Top Spin and Experimental Tests

We examine pair mass dependence near threshold as a means to measure the spin of the top quark in hadron collisions, and we discuss the possibility that a top squark signal could be hidden among the top events.Comment: 9 pages, RevTeX, 3 figures. Contribution to the Thinkshop on Top-Quark Physics for the Tevatron Run II, Fermilab, October 16 - 18, 199

Multi-Scale Mathematical Modelling of Brain Networks in Alzheimer's Disease

Perturbations to brain network dynamics on a range of spatial and temporal scales are believed to underpin neurological disorders such as Alzheimer’s disease (AD). This thesis combines quantitative data analysis with tools such as dynamical systems and graph theory to understand how the network dynamics of the brain are altered in AD and experimental models of related pathologies. Firstly, we use a biophysical neuron model to elucidate ionic mechanisms underpinning alterations to the dynamics of principal neurons in the brain’s spatial navigation systems in an animal model of tauopathy. To uncover how synaptic deficits result in alterations to brain dynamics, we subsequently study an animal model featuring local and long-range synaptic degeneration. Synchronous activity (functional connectivity; FC) between neurons within a region of the cortex is analysed using two-photon calcium imaging data. Long-range FC between regions of the brain is analysed using EEG data. Furthermore, a computational model is used to study relationships between networks on these different spatial scales. The latter half of this thesis studies EEG to characterize alterations to macro-scale brain dynamics in clinical AD. Spectral and FC measures are correlated with cognitive test scores to study the hypothesis that impaired integration of the brain’s processing systems underpin cognitive impairment in AD. Whole brain computational modelling is used to gain insight into the role of spectral slowing on FC, and elucidate potential synaptic mechanisms of FC differences in AD. On a finer temporal scale, microstate analyses are used to identify changes to the rapid transitioning behaviour of the brain’s resting state in AD. Finally, the electrophysiological signatures of AD identified throughout the thesis are combined into a predictive model which can accurately separate people with AD and healthy controls based on their EEG, results which are validated on an independent patient cohort. Furthermore, we demonstrate in a small preliminary cohort that this model is a promising tool for predicting future conversion to AD in patients with mild cognitive impairment

SUSY Production Cross Sections

We summarize the status of next-to-leading order perturbative quantum chromodynamics (pQCD) calculations of the cross sections for the production of squarks, gluinos, neutralinos, charginos, and sleptons as a function of the produced sparticle masses in proton-antiproton collisions at the hadronic center-of-mass energy 2 TeV.Comment: 7 pages, latex, plus one .eps figure; subgroup summary for the SUGRA working group of the Fermilab workshop Physics at Run II -- Supersymmetry/Higg

Predictions for associated production of gauginos and gluinos at NLO in SUSY-QCD

NLO SUSY-QCD contributions to associated production of gluinos and gauginos are shown to enhance the cross sections by about 10% at the Tevatron and by as much as a factor of two at the LHC. They shift the mass determinations or discovery limits, soften the $p_T$ spectra, and stabilize the predictions against variations of the renormalization and factorization scales.Comment: 4 pages, Latex (uses Moriond style file), 8 eps-figures. Talk presented at the XXXVth Rencontres de Moriond, QCD and High Energy Hadronic Interactions, Les Arcs, France, March 18-25, 200

Next-to-leading Order SUSY-QCD Calculation of Associated Production of Gauginos and Gluinos

Results are presented of a next-to-leading order calculation in perturbative QCD of the production of charginos and neutralinos in association with gluinos at hadron colliders. Predictions for cross sections are shown at the energies of the Fermilab Tevatron and CERN Large Hadron Collider for a typical supergravity (SUGRA) model of the sparticle mass spectrum and for a light gluino model.Comment: 3 pages, latex, 4 figures, paper presented by E. L. Berger at ICHEP 2000, the XXXth International Conference on High Energy Physics July 27 - August 2, 2000, Osaka, Japa

Next-to-Leading Order SUSY-QCD Predictions for Associated Production of Gauginos and Gluinos

We present complete results of a next-to-leading order calculation of the production of gaugino-like charginos (\chargino) and neutralinos (\neutralino) in association with gluinos (\gluino) at hadron colliders, including the strong corrections from the exchange of colored particles and sparticles. Adopting a variety of models for the sparticle mass spectrum, including typical supergravity (SUGRA) models and a light gluino model, we provide predictions for total and differential cross sections at the energies of the Fermilab Tevatron and CERN Large Hadron Collider (LHC).Comment: 91 pages, Latex, including 26 figure

Fetal Alcohol Syndrome Among Aboriginal People in Canada: Review and Analysis of the Intergenerational Links to Residential Schools

This report examines FAS in the context of the intergenerational effects of the residential school era