TY  - CHAP
A1  - Bischof, Ulrike
T1  - Nachlasserschließung im Goethe- und Schiller-Archiv
N2  - Beiträge zum Thema "Nachlässe an Universitäts- und Hochschularchiven sowie Archiven wissenschaftlicher Institutionen" im Rahmen der Frühjahrstagung der Fachgruppe 8: "Archivare an Hochschularchiven und Archiven wissenschaftlicher Institutionen" am 16./17. Juni an der Universität Potsdam.
KW  - Archiv
KW  - Nachlass
Y1  - 2005
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-6081
ER  - 
TY  - CHAP
A1  - Wiemers, Gerald
T1  - Der Nachlass des Erziehungswissenschaftlers und Philosophen Theodor Litt in seiner öffentlichen Wirkung
N2  - Beiträge zum Thema "Nachlässe an Universitäts- und Hochschularchiven sowie Archiven wissenschaftlicher Institutionen" im Rahmen der Frühjahrstagung der Fachgruppe 8: "Archivare an Hochschularchiven und Archiven wissenschaftlicher Institutionen" am 16./17. Juni an der Universität Potsdam.
KW  - Archiv
KW  - Universitätsarchiv
KW  - Nachlass
Y1  - 2005
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-6113
ER  - 
TY  - CHAP
A1  - Schultze, Winfried
T1  - Zufall – Wunsch – Planung : die Erwerbung von Nachlässen zur Bestandsergänzung
N2  - Nachlässe sind persönliches Eigentum und unterliegen deshalb keiner Abgabepflicht. Der Wunsch des Nachlassers bezüglich der weiteren Aufbewahrung seines schriftlichen Erbes ist demzufolge primär gegenüber allen unseren Wünschen. Wir können nicht fordern, sondern nur bitten, uns durch eigene Leistungen anbieten und die zukünftigen Nachlassenden oder deren Erben überzeugen. Die nicht vorhandene institutionelle Zuständigkeit für die Übernahme von Nachlässen erzeugt die Reibungspunkte zwischen den Einrichtungen, die sich um den Erwerb von Nachlässen bemühen: Archive – Bibliotheken – Museen - Sammlungen. Die Wünsche zum Erwerb des Nachlasses einer bestimmten Person – egal ob Wissenschaftler, Künstler oder Politiker – sind demzufolge immer an verschiedenen Orten gleichzeitig vorhanden. Der Zufall entscheidet dann leider meist darüber, an welcher Stelle der Nachlass zukünftig verwahrt und wissenschaftlich genutzt wird. Es stellt sich die Frage, ob wir auf solche Zufälle hoffen und warten sollen, oder ob wir nicht eher eine engagierte – gemeinsam zwischen den Archiven abgestimmte - Erwerbspolitik betrieben sollten.  ------------ Beiträge zum Thema "Nachlässe an Universitäts- und Hochschularchiven sowie Archiven wissenschaftlicher Institutionen" im Rahmen der Frühjahrstagung der Fachgruppe 8: "Archivare an Hochschularchiven und Archiven wissenschaftlicher Institutionen" am 16./17. Juni an der Universität Potsdam.
KW  - Archiv
KW  - Nachlass
Y1  - 2005
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-6098
ER  - 
TY  - CHAP
A1  - Schmid, Gerhard
T1  - Archivarische und bibliothekarische Verfahren der Nachlassbearbeitung
N2  - Beiträge zum Thema "Nachlässe an Universitäts- und Hochschularchiven sowie Archiven wissenschaftlicher Institutionen" im Rahmen der Frühjahrstagung der Fachgruppe 8: "Archivare an Hochschularchiven und Archiven wissenschaftlicher Institutionen" am 16./17. Juni an der Universität Potsdam.
KW  - Archiv
KW  - Universitätsarchiv
KW  - Nachlass
Y1  - 2005
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-6228
ER  - 
TY  - CHAP
A1  - Arnold, Gabriele
T1  - Beiträge zur spektralen Fernerkundung fester planetarer Oberflächen
N2  - Dr. Gabriele Arnold ist Leiterin des Bereichs Optische Informationssyteme am Institut für Planetenforschung des Deutschen Zentrums für Luft- und Raumfahrt (DLR) in Berlin-Adlershof  <hr>  Interdisziplinäres Zentrum für Musterdynamik und Angewandte Fernerkundung Workshop vom 9. - 10. Februar 2006
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-7235
N1  - [Poster]
ER  - 
TY  - CHAP
A1  - Doktor, Daniel
A1  - Badeck, Franz-Werner
A1  - Bondeau, Alberte
A1  - Koslowsky, Dirk
A1  - Schaber, Jörg
A1  - McAllister, Murdock
T1  - Using satellite imagery and ground observations to quantify the effect of intra-annually changing temperature patterns on spring time phenology
N2  - Interdisziplinäres Zentrum für Musterdynamik und Angewandte Fernerkundung Workshop vom 9. - 10. Februar 2006
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-7244
N1  - [Poster]
ER  - 
TY  - CHAP
A1  - Domsch, Horst
T1  - Prägnante räumlich-zeitliche Muster einer landwirtschaftlich genutzten Fläche
N2  - In ihrem Bemühen, landwirtschaftliche Flächen standortgerecht zu bewirtschaften, sammelt eine zunehmende Anzahl landwirtschaftlicher Betriebe Informationen über die räumlich-zeitliche Verteilung von Boden- und Pflanzenmerkmalen auf ihren Schlägen. Diese Informationen dienen unmittelbar (Echtzeitansatz) oder mittelbar (Kartenansatz) zur Dosierung von Dünge- und Pflanzenschutzmitteln (Präzise Landbewirtschaftung). Zur Datensammlung werden vorrangig fahrzeuggestützte Sensoren und VIS- und NIR-Luftbilder, aufgenommen aus Sportflugzeugen, verwendet. Erste Betriebe erwerben von Dienstleistungsunternehmen aufbereitete Satelliten-Fernerkundungsdaten. Die landwirtschaftliche und agrartechnische Forschung ist bestrebt, die grundlegenden Muster (z.B. des Ertragspotentials) zu erkennen und damit den Aufwand der Betriebe für eine regelmäßige Informationserfassung gering zu halten.  <hr>  Interdisziplinäres Zentrum für Musterdynamik und Angewandte Fernerkundung Workshop vom 9. - 10. Februar 2006
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-7257
N1  - [Poster]
ER  - 
TY  - CHAP
A1  - Kühling, Matthias
A1  - Märker, Michael
A1  - Zehe, Erwin
ED  - Gzik, Axel
ED  - Hochschild, Volker
ED  - Schneider, Ingo
ED  - Schröder, Boris
T1  - Musterdynamik und Fernerkundung in der Döberitzer Heide : [Poster]
N2  - Mit der politischen Wende in den Staaten des ehemaligen Ostblockes wurde für viele militärisch genutzte Flächen ein tiefgreifender Nutzungswandel eingeleitet. Truppenübungsplätze als stark gestörte Bestandteile unserer Kulturlandschaft weisen auf großen Flächen naturschutzfachlich wertvolle Habitatmosaike mit speziellen Lebensgemeinschaften auf. Der Nutzungswandel ist mit einer Veränderung der Vegetationsstrukturen (Sukzession) und weiteren landschaftsökologischen Prozessen verbunden.  Der ehemalige Truppenübungsplatz Döberitz im Norden der Landeshauptstadt Potsdam kann auf eine lange militärische Nutzungsgeschichte verweisen (erste Manöver des Soldatenkönigs im Jahr 1713). Nach 1992 wurden das NSG Döberitzer Heide (3.415 ha) und das NSG Ferbitzer Bruch (1.155 ha) ausgewiesen. Als Schutzgebiete nach der Vogelschutzrichtlinie sind sie Bestandteile des kohärenten Schutzgebietssystems Natura 2000 der europäischen Gemeinschaft. Trotz des Schutzstatus und der militärischen Altlasten unterliegt das Gebiet als größte zusammenhängende Naturfläche im engeren Verflechtungsraum des Landes Brandenburg einem hohen Nutzungsdruck.  <hr>  Interdisziplinäres Zentrum für Musterdynamik und Angewandte Fernerkundung Workshop vom 9. - 10. Februar 2006
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-7277
ER  - 
TY  - CHAP
A1  - Märker, Michael
A1  - Schröder-Esselbach, Boris
A1  - Capolongo, Domenico
A1  - Bentivenga, Mario
T1  - Geomorphological and pedological processes in badland areas of Southern Italy and their interaction with Mediterranean vegetation
N2  - Interdisziplinäres Zentrum für Musterdynamik und Angewandte Fernerkundung Workshop vom 9. - 10. Februar 2006
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-7288
N1  - [Poster]
ER  - 
TY  - CHAP
A1  - Bergmann, Kirsten
A1  - Kopp, Stefan
T1  - Verbal or visual? : How information is distributed across speech and gesture in spatial dialog
N2  - In spatial dialog like in direction giving humans make frequent use of speechaccompanying gestures. Some gestures convey largely the same information as speech while others complement speech. This paper reports a study on how speakers distribute meaning across speech and gesture, and depending on what factors. Utterance meaning and the wider dialog context were tested by statistically analyzing a corpus of direction-giving dialogs. Problems of speech production (as indicated by discourse markers and disfluencies), the communicative goals, and the information status were found to be influential, while feedback signals by the addressee do not have any influence.
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-10375
ER  - 
TY  - CHAP
A1  - Diderichsen, Philip
T1  - Cross recurrence quantification analysis of indefinite anaphora in Swedish dialog :  an eye-tracking pilot experiment
N2  - A new method is used in an eye-tracking pilot experiment which shows that it is possible to detect differences in common ground associated with the use of minimally different types of indefinite anaphora. Following Richardson and Dale (2005), cross recurrence quantification analysis (CRQA) was used to show that the tandem eye movements of two Swedish-speaking interlocutors are slightly more coupled when they are using fully anaphoric indefinite expressions than when they are using less anaphoric indefinites. This shows the potential of CRQA to detect even subtle processing differences in ongoing discourse.
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-10388
ER  - 
TY  - CHAP
A1  - Lücking, Andy
A1  - Rieser, Hannes
A1  - Staudacher, Marc
T1  - Multi-modal integration for gesture and speech
N2  - Demonstratives, in particular gestures that "only" accompany speech, are not a big issue in current theories of grammar. If we deal with gestures, fixing their function is one big problem, the other one is how to integrate the representations originating from different channels and, ultimately, how to determine their composite meanings. The growing interest in multi-modal settings, computer simulations, human-machine interfaces and VRapplications increases the need for theories ofmultimodal structures and events. In our workshopcontribution we focus on the integration of multimodal contents and investigate different approaches dealing with this problem such as Johnston et al. (1997) and Johnston (1998), Johnston and Bangalore (2000), Chierchia (1995), Asher (2005), and Rieser (2005).
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-10393
ER  - 
TY  - CHAP
A1  - Saget, Sylvie
A1  - Guyomard, Marc
T1  - Goal-oriented dialog as a collaborative subordinated activity involving collective acceptance
N2  - Modeling dialog as a collaborative activity consists notably in specifying the contain of the Conversational Common Ground and the kind of social mental state involved. In previous work (Saget, 2006), we claim that Collective Acceptance is the proper social attitude for modeling Conversational Common Ground in the particular case of goal-oriented dialog. We provide a formalization of Collective Acceptance, besides elements in order to integrate this attitude in a rational model of dialog are provided; and finally, a model of referential acts as being part of a collaborative activity is provided. The particular case of reference has been chosen in order to exemplify our claims.
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-10420
ER  - 
TY  - CHAP
A1  - DeVault, David
A1  - Stone, Matthew
T1  - Scorekeeping in an uncertain language game
N2  - Received views of utterance context in pragmatic theory characterize the occurrent subjective states of interlocutors using notions like common knowledge or mutual belief. We argue that these views are not compatible with the uncertainty and robustness of context-dependence in human–human dialogue. We present an alternative characterization of utterance context as objective and normative. This view reconciles the need for uncertainty with received intuitions about coordination and meaning in context, and can directly inform computational approaches to dialogue.
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-10448
ER  - 
TY  - CHAP
A1  - Kaufmann, Hermann
T1  - Abbildende Spektrometrie
BT  - [Die neuen diagnostischen Möglichkeiten der Programme ARES und ENMAP bei der Erfassung von Oberflächenprozessen]
N2  - Interdisziplinäres Zentrum für Musterdynamik und Angewandte Fernerkundung Workshop vom 9. - 10. Februar 2006
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-7104
ER  - 
TY  - CHAP
A1  - Sommer, Michael
T1  - Nicht-invasive Methoden in der Bodenlandschaftsforschung
BT  - Konzeption und Projekte
N2  - Der Referent ist Leiter des Institutes für Bodenlandschaftsforschung am Leibniz-Zentrum für Agrarlandschaftsforschung (ZALF) e. V. in Müncheberg.
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-7117
N1  - Interdisziplinäres Zentrum für Musterdynamik und Angewandte Fernerkundung Workshop vom 9. - 10. Februar 2006
ER  - 
TY  - CHAP
A1  - Zehe, Erwin
A1  - Bronstert, Axel
A1  - Itzerott, Sibylle
A1  - Bárdossy, András
A1  - Ihringer, Jürgen
T1  - Hochwasservorhersage, Großhangbewegungen, Schadstofftransport
BT  - IMAF-relevante Projektbeispiele und Vorhaben am Institut für Geoökologie
N2  - Interdisziplinäres Zentrum für Musterdynamik und Angewandte Fernerkundung Workshop vom 9. - 10. Februar 2006
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-7128
ER  - 
TY  - CHAP
A1  - Kuhnert, Matthias
A1  - Güntner, Andreas
A1  - Klann, Mechthild
A1  - Martin Garrido, F.
A1  - Zillgens, Birgit
T1  - Methods for spatial pattern comparison in distributed hydrological modelling : [Poster]
N2  - The rigorous development, application and validation of distributed hydrological models obligates to evaluate data in a spatially distributed way. In particular, spatial model predictions such as the distribution of soil moisture, runoff generating areas or nutrient-contributing areas or erosion rates, are to be assessed against spatially distributed observations. Also model inputs, such as the distribution of modelling units derived by GIS and remote sensing analyses, should be evaluated against groundbased observations of landscape characteristics. So far, however, quantitative methods of spatial field comparison have rarely been used in hydrology.  In this paper, we present algorithms that allow to compare observed and simulated spatial hydrological data. The methods can be applied for binary and categorical data on regular grids. They comprise cell-by-cell algorithms, cell-neighbourhood approaches that account for fuzziness of location, and multi-scale algorithms that evaluate the similarity of spatial fields with changing resolution. All methods provide a quantitative measure of the similarity of two maps. The comparison methods are applied in two mountainous catchments in southern Germany (Brugga, 40 km<sup>2) and Austria (Löhnersbach, 16 km<sup>2). As an example of binary hydrological data, the distribution of saturated areas is analyzed in both catchments. For categorical data, vegetation zones that are associated with different runoff generation mechanisms are analyzed in the Löhnersbach. Mapped spatial patterns are compared to simulated patterns from terrain index calculations and from satellite image analysis. It is discussed how particular features of visual similarity between the spatial fields are captured by the quantitative measures, leading to recommendations on suitable algorithms in the context of evaluating distributed hydrological models.
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-7160
N1  - Interdisziplinäres Zentrum für Musterdynamik und Angewandte Fernerkundung Workshop vom 9. - 10. Februar 2006
ER  - 
TY  - CHAP
A1  - Wegehenkel, Martin
T1  - Die Nutzung von Fernerkundungsdaten in der Wasserhaushaltsmodellierung
BT  - ein Review
N2  - Die Präsentation gibt zuerst einen Überblick über mögliche Parameter für die Wasserhaushaltsmodellierung, die aus Fernerkundungs(FE)-daten generell abgeleitet werden können. Bei der Beschreibung der Ableitungsverfahren dieser Parameter aus (FE)-Daten wird auf die Landnutzung, Vegetationsindices und die reale Evapotranspiration (ETr) fokussiert. Die Verfahren zur Bestimmung der ETr aus optischen FE-Daten lassen grob wie folgt gliedern : • Direkte Ableitung der Evapotranspiration aus radiometrisch bestimmten Oberflächen-temperaturen • Ableitung von Modellinputdaten wie z.B. Globalstrahlung, Albedo, Blattflächeniondex LAI und NDVI aus FE-Daten zur Anwendung von SoilVegetation-AtmosphereTransfer- und Energiebilanzmodellen wie z.B. SEBAL (Bastiaansen et al . 1998) • Kombinierte Anwendung verschiedenster Sensoren wie SAR-ERS1, LANDSAT-TM, NOAA-AHVRR mit SVAT-Modellen und hydrologischen Einzugsgebietsmodellen Die Validierung dieser Methoden wurde in verschiedenen Messkampagnen wie z.B. Lo-trex10E-HIBE, FIFE oder HAPEX-Sahel durchgeführt. Dabei wurde die aus dem entspre-chenden Sensor abgeleitete ETr mit gemessenen ETr-Raten von Ankerstationen innerhalb eines definierten Gebietes verglichen. Diese Ankerstationen leiteten die ETr aus Profil-, Ed-dy-Flux-, oder Szintillometermessungen ab. Durchgängige längere Zeitreihen der ETr sind nur mit FE-Daten mit hoher Wiederholungsrate wie z.B. NOAA-AVHRR, MODIS hoher Zeitauflösung möglich Mit Landsat-TM z.B. ergeben sich dagegen nur „Snap Shots“ der ETr von einzelnen Tagen. Daher wurden oftmals Multisensorverfahren d.h. Kombination von z.B. Landsat-TM mit NOAA-AVHRR eingesetzt oder die FE-Daten nur für die Erhebung zeitin-varianter Eingangsdaten (z.B. Landnutzung) und zur raumbezogenen Validierung der ETr-Berechnungen von hydrologischen Modellen verwendet. Im zweiten Teil des Vortrags wird ein Anwendungsbeispiel für den Versuch einer räumliche Validierung eines Wasserhaus-haltsmodells über NDVI-ETr-Datenprodukte aus Landsat-TM5-Daten für das Stobbergebiet. Ein weiteres Anwendungsbeispiel für die Einbindung von Landnutzungsdatenprodukten aus Landsat-TM5-Daten in die Wasserhaushaltmodellierung für das Ucker-Einzugsgebiet schliesst den Vortrag ab.  <hr>  Dokument 1: Foliensatz | Dokument 2: Abstract  <hr>  Interdisziplinäres Zentrum für Musterdynamik und Angewandte Fernerkundung Workshop vom 9. - 10. Februar 2006
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-7050
ER  - 
TY  - CHAP
A1  - Schulz, Karsten
T1  - Die Bedeutung räumlicher Strukturen und Muster für das hydrologische Prozessgeschehen
N2  - Der Referent ist stellvertretender Leiter des Departments Angewandte Landschaftsökologie des UFZ - Umweltforschungszentrum Leipzig-Halle am Fachbereich Umweltsystemmodellierung <hr>  Interdisziplinäres Zentrum für Musterdynamik und Angewandte Fernerkundung Workshop vom 9. - 10. Februar 20066
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-7087
ER  - 
TY  - CHAP
A1  - Wolska, Magdalena
A1  - Kruijff-Korbayová, Ivana
T1  - Modeling anaphora in informal mathematical dialogue
N2  - We analyze anaphoric phenomena in the context of building an input understanding component for a conversational system for tutoring mathematics. In this paper, we report the results of data analysis of two sets of corpora of dialogs on mathematical theorem proving. We exemplify anaphoric phenomena, identify factors relevant to anaphora resolution in our domain and extensions to the input interpretation component to support it.
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-10455
ER  - 
TY  - CHAP
A1  - Kempson, Ruth
A1  - Cann, Ronnie
T1  - Dialogue pressures and syntactic change
N2  - On the basis of the Dynamic Syntax framework, this paper argues that the production pressures in dialogue determining alignment effects and given versus new informational effects also drive the shift from case-rich free word order systems without clitic pronouns into systems with clitic pronouns with rigid relative ordering. The paper introduces assumptions of Dynamic Syntax, in particular the building up of interpretation through structural underspecification and update, sketches the attendant account of production with close coordination of parsing and production strategies, and shows how what was at the Latin stage a purely pragmatic, production-driven decision about linear ordering becomes encoded in the clitics in theMedieval Spanish system which then through successive steps of routinization yield the modern systems with immediately pre-verbal fixed clitic templates.
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-10469
ER  - 
TY  - CHAP
A1  - Vlugter, Peter
A1  - Knott, Alistair
T1  - A multi-speaker dialogue system for computer-aided language learning
N2  - The main topic of this paper is how to configure a dialogue system to support computer-aided language learning. The paper also serves to introduce our new multi-speaker dialogue system, and highlight some of its novel features.
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-10208
ER  - 
TY  - CHAP
A1  - Karagjosova, Elena
T1  - Correction and acceptance by contrastive focus
N2  - An account is presented of the focus properties, common ground effect and dialogue behaviour of the accented German discourse marker "doch" and the accented sentence negation "nicht". It is argued that "doch" and "nicht" evoke as a focus alternative the logical complement of the proposition expressed by the sentence in which they occur, and that an analysis in terms of contrastive focus accounts for their effect on the common ground and their function in dialogue.
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-10258
ER  - 
TY  - CHAP
A1  - Macura, Zoran
A1  - Ginzburg, Jonathan
T1  - Acquiring words across generations : introspectively or interactively?
N2  - How does a shared lexicon arise in population of agents with differing lexicons, and how can this shared lexicon be maintained over multiple generations? In order to get some insight into these questions we present an ALife model in which the lexicon dynamics of populations that possess and lack metacommunicative interaction (MCI) capabilities are compared. We ran a series of experiments on multi-generational populations whose initial state involved agents possessing distinct lexicons. These experiments reveal some clear differences in the lexicon dynamics of populations that acquire words solely by introspection contrasted with populations that learn using MCI or using a mixed strategy of introspection and MCI. The lexicon diverges at a faster rate for an introspective population, eventually collapsing to one single form which is associated with all meanings. This contrasts sharply with MCI capable populations in which a lexicon is maintained, where every meaning is associated with a unique word. We also investigated the effect of increasing the meaning space and showed that it speeds up the lexicon divergence for all populations irrespective of their acquisition method.
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-10408
ER  - 
TY  - CHAP
A1  - Thomas, Kavita E.
T1  - Modelling Correction Signalled by "But" in Dialogue
N2  - Claiming that cross-speaker "but" can signal correction in dialogue, we start by describing the types of corrections "but" can communicate by focusing on the Speech Act (SA) communicated in the previous turn and address the ways in which "but" can correct what is communicated. We address whether "but" corrects the proposition, the direct SA or the discourse relation communicated in the previous turn. We will also briefly address other relations signalled by cross-turn "but". After presenting a typology of the situations "but" can correct, we will address how these corrections can be modelled in the Information State model of dialogue, motivating this work by showing how it can be used to potentially avoid misunderstandings. We wrap up by showing how the model presented here updates beliefs in the Information State representation of the dialogue and can be used to facilitate response deliberation.
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-10308
ER  - 
TY  - CHAP
A1  - Beyssade, Claire
A1  - Marandin, Jean-Marie
T1  - From complex to simple speech acts : a bidimensional analysis of illocutionary
N2  - We present a new analysis of illocutionary forces in dialogue. We analyze them as complex conversational moves involving two dimensions: what Speaker commits herself to and what she calls on Addressee to perform. We start from the analysis of speech acts such as confirmation requests or whimperatives, and extend the analysis to seemingly simple speech acts, such as statements and queries. Then, we show how to integrate our proposal in the framework of the Grammar for Conversation (Ginzburg, to app.), which is adequate for modelling agents' information states and how they get updated.
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-10319
ER  - 
TY  - CHAP
A1  - Hara, Yurie
T1  - Question intonation and lexicalized bias expression
N2  - This paper examines the interaction between different utterance types and the Japanese modal particle darou, and proposes that the decision-theoretic semantics accounts for the interaction among darou, sentence types and intonation.
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-10323
ER  - 
TY  - CHAP
A1  - Artstein, Ron
A1  - Poesio, Massimo
T1  - Identifying reference to abstract objects in dialogue
N2  - In two experiments, many annotators marked antecedents for discourse deixis as unconstrained regions of text. The experiments show that annotators do converge on the identity of these text regions, though much of what they do can be captured by a simple model. Demonstrative pronouns are more likely than definite descriptions to be marked with discourse antecedents. We suggest that our methodology is suitable for the systematic study of discourse deixis.
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-10357
ER  - 
TY  - CHAP
A1  - Lascarides, Alex
A1  - Stone, Matthew
T1  - Formal semantics for iconic gesture
N2  - We present a formal analysis of iconic coverbal gesture. Our model describes the incomplete meaning of gesture that’s derivable from its form, and the pragmatic reasoning that yields a more specific interpretation. Our formalism builds on established models of discourse interpretation to capture key insights from the descriptive literature on gesture: synchronous speech and gesture express a single thought, but while the form of iconic gesture is an important clue to its interpretation, the content of gesture can be resolved only by linking it to its context.
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-10330
ER  - 
TY  - CHAP
A1  - Lücking, Andy
A1  - Rieser, Hannes
A1  - Staudacher, Marc
T1  - SDRT and multi-modal situated communication
N2  - Classical SDRT (Asher and Lascarides, 2003) discussed essential features of dialogue like adjacency pairs or corrections and up-dating. Recent work in SDRT (Asher, 2002, 2005) aims at the description of natural dialogue. We use this work to model situated communication, i.e. dialogue, in which sub-sentential utterances and gestures (pointing and grasping) are used as conventional modes of communication. We show that in addition to cognitive modelling in SDRT, capturing mental states and speech-act related goals, special postulates are needed to extract meaning out of contexts. Gestural meaning anchors Discourse Referents in contextually given domains. Both sorts of meaning are fused with the meaning of fragments to get at fully developed dialogue moves. This task accomplished, the standard SDRT machinery, tagged SDRSs, rhetorical relations, the up-date mechanism, and the Maximize Discourse Coherence constraint generate coherent structures. In sum, meanings from different verbal and non-verbal sources are assembled using extended SDRT to form coherent wholes.
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-10348
ER  - 
TY  - CHAP
A1  - Kranstedt, Alfred
A1  - Lücking, Andy
A1  - Pfeiffer, Thies
A1  - Rieser, Hannes
A1  - Staudacher, Marc
T1  - Measuring and reconstructing pointing in visual contexts
N2  - We describe an experiment to gather original data on geometrical aspects of pointing. In particular, we are focusing upon the concept of the pointing cone, a geometrical model of a pointing’s extension. In our setting we employed methodological and technical procedures of a new type to integrate data from annotations as well as from tracker recordings. We combined exact information on position and orientation with rater’s classifications. Our first results seem to challenge classical linguistic and philosophical theories of demonstration in that they advise to separate pointings from reference.
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-10362
ER  - 
TY  - CHAP
A1  - Mills, Gregory J.
A1  - Healey, Patrick G. T.
T1  - Clarifying spatial descriptions : local and global effects on semantic co-ordination
N2  - A key problem for models of dialogue is to explain the mechanisms involved in generating and responding to clarification requests. We report a 'Maze task' experiment that investigates the effect of 'spoof' clarification requests on the development of semantic co-ordination. The results provide evidence of both local and global semantic co-ordination phenomena that are not captured by existing dialogue co-ordination models.
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-10414
ER  - 
TY  - CHAP
A1  - Dzikovska, Myroslava O.
A1  - Callaway, Charles B.
A1  - Stone, Matthew
A1  - Moore, Johanna D.
T1  - Understanding student input for tutorial dialogue in procedural domains
N2  - We present an analysis of student language input in a corpus of tutoring dialogue in the domain of symbolic differentiation. Our focus on procedural tutoring makes the dialogue comparable to collaborative problem-solving (CPS). Existing CPS models describe the process of negotiating plans and goals, which also fits procedural tutoring. However, we provide a classification of student utterances and corpus annotation which shows that approximately 28% of non-trivial student language in this corpus is not accounted for by existing models, and addresses other functions, such as evaluating past actions or correcting mistakes. Our analysis can be used as a foundation for improving models of tutoring dialogue.
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-10193
ER  - 
TY  - CHAP
A1  - Ohrnberger, Matthias
A1  - Wassermann, Joachim
A1  - Richter, Gudrun
T1  - Automatic detection and classification of seismic signals for monitoring purposes
N2  - Interdisziplinäres Zentrum für Musterdynamik und Angewandte Fernerkundung Workshop vom 9. - 10. Februar 2006
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-7294
N1  - [Poster]
ER  - 
TY  - CHAP
A1  - Popp, Alexander
A1  - Blaum, Niels
A1  - Domptail, Stephanie
A1  - Herpel, Nicole
A1  - Gröngröft, Alexander
A1  - Hoffman, T. T.
A1  - Jürgens, Norbert
A1  - Milton, Sue
A1  - Nuppenau, Ernst-August
A1  - Rossmanith, Eva
A1  - Schmidt, Michael
A1  - Vogel, Melanie
A1  - Vohland, Katrin
A1  - Jeltsch, Florian
T1  - From satellite imagery to soil-plant interactions
BT  - integrating disciplines and scales in process based simulation models
N2  - Decisions for the conservation of biodiversity and sustainable management of natural resources are typically related to large scales, i.e. the landscape level. However, understanding and predicting the effects of land use and climate change on scales relevant for decision-making requires to include both, large scale vegetation dynamics and small scale processes, such as soil-plant interactions. Integrating the results of multiple BIOTA subprojects enabled us to include necessary data of soil science, botany, socio-economics and remote sensing into a high resolution, process-based and spatially-explicit model. Using an example from a sustainably-used research farm and a communally used and degraded farming area in semiarid southern Namibia we show the power of simulation models as a tool to integrate processes across disciplines and scales.
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-7302
N1  - Interdisziplinäres Zentrum für Musterdynamik und Angewandte Fernerkundung Workshop vom 9. - 10. Februar 2006.

[Poster]
ER  - 
TY  - CHAP
A1  - Rossmanith, Eva
A1  - Blaum, Niels
A1  - Keil, Manfred
A1  - Langerwisch, F.
A1  - Meyer, Jork
A1  - Popp, Alexander
A1  - Schmidt, Michael
A1  - Schultz, Christoph
A1  - Schwager, Monika
A1  - Vogel, Melanie
A1  - Wasiolka, Bernd
A1  - Jeltsch, Florian
T1  - Scaling up local population dynamics to regional scales
BT  - an integrated approach
N2  - In semi-arid savannas, unsustainable land use can lead to degradation of entire landscapes, e.g. in the form of shrub encroachment. This leads to habitat loss and is assumed to reduce species diversity. In BIOTA phase 1, we investigated the effects of land use on population dynamics on farm scale. In phase 2 we scale up to consider the whole regional landscape consisting of a diverse mosaic of farms with different historic and present land use intensities. This mosaic creates a heterogeneous, dynamic pattern of structural diversity at a large spatial scale. Understanding how the region-wide dynamic land use pattern affects the abundance of animal and plant species requires the integration of processes on large as well as on small spatial scales. In our multidisciplinary approach, we integrate information from remote sensing, genetic and ecological field studies as well as small scale process models in a dynamic region-wide simulation tool.  <hr>  Interdisziplinäres Zentrum für Musterdynamik und Angewandte Fernerkundung Workshop vom 9. - 10. Februar 2006.
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-7320
N1  - [Poster]
ER  - 
TY  - CHAP
A1  - Zeilinger, Gerold
A1  - Mutti, Maria
A1  - Strecker, Manfred
A1  - Rehak, Katrin
A1  - Bookhagen, Bodo
A1  - Schwab, Marco
T1  - Integration of digital elevation models and satellite images to investigate geological processes.
N2  - In order to better understand the geological boundary conditions for ongoing or past surface processes geologists face two important questions: 1) How can we gain additional knowledge about geological processes by analyzing digital elevation models (DEM) and satellite images and 2) Do these efforts present a viable approach for more efficient research. Here, we will present case studies at a variety of scales and levels of resolution to illustrate how we can substantially complement and enhance classical geological approaches with remote sensing techniques. Commonly, satellite and DEM based studies are being used in a first step of assessing areas of geologic interest. While in the past the analysis of satellite imagery (e.g. Landsat TM) and aerial photographs was carried out to characterize the regional geologic characteristics, particularly structure and lithology, geologists have increasingly ventured into a process-oriented approach. This entails assessing structures and geomorphic features with a concept that includes active tectonics or tectonic activity on time scales relevant to humans. In addition, these efforts involve analyzing and quantifying the processes acting at the surface by integrating different remote sensing and topographic data (e.g. SRTM-DEM, SSM/I, GPS, Landsat 7 ETM, Aster, Ikonos…). A combined structural and geomorphic study in the hyperarid Atacama desert demonstrates the use of satellite and digital elevation data for assessing geological structures formed by long-term (millions of years) feedback mechanisms between erosion and crustal bending (Zeilinger et al., 2005). The medium-term change of landscapes during hundred thousands to millions years in a more humid setting is shown in an example from southern Chile. Based on an analysis of rivers/watersheds combined with landscapes parameterization by using digital elevation models, the geomorphic evolution and change in drainage pattern in the coastal Cordillera can be quantified and put into the context of seismotectonic segmentation of a tectonically active region. This has far-reaching implications for earthquake rupture scenarios and hazard mitigation (K. Rehak, see poster on IMAF Workshop). Two examples illustrate short-term processes on decadal, centennial and millennial time scales: One study uses orogen scale precipitation gradients derived from remotely sensed passive microwave data (Bookhagen et al., 2005a). They demonstrate how debris flows were triggered as a response of slopes to abnormally strong rainfall in the interior parts of the Himalaya during intensified monsoons. The area of the orogen that receives high amounts of precipitation during intensified monsoons also constitutes numerous landslide deposits of up to 1km<sup>3 volume that were generated during intensified monsoon phase at about 27 and 9 ka (Bookhagen et al., 2005b). Another project in the Swiss Alps compared sets of aerial photographs recorded in different years. By calculating high resolution surfaces the mass transport in a landslide could be reconstructed (M. Schwab, Universität Bern). All these examples, although representing only a short and limited selection of projects using remote sense data in geology, have as a common approach the goal to quantify geological processes. With increasing data resolution and new sensors future projects will even enable us to recognize more patterns and / or structures indicative of geological processes in tectonically active areas. This is crucial for the analysis of natural hazards like earthquakes, tsunamis and landslides, as well as those hazards that are related to climatic variability. The integration of remotely sensed data at different spatial and temporal scales with field observations becomes increasingly important. Many of presently highly populated places and increasingly utilized regions are subject to significant environmental pressure and often constitute areas of concentrated economic value. Combined remote sensing and ground-truthing in these regions is particularly important as geologic, seismicity and hydrologic data may be limited here due to the recency of infrastructural development. Monitoring ongoing processes and evaluating the remotely sensed data in terms of recurrence of events will greatly enhance our ability to assess and mitigate natural hazards.  <hr>  Dokument 1: Foliensatz | Dokument 2: Abstract  <hr>  Interdisziplinäres Zentrum für Musterdynamik und Angewandte Fernerkundung Workshop vom 9. - 10. Februar 2006
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-7063
ER  - 
TY  - CHAP
A1  - Rehak, Katrin
A1  - Strecker, Manfred
A1  - Echtler, Helmut Peter
T1  - DEM supported tectonic geomorphology : the Coastal Cordillera of the South-Central Chilean active margin ; [Poster]
N2  - Fluvial systems are one of the major features shaping a landscape. They adjust to the prevailing tectonic and climatic setting and therefore are very sensitive markers of changes in these systems. If their response to tectonic and climatic forcing is quantified and if the climatic signal is excluded, it is possible to derive a local deformation history. Here, we investigate fluvial terraces and erosional surfaces in the southern Chilean forearc to assess a long-term geomorphic and hence tectonic evolution. Remote sensing and field studies of the Nahuelbuta Range show that the long-term deformation of the Chilean forearc is manifested by breaks in topography, sequences of differentially uplifted marine, alluvial and strath terraces as well as tectonically modified river courses and drainage basins. We used SRTM-90-data as basic elevation information for extracting and delineating drainage networks. We calculated hypsometric curves as an indicator for basin uplift, stream-length gradient indices to identify stream segments with anomalous slopes, and longitudinal river profiles as well as DS-plots to identify knickpoints and other anomalies. In addition, we investigated topography with elevation-slope graphs, profiles, and DEMs to reveal erosional surfaces. During the first field trip we already measured palaeoflow directions, performed pebble counting and sampled the fluvial terraces in order to apply cosmogenic nuclide dating (<sup>10Be, <sup>26Al) as well as provenance analyses. Our preliminary analysis of the Coastal Cordillera indicates a clear segmentation between the northern and southern parts of the Nahuelbuta Range. The Lanalhue Fault, a NW-SE striking fault zone oblique to the plate boundary, defines the segment boundary. Furthermore, we find a complex drainage re-organisation including a drainage reversal and wind gap on the divide between the Tirúa and Pellahuén basins east of the town Tirúa. The coastal basins lost most of their Andean sediment supply areas that existed in Tertiary and in part during early Pleistocene time. Between the Bío-Bío and Imperial rivers no Andean river is recently capable to traverse the Coastal Cordillera, suggesting ongoing Quaternary uplift of the entire range. From the spatial distribution of geomorphic surfaces in this region two uplift signals may be derived: (1) a long-term differential uplift process, active since the Miocene and possibly caused by underplating of subducted trench sediments, (2) a younger, local uplift affecting only the northern part of the Nahuelbuta Range that may be caused by the interaction of the forearc with the subduction of the Mocha Fracture Zone at the latitude of the Arauco peninsula. Our approach thus provides results in our attempt to decipher the characteristics of forearc development of active convergent margins using long-term geomorphic indicators. Furthermore, it is expected that our ongoing assessment will constrain repeatedly active zones of deformation.  <hr>  Interdisziplinäres Zentrum für Musterdynamik und Angewandte Fernerkundung Workshop vom 9. - 10. Februar 2006
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-7224
ER  - 
TY  - CHAP
A1  - Reimer, O.
A1  - Aharonian, Felix A.
A1  - Hinton, J.
A1  - Hofmann, W.
A1  - Hoppe, S.
A1  - Raue, M.
A1  - Reimer, A.
T1  - VHE gamma-rays from Westerlund 2 and implications for the inferred energetics
N2  - The H.E.S.S. collaboration recently reported the discovery of VHE γ-ray emission coincident with the young stellar cluster Westerlund 2. This system is known to host a population of hot, massive stars, and, most particularly, the WR binary WR 20a. Particle acceleration to TeV energies in Westerlund 2 can be accomplished in several alternative scenarios, therefore we only discuss energetic constraints based on the total available kinetic energy in the system, the actual mass loss rates of respective cluster members, and implied gamma-ray production from processes such as inverse Compton scattering or neutral pion decay. From the inferred gammaray luminosity of the order of 1035erg/s, implications for the efficiency of converting available kinetic energy into non-thermal radiation associated with stellar winds in the Westerlund 2 cluster are discussed under consideration of either the presence or absence of wind clumping.
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-18172
ER  - 
TY  - CHAP
A1  - Hirschi, Raphael
T1  - The impact of reduced mass loss rates on the evolution of massive stars
N2  - Mass loss is a very important aspect of the life of massive stars. After briefly reviewing its importance, we discuss the impact of the recently proposed downward revision of mass loss rates due to clumping (difficulty to form Wolf-Rayet stars and production of critically rotating stars). Although a small reduction might be allowed, large reduction factors around ten are disfavoured. We then discuss the possibility of significant mass loss at very low metallicity due to stars reaching break-up velocities and especially due to the metal enrichment of the surface of the star via rotational and convective mixing. This significant mass loss may help the first very massive stars avoid the fate of pair-creation supernova, the chemical signature of which is not observed in extremely metal poor stars. The chemical composition of the very low metallicity winds is very similar to that of the most metal poor star known to date, HE1327-2326 and offer an interesting explanation for the origin of the metals in this star. We also discuss the importance of mass loss in the context of long and soft gamma-ray bursts and pair-creation supernovae. Finally, we would like to stress that mass loss in cooler parts of the HR-diagram (luminous blue variable and yellow and red supergiant stages) are much more uncertain than in the hot part. More work needs to be done in these areas to better constrain the evolution of the most massive stars.
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17616
ER  - 
TY  - CHAP
A1  - Fullerton, A. W.
A1  - Massa, D. L.
A1  - Prinja, R. K.
T1  - Revised mass-loss rates for O stars from the Pv resonance line
N2  - The P v λλ1118, 1128 resonance doublet is an extraordinarily useful diagnostic of O-star winds, because it bypasses the traditional problems associated with determining mass-loss rates from UV resonance lines. We discuss critically the assumptions and uncertainties involved with using P v to diagnose mass-loss rates, and conclude that the large discrepancies between massloss rates determined from P v and the rates determined from “density squared” emission processes pose a significant challenge to the “standard model” of hot-star winds. The disparate measurements can be reconciled if the winds of O-type stars are strongly clumped on small spatial scales, which in turn implies that mass-loss rates based on Hα or radio emission are too large by up to an order of magnitude.
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17647
ER  - 
TY  - CHAP
A1  - Bouret, J.-C.
A1  - Lanz, T.
A1  - Hillier, D. J.
A1  - Foellmi, C.
T1  - Clumping in O-type Supergiants
N2  - We have analyzed the spectra of seven Galactic O4 supergiants, with the NLTE wind code CMFGEN. For all stars, we have found that clumped wind models match well lines from different species spanning a wavelength range from FUV to optical, and remain consistent with Hα data. We have achieved an excellent match of the P V λλ1118, 1128 resonance doublet and N IV λ1718, as well as He II λ4686 suggesting that our physical description of clumping is adequate. We find very small volume filling factors and that clumping starts deep in the wind, near the sonic point. The most crucial consequence of our analysis is that the mass loss rates of O stars need to be revised downward significantly, by a factor of 3 and more compared to those obtained from smooth-wind models.
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17662
ER  - 
TY  - CHAP
A1  - Gull, T. R.
T1  - Eta Carinae viewed from different vantages
N2  - The spatially-resolved winds of the massive binary, Eta Carinae, extend an arcsecond on the sky, well beyond the 10 to 20 milliarcsecond binary orbital dimension. Stellar wind line profiles, observed at very different angular resolutions of VLTI/AMBER, HST/STIS and VLT/UVES, provide spatial information on the extended wind interaction structure as it changes with orbital phase. These same wind lines, observable in the starlight scattered off the foreground lobe of the dusty Homunculus, provide time-variant line profiles viewed from significantly different angles. Comparisons of direct and scattered wind profiles observed in the same epoch and at different orbital phases provide insight on the extended wind structure and promise the potential for three-dimensional imaging of the outer wind structures. Massive, long-lasting clumps, including the nebularWeigelt blobs, originated during the two historical ejection events. Wind interactions with these clumps are quite noticeable in spatially-resolved spectroscopy. As the 2009.0 minimum approaches, analysis of existing spectra and 3-D modeling are providing bases for key observations to gain further understanding of this complex massive binary.
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-18200
ER  - 
TY  - CHAP
A1  - Reimer, A.
T1  - Clumping effects on non-thermal particle spectra in massive star systems
N2  - Observational evidence exists that winds of massive stars are clumped. Many massive star systems are known as non-thermal particle production sites, as indicated by their synchrotron emission in the radio band. As a consequence they are also considered as candidate sites for non-thermal high-energy photon production up to gamma-ray energies. The present work considers the effects of wind clumpiness expected on the emitting relativistic particle spectrum in colliding wind systems, built up from the pool of thermal wind particles through diffusive particle acceleration, and taking into account inverse Compton and synchrotron losses. In comparison to a homogeneous wind, a clumpy wind causes flux variations of the emitting particle spectrum when the clump enters the wind collision region. It is found that the spectral features associated with this variability moves temporally from low to high energy bands with the time shift between any two spectral bands being dependent on clump size, filling factor, and the energy-dependence of particle energy gains and losses.
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-18246
ER  - 
TY  - CHAP
A1  - Schnurr, O.
A1  - Crowther, P. A.
T1  - Mid-IR observations of WC stars, and the connection to wind clumping
N2  - We present preliminary results of a tailored atmosphere analysis of six Galactic WC stars using UV, optical, and mid-infrared Spitzer IRS data. With these data, we are able to sample regions from 10 to 10³ stellar radii, thus to determine wind clumping in different parts of the wind. Ultimately, derived wind parameters will be used to accuratelymeasure neon abundances, and to so test predicted nuclear-reaction rates.
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17884
ER  - 
TY  - CHAP
A1  - Vink, J. S.
A1  - Benaglia, P.
A1  - Davies, B.
A1  - de Koter, A.
A1  - Oudmaijer, R. D.
T1  - Advances in mass-loss predictions
N2  - We present the results of Monte Carlo mass-loss predictions for massive stars covering a wide range of stellar parameters. We critically test our predictions against a range of observed massloss rates – in light of the recent discussions on wind clumping. We also present a model to compute the clumping-induced polarimetric variability of hot stars and we compare this with observations of Luminous Blue Variables, for which polarimetric variability is larger than for O and Wolf-Rayet stars. Luminous Blue Variables comprise an ideal testbed for studies of wind clumping and wind geometry, as well as for wind strength calculations, and we propose they may be direct supernova progenitors.
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17948
ER  - 
TY  - CHAP
A1  - Moffat, Anthony F. J.
A1  - Hillier, D. J.
A1  - Hamann, Wolf-Rainer
A1  - Owocki, S. P.
T1  - General Discussion
N2  - Clumping in hot-star winds : proceedings of an international workshop held in Potsdam, Germany, 18. - 22. June 2007
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17953
ER  - 
TY  - CHAP
A1  - Sonneborn, G.
T1  - Imaging and spectroscopy with the James Webb Space Telescope
N2  - The James Webb Space Telescope (JWST) is a large, infrared-optimized space telescope scheduled for launch in 2013. JWST will find the first stars and galaxies that formed in the early universe, connecting the Big Bang to our own Milky Way galaxy. JWST will peer through dusty clouds to see stars forming planetary systems, connecting the MilkyWay to our own Solar System. JWST’s instruments are designed to work primarily in the infrared range of 1 - 28 μm, with some capability in the visible range. JWST will have a large mirror, 6.5 m in diameter, and will be diffraction-limited at 2 μm (0.1 arcsec resolution). JWST will be placed in an L2 orbit about 1.5 million km from the Earth. The instruments will provide imaging, coronography, and multi-object and integral-field spectroscopy across the 1 - 28 μm wavelength range. The breakthrough capabilities of JWST will enable new studies of massive star winds from the Milky Way to the early universe.
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17983
ER  - 
TY  - CHAP
A1  - Owocki, S. P.
T1  - Dynamical simulation of the “velocity-porosity” reduction in observed strength of stellar wind lines
N2  - I use dynamical simulations of the line-driven instability to examine the potential role of the resulting flow structure in reducing the observed strength of wind absorption lines. Instead of the porosity length formalism used to model effects on continuum absorption, I suggest reductions in line strength can be better characterized in terms of a velocity clumping factor that is insensitive to spatial scales. Examples of dynamic spectra computed directly from instability simulations do exhibit a net reduction in absorption, but only at a modest 10-20% level that is well short of the ca. factor 10 required by recent analyses of PV lines.
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17992
ER  - 
TY  - CHAP
A1  - Blomme, R.
T1  - Corotating Interaction Regions and clumping
N2  - We present hydrodynamical models for Corotating Interaction Regions, which were used by Lobel (2007) to model the Discrete Absorption Components in HD 64760. We also discuss our failure to model the rotational modulations seen in the same star.
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-18100
ER  - 
TY  - CHAP
A1  - Kholtygin, A. F.
T1  - Wavelets for looking for clumping in the wind of OB stars
N2  - Clumping in hot-star winds : proceedings of an international workshop held in Potsdam, Germany, 18. - 22. June 2007
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17796
ER  - 
TY  - CHAP
A1  - Urbaneja, M. A.
A1  - Kudritzki, R.-P.
A1  - Puls, Joachim
T1  - Clumping in the winds of O-type CSPNs
N2  - Recent studies of massive O-type stars present clear evidences of inhomogeneous and clumped winds. O-type (H-rich) central stars of planetary nebulae (CSPNs) are in some ways the low mass–low luminosity analogous of those massive stars. In this contribution, we present preliminary results of our on-going multi-wavelength (FUV, UV and optical) study of the winds of Galactic CSPNs. Particular emphasis will be given to the clumping factors derived by means of optical lines (Hα and Heii 4686) and “classic” FUV (and UV) lines.
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17801
ER  - 
TY  - CHAP
A1  - de Koter, A.
A1  - Vink, J. S.
A1  - Muijres, L.
T1  - Constraints on wind clumping from the empirical mass-loss vs. metallicity relation for early-type stars
N2  - We present the latest results on the observational dependence of the mass-loss rate in stellar winds of O and early-B stars on the metal content of their atmospheres, and compare these with predictions. Absolute empirical rates for the mass loss of stars brighter than 10$^{5.2} L_{\odot}$, based on H$\alpha$ and ultraviolet (UV) wind lines, are found to be about a factor of two higher than predictions. If this difference is attributed to inhomogeneities in the wind this would imply that luminous O and early-B stars have clumping factors in their H$\alpha$ and UV line forming regime of about a factor of 3--5. The investigated stars cover a metallicity range $Z$ from 0.2 to 1 $Z_{\odot}$. We find a hint towards smaller clumping factors for lower $Z$. The derived clumping factors, however, presuppose that clumping does not impact the predictions of the mass-loss rate. We discuss this assumption and explain how we intend to investigate its validity in more detail.
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17736
ER  - 
TY  - CHAP
A1  - Reyes-Iturbide, J.
A1  - Velázquez, P.
A1  - Rosado, M.
T1  - 3D numerical model for an asymmetrical superbubble
N2  - Massive stars usually form groups such as OB associations. Their fast stellar winds sweep up collectively the surrounding insterstellar medium (ISM) to generate superbubbles. Observations suggest that superbubble evolution on the surrounding ISM can be very irregular. Numerical simulations considering these conditions could help to understand the evolution of these superbubbles and to clarify the dynamics of these objects as well as the difference between observed X-ray luminosities and the predicted ones by the standard model (Weaver et al. 1977).
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17724
ER  - 
TY  - CHAP
A1  - Groh, J. H.
A1  - Hillier, D. J.
A1  - Damineli, A.
T1  - Mass-loss rate and clumping in LBV stars : the impact of time-dependent effects
N2  - This paper outlines a newly-developed method to include the effects of time variability in the radiative transfer code CMFGEN. It is shown that the flow timescale is often large compared to the variability timescale of LBVs. Thus, time-dependent effects significantly change the velocity law and density structure of the wind, affecting the derivation of the mass-loss rate, volume filling factor, wind terminal velocity, and luminosity. The results of this work are directly applicable to all active LBVs in the Galaxy and in the LMC, such as AG Car, HR Car, S Dor and R 127, and could result in a revision of stellar and wind parameters. The massloss rate evolution of AG Car during the last 20 years is presented, highlighting the need for time-dependent models to correctly interpret the evolution of LBVs.
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17773
ER  - 
TY  - CHAP
ED  - Kurths, Jürgen
ED  - Fradkov, Alexander
ED  - Chen, Guanrong
T1  - The 3rd international IEEE scientific conference on physics and control (PhysCon 2007) : September 3rd-7th 2007 at the University of Potsdam
N2  - During the last few years there was a tremendous growth of scientific activities in the fields related to both Physics and Control theory: nonlinear dynamics, micro- and nanotechnologies, self-organization and complexity, etc. New horizons were opened and new exciting applications emerged. Experts with different backgrounds starting to work together need more opportunities for information exchange to improve mutual understanding and cooperation. The Conference "Physics and Control 2007" is the third international conference focusing on the borderland between Physics and Control with emphasis on both theory and applications. With its 2007 address at Potsdam, Germany, the conference is located for the first time outside of Russia. The major goal of the Conference is to bring together researchers from different scientific communities and to gain some general and unified perspectives in the studies of controlled systems in physics, engineering, chemistry, biology and other natural sciences. We hope that the Conference helps experts in control theory to get acquainted with new interesting problems, and helps experts in physics and related fields to know more about ideas and tools from the modern control theory.
KW  - nonlinear dynamics
KW  - micro- and nanotechnologies
KW  - self-organization
KW  - complexity
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-15228
PB  - Universitätsverlag Potsdam
CY  - Potsdam
ER  - 
TY  - CHAP
A1  - Puls, Joachim
T1  - Discussion : X-rays
N2  - Clumping in hot-star winds : proceedings of an international workshop held in Potsdam, Germany, 18. - 22. June 2007
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-18000
ER  - 
TY  - CHAP
A1  - Szeifert, T.
T1  - Wind variabilities and asymmetries in Luminous Blue Variables
N2  - Luminous Blue Variables show strong changes in their stellar wind on time scales of typically years to decades when they expand and contract radially at approximately constant luminosity. Micro-variability on shorter time scales and amplitudes can be observed superimposed to the larger scale radial changes. I will show long-term time series of high resolution spectra which we have collected in the past 20 years for many of the well known LBVs together with a few time series of weekly sampling (HR Car, R40, R71, R110, R127, S Dor) covering a time windows of up to a few months. Wind variability is seen on short and intermediate time scales with the line profiles changing from P Cygni to inverse P Cygni and double peeked profiles sometimes for the same star and spectral line. On longer time scales the ionisation levels for all chemical elements change drastically due to the strong change of the temperature on the stellar surface. While on the long term the characteristic radial changes may have impact on the over all mass loss rates, the variabilities and asymmetries on short and intermediate time scales may cause false estimates of the mass loss rates when confronting models with the observed line profiles
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-18146
ER  - 
TY  - CHAP
A1  - Moffat, Anthony F. J.
T1  - Observational overview of clumping in hot stellar winds
N2  - In the old days (pre ∼1990) hot stellar winds were assumed to be smooth, which made life fairly easy and bothered no one. Then after suspicious behaviour had been revealed, e.g. stochastic temporal variability in broadband polarimetry of single hot stars, it took the emerging CCD technology developed in the preceding decades (∼1970-80’s) to reveal that these winds were far from smooth. It was mainly high-S/N, time-dependent spectroscopy of strong optical recombination emission lines in WR, and also a few OB and other stars with strong hot winds, that indicated all hot stellar winds likely to be pervaded by thousands of multiscale (compressible supersonic turbulent?) structures, whose driver is probably some kind of radiative instability. Quantitative estimates of clumping-independent mass-loss rates came from various fronts, mainly dependent directly on density (e.g. electron-scattering wings of emission lines, UV spectroscopy of weak resonance lines, and binary-star properties including orbital-period changes, electron-scattering, and X-ray fluxes from colliding winds) rather than the more common, easier-to-obtain but clumping-dependent density-squared diagnostics (e.g. free-free emission in the IR/radio and recombination lines, of which the favourite has always been Hα). Many big questions still remain, such as: What do the clumps really look like? Do clumping properties change as one recedes from the mother star? Is clumping universal? Does the relative clumping correction depend on $\dot{M}$ itself?
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17633
ER  - 
TY  - CHAP
A1  - Puls, Joachim
A1  - Markova, N.
A1  - Najarro, F.
A1  - Hanson, M. M.
T1  - Clumping in O-star winds
N2  - We review various diagnostics of clumping in O-star winds, with special emphasis on its radial stratification. Implications and problems are discussed, and promising NIR methods are presented.
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17683
ER  - 
TY  - CHAP
A1  - St-Louis, N.
A1  - Moffat, Anthony F. J.
T1  - Do clumping corrections increase with decreasing mass-loss rates?
N2  - We report on new mass-loss rate estimates for O stars in six massive binaries using the amplitude of orbital-phase dependent, linear-polarimetric variability caused by electron scattering off free electrons in the winds. Our estimated mass-loss rates for luminous O stars are independent of clumping. They suggest similar clumping corrections as for WR stars and do not support the recently proposed reduction in mass-loss rates of O stars by one or two orders of magnitude.
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17696
ER  - 
TY  - CHAP
A1  - Smith, Nathan
T1  - Independent signs of lower mass-loss rates for O-type stars
N2  - I discuss observational evidence – independent of the direct spectral diagnostics of stellar winds themselves – suggesting that mass-loss rates for O stars need to be revised downward by roughly a factor of three or more, in line with recent observed mass-loss rates for clumped winds. These independent constraints include the large observed mass-loss rates in LBV eruptions, the large masses of evolved massive stars like LBVs and WNH stars, WR stars in lower metallicity environments, observed rotation rates of massive stars at different metallicity, supernovae that seem to defy expectations of high mass-loss rates in stellar evolution, and other clues. I pay particular attention to the role of feedback that would result from higher mass-loss rates, driving the star to the Eddington limit too soon, and therefore making higher rates appear highly implausible. Some of these arguments by themselves may have more than one interpretation, but together they paint a consistent picture that steady line-driven winds of O-type stars have lower mass-loss rates and are significantly clumped.
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17659
ER  - 
TY  - CHAP
A1  - Votruba, V.
A1  - Feldmeier, Achim
A1  - Kubát, Jiří
A1  - Rätzel, D.
T1  - Multicomponent stellar wind of hot stars
N2  - We developed a time-dependent multicomponent hydrodynamical code for simulation of the stellar wind from hot stars and applied it to stars with high and low density winds.
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17677
ER  - 
TY  - CHAP
A1  - Lobel, A.
T1  - Modeling DACs in UV lines of massive hot stars
N2  - We apply the 3-dimensional radiative transport codeWind3D to 3D hydrodynamic models of Corotating Interaction Regions to fit the detailed variability of Discrete Absorption Components observed in Si iv UV resonance lines of HD 64760 (B0.5 Ib). We discuss important effects of the hydrodynamic input parameters on these large-scale equatorial wind structures that determine the detailed morphology of the DACs computed with 3D transfer. The best fit model reveals that the CIR in HD 64760 is produced by a source at the base of the wind that lags behind the stellar surface rotation. The non-corotating coherent wind structure is an extended density wave produced by a local increase of only 0.6% in the smooth symmetric wind mass-loss rate.
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17856
ER  - 
TY  - CHAP
A1  - Prinja, R. K.
A1  - Hodges, S. E.
A1  - Massa, D. L.
A1  - Fullerton, A. W.
A1  - Burnley, A. W.
T1  - Structure in the fast wind of NGC6543
N2  - We exploit time-series $FUSE$ spectroscopy to {\it uniquely} probe spatial structure and clumping in the fast wind of the central star of the H-rich planetary nebula NGC~6543 (HD~164963). Episodic and recurrent optical depth enhancements are discovered in the P{\sc v} absorption troughs, with some evidence for a $\sim$ 0.17-day modulation time-scale. The characteristics of these features are essentially identical to the discrete absorption components' (DACs) commonly seen in the UV lines of massive OB stars, suggesting the temporal structures seen in NGC~6543 likely have a physical origin that is similar to that operating in massive, luminous stars. The mechanism for forming coherent perturbations in the outflows is therefore apparently operating equally in the radiation-pressure-driven winds of widely differing momenta ($\mdot$$v_\infty$$R_\star^{0.5}$) and flow times, as represented by OB stars and CSPN.
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17788
ER  - 
TY  - CHAP
A1  - Marchenko, S. V.
T1  - Wind inhomogeneities in low-Z environment : observations
N2  - We discuss the results of time-resolved spectroscopy of three presumably single Population I Wolf-Rayet stars in the Small Magellanic Cloud, where the ambient metallicity is $\sim 1/5 Z_\odot$. We were able to detect and follow numerous small-scale wind-embedded inhomogeneities in all observed stars. The general properties of the moving features, such as their velocity dispersions, emissivities and average accelerations, closely match the corresponding characteristics of small-scale inhomogeneities in the winds of Galactic Wolf-Rayet stars.
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17769
ER  - 
TY  - CHAP
A1  - Najarro, F.
A1  - Puls, Joachim
A1  - Herrero, A.
A1  - Hanson, M. M.
A1  - Martín-Pintado, J.
A1  - Hillier, D. J.
T1  - Tracking the Clumping in OB Stars from UV to radio
N2  - We review different line and continua diagnostics from the UV to radio, which can be utilized to simultaneously constrain the clumping structure throughout the stellar wind of massive OB stars.
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17701
ER  - 
TY  - CHAP
A1  - Massa, D. L.
T1  - Discussion: Spectroscopy and Mass-Loss Diagnostics
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17821
ER  - 
TY  - CHAP
A1  - Liermann, A.
A1  - Hamann, Wolf-Rainer
T1  - Clumping in Galactic WN stars : a comparison of mass loss rates from UV/optical & radio diagnostics
N2  - The mass loss rates and other parameters for a large sample of Galactic WN stars have been revised by Hamann et al. (2006), using the most up-to date Potsdam Wolf-Rayet (PoWR) model atmospheres. For a sub-sample of these stars exist measurements of their radio free-free emission. After harmonizing the adopted distance and terminal wind velocities, we compare the mass loss rates obtained from the two diagnostics. The differences are discussed as a possible consequence of different clumping contrast in the line-forming and radio-emitting regions.
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17816
ER  - 
TY  - CHAP
A1  - Raassen, A. J. J.
A1  - Hucht, K. A. van der
A1  - Miller, N. A.
A1  - Cassinelli, Joseph P.
T1  - XMM-Newton observations of zeta Orionis (O9.7 Ib) : a collisional ionization equilibrium model
N2  - We present the analysis of XMM-Newton observations of ζ Orionis. The analysis is based on fitting to the total spectrum as well as diagnostics of individual line.
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17747
ER  - 
TY  - CHAP
A1  - Ignace, R.
A1  - Gayley, K. G.
T1  - Circumstellar Magnetic Field Diagnostics from Line Polarization
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-18066
ER  - 
TY  - CHAP
A1  - Walter, R.
A1  - Zurita-Heras, J.
A1  - Leyder, J.-C.
T1  - Probing clumpy stellar winds with a neutron star
N2  - INTEGRAL tripled the number of super-giant high-mass X-ray binaries (sgHMXB) known in the Galaxy by revealing absorbed and fast transient (SFXT) systems. Quantitative constraints on the wind clumping of massive stars can be obtained from the study of the hard X-ray variability of SFXT. A large fraction of the hard X-ray emission is emitted in the form of flares with a typical duration of 3 ksec, frequency of 7 days and luminosity of $10^{36}$ erg/s. Such flares are most probably emitted by the interaction of a compact object orbiting at $\sim10~R_*$ with wind clumps ($10^{22 ... 23}$ g) representing a large fraction of the stellar mass-loss rate. The density ratio between the clumps and the inter-clump medium is $10^{2 ... 4}$. The parameters of the clumps and of the inter-clump medium, derived from the SFXT flaring behavior, are in good agreement with macro-clumping scenario and line-driven instability simulations. SFXT are likely to have larger orbital radius than classical sgHMXB.
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-18024
ER  - 
TY  - CHAP
A1  - Cassinelli, Joseph P.
A1  - Ignace, R.
A1  - Waldron, W.
A1  - Cho, J.
A1  - Murphy, N.
A1  - Lazarian, A.
T1  - X-ray line emission produced in clump bow shocks
N2  - We summarize Chandra observations of the emission line profiles from 17 OB stars. The lines tend to be broad and unshifted. The forbidden/intercombination line ratios arising from Helium-like ions provide radial distance information for the X-ray emission sources, while the H-like to He-like line ratios provide X-ray temperatures, and thus also source temperature versus radius distributions. OB stars usually show power law differential emission measure distributions versus temperature. In models of bow shocks, we find a power law differential emission measure, a wide range of ion stages, and the bow shock flow around the clumps provides transverse velocities comparable to HWHM values. We find that the bow shock results for the line profile properties, consistent with the observations of X-ray line emission for a broad range of OB star properties.
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-18057
ER  - 
TY  - CHAP
A1  - Runacres, M. C.
T1  - Hydrodynamical models of clumping beyond 50 R∗
N2  - We present one-dimensional, time-dependent models of the clumps generated by the linedeshadowing instability. In order to follow the clumps out to distances of more than 1000 R∗, we use an efficient moving-box technique. We show that, within the approximations, the wind can remain clumped well into the formation region of the radio continuum.
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-18030
ER  - 
TY  - CHAP
A1  - Schnerr, R. S.
A1  - Henrichs, H. F.
T1  - Magnetic fields and wind variability in massive stars
N2  - This paper describes the thesis work of Schnerr (2007) entitled ”Magnetic fields and mass loss in massive stars“, which aimed at a better understanding of the impact of magnetic fields on the winds of massive stars.
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-18075
ER  - 
TY  - CHAP
A1  - Leutenegger, M. A.
A1  - Cohen, David H.
A1  - Kahn, S. M.
A1  - Owocki, S. P.
A1  - Paerels, F. B. S.
T1  - Resonance scattering in the X-ray emission lines profiles of ζ Puppis
N2  - We present XMM-Newton Reflection Grating Spectrometer observations of pairs of X-ray emission line profiles from the O star ζ Pup that originate from the same He-like ion. The two profiles in each pair have different shapes and cannot both be consistently fit by models assuming the same wind parameters. We show that the differences in profile shape can be accounted for in a model including the effects of resonance scattering, which affects the resonance line in the pair but not the intercombination line. This implies that resonance scattering is also important in single resonance lines, where its effect is difficult to distinguish from a low effective continuum optical depth in the wind. Thus, resonance scattering may help reconcile X-ray line profile shapes with literature mass-loss rates.
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-18085
ER  - 
TY  - CHAP
A1  - Massa, D. L.
A1  - Prinja, R. K.
A1  - Fullerton, A. W.
T1  - The effects of clumping on wind line variability
N2  - We review the effects of clumping on the profiles of resonance doublets. By allowing the ratio of the doublet oscillator strenghts to be a free parameter, we demonstrate that doublet profiles contain more information than is normally utilized. In clumped (or porous) winds, this ratio can lies between unity and the ratio of the f-values, and can change as a function of velocity and time, depending on the fraction of the stellar disk that is covered by material moving at a particular velocity at a given moment. Using these insights, we present the results of SEI modeling of a sample of B supergiants, ζ Pup and a time series for a star whose terminal velocity is low enough to make the components of its Si VIλλ1400 independent. These results are interpreted within the framewrok of the Oskinova et al. (2007) model, and demonstrate how the doublet profiles can be used to extract infromation about wind structure.
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-18095
ER  - 
TY  - CHAP
A1  - Vink, J. S.
T1  - Discussion: Hydrodynamic modeling
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-18046
ER  - 
TY  - CHAP
A1  - Hillier, D. J.
T1  - On the influence of clumping on O and Wolf-Rayet spectra
N2  - Overwhelming observational and theoretical evidence suggests that the winds of massive stars are highly clumped. We briefly discuss the influence of clumping on model diagnostics and the difficulties of allowing for the influence of clumping on model spectra. Because of its simplicity, and because of computational ease, most spectroscopic analyses incorporate clumping using the volume filling factor. The biases introduced by this approach are uncertain. To investigate alternative clumping models, and to help determine the validity of parameters derived using the volume filling factor method, we discuss results derived using an alternative model in which we assume that the wind is composed of optically thick shells.
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17903
ER  - 
TY  - CHAP
A1  - Fullerton, A. W.
T1  - Discussion: Spectral modeling
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17917
ER  - 
TY  - CHAP
A1  - Townsend, R. H. D.
T1  - Techniques for simulating radiative transfer through porous media
N2  - In this contribution, I discuss some basic techniques that can be used to simulate radiative transfer through porous media. As specific examples, I consider scattering transfer through a clumped slab, and X-ray emission line formation in a clumped wind.
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17866
ER  - 
TY  - CHAP
A1  - ud-Doula, A.
T1  - Large-scale wind structure due to magnetic fields
N2  - Magnetic fields influence the dynamics of hot-star winds and create large scale structure. Based on numerical magnetohydrodynamic (MHD) simulations, we model the wind of θ¹ Ori C, and then use the SEI method to compute synthetic line profiles for a range of viewing angles as function of rotational phase. The resulting dynamic spectrum for a moderately strong line shows a distinct modulation, but with a phase that seems at odds with available observations.
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-18010
ER  - 
TY  - CHAP
A1  - Iping, R.C.
A1  - Sonneborn, G.
A1  - Massa, D.L.
A1  - Gies, D.
A1  - Williams, Simon E.
T1  - Far-ultraviolet spectroscopy of O+O binaries in the Magellanic Clouds
N2  - We report FUSE observations in 2005–2006 of three O-type, double-lined spectroscopic binaries in the Magellanic Clouds. The systems have very short periods (1.4–2.25 d), represent rare, young evolutionary stages of massive stars and binaries, and provide a unique glimpse at some of the most massive systems that form in dense clusters of massive stars. Improved orbit parameters, including revised masses, for LH54-425 are derived from new ctio spectroscopy. The systems are: LH54-425 in the LMC (O3V + O5V, P=2.25d, 62+37M⊙), J053441-693139 in the LMC (O2-3If+O6V, P=1.4 d, 41+27M⊙), and Hodge 53-47 in the SMC (O6V + O4-5IIIf, P=2.2 d, 24+14M⊙, where the O4 star appears to be less massive than the O6 star). Their short periods indicates that wind interaction and mass transfer are likely important factors in their evolution. The spectra provide quantitative and systematic studies of phase-dependent stellar wind properties, wind collision effects in O+O binaries at lower metallicities, improved radial velocity curves, and FUV spectro-photometric changes as a function of orbital phase.
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17896
ER  - 
TY  - CHAP
A1  - Kusterer, D.-J.
A1  - Nagel, T.
A1  - Werner, K.
A1  - Feldmeier, Achim
T1  - Radiative transfer in CV disk winds
N2  - Mass accretion onto compact objects through accretion disks is a common phenomenon in the universe. It is seen in all energy domains from active galactic nuclei through cataclysmic variables (CVs) to young stellar objects. Because CVs are fairly easy to observe, they provide an ideal opportunity to study accretion disks in great detail and thus help us to understand accretion also in other energy ranges. Mass accretion in these objects is often accompanied by mass outflow from the disks. This accretion disk wind, at least in CVs, is thought to be radiatively driven, similar to O star winds. WOMPAT, a 3-D Monte Carlo radiative transfer code for accretion disk winds of CVs is presented.
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17847
ER  - 
TY  - CHAP
A1  - Davies, B.
A1  - Vink, J. S.
A1  - Oudmaijer, R. D.
T1  - Modelling the polarimetric variability of hot stars
N2  - Many hot stars exhibit stochastic polarimetric variability, thought to arise from clumping low in the wind. Here we investigate the wind properties required to reproduce this variability using analytic models, with particular emphasis on Luminous Blue Variables. We find that the winds must be highly structured, consisting of a large number of optically-thin clumps; while we find that the overall level of polarization should scale with mass-loss rate – consistent with observations of LBVs. The models also predict variability on very short timescales, which is supported by the results of a recent polarimetric monitoring campaign.
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17939
ER  - 
TY  - CHAP
A1  - Kubát, Jiří
A1  - Saad, S. M.
T1  - Moving absorption bumps in the spectra of Be stars
N2  - Several Be binaries exhibit an absorption bump moving across the blue wing of hydrogen emission lines towards the line center. This bump is demonstrated for the case of two bright Be stars, κ Dra and 4 Her. It is not clear what is the reason for this travelling bump.
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17879
ER  - 
TY  - CHAP
A1  - Nielsen, K. E.
T1  - On irregular line profiles in the optical spectrum of Eta Carinae
N2  - The optical spectrum of Eta Carinae (η Car) is prominent in H I, He i and Fe ii wind lines, all of which vary both in absorption and emission with phase. The phase dependance is a consequence of the interaction between the two objects in the η Car binary (η Car A & B). The binary system is enshrouded by ejecta from previous mass ejection events and consequently, η Car B is not directly observable. We have traced the He i lines over η Car’s spectroscopic period, using HST/STIS data obtained with medium spectral, but high angular, resolving power, and created a radial velocity curve for the system. The He I lines are formed in the core of the system, and appear to be a composite of multiple features formed in spatially separated regions. The sources of their irregular line profiles are still not fully understood, but can be attributed to emission/absorption near the wind-wind interface and/or a direct consequence of the η Car A’s, massive, clumpy wind. This paper will discuss the spectral variability, the narrow emission structure of the He i lines and how clumpiness of the winds may impede the construction of the reliable radial velocity curve, necessary for characterizations of especially η Car B.
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-18227
ER  - 
TY  - CHAP
A1  - Cohen, David H.
A1  - Leutenegger, M. A.
A1  - Townsend, R. H. D.
T1  - Quantitative analysis of resolved X-ray emission line profiles of O stars
N2  - By quantitatively fitting simple emission line profile models that include both atomic opacity and porosity to the Chandra X-ray spectrum of ζ Pup, we are able to explore the trade-offs between reduced mass-loss rates and wind porosity. We find that reducing the mass-loss rate of ζ Pup by roughly a factor of four, to 1.5 × 10−6 M⊙ yr−1, enables simple non-porous wind models to provide good fits to the data. If, on the other hand, we take the literature mass-loss rate of 6×10−6 M⊙ yr−1, then to produce X-ray line profiles that fit the data, extreme porosity lengths – of h∞ ≈ 3 R∗ – are required. Moreover, these porous models do not provide better fits to the data than the non-porous, low optical depth models. Additionally, such huge porosity lengths do not seem realistic in light of 2-D numerical simulations of the wind instability.
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-18115
ER  - 
TY  - CHAP
A1  - Morrison, N. D.
A1  - Rother, R.
A1  - Kurschat, N.
T1  - Hα line profile variability in the B8Ia-type supergiant Rigel (β Ori)
N2  - Hα observations of Rigel obtained on 184 nights during the past ten years with the 1-m telescope and ´echelle spectrograph of Ritter Observatory are surveyed. The line profiles were classified in terms of morphology. About 1/4 of them are of P Cygni type, about 15% inverse P Cygni, about 25% double-peaked, about 1/3 pure absorption, and a few are single emission lines. Transformation of the profile from one type to another typically takes a few days. Although the line stays in absorption for extended intervals, only one high-velocity absorption event of the intensity reported by Kaufer et al. (1996a) was observed, in late 2006. Late in this event, Hα absorption occurred farther to the red than the red wing of a plausible photospheric absorption component, an indication of infalling material. In general, as the absorption events come to an end, the emission typically returns with an inverse P Cygni profile. The Hα profile class shows no obvious correlation with the radial velocity of C II λ6578, a photospheric absorption line.
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-18120
ER  - 
TY  - CHAP
A1  - Chené, A.-N.
A1  - Moffat, Anthony F. J.
A1  - Crowther, P. A.
T1  - Rapidly accelerating clumps in the winds of the very hot WNE Stars
N2  - We study the time variability of emission lines in three WNE stars : WR 2 (WN2), WR 3 (WN3ha) and WR152 (WN3). While WR 2 shows no variability above the noise level, the other stars do show variation, which are like other WR stars in WR 152 but very fast in WR 3. From these motions, we deduce a value of β ∼1 for WR 3 that is like that seen in O stars and β ∼2–3 for WR 152, that is intermediate between other WR stars and WR 3.
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-18163
ER  - 
TY  - CHAP
A1  - Kholtygin, A. F.
T1  - Modelling the induced clumping stochastic line profile variability
N2  - We model the line profile variability (lpv) in spectra of clumped stellar atmospheres using the Stochastic Clump Model (SCM) of the winds of early-type stars. In this model the formation of dense inhomogeneities (clumps) in the line driven winds is considered as being a stochastic process. It is supposed that the emission due to clumps mainly contributes to the intensities of emission lines in the stellar spectra. It is shown that in the framework of the SCM it is possible to reproduce both the mean line profiles and a common pattern of the lpv.
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-18180
ER  - 
TY  - CHAP
A1  - Cassinelli, Joseph P.
T1  - Discussion: Magnetic fields, variability
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-18195
ER  - 
TY  - CHAP
A1  - St-Louis, N.
T1  - Discussion: Binaries, colliding winds, LBVs and high energy radiation
N2  - Clumping in hot-star winds : proceedings of an international workshop held in Potsdam, Germany, 18. - 22. June 2007
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-18155
ER  - 
TY  - CHAP
A1  - Romero, G. E.
A1  - Owocki, S. P.
A1  - Araudo, A. T.
A1  - Townsend, R. H. D.
A1  - Benaglia, P.
T1  - Using gamma-rays to probe the clumped structure of stellar winds
N2  - Gamma-rays can be produced by the interaction of a relativistic jet and the matter of the stellar wind in the subclass of massive X-ray binaries known as “microquasars”. The relativistic jet is ejected from the surroundings of the compact object and interacts with cold protons from the stellar wind, producing pions that then quickly decay into gamma-rays. Since the resulting gamma-ray emissivity depends on the target density, the detection of rapid variability in microquasars with GLAST and the new generation of Cherenkov imaging arrays could be used to probe the clumped structure of the stellar wind. In particular, we show here that the relative fluctuation in gamma rays may scale with the square root of the ratio of porosity length to binary separation, $\sqrt{h/a}$, implying for example a ca. 10% variation in gamma ray emission for a quite moderate porosity, h/a ∼ 0.01.
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-18210
ER  - 
TY  - CHAP
A1  - Weis, K.
T1  - Wind relics : clumps, inhomogeneities and outflows in LBV nebulae
N2  - The most massive stars are those with the shortest but most active life. One group of massive stars, the Luminous Blue Variables (LBVs), of which only a few objects are known, are in particular of interest concerning the stability of stars. They have a high mass loss rate and are close to being instable. This is even more likely as rotation becomes an important factor in stellar evolution of these stars. Through massive stellar winds and sometimes giant eruptions, LBV nebulae are formed. Various aspects in the evolution in the LBV phase lead, beside the large scale morphological and kinematical differences, to a diversity of small structures like clumps, rims, and outflows in these nebulae.
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-18235
ER  - 
TY  - CHAP
A1  - Krtička, Jiri
A1  - Puls, Joachim
A1  - Kubát, Jiří
T1  - The influence of clumping on predicted O star wind parameters
N2  - We study the influence of clumping on the predicted wind structure of O-type stars. For this purpose we artificially include clumping into our stationary wind models. When the clumps are assumed to be optically thin, the radiative line force increases compared to corresponding unclumped models, with a similar effect on either the mass-loss rate or the terminal velocity (depending on the onset of clumping). Optically thick clumps, alternatively, might be able to decrease the radiative force.
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17969
ER  - 
TY  - CHAP
A1  - Kraus, M.
A1  - Kubát, Jiří
A1  - Krtička, Jiri
T1  - Wind emission of OB supergiants and the influence of clumping
N2  - The influence of the wind to the total continuum of OB supergiants is discussed. For wind velocity distributions with β > 1.0, the wind can have strong influence to the total continuum emission, even at optical wavelengths. Comparing the continuum emission of clumped and unclumped winds, especially for stars with high β values, delivers flux differences of up to 30% with maximum in the near-IR. Continuum observations at these wavelengths are therefore an ideal tool to discriminate between clumped and unclumped winds of OB supergiants.
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17757
ER  - 
TY  - CHAP
ED  - Hamann, Wolf-Rainer
ED  - Feldmeier, Achim
ED  - Oskinova, Lida
T1  - Clumping in hot-star winds : proceedings of an international workshop held in Potsdam, Germany, 18. - 22. June 2007
N2  - Stellar winds play an important role for the evolution of massive stars and their cosmic environment. Multiple lines of evidence, coming from spectroscopy, polarimetry, variability, stellar ejecta, and hydrodynamic modeling, suggest that stellar winds are non-stationary and inhomogeneous. This is referred to as 'wind clumping'. The urgent need to understand this phenomenon is boosted by its far-reaching implications. Most importantly, all techniques to derive empirical mass-loss rates are more or less corrupted by wind clumping. Consequently, mass-loss rates are extremely uncertain. Within their range of uncertainty, completely different scenarios for the evolution of massive stars are obtained. Settling these questions for Galactic OB, LBV and Wolf-Rayet stars is prerequisite to understanding stellar clusters and galaxies, or predicting the properties of first-generation stars. In order to develop a consistent picture and understanding of clumped stellar winds, an international workshop on 'Clumping in Hot Star Winds' was held in Potsdam, Germany, from 18. - 22. June 2007. About 60 participants, comprising almost all leading experts in the field, gathered for one week of extensive exchange and discussion. The Scientific Organizing Committee (SOC) included John Brown (Glasgow), Joseph Cassinelli (Madison), Paul Crowther (Sheffield), Alex Fullerton (Baltimore), Wolf-Rainer Hamann (Potsdam, chair), Anthony Moffat (Montreal), Stan Owocki (Newark), and Joachim Puls (Munich). These proceedings contain the invited and contributed talks presented at the workshop, and document the extensive discussions.
KW  - Sternwinde
KW  - Massenverlust
KW  - Strahlungstransport
KW  - hydrodynamische Modellierung
KW  - massereiche Sterne
KW  - stellar winds
KW  - mass loss
KW  - radiative transfer
KW  - hydrodynamic modeling
KW  - massive stars
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-13981
SN  - 978-3-940793-33-1
PB  - Universitätsverlag Potsdam
CY  - Potsdam
ER  - 
TY  - CHAP
A1  - Piskorski, Jakub
T1  - ExPRESS : extraction pattern recognition engine and specification suite
N2  - The emergence of information extraction (IE) oriented pattern engines has been observed during the last decade. Most of them exploit heavily finite-state devices. This paper introduces ExPRESS – a new extraction pattern engine, whose rules are regular expressions over flat feature structures. The underlying pattern language is a blend of two previously introduced IE oriented pattern formalisms, namely, JAPE, used in the widely known GATE system, and the unificationbased XTDL formalism used in SProUT. A brief and technical overview of ExPRESS, its pattern language and the pool of its native linguistic components is given. Furthermore, the implementation of the grammar interpreter is addressed too.
Y1  - 2008
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-27227
ER  -