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Description
Ethnic identity has consistently been associated with Latino youths' psychosocial well-being; however, an area that has received much less attention is how parents' characteristics inform their ethnic socialization efforts and, in turn, youths' ethnic identity. In addition, we know little about how this process unfolds in specific at-risk samples of

Ethnic identity has consistently been associated with Latino youths' psychosocial well-being; however, an area that has received much less attention is how parents' characteristics inform their ethnic socialization efforts and, in turn, youths' ethnic identity. In addition, we know little about how this process unfolds in specific at-risk samples of youth, such as adolescent mothers. Thus, the current prospective study examined how mothers' cultural characteristics informed adolescents' and mothers' reports of ethnic socialization, and how this, in turn, informed adolescents' ethnic identity exploration and resolution among a sample of 193 adolescent mothers and their mothers. In addition, the current study tested whether mothers' ethnic identity affirmation was directly related to adolescents' ethnic identity affirmation over time. Results indicated that mothers' familism was associated with increases in mothers' reports of maternal ethnic socialization, and, in turn, with increases in ethnic identity exploration for foreign-born adolescents, and decreases in ethnic identity exploration for U.S.-born adolescents. In addition, adolescents' reports of familial ethnic socialization were associated with increases in their ethnic identity exploration and resolution. Finally, mothers' ethnic identity affirmation was associated with increases in adolescents' ethnic identity affirmation. Findings are discussed with special attention to the importance of mothers' cultural values in how they socialize their adolescents, and this impact on adolescents' ethnic identity, as well as the implications this study has for interventions focused on bolstering positive outcomes for adolescent mothers.
ContributorsDerlan, Chelsea L (Author) / Umaña-Taylor, Adriana J. (Thesis advisor) / Knight, George P. (Committee member) / Updegraff, Kimberly A. (Committee member) / Arizona State University (Publisher)
Created2012
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Description
Efficiency of components is an ever increasing area of importance to portable applications, where a finite battery means finite operating time. Higher efficiency devices need to be designed that don't compromise on the performance that the consumer has come to expect. Class D amplifiers deliver on the goal of increased

Efficiency of components is an ever increasing area of importance to portable applications, where a finite battery means finite operating time. Higher efficiency devices need to be designed that don't compromise on the performance that the consumer has come to expect. Class D amplifiers deliver on the goal of increased efficiency, but at the cost of distortion. Class AB amplifiers have low efficiency, but high linearity. By modulating the supply voltage of a Class AB amplifier to make a Class H amplifier, the efficiency can increase while still maintaining the Class AB level of linearity. A 92dB Power Supply Rejection Ratio (PSRR) Class AB amplifier and a Class H amplifier were designed in a 0.24um process for portable audio applications. Using a multiphase buck converter increased the efficiency of the Class H amplifier while still maintaining a fast response time to respond to audio frequencies. The Class H amplifier had an efficiency above the Class AB amplifier by 5-7% from 5-30mW of output power without affecting the total harmonic distortion (THD) at the design specifications. The Class H amplifier design met all design specifications and showed performance comparable to the designed Class AB amplifier across 1kHz-20kHz and 0.01mW-30mW. The Class H design was able to output 30mW into 16Ohms without any increase in THD. This design shows that Class H amplifiers merit more research into their potential for increasing efficiency of audio amplifiers and that even simple designs can give significant increases in efficiency without compromising linearity.
ContributorsPeterson, Cory (Author) / Bakkaloglu, Bertan (Thesis advisor) / Barnaby, Hugh (Committee member) / Kiaei, Sayfe (Committee member) / Arizona State University (Publisher)
Created2013
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Description
Mexican-origin adolescent females have the highest birthrate of all other ethnic groups in the U.S. Further, teen mothers are at significant risk for poor outcomes, including low educational attainment. Therefore, examining predictors of Mexican-origin teen mothers' educational attainment was the main goal of the current study. Future-oriented beliefs such as

Mexican-origin adolescent females have the highest birthrate of all other ethnic groups in the U.S. Further, teen mothers are at significant risk for poor outcomes, including low educational attainment. Therefore, examining predictors of Mexican-origin teen mothers' educational attainment was the main goal of the current study. Future-oriented beliefs such as educational aspirations and expectations are suggested to have positive implications for adolescents' educational attainment in general. Therefore, guided by bioecological, social capital, status attainment, social learning, and collective socialization of neighborhood theories, the current study examined neighborhood, maternal, and cultural predictors of 190 Mexican-origin parenting adolescents' educational aspirations, expectations, and attainment. With respect to maternal predictors, the study examined mother figures' (i.e., grandmothers') educational attainment, and aspirations and expectations for the adolescent as predictors of adolescents' educational attainment. Using a multi-informant, longitudinal analytic model, results suggest that adolescents' educational expectations, rather than aspirations, significantly predicted adolescents' attainment one year later. Additionally, grandmothers' educational attainment was indirectly associated with adolescents' educational attainment via the educational expectations of both the grandmother and the adolescent. Further, the neighborhood context indirectly informed adolescents' educational attainment via both grandmothers and adolescents' educational expectations. Finally, adolescents' ethnic identity affirmation was significantly associated with adolescents' educational attainment two years later. Implications regarding the importance of educational expectations and ethnic identity affirmation for at-risk parenting adolescents' educational attainment will be discussed.
ContributorsHarvey-Mendoza, Elizabeth C (Author) / Umaña-Taylor, Adriana J. (Thesis advisor) / Updegraff, Kimberly A. (Committee member) / White, Rebecca (Committee member) / Arizona State University (Publisher)
Created2014
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Description
Low-income Mexican American women face significant risk for poor health during the postpartum period. Chronic stressors are theorized to negatively impact mental and physical health outcomes. However, physiological factors associated with increased self-regulatory capacity, such as resting heart rate variability, may buffer the impact of stress. In a sample of

Low-income Mexican American women face significant risk for poor health during the postpartum period. Chronic stressors are theorized to negatively impact mental and physical health outcomes. However, physiological factors associated with increased self-regulatory capacity, such as resting heart rate variability, may buffer the impact of stress. In a sample of 322 low-income Mexican American women (mother age 18-42; 84% Spanish-speaking; modal family income $10,000-$15,000), the interactive influence of resting heart rate variability and three chronic prenatal stressors (daily hassles, negative life events, economic stress) on maternal cortisol output, depressive symptoms, and self-rated health at 12 weeks postpartum was assessed. The hypothesized interactive effects between resting heart rate variability and the chronic prenatal stressors on the health outcomes were not supported by the data. However, results showed that a higher number of prenatal daily hassles was associated with increased postpartum depressive symptoms, and a higher number of prenatal negative life events was associated with lower postpartum cortisol output. These results suggest that elevated chronic stress during the prenatal period may increase risk for poor health during the postpartum period.
ContributorsJewell, Shannon Linda (Author) / Luecken, Linda J. (Thesis advisor) / Lemery-Chalfant, Kathryn (Committee member) / Perez, Marisol (Committee member) / Arizona State University (Publisher)
Created2015
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Description
Class D Amplifiers are widely used in portable systems such as mobile phones to achieve high efficiency. The demands of portable electronics for low power consumption to extend battery life and reduce heat dissipation mandate efficient, high-performance audio amplifiers. The high efficiency of Class D amplifiers (CDAs) makes them particularly

Class D Amplifiers are widely used in portable systems such as mobile phones to achieve high efficiency. The demands of portable electronics for low power consumption to extend battery life and reduce heat dissipation mandate efficient, high-performance audio amplifiers. The high efficiency of Class D amplifiers (CDAs) makes them particularly attractive for portable applications. The Digital class D amplifier is an interesting solution to increase the efficiency of embedded systems. However, this solution is not good enough in terms of PWM stage linearity and power supply rejection. An efficient control is needed to correct the error sources in order to get a high fidelity sound quality in the whole audio range of frequencies. A fundamental analysis on various error sources due to non idealities in the power stage have been discussed here with key focus on Power supply perturbations driving the Power stage of a Class D Audio Amplifier. Two types of closed loop Digital Class D architecture for PSRR improvement have been proposed and modeled. Double sided uniform sampling modulation has been used. One of the architecture uses feedback around the power stage and the second architecture uses feedback into digital domain. Simulation & experimental results confirm that the closed loop PSRR & PS-IMD improve by around 30-40 dB and 25 dB respectively.
ContributorsChakraborty, Bijeta (Author) / Bakkaloglu, Bertan (Thesis advisor) / Garrity, Douglas (Committee member) / Ozev, Sule (Committee member) / Arizona State University (Publisher)
Created2012
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Description
In this thesis, a digital input class D audio amplifier system which has the ability

to reject the power supply noise and nonlinearly of the output stage is presented. The main digital class D feed-forward path is using the fully-digital sigma-delta PWM open loop topology. Feedback loop is used to suppress

In this thesis, a digital input class D audio amplifier system which has the ability

to reject the power supply noise and nonlinearly of the output stage is presented. The main digital class D feed-forward path is using the fully-digital sigma-delta PWM open loop topology. Feedback loop is used to suppress the power supply noise and harmonic distortions. The design is using global foundry 0.18um technology.

Based on simulation, the power supply rejection at 200Hz is about -49dB with

81dB dynamic range and -70dB THD+N. The full scale output power can reach as high as 27mW and still keep minimum -68dB THD+N. The system efficiency at full scale is about 82%.
ContributorsBai, Jing (Author) / Bakkaloglu, Bertan (Thesis advisor) / Arizona State University (Publisher)
Created2015