3,403 research outputs found
Multi-strange baryon measurements at LHC energies, with the ALICE experiment
The status of the charged multi-strange baryon analysis (Xi-, anti-Xi+,
Omega-, anti-Omega+) at LHC energies is presented. This report is based on the
results obtained with ALICE (A Large Ion Collider Experiment), profiting from
the characteristic cascade-decay topology. A special attention is drawn to the
early pp data-taking period (2009-2010) and subsequently, on the uncorrected
pT-spectra extracted at mid-rapidity for centre of mass energies of 0.9 TeV and
7 TeV.Comment: 4 pages, 5 figures, Hot Quarks 2010 proceedings, La Londe Les Maures,
France, June 2010 (to be published in Journal of Physics: Conference Series
Experimental estimation of entanglement at the quantum limit
Entanglement is the central resource of quantum information processing and
the precise characterization of entangled states is a crucial issue for the
development of quantum technologies. This leads to the necessity of a precise,
experimental feasible measure of entanglement. Nevertheless, such measurements
are limited both from experimental uncertainties and intrinsic quantum bounds.
Here we present an experiment where the amount of entanglement of a family of
two-qubit mixed photon states is estimated with the ultimate precision allowed
by quantum mechanics.Comment: 4 pages, 3 figure
Discovery of a 500 pc shell in the nucleus of Centaurus A
Spitzer Space Telescope mid-infrared images of the radio galaxy Centaurus A
reveal a shell-like, bipolar, structure 500 pc to the north and south of the
nucleus. This shell is seen in 5.8, 8.0 and 24 micron broad-band images. Such a
remarkable shell has not been previously detected in a radio galaxy and is the
first extragalactic nuclear shell detected at mid-infrared wavelengths. We
estimate that the shell is a few million years old and has a mass of order
million solar masses. A conservative estimate for the mechanical energy in the
wind driven bubble is 10^53 erg. The shell could have created by a small few
thousand solar mass nuclear burst of star formation. Alternatively, the
bolometric luminosity of the active nucleus is sufficiently large that it could
power the shell. Constraints on the shell's velocity are lacking. However, if
the shell is moving at 1000 km/s then the required mechanical energy would be
100 times larger.Comment: submitted to ApJ Letter
Fluctuation and flow probes of early-time correlations in relativistic heavy ion collisions
Fluctuation and correlation observables are often measured using
multi-particle correlation methods and therefore mutually probe the origins of
genuine correlations present in multi-particle distribution functions. We
investigate the common influence of correlations arising from the spatially
inhomogeneous initial state on multiplicity and momentum fluctuations as well
as flow fluctuations. Although these observables reflect different aspects of
the initial state, taken together, they can constrain a correlation scale set
at the earliest moments of the collision. We calculate both the correlation
scale in an initial stage Glasma flux tube picture and the modification to
these correlations from later stage hydrodynamic flow and find quantitative
agreement with experimental measurements over a range of collision systems and
energies.Comment: Proceedings of the 28th Winter Workshop on Nuclear Dynamics, Dorado
del Mar, Puerto Rico, April 7-14, 201
Physical and physiologic determinants of rock climbing
Purpose:
Rock climbing performance relies on many characteristics. Here, we identified the physical and physiologic determinants of peak performance in rock climbing across the range from lower-grade to elite.
Methods:
44 male and 33 female climbers with onsight maximal climbing grades 5a-8a and 5a-7b+, respectively, were tested for physical, physiologic and psychologic characteristics (independent variables) that were correlated and modelled by multiple regression and principal component analysis to identify the determinants of rock climbing ability.
Results:
In males, 23 of 47 variables correlated with climbing ability (p<0.05, Pearson’s correlation coefficients 0.773-0.340), including shoulder endurance, hand and finger strength, shoulder power-endurance, hip flexibility, lower-arm grip strength, shoulder power, upper-arm strength, core-body endurance, upper-body aerobic endurance, hamstrings and lower-back flexibility, aerobic endurance, and open-hand finger strength. In females, 10 of 47 variables correlated with climbing ability (p<0.05, Pearson’s correlation coefficients 0.742-0.482): shoulder endurance and power, lower-arm grip strength, balance, aerobic endurance, and arm span. Principal component analysis and univariate multiple regression identified the main explanatory variables. In both sexes, shoulder power and endurance measured as maximum pull-ups, average arm crank power, and bent-arm hang, emerged as the main determinants (p<0.01; adjusted R2=0.77 in males and 0.62 in females). In males, finger pincer (p=0.07) and grip strength also had trends (p=0.09) toward significant effects. Finally, in test-of-principle training studies, we trained to increase main determinants 42-67%; this improved climbing ability 2-3 grades.
Conclusions:
Shoulder power and endurance majorly determines maximal climbing. Finger, hand and arm strength, core-body endurance, aerobic endurance, flexibility and balance are important secondary determinants
By the People: Hard Times, Hard Choices Michigan Residents Deliberate
Outlines the concept of deliberative polling and presents results from a face-to-face statewide deliberative poll on Michigan's economy and budget issues, including taxes, spending and benefits, the environment, and options for state assistance.For the first time, a scientific random sample of the people of Michigan gathered together to deliberate about the hard choices facing the state's economic future. Results of Michigan's first Deliberative Poll show what the people of the state would think if they could all become more informed and discuss the issues in depth. Highly representative in both attitudes and demographics, a sample of 314 participants deliberated for a long weekend in Lansing, with both small group discussions and questions answered by competing experts in plenary sessions. The resulting changes of opinion in the final survey offer some dramatic recommendations for both policymakers and the public
Formation time dependence of femtoscopic correlations in p+p collisions at =7 TeV
We investigate femtoscopic correlations using the UrQMD approach
combined with a correlation afterburner. The dependence of
correlations on the charged particle multiplicity and formation time in p+p
collisions at = 7 TeV is explored and compared to present ALICE
data. The data allows to constrain the formation time in the string
fragmentation to fm/c.Comment: 9 pages, 2 figure
Chandra Phase-Resolved X-ray Spectroscopy of the Crab Pulsar II
We present a new study of the X-ray spectral properties of the Crab Pulsar. The superb angular resolution of the Chandra X-ray Observatory enables distinguishing the pulsar from the surrounding nebulosity. Analysis of the spectrum as a function of pulse phase allows the least-biased measure of interstellar X-ray extinction due primarily to photoelectric absorption and secondarily to scattering by dust grains in the direction of the Crab Nebula. We modify previous findings that the line-of-sight to the Crab is under-abundant in oxygen and provide measurements with improved accuracy and less bias. Using the abundances and cross sections from Wilms, Allen & McCray (2000) we find [O/H] = (5.28+\-0.28) x 10(exp -4) (4.9 x 10(exp -4) is solar abundance). \rVe also measure for the first time the impact of scattering of flux out of the image by interstellar grains. \rYe find T(sub scat) = 0.147+/-0.043. Analysis of the spectrum as a function of pulse phase also measures the X-ray spectral index even at pulse minimum - albeit with increasing statistical uncertainty. The spectral variations are, by and large, consistent with a sinusoidal variation. The only significant variation from the sinusoid occurs over the same phase range as some rather abrupt behavior in the optical polarization magnitude and position angle. We compare these spectral variations to those observed in Gamma-rays and conclude that our measurements are both a challenge and a guide to future modeling and will thus eventually help us understand pair cascade processes in pulsar magnetospheres. The data were also used to set new. and less biased, upper limits to the surface temperature of the neutron star for different models of the neutron star atmosphere
Telemedicine follow up of Chronic Obstructive Pulmonary Disease Integrated into a Patient-centered Health Care Team Setting- Impacts on Patient Empowerment and Safety
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