1,101 research outputs found
The STACEE-32 Ground Based Gamma-ray Detector
We describe the design and performance of the Solar Tower Atmospheric
Cherenkov Effect Experiment detector in its initial configuration (STACEE-32).
STACEE is a new ground-based gamma ray detector using the atmospheric Cherenkov
technique. In STACEE, the heliostats of a solar energy research array are used
to collect and focus the Cherenkov photons produced in gamma-ray induced air
showers. The large Cherenkov photon collection area of STACEE results in a
gamma-ray energy threshold below that of previous detectors.Comment: 45 pages, 25 figures, Accepted for publication in Nuclear Instruments
and Methods
Adaptation of a Standard Extended-Release Naltrexone (XR-NTX) Protocol for Rural Re-Entering Offenders with OUD
BACKGROUND: Despite a growing body of empirical support for the effectiveness of extended-release naltrexone (XR-NTX) to reduce opioid relapse among people with opioid use disorder (OUD) transitioning from a correctional facility to the community, continuity of care following release remains challenging. This paper describes a research-based adaptation of a state\u27s standard of care XR-NTX protocol using the ADAPT-ITT framework for delivery in a non-traditional, non-treatment, community criminal justice setting (P&P office), as well as the expansion of services by a local Federally Qualified Health Center (FQHC) provider who would, for the first time, be going to the jail and P&P office to provide XR-NTX and related treatment.
METHOD: The present study focuses on the first seven phases (Assessment through Training) of the ADAPT-ITT framework in the adaptation of the Department of Corrections (DOC) protocol in preparation for a pilot trial for induction in a rural jail and during the transition to a rural community. Expert clinical review and focus groups with key stakeholders in criminal justice supervision and the local providers in the FQHC informed the needed adaptations to the existing XR-NTX protocol for initiation at the jail and ongoing administrations in the community.
RESULTS: Findings from stakeholder focus groups, study team review, topical expert review, and a theater test suggested that there were critical adaptations needed in both content and context at the patient and clinic level.
CONCLUSION: Health and justice officials should consider the need to tailor and adapt evidence-based approaches for real-world locations that high-risk, justice-involved individuals visit in order to reduce barriers and increase access to critically needed treatment for OUD
Two-stage multilevel latent class analysis with covariates in the presence of direct effects
Multivariate analysis of psychological dat
The ATLAS3D project - XXV: Two-dimensional kinematic analysis of simulated galaxies and the cosmological origin of fast and slow rotators
We present a detailed two-dimensional stellar dynamical analysis of as ample of 44 cosmological hydrodynamical simulations of individual central galaxies with stellar masses of 2 x 1010Msun ∼≤ Mstar ∼≤ 6x 1011Msun. Kinematic maps of the stellar line-of-sight velocity, velocity dispersion, and higher-order Gauss-Hermite moments h3 and h4 are constructed for each central galaxy and for the most massive satellites. The amount of rotation is quantified using the λR-parameter. The velocity, velocity dispersion, h3, and h4 fields of the simulated galaxies show a diversity similar to observed kinematic maps of early-type galaxies in the ATLAS3D survey. This includes fast (regular), slow, and misaligned rotation, hot spheroids with embedded cold disk components as well as galaxies with counter-rotating cores or central depressions in the velocity dispersion. We link the present-day kinematic properties to the individual cosmological formation histories of the galaxies. In general, major galaxy mergers have a significant influence on the rotation properties resulting in both a spin-down as well as a spin-up of the merger remnant. Lower mass galaxies with significant in-situ formation of stars, or with additional gas-rich major mergers - resulting in a spin-up - in their formation history, form elongated fast rotators with a clear anti-correlation of h3 and v/σ. An additional formation path for fast rotators includes gas-poor major mergers leading to a spin-up of the remnants. This formation path does not result in anti-correlated h3 and v/σ. The galaxies most consistent with the rare class of non-rotating round early-type galaxies grow by gas-poor minor mergers alone. In general, more massive galaxies have less in-situ star formation since z ∼ 2, rotate slower and have older stellar populations. (shortened)PostprintPeer reviewe
Ultra deep sub-kpc view of nearby massive compact galaxies
Using Gemini North telescope ultra deep and high resolution (sub-kpc) K-band
adaptive optics imaging of a sample of 4 nearby (z~0.15) massive
(~10^{11}M_sun) compact (R<1.5 kpc) galaxies, we have explored the structural
properties of these rare objects with an unprecedented detail. Our surface
brightness profiles expand over 12 magnitudes in range allowing us to explore
the presence of any faint extended envelope on these objects down to stellar
mass densities ~10^{6} M_sun/kpc^{2} at radial distances of ~15 kpc. We find no
evidence for any extended faint tail altering the compactness of these
galaxies. Our objects are elongated, resembling visually S0 galaxies, and have
a central stellar mass density well above the stellar mass densities of objects
with similar stellar mass but normal size in the present universe. If these
massive compact objects will eventually transform into normal size galaxies,
the processes driving this size growth will have to migrate around
2-3x10^{10}M_sun stellar mass from their inner (R<1.7 kpc) region towards their
outskirts. Nearby massive compact galaxies share with high-z compact massive
galaxies not only their stellar mass, size and velocity dispersion but also the
shape of their profiles and the mean age of their stellar populations. This
makes these singular galaxies unique laboratories to explore the early stages
of the formation of massive galaxies.Comment: Accepted for publication in ApJ Letter. Version revised to match the
accepted versio
Recommended from our members
Initial Development of a Continuous Emission Monitor for Dioxins
Under contract DE-AC26-98FT-40370, SRI International has completed the third phase of a planned three-phase effort to develop a laboratory prototype continuous emission monitor (CEM) for dioxins and furans generated during the incineration of waste materials at DOE remediation sites. The project was initiated on July 29, 1998 with the technical effort completed in October 2001. During this research effort, SRI has made numerous improvements in our jet-REMPI instrument. These improvements have involved characterization and optimization of the molecular cooling in the gas jet, implementation of a custom-fabricated, four pulsed valve assembly, new data acquisition and display software, and preliminary development of a wavelength and mass calibration approach. We have also measured the REMPI excitation spectra of numerous organic compounds that are likely to be present in the exhaust stream of a waste incinerator. These spectra must be well characterized in the laboratory to understand any potential interferences that might arise when monitoring for dioxin and furan congeners. Our results to date continue to validate the original concept of using jet-REMPI as the detection method in a dioxin CEM. Using only commercial components with minor modifications, we have already demonstrated a detection sensitivity in the low ppt range with sufficient chemical specificity to separately detect two closely related congeners of dichlorodibenzodioxin present in a mixture. To demonstrate the utility of this methodology outside of the controlled conditions of the laboratory, we performed a series of pseudo-field experiments at the US Environmental Protection Agency's National Risk Management Research Laboratory, Research Triangle Park, NC. The instrument used for those studies was built by SRI under contract with US EPA, and was an exact duplicate of the SRI system. This duplication allowed the experiments to be conducted without transporting the SRI system to the EPA site. Using the jet-REMPI system in conjunction with a combustion flow reactor, the joint SRI-EPA team discovered several new, and unexpected, chemical species in the exhaust stream of a pure methane flame. Based on our work in this project, we have developed a number of concepts for instrumental improvements that will substantially increase our sensitivity while maintaining the exceptional selectivity required of a dioxin CEM. In addition, we have developed several system configurations with varying degrees of functionality that can be further developed and deployed for process monitoring, surrogate measurements, and potentially, as a dioxin control CEM. Due to the extremely demanding regulatory compliance monitoring requirements involving both congener specificity and sub-part-per-trillion sensitivity with near real-time speed, we believe it is not as yet possible to specify a system configuration for a true dioxin compliance monitor. While a true TEQ compliance monitor is not yet possible using the jet-REMPI approach, the technique may prove useful as a surrogate, or indicator monitor. This application would involve continuous measurement of surrogate compounds, such as lowly chlorinated dioxins and furans, whose concentrations have been previously correlated with the TEQ. Such an instrument would not require the extreme sensitivity of a compliance monitor although the high degree of chemical selectivity would remain important
Mrk 421, Mrk 501, and 1ES 1426+428 at 100 GeV with the CELESTE Cherenkov Telescope
We have measured the gamma-ray fluxes of the blazars Mrk 421 and Mrk 501 in
the energy range between 50 and 350 GeV (1.2 to 8.3 x 10^25 Hz). The detector,
called CELESTE, used first 40, then 53 heliostats of the former solar facility
"Themis" in the French Pyrenees to collect Cherenkov light generated in
atmospheric particle cascades. The signal from Mrk 421 is often strong. We
compare its flux with previously published multi-wavelength studies and infer
that we are straddling the high energy peak of the spectral energy
distribution. The signal from Mrk 501 in 2000 was weak (3.4 sigma). We obtain
an upper limit on the flux from 1ES 1426+428 of less than half that of the Crab
flux near 100 GeV. The data analysis and understanding of systematic biases
have improved compared to previous work, increasing the detector's sensitivity.Comment: 15 pages, 14 figures, accepted to A&A (July 2006) August 19 --
corrected error in author lis
Increasing Employee Awareness of the Signs and Symptoms of Heart Attack and the Need to Use 911 in a State Health Department
INTRODUCTION: Early recognition of the signs and symptoms of a heart attack can lead to reduced morbidity and mortality. METHODS: A workplace intervention was conducted among 523 Montana state health department employees in 2003 to increase awareness of the signs and symptoms of heart attack and the need to use 911. All employees received an Act in Time to Heart Attack Signs brochure and wallet card with their paychecks. Act in Time posters were placed in key workplace areas. A weekly e-mail message, including a contest entry opportunity addressing the signs and symptoms of heart attack, was sent to all employees. Baseline and follow-up telephone surveys were conducted to evaluate intervention effectiveness. RESULTS: Awareness of heart attack signs and symptoms and the need to call 911 increased significantly among employees from baseline to follow-up: pain or discomfort in the jaw, neck, or back (awareness increased from 69% to 91%); feeling weak, light-headed, or faint (awareness increased from 79% to 89%); call 911 if someone is having a heart attack or stroke (awareness increased from 84% to 90%). Awareness of chest pain, pain or discomfort in the arms or shoulders, and shortness of breath were more than 90% at baseline and did not increase significantly at follow-up. At baseline, 69% of respondents correctly reported five or more of the signs and symptoms of heart attack; 89% reported correctly at follow-up. CONCLUSION: This low-cost workplace intervention increased awareness of the signs and symptoms of heart attack and the need to call 911
Very high energy observations of the BL Lac objects 3C 66A and OJ 287
Using the Solar Tower Atmospheric Cherenkov Effect Experiment (STACEE), we
have observed the BL Lac objects 3C 66A and OJ 287. These are members of the
class of low-frequency-peaked BL Lac objects (LBLs) and are two of the three
LBLs predicted by Costamante and Ghisellini to be potential sources of very
high energy (>100 GeV) gamma-ray emission. The third candidate, BL Lacertae,
has recently been detected by the MAGIC collaboration. Our observations have
not produced detections; we calculate a 99% CL upper limit of flux from 3C 66A
of 0.15 Crab flux units and from OJ 287 our limit is 0.52 Crab. These limits
assume a Crab-like energy spectrum with an effective energy threshold of 185
GeV.Comment: 24 pages, 15 figures, Accepted for publication in Astroparticle
Physic
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