64 research outputs found

    Ridge Formation and De-Spinning of Iapetus via an Impact-Generated Satellite

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    We present a scenario for building the equatorial ridge and de-spinning Iapetus through an impact-generated disk and satellite. This impact puts debris into orbit, forming a ring inside the Roche limit and a satellite outside. This satellite rapidly pushes the ring material down to the surface of Iapetus, and then itself tidally evolves outward, thereby helping to de-spin Iapetus. This scenario can de-spin Iapetus an order of magnitude faster than when tides due to Saturn act alone, almost independently of its interior geophysical evolution. Eventually, the satellite is stripped from its orbit by Saturn. The range of satellite and impactor masses required is compatible with the estimated impact history of Iapetus.Comment: 19 pages, 3 figures; Icarus, in pres

    Tidal friction in close-in satellites and exoplanets. The Darwin theory re-visited

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    This report is a review of Darwin's classical theory of bodily tides in which we present the analytical expressions for the orbital and rotational evolution of the bodies and for the energy dissipation rates due to their tidal interaction. General formulas are given which do not depend on any assumption linking the tidal lags to the frequencies of the corresponding tidal waves (except that equal frequency harmonics are assumed to span equal lags). Emphasis is given to the cases of companions having reached one of the two possible final states: (1) the super-synchronous stationary rotation resulting from the vanishing of the average tidal torque; (2) the capture into a 1:1 spin-orbit resonance (true synchronization). In these cases, the energy dissipation is controlled by the tidal harmonic with period equal to the orbital period (instead of the semi-diurnal tide) and the singularity due to the vanishing of the geometric phase lag does not exist. It is also shown that the true synchronization with non-zero eccentricity is only possible if an extra torque exists opposite to the tidal torque. The theory is developed assuming that this additional torque is produced by an equatorial permanent asymmetry in the companion. The results are model-dependent and the theory is developed only to the second degree in eccentricity and inclination (obliquity). It can easily be extended to higher orders, but formal accuracy will not be a real improvement as long as the physics of the processes leading to tidal lags is not better known.Comment: 30 pages, 7 figures, corrected typo

    Evaluation of Analytical Methods to Determine Regulatory Compliance of Coffee Leaf Tea

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    The leaves of the coffee plant Coffea are traditionally used in several countries worldwide to prepare tea-like beverages using aqueous infusion in hot water. There are currently no tested methods available to check the regulatory compliance of coffee leaf tea according to the European Union (EU) novel food authorization. This study shows that standard ISO methods for tea analysis could be transferred without modifications to coffee leaf tea analysis. The only difference found was a much lower content of some catechins in coffee leaf tea compared to Camellia sinensis tea, but the methods were clearly applicable for use in controlling the EU’s maximum limits for coffee leaf tea

    "Pfälzer Westrich" : conception for a touristic regionalization, development and marketing of a geographic region

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    Konzeption zur touristischen Regionalisierung eines semi-peripheren Raumes auf der Basis einer geo-historischen Landeskunde, Stärken-Schwächenanalyse, Tourismusmodule, Tourismusentwicklung und Maßnahmenkatalog sowie Synthesen, Visionen zu Nachbarregionen des "Europäischen Westrichs" : Ideen zur Förderung, Profilierung und Entwicklung eines ländlich strukturierten Raumes.Conception for the touristic regionalization of a semi-peripheral space based on geo-historical regional studies, strengths-weakness-analysis, tourism modules, tourism development and measurement-catalog as well as syntheses, visions to neighbour regions of the "European Westrich": Ideas to the support, image and development of a rurally structured geographic space

    Indikationsstellung und Outcome bei retrograder Anbohrung nach Hüftkopfnekrose

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