The language of crisis: spatiotemporal effects of COVID-19 pandemic dynamics on health crisis communications by political leaders.

In times of crisis, communication by leaders is essential for mobilizing an effective public response. During the COVID-19 pandemic, compliance with public health guidelines has been critical for the prevention of infections and deaths. We assembled a corpus of over 1500 pandemic-related speeches, containing over 4 million words, delivered by all 50 US state governors during the initial months of the COVID-19 pandemic.

Self-Seeded Axio-Radial InAs-InAsP Nanowire Heterostructures beyond "Common" VLS Growth.

Semiconductors are essential for modern electronic and optoelectronic devices. To further advance the functionality of such devices, the ability to fabricate increasingly complex semiconductor nanostructures is of utmost importance. Nanowires offer excellent opportunities for new device concepts; heterostructures have been grown in either the radial or axial direction of the core nanowire but never along both directions at the same time.

Surface morphology of Au-free grown nanowires after native oxide removal.

Using scanning tunneling microscopy, we evaluate the surface structure and morphology down to the atomic scale for micrometers along Au-free grown InAs nanowires (NWs) free from native oxide. We find that removal of the native oxide (which covers the NWs upon exposure to the ambient air) using atomic hydrogen does not alter the underlying step structure. Imaging with sub-nanometer resolution along the NWs, we find an extremely low tapering (diameter change along the NW) of 1.

X-ray diffraction strain analysis of a single axial InAs 1-x Px nanowire segment.

The spatial strain distribution in and around a single axial InAs 1-x Px hetero-segment in an InAs nanowire was analyzed using nano-focused X-ray diffraction. In connection with finite-element-method simulations a detailed quantitative picture of the nanowire's inhomogeneous strain state was achieved. This allows for a detailed understanding of how the variation of the nanowire's and hetero-segment's dimensions affect the strain in its core region and in the region close to the nanowire's side facets.