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- Creators: School of Life Sciences
- Resource Type: Text
- Status: Published
Description
Prochlorococcus marinus (MED4), a genus of marine picocyanobacteria that proliferates in open oligotrophic ocean, is one of the most abundant photosynthetic microbes in the world, estimated to contribute up to 10% of the ocean’s primary production. The productivity of these microorganisms is controlled by macronutrient availability in the surface waters. The ratio of macronutrients in the ocean was defined, by Alfred Redfield, as an elemental ratio of 106C:16N:1P. However, the C:N:P ratio varies based on region, season, temperature and irradiance, as well as the composition of the primary producers. In oligotrophic gyres, these nutrient ratios are elevated from the Redfield stoichiometry, but whether this ratio exerts influence on the growth rate of the organism has not been investigated. Elemental stoichiometry of available nutrients can affect the aggregation of organic carbon and exportation of the particles to the ocean depths. The purpose of this study was to investigate the effects of nutrient limitation on aggregation and transparent exopolymeric particle (TEP) production which aids in aggregation. My findings suggested that nutrient limitation reduces TEP production and does not increase aggregate volume concentration. With continued warming, certain regions of the ocean will become more oligotrophic, which further decreases the nutrient supply available for Prochlorococcus. My research shows that this could lead to decreased exportation of organic carbon matter to the depths of the sea.
ContributorsRoy, Kevin Thomas (Author) / Neuer, Susanne (Thesis director) / Cadillo-Quiroz, Hinsby (Committee member) / Cruz, Bianca (Committee member) / Department of Psychology (Contributor) / School of Molecular Sciences (Contributor) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
Description
Nutrient availability and ratios can play an important role in shaping microbial communities of freshwater ecosystems. The Cuatro Ciénegas Basin (CCB) in Mexico is a desert oasis where, perhaps paradoxically, high microbial diversity coincides with extreme oligotrophy. To better understand the effects of nutrients on microbial communities in CCB, a mesocosm experiment was implemented in a stoichiometrically imbalanced pond, Lagunita, which has an average TN:TP ratio of 122 (atomic). The experiment had four treatments, each with five spatial replicates – unamended controls and three fertilization treatments with different nitrogen:phosphorus (N:P) regimes (P only, N:P = 16 and N:P = 75 by atoms). In the water column, quantitative PCR of the 16S rRNA gene indicated that P enrichment alone favored proliferation of bacterial taxa with high rRNA gene copy number, consistent with a previously hypothesized but untested connection between rRNA gene copy number and P requirement. Bacterial and microbial eukaryotic community structure was investigated by pyrosequencing of 16S and 18S rRNA genes from the planktonic and surficial sediment samples. Nutrient enrichment shifted the composition of the planktonic community in a treatment-specific manner and promoted the growth of previously rare bacterial taxa at the expense of the more abundant, potentially endemic, taxa. The eukaryotic community was highly enriched with phototrophic populations in the fertilized treatment. The sediment microbial community exhibited high beta diversity among replicates within treatments, which obscured any changes due to fertilization. Overall, these results showed that nutrient stoichiometry can be an important factor in shaping microbial community structure.
ContributorsLee, Zarraz (Author) / Poret-Peterson, Amisha (Author) / Siefert, Janet L. (Author) / Kaul, Drishti (Author) / Moustafa, Ahmed (Author) / Allen, Andrew E. (Author) / Dupont, Chris L. (Author) / Eguiarte, Luis E. (Author) / Souza, Valeria (Author) / Elser, James (Author) / College of Liberal Arts and Sciences (Contributor) / School of Life Sciences (Contributor) / School of Earth and Space Exploration (Contributor)
Created2017-05-30
Description
I present the case for a fire-centric scholarship, and suggest the transition between burning living landscapes and lithic ones (in the form of fossil fuels) would make a good demonstration of what such scholarship might do and what its value could be.
ContributorsPyne, Stephen (Author) / College of Liberal Arts and Sciences (Contributor) / School of Life Sciences (Contributor)
Created2017-10-23
Description
Painting two grand stories, I set out to compare human-animal relationships, as realized by the Holy Cow among Hindus in India and stock and pet animals among people in America. The goal of these comparisons is to determine in what ways the relationships that Indians and Americans have towards animals can be made relevant to one another. This is done by concentrating on how the human perceptions of animals are informed by religious, political, and economic contexts, as well as how these perceptions inform the social costs of human-animal relationships within a society, as it pertains to both animals and humans. What I find is that the human-animal relationships are different in India and in America, but reveal similar tensions in both countries. In India, the Hindu Holy Cow is deified above the status of human, yet its embodiment of the Hindu cosmos and Hindu nationalist identity does not come without a cost for India as a society and nation. The American human-animal relationship is also caught in tension between two big perspectives. One, which is best exemplified by the stock cow, takes animals to be things of consumption, the other, which is best exemplified by the pet, makes animals into objects of anthropomorphism. Ultimately, the distinguished perspectives in India and America reveal divergent mechanisms, but comparable costs for humans and animals in both societies.
ContributorsCauthron, Samuel Lee (Author) / Henn, Alexander (Thesis director) / Broglio, Ronald (Committee member) / Historical, Philosophical & Religious Studies (Contributor) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
Description
Objective: To compare intra-operative and post-operative outcomes of total abdominal hysterectomy, total vaginal hysterectomy, total laparoscopic hysterectomy, and total robotic hysterectomy for benign conditions, as well as to conduct a cost approximation of each. Methods: Retrospective chart review of all hysterectomies by two surgeons between January 2017 and January 2019. For each patient, the following metrics were recorded and analyzed: age, BMI, medical history, abdominal/pelvic surgical history, surgical indication, route of hysterectomy, intra-operative complications, total operative time, time to discharge, estimated blood loss, post-operative complications, pain status, return to activities of daily living, and return to employment. Results: A total of 521 patients who underwent total abdominal hysterectomy (n=40), total vaginal hysterectomy (n=55), total laparoscopic hysterectomy (n=131), and total robotic hysterectomy (n=292) were analyzed. There were no significant differences among the groups in age, BMI, or surgical history. The total vaginal hysterectomy category included the highest percentage of pre-existing medical history (p=0.043, p=0.011). Of the four categories, total robotic and total laparoscopic hysterectomies involved shorter operative times (p=0.026, p=0.044), shorter inpatient stays (p= <0.001), fewer intra-operative complications (p= <0.001), decreased pain status (p= <0.001), and quicker return to both employment (p=0.039, 0.044) and activities of daily living (p=0.002). Total robotic hysterectomy showed less estimated blood loss (p= <0.001) and fewer post-operative complications (p=0.022, p=0.046) when compared to laparoscopic hysterectomy. Robotic hysterectomy was noted to have the highest OR-specific costs and total encounter costs. Conclusions: The two minimally invasive routes to hysterectomy, robotic and laparoscopic, appear to both be comparable in terms of intra-operative and post-operative outcomes, and are associated with improved outcomes when compared to abdominal and vaginal routes to hysterectomy. However, due to the high cost of robotic surgery, it may not be the most cost-effective approach.
ContributorsTehranchi, Darya (Author) / Kennedy, Denise (Thesis director) / Mayer, Gregory (Committee member) / Department of Psychology (Contributor) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
Description
Given the high prevalence of out-of-hospital cardiac arrest (OHCA), the low survival rate, the high morbidity rate, and the significant cost to both the patient and the system, it is imperative that we address any and all factors that contribute to recognition of a OHCA case, any barriers that prevent chest compressions, and improve medical care to treat OHCA events in order to increase survival rate, decrease morbidity, and lessen the economical burden of cardiac arrest events. Additionally, understanding the relationship between seizures and OHCA can help medical professionals, including Neurologists and other doctors, to explain to the public when one should call into EMS regarding a seizure-like event in the event of a possible OHCA. This would help to address and alleviate the result of this major public health concern.
ContributorsShee, Kameron James (Author) / Reddy, Swapna (Thesis director) / Sirven, Joseph (Committee member) / College of Health Solutions (Contributor) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
Description
This paper discusses the impact of substance use disorder (SUD) stigma on individuals with substance use disorders and details the development of a SUD Stigma Reduction pilot module for the Student Health Outreach for Wellness (SHOW) affiliated course (HCR 494 Complex Health - Immersion) offered at Arizona State University. This course was designed to educate pre-health professional and health professional students on complex health topics in an interprofessional, experiential-learning environment. The SUD and Stigma module developed in this thesis project provided students with information on SUDs and the opportunity to confront stigma, improving their perceptions on individuals with SUD.
The pilot module on SUD Stigma Reduction was researched, designed, and implemented in the HCR 494 course. After students completed the module, a retrospective pre-post survey was administered to evaluate the effectiveness of the module in two areas: content knowledge and personal perceptions. Only one student responded to the survey, placing limitations on analysis. The student’s response showed a general increase in understanding of the module material, matching the stated objectives, and positive changes in perceptions on people with SUDs. Due to the positive evaluation of the course, the pilot module was deemed successful and has been integrated into the HCR 494 course. Further research is necessary to determine the long term impact of stigma reduction modules in experiential learning courses.
The pilot module on SUD Stigma Reduction was researched, designed, and implemented in the HCR 494 course. After students completed the module, a retrospective pre-post survey was administered to evaluate the effectiveness of the module in two areas: content knowledge and personal perceptions. Only one student responded to the survey, placing limitations on analysis. The student’s response showed a general increase in understanding of the module material, matching the stated objectives, and positive changes in perceptions on people with SUDs. Due to the positive evaluation of the course, the pilot module was deemed successful and has been integrated into the HCR 494 course. Further research is necessary to determine the long term impact of stigma reduction modules in experiential learning courses.
ContributorsYee, Anna (Author) / Harrell, Susan (Thesis director) / Saewert, Karen (Committee member) / School of Life Sciences (Contributor) / Department of Psychology (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
Description
Morphological variation among individuals has the potential to influence multiple life history characteristics such as dispersal, migration, reproductive success, and survival (Wilder et al., 2016). Research has shown that individuals that are in better "condition" can disperse or migrate further or more successfully, have greater reproductive success, and survive for longer (Wilder et al., 2016; Heidinger et al., 2010; Liao et al., 2011), particularly in years where environmental conditions are harsh (Milenkaya et al., 2014). An individual's body condition can be defined in various ways, but is most often considered an individual's energetic or immune state (Milenkaya et al., 2014). Since these traits are hard to measure directly, researchers have instead used a variety of morphological proxy variables to quantify condition such as fat score (Kaiser, 1993), weight, ratio of weight to tarsus length (Labocha et al., 2014), a scaled mass index (Peig and Green, 2009), as well as hematological indices for immune system function (Fleskes et al., 2017, Kraft et al., 2019). However, there is mixed support regarding whether these condition indices relate to life history characteristics (Wilder et al., 2016; Labocha et al., 2014), and whether the relationship is linear (Mcnamara et al., 2005; Milenkaya et al., 2014). Additionally, although some researchers use multiple morphological proxy variables for condition (e.g. Warnock and Bishop, 1998), rarely have there been direct comparisons among proxies to validate that they measure the same trait. In this investigation, we define condition as an energetic state and we attempt to measure it by comparing two indices (fat score and the scaled mass index) to validate whether they measure the same trait in our study system, the great-tailed grackle (Quiscalus mexicanus). We found that the morphological proxy variables did not correlate with each other, indicating that they were not measuring the same trait. Further, the proxy variables did not correlate with reproductive success, measured as whether a female had a fledgling and whether a male held a territory containing nests. These results improve our understanding of measures of condition in grackles, and birds in general, and the importance of condition for reproductive success - a necessary component for selection to act.
ContributorsBerens, Jennifer (Author) / Langergraber, Kevin (Thesis director) / McCune, Kelsey (Committee member) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
Description
The rate of vaccinations has been consistently decreasing in the past years in children of ages 0-18. Multiple factors and barriers contribute to these low rates. This comparative case study investigated the accessibility of information regarding childhood vaccinations to parents in areas with differing poverty levels in the greater Phoenix region, specifically in the West Valley, Downtown Phoenix, and the East Valley. Pediatric clinics, public elementary schools, and public libraries were visited in each area to assess how much information was available where. The analysis produced unexpected results: the West Valley, which had the highest poverty level, contained the most amount of accessible information for parents in many languages, while the East Valley, with a low poverty level, had almost no information accessible to parents of these children. Implications for future research, policy, and practice are discussed. Based on these unexpected results, one recommendation is to develop a pamphlet that could be distributed to these public places to raise awareness of the importance of vaccinations in children to parents.
ContributorsShah, Veedhi (Author) / Bates, Denise (Thesis director) / Castillo, Elizabeth (Committee member) / College of Health Solutions (Contributor) / School of Life Sciences (Contributor) / School of International Letters and Cultures (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
Description
The rise in community-associated methicillin-resistant Staphylococcus aureus (MRSA) infections and the ability of the organism to develop resistance to antibiotics necessitate new treatment methods for MRSA. Geopolymers (GPs) are cheap, porous materials that have demonstrated adsorptive capabilities. In this study, GPs were investigated for their ability to adsorb whole MRSA cells and MRSA secreted proteins [culture filtrate proteins (CFPs)] as a complementary method of controlling MRSA infections. GPs have been synthesized with variable pore sizes (meso/macro scale) and further modified with stearic acid (SA) to increase surface hydrophobicity. Four GPs (SA-macroGP, macroGP, SA-mesoGP, and mesoGP) were incubated with whole cells and with CFPs to quantify GP adsorption capabilities. Following MRSA culture incubation with GPs, unbound MRSA cells were filtered and plated to determine cell counts. Following CFP incubation with GPs, unbound CFPs were separated via SDS-PAGE, stained with SYPRO Ruby, and analyzed using densitometry. Results indicate that macroGP was the most effective at adsorbing whole MRSA cells. Visual banding patterns and densitometry quantitation indicate that SA-mesoGP was the most effective at adsorbing CFP. Ultimately, GP-based products may be further developed as nonselective or selective adsorbents and integrated into fibrous materials for topical applications.
ContributorsGanser, Collin (Co-author, Co-author) / Haydel, Shelley E. (Thesis director) / Seo, Don (Committee member) / Borges, Chad (Committee member) / School of Earth and Space Exploration (Contributor) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05