Matching Items (6)
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- All Subjects: Environmental science
- Creators: Grimm, Nancy
- Creators: Penton, Christopher
- Status: Published
Description
Sexually transmitted diseases like gonorrhea and chlamydia, standardly treated with antibiotics, produce over 1.2 million cases annually in the emergency department (Jenkins et al., 2013). To determine a need for antibiotics, hospital labs utilize bacterial cultures to isolate and identify possible pathogens. Unfortunately, this technique can take up to 72 hours, leading to several physicians presumptively treating patients based solely on history and physical presentation. With vague standards for diagnosis and a high percentage of asymptomatic carriers, several patients undergo two scenarios; over- or under-treatment. These two scenarios can lead to consequences like unnecessary exposure to antibiotics and development of secondary conditions (for example: pelvic inflammatory disease, infertility, etc.). This presents a need for a laboratory technique that can provide reliable results in an efficient matter. The viability of DNA-based chip targeted for C. trachomatis, N. gonorrhoeae, and other pathogens of interest were evaluated. The DNA-based chip presented several advantages as it can be easily integrated as a routine test given the process is already well-known, is customizable and able to target multiple pathogens within a single test and has the potential to return results within a few hours as opposed to days. As such, implementation of a DNA-based chip as a diagnostic tool is a timely and potentially impactful investigation.
ContributorsCharoenmins, Patherica (Author) / Penton, Christopher (Thesis director) / Moore, Marianne (Committee member) / College of Integrative Sciences and Arts (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
Description
Precision agriculture (PA) integrating information technology arouses broad interests and has been extensively studied to increase crop production and quality. Sensor probe technology, as one of the PA technologies, provides people with accurate real-time data, which has become an essential part of precision agriculture. Herein a novel microbial sensor probe (MiProbE) is applied to monitor and study the growth of tomatoes (Solanum lycopersicum L.) in real-time at germination and seedling stages. The result showed the raw Miprobe signals present day/night cycles. Alginate-coated probes effectively avoided signal response failure and were more sensitive to the treatments than uncoated probes. The probe signals from successfully germinated tomato seeds and non-germinated seeds were different, and the signal curve of the probe was closely related to the growth conditions of tomato seedlings. Specifically, the rising period of the probe signals coincided with the normal growth period of tomato seedlings. All probes exhibited sudden increases in signal strength after nutrient treatments; however, subsequent probe signals behaved differently: algae extract-treated probe signals maintained a high strength after the treatments; chemical fertilizer-treated probe signals decreased earlier after the treatments; chemical fertilizers and algae extract-treated probe signals also maintained a higher strength after the treatments. Moreover, the relationship between ash-free dry weight and the signal curve indicated that the signal strength positively correlates with the dry weight, although other biological activities can affect the probe signal at the same time. Further study is still needed to investigate the relationship between plant biomass and Miprobe signal.
ContributorsQi, Deyang (Author) / Weiss, Taylor (Thesis advisor) / Penton, Christopher (Committee member) / Park, Yujin (Committee member) / Arizona State University (Publisher)
Created2021
Description
Climate change is one of the most pressing issues facing humanity, and cities are likely to experience many of the most dangerous effects of climate change. One way that cities aim to adapt to become more resilient to climate change is through the provision of locally produced ecosystem services: the benefits that people get from nature. In cities, these ecosystem services are provided by diverse forms of urban ecological infrastructure (UEI): all parts of a city that include ecological structure and function. While there is a growing body of research touting the multifunctionality of UEI and an increasing number of cities implementing UEI plans, there remain important gaps in understanding how UEI features perform at providing ecosystem services and how the local social-ecological-technological context affects the efficacy of UEI solutions. Inspired by the need for cities to adapt to become more resilient to climate change, this dissertation takes an interdisciplinary approach to understand how diverse UEI features and their ecosystem services are perceived, provided, and prioritized for current and future climate resilience. The second chapter explores how a diverse group of local actors in Valdivia, Chile perceives the city’s urban wetlands and identifies common trade-offs in the perceived importance of different ecosystem services from the wetlands. The third chapter demonstrates species-level differences and trade-offs between common street trees in Phoenix, Arizona in their ability to provide the ecosystem services of both local climate regulation and stormwater regulation. The fourth chapter compares how participatory scenarios from nine cities across the United States and Latin America vary in the degree to which they incorporate UEI and ecosystem services into future visions. The fifth chapter returns focus to Phoenix and illustrates dominant perspectives on the prioritization of ecosystem services for achieving climate resilience and how those priorities change across temporal scales. The dissertation concludes with a synthesis of the previous chapters and suggestions for future urban ecosystem services research. Combined, this dissertation advances understanding of ecosystem services from UEI and highlights the importance of considering trade-offs among UEI features in order help achieve more just, verdant, and resilient urban futures.
ContributorsElser, Stephen Robert (Author) / Grimm, Nancy (Thesis advisor) / Berbés-Blázquez, Marta (Committee member) / Cook, Elizabeth (Committee member) / McPhillips, Lauren (Committee member) / York, Abigail (Committee member) / Arizona State University (Publisher)
Created2022
Description
Spatial and temporal patterns of biodiversity are shaped, in part, by the resources available to biota, the efficiency of resource transfer through the food web, and variation in environmental conditions. Stream and riparian zones are dynamic systems connected through reciprocal resource exchange and shaped by floods, droughts, and long-term patterns in the quantity, timing, and variability of streamflow (flow regime). The interdependent nature of the stream-riparian ecosystem defies the scope of any single discipline, requiring novel approaches to untangle the controls on ecological processes. In this dissertation, I explored multiple mechanisms through which streamflow and energy flow pathways maintain the community and trophic dynamics of desert stream and riparian food webs. I conducted seasonal sampling of Arizona streams on a gradient of flow regime variability to capture fluctuations in aquatic communities and ecosystem production. I found that flow regime shapes fish community structure and the trajectory of community response following short-term flow events by constraining the life history traits of communities, which fluctuate in prevalence following discrete events. Streamflow may additionally constrain the efficiency of energy flow from primary producers to consumers. I estimated annual food web efficiency and found that efficiency decreased with higher temperature and more variable flow regime. Surprisingly, fish production was not related to the rate of aquatic primary production. To understand the origin of resources supporting aquatic and riparian food webs, I studied the contribution of aquatic and terrestrial primary production to consumers in both habitats. I demonstrated that emergent insects “recycled” terrestrial primary production back to the riparian zone, reducing the proportion of aquatic primary production in emergent insect biomass and riparian predator diet. To expand the concept of stream and riparian zones as an integrated ecosystem connected by resource cycling through the food web, I introduced a quantitative framework describing reciprocal interconnections across spatial boundaries and demonstrated strong aquatic-riparian interdependencies along an Arizona river. In this dissertation, I develop a novel perspective on the stream-riparian ecosystem as an intertwined food web, which may be vulnerable to unforeseen impacts of global change if not considered in the context of streamflow and resource dynamics.
ContributorsBaruch, Ethan Max (Author) / Sabo, John (Thesis advisor) / Bateman, Heather (Committee member) / Cease, Arianne (Committee member) / Grimm, Nancy (Committee member) / Arizona State University (Publisher)
Created2021
Assessing the Response of Macroinvertebrate Communities to River Flow Dynamics in the Sonoran Desert
Description
Climate change is causing hydrologic intensification globally by increasing both the frequency and magnitude of floods and droughts. While environmental variation is a key regulator at all levels of ecological organization, such changes to the hydrological cycle that are beyond the normal range of variability can have strong impacts on stream and riparian ecosystems within sensitive landscapes, such as the American Southwest. The main objective of this study was to investigate how anomalous hydrologic variability influences macroinvertebrate communities in desert streams. I studied seasonal changes in aquatic macroinvertebrate abundances in eleven streams that encompass a hydrologic gradient across Arizona’s Sonoran Desert. This analysis was coupled with the quantification and assessment of stochastic hydrology to determine influences of flow regimes and discrete events on invertebrate community composition. I found high community variability within sites, illustrated by seasonal measures of beta diversity and nonmetric multidimensional scaling (NMDS) plots. I observed notable patterns of NMDS data points when invertebrate abundances were summarized by summer versus winter surveys. These results suggest that there is a difference within the communities between summer and winter seasons, irrespective of differences in site hydroclimate. Estimates of beta diversity were the best metric for summarizing and comparing diversity among sites, compared to richness difference and replacement. Seasonal measures of beta diversity either increased, decreased, or stayed constant across the study period, further demonstrating the high variation within and among study sites. Regime shifts, summarized by regime shift frequency (RSF) and mean net annual anomaly (NAA), and anomalous events, summarized by the power of blue noise (Maximum Blue Noise), were the best predictors of macroinvertebrate diversity, and thus should be more widely applied to ecological data. These results suggest that future studies of community composition in freshwater systems should focus on understanding the cause of variation in biodiversity gradients. This study highlights the importance of considering both flow regimes and discrete anomalous events when studying spatial and temporal variation in stream communities.
ContributorsSainz, Ruby (Author) / Sabo, John L (Thesis advisor) / Grimm, Nancy (Committee member) / Stampoulis, Dimitrios (Committee member) / Arizona State University (Publisher)
Created2021
Description
Functioning freshwater ecosystems are widely recognized as a planetary boundary for the continued human inhabitation of our planet, but little is known about the tradeoffs at the nexus of food, energy and water. In this dissertation I explored the effects of hydrologic variability in the Lower Mekong Basin (LMB) on rice production and functional structure of fish catches. I then examined the tradeoffs at the intersection of fish and rice harvest as a function of hydrologic variability and modeled production under novel engineered hydrologic scenarios. I modeled rice production using a Multivariate Autoregressive State Space (MARSS) model and mechanistically tested for the effect of saline intrusion. I found rice production to be heterogeneously affected by hydrology; in saline afflicted areas, floods had a positive effect size on production, whereas in non-saline afflicted areas, floods had a negative effect size on production. To address hydrologic filtering of the functional structure of fish catches, I collected thousands of specimens from over 100 LMB species in collaboration with Cambodia’s Inland Fisheries Research and Development institute and the Royal University of Agriculture. LMB fishes comprise a large portion of the 1,200 known species in the basin and have historically provided a substantial amount of animal protein to 60 million people in the region. Using an RLQ, co-inertia analysis, I found four functionally relevant morphological trats that were significantly associated with hydrologic variation—mouth position, maxillary length, relative body depth, and relative head depth. These traits are associated with many of the threated species in the LMB, which make up a large portion of the 1200 known species in the basin and have historically provided a substantial amount of animal protein to 60 million people in the region. To examine the tradeoffs within food systems, I used MARSS maximum likelihood estimation to forecast fish and rice production throughout the LMB under different hydrologic scenarios. I end my dissertation with an opinion piece on NexGen Mekong Scientists, a program I started in 2020 with funding from the United States Department of State.
ContributorsHolway, Joseph Henry (Author) / Sabo, John (Thesis advisor) / Grimm, Nancy (Committee member) / Holtgrieve, Gordon (Committee member) / Winemiller, Kirk (Committee member) / Hanemann, Michael (Committee member) / Arizona State University (Publisher)
Created2024