Theses and Dissertations
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Item Open Access Metabolite fingerprinting of hops (Humulus lupulus) to track chemical variations(Colorado State University. Libraries, 2022) Nasiatka, Katie, author; Prenni, Jessica, advisor; Rhodes, Davina, committee member; Van Buiten, Charlene, committee memberIn the brewing industry, identification of quality crops that provide unique organoleptic properties to beer flavor (aroma, taste) are of critical importance. Hops represent a key ingredient in beer and are utilized to impart specific flavors. India Pale Ales (IPAs) are a popular style of "hoppy beers" in the U.S. and customer expectations for consistency, quality, and unique organoleptic properties of hops are growing. While the contribution of chemical compounds in hops (Humulus lupulus) such as alpha-acids (e.g. humulone) is well-understood, the influence of the hop metabolome (e.g. composition of hop chemical compounds) is still in the early stages of discovery. There is a gap in the knowledge regarding our understanding of chemistry variations in hops among cultivars and growing locations that impact the sensory quality. Traditional sensory evaluation relies on the ability to organize a group of unbiased and trained panelists, who are also subject to sensory fatigue, which can add to the challenge of this method. An alternative approach, ambient mass spectrometry (AMS) is an objective, intuitive, analytical tool capable of rapid chemical fingerprinting. The overall goal of this research is to develop a robust, high-throughput assay using AMS technology to evaluate hop quality that is reflective of both cultivar and environmental variations impacting sensory. To address this goal, twelve hop samples were sourced from three different suppliers across four different farms located in Washington and Oregon over two growing seasons. The samples included three commercial cultivars, Cascade, Centennial, and Strata. The hop samples were extracted using an 80% ethanol solution and fingerprints were acquired by Direct Analysis in Real Time Mass Spectrometry (DART-MS). The resulting data were used to train predictive models and validation was performed to evaluate classification accuracy. Additionally, authentic standards of important hop compounds (hop alpha-acids, terpenes) were used to putatively annotate DART-MS signals reflective of sensory attributes. This study demonstrates the potential of this approach for rapid evaluation of hops quality and lays groundwork for further method optimization. Ultimately, implementation of this tool could have applications for quality assurance programs and for phenotyping of hops for producers and craft brewers.Item Open Access The effects of active learning, class size, and incentives on student performance in lecture and laboratory for an introduction to animal sciences(Colorado State University. Libraries, 2019) Wesolowski, Danielle K., author; Martin, Michael J., advisor; Enns, Kellie, committee member; Clark, Nathan, committee member; Cunningham, Sam, committee memberIn the past few years there has been a notable increase in the use and interest in educational programs centered around using an instructional method known as active learning. The purpose of this study is to determine under what conditions students best perform within laboratory and lecture, while identifying learning gaps that offer potential settings to incorporate active learning. Findings showed that by placing a higher weight on attendance and participation, increases the overall student performance. Class size had little to no effect on student performance, which opens an opportunity to incorporate active learning techniques, leveraging the learning in a classroom, so that educators can spend larger amounts of time interacting with students.Item Open Access The B.C. Farmers' food donation tax credit: investigating usage among farmers' market vendors(Colorado State University. Libraries, 2019) Immell, Tara, author; Bousselot, Jennifer, advisor; Dalsted, Norman, committee member; Smith, Frank, committee memberFrom 2014 to 2016, four Canadian provinces enacted additional tax incentives targeted at farmers who donate fresh agricultural products. These tax laws are described by many as a win-win situation for farmers and people in need. The intention is to encourage farmers to donate. In British Columbia (B.C.), there is very little information released on the utilization of the tax credit. Limited research examining the efficacy of tax credits is available on the financial impacts to farmers and on the availability of fresh food to vulnerable populations. This thesis provides an overview of food donation tax credits in Canada and the United States (U.S.) and insight into tax credit utilization in B.C., taking a case study approach. Data was collected from a small sample of farmers who sell at Metro Vancouver farmers' markets and food organization managers in British Columbia, using surveys and personal interviews. Results show that B.C. farmers donate food to help people in need and are not aware of, or motivated by, the tax credit. Those not currently donating are primarily concerned about potential additional expenses, especially related to human resources and transportation. In conclusion, programs encouraging farmers to donate need to reduce the time and costs required to donate. To both increase awareness of the credit and to illustrate the financial benefit, future research should provide examples of farmers claiming this tax credit. In addition, a study to document remaining fresh agricultural products at the close of farmers' markets would further inform policymakers about potential donations.Item Open Access Investigating volunteer retention at a small, municipal public garden(Colorado State University. Libraries, 2016) Mason, Tyler, author; Irlbeck, Nancy, advisor; Graves, Leila, committee member; Wallner, Barbara, committee memberVolunteers are essential to the success of nonprofit organizations. Botanical gardens and arboreta utilize volunteers for guest services, public programs, grounds maintenance, field trips, and tours. Like other nonprofit organizations, botanical gardens face volunteer retention problems. Much psychological research has been conducted on volunteer behaviors, including factors that influence volunteer motivation, retention, and recruitment in adult 4-H volunteers leading youth educational programs. However, there is a deficiency in research focused on factors influencing volunteer retention in botanical gardens. Therefore, this mixed-methods study aims to fill that void by collecting and analyzing data gained through mailed questionnaires, field observations, and personal interviews. Triangulating these data sets revealed people are motivated to volunteer at a small, municipal public garden because they want to feel useful, enjoy learning, enjoy socializing, and want to belong to a community. Volunteers are motivated to keep coming back because they continue to learn, develop new friendships, feel a sense of accomplishment, and enjoy working with plants and people. Understanding what drives volunteers' actions provides a framework for improving the volunteer coordination program at the a small, municipal public garden.