Demographic analysis of benign paroxysmal positional vertigo as a common public health problem

Background: Benign paroxysmal positional vertigo (BPPV) is the most common peripheral vestibular problem. However, demographic analysis is few. Aim: The aim of this study was to document the demographic data of patients with BPPV regarding distribution of gender, age, associated problems, most common form, symptom duration, severity of nystagmus and cure rate. Subjects and Methods: A total of 263 patients with video‑nystagmography confirmed BPPV were enrolled in this retrospective study (2009‑2013). The data were collected in Anadolu Medical Center. Distribution of gender, age and affected side were reviewed. Associated problems were noted. Patients were analyzed according to the canal involvement, age, duration of symptoms, duration of nystagmus and recurrence. Mean values and standard deviations were calculated. One‑way ANOVA test was used for the analysis of the data (Statistical Package for the Social Sciences 17.0 version, IBM, Chicago, III, USA). Statistical significance was set at P < 0.05. Results: Women were affected more frequently than men (1:1.5). Comparative analysis of average age between the two gender groups was not statistically significant (P = 0.84). BPPV was common at middle age group. The incidence of affected side was not significant (P = 0.74). Posterior canal‑BPPV (PC‑BPPV) was the most leading one (129/263; 49%) followed by lateral canal (LC)‑canalolithiasis (60/263; 22.8%), LC‑cupulolithiasis (38/263; 14.5%) and superior canal‑BPPV (9/263; 3.4%). 55.1% of patients were defined as idiopathic (145/263). Associated problems were migraine (31/263; 11.8%), trauma (19/263; 7.2%), inner ear disorders (18/263; 6.8%) and other systemic problems (50/263; 19.1%). 72.6% of patients had symptoms <2 months (191/263). 23,6% of patients had intensive nystagmus lasting more than a minute regardless of canal involvement (62/263). 33% of patients required two or more maneuvers for the relief of symptoms (87/263). Conclusion: Symptoms are prone to recur in those of traumatic origin, associated inner ear problems and systemic disorders. As the prognostic factors are illuminated, preventive measures will be more effective and more patients will be cured properly.Keywords: Benign paroxysmal positional vertigo, Nystagmus, Semicircular cana

Root asymptotics of spectral polynomials for the Lame operator

The study of polynomial solutions to the classical Lam\'e equation in its algebraic form, or equivalently, of double-periodic solutions of its Weierstrass form has a long history. Such solutions appear at integer values of the spectral parameter and their respective eigenvalues serve as the ends of bands in the boundary value problem for the corresponding Schr\"odinger equation with finite gap potential given by the Weierstrass $\wp$-function on the real line. In this paper we establish several natural (and equivalent) formulas in terms of hypergeometric and elliptic type integrals for the density of the appropriately scaled asymptotic distribution of these eigenvalues when the integer-valued spectral parameter tends to infinity. We also show that this density satisfies a Heun differential equation with four singularities.Comment: final version, to appear in Commun. Math. Phys.; 13 pages, 3 figures, LaTeX2

Penrose Limit and String Theories on Various Brane Backgrounds

We investigate the Penrose limit of various brane solutions including Dp-branes, NS5-branes, fundamental strings, (p,q) fivebranes and (p,q) strings. We obtain special null geodesics with the fixed radial coordinate (critical radius), along which the Penrose limit gives string theories with constant mass. We also study string theories with time-dependent mass, which arise from the Penrose limit of the brane backgrounds. We examine equations of motion of the strings in the asymptotic flat region and around the critical radius. In particular, for (p,q) fivebranes, we find that the string equations of motion in the directions with the B field are explicitly solved by the spheroidal wave functions.Comment: 41 pages, Latex, minor correction

Forest Carbon Sequestration under the U.S. Biofuel Energy Policies

This paper analyzes impacts of the U.S. biofuel energy policies on the carbon sequestration by forest products, which is expressed as Harvested Wood Products (HWP) Contribution under the United Nations Framework Convention on Climate Change. Estimation for HWP Contribution is based on tracking carbon stock stored in wood and paper products in use and in solid-waste disposal sites (SWDS) from domestic consumption, harvests, imports, and exports. For this analysis, we hypothesize four alternative scenarios using the existing and pending U.S. energy policies by requirements for the share of biofuel to total energy consumption, and solve partial equilibrium for the U.S. timber market by 2030 for each scenario. The U.S. Forest Products Module (USFPM), created by USDA Forest Service Lab, operating within the Global Forest Products Model (GFPM) is utilized for projecting productions, supplies, and trade quantities for the U.S. timber market equilibrium. Based on those timber market components, we estimate scenario-specific HWP Contributions under the Production, the Stock Change, and the Atmospheric Approach suggested by Intergovernmental Panel on Climate Change (IPCC) Guidelines for National Greenhouse Gas Inventories using WOODCARB II created by VTT Technical Research Centre of Finland and modified by USDA Forest Service Lab. Lastly, we compare estimated results across alternative scenarios. Results show that HWP Contributions for the baseline scenario in 2009 for all approaches are estimated higher than estimates reported by U.S. Environmental Protection Agency in 2011, (e.g., 22.64 Tg C/ year vs 14.80 Tg C/ year under the Production Approach), which is due to the economic recovery, especially in housing construction, assumed in USFPM/GFPM. Projected HWP Contribution estimates show that the Stock Change Approach, which used to provide the highest estimates before 2009, estimate HWP Contribution lowest after 2009 due to the declining annual net imports. Though fuel wood consumption is projected to be expanded as an alternative scenario requires higher wood fuel share to total energy consumption, the overall impacts on the expansion in other timber products are very modest across scenarios in USFPM/GFPM. Those negligible impacts lead to small differences of HWP Contribution estimates under all approaches across alternative scenarios. This is explained by the points that increasing logging residues are more crucial for expansion in fuel wood projections rather than the expansion of forest sector itself, and that the current HWP Contribution does not include carbon held in fuel wood products by its definition.Forest Products, Carbon Sequestration, Biofuel Policies, HWP Contribution, Resource /Energy Economics and Policy,

Extension of Nikiforov-Uvarov Method for the Solution of Heun Equation

We report an alternative method to solve second order differential equations which have at most four singular points. This method is developed by changing the degrees of the polynomials in the basic equation of Nikiforov-Uvarov (NU) method. This is called extended NU method for this paper. The eigenvalue solutions of Heun equation and confluent Heun equation are obtained via extended NU method. Some quantum mechanical problems such as Coulomb problem on a 3-sphere, two Coulombically repelling electrons on a sphere and hyperbolic double-well potential are investigated by this method

Transformations of Heun's equation and its integral relations

We find transformations of variables which preserve the form of the equation for the kernels of integral relations among solutions of the Heun equation. These transformations lead to new kernels for the Heun equation, given by single hypergeometric functions (Lambe-Ward-type kernels) and by products of two hypergeometric functions (Erd\'elyi-type). Such kernels, by a limiting process, also afford new kernels for the confluent Heun equation.Comment: This version was published in J. Phys. A: Math. Theor. 44 (2011) 07520

Solutions for certain classes of Riccati differential equation

We derive some analytic closed-form solutions for a class of Riccati equation y'(x)-\lambda_0(x)y(x)\pm y^2(x)=\pm s_0(x), where \lambda_0(x), s_0(x) are C^{\infty}-functions. We show that if \delta_n=\lambda_n s_{n-1}-\lambda_{n-1}s_n=0, where \lambda_{n}= \lambda_{n-1}^\prime+s_{n-1}+\lambda_0\lambda_{n-1} and s_{n}=s_{n-1}^\prime+s_0\lambda_{k-1}, n=1,2,..., then The Riccati equation has a solution given by y(x)=\mp s_{n-1}(x)/\lambda_{n-1}(x). Extension to the generalized Riccati equation y'(x)+P(x)y(x)+Q(x)y^2(x)=R(x) is also investigated.Comment: 10 page

Thermodynamic large fluctuations from uniformized dynamics

Large fluctuations have received considerable attention as they encode information on the fine-scale dynamics. Large deviation relations known as fluctuation theorems also capture crucial nonequilibrium thermodynamical properties. Here we report that, using the technique of uniformization, the thermodynamic large deviation functions of continuous-time Markov processes can be obtained from Markov chains evolving in discrete time. This formulation offers new theoretical and numerical approaches to explore large deviation properties. In particular, the time evolution of autonomous and non-autonomous processes can be expressed in terms of a single Poisson rate. In this way the uniformization procedure leads to a simple and efficient way to simulate stochastic trajectories that reproduce the exact fluxes statistics. We illustrate the formalism for the current fluctuations in a stochastic pump model

Some boundary effects in quantum field theory

We have constructed a quantum field theory in a finite box, with periodic boundary conditions, using the hypothesis that particles living in a finite box are created and/or annihilated by the creation and/or annihilation operators, respectively, of a quantum harmonic oscillator on a circle. An expression for the effective coupling constant is obtained showing explicitly its dependence on the dimension of the box.Comment: 12 pages, Late

Non-unitary Conformal Field Theory and Logarithmic Operators for Disordered Systems

We consider the supersymmetric approach to gaussian disordered systems like the random bond Ising model and Dirac model with random mass and random potential. These models appeared in particular in the study of the integer quantum Hall transition. The supersymmetric approach reveals an osp(2/2)_1 affine symmetry at the pure critical point. A similar symmetry should hold at other fixed points. We apply methods of conformal field theory to determine the conformal weights at all levels. These weights can generically be negative because of non-unitarity. Constraints such as locality allow us to quantize the level k and the conformal dimensions. This provides a class of (possibly disordered) critical points in two spatial dimensions. Solving the Knizhnik-Zamolodchikov equations we obtain a set of four-point functions which exhibit a logarithmic dependence. These functions are related to logarithmic operators. We show how all such features have a natural setting in the superalgebra approach as long as gaussian disorder is concerned.Comment: Latex, 20 pages, one figure. Version accepted for publication in Nuclear Physics B, minor correction