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    Time- and frequency-resolved fluorescence with a single TCSPC detector via a Fourier-transform approach 

    Perri, Antonio; Gaida, John H.; Farina, Andrea; Preda, Fabrizio; Viola, Daniele; Ballottari, Matteo; Hauer, Jürgen; De Silvestri, Sandro; D’Andrea, Cosimo; Cerullo, Giulio; et al.
    Polli, Dario
    Optics Express 2018; 26(3): Art. 2270
    We introduce a broadband single-pixel spectro-temporal fluorescence detector, combining time-correlated single photon counting (TCSPC) with Fourier transform (FT) spectroscopy. A birefringent common-path interferometer (CPI) generates two time-delayed replicas of the sample's fluorescence. Via FT of their interference signal at the detector, we obtain a two-dimensional map of the fluorescence as a function of detection wavelength and emission time, with high temporal and spectral resolution. Our instrument is remarkably simple, as it only requires the addition of a CPI to a standard single-pixel TCSPC system, and it shows a readily adjustable spectral resolution with inherently broad bandwidth coverage.
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    Topology determines force distributions in one-dimensional random spring networks 

    Heidemann, Knut M.; Sageman-Furnas, Andrew O.; Sharma, Abhinav; Rehfeldt, Florian; Schmidt, Christoph F.; Wardetzky, Max
    Physical Review E 2018; 97(2): Art. 022306
    etworks of elastic fibers are ubiquitous in biological systems and often provide mechanical stability to cells and tissues. Fiber-reinforced materials are also common in technology. An important characteristic of such materials is their resistance to failure under load. Rupture occurs when fibers break under excessive force and when that failure propagates. Therefore, it is crucial to understand force distributions. Force distributions within such networks are typically highly inhomogeneous and are not well understood. Here we construct a simple one-dimensional model system with periodic boundary conditions by randomly placing linear springs on a circle. We consider ensembles of such networks that consist of N nodes and have an average degree of connectivity z but vary in topology. Using a graph-theoretical approach that accounts for the full topology of each network in the ensemble, we show that, surprisingly, the force distributions can be fully characterized in terms of the parameters (N,z). Despite the universal properties of such (N,z) ensembles, our analysis further reveals that a classical mean-field approach fails to capture force distributions correctly. We demonstrate that network topology is a crucial determinant of force distributions in elastic spring networks.
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    Combined Forward-Backward Asymmetry Measurements in Top-Antitop Quark Production at the Tevatron 

    Aaltonen, T.; Abazov, V. M.; Abbott, B.; Acharya, B. S.; Adams, M.; Adams, T.; Agnew, J. P.; Alexeev, G. D.; Alkhazov, G.; Alton, A.; et al.
    Amerio, S.Amidei, D.Anastassov, A.Annovi, A.Antos, J.Apollinari, G.Appel, J. A.Arisawa, T.Artikov, A.Asaadi, J.Ashmanskas, W.Askew, A.Atkins, S.Auerbach, B.Augsten, K.Aurisano, A.Aushev, V.Aushev, Y.Avila, C.Azfar, F.Badaud, F.Badgett, W.Bae, T.Bagby, L.Baldin, B.Bandurin, D. V.Banerjee, S.Barbaro-Galtieri, A.Barberis, E.Baringer, P.Barnes, V. E.Barnett, B. A.Barria, P.Bartlett, J. F.Bartos, P.Bassler, U.Bauce, M.Bazterra, V.Bean, A.Bedeschi, F.Begalli, M.Behari, S.Bellantoni, L.Bellettini, G.Bellinger, J.Benjamin, D.Beretvas, A.Beri, S. B.Bernardi, G.Bernhard, R.Bertram, I.Besançon, M.Beuselinck, R.Bhat, P. C.Bhatia, S.Bhatnagar, V.Bhatti, A.Bland, K. R.Blazey, G.Blessing, S.Bloom, K.Blumenfeld, B.Bocci, A.Bodek, A.Boehnlein, A.Boline, D.Boos, E. E.Borissov, G.Bortoletto, D.Borysova, M.Boudreau, J.Boveia, A.Brandt, A.Brandt, O.Brigliadori, L.Brochmann, M.Brock, R.Bromberg, C.Bross, A.Brown, D.Brucken, E.Bu, X. B.Budagov, J.Budd, H. S.Buehler, M.Buescher, V.Bunichev, V.Burdin, S.Burkett, K.Busetto, G.Bussey, P.Buszello, C. P.Butti, P.Buzatu, A.Calamba, A.Camacho-Pérez, E.Camarda, S.Campanelli, M.Canelli, F.Carls, B.Carlsmith, D.Carosi, R.Carrillo, S.Casal, B.Casarsa, M.Casey, B. C. K.Castilla-Valdez, H.Castro, A.Catastini, P.Caughron, S.Cauz, D.Cavaliere, V.Cerri, A.Cerrito, L.Chakrabarti, S.Chan, K. M.Chandra, A.Chapelain, A.Chapon, E.Chen, G.Chen, Y. C.Chertok, M.Chiarelli, G.Chlachidze, G.Cho, K.Cho, S. W.Choi, S.Chokheli, D.Choudhary, B.Cihangir, S.Claes, D.Clark, A.Clarke, C.Clutter, J.Convery, M. E.Conway, J.Cooke, M.Cooper, W. E.Corbo, M.Corcoran, M.Cordelli, M.Couderc, F.Cousinou, M.-C.Cox, C. A.Cox, D. J.Cremonesi, M.Cruz, D.Cuevas, J.Culbertson, R.Cuth, J.Cutts, D.Das, A.d'Ascenzo, N.Datta, M.Davies, G.de Barbaro, P.de Jong, S. J.De La Cruz-Burelo, E.Déliot, F.Demina, R.Demortier, L.Deninno, M.Denisov, D.Denisov, S. P.D'Errico, M.Desai, S.Deterre, C.DeVaughan, K.Devoto, F.Di Canto, A.Di Ruzza, B.Diehl, H. T.Diesburg, M.Ding, P. F.Dittmann, J. R.Dominguez, A.Donati, S.D'Onofrio, M.Dorigo, M.Driutti, A.Drutskoy, A.Dubey, A.Dudko, L. V.Duperrin, A.Dutt, S.Eads, M.Ebina, K.Edgar, R.Edmunds, D.Elagin, A.Ellison, J.Elvira, V. D.Enari, Y.Erbacher, R.Errede, S.Esham, B.Evans, H.Evdokimov, A.Evdokimov, V. N.Farrington, S.Fauré, A.Feng, L.Ferbel, T.Fernández Ramos, J. P.Fiedler, F.Field, R.Filthaut, F.Fisher, W.Fisk, H. E.Flanagan, G.Forrest, R.Fortner, M.Fox, H.Franc, J.Franklin, M.Freeman, J. C.Frisch, H.Fuess, S.Funakoshi, Y.Galloni, C.Garbincius, P. H.Garcia-Bellido, A.García-González, J. A.Garfinkel, A. F.Garosi, P.Gavrilov, V.Geng, W.Gerber, C. E.Gerberich, H.Gerchtein, E.Gershtein, Y.Giagu, S.Giakoumopoulou, V.Gibson, K.Ginsburg, C. M.Ginther, G.Giokaris, N.Giromini, P.Glagolev, V.Glenzinski, D.Gogota, O.Gold, M.Goldin, D.Golossanov, A.Golovanov, G.Gomez, G.Gomez-Ceballos, G.Goncharov, M.González López, O.Gorelov, I.Goshaw, A. T.Goulianos, K.Gramellini, E.Grannis, P. D.Greder, S.Greenlee, H.Grenier, G.Gris, Ph.Grivaz, J.-F.Grohsjean, A.Grosso-Pilcher, C.Grünendahl, S.Grünewald, M. W.Guillemin, T.Guimaraes da Costa, J.Gutierrez, G.Gutierrez, P.Hahn, S. R.Haley, J.Han, J. Y.Han, L.Happacher, F.Hara, K.Harder, K.Hare, M.Harel, A.Harr, R. F.Harrington-Taber, T.Hatakeyama, K.Hauptman, J. M.Hays, C.Hays, J.Head, T.Hebbeker, T.Hedin, D.Hegab, H.Heinrich, J.Heinson, A. P.Heintz, U.Hensel, C.Heredia-De La Cruz, I.Herndon, M.Herner, K.Hesketh, G.Hildreth, M. D.Hirosky, R.Hoang, T.Hobbs, J. D.Hocker, A.Hoeneisen, B.Hogan, J.Hohlfeld, M.Holzbauer, J. L.Hong, Z.Hopkins, W.Hou, SHowley, I.Hubacek, Z.Hughes, R. E.Husemann, U.Hussein, M.Huston, J.Hynek, V.Iashvili, I.Ilchenko, Y.Illingworth, R.Introzzi, G.Iori, M.Ito, A. S.Ivanov, A.Jabeen, S.Jaffré, M.James, E.Jang, D.Jayasinghe, A.Jayatilaka, B.Jeon, E. J.Jeong, M. S.Jesik, R.Jiang, P.Jindariani, S.Johns, K.Johnson, E.Johnson, M.Jonckheere, A.Jones, M.Jonsson, P.Joo, K. K.Joshi, J.Jun, S. Y.Jung, A. W.Junk, T. R.Juste, A.Kajfasz, E.Kambeitz, M.Kamon, T.Karchin, P. E.Karmanov, D.Kasmi, A.Kato, Y.Katsanos, I.Kaur, M.Kehoe, R.Kermiche, S.Ketchum, W.Keung, J.Khalatyan, N.Khanov, A.Kharchilava, A.Kharzheev, Y. N.Kilminster, B.Kim, D. H.Kim, H. S.Kim, J. E.Kim, M. J.Kim, S. H.Kim, S. B.Kim, Y. J.Kim, Y. K.Kimura, N.Kirby, M.Kiselevich, I.Kohli, J. M.Kondo, K.Kong, D. J.Konigsberg, J.Kotwal, A. V.Kozelov, A. V.Kraus, J.Kreps, M.Kroll, J.Kruse, M.Kuhr, T.Kumar, A.Kupco, A.Kurata, M.Kurča, T.Kuzmin, V. A.Laasanen, A. T.Lammel, S.Lammers, S.Lancaster, M.Lannon, K.Latino, G.Lebrun, P.Lee, H. S.Lee, H. S.Lee, J. S.Lee, S. W.Lee, W. M.Lei, X.Lellouch, J.Leo, S.Leone, S.Lewis, J. D.Li, D.Li, H.Li, L.Li, Q. Z.Lim, J. K.Limosani, A.Lincoln, D.Linnemann, J.Lipaev, V. V.Lipeles, E.Lipton, R.Lister, A.Liu, H.Liu, Q.Liu, T.Liu, Y.Lobodenko, A.Lockwitz, S.Loginov, A.Lokajicek, M.Lopes de Sa, R.Lucchesi, D.Lucà, A.Lueck, J.Lujan, P.Lukens, P.Luna-Garcia, R.Lungu, G.Lyon, A. L.Lys, J.Lysak, R.Maciel, A. K. A.Madar, R.Madrak, R.Maestro, P.Magaña-Villalba, R.Malik, S.Malik, S.Malyshev, V. L.Manca, G.Manousakis-Katsikakis, A.Mansour, J.Marchese, L.Margaroli, F.Marino, P.Martínez-Ortega, J.Matera, K.Mattson, M. E.Mazzacane, A.Mazzanti, P.McCarthy, R.McGivern, C. L.McNulty, R.Mehta, A.Mehtala, P.Meijer, M. M.Melnitchouk, A.Menezes, D.Mercadante, P. G.Merkin, M.Mesropian, C.Meyer, A.Meyer, J.Miao, T.Miconi, F.Mietlicki, D.Mitra, A.Miyake, H.Moed, S.Moggi, N.Mondal, N. K.Moon, C. S.Moore, R.Morello, M. J.Mukherjee, A.Mulhearn, M.Muller, Th.Murat, P.Mussini, M.Nachtman, J.Nagai, Y.Naganoma, J.Nagy, E.Nakano, I.Napier, A.Narain, M.Nayyar, R.Neal, H. A.Negret, J. P.Nett, J.Neustroev, P.Nguyen, H. T.Nigmanov, T.Nodulman, L.Noh, S. Y.Norniella, O.Nunnemann, T.Oakes, L.Oh, S. H.Oh, Y. D.Okusawa, T.Orava, R.Orduna, J.Ortolan, L.Osman, N.Pagliarone, C.Pal, A.Palencia, E.Palni, P.Papadimitriou, V.Parashar, N.Parihar, V.Park, S. K.Parker, W.Partridge, R.Parua, N.Patwa, A.Pauletta, G.Paulini, M.Paus, C.Penning, B.Perfilov, M.Peters, Y.Petridis, K.Petrillo, G.Pétroff, P.Phillips, T. J.Piacentino, G.Pianori, E.Pilot, J.Pitts, K.Plager, C.Pleier, M.-A.Podstavkov, V. M.Pondrom, L.Popov, A. V.Poprocki, S.Potamianos, K.Pranko, A.Prewitt, M.Price, D.Prokopenko, N.Prokoshin, F.Ptohos, F.Punzi, G.Qian, J.Quadt, A.Quinn, B.Ratoff, P. N.Razumov, I.Redondo Fernández, I.Renton, P.Rescigno, M.Rimondi, F.Ripp-Baudot, I.Ristori, L.Rizatdinova, F.Robson, A.Rodriguez, T.Rolli, S.Rominsky, M.Ronzani, M.Roser, R.Rosner, J. L.Ross, A.Royon, C.Rubinov, P.Ruchti, R.Ruffini, F.Ruiz, A.Russ, J.Rusu, V.Sajot, G.Sakumoto, W. K.Sakurai, Y.Sánchez-Hernández, A.Sanders, M. P.Santi, L.Santos, A. S.Sato, K.Savage, G.Saveliev, V.Savitskyi, M.Savoy-Navarro, A.Sawyer, L.Scanlon, T.Schamberger, R. D.Scheglov, Y.Schellman, H.Schlabach, P.Schmidt, E. E.Schott, M.Schwanenberger, C.Schwarz, T.Schwienhorst, R.Scodellaro, L.Scuri, F.Seidel, S.Seiya, Y.Sekaric, J.Semenov, A.Severini, HSforza, F.Shabalina, E.Shalhout, S. Z.Shary, V.Shaw, S.Shchukin, A. A.Shears, T.Shepard, P. F.Shimojima, M.Shkola, O.Shochet, M.Shreyber-Tecker, I.Simak, V.Simonenko, A.Skubic, P.Slattery, P.Sliwa, K.Smith, J. R.Snider, .F D.Snow, G. R.Snow, J.Snyder, S.Söldner-Rembold, S.Song, H.Sonnenschein, L.Sorin, V.Soustruznik, K.St Denis, R.Stancari, M.Stark, J.Stefaniuk, N.Stentz, D.Stoyanova, D. A.Strauss, M.Strologas, J.Sudo, Y.Sukhanov, A.Suslov, I.Suter, L.Svoisky, P.Takemasa, K.Takeuchi, Y.Tang, J.Tecchio, M.Teng, P. K.Thom, J.Thomson, E.Thukral, V.Titov, M.Toback, D.Tokar, S.Tokmenin, V. V.Tollefson, K.Tomura, T.Tonelli, D.Torre, S.Torretta, D.Totaro, P.Trovato, M.Tsai, Y.-T.Tsybychev, D.Tuchming, B.Tully, C.Ukegawa, F.Uozumi, S.Uvarov, L.Uvarov, S.Uzunyan, S.Van Kooten, R.van Leeuwen, W. M.Varelas, N.Varnes, E. W.Vasilyev, I. A.Vázquez, F.Velev, G.Vellidis, C.Verkheev, A. Y.Vernieri, C.Vertogradov, L. S.Verzocchi, M.Vesterinen, M.Vidal, M.Vilanova, D.Vilar, R.Vizán, J.Vogel, M.Vokac, P.Volpi, G.Wagner, P.Wahl, H. D.Wallny, R.Wang, M. H. L. S.Wang, S. M.Warchol, J.Waters, D.Watts, G.Wayne, M.Weichert, J.Welty-Rieger, L.Wester, W. C.Whiteson, D.Wicklund, A. B.Wilbur, S.Williams, H. H.Williams, M. R. J.Wilson, G. W.Wilson, J. S.Wilson, P.Winer, B. L.Wittich, P.Wobisch, M.Wolbers, S.Wolfmeister, H.Wood, D. R.Wright, T.Wu, X.Wu, Z.Wyatt, T. R.Xie, Y.Yamada, R.Yamamoto, K.Yamato, D.Yang, S.Yang, T.Yang, U. K.Yang, Y. C.Yao, W.-M.Yasuda, T.Yatsunenko, Y. A.Ye, W.Ye, Z.Yeh, G. P.Yi, K.Yin, H.Yip, K.Yoh, J.Yorita, K.Yoshida, T.Youn, S. W.Yu, G. B.Yu, I.Yu, J. M.Zanetti, A. M.Zeng, Y.Zennamo, J.Zhao, T. G.Zhou, B.Zhou, C.Zhu, J.Zielinski, M.Zieminska, D.Zivkovic, L.Zucchelli, S.
    Physical Review Retters 2018; 120(4): Art. 042001
    The CDF and D0 experiments at the Fermilab Tevatron have measured the asymmetry between yields of forward- and backward-produced top and antitop quarks based on their rapidity difference and the asymmetry between their decay leptons. These measurements use the full data sets collected in proton-antiproton collisions at a center-of-mass energy of sqrt[s]=1.96  TeV. We report the results of combinations of the inclusive asymmetries and their differential dependencies on relevant kinematic quantities. The combined inclusive asymmetry is A_{FB}^{tt[over ¯]}=0.128±0.025. The combined inclusive and differential asymmetries are consistent with recent standard model predictions.
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    Photodissociation of aligned CH3I and C6H3F2I molecules probed with time-resolved Coulomb explosion imaging by site-selective extreme ultraviolet ionization. 

    Amini, Kasra; Savelyev, Evgeny; Brauße, Felix; Berrah, Nora; Bomme, Cédric; Brouard, Mark; Burt, Michael; Christensen, Lauge; Düsterer, Stefan; Erk, Benjamin; et al.
    Höppner, HaukeKierspel, ThomasKrecinic, FarukLauer, AlexandraLee, Jason W. L.Müller, MariaMüller, ErlandMullins, TerenceRedlin, HaraldSchirmel, NoraThøgersen, JanTechert, SimoneToleikis, SvenTreusch, RolfTrippel, SebastianUlmer, AnatoliVallance, ClaireWiese, JossJohnsson, PerKüpper, JochenRudenko, ArtemRouzée, ArnaudStapelfeldt, HenrikRolles, DanielBoll, Rebecca
    Structural Dynamics 2018; 5(1): Art. 014301
    We explore time-resolved Coulomb explosion induced by intense, extreme ultraviolet (XUV) femtosecond pulses from a free-electron laser as a method to image photo-induced molecular dynamics in two molecules, iodomethane and 2,6-difluoroiodobenzene. At an excitation wavelength of 267 nm, the dominant reaction pathway in both molecules is neutral dissociation via cleavage of the carbon-iodine bond. This allows investigating the influence of the molecular environment on the absorption of an intense, femtosecond XUV pulse and the subsequent Coulomb explosion process. We find that the XUV probe pulse induces local inner-shell ionization of atomic iodine in dissociating iodomethane, in contrast to non-selective ionization of all photofragments in difluoroiodobenzene. The results reveal evidence of electron transfer from methyl and phenyl moieties to a multiply charged iodine ion. In addition, indications for ultrafast charge rearrangement on the phenyl radical are found, suggesting that time-resolved Coulomb explosion imaging is sensitive to the localization of charge in extended molecules.
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    Constraining scalar resonances with top-quark pair production at the LHC 

    Franzosi, Diogo Buarque; Fabbri, Federica; Schumann, Steffen
    Journal of High Energy Physics 2018; 2018(3): Art. 22
    Constraints on models which predict resonant top-quark pair production at the LHC are provided via a reinterpretation of the Standard Model (SM) particle level measurement of the top-anti-top invariant mass distribution, m(t t). We make use of stateof- the-art Monte Carlo event simulation to perform a direct comparison with measurements of m(t t) in the semi-leptonic channels, considering both the boosted and the resolved regime of the hadronic top decays. A simpli ed model to describe various scalar resonances decaying into top-quarks is considered, including CP-even and CP-odd, color-singlet and color-octet states, and the excluded regions in the respective parameter spaces are provided.
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    An ensemble framework for time delay synchronization 

    Pinheiro, Flavia R.; van Leeuwen, Peter Jan; Parlitz, Ulrich
    Quarterly Journal of the Royal Meteorological Society 2018; 144(711) p.305-316
    Synchronization based state estimation tries to synchronize a model with the true evolution of a system via the observations. In practice, an extra term is added to the model equations which hampers growth of instabilities transversal to the synchronization manifold. Therefore, there is a very close connection between synchronization and data assimilation. Recently, synchronization with time-delayed observations has been proposed, in which observations at future times are used to help synchronize a system that does not synchronize using only present observations, with remarkable successes. Unfortunately, these schemes are limited to small-dimensional problems. In this article, we lift that restriction by proposing an ensemble-based synchronization scheme. Tests were performed using the Lorenz’96 model for 20-, 100- and 1000-dimension systems. Results show global synchronization errors stabilizing at values of at least an order of magnitude lower than the observation errors, suggesting that the scheme is a promising tool to steer model states to the truth. While this framework is not a complete data assimilation method, we develop this methodology as a potential choice for a proposal density in a more comprehensive data assimilation method, like a fully nonlinear particle filter.
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    Partially composite Higgs models: phenomenology and RG analysis 

    Alanne, Tommi; Buarque Franzosi, Diogo; Frandsen, Mads T.; Kristensen, Mette L. A.; Meroni, Aurora; Rosenlyst, Martin
    Journal of High Energy Physics 2018; 2018(1): Art. 51
    Abstract: We study the phenomenology of partially composite-Higgs models where electroweak symmetry breaking is dynamically induced, and the Higgs is a mixture of a composite and an elementary state. The models considered have explicit realizations in terms of gauge-Yukawa theories with new strongly interacting fermions coupled to elementary scalars and allow for a very SM-like Higgs state. We study constraints on their parameter spaces from vacuum stability and perturbativity as well as from LHC results and nd that requiring vacuum stability up to the compositeness scale already imposes relevant constraints. A small part of parameter space around the classically conformal limit is stable up to the Planck scale. This is however already strongly disfavored by LHC results. In different limits, the models realize both (partially) composite-Higgs and (bosonic) technicolor models and a dynamical extension of the fundamental Goldstone-Higgs model. Therefore, they provide a general framework for exploring the phenomenology of composite dynamics.
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    Microfluidic device for chemical and mechanical manipulation of suspended cells 

    Rezvani, Samaneh; Shi, Nan; Squires, Todd M.; Schmidt, Christoph F.
    Journal of Physics D: Applied Physics 2018; 51(4)
    Microfluidic devices have proven to be useful and versatile for cell studies. We here report on a method to adapt microfluidic stickers made from UV-curable optical adhesive with inserted permeable hydrogel membrane micro-windows for mechanical studies of suspended cells. The windows were fabricated by optical projection lithography using scanning confocal microscopy. The device allows us to rapidly exchange embedding medium while observing and probing the cells. We characterize the device and demonstrate the function by exposing cultured fibroblasts to varying osmotic conditions. Cells can be shrunk reversibly under osmotic compression.
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    Neon ion beam induced pattern formation on amorphous carbon surfaces 

    Bobes, Omar; Hofsäss, Hans; Zhang, Kun
    AIP Advances 2018; 8(2): Art. 025205
    We investigate the ripple pattern formation on amorphous carbon surfaces at room temperature during low energy Ne ion irradiation as a function of the ion incidence angle. Monte Carlo simulations of the curvature coefficients applied to the Bradley-Harper and Cater-Vishnyakov models, including the recent extensions by Harrison-Bradley and Hofsäss predict that pattern formation on amorphous carbon thin films should be possible for low energy Ne ions from 250 eV up to 1500 eV. Moreover, simulations are able to explain the absence of pattern formation in certain cases. Our experimental results are compared with prediction using current linear theoretical models and applying the crater function formalism, as well as Monte Carlo simulations to calculate curvature coefficients using the SDTrimSP program. Calculations indicate that no patterns should be generated up to 45° incidence angle if the dynamic behavior of the thickness of the ion irradiated layer introduced by Hofsäss is taken into account, while pattern formation most pronounced from 50° for ion energy between 250 eV and 1500 eV, which are in good agreement with our experimental data.
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    Rhombic organization of microvilli domains found in a cell model of the human intestine 

    Franz, Jonas; Grünebaum, Jonas; Schäfer, Marcus; Mulac, Dennis; Rehfeldt, Florian; Langer, Klaus; Kramer, Armin; Riethmüller, Christoph
    PlOS ONE 2018; 13(1): Art. e0189970
    Symmetry is rarely found on cellular surfaces. An exception is the brush border of microvilli, which are essential for the proper function of transport epithelia. In a healthy intestine, they appear densely packed as a 2D-hexagonal lattice. For in vitro testing of intestinal transport the cell line Caco-2 has been established. As reported by electron microscopy, their microvilli arrange primarily in clusters developing secondly into a 2D-hexagonal lattice. Here, atomic force microscopy (AFM) was employed under aqueous buffer conditions on Caco-2 cells, which were cultivated on permeable filter membranes for optimum differentiation. For analysis, the exact position of each microvillus was detected by computer vision; subsequent Fourier transformation yielded the type of 2D-lattice. It was confirmed, that Caco-2 cells can build a hexagonal lattice of microvilli and form clusters. Moreover, a second type of arrangement was discovered, namely a rhombic lattice, which appeared at sub-maximal densities of microvilli with (29 ± 4) microvilli / μm2. Altogether, the findings indicate the existence of a yet undescribed pattern in cellular organization.
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    The MUSE Hubble Ultra Deep Field Survey. IV. Global properties of CIII] emitters 

    Maseda, Michael V.; Brinchmann, Jarle; Franx, Marijn; Bacon, Roland; Bouwens, Rychard J.; Schmidt, Kasper B.; Boogaard, Leindert A.; Contini, Thierry; Feltre, Anna; Inami, Hanae; et al.
    Kollatschny, WolframMarino, Raffaella A.Richard, JohanVerhamme, AnneWisotzki, Lutz
    Astronomy & Astrophysics 2017; 608 p.1-16: Art. A4
    The CIII] 1907, 1909 emission doublet has been proposed as an alternative to Lyman- in redshift confirmations of galaxies at z & 6 since it is not attenuated by the largely neutral intergalactic medium at these redshifts and is believed to be strong in the young, vigorously star-forming galaxies present at these early cosmic times. We present a statistical sample of 17 CIII]-emitting galaxies beyond z 1:5 using 30 h deep VLT/MUSE integral field spectroscopy covering 2 square arcminutes in the Hubble Deep Field South (HDFS) and Ultra Deep Field (UDF), achieving C III] sensitivities of 2 10􀀀17 erg s􀀀1 cm􀀀2 in the HDFS and 7 10􀀀18 erg s􀀀1 cm􀀀2 in the UDF. The rest-frame equivalent widths range from 2 to 19 Å. These 17 galaxies represent 3% of the total sample of galaxies found between 1:5 . z . 4. They also show elevated star formation rates, lower dust attenuation, and younger mass-weighted ages than the general population of galaxies at the same redshifts. Combined with deep slitless grism spectroscopy from the HST/WFC3 in the UDF, we can tie the rest-frame ultraviolet C III] emission to rest-frame optical emission lines, namely [O III] 5007, finding a strong correlation between the two. Down to the flux limits that we observe ( 1 10􀀀18 erg s􀀀1 cm􀀀2 with the grism data in the UDF), all objects with a rest-frame [O III] 4959, 5007 equivalent width in excess of 250 Å, the so-called extreme emission line galaxies, have detections of CIII] in our MUSE data. More detailed studies of the C III]-emitting population at these intermediate redshifts will be crucial to understand the physical conditions in galaxies at early cosmic times and to determine the utility of C III] as a redshift tracer.
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    The MUSE Hubble Ultra Deep Field Survey. II. Spectroscopic redshifts and comparisons to color selections of high-redshift galaxies 

    Inami, H.; Bacon, R.; Brinchmann, J.; Richard, J.; Contini, T.; Conseil, S.; Hamer, S.; Akhlaghi, M.; Bouché, N.; Clément, B.; et al.
    Desprez, G.Drake, A. B.Hashimoto, T.Leclercq, F.Maseda, M.Michel-Dansac, L.Paalvast, M.Tresse, L.Ventou, E.Kollatschny, W.Boogaard, L. A.Finley, H.Marino, R. A.Schaye, J.Wisotzki, L.
    Astronomy & Astrophysics 2017; 608 p.1-26: Art. A2
    We have conducted a two-layered spectroscopic survey (10 10 ultra deep and 30 30 deep regions) in the Hubble Ultra Deep Field (HUDF) with the Multi Unit Spectroscopic Explorer (MUSE). The combination of a large field of view, high sensitivity, and wide wavelength coverage provides an order of magnitude improvement in spectroscopically confirmed redshifts in the HUDF; i.e., 1206 secure spectroscopic redshifts for Hubble Space Telescope (HST) continuum selected objects, which corresponds to 15% of the total (7904). The redshift distribution extends well beyond z > 3 and to HST/F775W magnitudes as faint as 30 mag (AB, 1 ). In addition, 132 secure redshifts were obtained for sources with no HST counterparts that were discovered in the MUSE data cubes by a blind search for emission-line features. In total, we present 1338 high quality redshifts, which is a factor of eight increase compared with the previously known spectroscopic redshifts in the same field.We assessed redshifts mainly with the spectral features [O ii] at z < 1:5 (473 objects) and Ly at 2:9 < z < 6:7 (692 objects). With respect to F775W magnitude, a 50% completeness is reached at 26:5 mag for ultra deep and 25:5 mag for deep fields, and the completeness remains &20% up to 28–29 mag and 27 mag, respectively.We used the determined redshifts to test continuum color selection (dropout) diagrams of high-z galaxies. The selection condition for F336W dropouts successfully captures 80% of the targeted z 2:7 galaxies. However, for higher redshift selections (F435W, F606W, and F775W dropouts), the success rates decrease to 20–40%. We empirically redefine the selection boundaries to make an attempt to improve them to 60%. The revised boundaries allow bluer colors that capture Ly emitters with high Ly equivalent widths falling in the broadbands used for the color-color selection. Along with this paper, we release the redshift and line flux catalog.
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    The MUSE Hubble Ultra Deep Field Survey. III. Testing photometric redshifts to 30th magnitude 

    Brinchmann, J.; Inami, H.; Bacon, R.; Contini, T.; Maseda, M.; Chevallard, J.; Bouché, N.; Boogaard, L.; Carollo, M.; Charlot, S.; et al.
    Kollatschny, W.Marino, R. A.Pello, R.Richard, J.Schaye, J.Verhamme, A.Wisotzki, L.
    Astronomy & Astrophysics 2017; 608 p.1-23: Art. A3
    We tested the performance of photometric redshifts for galaxies in the Hubble Ultra Deep field down to 30th magnitude. We compared photometric redshift estimates from three spectral fitting codes from the literature (EAZY, BPZ and BEAGLE) to high quality redshifts for 1227 galaxies from the MUSE integral field spectrograph. All these codes can return photometric redshifts with bias j(zMUSE 􀀀 pz)=(1 + zMUSE)j < 0:05 down to F775W = 30 and spectroscopic incompleteness is unlikely to strongly modify this statement. We have, however, identified clear systematic biases in the determination of photometric redshifts: in the 0:4 < z < 1:5 range, photometric redshifts are systematically biased low by as much as (zMUSE 􀀀 pz)=(1 + zMUSE) = 􀀀0:04 in the median, and at z > 3 they are systematically biased high by up to (zMUSE 􀀀 pz)=(1 + zMUSE) = 0:05, an o set that can in part be explained by adjusting the amount of intergalactic absorption applied. In agreement with previous studies we find little di erence in the performance of the di erent codes, but in contrast to those we find that adding extensive ground-based and IRAC photometry actually can worsen photo-z performance for faint galaxies.We find an outlier fraction, defined through j(zMUSE 􀀀 pz)=(1 + zMUSE)j > 0:15, of 8% for BPZ and 10% for EAZY and BEAGLE, and show explicitly that this is a strong function of magnitude. While this outlier fraction is high relative to numbers presented in the literature for brighter galaxies, they are very comparable to literature results when the depth of the data is taken into account. Finally, we demonstrate that while a redshift might be of high confidence, the association of a spectrum to the photometric object can be very uncertain and lead to a contamination of a few percent in spectroscopic training samples that do not show up as catastrophic outliers, a problem that must be tackled in order to have su ciently accurate photometric redshifts for future cosmological surveys.
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    The MUSE Hubble Ultra Deep Field Survey. I. Survey description, data reduction, and source detection 

    Bacon, Roland; Conseil, Simon; Mary, David; Brinchmann, Jarle; Shepherd, Martin; Akhlaghi, Mohammad; Weilbacher, Peter M.; Piqueras, Laure; Wisotzki, Lutz; Lagattuta, David; et al.
    Epinat, BenoitGuerou, AdrienInami, HanaeCantalupo, SebastianoCourbot, Jean BaptisteContini, ThierryRichard, JohanMaseda, MichaelBouwens, RychardBouché, NicolasKollatschny, WolframSchaye, JoopMarino, Raffaella AnnaPello, RoserHerenz, ChristianGuiderdoni, BrunoCarollo, Marcella
    Astronomy & Astrophysics 2017; 608 p.1-20: Art. A1
    We present the MUSE Hubble Ultra Deep Survey, a mosaic of nine MUSE fields covering 90% of the entire HUDF region with a 10-h deep exposure time, plus a deeper 31-h exposure in a single 1.15 arcmin2 field. The improved observing strategy and advanced data reduction results in datacubes with sub-arcsecond spatial resolution (00:065 at 7000 Å) and accurate astrometry (00:007 rms). We compare the broadband photometric properties of the datacubes to HST photometry, finding a good agreement in zeropoint up to mAB = 28 but with an increasing scatter for faint objects. We have investigated the noise properties and developed an empirical way to account for the impact of the correlation introduced by the 3D drizzle interpolation. The achieved 3 emission line detection limit for a point source is 1:5 and 3:1 10􀀀19 erg s􀀀1 cm􀀀2 for the single ultra-deep datacube and the mosaic, respectively. We extracted 6288 sources using an optimal extraction scheme that takes the published HST source locations as prior. In parallel, we performed a blind search of emission line galaxies using an original method based on advanced test statistics and filter matching. The blind search results in 1251 emission line galaxy candidates in the mosaic and 306 in the ultradeep datacube, including 72 sources without HST counterparts (mAB > 31). In addition 88 sources missed in the HST catalog but with clear HST counterparts were identified. This data set is the deepest spectroscopic survey ever performed. In just over 100 h of integration time, it provides nearly an order of magnitude more spectroscopic redshifts compared to the data that has been accumulated on the UDF over the past decade. The depth and high quality of these datacubes enables new and detailed studies of the physical properties of the galaxy population and their environments over a large redshift range.
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    Affluence and emission tradeoffs: evidence from Indonesian households' carbon footprint 

    Irfany, Mohammad Iqbal; Klasen, Stephan
    Environment and Development Economics 2017; 22(05) p.546-570
    This study estimates Indonesian households’ carbon emissions that are attributed to their expenditures in 2005 and 2009 to analyze the pattern, distribution and drivers of their carbon footprint. Employing an input-output-emission-expenditure framework, the authors find a significant difference in household carbon emissions between different affluence levels, regions and educational levels. They also find that, while many household characteristics influence emissions, total expenditure is by far the most important determinant of household emissions, both across households and over time. Consequently, emissions inequality is very similar to expenditure inequality across households. The decomposition analysis confirms that changes in emissions are predominantly due to rising expenditures between the two periods, while expenditure elasticities analysis suggests that the rise in household emissions is mainly caused by the overall rise in total household expenditure, and not by shifting consumption shares among consumption categories. The paper discusses policy options for Indonesia to reduce this very strong expenditure–emissions link.
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    Efficient scheduling of astronomical observations 

    Garcia-Piquer, A.; Morales, J. C.; Ribas, I.; Colomé, J.; Guàrdia, J.; Perger, M.; Caballero, J. A.; Cortés-Contreras, M.; Jeffers, S. V.; Reiners, A.; et al.
    Amado, P. J.Quirrenbach, A.Seifert, W.
    Astronomy & Astrophysics 2017; 604 p.1-16: Art. A87
    Context. Targeted spectroscopic exoplanet surveys face the challenge of maximizing their planet detection rates by means of careful planning. For a large planet survey, the number of possible observation combinations, i.e., the sequence of observations night after night, both in total time and amount of targets, is enormous. Aims. Sophisticated scheduling tools and the improved understanding of the exoplanet population are employed to investigate an e cient and optimal way to plan the execution of observations. This is applied to the CARMENES instrument, which is an optical and infrared high-resolution spectrograph that has started a survey of about 300 M-dwarf stars in search of terrestrial exoplanets. Methods. We used evolutionary computation techniques to create an automatic scheduler that minimizes the idle periods of the telescope and distributes the observations among all the targets using configurable criteria.We simulated the case of the CARMENES survey with a realistic sample of targets, and we estimated the e ciency of the planning tool both in terms of telescope operations and planet detection. Results. Our scheduling simulations produce plans that use about 99% of the available telescope time (including overheads) and optimally distribute the observations among the di erent targets. Under such conditions, and using current planet statistics, the optimized plan using this tool should allow the CARMENES survey to discover about 65% of the planets with radial-velocity semi-amplitudes greater than 1 ms-1 when considering only photon noise. Conclusions. The simulations using our scheduling tool show that it is possible to optimize the survey planning by minimizing idle instrument periods and fulfilling the science objectives in an e cient manner to maximize the scientific return.
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    Kepler observations of the asteroseismic binary HD 176465 

    White, T. R.; Benomar, O.; Silva Aguirre, V.; Ball, W. H.; Bedding, T. R.; Chaplin, W. J.; Christensen-Dalsgaard, J.; Garcia, R. A.; Gizon, L.; Stello, D.; et al.
    Aigrain, S.Antia, H. M.Appourchaux, T.Bazot, M.Campante, T. L.Creevey, O. L.Davies, G. R.Elsworth, Y. P.Gaulme, P.Handberg, R.Hekker, S.Houdek, G.Howe, R.Huber, D.Karoff, C.Marques, J. P.Mathur, S.McQuillan, A.Metcalfe, T. S.Mosser, B.Nielsen, M. B.Régulo, C.Salabert, D.Stahn, T.
    Astronomy & Astrophysics 2017; 601 p.1-16: Art. A82
    Binary star systems are important for understanding stellar structure and evolution, and are especially useful when oscillations can be detected and analysed with asteroseismology. However, only four systems are known in which solar-like oscillations are detected in both components. Here, we analyse the fifth such system, HD 176465, which was observed by Kepler. We carefully analysed the system’s power spectrum to measure individual mode frequencies, adapting our methods where necessary to accommodate the fact that both stars oscillate in a similar frequency range. We also modelled the two stars independently by fitting stellar models to the frequencies and complementary parameters.We are able to cleanly separate the oscillation modes in both systems. The stellar models produce compatible ages and initial compositions for the stars, as is expected from their common and contemporaneous origin. Combining the individual ages, the system is about 3:0 0:5 Gyr old. The two components of HD 176465 are young physicallysimilar oscillating solar analogues, the first such system to be found, and provide important constraints for stellar evolution and asteroseismology.
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    Computational helioseismology in the frequency domain: acoustic waves in axisymmetric solar models with flows 

    Gizon, Laurent; Barucq, Hélène; Duruflé, Marc; Hanson, Chris S.; Leguèbe, Michael; Birch, Aaron C.; Chabassier, Juliette; Fournier, Damien; Hohage, Thorsten; Papini, Emanuele
    Astronomy & Astrophysics 2017; 600 p.1-23: Art. A35
    Context. Local helioseismology has so far relied on semi-analytical methods to compute the spatial sensitivity of wave travel times to perturbations in the solar interior. These methods are cumbersome and lack flexibility. Aims. Here we propose a convenient framework for numerically solving the forward problem of time-distance helioseismology in the frequency domain. The fundamental quantity to be computed is the cross-covariance of the seismic wavefield. Methods.We choose sources of wave excitation that enable us to relate the cross-covariance of the oscillations to the Green’s function in a straightforward manner. We illustrate the method by considering the 3D acoustic wave equation in an axisymmetric reference solar model, ignoring the e ects of gravity on the waves. The symmetry of the background model around the rotation axis implies that the Green’s function can be written as a sum of longitudinal Fourier modes, leading to a set of independent 2D problems. We use a high-order finite-element method to solve the 2D wave equation in frequency space. The computation is embarrassingly parallel, with each frequency and each azimuthal order solved independently on a computer cluster. Results. We compute travel-time sensitivity kernels in spherical geometry for flows, sound speed, and density perturbations under the first Born approximation. Convergence tests show that travel times can be computed with a numerical precision better than one millisecond, as required by the most precise travel-time measurements. Conclusions. The method presented here is computationally effcient and will be used to interpret travel-time measurements in order to infer, e.g., the large-scale meridional flow in the solar convection zone. It allows the implementation of (full-waveform) iterative inversions, whereby the axisymmetric background model is updated at each iteration.
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    Computational helioseismology in the frequency domain: acoustic waves in axisymmetric solar models with flows 

    Gizon, Laurent; Barucq, Hélène; Duruflé, Marc; Hanson, Chris S.; Leguèbe, Michael; Birch, Aaron C.; Chabassier, Juliette; Fournier, Damien; Hohage, Thorsten; Papini, Emanuele
    Astronomy & Astrophysics 2017; 600 p.1-23: Art. A35
    Context. Local helioseismology has so far relied on semi-analytical methods to compute the spatial sensitivity of wave travel times to perturbations in the solar interior. These methods are cumbersome and lack flexibility. Aims. Here we propose a convenient framework for numerically solving the forward problem of time-distance helioseismology in the frequency domain. The fundamental quantity to be computed is the cross-covariance of the seismic wavefield. Methods.We choose sources of wave excitation that enable us to relate the cross-covariance of the oscillations to the Green’s function in a straightforward manner. We illustrate the method by considering the 3D acoustic wave equation in an axisymmetric reference solar model, ignoring the e ects of gravity on the waves. The symmetry of the background model around the rotation axis implies that the Green’s function can be written as a sum of longitudinal Fourier modes, leading to a set of independent 2D problems. We use a high-order finite-element method to solve the 2D wave equation in frequency space. The computation is embarrassingly parallel, with each frequency and each azimuthal order solved independently on a computer cluster. Results. We compute travel-time sensitivity kernels in spherical geometry for flows, sound speed, and density perturbations under the first Born approximation. Convergence tests show that travel times can be computed with a numerical precision better than one millisecond, as required by the most precise travel-time measurements. Conclusions. The method presented here is computationally e cient and will be used to interpret travel-time measurements in order to infer, e.g., the large-scale meridional flow in the solar convection zone. It allows the implementation of (full-waveform) iterative inversions, whereby the axisymmetric background model is updated at each iteration.
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    Mechanistic Parameters of Electrocatalytic Water Oxidation on LiMn2O4 in Comparison to Natural Photosynthesis 

    Köhler, Lennart; Ebrahimizadeh Abrishami, Majid; Roddatis, Vladimir; Geppert, Janis; Risch, Marcel
    ChemSusChem 2017; 10(22) p.4479-4490
    Targeted improvement of the low efficiency of water oxidation during the oxygen evolution reaction (OER) is severely hindered by insufficient knowledge of the electrocatalytic mechanism on heterogeneous surfaces. We chose LiMn2O4 as a model system for mechanistic investigations as it shares the cubane structure with the active site of photosystem II and the valence of Mn3.5+ with the dark-stable S1 state in the mechanism of natural photosynthesis. The investigated LiMn2O4 nanoparticles are electrochemically stable in NaOH electrolytes and show respectable activity in any of the main metrics. At low overpotential, the key mechanistic parameters of Tafel slope, Nernst slope, and reaction order have constant values on the RHE scale of 62(1) mV dec−1, 1(1) mV pH−1, −0.04(2), respectively. These values are interpreted in the context of the well-studied mechanism of natural photosynthesis. The uncovered difference in the reaction sequence is important for the design of efficient bio-inspired electrocatalysts.
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