Many interactions drive the adsorption of molecules on surfaces, all of which can result in a measurable change in surface stress. This article compares the contributions of various possible interactions to the overall induced surface stress for cantilever-based sensing applications. The surface stress resulting from adsorption-induced changes in the electronic density of the underlying surface is up to 2-4 orders of magnitude larger than that resulting from intermolecular electrostatic or Lennard-Jones interactions. We reveal that the surface stress associated with the formation of high quality alkanethiol self-assembled monolayers on gold surfaces is independent of the molecular chain length, supporting our theoretical findings. This provides a foundation for the development of new strategies for increasing the sensitivity of cantilever-based sensors for various applications.

The Ravenswood vein array/stockwork deposits (total endowment ~ 4Moz @ 1.6g/t), and the nearby Mt Wright breccia-hosted deposit (total resource ~ 1Moz @ 3.3g/t), are both Permo-Carboniferous intrusion related systems, located in North Queensland, Australia. The Ravenswood system includes both the recently exhausted large tonnage Sarsfield-Nolans deposit and the historic, smaller, higher grade Buck Reef West-Sunset mines. Gold mineralisation in both areas is associated with quartz and sulphides developed within altered Paleozoic intrusive rocks of the Ravenswood Batholith. Analysis of ore stage fluid inclusions from the three deposits indicate distinct temperatures for ore deposition, mostly between 200 and 300° at Buck Reef West, from 300 to 400°C at Sarsfield and about 400 to 550°C at Mt Wright. Salinities for the fluid inclusions from the different deposits are similar and mostly between 8 and 12 wt% NaCl equivalent. The δ34S of sulphides indicate that the sulphur in the ore fluids had a variable composition with higher δ34S at geologically distinct Mt Wright compared to the Ravenswood veins. Collectively, stable isotopes data are consistent with a predominantly magmatic source for the ore forming fluids at the Ravenswood deposits, although there is also evidence of involvement of surface waters in the mineralizing systems at Sarsfield and Buck Reef West.

Primary colloforrn textures preserved in ore deposits can be a useful tool in understanding changing conditions of ore formation due to the sequential development of the colloforrn layers. However, the growth controls that influence formation of these textures are poorly understood. To try to address this problem, samples from two ore deposits, Greens Creek in Alaska and Ezuri in Japan, have been systematically analyzed for grain size and shape, crystal preferred orientation (CPO), sulfur isotope composition, and trace element content. Grain size and shape varies between layers of equant, similar to 20 mu m crystals to acicular and elongate crystals up to several millimeters in length. Electron backscatter diffraction (EBSD) reveals that both samples have an initial random orientation of crystals with CPO in subsequent layers developed either about < 100 >, < 110 >, or < 111 > crystallographic axes. Despite similarity in texture, the sulfur isotope results from Greens Creek colloforms have a very negative, open-system bacteriogenic delta S-34 between -40 and -32 parts per thousand, whereas the Ezuri colloform has a positive delta S-34 of similar to+5 parts per thousand, typical of hydrothermal sulfur in Kuroko ores. Trace element results indicate variability in As, Sb, and Cu distribution. Whereas trace element variability at Greens Creek appears to be related to changes in delta S-34, with a heavier signature correlating with sequestration of Sb in outer layers, overall the detailed analyses reveal that in both Greens Creek and Ezuri, there is no systematic correlation between sulfur source or trace element sequestration and CPO. This suggests that the abrupt changes in CPO recorded appear most likely to be influenced by changes in degree of supersaturation.

Most research on human decidual leucocytes to date has focused on the predominant CD56+ uterine natural killer (uNK) cell population in early pregnancy. Few reports have documented decidual leucocyte populations after 13 weeks gestation and in late pregnancy. Placental bed (decidua basalis) and non-placental bed (decidua parietalis) biopsies from normal pregnancies were taken from women undergoing termination of pregnancy in the 1st and 2nd trimesters and following Caesarean section in the 3rd trimester. Immunohistochemistry was used to quantify the numbers of decidual cells expressing CD56, CD3, CD8, CD94, NKG2A and CD14 and double labelled CD161+CD3+ NKT-like cells. Although a significant reduction in CD56+ uNK cells was found in 3rd trimester samples compared with 1st and 2nd trimester decidua, a substantial residual CD56+ leucocyte population was identified in 3rd trimester decidua. Expression of the KIR CD94/NKG2A mirrored that of CD56 at all gestational ages, providing an explanation for the absence of cytotoxic responses at the fetal-maternal interface. There was no difference in leucocyte populations between decidua basalis and decidua parietalis. Double immunohistochemical labelling revealed small numbers of decidual CD3+CD56+ and CD8+CD56+ cells, which decreased in number at term, and CD161+CD3+ cells, which increased in number at term. No differences in leucocyte populations were detected between decidua parietalis and decidua basalis. In contrast to previous reports, a substantial residual CD56+ cell population was demonstrated in 3rd trimester decidua. Decidual cytotoxic T-lymphocytes did not alter in number during gestation, while in contrast CD14+ macrophages decreased at term, representing the smallest decidual population assessed.

Colloform textures have been described from many of the world's sulphide ore deposits and involve formation of distinct microcrystalline layers. These textures provide information related to sequential stages of ore formation, yet their mechanism of growth is poorly understood. This study has analysed a series of colloform samples from the Galmoy Zn + Pb mine, Ireland. Results indicate that the growth sequence is not always intuitive and layers that appear stratigraphic upon cursory observation may no be. The crystal preferred orientation (CPO) of discrete colloform layers abruptly switches between different orientation axes. Examination of the same layers using in situ laser sulphur isotope analysis reveals equally striking changes in delta S-34 signature between end-member bacteriogenic (-25%) and hydrothermal (+10%) sources. Although these results, combined with petrographic observation, allow the determination of a probable growth history. there is no correlation between shifting CPO and delta S-34 signature. Trace element analysis reveals changes in trace element sequestration between colloform layers. Cadmium- and chlorine-rich layers correspond to a hydrothermal sulphur source, whereas iron-rich layers correspond to a bacteriogenic sulphur source. In the absence of alternative mechanisms we suggest that the most likely factors influencing CPO changes are temperature and degree of supersaturation during two-fluid mixing.

Nicholas Perrin in his 2002 monograph, Thomas and Tatian: The Relationship between the Gospel of Thomas and the Diatessaron, and in a series of subsequent publications has proposed that, if one translates it back into Syriac, a series of 502 catchwords can be found to run through the Gospel of Thomas. According to Perrin this number is greater than the number of catchwords in Coptic (269) or in Greek (263) and demonstrates that the Gospel of Thomas was originally composed in Syriac, which in turn makes it likely that the Gospel of Thomas was written with a knowledge of Tatian's Diatessaron. Here, a sample of Perrin's alleged catchwords is investigated and is found implausible. Consequently his late dating of the Gospel of Thomas cannot be established.

Fluid inclusions in late-Isan quartz veins associated with regional Na-Ca alteration (albitisation), in the Mary Kathleen Fold Belt and the Cloncurry District of the Eastern Mt Isa Block, have been analysed for naturally occurring and neutron produced isotopes of Ar, Kr and Xe. The noble gases have been extracted using a thermal decrepitation procedure that enables partial deconvolution of the different fluid inclusion types, including variably saline aqueous, liquid carbon-dioxide and mixed aqueous-carbonic varieties.The variably saline (< 5-65 wt%) aqueous fluid inclusions dominate and have At-40/Ar-36 values of less than 2700 in most of the samples from across the region. These fluid inclusions have extremely variable molar Br/Cl values of 0.3-4 x 10(-3) and I/Cl values of 0.2-35 x 10(-6) and the fluids are interpreted to represent sedimentary formation waters derived from the upper crust that have dissolved variable quantities of halite (or scapolite) to achieve their ultra-high salinity.Fluid inclusions in a sample from the Snake Creek anticline in the Cloncurry District have the highest Ar-40/Ar-36 value of similar to 25,000 demonstrating a deep magmatic or metamorphic fluid origin in this case. A magmatic origin is favoured because this fluid is very similar to a fluid involved in Iron-Oxide-Copper-Gold (IOCG) mineralization at Ernest Henry that was also interpreted to have a magmatic origin, and because the aqueous fluid inclusions have Br/Cl of similar to 1-2 x 10(-3) and I/Cl of similar to-10 x 10(-6) that are similar to mantle-derived igneous rocks.Carbon-dioxide fluid inclusions dominate samples from the Knobby Quarry in the Mary Kathleen Fold Belt and have a maximum Ar-40/Ar-36 value of 6000-7000. These fluid inclusions are estimated to have a Ar-36 concentration of 1-4 ppb, that is similar to the range determined for aqueous fluid inclusions in all the other samples. In addition, aqueous and carbonic fluid inclusions in all the samples have similar Xe-129/Ar-36 plus Kr-84/Ar-36 values that are unfractionated, and close to the air-Air Saturated Water (ASW) range.These data are interpreted to indicate an independent and dominantly metamorphic origin for CO2, and the presence of mixed aqueous-carbonic fluid inclusions are attributed to fluid mixing and/or mingling, rather than fluid unmixing. However, the data do not preclude the presence of a minor magmatic CO2 component in the samples from the Knobby Quarry.Fluid inclusions in most of the samples from the Mary Kathleen Fold Belt have higher Br/Cl and I/Cl values, higher Ar-36 concentrations and lower maximum Ar-40/Ar-36 values than fluid inclusions in samples from the Cloncurry District. This suggests Na-Ca alteration in these different parts of the Eastern Mt Isa Block occurred independently. However, fluid inclusions associated with Na-Ca alteration in the Cloncurry District have a very similar composition to fluid inclusions in IOCG mineralization-stage quartz veins from Ernest Henry.These data are therefore compatible with a genetic relationship between regional Na-Ca alteration and IOCG mineralization in the Cloncurry District. In both cases the ultra-saline hydrothermal fluids had a dominant origin from sedimentary formation water, but are interpreted to contain a magmatic component sourced from the late-Isan Williams-Naraku Batholiths which may have driven fluid convection. (c) 2007 Elsevier B.V All rights reserved.

This work compares the performance of genetic programming (GP) against traditional fixed-length genome GA approaches on the optimization of wire antenna designs. We describe the implementation of a GP electromagnetic optimization system for wire structures. The results are compared with the traditional GA approach. Although the dimensionality of the search space is much higher for GP than GA, we find that the GP approach gives better results than GA for the same computational effort. In addition, we find that a more expressive antenna structure grammar, dramatically, improves the performance of the GP approach.

A fluid inclusion study of the Osborne IOCG deposit, in the Proterozoic Mt Isa Inlier of Australia, was conducted utilizing multiple geochemical techniques to generate a unique data set incorporating LA-ICP-MS and PIXE analyses. A two order magnitude range of Br/Cl values (0.2-18 x 10(-3)) indicate multiple sources of salinity. Mn/Fe ratios (0.04 - 0.32) of high salinity fluid inclusions reflect the redox state of the ore lens mineral assemblages, indicating they are the primary ore fluids. Cu concentrations are low in all fluids suggesting high fluid flux was required to form the 15.2 Mt deposit. Examination of the data obtained on the same fluid inclusion using the different micro-analytical methods provides a direct comparison of these increasingly widely used techniques and permits greater understanding of the chemistry of the ore forming fluids and of fluid processes.

Research Article| July 01, 2007 Distribution of Gold in Hypogene Ore at the Ernest Henry Iron Oxide Copper-Gold Deposit, Cloncurry District, NW Queensland A.R. Foster; A.R. Foster 1Economic Geology Research Unit, School of Earth and Environmental Sciences, James Cook University, Townsville, Q4811, Australia. *Née Brodie Search for other works by this author on: GSW Google Scholar P.J. Williams; P.J. Williams † 1Economic Geology Research Unit, School of Earth and Environmental Sciences, James Cook University, Townsville, Q4811, Australia. †Corresponding author. E-mail: patrick.williams@jcu.edu.au Search for other works by this author on: GSW Google Scholar C.G. Ryan C.G. Ryan 2CSIRO Exploration and Mining, School of Geosciences, Monash University, Melbourne 3168, Australia. Search for other works by this author on: GSW Google Scholar Exploration and Mining Geology (2007) 16 (3-4): 125–143. https://doi.org/10.2113/gsemg.16.3-4.125 Article history received: 13 Jan 2006 accepted: 06 Jan 2007 first online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation A.R. Foster, P.J. Williams, C.G. Ryan; Distribution of Gold in Hypogene Ore at the Ernest Henry Iron Oxide Copper-Gold Deposit, Cloncurry District, NW Queensland. Exploration and Mining Geology 2007;; 16 (3-4): 125–143. doi: https://doi.org/10.2113/gsemg.16.3-4.125 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu nav search search input Search input auto suggest search filter All ContentBy SocietyExploration and Mining Geology Search Advanced Search Abstract Petrographic studies, assay records, and laser ablation–inductively coupled plasma–mass spectrometer (LA-ICP-MS) analyses of major sulfides suggest nearly all of the gold at the Ernest Henry Cu-Au deposit occurs in the form of native gold or electrum (95–65 wt.% Au); sylvanite and dissolved gold in cobaltite, chalcopyrite, and pyrite make only minor contributions. LA-ICP-MS analyses of the gold contents of chalcopyrite gave from 8 to 139 ppb (mean = 56 ppb), more than an order of magnitude lower than those experimentally determined in chalcopyrite in equilibrium with native gold at the estimated mineralization temperatures (350°–450°C). Gold content is more variable in pyrite (1–400 ppb, mean = 77 ppb) and highest in narrow growth zones of a subordinate type of complexly zoned pyrite wherein it is associated with elevated As, Ag, Sn, Sb, Te, and Bi. Deposition of gold-electrum was closely associated with, but preceded some of the chalcopyrite deposition, as indicated by microtextures and lower bulk Au: Cu ratios in late-stage chalcopyrite-rich veins. Gold grains have maximum dimensions from <1 to 50 micrometers, and are heterogeneously distributed with most occurring in microscale clusters. Fifty-five out of 76 grains recorded in polished sections are in contact with both chalcopyrite and pyrite, and many of the rest are in sites where such a relationship could exist in the third dimension. The dominant textural sites are intergrowths with chalcopyrite in microveinlets cutting pyrite, and on faces of pyrite grains in contact with chalcopyrite. Scanning electron microscopy, electron microprobe analysis, and proton induced X-ray emission studies show that pyrite associated with gold includes complexly zoned, weakly zoned, arsenian, and arsenic-poor types. The textures are compatible with the possibility that most gold was deposited electrochemically as native metal on pyrite surfaces. The textural distribution of gold has important metallurgical implications given that the ore processing circuits at Ernest Henry and most other sulfide copper mines are designed to exclude pyrite (and arsenic) from concentrates. You do not currently have access to this article.

Proterozoic terranes in Australia contain several world class copper, lead and zinc deposits, however, in the Georgetown inlier there has been only limited base metal production. Recent exploration at the historic Einasleigh copper deposit has identified significant high grade copper (0.9 Mt at 3.3 % Cu). New U-Pb zircon and EMPA monazite age data from host rocks to the deposit support regional work that has identified a protracted, multiphase metamorphic history from ca. 1650 to 1500 Ma. A Re-Os age of molybdenite in the ore and monazite in related alteration suggests the ore in its current structural setting formed at ca. 1400 Ma. This does not coincide with a widely recognised Proterozoic metallogenic event but does coincide with Re-Os age data from the Mount Isa copper-lead-zinc system.

Recent discoveries east of Mt Isa such as Cannington (Ag-Pb-Zn) and Ernest Henry (Cu-Au-Co) have significantly increased the known metal endowment of the major Proterozoic metals province formed by the McArthur Basin and Mt Isa Inlier in northern Australia. The `Eastern Succession' or 'Cloncurry' ore systems include Cu-Au, Au-only, Pb-Zn-Ag and U-REE types that are quite distinct from deposits further west despite the broadly similar age and tectonic evolution of the host sequences. The abundant Cu-Au deposits exhibit no fundamental stratigraphic control and are localised by faults that channelled high temperature (300-500 degrees C) and very high salinity ore fluids at about the end of the ca 1620-1500 Ma Isan Orogeny. Circumstantial evidence points to a link with granitoids of the late to post-orogenic Williams-Naraku Batholiths. Sulfides were deposited through combinations of fluid cooling, wall-rock reactions and phase separation. In one case (Osborne deposit) it has been shown that mineralisation occurred at depths of more than 4.5 km. The Fe-oxide-Cu-Au association and styles of mineralisation in the largest deposits forge links with other Proterozoic provinces (e.g. Gawler Craton and Tennant Creek inlier). Pb-Zn-Ag occurrences are much rarer but include two major deposits (Cannington and Dugald River). The examples in the southeast of the area including Cannington are restricted to a <1680Ma metamorphosed siliciclastic sequence. They exhibit affinities with the giant deposit at Broken Hill including high-metamorphic-grade host rocks, skarn-like gangue and spatial association with various quartz-garnet, magnetite-rich, and gahnite-bearing lithologies, These deposits display evidence of a protracted evolution including substantial effects of late to post-orogenic alteration and ii is unclear whether they are products of a premetamorphic mineralising event or are coeval with the Cu-Au systems.

Creative remediation schemes have been implemented with success at petroleum-contaminated sites in Alaska and Canada during the past decade. Contaminated media have been landfarmed, amended with fertilizers, augmented with microbial products, and manipulated with engineered systems. Phytoremediation developments and use of biodegradable synthetic and polymeric resins for potential use with petroleum and xenobiotic contaminants are on the horizon. Treatment of supra-permafrost water and melt-water runoff with permeable reactive barriers and partitioning bioreactors is now possible. Cost and time limitations will likely continue to drive remediation decisions in the Arctic. Environmental policy, environmental constraints, and cost will dictate what technologies are appropriate for Antarctic clean-up, although the pressure of time is less acute because land transfer and liability are not drivers. This paper discusses some recent advances in remediation engineering for use in polar regions. Conceptual models are presented, and case study treatment costs and durations are highlighted to aid environmental decision-making.