The Tanzanian Trauma patients' Prehospital Experience: A Qualitative Interview-based Study.

We sought to characterise the prehospital experience of Tanzanian trauma patients, and identify barriers and facilitators to implement community-based emergency medical systems (EMS). Our study was conducted in the emergency department of an urban national referral hospital in Tanzania. A convenience sample of 34 adult trauma patients, or surrogate family members, presenting or referred to an urban referral emergency department in Tanzania for treatment of injury, participated in the study. Participation in semistructured, iteratively developed interviews until saturation of responses was reached. A grounded theory-based approach to qualitative analysis was used to identify recurrent themes. We characterised numerous deficiencies within the existing clinic-to-hospital referral network, including missed/delayed diagnoses, limited management capabilities at pre-referral facilities and interfacility transfer delays. Potential barriers to EMS implementation include patient financial limitations and lack of insurance, limited public infrastructure and resources, and the credibility of potential first aid responders. Potential facilitators of EMS include communities' tendency to pool resources, individuals' trust of other community members to be first aid responders, and faith in community leaders to organise EMS response. Participants expressed a strong desire to learn first aid. The composite themes generated by the data suggest that there are myriad structural, financial, institutional and cultural barriers to the implementation of a formal prehospital system. However, our analysis also revealed potential facilitators to a first-responder system that takes advantage of close-knit local communities and the trust of recognised leaders in society. The results suggest favourable acceptability for community-based response by trained lay people. There is significant opportunity for care improvements with short trainings and low-cost supply planning. Further research looking at the effects of delay on outcomes in this population is needed

A Spatially Resolved Study of the Synchrotron Emission and Titanium in Tycho's Supernova Remnant with NuSTAR

We report results from deep observations (~750 ks) of Tycho's supernova remnant (SNR) with NuSTAR. Using these data, we produce narrow-band images over several energy bands to identify the regions producing the hardest X-rays and to search for radioactive decay line emission from 44Ti. We find that the hardest (>10 keV) X-rays are concentrated in the southwest of Tycho, where recent Chandra observations have revealed high emissivity "stripes" associated with particles accelerated to the knee of the cosmic-ray spectrum. We do not find evidence of 44Ti, and we set limits on its presence and distribution within the SNR. These limits correspond to a upper-limit 44Ti mass of M44 < 2.4x10^-4 M_sun for a distance of 2.3 kpc. We perform spatially resolved spectroscopic analysis of sixty-six regions across Tycho. We map the best-fit rolloff frequency of the hard X-ray spectra, and we compare these results to measurements of the shock expansion and ambient density. We find that the highest energy electrons are accelerated at the lowest densities and in the fastest shocks, with a steep dependence of the roll-off frequency with shock velocity. Such a dependence is predicted by models where the maximum energy of accelerated electrons is limited by the age of the SNR rather than by synchrotron losses, but this scenario requires far lower magnetic field strengths than those derived from observations in Tycho. One way to reconcile these discrepant findings is through shock obliquity effects, and future observational work is necessary to explore the role of obliquity in the particle acceleration process.Comment: 12 pages, 12 figures, ApJ in pres

The Hard X-Ray View of the Young Supernova Remnant G1.9+0.3

NuSTAR observed G1.9+0.3, the youngest known supernova remnant in the Milky Way, for 350 ks and detected emission up to $\sim$30 keV. The remnant's X-ray morphology does not change significantly across the energy range from 3 to 20 keV. A combined fit between NuSTAR and CHANDRA shows that the spectrum steepens with energy. The spectral shape can be well fitted with synchrotron emission from a power-law electron energy distribution with an exponential cutoff with no additional features. It can also be described by a purely phenomenological model such as a broken power-law or a power-law with an exponential cutoff, though these descriptions lack physical motivation. Using a fixed radio flux at 1 GHz of 1.17 Jy for the synchrotron model, we get a column density of N$_{\rm H}$ = $(7.23\pm0.07) \times 10^{22}$ cm$^{-2}$, a spectral index of $\alpha=0.633\pm0.003$, and a roll-off frequency of $\nu_{\rm rolloff}=(3.07\pm0.18) \times 10^{17}$ Hz. This can be explained by particle acceleration, to a maximum energy set by the finite remnant age, in a magnetic field of about 10 $\mu$G, for which our roll-off implies a maximum energy of about 100 TeV for both electrons and ions. Much higher magnetic-field strengths would produce an electron spectrum that was cut off by radiative losses, giving a much higher roll-off frequency that is independent of magnetic-field strength. In this case, ions could be accelerated to much higher energies. A search for $^{44}$Ti emission in the 67.9 keV line results in an upper limit of $1.5 \times 10^{-5}$ $\,\mathrm{ph}\,\mathrm{cm}^{-2}\,\mathrm{s}^{-1}$ assuming a line width of 4.0 keV (1 sigma).Comment: 9 pages, 6 figures, accepted Ap

High-Energy X-ray Imaging of the Pulsar Wind Nebula MSH~15-52: Constraints on Particle Acceleration and Transport

We present the first images of the pulsar wind nebula (PWN) MSH 15-52 in the hard X-ray band (>8 keV), as measured with the Nuclear Spectroscopic Telescope Array (NuSTAR). Overall, the morphology of the PWN as measured by NuSTAR in the 3-7 keV band is similar to that seen in Chandra high-resolution imaging. However, the spatial extent decreases with energy, which we attribute to synchrotron energy losses as the particles move away from the shock. The hard-band maps show a relative deficit of counts in the northern region towards the RCW 89 thermal remnant, with significant asymmetry. We find that the integrated PWN spectra measured with NuSTAR and Chandra suggest that there is a spectral break at 6 keV which may be explained by a break in the synchrotron-emitting electron distribution at ~200 TeV and/or imperfect cross calibration. We also measure spatially resolved spectra, showing that the spectrum of the PWN softens away from the central pulsar B1509-58, and that there exists a roughly sinusoidal variation of spectral hardness in the azimuthal direction. We discuss the results using particle flow models. We find non-monotonic structure in the variation with distance of spectral hardness within 50" of the pulsar moving in the jet direction, which may imply particle and magnetic-field compression by magnetic hoop stress as previously suggested for this source. We also present 2-D maps of spectral parameters and find an interesting shell-like structure in the NH map. We discuss possible origins of the shell-like structure and their implications.Comment: 15 pages, 9 figures, accepted for publication in Ap

Mobilizing Minds: Integrated knowledge translation and youth engagement in the development of mental health information resources

High rates of highly persistent mental health problems can have significantly damaging effects on young adults’ lives, and young adults are less likely to seek treatment for such problems. This article describes a unique Canadian knowledge translation project called Mobilizing Minds: Pathways to Young Adult Mental Health, which aimed to impact not only the mental health literacy of young adults, but to engage young adults in the entire research process from inception to dissemination of results. Knowledge translation is a process that involves producing and assessing the quality of the knowledge to be translated and tailoring the knowledge to be user friendly for particular segments of the population. The article gives particular attention to the ways in which the Mobilizing Minds project was influenced by youth engagement. We discuss three aspects: 1) structures, processes and communication; 2) project products; and 3) challenges and responses. Lessons learned specific to intergenerational collaboration will be of interest to youth as consumers of mental health information and services, mental health practitioners, researchers, and decision-makers seeking to improve mental health at a systemic level.Keywords: knowledge translation, young adult, mental health, participatory research, youth engagement, youth-adult partnership

NuSTAR study of Hard X-Ray Morphology and Spectroscopy of PWN G21.5-0.9

We present NuSTAR high energy X-ray observations of the pulsar wind nebula (PWN)/supernova remnant G21.5-0.9. We detect integrated emission from the nebula up to ~40 keV, and resolve individual spatial features over a broad X-ray band for the first time. The morphology seen by NuSTAR agrees well with that seen by XMM-Newton and Chandra below 10 keV. At high energies NuSTAR clearly detects non-thermal emission up to ~20 keV that extends along the eastern and northern rim of the supernova shell. The broadband images clearly demonstrate that X-ray emission from the North Spur and Eastern Limb results predominantly from non-thermal processes. We detect a break in the spatially integrated X-ray spectrum at ~9 keV that cannot be reproduced by current SED models, implying either a more complex electron injection spectrum or an additional process such as diffusion compared to what has been considered in previous work. We use spatially resolved maps to derive an energy-dependent cooling length scale, $L(E) \propto E^{m}$ with $m = -0.21 \pm 0.01$. We find this to be inconsistent with the model for the morphological evolution with energy described by Kennel & Coroniti (1984). This value, along with the observed steepening in power-law index between radio and X-ray, can be quantitatively explained as an energy-loss spectral break in the simple scaling model of Reynolds (2009), assuming particle advection dominates over diffusion. This interpretation requires a substantial departure from spherical magnetohydrodynamic (MHD), magnetic-flux-conserving outflow, most plausibly in the form of turbulent magnetic-field amplification.Comment: 13 pages, 8 figures, 1 table, Accepted for publication in the Astrophysical Journa

Locating the most energetic electrons in Cassiopeia A

We present deep ($>$2.4 Ms) observations of the Cassiopeia A supernova remnant with {\it NuSTAR}, which operates in the 3--79 keV bandpass and is the first instrument capable of spatially resolving the remnant above 15 keV. We find that the emission is not entirely dominated by the forward shock nor by a smooth "bright ring" at the reverse shock. Instead we find that the $>$15 keV emission is dominated by knots near the center of the remnant and dimmer filaments near the remnant's outer rim. These regions are fit with unbroken power-laws in the 15--50 keV bandpass, though the central knots have a steeper ($\Gamma \sim -3.35$) spectrum than the outer filaments ($\Gamma \sim -3.06$). We argue this difference implies that the central knots are located in the 3-D interior of the remnant rather than at the outer rim of the remnant and seen in the center due to projection effects. The morphology of $>$15 keV emission does not follow that of the radio emission nor that of the low energy ($<$12 keV) X-rays, leaving the origin of the $>$15 keV emission as an open mystery. Even at the forward shock front we find less steepening of the spectrum than expected from an exponentially cut off electron distribution with a single cutoff energy. Finally, we find that the GeV emission is not associated with the bright features in the {\it NuSTAR} band while the TeV emission may be, suggesting that both hadronic and leptonic emission mechanisms may be at work.Comment: 12 pages, 11 figures, accepted for publication in Ap

NuSTAR observations of the powerful radio-galaxy Cygnus A

We present NuSTAR observations of the powerful radio galaxy Cygnus A, focusing on the central absorbed active galactic nucleus (AGN). Cygnus A is embedded in a cool-core galaxy cluster, and hence we also examine archival XMM-Newton data to facilitate the decomposition of the spectrum into the AGN and intracluster medium (ICM) components. NuSTAR gives a source-dominated spectrum of the AGN out to >70keV. In gross terms, the NuSTAR spectrum of the AGN has the form of a power law (Gamma~1.6-1.7) absorbed by a neutral column density of N_H~1.6x10^23 cm^-2. However, we also detect curvature in the hard (>10keV) spectrum resulting from reflection by Compton-thick matter out of our line-of-sight to the X-ray source. Compton reflection, possibly from the outer accretion disk or obscuring torus, is required even permitting a high-energy cutoff in the continuum source; the limit on the cutoff energy is E_cut>111keV (90% confidence). Interestingly, the absorbed power-law plus reflection model leaves residuals suggesting the absorption/emission from a fast (15,000-26,000km/s), high column-density (N_W>3x10^23 cm^-2), highly ionized (xi~2,500 erg cm/s) wind. A second, even faster ionized wind component is also suggested by these data. We show that the ionized wind likely carries a significant mass and momentum flux, and may carry sufficient kinetic energy to exercise feedback on the host galaxy. If confirmed, the simultaneous presence of a strong wind and powerful jets in Cygnus A demonstrates that feedback from radio-jets and sub-relativistic winds are not mutually exclusive phases of AGN activity but can occur simultaneously.Comment: 13 pages; accepted for publication in The Astrophysical Journa