The use of Pb isotope ratios determined by magnetic sector ICP-MS for tracing Pb pollution in marine sediments near Casey Station, East Antarctica

Magnetic sector inductively coupled plasma mass spectrometry (ICP-SMS) was used to measure lead concentrations and isotope ratios in marine sediments and other samples collected from near the Australian Antarctic Station Casey. Precisions obtained from the repetitive analysis of a standard Broken Hill Pb sample at a concentration of approximately 40 ng g-1 in solution were less than plus or minus 0.2% for ratios involving 204Pb, and less than plus or minus 0.1% for those referenced to 206Pb or 207Pb (n ~ 12 replicates over 2 days, values as 1s). Ratios were accurate to within less than plus or minus 0.1% for the analysis of this standard sample. Comparative measurements between ICP-SMS and TIMS had typical differences in values of less than 0.4% for contaminated samples, irrespective of ratio. For marine sediment samples with Pb concentrations in the sample digest of greater than 10 ng g-1, instrumental capability was characterised by isotopic precisions ranging from 0.1-0.5% (1s) for ratios involving 204Pb, and less than 0.25% (1s) for ratios with 206Pb or 207Pb as the basis (typically found from triplicate analyses). For sediments of low Pb concentration (less than 10 ng g-1 in the sample digest), isotope ratios to 204Pb were found to be limited by instrument counting statistics when using standard ICP-SMS. To help overcome this problem, Pb isotope ratios for these samples were measured with a capacitive decoupling Pt guard electrode employed, offering considerable signal enhancement (5-10x). These natural background sediments were found to display typical Pb isotope ratios of 40.5, 15.5, 18.6 and 1.19 for 208Pb/204Pb, 207Pb/204Pb, 206Pb/204Pb and 206Pb/207Pb. For comparison, the most contaminated samples had Pb isotope ratios of approximately 36.2, 15.4, 16.4 and 1.06 for 208Pb/204Pb, 207Pb/204Pb, 206Pb/204Pb and 206Pb/207Pb, respectively. Evidence of simple two component mixing between anthropogenic and natural geogenic Pb was found near Casey Station. Runoff from the Thala Valley tip site, adjacent to the bay, was identified as a clear source of Pb pollution, with impacted sediments displaying an isotopic signature approaching that of abandoned lead batteries collected from the tip. These batteries possessed Pb isotope ratios identical to Australian Broken Hill lead. In this study, the use of Pb isotope data has proved to be a sensitive method of assessing contamination levels in the Antarctic marine environment adjacent to a waste disposal site. Lead isotope ratios have proved superior to simple elemental concentration determinations when distinguishing between impacted and non-impacted samples. ICP-SMS has been shown to offer relatively fast, accurate and cost effective Pb isotope ratios, with precisions suitable for many environmental applications

Hydropyrolysis of high molecular weight organic matter in Murchison

Hydropyrolysis of the Murchison macromolecular material releases polyaromatic compounds including phenanthrene, carbazole, fluoranthene, pyrene, chrysene, perylene, benzoperylene and coronene units with varying degrees of alklyation

HEREFORD AND WORCESTER (Reino Unido). Canales (1785?). 1:49100

Escala gráfica de 5 millas [= 16,4 cm]. Orientado con lis en rosa de ocho vientosOrografía a trazosRelación de las parroquias adyacentes al recorrido del canal, indicadas por clave numéricaFigura una tabla con datos sobre la longitud, elevación y caida de los diversos tramos del canalForma parte de la Colección Mendoz

In-situ nanoSIMS measurements of isotopic hotspots in the CM2 meteorite Cold Bokkeveld

Previous studies have identified iso-topic hotspots in insoluble organic matter (IOM) from carbonaceous chondrites. The origins and formation mechanisms of these hotspots and the host IOM are a matter of ongoing debate. For example, it is not clear whether D and 15N enrichments in IOM formed within a common organic precursor in cold interstellar environments or due to irradiation of organic material in the early Solar System. It is also unclear what effect parent body processes would have had with regard to the alteration of meteoritic IOM. In order to address these issues, more recent studies have attempted to make in-situ measurements of isotopic anomalies in IOM. In this study we present in-situ NanoSIMS isotopic analyses of material within a sample of the CM2 meteorite Cold Bokkeveld, comparing the distribution of hotspots and bulk H, C and N isotopic composition in the rims and interiors of altered chondrules

DenseReg: fully convolutional dense shape regression in-the-wild

In this paper we propose to learn a mapping from image pixels into a dense template grid through a fully convolutional network. We formulate this task as a regression problem and train our network by leveraging upon manually annotated facial landmarks “in-the-wild”. We use such landmarks to establish a dense correspondence field between a three-dimensional object template and the input image, which then serves as the ground-truth for training our regression system. We show that we can combine ideas from semantic segmentation with regression networks, yielding a highly-accurate ‘quantized regression’ architecture. Our system, called DenseReg, allows us to estimate dense image-to-template correspondences in a fully convolutional manner. As such our network can provide useful correspondence information as a stand-alone system, while when used as an initialization for Statistical Deformable Models we obtain landmark localization results that largely outperform the current state-of-the-art on the challenging 300W benchmark. We thoroughly evaluate our method on a host of facial analysis tasks, and demonstrate its use for other correspondence estimation tasks, such as the human body and the human ear. DenseReg code is made available at http://alpguler.com/DenseReg.html along with supplementary materials

Hybrid Two-step Preparation of Nanosized MgAl Layered Double Hydroxides for CO₂ Adsorption

Hybrid Two-step synthesis method for preparation of MgAl LDHs materials for CO2 adsorption has been employed because of the features of fast micromixing and enhanced mass transfer by using a ‘T-mixer’ reactor. MgAl LDHs with different morphologies were successfully obtained by three different synthesis routes: ultrasonication-intensified in ‘T-mixer’ (TU-LDHs), conventional co-precipitation (CC-LDHs) and ultrasonic-intensified in ‘T-mixer’ pretreatment followed by conventional co-precipitation (TUC-LDHs). The synthesized samples characterized by the XRD showed that LDHs formed a typical layered double hydroxide structure and no other impurities were identified in the compound. The SEM and TEM analyses also confirmed that the size distribution of TUC-LDHs was relatively uniform (with an average size of approximate 100 nm) and layered structure was clearly visible. The BET characterization indicated that such LDHs had a large surface area (235 m2 g−1), which makes it a promising adsorbent material for CO2 capture in practical application. It can be found that the CO2 adsorption capacities of TU-LDHs, CC-LDHs and TUC-LDHs at 80°C were 0.30, 0.22 and 0.28 mmol g−1, respectively. The CO2 adsorption capacities of TU-LDHs, CC-LDHs and TUC-LDHs at 200°C were 0.33, 0.25 and 0.36 mmol g−1, respectively. The order of CO2 adsorption capacity to reach equilibrium at 80°C seen in Avrami model is: TU-LDHs > TUC-LDHs > CC-LDHs. The CO2 adsorption/desorption cycling test reveals that TU-LDHs and TUC-LDHs have good adsorption stability than CC-LDHs

Dawning of a new ERA: Environmental Risk Assessment of antibiotics and their potential to select for antimicrobial resistance

This is the final version. Available on open access from Elsevier via the DOI in this recordAntibiotics and antimicrobials are used, misused and overused in human and veterinary medicine, animal husbandry and aquaculture. These compounds can persist in both human and animal waste and then enter the environment through a variety of mechanisms. Though generally measured environmental concentrations (MECs) of antibiotics in aquatic systems are significantly lower than point of therapeutic use concentrations, there is increasing evidence that suggests these concentrations may still enrich antimicrobial resistant bacteria. In light of this evidence, a rigorous and standardised novel methodology needs to be developed which can perform environmental risk assessment (ERA) of antimicrobials in terms of their selective potential as well as their environmental impact, to ensure that diffuse and point source discharges are safe. This review summarises and critically appraises the current methodological approaches that study selection at below point of therapeutic use, or sub-inhibitory, concentrations of antibiotics. We collate and compare selective concentration data generated to date. We recommend how these data can be interpreted in line with current ERA guidelines; outlining and describing novel concepts unique to risk assessment of AMR (such as direct selection of AMR or increased persistence of AMR). We consolidate terminology used thus far into a single framework that could be adopted moving forward, by proposing predicted no effect concentrations for resistance (PNECRs) and predicted no effect concentrations for persistence (PNECPs) be determined in AMR risk assessment. Such a framework will contribute to antibiotic stewardship and by extension, protection of human health, food security and the global economy

Face Normals "in-the- wild" using Fully Convolutional Networks

In this work we pursue a data-driven approach to the problem of estimating surface normals from a single intensity image, focusing in particular on human faces. We introduce new methods to exploit the currently available facial databases for dataset construction and tailor a deep convolutional neural network to the task of estimating facial surface normals in-the-wild. We train a fully convolutional network that can accurately recover facial normals from images including a challenging variety of expressions and facial poses. We compare against state-of-the-art face Shape-from-Shading and 3D reconstruction techniques and show that the proposed network can recover substantially more accurate and realistic normals. Furthermore, in contrast to other existing face-specific surface recovery methods, we do not require the solving of an explicit alignment step due to the fully convolutional nature of our network