5,216 research outputs found
Photon + Jet production at sqrt{s}=1.96 TeV
Prompt photon production results by the CDF and D\OCollaborations in the
Tevatron Run II at a center of mass energy of =1.96 TeV are
presented. Cross sections for central isolated photons, photon+jet production
and photons produced in association with a heavy flavor quark are reported. The
measurements are compared to Next-to-Leading order perturbative QCD
predictions.Comment: 4 pages, 6 figures, Proceedings for the QCD Session at Moriond 200
Management of Elbow Dislocations in the National Football League.
Background: Although much literature exists regarding the treatment and management of elbow dislocations in the general population, little information is available regarding management in the athletic population. Furthermore, no literature is available regarding the postinjury treatment and timing of return to play in the contact or professional athlete.
Purpose: To review the clinical course of elbow dislocations in professional football players and determine the timing of return to full participation.
Study Design: Case series; Level of evidence, 4.
Methods: All National Football League (NFL) athletes with elbow dislocations from 2000 through 2011 who returned to play during the season were identified from the NFL Injury Surveillance System (NFL ISS). Roster position, player activity, use of external bracing, and clinical course were reviewed. Mean number of days lost until full return to play was determined for players with elbow dislocations who returned in the same season.
Results: From 2000 to 2011, a total of 62 elbow dislocations out of 35,324 injuries were recorded (0.17%); 40 (64.5%) dislocations occurred in defensive players, 12 (19.4%) were in offensive players; and 10 (16.1%) were during special teams play. Over half of the injuries (33/62, 53.2%) were sustained while tackling, and 4 (6.5%) patients required surgery. A total of 47 (75.8%) players who sustained this injury were able to return in the same season. For this group, the mean number of days lost in players treated conservatively (45/47) was 25.1 days (median, 23.0 days; range, 0.0-118 days), while that for players treated operatively (2/47) was 46.5 days (median, 46.5 days; range, 29-64 days). Mean return to play based on player position was 25.8 days for defensive players (n = 28; median, 21.5 days; range, 3.0-118 days), 24.1 days for offensive players (n = 11; median, 19 days; range, 2.0-59 days), and 25.6 days for special teams players (n = 8; median, 25.5 days; range, 0-44 days).
Conclusion: Elbow dislocations comprise less than a half of a percent of all injuries sustained in the NFL. Most injuries occur during the act of tackling, with the majority of injured athletes playing a defensive position. Players treated nonoperatively missed a mean of 25.1 days, whereas those managed operatively missed a mean of 46.5 days
Temperature and Emission-Measure Profiles Along Long-Lived Solar Coronal Loops Observed with TRACE
We report an initial study of temperature and emission measure distributions
along four steady loops observed with the Transition Region and Coronal
Explorer (TRACE) at the limb of the Sun. The temperature diagnostic is the
filter ratio of the extreme-ultraviolet 171-angstrom and 195-angstrom
passbands. The emission measure diagnostic is the count rate in the
171-angstrom passband. We find essentially no temperature variation along the
loops. We compare the observed loop structure with theoretical isothermal and
nonisothermal static loop structure.Comment: 10 pages, 3 postscript figures (LaTeX, uses aaspp4.sty). Accepted by
ApJ Letter
Effect of Concave Wall Geometry on Heat Transfer in Hypersonic Boundary Layers
Heat transfer measurements are made to investigate the effects of concave surface curvature on a high-stagnation enthalpy boundary layer in a Mach 5.1 flow. Experiments are
carried out using two curved models with 16 and 25 degree turning angles, and baseline
planar models (at plate and linear ramp) for comparative study. Streamwise and spanwise
cross-sections are obtained. Significant destabilization of the boundary layer is observed
over the adverse pressure gradient geometries. For the curved surfaces, the heat flux distribution appears to exhibit a quadratic dependence with streamwise distance, in contrast
with the linear dependence observed on the linear ramp
The Minimum of Solar Cycle 23: As Deep as It Could Be?
In this work we introduce a new way of binning sunspot group data with the
purpose of better understanding the impact of the solar cycle on sunspot
properties and how this defined the characteristics of the extended minimum of
cycle 23. Our approach assumes that the statistical properties of sunspots are
completely determined by the strength of the underlying large-scale field and
have no additional time dependencies. We use the amplitude of the cycle at any
given moment (something we refer to as activity level) as a proxy for the
strength of this deep-seated magnetic field.
We find that the sunspot size distribution is composed of two populations:
one population of groups and active regions and a second population of pores
and ephemeral regions. When fits are performed at periods of different activity
level, only the statistical properties of the former population, the active
regions, is found to vary.
Finally, we study the relative contribution of each component (small-scale
versus large-scale) to solar magnetism. We find that when hemispheres are
treated separately, almost every one of the past 12 solar minima reaches a
point where the main contribution to magnetism comes from the small-scale
component. However, due to asymmetries in cycle phase, this state is very
rarely reached by both hemispheres at the same time. From this we infer that
even though each hemisphere did reach the magnetic baseline, from a
heliospheric point of view the minimum of cycle 23 was not as deep as it could
have been
Distribuzione spaziale dei popolamenti a <i>Lithophyllum byssoides</i>, a <i>Patella ferruginea</i> e della frangia a <i>Cystoseira</i> sp. nell'Arcipelago di La Maddalena (Sardegna-Italia) = Spatial distribution of <i>Lithophyllum byssoides</i>, <i>Patella ferruginea</i> assemblage and <i>Cystoseira</i> sp. fringe in The Maddalena Archipelago (Sardinia-Italy)
A study on the distribution of Lithophyllum byssoides, Patella ferruginea and Cystoseira sp. fringe populations, has been carried out in the national Park of the La Maddalena archipelago. Those species has been protected from international conventions as rare species in danger of extinction. The results of the study shows a good conservation state of the examined islands
Kinetic pinning and biological antifreezes
Biological antifreezes protect cold-water organisms from freezing. An example
are the antifreeze proteins (AFPs) that attach to the surface of ice crystals
and arrest growth. The mechanism for growth arrest has not been heretofore
understood in a quantitative way. We present a complete theory based on a
kinetic model. We use the `stones on a pillow' picture. Our theory of the
suppression of the freezing point as a function of the concentration of the AFP
is quantitatively accurate. It gives a correct description of the dependence of
the freezing point suppression on the geometry of the protein, and might lead
to advances in design of synthetic AFPs.Comment: 4 pages, 4 figure
The approach to thermalization in the classical phi^4 theory in 1+1 dimensions: energy cascades and universal scaling
We study the dynamics of thermalization and the approach to equilibrium in
the classical phi^4 theory in 1+1 spacetime dimensions. At thermal equilibrium
we exploit the equivalence between the classical canonical averages and
transfer matrix quantum traces of the anharmonic oscillator to obtain exact
results for the temperature dependence of several observables, which provide a
set of criteria for thermalization. We find that the Hartree approximation is
remarkably accurate in equilibrium. The non-equilibrium dynamics is studied by
numerically solving the equations of motion in light-cone coordinates for a
broad range of initial conditions and energy densities.The time evolution is
described by several stages with a cascade of energy towards the ultraviolet.
After a transient stage, the spatio-temporal gradient terms become larger than
the nonlinear term and a stage of universal cascade emerges.This cascade starts
at a time scale t_0 independent of the initial conditions (except for very low
energy density). Here the power spectra feature universal scaling behavior and
the front of the cascade k(t) grows as a power law k(t) sim t^alpha with alpha
lesssim 0.25. The wake behind the cascade is described as a state of Local
Thermodynamic Equilibrium (LTE) with all correlations being determined by the
equilibrium functional form with an effective time dependent temperatureTeff(t)
which slowly decreases as sim t^{-alpha}.Two well separated time scales emerge
while Teff(t) varies slowly, the wavectors in the wake with k < k(t) attain LTE
on much shorter time scales.This universal scaling stage ends when the front of
the cascade reaches the cutoff at a time t_1 sim a^{-1/alpha}. Virialization
starts to set much earlier than LTE. We find that strict thermalization is
achieved only for an infinite time scale.Comment: relevance for quantum field theory discussed providing validity
criteria. To appear in Phys. Rev.
Contemplative Science: An Insider's Prospectus
This chapter describes the potential far‐reaching consequences of contemplative higher education for the fields of science and medicine
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