@article{14007, abstract = {In a recent article by Hockett et al (2016 J. Phys. B: At. Mol. Opt. Phys. 49 095602), time delays arising in the context of molecular single-photon ionization are investigated from a theoretical point of view. We argue that one of the central equations given in this article is incorrect and present a reformulation that is consistent with the established treatment of angle-dependent scattering delays (Eisenbud 1948 PhD Thesis Princeton University; Wigner 1955 Phys. Rev. 98 145–7; Smith 1960 Phys. Rev. 118 349–6; Nussenzveig 1972 Phys. Rev. D 6 1534–42).}, author = {Baykusheva, Denitsa Rangelova and Wörner, Hans Jakob}, issn = {1361-6455}, journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, keywords = {Condensed Matter Physics, Atomic and Molecular Physics, and Optics}, number = {7}, publisher = {IOP Publishing}, title = {{Comment on ‘Time delays in molecular photoionization’}}, doi = {10.1088/1361-6455/aa62b5}, volume = {50}, year = {2017}, } @article{14009, abstract = {Attosecond delays between photoelectron wave packets emitted from different electronic shells are now well established. Is there any delay between electrons originating from the same electronic shell but leaving the cation in different fine-structure states? This question is relevant for all attosecond photoemission studies involving heavy elements, be it atoms, molecules or solids. We answer this fundamental question by measuring energy-dependent delays between photoelectron wave packets associated with the 2P3/2 and 2P1/2 components of the electronic groundstates of Xe+ and Kr+. We observe delays reaching up to 33±6 as in the case of Xe. Our results are compared with two state-of-the-art theories. Whereas both theories quantitatively agree with the results obtained for Kr, neither of them fully reproduces the experimental results in Xe. Performing delay measurements very close to the ionization thresholds, we compare the agreement of several analytical formulas for the continuum-continuum delays with experimental data. Our results show an important influence of spin-orbit coupling on attosecond photoionization delays, highlight the requirement for additional theory development, and offer a precision benchmark for such work.}, author = {Jordan, I. and Huppert, M. and Pabst, S. and Kheifets, A. S. and Baykusheva, Denitsa Rangelova and Wörner, H. J.}, issn = {2469-9934}, journal = {Physical Review A}, number = {1}, publisher = {American Physical Society}, title = {{Spin-orbit delays in photoemission}}, doi = {10.1103/physreva.95.013404}, volume = {95}, year = {2017}, } @article{17696, abstract = {We utilize cosmological hydrodynamic simulations to study the formation of Population III (Pop III) stars in dark matter halos exposed to strong ionizing radiation. We simulate the formation of three halos subjected to a wide range of ionizing fluxes, and find that for high flux, ionization and photoheating can delay gas collapse and star formation up to halo masses significantly larger than the atomic cooling threshold. The threshold halo mass at which gas first collapses and cools increases with ionizing flux for intermediate values, and saturates at a value approximately an order of magnitude above the atomic cooling threshold for extremely high flux (e.g. ≈5×108 M⊙ at z≈6). This behavior can be understood in terms of photoheating, ionization/recombination, and Lyα cooling in the pressure-supported, self-shielded gas core at the center of the growing dark matter halo. We examine the spherically-averaged radial velocity profiles of collapsing gas and find that a gas mass of up to ≈106 M⊙ can reach the central regions within 3 Myr, providing an upper limit on the amount of massive Pop III stars that can form. The ionizing radiation increases this limit by a factor of a few compared to strong Lyman-Werner (LW) radiation alone. We conclude that the bright HeII 1640 Å emission recently observed from the high-redshift galaxy CR7 cannot be explained by Pop III stars alone. However, in some halos, a sufficient number of Pop III stars may form to be detectable with future telescopes such as the James Webb Space Telescope (JWST).}, author = {Visbal, Eli and Bryan, Greg L. and Haiman, Zoltán}, issn = {0035-8711}, journal = {Monthly Notices of the Royal Astronomical Society}, number = {2}, pages = {1456--1465}, publisher = {Oxford University Press}, title = {{What is the maximum mass of a Population III galaxy?}}, doi = {10.1093/mnras/stx909}, volume = {469}, year = {2017}, } @article{17698, abstract = {Gaseous circumbinary accretion discs provide a promising mechanism to facilitate the mergers of supermassive black holes (SMBHs) in galactic nuclei. We measure the torques exerted on accreting SMBH binaries, using 2D, isothermal, moving-mesh, viscous hydrodynamical simulations of circumbinary accretion discs. Our computational domain includes the entire inner region of the circumbinary disk with the individual black holes (BHs) included as point masses on the grid and a sink prescription to model accretion onto each BH. The BHs each acquire their own well-resolved accretion discs ("minidiscs"). We explore a range of mass removal rates for the sink prescription removing gas from the central regions of the minidiscs. We find that the torque exerted on the binary is primarily gravitational, and dominated by the gas orbiting close behind and ahead of the individual BHs. The torques from the distorted circumbinary disc farther out and from the direct accretion of angular momentum are subdominant. The torques are sensitive to the sink prescription: slower sinks result in more gas accumulating near the BHs and more negative torques, driving the binary to merger more rapidly. For faster sinks, the torques are less negative and eventually turn positive (for unphysically fast sinks). When the minidiscs are modeled as standard alpha discs, our results are insensitive to the choice of sink radius. Scaling the simulations to a binary orbital period tbin = 1yr and background disc accretion rate Mdot = 0.3MEdd in Eddington units, the binary inspirals on a timescale of 3X10^6 years, irrespective of the SMBH masses. For binaries with total mass <10^7Msun, this is shorter than the inspiral time due to gravitational wave (GW) emission alone, implying that gas discs will have a significant impact on the SMBH binary population and can affect the GW signal for Pulsar Timing Arrays.}, author = {Tang, Yike and MacFadyen, Andrew and Haiman, Zoltán}, issn = {0035-8711}, journal = {Monthly Notices of the Royal Astronomical Society}, number = {4}, pages = {4258--4267}, publisher = {Oxford University Press}, title = {{On the orbital evolution of supermassive black hole binaries with circumbinary accretion discs}}, doi = {10.1093/mnras/stx1130}, volume = {469}, year = {2017}, } @article{17949, abstract = {Single-molecule electronic devices provide researchers with an unprecedented ability to relate novel physical phenomena to molecular chemical structures. Typically, conjugated aromatic molecular backbones are relied upon to create electronic devices, where the aromaticity of the building blocks is used to enhance conductivity. We capitalize on the classical physical organic chemistry concept of Hückel antiaromaticity by demonstrating a single-molecule switch that exhibits low conductance in the neutral state and, upon electrochemical oxidation, reversibly switches to an antiaromatic high-conducting structure. We form single-molecule devices using the scanning tunneling microscope–based break-junction technique and observe an on/off ratio of ~70 for a thiophenylidene derivative that switches to an antiaromatic state with 6-4-6-π electrons. Through supporting nuclear magnetic resonance measurements, we show that the doubly oxidized core has antiaromatic character and we use density functional theory calculations to rationalize the origin of the high-conductance state for the oxidized single-molecule junction. Together, our work demonstrates how the concept of antiaromaticity can be exploited to create single-molecule devices that are highly conducting.}, author = {Yin, Xiaodong and Zang, Yaping and Zhu, Liangliang and Low, Jonathan Z. and Liu, Zhen-Fei and Cui, Jing and Neaton, Jeffrey B. and Venkataraman, Latha and Campos, Luis M.}, issn = {2375-2548}, journal = {Science Advances}, number = {10}, publisher = {American Association for the Advancement of Science}, title = {{A reversible single-molecule switch based on activated antiaromaticity}}, doi = {10.1126/sciadv.aao2615}, volume = {3}, year = {2017}, } @article{8452, abstract = {During spore formation in Bacillus subtilis a transenvelope complex is assembled across the double membrane that separates the mother cell and forespore. This complex (called the “A–Q complex”) is required to maintain forespore development and is composed of proteins with remote homology to components of type II, III, and IV secretion systems found in Gram-negative bacteria. Here, we show that one of these proteins, SpoIIIAG, which has remote homology to ring-forming proteins found in type III secretion systems, assembles into an oligomeric ring in the periplasmic-like space between the two membranes. Three-dimensional reconstruction of images generated by cryo-electron microscopy indicates that the SpoIIIAG ring has a cup-and-saucer architecture with a 6-nm central pore. Structural modeling of SpoIIIAG generated a 24-member ring with dimensions similar to those of the EM-derived saucer. Point mutations in the predicted oligomeric interface disrupted ring formation in vitro and impaired forespore gene expression and efficient spore formation in vivo. Taken together, our data provide strong support for the model in which the A–Q transenvelope complex contains a conduit that connects the mother cell and forespore. We propose that a set of stacked rings spans the intermembrane space, as has been found for type III secretion systems.}, author = {Rodrigues, Christopher D. A. and Henry, Xavier and Neumann, Emmanuelle and Kurauskas, Vilius and Bellard, Laure and Fichou, Yann and Schanda, Paul and Schoehn, Guy and Rudner, David Z. and Morlot, Cecile}, issn = {0027-8424}, journal = {Proceedings of the National Academy of Sciences}, number = {41}, pages = {11585--11590}, publisher = {National Academy of Sciences}, title = {{A ring-shaped conduit connects the mother cell and forespore during sporulation in Bacillus subtilis}}, doi = {10.1073/pnas.1609604113}, volume = {113}, year = {2016}, } @article{7294, abstract = {Mesoporous nanocrystalline TiO2 and TiO2–V2O5 microspheres were prepared by non-hydrolytic sol–gel from TiCl4, VOCl3, and iPr2O at 110 °C without any solvent or additives. The samples were characterized by elemental analysis, X-ray diffraction, Raman spectroscopy, scanning electron microscopy, nitrogen physisorption, and impedance measurements. At low vanadium loadings, only TiO2 anatase was detected, and V2O5 scherbinaite was also detected at high vanadium loadings. The texture of the samples depended on the V loading, but all the samples appeared built of primary nanoparticles (≈10–20 nm in size) that aggregate to form mesoporous micron-sized spheres. The lithium insertion properties of these materials were evaluated by galvanostatic measurements taken using coin-type cells, in view of their application as electrode for rechargeable Li-ion batteries. The mesoporous TiO2 microspheres showed good performances, with a specific reversible capacity of 145 and 128 mAh g−1 at C/2 and C, respectively (C = 335.6 mA g−1), good coulombic efficiency, and a moderate capacity fade (6 %) from the 2nd to the 20th cycle at C/20. Although the addition of V effectively increased the electronic conductivity of the powders, the specific reversible capacity and cycling performances of the TiO2–V2O5 samples were only minimally improved for a 5 at% V loading and were lower at higher V loading.}, author = {Escamilla-Pérez, A. M. and Louvain, N. and Kaschowitz, M. and Freunberger, Stefan Alexander and Fontaine, O. and Boury, B. and Brun, N. and Mutin, P. H.}, issn = {0928-0707}, journal = {Journal of Sol-Gel Science and Technology}, number = {2}, pages = {270--278}, publisher = {Springer Nature}, title = {{Lithium insertion properties of mesoporous nanocrystalline TiO2 and TiO2–V2O5 microspheres prepared by non-hydrolytic sol–gel}}, doi = {10.1007/s10971-016-4037-9}, volume = {79}, year = {2016}, } @inproceedings{5806, abstract = {Although the concept of functional plane for naive plane is studied and reported in the literature in great detail, no similar study is yet found for naive sphere. This article exposes the first study in this line, opening up further prospects of analyzing the topological properties of sphere in the discrete space. We show that each quadraginta octant Q of a naive sphere forms a bijection with its projected pixel set on a unique coordinate plane, which thereby serves as the functional plane of Q, and hence gives rise to merely mono-jumps during back projection. The other two coordinate planes serve as para-functional and dia-functional planes for Q, as the former is ‘mono-jumping’ but not bijective, whereas the latter holds neither of the two. Owing to this, the quadraginta octants form symmetry groups and subgroups with equivalent jump conditions. We also show a potential application in generating a special class of discrete 3D circles based on back projection and jump bridging by Steiner voxels. A circle in this class possesses 4-symmetry, uniqueness, and bounded distance from the underlying real sphere and real plane.}, author = {Biswas, Ranita and Bhowmick, Partha}, booktitle = {Discrete Geometry for Computer Imagery}, isbn = {978-3-319-32359-6}, issn = {0302-9743}, location = {Nantes, France}, pages = {256--267}, publisher = {Springer Nature}, title = {{On functionality of quadraginta octants of naive sphere with application to circle drawing}}, doi = {10.1007/978-3-319-32360-2_20}, volume = {9647}, year = {2016}, } @inproceedings{482, abstract = {Nonlinear electro-optical conversion of microwave radiation into the optical telecommunication band is achieved within a crystalline whispering gallery mode resonator, reaching 0.1% photon number conversion efficiency with MHz bandwidth.}, author = {Rueda, Alfredo and Sedlmeir, Florian and Collodo, Michele and Vogl, Ulrich and Stiller, Birgit and Schunk, Gerhard and Strekalov, Dmitry and Marquardt, Christoph and Fink, Johannes M and Painter, Oskar and Leuchs, Gerd and Schwefel, Harald}, location = {Sydney, Australia}, publisher = {Optica Publishing Group}, title = {{Nonlinear single sideband microwave to optical conversion using an electro-optic WGM-resonator}}, doi = {10.1364/NP.2016.NTh3A.6}, year = {2016}, } @misc{5551, abstract = {Data from array experiments investigating pollinator behaviour on snapdragons in controlled conditions, and their effect on plant mating. Data were collected as part of Tom Ellis' PhD thesis , submitted February 2016. We placed a total of 36 plants in a grid inside a closed organza tent, with a single hive of commercially bred bumblebees (Bombus hortorum). We used only the yellow-flowered Antirrhinum majus striatum and the magenta-flowered Antirrhinum majus pseudomajus, at ratios of 6:36, 12:24, 18:18, 24:12 and 30:6. After 24 hours to learn how to deal with snapdragons, I observed pollinators foraging on plants, and recorded the transitions between plants. Thereafter seeds on plants were allowed to develops. A sample of these were grown to maturity when their flower colour could be determined, and they were scored as yellow, magenta, or hybrid.}, author = {Ellis, Thomas}, publisher = {Institute of Science and Technology Austria}, title = {{Data on pollinator observations and offpsring phenotypes}}, doi = {10.15479/AT:ISTA:35}, year = {2016}, } @misc{5557, abstract = {Small synthetic discrete tomography problems. Sizes are 32x32, 64z64 and 256x256. Projection angles are 2, 4, and 6. Number of labels are 3 and 5.}, author = {Swoboda, Paul}, keywords = {discrete tomography}, publisher = {Institute of Science and Technology Austria}, title = {{Synthetic discrete tomography problems}}, doi = {10.15479/AT:ISTA:46}, year = {2016}, } @inproceedings{11834, abstract = {We present a deterministic incremental algorithm for exactly maintaining the size of a minimum cut with ~O(1) amortized time per edge insertion and O(1) query time. This result partially answers an open question posed by Thorup [Combinatorica 2007]. It also stays in sharp contrast to a polynomial conditional lower-bound for the fully-dynamic weighted minimum cut problem. Our algorithm is obtained by combining a recent sparsification technique of Kawarabayashi and Thorup [STOC 2015] and an exact incremental algorithm of Henzinger [J. of Algorithm 1997]. We also study space-efficient incremental algorithms for the minimum cut problem. Concretely, we show that there exists an O(n log n/epsilon^2) space Monte-Carlo algorithm that can process a stream of edge insertions starting from an empty graph, and with high probability, the algorithm maintains a (1+epsilon)-approximation to the minimum cut. The algorithm has ~O(1) amortized update-time and constant query-time.}, author = {Goranci, Gramoz and Henzinger, Monika H and Thorup, Mikkel}, booktitle = {24th Annual European Symposium on Algorithms}, isbn = {978-3-95977-015-6}, issn = {1868-8969}, location = {Aarhus, Denmark}, publisher = {Schloss Dagstuhl - Leibniz-Zentrum für Informatik}, title = {{Incremental exact min-cut in poly-logarithmic amortized update time}}, doi = {10.4230/LIPICS.ESA.2016.46}, volume = {57}, year = {2016}, } @inproceedings{11835, abstract = {During the last 10 years it has become popular to study dynamic graph problems in a emergency planning or sensitivity setting: Instead of considering the general fully dynamic problem, we only have to process a single batch update of size d; after the update we have to answer queries. In this paper, we consider the dynamic subgraph connectivity problem with sensitivity d: We are given a graph of which some vertices are activated and some are deactivated. After that we get a single update in which the states of up to $d$ vertices are changed. Then we get a sequence of connectivity queries in the subgraph of activated vertices. We present the first fully dynamic algorithm for this problem which has an update and query time only slightly worse than the best decremental algorithm. In addition, we present the first incremental algorithm which is tight with respect to the best known conditional lower bound; moreover, the algorithm is simple and we believe it is implementable and efficient in practice.}, author = {Henzinger, Monika H and Neumann, Stefan}, booktitle = {24th Annual European Symposium on Algorithms}, isbn = {978-3-95977-015-6}, issn = {1868-8969}, location = {Aarhus, Denmark}, publisher = {Schloss Dagstuhl - Leibniz-Zentrum für Informatik}, title = {{Incremental and fully dynamic subgraph connectivity for emergency planning}}, doi = {10.4230/LIPICS.ESA.2016.48}, volume = {57}, year = {2016}, } @inproceedings{11836, abstract = {Given a graph where vertices are partitioned into k terminals and non-terminals, the goal is to compress the graph (i.e., reduce the number of non-terminals) using minor operations while preserving terminal distances approximately. The distortion of a compressed graph is the maximum multiplicative blow-up of distances between all pairs of terminals. We study the trade-off between the number of non-terminals and the distortion. This problem generalizes the Steiner Point Removal (SPR) problem, in which all non-terminals must be removed. We introduce a novel black-box reduction to convert any lower bound on distortion for the SPR problem into a super-linear lower bound on the number of non-terminals, with the same distortion, for our problem. This allows us to show that there exist graphs such that every minor with distortion less than 2 / 2.5 / 3 must have Omega(k^2) / Omega(k^{5/4}) / Omega(k^{6/5}) non-terminals, plus more trade-offs in between. The black-box reduction has an interesting consequence: if the tight lower bound on distortion for the SPR problem is super-constant, then allowing any O(k) non-terminals will not help improving the lower bound to a constant. We also build on the existing results on spanners, distance oracles and connected 0-extensions to show a number of upper bounds for general graphs, planar graphs, graphs that exclude a fixed minor and bounded treewidth graphs. Among others, we show that any graph admits a minor with O(log k) distortion and O(k^2) non-terminals, and any planar graph admits a minor with 1 + epsilon distortion and ~O((k/epsilon)^2) non-terminals.}, author = {Cheung, Yun Kuen and Goranci, Gramoz and Henzinger, Monika H}, booktitle = {43rd International Colloquium on Automata, Languages, and Programming}, isbn = {978-3-95977-013-2}, issn = {1868-8969}, location = {Rome, Italy}, publisher = {Schloss Dagstuhl - Leibniz-Zentrum für Informatik}, title = {{Graph minors for preserving terminal distances approximately - lower and upper bounds}}, doi = {10.4230/LIPICS.ICALP.2016.131}, volume = {55}, year = {2016}, } @article{1522, abstract = {We classify smooth Brunnian (i.e., unknotted on both components) embeddings (S2 × S1) ⊔ S3 → ℝ6. Any Brunnian embedding (S2 × S1) ⊔ S3 → ℝ6 is isotopic to an explicitly constructed embedding fk,m,n for some integers k, m, n such that m ≡ n (mod 2). Two embeddings fk,m,n and fk′ ,m′,n′ are isotopic if and only if k = k′, m ≡ m′ (mod 2k) and n ≡ n′ (mod 2k). We use Haefliger’s classification of embeddings S3 ⊔ S3 → ℝ6 in our proof. The relation between the embeddings (S2 × S1) ⊔ S3 → ℝ6 and S3 ⊔ S3 → ℝ6 is not trivial, however. For example, we show that there exist embeddings f: (S2 ×S1) ⊔ S3 → ℝ6 and g, g′ : S3 ⊔ S3 → ℝ6 such that the componentwise embedded connected sum f # g is isotopic to f # g′ but g is not isotopic to g′.}, author = {Avvakumov, Serhii}, issn = {1609-4514}, journal = {Moscow Mathematical Journal}, number = {1}, pages = {1 -- 25}, publisher = {Independent University of Moscow}, title = {{The classification of certain linked 3-manifolds in 6-space}}, doi = {10.17323/1609-4514-2016-16-1-1-25}, volume = {16}, year = {2016}, } @inproceedings{15245, abstract = {eXTP is a science mission designed to study the state of matter under extreme conditions of density, gravity and magnetism. Primary goals are the determination of the equation of state of matter at supra-nuclear density, the measurement of QED effects in highly magnetized star, and the study of accretion in the strong-field regime of gravity. Primary targets include isolated and binary neutron stars, strong magnetic field systems like magnetars, and stellar-mass and supermassive black holes. The mission carries a unique and unprecedented suite of state-of-the-art scientific instruments enabling for the first time ever the simultaneous spectral-timing-polarimetry studies of cosmic sources in the energy range from 0.5-30 keV (and beyond). Key elements of the payload are: the Spectroscopic Focusing Array (SFA) - a set of 11 X-ray optics for a total effective area of ∼0.9 m2 and 0.6 m2 at 2 keV and 6 keV respectively, equipped with Silicon Drift Detectors offering <180 eV spectral resolution; the Large Area Detector (LAD) - a deployable set of 640 Silicon Drift Detectors, for a total effective area of ∼3.4 m2, between 6 and 10 keV, and spectral resolution better than 250 eV; the Polarimetry Focusing Array (PFA) - a set of 2 X-ray telescope, for a total effective area of 250 cm2 at 2 keV, equipped with imaging gas pixel photoelectric polarimeters; the Wide Field Monitor (WFM) - a set of 3 coded mask wide field units, equipped with position-sensitive Silicon Drift Detectors, each covering a 90 degrees x 90 degrees field of view. The eXTP international consortium includes major institutions of the Chinese Academy of Sciences and Universities in China, as well as major institutions in several European countries and the United States. The predecessor of eXTP, the XTP mission concept, has been selected and funded as one of the so-called background missions in the Strategic Priority Space Science Program of the Chinese Academy of Sciences since 2011. The strong European participation has significantly enhanced the scientific capabilities of eXTP. The planned launch date of the mission is earlier than 2025.}, author = {Zhang, S. N. and Feroci, M. and Santangelo, A. and Dong, Y. W. and Feng, H. and Lu, F. J. and Nandra, K. and Wang, Z. S. and Zhang, S. and Bozzo, E. and Brandt, S. and De Rosa, A. and Gou, L. J. and Hernanz, M. and van der Klis, M. and Li, X. D. and Liu, Y. and Orleanski, P. and Pareschi, G. and Pohl, M. and Poutanen, J. and Qu, J. L. and Schanne, S. and Stella, L. and Uttley, P. and Watts, A. and Xu, R. X. and Yu, W. F. and in ’t Zand, J. J. M. and Zane, S. and Alvarez, L. and Amati, L. and Baldini, L. and Bambi, C. and Basso, S. and Bhattacharyya, S. and Bellazzini, R. and Belloni, T. and Bellutti, P. and Bianchi, S. and Brez, A. and Bursa, M. and Burwitz, V. and Budtz-Jørgensen, C. and Caiazzo, Ilaria and Campana, R. and Cao, X. L. and Casella, P. and Chen, C. Y. and Chen, L. and Chen, T. and Chen, Y. and Chen, Y. and Chen, Y. P. and Civitani, M. and Coti Zelati, F. and Cui, W. and Cui, W. W. and Dai, Z. G. and Del Monte, E. and de Martino, D. and Di Cosimo, S. and Diebold, S. and Dovciak, M. and Donnarumma, I. and Doroshenko, V. and Esposito, P. and Evangelista, Y. and Favre, Y. and Friedrich, P. and Fuschino, F. and Galvez, J. L. and Gao, Z. L. and Ge, M. Y. and Gevin, O. and Goetz, D. and Han, D. W. and Heyl, J. and Horak, J. and Hu, W. and Huang, F. and Huang, Q. S. and Hudec, R. and Huppenkothen, D. and Israel, G. L. and Ingram, A. and Karas, V. and Karelin, D. and Jenke, P. A. and Ji, L. and Korpela, S. and Kunneriath, D. and Labanti, C. and Li, G. and Li, X. and Li, Z. S. and Liang, E. W. and Limousin, O. and Lin, L. and Ling, Z. X. and Liu, H. B. and Liu, H. W. and Liu, Z. and Lu, B. and Lund, N. and Lai, D. and Luo, B. and Luo, T. and Ma, B. and Mahmoodifar, S. and Marisaldi, M. and Martindale, A. and Meidinger, N. and Men, Y. P. and Michalska, M. and Mignani, R. and Minuti, M. and Motta, S. and Muleri, F. and Neilsen, J. and Orlandini, M. and Pan, A. T. and Patruno, A. and Perinati, E. and Picciotto, A. and Piemonte, C. and Pinchera, M. and Rachevski, A. and Rapisarda, M. and Rea, N. and Rossi, E. M. R. and Rubini, A. and Sala, G. and Shu, X. W. and Sgro, C. and Shen, Z. X. and Soffitta, P. and Song, L. M. and Spandre, G. and Stratta, G. and Strohmayer, T. E. and Sun, L. and Svoboda, J. and Tagliaferri, G. and Tenzer, C. and Hong, T. and Taverna, R. and Torok, G. and Turolla, R. and Vacchi, S. and Wang, J. and Walton, D. and Wang, K. and Wang, J. F. and Wang, R. J. and Wang, Y. F. and Weng, S. S. and Wilms, J. and Winter, B. and Wu, X. and Wu, X. F. and Xiong, S. L. and Xu, Y. P. and Xue, Y. Q. and Yan, Z. and Yang, S. and Yang, X. and Yang, Y. J. and Yuan, F. and Yuan, W. M. and Yuan, Y. F. and Zampa, G. and Zampa, N. and Zdziarski, A. and Zhang, C. and Zhang, C. L. and Zhang, L. and Zhang, X. and Zhang, Z. and Zhang, W. D. and Zheng, S. J. and Zhou, P. and Zhou, X. L.}, booktitle = {Proceedings of the SPIE}, issn = {0277-786X}, publisher = {SPIE}, title = {{eXTP: Enhanced X-ray timing and polarization mission}}, doi = {10.1117/12.2232034}, volume = {9905}, year = {2016}, } @article{1212, abstract = {Plants adjust their growth according to gravity. Gravitropism involves gravity perception, signal transduction, and asymmetric growth response, with organ bending as a consequence [1]. Asymmetric growth results from the asymmetric distribution of the plant-specific signaling molecule auxin [2] that is generated by lateral transport, mediated in the hypocotyl predominantly by the auxin transporter PIN-FORMED3 (PIN3) [3–5]. Gravity stimulation polarizes PIN3 to the bottom sides of endodermal cells, correlating with increased auxin accumulation in adjacent tissues at the lower side of the stimulated organ, where auxin induces cell elongation and, hence, organ bending. A curvature response allows the hypocotyl to resume straight growth at a defined angle [6], implying that at some point auxin symmetry is restored to prevent overbending. Here, we present initial insights into cellular and molecular mechanisms that lead to the termination of the tropic response. We identified an auxin feedback on PIN3 polarization as underlying mechanism that restores symmetry of the PIN3-dependent auxin flow. Thus, two mechanistically distinct PIN3 polarization events redirect auxin fluxes at different time points of the gravity response: first, gravity-mediated redirection of PIN3-mediated auxin flow toward the lower hypocotyl side, where auxin gradually accumulates and promotes growth, and later PIN3 polarization to the opposite cell side, depleting this auxin maximum to end the bending. Accordingly, genetic or pharmacological interference with the late PIN3 polarization prevents termination of the response and leads to hypocotyl overbending. This observation reveals a role of auxin feedback on PIN polarity in the termination of the tropic response. © 2016 Elsevier Ltd}, author = {Rakusová, Hana and Abbas, Mohamad and Han, Huibin and Song, Siyuan and Robert, Hélène and Friml, Jirí}, journal = {Current Biology}, number = {22}, pages = {3026 -- 3032}, publisher = {Cell Press}, title = {{Termination of shoot gravitropic responses by auxin feedback on PIN3 polarity}}, doi = {10.1016/j.cub.2016.08.067}, volume = {26}, year = {2016}, } @article{1222, abstract = {We consider packings of congruent circles on a square flat torus, i.e., periodic (w.r.t. a square lattice) planar circle packings, with the maximal circle radius. This problem is interesting due to a practical reason—the problem of “super resolution of images.” We have found optimal arrangements for N=6, 7 and 8 circles. Surprisingly, for the case N=7 there are three different optimal arrangements. Our proof is based on a computer enumeration of toroidal irreducible contact graphs.}, author = {Musin, Oleg and Nikitenko, Anton}, journal = {Discrete & Computational Geometry}, number = {1}, pages = {1 -- 20}, publisher = {Springer}, title = {{Optimal packings of congruent circles on a square flat torus}}, doi = {10.1007/s00454-015-9742-6}, volume = {55}, year = {2016}, } @article{12615, abstract = {We apply the process-based, distributed TOPKAPI-ETH glacio-hydrological model to a glacierized catchment (19% glacierized) in the semiarid Andes of central Chile. The semiarid Andes provides vital freshwater resources to valleys in Chile and Argentina, but only few glacio-hydrological modelling studies have been conducted, and its dominant hydrological processes remain poorly understood. The catchment contains two debris-free glaciers reaching down to 3900 m asl (Bello and Yeso glaciers) and one debris-covered avalanche-fed glacier reaching to 3200 m asl (Piramide Glacier). Our main objective is to compare the mass balance and runoff contributions of both glacier types under current climatic conditions. We use a unique dataset of field measurements collected over two ablation seasons combined with the distributed TOPKAPI-ETH model that includes physically oriented parameterizations of snow and ice ablation, gravitational distribution of snow, snow albedo evolution and the ablation of debris-covered ice. Model outputs indicate that while the mass balance of Bello and Yeso glaciers is mostly explained by temperature gradients, the Piramide Glacier mass balance is governed by debris thickness and avalanches and has a clear non-linear profile with elevation as a result. Despite the thermal insulation effect of the debris cover, the mass balance and contribution to runoff from debris-free and debris-covered glaciers are similar in magnitude, mainly because of elevation differences. However, runoff contributions are distinct in time and seasonality with ice melt starting approximately four weeks earlier from the debris-covered glacier, what is of relevance for water resources management. At the catchment scale, snowmelt is the dominant contributor to runoff during both years. However, during the driest year of our simulations, ice melt contributes 42 ± 8% and 67 ± 6% of the annual and summer runoff, respectively. Sensitivity analyses show that runoff is most sensitive to temperature and precipitation gradients, melt factors and debris cover thickness. }, author = {Ayala, A. and Pellicciotti, Francesca and MacDonell, S. and McPhee, J. and Vivero, S. and Campos, C. and Egli, P.}, issn = {0885-6087}, journal = {Hydrological Processes}, keywords = {Water Science and Technology}, number = {22}, pages = {4036--4058}, publisher = {Wiley}, title = {{Modelling the hydrological response of debris-free and debris-covered glaciers to present climatic conditions in the semiarid Andes of central Chile}}, doi = {10.1002/hyp.10971}, volume = {30}, year = {2016}, } @article{12617, abstract = {This study presents volume and mass changes of seven (five partially debris-covered, two debris-free) glaciers in the upper Langtang catchment in Nepal. We use a digital elevation model (DEM) from 1974 stereo Hexagon satellite data and seven DEMs derived from 2006–2015 stereo or tri-stereo satellite imagery (e.g., SPOT6/7). The availability of multiple independent DEM differences allows the identification of a robust signal and narrowing down of the uncertainty about recent volume changes. The volume changes calculated over several multiyear periods between 2006 and 2015 consistently indicate that glacier thinning has accelerated with respect to the period 1974–2006. We calculate an ensemble-mean elevation change rate of –0.45 ± 0.18 m a−1 for 2006–2015, while for the period 1974–2006 we compute a rate of −0.24 ± 0.08 m a−1. However, the behavior of glaciers in the study area is heterogeneous, and the presence or absence of debris does not seem to be a good predictor for mass balance trends. Debris-covered tongues have nonlinear thinning profiles, and we show that recent accelerations in thinning correlate with the presence of supraglacial cliffs and lakes. At stagnating glacier areas near the glacier front, however, thinning rates decreased with time or remained constant. The April 2015 Nepal earthquake triggered large avalanches in the study catchment. Analysis of two post-earthquake DEMs revealed that the avalanche deposit volumes remaining 6 months after the earthquake are negligible in comparison to 2006–2015 elevation changes. However, the deposits compensate about 40 % the mass loss of debris-covered tongues of 1 average year.}, author = {Ragettli, Silvan and Bolch, Tobias and Pellicciotti, Francesca}, issn = {1994-0424}, journal = {The Cryosphere}, keywords = {Earth-Surface Processes, Water Science and Technology}, number = {5}, pages = {2075--2097}, publisher = {Copernicus Publications}, title = {{Heterogeneous glacier thinning patterns over the last 40 years in Langtang Himal, Nepal}}, doi = {10.5194/tc-10-2075-2016}, volume = {10}, year = {2016}, }