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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

THE SELF-REPORTED AND BEHAVIORAL EFFECTS OF PROPYLENE GLYCOL AND VEGETABLE GLYCERIN IN ELECTRONIC CIGARETTE LIQUIDS

Harvanko, Arit M. 01 January 2018 (has links)
Little is known about how electronic cigarette (EC) users manipulate device parameters, what factors drive their use, and how non-nicotine ingredients influence the stimulus effects of EC aerosols. The ingredients propylene glycol (PG) or vegetable glycerin (VG) serve as the base for virtually all electronic cigarette liquids, and information on how they affect the using experience would provide important groundwork for the study of other ingredients. In this dissertation, results from a survey and laboratory study focused on the stimulus effects of ECs, and the influence of PG and VG, will be discussed. A total of 522 regular EC users completed a survey comprised of an electronic cigarette dependence questionnaire, questions on tobacco and electronic cigarette use, and device and liquid preferences. This was followed by a laboratory study with sixteen electronic cigarette users completing five test days (one practice and four assessment days). In the laboratory study, following one hour of nicotine deprivation, two sampling puffs from liquid formulations containing 100/0, 75/25, 50/50, 25/75, and 0/100% PG/VG concentrations were administered in random order during five assessments, each separated by 20 min. Primary outcome measures were self-reported stimulus characteristics and breakpoint on a multiple-choice procedure. Survey results indicated that ability to change device voltage, and level of resistance, was significantly associated with level of nicotine dependence, as was amount of liquid consumed, nicotine concentration, and milligrams of nicotine used per week. Participants also rated 'good taste' as the most important consideration when purchasing and using liquids, and PG was associated with undesirable effects and VG with desirable effects. Laboratory results indicated that greater VG content was associated with greater reports of visibility of the exhalant (i.e. “cloud”). Liquids with mixtures of PG or VG were associated with conventional cigarette smoking sensations and greater reductions of systolic blood pressure compared to formulations with only PG or VG. There was no significant effect of liquid formulation on the multiple-choice procedure, but puffs were rarely chosen over even the smallest monetary option ($0.05), suggesting minimal reinforcing efficacy. In conclusion, survey data indicate that a wide range device parameter settings and liquid ingredients are preferred by daily e-cigarette users, and that individuals with greater nicotine dependence favor voltage control devices, and lower resistance heating elements. Survey data also indicated that taste is a key factor for EC liquid selection, and relative concentrations of propylene glycol and vegetable glycerin may have a significant impact on the reinforcing effects of liquids. In contrast, laboratory data suggests that PG or VG do not significantly impact the abuse liability of EC liquids, though reinforcing effects of these ingredients was unclear in the laboratory study.
52

Mitigating the Effects of Withdrawal Behavior on Organizations

Alexander, James Fitzgerald 01 January 2016 (has links)
Withdrawal behaviors such as absenteeism, tardiness, turnover intention, and employee disengagement adversely affect organizations, costing billions of dollars annually. However, there is limited research on the best practices for minimizing the effects of employee withdrawal. The purpose of this qualitative case study was to explore best practices leaders need to mitigate the effects of withdrawal behaviors on organizations. The social learning theory (SLT) served as the conceptual framework for this study. Ten participants were interviewed, including 4 healthcare leaders and 6 health service workers from a correctional facility nursing department in the Southeastern United States. Scholars have indicated that correctional healthcare personnel exhibit high levels of employee withdrawal including absenteeism and turnover. Data from semistructured interviews were analyzed and compared with training and disciplinary policy statements for methodological triangulation. Several themes emerged including a need for leadership engagement, staff accountability, and an organizational culture that discourages withdrawal behaviors. The findings may contribute to the body of knowledge regarding best practices that leaders can utilize to diminish adverse effects withdrawal behaviors have on organizations. Information derived from this study might contribute to social change by decreasing the expense of employee withdrawal behaviors on citizens and reallocate taxpayer resources to appropriations necessary for public inpatient mental health treatment facilities.
53

Use of Brief Experimental Assessment for Selecting Interventions to Increase Positive Social Interaction

Cox, Michelle S. 01 May 2009 (has links)
Different reasons for social withdrawal include a performance deficit, a social skill deficit, lack of peer support, and avoidance of anxiety or aversive interactions. Each of these reasons for social withdrawal may require a different intervention. This study investigated the utility of brief experimental analysis for identifying the most functional intervention to increase positive peer interactions for three socially withdrawn students. Using a multiple baseline and multi-element single subject design, three treatments were administered to compare differences in peer interactions during recess. Interventions were contingent reward, a social skills training with peer mediation, and a brief cognitive-behavioral strategy. Although students responded differently to the three interventions, the social skills training with peer mediation intervention showed the greatest gains for all students during the brief assessment and when implemented over time.
54

Dyadic Approach and Withdrawal Sequences of Preschool Children when Interacting with an Adult Male

Crane, Paul M. 01 May 1978 (has links)
Thirty-eight preschool children (20 male and 18 females) w ere filmed in a seated dyadic interaction with an adult experimenter. Frame- by-frame film analysis was done for head and arms of subjects and head, arms, and legs of experimenter for expe rimenter and subjects approach and withdrawal movements. Chi- square analysis were pe rformed for the data both between and within zones with the following cells: approach-approach (A-A), experimenter and subject approach each other; approach-withdrawal (A-W), experimenter approaches and subject withdraws; withdrawal-approach (W -A), experimenter withdraws and subject approaches; withdrawal-withdrawal (W - W), both subject and experimenter withdraw. The most frequent and significant movements for each zone and body part were A-Wand W -A. It was found that in the 3 foot zone the A-W cells (of the 2 X 2 contingency table) were the most frequent dyadic movements. For the 2 and 1 foot zones the W -A cells were the most frequent. For all three one-foot zones the W-W and A-A were respectively the least frequent dyadic interactional patterns. The intimate zone of personal space was found to be larger than the 18 inches previously identified for adults; it was found to be over 24 inches. Modifications for personal space and equilibrium theories to accommodate present findings are advanced.
55

Self-Control Depletion and Nicotine Deprivation as Precipitants of Smoking Cessation Failure: A Human Laboratory Model

Heckman, Bryan 27 May 2014 (has links)
The need to understand the reinforcing properties of smoking and potential precipitants of relapse is exemplified by evidence that relapse rates exceed 95%. The Self-Control Strength model, which proposes that self-control is dependent upon limited resources and susceptible to fatigue, may offer insight into the relapse process. Indeed, there is empirical support that engaging in a task that requires self-control, relative to a comparable control, results in performance decrements on subsequent self-control tasks. The primary goal of the current study was to test whether self-control depletion (SCD) may serve as a novel antecedent for cessation failure, using a validated laboratory analogue of smoking lapse and relapse. We also aimed to compare SCD effects to those of a well-established relapse precipitant (i.e., nicotine deprivation), and test craving and behavioral economic indices as mechanisms for increased cessation failure. We used a 2 X 2 (12-hour deprivation vs. no deprivation; SCD vs. no SCD), crossed-factorial, between-subjects design (N=128 smokers). Replicating prior research, nicotine deprivation significantly increased craving, cigarette demand, delay discounting, and lapse behavior. Furthermore, craving was the only mediator of deprivation effects on lapse behavior. Finally, the primary hypothesis of the study was supported, as SCD increased lapse behavior (p = .04). Although no main effects were found for SCD on putative mediators (i.e., craving, demand, discounting), SCD was found to increase craving among nicotine deprived smokers (p = .04), which mediated cessation failure. SCD appears to play in important role in smoking behavior and may be a viable candidate for intervention.
56

Influencing Factors on Methadone Pharmacology: Impact on Satisfaction with Methadone Maintenance Treatment

Elkader, Alexander 24 September 2009 (has links)
The methadone maintenance treatment population suffers from high rates of comorbid psychiatric and substance use disorders. Despite a more than 40-year treatment history, not all patients are satisfied with methadone treatment and more than half of the patients complain of significant inter-dose withdrawal at least some of the time. The objectives of this research were to investigate the pharmacological response to methadone under the influence of comorbid major depressive disorder and smoking; and to identify factors other than physical withdrawal symptoms that can differentiate patients based on their complaints of dissatisfaction with treatment. In Study 1, seven depressed methadone maintenance patients experienced more opioid withdrawal symptomatology over a 24-hour methadone-dosing interval than 10 nondepressed methadone patients. Depression severity was significantly correlated with trough opioid withdrawal severity. This suggests that depression or depressive symptoms are related to reported opioid withdrawal. In Study 2, many factors other than physical opioid withdrawal symptoms were able to differentiate patients who were satisfied with treatment (holders, n=25), partially satisfied with treatment (partial holders, n=35), and not satisfied with treatment(nonholders, n=30). Results suggested that these patient satisfaction groups cluster differently depending on physical opioid withdrawal, mood, psychological distress, and personality. Nonholders experienced more physical withdrawal symptoms, craving for opioids, and negative drug effects. Holders had less psychological distress and experienced less negative mood states than the other groups. Partial holders had less agreeable personalities compared to patients in the other groups. In Study 3, opioid and nicotine withdrawal symptoms and effects were measured in 40 methadone-maintained patients who were current smokers during trough and peak methadone effects, both pre and post-nicotine administration. Cigarette smoking enhanced opioid withdrawal suppression during the peak methadone condition, methadone attenuated nicotine withdrawal, and methadone and nicotine shared many of the same main effects, suggesting that smoking and methadone effects may be inseparable dimensions. In summary, the results of these studies suggest that in addition to physical symptoms, mood related factors are important to opioid withdrawal perception and that the mood factors and drug interactions can impact on a patient’s perception of satisfaction with methadone treatment.
57

Influencing Factors on Methadone Pharmacology: Impact on Satisfaction with Methadone Maintenance Treatment

Elkader, Alexander 24 September 2009 (has links)
The methadone maintenance treatment population suffers from high rates of comorbid psychiatric and substance use disorders. Despite a more than 40-year treatment history, not all patients are satisfied with methadone treatment and more than half of the patients complain of significant inter-dose withdrawal at least some of the time. The objectives of this research were to investigate the pharmacological response to methadone under the influence of comorbid major depressive disorder and smoking; and to identify factors other than physical withdrawal symptoms that can differentiate patients based on their complaints of dissatisfaction with treatment. In Study 1, seven depressed methadone maintenance patients experienced more opioid withdrawal symptomatology over a 24-hour methadone-dosing interval than 10 nondepressed methadone patients. Depression severity was significantly correlated with trough opioid withdrawal severity. This suggests that depression or depressive symptoms are related to reported opioid withdrawal. In Study 2, many factors other than physical opioid withdrawal symptoms were able to differentiate patients who were satisfied with treatment (holders, n=25), partially satisfied with treatment (partial holders, n=35), and not satisfied with treatment(nonholders, n=30). Results suggested that these patient satisfaction groups cluster differently depending on physical opioid withdrawal, mood, psychological distress, and personality. Nonholders experienced more physical withdrawal symptoms, craving for opioids, and negative drug effects. Holders had less psychological distress and experienced less negative mood states than the other groups. Partial holders had less agreeable personalities compared to patients in the other groups. In Study 3, opioid and nicotine withdrawal symptoms and effects were measured in 40 methadone-maintained patients who were current smokers during trough and peak methadone effects, both pre and post-nicotine administration. Cigarette smoking enhanced opioid withdrawal suppression during the peak methadone condition, methadone attenuated nicotine withdrawal, and methadone and nicotine shared many of the same main effects, suggesting that smoking and methadone effects may be inseparable dimensions. In summary, the results of these studies suggest that in addition to physical symptoms, mood related factors are important to opioid withdrawal perception and that the mood factors and drug interactions can impact on a patient’s perception of satisfaction with methadone treatment.
58

Pricing and Hedging the Guaranteed Minimum Withdrawal Benefits in Variable Annuities

Liu, Yan January 2010 (has links)
The Guaranteed Minimum Withdrawal Benefits (GMWBs) are optional riders provided by insurance companies in variable annuities. They guarantee the policyholders' ability to get the initial investment back by making periodic withdrawals regardless of the impact of poor market performance. With GMWBs attached, variable annuities become more attractive. This type of guarantee can be challenging to price and hedge. We employ two approaches to price GMWBs. Under the constant static withdrawal assumption, the first approach is to decompose the GMWB and the variable annuity into an arithmetic average strike Asian call option and an annuity certain. The second approach is to treat the GMWB alone as a put option whose maturity and payoff are random. Hedging helps insurers specify and manage the risks of writing GMWBs, as well as find their fair prices. We propose semi-static hedging strategies that offer several advantages over dynamic hedging. The idea is to construct a portfolio of European options that replicate the conditional expected GMWB liability in a short time period, and update the portfolio after the options expire. This strategy requires fewer portfolio adjustments, and outperforms the dynamic strategy when there are random jumps in the underlying price. We also extend the semi-static hedging strategies to the Heston stochastic volatility model.
59

Attenuated Effects of Opiates in Adolescent vs. Adult Male Rats: Reinforcement, Relapse, and Withdrawal

Doherty, James M 15 July 2011 (has links)
Adolescence in humans is a vulnerable period for illicit drug use, and teenage onset of drug use is associated with long-term addiction. Adolescent sensitivity to drug reinforcement, relapse, and withdrawal has not been explored thoroughly in animal models, especially considering opiate drugs such as morphine and heroin. The present series of studies profiles adolescent sensitivity to opiates using adolescent and adult male rats to test for age differences in opiate self-administration, reinstatement, withdrawal signs, locomotor sensitization, and even brain activation during drug-seeking. To test for acute sensitivity to the reinforcing effects of morphine or heroin, we compared patterns of self-administration by adolescent vs. adult male rats on various schedules of reinforcement, drug doses, and daily access conditions. Using fixed ratio schedules and short daily access, adolescents self-administered less morphine than adults, an effect commonly interpreted as higher drug sensitivity. In contrast, escalation of morphine intake under long access conditions was similar across ages, as was heroin intake using fixed or progressive ratio schedules of reinforcement. To test for enduring effects of opiates, we compared opiate-seeking in the absence of the drug in tests of extinction responding and cue-induced reinstatement. Regardless of the acute effects of morphine or heroin, all adolescent treatment groups showed attenuated opiate-seeking compared to adults. Next we considered behavioral correlates of reinforcement, drug withdrawal and locomotor sensitization, during and after escalating doses of experimenter-administered heroin. Consistent with attenuated opiate-seeking, adolescents exhibited attenuated somatic and locomotor signs of withdrawal compared with adults, although locomotor sensitization was similar across ages. Finally, the medial prefrontal cortex (mPFC) is a brain region heavily implicated in drug reinforcement, so we used tissue levels of Fos-like immunoreactivity to compare activation of this region by heroin-seeking. Indeed mPFC activation was absent in rats that self-administered heroin as adolescents, but robust in adults. Together these behavioral and neuroanatomical results surprisingly suggest that adolescent male rats are less sensitive than adults to some acute and enduring effects of opiates, and may predict better response profiles among younger human addicts. Through future studies, adolescent rats may provide a new model to help identify treatments for drug abuse.
60

Pricing and Hedging the Guaranteed Minimum Withdrawal Benefits in Variable Annuities

Liu, Yan January 2010 (has links)
The Guaranteed Minimum Withdrawal Benefits (GMWBs) are optional riders provided by insurance companies in variable annuities. They guarantee the policyholders' ability to get the initial investment back by making periodic withdrawals regardless of the impact of poor market performance. With GMWBs attached, variable annuities become more attractive. This type of guarantee can be challenging to price and hedge. We employ two approaches to price GMWBs. Under the constant static withdrawal assumption, the first approach is to decompose the GMWB and the variable annuity into an arithmetic average strike Asian call option and an annuity certain. The second approach is to treat the GMWB alone as a put option whose maturity and payoff are random. Hedging helps insurers specify and manage the risks of writing GMWBs, as well as find their fair prices. We propose semi-static hedging strategies that offer several advantages over dynamic hedging. The idea is to construct a portfolio of European options that replicate the conditional expected GMWB liability in a short time period, and update the portfolio after the options expire. This strategy requires fewer portfolio adjustments, and outperforms the dynamic strategy when there are random jumps in the underlying price. We also extend the semi-static hedging strategies to the Heston stochastic volatility model.

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