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- Genre: Masters Thesis
- Creators: Arizona State University
- Creators: Chakraborty, Bijeta
- Member of: ASU Electronic Theses and Dissertations
Description
Bully victimization has been associated with blunted cardiovascular responses to stress as well as elevated responses to stress. The difference between these altered physiological responses to stress is largely unknown. This study explored several possible moderators to the relationship between chronic stress and future cardiac output (an indicator of increased stress) in response to future stressors. These moderators include the difference between social and physical stressors and individual levels of loneliness. Participants were administered measures of loneliness and victimization history, and led to anticipate either a "social" (recorded speech) or "non-social" (pain tolerance test ) stressor, neither of which occurred. EKG and impedance cardiography were measured throughout the session. When anticipating both stressors, loneliness and victimization were associated with increased CO. A regression revealed a three-way interaction, with change in cardiac output depending on victimization history, loneliness, and condition in the physical stressor condition. Loneliness magnified the CO output levels of non-bullied individuals when facing a physical stressor. These results suggest that non- bullied participants high in loneliness are more stressed out when facing stressors, particularly stressors that are physically threatening in nature.
ContributorsHaneline, Magen (Author) / Newman, Matt (Thesis advisor) / Salerno, Jessica (Committee member) / Miller, Paul (Committee member) / Arizona State University (Publisher)
Created2013
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, 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
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 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
Description
The capability of cocaine-associated stimuli in eliciting craving in human addicts, even after extended periods of abstinence, is modeled in animals using cue reinstatement of extinguished cocaine-seeking behavior. This study aimed to examine brain activation in response to cocaine cues in this model apart from activation produced by test novelty using a novel cue control. Rats trained to self-administer cocaine paired with either an oscillating light or tone cue underwent daily extinction training and were then tested for reinstatement of extinguished cocaine-seeking behavior elicited by response-contingent presentations of either their assigned cocaine-paired cue or the alternate, novel cue. Additional controls received saline infusions and cue presentations yoked to a cocaine-trained rat. Brains were harvested for Fos immunohistochemistry immediately after the 90-min reinstatement test. Surprisingly, conditioned and novel cues both reinstated responding to a similar degree; however magnitude of reinstatement did vary by cue modality with the greatest reinstatement to the light cues. In most brain regions, Fos expression was enhanced in rats with a history of cocaine training regardless of cue type with the exception of the Cg1 region of the anterior cingulate cortex, which was sensitive to test cue modality. Also Fos expression within the dorsomedial caudate-putamen was correlated with responding in the novel, but not conditioned, cue groups. In subsequent experiments, we observed a similar pattern of reinstatement in rats trained and tested for sucrose-seeking behavior, whereas rats trained and tested with the cues only reinstated to a novel light and tone, but not a familiar cue. The results suggest that novel cues reinstate responding to a similar extent as conditioned cues regardless of whether animals have a history of operant-delivered drug or a natural reinforcer. Furthermore, similar brain circuits as those involved in cocaine-seeking behavior are activated by novel cues, suggesting converging processes exist to drive conditioned and novel reinforcement seeking.
ContributorsBastle, Ryan (Author) / Neisewander, Janet L (Thesis advisor) / Sanabria, Federico (Committee member) / Olive, Michael F (Committee member) / Arizona State University (Publisher)
Created2012
Description
The U.S. Surgeon General has recommended that all Americans engage in regular physical activity throughout the lifespan as a way to maintain and improve health and reduce the risk of developing cardiovascular disease, diabetes, obesity, or other chronic conditions. The recommendation for children is a minimum of 60 minutes of moderate and intense physical activity everyday. As children enter adolescence their level of physical activity often decreases; and active adults were typically active adolescents. More than 50% of adults that begin a physical activity program discontinue the behavior within 9 months. Interventions to increase physical activity have looked at self-esteem and self-efficacy. Locus of control (LOC) is a concept that people either view their own behavior as influencing the events around them (internal) or other events controlling their fate or destiny (external). This study looked at locus of control as a predictor of exercise adherence and future exercise patterns in children ages 6-12 in Mesa, AZ. Locus of control as measured by the Child Nowicki-Strickland Internal External (CNSIE) scale differed by gender and by physical activity group at school at post-intervention. Self-reported physical activity as measured by the Physical Activity Questionnaire for Older Children (PAQ-C) showed differences in physical activity (PA) levels by gender for baseline school PA, by age group for baseline non-school PA, by gender and age group for post-intervention school PA, and by gender only for post-intervention non-school PA. A secondary objective was to assess if the Think Healthy About Nutrition and eXercise (THANX) after school program influenced participants' LOC or PA patterns. This study found that the THANX program had no effect on LOC or PA level at any time point.
ContributorsAguila, Holly J (Author) / Chisum, Jack (Thesis advisor) / Woodruff, Larry (Committee member) / Campbell, Kathy (Committee member) / Arizona State University (Publisher)
Created2012
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 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
Description
The unpleasant bitter taste found in many nutritious vegetables may deter people from consuming a healthy diet. We investigated individual differences in taste perception and whether these differences influence the effectiveness of bitterness masking. To test whether phenylthiocarbamide (PTC) `supertasters' also taste salt and sugar with greater intensity, as suggested by Bartoshuk and colleagues (2004), we infused strips of paper with salt water or sugar water. The bitterness rating of the PTC strip had a significant positive linear relationship with ratings of both the intensity of sweet and salt, but the effect sizes were very low, suggesting that the PTC strip does not give a complete picture of tasting ability. Next we investigated whether various seasonings could mask the bitter taste of vegetables and whether this varied with tasting ability. We found that sugar decreased bitterness and lemon decreased liking for vegetables of varying degrees of bitterness. The results did not differ by ability to taste any of the flavors. Therefore, even though there are remarkable individual differences in taste perception, sugar can be used to improve the initial palatability of vegetables and increase their acceptance and consumption.
ContributorsWilkie, Lynn Melissa (Author) / Phillips, Elizabeth D. (Thesis advisor) / Cohen, Adam (Committee member) / Johnston, Carol (Committee member) / Arizona State University (Publisher)
Created2012
Description
Social scientists from many disciplines have examined trust, including trust between those with different religious affiliations, emotional antecedents of trust, and physiological correlates of trust. However, little is known about how all of these factors intersect to shape trust behaviors. The current study aimed to examine physiological responses while individuals engaged in a trust game with a religious in-group or out-group member. Participants were randomly assigned to one of four conditions in which they were presented with the target’s profile before playing the game. In each of the conditions the target was described as either Catholic or Muslim and as someone who engaged in either costly signaling or anti-costly signaling behavior. In addition to assessing the amount of money invested as a behavioral measure of trust, physiological responses, specifically cardiac interbeat interval (IBI) and respiratory sinus arrhythmia (RSA), were measured. I hypothesized that when playing the trust game with a Catholic target as opposed to a Muslim target, Christian participants would (1) report being more similar to the target, (2) trust the target more, (3) invest more money in the target, (4) have a more positive outlook on the amount invested, and (5) show greater cardiorespiratory down-regulation, reflected by increases in IBI and RSA. Findings revealed that Christian participants reported greater similarity and showed a non-significant trend toward reporting a more positive outlook on (greater confidence in/satisfaction with) their investment decision when playing a Catholic versus Muslim target. Additionally, Christian participants who played an anti-costly signaling Catholic target showed greater cardiorespiratory down-regulation (increases from baseline for IBI, reflecting slower heart rate, and increases in RSA) than Christian participants who played an anti-costly signaling Muslim target. Results from this study echo previous findings suggesting that perceived similarity may facilitate trust. Findings also are consistent with previous research suggesting that religious ingroup or outgroup membership may not be as influential in shaping trust decisions if the trustee is costly signaling; for anti-signaling, however, cardiorespiratory down-regulation to a religious ingroup member may be apparent. These physiological signals may provide interoceptive information about a peer’s trustworthiness.
ContributorsThibault, Stephanie A (Author) / Roberts, Nicole A. (Thesis advisor) / Burleson, Mary (Committee member) / Hall, Deborah (Committee member) / Arizona State University (Publisher)
Created2019
Description
Literature was reviewed about how synchrony occurs in infant-parent dyads, in emotion, and physiologically in couple dyads. Social baseline theory suggests that both conversation and interpersonal touch confer benefits by reducing burden on the participants through coregulatory processes. The current study examined how affectionate touch and positive conversation influenced physiological synchrony, a potential mechanism of physiological coregulation, in couples. Because synchrony is believed to occur within the autonomic nervous system, in the present study, physiological synchrony was measured using cardiac interbeat interval (IBI) as an indicator of autonomic nervous system activation. Couples were assigned to one of four conditions: interpersonal touch with positive conversation, interpersonal touch without conversation, positive conversation with no interpersonal touch, and neither interpersonal touch nor conversation. We hypothesized that 1) IBI synchrony between spouses within the real data would be significantly higher than within a phase-shuffled version of the data; and 2) synchrony would be strongest in the touch-talk condition, followed by the touch-no talk condition, followed by the talk-no touch- condition, and finally by the no touch-no talk condition. We also investigated whether there was a tendency for husbands or wives to serve as leader or follower in the four conditions. Using windowed lagged cross-correlations, we found that synchrony within the real data was stronger than synchrony within the shuffled data, suggesting that it reflects an ongoing interpersonal process. Next, we found that there was significantly greater synchrony in the touch-talk than in the touch-no talk condition, marginally greater synchrony in the touch-no talk condition than in the no touch-talk condition, and significantly greater synchrony in the no touch-talk than in the no touch-no talk conditions, suggesting that talk, rather than touch, was driving these synchrony levels. We also found that the only condition with a significant level of leading-following pattern was the no touch-talk condition. More husbands than wives led the covariation in IBI when couples were conversing but not touching. When touch was included this effect did not occur. Future research should include potential moderators such as marital satisfaction and investigate whether seeing one’s partner influences synchrony.
ContributorsMcAfee, Ashley Nicole (Author) / Burleson, Mary (Thesis advisor) / Duran, Nicholas (Committee member) / Roberts, Nicole (Committee member) / Arizona State University (Publisher)
Created2018
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 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%.
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