L'objectif de cette thèse est de concevoir et d'analyser des schémas numériques performants pour la simulation d'écoulements complexes en milieux poreux. Dans un premier temps nous proposons un schéma CVFE (Control Volume Finite Element) non-linéaire pour approcher la solution de l'équation de Richards anisotrope. La mobilité d'arête est gérée à l'aide d'une procédure de décentrement. On montre d'abord que ce schéma est non-linéairement stable, qu'il admet (au moins) une solution discrète et que la saturation est bornée entre 0 et 1. Ce schéma converge sans restriction sur le maillage. Enfin, en vue de mettre en évidence l'efficacité, la stabilité et la robustesse de la méthode, nous réalisons des tests numériques dans des cas isotropes et anisotropes. Dans un second temps on étudie un schéma Volumes finis (avec décentrement des mobilités) pour un modèle d'intrusion saline. Il préserve au niveau discret les principales propriétés du problème continu: l'existence de solutions discrètes positives, la décroissance de l'énergie et le contrôle de l'entropie et sa dissipation. Nous montrons que ce schéma converge. De plus, nous illustrons numériquement le comportement du modèle. Enfin nous étudions le comportement en temps long d'un modèle d'intrusion saline. Il s'agit d'identifier les états stationnaires qui sont les minimiseurs d'une énergie convexe. On montre pour le problème continu l'existence et l'unicité des minimiseurs de l'énergie, que les minimiseurs sont des états stationnaires et que ces états stationnaires sont radiaux et uniques. Nous donnons une illustration numérique des états stationnaires et nous exhibons le taux de convergence. / This thesis is focused on the design and the analysis of efficient numerical schemes for the simulation of complex flows in porous media. First, we propose a nonlinear Control Volume Finite Element scheme (CVFE) in order to approximate the solution of Richards equation with anisotropy. This scheme is based on a suitable upwinding of the mobility which allows the negative transmissibility coefficients. We prove the nonlinear stability of the scheme, that there exists (at least) one discrete solution and that the saturation belongs to the interval [0,1]. Moreover, the convergence of the method is proved as the discretization steps tend to 0. We give some numerical experiments on isotropic and anisotropic cases illustrate the efficiency of the method. Second, we propose and analyze a finite volume scheme based on two-point flux approximation with upwind mobilities for a seawater intrusion model. The scheme preserves at the discrete level the main features of the continuous problem, namely the nonnegativity of the solutions, the decay of the energy and the control of the entropy and its dissipation. We show the convergence of this scheme. Numerical results are provided to illustrate the behavior of the model. Finally, the large time behaviour of the seawater intrusion model is studied. The goal is to identify the steady states which are the minimizers of a convex energy. We prove for the continuous problem the existence and uniqueness of the minimizers of the energy, that the minimizers are stationary states and that these stationary states are radial and unique. We give numerical illustrations of the stationary states and we exhibit the convergence rate.

<p>Benzodiazepines are drugs used to treat insomnia and anxiety. This group of drugs should be prescribed with the duty of care to the elderly because of it´s negative effects. Life expectancy is increasing because of the progress of drug development. Aging brings physical and psychological changes leading to changes in pharmacokinetic and pharmacodynamic features. Drug treatment is becoming increasingly widespread and contributes to the increasing number of interactions and complications for the elderly. The aim of the study was to illuminate the consequences of long-term use of benzodiazepines in the elderly. The study was conducted as a literature review based on 14 scientific articles that were analyzed. The result showed that the theme benzodiazepine use among the elderly could be divided into three categories; consequences out of long-term use, benzodiazepine users experiences and the nursing perspective. The category of impact out of long-term use of benzodiazepines revealed three sub-categories: physical consequences, psychological consequences and social consequences. Information and education to the elderly patients is important to make the elderly aware of the negative effects that may arise out of a long-term use of benzodiazepines. It is essential that nurses already in their basic education acquire more knowledge about benzodiazepine use among elderly in order to address these problems in the nursing care.</p>

Thesis (Ph. D.)--Washington State University, December 2006. / Includes bibliographical references (p. 148-156).

Benzodiazepines are drugs used to treat insomnia and anxiety. This group of drugs should be prescribed with the duty of care to the elderly because of it´s negative effects. Life expectancy is increasing because of the progress of drug development. Aging brings physical and psychological changes leading to changes in pharmacokinetic and pharmacodynamic features. Drug treatment is becoming increasingly widespread and contributes to the increasing number of interactions and complications for the elderly. The aim of the study was to illuminate the consequences of long-term use of benzodiazepines in the elderly. The study was conducted as a literature review based on 14 scientific articles that were analyzed. The result showed that the theme benzodiazepine use among the elderly could be divided into three categories; consequences out of long-term use, benzodiazepine users experiences and the nursing perspective. The category of impact out of long-term use of benzodiazepines revealed three sub-categories: physical consequences, psychological consequences and social consequences. Information and education to the elderly patients is important to make the elderly aware of the negative effects that may arise out of a long-term use of benzodiazepines. It is essential that nurses already in their basic education acquire more knowledge about benzodiazepine use among elderly in order to address these problems in the nursing care.

Intensive management of short rotation hybrid poplar (HP) plantations on agriculture land has demonstrated good early yields and promise as an alternative crop for farmers selling fibre to the forest industry. However, multiple rotations of HP may impact the future productivity of plantations through nutrient removals. The objectives, therefore, of this study were to determine the nutrient stores and fluxes for two HP plantations with differing site quality, fertilizer applications and past land management practices and to construct a 20-year nutrient budget to examine impacts of harvesting short rotation HP on long-term productivity.<p>Heights and biomass were measured by harvesting above- and below-ground and separating biomass into tree components; measurement of atmospheric deposition, mineral weathering, litterfall, litter decomposition, and leaching for HP plantations on an Alfalfa (HPA) and Pasture (HPP) sites in 2004-05. The budget was developed by averaging fluxes over 2 years and scaling up to a 20-year rotation. <p>Unfertilized treatments in the HPA plantation showed greater tree growth than all other treatments. Fertilized and unfertilized treatments had greater biomass production and nutrient pools than treatments at the HPP plantation. The fertilizer treatments did not affect on biomass production and nutrient accumulation.<p>Nutrient additions to the HPA were greater than the HPP plantations for leaf litterfall and leaching. Nutrient resorption from senescing leaves was greater at the HPP plantation suggesting that nutrient pools were smaller and that trees responded by keeping nutrients in the biomass. Fertilization at both plantations increased nutrient flow for inputs and outputs in 2004-05. Water leachate and leaf litterfall showed increased nutrient contents in fertilized treatments at both plantations.<p>A high fertility plantation that used fertilizer and practiced whole-tree harvesting exported more nutrients (and fibre) than a plantation with marginal site quality practicing stem-only harvesting. Time to replenish nutrients from atmospheric deposition and mineral weathering would range from 6 to 50 years for Ca and N, respectively, suggesting that subsequent plantations would require fertilizers to replenish soil nutrient reserves.<p>While HP plantations in Saskatchewan can produce high yields, they require large nutrient inputs and are inefficient (sequester a large amount) in nutrient use. High site quality is important to obtain high yields but conservational techniques, such as stem-only harvesting, are important in maintaining site quality over the long-term.

This thesis develops a novel robust periodogram method for detecting long memory. Though many test for long memory are based on the idea of linear regression, there exists no results in statistical literature on utilizing the robust regression methodology for detection of long memory. The advantage of the robust regression is a substantially less sensitivity to atypical observations or outliers, compared to the classical regression that is based on the least squares method. The thesis suggests two versions of the robust periodogram methods based on the least quan- tile and the least trimmed methods. The new robust periodogram methods are shown to provide smaller bias in long memory estimation when compared with the classical periodogram method. However, variability of estimation is increased. Therefore, we develop the bootstrapped modification of the new robust periodogram methods to reduce variability of estimation. The new bootstrapped modi¯cations of the robust periodogram tests substantially reduce variance of estimation and provides a competitively low bias. All proposed robust methods are illustrated by simulations and the case studies on currency exchange rates, and comparative analysis with other existing tests for long memory is carried out.

Den ökade användningen av nätuppkopplade mobilapplikationer har resulterat i en överbelastning i 3G-nätet. Förslag för att avlasta nätet har bland annat varit genom alternativa uppkopplingar, vilket innebär en uppoffring av 3G-nätets tillgänglighet. Detta leder till frågor om andra avlastningsmetoder. Arbetets målsättning var att se hur en applikations datatrafik påverkas av att klassiska intervallanrop ersätts av avvaktande AJAX-anrop. Detta görs genom att implementera respektive anropsmetod i två identiska alfapetapplikationer. Mätdata erhölls genom att låta användare spela längre omgångar av respektive applikation, vilket även genererar realistiska uppdateringar. Resultaten visar att den klientgenererade bandbreddskonsumtionen minskas vid användning av avvaktande AJAX-anrop. Detta gör den, i kontrast med klassiska intervallanrop, till en möjlig avlastningsmetod.

This thesis develops a novel robust periodogram method for detecting long memory. Though many test for long memory are based on the idea of linear regression, there exists no results in statistical literature on utilizing the robust regression methodology for detection of long memory. The advantage of the robust regression is a substantially less sensitivity to atypical observations or outliers, compared to the classical regression that is based on the least squares method. The thesis suggests two versions of the robust periodogram methods based on the least quan- tile and the least trimmed methods. The new robust periodogram methods are shown to provide smaller bias in long memory estimation when compared with the classical periodogram method. However, variability of estimation is increased. Therefore, we develop the bootstrapped modification of the new robust periodogram methods to reduce variability of estimation. The new bootstrapped modi¯cations of the robust periodogram tests substantially reduce variance of estimation and provides a competitively low bias. All proposed robust methods are illustrated by simulations and the case studies on currency exchange rates, and comparative analysis with other existing tests for long memory is carried out.

Intensive management of short rotation hybrid poplar (HP) plantations on agriculture land has demonstrated good early yields and promise as an alternative crop for farmers selling fibre to the forest industry. However, multiple rotations of HP may impact the future productivity of plantations through nutrient removals. The objectives, therefore, of this study were to determine the nutrient stores and fluxes for two HP plantations with differing site quality, fertilizer applications and past land management practices and to construct a 20-year nutrient budget to examine impacts of harvesting short rotation HP on long-term productivity.<p>Heights and biomass were measured by harvesting above- and below-ground and separating biomass into tree components; measurement of atmospheric deposition, mineral weathering, litterfall, litter decomposition, and leaching for HP plantations on an Alfalfa (HPA) and Pasture (HPP) sites in 2004-05. The budget was developed by averaging fluxes over 2 years and scaling up to a 20-year rotation. <p>Unfertilized treatments in the HPA plantation showed greater tree growth than all other treatments. Fertilized and unfertilized treatments had greater biomass production and nutrient pools than treatments at the HPP plantation. The fertilizer treatments did not affect on biomass production and nutrient accumulation.<p>Nutrient additions to the HPA were greater than the HPP plantations for leaf litterfall and leaching. Nutrient resorption from senescing leaves was greater at the HPP plantation suggesting that nutrient pools were smaller and that trees responded by keeping nutrients in the biomass. Fertilization at both plantations increased nutrient flow for inputs and outputs in 2004-05. Water leachate and leaf litterfall showed increased nutrient contents in fertilized treatments at both plantations.<p>A high fertility plantation that used fertilizer and practiced whole-tree harvesting exported more nutrients (and fibre) than a plantation with marginal site quality practicing stem-only harvesting. Time to replenish nutrients from atmospheric deposition and mineral weathering would range from 6 to 50 years for Ca and N, respectively, suggesting that subsequent plantations would require fertilizers to replenish soil nutrient reserves.<p>While HP plantations in Saskatchewan can produce high yields, they require large nutrient inputs and are inefficient (sequester a large amount) in nutrient use. High site quality is important to obtain high yields but conservational techniques, such as stem-only harvesting, are important in maintaining site quality over the long-term.

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