You limited your search to:

  Partner: UNT Libraries
Carbon Nanostructure Based Donor-acceptor Systems for Solar Energy Harvesting
Carbon nanostructure based functional hybrid molecules hold promise in solarenergy harvesting. Research presented in this dissertation systematically investigates building of various donor-acceptor nanohybrid systems utilizing enriched single walled carbon nanotube and graphene with redox and photoactive molecules such as fullerene, porphyrin, and phthalocyanine. Design, synthesis, and characterization of the donor-acceptor hybrid systems have been carefully performed via supramolecular binding strategies. Various spectroscopic studies have provided ample information in terms of establishment of the formation of donor-acceptor hybrids and their extent of interaction in solution and eventual rate of photoinduced electron and/or energy transfer. Electrochemical studies enabled construction of energy level diagram revealing energetic details of the possible different photochemical events supported by computational studies carried out to establish the HOMO-LUMO levels in the donor acceptor systems. Transient absorption studies confirmed formation of charge separated species in the donor-acceptor systems which have been supported by electron mediation experiments. Based on the photoelectrochemical studies, IPCE of 8% was reported for enriched SWCNT(7,6)-ZnP donor-acceptor systems. In summary, the present investigation on the various nanocarbon sensitized donor-acceptor hybrids substantiates tremendous prospect, that could very well become the next generation of materials in building efficient solar energy harvesting devices andphotocatalyst. digital.library.unt.edu/ark:/67531/metadc407823/
In-store Event Needs and Technology Use Among Half Price Books Customers
Half Price Books, Records, Magazines, Inc. (HPB), fills a unique niche by selling a variety of new, used and rare merchandise primarily in their chain of 116 stores in sixteen states and online. The company has noticed increased mobile device use among customers in their stores while sales have declined in recent years. To remain viable HPB is attempting to adapt to market forces in a timely manner while remaining continually interested in growth and innovation. A major part of adapting, growing, and innovating is the adoption and astute utilization of technology in-store and a more complete understanding of their customers’ activities and preferences. The goal is to make Half Price Books a more technologically savvy destination for shopping, community events, and entertainment. One purpose of this study is to give the company a better idea of how customers use technology in searching for merchandise including information searches generated in-store from mobile devices and how customers use the internet to find merchandise prior to and following their experiences in HPB’s stores. Another important purpose is to also determine what kinds of events such as book signings, poetry readings and other special events customers would like to see at Half Price Books, since the company has indicated a strong desire to provide fun and memorable experiences as well as products. The major research aims of this study are (1) To explore how customers use technology in searching for books in relation to two Half Price Books locations in Arlington, Texas and (2) To determine what customers want in terms of in-store events at these same locations. digital.library.unt.edu/ark:/67531/metadc407803/
Dynamic Precipitation of Second Phase Under Deformed Condition in Mg-nd Based Alloy
Magnesium alloys are the lightweight structural materials with high strength to weigh ratio that permits their application in fuel economy sensitive automobile industries. Among the several flavors of of Mg-alloys, precipitation hardenable Mg-rare earth (RE) based alloys have shown good potential due to their favorable creep resistance within a wide window of operating temperatures ranging from 150°C to 300°C. A key aspect of Mg-RE alloys is the presence of precipitate phases that leads to strengthening of such alloys. Several notable works, in literature, have been done to examine the formation of such precipitate phases. However, there are very few studies that evaluated the effect stress induced deformation on the precipitation in Mg-RE alloys. Therefore, the objective of this work is to examine influence of deformation on the precipitation of Mg-Nd based alloys. To address this problem, precipitation in two Mg-Nd based alloys, subjected to two different deformation conditions, and was examined via transmission electron microscopy (TEM) and atom probe tomography (APT). In first deformation condition, Md-2.6wt%Nd alloy was subjected to creep deformation (90MPa / 177ºC) to failure. Effect of stress-induced deformation was examined by comparing and contrasting with precipitation in non-creep tested specimens subjected to isothermal annealing (at 177ºC). In second condition, Mg-4.0Y-3.0Nd-0.5Zr (wt %) or WE43 alloy (with comparable Nd content as model Mg-Nd system) was subjected to hot rolling deformation at a sub-solvus temperature. digital.library.unt.edu/ark:/67531/metadc407807/
Designing Tools to Probe the Calcium-dependent Function of Arabidopsis Tonneau2
Access: Use of this item is restricted to the UNT Community.
Plants possess unique features in many aspects of development. One of these features is seen in cell wall placement during cytokinesis, which is determined by the position of the preprophase band (PPB) and the subsequent expansion of the phragmoplast that deposits the new cell wall. During phragmoplast expansion, the phragmoplast tracks to the cortical division site, which was delineated by the PPB. Thus the position of the PPB determines the orientation of the division plane. In Arabidopsis thaliana, TONNEAU2 (TON2) is required for PPB formation and has been shown to interact with a type A subunit of the PP2A phosphatase in the yeast two-hybrid system. In Arabidopsis tonneau2 (ton2) mutants, abnormalities of the cortical microtubule cytoskeleton, such as disorganization of the interphase microtubule array and lack of PPB formation before mitosis markedly affects cell shape and arrangement as well as overall plant morphology. Loss of dcd1/add1, the maize ton2 homologues gives rise to a similar phenotype in Zea mays. The TON2 protein has two EF hand domains which are calcium-binding sites. Since calcium has been known to play key roles in several areas of plant functioning, the following question was raised: “Does calcium binding contribute to the localization and function of TONNEAU at the PPB?” To address this question, a series of constructs were generated to determine if TON2 binds calcium. Additionally, Ca2+ binding sites were mutated in constructs containing the TON2 gene fused to GFP or YPF. These constructs were then transformed into ton2 mutant plants and the localization of TON2 fusion protein and whether the construct is capable of rescuing the mutant phenotype were observed. Although, localization of TON2 to the PPB was not observed, the presence of the constructs were confirmed in the transformed plants using selection markers and by observing fluorescence under a confocal microscope. digital.library.unt.edu/ark:/67531/metadc407800/
Field and Laboratory Fish Tissue Accumulation of Carbamazepine and Amiodarone
The goals of this dissertation work were to assess the bioaccumulation potential of carbamazepine and amiodarone, two widely used ionizable pharmaceutical compounds that possess mid-range and high LogD values, respectively, and to evaluate alternative methods to assess chemical accumulation in bluntnose minnows, catfish, and tilapia. Results indicated that carbamazepine does not appreciably bioaccumulate in fish tissue with BCFk and BAF carbamazepine values < 10. Amiodarone, however, with a log D of 5.87 at pH 7.4, accumulated in fish tissues with kinetic BCF values <2,400. Collectively, the data suggest that full and abbreviated laboratory-derived BCFs, BCFMs derived from S9 loss-of-parent assays, as well as field BAF values are similar for each of the two drugs. In summary, the results from this dissertation indicated: 1) The reduced design BCF test is a good estimate for the traditional OECD 305 test. 2) In vitro S9 metabolism assays provide comparable BCF estimates to the OECD 305 test. 3) Metabolism may play a large role in the accumulation of drugs in fish. 4) Reduced BCF tests and in vitro assays are cost effective and can reduce vertebrate testing. digital.library.unt.edu/ark:/67531/metadc407838/
Substitution Effects of Phenothiazine and Porphyrin Dyes in Dye-sensitized Solar Cells
The details of dye sensitized solar cells was explained and phenothiazine and porphyrin based dyes were synthesized for use in DSSCs. DSSCs offer a unique and cost effective method of renewable energy. DSSCs are characterized through various tests, with the overall efficiency, η, bearing the greatest importance. Incident photon to current conversion efficiency, or IPCE, is also another important characterization of DSSCs. Effect of positioning of the cyanoacrylic acid anchoring group on ring periphery of phenothiazine dye on the performance of dye sensitized solar cells (DSSCs) is reported. The performances of the cells are found to be prominent for solar cells made out of Type-1 dyes compared to Type-2 dyes. This trend has been rationalized based on spectral, electrochemical, computational and electrochemical impedance spectroscopy results. Free-base and zinc porphyrins bearing a carboxyl anchoring group at the para, meta, or ortho positions of one of the meso-phenyl rings were synthesized for DSSCs. Photoelectrochemical studies were performed after immobilization of porphyrins onto nanocrystalline TiO2. The performance of DSSCs with the porphyrin anchoring at the para or meta position were found to greatly exceed those in the ortho position. Additionally, zinc porphyrin derivatives outperformed the free-base porphyrin analogs, including better dye regeneration efficiency for the zinc porphyrin derivatives and for the meta and para derivatives through electrochemical impedance spectroscopy studies. The overall structure-performance trends observed for the present porphyrin DSSCs have been rationalized based on spectral, electrochemical, electrochemical impedance spectroscopy and transient spectroscopy results. digital.library.unt.edu/ark:/67531/metadc407837/
Correlates of Depression in Elderly Asians in the United States
The primary purpose of this study was to examine the correlation between depression and the personal characteristics of Asians who are 50 years or older. The secondary objective was to determine whether Asians 50 years or older living in the United States are more likely to be depressed than other ethnicities. The information for this study was secured from the National Health Interview Survey, spanning the years 2001 to 2010. In this study, I utilized the SAS-Callable SUDAAN statistical system. Multivariate regression was used to predict and determine significant correlations. The results indicated that Asians 50 and older living in the U.S. and who experience functional limitations, poor vision, hypertension, poor health, not married, and unemployed in previous year were in general more prone to depression. Furthermore, the study indicated that Asian elderly living the U.S. showed lower rates of depression than all non- Asian ethnicities. However when controlled for personal characteristics only Whites and Hispanics had higher depression incidences than Asian elderly. Recommendations for future studies include: conducting more micro and macro studies of Asian elders, such as in-depth case studies for each ethnicity, longitudinal studies of various Asian subgroups, and studies of Asian elderly with hypertension who have committed suicide. digital.library.unt.edu/ark:/67531/metadc407809/
An Age-based Etic Analysis of Orthographic Variation in Computer-mediated French Discourse
This study examines orthographic variation in synchronous computer-mediated French discourse. All nontraditional variations of selected frequently occuring items are quantified in order to provide an etic (i.e., from an external perspective) analysis. The primary variable of interest is age since this study focuses on providing a comparison of chat participants in their twenties versus those in their fifties. The widespread claim is that younger people communicate using more informal and/or nontraditional forms than older people; however, the results of the present study suggest that this is not always the case. The main finding of the present study is that the twentysomethings and the fiftysomethings produce the nontraditional orthography in a similar fashion in 52.2% of the terms, and in a non-similar fashion in 47.8% of the terms. Following the presentation and discussion of the results, directions for future research are provided. digital.library.unt.edu/ark:/67531/metadc407821/
Simulating the Spread of Infectious Diseases in Heterogeneous Populations with Diverse Interactions Characteristics
The spread of infectious diseases has been a public concern throughout human history. Historic recorded data has reported the severity of infectious disease epidemics in different ages. Ancient Greek physician Hippocrates was the first to analyze the correlation between diseases and their environment. Nowadays, health authorities are in charge of planning strategies that guarantee the welfare of citizens. The simulation of contagion scenarios contributes to the understanding of the epidemic behavior of diseases. Computational models facilitate the study of epidemics by integrating disease and population data to the simulation. The use of detailed demographic and geographic characteristics allows researchers to construct complex models that better resemble reality and the integration of these attributes permits us to understand the rules of interaction. The interaction of individuals with similar characteristics forms synthetic structures that depict clusters of interaction. The synthetic environments facilitate the study of the spread of infectious diseases in diverse scenarios. The characteristics of the population and the disease concurrently affect the local and global epidemic progression. Every cluster’ epidemic behavior constitutes the global epidemic for a clustered population. By understanding the correlation between structured populations and the spread of a disease, current dissertation research makes possible to identify risk groups of specific characteristics and devise containment strategies that facilitate health authorities to improve mitigation strategies. digital.library.unt.edu/ark:/67531/metadc407831/
Dramatizing Lynching and Labor Protest: Case Studies Examining How Theatre Reflected Minority Unrest in the 1920S and 30S
Theatre is widely unrecognized for the compelling influence it has held in society throughout history. In this thesis, I specifically examine the implications surrounding the social protest theatre of black and Jewish American minority communities in the first half of the twentieth century. I discuss how their historical circumstance, culture, and idiosyncratic natures caused them to choose agitated propaganda theatre as an avenue for protest. I delve into the similarities in circumstance, but their theatre case studies separate the two communities in the end. I present case studies of each community, beginning with anti-lynching plays of the 1920s that were written by black American playwrights both in response to white supremacist propaganda theatre and to assert a dignified representation of the black community. However, their plays and protest movement never developed a larger popular following. My next minority theatre case study is an examination of 1930s Jewish labor drama created in protest of popular anti-Semitic theatre and poor labor conditions. The Jewish community differs from the black community in their case because the racist propaganda was produced by a man who was Jewish. Another difference is that their protest theatre was on the commercial stage by this point because of a rise in a Jewish middle class and improvement of circumstance. Both the Jewish protest theatre and labor reform movements were more successful. My conclusion is a summation of black and Jewish American theatre of the era with a case study of collaboration between the communities in George Gershwin’s operetta about black Americans, Porgy and Bess. I conclude that these two communities eventually departed from circumstance and therefore had differing theatrical, political, and social experiences in America during the 1930s. digital.library.unt.edu/ark:/67531/metadc407832/
Selling Humans: the Political Economy of Contemporary Global Slavery
Human trafficking is a growing illegal crime, both in terms of numbers and profits. Thus, important to consider, as it is a human rights, political, criminal justice, national security, and economic issue. Previous studies have these examined these human trafficking factors independently, yet none have really taken into account how they work simultaneously. This study examines why human trafficker continues to occur, particularly at the domestic and transnational level, and also why some countries are better able to effectively deal with this problem in terms of criminalizing human traffickers. It is argued that at the domestic level, traffickers first must take into account the operating costs, illegal risks, bribery, and profits of the business. After considering these basic elements, they then need to consider the world, including economic, political, geographic, and cultural factors that may help facilitate human trafficking. However, human trafficking can occur across large geographic distances, though rare. This is more likely to happen based on the type of human trafficking group, available expatriate or immigrant networks, the origin-transit-destination country connection, or strength of the bilateral economic relationship between origin and destination countries. Finally, looking at why some countries are better able to criminalize traffickers helps us to better understand how human trafficking can be discouraged. In short, conformity of a country’s domestic anti-human trafficking law, as well as the degree of enforcement, should increase the probability of criminalizing a human trafficker. These three theoretical arguments help to better understand the nature of the business, and more importantly, why human trafficking continues. digital.library.unt.edu/ark:/67531/metadc407818/
Posttraumatic Stress and Neurobehavioral Symptoms
The purpose of this study is to examine the structure of neurobehavioral symptoms in service members with physical and/or psychological trauma to determine the diagnostic specificity of these symptoms. Previous literature has demonstrated that orthopedic injured, mild traumatic brain injury (MTBI), and healthy controls shared similar levels of postconcussive symptom complaints, which suggest that postconcussion-like symptoms are not unique to MTBI. To the best of my knowledge, this is the first study examining this phenomenon in a sample of recently redeployed service members. Dimensional analysis of the PCL-C and NSI using SEM did not produce a model that was consistent with previous literature and principle component analyses did not produce a simple solution for posttraumatic stress or neurobehavioral symptoms. Thus, the study does not provide evidence for construct validity for either instrument. Implications for these findings are that clinicians need to be aware that these instruments may not be measuring coherent constructs within this population as purported and should judiciously interpret and report the results of these instruments. digital.library.unt.edu/ark:/67531/metadc407833/
Catered Learning: an Anthropological Approach to Understanding How Learning Styles of Participants and Teaching Styles of Instructors Affect Participants’ Perception, Motivation, and Performance
Organizations rely on their training departments to deliver adequate training for effective use of knowledge on the job to new and tenured employees. The transfer of learned knowledge and skills yields many positive outcomes for the employees, the trainers, and the organization as a whole. Such outcomes include improved productivity and efficiency, increased morale, work enjoyment, improved customer service, and improved shareholder satisfaction. In order to achieve these outcomes, training departments must employ skilled training personnel knowledgeable about curriculum design and creative with training delivery and learning environments. These requirements implementation will depends heavily on the experience level of training professionals. Training professionals need to understand their own learning styles and how to appropriately utilize strategies to target the various learning styles that exist in the classroom. Instructors must constantly monitor the learning environment and be able to make immediate changes to meet the needs of the participants when necessary. Participants themselves play an integral role in the effective transfer of learning from the classroom to the job. Learners’ backgrounds, life experiences, and motivation to learn are important considerations for designing a positive learning experience. When training programs cater to learners’ preferred learning styles with an appropriate learning environment in mind, the instructor, the learner, and the organization reap numerous benefits. More specifically, when learners’ learning styles are supported by their instructors’ teaching styles, the overall learning experience becomes optimized to the benefit of all stakeholders. digital.library.unt.edu/ark:/67531/metadc407835/
A 018μm Cmos Transmitter for Ecg Signals
Electrocardiography (ECG) signal transmitter is the device used to transmit the electrical signals of the heart to the remote machine. These electrical signals are ECG signals caused due to electrical activities in the heart. ECG signals have very low amplitude and frequency; hence amplification of the signals is needed to strengthen the signal. Conversion of the amplified signal into digital information and transmitting that information without losing any data is the key. This information is further used in monitoring the heart. digital.library.unt.edu/ark:/67531/metadc407805/
Long Distance International Caregiving to Elderly Parents Left Behind: a Case of Nigerian Adult Children Immigrants in Usa
The intent of this qualitative, grounded theory study was to understand why the Nigerian (Igbo) adult immigrants in the United States provide long distance international caregiving to their elderly parents left behind in Nigeria, the challenges they encounter, and their views on long-term service care. This study was grounded in semi-structured interviews of 20 Igbo adult immigrants residing in the Dallas/Fort Worth Metropolis. Analysis of the literature demonstrates a lack of existent topic on long distance international caregiving to elderly parents left behind in Nigeria. Findings show that reasons for Igbo adult children immigrants providing care to their elderly parents left behind stem from filial obligation, immigrant’s position in the family, perceived vulnerability of parents, and lack of government support. Also because of cultural expectations, the participants felt obligated to reciprocate to the care their elderly parents gave to them when they were growing up. While providing long distance international care, the participants encountered some challenges like adjusting to their new country, distance, financial constraints, being available for family procreation, issues with means of communication, and legal papers and parental adjustment to life in the U.S. This study also revealed that the participants would support the Nigerian government and private sector to provide long-term service care for the aging population. The findings led to some policy recommendations. digital.library.unt.edu/ark:/67531/metadc407817/
Energy Harvesting Wireless Piezoelectric Resonant Force Sensor
The piezoelectric energy harvester has become a new powering option for some low-power electronic devices such as MEMS (Micro Electrical Mechanical System) sensors. Piezoelectric materials can collect the ambient vibrations energy and convert it to electrical energy. This thesis is intended to demonstrate the behavior of a piezoelectric energy harvester system at elevated temperature from room temperature up to 82°C, and compares the system’s performance using different piezoelectric materials. The systems are structured with a Lead Magnesium Niobate-Lead Titanate (PMN-PT) single crystal patch bonded to an aluminum cantilever beam, Lead Indium Niobate-Lead Magnesium Niobate-Lead Titanate (PIN-PMN-PT) single crystal patch bonded to an aluminum cantilever beam and a bimorph cantilever beam which is made of Lead Zirconate Titanate (PZT). The results of this experimental study show the effects of the temperature on the operation frequency and output power of the piezoelectric energy harvesting system. The harvested electrical energy has been stored in storage circuits including a battery. Then, the stored energy has been used to power up the other part of the system, a wireless resonator force sensor, which uses frequency conversion techniques to convert the sensor’s ultrasonic signal to a microwave signal in order to transmit the signal wirelessly. digital.library.unt.edu/ark:/67531/metadc407829/
Parameter Estimation Using Consensus Building Strategies with Application to Sensor Networks
Sensor network plays a significant role in determining the performance of network inference tasks. A wireless sensor network with a large number of sensor nodes can be used as an effective tool for gathering data in various situations. One of the major issues in WSN is developing an efficient protocol which has a significant impact on the convergence of the network. Parameter estimation is one of the most important applications of sensor network. In order to model such large and complex networks for estimation, efficient strategies and algorithms which take less time to converge are being developed. To deal with this challenge, an approach of having multilayer network structure to estimate parameter and reach convergence in less time is estimated by comparing it with known gossip distributed algorithm. Approached Multicast multilayer algorithm on a network structure of Gaussian mixture model with two components to estimate parameters were compared and simulated with gossip algorithm. Both the algorithms were compared based on the number of iterations the algorithms took to reach convergence by using Expectation Maximization Algorithm.Finally a series of theoretical and practical results that explicitly showed that Multicast works better than gossip in large and complex networks for estimation in consensus building strategies. digital.library.unt.edu/ark:/67531/metadc407815/
Evaluating the Content and Tone of Mental Health News Coverage in Market 40: a Content Analysis of Selected Internet Stories From Las Vegas Broadcasting News Outlets
The purpose of this research study is to analyze mental health related content on the three network affiliated stations in Las Vegas, Nevada. Online web stories from broadcast stations are analyzed in terms of the content and tone. These areas of analysis relate directly to the mass communication theories agenda setting and framing. Historically, mental health news reports have included content and tone that together can potentially create and further stigmatizing sentiments about those with mental illnesses. This study utilizes a chi square test to determine if a relationship exists between the three network affiliated stations, four a priori coded mental health content categories, and a rating of the overall tone using a value dimensions scale. Supplemental analyses include frequency evaluations of what has been called “people-first” versus “non-people first” language. By analyzing mental health related content at these three stations in the Las Vegas market this study aims to add heuristic value to the study of mental health reporting in broadcast news. This study will allow for additional research to further test relationships between stations, content, and tone in the Las Vegas and other news markets. Ultimately, this study provides analysis and discussion of the important role of agenda setting and framing in the news industry as it relates to the coverage of mental health related content. digital.library.unt.edu/ark:/67531/metadc407804/
Light, Bright, and Out of Sight: Hollywood’s Representation of the Tragic Mulatto
The purpose of this research is to examine the longevity of the stereotype of the tragic mulatto in American film history. Specifically, my research focuses on the portrayals and perceptions of biracial actresses. Media informs, entertains, and influences how we, and especially youth, self-identify and interact with others. This research focuses on the portrayal of biracial actresses throughout film history. It is also important in its investigation of the perpetuation of the one-drop rule. In this research, I will examine if historical stereotypes of tragic mulatto are apparent in contemporary Hollywood film. The methodologies used in this research include a content analysis of films with biracial actresses and an online survey of respondents’ perceptions of four actresses. Statistical techniques used for analysis include ordinary least square regression and multinomial logistic regression. Findings suggest that the tragic mulatto stereotype is not blatant in contemporary Hollywood film, but issues of colorism may be apparent. digital.library.unt.edu/ark:/67531/metadc407836/
Functional Characterization of Mtnip/latd’s Biochemical and Biological Function
Access: Use of this item is restricted to the UNT Community.
Symbiotic nitrogen fixation occurs in plants harboring nitrogen-fixing bacteria within the plant tissue. The most widely studied association is between the legumes and rhizobia. In this relationship the plant (legumes) provides the bacteria (rhizobia) with reduced carbon derived from photosynthesis in exchange for reduced atmospheric nitrogen. This allows the plant to survive in soil, which is low in available of nitrogen. Rhizobia infect and enter plant root and reside in organs known as nodules. In the nodules the bacteria fix atmospheric nitrogen. The association between the legume, Medicago truncatula and the bacteria Sinorhizobium meliloti, has been studied in detail. Medicago mutants that have defects in nodulation help us understand the process of nitrogen fixation better. One such mutant is the Mtnip-1. Mtnip-1 plants respond to S. meliloti by producing abnormal nodules in which numerous aberrant infection threads are produced, with very rare rhizobial release into host plant cells. The mutant plant Mtnip-1 has an abnormal defense-like response in root nodules as well as defects in lateral root development. Three alleles of the Mtnip/latd mutants, Mtnip-1, Mtlatd and Mtnip-3 show different degrees of severity in their phenotype. Phylogenetic analysis showed that MtNIP/LATD encodes a protein belonging to the NRT1(PTR) family of nitrate, peptide, dicarboxylate and phytohprmone transporters. Experiments with Mtnip/latd mutants demonstrats a defective nitrate response associated with low (250 μM) external nitrate concentration rather than high (5 mM) nitrate concentration. This suggests that the mutants have defective nitrate transport. To test if MtNIP/LATD was a nitrate transporter, Xenopus laevis oocytes and Arabidopsis thaliana mutant plants Atchl1-5, defective in a major nitrate transporter AtNRT1.1(CHL1), were used as surrogate expression systems. Heterologous expression of MtNIP/LATD in X. laevis oocytes and Atchl1-5 mutant plants conferred on them the ability to take up nitrate from external media with high affinity, thus demonstrating that MtNIP/LATD was a high affinity nitrate transporter. Km for MtNIP/LATD was determined to be approximately160 μM in the X. laevis system and 113 μM in the Arabidopsis Atchl1-5 mutant lines thus supporting the previous observation of MtNIP/LATD being a high affinity nitrate transporter. X. laevis expressing the mutant Mtnip-1 and Mtlatd, were unable to transport nitrate. However X. laevis oocytes, expressing the less severe mutant allele Mtnip-3 were able to transport nitrate suggesting another role of the Mtnip/latd besides high affinity nitrate transport. Experimental evidence suggested that MtNIP/LATD might transport another substrate beside nitrate. MtNIP/LATD levels are regulated by phytohormones. Experiments performed with ABA (abscisic acid), IAA (indole acetic acid) and histidine as substrates in X. laevis system show that the MtNIP/LATD mRNA injected oocytes efflux IAA but do not transport histidine or ABA. When wild type A17 and mutant Mtnip-1 and Mtnip-3 plants, grown in the presence of different sources of nitrogen were screened in herbicide chlorate, a structural analog of nitrate, the A17 and Mtnip-3 mutant showed levels of susceptibility that was different from mutant Mtnip-1 lines. Evidence suggested that the amount of chlorate transported into the plants were regulated by the C:N status of the A17 and Mtnip-3 plants. This regulation was missing in the Mtnip-1 lines thus suggesting a sensor function of MtNIP/LATD gene. digital.library.unt.edu/ark:/67531/metadc407822/
The Validation of a Short-cycle Formative Assessment Observation Protocol for Science and Mathematics Instruction
Over the years, teachers, administrators, and policy makers have been concerned with optimizing learning for all students. The No Child Left Behind Act put an emphasis on summative assessments, which measure what students have learned. In contrast, formative assessment has been shown in many studies to improve student achievement and motivation because it is applied while students are learning. The purpose of this study was to investigate, for middle and high school mathematics and science instruction, the validity and reliability of a newly developed observation instrument called AssessToday, which is used in a single class period to assess a teacher’s use of short-cycle formative assessment. The content validity of the instrument was supported through an extensive literature review, feedback from experts in the field of formative assessment, and an examination of 98 classroom observations. For assessing reliability of the instrument, inter-rater reliability coefficients were calculated using data collected by trained observers who independently rated teachers during the same class period using three measures: percentage of agreement between raters, Cohen’s kappa, and Fleiss kappa. Cohen’s kappa (N = 36 pairs) ranged from .62 to 1.00 for all observer pairs with an average kappa of .75 for mathematics (n = 16 pairs) and .76 for science (n = 20 pairs). The recommended threshold for kappa is k = .70. An exploratory factor analysis was conducted on the observation data and the determined factors related to the theoretical framework established in the literature. The results affirmed that the instrument is a tool to be utilized in short-cycle formative assessment with middle and high school science and mathematics teachers. digital.library.unt.edu/ark:/67531/metadc407820/
A Comparison of Picture to Word Training and Word to Word Training on Native English Speaking College Students’ Acquisition of Italian Vocabulary
The current study assessed the effects of two teaching stimulus presentations, i.e. picture to word and word to word, used to teach second language vocabulary to college students. It also evaluated the emergence of untaught relations when picture to word and word to word were used separately as a teaching strategy. The findings showed picture to word training resulted in more untaught relations. Several aspects such time allotted for online quizzes, experimental and teaching arrangements and vocabulary complexity were suggested for future research. digital.library.unt.edu/ark:/67531/metadc407810/
Dynamic Adhesion and Self-cleaning Mechanisms of Gecko Setae and Spatulae
Geckos can freely climb on walls and ceilings against their body weight at speed of over 1ms-1. Switching between attachment and detachment seem simple and easy for geckos, without considering the surface to be dry or wet, smooth or rough, dirty or clean. In addition, gecko can shed dirt particles during use, keeping the adhesive pads clean. Mimicking this biological system can lead to a new class of dry adhesives for various applications. However, gecko’s unique dry self-cleaning mechanism remains unknown, which impedes the development of self-cleaning dry adhesives. In this dissertation we provide new evidence and self-cleaning mechanism to explain how gecko shed particles and keep its sticky feet clean. First we studied the dynamic enhancement observed between micro-sized particles and substrate under dry and wet conditions. The adhesion force of soft (polystyrene) and hard (SiO2 and Al2O3) micro-particles on soft (polystyrene) and hard (fused silica and sapphire) substrates was measured using an atomic force microscope (AFM) with retraction (z-piezo) speed ranging over 4 orders of magnitude. The adhesion is strongly enhanced by the dynamic effect. When the retraction speeds varies from 0.02 µm/s to 156 µm/s, the adhesion force increases by 10% ~ 50% in dry nitrogen while it increases by 15%~70% in humid air. A dynamic model was developed to explain this dynamic effect, which agrees well with the experimental results. Similar dynamic enhancement was also observed in aqueous solution. The influence of dynamic factors related to the adhesion enhancement, such as particle inertia, viscoelastic deformations and crack propagation, was discussed to understand the dynamic enhancement mechanisms. Although particles show dynamic enhancement, Gecko fabrillar hair shows a totally different trend. The pull off forces of a single gecko seta and spatula was tested by AFM under different pull-off velocities. The result shows that both the spatula and the seta have a rate independent adhesion response in normal retraction, which is quite different from micro-particles. Further research indicated the shape of the contact area was a key factor to the dynamic effect. In order to verify this hypothesis, artificial gecko spatula made of glass fibers was nanofabricated by a focus ion beam (FIB) and tested by AFM. These manmade spatulae also show a rate independent adhesion response. The dynamic adhesion of a single gecko seta and spatula were simulated with finite element analysis and the results also confirm the rate independent phenomena.. In conclusion, self-cleaning is induced by dynamic effect during gecko locomotion. The relative dynamic adhesion change between particles and seta makes it possible for gecko to shed the dirt particles while walking.Finally, the fatigue property of gecko seta was examined with the atomic force microscope under cyclic attachment/detachment process, mimicking gecko running. The adhesion force versus cycles has been tested and evaluated. Fatigue mechanism of gecko seta was also analyzed based on the experimental findings. digital.library.unt.edu/ark:/67531/metadc407812/
Exploring the Impacts of Fashion Blog Type and Message Type on Female Consumer Response Towards the Brand
The current study examines the influences of blog type and blog message type on consumers’ perceptions of brand credibility and brand similarity. Additionally, the study seeks to understand the interaction effects of blog type and message type on brand credibility and brand similarity and on consumer engagement with a blog. The findings reveal that message type, specifically product message, is an important consideration when marketers want to illustrate similarities between the brand and consumers. Additionally, it was found that product messages should be considered when encouraging consumer engagement with a blog. However, blog type did not have an effect on consumer perceptions of brand credibility and similarity or consumer engagement. digital.library.unt.edu/ark:/67531/metadc407834/
True Bromance: Representation of Masculinity and Heteronormative Dominance in the Bromantic Comedy
This project explores the representation of white, American masculinity within the Hollywood bromantic comedy cycle. By analyzing three interrelated components (close homosociality, infantilization, and relationship to patriarchy) of the model of masculinity perpetuated by this cycle of films, this study reveals the hegemonic motives therein. Despite the representation of a masculinity nervously questioning its position within the romantic comedy narrative and the broader patriarchal structure, the results of this representation are, ultimately, regressive and reactionary. Cultural gains made concerning gender, sexuality, and race are doubled back upon in a cycle of films that appeal to regressive modes of misogyny, homophobia, and racism still present in Hollywood filmmaking, and the hegemony of white, patriarchal heteronormativity is rigorously maintained. digital.library.unt.edu/ark:/67531/metadc407801/
Studies on High Potential Porphyrin-fullerene Supramolecular Dyads
Photoinduced electron transfer in self-assembled via axial coordination porphyrin-fullerene dyads is investigated. Fullerene functionalized with imidazole and fullerenes functionalized with pyridine are chosen as electron acceptors, while zinc pophyrin derivatives are utilized as electron donors. The electron withdrawing ability of halogen atoms make the porphyrin ring electrophilic, which explained the binding of (F20TPP)Zn with fullerene derivatives having the highest binding constant around 105M-1. Another important observation is that the fullerene imidazole binding to zinc pophyrin had higher stability than fullerene pyridine-porphyrin dyad. Computational DFT B3LYP-21G(*) calculations are used to study the geometric and electronic structures. The HOMO and LUMO was found to be located on the porphyrin and fullerene entities, respectively. Photoinduced electron transfer is investigated by the steady-state absorption and emission, differential pulse voltammetry, and nanosecond and femtosecond transient absorption studies. The measurements provided the same conclusion that the increasing number of the halogen atoms on the porphyrin ring leads to the higher binding of porphyrin-fullerene supramolecular dyads and efficient charge separation and charge recombination processes. digital.library.unt.edu/ark:/67531/metadc407825/
The Issues of Compliance and Interoperability in Integrating Heterogeneous Digital Resources: Lessons from the Texas History Portal
Paper for the 2005 IS&T Archiving Conference. This article discusses the issues of compliance and interoperability in integrating heterogeneous digital resources and lessons from the Texas History Portal. digital.library.unt.edu/ark:/67531/metadc406376/
No Dust in the Stacks: Creating a Customized Local Serials Collection on the Fly
Poster presented at the 2014 Charleston Annual Library Conference. This poster discusses creating a customized local serials collection on the fly. digital.library.unt.edu/ark:/67531/metadc406378/
Textbooks Weighing you Down? Check out our E-Readers
Article discussing a project by the UNT Libraries to purchase e-book readers for students purchasing digital textbooks. digital.library.unt.edu/ark:/67531/metadc406379/
Sample Core Journal List Spreadsheet
Spreadsheet document accompanying a poster for the 2014 Charleston Annual Library Conference. This spreadsheet is a sample of a core journal list for specialized or small academic libraries. digital.library.unt.edu/ark:/67531/metadc406375/
Managing Serials in a Large Digital Library: Case Study of the UNT Libraries Digital Collections
Article discussing a case study of the UNT Libraries digital collections and managing serials in a large digital library. digital.library.unt.edu/ark:/67531/metadc406384/
Mentoring to Grow Library Leaders
Article discussing mentoring and growing library leaders. digital.library.unt.edu/ark:/67531/metadc406380/
"Blow the Curtain Open": How Gene Hall and Leon Breeden Advanced the Legitimacy of Jazz in Music Education [Presentation Notes]
Notes accompanying a presentation for the Jazz Education Network Fifth Annual Conference. These notes and the presentation discuss how Gene Hall and Leon Breeden advanced the legitimacy of jazz in music education. digital.library.unt.edu/ark:/67531/metadc406359/
"Blow the Curtain Open": How Gene Hall and Leon Breeden Advanced the Legitimacy of Jazz in Music Education [Presentation]
Presentation for the Jazz Education Network Fifth Annual Conference. This presentation discusses how Gene Hall and Leon Breeden advanced the legitimacy of jazz in music education. digital.library.unt.edu/ark:/67531/metadc406353/
UNT Libraries Strategic Plan Priorities FY 2014-2017: Key prospective Goal Areas for the UNT Libraries
This report summarizes key strategic priorities for the UNT Libraries in the FY 2014-2017 period, and will inform planning activities during this time. This document should be read in close conjunction with other associated strategic planning documents of the UNT Libraries, including the following: 2014 Strategic Plan Alignment Map of UNT Libraries and Academic Affairs, UNT Libraries Strategic Plan 2011-2015, and UNT Press Strategic Plan 2014-2019. This document lays out the primary directions that the UNT Libraries will undertake during the coming four years. It builds on previous work and accomplishments during the 2011-2014 period, and serves as a transitional planning guide for moving beyond the 2011-2015 strategic plan. The most important priority for the next three years will be the first one listed: improving library resources. Without adequate resources, it is unlikely that progress will be made on the other priorities. digital.library.unt.edu/ark:/67531/metadc406348/
How Descriptive Metadata Changes in the UNT Libraries' Collection: A Case Study
Paper describing the results of initial research to evaluate general information about how records change in a digital library, using the UNT digital collections as a sample set. The analysis looked at several key concepts including the number of records that have been edited, the number of edits per record, the number of editors per record, the amount of change in file size and in completeness (i.e., values in required fields), and changes in access to digital objects. digital.library.unt.edu/ark:/67531/metadc406345/
Ensuring Long-Term Access to Electronic Theses and Dissertations: Local vs. Global Lifecycle Management
Presentation for the 2014 Texas Library Association (TLA) Annual Conference. This presentation discusses ensuring long-term access to electronic theses and dissertations and local versus global lifecycle management. digital.library.unt.edu/ark:/67531/metadc406366/
Balancing Scholarly Activities, Primary Assignments and Service to the Community
Presentation for the University of North Texas (UNT) Libraries as part of the career development program. This presentation discusses getting started on a research project and balancing scholarly activities, primary assignments, and service to the community. digital.library.unt.edu/ark:/67531/metadc406368/
UNT's Theses and Dissertations Retrospective Digitization Project
Poster presented at the 2014 United States (U.S) Electronic Theses and Dissertations (ETDs) Annual Conference. This poster discusses the University of North Texas' (UNTs) retrospective digitization project of theses and dissertations. digital.library.unt.edu/ark:/67531/metadc406331/
A REST API for Library Data
Poster presented at the 2014 International Conference on Dublin Core and Metadata Applications. This poster discusses a library catalog REST API framework. digital.library.unt.edu/ark:/67531/metadc406332/
Data Management in the UNT Digital Library
Presentation for the Texas Digital Library (TDL) Data Management Workgroup. This presentation discusses data management in the University of North Texas (UNT) Digital Library. digital.library.unt.edu/ark:/67531/metadc406361/
UNT Scholarly Works
Presentation for the University of North Texas (UNT) School of Library and Information Science (SLIS) 5740 course, Introduction to Digital Libraries. This presentation discusses the UNT Scholarly Works institutional repository and gives a brief history, submissions and workflow processes, copyright and publisher considerations, and open access issues. digital.library.unt.edu/ark:/67531/metadc406371/
When Fulltext Searching Isn't Enough: Text Encoding for Manuscripts and Other Special Collections Materials
Presentation for the Cross Timbers Library Collaborative (CTLC) Special Collections Affinity Group Fall 2014 Meeting. This presentation discusses text encoding for manuscripts and other special collections materials. digital.library.unt.edu/ark:/67531/metadc406356/
Using the Power of Excel... To help with cutting a budget
Presentation for an Association for Library Collections & Technical Services (ALCTS) webinar. This presentation discusses using Excel to help cut budgets. digital.library.unt.edu/ark:/67531/metadc406351/
Open Access and ETDs
Poster presented at the 2014 United States (U.S) Electronic Theses and Dissertations (ETDs) Annual Conference. This poster discusses open access and ETDs. digital.library.unt.edu/ark:/67531/metadc406342/
Lexicon of Jazz Invective: Hurling Insults Across a Century with Big Data [presentation]
Presentation for the Texas Music Library Association Fall 2014 Meeting. This presentation discusses the lexicon of jazz invective and hurling insults across a century with big data. digital.library.unt.edu/ark:/67531/metadc406370/
Lexicon of Jazz Invective: Hurling Insults Across a Century with Big Data [presentation notes]
Notes accompanying a presentation for the Texas Music Library Association Fall 2014 Meeting. These notes and the presentation discuss the lexicon of jazz invective and hurling insults across a century with big data. digital.library.unt.edu/ark:/67531/metadc406365/
How Descriptive Metadata Changes in the UNT Libraries' Collection: A Case Study [Presentation]
Presentation for the 2014 DCMI International Conference on Dublin Core and Metadata Applications. This presentation discusses a case study of how descriptive metadata changes in the UNT Libraries' collections. digital.library.unt.edu/ark:/67531/metadc406363/
ASIS&T Special Interest Groups (SIGs): New Member/First Conference Brunch 2012
Presentation for the 2012 American Society for Information Science and Technology (ASIS&T) Annual Meeting. This presentation introduces new members and conference attendees to the Special Interest Group, International Information Issues (SIG-III). digital.library.unt.edu/ark:/67531/metadc406369/
A For-Fee Publishing Service for the Local Community [Presentation]
Presentation for Amigos Library Services online conference, "Libraries, Authors, and Publishing." This presentation discusses a for-fee publishing service for the local community. digital.library.unt.edu/ark:/67531/metadc406354/