TY - JOUR AB - The root cap protects the stem cell niche of angiosperm roots from damage. In Arabidopsis, lateral root cap (LRC) cells covering the meristematic zone are regularly lost through programmed cell death, while the outermost layer of the root cap covering the tip is repeatedly sloughed. Efficient coordination with stem cells producing new layers is needed to maintain a constant size of the cap. We present a signalling pair, the peptide IDA-LIKE1 (IDL1) and its receptor HAESA-LIKE2 (HSL2), mediating such communication. Live imaging over several days characterized this process from initial fractures in LRC cell files to full separation of a layer. Enhanced expression of IDL1 in the separating root cap layers resulted in increased frequency of sloughing, balanced with generation of new layers in a HSL2-dependent manner. Transcriptome analyses linked IDL1-HSL2 signalling to the transcription factors BEARSKIN1/2 and genes associated with programmed cell death. Mutations in either IDL1 or HSL2 slowed down cell division, maturation and separation. Thus, IDL1-HSL2 signalling potentiates dynamic regulation of the homeostatic balance between stem cell division and sloughing activity. AU - Shi, Chun Lin AU - Von Wangenheim, Daniel AU - Herrmann, Ullrich AU - Wildhagen, Mari AU - Kulik, Ivan AU - Kopf, Andreas AU - Ishida, Takashi AU - Olsson, Vilde AU - Anker, Mari Kristine AU - Albert, Markus AU - Butenko, Melinka A AU - Felix, Georg AU - Sawa, Shinichiro AU - Claassen, Manfred AU - Friml, Jirí AU - Aalen, Reidunn B ID - 146 IS - 8 JF - Nature Plants TI - The dynamics of root cap sloughing in Arabidopsis is regulated by peptide signalling VL - 4 ER - TY - JOUR AB - People sometimes make their admirable deeds and accomplishments hard to spot, such as by giving anonymously or avoiding bragging. Such ‘buried’ signals are hard to reconcile with standard models of signalling or indirect reciprocity, which motivate costly pro-social behaviour by reputational gains. To explain these phenomena, we design a simple game theory model, which we call the signal-burying game. This game has the feature that senders can bury their signal by deliberately reducing the probability of the signal being observed. If the signal is observed, however, it is identified as having been buried. We show under which conditions buried signals can be maintained, using static equilibrium concepts and calculations of the evolutionary dynamics. We apply our analysis to shed light on a number of otherwise puzzling social phenomena, including modesty, anonymous donations, subtlety in art and fashion, and overeagerness. AU - Hoffman, Moshe AU - Hilbe, Christian AU - Nowak, Martin ID - 293 JF - Nature Human Behaviour TI - The signal-burying game can explain why we obscure positive traits and good deeds VL - 2 ER - TY - JOUR AB - The derivation of effective evolution equations is central to the study of non-stationary quantum many-body systems, and widely used in contexts such as superconductivity, nuclear physics, Bose–Einstein condensation and quantum chemistry. We reformulate the Dirac–Frenkel approximation principle in terms of reduced density matrices and apply it to fermionic and bosonic many-body systems. We obtain the Bogoliubov–de Gennes and Hartree–Fock–Bogoliubov equations, respectively. While we do not prove quantitative error estimates, our formulation does show that the approximation is optimal within the class of quasifree states. Furthermore, we prove well-posedness of the Bogoliubov–de Gennes equations in energy space and discuss conserved quantities AU - Benedikter, Niels P AU - Sok, Jérémy AU - Solovej, Jan ID - 455 IS - 4 JF - Annales Henri Poincare TI - The Dirac–Frenkel principle for reduced density matrices and the Bogoliubov–de Gennes equations VL - 19 ER - TY - JOUR AB - The interface of physics and biology pro-vides a fruitful environment for generatingnew concepts and exciting ways forwardto understanding living matter. Examplesof successful studies include the estab-lishment and readout of morphogen gra-dients during development, signal pro-cessing in protein and genetic networks,the role of fluctuations in determining thefates of cells and tissues, and collectiveeffects in proteins and in tissues. It is nothard to envision that significant further ad-vances will translate to societal benefitsby initiating the development of new de-vices and strategies for curing disease.However, research at the interface posesvarious challenges, in particular for youngscientists, and current institutions arerarely designed to facilitate such scientificprograms. In this Letter, we propose aninternational initiative that addressesthese challenges through the establish-ment of a worldwide network of platformsfor cross-disciplinary training and incuba-tors for starting new collaborations. AU - Bauer, Guntram AU - Fakhri, Nikta AU - Kicheva, Anna AU - Kondev, Jané AU - Kruse, Karsten AU - Noji, Hiroyuki AU - Riveline, Daniel AU - Saunders, Timothy AU - Thatta, Mukund AU - Wieschaus, Eric ID - 314 IS - 4 JF - Cell Systems TI - The science of living matter for tomorrow VL - 6 ER - TY - JOUR AB - We re-examine the model of Kirkpatrick and Barton for the spread of an inversion into a local population. This model assumes that local selection maintains alleles at two or more loci, despite immigration of alternative alleles at these loci from another population. We show that an inversion is favored because it prevents the breakdown of linkage disequilibrium generated by migration; the selective advantage of an inversion is proportional to the amount of recombination between the loci involved, as in other cases where inversions are selected for. We derive expressions for the rate of spread of an inversion; when the loci covered by the inversion are tightly linked, these conditions deviate substantially from those proposed previously, and imply that an inversion can then have only a small advantage. AU - Charlesworth, Brian AU - Barton, Nicholas H ID - 565 IS - 1 JF - Genetics TI - The spread of an inversion with migration and selection VL - 208 ER -