Relating Weyl and diffeomorphism anomalies on super Riemann surfaces

Starting from the Wess-Zumino action associated to the super Weyl anomaly, we determine the local counterterm which allows to pass from this anomaly to the chirally split superdiffeomorphism anomaly (as defined on a compact super Riemann surface without boundary). The counterterm involves the graded extension of the Verlinde functional and the results can be applied to the study of holomorphic factorization of partition functions in superconformal field theory.Comment: (LATEX, 18 pages), MPI-Ph/92-38, LPTB 92-

Перші християнські святині Києва: біля витоків національного державотворення

The low vigour of plantlets resulting from oil palm somatic embryos may be due to insufficient levels of deposited storage proteins. Thus, in order to improve embryonic maturation and the vigour of regenerated plantlets, we investigated the effects of modifying the culture conditions with respect to the accumulation of the major oil palm storage proteins, the 7S globulins. In this study, the effect of arginine and glutamine on globulin accumulation was studied using somatic embryos of two different genotypes. Arginine and glutamine were both found to enhance protein accumulation but in different ways, which were best illustrated by measurements of soluble proteins per embryo and 7S globulin content per dry weight. Arginine increased the level of soluble proteins by 46% irrespective of the clone, and glutamine by 19% and 63% depending on the clone. The clone which accumulated the least protein in the presence of glutamine was that which contained the more protein initially. Only arginine favoured the accumulation of 7S globulin content per dry weight, irrespective of the clone considered (+26%). This study will enable further investigations of specific storage proteins as potential markers for regenerated plantlets vigour.(Résumé d'auteur

Supersymmetric structure of the induced W gravities

We derive the supersymmetric structure present in W-gravities which has been already observed in various contexts as Yang-Mills theory, topological field theories, bosonic string and chiral W_{3}-gravity. This derivation which is made in the geometrical framework of Zucchini, necessitates the introduction of an appropriate new basis of variables which replace the canonical fields and their derivatives. This construction is used, in the W_{2}-case, to deduce from the Chern-Simons action the Wess-Zumino-Polyakov action.Comment: 17 pages, Latex. To appear in Class. Quantum. Gravit

A geometrical approach to super W-induced gravities in two dimensions

A geometrical study of supergravity defined on (1|1) complex superspace is presented. This approach is based on the introduction of generalized superprojective structures extending the notions of super Riemann geometry to a kind of super W-Riemann surfaces. On these surfaces a connection is constructed. The zero curvature condition leads to the super Ward identities of the underlying supergravity. This is accomplished through the symplectic form linked to the (super)symplectic manifold of all super gauge connections. The BRST algebra is also derived from the knowledge of the super W-symmetries which are the gauge transformations of the vector bundle canonically associated to the generalized superprojective structures. We obtain the possible consistent BRST (super)anomalies and their cocycles related by the descent equations. Finally we apply our considerations to the case of supergravity.Comment: 29 pages, latex, no figures, to appear in Nucl. Phys.

The Cyst-Dividing Bacterium Ramlibacter tataouinensis TTB310 Genome Reveals a Well-Stocked Toolbox for Adaptation to a Desert Environment

Ramlibacter tataouinensis TTB310T (strain TTB310), a betaproteobacterium isolated from a semi-arid region of South Tunisia (Tataouine), is characterized by the presence of both spherical and rod-shaped cells in pure culture. Cell division of strain TTB310 occurs by the binary fission of spherical “cyst-like” cells (“cyst-cyst” division). The rod-shaped cells formed at the periphery of a colony (consisting mainly of cysts) are highly motile and colonize a new environment, where they form a new colony by reversion to cyst-like cells. This unique cell cycle of strain TTB310, with desiccation tolerant cyst-like cells capable of division and desiccation sensitive motile rods capable of dissemination, appears to be a novel adaptation for life in a hot and dry desert environment. In order to gain insights into strain TTB310's underlying genetic repertoire and possible mechanisms responsible for its unusual lifestyle, the genome of strain TTB310 was completely sequenced and subsequently annotated. The complete genome consists of a single circular chromosome of 4,070,194 bp with an average G+C content of 70.0%, the highest among the Betaproteobacteria sequenced to date, with total of 3,899 predicted coding sequences covering 92% of the genome. We found that strain TTB310 has developed a highly complex network of two-component systems, which may utilize responses to light and perhaps a rudimentary circadian hourglass to anticipate water availability at the dew time in the middle/end of the desert winter nights and thus direct the growth window to cyclic water availability times. Other interesting features of the strain TTB310 genome that appear to be important for desiccation tolerance, including intermediary metabolism compounds such as trehalose or polyhydroxyalkanoate, and signal transduction pathways, are presented and discussed

Le trotteur, un objet de puériculture dangereux (revue de la littérature sur les accidents de trotteur)

BESANCON-BU Médecine pharmacie (250562102) / SudocSudocFranceF

BA enhances the germination of oil palm somatic embryos derived from embryogenic suspension cultures

Embryogenic suspension cultures of oil palm (#Elaeis guineensis$ Jacq.) allow mass propagation of somatic embryos ; however regeneration rates are low. Histological observations have revealed that shoot development might be limited by the absence of a caulinary meristem. The addition of 6-benzyladenine during development was found to induce shoot apex differentiation and thus increased germination rates, by up to 70%. However, multiple shoot formation was a consequence of a longer period of cytokinin supply during the development of the embryo. In contrast, a short period of culture on medium with 6-benzyladenine at the beginning of embryo development was found to result in single shoot production. (Résumé d'auteur