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 54 for “"Photosynthetically active radiation"”.
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Quantifying the impact of remotely sensed photosynthetically active radiation retrievals on empirical crop models in the United States
Photosynthetically active radiation (PAR), is an essential component for life onEarth and one of the essential climate variables. Due to the differences in biochemistry, cell structure, and photosynthetic pathways, different plant species absorb PAR with varying efficiency and have evolved to …
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A tripartite study on Bayesian estimation of photosynthetically active radiation, impacts of future climate, and adaptation strategies on crop production: a spatial model framework for the Eastern Kansas River Basin
… in process-based crop model inputs such as photosynthetically active radiation (PAR) is essential to enhance model accuracy, while also documenting new estimation methods. The ultimate goal of this dissertation is to develop climate change adaptation strategies for rainfed and irrigated …
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Modelling Stream Metabolism and Fish Biomass in Headwater Streams of the Eastern Cascades Mountains
… owing in part to extremely limiting levels of photosynthetically active radiation and dissolved inorganic nitrogen, and the air water gas-exchange estimations were likely inaccurate. Metabolism metrics and trout biomass did not relate with photosynthetically active radiation, dissolved …
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Effect of plant density on soybean seed yield and quality
… which in turn was a function of the amount of photosynthetically active radiation (PAR) intercepted by the canopy. A green area index (GAI) of 3.4-3.6 was required to attain canopy closure interception of >95% incoming photosynthetically active radiation). Seed yield was also strongly related …
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Corticular Photosynthetic Dynamics for a Coastal Evergreen Shrub: Myrica Cerifera
… Variations in % refixation paralleled changes in photosynthetically active radiation (PAR). As light attenuated with increasing branch order % refixation decreased. Increased PAR in the winter due to a more sparse canopy lead to increases in % refixation. Total chlorophyll content and chlorophyll …
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Variability within the 10-year pollen rain of a seasonal neotropical forest
… effect of the current year’s temperature and photosynthetically active radiation (PAR). Our results demonstrate the relative stability of the long-term pollen rain as a larger regional signal of flowering response to climatic variability, while also suggesting that paleoecological …
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Prescribed Fire Effects on Woodland Structure, Light Levels and Understory Plant Communities in Missouri Oak-Hickory Woodlands
… between canopy closure and transmittance of photosynthetically active radiation. In addition, both of these variables were positively correlated with species richness and Shannon's diversity index.
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Quantifying pelagic primary production and respiration via an automated in-situ incubation system
… ocean and in shallow aquatic ecosystems where photosynthetically active radiation (PAR) is abundant. However, the dynamic nature and large degree of heterogeneity in these ecosystems pose substantial challenges for providing accurate estimates of marine primary production and metabolic state. …
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Establishment of native plant species for livestock forage in silvopasture systems
… how differences in environmental factors (Photosynthetically Active Radiation (PAR), ambient temperature, and soil moisture) associated with each treatment affect establishment of native plant species. The experiment was a Randomized Complete Block Design replicated in 2020 and 2021. …
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Forage Production and Nutritive Value in a Temperate Appalachian Silvopasture
… forage canopy temperature, soil moisture, and photosynthetically active radiation were measured to determine forage responses to field treatments as functions of resource allocation. Tree density had the greatest effect on forage production and nutritive value. Across both years, yields were …
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Context-dependent controls of periphyton across the littoral-benthic habitat of deep, clear lakes
… (NDS), water column nutrient data, and photosynthetically active radiation (PAR) measurements. We observed that periphyton nutrient limitation and inhibition vary with depth and habitat. Differences were primarily driven by the concentration of dissolved inorganic nitrogen (DIN) and the …
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Spatial and temporal dynamics of the terrestrial carbon cycle : assimilation of two decades of optical satellite data into a process-based global vegetation model
… of global AVHRR-fPAR data (fPAR – fraction of photosynthetically active radiation). Assimilation of the satellite data into the model allows improved simulations of carbon fluxes on global as well as on regional scales. As it is based on observed data and includes agricultural regions, the …
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Effect of Crude Oil on Light Attenuation and the Resulting Impacts on Marine Microbial Phototrophs and Heterotrophs
… attenuates the shorter wavelengths of photosynthetically active radiation. Therefore, we proposed that this change in the spectrum and reduction in light intensity would affect microbial phototrophic community composition, which in turn would alter the heterotrophic community and …
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Light utilization and excretion of organic matter by antarctic lake phytoplankton
… were efficient at trapping the low levels of photosynthetically active radiation present in these dimly lit lakes, while ε indicate that environmental conditions of these lakes are limiting their respective phytoplankton communities. Percent extracellular release (PER) of organic matter was …
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Seasonal and Spatial Variation in Leaf Area Index, Litter Production, and Light Levels in Myrica Cerifera,Shrub Thickets Across a Barrier Island Chronsequence
… LAI-2000) and three times by measurement of photosynthetically active radiation (PAR) and use of the Beer-Larnbert law. Leaf area index was also estimated through leaf litter collection and use of allometric relationships between stem diameter and leaf area. The oldest of the four thickets …
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The potential application of variable renewable energy supplies to increase the horticultural productivity of the Isle of Lewis, Scotland.
… on Lewis was characterised. The mean ratio of photosynthetically active radiation (PAR) to solar radiation (SR) (fE) recorded in 2010 was 0.458. fE was found to be significantly different between the first and last hour of daylight and 12:00 GMT (F, (2, 33) = 7.98, p<0.001) and between winter …
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Heterosis in a broad range of alfalfa germplasm
… caused genotypes from climates with low June photosynthetically active radiation to create better yielding and more heterotic sativa-falcata hybrids. Improved morphology was not correlated with heterosis, but was correlated with improved biomass yield. However, it was observed that visually …
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The effect of non-glaucousness, as conferred by Inhibitor of Wax 1, on physiology and yield of UK Wheat
… properties, were measured. Iw1 reduced flag leaf photosynthetically active radiation (PAR) reflectance by 15-40% and canopy reflectance by 12-20% (p<0.05). Despite this, Iw1 did not affect flag leaf PAR absorbance or canopy temperature, and conferred no advantage under long-term shading. …
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Ecological Effects of Overwater Structures on Subtidal Kelp, Northern Puget Sound, Washington
… of 2017 for subtidal kelp distribution, biomass, photosynthetically active radiation (PAR), substrate, and fish presence. Georeferenced benthic video surveys were conducted along parallel transects to create 1 m grid cell maps encoded for subtidal kelp presence/absence at each site. Wet biomass …
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Multi-scale Remote Assessment of Phenology of Photosynthesis and Productivity of Northern Forests
… be good indicators of the fraction of absorbed photosynthetically active radiation (ƒAPAR) and photosynthetic efficiency (ɛ), respectively. CCI was revealed to be a good indicator of both photosynthesis and ɛ. Finally, I parameterized a light-use efficiency (LUE) model with PRI and CCI as …
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