Certain scientific application domains, such as High-Energy Physics or Earth Observation, are expected to produce several Petabytes (220 Gigabyes) of data that is analyzed and evaluated by the scientists all over the world. In the context of data grid technology, data replication is mostly used to reduce access latency and bandwidth consumption. In this thesis, we adopt the typical Data Grid architecture, three kinds of nodes: server, cache, and client nodes. A server node represents a main storage site. A client node represents a site where data access requests are generated, and a cache node represents an intermediate storage site. However, the access latency of the hierarchical storage system may be of the order of seconds up to hours. The static replication strategy can be used to improve such long delay; however, it cannot adapt to changes of users¡¦ behaviors. Therefore, the dynamic data replication strategy is used in Data Grids. Three fundamental design issues in a dynamic replication strategy are: (1) when to create the replicas, (2) which files to be replicated, and (3) where the replicas to be placed. Two of well known replication strategies are Fast-Spread and Cascading, which can work well for different kinds of access patterns individually. For example, the Fast-Spread strategy works well for random access patterns, and the Cascading strategy works well for the patterns with the properties of localities. However, for so many different access patterns, if we use a strategy for one kind of access patterns and another strategy for another kind of access patterns, the system may become too complex. Therefore, in this thesis, we propose one strategy which can work for any kind of access patterns. We propose a replication approach, a Different Threshold (DT) approach to data replication in Data Grids, which can be dynamically adapted to several kinds of access patterns and provide even better performance than Cascading and Fast-Spread strategies. In our approach, there are different thresholds for different layers. Based on this approach, first, we propose a static DT strategy in which the threshold at each layer is fixed. So, by carefully adjusting the difference between the thresholds Ti, where i is the i-th layer of the tree structure, we can even provide the better performance than the above two well-known strategies. Moreover, among large amount of different data files, there may exist some hot data files. Those files which have been mostly requested are hot data files. To reduce the number of requests for the hot files, next, we propose the dynamic DT strategy. In the dynamic DT strategy, each data file even has its own threshold. We let data replication of hot files occur earlier than others by decreasing the thresholds of hot files earlier than the normal ones. From our simulation results, we show that the response time in our static DT strategy is less than that in the Cascading and the Fast-Spread strategies. Moreover, we can show that the performance of the dynamic DT strategy is better than that of the static DT strategy.

This thesis takes a step back to evaluate the architecture of the isolated Nordic home, where the exterior wall, or facade, stands out as the element with most potential for creating less isolated living conditions. As the physical threshold between domains of seemingly opposite social dynamics, the domestic- and the public; The façade serves as buildings most instrumental tool for establishing the relationship between the two. In their current state, however, as two-dimensional walls, facades have become limited in their ability to merge these two seamlessly. From having been a spatial composition of distinct elements –each with their own functions, facades of today have been reduced to only the outermost wrapping around buildings. However, when synthesizing research by architects R. Koolhaas, D. Leatherbarrow, M. Mostafavi and P. M. Martinelli, it becomes clear that contemporary facades are better understood as sealing systems that together with the rest of the buildings comprise the protective envelope around buildings. Therefore, in order to reverse the notion of facades only being superficial skins, and in hopes to create a more gradual separation between private homes and their public surroundings, this thesis speculates how facades could be distilled into distinct elements in order to be reintroduced as layers of a more spatial composition again. This new “Domestic Façade” then, as an assembly spanning between the interior and exterior, would compose an inhabitable threshold that facilitates free movement and living between the private unit and its public surroundings.

Peanut, Arachis hypogaea (L.), provides good rotational benefits for subsequent crops. During 2017, 2018, and 2019, research was conducted to determine the defoliating caterpillar complex in peanut in Mississippi, create a sweep net threshold for the complex, and determine yield losses associated with defoliation. The complex is comprised of yellow-striped armyworm, Spodoptera ornithogalli (Guenée); soybean looper, Chrysodeixis includens (Walker); corn earworm, Helicoverpa zea (Boddie); fall armyworm, S. frugiperda (Coquillet); southern armyworm, S. eridania (Stoll); beet armyworm, S. exigua (Hübner); green cloverworm, Hypena scabra (Fabricius); velvetbean caterpillar, Anticarsia gemmatalis (Hübner); and granulate cutworm, Feltia subterranea (F.). There was a significant relationship between the number of caterpillars on a drop cloth and the number per 25 sweeps. Defoliation during vegetative and early reproductive stage peanut caused a delay in canopy closure for all levels of defoliation although yield losses of 11.2% only occurred when defoliation reached 100%. During late season, peanut yield was reduced by 13% when defoliation reached 50%. With these data, a sweep net sampling and defoliation threshold can be derived. Managing caterpillar pests all season is necessary to reduce chances of yield loss due to defoliation.

Corrosion of household copper plumbing infrastructure can cause pipe failure and lead to elevated levels of copper in drinking water which can exceed the USEPA health based standard for copper in drinking water of 1.3 mg/L Cu. The purpose of this study was to determine taste thresholds of copper in different types of water, analyze how copper chemistry can affect tasting, determine if common disinfectants influence the taste of copper and evaluate genetic links to copper sensitivity. A one-out-of-five test was used to define thresholds, evaluate disinfectant influences, and examine copper chemistry differences. A difference from control test was used to analyze soluble copper tasting and a one solution test with visual classification was used to discriminate 6-n-propylthiouracil (PROP) taster status. Solutions containing copper sulfate (0.05 – 8 mg/l Cu) were prepared in distilled water, mineral water of varying pH and mineral water with disinfectant added. Geometric mean copper taste thresholds were 0.48 mg Cu/l and 0.41mg Cu/l in distilled and mineral water pH 7.4 respectively. Logistic regression copper taste thresholds were 1.50 mg Cu/l and 1.96 mg Cu/l in distilled and mineral water pH 7.4 respectively. Soluble copper was readily tasted while particulate copper was poorly tasted. Chlorine and chloramines dosed at typical tap water levels had no significant effect on panelists' tasting abilities for water containing 1 mg/l total copper. Geometric mean copper thresholds values did not correlate with (PROP) status so PROP sensitivity would not be a good indicator for copper sensitivity. / Master of Science

The brown stink bug, Euchistus servus (Say), is a polyphagous pest of multiple cultivated hosts in Virginia. It recently emerged as a potentially devastating pest of maize, Zea mays L. (Poaceae), in eastern Virginia where small grain (e.g., wheat, rye) production is common. In order to develop an integrated pest management (IPM) plan, research is needed to determine if brown stink bug feeding causes economic damage in maize at different growth stages and levels of infestations. Experiments were conducted in 2018 and 2019 to determine: 1) effectiveness of seed applied and in-furrow chemical control methods, 2) infestation levels in seedling and reproductive growth stages that cause economic damage, and 3) the effect, if any, of E. servus feeding on grain quality and mycotoxin contamination. Results of these experiments demonstrated that infestation levels (i.e., number of bugs divided by number of plants) of 11% and 15% in seedling and late vegetative maize, respectively, can cause measurable yield reduction at harvest. Seedling damage from E. servus is significantly mitigated by neonicotinoid seed treatments which are applied to nearly all commercial maize seed. Further, experiments indicated that maize quality can be affected by E. servus feeding in late reproductive stages of development. Results of these experiments will help to inform Virginia maize producers of the need to manage E. servus throughout the growing season. / Master of Science in Life Sciences / The brown stink bug, Euschistus servus, has emerged as a potential economic pest of maize (commonly referred to as "corn" or "field corn") in Virginia following reduced broad-spectrum insecticide use and increased adoption of no-tillage or reduced-tillage crop production systems. Stink bug infestations in maize frequently occur at two times in the growing season: following cover crop termination and following small grain harvest. We need to determine the effects of brown stink bug infestations on maize yield and quality, as well as the effectiveness of chemical management options, to help minimize yield losses and input costs for maize producers in our region. Experiments were conducted to determine: 1) the control provided by insecticidal seed treatments and in-furrow insecticide applications, 2) the level of brown stink bug infestations that cause economic damage at different growth stages of maize, and 3) the effect of brown stink bug feeding and a Fusarium fungal pathogen on grain yield and quality. Results of these experiments determined economic injury levels in seedling corn and late vegetative stages. Additionally, we found that universally applied neonicotinoid seed treatments mitigated early damage. Further, stink bug feeding through reproductive stages of development can reduce grain quality. Our results will help Virginia maize producers to make informed pest management decisions throughout the season.

Generalised polyneuropathy (PNP) is a common cause to neurological impairment, and may be an early symptom of a severe systemic disease. One such illness is hereditary transthyretin (TTR) amyloidosis (ATTR), a progressive fatal disorder caused by a mutation on the TTR gene. More than 100 such mutations have been found worldwide, of which Val30Met is the most common neuropathic variant with initial clinical manifestations indicating small fiber impairment. Differences in onset age, penetrance and phenotypes are present between endemic areas. Liver transplantation generally slows the progress of the symptom development, especially in patients with short disease duration. Ongoing research has also shown promising results with drug interventions. In any event, early diagnosis of PNP onset in ATTR patients is crucial to ensure early therapeutic interventions. Nerve conduction studies (NCS) and electromyography (EMG) provide the basis for evaluation of the functional state of the thick myelinated nerve fibres in patients with symptoms of PNP, but no such quantitative methods are available for the thin myelinated or unmyelinated fibers. Instead, a psychophysical method with thermal quantitative sensory testing (QST) can provide indirect information about the overall function in the afferent small fiber systems. The purpose of thesis was to evaluate the applicability of QST by the Method-of-limits (MLI) for early detection of PNP in Swedish ATTR patients with the Val30Met mutation. In healthy subjects the repeatability of the MLI was assessed, and reference values for thermal perception thresholds (TPT) in several body regions were determined. No significant differences in TPT or pain thresholds were found at repeated testing with MLI, indicating that the MLI is a reliable method. However, the results show that the arrangement of the testing order is of importance, as cold (CT) and warm (WT) perception thresholds were significantly elevated when tested after thermal pain assessments, instead of before. I general, the TPT was more elevated at lower parts of the body compared to the upper part, and with higher WT than CT, fully in accordance with the underlying anatomical and physiological prerequisites for QST. In biopsy verified ATTR patients lacking EMG and NCS abnormalities, significantly elevated TPT were found compared to controls. Furthermore, significantly more increased TPT were observed in patients with an early onset of the disease, compared those with a late onset. Finally, a combined detailed evaluation of QST and heart rate variability (HRV) analyses demonstrated correlations between QST and HRV abnormalities in patients with late onset, but not in those with early onset. The present thesis emphasizes the importance of incorporating QST early in the clinical evaluation of ATTR patients with a Val30Met mutation and with symptoms of thin fiber PNP. This is particularly indicated when patients report symptoms, or show signs, of neuropathic small fiber affection, but simultaneously exhibit normal EMG and NCS findings. The results furthermore underline the importance of performing both QST and HRV for a complete evaluation of both the thin somatic and autonomic nerve fibers, as both types of nerves may be affected early in the ATTR disease.

Monitoring and mapping the presence and/or intensity of an environmental hazard through space, is an essential part of public health surveillance. Radon, a naturally occurring radioactive carcinogenic gas, is an environmental hazard that is both the greatest source of natural radiation exposure in human populations and the second leading cause of lung cancer worldwide. Concentrations of radon can accumulate in an indoor setting, and, though there is no safe concentration, various guideline values from different countries, organizations and regions provide differing threshold concentrations that are often used to delineate geographic areas at higher risk. Radon maps demarcate geographic areas more prone to higher concentrations but can underestimate or overestimate indoor radon risk depending on the concentration threshold used. The goals of this thesis are to map indoor radon risk in the province of British Columbia, identify areas more prone to higher concentrations and their associations with different radon concentration thresholds and lung cancer mortality trends. The first analysis was concerned with developing a data-driven method to predict and map ordinal classes of indoor radon vulnerability at aggregated spatial units. Spatially referenced indoor radon concentration data were used to define low, medium and high classes of radon vulnerability, which were then linked to regional environmental and housing data derived from existing geospatial datasets. A balanced random forests algorithm was used to model environmental predictors of indoor radon vulnerability and predict values for un-sampled locations. A model was generated and evaluated using accuracy, precision, and kappa statistics. We investigated the influence of predictor variables through variable importance and partial dependence plots. The model performed 34% better than a random classifier. Increased probabilities of high vulnerability were found to be associated with cold and dry winters, close proximity to major river systems, and fluvioglacial and colluvial soil parent materials. The Kootenays and Columbia-Shuswap regions were most at risk. We built upon the first analysis by assessing the difference between temporal trends in lung cancer mortality associated with areas of differing predicted radon risk. We assessed multiple scenarios of risk by using eight different radon concentration thresholds, ranging from 50 to 600 Bq m-3, to define low and high radon vulnerability. We then examined how the following parameters changed with the use of a different concentration threshold: the classification accuracy of each radon vulnerability model, the geographic characterizations of high risk, the population within high risk areas and the differences in lung cancer mortality trends between high and low vulnerability stratified by sex and smoking prevalence. We found the classification accuracy of the model improved as the threshold concentrations decreased and the area classified as high vulnerability increased. The majority of the population were found to live in areas of lower vulnerability regardless of the threshold value. Thresholds as low as 50 Bq m-3 were associated with higher lung cancer mortality trends, even in areas with relatively low smoking prevalence. Lung cancer mortality trends were increasing through time for women, while decreasing for men. We suggest a reference level as low as 50 Bq m-3 is justified for the province. / Graduate

Dwelling on Thresholds reflects upon different modes of living/being, how we feel in different rooms and whom we decide to share space with. It asks how the spaces we dwell in affect our ability to access common and private spheres when needed or wanted. Along the way, tactility has come to play a big part in the work which has visually crystallized into a 30 m2 threshold curtain made up of floor plans of all apartments I have lived in over the past 10 years. An abstract information graphics with textures and colour nuances reflecting levels of well-being, alienation and moods in-between. The accompanying publication investigates our constructed environment as well as modes of thinking and dwelling in ‘the common’.

The Snake River flows across the dynamically uplifting hotspot plume of the Yellowstone region, cuts through the Snake River Range and ultimately enters the lowlying eastern Snake River Plain. Thermal and mantle-dynamic uplift around Yellowstone has been recorded by short-term geodesy and modeled by geophysicists, but measurements over Quaternary timescales and an understanding of how that uplift influences regional incision are absent. The Snake River is the only regional river that crosses the uplifting Yellowstone Plateau and flows into the subsiding eastern Snake River Plain (SRP), and provides an opportunity to investigate both ends of the phenomenon on the tailing margin of the Yellowstone region. This thesis consists of two related studies conducted in Alpine Canyon of the Snake River. The first is a study of fluvial terraces and steepness patterns along the Snake River considering the spatial distribution of bedrock or varying hardness and resistance to erosion and in the context of regional tectonics. This study uses surficial mapping, optically stimulated luminescence (OSL) dating, bedrock strength measurements, and steepness analyses of the mainstem Snake River and tributary drainages. Results include the first incision rate estimates for the southwestern part of the Yellowstone hotspot region and a discussion of the possible sources of baselevel fall along the Snake River. The second study documents the transitions between bedrock and alluvial channels in the study area and evaluates morphometric and transport capacity thresholds between these reaches. Alluvial bed-cover mapping with a side-scan sonar along with channel morphometric data, clast-counts, and sediment transport estimates allow us to explore what controls these two fundamental channel types. Results confirm that the Snake River has relatively fast incision rates for the interior western U.S. and that the Snake River is adjusting to an actively deforming landscape. Additionally, our dataset provides field documentation of the magnitude of bedrock-alluvial transitions and may be valuable for parameterizing landscape evolution models or assisting in the restoration of reaches that are in disequilibrium due to changes in land use or climate. This study will hopefully inspire future studies of tectonism and landscape evolution of the Yellowstone hotspot region.

<p>Using a conditioning paradigm and an automated olfactometer, I investigated the olfactory sensitivity of five CD-1 mice for seven aromatic aldehydes. With two of the stimuli (3-phenylpropanal and canthoxal), the animals discriminated concentrations as low as 10 ppb (parts per billion) from the odorless solvent and with four of the stimuli (helional, cyclamal, lilial and lyral) they discriminated concentrations as low as 1 ppb, with single individuals even scoring better. All five animals yielded the by far lowest threshold value with bourgeonal and discriminated a concentration of 0.1 ppq (parts per quadrillion) from the odorless solvent. The detection threshold values for aromatic aldehydes were found to be affected by the type of functional groups and oxygen moiety attached to the benzene ring. A comparison of the present data with those obtained in other species found no clear correlation between olfactory sensitivity and the size of the olfactory receptor repertoire.</p>