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Seed companies have developed novel weed control technologies to combat herbicide-resistant (HR) weeds based on the use of new genetically-modified (GM) crop cultivars and auxin herbicide formulations. These herbicides can variably affect the growth and yield of susceptible cotton even at low concentrations depending on growth stage at exposure. As such, research was conducted in each of two locations in Mississippi in 2014, 2015, and 2016 to determine the cotton growth stage most susceptible to injury and yield effects from simulated misapplications of sub-lethal 2,4-D or dicamba concentrations. Results indicate that generally a decrease in yield partitioned on lower nodes and inner positions was accompanied by a compensatory increase in yield partitioned on vegetative branches and aborted terminals. However, the magnitude of these yield effects differed based on growth stage at exposure and based on which herbicide was used.

Per- and polyfluoroalkyl substances (PFASs) are a group of emerging chemicals which havereceived increasing attention due to their toxicity, persistent properties, and global distribution.In this study, sorption coefficients (Kd and KOC) of PFASs in an industrial site in Sweden wereevaluated. Sorption is a measures of the mobility of a substance in the subsurface, and is a keyfactor in environmental risk assessments. Sorption coefficients were calculated both from fieldsamples processed in laboratory batch tests, and from a simplified approach involving the totalconcentrations in soil and groundwater (field-derived). Soil was sampled from two locations ofthe site; C8 and M6. Field-derived values were calculated based on concentrations which werehistorically measured. The aim was to compare the two methods, and to compare the valueswith literature values as well as guideline sorption values established by the SwedishGeotechnical Institute (SGI). Sorption coefficients for PFHxA, PFHpA, PFOA, PFHxS, PFOS, 6:2 FTS and PFBS could beestablished. Results showed that laboratory-derived sorption coefficients were significantlyhigher than field-derived sorption coefficients. Laboratory-derived sorption values were alsohigher than to SGI’s preliminary sorption values. Comparing C8 and M6 KOC values toliterature values, PFHpA, PFHxA, and PFBS exhibit values above literature values. PFOA,PFHxS, PFOS exhibit KOC values within the range of literature values. According to thesorption coefficients, predictive scenarios of leaching through the unsaturated zone weremodelled, and it was concluded that leaching was higher in M6 compared to C8. The resultsalso showed that an increase in precipitation increased the leaching. / Per- och polyfluorerade alkylsubstanser (PFAS) är en grupp nyligen uppkomna kemikalier somhar fått ökad uppmärksamhet pga. deras toxicitet, ihärdiga egenskaper och globala utbredning.Detta examensarbete har studerat fördelningskoefficienter (Kd och KOC) för PFAS inom ettindustriområde i Sverige. Fördelningskoefficienter är ett mått på mobilitet av en substans iunderjorden, och det är en viktig komponent i riskbedömningar inom förorenad mark.Fördelningskoefficienter beräknades dels utifrån jordprover som tagits i fält och analyserats ilaboratorium med extraktionsmetoder, och dels utifrån ett förenklat tillvägagångssätt därberäkning skett med hjälp av tidigare uppmätta koncentrationer i jord och grundvatten.Jordprover från två områden inom industriområdet; C8 och M6, togs och analyserades.Fältbaserade fördelningskoefficienter beräknades utifrån koncentrationer som tidigare mättsvid brunnsinstallation och vid grundvattenövervakning. Målet med studien var att jämföra detvå metoderna, och dessutom jämföra fördelningskoefficienterna med motsvarande i värdenlitteraturen samt riktvärden för fördelningskoefficienter som Statens Geotekniska Institutet(SGI) arbetet fram. Fördelningskoefficienter för PFHxA, PFHpA, PFOA, PFHxS, PFOS, 6:2 FTS and PFBS kundeberäknas. Resultatet visade att laboratorie-baserade fördelningskoefficienter var betydligthögre än fältbaserade fördelningskoefficienter. Laboratorie-baserade fördelningskoefficientervar även högre än de preliminära riktvärden för fördelningskoefficienter som SGI etablerat. Vidjämförelse av fördelningskoefficienter för C8 och M6 kunde det konstateras att PFHpA,PFHxA, and PFBS hade högre värden än motsvarande i litteraturen. PFOA, PFHxS, PFOSvisade på värden som var inom intervallet av värdena från litteraturen. Med hjälp av deberäknade fördelningskoefficienterna modellerades prediktiva utlaknings-scenarier. Utifrånresultatet sker utlakningen i större grad i M6 jämfört med C8. Utlakningen ökade även vidförhöjd nederbörd.

Campaign GPS measurements during 2001-2003 in the transition between subduction and collision of the Banda arc reveal how strain is partitioned away from the trench and distributed to other parts of the arc-trench system. Genrich, et. al. (1996) conducted a GPS campaign (1992-1994) throughout the Eastern Sunda and Banda arcs that demonstrated partial accretion of the arc to the Australian plate. We reoccupied many of the sites from this earlier study and 7 additional stations, 3 of which are new benchmarks. Our study shortened many baselines and extended the observation epoch to ten years for many key stations. The resulting GPS velocity field for the active Banda arc-continent collision reveals: 1) several mostly rigid crustal blocks exist in the transition from subduction to collision, 2) relative to an Asian reference frame, most of these blocks move in the same direction as the Australian lower plate, but at different rates, 3) block boundaries may exist between the islands of Lombok and Komodo, Flores and Sumba, Savu and West Timor, and between Timor and Darwin, 4) the Timor Trough may account for at least 20 mm/yr of motion between Timor and Darwin, 5) a major transverse fault off the coast of West Timor separates the Savu/Flores/Sumba block from the Timor/Wetar Block and may account for variations in movement in Rote, 6) the Flores thrust moves the eastern Sunda arc north relative to Asia by decreasing amounts to the west, 7) the back-arc Wetar Thrust system takes up the majority of plate convergence between Australia and Asia, and 8) fault boundaries are not found between many blocks, such as various islands of the Sunda arc and forearc with different amounts of motion.

Modern tools, nontraditional datasets and a better understanding of the interaction between climate and ecohydrology are continuously being developed as today's society is in critical need for improving water management, predicting hydrometeorological hazards and forecasting future climate. In particular, the study of the intra- and inter-annual variations in grass productivity and evapotranspiration caused by variations in precipitation/soil moisture and other biophysical factors is of great significance due to their relation to future climatic changes. The research presented here falls in three parts. In the first part of the dissertation, a land use adaptable model, based on the superposition of the temperature and water vapor pressure effects, is proposed for the effective clear sky emissivity. Ground radiometer and meteorological data, applicable in the subtropical climate of Saint Johns River Water Management District, Florida, were utilized for the model development over the spring season of 2004. The performance of this model was systematically evaluated by pertinent comparisons with previously established models using data over various land covers. The second part of the thesis investigates the dynamics of evapotranspiration with respect to its significant environmental and biological controls over an unmanaged bahia grassland. Eddy correlation measurements were carried out at a flux tower in Central Florida over the annual course of 2004. The main focus was on the sensitivity of the water vapor flux to wetness variables, namely the volumetric soil water content and the current precipitation index. It was shown that the time scales involved with the dynamics of evapotranspiration were on the order of six days, suggesting that depletion of the soil moisture was mostly responsible for the temporal fluctuations in evapotranspiration. Finally, simple models for the Priestley-Taylor factor were employed in terms of water availability, and the modeled results closely matched the eddy covariance flux values on daily time scale during all moisture conditions. In the third part of this work, the partitioning between latent and sensible heat fluxes was systematically examined with respect to biophysical factors. It was found that the seasonal variations in leaf area index, soil water content and net radiation were reflected in a strong seasonal pattern of the energy balance. Calculations of the bulk parameters, namely Priestley-Taylor parameter and decoupling coefficient, indicated that evapotranspiration of this grassland was controlled by water supply limitations and surface conductance. At an annual basis, the cumulative evapotranspiration was 59 percent of the precipitation received at the site. The results of this research complemented with other studies will promote better understanding of land-atmosphere interactions, accurate parameterizations of hydroclimatic models, and assessment of climate impact of grassland ecosystems.

Many plant species recognize kin and respond with changes in functional traits. Researchers hypothesize that siblings compete less than strangers. However, no study has directly tested whether siblings are less competitive. Measuring natural selection on kin recognition responses in root allocation and other destructively measured traits is challenging, since trait and fitness cannot be measured on the same individual. Here, a methodology using family-level selection is developed, measuring the trait on one individual and measuring its fitness value using another related individual. Three greenhouse pot experiments were conducted using six Brassica oleracea cultivars at two nutrient levels. We investigated whether root allocation and morphological traits were under natural selection. We tested whether or not there was cultivar recognition or resource partitioning in B. oleracea. We found that putative competitive traits (size, height, emergence and root allocation) had expected patterns of individual selection for an increase in each trait and group selection for a reduction of each trait. There was no indication that resource partitioning was occurring or that B. oleracea could recognize cultivars. However, plants were experiencing competitive interactions within pots. In conclusion, we demonstrate that using family-level selection estimates the fitness consequences of root allocation and morphological traits. / Thesis / Master of Science (MSc)

The variation in community composition among sites is often used to gain insight into the processes of plant community assembly. In this study, we looked for evidence of environmentally and spatially mediated community assembly mechanisms in a temperate forest in eastern North America. To test this, we measured, identified and mapped all woody stems ≥1 cm in diameter at breast height (DBH) in 12 ha of a 20 ha forest plot. We used principal coordinates of neighbor matrices (PCNM) to obtain variables that modelled spatial processes (eg. dispersal, drift) at the community level. Topographic variables (slope, elevation, convexity, aspect) were used to model environmental conditions. Variation partitioning was used to isolate the unique and shared effects of topographic and spatial variables on community composition. We were also interested in studying how associations with the environment change with tree size. For this we assessed the abundance of a subset of focal species in response to topography as well as human disturbance. Species abundance were divided into three stem size classes: small (< 5 cm), medium (≥5 cm and < 15), and big (≥15 cm). We found that topography and space jointly explained 63% of the variation in community composition. This variation was almost entirely spatially structured with the component of pure topography only contributing 1% to the total explained variation. A redundancy analysis showed that slope and elevation were the most important topographic variables structuring the distribution of trees. The focal species had largely independent distributions across the environmental gradients and three of the five species showed within-species differences associated with size class effects on the relationship with topography and human disturbance. The implications of these results are relevant to conservation efforts and suggest that large contiguous areas of heterogeneous environments are essential in maintaining biodiversity. / Thesis / Master of Science (MSc)

Acute respiratory infections (ARI) caused by influenza and other respiratory viruses affect millions of people annually. Although usually self-limiting a more complicated or severe course may occur in previously healthy people but are more likely in individuals with underlying illnesses. The most common viral agent is rhinovirus whereas influenza is less frequent but is well known to cause winter epidemics. In primary care, rapid diagnosis of influenza virus infections is essential in order to provide treatment. Clinical presentations vary among the different pathogens but may overlap and may also depend on host factors. Predictive models have been developed for influenza but study results may be biased because only individuals presenting with fever were included. Most of these models have not been adequately validated and their predictive power, therefore, is likely overestimated. The main objective of this thesis was to compare different mathematical models for the derivation of clinical prediction rules in individuals presenting with symptoms of ARI to better distinguish between influenza, influenza A subtypes and entero-/rhinovirus-related illness in children and adults and to evaluate model performance by using data-splitting for internal validation. Data from a completed prospective cluster-randomized trial for the indirect effect of influenza vaccination in children of Hutterite communities served as a basis of my thesis. There were a total of 3288 first episodes per season of ARI in 2202 individuals and 321 (9.8%) influenza positive events over three influenza seasons (2008-2011). The data set was divided into children under 18 years and adults. Both data sets were randomly split by subjects into a derivation (2/3 of the dataset) and a validation population (1/3 of the dataset). All predictive models were developed in the derivation sets. Demographic factors and the classical symptoms of ARI were evaluated with logistic regression and Cox proportional hazard models using forward stepwise selection applying robust estimators to account for non-independent data and by means of recursive partitioning. The beta coefficients of the independent predictors were used to develop different point scores. These scores were then tested in the validation groups and performance between validation and derivation set was compared using receiver operating characteristics (ROC) curves. We determined sensitivities and specificities, positive and negative predictive values, and likelihood ratios at different cut-points which could reflect test and treatment thresholds. Fever, chills, and cough were the most important predictors in children whereas chills and cough but not fever were most predictive of influenza virus infection in adults. Performance of the individual models was moderate with areas under the receiver operating characteristic curves between 0.75 and 0.80 for the main outcome influenza A or B virus infection. There was no statistically significant difference in performance between the derivation and validation sets for the main outcome. The results have shown, that various mathematical models have similar discriminative ability to distinguish influenza from other respiratory viruses. The scores could assist clinicians in their decision-making. However, performance of the models was slightly overestimated due to potential clustering of data and the results would first needed to be validated in a different population before application in clinical practice. / Thesis / Master of Science (MSc) / Every year, millions of people are attacked by "the flu" or the common cold. Certain signs and symptoms apparently are more discriminative between the common cold and the flu. However, the decision between starting a simple symptom orientated treatment, treating empirically for influenza or ordering a rapid diagnostic test that has only moderate sensitivity and specificity can be challenging. This thesis, therefore, aims to help physicians in their decision-making process by developing simple scores and decision trees for the diagnosis of influenza versus non-influenza respiratory infections. Data from a completed trial for the indirect effect of influenza vaccination in children of Hutterite communities served as a basis of my thesis. There were a total of 3288 first seasonal episodes of ARI in 2202 individuals and 321 (9.8%) influenza positive events over three influenza seasons (2008-2011). The data set was divided into children under 18 years and adults. Both data sets were split into a derivation and a validation set (=holdout group). Different mathematical models were applied to the derivation set and demographic factors as well as the classical symptoms of ARI were evaluated. The scores generated from the most important factors that remained in the model were then tested in the validation group and performance between validation and derivation set was compared. Accuracy was determined at different cut-points which could reflect test and treatment thresholds. Fever, chills, and cough were the most important predictors in children whereas chills and cough but not fever were most predictive of influenza virus infection in adults. Performance of the individual models was moderate for the main outcome influenza A or B virus infection. There was no statistically significant difference in performance between the derivation and validation sets for the main outcome. The results have shown, that various mathematical models have similar discriminative ability to distinguish influenza from other respiratory viruses. The scores could assist clinicians in their decision-making. However, the results would first needed to be validated in a different population before application in clinical practice.

Heat treatment is a way to significantly change materials properties. When presented with materials that lack certain mechanical properties, it is possible to change its chemical properties and microstructures by applying heat. This can help achieve better yield strength, ductility and toughness. This project discusses the effects of multiple distinct heat treatment methods for several materials in order to improve ductility and elongation without diminishing strength. The materials in question are High Aluminum Steel and Strenx 700MC steel, the first being under development and the second being a commercially available steel. These steels show promise to be used as high ductility, high strength, and 3rd generation steels. The heat treatments can change the mechanical proprieties of the base materials in order to optimize these steels for applications in vertical access solutions. The heat treatments in this project were Quenching and Partitioning (QP), Quenching and Tempering (QT), Austempering (AUST), Intercritical Heat Treatment (IHT) and other usual heat treatments such as Double normalizing (D-Norm). First, the most beneficial type of the above mentioned heat treatments was selected for each steel and series of heat treatments were performed in order to identify and optimize the best method for each steel. Then, heat treated samples underwent a series of tests to numerically quantify their properties and compare them to the existing steels in Alimak’s applications. The results show that Quenching and Partitioning is the most promising heat treatment for optimizing strength and ductility in High Aluminum Steel, with elongation values up to 19% together with yield strengths of 700 MPa. For Strenx 700MC a combination of temperature and time was found that gave an elongation of above 25% with a yield strength of 450 MPa. The explanation for the good properties was partly grain refinement and phase transformations during heat treatments.

Applications of power electronics in power systems are growing very rapidly and changing the power system infrastructure in terms of operation speed and control. Even though applications of power electronics are wide spread, the cost and reliability of power electronics are the issues that could hinder their penetration in the utility and industrial systems. The demand for efficient and reliable converter controllers gave rise to modularized converter and controller design. The objective of this dissertation is to determine the appropriate partitioning and interface requirements between the system and application control layers for power electronic converters so that the minimum set of system layer to application layer control interfaces is compatible across all power electronic controllers. Previous work, using the Open System Architecture (OSA) concept has shown that there is a set of common functions shared by different converters at the low-level control layers. It has also shown that, depending on the application, there is a variation in control functions in application/middle control layers. This functional variation makes it difficult to define system functionality of power converters at upper control layers and further complicates the investigation into the partition requirements of system to application control layer. However, by analyzing the current or voltage affected by a converter in terms of orthogonal components, where each component or group of components is associated with a power-converter application, and the amount of required DC bus energy storage, a common functionality can be observed at the application control layer. Therefore, by establishing common functionality in terms of affected current or voltage components, a flexibility of operation can be realized at upper control layers that will be a major contribution towards standardizing the open system architecture. In order to a construct functional flexible power converter control architecture, the interface requirements to the system control layer and the partitioning between the system control layer and application control layer need to be explored. This will provide flexibility of system design methodology by reducing the number of constraints and enabling system designers to explore possible system architectures much more effectively.