Now showing items 12789-12808 of 19641

    • O'odham rhythms

      Hammond, Michael; Fitzgerald, Colleen Miriam, 1969- (The University of Arizona., 1997)
      Morphology and syllable weight have both been shown to affect stress patterns, but these effects are analyzed in different ways. The theoretical goal of this dissertation is to propose a Optimality Theoretic model to account for how morphology influences stress, and to do this in a way that parallels the influence of weight upon stress. Prince (1990) lays out the W scEIGHT- scTO-S scTRESS P scRINCIPLE, formalizing the principle by which heavy syllables attract stress in quantity-sensitive systems. I argue for the M scORPHEME- scTO-S scTRESS P scRINCIPLE, a constraint that forces morphemes to attract stress in morphological stress systems. The W scEIGHT- scTO-S scTRESS P scRINCIPLE has a counterpart, the S scTRESS- scTO-W scEIGHT P scRINCIPLE, which forces stressed syllables to be heavy. The counterpart of the M scORPHEME- scTO-S scTRESS P scRINCIPLE is the S scTRESS- scTO-M scORPHEME P scRINCIPLE, which forces stressed syllables to belong to morphemes. This accounts for systems where epenthetic vowels resist stress assignment.
    • O-glycopeptide analogues of enkephalin: FMOC-amino acid glycoside synthesis, solid-phase glycopeptide synthesis and optimizations, and pharmacology

      Polt, Robin L.; Mitchell, Scott Allan (The University of Arizona., 1999)
      The synthesis of a series of N-9-fluorenylmethoxycarbonyl (N-FMOC) protected amino acid glycosides is reported. These (1-2)-trans glycosides came directly from Koenigs-Knorr type glycosylations under Hanessian's silver triflate conditions, except for the synthesis of N-acetylgalactosamine FMOC amino acid in which silver perchlorate conditions were used to promote α-glycoside formation. The effect of D-amino acid aglycones was investigated under glucosylation conditions, and a yield dependence on amino protection was seen in the enantiomers of threonine. Due to this match vs. mismatch dichotomy, both O'Donnell Schiff bases and FMOC-amino aglycones were used in the subsequent glycosylation reactions. Glycosides were made using the monosaccharides xylose, mannose, glucose, galactose, N-acetylglucosamine, N-acetylgalactosamine, and disaccharides lactose [galactose-β-(1-4)-glucose], cellobiose [glucose-β-(1-4)-glucose] and melibiose [galactose-α-(1-6)-glucose]. All glycosides were converted to their respective FMOC-amino acid forms for direct use in solid-phase glycopeptide synthesis (SPGPS) using established methodology. A strategy into the synthesis of an FMOC-amino acid trisaccharide of Lewis ˣ (Leˣ) was also investigated in an effort to expand on the established glycoside methodology. Preliminary work with D-glucosamine and L-fucose is reported. Our synthetic rationale was based on retaining the peptide pharmacophore or message sequence constant as DCDCE (D-cys²ʼ⁵-enkephalin) with a serine-glycine tether, and making changes only in the environment of the amino-acid glycoside. Changes in amino acid, amino acid chirality, and in the sugar moiety itself would provide a stereochemical investigation into the requisite orientation and electronics for optimum blood-brain barrier (BBB) penetration, opiate receptor binding, and analgesia. Several glycopeptides were synthesized, and all were purified in both reduced and oxidized forms (if containing cysteine). A highly optimized glycopeptide synthetic strategy has been developed and will be presented and critiqued. Pharmacological analysis involving serum stability studies, BBB-penetration studies, GPI/MVD physicochemical studies and mu/delta-opiate receptor studies were completed on all glycopeptides. SAM-1095, the most potent of the glycopeptides synthesized, was resynthesized on a large scale, and this compound was assessed for in vivo pharmacology, along with the non-glycosylated version SAM-995. Preliminary results demonstrate an analgesic effect similar to that of the narcotic morphine. Assessment of all pharmacology will afford a platform for future SAR-based glycopeptide investigations.
    • Obese Adolescent Females and Actual Behavioral Responses to a Mindful Eating Intervention

      Berg, Judith; Daly, Patricia; Berg, Judith; Moore, Ki; Archbold, Kristen (The University of Arizona., 2013)
      Background: Adolescent obesity has tripled over the last three decades and is associated with an 80 percent risk of adult obesity, hypertension, diabetes, hypercholesterolemia, and decreased life expectancy. Current adolescent obesity medical recommendations include bariatric surgery and appetite suppressants which lower BMI, but present serious health risks. Nutrition and exercise interventions promote health, however, meta-analysis reveal do not lower BMI. Mindful eating, a behavioral skill, reconnecting eating to satiety cues, and has potential as an anti-obesity intervention which lowers BMI, while promoting health. Study Aims: Aim 1: To determine the effect of a mindful eating intervention compared to usual diet and exercise information on BMI of obese female adolescents. Aim 2: To determine if the effect of a mindful eating intervention on BMI of obese female adolescents is sustained over time. Aim 3: To determine the feasibility of conducting a group mindful eating intervention over six weeks for obese adolescent girls in their school setting. Methods: Obesity was measured by Body Mass Index (BMI) = Weight in Pounds / Height in inches x Height in inches x 703. The sample included adolescent females aged 14-17 years with BMI>90th%. Participants were randomized to an intervention group receiving a 6 week mindful eating intervention and a comparison group receiving the usual care of nutrition and physical activity handouts. Participants' BMI was measured at baseline, immediately post intervention and at 4 week follow up assessing intervention effectiveness. Results: ANOVA results demonstrate a statistically significant difference in BMI between the experimental and comparison groups F(1,2)=22.24, p<.001. On average, the experimental group's BMI decreased 0.71, whereas the comparison group's BMI increased by 1.1 over the 6 week intervention. The experimental group's BMI continued to decline at the 4 week follow up. Attrition from the study was 38%, below the 45% set feasibility threshold. A group mindful eating intervention over six weeks for obese adolescent girls was effective in lowering BMI sustained over time is feasible. Teaching the behavioral skill of mindful eating holds great promise for combatting obesity in adolescents. Future study should include a school based intervention with a larger more diverse sample.
    • Obesity in a Southwest Native American tribe: Examination of prevalence, predictive factors, and health risks

      Gray, Norma (The University of Arizona., 1989)
      This research examined obesity in a Southwest Native American Tribe by utilizing data obtained from Indian Health Service regarding individuals who used their health clinics. Sixteen cohorts, ranging in age from 3 to 75 years, were studied across the four years of 1971, 1976, 1981, and 1986. This was an exploratory study designed to investigate four areas related to obesity in this Tribe: (1) Weight and height norms, (2) prevalence of obesity, (3) factors predictive of adolescent obesity, and (4) health risks associated with obesity. The results indicate that this population of Southwest Native Americans generally weigh more and are shorter than national norms, which results in significantly greater BMIs. Norms for weight, height, and Body Mass Index (BMI) were established for all categories during each of the data gathering years of 1971, 1976, 1981, and 1986. Prevalence of obesity based on weight and BMI was established for this time period, also. Predictive factors of adolescent obesity in this Tribe revealed several of children's prior weight variables to be significantly related to adolescent obesity. Whereas, variables related to the children's mothers tended to be nonsignificant. The results indicated two health problems are related to adult obesity in this population: diabetes and cardiovascular disorders. In addition, blood pressure was also related to obesity in that those who were obese tended to have higher systolic and diastolic blood pressures than the nonobese. Several childhood characteristics are seen as indicators that children may need preventive measures in order to reduce the chance of later obesity. Future research is discussed in terms of prospective studies which might provide more information about obesity in this Tribe.
    • Obfuscation of Transmission Fingerprints for Secure Wireless Communications

      Krunz, Marwan; Rahbari, Hanif; Lazos, Loukas; Li, Ming; Krunz, Marwan (The University of Arizona., 2016)
      Our world of people and objects is on the verge of transforming to a world of highly-interconnected wireless devices. Incredible advances in wireless communications, hardware design, and power storage have facilitated hasty spread of wireless technologies in human life. In this new world, individuals are often identified and reached via one or multiple wireless devices that they always carry (e.g., smartphones, smart wearable, implantable medical devices, etc.), and their biometrics identities are replaced by their digital fingerprints. In near future, vehicles will be controlled and monitored via wireless monitoring systems and various physical objects (e.g., home appliance and retail store items) will be connected to the Internet. The list of these changes goes on. Unfortunately, as different aspects of our lives are being immerged in and dependent to wireless devices and services, we will become more vulnerable to wireless service/connection interruptions due to adversarial behavior and our privacy will become more potent to be exposed to adversaries. An adversary can learn the procedures of a wireless system and analyze its stages, and accordingly, launch various attacks against the operations of the system or the privacy of the people. Existing data confidentiality and integrity services (e.g., advanced encryption algorithms) have been able to prevent the leakage of users' messages. However, in wireless networks, even when upper-layer payloads are encrypted, the users' privacy and the operation of a wireless network can be threatened by the leakage of transmission attributes at the physical (PHY) layer. Examples of these attributes are payload size, frequency offset (FO), modulation scheme, and the transmission rate. These attributes can be exploited by an adversary to launch passive or active attacks. A passive attacker may learn about the interests, sexual orientation, political views, and patentable ideas of the user through analyzing these features, whereas an active attacker exploits captured attributes to launch selective packet jamming/dropping and disrupt wireless services. These call for novel privacy preserving techniques beyond encryption. In this dissertation, we study the vulnerability of current wireless systems to the leakage of transmission attributes at the PHY layer and propose several schemes to prevent it. First, we design and experimentally demonstrate with USRPs an energy-efficient and highly disruptive jamming attack on the FO estimation of an OFDM system. OFDM is the core multiplexing scheme in many modern wireless systems (e.g., LTE/5G and 802.11a/n/ac) and is highly susceptible to FO. FO is the difference in the operating frequencies of two radio oscillators. This estimation is done by the receiver using the publicly-known frame preamble. We show that the leakage of FO value via the preamble can facilitate an optimally designed jamming signal without needing to know the channel between the transmitter and the legitimate receiver. Our results show that the jammer can guarantee a successful attack even when its power is slightly less than the transmitter's power. We then propose four mitigation approaches against the proposed FO attack. Next, we consider certain transmission attributes that are disclosed via unencrypted PHY/MAC headers. Example of these attributes are payload size, transmission rate, and MAC addresses. Beyond unencrypted headers, the adversary can estimate the frame size and transmission rate through identifying the payload's modulation scheme and measuring the transmission time. To prevent the leakage of these attributes, we propose Friendly CryptoJam scheme, which consists of three components: First, a modulation-aware encryption scheme to encrypt the headers. Second, an efficient modulation obfuscation techniques. Specifically, the proposed modulation obfuscation scheme embeds the modulation symbols of a frame's payload into the constellation of the highest-order modulation scheme supported by the system. Together with effective PHY/MAC header encryption at the modulation level, the proposed obfuscation scheme hides the transmission rate, payload size, and other attributes announced in the headers while avoiding any BER performance loss. Compared with prior art, Friendly CryptoJam enjoys less complexity and less susceptibility to FO estimation errors. The third component is a novel PHY-level identification method. To facilitate PHY/MAC header encryption when a MAC layer sender identifier cannot be used (e.g., due to MAC address encryption), we propose two preamble-based sender identification methods, one for OFDM and one for non-OFDM systems. A sender identifier is special message that can be embedded in the frame preamble. The extent of the applications of our embedding scheme goes beyond identifier embedding and include embedding part of the data frame, the sender's digital signature, or any meta-data that the sender provides. Our message embedding method can further be used to mitigate the FO estimation attack because the jammer can no longer optimize its jamming signal with respect to a fixed preamble signal. In addition, we considered friendly jamming technique in a multi-link/hop network to degrade the channels of the eavesdroppers and prevent successful decoding of the headers, while minimizing the required jamming power by optimally placing the friendly jamming devices.
    • Object and spatial memory in fetal alcohol syndrome: An assessment of hippocampal dysfunction.

      Uecker, Anne Cantalupo.; Nadel, Lynn; Rosser, Rosemary; Copple, Peggy; Kaszniak, Alfred W.; McNaughton, Bruce (The University of Arizona., 1993)
      Fetal alcohol syndrome (FAS), a leading cause of mental retardation, was initially described in the United States only twenty years ago. Because it is likely that fetal alcohol exposure contributes substantially to the heterogeneously-grouped learning disabled population, it is worthwhile to review the known cognitive and neurobiological bases of this syndrome, and to test promising neuropsychological hypotheses. For example, animal models of FAS indicate neuroanatomical and behavioral deficits attributable to dysfunction of the hippocampus, a neural structure important in learning and especially spatial memory. In addition, although humans with FAS have demonstrated difficulty with nonverbal problems that are spatial in nature, no specific tests of hippocampal dysfunction have been administered. Thus, fifteen children (x age = 9.8 ± 2.32) with alcohol related birth defects (ARBD), and 15 control children (x age = 9.7 ± 2.40) were tested on several spatial and object memory tasks. These tasks were administered in (1) a small-scale desk-work type environment, and (2) a large-scale environment designed to parallel animal work. The spatial tasks were presumed to be indicators of intact hippocampal functioning, but the object memory tasks were not. As expected, individuals with ARBD consistently demonstrated a deficit spatial memory performance. There was never a significant difference on an immediate object recall task, but the children with ARBD tended "to forget" more objects after a delay in two of the three experiments. Previous research emphasizes the role of the hippocampus in spatial memory (Morris, Garrud, Rawlins, & O'Keefe, 1982) as well as in visually-mediated delayed object recall. Left neocortical structures that subserve immediate object recall appear to be relatively intact. Visuospatial descriptive testing indicated a further disturbance in nonverbal information processing that could involve such neuroanatomical structures as the frontal lobe, parietal cortex, basal ganglia, corpus callosum, and cerebellum. Further studies that address intact vs. deficit performance in children with ARBD could illuminate some specific structural-functional attributes in the brains of children. Defining the neurodevelopmental role of the hippocampus in learning and memory is a priority to be accomplished.
    • Object-oriented remote consultation and diagnosis in global PACS using multi-thread Java

      Martinez, Ralph; Yu, Yuan-Pin, 1967- (The University of Arizona., 1996)
      Designing an integrated portable, object-oriented, real-time multimedia remote consultation and diagnosis (RCD) system for Global PACS has been a research challenge for the past years. There are many specialties in the medical environment, generating multimedia information. During a diagnosis, physicians need to refer to other cases, medical references and other physicians. Continuing medical education and exchanging experience among physicians are critical items to improve the quality of diagnosis. In clinical telemedicine, there is a need to have a viewing workstation serving different purposes in an heterogeneous medical environment. This viewing workstation must be portable and flexible to meet the needs of various medical specialties. The objective of this research is to perform an object oriented analysis and design for a Global PACS environment and implement in Java. In this research, the Java programming environment is used. Object-oriented Java is portable across several platforms. It has a Graphics User Interface (GUI) package, a network package, a Web package, a security package and a thread package. In this research, common objects are defined and implemented for the RCD system. The GUI part can be customized to fit different purposes. This development is performed in the context of a Global PACS environment. The Global PACS RCD has three major program components: the diagnosis component, the education component and management component. These components all share the same common objects and methods. The software modules are designed to run as stand-alone Java applications and as applets in the Java-enabled Web browsers. Physicians can use it to do diagnosis of store and forward cases on-line or off-line in a Global PACS. Students can check out cases and turn in their diagnosis from the Web browser. A system manager can manage the RCD workstations and Global PACS database from the same workstation. Performance tests of the object oriented Java software show a performance equal or better to previous RCD implementation in Global PACS.
    • The Objective Grading of Original Unaccompanied Four-Mallet Solo Vibraphone Literature

      Weinberg, Norman; Hewitt, Jeffrey Allen; Weinberg, Norman; Reid, Edward; Thomas, Kelly (The University of Arizona., 2014)
      An important resource in many areas of music is the availability of standardized graded databases of literature for solo instruments. These databases provide a progression of technical abilities that help musicians follow a proper path in developing new skills. Currently in the area of percussion, there are no graded databases for solo vibraphone literature. While there are several sources that contain subjective graded music lists, none of these sources have a standardized approach in defining each of their difficulty levels, and this creates contradicting information for particular pieces. The goal of this research is to present the first standardized and systematic approach to grading the difficulty levels of vibraphone literature. Influenced by pianist Jane Magrath's reference guide of piano teaching literature and percussionist Julia Gaines' research project on marimba repertoire, this research is modeled on Gaines' objective analysis document used to grade marimba literature with ten different levels of difficulty. With the exception of dampening and pedaling, all of the technical aspects required for playing the vibraphone remain the same as the marimba. Because musical considerations are subjective in nature, only the quantifiable technical considerations are used for grading each work in an objective manner. The technical difficulty of original unaccompanied four-mallet solo vibraphone literature is assessed through the analysis of stroke speed, interval size, wrist turns, manual changes, independence, dampening, and pedaling. Each piece's grade will be classified based on the highest level of technical difficulty found in the music. The selection of vibraphone literature for this research comes from pieces found on prescribed state music lists and university handbook recommendation lists. Annotations are included to describe the pieces that are particularly mislabeled, and a discussion regarding the performance challenges that each piece presents are offered. Three annotations from each of the ten difficulty levels contain a justification based on the results recorded in the analysis document. With an extensive graded database containing over one hundred seventy vibraphone pieces listed in the appendix, this resource will assist percussion students and educators in selecting appropriate vibraphone literature to study and perform within a proper progression from one work to another.
    • Objective Measures of Tropical Cyclone Intensity and Formation from Satellite Infrared Imagery

      Ritchie, Elizabeth A; Tyo, J Scott; Pineros, Miguel F.; Ritchie, Elizabeth A; Tyo, J Scott; Gehm, Michael (The University of Arizona., 2009)
      This document proposes an objective technique to estimate the intensity and predict the formation of tropical cyclones using infrared satellite imagery. As the tropical cyclone develops from an unstructured cloud cluster and intensifies the cloud structures become more axisymmetric around an identified reference point or center. This methodology processes the image gradient to measure the level of symmetry of cloud structures, which characterizes the degree of cloud organization of the tropical cyclone.The center of a cloud system is calculated by projecting and accumulating parallel lines to the gradient vectors. The point where the highest number of line intersections is located pinpoints a common point where the corresponding gradients are directed. This location is used as the center of the system. Next, a procedure that characterizes the departure of the weather system structure from axisymmetry is implemented. The deviation angle of each gradient vector relative to a radial line projected from the center is calculated. The variance of the set of deviation angles enclosed by a circular area around the center describes the axisymmetry of the system, and its behavior through time depicts its dynamics. Results are presented that show the time series of the deviation angle variances is well correlated with the National Hurricane Center best-track estimates.The formation of tropical cyclones is detected by extending the deviation-angle variance technique, it is calculated using every pixel in the scene as the center of the cloud system. Low angle variances indicate structures with high levels of axisimmetry, and these values are compared to a set of thresholds to determine whether a cloud structure can be considered as a vortex. The first detection in a sequence indicates a nascent storm. It was found that 86% of the tropical cyclones during 2004 and 2005 were detected 27 h on average before the National Hurricane Center classified them as tropical storms (33kt).Finally, two procedures to locate the center of a tropical cyclone are compared to the National Hurricane Center best-track center database. Results show that both techniques provide similar accuracy, which increases as the tropical cyclone evolves.
    • Objects of Desire: Feminist Inquiry, Transnational Feminism, and Global Fashion

      Soto, Sandra; Verklan, Elizabeth; Soto, Sandra; Joseph, Miranda; Luibhéid, Eithne; Nguyen, Mimi (The University of Arizona., 2017)
      This dissertation examines the conventions used to frame and represent sweatshops in and to the U.S. Employing qualitative research methods this dissertation examines U.S. anti-sweatshop discourse, analyzing how the sweatshop and the sweatshop worker are made into exceptional objects of inquiry, and considers what kinds of truths and subjects are garnered from them. This dissertation argues that U.S. anti-sweatshop discourse frames sweatshops as an inherently foreign problem, and that this framing contributes to U.S. exceptionalism and savior ideology. This framing positions U.S. subjects as the primary agents of change whose relation to sweatshops is crucial to their eradication, and renders causal blame upon the racialized poor within the U.S. I argue that this framing undergirds the proliferation of new ethical markets that reproduce dislocation, dispossession, and displacement within U.S. borders via retail gentrification. Ultimately, this dissertation asks what truths are made possible through a mobilizing discourse whose foundational premise is contingent on the imagery of the sweatshop and the sweatshop worker.
    • OBSERVABLE SINGLE PARTICLE STATES IN QUANTUM FIELD THEORY

      Kennedy, Larry Zane, 1938- (The University of Arizona., 1968)
    • OBSERVATION OF CHAOS IN A HYBRID OPTICAL BISTABLE DEVICE (PERIOD-DOUBLING).

      Hopf, Fred; DERSTINE, MATTHEW WILLIAM. (The University of Arizona., 1985)
      An analog of an optically bistable device made constructed from both optical and electronic components is used to study chaos. This hybrid optically bistable system has a delay in the feedback so that the response time of the electronics is much faster than the feedback time. Such a system is unstable and shows pulsations and chaos. The character of the pulsations change as the gain of the amplifier or the input laser power is increased. These changes make up the period doubling route to chaos. Not all of the waveforms of an ideal period doubling sequence are observed. This truncation of the period-doubling sequence in the device is investigated as a function of the noise present in the system. Increasing the noise level decreases the number of period doublings observed. In the chaotic regime waveforms other than those predicted are observed. These waveforms are the frequency-locked waveforms seen in an earlier experiment which we find to be modified versions of the typical period-doubled waveforms. The transitions between these waveforms are discontinuous, and show hysteresis loops. By the introduction of an external locking signal, we are able to stabilize waveforms in the neighborhood of the discontinuous transitions. By so doing we show that the transitions among the branches are due to their lack of stability. The transitions are thus not strictly first-order nonequilibrium phase transitions, since in that case the branches cease to exist at the transition point. Since the path to chaos is nonunique, the types of chaos that are observable are also nonunique. To suggest a way to distinguish between different types of chaos and also to provide a tool for the study of chaos in other systems, we propose an operational test for chaos which leads to a straightforward experimental distinction between chaos and noise. We examine this test using the hybrid device to show that the method works. The test involves repeated measurement of the initial transient of a system whose initial condition is fixed. This method could be used to determine the existence of chaos in faster optical systems.
    • Observation of problem-solving in multiple intelligences: Internal structure of the DISCOVER assessment checklist

      Maker, C. June; Seraphim, Catherine Kerry Michel, 1960- (The University of Arizona., 1997)
      The primary purpose of this study was to assess certain aspects of the internal structure of the DISCOVER assessment checklist to determine its construct validity. A secondary purpose was to assess gender differences in identifying giftedness using the assessment. The sample of this study consisted of 368 participants from kindergarten, fourth, fifth, and sixth grade levels divided into three subsamples. Participants were from two culturally diverse populations: Navajo Indians and Mexican-Americans. The methodology consisted of correlational analyses and chi-square tests. Separate, but identical analyses were conducted on each subsample. Three questions guided this study: (a) What is the relationship between observers' ratings of participants' problem-solving ability in one activity and their rating of participants in the other activities? (b) What items characterize each of the four rating categories? and (c) What are the gender differences occurring when using the assessment? The results of this study showed low and non significant inter-rating correlations, indicating high discriminant validity of the checklist. Significant, but low to moderately high inter-rating correlations were found between the Storytelling and Storywriting activities across subsamples. R-squared analyses revealed low percentages of variance accounted for, indicating low convergent validity of the checklist. Moreover, a pattern of higher percentages of item checks was found for higher ratings, indicating that observers checked items at a higher frequency rate for participants given higher ratings. Only items characterizing the "Definitely" category were possible to identify because all items represent superior problem-solving skills, thus were mostly checked for participants who demonstrated superior problem-solving processes or products. Items with zero frequencies were identified as well. Chi-square tests for gender by activity revealed significant gender differences in two activities. In Pablo°ler, a significantly higher number of sixth grade boys were rated "Definitely" and in Storytelling, a significantly higher number of fourth and fifth grade girls were rated "Definitely". No significant gender differences were found for any other activity across subsamples. Similarly, no significant overall gender differences were found across subsamples for gifted participants, indicating that equal proportions of males and females are identified through the use of the DISCOVER assessment.
    • OBSERVATION OF THE INFRARED SPECTRA OF THE DEUTERATED TRIATOMIC HYDROGEN MOLECULAR TONS: H₂D⁺, HD₂⁺, and D₃⁺

      Wing, William; SHY, JOW-TSONG. (The University of Arizona., 1982)
      The infrared vibrational-rotational spectra of the deuterated triatomic hydrogen molecular ions, H₂D⁺, HD₂⁺, and D₃⁺ have been observed with the Doppler-tuned ion-beam laser spectroscopic method with collision detection. Triatomic hydrogen molecular ions are produced in a coaxial electron-impact ion source. Next, the ions are accelerated and formed into a beam of several keV energy, which is then intercepted at a small angle by a frequency-stabilized CO laser beam. The energy of the ion beam is adjusted to Doppler-shift an ion transition into resonance with a nearby laser line. On resonance, the laser light stimulates the transition to take place. If the resonating states differ in population, the laser-induced transition produces a net population transfer. The occurrence of population transfer is detected by monitoring the transmission of the ion beam through a gas target after laser interaction. The transmission through the target is dependent upon the ion beam population distribution and, therefore, the laser-induced transition can be detected by detecting the change of the transmission of the ion beam. A mass analyzer before the target gas facilitates the mass identification of the observed transitions. We have measured 45 D₃⁺ transition frequencies, 9 H₂D⁺ transition frequencies, and 31 HD₂⁺ transition frequencies, all between 1650 and 2000 cm⁻¹, to better than ±0.0005 cm⁻¹ or ±0.3 ppm. The identifications of the quantum numbers are still in progress. This study should greatly help the search of H₃⁺ and H₂D⁺ ions in interstellar medium.
    • OBSERVATION OF THE INFRARED SPECTRUM OF THE HELIUM-HYDRIDE MOLECULAR ION

      Wing, William H.; Tolliver, David Edward (The University of Arizona., 1980)
      This dissertation describes the first high-precision observation of the infrared spectrum of the helium hydride molecular ion HeH⁺. The frequencies of five vibrational-rotational transitions in the range 1700-1900 cm⁻¹ in the X¹Σ⁺ ground electronic state of ⁴HeH⁺ have been measured to ±0.002 cm⁻¹ (±1 ppm). The Doppler tuned ion beam laser spectroscopic method was used in making the measurements: In a region of constant electrostatic potential, an HeH⁺ ion beam of several keV energy is intercepted at a small angle by a beam from a carbon monoxide infrared gas laser. The energy of the ion beam is adjusted to Doppler-shift an ion transition into resonance with a nearby laser line. On resonance the laser light stimulates transitions to take place. If the resonating states differ in population, the laser-induced transitions produce a net population transfer. The occurrence of population transfer is detected by monitoring the transmission of the ion beam through a gas target downstream from the laser beam interaction region. The transmission through the target is dependent upon the ion beam vibrational-state population distribution and therefore is sensitive to changes in the population distribution, because the cross-section for charge-exchange neutralization of an incident ion is dependent upon the vibrational state of the ion. The current interest in molecular ions in general, and in HeH⁺ in particular, is explained. The existing theory of the structure of HeH⁺ is summarized and a comprehensive listing of theoretical treatments of the structure of HeH⁺ is given. The meager previous experimental work on HeH⁺ is reviewed. The principles of the Doppler tuned ion beam laser resonance method are discussed and the experimental apparatus used is described in detail. The acquisition and analysis of the data is described and the results are compared with the best existing theoretical predictions of the transition frequencies. The present experimental values (given by D. E. Tolliver, G. A. Kyrala, and W. H. Wing, Phys. Rev. Lett. 43, 1719) for the measured transitions are (with the corresponding values calculated by D. L. Bishop and L. M. Cheung, J. Mol. Spectrosc. 75, 462, given in parentheses): (v,J)=(1,11)↔(0,12), 1855.905 cm⁻¹ (1856.152 cm⁻¹); (1,12)↔(0,13), 1751.971 cm⁻¹ (1752.198 cm⁻¹); (2,8)↔(1,9), 1896.992 cm⁻¹ (1897.139 cm⁻¹); (2,9)↔(1,10), 1802.349 cm⁻¹ (1802.492 cm⁻¹); and (2,10)↔(1,11), 1705.543 cm⁻¹ (1705.684 cm⁻¹). It is seen that the present experimental values deviate from the theory by typically 0.2 cm⁻¹, and are two orders of magnitude more precise than the theoretical values.
    • Observational and Experimental Astrochemistry: A High Resolution Gas Phase Study of Metal Containing Species in the Laboratory and Circumstellar Envelopes of Stars

      Ziurys, Lucy M.; Pulliam, Robin L.; Monti, Oliver; Kukolich, Stephen; Woolf, Neville; Beiging, John; Ziurys, Lucy M. (The University of Arizona., 2011)
      It was once thought that molecules in the interstellar medium (ISM) would be destroyed in the harsh surroundings and conditions of space, and therefore unobservable by radio techniques. However, it is now understood that the chemistry of the ISM is vast and complex. The question still remains as to just how complex is this chemistry. Much is clearly still not understood. This dissertation presents work on the study of metal compounds and cations in the circumstellar envelopes of oxygen- and carbon-rich asymptotic giant branch (AGB) and supergiant stars. Laboratory studies were also conducted on several transition metal compounds of interstellar interest, some with high spin and orbital angular momentum states. Work has been completed to confirm the detection of the debated metal cyanide KCN in the carbon-rich AGB star IRC+10216. KCN joins the list as the fifth interstellar metal cyanide/isocyanide detected in this source. In addition, preliminary results on the search for TiO are presented towards the oxygen-rich supergiant star, VY CMa. To further understand the evolutionary processes of carbon- and oxygen-rich stars, a survey of HCO⁺ was taken towards the carbon star IRC+10216, the oxygen-rich AGBs TX Cam, IK Tau, and W Hya and the oxygen-rich supergiant NML Cyg. While HCO⁺ was detected towards all of these sources, the results vary. The outflow of NML Cyg proves to be asymmetric and further study is necessary. The emission from W Hya is significantly narrower than the other sources. The abundances of HCO⁺ in circumstellar gas increases inversely with mass-loss rate and ion-molecule chemistry appears to influence the chemistry of evolved circumstellar envelopes. To understand species in space with more confidence, a laboratory search for several 3d transition metal species of astrochemical interest was conducted in the laboratory: HZnCl (X¹∑⁺), ZnO (X¹∑⁺ and a³Πᵢ), ZnCl (X²∑⁺), TiS (X³Δᵣ) and CrS (X⁵Πᵣ). All of the molecules have been observed for the first time with high resolution gas phase rotational spectroscopy and the work on ZnO was the first gas-phase study of this molecule. Synthesis of the species required exotic production methods, including use of a DC discharge to produce all zinc species. By studying the rotational spectra, rest frequencies were determined that will be beneficial for future astronomical searches.
    • Observational and Theoretical Cosmology with Novel Statistical Methods

      Melia, Fulvio; Leaf, Kyle Kevan; Sandhu, Arvinder; Su, Shufang; Rafelski, Johann; Fleming, Sean (The University of Arizona., 2019)
      The standard ΛCDM model of the universe has been shown to be consistent with a wide range of astronomical observations, including many properties of the cosmic microwave background (CMB). However, the model has significant tension with an increasing set of measurements, ranging from determinations of the Hubble Constant to the angular correlation function of the CMB. This motivates revisions to ΛCDM, or the consideration of alternative models (or even entirely new physics). The Rh=ct universe is an alternative FLRW cosmology that has thus far performed very well in describing a wide range of astronomical observations. In this dissertation, I present a sequence of tests of cosmology. These tests are designed to determine whether the Rh=ct universe performs better than the standard model in accounting for the considered data. First, I show the development of a two-point diagnostic to compare a model’s predictions with observations. This diagnostic is applied to passively evolving elliptical galaxies (cosmic chronometers) and the Hubble diagram as constructed using HII galaxies. Second, I make use of relative likelihoods with strongly-lensed galaxies to constrain standard ΛCDM and an alternative dark matter parameterization (wCDM). These model fits are then compared with the Rh=ct universe by means of several information criteria. Each of the direct comparisons using existing data favor the Rh=ct universe over standard ΛCDM to different degrees, warranting further research to determine whether it accurately describes the Universe. Finally, I present a theoretical prediction of the number of z>6 blazars that will be detectable by upcoming surveys by the Square Kilometer Array (SKA). This prediction is entirely phenomenological, based on spectral energy distribution (SED) measurements of known blazars. The predictions for the number of blazars detectable by SKA between these models are incompatible, such that either the Rh=ct universe or ΛCDM will be strongly preferred by the surveys.
    • OBSERVATIONAL ASPECTS OF CEPHEID EVOLUTION

      Havlen, Robert James, 1943- (The University of Arizona., 1970)
    • An observational comparison of mercury and the moon

      Hunten, Donald; Sprague, Ann Louise (The University of Arizona., 1990)
      Observations of the neutral sodium (Na) and neutral potassium (K) atoms in the tenuous atmospheres of the Moon and Mercury have been made, analyzed and interpreted. An atmospheric number density of ∼300 times more Na and ∼100 times more K are observed at Mercury than at the Moon. This is not consistent with a meteoritic source for these constituents unless losses and recycling are very different. Potassium observations in the lunar atmosphere indicate fewer accommodated atoms than expected from thermalization of the extended component through gas-surface interactions. A mechanism for redistributing the thermal and non-thermal populations is presented. Thermal infrared observations between 7.5 and 12.5 μm have been made at both bodies in an attempt to gain understanding of the relationship of the surfaces to the alkali atmospheres. Mercury has been found to have a surface composition at three locations more felsic than that of the lunar south-polar highlands. Spectral indications of high alkali feldspar have been observed. One mafic location on Mercury's surface has been determined. Calculations using a grain-boundary and regolith diffusion model have shown that the differences in abundances of Na and K and the ratios of Na/K at both bodies can be explained by a supply of atoms diffusing upward through the sub-surface materials over geologic time. Enhancements in K seen at the longitude of Caloris and the antipodal point of up to five (5) and four (4) respectively, point to a sub-surface source for at least part of the tenuous alkali atmosphere at Mercury.
    • Observational Constraints on the Structure and Evolution of Quasars

      Bechtold, Jill; Kelly, Brandon Charles; Bechtold, Jill; Fan, Xiaohui; Dave, Romeel; Walker, Christopher; Rudnick, Gregory (The University of Arizona., 2008)
      I use X-ray and optical data to investigate the structure of quasars, and its dependence on luminosity, redshift, black hole mass, and Eddington ratio. In order to facilitate my work, I develop new statistical methods of accounting for measurement error, non-detections, and survey selection functions. The main results of this thesis follow. (1) The statistical uncertainty in the broad line mass estimates can lead to significant artificial broadening of the observed distribution of black hole mass. (2) The z = 0.2 broad line quasar black hole mass function falls off approximately as a power law with slope ~ 2 for M_{BH} > 10^8 M_{Sun}. (3) Radio-quiet quasars become more X-ray quiet as their optical/UV luminosity, black hole mass, or Eddington ratio increase, and more X-ray loud at higher redshift. These correlations imply that quasars emit a larger fraction of their bolometric luminosity through the accretion disk component, as compared to the corona component, as black hole mass and Eddington ratio increase. (4) The X-ray spectral slopes of radio-quiet quasars display a non-monotonic trend with Eddington ratio, where the X-ray continuum softens with increasing Eddington ratio until L / L_{Edd} ~ 0.3, and then begins to harden. This observed non-monotonic trend may be caused by a change in the structure of the disk/corona system at L / L_{Edd} ~ 0.3, possibly due to increased radiation pressure. (5) The characteristic time scales of quasar optical flux variations increase with increasing M_{BH}, and are consistent with disk orbital or thermal time scales. In addition the amplitude of short time scale variability decreases with increasing M_{BH}. I interpret quasar optical light curves as being driven by thermal fluctuations, which in turn are driven by some other underlying stochastic process with characteristic time scale long compared to the disk thermal time scale. The stochastic model I use is able to explain both short and long time scale optical fluctuations.