457 research outputs found

    Space VLBI at Low Frequencies

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    At sufficiently low frequencies, no ground-based radio array will be able to produce high resolution images while looking through the ionosphere. A space-based array will be needed to explore the objects and processes which dominate the sky at the lowest radio frequencies. An imaging radio interferometer based on a large number of small, inexpensive satellites would be able to track solar radio bursts associated with coronal mass ejections out to the distance of Earth, determine the frequency and duration of early epochs of nonthermal activity in galaxies, and provide unique information about the interstellar medium. This would be a "space-space" VLBI mission, as only baselines between satellites would be used. Angular resolution would be limited only by interstellar and interplanetary scattering.Comment: To appear in "Astrophysical Phenomena Revealed by Space VLBI", ed. H. Hirabayashi, P. Edwards, and D. Murphy (ISAS, Japan

    A One-Health environmental risk assessment of contaminants of emerging concern in London’s waterways throughout the SARS-CoV-2 pandemic

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    The SARS-CoV-2 pandemic had huge impacts on global urban populations, activity and health, yet little is known about attendant consequences for urban river ecosystems. We detected significant changes in occurrence and risks from contaminants of emerging concern (CECs) in waterways across Greater London (UK) during the pandemic. We were able to rapidly identify and monitor large numbers of CECs in n=390 samples across 2019–2021 using novel direct-injection liquid chromatography-mass spectrometry methods for scalable targeted analysis, suspect screening and prioritisation of CEC risks. At total of 10,029 measured environmental concentrations (MECs) were obtained for 66 unique CECs. Pharmaceutical MECs decreased during lockdown in 2020 in the R. Thames (p≤0.001), but then increased significantly in 2021 (p ≤0.01). For the tributary rivers, the R. Lee, Beverley Brook, R. Wandle and R. Hogsmill were the most impacted primarily via wastewater treatment plant effluent and combined sewer overflows. For the R. Hosgmill in particular, pharmaceutical MEC trends were generally correlated with NHS prescription statistics, likely reflecting limited wastewater dilution. Suspect screening of ∼1,200 compounds tentatively identified 25 additional CECs at the five impacted sites, including metabolites such as O-desmethylvenlafaxine, an EU Watch List compound. Lastly, risk quotients (RQs) ≥0.1 were calculated for 21 compounds across the whole Greater London freshwater catchment, of which 7 were of medium risk (RQ ≥1.0) and three were in the high-risk category (RQ ≥10), including imidacloprid (RQ=19.6), azithromycin (15.7) and diclofenac (10.5). This is the largest spatiotemporal dataset of its kind for any major capital city globally and the first for Greater London, representing ∼16 % of the population of England, and delivering a foundational One Health case study in the third largest city in Europe across a global pandemic

    A halo blue straggler on a highly eccentric retrograde orbit

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    Blue straggler, which are stars that appear to be younger than they should be, are an important population of unusual stars in both stellar clusters and the halo field of the Galaxy. Most formation scenarios evoke either stellar collisions or binary stars that transfer mass or merge. We investigate high-velocity stars in the Galactic halo and perform a spectral and kinematical analysis to shed light on their nature and origin. Here we report that SDSSJ130005.62+042201.6 (J1300+0422 for short) is an A-type star of unusually large radial velocity (504.6 ±\pm 5 \kms). From a quantitative NLTE (and LTE) spectral analysis of medium-resolution optical spectra, the elemental composition is derived. Proper motion measurements combined with a spectroscopic distance estimate allow us to determine its present space velocity. Its kinematical properties are derived by integrating the equation of motion in the Galactic potential. We find J1300+0422 to be metal poor ([M/H]=−1.2-1.2) and exhibit an α\alpha-element enrichment (0.3−0.40.3-0.4~dex) that is characteristic of the halo population, as confirmed by a kinematical analysis of its 3D space motions, which places it on a highly eccentric retrograde Galactic orbit. The mass of J1300+0422 (1.15 ±\pm 0.10 M⊙_\odot) is higher than the globular cluster turn-off masses indicating that it is a halo blue straggler star. At a Galactic rest-frame velocity of ≈\approx467~\kms, the star travels faster than any known blue straggler but is still bound to the Galaxy.Comment: 6 pages, 7 figures, accepted for publication in A&

    Planning ahead in Missouri's dairy industry

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    Text of caption on page 6 is cut off due to tight binding."Dairying originated as a way men could turn supplies of forage into profitable human food by applying their skill and labor to the management of herds of milking animals. This objective still applies-but how the means have changed! Methods of getting milk out of a cow, to and through the market, and into the kitchens of consumers have gone from hand style to "untouched by human hand" marvels of mechanization. Even the cow, the factory that does the conversion, has been modified into a manufacturing machine that grows more efficient and productive each year. Average production per cow has climbed from 4,218 to 8,513 pounds per year in the past 40 years. Missouri cows haven't produced as well, but have climbed from 3,300 to 7,400 pounds in the same period. That's one of the problems we need to correct in the next few years to stay in competition. Progress has been slow in increasing forage yields but that's coming in for attention now. This publication reviews where Missouri's dairy industry stands now, where we're headed if present trends continue., and what needs to be done to improve the position of dairying. Ten and 20 years from now we want to be in the forefront."--Page 1.Prepared by O.E. Allen, Edward J. Constien, J.E. Edmondson, Alfred Lane, W.J. Murphy, Leroy Peters, Alva L. Preston, Jr., Edward R. Wiggins, Fred H. Meinershagen (Chairman

    Meaning in hoarding: perspectives of people who hoard on clutter, culture, and agency

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    Hoarding has become increasingly prominent in clinical practice and popular culture in recent years, giving rise to extensive research and commentary. Critical responses in the social sciences have criticised the cultural assumptions built in to the construct of ‘hoarding disorder’ and expressed fears that it may generate stigma outweighing its benefits; however, few of these studies have engaged directly with ‘hoarders’ themselves. This paper reports on in-depth, semi-structured interviews with ten individuals living in England, who received assessment and intervention for hoarding from Social Services. Their narratives drew on the cultural repertoire of values and discourses around waste and worth, the mediation of sociality and relationships through material objects, physical constraints on keeping order, and the role played by mental health. Analysing these perspectives anthropologically shows how dominant models of hoarding, such as the DSM-5 paradigm, potentially lend themselves to reductionist understandings that efface the meaning ‘hoarding’ may have and thereby deny agency to the person labelled as ‘hoarder’. More culturally informed analysis, by contrast, affords insights into the complex landscape of value, waste, social critique, emotion, interpersonal relationships and practical difficulties that may underlie hoarding cases, and points the way to more person-centred practice and analysis

    Comfort radicalism and NEETs: a conservative praxis

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    Young people who are not in education, employment or training (NEET) are construed by policy makers as a pressing problem about which something should be done. Such young people's lack of employment is thought to pose difficulties for wider society in relation to social cohesion and inclusion and it is feared that they will become a 'lost generation'. This paper(1) draws upon English research, seeking to historicise the debate whilst acknowledging that these issues have a much wider purchase. The notion of NEETs rests alongside longstanding concerns of the English state and middle classes, addressing unruly male working class youth as well as the moral turpitude of working class girls. Waged labour and domesticity are seen as a means to integrate such groups into society thereby generating social cohesion. The paper places the debate within it socio-economic context and draws on theorisations of cognitive capitalism, Italian workerism, as well as emerging theories of antiwork to analyse these. It concludes by arguing that ‘radical’ approaches to NEETs that point towards inequities embedded in the social structure and call for social democratic solutions veer towards a form of comfort radicalism. Such approaches leave in place the dominance of capitalist relations as well as productivist orientations that celebrate waged labour

    Solar-like oscillations in red giants observed with Kepler: comparison of global oscillation parameters from different methods

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    The large number of stars for which uninterrupted high-precision photometric timeseries data are being collected with \textit{Kepler} and CoRoT initiated the development of automated methods to analyse the stochastically excited oscillations in main-sequence, subgiant and red-giant stars. Aims: We investigate the differences in results for global oscillation parameters of G and K red-giant stars due to different methods and definitions. We also investigate uncertainties originating from the stochastic nature of the oscillations. Methods: For this investigation we use Kepler data obtained during the first four months of operation. These data have been analysed by different groups using already published methods and the results are compared. We also performed simulations to investigate the uncertainty on the resulting parameters due to different realizations of the stochastic signal. Results: We obtain results for the frequency of maximum oscillation power (nu_max) and the mean large separation () from different methods for over one thousand red-giant stars. The results for these parameters agree within a few percent and seem therefore robust to the different analysis methods and definitions used here. The uncertainties for nu_max and due to differences in realization noise are not negligible and should be taken into account when using these results for stellar modelling.Comment: 11 pages, 9 Figures and 7 tables, accepted for publication in Astronomy and Astrophysic

    s-Process in Low Metallicity Stars. III. Individual analysis of CEMP-s and CEMP-s/r with AGB models

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    We provide an individual analysis of 94 carbon enhanced metal-poor stars showing an s-process enrichment (CEMP-s) collected from the literature. The s-process enhancement observed in these stars is ascribed to mass transfer by stellar winds in a binary system from a more massive companion evolving faster toward the asymptotic giant branch (AGB) phase. The theoretical AGB nucleosynthesis models have been presented in Paper I. Several CEMP-s stars show an enhancement in both s and r-process elements (CEMP-s/r). In order to explain the peculiar abundances observed in CEMP-s/r stars, we assume that the molecular cloud from which CEMP-s formed was previously enriched in r-elements by Supernovae pollution. A general discussion and the method adopted in order to interpret the observations have been provided in Paper II. We present in this paper a detailed study of spectroscopic observations of individual stars. We consider all elements from carbon to bismuth, with particular attention to the three s-process peaks, ls (Y, Zr), hs (La, Nd, Sm) and Pb, and their ratios [hs/ls] and [Pb/hs]. The presence of an initial r-process contribution may be typically evaluated by the [La/Eu] ratio. We found possible agreements between theoretical predictions and spectroscopic data. In general, the observed [Na/Fe] (and [Mg/Fe]) provide information on the AGB initial mass, while [hs/ls] and [Pb/hs] are mainly indicators of the s-process efficiency. A range of 13C-pocket strengths is required to interpret the observations. However, major discrepancies between models and observations exist. We highlight star by star the agreements and the main problems encountered and, when possible, we suggest potential indications for further studies. These discrepancies provide starting points of debate for unsolved problems ...Comment: 40 pages, 54 figures, 3 tables (Appendix A as supplementary material), accepted Monthly Notices of the Royal Astronomical Society, 201

    Vertical integration and firm boundaries : the evidence

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    Since Ronald H. Coase's (1937) seminal paper, a rich set of theories has been developed that deal with firm boundaries in vertical or input–output structures. In the last twenty-five years, empirical evidence that can shed light on those theories also has been accumulating. We review the findings of empirical studies that have addressed two main interrelated questions: First, what types of transactions are best brought within the firm and, second, what are the consequences of vertical integration decisions for economic outcomes such as prices, quantities, investment, and profits. Throughout, we highlight areas of potential cross-fertilization and promising areas for future work
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