Now showing items 7821-7840 of 39116


      Clabby, John Francis (The University of Arizona., 1979)
    • D/H Ratio in IRC+10216

      Ziurys, Lucy M.; Schulte, Sean (The University of Arizona., 2014)
    • D230N-Tm Induced Dilated Cardiomyopathy and the Role of Fetal cTnT Isoform Switching in Modulating Disease Severity

      Tardiff, Jil C.; Lynn, Melissa L.; Tardiff, Jil C.; Konhilas, John P.; Granzier, Hendrikus; Lynch, Ronald; Harris, Samantha (The University of Arizona., 2017)
      In 1980, the World Health Organization task force first sought to define and classify cardiomyopathies. They defined cardiomyopathies as "heart muscle diseases of unknown cause" with three main classifications including: hypertrophic cardiomyopathy (HCM), dilated cardiomyopathy (DCM), and restrictive cardiomyopathy [1]. Over the next three decades it became patently obvious that this simple definition was not sufficient to describe the complex heterogeneity of diseases present in the patient population. More robust definitions were necessary for mechanistic links to be established and meaningful therapeutics to be developed. Since then the accepted definition of a cardiomyopathy has evolved and the classifications have greatly expanded. The most recent definition from the American Heart Association Council on Clinical Cardiology states: Cardiomyopathies are a heterogeneous group of diseases of the myocardium associated with mechanical and/or electrical dysfunction that usually (but not invariably) exhibit inappropriate ventricular hypertrophy or dilatation and are due to a variety of causes that frequently are genetic. Cardiomyopathies either are confined to the heart or are part of generalized systemic disorders, often leading to cardiovascular death or progressive heart failure–related disability [2]. This latest definition (2006) reflects the growing recognition of molecular genetics as a key factor in the development of cardiomyopathies and highlights the ever-growing complexity of disease classification. Today the genetic basis of HCM and DCM is widely recognized yet our understanding of the precise mechanisms underlying the disease remains unclear. To add to this disconnect, by the time patients become symptomatic, pathology has progressed past the initial phase, where meaningful treatment could occur, to advanced end-stage pathology. By this time often the only treatment options available become "blunt sword" therapeutics that are non-specific and used primarily for symptom management. In fact, over the last 3 decades there has been a marked decline in the innovation of cardiovascular pharmaceuticals owed partially to the vast complexity of disease presentation and progression [3]. In this dissertation, I will focus on a genetic sarcomeric DCM caused by a mutation in alpha-tropomyosin (Tm). Using novel accurate mouse models as a tool we will define the mechanism by which it leads to disease, investigate how disease severity due to the mutation is modified in an age-dependent manner, and examine what this mechanism could mean in the larger picture of cardiomyopathic disease progression. I hope to convince you that by using accurate models of this DCM at multiple levels of biological complexity to tease out the precise mechanisms of disease we can establish meaningful genotype-phenotype relationships that could lead to the development of specific novel therapeutics.
    • The daily accounts of an internship in probation as performed at the Pima County Juvenile Court Tucson, Arizona, February 1, 1960 to April 5, 1960

      Brotherton, William L. (The University of Arizona., 1960)
      Diary in lieu of thesis (M.P.A. - Public Administration) -- University of Arizona.
    • Daily and seasonal pollination cycles of various grasses

      Milner, Grant F., 1934- (The University of Arizona., 1964)
    • Daily estimation of local evapotranspiration using energy and water balance approaches

      Rim, Chang-Soo.; Gay, Lloyd W.; Lehman, Gordon S.; Guertin, Phillip D.; Contractor, Dinshaw N.; Lansey, Kevin E. (The University of Arizona., 1995)
      Meteorological and environmental (i.e. soil water content) data measured from semiarid watersheds (Lucky Hills and Kendall) during the summer rainy and winter periods were used to study the interrelationships between variables, and to evaluate the effects of variables on the daily estimation of actual evapotranspiration (AET). The relationship between AET and potential evapotranspiration (PET) as a function of an environmental factor was the major consideration of this research. The relationship between AET and PET as a function of soil water content as suggested by Thornthwaite-Mather, Morton and Priestley-Taylor was studied to determine its applicability to the study area. Furthermore, multiple linear regression (MLR) analysis was employed to evaluate the order of importance of the meteorological and soil water factors involved. Finally, the information gained was used for MLR model development. The results of MLR analysis showed that the combined effects of available energy, soil water content and wind speed were responsible for 77 % of the observed variations in AET at Lucky Hills watershed and 70 % at Kendall watershed during the summer rainy period. The analyses also indicated that the combined effects of available energy, vapor pressure deficit and wind speed were responsible for 70 % of the observed variations in AET at Lucky Hills watershed and 72 % at Kendall watershed during the winter period. However, the test results of three different approaches, using the relationships between AET and PET as a function of soil water content indicated some inadequacy. The low correlation between PET, AET, and soil moisture conditions raised some doubt concerning the validity of methods developed elsewhere, and indicated the effects of energy availability on the relationship between PET, AET, and soil water content regardless of the soil water condition. In contrast, agreement between observed AET and estimated AET from MLR models during the summer rainy and winter periods at both watersheds indicated that MLR models can give reasonable estimates of AET, at least under the climatic conditions in which the formulae were developed.
    • Daily Processes in Romantic Relationships

      Curran, Melissa; Totenhagen, Casey J.; Ridley, Carl; Butler, Emily; Serido, Joyce (The University of Arizona., 2011)
      My goal was to examine how experiences and behaviors of individuals and their romantic partners impact relationships on a daily basis. I conducted three separate but empirically and conceptually related studies. For all three papers, the sample was both members of heterosexual romantic relationships (N = 164 couples, 328 individuals) who completed measures each day for seven days. The papers were informed by tenets from interdependence theory and the conservation of resources model. The main purpose of the first paper was to examine a set of relational constructs (i.e., satisfaction, commitment, closeness, conflict, ambivalence, maintenance, and love) to determine which constructs fluctuated daily. All seven relational constructs showed significant within-person variability and were thus appropriate for further daily investigation. With this information, the next step was to understand how to foster positive relationships by examining what daily experiences were associated with those fluctuations. In the second paper I examined whether daily hassles and uplifts were associated with same-day and next-day feelings about the relationship. For same-day effects, I found that hassles were associated with decreased positivity and increased negativity about relationships, whereas uplifts were largely associated with increased positivity. I also found interactions between hassles and uplifts, suggestive of "blunting" effects whereby the positive effects of uplifts were nullified by high levels of hassles. For the next-day effects, I unexpectedly found that uplifts were associated with decreased positive relational constructs on the next day, possibly indicating a return to homeostatic levels. In the third paper, I moved to a more explicit examination of dyadic processes by examining both actor and partner effects and focusing on the role of relational sacrifices, or the daily changes individuals make for the sake of their romantic parnters. I expected that sacrifices would be beneficial for positive relationship quality, particularly on days characterized by low (versus high) hassles. I found support for these expectations with regards to actor, but not partner effects. Overall implications are that the everyday things that individuals experience (e.g., hassles and uplifts) and enact (e.g., sacrifices) are important considerations in fostering less negative and more positive romantic relationships.
    • The daily religious life in England of the early 17th century

      Snyder, William Henry, 1911- (The University of Arizona., 1935)
    • Daily stressors and memory failures in a naturalistic setting: Findings from the normative aging study

      Almeida, David M.; Neupert, Shevaun D. (The University of Arizona., 2003)
      The role of stress in memory functioning has typically been examined in the laboratory with biological indicators of stress (i.e., stress hormones) and cognitive tests. These studies have generally found a negative association between stress and cognitive performance; that is, people who have higher levels of stress hormones tend to have poorer cognitive performance. The present investigation sought to test this relationship in a naturalistic setting by examining daily stressors and memory failures via a daily diary paradigm. Further, age differences in reactivity (the likelihood of reporting a memory failure when a stressor is experienced) were examined. The primary source of data was the most recent wave of the Normative Aging Study (NAS), a longitudinal study that began in 1961 to examine normal aging processes. One hundred twenty-one adults (69 men, 52 women, age range 44-89) participated in the present study and answered questions regarding their daily stressors and memory failures for eight consecutive evenings. Results from Hierarchical Linear Modeling (HLM) analyses indicated that on days when people experience stressors, they were more likely to also report memory failures compared to stressor-free days. Although age differences in reactivity were not apparent when examining the total frequency of stressors and memory failures, some age differences emerged when looking more specifically at stressor and memory failure type. This study did not directly test the underlying physiological processes of stressors and memory failures, but the results found in a naturalistic setting lend ecological validity to findings that have been previously restricted to the laboratory. Directions for future research (e.g., combining laboratory and naturalistic measures, sampling a wider age range, implementing other sampling techniques, etc.) are discussed.
    • Dairy Processing Plant Production

      Ravaglia, Marco; Dinh, Justin; Frandsen, Michelle; Garcia, Alyssa (The University of Arizona., 2011-05)
    • Damage accumulation in random loads.

      Ortiz, Keith; Perng, Horng-Linn.; Wirsching, Paul H.; Kececioglu, Dimitri (The University of Arizona., 1989)
      An equivalent constant amplitude fatigue loading (Miner's stress) is developed for stationary random amplitude loadings. The effects of rainflow cycle counting and fatigue crack closure are included. A method for determining the opening stress in a random loading is also proposed. This research takes a fatigue damage factor approach. The damage factor is defined as the ratio of the wide band rainflow fatigue damage to the equivalent narrow band fatigue damage. The mathematical form of the damage factor equations is derived from theoretical derivations using the analytically tractable local range cycle counting method. Simulations of stationary Gaussian random processes are used to empirically derive the values of certain parameters dependent on the spectral shape for the rainflow cycle counting equations. There are five tasks in this research. (1) A simulation program for generating a Gaussian process has been written and is used to generate random loading histories for this study. (2) A previously proposed rainflow damage factor has been verified and refined with these simulations, without considering crack closure. (3) Using a sinusoidal approximation, the joint probability density functions between peaks, valleys and rises counted by the local range method are derived. (4) The resulting joint probability distributions are used to determine the theoretical damage with crack closure; simulations are again used to calibrate the parameters for rainflow stress cycles. (5) A procedure for finding an equivalent constant fatigue crack opening stress for stationary random loadings is described. An example application of the procedures and equations is given.

      Martinez-Flores, Rene; Haldar, Achintya; Haldar, Achintya; Richard, Ralph; Fleischman, Robert; Contractor, Dunshaw N. (The University of Arizona., 2005)
      Experimental verification of a novel system identification technique that can detect defects at the element level is successfully accomplished. The method can be used for in-service health assessment of real structures without disrupting normal operations. This study conclusively verifies the method.Analytical verification of the proposed algorithm has been successfully completed by the research team at the University of Arizona. Vo and Haldar (2004) experimentally verified the method by conducting tests on fixed-ended and simply supported defect-free and defective beams. The purpose of this research was to validate the method by conducting experiments with more realistic structures. A three-story one-bay steel frame, built to 1/3 scale to fit the experimental facility, was considered. The frame was excited by harmonic or impulsive excitation forces. The transverse acceleration responses were collected using capacitive accelerometers. The angular displacement responses were measured using an autocollimator. The dynamic responses of the frames were collected by a data acquisition system with simultaneous sampling capability. Using only experimentally collected response information and completely ignoring the excitation information, the stiffness of all the structural elements were identified. The method identified the defect-free frame very accurately. Defects, in terms of removing a beam, reducing cross sectional area over a small segment of a beam, and cutting notches in a beam, were introduced. The method correctly identified the defect location in all cases. Additional sensors were placed around the location of the defect in an effort to identify the defect spot more accurately. The proposed method also successfully identified defect with improved accuracy. To increase the implementation potential of the proposed method, the defect-free and defective frames are then identified using limited response information. A two-stage Kalman filter-based approach is used. It is denoted as Generalized Iterative Least Square Extended Kalman Filter with Unknown Input (GILS-EKF-UI) method. A sub-structure approach is used for this purpose. The GILS-EKF-UI method also identified the state of the structure using only limited response information. As expected, in this case the error in the identification goes up as less information is used. However, the error is much smaller than other methods currently available in the literature, even when input excitation was used for the identification purpose. The method is very robust and can identify defects caused by different types of loadings. The method can be used as a nondestructive defect assessment technique for structures.
    • Damage Detection and Characterization in Plate Like Structures

      Kundu, Tribikram; Kumar Yadav, Susheel; Kundu, Tribikram; Banerjee, Sourav; Frantziskonis, George; Lansey, Kevin (The University of Arizona., 2013)
      Large civil infrastructure systems all over the world have become an integral part of our civilization. The inspection and maintenance of these structures for public safety is a difficult task. The assessment of integrity of such huge structures due to local damages is even more difficult to deal with. The conventional inspections are performed manually, generally by visual examination and sometimes by more advanced techniques like ultrasonic, electromagnetic and fiber optic techniques. These inspections involve human interventions, depend on individual inspector's experience, and are time consuming. Such inspection methods may not be very useful for real time health assessment of a structure in service and as a result are not very helpful in preventing any disastrous situation through early warning. Therefore, it is very important to look for a comprehensive strategy of global integrity monitoring infused with information about local damages in the structure. For local damage assessment the current state of the health monitoring technology lacks a generalized and definitive approach to the identification and localization of damage. In past decades several signal processing tools have been used for solving different health monitoring problems but the commutability of the tools between different problems has been restricted. Fundamental reasons for this shortcoming have never been investigated in detail. In this dissertation an investigation has been carried out employing almost all promising feature extraction tools on a representative problem - a plate with rivet holes. The problem considered has radial cracks around rivet holes in a joint panel of a steel truss bridge. Such defects are very difficult to detect. Although well established, Lamb wave based nondestructive evaluation techniques are revisited and new tools are developed to address this issue. Simulation of the scattered ultrasonic wave field is carried out using the finite element method. This ultrasonic wave field is further analyzed to evaluate the integrity of the structure using various feature extraction (FE) techniques. Joint time-frequency-energy representation is obtained from ultrasonic signals recorded at various locations on the plate (joint panel) and used to extract damage sensitive features. Those features were then used to formulate a new Damage Parameter (DP) for better visualization of the crack. Results are shown to demonstrate the comparative effectiveness of these techniques. It is concluded that any particular FE technique cannot detect all possible sizes and orientations of the crack. It is suggested that the statistical occurrence and pattern of the crack must be visualized through a few selective FE techniques in a sequence. Modeling of the wave scattering phenomenon by conventional numerical techniques such as finite element method requires very fine mesh at high frequencies necessitating heavy computational power. Distributed point source method (DPSM) which is a recently developed semi-analytical technique, is applied to model the scattering of ultrasonic wave field on representative problem geometries and the results are used to diagnose structural damages. DPSM is a newly developed robust mesh-free technique for simulating ultrasonic, electrostatic and electromagnetic field problems. In most of the previous studies the DPSM technique has been applied to model two dimensional surface geometries and relatively simple three dimensional scatterer geometries. It has been very difficult to perform the wave scattering analysis for very complex three-dimensional geometries. This technique has been extended to model wave scattering in an arbitrary geometry. The simulation has been carried out with and without the presence of cracks near the rivet holes.

      Kundu, Tribikram; SHELKE, AMIT BALASAHEB; Deymier, Pierre; Frantziskonis, George; Kemeny, John (The University of Arizona., 2011)
      This dissertation deals with analytical and experimental investigations of a number of distinct problems related to defect detection in solid structures. All these problems have applications in structural health monitoring (SHM) and nondestructive evaluation (NDE). With this broad goal in mind the mode selective excitation and detection scheme for guided Lamb waves in isotropic and anisotropic plates has been investigated. Change in the time of flight technique is applied to the detection of inherent variations in material properties. Symmetric and anti-symmetric modes are resolved with orthogonal phase difference and homodyning. Noncontact Electro-Magnetic Acoustic Transducers (EMATs) are developed for generation and detection of Lamb waves. Its interaction with circular defects having dimensions comparable to the wavelength is investigated. Short time Fourier Transform and Hilbert Transform are applied for feature detection and identification of localization of damages. Distributed point source method (DPSM) is applied to model the scattering of acoustical wave field and to study the stress singularity in penny shaped cracks. Both experimental and numerical investigations are performed in the framework of structural health monitoring and non destructive evaluation for gaining insight in damage initiation and progression in materials.
    • Damping studies in flexural vibration

      Uchiyama, Jerome Tomio, 1939- (The University of Arizona., 1963)
    • Dance and Self-Concept: The Effects of Varying Forms of Dance Training on Development of Self-Concept

      Hunt, James E.; Panaligan, Anna Patricia (The University of Arizona., 2013)
      This research looks at dance training and its effects on Self-concept and Self-perception. In is a literature review with proposed research methodology. By analyzing forms of dance training in different dance environments we can determine which methods allow for healthy development of self. This research focuses of the argument regarding dance as a sport and physical activity. Using Symbolic Interaction Theory this research looks at how the specific interactions of the individuals in the differing environments affect their development of self. Since there are many genres of dance, individual interactions in the dance realm can be highly varied which could relate to the development of self. Knowing physical activity does lead to positive self-perception, it is necessary to determine how the different environments can affect the final outcome so that instructors and mentors can develop effective methods of teaching.
    • Dance fantasy for symphony orchestra

      Wise, Loren Eugene, 1925- (The University of Arizona., 1959)