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

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

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 …
Date: August 2010
Creator: Abtahi, Seyed Ali
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Reducing Greenhouse Gas Emissions in Washington State Government (open access)

Reducing Greenhouse Gas Emissions in Washington State Government

This report summarizes the total GHG emission from all state agencies for 2005, 2008, and 2009. It examines actions already taken by agencies to reduce emissions and outlines key next steps for agencies to take to develop emission reduction strategies.
Date: December 2010
Creator: Adelsman, Hedia & Ekrem, Joanna
Object Type: Text
System: The UNT Digital Library
Photoactivatable Quantum Dots in Super-Resolution Microscopy of Muscle (open access)

Photoactivatable Quantum Dots in Super-Resolution Microscopy of Muscle

Super-resolution 3D imaging was achieved using newly synthesized photoactivatable quantum dot (PAQ dot) probes. Quantum dots were modified with a novel quencher system to make them photoactivatable. The unique properties of these PAQ dots enable single-fluorophore localization in three dimensions using a confocal microscopy optical sectioning method. Myosin and tropomyosin of rabbit myofibrilar bundles were specifically labeled with the newly synthesized PAQ dot. A sufficient number of single quantum dots were photoactivated, localized and reduced to their centroid and then reconstructed to a super-resolution image. The acquired super-resolution image shows a lateral and an axial sub-diffraction resolution and demonstrates ultrafine striations with widths less than 70 nm that are not evident by conventional confocal microscopy. The striations appear to be related to nebulin thin filament binding protein. This newly developed imaging system is cutting edge for its high resolution and localization as well its simplicity and convenience.
Date: December 2010
Creator: Akel, Amal
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Determination of the Optimal Number of Strata for Bias Reduction in Propensity Score Matching. (open access)

Determination of the Optimal Number of Strata for Bias Reduction in Propensity Score Matching.

Previous research implementing stratification on the propensity score has generally relied on using five strata, based on prior theoretical groundwork and minimal empirical evidence as to the suitability of quintiles to adequately reduce bias in all cases and across all sample sizes. This study investigates bias reduction across varying number of strata and sample sizes via a large-scale simulation to determine the adequacy of quintiles for bias reduction under all conditions. Sample sizes ranged from 100 to 50,000 and strata from 3 to 20. Both the percentage of bias reduction and the standardized selection bias were examined. The results show that while the particular covariates in the simulation met certain criteria with five strata that greater bias reduction could be achieved by increasing the number of strata, especially with larger sample sizes. Simulation code written in R is included.
Date: May 2010
Creator: Akers, Allen
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Routine Leisure Activities and Adolescent Marijuana Use: Moderating Effects of Family Structure (open access)

Routine Leisure Activities and Adolescent Marijuana Use: Moderating Effects of Family Structure

How adolescents spend their time is a crucial predictor of their engagement in delinquency. Activities with peers away from direct supervision of adults are of concern as more opportunities and motivation to use marijuana exist in such situations. However, adolescents may vary in their propensity to use marijuana when faced the opportunity. Especially adolescents living with a single parent may have a higher propensity compared to those from two-parent households to use marijuana due to reduced parental monitoring and increased peer attachment. This thesis investigates the moderating effects of family structure on the routine leisure activities and adolescent marijuana use relationship, using data from Monitoring the Future Study 2007, 12th Grade Survey. The results provide partial support for the moderating effects.
Date: May 2010
Creator: Aksu, Gokhan
Object Type: Thesis or Dissertation
System: The UNT Digital Library
L'emploi variable des signes diacritiques dans le français tchaté : une étude variationniste en temps apparent . (open access)

L'emploi variable des signes diacritiques dans le français tchaté : une étude variationniste en temps apparent .

After providing an historical overview of the French spelling system and orthographic variation, this study analyzes selected internal (i.e., linguistic) factors and one external (i.e., social) factor that can influence the use of diacritics in online French-language chat sessions. From a corpus of synchronous computer-mediated communication, 3,855 tokens of graphemes capable of bearing diacritics were coded with the following scheme: Letter, Diacritic, Grapheme (i.e., Letter and Diacritic combined), Date of Participation, and Age Group of Participant. A multivariate (VARBRUL) analysis determined that Grapheme exerts the most influence on variation.
Date: May 2010
Creator: Al-Rashdan, Omar
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Faculty Members' Readiness for E-learning in the College of Basic Education in Kuwait (open access)

Faculty Members' Readiness for E-learning in the College of Basic Education in Kuwait

E-learning exposes students and instructors to different learning models such as constructivism rather than the traditional learning. E-learning as a part of today's technology has proven that it is appropriate for most students' mentalities and is a mind tool which promotes different learning models, such as problem solving strategy, collaborative learning, and critical thinking. The Public Authority for Applied Education and Training (PAAET) in Kuwait consists of more than 10 academic colleges with a total number of 120 faculty members. The College of Basic Education (CBE) is one of them. The implementation of e-learning at the College of Basic Education requires that all the learning community members, instructors and students, understand that an e-learning course is like a learning community with the privilege of sharing knowledge, opinions, experiences related to class subject, and productive outcomes that are beneficial to this learning community. This study indentified the statistically significant differences in demographic characteristics of e-learning adopters and non-adopters among faculty members at CBE, examining faculty members' attitudes and skills toward e-learning readiness. The study will explore perceived barriers that face e-learning at CBE. Applying the Rogers diffusion of innovation theory, the influence of 4 factors was examined regarding faculty readiness for …
Date: August 2010
Creator: Alajmi, Mohammed
Object Type: Thesis or Dissertation
System: The UNT Digital Library

"Good" Digital Collections

This Tech Talks presentation covers the principles that apply to "good" digital collections and analyzes how objects, metadata, and the user interface together create the users' experience of a collection.
Date: January 27, 2010
Creator: Alemneh, Daniel Gelaw
Object Type: Presentation
System: The UNT Digital Library
Exploration of Adoption of Preservation Metadata in Cultural Heritage Institutions (open access)

Exploration of Adoption of Preservation Metadata in Cultural Heritage Institutions

Paper presented at the 2010 ASIS&T Annual Meeting. This paper discusses preservation metadata and its role in the challenges of long-term access.
Date: 2010
Creator: Alemneh, Daniel Gelaw & Hastings, Samantha Kelly
Object Type: Paper
System: The UNT Digital Library

Integration of ETD into Topical Digital Library Collections: Facilitating ETD Use and Reuse

Poster presented at the 2010 Texas Electronic Theses and Dissertations (ETDs) Conference. This poster discusses the integration of ETDs into topical digital library collections and facilitating ETD use and reuse.
Date: 2010
Creator: Alemneh, Daniel Gelaw & Phillips, Mark Edward
Object Type: Poster
System: The UNT Digital Library

Texas Digital Library (TDL) Metadata Working Group Update

This presentation provides an update on three projects the Texas Digital Library Metadata Working Group (TDL-MWG) is working on. These include designing a metadata information website, creating best practices for images and datasets, and creating metadata courses for Texas Digital Library (TDL) training.
Date: 2010
Creator: Alemneh, Daniel Gelaw; Davis, Jee-Hyun; Thomale, Jason; Chen, Mingyu; Mercer, Holly; Hazzard, Jeanne et al.
Object Type: Presentation
System: The UNT Digital Library
Family Sex Talk: Analyzing the Influence of Family Communication Patterns on Parent and Late Adolescent's Sex Conversations (open access)

Family Sex Talk: Analyzing the Influence of Family Communication Patterns on Parent and Late Adolescent's Sex Conversations

Family communication has the potential to affect a variety of youth behavioral outcomes including adolescent sexual risk behavior. Within chapter 1, I present past literature on adolescent sexual risk behaviors, family communication patterns, and the gaps associated with those areas. In chapter 2, I review previous literature on adolescent sexual risk behavior, parent-child communication and family communication patterns. In chapter 3, I present the method which includes a description of the participants, procedures, measures, and data analysis used. In Chapter 4, I present the results of the study. According to the results of the study, father-child communication is not a better predictor of adolescent sexual risk behavior. A higher quantity of parent-child communication does not lead to less adolescent sexual risk behavior. Participants with a pluralistic family type do significantly differ from laissez-faire and protective family types in regards to levels of parent-child communication. Participants with a consensual family type do have significantly higher levels of parent-child communication in comparison to laissez-faire family types, but not protective family types. Finally, in chapter 5, I present the discussion with a review of previous research (consistent or inconsistent with the current findings), limitations and conclusions for the current study.
Date: August 2010
Creator: Allen, Evette L.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
The Works for Clarinet Commissioned by the Concours International d'Exécution Musicale de Genève: A Critical Survey and Performance Guide (open access)

The Works for Clarinet Commissioned by the Concours International d'Exécution Musicale de Genève: A Critical Survey and Performance Guide

Beginning in 1939, the Concours International d'Exécution Musicale de Genève (CIEM; Geneva International Music Competition) is unique among international music competitions in its multidisciplinary approach. To date, fifteen works have been commissioned for clarinet for the years in which the clarinet was involved. The most well-known of these works is the unaccompanied work by Heinrich Sutermeister, Capriccio for Solo Clarinet in A, written in 1946 for the 1947 competition. This work is a staple in the unaccompanied clarinet repertoire. However, the other fourteen works commissioned for the competition are little known and to date no document has been prepared that examines each of these works in the context of the competition and clarinet literature. While perhaps less notable, works were also commissioned for a sight reading portion of the competition for many of the years in which the clarinet was a discipline chosen for the competition, two of which were published. These works are examined as well. This survey provides a critical, analytical, historical, performance-related and biographical review of the published and unpublished works commissioned for the clarinet by CIEM. The composers, competitors and the significance of these works and winners in the clarinet literature and history are included. A …
Date: August 2010
Creator: Allgeier, Anthony Joseph, III
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Effects of Suspended Multi-Walled Carbon Nanotubes on Daphnid Growth and Reproduction (open access)

Effects of Suspended Multi-Walled Carbon Nanotubes on Daphnid Growth and Reproduction

Multi-walled carbon nanotube aggregates can be suspended in the aqueous phase by natural organic matter. These aggregates are ingested by filter feeding zooplankton. Ingested aggregates result in decreased growth and decreased reproduction. These effects may be caused by reduction in energy input from normal feeding behavior. pH alters natural organic matter structure through changes in electrostatic repulsion. Altered natural organic matter structure changes multi-walled carbon nanotube aggregate size. This size variation with variation in pH is significant, but not large enough a change in size to alter toxicity, as the aggregate size range remains well within the particle size selection of the organisms.
Date: May 2010
Creator: Alloy, Matthew Michael
Object Type: Thesis or Dissertation
System: The UNT Digital Library
The Hexagon, Volume 101, Number 1, Spring 2010 (open access)

The Hexagon, Volume 101, Number 1, Spring 2010

Quarterly publication of the Alpha Chi Sigma chemistry fraternity containing articles related to chemistry research and the activities of the organization, including local chapters and groups.
Date: Spring 2010
Creator: Alpha Chi Sigma
Object Type: Journal/Magazine/Newsletter
System: The UNT Digital Library
The Hexagon, Volume 101, Number 2, Summer 2010 (open access)

The Hexagon, Volume 101, Number 2, Summer 2010

Quarterly publication of the Alpha Chi Sigma chemistry fraternity containing articles related to chemistry research and the activities of the organization, including local chapters and groups.
Date: Summer 2010
Creator: Alpha Chi Sigma
Object Type: Journal/Magazine/Newsletter
System: The UNT Digital Library
The Hexagon, Volume 101, Number 3, Fall 2010 (open access)

The Hexagon, Volume 101, Number 3, Fall 2010

Quarterly publication of the Alpha Chi Sigma chemistry fraternity containing articles related to chemistry research and the activities of the organization, including local chapters and groups.
Date: Autumn 2010
Creator: Alpha Chi Sigma
Object Type: Journal/Magazine/Newsletter
System: The UNT Digital Library
The Hexagon, Volume 101, Number 4, Winter 2010 (open access)

The Hexagon, Volume 101, Number 4, Winter 2010

Quarterly publication of the Alpha Chi Sigma chemistry fraternity containing articles related to chemistry research and the activities of the organization, including local chapters and groups.
Date: Winter 2010
Creator: Alpha Chi Sigma
Object Type: Journal/Magazine/Newsletter
System: The UNT Digital Library
"The Dying Mother:" Historical Citations of Mary Goffe's Seventeenth-Century Near-Death Apparition (open access)

"The Dying Mother:" Historical Citations of Mary Goffe's Seventeenth-Century Near-Death Apparition

Abstract: Traditionally, certain cases have been of particular importance to students of near-death phenomena. Such cases are more than mere examples or research data; they are resources that are generally used to defend particular theoretical ideas, such as the projection of the spirit or of some subtle body from the physical body around the time of death. One such case was that of Mary Goffe, a seventeenth-century apparition of a dying woman that Richard Baxter reported in his book "The Certainty of the Worlds of Spirits" (1691). This paper includes a reprint of the original case report and a discussion of how later writers used the case to defend the idea that something may leave the body during near-death states.
Date: Autumn 2010
Creator: Alvarado, Carlos S.
Object Type: Article
System: The UNT Digital Library
Online Resources for the History of Out-of-Body Experiences and Death-Related Phenomena (open access)

Online Resources for the History of Out-of-Body Experiences and Death-Related Phenomena

Abstract: Google Books is a digital library covering out of print publications about a variety of topics, among them materials relevant for a history of discussions, observations, and collections of cases of out-of-body experiences and death-related phenomena such as near-death experiences, deathbed visions, and apparitions. In this article, I provide examples of copyright-free and cost-free sources from Google Books that investigators of near-death and related phenomena can download and change into plain text; in many cases, I include passages that give readers a sense of the richness of these sources for both a historical and a contemporary understanding of near-death and related phenomena. Examples of books include Johann Engelbrecht's "The Divine Visions of John Engelbrecht" (1780), Augustine Calmet's "The Phantom World" (1850), Henri Roger Gougenot de Mousseaux's "Les hauts phénomènes de la magie" (1864), Edward H. Clarke's "Visions" (1878), William H. Harrison's "Spirits Before Our Eyes" (1879), and Frederic W. H. Myers's "Human Personality and Its Survival of Bodily Death" (1903). Examples of articles include those written by such authors as Ernesto Bozzano, Francis Power Cobbe, James H. Hyslop, Duncan MacDougall, Frank Podmore, and A. S. Wiltse.
Date: Spring 2010
Creator: Alvarado, Carlos S.
Object Type: Article
System: The UNT Digital Library
Overgeneral Memory and Posttraumatic Stress Disorder in Adults Exposed to Family Violence (open access)

Overgeneral Memory and Posttraumatic Stress Disorder in Adults Exposed to Family Violence

Childhood exposure to familial violence increases risk for adult pathology, namely posttraumatic stress disorder (PTSD) and depression. Primary PTSD symptoms of hyperarousal and avoidance are implicated in overgeneral memory (OGM) theory in prior research. Individuals with trauma history tend to report OGMs, or non-specific autobiographical memories, perhaps to avoid unpleasant arousal elicited by recalling specific events. OGM, PTSD, depression, and arousal were assessed in adults with and without familial violence history. Arousal was measured via galvanic skin response (GSR) during an autobiographical memory task (AMT), requiring memory recall in response to emotionally-valenced cue words. Familial violence history was linked to higher incidence of PTSD symptoms. Childhood psychological violence was predictive of adult PTSD. Rates of depression, OGM, and arousal did not significantly vary by violence history. Significant gender differences were found relating to type of violence exposure and adult functioning. Research limitations, clinical implications, and future research suggestions are discussed.
Date: May 2010
Creator: Amador, Amy R.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Southwest Retort, Volume 62, Number 5, January 2010 (open access)

Southwest Retort, Volume 62, Number 5, January 2010

This publication of the Dallas-Fort Worth Section of the American Chemical Society includes information about research, prominent scientist, organizational business, and various other stories of interest to the community.
Date: January 2010
Creator: American Chemical Society. Dallas/Fort Worth Section.
Object Type: Journal/Magazine/Newsletter
System: The UNT Digital Library
Southwest Retort, Volume 62, Number 6, February 2010 (open access)

Southwest Retort, Volume 62, Number 6, February 2010

This publication of the Dallas-Fort Worth Section of the American Chemical Society includes information about research, prominent scientist, organizational business, and various other stories of interest to the community.
Date: February 2010
Creator: American Chemical Society. Dallas/Fort Worth Section.
Object Type: Journal/Magazine/Newsletter
System: The UNT Digital Library
Southwest Retort, Volume 62, Number 7, March 2010 (open access)

Southwest Retort, Volume 62, Number 7, March 2010

This publication of the Dallas-Fort Worth Section of the American Chemical Society includes information about research, prominent scientist, organizational business, and various other stories of interest to the community.
Date: March 2010
Creator: American Chemical Society. Dallas/Fort Worth Section.
Object Type: Journal/Magazine/Newsletter
System: The UNT Digital Library