Tests of model predictions for the responses of stellar spectra and absorption-line indices to element abundance variations. Tests of model predictions for the responses of stellar spectra and absorption-line indices to element abundance variations.

A method that is widely used to analyse stellar populations in galaxies is to apply the theoretically derived responses of stellar spectra and line indices to element abundance variations, which are hereafter referred to as response functions. These are applied in a differential way, to base models, in order to generate spectra or indices with different abundance patterns. In this paper, sets of such response functions for three different stellar evolutionary stages are tested with new empirical [Mg/Fe] abundance data for the medium-resolution Isaac Newton Telescope library of empirical spectra (MILES). Recent theoretical models and observations are used to investigate the effects of [Fe/H], [Mg/H] and overall [Z/H] on spectra, via ratios of spectra for similar stars. The global effects of changes in abundance patterns are investigated empirically through direct comparisons of similar stars from MILES, highlighting the impact of abundance effects in the blue part of the spectrum, particularly for lower temperature stars. It is found that the relative behaviour of iron-sensitive line indices are generally well predicted by response functions, whereas Balmer line indices are not. Other indices tend to show large scatter about the predicted mean relations. Implications for element abundance and age studies in stellar populations are discussed and ways forward are suggested to improve the match with the behaviour of spectra and line-strength indices observed in real stars

The Persistence of (Subnational) Fortune

Abstract Using subnational historical data, this paper establishes the within country persistence of economic activity in the New World over the last half millennium, a period including the trauma of the European colonization, the decimation of the native populations, and the imposition of potentially growth inhibiting institutions. We construct a data set incorporating measures of pre-colonial population density, new measures of present regional per capita income and population, and a comprehensive set of locational fundamentals. These fundamentals are shown to have explanatory power: native populations throughout the hemisphere were found in more livable and productive places. We then show that high pre-colonial density areas tend to be dense today: population agglomerations persist. The data and historical evidence suggest this is due partly to locational fundamentals, but also to classic agglomeration effects: colonialists established settlements near existing native populations for reasons of labor, trade, knowledge and defense. The paper then shows that high density (historically prosperous) areas also tend to have higher incomes today, and largely due to agglomeration effects: fortune persists for the United States and most of Latin America. JEL: J1, N9, R1, O1, O4

We would like to thank the NBER for support via the Africa Project. We would like to thank Bill

The views expressed in the HKS Faculty Research Working Paper Series are those of the author(s) and do not necessarily reflect those of the John F. Kennedy School of Government or of Harvard University. Faculty Research Working Papers have not undergone formal review and approval. Such papers are included in this series to elicit feedback and to encourage debate on important public policy challenges. Copyright belongs to the author(s). Papers may be downloaded for personal use only. www.hks.harvard.edu NBER WORKING PAPER SERIE