Il est connu que les personnes ayant une hémiparésie à la suite d’un accident vasculaire cérébral (AVC) présentent une mise en charge (MEC) asymétrique lors de la station debout et lors du passage assis à debout (PAD). Par contre, peu d’études ont quantifié l’évolution de la MEC avec la réadaptation ou la précision avec laquelle ces personnes sont capables de la juger. L’objectif principal de ce projet était d’étudier l’évolution de la répartition et la perception de MEC en position debout et lors du PAD chez des personnes hémiparétiques en réadaptation fonctionnelle intensive (RFI). Un objectif secondaire était d’identifier les facteurs qui caractérisent les personnes hémiparétiques les plus asymétriques et les plus atteintes dans leur perception. Cette étude a été menée auprès de seize participants. Les résultats ont démontré qu’une asymétrie de répartition de l’appui en faveur du côté non parétique est présente dès les premiers mois après l’AVC et qu’elle persiste malgré la RFI. Chez les personnes avec une atteinte sévère de la fonction motrice, la MEC était plus symétrique pour le PAD que la station debout. En termes de perception, les personnes hémiparétiques étaient capables d’identifier le côté sur lequel ils mettaient plus d’appui mais ils avaient tendance à surestimer l’appui sur le côté parétique et donc à se juger moins asymétriques qu’ils ne l’étaient en réalité. Très peu de changements ont été observés lorsque les données au congé étaient comparées aux données à l’entrée dans l’étude. En réponse à l’objectif secondaire, la fonction motrice du membre inférieur parétique évaluée par le Chedoke et la différence de force des extenseurs entre les genoux étaient les facteurs les plus déterminants de l’asymétrie et de la perception de MEC. Les résultats obtenus constituent donc une étape supplémentaire vers la compréhension de la répartition asymétrique et les troubles de perception de MEC lors de la station debout et le PAD chez les personnes hémiparétiques. Il serait intéressant dans le futur d’explorer davantage les facteurs susceptibles d’influencer l’asymétrie et la perception de MEC et d’objectiver la relation de cause à effet entre ces deux variables en plus de préciser l’effet réel de l’asymétrie sur la stabilité posturale. / It is well known that people with hemiparesis after stroke have asymmetric weight bearing (WB) when standing and during sit-to-stand (STS). However, few studies have quantified the evolution of WB with rehabilitation or focused on the accuracy with which hemiparetic individuals are able to perceive their WB. The main purpose of this project was to assess the changes, with rehabilitation, in WB distribution and perception of WB during standing position and STS in hemiparetic individuals. A secondary objective was to identify the factors that characterize the most asymmetric hemiparetic individuals and the most affected in their perception. The study was conducted with sixteen participants. The results showed that asymmetric WB is present in the first months after stroke and persists despite rehabilitation. For individuals who had had severe impairment of motor function, WB was more symmetrical during STS than standing. In terms of WB perception, hemiparetic individuals were able to identify the side on which the loading was higher and they generally overestimated the weight under the paretic side. Overall, data at admission and discharge from the study were not different. Furthermore, the motor function of paretic lower limb evaluated by Chedoke and the strength of knee extensors were the most determinant factors of WB and perception. These results can thus be considered as a further step in order to understand the asymmetrical distribution and the impaired perception of WB. It would be interesting in the future to further explore the factors that may influence the perception and asymmetry of WB in order to identify the relationship between these two variables with a specific focus on the impact of WB asymmetry on the patient’s stability in both tasks.

The Tropical savannas of central Brazil (cerrado) and the Everglades wetland (Florida) ecosystems are ideal systems to study landscape spatial mosaics and their interactions. Both ecosystems show a variety of plant physiognomies distributed within small spatial scales and elevation gradients. Such variety of plant physiognomies provide an opportunity to investigate the roles of climate, topography, nutrient availability and water table dynamics as determinants of plant physiognomic distributions, and their role in shaping regional systems. South Florida Wetlands and the tropical savannas of central Brazil are examples of hydrologically-controlled ecosystems. In hydrologically-controlled ecosystems water sources, the availability of nutrients, and the patterns of water movement play important roles in determining vegetation structure and function. The main objective of this study was to understand ecosystem level processes that shape different physiognomies in two hydrologically-controlled ecosystems. I conducted field work at the IBGE ecological reserve, a field experimental station located in Brasilia, Brazil. I also worked at the Everglades National Park in an area located near the south entrance of the Park in Homestead, Florida. I carried out three interconnected studies investigating water and nutrient dynamics: (1) In a Brazilian savanna I manipulated levels of litter input and measured changes to soil properties, organic matter decomposition and tree growth. I found that changes in litter input affect soil physicochemical properties and soil biochemical processes. I also found that litter dynamics influence tree growth through their effects on soil physicochemical properties. (2) I also studied the effect of water table depth and its temporal variation on spatial patterns of vegetation distribution in the cerrado landscape. I monitored diurnal and seasonal changes in water table depth along two tree-density and topographic gradients. In addition, I measured woody species composition, growth rates of four tree species, litter production, soil nutrients, and nutrient resorption efficiency along those two gradients. I found that water table depth has an important role in determining the spatial distribution of cerrado physiognomies; it also affects tree growth, species composition and nutrient resorption efficiency. (3) In the Everglades I studied patterns of underground water uptake by two vegetation types. I monitored seasonal and diurnal changes in water table depth in a Hammock forest, in a stand dominated by the invasive woody species Schinus terebinthifolius, as well as the water level in an adjacent lake. I estimated stand level transpiration using two different approaches: with sap flow measurements and diurnal oscillations in water table levels. Then, I calculated the total quantity of groundwater withdrawn by evapotranspiration for the wet and dry seasons in the Hammocks and in the exotic invaded site and then compared the results. I found that water uptake by Everglades trees is well coupled to diurnal changes in water table depth and that the amount of water withdrawn from the groundwater was larger during the wet season than during the dry season. Finally, I detected hydrological feedbacks between different vegetation types and nearby bodies of water. Results of this study contributes to the current knowledge of ecosystem level processes in tropical and subtropical ecosystems where water circulation and water availability play a dominant role in shaping vegetation structure and function.

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Thesis (M.A.)--Indiana University, 2010. / Title from screen (viewed on February 26, 2010). Department of History, Indiana University-Purdue University Indianapolis (IUPUI). Advisor(s): Jason M. Kelly, Annie Gilbert Coleman, Monroe H. Little. Includes vitae. Includes bibliographical references (leaves 120-125).

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Research report on the reliability of results of Lithuanian forest inventories is given in the thesis. Aim of research – to estimate the reliability of the results of National forest inventory, Stand-wise forest inventory and forest inventory before cutting. Object of research – spruce and birch stands of Lithuanian forests. Methods of research – sampling, verification of statistical hypotheses and comparison of averages. Results of research – the reliability analysis of the results of National forest inventory shows, that calculated differences are statistically inconsequential. The reliability analysis of the results of Stand-wise forest inventory shows, that Stand-wise forest inventory results has allowed errors, except the height. The estimation of the reliability of results of forest inventory before cutting demonstrates that the errors are too high and the inequality of total volume of stands is -11,1 %.

Old-growth stands are important for management, conservation, wildlife, recreation, and maintaining biological diversity in forested landscapes. However, we are lacking the information needed to adequately identify and characterize old-growth stands. This is especially true for high elevation, interior forests. The characterization of stand structure and regeneration pattern will help in the development of site-specific guidelines for identifying old growth stands and restoring some of the old-growth characteristics in managed stands. This pamphlet presents a synopsis of a study investigating stand structure and regeneration of old-growth stands in the Moist Cold Engelmann Spruce - Subalpine Fir (ESSFmc) Subzone near Smithers, B.C. The three stands selected for the study were located on zonal sites, each in different watersheds, and the stands were established after fire. The criteria used for selection were: i) absence of lodgepole pine, ii) presence of advanced regeneration, and iii) abundant snags and coarse woody debris. These stands were presumed to represent the old-growth stage of stand development or the final (climax) stage of secondary succession.