Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 21 for “"nutrient limitations"”.
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Red spruce physiology and growth in response to elevated CO₂, water stress and nutrient limitations
… to changes in atmospheric CO₂ water and nutrient availability to determine the response of this species to potential climatic changes. Red spruce seedlings were grown from seed for 1 year in ambient (374 ppm) or elevated (713 ppm) CO₂ in combination with low or high soil fertility …
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Denitrification in sediments of headwater streams in the southern Appalachian Mountains, USA
We investigated variations in resource availability (nitrate and labile organic carbon, LOC) as determinants of denitrification in sediments of streams in the southern Appalachian Mountains, USA. Stream water and sediments were sampled seasonally in two streams of contrasting nitrate availability, …
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Deciphering Cancer Metabolic Dependencies in the Tumor Microenvironment
… tumor microenvironment. Physical constraints and nutrient limitations in the tumor prevent excessive cell proliferation, while other cell types such as stromal and immune cells can compete with or kill cancer cells. To overcome these restrictions, cancer cells often possess oncogenic mutations or …
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THE PHYSIOLOGICAL RESPONSE OF PICOPHYTOPLANKTON TO LIGHT, TEMPERATURE AND NUTRIENTS, INCLUDING CLIMATE CHANGE MODEL SIMULATIONS
… of picophytoplankton to light, temperature and nutrient limitations were conducted. The impact of climate change in a RCP8.5 model scenario simulation was investigated. An acclimated and a dynamic photosynthesis response model reproduce the physiological response to light. Long-term damage …
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Determinants of blackwaters in the South Western Cape
… compared to other types and the effects of nutrient fertilisation on microbial activity in soil were determined. The results revealed that organic carbon, Fe and pH are significantly correlated with blackwaters. The Fe in the water appears to be bound to humic compounds. Fynbos vegetation is …
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Carbon cycling: The role of Methane and Copper in an early ocean analogue Lake Matano
… or marine settings. Furthermore because of the nutrient limitations of the lake and its minimal photosynthetic activity it was shown that methane plays a key role in this carbon cycle and as a substrate for organic matter production, which in turn can be used as an energy source, and for cell …
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The Effect of Environment on Virulence Factors and Resistance of Mucoid Strains of Pseudomonas Aeruginosa
… which differed in colony size and appearance on nutrient agar. Both showed differences in the production of the virulence factors, protease, elastase, lipase, phospholipase C and pyocyanine and fluorescent pigments under different nutrient limitations. Growth conditions also affected …
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Evolution and Regulation of Virulence and Antimicrobial Resistance in Pseudomonas aeruginosa
… system allows bacteria to sense and respond to nutrient limitations and related stresses by modulating cellular transcription patterns. Notably, it has always been assumed that the stringent response is essential for the activation of QS systems, and therefore, for the expression of virulence …
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Genetics by Nutrient Availability Interactions on Short-term Carbon Pools and Fluxes in Young Pinus taeda Plantations
… this research was to determine how genetics and nutrient availability influence C cycling in intensively managed southern pine forests. This work consisted of a two year field and a complimentary one year greenhouse study each split into above- and below-ground pools and fluxes. Both the …
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Effects of Elevated Atmospheric CO₂ on Scrub-Oak Root Carbon Pools and Soil Microbial Processes
… on soil biomass pools, microbial response and nutrient limitations. Elevated CO<sub>2</sub> did not affect total biomass of roots as of May 2002. There was less biomass of the smallest roots (2 in the top 10 cm. The C and N contents of root and organic matter pools reflected the trends in …
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Ecological forces affecting microbial eukaryotes in the coastal ocean
… of growth and death rates, which are impacted by nutrient availability (bottom-up control) and predation (top-down control). In this thesis, I investigate the effect of specific top-down and bottom-up forces at fine scales of time, location, and taxonomy, uncovering mechanisms by which nutrient …
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Biofiltration of volatile organic compounds using fungal-based bioreactors
… E. lecanii-corni can tolerate low pH and minimal nutrient conditions and degrade a wide variety of contaminants including toluene and methyl propyl ketone. A series of bench-scale bioreactor studies were then conducted to determine how nitrogen supply, mite predation and surfactant washing …
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Developing DRIS norms for Fraser fir Christmas trees
… fertilize their crop, a scientifically-based nutrient diagnosis and fertilizer recommendation system is needed. The objective of this study was to develop and test DRIS norms for Fraser fir Christmas trees grown in Virginia for the ultimate purpose of establishing a nutrition diagnosis and …
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Submesoscale Biophysical Interactions on the Gulf Stream: Eddies, Fronts, and New Observational Methods
… with peak biomass in winter. We found shifting nutrient limitations and observed chlorophyll-a enhancement on the front in a large minority of samples with an indication of winter being more likely for enhancement. We speculate about linkages between this enhancement and ageostrophic circulation …
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The Utilization of Activated Sludge Polyhydroxyalkanoates for the Production of Biodegradable Plastics
… conditions with nitrogen (N) and phosphorus (P) limitations were the optimum conditions for PHA production when the laboratory prepared mixtures of orgnics were used, while fully AE with the combinations of N, P, and potassium (K) limitations were better for PHA production using a high acetic …
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Novel Polyhydroxyalkanoate blends: their characterisation and possible applications
… in the presence of excess carbon, under nutrient limiting conditions. PHAs are biodegradable and biocompatible polymers that exhibit a variety of properties ranging from being thermoplastic to elastomeric in nature. For the first part of this study, the production of PHA in Bacillus …
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Overcompensation of Ipomopsis aggregata following ungulate herbivory: getting to the root of it
… associates that could provide the necessary nutrients needed. A long-term study of the monocarpic biennial, scarlet gilia, Ipomopsis aggregata, showed that ungulate herbivory by mule deer and elk can result in a three-fold increase in plant fitness. We hypothesized that fungal associations …
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Optimization of Growth Parameters for Algal Regrowth Potential Experiments
… this medium can limit algal growth through nutrient limitation and it became necessary to augment the original recipe. 50mM of sodium bicarbonate was added to the media in order to buffer the purging of 100% CO<sub>2</sub> into the culture vessel. The resultant pH of the CO<sub>2 …
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Characterization of the VtlR regulons in Brucella abortus and Agrobacterium tumefaciens
… This transport was increased under extreme nutrient limitations and was uninhibited by the presence of other amino acids. Metabolic studies showed GABA is not utilized by B. abortus under aerobic conditions, and transcriptomic data revealed increased expression of several loci in the …
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Biosynthesis of polyhydroxyalkanoates and its medical applications
… Gram positive and Gram negative bacteria under nutrient limiting conditions. Once extracted, the PHAs exhibit a variety of properties from thermoplastic to flexible elastomeric nature. Biodegradability and bicompatibility of PHAs are also well established. Owing to these properties PHAs are …
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