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1,716 Matching Results
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Investigating Human Gut Microbiome in Obesity with Machine Learning Methods
Obesity is a common disease among all ages that has threatened human health and has become a global concern. Gut microbiota can affect human metabolism and thus may modulate obesity. Certain mixes of gut microbiota can protect the host to be healthy or predispose the host to obesity. Modern next-generation sequencing technique allows accessing huge amount of genetic information underlying microbiota and thus provides new insights into the functionality of these micro-organisms and their interactions with the host. Multiple previous studies have demonstrated that the microbiome might contribute to obesity by increasing dietary energy harvest, promoting fat deposition and triggering systemic inflammation. However, these researches are either based on lab cultivation studies or basic statistical analysis. In order to further explore how gut microbiota affect obesity, this thesis utilize a series of machine learning methods to analyze large amount of metagenomics data from human gut microbiome. The publicly available HMP (Human Microbiome Project) metagenomic sequencing data, contain microbiome data for healthy adults, including overweight and obese individuals, were used for this study. HMP gut data were organized based on two different feature definitions: taxonomic information and metabolic reconstruction information. Several widely used classification algorithms: namely Naive Bayes, Random Forest, SVM …
Date:
August 2017
Creator:
Zhong, Yuqing
System:
The UNT Digital Library
A Preliminary Evaluation of an Indirect Assessment of Sensitivity to Aversive Stimulation
Aversive tasks and activities are commonly encountered in the everyday routines of most individuals. For individuals with intellectual disabilities, a means to assess individual sensitivities to aversive stimulation could allow caregivers to avoid unnecessary contact with aversive events, teach appropriate ways to avoid or escape aversive situations, and condition tolerance to unavoidable aversive tasks and activities. The current study, conducted at a large, state-operated residential facility for adults with intellectual disabilities, used an anecdotal assessment, the Sensitivities to Aversive Stimulation Survey (SASS), to evaluate the relative aversiveness of an array of commonly encountered tasks and activities for each participant. Five caregivers complete the 25-question assessment, using Likert-type scales to rate individual participants' affect, compliance or tolerance, and severity of problem behavior related to each item. The mean scores of the raters were used to estimate the aversiveness of each task, condition, or activity. The outcomes from the SASS were then compared with outcomes of an experimental analysis in which participants could emit responses to escape situations that were ranked either high or low using the SASS. Relative aversiveness was evaluated by comparing the percentage of trials with escape behavior and duration of exposure for each stimulus. Preliminary results indicate that …
Date:
August 2017
Creator:
Hope, Mariah L.
System:
The UNT Digital Library
Synthesis and Application of New Chiral Ligands for Enantioselectivity Tuning in Transition Metal Catalysis
A set of five new C3-symmetric phosphites were synthesized and tested in palladium-catalyzed asymmetric Suzuki coupling. The observed reactivity and selectivity were dependent upon several factors. One of the phosphites was able to achieve some of the highest levels of enantioselectivity in asymmetric Suzuki couplings with specific substrates. Different hypotheses have been made for understanding the ligand effects and reaction selectivities, and those hypotheses were tested via various methods including DOSY NMR experiments, X-ray crystallography, and correlation of catalyst selectivity with Tolman cone angles. Although only modest enantioselectivities were observed in most reactions, the ability to synthesis these phosphites in only three steps on gram scales and to readily tune their properties by simple modification of the binaphthyl 2´-substituents makes them promising candidates for determining structure-selectivity relationships in asymmetric transition metal catalysis, in which phosphites have been previously shown to be successful. A series of novel chiral oxazoline-based carbodicarbene ligands was targeted for synthesis. Unfortunately, the chosen synthetic route could not be completed due to unwanted reactivity of the oxazoline ring. However, a new and efficient route for Pd-catalyzed direct amination of aryl halides with oxazoline amine was developed and optimized during these studies. Chiral binaphthyl based Pd(II) ADC complexes …
Date:
August 2017
Creator:
Kong, Fanji
System:
The UNT Digital Library
BLE Controller Module for Wireless Sensor Networks
Sensors have been an integral part of our life since a long time. Traditionally, the transmit information to a data collection center through a physical wire. However, with the introduction of Bluetooth Low Energy (BLE) communication protocol, more research is being done into the field of wireless sensor networks (WSN). BLE was introduced to target low power applications. The CC2650 Launchpad designed by Texas Instruments (TI) can lead to a bulky final product. The aim was to design hardware for the CC2650 micro-controller with the aim of making it more compact for use in WSNs. A top-down approach was used wherein the available product is studied to identify the redundant and reverse engineer it to design a new product. A 2 layer printed circuit board (PCB) was designed which resulted in a 64 percent decrease in size compared to the Launchpad. Also, experiments were performed to test the proof of concept.
Date:
August 2017
Creator:
Vaswani, Mohit Suresh
System:
The UNT Digital Library
Optimization of an SDR Based Aerial Base Station
Most times people are unprepared to face natural disasters resulting in chaos, increased number of deaths, etc.Emergency responders need an efficiently working communication network to get in touch with the emergency services like hospitals, police, fire and rescue as well as people who are stranded. Such a network is also the need of the hour for survivors to contact their near and dear ones. One of the major barriers of communication during an emergency is the destruction of network elements. In case the communication devices survive the calamity, odds of the network getting congested are certainly high because almost everyone will be trying to use the same network resources. An important factor when dealing with emergency situations is the calls for an immediate response and an efficient Emergency Communication Systems (ECS). Currently there is a capability gap between existing ECS solutions and what we dream of achieving. Most current solutions do not meet cost or mobility constraints. An inexpensive, portable and mobile system will fulfill this capability gap. The main purpose of this research is to optimize the altitude and received signal strength of an aerial base station to provide maximum radio coverage on the ground as well as propose …
Date:
August 2017
Creator:
Mathews, Steffy Ann
System:
The UNT Digital Library
Cultural Humility, Religion, and Health in Lesbian, Gay, and Bisexual (LGB) Populations
The purpose of this study was to explore the religion – health link in a sample of adults and undergraduate students (N = 555) that identified as lesbian, gay, or bisexual (LGB), and to explore how perceptions of cultural humility of religious individuals and groups toward LGB individuals affect the relationship between religion and health. First, I found religious commitment among LGB individuals was positively correlated with satisfaction in life, but it was negatively correlated with physical health. Second, I found that cultural humility moderated the relationship between religious commitment and satisfaction in life for LGB individuals involved in a religious community. The lowest levels of satisfaction with life were found for individuals with low religious commitment and perceived the cultural humility of their religious community to be low. However, cultural humility did not moderate the relationship between religious commitment and mental and physical health outcomes. Third, I found cultural humility did not moderate the relationship between religious commitment and minority stress (i.e., internalized homophobia). Fourth, I found that cultural humility was a significant positive predictor of motivations to forgive a hurt caused by a religious individual. I conclude by discussing limitations, areas for future research, and implications for counseling.
Date:
August 2017
Creator:
Mosher, David K.
System:
The UNT Digital Library
Development and Analysis of a Mobile Node Tracking Antenna Control System
A wireless communication system allows two parties to exchange information over long distances. The antenna is the component of a wireless communication system that allows information to be converted into electromagnetic radiation that propagates through the air. A system using an antenna with a highly directional beam pattern allows for high power transmission and reception of data. For a directional antenna to serve its purpose, it must be accurately pointed at the object it is communicating with. To communicate with a mobile node, knowledge of the mobile node's position must be gained so the directional antenna can be regularly pointed toward the moving target. The Global Positioning System (GPS) provides an accurate source of three-dimensional position information for the mobile node. This thesis develops an antenna control station that uses GPS information to track a mobile node and point a directional antenna toward the mobile node. Analysis of the subsystems used and integrated system test results are provided to assess the viability of the antenna control station.
Date:
August 2017
Creator:
Hensley, Phillip H.
System:
The UNT Digital Library
Grand Canyons: Authoritative Knowledge and Patient-Provider Connection
In 2011, African Americans in Tarrant County, Texas experienced an infant mortality rate of 14.3 per 1,000 live births. The leading cause of infant mortality in Tarrant County is prematurity and maternal nutritional status. Both maternal under-nutrition and over-nutrition are known risk factors for premature birth. Improving maternal nutrition, by reducing rates of gestational diabetes and preeclampsia, and by increasing consumption of essential prenatal vitamins and nutrients, is a road to decreasing preterm birth in African Americans. This qualitative study, based on both anthropology and public health theory, of the nutrition behavior of a group of African American expectant mothers and the experience of their health care providers and co-facilitators had a goal to provide a foundation for future development of nutrition behavior research and education for this specific population. The main finding of this study was the substantial gap of lived experience and education between the patients and their providers and co-facilitators, which hinders delivery of care and the patients’ acquiescence to nutrition recommendations. The discrepancies between the authoritative knowledge of the providers and the bodily knowledge of expectant mothers were responsible for the ineffectiveness of nutrition recommendations.
Date:
May 2015
Creator:
Fowler, Rebecca (Public health researcher)
System:
The UNT Digital Library
Electrochemical Deposition of Nickel Nanocomposites in Acidic Solution for Increased Corrosion Resistance
The optimal conditions for deposition of nickel coating and Ni-layered double hydroxide metal matrix composite coatings onto stainless steel discs in a modified all-sulfate solutions have been examined. Nickel films provide good general corrosion resistance and mechanical properties as a protective layer on many metallic substrates. In recent years, there has been interest in incorporation nano-dimensional ceramic materials, such as montemorillonite, into the metal matrices to improve upon the corrosion and mechanical properties. Layered double hydroxides have been used as corrosion enhancer in polymer coatings by increasing mechanical strength and lowering the corrosion rate but until now, have not been incorporated in a metal matrix by any means. Layered double hydroxides can be easily synthesized in a variety of elemental compositions and sizes but typically require the use of non-polar solvents to delaminate into nanodimensional colloidal suspensions. The synthesis of a Zn-Al LDH has been studied and characterized. The effects of the non-polar solvents dimethylformamide and n-butanol on the deposition and corrosion resistance of nickel coatings from a borate electrolyte bath have been studied, a nickel-LDH nanocomposite coating has been synthesized by electrochemical deposition and the corrosion resistance has been studied. Results indicate an improvement in corrosion resistance for the …
Date:
August 2017
Creator:
Daugherty, Ryan E.
System:
The UNT Digital Library
A Convergence Analysis of LDPC Decoding Based on Eigenvalues
Low-density parity check (LDPC) codes are very popular among error correction codes because of their high-performance capacity. Numerous investigations have been carried out to analyze the performance and simplify the implementation of LDPC codes. Relatively slow convergence of iterative decoding algorithm affects the performance of LDPC codes. Faster convergence can be achieved by reducing the number of iterations during the decoding process. In this thesis, a new approach for faster convergence is suggested by choosing a systematic parity check matrix that yields lowest Second Smallest Eigenvalue Modulus (SSEM) of its corresponding Laplacian matrix. MATLAB simulations are used to study the impact of eigenvalues on the number of iterations of the LDPC decoder. It is found that for a given (n, k) LDPC code, a parity check matrix with lowest SSEM converges quickly as compared to the parity check matrix with high SSEM. In other words, a densely connected graph that represents the parity check matrix takes more iterations to converge than a sparsely connected graph.
Date:
August 2017
Creator:
Kharate, Neha Ashok
System:
The UNT Digital Library
Formation Control of Multi-Agent Systems
Formation control is a classical problem and has been a prime topic of interest among the scientific community in the past few years. Although a vast amount of literature exists in this field, there are still many open questions that require an in-depth understanding and a new perspective. This thesis contributes towards exploring the wide dimensions of formation control and implementing a formation control scheme for a group of multi-agent systems. These systems are autonomous in nature and are represented by double integrated dynamics. It is assumed that the agents are connected in an undirected graph and use a leader-follower architecture to reach formation when the leading agent is given a velocity that is piecewise constant. A MATLAB code is written for the implementation of formation and the consensus-based control laws are verified. Understanding the effects on formation due to a fixed formation geometry is also observed and reported. Also, a link that describes the functional similarity between desired formation geometry and the Laplacian matrix has been observed. The use of Laplacian matrix in stability analysis of the formation is of special interest.
Date:
August 2017
Creator:
Mukherjee, Srijita
System:
The UNT Digital Library
Design fully-integrated dual-band two-stage class-E CMOS PA
In retrospect we can see that from the last century, wireless electronic technology has been in a rapid state of development. With the popularity of wireless communication, the power amplifier demand is rising. In general, magnitude, maximum noise figure, minimum noise figure, efficiency, and output power are important indicators of the amplifier. The IC industry is exploring how to reduce the additional cost and improve the high-frequency performance. Therefore, designing a strong adaptability and high cost performance of the PA has become a priority. As these technologies advance, the power amplifiers need to have better integration, lower cost, and lower power dissipation. Also, some special requirements are being asked in some areas, such as multi-mode and multi-band. In general, people have to use several power amplifiers parallel to frame a multifunction chip. Each of them working at different frequencies of interest has to have separate matching network, design, and area; also, the diversity amplifier prices will increase with the number of amplifiers, and its cost is also changed. In this thesis, because Class E power amplifier has lower power dissipation, 100% ideal efficiency, simple circuit structure, and strong applicability, the Class E is used as power amplifier in main stage. …
Date:
August 2015
Creator:
Zhao, Chao (Electrical engineering researcher)
System:
The UNT Digital Library