3,482 research outputs found

    Metal-nonmetal transition in LixCoO2 thin film and thermopower enhancement at high Li concentration

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    We investigate the transport properties of LixCoO2 thin films whose resistivities are nearly an order of magnitude lower than those of the bulk polycrystals. A metal-nonmetal transition occurs at ~0.8 in a biphasic domain, and the Seebeck coefficient (S) is drastically increased at ~140 K (= T*) with increasing the Li concentration to show a peak of magnitude ~120 \muV/K in the S-T curve of x = 0.87. We show that T* corresponds to a crossover temperature in the conduction, most likely reflecting the correlation-induced temperature dependence in the low-energy excitations

    Composition of primary cosmic rays at energies 10(15) to approximately 10(16) eV

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    The sigma epsilon gamma spectrum in 1 approx. 5 x 1000 TV observed at Mt. Fuji suggests that the flux of primary protons 10 to the 15 approx 10th eV is lower by a factor of 2 approx. 3 than a simple extrapolation from lower energies; the integral proton spectrum tends to be steeper than around to the power V and the spectral index tends to be steeper than Epsilon to the -17th power around 10 to the 14th power eV and the spectral index becomes approx. 2.0 around 10 to the 15th power eV. If the total flux of primary particles has no steepening up to approx 10 to the 15th power eV, than the fraction of primary protons to the total flux should be approx 20% in contrast to approx 45% at lower energies

    High energy gamma-rays and hadrons at Mount Fuji

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    The energy spectra of high energy gamma-rays and hadrons were obtained by the emulsion chamber with 40 c.u. thickness at Mt. Fuji (3750 m). These results are compared with the Monte Carlo calculation based on the same model which is used in a family analysis. Our data are compatible with the model of heavy-enriched primary and scaling in the fragmentation region

    Particle interactions at energies over 1000 TeV inferred from gamma-families observed at Mount Fuji

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    Scaling, mean P sub t, high P sub t jets and others at energies over 1000 TeV are discussed on the basis of gamma-family data with sigma E sub gamma 100 TeV, observed at Mt. Fuji (3750 m). These quantities were examined in connection with the primary composition

    Faddeev-chiral unitary approach to the K(-)d scattering length

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    Our earlier Faddeev three-body study in the K--deuteron scattering length, AK-d, is revisited here in light of the recent developments on two fronts: (i) the improved chiral unitary approach to the theoretical description of the coupled K̄N related channels at low energies, and (ii) the new and improved measurement from SIDDHARTA Collaboration of the strong interaction energy shift and width in the lowest K --hydrogen atomic level. Those two, in combination, have allowed us to produce a reliable two-body input to the three-body calculation. All available low-energy K-p observables are well reproduced and predictions for the K̄N scattering lengths and amplitudes, (πΣ)â̂̃ invariant-mass spectra, as well as for AK-d are put forward and compared with results from other sources. The findings of the present work are expected to be useful in interpreting the forthcoming data from CLAS, HADES, LEPS, and SIDDHARTA Collaborations. © 2013 American Physical Society.T. Mizutani, C. Fayard, B. Saghai, K. Tsushim

    A new ultra high energy gamma ray telescope at Ohya mine

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    The search for ultra high energy gamma rays coming from point sources is one of the main experimental aims. A fast air shower timing system was constructed at ICRR for the study of the angular resolution of the system and operated approximately half a year. The characteristics of the surface array of Ohya air shower telescope is described

    Suppressive activity of a macrolide antibiotic, roxithromycin, on pro-inflammatory cytokine production in vitro and in vivo.

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    This study was designed to examine the influence of a macrolide antibiotic, roxithromycin (RXM), on the production of pro-inflammatory cytokines, interleukin (IL)-1beta and tumor necrosis factor (TNF)-alpha. In the first experiments, we examined the effect of RXM on in vitro cytokine production from lipopolysaccharide (LPS)-stimulated human peripheral blood monocytes. The monocytes were cultured in the presence of various doses of the agent. After 24 h, the culture supernatants were obtained and assayed for IL-1beta and TNF-alpha contents by enzyme-linked immunosorbent assay. RXM suppressed the in vitro production of IL-1beta and TNF-alpha in response to LPS stimulation. This was dose dependent and first noted at a concentration of as little as 0.05 microg/ml, which is much lower than therapeutic blood levels. In the second part of the experiments, we examined the influence of RXM on the appearance of IL-1beta and TNF-alpha in mouse lung extract induced by LPS inhalation. RXM was administered orally into BALB/c mice at a single dose of 2.5 mg/kg once a day for 5-12 weeks. These mice were then instilled with LPS into the trachea and examined for the presence of cytokines in aqueous lung extracts. Pretreatment of mice with RXM for 5 weeks did not influence of the appearance of both IL-1beta and TNF-alpha in aqueous lung extracts. However, pretreatment for more than 7 weeks dramatically suppressed the cytokine appearance in the extracts

    Coherent quasi-particles-to-incoherent hole-carriers crossover in underdoped cuprates

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    In underdoped cuprates, only a portion of the Fermi surface survives as Fermi arcs due to pseudogap opening. In hole-doped La2_{2}CuO4_4, we have deduced the "coherence temperature" TcohT_{coh} of quasi-particles on the Fermi arc above which the broadened leading edge position in angle-integrated photoemission spectra is shifted away from the Fermi level and the quasi-particle concept starts to lose its meaning. TcohT_{coh} is found to rapidly increase with hole doping, an opposite behavior to the pseudogap temperature TT^*. The superconducting dome is thus located below both TT^* and TcohT_{coh}, indicating that the superconductivity emerges out of the coherent Fermionic quasi-particles on the Fermi arc. TcohT_{coh} remains small in the underdoped region, indicating that incoherent charge carriers originating from the Fermi arc are responsible for the apparently metallic transport at high temperatures

    Projectile Δ\Delta Excitations in p(p,n)Nπp(p,n)N\pi Reactions

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    It has recently been proven from measurements of the spin-transfer coefficients DxxD_{xx} and DzzD_{zz} that there is a small but non-vanishing ΔS=0\Delta S=0 component σ0\sigma_{0}, in the inclusive p(p,n)Nπp(p,n)N\pi\, reaction cross section σ\sigma\,. It is shown that the dominant part of the measured σ0\sigma_{0} can be explained in terms of the projectile Δ\Delta excitation mechanism. An estimate is further made of contributions to σ0\sigma_{0} from s-wave rescattering process. It is found that s-wave rescattering contribution is much smaller than the contribution coming from projectile Δ\Delta excitation mechanism. The addition of s-wave rescattering contribution to the dominant part, however, improves the fit to the data.Comment: 9 pages, Revtex, figures can be obtained upon reques

    Pruning Algorithms for Pretropisms of Newton Polytopes

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    Pretropisms are candidates for the leading exponents of Puiseux series that represent solutions of polynomial systems. To find pretropisms, we propose an exact gift wrapping algorithm to prune the tree of edges of a tuple of Newton polytopes. We prefer exact arithmetic not only because of the exact input and the degrees of the output, but because of the often unpredictable growth of the coordinates in the face normals, even for polytopes in generic position. We provide experimental results with our preliminary implementation in Sage that compare favorably with the pruning method that relies only on cone intersections.Comment: exact, gift wrapping, Newton polytope, pretropism, tree pruning, accepted for presentation at Computer Algebra in Scientific Computing, CASC 201
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