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Abstract: The deep sea is an extremely diverse habitat, which is now threatened by human activity. Means for evaluating the response of deep-sea creatures to environmental perturbation are limited because of lethal decompression effects during sampling. The addressing of this issue requires that target species be (i) captured at depth, (ii) recovered at natural pressure, (iii) submitted to in vivo investigations. Although a single container may meet these requirements, we believe that using several dedicated cells greatly expands experimental possibilities. Accordingly, we have designed a new sampling system which has been named PERISCOP and which has accounted for the selective capture and recovery of live animals from depths exceeding 2000m. Three hydrothermal vent shrimp species were sampled on the Mid-Atlantic Ridge, from depths of 1700 and 2300m. In addition, a fish caught at 2300m depth reached the surface in very good condition. This is by far the deepest record for the pressurized recovery of a live deep-sea fish. Our prototype aims at making pressurized recovery a more efficient and practical process. Finally, future evolutions of sampling methods are discussed based on the present design of the PERISCOP. [Copyright &y& Elsevier]

Zirconium pentatelluride was recently reported to be a 3D Dirac semimetal, with a single conical band, located at the center of the Brillouin zone. The cone's lack of protection by the lattice symmetry immediately sparked vast discussions about the size and topological or trivial nature of a possible gap opening. Here, we report on a combined optical and transport study of ZrTe5, which reveals an alternative view of electronic bands in this material. We conclude that the dispersion is approximately linear only in the a-c plane, while remaining relatively flat and parabolic in the third direction (along the b axis). Therefore, the electronic states in ZrTe5 cannot be described using the model of 3D Dirac massless electrons, even when staying at energies well above the band gap 2Δ=6 meV found in our experiments at low temperatures. [ABSTRACT FROM AUTHOR]