Refine
Year of publication
- 2017 (181) (remove)
Document Type
- Doctoral Thesis (181) (remove)
Language
- English (181) (remove)
Is part of the Bibliography
- yes (181) (remove)
Keywords
- Klimawandel (4)
- climate change (4)
- Arbeitsmarktpolitik (2)
- Bioraffinerie (2)
- DNA origami (2)
- Epidemiologie (2)
- Innovationsmanagement (2)
- Machine Learning (2)
- Nanopartikel (2)
- Naturgefahren (2)
- Netzwerke (2)
- Prosodie (2)
- Zeitreihenanalyse (2)
- biomass (2)
- coordination (2)
- entrepreneurship (2)
- language production (2)
- nanoparticles (2)
- natural hazards (2)
- networks (2)
- numerical modeling (2)
- numerische Modellierung (2)
- prosody (2)
- self-assembly (2)
- "Reactive Flux" Ratenkonstanten (1)
- 2-Thiodisaccharide (1)
- 2-Thiodisaccharides (1)
- 3D Modellierung (1)
- 3D geovirtual environment (1)
- 3D geovisualization system (1)
- 3D-Geovisualisierungssystem (1)
- 3D-geovirtuelle Umgebung (1)
- 3D-modeling (1)
- Abhängigkeit (1)
- Adipositas (1)
- Aggression (1)
- Aktivierungsentropie (1)
- Akzeptabilitätsbewertung (1)
- Anregungs-Abfrage-Experiment (1)
- Antibiotika (1)
- Antiferromagnetismus (1)
- Arbeitslosenversicherung (1)
- Arbeitslosigkeit (1)
- Arbeitssuche (1)
- Arbeitssuchverhalten (1)
- Arktik (1)
- Artverbreitung (1)
- Asteroseismologie (1)
- Atmosphärendynamik (1)
- Aufarbeitung von Fruktose (1)
- Ausdauerleistung (1)
- Australia (1)
- Australien (1)
- Automatisierung (1)
- Autotrophie (1)
- Azobenzol (1)
- Azobenzol-haltiges Tensid (1)
- Bachstufen (1)
- Bakterien Sensor (1)
- Beobachtung anthropogener Aktivitäten (1)
- Beobachtung von Erdbebenquellen (1)
- Betriebswirtschaft (1)
- Bioinformatik (1)
- Biomasse (1)
- Biorefinery (1)
- Biosensoren (1)
- Biosynthese (1)
- Blockcopolymervesikel (1)
- Bohrlochrandausbrüche (1)
- Borel Funktionen (1)
- Borel functions (1)
- Brand Equity (1)
- Brand Management (1)
- Brechungsindex von Azobenzol-haltigen Tensiden (1)
- Business Development (1)
- Canada (1)
- Catalysis (1)
- Cauchy horizon (1)
- Cauchyhorizont (1)
- Cer Ammonium Nitrat (CAN) (1)
- Ceric Ammonium Nitrate (CAN) (1)
- Chemodynamik der Milchstraße (1)
- Cherenkov showers (1)
- Cherenkov-Schauern (1)
- Closure Positive Shift (CPS) (1)
- Coarea Formel (1)
- Constraint-basierte Modellierung (1)
- Cre Rekombinase (1)
- Cre recombinase (1)
- Cyanobakterien (1)
- DFTB3 (1)
- DNA Origami (1)
- DNA assembly (1)
- DNA damage (1)
- DNA-Origami (1)
- DNA-Schädigung (1)
- DNS Assemblierung (1)
- Dark Matter (1)
- Datenintegration (1)
- Datenqualität (1)
- Deep Learning (1)
- Design Thinking (1)
- Deutschland (1)
- Diabetes mellitus Typ 2 (1)
- Dichteheterogenitäten im oberen Mantel (1)
- Dihydroxyaceton (1)
- Discrimination Networks (1)
- Diversität (1)
- Dokument Analyse (1)
- Doppelsterne (1)
- Doppelt hydrophile Blockcopolymere (1)
- Dreisprachigkeit (1)
- Dunkler Materie (1)
- Duplikaterkennung (1)
- E-Learning (1)
- ECIS (1)
- EM (1)
- Eisenbahninfrastruktur (1)
- El`gygytgyn Kratersee (1)
- Elektromyographie (1)
- Ellipse (1)
- El’gygytgyn Crater Lake (1)
- Empfehlungen (1)
- Entdeckung (1)
- Entrepreneurship (1)
- Entstehung der Milchstraße (1)
- Entstehung von Galaxien (1)
- Entwicklung (1)
- Entwicklung von Galaxien (1)
- Erdbeben Modellierung (1)
- Ereigniskorrelierte Hirnpotentiale (EKP) (1)
- Ernährung (1)
- Ernährungsmuster (1)
- Erosion (1)
- European bats (1)
- Europäische Fledermausarten (1)
- Eutrophierung (1)
- Evolutionsgenetik (1)
- FRET (1)
- Feinsedimente (1)
- Ferromagnetismus (1)
- Festigkeit des Schiefer (1)
- Fettoxidation (1)
- Fettstoffwechsel (1)
- FhuA (1)
- Finanzwissenschaften (1)
- Flocking (1)
- Fluoreszenz (1)
- Fokus (1)
- Fotoschalter (1)
- Förster resonance energy transfer (1)
- Förster-Resonanzenergietransfer (1)
- GIS (1)
- GIS-Dienstkomposition (1)
- GTPase (1)
- Galaxien (1)
- Galaxien: Evolution (1)
- Galaxien: Kinematik und Dynamik (1)
- Galaxien: Statistiken (1)
- Gator Netzwerk (1)
- Gator networks (1)
- Gebirgsbäche (1)
- Geographical mobility (1)
- Geomorphologie (1)
- Geothermie (1)
- Gerinne-Hang-Kopplung (1)
- German (1)
- Germany (1)
- Geschiebetransport (1)
- Geschmackssystems (1)
- Gewinnung benannter Entitäten (1)
- Gleichgewicht (1)
- Gleichgewichtstraining (1)
- Goldnanopartikel (1)
- Gravitationswelle (1)
- Grundwasser (1)
- Gründungsförderung (1)
- Gründungszuschuss (1)
- Hitzewellen (1)
- Hohlzylinderversuche (1)
- Huftiere (1)
- Hybrid (1)
- Hybridmodell (1)
- Hydroxymethylfurfural (1)
- IC Model (1)
- IC Modell (1)
- Iceland (1)
- Information Retrieval (1)
- Informationsextraktion (1)
- Inklusionsabhängigkeit (1)
- Innovation (1)
- Innovation Management (1)
- Inversions-Theorie (1)
- Island (1)
- Jetstream (1)
- Job search behavior (1)
- Kaffee (1)
- Kanada (1)
- Katalyse (1)
- Kenias öffentlicher Dienst (1)
- Kenya public service (1)
- Kerguelen (1)
- Kern Methoden (1)
- Ketzin (1)
- Kindheit (1)
- Kinematik (1)
- Klimafolgenanalyse (1)
- Kohlenhydrat-Protein Interaction (1)
- Kohlenhydrate (1)
- Kohlenhydratoxidation (1)
- Kohlenstoff (1)
- Kohlenstoff-Nanopunkte (1)
- Kohlenstoff-Punkte (1)
- Kohlenstoffisotope (1)
- Kohlenstoffnitride (1)
- Komposite (1)
- Konformationsselektion (1)
- Koordination (1)
- Koordinationskomplexe (1)
- Koordinierung (1)
- Krafttraining (1)
- Kultur (1)
- Küste (1)
- L2 sentence processing (1)
- Labor market policies (1)
- Ladung Transport (1)
- Ladungsträgerrekombination (1)
- Landformen (1)
- Landschaftsanalyse (1)
- Landschaftspräferenzen (1)
- Lawinen (1)
- Leerlaufspannung (1)
- Leistungsinformationen verwenden (1)
- Leistungsmanagement (1)
- Leseexperiment (1)
- Licht (1)
- Lignin (1)
- Line Suche (1)
- Litoral (1)
- Lumping (1)
- Lysimeter (1)
- Längsschnitt (1)
- Lösungsmitteleffekte (1)
- Lösungsprozess (1)
- Magnetosomen-Ketten (1)
- Makrophyten (1)
- Mantleplumes (1)
- Markenführung (1)
- Markenwert (1)
- Marketing Strategy (1)
- Markov state models (1)
- Markowketten (1)
- Maximalkraft/Schnellkraft (1)
- Mediationsanalyse (1)
- Meeres-Governance (1)
- Mehrsprachigkeit (1)
- Mesokristalle (1)
- Message Passing Interface (1)
- Metabolomics (1)
- Metadaten (1)
- Metanome (1)
- Microdialyse (1)
- Microeconometrics (1)
- Microviridin (1)
- Middleware (1)
- Mikrobiologie (1)
- Mikroökonometrie (1)
- Milky Way chemodynamics (1)
- Milky Way evolution (1)
- Minimax Optimalität (1)
- Mobil (1)
- Modellierung des seismischen Zyklus (1)
- Mongolei (1)
- Mongolia (1)
- N-Alkylglycin (1)
- N-alkyl-glycine (1)
- NGS (1)
- NLME (1)
- NLP (1)
- Nachkommen (1)
- Nanolinsen (1)
- Naturrisiken (1)
- Naturschutz (1)
- Naturstoffe (1)
- Navier-Stokes-Gleichungen (1)
- Navier-Stoks equations (1)
- Neo-institutionalismus (1)
- Nettoproduktion (1)
- Nettorotation der Lithosphäre (1)
- Niederschlag (1)
- Normalenbündel (1)
- Norwegian (1)
- Norwegisch (1)
- Nucleus parabrachialis (1)
- OLED (1)
- Oberflächenwasser-Grundwasser Interaktion (1)
- Objekttopikalisierung (1)
- Ontologien (1)
- Optimierung von Biosynthesewegen (1)
- Optogenetik (1)
- Organisationsreform (1)
- Organisationstheorie (1)
- Organizational innovation (1)
- Oxo-Kohlenstoff (1)
- PBPK (1)
- PPGIS (1)
- Partikelverben (1)
- Periphyton (1)
- Permafrost (1)
- Personal Data (1)
- Pflanzen-Habitat Interaktionen (1)
- Pharmakodynamik (1)
- Photochemie (1)
- Photogrammetrie (1)
- Photokatalyse (1)
- Phylogeographie (1)
- Plasmonik (1)
- Plattenbewegungen (1)
- Plume-Rücken Interaktion (1)
- Polyester (1)
- Polykondensation (1)
- Polymerchemie (1)
- Polymere (1)
- Polymersynthese (1)
- Polypeptoide (1)
- Populations Analyse (1)
- Populationsökologie (1)
- Posidonia shale (1)
- Posidonienschiefer (1)
- Privatsphäre (1)
- Product Scandals (1)
- Profilerstellung für Daten (1)
- Protease-Inhibitoren (1)
- Protein-Polymer Konjugaten (1)
- Protein-Protein-Interaktion (1)
- Proteinkinetik (1)
- Prozessidentifikation (1)
- Prozesssynchronisierung (1)
- Psycholinguistik (1)
- QM/MM Molekulardynamik (1)
- QM/MM stochastic dynamics (1)
- Quadratsäure (1)
- Quantenchemie (1)
- RAFT/MADIX Polymerisation (1)
- RAFT/MADIX polymerization (1)
- ROP (1)
- ROS (1)
- Radarinterferometrie mit synthetischer Apertur (1)
- Radikalreaktionen (1)
- Radiokarbon (1)
- Radiosensitization (1)
- Rauheit (1)
- Raumwellen (1)
- Reaktionsmechanismen (1)
- Regionale Mobilität (1)
- Regionalökonometrie (1)
- Regionalökonomie (1)
- Reibung an Plattengrenzen (1)
- Rektifizierbarkeit höherer Ordnung (1)
- Reptilien (1)
- Rete Netzwerk (1)
- Rete networks (1)
- RiPP (1)
- Ringöffnungspolymerisation (1)
- Rubisco (1)
- Rumpfkinematik (1)
- Rumpfkraft (1)
- Réunion (1)
- SERS (1)
- Satellitenbilder (1)
- Satzverarbeitung (1)
- Schadensmodellierung (1)
- Schnittstelle (1)
- Scrambling (1)
- Sedimentfracht (1)
- Sedimentquellenidentifizierung (1)
- Seen (1)
- Seismizität und Tektonik (1)
- Selbstassemblierung (1)
- Selbstorganisation (1)
- Senioren (1)
- Serviceorientierte Architektur (SOA) (1)
- Silbernanopartikel (1)
- Skelettmuskel (1)
- Software-basierte Cache-Kohärenz (1)
- Southeast Asia (1)
- Spannung (1)
- Spannungsänderungen (1)
- Spektralanalyse (1)
- Spektroskopie (1)
- Spillover Effects (1)
- Spracherkennung (1)
- Spracherwerb (1)
- Sprachinhibition (1)
- Sprachproduktion (1)
- Sprachwahrnehmung (1)
- Sprachwechsel (1)
- Standard (1)
- Staufen im Breisgau (1)
- Sternentwicklung (1)
- Sternwinde (1)
- Stoffwechselnetze (1)
- Strategisches Management (1)
- Städe (1)
- Städte Effizienz (1)
- Subduktion (1)
- Subjective beliefs (1)
- Subjektive Erwartungen (1)
- Surface Hopping Dynamik (1)
- Syntax (1)
- Systemsbiologie (1)
- Säuglinge (1)
- Südostasien (1)
- Talsperre (1)
- Teile und Herrsche (1)
- Telekonnektionen (1)
- Temperatur (1)
- Temporäre Ambiguität (1)
- Theory of Mind (1)
- Thermoregulationsverhalten (1)
- Tiefe Biosphäre (1)
- Transkriptionsfaktor (1)
- Transmembranprotein (1)
- Trendanalysen (1)
- Typ-2-Diabetes mellitus (1)
- UHI (1)
- Unternehmensführung (1)
- Untertage-Kohlevergasung (1)
- Upgrade of Fructose (1)
- VERITAS (1)
- Variabilität (1)
- Verhalten (1)
- Verwaltungsmodernisierung (1)
- Viskositätsstruktur im oberen Mantel (1)
- Vollkorn (1)
- Vorhersagemodelle (1)
- Wasserhaushalt (1)
- Wellenbrechung und Diffraktion (1)
- Wellengleichung (1)
- Wetterlagen (1)
- Wirbelsäule (1)
- Wirkstoffinteraktionen (1)
- Wissen (1)
- Wissenschaftlichesworkflows (1)
- Wolf-Rayet (1)
- Wärmetransport (1)
- Wüste (1)
- Zeitreihenuntersuchung (1)
- Zeitskala (1)
- Zell Bewegung (1)
- Zell-substrat Adhäsion (1)
- Zweisprachigkeit (1)
- absorptive capacity (1)
- acceptability judgments (1)
- activated urethane (1)
- activation entropy (1)
- aggression (1)
- agrammatic aphasia (1)
- agricultural production systems (1)
- agronomic factors (1)
- aktiviertes Urethan (1)
- aldehyde (1)
- anger regulation (1)
- annotation (1)
- antecedent complexity (1)
- antibiotic combinations (1)
- antiferromagnetism (1)
- approximate differentiability (1)
- approximative Differenzierbarkeit (1)
- arctic (1)
- argument mining (1)
- argumentation (1)
- argumentation mining (1)
- argumentation structure (1)
- argumentation structure parsing (1)
- asteroseismology (1)
- asymmetric competition (1)
- asymmetrische Konkurrenz (1)
- atmosphere dynamics (1)
- automatic classification (1)
- automation (1)
- automatische Klassifizierung (1)
- autotrophy (1)
- azobenzene (1)
- azobenzene refractive index (1)
- azobenzene surfactant (1)
- bacterial population growth (1)
- bacterial sensor (1)
- balance (1)
- balance training (1)
- bedload transport (1)
- behaviour (1)
- benthic primary producers (1)
- benthische Primärproduzenten (1)
- bifunctional enzyme (1)
- bildbasierte Repräsentation (1)
- bilingualism (1)
- binary stars (1)
- bioenergy (1)
- biogeography (1)
- bioinformatics (1)
- biomass flows (1)
- biophysics (1)
- biorefinery (1)
- biosensors (1)
- biosynthesis (1)
- block copolymer vesicles (1)
- body waves (1)
- borehole breakouts (1)
- business support (1)
- carbohydrate oxidation (1)
- carbohydrate-protein interaction (1)
- carbohydrates (1)
- carbon (1)
- carbon dots (1)
- carbon isotopes (1)
- carbon nanodots (1)
- carbon nitrides (1)
- catalytic azobenzene isomerization (1)
- cell movement (1)
- cell-substrate adhesion (1)
- channel steps (1)
- channel-hillslope coupling (1)
- charge carrier recombination (1)
- charge transport (1)
- childhood (1)
- chloro-ribosome (1)
- cities (1)
- climate impact analysis (1)
- coarea formula (1)
- coast (1)
- coffee (1)
- coherence (1)
- communities (1)
- composite materials (1)
- computational seismology (1)
- computergestützte Seismologie (1)
- conformational selection (1)
- conservation (1)
- constraint-based modeling (1)
- contrastive topic (1)
- controlled radical polymerization (1)
- conventional agriculture (1)
- coordination complexes (1)
- cosmological simulations (1)
- culture (1)
- cyanobacteria (1)
- damage modeling (1)
- das Cauchyproblem (1)
- das Goursatproblem (1)
- das charakteristische Cauchyproblem (1)
- data integration (1)
- data profiling (1)
- data quality (1)
- deep biosphere (1)
- deep learning (1)
- degradation (1)
- demografischer Wandel (1)
- demographic change (1)
- dependency (1)
- der Städtische Wärmeinseleffekt (1)
- der Urbane Hitzeinsel Effekt (1)
- der Urbane Hitzeinsel Effekt basierend auf Landoberflächentemperatur (1)
- desert (1)
- development (1)
- die Stadtform (1)
- die linearisierte Einsteingleichung (1)
- dihydroxyacetone (1)
- discourse parsing (1)
- discourse structure (1)
- discovery (1)
- discrimination networks (1)
- dissociative electron attachment (1)
- dissoziative Elektronen Anlagerung (1)
- diversity (1)
- divide-and-conquer (1)
- document analysis (1)
- double hydrophilic block copolymers (1)
- drug drug interactions (1)
- duplicate detection (1)
- dynamic topography (1)
- dynamische Topographie (1)
- earthquake modeling (1)
- earthquake source observations (1)
- ecological modelling (1)
- eindeutige Spaltenkombination (1)
- einseitige Kommunikation (1)
- elderly (1)
- electrical chemotaxis assay (1)
- electromyography (1)
- elektrischer Chemotaxis Assy (1)
- ellipsis (1)
- elliptic quasicomplexes (1)
- elliptische Quasi-Komplexe (1)
- energy efficiency (1)
- epidemiology (1)
- equatorial electrojet (1)
- erosion (1)
- estuary (1)
- event-related potentials (ERP) (1)
- evolutionary history (1)
- exercise performance (1)
- exercise supervision (1)
- fat oxidation (1)
- ferromagnetism (1)
- flocking (1)
- fluorescence (1)
- flussunterbrechende Analyse (1)
- focus (1)
- freshwater ecosystems (1)
- functional dependency (1)
- funktionale Abhängigkeit (1)
- fusion (1)
- galactic astronomy (1)
- galactolipids (1)
- galaktische Astrophysik (1)
- galaxies: evolution (1)
- galaxies: kinematics and dynamics (1)
- galaxies: statistics (1)
- galaxy (1)
- galaxy evolution (1)
- galaxy formation (1)
- garden path (1)
- gelöster organischer Kohlenstoff (1)
- geodynamic models (1)
- geodynamische Modelle (1)
- geomechanical modelling (1)
- geomechanische Modellierung (1)
- geomorphology (1)
- geospatial services (1)
- geothermal (1)
- giant unilamellar vesicles (1)
- gold nanoparticles (1)
- grafische Modelle (1)
- graphical models (1)
- gravitational wave (1)
- groundwater (1)
- heat transport (1)
- heatwaves (1)
- high quantum yield (1)
- high resolution mass spectrometry (1)
- higher order rectifiability (1)
- hochauflösende Massenspektrometrie (1)
- hohe Quantenausbeute (1)
- hollow cylinder experiments (1)
- hybrid (1)
- hybrid model (1)
- hybrid multi-junction solar cell (1)
- hybride Mehrschichtsolarzellen (1)
- hyporheic zone (1)
- hyporheische Zone (1)
- image-based representation (1)
- importance sampling (1)
- inclusion dependency (1)
- incremental graph pattern matching (1)
- individual anaerobic threshold (1)
- individuelle anaerobe Schwelle (1)
- induced fit (1)
- induced seismicity (1)
- induzierte Passform (1)
- induzierte Seismizität (1)
- infants (1)
- inflectional morphology (1)
- information extraction (1)
- inkrementelle Graphmustersuche (1)
- innovation adoption (1)
- innovation management (1)
- interdepartmental committee (1)
- interface (1)
- intermediaries (1)
- interministerielle Arbeitsgruppe (1)
- interspecific interactions (1)
- interspezifische Wechselwirkungen (1)
- inverse Probleme (1)
- inverse problems (1)
- inverse theory (1)
- jet stream (1)
- job search (1)
- katalytische Isomerisation von Azobenzolen (1)
- kernel methods (1)
- kinematics (1)
- knowledge (1)
- kontrastives Topik (1)
- kontrollierte radikalische Polymerisationen (1)
- konventionelle Landwirtschaft (1)
- kosmologische Simulationen (1)
- labor market policy (1)
- lakes (1)
- landforms (1)
- landscape preferences (1)
- landscape analysis (1)
- language acquisition (1)
- language inhibition (1)
- language recognition (1)
- language switching (1)
- light (1)
- line search (1)
- lipid metabolism (1)
- lithosphere net rotation (1)
- lithosphere stress field (1)
- lithosphärisches Spannungsfeld (1)
- littoral eutrophication (1)
- local and regional factors (1)
- longitudinal methodology (1)
- lower critical solution temperature (1)
- lower extremity muscle strength/power (1)
- lumping (1)
- lunar tides (1)
- lunare Gezeiten (1)
- lysimeter (1)
- machine learning (1)
- macrophytes (1)
- magnetische resonante Beugung (1)
- magnetischer Zirkulardichroismus (1)
- magnetosome chains (1)
- magnetotactic bacteria (1)
- magnetotaktische Bakterien (1)
- mantle plumes (1)
- marine governance (1)
- maschinelle Verarbeitung natürlicher Sprache (1)
- massereiche Sterne (1)
- massive stars (1)
- maternal diet (1)
- maternale Ernährung (1)
- mathematical modelling (1)
- mathematische Modellierung (1)
- mechanistic modeling (1)
- mechanistische Modellierung (1)
- mechanobiology (1)
- mediation analysis (1)
- mental number representation (1)
- mentale Zahlenrepräsentation (1)
- mesocrystals (1)
- metabolic networks (1)
- metabolomics (1)
- metadata (1)
- metanome (1)
- microbial decomposition (1)
- microbiology (1)
- microdialysis (1)
- microeconometric analyses (1)
- microviridin (1)
- microwave synthesis (1)
- middleware (1)
- mikrobieller Abbau (1)
- mikrowellengestützte Synthese (1)
- mikrökonometrische Analysen (1)
- minimax optimality (1)
- mitochondrial transformation (1)
- mixed methods (1)
- mobile (1)
- mock observations (1)
- model-driven software engineering (1)
- modellgetriebene Softwareentwicklung (1)
- monitoring of anthropogenic activities (1)
- morphological changes (1)
- morphologischen Veränderungen (1)
- mountain rivers (1)
- multilingualism (1)
- nachaltige Städteentwicklung (1)
- named entity mining (1)
- nanolenses (1)
- nanoporous carbon particles (1)
- nanoporöser Kohlenstoffpartikel (1)
- natural language processing (1)
- natural products (1)
- natural risks (1)
- natürliche Sprachverarbeitung (1)
- net production (1)
- nicht-lineare gemischte Modelle (NLME) (1)
- nicht-monetäre Bewertung (1)
- nichtisothermer Mehrphasenfluss (1)
- non-isothermal multiphase flow (1)
- non-monetary valuation (1)
- normal bundle (1)
- numerical cognition (1)
- numerical simulation (1)
- numerical techniques (1)
- numerische Kognition (1)
- numerische Methoden (1)
- numerische Simulation (1)
- nutrition (1)
- obesity (1)
- object based image analysis (1)
- object topicalization (1)
- objektbasierte Bildanalyse (1)
- offspring (1)
- one-sided communication (1)
- ontologies (1)
- open circuit voltage (1)
- optically induced dynamics (1)
- optisch induzierte Dynamik (1)
- optogenetics (1)
- organic carbon (1)
- organic matter quality (1)
- organic solar cells (1)
- organische Solarzellen (1)
- organischer Kohlenstoff (1)
- organisches Material (1)
- organization theory (1)
- organizational reform (1)
- oxidase (1)
- oxocarbon (1)
- parabrachial nucleus (1)
- parallel programming (1)
- parallele Programmierung (1)
- participatory mapping (1)
- particle verbs (1)
- pathway engineering (1)
- peptide (1)
- performance information use (1)
- performance management (1)
- periphyton (1)
- permafrost (1)
- persönliche Informationen (1)
- pharmacodynamics (1)
- photocatalysis (1)
- photochemistry (1)
- photogrammetry (1)
- photoswitches (1)
- photosynthesis (1)
- physical attractiveness (1)
- physiologie-basierte Pharmacokinetic (PBPK) (1)
- physische Attraktivität (1)
- plant-habitat interactions (1)
- plasmon nano-particles (1)
- plasmonic catalysis (1)
- plasmonics (1)
- plasmonische Katalyse (1)
- plasmonische Nanopartikeln (1)
- plastid transformation (1)
- plate boundary friction (1)
- plate motions (1)
- plume-ridge interaction (1)
- plötzliche stratosphärische Erwärmungsereignisse (1)
- political economics (1)
- politische Ökonomie (1)
- polycondensation (1)
- polyesters (1)
- polymer chemistry (1)
- polymer synthesis (1)
- polymers (1)
- polymictic lakes (1)
- polymiktische Seen (1)
- polypeptoids (1)
- popPBPK (1)
- popPK (1)
- population analysis (1)
- population ecology (1)
- porous materials (1)
- poröse Materialien (1)
- precipitation (1)
- predictive modelling (1)
- primed picture naming (1)
- privacy (1)
- process identification (1)
- process synchronization (1)
- prosodic boundary cues (1)
- prosodic phrase boundaries (1)
- prosodische Grenzmarkierungen (1)
- prosodische Phrasengrenzen (1)
- protease inhibitor (1)
- protein kinetics (1)
- protein-polymer conjugate (1)
- protein-protein interaction (1)
- psycholinguistics (1)
- public economics (1)
- public management (1)
- public organizations (1)
- public sector innovation (1)
- pump-probe experiment (1)
- quantum chemistry (1)
- radical reactions (1)
- radiocarbon (1)
- railway infrastructure (1)
- rare-earth metals (1)
- raum-zeitlich (1)
- reactive flux rate constants (1)
- reactive oxygen species (1)
- recommendation (1)
- red giant stars (1)
- red meat (1)
- regional economics (1)
- regularity (1)
- reptiles (1)
- resistance training (1)
- ribosomal dynamics (1)
- ribosome assembly (1)
- riesen unilamellare Vesikel (1)
- rote Riesensterne (1)
- rotes Fleisch (1)
- roughness (1)
- satellite images (1)
- schaltbare Materialien (1)
- scientific workflows (1)
- scrambling (1)
- sediment source fingerprinting (1)
- sediment transport modelling (1)
- seismic cycle modeling (1)
- seismicity and tectonics (1)
- self-paced reading (1)
- seltene Erden (1)
- semantic domain modeling (1)
- semantische Domänenmodellierung (1)
- service composition (1)
- service-oriented architecture (SOA) (1)
- shale strength (1)
- silver nanoparticles (1)
- skeletal muscle (1)
- smart materials (1)
- snow avalanches (1)
- software-based cache coherence (1)
- solution process (1)
- solvent effect (1)
- spatial econometrics (1)
- spatio-temporal (1)
- species distribution (1)
- spectral analysis (1)
- spectroscopy (1)
- speech perception (1)
- spine (1)
- squaric acid (1)
- standard (1)
- start-up subsidy (1)
- stellar evolution (1)
- stellar population (1)
- stellar winds (1)
- stellare Population (1)
- stochastic interacting particles (1)
- stochastisches interagierendes System (1)
- stopped-flow (1)
- stress (1)
- stress changes (1)
- structural properties (1)
- strukturelle Eigenschaften (1)
- subduction (1)
- sudden stratospheric warming (1)
- sulfadiazine (1)
- supramolecular chemistry (1)
- supramolekulare Chemie (1)
- surface hopping dynamics (1)
- surface modification (1)
- surface urban heat island effect (1)
- surface water-groundwater interaction (1)
- suspended sediments (1)
- sustainability (1)
- sustainable urban development (1)
- syntax (1)
- synthetic aperture radar interferometry (1)
- synthetic biology (1)
- synthetische Beobachtungen (1)
- synthetische Biologie (1)
- systematischer Review (1)
- systems biology (1)
- task demands (1)
- taste processing (1)
- teleconnections (1)
- temperature (1)
- the Cauchy problem (1)
- the Goursat problem (1)
- the characteristic Cauchy problem (1)
- the linearised Einstein equation (1)
- theory of mind (1)
- thermal isomerization of azobenzene (1)
- thermisch angeregte Isomerisierung von Azobenzolen (1)
- thermo-mechanical modeling (1)
- thermo-mechanische Modellierung (1)
- thermoregulatory behaviour (1)
- time scale (1)
- time series analysis (1)
- time series investigation (1)
- time-kill curves (1)
- time-series analysis (1)
- tissue engineering (1)
- tobacco (1)
- tobramycin (1)
- transcription factor (1)
- transition path sampling (1)
- translation (1)
- translation theory (1)
- transmembrane protein (1)
- treatment effects (1)
- trend analyses (1)
- trilingualism (1)
- trunk kinematics (1)
- trunk muscle strength (1)
- type 2 diabetes (1)
- ultra-thin membrane (1)
- ultradünne Membranen (1)
- ultrafast phenomena (1)
- ultraschnelle Phänomene (1)
- unconventional shale (1)
- underground coal gasification (1)
- unemployment (1)
- unemployment insurance (1)
- ungulates (1)
- unique column combination (1)
- unkonventionelle Schiefer (1)
- untere kritische Entmischungstemperatur (1)
- upper mantle density heterogeneities (1)
- upper mantle viscosity structure (1)
- urban efficiency (1)
- urban form (1)
- urban heat island effect (1)
- variability (1)
- vertical coupling (1)
- vertikale Kuppelung (1)
- vertrackte Probleme (1)
- water balance (1)
- water reservoir (1)
- wave equation (1)
- wave scattering and diffraction (1)
- wavelet (1)
- weather pattern (1)
- weißer Kohlenstoff (1)
- white carbon (1)
- whole-grain (1)
- wicked problems (1)
- x-ray magnetic circular dichroism (XMCD) (1)
- x-ray magnetic resonant diffraction (XMRD) (1)
- Ärgerregulation (1)
- Ästuar (1)
- Öffentliche Organisationen (1)
- Übungsanleitung (1)
- äquatorialer Elektrojet (1)
- ökologische Modellierung (1)
- азобензолсодержащие ПАВ (1)
- каталитическая изомеризация азобензолов (1)
- плазмонные наночастицы (1)
- показатель преломления азобензолов (1)
Institute
- Institut für Biochemie und Biologie (48)
- Institut für Geowissenschaften (27)
- Institut für Physik und Astronomie (22)
- Institut für Chemie (20)
- Institut für Ernährungswissenschaft (9)
- Sozialwissenschaften (9)
- Institut für Umweltwissenschaften und Geographie (8)
- Department Linguistik (7)
- Hasso-Plattner-Institut für Digital Engineering GmbH (6)
- Institut für Mathematik (6)
- Wirtschaftswissenschaften (6)
- Department Psychologie (4)
- Extern (4)
- Department Sport- und Gesundheitswissenschaften (3)
- Institut für Informatik und Computational Science (3)
- Hasso-Plattner-Institut für Digital Engineering gGmbH (1)
- Historisches Institut (1)
- Institut für Anglistik und Amerikanistik (1)
- Potsdam Institute for Climate Impact Research (PIK) e. V. (1)
Galaxies are among the most complex systems that can currently be modelled with a computer. A realistic simulation must take into account cosmology and gravitation as well as effects of plasma, nuclear, and particle physics that occur on very different time, length, and energy scales. The Milky Way is the ideal test bench for such simulations, because we can observe millions of its individual stars whose kinematics and chemical composition are records of the evolution of our Galaxy. Thanks to the advent of multi-object spectroscopic surveys, we can systematically study stellar populations in a much larger volume of the Milky Way. While the wealth of new data will certainly revolutionise our picture of the formation and evolution of our Galaxy and galaxies in general, the big-data era of Galactic astronomy also confronts us with new observational, theoretical, and computational challenges.
This thesis aims at finding new observational constraints to test Milky-Way models, primarily based on infra-red spectroscopy from the Apache Point Observatory Galactic Evolution Experiment (APOGEE) and asteroseismic data from the CoRoT mission. We compare our findings with chemical-evolution models and more sophisticated chemodynamical simulations. In particular we use the new powerful technique of combining asteroseismic and spectroscopic observations that allows us to test the time dimension of such models for the first time. With CoRoT and APOGEE (CoRoGEE) we can infer much more precise ages for distant field red-giant stars, opening up a new window for Galactic archaeology.
Another important aspect of this work is the forward-simulation approach that we pursued when interpreting these complex datasets and comparing them to chemodynamical models.
The first part of the thesis contains the first chemodynamical study conducted with the APOGEE survey. Our sample comprises more than 20,000 red-giant stars located within 6 kpc from the Sun, and thus greatly enlarges the Galactic volume covered with high-resolution spectroscopic observations. Because APOGEE is much less affected by interstellar dust extinction, the sample covers the disc regions very close to the Galactic plane that are typically avoided by optical surveys. This allows us to investigate the chemo-kinematic properties of the Milky Way's thin disc outside the solar vicinity. We measure, for the first time with high-resolution data, the radial metallicity gradient of the disc as a function of distance from the Galactic plane, demonstrating that the gradient flattens and even changes its sign for mid-plane distances greater than 1 kpc.
Furthermore, we detect a gap between the high- and low-[$\alpha$/Fe] sequences in the chemical-abundance diagram (associated with the thin and thick disc) that unlike in previous surveys can hardly be explained by selection effects. Using 6D kinematic information, we also present chemical-abundance diagrams cleaned from stars on kinematically hot orbits. The data allow us to confirm without doubt that the scale length of the (chemically-defined) thick disc is significantly shorter than that of the thin disc.
In the second part, we present our results of the first combination of asteroseismic and spectroscopic data in the context of Galactic Archaeology. We analyse APOGEE follow-up observations of 606 solar-like oscillating red giants in two CoRoT fields close to the Galactic plane. These stars cover a large radial range of the Galactic disc (4.5 kpc $\lesssim R_{\rm Gal}\lesssim15$ kpc) and a large age baseline (0.5 Gyr $\lesssim \tau\lesssim$ 13 Gyr), allowing us to study the age- and radius-dependence of the [$\alpha$/Fe] vs. [Fe/H] distributions. We find that the age distribution of the high-[$\alpha$/Fe] sequence appears to be broader than expected from a monolithically-formed old thick disc that stopped to form stars 10 Gyr ago. In particular, we discover a significant population of apparently young, [$\alpha$/Fe]-rich stars in the CoRoGEE data whose existence cannot be explained by standard chemical-evolution models. These peculiar stars are much more abundant in the inner CoRoT field LRc01 than in the outer-disc field LRc01, suggesting that at least part of this population has a chemical-evolution rather than a stellar-evolution origin, possibly due to a peculiar chemical-enrichment history of the inner disc. We also find that strong radial migration is needed to explain the abundance of super-metal-rich stars in the outer disc.
Finally, we use the CoRoGEE sample to study the time evolution of the radial metallicity gradient in the thin disc, an observable that has been the subject of observational and theoretical debate for more than 20 years. By dividing the CoRoGEE dataset into six age bins, performing a careful statistical analysis of the radial [Fe/H], [O/H], and [Mg/Fe] distributions, and accounting for the biases introduced by the observation strategy, we obtain reliable gradient measurements. The slope of the radial [Fe/H] gradient of the young red-giant population ($-0.058\pm0.008$ [stat.] $\pm0.003$ [syst.] dex/kpc) is consistent with recent Cepheid data. For the age range of $1-4$ Gyr, the gradient steepens slightly ($-0.066\pm0.007\pm0.002$ dex/kpc), before flattening again to reach a value of $\sim-0.03$ dex/kpc for stars with ages between 6 and 10 Gyr. This age dependence of the [Fe/H] gradient can be explained by a nearly constant negative [Fe/H] gradient of $\sim-0.07$ dex/kpc in the interstellar medium over the past 10 Gyr, together with stellar heating and migration. Radial migration also offers a new explanation for the puzzling observation that intermediate-age open clusters in the solar vicinity (unlike field stars) tend to have higher metallicities than their younger counterparts. We suggest that non-migrating clusters are more likely to be kinematically disrupted, which creates a bias towards high-metallicity migrators from the inner disc and may even steepen the intermediate-age cluster abundance gradient.
The work done during the PhD studies has been focused on measurements of distribution functions of rotating galaxies using integral field spectroscopy observations.
Throughout the main body of research presented here we have been using CALIFA (Calar Alto Legacy Integral Field Area) survey stellar velocity fields to obtain robust measurements of circular velocities for rotating galaxies of all morphological types. A crucial part of the work was enabled by well-defined CALIFA sample selection criteria: it enabled reconstructing sample-independent distributions of galaxy properties.
In Chapter 2, we measure the distribution in absolute magnitude - circular velocity space for a well-defined sample of 199 rotating CALIFA galaxies using their stellar kinematics. Our aim in this analysis is to avoid subjective selection criteria and to take volume and large-scale structure factors into account. Using stellar velocity fields instead of gas emission line kinematics allows including rapidly rotating early type galaxies. Our initial sample contains 277 galaxies with available stellar velocity fields and growth curve r-band photometry. After rejecting 51 velocity fields that could not be modelled due to the low number of bins, foreground contamination or significant interaction we perform Markov Chain Monte Carlo (MCMC) modelling of the velocity fields, obtaining the rotation curve and kinematic parameters and their realistic uncertainties. We perform an extinction correction and calculate the circular velocity v_circ accounting for pressure support a given galaxy has. The resulting galaxy distribution on the M_r - v_circ plane is then modelled as a mixture of two distinct populations, allowing robust and reproducible rejection of outliers, a significant fraction of which are slow rotators. The selection effects are understood well enough that the incompleteness of the sample can be corrected and the 199 galaxies can be weighted by volume and large-scale structure factors enabling us to fit a volume-corrected Tully-Fisher relation (TFR). More importantly, we also provide the volume-corrected distribution of galaxies in the M_r - v_circ plane, which can be compared with cosmological simulations. The joint distribution of the luminosity and circular velocity space densities, representative over the range of -20 > M_r > -22 mag, can place more stringent constraints on the galaxy formation and evolution scenarios than linear TFR fit parameters or the luminosity function alone.
In Chapter 3, we measure one of the marginal distributions of the M_r - v_circ distribution: the circular velocity function of rotating galaxies. The velocity function is a fundamental observable statistic of the galaxy population, being of a similar importance as the luminosity function, but much more difficult to measure. We present the first directly measured circular velocity function that is representative between 60 < v_circ < 320 km s^-1 for galaxies of all morphological types at a given rotation velocity. For the low mass galaxy population 60 < v_circ < 170 km s^-1, we use the HIPASS velocity function. For the massive galaxy population 170 < v_circ < 320 km s^-1, we use stellar circular velocities from CALIFA. The CALIFA velocity function includes homogeneous velocity measurements of both late and early-type rotation-supported galaxies. It has the crucial advantage of not missing gas-poor massive ellipticals that HI surveys are blind to. We show that both velocity functions can be combined in a seamless manner, as their ranges of validity overlap. The resulting observed velocity function is compared to velocity functions derived from cosmological simulations of the z = 0 galaxy population. We find that dark matter-only simulations show a strong mismatch with the observed VF. Hydrodynamic Illustris simulations fare better, but still do not fully reproduce observations.
In Chapter 4, we present some other work done during the PhD studies, namely, a method that improves the precision of specific angular measurements by combining simultaneous Markov Chain Monte Carlo modelling of ionised gas 2D velocity fields and HI linewidths. To test the method we use a sample of 25 galaxies from the Sydney-AAO Multi-object Integral field (SAMI) survey that had matching ALFALFA HI linewidths. Such a method allows constraining the rotation curve both in the inner regions of a galaxy and in its outskirts, leading to increased precision of specific angular momentum measurements. It could be used to further constrain the observed relation between galaxy mass, specific angular momentum and morphology (Obreschkow & Glazebrook 2014).
Mathematical and computational methods are presented in the appendices.
In this era of high-speed informatization and globalization, online education is no longer an exquisite concept in the ivory tower, but a rapidly developing industry closely relevant to people's daily lives. Numerous lectures are recorded in form of multimedia data, uploaded to the Internet and made publicly accessible from anywhere in this world. These lectures are generally addressed as e-lectures. In recent year, a new popular form of e-lectures, the Massive Open Online Courses (MOOCs), boosts the growth of online education industry and somehow turns "learning online" into a fashion.
As an e-learning provider, besides to keep improving the quality of e-lecture content, to provide better learning environment for online learners is also a highly important task. This task can be preceded in various ways, and one of them is to enhance and upgrade the learning materials provided: e-lectures could be more than videos. Moreover, this process of enhancement or upgrading should be done automatically, without giving extra burdens to the lecturers or teaching teams, and this is the aim of this thesis.
The first part of this thesis is an integrated framework of multi-lingual subtitles production, which can help online learners penetrate the language barrier. The framework consists of Automatic Speech Recognition (ASR), Sentence Boundary Detection (SBD) and Machine Translation (MT), among which the proposed SBD solution is major technical contribution, building on Deep Neural Network (DNN) and Word Vector (WV) and achieving state-of-the-art performance. Besides, a quantitative evaluation with dozens of volunteers is also introduced to measure how these auto-generated subtitles could actually help in context of e-lectures.
Secondly, a technical solution "TOG" (Tree-Structure Outline Generation) is proposed to extract textual content from the displaying slides recorded in video and re-organize them into a hierarchical lecture outline, which may serve in multiple functions, such like preview, navigation and retrieval. TOG runs adaptively and can be roughly divided into intra-slide and inter-slides phases. Table detection and lecture video segmentation can be implemented as sub- or post-application in these two phases respectively. Evaluation on diverse e-lectures shows that all the outlines, tables and segments achieved are trustworthily accurate.
Based on the subtitles and outlines previously created, lecture videos can be further split into sentence units and slide-based segment units. A lecture highlighting process is further applied on these units, in order to capture and mark the most important parts within the corresponding lecture, just as what people do with a pen when reading paper books. Sentence-level highlighting depends on the acoustic analysis on the audio track, while segment-level highlighting focuses on exploring clues from the statistical information of related transcripts and slide content. Both objective and subjective evaluations prove that the proposed lecture highlighting solution is with decent precision and welcomed by users.
All above enhanced e-lecture materials have been already implemented in actual use or made available for implementation by convenient interfaces.
This is a cumulative dissertation comprising three original studies (one published, one in revision, one submitted; Effective December 2017) investigating how reptile species in arid Australia respond to various climatic parameters at different spatial scales and analysing the two potential main underlying mechanisms: thermoregulatory behaviour and species interactions. This dissertation combines extensive individual-based field data across trophic levels, selected field experiments, statistical analyses, and predictive modelling techniques. Mechanisms and processes detected in this dissertation can now be used to predict potential future changes in the community of arid-zone lizards. This knowledge will help improving our fundamental understanding of the consequences of global change and thereby prevent biodiversity loss in a vulnerable ecosystem.
In the arable soil landscape of hummocky ground moraines, an erosion-affected spatial differentiation of soils can be observed. Man-made erosion leads to soil profile modifications along slopes with changed solum thickness and modified properties of soil horizons due to water erosion in combination with tillage operations. Soil erosion creates, thereby, spatial patterns of soil properties (e.g., texture and organic matter content) and differences in crop development. However, little is known about the manner in which water fluxes are affected by soil-crop interactions depending on contrasting properties of differently-developed soil horizons and how water fluxes influence the carbon transport in an eroded landscape. To identify such feedbacks between erosion-induced soil profile modifications and the 1D-water and solute balance, high-precision weighing lysimeters equipped with a wide range of sensor technique were filled with undisturbed soil monoliths that differed in the degree of past soil erosion. Furthermore, lysimeter effluent concentrations were analyzed for dissolved carbon fractions in bi-weekly intervals.
The water balance components measured by high precision lysimeters varied from the most eroded to the less eroded monolith up to 83 % (deep drainage) primarily caused due to varying amounts of precipitation and evapotranspiration for a 3-years period. Here, interactions between crop development and contrasting rainfall interception by above ground biomass could explain differences in water balance components. Concentrations of dissolved carbon in soil water samples were relatively constant in time, suggesting carbon leaching was mainly affected by water fluxes in this observation period. For the lysimeter-based water balance analysis, a filtering scheme was developed considering temporal autocorrelation. The minute-based autocorrelation analysis of mass changes from lysimeter time series revealed characteristic autocorrelation lengths ranging from 23 to 76 minutes. Thereby, temporal autocorrelation provided an optimal approximation of precipitation quantities. However, the high temporal resolution in lysimeter time series is restricted by the lengths of autocorrelation.
Erosion-induced but also gradual changes in soil properties were reflected by dynamics of soil water retention properties in the lysimeter soils. Short-term and long-term hysteretic water retention data suggested seasonal wettability problems of soils increasingly limited rewetting of previously dried pore regions. Differences in water retention were assigned to soil tillage operations and the erosion history at different slope positions. The threedimensional spatial pattern of soil types that result from erosional soil profile modifications were also reflected in differences of crop root development at different landscape positions. Contrasting root densities revealed positive relations of root and aboveground plant characteristics. Differences in the spatially-distributed root growth between different eroded soil types provided indications that root development was affected by the erosion-induced soil evolution processes.
Overall, the current thesis corroborated the hypothesis that erosion-induced soil profile modifications affect the soil water balance, carbon leaching and soil hydraulic properties, but also the crop root system is influenced by erosion-induced spatial patterns of soil properties in the arable hummocky post glacial soil landscape. The results will help to improve model predictions of water and solute movement in arable soils and to understand interactions between soil erosion and carbon pathways regarding sink-or-source terms in landscapes.
Natural products and their derivatives have always been a source of drug leads. In particular, bacterial compounds have played an important role in drug development, for example in the field of antibiotics. A decrease in the discovery of novel leads from natural sources and the hope of finding new leads through the generation of large libraries of drug-like compounds by combinatorial chemistry aimed at specific molecular targets drove the pharmaceutical companies away from research on natural products. However, recent technological advances in genetics, bioinformatics and analytical chemistry have revived the interest in natural products. The ribosomally synthesized and post-translationally modified peptides (RiPPs) are a group of natural products generated by the action of post-translationally modifying enzymes on precursor peptides translated from mRNA by ribosomes. The great substrate promiscuity exhibited by many of the enzymes from RiPP biosynthetic pathways have led to the generation of hundreds of novel synthetic and semisynthetic variants, including variants carrying non-canonical amino acids (ncAAs). The microviridins are a family of RiPPs characterized by their atypical tricyclic structure composed of lactone and lactam rings, and their activity as serine protease inhibitors. The generalities of their biosynthetic pathway have already been described, however, the lack of information on details such as the protease responsible for cleaving off the leader peptide from the cyclic core peptide has impeded the fast and cheap production of novel microviridin variants. In the present work, knowledge on leader peptide activation of enzymes from other RiPP families has been extrapolated to the microviridin family, making it possible to bypass the need of a leader peptide. This feature allowed for the exploitation of the microviridin biosynthetic machinery for the production of novel variants through the establishment of an efficient one-pot in vitro platform. The relevance of this chemoenzymatic approach has been exemplified by the synthesis of novel potent serine protease inhibitors from both rationally-designed peptide libraries and bioinformatically predicted microviridins. Additionally, new structure-activity relationships (SARs) could be inferred by screening microviridin intermediates. The significance of this technique was further demonstrated by the simple incorporation of ncAAs into the microviridin scaffold.
Persistently high unemployment rates are a major threat to the social cohesion in many societies. To moderate the consequences of unemployment industrialized countries spend substantial shares of their GDP on labor market policies, while in recent years there has been a shift from passive measures, such as transfer payments, towards more activating elements which aim to promote the reintegration into the labor market. Although, there exists a wide range of evidence about the effects of traditional active labor market policies (ALMP) on participants’ subsequent labor market outcomes, a deeper understanding of the impact of these programs on the job search behavior and the interplay with long-term labor market outcomes is necessary. This allows policy makers to improve the design of labor market policies and the allocation of unemployed workers into specific programs. Moreover, previous studies have shown that many traditional ALMP programs, like public employment or training schemes, do not achieve the desired results. This underlines the importance of understanding the effect mechanisms, but also the need to develop innovative programs that are more effective. This thesis extends the existing literature with respect to several dimensions.
First, it analyzes the impact of job seekers’ beliefs about upcoming ALMPs programs on the effectiveness of realized treatments later during the unemployment spell. This provides important insights with respect to the job search process and relates potential anticipation effects (on the job seekers behavior before entering a program) to the vast literature evaluating the impact of participating in an ALMP program on subsequent outcomes. The empirical results show that training programs are more effective if the participants expect participation ex ante, while expected treatment effects are unrelated to the actual labor market outcomes of participants. A subsequent analysis of the effect mechanisms shows that job seekers who expect to participate also receive more information by their caseworker and show a higher willingness to adjust their search behavior in association with an upcoming ALMP program. The findings suggest that the effectiveness of training programs can be improved by providing more detailed information about the possibility of a future treatment early during the unemployment spell.
Second, the thesis investigates the effects of a relatively new class of programs that aim to improve the geographical mobility of unemployed workers with respect to the job search behavior, the subsequent job finding prospects and the returns to labor market mobility. To estimate the causal impact of these programs, it is exploited that local employment agencies have a degree of autonomy when deciding about the regional-specific policy mix. The findings show that the policy style of the employment agency indeed affects the job search behavior of unemployed workers. Job seekers who are assigned to agencies with higher preferences for mobility programs increase their search radius without affecting the total number of job applications. This shift of the search effort to distant regions leads to a higher probability to find a regular job and higher wages. Moreover, it is shown that participants in one of the subsidy programs who move to geographically distant region a earn significantly higher wages, end up in more stable jobs and face a higher long-run employment probability compared to non-participants.
Third, the thesis offers an empirical assessment of the unconfoundedness assumption with respect to the relevance of variables that are usually unobserved in studies evaluating ALMP programs. A unique dataset that combines administrative records and survey data allows us to observe detailed information on typical covariates, as well as usually unobserved variables including personality traits, attitudes, expectations, intergenerational information, as well as indicators about social networks and labor market flexibility. The findings show that, although our set of usually unobserved variables indeed has a significant effect on the selection into ALMP programs, the overall impact when estimating treatment effects is rather small.
Finally, the thesis also examines the importance of gender differences in reservation wages that allows assessing the importance of special ALMP programs targeting women. In particular, when including reservation wages in a wage decomposition exercise, the gender gap in realized wages becomes small and statistically insignificant. The strong connection between gender differences in reservation wages and realized wages raises the question how these differences in reservation wages are set in the first place. Since traditional covariates cannot sufficiently explain the gender gap in reservation wages, we perform subgroup analysis to better understand what the driving forces behind this gender gap are.
Bisherige Studien zur Demokratieförderung analysierten „erfolgreiche“ Beispiele. Das ist teilweise eine Reflektion der politischen Ökonomie von Demokratieförderung, in der sie Beispielen im Inland erzeugter demokratischer Durchbrüche folgt. Dennoch kann eine wissenschaftliche Analyse externer Einflüsse auf interne Veränderungen sich nicht nur auf Fälle erfolgreicher Demokratieentwicklung beziehen, sondern muss Beispiele von Regimeveränderungen, die nicht in einer Demokratie resultierten, berücksichtigen, um Selektionsvorurteile zu vermeiden und die kausalen Mechanismen zu isolieren, die für einen demokratischen Wandel notwendig sind, neben dem Zusammenbruch eines autoritären Regimes und einer Liberalisierung.
In dieser Studie dienen Marokko und Tunesien als Fallbeispiele, Länder, die nach langjähriger Diktaturerfahrung versuchen demokratische Strukturen aufzubauen und sich anderen Herausforderungen stellen müssen als sich demokratisierende Regime, die über einen relativ effektiven Staat verfügen.
Da es wenig Austausch zwischen Analysten von demokratischen Übergängen, Konsolidierung und Post-Konflikt Staatenbildung gab, überrascht, dass diese radikal unterschiedliche Situation von demokratischem Wandel und variierenden Rollen externer Akteure in jeder Kategorie bisher nicht differenziert wurde. Die Studie widmet sich den hieraus resultierenden Kernfragen: „Wie, Warum und durch Was wird Demokratieförderung durch externe Akteure funktionieren?“
Die Frage nach dem „Wie“ ist hier die schwierigste, es ist eine Frage nach den Methoden und Strategien des Demokratisierungsprozesses sowie der Unterstützung, die sorgfältig durchdachte Techniken und ihre breite Akzeptanz durch eine Vielzahl von Partner erfordert. Antwort auf die Frage nach dem „Was“ und „Warum“ hingegen findet sich in der Grundlage schlechter Regierungsarbeit und schlechter Wirtschaftsleistung, die zu Aufständen der Bevölkerung führen. Die Resultate der Studie tragen zum Fortschritt in der Demokratieförderung bei.
Exploring the Arabidopsis metabolic landscape by genetic mapping integrated with network analysis
(2017)
Background and objectives: Age-related losses of lower extremity muscle strength/power and deficits in static and particularly dynamic balance are associated with impaired functional performance and the occurrence of falls. It has been shown that balance and resistance training have the potential to improve balance and muscle strength in healthy older adults. However, it is still open to debate how the effectiveness of balance and resistance training in older adults is influenced by different factors. This includes the role of trunk muscle strength, the comprehensive effects of combined balance and resistance training, and the role of exercise supervision. Therefore, the primary objectives of this doctoral thesis are to investigate the relationship between trunk muscle strength and balance performance and to examine the effects of an expert-based balance and resistance training protocol on various measures of balance and lower extremity muscle strength/power in older adults. Furthermore, the impact of supervised versus unsupervised balance and/or resistance training interventions in the elderly will be evaluated.
Methods: Healthy older adults aged 63-80 years were included in a cross-sectional study, a longitudinal study, and a meta-analysis (range group means meta-analysis: 65.3-81.1 years) registering balance and muscle strength/power performance. Different measures of balance (i.e., static/dynamic, proactive, reactive) were examined using clinical (e.g., Romberg test) and instrumented tests (e.g., 10 meter walking test on a sensor-equipped walkway). Isometric strength of the trunk muscles was assessed using instrumented trunk muscle strength apparatus and lower extremity dynamic muscle strength/power was examined using clinical tests (e.g., Chair Stand Test). Further, a combined balance and resistance training protocol was applied to examine training-induced effects on balance and muscle strength/power as well as the role of supervision in older adults.
Results: Findings revealed that measures of trunk muscle strength and static steady-state balance as well as specific measures of dynamic steady-state balance were significantly associated in the elderly (0.42 ≤ r ≤ 0.57). Combined balance and resistance training significantly improved older adults' static/dynamic steady-state (e.g., Romberg test; habitual gait speed), pro-active (e.g., Timed Up and Go Test), and reactive balance (e.g., Push and Release Test) as well as muscle strength/power (e.g., Chair Stand Test) (0.62 ≤ Cohen’s d ≤ 2.86; all p < 0.05). Supervised compared to unsupervised balance and/or resistance training was superior in enhancing older adults' balance and muscle strength/power performance regarding all observed outcome categories [longitudinal study: effects for the supervised group 0.26 ≤ d ≤ 2.86, effects for the unsupervised group 0.06 ≤ d ≤ 2.30; meta-analysis: all between-subject standardized mean differences (SMDbs) in favor of the supervised training programs 0.24-0.53]. The meta-analysis additionally showed larger effects in favor of supervised interventions when compared to completely unsupervised interventions (0.28 ≤ SMDbs ≤ 1.24). These effects in favor of the supervised programs faded when compared with studies that implemented a small amount of supervised sessions in their unsupervised interventions (−0.06 ≤ SMDbs ≤ 0.41).
Conclusions: Trunk muscle strength is associated with steady-state balance performance and may therefore be integrated in fall-preventive exercise interventions for older adults. The examined positive effects on a large number of important intrinsic fall risk factors (e.g., balance deficits, muscle weakness) imply that particularly the combination of balance and resistance training appears to be a feasible and effective exercise intervention for fall prevention. Owing to the beneficial effects of supervised compared to unsupervised interventions, supervised sessions should be integrated in fall-preventive balance and/or resistance training programs for older adults.
Steep mountain channels are an important component of the fluvial system. On geological timescales, they shape mountain belts and counteract tectonic uplift by erosion. Their channels are strongly coupled to hillslopes and they are often the main source of sediment transported downstream to low-gradient rivers and to alluvial fans, where commonly settlements in mountainous areas are located. Hence, mountain streams are the cause for one of the main natural hazards in these regions. Due to climate change and a pronounced populating of mountainous regions the attention given to this threat is even growing. Although quantitative studies on sediment transport have significantly advanced our knowledge on measuring and calibration techniques we still lack studies of the processes within mountain catchments. Studies examining the mechanisms of energy and mass exchange on small temporal and spatial scales in steep streams remain sparse in comparison to low-gradient alluvial channels.
In the beginning of this doctoral project, a vast amount of experience and knowledge of a steep stream in the Swiss Prealps had to be consolidated in order to shape the principal aim of this research effort. It became obvious, that observations from within the catchment are underrepresented in comparison to experiments performed at the catchment’s outlet measuring fluxes and the effects of the transported material. To counteract this imbalance, an examination of mass fluxes within the catchment on the process scale was intended. Hence, this thesis is heavily based on direct field observations, which are generally rare in these environments in quantity and quality. The first objective was to investigate the coupling of the channel with surrounding hillslopes, the major sources of sediment. This research, which involved the monitoring of the channel and adjacent hillslopes, revealed that alluvial channel steps play a key role in coupling of channel and hillslopes. The observations showed that hillslope stability is strongly associated with the step presence and an understanding of step morphology and stability is therefore crucial in understanding sediment mobilization. This finding refined the way we think about the sediment dynamics in steep channels and motivated continued research of the step dynamics. However, soon it became obvious that the technological basis for developing field tests and analyzing the high resolution geometry measured in the field was not available. Moreover, for many geometrical quantities in mountain channels definitions and a clear scientific standard was not available. For example, these streams are characterized by a high spatial variability of the channel banks, preventing straightforward calculations of the channel width without a defined reference. Thus, the second and inevitable part of this thesis became the development and evaluation of scientific tools in order to investigate the geometrical content of the study reach thoroughly. The developed framework allowed the derivation of various metrics of step and channel geometry which facilitated research on the a large data set of observations of channel steps. In the third part, innovative, physically-based metrics have been developed and compared to current knowledge on step formation, suggested in the literature. With this analyses it could be demonstrated that the formation of channel steps follow a wide range of hydraulic controls. Due to the wide range of tested parameters channel steps observed in a natural stream were attributed to different mechanisms of step formation, including those based on jamming and those based on key-stones. This study extended our knowledge on step formation in a steep stream and harmonized different, often time seen as competing, processes of step formation. This study was based on observations collected at one point in time. In the fourth part of this project, the findings of the snap-shot observations were extended in the temporal dimension and the derived concepts have been utilized to investigate reach-scale step patterns in response to large, exceptional flood events. The preliminary results of this work based on the long-term analyses of 7 years of long profile surveys showed that the previously observed channel-hillslope mechanism is the responsible for the short-term response of step formation.
The findings of the long-term analyses of step patterns drew a bow to the initial observations of a channel-hillslope system which allowed to join the dots in the dynamics of steep stream. Thus, in this thesis a broad approach has been chosen to gain insights into the complex system of steep mountain rivers. The effort includes in situ field observations (article I), the development of quantitative scientific tools (article II), the reach-scale analyses of step-pool morphology (article III) and its temporal evolution (article IV). With this work our view on the processes within the catchment has been advanced towards a better mechanistic understanding of these fluvial system relevant to improve applied scientific work.
Modern welfare states aim at designing unemployment insurance (UI) schemes which minimize the length of unemployment spells. A variety of institutions and incentives, which are embedded in UI schemes across OECD countries, reflect this attempt. For instance, job seekers entering UI are often provided with personal support through a caseworker. They also face the requirement to regularly submit a minimum number of job applications, which is typically enforced through benefit cuts in the case of non-compliance. Moreover, job seekers may systematically receive information on their re-employment prospects. As a consequence, UI design has become a complex task. Policy makers need to define not only the amount and duration of benefit payments, but also several other choice parameters. These include the intensity and quality of personal support through caseworkers, the level of job search requirements, the strictness of enforcement, and the information provided to unemployed individuals. Causal estimates on how these parameters affect re-employment outcomes are thus central inputs to the design of modern UI systems: how much do individual caseworkers influence the transition out of unemployment? Does the requirement of an additional job application translate into increased job finding? Do individuals behave differently when facing a strict versus mild enforcement system? And how does information on re-employment prospects influence the job search decision? This dissertation proposes four novel research designs to answer this question. Chapters one to three elaborate quasi-experimental identification strategies, which are applied to large-scale administrative data from Switzerland. They, respectively, measure how personal interactions with caseworkers (chapter one), the level of job search requirements (chapter two) and the strictness of enforcement (chapter three) affect re-employment outcomes. Chapter four proposes a structural estimation approach, based on linked survey and administrative data from Germany. It studies how over-optimism on future wage offers affects the decision to search for work, and how the provision of information changes this decision.
With recent advances in the area of information extraction, automatically extracting structured information from a vast amount of unstructured textual data becomes an important task, which is infeasible for humans to capture all information manually. Named entities (e.g., persons, organizations, and locations), which are crucial components in texts, are usually the subjects of structured information from textual documents. Therefore, the task of named entity mining receives much attention. It consists of three major subtasks, which are named entity recognition, named entity linking, and relation extraction.
These three tasks build up an entire pipeline of a named entity mining system, where each of them has its challenges and can be employed for further applications. As a fundamental task in the natural language processing domain, studies on named entity recognition have a long history, and many existing approaches produce reliable results. The task is aiming to extract mentions of named entities in text and identify their types. Named entity linking recently received much attention with the development of knowledge bases that contain rich information about entities. The goal is to disambiguate mentions of named entities and to link them to the corresponding entries in a knowledge base. Relation extraction, as the final step of named entity mining, is a highly challenging task, which is to extract semantic relations between named entities, e.g., the ownership relation between two companies.
In this thesis, we review the state-of-the-art of named entity mining domain in detail, including valuable features, techniques, evaluation methodologies, and so on. Furthermore, we present two of our approaches that focus on the named entity linking and relation extraction tasks separately.
To solve the named entity linking task, we propose the entity linking technique, BEL, which operates on a textual range of relevant terms and aggregates decisions from an ensemble of simple classifiers. Each of the classifiers operates on a randomly sampled subset of the above range. In extensive experiments on hand-labeled and benchmark datasets, our approach outperformed state-of-the-art entity linking techniques, both in terms of quality and efficiency.
For the task of relation extraction, we focus on extracting a specific group of difficult relation types, business relations between companies. These relations can be used to gain valuable insight into the interactions between companies and perform complex analytics, such as predicting risk or valuating companies. Our semi-supervised strategy can extract business relations between companies based on only a few user-provided seed company pairs. By doing so, we also provide a solution for the problem of determining the direction of asymmetric relations, such as the ownership_of relation. We improve the reliability of the extraction process by using a holistic pattern identification method, which classifies the generated extraction patterns. Our experiments show that we can accurately and reliably extract new entity pairs occurring in the target relation by using as few as five labeled seed pairs.
Functional nanoporous carbon-based materials derived from oxocarbon-metal coordination complexes
(2017)
Nanoporous carbon based materials are of particular interest for both science and industry due to their exceptional properties such as a large surface area, high pore volume, high electroconductivity as well as high chemical and thermal stability. Benefiting from these advantageous properties, nanoporous carbons proved to be useful in various energy and environment related applications including energy storage and conversion, catalysis, gas sorption and separation technologies. The synthesis of nanoporous carbons classically involves thermal carbonization of the carbon precursors (e.g. phenolic resins, polyacrylonitrile, poly(vinyl alcohol) etc.) followed by an activation step and/or it makes use of classical hard or soft templates to obtain well-defined porous structures. However, these synthesis strategies are complicated and costly; and make use of hazardous chemicals, hindering their application for large-scale production. Furthermore, control over the carbon materials properties is challenging owing to the relatively unpredictable processes at the high carbonization temperatures.
In the present thesis, nanoporous carbon based materials are prepared by the direct heat treatment of crystalline precursor materials with pre-defined properties. This synthesis strategy does not require any additional carbon sources or classical hard- or soft templates. The highly stable and porous crystalline precursors are based on coordination compounds of the squarate and croconate ions with various divalent metal ions including Zn2+, Cu2+, Ni2+, and Co2+, respectively. Here, the structural properties of the crystals can be controlled by the choice of appropriate synthesis conditions such as the crystal aging temperature, the ligand/metal molar ratio, the metal ion, and the organic ligand system. In this context, the coordination of the squarate ions to Zn2+ yields porous 3D cube crystalline particles. The morphology of the cubes can be tuned from densely packed cubes with a smooth surface to cubes with intriguing micrometer-sized openings and voids which evolve on the centers of the low index faces as the crystal aging temperature is raised. By varying the molar ratio, the particle shape can be changed from truncated cubes to perfect cubes with right-angled edges.
These crystalline precursors can be easily transformed into the respective carbon based materials by heat treatment at elevated temperatures in a nitrogen atmosphere followed by a facile washing step. The resulting carbons are obtained in good yields and possess a hierarchical pore structure with well-organized and interconnected micro-, meso- and macropores. Moreover, high surface areas and large pore volumes of up to 1957 m2 g-1 and 2.31 cm3 g-1 are achieved, respectively, whereby the macroscopic structure of the precursors is preserved throughout the whole synthesis procedure.
Owing to these advantageous properties, the resulting carbon based materials represent promising supercapacitor electrode materials for energy storage applications. This is exemplarily demonstrated by employing the 3D hierarchical porous carbon cubes derived from squarate-zinc coordination compounds as electrode material showing a specific capacitance of 133 F g-1 in H2SO4 at a scan rate of 5 mV s-1 and retaining 67% of this specific capacitance when the scan rate is increased to 200 mV s-1.
In a further application, the porous carbon cubes derived from squarate-zinc coordination compounds are used as high surface area support material and decorated with nickel nanoparticles via an incipient wetness impregnation. The resulting composite material combines a high surface area, a hierarchical pore structure with high functionality and well-accessible pores. Moreover, owing to their regular micro-cube shape, they allow for a good packing of a fixed-bed flow reactor along with high column efficiency and a minimized pressure drop throughout the packed reactor. Therefore, the composite is employed as heterogeneous catalyst in the selective hydrogenation of 5-hydroxymethylfurfural to 2,5-dimethylfuran showing good catalytic performance and overcoming the conventional problem of column blocking.
Thinking about the rational design of 3D carbon geometries, the functions and properties of the resulting carbon-based materials can be further expanded by the rational introduction of heteroatoms (e.g. N, B, S, P, etc.) into the carbon structures in order to alter properties such as wettability, surface polarity as well as the electrochemical landscape. In this context, the use of crystalline materials based on oxocarbon-metal ion complexes can open a platform of highly functional materials for all processes that involve surface processes.
The field of nanophotonics focuses on the interaction between electromagnetic radiation and matter on the nanometer scale. The elements of nanoscale photonic devices can transfer excitation energy non-radiatively from an excited donor molecule to an acceptor molecule by Förster resonance energy transfer (FRET). The efficiency of this energy transfer is highly dependent on the donor-acceptor distance. Hence, in these nanoscale photonic devices it is of high importance to have a good control over the spatial assembly of used fluorophores. Based on molecular self-assembly processes, various nanostructures can be produced. Here, DNA nanotechnology and especially the DNA origami technique are auspicious self-assembling methods. By using DNA origami nanostructures different fluorophores can be introduced with a high local control to create a variety of nanoscale photonic objects. The applications of such nanostructures range from photonic wires and logic gates for molecular computing to artificial light harvesting systems for artificial photosynthesis.
In the present cumulative doctoral thesis, different FRET systems on DNA origami structures have been designed and thoroughly analyzed. Firstly, the formation of guanine (G) quadruplex structures from G rich DNA sequences has been studied based on a two-color FRET system (Fluorescein (FAM)/Cyanine3 (Cy3)). Here, the influences of different cations (Na+ and K+), of the DNA origami structure and of the DNA sequence on the G-quadruplex formation have been analyzed. In this study, an ion-selective K+ sensing scheme based on the G-quadruplex formation on DNA origami structures has been developed. Subsequently, the reversibility of the G-quadruplex formation on DNA origami structures has been evaluated. This has been done for the simple two-color FRET system which has then been advanced to a switchable photonic wire by introducing additional fluorophores (FAM/Cy3/Cyanine5 (Cy5)/IRDye®700). In the last part, the emission intensity of the acceptor molecule (Cy5) in a three-color FRET cascade has been tuned by arranging multiple donor (FAM) and transmitter (Cy3) molecules around the central acceptor molecule. In such artificial light harvesting systems, the excitation energy is absorbed by several donor and transmitter molecules followed by an energy transfer to the acceptor leading to a brighter Cy5 emission. Furthermore, the range of possible excitation wavelengths is extended by using several different fluorophores (FAM/Cy3/Cy5). In this part of the thesis, the light harvesting efficiency (antenna effect) and the FRET efficiency of different donor/transmitter/acceptor assemblies have been analyzed and the artificial light harvesting complex has been optimized in this respect.
According to the classical plume hypothesis, mantle plumes are localized upwellings of hot, buoyant material in the Earth’s mantle. They have a typical mushroom shape, consisting of a large plume head, which is associated with the formation of voluminous flood basalts (a Large
Igneous Province) and a narrow plume tail, which generates a linear, age-progressive chain of volcanic edifices (a hotspot track) as the tectonic plate migrates over the relatively stationary plume. Both plume heads and tails reshape large areas of the Earth’s surface over many tens of millions of years.
However, not every plume has left an exemplary record that supports the classical hypothesis. The main objective of this thesis is therefore to study how specific hotspots have created the crustal thickness pattern attributed to their volcanic activities. Using regional geodynamic
models, the main chapters of this thesis address the challenge of deciphering the three individual (and increasingly complex) Réunion, Iceland, and Kerguelen hotspot histories, especially focussing on the interactions between the respective plume and nearby spreading ridges.
For this purpose, the mantle convection code ASPECT is used to set up three-dimensional numerical models, which consider the specific local surroundings of each plume by prescribing time-dependent boundary conditions for temperature and mantle flow. Combining reconstructed plate boundaries and plate motions, large-scale global flow velocities and an inhomogeneous lithosphere thickness distribution together with a dehydration rheology represents a novel setup for regional convection models.
The model results show the crustal thickness pattern produced by the plume, which is compared to present-day topographic structures, crustal thickness estimates and age determinations of volcanic provinces associated with hotspot activity. Altogether, the model results agree well
with surface observations. Moreover, the dynamic development of the plumes in the models provide explanations for the generation of smaller, yet characteristic volcanic features that were previously unexplained. Considering the present-day state of a model as a prediction for the
current temperature distribution in the mantle, it cannot only be compared to observations on the surface, but also to structures in the Earth’s interior as imaged by seismic tomography.
More precisely, in the case of the Réunion hotspot, the model demonstrates how the distinctive gap between the Maldives and Chagos is generated due to the combination of the ridge geometry and plume-ridge interaction. Further, the Rodrigues Ridge is formed as the surface expression
of a long-distance sublithospheric flow channel between the upwelling plume and the closest ridge segment, confirming the long-standing hypothesis of Morgan (1978) for the first time in a dynamic context. The Réunion plume has been studied in connection with the seismological
RHUM-RUM project, which has recently provided new seismic tomography images that yield an excellent match with the geodynamic model.
Regarding the Iceland plume, the numerical model shows how plume material may have accumulated in an east-west trending corridor of thin lithosphere across Greenland and resulted in simultaneous melt generation west and east of Greenland. This provides an explanation for the
extremely widespread volcanic material attributed to magma production of the Iceland hotspot and demonstrates that the model setup is also able to explain more complicated hotspot histories. The Iceland model results also agree well with newly derived seismic tomographic images.
The Kerguelen hotspot has an extremely complex history and previous studies concluded that the plume might be dismembered or influenced by solitary waves in its conduit to produce the reconstructed variable melt production rate. The geodynamic model, however, shows that a constant plume influx can result in a variable magma production rate if the plume interacts with nearby mid-ocean ridges. Moreover, the Ninetyeast Ridge in the model is created by on-ridge activities, while the Kerguelen plume was located beneath the Australian plate. This is also a contrast to earlier studies, which described the Ninetyeast Ridge as the result of the Indian plate passing over the plume. Furthermore, the Amsterdam-Saint Paul Plateau in the model is the result of plume material flowing from the upwelling toward the Southeast Indian Ridge, whereas previous geochemical studies attributed that volcanic province to a separate deep plume.
In summary, the three case studies presented in this thesis consistently highlight the importance of plume-ridge interaction in order to reconstruct the overall volcanic hotspot record as well as specific smaller features attributed to a certain hotspot. They also demonstrate that it is not necessary to attribute highly complicated properties to a specific plume in order to account for complex observations. Thus, this thesis contributes to the general understanding of plume dynamics and extends the very specific knowledge about the Réunion, Iceland, and Kerguelen mantle plumes.
Nanolenses are linear chains of differently-sized metal nanoparticles, which can theoretically provide extremely high field enhancements. The complex structure renders their synthesis challenging and has hampered closer analyses so far. Here, the technique of DNA origami was used to self-assemble DNA-coated 10 nm, 20 nm, and 60 nm gold or silver nanoparticles into gold or silver nanolenses. Three different geometrical arrangements of gold nanolenses were assembled, and for each of the three, sets of single gold nanolenses were investigated in detail by atomic force microscopy, scanning electron microscopy, dark-field scattering and Raman spectroscopy. The surface-enhanced Raman scattering (SERS) capabilities of the single nanolenses were assessed by labelling the 10 nm gold nanoparticle selectively with dye molecules. The experimental data was complemented by finite-difference time-domain simulations. For those gold nanolenses which showed the strongest field enhancement, SERS signals from the two different internal gaps were compared by selectively placing probe dyes on the 20 nm or 60 nm gold particles. The highest enhancement was found for the gap between the 20 nm and 10 nm nanoparticle, which is indicative of a cascaded field enhancement. The protein streptavidin was labelled with alkyne groups and served as a biological model analyte, bound between the 20 nm and 10 nm particle of silver nanolenses. Thereby, a SERS signal from a single streptavidin could be detected. Background peaks observed in SERS measurements on single silver nanolenses could be attributed to amorphous carbon. It was shown that the amorphous carbon is generated in situ.
The valorization of carbohydrates is one of the most promising fields in green chemistry, as it enables to produce bulk chemicals and fuels out of renewable and abundant resources, instead of further exploiting fossil feedstocks. The focus in this thesis is the conversion of fructose, using dehydration and hydrodeoxygenation reactions. The main goal is to find an easy continuous process, including the solubility of the sugar in a green solvent, the conversion over a solid acid as well as over a metal@tungsten carbide catalyst.
At the beginning of this thesis, solid acid catalysts are synthesized by using carbohydrate material like glucose and starch at high temperatures (up to 600 °C). Additionally a third carbon is synthesized, using an activation method based on Ca(OH)2. After carbonization and further sulfonation, using fuming sulfuric acid, the three resulting catalysts are characterized together with sulfonated carbon black and Amberlyst 15 as references. In order to test all solid acid catalysts in reaction, a 250 mm x 4.6 mm stainless steel column is used as a fixed-bed continuous reactor. The temperature (110 °C to 250 °C) and residence time (2 to 30 minutes) is varied, and a direct relationship between contact time and selectivity is determined. The reaction mechanism, as well as the product distribution is showing a dehydration step of fructose towards 5-hydroxymethylfurfural (HMF). These furan-ring molecules are considered as “sleeping giants”, due to the possibility of using them as fuel, but also for upgrading them to chemicals like terephthalic acid or p-xylene. Consecutive reactions are producing levulinic acid, as well as condensation products with ethanol and formic acid. The activated carbon is additionally showing a 2 % yield of 2,5-Dimethylfuran (DMF) production, pointing towards the extraordinary properties of this catalyst. Without a metal catalyst present, what is normally necessary for hydrogenation reactions, a transferhydrogenation (with formic acid) is observed. The active catalyst was therefore carbon itself, what activated the hydrogen on its surface. This phenomenon was just very rarely observed so far. Expensive noble metals are the material of choice, when it comes to hydrogenation reactions nowadays and cheaper alternatives are necessary.
By postulating a similar electronic structure of tungsten carbide (WC) to platinum by Lewy and Boudart, research is focusing on the replacement of Pt. The production of nano-sized tungsten carbide particles (7.5 ± 2.5 nm, 70 m2 g-1) is enabled by the so called “urea glass route” and its catalytic performances are compared to commercial material. It is shown, that the activity is strongly dependent on the size of the particles as well as the surface area. Nano-sized tungsten carbide is showing activity for hydrogenation reactions under mild conditions (maximum 150 °C, 30 bar). This material therefore opens up new possibilities for replacing the rare and expensive platinum with tungsten carbide based catalysts.
Additionally different metal nanoparticles of palladium, copper and nickel are deposited on top of WC to further promote its reactivity. The nickel nanoparticles are strongly connected to WC and showed the best activity as well as selectivity for upgrading HMF with hydrodeoxygenation. The Ni@WC is not leaching and is showing very good hydrodeoxygenation properties with DMF yields up to 90 percent. Copper@WC is not showing good activity and palladium@WC enables undesired consecutive reactions, hydrogenating the furan ring system.
In order to enable the upgrade of fructose to DMF directly in a continuous system, the current H CUBE Pro TM hydrogenation system is customized with a second reaction column. A 250 mm x 4.6 mm stainless steel reactor column is connected ahead of the hydrogen insertion, enabling the dehydration of fructose to HMF derivatives, before pumping these products into the second column for hydrogenation. The overall residence time in the two column reactor system is 14 minutes. The overall results are an almost full conversion with a yield of 38.5 % DMF and 47 % yield of EL. The main disadvantage is the formation of higher mass products, so called humins, which start depositing on top of the catalysts, blocking their active sites.
In general it can be stated, that a two column system goes along with a higher investment as well as more maintenance costs, compared to a one column catalytic approach. To develop a catalyst, which is on the one hand able to dehydrate as well as hydrodeoxygenate the reactants, is aimed for at the last part of the thesis. The activated carbon however shows already activity for hydrodeoxygenation without any metal present and offers itself therefore as an alternative to overcome the temperature instability of Amberlyst 15 (max. 120 °C) for a combined DMF production directly from fructose. The activity for the upgrade to DMF is increased from 2 % to 12 % DMF yield in one mixed continuous column.
In order to scale up the entire one column approach, an 800 mm x 28.5 mm inner diameter column was planned and manufactured. The system is scaled up and assembled, whereas this flow reactor system is able to be run with 50 mL min-1 maximum flow rate, to stand a pressure of maximum 100 bar and be heated to around 500 °C. The tubing and connections, as well as the used devices are planned according to be safe and easy in use. The scaled-up approach offers a reaction column 120 times bigger (510 ml) then the first extension of the commercial system. This further extension offers the possibility of ranging between 1 and 1000 mL min-1, making it possible to use the approach in pilot plant applications.
The first main goal of this thesis is to develop a concept of approximate differentiability of higher order for subsets of the Euclidean space that allows to characterize higher order rectifiable sets, extending somehow well known facts for functions. We emphasize that for every subset A of the Euclidean space and for every integer k ≥ 2 we introduce the approximate differential of order k of A and we prove it is a Borel map whose domain is a (possibly empty) Borel set. This concept could be helpful to deal with higher order rectifiable sets in applications.
The other goal is to extend to general closed sets a well known theorem of Alberti on the second order rectifiability properties of the boundary of convex bodies. The Alberti theorem provides a stratification of second order rectifiable subsets of the boundary of a convex body based on the dimension of the (convex) normal cone. Considering a suitable generalization of this normal cone for general closed subsets of the Euclidean space and employing some results from the first part we can prove that the same stratification exists for every closed set.
Introduction: Carbohydrate (CHO) and fat are the main substrates to fuel prolonged endurance exercise, each having its oxidation patterns regulated by several factors such as intensity, duration and mode of the activity, dietary intake pattern, muscle glycogen concentrations, gender and training status. Exercising at intensities where fat oxidation rates are high has been shown to induce metabolic benefits in recreational and health-oriented sportsmen. The exercise intensity (Fatpeak) eliciting peak fat oxidation rates is therefore of particular interest when aiming to prescribe exercise for the purpose of fat oxidation and related metabolic effects. Although running and walking are feasible and popular among the target population, no reliable protocols are available to assess Fatpeak as well as its actual velocity (VPFO) during treadmill ergometry. Moreover, to date, it remains unclear how pre-exercise CHO availability modulates the oxidative regulation of substrates when exercise is conducted at the intensity where the individual anaerobic threshold (IAT) is located (VIAT). That is, a metabolic marker representing the upper border where constant load endurance exercise can be sustained, being commonly used to guide athletic training or in performance diagnostics. The research objectives of the current thesis were therefore, 1) to assess the reliability and day-to-day variability of VPFO and Fatpeak during treadmill ergometry running; 2) to assess the impact of high CHO (HC) vs. low CHO (LC) diets (where on the LC day a combination of low CHO diet and a glycogen depleting exercise was implemented) on the oxidative regulation of CHOs and fat while exercise is conducted at VIAT. Methods: Research objective 1: Sixteen recreational athletes (f=7, m=9; 25 ± 3 y; 1.76 ± 0.09 m; 68.3 ± 13.7 kg; 23.1 ± 2.9 kg/m²) performed 2 different running protocols on 3 different days with standardized nutrition the day before testing. At day 1, peak oxygen uptake (VO2peak) and the velocities at the aerobic threshold (VLT) and respiratory exchange ratio (RER) of 1.00 (VRER) were assessed. At days 2 and 3, subjects ran an identical submaximal incremental test (Fat-peak test) composed of a 10 min warm-up (70% VLT) followed by 5 stages of 6 min with equal increments (stage 1 = VLT, stage 5 = VRER). Breath-by-breath gas exchange data was measured continuously and used to determine fat oxidation rates. A third order polynomial function was used to identify VPFO and subsequently Fatpeak. The reproducibility and variability of variables was verified with an intraclass correlation coefficient (ICC), Pearson’s correlation coefficient, coefficient of variation (CV) and the mean differences (bias) ± 95% limits of agreement (LoA). Research objective 2: Sixteen recreational runners (m=8, f=8; 28 ± 3 y; 1.76 ± 0.09 m; 72 ± 13 kg; 23 ± 2 kg/m²) performed 3 different running protocols, each allocated on a different day. At day 1, a maximal stepwise incremental test was implemented to assess the IAT and VIAT. During days 2 and 3, participants ran a constant-pace bout (30 min) at VIAT that was combined with randomly assigned HC (7g/kg/d) or LC (3g/kg/d) diets for the 24 h before testing. Breath-by-breath gas exchange data was measured continuously and used to determine substrate oxidation. Dietary data and differences in substrate oxidation were analyzed with a paired t-test. A two-way ANOVA tested the diet X gender interaction (α = 0.05). Results: Research objective 1: ICC, Pearson’s correlation and CV for VPFO and Fatpeak were 0.98, 0.97, 5.0%; and 0.90, 0.81, 7.0%, respectively. Bias ± 95% LoA was -0.3 ± 0.9 km/h for VPFO and -2 ± 8% of VO2peak for Fatpeak. Research objective 2: Overall, the IAT and VIAT were 2.74 ± 0.39 mmol/l and 11.1 ± 1.4 km/h, respectively. CHO oxidation was 3.45 ± 0.08 and 2.90 ± 0.07 g/min during HC and LC bouts respectively (P < 0.05). Likewise, fat oxidation was 0.13 ± 0.03 and 0.36 ± 0.03 g/min (P < 0.05). Females had 14% (P < 0.05) and 12% (P > 0.05) greater fat oxidation compared to males during HC and LC bouts, respectively. Conclusions: Research objective 1: In summary, relative and absolute reliability indicators for VPFO and Fatpeak were found to be excellent. The observed LoA may now serve as a basis for future training prescriptions, although fat oxidation rates at prolonged exercise bouts at this intensity still need to be investigated. Research objective 2: Twenty-four hours of high CHO consumption results in concurrent higher CHO oxidation rates and overall utilization, whereas maintaining a low systemic CHO availability significantly increases the contribution of fat to the overall energy metabolism. The observed gender differences underline the necessity of individualized dietary planning before exerting at intensities associated with performance exercise. Ultimately, future research should establish how these findings can be extrapolated to training and competitive situations and with that provide trainers and nutritionists with improved data to derive training prescriptions.
Background: Obesity is thought to be the consequence of an unhealthy nutrition and a lack of physical activity. Although the resulting metabolic alterations such as impaired glucose homeostasis and insulin sensitivity can usually be improved by physical activity, some obese patients fail to enhance skeletal muscle metabolic health with exercise training. Since this might be largely heritable, maternal nutrition during pregnancy and lactation is hypothesized to impair offspring skeletal muscle physiology.
Objectives: This PhD thesis aims to investigate the consequences of maternal high-fat diet (mHFD) consumption on offspring skeletal muscle physiology and exercise performance. We could show that maternal high-fat diet during gestation and lactation decreases the offspring’s training efficiency and endurance performance by influencing the epigenetic profile of their skeletal muscle and altering the adaptation to an acute exercise bout, which in long-term, increases offspring obesity susceptibility.
Experimental setup: To investigate this issue in detail, we conducted several studies with a similar maternal feeding regime. Dams (C57BL/6J) were either fed a low-fat diet (LFD; 10 energy% from fat) or high-fat diet (HFD; 40 energy% from fat) during pregnancy and lactation. After weaning, male offspring of both maternal groups were switched to a LFD, on which they remained until sacrifice in week 6, 15 or 25. In one study, LFD feeding was followed by HFD provision from week 15 until week 25 to elucidate the effects on offspring obesity susceptibility. In week 7, all mice were randomly allocated to a sedentary group (without running wheel) or an exercised group (with running wheel for voluntary exercise training). Additionally, treadmill endurance tests were conducted to investigate training performance and efficiency. In order to uncover regulatory mechanisms, each study was combined with a specific analytical setup, such as whole genome microarray analysis, gene and protein expression analysis, DNA methylation analyses, and enzyme activity assays.
Results: mHFD offspring displayed a reduced training efficiency and endurance capacity. This was not due to an altered skeletal muscle phenotype with changes in fiber size, number, and type. DNA methylation measurements in 6 week old offspring showed a hypomethylation of the Nr4a1 gene in mHFD offspring leading to an increased gene expression. Since Nr4a1 plays an important role in the regulation of skeletal muscle energy metabolism and early exercise adaptation, this could affect offspring training efficiency and exercise performance in later life.
Investigation of the acute response to exercise showed that mHFD offspring displayed a reduced gene expression of vascularization markers (Hif1a, Vegfb, etc) pointing towards a reduced angiogenesis which could possibly contribute to their reduced endurance capacity. Furthermore, an impaired glucose utilization of skeletal muscle during the acute exercise bout by an impaired skeletal muscle glucose handling was evidenced by higher blood glucose levels, lower GLUT4 translocation and diminished Lactate dehydrogenase activity in mHFD offspring immediately after the endurance test. These points towards a disturbed use of glucose as a substrate during endurance exercise. Prolonged HFD feeding during adulthood increases offspring fat mass gain in mHFD offspring compared to offspring from low-fat fed mothers and also reduces their insulin sensitivity pointing towards a higher obesity and diabetes susceptibility despite exercise training. Consequently, mHFD reduces offspring responsiveness to the beneficial effects of voluntary exercise training.
Conclusion: The results of this PhD thesis demonstrate that mHFD consumption impairs the offspring’s training efficiency and endurance capacity, and reduced the beneficial effects of exercise on the development of diet-induced obesity and insulin resistance in the offspring.
This might be due to changes in skeletal muscle epigenetic profile and/or an impaired skeletal muscle angiogenesis and glucose utilization during an acute exercise bout, which could contribute to a disturbed adaptive response to exercise training.
Import and decomposition of dissolved organic carbon in pre-dams of drinking water reservoirs
(2017)
Dissolved organic carbon (DOC) depicts a key component in the aquatic carbon cycle as well as for drinking water production from surface waters. DOC concentrations increased in water bodies of the northern hemisphere in the last decades, posing ecological consequences and water quality problems. Within the pelagic zone of lakes and reservoirs, the DOC pool is greatly affected by biological activity as DOC is simultaneously produced and decomposed. This thesis aimed for a conceptual understanding of organic carbon cycling and DOC quality changes under differing hydrological and trophic conditions. Further, the occurrence of aquatic priming was investigated, which has been proposed as a potential process facilitating the microbial decomposition of stable allochthonous DOC within the pelagic zone.
To study organic carbon cycling under different hydrological conditions, quantitative and qualitative investigations were carried out in three pre-dams of drinking water reservoirs exhibiting a gradient in DOC concentrations and trophic states. All pre-dams were mainly autotrophic in their epilimnia. Discharge and temperature were identified as the key factors regulating net production and respiration in the upper water layers of the pre-dams. Considerable high autochthonous production was observed during the summer season under higher trophic status and base flow conditions. Up to 30% of the total gained organic carbon was produced within the epilimnia. Consequently, this affected the DOC quality within the pre-dams over the year and enhanced characteristics of algae-derived DOC were observed during base flow in summer. Allochthonous derived DOC dominated at high discharges and oligotrophic conditions when production and respiration were low. These results underline that also small impoundments with typically low water residence times are hotspots of carbon cycling, significantly altering water quality in dependence of discharge conditions, temperature and trophic status. Further, it highlights that these factors need to be considered in future water management as increasing temperatures and altered precipitation patterns are predicted in the context of climate change.
Under base flow conditions, heterotrophic bacteria preferentially utilized older DOC components with a conventional radiocarbon age of 195-395 years before present (i.e. before 1950). In contrast, younger carbon components (modern, i.e. produced after 1950) were mineralized following a storm flow event. This highlights that age and recalcitrance of DOC are independent from each other. To assess the ages of the microbially consumed DOC, a simplified method was developed to recover the respired CO2 from heterotrophic bacterioplankton for carbon isotope analyses (13C, 14C). The advantages of the method comprise the operation of replicate incubations at in-situ temperatures using standard laboratory equipment and thus enabling an application in a broad range of conditions.
Aquatic priming was investigated in laboratory experiments during the microbial decomposition of two terrestrial DOC substrates (peat water and soil leachate). Thereby, natural phytoplankton served as a source of labile organic matter and the total DOC pool increased throughout the experiments due to exudation and cell lysis of the growing phytoplankton. A priming effect for both terrestrial DOC substrates was revealed via carbon isotope analysis and mixing models. Thereby, priming was more pronounced for the peat water than for the soil leachate. This indicates that the DOC source and the amount of the added labile organic matter might influence the magnitude of a priming effect. Additional analysis via high-resolution mass spectrometry revealed that oxidized, unsaturated compounds were more strongly decomposed under priming (i.e. in phytoplankton presence). Given the observed increase in DOC concentrations during the experiments, it can be concluded that aquatic priming is not easily detectable via net concentration changes alone and could be considered as a qualitative effect.
The knowledge gained from this thesis contributes to the understanding of aquatic carbon cycling and demonstrated how DOC dynamics in freshwaters vary with hydrological, seasonal and trophic conditions. It further demonstrated that aquatic priming contributes to the microbial transformation of organic carbon and the observed decay of allochthonous DOC during transport in inland waters.
During the drug discovery & development process, several phases encompassing a number of preclinical and clinical studies have to be successfully passed to demonstrate safety and efficacy of a new drug candidate. As part of these studies, the characterization of the drug's pharmacokinetics (PK) is an important aspect, since the PK is assumed to strongly impact safety and efficacy. To this end, drug concentrations are measured repeatedly over time in a study population. The objectives of such studies are to describe the typical PK time-course and the associated variability between subjects. Furthermore, underlying sources significantly contributing to this variability, e.g. the use of comedication, should be identified. The most commonly used statistical framework to analyse repeated measurement data is the nonlinear mixed effect (NLME) approach. At the same time, ample knowledge about the drug's properties already exists and has been accumulating during the discovery & development process: Before any drug is tested in humans, detailed knowledge about the PK in different animal species has to be collected. This drug-specific knowledge and general knowledge about the species' physiology is exploited in mechanistic physiological based PK (PBPK) modeling approaches -it is, however, ignored in the classical NLME modeling approach.
Mechanistic physiological based models aim to incorporate relevant and known physiological processes which contribute to the overlying process of interest. In comparison to data--driven models they are usually more complex from a mathematical perspective. For example, in many situations, the number of model parameters outrange the number of measurements and thus reliable parameter estimation becomes more complex and partly impossible. As a consequence, the integration of powerful mathematical estimation approaches like the NLME modeling approach -which is widely used in data-driven modeling -and the mechanistic modeling approach is not well established; the observed data is rather used as a confirming instead of a model informing and building input.
Another aggravating circumstance of an integrated approach is the inaccessibility to the details of the NLME methodology so that these approaches can be adapted to the specifics and needs of mechanistic modeling. Despite the fact that the NLME modeling approach exists for several decades, details of the mathematical methodology is scattered around a wide range of literature and a comprehensive, rigorous derivation is lacking. Available literature usually only covers selected parts of the mathematical methodology. Sometimes, important steps are not described or are only heuristically motivated, e.g. the iterative algorithm to finally determine the parameter estimates.
Thus, in the present thesis the mathematical methodology of NLME modeling is systemically described and complemented to a comprehensive description,
comprising the common theme from ideas and motivation to the final parameter estimation. Therein, new insights for the interpretation of different approximation methods used in the context of the NLME modeling approach are given and illustrated; furthermore, similarities and differences between them are outlined. Based on these findings, an expectation-maximization (EM) algorithm to determine estimates of a NLME model is described.
Using the EM algorithm and the lumping methodology by Pilari2010, a new approach on how PBPK and NLME modeling can be combined is presented and exemplified for the antibiotic levofloxacin. Therein, the lumping identifies which processes are informed by the available data and the respective model reduction improves the robustness in parameter estimation. Furthermore, it is shown how apriori known factors influencing the variability and apriori known unexplained variability is incorporated to further mechanistically drive the model development. Concludingly, correlation between parameters and between covariates is automatically accounted for due to the mechanistic derivation of the lumping and the covariate relationships.
A useful feature of PBPK models compared to classical data-driven PK models is in the possibility to predict drug concentration within all organs and tissue in the body. Thus, the resulting PBPK model for levofloxacin is used to predict drug concentrations and their variability within soft tissues which are the site of action for levofloxacin. These predictions are compared with data of muscle and adipose tissue obtained by microdialysis, which is an invasive technique to measure a proportion of drug in the tissue, allowing to approximate the concentrations in the interstitial fluid of tissues. Because, so far, comparing human in vivo tissue PK and PBPK predictions are not established, a new conceptual framework is derived. The comparison of PBPK model predictions and microdialysis measurements shows an adequate agreement and reveals further strengths of the presented new approach.
We demonstrated how mechanistic PBPK models, which are usually developed in the early stage of drug development, can be used as basis for model building in the analysis of later stages, i.e. in clinical studies. As a consequence, the extensively collected and accumulated knowledge about species and drug are utilized and updated with specific volunteer or patient data. The NLME approach combined with mechanistic modeling reveals new insights for the mechanistic model, for example identification and quantification of variability in mechanistic processes. This represents a further contribution to the learn & confirm paradigm across different stages of drug development.
Finally, the applicability of mechanism--driven model development is demonstrated on an example from the field of Quantitative Psycholinguistics to analyse repeated eye movement data. Our approach gives new insight into the interpretation of these experiments and the processes behind.
The goal of this thesis is related to the question how to introduce and combine simultaneously plasmonic and photoswitching properties to different nano-objects. In this thesis I investigate the complexes between noble metal nanoparticles and cationic surfactants containing azobenzene units in their hydrophobic tail, employing absorption spectroscopy, surface zeta-potential, and electron microscopy.
In the first part of the thesis, the formation of complexes between negatively charged laser ablated spherical gold nanoparticles and cationic azobenzene surfactants in trans- conformation is explored. It is shown that the constitution of the complexes strongly depends on a surfactant-to-gold molar ratio. At certain molar ratios, particle self-assembly into nanochains and their aggregation have been registered. At higher surfactant concentrations, the surface charge of nanoparticles turned positive, attributed to the formation of the stabilizing double layer of azobenzene surfactants on gold nanoparticle surfaces. These gold-surfactant complexes remained colloidally stable. UV light induced trans-cis isomerization of azobenzene surfactant molecules and thus perturbed the stabilizing surfactant shell, causing nanoparticle aggregation. The results obtained with silver and silicon nanoparticles mimick those for the comprehensively studied gold nanoparticles, corroborating the proposed model of complex formation.
In the second part, the interaction between plasmonic metal nanoparticles (Au, Ag, Pd, alloy Au-Ag, Au-Pd), as well as silicon nanoparticles, and cis-isomers of azobenzene containing compounds is addressed. Cis-trans thermal isomerization of azobenzenes was enhanced in the presence of gold, palladium, and alloy gold-palladium nanoparticles. The influence of the surfactant structure and nanoparticle material on the azobenzene isomerization rate is expounded. Gold nanoparticles showed superior catalytic activity for thermal cis-trans isomerization of azobenzenes. In a joint project with theoretical chemists, we demonstrated that the possible physical origin of this phenomenon is the electron transfer between azobenzene moieties and nanoparticle surfaces.
In the third part, complexes between gold nanorods and azobenzene surfactants with different tail length were exposed to UV and blue light, inducing trans-cis and cis-trans isomerization of surfactant, respectively. At the same time, the position of longitudinal plasmonic absorption maximum of gold nanorods experienced reversible shift responding to the changes in local dielectric environment. Surface plasmon resonance condition allowed the estimation of the refractive index of azobenzene containing surfactants in solution.
In Germany more than 200.000 persons die of cancer every year, which makes it the second most common cause of death. Chemotherapy and radiation therapy are often combined to exploit a supra-additive effect, as some chemotherapeutic agents like halogenated nucleobases sensitize the cancerous tissue to radiation. The radiosensitizing action of certain therapeutic agents can be at least partly assigned to their interaction with secondary low energy electrons (LEEs) that are generated along the track of the ionizing radiation. In the therapy of cancer DNA is an important target, as severe DNA damage like double strand breaks induce the cell death. As there is only a limited number of radiosensitizing agents in clinical practice, which are often strongly cytotoxic, it would be beneficial to get a deeper understanding of the interaction of less toxic potential radiosensitizers with secondary reactive species like LEEs. Beyond that LEEs can be generated by laser illuminated nanoparticles that are applied in photothermal therapy (PTT) of cancer, which is an attempt to treat cancer by an increase of temperature in the cells. However, the application of halogenated nucleobases in PTT has not been taken into account so far. In this thesis the interaction of the potential radiosensitizer 8-bromoadenine (8BrA) with LEEs was studied. In a first step the dissociative electron attachment (DEA) in the gas phase was studied in a crossed electron-molecular beam setup. The main fragmentation pathway was revealed as the cleavage of the C-Br bond. The formation of a stable parent anion was observed for electron energies around 0 eV. Furthermore, DNA origami nanostructures were used as platformed to determine electron induced strand break cross sections of 8BrA sensitized oligonucleotides and the corresponding nonsensitized sequence as a function of the electron energy. In this way the influence of the DEA resonances observed for the free molecules on the DNA strand breaks was examined. As the surrounding medium influences the DEA, pulsed laser illuminated gold nanoparticles (AuNPs) were used as a nanoscale electron source in an aqueous environment. The dissociation of brominated and native nucleobases was tracked with UV-Vis absorption spectroscopy and the generated fragments were identified with surface enhanced Raman scattering (SERS). Beside the electron induced damage, nucleobase analogues are decomposed in the vicinity of the laser illuminatednanoparticles due to the high temperatures. In order to get a deeper understanding of the different dissociation mechanisms, the thermal decomposition of the nucleobases in these systems was studied and the influence of the adsorption kinetics of the molecules was elucidated. In addition to the pulsed laser experiments, a dissociative electron transfer from plasmonically generated ”hot electrons” to 8BrA was observed under low energy continuous wave laser illumination and tracked with SERS. The reaction was studied on AgNPs and AuNPs as a function of the laser intensity and wavelength. On dried samples the dissociation of the molecule was described by fractal like kinetics. In solution, the dissociative electron transfer was observed as well. It turned out that the timescale of the reaction rates were slightly below typical integration times of Raman spectra. In consequence such reactions need to be taken into account in the interpretation of SERS spectra of electrophilic molecules. The findings in this thesis help to understand the interaction of brominated nucleobases with plasmonically generated electrons and free electrons. This might help to evaluate the potential radiosensitizing action of such molecules in cancer radiation therapy and PTT.
BACKGROUND: Aggressive behavior at an early age is linked to a broad range of psychosocial problems in later life. That is why risk factors of the occurrence and the development of aggression have been examined for a long time in psychological science. The present doctoral dissertation aims to expand this research by investigating risk factors in three intrapersonal domains using the prominent social-information processing approach by Crick and Dodge (1994) as a framework model. Anger regulation was examined as an affective, theory of mind as a cognitive, and physical attractiveness as an appearance-related developmental factor of aggression in middle childhood. An additional goal of this work was to develop and validate a behavioral observation assessment of anger regulation as past research lacked in ecologically valid measures of anger regulation that are applicable for longitudinal studies.
METHODS: Three empirical studies address the aforementioned intrapersonal risk factors. In each study, data from the PIER-project were used, a three-wave-longitudinal study covering three years with a total sample size of 1,657 children in the age between 6 and 11 years (at the first measurement point). The central constructs were assessed via teacher-reports (aggression), behavioral observation (anger regulation), computer tests (theory of mind), and independent ratings (physical attractiveness). The predictive value of each proposed risk factor for the development of aggressive behavior was examined via structural equation modeling.
RESULTS AND CONCLUSION: The newly developed behavioral observation measure was found to be a reliable and valid tool to assess anger regulation in middle childhood, but limited in capturing a full range of relevant regulation strategies. That might be the reason, why maladaptive anger regulation was not found to function as a risk factor of subsequent aggressive behavior. However, children’s deficits in theory of mind and a low level in physical attractiveness significantly predicted later aggression. Problematic peer relationships were identified as underlying the link between low attractiveness and aggression. Thus, fostering children’s skills in theory of mind and their ability to call existing beliefs about the nature of more versus less attractive individuals into question may be important starting points for the prevention of aggressive behavior in middle childhood.
Direct anthropogenic influences on the Earth’s subsurface during drilling, extraction or injection activities, can affect land stability by causing subsidence, uplifts or lateral displacements. They can occur in localized as well as in uninhabited and inhabited regions. Thus the associated risks for humans, infrastructure, and environment must be minimized. To achieve this, appropriate surveillance methods must be found that can be used for simultaneous monitoring during such activities. Multi-temporal synthetic aperture radar interferometry (MT-InSAR) methods like the Persistent Scatterer Interferometry (PSI) and the Small BAseline Subsets (SBAS) have been developed as standard approaches for satellite-based surface displacement monitoring. With increasing spatial resolution and availability of SAR sensors in recent years, MT-InSAR can be valuable for the detection and mapping of even the smallest man-made displacements.
This doctoral thesis aims at investigating the capacities of the mentioned standard methods for this purpose, and comprises three main objectives against the backdrop of a user-friendly surveillance service:
(1) the spatial and temporal significance assessment against leveling, (2) the suitability evaluation of PSI and SBAS under different conditions, and (3) the analysis of the link between surface motion and subsurface processes.
Two prominent case studies on anthropogenic induced subsurface processes in Germany serve as the basis for this goal. The first is the distinct urban uplift with severe damages at Staufen im Breisgau that has been associated since 2007 with a failure to implement a shallow geothermal energy supply for an individual building. The second case study considers the pilot project of geological carbon dioxide (CO2) storage at Ketzin, and comprises borehole drilling and fluid injection of more than 67 kt CO2 between 2008 and 2013. Leveling surveys at Staufen and comprehensive background knowledge of the underground processes gained from different kinds of in-situ measurements at both locations deliver a suitable basis for this comparative study and the above stated objectives. The differences in location setting, i.e. urban versus rural site character, were intended to investigate the limitations in the applicability of PSI and SBAS.
For the MT-InSAR analysis, X-band images from the German TerraSAR-X and TanDEM-X satellites were acquired in the standard Stripmap mode with about 3 m spatial resolution in azimuth and range direction. Data acquisition lasted over a period of five years for Staufen (2008-2013), and four years for Ketzin (2009-2013). For the first approximation of the subsurface source, an inversion of the InSAR outcome in Staufen was applied. The modeled uplift based on complex hydromechanical simulations and a correlation analysis with bottomhole pressure data were used for comparison with MT-InSAR measurements at Ketzin.
In response to the defined objectives of this thesis, a higher level of detail can be achieved in mapping surface displacements without in-situ effort by using MT-InSAR in comparison to leveling (1). A clear delineation of the elliptical shaped uplift border and its magnitudes at different parts was possible at Staufen, with the exception of a vegetated area in the northwest. Vegetation coverage and the associated temporal signal decorrelation are the main limitations of MT-InSAR as clearly demonstrated at the Ketzin test site. They result in insufficient measurement point density and unwrapping issues. Therefore, spatial resolutions of one meter or better are recommended to achieve an adequate point density for local displacement analysis and to apply signal noise reduction. Leveling measurements can provide a complementary data source here, but require much effort pertaining to personnel even at the local scale. Horizontal motions could be identified at Staufen by only comparing the temporal evolution of the 1D line of sight (LOS) InSAR measurements with the available leveling data. An exception was the independent LOS decomposition using ascending and descending data sets for the period 2012-2013. The full 3D displacement field representation failed due to insufficient orbit-related, north-south sensitivity of the satellite-based measurements. By using the dense temporal mapping capabilities of the TerraSAR-X/TanDEM-X satellites after every 11 days, the temporal displacement evolution could be captured as good as that with leveling.
With respect to the tested methods and in the view of generality, SBAS should be preferred over PSI (2). SBAS delivered a higher point density, and was therefore less affected by phase unwrapping issues in both case studies. Linking surface motions with subsurface processes is possible when considering simplified geophysical models (3), but it still requires intensive research to gain a deep understanding.
Plastid protein biosynthesis occurs on bacterial-type 70S ribosomes consisting of a large (50S) and a small (30S) subunit. However, since many steps of ribosome biogenesis are not thermodynamically favorable at biological conditions, it requires many assembly factors. One group of assembly factors, circularly permuted GTPases, was implicated in 30S subunit maturation in E. coli, by a protein RsgA. RsgA orthologues are present in bacteria and plastid-containing species and in silico analysis revealed presence of a RsgA-like protein in Arabidopsis thaliana. To functionally characterize the Arabidopsis orthologue, two AtRsgA T-DNA insertion lines were analyzed in this study. The exon line (rsgA-e) led to embryo lethality, while the intron line (rsgA-i) caused severe dwarf, pale green phenotype. Further investigation of rsgA-i mutant line revealed defects in chloroplast biogenesis which led to increased number of chloroplasts, decreased chloroplast size, decreased air space between mesophyll cells and smaller shoot apical meristems, which showed unusual proplastid accumulation. Moreover, rsgA-i plants showed reduction in chlorophyll A and B content, decreased electron transport rate and photosynthetic efficiency. Further analyses revealed that the protein is involved in chloroplast 30S subunit maturation. Interestingly, we observed that while chloroplast-targeted and chloroplast-encoded proteins are generally downregulated in the mutant, a contrasting upregulation of the corresponding transcripts is observed, indicating an elaborate compensatory mechanism. To conclude, the study presented here reveals a ribosome assembly factor and a compensatory mechanism activated during impaired chloroplast function.