@article{LevermannWinkelmann2016,
  author    = {Levermann, Anders and Winkelmann, Ricarda},
  title     = {A simple equation for the melt elevation feedback of ice sheets},
  series = {The Cryosphere : TC ; an interactive open access journal of the European Geosciences Union},
  volume    = {10},
  journal   = {The Cryosphere : TC ; an interactive open access journal of the European Geosciences Union},
  publisher = {Copernicus},
  address   = {G{\"o}ttingen},
  issn      = {1994-0416},
  doi       = {10.5194/tc-10-1799-2016},
  pages     = {1799 -- 1807},
  year      = {2016},
  abstract  = {In recent decades, the Greenland Ice Sheet has been losing mass and has thereby contributed to global sea-level rise. The rate of ice loss is highly relevant for coastal protection worldwide. The ice loss is likely to increase under future warming. Beyond a critical temperature threshold, a meltdown of the Greenland Ice Sheet is induced by the self-enforcing feedback between its lowering surface elevation and its increasing surface mass loss: the more ice that is lost, the lower the ice surface and the warmer the surface air temperature, which fosters further melting and ice loss. The computation of this rate so far relies on complex numerical models which are the appropriate tools for capturing the complexity of the problem. By contrast we aim here at gaining a conceptual understanding by deriving a purposefully simple equation for the self-enforcing feedback which is then used to estimate the melt time for different levels of warming using three observable characteristics of the ice sheet itself and its surroundings. The analysis is purely conceptual in nature. It is missing important processes like ice dynamics for it to be useful for applications to sea-level rise on centennial timescales, but if the volume loss is dominated by the feedback, the resulting logarithmic equation unifies existing numerical simulations and shows that the melt time depends strongly on the level of warming with a critical slow-down near the threshold: the median time to lose 10\% of the present-day ice volume varies between about 3500 years for a temperature level of 0.5 degrees C above the threshold and 500 years for 5 degrees C. Unless future observations show a significantly higher melting sensitivity than currently observed, a complete meltdown is unlikely within the next 2000 years without significant ice-dynamical contributions.},
  language  = {en}
}
@article{CohenCampisanoArrowsmithetal.2016,
  author    = {Cohen, Andrew and Campisano, C. and Arrowsmith, J. Ram{\´o}n and Asrat, Asfawossen and Behrensmeyer, A. K. and Deino, A. and Feibel, C. and Hill, A. and Johnson, R. and Kingston, J. and Lamb, Henry F. and Lowenstein, T. and Noren, A. and Olago, D. and Owen, R. B. and Potts, R. and Reed, Kate and Renaut, R. and Sch{\"a}bitz, Frank and Tiercelin, J. -J. and Trauth, Martin H. and Wynn, J. and Ivory, S. and Brady, K. and Rodysill, J. and Githiri, J. and Russell, J. and F{\"o}rster, Verena and Dommain, Ren{\´e} and Rucina, S. and Deocampo, D. and Russell, J. and Billingsley, A. and Beck, C. and Dorenbeck, G. and Dullo, L. and Feary, D. and Garello, D. and Gromig, R. and Johnson, T. and Junginger, A. and Karanja, M. and Kimburi, E. and Mbuthia, A. and McCartney, T. and McNulty, E. and Muiruri, V. and Nambiro, E. and Negash, E. W. and Njagi, D. and Wilson, J. N. and Rabideaux, N. and Raub, T. and Sier, M. J. and Smith, P. and Urban, J. and Warren, M. and Yadeta, M. and Yost, C. and Zinaye, B.},
  title     = {The Hominin Sites and Paleolakes Drilling Project: inferring the environmental context of human evolution from eastern African rift lake deposits},
  series = {Scientific Drilling},
  volume    = {21},
  journal   = {Scientific Drilling},
  publisher = {Copernicus},
  address   = {G{\"o}ttingen},
  issn      = {1816-8957},
  doi       = {10.5194/sd-21-1-2016},
  pages     = {1 -- 16},
  year      = {2016},
  abstract  = {The role that climate and environmental history may have played in influencing human evolution has been the focus of considerable interest and controversy among paleoanthropologists for decades. Prior attempts to understand the environmental history side of this equation have centered around the study of outcrop sediments and fossils adjacent to where fossil hominins (ancestors or close relatives of modern humans) are found, or from the study of deep sea drill cores. However, outcrop sediments are often highly weathered and thus are unsuitable for some types of paleoclimatic records, and deep sea core records come from long distances away from the actual fossil and stone tool remains. The Hominin Sites and Paleolakes Drilling Project (HSPDP) was developed to address these issues. The project has focused its efforts on the eastern African Rift Valley, where much of the evidence for early hominins has been recovered. We have collected about 2 km of sediment drill core from six basins in Kenya and Ethiopia, in lake deposits immediately adjacent to important fossil hominin and archaeological sites. Collectively these cores cover in time many of the key transitions and critical intervals in human evolutionary history over the last 4 Ma, such as the earliest stone tools, the origin of our own genus Homo, and the earliest anatomically modern Homo sapiens. Here we document the initial field, physical property, and core description results of the 2012-2014 HSPDP coring campaign.},
  language  = {en}
}
@article{MehnerAttermeyerBraunsetal.2016,
  author    = {Mehner, T. and Attermeyer, Katrin and Brauns, Mario and Brothers, Soren M. and Diekmann, J. and Gaedke, Ursula and Grossart, Hans-Peter and Koehler, J. and Lischke, Betty and Meyer, N. and Scharnweber, Inga Kristin and Syvaranta, J. and Vanni, M. J. and Hilt, S.},
  title     = {Weak Response of Animal Allochthony and Production to Enhanced Supply of Terrestrial Leaf Litter in Nutrient-Rich Lakes},
  series = {Ecosystems},
  volume    = {19},
  journal   = {Ecosystems},
  publisher = {Springer},
  address   = {New York},
  issn      = {1432-9840},
  doi       = {10.1007/s10021-015-9933-2},
  pages     = {311 -- 325},
  year      = {2016},
  abstract  = {Ecosystems are generally linked via fluxes of nutrients and energy across their boundaries. For example, freshwater ecosystems in temperate regions may receive significant inputs of terrestrially derived carbon via autumnal leaf litter. This terrestrial particulate organic carbon (POC) is hypothesized to subsidize animal production in lakes, but direct evidence is still lacking. We divided two small eutrophic lakes each into two sections and added isotopically distinct maize litter to the treatment sections to simulate increased terrestrial POC inputs via leaf litter in autumn. We quantified the reliance of aquatic consumers on terrestrial resources (allochthony) in the year subsequent to POC additions by applying mixing models of stable isotopes. We also estimated lake-wide carbon (C) balances to calculate the C flow to the production of the major aquatic consumer groups: benthic macroinvertebrates, crustacean zooplankton, and fish. The sum of secondary production of crustaceans and benthic macroinvertebrates supported by terrestrial POC was higher in the treatment sections of both lakes. In contrast, total secondary and tertiary production (supported by both autochthonous and allochthonous C) was higher in the reference than in the treatment sections of both lakes. Average aquatic consumer allochthony per lake section was 27-40\%, although terrestrial POC contributed less than about 10\% to total organic C supply to the lakes. The production of aquatic consumers incorporated less than 5\% of the total organic C supply in both lakes, indicating a low ecological efficiency. We suggest that the consumption of terrestrial POC by aquatic consumers facilitates a strong coupling with the terrestrial environment. However, the high autochthonous production and the large pool of autochthonous detritus in these nutrient-rich lakes make terrestrial POC quantitatively unimportant for the C flows within food webs.},
  language  = {en}
}
@misc{HermanussenIpsenMummetal.2016,
  author    = {Hermanussen, Michael and Ipsen, Josefin and Mumm, Rebekka and Assmann, Christian and Quitmann, Julia and Gomula, Aleksandra and Lehmann, Andreas and Jasch, Isabelle and Tassenaar, Vincent and Bogin, Barry and Satake, Takashi and Scheffler, Christiane and Nunez, Javier and Godina, Elena and Hardeland, Ruediger and Boldsen, Jesper L. and El-Shabrawi, Mortada and Elhusseini, Mona and Barbu, Carmen Gabriela and Pop, Ralucca and Soederhaell, Jani and Merker, Andrea and Swanson, James and Groth, Detlef},
  title     = {Stunted Growth. Proceedings of the 23rd Aschauer Soiree, Held at Aschauhof, Germany, November 7th 2015},
  series = {Pediatric Endocrinology Reviews},
  volume    = {13},
  journal   = {Pediatric Endocrinology Reviews},
  publisher = {Medical Media},
  address   = {Netanya},
  issn      = {1565-4753},
  pages     = {756 -- 767},
  year      = {2016},
  abstract  = {Twenty-four scientists met at Aschauhof, Altenhof, Germany, to discuss the associations between child growth and development, and nutrition, health, environment and psychology. Meta-analyses of body height, height variability and household inequality, in historic and modern growth studies published since 1794, highlighting the enormously flexible patterns of child and adolescent height and weight increments throughout history which do not only depend on genetics, prenatal development, nutrition, health, and economic circumstances, but reflect social interactions. A Quality of Life in Short Stature Youth Questionnaire was presented to cross-culturally assess health-related quality of life in children. Changes of child body proportions in recent history, the relation between height and longevity in historic Dutch samples and also measures of body height in skeletal remains belonged to the topics of this meeting. Bayesian approaches and Monte Carlo simulations offer new statistical tools for the study of human growth.},
  language  = {en}
}
@article{Salzer2016,
  author    = {Salzer, Dorothea M.},
  title     = {Adam, Eve, and Jewish Children: Rewriting the Creation of Eve for the Jewish Young at the Beginning of Jewish Modernization},
  series = {The Jewish quarterly review},
  volume    = {106},
  journal   = {The Jewish quarterly review},
  publisher = {University of Pennsylvania Press},
  address   = {Philadelphia},
  issn      = {0021-6682},
  doi       = {10.1353/jqr.2016.0029},
  pages     = {396 -- 411},
  year      = {2016},
  abstract  = {At the end of the 18th century, the Jewish enlighteners invented the Genre of Jewish German Children's Bibles in their aim to reform the Jewish education system in German speaking areas. This paper initially provides a short introduction to some of the main features of the genre. Subsequently, the story of Eve's creation as it appears in two of its earliest representatives, Peter Beer's Sefer toledot yisra'el (1796) and Immanuel Moritz Neumann's Sefer torat ha-elohim (1816), is analyzed and compared, exploring the literary and interpretative strategies of the two authors in their respective contemporary contexts. Finally, the paper illustrates some of the contributions of Jewish Children's Bibles to our understanding of the Haskala and the early stages of Jewish modernization.},
  language  = {en}
}
@article{KronbergRashevDalyetal.2016,
  author    = {Kronberg, Elena A. and Rashev, M. V. and Daly, P. W. and Shprits, Yuri and Turner, D. L. and Drozdov, Alexander and Dobynde, M. and Kellerman, Adam C. and Fritz, T. A. and Pierrard, V. and Borremans, K. and Klecker, B. and Friedel, R.},
  title     = {Contamination in electron observations of the silicon detector on board},
  series = {Space Weather: The International Journal of Research and Applications},
  volume    = {14},
  journal   = {Space Weather: The International Journal of Research and Applications},
  publisher = {American Geophysical Union},
  address   = {Washington},
  issn      = {1542-7390},
  doi       = {10.1002/2016SW001369},
  pages     = {449 -- 462},
  year      = {2016},
  abstract  = {Since more than 15 years, the Cluster mission passes through Earth's radiation belts at least once every 2 days for several hours, measuring the electron intensity at energies from 30 to 400 keV. These data have previously been considered not usable due to contamination caused by penetrating energetic particles (protons at >100 keV and electrons at >400 keV). In this study, we assess the level of distortion of energetic electron spectra from the Research with Adaptive Particle Imaging Detector (RAPID)/Imaging Electron Spectrometer (IES) detector, determining the efficiency of its shielding. We base our assessment on the analysis of experimental data and a radiation transport code (Geant4). In simulations, we use the incident particle energy distribution of the AE9/AP9 radiation belt models. We identify the Roederer L values, L\&\#8902;, and energy channels that should be used with caution: at 3\&\#8804;L\&\#8902;\&\#8804;4, all energy channels (40-400 keV) are contaminated by protons (\&\#8771;230 to 630 keV and >600 MeV); at L\&\#8902;\&\#8771;1 and 4-6, the energy channels at 95-400 keV are contaminated by high-energy electrons (>400 keV). Comparison of the data with electron and proton observations from RBSP/MagEIS indicates that the subtraction of proton fluxes at energies \&\#8771; 230-630 keV from the IES electron data adequately removes the proton contamination. We demonstrate the usefulness of the corrected data for scientific applications.},
  language  = {en}
}
@article{BomansonJanhunenSchaubetal.2016,
  author    = {Bomanson, Jori and Janhunen, Tomi and Schaub, Torsten and Gebser, Martin and Kaufmann, Benjamin},
  title     = {Answer Set Programming Modulo Acyclicity},
  series = {Fundamenta informaticae},
  volume    = {147},
  journal   = {Fundamenta informaticae},
  publisher = {IOS Press},
  address   = {Amsterdam},
  issn      = {0169-2968},
  doi       = {10.3233/FI-2016-1398},
  pages     = {63 -- 91},
  year      = {2016},
  abstract  = {Acyclicity constraints are prevalent in knowledge representation and applications where acyclic data structures such as DAGs and trees play a role. Recently, such constraints have been considered in the satisfiability modulo theories (SMT) framework, and in this paper we carry out an analogous extension to the answer set programming (ASP) paradigm. The resulting formalism, ASP modulo acyclicity, offers a rich set of primitives to express constraints related to recursive structures. In the technical results of the paper, we relate the new generalization with standard ASP by showing (i) how acyclicity extensions translate into normal rules, (ii) how weight constraint programs can be instrumented by acyclicity extensions to capture stability in analogy to unfounded set checking, and (iii) how the gap between supported and stable models is effectively closed in the presence of such an extension. Moreover, we present an efficient implementation of acyclicity constraints by incorporating a respective propagator into the state-of-the-art ASP solver CLASP. The implementation provides a unique combination of traditional unfounded set checking with acyclicity propagation. In the experimental part, we evaluate the interplay of these orthogonal checks by equipping logic programs with supplementary acyclicity constraints. The performance results show that native support for acyclicity constraints is a worthwhile addition, furnishing a complementary modeling construct in ASP itself as well as effective means for translation-based ASP solving.},
  language  = {en}
}
@article{VorburgerNedielkovBrosigetal.2016,
  author    = {Vorburger, Thomas and Nedielkov, Ruslan and Brosig, Alexander and Bok, Eva and Schunke, Emina and Steffen, Wojtek and Mayer, Sonja and Goetz, Friedrich and M{\"o}ller, Heiko Michael and Steuber, Julia},
  title     = {Role of the Na+-translocating NADH:quinone oxidoreductase in voltage generation and Na+ extrusion in Vibrio cholerae},
  series = {Biochimica et biophysica acta : Bioenergetics},
  volume    = {1857},
  journal   = {Biochimica et biophysica acta : Bioenergetics},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0005-2728},
  doi       = {10.1016/j.bbabio.2015.12.010},
  pages     = {473 -- 482},
  year      = {2016},
  abstract  = {For Vibrio cholerae, the coordinated import and export of Na+ is crucial for adaptation to habitats with different osmolarities. We investigated the Na+-extruding branch of the sodium cycle in this human pathogen by in vivo Na-23-NMR spectroscopy. The Na+ extrusion activity of cells was monitored after adding glucose which stimulated respiration via the Na+-translocating NADH:quinone oxidoreductase (Na+-NQR). In a V. cholerae deletion mutant devoid of the Na+-NQR encoding genes (nqrA-F), rates of respiratory Na+ extrusion were decreased by a factor of four, but the cytoplasmic Na+ concentration was essentially unchanged. Furthermore, the mutant was impaired in formation of transmembrane voltage (Delta psi, inside negative) and did not grow under hypoosmotic conditions at pH 8.2 or above. This growth defect could be complemented by transformation with the plasmid encoded nqr operon. In an alkaline environment, Na+/H+ antiporters acidify the cytoplasm at the expense of the transmembrane voltage. It is proposed that, at alkaline pH and limiting Na+ concentrations, the Na+-NQR is crucial for generation of a transmembrane voltage to drive the import of H+ by electrogenic Na+/H+ antiporters. Our study provides the basis to understand the role of the Na+-NQR in pathogenicity of V. cholerae and other pathogens relying on this primary Na+ pump for respiration. (C) 2015 Elsevier B.V. All rights reserved.},
  language  = {en}
}
@article{Kohler2016,
  author    = {Kohler, Ulrich},
  title     = {Anforderungen an Hochschulabsolventen},
  series = {Human Resources : Qualit{\"a}tsaspekte der Ausbildung in der empirischen Forschung},
  journal   = {Human Resources : Qualit{\"a}tsaspekte der Ausbildung in der empirischen Forschung},
  editor    = {K{\"o}nig, Christian and Stahl, Matthias Matthias Stahl and Wiegand, Erich},
  publisher = {Springer},
  address   = {Wiesbaden},
  isbn      = {978-3-658-12567-7},
  doi       = {10.1007/978-3-658-12568-4_4},
  pages     = {43 -- 77},
  year      = {2016},
  abstract  = {Was sollten Mitarbeiter in einem empirisch ausgerichteten Forschungsprojekt k{\"o}nnen, und welche Kernkompetenzen sollte die Ausbildung an den Universit{\"a}ten daher vermitteln? Die Antworten auf diese Fragen h{\"a}ngen - wie sollte es anders sein - von der inhaltlichen Fragestellung und methodischen Ausrichtung des jeweiligen Forschungsprojektes ab. Nat{\"u}rlich sollten Projektmitarbeiter {\"u}ber Vorkenntnisse zum Forschungsthema verf{\"u}gen. Nat{\"u}rlich sollten Kenntnisse des projektspezifischen (statistischen) Methodenarsenals vorliegen.},
  language  = {de}
}
@article{OstrowskiPauleveSchaubetal.2016,
  author    = {Ostrowski, Max and Pauleve, L. and Schaub, Torsten and Siegel, A. and Guziolowski, Carito},
  title     = {Boolean network identification from perturbation time series data combining dynamics abstraction and logic programming},
  series = {Biosystems : journal of biological and information processing sciences},
  volume    = {149},
  journal   = {Biosystems : journal of biological and information processing sciences},
  publisher = {Elsevier},
  address   = {Oxford},
  issn      = {0303-2647},
  doi       = {10.1016/j.biosystems.2016.07.009},
  pages     = {139 -- 153},
  year      = {2016},
  abstract  = {Boolean networks (and more general logic models) are useful frameworks to study signal transduction across multiple pathways. Logic models can be learned from a prior knowledge network structure and multiplex phosphoproteomics data. However, most efficient and scalable training methods focus on the comparison of two time-points and assume that the system has reached an early steady state. In this paper, we generalize such a learning procedure to take into account the time series traces of phosphoproteomics data in order to discriminate Boolean networks according to their transient dynamics. To that end, we identify a necessary condition that must be satisfied by the dynamics of a Boolean network to be consistent with a discretized time series trace. Based on this condition, we use Answer Set Programming to compute an over-approximation of the set of Boolean networks which fit best with experimental data and provide the corresponding encodings. Combined with model-checking approaches, we end up with a global learning algorithm. Our approach is able to learn logic models with a true positive rate higher than 78\% in two case studies of mammalian signaling networks; for a larger case study, our method provides optimal answers after 7 min of computation. We quantified the gain in our method predictions precision compared to learning approaches based on static data. Finally, as an application, our method proposes erroneous time-points in the time series data with respect to the optimal learned logic models. (C) 2016 Elsevier Ireland Ltd. All rights reserved.},
  language  = {en}
}
@misc{SaritoprakVorpahlTuranetal.2016,
  author    = {Saritoprak, Zeki and Vorpahl, Daniel and Turan, Hakan and Arslan, Hakki and Zoref, Arye and Tarabieh, Abdallah and Yeshaya, Joachim and Anzi, Menashe and Merkur, Lianne and Schmidt, Daniela and Schuster, Dirk and Langer, Armin and Blum, Rahel and St{\"u}rmann, Jakob and Pohlmann, Julia and Schulz, Michael Karl and Arnold, Rafael D. and Salzer, Dorothea M. and Geißler-Gr{\"u}nberg, Anke and Talabardon, Susanne and Rasumny, Wiebke and Stellmacher, Martha and Denz, Rebekka and Walter, Simon and Gr{\"o}zinger, Elvira},
  title     = {PaRDeS : Zeitschrift der Vereinigung f{\"u}r J{\"u}dische Studien = Muslimisch-J{\"u}discher Dialog},
  series = {PaRDeS : Zeitschrift der Vereinigung f{\"u}r J{\"u}dische Studien e.V.},
  journal   = {PaRDeS : Zeitschrift der Vereinigung f{\"u}r J{\"u}dische Studien e.V.},
  number    = {22},
  editor    = {Riemer, Nathanael and Sanci, Kadir and Schulz, Michael Karl},
  publisher = {Universit{\"a}tsverlag Potsdam},
  address   = {Potsdam},
  isbn      = {978-3-86956-370-1},
  issn      = {1614-6492},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-95416},
  pages     = {280},
  year      = {2016},
  abstract  = {PaRDeS. Zeitschrift der Vereinigung f{\"u}r J{\"u}dische Studien e.V., m{\"o}chte die fruchtbare und facettenreiche Kultur des Judentums sowie seine Ber{\"u}hrungspunkte zur Umwelt in den unterschiedlichen Bereichen dokumentieren. Daneben dient die Zeitschrift als Forum zur Positionierung der F{\"a}cher J{\"u}dische Studien und Judaistik innerhalb des wissenschaftlichen Diskurses sowie zur Diskussion ihrer historischen und gesellschaftlichen Verantwortung.},
  language  = {de}
}
@misc{Salzer2016,
  author    = {Salzer, Dorothea M.},
  title     = {Naphtali Herz Wessely: Worte des Friedens und der Wahrheit. Dokumente einer Kontroverse {\"u}ber Erziehung in der europ{\"a}ischen Sp{\"a}taufkl{\"a}rung. Herausgegeben, eingeleitet und kommentiert von Ingrid Lohmann, mitherausgegeben von Rainer Wenzel / Uta Lohmann. Aus dem Hebr{\"a}ischen {\"u}bersetzt und mit Anmerkungen versehen von Rainer Wenzel / rezensiert von Dorothea Salzer},
  series = {PaRDeS : Zeitschrift der Vereinigung f{\"u}r J{\"u}dische Studien [22 (2016)] = Muslim-Jewish Dialogue},
  volume    = {22},
  journal   = {PaRDeS : Zeitschrift der Vereinigung f{\"u}r J{\"u}dische Studien [22 (2016)] = Muslim-Jewish Dialogue},
  publisher = {Universit{\"a}tsverlag Potsdam},
  address   = {Potsdam},
  isbn      = {978-3-86956-370-1},
  issn      = {1614-6492},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-99807},
  pages     = {218 -- 221},
  year      = {2016},
  abstract  = {Rezensiertes Werk: Naphtali Herz Wessely: Worte des Friedens und der Wahrheit. Dokumente einer Kontroverse {\"u}ber Erziehung in der europ{\"a}ischen Sp{\"a}taufkl{\"a}rung. Herausgegeben, eingeleitet und kommentiert von Ingrid Lohmann, mitherausgegeben von Rainer Wenzel / Uta Lohmann. Aus dem Hebr{\"a}ischen {\"u}bersetzt und mit Anmerkungen versehen von Rainer Wenzel, J{\"u}dische Bildungsgeschichte in Deutschland, Bd. 8, M{\"u}nster: Waxmann 2014. 800 S.},
  language  = {de}
}
@article{AseevShpritsDrozdovetal.2016,
  author    = {Aseev, Nikita and Shprits, Yuri and Drozdov, Alexander and Kellerman, Adam C.},
  title     = {Numerical applications of the advective-diffusive codes for the inner magnetosphere},
  series = {Space Weather: The International Journal of Research and Applications},
  volume    = {14},
  journal   = {Space Weather: The International Journal of Research and Applications},
  publisher = {American Geophysical Union},
  address   = {Washington},
  issn      = {1542-7390},
  doi       = {10.1002/2016SW001484},
  pages     = {993 -- 1010},
  year      = {2016},
  abstract  = {In this study we present analytical solutions for convection and diffusion equations. We gather here the analytical solutions for the one-dimensional convection equation, the two-dimensional convection problem, and the one- and two-dimensional diffusion equations. Using obtained analytical solutions, we test the four-dimensional Versatile Electron Radiation Belt code (the VERB-4D code), which solves the modified Fokker-Planck equation with additional convection terms. The ninth-order upwind numerical scheme for the one-dimensional convection equation shows much more accurate results than the results obtained with the third-order scheme. The universal limiter eliminates unphysical oscillations generated by high-order linear upwind schemes. Decrease in the space step leads to convergence of a numerical solution of the two-dimensional diffusion equation with mixed terms to the analytical solution. We compare the results of the third- and ninth-order schemes applied to magnetospheric convection modeling. The results show significant differences in electron fluxes near geostationary orbit when different numerical schemes are used.},
  language  = {en}
}
@article{KimShpritsBlake2016,
  author    = {Kim, Kyung-Chan and Shprits, Yuri and Blake, J. Bernard},
  title     = {Fast injection of the relativistic electrons into the inner zone and the formation of the split-zone structure during the Bastille Day storm in July 2000},
  series = {Journal of geophysical research : Space physics},
  volume    = {121},
  journal   = {Journal of geophysical research : Space physics},
  publisher = {American Geophysical Union},
  address   = {Washington},
  issn      = {2169-9380},
  doi       = {10.1002/2015JA022072},
  pages     = {8329 -- 8342},
  year      = {2016},
  abstract  = {During the July 2000 geomagnetic storm, known as the Bastille Day storm, Solar, Anomalous, and Magnetospheric Particle Explorer (SAMPEX)/Heavy Ion Large Telescope (HILT) observed a strong injection of similar to 1MeV electrons into the slot region (L similar to 2.5) during the storm main phase. Then, during the following month, electrons were clearly seen diffusing inward down to L=2 and forming a pronounced split structure encompassing a narrow, newly formed slot region around L=3. SAMPEX observations are first compared with electron and proton observations on HEO-3 and NOAA-15 to validate that the observed unusual dynamics was not caused by proton contamination of the SAMPEX instrument. The time-dependent 3-D Versatile Electron Radiation Belt (VERB) simulation of 1MeV electron flux evolution is compared with the SAMPEX/HILT observations. The results show that the VERB code predicts overall time evolution of the observed split structure. The simulated split structure is produced by pitch angle scattering into the Earth atmosphere of similar to 1MeV electrons by plasmaspheric hiss.},
  language  = {en}
}
@article{ShpritsDrozdovSpasojevicetal.2016,
  author    = {Shprits, Yuri and Drozdov, Alexander and Spasojevic, Maria and Kellerman, Adam C. and Usanova, Maria E. and Engebretson, Mark J. and Agapitov, Oleksiy V. and Zhelavskaya, Irina and Raita, Tero J. and Spence, Harlan E. and Baker, Daniel N. and Zhu, Hui and Aseev, Nikita},
  title     = {Wave-induced loss of ultra-relativistic electrons in the Van Allen radiation belts},
  series = {Nature Communications},
  volume    = {7},
  journal   = {Nature Communications},
  publisher = {Nature Publ. Group},
  address   = {London},
  issn      = {2041-1723},
  doi       = {10.1038/ncomms12883},
  pages     = {7},
  year      = {2016},
  language  = {en}
}
@article{RipollLoridanCunninghametal.2016,
  author    = {Ripoll, Jean-Fran{\c{c}}ois and Loridan, Vivien and Cunningham, G. S. and Reeves, Geoffrey D. and Shprits, Yuri},
  title     = {On the time needed to reach an equilibrium structure of the radiation belts},
  series = {Journal of geophysical research : Space physics},
  volume    = {121},
  journal   = {Journal of geophysical research : Space physics},
  publisher = {American Geophysical Union},
  address   = {Washington},
  issn      = {2169-9380},
  doi       = {10.1002/2015JA022207},
  pages     = {7684 -- 7698},
  year      = {2016},
  abstract  = {In this study, we complement the notion of equilibrium states of the radiation belts with a discussion on the dynamics and time needed to reach equilibrium. We solve for the equilibrium states obtained using 1-D radial diffusion with recently developed hiss and chorus lifetimes at constant values of Kp = 1, 3, and 6. We find that the equilibrium states at moderately low Kp, when plotted versus L shell (L) and energy (E), display the same interesting S shape for the inner edge of the outer belt as recently observed by the Van Allen Probes. The S shape is also produced as the radiation belts dynamically evolve toward the equilibrium state when initialized to simulate the buildup after a massive dropout or to simulate loss due to outward diffusion from a saturated state. Physically, this shape, intimately linked with the slot structure, is due to the dependence of electron loss rate (originating from wave-particle interactions) on both energy and L shell. Equilibrium electron flux profiles are governed by the Biot number (tau(Diffusion)/tau(loss)), with large Biot number corresponding to low fluxes and low Biot number to large fluxes. The time it takes for the flux at a specific (L, E) to reach the value associated with the equilibrium state, starting from these different initial states, is governed by the initial state of the belts, the property of the dynamics (diffusion coefficients), and the size of the domain of computation. Its structure shows a rather complex scissor form in the (L, E) plane. The equilibrium value (phase space density or flux) is practically reachable only for selected regions in (L, E) and geomagnetic activity. Convergence to equilibrium requires hundreds of days in the inner belt for E>300 keV and moderate Kp (<= 3). It takes less time to reach equilibrium during disturbed geomagnetic conditions (Kp = 3), when the system evolves faster. Restricting our interest to the slot region, below L = 4, we find that only small regions in (L, E) space can reach the equilibrium value: E similar to [200, 300] keV for L= [3.7, 4] at Kp= 1, E similar to[0.6, 1] MeV for L = [3, 4] at Kp = 3, and E similar to 300 keV for L = [3.5, 4] at Kp = 6 assuming no new incoming electrons.},
  language  = {en}
}
@article{ZhelavskayaSpasojevicShpritsetal.2016,
  author    = {Zhelavskaya, Irina and Spasojevic, M. and Shprits, Yuri and Kurth, William S.},
  title     = {Automated determination of electron density from electric field measurements on the Van Allen Probes spacecraft},
  series = {Journal of geophysical research : Space physics},
  volume    = {121},
  journal   = {Journal of geophysical research : Space physics},
  publisher = {American Geophysical Union},
  address   = {Washington},
  issn      = {2169-9380},
  doi       = {10.1002/2015JA022132},
  pages     = {4611 -- 4625},
  year      = {2016},
  abstract  = {We present the Neural-network-based Upper hybrid Resonance Determination (NURD) algorithm for automatic inference of the electron number density from plasma wave measurements made on board NASA's Van Allen Probes mission. A feedforward neural network is developed to determine the upper hybrid resonance frequency, fuhr, from electric field measurements, which is then used to calculate the electron number density. In previous missions, the plasma resonance bands were manually identified, and there have been few attempts to do robust, routine automated detections. We describe the design and implementation of the algorithm and perform an initial analysis of the resulting electron number density distribution obtained by applying NURD to 2.5 years of data collected with the Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) instrumentation suite of the Van Allen Probes mission. Densities obtained by NURD are compared to those obtained by another recently developed automated technique and also to an existing empirical plasmasphere and trough density model.},
  language  = {en}
}
@article{BoydSpenceHuangetal.2016,
  author    = {Boyd, A. J. and Spence, Harlan E. and Huang, Chia-Lin and Reeves, Geoffrey D. and Baker, Daniel N. and Turner, D. L. and Claudepierre, Seth G. and Fennell, Joseph F. and Blake, J. Bernard and Shprits, Yuri},
  title     = {Statistical properties of the radiation belt seed population},
  series = {Journal of geophysical research : Space physics},
  volume    = {121},
  journal   = {Journal of geophysical research : Space physics},
  publisher = {American Geophysical Union},
  address   = {Washington},
  issn      = {2169-9380},
  doi       = {10.1002/2016JA022652},
  pages     = {7636 -- 7646},
  year      = {2016},
  abstract  = {We present a statistical analysis of phase space density data from the first 26 months of the Van Allen Probes mission. In particular, we investigate the relationship between the tens and hundreds of keV seed electrons and >1 MeV core radiation belt electron population. Using a cross-correlation analysis, we find that the seed and core populations are well correlated with a coefficient of approximate to 0.73 with a time lag of 10-15 h. We present evidence of a seed population threshold that is necessary for subsequent acceleration. The depth of penetration of the seed population determines the inner boundary of the acceleration process. However, we show that an enhanced seed population alone is not enough to produce acceleration in the higher energies, implying that the seed population of hundreds of keV electrons is only one of several conditions required for MeV electron radiation belt acceleration.},
  language  = {en}
}
@article{AbseherMusliuWoltranetal.2016,
  author    = {Abseher, Michael and Musliu, Nysret and Woltran, Stefan and Gebser, Martin and Schaub, Torsten},
  title     = {Shift Design with Answer Set Programming},
  series = {Fundamenta informaticae},
  volume    = {147},
  journal   = {Fundamenta informaticae},
  publisher = {IOS Press},
  address   = {Amsterdam},
  issn      = {0169-2968},
  doi       = {10.3233/FI-2016-1396},
  pages     = {1 -- 25},
  year      = {2016},
  abstract  = {Answer Set Programming (ASP) is a powerful declarative programming paradigm that has been successfully applied to many different domains. Recently, ASP has also proved successful for hard optimization problems like course timetabling and travel allotment. In this paper, we approach another important task, namely, the shift design problem, aiming at an alignment of a minimum number of shifts in order to meet required numbers of employees (which typically vary for different time periods) in such a way that over- and understaffing is minimized. We provide an ASP encoding of the shift design problem, which, to the best of our knowledge, has not been addressed by ASP yet. Our experimental results demonstrate that ASP is capable of improving the best known solutions to some benchmark problems. Other instances remain challenging and make the shift design problem an interesting benchmark for ASP-based optimization methods.},
  language  = {en}
}
@article{GebserSchaub2016,
  author    = {Gebser, Martin and Schaub, Torsten},
  title     = {Modeling and Language Extensions},
  series = {AI magazine},
  volume    = {37},
  journal   = {AI magazine},
  publisher = {Association for the Advancement of Artificial Intelligence},
  address   = {Menlo Park},
  issn      = {0738-4602},
  pages     = {33 -- 44},
  year      = {2016},
  abstract  = {Answer set programming (ASP) has emerged as an approach to declarative problem solving based on the stable model semantics for logic programs. The basic idea is to represent a computational problem by a logic program, formulating constraints in terms of rules, such that its answer sets correspond to problem solutions. To this end, ASP combines an expressive language for high-level modeling with powerful low-level reasoning capacities, provided by off-the-shelf tools. Compact problem representations take advantage of genuine modeling features of ASP, including (first-order) variables, negation by default, and recursion. In this article, we demonstrate the ASP methodology on two example scenarios, illustrating basic as well as advanced modeling and solving concepts. We also discuss mechanisms to represent and implement extended kinds of preferences and optimization. An overview of further available extensions concludes the article.},
  language  = {en}
}
@article{KaufmannLeonePerrietal.2016,
  author    = {Kaufmann, Benjamin and Leone, Nicola and Perri, Simona and Schaub, Torsten},
  title     = {Grounding and Solving in Answer Set Programming},
  series = {AI magazine},
  volume    = {37},
  journal   = {AI magazine},
  publisher = {Association for the Advancement of Artificial Intelligence},
  address   = {Menlo Park},
  issn      = {0738-4602},
  pages     = {25 -- 32},
  year      = {2016},
  abstract  = {Answer set programming is a declarative problem-solving paradigm that rests upon a work flow involving modeling, grounding, and solving. While the former is described by Gebser and Schaub (2016), we focus here on key issues in grounding, or how to systematically replace object variables by ground terms in an effective way, and solving, or how to compute the answer sets, of a propositional logic program obtained by grounding.},
  language  = {en}
}
@article{BozzoOskinovaFeldmeieretal.2016,
  author    = {Bozzo, Enrico and Oskinova, Lidia M. and Feldmeier, Achim and Falanga, M.},
  title     = {Clumpy wind accretion in supergiant neutron star high mass X-ray binaries},
  series = {BMC neuroscience},
  volume    = {589},
  journal   = {BMC neuroscience},
  publisher = {EDP Sciences},
  address   = {Les Ulis},
  issn      = {1432-0746},
  doi       = {10.1051/0004-6361/201628341},
  pages     = {369 -- 389},
  year      = {2016},
  abstract  = {The accretion of the stellar wind material by a compact object represents the main mechanism powering the X-ray emission in classical supergiant high mass X-ray binaries and supergiant fast X-ray transients. In this work we present the first attempt to simulate the accretion process of a fast and dense massive star wind onto a neutron star, taking into account the effects of the centrifugal and magnetic inhibition of accretion ("gating") due to the spin and magnetic field of the compact object. We made use of a radiative hydrodynamical code to model the nonstationary radiatively driven wind of an O-B supergiant star and then place a neutron star characterized by a fixed magnetic field and spin period at a certain distance from the massive companion. Our calculations follow, as a function of time (on a total timescale of several hours), the transitions of the system through all different accretion regimes that are triggered by the intrinsic variations in the density and velocity of the nonstationary wind. The X-ray luminosity released by the system is computed at each time step by taking into account the relevant physical processes occurring in the different accretion regimes. Synthetic lightcurves are derived and qualitatively compared with those observed from classical supergiant high mass X-ray binaries and supergiant fast X-ray transients. Although a number of simplifications are assumed in these calculations, we show that taking into account the effects of the centrifugal and magnetic inhibition of accretion significantly reduces the average X-ray luminosity expected for any neutron star wind-fed binary. The present model calculations suggest that long spin periods and stronger magnetic fields are favored in order to reproduce the peculiar behavior of supergiant fast X-ray transients in the X-ray domain.},
  language  = {en}
}
@article{ShenarHainichTodtetal.2016,
  author    = {Shenar, Tomer and Hainich, Rainer and Todt, Helge Tobias and Sander, Andreas Alexander Christoph and Hamann, Wolf-Rainer and Moffat, Anthony F. J. and Eldridge, J. J. and Pablo, H. and Oskinova, Lidia M. and Richardson, N. D.},
  title     = {Wolf-Rayet stars in the Small Magellanic Cloud II. Analysis of the binaries},
  series = {American mineralogist : an international journal of earth and planetary materials},
  volume    = {591},
  journal   = {American mineralogist : an international journal of earth and planetary materials},
  publisher = {EDP Sciences},
  address   = {Les Ulis},
  issn      = {1432-0746},
  doi       = {10.1051/0004-6361/201527916},
  pages     = {25},
  year      = {2016},
  abstract  = {Context. Massive Wolf-Rayet (WR) stars are evolved massive stars (M-i greater than or similar to 20 M-circle dot) characterized by strong mass-loss. Hypothetically, they can form either as single stars or as mass donors in close binaries. About 40\% of all known WR stars are confirmed binaries, raising the question as to the impact of binarity on the WR population. Studying WR binaries is crucial in this context, and furthermore enable one to reliably derive the elusive masses of their components, making them indispensable for the study of massive stars. Aims. By performing a spectral analysis of all multiple WR systems in the Small Magellanic Cloud (SMC), we obtain the full set of stellar parameters for each individual component. Mass-luminosity relations are tested, and the importance of the binary evolution channel is assessed. Methods. The spectral analysis is performed with the PotsdamWolf-Rayet (PoWR) model atmosphere code by superimposing model spectra that correspond to each component. Evolutionary channels are constrained using the Binary Population and Spectral Synthesis (BPASS) evolution tool. Results. Significant hydrogen mass fractions (0.1 < X-H < 0.4) are detected in all WN components. A comparison with mass-luminosity relations and evolutionary tracks implies that the majority of the WR stars in our sample are not chemically homogeneous. The WR component in the binary AB6 is found to be very luminous (log L approximate to 6.3 [L-circle dot]) given its orbital mass (approximate to 10 M-circle dot), presumably because of observational contamination by a third component. Evolutionary paths derived for our objects suggest that Roche lobe overflow had occurred in most systems, affecting their evolution. However, the implied initial masses (greater than or similar to 60 M-circle dot) are large enough for the primaries to have entered the WR phase, regardless of binary interaction. Conclusions. Together with the results for the putatively single SMC WR stars, our study suggests that the binary evolution channel does not dominate the formation of WR stars at SMC metallicity.},
  language  = {en}
}
@article{ZwickelKahlKlaffkeetal.2016,
  author    = {Zwickel, Theresa and Kahl, Sandra and Klaffke, Horst and Rychlik, Michael and M{\"u}ller, Marina E. H.},
  title     = {Spotlight on the Underdogs-An Analysis of Underrepresented Alternaria Mycotoxins Formed Depending on Varying Substrate, Time and Temperature Conditions},
  series = {Toxins},
  volume    = {8},
  journal   = {Toxins},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {2072-6651},
  doi       = {10.3390/toxins8110344},
  pages     = {570 -- 583},
  year      = {2016},
  abstract  = {Alternaria (A.) is a genus of widespread fungi capable of producing numerous, possibly health-endangering Alternaria toxins (ATs), which are usually not the focus of attention. The formation of ATs depends on the species and complex interactions of various environmental factors and is not fully understood. In this study the influence of temperature (7 degrees C, 25 degrees C), substrate (rice, wheat kernels) and incubation time (4, 7, and 14 days) on the production of thirteen ATs and three sulfoconjugated ATs by three different Alternaria isolates from the species groups A. tenuissima and A. infectoria was determined. High-performance liquid chromatography coupled with tandem mass spectrometry was used for quantification. Under nearly all conditions, tenuazonic acid was the most extensively produced toxin. At 25 degrees C and with increasing incubation time all toxins were formed in high amounts by the two A. tenuissima strains on both substrates with comparable mycotoxin profiles. However, for some of the toxins, stagnation or a decrease in production was observed from day 7 to 14. As opposed to the A. tenuissima strains, the A. infectoria strain only produced low amounts of ATs, but high concentrations of stemphyltoxin III. The results provide an essential insight into the quantitative in vitro AT formation under different environmental conditions, potentially transferable to different field and storage conditions.},
  language  = {en}
}
@misc{NauschBachCzernyetal.2016,
  author    = {Nausch, Monika and Bach, Lennart Thomas and Czerny, Jan and Goldstein, Josephine and Grossart, Hans-Peter and Hellemann, Dana and Hornick, Thomas and Achterberg, Eric Pieter and Schulz, Kai Georg and Riebesell, Ulf},
  title     = {Effects of CO 2 perturbation on phosphorus pool sizes and uptake in a mesocosm experiment during a low productive summer season in the northern Baltic Sea},
  series = {Biogeosciences},
  journal   = {Biogeosciences},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-410274},
  pages     = {16},
  year      = {2016},
  abstract  = {Studies investigating the effect of increasing CO2 levels on the phosphorus cycle in natural waters are lacking although phosphorus often controls phytoplankton development in many aquatic systems. The aim of our study was to analyse effects of elevated CO2 levels on phosphorus pool sizes and uptake. The phosphorus dynamic was followed in a CO2-manipulation mesocosm experiment in the Storfjarden (western Gulf of Finland, Baltic Sea) in summer 2012 and was also studied in the surrounding fjord water. In all mesocosms as well as in surface waters of Storfjarden, dissolved organic phosphorus (DOP) concentrations of 0.26aEuro-+/- aEuro-0.03 and 0.23aEuro-+/- aEuro-0.04aEuro-A mu molaEuro-L-1, respectively, formed the main fraction of the total P-pool (TP), whereas phosphate (PO4) constituted the lowest fraction with mean concentration of 0.15aEuro-A +/- aEuro-0.02 in the mesocosms and 0.17aEuro-A +/- aEuro-0.07aEuro-A mu molaEuro-L-1 in the fjord. Transformation of PO4 into DOP appeared to be the main pathway of PO4 turnover. About 82aEuro-\% of PO4 was converted into DOP whereby only 18aEuro-\% of PO4 was transformed into particulate phosphorus (PP). PO4 uptake rates measured in the mesocosms ranged between 0.6 and 3.9aEuro-nmolaEuro-L(-1)aEuro-h(-1). About 86aEuro-\% of them was realized by the size fraction < aEuro-3aEuro-A mu m. Adenosine triphosphate (ATP) uptake revealed that additional P was supplied from organic compounds accounting for 25-27aEuro-\% of P provided by PO4 only. CO2 additions did not cause significant changes in phosphorus (P) pool sizes, DOP composition, and uptake of PO4 and ATP when the whole study period was taken into account. However, significant short-term effects were observed for PO4 and PP pool sizes in CO2 treatments > aEuro-1000aEuro-A mu atm during periods when phytoplankton biomass increased. In addition, we found significant relationships (e.g., between PP and Chl a) in the untreated mesocosms which were not observed under high fCO(2) conditions. Consequently, it can be hypothesized that the relationship between PP formation and phytoplankton growth changed with CO2 elevation. It can be deduced from the results, that visible effects of CO2 on P pools are coupled to phytoplankton growth when the transformation of PO4 into POP was stimulated. The transformation of PO4 into DOP on the other hand does not seem to be affected. Additionally, there were some indications that cellular mechanisms of P regulation might be modified under CO2 elevation changing the relationship between cellular constituents.},
  language  = {en}
}
@misc{SpillingSchulzPauletal.2016,
  author    = {Spilling, Kristian and Schulz, Kai Georg and Paul, Allanah J. and Boxhammer, Tim and Achterberg, Eric Pieter and Hornick, Thomas and Lischka, Silke and Stuhr, Annegret and Berm{\´u}dez, Rafael and Czerny, Jan and Crawfurd, Kate and Brussaard, Corina P. D. and Grossart, Hans-Peter and Riebesell, Ulf},
  title     = {Effects of ocean acidification on pelagic carbon fluxes in a mesocosm experiment},
  series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  number    = {544},
  issn      = {1866-8372},
  doi       = {10.25932/publishup-41183},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-411835},
  pages     = {13},
  year      = {2016},
  abstract  = {About a quarter of anthropogenic CO2 emissions are currently taken up by the oceans, decreasing seawater pH. We performed a mesocosm experiment in the Baltic Sea in order to investigate the consequences of increasing CO2 levels on pelagic carbon fluxes. A gradient of different CO2 scenarios, ranging from ambient (similar to 370 mu atm) to high (similar to 1200 mu atm), were set up in mesocosm bags (similar to 55m(3)). We determined standing stocks and temporal changes of total particulate carbon (TPC), dissolved organic carbon (DOC), dissolved inorganic carbon (DIC), and particulate organic carbon (POC) of specific plankton groups. We also measured carbon flux via CO2 exchange with the atmosphere and sedimentation (export), and biological rate measurements of primary production, bacterial production, and total respiration. The experiment lasted for 44 days and was divided into three different phases (I: t0-t16; II: t17-t30; III: t31-t43). Pools of TPC, DOC, and DIC were approximately 420, 7200, and 25 200 mmol Cm-2 at the start of the experiment, and the initial CO2 additions increased the DIC pool by similar to 7\% in the highest CO2 treatment. Overall, there was a decrease in TPC and increase of DOC over the course of the experiment. The decrease in TPC was lower, and increase in DOC higher, in treatments with added CO2. During phase I the estimated gross primary production (GPP) was similar to 100 mmol C m(-2) day(-1), from which 75-95\% was respired, similar to 1\% ended up in the TPC (including export), and 5-25\% was added to the DOC pool. During phase II, the respiration loss increased to similar to 100\% of GPP at the ambient CO2 concentration, whereas respiration was lower (85-95\% of GPP) in the highest CO2 treatment. Bacterial production was similar to 30\% lower, on average, at the highest CO2 concentration than in the controls during phases II and III. This resulted in a higher accumulation of DOC and lower reduction in the TPC pool in the elevated CO2 treatments at the end of phase II extending throughout phase III. The "extra" organic carbon at high CO2 remained fixed in an increasing biomass of small-sized plankton and in the DOC pool, and did not transfer into large, sinking aggregates. Our results revealed a clear effect of increasing CO2 on the carbon budget and mineralization, in particular under nutrient limited conditions. Lower carbon loss processes (respiration and bacterial remineralization) at elevated CO2 levels resulted in higher TPC and DOC pools than ambient CO2 concentration. These results highlight the importance of addressing not only net changes in carbon standing stocks but also carbon fluxes and budgets to better disentangle the effects of ocean acidification.},
  language  = {en}
}
@article{BozzoBhaleraoPradhanetal.2016,
  author    = {Bozzo, Enrico and Bhalerao, V. and Pradhan, Prajal and Tomsick, J. and Romano, Patrizia and Ferrigno, Carlo and Chaty, S. and Oskinova, Lidia M. and Manousakis, A. and Walter, R. and Falanga, M. and Campana, S. and Stella, L. and Ramolla, M. and Chini, R.},
  title     = {Multi-wavelength observations of IGR J17544-2619 from quiescence to outburst},
  series = {Journal of geophysical research : Earth surface},
  volume    = {596},
  journal   = {Journal of geophysical research : Earth surface},
  publisher = {EDP Sciences},
  address   = {Les Ulis},
  issn      = {1432-0746},
  doi       = {10.1051/0004-6361/201629311},
  pages     = {12},
  year      = {2016},
  abstract  = {In this paper we report on a long multi-wavelength observational campaign of the supergiant fast X-ray transient prototype IGR J17544-2619. A 150 ks-long observation was carried out simultaneously with XMM-Newton and NuSTAR, catching the source in an initial faint X-ray state and then undergoing a bright X-ray outburst lasting approximately 7 ks. We studied the spectral variability during outburst and quiescence by using a thermal and bulk Comptonization model that is typically adopted to describe the X-ray spectral energy distribution of young pulsars in high mass X-ray binaries. Although the statistics of the collected X-ray data were relatively high, we could neither confirm the presence of a cyclotron line in the broad-band spectrum of the source (0.5-40 keV), nor detect any of the previously reported tentative detections of the source spin period. The monitoring carried out with Swift/XRT during the same orbit of the system observed by XMM-Newton and NuSTAR revealed that the source remained in a low emission state for most of the time, in agreement with the known property of all supergiant fast X-ray transients being significantly sub-luminous compared to other supergiant X-ray binaries. Optical and infrared observations were carried out for a total of a few thousand seconds during the quiescence state of the source detected by XMM-Newton and NuSTAR. The measured optical and infrared magnitudes were slightly lower than previous values reported in the literature, but compatible with the known micro-variability of supergiant stars. UV observations obtained with the UVOT telescope on-board Swift did not reveal significant changes in the magnitude of the source in this energy domain compared to previously reported values.},
  language  = {en}
}
@article{HamaguchiOskinovaRusselletal.2016,
  author    = {Hamaguchi, K. and Oskinova, Lidia M. and Russell, C. M. P. and Petre, R. and Enoto, T. and Morihana, K. and Ishida, M.},
  title     = {DISCOVERY OF RAPIDLY MOVING PARTIAL X-RAY ABSORBERS WITHIN GAMMA CASSIOPEIAE},
  series = {The astrophysical journal : an international review of spectroscopy and astronomical physics},
  volume    = {832},
  journal   = {The astrophysical journal : an international review of spectroscopy and astronomical physics},
  publisher = {IOP Publ. Ltd.},
  address   = {Bristol},
  issn      = {0004-637X},
  doi       = {10.3847/0004-637X/832/2/140},
  pages     = {33 -- 49},
  year      = {2016},
  abstract  = {detected six rapid X-ray spectral hardening events called "softness dips" in a similar to 100 ks observation in 2011. All the softness dip events show symmetric softness-ratio variations, and some of them have flat bottoms apparently due to saturation. The softness dip spectra are best described by either similar to 40\% or similar to 70\% partial covering absorption to kT similar to 12 keV plasma emission by matter with a neutral hydrogen column density of similar to(2-8) x 10(21) cm(-2), while the spectrum outside these dips is almost free of absorption. This result suggests the presence of two distinct X-ray-emitting spots in the.. Cas system, perhaps on a white dwarf (WD) companion with dipole mass accretion. The partial covering absorbers may be blobs in the Be stellar wind, the Be disk, or rotating around the WD companion. Weak correlations of the softness ratios to the hard X-ray flux suggest the presence of stable plasmas at kT similar to 0.9 and 5 keV, which may originate from the Be or WD winds. The formation of a Be star and WD binary system requires mass transfer between two stars; gamma Cas may have experienced such activity in the past.},
  language  = {en}
}
@article{OskinovaKubatovaHamann2016,
  author    = {Oskinova, Lidia M. and Kubatova, Brankica and Hamann, Wolf-Rainer},
  title     = {Moving inhomogeneous envelopes of stars},
  series = {Transport in Porous Media},
  volume    = {183},
  journal   = {Transport in Porous Media},
  publisher = {Elsevier},
  address   = {Oxford},
  issn      = {0022-4073},
  doi       = {10.1016/j.jqsrt.2016.06.017},
  pages     = {100 -- 112},
  year      = {2016},
  abstract  = {Massive stars are extremely luminous and drive strong winds, blowing a large part of their matter into the galactic environment before they finally explode as a supernova. Quantitative knowledge of massive star feedback is required to understand our Universe as we see it. Traditionally, massive stars have been studied under the assumption that their winds are homogeneous and stationary, largely relying on the Sobolev approximation. However, Observations with the newest instruments, together with progress in model calculations, ultimately dictate a cardinal change of this paradigm: stellar winds are highly inhomogeneous. Hence, we are now advancing to a new stage in our understanding of stellar winds. Using the foundations laid by V.V. Sobolev and his school, we now update and further develop the stellar spectral analysis techniques. New sophisticated 3-D models of radiation transfer in inhomogeneous expanding media elucidate the physics of stellar winds and improve classical empiric mass-loss rate diagnostics. Applications of these new techniques to multiwavelength observations of massive stars yield consistent and robust stellar wind parameters. (C) 2016 Elsevier Ltd. All rights reserved.},
  language  = {en}
}
@article{HubrigScholzHamannetal.2016,
  author    = {Hubrig, Swetlana and Scholz, Kathleen and Hamann, Wolf-Rainer and Schoeller, M. and Ignace, R. and Ilyin, Ilya and Gayley, K. G. and Oskinova, Lidia M.},
  title     = {Searching for a magnetic field in Wolf-Rayet stars using FORS 2 spectropolarimetry},
  series = {Monthly notices of the Royal Astronomical Society},
  volume    = {458},
  journal   = {Monthly notices of the Royal Astronomical Society},
  publisher = {Oxford Univ. Press},
  address   = {Oxford},
  issn      = {0035-8711},
  doi       = {10.1093/mnras/stw558},
  pages     = {3381 -- 3393},
  year      = {2016},
  abstract  = {To investigate if magnetic fields are present in Wolf-Rayet stars, we selected a few stars in the Galaxy and one in the Large Magellanic Cloud (LMC). We acquired low-resolution spectropolarimetric observations with the European Southern Observatory FORS 2 (FOcal Reducer low dispersion Spectrograph) instrument during two different observing runs. During the first run in visitor mode, we observed the LMC Wolf-Rayet star BAT99 7 and the stars WR 6, WR 7, WR 18, and WR 23 in our Galaxy. The second run in service mode was focused on monitoring the star WR 6. Linear polarization was recorded immediately after the observations of circular polarization. During our visitor observing run, the magnetic field for the cyclically variable star WR 6 was measured at a significance level of 3.3 sigma (< B-z > = 258 +/- 78 G). Among the other targets, the highest value for the longitudinal magnetic field, < B-z > = 327 +/- 141 G, was measured in the LMC star BAT99 7. Spectropolarimetric monitoring of the star WR 6 revealed a sinusoidal nature of the < B-z > variations with the known rotation period of 3.77 d, significantly adding to the confidence in the detection. The presence of the rotation-modulated magnetic variability is also indicated in our frequency periodogram. The reported field magnitude suffers from significant systematic uncertainties at the factor of 2 level, in addition to the quoted statistical uncertainties, owing to the theoretical approach used to characterize it. Linear polarization measurements showed no line effect in the stars, apart from WR 6. BAT99 7, WR 7, and WR 23 do not show variability of the linear polarization over two nights.},
  language  = {en}
}
@article{Oskinova2016,
  author    = {Oskinova, Lidia M.},
  title     = {X-ray diagnostics of massive star winds},
  series = {Advances in space research},
  volume    = {58},
  journal   = {Advances in space research},
  publisher = {Elsevier},
  address   = {Oxford},
  issn      = {0273-1177},
  doi       = {10.1016/j.asr.2016.06.030},
  pages     = {739 -- 760},
  year      = {2016},
  abstract  = {Nearly all types of massive stars with radiatively driven stellar winds are X-ray sources that can be observed by the presently operating powerful X-ray telescopes. In this review I briefly address recent advances in our understanding of stellar winds obtained from X-ray observations. X-rays may strongly influence the dynamics of weak winds of main sequence B-type stars. X-ray pulsations were detected in a beta Cep type variable giving evidence of tight photosphere-wind connections. The winds of OB dwarfs with subtypes later than O9V may be predominantly in a hot phase, and X-ray observations offer the best window for their studies. The X-ray properties of OB super giants are largely determined by the effects of radiative transfer in their clumped stellar winds. The recently suggested method to directly measure mass-loss rates of O stars by fitting the shapes of X-ray emission lines is considered but its validity cannot be confirmed. To obtain robust quantitative information on stellar wind parameters from X-ray spectroscopy, a multiwavelength analysis by means of stellar atmosphere models is required. Independent groups are now performing such analyses with encouraging results. Joint analyses of optical, UV, and X-ray spectra of OB supergiants yield consistent mass-loss rates. Depending on the adopted clumping parameters, the empirically derived mass-loss rates are a factor of a few smaller or comparable to those predicted by standard recipes (Vink et al., 2001). All sufficiently studied O stars display variable X-ray emission that might be related to corotating interaction regions in their winds. In the latest stages of stellar evolution, single red supergiants (RSG) and luminous blue variable (LBV) stars do not emit observable amounts of X-rays. On the other hand, nearly all types of Wolf-Rayet (WR) stars are X-ray sources. X-ray spectroscopy allows a sensitive probe of WR wind abundances and opacities. (C) 2016 COSPAR. Published by Elsevier Ltd. All rights reserved.},
  language  = {en}
}
@article{HubrigKholtyginIlyinetal.2016,
  author    = {Hubrig, Swetlana and Kholtygin, A. and Ilyin, Ilya and Sch{\"o}ller, M. and Oskinova, Lidia M.},
  title     = {THE FIRST SPECTROPOLARIMETRIC MONITORING OF THE PECULIAR O4 Ief SUPERGIANT zeta PUPPIS},
  series = {The astrophysical journal : an international review of spectroscopy and astronomical physics},
  volume    = {822},
  journal   = {The astrophysical journal : an international review of spectroscopy and astronomical physics},
  publisher = {IOP Publ. Ltd.},
  address   = {Bristol},
  issn      = {0004-637X},
  doi       = {10.3847/0004-637X/822/2/104},
  pages     = {7},
  year      = {2016},
  abstract  = {The origin of the magnetic field in massive O-type stars is still under debate. To model the physical processes responsible for the generation of O star magnetic fields, it is important to understand whether correlations between the presence of a magnetic field and stellar evolutionary state, rotation velocity, kinematical status, and surface composition can be identified. The O4 Ief supergiant zeta Pup is a fast rotator and a runaway star, which may be a product of a past binary interaction, possibly having had an encounter with the cluster Trumper 10 some 2 Myr ago. The currently available observational material suggests that certain observed phenomena in this star may be related to the presence of a magnetic field. We acquired spectropolarimetric observations of zeta Pup with FORS 2 mounted on the 8 m Antu telescope of the Very Large Telescope to investigate if a magnetic field is indeed present in this star. We show that many spectral lines are highly variable and probably vary with the recently detected period of 1.78 day. No magnetic field is detected in zeta Pup, as no magnetic field measurement has a significance level higher than 2.4 sigma. Still, we studied the probability of a single sinusoidal explaining the variation of the longitudinal magnetic field measurements.},
  language  = {en}
}
@article{ToalaOskinovaGonzalezGalanetal.2016,
  author    = {Toala, Jes{\´u}s Alberto and Oskinova, Lidia M. and Gonzalez-Galan, Ana and Guerrero, Mart{\´i}n A. and Ignace, R. and Pohl, Martin},
  title     = {X-RAY OBSERVATIONS OF BOW SHOCKS AROUND RUNAWAY O STARS. THE CASE OF zeta OPH AND BD+43 degrees 3654},
  series = {The astrophysical journal : an international review of spectroscopy and astronomical physics},
  volume    = {821},
  journal   = {The astrophysical journal : an international review of spectroscopy and astronomical physics},
  publisher = {IOP Publ. Ltd.},
  address   = {Bristol},
  issn      = {0004-637X},
  doi       = {10.3847/0004-637X/821/2/79},
  pages     = {9},
  year      = {2016},
  abstract  = {Non-thermal radiation has been predicted within bow shocks around runaway stars by recent theoretical works. We present X-ray observations toward the runaway stars zeta Oph by Chandra and Suzaku and of BD+43 degrees 3654 by XMM-Newton to search for the presence of non-thermal X-ray emission. We found no evidence of non-thermal emission spatially coincident with the bow shocks; nonetheless, diffuse emission was detected in the vicinity of zeta Oph. After a careful analysis of its spectral characteristics, we conclude that this emission has a thermal nature with a plasma temperature of T approximate to 2 x 10(6) K. The cometary shape of this emission seems to be in line with recent predictions of radiation-hydrodynamic models of runaway stars. The case of BD+43 degrees 3654 is puzzling, as non-thermal emission has been reported in a previous work for this source.},
  language  = {en}
}
@misc{BarniskeOskinovaHamann2016,
  author    = {Barniske, Andreas and Oskinova, Lidia M. and Hamann, Wolf-Rainer},
  title     = {Two extremely luminous WN stars in the Galactic center with circumstellar emission from dust and gas (vol 486, pg 971, 2008)},
  series = {Physical chemistry, chemical physics : a journal of European Chemical Societies},
  volume    = {587},
  journal   = {Physical chemistry, chemical physics : a journal of European Chemical Societies},
  publisher = {EDP Sciences},
  address   = {Les Ulis},
  issn      = {1432-0746},
  doi       = {10.1051/0004-6361/200809568e},
  pages     = {1},
  year      = {2016},
  language  = {en}
}
@misc{Oskinova2016,
  author    = {Oskinova, Lidia M.},
  title     = {Preface: X-ray emission from hot stars and their winds},
  series = {Advances in space research},
  volume    = {58},
  journal   = {Advances in space research},
  publisher = {Elsevier},
  address   = {Oxford},
  issn      = {0273-1177},
  doi       = {10.1016/j.asr.2016.06.031},
  pages     = {679 -- 679},
  year      = {2016},
  language  = {en}
}
@article{GimenezGarciaShenarTorrejonetal.2016,
  author    = {Gimenez-Garcia, Ana and Shenar, Tomer and Torrejon, J. M. and Oskinova, Lidia M. and Martinez-Nunez, S. and Hamann, Wolf-Rainer and Rodes-Roca, J. J. and Gonz{\´a}lez-Galan, A. and Alonso-Santiago, J. and Gonz{\´a}lez-Fern{\´a}ndez, C. and Bernabeu, Guillermo and Sander, Andreas Alexander Christoph},
  title     = {Measuring the stellar wind parameters in IGR J17544-2619 and Vela X-1 constrains the accretion physics in supergiant fast X-ray transient and classical supergiant X-ray binaries},
  series = {Siberian Mathematical Journal},
  volume    = {591},
  journal   = {Siberian Mathematical Journal},
  publisher = {EDP Sciences},
  address   = {Les Ulis},
  issn      = {1432-0746},
  doi       = {10.1051/0004-6361/201527551},
  pages     = {25},
  year      = {2016},
  abstract  = {Aims. To close this gap, we perform a comparative analysis of the optical companion in two important systems: IGR J175442619 (SFXT) and Vela X-1 (SGXB). We analyze the spectra of each star in detail and derive their stellar and wind properties. As a next step, we compare the wind parameters, giving us an excellent chance of recognizing key differences between donor winds in SFXTs and SGXBs. Methods. We use archival infrared, optical and ultraviolet observations, and analyze them with the non-local thermodynamic equilibrium (NLTE) Potsdam Wolf-Rayet model atmosphere code. We derive the physical properties of the stars and their stellar winds, accounting for the influence of X-rays on the stellar winds. Results. We find that the stellar parameters derived from the analysis generally agree well with the spectral types of the two donors: O9I (IGR J17544-2619) and B0.5Iae (Vela X-1). The distance to the sources have been revised and also agree well with the estimations already available in the literature. In IGR J17544-2619 we are able to narrow the uncertainty to d = 3.0 +/- 0.2 kpc. From the stellar radius of the donor and its X-ray behavior, the eccentricity of IGR J17544-2619 is constrained to e < 0.25. The derived chemical abundances point to certain mixing during the lifetime of the donors. An important difference between the stellar winds of the two stars is their terminal velocities (v(infinity) = 1500 km s(-1) in IGR J17544-2619 and v(infinity) = 700 km s(-1) in Vela X-1), which have important consequences on the X-ray luminosity of these sources. Conclusions. The donors of IGR J17544-2619 and Vela X-1 have similar spectral types as well as similar parameters that physically characterize them and their spectra. In addition, the orbital parameters of the systems are similar too, with a nearly circular orbit and short orbital period. However, they show moderate differences in their stellar wind velocity and the spin period of their neutron star which has a strong impact on the X-ray luminosity of the sources. This specific combination of wind speed and pulsar spin favors an accretion regime with a persistently high luminosity in Vela X-1, while it favors an inhibiting accretion mechanism in IGR J17544-2619. Our study demonstrates that the relative wind velocity is critical in class determination for the HMXBs hosting a supergiant donor, given that it may shift the accretion mechanism from direct accretion to propeller regimes when combined with other parameters.},
  language  = {en}
}
@article{PrzybillaFossatiHubrigetal.2016,
  author    = {Przybilla, Norbert and Fossati, Luca and Hubrig, Swetlana and Nieva, M. -F. and Jaervinen, S. P. and Castro, Norberto and Schoeller, M. and Ilyin, Ilya and Butler, Keith and Schneider, F. R. N. and Oskinova, Lidia M. and Morel, T. and Langer, N. and de Koter, A.},
  title     = {B fields in OB stars (BOB): Detection of a magnetic field in the He-strong star CPD-57 degrees 3509},
  series = {Organic letters},
  volume    = {587},
  journal   = {Organic letters},
  publisher = {EDP Sciences},
  address   = {Les Ulis},
  organization    = {BOB Collaboratio},
  issn      = {1432-0746},
  doi       = {10.1051/0004-6361/201527646},
  pages     = {15},
  year      = {2016},
  abstract  = {Methods. Spectropolarimetric observations with FORS2 and HARPSpol are analysed using two independent approaches to quantify the magnetic field strength. A high-S/N FLAMES/GIRAFFE spectrum is analysed using a hybrid non-LTE model atmosphere technique. Comparison with stellar evolution models constrains the fundamental parameters of the star. Results. We obtain a firm detection of a surface averaged longitudinal magnetic field with a maximum amplitude of about 1 kG. Assuming a dipolar configuration of the magnetic field, this implies a dipolar field strength larger than 3.3 kG. Moreover, the large amplitude and fast variation (within about 1 day) of the longitudinal magnetic field implies that CPD-57 degrees 3509 is spinning very fast despite its apparently slow projected rotational velocity. The star should be able to support a centrifugal magnetosphere, yet the spectrum shows no sign of magnetically confined material; in particular, emission in H alpha is not observed. Apparently, the wind is either not strong enough for enough material to accumulate in the magnetosphere to become observable or, alternatively, some leakage process leads to loss of material from the magnetosphere. The quantitative spectroscopic analysis of the star yields an effective temperature and a logarithmic surface gravity of 23 750 +/- 250 K and 4.05 +/- 0.10, respectively, and a surface helium fraction of 0.28 +/- 0.02 by number. The surface abundances of C, N, O, Ne, S, and Ar are compatible with the cosmic abundance standard, whereas Mg, Al, Si, and Fe are depleted by about a factor of 2. This abundance pattern can be understood as the consequence of a fractionated stellar wind. CPD-57 degrees 3509 is one of the most evolved He-strong stars known with an independent age constraint due to its cluster membership.},
  language  = {en}
}
@article{SteinkeOskinovaHamannetal.2016,
  author    = {Steinke, Martin and Oskinova, Lidia M. and Hamann, Wolf-Rainer and Sander, Andreas Alexander Christoph and Liermann, A. and Todt, Helge Tobias},
  title     = {Analysis of the WN star WR102c, its WR nebula, and the associated cluster of massive stars in the Sickle Nebula},
  series = {Tectonophysics : international journal of geotectonics and the geology and physics of the interior of the earth},
  volume    = {588},
  journal   = {Tectonophysics : international journal of geotectonics and the geology and physics of the interior of the earth},
  publisher = {EDP Sciences},
  address   = {Les Ulis},
  issn      = {1432-0746},
  doi       = {10.1051/0004-6361/201527692},
  pages     = {10},
  year      = {2016},
  abstract  = {Context. The massive Wolf-Rayet type star WR102c is located near the Quintuplet Cluster, one of the three massive star clusters in the Galactic centre region. Previous studies indicated that WR102c may have a dusty circumstellar nebula and is among the main ionising sources of the Sickle Nebula associated with the Quintuplet Cluster. Aims. The goals of our study are to derive the stellar parameters of WR102c from the analysis of its spectrum and to investigate its stellar and nebular environment. Methods. We obtained observations with the ESO VLT integral field spectrograph SINFONI in the K-band, extracted the stellar spectra, and analysed them by means of stellar atmosphere models. Results. Our new analysis supersedes the results previously reported for WR102c. We significantly decrease its bolometric luminosity and hydrogen content. We detect four early OB type stars close to WR102c. These stars have radial velocities similar to that of WR102c. We suggest that together with WR102c these stars belong to a distinct star cluster with a total mass of similar to 1000 M-circle dot. We identify a new WR nebula around WR102c in the SINFONI map of the di ff use Br gamma emission and in the HST Pa ff images. The Br gamma line at di ff erent locations is not significantly broadened and similar to the width of nebular emission elsewhere in the H i i region around WR102c. Conclusions. The massive star WR102c located in the Galactic centre region resides in a star cluster containing additional early-type stars. The stellar parameters of WR102c are typical for hydrogen-free WN6 stars. We identify a nebula surrounding WR102c that has a morphology similar to other nebulae around hydrogen-free WR stars, and propose that the formation of this nebula is linked to interaction of the fast stellar wind with the matter ejected at a previous evolutionary stage of WR102c.},
  language  = {en}
}