--- _id: '9014' abstract: - lang: eng text: In this Letter, we explore experimentally the phase behavior of a dense active suspension of self-propelled colloids. In addition to a solidlike and gaslike phase observed for high and low densities, a novel cluster phase is reported at intermediate densities. This takes the form of a stationary assembly of dense aggregates—resulting from a permanent dynamical merging and separation of active colloids—whose average size grows with activity as a linear function of the self-propelling velocity. While different possible scenarios can be considered to account for these observations—such as a generic velocity weakening instability recently put forward—we show that the experimental results are reproduced mathematically by a chemotactic aggregation mechanism, originally introduced to account for bacterial aggregation and accounting here for diffusiophoretic chemical interaction between colloidal swimmers. article_number: '268303' article_processing_charge: No article_type: letter_note author: - first_name: I. full_name: Theurkauff, I. last_name: Theurkauff - first_name: C. full_name: Cottin-Bizonne, C. last_name: Cottin-Bizonne - first_name: Jérémie A full_name: Palacci, Jérémie A id: 8fb92548-2b22-11eb-b7c1-a3f0d08d7c7d last_name: Palacci orcid: 0000-0002-7253-9465 - first_name: C. full_name: Ybert, C. last_name: Ybert - first_name: L. full_name: Bocquet, L. last_name: Bocquet citation: ama: Theurkauff I, Cottin-Bizonne C, Palacci JA, Ybert C, Bocquet L. Dynamic clustering in active colloidal suspensions with chemical signaling. Physical Review Letters. 2012;108(26). doi:10.1103/physrevlett.108.268303 apa: Theurkauff, I., Cottin-Bizonne, C., Palacci, J. A., Ybert, C., & Bocquet, L. (2012). Dynamic clustering in active colloidal suspensions with chemical signaling. Physical Review Letters. American Physical Society . https://doi.org/10.1103/physrevlett.108.268303 chicago: Theurkauff, I., C. Cottin-Bizonne, Jérémie A Palacci, C. Ybert, and L. Bocquet. “Dynamic Clustering in Active Colloidal Suspensions with Chemical Signaling.” Physical Review Letters. American Physical Society , 2012. https://doi.org/10.1103/physrevlett.108.268303. ieee: I. Theurkauff, C. Cottin-Bizonne, J. A. Palacci, C. Ybert, and L. Bocquet, “Dynamic clustering in active colloidal suspensions with chemical signaling,” Physical Review Letters, vol. 108, no. 26. American Physical Society , 2012. ista: Theurkauff I, Cottin-Bizonne C, Palacci JA, Ybert C, Bocquet L. 2012. Dynamic clustering in active colloidal suspensions with chemical signaling. Physical Review Letters. 108(26), 268303. mla: Theurkauff, I., et al. “Dynamic Clustering in Active Colloidal Suspensions with Chemical Signaling.” Physical Review Letters, vol. 108, no. 26, 268303, American Physical Society , 2012, doi:10.1103/physrevlett.108.268303. short: I. Theurkauff, C. Cottin-Bizonne, J.A. Palacci, C. Ybert, L. Bocquet, Physical Review Letters 108 (2012). date_created: 2021-01-19T10:26:59Z date_published: 2012-06-29T00:00:00Z date_updated: 2023-02-23T13:46:45Z day: '29' doi: 10.1103/physrevlett.108.268303 extern: '1' external_id: arxiv: - '1202.6264' pmid: - '23005020' intvolume: ' 108' issue: '26' language: - iso: eng main_file_link: - open_access: '1' url: https://arxiv.org/abs/1202.6264 month: '06' oa: 1 oa_version: Preprint pmid: 1 publication: Physical Review Letters publication_identifier: eissn: - '10797114' issn: - '00319007' publication_status: published publisher: 'American Physical Society ' quality_controlled: '1' scopus_import: '1' status: public title: Dynamic clustering in active colloidal suspensions with chemical signaling type: journal_article user_id: D865714E-FA4E-11E9-B85B-F5C5E5697425 volume: 108 year: '2012' ... --- _id: '91' abstract: - lang: eng text: 'We demonstrate how to appropriately estimate the zero-frequency (static) hyperpolarizability of an organic molecule from its charge distribution, and we explore applications of these estimates for identifying and evaluating new organic nonlinear optical (NLO) materials. First, we calculate hyperpolarizabilities from Hartree-Fock-derived charge distributions and find order-of-magnitude agreement with experimental values. We show that these simple arithmetic calculations will enable systematic searches for new organic NLO molecules. Second, we derive hyperpolarizabilities from crystallographic data using a multipolar charge-density analysis and find good agreement with empirical calculations. This demonstrates an experimental determination of the full static hyperpolarizability tensor in a solid-state sample. ' acknowledgement: This work was supported by The Winston Churchill Foundation of the United States (A.P.H., M.A.B.F., D.D.H.), The Royal Society via a University Research Fellowship (J.M.C.), and the University of New Brunswick via The Vice-Chancellor’s Research Chair (J.M.C.). article_number: '033512' author: - first_name: Andrew P full_name: Higginbotham, Andrew P id: 4AD6785A-F248-11E8-B48F-1D18A9856A87 last_name: Higginbotham orcid: 0000-0003-2607-2363 - first_name: Jacqueline full_name: Cole, Jacqueline last_name: Cole - first_name: Martin full_name: Blood Forsythe, Martin last_name: Blood Forsythe - first_name: Daniel full_name: Hickstein, Daniel last_name: Hickstein citation: ama: Higginbotham AP, Cole J, Blood Forsythe M, Hickstein D. Identifying and evaluating organic nonlinear optical materials via molecular moments. Journal of Applied Physics. 2012;111(3). doi:10.1063/1.3678593 apa: Higginbotham, A. P., Cole, J., Blood Forsythe, M., & Hickstein, D. (2012). Identifying and evaluating organic nonlinear optical materials via molecular moments. Journal of Applied Physics. American Institute of Physics. https://doi.org/10.1063/1.3678593 chicago: Higginbotham, Andrew P, Jacqueline Cole, Martin Blood Forsythe, and Daniel Hickstein. “Identifying and Evaluating Organic Nonlinear Optical Materials via Molecular Moments.” Journal of Applied Physics. American Institute of Physics, 2012. https://doi.org/10.1063/1.3678593. ieee: A. P. Higginbotham, J. Cole, M. Blood Forsythe, and D. Hickstein, “Identifying and evaluating organic nonlinear optical materials via molecular moments,” Journal of Applied Physics, vol. 111, no. 3. American Institute of Physics, 2012. ista: Higginbotham AP, Cole J, Blood Forsythe M, Hickstein D. 2012. Identifying and evaluating organic nonlinear optical materials via molecular moments. Journal of Applied Physics. 111(3), 033512. mla: Higginbotham, Andrew P., et al. “Identifying and Evaluating Organic Nonlinear Optical Materials via Molecular Moments.” Journal of Applied Physics, vol. 111, no. 3, 033512, American Institute of Physics, 2012, doi:10.1063/1.3678593. short: A.P. Higginbotham, J. Cole, M. Blood Forsythe, D. Hickstein, Journal of Applied Physics 111 (2012). date_created: 2018-12-11T11:44:35Z date_published: 2012-02-07T00:00:00Z date_updated: 2021-01-12T08:21:50Z day: '07' doi: 10.1063/1.3678593 extern: '1' intvolume: ' 111' issue: '3' language: - iso: eng month: '02' oa_version: None publication: Journal of Applied Physics publication_status: published publisher: American Institute of Physics publist_id: '7963' quality_controlled: '1' status: public title: Identifying and evaluating organic nonlinear optical materials via molecular moments type: journal_article user_id: 3E5EF7F0-F248-11E8-B48F-1D18A9856A87 volume: 111 year: '2012' ... --- _id: '9142' abstract: - lang: eng text: "In models of radiative–convective equilibrium it is known that convection can spontaneously aggregate into one single localized moist region if the domain is large enough. The large changes in the mean climate state and radiative fluxes accompanying this self-aggregation raise questions as to what simulations at lower resolutions with parameterized convection, in similar homogeneous geometries, should be expected to produce to be considered successful in mimicking a cloud-resolving model.\r\nThe authors investigate this self-aggregation in a nonrotating, three-dimensional cloud-resolving model on a square domain without large-scale forcing. It is found that self-aggregation is sensitive not only to the domain size, but also to the horizontal resolution. With horizontally homogeneous initial conditions, convective aggregation only occurs on domains larger than about 200km and with resolutions coarser than about 2km in the model examined. The system exhibits hysteresis, so that with aggregated initial conditions, convection remains aggregated even at our finest resolution, 500m, as long as the domain is greater than 200–300km.\r\nThe sensitivity of self-aggregation to resolution and domain size in this model is due to the sensitivity of the distribution of low clouds to these two parameters. Indeed, the mechanism responsible for the aggregation of convection is the dynamical response to the longwave radiative cooling from low clouds. Strong longwave cooling near cloud top in dry regions forces downward motion, which by continuity generates inflow near cloud top and near-surface outflow from dry regions. This circulation results in the net export of moist static energy from regions with low moist static energy, yielding a positive feedback." article_processing_charge: No article_type: original author: - first_name: Caroline J full_name: Muller, Caroline J id: f978ccb0-3f7f-11eb-b193-b0e2bd13182b last_name: Muller orcid: 0000-0001-5836-5350 - first_name: Isaac M. full_name: Held, Isaac M. last_name: Held citation: ama: Muller CJ, Held IM. Detailed investigation of the self-aggregation of convection in cloud-resolving simulations. Journal of the Atmospheric Sciences. 2012;69(8):2551-2565. doi:10.1175/jas-d-11-0257.1 apa: Muller, C. J., & Held, I. M. (2012). Detailed investigation of the self-aggregation of convection in cloud-resolving simulations. Journal of the Atmospheric Sciences. American Meteorological Society. https://doi.org/10.1175/jas-d-11-0257.1 chicago: Muller, Caroline J, and Isaac M. Held. “Detailed Investigation of the Self-Aggregation of Convection in Cloud-Resolving Simulations.” Journal of the Atmospheric Sciences. American Meteorological Society, 2012. https://doi.org/10.1175/jas-d-11-0257.1. ieee: C. J. Muller and I. M. Held, “Detailed investigation of the self-aggregation of convection in cloud-resolving simulations,” Journal of the Atmospheric Sciences, vol. 69, no. 8. American Meteorological Society, pp. 2551–2565, 2012. ista: Muller CJ, Held IM. 2012. Detailed investigation of the self-aggregation of convection in cloud-resolving simulations. Journal of the Atmospheric Sciences. 69(8), 2551–2565. mla: Muller, Caroline J., and Isaac M. Held. “Detailed Investigation of the Self-Aggregation of Convection in Cloud-Resolving Simulations.” Journal of the Atmospheric Sciences, vol. 69, no. 8, American Meteorological Society, 2012, pp. 2551–65, doi:10.1175/jas-d-11-0257.1. short: C.J. Muller, I.M. Held, Journal of the Atmospheric Sciences 69 (2012) 2551–2565. date_created: 2021-02-15T14:39:03Z date_published: 2012-08-01T00:00:00Z date_updated: 2022-01-24T13:49:41Z day: '01' doi: 10.1175/jas-d-11-0257.1 extern: '1' intvolume: ' 69' issue: '8' keyword: - Atmospheric Science language: - iso: eng main_file_link: - open_access: '1' url: https://doi.org/10.1175/JAS-D-11-0257.1 month: '08' oa: 1 oa_version: Published Version page: 2551-2565 publication: Journal of the Atmospheric Sciences publication_identifier: issn: - 0022-4928 - 1520-0469 publication_status: published publisher: American Meteorological Society quality_controlled: '1' status: public title: Detailed investigation of the self-aggregation of convection in cloud-resolving simulations type: journal_article user_id: 8b945eb4-e2f2-11eb-945a-df72226e66a9 volume: 69 year: '2012' ... --- _id: '9451' abstract: - lang: eng text: 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. article_processing_charge: No article_type: original author: - first_name: Christian A. full_name: Ibarra, Christian A. last_name: Ibarra - first_name: Xiaoqi full_name: Feng, Xiaoqi last_name: Feng - first_name: Vera K. full_name: Schoft, Vera K. last_name: Schoft - first_name: Tzung-Fu full_name: Hsieh, Tzung-Fu last_name: Hsieh - first_name: Rie full_name: Uzawa, Rie last_name: Uzawa - first_name: Jessica A. full_name: Rodrigues, Jessica A. last_name: Rodrigues - first_name: Assaf full_name: Zemach, Assaf last_name: Zemach - first_name: Nina full_name: Chumak, Nina last_name: Chumak - first_name: Adriana full_name: Machlicova, Adriana last_name: Machlicova - first_name: Toshiro full_name: Nishimura, Toshiro last_name: Nishimura - first_name: Denisse full_name: Rojas, Denisse last_name: Rojas - first_name: Robert L. full_name: Fischer, Robert L. last_name: Fischer - first_name: Hisashi full_name: Tamaru, Hisashi last_name: Tamaru - first_name: Daniel full_name: Zilberman, Daniel id: 6973db13-dd5f-11ea-814e-b3e5455e9ed1 last_name: Zilberman orcid: 0000-0002-0123-8649 citation: ama: Ibarra CA, Feng X, Schoft VK, et al. Active DNA demethylation in plant companion cells reinforces transposon methylation in gametes. Science. 2012;337(6100):1360-1364. doi:10.1126/science.1224839 apa: Ibarra, C. A., Feng, X., Schoft, V. K., Hsieh, T.-F., Uzawa, R., Rodrigues, J. A., … Zilberman, D. (2012). Active DNA demethylation in plant companion cells reinforces transposon methylation in gametes. Science. American Association for the Advancement of Science. https://doi.org/10.1126/science.1224839 chicago: Ibarra, Christian A., Xiaoqi Feng, Vera K. Schoft, Tzung-Fu Hsieh, Rie Uzawa, Jessica A. Rodrigues, Assaf Zemach, et al. “Active DNA Demethylation in Plant Companion Cells Reinforces Transposon Methylation in Gametes.” Science. American Association for the Advancement of Science, 2012. https://doi.org/10.1126/science.1224839. ieee: C. A. Ibarra et al., “Active DNA demethylation in plant companion cells reinforces transposon methylation in gametes,” Science, vol. 337, no. 6100. American Association for the Advancement of Science, pp. 1360–1364, 2012. ista: Ibarra CA, Feng X, Schoft VK, Hsieh T-F, Uzawa R, Rodrigues JA, Zemach A, Chumak N, Machlicova A, Nishimura T, Rojas D, Fischer RL, Tamaru H, Zilberman D. 2012. Active DNA demethylation in plant companion cells reinforces transposon methylation in gametes. Science. 337(6100), 1360–1364. mla: Ibarra, Christian A., et al. “Active DNA Demethylation in Plant Companion Cells Reinforces Transposon Methylation in Gametes.” Science, vol. 337, no. 6100, American Association for the Advancement of Science, 2012, pp. 1360–64, doi:10.1126/science.1224839. short: C.A. Ibarra, X. Feng, V.K. Schoft, T.-F. Hsieh, R. Uzawa, J.A. Rodrigues, A. Zemach, N. Chumak, A. Machlicova, T. Nishimura, D. Rojas, R.L. Fischer, H. Tamaru, D. Zilberman, Science 337 (2012) 1360–1364. date_created: 2021-06-04T07:51:31Z date_published: 2012-09-14T00:00:00Z date_updated: 2021-12-14T08:28:51Z day: '14' ddc: - '580' department: - _id: DaZi doi: 10.1126/science.1224839 extern: '1' external_id: pmid: - '22984074' has_accepted_license: '1' intvolume: ' 337' issue: '6100' language: - iso: eng main_file_link: - open_access: '1' url: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4034762/ month: '09' oa: 1 oa_version: Published Version page: 1360-1364 pmid: 1 publication: Science publication_identifier: eissn: - 1095-9203 issn: - 0036-8075 publication_status: published publisher: American Association for the Advancement of Science quality_controlled: '1' scopus_import: '1' status: public title: Active DNA demethylation in plant companion cells reinforces transposon methylation in gametes type: journal_article user_id: 8b945eb4-e2f2-11eb-945a-df72226e66a9 volume: 337 year: '2012' ... --- _id: '9535' abstract: - lang: eng text: The most well-studied function of DNA methylation in eukaryotic cells is the transcriptional silencing of genes and transposons. More recent results showed that many eukaryotes methylate the bodies of genes as well and that this methylation correlates with transcriptional activity rather than repression. The purpose of gene body methylation remains mysterious, but is potentially related to the histone variant H2A.Z. Studies in plants and animals have shown that the genome-wide distributions of H2A.Z and DNA methylation are strikingly anticorrelated. Furthermore, we and other investigators have shown that this relationship is likely to be the result of an ancient but unknown mechanism by which DNA methylation prevents the incorporation of H2A.Z. Recently, we discovered strong correlations between the presence of H2A.Z within gene bodies, the degree to which a gene's expression varies across tissue types or environmental conditions, and transcriptional misregulation in an h2a.z mutant. We propose that one basal function of gene body methylation is the establishment of constitutive expression patterns within housekeeping genes by excluding H2A.Z from their bodies. article_processing_charge: No article_type: review author: - first_name: D. full_name: Coleman-Derr, D. last_name: Coleman-Derr - first_name: Daniel full_name: Zilberman, Daniel id: 6973db13-dd5f-11ea-814e-b3e5455e9ed1 last_name: Zilberman orcid: 0000-0002-0123-8649 citation: ama: Coleman-Derr D, Zilberman D. DNA methylation, H2A.Z, and the regulation of constitutive expression. Cold Spring Harbor Symposia on Quantitative Biology. 2012;77:147-154. doi:10.1101/sqb.2012.77.014944 apa: Coleman-Derr, D., & Zilberman, D. (2012). DNA methylation, H2A.Z, and the regulation of constitutive expression. Cold Spring Harbor Symposia on Quantitative Biology. Cold Spring Harbor Laboratory Press. https://doi.org/10.1101/sqb.2012.77.014944 chicago: Coleman-Derr, D., and Daniel Zilberman. “DNA Methylation, H2A.Z, and the Regulation of Constitutive Expression.” Cold Spring Harbor Symposia on Quantitative Biology. Cold Spring Harbor Laboratory Press, 2012. https://doi.org/10.1101/sqb.2012.77.014944. ieee: D. Coleman-Derr and D. Zilberman, “DNA methylation, H2A.Z, and the regulation of constitutive expression,” Cold Spring Harbor Symposia on Quantitative Biology, vol. 77. Cold Spring Harbor Laboratory Press, pp. 147–154, 2012. ista: Coleman-Derr D, Zilberman D. 2012. DNA methylation, H2A.Z, and the regulation of constitutive expression. Cold Spring Harbor Symposia on Quantitative Biology. 77, 147–154. mla: Coleman-Derr, D., and Daniel Zilberman. “DNA Methylation, H2A.Z, and the Regulation of Constitutive Expression.” Cold Spring Harbor Symposia on Quantitative Biology, vol. 77, Cold Spring Harbor Laboratory Press, 2012, pp. 147–54, doi:10.1101/sqb.2012.77.014944. short: D. Coleman-Derr, D. Zilberman, Cold Spring Harbor Symposia on Quantitative Biology 77 (2012) 147–154. date_created: 2021-06-08T13:01:23Z date_published: 2012-12-18T00:00:00Z date_updated: 2021-12-14T08:33:09Z day: '18' department: - _id: DaZi doi: 10.1101/sqb.2012.77.014944 extern: '1' external_id: pmid: - '23250988' intvolume: ' 77' language: - iso: eng main_file_link: - open_access: '1' url: https://doi.org/10.1101/sqb.2012.77.014944 month: '12' oa: 1 oa_version: Published Version page: 147-154 pmid: 1 publication: Cold Spring Harbor Symposia on Quantitative Biology publication_identifier: eissn: - 1943-4456 issn: - 0091-7451 publication_status: published publisher: Cold Spring Harbor Laboratory Press quality_controlled: '1' scopus_import: '1' status: public title: DNA methylation, H2A.Z, and the regulation of constitutive expression type: journal_article user_id: 8b945eb4-e2f2-11eb-945a-df72226e66a9 volume: 77 year: '2012' ...