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We study the geometry of lightlike submanifolds (M, g, S(TM), S(TM⊥)) of a semi-Riemannian manifold ( ..., ....) of quasiconstant curvature subject to the following conditions: (1) the curvature vector field ζ of ... is tangent to M, (2) the screen distribution S(TM) of M is totally geodesic in M, and (3) the coscreen distribution S(TM⊥) of Mis a conformal Killing distribution. [ABSTRACT FROM AUTHOR]

We have studied local magnetization reversal by laser annealing in exchange biased NiFe/FeMn bilayer. Local magnetization reversal was performed by using the Nd:YAG laser under external magnetic field. When the laser illuminated the patterned film with the power of above 300 mW during 15 min, a magnetoresistance (MR) curve with symmetric peaks at the opposite field was obtained due to the local reversal of exchange biasing. A similar result was observed in NiFe/FeMn/NiFe trilayer. As the exposed area expanded, the intensity of opposite MR peak increased. The direction of exchange anisotropy in the partially reversed region can be restored by local laser annealing under alternating magnetic field, even if its MR peak was reduced by the damage and interdiffusion. The magnetic new domain structures of the partially reversed region was generated by laser annealing near the exposed area. [ABSTRACT FROM AUTHOR]

A Lancefield serological group CStreptococcussp. was isolated from cultured amberjack,Seriola dumeriliRisso, and yellowtail,Seriola quinqueradiataTemminck and Schlegel, immunized withLactococcus garvieaecommercial vaccines in Japan. The isolated bacteria were Gram-positive cocci, auto-aggregating in saline, morphologically long chains in growth medium, catalase negative andα-haemolytic on blood agar. An almost complete gene sequence of the 16S rDNA of two isolates was determined and compared with that of bacterial strains in the database. The isolates were identified asStreptococcus dysgalactiaebased on the results of the 16S rDNA sequence, the bacteriological properties and the Lancefield serological grouping. Oligonucleotide primers specifically designed for the 16S–23S rDNA intergenic spacer region ofS. dysgalactiaeamplified a gene from all the fish isolates, as well as the type strainsα-haemolyticS. dysgalactiaesubsp.dysgalactiaeATCC430738 andβ-haemolyticS. dysgalactiaesubsp.equisimilisATCC35666, but not those ofS. equiATCC33398,Lactococcus garvieaeATCC43921 andL. garvieaeKG9408. The severe necrotic lesions of the caudal peduncle seen in experimentally infected fish were similar to those seen in naturally infected fish. [ABSTRACT FROM AUTHOR]

A survey of mtDNA variation among populations of chum salmon Oncorhynchus keta around the Pacific Rim revealed four large population groups: Rim of the Sea of Japan, the Rim of the Okhotsk Sea and West Bering Sea, North-west Alaska and Gulf of Alaska. The observed population structure appears to reflect isolation by distance with limited gene flow between regions and larger amounts of gene flow between populations within these four regions. [ABSTRACT FROM AUTHOR]