1,722,242 research outputs found
Age and palaeoenvironmental constraints on the genesis of the Yandi channel iron deposits, Marillana Formation, Pilbara, northwestern Australia
No full textFossil pollen and spores preserved in organic-rich claystones near the base of the palaeochannel hosting the Tertiary Yandi channel iron deposits (CID) provide an in situ constraint on the age of this world-class orebody. This assemblage also aids understanding of the palaeoenvironment leading to the deposition and preservation of the host Marillana Formation. The provisional Early Oligocene age of claystones links the genesis of the Yandi CID to the profound disruption of global climates and oceanography at the Eocene-Oligocene transition (Terminal Eocene Event) and provides circumstantial evidence that ore formation was linked to the development of a warm south-flowing proto-Leeuwin Current along the Pilbara coast. It is likely that rainfall increased but remained strongly seasonal (monsoonal?) as global climates wormed during the Late Oligocene - Early Miocene. The same fossil evidence indicates that wood fragments, the iron-oxide-replaced remains of which are a significant component of cemented goethitic gravel making up CID, came from Casuarinaceae- and Myrtaceae-dominated sclerophyll communities lining the channel banks. Increasingly dry conditions since the late Early Miocene Climatic Optimum are likely to have contributed to the preservation of CID at Yandi
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Perencanaan keuangan bapak Yandi pada Tabungan Mandiri, Deposito BCA, Asuransi Manulife, Reksadana PNM Puas, Optima Obligasi, Trim Dana Stabil, Danamas Stabil, Bahana Infrastruktur, Fortis Pesona, Schroder Dana Prestasi, dan Schroder Dana Prestasi Plus
No full textTugas akhir ini membahas perencanaan keuangan bagi Bapak Yandi dengan tujuan untuk membantu dalam memenuhi tujuan-tujuan keuangan yang diinginkan olehnya. Tujuan keuangan tersebut antara lain adalah kebutuhan dana darurat, asuransi, dana pendidikan, dana pensiun, dana pembelian rumah, dana pembelian mobil, dan dana liburan. Untuk dana darurat digunakan produk Tabungan Bank Mandiri, Deposito Bank Central Asia, dan Reksa Dana PNM Puas. Untuk dana tabungan lainnya diinvestasikan di Reksa Dana Optima Obligasi, Trim Dana Stabil, Danamas Stabil, Bahana Dana Infrastruktur, Fortis Pesona, Schroder Dana Terpadu, dan Schroder Dana Prestasi Plus. Sedangkan kebutuhan asuransi jiwa dan kesehatan Bapak Yandi dipilih asuransi Manulife Financial. Dengan memiliki arus kas yang positif dan adanya aset yang cukup, membuat Bapak Yandi dapat mencapai tujuan keuangannya
Simulation of correlated variables: a comparison of approaches with a case study from the Yandi Channel iron deposit.
Get PDFConditional Simulation of correlated assay variables is a subject of significant recent and current development. The objective of this thesis is to evaluate the available approaches in this area for mining applications. BHP Billiton’s (BHPB) Yandi Channel Iron Deposit (Yandi CID) in Western Australia was selected for these tests.
The Yandi CID is 150 km by road North of the town of Newman in the Pilbara region. This channel iron deposit (CID) infills the meandering tertiary palaeochannels of Marillana Creek, which are 450m - 750m wide and approximately 100m deep in the centre. The deposits outcrop as a series of low mesas beside the present day creeks and were divided into three areas (Western, Central and Eastern) within which individual mesas are numbered. A North-South trending part of the channel (mesas C4, and part of C5) is the focus of this study. Drilling of the C4 and C5 mesas is on grids varying from 25m x 50m to 100m x 100m.
Although the Yandi CID is mined for iron ore, the concentrations of the contaminants Al₂O₃, SiO₂ and P₂O₅ are economically critical. The loss on ignition (LOI), while not strictly speaking a contaminant, is also an important product characteristic for iron ore customers. The correlations between the assay variables and their relative abundances vary from sample to sample. For resource modelling, individual samples were grouped together into domains of similar geological and geochemical character. The ‘Main Ore Zone’ of the Yandi CID was the domain selected for study in this thesis. Detailed univariate, bivariate and multivariate analyses were used to characterise this domain before proceeding to the simulation study.
The Conditional Simulation methods evaluated in this thesis are all Gaussian-based and they include Conditional Co-Simulation using the Linear Model of Co-Regionalisation and two other, alternative multivariate simulation methods, which use Min/Max Autocorrelation Factors or the Stepwise Conditional Transform to de-correlate assay variables before performing independent Conditional Simulation. Twenty simulations were generated for each of these simulation methods. It was found that Conditional Co-Simulation best reproduced the characteristics (histograms, variogram, scatterplots etc) of the declustered drill hole data. Whilst simulation using Min/Max Autocorrelation Factors generally produced acceptable results, the method did not adequately reproduce the variance of the assay variables. The univariate statistics, histograms and experimental variograms were acceptable for simulations generated from the Stepwise Conditional Transform. Bivariate statistics, cross-variograms and scatterplot reproduction for the Stepwise Conditional Transform were unacceptable. This method produced inferior results because there were insufficient samples to obtain a reliable transform of the third assay variable in the transformation sequence.
None of the abovementioned simulation methods provides good reproduction of all the scatterplots. This is due to the presence of clay pods, which cause some scatterplots to display two trends. These clay pods contain higher percentages of SiO₂ and Al₂O₃ than the surrounding material (known as CID). The clay pods are generally smaller than the drill-grid dimensions and thus their locations are generally unknown. The locations of the clay pods were simulated via Indicator Conditional Simulation. Condition Co-Simulation was then performed separately for the clay pods and the CID. This significantly improved the reproduction of the correlation coefficients, the scatterplots and visually the simulation was more geologically realistic. This Indicator Conditional Simulation of clay pods followed by Conditional Co-Simulation of assay variables is the recommended approach for simulation at the Yandi CID.Thesis (M.Sc.) - University of Adelaide, School of Mathematical Sciences, 201
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
- …
