21794 research outputs found
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Weighing The Mind: Cognitive And Emotional Influences On Weight Loss Maintenance In Obesity
Get PDFObesity is a multifaceted and complex disease. Weight loss in efforts to combat obesity often result in weight regain, posing a significant challenge to long-term weight management. This dissertation investigates the cognitive, emotional, and physiological factors contributing to weight loss maintenance, emphasizing the roles of eating behaviors, depressive symptoms, and inflammation. In a retrospective cohort study, data was collected on individuals enrolled in the Michigan Weight Management Program who consented to involvement in this research. The data was collected at baseline, post-weight loss (after 10% weight loss at 6 months), and on one-year and two-year follow-ups. The Yale Three Factor Eating Questionnaire was used to measure cognitive restraint, uncontrolled eating and emotional eating. Depressive symptoms were measured using the Inventory of Depressive Symptomatology-Self Report (IDS-SR). Serum inflammatory markers (IL-1β, IL-6, IL-8 and TNF-α) were analyzed. Statistical analyses included the use of general linear models, hierarchical logistic regression, repeated measures ANOVAs and post-hoc analysis. In the eating behaviors cohort, 51 participants out of 109 were categorized as Maintainers. Maintainers had higher cognitive restraint, lower uncontrolled and emotional eating at the one-year follow-up. Uncontrolled eating in Regainers reverted toward baseline levels during the maintenance phase. However, the overall predictability of our model was less than chance. In the depressive symptomatology cohort, 118 participants of 230 were categorized as Maintainers. Depressive symptoms decreased with weight loss and were sustained throughout the maintenance phase. Females had significantly higher depressive symptomatology scores than males and female Regainers had higher scores than female Maintainers. In the inflammatory cohort, 25 of 57 participants were categorized as Maintainers. IL-8 and TNF-α were different between Maintainers and Regainers after weight loss. IL-1β, IL-8 and TNF-α levels were associated with depressive symptoms. Particularly TNF-α at post-weight loss was a predictor of IDS-SR scores after the maintenance phase. This research emphasizes the role of eating behavior, depressive symptoms and inflammatory processes in weight loss maintenance. The results highlight the importance of CR and UE, gender-specific differences with depressive symptoms and inflammatory markers and their relationship to weight loss maintenance. These findings can aid in the improvement of a more tailored approach to obesity treatment and management
How Employee Motive Attributions Shape The Relationship Between Internal Corporate Social Responsibility And The Psychological Contract: The Impact On Employee Burnout And Work Engagement
No full textThis dissertation built a framework that bridged the literature on CSR, motive attributions, and psychological contract theory to address key shortcomings in these areas and further integrate these literatures. In the first step, I conducted the first cross-disciplined systematic review of the employee attribution of CSR literature. The review consolidated 41 studies, which utilized multiple attribution frameworks and spanned several research disciplines. A key finding of this review highlights the inconsistent impact of negative attributions, which I theorize is due to the contents of the measurement scales. Additionally, I draw attention to the inconsistency in the terminology used across studies, which will stunt the development of research in this area. In total, I offer five recommendations for future research. Next, I utilized a JD-R theory framework to introduce a psychological contract perspective on how an organization’s internal CSR initiatives impact its employees. As internal CSR initiatives (i.e., organizational actions targeting employee well-being) have experienced widespread adoption, employees now view their organizations as obligated to offer these initiatives and the resources they provide, making them an element of the psychological contract. As resource delivery mechanisms, internal CSR initiatives offer the socioemotional and ideological resources obligated of the organization in the psychological contract. By offering these resources, organizations fulfill the psychological contract of employees, with a fulfilled psychological contract itself acting as a resource that partially transmits the effects of internal CSR initiatives, increasing work engagement and decreasing burnout Testing this framework in a large sample of employees from across the USA, I found robust support for this chain of relationships. Additionally, it was proposed, but ultimately not supported, that motive attributions would act as boundary conditions for these relationships. Employees are burnt out and increasingly care about how they are treated by their employer, with displeasure in treatment leading to mass withdrawals in their engagement, causing current phenomena such as “quiet quitting” and the “great resignation”. Internal CSR initiatives (e.g., employee wellness, work-life balance, DEI) directly address these issues and have become a key part of the employee-employer relationship
Development Of A Reliability Based Design Optimization Framework For Typical Steel Bridge Structures Subjected To Blast Loads
No full textThis research focuses on developing and implementing a reliability-based design optimization (RBDO) approach for a steel girder bridge to minimize construction cost while allowing the structure to meet a specified reliability level under blast load. The blast resistance of a typical two-lane steel girder highway bridge structural system was modeled using a nonlinear finite element approach that considers material damage, fracture, and separation. Critical blast scenarios, based on field observations of terrorist attacks on bridges in Iraq, were assessed to define system failure in terms of practical emergency serviceability criteria. The study varied various design parameters, such as the number of girders, deck concrete strength, reinforcement ratio, slab thickness, girder and reinforcement yield strength, girder sectional dimensions, and pier column width, to evaluate blast resistance. The RBDO process adjusted design variables including the number of girders, yield stress, flange width, flange thickness, web thickness, web depth, and deck thickness to maintain a specific reliability index for blast resistance.A reliability model was developed for the probabilistic assessment of the bridge. A response surface was developed to model critical girder end displacement for use in the limit state function. Sensitivity analysis indicated that the system\u27s blast capacity and reliability were primarily influenced by the number of girders and girder yield strength, with additional significant parameters including deck compressive strength, deck thickness, web stiffener width, and girder depth. Secondary parameters were deck reinforcement ratio and girder flange and web thickness, while deck reinforcement yield stress was found to be insignificant. The results show that the RBDO balances structural integrity and cost by adjusting bridge geometric and material strength design parameters, reliability index, and steel/concrete cost ratio. Effective increases in steel girder bridge blast reliability can be achieved by using smaller girder spacing, higher yield strength girders with lower depth, and a deck with lower compressive strength but greater thickness. This study provides recommendations for improving blast resistance and cost-effectiveness in steel girder bridge design
The Cohomology Of The Extended Morava Stabilizer Group, With Trivial Coefficients, At Large Primes
Get PDFThe goal of this thesis is to calculate the cohomology of the extended height n Morava stabilizer group, with trivial coefficients, for all heights n and all primes p\u3e\u3en. To do this, we construct a family of deformations – parametrized over an affine line and smooth away from a single point – of Ravenel\u27s Lie algebra model for the Morava stabilizer group. The singular fiber of the resulting bundle of differential graded algebras is the Chevalley-Eilenberg DGA of Ravenel\u27s Lie algebra model, while the smooth fibers have very understandable cohomology. From here, tools such as parallel transport, connections, and a derived version of the local invariant cycles theorem are used to compare the cohomology of the singular fiber with the cohomology of any smooth fiber. Among our conclusions is an isomorphism, for all heights n and all primes p\u3e\u3en, between the cohomology ring of the extended height n Morava stabilizer group with trivial coefficients, and the cohomology of the unitary group of degree n with coefficients in the finite field with p elements. This isomorphism verifies a long-standing conjecture in stable homotopy theory
Imaging And Modeling Multi-Photon Dynamics In Atoms And Surfaces
No full textThe demand for innovative technologies has grown exponentially year by year. In recent years, advances in the field of laser spectroscopy have revealed nuclear and electronic dynamics that have not been available previously. 3D momentum imaging has been a powerful tool used in ultrafast science studying photoionization/dissociation processes in gas phase. We have extended the use of 3D momentum imaging in analyzing solids/surfaces. We achieved a ~ 64 ps timing resolution in measuring time of flight (TOF) with the new 3D momentum imaging apparatus, which is well suited to perform electron and ion imaging. We utilized the newly implemented 3D momentum imaging apparatus to study the mechanism of MALDI primary ionization. Despite being one of the widely used tools in analytical chemistry, its primary ionization mechanism is poorly understood. We experimentally measured the work function and exciton life-time of 2,5-dihydroxybenzoic acid, a commonly employed MALDI matrices. From these results, we determined that multi-photon ionization plays a dominant role in primary ionization in MALDI.Furthermore, even though people speculated that in MALDI, negative ions are formed via electron attachment in the plume, there was no direct experimental evidence. We implemented a high-voltage pulsing scheme to control the electron emission time into the plume. We demonstrated that delaying the electron emission enhances the formation of negative ions and showed the timing characteristic of electrons involved in forming negative ions. Finally, the role of resonance is often overlooked in tunneling ionization, especially in attoclock studies. Here, we theoretically investigated the effect of resonance on the attoclock deflection angle. We observed in argon that a resonance between the Rydberg states can have a significant impact on the deflection angles. This observation suggests that the interpretation of attoclock experiments have to include the effect of resonance
Adolescent Close Relationship Quality, Racial Trauma, And Mental Health Outcomes
No full textExperiencing racial trauma is, unfortunately, fairly common for African Americans in the United States (Bleich, 2019; Seaton & Douglass, 2014). For African American adolescents, racial trauma can result in lasting mental and behavioral problems such as depression, suicidal ideation, and engaging in risky behaviors (Bernard et al., 2022; Jelsma et al., 2022; Madubata et al., 2022). Fortunately, there is evidence that positive relationships between adolescents and their peers and caregivers can protect youth against harmful events (Eisman, 2015; Yearwood et al., 2019). The current study examined the relationship between racial trauma, adolescent close relationship quality, and mental and behavioral health outcomes. Peer-adolescent relationship quality moderated the relationship between racial trauma and behavior problems. For youth with high levels of racial trauma, those who have better relationships with their peers reported few behavioral problems. While experiencing racial discrimination may be common for African American youth, fostering quality relationships with peers may be a path forward in protecting against the adverse outcomes of racial trauma
Development Of Advanced Multi-Nozzle Multi-Material 3d Printing
No full textExtrusion-based 3D printing methods, such as Direct Ink Writing, are extensively utilized across sectors like biomedical, energy, and electronics, employing a diverse range of materials. However, the lengthy printing times associated with single-nozzle systems limit their application in complex mass production and rapid prototyping. While multi-nozzle systems have attempted to address this issue, they often result in costly, and bulky setups with limited material options. This research introduces a novel multi-nozzle multi-material system that allows for simultaneous 3D printing using bent nozzles. The system is cost-effective, simple in design, and capable of printing a wide range of materials. Its universal design enables its integration with the commercially available printers and can reduce printing time by up to 90%. The capabilities of the multi-material setup are demonstrated through the 3D printing of soft, variable-stiffness elastomers for biomimetic robotic applications. Due to the rapid curing of elastomers in additive manufacturing, the change in mechanical properties of the 3D printed material were experimentally characterized. 3D printed ecoflex 00-10, Dragon skin 20, and a combination of both in layered format were evaluated. We then determined material parameters for incompressible hyperelastic strain energy function using the Mooney-Rivlin model (2nd, 3rd, and 5th order) and the Yeoh model (2nd and 3rd order). The Mooney-Rivlin model showed better alignment with experimental data, and these parameters were used to validate the results in ANSYS simulations. A fully 3D printed 100% elastomeric biomimetic octopus arm with gradient stiffness was successfully fabricated. A comparative study was conducted between the 100% elastomeric arm and an identical arm design integrated with metallic spring steel for controlled stiffness gradient. The elastomeric arm demonstrated controlled bending similar to the non-elastomeric version, validating the potential for 3D printing functionally gradient stiffness elastomers for robotic applications. Additionally, the developed model was used to predict the arm’s deformation through actuation via ANSYS simulation, which also aligned well with experimental results. Furthermore, this dissertation investigates the impact of printing parameters on oozing, a common problem affecting print quality in direct ink writing. The newly developed system, along with the parameter characterization, and oozing study, makes the multi-nozzle systems more affordable and capable of printing advanced material combinations with improved print quality. This breakthrough in additive manufacturing opens new avenues for fabricating entirely soft robotic structures with controlled variable stiffness configurations, offering better deformation control and improved functionality in high pressure environment, where the integration of rigid components presents significant challenges
Perceptions of Substance Use and Sexual Risk Behaviors Among Adolescent Women Involved in Juvenile Justice
Get PDFCHOICES-TEEN is a bundled intervention aimed at reducing the risks of unintended pregnancy, sexually transmitted infections, and alcohol- and tobacco-exposed pregnancies for adolescent girls involved in the juvenile justice system. We examined youths’ (N = 22) elicited pros and cons concerning alcohol, tobacco, condom, and contraception use to inform future iterations of CHOICES-TEEN and other prevention programming during a one-arm pilot study. Content analysis was used to identify recurring themes elicited and recorded during a decisional balance exercise with a counselor. The most recurrent pros and cons were factors that directly affected these adolescents, with more immediate consequences. The results provide insight into motivations for engaging in substance use and risky sexual behaviors for these youth, as well as barriers to change
“Inviting people into our experience in a powerful way”: Indigenous Representation in the Television Series Burden of Truth and Midnattssol
No full textIntroducing diversity into the white-dominated media business is part of mainstreaming social justice movements. This article addresses Indigenous themes’ and talents’ inclusion in two television series by mainstream production companies from the perspectives of organic representation, inclusivity, and justice. The analysis focuses on Canadian legal drama Burden of Truth (2018–2021) and French-Swedish Nordic Noir Midnattssol (Midnight Sun, 2016). It considers the participation of Indigenous talents and their realistic address of social concerns and argues that both series work within the constraints of their political economies while offering modes for representation that demonstrate possibilities for creating inclusive and socially impactful, yet entertaining, productions
