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Deconstructing the "Apache" Identity: A History of the San Carlos Apachean Peoples
No full textHistorians of “Apache” history have continuously told the stories of the Chiricahua Apachean peoples and Goyathlay’s (Geronimo) resistance to the incursion of the U.S. Army. However, the attention afforded to these peoples and the lack of understanding regarding the cultural contingencies of Apachean history, leaves the story incomplete and unfulfilled. Consequently, academics fail to provide two very important and necessary components of the Apachean and Indigenous histories at the San Carlos Reservation. First, that the issue of identity remained a point of contention for the Indigenous peoples consolidated near the San Carlos Agency during the nineteenth century, and second, the history of the Western Apachean peoples, specifically, continues into the twentieth and twenty-first centuries. The Apachean peoples of the “San Carlos Apache Tribe,” as they are known in the modern-era, experienced a series of events that culminated in the creation of a “San Carlos Apache” identity. This adherence to a manufactured political identity dissuades members from incorporating traditional concepts of identity that, in conjunction with a Westernized tribal government, undermines traditional Apachean identifiers in favor of a colonial designation
Barriers and Challenges to the Adoption of Collaborative Project Delivery Methods: A Multiple-Case Study Analysis
Get PDFThe last 30 years have seen considerable advantages afforded to those who chose to adopt more collaborative project delivery methods (IPD, Progressive Design Build) in the Construction Industry; however, despite these benefits, construction projects utilizing collaborative delivery methods still only account for a small fraction of overall construction deliveries. This research focused on probing leading industry professionals to better identify the barriers and challenges which are currently preventing project stakeholders across the United States from adopting these more collaborative project delivery methods, particularly first-time adopters. This study collected data from semi-structured interviews with 13 professionals in the Construction Industry who had experience with collaborative project delivery methods. Detailed analysis of stakeholder responses using NVivo software led to key insights associated with the implementation of IPD and Progressive Design Build projects including those related to teaming, learning, and administration. A new class of challenges is proposed related to managerial obstacles. The implication of this research is that appropriately recognizing and categorizing the pitfalls associated with the implementation of collaborative project delivery methods can provide Construction Industry professionals with a valuable framework for formulating effective solutions to overcome them
Three-Dimensional Anti-Jamming Array Processing for GNSS-Based Navigational Aid Inspection
Get PDFGlobal Navigational Satellite System (GNSS) Radio Frequency (RF) links are susceptible to interference. In signal compromised environments, the capability to combat RF interference (such as jamming) is necessary. Techniques and results of applying adaptive anti-jamming beam/null-forming processing to the measured three-dimensional (3D) and two-dimensional (2D) radiation patterns of L1-Band RHCP GNSS antenna arrays are investigated. Also, for reference studies in this thesis and for verification of null-forming methods, an S-Band antenna array is investigated. I developed a small-scale 2 by 3 and 1 by 6 custom arrays along with a 7-element circular array for demonstrating the GPS L1-Band operation. For the S-Band, a pre-built 1 by 8 linear array was used.
The visualization of the GPS array pattern through synthesis and direct measurements serves as the basis for algorithm implementations. Individual antenna element measurements are collected first and then, in post-processing, nulling techniques are applied. A digital beamformer generates weighted vectors for each element based on the locations of the multiple interfering signals. The covariance matrix of the interfering signals is utilized. Its inverse is taken and multiplied by the steering vector of the desired signal.
The goal is to optimize the locations and depths of the nulls to suppress the unwanted interference while still having the main beam directed toward the desired signal. Generated beam-forming coefficients are applied through digital post-processing and through an analog phased array controller. The digital and analog methods are compared against each other. The evaluation of these null-forming techniques and measurement processes will be beneficial for the analysis of both civilian and military GNSS-based landing and navigational support systems
Machine learning assisted molecular simulations / mass spectrometry data analysis and rational design of antibacterial Co3O4 nanowires flagella
No full textIn chapter one, inspired by the recent work from Noé and coworkers on the development of machine learning based implicit solvent model for the simulation of solvated peptides [Chen et al., J. Chem. Phys. 155, 084101 (2021)], here we report another investigation of the possibility of using machine learning (ML) techniques to “derive” an implicit solvent model directly from explicit solvent molecular dynamics (MD) simulations. For alanine dipeptide, a machine learning potential (MLP) based on the DeepPot-SE representation of the molecule was trained to capture its interactions with its average solvent environment configuration (ASEC). The predicted forces on the solute deviated only by an RMSD of 0.4 kcal/mol/Å from the reference values, and the MLP-based free energy surface differed from that obtained from explicit solvent MD simulations by an RMSD of less than 0.9 kcal/mol. Our MLP training protocol could also accurately reproduce combined quantum mechanical molecular mechanical (QM/MM) forces on the quantum mechanical (QM) solute in ASEC environment, thus enabling the development of accurate ML-based implicit solvent models for ab initio-QM MD simulations. Such ML-based implicit solvent models for QM calculations are cost-effective in both the training stage, where the use of ASEC reduces the number of data points to be labelled, and the inference stage, where the MLP can be evaluated at a relatively small additional cost on top of the QM calculation of the solute. (Chapter 1)
In chapter two, we will specifically focus on the pKa values of ionizable residues of pro- teins. As these residues play important roles in protein stability dynamics, aggregation, binding and function [1], it is essential to have an accurate determination of pKa values of
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these residues in order to accurately establish protein models in experimental or compu- tational studies. However, pKa value prediction is rather challenging due to many factors such as variable local environment, coupling and interactions among ionizable groups. (Chapter 2)
In chapter three, single-cell mass spectrometry (SCMS) is an emerging tool for studying cell heterogeneity according to the variation of molecular species in single cells. Although it has become increasingly common to employ machine learning models in SCMS data analysis, such as the classification of cell phenotypes, the existing machine learning models often suffer from low adaptability and transferability. To overcome these limitations, here we proposed a meta-learning-based model, MetaPhenotype, for classifying pairs of cell lines (primary and metastatic melanoma). Our results show that, compared to standard transfer learning models, MetaPhenotype can more rapidly achieve a high accuracy of over 90% with fewer new training samples. Overall, our work opens the possibility of accurate cell phenotype classification based on fewer SCMS samples, lowering the demand of training sample acquisition. (Chapter 3)
In chapter four, considerable progress has been made on the synthetic chemistry and an- tibacterial application of tricobalt tetroxide (Co3O4) nanomaterials. However, the current approaches to designing and synthesizing Co3O4 nanomaterials are complicated and hard to manipulate. Herein, we developed a one-pot strategy to synthesize Co3O4 nanowires at room temperature with an antibacterial activity. The synthesis process relied on the use of engineered bacterial flagella as a biotemplate, which were genetically modifiable protein nanofibers naturally attached to bacteria for assisting their swimming. We found that the flagella displaying negatively charged peptides (E10 and E20) effectively induced the nucleation of Co3O4 nanoparticles from a cobalt chloride (CoCl2) precursor solution on their surface to form polycrystalline nanowires, with the E20-flagella being more effective than the E10-flagella. However, the wildtype flagella or those displaying neutral (G10) or positively charged (K5) peptides did not effectively induce the Co3O4 nucleation on the flagella. A mechanism investigation discovered that an amorphous phase of Co3O4 was
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first formed rapidly on the E20-flagella, followed by a crystallization process with both the good crystallinity and nanowire water-dispersibility reached in 2 h. We also found that the E20-flagella formed the Co3O4 nanowires with the good crystallinity at a precursor solu- tion of 1 mM. The E20-flagella-templated Co3O4 nanowires, synthesized using the optimal mineralization conditions (2 h and 1 mM CoCl2) showed the most effective killing of gram- negative bacteria such as Escherichia coli. This work suggests that flagella with tunable peptide sequences are biotemplates for forming antibacterial nanowires at environmentally benign conditions. (Chapter 4
Evaluating the Impacts of Wastewater on Aquatic Biota in the Red River Basin
Get PDFThe capture and reuse of wastewater is a promising strategy for increasing water
availability, but the environmental benefits and costs are poorly quantified. In water-limited river
basins, wastewater outfalls are an important component of stream flows and may buffer
ecosystems from drought. How does wastewater influence the biodiversity of fish and
macroinvertebrate communities? We investigated two competing hypotheses. First, we
hypothesized that if wastewater flows buffer aquatic communities from drought, then measures
of biodiversity should be higher at sampling sites near wastewater outfalls than at sites not near
wastewater outfalls. On the other hand, if wastewater outfalls negatively impact water quality or
homogenize flow regime, then measures of biodiversity may be lower at sites near wastewater
outfalls. To test these competing hypotheses, we calculated a suite of biodiversity indices at 320
biological sampling sites in the Red River basin and analyzed for significant differences in
communities based on proximity to wastewater outfalls. We found that wastewater outfalls had
varied impacts on biodiversity in fish and macroinvertebrate communities, and in most cases the
effects were not significant. Findings from this study could be used to provide insight to
management decisions on wastewater reuse initiatives in beneficial subbasins while minimizing
harmful ecological impacts
Space Application of Novel Solar Cells
Get PDFMultiple solar cell technologies from three different generations of photovoltaic cells were studied for space applications. The GaAsSb, crystalline first-generation solar cells were studied under low-intensity-low-temperature (LILT) space conditions. In order to examine performance of the cells in energetic irradiation environments this system was exposed to electron irradiation of 1 MeV. Improvement in the carrier extraction was observed in short wavelength regime in the external quantum efficiency (EQE) measurements after electron irradiation. Transmission electron microscope (TEM) images indicated enhanced crystallinity near the top of the cells, coinciding with the region that short wavelength incident light is absorbed. The Cu(InGa)Se2 (CIGS), thin film second generation solar cells were studied under space LILT conditions. These conditions included low Sun intensity at the outer planets in the solar system and their respective temperatures. The unencapsulated CIGS cells were irradiated with 1.5 MeV protons of varying fluence, resulting in significant damage to the performance of the cells. The damage rooted in irradiation induced defects which diffused toward the grain boundaries and resulted in reduced shunt resistance. The degradation manifested more pronounced at low temperatures of the outer planets. A Fresnel lens concentrating system was suggested for the CIGS solar cells to compensate for low light intensity of the outer planets. This concentrating system has a remarkable effect on improving the efficiency of the cells at the planets with dim conditions. Multiple structures of the perovskite solar cells, third generation photovoltaics, were studied in extreme space conditions of irradiation and temperature. Proton irradiation induced defect states inside the perovskite solar cells compromised the performance of the cells. Although, after two months of keeping samples in the dark we observed self-healing in the perovskite cells, resulting in performance of the cells to become very similar to the pre-irradiation conditions. We observed that for irradiation with 1 MeV and extreme fluence level of 4 × 1014 (1/cm2) the solar cell stopped functioning after a few months. Through modifications in architecture of the FACsPb(IBrCl)3 solar cells, very high temperature, 490 K (217 °C), performance of the perovskite solar cells was achieved with 70% of the room temperature efficiency. The modifications to the FACsPb(IBrCl)3 perovsite solar cell included: First, use of a double cation (FACs) composition which improves the stability of the perovskite absorber layer. Second, a transparent conductive back contact was used to prevent metal migration or iodine-metal corrosion. Finally, a alumina-based nanolaminate was applied on top of the cell to prevent thermal decomposition due to loss of volatile species. The investigation of these solar cell technologies under extreme space conditions resulted in finding the weak points and also hidden capacities of these systems. In the case of CIGS solar cells grain boundaries facilitate shunting after irradiation. In perovskite solar cells aside from the stability problem, samples showed very high radiation tolerance and extremely good performance at temperatures more than 200 °C
Information Transparency and the Effectiveness of R&D Tax Credits
No full textUsing staggered changes in state-level R&D Tax Credits (RTC), I investigate the effectiveness of RTCs offered by U.S. states and their dependence on information transparency. The results show that RTCs increase aggregated patenting activities within a state, with more substantial effects observed in states with transparent information environments, as measured by state adoption of the Inevitable Disclosure Doctrine (IDD) and aggregated peer information driven by presence of public firms in the same industry. Additionally, the evidence suggests that the impact of information transparency on individual firms’ reaction to RTCs varies depending on the tradeoff between benefits (e.g., reduced cost of capital, increased innovation efficiency, and more patent transactions) and costs (e.g., spillover effects of innovation). These findings have important implications for policymakers aiming to stimulate innovation with a given budget
Fire Side Chats to TikTok Influencer Tags: The Evolution of White House Computer-Mediated Communication to Youngsters
Get PDFThis study aimed to analyze how young people understood emerging changes in White House communication, specifically that which utilized the collaboration of social media influencers. Convenience sampling was used to recruit participants at an American college. A total of 111 students participated in the study that showed two different videos of social media influencers at the White House, followed by questions that measured credibility, accommodation, and effects of messaging. The videos featured different levels of formality, as well as different aesthetics. Results revealed that these collaborative videos did not produce high levels of credibility, accommodation or gateway effects, but the less informal video prompted greater credibility, accommodation, and gateway effects than the more informal video. Collectively, these results indicate that White House and social media influencer collaborations in their current form as not incredibility persuasive and future research is needed to better understand if and how these collaborations can be altered to be more effective at reaching and influencing young adults
Using TikTok as a Reflective Teaching Tool
Get PDFThe purpose of this paper is to better understand the current reflective teaching practices of in-service teachers and to determine whether TikTok may be an effective and sustainable reflective teaching tool. There has been much discussion surrounding reflective teaching and how to develop and encourage reflection in preservice teachers (Calderhead, 1989; Liston & Zeichner, 1987; Loughran, 2002; Yost et al, 2000). Whether in-service teachers are consistently reflecting on their practice or the ways in which they are reflecting is not fully understood.
Three assumptions guided this study. First, consistent and intentional reflection is an invaluable tool for teachers to grow professionally. Second, it is difficult to find the time to reflect meaningfully when teachers are wrestling with the everyday tasks and requirements of the job. Third, reflection is not a practice that can be meaningfully mandated. It has to be an organic teacher-owned process to be effective and sustainable.
There was a thorough investigation of the #teachertok community, and five teachers are showcased to demonstrate how this platform can be used to develop professionally. Also, an anonymous survey was distributed to in-service teachers to better understand how they are currently reflecting. Three teachers (one novice, two experienced) were asked to use TikTok to reflect on their teaching practices for a five-week intervention period. They participated in a small focus group both before and after the intervention and completed weekly check-in surveys, which summarized their reflections and gauged whether it was an onerous experience.
Results of the survey show that teachers are reflecting but not consistently. The findings of the intervention were positive, suggesting that TikTok is a useful reflective tool
The relationships between food security status, food insecurity coping strategies, and depression among single female caregivers
No full textAbstract
Background: Food insecurity is an ongoing problem in the United States. Certain groups, such as single females heading a household tend to be disproportionately impacted. This study examines food security status among single female caregivers of children and investigates the relationships between food security status, depression, and various food insecurity coping strategies.
Methods: Cross-sectional survey data was collected among a convenience sample of single female caregivers (n=94). The survey included measurements assessing food security status, various food insecurity coping strategies, depression, and sociodemographic variables. We examined the relationships between key variables using a series of linear and logistic regressions.
Results: Depressive symptoms were high among our sample, with over 70% of participants surpassing the scale’s cutoff for likely depression. There was a significant relationship between higher levels of food insecurity and increased depressive symptomology after controlling for sociodemographic controls (p = .004). We also found that higher levels of food insecurity were associated with use of more community, interpersonal, and intrapersonal coping strategies (p- values < .05). Greater use of community coping, interpersonal coping, and shopping and tradeoffs (intrapersonal) coping strategies were associated with increased depressive symptoms (p-values < .05).
Conclusion: The high rates of food insecurity and depression among our sample reiterates the need for further study and intentional interventions among single female caregivers. Examining food insecurity coping strategies may provide deeper insight into understanding food insecurity as well as help to clarify the relationship between food insecurity and depression