958 resultados para MASSIVE NUCLEI


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A 49-year-old male patient presented with a paravalvular leakage 18 years after aortic valve replacement. The patient received a mechanical valve and was weaned uneventfully from cardiopulmonary bypass. After a drop in the pressure curve of the left radial artery an additional line was placed in the proximal ascending aorta showing normal systemic pressure. Transesophageal echocardiography showed a massive circular thrombosis of the distal aortic arch. The patient received a covered stent to expand the residual aortic lumen and left the hospital in good health.

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Open collaborative projects are moving to the foreground of knowledge production. Some online user communities develop into longterm projects that generate a highly valuable and at the same time freely accessible output. Traditional copyright law that is organized around the idea of a single creative entity is not well equipped to accommodate the needs of these forms of collaboration. In order to enable a peculiar network-type of interaction participants instead draw on public licensing models that determine the freedoms to use individual contributions. With the help of these access rules the operational logic of the project can be implemented successfully. However, as the case of the Wikipedia GFDL-CC license transition demonstrates, the adaptation of access rules in networks to new circumstances raises collective action problems and suffers from pitfalls caused by the fact that public licensing is grounded in individual copyright. Legal governance of open collaboration projects is a largely unexplored field. The article argues that the license steward of a public license assumes the position of a fiduciary of the knowledge commons generated under the license regime. Ultimately, the governance of decentralized networks translates into a composite of organizational and contractual elements. It is concluded that the production of global knowledge commons relies on rules of transnational private law.

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Massive Open Online Courses (MOOCs) bezeichnen Kurse, die online stattfinden und auf Grund fehlender Zugangsbeschränkungen und kostenfreien Zugangs sehr hohe Teilnehmerzahlen erreichen. Der erste MOOC wurde 2011 durch Sebastian Thrun, Professor für Informatik an der Stanford University, zum Thema der Künstlichen Intelligenz angeboten und hatte 160.000 Teilnehmende. In der Folge wurden MOOCs als die revolutionäre Lehr-/Lerninnovation gepriesen, immer mehr Unternehmen gründeten MOOCs-Plattformen. Seit Ende 2012 bieten auch in Deutschland erste Institutionen eigene Plattformen mit MOOCs an. Man unterscheidet im Wesentlichen zwei Varianten – xMoocs und cMOOCs: xMoocs bieten auf Video aufgezeichnete Vorlesungen, die durch Tests und Fragen unterbrochen und zu denen Aufgaben ausgeteilt werden. Sie werden ergänzt durch Foren. cMOOCs orientieren sich eher an der Form eines Seminars oder Workshops, in ihnen können die Teilnehmenden die Inhalte selbst miterarbeiten und -gestalten. Um die Potenziale, aber auch die Schwächen der MOOCs bewerten zu können, bedarf es aber einer differenzierten Betrachtung, als sie bisher stattgefunden hat. Dieser Band stellt Erfahrungsberichte und Beispiele aus deutschen Hochschulen oder mit deutscher Beteiligung vor und reflektiert das Phänomen der MOOCs unter didaktischen, historischen und bildungspolitischen Aspekten.

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We study the differential cross sections for electroweak gauge-boson and Higgs production at small and very small transverse-momentum qT. Large logarithms are resummed using soft-collinear effective theory. The collinear anomaly generates a non-perturbative scale q⁎, which protects the processes from receiving large long-distance hadronic contributions. A numerical comparison of our predictions with data on the transverse-momentum distribution in Z-boson production at the Tevatron and LHC is given.

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Stylonychia lemnae is a classical model single-celled eukaryote, and a quintessential ciliate typified by dimorphic nuclei: A small, germline micronucleus and a massive, vegetative macronucleus. The genome within Stylonychia's macronucleus has a very unusual architecture, comprised variably and highly amplified "nanochromosomes," each usually encoding a single gene with a minimal amount of surrounding noncoding DNA. As only a tiny fraction of the Stylonychia genes has been sequenced, and to promote research using this organism, we sequenced its macronuclear genome. We report the analysis of the 50.2-Mb draft S. lemnae macronuclear genome assembly, containing in excess of 16,000 complete nanochromosomes, assembled as less than 20,000 contigs. We found considerable conservation of fundamental genomic properties between S. lemnae and its close relative, Oxytricha trifallax, including nanochromosomal gene synteny, alternative fragmentation, and copy number. Protein domain searches in Stylonychia revealed two new telomere-binding protein homologs and the presence of linker histones. Among the diverse histone variants of S. lemnae and O. trifallax, we found divergent, coexpressed variants corresponding to four of the five core nucleosomal proteins (H1.2, H2A.6, H2B.4, and H3.7) suggesting that these ciliates may possess specialized nucleosomes involved in genome processing during nuclear differentiation. The assembly of the S. lemnae macronuclear genome demonstrates that largely complete, well-assembled highly fragmented genomes of similar size and complexity may be produced from one library and lane of Illumina HiSeq 2000 shotgun sequencing. The provision of the S. lemnae macronuclear genome sets the stage for future detailed experimental studies of chromatin-mediated, RNA-guided developmental genome rearrangements.

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A search for pair-produced massive coloured scalar particles decaying to a four-jet final state is performed by the ATLAS experiment at the LHC in proton-proton collisions at root s = 7 TeV. The analysed data sample corresponds to an integrated luminosity of 4.6 fb(-1). No deviation from the Standard Model is observed in the invariant mass spectrum of the two-jet pairs. A limit on the scalar gluon pair production cross section of 70 pb (10 pb) is obtained at the 95 % confidence level for a scalar gluon mass of 150 GeV (350 GeV). Interpreting these results as mass limits on scalar gluons, masses ranging from 150 GeV to 287 GeV are excluded at the 95 % confidence level.