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Browsing College of Science by Author "Aguirre, A Alonso"
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Item An Examination of the Application of Expert Elicitation and Value Tree Analysis as a Novel Decision Support Approach on an Earth Observing EnterpriseDale, Erin; Dale, Erin; Aguirre, A AlonsoThis paper analyzes a newly implemented multi-objective decision analysis (MODA) approach to assess Earth observing (EO) capabilities relied upon across the federal government. The approach develops an enterprise portfolio through value tree development with strategic and managerial input, coupled with expert elicitation at a practitioner level. The study investigates the principles of the analytic method, documents the application of the approach across federal agencies, and examines the utility and extent of the decision support analyses created from the collected data to determine the approach’s ability to support analysis and inform the decision-making of the EO enterprise. The process is found to obtain a unique breadth and depth of information in a timely manner to facilitate portfolio management from high level, multi-billion dollar budget management decisions. In addition, it provides detailed analyses of communities of use at a product level. It is underpinned by the use of proven expert elicitation techniques and subject matter expert judgment. It transparently translates a previously disconnected, vast set of knowledge into an aggregated and actionable quantitative assessment and has evolved to influence various levels of policy. It assists the National Oceanic and Atmospheric Administration (NOAA) and the United States Geological Survey’s (USGS) decision-making processes and informed the White House Office of Science and Technology Policy’s (OSTP) 2014 National Plan on Civil Earth Observations. Though expert analysts, multiple tools, and many subject matter experts are needed to create analyses for decision makers, this approach offers an effective process to define, portray, and visualize the complexity and connectedness of a large-scale technological sector, such as EO capabilities.Item Ecosystem-Condition Evaluation of the Complex, Critically-Endangered Pine Rockland Ecosystem: Indicators, Unmanned Aerial Systems (UAS), and an Emphasis on Herbaceous Ground Cover Diversity(2021) Bolen, Layne E.; Bolen, Layne E.; Aguirre, A AlonsoAn ecosystem evaluation process was applied to the critically-endangered South Florida (S FL) pine rockland (PR)(pine/grassland) ecosystem, using a) unmanned aircraft systems (UAS) surveys, and newly-developed (under-the-canopy) UAS manual flight methods; b) the synthesis of multiple data sources and types; and c) complex adaptive system (CAS) principles (redundancy, feedback loops, resiliency, alternative stable states), to identify healthy system indicators and evaluate system complexity and diversity; with the purpose of developing systematic ecosystem evaluation and reporting methods that contribute to the advancement of ecosystem protection policies, and the health assessment and conservation of global ecosystem biodiversity.Item Inhibition of Equine Spermatozoa Motility Using Sodium Tetraphenylboron and Reactivation With Caffeine-Potential to Improve Post-Thaw RecoveryHumphreys, Church; Humphreys, Church; Aguirre, A AlonsoFrozen semen provides several advantages relative to fresh or chilled semen for conservation of endangered equids. However, cryopreservation results in extensive loss of spermatozoa motility and viability arising from freeze-thaw induced membrane damage, osmotic stress, and oxidative stress leading to suboptimal fertility outcomes. The main objectives of this study were to:1) assess the ability of sodium tetraphenyl boron (TPB) to inhibit equine spermatozoa motility, 2) assess the ability of caffeine to reverse the inhibitory effects of TPB, and 3) evaluate if the inhibition of equine spermatozoa motility prior to cryopreservation improves post-thaw spermatozoa motility. Spermatozoa from domestic horse (Equus ferus caballus), Przewalski’s horse (E. f. przewalskii), and Persian onager (E. f. hemionus) were exposed to varying concentrations of TPB. Several motility characteristics including total motility, progressive motility, curvilinear motility, average path velocity, linearity, and straightness of equine spermatozoa were assessed using Computer Assisted Sperm analysis (CASA) over 2 h of in vitro incubation. After 2 h of incubation, TPB was washed and spermatozoa were resuspended in fresh medium containing 10 mM caffeine. Motility parameters described above were analyzed using CASA for 2 h of in vitro incubation. In a separate experiment, spermatozoa suspensions were pre-treated with 0 mM, 150 mM or 300 mM TPB and cryopreserved using standard protocols. Following thawing, spermatozoa were assessed for motility parameters (as described above), cell viability and acrosomal integrity. Exposure to TPB (150 mM, 300 mM and 500 mM) resulted in a significant sharp (P < 0.05) decline in total spermatozoa motility and progressive motility within 30 min of in vitro incubation. Caffeine (10 mM) failed to restore spermatozoa motility in TPB treated samples. Pre-treatment with TPB prior to cryopreservation failed to improve post-thaw sperm cell motility, progressive motility, viability or CASA parameters. However, there was no change in acrosomal integrity before or after cryopreservation. Overall, although TPB was successful in inhibiting sperm cell motility in all three subspecies of equids, contrary to earlier reports in human spermatozoa, caffeine was unable to restore motility in TPB treated spermatozoa. Furthermore, pre-treatment with TPB failed to improve post-thaw motility in equid spermatozoa. Further research is warranted to evaluate alternate cellular pathways that regulate reversible inhibition of equid spermatozoa and their effects on post-thaw sperm cell survival.Item The Genetic Variation of Peregrine Falcons (Falco peregrinus) in the Chesapeake Bay(2014-10-07) Ravinskas, Jennifer; Ravinskas, Jennifer; Aguirre, A AlonsoFor the last century, the local population of Chesapeake Bay Peregrine falcons (Falco peregrinus) has been fluctuating in its abundance, making genetic diversity difficult to assess (Johnson et al., 2010). Recently, the well-being of falcon populations in Coastal Virginia has improved, and their population numbers have been stabilizing. The extent of the Peregrine falcon genetic variation in the Chesapeake Bay population of falcons is unknown, yet the possibility of a genetic bottleneck does exist. To assess levels of allelic heterozygosity in this population, genetic analyses were performed on blood and feather samples taken from breeding pairs in the Bay during 2007 and 2013. DNA was extracted from these samples then fingerprinted at microsatellite loci with Peregrine falcon specific labeled primers (Nesje 2000b). Fingerprint results were analyzed using the GenAlEx 6.5 software, then observed alleles (AO), expected heterozygosity (HE), observed heterozygosity (HO), and fixation index (FST) were assessed. At each locus studied, there were similarities in HO between contemporary populations of falcons in the Chesapeake Bay and other global reintroduction programs in southern Scandinavia and southern Norway. At locus NVH fp54, observed heterozygosity in the Chesapeake Bay population was dramatically lower than that in the European populations. In the Chesapeake Bay population, FST values were close to zero at each locus, suggesting complete panmixis of this population. The cluster analyses performed with the STRUCTURE 2.3.4 software confirmed that the contemporary populations of Peregrine falcons in the Chesapeake Bay are genotypically one genetic cluster. Comparisons were made between the historic population of Peregrine falcons endemic to the east coast (the Appalachian mountains) and the contemporary population of birds reintroduced to and currently living in the Chesapeake Bay. These comparisons showed no significant difference when levels of observed heterozygosity, expected heterozygosity, and number of alleles were assessed. This suggests that the reintroduced population of peregrines is no more able to cope with anthropogenic or environmental disturbances than their historic counterparts. Known susceptibility of Peregrine falcons to environmental contamination as well as relatively low heterozygosity levels in the contemporary Chesapeake Bay population of Peregrine falcons suggest that continued monitoring and further conservation efforts of this population are warranted.Item The Influence of Retinoic Acid on Cell Proliferation and Differentiation in Lamb Testis TissueMolloy, Meadhbh; Molloy, Meadhbh; Aguirre, A AlonsoThe majority of wild ungulate species are threatened or endangered by extinction. Populations managed in zoos and breeding centers serve as ‘insurance’ for species sustainability and future reintroductions. However, 10-15% of animals born in ex situ collections die before reaching puberty and therefore fail to contribute to conservation breeding. Understanding the in vitro culture requirements for producing gametes from gonadal tissues could facilitate the rescue of germplasm from genetically valuable individuals. Most studies on this topic have focused on the laboratory mouse, with limited information on larger animal models. Retinoic acid (RA) is the biologically active form of vitamin A and is involved in the early steps of spermatogenesis by promoting meiosis to occur in progenitor cells. Furthermore, RA is also involved in Sertoli cell and gonocyte proliferation and/or differentiation in various species. It was hypothesized that RA would promote Sertoli cell and gonocyte proliferation and/or differentiation in testicular explants that were cryopreserved and thawed before in vitro culture. Testicular pieces (1-2 mm3) from 6-7 week-old lambs (n = 6) were cryopreserved using the slow cool method. Tissues were thawed at room temperature (1 min), then in water (25°C; 1 min), followed by three washes (5 min each) in MEM containing 20% FBS, 25 mM HEPES, and antibiotics). Thawed explants (5 pieces/treatment/week/lamb) were cultured for 5 weeks in the absence (0 μM, control) or presence (1 μM, 2 μM, and 5 μM) of RA (RA1, RA2, and RA5, respectively). Tissues were cultured on agarose blocks in MEM supplemented with 10% (v/v) FBS, sphingosine-1-phosphate (2 μM; for the first 2 weeks), insulin (2 μg/ml), transferrin (1.1 μg/ml), selenium (1 μg/ml), pyruvate (0.1 mM), glutamine (2 mM) and antibiotics. Tissues were harvested weekly to be assessed histologically and for gene expression studies. Twenty tubules of uniform size per piece were evaluated for the number of gonocytes and Sertoli cells. Tissues were analyzed for the expression of PCNA (cell proliferation), c-Kit (cell differentiation), Stra8 (synthesis of RA-responsive protein), and HSD3-β (testosterone synthesis). Analyses were performed with a linear mixed model followed by a Tukey’s test for post-hoc comparisons. Gonocyte counts changed continuously over 5 weeks of culture, and responded the most favorably to RA1 (p < 0.05). Under all treatment groups, Sertoli cell counts were maintained for the first three weeks of culture (p > 0.05), before sharply declining by week 4 (p < 0.05). In addition, Sertoli cells did not respond differently to RA1 or RA2 compared to the control (p > 0.05), but declined when treated with RA5 (p < 0.05). Both c-Kit and PCNA expression changed over 5 weeks, but PCNA was negatively impacted by RA5 (p < 0.05) while c-Kit responded positively to either RA2 or RA5 (p <0.05). Stra8 experienced dramatic changes over the culture period, and responded positively to RA1 (p < 0.05) compared to the other treatments. HSD3-β had the highest expression at week 4 before declining by week 5 (p < 0.05), but there was no effect of RA. This study demonstrates for the first time that lamb testicular explants can be 1) cultured in vitro for up to five weeks and 2) retinoic acid stimulates pathways involved in germ cell differentiation while promoting cell proliferation and steroidogenesis. Although advanced stages of spermatogenesis were not achieved in this study, results addressed critical knowledge gaps pertaining to long term culture of testicular tissue and the role of retinoic acid in lamb spermatogenesis in vitro.Item Urban Mammal Behavior AdaptationRitzel, Kate; Ritzel, Kate; Aguirre, A AlonsoAs humans continue to engineer and expand urban ecosystems, extant wildlife is increasingly exposed to novel pressures that drive changes in their spatial and temporal patterns, foraging tactics, anti-predator strategies, and other behaviors. Such behavior shifts can increase the potential for conflict with humans and present other challenges to the survival of urban species. Though behavior change in some urban taxa are widely studied, research on changing behavior in urban mammals is limited. Through systematic literature review, chapter one reveals how wild urban mammals are adjusting their behavior and explores the implications of urban-induced behavior adaptation. Chapter two seeks to address the knowledge gap on behavior change in the northern raccoon (Procyon lotor) through a comparative behavior analysis of populations in urban Washington D.C. and rural northern Virginia. Results highlight the need for long-term wildlife behavior studies across a variety of urban settings to promote successful urban wildlife management and conservation.