Contested knowledge, conflictive morality: HIV/AIDS, gender and sexuality in Puebla, Mexico

HIV/AIDS has highlighted the lack of understanding we have of cultural variations in ideas about sexual practice and identity. Whilst the South has been hit hard by the epidemic, the Mexican case is unique, and remains under-researched. Local ideas about sex, sexuality and gender, in conjunction with understandings and approaches to health affect perceptions of HIV and the risk of infection. However, health care policy evolves now in the context of an international medical community, and this thesis examines the problems these issues present. Anthropological research into transmission of HIV in Latin America has focussed almost exclusively on men, and in particular men who have sex with men. Implying that a bounded homosexual community exists, this does not account for the rapid spread of the virus in the heterosexual community. The problem of HIV/AIDS in Mexico is examined here as a shared one, and ethnographic data was gathered through informal interviewing with men and women in a self-help group, sex-workers, and low and middle income women. Public health policy normally side-steps the moral universe in the delivery of education/prevention programmes. Mexico has imported an international AIDS discourse produced in Anglo-Saxon cultures that privileges safe sex, monogamy and an idea of 'homosexual identity'. My argument that this policy cannot be applied indiscriminately iii the non-Anglo setting is borne out by the ideas people express about their sexual lives and practices. Recent theoretical work in the anthropology of gender theory has been used to explore the contradictions inherent in discussions of sexual identity, especially the differences that exist between ideological systems and practice, and some suggestions are also made for application of the research findings

Iterative Approach to Gravitational Lensing Theory

We develop an iterative approach to gravitational lensing theory based on approximate solutions of the null geodesic equations. The approach can be employed in any space-time which is ``close'' to a space-time in which the null geodesic equations can be completely integrated, such as Minkowski space-time, Robertson-Walker cosmologies, or Schwarzschild-Kerr geometries. To illustrate the method, we construct the iterative gravitational lens equations and time of arrival equation for a single Schwarzschild lens. This example motivates a discussion of the relationship between the iterative approach, the standard thin lens formulation, and an exact formulation of gravitational lensing.Comment: 27 pages, 2 figures, submitted to Phys.Rev.D, minor revisions, new reference

Quantization of Nonstandard Hamiltonian Systems

The quantization of classical theories that admit more than one Hamiltonian description is considered. This is done from a geometrical viewpoint, both at the quantization level (geometric quantization) and at the level of the dynamics of the quantum theory. A spin-1/2 system is taken as an example in which all the steps can be completed. It is shown that the geometry of the quantum theory imposes restrictions on the physically allowed nonstandard quantum theories.Comment: Revtex file, 23 pages, no figure

Effect of Past Black Spot Programs on Motorcycle Safety

The State Government of Victoria has implemented numerous accident black spot programs since the late 1970s. Commencing in the early 1990s, two substantial black spot programs, each funded by the Transport Accident Commission’s (TAC), have been completed. The first of these programs was implemented from 1992/93 to 1995/96 and had a budget of $85M. In total, there were 559 distinct sites treated under this program. A subsequent black spot program, with a budget of$240M, was implemented from 2000/2001 to 2003/2004. This program is generally referred to as the $240M Statewide Black Spot Program (SBP) and was made up of two distinct components; the Accident Black Spot component and the Potential Black Spot component. The 841 sites treated under the Accident Black Spot component were selected based on their poor history of casualty crashes over a number of preceding years. Similar methods of selecting sites for treatment were also used for earlier black spot programs. However the 285 sites treated under the Potential Black Spot component of the SBP were identified using an alternative method that did not rely on crash histories of sites. Of the$240M allocated to the Statewide Black Spot Program, approximately $20M was allocated to the Potential Black Spot component, with the remaining funds allocated to the Accident Black Spot component

Generalized Euler Angle Paramterization for SU(N)

In a previous paper (math-ph/0202002) an Euler angle parameterization for SU(4) was given. Here we present the derivation of a generalized Euler angle parameterization for SU(N). The formula for the calculation of the Haar measure for SU(N) as well as its relation to Marinov's volume formula for SU(N) will also be derived. As an example of this parameterization's usefulness, the density matrix parameterization and invariant volume element for a qubit/qutrit, three qubit and two three-state systems, also known as two qutrit systems, will also be given.Comment: 36 pages, no figures; added qubit/qutrit work, corrected minor definition problems and clarified Haar measure derivation. To be published in J. Phys. A: Math. and Ge

On spin-1 massive particles coupled to a Chern-Simons field

We study spin one particles interacting through a Chern-Simons field. In the Born approximation, we calculate the two body scattering amplitude considering three possible ways to introduce the interaction: (a) a Proca like model minimally coupled to a Chern-Simons field, (b) the model obtained from (a) by replacing the Proca's mass by a Chern-Simons term and (c) a complex Maxwell-Chern-Simons model minimally coupled to a Chern-Simons field. In the low energy regime the results show similarities with the Aharonov-Bohm scattering for spin 1/2 particles. We discuss the one loop renormalization program for the Proca's model. In spite of the bad ultraviolet behavior of the matter field propagator, we show that, up to one loop the model is power counting renormalizable thanks to the Ward identities satisfied by the interaction vertices.Comment: 14 pages, 5 figures, revte

Stokes Parameters as a Minkowskian Four-vector

It is noted that the Jones-matrix formalism for polarization optics is a six-parameter two-by-two representation of the Lorentz group. It is shown that the four independent Stokes parameters form a Minkowskian four-vector, just like the energy-momentum four-vector in special relativity. The optical filters are represented by four-by-four Lorentz-transformation matrices. This four-by-four formalism can deal with partial coherence described by the Stokes parameters. A four-by-four matrix formulation is given for decoherence effects on the Stokes parameters, and a possible experiment is proposed. It is shown also that this Lorentz-group formalism leads to optical filters with a symmetry property corresponding to that of two-dimensional Euclidean transformations.Comment: RevTeX, 22 pages, no figures, submitted to Phys. Rev.

Applying a healthcare model to Huntington's disease: the key worker approach

This paper follows on from an overview of the literature and current policy for Huntington’s disease (HD) published by the BJNN (Wilson et al. 2014). The previous paper highlighted a paucity of knowledge in terms of best practice available for those commissioning services to draw upon when planning care of those with HD. This discussion paper draws on this literature base and findings from a recent longitudinal research study from Wilson’s (2013) unpublished PhD thesis (available online at http://etheses.nottingham.ac.uk/3487/) to suggest a model of care, which may provide some guidance

Spacetime dynamics of spinning particles - exact electromagnetic analogies

We compare the rigorous equations describing the motion of spinning test particles in gravitational and electromagnetic fields, and show that if the Mathisson-Pirani spin condition holds then exact gravito-electromagnetic analogies emerge. These analogies provide a familiar formalism to treat gravitational problems, as well as a means for comparing the two interactions. Fundamental differences are manifest in the symmetries and time projections of the electromagnetic and gravitational tidal tensors. The physical consequences of the symmetries of the tidal tensors are explored comparing the following analogous setups: magnetic dipoles in the field of non-spinning/spinning charges, and gyroscopes in the Schwarzschild, Kerr, and Kerr-de Sitter spacetimes. The implications of the time projections of the tidal tensors are illustrated by the work done on the particle in various frames; in particular, a reciprocity is found to exist: in a frame comoving with the particle, the electromagnetic (but not the gravitational) field does work on it, causing a variation of its proper mass; conversely, for "static observers," a stationary gravitomagnetic (but not a magnetic) field does work on the particle, and the associated potential energy is seen to embody the Hawking-Wald spin-spin interaction energy. The issue of hidden momentum, and its counterintuitive dynamical implications, is also analyzed. Finally, a number of issues regarding the electromagnetic interaction and the physical meaning of Dixon's equations are clarified.Comment: 32+11 pages, 5 figures. Edited and further improved version, with new Section C.2 unveiling analogies for arbitrary spin conditions, and new Sec. 3.2.3 in the Supplement making connection to the post-Newtonian approximation; former Sec. III.B.4 and Appendix C moved to the (reshuffled) Supplement; references updated. The Supplement is provided in ancillary file. Matches the final published versio

Rotation and Spin in Physics

We delineate the role of rotation and spin in physics, discussing in order Newtonian classical physics, special relativity, quantum mechanics, quantum electrodynamics and general relativity. In the latter case, we discuss the generalization of the Kepler formula to post-Newtonian order $(c^{-2}$) including spin effects and two-body effects. Experiments which verify the theoretical results for general relativistic spin-orbit effects are discussed as well as efforts being made to verify the spin-spin effects