Clues for the origin of the fundamental metallicity relations. I: The hierarchical building up of the structure

We analyse the evolutionary history of galaxies formed in a hierarchical scenario consistent with the concordance $\Lambda$-CDM model focusing on the study of the relation between their chemical and dynamical properties. Our simulations consistently describe the formation of the structure and its chemical enrichment within a cosmological context. Our results indicate that the luminosity-metallicity (LZR) and the stellar mass-metallicity (MZR) relations are naturally generated in a hierarchical scenario. Both relations are found to evolve with redshift. In the case of the MZR, the estimated evolution is weaker than that deduced from observational works by approximately 0.10 dex. We also determine a characteristic stellar mass, $M_c \approx 3 \times 10^{10} M_{\odot}$, which segregates the simulated galaxy population into two distinctive groups and which remains unchanged since $z\sim 3$, with a very weak evolution of its metallicity content. The value and role played by $M_c$ is consistent with the characteristic mass estimated from the SDSS galaxy survey by Kauffmann et al. (2004). Our findings suggest that systems with stellar masses smaller than $M_c$ are responsible for the evolution of this relation at least from $z\approx 3$. Larger systems are stellar dominated and have formed more than 50 per cent of their stars at $z \ge 2$, showing very weak evolution since this epoch. We also found bimodal metallicity and age distributions from $z\sim3$, which reflects the existence of two different galaxy populations. Although SN feedback may affect the properties of galaxies and help to shape the MZR, it is unlikely that it will significantly modify $M_c$ since, from $z=3$ this stellar mass is found in systems with circular velocities larger than 100 \kms.Comment: 17 pages, 13 figures. Minor changes to match accepted version. Accepted October 3 MNRA

Clues for the origin of the fundamental metallicity relations - I. The hierarchical building up of the structure

We analyse the evolutionary history of galaxies formed in a hierarchical scenario consistent with the concordance Lambda cold dark matter (CDM) model focusing on the study of the relation between their chemical and dynamical properties. Our simulations consistently describe the formation of the structure and its chemical enrichment within a cosmological context. Our results indicate that the luminosity–metallicity and the stellar mass–metallicity (LZR and MZR) relations are naturally generated in a hierarchical scenario. Both relations are found to evolve with redshift. In the case of the MZR, the estimated evolution is weaker than that deduced from observational works by approximately 0.10 dex. We also determine a characteristic stellar mass, Mc ≈ 3 × 1010 M⊙, which segregates the simulated galaxy population into two distinctive groups and which remains unchanged since z ∼ 3, with a very weak evolution of its metallicity content. The value and role played by Mc is consistent with the characteristic mass estimated from the SDSS galaxy survey by Kauffmann et al. Our findings suggest that systems with stellar masses smaller than Mc are responsible for the evolution of this relation at least from z ≈ 3. Larger systems are stellar dominated and have formed more than 50 per cent of their stars at z 2, showing very weak evolution since this epoch. We also found bimodal metallicity and age distributions from z ∼ 3, which reflects the existence of two different galaxy populations. Although SN feedback may affect the properties of galaxies and help to shape the MZR, it is unlikely that it will significantly modify Mc since, from z = 3 this stellar mass is found in systems with circular velocities larger than 100 km s −1Fil: de Rossi, Maria Emilia. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Tissera, Patricia Beatriz. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Scannapieco, Cecilia. Gobierno de la Republica Federal de Alemania. Max Planck Institut Fur Astrophysik; Alemania. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentin

Bone growth and sexual dimorphism at birth in intrauterine-growth-retarded rats

This paper addresses the effect of a reduction of uterine blood flow (RUB) on postcranial bone growth in rats. The objectives were: (1) to discover and characterize the changes evoked by growth retardation through a reduction in placental blood flow, (2) to see if the resulting growth retardation is different in each bone, and (3) to analyze any sex-specific features. RUB was induced by the partial bending of uterine vessels at day 1 of pregnancy. Control and sham-operated animals were also included. The animals were X-rayed at birth. The lengths and widths of the humerus, radius, and femur and pelvic length, interischial, interpubic, and pubic widths were measured. Data were analyzed by ANOVA and LSD post hoc tests. The intersubject analysis showed significant differences between groups and non-significant differences between sexes. In males, sham-operated and RUB showed significant differences in pelvic lengths and widths, and humeral, radial, femoral, and tibial widths. In females, there were significant differences only for humeral widths, radial lengths and widths, and femoral and tibial widths. We conclude that reduced blood flow delays appendicular bone growth as observed at birth. Pelvic length was more affected than that of the limbs. The widths of the pelvic and limbs bones, in turn, were more altered than the lengths, and the growth of the males more than that of the females. Partial bending of uterine vessels compromised postcranial growth, though under such disadvantageous circumstances the females proved to be more capable of growing and thus more resilient than the males.Fil: Oyhenart, Evelia Edith. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico CONICET- La Plata. Instituto de Genética Veterinaria "Ing. Fernando Noel Dulout". Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de Genética Veterinaria; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Departamento Científico de Antropología. Cátedra de Antropología Biológica IV; ArgentinaFil: Cesani Rossi, María Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico CONICET- La Plata. Instituto de Genética Veterinaria "Ing. Fernando Noel Dulout". Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de Genética Veterinaria; ArgentinaFil: Castro, Luis Eduardo. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Cátedra de Estadística; ArgentinaFil: Quintero, Fabian Anibal. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico CONICET- La Plata. Instituto de Genética Veterinaria "Ing. Fernando Noel Dulout". Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de Genética Veterinaria; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Departamento Científico de Antropología. Cátedra de Antropología Biológica IV; ArgentinaFil: Fucini, Maria Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico CONICET- La Plata. Instituto de Genética Veterinaria "Ing. Fernando Noel Dulout". Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de Genética Veterinaria; ArgentinaFil: Luna, María Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico CONICET- La Plata. Instituto de Genética Veterinaria "Ing. Fernando Noel Dulout". Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de Genética Veterinaria; ArgentinaFil: Guimarey, Luis Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico CONICET- La Plata. Instituto de Genética Veterinaria "Ing. Fernando Noel Dulout". Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de Genética Veterinaria; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; Argentina. Provincia de Buenos Aires. Ministerio de Salud. Hospital de Niños "Sor María Ludovica" de La Plata; Argentin

In search of feasting in tawantinsuyu: an analisis of the evidence from a discard Sector at el Shincal de Quimivil

El Shincal de Quimivil es considerado un sitio inkaico de gran importancia dentro del Kollasuyu, y es distinguible, dadas sus características, de otros sitios inka del NOA. Cuenta con más de un centenar de estructuras arquitectónicas residenciales y públicas, y en sus inmediaciones se hallan numerosas obras de infraestructura de riego y de cultivo, además de morteros múltiples. Estos últimos se han vinculado con la preparación de grandes cantidades de comida y bebida en momentos de ocupación inkaica en la región. La articulación de estos elementos y las grandes dimensiones de la plaza central sugieren la afluencia de personas en momentos festivos. En este trabajo se considera al estudio de la cerámica como factor particularmente significativo para dilucidar este tipo de eventos y las relaciones sociales en las que se estructuran. El análisis minucioso del conjunto cerámico recolectado en un sector definido como "zona de descarte" nos lleva a comprender aspectos de la estructura sociopolítica inkaica en un sitio plenamente articulado al Tawantinsuyu, con una dinámica propia particular que incluye, a través de las festividades, la emergencia de un espacio social para abordar la representación y manipulación de las relaciones políticas."El Shincal de Quimivil" is considered an Inka site of great importance within the Kollasuyu sector of Tawantinsuyu as it has specific characteristics that distinguish it from other late Imperial sites in Northwest Argentina. It contains over a hundred residential and public structures and, within its surroundings, their exist many irrigation structures for farming and multiple grinding mortars. These components are likely related to the preparation of large quantities of food and drink during the Inka period. The articulation of these elements, as well as the size of the central plaza, suggests that the people involved in the state-related festivities were quite affluent. In this paper the study of the associated ceramics is considered to be particularly important in elucidating such events and social relations at this site. A thorough analysis of the ceramic assemblage recovered from the sector defined as the "discard area" provides insight into various aspects of Inka sociopolitical structure at a site that was fully situated within the imperial fold of Tawantinsuyu. The study suggests that the feasting context created a particular social space and local dynamic within which the representation and manipulation of political relationships took place.Fil: Giovannetti, Marco Antonio. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Departamento Cientifico de Arqueologia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Cientifico Tecnológico La Plata; ArgentinaFil: Spina, Josefina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Arqueologia; ArgentinaFil: Paez, Maria Cecilia. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Departamento Cientifico de Arqueologia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Cientifico Tecnológico La Plata; ArgentinaFil: Cochero, Gregoria. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Departamento Cientifico de Arqueologia; ArgentinaFil: Rossi, Ariadna. Universidad Nacional de La Plata; ArgentinaFil: Esposito, Paula. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Arqueologia; Argentin

In vitro Interactions between Streptococcus intermedius and Streptococcus salivarius K12 on a Titanium Cylindrical Surface

Peri-implantitis is a steadily rising disease and is caused by oral bacterial pathogens able to form biofilm on implant surfaces and peri-implant tissues, making antibiotics treatment less effective. The use of commercial probiotics against oral pathogens could serve as an alternative to prevent biofilm formation. Streptococcus intermedius is one of the early colonizers of biofilm formation in dental implants. The aim of this study was to model the interaction between S. intermedius and Streptococcus salivarius strain K12, a probiotic bacterium producing bacteriocins. S. intermedius was co-cultured with S. salivarius K12 in an in vitro model simulating the biofilm formation in a dental implant composed by a titanium cylinder system. Biofilm formation rate was assessed by Real-Time PCR quantification of bacterial count and expression levels of luxS gene, used in response to cell density in the biofilm. Biofilm formation, bacteriocin production, luxS expression patterns were found to be already expressed within the first 12 h. More importantly, S. salivarius K12 was able to counter the biofilm formation in a titanium cylinder under the tested condition. In conclusion, our dental implant model may be useful for exploring probiotic-pathogen interaction to find an alternative to antibiotics for peri-implantitis treatment

Molecular characterization of human gastric mucosa by HR-MAS Magnetic Resonance Spectroscopy

The present study was aimed at identifying themolecular profile characteristic of the healthy humangastric mucosa.Ex vivo HR-MAS magnetic resonance spectroscopy performed at 9.4 Tesla (400.13 MHz for 1H) on gastric specimens collected during endoscopy, permits the identification of more than forty species giving a detailed picture of the biochemical pattern of the gastric tissues. These preliminary data will be used for a comparison with gastric preneoplastic and neoplastic situations. Moreover, the full knowledge of the biochemical pattern of the healthy gastrictissues is the necessary presupposition for the application of magnetic resonance spectroscopy directly in vivo