Operational scales, sources of finance, and firms’ performance: evidence from Vietnamese longitudinal data

This study investigates a longitudinal dataset consisting of financial and operational data from 37 listed companies listed on Vietnamese stock market, covering the period 2004-13. By performing three main types of regression analysis - pooled OLS, fixed-effect and random-effect regressions - the investigation finds mixed results on the relationships between operational scales, sources of finance and firms' performance, depending on the choice of analytical model and use of independent/dependent variables. In most situation, fixed-effect models appear to be preferable, providing for reasonably consistent results. Toward the end, the paper offers some further explanation about the obtained insights, which reflect the nature of a business environment of a transition economy and an emerging market.

What the awkward relatives tell us about planetary nebulae hosting binary systems

Relatives to Planetary Nebulae, such as barium stars or symbiotic systems, can shed light on the connection between Planetary Nebulae and binarity. Because of the observational selection effects against direct spectroscopic detection of binary PNe cores with orbital periods longer than a few dozen days, at present these "awkward relatives" are a critical source of our knowledge about the binary PNe population at longer periods. Below a few examples are discussed, posing constraints on the attempts to model nebula, ejection process in a binary. © 2006 International Astronomical Union.