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Reference intervals (RIs) are sets of percentiles that outline the range of laboratory test results belonging to healthy individuals. They are essential for the interpretation of laboratory test results. A wide variety of factors affect the validity of RIs. Among them are the statistical methods used to estimate RIs. However, little investigation has gone into the effect that different statistical methods have on the resulting RIs. This is particularly needed as the complexity of paediatric data makes it difficult to estimate RIs. These difficulties, however, can be addressed using appropriate statistical techniques, provided that there is an outline of scenarios under which these techniques are truly “appropriate”. The objective of this thesis is to provide a thorough investigation into the effect of different statistical methods on RIs. A systematic review was first conducted with a focus on paediatric RIs. The results of this review revealed that critical analysis steps are often overlooked due to complicated paediatric data. Even though a guideline addressing the establishment of RIs is available, there is great heterogeneity in the statistical methods chosen to estimate paediatric RIs. An extensive simulation involving the three most commonly used approaches to estimate RIs (the parametric, non-parametric, and robust methods) was also conducted to investigate and compare the performance of the different methods. The simulation results show that, when data follows a Gaussian distribution, or close to it, the parametric method provides the best estimates. The non-parametric method did not provide the best estimates of RIs (compared to the parametric method) unless data was highly skewed and/or large sample sizes were used. In addition, the bias and MSE associated with the parametric method when data follows a Gaussian distribution was mathematically derived, which may lead to the development of a bias corrected and more precise approach in the future. / Thesis / Master of Science (MSc)

Objectives: Phase 1) Establish echocardiographic reference intervals for measurements of the normal canine right heart. Phase 2) Describe the repeatability of normal right heart echocardiographic measurements. Phase 3) Describe the repeatability of right heart echocardiographic measurements which predict pulmonary artery pressure. Materials and Methods: Phase 1) 45 healthy adult dogs. Dogs underwent one echocardiographic examination by the same operator. Phase 2) 6 randomly selected dogs from the pool of Phase 1 dogs. Dogs underwent repeated echocardiograms by two operators. Phase 3) 4 client-owned dogs. Dogs underwent repeated echocardiographic examination by two operators. Results: Phase 1) The linear relationship between dimension and transformed body weight was highly variable. For linear dimensions, most of the scaling exponents were close to the theoretical value of 1/3. For area measurements, most of the scaling exponents were close to 2/3. Phase 2) Of the 168 within-day, between-day and between-operator coefficients of variation (CV) generated, 154 (91.7%) were below 15% and 135 (80.4%) were less than 10%. Phase 3) Of the 100 within-day, between-day and between-operator CVs generated, 72 (72%) were below 20% and 46 (46%) were below 10%. Conclusions: The right heart can be measured with relatively low repeatability. Measurement of the tricuspid regurgitation velocity should be the first priority when attempting to predict pulmonary artery pressure. If tricuspid regurgitation is not present, the use of transpulmonic acceleration time (AT) and the ratio of transpulmonic acceleration-to-ejection time (AT:ET) to indirectly assess pulmonary artery pressure is recommended. / Master of Science

Formaldehyde, an important feedstock in industrial processes and manufacture, is widely present in numerous consumer products. Emitted by many types of consumer products and indoor materials, indoor air can contain high concentrations of formaldehyde. Exposure to formaldehyde is hazardous to human health. Thus knowledge of formaldehyde mass-transfer properties is critical to efforts to reduce formaldehyde emissions and establish related standards and regulations. The primary objectives of this project include: 1) documenting and validating procedures and methods for analyzing and measuring formaldehyde mass-transfer characteristics; 2) evaluating and comparing formaldehyde mass-transfer properties in different materials using micro-balance sorption/desorption tests; 3) investigating observed formaldehyde mass-transfer irreversibility and the recently developed formaldehyde polymerization theory. The procedures and methods for analyzing and measuring formaldehyde mass-transfer characteristics were developed in an effort to minimize experimental variability and were strictly followed during the research. The formaldehyde mass-transfer properties of five polymer materials (polycarbonate, polystyrene, poly(methyl methacrylate), polyethylene and polypropylene) were measured through sorption/desorption testing. Results indicated that formaldehyde solubility was highest in polyethylene while the rate of diffusion was the highest in polypropylene. Results also showed that the diffusion process in the selected polymer materials was irreversible in all cases. Furthermore, additional testing showed no detectable polyformaldehyde formation on polymer surfaces after exposure to formaldehyde. The causes of observed mass-transfer irreversibility need further study. / Master of Science

The overwhelming trend of the usage of multimedia services has raised the consumers' awareness about quality. Both service providers and consumers are interested in the delivered level of perceptual quality. The perceptual quality of an original video signal can get degraded due to compression and due to its transmission over a lossy network. Video quality assessment (VQA) has to be performed in order to gauge the level of video quality. Generally, it can be performed by following subjective methods, where a panel of humans judges the quality of video, or by using objective methods, where a computational model yields an estimate of the quality. Objective methods and specifically No-Reference (NR) or Reduced-Reference (RR) methods are preferable because they are practical for implementation in real-time scenarios. This doctoral thesis begins with a review of existing approaches proposed in the area of NR image and video quality assessment. In the review, recently proposed methods of visual quality assessment are classified into three categories. This is followed by the chapters related to the description of studies on the development of NR and RR methods as well as on conducting subjective experiments of VQA. In the case of NR methods, the required features are extracted from the coded bitstream of a video, and in the case of RR methods additional pixel-based information is used. Specifically, NR methods are developed with the help of suitable techniques of regression using artificial neural networks and least-squares support vector machines. Subsequently, in a later study, linear regression techniques are used to elaborate the interpretability of NR and RR models with respect to the selection of perceptually significant features. The presented studies on subjective experiments are performed using laboratory based and crowdsourcing platforms. In the laboratory based experiments, the focus has been on using standardized methods in order to generate datasets that can be used to validate objective methods of VQA. The subjective experiments performed through crowdsourcing relate to the investigation of non-standard methods in order to determine perceptual preference of various adaptation scenarios in the context of adaptive streaming of high-definition videos. Lastly, the use of adaptive gain equalizer in the modulation frequency domain for speech enhancement has been examined. To this end, two methods of demodulating speech signals namely spectral center of gravity carrier estimation and convex optimization have been studied.

O objetivo desta dissertação é apresentar uma descrição do processo de referenciação em uma narrativa contada em língua de sinais brasileira (libras), partindo da análise de como o sinalizador introduz e retoma as personagens da narrativa. A descrição é feita com base em trabalhos realizados no âmbito da linguística cognitiva, principalmente na proposta de van Hoek (1997) para a descrição da referenciação, e na proposta de Liddell (2003) para a análise da estrutura dos discursos sinalizados. As línguas sinalizadas, de modo geral e especificamente a libras ainda estão em fase inicial de descrição. A questão da referenciação, que diz respeito ao que está por trás do uso de certas formas de codificação dos referentes em determinados pontos do discurso, já foi amplamente discutida em trabalhos sobre línguas orais. Grande parte das análises, entretanto, tem se baseado na linearidade dessas línguas e, assim, a escolha das formas de codificação é explicada pela distância entre menções do referente. Esse tipo de abordagem, no entanto, não parece ser adequado para a análise de línguas sinalizadas, que são línguas de modalidade visual-gestual. Os discursos, nessas línguas, são organizados espacialmente e a referenciação está fortemente associada à organização do espaço de sinalização pelo sinalizador. O modelo de van Hoek, denominado modelo de pontos de referência, torna-se uma ferramenta interessante para a análise do processo de referenciação em línguas sinalizadas na medida em que se baseia em fatores de natureza cognitiva que não se prendem à linearidade do discurso. A autora propõe que alguns nominais funcionam como pontos de referência conceituais que criam domínios semânticos em que estão inseridos outros nominais. Os fatores que determinam a seleção e a extensão de um ponto de referência são, fundamentalmente, sua proeminência conceitual e sua conectividade conceitual. Para a descrição da estruturação da narrativa, foi utilizado o modelo de Liddell (2003) que, analisando a estrutura do discurso em língua de sinais americana (ASL), chamou a atenção para o papel fundamental que a espacialidade tem nos discursos sinalizados e para a importância de elementos gestuais para a construção dessa espacialidade. A descrição da referenciação neste trabalho é feita a partir de uma narrativa, intitulada O amor é surdo, contada por um surdo adulto fluente em libras. A narrativa foi filmada e transcrita de acordo com o modelo proposto em McCleary, Viotti & Leite (2010), sendo que algumas adaptações e mudanças foram feitas, no decorrer da transcrição, de modo a registrar mais adequadamente todos os detalhes de sinalização. 4 A partir da análise da narrativa, foram levantadas as seguintes formas utilizadas para a referência às personagens: i) sinais; ii) gestos de apontamento; iii) pantomimas e marcas corpóreas, como mudanças na posição do tronco, da cabeça, etc. O nível de elaboração das formas nominais varia de acordo com o grau de proeminência de seu referente. Além disso, foi mostrada a importância da organização espacial para a retomada das personagens ao longo da narrativa, substancialmente estabelecida através da gestualidade no início de cada episódio. / This thesis aims at presenting a description of the reference process in a narrative retold in Brazilian Sign Language (Libras), starting with the analysis of how the signer introduces and refers back to the characters in the narrative studied. This description was based on works developed within the Cognitive Linguistics framework, mainly on van Hoek (1997), used for the description of reference, and Liddell (2003), for the analysis of signed discourses. Signed languages particulary Libras are rather understudied, so they are still in an initial description stage. Reference, which regards the use of certain forms for the coding of referents in specific points in the discourse, has already been widely discussed in works on spoken languages. However, most of these analyses have been based on the linearity of these languages and, as a consequence, they have explained the coding form choice in terms of the distance between the mentioning of a referent. This approach does not seem to be appropriate for signed languages, which, being gestural-visual languages, have their discourse spatially organized and their correference relations strongly associated with a signers organization of the signing space. Van Hoeks model, called the Reference Point Model, has proved to be an interesting tool for the analysis of the reference process in signed language, as it is based in cognitive factors that are independent from the linearity of the discourse. The author proposes that some nominals function as conceptual reference points that create semantic domains in which other nominals are embedded. The factors that determine the selection and extension of a point of reference are, crucially, relative conceptual prominence and connectivity. For the description of the narrative structure, Liddell (2003)s model was used. This model, developed on the basis of the analysis of American Sign Language (ASL), highlights the role of spatiality in signed discourses, as well as the importance of gestural elements in the construction of this spatiality. The reference description in this work is made through the analysis of a narrative, called Love is deaf, retold by an adult deaf person, fluent in Libras. This narrative was filmed and transcribed following the model proposed in McCleary, Viotti & Leite (2010). Additional adaptations and changes, however, were made in order to capture more adequately the details that were relevant for the purposes of analysis presented here. The use of the following forms to make reference to the characters have been observed: (i) signs; (ii) pointing gestures; and (iii) pantomimes and gestural marks, such as shifts in the position of the torso, head, etc. The elaboration level of nominal forms varies 6 according to the prominence degree of its referent. This analysis reinforces the importance of the spatial organization for reference to characters throughout the narrative, substantially established by the use of gestures in the beginning of each episode.

Launching of digital reference services by academic libraries is on the increase. Libraries are exploring new ways of expanding their services by interacting with users and responding to user inquiries via the Internet, especially students enrolled on the distance mode of studying. The purpose of this study was to evaluate digital reference services at the Polytechnic of Namibia library and the University of Namibia library. Two aspects were evaluated, namely, ‘Resources’ and ‘elements of the general digital reference model’. This study was a summative evaluation study in which semi-structured interviews and observations were used to collect data. The research findings showed that these libraries used the general digital reference model in providing responses to the library users. The study established that the two libraries did not follow the IFLA and RUSA standards of staffing and training of librarians working with digital reference services. The study further found that a lack of ability to fully demonstrate to users how to access various library services was one of the major problems that the librarians experienced. / Program: Masterprogram: Biblioteks- och informationsvetenskap, Digitala bibliotek och informationstjänster

O objetivo desta dissertação é apresentar uma descrição do processo de referenciação em uma narrativa contada em língua de sinais brasileira (libras), partindo da análise de como o sinalizador introduz e retoma as personagens da narrativa. A descrição é feita com base em trabalhos realizados no âmbito da linguística cognitiva, principalmente na proposta de van Hoek (1997) para a descrição da referenciação, e na proposta de Liddell (2003) para a análise da estrutura dos discursos sinalizados. As línguas sinalizadas, de modo geral e especificamente a libras ainda estão em fase inicial de descrição. A questão da referenciação, que diz respeito ao que está por trás do uso de certas formas de codificação dos referentes em determinados pontos do discurso, já foi amplamente discutida em trabalhos sobre línguas orais. Grande parte das análises, entretanto, tem se baseado na linearidade dessas línguas e, assim, a escolha das formas de codificação é explicada pela distância entre menções do referente. Esse tipo de abordagem, no entanto, não parece ser adequado para a análise de línguas sinalizadas, que são línguas de modalidade visual-gestual. Os discursos, nessas línguas, são organizados espacialmente e a referenciação está fortemente associada à organização do espaço de sinalização pelo sinalizador. O modelo de van Hoek, denominado modelo de pontos de referência, torna-se uma ferramenta interessante para a análise do processo de referenciação em línguas sinalizadas na medida em que se baseia em fatores de natureza cognitiva que não se prendem à linearidade do discurso. A autora propõe que alguns nominais funcionam como pontos de referência conceituais que criam domínios semânticos em que estão inseridos outros nominais. Os fatores que determinam a seleção e a extensão de um ponto de referência são, fundamentalmente, sua proeminência conceitual e sua conectividade conceitual. Para a descrição da estruturação da narrativa, foi utilizado o modelo de Liddell (2003) que, analisando a estrutura do discurso em língua de sinais americana (ASL), chamou a atenção para o papel fundamental que a espacialidade tem nos discursos sinalizados e para a importância de elementos gestuais para a construção dessa espacialidade. A descrição da referenciação neste trabalho é feita a partir de uma narrativa, intitulada O amor é surdo, contada por um surdo adulto fluente em libras. A narrativa foi filmada e transcrita de acordo com o modelo proposto em McCleary, Viotti & Leite (2010), sendo que algumas adaptações e mudanças foram feitas, no decorrer da transcrição, de modo a registrar mais adequadamente todos os detalhes de sinalização. 4 A partir da análise da narrativa, foram levantadas as seguintes formas utilizadas para a referência às personagens: i) sinais; ii) gestos de apontamento; iii) pantomimas e marcas corpóreas, como mudanças na posição do tronco, da cabeça, etc. O nível de elaboração das formas nominais varia de acordo com o grau de proeminência de seu referente. Além disso, foi mostrada a importância da organização espacial para a retomada das personagens ao longo da narrativa, substancialmente estabelecida através da gestualidade no início de cada episódio. / This thesis aims at presenting a description of the reference process in a narrative retold in Brazilian Sign Language (Libras), starting with the analysis of how the signer introduces and refers back to the characters in the narrative studied. This description was based on works developed within the Cognitive Linguistics framework, mainly on van Hoek (1997), used for the description of reference, and Liddell (2003), for the analysis of signed discourses. Signed languages particulary Libras are rather understudied, so they are still in an initial description stage. Reference, which regards the use of certain forms for the coding of referents in specific points in the discourse, has already been widely discussed in works on spoken languages. However, most of these analyses have been based on the linearity of these languages and, as a consequence, they have explained the coding form choice in terms of the distance between the mentioning of a referent. This approach does not seem to be appropriate for signed languages, which, being gestural-visual languages, have their discourse spatially organized and their correference relations strongly associated with a signers organization of the signing space. Van Hoeks model, called the Reference Point Model, has proved to be an interesting tool for the analysis of the reference process in signed language, as it is based in cognitive factors that are independent from the linearity of the discourse. The author proposes that some nominals function as conceptual reference points that create semantic domains in which other nominals are embedded. The factors that determine the selection and extension of a point of reference are, crucially, relative conceptual prominence and connectivity. For the description of the narrative structure, Liddell (2003)s model was used. This model, developed on the basis of the analysis of American Sign Language (ASL), highlights the role of spatiality in signed discourses, as well as the importance of gestural elements in the construction of this spatiality. The reference description in this work is made through the analysis of a narrative, called Love is deaf, retold by an adult deaf person, fluent in Libras. This narrative was filmed and transcribed following the model proposed in McCleary, Viotti & Leite (2010). Additional adaptations and changes, however, were made in order to capture more adequately the details that were relevant for the purposes of analysis presented here. The use of the following forms to make reference to the characters have been observed: (i) signs; (ii) pointing gestures; and (iii) pantomimes and gestural marks, such as shifts in the position of the torso, head, etc. The elaboration level of nominal forms varies 6 according to the prominence degree of its referent. This analysis reinforces the importance of the spatial organization for reference to characters throughout the narrative, substantially established by the use of gestures in the beginning of each episode.