Meanings of “mastery” in mathematics education: creation of concourse for a research study

This article outlines the rationale for and methodological choices made in designing an online Q study. Pre-service and experienced secondary mathematics teachers in the UK use the word “mastery” to describe a specific development programme, a curriculum or a set of teacher or student behaviours; these multiple meanings inspired a Q methodological study to identify types of views held by mathematics teachers. The article details the study’s design process, from generation of research question, through concourse and Q sample creation and pilot studies, to the final research design and Q sample. In the UK, changes to teacher practice are often quickly dismissed as fads and fashions, so greater use of Q to evaluate teachers’ views on educational initiatives would be a useful tool to uncover and explain that which is valued by teachers

Isometric immersions, energy minimization and self-similar buckling in non-Euclidean elastic sheets

The edges of torn plastic sheets and growing leaves often display hierarchical buckling patterns. We show that this complex morphology (i) emerges even in zero strain configurations, and (ii) is driven by a competition between the two principal curvatures, rather than between bending and stretching. We identify the key role of branch-point (or "monkey-saddle") singularities in generating complex wrinkling patterns in isometric immersions, and show how they arise naturally from minimizing the elastic energy.Comment: 6 pages, 6 figures. This article supersedes arXiv:1504.0073

Bromotyrosine-derived natural products: synthetic and biological studies

Bromotyrosine-derived natural products are a fascinating class of compounds that are produced by marine sponges of the order Verongida. Furthermore, they exhibit a rich variety of chemical structures and display a diverse range of bioactivities which makes them of great interest to both the chemical and biological research communities. This thesis is divided into four Chapters and describes the total syntheses of five bromotyrosine-derived natural products and analogues thereof. The anticancer activity of these compounds was also investigated. In addition, studies towards the total syntheses of the ceratamines are reported. The first Chapter gives a general introduction into the history, biosynthesis, structures and biological activities of bromotyrosine-derived natural products. A background into the anticancer properties of ceratamines A and B is also provided. The research in Chapter two is concerned with bromotyrosine-derived oximes and is divided into two parts. The syntheses of the natural products (5)-bromoverongamine, ianthelline and JBIR-44 are described in Part one and the structure-activity relationship studies into these products is described in Part two. The total syntheses of subereamollines A and B are discussed in Chapter three. Furthermore, both enantiomers of the natural products were accessed and their absolute stereochemistry was unambiguously assigned. The first section of Chapter four provides an in-depth review of the research carried out by the Andersen and Coleman groups into the ceratamines. This is followed by an account of the Ley group approach towards the syntheses of these natural products

Impacts of Laurel Wilt Disease on Native Persea of the Southeastern United States

Laurel Wilt Disease (LWD) has caused severe mortality in native Persea species of the southeastern United States since it was first detected in 2003. This study was designed to document the range-wide population impacts to LWD, as well as the patterns of mortality and regeneration in Persea ecosystems. I used Forest Inventory and Analysis (FIA) data from the U.S. Forest Service to estimate Persea borbonia (red bay) populations from 2003 to 2011 to see if any decline could be observed since the introduction of LWD causal agents. Population estimates from 2003 to 2011 suggest that the population is declining. The population in Georgia significantly decreased from ca. 241.1 ± 11.9 million stems in 2003 to ca. 150.3 ± 7.9 million in 2011. Red bay densities decreased significantly in plots surveyed before and after the reported infection by an average of 89.6 live red bay stems/ha. I developed a logistic regression model to predict the probability of red bay mortality due to LWD. Number of years since LWD infection was the most significant variable, with every increase in 1 year resulting in a 153.7 % increase in odds of death. Diameter was also a significant predictor, with an increase of 1 cm DBH resulting in a 5.0 % increase in odds of death. To document the stand characteristics of red bay and swamp bay (Persea palustris) communities, I analyzed data collected from 1988-2012 by the Carolina Vegetation Survey. We used cluster analyses and species indicator analyses to group 388 plots into distinct communities. Red bay and swamp bay communities were significantly different in species composition. In addition, red bay was almost exclusively limited to maritime coastal forests, whereas swamp bay had a significantly larger geographical range, extending from near coastal setting inland through the fall-line sandhills. I surveyed plots from 1 to 10 years post LWD in South Carolina and Georgia. We did not find evidence of invasive species abundance increasing after LWD. Nearly all Persea in a plot are killed within the first two years of LWD, with the exception of smaller stems under 2.5 cm in diameter. After 10 years, Persea has regained much of the basal area prior to infection, however the structure of the stand is predominantly composed of small diameter stems (1 – 5 cm DBH). Seedling densities remain relatively the same throughout all recovery years. Contrary to initial fears, this study suggests that the native Persea species in the U.S. are not on the immediate verge of extinction from LWD at this time. However, it is still too early to say whether these species will fully recover from the disease

Forest Conversion and Degradation in Papua New Guinea 1972-2002

Quantifying forest change in the tropics is important because of the role these forests play in the conservation of biodiversity and the global carbon cycle. One of the world's largest remaining areas of tropical forest is located in Papua New Guinea. Here we show that change in its extent and condition has occurred to a greater extent than previously recorded. We assessed deforestation and forest degradation in Papua New Guinea by comparing a land-cover map from 1972 with a land-cover map created from nationwide high-resolution satellite imagery recorded since 2002. In 2002 there were 28,251,967 ha of tropical rain forest. Between 1972 and 2002, a net 15 percent of Papua New Guinea's tropical forests were cleared and 8.8 percent were degraded through logging. The drivers of forest change have been concentrated within the accessible forest estate where a net 36 percent were degraded or deforested through both forestry and nonforestry processes. Since 1972, 13 percent of upper montane forests have also been lost. We estimate that over the period 1990–2002, overall rates of change generally increased and varied between 0.8 and 1.8 percent/yr, while rates in commercially accessible forest have been far higher—having varied between 1.1 and 3.4 percent/yr. These rates are far higher than those reported by the FAO over the same period. We conclude that rapid and substantial forest change has occurred in Papua New Guinea, with the major drivers being logging in the lowland forests and subsistence agriculture throughout the country with comparatively minor contributions from forest fires, plantation establishment, and mining

Comparison of Optimism Levels and Life Stress Levels Among NCAA Division I Athletes and Non-Athletes

Researchers suggest that optimistic individuals approach life situations with the belief that outcomes will be favorable, and are more likely to exhibit better coping mechanisms when dealing with adversity and stress (Carver, & Scheier, 1987; Karadeaus, Karvelis, Argyropoulou, 2007). Moreover, the cognitive adaptation theory suggests that optimistic individuals are more likely to make appropriate cognitive adaptations to stressful situations (Lightsey, 1994; Alloy & Clements, 1992). Results concerning athletic status, gender, optimism, and stress are mixed. The purpose of this study was to compare athletes and non athletes and gender on optimism and life stress. The present study will utilize the Life Orientation Test-Revised, measuring optimism and the Undergraduate Stress Questionnaire, measuring life stress. The results will be analyzed using three independent t-tests with an alpha level set at .016 utilizing the Bonferroni adjustment technique. Discussion to take place will be between optimism and stress levels, athletic status, and gender