Performance, development and use of Romanov in France

The Romanov (R) breed was imported to France in 1963. In 1987, there were 15000 purebred and 80000 FI ewes. The ewes have a high precocity and good adaptability to breeding season changes. Litter size (LS) is about 2.2 at 18 months and over 3 in adults, resulting from a high ovulation rate (OR) and a reduced embryonic mortality (EM). OR is less variable, but LS as variable as in other breeds. There are 0.8—1.9 % freemartins. In ewe lambs, the heritabilities of OR, EM and LS are 0.39, 0.09 and 0.02, resp. R has a favourable direct effect on lamb viability. Heterosis is high on fertility in ewe lambs, but less on OR and LS, favourable on lamb viability. The lack of performance regression from F1 to F4 in crosses with Berrichon du Cher has allowed the creation of a composite line (INRA 401), used on farms. Ewes suckle a maximum of twins. Lambs grow fast but have a low carcass and meat quality. A good viability of crossbred lambs and a good productivity of F1 ewes have been observed both in intensive and extensive conditions. In extensive system, R ewes are relatively susceptible to gastro-intestinal parasitism but are resistant to hepatic or pulmonary parasitism. R lambs seem to be susceptible to caseous lymphadenitis. Favourable results have been obtained with regard to prolificacy of F1 or ¼ R ewes and viability of lambs in six other European countries, but an unfavourable effect of heavy summer heat on male activity and female fertility. Composite lines have been created in Spain and Hungary

Performances de reproduction et d'élevage des brebis romanov finnoises et croisées: premier bilan des résultats obtenus en france dans les troupeaux expérimentaux de l'INRA et dans quelques troupeaux d'étude

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An alternative well-posedness property and static spacetimes with naked singularities

In the first part of this paper, we show that the Cauchy problem for wave propagation in some static spacetimes presenting a singular time-like boundary is well posed, if we only demand the waves to have finite energy, although no boundary condition is required. This feature does not come from essential self-adjointness, which is false in these cases, but from a different phenomenon that we call the alternative well-posedness property, whose origin is due to the degeneracy of the metric components near the boundary. Beyond these examples, in the second part, we characterize the type of degeneracy which leads to this phenomenon.Comment: 34 pages, 3 figures. Accepted for publication in Class. Quantum Gra

Variations génétiques de la fertilité des brebis mérinos d'arles

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Amélioration de la productivité des brebis berrichonnes du cher par croisement. III. – Performances de reproduction des trois premières genérations de brebis croisées entre les races berrichonne du cher et romanov

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Time Scale Approach for Chirp Detection

International audienceTwo different approaches for joint detection and estimation of signals embedded in stationary random noise are considered and compared, for the subclass of amplitude and frequency modulated signals. Matched filter approaches are compared to time-frequency and time scale based approaches. Particular attention is paid to the case of the so-called " power-law chirps " , characterized by monomial and polynomial amplitude and frequency functions. As target application, the problem of gravitational waves at interferometric detectors is considered

Performances de reproduction des brebis berrichonnes du cher, romanov et croisées. I. – Activité sexuelle en début de saison et a contre saison

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