We present three cases of intracorneal pencil graphite particles following penetrating ocular injury. Slit lamp examination revealed pencil graphite particles in the corneal stroma in all cases. Although we did not remove the particles, no complications occurred during the follow-up period. We assumed that removal of the pencil graphite particles was unnecessary, and it was avoided to prevent t...

This paper is related to the spectral stability of traveling wave solutions of partial differential equations. In the first part of the paper we use the Gohberg-Rouche Theorem to prove equality of the algebraic multiplicity of an isolated eigenvalue of an abstract operator on a Hilbert space, and the algebraic multiplicity of the eigenvalue of the corresponding Birman-Schwinger type operator pe...

This paper presents models for graphite pencil, drawing paper, blenders, and kneaded eraser that produce realistic looking pencil marks, textures, and tones. Our models are based on an observation of how lead pencils interact with drawing paper, and on the absorptive and dispersive properties of blenders and erasers interacting with lead material deposited over drawing paper. The models conside...

We consider the distance from a (square or rectangular) matrix pencil to the nearest matrix pencil in 2-norm that has a set of specified eigenvalues. We derive a singular value optimization characterization for this problem and illustrate its usefulness for two applications. First, the characterization yields a singular value formula for determining the nearest pencil whose eigenvalues lie in a...

The Pencil Code is a highly modular physics-oriented simulation code that can be adapted to wide range of applications. It primarily designed solve partial differential equations (PDEs) compressible hydrodynamics and has lots add-ons ranging from astrophysical magnetohydrodynamics (MHD) meteorological cloud microphysics engineering applications in combustion. Nevertheless, the framework general...

In this paper we present a new diagonal balancing technique for regular matrix pencils λB − A, which aims at reducing the sensitivity of the corresponding generalized eigenvalues. It is inspired from the balancing technique of a square matrix A and has a comparable complexity. Upon convergence, the diagonally scaled pencil has row and column norms that are balanced in a precise sense. We also s...

The objective of this study was to determine whether variation in psychological adjustment to physically disfiguring conditions is related to organisation of the content of appearance-related information in the self-concept. A cross-sectional design was employed, using 70 participants with a range of appearance problems recruited from support groups and the NHS. A postal paper and pencil task w...

Inspired by recent reports concerning the utilisation of hand drawn pencil macroelectrodes (PDEs), we report the fabrication, characterisation (physicochemical and electrochemical) and implementation (electrochemical sensing) of various PDEs drawn upon a flexible polyester substrate. Electrochemical characterisation reveals that there are no quantifiable electrochemical responses upon utilising...

In this paper we propose a new recursive algorithm for computing the staircase form of a matrix pencil, and implicitly its Kronecker structure. The algorithm compares favorably to existing ones in terms of elegance, versatility, and complexity. In particular, the algorithm without any modiication yields the structural invari-ants associated with a generalized state{space system and its system p...

BACKGROUND Tissue microarray technology has provided a high throughput means of evaluating potential biomarkers in archival pathological specimens. This study was carried out in order to produce tissue microarray blocks using mechanical pencil tips without high cost. METHOD Conventional mechanical pencil tips (Rotring Tikky II Mechanical Pencil 1.0 mm) were used to cut out 1 mm wax cylinders ...