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Now showing 1 - 10 of 17253
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    A children's toy center in Denver, Colorado
    (Montana State University - Bozeman, 1971) Connick, Stan
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    Selecting plant species to optimize wastewater treatment in constructed wetlands
    (Montana State University - Bozeman, College of Agriculture, 2009) Taylor, Carrie Renee; Chairperson, Graduate Committee: Catherine A. Zabinski.
    Constructed wetlands are used around the world for treating domestic, agricultural, and industrial wastewater, stormwater runoff, and acid mine drainage. Plants may affect efficacy of wastewater treatment through their influence on microbial activity by creating attachment sites and releasing carbon exudates and oxygen. My research investigated seasonal plant effects on wastewater treatment by monitoring water chemistry in model subsurface wetlands planted with monocultures of 19 plant species and unplanted controls. Chemical oxygen demand (COD) removal, an indicator of water quality, declined during colder temperatures in the unplanted control, likely caused by a decrease in microbial activity. In contrast, wetlands with most plant species had constant COD removal across seasons. Redox potential and sulfate concentrations were measured as indirect measurements of the oxygenation of the wastewater. Wetlands that had a decline in COD removal during cold temperatures had constant low redox potential and sulfate concentrations throughout the seasons. Wetlands with high COD removal across seasons had elevated redox potentials and sulfate concentrations during the winter, indicating elevated oxygen availability, which may offset the negative temperature effect on microbial processes. I measured root oxygen loss (ROL) in the summer and the winter to determine whether oxygen release was sufficient to influence wastewater treatment and cause seasonal and species-specific effects on water chemistry. COD removal and ROL were positively correlated at 4°C but not at 24°C; however, the amount of root oxygen release only accounted for a portion of the required oxygen to facilitate plant's influence on COD removal. Flooding tolerance was quantified for each species by comparing plants' biomass between flooded and drained conditions. Plants' botanical grouping, Wetland Indicator Status, and flooding tolerance were compared to plants' influences on wastewater treatment to determine whether easily measured plant traits can be used to identify plants that will optimize wastewater treatment. All the sedges and rushes, obligate wetlands species, and 8 of 9 flood-tolerant plants had greater COD removal than the control at 4°C, the coldest temperature incubation. These results can be applied for wetland design by selecting plant species to optimize wastewater treatment, especially in cold climates.
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    Using the penalty immersed boundary method to model the interaction between filiform hairs of crickets
    (Montana State University - Bozeman, College of Engineering, 2011) Gordon, Eric Duane; Chairperson, Graduate Committee: Jeffrey Heys
    Fluid-structure interactions are important in a wide range of applications and, due to their complexity, need extensive experimental and computational research. One such example comes from crickets, which have evolutionarily developed an excellent micro-air-flow sensory system. Understanding principles of the cricket' micro-air-flow sensor will help design and manufacture artificial sensors. This thesis focuses on improving and validating a Penalty Immersed Boundary (PIB) model of the cricket sensory system, which consists of hundreds of filiform hairs. Previous efforts by others have modeled the filiform hair as a rigid inverted pendulum. Advantages to the PIB approach over previous models include a flexible fluid solver (previous models used an idealized, analytical flow field), the filiform hairs are not required to be completely rigid, and, most importantly, the entire cerci and all the filiform hairs can be modeled. The first goal was to improve the precision and accuracy of modeling a single filiform hair by adjusting model parameters so that the model predictions more accurately fit experimental data. A second goal was to model a portion of a full cercus based on filiform hair data from a real cricket and use the model to determine the interactions occurring between multiple hairs and identify any evolutionary optimization of the cercal system.
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    Comparisons of phenological variability and precipitation of ecoregion and grassland cover types in the northern Great Plains from 1988 to 1993
    (Montana State University - Bozeman, College of Letters & Science, 1999) Gillett, Linda E.
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    TrkB/BDNF signalling patterns the sympathetic nervous system
    (2015-09) Kasemeier-Kulesa, Jennifer S.; Morrison, Jason A.; Lefcort, Frances; Kulesa, Paul M.
    The sympathetic nervous system is essential for maintaining mammalian homeostasis. How this intricately connected network, composed of preganglionic neurons that reside in the spinal cord and post-ganglionic neurons that comprise a chain of vertebral sympathetic ganglia, arises developmentally is incompletely understood. This problem is especially complex given the vertebral chain of sympathetic ganglia derive secondarily from the dorsal migration of ‘primary’ sympathetic ganglia that are initially located several hundred microns ventrally from their future pre-synaptic partners. Here we report that the dorsal migration of discrete ganglia is not a simple migration of individual cells but a much more carefully choreographed process that is mediated by extensive interactions of pre-and post-ganglionic neurons. Dorsal migration does not occur in the absence of contact with preganglionic axons, and this is mediated by BDNF/TrkB signalling. Thus BDNF released by preganglionic axons acts chemotactically on TrkB-positive sympathetic neurons, to pattern the developing peripheral nervous system.
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    Transitory leaf starch is an important determinant of plant yield
    (Montana State University - Bozeman, College of Agriculture, 2011) Schlosser, Alanna Jane; Chairperson, Graduate Committee: Michael J. Giroux.
    Efficient allocation of photoassimilates from source to sink tissues is important for optimal plant growth and yield as relative source and sink strength drives growth potential of plant organs. A common method aimed at improving plant yield has been to modify enzymes important to storage compound biosynthesis in sink tissues such as seeds. As the rate limiting step in starch biosynthesis, ADP-glucose pyrophosphorylase (AGPase) has received much attention in this regard. Previously, overexpression of AGPase in seeds resulted in an enhanced yield phenotype in which both plant yield and biomass were increased. However, yield advantages were only observed under nonlimiting environmental resources. The objective of these studies was to 1) determine the importance of native leaf starch levels to the productivity and growth of maize and 2) target source strength by overexpressing AGPase in rice leaves. To determine the importance of native leaf starch levels in maize, field trials of BC 4F 2:3 plants segregating for the presence or absence of the agps-m1 mutation and leaf starch were conducted in Citra, Florida. The results clearly demonstrate the importance of normal leaf starch levels to maize productivity. The starchless agps-m1 plants were 6 to 13 cm shorter, flowered 2 to 3 days later, and had 30 percent lower seed yield than their wild type sisterlines. The impact of increased AGPase in rice leaves was then tested by overexpressing AGPase in rice leaves. Two expression constructs were used to transform rice cultivar Nipponbare, each containing a modified form of the maize endosperm AGPase large subunit sequence, Sh2r6hs, as well as the small subunit sequence, Bt2. Expression of the transgenes was under control of either the rice leaf AGPase small subunit promoter, Ags1, or native rice RuBisCO small subunit promoter, RBC. Expression of the transgenes under the RBC promoter is associated with significantly increased plant biomass. Our results indicate that it is possible to increase plant yield without increasing the rate of photosynthesis. Further, it indicates the possibility of manipulating plant yield through increasing AGPase activity in leaf tissue.
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    A branch-and-bound algorithm for the crossing number of a graph
    (Montana State University - Bozeman, College of Engineering, 2000) Tan, Zheng
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    Whispering Swan : a gallery and residential complex
    (Montana State University - Bozeman, 1989) Slezak, Sherry K.; Chairperson, Graduate Committee: Pamela Jean Bancroft
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    Harvesting far-red light: Functional integration of chlorophyll f into Photosystem I complexes of Synechococcus sp. PCC 7002
    (2020-08) Tros, Martijn; Bersanini, Luca; Shen, Gaozhong; Ho, Ming-Yang; van Stokkum, Ivo H. M.; Bryant, Donald A.; Croce, Roberta
    The heterologous expression of the far-red absorbing chlorophyll (Chl) f in organisms that do not synthesize this pigment has been suggested as a viable solution to expand the solar spectrum that drives oxygenic photosynthesis. In this study, we investigate the functional binding of Chl f to the Photosystem I (PSI) of the cyanobacterium Synechococcus 7002, which has been engineered to express the Chl f synthase gene. By optimizing growth light conditions, one-to-four Chl f pigments were found in the complexes. By using a range of spectroscopic techniques, isolated PSI trimeric complexes were investigated to determine how the insertion of Chl f affects excitation energy transfer and trapping efficiency. The results show that the Chls f are functionally connected to the reaction center of the PSI complex and their presence does not change the overall pigment organization of the complex. Chl f substitutes Chl a (but not the Chl a red forms) while maintaining efficient energy transfer within the PSI complex. At the same time, the introduction of Chl f extends the photosynthetically active radiation of the new hybrid PSI complexes up to 750 nm, which is advantageous in far-red light enriched environments. These conclusions provide insights to engineer the photosynthetic machinery of crops to include Chl f and therefore increase the light-harvesting capability of photosynthesis.
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    Empowering health education : a conceptual framework and an instrument for assessing health professionals' use of empowering strategies
    (Montana State University - Bozeman, College of Education, Health & Human Development, 1992) Paul, Lynn Carol
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