Christian Holzner

Learn More
Scanning X-ray microprobes are unique tools for the nanoscale investigation of specimens from the life, environmental, materials and other fields of sciences. Typically they utilize absorption and fluorescence as contrast mechanisms. Phase contrast is a complementary technique that can provide strong contrast with reduced radiation dose for weakly absorbing(More)
Scanning X-ray fluorescence microscopy (XFM) is a particularly useful method for studying the spatial distribution of trace metals in biological samples. Here we demonstrate the utility of combining coherent diffractive imaging (CDI) with XFM for imaging biological samples to simultaneously produce high-resolution and high-contrast transmission images and(More)
Scanning X-ray microscopy focuses radiation to a small spot and probes the sample by raster scanning. It allows information to be obtained from secondary signals such as X-ray fluorescence, which yields an elemental mapping of the sample not available in full-field imaging. The analysis and interpretation from these secondary signals can be considerably(More)
We developed a technique for performing quantitative phase reconstructions from differential phase contrast images obtained using a configured detector in a scanning transmission X-ray microscope geometry. The technique uses geometric optics to describe the interaction of the X-ray beam with the specimen, which allows interpretation of the measured(More)
X-ray fluorescence tomography promises to map elemental distributions in unstained and unfixed biological specimens in three dimensions at high resolution and sensitivity, offering unparalleled insight in medical, biological, and environmental sciences. X-ray fluorescence tomography of biological specimens has been viewed as impractical-and perhaps even(More)
Micro computed tomography (micro-CT) is a widely-used imaging technique. A challenge of micro-CT is to quantitatively reconstruct a sample larger than the field-of-view (FOV) of the detector. This scenario is characterized by truncated projections and associated image artifacts. However, for such truncated scans, a low resolution scout scan with an(More)
We introduce skill groups and different production technologies with constant or increasing returns to scale into the Burdett-Mortensen model of on-the-job search. Supermodularity of the different skill groups in the production process leads to a positive intrafirm wage correlation between skill groups. Increasing returns to scale allows the theoretical(More)
We study the effect of childcare costs on the fertility behavior of Swedish women and find that reductions in childcare charges influence fertility decisions, even when costs are initially highly subsidized. Exploiting the exogenous variation in childcare costs caused by a Swedish childcare reform in 2002, we are able to identify the causal effect of(More)