Logarithmic perturbation theory for quasinormal modes

Logarithmic perturbation theory (LPT) is developed and applied to quasinormal modes (QNMs) in open systems. QNMs often do not form a complete set, so LPT is especially convenient because summation over a complete set of unperturbed states is not required. Attention is paid to potentials with exponential tails, and the example of a Poschl-Teller potential is briefly discussed. A numerical method is developed that handles the exponentially large wavefunctions which appear in dealing with QNMs.Comment: 24 pages, 4 Postscript figures, uses ioplppt.sty and epsfig.st

Hemophilic patient for emergency spinal decompression

Hemophilia is mostly an inherited genetic disorder, caused by mutations in the clotting factor gene. With the available treatment options, life expectancy of a hemophilic patient is usually of that of the general population. Hence, it is not uncommon that they present for surgical procedures. However, hemophilic patients for the major surgical procedure are always a real challenge for the perioperative physician. We have recently encountered one such patient who was hospitalized with acute paraplegia due to a mass lesion of spine and successfully managed with the recovery of motor power. His pre-operative Factor VIII level was 0. Desmopressin nasal spray has a limited role in severe hemophilic. Our main concern was effective replacement therapy and maintenance of desired Factor VIII levels not only during surgery but also in the immediate post-operative period

Perturbative Approach to the Quasinormal Modes of Dirty Black Holes

Using a recently developed perturbation theory for uasinormal modes (QNM's), we evaluate the shifts in the real and imaginary parts of the QNM frequencies due to a quasi-static perturbation of the black hole spacetime. We show the perturbed QNM spectrum of a black hole can have interesting features using a simple model based on the scalar wave equation.Comment: Published in PR

Quasinormal Modes of Dirty Black Holes

Quasinormal mode (QNM) gravitational radiation from black holes is expected to be observed in a few years. A perturbative formula is derived for the shifts in both the real and the imaginary part of the QNM frequencies away from those of an idealized isolated black hole. The formulation provides a tool for understanding how the astrophysical environment surrounding a black hole, e.g., a massive accretion disk, affects the QNM spectrum of gravitational waves. We show, in a simple model, that the perturbed QNM spectrum can have interesting features.Comment: 4 pages. Published in PR

Duality and Symmetry in Chiral Potts Model

We discover an Ising-type duality in the general $N$-state chiral Potts model, which is the Kramers-Wannier duality of planar Ising model when N=2. This duality relates the spectrum and eigenvectors of one chiral Potts model at a low temperature (of small $k'$) to those of another chiral Potts model at a high temperature (of $k'^{-1}$). The $\tau^{(2)}$-model and chiral Potts model on the dual lattice are established alongside the dual chiral Potts models. With the aid of this duality relation, we exact a precise relationship between the Onsager-algebra symmetry of a homogeneous superintegrable chiral Potts model and the $sl_2$-loop-algebra symmetry of its associated spin-$\frac{N-1}{2}$ XXZ chain through the identification of their eigenstates.Comment: Latex 34 pages, 2 figures; Typos and misprints in Journal version are corrected with minor changes in expression of some formula

Symmetries of Large N Matrix Models for Closed Strings

We obtain the symmetry algebra of multi-matrix models in the planar large N limit. We use this algebra to associate these matrix models with quantum spin chains. In particular, certain multi-matrix models are exactly solved by using known results of solvable spin chain systems.Comment: 12 pages, 1 eps figure, RevTex, some minor typos in the publised version are correcte

BOVA is Superior to sPESI in Identification of High Risk Pulmonary Embolism Patients

Introduction: Prognostic models exist for the purpose of stratifying patients with acute pulmonary embolism. Of these, the Pulmonary Embolism Severity Index (PESI) and the simplified PESI (sPESI) are the most well-known, although more recent composite models, like the BOVA score, are now being studied and implemented. Comparative efficacy of these scores to predict long term mortality is not well established. Methods: We performed a retrospective analysis of all consecutive patients diagnosed with PE using computed tomography scan from 2014-2016 at an urban tertiary-referral medical center. Cox proportional hazard analyses were performed to compare the performance of two prognostic models – sPESI and BOVA – to predict all-cause in-hospital and cumulative one-year mortality. Results: The all-cause in-hospital mortality rate was 6.0%, and cumulative one-year mortality rate was 21.3%. In adjusted analyses, a BOVA score \u3e4 was significantly associated with an increased in-hospital mortality (HR 3.5, 95% CI: 1.4-9.0, p = 0.009) and one-year mortality (HR 2.0, 95% CI: 1.0-3.9, p = 0.04), as compared to a BOVA score \u3c4. However, the sPESI (p = 0.14) did not show a significant association with one-year mortality. In identifying in-hospital mortality, the sPESI had high sensitivity (100%) and low specificity (10.1%), whereas the BOVA score had low sensitivity (20.0%) and high specificity (92.7%). Similar trends were seen for one-year mortality. Conclusion: In this study, a high BOVA score was found to be the best predictor of both short and long-term mortality in PE patients. A low sPESI score identified with high sensitivity patients with low-risk PEs

Reverberation Mapping Measurements of Black Hole Masses in Six Local Seyfert Galaxies

We present the final results from a high sampling rate, multi-month, spectrophotometric reverberation mapping campaign undertaken to obtain either new or improved Hbeta reverberation lag measurements for several relatively low-luminosity AGNs. We have reliably measured thetime delay between variations in the continuum and Hbeta emission line in six local Seyfert 1 galaxies. These measurements are used to calculate the mass of the supermassive black hole at the center of each of these AGNs. We place our results in context to the most current calibration of the broad-line region (BLR) R-L relationship, where our results remove outliers and reduce the scatter at the low-luminosity end of this relationship. We also present velocity-resolved Hbeta time delay measurements for our complete sample, though the clearest velocity-resolved kinematic signatures have already been published.Comment: 52 pages (AASTeX: 29 pages of text, 8 tables, 7 figures), accepted for publication in the Astrophysical Journa

On τ(2)\tau^{(2)}-model in Chiral Potts Model and Cyclic Representation of Quantum Group Uq(sl2)U_q(sl_2)

We identify the precise relationship between the five-parameter $\tau^{(2)}$-family in the $N$-state chiral Potts model and XXZ chains with $U_q (sl_2)$-cyclic representation. By studying the Yang-Baxter relation of the six-vertex model, we discover an one-parameter family of $L$-operators in terms of the quantum group $U_q (sl_2)$. When $N$ is odd, the $N$-state $\tau^{(2)}$-model can be regarded as the XXZ chain of $U_{\sf q} (sl_2)$ cyclic representations with ${\sf q}^N=1$. The symmetry algebra of the $\tau^{(2)}$-model is described by the quantum affine algebra $U_{\sf q} (\hat{sl}_2)$ via the canonical representation. In general for an arbitrary $N$, we show that the XXZ chain with a $U_q (sl_2)$-cyclic representation for $q^{2N}=1$ is equivalent to two copies of the same $N$-state $\tau^{(2)}$-model.Comment: Latex 11 pages; Typos corrected, Minor changes for clearer presentation, References added and updated-Journal versio

Surface Critical Phenomena and Scaling in the Eight-Vertex Model

We give a physical interpretation of the entries of the reflection $K$-matrices of Baxter's eight-vertex model in terms of an Ising interaction at an open boundary. Although the model still defies an exact solution we nevertheless obtain the exact surface free energy from a crossing-unitarity relation. The singular part of the surface energy is described by the critical exponents $\alpha_s = 2 - \frac{\pi}{2\mu}$ and $\alpha_1 = 1 - \frac{\pi}{\mu}$, where $\mu$ controls the strength of the four-spin interaction. These values reduce to the known Ising exponents at the decoupling point $\mu=\pi/2$ and confirm the scaling relations $\alpha_s = \alpha_b + \nu$ and $\alpha_1 = \alpha_b -1$.Comment: 12 pages, LaTeX with REVTEX macros needed. To appear in Physical Review Letter