Quebra de Simetria no Universo Primordial

Pós-graduação em Física - IFT

Equação de Estado para o Universo Primordial

Pós-graduação em Física - IFT

Equações de estado exóticas na equação de Einstein

Pós-graduação em Física - IFT

Complex scalar dark matter in a B-L model

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

A geometric approach to cosmological boundary conditions

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Tópicos em teoria das perturbações cosmológicas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Viability of primordial follicles derived from cryopreserved ovine ovarian cortex tissue

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Testosterone-immunopositive primordial germ cells in the testis of the bullfrog, Rana catesbeiana

In amphibia, steroidogenesis remains quiescent in distinct seasonal periods, but the mechanism by which spermatogenesis is maintained under low steroidogenic conditions is not clear. In the present study, testosterone location in the testes of Rana catesbeiana was investigated immunohistochemically during breeding (summer) and nonbreeding (winter) periods. In winter, the scarce interstitial tissue exhibited occasional testosterone immunopositivity in the interstitial cells but the cytoplasm of primordial germ cells (PG cells) was clearly immunopositive. By contrast, in summer, PG cells contained little or no immunoreactivity whereas strong immunolabelling was present in the well-developed interstitial tissue. These results suggest that PG cells could retain testosterone during winter. This androgen reservoir could be involved in the control of early spermatogenesis in winter and/or to guarantee spermiogenesis and spermiation in the next spring/summer. The weak or negative immunoreaction in the summer PG cells might reflect consumption of androgen reservoir by the intense spermatogenic activity from spring to summer. Thus, besides acting as stem cells, PG cells of R. catesbeiana could exert an androgen regulatory role during seasonal spermatogenesis.

Signatures of primordial non-Gaussianities in the matter power-spectrum and bispectrum: the time-RG approach

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Sociedade civil, entre o político-estatal e o universo gerencial

Cet article est fondé sur le concept de société civile développé par le marxiste Antonio Gramsci et propose un dialogue critique avec les autres idées de la société civile qui, de nos jours, cherchent à s'affirmer dans le panorama politique et culturel. Nous nous fondons sur le fait d'être passé, au cours des dernières décennies, d'une idée de société civile prioritairement politique-publique, scène de luttes démocratiques et de nouvelles hégémonies, vers une image qui transforme la société civile soit en ressource de gestion ­ un arrangement de la société destiné à rendre possible différents genres spécifiques de politiques publiques ­ soit en un facteur de reconstruction étique et dialogique de la vie sociale. L'incorporation de l'idée de participation au langage de planification a déplacé la société civile de son champs principal (celui de l'organisation de nouvelles hégémonies) vers un espace de coopération et de gestion de la crise. Par ailleurs, l'expansion de l'activisme social, dans un cadre de crise politique de l'État et de la démocratie représentative a poussé vers la recherche d'une autre «place» à partir de laquelle il serait possible d'établir et de répandre de nouvelles postulations éthiques et de nouvelles procédures collectives. D'une phase où le marxisme était prépondérant et laissait sa marque, nous sommes entrés dans une phase dans laquelle la perspective libérale, affirmée de façon orthodoxe ou nuancée, prévaut et opère comme principale référence.

Early Development and Putative Primordial Germ Cells Characterization in Dogs

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effects of the planetary migration on some primordial satellites of the outer planets

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Entusiastas da cultura: o universo do livro e suas representações nas cartas do Centro Cultural Euclides da Cunha

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Ultrastructure of sheep primordial follicles cultured in the presence of indol acetic acid, EGF, and FSH

The aim of this study was to investigate the ultrastructural characteristics of primordial follicles after culturing of sheep ovarian cortical slices in the presence of indol acetic acid (IAA), Epidermal Growth Factor (EGF), and FSH. To evaluate ultrastructure of primordial follicles cultured in MEM (control) or in MEM containing IAA, EGF, and FSH, fragments of cultured tissue were processes for transmission electron microscopy. Except in the control, primordial follicles cultured in supplemented media for 6d were ultrastructurally normal. They had oocyte with intact nucleus and the cytoplasm contained heterogeneous-sized lipid droplets and numerous round or elongated mitochondria with intact parallel cristae were observed. Rough endoplasmic reticulum (RER) was rarely found. The granulosa cells cytoplasm contained a great number of mitochondria and abundant RER. In conclusion, the presence of IAA, EGF, and FSH helped to maintain ultrastructural integrity of sheep primordial follicles cultured in vitro. © 2011 Evelyn Rabelo Andrade et al.

Primordial germ cells (spermatogonial stem cells) of bullfrogs express sex hormone-binding globulin and steroid receptors during seasonal spermatogenesis

In vertebrate species, testosterone seems to inhibit spermatogonial differentiation and proliferation. However, this androgen can also be converted, via aromatase, into estrogen which stimulates spermatogonial differentiation and mitotic activity. During seasonal spermatogenesis of adult bullfrogs Lithobates catesbeianus, primordial germ cells (PGCs) show enhanced testosterone cytoplasm immunoexpression in winter; however, in summer, weak or no testosterone immunolabelling was observed. The aim of this study was to confirm if PGCs express stem cell markers-alkaline phosphatase (AP) activity and GFRα1 (glial-cell-line-derived neurotrophic factor)-and verify whether testosterone is maintained in these cells by androgen receptors (ARs) and/or sex hormone-binding globulin (SHBG) in winter. Furthermore, regarding the possibility that testosterone is converted into estrogen by PGCs in summer, the immunoexpression of estrogen receptor (ER)β was investigated. Bullfrog testes were collected in winter and in summer and were embedded in glycol methacrylate for morphological analyses or in paraffin for the histochemical detection of AP activity. GFRα1, AR, SHBG and ERβ expression were detected by Western blot and immunohistochemical analyses. The expression of AP activity and GFRα1 in the PGCs suggest that these cells are spermatogonial stem cells. In winter, the cytoplasmic immunoexpression of ARs and SHBG in the PGCs indicates that testosterone is maintained by these proteins in these cells. The cytoplasmic immunoexpression of ERβ, in summer, also points to an ER-mediated action of estrogen in PGCs. The results indicate a participation of testosterone and estrogen in the control of the primordial spermatogonia during the seasonal spermatogenesis of L. catesbeianus. © 2012 S. Karger AG, Basel.