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Title: FALL DETECTION USING WIRELESS BODY SENSOR NETWORK
Creator: Sarkar, Oishee
Date: 2015, 2015-05
Description: The aim of this project is to develop a stand-alone wearable body sensor network with the primary aim of fall detection of human bodies. This...
Show moreThe aim of this project is to develop a stand-alone wearable body sensor network with the primary aim of fall detection of human bodies. This network should be able to detect a fall remotely and in real time, and send an intimation along with the relevant medical details to an emergency contact and/or the nearest hospital. Several methods of fall detection have been discussed in this report and the advantages and disadvantages of them are analyzed. An optimal fall detecting mech- anism has been chosen to perform the function. Physical sensors have been used for detection of the fall, namely accelerometers and gyroscopes. Data has been collected from these sensor, and a central processing node has been utilized to process the incoming data to determine whether a fall has taken place as well as detecting the position and orientation of the body that the sensors are strapped on to. A Rasp- berry Pi processor acts as the central node. The threshold technique is employed to determine if the body has fallen over, and in what orientation it lands. The smart phone is used as a communication node and the result from the processor is obtained in a form that can be sent to the smart phone via bluetooth for further operation.
M.S. in Electrical Engineering, May 2015
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Title: EFFECTS OF ENGINEERING USING BACTERIAL HEMOGLOBIN ON THE ABILITY OF ETHANOLOGENIC E. COLI TO FERMENT LIGNOCELLULOSIC HYRDOLYSATE TO ETHANOL
Creator: Kunkel, Stephanie
Date: 2011-05-03, 2011-05
Description: E. coli strain FBR5, which has been engineered to direct fermentation of sugars to ethanol has been further engineered in our laboratory using...
Show moreE. coli strain FBR5, which has been engineered to direct fermentation of sugars to ethanol has been further engineered in our laboratory using three different constructs, to contain and express the Vitreoscilla hemoglobin gene (vgb). The resulting strain (TS3) expresses VHb at a moderate level under microaerobic conditions in shake flasks and produces more ethanol than the parental strain (FBR5) with glucose, xylose, or corn stover hydrolysate as the carbon source. In the work reported here, this research was extended, focusing particularly on fermentation of lignocellulosic hydrolysate. The increased ability of the VHb-bearing strain to produce ethanol from pure glucose or xylose was confirmed. A VHb-correlated increase in ethanol production was also noted for lignocellulosic hydrolysate produced in our laboratory, but not for ligncellulosic hydrolysate prepared by the National Laboratory for Renewable Energy (NREL). Experiments were performed at several hydrolysate levels for both prepartories, in an attempt to determine the cause of the difference. One possibility is differences in levels of toxic hydrolysis byproducts in the two preparations as well as increased sensitivity to these toxins due to VHb expression.
M.S. in Biology, May 2011
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Title: PHOTOCATHODE TUNABILITY: THE PHOTOEMISSIVE PROPERTIES OF ULTRA-THIN MULTILAYERED MgO/Ag/MgO FILMS SYNTHESIZED BY PULSED LASER DEPOSITION
Creator: Velazquez, Daniel Gomez
Date: 2015, 2015-05
Description: Much of the early development of photocathode materials was aimed at the growth of photoemissive thin films with low work function, and high...
Show moreMuch of the early development of photocathode materials was aimed at the growth of photoemissive thin films with low work function, and high quantum efficiency (QE). It has been shown, both theoretically and experimentally, that metal-insulator junctions can lead to the modification of the work function and QE for coverages of a few monolayers of metal oxides on metallic substrates. However, the production of electron beams suitable for new photoinjector technologies in many instances requires low emittance beams from the cathode itself. Often the cathode intrinsic emittance plays an important role in new e-gun designs. A demonstration of the ability to control photoemissive properties by engineering the band structure of a photocathode could provide a pathway to meet the demands of new photoinjector technologies. Nemeth et al. [Phys. Rev. Lett. 104, 046801 (2010)] used density functional theory (DFT) to model the properties of a multilayered structure of MgO/Ag(001)/MgO with 4 monolayers of Ag(001) flanked by n monolayers (ML) of MgO. Their model indicated that it is possible to reduce the emittance of a photoemitted electron beam when the thickness n of the MgO layers is 2 or 3 monolayers because the surface band structure exhibits a narrowing of the density of occupied states in momentum near the Γ-point neighboring the Fermi Level. The theoretical prediction concerning the emission properties of these multilayers structures was tested by fabricating them, and then characterizing their emission properties. Synthesis of multilayered MgO/Ag/MgO films was performed using a custom-built pulsed laser deposition (PLD) system. In-situ growth monitoring was carried out by Reflection High-Energy Electron Diffraction (RHEED). Ex-situ techniques such as Scanning Tunneling Microscopy (STM), Scanning Electron Microscopy/Energy Dispersive Spectroscopy (EDS) and Photoelectron Spectroscopy (PES) were used to show the formation of the crystalline and chemical structure of the multilayered films. A Kelvin Probe/photocurrent-detector system, custom-built for this research, was used to measure the work function and QE of the samples. Angle Resolved Photoelectron Spectroscopy was used to measure the angular photoelectron yield. Simultaneous reduction of work function and increase of QE was observed for (001) oriented multilayers of various thicknesses with respect to that of a bare Ag/MgO(001) surface. Work function measurements of multilayers of various thicknesses in the (111) orientation also registered a monotonic reduction with respect to that of a bare Ag/Si(111) surface. Angular emission was compared for a MgO/Ag/MgO multilayer (thicknesses of 3 ML/4 ML/3 ML) sample and Ag/MgO(001). Emission analysis of the angle-resolved photoelectron spectra shows a net change in the angular emission with high kinetic energy electron density shifted toward surface-normal emission. Experimental results were consistent with theoretical predictions, which open the promising possibility of customizing emission properties by direct manipulation of the surface band structure of the emitter.
Ph.D. in Physics, May 2015
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Title: INVESTIGATING MINDFULNESS AS A MODERATOR OF THE CONGRUENCE BETWEEN EXPLICIT AND IMPLICIT ATTITUDES OF HETEROSEXUAL MEN REGARDING HETEROSEXUALITY, HOMOSEXUALITY, AND BISEXUALITY
Creator: Unis, Barry J.
Date: 2014, 2014-12
Description: Althou gh some researchers have used implicit measures to investigate sexual orientation attitudes, very few have used the Implicit Relational...
Show moreAlthou gh some researchers have used implicit measures to investigate sexual orientation attitudes, very few have used the Implicit Relational Assessment Procedure (IRAP) , which has been shown to be very difficult for participants to provide fake results . This study investigated self-identified heterosexual male college students' explicit and implicit attitudes regarding the acceptability of heterosexual, homosexual, and bisexual people. Explicit measures includ ed the Modem Homonegativity Scale, Attitudes Regardin g Bisexuality Scale, Homonegati vity Scale, and the Collective Self-Esteem Scale. The impli cit measure was the IRAP. A one-way analysis of variance (ANOVA) revealed no statistically significant differences among explicit attitud es or implicit attitudes. Acceptability rankings based on the explicit measures were, from most to least, hetero sexual person, bisexual woman, bisexual man, lesbian, and gay man. In contrast, acceptability rankings based on the IRAP were heterosexual man, heterosexu al woman, gay man, bisexual man, bisexual woman, and lesbian. Mindfulness, measured using the Five-Facet Mindfulness Questionnaire, was investigated as a moderator between explicit and implicit attitudes. The moderation analysis was not statistically significant; however, mindfulness was related to attitudes toward bisexual people. Specifically, describin g thoughts and feelings was negati vely associated with negati ve attitudes toward bisexual people. This study adds to the literature by expanding the young research areas of bisexuality, implicit attitude s, and mindfulness, specifically the relationship between describing and attitudes toward bisexual people.
M.S. in Psychology, December 2014
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Title: SOCIAL SKILLS AND ACADEMIC ACHIEVEMENT: DIFFERENCES BETWEEN AFRICAN AMERICAN, CAUCASIAN, AND LATINO STUDENTS
Creator: Filerman, Stacey
Date: 2011-08, 2011-07
Description: Previous studies have demonstrated a significant relationship between social skills and academic achievement (McClelland, Morrison, & Holmes,...
Show morePrevious studies have demonstrated a significant relationship between social skills and academic achievement (McClelland, Morrison, & Holmes, 2000; Payton et al., 2008; Wentzel 1993). This relationship may be due to Vygotsky‟s and Bandura‟s social learning theories, in which learning occurs through observation, imitation, and interaction with one‟s environment (Bandura, 1997; Vygotsky, 1978). Large differences in academic achievement among minority and non-minority students in the United States have been documented for over three decades (Coleman, 1968; National Center, 1978- 1998). Current research examining differences in social skills and academic achievement by race/ethnicity is limited in that dichotomous comparisons have been made between Caucasian and African American, or minority students (Malecki & Elliot, 2002). Social skills measures have also been questioned for their construct validity among minorities (Van Horn, Atkins-Burnett, Karlin, Landesman Ramey, & Snyder, 2007). The current study attempts to expand the understanding of the relationship between social skills and academic achievement in African American, Caucasian, and Latino third, fourth, and fifth grade students. In particular, this study examined teacherand self-rated social skills, reading and mathematics achievement, English proficiency, an estimate of intelligence, and socio-economic status. The results of the current study revealed significant differences in teacher-rated social skills by Race/Ethnicity and no differences in self-ratings. Significant group differences were found also found in reading and not math. Regression analyses revealed teacher-rated social skills did not mediate the relationship between race/ethnicity and academic achievement.
Ph.D. in Psychology, July 2011
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Title: EXAMINING GROUP DIFFERENCES IN EXECUTIVE FUNCTIONS IN CHILDREN WITH MTBI AND ADHD
Creator: Bodzy, Mary Elizabeth
Date: 2011-05, 2011-07
Description: Executive Functions (EF) are described as behaviors associated with the frontal cortex of the brain that are responsible for higher order...
Show moreExecutive Functions (EF) are described as behaviors associated with the frontal cortex of the brain that are responsible for higher order thinking (Kolb & Whishaw, 1996), and aid in goal directed behavior (Gioia, Isquith, & Guy, 2001). Traumatic brain injury (TBI) and Attention Deficit Hyperactivity Disorder (ADHD) are two conditions that render the frontal systems vulnerable to dysfunction (Fletcher, et al., 1990; Singer & Walkup, 1991). Previous literature found EF deficits in children with ADHD (Barkley, 1997; Barkley, Edwards et al., 2007; Brocki, & Bohlin, 2006; Nigg et al., 2002; Solanto et al., 2001), and children with a TBI (Anderson et al., 2005; Catroppa, & Anderson, 2005; Catroppa et al., 2007; Mangeot et al., 2002; Nolin, 2006; Dennis et al., 1996; Ponsford et al., 1999; Yeates et al., 1999). The current study sought to examine the relationship between a performancebased measure and parent-report measure of EF domains, including working memory, inhibition/impulse control, attention, and processing speed. This study also explored group differences in EF domains between children with ADHD and mild TBI (mTBI), compared to controls in a sample of 180 participants 5-18 years old. Measures included a performance-based measure of EF (ImPACT) and parent-rated measure of executive functioning (BRIEF). Results indicated that parent-report and performance-based measures of executive functioning are related on some tasks (inhibition, emotional control, and monitoring were related to visual and working memory, and processing speed) and unrelated on others (organization, planning, and shifting unrelated to visual and working memory, processing speed, and impulse control). Females performed better than males on performance-based viii inhibition and working memory tasks and on parent-reported monitoring of behavior. After controlling for gender, effects for age, group, and age x group interaction were found on performance-based and parent-report of EF functioning. Specifically, effects for age (5-8, 9-12. 13-18) indicated differences between children of different ages on performance-based working memory and processing speed, and parent-reported working memory, inhibition, emotional control, and monitoring. Effects for group indicated differences between groups (ADHD, mTBI, controls) on performance-based working memory, and impulse control/inhibition, and parent-reported working memory, inhibition, initiation, planning/organization, organization of materials, and monitoring. The effect of the age x group interaction indicated differences on performance-based impulse control/inhibition and processing speed, and parent-reported working memory. In summary, the results of this study suggest there are developmental differences in executive functioning domains.
Ph.D. in Clinical Psychology, July 2011
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Title: NEW BEAMFORMING AND SPACE-TIME CODING SCHEMES FOR MIMO WIRELESS SYSTEMS
Creator: Tavassoli, Farhad
Date: 2013, 2013-05
Description: Space-time coding and Beamforming are two main techniques utilized in multiple-input multiple-output (MIMO) wireless systems to increase...
Show moreSpace-time coding and Beamforming are two main techniques utilized in multiple-input multiple-output (MIMO) wireless systems to increase channel capacity. In this work, we present new beamforming algorithms and space-time codes for MIMO wireless systems to reduce the complexity and enhance the performance. We present a new framework to obtain beamforming algorithms for code division multiple access (CDMA) and orthogonal frequency division multiplexing (OFDM) systems based on principal component analysis (PCA) approach. Four different PCA objective functions are used as examples to illustrate how to obtain new beamforming algorithms based on the proposed framework. Since two of the objective functions result in the same algorithm, three different beamforming algorithms are obtained for CDMA and OFDM systems. We show that the new algorithms offer a desirable performance while they have considerably lower computational complexity than the optimum algorithms. It is demonstrated that the proposed algorithms also have a fast convergence rate. We also propose new space-time codes for both coherent and non-coherent wireless systems which can provide lower symbol error rates than existing codes in the same class. For the coherent case, we propose a new quasi-orthogonal code to provide a full-rate full-diversity transmission. Unlike the other codes in the literature, the proposed code does not require the transmitted symbols to be chosen from two different constellations. Choosing all symbols from only one constellation reduces the required storage memory to half of that needed in other methods. It also avoids decreasing the minimum distance between the symbols and hence, avoids degrading the coding gain. For the non-coherent case, a new constellation design for differential unitary space-time modulation is proposed. We generate xi a set of unitary matrices from the multiplication of a simple unitary matrix with entries of 1 by diagonal matrices made from quaternary alphabets. Then, the proposed constellation is formed from the product of the optimum matrix chosen from this set and the optimized diagonal matrix first used for the cyclic codes. We show that the proposed constellation yields a larger diversity product as well as a lower union bound for pairwise error probability with the same or lower complexity compared to other existing constellations.
PH.D in Electrical Engineering, May 2013
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Title: ESSAYS ON DISTRIBUTIONALLY ROBUST PORTFOLIO OPTIMIZATION
Creator: Ousawat, Thitapon
Date: 2013, 2013-07
Description: Interest in distributionally robust optimization has been increasing recently. In this dissertation, we review recent developments in the...
Show moreInterest in distributionally robust optimization has been increasing recently. In this dissertation, we review recent developments in the literature in this eld and propose a model for distributionally robust mean-risk portfolio optimization. The model optimizes a risk-averse objective function with the worst-case return as reward and worse-case conditional Value-at-Risk as the risk measure. The model considers ambiguity in the distribution of data used to estimate the asset returns in the optimization model by creating an ambiguity set using -divergence measures which measure the distance between vectors. A numerical example is shown using the Kullback-Leibler divergence measure as the -divergence measure. A model for distributionally robust portfolio optimization with transaction costs is used to compare the performance of a distributionally robust mean-CVaR portfolio with the nominal as well as equally-weighted portfolio. The result shows that, under certain conditions, the distributionally robust model performs better than both the nominal and equally-weighted portfolio.
PH.D in Management Science, July 2013
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Title: INVESTIGATION OF POSSIBLE DYNAMIC INTERACTION OF DFIGS OF DIFFERENT CAPACITY EXISTING IN THE SAME WIND FARM
Creator: He, Fan
Date: 2011-12, 2011-12
Description: This paper explores the possibility of dynamic interaction between DFIGs of different capacity in a grid connected and islanding mode wind...
Show moreThis paper explores the possibility of dynamic interaction between DFIGs of different capacity in a grid connected and islanding mode wind farm. The modeling of DFIG is presented in the paper. The case of adding 5 MW DFIGs to a wind farm with existing 1.5 MW DFIGs is considered. Grid-connected scenario is considered regarding the connection of the units. Moreover, step-up wind speed, noisy wind speed and fault at infinite bus will be introduced as disturbances to examine the possible dynamic interaction. Simulation using MATLAB and Simulink has been used to investigate all cases. To further justify the simulation results, a series of modal small perturbation analysis is also conducted.
M.S. in Electrical Engineering, December 2011
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Title: VITREOSCILLA HEMOGLOBIN AS A STRATEGY TO ENHANCE BIODESULFURIZATION IN RHODOCOCCUS IGTS8
Creator: Bai, Nan
Date: 2014, 2014-05
Description: The bacterium Rhodococcus sp. IGTS8 contains the dsz operon encoding enzymes for the 4S pathway, which enables it to use dibenzothiophene (DBT...
Show moreThe bacterium Rhodococcus sp. IGTS8 contains the dsz operon encoding enzymes for the 4S pathway, which enables it to use dibenzothiophene (DBT), an organic sulfur containing molecule found in petroleum, as the sole source of sulfur for its metabolism. The gene vgb from Vitreoscilla encoding hemoglobin (VHb) has been widely studied and is used for improving the usefulness of a large number of heterologous hosts, like prokaryotes, lower eukaryotes and even higher plants. We produced the engineered strain IGTS8[pRESX-vgb] in which vgb was introduced into Rhodococcus sp. IGTS8. We measured the growth and the ability of desulfurization of DBT for this transformed strain (compared to the untransformed host) under both high and low aeration conditions. From CO-difference spectra, we found that VHb was successfully expressed in this transformant and the expression level was similar to that in certain other heterologous hosts. The transformant had much greater growth than untransformed IGTS8, cultured under both high and low aeration in CDM with DBT as the only sulfur source (the transformed strain outgrew the untransformed strain by about 380 % under high aeration and 68 % under low aeration). Unfortunately, we found that the color of the product from reaction of the Gibbs reagent with the final metabolite of DBT produced by the transformant was not blue. This did not allow us to directly compare the desulfurization abilities of the transformant and the untransformed strain. We did another experiment to prove that IGTS8[pRESX-vgb] still used DBT as its sole source of sulfur by culturing this transformant in CDM without DBT. IGTS8[pRESX-vgb] cannot grow in CDM without DBT. One possible explanation for this result is that the final product of the 4S pathway in the transformant may be converted to a form other ix than 2-HBP. In any case, the much better growth of the transformant compared to that of the untransformed strain provides indirect evidence that VHb does enhance biodesulfurization.
M.S. in Biology, May 2014
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Title: SURVIVAL AND SANITIZER RESISTANCE OF SALMONELLA ENTERICA ENTERITIDIS ON SHELL EGGS
Creator: Vogan, Jill Ann
Date: 2011-05-01, 2011-05
Description: The Gram negative bacterium Salmonella sp. is the most common cause of gastroenteritis in the United States and abroad. Its life cycle...
Show moreThe Gram negative bacterium Salmonella sp. is the most common cause of gastroenteritis in the United States and abroad. Its life cycle persists when the bacteria is picked up from the environment and ingested by a host animal. The bacteria adhere to the host’s small intestine and penetrate into the sub-epithelial tissue where it causes diarrhea and vomiting. The bacteria redeposit into the environment via the aforementioned route; thus, repeating the cycle. Salmonella can infect a variety of hosts and different serotypes vary in severity. In addition to the disease causing infections of some host animals such as birds and reptiles provide a reservoir for Salmonella. Reservoir hosts can carry and transmit the bacterium without showing any signs or symptoms of infection. The avian host can pick up the bacteria, by ingestion of contaminated food and water, and deposit it onto the surface or inside the egg. Salmonellosis is then transmitted to human by consumption of contaminated eggs. Salmonella enterica serotype Enteritidis is the most common serotype associated with contaminated chicken eggs. Salmonella Enteritidis inoculated onto the surface of whole chicken eggs was able to survive for at least two hours post inoculation. The rate of cell death on the shell surface increased steadily for the first 40 minutes of drying and tapered through the two hour end point. The death rate increase may have correlated with drying time on the shell surface. Further, the bacteria were able to attach to the shell within 10 minutes of incubation. Morphological examination of cells surviving on egg shells showed collapsing of the surface when dried for 30 minutes. When allowed to dry on the egg shell surface for two hours, Salmonella was able to survive sanitization with either 200 ppm hypochlorite or quaternary ammonium based sanitizer. Interestingly, a more vigorous recovery method was required to remove bacterial cells surviving on the shell surface post sanitization indicating that the sanitizers caused increased attachment.
M.S. in Biology, May 2011
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Title: Capital Design: The Role of Design in Institutional Capital Allocation
Creator: Ostapchuk, Jordan
Date: 2024
Description: There is a paradox within the $100 trillion institutional investment industry: the more choices an institutional investor has, the more...
Show moreThere is a paradox within the $100 trillion institutional investment industry: the more choices an institutional investor has, the more challenging it becomes to make investment decisions. This paradox is significant because capital is one of the most transformational elements of the 21st century, driven by financialization, universal ownership, and increasing systemic risks. The direction of capital flows significantly influences the approach to addressing climate change, aging populations, and the transition to sustainable energy, in addition to supporting the essential physical and social infrastructure supported by institutional capital. This research proposes and substantiates a novel hypothesis: design can significantly influence capital allocation in institutional investment contexts. Through an institutional case study, expert interviews, workshops with master’s level design students, and systems-informed reflective practice, this research identifies asset classes as an important and changeable lens through which institutions engage with the future. It explores how these asset classes shape choices in the capital allocation process and identifies eight design capabilities particularly suited for institutional investment contexts. In doing so, it introduces a framework termed Capital Design. This framework illustrates how design can influence institutional capital allocation by integrating these design capabilities with investment tools through informational lenses within a choice/knowledge map. As a result, Capital Design offers an innovative approach for investors and investees to reorient toward emergent asset categories that directly meet the most urgent societal needs.
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Title: Evaluation of the Native Microbiota and Comparative Analysis of a Known Cronobacter Sakazakii and a Newly Isolated Bacillus Cereus Strain in Powdered Infant Formula
Creator: Patil, Sonali Prashant
Date: 2024
Description: There have been numerous reports of Powdered Infant Formula (PIF) recalls and outbreaks due to the absence of a kill step in the post...
Show moreThere have been numerous reports of Powdered Infant Formula (PIF) recalls and outbreaks due to the absence of a kill step in the post-pasteurization processing, improper handling pre and post processing and/or reconstitution, and lack of effective sanitization and cleaning of the food contact surfaces in the manufacturing facilities. The objectives of this present study were to 1) survey and identify background microflora in commercial PIF products through microbiological analysis, 16S rRNA, and whole genome sequencing (WGS); 2) compare the survival rate of a known Cronobacter sakazakii and a newly isolated Bacillus cereus DFPST-SP1 in PIF under a humidity level of 33 ± 3% over a period of 28 d; 3) examine the relative resistance of these two strains to thermal treatments at temperatures 40, 70, and 100 °C followed by storage at room temperature (RT) for 30 min; and 4) evaluate the bactericidal effect of 70% ethanol on the two artificially deposited bacterial strains on stainless steel (SS) and plastic coupons. Three biological trials were conducted for each study. To determine whether the increase, decrease, or difference in the bacterial populations and other parameters like water activity (aw) was statistically significant, a T-test was performed (p ≤ 0.05 was considered significant). Results of 16S rRNA sequencing revealed the presence of certain bacterial species in PIF, such as Lactococcus lactis, B. cereus, Listeria monocytogenes, Staphylococcus aureus, Salmonella enterica, etc. distributed across a relative abundance of >25%, <25%, and ≤3%. After the enrichment and isolation as per Bacteriological Analytical Manual (BAM), C. sakazakii or S. enterica were not detected, while colonies exhibiting a blue-green appearance resembling Listeria spp. and certain Bacillus spp. were subjected to WGS for species-level identification. The assembly_1 from formulation 1 was confirmed as B. cereus sequence type 2255 and was renamed as B. cereus DFPST-SP1 in the contribution of this thesis work. The storage study conducted on PIF inoculated with C. sakazakii and B. cereus DFPST-SP1 at 33% RH showed that there was 0.25-0.27 log CFU/g reduction towards the end of 28 d, but no significant difference was observed between the two strains. The thermal challenge study revealed that the newly isolated B. cereus strain and C. sakazakii used in this study were highly thermotolerant. Based on the sanitizer challenge study, 70% ethanol was significantly more effective in reducing populations of C. sakazakii as compared to B. cereus. Moreover, higher log reductions of C. sakazakii 587 populations on stainless steel coupons compared to plastic coupons were observed, indicating that bacteria adhere more tightly to plastic surfaces than stainless steel (SS). Overall, the findings of this study shed new light on bolstering the safety standards of PIF and highlight the need for improved cleaning and sanitization procedures within manufacturing facilities in order to ensure the safety of reconstituted PIF, thereby enhancing public health, particularly infants and neonates.
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Title: Three Essays on the Internet Economy
Creator: Sun, Yidan
Date: 2024
Description: In an era of digital platforms, the integrity and visibility of consumer reviews, the dynamics of digital advertising markets, and the role of...
Show moreIn an era of digital platforms, the integrity and visibility of consumer reviews, the dynamics of digital advertising markets, and the role of software development kits (SDKs) emerge as pivotal elements shaping user experiences and platform economics. My research spans three distinct but interconnected domains: the impact of safety reviews on Airbnb, the effects of privacy protections on digital advertising markets, and the significance of SDK releases in the evolution of Apple's iOS app market. We find that critical reviews concerning the safety of an Airbnb listing's vicinity influence guest bookings negatively and, therefore, could boost platform revenues if such reviews were obscured, highlighting a misalignment between consumer interests and platform revenue objectives. This effect is more pronounced in low-income and minority neighborhoods, suggesting a nuanced impact on different community segments. In the digital advertising sector, we identify that data frictions disproportionately harm small publishers, especially when associated with smaller ad intermediaries, underscoring the vulnerability of niche players to market and regulatory changes. Lastly, our analysis of the iOS app market reveals the instrumental role of SDK releases in fostering the app ecosystem's growth, independent of the expanding iPhone user base. Together, these findings underscore the complex interplay between consumer feedback, technological advancements, and market dynamics in digital environments, urging a balanced approach that safeguards consumer interests while fostering innovation and equitable market practices.
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Title: HIGH PRESSURE GAS FILLED RF CAVITY BEAM TEST AT THE FERMILAB MUCOOL TEST AREA
Creator: Freemire, Ben
Date: 2013, 2013-05
Description: The high energy physics community is continually looking to push the limits with respect to the energy and luminosity of particle accelerators...
Show moreThe high energy physics community is continually looking to push the limits with respect to the energy and luminosity of particle accelerators. In the realm of leptons, only electron colliders have been built to date. Compared to hadrons, electrons lose a large amount of energy when accelerated in a ring through synchrotron radiation. A solution to this problem is to build long, straight accelerators for electrons, which has been done with great success. With a new generation of lepton colliders being conceived, building longer, more powerful accelerators is not the most enticing option. Muons have been proposed as an alternative particle to electrons. Muons lose less energy to synchrotron radiation and a Muon Collider can provide luminosity within a much smaller energy range than a comparable electron collider. This allows a circular collider to be built with higher attainable energy than any present electron collider. As part of the accelerator, but separate from the collider, it would also be possible to allow the muons to decay to study neutrinos. The possibility of a high energy, high luminosity muon collider and an abundant, precise source of neutrinos is an attractive one. The technological challenges of building a muon accelerator are many and diverse. Because the muon is an unstable particle, a muon beam must be cooled and accelerated to the desired energy within a short amount of time. This requirement places strict requisites on the type of acceleration and focusing that can be used. Muons are generated as tertiary beams with a huge phase space, so strong magnetic fields are required to capture and focus them. Radio frequency (RF) cavities are needed to capture, bunch and accelerate the muons. Unfortunately, traditional vacuum RF cavities have been shown to break down in the magnetic fields necessary for capture and focusing. To successfully operate RF cavities in strong magnetic fields, the idea of filling xv them with a high pressure gas in order to mitigate breakdown was proposed. The gas has the added benefit of providing cooling for the beam. Experiments were successfully performed using different gas species in a test cell cavity placed in a multi-Tesla magnetic field. These encouraging results lead to the necessity of a test closer to actual accelerator conditions, namely sending a beam of particles through the cavity. The electron-ion plasma created in the cavity by the beam absorbs energy and can degrade the accelerating electric field of the cavity. Electrons can recombine with hydrogen ions, however this process is slow compared to the bunch length and spacing. As electrons account for the majority of the energy loss in the cavity, their removal in a short time is highly desirable. The addition of an electronegative dopant gas can greatly decrease the lifetime of an electron in the cavity. The results of two beam tests will be presented. The experimental variables cover a wide range of gas pressure, beam intensity, and cavity electric field. Measurements in pure hydrogen of the power consumption of electrons in the cavity indicate a range of energy loss between 10−18 and 10−16 joules per RF cycle per electron. When hydrogen doped with dry air is used, measurements of the power consumption indicate an energy loss range of 10−20 to 10−18 joules per RF cycle per ion, two orders of magnitude improvement over non-doped measurements. The rate at which electrons recombine with positively charged hydrogen ions ranges from 10−7 to 10−5 cm3 s . The lifetime of electrons in a mixture of hydrogen gas and dry air has been measured from <1 ns, up to 200 ns. Finally, the ion-ion recombination rate falls between 10−8 and 10−7 cm3 s . The results extrapolated to the parameters of a Neutrino Factory and Muon Collider indicate that a high pressure gas filled RF cavity will work in a coolingchannel for either machine. A demonstration experiment is warranted to prove this technology’s validity.
PH.D in Physics, May 2013
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Title: AN ITERATIVE APPROACH TO COMBINED IMAGE REGISTRATION AND SEGMENTATION WITH APPLICATIONS TO PROSTATE CANCER IMAGING
Creator: Bukowy, John
Date: 2012-04-19, 2012-05
Description: Machine learning techniques have shown to be a viable means of analyzing medical images for tumor segmentation. Implementation of classi ers...
Show moreMachine learning techniques have shown to be a viable means of analyzing medical images for tumor segmentation. Implementation of classi ers used for tu- mor segmentation requires training data constructed from known data sets. In most applications, obtaining the training dataset requires image registration. This thesis proposes a new combined image registration-segmentation framework to be applied to prostate tumor segmentation in MR images in the future. In order to construct training sets, known pathology from histological slides must be transferred to the MR images. Both manual and automated registration techniques have been previ- ously developed to accomplish this information transfer. Automated methods provide a reproducible, measurable result; however there is still room for improvement. The focus of this thesis is on improvement of the accuracy of the training data set through an iterative approach combining automated registration and segmenta- tion. The performance of the automated method of registration improves with an increase in the number of landmarks for matching. These extra landmarks used for registration are obtained from tumor segmentation; hence the name iterative segmentation-registration. This improvement leads to more accurate data transfer between histology and MR images and hence more accurate training data. Through numerical simulations, we show that by increasing the number of landmarks, using not only anatomical features but obtained segmentation results, the quality of the train- ing data can be improved. The proposed method results in a measurable increase in registration performance which leads to improved training data and consequently improved tumor segmentation performance.
M.S. in Electrical Engineering, May 2012
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Title: SEISMIC COLLAPSE EVALUATION OF NON-DUCTILE CONCENTRICALLY BRACED FRAMES
Creator: Wen, Rou
Date: 2012-11-21, 2012-12
Description: More attentions have been paid on the Non-Ductile Concentrically Braced Frames (ND-CBFs) in low and moderate seismicity regions recently due...
Show moreMore attentions have been paid on the Non-Ductile Concentrically Braced Frames (ND-CBFs) in low and moderate seismicity regions recently due to their low ductility detailing requirements for design and construction. In this work, seismic collapse performances of two ND-CBFs are studied. One 3-story and one 9-story ND-CBF using small response modification coefficients (R=3) are designed firstly. Nonlinear finite element technologies are used to study the behaviors of local components. Practical analytical models for brace/gusset-plate assemblies and steel gravity frames are developed based on finite element simulations and engineering judgment. Three 2D structural models having increased local modeling complexity are developed for each braced frame. Nonlinear static pushover analyses on 3-story frames are conducted to get basic understandings of the damage evolution patterns and the interactions between main brittle braced frames and the steel gravity frames. Nonlinear dynamic analyses references the concepts of Incremental Dynamic Analysis are followed to investigate the seismic collapse responses of studied frames. The seismic assessments referenced the evaluation methods in FEMA P695 for ductile seismic load resisting frames through incremental dynamic analysis are carried out. Studied results show that Non-Ductile Concentrically Braced Frames would have little chance to prevent building collapse under severe ground motions. However, it seems that such buildings at least with low-to-moderate heights would have high probability of collapse prevention for up to moderate ground motions with conventional gravity framing systems used in modern steel buildings.
PH.D in Civil Engineering, December 2012
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Title: CHILD AND PARENT PSYCHOPATHOLOGY: COMBINATIONS RELATED TO THERAPY ATTENDANCE AND PROGRESS
Creator: Giannone, Carolyn D.
Date: 2012-04-30, 2012-05
Description: Disruptive behavior disorders (DBDs) are among the most common and challenging diagnoses in children. It is well documented that family...
Show moreDisruptive behavior disorders (DBDs) are among the most common and challenging diagnoses in children. It is well documented that family therapy services can provide effective treatment for DBDs, but therapy dropout rates are high. This leaves many children untreated, particularly in urban settings. Literature supports relationships between several variables and premature termination of therapy services, including child gender, child psychopathology, parent psychopathology, and perceived barriers to treatment participation. The current study aimed explore if combinations of parent and child psychopathology and their relationship related to therapy completion. Multiple imputation was utilized due to the presence of several missing data points. Results indicated that combinations did not significantly predict therapy completion. Implications of the research, limitations, and suggestions for future research are discussed.
Ph.D. in Clinical Psychology, May 2012
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Title: ASSESSMENT OF STRUCTURAL MATERIALS BY HIGH TEMPERATURE INSTRUMENTED INDENTATION
Creator: Gan, Bin
Date: 2012-12-03, 2012-12
Description: This is an ideal place for me to express my gratefulness to my Ph.D. advisor, Prof. Sammy Tin, who has offered me the financial support and...
Show moreThis is an ideal place for me to express my gratefulness to my Ph.D. advisor, Prof. Sammy Tin, who has offered me the financial support and tremendous freedom in doing research. From working with me through publications and thesis, mentoring me what constitutes a professional and high quality work, nurturing my patience, to giving me advice on how to deliver an insightful presentation, Prof. Tin puts his effort in helping me on every small step that I need to make, as I gradually become more experienced in research and start to make a few achievement along the way. I am deeply indebted to Prof. Tin’s vision, guidance and sustained support. I would like to thank Prof. Philip Nash, Prof. Sheldon Mostovoy and Prof. Sudhakar Nair for being the committee member of my thesis defense, and offering me so many invaluable suggestions. The indispensable help from Russ Janota, the faculty and staff in the MMAE department is acknowledged. The enjoyable interaction with Mengtao, Qizheng, Matt, and other TPTC friends helps me in various aspects. I would like to thank Dr. Hideyuki Murakami and Dr. Takahito Ohmura for hosting me in NIMS. The experience had broadened my horizon and tremendously enhanced my capabilities to conduct independent research. In addition, the research collaboration with Prof. Julia R. Greer and Dr. Robert Maass on freestanding Ni3Al nanoparticles is also fully acknowledged. Furthermore, I am grateful to Prof. Qiang Feng and Prof. Roman Nowak. Their constant support, encouragement, mentoring and nurturing have a profound influence on me. This thesis is dedicated to my beloved parents, Jinlong Gan and Yuxiang Lai, who have built the fortitude into my mind. I also thank my sisters, Liping Gan and Lihong Gan, for their sustained support. Their love and understanding enable me to have a peaceful mind that makes this study possible. I also feel grateful to the deep love and endless patience from Xiaomo Li and the support from her parents.
PH.D in Materials Science and Engineering, December 2012
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Title: BLOCK COPOLYMER BASED MICELLE FOR EFFICIENT IMMUNOSENSING
Creator: Li, Ying
Date: 2012-11-26, 2012-12
Description: This thesis demonstrates the formation of micelles from a block copolymer and the application in establishing the micelle based immunosensing...
Show moreThis thesis demonstrates the formation of micelles from a block copolymer and the application in establishing the micelle based immunosensing system. The utilization of polymeric micelle as probe container and antibody carrier increases the probe to antibody ratio, which is expected to leads to better detection efficiency. The substrate used in the immunosensing is a porous 0.45 μm PVDF membrane which allows the stable immobilization of proteins. Tetraphenylporphyrin, a hydrophobic fluorescent dye, was chosen as the probe encapsulated in micelles. The block copolymer is a self synthesized α-carboxyl-ω-hydroxyl terminated Poly(ethylene oxide)-Polycaprolactone with carboxyl group on the hydrophilic end, permitting the conjugation of antibody to the micelle surface. We choose mouse IgG and its antibody anti-IgG as the pair of protein conjugates to demonstrate the immunoassay. So far, the detection limit of mouse IgG is 1.5 μg/ml (10-8 M) in this immunosensing system, which is expected to improve by modifying the system.
M.S. in Chemistry, December 2012
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