Comparison of two methods for determining a substance is a common procedure in clinical chemistry. Almost without exception, normal theory statistics are used with the tacit assumption that the data under test show gaussian distributions. Experience has led us to question this assumption for populations of differences between values obtained by two methods applied to common samples and for popu...

This paper will attempt to illustrate the use of a kaleidoscope metaphor as a template for the organization and analysis of qualitative research data. It will provide a brief overview of the constant comparison method, examining such processes as categorization, comparison, inductive analysis, and refinement of data bits and categories. Graphic representations of our metaphoric kaleidoscope wil...

Wound healing scratch assay is a frequently used method to characterize cell migration, which is an important biological process in the course of development, tissue repair, and immune response for example. The measurement of wound healing rate, however, varies among different studies. Here we summarized these measurements into three types: (I) direct rate average; (II) regression rate average;...

The class of quasiseparable matrices is defined by the property that any submatrix entirely below or above the main diagonal has small rank, namely below a bound called the order of quasiseparability. These matrices arise naturally in solving PDE’s for particle interaction with the Fast Multi-pole Method (FMM), or computing generalized eigenvalues. From these application fields, structured repr...

Reliability of the listening test design has a great influence on the performance of the quality estimation model. In this paper we compare four different listening test designs by Monte Carlo simulation. Three common problems of interval scale ratings are included in the simulation, and their influences on the performance of estimating the underlying true quality are investigated. It turns out...

The luminous high-redshift (z = 2.17) quasar S5 0836+710 has been observed in October 1997 with the VSOP at 1.6GHz and 5GHz. We report here a previously unpublished image made from the data at 1.6GHz and compare the structure of a relativistic jet in this quasazr at the two frequencies. We present a spectral index image tracing spectral properties of the jet up to ∼ 40 milliarcsecond distance f...

In this article, we analyze the evolution of prices in deregulated electricity markets. We present a general model that simultaneously takes into account the following features: seasonal patterns, price spikes, mean reversion, price dependent volatilities and long-term non-stationarity. We estimate the parameters of the model using historical data from the European Energy Exchange. Finally, it ...

This paper estimates a price elasticity using a flexible demand specification on survey data where prices are observed with error are correlated with household characteristics. The demand function is modeled as being a polynomial (and more generally also including trigonometric terms) in the unobserved true prices and the form of the dependency between the observed (mismeasured) prices and hous...

Minimization problems in l for Tikhonov functionals with sparsity constraints are considered. Sparsity of the solution is ensured by a weighted l penalty term. The necessary and sufficient condition for optimality is shown to be slantly differentiable (Newton differentiable), hence a semismooth Newton method is applicable. Local superlinear convergence of this method is proved. Numerical exampl...

Macroeconometric models with forward-looking variables give raise to very large systems of equations that requires heavy computations. These models was influenced by the development of new and efficient computational techniques and they are an interesting testing ground for the numerical methods addressed in this research. The most difficult problem in solving such models is to obtain the solut...