50 resultados para Kuiper belt objects


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A realistic model describing a black string-like object in an expanding Universe is analyzed in the context of the McVittie's solution of the Einstein field equations. The bulk metric near the brane is provided analogously to previous solutions for black strings. In particular, we show that at least when the Hubble parameter on the brane is positive, a black string-like object seems to play a fundamental role in the braneworld scenario, generalizing the standard black strings in the context of a dynamical brane. © 2013 Elsevier B.V.

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(10) Hygiea is the fourth largest asteroid of the main belt, by volume and mass, and it is the largest member of its family, that is made mostly by low-albedo, C-type asteroids, typical of the outer main belt. Like many other large families, it is associated with a 'halo' of objects, that extends far beyond the boundary of the core family, as detected by traditional hierarchical clustering methods (HCM) in proper element domains. Numerical simulations of the orbital evolution of family members may help in estimating the family and halo family age, and the original ejection velocity field. But, in order to minimize the errors associated with including too many interlopers, it is important to have good estimates of family membership that include available data on local asteroid taxonomy, geometrical albedo and local dynamics. For this purpose, we obtained synthetic proper elements and frequencies of asteroids in the Hygiea orbital region, with their errors. We revised the current knowledge on asteroid taxonomy, including Sloan Digital Sky Survey-Moving Object Catalog 4th release (SDSS-MOC 4) data, and geometric albedo data from Wide-field Infrared Survey Explorer (WISE) and Near-Earth Object WISE (NEOWISE). We identified asteroid family members using HCM in the domain of proper elements (a, e, sin (i)) and in the domains of proper frequencies most appropriate to study diffusion in the local web of secular resonances, and eliminated possible interlopers based on taxonomic and geometrical albedo considerations. To identify the family halo, we devised a new hierarchical clustering method in an extended domain that includes proper elements, principal components PC1, PC2 obtained based on SDSS photometric data and, for the first time, WISE and NEOWISE geometric albedo. Data on asteroid size distribution, light curves and rotations were also revised for the Hygiea family. The Hygiea family is the largest group in its region, with two smaller families in proper element domain and 18 families in various frequencies domains identified in this work for the first time. Frequency groups tend to extend vertically in the (a, sin (i)) plane and cross not only the Hygiea family but also the near C-type families of Themis and Veritas, causing a mixture of objects all of relatively low albedo in the Hygiea family area. A few high-albedo asteroids, most likely associated with the Eos family, are also present in the region. Finally, the new multidomains hierarchical clustering method allowed us to obtain a good and robust estimate of the membership of the Hygiea family halo, quite separated from other asteroids families halo in the region, and with a very limited (about 3 per cent) presence of likely interlopers. © 2013 The Author Published by Oxford University Press on behalf of the Royal Astronomical Society.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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This report of the BOOST2012 workshop presents the results of four working groups that studied key aspects of jet substructure. We discuss the potential of first-principle QCD calculations to yield a precise description of the substructure of jets and study the accuracy of state-of-the-art Monte Carlo tools. Limitations of the experiments' ability to resolve substructure are evaluated, with a focus on the impact of additional (pile-up) proton proton collisions on jet substructure performance in future LHC operating scenarios. A final section summarizes the lessons learnt from jet substructure analyses in searches for new physics in the production of boosted top quarks.

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

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

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

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

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The study area is located in the southern portion of Rio Itapicuru Greenstone Belt, Bahia, where were found rocks that belongs to the Canto Sequence, that comprises felsics and intermediary rocks, beyond metasediments. The studied maps and drill holes help to recognized stratigraphy column that was divided in three mains domains, from the base to the top: andesitics to felsics lavas domain, carbonaceous and metasedimentary domains. The data obtained in mapping and petrography analysis allows classify the area in three deformational phases, Dn, Dn+1, Dn+2. The metamorphism recognized according to the mineralogical associations permitted to classify a progressive regional metamorphism (lower to medium greenchist facies) till biotite zone, falling until chlorite zone due to retrometamorphism. The auriferous mineralizations are mainly related to hydrothermal veins included in the different lithologies, mainly in carbonaceous schists

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The area where the study was conducted is located in the central-western state of Goias. It geologically inserts the northern portion of the Greenstone Belt of Faina which belongs to the Archean terranes that fits in Brasília Fold Belt and Tocantins Structural Province. This region is known for its greenstone lode gold potential and it was heavily exploited by pioneers and prospectors, leaving many records for where they have been through. Preliminary work done by Orinoco Brasil Mineração in their required areas at the region showed that the environment is promising for gold mineralization and that the ore is controlled by structures. Therefore the objectives of this work were the geological and structural mapping in semi detail scale to improve geological, stratigraphic and structural controls present attributing possible ore understanding. With the development of the work there were recognized on the desktop three structural domains separated by a thrust fault. For each domain were discriminated the geological units ranging in gneisses, quartzites formed from coarse sediments arcoseanos, and schists. By mapping structures there were found five deformation phases, Dn-2, Dn-1, the Dn event that generated the main foliation (Sn) in high representation and two post-stages Dn with brittle late manifestations. The detail mapping of the Rattlesnake Gallery showed that the mineralized quartz vein is consistent with axial-plane foliation Sn-2 belonging to the oldest deformation Dn-2 phase and that the high grade is distributed in the hinge region folds of the same phase

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The study area is located in the geological parameters of the Pilar de Goiás Greenstone Belt (GO), it is part of the Pilar de Goias Group’s meta-volcano-sedimentary sequence. This is a homoclinal package constituted by terrigenous metassediments containing intercalations of meta-ultramafic rocks and iron formations. The units that were informally named in this work, are interpreted as belongs to the Serra do Moinho Formation. Through mineralogical associations the area’s metamorphism were classified as high greenschist facies garnet zone. Prior to this work were detected in the area, through soil samples, some auriferous anomalies. One of the objectives of this work is the detection of possibles hidrotermal alterations related to these anomalies presents in the study area

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The study area comprises Guarinos Greenstone Belt which is located in the centralwest state of Goias and has an approximate size of 280 km2. The present work has as main objective to characterize the metamorphism of the greenstone belt and the relationship between the tectonic events and the metamorphism. For the execution of the work we used data collected in the course Geological Mapping of Crystalline Area of the geology course of UNESP, classes 2009 and 2010, the data collected by Alex Choupina Joaquim Andrade Silva in his master's thesis and the information collected in field in the study area. This compilation of data allows approximately 200 thin sections have been evaluated and allowed the construction of the metamorphic map in scale 1:125.000, also allowed the preparation of the geological map in scale 1:125.000 greestone belt, based on 1:25.000 scale maps performed by students of UNESP and the mapping conducted by Silva (2011). The study area was divided into two tectonic compartments depending on the Shear Zone Engenho Velho that longitudinally crosses study area, with direction approximately NW-SE. The west compartment is bordered by granite-gneiss complex and the east compartment, seems thicker to the south and narrows gradually towards the north and its structure is seen in general as a great monoclinal with NW-SE direction with trim to SW, this way your stack was considered as a package of rocks at the base and metaultramafic metamafic the top, with a second package in tectonic contact, which is composed of detrital and chemical metasedimentary rocks. The east compartment is represented by the intrusion of a large granitic body surrounded by amphibolites and metasediments, is bounded on the east by a granite-gneiss complexes through thrust fault, and is bounded on the west by the other compartment. The structure of the compartment is seen as a major axis oriented roughly... (Completo abstract click electronic access below)

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The study area is located in the geological context of the northern portion of the Rio Itapicuru Greenstone Belt (GBRI), located northeast of the São Francisco Craton, Bahia State. The GBRI is known for its great economic potential for gold mineralization, looking south at Fazenda Brasileiro Mine and North Mine Maria Preta, is situated in the study área. The structural pattern of the northern portion of the Greenstone, theme of this work, is of great importance to understand the mineralization present. To characterize the structural model three geologic sections (scale 1:25000) were made with NW-SE and EW directions and detailing two mineralized targets, Encantado, located northwest of the area, near the city of Nordestina, and C1W, located near Itapicuru River, west of the Maria Preta mine. Thus, field work and petrographic analysis were conducted, that allow to indicate the existence of two structural domains characterized by the existence of a main foliation, low angle dipping main foliation and another with high dip angle, both with NW, moreover, folds occur in the area Dn-1 and post-Dn folds. Dn-1 folds are observed less frequently but they occur mainly forming an oblique foliation and the Sn is present in porphyroblasts observed in petrographic analysis, whereas in relation to the folds post Dn, there are more than one type of folding in area, which differ by the orientation of their axis, a post Dn NS and EW Dn another post. Moreover, two areas of metamorphic green schist (biotite zone) and medium amphibolite, which are directly related to the structural domains found

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This work consists of the implementation of the steps Define, Measure , Analyze , Improve and Control ( DMAIC ) to develop a Six Sigma project in an industry the food industry. The objective was to demonstrate a potential for reducing the occurrence of crushed cans in potting milk powder industry in a White Belt project. The food industry accounts for about 9 % of Brazil's gross domestic product ( GDP ), generating thousands of jobs . Among the major sectors of the food industry is the manufacturing sector of milk , occupies approximately 10 % of the total turnover of the food industry . Brazil is considered today one of the eight largest producers of milk powder in the world. The milk powder is packed , mostly for aluminum cans that are lined internally with varnishes and other materials to protect the milk of metals from aluminum. When the cans are dented food protection is compromised and may lead ingestion causing dis-eases such as botulism. Aiming to solve the problem of dented cans methodology was used as a case study with a quantitative approach through the DMAIC method. Some quality tools used in each step of the project as brainstorming , cause and effect diagram , flowchart , ef-fort and impact matrix, 5W1H , among other Pareto diagram is presented . A survey about the disposal of cans in the company verifying a mean loss and, from this histor-ical , a goal loss was calculated was performed . With the target set we calculated the annual saving design . During application of DMAIC was found that the highest rate of loss occurred in transportation between the factory and the factory that fills cans milk . Several actions were taken to resolve problems that resulted in dented cans and the first two months of phase control it was found that the smaller losses calculated target resulting in a saving for the company. The short time of implementa-tion of the Improve phase did not allow a more detailed a ...