Opisthobranchia des Mittelmeeres

Schmekel, Luise; Portmann, Adolf

doi:10.1007/978-3-642-61817-8

Cited by 109 publications

(96 citation statements)

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“…The power is also proportional to the square of the number of particles which indicates that the radiation is coherent. Numerical simulations of electron rings based on the fully relativistic, electromagnetic particle-in-cell code OOPIC [30] recovers the main scalings found here.…”

Section: Discussionsupporting

confidence: 72%

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Bunching instability of rotating relativistic electron layers and coherent synchrotron radiation

2005

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We study the stability of a collisionless, relativistic, finite-strength, cylindrical layer of charged particles in free space by solving the linearized Vlasov-Maxwell equations and compute the power of the emitted electromagnetic waves. The layer is rotating in an external magnetic field parallel to the layer. This system is of interest to understanding the high brightness temperature of pulsars which cannot be explained by an incoherent radiation mechanism. Coherent synchrotron radiation has also been observed recently in bunch compressors used in particle accelerators. We consider equilibrium layers with a 'thermal' energy spread and therefore a non-zero radial thickness. The particles interact with their retarded electromagnetic self-fields. The effect of the betatron oscillations is retained. A short azimuthal wavelength instability is found which causes a modulation of the charge and current densities. The growth rate is found to be an increasing function of the azimuthal wavenumber, a decreasing function of the Lorentz factor, and proportional to the square root of the total number of electrons. We argue that the growth of the unstable perturbation saturates when the trapping frequency of electrons in the wave becomes comparable to the growth rate. Owing to this saturation we can predict the radiation spectrum for a given set of parameters. Our predicted brightness temperatures are proportional to the square of the number of particles and scale by the inverse five-third power of the azimuthal wavenumber which is in rough accord with the observed spectra of radio pulsars.

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Section: Discussionsupporting

confidence: 72%

“…Owing to approximation (iii), we can neglect the terms ∝ v ⊥ · δA in Eq. (30) in the evaluation of δρ and δJ φ . This is because these terms give contributions to δf which are odd functions of v r and v z .…”

Section: First Approximationmentioning

confidence: 99%

Bunching instability of rotating relativistic electron layers and coherent synchrotron radiation

2005

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“…6a) was a wider part of the duct of the receptaculum seminis. This feature, which was described as a ''loop'' by Schmekel and Portmann (1982), is corroborated by our study.…”

Section: Systematics Nudibranchia Cuvier 1817 Cladobranchia Willan Ansupporting

confidence: 89%

“…Our L. nodosa specimens clearly match the available descriptions (Haefelfinger and Stamm 1958;Templado 1982;Schmekel and Portmann 1982). Only size varies.…”

Section: Systematics Nudibranchia Cuvier 1817 Cladobranchia Willan Ansupporting

confidence: 84%

The end of a long controversy: systematics of the genus Limenandra (Mollusca: Nudibranchia: Aeolidiidae)

et al. 2013

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Limenandra Haefelfinger and Stamm 1958 is a small genus within the Aeolidiidae with, until this paper, only two species: Limenandra nodosa Haefelfinger and Stamm 1958 and Limenandra fusiformis Baba 1949. Although most recent authors have regarded Limenandra as a junior synonym of Baeolidia Bergh 1888, recent molecular studies have demonstrated its monophyletic status and have rejected the circumtropical distribution attributed to the type species, L. nodosa. The present paper reviews the previously known species of Limenandra with additional morphological data and describes three new species: Limenandra barnosii sp. nov. and Limenandra rosanae sp. nov. from the Indo-Pacific are easily distinguished from all other Limenandra species by their vivid and bright colour patterns, while Limenandra confusa sp. nov., also from the Indo-Pacific, is very similar to the Atlantic and Mediterranean L. nodosa. The five species differ in colouration, the size and ornamentation of the cerata, the rhinophorial papillae, details of the reproductive system and the number of salivary glands. Additionally, Limenandra can be easily distinguished from other Aeolidiidae based on differences in the radular and receptaculum seminis morphology.

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“…Nevertheless, Thompson & Brown (1984) and Gosliner (2004) considered them to be different species, and in particular the latter, after phylogenetic analyses, considered both species valid and required a comparison between Atlantic and Mediterranean specimens. Moreover, Schmekel & Portmann (1982) and Valdés & Ortea (1995) considered Okenia quadricornis a valid species and Okenia aspersa a junior synonym.…”

Section: Introductionmentioning

confidence: 99%

First records from the Ligurian Sea of the cold water species Okenia aspersa and Doto koenneckeri (Gastropoda: Nudibranchia)

Betti

Cattaneo‐Vietti

Bava

2015

Mar. Biodivers. Rec.

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Okenia aspersa is a north-eastern Atlantic species, only previously recorded as Okenia quadricornis from the Malta Archipelago in the Mediterranean Sea, and in juvenile forms, from Sicily and the Gulf of Naples. A second adult specimen is recorded in the present paper, which was found along the Noli Cape coast, in the western Ligurian Sea (Italy). It was found on pebbles at a depth of 10 m. In the same area, at a depth of 5.5 m, two specimens of Doto koenneckeri and three of their egg masses were found. This species, also described from Norway and Ireland, was only previously known to occur in the Mediterranean Sea off Spain and France. It is likely that the cold winter temperatures of the Ligurian Sea allowed this species to live and reproduce.

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Opisthobranchia des Mittelmeeres

Cited by 109 publications

References 0 publications

Bunching instability of rotating relativistic electron layers and coherent synchrotron radiation

Bunching instability of rotating relativistic electron layers and coherent synchrotron radiation

The end of a long controversy: systematics of the genus Limenandra (Mollusca: Nudibranchia: Aeolidiidae)

First records from the Ligurian Sea of the cold water species Okenia aspersa and Doto koenneckeri (Gastropoda: Nudibranchia)

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