Magnetar giant flare high-energy emission

High energy ($> 250$ keV) emission has been detected persisting for several tens of seconds after the initial spike of magnetar giant flares. It has been conjectured that this emission might arise via inverse Compton scattering in a highly extended corona generated by super-Eddington outflows high up in the magnetosphere. In this paper we undertake a detailed examination of this model. We investigate the properties of the required scatterers, and whether the mechanism is consistent with the degree of pulsed emission observed in the tail of the giant flare. We conclude that the mechanism is consistent with current data, although the origin of the scattering population remains an open question. We propose an alternative picture in which the emission is closer to that star and is dominated by synchrotron radiation. The $RHESSI$ observations of the December 2004 flare modestly favor this latter picture. We assess the prospects for the Fermi Gamma-Ray Space Telescope to detect and characterize a similar high energy component in a future giant flare. Such a detection should help to resolve some of the outstanding issues.Comment: 20 pages, 14 figure

Images as catalysts for meaning-making in medical pain encounters: a multidisciplinary analysis

The challenge for those treating or witnessing pain is to find a way of crossing the chasm of meaning between them and the person living with pain. This paper proposes that images can strengthen agency in the person with pain, particularly but not only in the clinical setting, and can create a shared space within which to negotiate meaning. It draws on multidisciplinary analyses of unique material resulting from two fine art/medical collaborations in London, UK, in which the invisible experience of pain was made visible in the form of co-created photographic images, which were then made available to other patients as a resource to use in specialist consultations. In parallel with the pain encounters it describes, the paper weaves together the insights of specialists from a range of disciplines whose methodologies and priorities sometimes conflict and sometimes intersect to make sense of each other’s findings. A short section of video footage where images were used in a pain consultation is examined in fine detail from the perspective of each discipline. The analysis shows how the images function as ‘transactional objects’ and how their use coincides with an increase in the amount of talk and emotional disclosure on the part of the patient and greater non-verbal affiliative behaviour on the part of the doctor. These findings are interpreted from the different disciplinary perspectives, to build a complex picture of the multifaceted, contradictory and paradoxical nature of pain experience, the drive to communicate it and the potential role of visual images in clinical settings

Organised crime and social media; a system for detecting, corroborating and visualising weak signals of organised crime online

This paper describes an approach for detecting the presence or emergence of Organised Crime (OC) signals on Social Media. It shows how words and phrases, used by members of the public in Social Media posts, can be treated as weak signals of OC, enabling information to be classi�ed according to a taxonomy. Formal Concept Analysis (FCA) is used to group information sources, according to Crime-type and Location, thus providing a means of corroboration and creating OC Concepts that can be used to alert police analysts to the possible presence of OC. The analyst is able to `drill down' into an OC Concept of interest, discovering additional information that may be pertinent to the crime. The paper describes the implementation of this approach into a fully-functional prototype software system, incorporating a Social Media scanning system and a map-based user interface. The approach and system are illustrated using Human Tra�cking and Modern Slavery as an example. Real data is used to obtain results that show that weak signals of OC have been detected and corroborated, thus alerting to the possible presence of OC

Eddy-driven subduction exports particulate organic carbon from the spring bloom

The export of particulate organic carbon (POC) from the surface ocean to depth is traditionally ascribed to sinking. Here, we show that a dynamic eddying flow field subducts surface water with high concentrations of nonsinking POC. Autonomous observations made by gliders during the North Atlantic spring bloom reveal anomalous features at depths of 100 to 350 meters with elevated POC, chlorophyll, oxygen, and temperature-salinity characteristics of surface water. High-resolution modeling reveals that during the spring transition, intrusions of POC-rich surface water descend as coherent, 1- to 10-kilometer–scale filamentous features, often along the perimeter of eddies. Such a submesoscale eddy-driven flux of POC is unresolved in global carbon cycle models but can contribute as much as half of the total springtime export of POC from the highly productive subpolar oceans

Organizing to counter terrorism: sensemaking amidst dynamic complexity

publication-status: Acceptedtypes: ArticlePre-print draft (version 1). ‘The final, definitive version of this paper has been published in Human Relations September 2013 66(9): 1201–1223, by SAGE Publications Ltd, All rights reserved. © [The Author]Organizations increasingly find themselves contending with circumstances that are suffused with dynamic complexity. So how do they make sense of and contend with this? Using a sensemaking approach, our empirical case analysis of the shooting of Mr Jean Charles de Menezes shows how sensemaking is tested under such conditions. Through elaborating the relationship between the concepts of frames and cues, we find that the introduction of a new organizational routine to anticipate action in changing circumstances leads to discrepant sensemaking. This reveals how novel routines do not necessarily replace extant ones but instead, overlay each other and give rise to novel, dissonant identities which in turn can lead to an increase in equivocality rather than a reduction. This has important implications for sensemaking and organizing amidst unprecedented circumstances

Cow's Milk Fat Obesity pRevention Trial (CoMFORT): a primary care embedded randomised controlled trial protocol to determine the effect of cow's milk fat on child adiposity.

INTRODUCTION: Cow's milk is a dietary staple for children in North America. Though clinical guidelines suggest children transition from whole (3.25% fat) milk to reduced (1% or 2%) fat milk at age 2 years, recent epidemiological evidence supports a link between whole milk consumption and lower adiposity in children. The purpose of this trial is to determine which milk fat recommendation minimises excess adiposity and optimises child nutrition and growth. METHODS AND ANALYSIS: Cow's Milk Fat Obesity pRevention Trial will be a pragmatic, superiority, parallel group randomised controlled trial involving children receiving routine healthcare aged 2 to 4-5 years who are participating in the TARGet Kids! practice-based research network in Toronto, Canada. Children (n=534) will be randomised to receive one of two interventions: (1) a recommendation to consume whole milk or (2) a recommendation to consume reduced (1%) fat milk. The primary outcome is adiposity measured by body mass index z-score and waist circumference z-score; secondary outcomes will be cognitive development (using the Ages and Stages Questionnaire), vitamin D stores, cardiometabolic health (glucose, high-sensitivity C-reactive protein, non-high density lipoprotein (non-HDL), low density lipoprotein (LDL), triglyceride, HDL and total cholesterol, insulin and diastolic and systolic blood pressure), sugary beverage and total energy intake (measured by 24 hours dietary recall) and cost effectiveness. Outcomes will be measured 24 months postrandomisation and compared using analysis of covariance (ANCOVA), adjusting for baseline measures. ETHICS AND DISSEMINATION: Ethics approval has been obtained from Unity Health Toronto and The Hospital for Sick Children. Results will be presented locally, nationally and internationally and published in a peer-reviewed journal. The findings may be helpful to nutrition guidelines for children in effort to reduce childhood obesity using a simple, inexpensive and scalable cow's milk fat intervention. TRIAL REGISTRATION NUMBER: NCT03914807; pre-results

Luminous Radio Emission from the Superluminous Supernova 2017ens at 3.3 Yr After Explosion

We present the results from a multiyear radio campaign of the superluminous supernova (SLSN) SN 2017ens, which yielded the earliest radio detection of an SLSN to date at the age of ∼3.3 yr after explosion. SN 2017ens was not detected at radio frequencies in the first ∼300 days but reached Lν ≈ 1028 erg s−1 cm−2 Hz−1 at ν ∼ 6 GHz, ∼1250 days post explosion. Interpreting the radio observations in the context of synchrotron radiation from the supernova shock interaction with the circumstellar medium (CSM), we infer an effective mass-loss rate Ṁ ≈ 10−4 M☉ yr−1 at r ∼ 1017 cm from the explosion\u27s site, for a wind speed of vw = 50–60 km s−1 as measured from optical spectra. These findings are consistent with the spectroscopic metamorphosis of SN 2017ens from hydrogen poor to hydrogen rich ∼190 days after explosion reported by Chen et al. SN 2017ens is thus an addition to the sample of hydrogen-poor massive progenitors that explode shortly after having lost their hydrogen envelope. The inferred circumstellar densities, implying a CSM mass up to ∼0.5 M☉, and low velocity of the ejection suggest that binary interactions (in the form of common-envelope evolution and subsequent envelope ejection) play a role in shaping the evolution of the stellar progenitors of SLSNe in the ≲ 500 yr preceding core collapse

Late-Time Radio and Millimeter Observations of Superluminous Supernovae and Long Gamma Ray Bursts: Implications for Obscured Star Formation, Central Engines, and Fast Radio Bursts

We present the largest and deepest late-time radio and millimeter survey to date of superluminous supernovae (SLSNe) and long duration gamma-ray bursts (LGRBs) to search for associated non-thermal synchrotron emission. Using the Karl G. Jansky Very Large Array (VLA) and the Atacama Large Millimeter/submillimeter Array (ALMA), we observed 43 sources at 6 and 100 GHz on a timescale of $\sim 1 - 19$ yr post-explosion. We do not detect radio/mm emission from any of the sources, with the exception of a 6 GHz detection of PTF10hgi (Eftekhari et al. 2019), as well as the detection of 6 GHz emission near the location of the SLSN PTF12dam, which we associate with its host galaxy. We use our data to place constraints on central engine emission due to magnetar wind nebulae and off-axis relativistic jets. We also explore non-relativistic emission from the SN ejecta, and place constraints on obscured star formation in the host galaxies. In addition, we conduct a search for fast radio bursts (FRBs) from some of the sources using VLA Phased-Array observations; no FRBs are detected to a limit of $16$ mJy ($7\sigma$; 10 ms duration) in about 40 min on source per event. A comparison to theoretical models suggests that continued radio monitoring may lead to detections of persistent radio emission on timescales of $\gtrsim {\rm decade}$.Comment: 30 pages; 12 figures; accepted to Ap

SN 2020zbf: A fast-rising hydrogen-poor superluminous supernova with strong carbon lines

SN 2020zbf is a hydrogen-poor superluminous supernova at $z = 0.1947$ that shows conspicuous C II features at early times, in contrast to the majority of H-poor SLSNe. Its peak magnitude is $M_{\rm g}$ = $-21.2$ mag and its rise time ($\lesssim 24$ days from first light) place SN 2020zbf among the fastest rising SLSNe-I. Spectra taken from ultraviolet (UV) to near-infrared wavelengths are used for the identification of spectral features. We pay particular attention to the C II lines as they present distinctive characteristics when compared to other events. We also analyze UV and optical photometric data, and model the light curves considering three different powering mechanisms: radioactive decay of Ni, magnetar spin-down and circumstellar material interaction (CSM). The spectra of SN 2020zbf match well with the model spectra of a C-rich low-mass magnetar model. This is consistent with our light curve modelling which supports a magnetar-powered explosion with a $M_{\rm ej}$ = 1.5 $M_\odot$. However, we cannot discard the CSM-interaction model as it also may reproduce the observed features. The interaction with H-poor, carbon-oxygen CSM near peak could explain the presence of C II emission lines. A short plateau in the light curve, around 30 - 40 days after peak, in combination with the presence of an emission line at 6580 \r{A} can also be interpreted as late interaction with an extended H-rich CSM. Both the magnetar and CSM interaction models of SN 2020zbf indicate that the progenitor mass at the time of explosion is between 2 - 5 $M_\odot$. Modelling the spectral energy distribution of the host reveals a host mass of 10$^{8.7}$ $M_\odot$, a star-formation rate of 0.24$^{+0.41}_{-0.12}$ $M_\odot$ yr$^{-1}$ and a metallicity of $\sim$ 0.4 $Z_\odot$.Comment: 26 pages, 22 figures, submitted to A&