2,979 research outputs found

    Stimulated Raman Adiabatic Passage via bright state in Lambda medium of unequal oscillator strengths

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    We consider the population transfer process in a Lambda-type atomic medium of unequal oscillator strengths by stimulated Raman adiabatic passage via bright-state (b-STIRAP) taking into account propagation effects. Using both analytic and numerical methods we show that the population transfer efficiency is sensitive to the ratio q_p/q_s of the transition oscillator strengths. We find that the case q_p>q_s is more detrimental for population transfer process as compared to the case where qp≀qsq_p \leq q_s. For this case it is possible to increase medium dimensions while permitting efficient population transfer. A criterion determining the interaction adiabaticity in the course of propagation process is found. We also show that the mixing parameter characterizing the population transfer propagates superluminally

    PQChPT with Staggered Sea and Valence Ginsparg-Wilson Quarks: Vector Meson Masses

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    We consider partially quenched, mixed chiral perturbation theory with staggered sea and Ginsparg-Wilson valence quarks in order to extract a chiral-continuum extrapolation expression for the vector meson mass up to order O(a^2), at one-loop level. Based on general principles, we accomplish the task without explicitly constructing a sophisticated, heavy vector meson chiral Lagrangian.Comment: 12 pages, 1 figure, REVTe

    Regge description of spin-spin asymmetry in photon diffractive dissociation

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    We explore the possibility whether the gluon helicity distribution ΔG(x)\Delta G(x) can be extracted from a comparison of experimental data on the longitudinal spin-spin asymmetry ALLA_{LL} in Îłp\gamma p diffractive deep inelastic scattering with calculations performed within the framework of perturbative QCD (pQCD). The data could be obtained at the future HERA collider in scattering of polarized electrons/positrons off polarized protons. In this paper we look for such kinematical regions where contributions to ALLA_{LL} from soft processes (reggeon exchanges) are suppressed to guarantee an applicability of pQCD. It is shown that for the square of the center-of-mass energy sÎłp≄103GeV2s_{\gamma p} \geq 10^3 GeV^2, the hadronic diffractive mass MX≀10GeV/c2M_X \leq 10 GeV/c^2, the momentum transferred to the proton ΔT≀0.5GeV/c\Delta_T\leq 0.5 GeV/c, and Q2≄4(GeV/c)2Q^2\geq4 (GeV/c)^2 the longitudinal spin-spin asymmetry due to reggeon exchanges is less than 10^{-4}. This value is presumably lower than the asymmetry which can be measured with modern experimental technique. This means that the pQCD prediction can be reliably compared with data in this kinematical region.Comment: 44 pages, LaTeX, 12 figure

    Infinite-dimensional Compact Quantum Semigroup

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    In this paper we construct a compact quantum semigroup structure on the Toeplitz algebra T\mathcal{T}. The existence of a subalgebra, isomorphic to the algebra of regular Borel's measures on a circle with convolution product, in the dual algebra T∗\mathcal{T}^* is shown. The existence of Haar functionals in the dual algebra and in the above-mentioned subalgebra is proved. Also we show the connection between T\mathcal{T} and the structure of weak Hopf algebra.Comment: 17 page

    Linear Confinement for Mesons and Nucleons in AdS/QCD

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    By using a new parametrization of the dilaton field and including a cubic term in the bulk scalar potential, we realize linear confinement in both meson and nucleon sectors within the framework of soft-wall AdS/QCD. At the same time this model also correctly incorporate chiral symmetry breaking. We compare our resulting mass spectra with experimental data and find good agreement between them.Comment: 14 pages, published version in JHE

    Short-length storage of intense optical pulses in solid by adiabatic passage

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    We propose a novel scheme of storage of intense pulses which allows a significant reduction of the storage length with respect to standard schemes. This scheme is particularly adapted to store optical information in media with fast relaxations.Comment: 7 pages, 5 figure

    Instabilities of dispersion-managed solitons in the normal dispersion regime

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    Dispersion-managed solitons are reviewed within a Gaussian variational approximation and an integral evolution model. In the normal regime of the dispersion map (when the averaged path dispersion is negative), there are two solitons of different pulse duration and energy at a fixed propagation constant. We show that the short soliton with a larger energy is linearly (exponentially) unstable. The other (long) soliton with a smaller energy is linearly stable but hits a resonance with excitations of the dispersion map. The results are compared with the results from the recent publicationsComment: 20 figures, 20 pages. submitted to Phys. Rev.

    The prognostic value of ferritinemia level in patients with chronic hepatitis C

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    Aim of investigation. To study the effect of various factors on the blood ferritin level in patients with chronic hepatitis C (CHC) and baseline ferritin level on treatment response rate of pegilated interferon α-2a (PEG-IFN α-2a) combined to ribavirin (RBV). Material and methods. The level of ferritin was determined in 67 patients with CHC by two solid-phase sandwich immunoenzymatic assays. In 32 patients, who received PEG-IFN α-2a and RBV, it was determined on starting point, on the 12th week and after termination of therapy. Logistical regression has been applied to study effect of ferritin and other variables on frequency of sustained virologic response (SVR). Results. Elevated ferritin level was revealed in 34,3% of patients, and it was significantly higher in men, than in women (326,0±38,4 vs 108,2±44,7 ng/dl, p <0,05). The average level of ferritin in the patients included in PEGIFN α-2a and RBV group, prior to onset of treatment was normal (241,4±33,1), on the 12th week of treatment it turn to be elevated in 90% of patients with average level of 703,5±133,4 ng/dl (p=0,009 at comparison to initial level), and after the end of treatment course elevation was observed in 66,6% of patients at average value of 473,6±96,3 ng/dl (p=0,044 at to starting point, p=0,07 at comparison to the 12-th week data). By comparison of average levels of ferritin in patients with SVR at intake of PEG-IFN α-2a in combination to RBV and in patients without SVR the difference was also apparent, especially at the 12th week.Conclusions. Application of logistical regression analysis demonstrated, that the baseline ferritin level is independent predictor of sustained virologic response at treatment by pegilated interferon α-2a with ribavirin

    Loss of epidermal Evi/Wls results in a phenotype resembling psoriasiform dermatitis

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    Cells of the epidermis renew constantly from germinal layer stem cells. Although epithelial cell differentiation has been studied in great detail and the role of Wnt signaling in this process is well described, the contribution of epidermal Wnt secretion in epithelial cell homeostasis remains poorly understood. To analyze the role of Wnt proteins in this process, we created a conditional knockout allele of the Wnt cargo receptor Evi/Gpr177/Wntless and studied mice that lacked Evi expression in the epidermis. We found that K14-Cre, Evi-LOF mice lost their hair during the first hair cycle, showing a reddish skin with impaired skin barrier function. Expression profiling of mutant and wild-type skin revealed up-regulation of inflammation-associated genes. Furthermore, we found that Evi expression in psoriatic skin biopsies is down-regulated, suggesting that Evi-deficient mice developed skin lesions that resemble human psoriasis. Immune cell infiltration was detected in Evi-LOF skin. Interestingly, an age-dependent depletion of dendritic epidermal T cells (DETCs) and an infiltration of gammadelta(low) T cells in Evi mutant epidermis was observed. Collectively, the described inflammatory skin phenotype in Evi-deficient mice revealed an essential role of Wnt secretion in maintaining normal skin homeostasis by enabling a balanced epidermal-dermal cross talk, which affects immune cell recruitment and DETC survival
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