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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.
121

Essays on Macroeconomic Expectations:

Gáti, Laura January 2021 (has links)
Thesis advisor: Ryan Chahrour / This dissertation consists of three independent explorations of the interplay between expectations and macroeconomic activity. I investigate economic dynamics and policy issues concerning the management of expectations both from the lens of business cycles and medium-term fluctuations, embracing a rational expectations approach as well as venturing into the wilderness of bounded rationality. The first chapter, "Monetary Policy & Anchored Expectations - An Endogenous Gain Learning Model," investigates how a concern to anchor expectations affects the conduct of monetary policy. The chapter first proposes a novel model of expectations which provides a notion for unanchored expectations. In this model, expectations are the more unanchored the higher the sensitivity of long-run inflation expectations to short-run fluctuations. I then embed the expectations model in a general-equilibrium model of the business cycle, and estimate the extent of unanchoring using data on inflation expectations. Within the context of the thus calibrated model, I derive the Ramsey-optimal monetary policy. The main result is that it is optimal for a central bank to anchor inflation expectations to the inflation target. The way the central bank can achieve this is by responding very aggressively with its interest rate tool to fluctuations in long-run inflation expectations. The observation that motivates the second chapter, "Talking in Time - Dynamic Central Bank Communication," is that the management of expectations by the monetary authority is a dynamic problem in two ways. Firstly, in a dynamic economy, a central bank needs to decide when to communicate. Secondly, every time the central bank does talk to the public, it also has to choose what to talk about: the present or the future? The chapter thus extends existing macroeconomic research on various dimensions of optimal central bank communication by asking what the implications of dynamics are for the optimal information provision of the central bank to the public. To this end, I analyze a Bayesian Persuasion game between a central bank and the private sector in a static and a dynamic setting, in which the private sector tracks one economic variable, while the central bank wishes it to track a second variable instead. Importantly, the two problems are identical except for the correlation structure between the two variables, which is either cross-sectional or temporal. This way, I isolate the role of dynamics for the optimal communication policy. The main result is that in the dynamic setting, the prior beliefs of the private sector become endogenous to central bank communication and dampen the effectiveness of the central bank's communication. Therefore, the central bank faces a new tradeoff: it needs to push against priors in two ways. Relatively to the static solution, the central bank talks more about the economic variable it wants the private sector to learn about, and it also talks with less clarity in order to render the private sector's beliefs sufficiently responsive to its messages at each point in time. In the third chapter, "ICT-Specific Investment Shocks and Economic Fluctuations - Evidence and Theory of a General-Purpose Technology," joint with Marco Brianti, I explore empirically the role of information and communication technologies (ICT) for medium-run economic fluctuations. The first set of results demonstrate the hump-shaped dynamics of total factor productivity after an innovation in ICT, as identified in a structural vector autoregression context. I interpret the hump-shaped impulse response as a consequence of the slow diffusion of ICT technologies, and test this hypothesis using an estimated two-sector growth model. The second set of results document that, viewed through the lens of the model, the data favor the interpretation of innovations in the ICT-sector playing the role of a general-purpose technology. In other words, the slow buildup of the overall effect on productivity stems from the gradual diffusion of ICT in the economy. / Thesis (PhD) — Boston College, 2021. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Economics.
122

Exploring the Effect of an eHealth Intervention on Women’s Physical Activity Behaviour: A Randomized Trial

Black, Melissa 10 January 2020 (has links)
The rising number of women who are overweight or obese living in Canada is concerning because an excess weight can lead to serious health problems. Nearly 65% of women living in Canada are considered overweight or obese. Regular physical activity (PA) participation is beneficial and can help women manage their weight. Considering women who are overweight or obese are generally physically inactive, interventions drawing on theory are warranted to promote PA. This thesis reports on the protocol and results of a randomized controlled trial that was conducted to assess the effect of a self-determination theory-based eHealth intervention on PA among women who were overweight or obese with low levels of PA. The full protocol for this study is described in Chapter 3: Protocol Manuscript and the results of the primary objective are presented in Chapter 4: Results Manuscript. Reflections on the lessons I have learned while implementing a clinical trial are presented in Chapter 5: Lessons Learned. Briefly, the selfdetermination theory-based eHealth intervention provided (A) six weekly behavioural support emails, (B) a wearable activity tracker, and (C) a copy of the Canadian PA guidelines. The primary objective of this study was to determine if participants who received the combined intervention (A+B+C) increased their PA levels from baseline to post-intervention. The secondary objective was to assess if this combined intervention leads to greater change in PA than those who received an intervention including (B+C) or only (C). It was hypothesized that participants in the combined intervention would increase their PA from baseline to postintervention, and that this increase would be greater than the increase observed among those who received an intervention including (B+C) or only (C). In addition, measures of constructs embedded in self-determination theory (i.e., basic psychological need satisfaction and thwarting, motivational regulations) and wellbeing (i.e., affect, vitality, wellbeing) were included to address tertiary objectives of examining if there are differences in changes in these constructs between groups. Participants were recruited between September 2018 and March 2019. Data were collected using self-report and direct measures three times: at baseline (week 0), postintervention (week 7), and at follow-up (week 21). Data from forty-six women (Mage=37.72±11.87 years, MBMI=31.55±5.96 kg/m2 ) were analyzed. Mean PA at baseline across all participants was 1148.12±1091.03 metabolic equivalent minutes (MET-minutes) per week. In relation to the primary study objective, PA increased from baseline to post-intervention (F=17.95, p.05) and the interaction between group and time (p>.05) were not significant. In summary, participants in this study showed a large and significant increase in PA, but the three different interventions did not have a differential impact on change in PA. Discussion of the findings regarding the primary and secondary objectives, and the potential implications of the tertiary objective, will provide insight into which combination of intervention components may be more effective at promoting PA among insufficiently active women who are overweight or obese, and thus inform the design of future interventions aiming to promote PA.
123

Identification and Genetic Characterization of Antimicrobial Activities of Pseudomonas Mississippiensis, A Novel Bacterial Species Isolated from Soybean Rhizosphere

Jia, Jiayuan 09 December 2016 (has links)
An aerobic, Gram-negative, rod shaped and polarlagellated bacterium, designated strain MS586, was isolated from soybean rhizosphere in Mississippi. The taxonomic position of MS586 was determined using a polyphasic approach. Analysis of the housekeeping genes supported the novel position of MS586. The results were also supported by average nucleotide identity (ANI) values. Based on these data, it is proposed that strain MS586 represents a novel species, Pseudomonas mississippiensis, within the genus Pseudomonas. The type strain is MS586. Strain MS586 showed a broad-spectrum of antimicrobial activity against plant pathogenic bacteria and fungi that are economically important in agriculture. Preliminary studies using transposon-based mutagenesis showed that the gltB gene was associated with production of antifungal activity against the indicator fungus Geotrichum candidum. The research findings of strain MS586 have provided insights into its potential use as a biocontrol agent in plant disease management.
124

Objective Assessment of Physical Activity in Adults with Down Syndrome

Curtis, Jasmine Symone 07 May 2016 (has links)
The purpose of this study was to examine whether cut-points developed for the general population provide different estimates of physical activity (PA) levels in adults with Down syndrome (DS) compared to cut-points developed specifically in adults with DS. This study also attempted to objectively measure the PA levels of adults with DS and to determine if they meet the recommended amount of PA to obtain health benefits. Thirteen adults with DS wore an accelerometer to determine time spent in moderate, vigorous, and moderate-to-vigorous PA. Results indicated that different sets of cut-points responded differently in classifying moderate and vigorous PA levels, as well as in classifying whether participants met the recommended amount of PA for health benefits, as evidenced by the different estimates of moderate-to-vigorous PA in 10 minute bouts. Results also indicated that population specific cut-points should be used for assessment of PA levels in persons with DS.
125

Tracking of Physical Activity and Fitness in Preschool Children

Caldwell, Hilary A.T. 11 1900 (has links)
The early years are characterized by dramatic growth and the development of healthy behaviours, such as physical activity (PA). The objectives of this thesis were to assess one year tracking of fitness and PA in preschoolers and to investigate the relationship between fitness and PA over a one-year period. Four hundred preschoolers (201 boys, 199 girls; 4.5±0.9 years) participated in year 1 and year 2 assessments, 12.1±0.7 months apart. Height and weight were measured to calculate body mass index (BMI) and body fat percentage (%BF) was assessed with bioelectrical impedance analysis (BIA). Two components of fitness were assessed: short-term muscle power (STMP) with a 10-second modified Wingate Anaerobic Test, and aerobic fitness with the Bruce Protocol progressive treadmill (TM) test. Peak Power (PP) and Mean Power (MP) were measures of STMP. TM time and 60-sec heart rate recovery (HRR) were indicators of aerobic fitness. PA data were collected for 7 days with ActiGraph accelerometers, and PA was quantified as the % of wear time (%WT) spent in moderate-to-vigorous PA (MVPA) and vigorous PA (VPA). At year 2, participants were significantly heavier (year 1: 17.9±3.2; year 2: 20.3±3.8kg; p=0.000) and taller (year 1: 106.6±7.8; year 2: 113.5±7.8 cm; p=0.000). From year 1 to year 2, BMI decreased from 15.7±1.3 to 15.6±1.4 m/kg2 (p=0.008) and %BF decreased from 23.2±4.6 to 21.1±4.7% (p=0.000). Both PP and MP improved approximately 30 Watts (p=0.000) from year 1 (PP: 94.1±37.3; MP: 84.1±30.9) to year 2 (PP: 125.6±36.2; MP: 112.3±32.2). TM time increased 2.4±1.4 minutes (p=0.000) from 9.4±2.3 to 11.8±2.3 minutes and HRR was unchanged at 65±14 beats per minute (bpm). MVPA increased from 13.3±2.9 to 13.9±3.0 %WT (p=0.003) and VPA increased from 5.8±1.7 to 6.3±1.8 %WT (p=0.000). PP and MP tracked moderately to substantially (PP: r=0.89, κ=0.61; MP: r=0.86, κ=0.56). TM time and HRR tracked fairly to strongly (TM time: r=0.82, κ=0.56; HRR: r=0.52, κ=0.23). MVPA and VPA tracked fairly to moderately (MVPA: r=0.59, κ=0.28; VPA: r=0.37, κ=0.38). At year 1 and year 2, PP, MP and HRR were weakly correlated to PA variables (r=0.13-0.23, p=0.000-0.02). TM time was correlated to VPA at year 1 (r=0.131, p=0.016) and to MVPA and VPA at year 2 (r=0.12-0.15, p=0.006-0.023). Boys engaged in more MVPA at year 1 and year 2 (p=0.000). Boys and girls were separately divided into groups that decreased, maintained or increased MVPA or VPA from year 1 to year 2. Girls who maintained MVPA had higher weight %iles and %BF than girls who increased MVPA, at both year 1 and year 2. Boys who increased VPA saw a greater increase in HRR than those who maintained VPA (p=0.000). Our findings indicate that fitness tracks better than PA over a 12-month period during the early years, and that a weak, positive relationship between these variables exists. Other factors, including measures of body composition, are likely influencing these relationships. / Thesis / Master of Science in Kinesiology
126

Understanding the Role of Cues in Predicting Physical Activity Behavior

Jochim, Alexander 06 1900 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Cues have been theorized to promote health behaviors but currently our understanding of the effectiveness of cues is inconclusive. The purpose of this systematic review was to assess the effectiveness of cue interventions in promoting physical activity (PA). Six databases were searched which captured 3,996 articles. After comparison with the eligibility criteria, 19 articles were included in the review. Data extraction revealed that while cues were effective in increasing PA behavior, less than half of the studies (n = 8) were supported by theory-based methodologies. We concluded that cue-based interventions are effective for promoting PA behavior, but future research must develop valid measures of cues and incorporate theory into their study designs. The purpose of the thesis study aimed to address this gap by testing if cue consistency would help explain PA habit and behavior through the Dual Process approach. We conducted an observational study with two measurement periods. We recruited 196 participants via an online volunteer registry. Participants completed measures of exercise behavior, intention, habit, perceived behavioral control (PBC), affective attitudes, and cue consistency at baseline and one month later. We ran a Hierarchical Multiple Regression analysis to determine whether a) habit, intention, PBC, affective attitudes, and cue consistency predicted moderate-vigorous physical activity (MVPA) and b) whether PBC, affective attitudes, and cue consistency predicted habit. Our results showed that MVPA was significantly predicted by habit (β = 0.23, p < 0.01), intention (β = 0.16, p < 0.05), PBC (β = 0.23, p < 0.01), affective attitudes (β = 0.20, p < 0.05), and cue consistency (β = -0.20, p < 0.05). Habit was predicted by affective attitudes (β = 0.48, p < 0.001) and cue consistency (β = 0.32, p < 0.001), but PBC (β = 0.10, p = 0.11) was not significant. We found a stronger relationship between cue consistency and habit than previous studies that evaluated cues individually, supporting the cue consistency construct. Our results suggest that cue consistency should be incorporated in the Dual Process approach as a determinant of habit. Future research should look to replicate our findings through cue-based interventions grounded in theory.
127

Minding the Gap: Understanding changes in momentary intentions and physical activity behaviours during late adolescence using ecological momentary assessment / Variation in daily and within day intentions and the intention-behaviour gap

Dutta, Pallavi January 2020 (has links)
BACKGROUND: The construct of intention continues to be an important correlate and predictor of physical activity; however, a substantial intention behaviour gap continues to exist. Little literature has examined this gap on a micro-temporal scale, and none have addressed the adolescent population. PURPOSE: The purpose of this thesis is to 1) examine whether there are variations in daily and within day intentions to be physically active in the adolescent population, and 2) whether the intention -physical activity gap is reduced when assessing intention and behaviour on a micro-temporal scale using Ecological Momentary Assessment (EMA). METHODS: This thesis sample included 193 grade 11 students from a large school board in Southern Ontario. Participants responded to 5 EMA prompts for 7 days on their smartphones and wore accelerometers for the duration of the study. Each EMA prompt included a brief questionnaire assessing participant intentions to engage in physical activity. A mixed-effects logistic regression model was used to determine variability in intentions and descriptive analyses were used to examine the intention - behaviour gap. RESULTS: A mixed-effects logistic regression did not indicate differences in intentions between days of the week (coef. = -0.07 SE: 0.07, p=.27) but did indicate that likelihood of reporting intentions significantly decreases over the course of the day (coef. = -.479 SE=.05, p<.01). For daily intentions and physical activity, 89% of daily intenders engaged in subsequent physical activity while 46% of within day intenders engaged in subsequent physical activity. CONCLUSIONS: Findings suggest that there is some variation in intentions and that a micro-temporal time scale measurement serves to reduce the intention - behaviour gap. This adds to our understanding of the relationship between intentions and physical activity. In better understanding this relationship, we can begin to guide interventions that bridge the gap between intentions and physical activity in the adolescent population. / Thesis / Master of Science (MSc) / Despite the known benefits of physical activity, rates remain low amongst adolescents. Previous research has outlined the importance of intentions as a predictor of physical activity; however, an intention behaviour gap persists. The current study examined this gap by assessing variation in intentions over the course of the week and day, and by examining intentions and physical activity closer together in time through the use of a smartphone app. Significant variation was found in intentions within the day to engage in activity. Descriptively assessing intentions and physical activity by measuring them closer together in time indicated a reduction in the daily intention behaviour gap but no significant differences between intentions and behaviour measured frequently within a day. Findings suggest that the intention to behaviour gap may be reduced by assessing intentions and behaviour more frequently and closer together in time. Further research is required to quantify this reduction.
128

Activity Recognition using Singular Value Decomposition

Jolly, Vineet Kumar 09 November 2006 (has links)
A wearable device that accurately records a user's daily activities is of substantial value. It can be used to enhance medical monitoring by maintaining a diary that lists what a person was doing and for how long. The design of a wearable system to record context such as activity recognition is influenced by a combination of variables. A flexible yet systematic approach for building a software classification environment according to a set of variables is described. The integral part of the software design is the use of a unique robust classifier that uses principal component analysis (PCA) through singular value decomposition (SVD) to perform real-time activity recognition. The thesis describes the different facets of the SVD-based approach and how the classifier inputs can be modified to better differentiate between activities. This thesis presents the design and implementation of a classification environment used to perform activity detection for a wearable e-textile system. / Master of Science
129

Levels of Cultural Activity: Differences by Type of Roommate

Minson, Holly Anne 05 May 2000 (has links)
One recent trend in colleges and universities across the nation is the internationalization of higher education. This internationalization has taken form in two different areas: (a) the curriculum and (b) the co-curriculum. The curricular realm has responded by offering additional or new programs in languages and area studies as well as opportunities to study abroad. The co-curricular realm has also responded in the construction of international centers, and the development of international-style programming and international theme housing. One component of the co-curricular realm, international theme housing, has enabled American students to experience a living arrangement with a cross-cultural focus. Researchers have explored the impact this type of arrangement can make in the lives of students during their college career. However, no extensive research has been conducted to see if a connection can be made between roommate pairings and cultural activity. The purpose of this study was to examine the cultural activity of two groups of American students. Cultural activity was defined in this study as: (a) a focus on international issues in academic work, (b) establishing and maintaining relations with non-American people, and (c) participating in events with an international theme. The two groups of students included Americans with International Roommates and Americans with non-International Roommates. The study compared the levels of cultural activity between participants in the two groups. To discover the differences in cultural activity between these two groupings of students, a series of logs were created for participants to record their daily activities. These logs included sections for participants to record classes, assignments in classes, use of media, social interactions, and social activities. The researcher recruited 30 participants (15 participants with an international roommate and 15 participants with a non-international roommate) to complete these logs. Data were collected over a two-week period. Participants were also asked questions in an exit interview. Results revealed only limited differences in the levels of cultural activity between the two groups. The findings suggest that living with an international student does not promote higher levels of cultural activity among American college students. / Master of Arts
130

Association of Physical Activity and Sedentary Behavior among obese adolescents across ethnicity: Examination of 2007-2012 NHANES data.

Samaraweera, Tharushi 07 May 2016 (has links)
Introduction: The prevalence of childhood and adolescent obesity in the U.S. and in other countries has continued to rise over the last several decades. Health behaviors such as physical activity and inactivity patterns have been shown to influence rates of obesity among adolescents. Racial/ethnic disparities related to adolescent obesity have been recognized through existing research, and differences in socioeconomic and cultural backgrounds have been noted as possible contributing factors to the risk of adolescents becoming overweight or obese. The primary purpose of this study was to analyze the association of physical activity and sedentary activity with obesity prevalence among adolescents aged 12-15 years old across ethnic groups in the U.S. Methods: This study utilized data from the combined 2007-2012 National Health and Nutrition Examination Survey (NHANES). Descriptive characteristics of the study population were analyzed for both ethnicity and BMI status, and Chi-square tests were used to assess differences among the variables. The association between BMI status categories and ethnicity were evaluated. A univariate analysis was conducted to evaluate the association of the independent and covariate variables with obese status among adolescents. A multivariable logistic regression was also performed to determine the association between BMI status and physical activity, controlling for the covariate variables. For sedentary activity, the frequency statistics were analyzed between each of the ethnicities and BMI status, and t-tests were conducted to determine statistical significance. Results: The sample size for this population included 939 adolescents. Approximately 40% of adolescents were categorized as obese, according to age- and sex-specific BMI percentiles. Among ethnicity, Non-Hispanic white adolescents had the greatest prevalence of obesity, compared to Non-Hispanic Black and Mexican-American adolescents. There was not significant association between BMI status and demographic characteristics, including ethnicity, in the sample. Regarding physical activity, there was some indication that those who engaged in moderate and vigorous physical activity were less likely to be obese, however these findings were not found to be significant. Non-Hispanic black obese adolescents reported significantly less moderate activity compared to Non-Hispanic white adolescents(p=0.02). Obese adolescents in this sample had reported slightly less mean sitting time per day, compared to those who were not obese. Conclusion: Although the findings of this analysis showed some indication of differences in physical activity and sedentary behavior patterns among obese adolescents, the overall findings did not provide a statistically significant association between the variables and ethnicity. Further studies related to this topic could analyze differences in cultural and social norms across ethnicities that could influence physical activity behaviors in adolescents. Also, access to exercise facilities and differences in dietary behaviors among adolescents could be considered.

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