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 Collection: UNT Theses and Dissertations
Ultrafast Laser Sampling of a Plant Tissue and ion Conductivity Measurement for Investigation of Light Stress Generation Mechanisms

Ultrafast Laser Sampling of a Plant Tissue and ion Conductivity Measurement for Investigation of Light Stress Generation Mechanisms

Date: August 2010
Creator: Abtahi, Seyed Ali
Description: In this study we applied ultra-short laser pulses on a biological sample (Arabidopsis), in order to cut it precisely in a square pattern and subsequently use it for studying stress generation mechanisms. For this purpose, we utilized femtosecond laser pulses at 100 fs pulse width and 80 MHz repetition rate. We took two processing parameters into consideration such as laser power, laser exposure time which is related to the stage speed. Therefore, we were able to find the laser optimum conditions for ablation of biological tissues. The mutant and wildtype (control) obtained from laser cutting with a size of 500 µm × 500 µm were directly transferred (in-situ with laser cutting) into a microfabricated chamber containing ~500 nanoliters deionized water for measuring ion conductivity. The ion conductivity is a signature of cell-death mechanisms caused by various stresses. A light with intensity of 100 µmol was exposed to the samples for 2 hours and 20 minutes as a source of stress. A quantitative electrical analysis with high accuracy was assured by utilizing a microchamber, which enables a measurement in nanoliter volume. We measured the impedance which is reciprocal of conductivity using a lock-in amplifier and a precise current source at frequency ...
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Corporate Christians and Terrible Turks: Economics, Aesthetics, and the Representation of Empire in the Early British Travel Narrative, 1630 - 1780

Corporate Christians and Terrible Turks: Economics, Aesthetics, and the Representation of Empire in the Early British Travel Narrative, 1630 - 1780

Date: December 2003
Creator: Abunasser, Rima Jamil
Description: This dissertation examines the evolution of the early English travel narrative as it relates to the development and application of mercantilist economic practices, theories of aesthetic representation, and discourses of gender and narrative authority. I attempt to redress an imbalance in critical work on pre-colonialism and colonialism, which has tended to focus either on the Renaissance, as exemplified by the works of critics such as Stephen Greenblatt and John Gillies, or on the later eighteenth and early nineteenth centuries, as in the work of scholars such as Srinivas Aravamudan and Edward Said. This critical gap has left early travel narratives by Sir Francis Moore, Jonathan Harris, Penelope Aubin, and others largely neglected. These early writers, I argue, adapted the conventions of the travel narrative while relying on the authority of contemporary commercial practices. The early English travelers modified contemporary conventions of aesthetic representation by formulating their descriptions of non-European cultures in terms of the economic and political conventions and rivalries of the early eighteenth century. Early English travel literature, I demonstrate, functioned as a politically motivated medium that served both as a marker of authenticity, justifying the colonial and imperial ventures that would flourish in the nineteenth century, and as ...
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The Meaning of Elder Abuse

The Meaning of Elder Abuse

Access: Use of this item is restricted to the UNT Community.
Date: May 2000
Creator: Achilli, Raye
Description: Elder abuse first received national attention in 1980, as the subject of a congressional investigation. Now, 20 years later, establishing successful strategies of identification, subsequent intervention, and prevention of abuse is of paramount importance; but progress toward this goal is hindered by lack of consensus as to the definition of elder abuse, and the use of vague, confusing, and sometimes contradictory terms in its discussion. In this paper, both social research and professional approaches and legal approaches to the definition of elder abuse are surveyed, as are definitions formulated for the National Elder Abuse Incidence Study conducted by the National Center on Elder Abuse. The continuing need for a universal or standard definition is emphasized.
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Haves, Halves, and Have-Nots: School Libraries and Student Achievement in California

Haves, Halves, and Have-Nots: School Libraries and Student Achievement in California

Date: December 2008
Creator: Achterman, Douglas L.
Description: This descriptive, non-experimental study examines the strength of the relationship between California school library media programs and student achievement, using data from California criterion-referenced state-wide tests, publically available school and community demographic data, and a state survey of school library programs. Results indicate a substantial discrepancy in library staffing levels from the elementary grades through the high schools. Nevertheless, statistically significant correlations were found between certificated staffing levels and student achievement at each grade. Significant correlations persisted at the elementary and middle school when controlling for five of six school and community variables, and at the high school when controlling for all six of those variables. Bivariate correlations between total staffing and student achievement were significant at both the middle school and high school level when controlling for all school and community variables. Generally, the strength of the correlations between both certificated and total staffing tended to increase with grade level; at the high school level, correlations were among the strongest reported in any statewide study to date. There was a significant positive relationship between a majority of the 21 library services regularly provided and student achievement at all levels. Total library services were significantly related to student achievement at ...
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The Value of Filmstrips in the Third Grade

The Value of Filmstrips in the Third Grade

Date: 1950
Creator: Adair, Elva Gaynelle
Description: The purpose of this study is to determine the possible influence of the use of filmstrip material upon a group of third-grade pupils as compared with another group of third-grade pupils not using filmstrip materials.
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Joint Schemes for Physical Layer Security and Error Correction

Joint Schemes for Physical Layer Security and Error Correction

Date: August 2011
Creator: Adamo, Oluwayomi Bamidele
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 ...
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VLSI Architecture and FPGA Prototyping of a Secure Digital Camera for Biometric Application

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

Date: August 2006
Creator: Adamo, Oluwayomi Bamidele
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 ...
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A Differential Study of Reasons Why Students Drop Out of School as Related to Actual Dropout-preventive Practices of a Metropolitan School District

A Differential Study of Reasons Why Students Drop Out of School as Related to Actual Dropout-preventive Practices of a Metropolitan School District

Date: August 1972
Creator: Adams, Ambrose Davidson, 1936-
Description: The problem of this study was the differentiation of high schools in a metropolitan school district from the standpoint of the measures taken to prevent student dropouts.
Contributing Partner: UNT Libraries
Solutions of the Equations of Radiative Transfer by an Invariant Imbedding Approach

Solutions of the Equations of Radiative Transfer by an Invariant Imbedding Approach

Date: January 1969
Creator: Adams, Charles N.
Description: This thesis is a study of the solutions of the equations of radiative transfer by an invariant imbedding approach.
Contributing Partner: UNT Libraries
The Development of Dramatic Exposition in the Plays of George Farquhar

The Development of Dramatic Exposition in the Plays of George Farquhar

Date: August 1965
Creator: Adams, Dale Talmadge
Description: The purpose of this thesis is to make further contribution in filling the gap in detailed analyses of George Farquhar's plays.
Contributing Partner: UNT Libraries