Study of X-ray emission from the old open cluster, M67

We present an X-ray analysis of a 4 Gyr old open cluster, M67, using archival XMM-Newton data. The aim of this study was to find new X-ray members of M67, and to use the updated member list for studying X-ray variability, and derive the X-ray luminosity functions (XLFs) of different stellar types and compare them with other star clusters of similar age. We report the detection of X-ray emission from 25 members of M67, with membership based primarily on their proper motion, of which one X-ray source is a new member. Supplementing this study with previous ROSAT and Chandra studies of M67, and using the most recent proper motion study by Vereshchagin et al., we have compiled a revised list of X-ray emitting members of M67 consisting of 43 stars. Sixteen of these are known RS CVn type binaries having orbital periods $<$ 10 days, and near-circular orbits, 5 are contact binaries with orbital periods $<$ 6 hours, 5 are yellow and blue stragglers, 2 are Algol-type binaries, and one source is a cataclysmic variable. Fourteen members do not have any orbital information and cannot be classified. Fourteen of the X-ray sources detected do not have any optical counterpart down to a magnitude of $V\simeq22$, and their membership is uncertain. Finally, we report the X-ray luminosity functions of RS CVn type and other types of stars in M67 and compare them with other open clusters of intermediate-to-old age.Comment: 13 pages, 8 figures, 5 tables. Accepted for publication in MNRA

Knowledge and Attitudes on Fetal Anomalies Among Pregnant Women in Teaching Hospital Mahamodara, Galle

Fetal anomalies significantly contribute towards neonatal mortality worldwide. In Sri Lanka major cause for neonatal deaths is fetal anomalies 41%. A Descriptive cross-sectional study was conducted in Antenatal clinic, Teaching Hospital, Mahamodara. An interviewer-administered, pretested questionnaire was used. Hundred and fifty pregnant women participated in this study. Majority; 105 (70%) were found in the age of below 30 years, and 80 (53.3%) educated up to G.C.E. Ordinary Level. 83 (53.3%) were multigravida and 93(62%) were planned pregnancies. Higher proportion of the participants; 92(61%) , 88(56.7%) and 123(82%) had good knowledge on the risk factors, pre conception care and on preventive actions related to birth defects respectively. Significant proportion (26.7%) had poor knowledge regarding birth defects. There are 143 (95.3%) of the participants interested to know more information on birth defects, 72% believed birth defects were due to evil spirits. Even though 52% of women did not want to terminate their pregnancy if they had a fetus with anomalies, 80.7% of them opined that the termination of pregnancy with birth defected should be legalized. The educational level, parity and planning of current pregnancy of the participants were significantly correlated (p &lt; 0.05) with their knowledge on pre conception care, preventive actions, knowledge on risk factors on birth defects

Multiplicity fluctuations in heavy-ion collisions using canonical and grand-canonical ensemble

We report the higher order cumulants and their ratios for baryon, charge and strangeness multiplicity in canonical and grand-canonical ensembles in ideal thermal model including all the resonances. When the number of conserved quanta is small, an explicit treatment of these conserved charges is required, which leads to a canonical description of the system and the fluctuations are significantly different from the grand canonical ensemble. Cumulant ratios of total charge and net-charge multiplicity as a function of collision energies are also compared in grand canonical ensemble.Comment: 7 pages, 5 Figs, Published versio

Linear and nonlinear properties of Rao-dust-Alfv\'en waves in magnetized plasmas

The linear and nonlinear properties of the Rao-dust-magnetohydrodynamic (R-D-MHD) waves in a dusty magnetoplasma are studied. By employing the inertialess electron equation of motion, inertial ion equation of motion, Amp\`ere's law, Faraday's law, and the continuity equation in a plasma with immobile charged dust grains, the linear and nonlinear propagation of two-dimensional R-D-MHD waves are investigated. In the linear regime, the existence of immobile dust grains produces the Rao cutoff frequency, which is proportional to the dust charge density and the ion gyrofrequency. On the other hand, the dynamics of an amplitude modulated R-D-MHD waves is governed by the cubic nonlinear Schroedinger equation. The latter has been derived by using the reductive perturbation technique and the two-timescale analysis which accounts for the harmonic generation nonlinearity in plasmas. The stability of the modulated wave envelope against non-resonant perturbations is studied. Finally, the possibility of localized envelope excitations is discussed.Comment: 30 pages, 8 figures, to appear in Physics of Plasma