315 research outputs found

    Memetic Graph Clustering

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    It is common knowledge that there is no single best strategy for graph clustering, which justifies a plethora of existing approaches. In this paper, we present a general memetic algorithm, VieClus, to tackle the graph clustering problem. This algorithm can be adapted to optimize different objective functions. A key component of our contribution are natural recombine operators that employ ensemble clusterings as well as multi-level techniques. Lastly, we combine these techniques with a scalable communication protocol, producing a system that is able to compute high-quality solutions in a short amount of time. We instantiate our scheme with local search for modularity and show that our algorithm successfully improves or reproduces all entries of the 10th DIMACS implementation challenge under consideration using a small amount of time

    Impact of light on Hypocrea jecorina and the multiple cellular roles of ENVOY in this process

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    <p>Abstract</p> <p>Background</p> <p>In fungi, light is primarily known to influence general morphogenesis and both sexual and asexual sporulation. In order to expand the knowledge on the effect of light in fungi and to determine the role of the light regulatory protein ENVOY in the implementation of this effect, we performed a global screen for genes, which are specifically effected by light in the fungus <it>Hypocrea jecorina </it>(anamorph <it>Trichoderma reesei</it>) using Rapid Subtraction Hybridization (RaSH). Based on these data, we analyzed whether these genes are influenced by ENVOY and if overexpression of ENVOY in darkness would be sufficient to execute its function.</p> <p>Results</p> <p>The cellular functions of the detected light responsive genes comprised a variety of roles in transcription, translation, signal transduction, metabolism, and transport. Their response to light with respect to the involvement of ENVOY could be classified as follows: (i) ENVOY-mediated upregulation by light; (ii) ENVOY-independent upregulation by light; (iii) ENVOY-antagonized upregulation by light; ENVOY-dependent repression by light; (iv) ENVOY-independent repression by light; and (v) both positive and negative regulation by ENVOY of genes not responsive to light in the wild-type. ENVOY was found to be crucial for normal growth in light on various carbon sources and is not able to execute its regulatory function if overexpressed in the darkness.</p> <p>Conclusion</p> <p>The different responses indicate that light impacts fungi like <it>H. jecorina </it>at several cellular processes, and that it has both positive and negative effects. The data also emphasize that ENVOY has an apparently more widespread cellular role in this process than only in modulating the response to light.</p

    Light-dependent roles of the G-protein α subunit GNA1 of Hypocrea jecorina (anamorph Trichoderma reesei)

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    <p>Abstract</p> <p>Background</p> <p>The filamentous ascomycete <it>Hypocrea jecorina </it>(anamorph <it>Trichoderma reesei</it>) is primarily known for its efficient enzymatic machinery that it utilizes to decompose cellulosic substrates. Nevertheless, the nature and transmission of the signals initiating and modulating this machinery are largely unknown. Heterotrimeric G-protein signaling represents one of the best studied signal transduction pathways in fungi.</p> <p>Results</p> <p>Analysis of the regulatory targets of the G-protein α subunit GNA1 in <it>H. jecorina </it>revealed a carbon source and light-dependent role in signal transduction. Deletion of <it>gna1 </it>led to significantly decreased biomass formation in darkness in submersed culture but had only minor effects on morphology and hyphal apical extension rates on solid medium. Cellulase gene transcription was abolished in Δ<it>gna1 </it>on cellulose in light and enhanced in darkness. However, analysis of strains expressing a constitutively activated GNA1 revealed that GNA1 does not transmit the essential inducing signal. Instead, it relates a modulating signal with light-dependent significance, since induction still required the presence of an inducer. We show that regulation of transcription and activity of GNA1 involves a carbon source-dependent feedback cycle. Additionally we found a function of GNA1 in hydrophobin regulation as well as effects on conidiation and tolerance of osmotic and oxidative stress.</p> <p>Conclusion</p> <p>We conclude that GNA1 transmits a signal the physiological relevance of which is dependent on both the carbon source as well as the light status. The widespread consequences of mutations in GNA1 indicate a broad function of this Gα subunit in appropriation of intracellular resources to environmental (especially nutritional) conditions.</p

    Pillnitzer Obstsorten & Obstunterlagen

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    Die Broschüre Pillnitzer Obstsorten ist seit ihrem erstmaligen Erscheinen im Jahre 1997 bei Fachleuten und Hobbygärtnern zu einem beliebten Informationsmaterial geworden. Die nach wie vor große Nachfrage im In- und Ausland und die Entwicklung neuer Sorten waren Anlass, die Broschüre erneut zu überarbeiten und auf einen aktuellen Stand zu bringen. Die Broschüre richtet sich an Fachleute für Obstbau, Obstbauern und Hobbygärtner. Redaktionsschluss: 01.12.201

    Learning defects from aircraft NDT data

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    Non-destructive evaluation of aircraft production is optimised and digitalised with Industry 4.0. The aircraft structures produced using fibre metal laminate are traditionally inspected using water-coupled ultrasound scans and manually evaluated. This article proposes Machine Learning models to examine the defects in ultrasonic scans of A380 aircraft components. The proposed approach includes embedded image feature extraction methods and classifiers to learn defects in the scan images. The proposed algorithm is evaluated by benchmarking embedded classifiers and further promoted to research with an industry-based certification process. The HoG-Linear SVM classifier has outperformed SURF-Decision Fine Tree in detecting potential defects. The certification process uses the Probability of Detection function, substantiating that the HoG-Linear SVM classifier detects minor defects. The experimental trials prove that the proposed method will be helpful to examiners in the quality control and assurance of aircraft production, thus leading to significant contributions to non-destructive evaluation 4.0

    A versatile toolkit for high throughput functional genomics with Trichoderma reesei

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    <p>Abstract</p> <p>Background</p> <p>The ascomycete fungus, <it>Trichoderma reesei </it>(anamorph of <it>Hypocrea jecorina</it>), represents a biotechnological workhorse and is currently one of the most proficient cellulase producers. While strain improvement was traditionally accomplished by random mutagenesis, a detailed understanding of cellulase regulation can only be gained using recombinant technologies.</p> <p>Results</p> <p>Aiming at high efficiency and high throughput methods, we present here a construction kit for gene knock out in <it>T. reesei</it>. We provide a primer database for gene deletion using the <it>pyr4, amdS </it>and <it>hph </it>selection markers. For high throughput generation of gene knock outs, we constructed vectors using yeast mediated recombination and then transformed a <it>T. reesei </it>strain deficient in non-homologous end joining (NHEJ) by spore electroporation. This NHEJ-defect was subsequently removed by crossing of mutants with a sexually competent strain derived from the parental strain, QM9414.</p> <p>Conclusions</p> <p>Using this strategy and the materials provided, high throughput gene deletion in <it>T. reesei </it>becomes feasible. Moreover, with the application of sexual development, the NHEJ-defect can be removed efficiently and without the need for additional selection markers. The same advantages apply for the construction of multiple mutants by crossing of strains with different gene deletions, which is now possible with considerably less hands-on time and minimal screening effort compared to a transformation approach. Consequently this toolkit can considerably boost research towards efficient exploitation of the resources of <it>T. reesei </it>for cellulase expression and hence second generation biofuel production.</p

    Inline Quality Control for Thermoplastic Automated Fibre Placement

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    Aerospace production is relying heavily on quality assurance, especially for lightweight materials such as carbon fiber reinforced plastics (CFRPs). Due to the sequential organization of manufacturing and quality assurance lead times for parts and machine downtime are increased. An example is the highly automated process of thermoset tape laying, where every ply is manually inspected. Customized solutions to integrate quality assurance do exist, however mainly for specific processes and hardware. This leads to costly, isolated and non-transferable systems. At the Center of Lightweight Production Technology in Augsburg, Germany a more versatile and modular concept for inline data acquisition, storage and evaluation is investigated. On the basis of a laser line and camera system a generic inline measurement system for automated fiber placement (AFP) is developed, that is capable to inspect a variety of quality aspects such as positional tolerances and material properties. In a database driven approach the collected data is stored and analyzed. This paper presents the generic inline measurement system, the data storage system and the obtained measurement results for a thermoplastic AFP process. Additionally suggestions for future improvements and possible applications are described

    Inline Quality Control for Thermoplastic Automated Fibre Placement

    Get PDF
    Aerospace production is relying heavily on quality assurance, especially for lightweight materials such as carbon fiber reinforced plastics (CFRPs). Due to the sequential organization of manufacturing and quality assurance lead times for parts and machine downtime are increased. An example is the highly automated process of thermoset tape laying, where every ply is manually inspected. Customized solutions to integrate quality assurance do exist, however mainly for specific processes and hardware. This leads to costly, isolated and non-transferable systems. At the Center of Lightweight Production Technology in Augsburg, Germany a more versatile and modular concept for inline data acquisition, storage and evaluation is investigated. On the basis of a laser line and camera system a generic inline measurement system for automated fiber placement (AFP) is developed, that is capable to inspect a variety of quality aspects such as positional tolerances and material properties. In a database driven approach the collected data is stored and analyzed. This paper presents the generic inline measurement system, the data storage system and the obtained measurement results for a thermoplastic AFP process. Additionally suggestions for future improvements and possible applications are described

    Metabolic engineering strategies for the improvement of cellulase production by Hypocrea jecorina

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    Hypocrea jecorina (= Trichoderma reesei) is the main industrial source of cellulases and hemicellulases used to depolymerise plant biomass to simple sugars that are converted to chemical intermediates and biofuels, such as ethanol. Cellulases are formed adaptively, and several positive (XYR1, ACE2, HAP2/3/5) and negative (ACE1, CRE1) components involved in this regulation are now known. In addition, its complete genome sequence has been recently published, thus making the organism susceptible to targeted improvement by metabolic engineering. In this review, we summarise current knowledge about how cellulase biosynthesis is regulated, and outline recent approaches and suitable strategies for facilitating the targeted improvement of cellulase production by genetic engineering

    Regulation of Meristem Morphogenesis by Cell Wall Synthases in Arabidopsis.

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    The cell walls of the shoot apical meristem (SAM), containing the stem cell niche that gives rise to the above-ground tissues, are crucially involved in regulating differentiation. It is currently unknown how these walls are built and refined or their role, if any, in influencing meristem developmental dynamics. We have combined polysaccharide linkage analysis, immuno-labeling, and transcriptome profiling of the SAM to provide a spatiotemporal plan of the walls of this dynamic structure. We find that meristematic cells express only a core subset of 152 genes encoding cell wall glycosyltransferases (GTs). Systemic localization of all these GT mRNAs by in situ hybridization reveals members with either enrichment in or specificity to apical subdomains such as emerging flower primordia, and a large class with high expression in dividing cells. The highly localized and coordinated expression of GTs in the SAM suggests distinct wall properties of meristematic cells and specific differences between newly forming walls and their mature descendants. Functional analysis demonstrates that a subset of CSLD genes is essential for proper meristem maintenance, confirming the key role of walls in developmental pathways.V.C. is in receipt of a Thailand Research Fund (TRF) grant for New Researcher (Grant Number TRG5880067), and a Research Supplement grant from Faculty of Science, Mahidol University. CB, MSD and AB acknowledge the support of the ARC Centre of Excellence in Plant Cell Walls, Australia (Grant Number CE110001007). EMM acknowledges support from the Gatsby Charitable Trust through Fellowships GAT3272/C and GAT3273-PR1, the Howard Hughes Medical Institute, the Gordon and Betty Moore Foundation (through Grant GBMF3406) and the US Department of Energy (through award DE-FG02-99ER13873). AP acknowledges support of the EU Marie-Curie FP7 COFUND People Programme through the award of an AgreenSkills grant no. 267196. RW acknowledges support from the Leverhulme Trust (Grant RPG-2015-285).This is the author accepted manuscript. The final version is available from Cell Press via http://dx.doi.org/10.1016/j.cub.2016.04.02
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