2,014 research outputs found
Analysis of the Very Inner Milky Way Dark Matter Distribution and Gamma-Ray Signals
We analyze the possibility that the HESS gamma-ray source at the Galactic
Center could be explained as the secondary flux produced by annihilation of TeV
Dark Matter (TeVDM) particles with locally enhanced density, in a region
spatially compatible with the HESS observations themselves. We study the inner
100 pc considering (i) the extrapolation of several density profiles from
state-of-the-art N-body + Hydrodynamics simulations of Milky Way-like galaxies,
(ii) the DM spike induced by the black hole, and (iii) the DM particles
scattering off by bulge stars. We show that in some cases the DM spike may
provide the enhancement in the flux required to explain the cut-off in the HESS
J1745-290 gamma-ray spectra as TeVDM. In other cases, it may helps to describe
the spatial tail reported by HESS II at angular scales < 0.54 degrees towards
Sgr A.Comment: 6 pages, 3 figures, 1 table. Accepted for publication in Physical
Review D - Rapid Communication
Hot Electron Bolometer Development for a Submillimeter Heterodyne Array Camera
We are developing Nb diffusion-cooled Hot Electron Bolometers (HEBs) for a
large-format array submillimeter camera. We have fabricated Nb HEBs using a new
angle deposition process. We have characterized these devices using heterodyne
mixing at 20 GHz. We also report on optimizations in the fabrication process
that improve device performance.Comment: 2005 International Symposium on Space Terahertz Technolog
A brief evidence-based intervention to enhance Workplace Well-being and Flourishing in health care professionals: Feasibility and pilot outcomes
Introduction: The deleterious direct and indirect effects of burnout among physicians and other health care professionals and learners have been well documented. Recently, there have been calls to shift the focus from distress and burnout to enhancing well-being of health care providers and learners. To this end, we developed a brief, well-being focused intervention entitled “CU Flourish” embedded in PERMA theory: positive emotion (P), engagement (E), relationships (R), meaning (M), and accomplishment (A) with a sixth domain – Health – in our working model. Within this framework, elements of values-based interventions, mindful awareness and psychological flexibility inherent to Acceptance and Commitment Therapy were integrated into the appropriate PERMAH domain modules. In this pilot study we examined the effectiveness of CU Flourish in increasing scores of workplace Well-being and Flourishing in a sample of health care professionals and learners.
Methods: Participants (N=20) completed pre-post surveys including validated measures and open-ended questions as part of the program evaluation.
Results: At post-course measurement, participants’ overall PERMAH Workplace Well-being scores, Flourishing Ratio, and Mindfulness scores increased.
Conclusion: Overall, the CU Flourish curriculum may be an effective and desirable intervention for enhancing workplace well-being among health care professionals and learners
Sim Wheel Hand Controls For Disabled Users
The Sim Wheel Hand Controls kit is an open-source project for disabled individuals to experience simulation racing. The project converts a Thrustmaster TX foot pedal set into hand-operated brake and throttle controls. The module uses elements from the pedal set, a 3D printed housing and commonly available hardware. The Do-It-Yourself nature of the project allows the product to be inexpensive and accessible compared to its single competitor. A website was created to share the 3D printing files, detailed instruction manual and resources provided free by the University of Akron. The team found the module to be ergonomic, durable, realistic, and comfortable for several hand sizes of users. Most importantly, this product gives racers the ability to remain competitive against those who are racing by traditional means. This report details the product development process, testing procedures, results and community outreach involved in creating and distributing the Sim Wheel Hand Controls kit
BVRI Surface Photometry of Isolated Spiral Galaxies
A release of multicolor broad band (BVRI) photometry for a subsample of 44
isolated spirals drawn from the Catalogue of Isolated Galaxies (CIG) is
presented. Total magnitudes and colors at various circular apertures, as well
as some global structural/morphological parameters are estimated. Morphology is
reevaluated through optical and sharp/filtered R band images, (B-I) color index
maps, and archive near-IR JHK images from the Two-Micron Survey. The CAS
structural parameters (Concentration, Asymmetry, and Clumpiness) were
calculated from the images in each one of the bands. The fraction of galaxies
with well identified optical/near-IR bars (SB) is 63%, while a 17% more shows
evidence of weak or suspected bars (SAB). The sample average value of the
maximum bar ellipticity is 0.4. Half of the galaxies in the sample shows rings.
We identify two candidates for isolated galaxies with disturbed morphology. The
structural CAS parameters change with the observed band, and the tendencies
they follow with the morphological type and global color are more evident in
the redder bands. In any band, the major difference between our isolated
spirals and a sample of interacting spirals is revealed in the A-S plane. A
deep and uniformly observed sample of isolated galaxies is intended for various
purposes including (i) comparative studies of environmental effects, (ii)
confronting model predictions of galaxy evolution and (iii) evaluating the
change of galaxy properties with redshift.Comment: 44 pages, 9 figures and 7 tables included. To appear in The
Astronomical Journal. For the 43 appendix figures 4.1-4.43 see
http://www.astroscu.unam.mx/~avila/Figs4.1_4.43.tar.gz (7.2 Mb tar.gz file
Highlights on gamma rays, neutrinos and antiprotons from TeV Dark Matter
We analyze the possibility that the HESS γ-ray source at the Galactic center could be explained as the secondary flux produced by annihilation of TeV dark matter (DM) particles with locally enhanced density, in a region spatially compatible with the HESS observations themselves. We study the inner 100 pc considering (i) the extrapolation of several density profiles from state-of-the-art N-body þ hydrodynamics simulations of Milky Way-like galaxies, (ii) the DM spike induced by the black hole, and (iii) the DM particles scattering off by bulge stars. We show that in some cases the DM spike may provide the enhancement in the flux required to explain the cutoff in the HESS J1745-290γ-ray spectra as TeV DM. In other cases, it may help to describe the spatial tail reported by HESS II at angular scales ≲0.54° toward Sgr A*
Field Tests and Numerical Modeling of Vehicle Impacts on a Boulder Embedded in Compacted Fill
Landscape Vehicular Anti-Ram (LVAR) systems are a group of protective barriers, which are designed using natural materials (e.g., boulders) and have proven to both effectively protect sensitive structures against threats and be aesthetically pleasing. This paper presents two consecutive vehicular crash tests hitting the same single boulder embedded in AASHTO coarse aggregate fill. A LS-DYNA model was developed to simulate the field-scale tests, which were instrumented with high-speed cameras and pressure cells. A readily available truck model from the National Crash Analysis Center was modified and implemented in the LS-DYNA model. The boulder and surrounding soil were modeled using the Mohr-Coulomb failure criteria. The model parameters were calibrated using results from the first field-scale test with a truck traveling at 48.3 km/hr (30 mph) impacting the LVAR system. The calibrated model was then used to simulate the second field-scale test, which involved a truck traveling at 80.5 km/hr (50 mph) impacting the same LVAR system without resetting the boulder or soil. The calibrated model was able to provide the global response of the system, including the time-history of the translational displacement and rotation of the boulder, and was in good agreement with field-scale test results. This suggests that the overall global response was dominated by the dynamic behavior of the truck and boulder system upon impact. Hence, a simple material model for soil and boulder is sufficient for simulating the tests conducted
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