Extern
Refine
Has Fulltext
- yes (440) (remove)
Year of publication
Document Type
- Conference Proceeding (122)
- Doctoral Thesis (96)
- Article (79)
- Postprint (68)
- Working Paper (39)
- Monograph/Edited Volume (14)
- Review (9)
- Preprint (6)
- Master's Thesis (4)
- Habilitation Thesis (2)
Language
- English (440) (remove)
Keywords
- USA (7)
- United States (7)
- Arktis (6)
- moderne jüdische Geschichte (6)
- Arctic (5)
- climate change (5)
- modern Jewish history (5)
- 20. Jahrhundert (4)
- 20th century (4)
- Fernerkundung (4)
- 19. Jahrhundert (3)
- COVID-19 (3)
- Diversity (3)
- Holozän (3)
- Immunoassay (3)
- Klimawandel (3)
- Kohlenstoff (3)
- Nanopartikel (3)
- carbon (3)
- cluster expansion (3)
- gender (3)
- infinite-dimensional Brownian diffusion (3)
- molecular motors (3)
- molekulare Motoren (3)
- remote sensing (3)
- 19th century (2)
- Anden (2)
- Andes (2)
- Antarctica (2)
- Antarktis (2)
- Argentina (2)
- Argentinien (2)
- Atmosphäre (2)
- Datenanalyse (2)
- Energiespeicher (2)
- Fluoreszenz-Resonanz-Energie-Transfer (2)
- Focus (2)
- Galaxien (2)
- Geodynamik (2)
- German history (2)
- Graphentheorie (2)
- Holocene (2)
- ICT (2)
- Informatics (2)
- Kohlenstoffnitriden (2)
- Korrosion (2)
- Lidar (2)
- Magnetismus (2)
- Magnetohydrodynamik (2)
- Modern Jewish history (2)
- N400 (2)
- PUFA (2)
- Rheologie (2)
- Rheology (2)
- Schadensmodellierung (2)
- Seesedimente (2)
- Seismologie (2)
- Spektroskopie (2)
- Systembiologie (2)
- Virus (2)
- air-water interface (2)
- atmosphere (2)
- carbon nitrides (2)
- carbon pricing (2)
- climate policy (2)
- corrosion (2)
- cosmic rays (2)
- deutsche Geschichte (2)
- energy policy (2)
- energy storage (2)
- entrepreneurship (2)
- entropy (2)
- experiment (2)
- fatty acid (2)
- food quality (2)
- galaxies (2)
- gesture (2)
- grammaticalization (2)
- graph theory (2)
- heterogene Photokatalyse (2)
- heterogeneous photocatalysis (2)
- higher education (2)
- immunoassay (2)
- kosmische Strahlung (2)
- machine learning (2)
- magnetohydrodynamics (2)
- mental health (2)
- migration (2)
- nanoparticles (2)
- organic synthesis (2)
- organische Synthese (2)
- primary school (2)
- seismology (2)
- self-employment (2)
- stable isotopes (2)
- stochastic processes (2)
- stochastische Prozesse (2)
- virus (2)
- (implicit) prosody (1)
- 2D Numerical Modelling (1)
- 315 nm (1)
- 46 (3) 2009 (1)
- 473 nm (1)
- 946 nm (1)
- AC Elektrokinetik (1)
- AC Elektroosmosis (1)
- AC electrokinetics (1)
- AC electroosmosis (1)
- ACIDIFICATION (1)
- AGN (1)
- AMNET (1)
- ARMS (1)
- ASPECT (1)
- ATRP (1)
- Active Labor Market Policy (1)
- Adana Basin (1)
- Adana Becken (1)
- Adaptive hypermedia (1)
- Adsorption (1)
- Adverbial Quantification (1)
- Aerosole (1)
- Aerosols (1)
- Africa (1)
- Akan (1)
- Aktiven Galaxienkerne (1)
- Allantoin (1)
- Allgemeine Relativitätstheorie (1)
- Alternative Semantics (1)
- Altiplano (1)
- Aluminiumlegierung (1)
- Alzheimer's Disease (1)
- Anaphylatoxin (1)
- Anatomy (1)
- Animal (1)
- Animal personality (1)
- Anpassung (1)
- Antibiotic alternatives (1)
- Antibiotic resistance (1)
- Antibiotikaersatz (1)
- Antibiotikaresistenz (1)
- Antikörper (1)
- Antwortmengenprogrammierung (1)
- Archetyp (1)
- Arctic aerosol (1)
- Arctic haze (1)
- Arctic tundra (1)
- Arnos Padiri (1)
- Association Rule Mining (1)
- Assoziationsregeln (1)
- Astronomie (1)
- Asynchrone Schaltung (1)
- Asynchronous circuit (1)
- Atmosphärenforschung (1)
- Bachelor (1)
- Backward ownership (1)
- Bakterien (1)
- Basalt-Vulkane (1)
- Bay of Bengal (1)
- Bayesian Network (1)
- Bayesianisches Netzwerk (1)
- Bayesianism (1)
- Bayesianismus (1)
- Bedingte Inklusionsabhängigkeiten (1)
- Bemessungshochwasser (1)
- Beschichtungen (1)
- Beta-Lactoglobulin (1)
- Beweidung (1)
- Bi2Se3 (1)
- Bi2Te3 (1)
- Bildung (1)
- Bindungsinteraktion (1)
- Biochemical analysis (1)
- Biofilm (1)
- Biokonjugate (1)
- Biomoleküle (1)
- Biophotonik (1)
- Bioraffinerie (1)
- Blattverschiebung (1)
- Boden (1)
- Bodenunruhe (1)
- Bruchmodel (1)
- Bryophytes (1)
- Bucht von Bengalen (1)
- Bulge (1)
- CS Ed Research (1)
- CS at school (1)
- CS curriculum (1)
- CSC (1)
- Caco-2 (1)
- Canonical Gibbs measure (1)
- Capsule (1)
- Carbo-Iron (1)
- Carbon Capture (1)
- Carbon Dioxide Removal (1)
- Cars (1)
- Catecholamine (1)
- Causal structure (1)
- Chaco-Paraná Becken (1)
- Chaco-Paraná basin (1)
- Chalkogenide (1)
- Charnockit (1)
- Chemistry of fresh water (1)
- Chemokinematik der Milchstraße (1)
- Chlamydomonas (1)
- Chloroplast transformation (1)
- Chloroplastentransformation (1)
- Citrazinsäure (1)
- Climate Policy (1)
- Climate reconstruction (1)
- Clustering (1)
- Color vision Aging (1)
- Comparing programming environments (1)
- Complement system (1)
- Complex networks (1)
- Computer Science Education (1)
- Conditional Inclusion Dependency (1)
- Confluence (1)
- Constraint Solving (1)
- Continental Rifts (1)
- Controller-Resynthese (1)
- Core-Collapse Supernovae (1)
- Course development (1)
- Course marketing (1)
- Course of Study (1)
- Courses for female students (1)
- Covert Variables (1)
- Covid-19 (1)
- Cu doped InP (1)
- Cu-dotiertes InP (1)
- Curricula Development (1)
- Curriculum analysis (1)
- DAS (1)
- DGVM (1)
- Daphnia (1)
- Data Dependency (1)
- Data-Mining (1)
- Datenabhängigkeiten (1)
- Datenintegration (1)
- Deduction (1)
- Deformation (1)
- Deligne Cohomology (1)
- Deligne Kohomologie (1)
- Demokratisierung (1)
- Density modelling (1)
- Deoxyfructosazin (1)
- Diamantstempelzelle (1)
- Diatomeen (1)
- Diatoms (1)
- Dichtemodellierung (1)
- Dielektrophorese (1)
- Difference-in-Differences (1)
- Diskursverstehen (1)
- Diversität (1)
- Domain Restriction (1)
- Downstep (1)
- Dreissena polymorpha (1)
- Dronning Maud Land (1)
- Durchmusterung (1)
- E-DSGE (1)
- E. coli (1)
- EAAT1 (1)
- EKP (1)
- EROSION (1)
- ERP (1)
- ERPs (1)
- EVENTS (1)
- Earthquake (1)
- East European Jewish history (1)
- Ecology (1)
- Ecotoxicology (1)
- Einkapselung (1)
- Einzelatomkatalyse (1)
- Eisbohrkern (1)
- Electron acceleration (1)
- Elektronenbeschleunigung (1)
- Emissionslinienklassifikation (1)
- Employee Training (1)
- Emulsion (1)
- Energietransfer (1)
- Energy expenditure (1)
- English and Physics teacher trainees (1)
- Entrepreneurship (1)
- Entry deterrence (1)
- Entstehung der Milchstraße (1)
- Erdbeben (1)
- Erdmantel (1)
- Erkennen von Meta-Daten (1)
- Erosion (1)
- Ethics (1)
- Etna (1)
- Europa (1)
- Europe (1)
- European Alps (1)
- European hare (1)
- European history (1)
- Evolution (1)
- Evolution der Milchstraße (1)
- Exoplaneten (1)
- Exoplanetenatmosphären (1)
- Experimental study (1)
- Exploration (1)
- FARIMA (1)
- FastScape (1)
- Ferroperiklas (1)
- Figurative Sprachverarbeitung (1)
- Figurative language processing (1)
- Firm Growth (1)
- Flache Subduktion (1)
- Flat subduction (1)
- Fluorpolymere (1)
- Foreclosure (1)
- Foreland (1)
- Foreland basin (1)
- Foreland basins (1)
- Forstwirtschaft (1)
- Frucht (1)
- Förster Resonanz Energie Transfer (1)
- GC-MS (1)
- GIS (1)
- GITEWS (1)
- GPS (1)
- Galaxie: allgemein (1)
- Galaxienhaufen (1)
- Galicia (1)
- Galizien (1)
- Gasgeochemie (1)
- Geistesgeschichte (1)
- Gen-Koexpression (1)
- Gender (1)
- Gene co-expression (1)
- General Relativity (1)
- General subject “Information” (1)
- Geodynamic Modelling (1)
- Geodynamics (1)
- Geodynamische Modellierung (1)
- Gerben (1)
- Gerbes (1)
- German Jewry (1)
- Geschwindigkeitsmodell (1)
- Gibbs field (1)
- Gibbs measure (1)
- Gletschervorfeld (1)
- Global Differentialgeometry (1)
- Globale Differentialgeometrie (1)
- Glucagon (1)
- Glutamat (1)
- Glutamate (1)
- Grabenbrüche (1)
- Grammatica (1)
- Grandonica (1)
- Gravitational Waves (1)
- Gravitationswellen (1)
- Greenhouse Gas Emissions (1)
- Greenland (1)
- Grenzflächenchemie (1)
- Grenzschicht (1)
- Grundwassersanierung (1)
- Grönland (1)
- Grüne Chemie (1)
- Gyrochronologie (1)
- H/V (1)
- HMA (1)
- HVSR (1)
- HYDROGRAPH SEPARATION (1)
- Hanxleden (1)
- Hauptfaserbündel (1)
- Hebung des Plateaus (1)
- HepG2 (1)
- Hepatic artery (1)
- Hepatic glucose balance (1)
- Hepatic hemodynamics (1)
- Hepatic lactate balance (1)
- Hepatic nerve (1)
- Heptazine (1)
- High growth firms (1)
- Hochdruck (1)
- Hochwasserrisiko (1)
- Holonomie (1)
- Holonomy (1)
- Horace Kallen (1)
- Horizontal flux (1)
- Human Capital Investments (1)
- Hyperakkumulation (1)
- Hysterese (1)
- ICT curriculum (1)
- ISSEP (1)
- Impakt (1)
- Impermanence (1)
- InSAR (1)
- Indian Summer Monsoon (1)
- Indischer Sommermonsun (1)
- Influenza (1)
- Informatics Education (1)
- Informatik (1)
- Informatikdidaktik (1)
- Information Ethics (1)
- Information Processing (1)
- Inlandeis (1)
- Innovation (1)
- Institutions (1)
- Inter-individual differences (1)
- Interacting Diffusion Processes (1)
- Intersectionality (1)
- Intervention Effect (1)
- Intonation (1)
- Introgression (1)
- Inversion (1)
- Ionenmobilitätspektrometrie (1)
- Isaac Leeser (1)
- Isaac Mayer Wise (1)
- Israel (1)
- JH-III-specific carrier protein (1)
- Japanese (1)
- Jets (1)
- Job Creation (1)
- Job Search (1)
- Jurkat cells (1)
- Juvenile hormone (1)
- KINETIC-ENERGY (1)
- Karbonnitrid Ionothermalsynthese (1)
- Kathode (1)
- Kausalstruktur (1)
- Kern-Kollaps-Supernovae (1)
- Kern-Mantel Grenze (1)
- Key Competencies (1)
- Klimadaten (1)
- Klimanetzwerke (1)
- Klimaphysik (1)
- Klimarekonstruktion (1)
- Klimavariabilität (1)
- Kohlenstoffhaushalt (1)
- Kohlenstoffkreislauf (1)
- Kohlenstoffmaterialien (1)
- Kohlenstoffmodell (1)
- Kohnen (1)
- Komplexe Netzwerke (1)
- Kultivierung (1)
- LAEs (1)
- LC/HRMS (1)
- LOC (1)
- LPJ (1)
- Labor Market Mobility (1)
- Lake Constance (1)
- Lake sediments (1)
- Langevin Dynamics (1)
- Lanthanoide (1)
- Laser ablation (1)
- Lateglacial (1)
- Lavafontänen (1)
- Leptinotarsa decemlineata (1)
- Li-Ionen-Akkus (1)
- Li-Ionen-Kondensator (1)
- Li-ion batteries (1)
- Li-ion capacitor (1)
- LiFePO4 (1)
- Lignin (1)
- Link Discovery (1)
- Link-Entdeckung (1)
- Linked Open Data (1)
- Logic Programming (1)
- Logics (1)
- Lokalisierung von Deformation (1)
- Lumineszenz (1)
- Lyman Kontinuum (1)
- Lyman alpha (1)
- Lyman continuum (1)
- Lyman-Alpha-Emitter (1)
- Lyman-alpha emitters (1)
- Lysimeter (1)
- MESOSCALE CONVECTIVE COMPLEXES (1)
- MIXTURE (1)
- MSPAC (1)
- Macular pigment (1)
- Magnetfelder (1)
- Magnetoelastizität (1)
- Malliavin calculus (1)
- Manager Decisions (1)
- Markov chains (1)
- Markov-Prozesse (1)
- Markovketten (1)
- Massenspektrometrie (1)
- Massenverlust (1)
- Mechanobiologie (1)
- Meereis (1)
- Mehrschichtsysteme (1)
- Memory studies (1)
- Mesokristalle (1)
- Mesoporosity (1)
- Mesoporosität (1)
- Metabolism (1)
- Metabolit (1)
- Metabolome (1)
- Metadata Discovery (1)
- Metadatenentdeckung (1)
- Metadatenqualität (1)
- Meteorologie (1)
- Methankreislauf (1)
- MiSpEx (1)
- Microsaccades (1)
- Microsaccadic Inhibition (1)
- Microschwimmer (1)
- Middle East (1)
- Mikrokapsel (1)
- Mikroplatte (1)
- Mikrowellensynthese (1)
- Mikrozonierung (1)
- Milky Way chemo-kinematics (1)
- Milky Way evolution (1)
- Milky Way formation (1)
- Mineralverwitterungsreaktionen (1)
- Minority shareholdings (1)
- Mobile learning (1)
- Mobilität (1)
- Modeling (1)
- Modellierung (1)
- Moderne jüdische Geschichte (1)
- Mondsee (1)
- Monolayers (1)
- Morbus Alzheimer (1)
- Morphologie von Kapseln (1)
- Movement ecology (1)
- Multilayers (1)
- Muttergalaxien (1)
- NP-deletion (1)
- Nanoeisen (1)
- Nanoelektroden (1)
- Natrium-Ionen-Akkumulator (1)
- Navigation (1)
- Nehemia Robinson (1)
- Neodym-YAG-Laser (1)
- Neutronensterne (1)
- Nichtlineare Spektroskopie (1)
- Nichtlineare Wellen (1)
- Nitrogen deposition (1)
- Nonlinear waves (1)
- Numerische 2D Modellierung (1)
- ODBA (1)
- Oberflächenchemie (1)
- Oberflächenprozesse (1)
- Oberflächenzustände (1)
- OpenStreetMap (1)
- Optimization (1)
- Optode (1)
- Orogen (1)
- Orthodox Judaism (1)
- Ortscharakterisierung (1)
- Ortseffekte (1)
- Oscillating Bubble (1)
- P-Typ ATPase (1)
- P300 (1)
- P300Psychophysiology (1)
- PBCEC (1)
- PHQ-4 score (1)
- PHREEQC (1)
- PM10, PM2, PM1 (1)
- POC (1)
- Paleofloods (1)
- Paläohochwasser (1)
- Paläoklima (1)
- Paläolimnologie (1)
- Partial Little Square (1)
- Partial ownership (1)
- Peptid-Polymer-Konjugate (1)
- Perfusion (1)
- Permafrost (1)
- Permafrostdegradation (1)
- Permafrostsedimente (1)
- Permafrostökosysteme (1)
- Perowskite (1)
- Petrinetz (1)
- Phage lysins (1)
- Phagenlysine (1)
- Photochemische Reaktionen (1)
- Piano delle Concazze (1)
- Pitch Reset (1)
- Pkw (1)
- Planetary Rings (1)
- Planing (1)
- Policy Reform (1)
- Pollen (1)
- Polyelectrolyte (1)
- Polyelektrolyt (1)
- Polyneuropathie (1)
- Populationsdynamik (1)
- Portal vein (1)
- Post-Focus Reduction (1)
- Pragmatik (1)
- Preußen (1)
- Primary informatics (1)
- Prinicipal Fibre Bundles (1)
- Problem solving (1)
- Problem solving strategies (1)
- Procrustes rotation analysis (1)
- Programming environments for children (1)
- Programming learning (1)
- Prokrustes Analyse (1)
- Prolog (1)
- Propeller (1)
- Proteom (1)
- Proxyunsicherheit (1)
- Proxyverständnis (1)
- Prussia (1)
- Pseudodatensätze (1)
- Puna (1)
- Push and Pull Theories (1)
- Pytho n (1)
- QD device (1)
- QD stability (1)
- QD-Gerät (1)
- QD-Stabilität (1)
- QtClassify (1)
- Quality of regional governments (1)
- Quantenpunkt (1)
- Quantificational Variability (1)
- Quantitative Trait Locus (1)
- Quantitative Trait Locus analysis (1)
- RAFT (1)
- RAVE Beobachtungskampagne (1)
- RAVE survey (1)
- Rabbiner (1)
- Random Field Ising Model (1)
- Rat (1)
- Rechtsgeschichte (1)
- Reform Judaism (1)
- Reformjudentum (1)
- Regions (1)
- Regulation (1)
- Reionisierung (1)
- Reisen (1)
- Relativistische Astrophysik (1)
- Remote Sensing (1)
- Rezeptor (1)
- Rift (1)
- Risk Attitudes (1)
- Rotation (1)
- Runoff and streamflow (1)
- Russia (1)
- Russian Arctic (1)
- Russland (1)
- Röntgenbeugung (1)
- S. 635-644 (1)
- SAR (1)
- SEGUE Beobachtungskampagne (1)
- SEGUE survey (1)
- SOILWATER END-MEMBERS (1)
- SPAC (1)
- STEM (1)
- STG decomposition (1)
- STG-Dekomposition (1)
- STREAMWATER CHEMISTRY (1)
- Salzgestein (1)
- Salzschmelze (1)
- Salzschmelze-Templating (1)
- Sanskrit (1)
- Saprolit (1)
- Sauerstoff (1)
- Schaum (1)
- Scheibe (1)
- Schemaentdeckung (1)
- Schlüsselkompetenzen (1)
- Scientific understanding of Information (1)
- Search Frictions (1)
- Sedimentenabfolge (1)
- Segmentierung (1)
- Selbstheilende Beschichtungen (1)
- Selbstorganisation (1)
- Selen (1)
- Selenonein (1)
- Shock waves (1)
- Shortening (1)
- Sierras Pampeanas (1)
- Signalflankengraph (SFG oder STG) (1)
- Silika (1)
- Simulationen (1)
- Social Cost of Carbon (1)
- Social Identity Theory (1)
- Social impact (1)
- Sociotechnical Design (1)
- Solar corona (1)
- Sonnenkorona (1)
- Space-Time Cluster Expansions (1)
- Spalteneruption (1)
- Spannungsfeld (1)
- Species richness (1)
- Spinpolarisation (1)
- Spleißvariante (1)
- Splice Variant (1)
- Spurengasflüsse (1)
- Spätglazial (1)
- Sri Lanka (1)
- Stabile Isotope (1)
- Stabilität (1)
- Stakeholder-based Science (1)
- Stakeholder-basierte Forschung (1)
- Stalagmiten (1)
- Start-Up Subsidies (1)
- Start-up Motivation (1)
- Statistik (1)
- Steilwinkel-Analyse von PcP (1)
- Stern-Planeten-Wechselwirkung (1)
- Sterne: Entfernungen (1)
- Sternphysik (1)
- Sternwinde (1)
- Stochastic Differential Equation (1)
- Stoffwechsel (1)
- Stoßwellen (1)
- Strahlungstransport (1)
- Strain Localisation (1)
- Strukturgeologie (1)
- Styrol (1)
- Subduction (1)
- Subduktion (1)
- Subsidenzgeschichte (1)
- Succession (1)
- Supernovaüberreste (1)
- Survival (1)
- Synthese (1)
- Synthesis (1)
- Systeme interagierender Partikel (1)
- Systems Biology (1)
- Süd-Türkei (1)
- TRACERS (1)
- TRPV1 (1)
- Tauziehen (1)
- Teaching problem solving strategies (1)
- Team Composition (1)
- Team Development (1)
- Technique (1)
- Tektonik (1)
- Temperaturproxy (1)
- Tensid (1)
- Thermokarstprozesse (1)
- Tibet Plateau (1)
- Tibetan Plateau (1)
- Tiefbeben und Kernexplosionen (1)
- Tomate (1)
- Tomato (1)
- Topic (1)
- Torsion Experiments (1)
- Torsionsexperimente (1)
- Trajectories (1)
- Transformation (1)
- Treibhausgasemissionen (1)
- Triazin (1)
- Tsunami (1)
- Turbulenz (1)
- UNITED-STATES (1)
- UV-detection (1)
- Ultra-Niedriggeschwindigkeitszonen (1)
- Understorey (1)
- Uniform pricing (1)
- Unintended Consequence (1)
- Union (1)
- Unsicherheiten (1)
- Unsicherheitsanalyse (1)
- Urate (1)
- VLT/MUSE (1)
- VOC (1)
- VP-ellipsis (1)
- Vascular plants (1)
- Vegetation (1)
- Vegetationsmodell (1)
- Verkürzung (1)
- Versöhnung (1)
- Vertical flux (1)
- Vertical integration (1)
- Verwitterungsfeedback (1)
- Videoanalyse (1)
- Visual Oddball Paradigm (1)
- Vorland (1)
- Vorlandbecken (1)
- Vulkan Verformung (1)
- Vulkanologie (1)
- Vulnerabilität (1)
- Warven (1)
- Warves (1)
- Wasser-Gesteins-Wechselwirkungen (1)
- Wasser/Luft Grenzflächen (1)
- Wasserhaushalt (1)
- Weathering (1)
- Weitwinkelröntgenstreuung (1)
- Wh-question (1)
- Whinterrogatives (1)
- Windböen (1)
- Winderosion (1)
- Wissenschaftsgeschichte (1)
- Wissensgeschichte (1)
- Women and IT (1)
- Word processing (1)
- Wärmefluss (1)
- Wärmekapazität (1)
- X-ray diffraction (1)
- XM (1)
- Zink (1)
- Zirkulardichroismus (1)
- Zyklone (1)
- Züchtung (1)
- [N]phenylene dyads (1)
- [N]phenylenes (1)
- academic leadership (1)
- acclimation (1)
- acoustically levitated droplets (1)
- active galactic nuclei (1)
- ad hoc learning (1)
- ad hoc messaging network (1)
- adaptation (1)
- adsorption (1)
- aerosol: hygroscopic growth (1)
- aerosol: hygroskopisches Wachstum (1)
- aerosol: optical properties (1)
- aerosol: optische Eigenschaften (1)
- affect (1)
- air pollution (1)
- aktive Galaxienkerne (1)
- akustisch schwebende Tropfen (1)
- alga (1)
- alpha (1)
- aluminum alloy (1)
- ambient vibration (1)
- ambiguity attitudes (1)
- anaerobe Inkubationensexperimente (1)
- anaerobic incubation experiments (1)
- angle resolved photoelectron spectroscopy (1)
- answer set programming (1)
- anterior PNP (1)
- antibody (1)
- archetype (1)
- arctic (1)
- arktische Tundra (1)
- arktischer Dunst (1)
- arktisches Aerosol (1)
- astronomy (1)
- atmospheric science (1)
- bacteria (1)
- basaltic volcanoes (1)
- behavioral economics (1)
- behaviour (1)
- benchmarking (1)
- bidirectional intracellular transport (1)
- bidirektionaler intrazellulärer Transport (1)
- bild (1)
- binding interactions (1)
- bioconjugate (1)
- biofilm (1)
- biohybrid molecules (1)
- biomolecule (1)
- biophotonics (1)
- biorefinery (1)
- black holes (1)
- blended learning (1)
- bottom–up (1)
- boundary layer (1)
- breeding (1)
- built–in predicates (1)
- bulge (1)
- business services (1)
- canonical discretization schemes (1)
- capacity building (1)
- capillary electrophoresis (1)
- capsule morphology (1)
- carbon cycle (1)
- carbon cycling (1)
- carbon debt (1)
- carbon emissions (1)
- carbon materials (1)
- carbon nitride (1)
- carbon price (1)
- carbon removal (1)
- cartel (1)
- cathode (1)
- central Andes (1)
- central-eastern Beringia (1)
- chalcogenide (1)
- charnockite (1)
- chemical weathering (1)
- chemische Verwitterung (1)
- childcare provision (1)
- chlorbenzol (1)
- chronic pain (1)
- chronischer Schmerz (1)
- circular dichroism (1)
- citrazinic acid (1)
- climate (1)
- climate data (1)
- climate networks (1)
- climate physics (1)
- clustering (1)
- coating (1)
- coherence (1)
- collaboration (1)
- colloidal quantum dot (1)
- collusion (1)
- color change (1)
- communication (1)
- community (1)
- commuting (1)
- competence (1)
- complement (1)
- completion rates (1)
- complex emulsion (1)
- complex systems (1)
- complexity (1)
- composition (1)
- computational thinking (1)
- computer science (1)
- computing science education (1)
- concept of algorithm (1)
- conditioned (1)
- conditioned Feller diffusion (1)
- conjunction (1)
- constrained Hamiltonian systems (1)
- constraint (1)
- constructionism (1)
- consumer (1)
- control resynthesis (1)
- cooperative phenomena (1)
- cooperative transport (1)
- core-mantle boundary (1)
- covalent frameworks (1)
- critical and subcritical Dawson-Watanabe process (1)
- critical collapse (1)
- critical zone (1)
- crops (1)
- crowding out (1)
- cultivation (1)
- cultural pluralism (1)
- cyclones (1)
- damage modeling (1)
- damage modelling (1)
- data analysis (1)
- data integration (1)
- data profiling (1)
- data-mining (1)
- decomposition (1)
- decomposition methods (1)
- deductive databases (1)
- deep earthquakes and nuclear explosions (1)
- deep eutectic solvents (1)
- definite descriptions (1)
- density-driven flow (1)
- deoxyfructosazine (1)
- derivational complexity (1)
- detailed balance equation (1)
- deutsch-jüdische Geschichte (1)
- developing country cities (1)
- diamond anvil cell (1)
- dichlorbenzol (1)
- dichlorobenzene (1)
- dichtegetriebene Strömung (1)
- dielectrophoresis (1)
- differential-algebraic equations (1)
- disc (1)
- discotics (1)
- discourse comprehension (1)
- discrete choice (1)
- discrimination (1)
- diversity (1)
- doctoral studies (1)
- double dividend (1)
- drug delivery (1)
- dünne Filme (1)
- e-learning platform (1)
- early indicators for SLI (1)
- earth mantle (1)
- economic impacts (1)
- ecophysiology (1)
- education (1)
- efficiency (1)
- elastic coupling (1)
- elastische Kopplung (1)
- electrochemistry (1)
- emergency-aid (1)
- emission line classification (1)
- employment precariousness (1)
- emulsion (1)
- enantioselectivity (1)
- encapsulation (1)
- energy expenditure (1)
- engaged computing (1)
- entrepreneurship policy (1)
- environmental tax reform (1)
- enzymatic conjugation (1)
- equity crowdfunding (1)
- erosion (1)
- europe (1)
- european (1)
- europäische Geschichte (1)
- ex-situ focus (1)
- exoplanet atmospheres (1)
- exoplanets (1)
- extensions of logic programs (1)
- family (1)
- feature selection (1)
- ferropericlase (1)
- finance (1)
- financial access and inclusion (1)
- firn (1)
- fissure eruption (1)
- flexibility (1)
- flood risk (1)
- flow (1)
- fluorescence immunoassay (1)
- fluorinated polymers (1)
- foam (1)
- focus (1)
- focus marker (1)
- focus marking (1)
- focus movement (1)
- food prices (1)
- forestry (1)
- forward / backward chaining (1)
- fruit (1)
- function symbols (1)
- fundamental parameters (1)
- fundamentale Parameter (1)
- galactic astronomy (1)
- galaktische Astronomie (1)
- galaxy clusters (1)
- galaxy: general (1)
- gas geochemistry (1)
- gemeinsame Inversion (1)
- gender pay gap (1)
- general secondary education (1)
- generalized difference-in-difference (1)
- generalized logic programs (1)
- geodynamics (1)
- geothermal exploration (1)
- geothermal monitoring (1)
- geothermische Exploration (1)
- geothermische Überwachung (1)
- gepulster DPSS Laser (1)
- glacier forefield (1)
- global change (1)
- glucose (1)
- goal-setting (1)
- grafting-from (1)
- grazer (1)
- grazing (1)
- green chemistry (1)
- gridded data (1)
- großräumige Struktur des Universums (1)
- gyrochronology (1)
- habit formation (1)
- hard core potential (1)
- hate crime (1)
- heat capacity (1)
- heat flux (1)
- heptazine (1)
- herbivore (1)
- heteroatom-doped carbons (1)
- heteroatom-dotierte Kohlenstoffe (1)
- heterogene Katalyse (1)
- heterogeneous catalysis (1)
- hierarchical porosity (1)
- hierarchische Porosität (1)
- high pressure (1)
- high resolution (1)
- high-redshift (1)
- history of science (1)
- hohe Auflösung (1)
- hoher Rotverschiebung (1)
- home office (1)
- horizontal equity (1)
- horizontal-vertikales Spektralverhältnis (1)
- horizontaler Fluss (1)
- host galaxies (1)
- human capital (1)
- human excised skin (1)
- hydro-meteorological risk (1)
- hydro-meteorologische Risiken (1)
- hydrodynamic modeling (1)
- hydrodynamische Modellierung (1)
- hydrolysis (1)
- hyperaccumulation (1)
- hyperspectral remote sensing (1)
- hyperspektral Fernerkundung (1)
- hysteresis (1)
- ice core (1)
- ice sheet (1)
- image (1)
- imaging spectroscopy (1)
- impact (1)
- income (1)
- inequality (1)
- inequality of opportunity (1)
- influenza (1)
- informatics curricula (1)
- informatics education (1)
- informatics in upper secondary education (1)
- information structure (1)
- inorganic ions (1)
- instruction (1)
- instrumental variables (1)
- integration by parts formula (1)
- intellectual history (1)
- interacting particle systems (1)
- international comparison (1)
- international cooperation (1)
- international study (1)
- internationalisation for higher education (1)
- interreligious dialogue (1)
- interreligiöser Dialog (1)
- intonation (1)
- intracellular transport (1)
- intracluster medium (1)
- intrazellulärer Transport (1)
- inversion (1)
- ion mobility spectrometry (1)
- ionothermal synthesis (1)
- isotope variations (1)
- job characteristics (1)
- joint inversion (1)
- just transition (1)
- jüdische Orthodoxie (1)
- knowledge representation (1)
- kolloidaler Quantenpunkt (1)
- komplexe Emulsion (1)
- komplexe Systeme (1)
- kooperative Phänomene (1)
- kooperativer Transport (1)
- kovalente Rahmenbedingungen (1)
- kritische Zone (1)
- kritischer Kollaps (1)
- kultureller Pluralismus (1)
- lab-on-chip (1)
- labor productivity (1)
- labour migration (1)
- lactate output (1)
- lake sediments (1)
- langreichweitige Korrelationen (1)
- language acquisition (1)
- large-scale structure (1)
- late talker (1)
- lava fountains (1)
- layered compounds (1)
- leadership (1)
- lebende Materialien (1)
- legal history (1)
- lesson (1)
- life history (1)
- light-programmable viscosity (1)
- lignin (1)
- linked employer-employee data (1)
- liquid crystals (1)
- living materials (1)
- logic programming (1)
- logical signaling networks (1)
- logische Signalnetzwerke (1)
- long-memory (1)
- long-range dependence (1)
- long-term effects (1)
- low back pain (1)
- lubricant (1)
- lysimeter (1)
- ländliche Entwicklung (1)
- lösungsmittelfreie Synthese (1)
- magnetic fields (1)
- magnetism (1)
- magnetoelasticity (1)
- mandatory computer science foundations (1)
- market-entry game (1)
- markov processes (1)
- maschinelles Lernen (1)
- mass loss (1)
- mass spectrometry (1)
- massereiche Sterne (1)
- massive stars (1)
- mechanobiology (1)
- medical (1)
- medizinisch (1)
- mehrfache Stressfaktoren (1)
- mehrschichtige Verbindungen (1)
- memory studies (1)
- mesocrystals (1)
- mesoporous (1)
- mesoporös (1)
- meta-analysis (1)
- metabolic genomics (1)
- metabolite breeding (1)
- metabolite profiling (1)
- metabolome (1)
- metadata discovery (1)
- metadata quality (1)
- metamorphosis (1)
- meteorology (1)
- methane cycle (1)
- miRNA (1)
- micro- and nanotechnologies (1)
- microbial communities (1)
- microbial processes (1)
- microplate (1)
- microswimmers (1)
- microwave synthesis (1)
- microzonation (1)
- mikrobielle Gemeinschaften (1)
- mikrobielle Prozesse (1)
- mineral weathering reactions (1)
- misconceptions (1)
- mixed methods (1)
- mixture of bridges (1)
- mobility (1)
- mock data catalogues (1)
- modality (1)
- modifizierte räumliche Autkorrelationsmethode (1)
- molecular biomarkers (1)
- molekulare Biomarker (1)
- monensin (1)
- monochlorobenzene (1)
- monosaccharides (1)
- mother’s labor supply (1)
- multi-valued logic (1)
- multi-valued treatment (1)
- multidisciplinary intervention (1)
- multiple stress factors (1)
- multiresponsiv (1)
- multiresponsive (1)
- multitype measure-valued branching processes (1)
- nZVI (1)
- nachhaltige Energiespeichermaterialien (1)
- nano zero-valent iron (1)
- nanoelectrodes (1)
- nanogels (1)
- narrative structure (1)
- national multiplication training (1)
- national quality assurance agency in Guinea (1)
- natural field experiment (1)
- net-negative emissions (1)
- neutron stars (1)
- nichtgenestete Modellselektion (1)
- nineteenth century (1)
- noise (1)
- non-Ricardian households (1)
- non-manuals (1)
- non-nested model selection (1)
- nonlinear dynamics (1)
- nonlinear optics (1)
- numerical astrophysics (1)
- numerical modelling (1)
- numerical relativity (1)
- numerische Astrophysik (1)
- numerische Modellierung (1)
- numerische Relativitätstheorie (1)
- obesity (1)
- objective health measures (1)
- offene Daten (1)
- open data (1)
- optical properties (1)
- optische Eigenschaften (1)
- optode (1)
- organic matter (1)
- organisches Material (1)
- ortsverteile faseroptische Dehnungsmessung (1)
- oscillating bubble (1)
- osteuropäisch-jüdische Geschichte (1)
- oxygen (1)
- p-type ATPase (1)
- palaeoclimate (1)
- paleolimnology (1)
- paraconsistency (1)
- participatory didactics (1)
- peacebuilding (1)
- peptide synthesis (1)
- peptide-polymer conjugate (1)
- periglacial landscape evolution (1)
- periglacial landscapes (1)
- periglaziale Landschaften (1)
- periglaziale Landschaftsentwicklung (1)
- permafrost (1)
- permafrost degradation (1)
- permafrost ecosystems (1)
- permafrost sediments (1)
- perovskite (1)
- personal initiative (1)
- pervasive learning (1)
- petri net (1)
- phase synchronization (1)
- photochemical reactions (1)
- photoinduced electron transfer (1)
- photoresponse (1)
- photosynthesis (1)
- physical activity (1)
- physiology (1)
- plateau uplift (1)
- point-of-care (1)
- political ideology (1)
- political opportunism (1)
- political speech (1)
- pollution (1)
- polymerization (1)
- polyneuropathy (1)
- population density (1)
- population dynamics (1)
- porous materials (1)
- poröse Materialien (1)
- post-depositional (1)
- posterior P600 (1)
- pragmatics (1)
- predictability (1)
- print culture (1)
- probabilistic approach (1)
- probabilistic processing (1)
- probabilistischer Ansatz (1)
- processing (1)
- processing of phonological details (1)
- productivity slowdown (1)
- programmable friction (1)
- promises (1)
- propellers (1)
- property taxes (1)
- proposal writing (1)
- prostaglandin-f2-alpha (1)
- protein (1)
- proteome (1)
- proxy uncertainty (1)
- proxy understanding (1)
- public good (1)
- public universities in Kenya (1)
- pulsed DPSS laser (1)
- quality assurance (1)
- quality assurance in Guinean higher education (1)
- quality assurance structures (1)
- quality culture (1)
- quality evaluation (1)
- quality in higher education (1)
- quasiparticle interactions (1)
- rabbis (1)
- radiative transfer (1)
- reactive transport (1)
- reaktiver Transport (1)
- receptor (1)
- reciprocal processes (1)
- reciprocal relationship (1)
- recombinant inbred line (1)
- reconciliation (1)
- redistribution (1)
- reflective breadth (1)
- reflective depth (1)
- reflective skills (1)
- refugees (1)
- reionization (1)
- relative clause (1)
- relativistic hydrodynamics (1)
- relativistische Hydrodynamik (1)
- religious education (1)
- religiöse Bildung (1)
- remediation (1)
- removal subsidies (1)
- renewable energy (1)
- renewable energy subsidies (1)
- representative longitudinal survey data (1)
- representative real-time survey data (1)
- resilience (1)
- return level estimation (1)
- returns to education (1)
- revenue recycling (1)
- reversible measure (1)
- rift (1)
- rising bubble (1)
- risk attitudes (1)
- rotation (1)
- rural development (1)
- russische Arktis (1)
- räumlich explizit (1)
- räumliche Analyse (1)
- räumliche Autkorrelationsmethode (1)
- räumliche Autokorrelation (1)
- salt melt (1)
- salt melt templating (1)
- salt rock (1)
- saprolite (1)
- schema discovery (1)
- school health examinations (1)
- schwarze Löcher (1)
- science (1)
- sea ice (1)
- sedimentary record (1)
- segmentation (1)
- seismic noise (1)
- seismisches Rauschen (1)
- selenium (1)
- selenoneine (1)
- self-assembly (1)
- self-employed (1)
- self-healing coatings (1)
- self-organization (1)
- self-rated health (1)
- selfefficacy (1)
- semantic incongruity (1)
- semantics (1)
- seston (1)
- sign languages (1)
- signal transition graph (1)
- silica nanoparticles (1)
- simulation (1)
- single-atom catalysis (1)
- site characterization (1)
- site effects (1)
- situated learning (1)
- skin penetration (1)
- social capital (1)
- social network (1)
- social networking (1)
- sodium-ion batteries (1)
- soft and hard templating (1)
- soft information (1)
- soil (1)
- soil analysis (1)
- solvent-free reactions (1)
- sortagging (1)
- sortaseA (1)
- sorting (1)
- source model (1)
- southern Turkey (1)
- space-time Gibbs field (1)
- spatial analyses (1)
- spatial autocorrelation (1)
- spatially explicit (1)
- spatially explicit model (1)
- spectroscopy (1)
- speed independent (1)
- spin resolved photoelectron spectroscopy (1)
- spin-orbit coupling (1)
- spinaufgelöste Photoelektronenspektroskopie (1)
- spindown (1)
- spiropyran copolymer (1)
- spoken discourse (1)
- spreadsheets (1)
- stabile Isotope (1)
- stabile Schichtung (1)
- stability (1)
- stable stratification (1)
- stag-hunt game (1)
- stalagmites (1)
- star-planet interaction (1)
- stark eutektisches Lösungsmittel (1)
- stars: distances (1)
- statistical physics (1)
- statistics (1)
- statistische Physik (1)
- steep-angle analysis of PcP (1)
- steigende Blasen (1)
- stellar content (1)
- stellar physics (1)
- stellar winds (1)
- stellarer Inhalt (1)
- stochastic bridge (1)
- stocking capacity (1)
- strategic-uncertainty attitudes (1)
- stratification (1)
- stress field (1)
- strike-slip (1)
- structural and operational changes (1)
- structural geology (1)
- styrene (1)
- subjective survival probability (1)
- subsidence history (1)
- supercritical carbon dioxide (scCO₂) (1)
- supernova remnants (1)
- surface chemistry (1)
- surface processes (1)
- surface rheology (1)
- surface states (1)
- surfactants (1)
- survey (1)
- sustainability (1)
- sustainable energy storage materials (1)
- switchSENSE (1)
- switchSENSE Technologie (1)
- symplectic methods (1)
- systems biology (1)
- sättigbarer Absorber (1)
- tacrolimus formulation (1)
- tax competition (1)
- taxpayer subsidies (1)
- teacher (1)
- teacher education (1)
- teacher training (1)
- teaching material (1)
- tectonics (1)
- temperature proxy (1)
- temperature variability (1)
- terms-of-trade effects (1)
- test items (1)
- thermokarst processes (1)
- theta (1)
- thin films (1)
- time reversal (1)
- time reversal symmetry (1)
- tone languages (1)
- topics (1)
- topography (1)
- topological insulators (1)
- topologische Isolatoren (1)
- top– down (1)
- trace gas fluxes (1)
- trade (1)
- training for sustainability (1)
- training programme (1)
- transatlantic history (1)
- transatlantische Geschichte (1)
- transformation (1)
- transformation products (1)
- transformative justice (1)
- transition economy (1)
- transition metals (1)
- transitional justice (1)
- travel (1)
- treatment effects (1)
- triazine (1)
- tug-of-war (1)
- turbulence (1)
- two-dimensional (1)
- typology (1)
- ultra-low velocity zones (1)
- ultrafast (1)
- ultraschnell (1)
- uncertainty (1)
- uncertainty analysis (1)
- unemployment (1)
- unilateral climate policy (1)
- university leadership in Malaysia (1)
- university management (1)
- vegetation (1)
- vegetation model (1)
- velocity model (1)
- verbal irony (1)
- verbale Ironie (1)
- vertikaler Fluss (1)
- veterinary drugs (1)
- video analysis (1)
- vocational education (1)
- volcanic tremor (1)
- volcano deformation (1)
- volcanology (1)
- voting (1)
- voucher (1)
- vulkanischer Tremor (1)
- vulnerability (1)
- water balance (1)
- water rock interactions (1)
- wealth (1)
- weathering feedback (1)
- weiche und harte Templatierung (1)
- welfare and gender regimes (1)
- wh-ex-situ (1)
- wh-in-situ (1)
- wh-questions (1)
- wide-angle x-ray scattering (1)
- wind gusts (1)
- winderosion (1)
- windfall gains (1)
- winkelaufgelöste Photoelektronenspektroskopie (1)
- zentral-östliches Beringia (1)
- zentralen Anden (1)
- zinc (1)
- Ätna (1)
- Ökologie (1)
- Ökotoxikologie (1)
- Übergangsjustiz (1)
- Übergangsmetalle (1)
- ökonomische Auswirkungen (1)
- überkritisches Kohlendioxid (scCO₂) (1)
Institute
- Extern (440)
- Institut für Physik und Astronomie (41)
- Institut für Geowissenschaften (37)
- Vereinigung für Jüdische Studien e. V. (34)
- Center for Economic Policy Analysis (CEPA) (32)
- Institut für Chemie (31)
- Fachgruppe Volkswirtschaftslehre (27)
- Institut für Biochemie und Biologie (19)
- Department Psychologie (17)
- Department Linguistik (16)
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
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.
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.
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.
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.
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.
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.
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.
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.
Discussion : X-rays
(2007)
Dynamical simulation of the “velocity-porosity” reduction in observed strength of stellar wind lines
(2007)
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.
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.
General Discussion
(2007)
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.
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.
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.
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.
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.
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.
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.
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.
Clumping in Galactic WN stars : a comparison of mass loss rates from UV/optical & radio diagnostics
(2007)
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.
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.
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.
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.
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.
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.
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).
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.
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.
Clumping in O-star winds
(2007)
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.
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.
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.
Significant seasonal variation in size at settlement has been observed in newly settled larvae of Dreissena polymorpha in Lake Constance. Diet quality, which varies temporally and spatially in freshwater habitats, has been suggested as a significant factor influencing life history and development of freshwater invertebrates. Accordingly, experiments were conducted with field-collected larvae to test the hypothesis that diet quality can determine planktonic larval growth rates, size at settlement and subsequent post-metamorphic growth rates. Larvae were fed one of two diets or starved. One diet was composed of cyanobacterial cells which are deficient in polyunsaturated fatty acids (PUFAs), and the other was a mixed diet rich in PUFAs. Freshly metamorphosed animals from the starvation treatment had a carbon content per individual 70% lower than that of larvae fed the mixed diet. This apparent exhaustion of larval internal reserves resulted in a 50% reduction of the postmetamorphic growth rates. Growth was also reduced in animals previously fed the cyanobacterial diet. Hence, low food quantity or low food quality during the larval stage of D. polymorpha lead to irreversible effects for postmetamorphic animals, and is related to inferior competitive abilities.
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?
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.
The factors that determine the efficiency of energy transfer in aquatic food webs have been investigated for many decades. The plant-animal interface is the most variable and least predictable of all levels in the food web. In order to study determinants of food quality in a large lake and to test the recently proposed central importance of the long-chained eicosapentaenoic acid (EPA) at the pelagic producer-grazer interface, we tested the importance of polyunsaturated fatty acids (PUFAs) at the pelagic producerconsumer interface by correlating sestonic food parameters with somatic growth rates of a clone of Daphnia galeata. Daphnia growth rates were obtained from standardized laboratory experiments spanning one season with Daphnia feeding on natural seston from Lake Constance, a large pre-alpine lake. Somatic growth rates were fitted to sestonic parameters by using a saturation function. A moderate amount of variation was explained when the model included the elemental parameters carbon (r2 = 0.6) and nitrogen (r2 = 0.71). A tighter fit was obtained when sestonic phosphorus was incorporated (r2 = 0.86). The nonlinear regression with EPA was relatively weak (r2 = 0.77), whereas the highest degree of variance was explained by three C18-PUFAs. The best (r2 = 0.95), and only significant, correlation of Daphnia's growth was found with the C18-PUFA α-linolenic acid (α-LA; C18:3n-3). This correlation was weakest in late August when C:P values increased to 300, suggesting that mineral and PUFA-limitation of Daphnia's growth changed seasonally. Sestonic phosphorus and some PUFAs showed not only tight correlations with growth, but also with sestonic α-LA content. We computed Monte Carlo simulations to test whether the observed effects of α-LA on growth could be accounted for by EPA, phosphorus, or one of the two C18-PUFAs, stearidonic acid (C18:4n-3) and linoleic acid (C18:2n-6). With >99 % probability, the correlation of growth with α-LA could not be explained by any of these parameters. In order to test for EPA limitation of Daphnia's growth, in parallel with experiments on pure seston, growth was determined on seston supplemented with chemostat-grown, P-limited Stephanodiscus hantzschii, which is rich in EPA. Although supplementation increased the EPA content 80-800x, no significant changes in the nonlinear regression of the growth rates with α-LA were found, indicating that growth of Daphnia on pure seston was not EPA limited. This indicates that the two fatty acids, EPA and α-LA, were not mutually substitutable biochemical resources and points to different physiological functions of these two PUFAs. These results support the PUFA-limitation hypothesis for sestonic C:P < 300 but are contrary to the hypothesis of a general importance of EPA, since no evidence for EPA limitation was found. It is suggested that the resource ratios of EPA and α-LA rather than the absolute concentrations determine which of the two resources is limiting growth.