2,204 research outputs found

    The role of price expectations in the UK housing market

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    Copyright University of HertfordshireThe objective of this paper is to explain and derive the non-linear, S-shaped diffusion path of price expectations and provide a forecasting model, three months ahead with the implications assessed. Bounded rationality means that various agents in the U.K. housing market, such as buyers,sellers, estate agents and chartered surveyors, play differing rôles in the overall formulation of expectations of prices. This is analogous to the logistic effect with a diffusion path of dis-equilibrium to the end-point of equilibrium. The empirical analysis makes use of the forwarding-looking price expectations data published by Royal Institution of Chartered Surveyors (RICS) with the actual observations produced by Mortgage lenders, the Halifax and the Nationwide

    Annona muricata (graviola): toxic or therapeutic

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    This paper examines annona muricata (graviola): toxic or therapeutic

    Two level anti-crossings high up in the single-particle energy spectrum of a quantum dot

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    We study the evolution with magnetic field of the single-particle energy levels high up in the energy spectrum of one dot as probed by the ground state of the adjacent dot in a weakly coupled vertical quantum dot molecule. We find that the observed spectrum is generally well accounted for by the calculated spectrum for a two-dimensional elliptical parabolic confining potential, except in several regions where two or more single-particle levels approach each other. We focus on two two-level crossing regions which show unexpected anti-crossing behavior and contrasting current dependences. Within a simple coherent level mixing picture, we can model the current carried through the coupled states of the probed dot provided the intrinsic variation with magnetic field of the current through the states (as if they were uncoupled) is accounted for by an appropriate interpolation scheme.Comment: 4 pages, 4 figures, accepted for publication in Physica E in MSS 13 conference proceeding

    Chemical and mineralogical characterization of Gidan Jaja iron ore, Zamfara State, Nigeria

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    The chemical and mineralogical characteristics of Gidan Jaja iron ore located in Zurmi Local Governmental Area of Zamfara State was carried out using X-ray Fluorescence (XRF) spectrometer, X-ray Diffractometer (XRD), Scanning Electron Microscope (SEM) and Optical Microscope. The XRF results obtained revealed that Gidan Jaja Iron ore has an average content of 73.79 % Fe2O3, 0.52 % MnO, 17.50 % TiO2, 0.11 % CaO, 0.50 % Cr2O3, 3.84 % SiO2, 0.43 % Al2O3, 0.034 % CuO, 0.02 % NiO, 0.46 % PbO, 2.76 % LOI. Phosphorus and Sulphur were below limit of detection. XRD analysis revealed that the ore contained 56 % Ilmenite, 34 % Magnetite and 10 % Spinel minerals. Petrographic study using polarized light revealed that the iron bearing minerals are predominantly Ilmenite and Magnetite, with minor amount of hematite, spinel and quartz. The results obtained from SEM analysis showed that the iron bearing minerals are separated from other minerals in the ore by smooth grain boundaries. The quality of the ore was compared with ores from other part of Nigeria, and based on the results obtained in this research work, Gidan Jaja iron ore can be classified as high grade, low silica, ilmenite iron ore. Finally combined results from chemical and mineralogical characterization of the iron ore deposit indicated that, the iron ore can be a source of iron ore for use in iron production.Keywords: Chemical, Mineralogical, Characterization, Gidan Jaja, Iron or

    Computing with Membranes and Picture Arrays

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    Splicing systems were introduced by Tom Head [3] on biological considerations to model certain recombinant behaviour of DNA molecules. An effective extension of this operation to images was introduced by Helen Chandra et al. [5] and H array splicing systems were considered. A new method of applying the splicing operation on images of hexagonal arrays was introduced by Thomas et al. [12] and generated a new class of hexagonal array languages HASSL. On the other hand, P systems, introduced by Paun [6] generating rectangular arrays and hexagonal arrays have been studied in the literature, bringing together the two areas of theoretical computer science namely membrane computing and picture languages. P system with array objects and parallel splicing operation on arrays is introduced as a simple and effective extension of P system with operation of splicing on strings and this new class of array languages is compared with the existing families of array languages. Also we propose another P system with hexagonal array objects and parallel splicing operation on hexagonal arrays is introduced and this new class of hexagonal array languages is compared with the existing families of hexagonal array languages

    Liver fat in adults with GH deficiency: comparison to matched controls and the effect of GH replacement

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    CONTEXT: Existing data regarding the association between growth hormone deficiency (GHD) and liver fat content are conflicting. OBJECTIVE: We aimed i) to assess intrahepatocellular lipid (IHCL) content in hypopituitary adults with GHD compared to matched controls and ii) to evaluate the effect of growth hormone (GH) replacement on IHCL content. DESIGN: Cross-sectional comparison and controlled intervention study. PATIENTS, PARTICIPANTS: Cross-sectional comparison: 22 hypopituitary adults with GHD and 44 healthy controls matched for age, BMI, gender and ethnicity. Intervention study: 9 GHD patients starting GH replacement (GH Rx group), 9 GHD patients not starting replacement therapy (non-GH Rx group). INTERVENTION: Intervention study:GH replacement for 6 months in the GH Rx group, dosage was titrated to achieve normal IGF-1 levels. MAIN OUTCOME MEASURES: IHCL content determined by proton magnetic resonance spectroscopy (1 H MRS). RESULTS: Cross-sectional comparison: There was no difference in IHCL content between GHD patients and healthy controls (1.89% (0.30, 4.03) vs. 1.14% (0.22, 2.32); p=0.2), the prevalence of patients with hepatic steatosis (IHCL of ≥ 5.56%) was similar in the two groups (22.7% vs. 15.9%; chi square probability = 0.4). Intervention study: The change in IHCL content over 6 months did not differ between the GH Rx group and the non-GH Rx group (-0.63 ± 4.53% vs. +0.11 ± 1.46%; p=0.6). CONCLUSIONS: In our study liver fat content and the prevalence of hepatic steatosis did not differ between hypopituitary adults with GHD and matched controls. In GHD patients GH replacement had no effect on liver fat content

    Interaction of CO2 laser-modified nylon with osteoblast cells in relation to wettability

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    It has been amply demonstrated previously that CO2 lasers hold the ability to surface modify various polymers. In addition, it has been observed that these surface enhancements can augment the biomimetic nature of the laser irradiated materials. This research has employed a CO2 laser marker to produce trench and hatch topographical patterns with peak heights of around 1 μm on the surface of nylon 6,6. The patterns generated have been analysed using white light interferometery, optical microscopy and X-ray photoelectron spectroscopy was employed to determine the surface oxygen content. Contact angle measurements were used to characterize each sample in terms of wettability. Generally, it was seen that as a result of laser processing the contact angle, surface roughness and surface oxygen content increased whilst the apparent polar and total surface energies decreased. The increase in contact angle and reduction in surface energy components was found to be on account of a mixed intermediate state wetting regime owing to the change in roughness due to the induced topographical patterns. To determine the biomimetic nature of the modified and as-received control samples each one was seeded with 2×104 cells/ml normal human osteoblast cells and observed after periods of 24 hours and 4 days using optical microscopy and SEM to determine mean cell cover densities and variations in cell morphology. In addition a haeymocytometer was used to show that the cell count for the laser patterned samples had increased by up to a factor of 1.5 compared to the as-received control sample after 4 days of incubation. Significantly, it was determined that all laser-induced patterns gave rise to better cell response in comparison to the as-received control sample studied due to increased preferential cell growth on those surfaces with increased surface roughness

    Quantification of hepatic steatosis with 3-T MR imaging: Validation in ob/ob mice

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    Purpose: To validate quantitative imaging techniques used to detect and measure steatosis with magnetic resonance (MR) imaging in an ob/ob mouse model of hepatic steatosis. Materials and Methods: The internal research animal and resource center approved this study. Twenty-eight male ob/ob mice in progressively increasing age groups underwent imaging and were subsequently sacrificed. Six ob /+ mice served as control animals. Fat fraction imaging was performed with a chemical shift-based water-fat separation method. The following three methods of conventional fat quantification were compared with imaging: lipid extraction and qualitative and quantitative histologic analysis. Fat fraction images were reconstructed with single- and multiple-peak spectral models of fat and with and without correction for T2* effects. Fat fraction measurements obtained with the different reconstruction methods were compared with the three methods of fat quantification, and linear regression analysis and two-sided and two-sample t tests were performed. Results:Lipid extraction and qualitative and quantitative histologic analysis were highly correlated with the results of fat fraction imaging (r2 = 0.92, 0.87, 0.82, respectively). No significant differences were found between imaging measurements and lipid extraction (P = .06) or quantitative histologic (P = .07) measurements when multiple peaks of fat and T2* correction were included in image reconstruction. Reconstructions in which T2* correction, accurate spectral modeling, or both were excluded yielded lower agreement when compared with the results yielded by other techniques. Imaging measurements correlated particularly well with histologic grades in mice with low fat fractions (intercept, -1.0% ± 1.2 [standard deviation ]). Conclusion: MR imaging can be used to accurately quantify fat in vivo in an animal model of hepatic steatosis and may serve as a quantitative biomarker of hepatic steatosis. © RSNA, 2010
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