Evidence of Particle Acceleration in the Superbubble 30 Doradus C with NuSTAR

We present evidence of diffuse, non-thermal X-ray emission from the superbubble 30 Doradus C (30 Dor C) using hard X-ray images and spectra from NuSTAR observations. For this analysis, we utilize data from a 200 ks targeted observation of 30 Dor C as well as 2.8 Ms of serendipitous off-axis observations from the monitoring of nearby SN 1987A. The complete shell of 30 Dor C is detected up to 20 keV, and the young supernova remnant MCSNR J0536-6913 in the southeast of 30 Dor C is not detected above 8 keV. Additionally, six point sources identified in previous Chandra and XMM-Newton investigations have hard X-ray emission coincident with their locations. Joint spectral fits to the NuSTAR and XMM-Newton spectra across the 30 Dor C shell confirm the non-thermal nature of the diffuse emission. Given the best-fit rolloff frequencies of the X-ray spectra, we find maximum electron energies of 70-110 TeV (assuming a B-field strength of 4$\mu$G), suggesting 30 Dor C is accelerating particles. Particles are either accelerated via diffusive shock acceleration at locations where the shocks have not stalled behind the H$\alpha$ shell, or cosmic-rays are accelerated through repeated acceleration of low-energy particles via turbulence and magnetohydrodynamic waves in the bubble's interior.Comment: 14 pages, 8 figures, ApJ, in pres

Evaluación de los efectos de la urbanización en los arroyos de Tierra del Fuego

We set out to understand how urbanization affects streams in Ushuaia, Tierra del Fuego. Paired ttestsand linear regressions were used to compare physico-chemical stream habitat variables (i.e., temperature,turbidity, conductivity, dissolved oxygen and pH) and benthic macroinvertebrate community structure (i.e.,density, taxonomic richness, Shannon-Weiner diversity) and function (functional feeding groups [FFG]) in fourwatersheds with urban and reference sites. We then calculated indices of biotic integrity for habitat (rapid visualassessment protocol [RVAP]) and benthos (Ephemeroptera, Plecoptera, Trichoptera richness [EPT], family bioticindex [FBI], rapid bioassessment protocol [RBP] and biotic monitoring Patagonian streams [BMPS]). Resultsindicated that urbanization negatively impacted these streams? underlying ecological condition, decreasingbenthic biodiversity and dissolved oxygen, while increasing conductivity and turbidity. FFG assemblagewas similar between both sites, but urbanization increased the existing dominance of collector-gatherers.Additionally, urban sites presented lower values in three of the benthic macroinvertebrate indices (EPT, RBP,BMPS, but not FBI) and also for habitat (RVAP). These data fill an existing gap in stream ecology for southernPatagonia and are useful to create monitoring tools. By incorporating urbanization as a driver of ecosystemchange, managers and planners will be better able to confront the issue of sustainable development in thisregion, which is considered one of the most pristine wilderness areas remaining on the planet but whosehuman population is concentrated in a few densely populated urban areas.Fil: Zagarola, Jean Paul A.. Bonneville Environmental Foundation; Estados UnidosFil: Martínez Pastur, Guillermo José. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Lopez, María Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Anderson, Christopher Brian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentin

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

Orthogonal-view Microscope for the Biomechanics Investigations of Aquatic Organisms

Microscopes are essential for biomechanics and hydrodynamical investigation of small aquatic organisms. We report a DIY microscope (GLUBscope) that enables the visualization of organisms from two orthogonal imaging planes (top and side views). Compared to conventional imaging systems, this approach provides a comprehensive visualization strategy of organisms, which could have complex shapes and morphologies. The microscope was constructed by combining custom 3D-printed parts and off-the-shelf components. The system is designed for modularity and reconfigurability. Open-source design files and build instructions are provided in this report. Additionally, proof of use experiments, particularly with Hydra and other organisms that combine the GLUBscope with an analysis pipeline, were demonstrated. Beyond the applications demonstrated, the system can be used or modified for various imaging applications

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

Physician Clinical Alignment and Integration: A Community Academic Hospital Approach

An overwhelming need for change in the U.S. healthcare delivery system, coupled with the need to improve clinical and financial outcomes, has prompted hospitals to direct renewed efforts toward achieving high quality and cost-effectiveness. Additionally, with the dawn of accountable care organizations and increasing focus on patient expectations, hospitals have begun to seek physician partners through clinical alignment. Contrary to the unsuccessful alignment strategies of the 1990s, today\u27s efforts are more mutually beneficial, driven by the need to achieve better care coordination, increased access to infrastructure, improved quality, and lower costs. In this article, we describe a large, academic, tertiary care hospital\u27s approach to developing and implementing alignment and integration models with its collaboration-ready physicians and physician groups. We developed four models--short of physicians\u27 employment with the organization--tailored to meet the needs of both the physician group and the hospital: (1) medical directorship (group physicians are appointed to serve as medical directors of a clinical area), (2) professional services agreement (specific clinical services, such as overnight admissions help, are contracted), (3) co-management services agreement (one specialty group co-manages all services within the specialty service lines), and (4) lease arrangement (closest in scope to employment, in which the hospital pays all expenses and receives all revenue). Successful hospital-physician alignment requires careful planning and the early engagement of legal counsel to ensure compliance with federal statutes. Establishing an integrated system with mutually identified goals better positions hospitals to deliver cost-effective and high-quality care under the new paradigm of healthcare reform