Pb-210-derived chronology in sediment cores evidencing the anthropogenic occupation history at Corumbata River basin, Brazil

Activity profiles of excess Pb-210 combined with chemical data determined in two sediment cores from Corumbatai River basin, São Paulo State, Brazil, provided new insights into the reconstruction of historical inputs of anthropogenic constituents, contributing to improving management strategies of the hydrological resources in the basin since most of the municipalities extensively utilize the waters of Corumbatai River and tributaries for drinking purposes, among other uses. Excellent significant relationships between loss on ignition (LOI) and organic matter were found for sediments of both analyzed profiles. Silica was found to be inversely related to organic matter at both analyzed profiles: its decrease accompanied an increase in the specific surface of the sediments. This relationship was confirmed by a great number of inverse significant correlations among silica and oxides Na2O, K2O, CaO, MgO, Al2O3, P2O5, Fe2O3, MnO, and TiO2. It was possible to identify the role of organic matter on adsorption of several oxides/elements in the core sediments profiles. Apparent sediment mass accumulation rates corresponding to 224 and 802 mg cm(-2) year(-1) were obtained, and are compatible with field evidence, indicating a higher value associated with sand mining activities interfering with the natural/normal sedimentation process, due to modifications of the channel drainage.

Histological and immunohistochemical analyses of the chronology of healing process after immediate tooth replantation in incisor rat teeth

Dental tissues have special characteristics, and its regenerative capacity is noteworthy. However, understanding the circumstances that lead to regeneration is challenging. In this study, the chronology of the healing process after immediate replantation of rat incisor teeth was examined by histological and immunohistochemical analyses within a 60-day period. Thirty-six male Wistar rats had their maxillary right incisors extracted and replanted after 15min in saline storage. The rats were sacrificed immediately 3, 7, 15, 28, and 60days after replantation. The histological analysis showed rupture of the periodontal ligament and formation of a blood clot, which started being replaced by a connective tissue after 3days. At 7days, the gingival mucosa epithelium was reinserted and areas of root resorption could be seen. At 15days, the periodontal ligament was repaired. At 3days, the pulp presented an absence of the odontoblast layer, which started being replaced by a connective tissue. This tissue suffered gradual calcification, filling the root canal at 28 and 60days. The root ends were closed. The immunohistochemical analysis revealed greater expression of OP, OPG, and RANK proteins in the initial periods (0 and 3days), while TRAP expression predominated at 28 and 60days (P<0.05). In conclusion, in delayed tooth replantation, there is great new bone formation activity in the earlier periods of the repair process, while a predominance of bone resorption and remodeling is observed in the more advanced periods. © 2012 John Wiley & Sons A/S.

Dynamical evolution and chronology of the Hygiea asteroid family

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

Complex, 3D strain patterns in a synkinematic tonalite batholith from the Aracuai Neoproterozoic orogen (Eastern Brazil): Evidence from combined magnetic and isotopic chronology studies

This work combines structural and geochronological data to improve our understanding of the mechanical behaviour of continental crust involving large amount of magma or partially melted material in an abnormally hot collisional belt. We performed a magnetic and geochronological (U/Pb) study on a huge tonalitic batholith from the Neoproterozoic Aracual belt of East Brazil to determine the strain distribution through space and time. Anisotropy of magnetic susceptibility, combined with rock magnetism investigations, supports that the magnetic fabric is a good proxy of the structural fabric. Field measurements together with the magnetic fabrics highlight the presence in the batholith of four domains characterized by contrasted magmatic flow patterns. The western part is characterized by a gently dipping, orogen-parallel (similar to NS) magmatic foliation that bears down-dip lineations, in agreement with westward thrusting onto the Sao Francisco craton. Eastward, the magmatic foliation progressively turns sub-vertical with a lineation that flips from sub-horizontal to sub-vertical over short distances. This latter domain involves an elongated corridor in which the magmatic foliation is sub-horizontal and bears an orogen-parallel lineation. Finally the fourth, narrow domain displays sub-horizontal lineations on a sub-vertical magmatic foliation oblique (similar to N150 degrees E) to the trend of the belt. U/Pb dating of zircons from the various domains revealed homogeneity in age for all samples. This, together with the lack of solid-state deformation suggests that: 1) the whole batholith emplaced during a magmatic event at similar to 580 Ma, 2) the deformation occurred before complete solidification. and 3) the various fabrics are roughly contemporaneous. The complex structural pattern mapped in the studied tonalitic batholith suggests a 3D deformation of a slowly cooling, large magmatic body and its country rock. We suggest that the development of the observed 3D flow field was promoted by the low viscosity of the middle crust that turned gravitational force as an active tectonic force combining with the East-West convergence between the Sao Francisco and Congo cratons. (C) 2012 Elsevier Ltd. All rights reserved.

LAGOA SANTA REVISITED: AN OVERVIEW OF THE CHRONOLOGY, SUBSISTENCE, AND MATERIAL CULTURE OF PALEOINDIAN SITES IN EASTERN CENTRAL BRAZIL

Lagoa Santa, a karstic area in eastern Central Brazil, has been subject to research on human paleontology and archaeology for 175 years. Almost 300 Paleoindian human skeletons have been found since Danish naturalist Peter Lund's pioneering work. Even so, some critical issues such as the role of rockshelters in settlement systems, and the possible paleoclimatic implications of the peopling of the region have yet to be addressed. We present some results obtained from recent excavations at four rockshelters and two open-air sites, new dates for human Paleoindian skeletons, and a model to explain the cultural patterns observed so far. It is also argued that the Paleoindian subsistence system at Lagoa Santa was similar to other locations in South America: generalized small-game hunting complemented by fruits, seed, and root gathering.

Daily ration and feeding chronology of dominant diel vertical migrant fishes in the Subtropical Eastern North Atlantic Ocean

[EN] Diel Vertical Migrants (DVMs) are mainly zooplankton and micronekton which migrate upward from 400-500 m depth every night to feed on the productive epipelagic zone, coming back at dawn to the mesopelagic zone, where they defecate, excrete, and respire the ingested carbon. DVMs should contribute to the biological pump in the ocean and, accordingly, to the global CO2 balance. Although those migrants are mainly small fishes, cephalopods and crustaceans, the lanternfishes (myctophidae) usually contribute up to 80% of total DVMs biomass. Thus, myctophids may represent a pathway accounting for a substantial export of organic carbon to the deep ocean. However, the magnitude of this transport is still poorly known. In order to assess this active flux of carbon, we performed a preliminary study of mesopelagic organisms around the Canary Islands. Here we present the results of diet, daily rations and feeding chronology of Lobianchia dofleini, Hygophum hygomii and Ceratoscopelus maderensis, 3 dominant species of myctophids performing diel vertical migrations in the Subtropical Eastern North Atlantic Ocean. Samples were obtained on board the RV La Bocaina during June 2009. Myctophids were sorted and fixed in 4% buffered formalin and the stomach contents of target species were examined and weighted. Feeding chronology was approached by studying stomach fullness and state of digestion of prey items in individuals from hauls performed at different times and depths. Our results provide further information about lanternfishes feeding ecology in relation to their vertical migration patterns as well as their contribution to the biological carbon pump.

A Comparative Chronology of the History of Eastern Europe and the Climate

Two main areas were examined in this project: * The detailed climatic history of the second part of the Holocene (approximately the last 5500 calendar years) for the Zapadnodvinskaya lowland, making it possible to reconstruct general climatic changes in eastern Europe (taking other palynological, dendrochronological, historical and instrumental data into account). * The most important historical events for the period of the 9th-17th centuries that had an impact on Russian history. The comparative chronology of the main climatic changes and events of Russian social history showed that as local climatic conditions became worse (i.e. falling average annual temperature or precipitation rate) the density of significant events in society rose. This suggests that climatic deterioration is both a stimulus and an outstanding factor in social development.