4,344 research outputs found

    Pressure-driven magnetic moment collapse in the ground state of MnO

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    The zero temperature Mott transition region in antiferromagnetic, spin S=5/2 MnO is probed using the correlated band theory LSDA+U method. The first transition encountered is an insulator-insulator volume collapse within the rocksalt structure that is characterized by an unexpected Hund's rule violating `spin-flip' moment collapse. This spin-flip to S=1/2 takes fullest advantage of the anisotropy of the Coulomb repulsion, allowing gain in the kinetic energy (which increases with decreasing volume) while retaining a sizable amount of the magnetic exchange energy. While transition pressures vary with the interaction strength, the spin-flip state is robust over a range of interaction strengths and for both B1 and B8 structures

    Association of Small Dense LDL with Coronary Artery Disease and Diabetes in Urban Asian Indians - The Chennai Urban Rural Epidemiology Study (CURES-8)

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    Objective: Earlier studies in Europeans have identified small dense LDL to be associated with coronary artery disease and diabetes. In this study we assessed the association of small dense LDL with diabetes and CAD in Asian Indians. Methods: Study subjects were selected from the Chennai Urban Rural Epidemiology Study (CURES), a population based study on representative sample of Chennai city in southern India. Group 1:non-diabetic subjects (n=30); Group 2: diabetic subjects without CAD (n=30); Group 3:diabetic subjects with CAD (n=30). LDL subfractions were estimated using LipoPrint LDL system. LDL subfractions 3 and above, defined as small dense LDL was summed up to determine the overall small LDL. 75th percentile of the overall small dense LDL in non-diabetic subjects was used as a cut-off for defining elevated levels of small dense LDL. Results: The mean age of the study subjects was not significantly different among groups. Overall small dense LDL was significantly higher in diabetic subjects with CAD (16.7 ± 11.1 mg/dl, p<0.05) and without CAD (11.1 ± 8.0 mg/dl, p<0.05) compared to non-diabetic subjects without CAD (7.2 ± 6.8 mg/dl). Small dense LDL showed a positive correlation with fasting plasma glucose (r=0.252, p=0.023), HbA1c (r=0.281, p=0.012), total cholesterol (r=0.443, p<0.001), triglycerides(r=0.685, p<0.001), LDL(r=0.342, p=0.002), total cholesterol/HDL ratio (r=0.660, p=<0.001) and triglycerides/HDL ratio(r=0.728, p<0.001) and a negative correlation with HDL cholesterol (r= -0.341, p=0.002) and QUICKI values (r= -0.260, p=0.019). ROC curves constructed to predict elevated small dense LDL ((9.0 mg/dl) revealed that triglycerides/HDL ratio and total cholesterol/HDL ratio had higher AUC values compared to other parameters. A triglycerides/HDL ratio of 3.0 had the optimum sensitivity (80.0%) and specificity (78.0%) for detecting elevated small dense LDL. Conclusion: This data suggests that in Asian Indians, small dense LDL is associated with both diabetes and CAD and that a triglycerides/HDL ratio (3.0 could serve a surrogate marker of small dense LDL

    Forecasting Stock Time-Series using Data Approximation and Pattern Sequence Similarity

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    Time series analysis is the process of building a model using statistical techniques to represent characteristics of time series data. Processing and forecasting huge time series data is a challenging task. This paper presents Approximation and Prediction of Stock Time-series data (APST), which is a two step approach to predict the direction of change of stock price indices. First, performs data approximation by using the technique called Multilevel Segment Mean (MSM). In second phase, prediction is performed for the approximated data using Euclidian distance and Nearest-Neighbour technique. The computational cost of data approximation is O(n ni) and computational cost of prediction task is O(m |NN|). Thus, the accuracy and the time required for prediction in the proposed method is comparatively efficient than the existing Label Based Forecasting (LBF) method [1].Comment: 11 page

    Electrochromic device response controlled by an in situ polymerized ionic liquid based gel electrolyte

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    Polymer electrolytes were synthesized by two different approaches and applied to electrochromic devices based on electrodeposited tungsten oxide (WO3) or poly(3,4-ethylenedioxythiophene) (PEDOT) films as the cathode, and a Prussian blue (PB) film as the anode. The first method involved the entrapping of an ionic liquid in a polymer host (poly(methylmethacrylate) or PMMA) and the second approach relied on the in situ thermal polymerization of methylmethacrylate (MMA) in the hydrophobic ionic liquid, yielding a solidified transparent gel. The effect of in situ solid polymer electrolyte formation on device performance characteristics was realized in terms of a larger coloration efficiency of 119 cm2 C21 (l = 550 nm) achieved for the WO3–PB (MMA) device, as compared to a value of 54 cm2 C21 obtained for the WO3–PB (PMMA) device. Similar enhancements in electrochromic coloring efficiency, reflectance contrast, and faster switching kinetics were obtained for the PEDOT–PB (MMA) device. The strategy of introducing an electrolyte to the electrochromic device in a liquid state and then subjecting the same to gradual polymerization allows greater accessibility of the electrolyte ions to the active sites on the electrochromic electrodes and superior interfacial contact. As a consequence, larger optical contrast and faster kinetics are achieved in the MMA based devices. While PEDOT films were amorphous, PB films were semi-crystalline but only in the case of WO3; the hexagonal structure of WO3, equipped with three/four/six-coordinated voids was found to affect bleaching kinetics favorably. The performance of PMMA based electrolyte is limited by high resistance at the electrode–electrolyte interface, and a smaller number of ions available for oxidation and reduction. Large area (y10 cm 6 4 cm) devices were also fabricated using this simple wet chemistry method and their ability to color uniformly without any pinholes was demonstrated
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