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

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

Reimagining teacher professional development : communities of practice

Communities of practice (COP) are groups of people who share a concern or passion for something they do, and learn how to do it better as they interact regularly. The presentation broadly covers how to facilitate new learning methods through teacher forums as a community of practice in India

Bypass grafting operations using conventional technique with off-pump coronary artery bypass grafting in two identical groups conducted at the Penang Hospital (1999-2000)

This is a prospective study conducted at the Department of Cardiothoracic Surgery, Penang Hospital, Penang, with a total of one hundred patients were studied over a period of one year between January 1999 to January 2000. Fifty patients who had undergone coronary artery bypass surgery off-pump (OPCAB) were compared with fifty patients who had undergone coronary artery bypass surgery on the heart-lung machine (CPB). Patients who had associated problems of renal failure, stroke, bronchial asthma and recent myocardial infarction were included in the off-pump CABG surgery. The symptoms did not differ in both the groups. They had experienced angina, decreased effort tolerance, palpitations, with NYHA class IT, ill and IV. The predisposing factors of diabetes mellitus, hypertension, hyperlipidemia, smoking, previous family history of heart disease were studied in both these groups. The same pre-operative investigations were performed in both groups of patients. Chest x-ray, ECG, echocardiography, femoral angiogram were done for these one hundred patients. The intra-and post operative bleeding, pre and post operative renal status, echocardiogram, ECG and chest X-rays were compared. The cost effectiveness of both the OPCAB and CPB procedures were reviewed. There was, generally, a better outcome in patients who had undergone a coronary bypass by the offpump (OPCAB) method as when compared to those by the CPB method. This indicates that more cases can be done by the OPCAB method in the future

POWER SYSTEM FAULT DETECTION AND CLASSIFICATION BY WAVELET TRANSFORMS AND ADAPTIVE RESONANCE THEORY NEURAL NETWORKS

This thesis aims at detecting and classifying the power system transmission line faults. To deal with the problem of an extremely large data set with different fault situations, a three step optimized Neural Network approach has been proposed. The approach utilizes Discrete Wavelet Transform for detection and two different types of self-organized, unsupervised Adaptive Resonance Theory Neural Networks for classification. The fault scenarios are simulated using Alternate Transients Program and the performance of this highly improved scheme is compared with the existing techniques. The simulation results prove that the proposed technique handles large data more efficiently and time of operation is considerably less when compared to the existing methods

Reimagining teacher professional development : communities of practice

Communities of practice (COP) are groups of people who share a concern or passion for something they do, and learn how to do it better as they interact regularly. The presentation broadly covers how to facilitate new learning methods through teacher forums as a community of practice in India

Interplay of antiferromagnetism, ferromagnetism and superconductivity in EuFe_2(As_1-xP_x)_2 single crystals

We report a systematic study on the influence of antiferromagnetic and ferromagnetic phases of Eu^2+ moments on the superconducting phase upon doping the As site by isovalent P, which acts as chemical pressure on EuFe_2As_2. Bulk superconductivity with transition temperatures of 22 K and 28 K are observed for x=0.16 and 0.20 samples respectively. The Eu ions order antiferromagnetically for x=0.22 whereupon the Eu ions order ferromagnetically. Density functional theory based calculations reproduce the observed experimental findings consistently. We discuss in detail the coexistence of superconductivity and magnetism in a tiny region of the phase space and comment on the competition of ferromagnetism and superconductivity in the title compound.Comment: 6 pages, 5 figures, 1 tabl

Violence and the Society

"Fakulti Perubatan, Rabu, 16 Julai 2003.

SmO thin films: a flexible route to correlated flat bands with nontrivial topology

Using density functional theory based calculations, we show that the correlated mixed-valent compound SmO is a 3D strongly topological semi-metal as a result of a 4$f$-5$d$ band inversion at the X point. The [001] surface Bloch spectral density reveals two weakly interacting Dirac cones that are quasi-degenerate at the M_bar-point and another single Dirac cone at the Gamma_bar-point. We also show that the topological non-triviality in SmO is very robust and prevails for a wide range of lattice parameters, making it an ideal candidate to investigate topological nontrivial correlated flat bands in thin-film form. Moreover, the electron filling is tunable by strain. In addition, we find conditions for which the inversion is of the 4f-6s type, making SmO to be a rather unique system. The similarities of the crystal symmetry and the lattice constant of SmO to the well studied ferromagnetic semiconductor EuO, makes SmO/EuO thin film interfaces an excellent contender towards realizing the quantum anomalous Hall effect in a strongly correlated electron system.Comment: Paper+supplemen