Muscle fatigue is ubiquitous in every day life.Muscle fatigue might be considered as an altered state of motor behaviour, which impairs motor performance. By contrast, muscle fatigue could also be considered a positive phenomenon, which protects muscle tissue from damage that might be incurred to it by overuse. The principal aim of the thesis was to explore some of the mechanisms of muscle fatigue at the spinal level in animal models.The activation of multiple motor units of a single calf muscle may influence contractile properties of its neighbouring, otherwise inactive units, providing evidence for spatial spreading of fatigue between different muscle parts. The release of metabolites, their action on inactive muscle units and the effects of local hypoxia are the most likely causes. Fatigue-induced metabolite shift in the interstitium provokes excitation and/or sensitisation of high-threshold afferent fibers, with complex effects on the spinal premotoneuronal network involved in the modulation of motoneuronal output. This was examined by studing the intrasegmental lamellar distribution of the lumbar spinal interneurons following fatiguing contractions of the triceps surae muscle. Furthermore, fatigue of calf muscles enhanced the activity of fusimotor neurons to these muscles irrespective of the regime of muscle activity (isometric vs. lengthening) in conditions that simulate locomotion. Altered fusimotor activity, through increased or maintained muscle spindle afferent responsiveness may be advantageous, providing support to the skeletomotor activity and enhanced information about muscle periphery to higher nervous centres. The particular effects of interneuronal network at motor input (presynaptic inhibition system) and output (recurrent inhibition system) stages were then addressed. Fatigue of triceps surae muscle induced a suppression of the monosynaptic reflex. The intensity of presynaptic inhibition increased, while the intensity of recurrent inhibition decreased. Post fatigue-evoked changes in monosynaptic reflexes and presynaptic inhibition indicate the possibility that high-threshold afferents inhibit group Ia terminals pre-synaptically, which would allow fatigue-induced signals from the muscle to reduce the relevance of proprioceptive feedback. Besides intrasegmental, intersegmental spreading of nociceptive signals was explored. Activation of sensory afferents from dorsal neck muscles by capsaicin induces powerful activation of interneurons located in the cervical spinal cord, as well as a widespread activation of cells in lumbar spinal cord segments. The results confirm the pivotal role of small diameter muscle afferents in the orchestration of segmental responses to fatigue and show complex interactions that may lead to limited accuracy of motor output. They also depict processes that may be related to, and even become precursors of chronic muscle pain.

Background: This article presents prospective lower bound estimations of findings on prevalence, incidence, clinical correlates, severity markers, co-morbidity and course stability of threshold and subthreshold recurrent brief depressive disorder (RBD) and other mood disorders in a community sample of 3021 adolescents. Method: Data were collected at baseline (age 14–17) and at two follow-up interviews within an observation period of 42 months. Diagnostic assessment was based on the Munich Composite International Diagnostic Interview (M-CIDI). Results: Our data suggest that RBD is a prevalent (2.6%) clinical condition among depressive disorders (21.3%) being at least as prevalent as dysthymia (2.3%) in young adults over lifetime. Furthermore, RBD is associated with significant clinical impairment sharing many features with major depressive disorder (MDD). Suicide attempts were reported in 7.8% of RBD patients, which was similar to MDD (11.9%). However, other features, like gender distribution or co-morbidity patterns, differ essentially from MDD. Furthermore, the lifetime co-occurrence of MDD and RBD or combined depression represents a severe psychiatric condition. Conclusions: This study provides further independent support for RBD as a clinically significant syndrome that could not be significantly explained as a prodrome or residual of major affective disorders.

In Saskatchewan, stroke is the third leading cause of death as well was the major cause of adult disability. Once a person suffers a stroke or transient ischemic attack (TIA), they are at high risk for having a secondary (or recurrent) stroke. Despite this knowledge, secondary stroke prevention is often overlooked in the care of stroke/TIA patients. With the vision of decreasing the incidence and impact of stroke in Saskatchewan, the Saskatchewan Integrated Stroke Strategy (SISS) was recently implemented. The purpose of this study is to begin the development of an evaluation measurement system for the SISS based on the guidelines and measures from the Canadian Stroke Strategy (CSS) specifically pertaining to secondary stroke prevention.<p> This multi-year cross-sectional study is an analysis of de-identified health data derived from linkage of administrative and laboratory data. Select indicators from the CSS Performance Measurement Manual involving medications use for secondary stroke prevention (antihypertensives, antilipidemics, anticoagulants) and intermediate health outcomes (serum LDL cholesterol, INR) are calculated. Regression is used to quantify the association of patient demographic and socioeconomic characteristics and geographic location of care with receipt of guideline-recommended secondary stroke prevention. The target population is Saskatchewan residents who have been hospitalized for a stroke or TIA between April 1, 2001 and March 31, 2008.<p> The results of this study indicated that secondary stroke prevention in Saskatchewan is sub-optimal in the management of hypertension, dyslipidemia, and atrial fibrillation. Although there has been some improvement over the time period, a significant number of patients are not taking the recommended medications at discharge from acute care. Similarly, a considerable number of patients are not receiving the appropriate laboratory tests within the year following their stroke event. Through regression analysis it was revealed that a number of correlates (ie. age, income, on medication before the stroke event) were significantly associated with receiving these specific elements of secondary stroke prevention, suggesting potential differences in provision of care. Finally, regional differences in secondary stroke prevention were found for a number of the outcomes, which may indicate differences in care throughout the province.<p> The findings of this study serve as a baseline for evaluation of the impact of the Saskatchewan Integrated Stroke Strategy in the area of secondary stroke prevention. The results make apparent the fact that secondary stroke prevention in Saskatchewan can be improved, and that there is much opportunity for future research in this area.

ABSTRACT Heaves is triggered by exposure to dust and its components, such as endotoxin, and is characterized by clinical signs such as coughing, decreased exercise tolerance, difficulty breathing and abnormal lung sounds which are due to bronchoconstriction and accumulation of neutrophils in the airways. Pulmonary intravascular macrophages (PIMs) are believed to increase horses sensitivity to endotoxemia-induced lung inflammation. The first objective of this study was to investigate a hitherto unknown role of PIMs in equine heaves. I used mouldy hay (MH) to induce heaves and gadolinium chloride (GC) to deplete PIMs in order to compare responses between non-treated and GC-treated heaves horses. A modified randomized crossover study (2X2 factorial) was conducted in which mares (N=9) were exposed to 4 different treatments: alfalfa cubes (Cb), alfalfa cubes + GC (Cb-GC), mouldy hay (MH) and MH + GC (MH-GC). Each treatment was followed by broncholaveolar lavage (BAL). MH was fed for 7 days to induce heaves followed by Cb for 21 days to achieve remission, whereas the treatments in which heaves was not induced (Cb; Cb-GC), the cubes were fed prior to the BAL and for 14 days after the BAL to allow recovery from the BAL procedure. BAL fluids were processed to investigate total cell, neutrophil and alveolar macrophage concentrations. In addition, TNFá protein levels as well as TNFá, IL-8, and TLR4 mRNA expression in BAL cells were assessed in order to infer on their activation state.<p> Data showed higher concentration of dust (3X), endotoxin (20X), and endotoxin per milligram of dust (7X) in MH compared to the Cb environment. Clinical scores and neutrophil concentrations in BAL were higher when mares received MH compared to MH and GC (MH-GC). Real time reverse transcriptase PCR revealed a significant lower expression of IL-8 and TLR4 mRNA in BAL cells from MH-GC mares compared to MH. TNFá mRNA expression as well as protein concentration were not affected by the different treatments. In vitro secondary LPS challenge significantly increased IL-8 mRNA expression in cells from MH treatment compared to without LPS, but not in the MH-GC treatment. TLR4 expression was not affected by the secondary challenge. Although secondary LPS challenge increased expression of TNFá mRNA and protein, the differences among treatment groups were not meaningful. In conclusion, PIM depletion attenuates clinical scores, migration of inflammatory cells into the alveolar space and expression of pro-inflammatory molecules in BAL cells of heaves horses.<p> The observations on the role of PIMs in heaves in horses prompted me to examine the occurrence of PIMs in human lungs. I found a trend for higher numbers of septal macrophages in autopsied lungs from human patients who died of non-pulmonary pathologies compared to those having either COPD or asthma. If these septal macrophages indeed represent the PIMs, this finding is contrary to existing belief that humans, unlike horses, do not have PIMs.

Although nonlinear model predictive control (NMPC) might be the best choice for a nonlinear plant, it is still not widely used. This is mainly due to the computational burden associated with solving online a set of nonlinear differential equations and a nonlinear dynamic optimization problem in real time. This thesis is concerned with strategies aimed at reducing the computational burden involved in different stages of the NMPC such as optimization problem, state estimation, and nonlinear model identification. A major part of the computational burden comes from function and derivative evaluations required in different parts of the NMPC algorithm. In this work, the problem is tackled using a recently introduced efficient tool, the automatic differentiation (AD). Using the AD tool, a function is evaluated together with all its partial derivative from the code defining the function with machine accuracy. A new NMPC algorithm based on nonlinear least square optimization is proposed. In a first–order method, the sensitivity equations are integrated using a linear formula while the AD tool is applied to get their values accurately. For higher order approximations, more terms of the Taylor expansion are used in the integration for which the AD is effectively used. As a result, the gradient of the cost function against control moves is accurately obtained so that the online nonlinear optimization can be efficiently solved. In many real control cases, the states are not measured and have to be estimated for each instance when a solution of the model equations is needed. A nonlinear extended version of the Kalman filter (EKF) is added to the NMPC algorithm for this purpose. The AD tool is used to calculate the required derivatives in the local linearization step of the filter automatically and accurately. Offset is another problem faced in NMPC. A new nonlinear integration is devised for this case to eliminate the offset from the output response. In this method, an integrated disturbance model is added to the process model input or output to correct the plant/model mismatch. The time response of the controller is also improved as a by–product. The proposed NMPC algorithm has been applied to an evaporation process and a two continuous stirred tank reactor (two–CSTR) process with satisfactory results to cope with large setpoint changes, unmeasured severe disturbances, and process/model mismatches. When the process equations are not known (black–box) or when these are too complicated to be used in the controller, modelling is needed to create an internal model for the controller. In this thesis, a continuous time recurrent neural network (CTRNN) in a state–space form is developed to be used in NMPC context. An efficient training algorithm for the proposed network is developed using AD tool. By automatically generating Taylor coefficients, the algorithm not only solves the differentiation equations of the network but also produces the sensitivity for the training problem. The same approach is also used to solve online the optimization problem of the NMPC. The proposed CTRNN and the predictive controller were tested on an evaporator and two–CSTR case studies. A comparison with other approaches shows that the new algorithm can considerably reduce network training time and improve solution accuracy. For a third case study, the ALSTOM gasifier, a NMPC via linearization algorithm is implemented to control the system. In this work a nonlinear state–space class Wiener model is used to identify the black–box model of the gasifier. A linear model of the plant at zero–load is adopted as a base model for prediction. Then, a feedforward neural network is created as the static gain for a particular output channel, fuel gas pressure, to compensate its strong nonlinear behavior observed in open–loop simulations. By linearizing the neural network at each sampling time, the static nonlinear gain provides certain adaptation to the linear base model. The AD tool is used here to linearize the neural network efficiently. Noticeable performance improvement is observed when compared with pure linear MPC. The controller was able to pass all tests specified in the benchmark problem at all load conditions.

No description available.

The context of this report and the IRIDIA laboratory are described in the preface. Evolutionary Robotics and the box-pushing task are presented in the introduction.The building of a test system supporting Evolutionary Robotics experiments is then detailed. This system is made of a robot simulator and a Genetic Algorithm. It is used to explore the possibility of evolving box-pushing behaviours. The bootstrapping problem is explained, and a novel approach for dealing with it is proposed, with results presented.Finally, ideas for extending this approach are presented in the conclusion.

ABSTRACT Heaves is triggered by exposure to dust and its components, such as endotoxin, and is characterized by clinical signs such as coughing, decreased exercise tolerance, difficulty breathing and abnormal lung sounds which are due to bronchoconstriction and accumulation of neutrophils in the airways. Pulmonary intravascular macrophages (PIMs) are believed to increase horses sensitivity to endotoxemia-induced lung inflammation. The first objective of this study was to investigate a hitherto unknown role of PIMs in equine heaves. I used mouldy hay (MH) to induce heaves and gadolinium chloride (GC) to deplete PIMs in order to compare responses between non-treated and GC-treated heaves horses. A modified randomized crossover study (2X2 factorial) was conducted in which mares (N=9) were exposed to 4 different treatments: alfalfa cubes (Cb), alfalfa cubes + GC (Cb-GC), mouldy hay (MH) and MH + GC (MH-GC). Each treatment was followed by broncholaveolar lavage (BAL). MH was fed for 7 days to induce heaves followed by Cb for 21 days to achieve remission, whereas the treatments in which heaves was not induced (Cb; Cb-GC), the cubes were fed prior to the BAL and for 14 days after the BAL to allow recovery from the BAL procedure. BAL fluids were processed to investigate total cell, neutrophil and alveolar macrophage concentrations. In addition, TNFá protein levels as well as TNFá, IL-8, and TLR4 mRNA expression in BAL cells were assessed in order to infer on their activation state.<p> Data showed higher concentration of dust (3X), endotoxin (20X), and endotoxin per milligram of dust (7X) in MH compared to the Cb environment. Clinical scores and neutrophil concentrations in BAL were higher when mares received MH compared to MH and GC (MH-GC). Real time reverse transcriptase PCR revealed a significant lower expression of IL-8 and TLR4 mRNA in BAL cells from MH-GC mares compared to MH. TNFá mRNA expression as well as protein concentration were not affected by the different treatments. In vitro secondary LPS challenge significantly increased IL-8 mRNA expression in cells from MH treatment compared to without LPS, but not in the MH-GC treatment. TLR4 expression was not affected by the secondary challenge. Although secondary LPS challenge increased expression of TNFá mRNA and protein, the differences among treatment groups were not meaningful. In conclusion, PIM depletion attenuates clinical scores, migration of inflammatory cells into the alveolar space and expression of pro-inflammatory molecules in BAL cells of heaves horses.<p> The observations on the role of PIMs in heaves in horses prompted me to examine the occurrence of PIMs in human lungs. I found a trend for higher numbers of septal macrophages in autopsied lungs from human patients who died of non-pulmonary pathologies compared to those having either COPD or asthma. If these septal macrophages indeed represent the PIMs, this finding is contrary to existing belief that humans, unlike horses, do not have PIMs.

In Saskatchewan, stroke is the third leading cause of death as well was the major cause of adult disability. Once a person suffers a stroke or transient ischemic attack (TIA), they are at high risk for having a secondary (or recurrent) stroke. Despite this knowledge, secondary stroke prevention is often overlooked in the care of stroke/TIA patients. With the vision of decreasing the incidence and impact of stroke in Saskatchewan, the Saskatchewan Integrated Stroke Strategy (SISS) was recently implemented. The purpose of this study is to begin the development of an evaluation measurement system for the SISS based on the guidelines and measures from the Canadian Stroke Strategy (CSS) specifically pertaining to secondary stroke prevention.<p> This multi-year cross-sectional study is an analysis of de-identified health data derived from linkage of administrative and laboratory data. Select indicators from the CSS Performance Measurement Manual involving medications use for secondary stroke prevention (antihypertensives, antilipidemics, anticoagulants) and intermediate health outcomes (serum LDL cholesterol, INR) are calculated. Regression is used to quantify the association of patient demographic and socioeconomic characteristics and geographic location of care with receipt of guideline-recommended secondary stroke prevention. The target population is Saskatchewan residents who have been hospitalized for a stroke or TIA between April 1, 2001 and March 31, 2008.<p> The results of this study indicated that secondary stroke prevention in Saskatchewan is sub-optimal in the management of hypertension, dyslipidemia, and atrial fibrillation. Although there has been some improvement over the time period, a significant number of patients are not taking the recommended medications at discharge from acute care. Similarly, a considerable number of patients are not receiving the appropriate laboratory tests within the year following their stroke event. Through regression analysis it was revealed that a number of correlates (ie. age, income, on medication before the stroke event) were significantly associated with receiving these specific elements of secondary stroke prevention, suggesting potential differences in provision of care. Finally, regional differences in secondary stroke prevention were found for a number of the outcomes, which may indicate differences in care throughout the province.<p> The findings of this study serve as a baseline for evaluation of the impact of the Saskatchewan Integrated Stroke Strategy in the area of secondary stroke prevention. The results make apparent the fact that secondary stroke prevention in Saskatchewan can be improved, and that there is much opportunity for future research in this area.

This research aims at understanding the effects that Ministry of Education implements the Recurrent Education of in-service master programs in every university. Investigate the adult learners from in-service master programs, specially in the learners¡¦ learning motivations, participation barriers and learning satisfactions in order to the reference which carries out the effort as inspecting. The process of this research¡G Firstly, investigate the learning motivations, participation barriers and learning satisfactions of in-service master program students. Secondly, understand the relationships between (1)the demographics and learning motivations¡Bparticipation barriers and learning satisfactions ,and (2) learning motivations¡B participation barriers and learning satisfactions. Finally, suggest some advises forward on the policy for Recurrent Education of in-service master programs. For supporting the above-mentioned purposes, I used questionnaire investigation method to collect the material data. The currently register students are 1278, particularly in 92nd school year, and the effective samples are 337.Describing statistics, exploratory factor analysis, secondary confirmatory factor analysis and path analysis were used to analyze and explain the raw data. Research tells: ¡]1¡^The learning motivations¡Bparticipation barriers and learning satisfactions are related to certain items of demographics. ¡]2¡^The higher learning motivation which in-service master program students have, the more learning satisfaction they get. The participation barrier is higher and the lower learning satisfaction is. The participation barrier can influence the learning satisfaction through the learning motivation, that means the learning motivation is a intervening variable. The research suggests: ¡]1¡^ Set up the scholarship of in-service master programs to keep the fair position of the students. ¡]2¡^ Legislate the paid educational leave. ¡]3¡^ Strengthen the promotion of educational programs for the expansion of adult learners¡¦ participation. ¡]4¡^ Redistribute educational resources . ¡]5¡^ Have the flexible years of studying and set up the transfer systems.