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A Computational Study on 18+δ Organometallics

A Computational Study on 18+δ Organometallics

Date: May 2002
Creator: Yu, Liwen
Description: The B3LYP density functional has been used to calculate properties of organometallic complexes of Co(CO)3 and ReBr(CO)3, with the chelating ligand 2,3-bisphosphinomaleic anhydride, in 19- and 18-electron forms. The SBKJC-21G effective core potential and associated basis set was used for metals (Co/Re) and the 6-31G* basis set was used for all other elements. The differences of bond angles, bond distances, natural atomic charges and IR vibrational frequencies were compared with the available experimental parameters. The differences between the 19- and 18-electron systems have been analyzed. The results reveal that the 19th electron is mostly distributed over the ligand of 2,3-bisphosphinomaleic anhydride, although partially localized onto the metal fragment in 1 and 2*. Two different methods, IR-frequencies and natural atomic charges, were used to determine the value of δ. Present computed values of δ are compared with available experimental values, and predictions are made for unknown complexes.
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Computer supported collaboration: Is the transfer of cognitive structures mediated by mode of communication?

Computer supported collaboration: Is the transfer of cognitive structures mediated by mode of communication?

Date: May 2002
Creator: Bandy, Kenneth E.
Description: The objective of this study was to observe evidence of structural transfer among subjects in a group problem-solving activity and determine whether mode of collaborative technology or use of a priming agent affected the nature of transferred structures. Evidence for structural transfer is found in three theoretical perspectives: organizational ditransitive (linguistic) verb structures, adaptive structuration theory, and mental model transfer theory. Dependent variables included various grammatical structures and coefficients derived from pretest and posttest scores on David Kolb's Learning Styles Inventory, modified for the experiment. The combination of changes in grammatical frequencies and learning style may suggest that one or more media or the priming agent may affect structural transfer. Results indicate that groups using the GroupSystems™ collaborative technology produced less overall linguistic content than did subjects using a generic chat system, but employed more complex language as indicated by frequency of the organizational ditransitive verb structure. Also, subjects supplied with an organization chart (priming agent) during the group problem-solving session experienced greater change on the learning styles inventory than did those participating in the session without the chart. These findings suggest that mode of communication and use of priming agents may contribute positively or negatively to the transfer of ...
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The Construct Validity of Self-Reported Historical Physical Activity

The Construct Validity of Self-Reported Historical Physical Activity

Access: Use of this item is restricted to the UNT Community.
Date: May 2002
Creator: Bowles, Heather R.
Description: The purpose of this study was to determine the construct validity of self-reported historical walking, running, and jogging (WRJ) activity. The criterion measure was concurrent performance on a maximal treadmill test. Subjects completed a medical exam and treadmill test between the years 1976 and 1985, and completed a follow-up questionnaire in 1986. Questionnaire included an item that assessed WRJ for each year from 1976 through 1985. Data analysis included Spearman correlations, partial correlations, ANOVA, and ANCOVA. Results indicated self-reported historical WRJ can be assessed with reasonable validity when compared with concurrently measured treadmill performance, and there is no decay in the accuracy of this reporting for up to ten years in the past.
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A content analysis of reading software commercially available for Pre-K to 3rd grade children.

A content analysis of reading software commercially available for Pre-K to 3rd grade children.

Date: May 2002
Creator: Nakjan, Sutat
Description: The purpose of this qualitative study was to investigate the content and characteristics of the currently available commercial reading software for Pre-K through third grade children. The design of the study was a content analysis. Based on the evaluation rubric established by the researcher, ten commercial reading software were selected to be analyzed. By reviewing and transcribing, the data were obtained, and then coded, categorized, and interpreted. The findings from the analysis revealed that all reading software programs offered exercised for practicing basic phonics skills; the alphabetic principle, letter-sound association, word knowledge, sentence building, and reading comprehension. Depending on the software developers, phonics-based practice was presented in two ways; separate skill-based practice emphasis and storybook-reading emphasis. All software programs utilized drill-and-practice, direct instruction and mastery learning methods and utilized gaming strategies to motivate and engage the learners. Multimedia technology was used to make the software more appealing. All reading software programs were developed on the perspectives that view learning to read as the continuum of a child's oral language development and background experience about words. It is recommended that parents and teachers review and select the software based on reliable information sources, use the software as supplementary practice based on ...
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A correlative study of gender and social style.

A correlative study of gender and social style.

Date: May 2002
Creator: Gross, Amanda
Description: This study examines the concepts of social style and gender to determine if a relationship exists between the two constructs. The hypotheses suggested a direct relationship between the categories of the BSRI (masculine, feminine, androgynous, and undifferentiated) and the Social Style Analysis (driver, amiable, expressive, and analytical). Ninety-four participants completed two self-report surveys. Chi-square analysis performed on the data found a significant relationship between feminine and amiable as well as androgynous and expressive. While the analysis suggested that masculine/driver and undifferentiated/analytical were not independent, the relationship found was not significant.
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The Crater of Diamonds: A History of the Pike County, Arkansas, Diamond Field, 1906-1972

The Crater of Diamonds: A History of the Pike County, Arkansas, Diamond Field, 1906-1972

Access: Use of this item is restricted to the UNT Community.
Date: May 2002
Creator: Henderson, John C.
Description: The first diamond mine in North America was discovered in 1906 when John W. Huddleston found two diamonds on his farm just south of Murfreesboro in Pike County, Arkansas. Experts soon confirmed that the diamond-bearing formation on which Huddleston made his discovery was the second largest of its kind and represented 25 percent of all known diamond-bearing areas in the world. Discovery of the field generated nearly a half century of speculative activity by men trying to demonstrate and exploit its commercial viability. The field, however, lacked the necessary richness for successful commercial ventures, and mining was eventually replaced in the early 1950s by tourist attractions that operated successfully until 1972. At that time the State of Arkansas purchased the field and converted it to a state park. Thus this work tell the rich and complicated story of America'a once and only diamond field, analyzes the reasons for the repeated failures of efforts to make it commercially viable, and explains how it eventually succeeded as a tourist venture.
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Detecting the presence of disease by unifying two methods of remote sensing.

Detecting the presence of disease by unifying two methods of remote sensing.

Date: May 2002
Creator: Reames, Steve
Description: There is currently no effective tool available to quickly and economically measure a change in landmass in the setting of biomedical professionals and environmental specialists. The purpose of this study is to structure and demonstrate a statistical change-detection method using remotely sensed data that can detect the presence of an infectious land borne disease. Data sources included the Texas Department of Health database, which provided the types of infectious land borne diseases and indicated the geographical area to study. Methods of data collection included the gathering of images produced by digital orthophoto quadrangle and aerial videography and Landsat. Also, a method was developed to identify statistically the severity of changes of the landmass over a three-year period. Data analysis included using a unique statistical detection procedure to measure the severity of change in landmass when a disease was not present and when the disease was present. The statistical detection method was applied to two different remotely sensed platform types and again to two like remotely sensed platform types. The results indicated that when the statistical change detection method was used for two different types of remote sensing mediums (i.e.-digital orthophoto quadrangle and aerial videography), the results were negative due to ...
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Determination of the shelf life of aluminum electrolytic capacitors.

Determination of the shelf life of aluminum electrolytic capacitors.

Date: May 2002
Creator: Wynne, Edward McFaddin
Description: The aluminum electrolytic capacitor is used extensively in the electric utility industry. A factor limiting the storage of spare capacitors is the integrity of the aluminum oxide dielectric, which over time breaks down contributing to a shelf life currently estimated at one nuclear power electric generating station to be approximately five years. This project examined the electrical characteristics of naturally aged capacitors of several different styles to determine if design parameters were still within limits. Additionally, the effectiveness of a technique known as “Reforming” was examined to determine its impact on those characteristics.
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Dimensions in random constructions.

Dimensions in random constructions.

Date: May 2002
Creator: Berlinkov, Artemi
Description: We consider random fractals generated by random recursive constructions, prove zero-one laws concerning their dimensions and find their packing and Minkowski dimensions. Also we investigate the packing measure in corresponding dimension. For a class of random distribution functions we prove that their packing and Hausdorff dimensions coincide.
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Distant Proximity: Mapping Presence and Absence

Distant Proximity: Mapping Presence and Absence

Date: May 2002
Creator: Mitroi, Tudor
Description: Chapter I presents my background as an artist born and raised in Romania, and describes my artwork in connection with my interests and experiences. Maps and traditional Romanian art are important sources of influence. The questions in the statement of problem deal with the way ideas, references to various elements, and installation impact the artwork. Chapter II discusses the installation at the Dallas Visual Art Center, the creative process, and how the artwork addressed the questions in the statement of problem. Important points are: a step into three-dimensionality with the tall, freestanding pieces painted on both sides, the use of topographical contours in creating shapes, issues of form and content as expressed in the painted surfaces, and the interaction of the individual works in the installation.
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