UNT Libraries - 23,070 Matching Results

Search Results

Megadrought and Megadeath in 16th Century Mexico

Description: The native population collapse in 16th century Mexico was a demographic catastrophe with one of the highest death rates in history. Recently developed tree-ring evidence has allowed the levels of precipitation to be reconstructed for north central Mexico, adding to the growing body of epidemiologic evidence and indicating that the 1545 and 1576 epidemics of cocoliztli (Nahuatl for "pest") were indigenous hemorrhagic fevers transmitted by rodent hosts and aggravated by extreme drought conditions.
Date: 2002
Creator: Acuna-Soto, Rodolfo; Stahle, David W.; Cleaveland, Malcolm K. & Therrell, Matthew D.

A Working Bibliography on the Art of Drawing

Description: This working bibliography of 835 publications on the art of drawing is presented in five categories: Educational and Psychological, Historical, "How-to," Technical, and Techniques of Teaching Drawing. The latter category is annotated, offering a synthesis of the areas of art education and drawing. This bibliography is designed for scholars, artists, and teachers as well as students of the many facets of drawing.
Date: August 1974
Creator: Adair, Rosalind Emily

Vibrational Spectra and Potential Function of Tetrachlorocyclopropene

Description: The laser Raman spectra of tetrachlorocyclopropene in the liquid and solid phases have been recorded and vibrational assignments are presented. These results along with root mean squared vibrational amplitudes from electron diffraction data have been employed in a normal coordinate analysis in which a 19 parameter potential function is refined. This potential function, originally expressed in terms of compliance constants, is then used to derive the corresponding conventional and relaxed force constants.
Date: August 1981
Creator: Adame, I. Ernesto (Ignacio Ernesto)

Joint Schemes for Physical Layer Security and Error Correction

Description: The major challenges facing resource constraint wireless devices are error resilience, security and speed. Three joint schemes are presented in this research which could be broadly divided into error correction based and cipher based. The error correction based ciphers take advantage of the properties of LDPC codes and Nordstrom Robinson code. A cipher-based cryptosystem is also presented in this research. The complexity of this scheme is reduced compared to conventional schemes. The securities of the ciphers are analyzed against known-plaintext and chosen-plaintext attacks and are found to be secure. Randomization test was also conducted on these schemes and the results are presented. For the proof of concept, the schemes were implemented in software and hardware and these shows a reduction in hardware usage compared to conventional schemes. As a result, joint schemes for error correction and security provide security to the physical layer of wireless communication systems, a layer in the protocol stack where currently little or no security is implemented. In this physical layer security approach, the properties of powerful error correcting codes are exploited to deliver reliability to the intended parties, high security against eavesdroppers and efficiency in communication system. The notion of a highly secure and reliable physical layer has the potential to significantly change how communication system designers and users think of the physical layer since the error control codes employed in this work will have the dual roles of both reliability and security.
Date: August 2011
Creator: Adamo, Oluwayomi Bamidele

VLSI Architecture and FPGA Prototyping of a Secure Digital Camera for Biometric Application

Description: This thesis presents a secure digital camera (SDC) that inserts biometric data into images found in forms of identification such as the newly proposed electronic passport. However, putting biometric data in passports makes the data vulnerable for theft, causing privacy related issues. An effective solution to combating unauthorized access such as skimming (obtaining data from the passport's owner who did not willingly submit the data) or eavesdropping (intercepting information as it moves from the chip to the reader) could be judicious use of watermarking and encryption at the source end of the biometric process in hardware like digital camera or scanners etc. To address such issues, a novel approach and its architecture in the framework of a digital camera, conceptualized as an SDC is presented. The SDC inserts biometric data into passport image with the aid of watermarking and encryption processes. The VLSI (very large scale integration) architecture of the functional units of the SDC such as watermarking and encryption unit is presented. The result of the hardware implementation of Rijndael advanced encryption standard (AES) and a discrete cosine transform (DCT) based visible and invisible watermarking algorithm is presented. The prototype chip can carry out simultaneous encryption and watermarking, which to our knowledge is the first of its kind. The encryption unit has a throughput of 500 Mbit/s and the visible and invisible watermarking unit has a max frequency of 96.31 MHz and 256 MHz respectively.
Date: August 2006
Creator: Adamo, Oluwayomi Bamidele

Someone to Talk to: Conversations Between Friends in a Junior High Lunch Room

Description: Quantitative studies dominate early adolescence research, a field which also lacks an understanding of communication behaviors between early adolescents. This study uses the qualitative methods of participant observation and informal interviews to observe conversations between girls in a junior high lunch room. Friendship characteristics and group socialization are discussed as they emerged from the field data. First, friendship hierarchies (best friend, close friend, and friend) may be adult-imposed structures. Hierarchies are not prominent in the minds of friends as they relate to each other in daily conversation. Second, friendship groups serve to socialize early adolescent girls.
Date: December 1990
Creator: Adams, Brenda Inglis

Female Inheritors of Hawthorne's New England Literary Tradition

Description: Nineteenth-century women were a mainstay in the New England literary tradition, both as readers and authors. Indeed, women were a large part of a growing reading public, a public that distanced itself from Puritanism and developed an appetite for novels and magazine short stories. It was a culture that survived in spite of patriarchal domination of the female in social and literary status. This dissertation is a study of selected works from Nathaniel Hawthorne, Sarah Orne Jewett, and Mary E. Wilkins Freeman that show their fiction as a protest against a patriarchal society. The premise of this study is based on analyzing these works from a protest (not necessarily a feminist) view, which leads to these conclusions: rejection of the male suitor and of marriage was a protest against patriarchal institutions that purposely restricted females from realizing their potential. Furthermore, it is often the case that industrialism and abuses of male authority in selected works by Jewett and Freeman are symbols of male-driven forces that oppose the autonomy of the female. Thus my argument is that protest fiction of the nineteenth century quietly promulgates an agenda of independence for the female. It is an agenda that encourages the woman to operate beyond standard stereotypes furthered by patriarchal attitudes. I assert that Jewett and Freeman are, in fact, inheritors of Hawthorne's literary tradition, which spawned the first fully-developed, independent American heroine: Hester Prynne.
Date: August 1994
Creator: Adams, Dana W. (Dana Wills)

Base Effects on the Thermal Decomposition of Sec-butyllithium Solutions

Description: The pyrolysis of sec-butyllithium in solution was studied in an attempt to understand the loss of stereo-specificity and the atypical kinetics that have been reported. Additionally, the effect of added lithium alkoxides was studied to determine their effects on the highly reactive sec-butyllithium substrate.
Date: June 1966
Creator: Adams, George Michael

A Study of the Bacterial Flora of Food Utensils in Hardin College Cafeteria and Twenty-Five Eating Establishments in Wichita Falls, Texas

Description: The problem of this thesis consists primarily of a bacteriological survey of the eating utensils of Hardin College Cafeteria and twenty-five other eating establishments in the city of Wichita Falls, Texas. This investigation was made primarily with reference to a determination of the possible presence of typhoid and related organisms, and secondarily to an investigation of the actual presence of those bacterial organisms associated with the more common outbreaks of food poisoning.
Date: 1949
Creator: Adams, Isaac Newton

The Relationship Between Supplemental Instruction Leader Learning Style and Study Session Design

Description: The purpose of this qualitative study was to examine the learning styles of supplemental instruction leaders at a large, public university during the fall 2010 semester and determine whether or not their personal learning styles influenced the way they designed and developed out-of-class study sessions. The total population of supplemental instruction leaders was 37, of which 24 were eligible to participate in the study. Of the 24 eligible supplemental instruction leaders, 20 completed the entire study. Participants in the study included nine male and 11 female supplemental instruction leaders with a median age of 22.25 years-old. Seventeen participants indicated their classification as senior, two as junior, and one as sophomore. Of the participants, 16 indicated white as a race or ethnicity, one indicated Asian, two indicated African American, and one indicated both American Indian/Alaska Native and white. Supplemental instruction leader learning style was assessed using the Kolb Learning Style Inventory. Leaders were then interviewed, and their study sessions were analyzed. Through triangulation of data from learning style, interviews and actual study session documents, four major themes emerged. The four themes were: 1) incorporation of personal experience into study session design, 2) the sense of impact on student learning, 3) a feeling of the need to incorporate varied activities into study session design, and 4) the concept that students must take ownership over their own learning. No consistent pattern emerged among the themes; however, the results attributed out-of-class study session design to both the incorporation of personal learning style preferences as identified through the Kolb Learning Style Inventory and training conducted by the institution. Implications for future research include the need for continued research addressing how and if supplemental instruction leader learning style influences out-of-class study session design. Also, as institutions of higher education seek to expand academic support services to ...
Date: May 2011
Creator: Adams, Joshua

Integrating Selective Herbicide and Native Plant Restoration to Control Alternanthera philoxeroides (Alligator Weed)

Description: Exotic invasive aquatic weeds such as alligator weed (Alternanthera philoxeroides) threaten native ecosystems by interfering with native plant communities, disrupting hydrology, and diminishing water quality. Development of new tools to combat invaders is important for the well being of these sensitive areas. Integrated pest management offers managers an approach that combines multiple control methods for better control than any one method used exclusively. In a greenhouse and field study, we tested the effects of selective herbicide application frequency, native competitor plant introduction, and their integration on alligator weed. In the greenhouse study, alligator weed shoot, root, and total biomass were reduced with one herbicide application, and further reduced with two. Alligator weed cumulative stem length and shoot/root ratio was only reduced after two applications. In the greenhouse, introduction of competitors did not affect alligator weed biomass, but did affect shoot/root ratio. The interaction of competitor introduction and herbicide did not significantly influence alligator weed growth in the greenhouse study. In the field, alligator weed cover was reduced after one herbicide application, but not significantly more after a second. Introduction of competitor species had no effect on alligator weed cover, nor did the interaction of competitor species and herbicide application. This study demonstrates that triclopyr amine herbicide can reduce alligator weed biomass and cover, and that two applications are more effective than one. To integrate selective herbicides and native plant introduction successfully for alligator weed control, more research is needed on the influence competition can potentially have on alligator weed growth, and the timing of herbicide application and subsequent introduction of plants.
Date: December 2011
Creator: Adams, Justin

Music in the Oklahoma Territory, 1889-1907

Description: This study is a history of the musical activities in the Territory of Oklahoma from 1889 to 1907. Material for this dissertation was gathered from newspapers, books, periodicals, letters, sheet music, concert programs, college catalogues, church records, and photographs. Oklahoma City and Guthrie, the most important cities of the territory, provide the locals for the greater part of the study. These two communities reflect the cultural tastes and activities of the entire territory.
Date: August 1979
Creator: Adams, K. Gary