The Association of Compact Groups of Galaxies with Large-scale Structures

We use various samples of compact groups (CGs) to examine the types of association CGs have with rich and poor clusters of galaxies at low (z~0.04) and intermediate (z~0.1) redshifts. We find that ~10-20 % of CGs are associated with rich clusters and a much larger fraction with poorer clusters or loose groups. Considering the incompleteness of catalogs of poorer systems at intermediate redshift, our result is consistent with all CGs at intermediate redshift being associated with larger-scale systems. The richness of the clusters associated with CGs significantly increases from z~0.04 to z~0.1, while their Bautz-Morgan type changes from early to late type for the same range in z. Neither trend is compatible with a selection effect in the cluster catalogs used. We find earlier morphological types of galaxies to be more frequent in CGs associated with larger-scale structures, compared to those in CGs not associated to such structures. We consider this as new evidence that CGs are part of the large-scale structure formation process and that they may play an important role in the evolution of galaxies in these structures.Comment: 5 pages, no figures, Proc. ESO Workshop "Groups of galaxies in the nearby Universe", Santiago, Chile, 5-9 Dec. 2005, ESO Astrophysics Symposia, eds. I. Saviane, V. Ivanov & J. Borissova, Springer-Verlag; very minor revision of text on 15 Mar 2006, added one referenc

Degeneration rate of preantral follicles in the ovaries of goats

The degeneration rate of ovarian preantral follicles in goats, and the distribution in the follicular classes (primordial, primary or secondary) was assessed. Ovaries from adult goats were collected at a local slaughterhouse. To evaluate the morphology of the caprine preantral follicles in situ, one fragment from each ovary was fixed individually in Carnoy for 12 h, sectioned serially at a thickness of 7 μm and stained with Periodic Acid Shiff-hematoxylin. Preantral follicles were then classified according to the stage of development. Preantral follicles were classified individually either as morphologically normal; as Type 1 degenerated follicles (only the oocyte was degenerated); or as Type 2 degenerated follicles (when degeneration occurred at both oocyte and granulosa cells). The total examined was 235 primordial, 195 primary and 101 secondary follicles. The distribution of degenerated follicles as primordial, primary and secondary follicles was 8.5, 14.3 and 16.8%, respectively. When Types 1 and 2 degenerated follicles were pooled, secondary follicles were significantly more degenerated than primordial and primary follicles. When degeneration Types 1 and 2 was compared in each follicular class, a higher (P<0.05) percentage of Type 1 degeneration was observed in primordial and primary follicles. Conversely, secondary follicles were significantly more affected by Type 2 degeneration. When the follicular classes were taken together, a significantly higher percentage of Type 1 degenerated preantral follicles was observed when compared with Type 2 degenerated follicles (P<0.05). In conclusion, a low percentage of degenerated preantral follicles was observed and secondary follicles were more affected by degeneration than primordial follicles. Thus, primordial follicles constitute a large and potentially valuable source of oocytes for reproductive programs after in vitro growth and maturation

Schistosomiasis Mansoni In Urban Northeast Brazil: Influence Of Rainfall Regime On The Population Dynamics Of Biomphalaria Sp

Introduction: Our objective was to evaluate the infl uence of rainfall regime on the population dynamics of Biomphalaria in a potential urban focus of schistosomiasis in Aracaju, Brazil, during 2009-2010. Methods: Snails were collected monthly and were counted, measured and identifi ed; the level of infection and fecal contamination at the sampling sites was determined; rainfall data were obtained. Results: High levels of fecal contamination were observed, and the abundance of Biomphalaria glabrata increased during the rainy and post-rainy seasons. The snails' size was variable, and infected snails were identifi ed independently of rainfall. Conclusions: These results provide evidence of anthropogenic and climate interference in an urban focus of schistosomiasis in the Aracaju metropolitan area.465654657Pordeus, L.C., Aguiar, L.R., Quinino, L.R.M., Barbosa, C.S.A., Ocorrência das formas aguda e crônica da esquistossomose mansônica no Brasil no período de 1997 a 2006: Uma revisão de literatura (2008) Epidemiol Serv Saude, 17, pp. 163-175Souza, M.A.A., Barbosa, V.S., Wanderlei, T.N.G., Barbosa, C.S., Criadouros de Biomphalaria, temporários e permanentes, em Jaboatão dos Guararapes, PE (2008) Rev Soc Bras Med Trop, 41, pp. 252-256Araújo, K.C.G.M., Resendes, A.P.C., Souza-Santos, R., Silveira Jr., J.C., Barbosa, C.S., Análise espacial dos focos de Biomphalaria glabrata (Say, 1818) e de casos humanos de esquistossomose mansônica em Porto de Galinhas, Pernambuco, Brasil, no ano 2000 (2007) Cad Saude Publica, 23, pp. 409-417Lima, L.C., Família Planorbidae (1995) Tópicos em Malacologia Médica., pp. 90-112. , In: Barbosa FS, editor. Rio de Janeiro: Fundação Oswaldo Cruz(2005) Resolução CONAMA no 357, , http://www.cetesb.sp.gov.br/Agua/praias/res_conama_357_05.pdf, Conselho Nacional do Meio Ambiente (CONAMA). de 17 de março de. [Cited 2011 February 23]. Available fromSouza, M.A.A., Barbosa, V.S., Albuquerque, J.O., Bocanegra, S., Souza-Santos, R., Paredes, H., Aspectos ecológicos e levantamento malacológico para identificação de áreas de risco para transmissão da esquistossomose mansoni no litoral norte de Pernambuco, Brasil (2010) Iheringia Serie Zoológica, 100, pp. 19-24Barbosa, F.S., Barbosa, C.S., The bioecology of snails vectors for schistosomiasis in Brazil (1994) Cad Saude Publica, 10, pp. 200-209Fernandez, M.A., Thiengo, S.C., Susceptibility of Biomphalaria straminea from Peixe Angical dam, Tocantins, Brazil to infection with three strains of Schistosoma mansoni (2010) Mem Inst Oswaldo Cruz, 105, pp. 488-491Barbosa, C.S., Domingues, A.L.C., Abath, F., Montenegro, S.M.L., Guida, U., Carneiro, J., Epidemia de esquistossomose aguda na praia de Porto de Galinhas, Pernambuco, Brasil (2001) Cad Saude Publica, 17, pp. 725-728Rollemberg, C.V.V., Santos, C.M.B., Silva, M.M.B.L., Souza, A.M.B., Silva, A.M., Almeida, J.A.P., Aspectos epidemiológicos e distribuição geográfica da esquistossomose e geo-helmintos, no Estado de Sergipe, de acordo com os dados do Programa de Controle da Esquistossomose (2011) Rev Soc Bras Med Trop, 44, pp. 91-96Barbosa, C.S., Montenegro, S.M.L., Abath, F.G., Domingues, A.L.C., Eventos epidemiológicos relacionados à transmissão da esquistossomose em áreas rurais e urbanas de Pernambuco (2002) Mem Inst Oswaldo Cruz, 96, pp. 169-172Departamento de Vigilância Epidemiológica (2008) Vigilância e controle de moluscos de importância epidemiológica: Diretrizes técnicas., , Ministério da Saúde. Programa de Vigilância e Controle da Esquistossomose (PCE). 2nded. Brasília: Ministério da Saúd

Alternatives to Quintessence Model Building

We discuss the issue of toy model building for the dark energy component of the universe. Specifically, we consider two generic toy models recently proposed as alternatives to quintessence models, known as Cardassian expansion and the Chaplygin gas. We show that the former is enteriely equivalent to a class of quintessence models. We determine the observational constraints on the latter, coming from recent supernovae results and from the shape of the matter power spectrum. As expected, these restrict the model to a behaviour that closely matches that of a standard cosmological constant $\Lambda$.Comment: RevTex4; 7 pages, 4 figures. v2: Improved discussion of constraints on Chaplygin gas models. Other clarifications added. Phys Rev. D (in press

Correlation-Polarization Effects in Electron/Positron Scattering from Acetylene: A Comparison of Computational Models

Different computational methods are employed to evaluate elastic (rotationally summed) integral and differential cross sections for low energy (below about 10 eV) positron scattering off gas-phase C$_2$H$_2$ molecules. The computations are carried out at the static and static-plus-polarization levels for describing the interaction forces and the correlation-polarization contributions are found to be an essential component for the correct description of low-energy cross section behavior. The local model potentials derived from density functional theory (DFT) and from the distributed positron model (DPM) are found to produce very high-quality agreement with existing measurements. On the other hand, the less satisfactory agreement between the R-matrix (RM) results and measured data shows the effects of the slow convergence rate of configuration-interaction (CI) expansion methods with respect to the size of the CI-expansion. To contrast the positron scattering findings, results for electron-C$_2$H$_2$ integral and differential cross sections, calculated with both a DFT model potential and the R-matrix method, are compared and analysed around the shape resonance energy region and found to produce better internal agreement