Depósito de Cu-Zn Pojuca Corpo Quatro: IOCG ou VMS?

This paper deals about the Pojuca Corpo Quatro Cu-Zn deposit, located in Carajas Mineral Province, in order to establish parameters to define its metallogenic model. The Pojuca Corpo Quatro Deposit is hosted in Igarapé Pojuca Group metavolcanossedimentary rocks, which correlates to Grão Pará Group rocks of Archean age. The metallogenic history of this deposit is complex. Two different types of ore occurrence characterize the deposit, a stratabound mineralization, consistent with the host rock banding and considered primary, and another occurring in breccias, veinlets and disseminated, as described here as a remobilized or a secondary ore. The characteristics of these different types of ore suggest two phases of mineralization, the mineralization is stratabound or primary ore, with paragenesis composed of chalcopyrite, pyrrhotite and sphalerite, is considered here as being VMS type, and remobilized or secondary ore, formed by pyrrhotite , chalcopyrite and molybdenite, described as the product of IOCG ype subsequent hydrothermal events.Este trabalho trata do depósito de Cu-Zn designado como Pojuca Corpo Quatro, localizado na Província Mineral de Carajás, e procura estabelecer parâmetros para definir seu modelo metalogenético. O Depósito Pojuca Corpo Quatro está hospedado em rochas metavulcanossedimentares do Grupo Igarapé Pojuca, correlacionáveis às rochas do Grupo Grão Pará, de idade arqueana. A história metalogenética do depósito é complexa. Duas formas diferentes de ocorrência caracterizam os minerais de minério do depósito: uma mineralização stratabound, coerente com o bandamento das rochas hospedeiras e considerada primária, e um minério em brechas, vênulas e disseminado, aqui descrito como minério remobilizado ou secundário. As características das diferentes tipologias de minério sugerem duas fases de mineralização: mineralização primária, stratabound, cuja paragênese é constituída de calcopirita, pirrotita e esfalerita, considerada neste trabalho como sendo do tipo VMS, e a mineralização secundária ou remobilizada, de paragênese formada por pirrotita, calcopirita e molibdenita, descrita como sendo produto de eventos hidrotermais posteriores do tipo IOCG

Caracterização e geocronologia SHRIMP U-Pb em zircão das rochas subvulcânicas do sistema pórfiro Yarumalito, Distrito de Marmato, Colômbia

The mining District of Marmato, located in the Central Cordillera, is considered one of the oldest gold districts in Colombia and its exploration dates back to the Inca’s times, being exploited regularly for more than a thousand years. Inserted in this context lies the Yarumalito porphyry system (YPS), characterized to concentrate ore in structure related veins and stockworks. The YPS is related to the Miocene magmatism of the Combia Formation. In this paper, the subvolcanic rocks directly associated with the mineralized zones were described in order to obtain U-Pb ages in zircon to the intrusions. Selected samples from two fertile intrusions, one andesitic (more abundant in the area) and other dioritic (more restricted), were carefully described and dated by SHRIMP. The results points to a very restricted interval for the ages, with weighted average 206Pb/238U varying from 7,00 ± 0,15 Ma for the andesitic porphyry and 6.95 ± 0.16 Ma for the dioritic porphyry. These results constrain the Yarumalito system to the final stages of the Combia magmatism and suggest a brief period for the crystallization of the mineralized subvolcanic rocks in the area and in the Marmato District.O Distrito Mineiro de Marmato, localizado na Cordilheira Central Andina, é considerado um dos mais antigos da Colômbia e as atividades de extração de ouro remontam à época dos Incas, tendo sido explorado de forma intermitente há mais de mil anos. Inserido neste contexto encontra-se o sistema pórfiro Yarumalito (SPY), caracterizado por concentrar minério em veios controlados por estruturas e stockworks. O sistema ígneo é relacionado ao magmatismo mioceno da Formação Combia. Neste trabalho foram descritas as rochas subvulcânicas diretamente relacionadas às zonas mineralizadas do SPY com o objetivo de caracterizar as intrusões e realizar datação através do método U-Pb em zircão. Amostras selecionadas de duas intrusões férteis, uma andesítica (mais abundante na área) e outra diorítica (de ocorrência mais restrita) com características intrusivas na primeira, foram criteriosamente descritas e datadas por SHRIMP na Universidade de São Paulo. Os resultados apontaram para um intervalo bastante restrito para as idades 206Pb/238U, com médias ponderadas variando de 7,00 ± 0,15 Ma para o andesito pórfiro a 6,95 ± 0,16 Ma para o diorito pórfiro. Estes resultados posicionam o sistema Yarumalito nas fases finais do magmatismo Combia e sugerem um intervalo de tempo restrito para a cristalização das intrusivas portadoras de mineralizações no Yarumalito e do Distrito de Marmato

Nuclear Factor (NF) κB polymorphism is associated with heart function in patients with heart failure

<p>Abstract</p> <p>Background</p> <p>Cardiac remodeling is generally an adverse sign and is associated with heart failure (HF) progression. NFkB, an important transcription factor involved in many cell survival pathways, has been implicated in the remodeling process, but its role in the heart is still controversial. Recently, a promoter polymorphism associated with a lesser activation of the <it>NFKB1 </it>gene was also associated with Dilated Cardiomyopathy. The purpose of this study was to evaluate the association of this polymorphism with clinical and functional characteristics of heart failure patients of different etiologies.</p> <p>Methods</p> <p>A total of 493 patients with HF and 916 individuals from a cohort of individuals from the general population were investigated. The <it>NFKB1 </it>-94 insertion/deletion ATTG polymorphism was genotyped by High Resolution Melt discrimination. Allele and genotype frequencies were compared between groups. In addition, frequencies or mean values of different phenotypes associated with cardiovascular disease were compared between genotype groups. Finally, patients were prospectively followed-up for death incidence and genotypes for the polymorphism were compared regarding disease onset and mortality incidence in HF patients.</p> <p>Results</p> <p>We did not find differences in genotype and allelic frequencies between cases and controls. Interestingly, we found an association between the ATTG₁/ATTG₁genotype with right ventricle diameter (<it>P </it>= 0.001), left ventricle diastolic diameter (P = 0.04), and ejection fraction (EF) (P = 0.016), being the genotype ATTG₁/ATTG₁more frequent in patients with EF lower than 50% (<it>P </it>= 0.01). Finally, we observed a significantly earlier disease onset in ATTG1/ATTG₁carriers.</p> <p>Conclusion</p> <p>There is no genotype or allelic association between the studied polymorphism and the occurrence of HF in the tested population. However, our data suggest that a diminished activation of <it>NFKB1</it>, previously associated with the ATTG₁/ATTG₁genotype, may act modulating on the onset of disease and, once the individual has HF, the genotype may modulate disease severity by increasing cardiac remodeling and function deterioration.</p

In vitro epithelial-to-mesenchymal transformation in human adult epicardial cells is regulated by TGFβ-signaling and WT1

Adult epicardial cells are required for endogenous cardiac repair. After myocardial injury, they are reactivated, undergo epithelial-to-mesenchymal transformation (EMT) and migrate into the injured myocardium where they generate various cell types, including coronary smooth muscle cells and cardiac interstitial fibroblasts, which contribute to cardiac repair. To understand what drives epicardial EMT, we used an in vitro model for human adult epicardial cells. These cells have an epithelium-like morphology and markedly express the cell surface marker vascular cell adhesion marker (VCAM-1). In culture, epicardial cells spontaneously undergo EMT after which the spindle-shaped cells now express endoglin. Both epicardial cells before and after EMT express the epicardial marker, Wilms tumor 1 (WT1). Adding transforming growth factor beta (TGFβ) induces loss of epithelial character and initiates the onset of mesenchymal differentiation in human adult epicardial cells. In this study, we show that TGFβ-induced EMT is dependent on type-1 TGFβ receptor activity and can be inhibited by soluble VCAM-1. We also show that epicardial-specific knockdown of Wilms tumor-1 (WT1) induces the process of EMT in human adult epicardial cells, through transcriptional regulation of platelet-derived growth factor receptor alpha (Pdgfrα), Snai1 and VCAM-1. These data provide new insights into the process of EMT in human adult epicardial cells, which might provide opportunities to develop new strategies for endogenous cell-based cardiac repair

High Proportion of Male Faeces in Jaguar Populations

Faeces provide relevant biological information which includes, with the application of genetic techniques, the sex and identity of individuals that defecated, thus providing potentially useful data on the behaviour and ecology of individuals, as well as the dynamics and structure of populations. This paper presents estimates of the sex ratio of different felid species (jaguar, Panthera onca; puma, Puma concolor; and ocelot/margay, Leopardus pardalis/Leopardus wiedi) as observed in field collected faeces, and proposes several hypotheses that could explain the strikingly high proportion of faeces from male jaguars. The proportion of male and female faeces was estimated using a non-invasive faecal sampling method in 14 study areas in Mexico and Brazil. Faecal samples were genetically analysed to identify the species, the sex and the individual (the latter only for samples identified as belonging to jaguars). Considering the three species, 72.6% of faeces (n = 493) were from males; however, there were significant differences among them, with the proportion from males being higher for jaguars than for pumas and ocelots/margays. A male-bias was consistently observed in all study areas for jaguar faeces, but not for the other species. For jaguars the trend was the same when considering the number of individuals identified (n = 68), with an average of 4.2±0.56 faeces per male and 2.0±0.36 per female. The observed faecal marking patterns might be related to the behaviour of female jaguars directed toward protecting litters from males, and in both male and female pumas, to prevent interspecific aggressions from male jaguars. The hypothesis that there are effectively more males than females in jaguar populations cannot be discarded, which could be due to the fact that females are territorial and males are not, or a tendency for males to disperse into suboptimal areas for the species. © 2012 Palomares et al

Caracterização e geocronologia SHRIMP U-Pb em zircão das rochas subvulcânicas do sistema pórfiro Yarumalito, Distrito de Marmato, Colômbia

The mining District of Marmato, located in the Central Cordillera, is considered one of the oldest gold districts in Colombia and its exploration dates back to the Inca’s times, being exploited regularly for more than a thousand years. Inserted in this context lies the Yarumalito porphyry system (YPS), characterized to concentrate ore in structure related veins and stockworks. The YPS is related to the Miocene magmatism of the Combia Formation. In this paper, the subvolcanic rocks directly associated with the mineralized zones were described in order to obtain U-Pb ages in zircon to the intrusions. Selected samples from two fertile intrusions, one andesitic (more abundant in the area) and other dioritic (more restricted), were carefully described and dated by SHRIMP. The results points to a very restricted interval for the ages, with weighted average 206Pb/238U varying from 7,00 ± 0,15 Ma for the andesitic porphyry and 6.95 ± 0.16 Ma for the dioritic porphyry. These results constrain the Yarumalito system to the final stages of the Combia magmatism and suggest a brief period for the crystallization of the mineralized subvolcanic rocks in the area and in the Marmato District.O Distrito Mineiro de Marmato, localizado na Cordilheira Central Andina, é considerado um dos mais antigos da Colômbia e as atividades de extração de ouro remontam à época dos Incas, tendo sido explorado de forma intermitente há mais de mil anos. Inserido neste contexto encontra-se o sistema pórfiro Yarumalito (SPY), caracterizado por concentrar minério em veios controlados por estruturas e stockworks. O sistema ígneo é relacionado ao magmatismo mioceno da Formação Combia. Neste trabalho foram descritas as rochas subvulcânicas diretamente relacionadas às zonas mineralizadas do SPY com o objetivo de caracterizar as intrusões e realizar datação através do método U-Pb em zircão. Amostras selecionadas de duas intrusões férteis, uma andesítica (mais abundante na área) e outra diorítica (de ocorrência mais restrita) com características intrusivas na primeira, foram criteriosamente descritas e datadas por SHRIMP na Universidade de São Paulo. Os resultados apontaram para um intervalo bastante restrito para as idades 206Pb/238U, com médias ponderadas variando de 7,00 ± 0,15 Ma para o andesito pórfiro a 6,95 ± 0,16 Ma para o diorito pórfiro. Estes resultados posicionam o sistema Yarumalito nas fases finais do magmatismo Combia e sugerem um intervalo de tempo restrito para a cristalização das intrusivas portadoras de mineralizações no Yarumalito e do Distrito de Marmato