@article{LeonhardtGerhardtHoeppneretal.2016,
  author    = {Leonhardt, Helmar and Gerhardt, Matthias and Hoeppner, Nadine and Kr{\"u}ger, Kirsten and Tarantola, Marco and Beta, Carsten},
  title     = {Cell-substrate impedance fluctuations of single amoeboid cells encode cell-shape and adhesion dynamics},
  series = {Physical review : E, Statistical, nonlinear and soft matter physics},
  volume    = {93},
  journal   = {Physical review : E, Statistical, nonlinear and soft matter physics},
  publisher = {American Physical Society},
  address   = {College Park},
  issn      = {2470-0045},
  doi       = {10.1103/PhysRevE.93.012414},
  pages     = {8},
  year      = {2016},
  abstract  = {We show systematic electrical impedance measurements of single motile cells on microelectrodes. Wild-type cells and mutant strains were studied that differ in their cell-substrate adhesion strength. We recorded the projected cell area by time-lapse microscopy and observed irregular oscillations of the cell shape. These oscillations were correlated with long-term variations in the impedance signal. Superposed to these long-term trends, we observed fluctuations in the impedance signal. Their magnitude clearly correlated with the adhesion strength, suggesting that strongly adherent cells display more dynamic cell-substrate interactions.},
  language  = {en}
}
@article{SchreckPietzschKennedyetal.2016,
  author    = {Schreck, Simon and Pietzsch, Annette and Kennedy, Brian and Sathe, Conny and Miedema, Piter S. and Techert, Simone and Strocov, Vladimir N. and Schmitt, Thorsten and Hennies, Franz and Rubensson, Jan-Erik and F{\"o}hlisch, Alexander},
  title     = {Ground state potential energy surfaces around selected atoms from resonant inelastic x-ray scattering},
  series = {Scientific reports},
  volume    = {6},
  journal   = {Scientific reports},
  publisher = {Nature Publ. Group},
  address   = {London},
  issn      = {2045-2322},
  doi       = {10.1038/srep20054},
  pages     = {7},
  year      = {2016},
  abstract  = {Thermally driven chemistry as well as materials' functionality are determined by the potential energy surface of a systems electronic ground state. This makes the potential energy surface a central and powerful concept in physics, chemistry and materials science. However, direct experimental access to the potential energy surface locally around atomic centers and to its long-range structure are lacking. Here we demonstrate how sub-natural linewidth resonant inelastic soft x-ray scattering at vibrational resolution is utilized to determine ground state potential energy surfaces locally and detect long-range changes of the potentials that are driven by local modifications. We show how the general concept is applicable not only to small isolated molecules such as O2 but also to strongly interacting systems such as the hydrogen bond network in liquid water. The weak perturbation to the potential energy surface through hydrogen bonding is observed as a trend towards softening of the ground state potential around the coordinating atom. The instrumental developments in high resolution resonant inelastic soft x-ray scattering are currently accelerating and will enable broad application of the presented approach. With this multidimensional potential energy surfaces that characterize collective phenomena such as (bio)molecular function or high-temperature superconductivity will become accessible in near future.},
  language  = {en}
}
@article{RaetzelWilkensMenzel2016,
  author    = {R{\"a}tzel, Dennis and Wilkens, Martin and Menzel, Ralf},
  title     = {Gravitational properties of light-the gravitational field of a laser pulse},
  series = {NEW JOURNAL OF PHYSICS},
  volume    = {18},
  journal   = {NEW JOURNAL OF PHYSICS},
  publisher = {IOP Publ. Ltd.},
  address   = {Bristol},
  issn      = {1367-2630},
  doi       = {10.1088/1367-2630/18/2/023009},
  pages     = {16},
  year      = {2016},
  abstract  = {The gravitational field of a laser pulse of finite lifetime, is investigated in the framework of linearized gravity. Although the effects are very small, they may be of fundamental physical interest. It is shown that the gravitational field of a linearly polarized light pulse is modulated as the norm of the corresponding electric field strength, while no modulations arise for circular polarization. In general, the gravitational field is independent of the polarization direction. It is shown that all physical effects are confined to spherical shells expanding with the speed of light, and that these shells are imprints of the spacetime events representing emission and absorption of the pulse. Nearby test particles at rest are attracted towards the pulse trajectory by the gravitational field due to the emission of the pulse, and they are repelled from the pulse trajectory by the gravitational field due to its absorption. Examples are given for the size of the attractive effect. It is recovered that massless test particles do not experience any physical effect if they are co-propagating with the pulse, and that the acceleration of massless test particles counter-propagating with respect to the pulse is four times stronger than for massive particles at rest. The similarities between the gravitational effect of a laser pulse and Newtonian gravity in two dimensions are pointed out. The spacetime curvature close to the pulse is compared to that induced by gravitational waves from astronomical sources.},
  language  = {en}
}
@article{KappelArnoldHaus2016,
  author    = {Kappel, David and Arnold, Gabriele and Haus, Rainer},
  title     = {Multi-spectrum retrieval of Venus IR surface emissivity maps from VIRTIS/VEX nightside measurements at Themis Regio},
  series = {Icarus : international journal of solar system studies},
  volume    = {265},
  journal   = {Icarus : international journal of solar system studies},
  publisher = {Elsevier},
  address   = {San Diego},
  issn      = {0019-1035},
  doi       = {10.1016/j.icarus.2015.10.014},
  pages     = {42 -- 62},
  year      = {2016},
  abstract  = {Renormalized emissivity maps of Themis Regio at the three surface windows are determined from 64 measurement repetitions. Retrieval errors are estimated by a statistical evaluation of maps derived from various disjoint selections of spectra and using different assumptions on the interfering parameters. Double standard deviation errors for the three surface windows amount to 3\%, 8\%, and 4\%, respectively, allowing geologic interpretation. A comparison to results from an earlier error analysis based on synthetic spectra shows that unconsidered time variations of interfering atmospheric parameters are a major error source. Spatial variations of the 1.02 mu m surface emissivity of 20\% that correspond to the difference between unweathered granitic and basaltic rocks would be easily detectable, but such variations are ruled out for the studied target area. Emissivity anomalies of up to 8\% are detected at both 1.02 and 1.18 mu m. At present sensitivity, no anomalies are identified at 1.10 mu m, but anomalies exceeding the determined error level can be excluded. With single standard deviation significance, all three maps show interesting spatial emissivity variations. (C) 2015 Elsevier Inc. All rights reserved.},
  language  = {en}
}
@article{GeHeYan2016,
  author    = {Ge, J. X. and He, J. H. and Yan, Huirong},
  title     = {Effects of turbulent dust grain motion to interstellar chemistry},
  series = {Monthly notices of the Royal Astronomical Society},
  volume    = {455},
  journal   = {Monthly notices of the Royal Astronomical Society},
  publisher = {Oxford Univ. Press},
  address   = {Oxford},
  issn      = {0035-8711},
  doi       = {10.1093/mnras/stv2560},
  pages     = {3570 -- 3587},
  year      = {2016},
  abstract  = {Theoretical studies have revealed that dust grains are usually moving fast through the turbulent interstellar gas, which could have significant effects upon interstellar chemistry by modifying grain accretion. This effect is investigated in this work on the basis of numerical gas-grain chemical modelling. Major features of the grain motion effect in the typical environment of dark clouds (DC) can be summarized as follows: (1) decrease of gas-phase (both neutral and ionic) abundances and increase of surface abundances by up to 2-3 orders of magnitude; (2) shifts of the existing chemical jumps to earlier evolution ages for gas-phase species and to later ages for surface species by factors of about 10; (3) a few exceptional cases in which some species turn out to be insensitive to this effect and some other species can show opposite behaviours too. These effects usually begin to emerge from a typical DC model age of about 10(5) yr. The grain motion in a typical cold neutral medium (CNM) can help overcome the Coulomb repulsive barrier to enable effective accretion of cations on to positively charged grains. As a result, the grain motion greatly enhances the abundances of some gas-phase and surface species by factors up to 2-6 or more orders of magnitude in the CNM model. The grain motion effect in a typical molecular cloud (MC) is intermediate between that of the DC and CNM models, but with weaker strength. The grain motion is found to be important to consider in chemical simulations of typical interstellar medium.},
  language  = {en}
}
@article{PuhlmannHenkelHeueretal.2016,
  author    = {Puhlmann, Dirk and Henkel, Carsten and Heuer, Axel and Pieplow, Gregor and Menzel, Ralf},
  title     = {Characterization of a remote optical element with bi-photons},
  series = {Physica scripta : an international journal for experimental and theoretical physics},
  volume    = {91},
  journal   = {Physica scripta : an international journal for experimental and theoretical physics},
  publisher = {IOP Publ. Ltd.},
  address   = {Bristol},
  issn      = {0031-8949},
  doi       = {10.1088/0031-8949/91/2/023006},
  pages     = {113 -- 114},
  year      = {2016},
  abstract  = {We present a simple setup that exploits the interference of entangled photon pairs. 'Signal' photons are sent through a Mach-Zehnder-like interferometer, while 'idlers' are detected in a variable polarization state. Two-photon interference (in coincidence detection) is observed with very high contrast and for significant time delays between signal and idler detection events. This is explained by quantum erasure of the polarization tag and a delayed choice protocol involving a non-local virtual polarizer. The phase of the two-photon fringes is scanned by varying the path length in the signal beam or by rotating a birefringent crystal in the idler beam. We exploit this to characterize one beam splitter of the signal photon interferometer (reflection and transmission amplitudes including losses), using only information about coincidences and control parameters in the idler path. This is possible because our bi-photon state saturates the Greenberger-Yelin-Englert inequality between contrast and predictability.},
  language  = {en}
}
@misc{Metzler2016,
  author    = {Metzler, Ralf},
  title     = {PROTEIN PHYSICS Forever ageing},
  series = {Nature physics},
  volume    = {12},
  journal   = {Nature physics},
  publisher = {Nature Publ. Group},
  address   = {London},
  issn      = {1745-2473},
  doi       = {10.1038/nphys3585},
  pages     = {113 -- 114},
  year      = {2016},
  abstract  = {Single-molecule techniques have long given us insight into the motion and interactions of individual molecules. But simulations now show that the dynamics inside single proteins is not as simple as we thought — and that proteins are forever changing.},
  language  = {en}
}
@article{SandinSteffenSchoenberneretal.2016,
  author    = {Sandin, C. and Steffen, M. and Schoenberner, D. and R{\"u}hling, Ute},
  title     = {Hot bubbles of planetary nebulae with hydrogen-deficient winds I. Heat conduction in a chemically stratified plasma},
  series = {Frontiers in psychology},
  volume    = {586},
  journal   = {Frontiers in psychology},
  publisher = {EDP Sciences},
  address   = {Les Ulis},
  issn      = {1432-0746},
  doi       = {10.1051/0004-6361/201527357},
  pages     = {11},
  year      = {2016},
  abstract  = {Heat conduction has been found a plausible solution to explain discrepancies between expected and measured temperatures in hot bubbles of planetary nebulae (PNe). While the heat conduction process depends on the chemical composition, to date it has been exclusively studied for pure hydrogen plasmas in PNe. A smaller population of PNe show hydrogen-deficient and helium-and carbon-enriched surfaces surrounded by bubbles of the same composition; considerable differences are expected in physical properties of these objects in comparison to the pure hydrogen case. The aim of this study is to explore how a chemistry-dependent formulation of the heat conduction affects physical properties and how it affects the X-ray emission from PN bubbles of hydrogen-deficient stars. We extend the description of heat conduction in our radiation hydrodynamics code to work with any chemical composition. We then compare the bubble-formation process with a representative PN model using both the new and the old descriptions. We also compare differences in the resulting X-ray temperature and luminosity observables of the two descriptions. The improved equations show that the heat conduction in our representative model of a hydrogen-deficient PN is nearly as efficient with the chemistry-dependent description; a lower value on the diffusion coefficient is compensated by a slightly steeper temperature gradient. The bubble becomes somewhat hotter with the improved equations, but differences are otherwise minute. The observable properties of the bubble in terms of the X-ray temperature and luminosity are seemingly unaffected.},
  language  = {en}
}
@article{CioniBekkiGirardietal.2016,
  author    = {Cioni, Maria-Rosa L. and Bekki, Kenji and Girardi, Leo and de Grijs, Richard and Irwin, Mike J. and Ivanov, Valentin D. and Marconi, Marcella and Oliveira, Joana M. and Piatti, Andres E. and Ripepi, Vincenzo and van Loon, Jacco Th.},
  title     = {XVII. Proper motions of the Small Magellanic Cloud and the Milky Way globular cluster 47 Tucanae},
  series = {Physical review : E, Statistical, nonlinear and soft matter physics},
  volume    = {586},
  journal   = {Physical review : E, Statistical, nonlinear and soft matter physics},
  publisher = {EDP Sciences},
  address   = {Les Ulis},
  issn      = {1432-0746},
  doi       = {10.1051/0004-6361/201527004},
  pages     = {67 -- 75},
  year      = {2016},
  abstract  = {Aims. In this study we use multi-epoch near-infrared observations from the VISTA survey of the Magellanic Cloud system (VMC) to measure the proper motions of different stellar populations in a tile of 1.5 deg2 in size in the direction of the Galactic globular cluster 47 Tuc. We obtain the proper motion of the cluster itself, of the Small Magellanic Cloud (SMC), and of the field Milky Way stars. Methods. Stars of the three main stellar components are selected according to their spatial distributions and their distributions in colour\&\#8722;magnitude diagrams. Their average coordinate displacement is computed from the difference between multiple Ks-band observations for stars as faint as Ks = 19 mag. Proper motions are derived from the slope of the best-fitting line among ten VMC epochs over a time baseline of ~1 yr. Background galaxies are used to calibrate the absolute astrometric reference frame. Results. The resulting absolute proper motion of 47 Tuc is (\&\#956;\&\#945;cos(\&\#948;), \&\#956;\&\#948;) = (+7.26 ± 0.03, \&\#8722;1.25 ± 0.03) mas yr-1. This measurement refers to about 35 000 sources distributed between 10\&\#8242; and 60\&\#8242; from the cluster centre. For the SMC we obtain (\&\#956;\&\#945;cos(\&\#948;), \&\#956;\&\#948;) = (+1.16 ± 0.07, \&\#8722;0.81 ± 0.07) mas yr-1 from about 5250 red clump and red giant branch stars. The absolute proper motion of the Milky Way population in the line of sight (l = 305.9, b = \&\#8722;44.9) of this VISTA tile is (\&\#956;\&\#945;cos(\&\#948;), \&\#956;\&\#948;) = (+10.22 ± 0.14, \&\#8722;1.27 ± 0.12) mas yr-1 and has been calculated from about 4000 sources. Systematic uncertainties associated with the astrometric reference system are 0.18 mas yr-1. Thanks to the proper motion we detect 47 Tuc stars beyond its tidal radius.},
  language  = {en}
}
@article{KumphHenkelRabletal.2016,
  author    = {Kumph, Muir and Henkel, Carsten and Rabl, Peter and Brownnutt, Michael and Blatt, Rainer},
  title     = {Electric-field noise above a thin dielectric layer on metal electrodes},
  series = {NEW JOURNAL OF PHYSICS},
  volume    = {18},
  journal   = {NEW JOURNAL OF PHYSICS},
  publisher = {IOP Publ. Ltd.},
  address   = {Bristol},
  issn      = {1367-2630},
  doi       = {10.1088/1367-2630/18/2/023020},
  pages     = {1125 -- 1136},
  year      = {2016},
  abstract  = {The electric-field noise above a layered structure composed of a planar metal electrode covered by a thin dielectric is evaluated and it is found that the dielectric film considerably increases the noise level, in proportion to its thickness. Importantly, even a thin (mono) layer of a low-loss dielectric can enhance the noise level by several orders of magnitude compared to the noise above a bare metal. Close to this layered surface, the power spectral density of the electric field varies with the inverse fourth power of the distance to the surface, rather than with the inverse square, as it would above a bare metal surface. Furthermore, compared to a clean metal, where the noise spectrum does not vary with frequency (in the radio-wave and microwave bands), the dielectric layer can generate electricfield noise which scales in inverse proportion to the frequency. For various realistic scenarios, the noise levels predicted from this model are comparable to those observed in trapped-ion experiments. Thus, these findings are of particular importance for the understanding and mitigation of unwanted heating and decoherence in miniaturized ion traps.},
  language  = {en}
}
@article{GodecMetzler2016,
  author    = {Godec, Aljaz and Metzler, Ralf},
  title     = {First passage time distribution in heterogeneity controlled kinetics: going beyond the mean first passage time},
  series = {Scientific reports},
  volume    = {6},
  journal   = {Scientific reports},
  publisher = {Nature Publ. Group},
  address   = {London},
  issn      = {2045-2322},
  doi       = {10.1038/srep20349},
  pages     = {11},
  year      = {2016},
  abstract  = {The first passage is a generic concept for quantifying when a random quantity such as the position of a diffusing molecule or the value of a stock crosses a preset threshold (target) for the first time. The last decade saw an enlightening series of new results focusing mostly on the so-called mean and global first passage time (MFPT and GFPT, respectively) of such processes. Here we push the understanding of first passage processes one step further. For a simple heterogeneous system we derive rigorously the complete distribution of first passage times (FPTs). Our results demonstrate that the typical FPT significantly differs from the MFPT, which corresponds to the long time behaviour of the FPT distribution. Conversely, the short time behaviour is shown to correspond to trajectories connecting directly from the initial value to the target. Remarkably, we reveal a previously overlooked third characteristic time scale of the first passage dynamics mirroring brief excursion away from the target.},
  language  = {en}
}
@article{ZaksTomov2016,
  author    = {Zaks, Michael A. and Tomov, Petar},
  title     = {Onset of time dependence in ensembles of excitable elements with global repulsive coupling},
  series = {Physical review : E, Statistical, nonlinear and soft matter physics},
  volume    = {93},
  journal   = {Physical review : E, Statistical, nonlinear and soft matter physics},
  publisher = {American Physical Society},
  address   = {College Park},
  issn      = {2470-0045},
  doi       = {10.1103/PhysRevE.93.020201},
  pages     = {5},
  year      = {2016},
  abstract  = {We consider the effect of global repulsive coupling on an ensemble of identical excitable elements. An increase of the coupling strength destabilizes the synchronous equilibrium and replaces it with many attracting oscillatory states, created in the transcritical heteroclinic bifurcation. The period of oscillations is inversely proportional to the distance from the critical parameter value. If the elements interact with the global field via the first Fourier harmonics of their phases, the stable equilibrium is in one step replaced by the attracting continuum of periodic motions.},
  language  = {en}
}
@article{SebekToenjesKiss2016,
  author    = {Sebek, Michael and T{\"o}njes, Ralf and Kiss, Istvan Z.},
  title     = {Complex Rotating Waves and Long Transients in a Ring Network of Electrochemical Oscillators with Sparse Random Cross-Connections},
  series = {Physical review letters},
  volume    = {116},
  journal   = {Physical review letters},
  publisher = {American Physical Society},
  address   = {College Park},
  issn      = {0031-9007},
  doi       = {10.1103/PhysRevLett.116.068701},
  pages     = {3001 -- 3009},
  year      = {2016},
  abstract  = {We perform experiments and phase model simulations with a ring network of oscillatory electrochemical reactions to explore the effect of random connections and nonisochronicity of the interactions on the pattern formation. A few additional links facilitate the emergence of the fully synchronized state. With larger nonisochronicity, complex rotating waves or persistent irregular phase dynamics can derail the convergence to global synchronization. The observed long transients of irregular phase dynamics exemplify the possibility of a sudden onset of hypersynchronous behavior without any external stimulus or network reorganization.},
  language  = {en}
}
@misc{BattistonFarmerFlacheetal.2016,
  author    = {Battiston, Stefano and Farmer, J. Doyne and Flache, Andreas and Garlaschelli, Diego and Haldane, Andrew G. and Heesterbeek, Hans and Hommes, Cars and Jaeger, Carlo and May, Robert and Scheffer, Marten},
  title     = {COMPLEX SYSTEMS Complexity theory and financial regulation},
  series = {Science},
  volume    = {351},
  journal   = {Science},
  publisher = {American Assoc. for the Advancement of Science},
  address   = {Washington},
  issn      = {0036-8075},
  doi       = {10.1126/science.aad0299},
  pages     = {818 -- 819},
  year      = {2016},
  abstract  = {Traditional economic theory could not explain, much less predict, the near collapse of the financial system and its long-lasting effects on the global economy. Since the 2008 crisis, there has been increasing interest in using ideas from complexity theory to make sense of economic and financial markets. Concepts, such as tipping points, networks, contagion, feedback, and resilience have entered the financial and regulatory lexicon, but actual use of complexity models and results remains at an early stage. Recent insights and techniques offer potential for better monitoring and management of highly interconnected economic and financial systems and, thus, may help anticipate and manage future crises.},
  language  = {en}
}
@article{AbeysekaraArchambaultArcheretal.2016,
  author    = {Abeysekara, A. U. and Archambault, S. and Archer, A. and Benbow, W. and Bird, R. and Buchovecky, M. and Buckley, J. H. and Byrum, K. and Cardenzana, J. V. and Cerruti, M. and Chen, Xuhui and Christiansen, J. L. and Ciupik, L. and Cui, W. and Dickinson, H. J. and Eisch, J. D. and Errando, M. and Falcone, A. and Fegan, D. J. and Feng, Q. and Finley, J. P. and Fleischhack, H. and Fortin, P. and Fortson, L. and Furniss, A. and Gillanders, G. H. and Griffin, S. and Grube, J. and Gyuk, G. and Huetten, M. and Hakansson, Nils and Hanna, D. and Holder, J. and Humensky, T. B. and Johnson, C. A. and Kaaret, P. and Kar, P. and Kelley-Hoskins, N. and Kertzman, M. and Kieda, D. and Krause, M. and Krennrich, F. and Kumar, S. and Lang, M. J. and Lin, T. T. Y. and Maier, G. and McArthur, S. and McCann, A. and Meagher, K. and Moriarty, P. and Mukherjee, R. and Nieto, D. and Ong, R. A. and Otte, A. N. and Park, N. and Perkins, J. S. and Petrashyk, A. and Pohl, Martin and Popkow, A. and Pueschel, Elisa and Quinn, J. and Ragan, K. and Ratliff, G. and Reynolds, P. T. and Richards, G. T. and Roache, E. and Santander, M. and Sembroski, G. H. and Shahinyan, K. and Staszak, D. and Telezhinsky, Igor O. and Tucci, J. V. and Tyler, J. and Vincent, S. and Wakely, S. P. and Weiner, O. M. and Weinstein, A. and Williams, D. A. and Zitzer, B.},
  title     = {A SEARCH FOR BRIEF OPTICAL FLASHES ASSOCIATED WITH THE SETI TARGET KIC 8462852},
  series = {The astrophysical journal : an international review of spectroscopy and astronomical physics ; Part 2, Letters},
  volume    = {818},
  journal   = {The astrophysical journal : an international review of spectroscopy and astronomical physics ; Part 2, Letters},
  publisher = {IOP Publ. Ltd.},
  address   = {Bristol},
  issn      = {2041-8205},
  doi       = {10.3847/2041-8205/818/2/L33},
  pages     = {6},
  year      = {2016},
  abstract  = {The F-type star KIC. 8462852 has recently been identified as an exceptional target for search for extraterrestrial intelligence (SETI) observations. We describe an analysis methodology for optical SETI, which we have used to analyze nine hours of serendipitous archival observations of KIC. 8462852 made with the VERITAS gamma-ray observatory between 2009 and 2015. No evidence of pulsed optical beacons, above a pulse intensity at the Earth of approximately 1 photon m(-2), is found. We also discuss the potential use of imaging atmospheric Cherenkov telescope arrays in searching for extremely short duration optical transients in general.},
  language  = {en}
}
@article{LiuKliemTitovetal.2016,
  author    = {Liu, Rui and Kliem, Bernhard and Titov, Viacheslav S. and Chen, Jun and Wang, Yuming and Wang, Haimin and Liu, Chang and Xu, Yan and Wiegelmann, Thomas},
  title     = {STRUCTURE, STABILITY, AND EVOLUTION OF MAGNETIC FLUX ROPES FROM THE PERSPECTIVE OF MAGNETIC TWIST},
  series = {The astrophysical journal : an international review of spectroscopy and astronomical physics},
  volume    = {818},
  journal   = {The astrophysical journal : an international review of spectroscopy and astronomical physics},
  publisher = {IOP Publ. Ltd.},
  address   = {Bristol},
  issn      = {0004-637X},
  doi       = {10.3847/0004-637X/818/2/148},
  pages     = {22},
  year      = {2016},
  abstract  = {We investigate the evolution of NOAA Active Region (AR) 11817 during 2013 August 10-12, when it developed a complex field configuration and produced four confined, followed by two eruptive, flares. These C-and-above flares are all associated with a magnetic flux rope (MFR) located along the major polarity inversion line, where shearing and converging photospheric flows are present. Aided by the nonlinear force-free field modeling, we identify the MFR through mapping magnetic connectivities and computing the twist number \${{ \mathcal T }}_{w}\$ for each individual field line. The MFR is moderately twisted (\$| {{ \mathcal T }}_{w}| \lt 2\$) and has a well-defined boundary of high squashing factor Q. We found that the field line with the extremum \$| {{ \mathcal T }}_{w}| \$ is a reliable proxy of the rope axis, and that the MFR's peak \$| {{ \mathcal T }}_{w}| \$ temporarily increases within half an hour before each flare while it decreases after the flare peak for both confined and eruptive flares. This pre-flare increase in \$| {{ \mathcal T }}_{w}| \$ has little effect on the AR's free magnetic energy or any other parameters derived for the whole region, due to its moderate amount and the MFR's relatively small volume, while its decrease after flares is clearly associated with the stepwise decrease in the whole region's free magnetic energy due to the flare. We suggest that \${{ \mathcal T }}_{w}\$ may serve as a useful parameter in forewarning the onset of eruption, and therefore, the consequent space weather effects. The helical kink instability is identified as the prime candidate onset mechanism for the considered flares.},
  language  = {en}
}
@article{ShiEijtSandeepetal.2016,
  author    = {Shi, Wenqin and Eijt, Stephan W. H. and Sandeep, Chandramathi Sukumaran Suchand and Siebbeles, Laurens D. A. and Houtepen, Arjan J. and Kinge, Sachin and Bruck, Ekkes and Barbiellini, Bernardo and Bansil, Arun},
  title     = {Ligand-surface interactions and surface oxidation of colloidal PbSe quantum dots revealed by thin-film positron annihilation methods},
  series = {Applied physics letters},
  volume    = {108},
  journal   = {Applied physics letters},
  publisher = {American Institute of Physics},
  address   = {Melville},
  issn      = {0003-6951},
  doi       = {10.1063/1.4942609},
  pages     = {213 -- 230},
  year      = {2016},
  abstract  = {Positron Two Dimensional Angular Correlation of Annihilation Radiation (2D-ACAR) measurements reveal modifications of the electronic structure and composition at the surfaces of PbSe quantum dots (QDs), deposited as thin films, produced by various ligands containing either oxygen or nitrogen atoms. In particular, the 2D--ACAR measurements on thin films of colloidal PbSe QDs capped with oleic acid ligands yield an increased intensity in the electron momentum density (EMD) at high momenta compared to PbSe quantum dots capped with oleylamine. Moreover, the EMD of PbSe QDs is strongly affected by the small ethylenediamine ligands, since these molecules lead to small distances between QDs and favor neck formation between near neighbor QDs, inducing electronic coupling between neighboring QDs. The high sensitivity to the presence of oxygen atoms at the surface can be also exploited to monitor the surface oxidation of PbSe QDs upon exposure to air. Our study clearly demonstrates that positron annihilation spectroscopy applied to thin films can probe surface transformations of colloidal semiconductor QDs embedded in functional layers. (C) 2016 AIP Publishing LLC.},
  language  = {en}
}
@article{LenskeWagnerWirthetal.2016,
  author    = {Lenske, Gerlinde and Wagner, Wolfgang and Wirth, Joachim and Thillmann, Hubertina and Cauet, Eva and Liepertz, Sven and Leutner, Detlev},
  title     = {The importance of pedagogical knowledge for classroom management and for and for students' achievement},
  series = {Zeitschrift f{\~A}¼r Erziehungswissenschaft},
  volume    = {19},
  journal   = {Zeitschrift f{\~A}¼r Erziehungswissenschaft},
  publisher = {Springer},
  address   = {Wiesbaden},
  issn      = {1434-663X},
  doi       = {10.1007/s11618-015-0659-x},
  pages     = {211 -- 233},
  year      = {2016},
  abstract  = {Im Rahmen der vorliegenden Studie wurde untersucht, ob das p{\"a}dagogisch-psychologische Wissen von Lehrkr{\"a}ften die prozessuale Qualit{\"a}t des Physikunterrichts mit Blick auf die Klassenf{\"u}hrung und den Lernzuwachs der Sch{\"u}lerinnen und Sch{\"u}ler beeinflusst. Das p{\"a}dagogisch-psychologische Professionswissen, konzeptualisiert als ein f{\"a}cher{\"u}bergreifendes, handlungsleitendes Wissen {\"u}ber Strategien und Mittel zur Unterrichtsgestaltung, wurde {\"u}ber einen Paper-Pencil-Test, bestehend aus einer Skala zum deklarativen und einer Skala zum konditional-prozeduralen Wissen erhoben (Lenske et al. 2015). Als ein grundlegendes Merkmal prozessualer Unterrichtsqualit{\"a}t wurde die Klassenf{\"u}hrung anhand von Videoratings zu zwei Messzeitpunkten (zwei Unterrichtsstunden) erfasst. Der Lernzuwachs der Sch{\"u}lerinnen und Sch{\"u}ler wurde {\"u}ber standardisierte Fachwissenstests im Pr{\"a}-Post-Testdesign gemessen. Die Stichprobe umfasst 34 Gymnasiallehrkr{\"a}fte und deren Sch{\"u}lerinnen und Sch{\"u}ler (N = 993). Auf Basis eines Complex-Bootstrap-Mediations-Modells zeigte sich, dass das p{\"a}dagogisch-psychologische Professionswissen {\"u}ber die Klassenf{\"u}hrung vermittelt den Lernzuwachs der Sch{\"u}ler und Sch{\"u}lerinnen positiv beeinflusst. In the present study it was investigated whether the pedagogical knowledge of teachers has an influence on the process quality of physics instruction and on the learning achievement of students as well. Pedagogical knowledge, conceptualized as knowledge about strategies in classroom instruction that is domain-general and relevant for teaching behaviors, was measured using a paper-and-pencil test with two scales: one scale on declarative knowledge, the other on conditional-procedural knowledge (Lenske et al. 2015). As a basic aspect of the process quality of classroom instruction, classroom management was assessed using video ratings of two lessons from each participating teacher. Students' learning achievement was assessed using standardized domain-specific knowledge tests in a pretest-posttest design. The sample included 34 teachers from higher-track secondary schools and their students (N = 993). A complex bootstrapping mediation model shows that teachers' pedagogical knowledge, mediated by their classroom management, has a positive effect on their students' learning achievement.},
  language  = {de}
}
@article{ReinhardtKocLeitenbergeretal.2016,
  author    = {Reinhardt, Matthias and Koc, Azize and Leitenberger, Wolfram and Gaal, Peter and Bargheer, Matias},
  title     = {Optimized spatial overlap in optical pump-X-ray probe experiments with high repetition rate using laser-induced surface distortions},
  series = {Journal of synchrotron radiation},
  volume    = {23},
  journal   = {Journal of synchrotron radiation},
  publisher = {International Union of Crystallography},
  address   = {Chester},
  issn      = {1600-5775},
  doi       = {10.1107/S1600577515024443},
  pages     = {474 -- 479},
  year      = {2016},
  abstract  = {Ultrafast X-ray diffraction experiments require careful adjustment of the spatial overlap between the optical excitation and the X-ray probe pulse. This is especially challenging at high laser repetition rates. Sample distortions caused by the large heat load on the sample and the relatively low optical energy per pulse lead to only tiny signal changes. In consequence, this results in small footprints of the optical excitation on the sample, which turns the adjustment of the overlap difficult. Here a method for reliable overlap adjustment based on reciprocal space mapping of a laser excited thin film is presented.},
  language  = {en}
}
@article{EckertMiedemaQuevedoetal.2016,
  author    = {Eckert, Sebastian and Miedema, P. S. and Quevedo, W. and Fondell, Mattis and Beye, Martin and Pietzsch, Annette and Ross, M. and Khalil, M. and F{\"o}hlisch, Alexander},
  title     = {Molecular structures and protonation state of 2-Mercaptopyridine in aqueous solution},
  series = {Chemical physics letters},
  volume    = {647},
  journal   = {Chemical physics letters},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0009-2614},
  doi       = {10.1016/j.cplett.2016.01.050},
  pages     = {103 -- 106},
  year      = {2016},
  abstract  = {The speciation of 2-Mercaptopyridine in aqueous solution has been investigated with nitrogen 1s Near Edge X-ray Absorption Fine Structure spectroscopy and time dependent Density Functional Theory. The prevalence of distinct species as a function of the solvent basicity is established. No indications of dimerization towards high concentrations are found. The determination of different molecular structures of 2-Mercaptopyridine in aqueous solution is put into the context of proton-transfer in keto-enol and thione-thiol tautomerisms. (C) 2016 The Authors. Published by Elsevier B.V.},
  language  = {en}
}