Improved Laboratory Transition Probabilities for Neutral Chromium and Re-determination of the Chromium Abundance for the Sun and Three Stars

Branching fraction measurements from Fourier transform spectra in conjunction with published radiative lifetimes are used to determine transition probabilities for 263 lines of neutral chromium. These laboratory values are employed to derive a new photospheric abundance for the Sun: log $\epsilon$(Cr I)$_{\odot}$ = 5.64$\pm$0.01 ($\sigma = 0.07$). These Cr I solar abundances do not exhibit any trends with line strength nor with excitation energy and there were no obvious indications of departures from LTE. In addition, oscillator strengths for singly-ionized chromium recently reported by the FERRUM Project are used to determine: log $\epsilon$(Cr II)$_{\odot}$ = 5.77$\pm$0.03 ($\sigma = 0.13$). Transition probability data are also applied to the spectra of three stars: HD 75732 (metal-rich dwarf), HD 140283 (metal-poor subgiant), and CS 22892-052 (metal-poor giant). In all of the selected stars, Cr I is found to be underabundant with respect to Cr II. The possible causes for this abundance discrepancy and apparent ionization imbalance are discussed.Comment: 44 pages, 6 figure

CHINESE POVERTY: ASSESSING THE IMPACT OF ALTERNATIVE ASSUMPTIONS

This paper investigates how estimates of the extent and trend of consumption poverty in China between 1990 and 2004 vary as a result of alternative plausible assumptions concerning the poverty line and estimated levels of consumption. Our methodology focuses on the following sources of variation: purchasing power exchange rates (used to convert an international poverty line), alternative levels and distributions of private incomes, alternative estimates of the propensity to consume of different income groups, and alternative spatial and temporal price indices. We report national, urban and rural poverty estimates corresponding to distinct assumptions. It is widely believed that substantial poverty reduction took place in China in the 1990s, and we find this conclusion to be largely robust to the choice of assumptions, although estimates of the extent of Chinese poverty, and therefore of world poverty, in any year are greatly influenced by this choice. Copyright 2008 The Authors. Journal compilation 2008 International Association for Research in Income and Wealth Published by Blackwell Publishing.