Ab initio Studies of Aluminium Halides

The catalytic fluorination of hydrocarbons facilitates the large-scale production of chlorofluorocarbons for a wide range of applications including aerosol propellants, refrigerants and solvents. Lewis acid catalysts, such as Swarts catalysts based on antimony pentafluoride, are commonly used. Recently, a sol-gel based synthesis method has been developed which yields very high surface area aluminium fluoride (HS-AlF3) that has a Lewis acidity comparable to that of the Swarts catalysts. This makes HS-AlF3 a promising candidate for use in several Lewis acid catalysed reactions. Despite the importance of the surface in the catalytic process little is known about the detailed atomic scale structure of AlF3 surfaces. Surface thermodynamics calculations, based on hybrid-exchange density functional theory, are employed to predict the composition and structure of AlF3 surfaces. The surfaces of AlF3 expose under coordinated Al ions that are potential Lewis acid sites. Under standard atmospheric conditions the AlF3 surfaces are shown to adsorb water above the under coordinated Al ions. Theoretical characterisation of the under coordinated Al ions shows that the most reactive type of site is not exposed on crystalline α-AlF3 samples, however, it is predicted to occur in small quantities on β crystallites. It is speculated that such sites occur in higher quantities on the high surface area materials. This result may explain the different reactivity of α-, β- and HS-AlF3. Our detailed understanding of AlF3 surfaces allows us to propose a reaction centre and mechanism for the dismutation of CCl2F2 on β-AlF3. Aluminium chloride is extensively used as a catalyst in Friedal-Crafts reactions. It is therefore, commonly assumed that pure crystalline AlCl3 is strongly Lewis acidic. Ab initio surface thermodynamics calculations are used to study the surfaces of crystalline AlCl3 and show that it is chemically inert

Developmental Expression of \u3cem\u3eDrop-Dead\u3c/em\u3e is Required for Early Adult Survival and Normal Body Mass in \u3cem\u3eDrosophila melanogaster\u3c/em\u3e

In Drosophila melanogaster, mutations in the gene drop-dead (drd) result in early adult lethality, with flies dying within 2 weeks of eclosion. Additional phenotypes include neurodegeneration, tracheal defects, starvation, reduced body mass, and female sterility. The cause of early lethality and the function of the drd protein remain unknown. In the current study, the temporal profiles of drd expression required for adult survival and body mass regulation were investigated. Knockdown of drd expression by UAS-RNAi transgenes and rescue of drd expression on a drd mutant background by a UAS-drd transgene were controlled with the Heat Shock Protein 70 (Hsp70)-Gal4 driver. Flies were heat-shocked at different stages of their life cycle, and the survival and body mass of the resulting adult flies were assayed. Surprisingly, the adult lethal phenotype did not depend upon drd expression in the adult. Rather, expression of drd during the second half of metamorphosis was both necessary and sufficient to prevent rapid adult mortality. In contrast, the attainment of normal adult body mass required a different temporal pattern of drd expression. In this case, manipulation of drd expression solely during larval development or metamorphosis had no effect on body mass, while knockdown or rescue of drd expression during all of pre-adult (embryonic, larval, and pupal) development did significantly alter body mass. Together, these results indicate that the adult-lethal gene drd is required only during development. Furthermore, the mutant phenotypes of body mass and lifespan are separable phenotypes arising from an absence of drd expression at different developmental stages

Neurodegeneration in \u3cem\u3eDrop-Dead\u3c/em\u3e Mutant \u3cem\u3eDrosophila melanogaster\u3c/em\u3e Is Associated with the Respiratory System but Not with Hypoxia

Mutations in the gene drop-dead (drd) cause diverse phenotypes in adult Drosophila melanogaster including early lethality, neurodegeneration, tracheal defects, gut dysfunction, reduced body mass, and female sterility. Despite the identification of the drd gene itself, the causes of early lethality and neurodegeneration in the mutant flies remain unknown. To determine the pattern of drd expression associated with the neurodegenerative phenotype, knockdown of drd with various Gal4 drivers was performed. Early adult lethality and neurodegeneration were observed upon knockdown of drd in the tracheal system with two independent insertions of the breathless-Gal4 driver and upon knockdown in the tracheal system and elsewhere with the DJ717-Gal4 driver. Surprisingly, rescue of drd expression exclusively in the tracheae in otherwise mutant flies rescued the neurodegenerative phenotype but not adult lethality. Gut dysfunction, as measured by defecation rate, was not rescued in these flies, and gut function appeared normal upon tracheal-specific knockdown of drd. Finally, the hypothesis that tracheal dysfunction in drd mutants results in hypoxia was tested. Hypoxia-sensitive reporter transgenes (LDH-Gal4 and LDH-LacZ) were placed on a drd mutant background, but enhanced expression of these reporters was not observed. In addition, manipulation of drd expression in the tracheae did not affect expression of the hypoxia-induced genes LDH, tango, and similar. Overall, these results indicate that there are at least two causes of adult lethality in drd mutants, that gut dysfunction and neurodegeneration are independent phenotypes, and that neurodegeneration is associated with tracheal expression of drd but not with hypoxia

Training Methods Utlilized by Independent Restaurant Managers

Formal, systematic training has always been cited as a major need for the future success of hospitality operations. However, one other aspect of the job might be the development of a train-the-trainer curriculum for hospitality management students. The author studies the relationship between training preparation and training methods utilized by restaurant managers and explores this need

Review of Hospitality Ethics Research in 2008

This paper reviews and analyzes 83 articles on the topic of hospitality ethics that appeared in the hospitality journals in the Hospitality and Tourism Index in the year of 2008. Figures in this paper show self emerging topic categories, journals, and dates of publication so that readers can see how the 2008 articles fit with the other 433 articles analyzed and reviewed since 1990. Findings indicate the most obvious change in 2008 to be from concern over the unethical behaviors of individuals in U.S. hospitality and hospitality related operations, to the more global concerns of sustainability for both companies and communities

What Is Teacher Effectiveness? A Case Study Of Educator Perceptions In A Midwest Elementary School

ABSTRACT Research has shown that teacher effectiveness is the most significant school-level factor impacting student achievement (McCaffrey, Koretz, Lockwood, & Hamilton, 2004; Rivkin, Hanushek, & Kain, 2005; Rockoff, 2004), and yet little is known about teacher and administrator perceptions of teacher effectiveness. Through this qualitative case study, I explored the perceptions of elementary school teachers and their principal regarding teacher effectiveness. I examined the extent to which there was a shared understanding of teacher effectiveness, if teachers and their principal perceptions were the same or different, and how teacher perceptions aligned to the teacher evaluation system used at this school. Semi-structured interviews, observations of classrooms and team meetings, and an analysis of authentic school documents were used in this in-depth study of one single. Shared and divergent perceptions between classroom teachers, their principal, and the teacher evaluation system were revealed. The perceptions of teacher effectiveness are critical in supporting teacher growth. Our ever-changing classrooms and the students within them require that we continually update what effective and successful teaching looks like. This research will impact education by enabling teachers and administrators to reflect on their own understanding and vision of teacher effectiveness and plan for successful school improvement. This study is vital for educators striving to become more effective in increasing student achievement and for the school systems supporting this effort. Keywords: teacher effectiveness, teacher evaluation, teacher improvement, school improvemen

Literature circles and improved comprehension in struggling readers

The purpose of this project was to examine Literature Circles for their effectiveness with struggling readers in upper elementary classrooms and reading rooms. Research questions include, what is the impact of Literature Circles on struggling readers in upper elementary grades? and, what scaffolds help struggling readers be successful in Literature Circles? The literature review defines Literature Circles in their various forms, and details how to begin using this method in the classroom with groupings including struggling readers. Procedures and scaffolds are identified that have had proven results with struggling readers through various research methods. Ideas for teacher assessment, self-assessment and peer assessment are included. A Literature Circle Four Day Workshop for Title I teachers presents this information in PowerPoint format. Research indicates that Literature Circles can be effective for struggling readers when teachers encourage discussion and debate, and when scaffolds and an atmosphere of trust are present in the classroom

The Development and Design of an Exit Program for High School Career Pathway Graduates

This project is about a new concept; a program that will change the way we assess high school students. The purpose of this project was to design and implement an assessment portfolio process entitled The Tiger Futures Program for Ephrata High School in the state of Washington. The program was designed as a three-year pilot program beginning in the 2000-2001 school year and fully implemented by 2002-2003. At that time it will become a graduation requirement. The program involved career pathways, portfolios, and exit interviews. The results showed that the program followed state and district standards and requirements. It also provided opportunities for students to have hands on experiences related to future career and employment choices, take ownership and pride in their work, and work on speaking, writing, presenting, organizing, and evaluating skills. Recommendations for the 2001-2002 school year are discussed