Orientador: Antonio Carlos de Moraes / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Educação Fisica / Made available in DSpace on 2018-08-10T17:31:59Z (GMT). No. of bitstreams: 1 Fontes_EduardoBodnariuc_M.pdf: 546789 bytes, checksum: e5cf58e2e5bc2c9f182d7e783137819d (MD5) Previous issue date: 2008 / Resumo: LFNM estabelecido por diferentes períodos de análise do sinal eletromiográfico e comparar os mesmos com a Potência Crítica - PC em indivíduos saudáveis. A amostra foi composta por 17 voluntários saudáveis do sexo masculino (23,4 ± 5,2 anos, 73,6 ± 5,08 kg, 177,8 ± 7,0 cm). Para determinar o LFNM, cada sujeito realizou entre três e quatro cargas constantes no cicloergometro (modelo Corival 400, Quinton Inc, USA) até a exaustão voluntária, com cadência de 60 rpm. Utilizando um eletromiógrafo de 16 canais (MP150, Biopac Systems, Inc., USA), foram coletados sinais EMG do músculo Vasto Lateral. O LFNM foi calculado pelo modelo matemático proposto por (DEVRIES et al., 1982), no qual a taxa de aumento do sinal eletromiográfico atingido durante as cargas constantes é plotado em função das respectivas cargas, sendo o intercepto ¿y¿ do prolongamento desta reta considerado o LFNM. Tal procedimento foi reproduzido para cada um dos tempos de duração de análise, 30 segundos (T30s), um minuto (T1min), dois minutos (T2min) e tempo total (TTotal). PC foi determinada através do modelo hiperbólico. Utilizando a potência de LFNM encontrada por TTotal, foi verificado ainda a capacidade dos voluntários de permanecer em teste retangular de 30 min, sem evidência de fadiga neuromuscular. Foram encontradas diferenças significativas entre os períodos de análise para determinação de LFNM (ANOVA). Utilizando T30s a média alcançada foi 266,7 ± 23,1 W, com T1min ficou em 243,4 ± 16,2 W, para T2min obteve 232,6 ± 18,3 W, e utilizando TTotal a média foi de 217,2 ± 23,1 W, já para PC, foi encontrado valores médios de 177,9 ± 27,3 W. Foram encontradas diferenças estatisticamente significantes entre T30s e todos os outros períodos de análise, T1min, T2min e TTotal (p<0,01). O LFNM determinado com T1min, foi diferente estatisticamente também de TTotal (p<0,01). Todos os períodos de análise utilizados para determinar LFNM superestimaram estatisticamente PC (p<0,01). Foi encontrada correlação significativa apenas para TTotal e PC (R2 = 0,72). Durante o protocolo de carga retangular de 30 minutos, a média da exaustão ocorreu em 661,6 ± 303,9 segundos, apenas um dos voluntários completou os teste de 30 minutos. O nível de significância adotado para todas as análises foi de 5%. A partir dos resultados do presente estudo, é possível concluir que o tempo de análise influencia na determinação de LFNM, superestimando PC e a capacidade de adultos jovens em realizar exercícios de carga constante de 30 minutos em cicloergômetro / Abstract: The purpose of this study was to establish the Neuromuscular Fatigue Threshold - LFNM determinied by different analysis periods of electromyography sign and compare to the Critical Power - CP in healthy young men. 17 healthy men volunteers (23,4 ± 5,2 years, 73,6 ± 5,08 kg, 177,8 ± 7,0 cm) completed three or four constant loads tests on a cycling ergometer to establish LFNM (model Corival 400, Quinton Inc, USA) until exhaustion, and the pedal cadence was 60 rpm. Using an amplifier with 16 channels (MP150, Biopac Systems, Inc., USA), were collected EMG signs from Vastus Lateralis muscle from the dominant side. The LFNM were calculated by the mathematical model proposed by DeVries et al., (1982) where the LFNM was considered the y intercept of the regression line the EMG slopes from contant load tests plotted against its respective load. CP was calculated using the hyperbolic equation model. The LFNM procedure was done by each period of EMG analysis 30 seconds (T30s), one minute (T1min), two minutes (T2min) and total period (TTotal). Using LFNM established by TTotal, were verified the capacity of the volunteers to complete a 30 minutes constant load test, without neuromuscular fatigue. ANOVA found statistical differences between analysis periods. Using T30s, the mean found were 266,7 ± 23,1 W, with T1mn were 243,4 ± 16,2 W, for T2min were 232,6 ± 18,3 W, and with TTotal, the mean were 217,2 ± 23,1 W, however, for CP were found 177,9 ± 27,3 W. Were found statistical differences between T30s and all the others analysis periods, T1min, T2min and Total (p<0,01). The LFNM established by T1min were also different from TTotal (p<0,01). All the analysis periods overestimated PC (p<0,01). Were found significant correlation between only PC and TTotal (R2 = 0,72). During the 30 minutes constant load test completed, the exhaustion mean time were 661,6 ± 303,9 seconds, and only one volunteer completed all the 30 minutes. The significance level adopted for all analysis was 5%. According to the results of this study, it is possible to conclude that the analysis periods influences the determination of LFNM, and it overestimates CP and the capacity of the healthy adults to complete a 30 minutes constant load test in cycling ergometer / Mestrado / Ciencia do Desporto / Mestre em Educação Física

Tendo em vista o crescente investimento em atividades economicamente importantes nas zonas costeiras, tal como a produção petrolífera brasileira e o crescimento na atividade portuária e esforço de pesca, a compreensão adequada dos fenômenos oceanográficos e meteorológicos sobre tais zonas é de grande valia para as operações desses setores. Os ventos representam um importante parâmetro para análise nesse sentido, sendo a principal fonte de energia para a geração de ondas de gravidade nos oceanos, e determinantes na caracterização de condições severas tempo. Uma série de estudos foram desenvolvidos nos últimos anos envolvendo a análise do comportamento dos extremos de ondas sobre a região do Oceano Atlântico Sul, de acordo com o crescimento da demanda por tais informações pelo setor industrial. No entanto, há poucos registros de estudos que caracterizem os extremos de intensidade de vento sobre essa região. E, em nenhum desses trabalhos, a separação direcional do vento extremo e seus fenômenos causadores foram levados em consideração. Dessa forma, o presente trabalho visa atender diretamente a necessidade por trabalhos nesse sentido para a região do Oceano Atlântico Sul, buscando oferecer uma análise dos campos de ventos extremos direcionalmente segregados, através de dados do projeto de reanálise \\textit{NCEP/NCAR Reanalysis I} e de resultados de uma simulação numérica com o modelo BRAMS. A tais conjuntos de dados foi aplicada a metodologia de análise de extremos \\textit{Peaks Over Threshold} (POT), que trata do ajuste dos excessos acima de um limiar estabelecido a uma distribuição conhecida, a Distribuição Generalizada de Pareto (Generalized Pareto Distribution - GPD). E, a partir disso, construir mapas com os valores extremos de retorno para longos períodos. Tais parâmetros são muito importantes na predição de eventos extremos e no refinamento de simulações de longo período. Os extremos relacionados aos fenômenos em larga escala, dados pelos campos do NCEP, em conjunto com o maior detalhamento em mesoescala, dado pelo BRAMS, refletiram diretamente no comportamento dos valores extremos de retorno. Para todas as direções do vento analisadas, observaram-se feições mais refinadas dos extremos de retorno para os resultados com a simulação do BRAMS, principalmente nas zonas costeiras. Essas feições, principalmente àquelas ao sul e sudeste do Oceano Atlântico Sul, tiveram seus valores potencializados em zonas já conhecidas na bibliografia pela grande incidência de eventos altamente energéticos. / Given the growing investment in important economic activities in coastal areas, such as oil and gas exploitation, harbor activities and increasing fishing effort, the proper understanding of oceanographic and meteorological phenomena over such areas has great value to the operations of such sectors. The winds are an important parameter for analysis in this context, being the main source of energy for gravity waves generation in the ocean, and determining the characterization of severe weather conditions. A number of studies have been developed in recent years involving the behavior of extreme waves over the South Atlantic Ocean region, given the rowing demand for such information by industrial sectors. However, there are few records of studies that characterize the extremes of wind speed fields over this region. And, in none of these works, the direction of the extreme wind and meteorological phenomenon associated were considered. Thus, this paper aims to address directly the need for work in this context for the South Atlantic Ocean region, seeking to offer an analysis of extreme wind fields directionally separated, through data from the NCEP/NCAR Reanalysis 1 and results from a numerical simulation with BRAMS. The Peaks Over Threshold (POT), which deals with the adjustment of the excesses above a threshold to the Generalized Pareto Distribution (GPD), was applied to both datasets. And from that, maps with the extreme return values have been developed for long return periods. These parameters are very important in predicting extreme events and refinement of long-period simulations. Extreme winds related to the large scale phenomena, represented by NCEP fields, in conjunction with the greater mesoscale detail, given by the BRAMS simulation, directly reflected in the behavior of extreme return values. For all wind directions analyzed, there were more refined features of the extremes return levels given by the BRAMS simulation, especially in coastal areas. These features, notably those in the south and southeast of the South Atlantic Ocean, values were strengthened in areas already known in the literature for the high incidence of energetic events.

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No. of bitstreams: 1 andesurianedasilva.pdf: 2027818 bytes, checksum: f535a6d847389c90b185ca9271f14e9f (MD5) Previous issue date: 2011-12-14 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Este estudo analisa a transmissão assimétrica de preços no mercado de gasolina brasileiro sobre uma abordagem diferente da existente na literatura nacional, qual seja: a análise desagregada em cidades; a relação dos ajustamentos de preços de gasolina no varejo (postos) em decorrência de variação de preços por atacado (distribuidor); e a relação dos ajustamentos de preços de gasolina no atacado em relação aos preços ministrados nos municípios formadores de preços. Entre as hipóteses sugeridas como principais determinantes destas assimetrias estão o custo de ajustamento e a existência de mercados não competitivos. O objetivo geral deste trabalho se configurou em analisar a dinâmica de preços da gasolina no varejo e no atacado no Brasil sob um enfoque regional, utilizando dados semanais para 134 cidades do país, referentes ao período entre maio de 2004 e fevereiro de 2011. Foram utilizando as abordagens de cointegração por correção dos erros com ajustamentos threshold (TAR) e momentum threshold e (MTAR). Para o caso do varejo, a principal conclusão, para amostra selecionada, é que, há evidência estatística de cointegração entre as séries de preços de gasolina a varejo e atacado em 103 municípios pelo modelo TAR e 96 pelo modelo MTAR. Quanto à questão da assimetria do varejo, tanto pela abordagem do Modelo de Correção de Erros Threshold (ECM TAR) quanto Modelo de Correção de Erros Momentum Threshold (ECM MTAR), concluiu-se que em 70 municípios houve ajustamentos simétricos dos preços. Em termos de distribuição espacial dos resultados do varejo, as regiões Sudeste e Sul apresentaram uma proporção maior de municípios com transmissão simétrica de preços. Este resultado é semelhante aos das regiões Centro Oeste e Norte. Entretanto, na região Nordeste houve uma inversão na proporção de cidades que apresentaram assimetria em relação às demais regiões. Em relação ao atacado, 115 cointegraram pala análise ECM TAR e MTAR com os municípios formadores de preços, os resultados sugerem um alto nível de integração entre estes mercados para os preços praticados pelo atacado da gasolina. Sobre a dinâmica de preços, os resultados mostraram que no atacado são mais fortes as evidências de assimetria com uma proporção com de 45% (52 municípios) dos municípios apresentando relação assimétrica pela abordagem ECM TAR e 27% (32 municípios) pela abordagem ECM TAR. Os resultados tanto do varejo quanto no tacado sugerem um baixo nível de eficiência no processo de transmissão de preços, mesmo os resultados da cointegração sugerindo uma relação comum de longo prazo entre os preços para os dois níveis de mercado, os resultados da assimetria mostraram que esta relação não se da de forma eficiente havendo diferenças nos ajustes de preços para diferentes choques (positivos e negativos). Assim, nem os postos de gasolina repassam de forma eficiente os preços ao consumidor de alterações sofridas no atacado, nem o atacado repassa aos postos de municípios periféricos os preços praticados em grandes mercados consumidores próximos de distribuidoras. / This study analyzes the asymmetric price transmission in Brazilian gasoline markets, discussing a different approach considering the national publications before, as the non aggregated analysis into the cities, retail gasoline price adjustments ratio in (gas stations) due to wholesale prices variation (supplier) and the wholesale gasoline price adjustments ratio comparing the municipalities given the price makers. Among the suggested hypotheses as major determinants of those asymmetries are the adjustment cost and non-competitive markets existence. This work aims to analyze retail and wholesale gas prices dynamics in Brazil under a regional approach, using weekly database for 134 municipalities, between May 2004 and February 2011 period. Cointegration approach for threshold adjustments and momentum threshold error corrections (TAR) and (MTAR) were used. The main conclusion for retail industry is cointegration statistical evidence between retail and wholesale price series in 103 municipalities and 96 by the TAR and MTAR models respectively. For retail asymmetries, TAR Error Correction Model and MTAR Error Correction Model approaches pointed to symmetrical price adjustments in 70 municipalities. In terms of spatial distribution on retail results, southeast and south had a higher proportion of municipalities with symmetrical transmission prices. This result is similar to the North and Midwest regions. However, there was a reversal aspect in northeast region. Cities presented asymmetry considering other regions. Considering wholesale market, 115 municipalities cointegrated by ECM TAR and ECM MTAR approach with the price makers municipalities. Results suggest a higher level of integration between these markets for the gasoline wholesale prices. By price dynamics analysis, asymmetry evidences are stronger with a 45% proportion (52 municipalities) introducing asymmetric relationship by ECM TAR approach and 27% (32 municipalities) by ECM TAR approach. Both retail and wholesale results suggest a low efficiency by price transmission process. Cointegration results also suggest a common long-term relationship between prices in retail or wholesale levels. This relation by asymmetry results is not settled efficiently. There are differences in price adjustments to different shocks (positive and negative). Thus, no gas stations transfers efficiently prices to consumers considering market changes and by last, nor the wholesale market transfers to peripheral municipalities gas stations those existing prices in big markets near the suppliers.

Les études sur les capacités cardiorespiratoires de femmes atteintes de fibromyalgie (FM) présentent des résultats contradictoires. De plus, aucune étude n’a évalué les capacités à reproduire les mesures physiologiques cardiorespiratoires de cette population, 24 heures suivant un test d’effort maximal. Objectifs : Les objectifs de cette étude étaient les suivants: 1) de décrire la capacité cardiorespiratoire de femmes atteintes de FM et 2) de décrire leurs capacités à reproduire les mesures physiologiques cardiorespiratoires 24 heures suivant une épreuve d’effort cardiorespiratoire maximal. Méthodes : Douze femmes FM ont été soumises à deux épreuves d’effort cardiorespiratoire maximal (T1 et T2) sur tapis roulant (protocole BSU/Bruce ramp) à 24 heures d’intervalle, jusqu’à épuisement. La collecte des échanges gazeux et ECG ont été faites de façon continue tout au long des deux tests. Le lactate sanguin, la pression artérielle, l’intensité de la douleur et la perception de la difficulté à l’effort ont également été évalués. Le Questionnaire révisé sur l’impact de la fibromyalgie (QRIF), l’Échelle de kinésiophobie de Tampa, version canadienne-française (EKT-CF), et le questionnaire international sur le niveau d’activité physique, version canadienne-française (IPAQ) ont été utilisés afin de mieux décrire les caractéristiques des participantes. Des procédures statistiques non paramétriques ont été utilisées pour les besoins d’analyses statistiques. Résultats : En comparant les résultats du volume d'oxygène crête (VO2crête) obtenus au T1 aux valeurs normatives, 75% des participantes se situaient sous la catégorie “Passable”, dont 25% sous le seuil de la catégorie “Très pauvre”. Toutefois, en considérant le niveau de sévérité de la FM et comparant les participantes légèrement et modérément affectées au T1 et T2, les résultats ont démontré une différence significative de la VO2crête au T2 (30,4 ± 3,3 vs 22,9 ± 4,7 ml O2·min−1·kg−1) et de la VO2 au seuil anaérobie ventilatoire (VO2SAV) au T1 (24,0 ± 4,0 vs 18,5 ± 4,4 ml O2·min−1·kg−1) et T2 (24,9 ± 3,2 vs 18,7 ± 4,5 ml O2·min−1·kg−1). Finalement, aucune différence significative au niveau de la VO2crête (25,5 ± 5,3 vs. 26,5 ± 5,3 ml O2·min−1·kg−1, p > 0,05) et de la VO2SAV (21,2 ± 4,8 vs. 21,7 ± 4,8 ml O2·min−1·kg−1, p > 0,05) n’a été observée entre T1 et T2. Conclusion : Soixante-quinze pour cent des participantes avaient une capacité cardiorespiratoire inférieure à celle de la population générale. De plus, les capacités cardiorespiratoires des participantes semblent être affectées par le niveau de sévérité de la FM. Finalement, les résultats de cette étude ne démontrant pas de différence significative des capacités cardiorespiratoires entre T1 et T2, suggèrent qu’il n’y a pas de difficulté à reproduire les mesures physiologiques 24 heures suivant le premier test d’épreuve maximale. / Abstract: Studies on cardiorespiratory fitness (CRF) among women with fibromyalgia (FM) has been documented with some contradictory results. Furthermore, no research has looked at the capacity to reproduce the cardiorespiratory physiology measurements 24 hours following a maximal CRF test, in FM patients. Objectives: The objective of this study was twofold: 1) to describe the cardiorespiratory fitness of women with fibromyalgia (FM); and 2) to describe the reproducibility of cardiorespiratory physiological parameters 24 hours following a maximal exercise test. Method: Twelve FM women underwent two maximal exercise tests (T1 and T2) on a treadmill (BSU/Bruce ramp protocol) 24 hours apart, until volitional exhaustion. Gas exchange and ECG were continuously monitored during both tests. Blood lactate, blood pressure, pain intensity and rate of perceived exertion, were also assessed. The Revised Fibromyalgia Impact Questionnaire (FIQR), the Tampa Scale of Kinesiophobia (TSK-CF) and the International Physical Activity Questionnaire (IPAQ) were used to further characterize the participants. Non-parametric statistical procedures were used for statistical analysis. Results: When comparing the peak oxygen uptake (VO2peak) results to normative values at T1, 75% of the participants were below the “Fair” category, of which 25% were below the “Very Poor” category. However, when taking into consideration the FM severity level and comparing mildly to moderately affected participants at T1 and T2, the results showed a significant difference in VO2peak at T2 (30.4 ± 3.3 vs 22.9 ± 4.7 ml O2·min−1·kg−1) and in VO2 at ventilatory anaerobic threshold (VO2VAT) at T1 (24.0 ± 4.0 vs 18.5 ± 4.4 ml O2·min−1·kg−1) and T2 (24.9 ± 3.2 vs 18.7 ± 4.5 ml O2·min−1·kg−1). Finally, no significant differences in VO2peak (25.5 ± 5.3 vs. 26.5 ± 5.3 ml O2·min−1·kg−1, p > 0.05) and VO2VAT (21.2 ± 4.8 vs. 21.7 ± 4.8 ml O2·min−1·kg−1, p > 0.05) were found between T1 & T2. Conclusion: Seventy-five percent of the participants had a cardiorespiratory fitness level lower than the general population. Furthermore, the cardiorespiratory capacities of the participants seemed to be affected by their FM severity level. Finally, the results of this study showed no significant difference in cardiorespiratory fitness between T1 and T2, therefore indicating no cardiorespiratory difficulty to reproduce the physiological measurements 24 hours following a maximal exercise test.

This qualitative research aims to identify the threshold concepts in financial instruments using Meyer and Land's Threshold Concept Framework (2005) and applies the dimension of Semantics and Legitimation Code Theory (Maton, 2014) to analyse whether semantic gravity and semantic density are stronger or weaker in the threshold concepts. The analysis points to five threshold concepts in the financial instruments module. It further aims to explore whether African, Coloured and Indian students' exposure to these threshold concepts results in troublesome knowledge and/or transformation in understanding and thinking in a second-year Accounting course at a South African university. Triangulation is used to confirm the authenticity and consistency of the data emerging from the identification of the threshold concepts. Using Semantics, this research illustrates that the five threshold concepts possess weaker semantic gravity due to the abstract nature of the threshold concepts and stronger semantic density is present due to the complex and dense terminology inherent in financial instruments. Evidence from a general survey, interviews and summative assessments conducted with students registered for an Accounting course shows that exposure to the threshold concepts resulted in troublesome knowledge and/or transformed understanding. Identifying the threshold concepts could make specialised Accounting knowledge more explicit to students and exploring the knowledge experienced as troublesome and the transformed understanding experienced provides room for debate around pedagogy and curriculum reform.

No description available.

Animal models are used extensively in voice research to study aspects of phonation, including physiology, kinematics, structure, and histology. Animals such as dog, cow, pig, sheep, deer, monkey, ferret, and rabbit have been used in voice research, with pig being one of the most common models. It is thought that the pig larynx is highly similar to the human larynx and one of the best models used in animal translational research. As with any model, however, the pig larynx does have some limitations. Perhaps a limitation most important to the rationale of this investigation is that pigs are difficult animals to study in vivo. Maintenance for a pig is challenging due to its large size and the variability of phonation use in the animal. Therefore, viable and practical alternatives are needed for in vivo voice research. The current study collected preliminary normative data from an alternate animal model, the rabbit, which has been used more recently in studies to model human phonation. The rabbit model was chosen due to its histological similarities to humans, in vivo phonation patterns, size, and practicality. The rabbit represents a more practical model for some longitudinal designs, as well as ex vivo phonatory models with aerodynamic measures as the primary variables. The current study involved a comparison of two aerodynamic measures, specifically phonation threshold pressure (PTP) and phonation threshold flow (PTF) between two groups, pig and rabbit larynges. The purpose of this study was to determine normative aerodynamic values for rabbits and to compare these with normative values for pigs during excised larynx benchtop phonation. Each group consisted of 15 larynges that were finely dissected to reveal the true vocal folds. Each larynx was then connected to a pseudolung and humidified air was passed through it. Fifteen phonation trials were elicited and the results averaged for each larynx. The results indicated that PTP and PTF were significantly different between the two groups, with PTP and PTF being lower for the rabbit group. Additionally, PTP values for rabbits were closer than pigs to the typical human value; however, some methodological challenges to rabbit benchtop models, including size and structural integrity, also exist. But the results from this study indicate that rabbits should be considered a viable option for voice research that would be more feasible with a small animal option that translates well to humans than a large animal option.

This thesis is part of a larger series of studies being conducted by Kristine Tanner, PhD, Associate Professor in the Department of Communication Disorders at Brigham Young University (BYU). The larger project is funded by the National Institute on Deafness and Other Communication Disorders at the National Institutes of Health. This thesis primarily investigated the effects of combination inhaled corticosteroids (ICs) on aerodynamic measures of the voice. In recent years, an increase in the localized laryngeal side effects from IC treatment, including dysphonia, have been reported. This study employed a between-groups experimental design, with two groups of rabbit larynges having been exposed to either ICs or nebulized isotonic saline two times each day for eight weeks at The University of Utah. For this study, the independent variable is group condition (i.e., IC versus saline) and the dependent variables are two aerodynamic measurements made at the onset of phonation using a benchtop experimental setup, namely phonation threshold pressure (PTP; cmH2O) and phonation threshold flow (PTF; L/min). The results of this study indicate a significant difference in PTP and PTF between vocal folds treated with IC as compared to vocal folds treated with nebulized isotonic saline solution. Implications of this study suggest negative changes in the voice due to IC treatment.

Thesis (Doctor of Radiography)--Cape Peninsula University of Technology, 2020 / Radiation therapy has undergone significant changes with regard to new medical imaging technologies, including computerised tomography (CT) and magnetic resonance imaging (MRI). Practitioners now have access to technologies that provide anatomical information in an infinite selection of views. Earlier advances in three-dimensional conformal radiation therapy (3D-CRT) allowed for the site of treatment to be accurately located. Intensity modulated radiotherapy (IMRT) enabled practitioners to accurately focus the ionising radiation beam, while modulating the intensity of the dose being administered. Currently, using image-guided radiotherapy (IGRT) methods, radiation therapists can track the effectiveness of treatment in real-time to provide better protection for the organs and tissue that are not targeted for treatment. The changes described above have fundamentally changed radiation therapy practice, and thus have implications for the training of radiation therapists. This thesis argues that without a deep understanding of the science underpinning the advancements in radiation therapy techniques, practitioners will be unlikely to achieve the necessary level of accuracy and consistency in treatment. Radiation physics concepts, such as sources and types of ionising radiation, ionisation, the isocentre and the Inverse Square Law underpin competent and safe practice. Threshold concepts, such as those listed above, have been identified as concepts that pose difficulty to students due to its complexity and the increased levels of cognitive challenge required to master a threshold concept. In applied disciplines, such as radiation physics, threshold concepts are strongly associated with competent practice. This study focused on the first year radiation physics curriculum and addressed the overarching research question: What is the relationship between threshold concepts in the radiation physics curriculum and radiation therapy practice? The study was guided by a translation device that combined two conceptual frameworks namely the Threshold Concept Framework and Legitimation Code Theory’s (LCT) Semantics dimension. LCT is a knowledge base theory that explains the complexity of knowledge structures. The Semantics dimension provided an explanation of the difficulty of concepts and proposed five pedagogies for the cumulative learning of complex concepts. A case study research design and methodology guided the research process. Data for the study comprised curriculum documents, and semi structured focus group and individual interviews with students, academic staff and clinical educators. The data were analysed using a translation device to show the semantic profile of curriculum documents, pedagogies and participants’ different understandings of the threshold concepts in radiation physics. The study found that threshold concepts in radiation physics underpin competent and safe practice. An external language of description was developed to identify the characteristics of threshold concepts. A virtual clinical environment was proposed as one of the pedagogies to aid mastering of threshold concepts through visualisation of the unseen by facilitating students’ understanding of threshold concepts for competent and safe radiation therapy practice. The study showed that students’ mastery of threshold concepts in radiation physics is critical for practice.

The effect of time on taste threshold was examined in 30 diabetics and 30 control subjects (ages 22-30) who had participated in a sensory study 14 years previously. Detection and recognition taste thresholds for sweet (sucrose), salty (sodium chloride), sour (citric acid), and bitter (quinine sulfate) were assessed using triangle testing. Food preferences related to concentration of the stimuli in model food systems were tested using a nine-point hedonic scale. Mashed potatoes were used as the carrier for different levels of salt. A beverage composed of water, sucrose, and citric acid was varied to measure preferences for sweet and sour tastes. Demographic, health status, and selected dietary and food consumption information were also obtained. In the initial study, the diabetic group had higher detection and recognition thresholds for sweet, salty, and bitter stimuli than the control group. Although the control group still had lower thresholds for most of the stimuli (except for recognition of sour and salty), the majority of the diabetics either remained at their same taste sensitivity or improved their ability to perceive the stimuli over the 14-year period. With the exception of recognition of bitter by diabetics, both groups improved in their ability to identify taste sensations with age. Overall, the diabetic group became better at detecting sweet, sour, and salty taste stimuli between 1977 and 1991. They also became more sensitive to recognizing sweet and salty taste stimuli. For each set of food samples, a significant relationship existed between rating and sample. Samples with moderate levels of sodium chloride, citric acid, or sucrose were the most preferred . There was not a significant difference between the diabetic and control groups in their rating of the samples. Diabetic and control groups did not rate the samples significantly different. Additionally, threshold was not related significantly with rating of mashed potato samples or beverage-sour solutions. However, sucrose recognition thresholds and preference for sucrose concentration in beverage-sweet solutions were significantly related. Subjects with higher threshold values tended to rate the samples with higher concentrations of sucrose higher. There were no noteworthy correlations between the reported levels of salt consumption and salt thresholds, between sugar consumption and sucrose thresholds, nor between liking sour foods and citric acid thresholds.