Search results

Title: ENGINEERING HUMAN ADIPOSE TISSUE WITHIN A MICROFLUIDIC DEVICE
Creator: Yang, Feipeng
Date: 2019
Description: Adipose tissue models can be used for in vitro drug screening of therapeutics designed for the treatment of obesity or adipose tissue-related...
Show moreAdipose tissue models can be used for in vitro drug screening of therapeutics designed for the treatment of obesity or adipose tissue-related diseases. This work aimed to engineer functional three-dimensional (3D) adipose microtissue models that could be incorporated within a microfluidic system. To support the on-chip 3D culture, a microfluidic device consisted of cell culture chambers flanked by two side channels was designed. The mold for the microfluidic device was manufactured using computer numeric control (CNC) micro-milling. Soft lithography with polydimethylsiloxane (PDMS) was used to construct the microchannels and chambers in the microfluidic device. A model was developed by the monoculture of adipocytes within the microfluidic device. Human adipose-derived stem cells (ADSCs) were differentiated toward adipocyte in the cell culture chambers and formed a 3D adipose microtissue. The effect of interstitial flow on the adipogenic differentiation of ADSCs was explored. Adipocytes showed decreased adiponectin secretion and increased lipolysis in response to increased interstitial shear stress. Meanwhile, multiple adipogenic genes were downregulated with the increase in shear stress.To engineer vascularized adipose tissue, a co-culture system with ADSCs, human umbilical vein endothelial cells (HUVECs) and normal human lung fibroblasts (NHLFs) was applied. Culture conditions (media, cell ratios, temporal conditions, etc.) for optimal differentiation of ADSCs and induction of network formation were identified. ADSCs were induced toward adipogenesis before mixed with HUVECs and NHLFs. The cell mixture was loaded into the microfluidic device and formed an adipose microtissue with a vessel network in a mixed culture media. An interconnected vascular network was established within 2 weeks and formed anastomoses with the side channels. Perfusion of fluorescent dextran confirmed the interconnections and lumen formation of the vascular network. Perfusion of fluorescently labeled fatty acid analog through vessels resulted in the accumulation of the fatty acid in adipocytes, confirming the functionality of the adipose microtissue. In conclusion, this work presented adipose tissue models within a microfluidic device that can potentially be utilized for on-chip drug screening, as well as provide insights into the engineering of complex tissues.
Show less

Title: Control Surface Synthesis of Propane Dehydrogenation Catalysts
Creator: Zhao, Yiqing
Date: 2019
Description: Alkane dehydrogenation is one of the primary chemical reactions to convert light alkanes into light olefins. The conversion of small alkanes...
Show moreAlkane dehydrogenation is one of the primary chemical reactions to convert light alkanes into light olefins. The conversion of small alkanes to alkenes by dehydrogenation reactions is important for polymer and chemical industrial process because it makes direct producing the possible alkenes. Controlled synthesis of single-site catalysts are still challenges. This makes tuning of the catalysts structure and active sites difficult. We developed method of Zirconium modified SiO2 to support single-site catalysts. My research is focusing on the synthesis new single-site heterogeneous catalysts for high selectivity alkane dehydrogenation reaction and the general principles to design better preformed catalysts (e.g., more active, more selective, more stable) for dehydrogenation reaction, especially on propane dehydrogenation. The study described in this thesis was conducted to understand how zirconium ions can modify the electronic properties and catalytic performance.In this study, with the Zr promoted cobalt catalysts show high propane conversion and propene selectivity compared to the previous reported Co/SiO2 catalyst by our group previous work. The Co/Zr/SiO2 material exhibited good catalytic activity, stability and high propylene selectivity which can reach up to 97% for catalytic propane dehydrogenation at 550 ℃. The catalyst was characterized by TEM, STEM, EPR, DRIFTS, UV-vis, XANES and EXAFS for synthesized material, under reaction conditions and post reaction samples. We hypothesized the reason behind is due to the π donation of Zr will lead to ease of heterolytic cleavage of the propane by have a lower metal-oxygen bond dissociation energy in the rate-determining step which is consistent with the previous calculations found that weaker catalyst-oxygen bonds led to facile heterolytic cleavage. A varieties of single-site Ga catalysts supported on Zr modified SiO2 were synthesized by different methods. The Ga/Zr/SiO2 catalysts prepared by the difference method also exhibit higher or similar activity and selectivity. Those catalysts have more isolated active sites show that rational catalyst design method, such as surface organometallic chemistry synthesize, can be applied in heterogeneous systems using homogeneous catalyst design method. But the origin of those effects is unclear, some discussion of possible origins of observation of catalysts behavior are discussed in Chapter 4. And we will do more characterization to find the origins behind.
Show less

Title: NUMERICAL ANALYSIS ON MAXIMUM LIKELIHOOD ESTIMATORS FOR LINEAR PARABOLIC STOCHASTIC PARTIAL DIFFERENTIAL EQUATIONS
Creator: Zhang, Jun
Date: 2019
Description: The thesis contributes to the numerical analysis on statistical inference for stochastic partial differential equations (SPDEs). We study the...
Show moreThe thesis contributes to the numerical analysis on statistical inference for stochastic partial differential equations (SPDEs). We study the maximum likelihood estimation problem of the drift parameter for a large class of linear parabolic SPDEs. As in the existing literature on statistical inference for SPDEs, we take a spectral approach, and assume that one path of the first N Fourier modes is observed continuously in a fixed finite time interval [0, T]. We first provide a review of the asymptotic properties of the maximum likelihood estimator (MLE) of the drift parameter in the large number of Fourier modes regime, N  ∞, while the time horizon T > 0 is fixed. The main part of this thesis is dedicated to the numerical study of the asymptotic properties of the MLEs for two examples of linear parabolic SPDEs: the one-dimensional stochastic heat equation and a d-dimensional linear, diagonalizable, parabolic SPDE, where d  ℕ. For the one-dimensional stochastic heat equation, we perform the sensitivity analysis to assess the effect of changes in model parameters on the speed of convergence of the MLE. For the second linear parabolic SPDE, our simulations verify the theoretical results in the literature that both the consistency and asymptotic normality of the MLE hold for such equation only when d ≥ 2.
Show less

Title: Physics at the MeV-Scale in Liquid Argon Time Projection Chambers
Creator: Lepetic, Ivan Thomas
Date: 2020
Description: The liquid argon time projection chamber (LArTPC) is the detection technology chosen for several Fermilab-based neutrino experiments. This...
Show moreThe liquid argon time projection chamber (LArTPC) is the detection technology chosen for several Fermilab-based neutrino experiments. This technology will be used in studies of neutrino cross-sections and oscillations, neutrinos from supernovae as well as a variety of studies of beyond the Standard Model physics. This thesis explores the use of these detectors to study MeV-scale activity. MeV-scale electrons arising from Compton scatters of deexcitation photons and photons from inelastic neutron scattering in neutrino-nucleus interactions are reconstructed using novel methods presented here. This work represents the first demonstration of MeV-scale physics capabilities in a LArTPC neutrino experiment as well as the first observation of neutrino-produced photons from nuclear de-excitation and inelastic neutron scattering. A search for millicharged particles, postulated by theories of beyond the standard model physics, is also performed using data from a LArTPC and the low-energy reconstruction techniques developed. The results set world-leading bounds on the parameter space of millicharged particles. The work in this thesis demonstrates that studies of MeV-scale activity and new physics are possible with LArTPC technology and provides the foundation for future LArTPC studies of low energy neutrinos and new physics.
Show less

Title: Gradient Hydrogels for Neovascularization of Engineered Tissues
Creator: He, Yusheng Jason
Date: 2020
Description: The inability to induce extensive and perfusable microvasculature within complex engineered tissues that possess spatial variations in...
Show moreThe inability to induce extensive and perfusable microvasculature within complex engineered tissues that possess spatial variations in mechanical properties, physical architecture and biochemical composition remains as a major hurdle to their clinical translation. Biomaterial strategies focused on designing scaffolds with physiologically relevant gradients provide a promising means for elucidating 3D vascular cell responses to spatial and temporal variations in matrix properties. This work developed a cell-laden hydrogel platform with tunable decoupled and combined gradients of multiple matrix properties critical for maintenance of long term-vascular cell viability, adhesion, migration and invasion outgrowth to elucidate the impact of gradient matrix cues on 3D neovascularization in culture. This was achieved through the completion of three specific aims. First, a novel ascending frontal polymerization (AFP) technique was developed to generate gradient-based PEG hydrogel scaffolds with tunable individual and combined matrix gradients. Using programmable syringe pumps to control the delivery of precursors with distinct composition during crosslinking, we were able to generate gradient scaffolds with decoupled spatial variations in the immobilized concentration of the RGD cell adhesion peptide ligand and elastic modulus. Using this approach, the slope and magnitude of the imposed RGD gradients were readily manipulated without inducing variations in elastic modulus. Vascular spheroids inserted into gradient hydrogel scaffolds supported 3D vascular sprout formation, while the immobilized RGD gradient promoted an increase in sprout length towards the imposed gradient. Next, to create cell-laden scaffolds photopolymerization conditions were optimized to enable viable cell encapsulation during scaffold fabrication. To achieve this, an experimental sensitivity analysis combined with the design of experiments (DOE) was implemented to design isotropic hydrogel scaffolds with a broad range of matrix properties (elastic modulus, immobilized RGD and proteolytic degradation) that supported vascular sprouting in 3D culture. We examined the individual and interaction effects of each matrix property and demonstrated that an optimal combination associated with increases in immobilized RGD and proteolytic degradation of mediate synergistic enhancements in 3D vascular sprouting. Based on the findings from this in vitro study with isotropic hydrogel scaffolds, we designed scaffolds with 5 types of gradient combinations in immobilized RGD, stiffness and protease-sensitivity and explored the impact of spatial variations these matrix cues on vascular sprouting within the constructs in 3D culture. Specifically, we created hydrogel scaffolds with gradients in immobilized RGD with (1) steep and (2) shallow slopes, (3) gradients in elastic modulus, (4) gradients in protease-sensitivityand and (5) opposing gradients of RGD and modulus and concurrent gradients of protease sensitivity and RGD. By encapsulating vascular spheroids in different regions of each gradient scaffold, we observed spatial variations in total sprout length within all gradient scaffolds. We also found that RGD gradient and combined gradient scaffolds induced biased vascular sprouting toward increased RGD concentration and that biased sprouting was enhanced by gradient magnitude and slopes of immobilized RGD concentration. Conversely, directional sprouting responses diminished in scaffolds possessing opposing gradients in RGD (with concurrent gradients of degradation) and modulus. The presented work is the first to demonstrate the use of a cell-laden biomaterial platform to explore the impact of gradients in RGD, proteolytic degradation, and stiffness on vascular sprouting responses in 3D culture. The presented platform and findings of this thesis work hold great potential in the fields of tissue engineering specifically for prevascularization of complex tissues that possess spatial variations in mechanical properties, degradation rate and adhesion ligand composition to facilitate their regeneration.
Show less

Title: THREE ESSAYS IN ENTREPRENEURIAL FINANCE AND COMMODITY MARKETS
Creator: Jia, Jian
Date: 2020
Description: This dissertation includes three essays with a series of empirical investigations in areas of entrepreneurial finance and commodity markets.In...
Show moreThis dissertation includes three essays with a series of empirical investigations in areas of entrepreneurial finance and commodity markets.In the first essay, I study the impact of General Data Protection Regulation (GDPR) on investment in new and emerging technology firms. My findings indicate negative post-GDPR effect after its 2018 rollout on EU ventures, relative to their US counterparts, but no such effects following its 2016 enactment.In the second essay, I examine how investors’ tendency to prefer investing in local ventures interacts with the effects of the GDPR on venture investment in EU. I demonstrate that GDPR’s enactment and rollout differentially affect investors as a function of their proximity to ventures. Specifically, I show that GDPR’s rollout in 2018 has a negative effect on EU venture investment and the effects are higher when ventures and lead investors are not in the same country or union. The relationship manifests in the number of deals per month and in the amount invested per deal, and is particularly pronounced for newer and data-related ventures.In the third essay, I formulate two claims about spot and futures return prediction in industrial metal futures market. These claims lead to testable hypotheses, and provide theory-based restrictions for the coefficients of spot and futures return regression. I investigate six industrial metals and find empirical support for my hypotheses. The in-sample and out-of-sample evidence shows that financial variables, proxies for global economic activities, and the basis predict futures and spot price returns consistently with my hypotheses. Furthermore, my out-of-sample trading experiments document economic significance of the restrictions.
Show less

Title: Gas Turbine Vane Heat Transfer and Cooling Under Freestream Turbulence
Creator: Kanani, Yousef
Date: 2020
Description: The effects of the inflow turbulence on the fluid flow and heat transfer of a gas turbine passage flow have been investigated using wall...
Show moreThe effects of the inflow turbulence on the fluid flow and heat transfer of a gas turbine passage flow have been investigated using wall-resolved large eddy simulations. Numerical simulations are conducted in a linear vane cascade at different levels of inflow turbulence up to 12.4% at nominal exit chord Reynolds number of 500,000. At this Reynolds number and without any inflow turbulence, the boundary layer remains laminar on both sides of the vane. The presence of the velocity disturbances at the inlet augments the heat transfer on the leading edge and pressure side, triggers transition to turbulence over the suction side and alters the structure of the secondary flow in the turbine passage.The detailed analysis of the flow field indicates formation of large scale leading edge structures that wrap around the large leading edge and extend into both suction and pressure sides of the vane. These structures disturb the boundary layer and form streaky structures which augment the heat transfer on the pressure side. The perturbed boundary layer on the suction side eventually breaks up to turbulence due to the inner mode secondary instability which was reported earlier in a handful of studies.The vane and endwall heat transfer in regions affected by the secondary flows in the turbine passage are also studied in detail. A new representation on the origin and evolution of the passage vortex is presented. The passage vortex in the current geometry is originated from the pressure side passage circulation and not the pressure leg of the horseshoe vortex at the leading edge. Furthermore, it is observed that the distribution of the heat transfer coefficient on the endwall is significantly altered by the change in the level of the freestream turbulence and the approach boundary layer thickness. Finally, the effect of the freestream turbulence on the effectiveness of a slot cooling system in a symmetrical airfoil is studied. The large eddy simulations are conducted for a Reynolds number of 250,000 (based on the approach velocity and the leading edge diameter) and freestream turbulence levels of up to 13.7%. Current predictions capture the decay of the film cooling effectiveness at higher turbulence levels due to the higher mixing of the incoming hot gases and the coolant. It is been shown that the presence of arrays of pin fins in the preconditioning section of the slot cooling system plays a major role in the near field film cooling effectiveness and surface temperature distribution.
Show less

Title: WHY AND WHY-NOT PROVENANCE FOR QUERIES WITH NEGATION
Creator: Lee, Seokki
Date: 2020
Description: Explaining why an answer is in the result of a query or why it is missing from the result is important for many applications including...
Show moreExplaining why an answer is in the result of a query or why it is missing from the result is important for many applications including auditing, debugging data and queries, hypothetical reasoning about data, and data exploration. Both types of questions, i.e., why and why-not provenance, have been studied extensively, but mostly in isolation. A recent study shows that unification of why and why-not provenance can be achieved by developing a provenance model for queries with negation. In many complex queries, negation is natural and yields more expressive power. Thus, supporting both types of provenance and negation together can be useful for, e.g., debugging (missing) data over complex queries with negation. However, why-not provenance and — to a lesser degree — why provenance, can be very large resulting in severe scalability and usability challenges.In this thesis, we introduce a framework that unifies why and why-not provenance. We develop a graph-based provenance model that is powerful enough to encode the evaluation of queries with negation (First-Order queries). We demonstrate that our model generalizes a wide range of provenance models from the literature. Using our model, we present the first practical approach that efficiently generates explanations, i.e., parts of the provenance that are relevant to the query outputs of interest. Furthermore, we present a novel approximate summarization technique to address the scalability and usability challenges. Our technique efficiently computes pattern-based provenance summaries that balance informativeness, conciseness, and completeness. To achieve scalability, we integrate sampling techniques into provenance capture and summarization. We implement these techniques in our PUG (Provenance Unification through Graphs) system which runs on top of a relational database. We demonstrate through extensive experiments that our approach scales to large datasets and produces comprehensive and meaningful (summaries of) provenance.
Show less

Title: Foregrounding Temporality to Design with Emerging Futures
Creator: Heidaripour, Maryam
Date: 2020
Description: The rhetoric of today’s economy has framed entrepreneurship as a key contributor to inventing the future, which raises questions about who is...
Show moreThe rhetoric of today’s economy has framed entrepreneurship as a key contributor to inventing the future, which raises questions about who is counted as an insider, how the future is being designed, and for whom. The concentration of future-making has too long been in the hands of a few, given future’s tremendous impact on the many. This dissertation joins the growing body of scholarly explorations on channeling the design capacity to transition toward a future with a plural world system, where the economy offers a multiplicity of possibilities. Central to this exploration is to rethink how shaping futures might be done differently, with different people, and in different forms.By incorporating feminist temporality, I challenge the established mode of design investigation. My empirical chapters demonstrate the ways in which sharpening our temporal sensitivity could impact what we study, how we study it, and what we can find. In particular, I rearrange the power dynamics in design activities by opening up the position of knower to the emerging collectives. I then introduce the concept of designing a time-space yet to come that makes you wonder—an open invitation to rethink who we are and what we want to become.While it remains to be seen whether this contribution will have a meaningful impact on design knowledge, I argue that it makes a solid case for incorporating feminism in design. Feminist theory offers the theoretical underpinning for ontological reframing of design and helps us understand what other forms of design practice are emerging in this era of increasing complexity. I conclude with my take on an emerging design practice where the fundamental element of design is to enable other ways of knowing to inquire about what they truly want to become.
Show less

Title: Socially Responsible Investing and Style Investing
Creator: He, Di
Date: 2020
Description: This study focuses on two popular investment strategies. The first one is a combination of socially responsible investing and factor investing...
Show moreThis study focuses on two popular investment strategies. The first one is a combination of socially responsible investing and factor investing (SRIF), it is therefore a comparison between factor investing portfolios and their corresponding ESG screened factor investing portfolios, aiming at indicating whether there is an opportunity costs or benefits of being responsible in factor investing. Opportunity cost is regarded if the ESG screened factor investing portfolios have lower raw return, Sharpe ratio, and risk-adjusted return than their respective factor investing portfolios. In addition to simply comparison, I also build an empirical SRI strategy, achieving real outperformance of SRI. For the second strategy, investing in R&D intensity (high technology) stocks results in significant positive alpha over 40 years. However, the alphas decrease significantly after the “Tech Bubble”, because investors nowadays prefer those technology firms who can produce true profits. I provide empirical evidence to investor sentiment, proving both risk bearing and investor sentiment play important roles in the positive association between R&D-intensive and excess return.In the first SRIF strategy, five widely-accepted factors in academic: value, size, profit, investment, and momentum are used to construct original single factor investing portfolio as benchmarks, which can naturally solve the benchmark bias, factor bias in previous literature at some extent. In addition to fulfill empirical industry’s generalities and constraints, this study also covers multi-factor framework and constructs different long-short positions for investment processing. Following considerations of ESG measurement (ESG_net and ESG_Industry, the latter one for calibration of industry bias), sample period (whole period and sub period), portfolio weighting methods (equally weighted and capitalization weighted), and after excluding undiversified portfolio, there are total 192 comparisons between factor investing portfolios and ESG screened factor investing portfolios for each measures of performance. Results suggest that most investors (80% - 90%) have to bear non-statistically significant opportunity costs if they want to be socially responsible in factor investing. In addition, the opportunity costs in sub period (2004-2017) is remarkably less in scale than those in whole period (1992-2017), indicating an obvious “time effect” that investors will have less opportunity costs recently with more and more ESG information is disclosed. For empirical consideration of industry, I build a double sorting factor portfolio on profit and value, and its ESG screened portfolio outperform the single factor portfolio.For the second research, R&D expense is a key component of investment. There is long history literature claim that there is a positive relationship between R&D and stock returns. There are two main explanations of the positive association, which are mispricing and risk bearing. This study separates whole sample into two periods: before “Tech Bubble” and after “Tech Bubble”, indicating that the mispricing is weaker after “Tech Bubble” than that in before “Tech Bubble”, while risk bearing is persistent. In addition, this study finds that the excess returns are relatively high for those highly subjective and difficult to arbitrage technology securities, which are small stocks, high volatility stocks, unprofitable stocks, non-dividend-paying stocks before the “Tech Bubble”, but almost vanish after the “Tech Bubble”. Therefore, investor sentiment does exist. While for those true earning technology securities, their excess returns are persistent, indicating compensation of risk bearing.
Show less

Title: An experimental study on the effects of partial sleep deprivation on disordered-eating urges and behaviors
Creator: Johnson, Nicole Kathryn
Date: 2020
Description: Previous research has linked sleep disturbances with disordered eating. Studies have also shown that one night of partial sleep deprivation...
Show morePrevious research has linked sleep disturbances with disordered eating. Studies have also shown that one night of partial sleep deprivation causes increases in food intake and appetite disturbances. However, the effects of sleep deprivation on disordered eating are unclear as research has yet to examine the effects of one night of partial sleep deprivation (≤ 4 hours of sleep) on disordered eating in a representative adult female sample. Adult, female participants (N=40) completed eligibility and baseline measures reporting medical conditions, eating disorder symptoms, sleep disturbances, depressed mood, and anxiety symptoms. Participants were randomized to either the sleep-deprived condition (~50% of their average sleep duration) or the habitual-sleep condition (~100% of their average sleep duration). The morning after the sleep condition, participants completed self-report appetite and disordered eating measures before and after consuming a test meal and later that evening. The following statistical analyses, adjusted for multiple comparisons (p<0.002), found no significant group differences: independent samples t-tests (outcome: pre-meal appetite, disordered eating, and test-meal consumption), multivariate analyses of variance (MANOVAs; outcome: pre- and post-meal area under the curve disordered eating and appetite), repeated measures ANOVAs (time X group; outcome: pre- and post-meal appetite and disordered eating), analyses of covariance (ANCOVAs; controlling for pre-meal ratings; outcome: disordered eating at follow-up), and chi-square tests (outcome: follow-up appetite and disordered eating). Despite finding no support for the effect of sleep deprivation on disordered eating, this study extends previous research as a novel study using the experimental manipulation of sleep deprivation to examine its effects on disordered eating.
Show less

Title: MEN, WOMEN, AND LEADERS: THE EFFECT OF GENDER-LEADER CATEGORY CONGRUENCE ON SUPERVISOR EVALUATIONS
Creator: Lauritsen, Matthew William
Date: 2020
Description: Researchers employing Schein’s (1973, 1975) paradigm, ubiquitously conclude that the greater conceptual distance between leaders and women...
Show moreResearchers employing Schein’s (1973, 1975) paradigm, ubiquitously conclude that the greater conceptual distance between leaders and women compared to leaders and men is problematic for women in leadership roles. Six hundred eighty participants were recruited from MTurk to rate men, women, and leaders on agency and communion. Using polynomial regression analysis, the category congruence hypothesis was tested using two theories as interpretive frameworks: implicit leadership theory (ILT) and role congruity theory (RCT). A strict congruence effect was not found for any of the models. The results generally supported ILT, supervisor evaluations were highest when perceived supervisor characteristics exceeded the respondents’ leader category expectations. The results did not support RCT’s hypothesis about the negative effects of incongruence of women and leader category. Supervisor evaluations were highest when respondents held traditional gender stereotypes, not when they were congruent with the leader prototype. However, a general incongruence effect was found between male communion stereotypes and leader communion stereotypes leading to lower evaluations for male supervisors. That is, for men supervisors, the highest ratings were associated with high communion ratings of both men and leader categories. The results of this study are further discussed in relation to gender-leader category congruence and leadership.
Show less

Title: HOW DO SECONDARY STUDENTS MAKE DECISIONS ON SOCIOSCIENTIFIC ISSUES: WHAT DO THEY CONSIDER IMPORTANT?
Creator: LePretre, Dawnne M
Date: 2019
Description: Linking science and action is the epitome of scientific literacy (Hurd, 1972; Kuhn, 1972; Watson, 1969). Before becoming acting citizens,...
Show moreLinking science and action is the epitome of scientific literacy (Hurd, 1972; Kuhn, 1972; Watson, 1969). Before becoming acting citizens, students need to balance subject matter knowledge, personal values, and societal norms in decision-making (DM) on Socioscientific Issues (SSI) (Aikenhead, 1985; Grace & Ratcliffe, 2002; Kolstø, 2001; Zeidler, 1984). Existing literature suggests a variety of models and strategies to guide how students should think about SSI topics versus beginning with what students are thinking concerning SSI! This study aimed to identify the DM factors students considered across a variety of SSI and to determine if DM factors were common across topics or specific to a SSI. Students in grades 10-12 participated from seven schools and ten regular science classrooms, primarily located in a large Midwest city (n=498). The sample was 50% female, 50% male, and roughly 33% of students from each grade level.Across 60 enacted lessons on six different SSI topics, multiple sources of data were collected, including student artifacts, audiotapes of class discussions/interviews, field notes, and teacher surveys. Students engaged in a minimum of three different SSI topical lessons, implemented over a period between one to nine weeks for an average instructional time of 115 minutes per topic. Decision-making differed across students in various groupings, indicating that secondary students used both general and specific factors when making decisions on SSI. Further, trends emerged, indicating various student groups' valued DM factors differently. On several topics, students of different gender, grade levels, ethnicities, and school type considered different DM factors to different levels of support. For example, on the topic of plastics and pollution, 10th grade, female, and Hispanic students tended to identify concern for animals and sea life as their most prominent DM factor. Another trend included larger class sizes tending to cite more DM factors on a topic than students in smaller sized classrooms engaged on the same topic. Overall, 15 common or shared DM factors emerged that students considered when making decisions across multiple SSI contexts. In addition, each specific SSI context had between one and 15 specific or exclusive DM factors cited directly by students in this study.
Show less

Title: DATA SHARING WITH PRIVACY AND SECURITY
Creator: Qian, Jianwei
Date: 2019
Description: Data is a non-exclusive resource and has synergistic effects. Open data sharing will enhance the utilization of big data’s value and...
Show moreData is a non-exclusive resource and has synergistic effects. Open data sharing will enhance the utilization of big data’s value and tremendously boost economic growth and transparency. Data sharing platforms have emerged worldwide, but with very limited services. Security is one of the main reasons why most data are not commonly shared. This dissertation aims to tackle several security issues in building a trustworthy data sharing ecosystem. First, I reveal the privacy risks in data sharing by designing de-anonymization and privacy inference attacks. Second, I present an analysis of the relationship between the attacker's knowledge and the privacy risk of data sharing, and try quantifying and estimating the risk. Then, I propose anonymization algorithms to protect the privacy of participants in data sharing. Finally, I survey the status quo, privacy and security concerns, and opportunities in data trading. This dissertation involves various data types with a focus on graph data and speech data; it also involves various forms of data sharing including collection, publishing, query, and trading.
Show less

Title: Sustainable Solutions in Complex Spaces of Innovation
Creator: Nogueira, André Martins
Date: 2019
Description: Even though the interconnectivity between human activities and the integrity of ecological systems has long been recognized, the development...
Show moreEven though the interconnectivity between human activities and the integrity of ecological systems has long been recognized, the development of design practices that account for such interconnectivity can be considered relatively new. As such, contemporary institutions and their arrangements were not designed accordingly to their potential to promote sustainable and equitable flows of different types of resources; they lack the capability and structure to operate in the speed and scale in which humans are dynamically interacting with themselves, and with the natural environment. As the world has passed the 7.5 billion mark, such a condition is generating unintended socio-ecological-technical consequences being empowered by the fast-changing technology industry. New lenses and models for understanding the connectivity of social, ecological and technical systems underlying contemporary institutional arrangements are required to advance expertise in redirecting the flow of different types of resources for the sustainability of these systems. However, how humans perceive systems is largely framed by who is included in the discussion and the experiences and interests that they bring to bear. Even though there will always be a discrepancy between what is perceived, and the actual system at play, there are greater opportunities to expand such perception by drawing more deeply on systems thinking and the notion of resources. This dissertation advances design knowledge in the pursuit of bridging the gap between theoretical discourses and the pragmatism necessary to intervene socio-ecological-technical dynamics by exploring how designers might embed principles of sustainability into choice-making processes for innovation, and it proposes a new approach through which designers can advance their practices in enabling more sustainable flows of resources.
Show less

Title: Nanopore Detection of Heavy Metal Ions
Creator: MohammadiRoozbahani, Golbarg
Date: 2019
Description: Nanopore sensing is an emerging analytical technique for measuring single molecules. Under an applied potential bias, analyte molecules are...
Show moreNanopore sensing is an emerging analytical technique for measuring single molecules. Under an applied potential bias, analyte molecules are transported through the nanopore and cause ionic current modulations. Accordingly, the fingerprint of the analyte is reflected in the signature of the current blockage events. Due to its advantages such as lable-free and multi-analyte detection, nanopore sensing technology has been utilized as an attractive versatile tool to study a variety of topics, including biosensing of different species, such as DNA, RNA, proteins, peptides, anions, and metal ions.Metal ions play a crucial role in human health and environmental safety. Although metal ions are essential for numerous biological processes, the presence of the wrong metal, or even the essential metals in the wrong concentration or location, can lead to undesirable results and serious health concerns, including antibiotic resistance, metabolic disorders, mental retardation, and even cancer. Therefore, it is still of prime importance to develop highly sensitive and selective sensors for metal ions.In this dissertation, various nanopore sensing strategies to detect metal ions will first be discussed. These include: a) construction of metal ion binding sites in the nanopore inner surface; b) utilization of a biomolecule as a ligand probe; and c) employing enzymatic reactions. Then, three projects will be summarized. Among them, two projects are involved with detection of non-essential metal ions: uranyl and thorium ions, while the other is targeted at essential element, zinc ion. To be more specific, uranyl and thorium ions are detected by taking advantage of peptide molecules as ligand probes. In this case, the event signatures of peptide molecules in the nanopore are significantly different in the absence and presence of metal ions, which might be attributed to the conformational change of the biomolecules induced by the metal ion-biomolecule interaction. On the other hand, zinc ion is detected based on enzymatic reaction: without Zn2+, ADAM17 (a zinc dependent protease) is inactive and cannot cleave peptide substrate molecules; in contrast, with Zn2+ ion in the solution, the enzyme was activated, and its cleavage of the peptide substrate produced new types of blockage events with smaller residence time and amplitude values than those the peptide substrate.
Show less

Title: Regenerating the Jordan River: Through Ecological and Sociocultural Interventions
Creator: Shadid, Rula
Date: 2019
Description: The Jordan River is often described as one of the world’s most unique eco-systems and is attributed to serving as a cradle of history, culture...
Show moreThe Jordan River is often described as one of the world’s most unique eco-systems and is attributed to serving as a cradle of history, culture, and spirituality in the ancient and modern times. Archaeological evidence on its banks reveal signs of some of the world’s earliest existences of civilization. Its history as a meeting place for the crossing and exchange between plants, animals, and human societies, along with its strong association to three of the world’s great religions – Christianity, Islam, and Judaism – has made it a world known and important site. Being located in the Middle East, in the heart of a complex political conflict that has been ongoing since the middle of the last century, years of war, political clashes, and water and resource exploitation has reduced the river from a once lush and bio-diverse ecosystem to nothing but a polluted stream. Today the river is a “hydro-border” that divides the competing nations around it and segregates the people of the Jordan Valley in which the river runs via militarized security efforts. The conflict has left the region politically and socially segregated and has eliminated the productive exchange which once allowed the valley to thrive while efforts to protect, preserve, or rehabilitate the river are given little chance to succeed. The thesis addresses river degradation and social segregation as two interdependent issues in the Jordan Valley. It highlights saving the Jordan River as a driver for integration between the conflicting society and points to the Jordan Valley river border as a site for regenerative interventions that suggest an alternative and productive way of life in an area filled with conflict, economic distress, and spatial divide through the collaboration and exchange of efforts, ideas, and resources.
Show less

Title: STAKEHOLDER FEEDBACK ON A NOVEL EMOTION REGULATION INTERVENTION FOR PRESCHOOL-AGE CHILDREN WITH DISRUPTIVE BEHAVIOR PROBLEMS: A THEMATIC ANALYSIS
Creator: Lossia, Amanda
Date: 2019
Description: Disruptive behavior disorders are among the most prevalent psychological disorders in preschoolers. There are evidence-based treatments for...
Show moreDisruptive behavior disorders are among the most prevalent psychological disorders in preschoolers. There are evidence-based treatments for these disorders, but clinically significant behavior problems persist in approximately one-fourth to one-third of children after treatment. These treatments consist of behavioral parenting interventions and are not designed to directly address children’s affective dysregulation, which is a core component of behavior problems. To address this limitation, a manualized intervention was developed to treat disruptive behavior in preschool-age children by specifically targeting their emotion regulation abilities as the mechanism of change by coaching the caregiver to scaffold the child’s emotion regulation strategy use. The purpose of the present study was to further the development of this intervention by obtaining feedback from key stakeholders (i.e., caregivers and therapists) on the intervention’s focus, content, and procedures. Obtaining this feedback is an essential component of developing a novel psychosocial intervention. A qualitative thematic analysis of in-depth focus group discussions was conducted. Data were organized into the following broad themes: Intervention approach (support for targeting emotion regulation but ensuring the approach is an appropriate fit and considering the important role of behavioral strategies; additional focus on facilitating a positive caregiver-child relationship; developing some independent regulation skills in the child), Intervention structure and session content (making the intervention structure more flexible or modular; retaining the main intervention components with modifications to enhance acceptability, relevance, and developmental appropriateness), The caregiver’s role (the caregiver’s role is of primary importance and should be active throughout all sessions; ensuring adequate caregiver preparation and skill development; additional primary focus on facilitating the caregiver’s own emotion regulation; attention to the caregiver’s own therapeutic needs), Individualized approach (individualizing the content and timing of all sessions to account for individual needs), Generalizability (ensuring generalization of skills to home and other settings through effective at-home practice and including other primary caregivers and family members in sessions), and Learning and skill development (considering individual differences in how children and caregivers learn and modifying activities accordingly). These themes and stakeholders’ specific feedback will guide revisions to the intervention manual prior to pilot testing and further examination of efficacy and effectiveness.
Show less

Title: The Role of Ethnic Similarity, Perceived Communication Style Deviation, and Cultural Intelligence in Leader-Member Exchange and Trust
Creator: Polyashuk, Yelena
Date: 2019
Description: This study examined those factors that contribute to a better working relationship between a leader and a subordinate or make that working...
Show moreThis study examined those factors that contribute to a better working relationship between a leader and a subordinate or make that working relationship challenging. Specifically, we investigated the effect of ethnic configuration within the leader-subordinate dyad and perceived dissimilarity on Leader-Member Exchange (LMX) and trust. Communication style deviation was tested as a mediator between actual, as well as perceived dissimilarity and relational outcomes. Cultural Intelligence (CQ) was included as a moderator, the presence of which could ameliorate the negative impact of dissimilarity on LMX and trust. In order to test these predictions, a survey was administered to 614 participants. Participants were working students at an urban, Midwestern, public university. Results showed that in presence of low CQ among respondents, there was a negative impact of ethnic dissimilarity on LMX. However, no impact of ethnic similarity/dissimilarity on trust was found. Specific dyad composition of the leader-subordinate dyad had no significant impact on LMX or trust. Finally, communication style deviation partially mediated the relationship between perceived dissimilarity and the two outcome variables of LMX and trust. These findings revealed that in order to build a high-quality relationship within an ethnically diverse leader-subordinate dyad, both CQ and alignment in communication style are of consequence.
Show less

Title: Fast Automatic Bayesian Cubature Using Matching Kernels and Designs
Creator: Rathinavel, Jagadeeswaran
Date: 2019
Description: Automatic cubatures approximate multidimensional integrals to user-specified error tolerances. In many real-world integration problems, the...
Show moreAutomatic cubatures approximate multidimensional integrals to user-specified error tolerances. In many real-world integration problems, the analytical solution is either unavailable or difficult to compute. To overcome this, one can use numerical algorithms that approximately estimate the value of the integral. For high dimensional integrals, quasi-Monte Carlo (QMC) methods are very popular. QMC methods are equal-weight quadrature rules where the quadrature points are chosen deterministically, unlike Monte Carlo (MC) methods where the points are chosen randomly.The families of integration lattice nodes and digital nets are the most popular quadrature points used. These methods consider the integrand to be a deterministic function. An alternative approach, called Bayesian cubature, postulates the integrand to be an instance of a Gaussian stochastic process. For high dimensional problems, it is difficult to adaptively change the sampling pattern. But one can automatically determine the sample size, $n$, given a fixed and reasonable sampling pattern. We take this approach using a Bayesian perspective. We assume a Gaussian process parameterized by a constant mean and a covariance function defined by a scale parameter and a function specifying how the integrand values at two different points in the domain are related. These parameters are estimated from integrand values or are given non-informative priors. This leads to a credible interval for the integral. The sample size, $n$, is chosen to make the credible interval for the Bayesian posterior error no greater than the desired error tolerance. However, the process just outlined typically requires vector-matrix operations with a computational cost of $O(n^3)$. Our innovation is to pair low discrepancy nodes with matching kernels, which lowers the computational cost to $O(n \log n)$. We begin the thesis by introducing the Bayesian approach to calculate the posterior cubature error and define our automatic Bayesian cubature. Although much of this material is known, it is used to develop the necessary foundations. Some of the major contributions of this thesis include the following: 1) The fast Bayesian transform is introduced. This generalizes the techniques that speedup Bayesian cubature when the kernel matches low discrepancy nodes. 2) The fast Bayesian transform approach is demonstrated using two methods: a) rank-1 lattice sequences and shift-invariant kernels, and b) Sobol' sequences and Walsh kernels. These two methods are implemented as fast automatic Bayesian cubature algorithms in the Guaranteed Automatic Integration Library (GAIL). 3) We develop additional numerical implementation techniques: a) rewriting the covariance kernel to avoid cancellation error, b) gradient descent for hyperparameter search, and c) non-integer kernel order selection.The thesis concludes by applying our fast automatic Bayesian cubature algorithms to three sample integration problems. We show that our algorithms are faster than the basic Bayesian cubature and that they provide answers within the error tolerance in most cases. The Bayesian cubatures that we develop are guaranteed for integrands belonging to a cone of functions that reside in the middle of the sample space. The concept of a cone of functions is also explained briefly.
Show less

repository.iit

Search the repository

Pages

Pages

Refine Results

Type

Date

Academic status of creator

Department

Subject

Creator

Rights