337 research outputs found
The Central Laser Facility at the Pierre Auger Observatory
The Central Laser Facility is located near the middle of the Pierre Auger
Observatory in Argentina. It features a UV laser and optics that direct a beam
of calibrated pulsed light into the sky. Light scattered from this beam
produces tracks in the Auger optical detectors which normally record nitrogen
fluorescence tracks from cosmic ray air showers. The Central Laser Facility
provides a "test beam" to investigate properties of the atmosphere and the
fluorescence detectors. The laser can send light via optical fiber
simultaneously to the nearest surface detector tank for hybrid timing analyses.
We describe the facility and show some examples of its many uses.Comment: 4 pages, 5 figures, submitted to 29th ICRC Pune Indi
Spatial Processes Decouple Management from Objectives in a Heterogeneous Landscape: Predator Control as a Case Study
Predator control is often implemented with the intent of disrupting top‐down regulation in sensitive prey populations. However, ambiguity surrounding the efficacy of predator management, as well as the strength of top‐down effects of predators in general, is often exacerbated by the spatially implicit analytical approaches used in assessing data with explicit spatial structure. Here, we highlight the importance of considering spatial context in the case of a predator control study in south‐central Utah. We assessed the spatial match between aerial removal risk in coyotes (Canis latrans) and mule deer (Odocoileus hemionus) resource selection during parturition using a spatially explicit, multi‐level Bayesian model. With our model, we were able to evaluate spatial congruence between management action (i.e., coyote removal) and objective (i.e., parturient deer site selection) at two distinct scales: the level of the management unit and the individual coyote removal. In the case of the former, our results indicated substantial spatial heterogeneity in expected congruence between removal risk and parturient deer site selection across large areas, and is a reflection of logistical constraints acting on the management strategy and differences in space use between the two species. At the level of the individual removal, we demonstrated that the potential management benefits of a removed coyote were highly variable across all individuals removed and in many cases, spatially distinct from parturient deer resource selection. Our methods and results provide a means of evaluating where we might anticipate an impact of predator control, while emphasizing the need to weight individual removals based on spatial proximity to management objectives in any assessment of large‐scale predator control. Although we highlight the importance of spatial context in assessments of predator control strategy, we believe our methods are readily generalizable in any management or large‐scale experimental framework where spatial context is likely an important driver of outcomes
Charmed meson decay constants in three-flavor lattice QCD
We present the first lattice QCD calculation with realistic sea quark content
of the D^+ meson decay constant f_{D^+}. We use the MILC Collaboration's
publicly available ensembles of lattice gauge fields, which have a quark sea
with two flavors (up and down) much lighter than a third (strange). We obtain
f_{D^+} = 201 +/- 3 +/- 17 MeV, where the errors are statistical and a
combination of systematic errors. We also obtain f_{D_s} = 249 +/- 3 +/- 16 MeV
for the D_s meson.Comment: note added on recent CLEO measurement; PRL versio
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Techniques of the FLASH Thin Target Experiment
The fluorescence yield in air is reported for wavelength and pressure ranges of interest to ultra-high energy cosmic ray detectors. A 28.5 GeV electron beam was used to excite the fluorescence. Central to the approach was the system calibration, using Rayleigh scattering of a nitrogen laser beam. In atmospheric pressure dry air, at 304 K the yield is 20.8 {+-} 1.6 photons per MeV
Deep Underground Science and Engineering Lab: S1 Dark Matter Working Group
A study of the current status of WIMP dark matter searches has been made in
the context of scientific and technical planning for a Deep Underground Science
and Engineering Laboratory (DUSEL) in the U.S. The table of contents follows:
1. Overview
2. WIMP Dark Matter: Cosmology, Astrophysics, and Particle Physics
3. Direct Detection of WIMPs
4. Indirect Detection of WIMPs
5. Dark Matter Candidates and New Physics in the Laboratory
6. Synergies with Other Sub-Fields
7. Direct Detection Experiments: Status and Future Prospects
8. Infrastructure
9. International Context
10. Summary and Outlook
11. AcknowledgmentsComment: Final working group report of 17 Feb 2007 updated to address reviewer
comments (Latex, 32 pages
STRP Screening Sets for the human genome at 5 cM density
BACKGROUND: Short tandem repeat polymorphisms (STRPs) are powerful tools for gene mapping and other applications. A STRP genome scan of 10 cM is usually adequate for mapping single gene disorders. However mapping studies involving genetically complex disorders and especially association (linkage disequilibrium) often require higher STRP density. RESULTS: We report the development of two separate 10 cM human STRP Screening Sets (Sets 12 and 52) which span all chromosomes. When combined, the two Sets contain a total of 782 STRPs, with average STRP spacing of 4.8 cM, average heterozygosity of 0.72, and total sex-average coverage of 3535 cM. The current Sets are comprised almost entirely of STRPs based on tri- and tetranucleotide repeats. We also report correction of primer sequences for many STRPs used in previous Screening Sets. Detailed information for the new Screening Sets is available from our web site: . CONCLUSION: Our new human STRP Screening Sets will improve the quality and cost effectiveness of genotyping for gene mapping and other applications
Evaluation of Secondary Consolidation Settlement Associated With Embankment Construction for Fast-Paced Transportation Projects in Utah
12-9310This report discusses the design and implementation of surcharging technology in terms of the required laboratory, field and engineering evaluations. It is hoped that such information will provide a more consistent and technically defensible rationale for deploying this technology on highway projects constructed atop soft soils. Surcharging or preloading of the earthen embankments and underlying compressible soils is the most commonly deployed strategy to reduce the magnitude of secondary compression. Surcharging or overconsolidating of the foundation soils can be used to reduce the post-construction secondary settlement. In the course of this research, twenty-two consolidation tests and eighty-eight time rate tests were performed on Pleistocene and recent fine-grained, cohesive, lacustrine deposits comprised of Lake Bonneville and more recent clays, most likely of Utah Lake origin located along the Wasatch Front in Utah. Prior to analyzing the data, the test results were screened using the sample quality designation (SQD). Plots of the adjusted amount of surcharge (AAOS) were plotted versus the normalized rate of secondary settlement (C\u3b1\u2019/C\u3b1) and compared with the research performed by Ng (1998). The data from this thesis plots higher than that reported by Ng (1998). This higher trend agrees better with the long-term settlement performance monitoring data obtained from the I-15 Reconstruction Project in Salt Lake County, Utah. Data from the time rate tests were used to determine the C\u3b1/CR ratio, giving a mean value of C\u3b1/CR = 0.0442. This value compared favorably with the research performed by Ng (1998), which had a value of C\u3b1/CR = 0.0433. Also provided with this report is a recommended method for designing surcharge fills considering post-construction (i.e., secondary compression) settlement
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