2,597 research outputs found
Chiral Condensate in Holographic QCD with Baryon Density
We consider the chiral condensate in the baryonic dense medium using the
generalized Sakai-Sugimoto model. It is defined as the vacuum expectation value
of open Wilson line that is proposed to be calculated by use of the area of
world-sheet instanton. We evaluate it in confined as well as deconfined phase.
In both phases, the chiral condensate has a minimum as a function of baryon
density. In the deconfined phase, taking into account the chiral symmetry
restoration, we classify the behavior of chiral condensate into three types.
One can set the parameter of the theory such that the results, in low but
sufficiently higher density, is in agreement with the expectation from QCD.Comment: 23 pages, 8 figure
Lepton-nucleus scattering in the impulse approximation regime
We discuss theoretical calculations of electron- and neutrino-nucleus
scattering, carried out using realistic nuclear spectral functions and
including the effect of final state interactions. Comparison between electron
scattering data and the calculated inclusive cross sections off oxygen shows
that the Fermi gas model fails to provide a satisfactory description of the
measured cross sections, and inclusion of nuclear dynamics is needed. The role
of Pauli blocking in charged-current neutrino induced reactions at low is
also analyzed.Comment: To be published in the Proceedings of NUFACT05 (Nucl. Phys. B,
Proceedings Supplements
Deciding Full Branching Time Logic by Program Transformation
We present a method based on logic program transformation, for verifying Computation Tree Logic (CTL*) properties of finite state reactive systems. The finite state systems and the CTL* properties we want to verify, are encoded as logic programs on infinite lists. Our verification method consists of two steps. In the first step we transform the logic program that encodes the given system and the given property, into a monadic ω -program, that is, a stratified program defining nullary or unary predicates on infinite lists. This transformation is performed by applying unfold/fold rules that preserve the perfect model of the initial program. In the second step we verify the property of interest by using a proof method for monadic ω-program
Winding effects on brane/anti-brane pairs
We study a brane/anti-brane configuration which is separated along a compact
direction by constructing a tachyon effective action which takes into account
transverse scalars. Such an action is relevant in the study of HQCD model of
Sakai and Sugimoto of chiral symmetry breaking, where the size of the compact
circle sets the confinement scale. Our approach is motivated by string theory
orbifold constructions and gives a route to model inhomogeneous tachyon decay.
We illustrate the techniques involved with a relatively simple example of a
harmonic oscillator on a circle. We will then repeat the analysis for the
Sakai-Sugimoto model and show that by integrating out the winding modes will
provide us with a renormalized action with a lower energy than that of
truncating to zero winding sector.Comment: 21 pages, 3 figures. v3: discussion and references added, published
versio
Optical Potential for the p-Shell Heavy Ion Scattering
開始ページ、終了ページ: 冊子体のページ付
Peristaltic Transport of a Couple Stress Fluid: Some Applications to Hemodynamics
The present paper deals with a theoretical investigation of the peristaltic
transport of a couple stress fluid in a porous channel. The study is motivated
towards the physiological flow of blood in the micro-circulatory system, by
taking account of the particle size effect. The velocity, pressure gradient,
stream function and frictional force of blood are investigated, when the
Reynolds number is small and the wavelength is large, by using appropriate
analytical and numerical methods. Effects of different physical parameters
reflecting porosity, Darcy number, couple stress parameter as well as amplitude
ratio on velocity profiles, pumping action and frictional force, streamlines
pattern and trapping of blood are studied with particular emphasis. The
computational results are presented in graphical form. The results are found to
be in good agreement with those of Shapiro et. al \cite{r25} that was carried
out for a non-porous channel in the absence of couple stress effect. The
present study puts forward an important observation that for peristaltic
transport of a couple stress fluid during free pumping when the couple stress
effect of the fluid/Darcy permeability of the medium, flow reversal can be
controlled to a considerable extent. Also by reducing the permeability it is
possible to avoid the occurrence of trapping phenomenon
Two Phase Model Analysis for the Stokes Flow past a Sphere Attached to the Circular Tube Wall
微小血管内では,血管壁近傍に赤血球がほとんど通らない領域が見られ,血漿層と呼ばれている.本研究では,細静脈壁に接着している白血球に血流が及ぼす剪断応力に対して,血漿層が与える影響をモデル解析によって調べた.血管を直円管,白血球を剛体球とし,血液の流れを血漿層と,赤血球が多数通過する中心層とからなる二層流と仮定して白血球周りの流れ場を数値的に解析した.その結果として,血漿層の効果によって白血球に作用する剪断応力は増加することが示された.\nThe blood flow past a leukocyte adhered to the microvessel wall is analyzed by a numerical simulation, taking the presence of a cell-free layer into account. The adherent leukocyte is modeled as a sphere attached to the wall of a circular cylindrical tube. The blood flow is modeled as a two-phase flow, consisting of a plasma flow in a cell-free layer adjacent to the vessel wall and the cell-rich flow in the central region of the vessel. It is assumed that each fluid in both regions is Newtonian with a uniform viscosity and that the viscosity of the cell-free layer is smaller than that of the central core. The interface between the two regions is assumed to be parallel to the streamlines. Numerical simulations by a finite element method have demonstrated that there are two different cases of the flow pattern around a sphere: one is a case where the whole sphere is embedded in the cell-free layer, and the other is a case where the sphere is covered by the central core. In both cases, the maximum magnitudes of the shear stress acting on the leukocyte are higher than those in the absence of the cell-free layer
Tunable gigahertz dynamics of low-temperature skyrmion lattice in a chiral magnet
Recently, it has been shown that the chiral magnetic insulator Cu2OSeO3hosts skyrmions in two separated pockets in temperature and magnetic field phase space. It has also been shown that the predominant stabilization mechanism for the low-temperature skyrmion (LTS) phase is via the crystalline anisotropy, opposed to temperature fluctuations that stabilize the well-established high-temperature skyrmion (HTS) phase. Here, we report on a detailed study of LTS generation by field cycling, probed by GHz spin dynamics in Cu2OSeO3. LTSs are populated via a field cycling protocol with the static magnetic field applied parallel to the ⟨100⟩ crystalline direction of plate and cuboid-shaped bulk crystals. By analyzing temperature-dependent broadband spectroscopy data, clear evidence of LTS excitations with clockwise (CW), counterclockwise (CCW), and breathing mode (BR) character at temperatures belowT= 40 K are shown. We find that the mode intensities can be tuned with the number of field-cycles below the saturation field. By tracking the resonance frequencies, we are able to map out the field-cycle-generated LTS phase diagram, from which we conclude that the LTS phase is distinctly separated from the high-temperature counterpart. We also study the mode hybridization between the dark CW and the BR modes as a function of temperature. By using two Cu2OSeO3crystals with different shapes and therefore different demagnetization factors, together with numerical calculations, we unambiguously show that the magnetocrystalline anisotropy plays a central role for the mode hybridization
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Aspirin-Trigge red-Resolvin D1 reduces mucosal inflammation and promotes resolution in a murine model of acute lung injury
Acute Lung Injury (ALI) is a severe illness with excess mortality and no specific therapy. Protective actions were recently uncovered for docosahexaenoic acid -derived mediators, including D-series resolvins. Here, we used a murine self-limited model of hydrochloric acid-induced ALI to determine the effects of aspirin-triggered resolvin D1 (AT-RvD1) on mucosal injury. RvD1 and its receptor ALX/FPR2 were identified in murine lung after ALI. AT-RvD1 (~0.5 – 5 μg/kg) decreased peak inflammation, including bronchoalveolar lavage fluid (BALF) neutrophils by ~75%. Animals treated with AT-RvD1 had improved epithelial and endothelial barrier integrity and decreased airway resistance concomitant with increased BALF epinephrine levels. AT-RvD1 inhibited neutrophil-platelet heterotypic interactions by down-regulating both P-selectin and its ligand CD24. AT-RvD1 also significantly decreased levels of BALF pro-inflammatory cytokines, including IL-1β, IL-6, KC and TNF-α, and decreased NF-κB phosphorylated p65 nuclear translocation. Together, these findings indicate that AT-RvD1 displays potent mucosal protection and promotes catabasis after ALI
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