Formation of small-scale structure in SUSY CDM

The lightest supersymmetric particle, most likely the lightest neutralino, is one of the most prominent particle candidates for cold dark matter (CDM). We show that the primordial spectrum of density fluctuations in neutralino CDM has a sharp cut-off, induced by two different damping mechanisms. During the kinetic decoupling of neutralinos, non-equilibrium processes constitute viscosity effects, which damp or even absorb density perturbations in CDM. After the last scattering of neutralinos, free streaming induces neutralino flows from overdense to underdense regions of space. Both damping mechanisms together define a minimal mass scale for perturbations in neutralino CDM, before the inhomogeneities enter the nonlinear epoch of structure formation. We find that the very first gravitationally bound neutralino clouds ought to have masses above 10^{-6} solar masses, which is six orders of magnitude above the mass of possible axion miniclusters.Comment: 7 pages, 3 figures, to appear in proceedings of "IDM 2002, 4th International Workshop on the Identification of Dark Matter

Applications of high pressure differential scanning calorimetry to aviation fuel thermal stability research

High pressure differential scanning calorimetry (DSC) was studied as an alternate method for performing high temperature fuel thermal stability research. The DSC was used to measure the heat of reaction versus temperature of a fuel sample heated at a programmed rate in an oxygen pressurized cell. Pure hydrocarbons and model fuels were studied using typical DSC operating conditions of 600 psig of oxygen and a temperature range from ambient to 500 C. The DSC oxidation onset temperature was determined and was used to rate the fuels on thermal stability. Kinetic rate constants were determined for the global initial oxidation reaction. Fuel deposit formation is measured, and the high temperature volatility of some tetralin deposits is studied by thermogravimetric analysis. Gas chromatography and mass spectrometry are used to study the chemical composition of some DSC stressed fuels

Filtering Interpolators for Image Comparison Algorithms

Comparing two or more images, either by differencing or ratioing, is important to many remote sensing problems. Because the pixel sample points for the images are (almost) always separated by some nonzero shift, a resampling, or interpolation, process must be performed if one image is to be accurately compared to another. Considered in Fourier space, an interpolator acts as a filter that attenuates some frequencies (usually high) of the image. Thus, when the shifted and unshifted images are compared, the former has been filtered, while the latter has not; the effect of this difference is called interpolation error. The key idea of this paper is to apply a filter to the unshifted image that matches the filtering effect of applying the interpolator to the shifted image, thereby drastically reducing interpolation error. The resulting interpolators, called filtering interpolators, are derived and discussed in detail elsewhere. Basic results will be given in this presentation

Application of ribotyping and IS<i>200</i> fingerprinting to distinguish the five <i>Salmonella</i> serotype O6,7:c:1,5 groups: Choleraesuis <i>sensu stricto</i>, Choleraesuis var. Kunzendorf, Choleraesuis var. Decatur, Paratyphi C, and Typhisuis

Sixty-seven strains of the five described Salmonella serotypes having antigens 6,7:c: 1,5, that is S. enterica serotype Choleraesuis sensu stricto, Choleraesuis var. Kunzendorf, Choleraesuis var. Decatur, Paratyphi C, and Typhisuis, were examined for 16S rrn profile ribotype, presence of IS200 and phenotypic characters, including rate of change of flagellar-antigen phase and nutritional character. Choleraesuis sensu stricto and its Kunzendorf variant had related but distinct ribotypes. Therefore, ribotyping appears to be a suitable method for differentiating Choleraesuis non-Kunzendorf from Choleraesuis var. Kunzendorf. Some strains of Paratyphi C had 16S profiles that resembled that of Choleraesuis non-Kunzendorf, while others resembled that of Choleraesuis var. Kunzendorf. The Typhisuis profiles were like those of Choleraesuis non-Kunzendorf, while the Choleraesuis var. Decatur profiles were unlike those of any of the other four groups. Furthermore, IS200 fingerprinting discriminated between Choleraesuis var. Decatur and the other strains with antigenic formula O6,7:c: 1,5, and comparison of IS200 patterns showed a high degree of genetic divergence within Choleraesuis var. Decatur. Our findings show that ribotyping and IS200 fingerprinting, combined with classical microbiological methods, distinguish the groups Choleraesuis non-Kunzendorf, Choleraesuis var. Kunzendorf, Choleraesuis var. Decatur, Paratyphi C and Typhisuis

Reliability of Chronically Recorded Visually Evoked Potentials in Awake Mouse Visual Cortex: Effect of Restraint Habituation

Visual function in mice can be quantified using electrophysiological methods. This can be done using chronically implanted electrodes that record visually evoked potentials (VEPs) from a population of neurons in the primary visual cortex (V1) in order to estimate visual acuity. The inherently noisy environment of the brain presents a challenge, as the VEP signal is very small. Our goal is to optimize VEP recording procedures to produce the highest signal-to-noise ratio possible by investigating the role of restraint habituation. The approach we designed included three experimental groups: one in which the animals received regular stimulus exposure and no habituation, one in which the animals received 10 days of restraint habituation prior to 10 days of stimulus exposure, and one in which the animals received habituation only and no stimulus exposure. We found that restraint habituation is necessary in order to produce reliable VEPs. Furthermore, we discovered that over time there is an increase in VEP amplitude that is dependent upon visual experience. This experience-dependent effect is driven by repeated exposure to specific stimuli

Keeper : a novel and critical reflection on historical fiction as a genre

Previously held under moratorium from 11 February 2019 until 20 April 2022.This practice-led PhD thesis consists of two sections: a creative element and critical commentary. ‘Keeper’ is a historical crime fiction novel. Set in the slums of Regency London, the story is about the effects of trauma on the individual, and gentrification on the community. It looks at what family means for different people, and how the ties of blood and friendship are tested. Both third-person and first-person focalisation are employed, as the story is told from two different perspectives – one that of an injured soldier who is relatively new to the rookery, and the other an orphaned girl who has never seen the world beyond it. The third-person voice is connected to and often overwhelmed by the past, and this is reflected in the use of the past tense, which contrasts with the immediacy of first-person present tense. The narrative utilises the investigation of a murder to scrutinise the development of British society in the early nineteenth century, through a fictional examination of historical events and their social consequences. An author’s note provides insight into the research process. The critical commentary explores the origins and theoretical response to the historical novel. The commentary touches on the nineteenth century split between academic history and historical fiction, which promoted an artificial opposition between history and fiction, and discusses the lack of scholarly definitions of the genre. Issues surrounding the classifications that are available are examined, before a new definition is proposed. The practical challenges of the historical novel are explored through interviews with six authors of historical fiction. An analysis of these interview transcripts and Hilary Mantel’s Reith Lectures is used to argue that the writers’ approach to research, and engagement with sources, demonstrates a working methodology from which aspiring writers may learn.This practice-led PhD thesis consists of two sections: a creative element and critical commentary. ‘Keeper’ is a historical crime fiction novel. Set in the slums of Regency London, the story is about the effects of trauma on the individual, and gentrification on the community. It looks at what family means for different people, and how the ties of blood and friendship are tested. Both third-person and first-person focalisation are employed, as the story is told from two different perspectives – one that of an injured soldier who is relatively new to the rookery, and the other an orphaned girl who has never seen the world beyond it. The third-person voice is connected to and often overwhelmed by the past, and this is reflected in the use of the past tense, which contrasts with the immediacy of first-person present tense. The narrative utilises the investigation of a murder to scrutinise the development of British society in the early nineteenth century, through a fictional examination of historical events and their social consequences. An author’s note provides insight into the research process. The critical commentary explores the origins and theoretical response to the historical novel. The commentary touches on the nineteenth century split between academic history and historical fiction, which promoted an artificial opposition between history and fiction, and discusses the lack of scholarly definitions of the genre. Issues surrounding the classifications that are available are examined, before a new definition is proposed. The practical challenges of the historical novel are explored through interviews with six authors of historical fiction. An analysis of these interview transcripts and Hilary Mantel’s Reith Lectures is used to argue that the writers’ approach to research, and engagement with sources, demonstrates a working methodology from which aspiring writers may learn

Aerodynamic performance of conventional and advanced design labyrinth seals with solid-smooth abradable, and honeycomb lands

Labyrinth air seal static and dynamic performance was evaluated using solid, abradable, and honeycomb lands with standard and advanced seal designs. The effects on leakage of land surface roughness, abradable land porosity, rub grooves in abradable lands, and honeycomb land cell size and depth were studied using a standard labyrinth seal. The effects of rotation on the optimum seal knife pitch were also investigated. Selected geometric and aerodynamic parameters for an advanced seal design were evaluated to derive an optimized performance configuration. The rotational energy requirements were also measured to determine the inherent friction and pumping energy absorbed by the various seal knife and land configurations tested in order to properly assess the net seal system performance level. Results indicate that: (1) seal leakage can be significantly affected with honeycomb or abradable lands; (2) rotational energy absorption does not vary significantly with the use of a solid-smooth, an abradable, or a honeycomb land; and (3) optimization of an advanced lab seal design produced a configuration that had leakage 25% below a conventional stepped seal

An investigation into linearity with cumulative emissions of the climate and carbon cycle response in HadCM3LC

We investigate the extent to which global mean temperature, precipitation, and the carbon cycle are constrained by cumulative carbon emissions throughout four experiments with a fully coupled climate-carbon cycle model. The two paired experiments adopt contrasting, idealised approaches to climate change mitigation at different action points this century, with total emissions exceeding two trillion tonnes of carbon in the later pair. Their initially diverging cumulative emissions trajectories cross after several decades, before diverging again. We find that their global mean temperatures are, to first order, linear with cumulative emissions, though regional differences in temperature of up to 1.5K exist when cumulative emissions of each pair coincide. Interestingly, although the oceanic precipitation response scales with cumulative emissions, the global precipitation response does not, due to a decrease in precipitation over land above cumulative emissions of around one trillion tonnes of carbon (TtC). Most carbon fluxes and stores are less well constrained by cumulative emissions as they reach two trillion tonnes. The opposing mitigation approaches have different consequences for the Amazon rainforest, which affects the linearity with which the carbon cycle responds to cumulative emissions. Averaged over the two fixed-emissions experiments, the transient response to cumulative carbon emissions (TCRE) is 1.95 K TtC-1, at the upper end of the IPCC’s range of 0.8-2.5 K TtC-1