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The Murchison Widefield Array (MWA) is an open access telescope dedicated to studying the low-frequency (80–300 MHz) southern sky. Since beginning operations in mid-2013, the MWA has opened a new observational window in the southern hemisphere enabling many science areas. The driving science objectives of the original design were to observe 21 cm radiation from the Epoch of Reionisation (EoR), explore the radio time domain, perform Galactic and extragalactic surveys, and monitor solar, heliospheric, and ionospheric phenomena. All together
programs recorded 20 000 h producing 146 papers to date. In 2016, the telescope underwent a major upgrade resulting in alternating compact and extended configurations. Other upgrades, including digital back-ends and a rapid-response triggering system, have been developed since the original array was commissioned. In this paper, we review the major results from the prior operation of the MWA and then discuss the new science paths enabled by the improved capabilities. We group these science opportunities by the four original science themes but also include ideas for directions outside these categories.
We have observed the G23 field of the Galaxy AndMass Assembly (GAMA) survey using the Australian Square Kilometre Array Pathfinder (ASKAP) in its commissioning phase to validate the performance of the telescope and to characterise the detected galaxy populations. This observation covers ~48 deg2 with synthesised beam of 32.7 arcsec by 17.8 arcsec at 936MHz, and ~39 deg2 with synthesised beam of 15.8 arcsec by 12.0 arcsec at 1320MHz. At both frequencies, the root-mean-square (r.m.s.) noise is ~0.1 mJy/beam. We combine these radio observations with the GAMA galaxy data, which includes spectroscopy of galaxies that are i-band selected with a magnitude limit of 19.2. Wide-field Infrared Survey Explorer (WISE) infrared (IR) photometry is used to determine which galaxies host an active galactic nucleus (AGN). In properties including source counts, mass distributions, and IR versus radio luminosity relation, the ASKAP-detected radio sources behave as expected. Radio galaxies have higher stellar mass and luminosity in IR, optical, and UV than other galaxies. We apply optical and IR AGN diagnostics and find that they disagree for ~30% of the galaxies in our sample. We suggest possible causes for the disagreement. Some cases can be explained by optical extinction of the AGN, but for more than half of the cases we do not find a clear explanation. Radio sources aremore likely (~6%) to have an AGN than radio quiet galaxies (~1%), but the majority of AGN are not detected in radio at this sensitivity.
The GaLactic and Extragalactic All-sky Murchison Widefield Array survey is a radio continuum survey at 72–231 MHz of the whole sky south of declination +30º, carried out with the Murchison Widefield Array. In this paper, we derive source counts from the GaLactic and Extragalactic All-sky Murchison data at 200, 154, 118, and 88 MHz, to a flux density limit of 50, 80, 120, and 290 mJy respectively, correcting for ionospheric smearing, incompleteness and source blending. These counts are more accurate than other counts in the literature at similar frequencies as a result of the large area of sky covered and this survey’s sensitivity to extended emission missed by other surveys. At S154 MHz > 0.5 Jy, there is no evidence of flattening in the average spectral index (α ≈ −0.8 where S ∝ vα) towards the lower frequencies. We demonstrate that the Square Kilometre Array Design Study model by Wilman et al. significantly underpredicts the observed 154-MHz GaLactic and Extragalactic All-sky Murchison counts, particularly at the bright end. Using deeper Low-Frequency Array counts and the Square Kilometre Array Design Study model, we find that sidelobe confusion dominates the thermal noise and classical confusion at v ≳ 100 MHz due to both the limited CLEANing depth and the undeconvolved sources outside the field-of-view. We show that we can approach the theoretical noise limit using a more efficient and automated CLEAN algorithm.
Organizations are undergoing unprecedented transformation in the area of talent management (TM). Companies are rapidly adopting new tools and approaches in a variety of what has traditionally been core areas of industrial and organizational (I-O) psychology such as performance management, employee attitudes, recruiting, testing and assessment, and career development. Increasingly, however, these new approaches have little to no research backing behind them, and they do not tend to be the focus of I-O psychology theory and research. We call this trend anti-industrial and organizational psychology (AIO), as we believe these forces to do not advance the field for long-term strategic impact. We present a framework that describes how AIO practices are adopted by organizations, and how I-O psychologists often gravitate away from these practices rather than actively help to separate the wheat from the chaff. We found support for our hypothesis through a brief analysis of Industrial and Organizational Psychology: Perspectives on Science and Practice, the peer-reviewed journal of the Society of Industrial and Organizational Psychology (SIOP). In this analysis, we found that only 10% of the focal articles from 2008 to 2016 represented topics that we call frontier—emerging areas in organizations but where there is no research support for them. We propose a set of recommendations for the field of I-O psychology and call for a more strategic approach to identifying and vetting new TM trends in order to increase the relevancy and impact of I-O psychology for our key stakeholders.
The Evolutionary Map of the Universe (EMU) is a proposed radio continuum survey
of the Southern Hemisphere up to declination + 30°, with the Australian
Square Kilometre Array Pathfinder (ASKAP). EMU will use an automated source
identification and measurement approach that is demonstrably optimal, to
maximise the reliability and robustness of the resulting radio source
catalogues. As a step toward this goal we conducted a “Data
Challenge” to test a variety of source finders on simulated images. The
aim is to quantify the accuracy and limitations of existing automated source
finding and measurement approaches. The Challenge initiators also tested the
current ASKAPsoft source-finding tool to establish how it could benefit from
incorporating successful features of the other tools. As expected, most finders
show completeness around 100% at ≈ 10σ dropping to about 10% by
≈ 5σ. Reliability is typically close to 100% at ≈
10σ, with performance to lower sensitivities varying between finders. All
finders show the expected trade-off, where a high completeness at low
signal-to-noise gives a corresponding reduction in reliability, and vice versa.
We conclude with a series of recommendations for improving the performance of
the ASKAPsoft source-finding tool.
To review the literature on the outcomes of ENT operations in order to assess whether ENT operations are effective.
The value of evidence-based medicine in relation to ENT was appraised, as was the perception of effectiveness. Literature on common ENT operations, including grommet insertion, tonsillectomy and adenoidectomy, and correction of the nasal septum, was evaluated.
Results and conclusion:
When evaluating the effectiveness of ENT operations, the patient's overall condition and improvements after surgery should be measured. Objective and subjective factors should both be considered as good evidence, especially with the increasing role that evidence-based medicine plays in decisions of whether to operate. The literature review provides evidence that ENT operations are effective.
EMU is a wide-field radio continuum survey planned for the new Australian Square Kilometre Array Pathfinder (ASKAP) telescope. The primary goal of EMU is to make a deep (rms ∼ 10 μJy/beam) radio continuum survey of the entire Southern sky at 1.3 GHz, extending as far North as +30° declination, with a resolution of 10 arcsec. EMU is expected to detect and catalogue about 70 million galaxies, including typical star-forming galaxies up to z ∼ 1, powerful starbursts to even greater redshifts, and active galactic nuclei to the edge of the visible Universe. It will undoubtedly discover new classes of object. This paper defines the science goals and parameters of the survey, and describes the development of techniques necessary to maximise the science return from EMU.
The FASTer-lite model is multi-compartmental model that can be used to simulate transfer through a simple terrestrial food-chain. The model uses allometric relationships to describe dietary intake rates and radionuclide biological half-lives; the latter were mostly derived from published literature. This type of conventional modelling, for simulating the transfer of radionuclides to representative animals such as birds, results in the observation that activity concentrations associated with ecological compartments approach an equilibrium after a certain time interval. Whilst this approach has validity, however, it is not biologically plausible as it ignores reproduction. In this study we calculate how activity concentrations may vary if transfer to eggs and subsequent growth dilution occurring within juvenile birds is accounted for.
Alternative energy sources such as thin film photovoltaics can be accelerated by improving the rapid and successful transition from laboratory research innovation to commercial production. Most laboratory research and development is on a small scale and its production is in small volumes. It focuses on exploration, discovery, and understanding. When the successful innovation is commercialized, both the scale and the volume increase dramatically and the focus shifts to performance, reliability, yield and cost. This transformation can be accelerated by closely managing risk and by integrating the equipment design and the process development. Also, the cadmium telluride photovoltaic technology has properties that make it more amenable to rapid scale up to low cost and high volume manufacturing.
We present the results of a comprehensive Spitzer survey of 70 radio galaxies across 1 < z < 5.2. Using IRAC (3.6–8.0μm), IRS (16 μm) and MIPS (24–160 μm) imaging, we decompose the rest-frame optical to infrared spectral energy distributions into stellar, AGN, and dust components and determine the contribution of host galaxy stellar emission at rest-frame 1.6 μm (H-band). We find that the fraction of emitted light at rest-frame 1.6 μm from stars is >80% for over half the high redshift radio galaxies. The other radio galaxies have 1.6 μm stellar fractions spanning the range 20–80%. The resultant stellar luminosities imply stellar masses of 1011−12M⊙, independent of redshift, indicating that radio galaxies are amoungst the most massive galaxies observed over this redshift range. Powerful radio galaxies tend to lie in a similar region of mid-IR color-color space as unobscured AGN, despite the inferred stellar contribution to their shorter-wavelength, mid-IR SEDs. The stellar fraction of the rest-frame 1.6 μm luminosity has no correlation with redshift, radio luminosity, or rest-frame mid-IR (5 μm) luminosity. The bolometric energy output of these sources is dominated by the infrared, and the mid-IR luminosities are found to be similar to that of lower redshift (z < 1) radio galaxies. As expected, these exceptionally high mid-IR luminosities are consistent with an obscured, highly-accreting AGN. A weak, but significant, correlation of stellar mass with radio luminosity is found, consistent with earlier results.
Lemierre's syndrome is characterized by acute oropharyngeal infection complicated by internal jugular venous thrombosis secondary to septic thrombophlebitis, and metastatic abscesses. We report a case of Lemierre's syndrome in an 18-year-old Caucasian woman presenting with a peritonsillar abscess and ipsilateral VIth cranial nerve palsy.
Locomotion of the box jellyfish Chiropsalmus sp. (cf quadrigatus)1 (Haeckel) and Chironex fleckeri (Southcott) was analysed using digital video. Specimens of Chiropsalmus sp. and C. fleckeri were collected in 2001 and 2002, respectively, from coastal waters of Northern Queensland, Australia. Chiropsalmus sp. animals were videoed swimming in an aquarium, and C. fleckeri in a large outdoor tank. Locomotor sequences of nine Chiropsalmus sp. and seven C. fleckeri individuals were analysed using video techniques. A subset of animals had fluorescent dye injected into the sub-umbrellar cavity, to allow observation of water movements during ejection from the bell. Both species used an intermittent style of jet propulsion similar to that documented for some other species of cubozoan medusae. Computer analysis allowed examination of positions of bell parts over time intervals (0.04 s) by comparing coordinates of nodes marked on various bell parts using imaging software. Examination of node coordinates allowed a detailed qualitative description of gait, in addition to quantitative statistical analyses. General linear modelling showed that interspecific differences in locomotion were explicable in terms of body size. Larger animals of both species tended to swim faster, and with a lower pulse frequency, than smaller individuals. Smaller animals also tended to swim faster relative to their bell diameter.
In this paper our current knowledge of the mechanisms underlying the induction of bystander effects by low dose low LET ionizing radiation is reviewed in the context of relevance to radiation protection issues. The question of how bystander effects may be related to observed adaptive responses, systemic genomic instability or other effects of low doses exposures is also considered. Bystander effects appear to be the result of a generalized stress response in tissues or cells. The signals may be produced by all exposed cells, but the response may require additional system parameters to exist in order to be expressed. The major response involving low LET radiation exposure discussed in the existing literature is a death response. This can manifest as apoptotic cell death, terminal differentiation, reproductive cell death or necrosis. While a death response might appear to be adverse, the position is argued in this paper, that it can in fact be protective and remove damaged cells from the reproducing population. Since many cell populations carry damaged cells without being exposed to radiation (so-called “background damage”), it is possible that low dose radiation exposures cause removal of cells damaged by agents other than the test dose of radiation. This mechanism would lead to the production of “u- or n-shaped” dose response curves. In this scenario, the level of harmful or beneficial response will be related to the background damage carried by the cell population and the genetic program determining response to damage. This model may be particularly important when attempting to predict the consequences of mixed exposures involving radiation and other environmental stressors on biota.
The Namib Desert golden mole (Eremitalpa granti namibensis) is a small (c. 20 g), blind, sand-swimming, chrysochlorid insectivore that inhabits the sand dunes of one of the driest and least productive areas of the world. Its food, largely termites, is sparse and occurs in widely distributed patches, and free water is unavailable. The moles forage by running on the surface and burrowing below the sand. We estimated their daily energy expenditure in the field to be 11.8 kJ d-1 by constructing a ‘distance-energy budget’ based on measurements of tracks in the sand and the energy cost of running (4.2 kJ d-1), burrowing (3.2 kJ d-1), and resting (4.4 kJ d-1). We also measured field metabolic rate (12.5 kJ d-1) and water turnover (2.3 ml d-1) independently with doubly-labelled water. The resting metabolic rate (0.5 ml O2 g-1 h-1 at 35 °C) is about a fifth of that predicted for a normal insectivorous mammal, and the daily field energy expenditure and water turnover are about a half. The low daily energy expenditure stems mainly from the low resting metabolic rate, which is associated with low body temperatures and metabolic depression. Moles save more energy during foraging by running on the surface of the sand, rather than burrowing under it. The gross energy cost of sand-swimming (80 J m-1) is 26 times more expensive than running on the surface (3.0 J m-1), but is less than a tenth of the energy required by mammals that tunnel through compact soil. Nevertheless, it would be energetically impossible for the moles to obtain enough food by foraging only underground at our study site. The mean track length was 1.4 km, but only 16 m of it was below the surface. There is evidence that the track length and fraction underground depend on food abundance which is influenced by rainfall.
Wilson's disease (WD) is an autosomal recessive disorder of copper metabolism with an incidence of about 30 per million (i.e. fewer than 2,000 in the UK). Nevertheless, it is important for two main reasons: its manifestations are protean and may lead it to present to a range of specialists; and its otherwise lethal course can be halted by treatment with chelating agents such as penicillamine and trientine. Published cases and systematic study have shown that neuropsychiatric symptomatology is important in a high proportion. In fact, about one-fifth either present psychiatrically or are at least seen by a psychiatrist before WD is diagnosed.
1.1. Section 78 of the Insurance Companies Act 1974 makes provision for Regulations to be made for the valuation of assets and liabilities. Regulations relating to the valuation of assets, although not published at the time of writing, are expected to be laid before Parliament in the near future.
It is expected that the corresponding Regulations for the valuation of liabilities will be issued later in 1975.
1.2. The Department of Trade has consulted interested bodies, including the Faculty and the Institute, with regard to proposals for the content of the Valuation of Liabilities Regulations and with its permission part of the relevant Consultative Note is reproduced in Appendix I.
The Authors are members of a Working Party established by the Councils of the Faculty and Institute to consider the Department of Trade's proposed Rules for valuing the liabilities of long-term business.
The paper opens with a short introduction followed by Part 2 which considers the control systems operating in several overseas territories. Part 3 is largely historical and traces the development of actuarial thought and practice since the war. The negotiations in Europe are also covered. Having set the scene, the Authors move to consideration of the Department of Trade's proposals (the proposed Rules for valuation of liabilities are included as an Appendix to the Paper). After a brief description of the proposed Asset Value Regulations in Part 4 the net premium valuation method is discussed in Part 5 and the problems of large fluctuations in the interest basis are illustrated by examples. Possible modifications to the conventional formula are explored with further examples. The elements of the valuation basis are discussed in turn with particular emphasis on the valuation rate of interest.
The Authors conclude that the problems arising from use of high rates of interest in valuation are not so much a function of the inadequacy of the valuation method as an indication of the real financial strains to which offices are exposed in current conditions. The paper ends with a reminder that with the varied traditions of the British market no one set of Valuation Rules can satisfactorily cover every special case. Any statutory basis therefore must be seen as a compromise, and the Authors touch on special cases where they feel that it would be appropriate for the authorities to exercise their discretionary powers.