@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}, } @article{12625, abstract = {Debris-covered glaciers play an important role in the high-altitude water cycle in the Himalaya, yet their dynamics are poorly understood, partly because of the difficult fieldwork conditions. In this study we therefore deploy an unmanned aerial vehicle (UAV) three times (May 2013, October 2013 and May 2014) over the debris-covered Lirung Glacier in Nepal. The acquired data are processed into orthomosaics and elevation models by a Structure from Motion workflow, and seasonal surface velocity is derived using frequency cross-correlation. In order to obtain optimal surface velocity products, the effects of different input data and correlator configurations are evaluated, which reveals that the orthomosaic as input paired with moderate correlator settings provides the best results. The glacier has considerable spatial and seasonal differences in surface velocity, with maximum summer and winter velocities 6 and 2.5 m a-1, respectively, in the upper part of the tongue, while the lower part is nearly stagnant. It is hypothesized that the higher velocities during summer are caused by basal sliding due to increased lubrication of the bed. We conclude that UAVs have great potential to quantify seasonal and annual variations in flow and can help to further our understanding of debris-covered glaciers.}, author = {Kraaijenbrink, Philip and Meijer, Sander W. and Shea, Joseph M. and Pellicciotti, Francesca and De Jong, Steven M. and Immerzeel, Walter W.}, issn = {1727-5644}, journal = {Annals of Glaciology}, keywords = {Earth-Surface Processes}, number = {71}, pages = {103--113}, publisher = {International Glaciological Society}, title = {{Seasonal surface velocities of a Himalayan glacier derived by automated correlation of unmanned aerial vehicle imagery}}, doi = {10.3189/2016aog71a072}, volume = {57}, year = {2016}, } @article{1331, abstract = {Cytokinin is a phytohormone that is well known for its roles in numerous plant growth and developmental processes, yet it has also been linked to abiotic stress response in a less defined manner. Arabidopsis (Arabidopsis thaliana) Cytokinin Response Factor 6 (CRF6) is a cytokinin-responsive AP2/ERF-family transcription factor that, through the cytokinin signaling pathway, plays a key role in the inhibition of dark-induced senescence. CRF6 expression is also induced by oxidative stress, and here we show a novel function for CRF6 in relation to oxidative stress and identify downstream transcriptional targets of CRF6 that are repressed in response to oxidative stress. Analysis of transcriptomic changes in wild-type and crf6 mutant plants treated with H2O2 identified CRF6-dependent differentially expressed transcripts, many of which were repressed rather than induced. Moreover, many repressed genes also show decreased expression in 35S:CRF6 overexpressing plants. Together, these findings suggest that CRF6 functions largely as a transcriptional repressor. Interestingly, among the H2O2 repressed CRF6-dependent transcripts was a set of five genes associated with cytokinin processes: (signaling) ARR6, ARR9, ARR11, (biosynthesis) LOG7, and (transport) ABCG14. We have examined mutants of these cytokinin-associated target genes to reveal novel connections to oxidative stress. Further examination of CRF6-DNA interactions indicated that CRF6 may regulate its targets both directly and indirectly. Together, this shows that CRF6 functions during oxidative stress as a negative regulator to control this cytokinin-associated module of CRF6- dependent genes and establishes a novel connection between cytokinin and oxidative stress response.}, author = {Zwack, Paul and De Clercq, Inge and Howton, Timothy and Hallmark, H Tucker and Hurny, Andrej and Keshishian, Erika and Parish, Alyssa and Benková, Eva and Mukhtar, M Shahid and Van Breusegem, Frank and Rashotte, Aaron}, issn = {1532-2548}, journal = {Plant Physiology}, number = {2}, pages = {1249 -- 1258}, publisher = {American Society of Plant Biologists}, title = {{Cytokinin response factor 6 represses cytokinin-associated genes during oxidative stress}}, doi = {10.1104/pp.16.00415}, volume = {172}, 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{1616, abstract = {The hippocampus plays a key role in learning and memory. Previous studies suggested that the main types of principal neurons, dentate gyrus granule cells (GCs), CA3 pyramidal neurons, and CA1 pyramidal neurons, differ in their activity pattern, with sparse firing in GCs and more frequent firing in CA3 and CA1 pyramidal neurons. It has been assumed but never shown that such different activity may be caused by differential synaptic excitation. To test this hypothesis, we performed high-resolution whole-cell patch-clamp recordings in anesthetized rats in vivo. In contrast to previous in vitro data, both CA3 and CA1 pyramidal neurons fired action potentials spontaneously, with a frequency of ∼3–6 Hz, whereas GCs were silent. Furthermore, both CA3 and CA1 cells primarily fired in bursts. To determine the underlying mechanisms, we quantitatively assessed the frequency of spontaneous excitatory synaptic input, the passive membrane properties, and the active membrane characteristics. Surprisingly, GCs showed comparable synaptic excitation to CA3 and CA1 cells and the highest ratio of excitation versus hyperpolarizing inhibition. Thus, differential synaptic excitation is not responsible for differences in firing. Moreover, the three types of hippocampal neurons markedly differed in their passive properties. While GCs showed the most negative membrane potential, CA3 pyramidal neurons had the highest input resistance and the slowest membrane time constant. The three types of neurons also differed in the active membrane characteristics. GCs showed the highest action potential threshold, but displayed the largest gain of the input-output curves. In conclusion, our results reveal that differential firing of the three main types of hippocampal principal neurons in vivo is not primarily caused by differences in the characteristics of the synaptic input, but by the distinct properties of synaptic integration and input-output transformation.}, author = {Kowalski, Janina and Gan, Jian and Jonas, Peter M and Pernia-Andrade, Alejandro}, issn = {1098-1063}, journal = {Hippocampus}, number = {5}, pages = {668 -- 682}, publisher = {Wiley}, title = {{Intrinsic membrane properties determine hippocampal differential firing pattern in vivo in anesthetized rats}}, doi = {10.1002/hipo.22550}, volume = {26}, 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{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}, } @article{17618, abstract = {The largest observed supermassive black holes (SMBHs) have a mass of M_BH ~ 10^{10} M_sun, nearly independent of redshift, from the local (z~0) to the early (z>6) Universe. We suggest that the growth of SMBHs above a few 10^{10} M_sun is prevented by small-scale accretion physics, independent of the properties of their host galaxies or of cosmology. Growing more massive BHs requires a gas supply rate from galactic scales onto a nuclear region as high as >10^3 M_sun/yr. At such a high accretion rate, most of the gas converts to stars at large radii (~10-100 pc), well before reaching the BH. We adopt a simple model (Thompson et al. 2005) for a star-forming accretion disk, and find that the accretion rate in the sub-pc nuclear region is reduced to the smaller value of at most a few M_sun/yr. This prevents SMBHs from growing above ~10^{11} M_sun in the age of the Universe. Furthermore, once a SMBH reaches a sufficiently high mass, this rate falls below the critical value at which the accretion flow becomes advection dominated. Once this transition occurs, BH feeding can be suppressed by strong outflows and jets from hot gas near the BH. We find that the maximum SMBH mass, given by this transition, is between M_{BH,max} ~ (1-6) * 10^{10} M_sun, depending primarily on the efficiency of angular momentum transfer inside the galactic disk, and not on other properties of the host galaxy.}, author = {Inayoshi, Kohei and Haiman, Zoltán}, issn = {0004-637X}, journal = {The Astrophysical Journal}, number = {2}, publisher = {American Astronomical Society}, title = {{Is there a maximum mass for black holes in galactic nuclei?}}, doi = {10.3847/0004-637x/828/2/110}, volume = {828}, year = {2016}, } @article{17709, abstract = {We study very-high rate spherically symmetric accretion flows onto a massive black hole (BH; 10^2 < M_BH < 10^6 Msun) embedded in a dense gas cloud with a low abundance of metals, performing one-dimensional hydrodynamical simulations which include multi-frequency radiation transfer and non-equilibrium primordial chemistry. We find that rapid gas supply from the Bondi radius at a hyper-Eddington rate can occur without being impeded by radiation feedback when (n/10^5 cm^-3) > (M_BH/10^4Msun)^{-1}(T/10^4 K)^{3/2}, where n and T are the density and temperature of ambient gas outside of the Bondi radius. The resulting accretion rate in this regime is steady, and larger than 3000 times the Eddington rate. At lower Bondi rates, the accretion is episodic due to radiative feedback and the average rate is limited below the Eddington rate. For the hyper-Eddington case, the steady solution consists of two parts: a radiation-dominated central core, where photon trapping due to electron scattering is important, and an accreting envelope which follows a Bondi profile with T~8000 K. When the emergent luminosity is limited below the Eddington luminosity because of photon trapping, radiation from the central region does not affect the gas dynamics at larger scales. We apply our result to the rapid formation of massive BHs in protogalaxies with a virial temperature of T_vir> 10^4 K. Once a seed BH forms at the center of the galaxy, it can grow up to a maximum ~10^5 (T_vir/10^4 K) Msun via gas accretion independent of the initial BH mass. Finally, we discuss possible observational signatures of rapidly accreting BHs with/without allowance for dust. We suggest that these systems could explain Lya emitters without X-rays and luminous infrared sources with hot dust emission, respectively.}, author = {Inayoshi, Kohei and Haiman, Zoltán and Ostriker, Jeremiah P.}, issn = {0035-8711}, journal = {Monthly Notices of the Royal Astronomical Society}, number = {4}, pages = {3738--3755}, publisher = {Oxford University Press}, title = {{Hyper-Eddington accretion flows on to massive black holes}}, doi = {10.1093/mnras/stw836}, volume = {459}, year = {2016}, } @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}, } @article{11519, abstract = {Faint Lyα emitters become increasingly rarer toward the reionization epoch (z ∼ 6–7). However, observations from a very large (∼5 deg2) Lyα narrow-band survey at z = 6.6 show that this is not the case for the most luminous emitters, capable of ionizing their own local bubbles. Here we present follow-up observations of the two most luminous Lyα candidates in the COSMOS field: “MASOSA” and “CR7.” We used X-SHOOTER, SINFONI, and FORS2 on the Very Large Telescope, and DEIMOS on Keck, to confirm both candidates beyond any doubt. We find redshifts of z = 6.541 and z = 6.604 for “MASOSA” and “CR7,” respectively. MASOSA has a strong detection in Lyα with a line width of 386 ± 30 km s−1 (FWHM) and with very high EW0 (>200 Å), but undetected in the continuum, implying very low stellar mass and a likely young, metal-poor stellar population. “CR7,” with an observed Lyα luminosity of 1043.92±0.05 erg s−1 is the most luminous Lyα emitter ever found at z > 6 and is spatially extended (∼16 kpc). “CR7” reveals a narrow Lyα line with 266 ± 15 km s−1 FWHM, being detected in the near-infrared (NIR) (rest-frame UV; β = −2.3 ± 0.1) and in IRAC/Spitzer. We detect a narrow He II 1640 Å emission line (6σ, FWHM = 130 ± 30 km s−1 ) in CR7 which can explain the clear excess seen in the J-band photometry (EW0 ∼ 80 Å). We find no other emission lines from the UV to the NIR in our X-SHOOTER spectra (He II/O III] 1663 Å > 3 and He II/C III] 1908 Å > 2.5). We conclude that CR7 is best explained by a combination of a PopIII-like population, which dominates the rest-frame UV and the nebular emission, and a more normal stellar population, which presumably dominates the mass. Hubble Space Telescope/WFC3 observations show that the light is indeed spatially separated between a very blue component, coincident with Lyα and He II emission, and two red components (∼5 kpc away), which dominate the mass. Our findings are consistent with theoretical predictions of a PopIII wave, with PopIII star formation migrating away from the original sites of star formation.}, author = {Sobral, David and Matthee, Jorryt J and Darvish, Behnam and Schaerer, Daniel and Mobasher, Bahram and Röttgering, Huub and Santos, Sérgio and Hemmati, Shoubaneh}, issn = {1538-4357}, journal = {The Astrophysical Journal}, keywords = {Space and Planetary Science, Astronomy and Astrophysics, dark ages, reionization, first stars – early universe – galaxies: evolution}, number = {2}, pages = {139}, publisher = {IOP Publishing}, title = {{Evidence for PopIII-like stellar populations in the most luminous Lyα emitters at the epoch of reionisation: Spectroscopic confirmation}}, doi = {10.1088/0004-637X/808/2/139}, volume = {808}, year = {2015}, } @inproceedings{11837, abstract = {Online social networks allow the collection of large amounts of data about the influence between users connected by a friendship-like relationship. When distributing items among agents forming a social network, this information allows us to exploit network externalities that each agent receives from his neighbors that get the same item. In this paper we consider Friends-of-Friends (2-hop) network externalities, i.e., externalities that not only depend on the neighbors that get the same item but also on neighbors of neighbors. For these externalities we study a setting where multiple different items are assigned to unit-demand agents. Specifically, we study the problem of welfare maximization under different types of externality functions. Let n be the number of agents and m be the number of items. Our contributions are the following: (1) We show that welfare maximization is APX-hard; we show that even for step functions with 2-hop (and also with 1-hop) externalities it is NP-hard to approximate social welfare better than (1-1/e). (2) On the positive side we present (i) an O(sqrt n)-approximation algorithm for general concave externality functions, (ii) an O(\log m)-approximation algorithm for linear externality functions, and (iii) an (1-1/e)\frac{1}{6}-approximation algorithm for 2-hop step function externalities. We also improve the result from [6] for 1-hop step function externalities by giving a (1-1/e)/2-approximation algorithm.}, author = {Bhattacharya, Sayan and Dvorák, Wolfgang and Henzinger, Monika H and Starnberger, Martin}, booktitle = {32nd International Symposium on Theoretical Aspects of Computer Science}, isbn = {978-3-939897-78-1}, issn = {1868-8969}, location = {Garching, Germany}, pages = {90--102}, publisher = {Schloss Dagstuhl - Leibniz-Zentrum für Informatik}, title = {{Welfare maximization with friends-of-friends network externalities}}, doi = {10.4230/LIPICS.STACS.2015.90}, volume = {30}, year = {2015}, } @article{259, abstract = {The Hasse principle and weak approximation is established for non-singular cubic hypersurfaces X over the function field Fq(t), provided that char(Fq) > 3 and X has dimension at least 6.}, author = {Browning, Timothy D and Vishe, Pankaj}, issn = {1420-8970}, journal = {Geometric and Functional Analysis}, number = {3}, pages = {671 -- 732}, publisher = {Springer Nature}, title = {{Rational points on cubic hypersurfaces over F_q(t) }}, doi = {10.1007/s00039-015-0328-5}, volume = {25}, year = {2015}, }