Über die Löslichkeit des Phosphors in Eisen und Eisen-Kohlenstoff-Legierungen unterhalb 1000°C

Schrifttumsübersicht über die Löslichkeit des Phosphors in Eisen. Eigene Untersuchung der Phosphorlöslichkeit mit Hilfe von Diffusionspaaren Fe₃P/Reineisen und Fe₃P[kohlenstoffhaltiges Eisen mit bis zu rd. 0,6% C. Untersuchung der Phosphorverteilung mit der Mikrosonde und Messung der Mikrohärte nach Diffusionsglühungen bei Temperaturen zwischen 600 und 910°C. Erörterung der Versuchsergebnisse.     

Reconstruction of volume data with quadratic super splines

We propose a new approach to reconstruct nondiscrete models from gridded volume samples. As a model, we use quadratic trivariate super splines on a uniform tetrahedral partition. We discuss the smoothness and approximation properties of our model and compare to alternative piecewise polynomial constructions. We observe, as a nonstandard phenomenon, that the derivatives of our splines yield optimal approximation order for smooth data, while the theoretical error of the values is nearly optimal due to the averaging rules. Our approach enables efficient reconstruction and visualization of the data. As the piecewise polynomials are of the lowest possible total degree two, we can efficiently determine exact ray intersections with an isosurface for ray-casting. Moreover, the optimal approximation properties of the derivatives allow us to simply sample the necessary gradients directly from the polynomial pieces of the splines. Our results confirm the efficiency of the quasi-interpolating method and demonstrate high visual quality for rendered isosurfaces.     

KlROM2 encodes an essential GEF homologue in Kluyveromyces lactis

Cellular integrity in yeasts is ensured by a rigid cell wall whose synthesis is controlled by a MAP kinase signal transduction cascade. In Saccharomyces cerevisiae upstream regulatory components of this MAP kinase pathway involve a single protein kinase C, which is regulated in part by interaction with the small GTPase Rho1p. This small G protein is in turn rendered inactive (GDP-bound) or is activated (GTP-bound) by the influence of GTPase activating proteins (GAPs) and the GDP/GTP exchange factors (GEFs), respectively. We report here on the isolation of a gene from Kluyveromyces lactis, KlROM2, which encodes a member of the latter protein family. The nucleotide sequence contains an open reading frame of 1227 amino acids, with an overall identity of 57% to the Rom2 protein of S. cerevisiae. Four conserved sequence motifs could be identified: a RhoGEF domain, a DEP sequence, a CNH domain and a less conserved pleckstrin homology (PH) sequence. Klrom2 null mutants show a lethal phenotype, which indicates that the gene may encode the only functional GEF regulating the cellular integrity pathway in K. lactis. Conditional genomic expression of KlROM2 resulted in sensitivity towards caffeine and Calcofluor white as typical phenotypes of mutants defective in this pathway. Overexpression of KIROM2 from multicopy plasmids under the control of the ScGAL1 promoter severely impaired growth in both S. cerevisiae and in K. lactis. The fact that the lethal phenotype was not prevented in mpk1 deletion mutants indicates that growth inhibition is not simply caused by hyperactivation of the Pkc1p signal transduction pathway.     

Future trends in data mining

Over recent years data mining has been establishing itself as one of the major disciplines in computer science with growing industrial impact. Undoubtedly, research in data mining will continue and even increase over coming decades. In this article, we sketch our vision of the future of data mining. Starting from the classic definition of “data mining”, we elaborate on topics that — in our opinion — will set trends in data mining.     

Contrast Restoration by Adaptive Countershading

The ABSTRACT is to be in fully-justified italicized text, between two horizontal lines, in one-column format, below the author and affiliation information. Use the word “Abstract” as the title, in 9-point Times, boldface type, left-aligned to the text, initially capitalized. The abstract is to be in 9-point, single-spaced type. The abstract may be up to 3 inches (7.62 cm) long. Leave one blank line after the abstract, then add the subject categories according to the ACM Classification Index (see http://www.acm.org/class/1998/ ).     

Moving Averages of Random Vectors with Regularly Varying Tails

Regular variation is an analytic condition on the tails of a probability distribution which is necessary for an extended central limit theorem to hold, when the tails are too heavy to allow attraction to a normal limit. The limiting distributions which can occur are called operator stable. In this paper we show that moving averages of random vectors with regularly varying tails are in the generalized domain of attraction of an operator stable law. We also prove that the sample autocovariance matrix of these moving averages is in the generalized domain of attraction of an operator stable law on the vector space of symmetric matrices.
AMS 1990 subject classification. Primary 62M10, secondary 62E20, 62F12, 60F05.     

Crystal Structure and Related Properties of Manganese-Doped Barium Titanate Ceramics

The influence of manganese on the crystallographic phase and the microstructure of BaTi_{1− x} Mn _x O₃ ceramics (0 ≤ x ≤ 0.05) is investigated. The crystal structure at room temperature changes from tetragonal to hexagonal between x = 0.005 and 0.017, which causes a drastic change in the microstructure. The Jahn_Teller distortion caused by the Mn_Ti³⁺ ions is proposed as the driving force for the phase transition. Annealing of the as-fired samples in both a reducing and oxidizing atmosphere restores the tetragonal phase, which is accompanied by a change in the microstructure based on the percentage of tetragonal phase.     

Control Points for Multivariate B-Spline Surfaces over Arbitrary Triangulations

This paper describes first results of a test implementation that implements the new multivariate B-splines as recently developed by Dahmen et al. 10for quadratics and cubics. The surface scheme is based on blending functions and control points and allows the modelling of   C ^{k − 1}  -continuous piecewise polynomial surfaces of degree k over arbitrary triangulations of the parameter plane. The surface scheme exhibits both affine invariance and the convex hull property, and the control points can be used to manipulate the shape of the surface locally. Additional degrees of freedom in the underlying knot net allow for the modelling of discontinuities. Explicit formulas are given for the representation of polynomials and piecewise polynomials as linear combinations of B-splines.