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

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

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

The City by the Pool

This volume offers a new and up-to-date synthesis of Lincoln's long history as a major city and regional capital, from prehistory to 1945. The 'City by the Pool' was a major religious centre long before the Roman invasion and from bronze-age shamans to early Baptists people have always been attracted here for spiritual as well as mundane purposes. The authors argue for the presence of a major ritual causeway of the late Bronze and Iron Age and outline the extent to which ritual monuments also contributed to the character of Roman Lincoln. This book is based on more than a hundred publicly-funded excavations and building surveys undertaken between 1945 and 2000. It surveys all aspects of city life, from housing and fortifications to the water supply and rubbish disposal. It includes a CD Rom with a Geographic Information System (GIS) and a relational data-base known as LARA (the Lincoln Archaeological Research Assessment)