138 research outputs found
Noncomminuted lateral end clavicle fractures associated with coracoclavicular ligament disruption: technical considerations for optimal anatomic fixation and stability
Distal clavicle fractures associated with coracoclavicular ligament disruption are potentially unstable and necessitate surgical treatment. Current fixation techniques are nonanatomic and do not address relevant aspects of the pathoanatomy. We have developed a technique that uses a unique combination of implants; this permits minimally invasive fixation and stable reduction with a lateral fragment size as small as 5 mm. The surgical technique consists of (1) neutralization of muscular forces on the proximal fragment using a minimally invasive ligament repair device (TightRope™, Arthrex, FL, USA) and (2) internal fixation using a contour-matched locking plate (2.4 mm LCP(®) Distal radius plates, Synthes, USA). Technical tips to optimize this new procedure are discussed. The technique can be extended to an “arthroscopic-assisted” method involving arthroscopic coracoclavicular fixation followed by a mini-open plate fixation of the clavicular fragments
Performance investigation of an innovative H-bridge derived multilevel inverter topology for marine applications
441-449An innovative single-phase and three-phase H-bridge derived multilevel inverter topology is being proposed in this manuscript. The proposed topology makes use of relatively fewer switching devices compared to conventional Cascaded H-Bridge (CHB) multilevel inverter. In other words, the proposed inverter topology is capable of producing more number of levels in the voltage waveform with same number of switching devices. It is also established in this paper, that this proposed topology is superior in terms of requirement of lesser number of gate driving circuits and reduction in the harmonic content in the output voltage waveform. The proposed inverter topologies are driven by SPWM modulation technique. These converter topologies are not only beneficial for the power conditioning systems in the power system network but also for the other novel applications like in marine ships. In this manuscript, the performance comparisons of the proposed inverter topologies with that of conventional topology based on simulation results with MATLAB/SIMULINK have been presented
An entropic uncertainty principle for positive operator valued measures
Extending a recent result by Frank and Lieb, we show an entropic uncertainty
principle for mixed states in a Hilbert space relatively to pairs of positive
operator valued measures that are independent in some sense. This yields
spatial-spectral uncertainty principles and log-Sobolev inequalities for
invariant operators on homogeneous spaces, which are sharp in the compact case.Comment: 14 pages. v2: a technical assumption removed in main resul
Pion interferometry in Au+Au collisions at sqrt[sNN]=200GeV
We present a systematic analysis of two-pion interferometry in Au+Au collisions at sqrt[sNN]=200GeV using the STAR detector at Relativistic Heavy Ion Collider. We extract the Hanbury-Brown and Twiss radii and study their multiplicity, transverse momentum, and azimuthal angle dependence. The Gaussianness of the correlation function is studied. Estimates of the geometrical and dynamical structure of the freeze-out source are extracted by fits with blast-wave parametrizations. The expansion of the source and its relation with the initial energy density distribution is studied
Pion, kaon, proton and anti-proton transverse momentum distributions from p+p and d+Au collisions at GeV
Identified mid-rapidity particle spectra of , , and
from 200 GeV p+p and d+Au collisions are reported. A
time-of-flight detector based on multi-gap resistive plate chamber technology
is used for particle identification. The particle-species dependence of the
Cronin effect is observed to be significantly smaller than that at lower
energies. The ratio of the nuclear modification factor () between
protons and charged hadrons () in the transverse momentum
range GeV/c is measured to be
(stat)(syst) in minimum-bias collisions and shows little
centrality dependence. The yield ratio of in minimum-bias d+Au
collisions is found to be a factor of 2 lower than that in Au+Au collisions,
indicating that the Cronin effect alone is not enough to account for the
relative baryon enhancement observed in heavy ion collisions at RHIC.Comment: 6 pages, 4 figures, 1 table. We extended the pion spectra from
transverse momentum 1.8 GeV/c to 3. GeV/
Experimental and Theoretical Challenges in the Search for the Quark Gluon Plasma: The STAR Collaboration's Critical Assessment of the Evidence from RHIC Collisions
We review the most important experimental results from the first three years
of nucleus-nucleus collision studies at RHIC, with emphasis on results from the
STAR experiment, and we assess their interpretation and comparison to theory.
The theory-experiment comparison suggests that central Au+Au collisions at RHIC
produce dense, rapidly thermalizing matter characterized by: (1) initial energy
densities above the critical values predicted by lattice QCD for establishment
of a Quark-Gluon Plasma (QGP); (2) nearly ideal fluid flow, marked by
constituent interactions of very short mean free path, established most
probably at a stage preceding hadron formation; and (3) opacity to jets. Many
of the observations are consistent with models incorporating QGP formation in
the early collision stages, and have not found ready explanation in a hadronic
framework. However, the measurements themselves do not yet establish
unequivocal evidence for a transition to this new form of matter. The
theoretical treatment of the collision evolution, despite impressive successes,
invokes a suite of distinct models, degrees of freedom and assumptions of as
yet unknown quantitative consequence. We pose a set of important open
questions, and suggest additional measurements, at least some of which should
be addressed in order to establish a compelling basis to conclude definitively
that thermalized, deconfined quark-gluon matter has been produced at RHIC.Comment: 101 pages, 37 figures; revised version to Nucl. Phys.
Azimuthal anisotropy in Au+Au collisions at √s\u3csub\u3eNN\u3c/sub\u3e = 200 GeV
The results from the STAR Collaboration on directed flow (ν1), elliptic flow (ν2), and the fourth harmonic (ν4) in the anisotropic azimuthal distribution of particles from Au+Au collisions at √sNN=200GeV are summarized and compared with results from other experiments and theoretical models. Results for identified particles are presented and fit with a blast-wave model. Different anisotropic flow analysis methods are compared and nonflow effects are extracted from the data. For ν2, scaling with the number of constituent quarks and parton coalescence are discussed. For ν4, scaling with v22 and quark coalescence are discussed
Incident energy dependence of p\u3csub\u3et\u3c/sub\u3e correlations at relativistic energies
We present results for two-particle transverse momentum correlations, ⟨Δpt,iΔpt,j⟩, as a function of event centrality for Au+Au collisions at √sNN=20, 62, 130, and 200 GeV at the BNL Relativistic Heavy Ion Collider. We observe correlations decreasing with centrality that are similar at all four incident energies. The correlations multiplied by the multiplicity density increase with incident energy, and the centrality dependence may show evidence of processes such as thermalization, jet production, or the saturation of transverse flow. The square root of the correlations divided by the event-wise average transverse momentum per event shows little or no beam energy dependence and generally agrees with previous measurements made at the CERN Super Proton Synchrotron
Proton-Λ correlations in central Au+Au collisions at √s\u3csub\u3eNN\u3c/sub\u3e = 200 GeV
We report on p−Λ,p− ¯Λ¯ ,¯p¯−Λ, and ¯p¯− ¯Λ¯ correlation functions constructed in central Au-Au collisions at √sNN=200 GeV by the STAR experiment at RHIC. The proton and lambda source size is inferred from the p−Λ and p− ¯Λ¯; correlation functions. It is found to be smaller than the pion source size also measured by the STAR experiment at smaller transverse masses, in agreement with a scenario of a strong universal collective flow. The ¯p¯− Λ and p− ¯Λ¯ correlation functions, which are measured for the first time, exhibit a large anticorrelation. Annihilation channels and/or a negative real part of the spin-averaged scattering length must be included in the final-state interactions calculation to reproduce the measured correlation function
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