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The rhopalia and statocysts of Periphylla periphylla (Péron and Lesueur in Ann Mus Hist Nat Marseille 14:316-366,) and Chironex fleckeri Southcott (Aust J Mar Freshw Res 7(2):254-280 ) were examined histologically and showed several homologous characteristics. Differences in sensory area distribution could be connected to a slightly different functionality of equilibrium sensing. In P. periphylla, the statoliths (crystals) grow independently of each other; whereas in C. fleckeri, one large crystal covers the smaller ones. The structures of both statoliths were examined in detail with single-crystal diffraction, microtomography and diffraction contrast tomography. The single compact statolith of C. fleckeri consisted of bassanite as was previously known only for other rhopaliophoran medusae. An origin area with several small oligocrystals was located in the centre of the cubozoan statolith. The origin areas and the accretion of statoliths are similar in both species. Our results lead to the assumption that the single bassanite statolith of C. fleckeri (Cnidaria, Cubozoa) is a progression of the scyphozoan multiplex statolith. It is therefore suggested that the Cubozoa are derived from a scyphozoan ancestor and are a highly developed taxa within the Rhopaliophora. [ABSTRACT FROM AUTHOR]

The globally distributed coronate scyphomedusa Periphylla periphylla (Peron and Lesueur, 1809) occurs in permanent and extremely high abundance in some Norwegian fjords. Studies on the species in Lurefjorden, 40 km north of Bergen, have revealed a holopelagic life cycle with direct development. We distinguished 14 successive developmental stages, characterised by size and morphology. Eggs and early stages are non-mobile, neutrally buoyant, and found mainly at intermediate depths. Rearing studies indicated a development time of 2-3 months from fertilisation to stage 9, when the medusa starts feeding and becomes motile. The fjord population usually shows a strong diel vertical migration, with aggregations at shallower depths during the night. The development includes a gradual increase in pigmentation (porphyrins), starting with the stomach, and thereafter extending to tentacles and the whole exumbrella. This pigment is photodegraded by natural light. Rearing experiments in the laboratory have shown a lethal effect of light. Here, development stops at stage 5. Pigments become visible in stage 7. Older medusae are severely damaged and killed within a few days by exposure to daylight. All stages of P. periphylla are bioluminescent, with this capacity increasing with growth, probably in connection with the development of the nervous net. The light reaction starts at the point of stimulation and spreads at two different speeds corresponding to the two nerve nets of the medusae. The coronal furrow has a central function in transmission of the reaction. It is hypothesised that the bioluminescence is used mainly as a warning to some potential predators, signalling that the porphyrin-containing medusa is unpalatable. P. periphylla has the same two categories of nematocysts as other coronates, with a total of six different types. Nematocyst abundance, distribution and morphology indicate their function. The giant euryteles (capsule up to 100 µm and tubule up to 1160... [ABSTRACT FROM AUTHOR]

The flavor of boiled potatoes was investigated using sensory and instrumental methods to get basic information concerning sensory features and aroma compounds for use in breeding research and quality control. The sensory odor profiles of three genotypes were found to differ especially in negative sensations like “burnt”, “fodder” and “musty”. The aroma volatiles were isolated by a modified simultaneous steam distillation and extraction method. Nineteen character impact compounds of boiled potato aroma were pointed out by gas chromatography with nitrogen specific detection, gas chromatography —mass spectrometry and gas chromatography —olfactometry. The comparison of the quantified odor impressions in three genotypes by chromatography —olfactometry revealed the substances responsible for the typical boiled potato odorants and off-flavor notes. [ABSTRACT FROM AUTHOR]

Si- and Mg-ions with energies of 180 keV have been implanted into semi-insulating InP substrates and low doped n- and p-type GalnAs epitaxial layers (3 · l0cm). Sheet resistances and doping profiles are analyzed and compared with LSS theory. Post-implantation annealing is studied with respect to encapsulation, time and temperature. We have tested as new encapsulation techniques for InP the simple proximity cap annealing and for GalnAs the As-doped spun-on SiO. Proximity cap annealing yields decomposition-free surfaces when using a recessed capsubstrate. At annealing temperatures of around 800 °C less activation is obtained than with conventional PSG annealing and a surface accumulation of charge-carriers is established. A time limit of around 3 min is found for Si- and Mg-implanted InP, beyond which the sheet resistance no longer decreases and the doping saturates. For Si in InP, short-time annealing yields to a 68 % activation of carriers, not significantly higher than with conventional long-time annealing. In the case of Si in GalnAs, however, short-time annealing is much more effective. A 100 % activation is obtained for a dose of 2.10 cm, while only 7 % is found for long annealing. Even at such a high dose of 1. 10cm we have achieved about an order of magnitude higher activation with short annealing than with long annealing. [ABSTRACT FROM AUTHOR]

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