Filtern
Erscheinungsjahr
- 2015 (288) (entfernen)
Dokumenttyp
- Dissertation (288) (entfernen)
Sprache
- Englisch (157)
- Deutsch (126)
- Französisch (2)
- Spanisch (2)
- Italienisch (1)
Gehört zur Bibliographie
- ja (288) (entfernen)
Schlagworte
- Klimawandel (3)
- climate change (3)
- Arbeitsgedächtnis (2)
- Aspekt (2)
- Bakteriophagen (2)
- Erosion (2)
- Germany (2)
- Geschäftsprozessmanagement (2)
- Modellierung (2)
- Nanopartikel (2)
- Psycholinguistik (2)
- Satzverarbeitung (2)
- Schriftspracherwerb (2)
- Seesedimente (2)
- Simulation (2)
- Syntax (2)
- Wasser (2)
- Wirtschaft (2)
- erosion (2)
- formal semantics (2)
- lake sediments (2)
- mass wasting (2)
- numerische Modellierung (2)
- protein (2)
- psycholinguistics (2)
- regional climate model (2)
- sentence processing (2)
- simulation (2)
- stabile Isotope (2)
- thermoresponsive (2)
- water (2)
- working memory (2)
- "Omik"-Technologien (1)
- 19. Century (1)
- 19. Jahrhundert (1)
- ACT-R (1)
- Abhängigkeitsauflösung (1)
- Abschätzung der Unsicherheiten (1)
- Abstraktion (1)
- Accountability (1)
- Adhäsionsproteine (1)
- Adipositas (1)
- Aerosole (1)
- African languages (1)
- Alfred Döblin (1)
- Alkohol (1)
- Altlasten (1)
- Analphabetismus (1)
- Analyse (1)
- Antibiotikaresistenz (1)
- Antwortspektren (1)
- Apis mellifera (1)
- Arbeitslosigkeit (1)
- Arbeitsmarktpolitik (1)
- Arbeitsteilung (1)
- Argentina (1)
- Argentinien (1)
- Arktis (1)
- Armut (1)
- Arthur Ewert (1)
- Aspect (1)
- Asteroiden (1)
- Astronomie (1)
- Astrophysik (1)
- Autonomie (1)
- Avantgarde (1)
- Awara (1)
- BPA (1)
- Bankenregulierung (1)
- Beirat (1)
- Beteiligungen (1)
- Beteiligungssteuerung (1)
- Betreuung (1)
- Bevölkerungsmarketing (1)
- Bezugsgruppen (1)
- Bioaktivität (1)
- Biogas (1)
- Biomechanik (1)
- Biosensor (1)
- Bisphenol A (1)
- Bistabilität (1)
- Blattwachse (1)
- Blickbewegungen (1)
- Boden (1)
- Bodenbewegung (1)
- Bodenbewegungsmodelle (1)
- Brasilien im November 1935 (1)
- Brazil November 1935 (1)
- Brillouin Streuung (1)
- Brillouin scattering (1)
- Budgetstudie (1)
- Budgetstudien (1)
- Bürgerbeteiligung (1)
- Bürgerhaushalt (1)
- Büro der Kommunistischen Internationale in Shanghai (1)
- Calcineurin (1)
- Calcineurin-Inhibitoren (1)
- Carbo-Iron (1)
- Carbo-Iron® (1)
- Cerrado (1)
- Chadic (1)
- Chemotaxis (1)
- Chinese (1)
- Chinesisch (1)
- Ciliaten (1)
- Cold War (1)
- Colombia (1)
- Communist International (1)
- Communist International Shanghai office (1)
- Communist Party of Germany (KPD) (1)
- Computational Fluid Dynamics (CFD) (1)
- Computermodell (1)
- Coriolis Effekt (1)
- Coriolis effect (1)
- Coulomb stress (1)
- Coulombspannung (1)
- Critical Discourse Analysis (1)
- DANSER (1)
- DNA (1)
- Darmbakterium (1)
- Daseinsvorsorge (1)
- Daten (1)
- Datenextraktion (1)
- Datenfilter (1)
- Datenkorrektheit (1)
- Datenobjekte (1)
- Datenzustände (1)
- Dauer der Bodenbewegung (1)
- Dawn mission (1)
- Dawn-Mission (1)
- Dead Sea (1)
- Debus-Radziszewski polymerization (1)
- Deformation (1)
- Demografiepolitik (1)
- Demografisierung (1)
- Demokratie (1)
- Denitrifikation (1)
- Denudation (1)
- Deutsch (1)
- Deutsch als Fremdsprache (1)
- Deutsche Demokratische Republik (1)
- Deutschland (1)
- Dialectology (1)
- Dialektologie (1)
- Dictyostelium (1)
- Difference-in-Difference (1)
- Diskurs (1)
- Domänenwandbewegung (1)
- Doppler Imaging (1)
- Doppler imaging (1)
- EEG (1)
- ETAS Modell (1)
- ETAS model (1)
- East African Rift (1)
- Eastern Cordillera (1)
- Einfluß des Sonnenwindes und des interplanetaren magnetischen Feldes (1)
- Einschlagskrater (1)
- Einschlagssimulation (1)
- Electrical Resistivity Tomography (ERT) (1)
- Elektrische Widerstandstomographie (ERT) (1)
- Elliptic complexes (1)
- Elliptische Komplexe (1)
- Emissionen (1)
- EnMAP Satellit (1)
- EnMAP satellite (1)
- Energierecht (1)
- Englisch (1)
- Ensemblesimulationen (1)
- Enzym (1)
- Equol (1)
- Erdbeben (1)
- Erdbebengefährdungsabschätzungen (1)
- Erdbebenvorhersage (1)
- Erdbebenwechselwirkung (1)
- Erdmantel (1)
- Ereignisabstraktion (1)
- Erinnerungskultur (1)
- Ernährungsmuster (1)
- Ernährungsumstellung (1)
- Ertragslücken (1)
- Erwachsenenbildung (1)
- Erzählen (1)
- Eulerian grid (1)
- Eulerische Gitter (1)
- Eurasian active margin (1)
- Eurasischer aktiver Kontinentalrand (1)
- Europarecht / Europäische Verfassung (1)
- Europäische Verfassung (1)
- Evaluation (1)
- Evaluation aktiver Arbeitsmarktpolitik (1)
- Evolution (1)
- Exhumationsprozesse (1)
- Extremereignisse (1)
- Familienstand (1)
- Fermentation (1)
- Fernerkundung (1)
- Fernerkundungsdaten (1)
- Film (1)
- Filming. A Love Story (1)
- Finanzierungsformen (1)
- Fixationsbewegungen der Augen (1)
- Flachseen (1)
- Fluoreszenzsensor (1)
- Flussbettmorphologie (1)
- Flussfotolyse (1)
- Flutschäden (1)
- Fokus (1)
- Fokussensitivität (1)
- Food Chain (1)
- Formale Semantik (1)
- Formationsfluid (1)
- Fourier spectra (1)
- Fourier-Spektren (1)
- France (1)
- Frankreich (1)
- Fredholm Komplexe (1)
- Fredholm complexes (1)
- Futtermittel (1)
- Futtermittel für Wiederkäuer (1)
- Fällungsreaktion (1)
- Förderprogramm (1)
- Galaxienentstehung (1)
- Galaxienphysik (1)
- Gashydrate (1)
- Gebirgshydrologie (1)
- Geoinformatik (1)
- Geologie (1)
- Geophysik (1)
- Geovisualisierung (1)
- German (1)
- German Democratic Republic (1)
- German border region neighbouring with Poland (1)
- German literature (1)
- Germanistik (1)
- Geschmacksrezeptor (1)
- Glucagon (1)
- Glycosylierung (1)
- Grassfields Bantu (1)
- Green Biorefinery (1)
- Grenzziehungsarbeit (1)
- Ground Motion Prediction Equation (GMPE) (1)
- Groß Schönebeck (1)
- Grundschüler/innen (1)
- Gründungsförderung (1)
- Guerre froide (1)
- HEK293 (1)
- HP/LT metamorphism (1)
- HP/LT-Metamorphose (1)
- HPµF (1)
- Hangerosion (1)
- Haushaltseinkommen (1)
- Henlesche Schleife (1)
- Herkunft (1)
- Hindi film (1)
- Hochschuldidaktik (1)
- Hochwasser (1)
- Hochwasserrekonstruktion (1)
- Holocaust (1)
- Holocene (1)
- Holozän (1)
- Honigbiene (1)
- Hydrogel (1)
- Hyperschall (1)
- Hyperschall Propagation (1)
- Hyperspektral (1)
- ICT competencies (1)
- IGF-1 (1)
- Index Theorie (1)
- Index theory (1)
- Indian English novel (1)
- Indian cinema (1)
- Indien (1)
- Informatikdidaktik (1)
- Informatische Kompetenzen (1)
- Infrarot (1)
- Infrastructure Covered Bond (1)
- Infrastrukturfinanzierung (1)
- Instabilität (1)
- Insulin-induzierte Hypoglykämie (1)
- Interaktion (1)
- Interaktionsanalyse (1)
- Interkulturelle Äquivalenz (1)
- Intermedialität (1)
- Irrfahrten auf Graphen (1)
- Isoflavone (1)
- Isábena Einzugsgebiet (1)
- Isábena catchment (1)
- Kabelbelegung (1)
- Kalibrierung von Spektrografen (1)
- Kalter Krieg (1)
- Kapitalmarkt (1)
- Kapitalmarktrelevanz (1)
- Karbonate (1)
- Kinetik (1)
- Kleegras (1)
- Klimaanpassung (1)
- Koaleszenz (1)
- Kohlenstoffnitride (1)
- Kohlenstoffspeicher (1)
- Kolloidtransport (1)
- Kolumbien (1)
- Kommunismus (1)
- Kommunistische Internationale (1)
- Kommunistische Partei Deutschlands (1)
- Kompetenzen (1)
- Komposite (1)
- Konvergenzkriterien (1)
- Konversationsanalyse (1)
- Konzentration (1)
- Koppelung (1)
- Kopplung zwischen Magnetosphäre, Ionosphäre und Thermosphäre (1)
- Koregistrierung (1)
- Koronarangiographie (1)
- Korrosion (1)
- Kosmologie: Beobachtungen (1)
- Kosten-Nutzen-Analyse (1)
- Kritische Diskursanalyse (1)
- Kräftedreieck (1)
- Kultur (1)
- Körpergewichsterhalt (1)
- Körpergewichtsverlust (1)
- Küstenerosion (1)
- Küstenfluten (1)
- L1 Polish (1)
- L2 German (1)
- Landnutzung (1)
- Landnutzungswandel (1)
- Landschaftsentwicklung (1)
- Langzeitaustrocknung (1)
- Lebensmittelkette (1)
- Lebensmittelnachfrage (1)
- Lehrerbildung (1)
- Lehrpotential (1)
- Lehrtext (1)
- Lernen (1)
- Linguistik (1)
- Lipopolysaccharid (1)
- Literatur (1)
- Luzerne (1)
- MRSA (1)
- Magnetotellurik (1)
- Managementroutinen (1)
- Marangoni flow (1)
- Marangoni-Fluss (1)
- Marke (1)
- Markenpersönlichkeit (1)
- Marketing (1)
- Mars (1)
- Marsanaloge Regolithe (1)
- Martian regolith analogs (1)
- Massenbewegungen (1)
- Massenbewegungsgeschwindigkeiten (1)
- Massenversatzprozesse (1)
- Matching (1)
- Materialeigenschaften (1)
- Mathematics textbooks (1)
- Medien (1)
- Medienrecht (1)
- Medienwissenschaft (1)
- Meeresspiegel (1)
- Meeresspiegelanstieg (1)
- Methoden: Datenauswertung (1)
- Methoden: statistisch (1)
- Migrationsdiskurs (1)
- Mikrofluidik (1)
- Mikrokanal (1)
- Mikrosakkaden (1)
- Mikrosakkadensequenzen (1)
- Milchsäure (1)
- Mineralreaktion (1)
- Model (1)
- Modell (1)
- Modellgetrieben (1)
- Modelling (1)
- Modelltransformation (1)
- Modifikationsphase (1)
- Monsun-Unterbrechungen (1)
- Multi-Spektrum-Regularisierung (1)
- Myokardinfarkt (1)
- N-Vinylcaprolactam (1)
- N-Vinylpyrrolidon (1)
- N-vinylcaprolactame (1)
- N-vinylpyrrolidone (1)
- Nachbeben (1)
- Nachhaltigkeit (1)
- Nachhaltigkeit im ländlichen Raum (1)
- Nahrungsmittelselbstversorgung (1)
- Nahrungsmittelsicherheit (1)
- Nahrungsnetz (1)
- Nanoeisen (1)
- Naphthalimid (1)
- Neotektonik (1)
- Neue Kulturgeographie (1)
- Neuverschuldung (1)
- New Cultural Geography (1)
- Niederschlagsinterpolation (1)
- Niere (1)
- Niger (1)
- No God in Sight (1)
- O-Antigen (1)
- O-antigen (1)
- Oberfläche (1)
- Oberflächenemissivität (1)
- Oberflächenprozesse (1)
- Octopamin (1)
- Orthographie (1)
- Ostkordillere (1)
- Oxalat-Fällung (1)
- PBPK (1)
- PBTK (1)
- POCT (1)
- PPP (1)
- Paläoaltimetrie (1)
- Paläoklima (1)
- Paläotektonik (1)
- Pamir (1)
- Pather Panchali (1)
- Pathogenerkennung (1)
- Patient (1)
- Pelletbildung (1)
- Perowskit-Oxide (1)
- Phononen Dynamik (1)
- Phononen Dämpfung (1)
- Phononen Rückfaltung (1)
- Phosphat akkumulierende Organismen (1)
- Phosphatase (1)
- Phosphorylierung (1)
- Photokatalyse (1)
- Phylogenese (1)
- Phytoplankton (1)
- Pikosekundenakustik (1)
- Plasmonik (1)
- Plateau (1)
- Poland (1)
- Polen (1)
- Polnisch (1)
- Polyelektrolyte (1)
- Polymorphismus (1)
- Pontiden (1)
- Pontides (1)
- Praktikum (1)
- Presskuchen (1)
- Presssaft (1)
- Process Mining (1)
- Professionalisierung (1)
- Progressive (1)
- Projektionen (1)
- Protein (1)
- Protein-Kohlenhydrat Interaktionen (1)
- Proteine (1)
- Prozess- und Datenintegration (1)
- Prozessarchitektur (1)
- Prozessautomatisierung (1)
- Prozessregenerierung (1)
- Prozessverfeinerung (1)
- Psychiatrie (1)
- Public Corporate Governance (1)
- Public Management (1)
- Puna (1)
- QSAR (1)
- Quartiersrat (1)
- Quasare: Absorptionslinien (1)
- RNA Sequencing (1)
- RNA Sequenzierung (1)
- Rechenschaftspflicht (1)
- Reduktase (1)
- Reduktionismus (1)
- Refinanzierung (1)
- Reflexion (1)
- Reflexivpronomen (1)
- Reformen (1)
- Regulierung (1)
- Reibungskoeffizient (1)
- Reiseliteratur (1)
- Rekommunalisierung (1)
- Relativsätze (1)
- Resistance (1)
- Retrieval (1)
- Rezeptorscreening (1)
- Rheasilvia (1)
- Rheinfränkisch (1)
- Rhine Franconian (1)
- Rhodamin B (1)
- Rotliegend (1)
- Rumpfmuskelkraft (1)
- Rundfunk (1)
- Rundfunkordnung (1)
- République Démocratique Allemande (1)
- SEC (1)
- SOE (1)
- SORLA (1)
- Sakkadendetektion (1)
- Salz (1)
- Salztransport (1)
- Sanierung (1)
- Scheibengalaxien (1)
- Scheidung (1)
- Schlüsselkompetenzen (1)
- Schreibkompetenz (1)
- Schrödinger Problem (1)
- Schulbuch (1)
- Schule (1)
- Schulleiter (1)
- Schulleiterwirksamkeit (1)
- Schulleitung (1)
- Schwermetalle (1)
- Science (1)
- Sediment Fingerprinting (1)
- Sedimenttransport (1)
- Seismologie (1)
- Seismology (1)
- Selbstkongruenz (1)
- Selbstkonzept (1)
- Seltenerdelemente (1)
- Shoah (1)
- Simulationsexperimente (1)
- Situationssemantik (1)
- Social Cognition (1)
- Social-Exchange-Theorie (1)
- Software (1)
- Solvatochromie (1)
- South American Bureau of the Communist International (1)
- South Asian summer monsoon (1)
- Sozialer Einfluss (1)
- Spektroskopie (1)
- Spiralgalaxien (1)
- Sportvereinsmitgliedschaft (1)
- Sprung-Lande-Aufgaben (1)
- Stadt (1)
- Sternaktivität (1)
- Sternphysik (1)
- Steuerung (1)
- Strahlungstransport (1)
- Strukturgleichungsmodellierung (1)
- Subjektwissenschaft (1)
- Supernovaüberreste (1)
- Symbolik (1)
- Synchronisation (1)
- Südamerikanisches Büro der Kommunistischen Internationale (1)
- Südasiatischen Sommermonsun (1)
- Süßgeschmack (1)
- Süßrezeptor (1)
- Süßstoff (1)
- TTC (1)
- Tailspike (1)
- Tailspikes (1)
- Tas1r1 (1)
- Technik (1)
- Technikentwicklung (1)
- Tektonik (1)
- Telemedien (1)
- Tempus (1)
- Textbook analysis (1)
- Textbook research (1)
- The Bioscope Man (1)
- The Last Jet Engine Laugh (1)
- Thermosphäre hoher Breiten (1)
- Thiazol-Salze (1)
- Tian-Shan (1)
- Tiefendeformation (1)
- Tien-Shan (1)
- Totes Meer (1)
- Toxikokinetik (1)
- Transaktionskosten-Theorie (1)
- Transkriptomik (1)
- Transmission (1)
- Transporteraktivierung (1)
- Trendattributierung (1)
- Trennung (1)
- Tropfen (1)
- Tschadisch (1)
- Tyramin (1)
- Tätigkeiten (1)
- U-Pb Geochronologie (1)
- U-Pb geochronology (1)
- USA (1)
- USA / Politik, Zeitgeschichte, Recht (1)
- Umweltmonitoring (1)
- United States (1)
- Upper Atmosphere Model (UAM) (1)
- VIRTIS (1)
- Variabilität von Bodenbewegung (1)
- Vegetationsbedeckung (1)
- Veneneia (1)
- Venus Express (1)
- Verdunstung (1)
- Verfassung (1)
- Verfassung / Europäische Verfassung (1)
- Verlaufsform (1)
- Verletzungsprävention (1)
- Verschuldung (1)
- Versuchsanbau (1)
- Verwaltungsreformen (1)
- Vesta (1)
- Videoanalyse (1)
- Videoüberwachung (1)
- Vier-Wellen-Mischung (1)
- Viskosität (1)
- Vokalperzeption (1)
- Vokalproduktion (1)
- Warven (1)
- Wasserstoff (1)
- Waveletanalyse (1)
- Werte (1)
- Winterfischsterben (1)
- Wissenschaft (1)
- Wissenschaftspolitik (1)
- Wohngegend (1)
- Zeitreihenanalyse (1)
- Zeugenschaft (1)
- Zielsteuerung (1)
- Zooplankton (1)
- abstraction (1)
- access (1)
- accountability (1)
- acoustic fluidization (1)
- adhesion proteins (1)
- administration (1)
- administrative reforms (1)
- adult education (1)
- aerosols (1)
- afrikanische Sprachen (1)
- aftershocks (1)
- agencification (1)
- akustische Fluidisierung (1)
- alcohol (1)
- allochthoner Eintrag (1)
- allochthonous matter (1)
- analysis (1)
- angiography (1)
- anthropogener Meeresspiegel (1)
- anthropogenic sea level (1)
- applied linguistics (1)
- arctic (1)
- artificial mixtures (1)
- aspect (1)
- asset backed securities (1)
- asteroids (1)
- astrophysics (1)
- autonomy (1)
- avant-garde (1)
- bacteriophages (1)
- banking regulation (1)
- benthic food web (1)
- benthische Nahrungskette (1)
- bioactivity (1)
- biogas (1)
- biogene Amine (1)
- biogenic amines (1)
- biomechanics (1)
- biomolecule (1)
- biosensor (1)
- bistability (1)
- body weight loss (1)
- body weight maintenance (1)
- boundary-work (1)
- bpm (1)
- broadcasting (1)
- broadcasting law (1)
- budget study (1)
- business process architecture (1)
- business process management (1)
- cable transmission (1)
- calcineurin inhibitors (1)
- canonical correlation analysis (1)
- capital market (1)
- carbon nitride (1)
- carbonates (1)
- cell signaling (1)
- chemical clock (1)
- chemotaxis (1)
- ciliates (1)
- civic participation (1)
- coalescence (1)
- coastal erosion (1)
- coastal flooding (1)
- coefficient of friction (1)
- cognitive modeling (1)
- coherent phonons (1)
- colloid transport (1)
- commemorative culture (1)
- communism (1)
- communisme (1)
- comparative literature (1)
- competencies (1)
- complex model (1)
- complex networks (1)
- composites (1)
- computational model (1)
- computer science education (CSE) (1)
- concentration (1)
- conformance analysis (1)
- content-addressable memory (1)
- control (1)
- conversation analysis (1)
- coregistration (1)
- corporate governance (1)
- corporatization (1)
- corrosion (1)
- cosmic rays (1)
- cosmogenic radionuclides (1)
- cosmology: observations (1)
- cost-benefit-analysis (1)
- coupling (1)
- covered funding instruments (1)
- critical psychology (1)
- cross-scale analysis (1)
- curriculum development (1)
- curved radial ridges (1)
- data (1)
- data correctness checking (1)
- data extraction (1)
- data filtering (1)
- data objects (1)
- data states (1)
- definiteness (1)
- deforestation (1)
- deformation (1)
- demografischer Wandel (1)
- demographic change (1)
- demographic policy (1)
- denitrification (1)
- denudation processes (1)
- dependency resolution (1)
- deutsche Grenzregion zu Polen (1)
- didaktische Entwicklungsforschung (1)
- didatic development research (1)
- dietary changes (1)
- dietary patterns (1)
- difference-in-difference (1)
- discourse (1)
- division of labor (1)
- divorce (1)
- domain wall motion (1)
- drop (1)
- duration (1)
- early earth tectonics (1)
- earth's mantle (1)
- earthquake (1)
- earthquake forecasting (1)
- earthquake interaction (1)
- ecohydrology (1)
- elektroaktive Polymere (1)
- emissions (1)
- employment services (1)
- energy supply (1)
- ensemble simulations (1)
- entrepreneurship (1)
- environmental monitoring (1)
- enzyme (1)
- epithelial salt transport (1)
- equol (1)
- evaluation (1)
- evaluation of active labor market policy (1)
- evaporation (1)
- event abstraction (1)
- evidence based medicine (1)
- evolution (1)
- exhumation processes (1)
- extragalactic physics (1)
- eye tracking (1)
- family dissolution (1)
- feldlinengerichtete Ströme (1)
- fermentation experiments (1)
- fff (1)
- field aligned currents (1)
- field trials (1)
- film (1)
- finite Differenzen (1)
- finite Elemente (1)
- finite differences (1)
- finite elements (1)
- fixational eye movements (1)
- flood (1)
- flood damage (1)
- flood reconstruction (1)
- flow photolysis (1)
- fluorescence sensor (1)
- fluvial incision (1)
- fluviale Einschneidung (1)
- flux de Marangoni (1)
- focus (1)
- focus-sensitivity (1)
- fodder legumes (1)
- food demand (1)
- food security (1)
- food self-sufficiency (1)
- formal framework (1)
- formale Semantik (1)
- formales Framework (1)
- formalism (1)
- formation fluid (1)
- four-wave mixing (1)
- functionalization (1)
- galaxy evolution (1)
- galaxy formation (1)
- galaxy structure (1)
- gekrümmte radiale Bergrücken (1)
- general education in computer science (1)
- generalised nonlinear Schrödinger equation (1)
- geographic border space research (1)
- geographische Grenzraumforschung (1)
- geoinfomation science (1)
- geology (1)
- geophysics (1)
- geothermal (1)
- geovisualisation (1)
- global change (1)
- global description (1)
- globular clusters (1)
- glucagon (1)
- glycosylation (1)
- gouttes (1)
- gouttes sessiles (1)
- governance (1)
- government guarantees (1)
- granule formation (1)
- ground motion variability (1)
- ground motions (1)
- grounded theory (1)
- gut microbiota (1)
- headmaster (1)
- heavy metals (1)
- high-latitudinal thermosphere (1)
- higher education didactics (1)
- hillslope diffusion (1)
- historical earthquakes (1)
- historische Erdbeben (1)
- honey bee (1)
- household income (1)
- housing (1)
- hydrate (1)
- hydrogel (1)
- hydrogen (1)
- hydrological modeling (1)
- hydrologische Modellierung (1)
- hypersound (1)
- hypersound propagation (1)
- hyperspectral (1)
- hyporheic zone (1)
- hyporheische Zone (1)
- illiteracy (1)
- impact cratering (1)
- impact simulation (1)
- implied spectator (1)
- in silico (1)
- in-situ remediation (1)
- indisch-englischer Roman (1)
- indisches Kino (1)
- informatische Allgemeinbildung (1)
- infrared (1)
- infrastructure covered bond (1)
- infrastructure financing (1)
- injury prevention (1)
- instability (1)
- insulin-induced hypoglycemia (1)
- integrative omics analysis (1)
- interaction (1)
- interaction analysis (1)
- intergalactic medium (1)
- intergalaktisches Medium (1)
- internal variability (1)
- internship (1)
- ionic liquids (1)
- ionic polymers (1)
- ionische Flüssigkeit (1)
- ionischen Polymere (1)
- ionothermal (1)
- isoflavones (1)
- isotopes (1)
- jump-landing tasks (1)
- key competencies (1)
- kidney (1)
- kinetics (1)
- kognitive Modellierung (1)
- kohärente Phononen (1)
- kommunale Unternehmen (1)
- komplexe Netzwerke (1)
- kosmische Strahlung (1)
- kosmogene Nuklide (1)
- labor supply (1)
- lactic acid production (1)
- lake food web (1)
- land use change (1)
- landscape evolution (1)
- leaf wax (1)
- learning (1)
- leitliniengerechte Pharmakotherapie (1)
- liberalization of energy supply (1)
- liegende Tropfen (1)
- linguistics (1)
- lipopolysaccharide (1)
- literacy acquisition (1)
- livestock feed (1)
- living area (1)
- local affairs (1)
- long-term desiccation (1)
- magnetite Ketter (1)
- magnetosphere-ionosphere-thermosphere coupling (1)
- magnetotactic bacteria (1)
- magnetotaktische Bakterien (1)
- magnetotellurics (1)
- management (1)
- management autonomy (1)
- management by objectives (1)
- management routines (1)
- marital status (1)
- mass-wasting velocities (1)
- matching (1)
- material properties (1)
- media (1)
- media anthropology (1)
- media law (1)
- media studies (1)
- mentoring (1)
- methanogene Archaeen (1)
- methanogenic archaea (1)
- methods: data analysis (1)
- methods: statistical (1)
- microchannel (1)
- microsaccades (1)
- migration discourse (1)
- mineral reaction (1)
- model transformation (1)
- model tuning (1)
- model-driven (1)
- modeling (1)
- modelling (1)
- modellinterne Variabilitaet (1)
- modernization (1)
- modification stage (1)
- moist static energy (1)
- monsoon breaks (1)
- motif périodique (1)
- motorische Leistungsfähigkeit (1)
- mountain hydrology (1)
- multi-spectrum regularization (1)
- multiobjective calibration (1)
- multiobjektive Kalibrierung (1)
- multivariate statistische Technik (1)
- municipal enterprises (1)
- myocardial infarction (1)
- nanoparticle (1)
- nanoparticles (1)
- nanoparticles assembly (1)
- nanoscale zero-valent iron (nZVI) (1)
- naphthalimide (1)
- narration (1)
- natural reading (1)
- natürliches Lesen (1)
- neotectonics (1)
- neural oscillations (1)
- neuronale Oszillationen (1)
- new public management (1)
- nicht-stöchiometrische Modifikationen (1)
- non-stoichiometric modifications (1)
- nonlinear (1)
- nonverbal (1)
- numeric device simulations (1)
- numerical model (1)
- numerical modeling (1)
- numerische Bauteilsimulationen (1)
- numerische Strömungsmechanik (1)
- obesity (1)
- octopamine (1)
- onsite monitoring (1)
- optical frequency combs (1)
- optical solitons (1)
- optical spectroscopy (1)
- optische Frequenzkämme (1)
- optische Solitonen (1)
- optische Spektroskopie (1)
- optoelectronic measurements (1)
- optoelektronische Messungen (1)
- organic solar cells (1)
- organische Solarzellen (1)
- organizational changes (1)
- origin (1)
- orthography (1)
- ostafrikanisches Riftsystem (1)
- overacidification (1)
- oxalic precipitation (1)
- palaeoclimate (1)
- paleoaltimetry (1)
- panel data (1)
- paperbased (1)
- papierbasiert (1)
- participatory budget (1)
- particle-in-cell simulations (1)
- particulate organic matter (1)
- partielle Integration auf dem Pfadraum (1)
- patient (1)
- pelagische Nahrungskette (1)
- periodic pattern (1)
- periodisches Muster (1)
- perovskite oxides (1)
- pflanzliche Zellwände (1)
- phages (1)
- phenomenology (1)
- phonological awareness (1)
- phonological speech disorders (1)
- phonologische Bewusstheit (1)
- phonon backfolding (1)
- phonon damping (1)
- phonon dynamics (1)
- phosphate accumulating organisms (1)
- phosphorylation (1)
- photocatalysis (1)
- photography (1)
- phylogeny (1)
- physical fitness (1)
- picosecond acoustics (1)
- plankton (1)
- plant cell walls (1)
- plasmonics (1)
- plateau (1)
- polyelectrolyte (1)
- polymerised ionic liquids (1)
- polymorphism (1)
- population marketing (1)
- postcolonial literatures in English (1)
- postkoloniale englische Literaturen (1)
- poverty (1)
- precipitation interpolation (1)
- prediction (1)
- principal (1)
- process and data integration (1)
- process automation (1)
- process mining (1)
- process recovery (1)
- process refinement (1)
- professionalisation (1)
- programm (1)
- projections (1)
- protein-carbohydrate interactions (1)
- précipitation (1)
- précipitation oxalique (1)
- psychiatrie (1)
- psychiatry (1)
- public debt (1)
- public management (1)
- public sector covered bond (1)
- public service (1)
- public-private partnership (1)
- qualitative Sozialforschung (1)
- qualitative social research (1)
- quango (1)
- quasars: absorption lines (1)
- radiative transfer (1)
- random walks on graphs (1)
- rare earth elements (1)
- rasadhvani (1)
- rate-state friction (1)
- reactive transport groundwater model (1)
- reaktives Grundwassermodell (1)
- real estate portals (1)
- reception aesthetics (1)
- reciprocal characteristics (1)
- reductase (1)
- reductionism (1)
- refinancing (1)
- reflection (1)
- reflexives (1)
- regional aspects (1)
- regionale Versorgung (1)
- regionales Klimamodell (1)
- regression methods (1)
- regressive Sakkaden (1)
- regressive saccades (1)
- relative clauses (1)
- remote sensing (1)
- remote sensing data (1)
- remunicipalising (1)
- response spectra (1)
- retrieval (1)
- reziproke Invarianten (1)
- reziproke Klassen (1)
- rhodamine b (1)
- räumliche Immobilienmarktanalyse (1)
- saccade detection (1)
- salt (1)
- school (1)
- school effectiveness (1)
- school management (1)
- school-aged children (1)
- science policy (1)
- sea level (1)
- sea-level rise (1)
- sediment fingerprinting (1)
- sediment transport (1)
- seismic hazard (1)
- seismic risk (1)
- seismisches Risiko (1)
- sel (1)
- selbstorganisierte Karten (1)
- self-organising maps (1)
- seltene Erden (1)
- semi-empirical models (1)
- semiempirische Modelle (1)
- separation (1)
- sequences of microsaccades (1)
- sessile droplet (1)
- simulation experiments (1)
- situation semantics (1)
- skalenübergreifende Analyse (1)
- social exchange theory (1)
- socioeconomic status (1)
- soil (1)
- soil organic carbon (1)
- solar wind and interplanetary magnetic field influence (1)
- solvatochrome (1)
- sozioökonomischer Status (1)
- spatial analysis (1)
- specific speech and language impairments (SLI) (1)
- spectrograph calibration (1)
- spectroscopy (1)
- sports club participation (1)
- stable isotopes (1)
- start-up subsidies (1)
- state owned enterprises (1)
- statistical seismology (1)
- statistische Seismologie (1)
- steering (1)
- stellar activity (1)
- stellar physics (1)
- stellar populations (1)
- stellare Populationen (1)
- streambed morphology (1)
- student teachers (1)
- subduction-accretionary complexes (1)
- subduktions-akkretions Komplexe (1)
- superlattice dispersion (1)
- supernova remnants (1)
- surface (1)
- surface emissivity (1)
- surface evolution (1)
- surface processes (1)
- suspended sediment (1)
- sustainability (1)
- suture (1)
- sweet taste (1)
- sweet taste receptor (1)
- sweetener (1)
- synchronization (1)
- syntactic expectation (1)
- syntax (1)
- tasks (1)
- taste receptor (1)
- taste receptor screening (1)
- technology (1)
- technology development (1)
- tectonics (1)
- tense (1)
- testimony (1)
- theoretical and practical foundation of german didactics (1)
- theoretische und empirische Fundierung der Fachdidaktik Deutsch (1)
- theory practice (1)
- thermo-mechanics (1)
- thermochemical mantle convection (1)
- thermochemischer Mantelkonvektion (1)
- thermochronology (1)
- thermoresponsiv (1)
- thiazolium (1)
- thick ascending limb (1)
- time resolved (1)
- time series analysis (1)
- toxicology (1)
- transaction cost theory (1)
- transcriptomics (1)
- transformative learning (1)
- transformatives Lernen (1)
- transient earthquake patterns (1)
- transient methods (1)
- transiente Erdbebenmuster (1)
- transiente Messmethoden (1)
- travel literature (1)
- trend attribution (1)
- trophic transfer efficiency (1)
- trophische Transfereffizienz (1)
- trunk muscle strength (1)
- tyramine (1)
- umami (1)
- umschriebene Sprachentwicklungsstörungen (1)
- uncertainty estimation (1)
- upper atmosphere model (1)
- varves (1)
- vegetation cover (1)
- verallgemeinerte nichlineare Schrödinger Gleichung (1)
- video analysis (1)
- video surveillance (1)
- viscosity (1)
- visual culture (1)
- visual textures (1)
- volcanic glass (1)
- vowel perception (1)
- vowel production (1)
- vulkanischer Gläser (1)
- wavelet analysis (1)
- winter fish kill (1)
- written language acquisition (1)
- written literacy (1)
- yield gap (1)
- zeitaufgelöst (1)
- Ökohydrologie (1)
- Ökosystem (1)
- Übereinstimmungsanalyse (1)
- Übergitter Dispersion (1)
- Übersäuerung (1)
- Übertragung (1)
- ß-Cyclodextrin (1)
- ß-cyclodextrine (1)
- öffentliche Unternehmen (1)
- öffentliche Verschuldung (1)
Institut
- Institut für Biochemie und Biologie (48)
- Institut für Geowissenschaften (33)
- Institut für Physik und Astronomie (28)
- Institut für Ernährungswissenschaft (19)
- Institut für Chemie (17)
- Wirtschaftswissenschaften (17)
- Sozialwissenschaften (15)
- Bürgerliches Recht (13)
- Department Linguistik (9)
- Öffentliches Recht (9)
- Department Erziehungswissenschaft (7)
- Institut für Mathematik (7)
- Institut für Umweltwissenschaften und Geographie (7)
- Department Psychologie (6)
- Historisches Institut (6)
- Institut für Germanistik (6)
- Institut für Informatik und Computational Science (6)
- Institut für Romanistik (6)
- Institut für Künste und Medien (5)
- Institut für Anglistik und Amerikanistik (4)
- Department Sport- und Gesundheitswissenschaften (3)
- Hasso-Plattner-Institut für Digital Engineering gGmbH (3)
- Strafrecht (3)
- Strukturbereich Kognitionswissenschaften (3)
- Extern (2)
- Department Grundschulpädagogik (1)
- Department Musik und Kunst (1)
- Institut für Philosophie (1)
- Institut für Religionswissenschaft (1)
- Juristische Fakultät (1)
- Klassische Philologie (1)
- Strukturbereich Bildungswissenschaften (1)
Die Phyllosphäre
(2015)
Analysis and modeling of transient earthquake patterns and their dependence on local stress regimes
(2015)
Investigations in the field of earthquake triggering and associated interactions, which includes aftershock triggering as well as induced seismicity, is important for seismic hazard assessment due to earthquakes destructive power. One of the approaches to study earthquake triggering and their interactions is the use of statistical earthquake models, which are based on knowledge of the basic seismicity properties, in particular, the magnitude distribution and spatiotemporal properties of the triggered events.
In my PhD thesis I focus on some specific aspects of aftershock properties, namely, the relative seismic moment release of the aftershocks with respect to the mainshocks; the spatial correlation between aftershock occurrence and fault deformation; and on the influence of aseismic transients on the aftershock parameter estimation. For the analysis of aftershock sequences I choose a statistical approach, in particular, the well known Epidemic Type Aftershock Sequence (ETAS) model, which accounts for the input of background and triggered seismicity. For my specific purposes, I develop two ETAS model modifications in collaboration with Sebastian Hainzl. By means of this approach, I estimate the statistical aftershock parameters and performed simulations of aftershock sequences as well.
In the case of seismic moment release of aftershocks, I focus on the ratio of cumulative seismic moment release with respect to the mainshocks. Specifically, I investigate the ratio with respect to the focal mechanism of the mainshock and estimate an effective magnitude, which represents the cumulative aftershock energy (similar to Bath's law, which defines the average difference between mainshock and the largest aftershock magnitudes). Furthermore, I compare the observed seismic moment ratios with the results of the ETAS simulations. In particular, I test a restricted ETAS (RETAS) model which is based on results of a clock advanced model and static stress triggering.
To analyze spatial variations of triggering parameters I focus in my second approach on the aftershock occurrence triggered by large mainshocks and the study of the aftershock parameter distribution and their spatial correlation with the coseismic/postseismic slip and interseismic locking. To invert the aftershock parameters I improve the modified ETAS (m-ETAS) model, which is able to take the extension of the mainshock rupture into account. I compare the results obtained by the classical approach with the output of the m-ETAS model.
My third approach is concerned with the temporal clustering of seismicity, which might not only be related to earthquake-earthquake interactions, but also to a time-dependent background rate, potentially biasing the parameter estimations. Thus, my coauthors and I also applied a modification of the ETAS model, which is able to take into account time-dependent background activity. It can be applicable for two different cases: when an aftershock catalog has a temporal incompleteness or when the background seismicity rate changes with time, due to presence of aseismic forces.
An essential part of any research is the testing of the developed models using observational data sets, which are appropriate for the particular study case. Therefore, in the case of seismic moment release I use the global seismicity catalog. For the spatial distribution of triggering parameters I exploit two aftershock sequences of the Mw8.8 2010 Maule (Chile) and Mw 9.0 2011 Tohoku (Japan) mainshocks. In addition, I use published geodetic slip models of different authors. To test our ability to detect aseismic transients my coauthors and I use the data sets from Western Bohemia (Central Europe) and California.
Our results indicate that:
(1) the seismic moment of aftershocks with respect to mainshocks depends on the static stress changes and is maximal for the normal, intermediate for thrust and minimal for strike-slip stress regimes, where the RETAS model shows a good correspondence with the results;
(2) The spatial distribution of aftershock parameters, obtained by the m-ETAS model, shows anomalous values in areas of reactivated crustal fault systems. In addition, the aftershock density is found to be correlated with coseismic slip gradient, afterslip, interseismic coupling and b-values. Aftershock seismic moment is positively correlated with the areas of maximum coseismic slip and interseismically locked areas. These correlations might be related to the stress level or to material properties variations in space;
(3) Ignoring aseismic transient forcing or temporal catalog incompleteness can lead to the significant under- or overestimation of the underlying trigger parameters. In the case when a catalog is complete, this method helps to identify aseismic sources.
In many procedures of seismic risk mitigation, ground motion simulations are needed to test systems or improve their effectiveness. For example they may be used to estimate the level of ground shaking caused by future earthquakes. Good physical models for ground motion simulation are also thought to be important for hazard assessment, as they could close gaps in the existing datasets. Since the observed ground motion in nature shows a certain variability, part of which cannot be explained by macroscopic parameters such as magnitude or position of an earthquake, it would be desirable that a good physical model is not only able to produce one single seismogram, but also to reveal this natural variability.
In this thesis, I develop a method to model realistic ground motions in a way that is computationally simple to handle, permitting multiple scenario simulations. I focus on two aspects of ground motion modelling. First, I use deterministic wave propagation for the whole frequency range – from static deformation to approximately 10 Hz – but account for source variability by implementing self-similar slip distributions and rough fault interfaces. Second, I scale the source spectrum so that the modelled waveforms represent the correct radiated seismic energy. With this scaling I verify whether the energy magnitude is suitable as an explanatory variable, which characterises the amount of energy radiated at high frequencies – the advantage of the energy magnitude being that it can be deduced from observations, even in real-time.
Applications of the developed method for the 2008 Wenchuan (China) earthquake, the 2003 Tokachi-Oki (Japan) earthquake and the 1994 Northridge (California, USA) earthquake show that the fine source discretisations combined with the small scale source variability ensure that high frequencies are satisfactorily introduced, justifying the deterministic wave propagation approach even at high frequencies. I demonstrate that the energy magnitude can be used to calibrate the high-frequency content in ground motion simulations.
Because deterministic wave propagation is applied to the whole frequency range, the simulation method permits the quantification of the variability in ground motion due to parametric uncertainties in the source description. A large number of scenario simulations for an M=6 earthquake show that the roughness of the source as well as the distribution of fault dislocations have a minor effect on the simulated variability by diminishing directivity effects, while hypocenter location and rupture velocity more strongly influence the variability. The uncertainty in energy magnitude, however, leads to the largest differences of ground motion amplitude between different events, resulting in a variability which is larger than the one observed.
For the presented approach, this dissertation shows (i) the verification of the computational correctness of the code, (ii) the ability to reproduce observed ground motions and (iii) the validation of the simulated ground motion variability. Those three steps are essential to evaluate the suitability of the method for means of seismic risk mitigation.
Methicillin resistant Staphylococcus aureus (MRSA) is one of the most important antibiotic-resistant pathogens in hospitals and the community. Recently, a new generation of MRSA, the so called livestock associated (LA) MRSA, has emerged occupying food producing animals as a new niche. LA-MRSA can be regularly isolated from economically important live-stock species including corresponding meats. The present thesis takes a methodological approach to confirm the hypothesis that LA-MRSA are transmitted along the pork, poultry and beef production chain from animals at farm to meat on consumers` table. Therefore two new concepts were developed, adapted to differing data sets.
A mathematical model of the pig slaughter process was developed which simulates the change in MRSA carcass prevalence during slaughter with special emphasis on identifying critical process steps for MRSA transmission. Based on prevalences as sole input variables the model framework is able to estimate the average value range of both the MRSA elimination and contamination rate of each of the slaughter steps. These rates are then used to set up a Monte Carlo simulation of the slaughter process chain. The model concludes that regardless of the initial extent of MRSA contamination low outcome prevalences ranging between 0.15 and 1.15 % can be achieved among carcasses at the end of slaughter. Thus, the model demonstrates that the standard procedure of pig slaughtering in principle includes process steps with the capacity to limit MRSA cross contamination. Scalding and singeing were identified as critical process steps for a significant reduction of superficial MRSA contamination.
In the course of the German national monitoring program for zoonotic agents MRSA prevalence and typing data are regularly collected covering the key steps of different food production chains. A new statistical approach has been proposed for analyzing this cross sectional set of MRSA data with regard to show potential farm to fork transmission. For this purpose, chi squared statistics was combined with the calculation of the Czekanowski similarity index to compare the distributions of strain specific characteristics between the samples from farm, carcasses after slaughter and meat at retail. The method was implemented on the turkey and veal production chains and the consistently high degrees of similarity which have been revealed between all sample pairs indicate MRSA transmission along the chain.
As the proposed methods are not specific to process chains or pathogens they offer a broad field of application and extend the spectrum of methods for bacterial transmission assessment.
In den letzten Jahrzehnten ist der Trend der Verselbstständigung in vielen Kommunen zu beobachten. Ein Großteil der öffentlichen Leistungserbringer wird mittlerweile als privatrechtliche Gesellschaften in einem wettbewerbsorientierten Umfeld geführt. Während viele Forscher Ausgliederungen in Form von nachgeordneten Behörden auf Bundesebene untersuchen und diese Reformwelle als einen faktischen Autonomisierungsprozess beschreiben, gibt es nur einige wenige Studien, die sich explizit mit den Autonomisierungstendenzen auf Kommunalebene auseinandersetzen. Daher fehlt es an empirischen Erkenntnissen zur Steuerung der kommunalen Beteiligungen.
In dieser Arbeit werden die Steuerungsarrangements deutscher Großstädte erstmals aus Sicht der Gesteuerten beleuchtet. Das Untersuchungsziel der vorliegenden Forschungsarbeit besteht darin, Flexibilisierungstendenzen in mehrheitlich kommunalen Unternehmen zu identifizieren und hierfür Erklärungsfaktoren zu identifizieren. Die Forschungsfrage lautet: Welche instrumentellen und relationalen Faktoren beeinflussen die Managementautonomie in kommunalen Mehrheitsbeteiligungen?
Dabei interessiert insbesondere die Einflussnahme der Kommunen auf verschiedene Tätigkeitsbereiche ihrer Ausgliederungen. Über diese unternehmensspezifischen Sachverhalte ist in Deutschland fast nichts und international nur sehr wenig Empirisches bekannt. Zur Beantwortung der Forschungsfrage hat der Autor auf Basis der Transaktionskosten- und der Social-Exchange-Theorie einen Analyserahmen erstellt. Die aufgestellten Hypothesen wurden mit einer großflächigen Umfrage bei 243 Unternehmen in den 39 größten deutschen Städten empirisch getestet.
Im Ergebnis zeigen sich mehrere empirische Erkenntnisse: Erstens konnten mittels Faktorenanalyse vier unabhängige Faktoren von Managementautonomie in kommunalen Unternehmen identifiziert werden: Personalautonomie, Generelles Management, Preisautonomie und Strategische Fragen. Während die Kommunen ihren Beteiligungen einen hohen Grad an Personalautonomie zugestehen, unterliegen vor allem strategische Investitionsentscheidungen wie die finanzielle Beteiligung an Tochterfirmen, große Projektvorhaben, Diversifikationsentscheidungen oder Kreditautfnahmen einem starken politischen Einfluss.
Zweitens führt eine Rechtsformänderung und die Platzierung in einem Wettbewerbsumfeld (auch bekannt als Corporatisation) vor allem zu einer größeren Flexibilisierung der Personal- und Preispolitik, wirkt sich allerdings wenig auf die weiteren Faktoren der Managementautonomie, Generelles Management und Strategische Entscheidungen, aus. Somit behalten die Kommunen ihre Möglichkeit, auf wichtige Unternehmensfragen der Beteiligung Einfluss zu nehmen, auch im Fall einer Formalprivatisierung bei.
Letztlich können zur Erklärung der Autonomiefaktoren transaktionskostenbasierte und relationale Faktoren ergänzend herangezogen werden. In den Transaktionsspezifika wirken vor allem der wahrgenommene Wettbewerb in der Branche, die Messbarkeit der Leistung, Branchenvariablen, die Anzahl der Politiker im Aufsichtsrat und die eingesetzten Steuerungsmechanismen. In den relationalen Faktoren setzen sich die Variablen gegenseitiges Vertrauen, Effektivität der Aufsichtsräte, Informationsaustausch, Rollenkonflikte, Rollenambivalenzen und Geschäftsführererfahrung im Sektor durch.
Ni-based materials for the catalytic conversion of lignocellulosic biomass into valuable products
(2015)
The rise of evolutionary novelties is one of the major drivers of evolutionary diversification. African weakly-electric fishes (Teleostei, Mormyridae) have undergone an outstanding adaptive radiation, putatively owing to their ability to communicate through species-specific Electric Organ Discharges (EODs) produced by a novel, muscle-derived electric organ. Indeed, such EODs might have acted as effective pre-zygotic isolation mechanisms, hence favoring ecological speciation in this group of fishes. Despite the evolutionary importance of this organ, genetic investigations regarding its origin and function have remained limited.
The ultimate aim of this study is to better understand the genetic basis of EOD production by exploring the transcriptomic profiles of the electric organ and of its ancestral counterpart, the skeletal muscle, in the genus Campylomormyrus. After having established a set of reference transcriptomes using “Next-Generation Sequencing” (NGS) technologies, I performed in silico analyses of differential expression, in order to identify sets of genes that might be responsible for the functional differences observed between these two kinds of tissues. The results of such analyses indicate that: i) the loss of contractile activity and the decoupling of the excitation-contraction processes are reflected by the down-regulation of the corresponding genes in the electric organ; ii) the metabolic activity of the electric organ might be specialized towards the production and turnover of membrane structures; iii) several ion channels are highly expressed in the electric organ in order to increase excitability, and iv) several myogenic factors might be down-regulated by transcription repressors in the EO.
A secondary task of this study is to improve the genus level phylogeny of Campylomormyrus by applying new methods of inference based on the multispecies coalescent model, in order to reduce the conflict among gene trees and to reconstruct a phylogenetic tree as closest as possible to the actual species-tree. By using 1 mitochondrial and 4 nuclear markers, I was able to resolve the phylogenetic relationships among most of the currently described Campylomormyrus species. Additionally, I applied several coalescent-based species delimitation methods, in order to test the hypothesis that putatively cryptic species, which are distinguishable only from their EOD, belong to independently evolving lineages. The results of this analysis were additionally validated by investigating patterns of diversification at 16 microsatellite loci. The results suggest the presence of a new, yet undescribed species of Campylomormyrus.
This thesis investigates temporal and aspectual reference in the typologically unrelated African languages Hausa (Chadic, Afro–Asiatic) and Medumba (Grassfields Bantu).
It argues that Hausa is a genuinely tenseless language and compares the interpretation of temporally unmarked sentences in Hausa to that of morphologically tenseless sentences in Medumba, where tense marking is optional and graded.
The empirical behavior of the optional temporal morphemes in Medumba motivates an analysis as existential quantifiers over times and thus provides new evidence suggesting that languages vary in whether their (past) tense is pronominal or quantificational (see also Sharvit 2014).
The thesis proposes for both Hausa and Medumba that the alleged future tense marker is a modal element that obligatorily combines with a prospective future shifter (which is covert in Medumba). Cross-linguistic variation in whether or not a future marker is compatible with non-future interpretation is proposed to be predictable from the aspectual architecture of the given language.
Faseroptische Spektroskopie mit hochfrequent modulierten Diodenlasern zur Analyse kleinster Volumina
(2015)
Reconstructing climate from the Dead Sea sediment record using high-resolution micro-facies analyses
(2015)
The sedimentary record of the Dead Sea is a key archive for reconstructing climate in the eastern Mediterranean region, as it stores the environmental and tectonic history of the Levant for the entire Quaternary. Moreover, the lake is located at the boundary between Mediterranean sub-humid to semi-arid and Saharo-Arabian hyper-arid climates, so that even small shifts in atmospheric circulation are sensitively recorded in the sediments. This DFG-funded doctoral project was carried out within the ICDP Dead Sea Deep Drilling Project (DSDDP) that intended to gain the first long, continuous and high-resolution sediment core from the deep Dead Sea basin. The drilling campaign was performed in winter 2010-11 and more than 700 m of sediments were recovered. The main aim of this thesis was (1) to establish the lithostratigraphic framework for the ~455 m long sediment core from the deep Dead Sea basin and (2) to apply high-resolution micro-facies analyses for reconstructing and better understanding climate variability from the Dead Sea sediments.
Addressing the first aim, the sedimentary facies of the ~455 m long deep-basin core 5017-1 were described in great detail and characterised through continuous overview-XRF element scanning and magnetic susceptibility measurements. Three facies groups were classified: (1) the marl facies group, (2) the halite facies group and (3) a group involving different expressions of massive, graded and slumped deposits including coarse clastic detritus. Core 5017-1 encompasses a succession of four main lithological units. Based on first radiocarbon and U-Th ages and correlation of these units to on-shore stratigraphic sections, the record comprises the last ca 220 ka, i.e. the upper part of the Amora Formation (parts of or entire penultimate interglacial and glacial), the last interglacial Samra Fm. (~135-75 ka), the last glacial Lisan Fm. (~75-14 ka) and the Holocene Ze’elim Formation. A major advancement of this record is that, for the first time, also transitional intervals were recovered that are missing in the exposed formations and that can now be studied in great detail.
Micro-facies analyses involve a combination of high-resolution microscopic thin section analysis and µXRF element scanning supported by magnetic susceptibility measurements. This approach allows identifying and characterising micro-facies types, detecting event layers and reconstructing past climate variability with up to seasonal resolution, given that the analysed sediments are annually laminated. Within this thesis, micro-facies analyses, supported by further sedimentological and geochemical analyses (grain size, X-ray diffraction, total organic carbon and calcium carbonate contents) and palynology, were applied for two time intervals:
(1) The early last glacial period ~117-75 ka was investigated focusing on millennial-scale hydroclimatic variations and lake level changes recorded in the sediments. Thereby, distinguishing six different micro-facies types with distinct geochemical and sedimentological characteristics allowed estimating relative lake level and water balance changes of the lake. Comparison of the results to other records in the Mediterranean region suggests a close link of the hydroclimate in the Levant to North Atlantic and Mediterranean climates during the time of the build-up of Northern hemisphere ice sheets during the early last glacial period.
(2) A mostly annually laminated late Holocene section (~3700-1700 cal yr BP) was analysed in unprecedented detail through a multi-proxy, inter-site correlation approach of a shallow-water core (DSEn) and its deep-basin counterpart (5017-1). Within this study, a ca 1500 years comprising time series of erosion and dust deposition events was established and anchored to the absolute time-scale through 14C dating and age modelling. A particular focus of this study was the characterisation of two dry periods, from ~3500 to 3300 and from ~3000 to 2400 cal yr BP, respectively. Thereby, a major outcome was the coincidence of the latter dry period with a period of moist and cold climate in Europe related to a Grand Solar Minimum around 2800 cal yr BP and an increase in flood events despite overall dry conditions in the Dead Sea region during that time. These contrasting climate signatures in Europe and at the Dead Sea were likely linked through complex teleconnections of atmospheric circulation, causing a change in synoptic weather patterns in the eastern Mediterranean.
In summary, within this doctorate the lithostratigraphic framework of a unique long sediment core from the deep Dead Sea basin is established, which serves as a base for any further high-resolution investigations on this core. It is demonstrated in two case studies that micro-facies analyses are an invaluable tool to understand the depositional processes in the Dead Sea and to decipher past climate variability in the Levant on millennial to seasonal time-scales. Hence, this work adds important knowledge helping to establish the deep Dead Sea record as a key climate archive of supra-regional significance.
Hintergrund: In Deutschland stellt der akute Myokardinfarkt (MI) eine der häufigsten Todesursachen dar. Als Ursache für regionale Unterschiede bei den Mortalitätsraten werden divergente Versorgungsstrukturen vermutet. Ziel der Untersuchung war, diese Fragestellung anhand anonymisierter krankenkassenbasierter Abrechnungsdaten zu evaluieren.
Methodik: Standardisierte Hospitalisierungs- sowie Krankenhaus- und Ein-Jahres-Mortalitätsraten nach MI wurden anhand anonymisierter Versichertendaten einer gesetzlichen Krankenkasse für das Jahr 2012 und die Bundesländer Berlin, Brandenburg und Mecklenburg-Vorpommern ermittelt (n=1.387.084, 46.3% male, 60.9 ± 18,2 years). Weiterhin wurden prädiktive Einflussfaktoren auf die Ein-Jahres-Mortalität, auf die Durchführung invasiver Prozeduren und auf eine leitliniengerechte pharmakotherapeutische Sekundärprävention analysiert.
Ergebnisse: 6.733 Patienten (73,7 ±13,0 Jahre, 56,7% männlich) wurden identifiziert. Obwohl für das Bundesland Berlin eine höhere Hospitalisierungsrate als in Mecklenburg-Vorpommern ermittelt werden konnte, ließen sich bei der Krankenhaus- und 1-Jahres-Mortalität keine signifikant abweichenden Raten zwischen den Bundesländern beobachten. Die Durchführung einer Koronarangiographie (OR: 0,42 [0,35-0,51]) und eine leitliniengerechte Pharmakotherapie (OR: 0,14 [0,12-0,17] waren mit einer geringeren 1-Jahres-Mortalität assoziiert. Die Durchführung einer Koronarangiographie und eine leitliniengerechte Pharmakotherapie von Patienten nach Myokardinfarkt wurde hingegen primär durch Alter und Geschlecht, nicht aber durch das Bundesland determiniert.
Folgerung: Eine regional divergierende stationäre und postinfarzielle Versorgung auf Bundesland-Ebene kann anhand der vorliegenden Daten nicht nachgewiesen werden.
Die vorliegende Dissertation analysiert die Mentalitäten der bürgerlichen Bewohner Bogotas 19. Jahrhundert. Einblicke in die Fremd- und Eigenperspektiven der Bogotaner werden durch die Analyse von Reiseliteratur gewonnen. Methodologisch stützt sich die Arbeit auf den Vergleich zwischen europäischen Reiseberichten aus dem 19. Jh., Chroniken aus dem 16. Jh. sowie zwei kolumbianische Romane aus dem frühen 20.. Jh. Die Texte werden historiographisch behandelt; obwohl sie unterschiedlichen literarischen Genres angehören, weisen sie einen gemeinsamen autobiographischen Charakter auf. Aus den Erfahrungen und Gedanken der Reisenden werden v.a. die Auswirkungen der geographischen und sozialen Isolation thematisiert, sowie die Einflüsse von politischen und religiösen Diskursen auf die Bildung von bürgerlichem Gedankengut.
Serious games in andragogy
(2015)
The non-linear behaviour of the atmospheric dynamics is not well understood and makes the evaluation and usage of regional climate models (RCMs) difficult. Due to these non-linearities, chaos and internal variability (IV) within the RCMs are induced, leading to a sensitivity of RCMs to their initial conditions (IC). The IV is the ability of RCMs to realise different solutions of simulations that differ in their IC, but have the same lower and lateral boundary conditions (LBC), hence can be defined as the across-member spread between the ensemble members.
For the investigation of the IV and the dynamical and diabatic contributions generating the IV four ensembles of RCM simulations are performed with the atmospheric regional model HIRHAM5. The integration area is the Arctic and each ensemble consists of 20 members. The ensembles cover the time period from July to September for the years 2006, 2007, 2009 and 2012. The ensemble members have the same LBC and differ in their IC only. The different IC are arranged by an initialisation time that shifts successively by six hours. Within each ensemble the first simulation starts on 1st July at 00 UTC and the last simulation starts on 5th July at 18 UTC and each simulation runs until 30th September. The analysed time period ranges from 6th July to 30th September, the time period that is covered by all ensemble members. The model runs without any nudging to allow a free development of each simulation to get the full internal variability within the HIRHAM5.
As a measure of the model generated IV, the across-member standard deviation and the across-member variance is used and the dynamical and diabatic processes influencing the IV are estimated by applying a diagnostic budget study for the IV tendency of the potential temperature developed by Nikiema and Laprise [2010] and Nikiema and Laprise [2011]. The diagnostic budget study is based on the first law of thermodynamics for potential temperature and the mass-continuity equation. The resulting budget equation reveals seven contributions to the potential temperature IV tendency.
As a first study, this work analyses the IV within the HIRHAM5. Therefore, atmospheric circulation parameters and the potential temperature for all four ensemble years are investigated. Similar to previous studies, the IV fluctuates strongly in time. Further, due to the fact that all ensemble members are forced with the same LBC, the IV depends on the vertical level within the troposphere, with high values in the lower troposphere and at 500 hPa and low values in the upper troposphere and at the surface. By the same reason, the spatial distribution shows low values of IV at the boundaries of the model domain.
The diagnostic budget study for the IV tendency of potential temperature reveals that the seven contributions fluctuate in time like the IV. However, the individual terms reach different absolute magnitudes. The budget study identifies the horizontal and vertical ‘baroclinic’ terms as the main contributors to the IV tendency, with the horizontal ‘baroclinic’ term producing and the vertical ‘baroclinic’ term reducing the IV. The other terms fluctuate around zero, because they are small in general or are balanced due to the domain average.
The comparison of the results obtained for the four different ensembles (summers 2006, 2007, 2009 and 2012) reveals that on average the findings for each ensemble are quite similar concerning the magnitude and the general pattern of IV and its contributions. However, near the surface a weaker IV is produced with decreasing sea ice extent. This is caused by a smaller impact of the horizontal 'baroclinic' term over some regions and by the changing diabatic processes, particularly a more intense reducing tendency of the IV due to condensative heating. However, it has to be emphasised that the behaviour of the IV and its dynamical and diabatic contributions are influenced mainly by complex atmospheric feedbacks and large-scale processes and not by the sea ice distribution.
Additionally, a comparison with a second RCM covering the Arctic and using the same LBCs and IC is performed. For both models very similar results concerning the IV and its dynamical and diabatic contributions are found. Hence, this investigation leads to the conclusion that the IV is a natural phenomenon and is independent from the applied RCM.
The main goal of this cumulative thesis is the derivation of surface emissivity data in the infrared from radiance measurements of Venus. Since these data are diagnostic of the chemical composition and grain size of the surface material, they can help to improve knowledge of the planet’s geology. Spectrally resolved images of nightside emissions in the range 1.0-5.1 μm were recently acquired by the InfraRed Mapping channel of the Visible and InfraRed Thermal Imaging Spectrometer (VIRTIS-M-IR) aboard ESA’s Venus EXpress (VEX). Surface and deep atmospheric thermal emissions in this spectral range are strongly obscured by the extremely opaque atmosphere, but three narrow spectral windows at 1.02, 1.10, and 1.18 μm allow the sounding of the surface. Additional windows between 1.3 and 2.6 μm provide information on atmospheric parameters that is required to interpret the surface signals. Quantitative data on surface and atmosphere can be retrieved from the measured spectra by comparing them to simulated spectra. A numerical radiative transfer model is used in this work to simulate the observable radiation as a function of atmospheric, surface, and instrumental parameters. It is a line-by-line model taking into account thermal emissions by surface and atmosphere as well as absorption and multiple scattering by gases and clouds. The VIRTIS-M-IR measurements are first preprocessed to obtain an optimal data basis for the subsequent steps. In this process, a detailed detector responsivity analysis enables the optimization of the data consistency. The measurement data have a relatively low spectral information content, and different parameter vectors can describe the same measured spectrum equally well. A usual method to regularize the retrieval of the wanted parameters from a measured spectrum is to take into account a priori mean values and standard deviations of the parameters to be retrieved. This decreases the probability to obtain unreasonable parameter values. The multi-spectrum retrieval algorithm MSR is developed to additionally consider physically realistic spatial and temporal a priori correlations between retrieval parameters describing different measurements. Neglecting geologic activity, MSR also allows the retrieval of an emissivity map as a parameter vector that is common to several spectrally resolved images that cover the same surface target. Even applying MSR, it is difficult to obtain reliable emissivity maps in absolute values. A detailed retrieval error analysis based on synthetic spectra reveals that this is mainly due to interferences from parameters that cannot be derived from the spectra themselves, but that have to be set to assumed values to enable the radiative transfer simulations. The MSR retrieval of emissivity maps relative to a fixed emissivity is shown to effectively avoid most emissivity retrieval errors. Relative emissivity maps at 1.02, 1.10, and 1.18 μm are finally derived from many VIRTIS-M-IR measurements that cover a surface target at Themis Regio. They are interpreted as spatial variations relative to an assumed emissivity mean of the target. It is verified that the maps are largely independent of the choice of many interfering parameters as well as the utilized measurement data set. These are the first Venus IR emissivity data maps based on a consistent application of a full radiative transfer simulation and a retrieval algorithm that respects a priori information. The maps are sufficiently reliable for future geologic interpretations.
Ehrensache Satire
(2015)
Satirische Äußerungen und Darstellungen sind weit verbreitet und geben immer wieder zu – leider nicht nur rechtlichen – Auseinandersetzungen Anlass. Durch den seit Jahren schwelenden sogenannten „Karikaturenstreit“, gipfelnd in den Anschlägen von Paris Anfang 2015, hat die Thematik eine geradezu dramatische Brisanz erlangt. Neben dem religiösen Bekenntnis ist klassischer Stein des Anstoßes aber immer noch die Ehre.
Die Untersuchung beleuchtet kritisch die Handhabung des Satirebegriffs in Rechtsprechung und juristischer Literatur und überprüft nach einer wesensgerechten Bestimmung des Satirischen, insbesondere unter Heranziehung der literaturwissenschaftlichen Beurteilung und der Einschätzung der Satiriker selbst, dem dreistufigen Deliktsaufbau folgend und anhand anschaulicher Beispiele, ob und unter welchen Voraussetzungen eine Strafbarkeit durch satirische Ehrbeeinträchtigungen in Betracht kommen kann. Besondere Bedeutung erfährt in diesem Zusammenhang die Frage nach der Einschlägigkeit der Meinungs- oder Kunstfreiheit und deren Einordnung in die strafrechtliche Prüfung sowie die eines möglichen Unrechts- oder Schuldausschlusses unter Berücksichtigung der spezifischen Funktion, welche insbesondere die politische Satire innerhalb der Gesellschaft wahrnimmt.
The Brazilian Cerrado is recognised as one of the most threatened biomes in the world, as the region has experienced a striking change from natural vegetation to intense cash crop production. The impacts of rapid agricultural expansion on soil and water resources are still poorly understood in the region. Therefore, the overall aim of the thesis is to improve our understanding of the ecohydrological processes causing water and soil degradation in the Brazilian Cerrado.
I first present a metaanalysis to provide quantitative evidence and identifying the main impacts of soil and water alterations resulting from land use change. Second, field studies were conducted to (i) examine the effects of land use change on soils of natural cerrado transformed to common croplands and pasture and (ii) indicate how agricultural production affects water quality across a meso-scale catchment. Third, the ecohydrological process-based model SWAT was tested with simple scenario analyses to gain insight into the impacts of land use and climate change on the water cycling in the upper São Lourenço catchment which experienced decreasing discharges in the last 40 years.
Soil and water quality parameters from different land uses were extracted from 89 soil and 18 water studies in different regions across the Cerrado. Significant effects on pH, bulk density and available P and K for croplands and less-pronounced effects on pastures were evident. Soil total N did not differ between land uses because most of the cropland sites were N-fixing soybean cultivations, which are not artificially fertilized with N. By contrast, water quality studies showed N enrichment in agricultural catchments, indicating fertilizer impacts and potential susceptibility to eutrophication. Regardless of the land use, P is widely absent because of the high-fixing capacities of deeply weathered soils and the filtering capacity of riparian vegetation. Pesticides, however, were consistently detected throughout the entire aquatic system. In several case studies, extremely high-peak concentrations exceeded Brazilian and EU water quality limits, which pose serious health risks.
My field study revealed that land conversion caused a significant reduction in infiltration rates near the soil surface of pasture (–96 %) and croplands (–90 % to –93 %). Soil aggregate stability was significantly reduced in croplands than in cerrado and pasture. Soybean crops had extremely high extractable P (80 mg kg–1), whereas pasture N levels declined. A snapshot water sampling showed strong seasonality in water quality parameters. Higher temperature, oxi-reduction potential (ORP), NO2–, and very low oxygen concentrations (<5 mg•l–1) and saturation (<60 %) were recorded during the rainy season. By contrast, remarkably high PO43– concentrations (up to 0.8 mg•l–1) were measured during the dry season. Water quality parameters were affected by agricultural activities at all sampled sub-catchments across the catchment, regardless of stream characteristic. Direct NO3– leaching appeared to play a minor role; however, water quality is affected by topsoil fertiliser inputs with impact on small low order streams and larger rivers. Land conversion leaving cropland soils more susceptible to surface erosion by increased overland flow events.
In a third study, the field data were used to parameterise SWAT. The model was tested with different input data and calibrated in SWAT-CUP using the SUFI-2 algorithm. The model was judged reliable to simulate the water balance in the Cerrado. A complete cerrado, pasture and cropland cover was used to analyse the impact of land use on water cycling as well as climate change projections (2039–2058) according to the projections of the RCP 8.5 scenario. The actual evapotranspiration (ET) for the cropland scenario was higher compared to the cerrado cover (+100 mm a–1). Land use change scenarios confirmed that deforestation caused higher annual ET rates explaining partly the trend of decreased streamflow. Taking all climate change scenarios into account, the most likely effect is a prolongation of the dry season (by about one month), with higher peak flows in the rainy season. Consequently, potential threats for crop production with lower soil moisture and increased erosion and sediment transport during the rainy season are likely and should be considered in adaption plans.
From the three studies of the thesis I conclude that land use intensification is likely to seriously limit the Cerrado’s future regarding both agricultural productivity and ecosystem stability. Because only limited data are available for the vast biome, we recommend further field studies to understand the interaction between terrestrial and aquatic systems. This thesis may serve as a valuable database for integrated modelling to investigate the impact of land use and climate change on soil and water resources and to test and develop mitigation measures for the Cerrado in the future.
Nowadays, business processes are increasingly supported by IT services that produce massive amounts of event data during process execution. Aiming at a better process understanding and improvement, this event data can be used to analyze processes using process mining techniques. Process models can be automatically discovered and the execution can be checked for conformance to specified behavior. Moreover, existing process models can be enhanced and annotated with valuable information, for example for performance analysis. While the maturity of process mining algorithms is increasing and more tools are entering the market, process mining projects still face the problem of different levels of abstraction when comparing events with modeled business activities. Mapping the recorded events to activities of a given process model is essential for conformance checking, annotation and understanding of process discovery results. Current approaches try to abstract from events in an automated way that does not capture the required domain knowledge to fit business activities. Such techniques can be a good way to quickly reduce complexity in process discovery. Yet, they fail to enable techniques like conformance checking or model annotation, and potentially create misleading process discovery results by not using the known business terminology.
In this thesis, we develop approaches that abstract an event log to the same level that is needed by the business. Typically, this abstraction level is defined by a given process model. Thus, the goal of this thesis is to match events from an event log to activities in a given process model. To accomplish this goal, behavioral and linguistic aspects of process models and event logs as well as domain knowledge captured in existing process documentation are taken into account to build semiautomatic matching approaches. The approaches establish a pre--processing for every available process mining technique that produces or annotates a process model, thereby reducing the manual effort for process analysts. While each of the presented approaches can be used in isolation, we also introduce a general framework for the integration of different matching approaches.
The approaches have been evaluated in case studies with industry and using a large industry process model collection and simulated event logs. The evaluation demonstrates the effectiveness and efficiency of the approaches and their robustness towards nonconforming execution logs.
Business process management (BPM) is a systematic and structured approach to model, analyze, control, and execute business operations also referred to as business processes that get carried out to achieve business goals. Central to BPM are conceptual models. Most prominently, process models describe which tasks are to be executed by whom utilizing which information to reach a business goal. Process models generally cover the perspectives of control flow, resource, data flow, and information systems.
Execution of business processes leads to the work actually being carried out. Automating them increases the efficiency and is usually supported by process engines. This, though, requires the coverage of control flow, resource assignments, and process data. While the first two perspectives are well supported in current process engines, data handling needs to be implemented and maintained manually. However, model-driven data handling promises to ease implementation, reduces the error-proneness through graphical visualization, and reduces development efforts through code generation.
This thesis addresses the modeling, analysis, and execution of data in business processes and presents a novel approach to execute data-annotated process models entirely model-driven. As a first step and formal grounding for the process execution, a conceptual framework for the integration of processes and data is introduced. This framework is complemented by operational semantics through a Petri net mapping extended with data considerations. Model-driven data execution comprises the handling of complex data dependencies, process data, and data exchange in case of communication between multiple process participants. This thesis introduces concepts from the database domain into BPM to enable the distinction of data operations, to specify relations between data objects of the same as well as of different types, to correlate modeled data nodes as well as received messages to the correct run-time process instances, and to generate messages for inter-process communication. The underlying approach, which is not limited to a particular process description language, has been implemented as proof-of-concept.
Automation of data handling in business processes requires data-annotated and correct process models. Targeting the former, algorithms are introduced to extract information about data nodes, their states, and data dependencies from control information and to annotate the process model accordingly. Usually, not all required information can be extracted from control flow information, since some data manipulations are not specified. This requires further refinement of the process model. Given a set of object life cycles specifying allowed data manipulations, automated refinement of the process model towards containment of all data manipulations is enabled. Process models are an abstraction focusing on specific aspects in detail, e.g., the control flow and the data flow views are often represented through activity-centric and object-centric process models. This thesis introduces algorithms for roundtrip transformations enabling the stakeholder to add information to the process model in the view being most appropriate.
Targeting process model correctness, this thesis introduces the notion of weak conformance that checks for consistency between given object life cycles and the process model such that the process model may only utilize data manipulations specified directly or indirectly in an object life cycle. The notion is computed via soundness checking of a hybrid representation integrating control flow and data flow correctness checking. Making a process model executable, identified violations must be corrected. Therefore, an approach is proposed that identifies for each violation multiple, alternative changes to the process model or the object life cycles.
Utilizing the results of this thesis, business processes can be executed entirely model-driven from the data perspective in addition to the control flow and resource perspectives already supported before. Thereby, the model creation is supported by algorithms partly automating the creation process while model consistency is ensured by data correctness checks.
Redewiedergabeverfahren potenzieren das Moment der sozialen Positionierung in der Interaktion. Charaktere, die zum Beispiel in Erzählungen oder Argumentationen ‚zu Wort kommen‘, werden als Protagonisten und Antagonisten, Täter und Opfer, angeberisch und zurückhaltend konstruiert. Das Bild, das sich Gesprächspartner voneinander machen, wird aber nicht nur durch solche Positionierungen innerhalb der erzählten Welt, sondern auch durch ihre aktuelle Performance als Interaktionsspartner geprägt. All diese Positionierungsaktivitäten stehen in Wechselbeziehung zueinander und können auch aufschlussreiche Spannungsverhältnisse aufweisen.
Ausgehend von einer formalen Beschreibung der verwendeten Mittel zeigt die Analyse narrativ-biographisch geprägter Gespräche unter jungen Erwachsenen, wie in der Interaktion soziale Wirklichkeit ko-konstruiert wird, indem konkret oder stereotyp ‚fremde‘ Kontexte aufgerufen und als Kontrastfolie für die eigene Identitätskonstruktion genutzt werden.
Kaum eine Erfindung veränderte die Kriegführung mehr als das Flugzeug. Vom ersten Motorflug bis zu den ersten Flächenbombardements vergingen nur wenige Jahre. In dieser Zeit richtete sich die englische Luftwaffe konzeptionell anhand ihrer Erfahrungen im Irak aus.
Inwieweit prägten die Erfahrungen während der Aufstandsbekämpfung an der Peripherie des Empire den strategischen Bombenkrieg gegen Deutschland? Es werden die Kampagnen im Irak der 1920er Jahre und der Luftkrieg gegen das »Dritte Reich« betrachtet, die sich in Umfang, Intensität und technischen Rahmenbedingungen zwar erheblich unterschieden. Allerdings bildeten die in beiden Kampagnen eingesetzten Soldaten der RAF das Bindeglied. Mit Hilfe kognitionspsychologischer Methoden und der Analyse von Akteursnetzwerken wird gezeigt, wie die Operationen im Irak die RAF-Offiziere prägten und die Bomberoffensive gegen das Deutsche Reich beeinflussten.
Continental rifts are excellent regions where the interplay between extension, the build-up of topography, erosion and sedimentation can be evaluated in the context of landscape evolution. Rift basins also constitute important archives that potentially record the evolution and migration of species and the change of sedimentary conditions as a result of climatic change. Finally, rifts have increasingly become targets of resource exploration, such as hydrocarbons or geothermal systems. The study of extensional processes and the factors that further modify the mainly climate-driven surface process regime helps to identify changes in past and present tectonic and geomorphic processes that are ultimately recorded in rift landscapes.
The Cenozoic East African Rift System (EARS) is an exemplary continental rift system and ideal natural laboratory to observe such interactions. The eastern and western branches of the EARS constitute first-order tectonic and topographic features in East Africa, which exert a profound influence on the evolution of topography, the distribution and amount of rainfall, and thus the efficiency of surface processes. The Kenya Rift is an integral part of the eastern branch of the EARS and is characterized by high-relief rift escarpments bounded by normal faults, gently tilted rift shoulders, and volcanic centers along the rift axis.
Considering the Cenozoic tectonic processes in the Kenya Rift, the tectonically controlled cooling history of rift shoulders, the subsidence history of rift basins, and the sedimentation along and across the rift, may help to elucidate the morphotectonic evolution of this extensional province. While tectonic forcing of surface processes may play a minor role in the low-strain rift on centennial to millennial timescales, it may be hypothesized that erosion and sedimentation processes impacted by climate shifts associated with pronounced changes in the availability in moisture may have left important imprints in the landscape.
In this thesis I combined thermochronological, geomorphic field observations, and morphometry of digital elevation models to reconstruct exhumation processes and erosion rates, as well as the effects of climate on the erosion processes in different sectors of the rift. I present three sets of results: (1) new thermochronological data from the northern and central parts of the rift to quantitatively constrain the Tertiary exhumation and thermal evolution of the Kenya Rift. (2) 10Be-derived catchment-wide mean denudation rates from the northern, central and southern rift that characterize erosional processes on millennial to present-day timescales; and (3) paleo-denudation rates in the northern rift to constrain climatically controlled shifts in paleoenvironmental conditions during the early Holocene (African Humid Period).
Taken together, my studies show that time-temperature histories derived from apatite fission track (AFT) analysis, zircon (U-Th)/He dating, and thermal modeling bracket the onset of rifting in the Kenya Rift between 65-50 Ma and about 15 Ma to the present. These two episodes are marked by rapid exhumation and, uplift of the rift shoulders. Between 45 and 15 Ma the margins of the rift experienced very slow erosion/exhumation, with the accommodation of sediments in the rift basin.
In addition, I determined that present-day denudation rates in sparsely vegetated parts of the Kenya Rift amount to 0.13 mm/yr, whereas denudation rates in humid and more densely vegetated sectors of the rift flanks reach a maximum of 0.08 mm/yr, despite steeper hillslopes. I inferred that hillslope gradient and vegetation cover control most of the variation in denudation rates across the Kenya Rift today. Importantly, my results support the notion that vegetation cover plays a fundamental role in determining the voracity of erosion of hillslopes through its stabilizing effects on the land surface.
Finally, in a pilot study I highlighted how paleo-denudation rates in climatic threshold areas changed significantly during times of transient hydrologic conditions and involved a sixfold increase in erosion rates during increased humidity. This assessment is based on cosmogenic nuclide (10Be) dating of quartzitic deltaic sands that were deposited in the northern Kenya Rift during a highstand of Lake Suguta, which was associated with the Holocene African Humid Period. Taken together, my new results document the role of climate variability in erosion processes that impact climatic threshold environments, which may provide a template for potential future impacts of climate-driven changes in surface processes in the course of Global Change.
Spots on stellar surfaces are thought to be stellar analogues of sunspots. Thus, starspots are direct manifestations of strong magnetic fields. Their decay rate is directly related to the magnetic diffusivity, which itself is a key quantity for the deduction of an activity cycle length. So far, no single starspot decay has been observed, and thus no stellar activity cycle was inferred from its corresponding turbulent diffusivity.
We investigate the evolution of starspots on the rapidly-rotating K0 giant XX Triangulum. Continuous high-resolution and phase-resolved spectroscopy was obtained with the robotic 1.2-m STELLA telescope on Tenerife over a timespan of six years. With our line-profile inversion code iMap we reconstruct a total of 36 consecutive Doppler maps. To quantify starspot area decay and growth, we match the observed images with simplified spot models based on a Monte-Carlo approach.
It is shown that the surface of XX Tri is covered with large high-latitude and even polar spots and with occasional small equatorial spots. Just over the course of six years, we see a systematically changing spot distribution with various time scales and morphology such as spot fragmentation and spot merging as well as spot decay and formation.
For the first time, a starspot decay rate on another star than the Sun is determined. From our spot-decay analysis we determine an average linear decay rate of D = -0.067±0.006 Gm^2/day. From this decay rate, we infer a turbulent diffusivity of η_τ = (6.3±0.5) x 10^14 cm^2/s and consequently predict an activity cycle of 26±6 years. The obtained cycle length matches very well with photometric observations.
Our time-series of Doppler maps further enables to investigate the differential rotation of XX Tri. We therefore applied a cross-correlation analysis. We detect a weak solar-like differential rotation with a surface shear of α = 0.016±0.003. This value agrees with similar studies of other RS CVn stars.
Furthermore, we found evidence for active longitudes and flip-flops. Whereas the more active longitude is located in phase towards the (unseen) companion star, the weaker active longitude is located at the opposite stellar hemisphere. From their periodic appearance, we infer a flip-flop cycle of ~2 years. Both activity phenomena are common on late-type binary stars.
Last but not least we redetermine several astrophysical properties of XX Tri and its binary system, as large datasets of photometric and spectroscopic observations are available since its last determination in 1999. Additionally, we compare the rotational spot-modulation from photometric and spectroscopic studies.
Die vorliegende Arbeit beschäftigt sich mit der ertrag- und schenkungsteuerlichen Behandlung von Vermögensübertragungen, die disquotal, also nicht dem Beteiligungsverhältnis entsprechend, erfolgen. Bezogen auf das Verhältnis zwischen einer GmbH und ihren Gesellschaftern untersucht die Arbeit die Motive für disquotale Leistungen, die möglichen Vermögensübertragungstatbestände und deren tatsächliche Ausgestaltung. Gewollte disquotale Vermögensübertragungen lassen sich am besten mit verdeckten Gewinnausschüttungen und verdeckten Einlagen erreichen. Die gesellschaftsrechtlichen Beschränkungen spielen hierbei keine große Rolle. Ertragsteuerrechtlich werden die disquotalen Vermögensübertragungen durch die Finanzverwaltung und die Rechtsprechung anerkannt. Schenkungsteuerrechtlich ist die Behandlung dagegen problematisch und teilweise nicht sachdienlich. Im Ergebnis wird ein Lösungsansatz dargeboten, der auch die Besonderheiten im Wirtschaftsleben unter Einschaltung einer GmbH berücksichtigt.
The Barberton Greenstone Belt (BGB) in the northwestern part of South Africa belongs to the few well-preserved remnants of Archean crust. Over the last centuries, the BGB has been intensively studied at surface with detailed mapping of its surfacial geological units and tectonic features. Nevertheless, the deeper structure of the BGB remains poorly understood. Various tectonic evolution models have been developed based on geo-chronological and structural data. These theories are highly controversial and centre on the question whether plate tectonics - as geoscientists understand them today - was already evolving on the Early Earth or whether vertical mass movements driven by the higher temperature of the Earth in Archean times governed continent development.
To get a step closer to answering the questions regarding the internal structure and formation of the BGB, magnetotelluric (MT) field experiments were conducted as part of the German-South African research initiative Inkaba yeAfrica. Five-component MT data (three magnetic and two electric channels) were collected at ~200 sites aligned along six profiles crossing the southern part of the BGB. Tectonic features like (fossil) faults and shear zones are often mineralized and therefore can have high electrical conductivities. Hence, by obtaining an image of the conductivity distribution of the subsurface from MT measurements can provide useful information on tectonic processes.
Unfortunately, the BGB MT data set is heavily affected by man-made electromagnetic noise caused, e.g. by powerlines and electric fences. Aperiodic spikes in the magnetic and corresponding offsets in the electric field components impair the data quality particularly at periods >1 s which are required to image deep electrical structures. Application of common methods for noise reduction like delay filtering and remote reference processing, only worked well for periods <1 s. Within the framework of this thesis two new filtering approaches were developed to handle the severe noise in long period data and obtain reliable processing results. The first algorithm is based on the Wiener filter in combination with a spike detection algorithm. Comparison of data variances of a local site with those of a reference site allows the identification of disturbed time series windows for each recorded channel at the local site. Using the data of the reference site, a Wiener filter algorithm is applied to predict physically meaningful data to replace the disturbed windows. While spikes in the magnetic channels are easily recognized and replaced, steps in the electric channels are more difficult to detect depending on their offset. Therefore, I have implemented a novel approach based on time series differentiation, noise removal and subsequent integration to overcome this obstacle. A second filtering approach where spikes and steps in the time series are identified using a comparison of the short and long time average of the data was also implemented as part of my thesis. For this filtering approach the noise in the form of spikes and offsets in the data is treated by an interpolation of the affected data samples. The new developments resulted in a substantial data improvement and allowed to gain one to two decades of data (up to 10 or 100 s).
The re-processed MT data were used to image the electrical conductivity distribution of the BGB by 2D and 3D inversion. Inversion models are in good agreement with the surface geology delineating the highly resistive rocks of the BGB from surrounding more conductive geological units. Fault zones appear as conductive structures and can be traced to depths of 5 to 10 km. 2D models suggest a continuation of the faults further south across the boundary of the BGB. Based on the shallow tectonic structures (fault system) within the BGB compared to deeply rooted resistive batholiths in the area, tectonic models including both vertical mass transport and in parts present-day style plate tectonics seem to be most likely for the evolution of the BGB.
Der Franchisevertrag
(2015)
Spectral fingerprinting
(2015)
Current research on runoff and erosion processes, as well as an increasing demand for sustainable watershed management emphasize the need for an improved understanding of sediment dynamics. This involves the accurate assessment of erosion rates and sediment transfer, yield and origin. A variety of methods exist to capture these processes at the catchment scale. Among these, sediment fingerprinting, a technique to trace back the origin of sediment, has attracted increasing attention by the scientific community in recent years. It is a two-step procedure, based on the fundamental assumptions that potential sources of sediment can be reliably discriminated based on a set of characteristic ‘fingerprint’ properties, and that a comparison of source and sediment fingerprints allows to quantify the relative contribution of each source.
This thesis aims at further assessing the potential of spectroscopy to assist and improve the sediment fingerprinting technique. Specifically, this work focuses on (1) whether potential sediment sources can be reliably identified based on spectral features (‘fingerprints’), whether (2) these spectral fingerprints permit the quantification of relative source contribution, and whether (3) in situ derived source information is sufficient for this purpose. Furthermore, sediment fingerprinting using spectral information is applied in a study catchment to (4) identify major sources and observe how relative source contributions change between and within individual flood events. And finally, (5) spectral fingerprinting results are compared and combined with simultaneous sediment flux measurements to study sediment origin, transport and storage behaviour.
For the sediment fingerprinting approach, soil samples were collected from potential sediment sources within the Isábena catchment, a meso-scale basin in the central Spanish Pyrenees. Undisturbed samples of the upper soil layer were measured in situ using an ASD spectroradiometer and subsequently sampled for measurements in the laboratory. Suspended sediment was sampled automatically by means of ISCO samplers at the catchment as well as at the five major subcatchment outlets during flood events, and stored fine sediment from the channel bed was collected from 14 cross-sections along the main river. Artificial mixtures of known contributions were produced from source soil samples. Then, all source, sediment and mixture samples were dried and spectrally measured in the laboratory. Subsequently, colour coefficients and physically based features with relation to organic carbon, iron oxide, clay content and carbonate, were calculated from all in situ and laboratory spectra. Spectral parameters passing a number of prerequisite tests were submitted to principal component analyses to study natural clustering of samples, discriminant function analyses to observe source differentiation accuracy, and a mixing model for source contribution assessment. In addition, annual as well as flood event based suspended sediment fluxes from the catchment and its subcatchments were calculated from rainfall, water discharge and suspended sediment concentration measurements using rating curves and Quantile Regression Forests. Results of sediment flux monitoring were interpreted individually with respect to storage behaviour, compared to fingerprinting source ascriptions and combined with fingerprinting to assess their joint explanatory potential.
In response to the key questions of this work, (1) three source types (land use) and five spatial sources (subcatchments) could be reliably discriminated based on spectral fingerprints. The artificial mixture experiment revealed that while (2) laboratory parameters permitted source contribution assessment, (3) the use of in situ derived information was insufficient. Apparently, high discrimination accuracy does not necessarily imply good quantification results. When applied to suspended sediment samples of the catchment outlet, the spectral fingerprinting approach was able to (4) quantify the major sediment sources: badlands and the Villacarli subcatchment, respectively, were identified as main contributors, which is consistent with field observations and previous studies. Thereby, source contribution was found to vary both, within and between individual flood events. Also sediment flux was found to vary considerably, annually as well as seasonally and on flood event base. Storage was confirmed to play an important role in the sediment dynamics of the studied catchment, whereas floods with lower total sediment yield tend to deposit and floods with higher yield rather remove material from the channel bed. Finally, a comparison of flux measurements with fingerprinting results highlighted the fact that (5) immediate transport from sources to the catchment outlet cannot be assumed. A combination of the two methods revealed different aspects of sediment dynamics that none of the techniques could have uncovered individually.
In summary, spectral properties provide a fast, non-destructive, and cost-efficient means to discriminate and quantify sediment sources, whereas, unfortunately, straight-forward in situ collected source information is insufficient for the approach. Mixture modelling using artificial mixtures permits valuable insights into the capabilities and limitations of the method and similar experiments are strongly recommended to be performed in the future. Furthermore, a combination of techniques such as e.g. (spectral) sediment fingerprinting and sediment flux monitoring can provide comprehensive understanding of sediment dynamics.
Microsaccades
(2015)
The first thing we do upon waking is open our eyes. Rotating them in our eye sockets, we scan our surroundings and collect the information into a picture in our head. Eye movements can be split into saccades and fixational eye movements, which occur when we attempt to fixate our gaze. The latter consists of microsaccades, drift and tremor. Before we even lift our eye lids, eye movements – such as saccades and microsaccades that let the eyes jump from one to another position – have partially been prepared in the brain stem. Saccades and microsaccades are often assumed to be generated by the same mechanisms. But how saccades and microsaccades can be classified according to shape has not yet been reported in a statistical manner. Research has put more effort into the investigations of microsaccades’ properties and generation only since the last decade. Consequently, we are only beginning to understand the dynamic processes governing microsaccadic eye movements. Within this thesis, the dynamics governing the generation of microsaccades is assessed and the development of a model for the underlying processes. Eye movement trajectories from different experiments are used, recorded with a video-based eye tracking technique, and a novel method is proposed for the scale-invariant detection of saccades (events of large amplitude) and microsaccades (events of small amplitude). Using a time-frequency approach, the method is examined with different experiments and validated against simulated data. A shape model is suggested that allows for a simple estimation of saccade- and microsaccade related properties. For sequences of microsaccades, in this thesis a time-dynamic Markov model is proposed, with a memory horizon that changes over time and which can best describe sequences of microsaccades.
Intuitively, it is clear that neural processes and eye movements in reading are closely connected, but only few studies have investigated both signals simultaneously. Instead, the usual approach is to record them in separate experiments and to subsequently consolidate the results. However, studies using this approach have shown that it is feasible to coregister eye movements and EEG in natural reading and contributed greatly to the understanding of oculomotor processes in reading. The present thesis builds upon that work, assessing to what extent coregistration can be helpful for sentence processing research.
In the first study, we explore how well coregistration is suited to study subtle effects common to psycholinguistic experiments by investigating the effect of distance on dependency resolution. The results demonstrate that researchers must improve the signal-to-noise ratio to uncover more subdued effects in coregistration. In the second study, we compare oscillatory responses in different presentation modes. Using robust effects from world knowledge violations, we show that the generation and retrieval of memory traces may differ between natural reading and word-by-word presentation. In the third study, we bridge the gap between our knowledge of behavioral and neural responses to integration difficulties in reading by analyzing the EEG in the context of regressive saccades. We find the P600, a neural indicator of recovery processes, when readers make a regressive saccade in response to integration difficulties.
The results in the present thesis demonstrate that coregistration can be a useful tool for the study of sentence processing. However, they also show that it may not be suitable for some questions, especially if they involve subtle effects.
Im Rahmen der EU-weiten REACH-Verordnung haben Alternativmethoden zum Tierversuch in der Toxikologie an Bedeutung gewonnen. Die Alternativmethoden gliedern sich auf in In-vitro- und In-silico-Methoden. In dieser Dissertation wurden verschiedene Konzepte der In-silico-Toxikologie behandelt.
Die bearbeiteten Themen reichen von quantitativen Strukturaktivitätsbeziehungen (QSAR) über eine neue Herangehensweise an das gängige Konzept zur Festlegung von Grenzwerten bis hin zu computerbasierten Modellierungen zum Alkohol- und Bisphenol-A-Stoffwechsel.
Das Kapitel über QSAR befasst sich im Wesentlichen mit der Erstellung und Analyse einer Datenbank mit 878 Substanzen, die sich aus Tierversuchsstudien aus dem Archiv des Bundesinstituts für Risikobewertung zusammensetzt. Das Design wurde dabei an eine bereits bestehende Datenbank angepasst, um so einen möglichst großen Datenpool zu generieren. In der Analyse konnte u.a. gezeigt werden, dass Stoffe mit niedrigerem Molekulargewicht ein erhöhtes Potential für toxikologische Schäden aufwiesen als größere Moleküle.
Mit Hilfe des sogenannten TTC-Konzepts können Grenzwerte für Stoffe geringer Exposition festgelegt werden, zu denen keine toxikologischen Daten zur Verfügung stehen. In dieser Arbeit wurden für die Stoffe dreier Datenbanken entsprechende Grenzwerte festgelegt. Es erfolgte zunächst eine gängige strukturbasierte Aufteilung der Substanzen in die Kategorien "nicht toxisch", "möglicherweise toxisch" und "eindeutig toxisch". Substanzen, die aufgrund ihrer Struktur in eine der drei Klassen eingeordnet werden, erhalten den entsprechenden Grenzwert. Da in die dritte Klasse auch Stoffe eingeordnet werden, deren Toxizität nicht bestimmbar ist, ist sie sehr groß. Daher wurden in dieser Arbeit die ersten beiden Klassen zusammengelgt, um einen größeren Datenpool zu ermöglichen. Eine weitere Neuerung umfasst die Erstellung eines internen Grenzwerts. Diese Vorgehensweise hat den Vorteil, dass der Expositionsweg herausgerechnet wird und somit beispielsweise Studien mit oraler Verabreichung mit Studien dermaler Verabreichung verglichen werden können.
Mittels physiologisch basiertem kinetischem Modelling ist es möglich, Vorgänge im menschlichen Körper mit Hilfe spezieller Software nachzuvollziehen. Durch diese Vorgehensweise können Expositionen von Chemikalien simuliert werden. In einem Teil der Arbeit wurden Alkoholexpositionen von gestillten Neugeborenen simuliert, deren Mütter unmittelbar zuvor alkoholische Getränke konsumiert hatten. Mit dem Modell konnte gezeigt werden, dass die Expositionen des Kindes durchweg gering waren. Nach einem Glas Wein wurden Spitzenkonzentrationen im Blut von Neugeborenen von 0,0034 Promille ermittelt. Zum Vergleich wurde die Exposition durch ein für Säuglinge zugelassenes alkoholhaltiges pflanzliches Arzneimittel simuliert. Hier wurden Spitzenkonzentrationen von 0,0141 Promille erreicht. Daher scheinen Empfehlungen wie gelegentlicher Konsum ohne schädigende Wirkung auf das Kind wissenschaftlich fundiert zu sein.
Ein weiteres Kinetik-Modell befasste sich mit dem Stoffwechsel von Bisphenol A. Teils widersprüchliche Daten zur Belastung mit BPA in der wissenschaftlichen Literatur führen wiederholt zu Anregungen, den Grenzwert der Chemikalie anzupassen. Die Funktionalität der am Metabolismus beteiligten Enzyme kann je nach Individuum unterschiedlich ausgeprägt sein. Mittels Modellings konnte hier gezeigt werden, dass dies maßgeblich dazu führt, dass sich berechnete Plasmaspiegel von Individuen bis zu 4,7-fach unterscheiden.
Die Arbeit konnte somit einen Beitrag zur Nutzung und Weiterentwicklung von In-silico-Modellen für diverse toxikologische Fragestellungen leisten.
Stream water and groundwater are important fresh water resources but their water quality is deteriorated by harmful solutes introduced by human activities. The interface between stream water and the subsurface water is an important zone for retention, transformation and attenuation of these solutes. Streambed structures enhance these processes by increased water and solute exchange across this interface, denoted as hyporheic exchange.
This thesis investigates the influence of hydrological and morphological factors on hyporheic water and solute exchange as well as redox-reactions in fluvial streambed structures on the intermediate scale (10–30m). For this purpose, a three-dimensional numerical modeling approach for coupling stream water flow with porous media flow is used. Multiple steady state stream water flow scenarios over different generic pool-riffle morphologies and a natural in-stream gravel bar are simulated by a computational fluid dynamics code that provides the hydraulic head distribution at the streambed. These heads are subsequently used as the top boundary condition of a reactive transport groundwater model of the subsurface beneath the streambed. Ambient groundwater that naturally interacts with the stream water is considered in scenarios of different magnitudes of downwelling stream water (losing case) and upwelling groundwater (gaining case). Also, the neutral case, where stream stage and groundwater levels are balanced is considered. Transport of oxygen, nitrate and dissolved organic carbon and their reaction by aerobic respiration and denitrification are modeled.
The results show that stream stage and discharge primarily induce hyporheic exchange flux and solute transport with implications for specific residence times and reactions at both the fully and partially submerged structures. Gaining and losing conditions significantly diminish the extent of the hyporheic zone, the water exchange flux, and shorten residence times for both the fully and partially submerged structures. With increasing magnitude of gaining or losing conditions, these metrics exponentially decrease.
Stream water solutes are transported mainly advectively into the hyporheic zone and hence their influx corresponds directly to the infiltrating water flux. Aerobic respiration takes place in the shallow streambed sediments, coinciding to large parts with the extent of the hyporheic exchange flow. Denitrification occurs mainly as a “reactive fringe” surrounding the aerobic zone, where oxygen concentration is low and still a sufficient amount of stream water carbon source is available. The solute consumption rates and the efficiency of the aerobic and anaerobic reactions depend primarily on the available reactive areas and the residence times, which are both controlled by the interplay between hydraulic head distribution at the streambed and the gradients between stream stage and ambient groundwater. Highest solute consumption rates can be expected under neutral conditions, where highest solute flux, longest residence times and largest extent of the hyporheic exchange occur. The results of this thesis show that streambed structures on the intermediate scale have a significant potential to contribute to a net solute turnover that can support a healthy status of the aquatic ecosystem.
We study segregation of the subducted oceanic crust (OC) at the core mantle boundary and its ability to accumulate and form large thermochemical piles (such as the seismically observed Large Low Shear Velocity Provinces - LLSVPs). Our high-resolution numerical simulations suggest that the longevity of LLSVPs for up to three billion years, and possibly longer, can be ensured by a balance in the rate of segregation of high-density OC-material to the CMB, and the rate of its entrainment away from the CMB by mantle upwellings.
For a range of parameters tested in this study, a large-scale compositional anomaly forms at the CMB, similar in shape and size to the LLSVPs. Neutrally buoyant thermochemical piles formed by mechanical stirring - where thermally induced negative density anomaly is balanced by the presence of a fraction of dense anomalous material - best resemble the geometry of LLSVPs. Such neutrally buoyant piles tend to emerge and survive for at least 3Gyr in simulations with quite different parameters. We conclude that for a plausible range of values of density anomaly of OC material in the lower mantle - it is likely that it segregates to the CMB, gets mechanically mixed with the ambient material, and forms neutrally buoyant large scale compositional anomalies similar in shape to the LLSVPs.
We have developed an efficient FEM code with dynamically adaptive time and space resolution, and marker-in-cell methodology. This enabled us to model thermochemical mantle convection at realistically high convective vigor, strong thermally induced viscosity variations, and long term evolution of compositional fields.
In this thesis we study reciprocal classes of Markov chains. Given a continuous time Markov chain on a countable state space, acting as reference dynamics, the associated reciprocal class is the set of all probability measures on path space that can be written as a mixture of its bridges. These processes possess a conditional independence property that generalizes the Markov property, and evolved from an idea of Schrödinger, who wanted to obtain a probabilistic interpretation of quantum mechanics.
Associated to a reciprocal class is a set of reciprocal characteristics, which are space-time functions that determine the reciprocal class. We compute explicitly these characteristics, and divide them into two main families: arc characteristics and cycle characteristics. As a byproduct, we obtain an explicit criterion to check when two different Markov chains share their bridges.
Starting from the characteristics we offer two different descriptions of the reciprocal class, including its non-Markov probabilities.
The first one is based on a pathwise approach and the second one on short time asymptotic. With the first approach one produces a family of functional equations whose only solutions are precisely the elements of the reciprocal class. These equations are integration by parts on path space associated with derivative operators which perturb the paths by mean of the addition of random loops. Several geometrical tools are employed to construct such formulas. The problem of obtaining sharp characterizations is also considered, showing some interesting connections with discrete geometry. Examples of such formulas are given in the framework of counting processes and random walks on Abelian groups, where the set of loops has a group structure.
In addition to this global description, we propose a second approach by looking at the short time behavior of a reciprocal process. In the same way as the Markov property and short time expansions of transition probabilities characterize Markov chains, we show that a reciprocal class is characterized by imposing the reciprocal property and two families of short time expansions for the bridges. Such local approach is suitable to study reciprocal processes on general countable graphs. As application of our characterization, we considered several interesting graphs, such as lattices, planar
graphs, the complete graph, and the hypercube.
Finally, we obtain some first results about concentration of measure implied by lower bounds on the reciprocal characteristics.
The relationship between nutrition and the development of chronic diseases including metabolic syndrome, diabetes mellitus, cancer and cardiovascular disease has been well studied. On the other hand, changes in the GH-IGF-1 axis in association with nutrition-related diseases have been reported. The interplay between GH, total IGF-1 and different inhibitory and stimulatory kinds of IGF-1 binding proteins (IGFBPs) results in IGF-1 bioactivity, the ability of IGF-1 to induce phosphorylation of its receptor and consequently its signaling. Moreover, IGF-1 bioactivity is sufficient to reflect any change in the GH-IGF-1 system. Accumulating evidence suggests that both of high protein diet, characterized by increased glucagon secretion, and insulin-induced hypoglycemia increase mortality rate and the mechanisms are unclear. However both of glucagon and insulin-induced hypoglycemia are potent stimuli of GH secretion. The aim of the current study was to identify the impact of glucagon and insulin-induced hypoglycemia on IGF-1 bioactivity as possible mechanisms. In a double-blind placebo-controlled study, glucagon was intramuscularly administrated in 13 type 1 diabetic patients (6 males /7 females; [BMI]: 24.8 ± 0.95 kg/m2), 11 obese subjects (OP; 5/ 6; 34.4 ± 1.7 kg/m2), and 13 healthy lean participants (LP; 6/ 7; 21.7 ± 0.6 kg/m2), whereas 12 obese subjects (OP; 6/ 6; 34.4 ± 1.7 kg/m2), and 13 healthy lean participants (LP; 6/ 7; 21.7 ± 0.6 kg/m2) performed insulin tolerance test in another double-blind placebo-controlled study and changes in GH, total IGF-1, IGF binding proteins (IGFBPs) and IGF-1 bioactivity, measured by the cell-based KIRA method, were investigated. In addition, the interaction between the metabolic hormones (glucagon and insulin) and the GH-IGF-1 system on the transcriptional level was studied using mouse primary hepatocytes. In this thesis, glucagon decreased IGF-1 bioactivity in humans independently of endogenous insulin levels, most likely through modulation of IGFBP-1 and-2 levels. The glucagon-induced reduction in IGF-1 bioactivity may represent a novel mechanism underlying the impact of glucagon on GH secretion and may explain the negative effect of high protein diet related to increased cardiovascular risk and mortality rate. In addition, insulin-induced hypoglycemia was correlated with a decrease in IGF-1 bioactivity through up-regulation of IGFBP-2. These results may refer to a possible and poorly explored mechanism explaining the strong association between hypoglycemia and increased cardiovascular mortality among diabetic patients.
This dissertation investigates the working memory mechanism subserving human sentence processing and its relative contribution to processing difficulty as compared to syntactic prediction. Within the last decades, evidence for a content-addressable memory system underlying human cognition in general has accumulated (e.g., Anderson et al., 2004). In sentence processing research, it has been proposed that this general content-addressable architecture is also used for language processing (e.g., McElree, 2000).
Although there is a growing body of evidence from various kinds of linguistic dependencies that is consistent with a general content-addressable memory subserving sentence processing (e.g., McElree et al., 2003; VanDyke2006), the case of reflexive-antecedent dependencies has challenged this view. It has been proposed that in the processing of reflexive-antecedent dependencies, a syntactic-structure based memory access is used rather than cue-based retrieval within a content-addressable framework (e.g., Sturt, 2003).
Two eye-tracking experiments on Chinese reflexives were designed to tease apart accounts assuming a syntactic-structure based memory access mechanism from cue-based retrieval (implemented in ACT-R as proposed by Lewis and Vasishth (2005).
In both experiments, interference effects were observed from noun phrases which syntactically do not qualify as the reflexive's antecedent but match the animacy requirement the reflexive imposes on its antecedent. These results are interpreted as evidence against a purely syntactic-structure based memory access. However, the exact pattern of effects observed in the data is only partially compatible with the Lewis and Vasishth cue-based parsing model.
Therefore, an extension of the Lewis and Vasishth model is proposed. Two principles are added to the original model, namely 'cue confusion' and 'distractor prominence'.
Although interference effects are generally interpreted in favor of a content-addressable memory architecture, an alternative explanation for interference effects in reflexive processing has been proposed which, crucially, might reconcile interference effects with a structure-based account.
It has been argued that interference effects do not necessarily reflect cue-based retrieval interference in a content-addressable memory but might equally well be accounted for by interference effects which have already occurred at the moment of encoding the antecedent in memory (Dillon, 2011).
Three experiments (eye-tracking and self-paced reading) on German reflexives and Swedish possessives were designed to tease apart cue-based retrieval interference from encoding interference. The results of all three experiments suggest that there is no evidence that encoding interference affects the retrieval of a reflexive's antecedent.
Taken together, these findings suggest that the processing of reflexives can be explained with the same cue-based retrieval mechanism that has been invoked to explain syntactic dependency resolution in a range of other structures. This supports the view that the language processing system is located within a general cognitive architecture, with a general-purpose content-addressable working memory system operating on linguistic expressions.
Finally, two experiments (self-paced reading and eye-tracking) using Chinese relative clauses were conducted to determine the relative contribution to sentence processing difficulty of working-memory processes as compared to syntactic prediction during incremental parsing.
Chinese has the cross-linguistically rare property of being a language with subject-verb-object word order and pre-nominal relative clauses. This property leads to opposing predictions of expectation-based
accounts and memory-based accounts with respect to the relative processing difficulty of subject vs. object relatives.
Previous studies showed contradictory results, which has been attributed to different kinds local ambiguities confounding the materials (Lin and Bever, 2011). The two experiments presented are the first to compare Chinese relatives clauses in syntactically unambiguous contexts.
The results of both experiments were consistent with the predictions of the expectation-based account of sentence processing but not with the memory-based account. From these findings, I conclude that any theory of human sentence processing needs to take into account the power of predictive processes unfolding in the human mind.
How does perceptual experience make us knowledgeable? This book argues that the answer lies in the nature of perceptual experience: this experience involves conceptual capacities and is a relation between perceiver and world. The author develops her position via a critical examination of conceptualist and relationist theories of perception. A discussion of recent work in vision science rounds up this contribution to the philosophy of perception.
Learners' Little Helper
(2015)
Effects of a novel non-steroidal mineralocorticoid receptor antagonist on cardiac hypertrophy
(2015)
Ziel dieser Arbeit war die Synthese und Charakterisierung von neuartigen fluoreszierenden Copolymeren zur Analytdetektion in wässrigen Systemen. Das Detektionssystem sollte ein einfaches Schalten der Fluoreszenz bei Analytbindung „Aus“ bzw. Verdrängung „An“ ermöglichen. Dafür wurde die Synthese eines funktionalisierten Monomers so geplant, dass sich Fluorophor und Analyt innerhalb derselben Monomereinheit in direkter Nachbarschaft zueinander befinden. So sollten bei Erkennung des Analyten durch eine mit einem Fluoreszenzlöscher funktionalisierte Erkennungsstruktur Fluorophor und Löscher in einen vorgegebenen Abstand zueinander gezwungen und die Fluoreszenz des Fluorophors effizient gelöscht werden. Bei anschließender Verdrängung der Erkennungseinheit durch einen stärker bindenden Analyten sollte die Fluoreszenz wieder „angeschaltet“ werden. Eine weitere Zielstellung für das Detektionssystem war eine hohe Löslichkeit und Fluoreszenzintensität in Wasser. Da die Anwendung solcher Sensoren besonders in der Medizin und Biologie, z.B. für Schnellerkennungstest von Pathogenen, von Interesse ist, ist die Kompatibilität mit wässrigen Medien essentiell. Die funktionalisierten Monomere wurden frei radikalisch mit N Vinyl-pyrrolidon bzw. N Vinyl¬caprolactam zu wasserlöslichen, fluoreszierenden Copolymeren umgesetzt. In den N-Vinyl¬pyrrolidon-Polymeren (PNVP) wurde RhodaminB, in den thermoresponsiven N Vinyl¬caprolactam-Polymeren (PNVCL) ein Naphthalsäureimid als Fluorophor verwendet. Während Rhodamine eine hohe Fluoreszenzintensität, gute Quantenausbeuten und hohen Extinktionskoeffizienten in Wasser zeigen, sind Naphthalsäure¬imide umgebungssensitive Chromophore, die bei Änderung ihrer Lösungsmittelumgebung, wie z.B. beim Kollaps eines thermoresponsiven Polymers in Wasser, ihre Fluoreszenzintensität und Quantenausbeute drastisch ändern können. Der Vorteil der hier verwendeten Strategie der Monomersynthese liegt darin, dass bei jeder spezifischen Analytdetektion durch eine Erkennungseinheit die Fluoreszenz effizient gelöscht bzw. bei Verdrängung durch einen stärker bindenden Analyten wieder „angeschaltet“ wird. Dieses Prinzip wird bereits vielfach in der Biologie in sogenannten „Molecular Beacons“ ausgenutzt, wobei ein Fluorophor und ein Löscher durch spezifische DNA Basenpaarung in einen vorgegebenen Abstand zueinander gezwungen werden und so ein „Schalten“ der Fluoreszenz ermöglichen. Aufgrund der vorgegebenen Struktur der DNA Basensequenzen ist es jedoch nicht direkt auf andere Erkennungsreaktionen übertragbar. Daher wurde ein Modellsystem entwickelt, welches die Möglichkeit bietet Analyt, Erkennungseinheit und Signalgeber variabel, je nach Anforderungen des Systems, auszutauschen. So soll es möglich sein, den Sensor a priori für jede Erkennungs¬reaktion zu verwenden. Als Modell Bindungs¬paare wurden ß Cyclodextrin/Adamantan und Con¬cana¬valinA/Mannose ausgewählt. Adamantan bzw. Mannose wurde als Analyt zusammen mit dem Fluorophor in das Polymer eingebunden. ß Cyclo¬dextrin (ß CD) bzw. ConcanavalinA (ConA) wurde als Erkennungsstruktur an einem Fluoreszenzlöscher immobilisiert. Polymer-basierte Fluoreszenzsensoren sind in der Fachliteratur gut dokumentiert. In der Regel sind Signalgeber und Analyt jedoch statistisch im Polymer verteilt, da sie sich entweder in unterschiedlichen Monomereinheiten befinden oder die Funktionalisierung durch eine polymeranaloge Umsetzung erfolgt. Der gewählte Ansatz Fluorophor und Analyt innerhalb derselben Monomereinheit einzubinden, soll bei jeder Erkennungsreaktion des Analyten zu einer Änderung der Signalintensität des Fluorophors führen. Eine hohe Signalintensität bei Analytdetektion ist wünschenswert, insbesondere für Erkennungsreaktionen, die mit möglichst geringem apparativem Aufwand, am besten mit dem bloßen Auge zu verfolgen sein sollen. Des Weiteren ist es möglich den Fluorophorgehalt im Polymer genau einzustellen und so Selbstlöschung zu vermeiden. Die synthetisierten Polymere haben einen Fluorophorgehalt von 0,01 mol% bis 0,5 mol%. Für die RhodaminB haltigen Polymere zeigte sich, dass ein Fluorophorgehalt unterhalb 0,1 mol% im Polymer die höchsten Ausbeuten, Molmassen und Quantenausbeuten liefert. Für die Naphthalsäureimid haltigen Polymere hingegen wurden auch für einen Fluorophorgehalt von bis zu 1 mol% hohe Ausbeuten und Molmassen erreicht. Die Naphthalsäureimid haltigen Polymere haben jedoch in wässriger Lösungsmittelumgebung nur geringe Quantenausbeuten. Als Fluoreszenzlöscher wurden Goldnanopartikel synthetisiert, die mit den entsprechenden Erkennungsstrukturen (ß-CD oder ConA) für den verwendeten Analyten funktionalisiert wurden. Goldnanopartikel als Löscher bieten den Vorteil, dass ihre Dispergierbarkeit in einem Lösemittel durch Funktionalisierung ihrer Hülle gezielt gesteuert werden kann. Durch die hohe Affinität von Goldnanopartikeln zu Thiolen und Aminen konnten sie mit Hilfe einfacher Syntheseschritte mit Thio ß CD Derivaten bzw. ConA funktionalisiert werden. In der hier vorgelegten Arbeit sollte ein Modellsystem für einen solches fluoreszenz-basiertes Detektionssystem in Wasser entwickelt werden. Nachfolgend werden die zu erfüllenden strukturellen Voraussetzungen für die Synthese eines solchen Sensors nochmals zusammengefasst:
1. Verwendung eines Fluorophors, der eine hohe Signalintensität zeigt.
2. Analyt bzw. Erkennungseinheit soll sich im Abstand von wenigen Nanometern zum Signalgeber befinden, um bei jeder Detektionsreaktion die Signalintensität des Signalgebers beeinflussen zu können.
3. Die Detektionseinheit benötigt eine funktionelle Gruppe zur Immobilisierung. Immobilisierung kann z.B. durch Einbindung in ein Polymer erfolgen.
4. Der Fluorophor soll bei Änderung seiner lokalen Umgebung, durch Binden eines Löschers oder Änderung seiner Lösemittelumgebung seine Fluoreszenzeigenschaften drastisch ändern.
5. Die Reaktion sollte schnell und mit möglichst geringem apparativem Aufwand, am besten mit bloßem Auge zu verfolgen sein.
Für das ß-CD/Adamantan Modellsystem wurde ein Fluoreszenz Aus/An Sensor entwickelt, der bei Binden ß CD funktionalisierter Goldnanopartikel an das polymergebundene Adamantan die Fluoreszenz des RhodaminB Fluorophors effizient löscht und bei Verdrängung der Goldnanopartikel wieder zurück gewinnt. Dies konnte auch mit bloßem Auge verfolgt werden.
Für die Naphthalsäureimid Monomere, die mit NVCL copolymerisiert wurden, wurde abhängig von der lokalen Umgebung des Fluorophors eine unterschiedliche Verstärkung der Fluoreszenzintensität bei Überschreiten des Trübungspunktes des Polymers gefunden. Dabei zeigte sich, dass die Einführung eines Abstandshalters zwischen Polymerrückgrat und Fluorophor zu einer großen Fluoreszenz¬verstärkung führt, während sich ohne Abstandshalter die Fluoreszenzintensität bei Über¬schreiten des Trübungspunktes kaum ändert.
Two of the most controversial issues concerning the late Cenozoic evolution of the Andean orogen are the timing of uplift of the intraorogenic Puna plateau and its eastern border, the Eastern Cordillera, and ensuing changes in climatic and surface-process conditions in the intermontane basins of the NW-Argentine Andes. The Eastern Cordillera separates the internally drained, arid Puna from semi-arid intermontane basins and the humid sectors of the Andean broken foreland and the Subandean fold-and-thrust belt to the east. With elevations between 4,000 and 6,000 m the eastern flanks of the Andes form an efficient orographic barrier with westward-increasing elevation and asymmetric rainfall distribution and amount with respect to easterly moisture-bearing winds. This is mirrored by pronounced gradients in the efficiency of surface processes that erode and re-distribute sediment from the uplifting ranges. Although the overall pattern of deformation and uplift in this sector of the southern central Andes shows an eastward migration of deformation, a well-developed deformation front does not exist and uplift and associated erosion and sedimentary processes are highly disparate in space and time. In addition, periodic deformation within intermontane basins, and continued diachronous foreland uplifts associated with the reactivation of inherited basement structures furthermore make a rigorous assessment of the spatiotemporal uplift patterns difficult.
This thesis focuses on the tectonic evolution of the Eastern Cordillera of NW Argentina, the depositional history of its intermontane sedimentary basins, and the regional topographic evolution of the eastern flank of the Puna Plateau. The intermontane basins of the Eastern Cordillera and the adjacent morphotectonic provinces of the Sierras Pampeanas and the Santa Bárbara System are akin to reverse fault bounded, filled, and partly coalesced sedimentary basins of the Puna Plateau. In contrast to the Puna basins, however, which still form intact morphologic entities, repeated deformation, erosion, and re-filling have impacted the basins in the Eastern Cordillera. This has resulted in a rich stratigraphy of repeated basin fills, but many of these basins have retained vestiges of their early depositional history that may reach back in time when these areas were still part of a contiguous and undeformed foreland basin. Fortunately, these strata also contain abundant volcanic ashes that are not only important horizons to decipher tectono-sedimentary events through U-Pb geochronology and geochemical correlation, but they also represent terrestrial recorders of the hydrogen-isotope composition of ancient meteoric waters that can be compared to the isotopic composition of modern meteoric water. The ash horizons are thus unique recorders of past environmental conditions and lend themselves to tracking the development of rainfall barriers and tectonically forced climate and environmental change through time.
U-Pb zircon geochronology and paleocurrent reconstructions of conglomerate sequences in the Humahuaca Basin of the Eastern Cordillera at 23.5° S suggest that the basin was an integral part of a largely unrestricted depositional system until 4.2 Ma, which subsequently became progressively decoupled from the foreland by range uplifts to the east that forced easterly moisture-bearing winds to precipitate in increasingly eastward locations. Multiple cycles of severed hydrological conditions and drainage re-capture are identified together with these processes that were associated with basin filling and sediment evacuation, respectively. Moreover, systematic relationships among faults, regional unconformities and deformed landforms reveal a general pattern of intra-basin deformation that appears to be linked with basin-internal deformation during or subsequent to episodes of large-scale sediment removal. Some of these observations are supported by variations in the hydrogen stable isotope composition of volcanic glass from the Neogene to Quaternary sedimentary record, which can be related to spatiotemporal changes in topography and associated orographic effects. δDg values in the basin strata reveal two main trends associated with surface uplift in the catchment area between 6.0 and 3.5 Ma and the onset of semiarid conditions in the basin following the attainment of threshold elevations for effective orographic barriers to the east after 3.5 Ma. The disruption of sediment supply from western sources after 4.2 Ma and subsequent hinterland aridification, moreover, emphasize the possibility that these processes were related to lateral orogenic growth of the adjacent Puna Plateau. As a result of the hinterland aridification the regions in the orogen interior have been characterized by an inefficient fluvial system, which in turn has helped maintaining internal drainage conditions, sediment storage, and relief reduction within high-elevation basins.
The diachronous nature of basin formation and impacts on the fluvial system in the adjacent broken foreland is underscored by the results of detailed sediment provenance and paleocurrent analyses, as well as U-Pb zircon geochronology in the Lerma and Metán basins at ca. 25° S. This is particularly demonstrated by the isolated uplift of the Metán range at ~10 Ma, which is more than 50 km away from the presently active orogenic front along the eastern Puna margin and the Eastern Cordillera to the west. At about 5 Ma, Puna-sourced sediments disappear from the foreland record, documenting further range uplifts in the Eastern Cordillera and hydrological isolation of the neighboring Angastaco Basin from the foreland. Finally, during the late Pliocene and Quaternary, deformation has been accommodated across the entire foreland and is still active. To elucidate the interactions between tectonically controlled changes in elevation and their impact on atmospheric circulation processes in this region, this thesis provides additional, temporally well-constrained hydrogen stable isotope results of volcanic glass samples from the broken foreland, including the Angastaco Basin, and other intermontane basins farther south. The results suggest similar elevations of intermontane basins and the foreland sectors prior to ca. 7 Ma. In case of the Angastaco Basin the region was affected by km-scale surface uplift of the basin. A comparison with coeval isotope data collected from sedimentary sequences in the Puna plateau explains rapid shifts in the intermontane δDg record and supports the notion of recurring phases of enhanced deep convection during the Pliocene, and thus climatic conditions during the middle to late Pliocene similar to the present day.
Combined, field-based and isotope geochemical methods used in this study of the NW-Argentine Andes have thus helped to gain insight into the systematics, rate changes, interactions, and temporal characteristics among tectonically controlled deformation patterns, the build-up of topography impacting atmospheric processes, the distribution of rainfall, and resulting surface processes in a tectonically active mountain belt. Ultimately, this information is essential for a better understanding of the style and the rates at which non-collisional mountain belts evolve, including the development orogenic plateaus and their bordering flanks. The results presented in this study emphasize the importance of stable isotope records for paleoaltimetric and paleoenvironmental studies in mountain belts and furnishes important data for a rigorous interpretation of such records.
Straßen im Fluss
(2015)
Auch in historischer Zeit waren Straßen, Wege und Verkehrsbahnen Orte innovativer Entwicklungen der Technik, der Mobilität sowie der Infrastruktur. Anders als die ältere Forschung und populären Vorstellungen meinen, währten die Umgestaltungen der Kulturlandschaft seit dem 13. Jahrhundert bemerkenswert lange.
Diese »etwas andere« Mittelalter-Geschichte mit ihrer epochenübergreifenden Wirkung zeigt in vielen Details die vorliegende Studie. Sie schöpft aus den bewährten Methoden der Altweg-, Binnenschifffahrts- und Infrastrukturgeschichtsforschung und entdeckt dabei auf innovative Weise »Straßen im Fluss« als Modell. Mit Blick auf den Verkehrsraum zwischen Elbe und Oder – vom Spreewald über Berlin-Cölln und Brandenburg an der Havel bis nach Havelberg – gelingt erstmals eine zwischen dem mittelalterlichen Landesausbau und dem 16. Jahrhundert angesiedelte Geschichte der beiden Hauptflüsse Spree und Havel sowie ihrer Nebenläufe.
Der Autor rückt das Leben der Menschen am und auf dem Fluss ins Licht und beschreibt quellennah, wie vor allem die Städte, aber auch geistliche Institutionen wie Domstift oder Klöster an dem Wandel der Kulturlandschaft zu einem mannigfach »vernetzten« Verkehrsraum stark beteiligt waren. Die hier entwickelten Strukturen bewährten sich und besaßen Vorbildcharakter, so dass in späteren Jahrhunderten insbesondere Städte an diese mittelalterlichen Verkehrswirtschaftsprojekte anknüpften.
Lost in a liminal space?
(2015)
Analphabetismus und Teilhabe
(2015)
Aus bildungstheoretisch-gesellschaftskritischer Perspektive stellt sich Lernen als soziales Handeln in gesellschaftlich-vermittelten Verhältnissen – Möglichkeiten wie auch Begrenzungen – dar. Funktionaler Analphabetismus ist mit einem bundesweiten Anteil von 14% der erwerbsfähigen Bevölkerung oder 7,5 Millionen Analphabeten in Deutschland nicht nur ein bildungspolitisches und -praktisches, sondern auch ein wissenschaftlich zu untersuchendes Phänomen. Es gibt zahlreiche Untersuchungen, die sich mit dieser Thematik auseinandersetzen und Anknüpfungspunkte für die vorliegende Studie bieten. Aus der Zielgruppenforschung beispielsweise ist bekannt, dass die Hauptadressaten der Männer, der Älteren und der Bildungsfernen nicht adäquat erreicht bzw. als Teilnehmende gewonnen werden. Aus der Teilnehmendenforschung sind Abbrüche und Drop-Outs bekannt.
Warum Analphabeten im Erwachsenenalter, also nach der Aneignung vielfältigster Bewältigungsstrategien, durch das sich das Phänomen einer direkten Sichtbarkeit entzieht, dennoch beginnen das Lesen und Schreiben (wieder) zu lernen, wird bislang weder bildungs- noch lerntheoretisch untersucht. Im Rahmen der vorliegenden Erwachsenenbildungsstudie werden genau diese Lernanlässe empirisch herausgearbeitet.
Als Heuristik wird auf eine subjekttheoretische Theoriefolie rekurriert, die sich in besonderer Weise eignet Lernbegründungen im Kontext gesellschaftlich verhafteter Biografien sichtbar zu machen. Lernforschung im Begründungsmodell muss dabei auf eine Methodik zurückgreifen, die die Perspektive des Subjekts, Bedeutungszusammenhänge und typische Sinnstrukturen hervorbringen kann. Daher wird ein auf Einzelfallstudien basierendes, qualitatives Forschungsdesign gewählt, das Daten aus der Erhebung mittels problemzentrierter Interviews bereitstellt, die eine Auswertung innerhalb der Forschungsstrategie der Grounded Theory erfahren und in einer empirisch begründeten Typenbildung münden. Dieses Design ermöglicht die Rekonstruktion typischer Lernanlässe und im Ergebnis die Entwicklung einer gegenstandsbezogene Theorie mittlerer Reichweite.
Aus der vorliegenden Bedeutungs-Begründungsanalyse konnten empirisch fünf Lernbegründungstypen ausdifferenziert werden, die sich im Spannungsverhältnis von Teilhabeausrichtung und Widersprüchlichkeit bewegen und in ihrer Komplexität mittels der drei Schlüsselkategorien Bedeutungsraum, Reflexion der sozialen Eingebundenheit und Kompetenzen sowie Lernen bzw. dem Erleben der Diskrepanzerfahrung zwischen Lesen-Wollen und Lesen-Können dargestellt werden. Das Spektrum der Lernbegründungstypen reicht von teilhabesicherndem resignierten Lernen, bei dem die Sicherung des bedrohten Status quo im Vordergrund steht und die Welt als nicht gestaltbar erlebt wird, bis hin zu vielschichtigem teilhabeerweiternden Lernen, das auf die Erweiterung der eigenen Handlungsmöglichkeiten zielt und die umfangreichste Reflexion der sozialen Eingebundenheit und Kompetenzen aufweist. Funktionale Analphabeten begründen ihr Lernen und Nicht-Lernen vor dem Hintergrund ihrer sozialen Situation, ihrer Begrenzungen und Möglichkeiten: Schriftsprachlernen erhält erst im Kontext gesellschaftlicher Teilhabe und dessen Reflexion eine Bedeutung.
Mit der Einordnung der Lernbegründungen funktionaler Analphabeten in: erstens, Diskurse der Bildungsbenachteiligung durch Exklusionsprozesse; zweitens, die lerntheoretische Bedeutung von Inklusionsprozessen und drittens, den internationalen Theorieansatz transformativen Lernens durch die Integration der Reflexionskategorie, erfolgt eine Erweiterung bildungs- und lerntheoretischer Ansätze. In dieser Arbeit werden Alphabetisierungs- und Erwachsenen-bildungsforschung verbunden und in den jeweiligen Diskurs integriert. Weitere Anschluss- und Verwertungsmöglichkeiten in der Bildungsforschung wären denkbar. Die Untersuchung von Lernbegründungen im Längsschnitt beispielsweise kann Transformationsprozesse rekonstruierbar machen und somit Erträge für eine Bildungsprozessforschung liefern. Bildungspraktisch können die Lernbegründungstypen einerseits der Teilnehmergewinnung dienen, andererseits Ausgangspunkt für reflexive Lernbegleitungskonzepte sein, die Lernbegründungen zur Sprache bringen und die soziale Eingebundenheit thematisieren und damit Lernprozesse unterstützen.
Entlastung und Rechtsverlust
(2015)
Die Durchsetzung von Ersatzansprüchen gegenüber Vorständen, Aufsichtsräten und Geschäftsführern begegnet vielfältigen Problemen. Sie entstehen, wenn die Gesellschafter den Organmitgliedern zunächst vorbehaltlos "Entlastung" erteilen und erst im Nachhinein von Verfehlungen erfahren. Die Arbeit geht der Frage nach, in welchen Fällen die Entlastung zum Verlust von Ersatzansprüchen führt und die Haftung der Organmitglieder ausschließt.
Aufgrund zunehmender Herausforderungen bei der Entsendung von Mitarbeitern ins Ausland beschäftigt sich die Dissertation ‚Optimierung der Anzahl an Auslandsentsendungen und Empowerment of Locals in internationalen Unternehmen’ unter Zuhilfenahme der deskriptiven Entscheidungstheorie mit der wissenschaftlichen Forschungsfrage, ob sich die Anzahl der Auslandsentsendungen von deutschen Großunternehmen in den nächsten Jahren verändern wird und welche Parameter, wie z.B. die strategische Ausrichtung des Unternehmens, dafür ausschlaggebend sind. Darüber hinaus wird analysiert, inwieweit eine solche Reduzierung erfolgversprechend ist und ob es eine optimale Anzahl an Auslandsentsendungen gibt. Weiterhin wird untersucht, wie Auslandsentsendungen erfolgreich optimiert werden können und ob dies - beispielsweise durch ein gezieltes Empowerment of Locals - unterstützt werden kann. Dieses Buch richtet sich sowohl an Forschende und Studierende im Bereich der BWL – insbesondere mit den Schwerpunkten Personalmanagement und Internationales Management – als auch an HR-Mitarbeiter, Führungskräfte und Berater, die an theoretischen und empirischen Erkenntnissen zu Auslandsentsendung von Mitarbeitern und Expatriate-Management interessiert sind
The main research question of this thesis concerns the relation between focus interpretation, focus realization, and association with focus in the West Chadic language Ngamo.
Concerning the relation between focus realization and interpretation, this thesis contributes to the question, cross-linguistically, what factors influence a marked realization of the focus/background distinction. There is background-marking rather than focus-marking in Ngamo, and the background marker is related to the definite determiner in the language. Using original fieldwork data as a basis, a formal semantic analysis of the background marker as a definite determiner of situations is proposed.
Concerning the relation between focus and association with focus, the thesis adds to the growing body of crosslinguistic evidence that not all so-called focus-sensitive operators always associate with focus. The thesis shows that while the exclusive particle yak('i) (= "only") in Ngamo conventionally associates
with focus, the particles har('i) (= "even, as far as, until, already"), and ke('e) (= "also, and") do not.
The thesis provides an analysis of these phenomena in a situation semantic framework.
In this thesis we utilize resolved stellar populations to improve our understanding of galaxy formation and evolution. In the first part we improve a method for metallicity determination of faint old stellar systems, in the second and third part we analyze the individual history of six nearby disk galaxies outside the Local Group.
A New Calibration of the Color Metallicity Relation of Red Giants for HST data:
It is well known, that the color distribution of stars on the the Red Giant Branch (RGB) can be used to determine metallicities of old stellar populations that have only shallow photometry. Based on the largest sample of globular clusters ever used for such studies, we quantify the relation between metallicity and color in the widely used HST ACS filters F606W and F814W.
We use a sample of globular clusters from the ACS Globular Cluster Survey and measure their RGB color at given absolute magnitudes to derive the color-metallicity relation. We find a clear relation between metallicity and RGB color; we investigate the scatter and the uncertainties in this relation and show its limitations. A comparison with isochrones shows reasonably good agreement with BaSTI models, a small offset to Dartmouth models, and a larger offset to Padua models.
Even for the best globular cluster data available, the metallicity of a simple stellar population can be determined from the RGB alone only with an accuracy of 0.3 dex for [M/H]<-1, and 0.15 dex for [M/H]>-1. For mixed populations, as they are observed in external galaxies, the uncertainties will be even larger due to uncertainties in extinction, age, etc. Therefore caution is necessary when interpreting photometric metallicities.
The Structural History of Nearby Low Mass Disk Galaxies:
We study the individual evolution histories of three nearby, low-mass, edge-on galaxies (IC5052, NGC4244, NGC5023).
Using the color magnitude diagrams of resolved stellar populations, we construct star count density maps for populations of different ages and analyze the change of structural parameters with stellar age within each galaxy.
The three galaxies show low vertical heating rates, which are much lower than the heating rate of the Milky Way. This indicates that heating agents, as giant molecular clouds and spiral structure are weak in low mass galaxies.
We do not detect a separate thick disk in any of the three galaxies, even though our observations cover a larger range in equivalent surface brightness than any integrated light study. While scaleheights increase with age, each population can be well described by a single disk. Only two of the galaxies contain a very weak additional component, which we identify as the faint halo. The mass of these faint halos is less than 1% of the mass of the disk.
All populations in the three galaxies exhibit no or only little flaring. While this finding is consistent with previous integrated light studies, it poses strong constraints on galaxy formation models, because most theoretical simulations often find strong flaring due to interactions or radial migration.
Furthermore, we find breaks in the radial profiles of all three galaxies. The radii of these breaks are independent of age, and the break strength is decreasing with age in two of the galaxies (NGC4244 and NGC5023). This is consistent with break formation models, that combine a star formation cutoff with radial migration. The differing behavior of IC5052 can be explained by a recent interaction or minor merger.
The Structural History of Massive Disk Galaxies:
We extend the structural analysis of stellar populations with distinct ages to three massive galaxies, NGC891, NGC4565 and NGC7814. While confusion effects due to the high stellar number densities in their central region, and the prominent dust lanes inhibit an detailed analysis of the radial profiles, we can study their vertical structure.
These massive galaxies also have a slower heating than the Milky Way, comparable to the low mass galaxies. This can be traced back to their already thick young populations and thick layers of their interstellar medium.
We do not find a clear separate thick disk in any of these three galaxies; all populations can be described by a single disk plus a S\'ersic bulge/halo component. In contrast to the low mass galaxies, we cannot rule out the presence of thick disks in the massive galaxies, because of the strong influence of the halo, that might hide the possible contribution of the thick disk to the vertical star count profiles. However, the faintness of the possible thick disks still points to problems in the earlier ubiquitous findings of thick disks in external galaxies.
Die Honigbiene Apis mellifera zeigt innerhalb einer Kolonie eine an das Alter gekoppelte Arbeitsteilung. Junge Honigbienen versorgen die Brut (Ammenbienen), während ältere Honigbienen (Sammlerinnen) außerhalb des Stocks Pollen und Nektar eintragen. Die biogenen Amine Octopamin und Tyramin sind an der Steuerung der Arbeitsteilung maßgeblich beteiligt. Sie interagieren mit Zielzellen über die Bindung an G Protein gekoppelte Rezeptoren. A. mellifera besitzt fünf charakterisierte Octopaminrezeptoren (AmOctαR1, AmOctβR1-4), einen charakterisierten Tyraminrezeptor (AmTyr1) sowie einen weiteren putativen Tyraminrezeptor.
In der vorliegenden Arbeit wurde dieser putative Aminrezeptor als zweiter Tyraminrezeptor (AmTyr2) identifiziert, lokalisiert und pharmakologisch charakterisiert.
Die von der cDNA abgeleitete Aminosäuresequenz weist strukturelle Eigenschaften und konservierte Motive von G Protein gekoppelten Rezeptoren auf. Phylogenetisch ordnet sich der AmTyr2 Rezeptor bei den Tyramin 2 Rezeptoren anderer Insekten ein. Die funktionelle und pharmakologische Charakterisierung des putativen Tyraminrezeptors erfolgte in modifizierten HEK293 Zellen, die mit der Rezeptor cDNA transfiziert wurden. Die Applikation von Tyramin aktiviert Adenylylcyclasen in diesen Zellen und resultiert in einem Anstieg des intrazellulären cAMP Gehalts. Der AmTyr2 Rezeptor kann durch Tyramin in nanomolaren Konzentrationen halbmaximal aktiviert werden. Während es sich bei Octopamin um einen wirkungsvollen Agonisten des Rezeptors handelt, sind Mianserin und Yohimbin effektive Antagonisten. Für die Lokalisierung des Rezeptorproteins wurde ein polyklonaler Antikörper generiert. Eine AmTyr2-ähnliche Immunreaktivität zeigt sich im Gehirn in den optischen Loben, den Antennalloben, dem Zentralkomplex und in den Kenyon Zellen der Pilzkörper.
Des Weiteren wurde die Rolle der Octopamin- und Tyraminrezeptoren bei der Steuerung der altersabhängigen Arbeitsteilung analysiert.
Die Genexpression des AmOctαR1 in verschiedenen Gehirnteilen korreliert unabhängig vom Alter mit der sozialen Rolle, während sich die Genexpression von AmOctβR3/4 und den Tyraminrezeptoren AmTyr1 und AmTyr2 maximal mit dem Alter aber nicht der sozialen Rolle ändert. Sammlerinnen weisen einen höheren Octopamingehalt im Gesamtgehirn auf als Ammenbienen; bei Tyramin zeigen sich keine Unterschiede. Während Tyramin offensichtlich keine direkte Rolle spielt, werden durch Octopamin gesteuerte Prozesse der altersabhängigen Arbeitsteilung bei der Honigbiene vermutlich über den AmOctαR1 vermittelt.
Die Ergebnisse der vorliegenden Arbeit zeigen die wichtige Rolle von biogenen Aminen, insbesondere Octopamin bei der sozialen Organisation von Insektenstaaten.
Fiktion im Historischen
(2015)
Lucans unter Nero entstandenes Epos über den römischen Bürgerkrieg zielt weniger auf eine historisch korrekte Darstellung ab als auf eine Deutung in weitaus größerem Maße. Dafür bricht der Autor mit üblichen Gattungskonventionen, obwohl er typische Elemente des Genres nutzt. Entscheidend für das Verständnis ist die Bildsprache mit ihren Gleichnissen, Kurzvergleichen, Metaphern und Exempla, die bisher zu wenig Beachtung fanden und im Anhang erstmals vollständig erfaßt sind. So gleicht etwa Crassus einem “Isthmus”, der Caesar und Pompeius trennt, der alternde Pompeius einer “stürzenden Eiche” oder Caesar durch sein schnelles entschiedenes Handeln einem “Blitz”. Solche Formen werden planvoll eingesetzt und verknüpft, um die zentrale Rolle der Akteure im Bürgerkrieg zu kommunizieren. Dabei kommt Caesar, Pompeius, Cato, den Soldaten, dem Volk und einigen Nebenfiguren mehr Bedeutung zu als in anderen Berichten und epischen Prätexten. Der Blick des Lesers soll weniger auf das Geschehen als auf das Verhalten der Menschen gelenkt werden, wozu einzelne Geschehensabläufe auffallend anders als in anderen Quellen gewichtet und gestaltet sind.
Die Dissertation mit dem Thema „Demografie und politischer Reduktionismus – eine Diskursanalyse der Demografiepolitik in Deutschland“ knüpft an die Debatte um die Demografisierung an, die sich damit beschäftigt, dass gesellschaftliche Entwicklungen häufig zu sehr aus einer demografischen Perspektive betrachtet und beschrieben werden. Sie analysiert die zum Teil noch jungen Diskurse, die durch Akteure in Wissenschaft, Politik und Publizistik zu den demografiepolitischen Strategien und Aktivitäten der Bundesregierung geführt werden.
Dabei werden Teilbereiche der Gesellschaft, darunter insbesondere die soziale Sicherung, die Generationenbeziehungen sowie die ökonomische Entwicklung und auch räumliche Aspekte der Demografie, in den Blick genommen. Es werden ausgewählte Zusammenhänge zwischen gesellschaftlichen Entwicklungen und demografischen Veränderungen reflektiert, denen ein kausales Beziehungsverhältnis bescheinigt wird. Es wird aufgezeigt, wo mit Verweis auf die Demografie lediglich Deutungsangebote geschaffen und Kausalbehauptungen aufgestellt werden.
Von besonderem Untersuchungsinteresse ist hierbei die Demografie als Argument, um politisches, wirtschaftliches und soziales Handeln zu legitimieren und ein gesellschaftliches Klima der Akzeptanz zu erzeugen. Wo erweist sich die Demografie als ein Spekulationsobjekt – wo ist sie erwiesene, überprüfbare Kausalität? Und wo ist die Grenze zur Instrumentalisierung der Demografie zu ziehen? Es wird belegt, dass eine Gelegenheitsdemografie vor allem aus drei Gründen praktiziert wird: Sie verschafft organisierten Interessen Gehör, sie bietet Orientierung in komplexen Gesellschaften und sie dient als Beurteilungsmaßstab der Bewertung von gesellschaftlichen Entwicklungen.
Die aktuelle Konjunktur von Diskursen zum demografischen Wandel sorgt dafür, dass die Gelegenheiten, mit Demografie zu argumentieren, immer wieder reproduziert werden. In der Folge werden nicht nur gesellschaftliche Entwicklungen zu sehr auf demografische Komponenten zurückgeführt. Auch das familien-, sozial-, migrations- und wirtschaftspolitische Denken und Handeln wird häufig über das Maß tatsächlicher Ursache-Wirkungs-Zusammenhänge hinaus auf vermeintliche demografische Gesetzmäßigkeiten reduziert (Reduktionismus).
Die Diskursanalyse der Demografiepolitik in Deutschland will die Bedeutung des demografischen Wandels für die Gesellschaft dabei nicht in Frage stellen. Sie soll für einen kritischeren Umgang mit der Demografie sensibilisieren. Dazu gehört auch, aufzuzeigen, dass die Demografie ein Faktor unter vielen ist.
This thesis investigates the application of polyelectrolyte multilayers in plasmonics and picosecond acoustics. The observed samples were fabricated by the spin-assisted layer-by-layer deposition technique that allowed a precise tuning of layer thickness in the range of few nanometers.
The first field of interest deals with the interaction of light-induced localized surface plasmons (LSP) of rod-shaped gold nanoparticles with the particles' environment. The environment consists of an air phase and a phase of polyelectrolytes, whose ratio affects the spectral position of the LSP resonance.
Measured UV-VIS spectra showed the shift of the LSP absorption peak as a function of the cover layer thickness of the particles. The data are modeled using an average dielectric function instead of the dielectric functions of air and polyelectrolytes. In addition using a measured dielectric function of the gold nanoparticles, the position of the LSP absorption peak could be simulated with good agreement to the data.
The analytic model helps to understand the optical properties of metal nanoparticles in an inhomogeneous environment.
The second part of this work discusses the applicability of PAzo/PAH and dye-doped PSS/PAH polyelectrolyte multilayers as transducers to generate hypersound pulses. The generated strain pulses were detected by time-domain Brillouin scattering (TDBS) using a pump-probe laser setup. Transducer layers made of polyelectrolytes were compared qualitatively to common aluminum transducers in terms of measured TDBS signal amplitude, degradation due to laser excitation, and sample preparation.
The measurements proved that fast and easy prepared polyelectrolyte transducers provided stronger TDBS signals than the aluminum transducer. AFM topography measurements showed a degradation of the polyelectrolyte structures, especially for the PAzo/PAH sample.
To quantify the induced strain, optical barriers were introduced to separate the transducer material from the medium of the hypersound propagation. Difficulties in the sample preparation prohibited a reliable quantification. But the experiments showed that a coating with transparent polyelectrolytes increases the efficiency of aluminum transducers and modifies the excited phonon distribution.
The adoption of polyelectrolytes to the scientific field of picosecond acoustics enables a cheap and fast fabrication of transducer layers on most surfaces. In contrast to aluminum layers the polyelectrolytes are transparent over a wide spectral range. Thus, the strain modulation can be probed from surface and back.
Symbolische Bedeutungen sind für den Erfolg von Marken heutzutage unerlässlich, denn Produkte lassen sich in postmodernen Konsumgesellschaften meist nicht mehr ausschließlich durch funktionale Leistungsunterschiede vom Wettbewerb differenzieren. Vielmehr sollten Marken zudem über einen signifikanten Zusatznutzen verfügen, welcher grundsätzlich sozialpsychologischer Natur ist. Dieser in der Markenpersönlichkeit verdichtete symbolische Kern spricht die zentralen menschlichen Bedürfnisse nach Selbstdefinition und Selbstausdruck an, da Individuen sich als „soziale Tiere“ grundlegend über die Zugehörigkeit zu sozialen Gruppen definieren. Einstellungen relevanter Bezugspersonen zum eigenen Selbstbild sind fundamental für die persönliche Standortbestimmung. Genauso leiten Konsumenten symbolische Markenbedeutungen von ihren Bezugsgruppen ab. Individuen evaluieren demnach permanent, inwiefern die wahrgenommene Markenpersönlichkeit zum aktuellen bzw. angestrebten Selbstkonzept passt. Diese dargestellten Phänomene unterliegen dem kulturellen Einfluss der jeweiligen Gesellschaft, in der sie sich herausbilden. Die symbolischen Bedeutungen von Selbstbildern und Marken formen sich also zwischen Kulturen bspw. unter unterschiedlich stark geartetem sozialem Einfluss.
Die Untersuchung geht demnach der Frage auf den Grund, inwiefern die soziale Umgebung Einfluss auf die Wahrnehmung symbolischer Markenaspekte und deren wahrgenommener Kongruenz zum Selbstkonzept von Konsumenten ausübt. Darüber hinaus eruiert der Verfasser intensiv, ob und in welchem Umfang die Empfänglichkeit für die verschiedenen Facetten sozialen Einflusses von der Enkulturation des Konsumenten abhängt.
Es werden somit Forderungen aus Marketing- und Konsumentenverhaltensforschung adressiert, wonach die sozialen sowie die kulturellen Einflusskomponenten stärker zu berücksichtigen sind, um ein vollständigeres Bild von Konsumentscheidungen zu erlangen.
Die zahlreichen theoretischen und empirischen Erkenntnisse der Studie weisen auf wichtige Implikationen für die intra- und interkulturelle Segmentierung von Zielgruppen hin. Empfehlungen für die strategische Positionierung von symbolischen Markenkernen und deren Kommunikation werden ebenfalls geliefert.
Das Schulbuch ist ein etablierter und bedeutender Bestandteil des Mathematikunterrichts. Lehrer nutzen es, um ihren Unterricht vorzubereiten und/oder zu gestalten; Schüler, um in selbigem zu lernen und zu bestehen, vielleicht sogar aus eigenem Interesse; Eltern, um sich darüber zu informieren, was ihr Kind eigentlich können soll und wie sie ihm gegebenenfalls helfen können. Darüber hinaus ist das Schulbuch ein markantes gesellschaftliches Produkt, dessen Zweck es ist, das Unterrichtsgeschehen zu steuern und zu beeinflussen. Damit ist es auch ein Anzeiger dafür, was und wie im Mathematikunterricht gelehrt werden sollte und wird. Die Lehrtexte als zentrale Bestandteile von Schulbüchern verweisen in diesem Zusammenhang insbesondere auf die Phasen der Einführung neuen Lernstoffs. Daraus legitimiert sich übergreifend die Fragestellung, was und wie (gut) Mathematikschulbuchlehrtexte lehren bzw. was und wie (gut) adressierte Schüler aus ihnen (selbstständig) lernen, d.h. Wissen erwerben können.
Angesichts der komplexen und vielfältigen Bedeutung von Schulbuchlehrtexten verwundert es, dass die mathematikdidaktische Forschung bislang wenig Interesse an ihnen zeigt: Es fehlen sowohl eine theoretische Konzeption der Größe ‚Lehrpotential eines schulmathematischen Lehrtextes‘ als auch ein analytisches Verfahren, um das anhand eines Mathematikschulbuchlehrtextes Verstehbare und Lernbare zu ermitteln. Mit der vorliegenden Arbeit wird sowohl in theoretisch-methodologischer als auch in empirischer Hinsicht der Versuch unternommen, diesen Defiziten zu begegnen. Dabei wird das ‚Lehrpotential eines Mathematikschulbuchlehrtextes‘ auf der Grundlage der kognitionspsychologischen Schematheorie und unter Einbeziehung textlinguistischer Ansätze als eine textimmanente und analytisch zugängliche Größe konzipiert. Anschließend wird das Lehrpotential von fünf Lehrtexten ausgewählter aktueller Schulbücher der Jahrgangsstufen 6 und 7 zu den Inhaltsbereichen ‚Brüche‘ und ‚lineare Funktionen‘ analysiert. Es zeigt sich, dass die untersuchten Lehrtexte aus deutschen Schulbüchern für Schüler sehr schwer verständlich sind, d.h. es ist kompliziert, einigen Teiltexten im Rahmen des Gesamttextes einen Sinn abzugewinnen. Die Lehrtexte sind insbesondere dann kaum sinnhaft lesbar, wenn ein Schüler versucht, die mitgeteilten Sachverhalte zu verstehen, d.h. Antworten auf die Fragen zu erhalten, warum ein mathematischer Sachverhalt gerade so und nicht anders ist, wozu ein neuer Sachverhalt/Begriff gebraucht wird, wie das Neue mit bereits Bekanntem zusammenhängt usw. Deutlich zugänglicher und sinnhafter erscheinen die Mathematikschulbuchlehrtexte hingegen unter der Annahme, dass ihre zentrale Botschaft in der Mitteilung besteht, welche Aufgabenstellungen in der jeweiligen Lehreinheit vorkommen und wie man sie bearbeitet. Demnach können Schüler anhand dieser Lehrtexte im Wesentlichen lernen, wie sie mit mathematischen Zeichen, die für sie kaum etwas bezeichnen, umgehen sollen. Die hier vorgelegten Analyseergebnisse gewinnen in einem soziologischen Kontext an Tragweite und Brisanz. So lässt sich aus ihnen u.a. die These ableiten, dass die analysierten Lehrtexte keine ‚unglücklichen‘ Einzelfälle sind, sondern dass die ‚Aufgabenorientierung in einem mathematischen Gewand‘ ein Charakteristikum typischer (deutscher) Mathematikschulbuchlehrtexte und – noch grundsätzlicher – einen Wesenszug typischer schulmathematischer Kommunikation darstellt.