NMR Determination of an Incommensurate Helical Antiferromagnetic Structure in EuCo2As2

We report $^{153}$Eu, $^{75}$As and $^{59}$Co nuclear magnetic resonance (NMR) results on EuCo$_2$As$_2$ single crystal. Observations of $^{153}$Eu and $^{75}$As NMR spectra in zero magnetic field at 4.3 K below an antiferromagnetic (AFM) ordering temperature $T_{\rm N}$ = 45 K and its external magnetic field dependence clearly evidence an incommensurate helical AFM structure in EuCo$_2$As$_2$. Furthermore, based on $^{59}$Co NMR data in both the paramagnetic and the incommensurate AFM states, we have determined the model-independent value of the AFM propagation vector ${\bf k}$ = (0, 0, 0.73 $\pm$ 0.07)2$\pi$/$c$ where $c$ is the $c$ lattice parameter. Thus the incommensurate helical AFM state was characterized by only NMR data with model-independent analyses, showing NMR to be a unique tool for determination of the spin structure in incommensurate helical AFMs.Comment: 6 pages, 4 figures, accepted for publication in Phys.Rev.

Factors Determining Capital Structure: A Case study of listed companies in Sri Lanka

The most debatable topic in capital structure revolves around the optimal capital structure. This article investigates the factors determining capital structure in Sri Lankan context during 2002 to 2006 (five years). In an attempt, the present study examined the determinants of capital structure such as tangibility, size, growth rate, profitability, liquidity and dividend payout with samples of 50 companies including 13 sectors representing 21% of the mean number of companies listed in Colombo Stock Exchange Ltd as of 2006. Descriptive and inferential statistics were used in the analysis of data using Statistical Package for Social Science (SPSS). Results revealed that the use of debt capital is relatively low in Sri Lanka and size, growth rate and profitability are statistically significant determinants of capital structure. According to regression analysis, above six factors have an impact on capital structure at the rate of 77 % which is significant at 0.05 levels. Keywords: Capital Structure, Determinant(s), Colombo Stock Exchange.

EuCo2P2: A Model Molecular-Field Helical Heisenberg Antiferromagnet

The metallic compound EuCo2P2 with the body-centered tetragonal ThCr2Si2 structure containing Eu spins 7/2 was previously shown from single-crystal neutron diffraction measurements to exhibit a helical antiferromagnetic (AFM) structure below TN = 66.5 K with the helix axis along the c axis and with the ordered moments aligned within the ab-plane. Here we report crystallography, electrical resistivity, heat capacity, magnetization and magnetic susceptibility measurements on single crystals of this compound. We demonstrate that EuCo2P2 is a model molecular-field helical Heisenberg antiferromagnet from comparisons of the anisotropic magnetic susceptibility chi, high-field magnetization and magnetic heat capacity of EuCo2P2 single crystals at temperature T < TN with the predictions of our recent formulation of molecular field theory. Values of the Heisenberg exchange interactions between the Eu spins are derived from the data. The low-T magnetic heat capacity ~ T^3 arising from spin-wave excitations with no anisotropy gap is calculated and found to be comparable to the lattice heat capacity. The density of states at the Fermi energy of EuCo2P2 and the related compound BaCo2P2 are found from the heat capacity data to be large, 10 and 16 states/eV per formula unit for EuCo2P2 and BaCo2P2, respectively. These values are enhanced by a factor of ~2.5 above those found from DFT electronic structure calculations for the two compounds. The calculations also find ferromagnetic Eu-Eu exchange interactions within the ab-plane and AFM interactions between nearest- and next-nearest planes, in agreement with the MFT analysis of chi{ab}(T < TN).Comment: 20 pages, 17 figures, 3 tables, 46 references. This is an extended replacement of arXiv:1512.02958 with an additional coautho

Damage Assessment Software Program

The software package described here deals with the assessment of damage inflicted by missiles carrying pre-fragmented, bomblet, incendiary, runway-denial penetration submunition (RDPS), smart munition, and terminallyguided submunition warhead. The targets to be neutralised could be static, semistatic or mobile, like runways,bridges, bunkers, armoured tanks, soft-skinned vehicles, and personnel. This is graphical user interface(GUI)-based software, where the user can specify the target dimensions, target types, the number of missiles, its aimpoint, the type of warhead and the mode of operation. The software gives the number of targets that have beenneutralised effectively, as the output. This GUI-based software has been developed using Microsoft Visual Basic,Version 6.0.Defence Science Journal, 2008, 58(6), pp.745-751, DOI:http://dx.doi.org/10.14429/dsj.58.170

A prospective observational study of adverse drug reactions to antiretroviral therapy: type and risk factors in a tertiary care teaching hospital

Background: To collect demographic details of patients receiving antiretroviral therapy (ART) and study type of adverse drug reactions (ADRs) and risk factors for ADRs to ART and to assess causality, severity, and preventability assessment of the reported ADRs.Methods: A prospective observational study was conducted for 6 months from January 2012 until June 2012 at ART Center, KR Hospital of Mysore Medical College & Research Institute, Mysore. Data were evaluated for patient demography, risk factors for ADRs, type of ADRs. ADRs were also assessed for their causality, severity, and preventability as per the standard algorithm, using SPSS for windows (version 16.0).Results: Out of 158 patients evaluated, majority were of age group of 21-40 years (66.5%). More number of illiterate patients (55.7%) showed ADRs to ART. Most patients were of CD4 count <250 cells/μl (65.82%). Most common regimen which caused ADRs was zidovudine + lamivudine + nevirapine. Most common type of ADRs was anemia (55.06%) and rash (25.31%). On evaluation of the causality of ADRs, majority were found to be possible (89.24%). The severity assessment showed that most of the patients ADRs were of level 3 (93.05%). The preventability assessment showed that 30.38% patients ADRs were preventable.Conclusion: Identifying risk factors are of crucial importance to optimize the initial choice of ARVs regimen before initiating therapy and to prevent severity and complications caused by ART, thereby improving the quality of care to patients on ART