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Ammonium is a common contaminant found in the soils and groundwater at former gasworks, associated with historical gas production and the storage and disposal of by-product. However, it can also be present in groundwater at gasworks sites from a variety of natural and other anthropogenic sources. This study evaluates the use of nitrogen isotope analysis at eight former gasworks sites in the UK as a forensic tool to differentiate between ammonium from gasworks and non-gasworks sources. It also provides an understanding of how the parent coal, gas-making technology and by-product processing can influence the presence of ammonium on a former gasworks, and the importance of understanding the site layout when sampling. Results of this study indicate that gasworks sources would be indicated typically by a δ 15 N of between −3.2 and +10.7‰, which correlate to published isotopic ranges specifically for coal and coal by-products. This broad range includes published values for the isotopic signature of parent coal ( δ 15 N of −3.2 to +6.3‰,), coal pyrolysis residue/tar ( δ 15 N of 4.2–10.7‰,), gas-purifier waste ( δ 15 N of 2–5‰) and coking-works-derived ammonium sulfate ( δ 15 N of −0.5‰). This suggests that gas-purification waste may have a distinct isotopic range compared to coal tar, a finding supported by results from Site A. Gasworks-sourced nitrogen typically had a lower δ 15 N value than non-gasworks sources, and predominantly in the δ 15 N ( N H 4 ) form. This study demonstrates nitrogen isotope analysis coupled with traditional hydrochemistry and a detailed site investigation is shown to have potential for use as part of the environmental forensic toolkit.

Plantar dislocation of the first metatarsophalangeal joint is a possible, albeit rare, injury to the foot. The mechanism has been attributed to a hyperflexion motion, with the hallux situated plantar to the first metatarsal head. In this article, we provide a case example of an open, plantar dislocation of the first metatarsophalangeal and perform a literature review of this rare injury. Based on x-ray analysis of the published cases, the sesamoids may or may not dislocate with the phalanx based off of the local capsuloligamentous anatomy. As a result, a modified Jahss classification (type 3A and type 3B) has been proposed to amend the existing system, adding plantar dislocations of the first metatarsophalangeal without (type 3A) and with (type 3B) sesamoid dislocation.

To make a power spectrum (PS) detection of the 21 cm signal from the Epoch of Reionisation (EoR), one must avoid/subtract bright foreground sources. Sources such as Fornax A present a modelling challenge due to spatial structures spanning from arc seconds up to a degree. We compare modelling with multi-scale (MS) CLEAN components to 'shapelets', an alternative set of basis functions. We introduce a new image-based shapelet modelling package, SHAMFI. We also introduce a new CUDA simulation code (WODEN) to generate point source, Gaussian, and shapelet components into visibilities. We test performance by modelling a simulation of Fornax A, peeling the model from simulated visibilities, and producing a residual PS. We find the shapelet method consistently subtracts large-angular-scale emission well, even when the angular-resolution of the data is changed. We find that when increasing the angular-resolution of the data, the MS CLEAN model worsens at large angular-scales. When testing on real MWA data, the expected improvement is not seen in real data because of the other dominating systematics still present. Through further simulation we find the expected differences to be lower than obtainable through current processing pipelines. We conclude shapelets are worthwhile for subtracting extended galaxies, and may prove essential for an EoR detection in the future, once other systematics have been addressed., Comment: 17 pages, 11 Figures, accepted for publication in Publications of the Astronomical Society of Australia (18/05/2020). "For the SHAMFI code, see: https://github.com/JLBLine/SHAMFI" . "For the SHAMFI documentation, see: https://shamfi.readthedocs.io/" . "For the WODEN code and documentation see: https://github.com/JLBLine/WODEN"

Responses of organisms to sub-lethal exposure of environmental stressors can be difficult to detect. We investigated phenotypic changes in the tissue of Caenorhabditis elegans via Raman spectroscopy, as well as survival and reproductive output when exposed to chronic low dose of exposure metals (copper, zinc or silver), an herbicide (diuron) and a pesticide (imidacloprid). Raman spectroscopy measures changes in phenotype by providing information about the molecular composition and relative abundance of biomolecules. Multivariate analysis was used to evaluate the significance of treatment phenotype segregation plots compared to controls. Dose-dependent responses were observed for copper, zinc, silver and diuron while imidacloprid exposure resulted in a small response over the tested concentrations. Concentration-dependent shifts in nematode biomolecular phenotype were observed for copper. Despite having a dose–dependent reproductive response, silver, diuron and imidaclorprid had inconsistent biological phenotype patterns. In contrast, there was a clear stepwise change between low concentrations (0.00625 - 0.5 mg/L) and higher concentration (1–2mg/L) of ionic zinc. The findings demonstrate that measuring phenotypic responses via Raman spectroscopy can provide an insight into the biomolecular mechanisms of toxicity. Despite the lack of consistency between survival and Raman-measured phenotypic changes, the results supports the effectiveness of Raman spectroscopy and multivariate analysis to detect sub-lethal responses of chemicals on whole organisms and to identify toxic effect thresholds. This article is protected by copyright. All rights reserved

We apply two methods to estimate the 21~cm bispectrum from data taken within the Epoch of Reionisation (EoR) project of the Murchison Widefield Array (MWA). Using data acquired with the Phase II compact array allows a direct bispectrum estimate to be undertaken on the multiple redundantly-spaced triangles of antenna tiles, as well as an estimate based on data gridded to the $uv$-plane. The direct and gridded bispectrum estimators are applied to 21 hours of high-band (167--197~MHz; $z$=6.2--7.5) data from the 2016 and 2017 observing seasons. Analytic predictions for the bispectrum bias and variance for point source foregrounds are derived. We compare the output of these approaches, the foreground contribution to the signal, and future prospects for measuring the bispectra with redundant and non-redundant arrays. We find that some triangle configurations yield bispectrum estimates that are consistent with the expected noise level after 10 hours, while equilateral configurations are strongly foreground-dominated. Careful choice of triangle configurations may be made to reduce foreground bias that hinders power spectrum estimators, and the 21~cm bispectrum may be accessible in less time than the 21~cm power spectrum for some wave modes, with detections in hundreds of hours., Comment: 19 pages, 10 figures, accepted for publication in PASA

Detection of the epoch of reionization H i signal requires a precise understanding of the intervening galaxies and AGN, both for instrumental calibration and foreground removal. We present a catalogue of 7394 extragalactic sources at 182 MHz detected in the RA = 0 field of the Murchison Widefield Array Epoch of Reionization observation programme. Motivated by unprecedented requirements for precision and reliability we develop new methods for source finding and selection. We apply machine learning methods to self-consistently classify the relative reliability of 9490 source candidates. A subset of 7466 are selected based on reliability class and signal-to-noise ratio criteria. These are statistically cross-matched to four other radio surveys using both position and flux density information. We find 7369 sources to have confident matches, including 90 partially resolved sources that split into a total of 192 sub-components. An additional 25 unmatched sources are included as new radio detections. The catalogue sources have a median spectral index of −0.85. Spectral flattening is seen towards lower frequencies with a median of −0.71 predicted at 182 MHz. The astrometric error is 7 arcsec compared to a 2.3 arcmin beam FWHM. The resulting catalogue covers ∼1400 deg² and is complete to approximately 80 mJy within half beam power. This provides the most reliable discrete source sky model available to date in the MWA EoR0 field for precision foreground subtraction., National Science Foundation (U.S.) (AST-0847753), National Science Foundation (U.S.) (AST-1410484), National Science Foundation (U.S.) (AST-1506024)

The compact configuration of Phase II of the Murchison Widefield Array (MWA) consists of both a redundant subarray and pseudo-random baselines, offering unique opportunities to perform sky-model and redundant interferometric calibration. The highly redundant hexagonal cores give improved power spectrum sensitivity. In this paper, we present the analysis of nearly 40 hours of data targeting one of the MWA's EoR fields observed in 2016. We use both improved analysis techniques presented in Barry et al. (2019) as well as several additional techniques developed for this work, including data quality control methods and interferometric calibration approaches. We show the EoR power spectrum limits at redshift 6.5, 6.8 and 7.1 based on our deep analysis on this 40-hour data set. These limits span a range in $k$ space of $0.18$ $h$ $\mathrm{Mpc^{-1}}$ $

Interferometric arrays seeking to measure the 21 cm signal from the Epoch of Reionization must contend with overwhelmingly bright emission from foreground sources. Accurate recovery of the 21 cm signal will require precise calibration of the array, and several new avenues for calibration have been pursued in recent years, including methods using redundancy in the antenna configuration. The newly upgraded Phase II of Murchison Widefield Array (MWA) is the first interferometer that has large numbers of redundant baselines while retaining good instantaneous UV-coverage. This array therefore provides a unique opportunity to compare redundant calibration with sky-model based algorithms. In this paper, we present the first results from comparing both calibration approaches with MWA Phase II observations. For redundant calibration, we use the package OMNICAL, and produce sky-based calibration solutions with the analysis package Fast Holographic Deconvolution (FHD). There are three principal results. (1) We report the success of OMNICAL on observations of ORBComm satellites, showing substantial agreement between redundant visibility measurements after calibration. (2) We directly compare OMNICAL calibration solutions with those from FHD, and demonstrate these two different calibration schemes give extremely similar results. (3) We explore improved calibration by combining OMNICAL and FHD. We evaluate these combined methods using power spectrum techniques developed for EoR analysis and find evidence for marginal improvements mitigating artifacts in the power spectrum. These results are likely limited by signal-to-noise in the six hours of data used, but suggest future directions for combining these two calibration schemes., 20 pages, 11 figures. Accepted to ApJ

Polycyclic aromatic hydrocarbons (PAHs) are a group of organic compounds consisting of two or more fused aromatic rings and are probably one of the most studied groups of organic chemicals in environmental research. PAHs originate mainly from anthropogenic processes, particularly from incomplete combustion of organic fuels. PAHs are distributed widely in particulate matter. Due to widespread sources and persistent characteristics, PAHs disperse through atmospheric transport and exist almost everywhere. Human beings are exposed to PAH mixtures in gaseous or particulate phases in ambient air. Long-term exposure to high concentrations of PAHs is associated with adverse health problems. This review identifies the main research and development themes in the measurement and occurrences of PAHs in dusts and particulates using a new approach to carrying out a literature review where many peer-review publications have been produced. The review extracts the most important research themes from a literature search using a combination of text mining and a more detailed review of selected papers from within the identified themes.

The Syrian hamster embryo (SHE) cell transformation assay (pH 6.7) has a reported sensitivity of 87% and specificity of 83%, and an overall concordance of 85% with in vivo rodent bioassay data. To date, the SHE assay is the only in vitro assay that exhibits multistage carcinogenicity. The assay uses morphological transformation, the first stage towards neoplasm, as an endpoint to predict the carcinogenic potential of a test agent. However, scoring of morphologically transformed SHE cells is subjective. We treated SHE cells grown on low-E reflective slides with 2,6-diaminotoluene, N-nitroso-N-ethylnitroguanidine, N-nitroso-N-methylurea, N-nitroso-N-ethylurea, EDTA, dimethyl sulphoxide (DMSO; vehicle control), methyl methanesulfonate, benzo[e]pyrene, mitomycin C, ethyl methanesulfonate, ampicillin or five different concentrations of benzo[a]pyrene. Macroscopically visible SHE colonies were located on the slides and interrogated using attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy acquiring five spectra per colony. The acquired IR data were analysed using Fisher's linear discriminant analysis (LDA) followed by principal component analysis (PCA)-LDA cluster vectors to extract major and minor discriminating wavenumbers for each treatment class. Each test agent vs. DMSO and treatment-induced transformed cells vs. corresponding non-transformed were classified by a unique combination of major and minor discriminating wavenumbers. Alterations associated with Amide I, Amide II, lipids and nucleic acids appear to be important in segregation of classes. Our findings suggest that a biophysical approach of ATR-FTIR spectroscopy with multivariate analysis could facilitate a more objective interrogation of SHE cells towards scoring for transformation and ultimately employing the assay for risk assessment of test agents.

As the global population is expected to reach 9 billion by 2050, humanity needs to balance an ever increasing demand for food, energy and natural resources, with sustainable management of ecosystems and the vital services that they provide. The intensification of agriculture, including the use of fertilisers from finite sources, has resulted in extensive soil degradation, which has increased food production costs and CO2 emissions, threatening food security. The Bioenergy sector has significant potential to contribute to the formation of a circular economy. This paper presents the scientific, regulatory and socioeconomic barriers to the use of the nutrient waste streams from biomass thermal conversion (ash) and anaerobic digestion (digestate) as sustainable soil amendments for use in place of traditional fertilisers. It is argued that whilst the ability of combined ash and digestate to remedy many threats to ecosystems and provide a market to incentivise the renewable bio-energy schemes is promising, a step-change is required to alter perceptions of ‘waste’, from an expensive problem, to a product with environmental and economic value. This can only be achieved by well-informed interactions between scientists, regulators and end users, to improve the spread and speed of innovation with this sector. Keywords: Digestate, Biomass ash, Soil conditioner, Environmental impact, Ecosystems, Regulation

We present first results from radio observations with the Murchison Widefield Array seeking to constrain the power spectrum of 21 cm brightness temperature fluctuations between the redshifts of 11.6 and 17.9 (113 and 75 MHz). 3 h of observations were conducted over two nights with significantly different levels of ionospheric activity. We use these data to assess the impact of systematic errors at low frequency, including the ionosphere and radio-frequency interference, on a power spectrum measurement. We find that after the 1–3 h of integration presented here, our measurements at the Murchison Radio Observatory are not limited by RFI, even within the FM band, and that the ionosphere does not appear to affect the level of power in the modes that we expect to be sensitive to cosmology. Power spectrum detections, inconsistent with noise, due to fine spectral structure imprinted on the foregrounds by reflections in the signal-chain, occupy the spatial Fourier modes where we would otherwise be most sensitive to the cosmological signal. We are able to reduce this contamination using calibration solutions derived from autocorrelations so that we achieve an sensitivity of 104 mK on comoving scales k ≲ 0.5 h Mpc[superscript −1]. This represents the first upper limits on the 21 cm power spectrum fluctuations at redshifts 12 ≲ z ≲ 18 but is still limited by calibration systematics. While calibration improvements may allow us to further remove this contamination, our results emphasize that future experiments should consider carefully the existence of and their ability to calibrate out any spectral structure within the EoR window., National Science Foundation (U.S.) (AST-0457585), National Science Foundation (U.S.) (AST-0821321), National Science Foundation (U.S.) (AST-1105835), National Science Foundation (U.S.) (AST-1410719), National Science Foundation (U.S.) (AST-1410484), National Science Foundation (U.S.) (AST-1411622), National Science Foundation (U.S.) (AST-1440343), National Science Foundation (U.S.) (1122374), National Science Foundation (U.S.) (PHY-0835713), National Science Foundation (U.S.) (CAREER-0847753), National Science Foundation (U.S.) (AST-0908884), United States. Air Force Office of Scientific Research (FA9550-0510247)

Responses of organisms to sublethal exposure of environmental stressors can be difficult to detect. We investigated phenotypic changes in the tissue of Caenorhabditis elegans via Raman spectroscopy, as well as survival and reproductive output when exposed to chronic low doses of metals (copper, zinc, or silver), an herbicide (diuron), and a pesticide (imidacloprid). Raman spectroscopy measures changes in phenotype by providing information about the molecular composition and relative abundance of biomolecules. Multivariate analysis was used to evaluate the significance of treatment phenotype segregation plots compared with controls. Dose-dependent responses were observed for copper, zinc, silver, and diuron, whereas imidacloprid exposure resulted in a small response over the tested concentrations. Concentration-dependent shifts in nematode biomolecular phenotype were observed for copper. Despite having a dose-dependent reproductive response, silver, diuron, and imidacloprid produced inconsistent biological phenotype patterns. In contrast, there was a clear stepwise change between low concentrations (0.00625-0.5 mg/L) and higher concentration (1-2 mg/L) of ionic zinc. The findings demonstrate that measuring phenotypic responses via Raman spectroscopy can provide insights into the biomolecular mechanisms of toxicity. Despite the lack of consistency between survival and Raman-measured phenotypic changes, the results support the effectiveness of Raman spectroscopy and multivariate analysis to detect sublethal responses of chemicals in whole organisms and to identify toxic effect thresholds. Environ Toxicol Chem 2018;37:920-930. © 2017 SETAC.

The current generation of experiments aiming to detect the neutral hydrogen signal from the Epoch of Reionisation (EoR) is likely to be limited by systematic effects associated with removing foreground sources from target fields. In this paper we develop a model for the compact foreground sources in one of the target fields of the MWA's EoR key science experiment: the `EoR1' field. The model is based on both the MWA's GLEAM survey and GMRT 150 MHz data from the TGSS survey, the latter providing higher angular resolution and better astrometric accuracy for compact sources than is available from the MWA alone. The model contains 5049 sources, some of which have complicated morphology in MWA data, Fornax A being the most complex. The higher resolution data show that 13% of sources that appear point-like to the MWA have complicated morphology such as double and quad structure, with a typical separation of 33~arcsec. We derive an analytic expression for the error introduced into the EoR two-dimensional power spectrum due to peeling close double sources as single point sources and show that for the measured source properties, the error in the power spectrum is confined to high $k_\bot$ modes that do not affect the overall result for the large-scale cosmological signal of interest. The brightest ten mis-modelled sources in the field contribute 90% of the power bias in the data, suggesting that it is most critical to improve the models of the brightest sources. With this hybrid model we reprocess data from the EoR1 field and show a maximum of 8% improved calibration accuracy and a factor of two reduction in residual power in $k$-space from peeling these sources. Implications for future EoR experiments including the SKA are discussed in relation to the improvements obtained., Comment: 16 pages, 8 figures, 3 tables. Accepted for publication in PASA

We present the first Murchison Widefield Array observations of the well-known cluster of galaxies Abell 3667 (A3667) between 105 and 241 MHz. A3667 is one of the best known examples of a galaxy cluster hosting a double radio relic and has been reported to contain a faint radio halo and bridge. The origins of radio halos, relics and bridges is still unclear, however galaxy cluster mergers seems to be an important factor. We clearly detect the North-West (NW) and South-East (SE) radio relics in A3667 and find an integrated flux density at 149 MHz of 28.1 +/- 1.7 and 2.4 +/- 0.1 Jy, respectively, with an average spectral index, between 120 and 1400 MHz, of -0.9 +/- 0.1 for both relics. We find evidence of a spatial variation in the spectral index across the NW relic steepening towards the centre of the cluster, which indicates an ageing electron population. These properties are consistent with higher frequency observations. We detect emission that could be associated with a radio halo and bridge. How- ever, due to the presence of poorly sampled large-scale Galactic emission and blended point sources we are unable to verify the exact nature of these features., 17 pages, 11 figures

Nanoparticles appear to induce toxic effects through a variety of mechanisms including generation of reactive oxygen species (ROS), physical contact with the cell membrane and indirect catalysis due to remnants from manufacture. The development and subsequent increasing usage of nanomaterials has highlighted a growing need to characterize and assess the toxicity of nanoparticles, particularly those that may have detrimental health effects such as carbon-based nanomaterials (CBNs). Due to interactions of nanoparticles with some reagents, many traditional toxicity tests are unsuitable for use with CBNs. Infrared (IR) spectroscopy is a non-destructive, high throughput technique, which is unhindered by such problems. We explored the application of IR spectroscopy to investigate the effects of CBNs on Gram-negative (Pseudomonas fluorescens) and Gram-positive (Mycobacterium vanbaalenii PYR-1) bacteria. Two types of IR spectroscopy were compared: attenuated total reflection Fourier-transform infrared (ATR-FTIR) and synchrotron radiation-based FTIR (SR-FTIR) spectroscopy. This showed that Gram-positive and Gram-negative bacteria exhibit differing alterations when exposed to CBNs. Gram-positive bacteria appear more resistant to these agents and this may be due to the protection afforded by their more sturdy cell wall. Markers of exposure also vary according to Gram status; Amide II was consistently altered in Gram-negative bacteria and carbohydrate altered in Gram-positive bacteria. ATR-FTIR and SR-FTIR spectroscopy could both be applied to extract biochemical alterations induced by each CBN that were consistent across the two bacterial species; these may represent potential biomarkers of nanoparticle-induced alterations. Vibrational spectroscopy approaches may provide a novel means of fingerprinting the effects of CBNs in target cells.

Risk assessment and remediation of contaminated land is inherently dependent on the contaminants present and their availability for interaction with soil biota. An ever-growing body of evidence suggests that current regulatory procedures over-estimate the 'true' fraction available to biota. Thus, a procedure that predicts the 'bioavailable fraction' would be useful for predicting 'actual' exposure limits and provide a more relevant basis for risk assessment. The aim of this paper is to address several important questions: "How should bioavailability be defined?" "What factors affect bioavailability measurement?" "To what extent have existing protocols measured bioavailability?" "What is actually measured by chemical techniques purported to determine bioavailability?" We offer two definitions (namely 'bioavailability' and 'bioaccessibility') and review commonly employed chemical extraction techniques to measure putative bioavailability. Relative advantages and disadvantages of the techniques are highlighted to elucidate underlying factors for the wide range of conclusions observed in the literature. Although the concept of bioavailability is implicit to contaminated land risk assessment and remediation, explicit reference to and use of adjustment factors is rare amongst regulatory bodies and remediators. Use of chemical determinants for bioavailability, applicable within current legislation and due consideration to inherent variability, are proposed and barriers to their implementation discussed.

Our ability to identify the mechanisms by which carbon-based nanomaterials (CBNs) exert toxicity in cells is constrained by the lack of standardized methodologies to assay endpoint effects. Herein we describe a method of mechanistically identifying the effects of various CBN types in both prokaryotic and eukaryotic cells using multi-beam synchrotron radiation-based Fourier-transform infrared imaging (SR-FTIRI) at diffraction-limited resolution. This technique overcomes many of the inherent difficulties of assaying nanotoxicity and demonstrates exceptional sensitivity in identifying the effects of CBNs in cells at environmentally-relevant concentrations. We identify key mechanisms of nanotoxicity as the alteration of Amide and lipid biomolecules, but propose more specific bioactivity of CBNs occurs as a result of specific interactions between CBN structural conformation and cellular characteristics. Keywords: Carbon nanoparticles, Multivariate analysis, Nanotoxicity, Spectroscopy, Synchrotron radiation

Experiments that pursue detection of signals from the Epoch of Reionization (EoR) are relying on spectral smoothness of source spectra at low frequencies. This article empirically explores the effect of foreground spectra on EoR experiments by measuring high-resolution full-polarization spectra for the 586 brightest unresolved sources in one of the Murchison Widefield Array (MWA) EoR fields using 45 h of observation. A novel peeling scheme is used to subtract 2500 sources from the visibilities with ionospheric and beam corrections, resulting in the deepest, confusion-limited MWA image so far. The resulting spectra are found to be affected by instrumental effects, which limit the constraints that can be set on source-intrinsic spectral structure. The sensitivity and power-spectrum of the spectra are analysed, and it is found that the spectra of residuals are dominated by point spread function sidelobes from nearby undeconvolved sources. We release a catalogue describing the spectral parameters for each measured source.

The Detection of redshifted 21 cm emission from the epoch of reionization (EoR) is a challenging task owing to strong foregrounds that dominate the signal. In this paper, we propose a general method, based on the delay spectrum approach, to extract HI power spectra that is applicable to tracking observations using an imaging radio interferometer (Delay Spectrum with Imaging Arrays (DSIA)). Our method is based on modelling the HI signal taking into account the impact of wide field effects such as the $w$-term which are then used as appropriate weights in cross-correlating the measured visibilities. Our method is applicable to any radio interferometer that tracks a phase center and could be utilized for arrays such as MWA, LOFAR, GMRT, PAPER and HERA. In the literature the delay spectrum approach has been implemented for near-redundant baselines using drift scan observations. In this paper we explore the scheme for non-redundant tracking arrays, and this is the first application of delay spectrum methodology to such data to extract the HI signal. We analyze 3 hours of MWA tracking data on the EoR1 field. We present both 2-dimensional ($k_\parallel,k_\perp$) and 1-dimensional (k) power spectra from the analysis. Our results are in agreement with the findings of other pipelines developed to analyse the MWA EoR data., Comment: 17 pages, 10 figures, accepted for publication in The Astrophysical Journal

We present the 21 cm power spectrum analysis approach of the Murchison Widefield Array Epoch of Reionization project. In this paper, we compare the outputs of multiple pipelines for the purpose of validating statistical limits cosmological hydrogen at redshifts between 6 and 12. Multiple, independent, data calibration and reduction pipelines are used to make power spectrum limits on a fiducial night of data. Comparing the outputs of imaging and power spectrum stages highlights differences in calibration, foreground subtraction and power spectrum calculation. The power spectra found using these different methods span a space defined by the various tradeoffs between speed, accuracy, and systematic control. Lessons learned from comparing the pipelines range from the algorithmic to the prosaically mundane; all demonstrate the many pitfalls of neglecting reproducibility. We briefly discuss the way these different methods attempt to handle the question of evaluating a significant detection in the presence of foregrounds., Comment: accepted to ApJ

With increasing production of carbon nanoparticles (CNPs), environmental release of these entities becomes an ever-greater inevitability. However, many questions remain regarding their impact on soil microorganisms. This study examined the effects of long or short multiwalled carbon nanotubes (MWCNTs), C60 fullerene and fullerene soot in Gram-negative bacteria. Attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy was applied to derive signature spectral fingerprints of effects. A concentration-dependent response in spectral alterations was observed for each nanoparticle type. Long or short MWCNTs and fullerene soot gave rise to similar alterations to lipids, Amide II and DNA. The extent of alteration varies with nanoparticle size, with smaller short MWCNTs resulting in greater toxicity than long MWCNTs. Fullerene soot was the least toxic. C60 results in the most distinct and largest overall alterations, notably in extensive protein alteration. This work demonstrates a novel approach for assaying and discriminating the effects of CNPs in target systems.

While prior research indicates that relationships exist between anxiety‐stability and working memory, and cognitive style and anxiety‐stability, they have not been considered together. The aim of this study was to consider how anxiety‐stability is related to working memory, gender and style in interaction. The sample consisted of 179 12–13‐year‐old Year 8 secondary comprehensive school pupils in the UK. Teachers rated the level of anxiety‐stability of pupils. Pupils completed an assessment of working memory efficiency, the information processing index (IPI). They also did the cognitive styles analysis to determine their positions on the two fundamental cognitive style dimensions, which were indicated by two ratios: the Wholist‐Analytic ratio and the Verbal‐Imagery ratio. Working memory capacity and cognitive style interacted in their relationship with anxiety‐stability, such that higher memory was associated with a greater increased stability for Wholist‐Verbalisers and Analytic‐Imagers than for Analytic‐...

The Murchison Widefield Array (MWA) is a Square Kilometre Array (SKA) Precursor. The telescope is located at the Murchison Radio--astronomy Observatory (MRO) in Western Australia (WA). The MWA consists of 4096 dipoles arranged into 128 dual polarisation aperture arrays forming a connected element interferometer that cross-correlates signals from all 256 inputs. A hybrid approach to the correlation task is employed, with some processing stages being performed by bespoke hardware, based on Field Programmable Gate Arrays (FPGAs), and others by Graphics Processing Units (GPUs) housed in general purpose rack mounted servers. The correlation capability required is approximately 8 TFLOPS (Tera FLoating point Operations Per Second). The MWA has commenced operations and the correlator is generating 8.3 TB/day of correlation products, that are subsequently transferred 700 km from the MRO to Perth (WA) in real-time for storage and offline processing. In this paper we outline the correlator design, signal path, and processing elements and present the data format for the internal and external interfaces., Comment: 17 pages, 9 figures. Accepted for publication in PASA. Some figures altered to meet astro-ph submission requirements

The exceptional sorptive ability of carbon nanomaterials (CNMs) for hydrophobic organic contaminants (HOCs) is driven by their characteristically large reactive surface areas and highly hydrophobic nature. Given these properties, it is possible for CNMs to impact on the persistence, mobility and bioavailability of contaminants within soils, either favourably through sorption and sequestration, hence reducing their bioavailability, or unfavourably through increasing contaminant dispersal. This review considers the complex and dynamic nature of both soil and CNM physicochemical properties to determine their fate and behaviour, together with their interaction with contaminants and the soil microflora. It is argued that assessment of CNMs within soil should be conducted on a case-by-case basis and further work to assess the long-term stability and toxicity of sorbed contaminants, as well as the toxicity of CNMs themselves, is required before their sorptive abilities can be applied to remedy environmental issues.

The Murchison Widefield Array (MWA) is a new low-frequency interferometric radio telescope built in Western Australia at one of the locations of the future Square Kilometre Array (SKA). We describe the automated radio-frequency interference (RFI) detection strategy implemented for the MWA, which is based on the AOFlagger platform, and present 72-231-MHz RFI statistics from 10 observing nights. RFI detection removes 1.1% of the data. RFI from digital TV (DTV) is observed 3% of the time due to occasional ionospheric or atmospheric propagation. After RFI detection and excision, almost all data can be calibrated and imaged without further RFI mitigation efforts, including observations within the FM and DTV bands. The results are compared to a previously published Low-Frequency Array (LOFAR) RFI survey. The remote location of the MWA results in a substantially cleaner RFI environment compared to LOFAR's radio environment, but adequate detection of RFI is still required before data can be analysed. We include specific recommendations designed to make the SKA more robust to RFI, including: the availability of sufficient computing power for RFI detection; accounting for RFI in the receiver design; a smooth band-pass response; and the capability of RFI detection at high time and frequency resolution (second and kHz-scale respectively)., Comment: Accepted for publication in PASA

Detection of 21~cm emission of HI from the epoch of reionization, at redshifts z>6, is limited primarily by foreground emission. We investigate the signatures of wide-field measurements and an all-sky foreground model using the delay spectrum technique that maps the measurements to foreground object locations through signal delays between antenna pairs. We demonstrate interferometric measurements are inherently sensitive to all scales, including the largest angular scales, owing to the nature of wide-field measurements. These wide-field effects are generic to all observations but antenna shapes impact their amplitudes substantially. A dish-shaped antenna yields the most desirable features from a foreground contamination viewpoint, relative to a dipole or a phased array. Comparing data from recent Murchison Widefield Array observations, we demonstrate that the foreground signatures that have the largest impact on the HI signal arise from power received far away from the primary field of view. We identify diffuse emission near the horizon as a significant contributing factor, even on wide antenna spacings that usually represent structures on small scales. For signals entering through the primary field of view, compact emission dominates the foreground contamination. These two mechanisms imprint a characteristic "pitchfork" signature on the "foreground wedge" in Fourier delay space. Based on these results, we propose that selective down-weighting of data based on antenna spacing and time can mitigate foreground contamination substantially by a factor ~100 with negligible loss of sensitivity., Published in ApJ

We compare first order (refractive) ionospheric effects seen by the Murchison Widefield Array (MWA) with the ionosphere as inferred from Global Positioning System (GPS) data. The first order ionosphere manifests itself as a bulk position shift of the observed sources across an MWA field of view. These effects can be computed from global ionosphere maps provided by GPS analysis centres, namely the Center for Orbit Determination in Europe (CODE), using data from globally distributed GPS receivers. However, for the more accurate local ionosphere estimates required for precision radio astronomy applications, data from local GPS networks needs to be incorporated into ionospheric modelling. For GPS observations, the ionospheric parameters are biased by GPS receiver instrument delays, among other effects, also known as receiver Differential Code Biases (DCBs). The receiver DCBs need to be estimated for any non-CODE GPS station used for ionosphere modelling, a requirement for establishing dense GPS networks in arbitrary locations in the vicinity of the MWA. In this work, single GPS station-based ionospheric modelling is performed at a time resolution of 10 minutes. Also the receiver DCBs are estimated for selected Geoscience Australia (GA) GPS receivers, located at Murchison Radio Observatory (MRO1), Yarragadee (YAR3), Mount Magnet (MTMA) and Wiluna (WILU). The ionospheric gradients estimated from GPS are compared with the ionospheric gradients inferred from radio source position shifts observed with the MWA. The ionospheric gradients at all the GPS stations show a correlation with the gradients observed with the MWA. The ionosphere estimates obtained using GPS measurements show promise in terms of providing calibration information for the MWA.

We confirm our recent prediction of the "pitchfork" foreground signature in power spectra of high-redshift 21 cm measurements where the interferometer is sensitive to large-scale structure on all baselines. This is due to the inherent response of a wide-field instrument and is characterized by enhanced power from foreground emission in Fourier modes adjacent to those considered to be the most sensitive to the cosmological H I signal. In our recent paper, many signatures from the simulation that predicted this feature were validated against Murchison Widefield Array (MWA) data, but this key pitchfork signature was close to the noise level. In this paper, we improve the data sensitivity through the coherent averaging of 12 independent snapshots with identical instrument settings and provide the first confirmation of the prediction with a signal-to-noise ratio > 10. This wide-field effect can be mitigated by careful antenna designs that suppress sensitivity near the horizon. Simple models for antenna apertures that have been proposed for future instruments such as the Hydrogen Epoch of Reionization Array and the Square Kilometre Array indicate they should suppress foreground leakage from the pitchfork by ~40 dB relative to the MWA and significantly increase the likelihood of cosmological signal detection in these critical Fourier modes in the three-dimensional power spectrum., Accepted for publication in ApJ Letters, 6 pages, 2 figures

This paper reports the construction of a teacher rating instrument designed to monitor the social and emotional development of school age children and young people (4–17 years). The instrument was developed by reviewing previously implemented checklists to build an extensive list of behavioural and emotional criteria and through the use of focus groups to establish the views of key stakeholders. The criteria were categorized according to three areas: conduct, emotion and learning. The initial instrument of 21 items was piloted and amended accordingly. The final trial of the instrument was carried out on a sample of 7285 pupils from a cross‐section of UK schools. A principal component factor analysis confirmed the division of the scale into three factors. The instrument was supported by trends showing that the distributions were different for different types of schools and between males and females. The final version of the instrument was amended to include 15 items, five in each category (conduct, emotion...

Carbon nanotubes (CNTs) are considered promising materials in nanotechnology. We quantified CNT accumulation by the alga Desmodesmus subspicatus. Cells were exposed to radiolabeled CNTs ((14)C-CNTs; 1 mg/L) to determine uptake and association, as well as elimination and dissociation in clear media. Attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR) was used to detect effects of CNTs on algae. CNT-cell interactions were visualized by electron microscopy and related to alterations in their cell composition. A concentration factor of 5000 L/kg dry weight was calculated. Most of the material agglomerated around the cells, but single tubes were detected in the cytoplasm. Computational analyses of the ATR-FTIR data showed that CNT treated algae differed from controls at all sampling times. CNT exposure changed the biochemical composition of cells. The fact that CNTs are bioavailable for algae and that they influence the cell composition is important with regard to environmental risk assessment of this nanomaterial.

Astronomical widefield imaging of interferometric radio data is computationally expensive, especially for the large data volumes created by modern non-coplanar many-element arrays. We present a new widefield interferometric imager that uses the w-stacking algorithm and can make use of the w-snapshot algorithm. The performance dependencies of CASA's w-projection and our new imager are analysed and analytical functions are derived that describe the required computing cost for both imagers. On data from the Murchison Widefield Array, we find our new method to be an order of magnitude faster than w-projection, as well as being capable of full-sky imaging at full resolution and with correct polarisation correction. We predict the computing costs for several other arrays and estimate that our imager is a factor of 2-12 faster, depending on the array configuration. We estimate the computing cost for imaging the low-frequency Square-Kilometre Array observations to be 60 PetaFLOPS with current techniques. We find that combining w-stacking with the w-snapshot algorithm does not significantly improve computing requirements over pure w-stacking. The source code of our new imager is publicly released., Accepted for publication in MNRAS

As soils represent a major sink for most pesticides, factors influencing pesticide degradation are essential in identifying their potential environmental risk. Desorption of (14)C-azoxystrobin was investigated over time in two soils under sterile and non-sterile conditions using exhaustive (solvent) and non-exhaustive (aqueous) methods. Desorption data were fitted to a two-compartment model, differentiating between fast and slow desorbing fractions. With increased ageing, rapid desorption (Frap) (bioaccessibility) decreased with corresponding increases in slowly desorbing fractions (F(slow)). The rapid desorption rate constant (k(fast)) was not affected by ageing, sterility or extraction solvent. The non-exhaustive extractions had similar desorption profiles; whereas exhaustive extractions in aged soils had the highest F(rap). In non-sterile soil, F(rap) was lower resulting in higher F(slow), while desorption rates remained unaffected. Organic matter (OM) reduces F(rap); but not desorption rates. Microorganisms and OM enhanced ageing effects, reducing the fraction of fast desorbing chemicals and potentially the bioaccessibility of pesticides in soil.

We present new low-frequency observations of the nearby radio galaxy Fornax A at 154 MHz with the Murchison Widefield Array, microwave flux-density measurements obtained from WMAP and Planck data, and gamma-ray flux densities obtained from Fermi data. We also compile a comprehensive list of previously published images and flux-density measurements at radio, microwave and X-ray energies. A detailed analysis of the spectrum of Fornax A between 154 MHz and 1510 MHz reveals that both radio lobes have a similar spatially-averaged spectral index, and that there exists a steep-spectrum bridge of diffuse emission between the lobes. Taking the spectral index of both lobes to be the same, we model the spectral energy distribution of Fornax A across an energy range spanning eighteen orders of magnitude, to investigate the origin of the X-ray and gamma-ray emission. A standard leptonic model for the production of both the X-rays and gamma-rays by inverse-Compton scattering does not fit the multi-wavelength observations. Our results best support a scenario where the X-rays are produced by inverse-Compton scattering and the gamma-rays are produced primarily by hadronic processes confined to the filamentary structures of the Fornax A lobes., Comment: 16 pages, 11 figures

The Murchison Widefield Array (MWA) has collected hundreds of hours of Epoch of Reionization (EoR) data and now faces the challenge of overcoming foreground and systematic contamination to reduce the data to a cosmological measurement. We introduce several novel analysis techniques such as cable reflection calibration, hyper-resolution gridding kernels, diffuse foreground model subtraction, and quality control methods. Each change to the analysis pipeline is tested against a two dimensional power spectrum figure of merit to demonstrate improvement. We incorporate the new techniques into a deep integration of 32 hours of MWA data. This data set is used to place a systematic-limited upper limit on the cosmological power spectrum of $\Delta^2 \leq 2.7 \times 10^4$ mK$^2$ at $k=0.27$ h~Mpc$^{-1}$ and $z=7.1$, consistent with other published limits, and a modest improvement (factor of 1.4) over previous MWA results. From this deep analysis we have identified a list of improvements to be made to our EoR data analysis strategies. These improvements will be implemented in the future and detailed in upcoming publications., Comment: 21 pages, 16 figures, accepted to ApJ

A case-study using interview and observation investigated on-the-job training in manufacturing companies to consider the implications for personnel professionals. The findings were that training was undertaken by peer colleagues who had received very restricted trainer training, and the training was wholly outside the oversight of personnel professionals. Developments were proposed which, while they would apply primarily to the case-study organisations, might well be appropriate for more general implementation.

A pool of 116 14-18-year-old secondary school pupils who had been given the computer-presented Cognitive Styles Analysis was used to provide two sub-samples to explore the relationship between style and motor skills and sports performance. The Motor Skills sub-sample of 69 (32 males and 37 females) did a battery of motor skills tests. A factor analysis suggested four skills factors - bodily movement, interactive skills, mechanical skills and aiming. All of these except the mechanical skills showed a significant relationship to style. The Sports Performance sub-sample of 99 (46 males and 53 females) were rated on a five-point scale by their teachers on performance in rugby, soccer and cricket for the boys, and hockey, netball and tennis for the girls. Here, there was a significant effect of style for tennis but not for the team games. The findings were discussed in terms of their practical implications.

The behaviours of 207 (92 male and 115 female) 15-18-year-old Kuwaiti secondary school pupils were assessed, together with a rating of their home educational background and cognitive style. The teachers of Arabic and of mathematics independently rated the behaviour of their pupils on a 31-item pupil behaviour questionnaire, and home educational background was rated by the Social Officer in each school. The position of pupils on the Wholist-Analytic and Verbal-Imagery dimensions of cognitive style was assessed by means of the Arabic version of the computer-presented Cognitive Styles Analysis . A factor analysis of the questionnaire items indicated four factors: conduct behaviour, learning behaviour, stability and physical well-being. With conduct and learning behaviour, the overall level was higher for females than males and also improved as parents' educational level increased. While conduct behaviour did not vary much with style, learning behaviour was significantly lower for the Analytics than the Wholi...

Individuals differences in information processing related to cognitive style were investigated by EEG recording during cognitive tasks. Fifteen adults received the Cognitive Styles Analysis which assessed their positions on two dimensions: the wholist-analytic and the verbal-imagery. The EEG from midline, paramedial and lateral electrode clusters was recorded, while subjects viewed words presented at different rates. A button was pressed when a word was in a target conceptual category. Off-line analysis produced spectral powers for delta, theta, alpha, beta 1, beta 2 and gamma bands. For the midline, the wholists had higher output than analytics in theta and alpha, but lower in gamma. In the paramedial cluster, verbalisers had greater right power than imagers for all bands except alpha. Further, the overall power was greater on the right for imagers than verbalisers frontally, and the converse occipitally. In the lateral grouping, the wholist-verbalisers had greater overall power left antero-temporally than other sub-groups.

The aim of the study was to investigate the relationship between learners' cognitive styles and their instructional preferences. The sample consisted of 240 business studies students at a UK university. Subjects' cognitive styles were assessed using theCognitive Styles Analysis (which assesses the wholist-analytical and verbaliser-imager dimensions of style) and their instructional preferences assessed using an instructional preferences inventory which consisted of three sub-inventories (instructional method, instructional media and assessment method). Overall subjects favoured dependent methods, print based media and informal assessment methods. There was a significant main effect of wholist-analytical style on collaborative method preference (role play, group discussions and business games) and non-print based media preference (overhead transparencies, slides and videos). There was an interaction of the two dimensions of style and gender in their effect on informal assessment method preferences (individual and group assignments and multiple choice and short answertype questions). The findings are discussed in terms of: (i) models of the cognitive style construct; (ii) the practical implications of individual differences in style and preference.

Eighty 11-year-old pupils (40 males and 40 females) from an urban primary school were assessed for cognitive style by means of the Cognitive Styles Analysis which indicated their positions on each of the two style dimensions, the Wholist-Analytic and the Verbal-Imagery. They then studied parts of three CD-ROM multi-media packages on science topics and after each, completed a multiple choice recall test. An indication of their performance on traditionally taught science was taken to be the performance on science SATs at 11 years. A comparison between multi-media and traditional work indicated that, (a) in terms of overall science performance (traditional and multi-media), Wholist-Imagers and Analytic-Verbalisers were superior to Wholist-Verbalisers and Analytic-Imagers, and (b) Analytics did better on traditional work than multi-media, with the reverse for the Wholists. With the multi-media materials there were three modes of presentation—picture and sound (PS), picture and text (PT), and picture, text and sound (PTS). Female Wholist-Imagers and Analytic-Verbalisers were better with PS than PT, with the reverse for Wholist-Verbalisers and Analytic-Imagers, while the opposite applied for males. For all style and gender groups performance was best with PTS. The findings are discussed in terms of their practical implications and further research.

Two-hundred 10–15 yr old students from a school in the UK for children from a Yemeni background were assessed for cognitive style by means of the Cognitive Styles Analysis . Based on their scores, students were placed on two dimensions: Wholist–Analytic and Verbal– Imagery. Half of the sample read three prose passages with a 20-question recall test after each. The other half received the same passages augmented with additional structuring features, (a) format structure as paragraph headings (Passage 2), and (b) conceptual structure as a summary inserted either after or before the main passage (Passages 1 and 3, respectively). The results suggested that pupils improved most with age on the content that suited their style, female Wholists and male Analytics benefitted most from the addition of structure, and, finally, with age the Verbalizers gained more with a summary added after the main passage and the Imagers with it inserted before. The results are discussed in terms of style effects on developmental trends in strategy development and gender differences in information processing.

Summary Background. Aims. Sample. Method. Results. Conclusion. The paper considers aberrant behaviour in the context of cognitive style with reference to both diagnosis and treatment. The aims of the study were to investigate whether the style of pupils with behaviour problems was different from that of children with no reported problems, and also to consider how pupils of different style manifested their problem behaviours. The sample comprised 83 male pupils aged 10‐18 years from two residential special schools. The sample were given the Cognitive Styles Analysis to assess their positions on the Wholist‐Analytic and Verbal‐Imagery style dimensions. The pupil records of the special school pupils who were at the extreme of the style dimensions were also examined. When their style characteristics were contrasted with a Comparison Sample of 413 12‐16‐year‐old males attending 10 secondary schools, the special school pupils had a significantly higher proportion of both Wholists and Verbalisers, than the Compa...

Cognitive style, gender and conduct behaviour in secondary school pupils The tutor group/form teachers of a total of 341 pupils from two schools, A (Year 10, age 14-15 years) and B (Year 11, age 15-16 years), were asked to rate the classroom conduct behaviour of their pupils on a five-point scale from very poor to very good. The cognitive styles of the pupils were assessed by means of the Cognitive Styles Analysis, which indicated their positions on each of two style dimensions, Wholist-Analytic and Verbal-Imagery. There was a significant interaction between gender and the Wholist-Analytic style in their effect on behaviour, with the females behaving better than the males, and the male Wholists being the worst behaved. The findings are discussed in terms of the practical implications for schooling.

The positions of 86 (47 female and 39 male) first‐year university business studies students on the two fundamental cognitive style dimensions (Wholist‐Analytic and Verbal‐Imagery) were assessed by means of the Cognitive Styles Analysis. Their self‐perception as learner was determined using a questionnaire given at the end of the first semester to determine their opinions of the subject modules that they had studied. Their performance in the three subject areas, information technology, accounting and management was obtained from their module assessment scores. Analysis of these data indicated three significant effects. (1) Sex and subject interacted in their effect on overall self‐perception/performance with the females being superior on management and the males on information technology and accounting. (2) Wholist‐Analytic style and subject interacted in their effect on self‐perception versus performance such that: (a) performance varied with style in line with the processing requirements of the ...