Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal

The growing share of installed wind power in the Swedish electricity system has caused concerns whether the available regulating power will be sufficient. Several studies have examined the need of regulating power using both statistical and modelling approaches. However, there is a risk that some aspects of the short-term regulation of hydropower might have been missed. By using one of Vattenfall’s hydropower planning tools, the short-term operation of The Lule River has been simulated with an increasing penetration of wind power. The tool includes detailed models of reservoirs, generating units including efficiency curves and start/stop costs. By introducing a day-by-day simulation with a seven-day window price forecast, updated with a new wind forecast for each iteration, a 21-days scenario has been simulated. Transmission limits are disregarded and the thermal production is reduced with the average wind production. To quantify and compare the regulation capacity, the regulation factor is introduced. It reflects the ability to utilise high-price hours and considering that the need of regulating power for the short-term perspective is reflected in the price it will also reflect the regulation capacity. It is shown that the regulating factor is correlated to the discharge factor,whichis the relation between the maximum discharge to the average statistical discharge for a plant. A high discharge factor provides the flexibility to utilise the fluctuations in price. The discharge factor is adapted to the plants placement in the reach, accounting for both reservoirs located upstream and downstream, especially for The Lule River which has been designed to regulate for the fluctuations in the load. The flexibility required by the rest of the Nordic rivers is quantified for future studies. It is concluded that The Lule River is able to meet some of the fluctuations of wind power production due to the overcapacity ininstalled power. The production can, at the expense of decreased efficiency of the generating units, alter the production to suit a more fluctuating price.It is important to emphasise that The Lule River alone cannot balance a large penetration of wind power. To fully take into account the effects of a large penetration of wind power the study must be expanded to include more scenarios. The study should include different types of hydrological prerequisites and the seasonal variations in power production as well as additional rivers.

[Truncated abstract] Broadly, research literature on the physiological aspects of water polo game play is limited, but particularly so in the women's game. Moreover, significant changes to game rules in recent years are likely to have had an impact on the game demands. Therefore, this research project sought to investigate the physiological characteristics of contemporary elite female water polo players and the demands of match play. Overall, the five studies comprising this thesis aimed to improve the practical knowledge of coaches and sport scientists concerning the training and monitoring of players. Study one (Chapter 3) compared two water polo-specific field tests of aerobic and/or match fitness (MSST, multistage shuttle swim test; and WIST, water polo intermittent shuttle test) with a traditional incremental swimming test to exhaustion (IST, 5 x 200 m). Prior to this study, the physiological responses to the MSST and WIST were not well understood. Additionally, the degree of association between these two tests was unknown. Therefore, 14 Australian National Women's Water Polo Squad players performed the MSST and WIST, and 13 players from a National Water Polo League club performed the MSST, WIST and IST, on separate occasions. Peak heart rate, blood lactate and ratings of perceived exertion were obtained for all tests. Expired air was collected post test for the National League players. The results showed that the National Squad players performed significantly better in the MSST (636 ± 114 vs. 437 ± 118 m, p < 0.001) and WIST (270 ± 117 vs. 115 ± 57 m, p < 0.001) than the National League players. ... Absolute decrement yielded TE of 0.55 s (-0.42-0.81), CV of 26.0% (19.3-41.0) and ICC of -0.002 (-0.44-0.44). Relative (%) decrement yielded TE of 1.6% (1.2-2.3), CV of 27.2% (20.1-42.9) and ICC of -0.02 (-0.46-0.42). Results indicate that total time was a reliable measure, whilst decrement was not. Similar to land-based RSA tests, total time should be the criterion measure of performance in the RST. The RST can form part of a specific battery of field tests for water polo, and can also be used as a conditioning tool. The final study (Chapter 7) was a nutritional-intervention study. Based on the time-motion data from study three, a 59-min match simulation test (MST) was designed to mimic the activity profiles and physical demands of water polo match play. Using a randomized cross-over double-blind design, 12 Australian National Women's Water Polo Squad players ingested 0.3 g·kg-1 of NaHCO3 or placebo, 90 min before performing the MST, which included 56 x 10-m maximal-sprint swims as the performance measure. Although pre-exercise ingestion of NaHCO3 was effective in enhancing extracellular pH and bicarbonate levels, the percentage difference in mean sprint times between trials showed no substantial effects of NaHCO3 (0.4; ±0.9%, effect size = 0.09; ±0.23, p = 0.51). The results suggest that elite water polo players should not expect enhancement in intermittent-sprint performance from NaHCO3 supplementation. These findings are contrary to previous NaHCO3 studies on simulated team-sport performance, but this investigation is unique in that it examined highly-trained athletes performing sport-specific tasks. In conclusion, the findings of this thesis add to the existing literature on the applied physiology of women's water polo. It is hoped that the knowledge gained from these findings will lead to more appropriate conditioning, testing and selection outcomes.

Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-06-13T12:44:06Z No. of bitstreams: 1 TARCÍZIO NASCIMENTO - TESE PPGEA 2009..pdf: 10510162 bytes, checksum: 327d8ac96a0edae285a8bd59ae917da5 (MD5) / Made available in DSpace on 2018-06-13T12:44:06Z (GMT). No. of bitstreams: 1 TARCÍZIO NASCIMENTO - TESE PPGEA 2009..pdf: 10510162 bytes, checksum: 327d8ac96a0edae285a8bd59ae917da5 (MD5) Previous issue date: 2009-08 / CNPq / Este trabalho foi conduzido no campo experimental de Bebedouro, pertencente à Empresa Brasileira de Pesquisa Agropecuária (Embrapa Semiárido) com o objetivo de determinar a intermitência de irrigação e a vazão do emissor que reduzindo a velocidade da frente de umidade no perfil do solo; e sua influência nas perdas de água por percolação. O trabalho foi realizado em um lisímetro de drenagem com dimensões de 100 cm de aresta, utilizando-se um solo tipo Neossolo Quartzarênico, com 94% de areia, 1% de silte e 5% de argila, coletado em uma área no projeto de irrigação Senador Nilo Coelho, em Petrolina-PE. Com base na evaporação média anual da estação experimental Bebedouro, que é de aproximadamente 8,0 mm, os testes foram realizados, utilizando um volume de reposição, fixo de 8,0 L de água. As irrigações foram realizadas, utilizando-se um esquema fatorial de quatro vazões (2,0; 4,0; 8,0 e 12,0 L h"1) por quatro intermitências (uma, duas, três e sem intermitências). Cada teste foi repetido por três dias consecutivos com irrigação, e quatro dias consecutivos sem irrigações. A velocidade da frente de umidade no solo irrigado com o emissor de 12,0 L h"1 foi, respectivamente, de 110,0; 89,9; 77,5; e 73,6 cm h"1 para irrigação sem, com uma, duas e com três intermitências. Com o emissor de 8,0 L Iv a velocidade foi de 68,1; 62,3; 60,4 e 62,6 cm h'1. Com o emissor com 4,0 L h"1 a velocidade foi de 47,6; 39,2; 36,6; e 39,7 cm h"1. Com o emissor com 2,0 L h"1 a velocidade foi de 34,7; 25,1; 23,0 e 28,3 cm h'1. Nas irrigações realizadas com emissores de vazão de 12,0 L h"1, observa-se, em relação à intermitência, que a velocidade da frente de umidade sofreu um decréscimo de 18,73; 29,86 e 33,39 %, entre as irrigações sem intermitência e as irrigações com uma, duas e três intermitências, respectivamente. Nas irrigações realizadas com emissores de vazão de 8,0 L h~1, houve um decréscimo de 8,58; 11,31 e 8,08%, nas irrigações realizadas com emissores de vazão de 4,0 L h"\ houve um decréscimo de 17,65; 23,11 e 16,60% e nas irrigações realizadas com emissores de vazão de 2,0 L h'1, houve um decréscimo de 27,67; 33,72 e 18,44%. Em relação à vazão, observase que a velocidade da frente de umidade nas irrigações realizadas sem intermitência, sofreu um decréscimo de 38,37; 56,92 e 68,60%, entre as irrigações com emissores de 12,0 L h"1 e as irrigações com emissores de 8,0; 4,0 e 2,0 L h"1 respectivamente. Nas irrigações realizadas com uma intermitência, houve um decréscimo de 30,62; 56,35 e 72,05%, nas irrigações realizadas com duas intermitências, houve um decréscimo de 22,06; 55,77 e 70,32% e nas irrigações realizadas com três intermitências, houve um decréscimo de 14,95; 46,06 e 61,55%. Com base nos resultados, observa-se que as menores velocidades da frente de umidade ocorreram nas irrigações com duas intermitências e com emissores de 2,0 e 4,0 L h"1. A redução na velocidade da frente de umidade aumenta o tempo de permanência da água no perfil do solo, proporcionando um maior tempo de oportunidade para extração da água pela cultura, aumentando a eficiência de uso da água, e reduzindo as perdas por percolação profunda. / This study was conducted in the Bebedouro experimental field, belonging to the Brazilian Agricultural Research Corporation (Embrapa Semi-Arid) in order to determine the irrigation intermittency and the emitter flow that would reduce the front velocity of moisture in the soil profile, and its influence on deep percolation water loss. The study was conducted in a drainage lysimeter with dimensions of 100 cm of edge, using a soil type Entisols, with 94% of sand, 1% of silt and 5% of clay, collected in a commercial area of a Grape production farm in the irrigation project Senador Nilo Coelho Petrolina-PE. Based on the average annual evaporation of the Bebedouro experimental station, which is approximately 8.0 mm, the tests were conducted using a fixed replacement volume of 8.0 L of water. The irrigations were performed using a factorial scheme of four flow rates (2.0, 4.0, 8.0 and 12.0 L h"1) by four irrigation intermittencies (one, two, three and without intermittency). Each test was repeated three consecutive days with irrigation and four consecutive days without irrigation. The front velocity of moisture in the soil irrigated with the emitter of 12.0 L h"1 was, respectively, 110.0, 89.9, 77.5, and 73.6 cm h"1 without irrigation, with one, two and three intermittencies. With the emitter of 8.0 L h"1 the front velocity was 68.1, 62.3, 60.4 and 62.6 cm h"1. With the emitter with 4.0 L h"1 the front velocity was 47.6, 39.2, 36.6, and 39.7 cm h"1. With the emitter with 2.0 L h"1 the front velocity was 34.7, 25.1, 23.0 and 28.3 cm h"1. In the irrigation performed with the emitters of flow rate of 12.0 L h", it is observed, in relation to intermittency, that the front velocity of the moisture decreased by 18.73, 29.86 and 33.39% between the irrigations without intermittency and irrigation with one, two and three intermittencies, respectively. In irrigations performed with emitters of flow rate of 8.0 L h", there was a decrease of 8.58, 11.31 and 8.08%, in irrigations performed with emitters of flow rate of 4.0 L h"1, there was a decrease of 17.65, 23.11 and 16.60% and in the irrigations performed with emitters of flow rate of 2.0 L h", there was a decrease of 27.67, 33.72 and 18.44%. Regarding flow, it is observed that the front velocity of moisture in irrigations performed without intermittency, decreased by 38.37, 56.92 and 68.60% between the irrigations with emitters of 12.0 L h"1 and the irrigations with emitters of 8.0, 4.0 and 2.0 L h"1 respectively. In irrigations performed with one intermittency, there was a decrease of 30.62, 56.35 and 72.05%, in irrigations performed with two intermittencies, there was a decrease of 22.06, 55.77 and 70.32%, and in the irrigations performed with three intermittencies there was a decrease of 14.95, 46.06 and 61.55%. Based on the results, it is observed that the lower velocity of moisture occurred in the front with two intermittencies and irrigation with emitters of 2.0 and 4.0 L h"1. The reduction in the front velocity of the soil moisture increases the residence time of water in the soil profile, providing a greater opportunity time for water extraction by the crop, increasing the efficiency of water use, and reducing deep percolation losses.

Le syndrome d’apnées obstructives du sommeil (SAOS) est associé à la survenue de neuropathies optiques, en particulier la neuropathie optique ischémique antérieure aigue non artéritique (NOIAA-NA). Parmi les mécanismes d’apparition de cette neuropathie et potentiellement associés au SAOS, la dysrégulation et l’inflammation vasculaires pourraient jouer un rôle. Il n’existe aucune donnée dans la littérature sur l’effet de l’hypoxie intermittente (HI) chronique sur la fonction vasculaire de l’œil.Le but de ce travail était de développer des techniques d’évaluation de la fonction vasculaire oculaire chez le rat et de les appliquer à l’étude des conséquences vasculaires oculaires de l’HI. Ainsi, deux approches complémentaires ont été développées : 1) un prototype de fluxmètre laser Doppler (LDF) adapté au rongeur pour l’évaluation in vivo de la perfusion sanguine rétinienne et de la tête du nerf optique (TNO) et 2) le modèle d’étude de l’artère ophtalmique (AO) du rat par myographie vasculaire, in vitro.La mise au point du LDF chez le rat sain a permis de valider la pertinence du signal provenant des artères rétiniennes. A l’inverse, nos données invalident l’intérêt de la mesure au niveau de la TNO. En réponse à l’inhalation d’oxygène pur, nous observons une diminution de 17,0 ± 13,7 % de la vélocité artérielle rétinienne (VelART). Nous n’observons pas de variation significative de VelART lors d’injection intra-carotidienne d’endothéline 1 (ET-1) malgré une forte vasoconstriction des vaisseaux rétiniens. Les perspectives consistent à associer une caméra de haute résolution à un système bidirectionnel de LDF. L’étude de la réactivité de l’AO par myographie chez le rat soumis à 14 jours d’HI a mis en évidence une augmentation de la contraction à l’ET-1, associée à une augmentation de la réponse médiée par les récepteurs de type A (ETRA)et à une surexpression des ETRA au sein de l’AO. La relaxation NO-dépendante était diminuée chez le rat HI, et associée à un effet prédominant des produits vasoconstricteurs du cytochrome P450. Ces réponses étaient associées à une augmentation de la présence d’anions superoxyde dans la paroi de l’AO. Des études complémentaires sont nécessaires pour explorer les mécanismes à l’origine des ces altérations vasculaires, en particulier le rôle du stress oxydant. / Obstructive sleep apnea (OSA) has recently been associated with the occurrence of optic neuropathies, especially acute non-arteritic anterior ischemic optic neuropathy (NAION). Among the mechanisms of NAION onset potentially associated with OSA, vascular dysregulation and inflammation may play a role. There is still no data on the effect of chronic intermittent hypoxia (IH) on vascular function of the eye. The purpose of this work was to develop techniques for assessing rat ocular vascular function and apply them to the study of the ocular vascular consequences of IH. Thus, two complementary models have been developed: 1) a laser Doppler flowmeter (LDF) prototype adapted for rodents, to evaluate in vivo retinal and optic nerve head (ONH) blood perfusion and 2) in vitro model of rat ophthalmic artery (OA) study by myography. Preliminary work on healthy rat enabled us to validate the relevance of retinal arteries LDF signal, but not that of the ONH. Retinal blood velocity (VelART) dropped by 17.0 ± 13.7% in response to pure oxygen inhalation. We did not observe any significant change in VelART signal after intracarotidian endothelin 1 (ET -1) injection, despite strong vasoconstriction of retinal vessels. OA reactivity study by myography in rats exposed to a 14-day IH showed increased contraction to ET-1, associated with an increased endothelin receptor A-mediated (ETRA) response and ETRA overexpression within the AO. NO-dependent relaxation is reduced in IH rats, and associated with a shift towards vasoconstrictive effects of cytochrome P450 products. These responses were associated with an increase in superoxide anions in the OA wall. Further studies are needed to explore the underlying mechanisms of these vascular changes, particularly the role of oxidative stress. Understanding of the LDF signal is partial and should be further explored to permit application to the study of IH rat.

Le syndrome d’apnées obstructives du sommeil (SAOS) est associé à une forte morbi-mortalité cardiovasculaire. L’hypoxie intermittente (HI), conséquence majeure des apnées, est à l’origine d’un stress oxydant, d’une activation de HIF-1 (hypoxia inducible factor 1) et d’une expression d’endothéline (ET-1), tous impliqués dans les complications cardiovasculaires liées à l’HI.Dans un premier temps, nous avons démontré que l’HI augmentait l’incidence des arythmies ventriculaires létales associées à l’ischémie myocardique. Parmi les mécanismes potentiels impliqués, l’analyse spectrale de la variabilité de la fréquence cardiaque et de la pression artérielle et le dosage des catécholamines ont mis en évidence une activation sympathique chez les animaux exposés à l’HI. L’HI est également à l’origine d’altérations de la repolarisation ventriculaire (allongement du QTc et du Tpeak-Tend) et d’une dispersion du gradient transmural (allongement de la durée du potentiel d’action endocardique) associées à une augmentation de l’expression de canaux calciques de type LTCC et TRPC dans l’endocarde.Dans la seconde partie de ce travail de thèse, nous nous sommes intéressés aux perturbations de l’homéostasie du zinc en réponse au stress oxydant causé par l’ischémie-reperfusion (IR) ou par l’HI et aux propriétés cardioprotectives de la supplémentation en zinc dans ce contexte. Nous avons montré que l’IR et l’HI induisaient une diminution des concentrations de zinc myocardiques et plasmatiques, respectivement. Nous avons mis en évidence les effets bénéfiques de la supplémentation en zinc vis-à-vis des arythmies ventriculaires et des altérations myocardiques induites par l’IR. L’administration de zinc lors de la reperfusion a également permis d’abolir l’augmentation de la taille d’infarctus induite par l’exposition chronique à l’HI.Finalement, nous avons étudié les effets de la déplétion en zinc sur des cellules endothéliales à l’aide d’un chélateur spécifique du zinc, le TPEN. Nous avons observé que l’exposition des cellules au TPEN entraînait une translocation nucléaire de HIF-1α et une augmentation de la sécrétion d’ET-1 avec, comme conséquence, une augmentation de la capacité migratoire des cellules endothéliales. Ainsi, une déplétion en zinc semble conduire à une activation de l’axe HIF-1-ET-1 connu pour ses effets délétères lors de l’HI.En résumé, l’exposition chronique à l’HI exacerbe les arythmies et augmente la taille d’infarctus lors de l’IR. L’activation sympathique, le stress oxydant et l’altération de l’homéostasie du zinc pourraient être impliqués. L’utilisation d’outils pharmacologiques permettrait de confirmer leur rôle et potentiellement de prévenir les altérations cardiovasculaires liées à l’HI et au SAOS. / Obstructive sleep apnea (OSA) is associated with increased cardiovascular morbidity and mortality. Intermittent hypoxia (IH), one of the major consequences of apneas, leads to oxidative stress, activation of HIF-1 (hypoxia inducible factor 1) and endothelin (ET-1) expression, all known to play an important role in the cardiovascular consequences of OSA.First, we have demonstrated that IH increases the incidence of ischemia-related lethal ventricular arrhythmias. Among the potential mechanisms involved, spectral analysis of heart rate and blood pressure variability and catecholamine assay, showed a sympathetic activation in animals exposed to IH. IH was also responsible for alterations in ventricular repolarisation (increased QTc and Tpeak-Tend intervals) and dispersion of the transmural gradient (increased endocardial action potential duration). These alterations were associated with increased expression of endocardial LTCC and TRPC calcium channels.The second part of the thesis aimed at investigating zinc homeostasis in response to the oxidative stress induced by ischemia-reperfusion (IR) or IH as well as the beneficial effects of zinc supplementation in this context. We observed that IR and IH induced a decrease in myocardial and plasma zinc concentrations, respectively. We also highlighted the protective effects of zinc supplementation during reperfusion against the ventricular arrhythmias and myocardial dysfunction induced by IR. Zinc administration during reperfusion also abolished the increase in infarct size induced by chronic IH exposure.Finally, we investigated the effects of zinc depletion in endothelial cells exposed to TPEN, a specific zinc chelator. We observed that TPEN induced a nuclear translocation of HIF-1α and an increase in ET-1 secretion with a resulting increase in endothelial cell migration. Thus, zinc depletion appears to promote activation of the HIF-1-ET-1 axis, known for its deleterious effects upon IH.In summary, chronic IH exposure enhances ventricular arrhythmias and increases infarct size upon myocardial I/R. Sympathetic activation, oxidative stress and alterations of zinc homeostasis appear to be contributing factors. Pharmacological targeting of these alterations should be performed in order to confirm their role as well as to potentially prevent the deleterious cardiovascular consequences of IH and OSA.

Le syndrome d’apnées obstructives du sommeil (SAOS) est un problème de santé publique majeure affectant 6-13% de la population d’âge moyen. Des études épidémiologiques et l’accumulation de données cliniques ont montré que le SAOS joue un rôle important dans l’initiation et la progression des pathologies cardiovasculaires (CV) comme l’infarctus du myocarde (IM). Les patients hospitalisés post-IM présentent une prévalence pour le SAOS de l’ordre de 50%. De plus, le SAOS augmente la vulnérabilité du cœur à l’infarctus, ce qui se traduit par une taille d’IM plus grande, une ischémie myocardique prolongée, et une aggravation des évènements cardiovasculaires au long-terme, prédisposant les patients apnéiques à des infarctus surnuméraires, à l’insuffisance cardiaque (IC) et au décès. Il semble donc important de comprendre précisément les mécanismes impliqués dans cette susceptibilité accrue à l’ischémie myocardique afin de proposer de nouvelles cibles thérapeutiques et améliorer la prise en charge du risque CV chez les patients apnéiques. L’hypoxie intermittente chronique (HI) est le substrat physiopathologique majeur des complications CV du SAOS via l’activation de mécanismes physiopathologiques variés, tels que l’inflammation, le stress oxydant ou encore l’activation sympathique. Ce travail de thèse avait pour but de 1) caractériser la réponse aigue et chronique à l’IM chez des animaux exposés à l’HI, 2) de disséquer les mécanismes cellulaires impliqués dans la susceptibilité accrue à l’IM chez ces mêmes animaux.Nos travaux ont confirmé que l’HI induit une majoration de la taille d’infarctus suite à un évènement ischémique aigue et aggrave le remodelage cardiaque et la dysfonction contractile dans un modèle de cardiopathie ischémique chronique chez le rat. Nous avons également mis en évidence que l’HI induisait dans ce contexte une hyperactivation sympathique persistante, un stress du RE proapoptotique et l’activation du facteur de transcription HIF-1 contribuant à l’augmentation de la vulnérabilité du cœur à l’infarctus et l’aggravation post-IM des complications cardiaques au long-terme. Ces différents facteurs pourraient représenter des biomarqueurs intéressants pour prédire le risque CV chez les patients apnéiques sévères et pourraient être considérés comme des pistes thérapeutiques potentielles pour améliorer la prise en charge des patients SAOS à haut risque CV. / Obstructive sleep apnea syndrome (OSA) is a common disease that affects 6-13% of the middle-aged population. Epidemiological and clinical data support the notion that OSA has a role in the initiation or progression of several cardiovascular (CV) diseases, including myocardial infarction (MI). Indeed, patients hospitalized with acute MI present high prevalence for OSA. Furthermore, OSA is known to major infarct size in patients that persists over time and aggravates long-term adverse events post-MI, as reinfarction, heart failure (HF) and death. OSA is characterized by intermittent hypoxia (IH) which results in desaturation-reoxygenation sequences and appears to be the major consequence of OSA in term of cardiovascular alterations associated with apneas. However, the mechanisms remain unclear. Therefore, the understanding of pathophysiologic mechanisms involved in cardiac disorders is a research priority for OSA in order to develop new therapeutic targets and improve the management of CV risk in apneic patients. There are growing evidences suggesting a major role of endoplasmic reticulum (ER) stress and HIF-1 activation in the vulnerability to acute ischemic events and in long-term adverse complications associated with prolonged MI. Furthermore, the progression of ischemic cardiomyopathy following MI is also associated with activation of the sympathetic nervous system which substantially contributes to cardiac alterations. Furthermore, these are three mechanisms known to be activated with IH. This project aimed 1) to assess the IH-induced acute and chronic cardiac alterations following MI, 2) to study the implication of cellular mechanisms involved in the adverse ischemic events related to OSA.We have shown that IH increases infarct size following acute MI and aggravates cardiac remodeling and contractile dysfunction in a rat model of chronic ischemic cardiomyopathy. In these contexts, IH is associated with a sympathetic over activity, a proapoptotic ER stress and the activation of HIF-1, which substantially contribute to increased heart vulnerability to infarction and worsening of long-term heart complications post-MI. These different factors may represent interesting biomarkers for predicting CV risk in severe apneic patients and may be considered as potential therapeutic targets to improve the management of OSA patients with high CV risks.

Made available in DSpace on 2016-06-02T19:46:02Z (GMT). No. of bitstreams: 1 2180.pdf: 923936 bytes, checksum: 8c877a2bc70bc866deb865883e5ade93 (MD5) Previous issue date: 2008-02-25 / Universidade Federal de Minas Gerais / The present proposal is based on the assumption that verbal responding is operant behavior established and maintained by reinforcement contingencies, and that this behavior can be analysed as a dependent variable. Recent research about say-do correspondence have used the educational context to investigate conditions able to guarantee corresponding reports of errors and correct responses about academical activities. The present study investigated the influence of a history of school failure and task difficulty on self-report of two groups of children about their reading performance, as well the effects of reinforcement schedules on the establishment and maintenance of accurate reports. Four children with history of school failure and four children without such history, all of them attending Fundamental Education, participated. Doing consisted in reading aloud a written word presented on the computer s screen and Saying in reporting if the reading was correct or not. The experiment began with a General Pretest that evaluated the participants reading repertoire, followed by baseline sessions that verified frequency of corresponding reports as a function of increasing probability of errors in a session (10, 25, 50 e 70%). On the next phase, correspondence training sessions, in which corresponding reports were reinforced continuously and later intermittently (variable ratio), were conducted. Finally, a baseline return was conducted to evaluate if the previously trained conditions were sufficient to promote accurate self-report maintenance. Points exchangeable for gifts were used as consequences. There were no pronounced differences on the average of corresponding reports of errors or correct responses between the two groups during the first baseline, along the different error probabilities programmed (except during 50% error probability). On the other hand, most non-corresponding reports of error occurred when the programmed error probability was about 50% for the children with history of school failure and about 25% for those without such history. The correspondence training was effective to produce corresponding reports for all participants. The high correspondence level was maintained during the intermittent reinforcement phase as well during the subsequent extinction condition. Error frequency seemed to be a relevant variable for self-report accuracy for all children on this study, independently of the presence or absence of history of school failure and of the increasing levels of task difficulty. The intermittent reinforcement training was effective to maintain corresponding reports of errors and correct responses during subsequent conditions in which no consequences for responding were programmed. / A presente proposta apóia-se na suposição de que o responder verbal é um comportamento operante estabelecido e mantido por contingências de reforçamento, podendo ser analisado como variável dependente. Pesquisas recentes sobre correspondência fazer-dizer têm utilizado o contexto educacional para investigar condições capazes de garantir relatos correspondentes de acerto e erro em atividades acadêmicas. O presente estudo investigou a influência da história de fracasso escolar e da dificuldade da atividade sobre o auto-relato de dois grupos de crianças sobre seus desempenhos em leitura, bem como o efeito de esquemas de reforço sobre o estabelecimento e a manutenção de relatos acurados. Participaram deste estudo quatro crianças com história de fracasso escolar e quatro crianças sem história de fracasso escolar, todas do Ensino Fundamental. Fazer consistiu em ler em voz alta uma palavra escrita no computador e Dizer em relatar se a leitura foi ou não correta. O experimento foi iniciado com um pré-teste geral que avaliou o repertório de leitura dos participantes, seguido por sessões de linha de base que verificaram a freqüência dos relatos correspondentes em função da probabilidade de erro crescente ao longo das sessões (10, 25, 50 e 70%). Na fase seguinte, foram realizadas sessões de treino de correspondência, em que os relatos correspondentes foram reforçados, primeiramente de forma contínua e, num segundo momento, de forma intermitente (razão variável). Por fim, houve o retorno à linha de base, que avaliou se as condições anteriores de treino foram suficientes para promover a manutenção de auto-relatos acurados. Como conseqüências foram utilizados pontos trocáveis por brindes. Não houve diferenças acentuadas entre as médias de relatos correspondentes de acertos e erros para os dois grupos, durante a linha de base inicial, nas diferentes faixas de probabilidade de erro (apenas na faixa de 50%). No entanto, a maior freqüência de relatos não-correspondentes de erro ocorreu quando a probabilidade de erro programada era de 50% para as crianças com fracasso escolar e de 25% para as crianças sem fracasso escolar. O treino de correspondência produziu relatos correspondentes para todos os participantes. O nível elevado de correspondência foi mantido tanto na fase de reforçamento intermitente quanto na condição subseqüente de extinção. O erro pareceu ser variável relevante para a acurácia do relato de leitura de todas as crianças, independentemente da presença ou ausência de histórico de fracasso escolar e do aumento da dificuldade da tarefa. O treino com reforçamento intermitente mostrou-se eficaz na manutenção de relatos correspondentes de acertos e erros em situações subsequentes, em que nenhuma conseqüência foi programada para o responder.

Made available in DSpace on 2016-12-06T17:07:10Z (GMT). No. of bitstreams: 1 DISSERTACAO_CARMINATTI.pdf: 1003035 bytes, checksum: 8564e54c742b47d3e336ac8bdd87e443 (MD5) Previous issue date: 2006-12-15 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Anaerobic threshold (LAn) obtained during an incremental test with continuous effort, presumably indicate the workload corresponding to maximal lactate steady state (MSSL). Based on this present theoretical model, several non-invasive LAn derived from TCAR have been used as predictors of MSSL. Among them, the HR thresholds identified by visual inspection (PDv) and by the mathematical method (Dmáx), predicted Dmáx (Dmáxpred) and threshold velocity of 4 mmol·l-1 predicted (V4pred). The purpose of the present investigation was to ascertain the validity of these thresholds as predictors of MSSL in Futsal. Eight Futsal players (21.3 ± 3.1 years; 177.4 ± 7.7 cm; 79.4 ± 21.2 kg; 13.2 ± 5,7 % of fat) were submitted to the following field tests: 1) Incremental test of intermittent run (TCAR) performed in the shuttle run system, constituted of repetitions of 12 second runs interpolated by 6 seconds of walk, with initial speed of 9 Km·h-1 and increased of 0.6 Km·h-1 every 90 seconds until voluntary exhaustion. Variables identified in the TCAR: velocity (V) and HR of several predictors LAn; 2) Constant workload test, with duration of 32 minutes divided in 4 series of 8 minutes of intermittent run (same system applied in TCAR), with passive interval of 1 minute to collect 25 &#956;L of blood samples and measure the HR. MSSL was defined as being the highest speed where the lactate steady-state occurred (increase not superior to 1.2 mmol·l-1 between the 8th and 32nd minute). The first constant workload test of 32 minutes was conducted with 100% of the speed of Dmáx (VDmáx) and following constant load tests were performed and speed increased 0.6 km·h-1 after each constant load test until the MSSL was attained. Variables identified in the test: velocity and HR corresponding to MSSL (VMSSL and HRMSSL). The results obtained to velocity and HR of predictor s LAn were: VPDv (13.0 ± 1.5 km·h-1), VDmáx (12.2 ± 1.4 km·h-1), VDmáxpred (12.4 ± 1.2 km·h-1), V4pred (13.3 ± 0.8 km·h-1) and HRPDv (186 ± 11 bpm), HRDmáx (178 ± 10 bpm), HRDmáxpred (183 ± 8 bpm), when compared to VMSSL (12.5 ± 1.6 km·h-1) and HRMSSL (182 ± 4 bpm) respectively, didn t show differences (p>0.05). The correlations found were significant, specially VDmáx (r = 0.98) and HRDmáx (r = 0.88), with exceptions for HRDmáxpred (r = 0.53) and V4pred (r = 0.70), both not significant. The values found in the concentration of lactate in MSSL were 4.2 ± 1.8 mmol·l-1 (1.4 to 6.7). Therefore, the conclusion is that LAn derived from TCAR are valid as predictors of MSSL in Futsal players and that the physiological responses verified in this intermittent running were similar to the present theoretical model, suggesting a generalizable model. / O Limiar anaeróbio (Lan) obtido durante um teste incremental em esforço contínuo, presumivelmente indica a carga de trabalho correspondente ao máximo steady-state de lactato (MSSL). Com base nesse modelo teórico vigente, diversos LAn não-invasivos derivados do TCAR têm sido utilizados como preditores do MSSL. Entre eles, os limiares de freqüência cardíaca identificados por inspeção visual (PDv) e pelo método matemático (Dmáx), o Dmáx predito (Dmáxpred) e a velocidade de limiar de 4 mmol·l-1 predita (V4pred). O objetivo da presente investigação foi verificar a validade desses Lan como preditores do MSSL na modalidade de Futsal. Oito jogadores de Futsal (21,3 ± 3,1 anos; 177,4 ± 7,7 cm; 79,4 ± 21,2 kg; 13,2 ± 5,7 %gordura) foram submetidos aos seguintes testes de campo: 1) Teste incremental de corrida intermitente (TCAR) realizado em sistema de "ida-e-volta", constituído de repetições de 12 segundos de corrida intercaladas por 6 segundos de caminhada, com velocidade inicial de 9 km·h-1 e incrementos de 0,6 km·h-1 a cada 90 segundos até a exaustão voluntária. Variáveis identificadas no TCAR: velocidade (V) e freqüência cardíaca (FC) dos diversos Lan preditores; 2) Teste de carga constante (TCC) com duração de 32 minutos divididos em 4 séries de 8 minutos de corrida intermitente (mesmo sistema aplicado no TCAR), com intervalo passivo de 1 minuto para coletar amostras de 25 µL de sangue e mensurar a FC. O MSSL foi definido como sendo a maior velocidade onde ocorreu steady-state de lactato (aumento não superior a 1,2 mmol·l-1 entre o 8º e 32º minuto). O primeiro TCC foi realizado com 100% da velocidade do Dmáx (VDmáx) e subsequentes TCC foram aplicados e a velocidade incrementada em 0,6 km·h-1 após cada TCC até que o MSSL foi verificado. Variáveis identificadas no TCC: V e FC correspondentes ao MSSL (VMSSL e FCMSSL). Os resultados obtidos para V e FC dos Lan preditores foram: VPDv (13,0 ± 1,5 km·h-1), VDmáx (12,2 ± 1,4 km·h-1), VDmáxpred (12,4 ± 1,2 km·h-1), V4pred (13,3 ± 0,8 km·h-1) e FCPDv (186 ± 11 bpm), FCDmáx (178 ± 10 bpm), FCDmáxpred (183 ± 8 bpm), respectivamente. Quando foram comparadas com a VMSSL (12,5 ± 1,6 km·h-1) e FCMSSL (182 ± 4 bpm), não apresentaram diferenças (p>0,05). As correlações encontradas foram significantes, com destaque para a VDmáx (r = 0,98) e FCDmáx (r = 0,88), com exceções para FCDmáxpred (r = 0,53) e V4pred (r = 0,70), ambas não significantes. Os valores encontrados de concentração de lactato no MSSL foram 4,2 ± 1,8 mmol·l-1 (1,4 a 6,7). Assim, concluiu-se que os Lan derivados do TCAR são válidos como preditores do MSSL em jogadores de Futsal e que, as respostas fisiológicas verificadas nesse sistema de corrida intermitente foram similares ao modelo teórico vigente, sugerindo um modelo generalizável.

Made available in DSpace on 2016-12-06T17:07:18Z (GMT). No. of bitstreams: 1 Ana P Damiano.pdf: 1573878 bytes, checksum: c1d4586f2c9d815e5179472918435bc3 (MD5) Previous issue date: 2008-09-05 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Intermittent claudication (IC) is the main symptom of peripheral arterial occlusive disease (PAOD) and it can severely affect the walking capacity. This study aimed to investigate the effects of a short-course physical exercise program on intermittent claudication of PAOD patients. Twelve out of the 34 recruited subjects were excluded for several reasons. Twenty-two subjects (14 males, mean age 64.4 ± 10.4 years, ankle-brachial index &#8804; 0.8) with varied clinical characteristics were included, and all have participated in Programa de Reabilitação de Doenças Vasculares Periféricas do Núcleo de Cardiologia e Medicina do Exercício (NCME) of the CEFID/UDESC. The physical performance was objectively assessed by means of a 6-minute walk test and subjectively assessed by means of the walking impairment questionnaire. The primary walking test was carried out in order to assess the initial and absolute claudication distances, and lasted up to 15 minutes. The final test lasted up to 30 minutes, if necessary. The results showed that 3 out of the 22 participants had no claudication, being able to walk up to one hour without pain. The mean improvement of the initial claudication distance for the 19 remaining participants was 74.15% (67.6 ± 61.4m, p<0.05). Eleven patients (50%) did not report absolute claudication pain during the primary test; 3 patients, with prior absolute claudication pain, completed the final walking test without reporting pain, and the 8 remaining patients, who still reported absolute claudication pain, had a mean improvement of 48.61% (84.3 ± 58.8m, p<0.05) in walking distance. Regarding the distance walked in 6 minutes, the mean improvement of the 22 patients was 17% (41.1 ± 62.5, p<0.05). It was also possible to notice mean improvement (n = 22) of 14.30% (p<0.05) in walking capacity impairment; 17.56% (p<0.05) in walking distance; 4.59% (p=0.258) in walking speed and 5.49% (p=0.468) in stair climbing. In conclusion, a short-course physical exercise program is effective in PAOD and IC patients. Throughout the walking test, the initial and absolute claudication distances and the distance walked in 6 minutes were significantly improved. The walking impairment questionnaire showed considerable improvements related to walking impairment and walking distance, however, concerning walking speed and stair climbing, the improvements were not statistically significant. / A claudicação intermitente (CI) é o principal sintoma da doença arterial obstrutiva periférica (DAOP) e pode comprometer severamente o desempenho de caminhada. O objetivo do estudo foi investigar os efeitos de um programa de exercício físico a curto prazo na claudicação intermitente de pacientes com DAOP. Dos 34 indivíduos selecionados, 12 foram excluídos por diversos motivos. Os 22 incluídos (14 do gênero masculino, média de idade 64,4 + 10,4 anos, índice tornozelo braquial < 0,8), todos participantes do Programa de Reabilitação de Doenças Vasculares Periféricas do Núcleo de Cardiologia e Medicina do Exercício (NCME) do CEFID/UDESC, apresentavam características clínicas heterogêneas. O desempenho físico foi avaliado objetivamente por meio do teste de caminhada de 6 minutos e subjetivamente pelo questionário de dificuldade para caminhar. O teste inicial de caminhada, destinado à avaliação das distâncias de claudicação inicial e absoluta, foi prolongado até 15 minutos e o final, quando necessário, até 30 minutos. Os resultados demonstraram que, dos 22 participantes do estudo, 3 deixaram de sentir a claudicação, caminhando até uma hora no programa de exercícios sem referir dor. Nos 19 pacientes restantes, a melhora média da distância de claudicação inicial foi de 74,15% (67,6 ± 61,4m, p<0,05). Dos 22 pacientes incluídos no estudo, 11 (50%) não apresentaram dor da claudicação absoluta no teste inicial; 3 pacientes, antes com dor da claudicação absoluta, completaram o teste de caminhada final sem essa manifestação e nos restantes (8 pacientes), que ainda apresentavam dor da claudicação absoluta, foi observada melhora média na distância caminhada de 48,61% (84,3 ± 58,8m, p<0,05). Quanto à distância percorrida em 6 minutos, a melhora média dos 22 pacientes foi de 17% (41,1 ± 62,5, p<0,05). Foi ainda constatado melhora média (n = 22) de 14,30% (p<0,05) na dificuldade para caminhar; 17,56% (p<0,05) na distância de caminhada; 4,59% (p = 0,258) na velocidade de caminhada e 5,49% (p = 0,468) na subida de degraus. Conclui-se que um programa de exercício físico a curto prazo é eficiente no tratamento de pacientes com DAOP e CI. Foi possível observar, por meio do teste de caminhada, melhora significativa na distância para claudicação inicial e absoluta e na distância percorrida em 6 minutos. A aplicação do questionário de dificuldade para caminhar demonstrou melhoras significativas relacionadas à dificuldade para caminhar e à distância de caminhada, sendo, entretanto, as melhoras relacionadas à velocidade de caminhada e subida de degraus consideradas estatisticamente não significativas.