2,142 research outputs found
The ATLAS liquid argon hadronic end-cap calorimeter: construction and selected beam test results
ATLAS has chosen for its Hadronic End-Cap Calorimeter (HEC) the copper-liquid
argon sampling technique with flat plate geometry and GaAs pre-amplifiers in
the argon. The contruction of the calorimeter is now approaching completion.
Results of production quality checks are reported and their anticipated impact
on calorimeter performance discussed. Selected results, such as linearity,
electron and pion energy resolution, uniformity of energy response, obtained in
beam tests both of the Hadronic End-Cap Calorimeter by itself, and in the ATLAS
configuration where the HEC is in combination with the Electromagnetic End-Cap
Calorimeter (EMEC) are described.Comment: 4 pages, 2 figures,IPRD04 conferenc
The MAJORANA 76Ge neutrino less double-beta decay project: A brief update
At present, MAJORANA is a research and development (R&D) project to
investigate the feasibility and cost of constructing and operating a one ton
decay experiment with ~1000 kg of Ge detectors fabricated from germanium
enriched to 86% in . The study will include three separate cryostats with
various types of detectors: un-segmented, un-segmented point-contact, minimally
segmented, and highly segmented. One cryostat will contain at least 30 kg of
enriched (preferably point-contact) detectors. The performance of the cryostats
and detectors as well as background levels will be investigated. The goal of
the demonstrator project is to reach a discovery sensitivity of ~ 1026 y.Comment: 3 pages, no figure
HUNK Phosphorylates Rubicon to Support Autophagy
Background: Autophagy is a catabolic cellular recycling pathway that is essential for maintaining intracellular homeostasis. Autophagosome formation is achieved via the coordination of the Beclin-1 protein complex. Rubicon is a Beclin-1 associated protein that suppresses autophagy by impairing the activity of the class III PI3K, Vps34. However, very little is known about the molecular mechanisms that regulate Rubicon function. Methods: In this study, co-immunoprecipitation and kinase assays were used to investigate the ability of Hormonally Upregulated Neu-associated Kinase (HUNK) to bind to and phosphorylate Rubicon. LC3B was monitored by immunofluorescence and immunoblotting to determine whether phosphorylation of Rubicon by HUNK controls the autophagy suppressive function of Rubicon. Results: Findings from this study identify Rubicon as a novel substrate of HUNK and show that phosphorylation of Rubicon inhibits its function, promoting autophagy
THE RELATIONSHIP BETWEEN MUSCULOSKELETAL STRENGTH, PHYSIOLOGICAL CHARACTERISTICS, AND KNEE KINESTHESIA FOLLOWING FATIGUING EXERCISE
Fatiguing exercise may result in impaired functional joint stability and increased risk of unintentional injury. While there are several musculoskeletal and physiological characteristics related to fatigue onset, their relationship with proprioceptive changes following fatigue has not been examined. The purpose of this study was to establish the relationship between musculoskeletal and physiological characteristics and changes in proprioception, measured by threshold to detect passive motion (TTDPM), following fatiguing exercise. Twenty, physically active females participated (age: 28.65 ± 5.6 years, height: 165.6 ± 4.3 cm, weight: 61.8 ± 8.0 kg, BMI: 22.5± 2.3 kg/m2, BF: 23.3 ± 5.4%). During Visit 1, subjects completed an exercise history and 24-hour dietary questionnaire, and body composition, TTDPM familiarization, isokinetic knee strength, and maximal oxygen uptake/lactate threshold assessments. During Visit 2, subjects completed TTDPM and isometric knee strength testing prior to and following a fatiguing exercise protocol. Wilcoxon signed rank tests determined TTDPM and isometric knee strength changes from pre- to post- fatigue. Spearman’s rho correlation coefficients determined the relationship between strength and physiological variables with pre- to post-fatigue changes in TTDPM and with pre-fatigue and post-fatigue TTDPM in extension and flexion (α=0.05). No significant differences were demonstrated from pre-fatigue to post-fatigue TTDPM despite a significant decrease in isometric knee flexion strength (P<0.01) and flexion/extension ratio (P<0.05) following fatigue. No significant correlations were observed between strength or physiological variables and changes in TTDPM from pre- to post-fatigue in extension or flexion. Flexion/extension ratio was significantly correlated with pre-fatigue TTDPM in extension (r=-0.231, P<0.05). Peak oxygen uptake was significantly correlated with pre-fatigue (r=-0.500, P<0.01) and post-fatigue (r=-0.520, P<0.05) TTDPM in extension. No significant relationships were demonstrated between musculoskeletal and physiological characteristics and changes in TTDPM following fatigue. The results suggest that highly trained individuals may have better proprioception, and that the high fitness level of subjects in this investigation may have contributed to absence of TTDPM deficits following fatigue despite reaching a high level of perceptual and physiological fatigue. Future studies should consider various subject populations, other musculoskeletal strength characteristics, and different modalities of proprioception to determine the most important contributions to proprioceptive changes following fatigue
ECONOMICALLY OPTIMAL WILDFIRE INTERVENTION REGIMES
Wildfires in the United States result in total damages and costs that are likely to exceed billions of dollars annually. Land managers and policy makers propose higher rates of prescribed burning and other kinds of vegetation management to reduce amounts of wildfire and the risks of catastrophic losses. A wildfire public welfare maximization function, using a wildfire production function estimated using a time series model of a panel of Florida counties, is employed to simulate the publicly optimal level of prescribed burning in an example county in Florida (Volusia). Evaluation of the production function reveals that prescribed fire is not associated with reduced catastrophic wildfire risks in Volusia County Florida, indicating a short-run elasticity of -0.16 and a long-run elasticity of wildfire with respect to prescribed fire of -0.07. Stochastic dominance is used to evaluate the optimal amount of prescribed fire most likely to maximize a measure of public welfare. Results of that analysis reveal that the optimal amount of annual prescribed fire is about 3 percent (9,000 acres/year) of the total forest area, which is very close to the actual average amount of prescribed burning (12,700 acres/year) between 1994-99.Resource /Energy Economics and Policy,
Abundance analysis of prime B-type targets for asteroseismology II. B6--B9.5 stars in the field of view of the CoRoT
The CoRoT satellite is collecting precise time-resolved photometry for tens
of asteroseismology targets. To ensure a correct interpretation of the CoRoT
data, the atmospheric parameters, chemical compositions, and rotational
velocities of the stars must be determined. The main goal of the ground-based
seismology support program for the CoRoT mission was to obtain photometric and
spectroscopic data for stars in the fields monitored by the satellite. These
ground-based observations were collected in the GAUDI archive. High-resolution
spectra of more than 200 B-type stars are available in this database, and about
45% of them is analysed here. To derive the effective temperature of the stars,
we used photometric indices. Surface gravities were obtained by comparing
observed and theoretical Balmer line profiles. To determine the chemical
abundances and rotational velocities, we used a spectrum synthesis method,
which consisted of comparing the observed spectrum with theoretical ones based
on the assumption of LTE. Atmospheric parameters, chemical abundances, and
rotational velocities were determined for 89 late-B stars. The dominant species
in their spectra are iron-peak elements. The average Fe abundance is
7.24+/-0.45 dex. The average rotational velocity is 126 km/sec, but there are
13 and 20 stars with low and moderate Vsin i values, respectively. The analysis
of this sample of 89 late B-type stars reveals many chemically peculiar (CP)
stars. Some of them were previously known, but at least 9 new CP candidates,
among which at least two HgMn stars, are identified in our study. These CP
stars as a group exhibit Vsin i values lower than the stars with normal surface
chemical composition.Comment: 21 pages, 13 figures, accepted to Astronomy and Astrophysic
Diffractive Meson Production and the Quark-Pomeron Coupling
Diffractive meson production at HERA offers interesting possibilities to
investigate diffractive processes and thus to learn something about the
properties of the pomeron. The most succesful phenomenological description of
the pomeron so far assumes it to couple like a isoscalar photon to
single quarks. This coupling leads, however, to problems for exclusive
diffractive reactions. We propose a new phenomenological pomeron vertex, which
leads to very good fits to the known data, but avoids the problems of the old
vertex.Comment: 20 pages, latex with uuencoded postscript, revised versio
Physical Performance Differences in Sea, Air and Land (SEAL) Operator Cohorts Separated by Demographics
Please refer to the pdf version of the abstract located adjacent to the title
Atmospheric velocity fields in tepid main sequence stars
The line profiles of the stars with v sin i below a few km/s can reveal
direct signatures of local velocity fields (e.g. convection) in stellar
atmospheres. This effect is well established in cool main sequence stars, and
has been detected and studied in three A stars. This paper reports observations
of main sequence B, A and F stars with two goals: (1) to identify additional
stars having sufficiently low values of v sin i to search for spectral line
profile signatures of local velocity fields, and (2) to explore how the
signatures of the local velocity fields in the atmosphere depend on stellar
parameters such as effective temperature T_eff and peculiarity type.
For stars having T_eff below about 10000 K, we always detect local
atmospheric velocity fields indirectly through a non-zero microturbulence
parameter, but not for hotter stars. Among the A and F stars in our sample
having the sharpest lines, direct tracers of atmospheric velocity fields are
found in six new stars. The velocity field signatures identified include
asymmetric excess line wing absorption, deeper in the blue line wing than in
the red; line profiles of strong lines that are poorly fit by computed
profiles; and strong lines that are broader than they should be for the v sin i
values deduced from weak lines. These effects are found in both normal and Am
stars, but seem stronger in Am stars.
These data still have not been satisfactorily explained by models of
atmospheric convection, including numerical simulations.Comment: Acepted for publication by Astronomy and Astrophysic
The Gamification of Augmented Reality Art
Augmented Reality (AR) and its applications are being used in many applications, including gaming, education, industry, research, and art. Gamification refers to the merging of games with interactive media (video games, Virtual and Augmented Realities, for example) to allow for the completion of difficult digital labour of research in a more fun, intuitive fashion. In this chapter, the merging of gamification and Augmented Reality-based art is discussed, its impact in terms of digital labour as well as examples of Augmented Reality that exhibit gamification or elements of it. Speculative design fictions of gamified Augmented Reality are examined to determine possible future outcomes of this genre. Lastly historical experiments in user interface design are mentioned to propose future solutions for Augmented Reality applications, artistic installations and gamification scenarios
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