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- Creators: Arizona State University
Description
Background: Smartphone diet tracking applications (apps) are increasing in popularity but may not adequately address the important concerns of proper intake and of diet quality. Two novel weight loss apps were designed based on the popular dietary frameworks: MyPlate and FoodLists. MyPlate, the dietary guidelines put forth by the U.S. government, encourages a balanced diet from five primary food groups, but does not specify intake limits. The Food Lists set upper intake limits on all food groups except vegetables, and these guidelines extend to include fats, sweets, and alcohol.
Objective: The purpose of this randomized controlled trial was to determine whether adherence to a weight loss app providing intake limits and more food group detail (the Food Lists app) facilitated more weight loss and better diet quality than adherence to a weight loss app based on the MyPlate platform. An additional objective was to examine whether higher app adherence would lead to greater weight loss.
Design: Thirty seven adults from a campus population were recruited, randomized, and instructed to follow either the Food Lists app (N=20) or the MyPlate app (N=17) for eight weeks. Subjects received one 15 minute session of diet and app training at baseline, and their use of the app was tracked daily. Body mass was measured at baseline and post-test.
Participants/setting: Healthy adults from a university campus population in downtown Phoenix, Arizona with BMI 24 to 40, medically stable, and who owned a smartphone.
Main outcome measures: Outcome measures included weight change, days of adherence, and diet quality change. Secondary measures included BMI, fat %, and waist circumference.
Statistical analysis: Descriptive statistics (means and standard errors); Repeated measures ANOVAs analyzing weight, diet quality, and BMI; Pearson and Spearman correlations analyzing adherence and weight loss.
Results: Repeated measures ANOVAs and correlations revealed no significant mean differences in primary outcome variables of weight loss, adherence, or diet quality (P=0.140; P=0.790; P=0.278). However, there was a significant mean reduction of BMI favoring the group using the Food Lists app (P=0.041).
Conclusion: The findings strengthen the idea that intake limits and food group detail may be associated with weight loss. Further investigation is warranted to determine whether longer use of the Food Lists app can produce more significant dieting successes and encourage healthier behavioral outcomes.
Objective: The purpose of this randomized controlled trial was to determine whether adherence to a weight loss app providing intake limits and more food group detail (the Food Lists app) facilitated more weight loss and better diet quality than adherence to a weight loss app based on the MyPlate platform. An additional objective was to examine whether higher app adherence would lead to greater weight loss.
Design: Thirty seven adults from a campus population were recruited, randomized, and instructed to follow either the Food Lists app (N=20) or the MyPlate app (N=17) for eight weeks. Subjects received one 15 minute session of diet and app training at baseline, and their use of the app was tracked daily. Body mass was measured at baseline and post-test.
Participants/setting: Healthy adults from a university campus population in downtown Phoenix, Arizona with BMI 24 to 40, medically stable, and who owned a smartphone.
Main outcome measures: Outcome measures included weight change, days of adherence, and diet quality change. Secondary measures included BMI, fat %, and waist circumference.
Statistical analysis: Descriptive statistics (means and standard errors); Repeated measures ANOVAs analyzing weight, diet quality, and BMI; Pearson and Spearman correlations analyzing adherence and weight loss.
Results: Repeated measures ANOVAs and correlations revealed no significant mean differences in primary outcome variables of weight loss, adherence, or diet quality (P=0.140; P=0.790; P=0.278). However, there was a significant mean reduction of BMI favoring the group using the Food Lists app (P=0.041).
Conclusion: The findings strengthen the idea that intake limits and food group detail may be associated with weight loss. Further investigation is warranted to determine whether longer use of the Food Lists app can produce more significant dieting successes and encourage healthier behavioral outcomes.
ContributorsScholtz, Cameron (Author) / Johnston, Carol (Thesis advisor) / Mayol-Kreiser, Sandra (Committee member) / Hekler, Eric (Committee member) / Arizona State University (Publisher)
Created2016
Description
Drinking vinegar is a popularly discussed remedy for relieving heartburn symptom, as can be read on many websites; however, there has been no scientific research or theory to support its efficacy. This randomized, placebo-controlled, double-blind, cross-over research study tested the efficacy of the organic apple cider vinegar, with mother, on alleviation of the heartburn symptom related to Gastro-esophageal reflux disease (GERD). A minimum of one week separated the four trial arms: chili (placebo), antacid after chili meal (positive control), vinegar added to chili, and diluted vinegar after chili meal. Twenty grams of vinegar were used in both vinegar treatments, and 10 grams of liquid antacid were used in the antacid trial. A five-point Likert scale and a 10-cm visual analogue scale (VAS) were used to assess heartburn severity during a 120 minutes testing time. Seven of 15 recruited subjects' data was usable for statistical analysis (age: 39.6 ± 12.2 y, body mass index (BMI): 29.4 ± 4.2 kg/m2, waist circumference: 36.4 ± 4.1 inch). There was no statistically significant difference among the mean and incremental area-under-the-curve (iAUC) heartburn scores among different trials (Likert scale questionnaire p= .259, VAS questionnaire p= .659, iAUC Likert scale p= .184, iAUC VAS p= .326). Seven participants were further divided into antacid responder (n=4) and antacid non-responder groups (n=3). Likert scale mean heartburn score and iAUC data in antacid responder group had significant finding (p= .034 and p= .017 respectively). The significance lay between antacid and 'vinegar added to chili' trials. Effect size was also used to interpret data due to the small sample size: Likert scale: mean heartburn score= .444, iAUC= .425; VAS mean heartburn score= .232, iAUC .611. Effect size for antacid responder group was Likert scale: mean heartburn score= .967, iAUC= .936. Future research is needed to examine whether ingesting organic vinegar benefits alleviation of heartburn symptom related to GERD for people who do not respond well to antacid.
ContributorsYeh, Zoe (Author) / Johnston, Carol (Thesis advisor) / Mayol-Kreiser, Sandra (Committee member) / Lespron, Christy (Committee member) / Arizona State University (Publisher)
Created2016
Description
Energy consumption in buildings, accounting for 41% of 2010 primary energy consumption in the United States (US), is particularly vulnerable to climate change due to the direct relationship between space heating/cooling and temperature. Past studies have assessed the impact of climate change on long-term mean and/or peak energy demands. However, these studies usually neglected spatial variations in the “balance point” temperature, population distribution effects, air-conditioner (AC) saturation, and the extremes at smaller spatiotemporal scales, making the implications of local-scale vulnerability incomplete. Here I develop empirical relationships between building energy consumption and temperature to explore the impact of climate change on long-term mean and extremes of energy demand, and test the sensitivity of these impacts to various factors. I find increases in summertime electricity demand exceeding 50% and decreases in wintertime non-electric energy demand of more than 40% in some states by the end of the century. The occurrence of the most extreme (appearing once-per-56-years) electricity demand increases more than 2600 fold, while the occurrence of the once per year extreme events increases more than 70 fold by the end of this century. If the changes in population and AC saturation are also accounted for, the impact of climate change on building energy demand will be exacerbated.
Using the individual building energy simulation approach, I also estimate the impact of climate change to different building types at over 900 US locations. Large increases in building energy consumption are found in the summer, especially during the daytime (e.g., >100% increase for warehouses, 5-6 pm). Large variation of impact is also found within climate zones, suggesting a potential bias when estimating climate-zone scale changes with a small number of representative locations.
As a result of climate change, the building energy expenditures increase in some states (as much as $3 billion/year) while in others, costs decline (as much as $1.4 billion/year). Integrated across the contiguous US, these variations result in a net savings of roughly $4.7 billion/year. However, this must be weighed against the cost (exceeding $19 billion) of adding electricity generation capacity in order to maintain the electricity grid’s reliability in summer.
Using the individual building energy simulation approach, I also estimate the impact of climate change to different building types at over 900 US locations. Large increases in building energy consumption are found in the summer, especially during the daytime (e.g., >100% increase for warehouses, 5-6 pm). Large variation of impact is also found within climate zones, suggesting a potential bias when estimating climate-zone scale changes with a small number of representative locations.
As a result of climate change, the building energy expenditures increase in some states (as much as $3 billion/year) while in others, costs decline (as much as $1.4 billion/year). Integrated across the contiguous US, these variations result in a net savings of roughly $4.7 billion/year. However, this must be weighed against the cost (exceeding $19 billion) of adding electricity generation capacity in order to maintain the electricity grid’s reliability in summer.
ContributorsHuang, Jianhua (Author) / Gurney, Kevin Robert (Thesis advisor) / Miller, Clark Anson (Committee member) / Rey, Sergio J (Committee member) / Georgescu, Matei (Committee member) / Arizona State University (Publisher)
Created2016
Description
The energy required in a eukaryotic cell is provided by mitochondria. Mitochondrial electron transport chain (ETC) coupled with oxidative phosphorylation generates ATP. During electron transport, electron leakage from the ETC produces reactive oxygen species (ROS). In healthy cells, there are preventive and defense mechanisms in place to manage ROS. Maintaining a steady balance of ROS is very important because overproduction of ROS can lead to several pathological conditions. There are several strategies to prevent ROS production. Addition of external antioxidants is widely used among them. Discussed in the first part of Chapter 1 is the mitochondrial ETC, ROS production and antioxidant strategies.
The second part of Chapter 1 is concerned with ribosomal protein synthesis in bacteria. Ribosome, the organelle that synthesizes proteins with exceptional fidelity, has a strong bias for α-L-amino acids. It has been demonstrated that reengineering of the peptidyltransferase center (PTC) of the ribosome could enable the incorporation of both α-D-amino acids and β-amino acids into full length protein.
Oxidative stress is a common cause of various neurological disorders such as Alzheimer’s disease and Parkinson’s disease. Antioxidative strategies are used widely for the treatment of these disorders. Although several antioxidants demonstrated positive results in vitro as well as in in vivo models, none of them have been effective in clinical settings. Hence, there is an ongoing search for effective neuroprotective drugs. Described in Chapter 2 is the synthesis and biological evaluation of several methylene blue analogues as potentially effective antioxidants for the treatment of pathologies related to oxidative stress.
In Chapter 3, the synthesis and ribosomal incorporation of several rationally designed dipeptidomimetic analogues are discussed. The dipeptidomimetic analogues are structurally similar to the GFP chromophore and, therefore, highly fluorescent. In addition, the backbone of the dipeptidomimetic analogues resemble the peptide backbone of a dipeptide, due to which they can be incorporated into protein by modified ribosomes selected for the incorporation of dipeptides.
Discussed in Chapter 4 is the synthesis of the pdCpA derivatives of several β-amino acids. The pdCpA derivatives were ligated to tRNA-COH and were used as probes for studying the regio- and stereoselectivity of modified ribosomes.
The second part of Chapter 1 is concerned with ribosomal protein synthesis in bacteria. Ribosome, the organelle that synthesizes proteins with exceptional fidelity, has a strong bias for α-L-amino acids. It has been demonstrated that reengineering of the peptidyltransferase center (PTC) of the ribosome could enable the incorporation of both α-D-amino acids and β-amino acids into full length protein.
Oxidative stress is a common cause of various neurological disorders such as Alzheimer’s disease and Parkinson’s disease. Antioxidative strategies are used widely for the treatment of these disorders. Although several antioxidants demonstrated positive results in vitro as well as in in vivo models, none of them have been effective in clinical settings. Hence, there is an ongoing search for effective neuroprotective drugs. Described in Chapter 2 is the synthesis and biological evaluation of several methylene blue analogues as potentially effective antioxidants for the treatment of pathologies related to oxidative stress.
In Chapter 3, the synthesis and ribosomal incorporation of several rationally designed dipeptidomimetic analogues are discussed. The dipeptidomimetic analogues are structurally similar to the GFP chromophore and, therefore, highly fluorescent. In addition, the backbone of the dipeptidomimetic analogues resemble the peptide backbone of a dipeptide, due to which they can be incorporated into protein by modified ribosomes selected for the incorporation of dipeptides.
Discussed in Chapter 4 is the synthesis of the pdCpA derivatives of several β-amino acids. The pdCpA derivatives were ligated to tRNA-COH and were used as probes for studying the regio- and stereoselectivity of modified ribosomes.
ContributorsRoy Chowdhury, Sandipan (Author) / Hecht, Sidney (Thesis advisor) / Gould, Ian (Committee member) / Gust, John Devens (Committee member) / Arizona State University (Publisher)
Created2016
Description
Characterization and modeling of deformation and failure in metallic materials under extreme conditions, such as the high loads and strain rates found under shock loading due to explosive detonation and high velocity-impacts, are extremely important for a wide variety of military and industrial applications. When a shock wave causes stress in a material that exceeds the elastic limit, plasticity and eventually spallation occur in the material. The process of spall fracture, which in ductile materials stems from strain localization, void nucleation, growth and coalescence, can be caused by microstructural heterogeneity. The analysis of void nucleation performed from a microstructurally explicit simulation of a spall damage evolution in a multicrystalline copper indicated triple junctions as the preferred sites for incipient damage nucleation revealing 75% of them with at least two grain boundaries with misorientation angle between 20-55°. The analysis suggested the nature of the boundaries connecting at a triple junction is an indicator of their tendency to localize spall damage. The results also showed that damage propagated preferentially into one of the high angle boundaries after voids nucleate at triple junctions. Recently the Rayleigh-Taylor Instability (RTI) and the Richtmyer-Meshkov Instability (RMI) have been used to deduce dynamic material strength at very high pressures and strain rates. The RMI is used in this work since it allows using precise diagnostics such as Transient Imaging Displacement Interferometry (TIDI) due to its slower linear growth rate. The Preston-Tonks-Wallace (PTW) model is used to study the effects of dynamic strength on the behavior of samples with a fed-thru RMI, induced via direct laser drive on a perturbed surface, on stability of the shock front and the dynamic evolution of the amplitudes and velocities of the perturbation imprinted on the back (flat) surface by the perturbed shock front. Simulation results clearly showed that the amplitude of the hydrodynamic instability increases with a decrease in strength and vice versa and that the amplitude of the perturbed shock front produced by the fed-thru RMI is also affected by strength in the same way, which provides an alternative to amplitude measurements to study strength effects under dynamic conditions. Simulation results also indicate the presence of second harmonics in the surface perturbation after a certain time, which were also affected by the material strength.
ContributorsGautam, Sudrishti (Author) / Peralta, Pedro (Thesis advisor) / Oswald, Jay (Committee member) / Solanki, Kiran (Committee member) / Arizona State University (Publisher)
Created2016
Description
Broadband dielectric spectroscopy is a powerful technique for understanding the dynamics in supercooled liquids. It generates information about the timescale of the orientational motions of molecular dipoles within the liquid. However, dynamics of liquids measured in the non-linear response regime has recently become an area of significant interest, because additional information can be obtained compared with linear response measurements.
The first part of this thesis describes nonlinear dielectric relaxation experiments performed on various molecular glass forming-liquids, with an emphasis on the response at high frequencies (excess wing). A significant nonlinear dielectric effect (NDE) was found to persist in these modes, and the magnitude of this NDE traces the temperature dependence of the activation energy. A time resolved measurement technique monitoring the dielectric loss revealed that for the steady state NDE to develop it would take a very large number of high amplitude alternating current (ac) field cycles. High frequency modes were found to be ‘slaved’ to the average structural relaxation time, contrary to the standard picture of heterogeneity. Nonlinear measurements were also performed on the Johari-Goldstein β-relaxation process. High ac fields were found to modify the amplitudes of these secondary modes. The nonlinear features of this secondary process are reminiscent of those found for the excess wing regime, suggesting that these two contributions to dynamics have common origins.
The second part of this thesis describes the nonlinear effects observed from the application of high direct current (dc) bias fields superposed with a small amplitude sinusoidal ac field. For several molecular glass formers, the application of a dc field was found to slow down the system via reduction in configurational entropy (Adam-Gibbs relation). Time resolved measurements indicated that the rise of the non-linear effect is slower than its decay, as observed in the electro-optical Kerr effect. A model was discussed which quantitatively captures the observed magnitudes and time dependencies of the NDE. Asymmetry in these rise and decay times was demonstrated as a consequence of the quadratic field dependence of the entropy change. It was demonstrated that the high bias field modifies the polarization response to the field, even including the zero field limit.
The first part of this thesis describes nonlinear dielectric relaxation experiments performed on various molecular glass forming-liquids, with an emphasis on the response at high frequencies (excess wing). A significant nonlinear dielectric effect (NDE) was found to persist in these modes, and the magnitude of this NDE traces the temperature dependence of the activation energy. A time resolved measurement technique monitoring the dielectric loss revealed that for the steady state NDE to develop it would take a very large number of high amplitude alternating current (ac) field cycles. High frequency modes were found to be ‘slaved’ to the average structural relaxation time, contrary to the standard picture of heterogeneity. Nonlinear measurements were also performed on the Johari-Goldstein β-relaxation process. High ac fields were found to modify the amplitudes of these secondary modes. The nonlinear features of this secondary process are reminiscent of those found for the excess wing regime, suggesting that these two contributions to dynamics have common origins.
The second part of this thesis describes the nonlinear effects observed from the application of high direct current (dc) bias fields superposed with a small amplitude sinusoidal ac field. For several molecular glass formers, the application of a dc field was found to slow down the system via reduction in configurational entropy (Adam-Gibbs relation). Time resolved measurements indicated that the rise of the non-linear effect is slower than its decay, as observed in the electro-optical Kerr effect. A model was discussed which quantitatively captures the observed magnitudes and time dependencies of the NDE. Asymmetry in these rise and decay times was demonstrated as a consequence of the quadratic field dependence of the entropy change. It was demonstrated that the high bias field modifies the polarization response to the field, even including the zero field limit.
ContributorsSamanta, Subarna (Author) / Richert, Ranko (Thesis advisor) / Steimle, Timothy (Committee member) / Wolf, George H. (Committee member) / Arizona State University (Publisher)
Created2016
Description
Palladium metal in its various forms has been heavily studied for many catalytic, hydrogen storage and sensing applications and as an electrocatalyst in fuel cells. A short review on various applications of palladium and the mechanism of Pd nanoparticles synthesis will be discussed in chapter 1. Size dependent properties of various metal nanoparticles and a thermodynamic theory proposed by Plieth to predict size dependent redox properties of metal nanoparticles will also be discussed in chapter 1.
To evaluate size dependent stability of metal nanoparticles using electrochemical techniques in aqueous media, a synthetic route was designed to produce water soluble Pd nanoparticles. Also, a purification technique was developed to obtain monodisperse metal nanoparticles to study size dependent stability using electrochemical methods. Chapter 2 will describe in detail the synthesis, characterization and size dependent anodic dissolution studies of water soluble palladium nanoparticles.
The cost associated with using expensive metal catalysts can further decreased by using the underpotential deposition (UPD) technique, in which one metal is electrodeposited in monolayer or submonolayer form on a different metal substrate. Electrochemically, this process can be detected by the presence of a deposition peak positive to the bulk deposition potential in a cyclic voltammetry (CV) experiment. The difference between the bulk deposition potential and underpotential deposition peak (i.e. the UPD shift), which is a measure of the energetics of the monolayer deposition step, depends on the work function difference between the metal pairs. Chapter 3 will explore how metal nanoparticles of different sizes will change the energetics of the UPD phenomenon, using the UPD of Cu on palladium nanoparticles as an example. It will be shown that the UPD shift depends on the size of the nanoparticle substrate in a way that is understandable based on the Plieth model.
High electrocatalytic activity of palladium towards ethanol oxidation in an alkaline medium makes it an ideal candidate for the anode electrocatalyst in direct ethanol based fuel cells (DEFCs). Chapter 4 will explore the poisoning of the catalytic activity of palladium in the presence of halide impurities, often used in synthesis of palladium nanoparticles as precursors or shape directing agents.
To evaluate size dependent stability of metal nanoparticles using electrochemical techniques in aqueous media, a synthetic route was designed to produce water soluble Pd nanoparticles. Also, a purification technique was developed to obtain monodisperse metal nanoparticles to study size dependent stability using electrochemical methods. Chapter 2 will describe in detail the synthesis, characterization and size dependent anodic dissolution studies of water soluble palladium nanoparticles.
The cost associated with using expensive metal catalysts can further decreased by using the underpotential deposition (UPD) technique, in which one metal is electrodeposited in monolayer or submonolayer form on a different metal substrate. Electrochemically, this process can be detected by the presence of a deposition peak positive to the bulk deposition potential in a cyclic voltammetry (CV) experiment. The difference between the bulk deposition potential and underpotential deposition peak (i.e. the UPD shift), which is a measure of the energetics of the monolayer deposition step, depends on the work function difference between the metal pairs. Chapter 3 will explore how metal nanoparticles of different sizes will change the energetics of the UPD phenomenon, using the UPD of Cu on palladium nanoparticles as an example. It will be shown that the UPD shift depends on the size of the nanoparticle substrate in a way that is understandable based on the Plieth model.
High electrocatalytic activity of palladium towards ethanol oxidation in an alkaline medium makes it an ideal candidate for the anode electrocatalyst in direct ethanol based fuel cells (DEFCs). Chapter 4 will explore the poisoning of the catalytic activity of palladium in the presence of halide impurities, often used in synthesis of palladium nanoparticles as precursors or shape directing agents.
ContributorsKumar, Ashok (Author) / Buttry, Daniel A. (Thesis advisor) / Gould, Ian R. (Committee member) / Ghirlanda, Giovanna (Committee member) / Arizona State University (Publisher)
Created2016
Description
ABSTRACT
The objective of this dissertation is to identify a recommended balance between
leadership and management activities of a project manager who aims to rehabilitate a distressed construction project.
The data for this research was collected from 338 construction project professionals belonging to fifteen large construction companies who participated in leadership seminars originated by professors from Arizona State University. The seminars contained various leadership games and exercises that were designed specifically to collect data about leadership and management actions taken by the project managers.
The data from one of the games, called “Project from Hell” (PFH), was used in this research. The PFH game presents the participants with a set of fifty-two actions cards written on a deck of game cards and asks them to select the ten action cards they perceive as being most effective for turning a troubled construction project around. Each suit of the deck represents a different category of actions, focusing on either Traditional Leadership (Hearts), Best Value Leadership (Diamonds), Traditional Management (Spades), or Micro- Management (Clubs).
Statistical analysis of the results revealed that only sixteen of the fifty-two actions cards were selected with statistically significant consistency. Of these sixteen actions, six actions were form Traditional Management actions, five were Traditional Leadership actions, and five were Best Value Leadership actions. This rendered a recommended balance of 62% leadership activities vs. 38% management activities for project managers to rehabilitate distressed construction projects. It was also found that the same balance is recommended for the normal condition construction projects. The calculated weighted
i
scores for ranking the sixteen effective leadership and management actions revealed that the five Traditional Management actions are the top-most effective actions. This demonstrates the importance of stand still management actions in rehabilitating in trouble construction projects
The findings were converted into easy to implement guidelines about how project managers can change habits to increase their effectiveness by focusing on the right type of actions.
A generalization of the methodology for interpreting the results of any study based on selection of activities, was also developed.
The objective of this dissertation is to identify a recommended balance between
leadership and management activities of a project manager who aims to rehabilitate a distressed construction project.
The data for this research was collected from 338 construction project professionals belonging to fifteen large construction companies who participated in leadership seminars originated by professors from Arizona State University. The seminars contained various leadership games and exercises that were designed specifically to collect data about leadership and management actions taken by the project managers.
The data from one of the games, called “Project from Hell” (PFH), was used in this research. The PFH game presents the participants with a set of fifty-two actions cards written on a deck of game cards and asks them to select the ten action cards they perceive as being most effective for turning a troubled construction project around. Each suit of the deck represents a different category of actions, focusing on either Traditional Leadership (Hearts), Best Value Leadership (Diamonds), Traditional Management (Spades), or Micro- Management (Clubs).
Statistical analysis of the results revealed that only sixteen of the fifty-two actions cards were selected with statistically significant consistency. Of these sixteen actions, six actions were form Traditional Management actions, five were Traditional Leadership actions, and five were Best Value Leadership actions. This rendered a recommended balance of 62% leadership activities vs. 38% management activities for project managers to rehabilitate distressed construction projects. It was also found that the same balance is recommended for the normal condition construction projects. The calculated weighted
i
scores for ranking the sixteen effective leadership and management actions revealed that the five Traditional Management actions are the top-most effective actions. This demonstrates the importance of stand still management actions in rehabilitating in trouble construction projects
The findings were converted into easy to implement guidelines about how project managers can change habits to increase their effectiveness by focusing on the right type of actions.
A generalization of the methodology for interpreting the results of any study based on selection of activities, was also developed.
ContributorsBehzad, Navid (Author) / Wiezel, Avi (Thesis advisor) / Gibson, Jr., G. Edward (Committee member) / Sullivan, Kenneth (Committee member) / Arizona State University (Publisher)
Created2016
Description
This study examined an adverse effect of an adolescent group intervention. Group interventions represent one of the most economical, convenient, and common solution to adolescent behavior problems, although prior findings from program evaluation studies have suggested that these groups can unexpectedly increase the externalizing behaviors that they were designed to reduce or prevent. The current study used data from a longitudinal, randomized controlled trial of the Bridges to High School / Puentes a La Secundaria Program, a multicomponent prevention program designed to reduce risk during the middle school transition, which has demonstrated positive effects across an array of outcomes. Data were collected at the beginning of 7th grade, with follow-up data collected at the end of the 7th, 8th, 9th, and 12th grade from a sample of Mexican American adolescents and their mothers. Analyses evaluated long-term effects on externalizing outcomes, trajectories of externalizing behaviors across adolescence, and potential mediators of observed effects. Results showed that the adverse effect that was originally observed based on adolescent self-report of externalizing symptoms at 1-year posttest among youth with high pretest externalizing symptoms was not maintained over time and was not reflected in changes in adolescents' trajectories of externalizing behaviors. Moreover, neither of the peer mediators that theory suggests would explain adverse effects were found to mediate the relationship between intervention status and externalizing symptoms at 1-year posttest. Finally, only beneficial effects were found on externalizing symptoms based on mother report. Together, these findings suggest that the Bridges intervention did not adversely affect adolescent problem behaviors and that future studies should use caution when interpreting unexpected adverse effects.
ContributorsWong, Jessie Jong-Chee (Author) / Gonzales, Nancy A. (Thesis advisor) / West, Stephen G. (Thesis advisor) / Chassin, Laurie (Committee member) / Dishion, Thomas (Committee member) / Arizona State University (Publisher)
Created2015
Description
A pressing question in public policymaking is how best to allocate decision-making authority and to facilitate opportunities for input. When it comes to science, technology, and environmental (STE) policy decisions, persons impacted by those decisions often have relevant information and perspectives to contribute yet lack either the specialized, technical knowledge or the means by which to effectively communicate that knowledge. Consequently, due to a variety of factors, they are frequently denied meaningful involvement in making them. In an effort to better understand why this is so, and how this might change, this dissertation uses an activity systems framework to examine how three factors mediate the circulation of information in STE public engagement mechanisms.
In this project, I examine the transcripts of a 2015 administrative hearing and community meeting about the Santa Susana Field Lab—a former nuclear- and rocket engine-testing facility 30 miles from Los Angeles, where an experimental nuclear reactor suffered a partial meltdown in 1959. Specifically, I identify (1) who was designated as an "expert" versus a member of "the public," (2) the structural features, and (3) the stylistic features of participants' remarks at these events; and I study how these factors mediated the flow of information at each. To do so, I view "expert" and "public" as what Michael McGee has termed ideographs, and consider the structural and stylistic features that prior scholarship has identified to impact information flow.
Based on my analysis, I theorize that role designations, structural features, and stylistic features work together to mediate whose, what, and how information flows in public engagement mechanisms. Based on my findings, I also suggest that this mediation impacts policy outcomes. As such, I contend that better understanding the relationships among these mediational means, information flow, and policy outcomes is an important step towards developing public engagement mechanisms that most effectively use the relevant knowledge and other insights of all who have a stake in policy decisions.
In this project, I examine the transcripts of a 2015 administrative hearing and community meeting about the Santa Susana Field Lab—a former nuclear- and rocket engine-testing facility 30 miles from Los Angeles, where an experimental nuclear reactor suffered a partial meltdown in 1959. Specifically, I identify (1) who was designated as an "expert" versus a member of "the public," (2) the structural features, and (3) the stylistic features of participants' remarks at these events; and I study how these factors mediated the flow of information at each. To do so, I view "expert" and "public" as what Michael McGee has termed ideographs, and consider the structural and stylistic features that prior scholarship has identified to impact information flow.
Based on my analysis, I theorize that role designations, structural features, and stylistic features work together to mediate whose, what, and how information flows in public engagement mechanisms. Based on my findings, I also suggest that this mediation impacts policy outcomes. As such, I contend that better understanding the relationships among these mediational means, information flow, and policy outcomes is an important step towards developing public engagement mechanisms that most effectively use the relevant knowledge and other insights of all who have a stake in policy decisions.
ContributorsChurg, Emily (Author) / Long, Elenore (Thesis advisor) / Hannah, Mark (Thesis advisor) / Catlaw, Thomas (Committee member) / Arizona State University (Publisher)
Created2016