2023 MU Theses - Freely available online
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Item Spring establishment of tall fescue utilizing sunn hemp as a companion crop under rotational grazing management(University of Missouri--Columbia, 2023) Brandl, Chrisee Sue; Naumann, Harley[EMBARGOED UNTIL 12/01/2024] Tall fescue (Schedonorus arundinaceus (Schreb.) Dumort.) is the predominant perennial cool season grass used for forage in Missouri. It demonstrates a bi-modal seasonal yield distribution with forage production periods observed in the spring and fall and a lack of forage production in the summer and winter months. Establishing tall fescue as part of a total renovation or a partial renovation of existing pastures is recommended to be performed in the fall rather than the spring due to more desirable environmental conditions and the ability to establish roots prior to subsequent spring growth. However, spring establishment of tall fescue may be desirable as management opportunities arise. Introducing warm season annual legumes, such as sunn hemp (SH, Crotalaria juncea L.), may improve summer forage productivity, mitigating the summer slump as well as serving as a companion crop during spring tall fescue establishment. We hypothesized that the inclusion of SH in combination with spring planted tall fescue would benefit tall fescue establishment the subsequent spring while providing grazeable forage throughout the growing season. The objectives of this study were to 1. evaluate the effects of SH seeding rate and grazing on subsequent spring tall fescue plant density and 2. evaluate the effects of SH seeding rate, grazing, and seasonal productivity on herbage accumulation and forage nutritive value. The experiment was a split block design in the years 2020 and 2021; Whole-plots were assigned SH seeding rates 0, 11, 22, and 34 kg ha-1) and sub plots were assigned as GRAZED and NON-GRAZED treatments. There were 4 GRAZED replications and 4 NON-GRAZED replications. Differences were considered significant at P ≤ 0.05 and data regressions were considered significant at P ≤ 0.1. Sunn hemp was separated from all other pasture plant species that will be referred to as other grasses and forbs henceforth. Tall fescue spring establishment was greatest at 0 and 22 kg ha-1 SH seeding rates and grazing resulted in greater TF plant density than non-grazed treatments. Soil test results revealed that ammonium increased in the subsequent spring. In contrast to ammonium, the cation exchange capacity and magnesium decreased in the subsequent spring. Sunn hemp herbage accumulation was greatest at 22 and 34 kg ha-1 SH seeding rates and 120 days after planting (DAP) in grazed treatments. In contrast to SH herbage accumulation, other grasses and forbs herbage accumulation declined at greater SH seeding rates with grazing imposed. Crude protein (CP) concentrations increased in other grasses and forbs as SH seeding rate increased with and without grazing. Sunn hemp neutral detergent fiber digestibility (NDFD), in-vitro true digestibility (IVTD), and CP concentrations were greater in grazed treatments compared to non-grazed treatments. Other grasses and forbs digestible neutral detergent fiber (dNDF) concentrations were greater in the non-grazed treatments compared to the grazed treatments. With grazing imposed, other grasses and forbs neutral detergent fiber (NDF), NDFD, dNDF, IVTD, and CP concentrations decreased with DAP. Without grazing, other grasses and forbs NDF and acid detergent fiber (ADF) concentrations increased with DAP whereas NDFD and IVTD concentrations decreased with DAP. With grazing imposed, SH NDF concentrations increased with DAP whereas IVTD and CP concentrations decreased with DAP. Without grazing, SH NDF and ADF concentrations without grazing increased with DAP whereas NDFD, IVTD, and CP concentrations decreased with DAP. Sunn hemp plant density decreased with DAP and increased as SH seeding rate increased with the greatest plant density at the 34 kg ha-1 seeding rate with grazing imposed and in NON-GRAZED treatments. Sunn hemp plant density was greater in the NON-GRAZED treatments compared to the GRAZED. A positive correlation was observed for soil temperature and SH herbage accumulation and SH plant density such that soil temperature increased as SH herbage accumulation and SH plant density increased. A negative correlation was observed for photosynthetically active radiation (PAR) and SH herbage accumulation such that PAR decreased as SH herbage accumulation increased. Sunn hemp plant density and SH herbage accumulation in NON- GRAZED treatments were positively correlated. Sunn hemp herbage accumulation increased as SH plant density increased. A negative correlation was observed for TF plant density and seasonal herbage accumulation of all pasture plant species such that TF plant density decreased as seasonal herbage accumulation increased. Our data suggest that the combination of SH and grazing can benefit spring planted TF establishment. Sunn hemp herbage accumulation increased significantly with rate and DAP providing greater amounts of grazeable forage during the summer months. Other grasses and forbs herbage accumulation decreased significantly with greater SH seeding rates, suggesting that SH can reduce competition from other plant species. The increase in ammonium the subsequent spring suggests that animal excreta from grazing and plant residues were beneficial to the persistence of TF planted in our study. Based on correlations of environmental factors and SH herbage accumulation, grazing can potentially alter the canopies microclimate to lower soil temperature and increase PAR through the removal of vegetation. In summary, the inclusion of SH at any seeding rate and the application of grazing is a promising practice to benefit spring planted TF establishment.Item A review of the use of escape extinction for the reduction of inappropriate mealtime behavior(University of Missouri--Columbia, 2023) Maddox, Grace; Dotson, WesleyFood selectivity and inappropriate mealtime behaviors (IMB) can disrupt a child’s ability to consume the necessary calories and nutrients necessary for growth and development. This literature review examined whether escape extinction was a necessary treatment component for the treatment of IMB. Studies were included in the review if (a) the primary and secondary dependent variables were IMB or a behavior that is topologically equivalent (e.g., food refusal) and acceptance of solid food or liquids, and (b) the study compares an intervention utilizing escape extinction to an intervention that does not utilize escape extinction or an intervention that uses a different form of escape extinction. Studies were evaluated based on the following variables: types of treatment evaluated, most effective treatment, inclusion of a functional analysis, intervention setting, interventionist, and the inclusion of social validity measures. For all participants but one, some form of escape extinction was necessary to reduce IMB and increase food acceptance.Item High-intensity ultrasound-assisted alkaline extraction of soy protein : optimization, modeling, physicochemical and functional properties(University of Missouri--Columbia, 2023) Zhang, Wenxue; Vardhanabhuti, BongkoshSoybeans, classified within the legume family, have a historical legacy as a dietary staple across diverse cultures. Preferred due to their elevated protein content, versatility, and numerous health advantages, soybeans are a prominent source of plant-derived protein. They manifest in various forms, including whole beans, soybean oil, tofu, tempeh, soy milk, and a panoply of soy-based offerings. Relevant data underscores soybeans' protein composition, approximating around 40 percent. Currently, soybean protein extraction methods encompass a range of techniques such as freeze-thaw, ultra-high-pressure homogenization, alkali-soluble acid precipitation, microwave-assisted extraction, and subcritical water extraction. Nonetheless, these approaches frequently obtain suboptimal protein yields, undermine protein structural integrity, entail protracted processing time, incur elevated expenses and present formidable hurdles to industrial production. Based on these backgrounds, this research endeavors to establish a high-efficiency preparative protocol utilizing ultrasonic-assisted extraction for soy protein recovery. Meanwhile, it aims to systematically probe the protein's structural and functional properties, fostering a robust theoretical framework and empirical groundwork for the further advancement of soy protein resources. A synergistic approach integrating the Plackett-Burman design (PBD) and the Box- Behnken design (BBD) was employed to optimize the high-intensity ultrasound-assisted extraction (HUAE) process for soy protein. The PBD effectively pinpointed influential factors, while the BBD concurrently assessed interrelated responses: the yield of protein and the energy expenditure. Both aspects are pivotal in achieving optimal and resource- efficient protein extraction. From the PBD outcomes, four crucial parameters (liquid-to- solid ratio, temperature, ultrasonic amplitude, and extraction time) were meticulously considered for subsequent optimization endeavors. The response prediction was accurately tailored to the experimental conditions by employing a well-matched second-order polynomial model. The BBD findings unveiled the optimum conditions for HUAE of soy protein: a liquid-solid ratio concentration of 50:1 mL/g, a temperature of 50 degreesC, an ultrasonic amplitude of 48 percent, and an extraction time of 10 minutes. These optimized conditions yielded an actual extraction rate of 34.45 percent. Notably, compared to the conventional alkaline water extraction technique, the high-intensity ultrasound-assisted method substantially augmented the protein extraction rate (by approximately 33.69 percent) and remarkably shortened the protein extraction time from 60 minutes to 10 minutes. Furthermore, an exploration into the dissimilarity between the physicochemical and functional properties of soy protein garnered through the high-intensity ultrasound-assisted extraction method and the conventional extraction approach was undertaken. The findings indicated that soy protein extracted via ultrasonic treatment exhibited a more flexible molecular structure, accompanied by an augmentation in hydrophobic groups. This molecular adaptation translated to superior emulsion properties and increased antioxidant properties. Hence, when assessing the economic and environmental ramifications, it is deducible that ultrasonic-assisted alkaline extraction is an efficacious soy protein extraction method. This method not only yields protein with enhanced structural properties but also yields more potent antioxidant capacities, all achieved within 10 minutes and with diminished energy consumption (from the desirability response function). Nevertheless, it is noteworthy that the solubility of soy protein treated by ultrasound witnessed a considerable reduction in contrast to the control. This diminishing solubility may potentially confine the widespread utilization of the protein within the expansive realm of the food industry. The outcomes of this investigation furnish valuable insights into the judicious selection of optimal high-intensity ultrasound-assisted extraction parameters for soy protein, thereby paving the way for its broader integration and application within the food industry.Item An examination of the portrayal of homelessness and the opioid crisis in US and Canadian newspapers(University of Missouri--Columbia, 2023) Yorke, Ekua; Renoe, Susan D.This research examines how homelessness and the opioid crisis were portrayed from 2018 to 2023 by one US and one Canadian newspaper. The thesis traces qualitative changes in the occurrence of keywords and topics over six years in two newspapers, The Seattle Times and The Vancouver Sun. The data shows prevalence of thematic framing and a shift towards narrative journalism both in The Vancouver Sun and The Seattle Times. The highest use of thematic framing coincided with the onset of the COVID-19 pandemic. The rise in the use of episodic framing appears to coincide with the increase in opioid related fatalities among the homeless population. Over the six years of study, an increasing number of articles started to use personal narratives to discuss the issues of homelessness and the opioid crisis, likely as an attempt to increase attention and empathy for these issues. Study findings highlight how newspapers can influence the public's understanding on the complex issues of homelessness and the opioid crisis.Item A defense of the relational account of morality(University of Missouri--Columbia, 2023) Tiwari, Alok; Johnson, Robert N.In this essay I shall defend the thesis that morality is an intrinsically relational normative domain constituted by relational claims and corresponding directed duties. On the relational approach to morality, moral considerations are requirements on one's agency that are grounded in the claims that particular others have against the agent. My central thesis is that all moral obligations are directed duties: an agent A has a moral obligation to do X if and only if A owes a duty to some patient B to do X. Moral wrongs, it follows, always wrong someone.