@article{AbdallaAdamAharonianetal.2020,
  author    = {Abdalla, H. and Adam, R. and Aharonian, Felix A. and Benkhali, F. Ait and Ang{\"u}ner, Ekrem Oǧuzhan and Arcaro, C. and Armand, C. and Armstrong, T. and Ashkar, H. and Backes, M. and Baghmanyan, V. and Martins, V. Barbosa and Barnacka, A. and Barnard, M. and Becherini, Y. and Berge, D. and Bernlohr, K. and Bi, B. and Bottcher, M. and Boisson, C. and Bolmont, J. and de Lavergne, M. de Bony and Bordas, Pol and Breuhaus, M. and Brun, F. and Brun, P. and Bryan, M. and Buchele, M. and Bulik, T. and Bylund, T. and Caroff, S. and Carosi, A. and Casanova, Sabrina and Chand, T. and Chandra, S. and Chen, A. and Cotter, G. and Curylo, M. and Mbarubucyeye, J. Damascene and Davids, I. D. and Davies, J. and Deil, C. and Devin, J. and deWilt, P. and Dirson, L. and Djannati-Atai, A. and Dmytriiev, A. and Donath, A. and Doroshenko, V. and Duffy, C. and Dyks, J. and Egberts, Kathrin and Eichhorn, F. and Einecke, S. and Emery, G. and Ernenwein, J. -P. and Feijen, K. and Fegan, S. and Fiasson, A. and de Clairfontaine, G. Fichet and Fontaine, G. and Funk, S. and Fussling, Matthias and Gabici, S. and Gallant, Y. A. and Giavitto, G. and Giunti, L. and Glawion, D. and Glicenstein, J. F. and Gottschall, D. and Grondin, M. -H. and Hahn, J. and Haupt, M. and Hermann, G. and Hinton, J. A. and Hofmann, W. and Hoischen, Clemens and Holch, T. L. and Holler, M. and Horbe, M. and Horns, D. and Huber, D. and Jamrozy, M. and Jankowsky, D. and Jankowsky, F. and Jardin-Blicq, A. and Joshi, V. and Jung-Richardt, I. and Kasai, E. and Kastendieck, M. A. and Katarzynski, K. and Katz, U. and Khangulyan, D. and Khelifi, B. and Klepser, S. and Kluzniak, W. and Komin, Nu. and Konno, R. and Kosack, K. and Kostunin, D. and Kreter, M. and Lamanna, G. and Lemiere, A. and Lemoine-Goumard, M. and Lenain, J. -P. and Levy, C. and Lohse, T. and Lypova, I. and Mackey, J. and Majumdar, J. and Malyshev, D. and Malyshev, D. and Marandon, V. and Marchegiani, P. and Marcowith, Alexandre and Mares, A. and Marti-Devesa, G. and Marx, R. and Maurin, G. and Meintjes, P. J. and Meyer, M. and Mitchell, A. and Moderski, R. and Mohamed, M. and Mohrmann, L. and Montanari, A. and Moore, C. and Morris, P. and Moulin, Emmanuel and Muller, J. and Murach, T. and Nakashima, K. and Nayerhoda, A. and de Naurois, M. and Ndiyavala, H. and Niederwanger, F. and Niemiec, J. and Oakes, L. and O'Brien, Patrick and Odaka, H. and Ohm, S. and Olivera-Nieto, L. and Wilhelmi, E. de Ona and Ostrowski, M. and Oya, I. and Panter, M. and Panny, S. and Parsons, R. D. and Peron, G. and Peyaud, B. and Piel, Q. and Pita, S. and Poireau, V. and Noel, A. Priyana and Prokhorov, D. A. and Prokoph, H. and Puhlhofer, G. and Punch, M. and Quirrenbach, A. and Raab, S. and Rauth, R. and Reichherzer, P. and Reimer, A. and Reimer, O. and Remy, Q. and Renaud, M. and Rieger, F. and Rinchiuso, L. and Romoli, C. and Rowell, G. and Rudak, B. and Ruiz-Velasco, E. and Sahakian, V. and Sailer, S. and Sanchez, D. A. and Santangelo, A. and Sasaki, M. and Scalici, M. and Schussler, F. and Schutte, H. M. and Schwanke, U. and Schwemmer, S. and Seglar-Arroyo, M. and Senniappan, M. and Seyffert, A. S. and Shafi, N. and Shiningayamwe, K. and Simoni, R. and Sinha, A. and Sol, H. and Specovius, A. and Spencer, S. and Spir-Jacob, M. and Stawarz, L. and Sun, L. and Steenkamp, R. and Stegmann, C. and Steinmassl, S. and Steppa, C. and Takahashi, T. and Tavernier, T. and Taylor, A. M. and Terrier, R. and Tiziani, D. and Tluczykont, M. and Tomankova, L. and Trichard, C. and Tsirou, M. and Tuffs, R. and Uchiyama, Y. and van der Walt, D. J. and van Eldik, C. and van Rensburg, C. and van Soelen, B. and Vasileiadis, G. and Veh, J. and Venter, C. and Vincent, P. and Vink, J. and Volk, H. J. and Vuillaume, T. and Wadiasingh, Z. and Wagner, S. J. and Watson, J. and Werner, F. and White, R. and Wierzcholska, A. and Wong, Yu Wun and Yusafzai, A. and Zacharias, M. and Zanin, R. and Zargaryan, D. and Zdziarski, A. A. and Zech, Alraune and Zhu, S. J. and Ziegler, A. and Zorn, J. and Zouari, S. and Zywucka, N.},
  title     = {An extreme particle accelerator in the Galactic plane},
  series = {Astronomy and astrophysics : an international weekly journal},
  volume    = {644},
  journal   = {Astronomy and astrophysics : an international weekly journal},
  publisher = {EDP Sciences},
  address   = {Les Ulis},
  organization    = {HESS Collaboration},
  issn      = {0004-6361},
  doi       = {10.1051/0004-6361/202038851},
  pages     = {8},
  year      = {2020},
  abstract  = {The unidentified very-high-energy (VHE; E > 0.1 TeV) gamma -ray source, HESS J1826-130, was discovered with the High Energy Stereoscopic System (HESS) in the Galactic plane. The analysis of 215 h of HESS data has revealed a steady gamma -ray flux from HESS J1826-130, which appears extended with a half-width of 0.21 degrees +/- 0.02 <br /> (stat)degrees <br /> stat degrees +/- 0.05 <br /> (sys)degrees sys degrees . The source spectrum is best fit with either a power-law function with a spectral index Gamma = 1.78 +/- 0.10(stat) +/- 0.20(sys) and an exponential cut-off at 15.2 <br /> (+5.5)(-3.2) -3.2+5.5 TeV, or a broken power-law with Gamma (1) = 1.96 +/- 0.06(stat) +/- 0.20(sys), Gamma (2) = 3.59 +/- 0.69(stat) +/- 0.20(sys) for energies below and above E-br = 11.2 +/- 2.7 TeV, respectively. The VHE flux from HESS J1826-130 is contaminated by the extended emission of the bright, nearby pulsar wind nebula, HESS J1825-137, particularly at the low end of the energy spectrum. Leptonic scenarios for the origin of HESS J1826-130 VHE emission related to PSR J1826-1256 are confronted by our spectral and morphological analysis. In a hadronic framework, taking into account the properties of dense gas regions surrounding HESS J1826-130, the source spectrum would imply an astrophysical object capable of accelerating the parent particle population up to greater than or similar to 200 TeV. Our results are also discussed in a multiwavelength context, accounting for both the presence of nearby supernova remnants, molecular clouds, and counterparts detected in radio, X-rays, and TeV energies.},
  language  = {en}
}
@article{AbdallaAdamAharonianetal.2020,
  author    = {Abdalla, Hassan E. and Adam, Remi and Aharonian, Felix A. and Benkhali, Faical Ait and Ang{\"u}ner, Ekrem Oǧuzhan and Arakawa, Masanori and Arcaro, C and Armand, Catherine and Armstrong, T. and Egberts, Kathrin},
  title     = {Very high energy γ-ray emission from two blazars of unknown redshift and upper limits on their distance},
  series = {Monthly Notices of the Royal Astronomical Society},
  volume    = {494},
  journal   = {Monthly Notices of the Royal Astronomical Society},
  number    = {4},
  publisher = {Wiley-Blackwell},
  address   = {Oxford},
  pages     = {13},
  year      = {2020},
  abstract  = {We report on the detection of very high energy (VHE; E > 100 GeV) gamma-ray emission from the BL Lac objects KUV 00311-1938 and PKS 1440-389 with the High Energy Stereoscopic System (H.E.S.S.). H.E.S.S. observations were accompanied or preceded by multiwavelength observations with Fermi/LAT, XRT and UVOT onboard the Swift satellite, and ATOM. Based on an extrapolation of the Fermi/LAT spectrum towards the VHE gamma-ray regime, we deduce a 95 per cent confidence level upper limit on the unknown redshift of KUV 00311-1938 of z < 0.98 and of PKS 1440-389 of z < 0.53. When combined with previous spectroscopy results, the redshift of KUV 00311-1938 is constrained to 0.51 <= z < 0.98 and of PKS 1440-389 to 0.14 (sic) z < 0.53.},
  language  = {en}
}
@misc{AbdallaAdamAharonianetal.2020,
  author    = {Abdalla, Hassan E. and Adam, Remi and Aharonian, Felix A. and Benkhali, Faical Ait and Ang{\"u}ner, Ekrem Oǧuzhan and Arakawa, Masanori and Arcaro, C and Armand, Catherine and Armstrong, T. and Egberts, Kathrin},
  title     = {Very high energy γ-ray emission from two blazars of unknown redshift and upper limits on their distance},
  series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  number    = {4},
  issn      = {1866-8372},
  doi       = {10.25932/publishup-52600},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-526000},
  pages     = {15},
  year      = {2020},
  abstract  = {We report on the detection of very high energy (VHE; E > 100 GeV) gamma-ray emission from the BL Lac objects KUV 00311-1938 and PKS 1440-389 with the High Energy Stereoscopic System (H.E.S.S.). H.E.S.S. observations were accompanied or preceded by multiwavelength observations with Fermi/LAT, XRT and UVOT onboard the Swift satellite, and ATOM. Based on an extrapolation of the Fermi/LAT spectrum towards the VHE gamma-ray regime, we deduce a 95 per cent confidence level upper limit on the unknown redshift of KUV 00311-1938 of z < 0.98 and of PKS 1440-389 of z < 0.53. When combined with previous spectroscopy results, the redshift of KUV 00311-1938 is constrained to 0.51 <= z < 0.98 and of PKS 1440-389 to 0.14 (sic) z < 0.53.},
  language  = {en}
}
@article{AlbrechtWinkelmannLevermann2020,
  author    = {Albrecht, Torsten and Winkelmann, Ricarda and Levermann, Anders},
  title     = {Glacial-cycle simulations of the Antarctic Ice Sheet with the Parallel Ice Sheet Model (PISM)},
  series = {The Cryosphere : TC ; an interactive open access journal of the European Geosciences Union},
  volume    = {14},
  journal   = {The Cryosphere : TC ; an interactive open access journal of the European Geosciences Union},
  number    = {2},
  publisher = {Copernicus Publ.},
  address   = {G{\"o}ttingen},
  issn      = {1994-0416},
  doi       = {10.5194/tc-14-633-2020},
  pages     = {633 -- 656},
  year      = {2020},
  abstract  = {The Parallel Ice Sheet Model (PISM) is applied to the Antarctic Ice Sheet over the last two glacial cycles (approximate to 210 000 years) with a resolution of 16 km. An ensemble of 256 model runs is analyzed in which four relevant model parameters have been systematically varied using full-factorial parameter sampling. Parameters and plausible parameter ranges have been identified in a companion paper (Albrecht et al., 2020) and are associated with ice dynamics, climatic forcing, basal sliding and bed deformation and represent distinct classes of model uncertainties. The model is scored against both modern and geologic data, including reconstructed grounding-line locations, elevation-age data, ice thickness, surface velocities and uplift rates. An aggregated score is computed for each ensemble member that measures the overall model-data misfit, including measurement uncertainty in terms of a Gaussian error model (Briggs and Tarasov, 2013). The statistical method used to analyze the ensemble simulation results follows closely the simple averaging method described in Pollard et al. (2016). This analysis reveals clusters of best-fit parameter combinations, and hence a likely range of relevant model and boundary parameters, rather than individual best-fit parameters. The ensemble of reconstructed histories of Antarctic Ice Sheet volumes provides a score-weighted likely range of sea-level contributions since the Last Glacial Maximum (LGM) of 9.4 +/- 4.1m (or 6.5 +/- 2.0 x 10(6) km(3)), which is at the upper range of most previous studies. The last deglaciation occurs in all ensemble simulations after around 12 000 years before present and hence after the meltwater pulse 1A (MWP1a). Our ensemble analysis also provides an estimate of parametric uncertainty bounds for the present-day state that can be used for PISM projections of future sea-level contributions from the Antarctic Ice Sheet.},
  language  = {en}
}
@article{AldiyarovSokolovAkylbayevaetal.2020,
  author    = {Aldiyarov, Abdurakhman and Sokolov, Dmitriy and Akylbayeva, Aigerim and Nurmukan, Assel and Tokmoldin, Nurlan},
  title     = {On thermal stability of cryovacuum deposited CH4+H2O films},
  series = {Low temperature physics},
  volume    = {46},
  journal   = {Low temperature physics},
  number    = {11},
  publisher = {American Institute of Physics},
  address   = {Melville},
  issn      = {1063-777X},
  doi       = {10.1063/10.0002156},
  pages     = {1121 -- 1124},
  year      = {2020},
  abstract  = {Whereas stable homogenous states of aqueous hydrocarbon solutions are typically observed at high temperatures and pressures far beyond the critical values corresponding to individual components, the stability of such system may be preserved upon transition into the region of metastable states at low temperatures and low pressures. This work is dedicated to the study of the thermal stability of a water-methane mixture formed by cryogenic vapor phase deposition. The obtained thin films were studied using vibrational spectroscopy in the temperature range of 16-180 K. During thermal annealing of the samples, characteristic vibrational C-H modes of methane were monitored alongside the chamber pressure to register both structural changes and desorption of the film material. The obtained results reveal that upon the co-deposition of methane and water, methane molecules appear both in non-bound and trapped states. The observed broadening of the characteristic C-H stretching mode at 3010 cm(-1) upon an increase in temperature of the sample from 16 to 90 K, followed by narrowing of the peak as the temperature is reduced back to 16 K, indicates localization of methane molecules within the water matrix at lower temperatures.},
  language  = {en}
}
@article{AlexoudiMallonnKelesetal.2020,
  author    = {Alexoudi, Xanthippi and Mallonn, Matthias and Keles, Engin and Poppenh{\"a}ger, Katja and von Essen, Carolina and Strassmeier, Klaus},
  title     = {Role of the impact parameter in exoplanet transmission spectroscopy},
  series = {Astronomy and astrophysics : an international weekly journal},
  volume    = {640},
  journal   = {Astronomy and astrophysics : an international weekly journal},
  publisher = {EDP Sciences},
  address   = {Les Ulis},
  issn      = {0004-6361},
  doi       = {10.1051/0004-6361/202038080},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-605378},
  pages     = {9},
  year      = {2020},
  abstract  = {Context Transmission spectroscopy is a promising tool for the atmospheric characterization of transiting exoplanets. Because the planetary signal is faint, discrepancies have been reported regarding individual targets. Aims We investigate the dependence of the estimated transmission spectrum on deviations of the orbital parameters of the star-planet system that are due to the limb-darkening effects of the host star. We describe how the uncertainty on the orbital parameters translates into an uncertainty on the planetary spectral slope. Methods We created synthetic transit light curves in seven different wavelength bands, from the near-ultraviolet to the near-infrared, and fit them with transit models parameterized by fixed deviating values of the impact parameter b. First, we performed a qualitative study to illustrate the effect by presenting the changes in the transmission spectrum slope with different deviations of b. Then, we quantified these variations by creating an error envelope (for centrally transiting, off-center, and grazing systems) based on a derived typical uncertainty on b from the literature. Finally, we compared the variations in the transmission spectra for different spectral types of host stars. Results Our simulations show a wavelength-dependent offset that is more pronounced at the blue wavelengths where the limb-darkening effect is stronger. This offset introduces a slope in the planetary transmission spectrum that becomes steeper with increasing b values. Variations of b by positive or negative values within its uncertainty interval introduce positive or negative slopes, thus the formation of an error envelope. The amplitude from blue optical to near-infrared wavelength for a typical uncertainty on b corresponds to one atmospheric pressure scale height and more. This impact parameter degeneracy is confirmed for different host types; K stars present prominently steeper slopes, while M stars indicate features at the blue wavelengths. Conclusions We demonstrate that transmission spectra can be hard to interpret, basically because of the limitations in defining a precise impact parameter value for a transiting exoplanet. This consequently limits a characterization of its atmosphere.},
  language  = {en}
}
@misc{AlirezaeizanjaniGrossmannPfeiferetal.2020,
  author    = {Alirezaeizanjani, Zahra and Großmann, Robert and Pfeifer, Veronika and Hintsche, Marius and Beta, Carsten},
  title     = {Chemotaxis strategies of bacteria with multiple run modes},
  series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  journal   = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  number    = {22},
  issn      = {1866-8372},
  doi       = {10.25932/publishup-51909},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-519098},
  pages     = {10},
  year      = {2020},
  abstract  = {Bacterial chemotaxis-a fundamental example of directional navigation in the living world-is key to many biological processes, including the spreading of bacterial infections. Many bacterial species were recently reported to exhibit several distinct swimming modes-the flagella may, for example, push the cell body or wrap around it. How do the different run modes shape the chemotaxis strategy of a multimode swimmer? Here, we investigate chemotactic motion of the soil bacterium Pseudomonas putida as a model organism. By simultaneously tracking the position of the cell body and the configuration of its flagella, we demonstrate that individual run modes show different chemotactic responses in nutrition gradients and, thus, constitute distinct behavioral states. On the basis of an active particle model, we demonstrate that switching between multiple run states that differ in their speed and responsiveness provides the basis for robust and efficient chemotaxis in complex natural habitats.},
  language  = {en}
}
@article{AlirezaeizanjaniGrossmannPfeiferetal.2020,
  author    = {Alirezaeizanjani, Zahra and Großmann, Robert and Pfeifer, Veronika and Hintsche, Marius and Beta, Carsten},
  title     = {Chemotaxis strategies of bacteria with multiple run modes},
  series = {Science advances},
  volume    = {6},
  journal   = {Science advances},
  number    = {22},
  publisher = {American Association for the Advancement of Science},
  address   = {Washington},
  issn      = {2375-2548},
  doi       = {10.1126/sciadv.aaz6153},
  pages     = {8},
  year      = {2020},
  abstract  = {Bacterial chemotaxis-a fundamental example of directional navigation in the living world-is key to many biological processes, including the spreading of bacterial infections. Many bacterial species were recently reported to exhibit several distinct swimming modes-the flagella may, for example, push the cell body or wrap around it. How do the different run modes shape the chemotaxis strategy of a multimode swimmer? Here, we investigate chemotactic motion of the soil bacterium Pseudomonas putida as a model organism. By simultaneously tracking the position of the cell body and the configuration of its flagella, we demonstrate that individual run modes show different chemotactic responses in nutrition gradients and, thus, constitute distinct behavioral states. On the basis of an active particle model, we demonstrate that switching between multiple run states that differ in their speed and responsiveness provides the basis for robust and efficient chemotaxis in complex natural habitats.},
  language  = {en}
}
@phdthesis{Arentsen2020,
  author    = {Arentsen, Anke},
  title     = {Galactic archaeology with the oldest stars in the Milky Way},
  doi       = {10.25932/publishup-47602},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-476022},
  school      = {Universit{\"a}t Potsdam},
  year      = {2020},
  abstract  = {In einer dunklen Nacht kann man tausende Sterne sehen. All diese Sterne befinden sich innerhalb der Milchstraße, unsere Heimatgalaxie. Nicht alle Sterne sind gleich, sie k{\"o}nnen zum Beispiel unterschiedliche Gr{\"o}ßen, Massen, Temperaturen und Alter haben. Die schwereren Sterne leben (aus astronomischer Sicht) nicht lange, nur wenige Millionen Jahren, aber Sterne kleiner als die Sonne k{\"o}nnen mehr als zehn Milliarden Jahren alt werden. Kleine Sterne die ganz am Anfang des Universums entstanden sind leuchten immer noch. Diese uralten Sterne sind sehr hilfreich um mehr {\"u}ber das fr{\"u}he Universum, die erste Sterne und die Geschichte der Milchstraße zu erfahren. Aber wie erkennt man uralte Sterne? Anhand ihrer chemischen Fingerabdr{\"u}cke! Am Anfang des Universums gab es nur zwei chemische Elemente: Wasserstoff und Helium (und ein klein bisschen Lithium). Alle schwereren Elementen wie zum Beispiel Kohlenstoff, Kalzium und Eisen sind erst sp{\"a}ter innerhalb von Sternen und in Sternexplosionen entstanden. Je mehr Sternen geboren werden, sich entwickeln und explodieren, desto mehr chemische Elemente gibt es im Universum. Sterne die sp{\"a}ter entstehen werden mit einer gr{\"o}ßeren Menge an schweren Elementen, beziehungsweise einer gr{\"o}ßeren Metallizit{\"a}t, geboren. Im Bereich der Astronomie der sich „Galaktische Arch{\"a}ologie" nennt benutzt man Sterne mit unterschiedlichen Metallizit{\"a}ten um die Geschichte der Milchstraße zu erforschen. In dieser Doktorarbeit liegt der Fokus auf den metallarmen Sterne, da man erwartet dass diese Sterne am {\"a}ltesten sind und uns deswegen viel {\"u}ber die fr{\"u}he Geschichte erz{\"a}hlen k{\"o}nnen. Bis heute haben wir noch keinen metallfreien Stern entdeckt, aber die metall{\"a}rmsten Sterne geben uns wichtige Einblicke in das Leben und Sterben der ersten Sterne. Viele von diesen {\"a}ltesten, metall{\"a}rmsten Sternen haben unerwartet viel Kohlenstoff im Vergleich zu zum Beispiel Eisen. Diese kohlenstoffreichen, metallarmen Sterne (CEMP Sterne) erz{\"a}hlen uns etwas {\"u}ber die allerersten Sterne im Universum: sie haben relativ viel Kohlenstoff produziert. Wenn wir uns die genauen chemischen Fingerabdr{\"u}cke von CEMP Sterne angucken, erz{\"a}hlen sie uns noch viel mehr. Aber unsere Interpretation h{\"a}ngt von der Annahme ab, dass der chemische Fingerabdruck sich w{\"a}hrend des Lebens eines Sternes nicht ge{\"a}ndert hat. In dieser Dissertation werden neue Daten pr{\"a}sentiert die zeigen dass diese Annahme vielleicht zu einfach ist: viele extrem metallarme CEMP Sterne befinden sich in Doppelsternsystemen. Interaktion zwischen zwei Sternen in einem Doppelsternsystem k{\"o}nnte die Oberfl{\"a}che von CEMP Sternen verschmutzt haben. Zwar wurden die meisten CEMP Sterne h{\"o}chstwahrscheinlich nicht verschmutzt, aber wir sollten vorsichtig sein mit unserer Interpretation. Die CEMP Sterne und andere metallarme Sterne sind auch wichtig f{\"u}r unser Verst{\"a}ndnis der fr{\"u}hen Geschichte der Milchstraße. Die meisten Forscher, die metallarme Sterne studieren, suchen diese Sterne im Halo der Milchstraße: einer riesigen, diffuse Komponente die ungef{\"a}hr 1\% der Sterne in unserer Galaxie enth{\"a}lt. Modelle sagen aber vorher dass die {\"a}ltesten metallarmen Sterne sich im Zentrum der Milchstraße befinden (im „Bulge"). Das Zentrum ist leider, wegen großer Mengen Staub zwischen uns und dem Zentrum und einer {\"u}berw{\"a}ltigenden Mehrheit an metallreichen Sternen, schwierig zu beobachten. Diese Dissertation pr{\"a}sentiert Ergebnisse des „Pristine Inner Galaxy Survey" (PIGS), einer neuen Himmelsdurchmusterung, die die {\"a}ltesten Sterne im Bulge der Milchstraße sucht (und findet). PIGS benutzt Bilder mit einer Farbe, die f{\"u}r die Metallizit{\"a}t der Sterne empfindlich ist, und kann deswegen sehr effektiv die metallarmen Sterne aus Millionen anderer Sterne ausw{\"a}hlen. Von interessanten Kandidaten wurden Spektren aufgenommen und mit zwei unabh{\"a}ngigen Methoden analysiert. Mit dieser Strategie hat PIGS die bislang gr{\"o}ßte Anzahl an metallarmen Sternen in der inneren Galaxie entdeckt. Ein neues Ergebnis aus den PIGS Daten ist, dass die metall{\"a}rmeren Sterne langsamer um das Galaktische Zentrum drehen als die metallreichen Sterne, und dass sie mehr willk{\"u}rliche Bewegung zeigen. Eine zweite wichtige Leistung von PIGS ist die Entdeckung von dutzenden CEMP Sternen in der innere Galaxie, wo vorher nur zwei bekannt waren. Die neuen Ergebnisse aus dieser Dissertation helfen uns die ersten Sterne und die Geschichte der Milchstraße besser zu verstehen. Laufende und neue Himmelsdurchmusterungen in den n{\"a}chsten Jahren werden uns noch viel mehr Informationen geben: es ist eine aufregende Zeit f{\"u}r die Galaktische Arch{\"a}ologie.},
  language  = {en}
}
@phdthesis{Arya2020,
  author    = {Arya, Pooja},
  title     = {Light controlled active and passive motion of colloidal particles},
  doi       = {10.25932/publishup-48388},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-483880},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xvii, 183},
  year      = {2020},
  abstract  = {In this dissertation we introduce a concept of light driven active and passive manipulation of colloids trapped at solid/liquid interface. The motion is induced due to generation of light driven diffusioosmotic flow (LDDO) upon irradiation with light of appropriate wavelength. The origin of the flow is due to osmotic pressure gradient resulting from a concentration gradient at the solid/liquid interface of the photosensitive surfactant present in colloidal dispersion. The photosensitive surfactant consists of a cationic head group and a hydrophobic tail in which azobenzene group is integrated in. The azobenzene is known to undergo reversible photo-isomerization from a stable trans to a meta stable cis state under irradiation with UV light. Exposure to light of larger wavelength results in back photo-isomerization from cis to trans state. The two isomers have different molecular properties, for instance, trans isomer has a rod like structure and low polarity (0 dipole moment), whereas cis one is bent and has a dipole moment of ~3 Debye. Being integrated in the hydrophobic tail of the surfactant molecule, the azobenzene state determines the hydrophobicity of the whole molecule: in the trans state the surfactant is more hydrophobic than in the cis-state. In this way many properties of the surfactant such as the CMC, solubility and the interaction potential with a solid surface can be altered by light. When the solution containing such a surfactant is irradiated with focused light, a concentration gradient of different isomers is formed near the boundary of the irradiated area near the solid surface resulting in osmotic pressure gradient. The generated diffusioosmotic (DO) flow carries the particles passively along. The local-LDDO flow can be generated around and by each particle when mesoporous silica colloids are dispersed in the surfactant solution. This is because porous particles act as a sink/source which absorbs azobenzene molecule in trans state and expels it when it is in the cis state. The DO flows generated at each particle interact resulting in aggregation or separation depending upon the initial state of surfactant molecules. The kinetic of aggregation and separation can be controlled and manipulated by altering the parameters such as the wavelength and intensity of the applied light, as well as surfactant and particle concentration. Using two wavelengths simultaneously allows for dynamic gathering and separation creating fascinating patterns such as 2D disk of well separated particles or establishing collective complex behaviour of particle ensemble as described in this thesis. The mechanism of l-LDDO is also used to generate self-propelled motion. This is possible when half of the porous particle is covered by metal layer, basically blocking the pores on one side. The LDDO flow generated on uncapped side pushes the particle forward resulting in a super diffusive motion. The system of porous particle and azobenzene containing surfactant molecule can be utilized for various application such as drug delivery, cargo transportation, self-assembling, micro motors/ machines or micro patterning.},
  language  = {en}
}
@article{AryaFeldmannKopyshevetal.2020,
  author    = {Arya, Pooja and Feldmann, David and Kopyshev, Alexey and Lomadze, Nino and Santer, Svetlana},
  title     = {Light driven guided and self-organized motion of mesoporous colloidal particles},
  series = {Soft matter},
  volume    = {16},
  journal   = {Soft matter},
  number    = {5},
  publisher = {Royal Society of Chemistry},
  address   = {Cambridge},
  issn      = {1744-683X},
  doi       = {10.1039/c9sm02068c},
  pages     = {1148 -- 1155},
  year      = {2020},
  abstract  = {We report on guided and self-organized motion of ensembles of mesoporous colloidal particles that can undergo dynamic aggregation or separation upon exposure to light. The forces on particles involve the phenomenon of light-driven diffusioosmosis (LDDO) and are hydrodynamic in nature. They can be made to act passively on the ensemble as a whole but also used to establish a mutual interaction between particles. The latter scenario requires a porous colloid morphology such that the particle can act as a source or sink of a photosensitive surfactant, which drives the LDDO process. The interplay between the two modes of operation leads to fascinating possibilities of dynamical organization and manipulation of colloidal ensembles adsorbed at solid-liquid interfaces. While the passive mode can be thought of to allow for a coarse structuring of a cloud of colloids, the inter-particle mode may be used to impose a fine structure on a 2D particle grid. Local flow is used to impose and tailor interparticle interactions allowing for much larger interaction distances that can be achieved with, e.g., DLVO type of forces, and is much more versatile.},
  language  = {en}
}
@article{AryaJelkenFeldmannetal.2020,
  author    = {Arya, Pooja and Jelken, Joachim and Feldmann, David and Lomadze, Nino and Santer, Svetlana},
  title     = {Light driven diffusioosmotic repulsion and attraction of colloidal particles},
  series = {The journal of chemical physics : bridges a gap between journals of physics and journals of chemistr},
  volume    = {152},
  journal   = {The journal of chemical physics : bridges a gap between journals of physics and journals of chemistr},
  number    = {19},
  publisher = {American Institute of Physics},
  address   = {Melville, NY},
  issn      = {0021-9606},
  doi       = {10.1063/5.0007556},
  pages     = {10},
  year      = {2020},
  abstract  = {In this paper, we introduce the phenomenon of light driven diffusioosmotic long-range attraction and repulsion of porous particles under irradiation with UV light. The change in the inter-particle interaction potential is governed by flow patterns generated around single colloids and results in reversible aggregation or separation of the mesoporous silica particles that are trapped at a solid surface. The range of the interaction potential extends to several times the diameter of the particle and can be adjusted by varying the light intensity. The "fuel" of the process is a photosensitive surfactant undergoing photo-isomerization from a more hydrophobic trans-state to a rather hydrophilic cis-state. The surfactant has different adsorption affinities to the particles depending on the isomerization state. The trans-isomer, for example, tends to accumulate in the negatively charged pores of the particles, while the cis-isomer prefers to remain in the solution. This implies that when under UV irradiation cis-isomers are being formed within the pores, they tend to diffuse out readily and generate an excess concentration near the colloid's outer surface, ultimately resulting in the initiation of diffusioosmotic flow. The direction of the flow depends strongly on the dynamic redistribution of the fraction of trans- and cis-isomers near the colloids due to different kinetics of photo-isomerization within the pores as compared to the bulk. The unique feature of the mechanism discussed in the paper is that the long-range mutual repulsion but also the attraction can be tuned by convenient external optical stimuli such as intensity so that a broad variety of experimental situations for manipulation of a particle ensemble can be realized.},
  language  = {en}
}
@article{AryaJelkenLomadzeetal.2020,
  author    = {Arya, Pooja and Jelken, Joachim and Lomadze, Nino and Santer, Svetlana and Bekir, Marek},
  title     = {Kinetics of photo-isomerization of azobenzene containing surfactants},
  series = {The journal of chemical physics : bridges a gap between journals of physics and journals of chemistry},
  volume    = {152},
  journal   = {The journal of chemical physics : bridges a gap between journals of physics and journals of chemistry},
  number    = {2},
  publisher = {American Institute of Physics},
  address   = {Melville},
  issn      = {0021-9606},
  doi       = {10.1063/1.5135913},
  pages     = {10},
  year      = {2020},
  abstract  = {We report on photoisomerization kinetics of azobenzene containing surfactants in aqueous solution. The surfactant molecule consists of a positively charged trimethylammonium bromide head group, a hydrophobic spacer connecting via 6 to 10 CH2 groups to the azobenzene unit, and the hydrophobic tail of 1 and 3CH(2) groups. Under exposure to light, the azobenzene photoisomerizes from more stable trans- to metastable cis-state, which can be switched back either thermally in dark or by illumination with light of a longer wavelength. The surfactant isomerization is described by a kinetic model of a pseudo first order reaction approaching equilibrium, where the intensity controls the rate of isomerization until the equilibrated state. The rate constants of the trans-cis and cis-trans photoisomerization are calculated as a function of several parameters such as wavelength and intensity of light, the surfactant concentration, and the length of the hydrophobic tail. The thermal relaxation rate from cis- to trans-state is studied as well. The surfactant isomerization shows a different kinetic below and above the critical micellar concentration of the trans isomer due to steric hindrance within the densely packed micelle but does not depend on the spacer length.},
  language  = {en}
}
@phdthesis{Aseev2020,
  author    = {Aseev, Nikita},
  title     = {Modeling and understanding dynamics of charged particles in the Earth's inner magnetosphere},
  doi       = {10.25932/publishup-47921},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-479211},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xxii, 154},
  year      = {2020},
  abstract  = {The Earth's inner magnetosphere is a very dynamic system, mostly driven by the external solar wind forcing exerted upon the magnetic field of our planet. Disturbances in the solar wind, such as coronal mass ejections and co-rotating interaction regions, cause geomagnetic storms, which lead to prominent changes in charged particle populations of the inner magnetosphere - the plasmasphere, ring current, and radiation belts. Satellites operating in the regions of elevated energetic and relativistic electron fluxes can be damaged by deep dielectric or surface charging during severe space weather events. Predicting the dynamics of the charged particles and mitigating their effects on the infrastructure is of particular importance, due to our increasing reliance on space technologies. The dynamics of particles in the plasmasphere, ring current, and radiation belts are strongly coupled by means of collisions and collisionless interactions with electromagnetic fields induced by the motion of charged particles. Multidimensional numerical models simplify the treatment of transport, acceleration, and loss processes of these particles, and allow us to predict how the near-Earth space environment responds to solar storms. The models inevitably rely on a number of simplifications and assumptions that affect model accuracy and complicate the interpretation of the results. In this dissertation, we quantify the processes that control electron dynamics in the inner magnetosphere, paying particular attention to the uncertainties of the employed numerical codes and tools. We use a set of convenient analytical solutions for advection and diffusion equations to test the accuracy and stability of the four-dimensional Versatile Electron Radiation Belt (VERB-4D) code. We show that numerical schemes implemented in the code converge to the analytical solutions and that the VERB-4D code demonstrates stable behavior independent of the assumed time step. The order of the numerical scheme for the convection equation is demonstrated to affect results of ring current and radiation belt simulations, and it is crucially important to use high-order numerical schemes to decrease numerical errors in the model. Using the thoroughly tested VERB-4D code, we model the dynamics of the ring current electrons during the 17 March 2013 storm. The discrepancies between the model and observations above 4.5 Earth's radii can be explained by uncertainties in the outer boundary conditions. Simulation results indicate that the electrons were transported from the geostationary orbit towards the Earth by the global-scale electric and magnetic fields. We investigate how simulation results depend on the input models and parameters. The model is shown to be particularly sensitive to the global electric field and electron lifetimes below 4.5 Earth's radii. The effects of radial diffusion and subauroral polarization streams are also quantified. We developed a data-assimilative code that blends together a convection model of energetic electron transport and loss and Van Allen Probes satellite data by means of the Kalman filter. We show that the Kalman filter can correct model uncertainties in the convection electric field, electron lifetimes, and boundary conditions. It is also demonstrated how the innovation vector - the difference between observations and model prediction - can be used to identify physical processes missing in the model of energetic electron dynamics. We computed radial profiles of phase space density of ultrarelativistic electrons, using Van Allen Probes measurements. We analyze the shape of the profiles during geomagnetically quiet and disturbed times and show that the formation of new local minimums in the radial profiles coincides with the ground observations of electromagnetic ion-cyclotron (EMIC) waves. This correlation indicates that EMIC waves are responsible for the loss of ultrarelativistic electrons from the heart of the outer radiation belt into the Earth's atmosphere.},
  language  = {en}
}
@article{AssagraAltafimdoCarmoetal.2020,
  author    = {Assagra, Yuri A.O. and Altafim, Ruy Alberto Pisani and do Carmo, Joao P. and Altafim, Ruy A.C. and Rychkov, Dmitry and Wirges, Werner and Gerhard, Reimund},
  title     = {A new route to piezo-polymer transducers: 3D printing of polypropylene ferroelectrets},
  series = {IEEE transactions on dielectrics and electrical insulation},
  volume    = {27},
  journal   = {IEEE transactions on dielectrics and electrical insulation},
  number    = {5},
  publisher = {Inst. of Electr. and Electronics Engineers},
  address   = {Piscataway},
  issn      = {1070-9878},
  doi       = {10.1109/TDEI.2020.008461},
  pages     = {1668 -- 1674},
  year      = {2020},
  abstract  = {Here, a promising approach for producing piezo-polymer transducers in a one-step process is presented. Using 3D-printing technology and polypropylene (PP) filaments, we are able to print a two-layered film structure with regular cavities of precisely controlled size and shape. It is found that the 3D-printed samples exhibit piezoelectric coefficients up to 200 pC/N, similar to those of other PP ferroelectrets, and their temporal and thermal behavior is in good agreement with those known of PP ferroelectrets. The piezoelectric response strongly decreases for applied pressures above 20 kPa, as the pressure in the air-filled cavities strongly influences the overall elastic modulus of ferroelectrets.},
  language  = {en}
}
@article{AwadMetzler2020,
  author    = {Awad, Emad and Metzler, Ralf},
  title     = {Crossover dynamics from superdiffusion to subdiffusion},
  series = {Fractional calculus and applied analysis : an international journal for theory and applications},
  volume    = {23},
  journal   = {Fractional calculus and applied analysis : an international journal for theory and applications},
  number    = {1},
  publisher = {De Gruyter},
  address   = {Berlin ; Boston},
  issn      = {1311-0454},
  doi       = {10.1515/fca-2020-0003},
  pages     = {55 -- 102},
  year      = {2020},
  abstract  = {The Cattaneo or telegrapher's equation describes the crossover from initial ballistic to normal diffusion. Here we study and survey time-fractional generalisations of this equation that are shown to produce the crossover of the mean squared displacement from superdiffusion to subdiffusion. Conditional solutions are derived in terms of Fox H-functions and the dth-order moments as well as the diffusive flux of the different models are derived. Moreover, the concept of the distribution-like is proposed as an alternative to the probability density function.},
  language  = {en}
}
@misc{BetaGovYochelis2020,
  author    = {Beta, Carsten and Gov, Nir S. and Yochelis, Arik},
  title     = {Why a Large-Scale Mode Can Be Essential for Understanding Intracellular Actin Waves},
  series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  number    = {967},
  issn      = {1866-8372},
  doi       = {10.25932/publishup-47358},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-473588},
  pages     = {20},
  year      = {2020},
  abstract  = {During the last decade, intracellular actin waves have attracted much attention due to their essential role in various cellular functions, ranging from motility to cytokinesis. Experimental methods have advanced significantly and can capture the dynamics of actin waves over a large range of spatio-temporal scales. However, the corresponding coarse-grained theory mostly avoids the full complexity of this multi-scale phenomenon. In this perspective, we focus on a minimal continuum model of activator-inhibitor type and highlight the qualitative role of mass conservation, which is typically overlooked. Specifically, our interest is to connect between the mathematical mechanisms of pattern formation in the presence of a large-scale mode, due to mass conservation, and distinct behaviors of actin waves.},
  language  = {en}
}
@article{BetaGovYochelis2020,
  author    = {Beta, Carsten and Gov, Nir S. and Yochelis, Arik},
  title     = {Why a Large-Scale Mode Can Be Essential for Understanding Intracellular Actin Waves},
  series = {Cells},
  volume    = {9},
  journal   = {Cells},
  number    = {6},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {2073-4409},
  doi       = {10.3390/cells9061533},
  pages     = {18},
  year      = {2020},
  abstract  = {During the last decade, intracellular actin waves have attracted much attention due to their essential role in various cellular functions, ranging from motility to cytokinesis. Experimental methods have advanced significantly and can capture the dynamics of actin waves over a large range of spatio-temporal scales. However, the corresponding coarse-grained theory mostly avoids the full complexity of this multi-scale phenomenon. In this perspective, we focus on a minimal continuum model of activator-inhibitor type and highlight the qualitative role of mass conservation, which is typically overlooked. Specifically, our interest is to connect between the mathematical mechanisms of pattern formation in the presence of a large-scale mode, due to mass conservation, and distinct behaviors of actin waves.},
  language  = {en}
}
@article{Bouakline2020,
  author    = {Bouakline, Foudhil},
  title     = {Does nuclear permutation symmetry allow dynamical localization in symmetric double-well achiral molecules?},
  series = {The journal of chemical physics : bridges a gap between journals of physics and journals of chemistr},
  volume    = {152},
  journal   = {The journal of chemical physics : bridges a gap between journals of physics and journals of chemistr},
  number    = {24},
  publisher = {American Institute of Physics},
  address   = {Melville},
  issn      = {0021-9606},
  doi       = {10.1063/1.5141746},
  pages     = {17},
  year      = {2020},
  abstract  = {We discuss the effect of molecular symmetry on coherent tunneling in symmetric double-well potentials whose two molecular equilibrium configurations are interconverted by nuclear permutations. This is illustrated with vibrational tunneling in ammonia molecules, electronic tunneling in the dihydrogen cation, and laser-induced rotational tunneling of homonuclear diatomics. In this contribution, we reexamine the textbook picture of coherent tunneling in such potentials, which is depicted with a wavepacket shuttling back and forth between the two potential-wells. We show that the common application of this picture to the aforementioned molecules contravenes the principle of the indistinguishability of identical particles. This conflict originates from the sole consideration of the dynamics of the tunneling-mode, connecting the double-well energy minima, and complete omission of all the remaining molecular degrees of freedom. This gives rise to double-well wavepackets that are nonsymmetric under nuclear permutations. To obey quantum statistics, we show that the double-well eigenstates composing these wavepackets must be entangled with the wavefunctions that describe all the omitted molecular modes. These wavefunctions have compensating and opposite nuclear permutation symmetry. This in turn leads to complete quenching of interference effects behind localization in one potential-well or another. Indeed, we demonstrate that the reduced density of probability of the symmetrized molecular wavefunction, where all the molecular coordinates but the tunneling-mode are integrated out, is symmetrically distributed over the two potential-wells, at all times. This applies to any multilevel wavepacket of isotropic or fully aligned symmetric double-well achiral molecules. However, in the case of coherent electronic or vibrational tunneling, fully aligned molecules may exhibit dynamical localization in the space-fixed frame, where the tunneling-mode density shuttles between the opposite directions of the alignment axis. This dynamical spatial-localization results from linear combinations of molecular states that have opposite parity. In summary, this study shows that dynamical localization of the tunneling-mode density on either of the two indistinguishable molecular equilibrium configurations of symmetric double-well achiral molecules is forbidden by quantum statistics, whereas its dynamical localization in the space-fixed frame is allowed by parity. The subtle distinction between these two types of localization has far-reaching implications in the interpretation of many ultrafast molecular dynamics experiments.},
  language  = {en}
}
@book{Brehmer2020,
  author    = {Brehmer, Ludwig},
  title     = {70-j{\"a}hriges-Jubil{\"a}um der Gr{\"u}ndung der Hochschul-Biologie und des Botanischen Gartens der P{\"a}dagogischen Hochschule Potsdam},
  series = {Die Hochschulstadt in Sanssouci ; Band 8},
  journal   = {Die Hochschulstadt in Sanssouci ; Band 8},
  publisher = {Eigenverlag des Verfassers Brehmer},
  address   = {Schwielowsee},
  isbn      = {978-3-9821787-3-8},
  pages     = {183},
  year      = {2020},
  language  = {de}
}