Linear transformations which map the classes of ω-matrices and τ-matrices into or onto themselves

AbstractA characterization is given for linear transformations on n × n matrices which map the classes of ω- and τ-matrices into themselves, under certain nonsingularity assumptions on the mapping. These results are also used in obtaining the characterization of those linear transformations which map the above classes onto themselves

Greece and the media – A qualitative assessment of the news impact on credit conditions in the Greek debt crisis

We study the extent to which events transmitted by the media affect Greek bond interest rates by analyzing qualitatively articles in global newspapers during the Greek debt crisis. We focus on dates with strong changes in the yield to maturity of Greek government bonds in order to test whether news coverage matters for financial markets. We relate our results to a quantitative measure of media coverage using the novel method of topic models and examine days with a high level of a quantitative topic series. News coverage seems to matter on the majority of dates. However, we also find dates without crucial events and media coverage but that have strong changes in the bond yield and that seem affected by sources other than the media. The quantitative news measure regularly reveals relevant news articles on the days we analyzed

Benzo[a]pyrene-induced DNA adducts and gene expression profiles in target and non-target organs for carcinogenesis in mice

Background: Gene expression changes induced by carcinogens may identify differences in molecular function between target and non-target organs. Target organs for benzo[a]pyrene (BaP) carcinogenicity in mice (lung, spleen and forestomach) and three non-target organs (liver, colon and glandular stomach) were investigated for DNA adducts by 32P-postlabelling, for gene expression changes by cDNA microarray and for miRNA expression changes by miRNA microarray after exposure of animals to BaP. Results: BaP-DNA adduct formation occurred in all six organs at levels that did not distinguish between target and non-target. cDNA microarray analysis showed a variety of genes modulated significantly by BaP in the six organs and the overall gene expression patterns were tissue specific. Gene ontology analysis also revealed that BaP-induced bioactivities were tissue specific; eight genes (Tubb5, Fos, Cdh1, Cyp1a1, Apc, Myc, Ctnnb1 and Cav) showed significant expression difference between three target and three non-target organs. Additionally, several gene expression changes, such as in Trp53 activation and Stat3 activity suggested some similarities in molecular mechanisms in two target organs (lung and spleen), which were not found in the other four organs. Changes in miRNA expression were generally tissue specific, involving, in total, 21/54 miRNAs significantly up- or down-regulated. Conclusions: Altogether, these findings showed that DNA adduct levels and early gene expression changes did not fully distinguish target from non-target organs. However, mechanisms related to early changes in p53, Stat3 and Wnt/β-catenin pathways may play roles in defining BaP organotropism

Reorganization of the auditory-perceptual space across the human vocal range

We analyzed the auditory-perceptual space across a substantial portion of the human vocal range (220-1046 Hz) using multidimensional scaling analysis of cochlea-scaled spectra from 250-ms vowel segments, initially studied in Friedrichs et al. (2017) J. Acoust. Soc. Am. 142 1025-1033. The dataset comprised the vowels /i y e {\o} {\epsilon} a o u/ (N=240) produced by three native German female speakers, encompassing a broad range of their respective voice frequency ranges. The initial study demonstrated that, during a closed-set identification task involving 21 listeners, the point vowels /i a u/ were significantly recognized at fundamental frequencies (fo) nearing 1 kHz, whereas the recognition of other vowels decreased at higher pitches. Building on these findings, our study revealed systematic spectral shifts associated with vowel height and frontness as fo increased, with a notable clustering around /i a u/ above 523 Hz. These observations underscore the pivotal role of spectral shape in vowel perception, illustrating the reliance on acoustic anchors at higher pitches. Furthermore, this study sheds light on the quantal nature of these vowels and their potential impact on language evolution, offering a plausible explanation for their widespread presence in the world's languages

Relevance-driven acquisition and rapid on-site analysis of 3d geospatial data

One central problem in geospatial applications using 3D models is the tradeoff between detail and acquisition cost during acquisition, as well as processing speed during use. Commonly used laser-scanning technology can be used to record spatial data in various levels of detail. Much detail, even on a small scale, requires the complete scan to be conducted at high resolution and leads to long acquisition time, as well as a great amount of data and complex processing. Therefore, we propose a new scheme for the generation of geospatial 3D models that is driven by relevance rather than data. As part of that scheme we present a novel acquisition and analysis workflow, as well as supporting data-models. The workflow includes on-site data evaluation (e.g. quality of the scan) and presentation (e.g. visualization of the quality), which demands fast data processing. Thus, we employ high performance graphics cards (GPGPU) to effectively process and analyze large volumes of LIDAR data. In particular we present a density calculation based on k-nearest-neighbor determination using OpenCL. The presented GPGPU-accelerated workflow enables a fast data acquisition with highly detailed relevant objects and minimal storage requirements.State of Lower-SaxonyVolkswagen Foundatio

Stochastic model for the 3D microstructure of pristine and cyclically aged cathodes in Li-ion batteries

It is well-known that the microstructure of electrodes in lithium-ion batteries strongly affects their performance. Vice versa, the microstructure can exhibit strong changes during the usage of the battery due to aging effects. For a better understanding of these effects, mathematical analysis and modeling has turned out to be of great help. In particular, stochastic 3D microstructure models have proven to be a powerful and very flexible tool to generate various kinds of particle-based structures. Recently, such models have been proposed for the microstructure of anodes in lithium-ion energy and power cells. In the present paper, we describe a stochastic modeling approach for the 3D microstructure of cathodes in a lithium-ion energy cell, which differs significantly from the one observed in anodes. The model for the cathode data enhances the ideas of the anode models, which have been developed so far. It is calibrated using 3D tomographic image data from pristine as well as two aged cathodes. A validation based on morphological image characteristics shows that the model is able to realistically describe both, the microstructure of pristine and aged cathodes. Thus, we conclude that the model is suitable to generate virtual, but realistic microstructures of lithium-ion cathodes