@phdthesis{Liepertz2017,
  author    = {Liepertz, Sven Christian},
  title     = {Zusammenhang zwischen dem Professionswissen von Physiklehrkr{\"a}ften, dem sachstrukturellen Angebot des Unterrichts und der Sch{\"u}lerleistung},
  series = {Studien zum Physik- und Chemielernen ; 224},
  journal   = {Studien zum Physik- und Chemielernen ; 224},
  publisher = {Logos},
  address   = {Berlin},
  isbn      = {978-3-8325-4480-5},
  school      = {Universit{\"a}t Potsdam},
  pages     = {133},
  year      = {2017},
  language  = {de}
}
@article{LeussuUsoskinValliappanetal.2017,
  author    = {Leussu, R. and Usoskin, IIlya G. and Valliappan, Senthamizh Pavai and Diercke, Andrea and Arlt, Rainer and Denker, Carsten and Mursula, K.},
  title     = {Wings of the butterfly},
  series = {Astronomy and astrophysics : an international weekly journal},
  volume    = {599},
  journal   = {Astronomy and astrophysics : an international weekly journal},
  publisher = {EDP Sciences},
  address   = {Les Ulis},
  issn      = {1432-0746},
  doi       = {10.1051/0004-6361/201629533},
  pages     = {8},
  year      = {2017},
  abstract  = {The spatio-temporal evolution of sunspot activity, the so-called Maunder butterfly diagram, has been continously available since 1874 using data from the Royal Greenwich Observatory, extended by SOON network data after 1976. Here we present a new extended butterfly diagram of sunspot group occurrence since 1826, using the recently digitized data from Schwabe (1826-1867) and Sporer (1866-1880). The wings of the diagram are separated using a recently developed method based on an analysis of long gaps in sunspot group occurrence in different latitude bands. We define characteristic latitudes, corresponding to the start, end, and the largest extent of the wings (the F, L, and H latitudes). The H latitudes (30 degrees-45 degrees) are highly significantly correlated with the strength of the wings (quantified by the total sum of the monthly numbers of sunspot groups). The F latitudes (20 degrees-30 degrees) depict a weak tendency, especially in the southern hemisphere, to follow the wing strength. The L latitudes (2 degrees-10 degrees) show no clear relation to the wing strength. Overall, stronger cycle wings tend to start at higher latitudes and have a greater wing extent. A strong (5-6)-cycle periodic oscillation is found in the start and end times of the wings and in the overlap and gaps between successive wings of one hemisphere. While the average wing overlap is zero in the southern hemisphere, it is two to three months in the north. A marginally significant oscillation of about ten solar cycles is found in the asymmetry of the L latitudes. The new long database of butterfly wings provides new observational constraints to solar dynamo models that discuss the spatio-temporal distribution of sunspot occurrence over the solar cycle and longer.},
  language  = {en}
}
@phdthesis{Kayser2017,
  author    = {Kayser, Markus},
  title     = {Wechselwirkung der atmosph{\"a}rischen Grenzschicht mit synoptisch-skaligen Prozessen w{\"a}hrend der N-ICE2015 Kampagne},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-411124},
  school      = {Universit{\"a}t Potsdam},
  pages     = {147},
  year      = {2017},
  abstract  = {Die Arktis erw{\"a}rmt sich schneller als der Rest der Erde. Die Auswirkungen manifestieren sich unter Anderem in einer verst{\"a}rkten Erw{\"a}rmung der arktischen Grenzschicht. Diese Arbeit befasst sich mit Wechselwirkungen zwischen synoptischen Zyklonen und der arktischen Atmosph{\"a}re auf lokalen bis {\"u}berregionalen Skalen. Ausgangspunkt daf{\"u}r sind Messdaten und Modellsimulationen f{\"u}r den Zeitraum der N-ICE2015 Expedition, die von Anfang Januar bis Ende Juni 2015 im arktischen Nordatlantiksektor stattgefunden hat. Anhand von Radiosondenmessungen lassen sich Auswirkungen von synoptischen Zyklonen am deutlichsten im Winter erkennen, da sie durch die Advektion warmer und feuchter Luftmassen in die Arktis den Zustand der Atmosph{\"a}re von einem strahlungs-klaren in einen strahlungs-opaken {\"a}ndern. Obwohl dieser scharfe Kontrast nur im Winter existiert, zeigt die Analyse, dass der integrierte Wasserdampf als Indikator f{\"u}r die Advektion von Luftmassen aus niedrigen Breiten in die Arktis auch im Fr{\"u}hjahr geeignet ist. Neben der Advektion von Luftmassen wird der Einfluss der Zyklonen auf die statische Stabilit{\"a}t charakterisiert. Beim Vergleich der N-ICE2015 Beobachtungen mit der SHEBA Kampagne (1997/1998), die {\"u}ber dickerem Eis stattfand, finden sich trotz der unterschiedlichen Meereisregime {\"A}hnlichkeiten in der statischen Stabilit{\"a}t der Atmosph{\"a}re. Die beobachteten Differenzen in der Stabilit{\"a}t lassen sich auf Unterschiede in der synoptischen Aktivit{\"a}t zur{\"u}ckf{\"u}hren. Dies l{\"a}sst vermuten, dass die d{\"u}nnere Eisdecke auf saisonalen Zeitskalen nur einen geringen Einfluss auf die thermodynamische Struktur der arktischen Troposph{\"a}re besitzt, solange eine dicke Schneeschicht sie bedeckt. Ein weiterer Vergleich mit den parallel zur N-ICE2015 Kampagne gestarteten Radiosonden der AWIPEV Station in Ny-{\AA}esund, Spitzbergen, macht deutlich, dass die synoptischen Zyklonen oberhalb der Orographie auf saisonalen Zeitskalen das Wettergeschehen bestimmen. Des Weiteren werden f{\"u}r Februar 2015 die Auswirkungen von in der Vertikalen variiertem Nudging auf die Entwicklung der Zyklonen am Beispiel des hydrostatischen regionalen Klimamodells HIRHAM5 untersucht. Es zeigt sich, dass die Unterschiede zwischen den acht Modellsimulationen mit abnehmender Anzahl der genudgten Level zunehmen. Die gr{\"o}ßten Differenzen resultieren vornehmlich aus dem zeitlichen Versatz der Entwicklung synoptischer Zyklonen. Zur Korrektur des Zeitversatzes der Zykloneninitiierung gen{\"u}gt es bereits, Nudging in den unterstem 250 m der Troposph{\"a}re anzuwenden. Daneben findet sich zwischen den genudgten HIRHAM5-Simulation und den in situ Messungen der gleiche positive Temperaturbias, den auch ERA-Interim besitzt. Das freie HIRHAM hingegen reproduziert das positive Ende der N-ICE2015 Temperaturverteilung gut, besitzt aber einen starken negativen Bias, der sehr wahrscheinlich aus einer Untersch{\"a}tzung des Feuchtegehalts resultiert. An Beispiel einer Zyklone wird gezeigt, dass Nudging Einfluss auf die Lage der H{\"o}hentiefs besitzt, die ihrerseits die Zyklonenentwicklung am Boden beeinflussen. Im Weiteren wird mittels eines f{\"u}r kleine Ensemblegr{\"o}ßen geeigneten Varianzmaßes eine statistische Einsch{\"a}tzung der Wirkung des Nudgings auf die Vertikale getroffen. Es wird festgestellt, dass die {\"A}hnlichkeit der Modellsimulationen in der unteren Troposph{\"a}re generell h{\"o}her ist als dar{\"u}ber und in 500 hPa ein lokales Minimum besitzt. Im letzten Teil der Analyse wird die Wechselwirkung der oberen und unteren Stratosph{\"a}re anhand zuvor betrachteter Zyklonen mit Daten der ERA-Interim Reanalyse untersucht. Lage und Ausrichtung des Polarwirbels erzeugten ab Anfang Februar 2015 eine ungew{\"o}hnlich große Meridionalkomponente des Tropopausenjets, die Zugbahnen in die zentrale Arktis beg{\"u}nstigte. Am Beispiel einer Zyklone wird die {\"U}bereinstimmung der synoptischen Entwicklung mit den theoretischen Annahmen {\"u}ber den abw{\"a}rts gerichteten Einfluss der Stratosph{\"a}re auf die Troposph{\"a}re hervorgehoben. Dabei spielt die nicht-lineare Wechselwirkung zwischen der Orographie Gr{\"o}nlands, einer Intrusion stratosph{\"a}rischer Luft in die Troposph{\"a}re sowie einer in Richtung Arktis propagierender Rossby-Welle eine tragende Rolle. Als Indikator dieser Wechselwirkung werden horizontale Signaturen aus abwechselnd aufsteigender und absinkender Luft innerhalb der Troposph{\"a}re identifiziert.},
  language  = {de}
}
@article{KayserMaturilliGrahametal.2017,
  author    = {Kayser, Markus and Maturilli, Marion and Graham, Robert M. and Hudson, Stephen R. and Rinke, Annette and Cohen, Lana and Kim, Joo-Hong and Park, Sang-Jong and Moon, Woosok and Granskog, Mats A.},
  title     = {Vertical thermodynamic structure of the troposphere during the Norwegian young sea ICE expedition (N-ICE2015)},
  series = {Journal of geophysical research-atmosheres},
  volume    = {122},
  journal   = {Journal of geophysical research-atmosheres},
  number    = {20},
  publisher = {American Geophysical Union},
  address   = {Washington},
  issn      = {2169-897X},
  doi       = {10.1002/2016JD026089},
  pages     = {10855 -- 10872},
  year      = {2017},
  abstract  = {The Norwegian young sea ICE (N-ICE2015) expedition was designed to investigate the atmosphere-snow-ice-ocean interactions in the young and thin sea ice regime north of Svalbard. Radiosondes were launched twice daily during the expedition from January to June 2015. Here we use these upper air measurements to study the multiple cyclonic events observed during N-ICE2015 with respect to changes in the vertical thermodynamic structure, moisture content, and boundary layer characteristics. We provide statistics of temperature inversion characteristics, static stability, and boundary layer extent. During winter, when radiative cooling is most effective, we find the strongest impact of synoptic cyclones. Changes to thermodynamic characteristics of the boundary layer are associated with transitions between the radiatively "clear" and "opaque" atmospheric states. In spring, radiative fluxes warm the surface leading to lifted temperature inversions and a statically unstable boundary layer. Further, we compare the N-ICE2015 static stability distributions to corresponding profiles from ERA-Interim reanalysis, from the closest land station in the Arctic North Atlantic sector, Ny-Alesund, and to soundings from the SHEBA expedition (1997/1998). We find similar stability characteristics for N-ICE2015 and SHEBA throughout the troposphere, despite differences in location, sea ice thickness, and snow cover. For Ny-Alesund, we observe similar characteristics above 1000 m, while the topography and ice-free fjord surrounding Ny-Alesund generate great differences below. The long-term radiosonde record (1993-2014) from Ny-Alesund indicates that during the N-ICE2015 spring period, temperatures were close to the climatological mean, while the lowest 3000 m were 1-3 degrees C warmer than the climatology during winter. Plain Language Summary The Norwegian young sea ICE (N-ICE2015) expedition was designed to investigate the atmosphere-snow-ice-ocean interactions in the young and thin sea ice regime north of Svalbard. Radiosondes were launched twice daily during the expedition from January to June 2015. Here we use these upper air measurements to study the multiple cyclonic events observed during N-ICE2015 with respect to changes in the vertical thermodynamic structure, moisture content, and the atmospheric boundary layer characteristics. During winter, we find the strongest impact of synoptic cyclones, which transport warm and moist air into the cold and dry Arctic atmosphere. In spring, incoming solar radiation warms the surface. This leads to very different thermodynamic conditions and higher moisture content, which reduces the contrast between stormy and calm periods. Further, we compare the N-ICE2015 measurements to corresponding profiles from ERA-Interim reanalysis, from the closest land station in the Arctic North Atlantic sector, Ny-Alesund, and to soundings from the SHEBA expedition (1997/1998). We find similar stability characteristics for N-ICE2015 and SHEBA throughout the troposphere, despite differences in location, sea ice thickness, and snow cover. The comparisons highlight the value of the N-ICE2015 observation and show the importance of winter time observations in the Arctic North Atlantic sector.},
  language  = {en}
}
@misc{FraschettiPohl2017,
  author    = {Fraschetti, Federico and Pohl, Martin},
  title     = {Two-zone model for the broadband crab nebula spectrum},
  series = {The European physical journal : Web of Conferences : proceedings},
  volume    = {136},
  journal   = {The European physical journal : Web of Conferences : proceedings},
  publisher = {EDP Sciences},
  address   = {Les Ulis},
  issn      = {2100-014X},
  doi       = {10.1051/epjconf/201713602009},
  pages     = {5},
  year      = {2017},
  abstract  = {We develop a simple two-zone interpretation of the broadband baseline Crab nebula spectrum between 10(-5) eV and similar to 100 TeV by using two distinct log-parabola energetic electrons distributions. We determine analytically the very-high energy photon spectrum as originated by inverse-Compton scattering of the far-infrared soft ambient photons within the nebula off a first population of electrons energized at the nebula termination shock. The broad and flat 200 GeV peak jointly observed by Fermi/LAT and MAGIC is naturally reproduced. The synchrotron radiation from a second energetic electron population explains the spectrum from the radio range up to similar to 10 keV. We infer from observations the energy dependence of the microscopic probability of remaining in proximity of the shock of the accelerating electrons.},
  language  = {en}
}
@article{SchubertFrischAllardetal.2017,
  author    = {Schubert, Marcel and Frisch, Johannes and Allard, Sybille and Preis, Eduard and Scherf, Ullrich and Koch, Norbert and Neher, Dieter},
  title     = {Tuning side chain and main chain order in a prototypical donor-acceptor copolymer},
  series = {Elementary Processes in Organic Photovoltaics},
  volume    = {272},
  journal   = {Elementary Processes in Organic Photovoltaics},
  publisher = {Springer},
  address   = {Berlin},
  isbn      = {978-3-319-28338-8},
  issn      = {0065-3195},
  doi       = {10.1007/978-3-319-28338-8_10},
  pages     = {243 -- 265},
  year      = {2017},
  abstract  = {The recent development of donor-acceptor copolymers has led to an enormous improvement in the performance of organic solar cells and organic field-effect transistors. Here we describe the synthesis, detailed characterisation, and application of a series of structurally modified copolymers to investigate fundamental structure-property relationships in this class of conjugated polymers. The interplay between chemical structure and optoelectronic properties is investigated. These are further correlated to the charge transport and solar cell performance, which allows us to link their chemical structure to the observed physical properties.},
  language  = {en}
}
@article{CherstvyVinodAghionetal.2017,
  author    = {Cherstvy, Andrey G. and Vinod, Deepak and Aghion, Erez and Chechkin, Aleksei V. and Metzler, Ralf},
  title     = {Time averaging, ageing and delay analysis of financial time series},
  series = {New journal of physics},
  volume    = {19},
  journal   = {New journal of physics},
  publisher = {IOP},
  address   = {London},
  issn      = {1367-2630},
  doi       = {10.1088/1367-2630/aa7199},
  pages     = {1 -- 11},
  year      = {2017},
  abstract  = {We introduce three strategies for the analysis of financial time series based on time averaged observables. These comprise the time averaged mean squared displacement (MSD) as well as the ageing and delay time methods for varying fractions of the financial time series. We explore these concepts via statistical analysis of historic time series for several Dow Jones Industrial indices for the period from the 1960s to 2015. Remarkably, we discover a simple universal law for the delay time averaged MSD. The observed features of the financial time series dynamics agree well with our analytical results for the time averaged measurables for geometric Brownian motion, underlying the famed Black-Scholes-Merton model. The concepts we promote here are shown to be useful for financial data analysis and enable one to unveil new universal features of stock market dynamics.},
  language  = {en}
}
@misc{CherstvyVinodAghionetal.2017,
  author    = {Cherstvy, Andrey G. and Vinod, Deepak and Aghion, Erez and Chechkin, Aleksei V. and Metzler, Ralf},
  title     = {Time averaging, ageing and delay analysis of financial time series},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-400541},
  pages     = {11},
  year      = {2017},
  abstract  = {We introduce three strategies for the analysis of financial time series based on time averaged observables. These comprise the time averaged mean squared displacement (MSD) as well as the ageing and delay time methods for varying fractions of the financial time series. We explore these concepts via statistical analysis of historic time series for several Dow Jones Industrial indices for the period from the 1960s to 2015. Remarkably, we discover a simple universal law for the delay time averaged MSD. The observed features of the financial time series dynamics agree well with our analytical results for the time averaged measurables for geometric Brownian motion, underlying the famed Black-Scholes-Merton model. The concepts we promote here are shown to be useful for financial data analysis and enable one to unveil new universal features of stock market dynamics.},
  language  = {en}
}
@article{SundeGrijsSubramanianetal.2017,
  author    = {Sun, Ning-Chen and de Grijs, Richard and Subramanian, Smitha and Cioni, Maria-Rosa L. and Rubele, Stefano and Bekki, Kenji and Ivanov, Valentin D. and Piatti, Andr{\´e}s E. and Ripepi, Vincenzo},
  title     = {The VMC Survey. XXII. Hierarchical star formation in the 30 Doradus-N158-N159-N160 star-forming complex},
  series = {The astrophysical journal : an international review of spectroscopy and astronomical physics},
  volume    = {835},
  journal   = {The astrophysical journal : an international review of spectroscopy and astronomical physics},
  number    = {2},
  publisher = {Institute of Physics Publ.},
  address   = {Bristol},
  issn      = {0004-637X},
  doi       = {10.3847/1538-4357/835/2/171},
  pages     = {10},
  year      = {2017},
  abstract  = {We study the hierarchical stellar structures in a similar to 1.5 deg(2) area covering the 30. Doradus-N158-N159-N160 starforming complex with the VISTA Survey of. Magellanic Clouds. Based on the young upper main-sequence stars, we find that the surface densities cover a wide range of values, from log(Sigma.pc(2))less than or similar to -2.0 to log(Sigma. pc(2)) greater than or similar to 0.0. Their distributions are highly non-uniform, showing groups that frequently have subgroups inside. The sizes of the stellar groups do not exhibit characteristic values, and range continuously from several parsecs to more than 100. pc; the cumulative size distribution can be well described by a single power law, with the power-law index indicating a projected fractal dimension D-2 = 1.6 +/- 0.3. We suggest that the phenomena revealed here support a scenario of hierarchical star formation. Comparisons with other star-forming regions and galaxies are also discussed.},
  language  = {en}
}
@article{AlmeidaSanaTayloretal.2017,
  author    = {Almeida, Leonardo A. and Sana, H. and Taylor, W. and Barb{\´a}, Rodolfo and Bonanos, Alceste Z. and Crowther, Paul and Damineli, Augusto and de Koter, A. and de Mink, Selma E. and Evans, C. J. and Gieles, Mark and Grin, Nathan J. and H{\´e}nault-Brunet, V. and Langer, Norbert and Lennon, D. and Lockwood, Sean and Ma{\´i}z Apell{\´a}niz, Jes{\´u}s and Moffat, A. F. J. and Neijssel, C. and Norman, C. and Ram{\´i}rez-Agudelo, O. H. and Richardson, N. D. and Schootemeijer, Abel and Shenar, Tomer and Soszyński, Igor and Tramper, Frank and Vink, J. S.},
  title     = {The tarantula massive binary monitoring},
  series = {Astronomy and astrophysics : an international weekly journal},
  volume    = {598},
  journal   = {Astronomy and astrophysics : an international weekly journal},
  publisher = {EDP Sciences},
  address   = {Les Ulis},
  issn      = {1432-0746},
  doi       = {10.1051/0004-6361/201629844},
  pages     = {36},
  year      = {2017},
  abstract  = {Context: Massive binaries play a crucial role in the Universe. Knowing the distributions of their orbital parameters is important for a wide range of topics from stellar feedback to binary evolution channels and from the distribution of supernova types to gravitational wave progenitors, yet no direct measurements exist outside the Milky Way. Aims: The Tarantula Massive Binary Monitoring project was designed to help fill this gap by obtaining multi-epoch radial velocity (RV) monitoring of 102 massive binaries in the 30 Doradus region. Methods: In this paper we analyze 32 FLAMES/GIRAFFE observations of 93 O- and 7 B-type binaries. We performed a Fourier analysis and obtained orbital solutions for 82 systems: 51 single-lined (SB1) and 31 double-lined (SB2) spectroscopic binaries. Results: Overall, the binary fraction and orbital properties across the 30 Doradus region are found to be similar to existing Galactic samples. This indicates that within these domains environmental effects are of second order in shaping the properties of massive binary systems. A small difference is found in the distribution of orbital periods, which is slightly flatter (in log space) in 30 Doradus than in the Galaxy, although this may be compatible within error estimates and differences in the fitting methodology. Also, orbital periods in 30 Doradus can be as short as 1.1 d, somewhat shorter than seen in Galactic samples. Equal mass binaries (q> 0.95) in 30 Doradus are all found outside NGC 2070, the central association that surrounds R136a, the very young and massive cluster at 30 Doradus's core. Most of the differences, albeit small, are compatible with expectations from binary evolution. One outstanding exception, however, is the fact that earlier spectral types (O2-O7) tend to have shorter orbital periods than later spectral types (O9.2-O9.7). Conclusions: Our results point to a relative universality of the incidence rate of massive binaries and their orbital properties in the metallicity range from solar (Z⊙) to about half solar. This provides the first direct constraints on massive binary properties in massive star-forming galaxies at the Universe's peak of star formation at redshifts z ~ 1 to 2 which are estimated to have Z ~ 0.5 Z⊙.},
  language  = {en}
}