Wilson line approach to gravity in the high energy limit

We examine the high energy (Regge) limit of gravitational scattering using a Wilson line approach previously used in the context of non-Abelian gauge theories. Our aim is to clarify the nature of the Reggeization of the graviton and the interplay between this Reggeization and the so-called eikonal phase which determines the spectrum of gravitational bound states. Furthermore, we discuss finite corrections to this picture. Our results are of relevance to various supergravity theories, and also help to clarify the relationship between gauge and gravity theories.Comment: 33 pages, 5 figure

Finding home: A collection of travel essays from a semester in Florence

In January of 2014, I embarked on a study abroad trip to the incredible city of Florence, Italy. The adventures, food, and cultures I encountered along the next three months would forever change the way I saw the world. What I expected to be an exciting adventure turned out to be a season of true discovery. Through this discovery, I came to redefine how I interacted with it, and what it meant to truly be home

Investigation of timetabling in tertiary institutions in Southern Africa

This paper deals with approaches to the timetabling problem, focusing on tertiary institutions in Southern Africa. A questionnaire which dealt with, inter alia, student population, number of class groups, methods used for timetabling and local constraints, was distributed to tertiary institutions in Southern Africa. The response rate was over 80%. Analysis of the responses yielded a number of interesting results, chief among these being that there is little consensus on any one method, and that the timetabling process is not fully automated in any institution. The analysis further indicated that a great deal of time and effort is involved in the process, up to 200 person-hours in some institutions. This paper details previous work in the field and outlines results from the questionnaire. Future research will be directed towards either finding a more efficient approach to the problem, or detemining which of the current methods is in fact most effective

The cosmological tree theorem

A number of diagrammatic “cutting rules” have recently been developed for the wavefunction of the Universe which determines cosmological correlation functions. These leverage perturbative unitarity to relate particular “discontinuities” in Feynman-Witten diagrams (with cosmological boundary conditions) to simpler diagrams, in much the same way that the Cutkosky rules relate different scattering amplitudes. In this work, we make use of a further causality condition to derive new cutting rules for Feynman-Witten diagrams on any time-dependent spacetime background. These lead to the cosmological analogue of Feynman’s tree theorem for amplitudes, which can be used to systematically expand any loop diagram in terms of (momentum integrals of) tree-level diagrams. As an application of these new rules, we show that certain singularities in the wavefunction cannot appear in equal-time correlators due to a cancellation between “real” and “virtual” contributions that closely parallels the KLN theorem. Finally, when combined with the Bunch-Davies condition that certain unphysical singularities are absent, these cutting rules completely determine any tree-level exchange diagram in terms of simpler contact diagrams. Altogether, these results remove the need to ever perform nested time integrals when computing cosmological correlators

Scald in granny smith apples

The Granny Smith has been the most widely grown variety of apple in Western Australia for many years. In 1946 a survey showed that more than one-third of the apple trees growing in this State were Granny Smiths and new plantings and reworkings since then have been predominately of this variety. Production in 1947, a very heavy crop year, exceeded a million bushels, which represented about 40 per cent, of the total apple crop for that year. This decided preference shown by growers for the Granny Smith emanates from its suitability to West Australian conditions and the strong demand for this popular apple both on the overseas and local market. However, in common with this variety grown under similar climatic conditions elsewhere, it is very subject to scald when cool stored for long periods

A guide to the harvesting of plums for export

Western Australia is well situated geographically to supply the demand for plums on the Singapore market and over the past 10 years, a substantial export trade has been developed. Growers have found this outlet profitable, and increased plantings of suitable varieties have been made. During the 1957 season—a record export year—almost 40,000 boxes were shipped

The handling, presentation and storage of stone fruits

The stone fruit industry in Western Australia produces up to 250,000 bushels of fruit per annum. The crop is disposed of mainly as fresh fruit on the local market, but during the last few years a useful outlet for certain varieties of plums has developed in Singapore which imports about 12,000 bushels each year. Stone fruits are not dried commercially and processing is confined mainly to the use of surplus fruit for jam making

DNC oil sprays for deciduous fruits

The climate of any particular place plays a very important part in determining the kinds of varieties of fruits which can be successfully grow, and one of the most common manifestations of unfavourable weather conditions in deciduous fruits is a condition usually termed delayed foliation . It is characterised by delayed and irregular blossoming and foliation, failure of many fruit and leaf buds to open and shredding of blossom buds