Information Geometry and Phase Transitions

The introduction of a metric onto the space of parameters in models in Statistical Mechanics and beyond gives an alternative perspective on their phase structure. In such a geometrization, the scalar curvature, R, plays a central role. A non-interacting model has a flat geometry (R=0), while R diverges at the critical point of an interacting one. Here, the information geometry is studied for a number of solvable statistical-mechanical models.Comment: 6 pages with 1 figur

Acute toxicity of metasystox to wedge clam, Donax cuneatus from west coast

96h acute toxicity tests were performed using commercial grade metasystox on the marine wedge clam, Donax cuneatus during summer 1985. The behaviour and mortality rates were recorded periodically. Most of the dams responded in opening the shell valves and extending the siphons quicker in low test concentrations (0.004-0.0052 p.p.m) but this was slow and late in high concentrations (0.0056-0.008 p.p.m). Mortality began to occur in 0.008 p.p.m. from 12 h, whereas, in 0.0052 p.p.m. from 60 h onwards. The observed LC sub(0) value was 0.004 p.p.m. and LC sub(50) 0.0064 p.p.m. The regression equation established was Y = 79.0891 + 33.4523 X. The rate of oxygen concentration increased at LC sub(0) and LC sub(50) values compared to control indicating the disturbed physiological adjustment. The results are correlated with physico-chemical parameters of seawater and discussed in the light of pesticide toxicity to the dam

Complexation of Plutonium (IV) With Sulfate At Variable Temperatures

The complexation of plutonium(IV) with sulfate at variable temperatures has been investigated by solvent extraction method. A NaBrO{sub 3} solution was used as holding oxidant to maintain the plutonium(IV) oxidation state throughout the experiments. The distribution ratio of Pu(IV) between the organic and aqueous phases was found to decrease as the concentrations of sulfate were increased. Stability constants of the 1:1 and 1:2 Pu(IV)-HSO{sub 4}{sup -} complexes, dominant in the aqueous phase, were calculated from the effect of [HSO{sub 4}{sup -}] on the distribution ratio. The enthalpy and entropy of complexation were calculated from the stability constants at different temperatures using the Van't Hoff equation

Magnetothermal conductivity of Ba1-xKxBiO3 crystals

We have investigated the thermal conductivity of single-crystal Ba1-xKxBiO3 (BKBO). The measured temperature and field dependences reveal that both electrons and phonons contribute to the thermal conduction of BKBO in both the normal and the superconducting states, and that the phonon mean free path can be manipulated by potassium doping concentration. The potassium-underdoped samples exhibit a suppression of phonon diffusivity, and consequently a more pronounced electronic contribution, indicating that the statistical fluctuation of potassium concentration may lead to an increase of defect density. The field-dependent thermal conductivity of BKBO in the superconducting state exhibits scaling behavior, which indicates the presence of an unconventional superconducting gap

Photoconductance Quantization in a Single-Photon Detector

We have made a single-photon detector that relies on photoconductive gain in a narrow electron channel in an AlGaAs/GaAs 2-dimensional electron gas. Given that the electron channel is 1-dimensional, the photo-induced conductance has plateaus at multiples of the quantum conductance 2e$^{2}$/h. Super-imposed on these broad conductance plateaus are many sharp, small, conductance steps associated with single-photon absorption events that produce individual photo-carriers. This type of photoconductive detector could measure a single photon, while safely storing and protecting the spin degree of freedom of its photo-carrier. This function is valuable for a quantum repeater that would allow very long distance teleportation of quantum information.Comment: 4 pages, 4 figure

Fluorescent carbon dioxide indicators

Over the last decade, fluorescence has become the dominant tool in biotechnology and medical imaging. These exciting advances have been underpinned by the advances in time-resolved techniques and instrumentation, probe design, chemical / biochemical sensing, coupled with our furthered knowledge in biology. Complementary volumes 9 and 10, Advanced Concepts of Fluorescence Sensing: Small Molecule Sensing and Advanced Concepts of Fluorescence Sensing: Macromolecular Sensing, aim to summarize the current state of the art in fluorescent sensing. For this reason, Drs. Geddes and Lakowicz have invited chapters, encompassing a broad range of fluorescence sensing techniques. Some chapters deal with small molecule sensors, such as for anions, cations, and CO2, while others summarize recent advances in protein-based and macromolecular sensors. The Editors have, however, not included DNA or RNA based sensing in this volume, as this were reviewed in Volume 7 and is to be the subject of a more detailed volume in the near future

Expression of Luteinizing Hormone Receptor in the Gastrointestinal Tract in Patients with and without Dysmotility

Leuprolide is a gonadotropin-releasing hormone (GnRH) analog which has been shown to reduce symptoms in patients with irritable bowel syndrome (IBS) and chronic intestinal pseudo-obstruction (CIPO). The mechanism is not known, but one hypothesis is through down-modulation of luteinizing hormone (LH) secretion, a hormone whith antagonistic effect on gastrointestinal motility. However, presence of LH receptors in the gastrointestinal tract has never been described. The aim of this study was to find one possible way of action for leuprolide by examining the presence of the LH receptor, and if present, to see whether there was different expression in patients with or without dysmotility. Full-thickness biopsies from the bowel wall of patients with and without severe dysmotility were examined using immunohistochemistry staining. Biopsies showed expression of LH receptors on myenteric neurons and in glial cells, neutrophils, endothelial cells and mast cells. There was no difference in expression between patient groups