1,474 research outputs found

    Blended Learning in der Universität : Eine Fallstudie zur Vorbereitung und Durchführung

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    Die Professur für BWL und Wirtschaftsinformatik am Fachbereich Wirtschaftswissenschaften der Justus-Liebig-Universität Gießen ist für die Grundstudiumsvorlesung \u27Grundzüge der Wirtschaftsinformatik\u27 und das begleitende PC-Tutorium zur verantwortlich, das jedes Wintersemester (WS) angeboten wird. Die Lerninhalte des vorlesungsbegleitenden PC-Tutoriums sind neben dem Vorlesungsstoff für die Abschlußklausur am Ende des WS relevant. Im WS 04/05 wurden ca. 480 Studierende auf 22 Präsenztutoriengruppen verteilt – im WS 05/06 ist die gleiche Studierendenzahl zu verzeichnen. Im WS 04/05 fand das PC-Tutorium letztmals als reine Präsenzveranstaltung im PC-Pool des FB 02 statt, der mit seinen PC-Arbeitsplätzen die Teilnehmerzahl einer Tutoriumsgruppe auf 24 beschränkt. Für die 22 PC-Tutorien des WS 04/05 wurden elf studentische Hilfskräfte über 4 Monate (November bis Februar) als Präsenztutoren mit je zwei wöchentlichen Tutoriumssitzungen beschäftigt. Um diesen beträchtlichen Personalmittelaufwand deutlich zu reduzieren, wird das PC-Tutorium im WS 05/06 im Rahmen eines Blended-Learning-Konzeptes über ein Mixtum von Präsenzelementen und Web-Based-Trainings angeboten. Im vorliegenden Arbeitspapier wird dieses Konzept theoretisch fundiert, entwickelt und seine Umsetzung in die Praxis beschrieben

    Inference of the genetic network regulating lateral root initiation in Arabidopsis thaliana

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    Regulation of gene expression is crucial for organism growth, and it is one of the challenges in Systems Biology to reconstruct the underlying regulatory biological networks from transcriptomic data. The formation of lateral roots in Arabidopsis thaliana is stimulated by a cascade of regulators of which only the interactions of its initial elements have been identified. Using simulated gene expression data with known network topology, we compare the performance of inference algorithms, based on different approaches, for which ready-to-use software is available. We show that their performance improves with the network size and the inclusion of mutants. We then analyse two sets of genes, whose activity is likely to be relevant to lateral root initiation in Arabidopsis, by integrating sequence analysis with the intersection of the results of the best performing methods on time series and mutants to infer their regulatory network. The methods applied capture known interactions between genes that are candidate regulators at early stages of development. The network inferred from genes significantly expressed during lateral root formation exhibits distinct scale-free, small world and hierarchical properties and the nodes with a high out-degree may warrant further investigation

    Pilot, Rollout and Monte Carlo Tree Search Methods for Job Shop Scheduling

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    Greedy heuristics may be attuned by looking ahead for each possible choice, in an approach called the rollout or Pilot method. These methods may be seen as meta-heuristics that can enhance (any) heuristic solution, by repetitively modifying a master solution: similarly to what is done in game tree search, better choices are identified using lookahead, based on solutions obtained by repeatedly using a greedy heuristic. This paper first illustrates how the Pilot method improves upon some simple well known dispatch heuristics for the job-shop scheduling problem. The Pilot method is then shown to be a special case of the more recent Monte Carlo Tree Search (MCTS) methods: Unlike the Pilot method, MCTS methods use random completion of partial solutions to identify promising branches of the tree. The Pilot method and a simple version of MCTS, using the ε\varepsilon-greedy exploration paradigms, are then compared within the same framework, consisting of 300 scheduling problems of varying sizes with fixed-budget of rollouts. Results demonstrate that MCTS reaches better or same results as the Pilot methods in this context.Comment: Learning and Intelligent OptimizatioN (LION'6) 7219 (2012

    Root cortex development is fine-tuned by the interplay of MIGs, SCL3 and DELLAs during arbuscular mycorrhizal symbiosis

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    Root development is a crucial process that determines the ability of plants to acquire nutrients, adapt to the substrate and withstand changing environmental conditions. Root plasticity is controlled by a plethora of transcriptional regulators that allow, in contrast to tissue development in animals, post-embryonic changes that give rise to new tissue and specialized cells. One of these changes is the accommodation in the cortex of hyperbranched hyphae of symbiotic arbuscular mycorrhizal (AM) fungi, called arbuscules. Arbuscule-containing cells undergo massive reprogramming to coordinate developmental changes with transport processes. Here we describe a novel negative regulator of arbuscule development, MIG3. MIG3 induces and interacts with SCL3, both of which modulate the activity of the central regulator DELLA, restraining cortical cell growth. As in a tug-of-war, MIG3-SCL3 antagonizes the function of the complex MIG1-DELLA, which promotes the cell expansion required for arbuscule development, adjusting cell size during the dynamic processes of the arbuscule life cycle. Our results in the legume plant Medicago truncatula advance the knowledge of root development in dicot plants, showing the existence of additional regulatory elements not present in Arabidopsis that fine-tune the activity of conserved central modules

    ORCID for Wikidata. Data enrichment for scientometric applications

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    Due to its numerous bibliometric entries of scholarly articles and connected information Wikidata can serve as an open and rich source for deep scientometrical analyses. However, there are currently certain limitations: While 31.5% of all Wikidata entries represent scientific articles, only 8.9% are entries describing a person and the number of entries researcher is accordingly even lower. Another issue is the frequent absence of established relations between the scholarly article item and the author item although the author is already listed in Wikidata. To fill this gap and to improve the content of Wikidata in general, we established a workflow for matching authors and scholarly publications by integrating data from the ORCID (Open Researcher and Contributor ID) database. By this approach we were able to extend Wikidata by more than 12k author-publication relations and the method can be transferred to other enrichments based on ORCID data. This is extension is beneficial for Wikidata users performing bibliometrical analyses or using such metadata for other purposes

    Pseudomonas putida KT2440 is naturally endowed to withstand industrial-scale stress conditions

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    Pseudomonas putida is recognized as a very promising strain for industrial application due to its high redox capacity and frequently observed tolerance towards organic solvents. In this research, we studied the metabolic and transcriptional response of P. putida KT2440 exposed to large-scale heterogeneous mixing conditions in the form of repeated glucose shortage. Cellular responses were mimicked in an experimental setup comprising a stirred tank reactor and a connected plug flow reactor. We deciphered that a stringent response-like transcriptional regulation programme is frequently induced, which seems to be linked to the intracellular pool of 3-hydroxyalkanoates (3-HA) that are known to serve as precursors for polyhydroxyalkanoates (PHA). To be precise, P. putida is endowed with a survival strategy likely to access cellular PHA, amino acids and glycogen in few seconds under glucose starvation to obtain ATP from respiration, thereby replenishing the reduced ATP levels and the adenylate energy charge. Notably, cells only need 0.4% of glucose uptake to build those 3-HA-based energy buffers. Concomitantly, genes that are related to amino acid catabolism and β-oxidation are upregulated during the transient absence of glucose. Furthermore, we provide a detailed list of transcriptional short- and long-term responses that increase the cellular maintenance by about 17% under the industrial-like conditions tested.publishersversionpublishe

    Recurrent myelitis after allogeneic stem cell transplantation. Report of two cases

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    <p>Abstract</p> <p>Background</p> <p>Allogeneic and autologous haematopoietic stem cell transplantation are established treatment options for haematological malignancies and may possibly be employed to treat a range of genetic and autoimmune diseases.</p> <p>Case presentation</p> <p>We report two patients who developed an acute myelitis within their thoracic spinal cord after allogeneic stem cell transplantation. Myelitis in these patients was not related to graft versus host disease or immune reconstitution and was responsive to intravenous methylprednisolone and cyclophosphamide.</p> <p>Conclusions</p> <p>Myelitis is a possibly disabling consequence of haematopoietic stem cell transplantation.</p

    Discrete Particle Swarm Optimization for the minimum labelling Steiner tree problem

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    Particle Swarm Optimization is an evolutionary method inspired by the social behaviour of individuals inside swarms in nature. Solutions of the problem are modelled as members of the swarm which fly in the solution space. The evolution is obtained from the continuous movement of the particles that constitute the swarm submitted to the effect of the inertia and the attraction of the members who lead the swarm. This work focuses on a recent Discrete Particle Swarm Optimization for combinatorial optimization, called Jumping Particle Swarm Optimization. Its effectiveness is illustrated on the minimum labelling Steiner tree problem: given an undirected labelled connected graph, the aim is to find a spanning tree covering a given subset of nodes, whose edges have the smallest number of distinct labels
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