2,374 research outputs found
Are young sea bass, Dicentrarchus labrax L. (Teleostei : Pisces) adapted to mussel cultures?
In Mont Saint-Michel Bay, one of the most abundant food items in young sea bass diets was Mytilus edulis. This invertebrate is an abundant cultured bivalve in many coastal systems and it is known to be in direct trophic competition with the natural food items of sea bass. This study shows that mussel culture can play the role of a nursery area, providing food for young opportunistic fish. Quantification of these interactions appears to be of a major importance in order to enable sustainable management of coastal areas
Isometric extensions of Anosov flows via microlocal analysis
The aim of this note is to revisit the classical framework developed by Brin,
Pesin and others to study ergodicity and mixing properties of isometric
extensions of volume-preserving Anosov flows, using the microlocal framework
developed in the theory of Pollicott-Ruelle resonances. The approach developed
in the present note is reinvested in the companion paper [arXiv:2111.14811] in
order to show ergodicity of the frame flow on negatively-curved Riemannian
manifolds under nearly -pinched curvature assumption (resp. nearly
-pinched) in dimension and (resp. dimension
).Comment: 29 page
Absolute measurement of the nitrogen fluorescence yield in air between 300 and 430 nm
The nitrogen fluorescence induced in air is used to detect ultra-high energy
cosmic rays and to measure their energy. The precise knowledge of the absolute
fluorescence yield is the key quantity to improve the accuracy on the cosmic
ray energy. The total yield has been measured in dry air using a 90Sr source
and a [300-430 nm] filter. The fluorescence yield in air is 4.23 0.20
photons per meter when normalized to 760 mmHg, 15 degrees C and with an
electron energy of 0.85 MeV. This result is consistent with previous
experiments made at various energies, but with an accuracy improved by a factor
of about 3. For the first time, the absolute continuous spectrum of nitrogen
excited by 90Sr electrons has also been measured with a spectrometer. Details
of this experiment are given in one of the author's PhD thesis [32].Comment: accepted for publication in NIM
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