Hydrodynamical simulations of Galactic fountains - II. Evolution of multiple fountains

The ejection of gas out of the disc in late-type galaxies is related to star formation and is mainly due to the explosion of Type II supernovae (SN II). In a previous paper, we considered the evolution of a single Galactic fountain, that is, a fountain powered by a single SN cluster. Using three-dimensional hydrodynamical simulations, we studied in detail the fountain flow and its dependence with several factors, such as the Galactic rotation, the distance to the Galactic centre and the presence of a hot gaseous halo. As a natural followup, this paper investigates the dynamical evolution of multiple generations of fountains generated by similar to 100 OB associations. We have considered the observed size-frequency distribution of young stellar clusters within the Galaxy in order to appropriately fuel the multiple fountains in our simulations. Most of the results of the previous paper have been confirmed, like for example the formation of intermediate velocity clouds above the disc by the multiple fountains. Also, this work confirms the localized nature of the fountain flows: the freshly ejected metals tend to fall back close to the same Galactocentric region where they are delivered. Therefore, the fountains do not change significantly the radial profile of the disc chemical abundance. The multiple fountain simulations also allowed us to consistently calculate the feedback of the star formation on the halo gas. We found that the hot gas gains about 10 per cent of all the SN II energy produced in the disc. Thus, the SN feedback more than compensate for the halo radiative losses and allow for a quasi steady-state disc-halo circulation to exist. Finally, we have also considered the possibility of mass infall from the intergalactic medium and its interaction with the clouds that are formed by the fountains. Though our simulations are not suitable to reproduce the slow rotational pattern that is typically observed in the haloes around the disc galaxies, they indicate that the presence of an external gas infall may help to slow down the rotation of the gas in the clouds and thus the amount of angular momentum that they transfer to the coronal gas, as previously suggested in the literature.

Morphology and composition of gold in a lateritic profile, Fazenda Pison ""Garimpo"", Amazon, Brazil

This study describes the morphological evolution of gold grains in a lateritic weathering profile in an equatorial rainforest climate. Primary sources of gold are quartz veins associated with shallow granophyric intrusion. Gold grains were found in fresh ore, saprolite, transition zones, ferruginous duricrust, red latosol, and yellow latosol. Irregularly shaped grains predominate, with smaller proportions of dendritic and prismatic forms. Gold grains are weathered in the uppermost 10 m of the regolith. Mean gold grain size is maximum in the duricrust (> 125 mu m) and decreases progressively upward into the yellow latosol (<90 mu m). Voids and corrosion pits appear on grain surfaces, and progressive rounding is observed from the bottom of the profile to the top. Gold grains can be classified as either homogeneous or zoned with respect to their chemical composition. Homogeneous grains contain 2-15% Ag (mean 8.3%). Zoned grains have more variable Ag contents; grain cores have means of approximately 10% or 23% Ag, with Ag-poor zones of approximately 3.7% Ag along internal discontinuities and/or outer rims. Formation of Ag-poor rims is due to preferential depletion of silver. Processes responsible for duricrust formation may preserve some grains as large aggregates, but subsequent transformation into latosol further modifies them. (c) 2007 Elsevier Ltd. All rights reserved.

Density-Profile Processes Describing Biological Signaling Networks: Almost Sure Convergence to Deterministic Trajectories

We introduce jump processes in R(k), called density-profile processes, to model biological signaling networks. Our modeling setup describes the macroscopic evolution of a finite-size spin-flip model with k types of spins with arbitrary number of internal states interacting through a non-reversible stochastic dynamics. We are mostly interested on the multi-dimensional empirical-magnetization vector in the thermodynamic limit, and prove that, within arbitrary finite time-intervals, its path converges almost surely to a deterministic trajectory determined by a first-order (non-linear) differential equation with explicit bounds on the distance between the stochastic and deterministic trajectories. As parameters of the spin-flip dynamics change, the associated dynamical system may go through bifurcations, associated to phase transitions in the statistical mechanical setting. We present a simple example of spin-flip stochastic model, associated to a synthetic biology model known as repressilator, which leads to a dynamical system with Hopf and pitchfork bifurcations. Depending on the parameter values, the magnetization random path can either converge to a unique stable fixed point, converge to one of a pair of stable fixed points, or asymptotically evolve close to a deterministic orbit in Rk. We also discuss a simple signaling pathway related to cancer research, called p53 module.

Granitic coastal geomorphology: Applying integrated terrestrial and bathymetric LiDAR with multibeam sonar to examine coastal landscape evolution

Coasts composed of resistant lithologies such as granite are generally highly resistant to erosion. They tend to evolve over multiple sea level cycles with highstands acting to remove subaerially weathered material. This often results in a landscape dominated by plunging cliffs with shore platforms rarely occurring. The long-term evolution of these landforms means that throughout the Quaternary these coasts have been variably exposed to different sea level elevations which means erosion may have been concentrated at different elevations from today. Investigations of the submarine landscape of granitic coasts have however been hindered by an inability to accurately image the nearshore morphology. Only with the advent of multibeam sonar and aerial laser surveying can topographic data now be seamlessly collected from above and below sea level. This study tests the utility of these techniques and finds that very accurate measurements can be made of the nearshore thereby allowing researchers to study the submarine profile with the same accuracy as the subaerial profile. From a combination of terrestrial and marine LiDAR data with multibeam sonar data, it is found that the morphology of granite domes is virtually unaffected by erosion at sea level. It appears that evolution of these landscapes on the coast is a very slow process with modern sea level acting only to remove subaerially weathered debris. The size and orientation of the joints determines the erosional potential of the granite. Where joints are densely spaced (<2 m apart) or the bedrock is highly weathered can semi-horizontal surfaces form.

Caracterização da dinâmica ambiental da região costeira do município de Galinhos, litoral setentrional do Rio Grande do Norte

This doctorate thesis concerning on the Characterization of the Environmental Dynamics of the Coastal Area of the Municipal district of Galinhos, Septentrional Coast of Rio Grande do Norte State, is located in the influence area of the Guamaré Petroliferous Pole, having as general objective the understanding of the active coastal dynamics in the region of Galinhos, whose specific objectives were: To study the variation of the coast line in the decades of 1954, 1967,1988, 1996, 2000, from remote sensing products; To elucidate the hypothesis of the region of Galinhos to have been an old system of islands barriers, using as basic tool the penetration radar in the soil - GPR; To monitor and to characterize the coastal dynamics of the study area starting from monthly data of beach profiles, sedimentological analysis, hydrodynamic data and environmental characterization data; which were used to feed the database of the N-NE network of Environmental Monitoring of Areas under Influence of the Petroliferous Industry;(REDE05/FINEP/CNPq/CTPETRO/ PETROBRAS). This research is justified, of the environmental point of view, by involving the mangrove ecosystem considered one of the most delicated environments of the State. From the viewpoint of the petroleum exploration, the systems of islands barriers are favorable for hydrocarbons reservoirs and, consequently important targets to the oil and gas industry, becoming this region attractive in comparison with similar lithified environments. With the results of the variability study in the position of the coast line in the Municipal district of Galinhos/RN from the analysis of remote sensing images, it was possible to investigate the changes in the coast line in temporal scale; the use of directional filters allowed to emphasize linings in the direction NE and to identify submerged features such as sandwaves. The use of GPR enabled the confirmation of paleochannels existence and thus confirmed the hypothesis that the Galinhos spit was formed from an old system of islands barriers. The results of the granulometric analyses indicated that in the summer period the sediments in the profiles A and B in the foreshore portion were classified with the granulometry of sand with scattered gravel and in the shoreface were constituted by sand, but in the winter period these same morphologic compartments were constituted by sand with sparse gravel and siltic sand respectively. In the profile C, in the summer and in the winter, the shoreface and foreshore compartments presented predominantly constituted by sand with sparse gravel. The hydrodynamic results showed that the largest wave heights were registered in the month of February (62 cm) and the highest period of 1,00 m/s in the month of May, the sense of the coastal currents was kept among the quadrants SW and NW, and the winds coming from NE were predominant. The analysis of the beach profiles demonstrated that in the profile A, although it had occurred erosion and deposition during the monitored months, the morphology of the referred profile was kept constant. In the profiles B and C, there were abrupt changes in the morphology, during the monitored months, having been identified a cyclic pattern in the features of the foreshore zone sometimes forming longitudinal sandy bars and in other times forming berm. These results evidenced, therefore, that studies of this nature are of fundamental importance for the coastal zoning, aiming subsidies to the organs managers in the closing of decisions as for the implantation of enterprises in the area, and for the industry of the petroleum through generation of information that subsidize the implementation and location of petroliferous structures adequate to this environment

Evolution of spherical non-uniform perturbations in the universe

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Petrological and geochemical evolution of the alkaline Valle Chico Massif, southeastern Uruguay

The Valle Chico Massif is a member of the Early Cretaceous alkaline magmatic suite of rocks distributed around the Parana Basin. Three magmatic associations are recognized: (1) the Plutonic Association, characterized by syenites, quartz syenites, and syenogranites; (2) the Volcanic Association, mainly composed of porphyritic quartz trachytes; and (3) the Porphyritic Dike Association consisting of rhyolites and trachytes. Judging by their geochemical behavior, the rhyolites exhibit a weak peralkaline affinity, and are genetically connected by progressive melting processes, whereas the other lithologies have a metaluminous nature, and are products of mineral fractionation. An enriched mantle of Transamazonian age, geochemically similar to OIB, is postulated as a possible source.

Sequence, evolution and ligand binding properties of mammalian Duffy antigen/receptor for chemokines

The Duffy antigen/receptor for chemokine, DARC, acts as a widely expressed promiscuous chemokine receptor and as the erythrocyte receptor for Plasmodium vivax. To gain insight into the evolution and structure/function relations of DARC, we analyzed the binding of anti-human Fy monoclonal antibodies (mAbs) and human chemokines to red blood cells (RBCs) from 11 nonhuman primates and two nonprimate mammals, and we elucidated the structures of the DARC genes from gorilla, gibbon, baboon, marmoset, tamarin, night monkey and cattle. CXCL-8 and CCL-5 chemokine binding analysis indicated that the promiscuous binding profile characteristic of DARC is conserved across species. Among three mAbs that detected the Fy6 epitope by flow cytometric analysis of human and chimpanzee RBCs, only one reacted with night monkey and squirrel monkey. Only chimpanzee RBCs bound a significant amount of the anti-Fy3 mAb. Fy3 was also poorly detected on RBCs from gorilla, baboon and rhesus monkey, but not from new world monkeys. Alignment of DARC homologous sequences allowed us to construct a phylogenetic tree in which all branchings were in accordance with current knowledge of primate phylogeny. Although DARC was expected to be under strong internal and external selection pressure, in order to maintain chemokine binding and avoid Plasmodium vivax binding, respectively, our present study did not provide arguments in favor of a selection pressure on the extracellular domains involved in ligand specificity. The amino acid variability of DARC-like polypeptides was found to be well correlated with the hydrophylicity indexes, with the highest divergence on the amino-terminal extracellular domain. Analysis of the deduced amino acid sequences highlighted the conservation of some amino acid residues, which should prove to be critical for the structural and functional properties of DARC.

Flow evolution of a metallic slurry during thixoextrusion of an automotive valve

The aim of this work is to characterize a metallic slurry (Al-4.5%Cu) flow during thixoforming of an automotive valve. The necessary globular structure was obtained by first inoculating the alloy with TIBAL (5%Ti, 1%B, Al - rest) at 750.0°C, and then reheating to a state between liquidus and solidus prior to thixoforming. Two metallic slurries, with a solid phase of approximately 86.1 and 78.2 percent, were used to generate different experimental flow patterns during the thixoforming process. The flow of the material into the die was observed for total, and partial displacement (2.7, 5.4, 7.5mm) of the punch. The first displacement shows formation of the valve rod. The patterns at each step of displacement of the punch were preserved by quenching in water, thus revealing the profile of the die fill and microstructural evolution. Degeneration of the globular phase was observed along the piece thixoextruded. Thixoextrusion forces versus time curves were generated for partial and full displacement of the punch. Porosity was visible along the billet prior to thixoforming. However, some areas show that the porosity gradually decreased to zero as the thixoextrusion pressure increased. Turbulent, transient and laminar flow are analyzed in this work.

Clinical and nutritional profile of individuals with Chagas disease

Chagas disease (CD), caused by the protozoan Trypanossoma cruzi, affects approximately 18 million individuals in the Americas, 5 million of which five in Brazil. Most chronic sufferers have either the indeterminate form of the disease, without organic compromise, or the cardiac or digestive forms. Despite the importance of this disease, there is no information on the effect of nutrition on CD evolution. We evaluated the clinical-nutritional profile of individuals with CD treated at the Tropical Diseases Nutrition Out-Patient Clinic of the Botucatu School of Medicine, UNESP.A retrospective cohort study was performed between 2002 and 2006, on 66 patients with serum and parasitological diagnosis of CD. Epidemiological, clinical, nutritional, and biochemical data were collected, including gender, age, skin color, smoking, alcoholism, physical activity, weight, stature, body mass index, abdominal circumference, glycemia, and lipid profile. Fifty-three percent were mate and 47% female; 96% were white skinned. Mean age was 49.6±6.36 years. The predominant form was indeterminate in 71 %; smoking and drinking were recorded in 23% and 17%, respectively. Sedentariness predominated in 83%, and 55% presented increased abdominal circumference. Most, 94%, were overweight or obese. The biochemical exam revealed hyperglycemia in 12% and dyslipidemia in 74%. These findings suggest that the Chagas population presents co-morbidities and risk factors for developing chronic non-transmissible diseases, including cardiovascular diseases, making CD evolution even worse. © 2007 by The Brazilian Journal of Infectious Diseases and Contexto Publishing. All rights reserved.

The ceramic artifacts in archaeological black earth (terra preta) from Lower Amazon Region, Brazil: chemistry and geochemical evolution

Neste trabalho realizou-se a caracterização química de fragmentos de artefatos cerâmicos encontrados em sítios arqueológicos com terra preta no Baixo Amazonas (Cachoeira-Porteira, Pará, Brasil), representativos da cultura Konduri (de 900 a 400 anos AP). Esses fragmentos são constituídos de SiO₂, Al₂O₃, Fe₂O₃, Na₂O e P₂O₅, sendo que SiO₂ e Al₂O₃, juntos, perfazem mais de 80 % em peso. Os teores de P₂O,₅ são relativamente elevados (2,37 % em média) sob a forma de (Al,Fe)-fosfatos, incomuns em cerâmicas vermelhas primitivas, mas encontrados em algumas cerâmicas arqueológicas egípcias e romanas. As concentrações dos elementos traços são comparáveis ou mesmo inferiores ao nível crustal, embora a composição total seja próxima a mesma. A composição química (exceto P₂O₅) em conjunto com os dados mineralógicos e texturais indicam material saprolítico derivado de rochas ígneas félsicas ou rochas sedimentares como matéria-prima das cerâmicas. Os teores de K, Ca e Na mostram que os feldspatos e fragmentos de rochas foram adicionados ao material argiloso, como sugerido pela mineralogia. Os altos teores de sílica respondem pela presença de cauixi, cariapé e/ou areias quartzosas. Fósforo deve ter sido incorporadoà matriz argilosa da cerâmica, quando do cozimento de alimentos nos vasos cerâmicos, e ainda, em parte, durante a formação do perfil de solo tipo ABE sobre Latossolos Amarelos. A matéria prima e os temperos (cauixi, cariapé, rochas trituradas e fragmentos de vasos cerâmicos descartados) encontram-se disponíveis próximos aos sítios até a atualidade, e, portanto foram a área fonte dos mesmos para a confecção dos artefatos cerâmicos.

Separation of Scaptotrigona postica Workers into Defined Task Groups by the Chemical Profile on Their Epicuticle Wax Layer

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

Evolution of Goldstone mode in binary condensate mixtures

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

Modulation of cytokines production by indomethacin acute dose during the evolution of ehrlich ascites tumor in mice

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

Chicken meat consumer profile in northwestern São Paulo State, Brazil

Brazil is the world’s first chicken meat exporter nowadays. The maintenance of this position requires a constant quality attributes evolution. This work evaluated the chicken meat consumer profile in the northwest region of São Paulo state, the most important Brazilian poultry meat consumer market, in order to provide information to the productive sector. The data were collected using 482 interviews and questionnaires that were answered by e-mail. The questionnaires involved questions related to the consumer identification, habits and preferences and their knowledge about food safety, production system, sustainability and animal welfare. Most of the consumers, 62%, were female, with ages ranging from 20 to 50 years. Beef was preferred by the majority of the answerers and chicken and pork meat were together the second choice. Only 2% of the interviewed consumers mentioned not enjoying poultry meat. The main part of consumers, 67%, prefer to buy breast and leg cuts and only 11% are used to buy the whole poultry carcass. More than 60% of the interviewed have already eaten free range chicken meat, but the majority of them, 89%, are used to consume regular industrialized poultry. About 75% of the consumers believe hormones are used to grow the birds. Over 80% of people observe the expiration date before buying the product, but only 55% check if it has the stamp of the official inspection service. Color and appearance of meat are the most important factors that influence the consumer’s choice. The amount of water that drips on the tray is a rejection factor to 88% of answerers. Most of them, 66%, prefer lighter colored meat. Only 27% of them believe that chicken meat causes an environmental impact and 48% do not know the meaning of animal welfare. More than half of the interviewed do not consider animal welfare aspects before consuming any kind of meat. From these results obtained, it is possible to conclude that any effort to improve the product quality, mainly concerned to animal welfare and sustainability aspects, requires prior educational initiatives.