First description of a histamine receptor of class 2 (HRH2) in a protochordate: expression during blastogenesis and role in regulation of ciliary beat frequency

Histaminergic receptors belong to the family of seven-transmembrane \u3b1-helix domain receptors classified in mammals into four distinct classes. Despite being widely studied in vertebrates, few data are available on the invertebrate receptors, with only predicted H1 and H2 sequences for non-chordate deuterostomes. We report the first transcript evidence of an H2 receptor for histamine in the colonial ascidian Botryllus schlosseri showing a high degree of conservation with HRH2 mammalian and other vertebrate orthologous proteins. The transcript and protein localisation during blastogenic development through in situ hybridisation and immunohistochemistry has been described. The mRNA expression appears first in the ciliary tissues of the alimentary system in filter-feeding adults and the buds, with a particular intensity in the pharynx. Transcription is activated very early, beginning from the inner layer of the disc of the secondary bud. From one generation to the next, the transcript signals become more and more intense at the level of the emergence of primordia of the branchial and peribranchial chambers and, finally, in the cells bordering the stigmata, dorsal lamina, and non-glandular ciliated zones of the endostyle. The translated H2 receptor appears as soon as the primordia of branchial and peribranchial chambers form in the secondary bud, and, in the primary buds, is found mainly in the protostigmata before the two layers of branchial and peribranchial epithelial tissue perforate to form the stigmata. In the adult zooid, the H2 receptor is expressed by ciliated mucous cells involved in food progression throughout the whole length of the alimentary canal. The observation of the effects of histamine and histamine-receptor antagonist (ranitidine) and agonist (dimaprit) drugs on explanted branchial tissue has provided confirmation concerning the receptor class and its role in regulating the ciliary beat frequency. The involvement in the local regulation of ciliary activity is of particular concern for evolutionary considerations because HRH2 seems to have been conserved in the pharynx and its developmental derivatives (e.g. upper respiratory tract and middle ear of mammals) during the evolution of chordates

Preliminary results on Ontology-based Open Data Publishing

Despite the current interest in Open Data publishing, a formal and comprehensive methodology supporting an organization in deciding which data to publish and carrying out precise procedures for publishing high-quality data, is still missing. In this paper we argue that the Ontology-based Data Management paradigm can provide a formal basis for a principled approach to publish high quality, semantically annotated Open Data. We describe two main approaches to using an ontology for this endeavor, and then we present some technical results on one of the approaches, called bottom-up, where the specification of the data to be published is given in terms of the sources, and specific techniques allow deriving suitable annotations for interpreting the published data under the light of the ontology

Studying discrete dynamical systems trough differential equations

In this paper we consider dynamical systems generated by a diffeomorphism F defined on U an open subset of R^n, and give conditions over F which imply that their dynamics can be understood by studying the flow of an associated differential equation, $\dot x=X(x),$ also defined on U. In particular the case where F has n-1 functionally independent first integrals is considered. In this case X is constructed by imposing that it shares with $F$ the same set of first integrals and that the functional equation $\mu(F(x))=\det((DF(x))\mu(x),$ for x in U has some non-zero solution. Several examples for n=2,3 are presented, most of them coming from several well-known difference equations.Comment: 22 pages; 3 Figure

The Jackiw-Pi model and its symmetries

The non-Abelian gauge model proposed by Jackiw and Pi, which generates an even-parity mass term in three space-time dimensions, is revisited in this letter. All the symmetries of the model are collected and established by means of BRS invariance and Slavnov-Taylor identity. The path for the perturbatively quantization of the Jackiw-Pi model, through the algebraic method of renormalization, is presented.Comment: 5 page

The Jackiw-Pi model: classical theory

The massive even-parity non-Abelian gauge model in three space-time dimensions proposed by Jackiw and Pi is studied at the tree-level. The propagators are computed and the spectrum consistency is analyzed, besides, the symmetries of the model are collected and established through BRS invariance and Slavnov-Taylor identity. In the Landau gauge, thanks to the antighost equations and the Slavnov-Taylor identity, two rigid symmetries are identified by means of Ward identities. It is presented here a promising path for perturbatively quantization of the Jackiw-Pi model and a hint concerning its possible quantum scale invariance is also pointed out.Comment: In honor of the 70th birthday of Prof. Olivier Piguet. 11 page

Probing the Nielsen identities

We present some comments concerning the validity of the Nielsen identities for renormalizable theories quantized in general linear covariant gauges in a context of compact gauge Lie groups.Comment: 5 pages, Revtex, eq.(8) rewritten as properly suggested by the referee, one reference updated, final version to appear in Phys.Lett.

Basin of attraction of triangular maps with applications

We consider some planar triangular maps. These maps preserve certain fibration of the plane. We assume that there exists an invariant attracting fiber and we study the limit dynamics of those points in the basin of attraction of this invariant fiber, assuming that either it contains a global attractor, or it is filled by fixed or 2-periodic points. Finally, we apply our results to a variety of examples, from particular cases of triangular systems to some planar quasi-homogeneous maps, and some multiplicative and additive difference equations, as well.Comment: 1 figur