MATHEMATICAL TREATMENT OF DIFFUSION PROCESSES OF GASES AND FLUIDS IN POROUS MEDIA

The transport of fluids and gases in narrow pore systems is described by the transport equation and the material balance equation. Applying the three methods to our parabolic problem shows the advantage that the number of unknowns is dramatically decreased and the implementation of the algorithm on a PC is possible

Subdivision Shell Elements with Anisotropic Growth

A thin shell finite element approach based on Loop's subdivision surfaces is proposed, capable of dealing with large deformations and anisotropic growth. To this end, the Kirchhoff-Love theory of thin shells is derived and extended to allow for arbitrary in-plane growth. The simplicity and computational efficiency of the subdivision thin shell elements is outstanding, which is demonstrated on a few standard loading benchmarks. With this powerful tool at hand, we demonstrate the broad range of possible applications by numerical solution of several growth scenarios, ranging from the uniform growth of a sphere, to boundary instabilities induced by large anisotropic growth. Finally, it is shown that the problem of a slowly and uniformly growing sheet confined in a fixed hollow sphere is equivalent to the inverse process where a sheet of fixed size is slowly crumpled in a shrinking hollow sphere in the frictionless, quasi-static, elastic limit.Comment: 20 pages, 12 figures, 1 tabl

Advanced Wireless Digital Baseband Signal Processing Beyond 100 Gbit/s

International audienceThe continuing trend towards higher data rates in wireless communication systems will, in addition to a higher spectral efficiency and lowest signal processing latencies, lead to throughput requirements for the digital baseband signal processing beyond 100 Gbit/s, which is at least one order of magnitude higher than the tens of Gbit/s targeted in the 5G standardization. At the same time, advances in silicon technology due to shrinking feature sizes and increased performance parameters alone won't provide the necessary gain, especially in energy efficiency for wireless transceivers, which have tightly constrained power and energy budgets. In this paper, we highlight the challenges for wireless digital baseband signal processing beyond 100 Gbit/s and the limitations of today's architectures. Our focus lies on the channel decoding and MIMO detection, which are major sources of complexity in digital baseband signal processing. We discuss techniques on algorithmic and architectural level, which aim to close this gap. For the first time we show Turbo-Code decoding techniques towards 100 Gbit/s and a complete MIMO receiver beyond 100 Gbit/s in 28 nm technology

Editorial

Magnetic resonance imaging (MRI) at ultra-high magnetic field strengths offers an increased signal-to-noise ratio (SNR) and has the potential to boost the MR image resolution. Cardiovascular applications remain challenging, as high-resolution image acquisitions are still too slow to capture a fast moving organ like the heart. Synchronisation of the acquisition to the heart motion is necessary to acquire an image over several consecutive heartbeats. The current gold-standard method for cardiac synchronisation is the electrocardiogram (ECG), which measures the electrical activity of the heart. Magnetohydrodynamic effects of the blood flow interfere with the ECG measurement and can affect reliable gating, which is particularly significant at higher magnetic field strengths. The work of this thesis presents new motion estimation methods that are based on radiofrequency (RF) scattering of a parallel-transmit coil and directly assess the heart motion, independent of the electrical activity of the heart. A cardiac motion signal is derived with a high SNR and with a number of potential gating features, which have a high accuracy when compared to ECG gating. No additional motion-monitoring hardware is needed other than the commercially available pTx system. Different RF pulse designs are proposed to integrate the scattering measurements into the normal MR image acquisition to estimate cardiac and respiratory motion in real-time on the MRI scanner. The integrated cardiac-respiratory motion framework is combined with a new MR imaging acquisition strategy to acquire high-resolution, 3D images of the heart during free breathing.</p

Microarray-based approach identifies microRNAs and their target functional patterns in polycystic kidney disease

Background: MicroRNAs (miRNAs) play key roles in mammalian gene expression and several cellular processes, including differentiation, development, apoptosis and cancer pathomechanisms. Recently the biological importance of primary cilia has been recognized in a number of human genetic diseases. Numerous disorders are related to cilia dysfunction, including polycystic kidney disease (PKD). Although involvement of certain genes and transcriptional networks in PKD development has been shown, not much is known how they are regulated molecularly. Results: Given the emerging role of miRNAs in gene expression, we explored the possibilities of miRNA-based regulations in PKD. Here, we analyzed the simultaneous expression changes of miRNAs and mRNAs by microarrays. 935 genes, classified into 24 functional categories, were differentially regulated between PKD and control animals. In parallel, 30 miRNAs were differentially regulated in PKD rats: our results suggest that several miRNAs might be involved in regulating genetic switches in PKD. Furthermore, we describe some newly detected miRNAs, miR-31 and miR-217, in the kidney which have not been reported previously. We determine functionally related gene sets, or pathways to reveal the functional correlation between differentially expressed mRNAs and miRNAs. Conclusion: We find that the functional patterns of predicted miRNA targets and differentially expressed mRNAs are similar. Our results suggest an important role of miRNAs in specific pathways underlying PKD

Zur Qualität von Kindertexten. Entwicklung eines Bewertungsinstruments in der Grundschule

Im Rahmen des Forschungsprojekts "Kooperative Schülerrückmeldungen bei der Textüberarbeitung im Deutschunterricht der Grundschule" wurde ein Ratingsystem entwickelt, mit dessen Hilfe die Qualität von Schülertexten in 10 Dimensionen eingeschätzt wurde. Die herangezogene Stichprobe bestand aus 132 Texten von Schülern des 3. Schuljahres. Die Analysen zeigen in einem ersten Schritt, dass sich die Qualität der Texte auf den 10 unterschiedlichen Dimensionen mit einer hohen Beurteilerübereinstimmung einschätzen ließ. Mittels konfirmatorischer Faktorenanalyse wurde in einem zweiten Schritt die angenommene Modellstruktur überprüft. Die entsprechenden Ergebnisse zeigen, dass das ursprünglich angenommene Modell nicht zu den Daten passte. Daher wurde das Modell modifiziert, indem drei Items aus dem Modell entfernt wurden. Die erneute Überprüfung des reduzierten Modells mit den beiden Faktoren Textualität konventionell und Textualität unkonventionell ergab schließlich einen akzeptablen Modellfit. Der Faktor Textualität konventionell setzt sich aus den Items Kohärenz, Implizitheit und Explizitheit des Textes sowie Wortschatz zusammen aus, der Faktor Textualität unkonventionell aus den Items sprachliches Wagnis und inhaltliches Wagnis zusammen. (DIPF/Orig.)In the project “Peer feedback within cooperative settings for text revision in German classes in primary schools” a rating system comprising 10 dimensions was developed to evaluate the quality of student story writing. The sample consisted of 132 texts written by 3rd grade students. First analyses show that the quality of student texts could be evaluated with an acceptable degree of correspondence among the raters. Secondly, the structure of the hypothesized model was tested by using a confirmatory factor analysis (CFA). These results indicated that the hypothesized model did not fit the data. Therefore the model was modified by eliminating three items. This modified model allows us to generate two valid factors (textuality – conventional/unconventional), which fit the model adequately. The factor textuality conventional comprises the items text coherency, textual implicitness, textual explicitness, vocabulary, the factor textuality unconventional comprises textual risk-taking, with regard to language and to content