoring, and remediation techniques is given. Also, industrially relevant control model parameter estimation techniques are reviewed and heuristics are developed for gain and time constant estimates for single input/single output systems. The analysis indicates that overestimated controller gain and underestimated controller time constant leads to better controller performance under model parameter uncertainty. An online method for giving statistical significance to control model parameter estimates is presented. Additionally, basic and advanced switched model predictive control schemes are presented. Both algorithms use control models of varying fidelity: a high fidelity process model, a reduced order nonlinear model, and a linear empirical model. The basic switched structure introduces a method for bumpless switching between control models in a predetermined switching order. The advanced switched controller builds on the basic controller; however, instead of a predetermined switching sequence, the advanced algorithm uses the linear empirical controller when possible. When controller performance becomes unacceptable, the algorithm implements the low order model to control the process while the high fidelity model generates simulated data which is used to estimate the empirical model parameters. Once this online model identification process is complete, the controller reinstates the empirical model to control the process. This control framework allows the more accurate, yet computationally expensive, predictive capabilities of the high fidelity simulator to be incorporated into the locally accurate linear empirical model while still maintaining convergence guarantees.
336

Site Fidelity, Associations and Long-Term Bonds of Short-Finned Pilot Whales off the Island of Hawai`i

Mahaffy, Sabre D. 01 January 2012 (has links)
Short-finned pilot whales (Globicephala macrorhynchus) are the most frequently sighted odontocete in a long-term study in Hawaiʹi (representing 23.8% of all odontocete sightings from directed research efforts), yet little has been published on this species in Hawaiian waters. Studies elsewhere have suggested that short-finned pilot whales travel in stable mixed-sex groups composed of strongly associated individuals; however temporal analyses of social structure are lacking. To examine site fidelity, association patterns and temporal relationships, I analyzed data from 267 directed research and opportunistic encounters of short-finned pilot whales off the island of Hawai`i from 2003 through 2007. Sightings occurred year-round. Analysis of sighting depths in relation to effort indicated short-finned pilot whales are strongly associated with the island slope, with no sightings in water >2,700m deep despite effort to ~5,000m. Using only good quality photos, I identified 448 distinctive individuals; of these, 305 (68.1%) were seen more than once and 250 (55.8%) were seen in >1 year. Sighting histories varied from 1-29 sightings per individual (median=3) over the course of the study, suggesting only some individuals exhibit high site-fidelity. Degree of residency was assessed using multi-year site fidelity to the study area; individuals seen ≥5 times in ≥3 years were considered core residents (154 individuals) while individuals who fell below these criteria but that were seen more than once were termed residents (150 individuals) and those seen on a single occasion were termed visitors (142 individuals). Only 71.9% of the whales were linked by association into a single social network, suggesting the possibility of multiple populations using the study area. Individuals demonstrated preferential associations and community division was strongly supported by average-linkage hierarchical cluster analysis of the association data. Nine longitudinally-stable social units composed of key individuals (seen together ≥8 times in ≥4 years) and their constant companions (seen together ≥5 times in ≥3 years) were identified (unit membership 5-16, median=10.5; mean unit association index: 0.62-0.90). Qualitative assignment of age and sex classes to unit members indicated some segregation between adult males and female/calf pairs may occur. Temporal analysis using standardized lagged association rates of individuals grouped in the same encounter produced a best-fit model where dyads gradually disassociated over time while individuals grouped in the same day produced a model where dyads remained in association, suggesting companions not documented during an encounter are likely still present in the study area. Differential patterns of residency and site fidelity were unexpected and may be indicative of multiple populations around the main Hawaiian Islands. Additionally, the presence of a core resident population demonstrating strong, long-term site-fidelity and associations off the island of Hawaiʹi may warrant special management considerations. Evidence of fisheries-related injuries in addition to anthropogenic threats such as high levels of commercial and recreational vessel traffic, targeted tourist activities, and commercial and sports troll fisheries indicate that additional research is needed to evaluate potential threats to this island-associated population.
337

Response to Intervention Teachers' Perspective of Tier 2 Intervention Fidelity

Meissner, Doretha 01 January 2016 (has links)
In an urban Texas school district, teachers and administrators were concerned about students' achievement and the teachers' knowledge and implementation of Response to Intervention (RTI) Tier 2 interventions with fidelity. This study addressed teachers' perceptions of the reliability of the application of Tier 2 interventions at the study site, its influence on student achievement, and the appropriateness of current professional development at the targeted campus. The constructivist concept of how people learn and the implementation theory of scaffolding instruction, meaningful experiences, and active learning provided the framework for this study. The educators provided perspectives of how the quality and frequency of the implementation impact the fidelity of Tier 2 interventions. A total of 15 teachers from Grades 3, 4, and 5, the RTI Coordinator, and administrators at the target campus who each met the criteria of more than 2 years of experience working with the RTI process, RTI training, and progress monitoring were included as participants. Data were gathered from the RTI School Readiness Survey, individual interviews, State of Texas Assessment of Academic Readiness for math and reading, and the state required campus and district improvement plans. The data were examined using comparative analyses, inductive generalizations, and analytical coding. The results indicated a need for sustained training to improve teacher knowledge of RTI implementation strategies and students' academic performance on grade-level content. This study will promote social change by providing teachers and administrators at the study site information on the RTI process and on the intensive professional development training needed to support student academic success.
338

Abundance, behaviour and habitat use patterns of Indo-Pacific bottlenose dolphins (<em>Tursiops aduncus</em>) in the Clarence and Richmond River estuaries in northern New South Wales, Australia

Fury, Christine Ann Unknown Date (has links)
Bottlenose dolphins (Tursiops spp.) are a widely studied species in marine habitats, however, information on estuarine populations in Australia is very limited. To fully understand the importance of estuaries as habitats for dolphins there needs to be clear quantitative data on dolphin populations and their habitat use in estuaries. This study provides the first published data on Indo-Pacific bottlenose dolphins (Tursiops aduncus) abundance estimates, site fidelity, individual ranging patterns, habitat use, flood impacts and sexual segregation patterns over a 3- year period in the Clarence River (CR) and Richmond River (RR) estuaries in northern New South Wales, Australia.The results indicate that, at present, the CR estuary is sustaining a larger dolphin community with a predominantly resident population compared to the RR estuary, which supports a smaller community with lower site fidelity. The CR estuary dolphin abundance estimate of 71 (62-81 95% CI, CV = 0.07) is more than twice the size of the RR estuary abundance estimate of 34 (19- 49 95% CI, CV = 0.23). Differences in site fidelity were observed between the estuaries with 60% and 37% of identified dolphins determined as residents, 26% and 21% as occasional visitors, and 14% and 42% as transients for the CR and RR, respectively. Resource partitioning was apparent in both estuaries with the mean distance resident dolphins were found upstream from the River mouth being greater than for the occasional visitors and transients.Tursiops aduncus was seen all year round in the CR and RR estuaries, with peak sightings occurring in spring at both sites. In the CR the dolphin population showed consistent seasonal fluctuations, whereas this did not occur in the RR population. In the CR the largest spatial distribution of dolphins in the estuary was observed in spring and winter, while in summer they were primarily restricted to the main estuary channel. Different behaviours that were observed; feeding, socialising, travelling, and milling and resting, were found to be influenced by season, tidal phase and tidal range. In both estuaries the core habitat areas used by the population for feeding consisted of areas with considerable slope near the edge of tidal sand banks, adjacent to deeper channels at the entrances of canals, creeks or artificial breakwalls. In addition, the core habitat areas used by the population for milling and resting behaviour in both estuaries occurred in shallow, sheltered areas, often associated with seagrass beds. Socialising occurred more frequently in the CR throughout most of the deeper waters of the estuary, whereas in the RR it was primarily restricted to a small area of medium depth in the estuary.The major determinant of T. aduncus occupancy in the two estuaries was the flood events that occurred, which resulted in the dolphins abandoning the estuary. The mean predicted probabilities for sighting dolphins during non-flood periods were 0.87 and 0.71, during a flood 0.21 and 0.04, and during a post-flood recovery period 0.83 and 0.80 in the CR and RR, respectively. Principal Components Analysis (PCA) showed that when the dolphins were absent from the estuaries, three components were extracted from the water quality parameters in the CR, and two components in the RR. High loadings from the PCA were associated with the changing salinity, turbidity, pH, dissolved oxygen and temperature associated with the flood events. The return of the dolphins to the estuary following a flood depended on the length and severity of the flood event, but generally the dolphins seemed to prefer waters with salinity levels above 29 ‰. This could be associated with higher salinities being important for their physiological health, or because their prey returned to the estuaries during these higher salinity conditions, more likely a combination of both of these factors.Sexual segregation patterns were observed in T. aduncus populations with mixed gender and female groups mainly recorded in the CR, whereas in the RR female groups dominated the estuary. In the CR, significant differences occurred in sightings between the mixed and female groups in relation to water depth and behaviour. Mixed gender groups were sighted predominantly in deeper water and were involved in social behaviour including sexual behaviour and male herding of females. In contrast, the female groups were observed across all water depths, predominately feeding and also participating in more milling and resting behaviours.The high occurrence of aggressive herding behaviour by males in the CR was significantly different at varying depths, tides and seasons, occurring more often in deeper water, at higher tides and in non-breeding seasons. Female groups were found to utilise the small, shallow tributaries and travel for longer distances up these smaller tributaries than the mixed groups, which were concentrated in the deeper main channel of the estuary.The deeper water of the channels may facilitate the males in herding the females, while the female groups’ habitat selection of shallow estuary areas may provide a sanctuary from aggressive males, access to suitable prey items or prey density for mothers and their calves, or a combination of these factors.This study has provided the first detailed research on T. aduncus dolphin population dynamics, habitat use, occupancy and sexual segregation patterns in two Australian subtropical estuaries. To ensure the long-term survival of both of these dolphin populations, management of future increased anthropogenic disturbances from boat traffic, pollution, dolphin watching, industrial or urban development, over-fishing and habitat degradation of the catchment is needed. Good quality water conditions, the protection of the core feeding areas and small shallow tributaries for females and their calves, and sheltered areas for resting behaviour all need to be maintained for the continued conservation of these important dolphin populations.
339

Influences of experience on stories to live by in an elementary classroom

Lawrence, Erin Rae 06 January 2009
This thesis is a narrative inquiry into the experiences of two childrens lives in school. I lived alongside the two children in their grade five classroom for eight months of their school year inquiring into the ways that their school experiences and their relationships with the teacher, classmates, and subject matter influenced the way they composed their stories to live by. In this thesis I share a personal reflection on the way my story to live by has been shaped by my experiences, specifically as a student, a teacher, and a researcher. I use field notes and taped conversations with each of the two boys to retell the stories they shared with me and apply them to literature and theory. I use Deweys Criteria of Experience within a narrative framework to help understand and retell the stories of the two boys as well as Clandinin, Pushor, and Murray Orrs commonplaces of narrative inquiry: place, temporality, and sociality. I explore Aokis planned and lived curriculum and Noddings ethic of care and fidelity in teaching as they applied to the inquiry.
340

Lattice-Based Precoding And Decoding in MIMO Fading Systems

Taherzadeh, Mahmoud January 2008 (has links)
In this thesis, different aspects of lattice-based precoding and decoding for the transmission of digital and analog data over MIMO fading channels are investigated: 1) Lattice-based precoding in MIMO broadcast systems: A new viewpoint for adopting the lattice reduction in communication over MIMO broadcast channels is introduced. Lattice basis reduction helps us to reduce the average transmitted energy by modifying the region which includes the constellation points. The new viewpoint helps us to generalize the idea of lattice-reduction-aided precoding for the case of unequal-rate transmission, and obtain analytic results for the asymptotic behavior of the symbol-error-rate for the lattice-reduction-aided precoding and the perturbation technique. Also, the outage probability for both cases of fixed-rate users and fixed sum-rate is analyzed. It is shown that the lattice-reduction-aided method, using LLL algorithm, achieves the optimum asymptotic slope of symbol-error-rate (called the precoding diversity). 2) Lattice-based decoding in MIMO multiaccess systems and MIMO point-to-point systems: Diversity order and diversity-multiplexing tradeoff are two important measures for the performance of communication systems over MIMO fading channels. For the case of MIMO multiaccess systems (with single-antenna transmitters) or MIMO point-to-point systems with V-BLAST transmission scheme, it is proved that lattice-reduction-aided decoding achieves the maximum receive diversity (which is equal to the number of receive antennas). Also, it is proved that the naive lattice decoding (which discards the out-of-region decoded points) achieves the maximum diversity in V-BLAST systems. On the other hand, the inherent drawbacks of the naive lattice decoding for general MIMO fading systems is investigated. It is shown that using the naive lattice decoding for MIMO systems has considerable deficiencies in terms of the diversity-multiplexing tradeoff. Unlike the case of maximum-likelihood decoding, in this case, even the perfect lattice space-time codes which have the non-vanishing determinant property can not achieve the optimal diversity-multiplexing tradeoff. 3) Lattice-based analog transmission over MIMO fading channels: The problem of finding a delay-limited schemes for sending an analog source over MIMO fading channels is investigated in this part. First, the problem of robust joint source-channel coding over an additive white Gaussian noise channel is investigated. A new scheme is proposed which achieves the optimal slope for the signal-to-distortion-ratio (SDR) curve (unlike the previous known coding schemes). Then, this idea is extended to MIMO channels to construct lattice-based codes for joint source-channel coding over MIMO channels. Also, similar to the diversity-multiplexing tradeoff, the asymptotic performance of MIMO joint source-channel coding schemes is characterized, and a concept called diversity-fidelity tradeoff is introduced in this thesis.

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