Wide-angle formulation of the Beilis-Tappert method.

The theory and numerical examples are given for a wide-angle formulation of the Beilis-Tappert method for wave propagation over irregular terrain. The vertical wave number k in the Beilis-Tappert method is not a physical wave number. Consequently, an essential but previously unknown element of the Beilis-Tappert method is the need to use a slope-dependent k-space vertical wave number filter.

Rapid visual field progression in a patient with glaucoma as the presenting manifestation of sarcoidosis.

Purpose: To report a case of accelerated visual field progression secondary to a new orbital apex lesion in a patient with a longstanding history of fatigue and cough.

Observations: A 73-year-old myopic female with known open angle glaucoma presented with accelerated unilateral visual field progression. Maximally tolerated medical therapy was instituted over a period of 1-2 years with imminent discussions of surgical intervention.

A Legendre-Galerkin spectral method for constructing atmospheric acoustic normal modes.

A Legendre-Galerkin spectral method is applied to the construction of atmospheric acoustic normal modes above level ground, represented by a complex impedance. A search in the complex plane for modal eigenvalues is replaced by a complex symmetric matrix eigenvalue problem. The Legendre-Galerkin spectral method projects the acoustic normal modes onto an orthogonal basis of Legendre polynomials.

Eigenfunction approach to the Green's function parabolic equation in outdoor sound: A tutorial.

Understanding the physics and mathematics underlying a computational algorithm such as the Green's function parabolic equation (GFPE) is both useful and worthwhile. To this end, the present article aims to give a more widely accessible derivation of the GFPE algorithm than was given originally by Gilbert and Di [(1993). J.

A numerically stable formulation of the Green's function parabolic equation: Subtracting the surface-wave pole.

The original formulation of the Green's function parabolic equation (GFPE) can have numerical accuracy problems for large normalized surface impedances. To solve the accuracy problem, an improved form of the GFPE has been developed. The improved GFPE formulation is similar to the original formulation, but it has the surface-wave pole "subtracted.

Predictors of intraoperative hypotension and bradycardia.

Background: Perioperative hypotension and bradycardia in the surgical patient are associated with adverse outcomes, including stroke. We developed and evaluated a new preoperative risk model in predicting intraoperative hypotension or bradycardia in patients undergoing elective noncardiac surgery.

Methods: Prospective data were collected in 193 patients undergoing elective, noncardiac surgery.

Children with severe early childhood caries: streptococci genetic strains within carious and white spot lesions.

Background And Objectives: Mutans streptococci (MS) are one of the major microbiological determinants of dental caries. The objectives of this study are to identify distinct MS and non-MS streptococci strains that are located at carious sites and non-carious enamel surfaces in children with severe early childhood caries (S-ECC), and assess if cariogenic MS and non-cariogenic streptococci might independently exist as primary bacterial strains on distinct sites within the dentition of individual children.

Design: Dental plaque from children (N=20; aged 3-6) with S-ECC was collected from carious lesions (CLs), white spot lesions (WSLs) and non-carious enamel surfaces.

Application of the Beilis-Tappert parabolic equation method to sound propagation over irregular terrain.

The Beilis-Tappert (1979) parabolic equation method is attractive for irregular terrain because it treats surface variations in terms of a simple multiplicative factor ("phase screen"). However, implementing the exact sloping-surface impedance condition is problematic if one wants the computational efficiency of a Fourier parabolic equation algorithm. This article investigates an approximate flat-ground impedance condition that allows the Beilis-Tappert phase screen method to be used with a Fourier algorithm without any added complications.

A generalized polar coordinate method for sound propagation over large-scale irregular terrain.

The polar coordinate method in You [Ph.D. thesis, The University of Mississippi (1993)] is rederived in differential form and is generalized by defining a local, continuously varying, radius of curvature.

A direct method for measuring acoustic ground impedance in long-range propagation experiments.

A method is reported for determining ground impedance in long-range propagation experiments by using the definition of impedance directly. The method is envisioned as way of measuring the impedence at multiple locations along the propagation path, using the signals broadcast during the experiment itself. In a short-range (10 m) test, the direct method was in good agreement with a more conventional model-based least-squares method.

Chaperone-targeting cytotoxin and endoplasmic reticulum stress-inducing drug synergize to kill cancer cells.

Diverse physiological and therapeutic insults that increase the amount of unfolded or misfolded proteins in the endoplasmic reticulum (ER) induce the unfolded protein response, an evolutionarily conserved protective mechanism that manages ER stress. Glucose-regulated protein 78/immunoglobulin heavy-chain binding protein (GRP78/BiP) is an ER-resident protein that plays a central role in the ER stress response and is the only known substrate of the proteolytic A subunit (SubA) of a novel bacterial AB(5) toxin. Here, we report that an engineered fusion protein, epidermal growth factor (EGF)-SubA, combining EGF and SubA, is highly toxic to growing and confluent epidermal growth factor receptor-expressing cancer cells, and its cytotoxicity is mediated by a remarkably rapid cleavage of GRP78/BiP.

Observation of low-frequency acoustic surface waves in the nocturnal boundary layer.

A natural terrain surface, because of its porosity, can support an acoustic surface wave that is a mechanical analog of the familiar vertically polarized surface wave in AM radio transmission. At frequencies of several hundred hertz, the acoustic surface wave is attenuated over distances of a few hundred meters. At lower frequencies (e.

A theoretical treatment of the long range propagation of impulsive signals under strongly ducted nocturnal conditions.

On clear nights, over flat land, a sound duct develops in which sound can carry to great distances. As is the case with all ducted propagation, there is strong dispersion so that a broadband signal undergoes severe distortion as it propagates. The signal received at long ranges from an impulsive source is a wave train, of much greater duration than the initial impulse, consisting of a series of arrivals.

An exact point source starting field for the Fourier parabolic equation in outdoor sound propagation.

A method for exactly representing a point source starting field in a Fourier parabolic equation calculation is presented. The formulation is based on an exact, analytic expression for the field in vertical wave number space (k space). The field in vertical coordinate space (z space) is obtained via a Fourier transform of the k-space field.

The near-ground structure of the nocturnal sound field.

The near-ground behavior of the low-frequency (100 Hz to 500 Hz) sound field in the nocturnal sound duct is studied theoretically and experimentally. In the first few meters of the atmosphere, narrow-band sound fields are found to have a characteristic vertical structure. The sound field is the superposition of a "surface mode," whose magnitude decreases monotonically with altitude, with a sum of "higher modes," each of whose magnitudes has a pronounced minimum a few meters from the ground at approximately the same height.