Anomalous Pseudoscalar-Photon Vertex In and Out of Equilibrium

The anomalous pseudoscalar-photon vertex is studied in real time in and out of equilibrium in a constituent quark model. The goal is to understand the in-medium modifications of this vertex, exploring the possibility of enhanced isospin breaking by electromagnetic effects as well as the formation of neutral pion condensates in a rapid chiral phase transition in peripheral, ultrarelativistic heavy-ion collisions. In equilibrium the effective vertex is afflicted by infrared and collinear singularities that require hard thermal loop (HTL) and width corrections of the quark propagator. The resummed effective equilibrium vertex vanishes near the chiral transition in the chiral limit. In a strongly out of equilibrium chiral phase transition we find that the chiral condensate drastically modifies the quark propagators and the effective vertex. The ensuing dynamics for the neutral pion results in a potential enhancement of isospin breaking and the formation of $\pi^0$ condensates. While the anomaly equation and the axial Ward identity are not modified by the medium in or out of equilibrium, the effective real-time pseudoscalar-photon vertex is sensitive to low energy physics.Comment: Revised version to appear in Phys. Rev. D. 42 pages, 4 figures, uses Revte

Meiosis, spermatogenesis and nucleolar behavior in the seminiferous tubules of Alydidae, Coreidae and Rhopalidae (Heteroptera) species

We studied the karyotype, spermatogenesis and nucleolar activity at spermatogenesis in five species of Heteropera: Hyalymenus sp and Neomegalotomus pallescens, Alydidae; Catorhintha guttula and Hypselonotus fulvus, Coreidae; and Niesthrea sidae, Rhopalidae. They showed a red (Alydidae) or orange (Coreidae and Rhopalidae) membrane covering the testes, which consisted of seven testicular lobes, except in N. pallescens, which had only five. All the species had m-chromosomes, an X0 sex chromosome system and 10 (Hyalymenus sp, N. pallescens, and N. sidae), 16 (H. fulvus) or 22 (C. guttula) autosomes. Similar to the other species described to date, all these species showed holocentric chromosomes, interstitial chiasmata in most autosomes, and autosomes dividing reductionally in the first meiotic division and equationally in the second, while sex chromosomes, divided equationally and reductionally in the first and second meiotic divisions, respectively. In addition, we observed that the sex chromosome is heteropycnotic at prophase and that heteropycnotic chromosomal material is found in the nuclei at spermatogenesis; variation in size, shape and location of the nucleolar material occurs during spermatogenesis, denoting a variable degree of activity in the different stages

Effect of stannous chloride combined with caffeine on fecundity of Drosophila prosaltans

The present study analyzed the number of progeny of stannous chloride- and/or caffeine-treated Drosophila prosaltans. A significant decreasing effect was observed in every case when compared to the control, except for the smallest stannous chloride dose used. Combinations of both substances using two different stannous chloride doses did not differ significantly from each other but number of progeny decreased 15% with the higher concentration combination when compared with caffeine-treated flies. The present results and data in the literature indicate that the effects of continuous ingestion of stannous chloride should be studied.<br>A fecundidade de Drosophila prosaltans foi analisada em indivíduos tratados com íon estanoso, cafeína ou íon estanoso, em duas concentrações, combinado com cafeína. Em todos os casos, a fecundidade foi significativamente menor quando comparada com o controle, exceto na menor concentração de íon estanoso. Nas combinações das duas substâncias, a redução não foi significativamente maior que a causada pela cafeína sozinha, podendo indicar que o efeito das duas substâncias juntas corresponde ao próprio efeito da cafeína separada. Mas a redução da fecundidade foi 15% maior no tratamento que utilizou íon estanoso em maior concentração, sugerindo que seu efeito tóxico nesse parâmetro, mesmo em combinação com a cafeína, não deve ser desconsiderado