Excavations in the South Transept of St. Mary's Abbey, York

Landscaping developments on the site of St Mary’s Abbey, situated within the Museum Gardens, encountered in situ archaeological remains in the south transept. A substantial area of a wall foundation was uncovered and a chapel apse discovered. The published record of the architectural features within this area is piecemeal and does not account for the unusual position of this feature within the transept

The Effect of Changes in pH on the Production and Respiration Rates of Native Tape Grass, Vallisneria Americana

In the past century, the world has seen an increase in the amount of carbon dioxide (CO2) in the atmosphere. The rise in CO2 can put stress on aquatic ecosystems due to ocean acidification, an overall decrease in the pH of the ocean’s waters. Freshwater ecosystems, already stressed by pollution and recent increases in the number of invasive species are also showing signs of acidification due to the increase in CO2. The effect of the rise in acidity is known to be harmful to calcifying organisms, but the effect on freshwater submerged aquatic vegetation (SAV) is not well studied. The invasive SAV Hydrilla verticallata (Hydrilla) and native SAV Vallisneria americana (tape grass) often compete for similar environments in the freshwater portions of the Chesapeake Bay. Previous studies on the effects of pH changes on Hydrilla found that the SAV may be experiencing phenotypic plasticity allowing it to continue to produce and respire even at the most acidic treatments. This study looked at the respiration and production rates of Vallisneria americana under differing pH’s. Samples of tape grass were incubated in water with a pH ranging from 8.2 units to 5.7 units in a light gradient box for the production treatments and a dark box for the respiration treatments. It was found that at the pH’s closest to the control 7.2, the 6.7 and 8.2 treatments, tape grass experienced no production. In the 5.7 and 6.2 treatments, tape grass experienced significantly higher production rates. Data was collected and analyzed using a One-Way ANOVA and a Tukey’s HSD test. There was a significant difference found in both the production and respiration rates at the varying pH levels. With the stress of an increase in acidity and invasive species, the results of this study suggest that tape grass will continue to produce and respire as a crucial part of freshwater ecosystems

Hedgehog Bases for A_n Cluster Polylogarithms and An Application to Six-Point Amplitudes

Multi-loop scattering amplitudes in N=4 Yang-Mills theory possess cluster algebra structure. In order to develop a computational framework which exploits this connection, we show how to construct bases of Goncharov polylogarithm functions, at any weight, whose symbol alphabet consists of cluster coordinates on the $A_n$ cluster algebra. Using such a basis we present a new expression for the 2-loop 6-particle NMHV amplitude which makes some of its cluster structure manifest.Comment: 32 pages; v2: minor corrections and clarification

WORKING ALLIANCES: THE IMPLICATIONS OF PERSON-CENTERED THEORY FOR STUDENT-TEACHER RELATIONSHIPS AND LEARNING

In this dissertation project, I interview four therapists and four writing teachers to learn if there were any significant similarities in differences in their approaches to dyadic relationships with students and clients. By dyadic, I mean what happens between individuals in a 1-on-1 setting when subjectivities collide. I was guided in my investigation by the core concepts of person-centered theory, which have heavily influenced the work of clinical therapists for the past half-century or more. These concepts are congruence, or whether one’s behaviors and speech match what one is feeling; empathy, the process of entering and becoming familiar with another’s private, perceptual world; and positive regard, or demonstrating that one accepts and values others, including their feelings, opinions, and selves. I found that teachers and therapists both faced challenges in developing, managing, and repairing relationships, and espoused similar values about relating to others. However, therapists were able to draw on clinical theories and tools for relating for which no parallels exist in writing pedagogy. For example, in the many teaching manuals I surveyed, I found hardly any page space devoted to the challenge of teacher-student relationships. Results from my study include conceptualizations of how person-centered intellectual tools might be synthesized with current writing pedagogy both in theory and in training. Furthermore, I hope to draw more attention to the nuances of dyadic relationships, and the unfortunate scarcity of tools that writing pedagogy currently has for working in them

Polymerisations of hydroxyacids performed by Candida rugosa lipase

This thesis is describes the polymerisation of hydroxyacids catalysed by the Candida rugosa lipase (CRL). Chapter 1 involves a background introduction to enzymes in general and specifically lipases. Several commercial applications of lipases are discussed, followed by the use of lipases in the synthesis of polymeric materials. Chapter 2 covers the experimental work carried out on our system to determine the optimal conditions for the enzymatic reaction to take place. For CRL these are using hexane at 55 C. Several ω-hydroxyacids are investigated for the relative rates of reaction, using (^1)H NMR and GPC analytical techniques. The use of molecular sieves is evaluated, as is reprecipitation from hexane, to establish the optimal method for obtaining high molecular weight polymers. Chapter 3 includes a comparison of the six co-hydroxyacids which were used, and expresses the observation that CRL has a preference for the hydroxyacids with 8 and 9 carbons. There is an investigation into the sequence of the assembly of the polymer using deuterium labelled monomers, and several functionalised monomers are also polymerised. A comparison is made between the enzymatic and a chemically (Ti(0Bu)(_4)) catalysed process. Chapter 4 introduces molecular modelling studies, and docks 9-hydroxy- nonanoic acid into the cavity beyond the enzyme active site. Various potential affinity labels are designed to covalently modify the active site cavity, and are thus synthesised to determine if the polymerisation process can be inhibited. Finally in this Chapter an investigation into the stereospecificity of CRL is undertaken, using 10-hydroxy- undecanoic acid, and a binding mechanism between the enzyme and the substrate is proposed. Chapter 5 outlines the synthetic pathways to all of the materials which are synthesised in this thesis, and Chapter 6 describes the experimental routes to each of these materials