A high current hollow cathode source has been developed as a radiometric source standard for the extreme VUV. The source is operated at a constant current of 2 A with an aluminum cathode and helium or argon as buffer gas at pressures of -1 hPa. The radiance of spectral lines in the wavelength range from 13 to 60 nm has been determined by comparison to the calculable spectral radiant power of the electron storage ring BESSY.An uncertainty of the order of 13% has been achieved for most of the investigated lines. The spectral emission is stable to better than 5% for an operating time of 30 h. An exchange of the cathode restores the original radiance.

This confidence coding is overlaid within a more pronounced pupil dilation that reflects post-decision components that are related to the response itself but not to the decision. We also provide evidence as to how different behavioral states, imposed by task demands, modulate what the pupil is reflecting, presumably showing what the underlying cognitive network is coding for.

The sandfish lizard, Scincus scincus (Squamata: Scincidae), spends nearly its whole life in aeolian sand and only comes to the surface for foraging, defecating and mating. It is not yet understood how the animal can respire without sand particles entering its respiratory organs when buried under thick layers of sand. In this work, we integrated biological studies, computational calculations and physical experiments to understand this phenomenon. We present a 3D model of the upper respiratory system based on a detailed histological analysis. A 3D-printed version of this model was used in combination with characteristic ventilation patterns for computational calculations and fluid mechanics experiments. By calculating the velocity field, we identified a sharp decrease in velocity in the anterior part of the nasal cavity where mucus and cilia are present. The experiments with the 3D-printed model validate the calculations: particles, if present, were found only in the same area as suggested by the calculations. We postulate that the sandfish has an aerodynamic filtering system; more specifically, that the characteristic morphology of the respiratory channel coupled with specific ventilation patterns prevent particles from entering the lungs.

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