An Australian abroad : the secret life of the brushtail possum (Trichosurus vulpecula) : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Veterinary Science at Massey University, Manawatu, New Zealand

The “superspreader” hypothesis relates disease transmission to social contacts and assumes transmission is driven by the frequency, type and distribution of contacts among infected and susceptible individuals. I investigated characteristics of brushtail possum (Trichosurus vulpecula) home ranges for six wild free-living subpopulations, (four grids were studied; all of them before possum depopulation and two of them after possum depopulation) constructing social networks relevant to bovine tuberculosis (TB) transmission before and after depopulation. I also experimentally infected possums with a novel strain of TB to monitor secondary case infections in relation to these contact and other factors, including population density and sex ratio. Before depopulation home range estimates showed adult males had larger home ranges than female and younger possums. Home range overlap and area of overlap differed between subpopulations, and possum sex and age; with adult males having more and larger overlaps with other possums. Possums were fitted with proximity-logging collars and contacts registered between April and October, 2012. The number of connections an individual has with others and the probability of the distribution of contacts it has within the population, or node degree and betweenness, also known as the shortest distance between individuals, were associated with sex, with males having higher values for each. Males also contacted more possums than females. Post-depopulation results showed an influx of male possums, higher population density, and smaller home range sizes than before depopulation. Possums post-depopulation also lacked an apparent ‘routine’ in contact networks, interacting with other possums haphazardly. The greater level of contact among adult males, than before depopulation, and their effects on recovering populations post-depopulation, was likely the cause of more TB infection in adults and males. This thesis provides empirical evidence that adult male possums have home range and contact network characteristics that are likely to enhance their involvement in the transmission and persistence of TB, relative to female and younger possums. Observations of experimentally infected individuals showed that infected males survived longer than females and that, as a consequence, those males potentially acted as a “supershedding” subgroup. I therefore provide evidence that adult male possums are the most important drivers of TB transmission and persistence of infection in populations, and could be targeted for control measures

Numerical solution of the three-dimensional Navier-Stokes equations

Imperial Users onl

The effect of polypropylene fibres within concrete with regard to fire performance in structures

Purpose – The purpose of this paper is to examine the effect of various polypropylene fibre additions (types and volume) to concrete with regard to explosive spalling when subject to high temperatures similar to those experienced in building or tunnel fires. Design/methodology/approach – Medium strength concrete was manufactured with varying proportions of polypropylene fibres. Plain control samples were used to determine the original concrete strength and this was used as a benchmark following high temperature heat tests to evaluate the surface condition and final compressive strength. A pilot study was used to determine an appropriate heat source for the test. This was three Bunsen burners, however sufficient heat could not be generated within 150mm concrete cubes and the concrete was shown to be a significant insulator and fire protection for structural members. The concrete test cubes were tested in a saturated condition which may reflect conditions where concrete is used in an external environment and thus is subject to soaking. Findings – One hundred and fifty millimetre concrete cubes with and without fibres were placed into a furnace at 1,000°C. Explosive spalling was shown to be reduced with the use of polypropylene fibres but the final compressive strength of concrete was significantly reduced and had little residual structural value after a two hour period of heating. Research limitations/implications – As the concrete tested was saturated, this condition provided a worst case scenario with regards to the build up of hydrostatic and vapour pressure within the cube. A range of percentage moisture contents would produce a more evenly balanced view of the effects of fibres in concrete. A single grade of concrete was used for the test. As the permeability of concrete influences the rate at which steam can escape from the interior of a saturated concrete cube, testing a range of concrete strengths would show this aspect of material performance with regard to spalling and final residual strength. Further research is recommended with regard to moisture contents, strengths of concrete and a range of temperatures

The Perceptions of Black Teachers Regarding Their Decision to Teach and Satisfaction with Their Work Experiences in Predominantly White K-12 Schools

The purpose of this study was to examine the perceptions of Black teachers regarding their decision to teach and the satisfaction with their work experiences in predominantly White K-12 schools. A total of 118 teachers who were identified as Black and as employees of a predominantly White school were invited to complete a survey via email. A total of 56 did in fact respond. Of that 56, only 51 respondents provided enough usable data (which is defined as a survey completed in full). The data, which came from a Perceptions Survey, meant to report levels of job satisfaction as it relates to perceptions of work experiences. The primary research question was: What are the perceptions of Black teachers regarding their satisfaction with their work experiences in predominantly White K-12 schools? The subsequent sub-question was: How do those work experiences impact Black teachers’ decision to continue teaching, be promoted from teaching, or recommend a career in teaching to other Black people? The independent or predictor variables were: spirituality, cultural acceptance, interracial relationships, intra-racial relationships, mentoring, and advancement opportunities. The dependent variable was: job satisfaction. A bivariate correlation analysis was used to determine if the predictor variables should be grouped as components using their variance scores. The variance scores did indeed indicate the need to group the predictor variables as components. Those components were named as relationships, oppression, and mindset. The component named oppression had a significant correlation with job satisfaction. Overall the findings indicated that a large percent of Black teachers in predominantly White schools are not satisfied with their job. Further research about the job satisfaction of Black teachers is recommended because of the growing need to recruit and keep Black teachers in our schools

Constitutional Theory & The Political Process

Constitutional Theory is at the center of legal and political debates in the United States. In recent decades, legal scholars and politicians alike increasingly treat their respective theories of interpretation as articles as faith. From originalism, to textualism, to treating the constitution as a “living document,” many contend that their theory is better than the others and offers the most suitable answers to raging constitutional debates. This paper tests that popular convention by examining how the Constitution was written, and whether there is indeed any one way to interpret it. I will then compare and contrast two dominant theories of interpretation; Originalism and Legal Pragmatism to show their strengths and weaknesses. Further, I will examine four landmark Supreme Court cases to outline examples of where both theories got it right and wrong. This analysis will reveal that both theories lead to destructive results when presiding judges ignore important political realities of their day and rule based on ideological or theoretical leanings. Conversely, it will show that both theories lead to constructive results when the presiding judges take political realties into account and consider the consequences of their rulings. Thus, the main argument of this paper is that political realities should never be divorced from judicial rulings. This analysis will also show that the political process is integral to sound jurisprudence, and that the constitutional framers left room for this in the way they wrote our most sacred document