Different mineralization styles in a volcanic-hosted ore deposit: the fluid and isotopic signatures of the Mt Morgan Au-Cu deposit, Australia

Quantitative laser ablation (LA)-ICP-MS analyses of fluid inclusions, trace element chemistry of sulfides, stable isotope (S), and Pb isotopes have been used to discriminate the formation of two contrasting mineralization styles and to evaluate the origin of the Cu and Au at Mt Morgan. The Mt Morgan Au-Cu deposit is hosted by Devonian felsic volcanic rocks that have been intruded by multiple phases of the Mt Morgan Tonalite, a low-K, low-Al2O3 tonalite-trondhjemite-dacite (TTD) complex. An early, barren massive sulfide mineralization with stringer veins is conforming to VHMS sub-seafloor replacement processes, whereas the high-grade Au-Cu. ore is associated with a later quartz-chalcopyrite-pyrite stock work mineralization that is related to intrusive phases of the Tonalite complex. LA-ICP-MS fluid inclusion analyses reveal high As (avg. 8850 ppm) and Sb (avg. 140 ppm) for the Au-Cu mineralization and 5 to 10 times higher Cu concentration than in the fluids associated with the massive pyrite mineralization. Overall, the hydrothermal system of Mt Morgan is characterized by low average fluid salinities in both mineralization styles (45-80% seawater salinity) and temperatures of 210 to 270 degreesC estimated from fluid inclusions. Laser Raman Spectroscopic analysis indicates a consistent and uniform array Of CO2-bearing fluids. Comparison with active submarine hydrothermal vents shows an enrichment of the Mt Morgan fluids in base metals. Therefore, a seawater-dominated fluid is assumed for the barren massive sulfide mineralization, whereas magmatic volatile contributions are implied for the intrusive related mineralization. Condensation of magmatic vapor into a seawater-dominated environment explains the CO2 occurrence, the low salinities, and the enriched base and precious metal fluid composition that is associated with the Au-Cu. mineralization. The sulfur isotope signature of pyrite and chalcopyrite is composed of fractionated Devonian seawater and oxidized magmatic fluids or remobilized sulfur from existing sulfides. Pb isotopes indicate that Au and Cu. originated from the Mt Morgan intrusions and a particular volcanic strata that shows elevated Cu background. (C) 2002 Elsevier Science B.V. All rights reserved.

Applications of accurate, high-precision Pb isotope ratio measurement by multi-collector ICP-MS

The isotope composition of Ph is difficult to determine accurately due to the lack of a stable normalisation ratio. Double and triple-spike addition techniques provide one solution and presently yield the most accurate measurements. A number of recent studies have claimed that improved accuracy and precision could also be achieved by multi-collector ICP-MS (MC-ICP-MS) Pb-isotope analysis using the addition of Tl of known isotope composition to Pb samples. In this paper, we verify whether the known isotope composition of Tl can be used for correction of mass discrimination of Pb with an extensive dataset for the NIST standard SRM 981, comparison of MC-ICP-MS with TIMS data, and comparison with three isochrons from different geological environments. When all our NIST SRM 981 data are normalised with one constant Tl-205/Tl-203 of 2.38869, the following averages and reproducibilities were obtained: Pb-207/Pb-206=0.91461+/-18; Pb-208/Ph-206 = 2.1674+/-7; and (PbPh)-Pb-206-Ph-204 = 16.941+/-6. These two sigma standard deviations of the mean correspond to 149, 330, and 374 ppm, respectively. Accuracies relative to triple-spike values are 149, 157, and 52 ppm, respectively, and thus well within uncertainties. The largest component of the uncertainties stems from the Ph data alone and is not caused by differential mass discrimination behaviour of Ph and Tl. In routine operation, variation of sample introduction memory and production of isobaric molecular interferences in the spectrometer's collision cell currently appear to be the ultimate limitation to better reproducibility. Comparative study of five different datasets from actual samples (bullets, international rock standards, carbonates, metamorphic minerals, and sulphide minerals) demonstrates that in most cases geological scatter of the sample exceeds the achieved analytical reproducibility. We observe good agreement between TIMS and MC-ICP-MS data for international rock standards but find that such comparison does not constitute the ultimate. test for the validity of the MC-ICP-MS technique. Two attempted isochrons resulted in geological scatter (in one case small) in excess of analytical reproducibility. However, in one case (leached Great Dyke sulphides) we obtained a true isochron (MSWD = 0.63) age of 2578.3 +/- 0.9 Ma, which is identical to and more precise than a recently published U-Pb zircon age (2579 3 Ma) for a Great Dyke websterite [Earth Planet. Sci. Lett. 180 (2000) 1-12]. Reproducibility of this age by means of an isochron we regard as a robust test of accuracy over a wide dynamic range. We show that reliable and accurate Pb-isotope data can be obtained by careful operation of second-generation MC-ICP magnetic sector mass spectrometers. (C) 2002 Elsevier Science B.V. All rights reserved.

Flavivirus isolations from mosquitoes collected from western Cape York Peninsula, Australia, 1999-2000

After the 1st appearance of Japanese encephalitis virus (JE) on mainland Australia in 1998, a study was undertaken to investigate whether JE had become established in enzootic transmission cycles on western Cape York Peninsula. Adult mosquitoes were collected during the late wet season from Kowanyama and Pormpuraaw in April 1999, and Pormpuraaw and Barr's Yard in April 2000. Despite processing 269,270 mosquitoes for virus isolation, no isolates of JE were obtained. However, other flaviviruses comprising Murray Valley encephalitis virus, Kunjin virus, Alfuy virus, and Kokobera virus (KOK) were isolated. Isolates of the alphaviruses Ross River virus, Barmah Forest virus (BF), and Sindbis virus (SIN) also were obtained. The majority (88%) of isolates were from members of the Culex sitiens subgroup. Single isolates of KOK, BF and SIN were obtained from Ochlerotatus vigilax, Oc. normanensis, and Anopheles bancroftii, respectively. The isolations of flaviviruses during the late wet season indicate that conditions were suitable for flavivirus activity in the area. No evidence was found to suggest that JE has become established in enzootic transmission cycles on western Cape York, although study sites and field trips were limited.

Nitrate ammonification and its relationship to the accumulation of ammonium in a Vertisol subsoil

High concentrations of ammonium ( up to 270 kg N/ha) have been observed in a Vertisol soil below 1 m depth near Warra in south-east Queensland. This study examined the possibility that increased water movement into the subsoil after the removal of native vegetation, and a subsequent increase in periods of waterlogging, could have triggered nitrate ammonification and be responsible for the production of ammonium. Two incubation experiments were conducted to test this hypothesis. The first involved the incubation of repacked cores that had been amended with 30 mg N/kg of 5 atom% N-15 nitrate under low oxygen conditions for a period of 360 days. Over this time period the N-15 enrichment of the exchangeable ammonium fraction was monitored in order to detect any reduction of nitrate to ammonium. The second experiment involved the incubation of soil amended with 30 mg N/ kg of 5 atom% N-15 nitrate under waterlogged and low oxygen conditions for 75 days. During this period the redox potential of the soil was monitored using a field test to determine if reducing conditions would develop in this soil over a period of waterlogging, combined with the monitoring of any nitrate reduction to ammonium. The results of these experiments indicated that a small amount of nitrate ammonification (< 0.1 mg N/ kg) could be observed in the Warra subsoil, but that unless the rate of reduction were to significantly increase with time, this could not account for the accumulation of ammonium observed in the field. The environmental conditions that would make either dissimilatory or abiotic nitrate ammonification favourable were not observed to develop. Consequently, it has been concluded that the observed nitrate ammonification occurred via an assimilatory pathway. Due to the low rate of microbial activity in this subsoil it is considered unlikely that this process was responsible for the subsoil ammonium accumulation at Warra.

Subsoil nitrogen mineralisation and its potential to contribute to NH4 accumulation in a Vertosol

High concentrations of NH4+ (up to 270 kg N/ha) have been observed in a Vertosol below 1 m depth in south-east Queensland. This study examined the possibility that mineralisation associated with the removal of native vegetation (Acacia harpophylla) for cropping was responsible for the production of NH4+. Particularly, the potential contribution of decomposing root material and/or dissolved organic nitrogen (DON) leached into the subsoil after clearing was investigated. The amount of N that was contained within native vegetation root material was determined from an area of native vegetation adjacent to the cleared site containing elevated NH4+ concentrations. In addition, the amount of NH4+ that could be mineralised in the native vegetation soil was determined by monitoring NH4+ concentrations over 360 days in intact cores, and by conducting waterlogged incubations. To determine the rate at which a source of DON leached into the subsoil would mineralise, soil was amended with glutamic acid at a rate of 250 mg N/kg and placed under waterlogged incubation. The possibility that the acidic pH of the subsoil, or the lack of a significant subsoil microbial population, was inhibiting mineralisation was also examined by increasing soil pH from 4.4 to 7.0, and inoculating the subsoil with surface soil microorganisms during waterlogged incubations. Low concentrations of N, approximately 90 kg N/ha between 1.2 and 3 m, were found in the native vegetation root material. In addition, no net N mineralisation was observed in either the extended incubation of intact cores or in the control samples of the waterlogged incubations. Net N mineralisation was also not detected when the subsoil was amended with a source of organic N. Results indicate that this lack of mineralisation is largely due to pH inhibition of the microbial population. It is concluded that the mineralisation of either in situ organic material, or DON transported to the subsoil during leaching events, is unlikely to have significantly contributed to the subsoil NH4 accumulation at the study site.

Sistema Nacional de Informa????es de Defesa do Consumidor (Sindec)

O Sistema Nacional de Informa????es de Defesa do Consumidor integra Procons de 23 estados brasileiros e do Distrito Federal. ?? um sistema que permite o registro de demandas individuais de consumidores, bem como a gest??o dos procedimentos que tratam essas demandas. O Sindec consolida os registros em bases locais e forma um banco nacional de informa????es sobre problemas enfrentados por consumidores. Essas informa????es podem ser consultadas por consumidores, pelos Procons integrados e por toda a sociedade, por meio do s??tio www.mj.gov.br/sindec. O Sindec re??ne informa????es de mais de 80 Procons (entre estaduais, municipais e do Distrito Federal), est?? presente em mais de 110 cidades de todas as regi??es brasileiras e consolida registros de demandas de mais de 2 milh??es de consumidores contra mais de 10 mil fornecedores

A????es premiadas no 6?? Concurso de Inova????es na Gest??o P??blica Federal

Projetos premiados no 6?? Concurso de Inova????es na Gest??o P??blica Federal - Pr??mio Helio Beltr??o. Representam contribui????es para a melhoria da gest??o p??blica nas seguintes ??reas: planejamento e gest??o estrat??gica, articula????o de parcerias, atendimento ao usu??rio, gerenciamento de informa????es, gest??o financeira e or??ament??ria, gest??o de pessoas e capacita????o, gest??o de servi??os gerais, gest??o de suprimentos e simplifica????o e agiliza????o de procedimentos

Voluntariado e cidadania

O Projeto Corporativo de voluntariado empresarial nos Correios catalisa todas as iniciativas de solidariedade originadas na empresa. Tem como foco de atua????o a inclus??o social e ?? operacionalizado por meio de comit??s constitu??dos por colaborares, familiares e aposentados da empresa, obedecendo a uma programa????o elaborada com institui????es filantr??picas ou comunidades. Atua nos segmentos de seguran??a alimentar, educa????o, inclus??o digital, sa??de, cultura, cidadania, gera????o de trabalho e renda, meio ambiente, esporte, habita????o, desenvolvimento rural e parcerias solid??rias. Em 2002, as a????es contemplaram 119 institui????es filantr??picas e comunidades, em 71 munic??pios de diferentes unidades da Federa????o. Mais de 7.500 pessoas, entre colaboradores, familiares e aposentados, beneficiaram diretamente cerca de 20 mil pessoas

Sistema de tratamento de parcelamento: tratapar

O sistema de Trata Parcelamentos - TRATAPAR tem como objetivo realizar procedimentos operacionais para constitui????o de processos de parcelamentos para contribuintes com d??vidas na Secretaria da Receita Federal, mediante a integra????o entre os muitos sistemas de cobran??a existentes, possibilitando, de forma autom??tica, o cadastramento dos processos, a recupera????o e a suspens??o dos cr??ditos tribut??rios. A proposta do sistema ?? a redu????o do trabalho necess??rio para a constitui????o dos processos de parcelamentos, de forma automatizada, e como apoio na negocia????o entre os representantes da Secretaria da Receita Federal e os contribuintes interessados em parcelar e solucionar suas d??vidas

A consolida????o institucional do cargo de dirigente p??blico

O trabalho pretende desenvolver uma reflex??o sobre a profissionaliza????o dos cargos de dire????o na administra????o p??blica e sua evolu????o ao longo das ??ltimas d??cadas nos pa??ses desenvolvidos, tendo como eixo condutor a institucionaliza????o dos cargos de dirigentes p??blicos nos sistemas pol??tico-administrativos contempor??neos. Inicia-se definindo a expans??o e o desenvolvimento do gerenciamento nos sistemas p??blicos, descrevendo, de forma breve e comparada, sua evolu????o mais recente em alguns pa??ses da OCDE. Em seguida, s??o apontados os tra??os b??sicos de um modelo de exerc??cio das fun????es de dire????o na administra????o p??blica. A seguir, trata-se do tema central mencionado. Primeiramente, o texto define os elementos que configuram um marco institucional para as fun????es de dire????o no setor p??blico. Depois, aborda o conte??do, o alcance e o ??mbito das reformas necess??rias para a constru????o desse marco. Por ??ltimo, analisa as vari??veis que podem influenciar a elabora????o das reformas, expondo os principais desafios e dificuldades tra??ados pelos empenhos de reforma.

Levantamento te??rico sobre as causas dos insucessos das tentativas de reforma administrativa

O presente artigo tem como objetivo identificar e analisar os principais motivos apontados na literatura pertinente como causadores dos sucessivos e reiterados fracassos das tentativas de reforma da administra????o p??blica brasileira. As referidas tentativas foram empreendidas em 1938, quando da cria????o do Departamento Administrativo do Servi??o P??blico (DASP), durante a ditadura do Estado Novo; em 1963, quando Ernani do Amaral Peixoto foi designado ministro extraordin??rio para a Reforma Administrativa; em 1967, quando da edi????o do Decreto-Lei n?? 200, de 25/2/1967 e, tamb??m, em 1986, 1990 e 1995, nos Governos Sarney, Collor e Cardoso, respectivamente. Todas elas visavam, basicamente, a implantar a meritocracia na administra????o p??blica brasileira. Segundo os autores consultados, essas tentativas foram malsucedidas devido aos seguintes fatores: a quest??o da depend??ncia da trajet??ria, as caracter??sticas das organiza????es que dificultam a ocorr??ncia de altera????es institucionais, os elementos de natureza sociol??gica, o fato de a reforma administrativa ser bem p??blico sujeito a problemas de a????o coletiva e, finalmente, as peculiaridades do sistema pol??tico brasileiro.

A sociologia de Max Weber: sua import??ncia para a teoria e a pr??tica da administra????o

A tradu????o integral da obra de Max Weber ??? Wirtschaft und Gesellschaft ??? empreendida pela editora mexicana ??? Fondo de Cultura Econ??mica, sob a esclarecida dire????o de Jos?? Medina Echavarr??a, ?? um acontecimento a cuja magnitude esta Revista n??o pode permanecer indiferente. ?? esta a primeira vez que a referida obra aparece em l??ngua diferente da original, pois a anunciada tradu????o do seu primeiro volume, realizada por Parsons-Henderson, n??o foi editada at?? o presente e, ao que me consta, circula mimeografada, em restritos centros de estudo dos Estados Unidos. Apesar de inacabada e fragment??ria e de ser um livro p??stumo, publicado gra??as ?? dedica????o e compet??ncia de Marianna Weber, esposa do autor, Economia e Sociedade ?? a obra n??o s?? onde se re??nem os temas centrais de Max Weber, como tamb??m onde ele exp??e o seu sistema de sociologia.

Escolas de governo europ??ias reformam o ensino e voltam-se ?? Europa

As principais escolas nacionais de governo da Europa encontram-se hoje em processo de transforma????o. Nas agendas de mudan??a, ressaltam-se a ???europeiza????o??? da forma????o e o refor??o no ensino de lideran??a. ?? o caso da ENA ??? Ecole Nationale d???Administration, que oferece cursos de forma????o inicial e continuada aos servidores que comp??em a chamada ???alta fun????o p??blica??? da Fran??a. As cr??ticas lan??adas ?? tradicional escola ??? ???francesa, parisiense, tecnocr??tica e elitista demais??? ??? tiveram impacto no resultado da reforma. Um ter??o do per??odo de forma????o inicial passou a ser dedicado ao estudo da Europa, o campus foi transferido de Paris a Strasbourg, a forma????o te??rica ?? hoje alternada com a realiza????o de est??gios e os concursos passaram a ser abertos a um p??blico n??o apenas puramente acad??mico.

Aprender a governar: a aprendizagem de funcion??rios p??blicos para as carreiras de estado

Esta tese investiga como dois grupos de funcion??rios p??blicos seleciona dos para as carreiras de Estado no Brasil aprendem a desempenhar as suas fun????es. Deste m odo, busca compreender os processos de aprendizagem, formais e informais, da e ntrada desses servidores p??blicos como alunos nos espa??os destinados ?? sua forma????o, at?? sua inser ????o nos espa??os de trabalho, como aprendizes. A pesquisa justifica-se porque, sendo as am ostras estudadas consideradas boas refer??ncias no servi??o p??blico, faz-se necess??ri o compreender como se d?? a aprendizagem para o exerc??cio dessas carreiras de Estado. Quatro dimens??es s??o consideradas para investigar a aprendizagem dos funcion??rios p??blicos: primeira, o surgimento e evolu????o da forma????o em administra????o p??bli ca no Pa??s. Segunda, as escolas de governo, lugares prop??cios ?? aprendizagem, influente s para a administra????o p??blica do Pa??s, inclinados ?? discuss??o de novas solu????es e cr??ticos na identifica????o, an??lise e apropria????o das experi??ncias verificadas em outras realidades. Te rceira, os cursos de forma????o inicial, espa??os para o primeiro contato com a fun????o escol hida e os seus desafios, saberes necess??rios e ferramentas dispon??veis. Quarta, a inse r????o no ambiente de trabalho, decisiva para o processo de aprendizagem social dos funcion??rios novatos por interm??dio das comunidades de pr??tica.

Efeito da geometria dos dentes da serra de fita na produção de madeira serrada de eucalipto

O objetivo deste trabalho foi determinar o efeito dos parâmetros que compõem os dentes de serra de fita na produção e qualidade da madeira serrada de eucalipto. Analisou-se o efeito de dois passos de dentes (57,15 mm e passo variado: 50,8 - 50,8 - 50,39 - 50,71 - 60,03 - 60,35 mm), de dois ângulos de ataque (26 e 270) e de duas alturas (22 e 25,4 mm) em duas classes diamétricas (25 a 34 cm e 35 e 47 cm) de clones de híbridos Eucalyptus grandis x Eucalyptus urophylla com 15 anos de idade. Não houve ganho de qualidade quando se trabalhou com passo variado. As lâminas de serra que possuíam ângulo de ataque de 270 e passo único tanto com altura do dente de 22 mm quanto com 25,4 mm geraram desvios acima da espessura-meta. A menor variação em torno da espessura-meta foi obtida quando se utilizaram lâminas de serra de ângulo de ataque de 270 e altura do dente de 25,4 mm. O maior desvio ocorreu quando o desdobro foi efetuado com passo variado e ângulo de ataque de 260. A utilização de passo variado, de modo geral, foi o que apresentou maiores desvios na espessura das tábuas em relação à espessura desejada.