Introduction: Students in elementary schools due to the physical and behavioral characteristics more than adults have exposed to environmental hazards. This study was conducted to examine the environmental health and safety indices in girls' elementary schools in Ilam city. Materials and methods: This cross-sectional study was carried out via census sampling method in girls' elementary schools...

Context. The evolution of magnetic fields in Ap stars during the main sequence phase is presently mostly unconstrained by observation because of the difficulty of assigning accurate ages to known field Ap stars. Aims. We are carrying out a large survey of magnetic fields in cluster Ap stars with the goal of obtaining a sample of these stars with well-determined ages. In this paper we analyse th...

We have carried out K-band speckle observations of a sample of 114 X-ray selected weak-line T Tauri stars in the nearby Scorpius-Centaurus OB association. We find that for binary T Tauri stars closely associated to the early type stars in Upper Scorpius, the youngest subgroup of the OB association, the peak in the distribution of binary separations is at 90 A.U. For binary T Tauri stars located...

Nineteen carbon stars that show lithium enrichment in their atmospheres have been discovered among a sample of 674 carbon stars in the Large Magellanic Cloud. Six of the Li-rich carbon stars are of J-type, i.e., with strong C isotopic features. No superLi-rich carbon stars were found. The incidence of lithium enrichment among carbon stars in the LMC is much rarer than in the Galaxy, and about f...

We present the results of a study of a large sample of A and Am stars with spectral types from LAMOST and light curves from WASP. We find that, unlike normal A stars, δ Sct pulsations in Am stars are mostly confined to the effective temperature range 6900 < Teff < 7600K. We find evidence that the incidence of pulsations in Am stars decreases with increasing metallicism (degree of chemical pecul...

ASTRONOMY AND ASTROPHYSICS The birth of strange stars and their dynamo-originated magnetic fields Abstract. It is shown that protostrange stars (PSSs) can be convective and that there are two possible scenarios describing their turbulence. Besides the local turbulence on the scale which is less than the mean free path of neu-trinos, large-scale (∼ 1 km) convection also may occur with properties...

We present Be star candidates in the open cluster NGC663, identified by Hα imaging photometry with the Palomar Transient Factory Survey, as a pilot program to investigate how the Be star phenomena, the emission spectra, extended circumstellar envelopes, and fast rotation, correlate with massive stellar evolution. Stellar membership of the candidates was verified by 2MASS magnitudes and colors, ...

Contact binary stars are common variable stars which are all believed to emit relatively large fluxes of x-rays. In this work we combine a large new sample of contact binary stars derived from the ROTSE-I telescope with x-ray data from the ROSAT All-Sky Survey (RASS) to estimate the x-ray volume emissivity of contact binary stars in the galaxy. We obtained x-ray fluxes for 140 contact binaries ...

The luminosities, effective temperatures and metallicities that are derived empirically by Kovács and Jurcsik from the light curves of a large number of globular cluster and field RRab and RRc stars are compared to theoretical RR Lyrae models. The strong luminosity dependence of the empirical blue and red edges (LogL vs. LogTeff diagram) is in disagreement with that of both radiative and convec...