13,623 research outputs found

    Matched-filtering and parameter estimation of ringdown waveforms

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    Using recent results from numerical relativity simulations of non-spinning binary black hole mergers we revisit the problem of detecting ringdown waveforms and of estimating the source parameters, considering both LISA and Earth-based interferometers. We find that Advanced LIGO and EGO could detect intermediate-mass black holes of mass up to about 1000 solar masses out to a luminosity distance of a few Gpc. For typical multipolar energy distributions, we show that the single-mode ringdown templates presently used for ringdown searches in the LIGO data stream can produce a significant event loss (> 10% for all detectors in a large interval of black hole masses) and very large parameter estimation errors on the black hole's mass and spin. We estimate that more than 10^6 templates would be needed for a single-stage multi-mode search. Therefore, we recommend a "two stage" search to save on computational costs: single-mode templates can be used for detection, but multi-mode templates or Prony methods should be used to estimate parameters once a detection has been made. We update estimates of the critical signal-to-noise ratio required to test the hypothesis that two or more modes are present in the signal and to resolve their frequencies, showing that second-generation Earth-based detectors and LISA have the potential to perform no-hair tests.Comment: 19 pages, 9 figures, matches version in press in PR

    Orientation in the diagnosis of intraocular neoplasia, through intraocular fine needle aspiration (IFNA)

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    IFNA is a safe diagnostic technique that allows diagnostic of neoplastic and inflammatory processes of the eye1. In cats melanoma is common in the eye, skin and oral cavity2. In the eyep, local infiltration to systemic metastases may occur2. Being, the IFNA a method that assists in the diagnosis and therapeutics1,3,4,5. An european female cat, seven years old, was presented to consultation with brown patches of progressive growth in the right iris for four months. The pupillary light reflex, dazzle and menace response were present, and the ocular echography showed an area with iris thickening and with hyperechogenicity1. Due to clinical suspicion of iris melanoma, it was requested radiographic examination of the thorax, abdominal ultrasonography, hematological and biochemical blood analysis1,2, revealing no alterations. The IFNA was performed under general anesthesia introducing the a 26 gauge needle near the limbus and directed to the iris lesion with the bevel facing the surface of the mass3,4. The technique was performed without complications. The cytology using hematoxylin and eosin staining revealed moderate cellularity composed of rounded cells with moderate nuclear pleomorphism, bulky, pale cytoplasm1. The atypical round cells were suggestive of round cell amelanotic melanoma. Due to the cytological orientation, the enucleation of right eye was advised to the owner, which was declined.The diagnosis of ocular melanoma can be directed on clinical grounds and confirmed by anatomopathological exams2. IFNA is a practical, method in aiding the differentiation of neoplastic from non-neoplastic processes. It also helps guiding the surgical procedure and establishing prognosis1,3,4,5

    LAMELAR CORNEAL TRANSPLANTATION IN A DOG FOR SURGICAL TREATMENT OF CORNEA DEEP ULCER WITH DESCEMETOCELE.

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    Corneal transplantation is a procedure indicated for surgical treatment of several corneal diseases, requiring replacement of the affected tissues1,2,3,4. A dog of undefined breed, 5 years old, revealed on ocular examination, a deep corneal ulcer and a Descemet\'s membrane (DM) exposure. Aiming at corneal repair, the surgical technique of lamellar corneal transplantation was used. The perimeter of the transplant was defined with the help of a biopsy punch. With a 1 ml syringe and a 26 G” needle, air was injected into the deep corneal stroma in order to separate DM from stroma1,2. Subsequently paracentesis was performed to reduce ocular pressure and a small air bubble was added in order to help the corneal depthness perspective. With a crescent knife, excision of the compromised tissue was performed1,3. The DM was covered using cryopreserved canine cornea4 at -20°C in 3mg/ml tobramycin solution and thawed at room temperature it was also molded obtaining the appropriate sized tissue for the recoil1. The corneal suture was made using simple isolated points with 8-0 polyglactin and for corneal protection a third eyelid flap was performed1,3. Topical moxifloxacin, tropicamide, EDTA and autologous serum were used in post-surgical treatment3. The third eyelid flap was removed at 15 days post-surgery and a complete corneal repair was observed with total incorporation in the recipient cornea. Lamellar corneal transplantation employing cryopreserved cornea in tobramycin solution has been shown to be effective in the surgical treatment of descemetocele when related to other techniques1,3,4

    The holographic RG flow in a field theory on a curved background

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    As shown by Freedman, Gubser, Pilch and Warner, the RG flow in N=4{\cal N}=4 super-Yang-Mills theory broken to an N=1{\cal N}=1 theory by the addition of a mass term can be described in terms of a supersymmetric domain wall solution in five-dimensional N=8{\cal N}=8 gauged supergravity. The FGPW flow is an example of a holographic RG flow in a field theory on a flat background. Here we put the field theory studied by Freedman, Gubser, Pilch and Warner on a curved AdS4AdS_4 background, and we construct the supersymmetric domain wall solution which describes the RG flow in this field theory. This solution is a curved (non Ricci flat) domain wall solution. This example demonstrates that holographic RG flows in supersymmetric field theories on a curved AdS4AdS_4 background can be described in terms of curved supersymmetric domain wall solutions.Comment: 14 pages, LaTe

    Pseudo-Supersymmetry and the Domain-Wall/Cosmology Correspondence

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    The correspondence between domain-wall and cosmological solutions of gravity coupled to scalar fields is explained. Any domain wall solution that admits a Killing spinor is shown to correspond to a cosmology that admits a pseudo-Killing spinor: whereas the Killing spinor obeys a Dirac-type equation with hermitian `mass'-matrix, the corresponding pseudo-Killing spinor obeys a Dirac-type equation with a anti-hermitian `mass'-matrix. We comment on some implications of (pseudo)supersymmetry.Comment: 11 pages, contribution to the proceedings of IRGAC 2006;v3: minor change

    On Quantum Special Kaehler Geometry

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    We compute the effective black hole potential V of the most general N=2, d=4 (local) special Kaehler geometry with quantum perturbative corrections, consistent with axion-shift Peccei-Quinn symmetry and with cubic leading order behavior. We determine the charge configurations supporting axion-free attractors, and explain the differences among various configurations in relations to the presence of ``flat'' directions of V at its critical points. Furthermore, we elucidate the role of the sectional curvature at the non-supersymmetric critical points of V, and compute the Riemann tensor (and related quantities), as well as the so-called E-tensor. The latter expresses the non-symmetricity of the considered quantum perturbative special Kaehler geometry.Comment: 1+43 pages; v2: typo corrected in the curvature of Jordan symmetric sequence at page 2

    Entanglement versus mixedness for coupled qubits under a phase damping channel

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    Quantification of entanglement against mixing is given for a system of coupled qubits under a phase damping channel. A family of pure initial joint states is defined, ranging from pure separable states to maximally entangled state. An ordering of entanglement measures is given for well defined initial state amount of entanglement.Comment: 9 pages, 2 figures. Replaced with final published versio

    Bent-Double Radio Sources as Probes of Intergalactic Gas

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    As the most common environment in the universe, groups of galaxies are likely to contain a significant fraction of the missing baryons in the form of intergalactic gas. The density of this gas is an important factor in whether ram pressure stripping and strangulation affect the evolution of galaxies in these systems. We present a method for measuring the density of intergalactic gas using bent-double radio sources that is independent of temperature, making it complementary to current absorption line measurements. We use this method to probe intergalactic gas in two different environments: inside a small group of galaxies as well as outside of a larger group at a 2 Mpc radius and measure total gas densities of 4±1−2+6×10−34 \pm 1_{-2}^{+6} \times 10^{-3} and 9±3−5+10×10−49 \pm 3_{-5}^{+10} \times 10^{-4} per cubic centimeter (random and systematic errors) respectively. We use X-ray data to place an upper limit of 2×1062 \times 10^6 K on the temperature of the intragroup gas in the small group.Comment: 6 pages, 1 figure, accepted for publication in Ap

    Nernst branes from special geometry

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    We construct new black brane solutions in U(1)U(1) gauged N=2{\cal N}=2 supergravity with a general cubic prepotential, which have entropy density s∌T1/3s\sim T^{1/3} as T→0T \rightarrow 0 and thus satisfy the Nernst Law. By using the real formulation of special geometry, we are able to obtain analytical solutions in closed form as functions of two parameters, the temperature TT and the chemical potential ÎŒ\mu. Our solutions interpolate between hyperscaling violating Lifshitz geometries with (z,Ξ)=(0,2)(z,\theta)=(0,2) at the horizon and (z,Ξ)=(1,−1)(z,\theta)=(1,-1) at infinity. In the zero temperature limit, where the entropy density goes to zero, we recover the extremal Nernst branes of Barisch et al, and the parameters of the near horizon geometry change to (z,Ξ)=(3,1)(z,\theta)=(3,1).Comment: 37 pages. v2: numerical pre-factors of scalar fields q_A corrected in Section 3. No changes to conclusions. References adde
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