Quasinormal modes of a Schwarzschild black hole surrounded by free static spherically symmetric quintessence: Electromagnetic perturbations

In this paper, we evaluated the quasinormal modes of electromagnetic perturbation in a Schwarzschild black hole surrounded by the static spherically symmetric quintessence by using the third-order WKB approximation when the quintessential state parameter $w_{q}$ in the range of $-1/3<w_{q}<0$. Due to the presence of quintessence, Maxwell field damps more slowly. And when at $-1<w_{q}<-1/3$, it is similar to the black hole solution in the ds/Ads spacetime. The appropriate boundary conditions need to be modified.Comment: 6 pages, 3 figure

Mapping CHU9D Utility Scores from the PedsQL™ 4.0 SF-15

Background The Pediatric Quality of Life Inventory™ 4.0 Short Form 15 Generic Core Scales (hereafter the PedsQL) and the Child Health Utility-9 Dimensions (CHU9D) are two generic instruments designed to measure health-related quality of life in children and adolescents in the general population and paediatric patient groups living with specific health conditions. Although the PedsQL is widely used among paediatric patient populations, presently it is not possible to directly use the scores from the instrument to calculate quality-adjusted life-years (QALYs) for application in economic evaluation because it produces summary scores which are not preference-based. Objective This paper examines different econometric mapping techniques for estimating CHU9D utility scores from the PedsQL for the purpose of calculating QALYs for cost-utility analysis. Methods The PedsQL and the CHU9D were completed by a community sample of 755 Australian adolescents aged 15–17 years. Seven regression models were estimated: ordinary least squares estimator, generalised linear model, robust MM estimator, multivariate factorial polynomial estimator, beta-binomial estimator, finite mixture model and multinomial logistic model. The mean absolute error (MAE) and the mean squared error (MSE) were used to assess predictive ability of the models. Results The MM estimator with stepwise-selected PedsQL dimension scores as explanatory variables had the best predictive accuracy using MAE and the equivalent beta-binomial model had the best predictive accuracy using MSE. Conclusions Our mapping algorithm facilitates the estimation of health-state utilities for use within economic evaluations where only PedsQL data is available and is suitable for use in community-based adolescents aged 15–17 years. Applicability of the algorithm in younger populations should be assessed in further research

Multiscale nature of hysteretic phenomena: Application to CoPt-type magnets

We suggest a workable approach for the description of multiscale magnetization reversal phenomena in nanoscale magnets and apply it to CoPt-type alloys. We show that their hysteretic properties are governed by two effects originating at different length scales: a peculiar splitting of domain walls and their strong pinning at antiphase boundaries. We emphasize that such multiscale nature of hysteretic phenomena is a generic feature of nanoscale magnetic materials.Comment: 4 pages (revtex 4), 2 color EPS figure

Massive Charged Scalar Quasinormal Modes of Reissner-N\"ordstrom Black Hole Surrounded by Quintessence

We evaluate the complex frequencies of the normal modes for the massive charged scalar field perturbations around a Reissner-N\"ordstrom black hole surrounded by a static and spherically symmetric quintessence using third order WKB approximation approach. Due to the presence of quintessence, quasinormal frequencies damp more slowly. We studied the variation of quasinormal frequencies with charge of the black bole, mass and charge of perturbating scalar field and the quintessential state parameter.Comment: 9 pages, 9 figures and one tabl

Role of Gallium-67 scintigraphy in the evaluation of occult sepsis in the medical ICU

Patients in intensive care units (ICUs) frequently have multiple infections or persistent fever despite management. The aim of this study was to evaluate the diagnostic contribution of gallium-67 scintigraphy in ICU patients with suspected occult sepsis. One hundred and seventeen patients (> 18 years) who had undergone gallium-67 scintigraphy in the ICU of our medical center over a 3-year period were retrospectively reviewed and analyzed. Patients were categorized into Group 1 (n = 84), those with a known infectious source, but who still had persistent fever or sepsis despite antibiotic treatment or abscess drainage; or Group 2 (n = 33), those without an evident infectious source after clinical, physical, and imaging studies. Among the 117 patients, 19 (16.2%) had a new diagnosis. In Group 1, 12 patients (14%) had a new infection, including pneumonia (4 patients), bed sore infection (2 patients), pulmonary tuberculosis (2 patients), leg cellulitis (1 patient), psoas muscle abscess (1 patient), osteomyelitis (1 patient), and infective endocarditis (1 patient). In Group 2, seven patients (21.2%) had a new infectious source, including septic arthritis (3 patients), osteomyelitis (2 patients), neck abscess (1 patient), and cholecystitis (1 patient). Significant differences were not observed between patients with positive and negative findings on gallium-67 scintigraphy in characteristics, underlying diseases, laboratory data, and outcomes. Gallium-67 scintigraphy helped to detect new or additional infectious sites, particularly bone, joint, and soft tissues. However, differences in hospital stay and mortality were not observed between patients with positive and negative findings

Multiple full-length NS3 molecules are required for optimal unwinding of oligonucleotide DNA in vitro

NS3 (nonstructural protein 3) from the hepatitis C virus is a 3′ → 5′ helicase classified in helicase superfamily 2. The optimally active form of this helicase remains uncertain. We have used unwinding assays in the presence of a protein trap to investigate the first cycle of unwinding by full-length NS3. When the enzyme was in excess of the substrate, NS3 (500 nM) unwound &gt;80% of a DNA substrate containing a 15-nucleotide overhang and a 30-bp duplex (45:30-mer; 1 nM). This result indicated that the active form of NS3 that was bound to the DNA prior to initiation of the reaction was capable of processive DNA unwinding. Unwinding with varying ratios of NS3 to 45:30-mer allowed us to investigate the active form of NS3 during the first unwinding cycle. When the substrate concentration slightly exceeded that of the enzyme, little or no unwinding was observed, indicating that if a monomeric form of the protein is active, then it exhibits very low processivity. Binding of NS3 to the 45:30-mer was measured by electrophoretic mobility shift assays, resulting in KD = 2.7 ± 0.4 nM. Binding to individual regions of the substrate was investigated by measuring the KD for a 15-mer oligonucleotide as well as a 30-mer duplex. NS3 bound tightly to the 15-mer (KD = 1.3 ± 0.2 nM) and, surprisingly, fairly tightly to the double-stranded 30-mer (KD = 11.3 ± 1.3 nM). However, NS3 was not able to rapidly unwind a blunt-end duplex. Thus, under conditions of optimal unwinding, the 45:30-mer is initially saturated with the enzyme, including the duplex region. The unwinding data are discussed in terms of a model whereby multiple molecules of NS3 bound to the single-stranded DNA portion of the substrate are required for optimal unwinding

Quasi-normal modes of warped black holes and warped AdS/CFT correspondence

We analytically calculate the quasi-normal modes of various perturbations of spacelike stretched and null warped $AdS_3$ black holes. From AdS/CFT correspondence, these quasi-normal modes are expected to appear as the poles in momentum space of retarded Green functions of dual operators in CFT at finite temperature. We find that this is indeed the case, after taking into account of the subtle identification of quantum numbers. The subtlety comes from the fact that only after appropriate coordinate transformation the asymptotic geometries of warped black holes are the same as the ones of warped $AdS_3$ spacetimes. We show that in general the quasi-normal modes are in good agreement with the prediction of the warped AdS/CFT correspondence, up to a constant factor. As a byproduct, we compute the conformal dimensions of boundary operators dual to the perturbations. Our result gives strong support to the conjectured warped AdS/CFT correspondence.Comment: 26 pages; typos corrected, references added; more clarifications, match the version to appear in JHE

How to Run the Coupling in the Dipole Approach to the BFKL Equation

We use the dipole expansion to provide a systematic way of including the running coupling into the BFKL equation. In terms of a Borel representation, we obtain an expression for the kernel of the BFKL equation.Comment: 10 pages, latex, 1 figure, included. LaTeX2e compatibility problems fixed: no changes in content

Case Study: Verifying the Safety of an Autonomous Racing Car with a Neural Network Controller

This paper describes a verification case study on an autonomous racing car with a neural network (NN) controller. Although several verification approaches have been recently proposed, they have only been evaluated on low-dimensional systems or systems with constrained environments. To explore the limits of existing approaches, we present a challenging benchmark in which the NN takes raw LiDAR measurements as input and outputs steering for the car. We train a dozen NNs using reinforcement learning (RL) and show that the state of the art in verification can handle systems with around 40 LiDAR rays. Furthermore, we perform real experiments to investigate the benefits and limitations of verification with respect to the sim2real gap, i.e., the difference between a system’s modeled and real performance. We identify cases, similar to the modeled environment, in which verification is strongly correlated with safe behavior. Finally, we illustrate LiDAR fault patterns that can be used to develop robust and safe RL algorithms

Population Monte Carlo algorithms

We give a cross-disciplinary survey on ``population'' Monte Carlo algorithms. In these algorithms, a set of ``walkers'' or ``particles'' is used as a representation of a high-dimensional vector. The computation is carried out by a random walk and split/deletion of these objects. The algorithms are developed in various fields in physics and statistical sciences and called by lots of different terms -- ``quantum Monte Carlo'', ``transfer-matrix Monte Carlo'', ``Monte Carlo filter (particle filter)'',``sequential Monte Carlo'' and ``PERM'' etc. Here we discuss them in a coherent framework. We also touch on related algorithms -- genetic algorithms and annealed importance sampling.Comment: Title is changed (Population-based Monte Carlo -> Population Monte Carlo). A number of small but important corrections and additions. References are also added. Original Version is read at 2000 Workshop on Information-Based Induction Sciences (July 17-18, 2000, Syuzenji, Shizuoka, Japan). No figure