TY  - JOUR
A1  - Zhang, Xiaoqing
A1  - Zhang, Xinwu
A1  - You, Qiong
A1  - Sessler, Gerhard M.
T1  - Low- cost, large- area, stretchable  piezoelectric films based on irradiation- crosslinked poly ( propylene)
JF  - Macromolecular materials and engineering
N2  - Low cost, large area, lightweight, stretchable piezoelectric films, based on space-charge electret with a foam structure (i.e., ferroelectrets or piezoelectrets), have been fabricated by using commercially available irradiation cross-linked poly(propylene) (IXPP) foam sheets. Piezoelectric d(33) coefficients are as high as 100pCN(-1). The piezoelectric performance in such IXPP films is well preserved for repeated strains of less than 10%. Piezoelectric d(33) coefficients are frequency independent in the range from 2 to 100Hz. Such new class materials may be applied in sensory skins, smart clothing, bio-inspired systems, microenergy harvesters, and so on.
KW  - crosslinked poly(propylene)
KW  - ferroelectret
KW  - piezoelectricity
KW  - stretchability
Y1  - 2014
U6  - https://doi.org/10.1002/mame.201300161
SN  - 1438-7492
SN  - 1439-2054
VL  - 299
IS  - 3
SP  - 290
EP  - 295
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Schick, Daniel
A1  - Herzog, Marc
A1  - Wen, Haidan
A1  - Chen, Pice
A1  - Adamo, Carolina
A1  - Gaal, Peter
A1  - Schlom, Darrell G.
A1  - Evans, Paul G.
A1  - Li, Yuelin
A1  - Bargheer, Matias
T1  - Localized excited charge carriers generate ultrafast inhomogeneous strain in the multiferroic BiFeO3
JF  - Physical review letters
N2  - We apply ultrafast x-ray diffraction with femtosecond temporal resolution to monitor the lattice dynamics in a thin film of multiferroic BiFeO3 after above-band-gap photoexcitation. The sound-velocity limited evolution of the observed lattice strains indicates a quasi-instantaneous photoinduced stress which decays on a nanosecond time scale. This stress exhibits an inhomogeneous spatial profile evidenced by the broadening of the Bragg peak. These new data require substantial modification of existing models of photogenerated stresses in BiFeO3: the relevant excited charge carriers must remain localized to be consistent with the data.
Y1  - 2014
U6  - https://doi.org/10.1103/PhysRevLett.112.097602
SN  - 0031-9007
SN  - 1079-7114
VL  - 112
IS  - 9
PB  - American Physical Society
CY  - College Park
ER  - 
TY  - JOUR
A1  - Kang, Yu
A1  - Barbirz, Stefanie
A1  - Lipowsky, Reinhard
A1  - Santer, Mark
T1  - Conformational Diversity of O-Antigen Polysaccharides of the Gram-Negative Bacterium Shigella flexneri Serotype Y
JF  - The journal of physical chemistry : B, Condensed matter, materials, surfaces, interfaces & biophysical chemistry
Y1  - 2014
U6  - https://doi.org/10.1021/jp4111713
SN  - 1520-6106
VL  - 118
IS  - 9
SP  - 2523
EP  - 2534
PB  - American Chemical Society
CY  - Washington
ER  - 
TY  - JOUR
A1  - Goychuk, Igor
A1  - Kharchenko, Vasyl O.
A1  - Metzler, Ralf
T1  - How Molecular Motors Work in the Crowded Environment of Living Cells: Coexistence and Efficiency of Normal and Anomalous Transport
JF  - PLoS one
N2  - Recent experiments reveal both passive subdiffusion of various nanoparticles and anomalous active transport of such particles by molecular motors in the molecularly crowded environment of living biological cells. Passive and active microrheology reveals that the origin of this anomalous dynamics is due to the viscoelasticity of the intracellular fluid. How do molecular motors perform in such a highly viscous, dissipative environment? Can we explain the observed co-existence of the anomalous transport of relatively large particles of 100 to 500 nm in size by kinesin motors with the normal transport of smaller particles by the same molecular motors? What is the efficiency of molecular motors in the anomalous transport regime? Here we answer these seemingly conflicting questions and consistently explain experimental findings in a generalization of the well-known continuous diffusion model for molecular motors with two conformational states in which viscoelastic effects are included.
Y1  - 2014
U6  - https://doi.org/10.1371/journal.pone.0091700
SN  - 1932-6203
VL  - 9
IS  - 3
PB  - PLoS
CY  - San Fransisco
ER  - 
TY  - JOUR
A1  - Steyrleuthner, Robert
A1  - Di Pietro, Riccardo
A1  - Collins, Brian A.
A1  - Polzer, Frank
A1  - Himmelberger, Scott
A1  - Schubert, Marcel
A1  - Chen, Zhihua
A1  - Zhang, Shiming
A1  - Salleo, Alberto
A1  - Ade, Harald W.
A1  - Facchetti, Antonio
A1  - Neher, Dieter
T1  - The Role of Regioregularity, Crystallinity, and Chain Orientation on Electron Transport in a High-Mobility n-Type Copolymer
JF  - Journal of the American Chemical Society
Y1  - 2014
U6  - https://doi.org/10.1021/ja4118736
SN  - 0002-7863
VL  - 136
IS  - 11
SP  - 4245
EP  - 4256
PB  - American Chemical Society
CY  - Washington
ER  - 
TY  - INPR
A1  - Föhlisch, Alexander
A1  - de Groot, F. M. F.
A1  - Odelius, Michael
A1  - Techert, Simone
A1  - Wernet, P.
T1  - Comment on "state-dependent electron delocalization dynamics at the solute-solvent interface: soft-x-ray absorption spectroscopy and lambda b initio calculations"
T2  - Physical review letters
Y1  - 2014
U6  - https://doi.org/10.1103/PhysRevLett.112.129302
SN  - 0031-9007
SN  - 1079-7114
VL  - 112
IS  - 12
PB  - American Physical Society
CY  - College Park
ER  - 
TY  - JOUR
A1  - Talukder, Srijeeta
A1  - Sen, Shrabani
A1  - Chakraborti, Prantik
A1  - Metzler, Ralf
A1  - Banik, Suman K.
A1  - Chaudhury, Pinaki
T1  - Breathing dynamics based parameter sensitivity analysis of hetero-polymeric DNA
JF  - The journal of chemical physics : bridges a gap between journals of physics and journals of chemistr
N2  - We study the parameter sensitivity of hetero-polymeric DNA within the purview of DNA breathing dynamics. The degree of correlation between the mean bubble size and the model parameters is estimated for this purpose for three different DNA sequences. The analysis leads us to a better understanding of the sequence dependent nature of the breathing dynamics of hetero-polymeric DNA. Out of the 14 model parameters for DNA stability in the statistical Poland-Scheraga approach, the hydrogen bond interaction epsilon(hb)(AT) for an AT base pair and the ring factor. turn out to be the most sensitive parameters. In addition, the stacking interaction epsilon(st)(TA-TA) for an TA-TA nearest neighbor pair of base-pairs is found to be the most sensitive one among all stacking interactions. Moreover, we also establish that the nature of stacking interaction has a deciding effect on the DNA breathing dynamics, not the number of times a particular stacking interaction appears in a sequence. We show that the sensitivity analysis can be used as an effective measure to guide a stochastic optimization technique to find the kinetic rate constants related to the dynamics as opposed to the case where the rate constants are measured using the conventional unbiased way of optimization. (c) 2014 AIP Publishing LLC.
Y1  - 2014
U6  - https://doi.org/10.1063/1.4869112
SN  - 0021-9606
SN  - 1089-7690
VL  - 140
IS  - 12
PB  - American Institute of Physics
CY  - Melville
ER  - 
TY  - JOUR
A1  - Reibis, Rona Katharina
A1  - Völler, Heinz
A1  - Gitt, Anselm
A1  - Jannowitz, Christina
A1  - Halle, Martin
A1  - Pittrow, David
A1  - Hildemann, Steven
T1  - Management of patients with ST- segment elevation or non- ST- segment elevation acute coronary syndromes in cardiac rehabilitation centers
JF  - Clinical cardiology : international journal for cardiovascular diseases
N2  - BackgroundCurrent data on the management of patients in cardiac rehabilitation (CR) after an acute hospital stay due to ST-segment elevation or non-ST segment elevation acute coronary syndromes (STE-ACS or NSTE-ACS) are limited. We aimed to describe patient characteristics, risk factor management, and lipid target achievement of patients in CR in Germany and compare the 2 groups.
 HypothesisWith respect to the risk factor pattern and treatment effects during a CR stay, there are important differences between STE-ACS and NSTE-ACS patients.
 MethodsComparison of 7950 patients by STE-ACS or NSTE-ACS status in the Transparency Registry to Objectify Guideline-Oriented Risk Factor Management registry (2010) who underwent an inpatient CR period of about 3 weeks.
 ResultsSTE-ACS patients compared to NSTE-ACS patients were significantly younger (60.5 vs 64.4 years, P < 0.0001), and had diabetes mellitus, hypertension, or any risk factor (exception: smoking) less often. At discharge, in STE-ACS compared to NSTE-ACS patients, the low-density lipoprotein cholesterol (LDL-C) <100 mg/dL goal was achieved by 75.3% and 76.2%, respectively (LDL-C <70 mg/dL by 27.7% and 27.4%), the high-density lipoprotein cholesterol goal of >50 mg/dL in women and >40 mg/dL in men was achieved by 49.3% and 49.0%, respectively, and the triglycerides goal of <150 mg/dl was achievedby 72.3% and 74.3%, respectively (all comparisons not significant). Mean systolic and diastolic blood pressure were 121/74 and 123/74 mm Hg, respectively (P < 0.0001 systolic, diastolic not significant). The maximum exercise capacity was 110 and 102 W, respectively (P < 0.0001), and the maximum walking distance was 581 and 451 meters, respectively (P value not significant).
 ConclusionsPatients with STE-ACS and NSTE-ACS differed moderately in their baseline characteristics. Both groups benefited from the participation in CR, as their lipid profile, blood pressure, and physical fitness improved.
Y1  - 2014
U6  - https://doi.org/10.1002/clc.22241
SN  - 0160-9289
SN  - 1932-8737
VL  - 37
IS  - 4
SP  - 213
EP  - 221
PB  - Wiley-Blackwell
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - Albrecht, Steve
A1  - Vandewal, Koen
A1  - Tumbleston, John R.
A1  - Fischer, Florian S. U.
A1  - Douglas, Jessica D.
A1  - Frechet, Jean M. J.
A1  - Ludwigs, Sabine
A1  - Ade, Harald W.
A1  - Salleo, Alberto
A1  - Neher, Dieter
T1  - On the efficiency of charge transfer state splitting in polymer: Fullerene solar cells
JF  - Advanced materials
KW  - organic solar cells
KW  - charge generation
KW  - geminate recombination
KW  - charge transfer states
KW  - driving force
KW  - excess energy
KW  - morphology
KW  - spectroelectrochemistry
Y1  - 2014
U6  - https://doi.org/10.1002/adma.201305283
SN  - 0935-9648
SN  - 1521-4095
VL  - 26
IS  - 16
SP  - 2533
EP  - 2539
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Hubrig, Swetlana
A1  - Fossati, Luca
A1  - Carroll, Thorsten Anthony
A1  - Castro, Norberto
A1  - Gonzalez, J. F.
A1  - Ilyin, Ilya
A1  - Przybilla, Norbert
A1  - Schoeller, M.
A1  - Oskinova, Lidia M.
A1  - Morel, T.
A1  - Langer, N.
A1  - Scholz, Ralf-Dieter
A1  - Kharchenko, N. V.
A1  - Nieva, M. -F.
T1  - B fields in OB stars (BOB): The discovery of a magnetic field in a multiple system in the Trifid nebula, one of the youngest star forming regions
JF  - Astronomy and astrophysics : an international weekly journal
N2  - Aims. Recent magnetic field surveys in O- and B-type stars revealed that about 10% of the core-hydrogen-burning massive stars host large-scale magnetic fields. The physical origin of these fields is highly debated. To identify and model the physical processes responsible for the generation of magnetic fields in massive stars, it is important to establish whether magnetic massive stars are found in very young star-forming regions or whether they are formed in close interacting binary systems.
 Methods. In the framework of our ESO Large Program, we carried out low-resolution spectropolarimetric observations with FORS 2 in 2013 April of the three most massive central stars in the Trifid nebula, HD 164492A, HD 164492C, and HD 164492D. These observations indicated a strong longitudinal magnetic field of about 500-600 G in the poorly studied component HD 164492C. To confirm this detection, we used HARPS in spectropolarimetric mode on two consecutive nights in 2013 June.
 Results. Our HARPS observations confirmed the longitudinal magnetic field in HD 164492C. Furthermore, the HARPS observations revealed that HD 164492C cannot be considered as a single star as it possesses one or two companions. The spectral appearance indicates that the primary is most likely of spectral type B1-B1.5 V. Since in both observing nights most spectral lines appear blended, it is currently unclear which components are magnetic. Long-term monitoring using high-resolution spectropolarimetry is necessary to separate the contribution of each component to the magnetic signal. Given the location of the system HD 164492C in one of the youngest star formation regions, this system can be considered as a Rosetta Stone for our understanding of the origin of magnetic fields in massive stars.
KW  - binaries: close
KW  - stars: early-type
KW  - stars: fundamental parameters
KW  - stars: magnetic field
KW  - stars: variables: general
KW  - stars: individual: HD 164492C
Y1  - 2014
U6  - https://doi.org/10.1051/0004-6361/201423490
SN  - 0004-6361
SN  - 1432-0746
VL  - 564
PB  - EDP Sciences
CY  - Les Ulis
ER  - 
TY  - JOUR
A1  - Abramowski, Attila
A1  - Aharonian, Felix A.
A1  - Benkhali, Faical  Ait
A1  - Akhperjanian, A. G.
A1  - Angüner, Ekrem Oǧuzhan
A1  - Anton, Gisela
A1  - Balenderan, Shangkari
A1  - Balzer, Arnim
A1  - Barnacka, Anna
A1  - Becherini, Yvonne
A1  - Tjus, J. Becker
A1  - Bernlöhr, K.
A1  - Birsin, E.
A1  - Bissaldi, E.
A1  - Biteau, Jonathan
A1  - Boettcher, Markus
A1  - Boisson, Catherine
A1  - Bolmont, J.
A1  - Bordas, Pol
A1  - Brucker, J.
A1  - Brun, Francois
A1  - Brun, Pierre
A1  - Bulik, Tomasz
A1  - Carrigan, Svenja
A1  - Casanova, Sabrina
A1  - Cerruti, M.
A1  - Chadwick, Paula M.
A1  - Chalme-Calvet, R.
A1  - Chaves, Ryan C. G.
A1  - Cheesebrough, A.
A1  - Chretien, M.
A1  - Colafrancesco, Sergio
A1  - Cologna, Gabriele
A1  - Conrad, Jan
A1  - Couturier, C.
A1  - Cui, Y.
A1  - Dalton, M.
A1  - Daniel, M. K.
A1  - Davids, I. D.
A1  - Degrange, B.
A1  - Deil, C.
A1  - dewilt, P.
A1  - Dicldnson, H. J.
A1  - Djannati-Ataï, A.
A1  - Domainko, W.
A1  - Dubus, G.
A1  - Dutson, K.
A1  - Dyks, J.
A1  - Dyrda, M.
A1  - Edwards, T.
A1  - Egberts, Kathrin
A1  - Eger, P.
A1  - Espigat, P.
A1  - Farnier, C.
A1  - Fegan, S.
A1  - Feinstein, F.
A1  - Fernandes, M. V.
A1  - Fernandez, D.
A1  - Fiasson, A.
A1  - Fontaine, G.
A1  - Foerster, A.
A1  - Fuessling, M.
A1  - Gajdus, M.
A1  - Gallant, Y. A.
A1  - Garrigoux, T.
A1  - Giavitto, G.
A1  - Giebels, B.
A1  - Glicenstein, J. F.
A1  - Grondin, M. -H.
A1  - Grudzinska, M.
A1  - Haeffner, S.
A1  - Hahn, J.
A1  - Harris, J.
A1  - Heinzelmann, G.
A1  - Henri, G.
A1  - Hermann, G.
A1  - Hervet, O.
A1  - Hillert, A.
A1  - Hinton, James Anthony
A1  - Hofmann, W.
A1  - Hofverberg, P.
A1  - Holler, M.
A1  - Horns, D.
A1  - Jacholkowska, A.
A1  - Jahn, C.
A1  - Jamrozy, M.
A1  - Janiak, M.
A1  - Jankowsky, F.
A1  - Jung, I.
A1  - Kastendieck, M. A.
A1  - Katarzynski, K.
A1  - Katz, U.
A1  - Kaufmann, S.
A1  - Khelifi, B.
A1  - Kieffer, M.
A1  - Klepser, S.
A1  - Klochkov, D.
A1  - Kluzniak, W.
A1  - Kneiske, T.
A1  - Kolitzus, D.
A1  - Komin, Nu.
A1  - Kosack, K.
A1  - Krakau, S.
A1  - Krayzel, F.
A1  - Krueger, P. P.
A1  - Laffon, H.
A1  - Lamanna, G.
A1  - Lefaucheur, J.
A1  - Lemiere, A.
A1  - Lemoine-Goumard, M.
A1  - Lenain, J. -P.
A1  - Lennarz, D.
A1  - Lohse, T.
A1  - Lopatin, A.
A1  - Lu, C. -C.
A1  - Marandon, V.
A1  - Marcowith, Alexandre
A1  - Marx, R.
A1  - Maurin, G.
A1  - Maxted, N.
A1  - Mayer, M.
A1  - McComb, T. J. L.
A1  - Mehault, J.
A1  - Meintjes, P. J.
A1  - Menzler, U.
A1  - Meyer, M.
A1  - Moderski, R.
A1  - Mohamed, M.
A1  - Moulin, Emmanuel
A1  - Murach, T.
A1  - Naumann, C. L.
A1  - de Naurois, M.
A1  - Niemiec, J.
A1  - Nolan, S. J.
A1  - Oakes, L.
A1  - Ohm, S.
A1  - Wilhelmi, E. de Ona
A1  - Opitz, B.
A1  - Ostrowski, M.
A1  - Oya, I.
A1  - Panter, M.
A1  - Parsons, R. D.
A1  - Arribas, M. Paz
A1  - Pekeur, N. W.
A1  - Pelletier, G.
A1  - Perez, J.
A1  - Petrucci, P. -O.
A1  - Peyaud, B.
A1  - Pita, S.
A1  - Poon, H.
A1  - Puehlhofer, G.
A1  - Punch, M.
A1  - Quirrenbach, A.
A1  - Raab, S.
A1  - Raue, M.
A1  - Reimer, A.
A1  - Reimer, O.
A1  - Renaud, M.
A1  - Reyes, R. de Los
A1  - Rieger, F.
A1  - Rob, L.
A1  - Romoli, C.
A1  - Rosier-Lees, S.
A1  - Rowell, G.
A1  - Rudak, B.
A1  - Rulten, C. B.
A1  - Sahakian, V.
A1  - Sanchez, David M.
A1  - Santangelo, Andrea
A1  - Schlickeiser, R.
A1  - Schuessler, F.
A1  - Schulz, A.
A1  - Schwanke, U.
A1  - Schwarzburg, S.
A1  - Schwemmer, S.
A1  - Sol, H.
A1  - Spengler, G.
A1  - Spies, F.
A1  - Stawarz, L.
A1  - Steenkamp, R.
A1  - Stegmann, Christian
A1  - Stinzing, F.
A1  - Stycz, K.
A1  - Sushch, Iurii
A1  - Szostek, A.
A1  - Tavernet, J. -P.
A1  - Tavernier, T.
A1  - Taylor, A. M.
A1  - Terrier, R.
A1  - Tluczykont, M.
A1  - Trichard, C.
A1  - Valerius, K.
A1  - van Eldik, C.
A1  - van Soelen, B.
A1  - Vasileiadis, G.
A1  - Venter, C.
A1  - Viana, A.
A1  - Vincent, P.
A1  - Voelk, H. J.
A1  - Volpe, F.
A1  - Vorster, M.
A1  - Vuillaume, T.
A1  - Wagner, S. J.
A1  - Wagner, P.
A1  - Ward, M.
A1  - Weidinger, M.
A1  - Weitzel, Q.
A1  - White, R.
A1  - Wierzcholska, A.
A1  - Willmann, P.
A1  - Woernlein, A.
A1  - Wouters, D.
A1  - Zabalza, V.
A1  - Zacharias, M.
A1  - Zajczyk, A.
A1  - Zdziarski, A. A.
A1  - Zech, Alraune
A1  - Zechlin, H. -S.
T1  - Flux upper limits for 47 AGN observed with HESS in 2004-2011
JF  - Astronomy and astrophysics : an international weekly journal
N2  - Context. About 40% of the observation time of the High Energy Stereoscopic System (H.E.S.S.) is dedicated to studying active galactic nuclei (AGN), with the aim of increasing the sample of known extragalactic very-high-energy (VHE, E > 100 GeV) sources and constraining the physical processes at play in potential emitters.
 Aims. H.E.S.S. observations of AGN, spanning a period from April 2004 to December 2011, are investigated to constrain their gamma-ray fluxes. Only the 47 sources without significant excess detected at the position of the targets are presented.
 Methods. Upper limits on VHE fluxes of the targets were computed and a search for variability was performed on the nightly time scale.
 Results. For 41 objects, the flux upper limits we derived are the most constraining reported to date. These constraints at VHE are compared with the flux level expected from extrapolations of Fermi-LAT measurements in the two-year catalog of AGN. The H.E.S.S. upper limits are at least a factor of two lower than the extrapolated Fermi-LAT fluxes for 11 objects Taking into account the attenuation by the extragalactic background light reduces the tension for all but two of them, suggesting intrinsic curvature in the high-energy spectra of these two AGN.
 Conclusions. Compilation efforts led by current VHE instruments are of critical importance for target-selection strategies before the advent of the Cherenkov Telescope Array (CTA).
KW  - gamma rays: galaxies
KW  - galaxies: active
Y1  - 2014
U6  - https://doi.org/10.1051/0004-6361/201322897
SN  - 0004-6361
SN  - 1432-0746
VL  - 564
PB  - EDP Sciences
CY  - Les Ulis
ER  - 
TY  - JOUR
A1  - Goldshteyn, Jevgeni
A1  - Bojahr, Andre
A1  - Gaal, Peter
A1  - Schick, Daniel
A1  - Bargheer, Matias
T1  - Selective preparation and detection of phonon polariton wavepackets by stimulated Raman scattering
JF  - Physica status solidi : Physica status solidi
N2  - Wavevector-selective impulsive excitation of phonon-polaritons by a spectrally broad femtosecond transient grating produces wavepackets propagating in opposite directions. The photons in spectrally narrow probe pulses are scattered from these elementary excitations in lithium niobate (LiNbO3). Both elastically and inelastically scattered photons are simultaneously detected in a spectrometer. The Stokes- and anti-Stokes shifted probe pulses uniquely determine the propagation direction of the detected polariton wavepacket components and correspond to creation or annihilation of phonon-polaritons. Our experiments with spectrally broad pump and spectrally narrow probe pulses allows dissecting the four-wave-mixing process into two sequential stimulated Raman scattering events.
Y1  - 2014
U6  - https://doi.org/10.1002/pssb.201350114
SN  - 0370-1972
SN  - 1521-3951
VL  - 251
IS  - 4
SP  - 821
EP  - 828
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Danehkar, A.
A1  - Todt, Helge Tobias
A1  - Ercolano, B.
A1  - Kniazev, A. Y.
T1  - Observations and three-dimensional photoionization modelling of the Wolf-Rayet planetary nebula Abell 48(star)
JF  - Monthly notices of the Royal Astronomical Society
N2  - Recent observations reveal that the central star of the planetary nebula Abell 48 exhibits spectral features similar to massive nitrogen-sequence Wolf-Rayet stars. This raises a pertinent question, whether it is still a planetary nebula or rather a ring nebula of a massive star. In this study, we have constructed a three-dimensional photoionization model of Abell 48, constrained by our new optical integral field spectroscopy. An analysis of the spatially resolved velocity distributions allowed us to constrain the geometry of Abell 48. We used the collisionally excited lines to obtain the nebular physical conditions and ionic abundances of nitrogen, oxygen, neon, sulphur and argon, relative to hydrogen. We also determined helium temperatures and ionic abundances of helium and carbon from the optical recombination lines. We obtained a good fit to the observations for most of the emission-line fluxes in our photoionization model. The ionic abundances deduced from our model are in decent agreement with those derived by the empirical analysis. However, we notice obvious discrepancies between helium temperatures derived from the model and the empirical analysis, as overestimated by our model. This could be due to the presence of a small fraction of cold metal-rich structures, which were not included in our model. It is found that the observed nebular line fluxes were best reproduced by using a hydrogen-deficient expanding model atmosphere as the ionizing source with an effective temperature of T-eff = 70 kK and a stellar luminosity of L-star = 5500 L-circle dot, which corresponds to a relatively low-mass progenitor star (similar to 3 M-circle dot) rather than a massive Pop I star.
KW  - stars: Wolf-Rayet
KW  - ISM: abundances
KW  - planetary nebulae: individual: Abell 48
Y1  - 2014
U6  - https://doi.org/10.1093/mnras/stu203
SN  - 0035-8711
SN  - 1365-2966
VL  - 439
IS  - 4
SP  - 3605
EP  - 3615
PB  - Oxford Univ. Press
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Mizuno, Yosuke
A1  - Pohl, Martin
A1  - Niemiec, Jacek
A1  - Zhang, Bing
A1  - Nishikawa, Ken-Ichi
A1  - Hardee, Philip E.
T1  - Magnetic field amplification and saturation in turbulence behind a relativistic shock
JF  - Monthly notices of the Royal Astronomical Society
N2  - We have investigated via 2D relativistic magnetohydrodynamic simulations the long-term evolution of turbulence created by a relativistic shock propagating through an inhomogeneous medium. In the post-shock region, magnetic field is strongly amplified by turbulent motions triggered by pre-shock density inhomogeneities. Using a long-simulation box we have followed the magnetic field amplification until it is fully developed and saturated. The turbulent velocity is subrelativistic even for a strong shock. Magnetic field amplification is controlled by the turbulent motion and saturation occurs when the magnetic energy is comparable to the turbulent kinetic energy. Magnetic field amplification and saturation depend on the initial strength and direction of the magnetic field in the pre-shock medium, and on the shock strength. If the initial magnetic field is perpendicular to the shock normal, the magnetic field is first compressed at the shock and then can be amplified by turbulent motion in the post-shock region. Saturation occurs when the magnetic energy becomes comparable to the turbulent kinetic energy in the post-shock region. If the initial magnetic field in the pre-shock medium is strong, the post-shock region becomes turbulent but significant field amplification does not occur. If the magnetic energy after shock compression is larger than the turbulent kinetic energy in the post-shock region, significant field amplification does not occur. We discuss possible applications of our results to gamma-ray bursts and active galactic nuclei.
KW  - MHD
KW  - relativistic processes
KW  - shock waves
KW  - turbulence
KW  - methods: numerical
KW  - gamma-ray burst: general
Y1  - 2014
U6  - https://doi.org/10.1093/mnras/stu196
SN  - 0035-8711
SN  - 1365-2966
VL  - 439
IS  - 4
SP  - 3490
EP  - 3503
PB  - Oxford Univ. Press
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Abramowski, Attila
A1  - Aharonian, Felix A.
A1  - Benkhali, Faical  Ait
A1  - Akhperjanian, A. G.
A1  - Angüner, Ekrem Oǧuzhan
A1  - Anton, Gisela
A1  - Balenderan, Shangkari
A1  - Balzer, Arnim
A1  - Barnacka, Anna
A1  - Becherini, Yvonne
A1  - Tjus, J. Becker
A1  - Bernlöhr, K.
A1  - Birsin, E.
A1  - Bissaldi, E.
A1  - Biteau, Jonathan
A1  - Boettcher, Markus
A1  - Boisson, Catherine
A1  - Bolmont, J.
A1  - Bordas, Pol
A1  - Brucker, J.
A1  - Brun, Francois
A1  - Brun, Pierre
A1  - Bulik, Tomasz
A1  - Carrigan, Svenja
A1  - Casanova, Sabrina
A1  - Cerruti, M.
A1  - Chadwick, Paula M.
A1  - Chalme-Calvet, R.
A1  - Chaves, Ryan C. G.
A1  - Cheesebrough, A.
A1  - Chretien, M.
A1  - Colafrancesco, Sergio
A1  - Cologna, Gabriele
A1  - Conrad, Jan
A1  - Couturier, C.
A1  - Cui, Y.
A1  - Dalton, M.
A1  - Daniel, Michael K.
A1  - Davids, I. D.
A1  - Degrange, B.
A1  - Deil, C.
A1  - deWilt, P.
A1  - Dickinson, H. J.
A1  - Djannati-Ataï, A.
A1  - Domainko, W.
A1  - Dubus, G.
A1  - Dutson, K.
A1  - Dyks, J.
A1  - Dyrda, M.
A1  - Edwards, T.
A1  - Egberts, Kathrin
A1  - Eger, P.
A1  - Espigat, P.
A1  - Farnier, C.
A1  - Fegan, S.
A1  - Feinstein, F.
A1  - Fernandes, M. V.
A1  - Fernandez, D.
A1  - Fiasson, A.
A1  - Fontaine, G.
A1  - Foerster, A.
A1  - Fuessling, M.
A1  - Gajdus, M.
A1  - Gallant, Y. A.
A1  - Garrigoux, T.
A1  - Giavitto, G.
A1  - Giebels, B.
A1  - Glicenstein, J. F.
A1  - Grondin, M. -H.
A1  - Grudzinska, M.
A1  - Haeffner, S.
A1  - Hahn, J.
A1  - Harris, J.
A1  - Heinzelmann, G.
A1  - Henri, G.
A1  - Hermann, G.
A1  - Hervet, O.
A1  - Hillert, A.
A1  - Hinton, James Anthony
A1  - Hofmann, W.
A1  - Hofverberg, P.
A1  - Holler, M.
A1  - Horns, D.
A1  - Jacholkowska, A.
A1  - Jahn, C.
A1  - Jamrozy, Marek
A1  - Janiak, M.
A1  - Jankowsky, F.
A1  - Jung, I.
A1  - Kastendieck, M. A.
A1  - Katarzynski, Krzysztof
A1  - Katz, Uli
A1  - Kaufmann, S.
A1  - Khelifi, B.
A1  - Kieffer, M.
A1  - Klepser, S.
A1  - Klochkov, D.
A1  - Kluzniak, W.
A1  - Kneiske, T.
A1  - Kolitzus, D.
A1  - Komin, Nu.
A1  - Kosack, K.
A1  - Krakau, S.
A1  - Krayzel, F.
A1  - Krueger, P. P.
A1  - Laffon, H.
A1  - Lamanna, G.
A1  - Lefaucheur, J.
A1  - Lemiere, A.
A1  - Lemoine-Goumard, M.
A1  - Lenain, J. -P.
A1  - Lennarz, D.
A1  - Lohse, T.
A1  - Lopatin, A.
A1  - Lu, C. -C.
A1  - Marandon, V.
A1  - Marcowith, Alexandre
A1  - Marx, R.
A1  - Maurin, G.
A1  - Maxted, N.
A1  - Mayer, M.
A1  - McComb, T. J. L.
A1  - Mehault, J.
A1  - Meintjes, P. J.
A1  - Menzler, U.
A1  - Meyer, M.
A1  - Moderski, R.
A1  - Mohamed, M.
A1  - Moulin, Emmanuel
A1  - Murach, T.
A1  - Naumann, C. L.
A1  - de Naurois, M.
A1  - Niemiec, J.
A1  - Nolan, S. J.
A1  - Oakes, L.
A1  - Ohm, S.
A1  - Wilhelmi, E. de Ona
A1  - Opitz, B.
A1  - Ostrowski, M.
A1  - Oya, I.
A1  - Panter, M.
A1  - Parsons, R. D.
A1  - Arribas, M. Paz
A1  - Pekeur, N. W.
A1  - Pelletier, G.
A1  - Perez, J.
A1  - Petrucci, P. -O.
A1  - Peyaud, B.
A1  - Pita, S.
A1  - Poon, H.
A1  - Puehlhofer, G.
A1  - Punch, Michael
A1  - Quirrenbach, A.
A1  - Raab, S.
A1  - Raue, M.
A1  - Reimer, A.
A1  - Reimer, Olaf
A1  - Renaud, M.
A1  - de los Reyes, R.
A1  - Rieger, F.
A1  - Rob, L.
A1  - Romoli, C.
A1  - Rosier-Lees, S.
A1  - Rowell, G.
A1  - Rudak, B.
A1  - Rulten, C. B.
A1  - Sahakian, V.
A1  - Sanchez, David M.
A1  - Santangelo, Andrea
A1  - Schlickeiser, R.
A1  - Schuessler, F.
A1  - Schulz, A.
A1  - Schwanke, U.
A1  - Schwarzburg, S.
A1  - Schwemmer, S.
A1  - Sol, H.
A1  - Spengler, G.
A1  - Spies, F.
A1  - Stawarz, L.
A1  - Steenkamp, R.
A1  - Stegmann, Christian
A1  - Stinzing, F.
A1  - Stycz, K.
A1  - Sushch, Iurii
A1  - Szostek, A.
A1  - Tavernet, J. -P.
A1  - Tavernier, T.
A1  - Taylor, A. M.
A1  - Terrier, R.
A1  - Tluczykont, M.
A1  - Trichard, C.
A1  - Valerius, K.
A1  - van Eldik, Christopher
A1  - van Soelen, B.
A1  - Vasileiadis, G.
A1  - Venter, C.
A1  - Viana, A.
A1  - Vincent, P.
A1  - Vink, J.
A1  - Voelk, H. J.
A1  - Volpe, F.
A1  - Vorster, M.
A1  - Vuillaume, T.
A1  - Wagner, S. J.
A1  - Wagner, P.
A1  - Ward, M.
A1  - Weidinger, M.
A1  - Weitzel, Q.
A1  - White, R.
A1  - Wierzcholska, A.
A1  - Willmann, P.
A1  - Woernlein, A.
A1  - Wouters, D.
A1  - Zabalza, V.
A1  - Zacharias, M.
A1  - Zajczyk, A.
A1  - Zdziarski, A. A.
A1  - Zech, Alraune
A1  - Zechlin, H. -S.
T1  - HESS J1640-465-an exceptionally luminous TeV gamma-ray supernova remnant
JF  - Monthly notices of the Royal Astronomical Society
N2  - The results of follow-up observations of the TeV gamma-ray source HESS J1640-465 from 2004 to 2011 with the High Energy Stereoscopic System (HESS) are reported in this work. The spectrum is well described by an exponential cut-off power law with photon index Gamma = 2.11 +/- 0.09(stat) +/- 0.10(sys), and a cut-off energy of E-2 = 6.0(-1.2)(+2.0) TeV. The TeV emission is significantly extended and overlaps with the northwestern part of the shell of the SNR G338.3-0.0. The new HESS results, a re-analysis of archival XMM-Newton data and multiwavelength observations suggest that a significant part of the gamma-ray emission from HESS J1640-465 originates in the supernova remnant shell. In a hadronic scenario, as suggested by the smooth connection of the GeV and TeV spectra, the product of total proton energy and mean target density could be as high as W(p)n(H) similar to 4 x 10(52)(d/10kpc)(2) erg cm(-3).
KW  - radiation mechanisms: non-thermal
KW  - ISM: individual objects: G338.3-0.0
KW  - ISM: supernova remnants
Y1  - 2014
U6  - https://doi.org/10.1093/mnras/stu139
SN  - 0035-8711
SN  - 1365-2966
VL  - 439
IS  - 3
SP  - 2828
EP  - 2836
PB  - Oxford Univ. Press
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Albrecht, Steve
A1  - Tumbleston, John R.
A1  - Janietz, Silvia
A1  - Dumsch, Ines
A1  - Allard, Sybille
A1  - Scherf, Ullrich
A1  - Ade, Harald W.
A1  - Neher, Dieter
T1  - Quantifying charge extraction in organic solar cells: The case of fluorinated PCPDTBT
JF  - The journal of physical chemistry letters
N2  - We introduce a new and simple method to quantify the effective extraction mobility in organic solar cells at low electric fields and charge carrier densities comparable to operation conditions under one sun illumination. By comparing steady-state carrier densities at constant illumination intensity and under open-circuit conditions, the gradient of the quasi-Fermi potential driving the current is estimated as a function of external bias and charge density. These properties are then related to the respective steady-state current to determine the effective extraction mobility. The new technique is applied to different derivatives of the well-known low-band-gap polymer PCPDTBT blended with PC70BM. We show that the slower average extraction due to lower mobility accounts for the moderate fill factor when solar cells are fabricated with mono- or difluorinated PCPDTBT. This lower extraction competes with improved generation and reduced nongeminate recombination, rendering the monofluorinated derivative the most efficient donor polymer.
Y1  - 2014
U6  - https://doi.org/10.1021/jz500457b
SN  - 1948-7185
VL  - 5
IS  - 7
SP  - 1131
EP  - 1138
PB  - American Chemical Society
CY  - Washington
ER  - 
TY  - JOUR
A1  - Shin, Jaeoh
A1  - Cherstvy, Andrey G.
A1  - Metzler, Ralf
T1  - Sensing viruses by mechanical tension of DNA in responsive hydrogels
JF  - Physical review : X, Expanding access
N2  - The rapid worldwide spread of severe viral infections, often involving novel mutations of viruses, poses major challenges to our health-care systems. This means that tools that can efficiently and specifically diagnose viruses are much needed. To be relevant for broad applications in local health-care centers, such tools should be relatively cheap and easy to use. In this paper, we discuss the biophysical potential for the macroscopic detection of viruses based on the induction of a mechanical stress in a bundle of prestretched DNA molecules upon binding of viruses to the DNA. We show that the affinity of the DNA to the charged virus surface induces a local melting of the double helix into two single-stranded DNA. This process effects a mechanical stress along the DNA chains leading to an overall contraction of the DNA. Our results suggest that when such DNA bundles are incorporated in a supporting matrix such as a responsive hydrogel, the presence of viruses may indeed lead to a significant, macroscopic mechanical deformation of the matrix. We discuss the biophysical basis for this effect and characterize the physical properties of the associated DNA melting transition. In particular, we reveal several scaling relations between the relevant physical parameters of the system. We promote this DNA-based assay as a possible tool for efficient and specific virus screening.
Y1  - 2014
U6  - https://doi.org/10.1103/PhysRevX.4.021002
SN  - 2160-3308
VL  - 4
IS  - 2
PB  - American Physical Society
CY  - College Park
ER  - 
TY  - JOUR
A1  - Pollatos, Olga
A1  - Yeldesbay, Azamat
A1  - Pikovskij, Arkadij
A1  - Rosenblum, Michael
T1  - How much time has passed? Ask your heart
JF  - Frontiers in neurorobotics
N2  - Internal signals like one's heartbeats are centrally processed via specific pathways and both their neural representations as well as their conscious perception (interoception) provide key information for many cognitive processes. Recent empirical findings propose that neural processes in the insular cortex, which are related to bodily signals, might constitute a neurophysiological mechanism for the encoding of duration. Nevertheless, the exact nature of such a proposed relationship remains unclear. We aimed to address this question by searching for the effects of cardiac rhythm on time perception by the use of a duration reproduction paradigm. Time intervals used were of 0.5, 2, 3, 7, 10, 14, 25, and 40s length. In a framework of synchronization hypothesis, measures of phase locking between the cardiac cycle and start/stop signals of the reproduction task were calculated to quantify this relationship. The main result is that marginally significant synchronization indices (Sls) between the heart cycle and the time reproduction responses for the time intervals of 2, 3, 10, 14, and 25s length were obtained, while results were not significant for durations of 0.5, 7, and 40s length. On the single participant level, several subjects exhibited some synchrony between the heart cycle and the time reproduction responses, most pronounced for the time interval of 25s (8 out of 23 participants for 20% quantile). Better time reproduction accuracy was not related with larger degree of phase locking, but with greater vagal control of the heart. A higher interoceptive sensitivity (IS) was associated with a higher synchronization index (SI) for the 2s time interval only. We conclude that information obtained from the cardiac cycle is relevant for the encoding and reproduction of time in the time span of 2-25s. Sympathovagal tone as well as interoceptive processes mediate the accuracy of time estimation.
KW  - time interval reproduction
KW  - synchronization
KW  - heart cycle
KW  - interoception
KW  - interoceptive sensitivity
Y1  - 2014
U6  - https://doi.org/10.3389/fnbot.2014.00015
SN  - 1662-5218
VL  - 8
SP  - 1
EP  - 9
PB  - Frontiers Research Foundation
CY  - Lausanne
ER  - 
TY  - JOUR
A1  - Archambault, S.
A1  - Aune, T.
A1  - Behera, B.
A1  - Beilicke, M.
A1  - Benbow, W.
A1  - Berger, K.
A1  - Bird, R.
A1  - Biteau, Jonathan
A1  - Bugaev, V.
A1  - Byrum, K.
A1  - Cardenzana, J. V.
A1  - Cerruti, M.
A1  - Chen, Xuhui
A1  - Ciupik, L.
A1  - Connolly, M. P.
A1  - Cui, Wei
A1  - Dumm, J.
A1  - Errando, M.
A1  - Falcone, A.
A1  - Federici, Simone
A1  - Feng, Q.
A1  - Finley, J. P.
A1  - Fleischhack, H.
A1  - Fortson, L.
A1  - Furniss, A.
A1  - Galante, N.
A1  - Gillanders, G. H.
A1  - Griffin, S.
A1  - Griffiths, S. T.
A1  - Grube, J.
A1  - Gyuk, G.
A1  - Hanna, D.
A1  - Holder, J.
A1  - Hughes, G.
A1  - Humensky, T. B.
A1  - Johnson, C. A.
A1  - Kaaret, P.
A1  - Kertzman, M.
A1  - Khassen, Y.
A1  - Kieda, D.
A1  - Krawczynski, H.
A1  - Krennrich, F.
A1  - Kumar, S.
A1  - Lang, M. J.
A1  - Madhavan, A. S.
A1  - Maier, G.
A1  - McCann, A.
A1  - Meagher, K.
A1  - Moriarty, P.
A1  - Mukherjee, R.
A1  - Nieto, Daniel
A1  - Ong, R. A.
A1  - Otte, A. N.
A1  - Park, N.
A1  - Pohl, Martin
A1  - Popkow, A.
A1  - Prokoph, H.
A1  - Quinn, J.
A1  - Ragan, K.
A1  - Rajotte, J.
A1  - Reyes, L. C.
A1  - Reynolds, P. T.
A1  - Richards, G. T.
A1  - Roache, E.
A1  - Sembroski, G. H.
A1  - Shahinyan, K.
A1  - Staszak, D.
A1  - Telezhinsky, Igor O.
A1  - Tucci, J. V.
A1  - Tyler, J.
A1  - Varlotta, A.
A1  - Vassiliev, V. V.
A1  - Vincent, S.
A1  - Wakely, S. P.
A1  - Weinstein, A.
A1  - Welsing, R.
A1  - Wilhelm, Alina
A1  - Williams, D. A.
A1  - Ackermann, Margit
A1  - Ajello, M.
A1  - Albert, A.
A1  - Baldini, L.
A1  - Bastieri, D.
A1  - Bellazzini, R.
A1  - Bissaldi, E.
A1  - Bregeon, Johan
A1  - Buehler, R.
A1  - Buson, S.
A1  - Caliandro, G. A.
A1  - Cameron, R. A.
A1  - Caraveo, P. A.
A1  - Cavazzuti, E.
A1  - Charles, E.
A1  - Chiang, J.
A1  - Ciprini, S.
A1  - Claus, R.
A1  - Cutini, S.
A1  - de Angelis, A.
A1  - de Palma, F.
A1  - Dermer, C. D.
A1  - Digel, S. W.
A1  - Di Venere, L.
A1  - Drell, P. S.
A1  - Favuzzi, C.
A1  - Franckowiak, A.
A1  - Fusco, P.
A1  - Gargano, F.
A1  - Gasparrini, D.
A1  - Giglietto, N.
A1  - Giordano, F.
A1  - Giroletti, M.
A1  - Grenier, I. A.
A1  - Guiriec, S.
A1  - Jogler, T.
A1  - Kuss, M.
A1  - Larsson, S.
A1  - Latronico, L.
A1  - Longo, F.
A1  - Loparco, F.
A1  - Lubrano, P.
A1  - Madejski, G. M.
A1  - Mayer, M.
A1  - Mazziotta, Mario Nicola
A1  - Michelson, P. F.
A1  - Mizuno, T.
A1  - Monzani, M. E.
A1  - Morselli, Aldo
A1  - Murgia, S.
A1  - Nuss, E.
A1  - Ohsugi, T.
A1  - Ormes, J. F.
A1  - Paneque, D.
A1  - Perkins, J. S.
A1  - Piron, F.
A1  - Pivato, G.
A1  - Raino, S.
A1  - Razzano, M.
A1  - Reimer, A.
A1  - Reimer, Olaf
A1  - Ritz, S.
A1  - Schaal, M.
A1  - Sgro, C.
A1  - Siskind, E. J.
A1  - Spinelli, P.
A1  - Takahashi, H.
A1  - Tibaldo, L.
A1  - Tinivella, M.
A1  - Troja, E.
A1  - Vianello, G.
A1  - Werner, M.
A1  - Wood, M.
T1  - Deep broadband observations of the distant gamma-ray blazar PKS 1424+240
JF  - The astrophysical journal : an international review of spectroscopy and astronomical physics ; Part 2, Letters
N2  - We present deep VERITAS observations of the blazar PKS 1424+240, along with contemporaneous Fermi Large Area Telescope, Swift X-ray Telescope, and Swift UV Optical Telescope data between 2009 February 19 and 2013 June 8. This blazar resides at a redshift of z >= 0.6035, displaying a significantly attenuated gamma-ray flux above 100 GeV due to photon absorption via pair-production with the extragalactic background light. We present more than 100 hr of VERITAS observations over three years, a multiwavelength light curve, and the contemporaneous spectral energy distributions. The source shows a higher flux of (2.1 +/- 0.3) x 10(-7) photons m(-2) s(-1) above 120 GeV in 2009 and 2011 as compared to the flux measured in 2013, corresponding to (1.02 +/- 0.08) x 10-7 photons m(-2) s(-1) above 120 GeV. The measured differential very high energy (VHE; E >= 100 GeV) spectral indices are Gamma = 3.8 +/- 0.3, 4.3 +/- 0.6 and 4.5 +/- 0.2 in 2009, 2011, and 2013, respectively. No significant spectral change across the observation epochs is detected. We find no evidence for variability at gamma-ray opacities of greater than tau = 2, where it is postulated that any variability would be small and occur on timescales longer than a year if hadronic cosmic-ray interactions with extragalactic photon fields provide a secondary VHE photon flux. The data cannot rule out such variability due to low statistics.
KW  - BL Lacertae objects: individual (PKS 1424+240)-cosmic background radiation
KW  - gamma rays: galaxies
Y1  - 2014
U6  - https://doi.org/10.1088/2041-8205/785/1/L16
SN  - 2041-8205
SN  - 2041-8213
VL  - 785
IS  - 1
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  - 
TY  - JOUR
A1  - Yeldesbay, Azamat
A1  - Pikovskij, Arkadij
A1  - Rosenblum, Michael
T1  - Chimeralike states in an ensemble of globally coupled oscillators
JF  - Physical review letters
N2  - We demonstrate the emergence of a complex state in a homogeneous ensemble of globally coupled identical oscillators, reminiscent of chimera states in nonlocally coupled oscillator lattices. In this regime some part of the ensemble forms a regularly evolving cluster, while all other units irregularly oscillate and remain asynchronous. We argue that the chimera emerges because of effective bistability, which dynamically appears in the originally monostable system due to internal delayed feedback in individual units. Additionally, we present two examples of chimeras in bistable systems with frequency-dependent phase shift in the global coupling.
Y1  - 2014
U6  - https://doi.org/10.1103/PhysRevLett.112.144103
SN  - 0031-9007
SN  - 1079-7114
VL  - 112
IS  - 14
PB  - American Physical Society
CY  - College Park
ER  - 
TY  - GEN
A1  - Talukder, Srijeeta
A1  - Sen, Shrabani
A1  - Chakraborti, Prantik
A1  - Metzler, Ralf
A1  - Banik, Suman K.
A1  - Chaudhury, Pinaki
T1  - Breathing dynamics based parameter sensitivity analysis of hetero-polymeric DNA
T2  - The journal of chemical physics : bridges a gap between journals of physics and journals of chemistr
N2  - We study the parameter sensitivity of hetero-polymeric DNA within the purview of DNA breathing dynamics. The degree of correlation between the mean bubble size and the model parameters is estimated for this purpose for three different DNA sequences. The analysis leads us to a better understanding of the sequence dependent nature of the breathing dynamics of hetero-polymeric DNA. Out of the 14 model parameters for DNA stability in the statistical Poland-Scheraga approach, the hydrogen bond interaction epsilon(hb)(AT) for an AT base pair and the ring factor. turn out to be the most sensitive parameters. In addition, the stacking interaction epsilon(st)(TA-TA) for an TA-TA nearest neighbor pair of base-pairs is found to be the most sensitive one among all stacking interactions. Moreover, we also establish that the nature of stacking interaction has a deciding effect on the DNA breathing dynamics, not the number of times a particular stacking interaction appears in a sequence. We show that the sensitivity analysis can be used as an effective measure to guide a stochastic optimization technique to find the kinetic rate constants related to the dynamics as opposed to the case where the rate constants are measured using the conventional unbiased way of optimization.
Y1  - 2014
U6  - https://doi.org/10.1063/1.4871297
SN  - 0021-9606
SN  - 1089-7690
VL  - 140
IS  - 14
PB  - American Institute of Physics
CY  - Melville
ER  - 
TY  - JOUR
A1  - Shalom, Menny
A1  - Inal, Sahika
A1  - Neher, Dieter
A1  - Antonietti, Markus
T1  - SiO2/carbon nitride composite materials: The role of surfaces for enhanced photocatalysis
JF  - Catalysis today : a serial publication dealing with topical themes in catalysis and related subjects
N2  - The effect of SiO2 nanoparticles on carbon nitride (C3N4) photoactivity performance is described. The composite SiO2-C3N4 materials exhibit a higher activity in the photo degradation of RhB dye. A detailed analysis of the chemical and optical properties of the composite C3N4 materials shows that the photo activity increases with higher SiO2 concentration. We found out that the presence of SiO2 nanoparticles strongly affects the fluorescence intensity of the matrix and life time by the creation of new energy states for charge transfer within the C3N4. Furthermore, the use of SiO2 in the synthesis of C3N4 leads to new morphology with higher surface area which results in another, secondary improvement of C3N4 photoactivity. The effect of different surfaces within C3N4 on its chemical and electronic properties is discussed and a tentative mechanism is proposed. The utilization of SiO2 nanoparticles improves both photophysical and chemical properties of C3N4 and opens new possibilities for further enhancement of C3N4 catalytic properties by the formation of composites with many other materials.
KW  - Carbon nitride
KW  - SiO2 composite material
KW  - Photocatalysis
KW  - RhB degradation
Y1  - 2014
U6  - https://doi.org/10.1016/j.cattod.2013.12.013
SN  - 0920-5861
SN  - 1873-4308
VL  - 225
SP  - 185
EP  - 190
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Harris, Scott
A1  - Mellinger, Axel
T1  - Towards a better understanding of dielectric barrier discharges in ferroelectrets: Paschen breakdown fields in micrometer sized voids
JF  - Journal of applied physics
N2  - Charged cellular polypropylene foams (i.e., ferro-or piezoelectrets) demonstrate high piezoelectric activity upon being electrically charged. When an external electric field is applied, dielectric barrier discharges (DBDs) occur, resulting in a separation of charges which are subsequently deposited on dielectric surfaces of internal micrometer sized voids. This deposited space charge is responsible for the piezoelectric activity of the material. Previous studies have indicated charging fields larger than predicted by Townsend's model of Paschen breakdown applied to a multilayered electromechanical model; a discrepancy which prompted the present study. The actual breakdown fields for micrometer sized voids were determined by constructing single cell voids using polypropylene spacers with heights ranging from 8 to 75 mu m, "sandwiched" between two polypropylene dielectric barriers and glass slides with semi-transparent electrodes. Subsequently, a bipolar triangular charging waveform with a peak voltage of 6 kV was applied to the samples. The breakdown fields were determined by monitoring the emission of light due to the onset of DBDs using an electron multiplying CCD camera. The breakdown fields at absolute pressures from 101 to 251 kPa were found to be in good agreement with the standard Paschen curves. Additionally, the magnitude of the light emission was found to scale linearly with the amount of gas, i.e., the height of the voids. Emissions were homogeneous over the observed regions of the voids for voids with heights of 25 lm or less and increasingly inhomogeneous for void heights greater than 40 lm at high electric fields.
Y1  - 2014
U6  - https://doi.org/10.1063/1.4871678
SN  - 0021-8979
SN  - 1089-7550
VL  - 115
IS  - 16
PB  - American Institute of Physics
CY  - Melville
ER  - 
TY  - JOUR
A1  - Krüsemann, Henning
A1  - Godec, Aljaz
A1  - Metzler, Ralf
T1  - First-passage statistics for aging diffusion in systems with annealed and quenched disorder
JF  - Physical review : E, Statistical, nonlinear and soft matter physics
N2  - Aging, the dependence of the dynamics of a physical process on the time t(a) since its original preparation, is observed in systems ranging from the motion of charge carriers in amorphous semiconductors over the blinking dynamics of quantum dots to the tracer dispersion in living biological cells. Here we study the effects of aging on one of the most fundamental properties of a stochastic process, the first-passage dynamics. We find that for an aging continuous time random walk process, the scaling exponent of the density of first-passage times changes twice as the aging progresses and reveals an intermediate scaling regime. The first-passage dynamics depends on t(a) differently for intermediate and strong aging. Similar crossovers are obtained for the first-passage dynamics for a confined and driven particle. Comparison to the motion of an aged particle in the quenched trap model with a bias shows excellent agreement with our analytical findings. Our results demonstrate how first-passage measurements can be used to unravel the age t(a) of a physical system.
Y1  - 2014
U6  - https://doi.org/10.1103/PhysRevE.89.040101
SN  - 1539-3755
SN  - 1550-2376
VL  - 89
IS  - 4
PB  - American Physical Society
CY  - College Park
ER  - 
TY  - JOUR
A1  - Albrecht, Torsten
A1  - Levermann, Anders
T1  - Spontaneous ice-front retreat caused by disintegration of adjacent ice shelf in Antarctica
JF  - Earth & planetary science letters
N2  - Antarctic ice-discharge constitutes the largest uncertainty in future sea-level projections. Floating ice shelves, fringing most of Antarctica, exert retentive forces onto the ice flow. While abrupt ice-shelf retreat has been observed, it is generally considered a localized phenomenon. Here we show that the disintegration of an ice shelf may induce the spontaneous retreat of its neighbor. As an example, we reproduce the spontaneous but gradual retreat of the Larsen B ice front as observed after the disintegration of the adjacent Larsen A ice shelf. We show that the Larsen A collapse yields a change in spreading rate in Larsen B via their connecting ice channels and thereby causes a retreat of the ice front to its observed position of the year 2000, prior to its collapse. This mechanism might be particularly relevant for the role of East Antarctica and the Antarctic Peninsula in future sea level.
KW  - Antarctica
KW  - Larsen Ice Shelf
KW  - glaciology
KW  - numerical ice modeling
KW  - sea level
KW  - iceberg calving
Y1  - 2014
U6  - https://doi.org/10.1016/j.epsl.2014.02.034
SN  - 0012-821X
SN  - 1385-013X
VL  - 393
SP  - 26
EP  - 30
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Cherstvy, Andrey G.
T1  - Electrostatics and charge regulation in polyelectrolyte multi layered assembly
JF  - The journal of physical chemistry : B, Condensed matter, materials, surfaces, interfaces & biophysical chemistry
N2  - We examine the implications of electrostatic interactions on formation of polyelectrolyte multilayers, in application to field-effect based biosensors for label-free detection of charged macromolecules. We present a quantitative model to describe the experimental potentiometric observations and discuss its possibilities and limitations for detection of polyelectrolyte adsorption. We examine the influence of the ionic strength and pH on the sensor response upon polyelectrolyte layer-by-layer formation. The magnitude of potential oscillations on the sensor-electrolyte interface predicted upon repetitive adsorption charge-alternating polymers agrees satisfactorily with experimental results. The model accounts for different screening by mobile ions in electrolyte and inside tightly interdigitated multilayered structure. In particular, we show that sensors' potential oscillations are larger and more persistent at lower salt conditions, while they decay faster with the number of layers at higher salt conditions, in agreement with experiments. The effects of polyelectrolyte layer thickness, substrate potential, and charge regulation on the sensor surface triggered by layer-by-layer deposition are also analyzed.
Y1  - 2014
U6  - https://doi.org/10.1021/jp502460v
SN  - 1520-6106
VL  - 118
IS  - 17
SP  - 4552
EP  - 4560
PB  - American Chemical Society
CY  - Washington
ER  - 
TY  - JOUR
A1  - Pradhan, Basudev
A1  - Albrecht, Steve
A1  - Stiller, Burkhard
A1  - Neher, Dieter
T1  - Inverted organic solar cells comprising low-temperature-processed ZnO films
JF  - Applied physics : A, Materials science & processing
N2  - Inverted organic solar cells are fabricated using low-temperature-annealed ZnO film as an electron transport layer. Uniform ZnO films were prepared by spin coating a diethylzinc (DEZ) precursor solution in air, followed by annealing at 100 A degrees C. Organic solar cells prepared on these ZnO films with a 1:1 P3HT:PCBM blend as the active layer show a high power conversion efficiency of 4.03 %, which is more than 10 % higher than the PCE of solar cells comprising ZnO prepared via a high-temperature sol-gel route.
Y1  - 2014
U6  - https://doi.org/10.1007/s00339-014-8373-8
SN  - 0947-8396
SN  - 1432-0630
VL  - 115
IS  - 2
SP  - 365
EP  - 369
PB  - Springer
CY  - New York
ER  - 
TY  - JOUR
A1  - Baushev, Anton N.
T1  - Galaxy halo formation in the absence of violent relaxation and a universal density profile of the halo center
JF  - The astrophysical journal : an international review of spectroscopy and astronomical physics
N2  - While N-body simulations testify to a cuspy profile of the central region of dark matter halos, observations favor a shallow, cored density profile of the central region of at least some spiral galaxies and dwarf spheroidals. We show that a central profile, very close to the observed one, inevitably forms in the center of dark matter halos if we make a supposition about a moderate energy relaxation of the system during the halo formation. If we assume the energy exchange between dark matter particles during the halo collapse is not too intensive, the profile is universal: it depends almost not at all on the properties of the initial perturbation and is very akin, but not identical, to the Einasto profile with a small Einasto index n similar to 0.5. We estimate the size of the "central core" of the distribution, i.e., the extent of the very central region with a respectively gentle profile, and show that the cusp formation is unlikely, even if the dark matter is cold. The obtained profile is in good agreement with observational data for at least some types of galaxies but clearly disagrees with N-body simulations.
KW  - astroparticle physics
KW  - dark matter
KW  - elementary particles
KW  - large-scale structure of universe
Y1  - 2014
U6  - https://doi.org/10.1088/0004-637X/786/1/65
SN  - 0004-637X
SN  - 1538-4357
VL  - 786
IS  - 1
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  - 
TY  - JOUR
A1  - Kniepert, Juliane
A1  - Lange, Ilja
A1  - van der Kaap, Niels J.
A1  - Koster, L. Jan Anton
A1  - Neher, Dieter
T1  - A conclusive view on charge generation, recombination, and extraction in As-prepared and annealed P3HT:PCBM blends: combined experimental and simulation work
JF  - dvanced energy materials
N2  - Time-delayed collection field (TDCF) and bias-amplified charge extraction (BACE) are applied to as-prepared and annealed poly(3-hexylthiophene):[6,6]-phenyl C-71 butyric acid methyl ester (P3HT:PCBM) blends coated from chloroform. Despite large differences in fill factor, short-circuit current, and power conversion efficiency, both blends exhibit a negligible dependence of photogeneration on the electric field and strictly bimolecular recombination (BMR) with a weak dependence of the BMR coefficient on charge density. Drift-diffusion simulations are performed using the measured coefficients and mobilities, taking into account bimolecular recombination and the possible effects of surface recombination. The excellent agreement between the simulation and the experimental data for an intensity range covering two orders of magnitude indicates that a field-independent generation rate and a density-independent recombination coefficient describe the current-voltage characteristics of the annealed P3HT: PCBM devices, while the performance of the as-prepared blend is shown to be limited by space charge effects due to a low hole mobility. Finally, even though the bimolecular recombination coefficient is small, surface recombination is found to be a negligible loss mechanism in these solar cells.
Y1  - 2014
U6  - https://doi.org/10.1002/aenm.201301401
SN  - 1614-6832
SN  - 1614-6840
VL  - 4
IS  - 7
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Reindl, Nicole
A1  - Rauch, Thomas
A1  - Parthasarathy, M.
A1  - Werner, K.
A1  - Kruk, J. W.
A1  - Hamann, Wolf-Rainer
A1  - Sander, Andreas Alexander Christoph
A1  - Todt, Helge Tobias
T1  - The rapid evolution of the exciting star of the Stingray nebula
JF  - Astronomy and astrophysics : an international weekly journal
N2  - Context. SAO 244567, the exciting star of the Stingray nebula, is rapidly evolving. Previous analyses suggested that it has heated up from an effective temperature of about 21 kK in 1971 to over 50 kK in the 1990s. Canonical post-asymptotic giant branch evolution suggests a relatively high mass while previous analyses indicate a low-mass star.
 Aims. A comprehensive model-atmosphere analysis of UV and optical spectra taken during 1988-2006 should reveal the detailed temporal evolution of its atmospheric parameters and provide explanations for the unusually fast evolution.
 Methods. Fitting line profiles from static and expanding non-LTE model atmospheres to the observed spectra allowed us to study the temporal change of effective temperature, surface gravity, mass-loss rate, and terminal wind velocity. In addition, we determined the chemical composition of the atmosphere.
 Results. We find that the central star has steadily increased its effective temperature from 38 kK in 1988 to a peak value of 60 kK in 2002. During the same time, the star was contracting, as concluded from an increase in surface gravity from log g = 4.8 to 6.0 and a drop in luminosity. Simultaneously, the mass-loss rate declined from log(M/M-circle dot yr(-1)) = -9.0 to -11.6 and the terminal wind velocity increased from v(infinity) = 1800 km s(-1) to 2800 km s(-1). Since around 2002, the star stopped heating and has cooled down again to 55 kK by 2006. It has a largely solar surface composition with the exception of slightly subsolar carbon, phosphorus, and sulfur. The results are discussed by considering different evolutionary scenarios.
 Conclusions. The position of SAO 244567 in the log T-eff-log g plane places the star in the region of sdO stars. By comparison with stellar-evolution calculations, we confirm that SAO 244567 must be a low-mass star (M < 0.55 M-circle dot). However, the slow evolution of the respective stellar evolutionary models is in strong contrast to the observed fast evolution and the young planetary nebula with a kinematical age of only about 1000 years. We speculate that the star could be a late He-shell flash object. Alternatively, it could be the outcome of close-binary evolution. Then SAD 244567 would be a low-mass (0.354 M-circle dot) helium pre-white dwarf after the common-envelope phase, during which the planetary nebula was ejected.
KW  - stars: abundances
KW  - stars: evolution
KW  - stars: AGB and post-AGB
KW  - stars: individual: SAO 244567
KW  - stars: fundamental parameters
KW  - planetary nebulae: individual: Stingray nebula (Henize 3-1357)
Y1  - 2014
U6  - https://doi.org/10.1051/0004-6361/201323189
SN  - 0004-6361
SN  - 1432-0746
VL  - 565
PB  - EDP Sciences
CY  - Les Ulis
ER  - 
TY  - JOUR
A1  - Hainich, Rainer
A1  - Ruehling, Ute
A1  - Todt, Helge Tobias
A1  - Oskinova, Lidia M.
A1  - Liermann, A.
A1  - Graefener, G.
A1  - Foellmi, C.
A1  - Schnurr, O.
A1  - Hamann, Wolf-Rainer
T1  - The Wolf-Rayet stars in the Large Magellanic Cloud - A comprehensive analysis of the WN class
JF  - Astronomy and astrophysics : an international weekly journal
N2  - Context. Massive stars, although being important building blocks of galaxies, are still not fully understood. This especially holds true for Wolf-Rayet (WR) stars with their strong mass loss, whose spectral analysis requires adequate model atmospheres. Aims. Following our comprehensive studies of the WR stars in the Milky Way, we now present spectroscopic analyses of almost all known WN stars in the LMC.
 Methods. For the quantitative analysis of the wind-dominated emission-line spectra, we employ the Potsdam Wolf-Rayet (PoWR) model atmosphere code. By fitting synthetic spectra to the observed spectral energy distribution and the available spectra (ultraviolet and optical), we obtain the physical properties of 107 stars.
 Results. We present the fundamental stellar and wind parameters for an almost complete sample of WN stars in the LMC. Among those stars that are putatively single, two different groups can be clearly distinguished. While 12% of our sample are more luminous than 10(6) L-circle dot and contain a significant amount of hydrogen, 88% of the WN stars, with little or no hydrogen, populate the luminosity range between log (L/L-circle dot) = 5.3 ... 5.8.
 Conclusions. While the few extremely luminous stars (log (L/L-circle dot) > 6), if indeed single stars, descended directly from the main sequence at very high initial masses, the bulk of WN stars have gone through the red-supergiant phase. According to their luminosities in the range of log (L/L-circle dot) = 5.3 ... 5.8, these stars originate from initial masses between 20 and 40 M-circle dot. This mass range is similar to the one found in the Galaxy, i.e. the expected metallicity dependence of the evolution is not seen. Current stellar evolution tracks, even when accounting for rotationally induced mixing, still partly fail to reproduce the observed ranges of luminosities and initial masses. Moreover, stellar radii are generally larger and effective temperatures correspondingly lower than predicted from stellar evolution models, probably due to subphotospheric inflation.
KW  - stars: Wolf-Rayet
KW  - Magellanic Clouds
KW  - stars: early-type
KW  - stars: atmospheres
KW  - stars: winds, outflows
KW  - stars: mass-loss
Y1  - 2014
U6  - https://doi.org/10.1051/0004-6361/201322696
SN  - 0004-6361
SN  - 1432-0746
VL  - 565
PB  - EDP Sciences
CY  - Les Ulis
ER  - 
TY  - JOUR
A1  - Abramowski, Attila
A1  - Aharonian, Felix A.
A1  - Benkhali, Faical  Ait
A1  - Akhperjanian, A. G.
A1  - Angüner, Ekrem Oǧuzhan
A1  - Anton, Gisela
A1  - Balenderan, Shangkari
A1  - Balzer, Arnim
A1  - Barnacka, Anna
A1  - Becherini, Yvonne
A1  - Tjus, J. Becker
A1  - Bernlöhr, K.
A1  - Birsin, E.
A1  - Bissaldi, E.
A1  - Biteau, Jonathan
A1  - Boettcher, Markus
A1  - Boisson, Catherine
A1  - Bolmont, J.
A1  - Bordas, Pol
A1  - Brucker, J.
A1  - Brun, Francois
A1  - Brun, Pierre
A1  - Bulik, Tomasz
A1  - Carrigan, Svenja
A1  - Casanova, Sabrina
A1  - Cerruti, M.
A1  - Chadwick, Paula M.
A1  - Chalme-Calvet, R.
A1  - Chaves, Ryan C. G.
A1  - Cheesebrough, A.
A1  - Chretien, M.
A1  - Colafrancesco, Sergio
A1  - Cologna, Gabriele
A1  - Conrad, Jan
A1  - Couturier, C.
A1  - Dalton, M.
A1  - Daniel, M. K.
A1  - Davids, I. D.
A1  - Degrange, B.
A1  - Deil, C.
A1  - deWilt, P.
A1  - Dicldnson, H. J.
A1  - Djannati-Ataï, A.
A1  - Domainko, W.
A1  - Dubus, G.
A1  - Dutson, K.
A1  - Dyks, J.
A1  - Dyrda, M.
A1  - Edwards, T.
A1  - Egberts, Kathrin
A1  - Eger, P.
A1  - Espigat, P.
A1  - Farnier, C.
A1  - Fegan, S.
A1  - Feinstein, F.
A1  - Fernandes, M. V.
A1  - Fernandez, D.
A1  - Fiasson, A.
A1  - Fontaine, G.
A1  - Foerster, A.
A1  - Fuessling, Matthias
A1  - Gajdus, M.
A1  - Gallant, Y. A.
A1  - Garrigoux, T.
A1  - Giebels, B.
A1  - Glicenstein, J. F.
A1  - Grondin, M-H
A1  - Grudzinska, M.
A1  - Haeffner, S.
A1  - Hahn, J.
A1  - Harris, J.
A1  - Heinzelmann, G.
A1  - Henri, G.
A1  - Hermann, G.
A1  - Hervet, O.
A1  - Hillert, A.
A1  - Hinton, James Anthony
A1  - Hofmann, W.
A1  - Hofverberg, P.
A1  - Holler, Markus
A1  - Horns, D.
A1  - Jacholkowska, A.
A1  - Jahn, C.
A1  - Jamrozy, M.
A1  - Janiak, M.
A1  - Jankowsky, F.
A1  - Jung, I.
A1  - Kastendieck, M. A.
A1  - Katarzynski, K.
A1  - Katz, U.
A1  - Kaufmann, S.
A1  - Khelifi, B.
A1  - Kieffer, M.
A1  - Klepser, S.
A1  - Klochkov, D.
A1  - Kluzniak, W.
A1  - Kneiske, T.
A1  - Kolitzus, D.
A1  - Komin, Nu
A1  - Kosack, K.
A1  - Krakau, S.
A1  - Krayzel, F.
A1  - Krueger, P. P.
A1  - Laffon, H.
A1  - Lamanna, G.
A1  - Lefaucheur, J.
A1  - Lemiere, A.
A1  - Lemoine-Goumard, M.
A1  - Lenain, J-P
A1  - Lennarz, D.
A1  - Lohse, T.
A1  - Lopatin, A.
A1  - Lu, C-C
A1  - Marandon, V.
A1  - Marcowith, Alexandre
A1  - Marx, R.
A1  - Maurin, G.
A1  - Maxted, N.
A1  - Mayer, M.
A1  - McComb, T. J. L.
A1  - Mehault, J.
A1  - Menzler, U.
A1  - Meyer, M.
A1  - Moderski, R.
A1  - Mohamed, M.
A1  - Moulin, Emmanuel
A1  - Murach, T.
A1  - Naumann, C. L.
A1  - de Naurois, M.
A1  - Niemiec, J.
A1  - Nolan, S. J.
A1  - Oakes, L.
A1  - Ohm, S.
A1  - Wilhelmi, E. de Ona
A1  - Opitz, B.
A1  - Ostrowski, M.
A1  - Oya, I.
A1  - Panter, M.
A1  - Parsons, R. D.
A1  - Arribas, M. Paz
A1  - Pekeur, N. W.
A1  - Pelletier, G.
A1  - Perez, J.
A1  - Petrucci, P-O
A1  - Peyaud, B.
A1  - Pita, S.
A1  - Poon, H.
A1  - Puehlhofer, G.
A1  - Punch, M.
A1  - Quirrenbach, A.
A1  - Raab, S.
A1  - Raue, M.
A1  - Reimer, A.
A1  - Reimer, O.
A1  - Renaud, M.
A1  - de los Reyes, R.
A1  - Rieger, F.
A1  - Rob, L.
A1  - Romoli, C.
A1  - Rosier-Lees, S.
A1  - Rowell, G.
A1  - Rudak, B.
A1  - Rulten, C. B.
A1  - Sahakian, V.
A1  - Sanchez, David M.
A1  - Santangelo, Andrea
A1  - Schlickeiser, R.
A1  - Schuessler, F.
A1  - Schulz, A.
A1  - Schwanke, U.
A1  - Schwarzburg, S.
A1  - Schwemmer, S.
A1  - Sol, H.
A1  - Spengler, G.
A1  - Spies, F.
A1  - Stawarz, L.
A1  - Steenkamp, R.
A1  - Stegmann, Christian
A1  - Stinzing, F.
A1  - Stycz, K.
A1  - Sushch, Iurii
A1  - Szostek, A.
A1  - Tam, P. H. T.
A1  - Tavernet, J-P
A1  - Tavernier, T.
A1  - Taylor, A. M.
A1  - Terrier, R.
A1  - Tluczykont, M.
A1  - Trichard, C.
A1  - Valerius, K.
A1  - van Eldik, C.
A1  - Vasileiadis, G.
A1  - Venter, C.
A1  - Viana, A.
A1  - Vincent, P.
A1  - Voelk, H. J.
A1  - Volpe, F.
A1  - Vorster, M.
A1  - Wagner, S. J.
A1  - Wagner, P.
A1  - Ward, M.
A1  - Weidinger, M.
A1  - Weitzel, Q.
A1  - White, R.
A1  - Wierzcholska, A.
A1  - Willmann, P.
A1  - Woernlein, A.
A1  - Wouters, D.
A1  - Zacharias, M.
A1  - Zajczyk, A.
A1  - Zdziarski, A. A.
A1  - Zech, Alraune
A1  - Zechlin, H-S
T1  - Search for TeV Gamma-ray emission from GRB 100621A, an extremely bright GRB in X-rays, with HESS
JF  - Astronomy and astrophysics : an international weekly journal
N2  - The long gamma-ray burst (GRB) 100621A, at the time the brightest X-ray transient ever detected by Swift-XRT in the 0.3-10 keV range, has been observed with the H.E.S.S. imaging air Cherenkov telescope array, sensitive to gamma radiation in the very-high-energy (VHE, >100 GeV) regime. Due to its relatively small redshift of z similar to 0.5, the favourable position in the southern sky and the relatively short follow-up time (<700 s after the satellite trigger) of the H.E.S.S. observations, this GRB could be within the sensitivity reach of the HESS. instrument. The analysis of the HESS. data shows no indication of emission and yields an integral flux upper limit above similar to 380 GeV of 4.2 x 10(-12) cm(-2) s(-1) s (95% confidence level), assuming a simple Band function extension model. A comparison to a spectral-temporal model, normalised to the prompt flux at sub-MeV energies, constraints the existence of a temporally extended and strong additional hard power law, as has been observed in the other bright X-ray GRB 130427A. A comparison between the HESS. upper limit and the contemporaneous energy output in X-rays constrains the ratio between the X-ray and VHE gamma-ray fluxes to be greater than 0.4. This value is an important quantity for modelling the afterglow and can constrain leptonic emission scenarios, where leptons are responsible for the X-ray emission and might produce VHE gamma rays.
KW  - gamma rays: general
KW  - gamma-ray burst: individual: GRB 100621A
KW  - gamma rays: stars
KW  - X-rays: stars
Y1  - 2014
U6  - https://doi.org/10.1051/0004-6361/201322984
SN  - 0004-6361
SN  - 1432-0746
VL  - 565
PB  - EDP Sciences
CY  - Les Ulis
ER  - 
TY  - JOUR
A1  - Holldack, Karsten
A1  - Ovsyannikov, Ruslan
A1  - Kuske, P.
A1  - Mueller, R.
A1  - Schaelicke, A.
A1  - Scheer, M.
A1  - Gorgoi, Mihaela
A1  - Kuehn, D.
A1  - Leitner, T.
A1  - Svensson, S.
A1  - Martensson, N.
A1  - Föhlisch, Alexander
T1  - Single bunch X-ray pulses on demand from a multi-bunch synchrotron radiation source
JF  - Nature Communications
N2  - Synchrotron radiation facilities routinely operate in a multi-bunch regime, but applications relying on time-of-flight schemes require single bunch operation. Here we show that pulse picking by resonant excitation in a storage ring creates in addition to the multi-bunch operation a distinct and separable single bunch soft X-ray source. It has variable polarization, a photon flux of up to 10(7)-10(9) ph s(-1)/0.1%BW at purity values of 10(4)-10(2) and a repetition rate of 1.25 MHz. The quasi-resonant excitation of incoherent betatron oscillations of electrons allows horizontal pulse separation at variable (also circular) polarization accessible for both, regular 30 ps pulses and ultrashort pulses of 2-3 ps duration. Combined with a new generation of angularly resolving electron spectrometers this creates unique opportunities for time-resolved photoemission studies as confirmed by time-of-flight spectra. Our pulse picking scheme is particularly suited for surface physics at diffraction-limited light sources promising ultimate spectral resolution.
Y1  - 2014
U6  - https://doi.org/10.1038/ncomms5010
SN  - 2041-1723
VL  - 5
PB  - Nature Publ. Group
CY  - London
ER  - 
TY  - JOUR
A1  - Beim Graben, Peter
T1  - Contextual emergence of intentionality
JF  - Journal of consciousness studies : controversies in science & the humanities ; an international multi-disciplinary journal
N2  - By means of an intriguing physical example, magnetic surface swimmers, that can be described in terms of Dennett's intentional stance, I reconstruct a hierarchy of necessary and sufficient conditions for the applicability of the intentional strategy. It turns out that the different levels of the intentional hierarchy are contextually emergent from their respective subjacent levels by imposing stability constraints upon them. At the lowest level of the hierarchy, phenomenal physical laws emerge for the coarse-grained description of open, nonlinear, and dissipative non-equilibrium systems in critical states. One level higher, dynamic patterns, such as, for example, magnetic surface swimmers, are contextually emergent as they are invariant under certain symmetry operations. Again one level up, these patterns behave apparently rationally by selecting optimal pathways for the dissipation of energy that is delivered by external gradients. This is in accordance with the restated Second Law of thermodynamics as a stability criterion. At the highest level, true believers are intentional systems that are stable under exchanging their observation conditions.
Y1  - 2014
SN  - 1355-8250
VL  - 21
IS  - 5-6
SP  - 75
EP  - 96
PB  - Imprint Academic
CY  - Exeter
ER  - 
TY  - JOUR
A1  - Komarov, Maxim
A1  - Gupta, Shamik
A1  - Pikovskij, Arkadij
T1  - Synchronization transitions in globally coupled rotors in the presence of noise and inertia: Exact results
JF  - epl : a letters journal exploring the frontiers of physics
N2  - We study a generic model of globally coupled rotors that includes the effects of noise, phase shift in the coupling, and distributions of moments of inertia and natural frequencies of oscillation. As particular cases, the setup includes previously studied Sakaguchi-Kuramoto, Hamiltonian and Brownian mean-field, and Tanaka-Lichtenberg-Oishi and Acebron-Bonilla-Spigler models. We derive an exact solution of the self-consistent equations for the order parameter in the stationary state, valid for arbitrary parameters in the dynamics, and demonstrate nontrivial phase transitions to synchrony that include reentrant synchronous regimes. Copyright (C) EPLA, 2014
Y1  - 2014
U6  - https://doi.org/10.1209/0295-5075/106/40003
SN  - 0295-5075
SN  - 1286-4854
VL  - 106
IS  - 4
PB  - EDP Sciences
CY  - Mulhouse
ER  - 
TY  - JOUR
A1  - Miedema, Piter S.
A1  - Wernet, Philippe
A1  - Föhlisch, Alexander
T1  - State-dependent fluorescence yields through the core-valence Coulomb exchange parameter
JF  - Physical review : A, Atomic, molecular, and optical physics
N2  - Total and partial fluorescence yield (PFY) L-edge x-ray absorption spectra differ from the transmission x-ray absorption spectra (XAS) through state-dependent fluorescence yield across the XAS. For 3d(1) to 3d(9) in octahedral symmetry we apply simulations of PFY and XAS and show how the atomic 2p3d Coulomb exchange parameter G(pd) governs the differences in the L-3/(L-2 + L-3) branching ratio between PFY and XAS. G(pd) orders the XAS final states following Hund's rules creating a strong state-dependent fluorescence decay strength variation across the XAS leading to the differences between PFY and XAS.
Y1  - 2014
U6  - https://doi.org/10.1103/PhysRevA.89.052507
SN  - 1050-2947
SN  - 1094-1622
VL  - 89
IS  - 5
PB  - American Physical Society
CY  - College Park
ER  - 
TY  - JOUR
A1  - Di Pietro, Riccardo
A1  - Venkateshvaran, Deepak
A1  - Klug, Andreas
A1  - List-Kratochvil, Emil J. W.
A1  - Facchetti, Antonio
A1  - Sirringhaus, Henning
A1  - Neher, Dieter
T1  - Simultaneous extraction of charge density dependent mobility and variable contact resistance from thin film transistors
JF  - Applied physics letters
N2  - A model for the extraction of the charge density dependent mobility and variable contact resistance in thin film transistors is proposed by performing a full derivation of the current-voltage characteristics both in the linear and saturation regime of operation. The calculated values are validated against the ones obtained from direct experimental methods. This approach allows unambiguous determination of gate voltage dependent contact and channel resistance from the analysis of a single device. It solves the inconsistencies in the commonly accepted mobility extraction methods and provides additional possibilities for the analysis of the injection and transport processes in semiconducting materials. (C) 2014 AIP Publishing LLC.
Y1  - 2014
U6  - https://doi.org/10.1063/1.4876057
SN  - 0003-6951
SN  - 1077-3118
VL  - 104
IS  - 19
PB  - American Institute of Physics
CY  - Melville
ER  - 
TY  - JOUR
A1  - Levnajic, Zoran
A1  - Pikovskij, Arkadij
T1  - Untangling complex dynamical systems via derivative-variable correlations
JF  - Scientific reports
N2  - Inferring the internal interaction patterns of a complex dynamical system is a challenging problem. Traditional methods often rely on examining the correlations among the dynamical units. However, in systems such as transcription networks, one unit's variable is also correlated with the rate of change of another unit's variable. Inspired by this, we introduce the concept of derivative-variable correlation, and use it to design a new method of reconstructing complex systems (networks) from dynamical time series. Using a tunable observable as a parameter, the reconstruction of any system with known interaction functions is formulated via a simple matrix equation. We suggest a procedure aimed at optimizing the reconstruction from the time series of length comparable to the characteristic dynamical time scale. Our method also provides a reliable precision estimate. We illustrate the method's implementation via elementary dynamical models, and demonstrate its robustness to both model error and observation error.
Y1  - 2014
U6  - https://doi.org/10.1038/srep05030
SN  - 2045-2322
VL  - 4
PB  - Nature Publ. Group
CY  - London
ER  - 
TY  - JOUR
A1  - Shin, Jaeoh
A1  - Cherstvy, Andrey G.
A1  - Metzler, Ralf
T1  - Mixing and segregation of ring polymers: spatial confinement and molecular crowding effects
JF  - New journal of physics : the open-access journal for physics
N2  - During the life cycle of bacterial cells the non-mixing of the two ring-shaped daughter genomes is an important prerequisite for the cell division process. Mimicking the environments inside highly crowded biological cells, we study the dynamics and statistical behavior of two flexible ring polymers in the presence of cylindrical confinement and crowding molecules. From extensive computer simulations we determine the degree of ring-ring overlap and the number of inter-monomer contacts for varying volume fractions phi of crowders. We also examine the entropic demixing of polymer rings in the presence of mobile crowders and determine the characteristic times of the internal polymer dynamics. Effects of the ring length on ring-ring overlap are also analyzed. In particular, on systematic variation of the fraction of crowding molecules, a (1 - phi)-scaling is found for the ring-ring overlap length along the cylinder axis, and a non-monotonic dependence of the 3D ring-ring contact number with a maximum at phi approximate to 0.2 is obtained. Our results demonstrate that polymer rings are demixed and separated by particular entropy-favourable partitioning of crowders along the axis of the cylindrical simulation box. These findings help to rationalize the implications of macromolecular crowding for circular DNA molecules in confined spaces inside bacteria as well as in localized cellular compartments inside eukaryotic cells.
KW  - polymers
KW  - confinement
KW  - crowding
Y1  - 2014
U6  - https://doi.org/10.1088/1367-2630/16/5/053047
SN  - 1367-2630
VL  - 16
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  - 
TY  - JOUR
A1  - Toeroek, T.
A1  - Kliem, Bernhard
A1  - Berger, M. A.
A1  - Linton, M. G.
A1  - Demoulin, Pascal
A1  - van Driel-Gesztelyi, L.
T1  - The evolution of writhe in kink-unstable flux ropes and erupting filaments
JF  - Plasma physics and controlled fusion
N2  - The helical kink instability of a twisted magnetic flux tube has been suggested as a trigger mechanism for solar filament eruptions and coronal mass ejections (CMEs). In order to investigate if estimations of the pre-emptive twist can be obtained from observations of writhe in such events, we quantitatively analyze the conversion of twist into writhe in the course of the instability, using numerical simulations. We consider the line tied, cylindrically symmetric Gold-Hoyle flux rope model and measure the writhe using the formulae by Berger and Prior which express the quantity as a single integral in space. We find that the amount of twist converted into writhe does not simply scale with the initial flux rope twist, but depends mainly on the growth rates of the instability eigenmodes of higher longitudinal order than the basic mode. The saturation levels of the writhe, as well as the shapes of the kinked flux ropes, are very similar for considerable ranges of initial flux rope twists, which essentially precludes estimations of pre-eruptive twist from measurements of writhe. However, our simulations suggest an upper twist limit of similar to 6 pi for the majority of filaments prior to their eruption.
KW  - magnetohydrodynamics (MHD)
KW  - Sun: corona
KW  - Sun: filaments
Y1  - 2014
U6  - https://doi.org/10.1088/0741-3335/56/6/064012
SN  - 0741-3335
SN  - 1361-6587
VL  - 56
IS  - 6
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  - 
TY  - JOUR
A1  - Abramowski, Attila
A1  - Aharonian, Felix A.
A1  - Benkhali, Faical  Ait
A1  - Akhperjanian, A. G.
A1  - Angüner, Ekrem Oǧuzhan
A1  - Anton, Gisela
A1  - Balenderan, Shangkari
A1  - Balzer, Arnim
A1  - Barnacka, Anna
A1  - Becherini, Yvonne
A1  - Tjus, J. Becker
A1  - Bernlöhr, K.
A1  - Birsin, E.
A1  - Bissaldi, E.
A1  - Biteau, Jonathan
A1  - Boettcher, Markus
A1  - Boisson, Catherine
A1  - Bolmont, J.
A1  - Bordas, Pol
A1  - Brucker, J.
A1  - Brun, Francois
A1  - Brun, Pierre
A1  - Bulik, Tomasz
A1  - Carrigan, Svenja
A1  - Casanova, Sabrina
A1  - Cerruti, M.
A1  - Chadwick, Paula M.
A1  - Chalme-Calvet, R.
A1  - Chaves, Ryan C. G.
A1  - Cheesebrough, A.
A1  - Chretien, M.
A1  - Colafrancesco, Sergio
A1  - Cologna, Gabriele
A1  - Conrad, Jan
A1  - Couturier, C.
A1  - Cui, Y.
A1  - Dalton, M.
A1  - Daniel, M. K.
A1  - Davids, I. D.
A1  - Degrange, B.
A1  - Deil, C.
A1  - deWilt, P.
A1  - Dickinson, H. J.
A1  - Djannati-Ataï, A.
A1  - Domainko, W.
A1  - Dubus, G.
A1  - Dutson, K.
A1  - Dyks, J.
A1  - Dyrda, M.
A1  - Edwards, T.
A1  - Egberts, Kathrin
A1  - Eger, P.
A1  - Espigat, P.
A1  - Farnier, C.
A1  - Fegan, S.
A1  - Feinstein, F.
A1  - Fernandes, M. V.
A1  - Fernandez, D.
A1  - Fiasson, A.
A1  - Fontaine, G.
A1  - Foerster, A.
A1  - Fuessling, Matthias
A1  - Gajdus, M.
A1  - Gallant, Y. A.
A1  - Garrigoux, T.
A1  - Giavitto, G.
A1  - Giebels, B.
A1  - Glicenstein, J. F.
A1  - Grondin, M. -H.
A1  - Grudzinska, M.
A1  - Haeffner, S.
A1  - Hahn, J.
A1  - Harris, J.
A1  - Heinzelmann, G.
A1  - Henri, G.
A1  - Hermann, G.
A1  - Hervet, O.
A1  - Hillert, A.
A1  - Hinton, James Anthony
A1  - Hofmann, W.
A1  - Hofverberg, P.
A1  - Holler, M.
A1  - Horns, D.
A1  - Jacholkowska, A.
A1  - Jahn, C.
A1  - Jamrozy, M.
A1  - Janiak, M.
A1  - Jankowsky, F.
A1  - Jung, I.
A1  - Kastendieck, M. A.
A1  - Katarzynski, K.
A1  - Katz, U.
A1  - Kaufmann, S.
A1  - Khelifi, B.
A1  - Kieffer, M.
A1  - Klepser, S.
A1  - Klochkov, D.
A1  - Kluzniak, W.
A1  - Kneiske, T.
A1  - Kolitzus, D.
A1  - Komin, Nu
A1  - Kosack, K.
A1  - Krakau, S.
A1  - Krayzel, F.
A1  - Krueger, P. P.
A1  - Laffon, H.
A1  - Lamanna, G.
A1  - Lefaucheur, J.
A1  - Lemiere, A.
A1  - Lemoine-Goumard, M.
A1  - Lenain, J. -P.
A1  - Lennarz, D.
A1  - Lohse, T.
A1  - Lopatin, A.
A1  - Lu, C. -C.
A1  - Marandon, V.
A1  - Marcowith, Alexandre
A1  - Marx, R.
A1  - Maurin, G.
A1  - Maxted, N.
A1  - Mayer, M.
A1  - McComb, T. J. L.
A1  - Mehault, J.
A1  - Meintjes, P. J.
A1  - Menzler, U.
A1  - Meyer, M.
A1  - Moderski, R.
A1  - Mohamed, M.
A1  - Moulin, Emmanuel
A1  - Murach, T.
A1  - Naumann, C. L.
A1  - de Naurois, M.
A1  - Niemiec, J.
A1  - Nolan, S. J.
A1  - Oakes, L.
A1  - Ohm, S.
A1  - Wilhelmi, E. de Ona
A1  - Opitz, B.
A1  - Ostrowski, M.
A1  - Oya, I.
A1  - Panter, M.
A1  - Parsons, R. D.
A1  - Arribas, M. Paz
A1  - Pekeur, N. W.
A1  - Pelletier, G.
A1  - Perez, J.
A1  - Petrucci, P. -O.
A1  - Peyaud, B.
A1  - Pita, S.
A1  - Poon, H.
A1  - Puehlhofer, G.
A1  - Punch, M.
A1  - Quirrenbach, A.
A1  - Raab, S.
A1  - Raue, M.
A1  - Reimer, A.
A1  - Reimer, O.
A1  - Renaud, M.
A1  - de los Reyes, R.
A1  - Rieger, F.
A1  - Rob, L.
A1  - Romoli, C.
A1  - Rosier-Lees, S.
A1  - Rowell, G.
A1  - Rudak, B.
A1  - Rulten, C. B.
A1  - Sahakian, V.
A1  - Sanchez, David M.
A1  - Santangelo, Andrea
A1  - Schlickeiser, R.
A1  - Schuessler, F.
A1  - Schulz, A.
A1  - Schwanke, U.
A1  - Schwarzburg, S.
A1  - Schwemmer, S.
A1  - Sol, H.
A1  - Spengler, G.
A1  - Spies, F.
A1  - Stawarz, L.
A1  - Steenkamp, R.
A1  - Stegmann, Christian
A1  - Stinzing, F.
A1  - Stycz, K.
A1  - Sushch, Iurii
A1  - Szostek, A.
A1  - Tavernet, J. -P.
A1  - Tavernier, T.
A1  - Taylor, A. M.
A1  - Terrier, R.
A1  - Tluczykont, M.
A1  - Trichard, C.
A1  - Valerius, K.
A1  - van Eldik, C.
A1  - van Soelen, B.
A1  - Vasileiadis, G.
A1  - Venter, C.
A1  - Viana, A.
A1  - Vincent, P.
A1  - Voelk, H. J.
A1  - Volpe, F.
A1  - Vorster, M.
A1  - Vuillaume, T.
A1  - Wagner, S. J.
A1  - Wagner, P.
A1  - Ward, M.
A1  - Weidinger, M.
A1  - Weitzel, Q.
A1  - White, R.
A1  - Wierzcholska, A.
A1  - Willmann, P.
A1  - Woernlein, A.
A1  - Wouters, D.
A1  - Zabalza, V.
A1  - Zacharias, M.
A1  - Zajczyk, A.
A1  - Zdziarski, A. A.
A1  - Zech, Alraune
A1  - Zechlin, H. -S.
T1  - TeV gamma-ray observations of the young synchrotron-dominated SNRs G1.9+0.3 and G330.2+1.0 with HESS
JF  - Monthly notices of the Royal Astronomical Society
N2  - The non-thermal nature of the X-ray emission from the shell-type supernova remnants (SNRs) G1.9+0.3 and G330.2+1.0 is an indication of intense particle acceleration in the shock fronts of both objects. This suggests that the SNRs are prime candidates for very-high-energy (VHE; E > 0.1 TeV) gamma-ray observations. G1.9+0.3, recently established as the youngest known SNR in the Galaxy, also offers a unique opportunity to study the earliest stages of SNR evolution in the VHE domain. The purpose of this work is to probe the level of VHE gamma-ray emission from both SNRs and use this to constrain their physical properties. Observations were conducted with the H. E. S. S. (High Energy Stereoscopic System) Cherenkov Telescope Array over a more than six-year period spanning 2004-2010. The obtained data have effective livetimes of 67 h for G1.9+0.3 and 16 h for G330.2+1.0. The data are analysed in the context of the multiwavelength observations currently available and in the framework of both leptonic and hadronic particle acceleration scenarios. No significant gamma-ray signal from G1.9+0.3 or G330.2+1.0 was detected. Upper limits (99 per cent confidence level) to the TeV flux from G1.9+0.3 and G330.2+1.0 for the assumed spectral index Gamma = 2.5 were set at 5.6 x 10(-1)3 cm(-2) s(-1) above 0.26 TeV and 3.2 x 10(-12) cm(-2) s(-1) above 0.38 TeV, respectively. In a one-zone leptonic scenario, these upper limits imply lower limits on the interior magnetic field to B-G1.9 greater than or similar to 12 mu G for G1.9+0.3 and to B-G330 greater than or similar to 8 mu G for G330.2+1.0. In a hadronic scenario, the low ambient densities and the large distances to the SNRs result in very low predicted fluxes, for which the H.E.S.S. upper limits are not constraining.
KW  - radiation mechanisms: non-thermal
KW  - ISM: individual objects: SNR G1.9+0.3
KW  - ISM: individual objects: SNR G330.2+1.0
KW  - ISM: magnetic fields
KW  - ISM: supernova remnants
KW  - gamma-rays: ISM
Y1  - 2014
U6  - https://doi.org/10.1093/mnras/stu459
SN  - 0035-8711
SN  - 1365-2966
VL  - 441
IS  - 1
SP  - 790
EP  - 799
PB  - Oxford Univ. Press
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Fox, Andrew J.
A1  - Wakker, Bart P.
A1  - Barger, Kathleen A.
A1  - Hernandez, Audra K.
A1  - Richter, Philipp
A1  - Lehner, Nicolas
A1  - Bland-Hawthorn, Joss
A1  - Charlton, Jane C.
A1  - Westmeier, Tobias
A1  - Thom, Christopher
A1  - Tumlinson, Jason
A1  - Misawa, Toru
A1  - Howk, J. Christopher
A1  - Haffner, L. Matthew
A1  - Ely, Justin
A1  - Rodriguez-Hidalgo, Paola
A1  - Kumari, Nimisha
T1  - The COS/UVES absorption survey of the magellanic stream. III. Ionization, total mass, and inflow rate onto the milky way
JF  - The astrophysical journal : an international review of spectroscopy and astronomical physics
N2  - Dynamic interactions between the two Magellanic Clouds have flung large quantities of gas into the halo of the Milky Way. The result is a spectacular arrangement of gaseous structures, including the Magellanic Stream, the Magellanic Bridge, and the Leading Arm (collectively referred to as the Magellanic System). In this third paper of a series studying the Magellanic gas in absorption, we analyze the gas ionization level using a sample of 69 Hubble Space Telescope/Cosmic Origins Spectrograph sightlines that pass through or within 30 degrees of the 21 cm emitting regions. We find that 81% (56/69) of the sightlines show UV absorption at Magellanic velocities, indicating that the total cross-section of the Magellanic System is approximate to 11,000 deg(2), or around one-quarter of the entire sky. Using observations of the Si III/Si II ratio together with Cloudy photoionization modeling, we calculate the total gas mass (atomic plus ionized) of the Magellanic System to be approximate to 2.0 x 10(9) M-circle dot (d/55 kpc)(2), with the ionized gas contributing around three times as much mass as the atomic gas. This is larger than the current-day interstellar H I mass of both Magellanic Clouds combined, indicating that they have lost most of their initial gas mass. If the gas in the Magellanic System survives to reach the Galactic disk over its inflow time of similar to 0.5-1.0 Gyr, it will represent an average inflow rate of similar to 3.7-6.7 M-circle dot yr(-1), potentially raising the Galactic star formation rate. However, multiple signs of an evaporative interaction with the hot Galactic corona indicate that the Magellanic gas may not survive its journey to the disk fully intact and will instead add material to (and cool) the corona.
KW  - Galaxy: evolution
KW  - Galaxy: halo
KW  - ISM: abundances
KW  - Magellanic Clouds
KW  - quasars: absorption lines
Y1  - 2014
U6  - https://doi.org/10.1088/0004-637X/787/2/147
SN  - 0004-637X
SN  - 1538-4357
VL  - 787
IS  - 2
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  - 
TY  - JOUR
A1  - Aliu, E.
A1  - Archambault, S.
A1  - Aune, T.
A1  - Behera, B.
A1  - Beilicke, M.
A1  - Benbow, W.
A1  - Berger, K.
A1  - Bird, R.
A1  - Buckley, J. H.
A1  - Bugaev, V.
A1  - Cardenzana, J. V.
A1  - Cerruti, M.
A1  - Chen, Xuhui
A1  - Ciupik, L.
A1  - Collins-Hughes, E.
A1  - Connolly, M. P.
A1  - Cui, W.
A1  - Dumm, J.
A1  - Dwarkadas, Vikram V.
A1  - Errando, M.
A1  - Falcone, A.
A1  - Federici, Simone
A1  - Feng, Q.
A1  - Finley, J. P.
A1  - Fleischhack, H.
A1  - Fortin, P.
A1  - Fortson, L.
A1  - Furniss, A.
A1  - Galante, N.
A1  - Gall, D.
A1  - Gillanders, G. H.
A1  - Griffin, S.
A1  - Griffiths, S. T.
A1  - Grube, J.
A1  - Gyuk, G.
A1  - Hanna, D.
A1  - Holder, J.
A1  - Hughes, G.
A1  - Humensky, T. B.
A1  - Kaaret, P.
A1  - Kertzman, M.
A1  - Khassen, Y.
A1  - Kieda, D.
A1  - Krennrich, F.
A1  - Kumar, S.
A1  - Lang, M. J.
A1  - Madhavan, A. S.
A1  - Maier, G.
A1  - McCann, A. J.
A1  - Meagher, K.
A1  - Millis, J.
A1  - Moriarty, P.
A1  - Mukherjee, R.
A1  - Nieto, D.
A1  - Ong, R. A.
A1  - Otte, A. N.
A1  - Pandel, D.
A1  - Park, N.
A1  - Pohl, Martin
A1  - Popkow, A.
A1  - Prokoph, H.
A1  - Quinn, J.
A1  - Ragan, K.
A1  - Rajotte, J.
A1  - Ratliff, G.
A1  - Reyes, L. C.
A1  - Reynolds, P. T.
A1  - Richards, G. T.
A1  - Roache, E.
A1  - Rousselle, J.
A1  - Sembroski, G. H.
A1  - Shahinyan, K.
A1  - Sheidaei, F.
A1  - Smith, A. W.
A1  - Staszak, D.
A1  - Telezhinsky, Igor O.
A1  - Tsurusaki, K.
A1  - Tucci, J. V.
A1  - Tyler, J.
A1  - Varlotta, A.
A1  - Vassiliev, V. V.
A1  - Vincent, S.
A1  - Wakely, S. P.
A1  - Ward, J. E.
A1  - Weinstein, A.
A1  - Welsing, R.
A1  - Wilhelm, Alina
T1  - Investigating the TeV morpholoy of MGRO J1908+06 with veritas
JF  - The astrophysical journal : an international review of spectroscopy and astronomical physics
N2  - We report on deep observations of the extended TeV gamma-ray source MGRO J1908+06 made with the VERITAS very high energy gamma-ray observatory. Previously, the TeV emission has been attributed to the pulsar wind nebula (PWN) of the Fermi-LAT pulsar PSR J1907+0602. We detect MGRO J1908+06 at a significance level of 14 standard deviations (14 sigma) and measure a photon index of 2.20 +/- 0.10(stat) +/- 0.20(sys). The TeV emission is extended, covering the region near PSR J1907+0602 and also extending toward SNR G40.5-0.5. When fitted with a two-dimensional Gaussian, the intrinsic extension has a standard deviation of sigma(src) = 0 degrees.44 +/- 0 degrees.02. In contrast to other TeV PWNe of similar age in which the TeV spectrum softens with distance from the pulsar, the TeV spectrum measured near the pulsar location is consistent with that measured at a position near the rim of G40.5-0.5, 0 degrees.33 away.
KW  - gamma rays: general
KW  - gamma-ray burst: individual (MGRO J1908+06, VER J1907+062)
KW  - pulsars: individual (PSR J1907+0602)
KW  - ISM: supernova remnants
Y1  - 2014
U6  - https://doi.org/10.1088/0004-637X/787/2/166
SN  - 0004-637X
SN  - 1538-4357
VL  - 787
IS  - 2
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  - 
TY  - JOUR
A1  - Zaritsky, Dennis
A1  - Courtois, Helene
A1  - Munoz-Mateos, Juan-Carlos
A1  - Sorce, Jenny
A1  - Erroz-Ferrer, S.
A1  - Comeron, S.
A1  - Gadotti, D. A.
A1  - Gil De Paz, A.
A1  - Hinz, J. L.
A1  - Laurikainen, E.
A1  - Kim, T.
A1  - Laine, J.
A1  - Menendez-Delmestre, K.
A1  - Mizusawa, T.
A1  - Regan, M. W.
A1  - Salo, H.
A1  - Seibert, M.
A1  - Sheth, K.
A1  - Athanassoula, E.
A1  - Bosma, A.
A1  - Cisternas, M.
A1  - Ho, Luis C.
A1  - Holwerda, B.
T1  - The baryonic Tully-Fisher relationship for S(4)G galaxies and the  "condensed" baryon fraction of galaxies
JF  - The astronomical journal
N2  - We combine data from the Spitzer Survey for Stellar Structure in Galaxies, a recently calibrated empirical stellar mass estimator from Eskew et al., and an extensive database of Hi spectral line profiles to examine the baryonic Tully-Fisher (BTF) relation. We find (1) that the BTF has lower scatter than the classic Tully-Fisher (TF) relation and is better described as a linear relationship, confirming similar previous results, (2) that the inclusion of a radial scale in the BTF decreases the scatter but only modestly, as seen previously for the TF relation, and (3) that the slope of the BTF, which we find to be 3.5 +/- 0.2 (Delta log M-baryon/Delta log v(c)), implies that on average a nearly constant fraction (similar to 0.4) of all baryons expected to be in a halo are "condensed" onto the central region of rotationally supported galaxies. The condensed baryon fraction, M-baryon/M-total, is, to our measurement precision, nearly independent of galaxy circular velocity (our sample spans circular velocities, vc, between 60 and 250 km s(-1), but is extended to v(c) similar to 10 km s(-1) using data from the literature). The observed galaxy-to-galaxy scatter in this fraction is generally <= a factor of 2 despite fairly liberal selection criteria. These results imply that cooling and heating processes, such as cold versus hot accretion, mass loss due to stellar winds, and active galactic nucleus driven feedback, to the degree that they affect the global galactic properties involved in the BTF, are independent of halo mass for galaxies with 10 < v(c) < 250 km s(-1) and typically introduce no more than a factor of two range in the resulting M-baryon/M-total. Recent simulations by Aumer et al. of a small sample of disk galaxies are in excellent agreement with our data, suggesting that current simulations are capable of reproducing the global properties of individual disk galaxies. More detailed comparison to models using the BTF holds great promise, but awaits improved determinations of the stellar masses.
KW  - galaxies: evolution
KW  - galaxies: formation
KW  - galaxies: fundamental parameters
KW  - galaxies: stellar content
KW  - galaxies: structure
Y1  - 2014
U6  - https://doi.org/10.1088/0004-6256/147/6/134
SN  - 0004-6256
SN  - 1538-3881
VL  - 147
IS  - 6
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  - 
TY  - JOUR
A1  - Mengel, Matthias
A1  - Levermann, Anders
T1  - Ice plug prevents irreversible discharge from East Antarctica
JF  - Nature climate change
N2  - Changes in ice discharge from Antarctica constitute the largest uncertainty in future sea-level projections, mainly because of the unknown response of its marine basins(1). Most of West Antarctica's marine ice sheet lies on an inland-sloping bed(2) and is thereby prone to a marine ice sheet instability(3-5). A similar topographic configuration is found in large parts of East Antarctica, which holds marine ice equivalent to 19 m of global sea-level rise(6), that is, more than five times that of West Antarctica. Within East Antarctica, the Wilkes Basin holds the largest volume of marine ice that is fully connected by subglacial troughs. This ice body was significantly reduced during the Pliocene epoch(7). Strong melting underneath adjacent ice shelves with similar bathymetry(8) indicates the ice sheet's sensitivity to climatic perturbations. The stability of the Wilkes marine ice sheet has not been the subject of any comprehensive assessment of future sea level. Using recently improved topographic data(6) in combination with ice-dynamic simulations, we show here that the removal of a specific coastal ice volume equivalent to less than 80 mm of global sea-level rise at the margin of the Wilkes Basin destabilizes the regional ice flow and leads to a self-sustained discharge of the entire basin and a global sea-level rise of 3-4 m. Our results are robust with respect to variation in ice parameters, forcing details and model resolution as well as increased surface mass balance, indicating that East Antarctica may become a large contributor to future sea-level rise on timescales beyond a century.
Y1  - 2014
U6  - https://doi.org/10.1038/NCLIMATE2226
SN  - 1758-678X
SN  - 1758-6798
VL  - 4
IS  - 6
SP  - 451
EP  - 455
PB  - Nature Publ. Group
CY  - London
ER  - 
TY  - JOUR
A1  - Vlasov, Vladimir
A1  - Macau, Elbert E. N.
A1  - Pikovskij, Arkadij
T1  - Synchronization of oscillators in a Kuramoto-type model with generic coupling
JF  - Chaos : an interdisciplinary journal of nonlinear science
N2  - We study synchronization properties of coupled oscillators on networks that allow description in terms of global mean field coupling. These models generalize the standard Kuramoto-Sakaguchi model, allowing for different contributions of oscillators to the mean field and to different forces from the mean field on oscillators. We present the explicit solutions of self-consistency equations for the amplitude and frequency of the mean field in a parametric form, valid for noise-free and noise-driven oscillators. As an example, we consider spatially spreaded oscillators for which the coupling properties are determined by finite velocity of signal propagation. (C) 2014 AIP Publishing LLC.
Y1  - 2014
U6  - https://doi.org/10.1063/1.4880835
SN  - 1054-1500
SN  - 1089-7682
VL  - 24
IS  - 2
PB  - American Institute of Physics
CY  - Melville
ER  - 
TY  - JOUR
A1  - Mulansky, Mario
T1  - Scaling of chaos in strongly nonlinear lattices
JF  - Chaos : an interdisciplinary journal of nonlinear science
N2  - Although it is now understood that chaos in complex classical systems is the foundation of thermodynamic behavior, the detailed relations between the microscopic properties of the chaotic dynamics and the macroscopic thermodynamic observations still remain mostly in the dark. In this work, we numerically analyze the probability of chaos in strongly nonlinear Hamiltonian systems and find different scaling properties depending on the nonlinear structure of the model. We argue that these different scaling laws of chaos have definite consequences for the macroscopic diffusive behavior, as chaos is the microscopic mechanism of diffusion. This is compared with previous results on chaotic diffusion [M. Mulansky and A. Pikovsky, New J. Phys. 15, 053015 (2013)], and a relation between microscopic chaos and macroscopic diffusion is established. (C) 2014 AIP Publishing LLC.
Y1  - 2014
U6  - https://doi.org/10.1063/1.4868259
SN  - 1054-1500
SN  - 1089-7682
VL  - 24
IS  - 2
PB  - American Institute of Physics
CY  - Melville
ER  - 
TY  - JOUR
A1  - Reindl, Nicole
A1  - Rauch, Thomas
A1  - Werner, Klaus
A1  - Kruk, J. W.
A1  - Todt, Helge Tobias
T1  - On helium-dominated stellar evolution: the mysterious role of the O(He)-type stars
JF  - Astronomy and astrophysics : an international weekly journal
N2  - Context. About a quarter of all post-asymptotic giant branch (AGB) stars are hydrogen-deficient. Stellar evolutionary models explain the carbon-dominated H-deficient stars by a (very) late thermal pulse scenario where the hydrogen-rich envelope is mixed with the helium-rich intershell layer. Depending on the particular time at which the final flash occurs, the entire hydrogen envelope may be burned. In contrast, helium-dominated post-AGB stars and their evolution are not yet understood.
 Aims. A small group of very hot, helium-dominated stars is formed by O(He)-type stars. A precise analysis of their photospheric abundances will establish constraints to their evolution.
 Methods. We performed a detailed spectral analysis of ultraviolet and optical spectra of four O(He) stars by means of state-of-the-art non-LTE model-atmosphere techniques.
 Results. We determined effective temperatures, surface gravities, and the abundances of H, He, C, N, O, F, Ne, Si, P, S, Ar, and Fe. By deriving upper limits for the mass-loss rates of the O(He) stars, we found that they do not exhibit enhanced mass-loss. The comparison with evolutionary models shows that the status of the O(He) stars remains uncertain. Their abundances match predictions of a double helium white dwarf (WD) merger scenario, suggesting that they might be the progeny of the compact and of the luminous helium-rich sdO-type stars. The existence of planetary nebulae that do not show helium enrichment around every other O(He) star precludes a merger origin for these stars. These stars must have formed in a different way, for instance via enhanced mass-loss during their post-AGB evolution or a merger within a common-envelope (CE) of a CO-WD and a red giant or AGB star.
 Conclusions. A helium-dominated stellar evolutionary sequence exists that may be fed by different types of mergers or CE scenarios. It appears likely that all these pass through the O(He) phase just before they become WDs.
KW  - stars: AGB and post-AGB
KW  - stars: evolution
KW  - stars: fundamental parameters
KW  - stars: abundances
Y1  - 2014
U6  - https://doi.org/10.1051/0004-6361/201423498
SN  - 0004-6361
SN  - 1432-0746
VL  - 566
PB  - EDP Sciences
CY  - Les Ulis
ER  - 
TY  - JOUR
A1  - Oskinova, Lidia M.
A1  - Naze, Yael
A1  - Todt, Helge Tobias
A1  - Huenemoerder, David P.
A1  - Ignace, Richard
A1  - Hubrig, Swetlana
A1  - Hamann, Wolf-Rainer
T1  - Discovery of X-ray pulsations from a massive star
JF  - Nature Communications
N2  - X-ray emission from stars much more massive than the Sun was discovered only 35 years ago. Such stars drive fast stellar winds where shocks can develop, and it is commonly assumed that the X-rays emerge from the shock-heated plasma. Many massive stars additionally pulsate. However, hitherto it was neither theoretically predicted nor observed that these pulsations would affect their X-ray emission. All X-ray pulsars known so far are associated with degenerate objects, either neutron stars or white dwarfs. Here we report the discovery of pulsating X-rays from a non-degenerate object, the massive B-type star xi(1) CMa. This star is a variable of beta Cep-type and has a strong magnetic field. Our observations with the X-ray Multi-Mirror (XMM-Newton) telescope reveal X-ray pulsations with the same period as the fundamental stellar oscillations. This discovery challenges our understanding of stellar winds from massive stars, their X-ray emission and their magnetism.
Y1  - 2014
U6  - https://doi.org/10.1038/ncomms5024
SN  - 2041-1723
VL  - 5
PB  - Nature Publ. Group
CY  - London
ER  - 
TY  - JOUR
A1  - Maistrenko, Yuri
A1  - Penkovsky, Bogdan
A1  - Rosenblum, Michael
T1  - Solitary state at the edge of synchrony in ensembles with attractive and repulsive interactions
JF  - Physical review : E, Statistical, nonlinear and soft matter physics
N2  - We discuss the desynchronization transition in networks of globally coupled identical oscillators with attractive and repulsive interactions. We show that, if attractive and repulsive groups act in antiphase or close to that, a solitary state emerges with a single repulsive oscillator split up from the others fully synchronized. With further increase of the repulsing strength, the synchronized cluster becomes fuzzy and the dynamics is given by a variety of stationary states with zero common forcing. Intriguingly, solitary states represent the natural link between coherence and incoherence. The phenomenon is described analytically for phase oscillators with sine coupling and demonstrated numerically for more general amplitude models.
Y1  - 2014
U6  - https://doi.org/10.1103/PhysRevE.89.060901
SN  - 1539-3755
SN  - 1550-2376
VL  - 89
IS  - 6
PB  - American Physical Society
CY  - College Park
ER  -