It is common knowledge that invasive species cause worldwide ecological and economic damage, and are nearly impossible to eradicate. However, upon introduction to a novel environment, alien species should be the underdogs: They are present in small numbers, possess low genetic diversity, and have not adapted to the climate and competitors present in the new habitat. So, how are alien species able to invade an environment occupied by native species that have already adapted to the local environment? To discover some answers to this apparent paradox I conducted four ecological genetic studies that utilized the invasive species Brachypodium sylvaticum (Hudson) Beauv. to determine mechanisms contributing to adaptation and success in the novel habitat. The first study used simulations and experiments to test the hypothesis that genetic purging, the process where genetic load is reduced by selection against the recessive deleterious alleles expressed in the homozygous state, promotes invasive range expansion. I found that homozygous populations on B. sylvaticum's range periphery displayed lower inbreeding depression compared to heterozygous populations near introduction sites. Empirical tests with B. sylvaticum further demonstrate that purging of genetic load is a plausible scenario promoting range expansion during invasion. Next, I explored how the interaction between population genetic diversity and the environment contributed to the establishment and spread of Brachypodium sylvaticum. I found that nitrogen application increases both final size and shoot biomass for B. sylvaticum individuals from source populations with low HS levels to levels found in individuals from populations with high HS. A coefficient of relative competition intensity index (RCI) displayed reduced effects of interspecific competition on B. sylvaticum biomass in high nitrogen plots. Results show that elevated nitrogen deposition is a factor that increases establishment of introduced species with historically small effective population sizes. Thirdly, I investigated phenotypic differentiation during the establishment and range expansion of Brachypodium sylvaticum. Utilizing a novel approach, unique alleles were used to determine the genetic probability of contribution from native source regions to invasive regions. These probabilities were integrated into QST-FST comparisons to determine the influence of selection and genetic drift on twelve physiological and anatomical traits associated with drought stress. Phenotypic divergence greater than neutral expectations was found for five traits between native and invasive populations, indicating selective divergence. Results from this study show that the majority of divergence in B. sylvaticum occurred after introduction to the novel environment, but prior to invasive range expansion. The final chapter of my dissertation investigates the adaptive role of genetic differentiation and plasticity for Brachypodium sylvaticum invasion. Plasticity was measured across treatments of contrasting water availability. Linear and nonlinear selection gradients determined the effect of directional and quadratic selection on plasticity and genetic differentiation. Invasive trait divergence was a consequence of post-introduction selection leading to genetic differentiation, as there were no plastic responses to contrasting water availability for any measured traits. Genetic divergence of invasive plants was not consistently in the direction indicated by selection, suggesting limitations of selection that may be a consequence of physical constraints and/or tradeoffs between growth and abiotic tolerance. Results suggest that selection, rather than plasticity, is driving phenotypic change in the invaded environment. The combined volume of these studies contributes significantly to the field of invasion and plant biology by providing novel insights into the processes underlying range expansion, adaptation, and ultimately, evolution of introduced species.

Minimal access approaches in cardiac surgery and for procedures on the aortic valve began to develop in the 1990s. Several variations were performed in search of the most appropriate technique before the median ministernotomy was established. Despite limited exposure, difficult deairing or cardioplegia application and longer surgical times were described in the literature, surgeons believed that this technique would reduce surgical trauma and bleeding, improve chest stability, reduce pain and respiratory failure and shorten hospitalization and costs, while keeping mortality and morbidity low. The aim of this retrospective study was to review the techniques of minimal invasive surgery on the thoracic aorta in use in Heart Center Leipzig from 1998 to 2011 as well as the preoperative circumstances, intraoperative setup and early and late postoperative outcome of these patients. The results were to be integrated in the current literature and commented on. All 199 patients who underwent a procedure on the proximal aorta through minimal access incision were selected and included in this study. The procedures were completed with a standard surgical setup. Perioperative and intraoperative data were collected from surgical and discharge reports. Elective surgery was performed in 95.5% of the patients. 8.5% were redo procedures. Indication for surgery was dilatation of the proximal aorta in 92.5%, accompanied by pathology of the aortic valve in 87.9%. Access to the surgical site was L-type partial sternotomy in 59.7%. Cannulation for cardiopulmonary bypass was performed mostly through the ascending aorta or aortic arch (arterial line) and right atrium (venous line). Intermittent antegrade cardioplegia was delivered in all patients. Brain protection strategies for patients undergoing aortic arch replacement included hypothermic circulatory arrest and selective cerebral perfusion. Following procedures were performed: isolated aortic arch replacement (n=1); supracoronary ascending aorta replacement (isolated n=15, combined to aortic arch replacement n=8, combined to aortic valve replacement n=37 or combined to both n=10), and aortic root surgery (isolated aortic root replacement or repair n=95, aortic root replacement or repair combined to aortic arch replacement n=33). Cardiopulmonary bypass time was 123 ± 44 minutes. Conversion to full sternotomy was performed in 5 patients due to low cardiac output syndrome or bleeding. Thirty-day mortality was 5.0% (n=10) and ischemic stroke rate was 2.5% (n=5). Reoperation due to bleeding was performed on 13.1% (n=26). The estimated 10-year survival was 76 ± 4%. Clinical research to this subject is limited, based in studies with small populations and heterogenous procedures. Our study confirms the feasibility of minimal access proximal aortic surgery because neither inadequate exposure nor problems with deairing or cardioplegia were reported. Surgical times were shorter than described in the literature. Mortality, stroke, cardiac and sternal complication rates were low and comparable to the results in the literature. We consider that our higher reexploration rate of because of bleeding was caused primarily due to pathological coagulation state. We present the first long term results for minimal access proximal aortic surgery at 10 years. We consider that our results reflect better the risk inherent to minimal access proximal aortic surgery than studies with smaller cohorts but recognize it is limited by its retrospective form and heterogeneity of the reported procedures. Randomized prospective studies should bring more information about the safety of this procedure, but we support ministernotomy as a promising access for selected patients.

The invasion of riparian habitats by the exotic plant, Arundo donax L., commonly known as the giant reed is one of the greatest threats to ecosystems in Central and Southern California. There have been several efforts to eradicate this plant with varying control methods. This study evaluated some previously known techniques of controlling the giant reed in addition to some novel methodologies to determine the most effective approach. The study site is a section of the Lower Calaveras River that transects University of the Pacific's campus and is a prime example of the devastation caused by the giant reed. The project site was cut and cleared over a period of eight months and divided into fourteen plots. Seven different techniques including a control were selected and each treatment was randomly applied to two plots. The methods chosen were: "cut, resprout and spray", "cut-stem, spray", "chip and compost", "chip and tarp", "compost" and "compost and tarp". The response variables were the "mean regrowth height", "mean circumference of stalks" and the "number of resprouted stalks". A repeated measures ANOVA was used to analyze the response variables. The "compost and tarp" method had the lowest number of resprouted stalks and was also significantly different from the control treatment. None of the other techniques were significantly different from the control but the "compost" method showed some promise. Based on this study, the "compost and tarp" technique is the most effective treatment. The data collection for this study was limited and future experiments should be conducted on a longer time scale to assess the effectiveness of these methods. Further research should also be conducted to evaluate the effectiveness of various biotic factors on the growth of A. donax, which could enhance the efficacy of methodologies currently used to control this introduced invasive plant.

The Calaveras River is a unique riparian habitat in San Joaquin County, influenced by both tidal water from the San Francisco Bay and impounded rainwater from the New Hogan Dam. The Calaveras River is one of the few river systems in California that does not benefit from snowpack melt. This dynamic system has changed dramatically in both its species composition and hydrodynamic regime due to years of human influences. What was once a thriving population of native plant species has become an environment dominated almost completely by aggressive exotic invasive species. The goal of this project was to remove the nonnative plant habitat by the most cost effective and least labor intensive means. The study area was along a section of river that bisects the University of Pacific campus in Stockton, California. From years of invasive species presence a deep seedbank has developed within the soil which acts to reduce the effectiveness of native plant reintroductions. A technique known as "solarization" was used to eliminate the seedbank and to facilitate the survival of native plants. Tarps were used to eradicate existing plants followed by disturbance of the soil and watering to induce germination of subsoil weed seeds. As the new plant seedlings emerge, tarps are reapplied to eliminate that generation of seedbank plants. After four time series of tarping and watering, a significant difference was found between control plots and treatments utilizing the solarization technique. Treatment 2, which consisted of tarping without weight, was determined to best target the seedbank after four repetitions and resulted in reducing invasive species in the seed bank.

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第18155号 / 医博第3875号 / 新制||医||1002(附属図書館) / 31013 / 京都大学大学院医学研究科医学専攻 / (主査)教授 上本 伸二, 教授 平岡 眞寛, 教授 安達 泰治 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

京都大学 / 0048 / 新制・課程博士 / 博士(情報学) / 甲第19126号 / 情博第572号 / 新制||情||100(附属図書館) / 32077 / 京都大学大学院情報学研究科システム科学専攻 / (主査)教授 石井 信, 教授 田中 利幸, 教授 加納 学 / 学位規則第4条第1項該当 / Doctor of Informatics / Kyoto University / DFAM

京都大学 / 0048 / 新制・論文博士 / 博士(医学) / 乙第13029号 / 論医博第2111号 / 新制||医||1016(附属図書館) / 32987 / (主査)教授 大森 孝一, 教授 別所 和久, 教授 坂井 義治 / 学位規則第4条第2項該当 / Doctor of Medical Science / Kyoto University / DFAM

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第21620号 / 医博第4426号 / 新制||医||1033(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 平井 豊博, 教授 宮本 享, 教授 福田 和彦 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

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