Les changements climatiques sont susceptibles d’affecter la croissance, le développement et la régénération des pessières noires de la forêt boréale. Les échecs de régénération dans les pessières à mousses (PM) de l’ouest du Québec causent des trouées dans la mosaïque forestière dense et augmentent la proportion de pessières à lichens (PL) dans le paysage. Les objectifs de l’étude sont de déterminer si les caractéristiques contrastantes des PM et des PL engendrent différents taux de photosynthèse maximale (Amax) chez les épinettes noires sur un gradient latitudinal ou saisonnier. Ensuite, l’étude tentera de déterminer si le Amax des individus reflète leurs capacités physiologiques par leur taux de carboxylation maximal (Vcmax) et de transport des électrons maximal (Jmax) extraits de courbes de réponse au CO2. Les taux de Vcmax et Jmax sont différents entre les PM et les PL car l’acquisition de ces nutriments semble différente. La latitude influence les valeurs de Vcmax et Jmax, mais l’effet serait causé par les caractéristiques floristiques et la composition du sol des placettes plutôt que par la latitude. Les capacités physiologiques ne se reflètent pas dans les valeurs de Amax, autant pour le type de peuplement que la latitude, car Amax serait limité par la concentration en CO2 qui ne permet pas la saturation de l’enzyme rubisco. Malgré l’absence de différence entre le Amax des PM et des PL, l’augmentation de la concentration en CO2 et de la température risque de créer un écart de Amax entre les types de peuplement, considérant leurs capacités physiologiques différentes. / Climate change is likely to affect the growth, development and regeneration of black spruce stands across the boreal forest. Regeneration failures cause gaps in the dense black spruce-feathermoss (BSFM) mosaic increasing the landscape proportion of open lichen-woodland (LW). The aims of the study are to determine whether the contrasting characteristics of BSFM and LW induce different light-saturated maximum photosynthesis (Amax) in black spruce trees across a latitudinal or seasonal gradient. Then the study will attempt to determine if Amax is likely to reflect their physiological capacities based on their maximum carboxylation rate (Vcmax) and maximum electron transport rate (Jmax) derived from CO2 response curves. Vcmax and Jmax are different between BSFM and LW mainly because nutrient acquisition seems different between stand types. Latitude affects values of Vcmax and Jmax, but the effect could be explained by soil and vegetation composition between experimental plots rather than by latitude. Physiological capacities do not match Amax values for stand type and latitude because Amax would be limited by CO2 concentration which does not allow saturation of rubisco. Despite the lack of difference between the Amax of BSFM and LW stands, future increase in CO2 concentration and temperature could induce a gap between their respective photosynthesis rates because of their different physiological capacities.

Syfte och frågeställningar Syftet med denna studie var att undersöka utveckling av styrka och aerob förmåga vid kombinationsträning med olika intensitet och volym i den aeroba träningen. Studiens frågeställningar var: (1) Utvecklas maximal styrka olika då styrketräning kombineras med antingen högintensiv aerob träning i intervallform eller aerob medelintensiv kontinuerlig träning? (2) Vilket av dessa två kombinationsprogram är effektivast för att öka maximal syreupptagningsförmåga (VO2max), laktattröskeln, maximalt blodlaktat och tid till utmattning?   Metod En kvantitativ träningsstudie genomfördes med 18 manliga försökspersoner (fp) som under en sex veckors period fick bedriva styrketräning och aerob träning kombinerat i ett och samma träningsprogram. Fp delades in i två olika grupper om vardera nio personer där den aeroba träningen skiljde grupperna åt. Under den sex veckor långa träningsperioden fick båda grupperna utföra ett vetenskapligt förankrat styrketräningsprogram med knäböj som övning tre gånger i veckan i syfte att utveckla maximal styrka. Direkt efter avslutat styrkepass fick ena gruppen (försöksgruppen) dessutom utföra ett högintensivt aerobt träningspass i intervallform på ergometercykel med liten volym (4-20 min), medan den andra gruppen (kontrollgruppen) istället fick utföra ett aerobt medelintensivt kontinuerligt träningspass med större volym (40-80 min). Såväl före som efter den sex veckor långa träningsperioden fick samtliga fp genomföra tester med identiskt testförfarande. Härmed kunde skillnader i utveckling av maximal styrka i 1RM i knäböj, VO2max, förmåga att bilda och hantera laktat samt tid till utmattning mellan de två grupperna undersökas.   Resultat Resultatet visade att både kontroll- och försöksgrupp ökade signifikant i styrkeövningen 1RM i knäböj. Vidare ökade båda grupperna signifikant i VO2max, tröskelbelastning samt tid till utmattning vid ergometercykling. Försöksgruppen ökade signifikant mer i blodlaktatnivå vid tröskelbelastningen än kontrollgruppen. Dessutom fanns en statistisk tendens som visade att försöksgruppen ökade sin förmåga att utveckla maximalt blodlaktat mer än kontrollgruppen. Utöver detta förekom ingen signifikant skillnad i utveckling grupperna emellan för någon av övriga uppmätta variabler. Dock kunde en statistisk indikation noteras vid summering av samtliga prestationspåverkande variabler som mättes i studien, vilken talade för att försöksgruppens träning hade mer positiva effekter ur ett prestationsperspektiv jämfört med kontrollgruppens träning.   Slutsats Maximal styrka utvecklas likvärdigt oavsett om styrketräning kombineras med högintensiv aerob träning i intervallform eller aerob medelintensiv kontinuerlig träning. Högintensiv aerob träning i intervallform är dock väldigt effektiv ur ett prestationsperspektiv då den utvecklar en mängd fysiska delkapaciteter med väldigt liten tidsåtgång. / <p>Uppsatsen tilldelades stipendiemedel ur Överste och Fru Adolf Johnssons fond för VT 2015.</p>

Introduction Performance in cross-country skiing is influenced by the skier’s ability to continuously produce propelling forces and force magnitude in relation to the net external forces. A surrogate indicator of the “power supply” in cross-country skiing would be a physiological variable that reflects an important performance-related capability, whereas the body mass itself is an indicator of the “power demand” experienced by the skier. To adequately evaluate an elite skier’s performance capability, it is essential to establish the optimal ratio between the physiological variable and body mass. The overall aim of this doctoral thesis was to investigate the importance of body-mass exponent optimization for the evaluation of performance capability in cross-country skiing. Methods In total, 83 elite cross-country skiers (56 men and 27 women) volunteered to participate in the four studies. The physiological variables of maximal oxygen uptake (V̇O2max) and oxygen uptake corresponding to a blood-lactate concentration of 4 mmol∙l-1 (V̇O2obla) were determined while treadmill roller skiing using the diagonal-stride technique; mean oxygen uptake (V̇O2dp) and upper-body power output (Ẇ) were determined during double-poling tests using a ski-ergometer. Competitive performance data for elite male skiers were collected from two 15-km classical-technique skiing competitions and a 1.25-km sprint prologue; additionally, a 2-km double-poling roller-skiing time trial using the double-poling technique was used as an indicator of upper-body performance capability among elite male and female junior skiers. Power-function modelling was used to explain the race and time-trial speeds based on the physiological variables and body mass. Results The optimal V̇O2max-to-mass ratios to explain 15-km race speed were V̇O2max divided by body mass raised to the 0.48 and 0.53 power, and these models explained 68% and 69% of the variance in mean skiing speed, respectively; moreover, the 95% confidence intervals (CI) for the body-mass exponents did not include either 0 or 1. For the modelling of race speed in the sprint prologue, body mass failed to contribute to the models based on V̇O2max, V̇O2obla, and V̇O2dp. The upper-body power output-to-body mass ratio that optimally explained time-trial speed was Ẇ ∙ m-0.57 and the model explained 63% of the variance in speed. Conclusions The results in this thesis suggest that V̇O2max divided by the square root of body mass should be used as an indicator of performance in 15-km classical-technique races among elite male skiers rather than the absolute or simple ratio-standard scaled expression. To optimally explain an elite male skier’s performance capability in sprint prologues, power-function models based on oxygen-uptake variables expressed absolutely are recommended. Moreover, to evaluate elite junior skiers’ performance capabilities in 2-km double-poling roller-skiing time trials, it is recommended that Ẇ divided by the square root of body mass should be used rather than absolute or simple ratio-standard scaled expression of power output. / <p>Incorrect ISBN in printed thesis: 973-91-7601-270-3</p>

本文針對2-連通的最大外平面圖，討論其有界容忍表示法，且找到禁止子圖S3。我們更進一步證明：如果一個2-連通的最大外平面圖恰有兩個點的度為2時，則此圖為區間圖。 / We prove that a 2-connected maximal outerplanar graph G is a bounded tolerance graph if and only if there is no induced subgraph S3 of G and G has no induced subgraph S3 if and only if G is an interval graph.

Cerebral autoregulation describes the clinically observed phenomenon that cerebral blood flow remains relatively constant in healthy human subjects despite large systemic changes in blood pressure, dissolved blood gas concentrations, heart rate and other systemic variables. Cerebral autoregulation is known to be impaired post ischaemic stroke, after severe head injury, in patients suffering from autonomic dysfunction and under the action of various drugs. Cerebral auto-regulation is a dynamic, multivariate phenomenon. Sensitive techniques are required to monitor cerebral auto-regulation in a clinical setting. This thesis presents 4 related signal processing studies of cerebral autoregulation. The first study shows how consideration of changes in blood gas concentrations simultaneously with changes in blood pressure can improve the accuracy of an existing frequency domain technique for monitoring cerebral autoregulation from spontaneous fluctuations in blood pressure and a transcranial doppler measure of cerebral blood flow velocity. The second study shows how the continuous wavelet transform can be used to investigate coupling between blood pressure and near infrared spectroscopy measures of cerebral haemodynamics in patients with autonomic failure. This introduces time information into the frequency based assessment, however neglects the contribution of blood gas concentrations. The third study shows how this limitation can be resolved by introducing a new time-varying multivariate system identification algorithm based around the dual tree undecimated wavelet transform. All frequency and time-frequency domain methods of monitoring cerebral autoregulation assume linear coupling between the variables under consideration. The fourth study therefore considers nonlinear techniques of monitoring cerebral autoregulation, and illustrates some of the difficulties inherent in this form of analysis. The general approach taken in this thesis is to formulate a simple system model; usually in the form of an ODE or a stochastic process. The form of the model is adapted to encapsulate a hypothesis about features of cerebral autoregulation, particularly those features that may be difficult to recover using existing methods of analysis. The performance of the proposed method of analysis is then evaluated under these conditions. After this testing, the techniques are then applied to data provided by the Laboratory of Human Cerebrovascular Physiology in Alberta, Canada, and the National Hospital for Neurology and Neurosurgery in London, UK.

Background: The purpose of this study was the comparison of the calculated (MLSSC) and experimental power (MLSSE) in maximal lactate steady-state (MLSS) during cycling. Methods: 13 male subjects (24.2 ± 4.76 years, 72.9 ± 6.9 kg, 178.5 ± 5.9 cm, V_O2max: 60.4 ± 8.6 ml min−1 kg−1, V_ Lamax: 0.9 ± 0.19 mmol l-1 s-1) performed a ramp-test for determining the V_O2max and a 15 s sprint-test for measuring the maximal glycolytic rate (V_ Lamax). All tests were performed on a Lode-Cycle-Ergometer. V_O2max and V_ Lamax were used to calculate MLSSC. For the determination of MLSSE several 30 min constant load tests were performed. MLSSE was defined as the highest workload that can be maintained without an increase of blood-lactate-concentration (BLC) of more than 0.05 mmol l−1 min−1 during the last 20 min. Power in following constant-load test was set higher or lower depending on BLC. Results: MLSSE and MLSSC were measured respectively at 217 ± 51 W and 229 ± 47 W, while mean difference was −12 ± 20 W. Orthogonal regression was calculated with r = 0.92 (p < 0.001). Conclusions: The difference of 12 W can be explained by the biological variability of V_O2max and V_ Lamax. The knowledge of both parameters, as well as their individual influence on MLSS, could be important for establishing training recommendations, which could lead to either an improvement in V_O2max or V_ Lamax by performing high intensity or low intensity exercise training, respectively. Furthermore the validity of V_ Lamax -test should be focused in further studies.

The aim oftbe work was to get concrete and objective view of the movement of defined parts in lumbar spine during postural task. The other goal was to measure respiratory muscle strenght a find if there was a connection between measured parameters. 35 subjects with chronic low back pain and 25 asymptomatic subjects underwent dynamic MRl examination and measurement of maximal mouth pressures. This study showed lower valu es of Pimax and displacement of vertebra Ll in group of patients. AIso showed correlation between Pimax and Ll dispalcement, sacrum displacement and the sacral slope difference during postural task in group of patients. No significant correlations in control group were found. Powered by TCPDF (www.tcpdf.org)

Theoretical part of this thesis is focused on a heart rate, especially its parameters, measurement methods and regulation. Moreover describes maximal heart rate issue. Practical part was performed as an experimental measurement of maximal heart rate level of 40 healthy adult probands (20 men and 20 women) between the ages of twenty and forty. Maximal heart rate was measured by telemetry meter FT4 Polar ® in 3 types of exercise tests - running, ergometer cycling and swimming. Results were statistically processed. Study confirmed significant differences in maximal heart rate during running, ergometer cycling and swimming. Highest heart rate was reached while running for 95% of measured volunteers and the lowest heart rate was reached during swimming for 98% of probands. The objective of this thesis was a comparison of reached heart rates during different exercise tests and highlight the evidence of dissimilar maximal heart rate during different exercises. Powered by TCPDF (www.tcpdf.org)

The presented thesis is focused on the influence of postural stability changes on respiratory muscle strength. The aim of this thesis was to determinate whether the respiratory muscle strength will change during the increased demands on postural stability, and if so, then how exactly. The theoretical part summarized the findings about the diaphragm and its postural stabilizing function, about the connection between breathing and postural control as well as about the influence of body position on respiratory muscle strength. In the practical part of the thesis, the values of the maximal respiratory mouth pressures were measured (PI max and PE max) on 21 healthy subjects ranging from 20 to 26 years of age using the spirometer in three postural situations - standing, standing on the balance surface and standing on the balance surface with no visual control. Throughout the whole group, there were no significant statistical differences ( p ≥ 0,05 ) in the outcome values of the measured postural situations. Two trends were observed in the changes of values of PI max and PE max. During the increased demands for postural stability the value of PI max was higher for 29% and lower for 71% of the measured individuals. The value of PE max was higher for 33% and lower for 67% of the measured individuals. This...

The purpose of this thesis is to define norms for inspiratory (Pimax) and expiratory (Pemax) pressures and mouth occlusion pressure (P0.1) in healthy white population of the 16-17 age group in the Czech Republic, specifically the capital city of Prague and its close vicinity. Furthermore, this work aspires to ascertain whether there is a correlation between the respiratory pressures, P0.1 and selected anthropometric and pulmonary values. In order to define the norms, 79 children were tested, including 41 boys and 38 girls 16 to 17 years old. After establishing the subjects' case histories, anthropometric, spirometric inspiratory, expiratory and forced vital capacity measurements were made. The study defined the norms of respiratory pressures and P0.1 in 16 to 17-year-old boys and girls, thus achieving its main goal. Furthermore, a difference was found between the average measured Pimax and Pemax values for boys and girls, with the boys showing higher values comparing with the girls. The study did not ascertain a correlation between respiratory pressures, P0.1 and selected anthropometric values (age, height, weight, BMI, BSA). No correlation was found between respiratory pressures and static pulmonary volumes. Powered by TCPDF (www.tcpdf.org)