23,462 research outputs found
Magnetic Component of Quark-Gluon Plasma is also a Liquid!
The so called magnetic scenario recently suggested in \cite{Liao_ES_mono}
emphasizes the role of monopoles in strongly coupled quark-gluon plasma (sQGP)
near/above the deconfinement temperature, and specifically predicts that they
help reduce its viscosity by the so called "magnetic bottle" effect. Arguments
for "magnetic liquid" in 1-2 based on lattice measurement of monopole
density were provided in \cite{Chernodub}. Here we present results for
monopole-(anti)monopole correlation functions from the same classical molecular
dynamics simulations, which are found to be in very good agreement with recent
lattice results \cite{D'Alessandro:2007su}. We show that the magnetic Coulomb
coupling does run in the direction to the electric one, as expected,
and it is roughly inverse of the asymptotic freedom formula for the electric
one. However, as decreases to , the magnetic coupling never gets weak,
with the plasma parameter always large enough (). This nicely agrees
with empirical evidences from RHIC experiments, implying that magnetic objects
cannot have large mean free path and should also form a good liquid with low
viscosity.Comment: 4 pages, 4 figures. All figs updated. Important changes and new
results included in v
Towards Semantic Fast-Forward and Stabilized Egocentric Videos
The emergence of low-cost personal mobiles devices and wearable cameras and
the increasing storage capacity of video-sharing websites have pushed forward a
growing interest towards first-person videos. Since most of the recorded videos
compose long-running streams with unedited content, they are tedious and
unpleasant to watch. The fast-forward state-of-the-art methods are facing
challenges of balancing the smoothness of the video and the emphasis in the
relevant frames given a speed-up rate. In this work, we present a methodology
capable of summarizing and stabilizing egocentric videos by extracting the
semantic information from the frames. This paper also describes a dataset
collection with several semantically labeled videos and introduces a new
smoothness evaluation metric for egocentric videos that is used to test our
method.Comment: Accepted for publication and presented in the First International
Workshop on Egocentric Perception, Interaction and Computing at European
Conference on Computer Vision (EPIC@ECCV) 201
Chiral magnetic wave at finite baryon density and the electric quadrupole moment of quark-gluon plasma in heavy ion collisions
Chiral Magnetic Wave (CMW) is a gapless collective excitation of quark-gluon
plasma in the presence of external magnetic field that stems from the interplay
of Chiral Magnetic (CME) and Chiral Separation Effects (CSE); it is composed by
the waves of the electric and chiral charge densities coupled by the axial
anomaly. We consider CMW at finite baryon density and find that it induces the
electric quadrupole moment of the quark-gluon plasma produced in heavy ion
collisions: the "poles" of the produced fireball (pointing outside of the
reaction plane) acquire additional positive electric charge, and the "equator"
acquires additional negative charge. We point out that this electric quadrupole
deformation lifts the degeneracy between the elliptic flows of positive and
negative pions leading to , and estimate the magnitude
of the effect.Comment: 4 pages, 3 figure
Multi-wavelength variability properties of Fermi blazar S5 0716+714
S5 0716+714 is a typical BL Lacertae object. In this paper we present the
analysis and results of long term simultaneous observations in the radio,
near-infrared, optical, X-ray and -ray bands, together with our own
photometric observations for this source. The light curves show that the
variability amplitudes in -ray and optical bands are larger than those
in the hard X-ray and radio bands and that the spectral energy distribution
(SED) peaks move to shorter wavelengths when the source becomes brighter, which
are similar to other blazars, i.e., more variable at wavelengths shorter than
the SED peak frequencies. Analysis shows that the characteristic variability
timescales in the 14.5 GHz, the optical, the X-ray, and the -ray bands
are comparable to each other. The variations of the hard X-ray and 14.5 GHz
emissions are correlated with zero-lag, so are the V band and -ray
variations, which are consistent with the leptonic models. Coincidences of
-ray and optical flares with a dramatic change of the optical
polarization are detected. Hadronic models do not have the same nature
explanation for these observations as the leptonic models. A strong optical
flare correlating a -ray flare whose peak flux is lower than the
average flux is detected. Leptonic model can explain this variability
phenomenon through simultaneous SED modeling. Different leptonic models are
distinguished by average SED modeling. The synchrotron plus synchrotron
self-Compton (SSC) model is ruled out due to the extreme input parameters.
Scattering of external seed photons, such as the hot dust or broad line region
emission, and the SSC process are probably both needed to explain the
-ray emission of S5 0716+714.Comment: 43 pages, 13 figures, 3 tables, to be appeared in Ap
A Case for Redundant Arrays of Hybrid Disks (RAHD)
Hybrid Hard Disk Drive was originally concepted by Samsung, which incorporates a Flash memory in a magnetic disk. The combined ultra-high-density benefits of magnetic storage and the low-power and fast read access of NAND technology inspires us to construct Redundant Arrays of Hybrid Disks (RAHD) to offer a possible alternative to today’s Redundant Arrays of Independent Disks (RAIDs) and/or Massive Arrays of Idle Disks (MAIDs). We first design an internal management system (including Energy-Efficient Control) for hybrid disks. Three traces collected from real systems as well as a synthetic trace are then used to evaluate the RAHD arrays. The trace-driven experimental results show: in the high speed mode, a RAHD outplays the purely-magnetic-disk-based RAIDs by a factor of 2.4–4; in the energy-efficient mode, a RAHD4/5 can save up to 89% of energy at little performance degradationPeer reviewe
A (p,q) Deformation of the Universal Enveloping Superalgebra U(osp(2/2))
We investigate a two parameter quantum deformation of the universal
enveloping orthosymplectic superalgebra U(osp(2/2)) by extending the
Faddeev-Reshetikhin-Takhtajan formalism to the supersymetric case. It is shown
that possesses a non-commutative, non-cocommutative Hopf
algebra structure. All the results are expressed in the standard form using
quantum Chevalley basis.Comment: 8 pages; IC/93/41
Renormalization Group Approach to Field Theory at Finite Temperature
Scalar field theory at finite temperature is investigated via an improved
renormalization group prescription which provides an effective resummation over
all possible non-overlapping higher loop graphs. Explicit analyses for the
lambda phi^4 theory are performed in d=4 Euclidean space for both low and high
temperature limits. We generate a set of coupled equations for the mass
parameter and the coupling constant from the renormalization group flow
equation. Dimensional reduction and symmetry restoration are also explored with
our improved approach.Comment: 29 pages, can include figures in the body of the text using epsf.st
Static Potentials and the Magnetic Component of QCD Plasma near
Static quark-anti-quark potential encodes important information on the
chromodynamical interaction between color charges, and recent lattice results
show its very nontrivial behavior near the deconfinement temperature . In
this paper we study such potential in the framework of the ``magnetic
scenario'' for the near Tc QCD plasma, and particularly focus on the linear
part (as quantified by its slope, the tension) in the potential as well as the
strong splitting between the free energy and internal energy. By using an
analytic ``ellipsoidal bag'' model, we will quantitatively relate the free
energy tension to the magnetic condensate density and relate the internal
energy tension to the thermal monopole density. By converting the lattice
results for static potential into density for thermal monopoles we find the
density to be very large around Tc and indicate at quantum coherence, in good
agreement with direct lattice calculation of such density. A few important
consequences for heavy ion collisions phenomenology will also be discussed.Comment: 10 pages, 6 figure
Endocervical glandular neoplasia associated with lobular endocervical glandular hyperplasia is HPV-independent and correlates with carbonic anhydrase-IX expression: a Gynaecological Oncology Group Study.
BackgroundLobular endocervical glandular hyperplasia (LEGH) is a rare lesion of the uterine cervix. It has been proposed that LEGH may represent a precursor lesion to a group of mucinous adenocarcinoma with gastric phenotype (GA) that is independent of high-risk human papillomavirus (H-HPV) infection. Carbonic anhydrase-IX (CA-IX) is highly expressed in conventional glandular lesions (CGLs). However, expression of CA-IX in LEGH or GA has not been studied.MethodsIn all, 12 CGLs, 7 LEGHs, 6 LEGHs with coexisting adenocarcinoma in situ (AIS, 3) and GA (3) were identified from Japanese women with a cytological diagnosis of atypical glandular cells of undetermined significance. Immunostaining was used to detect CA-IX and p16(INK)4(a) (hereafter termed p16) protein expression in the tissues and CA-IX protein expression in the Papanicolaou smears (PSs). Polymerase chain reaction was used to detect H-HPV DNA in liquid-based cytology.ResultsOut of 12 (83%) CGLs, 10 were positive with H-HPV and high levels of CA-IX expression were seen in all (100%) cases. P16 protein expression was observed in 11 out of 12 (92%) cases. None of the LEGHs, LEGHs with AIS or GA were positive for H-HPV and only 8 out of 13 (62%) showed focal weak (1+) p16 expression. In contrast, all cases (100%) exhibited strong CA-IX protein expression.ConclusionOur study suggests that there are different molecular mechanisms of carcinogenesis resulting in CGLs vs LEGHs associated with AIS or GA. There is also a possible link between LEGHs and GAs. Furthermore, CA-IX expression may serve as a useful biomarker for the detection of GAs in the absence of H-HPV infection
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