Efficient Maximum-Likelihood Decoding of Linear Block Codes on Binary Memoryless Channels

In this work, we consider efficient maximum-likelihood decoding of linear block codes for small-to-moderate block lengths. The presented approach is a branch-and-bound algorithm using the cutting-plane approach of Zhang and Siegel (IEEE Trans. Inf. Theory, 2012) for obtaining lower bounds. We have compared our proposed algorithm to the state-of-the-art commercial integer program solver CPLEX, and for all considered codes our approach is faster for both low and high signal-to-noise ratios. For instance, for the benchmark (155,64) Tanner code our algorithm is more than 11 times as fast as CPLEX for an SNR of 1.0 dB on the additive white Gaussian noise channel. By a small modification, our algorithm can be used to calculate the minimum distance, which we have again verified to be much faster than using the CPLEX solver.Comment: Submitted to 2014 International Symposium on Information Theory. 5 Pages. Accepte

Navigating through Discourses of Belonging: Letters of Complaint and Request during National Socialism

National Socialism, one could argue, was all about belonging: belonging to the ‘Volk’ or the ‘Volksgemeinschaft’, belonging to the ‘Aryan’ or ‘Non-Aryan race’, belonging to the National Socialist ‘movement’, and so on. These categories of belonging worked both inclusionary and exclusionary and they were constituted, proclaimed and enacted to a great part through language. What is more, they had to be performed through communicative acts. For the normative side of National Socialist propaganda and legislation, this seems rather obvious and one-directional. On the side of the general population, however, this entailed a mixture of communicative need to position oneself vis-à-vis National Socialism (mostly in affirmative ways), but also the urge to do so willingly. When we look at the language use of ‘ordinary people’ in different communicative situations and texts during National Socialism, we have to focus on these dimensions of discursive collusion, co-constitutionand appropriation. People during National Socialism, such is our hypothesis, navigated through discourses of belonging and by that made them real and effective. Besides diaries, war letters and autobiographical writings, one way to grasp this phenomenon is to analyse petitions, i.e., letters of complaint and request sent in large numbers by ‘ordinary people’ to public authorities of the party and the state. As I will show by some examples, letter-writers tried to inscribe themselves within (what they took for) National Socialist discourses of belonging in order to legitimate their claims. By doing so, they co-constituted and co-created the discursive realm of National Socialism

pH in the trans-Golgi network/early endosome of Arabidopsis thaliana: Suppliers and consumers

The trans-Golgi network (TGN)/ early endosome (EE) is the main sorting station for proteins travelling along the secretory- or endocytic route. Acidification by the TGN/EE-localised vacuolar-type proton (H+)-ATPase (V-ATPase) is essential for functional protein trafficking as well as compartment structure. Inhibition of this V-ATPase ceases protein trafficking through the TGN/EE and inhibits cell elongation. To sustain TGN/EE functions, luminal pH has to be kept on a homeostatic level. A mechanism to maintain V-ATPase-mediated acidification is to balance the bulk positive charges in the TGN/EE lumen accumulated by H+ pumping via parallel anion import. However, previous measurements of V-ATPase-dependent acidification in the TGN/EE were mainly done in transient expression systems and used sensors suited for rather alkaline pH conditions. Furthermore, TGN/EE-localised anion transporter from the ClC-family which have been proposed to serve in luminal charge balance are largely uncharacterised. For that purpose, in vivo TGN/EE pH measurements using the genetically encoded pH sensor pHusion linked to the TGN/EE resident protein SYP61 were established. We determined that the steady state pH of 5,6 in the TGN/EE in Arabidopsis roots is controlled by the combined activity of the V-ATPase and H+-coupled antiporters. Moreover the role of ClCd and ClCf in supporting the TGN/EElocalised V-ATPase in acidification was investigated. Whereas knock-out of both TGN/EElocalised ClCs caused male gametophyte lethality, we identified via inducible knock-downs an essential role of both transporters in cell elongation. However, neither TGN/EE pH nor TGN/EEmediated trafficking was altered upon reduced reduction of ClCf in the clcd background. Curiously, trans-Golgi pH was more acidic than WT due to a partial mislocalisation of the TGN/EE-localised V-ATPases to the Golgi stack. Finally, a computational modelling approach suggested that ClCd functions as Cl-/H+ antiporter whereas clear predictions on ClCf functions could not been made. We established a method to measure V-ATPase-mediated TGN/EE acidification in vivo in Arabidopsis thaliana. Furthermore, we showed that the TGN/EE is acidified by the V-ATPase and co-determined by TGN/EE-localised transporters. Besides VATPase activity, anion import in the TGN/EE mediated by two ClC members ClCd and ClCf is essential for cell elongation. By that we revealed a previously unknown role of luminal anion homeostasis in the TGN/EE

NHX-type Na+(K+)/H+ antiporters are required for TGN/EE trafficking and endosomal ion homeostasis in Arabidopsis thaliana

The regulation of ion and pH homeostasis of endomembrane organelles is critical for functional protein trafficking, sorting and modification in eukaryotic cells. pH homeostasis is maintained through the activity of vacuolar H+-ATPases (V-ATPases) pumping protons (H+) into the endomembrane lumen, and counter-action by cation/proton exchangers, such as the NHX family of Na+(K+)/H+ exchangers. In plants, V-ATPase activity at the trans-Golgi network/early endosome (TGN/EE) is important for secretory and endocytic trafficking; however, the role of the endosomal antiporters NHX5 and NHX6 in endomembrane trafficking is unclear. Here we show through genetic, pharmacological and live-cell imaging approaches that double knockout of NHX5 and NHX6 results in the impairment of endosome motility and protein recycling at the TGN/EE, but not in the secretion of integral membrane proteins. Furthermore, we report that nhx5 nhx6 mutants are partially insensitive to osmotic swelling of TGN/EE induced by the monovalent cation ionophore monensin, and to late endosomal swelling by the phosphatidylinositol 3/4-kinase inhibitor wortmannin, demonstrating that NHX5 and NHX6 function to regulate the luminal cation composition of endosomes

A System for Continuous Underground Site Mapping and Exploration

3D mapping becomes ever more important not only in industrial mobile robotic applications for AGV and production vehicles but also for search and rescue scenarios. In this chapter we report on our work of mapping and exploring underground mines. Our contribution is two-fold: First, we present our custom-built 3D laser range platform SWAP and compare it against an architectural laser scanner. The advantages are that the mapping vehicle can scan in a continuous mode and does not have to do stop-and-go scanning. The second contribution is the mapping tool mapit which supports and automates the registration of large sets of point clouds. The idea behind mapit is to keep the raw point cloud data as a basis for any map generation and only store all operations executed on the point clouds. This way the initial data do not get lost, and improvements on low-level date (e.g. improved transforms through loop closure) will automatically improve the final maps. Finally, we also present methods for visualization and interactive exploration of such maps

Cdx4 Dysregulates Hox Gene Expression and Generates Acute Myeloid Leukemia Alone and in Cooperation with Meis1a in a Murine Model

HOX genes have emerged as critical effectors of leukemogenesis, but the mechanisms that regulate their expression in leukemia are not well understood. Recent data suggest that the caudal homeobox transcription factors CDX1, CDX2, and CDX4, developmental regulators of HOX gene expression, may contribute to HOX gene dysregulation in leukemia. We report here that CDX4 is expressed normally in early hematopoietic progenitors and is expressed aberrantly in approximately 25% of acute myeloid leukemia (AML) patient samples. Cdx4 regulates Hox gene expression in the adult murine hematopoietic system and dysregulates Hox genes that are implicated in leukemogenesis. Furthermore, bone marrow progenitors that are retrovirally engineered to express Cdx4 serially replate in methylcellulose cultures, grow in liquid culture, and generate a partially penetrant, long-latency AML in bone marrow transplant recipients. Coexpression of the Hox cofactor Meis1a accelerates the Cdx4 AML phenotype and renders it fully penetrant. Structure-function analysis demonstrates that leukemic transformation requires intact Cdx4 transactivation and DNA-binding domains but not the putative Pbx cofactor interaction motif. Together, these data indicate that Cdx4 regulates Hox gene expression in adult hematopoiesis and may serve as an upstream regulator of Hox gene expression in the induction of acute leukemia. Inasmuch as many human leukemias show dysregulated expression of a spectrum of HOX family members, these collective findings also suggest a central role for CDX4 expression in the genesis of acute leukemia

Numerical simulation of dual-phase steel based on real and virtual three-dimensional microstructures

Dual-phase steel shows a strong connection between its microstructure and its mechanical properties. This structure–property correlation is caused by the composition of the microstructure of a soft ferritic matrix with embedded hard martensite areas, leading to a simultaneous increase in strength and ductility. As a result, dual-phase steels are widely used especially for strength-relevant and energy-absorbing sheet metal structures. However, their use as heavy plate steel is also desirable. Therefore, a better understanding of the structure–property correlation is of great interest. Microstructure-based simulation is essential for a realistic simulation of the mechanical properties of dual-phase steel. This paper describes the entire process route of such a simulation, from the extraction of the microstructure by 3D tomography and the determination of the properties of the individual phases by nanoindentation, to the implementation of a simulation model and its validation by experiments. In addition to simulations based on real microstructures, simulations based on virtual microstructures are also of great importance. Thus, a model for the generation of virtual microstructures is presented, allowing for the same statistical properties as real microstructures. With the help of these structures and the aforementioned simulation model, it is then possible to predict the mechanical properties of a dual-phase steel, whose three-dimensional (3D) microstructure is not yet known with high accuracy. This will enable future investigations of new dual-phase steel microstructures within a virtual laboratory even before their production