Orbit counting in conjugacy classes for free groups acting on trees

In this paper we study the action of the fundamental group of a finite metric graph on its universal covering tree. We assume the graph is finite, connected and the degree of each vertex is at least three. Further, we assume an irrationality condition on the edge lengths. We obtain an asymptotic for the number of elements in a fixed conjugacy class for which the associated displacement of a given base vertex in the universal covering tree is at most $T$. Under a mild extra assumption we also obtain a polynomial error term.Comment: 13 pages, additional section discusses error terms, revised expositio

Addendum: an analogue of Artin reciprocity for closed orbits of skew products

One of the unfulfilled aims of the authors of the preceding paper [W. Parry and M. Pollicott. An analogue of Bauer’s theorem for closed orbits of skew products. Ergod. Th. & Dynam. Sys. 28 (2008), 535–546] was to find a dynamical analogue of Artin reciprocity. In this addendum, we present one such version, suggested by work of Sunada

Applications of high thermal conductivity composites to electronics and spacecraft thermal design

Recently, high thermal conductivity continuous graphite fiber reinforced metal matrix composites (MMC's) have become available that can save much weight over present methods of heat conduction. These materials have two or three times higher thermal conductivity in the fiber direction than the pure metals when compared on a thermal conductivity to weight basis. Use of these materials for heat conduction purposes can result in weight savings of from 50 to 70 percent over structural aluminum. Another significant advantage is that these materials can be used without the plumbing and testing complexities that accompany the use of liquid heat pipes. A spinoff of this research was the development of other MMC's as electronic device heat sinks. These use particulates rather than fibers and are formulated to match the coefficient of thermal expansion of electronic substrates in order to alleviate thermally induced stresses. The development of both types of these materials as viable weight saving substitutes for traditional methods of thermal control for electronics packaging and also for spacecraft thermal control applications are the subject of this report

Equidistribution of holonomy in homology classes for Anosov flows

We obtain equidistribution results for the holonomies of periodic orbits of Anosov flows lying in a prescribed homology class. We apply this to frame flows

Electrophysiological correlates of event segmentation: how does the human mind process ongoing activity?

The human mind decodes, processes, and makes sense of a continual flow of dynamic information, taken from an array of sensory inputs. Compelling behavioural and neuroimaging evidence reveals that humans segment activities into meaningful chunks for processing, and this phenomenon has profound implications for learning, memory and understanding the world around us (Newtson, 1973; Zacks and Tversky, 2001; Zacks et al., 2001). Whilst the existence of event segmentation is widely accepted, it remains unclear what cognitive mechanisms drive this ability.This thesis constitutes a series of behavioural and neuroimaging experiments that investigate top-down and bottom-up influences on event segmentation. The neuroimaging studies presented here are novel; they extend the field by investigating event segmentation using scalp-recorded electroencephalography (EEG). Event Related Potentials (ERPs, derived from EEG using signal-averaging procedures) showed that the perceptual processing of event boundaries is differentially sensitive to the segmentation of activities into small or large chunks, consistent with findings from previous neuroimaging research (Zacks et al., 2001). In contrast with previous findings, the electrophysiological investigations elicited responses that were clearly affected by manipulating top-down information (e.g., participant's knowledge about the activity being segmented). The results from the studies reported in the thesis support an account of the perceptual processing of event boundaries, which incorporates both top-down and bottom-up influences

Malta and the Nineteenth Century Grain Trade:British free trade in a microcosm of Empire?

It is often assumed that Britain’s colonies followed the British doctrine of free trade in the second half of the nineteenth century. Malta, which became a British colony in 1814, did indeed become an early free trader. However, she failed to liberalize the grain trade, even when the mother country famously repealed the Corn Laws. This paper documents that although institutions changed over the years, the ad valorem equivalents of the duties on wheat did not. The reason for this seems to be that administrators were convinced that is was not possible to fund government spending in any other way. The duties on grain in Malta were therefore not protectionist, but rather for revenue purposes, in contrast to the UK Corn Laws. Taxing an inelastic demand for foreign wheat by Maltese, who were unable to grow enough food to support themselves, was certainly an effective way of raising revenue, but probably not the fairest one, as contemporaries were well aware.peer-reviewe

A review of research in spelling at Boston University: 1954-1959

Thesis (Ed.M.)--Boston UniversityPurpose: To compare the flash-card method of instruction with the study-test method of teaching spelling in grade four and to determine which of these methods will prove more effective [TRUNCATED