Virtualization has been deployed as a key enabling technology for coping with the ever growing complexity and heterogeneity of modern computing systems. However, on its own, classical virtualization is a poor match for modern endpoint embedded system requirements such as safety, security and real-time, which are our main target. Microkernel-based approaches to virtualization have been shown to bridge the gap between traditional and embedded virtualization. This notwithstanding, existent microkernel-based solutions follow a highly para-virtualized approach, which inherently requires a significant software engineering effort to adapt guest operating systems (OSes) to run as userland components. In this paper, we present µRTZVisor as a new TrustZone-assisted hypervisor that distinguishes itself from state-of-the-art TrustZone solutions by implementing a microkernel-like architecture while following an object-oriented approach. Contrarily to existing microkernel-based solutions, µRTZVisor is able to run nearly unmodified guest OSes, while, contrarily to existing TrustZone-assisted solutions, it provides a high degree of functionality and configurability, placing strong emphasis on the real-time support. Our hypervisor was deployed and evaluated on a Xilinx Zynq-based platform. Experiments demonstrate that the hypervisor presents a small trusted computing base size (approximately 60KB), and a performance overhead of less than 2% for a 10 ms guest-switching rate.

Launched in August 2018, NASA's Parker Solar Probe mission has now completed 8 of its 24 scheduled encounters with the Sun and has flown as close as 15 solar radii from its surface. The mission probes the processes behind coronal heating, the acceleration of the solar wind, and the energization of solar energetic particles. Its data have revealed new phenomena, some of which were quite unexpected.This special issue presents nearly 40 articles, reporting new discoveries and progress on previous findings as well as describing data analysis, theory, and modeling. Major topics include magnetic switchbacks, waves and their roles in heating the solar plasma, the solar angular momentum, and the diversity of small energetic particle events. Dust dynamics is also becoming an important topic as more data are accumulated from the innermost heliosphere. Turbulence in the solar wind, which has long been a leading candidate for energizing the solar plasma, may play an even more prominent role than previously thought.Parker Solar Probe is continuing its journey and will start making its closest approaches to our star by December 2024. At the same time, the Sun will pass from the solar minimum conditions sampled so far, and the rising solar cycle will no doubt provide new Parker Solar Probe discoveries in regions of increasingly complex solar wind and solar activity.

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On the island nation of São Tomé and Príncipe, West Africa, only one species of terrapin has been recorded: the West African mud turtle, Pelusios castaneus. Here, we use a mtDNA phylogenetic approach to shed light on the geographical origin of Pelusios castaneus on both islands. Our results indicate several independent colonisations from different African mainland regions (Nigeria, Ivory Coast, Sierra Leone and Congo). However, it is still unclear if the species arrived on the islands by natural dispersal (e.g., through vegetation rafts) or by human agency (e.g., as a food source). Our work provides important insights into the origins of P. castaneus in São Tomé and Príncipe, but a more in-depth study is needed to fully understand the origins and evolutionary histories of these populations.