Megahertz pulse trains enable multi-hit serial femtosecond crystallography experiments at X-ray free electron lasers

The European X-ray Free Electron Laser (XFEL) and Linac Coherent Light Source (LCLS) II are extremely intense sources of X-rays capable of generating Serial Femtosecond Crystallography (SFX) data at megahertz (MHz) repetition rates. Previous work has shown that it is possible to use consecutive X-ray pulses to collect diffraction patterns from individual crystals. Here, we exploit the MHz pulse structure of the European XFEL to obtain two complete datasets from the same lysozyme crystal, first hit and the second hit, before it exits the beam. The two datasets, separated by <1 µs, yield up to 2.1 Å resolution structures. Comparisons between the two structures reveal no indications of radiation damage or significant changes within the active site, consistent with the calculated dose estimates. This demonstrates MHz SFX can be used as a tool for tracking sub-microsecond structural changes in individual single crystals, a technique we refer to as multi-hit SFX

Framing smallholder inclusion in global value chains – case studies from India and West Africa

A resurrected interest in agriculture has brought in its wake growing interest in smallholders in the global South by scholars, companies, governments and development agencies alike. While non-governmental organisations and development agencies see the potential to reduce poverty, companies look upon smallholder agriculture as a widely untapped resource for the sourcing of crops and as a sales market for agricultural inputs. While the important role of large corporate buyers of agricultural produce as lead firms in value chains is often discussed and emphasised, the power of providers of technology and agricultural inputs is being rather neglected. In this paper, we analyse two case studies of technology and input providers in agricultural value chains and their role in smallholder inclusion with the aim of finding out how such companies impact the governance of the value chains. To do so we combine insights from the value chain literature with the concept of framing/overflowing

Anisotropic particles align perpendicular to the flow direction in narrow microchannels

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Broadband Group Velocity Anomaly in Transmission through a Photonic Crystal Slab

We have observed an anomalous group velocity effect for transmission perpendicular to a photonic crystal slab. This is a surprisingly broadband phenomenon, with ΔΩ/Ω \u3e 50%. Our results are consistent with FDTD simulations