2,591 research outputs found

    Large-Scale Image Processing with the ROTSE Pipeline for Follow-Up of Gravitational Wave Events

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    Electromagnetic (EM) observations of gravitational-wave (GW) sources would bring unique insights into a source which are not available from either channel alone. However EM follow-up of GW events presents new challenges. GW events will have large sky error regions, on the order of 10-100 square degrees, which can be made up of many disjoint patches. When searching such large areas there is potential contamination by EM transients unrelated to the GW event. Furthermore, the characteristics of possible EM counterparts to GW events are also uncertain. It is therefore desirable to be able to assess the statistical significance of a candidate EM counterpart, which can only be done by performing background studies of large data sets. Current image processing pipelines such as that used by ROTSE are not usually optimised for large-scale processing. We have automated the ROTSE image analysis, and supplemented it with a post-processing unit for candidate validation and classification. We also propose a simple ad hoc statistic for ranking candidates as more likely to be associated with the GW trigger. We demonstrate the performance of the automated pipeline and ranking statistic using archival ROTSE data. EM candidates from a randomly selected set of images are compared to a background estimated from the analysis of 102 additional sets of archival images. The pipeline's detection efficiency is computed empirically by re-analysis of the images after adding simulated optical transients that follow typical light curves for gamma-ray burst afterglows and kilonovae. We show that the automated pipeline rejects most background events and is sensitive to simulated transients to limiting magnitudes consistent with the limiting magnitude of the images

    Introduction:Conceptualizing Hinterlands

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    This introduction first considers the history of the hinterland as not just any spatial distribution but one driven by and instrumental to the workings of the capitalist-colonialist-climatic assemblage. Subsequently, it contends that an interdisciplinary conceptual approach to hinterlands that straddles the humanities and social sciences allows for critical and engaged reflection on the haunting afterlives of colonialism, the logistical turn of global capitalism, the impending threat of environmental collapse, and persistent urban-suburban-rural-wilderness divides. The introduction closes by outlining how, together, the contributions to this volume make clear that while hinterlands are primarily realms of extraction and abandonment, they are places of possibility as well, where alternative ways of living together and new forms of care, including for the planet, may flourish

    Testing whether barriers to a hypothetical screening test affect unrelated perceived benefits and vice versa: A randomised, experimental study

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    OBJECTIVE: Determine whether (fictitious) health screening test benefits affect perceptions of (unrelated) barriers, and barriers affect perceptions of benefits. METHODS: UK adults were recruited via an online survey panel and randomised to receive a vignette describing a hypothetical screening test with either high or low benefits (higher vs. lower mortality reduction) and high or low barriers (severe vs. mild side-effects; a 2Ɨ2 factorial design). ANOVAs compared mean perceived benefits and barriers scores. Screening 'intentions' were compared using Pearson's Ļ‡(2) test. RESULTS: Benefits were rated less favourably when barriers were high (mean: 27.4, standard deviation: 5.3) than when they were low (M: 28.5, SD: 4.8; p=0.010, partial Ī·(2)=0.031). Barriers were rated more negatively when benefits were low (M: 17.1, SD: 7.6) than when they were high (M: 15.7, SD: 7.3; p=0.023, partial Ī·(2)=0.024). Most intended to have the test in all conditions (73-81%); except for the low benefit-high barrier condition (37%; p<0.0005; N=218). CONCLUSIONS: Perceptions of test attributes may be influenced by unrelated characteristics. PRACTICE IMPLICATIONS: Reducing screening test barriers alone may have suboptimal effects on perceptions of barriers if benefits remain low; increasing screening benefits may not improve perceptions of benefits if barriers remain high

    Farnesyl diphosphate synthase, the target for nitrogen-containing bisphosphonate drugs, is a peroxisomal enzyme in the model system Dictyostelium discoideum

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    NBP (nitrogen-containing bisphosphonate) drugs protect against excessive osteoclast-mediated bone resorption. After binding to bone mineral, they are taken up selectively by the osteoclasts and inhibit the essential enzyme FDPS (farnesyl diphosphate synthase). NBPs inhibit also growth of amoebae of Dictyostelium discoideum in which their target is again FDPS. A fusion protein between FDPS and GFP (green fluorescent protein) was found, in D. discoideum, to localize to peroxisomes and to confer resistance to the NBP alendronate. GFP was also directed to peroxisomes by a fragment of FDPS comprising amino acids 1ā€“22. This contains a sequence of nine amino acids that closely resembles the nonapeptide PTS2 (peroxisomal targeting signal type 2): there is only a single amino acid mismatch between the two sequences. Mutation analysis confirmed that the atypical PTS2 directs FDPS into peroxisomes. Furthermore, expression of the D. discoideum FDPSā€“GFP fusion protein in strains of Saccharomyces cerevisiae defective in peroxisomal protein import demonstrated that import of FDPS into peroxisomes was blocked in a strain lacking the PTS2-dependent import pathway. The peroxisomal location of FDPS in D. discoideum indicates that NBPs have to cross the peroxisomal membrane before they can bind to their target

    Motor imagery of speech:the involvement of primary motor cortex in manual and articulatory motor imagery

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    Motor imagery refers to the phenomenon of imagining performing an action without action execution. Motor imagery and motor execution are assumed to share a similar underlying neural system that involves primary motor cortex (M1). Previous studies have focused on motor imagery of manual actions, but articulatory motor imagery has not been investigated. In this study, transcranial magnetic stimulation (TMS) was used to elicit motor-evoked potentials (MEPs) from the articulatory muscles [orbicularis oris (OO)] as well as from hand muscles [first dorsal interosseous (FDI)]. Twenty participants were asked to execute or imagine performing a simple squeezing task involving a pair of tweezers, which was comparable across both effectors. MEPs were elicited at six time points (50, 150, 250, 350, 450, 550 ms post-stimulus) to track the time course of M1 involvement in both lip and hand tasks. The results showed increased MEP amplitudes for action execution compared to rest for both effectors at time points 350, 450 and 550 ms, but we found no evidence of increased cortical activation for motor imagery. The results indicate that motor imagery does not involve M1 for simple tasks for manual or articulatory muscles. The results have implications for models of mental imagery of simple articulatory gestures, in that no evidence is found for somatotopic activation of lip muscles in sub-phonemic contexts during motor imagery of such tasks, suggesting that motor simulation of relatively simple actions does not involve M1

    Fine-Tuning Reception in the Bone: PPARĪ³ and Company

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    PPARĪ³ plays a central role in the formation of fat. Regulation of PPARĪ³ activity depends on numerous factors ranging from dietary ligands to nuclear hormone coactivators and corepressors to oxygen-sensing mechanisms. In addition, the interplay of PPARĪ³ with other nuclear hormone receptors has implications for the balance between adipogenesis and osteogenesis in mesenchymal stem cells of the bone marrow stroma. This review will explore a range of factors influencing PPARĪ³ activity and how these interactions may affect osteogenesis
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