8,645 research outputs found
Lithogeochemical halos and geochemical vectors to stratiform sediment hosted Zn-Pb-Ag deposits. Part 2: HYC Deposit, McArthur River, Northern Territory
No full textThe giant stratiform Zn-Pb-Ag HYC deposit displays a broad Zn, Pb and Tl halo which extends laterally along the favourable pyritic black shale facies of the Barney Creek Formation for at least 15 km west of the deposit. A ferroan dolomite/ankerite halo overlaps with the Zn-Pb-Tl halo extending up to 250 m into the immediate stratigraphic hangingwall, and 50 to 100 m into the footwall sediments close to the deposit. A manganese carbonate halo is offset from the ferroan dolomite/ankerite halo, being concentrated in the immediate footwall of the deposit and extending laterally along the W-Fold Shale Member. Manganiferous carbonate forms the most pronounced and laterally extensive halo at HYC extending well beyond the Zn-Pb-Tl and ankerite halos. The geometry and extent of the halos described above are based on sampling and analyses from two drill holes reported in this study and a further six drill holes reported previously by I.B. Lambert and K.M. Scott [J. Geochem. Explor. 2, 307-330, 1973]. The SEDEX alteration index previously proposed as a vector for the Lady Loretta deposit [R.R. Large and P.J. McGoldrick, 1998, J. Geochem. Explor. 63, 37-56] has been shown to have applications in the McArthur Basin for defining the favourable stratigraphic unit hosting stratiform Zn-Pb-Ag mineralisation. A modified alteration index (AI Mark 3) has also been developed which eliminates the effect of the shale/dolomite ratio on the index and thus highlights the control of carbonate chemistry and its relationship to stratiform mineralisation. The application of a group of indices including Zn, Pb, Tl, SEDEX alteration index, AI Mark 3 and manganese content of dolomite (MnO(d)) is proposed for defining the most favourable stratigraphic units for stratiform Zn-Pb-Ag mineralisation within carbonate-bearing sedimentary basins. (C) 2000 Elsevier Science B.V. All rights reserved. | The giant stratiform Zn-Pb-Ag HYC deposit displays a broad Zn, Pb and Tl halo which extends laterally along the favourable pyritic black shale facies of the Barney Creek Formation for at least 15 km west of the deposit. A ferroan dolomite/ankerite halo overlaps with the Zn-Pb-Tl halo extending up to 250 m into the immediate stratigraphic hangingwall, and 50 to 100 m into the footwall sediments close to the deposit. A manganese carbonate halo is offset from the ferroan dolomite/ankerite halo, being concentrated in the immediate footwall of the deposit and extending laterally along the W-Fold Shale Member. Manganiferous carbonate forms the most pronounced and laterally extensive halo at HYC extending well beyond the Zn-Pb-Tl and ankerite halos. The geometry and extent of the halos described above are based on sampling and analyses from two drill holes reported in this study and a further six drill holes reported previously by I.B. Lambert and K.M. Scott. The SEDEX alteration index previously proposed as a vector for the Lady Loretta deposit has been shown to have applications in the McArthur Basin for defining the favourable stratigraphic unit hosting stratiform Zn-Pb-Ag mineralization. A modified alteration index (AI Mark 3) has also been developed which eliminates the effect of the shale/dolomite ratio on the index and thus highlights the control of carbonate chemistry and its relationship to stratiform mineralization. The application of a group of indices including Zn, Pb, Tl, SEDEX alteration index, AI Mark 3 and manganese content of dolomite (MnOd) is proposed for defining the most favourable stratigraphic units for stratiform Zn-Pb-Ag mineralization within carbonate-bearing sedimentary basins
Tradiciones populares de Venezuela y sus raices Ibericas [Popular traditions of Venezuela and its Iberian roots]
No full textEstimating demographic parameters for capture-recapture data in the presence of multiple mark types
No full textIn mark-recapture studies, various techniques can be used to uniquely identify individual animals, such as ringing, tagging or photo-identification using natural markings. In some long-term studies more than one type of marking procedure may be implemented during the study period. In these circumstances, ignoring the different mark types can produce biased survival estimates since the assumption that the different mark types are equally catchable (homogeneous capture probability across mark types) may be incorrect.We implement an integrated approach where we simultaneously analyse data obtained using three different marking techniques, assuming that animals can be cross-classified across the different mark types. We discriminate between competing models using the AIC statistic. This technique also allows us to estimate both relative mark-loss probabilities and relative recapture efficiency rates for the different marking methods.We initially perform a simulation study to explore the different biases that can be introduced if we assume a homogeneous recapture probability over mark type, before applying the method to a real dataset. We make use of data obtained from an intensive long-term observational study of UK female grey seals (Halichoerus grypus) at a single breeding colony, where three different methods are used to identify individuals within a single study: branding, tagging and photo-identification based on seal coat pattern or pelage.Peer reviewe
Terminal suturing of Gondwana along the southern margin of South China Craton : evidence from detrital zircon U-Pb ages and Hf isotopes in Cambrian and Ordovician strata, Hainan Island
No full textThis work was supported by the National Natural Science Foundation of China (grants 41472086 and 41272120), “111” Project (B08030), the fundamental Research Funds for the Central Universities, China University of Geosciences (Wuhan) (CUG2012019240 and CUG2013019137). The first author also acknowledges China Scholarship Council (grant 201208420001) for supporting his research in the University of St. Andrews. Date of Acceptance: 20/11/2014Hainan Island, located near the southern end of mainland South China, consists of the Qiongzhong Block to the north and the Sanya Block to the south. In the Cambrian, these blocks were separated by an intervening ocean. U-Pb ages and Hf isotope compositions of detrital zircons from the Cambrian succession in the Sanya Block suggest that the unit contains detritus derived from late Paleoproterozoic and Mesoproterozoic units along the western margin of the West Australia Craton (e.g., Northampton Complex) or the Albany-Fraser-Wilkes orogen, which separates the West Australia and Mawson cratons. Thus, in the Cambrian the Sanya Block was not part of the South China Craton but rather part of the West Australian Craton and its environs. In contrast, overlying Late Ordovician strata display evidence for input of detritus from the Qiongzhong Block, which constituted part of the southeastern convergent plate margin of the South China Craton in the early Paleozoic. The evolving provenance record of the Cambrian and Ordovician strata suggests that the juxtaposition of South China and West Australian cratons occurred during the early to mid-Ordovician. The event was linked with the northern continuation of Kuungan Orogeny, with South China providing a record of final assembly of Gondwana.Peer reviewe
O processo de verticalização e seus problemas no bairro de Manaíra, João Pessoa-PB.
No full textThe work traces the verticalization process in District Manaíra in João Pessoa-PB. To fulfill its purpose broke the concept, causes, and consequences of this process mainly the problems caused by such a process. Reports related to the process of urban verticalization in order to understand the process and support research studies. "Was taken as a base study dissertation titled The study Manaíra neighborhood in João Pessoa, Paraíba," Nobrega (2011). Additionally, consultation to planning legislation relating to the theme. Research upgraded the empirical survey and mapping by the cited author. Thus, in addition to consulting government institutions such as the Water and Sewerage Company of Paraíba, the core of the research corresponds to the empirical survey of land use studied in the neighborhood that was recorded by consignment types of buildings. This survey maps of land use were developed. Finally, the article discusses the problems caused by the process of verticalization in District Manaíra located on the edge of João Pessoa-PB.O trabalho traça um panorama do processo de verticalização, no Bairro de Manaíra na cidade de João Pessoa-PB. Para cumprir seu propósito partiu-se do conceito, causas, consequências resultantes deste processo e principalmente, os problemas ocasionados por tal processo. Reporta-se a estudos relacionados ao processo de verticalização urbana, no intuito de compreender o processo e fundamentar a pesquisa. “Tomou-se como estudo base a dissertação de mestrado intitulada O estudo do bairro de Manaíra em João Pessoa, Paraíba”, de Nóbrega (2011). Além disso, consulta-se a legislação urbanística referente à temática. A pesquisa atualizou o levantamento empírico e o mapeamento realizado pela autora citada. Desta forma, além da consulta as instituições governamentais como a Companhia de Águas e Esgotos da Paraíba, IBGE, Corpo de Bombeiros e etc., o cerne da pesquisa corresponde ao levantamento empírico do uso do solo do bairro estudado em que se registrou lote por lote o tipo de edificação. Deste levantamento foram elaborados mapas do uso do solo. Por fim, foram identificados e abordados os problemas ocasionados pelo processo de verticalização no Bairro de Manaíra localizado na orla de João Pessoa-PB
Spatio-temporal evolution of the West African monsoon during the last deglaciation
No full textOn the basis of a multi-proxy data set from the Gulf of Guinea (eastern equatorial Atlantic) we reconstruct the spatio-temporal evolution of the West African monsoon (WAM) and present evidence for a decoupling between latitudinal shifts of the rain belt and WAM intensification. The onset of deglacial monsoon invigoration at ∼16,600 years before present lagged northward migration of a weak rainfall zone by ∼2800 years. Conversely, during the Younger Dryas (YD) time interval, WAM precipitation was severely reduced but we find no evidence for a large-scale retreat of the rainfall front. This observation is not in agreement with the hypothesis of a large-scale shift of the intertropical convergence zone south of the tropical WAM region during the YD. Our results can be better reconciled with the newly emerging concept of a strong influence of Tropical Easterly and African Easterly Jets on modern WAM
Vector boson production in p+Pb and Pb+Pb collisions measured with ATLAS at the LHC
No full textElectroweak boson production processes (W, Z and photon) provide access to the earliest moments of heavy ion collisions. Furthermore, because they do not undergo strong interactions, they are sensitive to the initial-state geometry of the collision and potentially the details of the nuclear parton distribution functions (PDF). ATLAS results on vector boson yields have demonstrated binary collision scaling in Pb+Pb collisions. In p+Pb collisions, the measurement of vector bosons provides possible constraints on the nuclear PDF and insights into the details of the initial collision geometry. We report on the latest results of vector boson production in p+Pb collisions at sqrt(sNN)=5.02 TeV and Pb+Pb collisions at sqrt(sNN)=2.76 TeV. In p+Pb collisions, production yields and lepton charge asymmetry of W bosons are presented as a function of pseudorapidity of the charged lepton and centrality. Photon and Z yields are presented differentially as a function of transverse momentum, rapidity and centrality. The vector boson yields are compared to calculations incorporating different PDF sets, as well as different centrality calculations
Mark Meerovich and SMD Methodology
No full textThe article presents Alexander Rappaport's comments on the article “Mark Meerovich’s System-Based Methodological Approach to the History of Architecture and Town-Planning” written by E. Bagina
Gene expression of Ntann12 in Nicotiana tabacum to Pb treatment
No full textPlants are sessile organisms that are unable to move away from adverse environmental conditions. In order to survive or adapt their growth to environmental stresses, plants undergo physiological, biochemical and molecular changes. Lead (Pb), on the other hand, is a widespread heavy metal pollutant that is commonly found in the environment. It is highly persistent and causes toxicity to plants, animals, and human. To advance our understanding in Pb tolerance in plants and subsequently develop phytoremediation technology, there is a need to identify genes associated with Pb stress.
Nicotiana tabacum has the characteristics of a plant ideal for phytoremediation. It has deep and highly branched root system, is tolerant to Pb pollutant, and repulsive to herbivores. Recent studies have shown that annexins participate in abiotic stress responses. Ntann12 is an annexin in Nicotiana tabacum. It was found to be upregulated upon Rhodoccocus fascians infection, salt and abscisic acid treatments. It is likely that Ntann12 could be involved in the response of plants to Pb stress and play a role to defend plants against Pb-induced oxidative damage
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