Dispersion of the Birefringence of Crystal Quartz, Magnesium Fluoride, and Synthetic Sapphire

Accurate methods for characterizing birefringence are crucial for the design andproduction of optics that manipulate polarized light, especially for waveplates that require precise thickness to achieve a specific retardance at a given wavelength. Typically, the tolerances for polishing waveplates are approximately ± 0.25 μm. This thesis characterizes the birefringence of three commonly used waveplate materials: crystal quartz, magnesium fluoride, and synthetic sapphire and compares values of two independent experimental methods. Dispersion formulae for each material are established and verified against existing literature. The results indicate a high level of agreement between the two experimental methods, showing consistency within 1.0 × 10−5 for birefringence values across the wavelength range of 300-1800 nm. Furthermore, the experimental data align closely with the published values, with deviations within 1.0 × 10−5 for quartz and magnesium fluoride and within 3.0 × 10−5 for sapphire

The Gale Transform and the Pentagram Map

We prove that polygons under the higher dimensional pentagram map are projectively equivalent through the use of the Gale transform. Specifically, we demonstrate this for (k+3)-gons and (2k+2)-gons in a k-dimensional projective space. We begin by showing equivalence between historical definitions of the Gale transform, and then we propose a novel geometric definition of the Gale transform by extending Castelnuovo's approach for (2k+2) points. This new definition provides a nice geometric way to take the Gale transform of (k+s+2) points, as opposed to the standard linear algebra approach that is commonly used. Utilizing this new definition, we establish that the Gale transform and projective duality map commute. This is crucial in proving the projective equivalence of polygons under the higher-dimensional pentagram map

June 2024: Southwest Climate Outlook

This item from the Southwest Climate Outlook collection is made available by Climate Assessment for the Southwest (CLIMAS) at the University of Arizona with support from the University of Arizona Libraries. If you have questions, please visit https://climas.arizona.edu/

Hard Rock Mine Restoration in the Arid Southwest

The hard rock mining industry has left a legacy of degraded landscapes and waste disposal sites in need of reclamation. Revegetation of mining affected lands is a common method for mine reclamation that has demonstrated success across a variety of landscapes. This approach involves the establishment of diverse plant communities on mine wastes. Mine wastes are generally considered poor habitats for plant growth largely due to denuded and potentially toxic soil conditions. Further difficulties with plant establishment are found in arid lands due to scant, infrequent rainfall, and extreme temperatures. My dissertation explores different methods to enhance the success of revegetation efforts on copper mines in Southern Arizona. In Chapter 1, I explore how incorporating ecological theory in revegetation planning, namely facilitation, can help improve revegetation success. I assessed the plant communities and soil chemical properties underneath the canopies of a targeted nurse plant, desert broom (Baccharis sarothroides), and compared them to exposed conditions. Chapter 2 explored how different seed application techniques, mycorrhizal inoculation, and seeding season affect revegetation success. Chapter 3 analyzed the causes of revegetation failure on a tailings pile. The native shrub, brittlebush (Encelia farinosa), initially dominated the site after seeding in 2011. Over time, there was a gradual decline in the health of the brittlebush on site, and by 2023 nearly all individuals died with no other shrub species colonizing the site. We analyzed the belowground soil conditions to understand the causes of shrub die-off. Taken in conjunction, these chapters provide a thorough exploration of methods to improve revegetation success on hard rock mines

Preclinical Evaluation of the Mechanism Underlying Ketamine Activity as a Treatment for Parkinson's Disease and L-DOPA-Induced Dyskinesia

Parkinson’s disease (PD) is the second most common neurodegenerative disease worldwide. PD is characterized by the loss of dopaminergic neurons in the substantia nigra pars compacta leading to a commensurate reduction of dopamine in striatal terminals, a vital component of voluntary motor movement. The loss of dopamine output into the striatum elicits debilitating cardinal motor symptoms of bradykinesia, rigidity, resting tremor and postural instability. The current leading pharmacological treatment, Levodopa (L-DOPA), functions as purely dopamine replacement but also produces crippling negative side effects known as levodopa-induced dyskinesia (LID) after extended use for greater than 5 years of taking the drug. These adverse symptoms are defined by chorea and dystonia, abnormal involuntary movements and contraction of the limbs and facial muscles, that can be just as crippling as the original Parkinson’s disease symptoms. Therefore, there remains a critical unmet need for additional and more robust, non-dopaminergic pharmacotherapy treatment options for PD that can extend the therapeutic benefits of L-DOPA and support a greater quality of life for those with the disease. Previous research from our lab has shown that ketamine, a N-methyl-D-aspartate (NMDA)-receptor antagonist, produces both robust short-term anti-parkinsonian, and long-term anti-LID effects in a preclinical, 6-hydroxydopamine (6-OHDA)-lesioned rodent model of PD. Additional research from our lab exploring the mechanistic actions of ketamine has shown that the density of mushroom spines in the striatum positively correlates with LID severity. Through NMDA antagonism, ketamine causes a burst of glutamate that leads to cortical release of brain-derived neurotrophic factor (BDNF), which then binds to its receptor, tropomyosin receptor kinase B (TrkB), on the medium spiny neurons of the striatum and provokes a replacement of maladaptive, multi-synaptic dendritic mushroom spines with monosynaptic thin spines. Ketamine is a multi-functional drug that exerts its effects through NMDA receptor antagonism, binding of the TrkB receptor, and binding of the opioid receptors. This dissertation investigated if the use of a pan-opioid receptor antagonist, naloxone, blocks the anti-parkinsonian and/or anti-dyskinetic effects of ketamine treatment. The data indicate that naloxone dose-dependently added to the anti-parkinsonian activity of ketamine and extended the time-course of LID presentation, suggesting that the opioid receptor system differentially modulates the anti-parkinsonian and anti-dyskinetic effects of ketamine. There was additional investigation if two types of statin drugs differing in polarity, that have been shown to interfere with the direct binding of ketamine to the TrkB receptor, had differential effects on the ability to attenuate the development of LID both independently and combined with ketamine. We showed that the non-polar statin, Lovastatin, does not interfere with the anti-dyskinetic effects of ketamine, but combined with ketamine, they significantly attenuate LID. The polar statin, Pravastatin, by itself sensitized PD rats upon first exposure to L-DOPA, but the long-term anti-dyskinetic effect of ketamine is blocked by co-treatment with Pravastatin. Finally, we investigated if sub-anesthetic ketamine, that has been shown to be neuroprotective in other models of disease, also exhibits neuroprotective effects in a progressive model of PD. Our data indicates that ketamine treatment leads to significant behavior improvements in lesion severity and akinetic phenotype, suggesting a neuroprotective effect. Blockage of the TrkB receptor with compound ANA-12 showed that the neuroprotective effect of ketamine may be mediated through glial cells and reduction of inflammation rather than dopaminergic neuron survival. The preclinical studies presented in this dissertation provides new mechanistic insight into the anti-parkinsonian and anti-dyskinetic effects of ketamine and evidence to further support our groups ongoing clinical trial investigating sub-anesthetic ketamine treatment for individuals with Parkinson’s disease and L-DOPA-induced dyskinesia.Release after 08/16/202

Millimeter Wave Studies of Biogenic Elements in the Interstellar Medium

The unique conditions within the circumstellar envelopes (CSEs) of asymptotic giant branch (AGB) stars facilitate the formation of radical species and other complex molecules. While some of these molecules are destroyed within the envelope, their remnants contribute to the broader molecular lifecycle. Molecules containing the NCHOPS elements, those essential for life, are of particular interest in astrochemistry. This work presents millimeter-wave observations of CSEs and molecular clouds conducted using the Arizona Radio Observatory (ARO) 12-m and Submillimeter Telescope (SMT) to identify new interstellar molecules containing NCHOPS and other astrochemically relevant elements, as well as to examine elemental abundance gradients. Phosphorus monoxide (PO) was identified for the first time in the star-forming region Orion-KL through analysis of a 3 mm spectral line survey obtained with the ARO 12-m. By examining the line profile and LSR velocity of PO, the molecule was localized to the Plateau region of Orion-KL, providing additional evidence that shock chemistry plays a role in the formation of phosphorus molecules. Additionally, 3, 2, and 1 mm spectral line surveys were conducted towards the carbon-rich envelope of the AGB star IRC+10216 using both the 12-m and SMT telescopes. These sensitive surveys allowed for the detection of very weak rotational lines, leading to the identification of two new interstellar molecules: SiP, a phosphorus-bearing radical, and FeC, the first metal carbide (in the chemist’s sense) detected in the interstellar medium. Both molecules were found in shell distributions within the envelope of IRC+10216, with formation mechanisms likely tied to shock chemistry. To explore the molecular content of the Outer Galaxy, observations were conducted towards Galactic Edge Clouds using the ARO 12-m and IRAM 30-m telescopes. PO and PN were identified in the Edge Cloud WB89-621, located 22.6 kiloparsecs (kpc) from the Galactic Center. This discovery represents the furthest detection of phosphorus in the Galaxy and confirms the presence of all NCHOPS elements in the Outer Galaxy. Furthermore, c-C3H2 was identified in 20 Edge Clouds with galactocentric distances ranging from 12.9 to 23.5 kpc, and nitric oxide (NO) was identified in 16 of these sources. The abundances of c-C3H2 and NO appear to remain constant with respect to galactocentric distances, suggesting a more widespread distribution of these molecules than previously believed and lending further support to the extension of the Galactic Habitable Zone into the Outer Galaxy

Improve the Understanding of Drylands Water and Ecosystem Responses to Droughts through Data Analysis and Modeling Studies

Drylands include arid, semi-arid, and dry sub-humid regions covering ~41% of global land surface, where long-term precipitation is substantially lower than atmospheric water demands. It supports nearly 2.5 billion people with limited water resources and dominates the trend and interannual variability of the global carbon cycle. Drylands are becoming more vulnerable to frequent and severe water scarcity due to climate change exacerbated by increasing anthropogenic and ecological water demands. The intensified droughts under a warming climate substantially reduce vegetation carbon uptakes and even exacerbate the warming through land-atmosphere interactions. Therefore, it is imperative to investigate, realistically model, and project ecohydrological changes over drylands. Compared to observations, vegetation in most Earth System Models (ESMs) is more susceptible to water anomalies and shows a lower drought resilience. This dissertation aims to understand the discrepancy in vegetation drought responses between ESMs and observations through data analysis and modeling. The first part of this dissertation studies lateral flow movement in ESMs. Due to the computation constraint, ESMs typically only describe vertical soil water movement without considering lateral subsurface flow. I incorporated the hillslope-storage Boussinesq (hsB) scheme into the land model of DOE’s Energy Exascale Earth System Model (ELM) to explicitly represent lateral groundwater movement. I applied this newly developed model over California and found better model performance against ELM through the explicit yet simplified representation of lateral flow along hillslopes. Most importantly, our new model outperforms the default ELM in reproducing the seasonal variations, interannual variabilities, and a declining trend of terrestrial water storage anomaly in California. The better terrestrial water loss associated with lateral flow is primarily through enhanced vegetation drought resilience (e.g., enhanced plant transpiration). However, modeled enhancements of plant transpiration decline with increasing grid size and almost disappear with a grid size of 1°, potentially resulting from unrepresentative climates and unresolved land surface properties on the subgrid scale. The second part of the dissertation investigates the controls of concerted plant and soil hydraulics on the interannual variability (IAV) of vegetation carbon uptakes (GPP) over the central US through multiple model experiments. A land surface model explicitly representing plant hydraulics and groundwater capillary rise with an adequate soil hydraulics well captures the observed GPP IAV. The sensitivity experiments indicate that, without representations of plant hydraulics and groundwater capillary rise or using an alternative soil hydraulics, the land model substantially overestimates the GPP IAV and the GPP sensitivity to water in the central US. This highlights the importance of plant and soil hydraulics to Earth system modeling for projections of future climates over regions that may experience more intense and frequent droughts. The last part of this dissertation explores whether vegetation responses (greening/stomatal closure) to the escalating CO2 concentration and warming exacerbate or ameliorate future runoff yields in the dry western US. Water shortage in the western US is becoming increasingly serious due to increasing socioeconomic demands and climate change. Although previous studies have projected various degrees of runoff changes, they neglect the impact of rising CO2 on runoff projections. To explore the possible role that CO2 may play in the hydrologic cycle, I conducted three experiments with the newly improved Noah-MP land model including vegetation dynamics and plant hydraulics. Consistent with previous studies, the western US tends to be drier toward the end of the 21st Century. CO2-induced leaf area index increases (surface “greening”) contribute considerably to the projected widespread transpiration increases and runoff reductions; however, these changes are nearly compensated by the stomatal closure effect of CO2 on transpiration, leaving the warming effect to remain the major cause to these transpiration and runoff changes. This study suggests that both surface “greening” and stomatal closure effects are important factors and should be considered together in water resource projections. In summary, this dissertation enhances the understanding of water and ecosystem responses to droughts over the drylands in the US

Investigating Volumetric Video Creation and Curation for the Digital Humanities: a White Paper Describing Findings from the Project: Preserving BIPOC Expatriates’ Memories During Wartime and Beyond

This white paper describes the findings from the project, "Preserving BIPOC Expatriates’ Memories During Wartime and Beyond," funded in part by a National Endowment for the Humanities Digital Humanities Advancement Grant.Volumetric video capture technologies offer humanities scholars and other researchers new, immersive ways of engaging with historical and cultural knowledge for research and pedagogical purposes; however, the high cost of this technology and a paucity of expert knowledge in the field have limited its adoption. In particular, volumetric video offers rich new possibilities for recording, preserving, and re-experiencing BIPOC (Black, indigenous, and other people of color) stories in immersive detail, which have been underrepresented in the historical record. This technology is still experimental and is typically limited to specialized labs at large research universities. To democratize the technology and ensure that the potential benefits of this new technology can be realized by digital humanities scholars more broadly, a group of researchers at the University of Arizona and Williams College, in collaboration with technical innovators from the world-renowned volumetric capture studio, VoluCap, GmbH, embarked on a project to explore the challenges and potential benefits of volumetric video capture for BIPOC storytelling. The team traveled to Berlin/Potsdam in June 2023 to visit VoluCap Studios and record several volumetric capture videos, including a video of Mike Russell, who told a story about his father’s experiences as an African-American servicemember during World War II. Recording these videos and observing their processing pipeline allowed us to consider the logistical and data curation challenges of this format. Dr. Bryan Carter, lead-PI on the project, is also director of UArizona’s Center for Digital Humanities, which houses a prosumer-level volumetric capture studio. Comparing the workflows at the Center for DH with what was observed at VoluCap allowed the project team to better understand the challenges and benefits of volumetric capture at different scales and levels of quality. Because volumetric videos are expensive and time consuming to create, an important objective of this project was to examine the preservation and curation challenges associated with the digital objects created through the volumetric capture process. Planning for preservation, access, and reuse of volumetric video assets is essential to realizing their full value. This report describes the creation challenges and pedagogical benefits of volumetric video, as well as preservation and curation challenges.National Endowment for the HumanitiesThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Dominick Argento’s I Hate and I Love: A Comprehensive Analysis for Conductors

Dominick Argento was an American contemporary composer who achieved great fame as a composer of vocal music, especially lyric opera. The theatrical devices in his works make his compositions distinctive, and Argento's use of symbolic motivic cells is one of the main characteristics that drives the narrative structure in his works. Dominick Argento's I Hate and I Love is an intricate choral work in which Argento masterfully blends twelve-tone techniques with traditional harmonic language to convey the complex emotional interplay between love and hate as expressed in the poetry of Gaius Valerius Catullus. In this document, I explore Argento's compositional methods, focusing on his use of symbolic motivic cells, harmonic structures, and dramatic elements that align with the text. By analyzing these techniques, I reveal how Argento's music serves not only as a reflection of Catullus's emotional turmoil but also as an omniscient commentary that adds layers of meaning beyond the explicit text. This research contributes to the broader academic discourse on Argento's choral works, providing deeper insights into his innovative approach to choral composition and his unique integration of serialism with sonorism

Maintaining Values Through Performance in Daily Organizational Work

A small but growing volume of research identifies values work as the activities through which values are performed in organizations. Despite contributing to overall knowledge about values in organizations, this budding stream of values work literature has yet to offer insight into how collectives such as workplace organizations maintain, or consistently enact, important but abstract values through the concrete, shared daily work of members. The ability to maintain multiple important values has performance implications for employees, organizations and the communities served by organizations. To better understand how organizations (i.e., collectives of individuals working together towards shared outcomes in the workplace), maintain multiple important values in concrete daily work, I conducted a seven-month ethnographic case study of a radiation oncology center as its team members created individual treatment plans for cancer patients. I found that in most cases organizations maintain core values by engaging in the values work of framing work projects as standard and delegating them to a set of standard means that habitually enact core values with little additional work or effort. However, in some cases, salient concerns result in framing concerning project work as an exception to the standard. In these instances organizations effortfully enact adjusted means to resolve the concern and protect core values or accommodate additional, important but non-core values