Access to health infrastracture and child health development: Evidence from post-apartheid South Africa

A growing body of literature shows that child health has substantial long-term economic impacts. This study examines whether, and to what extent, increased access to health infrastructure leads to better child health status as measured by weight-for-age z-scores. To assess the causal relationship, I exploit plausibly exogenous variation in access induced by the dramatic change in health policy in South Africa immediately after the end of apartheid. Using longitudinal household data, health services are found to improve the nutritional status of not only newly born babies but also children who were already born at low health status. Yet, the effects are significant only for boys.The 12th ISER-Moriguchi Prize (2009) Awarded Paper

Precipitation of amorphous ferromagnetic semiconductor phase in epitaxially grown Mn-doped Ge thin films

We investigated the origin of ferromagnetism in epitaxially grown Mn-doped Ge thin films. Using low-temperature molecular beam epitaxy, Mn-doped Ge films were successfully grown without precipitation of ferromagnetic Ge-Mn intermetallic compounds, such as Mn5Ge3. Magnetic circular dichroism measurements revealed that the epitaxially grown Mn-doped Ge films exhibited clear ferromagnetic behavior, but the Zeeman splitting observed at the critical points was not induced by the s,p-d exchange interactions. High-resolution transmission electron microscopy and energy dispersive X-ray spectroscopy analyses show phase separation of amorphous Ge1-xMnx clusters with high Mn content from a Mn-free monocrystalline Ge matrix. Since amorphous Ge1-xMnx was characterized as a homogeneous ferromagnetic semiconductor, the precipitation of the amorphous Ge1-xMnx clusters is the origin of the ferromagnetic semiconductor behavior of the epitaxially grown Mn-doped Ge films.Comment: 12pages, 4figure