1,614 research outputs found

    The morphological discrimination of microfilariae of Onchocerca volvulus from Mansonella ozzardi.

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    There is no published account which allows the morphological discrimination of microfilariae of Onchocerca volvulus and M. ozzardi from each other. However, they occur together in parts of Brazil and Venezuela, and presumably there is always the possibility that migration could establish new sympatric populations in the future. The objective of this study was to evaluate simple morphological characters that might be used for species-diagnosis of microfilariae. The conclusions were that the location of microfilariae in the blood or skin, the body size and the nucleation of the nerve ring are expected to be useful first indications of species identity, but cannot be used for confident diagnosis. The structure of the cephalic armature (stained with alcian blue) seems to be species specific, but is of limited application because it is often difficult to see. However, the pattern of nucleation of the tail (as expressed by the ratio of the length of the terminal nucleus compared with the length of the tail space) is distinctive and is expected to be diagnostic

    pQCD vs. AdS/CFT Tested by Heavy Quark Energy Loss

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    We predict the charm and bottom quark nuclear modification factors using weakly coupled pQCD and strongly coupled AdS/CFT drag methods. The log(pT/M_Q)/pT dependence of pQCD loss and the momentum independence of drag loss lead to different momentum dependencies for the R_{AA} predictions. This difference is enhanced by examining a new experimental observable, the double ratio of charm to bottom nuclear modification factors, R^{cb}=R^c_{AA}/R^b_{AA}. At LHC the weakly coupled theory predicts R^{cb} goes to 1; whereas the strongly coupled theory predicts R^{cb} .2 independent of pT. At RHIC the differences are less dramatic, as the production spectra are harder, but the drag formula is applicable to higher momenta, due to the lower temperature.Comment: 6 pages, 4 figures. Proceedings for the International Conference on Strangeness in Quark Matter (SQM 2007), Levoca, Slovakia, 24-29 June 200

    Surprising Connections Between General Relativity and Condensed Matter

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    This brief review is intended to introduce gravitational physicists to recent developments in which general relativity is being used to describe certain aspects of condensed matter systems, e.g., superconductivity.Comment: 14 pages; based on talk given at GR1

    Gauge/Gravity Correspondence from Open/Closed String Duality

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    We compute the annulus diagram corresponding to the interaction of a fractional D3 brane with a gauge field on its world-volume and a stack of N fractional D3 branes on the orbifolds C^2 /Z_2 and C^3/Z_2 x Z_2. We show that its logarithmic divergence can be equivalently understood as due either to massless open string states circulating in the loop or to massless closed string states exchanged between two boundary states. This follows from the fact that, under open/closed string duality, massless states in the open and closed string channels are matched into each other without mixing with massive states. This explains why the perturbative properties of many gauge theories living on the worldvolume of less supersymmetric and nonconformal branes have been recently obtained from their corresponding supergravity solution.Comment: LaTeX, 28 page

    A scalar field instability of rotating and charged black holes in (4+1)-dimensional Anti-de Sitter space-time

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    We study the stability of static as well as of rotating and charged black holes in (4+1)-dimensional Anti-de Sitter space-time which possess spherical horizon topology. We observe a non-linear instability related to the condensation of a charged, tachyonic scalar field and construct "hairy" black hole solutions of the full system of coupled Einstein, Maxwell and scalar field equations. We observe that the limiting solution for small horizon radius is either a hairy soliton solution or a singular solution that is not a regular extremal solution. Within the context of the gauge/gravity duality the condensation of the scalar field describes a holographic conductor/superconductor phase transition on the surface of a sphere.Comment: 16 pages including 8 figures, v2: discussion on soliton solutions extended; v3: matches version accepted for publication in JHE

    Sampling the canonical phase from phase-space functions

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    We discuss the possibility of sampling exponential moments of the canonical phase from the s-parametrized phase space functions. We show that the sampling kernels exist and are well-behaved for any s>-1, whereas for s=-1 the kernels diverge in the origin. In spite of that we show that the phase space moments can be sampled with any predefined accuracy from the Q-function measured in the double-homodyne scheme with perfect detectors. We discuss the effect of imperfect detection and address sampling schemes using other measurable phase-space functions. Finally, we discuss the problem of sampling the canonical phase distribution itself.Comment: 10 pages, 7 figures, REVTe

    Hysteretic characteristics of a double stripline in the critical state

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    Analytical investigations of the critical state are carried out for a superconducting stripline consisting of two individual coplanar strips with an arbitrary distance between them. Two different cases are considered: a stripline with transport current and strips exposed to a perpendicular magnetic field. In the second case, the obtained solutions correspond to "fieldlike" (for unclosed strips) and "currentlike" (for a long rectangular superconducting loop) states in an isolated strip to which both a transport current and a magnetic field are applied with constant ratio.Comment: 8 pages, 6 figures. accepted by SS

    Pulsational frequencies of the eclipsing delta-Scuti star HD 172189

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    The eclipsing delta-Scuti star HD 172189 is a probable member of the open cluster IC 4756 and a promising candidate target for the CoRoT mission. The detection of pulsation modes is the first step in the asteroseismological study of the star. Further, the calculation of the orbital parameters of the binary system allows us to make a dynamical determination of the mass of the star, which works as an important constraint to test and calibrate the asteroseismological models. From a detailed frequency analysis of 210 hours of photometric data of HD 172189 obtained from the STEPHI XIII campaign we have identified six pulsation frequencies with a confidence level of 99% and a seventh with a 65% confidence level in the range between 100-300 uHz. In addiction, three eclipses were observed during the campaign, allowing us to improve the determination of the orbital period of the system.Comment: 6 pages, 7 figure

    Measurement of the degree of Polarization Entanglement Through Position Interference

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    We produce polarization entangled states with variable degree of entanglement for twin photons. Entanglement in polarization is coupled to entanglement in position that produces transverse coincidence interference fringes. We show both theoretically and experimentally that, due to this coupling, we can use the interference pattern to measure the polarization degree of entanglement.Comment: 5 figure

    A conical deficit in the AdS4/CFT3 correspondence

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    Inspired by the AdS/CFT correspondence we propose a new duality that allow the study of strongly coupled field theories living in a 2+1 conical space-time. Solving the 4-d Einstein equations in the presence of an infinite static string and negative cosmological constant we obtain a conical AdS4 space-time whose boundary is identified with the 2+1 cone found by Deser, Jackiw and 't Hooft. Using the AdS4/CFT3 correspondence we calculate retarded Green's functions of scalar operators living in the cone.Comment: v3, 14 pages. We reinterpret our results for the Green's functions in the con
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