Estudo geoquímico e geocronológico Rb-Sr e Sm-Nd em zonas de cisalhamento mineralizadas em ouro e suas relações com as rochas encaixantes e geocronológico Sm-Nd em mineralizações de scheelita na faixa Seridó

Great part of the gold mineralizations are associated with shearing zones through which circulate a great volume of fluids, that interact with the host rocks, originating leaching or precipitation of chemical elements, including gold. The studied mineralizations are inserted in the Seridó Belt. The tungsten mineralization in Brejuí Mine is hosted in calcsilicate rocks from Jucurutu Formation. The São Francisco auriferous mineralization has as host rocks mica-schists from Seridó Formation, while the Ponta da Serra and Fazenda Simpático mineralizations are hosted in orthogneisses of this fold belt basement. The research conducted on these mineralizations had the purpose of integrate the data of chemical elements behavior during the shearing/mineralizing event, and its influence on the isotopic systems Rb-Sr and Sm-Nd. The studies of chemical mobility in the auriferous mineralizations showed that elements that during the shearing displayed in general an immobile behavior were Al, Ti and Zr. Among the elements that were mobilized during the event, K and Rb showed mass gain in ali belts of transformed rocks, while the elements Ca, Na and Sr normally lost mass. Petrographic studies showed that the minerais biotite and plagioclase, in all investigated mineralizations, played an important role in the chemical reactions occurred in the transformed rocks to the generation of muscovite, cordierite and sillimanite, justifying the input of K to the formation of muscovite, and the release of Na and Ca from plagioclase to the fluid phase. In the São Francisco auriferous mineralization, the results of the Rb-Sr isotopic analysis yielded ages of 645 ± 19 Ma and 596 ± 17 Ma, with both samples, from original and transformed rocks. Two ages, 569 ± 20 Ma. and 554 ± 19 Ma., were obtained with samples frem the transformed rocks domain. These ages suggest that there were two metamorphic pulses during the emplacement of the mineralized shearing zone. The Sm-Nd data yielded TDM ages of 1,31 Ga and 1,26 Ga with 3Nd (0,6 Ga) of -0,26 e -0,40 for the original and final transformed rocks, respectively. In case of the orthogneisses of Caicó Complex, e.g. the Ponta da Serra and Fazenda Simpático mineralizations, the Rb-Sr data did not yield ages with geological significance. In the Ponta da Serra mineralization, the Sm-Nd isotopic data yielded T DM ages of 2,56 Ga and 2,63 Ga to the original rocks and of 2,71 Ga to the mineralized sheared rock, and values of 3Nd (2,0 Ga) between -3,70 e -5,42 to the original and sheared rock, respectively. In the Fazenda Simpático, Sm-Nd data yielded TDM between 2,65 and 2,69 Ga with values of 3Nd (2,0 Ga) between -5,25 e -5,52. Considering the Sm-Nd data, the TDM ages may be admitted as the age of the parental magma extraction, producer of the protoliths of the orthogneisses from Ponta da Serra and Fazenda Simpático mineralizations. The chemical mobility studies showed that in the basement hosted mineralizations, Rb achieved mass while Sr lost mass, as Sm as well as Nd were strongly mobilized. The Sm/Nd ratio remained constant, however, confirming the isochemical character of those elements. In the basement mineralizations, Rb-Sr ages are destituted of geological significance, because of the partial opening of the isotopic system during the tectono-metamorphic transformations. In the tungsten mineralization, the diagram Sm-Nd constructed with the whole-rock data of calcsilicatic and the high-temperature paragenesis (garnet, diopside and iron-pargasitic hornblende) indicated an 631 ± 24 Ma age, while with the whole-rock data and low-temperature paragenesis (vesuvianite, epidote and calcite), a 537 ± 107 Ma age was obtained. These ages, associated with the petrographic observations, suggest that there was a time gap among the hydrothernal events responsible by the formation of the high and low temperature paragenesis in the calcsilicatic rocks mineralized in scheelite

Características ópticas e morfológicas de nanoestruturas de ouro

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

Determinação dos parâmetros cinéticos e termodinâmicos da adsorção de L-cisteína em ouro por meio da técnica de microbalança a cristal de quartzo

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

Avaliação da limpeza de CDtrodo construídos a partir de CD de ouro gravável/fita adesiva de galvanoplastia

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

Acupuntura e implante de fragmentos de ouro em pontos de acupuntura e pontos Acupuntura e implante de fragmentos de ouro em pontos de acupuntura e pontos gatilho para o tratamento de displasia coxo-femoral em Pastor Alemão

Background: Canine hip dysplasia (HD) is characterized by hip joint laxity and subluxation. It is the most common cause of osteoarthritis in dogs, especially in larger breeds. Its management includes nutritional supplements, nonsteroidal anti-inflammatory drugs, physical therapy, acupuncture or surgical procedures. Implantation of gold beads in acupuncture points and trigger points around a joint has been used in the treatment of osteoarthritis in dogs for at least 30 years. Gold bead implants(GBI) acts as continuous acupuncture stimulation and trigger point treatment in canine HD with long lasting results. Electrophysiological investigations of trigger points reveal dysfunctional muscle spindles which indicate that the electrical activity of active loci arises from extrafusal motor endplates.Case: This is a report on the use of acupuncture and GBI for bilateral HD in a nine year old female German Shepherd. The patient has a HD non-responsive to anti-inflammatory drugs and was unable to stand up or walk by its own. Radiographs showed marked dysplasia, significant subluxation with the femoral head partly out of a shallow acetabulum and massive secondary arthritic bone changes, mainly on the right side. The animal was submitted to eight acupuncture sessions with seven days interval. After the first acupuncture session the use of NSAID was interrupted. After eight weeks the dog was considered rehabilitated and underwent GBI in acupoints and trigger points as maintenance treatment. During the one-year follow-up period the improvement remained unchanged with no need of analgesics.Discussion: It has been suggested that acupuncture or GBI can treat the chronic pain resulting from osteoarthritis induced by HD. According to AP theory, GBI is permanent and long-lasting acupoint stimulation. Moreover, the method is inexpensive, quick and easy to perform, with no postoperative pain or need of exercise restriction. Although gold is extremely corrosion-resistant, the surface of the gold implants stimulates a reaction from the immune system causing an oxidative liberation of gold ions with anti-inflammatory actions. It is well known that gold ions are effective inhibitors of the respiratory burst of neutrophils and monocytes and the proliferation of lymphocytes. These findings suggest that gold implantation, on a local scale, mimics the anti-inflammatory and pain-relieving effect of drugs with chemically bound gold ions. The relatively slow speed of the process results in a limited liberation of gold ions securing that they are taken up almost exclusively by cells close to the implant. The nine year old female German shepherd had a positive response to acupuncture with pain relieve and locomotor rehabilitation. For the nine year old female German shepherd previous acupuncture sessions to GBI resulted in no post-implant worsening period. Indeed, the association acupuncture/GBI does not have the anti-inflammatory drugs undesirable effects and brings long lasting results. In conclusion, GBI therefore should be considered for canine HD when conservative or medical treatments fail to give the desired effect.

Acurácia do teste de escada utilizando o consumo máximo de oxigênio como padrão-ouro

Objective: To determine the accuracy of the variables related to the fixed-height stair-climbing test (SCT) using maximal oxygen uptake (V̇O 2 max) as the gold standard. Methods: The SCT was performed on a staircase consisting of 6 flights (72 steps; 12.16 m total height), with verbal encouragement, in 51 patients. Stair-climbing time was measured, the variables 'work' and 'power' also being calculated. The V̇O2 max was measured using ergospirometry according to the Balke protocol. We calculated the Pearson linear correlation (r), as well as the values of p, between the SCT variables and V̇O2 max. To determine accuracy, the V̇O 2 max cut-off point was set at 25 mL/kg/min, and individuals were classified as normal or altered. The cut-off points for the SCT variables were determined using the receiver operating characteristic curve. The Kappa statistic (k) was used in order to assess concordance. Results: The following values were obtained for the variable 'time': cut-off point = 40 s; mean = 41 ± 15.5 s; r = -0.707; p < 0.005; specificity = 89%; sensibility = 83%; accuracy = 86%; and k = 0.724. For 'power', the values obtained were as follows: cut-off point = 200 w; mean = 222.3 ± 95.2 w; r = 0.515; p < 0.005; specificity = 67%; sensibility= 75%; accuracy = 71%; and k = 0.414. Since the correlation between the variable 'work' and V̇O2 max was not significant, that variable was discarded. Conclusion: Of the SCT variables tested, using V̇O2 max as the gold standard, the variable 'time' was the most accurate.

Cavas históricas de ouro do Jaraguá: o que resta para se preservar?

The Historical Jaraguá Gold Caves are vestiges of excavations in weathered rock, dating back to the Brazilian colonial times, situated NW of Jaraguá peak, in the São Paulo municipality (SP). The areas were investigated to support historical preservation innitiatives. The excavations have lateral steep slopes and a narrow fat bottom zone, occupied by dense vegetation. The trace of the excavations is sinuous, trending N40-50W, in accordance to a transition zone of Neoproterozoic rocks: metapelites and metapsamites by the SW side and calc-silicate rocks and amphybolites at NE. The structural control results from three successive deformation phases. Urban expansion and road construction, during the last 30 years, have strongly impacted the areas: (I) Base of Quebra-Pé hill; (II) Jardim Britânia; (III) Morro Doce; (IV) Nova Anhangüera Park. A 5 th site was disfgured by earthworks. The Jardim Britânia area is partly discharacterized by earthflls; this however does not impede further protection actions. This framework allows to recommend authorities: (1) to permit immediate preservation of these areas; (2) to develop programs to build an integrated site for scientifc diffusion or an educational center for exhibition of rocks, ores and mineral samples; (3) to support the interest of some owners to preserve the area called Morro Doce, (4) to put forward a few proposals for educational use of the excavations, by production of feld guides on the historic sites. The alternatives will help keeping alive the memory of mining in the São Paulo State.

O olhar do fotógrafo Luiz Fontana: documentação de ouro preto (1930-1960) - fotografia e arte pública : um estudo de caso

Pós-graduação em Artes - IA

Síntese e caracterização de intermetálicos ordenados binários de ouro: potenciais eletrocatalisadores de reações em células à combustível

Pós-graduação em Ciência e Tecnologia de Materiais - FC

Explorando a matemática do número Ф, o número de ouro

Pós-graduação em Matemática em Rede Nacional - IBILCE

Gestión urbana en ciudades intermedias: relatório final: Ouro Preto

Incluye Bibliografía

Análisis comparativo de la gestión urbana en las ciudades intermedias de Cusco, Manizales, Ouro Preto, Puerto España y Valdivia

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Sistema integrado de combate a pobreza em Ouro Preto, Brasil

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Determinação das condições de ataque químico seletivo para alteração de composição superficial de ligas de ouro

Pós-graduação em Engenharia Mecânica - FEG

Identificação e análise das áreas domicilares do boto-cinza, Sotalia guianensis (Van Bénéden, 1864), no estuário de Cananéia, São Paulo

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