TY - JOUR AB - The Arabidopsis thaliana central cell, the companion cell of the egg, undergoes DNA demethylation before fertilization, but the targeting preferences, mechanism, and biological significance of this process remain unclear. Here, we show that active DNA demethylation mediated by the DEMETER DNA glycosylase accounts for all of the demethylation in the central cell and preferentially targets small, AT-rich, and nucleosome-depleted euchromatic transposable elements. The vegetative cell, the companion cell of sperm, also undergoes DEMETER-dependent demethylation of similar sequences, and lack of DEMETER in vegetative cells causes reduced small RNA–directed DNA methylation of transposons in sperm. Our results demonstrate that demethylation in companion cells reinforces transposon methylation in plant gametes and likely contributes to stable silencing of transposable elements across generations. AU - Ibarra, Christian A. AU - Feng, Xiaoqi AU - Schoft, Vera K. AU - Hsieh, Tzung-Fu AU - Uzawa, Rie AU - Rodrigues, Jessica A. AU - Zemach, Assaf AU - Chumak, Nina AU - Machlicova, Adriana AU - Nishimura, Toshiro AU - Rojas, Denisse AU - Fischer, Robert L. AU - Tamaru, Hisashi AU - Zilberman, Daniel ID - 12198 IS - 6100 JF - Science KW - Multidisciplinary SN - 0036-8075 TI - Active DNA demethylation in plant companion cells reinforces transposon methylation in gametes VL - 337 ER - TY - JOUR AB - First we note that the best polynomial approximation to vertical bar x vertical bar on the set, which consists of an interval on the positive half-axis and a point on the negative half-axis, can be given by means of the classical Chebyshev polynomials. Then we explore the cases when a solution of the related problem on two intervals can be given in elementary functions. AU - Pausinger, Florian ID - 6588 IS - 1 JF - Journal of Mathematical Physics, Analysis, Geometry SN - 1812-9471 TI - Elementary solutions of the Bernstein problem on two intervals VL - 8 ER - TY - CONF AB - We introduce the idea of using an explicit triangle mesh to track the air/fluid interface in a smoothed particle hydrodynamics (SPH) simulator. Once an initial surface mesh is created, this mesh is carried forward in time using nearby particle velocities to advect the mesh vertices. The mesh connectivity remains mostly unchanged across time-steps; it is only modified locally for topology change events or for the improvement of triangle quality. In order to ensure that the surface mesh does not diverge from the underlying particle simulation, we periodically project the mesh surface onto an implicit surface defined by the physics simulation. The mesh surface gives us several advantages over previous SPH surface tracking techniques. We demonstrate a new method for surface tension calculations that clearly outperforms the state of the art in SPH surface tension for computer graphics. We also demonstrate a method for tracking detailed surface information (like colors) that is less susceptible to numerical diffusion than competing techniques. Finally, our temporally-coherent surface mesh allows us to simulate high-resolution surface wave dynamics without being limited by the particle resolution of the SPH simulation. AU - Yu, Jihun AU - Wojtan, Christopher J AU - Turk, Greg AU - Yap, Chee ID - 3123 IS - 2 SN - 0167-7055 T2 - Computer Graphics Forum TI - Explicit mesh surfaces for particle based fluids VL - 31 ER - TY - JOUR AB - Bibliothekare haben die Aufgabe, sich mit neuen Medienformen auseinanderzusetzen. AU - Danowski, Patrick ID - 3244 IS - 4 JF - BuB - Forum Bibliothek und Information SN - 1869 -1137 TI - Die Zeit des Abwartens ist vorbei! VL - 64 ER - TY - JOUR AB - Wie wandelt sich das Berufsbild in Wissenschaftlichen Bibliotheken? Patrick Danowski gibt seine Einschätzung ab. AU - Danowski, Patrick ID - 3243 IS - 1 JF - Büchereiperspektiven SN - 1607-7172 TI - Zwischen Technologie und Information VL - 2012 ER -