The oldest Brazilian snakes from the cenomanian (Early Late Cretaceous)

South American Mesozoic snake diversity is mostly represented by genera from the Cenomanian (Najash), Santonian- Campanian (Dinilysia), and Campanian-Maastrichtian (Alamitophis, Patagoniophis, Rionegrophis, and Australophis) of Patagonia, Argentina. In this paper, we describe a new snake genus and species, Seismophis septentrionalis, from the Cenomanian (early Late Cretaceous) of the Alcântara Formation, Maranhão, northeastern Brazil. The new snake comprises a posteriormost trunk vertebra and possibly a poorly preserved midtrunk vertebra. Both vertebrae share small size, zygosphene moderately thick with a rectilinear roof, absence of paracotylar foramina, presence of parazygantral foramina, and strongly marked parasagittal ridges of the neural arch. The new snake is here considered of uncertain systematic affinities, but probably close to the limbed snake Najash rionegrina. Although the material is very fragmentary and the systematic assignment is still unresolved, this snake represents the oldest, as well as probably the most primitive snake from Brazil.Fil: Hsiou, Annie. Universidade de Sao Paulo; BrasilFil: Albino, Adriana Maria. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; ArgentinaFil: Medeiros, Manuel. Universidade Federal Do Maranhao; BrasilFil: Santos, Ronny. Universidade Federal Do Maranhao; Brasi

Sequential induction of NF-κB/Rel family proteins during B-cell terminal differentiation

The NF-kappa B/Rel family of at least five transcription factor polypeptides is thought to function both as a developmental regulator in B cells and as a rapid response system in all cells. To examine this notion in more detail, we determined the protein contents of both the inducible and constitutive NF-kappa B/Rel activities in a pre-B-cell line, 70Z/3, and a mature B-cell line, WEHI 231. NF-kappa B p50/p65 is the major inducible nuclear complex after lipopolysaccharide or phorbol myristate acetate treatment of 70Z/3 cells. The constitutive and inducible complexes in WEHI 231 cells are mainly composed of p50 and Rel. The constitutive or induced activities are all sensitive to I kappa B-alpha, but this inhibitor is very short-lived in WEHI 231 cells, suggesting that the balance between synthesis and degradation of I kappa B-alpha determines whether a particular cell lineage has constitutive activity. A patterned expression of the NF-kappa B/Rel activator proteins emerges from an analysis of other B-lineage cell lines and splenic B cells: mainly p50 and p65 in pre-B (and non-B) cells, a predominance of Rel and p50 in mature B cells, and expression of p52 and RelB in plasmacytoma lines. This ordered pattern of regulators may reflect the requirement for expression of different genes during terminal B-cell differentiation because different combinations of NF-kappa B/Rel family members preferentially activate distinct kappa B sites in reporter constructs

Momentum, size and value factors versus systematic co-moments in stock returns

The paper investigates the effects of firm-specific and country-specific characteristics, and the 1997Asian financial crisis on the debt maturity structure of firms in the Asia Pacific region. Given that theeconomies of the sample countries were at different stages of development and were affected by the1997 Asian financial crisis by different degrees, the paper explores the effects of the crisis on debtmaturity structure by grouping the sample countries according to the severity of the crisis. The resultsindicate that firms adjust their debt maturity structure to target level very quickly; the maturitystructure decision of a firm is the product of both its own characteristics and the economic andinstitutional environment in which it operates. They also reveal that the crisis had significant effectson firm’s debt maturity structure and their determinants