College of Agriculture & Natural Resources
Permanent URI for this communityhttp://hdl.handle.net/1903/1598
The collections in this community comprise faculty research works, as well as graduate theses and dissertations.
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Item Understanding Conservationists' Perspectives Concerning the Ethical Dilemmas Associated with Declines in African Vulture Populations(2018) Yee, Natalie; Harrell, Reginal M; Environmental Science and Technology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Several African vulture populations are declining due to anthropogenic causes. This research explored viewpoints of conservationists to identify ethical dilemmas and extrapolate potential solutions that balance the needs of African vultures and the welfare of impacted societies. The methodology consisted of two parts: A Q-Methodology activity and a semi-structured interview. The Q-Methodology activity used statements in a ranked system to discover what the participants prioritized. The semi-structured interview allowed for an in-depth understanding as to why the respondents ranked the statements as they did. These steps addressed not only what the subjects believed, but why they believed it, a key element in uncovering the ethical standpoints of the respondents. One major finding demonstrated that overall, participants held a deontological (duty-driven) viewpoint that fuels them to pursue conservation work. Exploring views of conservationists familiar with the African vulture declines is the first step to creating ethical policies to save the vultures.Item Investigation of spermatozoal metabolism and substrate utilization in domestic and non-domestic felids(2015) Weiner, Halli Sigal; Keefer, Carol L; Animal Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Cryopreservation of spermatozoa is a critical aspect of assisted reproduction. However in most cases, this process causes diminished spermatozoal function and low cellular survival. The effects of cryopreservation are further compounded in spermatozoa from individuals with disorders known to affect fertility. Teratospermia, characterized by the ejaculation of >60% morphologically abnormal spermatozoa, is one such disorder. Sperm from individuals with this condition exhibit reduced motility, impaired mitochondrial function, and a reduced ability to bind, penetrate, and fertilize an oocyte compared to sperm from normospermic males. Interestingly, even spermatozoa from teratospermic males that appear normal exhibit reduced functional capacity and following cryopreservation all cells are further impaired. More than 90% of felid species are affected by this condition, and it is prevalent among humans. Previous research suggested that impaired sperm metabolism in cheetahs – a ubiquitously teratospermic species – contributes to their poor cryosurvival and function, but the specific mechanisms are unknown. In this research, we hypothesized that inherent differences exist between the substrates and metabolic pathways utilized by sperm from normospermic and teratospermic individuals and on a species-specific basis. Gas chromatography - mass spectrometry (GC-MS) was used to investigate felid sperm metabolism using semen collected from domestic cats (Felis catus), cheetahs (Acinonyx jubatus), and clouded leopards (Neofelis nebulosa). The main objectives of this research were to: 1) characterize the metabolome of spermatozoa and seminal fluid; 2) investigate the role of β-oxidation in sperm motility and metabolism; and 3) interrogate the significance of specific metabolic pathways using metabolic activity profiling and heavy isotope tracers. Using GC-MS enabled the identification of metabolites which were unique to each species and sperm status (normospermic vs. teratospermic). Additionally, treatment of sperm with a β-oxidation inhibitor caused impaired motility in cheetah - but not domestic cat or clouded leopard - spermatozoa. Finally, fluxomic analysis demonstrated that glucose, fructose, and pyruvate are metabolized by felid sperm, but pathway utilization is species-specific. This is the first study to utilize a metabolomic and fluxomic approach to studying felid sperm, and the results of these studies illustrate the complexity of sperm metabolism on a species-specific basis. Understanding metabolic pathway activity in these cells will aid in the development of improved assisted reproduction techniques that may better facilitate sperm function and survival.Item Greenway as the Framework for Community Design on the Patapsco River Valley(2014) Britt, Nancy Fruchter; Kweon, Byoung-Suk; Plant Science and Landscape Architecture (PSLA); Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)By the nature of their shared locality, greenway corridors and the communities along them share a unique set of socio-cultural and ecological resources that are rooted in the greenway's landscape form and character. When unified, greenways and surrounding communities foster a sense place that is deeply site specific. This thesis explores the unique characteristics of greenway landscapes, using them as a basis for formulating cohesive design criteria for creating vibrant greenway-adjacent communities. These criteria offer solutions for balancing growth and conservation strategies to guide community design within the framework of the greenway, achieve community and greenway sustainability, and support the integrity of the landscape. Using a site along Maryland's Patapsco River Valley, this thesis demonstrates how these criteria can work towards achieving an ideal community form where design highlights unique site features to create awareness of and support for the greenway context.Item Best Management Practice Use and Nutrient Management in Maryland: A 2010 Snapshot(2010-01-01) Lichtenberg, Erik; Parker, Doug; Lane, Sarah