Human capital, culture and the onset of the demographic transition

This paper uses estimates of the dates at which different countries have experienced their demographic transitions to examine the main historical determinants of these transitions. We first show that genetic distance to the United Kingdom, a measure of cultural relatedness used in Spolaore and Wacziarg (2009), is positively associated with the onset of the demographic transition, implying that countries that have a larger genetic distance from the UK tend to experience later transitions. We then unveil a plausible mechanism that can rationalize this result. We show that genetic distance to the UK is negatively related to a country's initial human capital, measured as its schooling level in 1870. One interpretation of this finding is that a larger genetic distance is associated with higher barriers to technological diffusion and hence a lower demand for human capital. This low demand for human capital then delays the demographic transition by providing less incentives for households to switch from quantity to quality of children. Instrumenting initial human capital using genetic distance to the UK and alternative measures of adherence to Protestantism, we confirm the causal link between human capital and the onset of the demographic transition. Further, we show that the impact of cultural relatedness to the UK can be mainly attributed to its effect on educational levels

Fertility and financial development: evidence from U.S. counties in the 19th century

This paper uses data on fertility and financial development in 19th century U.S. to test the hypothesis that more developed local financial markets reduce the incentives for families to have a large offspring to provide for them at old age, the so-called old-age security hypothesis. We find that the presence of banks is associated to lower children-to-women ratios and crude birth rates even after controlling for a large set of socio-economic factors. To account for possible endogeneity of bank location we instrument for the presence of some banking activity in a given county in 1840 with the existence of at least a bank in that county in 1820. The results of using this identification strategy are in line with the OLS ones, namely that fertility in 1850 is negatively affected by financial development. Next we explore the relationship between banking activity and fertility in the state of Pennsylvania, where, by law, most banks were created before 1820. This allows us to treat banks in 1840 as exogenous and confirm the existence of a strong negative causal effect from financial development to fertility. Finally, we show that our results are robust to measuring banking activity with the number of cities with at least a bank in a given county

Household location and income: a spatial analysis for British cities

Using information on the exact location of urban households in Britain for the period 2009-2013 we explore the validity of standard urban land use models by estimating the extent to which distance of residence from the city centre is a function of income. This is the first study of its kind for British cities. After controlling for household characteristics and access to transport, as well as city and time effects, and taking account of both spatial and serial correlation, we find a strong positive association between household’s income and distance from the city centre. We also estimate the income elasticity of demand for land and find that this is not large enough to support the view that richer households locate further from the city centre mainly because they prefer larger dwellings. Finally, we find that while poorer households live closer to the city centre, they have experienced increasing real incomes over the period relative to those who live further away. This supports the view that cities in Britain attract poor people rather than generate poverty

Household location in English cities

This paper is the first to test an amenity-based sorting model for cities in England. We explore household location under both monocentric and polycentric assumptions about city structure. On average, we find no systematic relationship between income and household distance to the city centre. However, there are differences between cities, with a positive income-distance relationship in Birmingham and Leeds, and a negative relationship in Newcastle. Household heterogeneity is also important; for example, on average households with heads who are migrants live 25% closer to the centre than non-migrants. We also find that only the employed (and those above the poverty line) are influenced by the availability of public transport, which is in direct opposition to the US evidence

A theoretical analysis of Ballistic Electron Emission Microscopy: k-space distributions and spectroscopy

We analyze BEEM experiments. At low temperatures and low voltages, near the threshold value of the Schottky barrier, the BEEM current is dominated by the elastic component. Elastic scattering by the lattice results in the formation of focused beams and narrow lines in real space. To obtain the current injected in the semiconductor, we compute the current distribution in reciprocal space and, assuming energy and $k_{\parallel}$ conservation. Our results show an important focalization of the injected electron beam and explain the similarity between BEEM currents for Au/Si(111) and Au/Si(100).Comment: 17 pages, 5 figures (postscript), Latex, APS, http://www.icmm.csic.es/Pandres/pedro.htm. Appl. Surf. Sci. (in press

Nanoscale Visualization of Elastic Inhomogeneities at TiN Coatings Using Ultrasonic Force Microscopy

Ultrasonic force microscopy has been applied to the characterization of titanium nitride coatings deposited by physical vapor deposition dc magnetron sputtering on stainless steel substrates. The titanium nitride layers exhibit a rich variety of elastic contrast in the ultrasonic force microscopy images. Nanoscale inhomogeneities in stiffness on the titanium nitride films have been attributed to softer substoichiometric titanium nitride species and/or trapped subsurface gas. The results show that increasing the sputtering power at the Ti cathode increases the elastic homogeneity of the titanium nitride layers on the nanometer scale. Ultrasonic force microscopy elastic mapping on titanium nitride layers demonstrates the capability of the technique to provide information of high value for the engineering of improved coatings

Is it possible to detect planets around young active G and K dwarfs?

Theoretical predictions suggest that the distribution of planets in very young stars could be very different to that typically observed in Gyr old systems that are the current focus of radial velocity surveys. However, the detection of planets around young stars is hampered by the increased stellar activity associated with young stars, the signatures of which can bias the detection of planets. In this paper, we place realistic limitations on the possibilities for detecting planets around young active G and K dwarfs. The models of stellar activity based on tomographic imaging of the G dwarf HD 141943 and the K1 dwarf AB Dor also include contributions from plage and many small random starspots. Our results show that the increased stellar activity levels present on young solar-type stars strongly impacts the detection of Earth-mass and Jupiter-mass planets and that the degree of activity jitter is directly correlated with stellar v sin i. We also show that for G and K dwarfs, the distribution of activity in individual stars is more important than the differences in induced radial velocities as a function of spectral type. We conclude that Jupiter-mass planets can be detected close-in around fast-rotating young active stars, Neptune-mass planets around moderate rotators and that Super-Earths are only detectable around very slowly rotating stars. The effects of an increase in stellar activity jitter by observing younger stars can be compensated for by extending the observational base-line to at least 100 epochs.Peer reviewe

Interaction imaging with amplitude-dependence force spectroscopy

Knowledge of surface forces is the key to understanding a large number of processes in fields ranging from physics to material science and biology. The most common method to study surfaces is dynamic atomic force microscopy (AFM). Dynamic AFM has been enormously successful in imaging surface topography, even to atomic resolution, but the force between the AFM tip and the surface remains unknown during imaging. Here, we present a new approach that combines high accuracy force measurements and high resolution scanning. The method, called amplitude-dependence force spectroscopy (ADFS) is based on the amplitude-dependence of the cantilever's response near resonance and allows for separate determination of both conservative and dissipative tip-surface interactions. We use ADFS to quantitatively study and map the nano-mechanical interaction between the AFM tip and heterogeneous polymer surfaces. ADFS is compatible with commercial atomic force microscopes and we anticipate its wide-spread use in taking AFM toward quantitative microscopy

Fueling the gender gap? Oil and women's labor and marriage market outcomes

This paper analyzes the effect of resource-based economic specialization on women's labor market outcomes. Using information on the location and discovery of major oil fields in the Southern United States coupled with a county-level panel derived from US Census data for 1900-1940, we specifically test the hypothesis that the presence of mineral resources can induce changes in the sectoral composition of the local economy that are detrimental to women's labor market outcomes. We find evidence that the discovery of oil at the county level may constitute a substantial male biased demand shock to local labor markets, as it is associated with a higher gender pay gap. However, we find no evidence that oil wealth lowers female labor force participation or has any impact on local marriage and fertility patterns. While our results are consistent with oil shocks limiting female labor market opportunities in some sectors (mainly manufacturing), this effect tends to be compensated by the higher availability of service sector jobs for women who are therefore not driven out of the labor market