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Odonata as biological indicators of habitat quality in restored wetlands in the Arizona borderlands
No full textClimate change has led to severe impacts on aquatic habitats and biodiversity in the US-Mexico border region, with permanent streams, seasonal lakes, and playas drying intermittently or completely in recent decades. The purpose of this study was to assess Odonata as general indicators of ecosystem health, and to identify habitat-specialist taxa that could, if present, indicate the presence of habitat suitability or, if absent, a decline in habitat quality. Water sources in the Chiricahua Mountains region and nearby vicinities in the Southwest of Arizona were surveyed in 2020 for assemblage composition of adult Odonata. A total of 52 species (30 dragonfly and 22 damselfly species) were identified during the growing season. These species belonged to three families of Anisoptera, of which Libellulidae was dominant, and three families of Zygoptera. Adult abundances increased significantly during mid-summer months and decreased rapidly by September. Also, four families of Odonata nymphs were detected, with Libellulidae dominating the aquatic larval assemblage.Analysis of larval versus adult abundance data revealed high among-site variation in larval:adult ratios, with three general patterns over the field season. The first pattern is that some sites supported high species richness and large numbers of adult Odonata, but no nymphs whatsoever. The second pattern indicated that sites with intermediate area and habitat quality showed approximately equal larval:adult ratios. Lastly, late in the field season adults were largely absent, while larval abundances at most sites were unchanged, indicating high temporal variability in adult distribution, but relative constancy of larvae. Non-metric multidimensional scaling (NMDS) ordination indicated assemblage differences between lentic and lotic sites, and also revealed a third aquatic habitat, the “semi-lotic” type. In addition, the NMDS analysis fit the physical and water quality variables to see which are most closely associated with the overall ordination. Pearson correlation analysis identified positive but weak correlations among several physical and water quality variables. Such relationships may indicate changes in habitat quality. Dufrene-Legendre Indicator Species Analysis added additional resolution to the selection of potential indicator species. That analysis revealed the habitats for which particular individual species may serve as indicators. For example, Argia tonto and Hetaerina vulnerata were clear indicators of lotic habitats, while Enallagma civile and Anax junius were indicators of lentic habitats. Taken together, the results from ordination and indicator species analysis allowed me to identify a suite of relatively common species that were habitat specialists. Ten taxa were determined as candidates for an initial indicator assemblage. More study will lead to further refinement, and additional work on sampling protocols is needed to develop an efficient mixed-species monitoring approach for aquatic habitats.
My results indicate that the Odonata can serve as indicators of habitat quality and environmental change. By selecting specialist species indicative of the different aquatic habitats (lentic, semi-lotic, lotic), and applying the suggested abundance criteria, individuals conducting aquatic habitat monitoring can develop an initial assemblage of indicator species, and refine that assemblage iteratively by adding additional species that are tied closely to specific habitats or habitat characteristics.
My conclusions are preliminary, but are encouraging with respect to the use of Odonata as indicators of aquatic habitat quality. Using the Odonata as indicators can help refine and improve wetland restoration and management, leading to improved ecological, economic, and social wellbeing in increasingly water-challenged arid regions
Geochronological analysis as a test of the presence of the Sonora allochthon in the Sierra Las Pintas, Baja California, Mexico
Get PDFFormation of the final supercontinent, Pangea, culminated in late Paleozoic time with closing of the Rheic ocean and collision of Gondwana and Laurentia. This resulted in the hypothesized 3,000-km-long Ouachita-Marathon-Sonora orogenic belt (OMS) along the southern margin of Laurentia. The Sonora allochthon, the westernmost segment of the OMS, is dominantly located in Chihuahua and Sonora, Mexico, but recent studies have suggested that the orogen continues into northern Baja California, where sedimentary rocks in the Sierra Las Pintas have been correlated to allochthon stratigraphy in Sonora. This study provides the first detrital zircon geochronological analysis of the Sierra Las Pintas to test the hypothesis that Sonora allochthon strata are present and further correlation can be made to the Sonora allochthon documented in central Sonora. Detrital zircon geochronology of the Sierra Las Pintas strata indicates major sources from the Peninsular Ranges batholith and the Permo-Triassic arc, as well as minor sources from Gondwana, the Grenville orogen, Granite-Rhyolite provinces, Yavapai-Mazatzal provinces and the Archean craton. Provenance analysis suggests that most of the detritus was derived from the Peninsular Ranges batholith to the west, the Cordilleran Permo-Triassic arc to the northeast, crustal provinces of the Laurentian craton to the north, and Gondwana to the south. A Late Cretaceous maximum depositional age is determined for Sierra Las Pintas strata and stratigraphic analysis indicates deposition in the Peninsular Ranges batholith forearc along the continental slope and ocean basin. Geochronologic analyses suggest that the Sonora allochthon is not present in the Sierra Las Pintas and the succession cannot be correlated to the Sonora allochthon in central Sonora. Provenance interpretation of strata in the Sonora allochthon of central Sonora agrees with previous literature and provides strong detrital zircon evidence of Gondwanan source, which has rarely been identified in previous studies. Although the results of this study do not support the hypothesis that the Sonora allochthon is present in the Sierra Las Pintas, the strata record a mixed provenance of Gondwanan and Laurentian source regions, as well as Cretaceous Cordilleran arc activity
Development and Validation of a Web-based L2 Pragmatic Speaking Test in the University Context
No full textPragmatic competence has been increasingly recognized as a component of academic language proficiency assessment (Youn, 2018). However, the practicality of administering L2 pragmatic competence assessments involving interlocutors remains problematic (e.g., high labor cost) (Ikeda, 2017). The pandemic makes it even more difficult to administer role-play or paired speaking tasks in person. Therefore, there is a strong need for such pragmatic speaking tests to be administered online. Another issue of L2 pragmatic competence assessment is construct under-representation. The constructs of performance-based assessments and some English proficiency tests (e.g., IELTS speaking) also require additional investigation (Roever, 2011) because the tests are not completely measuring what testing agencies intend to measure.
The primary purpose of this study is to present the test development process and validity evidence for the Second Language Pragmatic Test (L2PT). This online test was developed to serve as a diagnostic test to evaluate pragmatic competence in spoken interaction for English as a Foreign Language (EFL) and English as a Second Language (ESL) learners. The target test takers were either studying or wanted to study at a North American University.
The web-based L2PT was developed using Python and JavaScript, and was hosted using Amazon Web Services (AWS). The test has three sections which includes 25 test items and takes approximately an hour to complete. The development of the L2PT was guided by the Discursive Approach to L2 Pragmatics (Kasper, 2006) framework, and informed by politeness theory (Levinson, 1987). The L2PT intends to measure constructs including task completion, language use, turn-taking, and interactional fluency. The language use situations of the L2PT were chosen based on previous needs analysis (Youn, 2018), corpus study (Conrad et al., 2006), and expert opinions. The rating criteria development was based on a data-driven approach (Youn & Chen, 2021). The L2PT and the rating criteria went through multiple rounds of piloting and revisions.
The test validation process utilizes the argument-based validity framework (Kane, 2013; Knoch & Chapelle, 2017; Chapelle et al., 2008). To provide validity evidence of the test, 112 EFL and ESL learners and eight raters were recruited. The rating was designed using an anchored rating design in which raters scored 30% of test takers’ performance and the remaining test takers were scored by at least two raters.
The validation process involves a Sequential Mixed Methods approach. For the quantitative analysis, the raters’ scores were analyzed using the Multi-Facet Rasch Measurement (MFRM) as implemented in the FACETS (Linacre, 2014) software. Four facets were included in the analysis: test takers, raters, rating criteria, and tasks. In terms of qualitative analysis, post-rating interviews were conducted from the raters to shed light on the rating experience, rating criteria, and test design. The raters’ insights and comments were summarized using content analysis.
The discussion of the quantitative and qualitative results is presented following Kane’s (2013) validity framework. For the domain inference, the results show that the development process of L2PT followed a good test development practice. For the evaluation inference, although the 4-point scale and the test items were relatively easy for the test takers, the rating criteria for the L2 pragmatic speaking test can function as intended in an EAP context in relation to the rating process, and the test administration process was appropriate. As for the generalization inference, there is some evidence to show that test takers are expected to receive scores that can measure their true ability.
The findings reveal the following: (1) The possibility of administering L2PT online, (2) Sufficient evidence to support the domain definition, evaluation inference, and generalization inference, (3) Design process for future pragmatic speaking tests. This dissertation exemplifies a positive step toward developing the pragmatic speaking test that can be administered online. The conclusion also provides methodological, research and pedagogical implications for using and implementing the L2PT
THE LIVED EXPERIENCES OF MENTAL HEALTH TECHNICIANS WORKING AT AN INPATIENT PSYCHIATRIC UNIT SERVING RURALLY LOCATED PATIENTS
No full textThis qualitative Hermeneutic phenomenological study explored the lived experiences of four mental health technicians (MHTs) working at an inpatient behavioral health unit (BH unit) serving predominantly rurally-based patients. Their unique perspectives were shared to address the paucity in the literature with this specific population. In BH units, MHTs have the most direct patient interaction time (Buchbinder, 2003; Jenkins & Elliott, 2003) therefore research directed at MHTs is thought to create overarching benefits extending to patient care through combatting impairment and burnout. This study takes place at an inpatient BH unit that is situated within a medical hospital in the Southwest region of the United States. A demographic questionnaire, face-to-face semi-structured and unstructured interview questions were used, as well as researcher journaling to reflect on the interview process. Analysis utilized Interpretive Phenomenological Analysis. Participants identified rewarding aspects of their work (strong treatment team, feeling connected to their patients, and feeling appreciated), and perceived pitfalls of their work (aspects of work that felt out of MHTs’ control). Further, participants identified external barriers impacting rural patient outcomes (lack of follow up care and resources, and culture specific factors). Participants also reported strong overall wellness, which is attributed to their ability to overcome challenging work experiences. Proactively addressing wellness needs and awareness of one’s emotional triggers are also viewed as necessary to prevent lowered wellness and subsequent impairment in MHTs’ work. Finally, participants shared suggestions to improve and maintain job satisfaction (receiving ongoing supervision, better follow up services for rural patients) and spoke to the value of long-term staff on the unit. Additional research with larger sample size across multiple organizations will provide much needed data on job satisfaction, wellness, and burnout in front line staff on inpatient behavioral health units
Multiple-Wavelength Phase Retrieval With Digital Holographic Microscopy
No full textThe phase of an image is very important because it is the phase, not the amplitude, that carries most of the information in an image. A traditional bright-field microscope only captures the amplitude information from a sample, and are therefore not of great use in applications where the sample is partially or totally transparent. Digital Holographic Microscopy (DHM) provides a phase retrieval technique that can obtain both the amplitude and phase of a sample. In this thesis, an iterative phase retrieval method for DHM using two illumination wavelengths is proposed which exhibits high immunity to noise and yields wrap-free phase images of biological samples when the image is reconstructed. Experimental results of human cheek cells, human blood smear, and neurons are presented to demonstrate the approach
Trait-Based Approaches to Dryland Restoration
Get PDFLand degradation leads to the loss of ecosystem functioning such as primary productivity, weed suppression, and erosion mitigation. Trait-based approaches to restoration can improve the outcome of restoration treatments, especially in challenging areas to restore such as drylands. Each of the chapters in my dissertation address trait based approached to dryland restoration: chapters 2 and 3 are focused on improving the survival of restoration seeding and planting treatments by matching plant traits to environmental conditions and chapter 4 addresses the issue of rebuilding ecosystem functioning through restoration. Chapter 2 involves an analysis of a long-term restoration outcomes database for the Colorado Plateau, I found that matching trait values to environmental conditions improved restoration outcome. In this case temperature seasonality along with seed mass and plant height best predicted seeding success. This chapter had some limitations since I was working with a large database and additional trait data were not available, therefore chapter 3 investigates similar questions with a more controlled approach that gave higher-resolution data to compare number of individuals that survived versus what was planted. Most restoration of large areas is done with seeding, however the experiment in chapter 3 and 4 jump-started the establishment of restoration species through a transplant experiment so I could investigate additional questions such as the impact of the restored community on ecosystem processes. Through the RestoreNet biodiversity-ecosystem functioning experiment I had two main questions: how does plant functional composition influence survival in restoration? And, once established, how does a restored community influence ecosystem functioning? First, I found that the species with greatest survival had multiple trait strategies including drought tolerance and drought escape. A combination of slow-growing drought tolerant leaves and fast-growing, drought escaping roots promoted survival across sites. Additionally, in chapter 4 I found that recovery of aboveground primary productivity supported the recovery of other ecosystem functions including weed suppression and erosion mitigation. There were certain trait strategies, such as drought tolerant, yet acquisitive leaves and roots that lead to greater aboveground productivity. These results can aid land managers in selecting the species to use in restoration that can establish given the conditions of a site, and that have a positive impact on rebuilding ecosystem functions of concern. These trait-based approaches are a powerful tool for drylands that are difficult to restore but cover nearly half the earth’s terrestrial surface
Do flower phenology and traits vary across species provenances and impact plant-pollinator interactions?
Get PDFThe response of plant-pollinator interactions to climate change is a growing body of research. Pollinators are key components of most terrestrial systems, and most plants depend on these mutualisms for reproduction. This common garden study aimed to understand how climate provenance is associated with the phenology of flowering and floral traits, and subsequently how the variation in phenology and floral traits is associated with the abundance and richness of pollinator functional groups. Eight populations of ten common forb species were collected across a climate gradient in the southwestern US and planted in a common garden. Populations were measured for phenology and floral traits (abundance, corolla dimensions) and observed for interactions with insect visitors. Regression analyses were conducted to determine whether population trait variation was predicted by provenance climate, with subsequent correlation analyses to determine if pollinator responses (richness, activity) were associated with trait variation. The majority of the ten forb species demonstrated some degree of trait variation that was predicted by climate; however, the direction and degree of response was variable among species. Compared to the high degree of climate-trait associations within the study plant species, there were few significant responses detected within the pollinator community. However, a small subset of phenological and floral traits impacted pollinator functional group richness/abundance; namely, date of peak floral output and peak floral abundance. These traits were variable between provenances and predicted by climate source, suggesting that climate influence on traits can have a direct implication for some plant-pollinator mutualisms
Mycorrhizas under Arctic shrub expansion: Effects of temperature, nutrient limitation, and host species on symbiotic root processes
Get PDFIn the nutrient limited Arctic tundra, mycorrhizae greatly influence nutrient cycling, providing up to 86% of nitrogen (N) to their host plants. As the Arctic warms, both nutrient availability and mycorrhizal host shrub abundance are increasing in tundra ecosystems. The resulting changes in mycorrhizal community and function are likely to affect not only nutrient, but also carbon (C) dynamics. In this dissertation, I studied how mycorrhizal-associated nutrient cycling may change with future warming, increased nutrient availability, and shifts in host plant abundance by pairing measurements of degradative extracellular enzymes on mycorrhizal roots with 1) mycorrhizal fungal identity, 2) aboveground plant abundance and height, and 3) another symbiotic root process occurring on the same shrub—N fixation. In chapter 2, I tested the effects of long-term experimental warming and fertilization on ectomycorrhizal fungal community and root enzyme activity. Warming tended to increase enzyme activity while fertilization decreased activity. Though these responses were partially explained by changes in EcM fungal community, our findings also suggest changes in enzyme activity were taxon-specific. In chapter 3, I further tested how nutrient limitation affected EcM as well as ericaceous shrub abundance and root enzyme activity, measuring non-linear responses across a long-term experimental soil fertility gradient. I found evidence of the co-expansion of ericaceous shrubs along with deciduous EcM shrubs and support for the potentially increased relative importance of EcM root enzymes compared to those of ericaceous roots in the degradation soil organic matter a future tundra. In chapter 4, I explored drivers of root enzyme activity and N fixation on Siberian alder, a deciduous EcM shrub found in boreal and Arctic Alaska. Across a latitudinal gradient, root enzyme activity and N fixation were correlated. Furthermore, the direction of this correlation appears to depend on relative availability of soil N and phosphorus. Overall, mycorrhizal root enzyme activity is highly responsive to changes in temperature, nutrient availability, and host species. However, these responses are nuanced and the resulting changes in tundra nutrient cycling will depend on mycorrhizal fungal identity, shrub species, the magnitude of heightened nutrient availability, interactions with other symbiotic partners to shrubs, and, most commonly, the type of enzymes present
Probing the structure and properties of the deep eutectic solvent choline and geranate at the vacuum/liquid interface using molecular dynamics
No full textIonic liquids (IL) have become a recent focus of material science research due in part to their structural properties, high thermal stability, and biocompatibility. In this research we focus on the deep eutectic solvent (DES), a specific subclass of ILs, composed of choline and geranate (CAGE). Previous research regarding applications of CAGE have investigated its ability to function as an antiseptic agent and its ability to transport large biomolecules such as insulin. As a result in this research we investigated the molecular interactions of CAGE at the interface as a means to provide information in the structural stability of CAGE solutions. A computational approach was implemented to study the interface interactions of CAGE and CAGE:water systems in the presence of a vacuum/liquid interface. Using molecular dynamics (MD) methods, molecular aggregation of each species of CAGE was measured with radial distribution data (RDF) to occur in the presence of a vacuum/liquid interface. The surface tension of solution of CAGE at varying mole ratios were found to linearly increase as the mole ratio of water increased, correlating with increased spatial orientation of molecules observed at the interface. Thermal expansion and isothermal compression coefficients were also obtained for all solutions, providing information regarding both the stability of CAGE solutions as well as the effect of water on stability. Diffusion coefficient data obtained for all systems also indicated the role water plays in increase the diffusion of CAGE in solution is linked to the increase hydrogen bond network imparted by water
Exploring the Work-Life Balance of High School Assistant Principals with School-Aged Children at Home
No full textThe high school assistant principal position is a complex and demanding role. Being a parent to school-aged children is also a complex and demanding role. For high school APs who have school-aged children at home, the ability to maintain a healthy work-life balance is essential to their ability to effectively fulfill both professional and personal responsibilities. This study was conducted to explore the work-life balance of high school APs with school-aged children at home and sought to identify ways in which their leadership team, family, and friends could support and promote their work-life balance as well as identify specific strategies used by high school APs to support and promote their own work-life balance.Participants included high school assistant principals from comprehensive campuses in Maricopa County, Arizona, that employ three or more full time assistant principals. Initially, all qualifying assistant principals were invited to complete a questionnaire to collect personal and professional demographic data. Based on that data, assistant principals with school-aged children at home were identified and the researcher invited high school assistant principals who were employed under a 12-month contract, resided with a partner in a committed and/or married relationship, and who had two or more school-aged children at home to participate in two focus groups, one male and one female. Each focus group was asked how fellow members of their leadership team, family, and friends support and promote their work-life balance, ways in which they could better support and promote their work-life balance, and strategies they use to support their own work-life balance. The focus group responses were transcribed, reviewed for accuracy, analyzed, and summarized.
The findings of this study suggested a significant need for additional support for females in the high school assistant principal position with school-aged children at home. On a larger scale, the findings suggested an overall gap in society’s acceptance and support of females in leadership roles. There is evidence to show a significant difference in the mental and emotional load carried by males and females, specifically the responsibilities related to family and household