Reflectionless measures and the Mattila-Melnikov-Verdera uniform rectifiability theorem

A new proof is given of the Mattila-Melnikov-Verdera theorem on the uniform rectifiability of an Ahlfors-David regular measure whose associated Cauchy transform operator is bounded.Comment: 31 pages, 5 figure

Transdet: a matched-filter based algorithm for transit detection - application to simulated COROT light curves

We present a matched-filter based algorithm for transit detection and its application to simulated COROT light curves. This algorithm stems from the work by Bord\'e, Rouan & L\'eger (2003). We describe the different steps we intend to take to discriminate between planets and stellar companions using the three photometric bands provided by COROT. These steps include the search for secondary transits, the search for ellipsoidal variability, and the study of transit chromaticity. We also discuss the performance of this approach in the context of blind tests organized inside the COROT exoplanet consortium.Comment: 6 pages, 4 figures, in Transiting Extrasolar Planets Workshop, meeting held in Heidelberg, 25-28 September 200

International study on <i>Artemia</i> : 24. Cold storage of live <i>Artemia</i> nauplii from various geographical sources: potentials and limits in aquaculture

Freshly-hatched Artemia nauplii from various geographical sources survived storage in a refrigerator (2-4°C) at densities of 2000 per ml and above. Except for Artemia from Chaplin Lake and Buenos Aires, naupliar viability was very high even after 48 h storage, and did not decrease significantly after a 24 h post-storage transfer to 25°C. Neither the naupliar dry weight nor biochemical composition changed significantly during refrigeration for most strains tested. Comparative culture-tests with stored and freshly-hatched nauplii as food for juvenile marine mysids Mysidopsis bahia M. and larval carp Cyprinus carpio L. revealed similar production performances

A new artificial diet for the early weaning of seabass (<i>Dicentrarchus labrax</i>) larvae

The weaning of marine fish larvae is a critical step in larval rearing. The successful transition from live food to an artificial feed depends among others on the quality of the dry feed used (e.g. freshness of ingredients, digestibility, quality of the formulation) and the larvae themselves (e.g. age, behaviour towards artificial diets, development of the digestive tract, efficiency of certain metabolic pathways). The present study shows the results obtained with a new artificial diet formulated for the weaning phase of marine fish larvae (Dicentrarchus labrax) in commercial hatcheries

Interdigitation between surface-anchored polymer chains and an elastomer : consequences for adhesion promotion

We study the adhesion between a cross-linked elastomer and a flat solid surface where polymer chains have been end-grafted. To understand the adhesive feature of such a system, one has to study both the origin of the grafted layer interdigitation with the network, and the end-grafted chains extraction out of the elastomer when it comes unstuck from the solid surface. We shall tackle here the first aspect for which we develop a partial interdigitation model that lets us analytically predict a critical surface grafting density $\sigma^{*} \simeq P^{{1/10}}N^{-{3/5}}$ beyond which the layer no longer interdigitates with the elastomer. We then relate this result with recent adhesion measurements

The use of <i>Artemia</i> in marine fish larviculture

Among the live diets used in the larviculture of fish and shellfish, the brine shrimp Artemia nauplii constitute the most widely used food item; i.e., over 700 metric tons of dry Artemia cysts are annually marketed worldwide for on-site hatching into 0.4 mm nauplii.Although the use of Artemia appears to be simple, considerable progress has been made in the past decade in improving and increasing its value as a larval diet for marine fish larvae. The improvements include: identification of the most appropriate strains and batches; new techniques for cyst disinfection; decapsulation and hatching; and enrichment and cold storage of nauplii. Using particulate or emulsified products rich in highly unsaturated fatty acids or n-3 HUFAs, the nutritional quality of Artemia can be further tailored to suit the predators' requirements by bio-encapsulating specific amounts of these products in the Artemia metanauplii. Application of the method of bioencapsulation, also called Artemia enrichment or boosting, has had a major impact on larviculture output, not only in terms of survival, growth and success of metamorphosis of the fish, but also with regard to their quality, e.g., reduced malformations, improved pigmentation and increased stress-resistance. Nonetheless, in many species survival rates are still marginal.For several marine fish species, the optimal dietary levels of n-3 HUFAs are still not met by enriched Artemia . Furthermore, while n-3 HUFAs might have proven most critical, it is very likely that other nutrients (e.g., other lipid classes, vitamins and free amino acids) might appear equally important and in some species even more critical. The bio-encapsulation technique can also be used for the oral delivery of hormones and therapeutics to the fish larvae. Artemia juveniles, grown to a size that suits the feeding behaviour of the growing predator and/or adult biomass collected from local saltworks or mass production units, can be used as an excellent nursery and weaning diet for most species of marine fish, eventually reducing fish mortalities, cannibalism and heterogeneous growth

Mid-infrared laser light nulling experiment using single-mode conductive waveguides

Aims: In the context of space interferometry missions devoted to the search of exo-Earths, this paper investigates the capabilities of new single mode conductive waveguides at providing modal filtering in an infrared and monochromatic nulling experiment; Methods: A Michelson laser interferometer with a co-axial beam combination scheme at 10.6 microns is used. After introducing a Pi phase shift using a translating mirror, dynamic and static measurements of the nulling ratio are performed in the two cases where modal filtering is implemented and suppressed. No additional active control of the wavefront errors is involved. Results: We achieve on average a statistical nulling ratio of 2.5e-4 with a 1-sigma upper limit of 6e-4, while a best null of 5.6e-5 is obtained in static mode. At the moment, the impact of external vibrations limits our ability to maintain the null to 10 to 20 seconds.; Conclusions: A positive effect of SM conductive waveguide on modal filtering has been observed in this study. Further improvement of the null should be possible with proper mechanical isolation of the setup.Comment: Accepted in A&A, 7 pages, 5 figure

The bend stiffness of S-DNA

We formulate and solve a two-state model for the elasticity of nicked, double-stranded DNA that borrows features from both the Worm Like Chain and the Bragg--Zimm model. Our model is computationally simple, and gives an excellent fit to recent experimental data through the entire overstretching transition. The fit gives the first value for the bending stiffness of the overstretched state as about 10 nm*kbt, a value quite different from either B-form or single-stranded DNA.Comment: 7 pages, 1 figur