Explore the vast range of titles available.

Deciphering the physical properties of flares is crucial for understanding the nature of one of the most energetic events on the Sun. We analyze high spatial and spectral resolution observations of a C-class flare, focusing on a complex light bridge in the active region. The observations show Stokes profiles with opposite Doppler shifts and asymmetries between photospheric and chromospheric spectral lines, and Ca ii infrared spectral lines in emission, tracing areas of extreme atmospheric heating. Inversion results are consistent with these spectral features, showing regions of opposite-sign plasma flows between the photosphere and chromosphere, adjacent to areas with extreme chromospheric temperatures. The latter areas show relatively weak line-of-sight velocities despite the intense heating. The magnetic field configuration shows abrupt changes with height in the regions with opposite-sign flows, while remaining nearly constant with height in the areas of extreme heating. These findings point to a scenario of small-scale magnetic reconnection in the photosphere, suggesting a flare triggering mechanism based on an avalanche of many small reconnection events.

The third science flight of the balloon-borne solar observatory Sunrise carries three entirely new post-focus science instruments with spectropolarimetric capabilities, concurrently covering an extended spectral range from the near ultraviolet to the near infrared. Sampling a larger height range, from the low photosphere to the chromosphere, with the sub-arcsecond resolution provided by the 1-m Sunrise telescope, is key in understanding critical small-scale phenomena which energetically couple different layers of the solar atmosphere. The Sunrise Ultraviolet Spectropolarimeter and Imager (SUSI) operates between 309 nm and 417 nm. A key feature of SUSI is its capability to record up to several hundred spectral lines simultaneously without the harmful effects of the Earth's atmosphere. The rich SUSI spectra can be exploited in terms of many-line inversions. Another important innovation of the instrument is the synchronized 2D context imaging which allows to numerically correct the spectrograph scans for residual optical aberrations. In this work we describe the main design aspects of SUSI, the instrument characterization and testing, and finally its operation, expected performance and data products.

Enteroaggregative E. coli (EAEC) are a major cause of diarrhoea worldwide. Due to their heterogeneity and carriage in healthy individuals, identification of diagnostic virulence markers for pathogenic strains has been difficult. In this study, we have determined phenotypic and genotypic differences between EAEC strains of sequence types (STs) epidemiologically associated with asymptomatic carriage (ST31) and diarrhoeal disease (ST40). ST40 strains demonstrated significantly enhanced intestinal adherence, biofilm formation, and pro-inflammatory interleukin-8 secretion compared with ST31 isolates. This was independent of whether strains were derived from diarrhoea patients or healthy controls. Whole genome sequencing revealed differences in putative virulence genes encoding aggregative adherence fimbriae, E. coli common pilus, flagellin and EAEC heat-stable enterotoxin 1. Our results indicate that ST40 strains have a higher intrinsic potential of human pathogenesis due to a specific combination of virulence-related factors which promote host cell colonization and inflammation. These findings may contribute to the development of genotypic and/or phenotypic markers for EAEC strains of high virulence.