The biogeography of Central America is considered a classical case study in understanding the impact of vicariant events on patterns of biotic dispersal. While many biogeographers have focused on community composition and geographic limits of species at broad scales across Central America, much less work has focused on post-colonization diversification patterns at finer scales. The livebearing freshwater fish Xenophallus umbratilis presents an ideal system for determining the impact of recent earth history events on biodiversity in northern Costa Rica. Here, we test the hypothesis that marine inundation of the San Carlos and Northern Limón basins during the Miocene has caused genetic fragmentation among X. umbratilis populations, despite contemporary freshwater connections across this region. To test this idea, we collected mitochondrial (cytb) and nuclear (Xmrk-2) DNA sequence data from up to 162 individuals taken from 27 localities across northern Costa Rica. We employed a variety of analytical approaches, including: maximum parsimony (MP) and maximum likelihood (ML), analysis of molecular variance (AMOVA), nested clade phylogeographic analysis (NCPA), and demographic analysis of population size through time. We found four major clades within X. umbratilis, each geographically isolated with no shared haplotypes across drainages. Oddly, clades that occupy adjacent drainages are not always sister taxa in the phylogeny, suggesting that colonization in this species is more complex than a simple model of isolation by distance. All our results are consistent with the hypothesis that changes in sea level associated with glacial eustatic cycles have had an important effect in shaping diversification patterns in this species.

In the course of studying the effects of programming in multiple languages, we unearthed troubling trends in SourceForge artifacts. Our initial studies suggest that programming in multiple languages concurrently negatively affects developer productivity. While addressing our initial question of interest, we discovered a pattern of monolithic commits in the SourceForge community. Consequently, we also report on the effects that this pattern of commits can have when using SourceForge as a data-source for temporal analysis of open source projects or for studies of individual developers.

The widespread loss and degradation of habitat constitutes the largest threat to biodiversity in North America. While regulatory programs such as the Endangered Species Act of 1973 and wetland permitting under the Clean Water Act have addressed acute assaults on critical habitat, large areas of unprotected uplands have been lost. Urban development, particularly the advent of lower density suburban and rural sprawl, has greatly diminished the extent of contiguous patches of forest habitat and introduced a host of other undesirable effects on ecosystem function. This study sought to evaluate the extent of urban sprawl and its effects on ecological integrity in Florida using Landsat-derived land cover data collected by the Florida Fish and Wildlife Conservation Commission (FWC) circa 1987 and 2003. Chapter 1 described a novel GIS technique for correcting the systematic errors in the FWC 1987 and 2003 land cover data and converting those data to a common classification system so that they could be used in any ad hoc land cover change analysis. Comparison to ground-truth observations demonstrated a significant improvement in the accuracy of the land cover data following the Land Cover Correction Process (LCCP). Change detection between 1987 and 2003 using the correct land cover revealed trends in land cover conversion that were very different from previously published results derived from the original FWC land cover data. Conversion to urban uses in the corrected data was 47,293 ha lower, and conversion to agricultural uses was reduced by 196,773 ha, resulting in 244,067 ha less anthropogenic land conversion than had been previously estimated. Although the corrected land cover data showed that overall land conversion of natural areas was lower compared to the earlier estimate, the corrected data showed proportionally greater habitat losses for four important habitat types: Pinelands (-10.08% in the corrected land cover as compared to -5.90% in the original FWC data); upland forest (-9.46% versus 6.37%); sandhill (-13.90% versus 11.18%); and scrub (-15.52% versus -9.83%). Given the relatively small areal extent of some of these habitats, the larger percent loss estimates over the study period revealed by the corrected land cover data are cause for even greater concern by conservation planners and policymakers. Now that its utility has been demonstrated, the LCCP technique can be applied to any pair of roughly similar land cover mapping datasets provided that their original classification systems can be composed by a cross-walk into a single scheme, and that one or more ancillary data sets are available to serve in the tie-breaker role performed here by the land use data from Florida's Water Management Districts. The Soil Survey Geographic (SSURGO) and State Soil Geographic (STATSGO) soils data of the National Resource Conservation Service, the National Land Cover Dataset (NLCD) or the statewide habitat mapping of the USGS GAP Analysis Program could be adapted to provide the ancillary tie-breaker data required by the LCCP to conduct change detection between disparate land cover data sources heretofore considered too incompatible for that purpose. In Chapter 2, measures of urban sprawl, habitat loss and fragmentation in Florida were estimated using the corrected land cover data for 1987 and 2003. The Northwest and North regions of the state exhibited significantly higher indices of urban sprawl, habitat loss and habitat fragmentation via application of the Moran's I statistic. Reducing urban sprawl and habitat fragmentation spatial metrics to simple ordination variables through the use of non-metric multidimensional scaling produced new measures of urban sprawl and habitat fragmentation that correlated strongly with the original FRAGSTATS metrics, but could be more easily mapped and interpreted. Urban and Habitat ordination metrics were each spatially autocorrelated (Local Moran's I and K-means grouping analyses) but not correlated to each other using the Procrustes analysis PROTEST statistic (m2 = 0.952, p = 0.061). In contrast, individual urban sprawl metrics (CA, NP, LPI, ED, SHAPE_AM and DCAD) correlated with habitat fragmentation. NP and DCAD appeared to be particularly useful in predicting fragmentation, and county governments should take measures to reduce establishment of new urban patches to minimize NP and DCAD. Chapter 3 explored the relationship between environmental outcomes in habitat loss and fragmentation and the quality of county local government comprehensive plans. The use of NMS analysis provided a powerful technique for capturing the intrinsic variability of the Local Government Comprehensive Plan (LGCP) plan scoring systems of Brody (2003) and Pannozzo (2013) into a pair of variables each that could be used to explore associations with metrics of urban sprawl, habitat fragmentation and other county characteristics that influence urban growth and development. The geographic distribution of LGCP plan quality favored coastal counties with higher quality plans over inland counties, and there was some evidence that plans in Central and South regions of Peninsular Florida were superior to those in the North and Northwest Panhandle regions. Key factors in plan quality, specifically Coordination and Management, were strongly associated with urban sprawl or habitat fragmentation outcomes. The resources available to counties in the form of tax revenues, whether the county possessed a rural or urban economy, and the county's political makeup also appeared related to LGCP plan quality, urban sprawl or habitat fragmentation outcomes. More research will be needed to elucidate the specific causal mechanisms behind the implementation of local government planning that resulted in the observed environmental outcomes.

Fragmented QRS (fQRS) is a marker of conduction block due to myocardial scar that presents in electrocardiography (ECG) as an additional one or more R wave (R') or notching in the S wave nadir in contiguous leads. However, fQRS description on premature ventricular contractions (PVCs) has not been previously described. We describe a case of a 67-year-old male with a past medical history of prediabetes, hypertension and coronary artery disease who presented after an ophthalmic procedure with asymptomatic PVCs and episodes of bigeminy. Initial ECG showed an isolated fQRS in V2. However, during PVCs significant extrasystoles fragmentation was seen in other coronary territories. Upon reviewing his most recent cardiac catheterization, it showed a 40% ostial and 70% distal left anterior descending stenosis with a mid-segment patent stent, 95% first diagonal stenosis and totally occluded proximal right coronary artery. Identification of diffuse fQRS known to be associated with myocardial scar, sustained arrhythmic events and sudden cardiac death, particularly when seen in the inferior leads, became extremely relevant in our patient. We noted that ejection fraction reduction from 52% to 34% on his last coronary intervention was crucial to decide if an implantable cardioverter-defibrillator would be needed. PVC fragmentation might be a new ECG marker that could uncover both scar and arrhythmia potential in patients at risk of adverse cardiac events.

Le phénomène grandissant de morcèlement des forêts boréales matures est une source de préoccupation importante pour l'industrie forestière du Québec en raison de l'augmentation des coûts d'approvisionnement qu'il induit. Effectivement, les déplacements de machinerie plus fréquents ainsi que l'augmentation du nombre de chemins à aménager impactent la rentabilité des opérations forestières en forêt morcelée. L'évolution de ce contexte impose la recherche de solutions, incluant l'adaptation des systèmes de récolte utilisés, qui n'ont que très peu été étudiées à ce jour. Le principal objectif de cette maîtrise est d'identifier des systèmes adaptés à la récolte de forêts morcelées, permettant d'amoindrir l'impact financier du morcellement sur l'approvisionnement. Toutes les alternatives possibles se doivent d'être considérées dans la réflexion menant à l'implantation de solutions en forêt. Une approche de sélection employant des analyses successives fut préconisée, de manière à sélectionner itérativement un sous-ensemble de solutions potentielles. Dans un premier temps, une revue exhaustive des systèmes de récolte permit d'en décrire plus de 1 000 différents. De ce nombre, vingt-huit furent retenus pour leur potentiel d'application en forêt morcelée. Ceux-ci furent comparés à l'aide d'un modèle d'évaluation multicritère impliquant des experts. Sept systèmes se démarquèrent des autres, mettant en évidence l'intérêt de considérer l'implantation de systèmes actuellement inexistants au Québec. Une simulation déterministe fut réalisée afin d'estimer les coûts des solutions potentielles et ainsi affiner l'identification de la meilleure alternative. Les résultats démontrent le potentiel du système de bois tronçonnés utilisant des camions auto-chargeurs à grue détachable en contexte de forêt morcelée. L'utilisation du porteur pour charger les camions est également une alternative intéressante, notamment pour la simplicité de son adaptation par rapport au système de bois tronçonnés classique. Il serait à présent intéressant de tester ces systèmes dans un contexte opérationnel contrôlé avant d'en proposer un déploiement à plus grande échelle. / Fragmentation in mature boreal forests is a growing concern for the forest industry of Quebec, due to the increase of wood procurement costs. The more frequent machine relocations and the increasing number of roads to build and maintain compromise the profitability of fragmented operations. This changing reality needs to be addressed, starting with re-evaluating the current operational systems used in fragmented forests, which have received little attention so far. The objective of this master's degree is to identify the most cost-effective harvest systems in fragmented forests. Doing so requires a methodology compatible with the evaluation of a very wide range of potential solutions that can be implemented in these forests. The elaborated approach is based on subsequent analysis gradually reducing the number of alternatives and precising the identification of the best subset. First, an in-depth review of harvest systems resulted in the description of over 1,000 distinct alternatives. Only twenty-eight were considered as conceivable alternatives in the studied context. A multi-criteria evaluation approach involving experts from the forest industry revealed the superiority of seven potential solutions. Lastly, a deterministic simulation model was developed to estimate the harvest costs associated with each system in case studies and narrow down the selection of the best alternative. The results demonstrate the potential of the cross-cut timber system using self-loading trucks with detachable cranes in a fragmented forest context. Of the seven systems, the cut-to-length systems using either removable crane self-loader trucks or forwarders to load trucks presented lower costs in fragmented forest stands. It would now be interesting to test these systems in a controlled operational context before considering large-scale implementation.

After the accident of the STS 107 Columbia Space Shuttle, great concern has been focused on the risk associated to the population on the ground. Before this accident happened, re-entry routes as well as risk calculation of were not of public concern. Two issues that have been raised from this lamentable accident relate to spacecraft security and to public safety. The integration of a debris model has been part of the original conceptual architecture of the Virtual Range Project. Its integration has been considered as a specific research due to the complexity of the models and the difficulties to obtain them since the commercial off-the-shelf available software seems to be less accessible. This research provides solid information concerning what debris fragmentation models are, their fundamentals, their weaknesses and strengths. The research provides information of the main debris models being currently used by NASA which have direct relationship with the space programs conducted. This study also addresses the integration of a debris model into the Virtual Range Project. We created a provisional model based on the distribution of the Columbia debris fragments over Texas and part of Louisiana in order to create an analytical methodology as well. This analysis shows a way of integrating this debris model with a Geographic Information System as well as the integration of several raster and vector data sets which will provide the source data to compute the calculations. This research uses population data sets that allow the determination of the number of people at risk on the ground. The graphical and numerical analysis made can lead to the determination of new and more secure re-entry trajectories as well as further population-related security issues concerning this type of flights.

This research is focused on explaining the concentrations of mercury found in juvenile bald eagles (Halieattus leucocephallus) as a function of the physical and anthropogenic landscape. Due to it's location in the food chain this species is susceptible to a wide range of contaminants (xenobiotics), particularly those that bioaccumulate and biomagnify as they move through the food chain. Previous research has indicated that areas in coastal environments are less susceptible to methylation than those in freshwater environments. Sampling efforts for this research were conducted in such a manner as to obtain an equivalent number of samples from the coastal plain (expected to be low mercury) and the inland regions (expected to be statistically significantly higher). In all cases, results indicated that both feather and blood mercury concentrations were higher in the inland population (Blood: Prob > t = 0.0003, Feather: Prob > t = 0.0002). Utilizing classification and regression tree models (CART), we were able to relate metrics such as the percent of deciduous forest, percent of mixed forest, percent of pasture, and percent of wetland to measured blood mercury concentrations. We also found that the best models were produced using the USGS HUC 12 watersheds (the smallest watershed produced by the USGS). Moreover, we found that metrics describing the amount and type of fragmentation within the watersheds exhibited a significant influence on measured blood mercury concentrations. Contrary to previous research, we found wetlands to be negatively associated with higher blood mercury, whereas the abundance of core forest and a larger patch density (PD) in the deciduous and mixed land cover classes was positively associated with higher blood mercury concentrations. We also found that a higher percentage of pasture was associated with higher blood mercury. / Ph. D.

The web browser has emerged as a central workspace for information workers, where they make use of cloud-based applications to access their information. While this solution nicely supports access to their data from multiple devices, it presents a nightmare for organizing and coordinating data between tools for a single project. Information is typically scattered between various online tools, where storage and organization structures are replicated. Information workers are interrupted and have to switch between projects frequently. Once interrupted, resuming work on a project can be hard. To address this information fragmentation and the impact of work interruptions, I created Contextinator, a personal information manager for the web browser that lets information workers organize their work activity and information into projects. Contextinator assists in coordinating information for projects, thereby ameliorating information fragmentation for projects that live on the cloud. It assists information workers in context switching and resuming work after interruptions. In my the- sis, I describe the problem of information fragmentation in the cloud. I discuss the different areas of related work of Personal Information Management, the design of Contextinator and how it is grounded in previous research. I briefly discuss how Contextinator is implemented. I then present the results from my field-evaluation of Contextinator. Finally, I conclude by discussing future work in this research. / Master of Science

In personal task management, individual tasks are susceptible to failure at various stages due to failures in prospective memory, information fragmentation, and/or cognitive overload. To alleviate the troubles that occur in personal task management, people use various tools such as notifications and external memory aids, but there is still room for improvement in regards to maintaining distributed cognitive artifacts such as calendars and to-do lists. Improvement in staying abreast of this personal task information as opposed to being alerted of it in individual instances was the topic of exploration in this work. TaskAmbient is an ambient information display system that was designed to address these problems. TaskAmbient supports retention of individual task knowledge as well as retention of task knowledge in a user's different areas of responsibility. With this tool, I observed usage to verify or deny its ability to support prospective memory and combat the problems associated with information fragmentation and cognitive overload in respect to personal task management. In this research, studies were conducted to learn about personal task management practices and how TaskAmbient was used. In conducting these studies, I found that TaskAmbient provided value in retaining task information and staying aware of tasks in a user's various areas of responsibility. TaskAmbient showed the extendibility to other domains of personal information management. / Master of Science

Change management is an increasingly prominent and complicated topic. In the postmodern digitized society, Sweden is believed to be at the forefront, yet in Swedish radio, information experts claim that the country is far from able to manage a crisis. Experts elaborate that in a disaster where large populations must be evacuated between municipal borders, there will be complications for essential care as medical records will be locked in different systems across these borders. The digitalization authority DIGG was for this reason founded in 2018 to facilitate the development of public service, building blocks, and ensuring public service is accessible to everyone in Sweden. DIGG further assists, develops, and encourages certain merges of processes that would prepare Sweden for such crises experts warn. This paper is a qualitative case study to examine obstacles change managers in digitized postmodern society encounter while leading modern autonomous organizations to the fragmented, heterogeneous postmodern era. To explore this subject, a case study at DIGG was conducted as they act as the change agent for Swedish authorities to implement digitized solutions. The theoretical framework is built on the history and shift from modernity to postmodernity, and additionally, how change management has changed collectively with digitalization. The data was further generated through semi-structured interviews with change managers at DIGG who work closely with this task. Change managers at DIGG in the fragmented postmodern society face challenges due to the demand for customized solutions and limited flexibility from other authorities. Rigid bureaucratic structures persist, but Swedish authorities are adopting a postmodern adaptation to enhance flexibility. There is a growing emphasis on customer orientation and the development of inclusive solutions. unique approaches are needed for each change adaptation, highlighting the need for the public sector to become more individualized, customer-oriented and align with evolving needs.