Extern
Refine
Year of publication
Document Type
- Doctoral Thesis (126) (remove)
Is part of the Bibliography
- yes (126) (remove)
Keywords
- Arktis (6)
- Arctic (5)
- Fernerkundung (3)
- Holozän (3)
- Klimawandel (3)
- Kohlenstoff (3)
- Nanopartikel (3)
- carbon (3)
- climate change (3)
- molecular motors (3)
- molekulare Motoren (3)
- Anden (2)
- Andes (2)
- Antarctica (2)
- Antarktis (2)
- Argentina (2)
- Argentinien (2)
- Atmosphäre (2)
- E. coli (2)
- Energiespeicher (2)
- Galaxien (2)
- Geodynamik (2)
- Holocene (2)
- Kohlenstoffnitriden (2)
- Korrosion (2)
- Magnetismus (2)
- Magnetohydrodynamik (2)
- Rheologie (2)
- Rheology (2)
- Schadensmodellierung (2)
- Seesedimente (2)
- Spektroskopie (2)
- Stoffwechsel (2)
- Systembiologie (2)
- Virus (2)
- air-water interface (2)
- atmosphere (2)
- carbon nitrides (2)
- corrosion (2)
- cosmic rays (2)
- energy storage (2)
- galaxies (2)
- heterogene Photokatalyse (2)
- heterogeneous photocatalysis (2)
- kosmische Strahlung (2)
- magnetohydrodynamics (2)
- organic synthesis (2)
- organische Synthese (2)
- remote sensing (2)
- stable isotopes (2)
- stochastic processes (2)
- stochastische Prozesse (2)
- virus (2)
- 2-deoxy-D-ribose-5-phoshphate aldolase (1)
- 2D Numerical Modelling (1)
- AC Elektrokinetik (1)
- AC Elektroosmosis (1)
- AC electrokinetics (1)
- AC electroosmosis (1)
- AG "Weser" Solidarność Leninwerft (1)
- AGN (1)
- ARMS (1)
- ASPECT (1)
- Acetylcholin (1)
- Adsorption (1)
- Aerosole (1)
- Aerosols (1)
- Aktiven Galaxienkerne (1)
- Alliierte Militärverbindungsmissionen (1)
- Altiplano (1)
- Aluminiumlegierung (1)
- Aminosäuren (1)
- Anpassung (1)
- Antibiotic alternatives (1)
- Antibiotic resistance (1)
- Antibiotikaersatz (1)
- Antibiotikaresistenz (1)
- Antifouling (1)
- Antikörper (1)
- Antwortmengenprogrammierung (1)
- Application Server (1)
- Archetyp (1)
- Arctic tundra (1)
- Assemblierungsfaktor (1)
- Astronomie (1)
- Atmosphärenforschung (1)
- Atomwaffen (1)
- Aufmerksamkeit (1)
- Bakterien (1)
- Basalt-Vulkane (1)
- Bay of Bengal (1)
- Bayesian Network (1)
- Bayesianisches Netzwerk (1)
- Bayesianism (1)
- Bayesianismus (1)
- Bemessungshochwasser (1)
- Beschichtungen (1)
- Beta-Lactoglobulin (1)
- Beta-Zelle (1)
- Beweidung (1)
- Bi2Se3 (1)
- Bi2Te3 (1)
- Bindungsinteraktion (1)
- Biofilm (1)
- Biogenese (1)
- Biomoleküle (1)
- Bioraffinerie (1)
- Blattverschiebung (1)
- Boden (1)
- Borna Disease Virus (1)
- Borna disease virus (1)
- Bruchmodel (1)
- Bucht von Bengalen (1)
- Bulge (1)
- Bundesländer (1)
- Bundesnachrichtendienst (1)
- Bundeswehr (1)
- Bundeswehrkommando Ost (1)
- CCSEM (1)
- CDF (1)
- Caco-2 (1)
- Cars (1)
- Causal structure (1)
- Chaco-Paraná Becken (1)
- Chaco-Paraná basin (1)
- Chalkogenide (1)
- Chemokinematik der Milchstraße (1)
- China (1)
- Chlamydomonas (1)
- Chloroplast transformation (1)
- Chloroplastentransformation (1)
- Citrazinsäure (1)
- Clay Minerals (1)
- Climate reconstruction (1)
- Clustering (1)
- Cold War (1)
- Continental Rifts (1)
- Cu doped InP (1)
- Cu-dotiertes InP (1)
- DGVM (1)
- Data-Mining (1)
- Deformation (1)
- Deligne Cohomology (1)
- Deligne Kohomologie (1)
- Density modelling (1)
- Deoxyfructosazin (1)
- Deutschland (1)
- Diabetes (1)
- Diamantstempelzelle (1)
- Diatomeen (1)
- Diatoms (1)
- Dichtemodellierung (1)
- Dielektrophorese (1)
- Diskursverstehen (1)
- Dronning Maud Land (1)
- Durchmusterung (1)
- EKP (1)
- ERP (1)
- ETV (1)
- Earthquake (1)
- Ecology (1)
- Ecotoxicology (1)
- Einkapselung (1)
- Einzelatomkatalyse (1)
- Eisbohrkern (1)
- Ejina Basin (1)
- Ejina Becken (1)
- Electron acceleration (1)
- Elektronenbeschleunigung (1)
- Emissionslinienklassifikation (1)
- Emulsion (1)
- Entstehung der Milchstraße (1)
- Erdbeben (1)
- Erdmantel (1)
- Ereigniskorreliertes Potenzial (1)
- Europa (1)
- Europe (1)
- Evolution (1)
- Evolution der Milchstraße (1)
- Exoplaneten (1)
- Exoplanetenatmosphären (1)
- FARIMA (1)
- FastScape (1)
- Federal Armed Forces of Germany (1)
- Federal Foreign Intelligence Service (1)
- Ferroperiklas (1)
- Figurative Sprachverarbeitung (1)
- Figurative language processing (1)
- Fiskalregeln (1)
- Flache Subduktion (1)
- Flat subduction (1)
- Fluorpolymere (1)
- Foreland (1)
- Foreland basin (1)
- Foreland basins (1)
- Forstwirtschaft (1)
- Frequenzanalyse (1)
- Frucht (1)
- Fundamental Modeling Concepts (1)
- GC-MS (1)
- GIS (1)
- GITEWS (1)
- GPS (1)
- Galaxie: allgemein (1)
- Galaxienhaufen (1)
- Gasgeochemie (1)
- Gassorption (1)
- Gaxun Nur (1)
- Gen-Koexpression (1)
- Gene co-expression (1)
- Geodynamic Modelling (1)
- Geodynamics (1)
- Geodynamische Modellierung (1)
- Gerben (1)
- Gerbes (1)
- German reunification (1)
- Germany (1)
- Geschmacksrezeptor (1)
- Gleichaltrigenbeziehungen (1)
- Gletschervorfeld (1)
- Global Differentialgeometry (1)
- Globale Differentialgeometrie (1)
- Glucolipotoxizität (1)
- Glykan-Protein-Wechselwirkung (1)
- Glykopolymere (1)
- Gold (1)
- Grabenbrüche (1)
- Graphentheorie (1)
- Greenhouse Gas Emissions (1)
- Greenland (1)
- Grenzflächenchemie (1)
- Grenzschicht (1)
- Growth signaling (1)
- Gruppe der Sowjetischen Streitkräfte in Deutschland (1)
- Grönland (1)
- Grüne Chemie (1)
- Gyrochronologie (1)
- HMA (1)
- Harnstoff-Glas-Route (1)
- Hauptfaserbündel (1)
- Heavy Minerals (1)
- Heihe (1)
- HepG2 (1)
- Heptazine (1)
- Herkunftsanalyse (1)
- Hochdruck (1)
- Hochwasserrisiko (1)
- Holonomie (1)
- Holonomy (1)
- Horizontal flux (1)
- Hyperakkumulation (1)
- Hysterese (1)
- IBM 360 (1)
- ICP OES (1)
- ICT competencies (1)
- IRF3 (1)
- Immunoassay (1)
- Impakt (1)
- Importin (1)
- InSAR (1)
- Indian Summer Monsoon (1)
- Indischer Sommermonsun (1)
- Influenza (1)
- Informatikdidaktik (1)
- Informatische Kompetenzen (1)
- Inlandeis (1)
- Instrumente: Polarimeter (1)
- Instrumente: Spektrographen (1)
- Intelligence history (1)
- Interactors (1)
- Interaktoren (1)
- Interferon <beta-> (1)
- Introgression (1)
- Inversion (1)
- Ionenmobilitätspektrometrie (1)
- Java 2 Enterprise Edition (1)
- Java Virtual Machine (1)
- Jets (1)
- Kalter Krieg (1)
- Karbonnitrid Ionothermalsynthese (1)
- Kathode (1)
- Kausalstruktur (1)
- Kernlokalisierungssignal (1)
- Klimaphysik (1)
- Klimarekonstruktion (1)
- Klimavariabilität (1)
- Kognition (1)
- Kohlenstoffhaushalt (1)
- Kohlenstoffkreislauf (1)
- Kohlenstoffmaterialien (1)
- Kohlenstoffmodell (1)
- Kohnen (1)
- Kompetenzen (1)
- Kultivierung (1)
- LAEs (1)
- LOC (1)
- LPJ (1)
- Lake sediments (1)
- Laser ablation (1)
- Lateglacial (1)
- Lavafontänen (1)
- Lektine (1)
- Li-Batterien (1)
- Li-Ionen-Akkus (1)
- Li-Ionen-Kondensator (1)
- Li-batteries (1)
- Li-ion batteries (1)
- Li-ion capacitor (1)
- LiFePO4 (1)
- Lidar (1)
- Lignin (1)
- Lokalisierung von Deformation (1)
- Lyman Kontinuum (1)
- Lyman alpha (1)
- Lyman continuum (1)
- Lyman-Alpha-Emitter (1)
- Lyman-alpha emitters (1)
- Lysimeter (1)
- MTP (1)
- MTP1 (1)
- MTP2 (1)
- MTP3 (1)
- Macht (1)
- Magnetfelder (1)
- Magnetoelastizität (1)
- Markov chains (1)
- Markov-Prozesse (1)
- Markovketten (1)
- Massenspektrometrie (1)
- Mechanobiologie (1)
- Meereis (1)
- Mesokristalle (1)
- Mesoporosity (1)
- Mesoporosität (1)
- Metabolism (1)
- Metabolit (1)
- Metabolome (1)
- Meteorologie (1)
- Microschwimmer (1)
- Mikrofluidik (1)
- Mikrokapseln (1)
- Mikroplatte (1)
- Mikrowellensynthese (1)
- Militärgeschichte (1)
- Milky Way chemo-kinematics (1)
- Milky Way evolution (1)
- Milky Way formation (1)
- Mitochondrien (1)
- Modeling (1)
- Modellierung (1)
- Mondsee (1)
- Morphologie von Kapseln (1)
- Muttergalaxien (1)
- NZO (1)
- Nachrichtendienstgeschichte (1)
- Nano (1)
- Nanoelektroden (1)
- Natrium-Ionen-Akkumulator (1)
- Neutronensterne (1)
- Nichtlineare Spektroskopie (1)
- Nichtlineare Wellen (1)
- Nicotin (1)
- Nitrat (1)
- Nitride (1)
- Nitrides (1)
- Nonlinear waves (1)
- Nuklearwaffen (1)
- Numerische 2D Modellierung (1)
- Oberflächenbeschichtung (1)
- Oberflächenchemie (1)
- Oberflächenprozesse (1)
- Oberflächenzustände (1)
- OpenStreetMap (1)
- Orogen (1)
- Oscillating Bubble (1)
- Oxinitride (1)
- Oxynitrides (1)
- P-Typ ATPase (1)
- PAVM (1)
- PBCEC (1)
- PHREEQC (1)
- PM10, PM2, PM1 (1)
- POC (1)
- PUFA (1)
- Paleofloods (1)
- Paläohochwasser (1)
- Paläoklima (1)
- Paläolimnologie (1)
- Permafrost (1)
- Permafrostdegradation (1)
- Permafrostsedimente (1)
- Perowskite (1)
- Phage lysins (1)
- Phagenlysine (1)
- Phosphatidylethanolamin (1)
- Phosphatidylserin (1)
- Phosphatidylserin Decarboxylase (1)
- Phospholipide (1)
- Phosphoproteomik (1)
- Photochemische Reaktionen (1)
- Photosynthese (1)
- Photosystem I (1)
- Pkw (1)
- Pollen (1)
- Polyether (1)
- Polymerisation (1)
- Polymernetzwerk (1)
- Polyneuropathie (1)
- Popularity (1)
- Populationsdynamik (1)
- Power (1)
- Pragmatik (1)
- Prinicipal Fibre Bundles (1)
- Procrustes rotation analysis (1)
- Prokrustes Analyse (1)
- Propeller (1)
- Proteom (1)
- Protonenleitfähigkeit (1)
- Provenance Analysis (1)
- Proxyunsicherheit (1)
- Proxyverständnis (1)
- Pseudodatensätze (1)
- Puna (1)
- QD device (1)
- QD stability (1)
- QD-Gerät (1)
- QD-Stabilität (1)
- QtClassify (1)
- RAVE Beobachtungskampagne (1)
- RAVE survey (1)
- Reionisierung (1)
- Relativistische Astrophysik (1)
- Remote Sensing (1)
- Rezeptor (1)
- Rift (1)
- Rotation (1)
- Russian Arctic (1)
- Röntgenbeugung (1)
- Röntgenkleinwinkelstreuung (1)
- SAR (1)
- SEGUE Beobachtungskampagne (1)
- SEGUE survey (1)
- SFA (1)
- Salzgestein (1)
- Salzschmelze (1)
- Salzschmelze-Templating (1)
- Schaum (1)
- Scheibe (1)
- Schiffbau (1)
- Schlüsselkompetenzen (1)
- Schuldenbremse (1)
- Schwerminerale (1)
- Segmentierung (1)
- Seismologie (1)
- Selbstheilende Beschichtungen (1)
- Selen (1)
- Selenonein (1)
- Shock waves (1)
- Shortening (1)
- Sierras Pampeanas (1)
- Silika (1)
- Simulationen (1)
- Social Status (1)
- Sociometry (1)
- Solar corona (1)
- Sonne: Oszillationen (1)
- Sonne: Sonnenflecken (1)
- Sonnenkorona (1)
- Soziale Ungleichheit (1)
- Sozialer Status (1)
- Soziometrie (1)
- Spalteneruption (1)
- Spannungsfeld (1)
- Spinpolarisation (1)
- Spionage (1)
- Split Ubiquitin (1)
- Spätglazial (1)
- Staatsverschuldung (1)
- Stabile Isotope (1)
- Stabilität (1)
- Stakeholder-based Science (1)
- Stakeholder-basierte Forschung (1)
- Stalagmiten (1)
- Statistik (1)
- Stern-Planeten-Wechselwirkung (1)
- Sterne: Entfernungen (1)
- Sternphysik (1)
- Stickstoff (1)
- Stimuli-Sensitivität (1)
- Stoßwellen (1)
- Strain Localisation (1)
- Strukturgeologie (1)
- Styrol (1)
- Subduction (1)
- Subduktion (1)
- Sulfation (1)
- Sun: oszillations (1)
- Sun: sunspots (1)
- Supernovaüberreste (1)
- Synthese (1)
- Synthesis (1)
- Systeme interagierender Partikel (1)
- Systems Biology (1)
- TBK1 (1)
- TRPV1 (1)
- Tabak (1)
- Target of Rapamycin kinase (1)
- Tas1r1 (1)
- Tauziehen (1)
- Tektonik (1)
- Temperaturproxy (1)
- Templatphase (1)
- Tensid (1)
- Thermokarstprozesse (1)
- Thylakoidmembran (1)
- Tibet Plateau (1)
- Tibetan Plateau (1)
- Tomate (1)
- Tomato (1)
- Tonminerale (1)
- Torsion Experiments (1)
- Torsionsexperimente (1)
- Treibhausgasemissionen (1)
- Triazin (1)
- Truppenabzug (1)
- Tsunami (1)
- Turbulenz (1)
- Unsicherheiten (1)
- Unsicherheitsanalyse (1)
- Urea-Glas-Route (1)
- VLT/MUSE (1)
- VM (1)
- VM Integration (1)
- VOC (1)
- Vegetation (1)
- Vegetationsmodell (1)
- Verkürzung (1)
- Vertical flux (1)
- Videoanalyse (1)
- Virtuelle Maschine (1)
- Vorland (1)
- Vorlandbecken (1)
- Vulkan Verformung (1)
- Vulkanologie (1)
- Vulnerabilität (1)
- Wachstumssignale (1)
- Warven (1)
- Warves (1)
- Wasser-Gesteins-Wechselwirkungen (1)
- Wasser/Luft Grenzflächen (1)
- Wasserhaushalt (1)
- Weitwinkelröntgenstreuung (1)
- West-Ost Vergleich (1)
- Westgruppe der Truppen (1)
- Wiedervereinigung (1)
- Windböen (1)
- Winderosion (1)
- Wärmefluss (1)
- Wärmekapazität (1)
- X-ray diffraction (1)
- Zink (1)
- Zirkulardichroismus (1)
- Zyklone (1)
- Züchtung (1)
- acoustically levitated droplets (1)
- active galactic nuclei (1)
- actylcholine (1)
- adaptation (1)
- adipose tissue (1)
- adsorption (1)
- aktive Galaxienkerne (1)
- akustisch schwebende Tropfen (1)
- allied military liaison missions (1)
- aluminum alloy (1)
- amino acids (1)
- anaerobe Inkubationensexperimente (1)
- anaerobic incubation experiments (1)
- angle resolved photoelectron spectroscopy (1)
- anisotrop (1)
- anisotropic (1)
- answer set programming (1)
- antibody (1)
- antimicrobial (1)
- archetype (1)
- arctic (1)
- arktische Tundra (1)
- assembly factor (1)
- astronomy (1)
- atmospheric science (1)
- attention (1)
- bacteria (1)
- basaltic volcanoes (1)
- beta-cell (1)
- bidirectional intracellular transport (1)
- bidirektionaler intrazellulärer Transport (1)
- bild (1)
- binding interactions (1)
- biofilm (1)
- biogenesis (1)
- biomolecule (1)
- biorefinery (1)
- black holes (1)
- boundary layer (1)
- breeding (1)
- bulge (1)
- cancer cachexia (1)
- capsule morphology (1)
- carbon cycle (1)
- carbon cycling (1)
- carbon materials (1)
- carbon nitride (1)
- cathode (1)
- central Andes (1)
- central-eastern Beringia (1)
- chalcogenide (1)
- chemokines (1)
- chlorbenzol (1)
- chronic pain (1)
- chronischer Schmerz (1)
- circular dichroism (1)
- citrazinic acid (1)
- climate physics (1)
- clustering (1)
- coating (1)
- cognition (1)
- colloidal quantum dot (1)
- competencies (1)
- complex emulsion (1)
- complex systems (1)
- computer science education (CSE) (1)
- consolidation (1)
- cooperative phenomena (1)
- cooperative transport (1)
- covalent frameworks (1)
- critical collapse (1)
- crops (1)
- cultivation (1)
- cyclones (1)
- cytokines (1)
- damage modeling (1)
- damage modelling (1)
- data-mining (1)
- debt brake (1)
- deep eutectic solvents (1)
- density-driven flow (1)
- deoxyfructosazine (1)
- diabetes (1)
- diamond anvil cell (1)
- dichlorbenzol (1)
- dichlorobenzene (1)
- dichtegetriebene Strömung (1)
- dielectrophoresis (1)
- disc (1)
- discourse comprehension (1)
- dünne Filme (1)
- earth mantle (1)
- economic impacts (1)
- elastic coupling (1)
- elastische Kopplung (1)
- emission line classification (1)
- employment precariousness (1)
- emulsion (1)
- encapsulation (1)
- energy metabolism (1)
- enzymatically active membrane (1)
- enzyme immobilization (1)
- enzyme/polymer conjugate (1)
- espionage, Intelligence (1)
- event-related potentials (1)
- exoplanet atmospheres (1)
- exoplanets (1)
- expandierbar (1)
- expansion (1)
- family (1)
- ferropericlase (1)
- firn (1)
- fiscal rules (1)
- fissure eruption (1)
- flood risk (1)
- fluorinated polymers (1)
- foam (1)
- forestry (1)
- formate assimilation (1)
- frequency analysis (1)
- fruit (1)
- fundamental parameters (1)
- fundamentale Parameter (1)
- galactic astronomy (1)
- galaktische Astronomie (1)
- galaxy clusters (1)
- galaxy: general (1)
- gas geochemistry (1)
- gas sorption (1)
- gender (1)
- general education in computer science (1)
- geodynamics (1)
- geothermal exploration (1)
- geothermal monitoring (1)
- geothermische Exploration (1)
- geothermische Überwachung (1)
- glacier forefield (1)
- global change (1)
- global labour history (1)
- glucolipotoxicity (1)
- glycan-protein interaction (1)
- glycopolymers (1)
- gold (1)
- governance (1)
- grafting-from (1)
- graph theory (1)
- grazing (1)
- green chemistry (1)
- group of Soviet forces in Germany (1)
- großräumige Struktur des Universums (1)
- gyrochronology (1)
- heat capacity (1)
- heat flux (1)
- heptazine (1)
- heteroatom-doped carbons (1)
- heteroatom-dotierte Kohlenstoffe (1)
- heterogene Katalyse (1)
- heterogeneous catalysis (1)
- hierarchical porosity (1)
- hierarchische Porosität (1)
- high pressure (1)
- high resolution (1)
- high-redshift (1)
- hohe Auflösung (1)
- hoher Rotverschiebung (1)
- horizontaler Fluss (1)
- host galaxies (1)
- hydro-meteorological risk (1)
- hydro-meteorologische Risiken (1)
- hyperaccumulation (1)
- hyperspectral remote sensing (1)
- hyperspektral Fernerkundung (1)
- hysteresis (1)
- ice core (1)
- ice sheet (1)
- image (1)
- imaging spectroscopy (1)
- immunoassay (1)
- impact (1)
- importin (1)
- inflammation (1)
- influenza (1)
- informatische Allgemeinbildung (1)
- instrumentation: polarimeters (1)
- instrumentation: spectrographs (1)
- interacting particle systems (1)
- intracellular transport (1)
- intracluster medium (1)
- intrazellulärer Transport (1)
- inversion (1)
- ion mobility spectrometry (1)
- ionothermal synthesis (1)
- isotope variations (1)
- key competencies (1)
- kolloidaler Quantenpunkt (1)
- komplexe Emulsion (1)
- komplexe Systeme (1)
- kooperative Phänomene (1)
- kooperativer Transport (1)
- kovalente Rahmenbedingungen (1)
- kritischer Kollaps (1)
- lab-on-chip (1)
- lake sediments (1)
- langreichweitige Korrelationen (1)
- large-scale structure (1)
- lava fountains (1)
- layered compounds (1)
- lebende Materialien (1)
- lectins (1)
- light-programmable viscosity (1)
- lignin (1)
- living materials (1)
- logical signaling networks (1)
- logische Signalnetzwerke (1)
- long-memory (1)
- long-range dependence (1)
- lubricant (1)
- lysimeter (1)
- ländliche Entwicklung (1)
- lösungsmittelfreie Synthese (1)
- machine learning (1)
- magnetic fields (1)
- magnetism (1)
- magnetoelasticity (1)
- markov processes (1)
- maschinelles Lernen (1)
- mass spectrometry (1)
- mechanobiology (1)
- medical (1)
- medizinisch (1)
- mehrfache Stressfaktoren (1)
- mehrschichtige Verbindungen (1)
- mesocrystals (1)
- mesoporous (1)
- mesoporös (1)
- metabolic engineering (1)
- metabolic genomics (1)
- metabolism (1)
- metabolite breeding (1)
- metabolite profiling (1)
- metabolome (1)
- meteorology (1)
- methanol assimilation (1)
- miRNA (1)
- microbial communities (1)
- microcapsules (1)
- microfluidics (1)
- microplate (1)
- microswimmers (1)
- microwave synthesis (1)
- mikrobielle Gemeinschaften (1)
- military history (1)
- mitochondria (1)
- mock data catalogues (1)
- molecular biomarkers (1)
- molekulare Biomarker (1)
- monochlorobenzene (1)
- multiple stress factors (1)
- multiresponsiv (1)
- multiresponsive (1)
- nachhaltige Energiespeichermaterialien (1)
- nanoelectrodes (1)
- nanoparticle (1)
- nanoparticles (1)
- neutron stars (1)
- nichtgenestete Modellselektion (1)
- nicotine (1)
- nitrate (1)
- nitrogen (1)
- noise (1)
- non-nested model selection (1)
- nonlinear optics (1)
- nuclear localization signal (1)
- nuclear weapons (1)
- numerical astrophysics (1)
- numerical modelling (1)
- numerical relativity (1)
- numerische Astrophysik (1)
- numerische Modellierung (1)
- numerische Relativitätstheorie (1)
- ob/ob (1)
- offene Daten (1)
- open data (1)
- optical properties (1)
- optische Eigenschaften (1)
- organic matter (1)
- organisches Material (1)
- oscillating bubble (1)
- p-type ATPase (1)
- palaeoclimate (1)
- paleolimnology (1)
- peer relations (1)
- periglacial landscape evolution (1)
- periglacial landscapes (1)
- periglaziale Landschaften (1)
- periglaziale Landschaftsentwicklung (1)
- permafrost (1)
- permafrost degradation (1)
- permafrost sediments (1)
- perovskite (1)
- phosphatidylethanolamine (1)
- phosphatidylserine (1)
- phosphatidylserine decarboxylase (1)
- phospholipids (1)
- phosphoproteomics (1)
- photochemical reactions (1)
- photosynthesis (1)
- photosystem I (1)
- plant secondary metabolites (1)
- point-of-care (1)
- politics of production shipyards (1)
- polymer network (1)
- polymerization (1)
- polyneuropathy (1)
- population dynamics (1)
- porous materials (1)
- porous polymers (1)
- poröse Materialien (1)
- poröse Polymere (1)
- post-depositional (1)
- pragmatics (1)
- probabilistic approach (1)
- probabilistischer Ansatz (1)
- programmable friction (1)
- propellers (1)
- protein (1)
- proteome (1)
- proton conductivity (1)
- proxy uncertainty (1)
- proxy understanding (1)
- public finance (1)
- quasiparticle interactions (1)
- rational choice (1)
- reactive transport (1)
- reaktiver Transport (1)
- receptor (1)
- reionization (1)
- relativistic hydrodynamics (1)
- relativistische Hydrodynamik (1)
- return level estimation (1)
- rift (1)
- rising bubble (1)
- rotation (1)
- rural development (1)
- russische Arktis (1)
- räumlich explizit (1)
- räumliche Analyse (1)
- salt melt (1)
- salt melt templating (1)
- salt rock (1)
- schwarze Löcher (1)
- sea ice (1)
- segmentation (1)
- seismology (1)
- sekundäre Pflanzenstoffe (1)
- selenium (1)
- selenoneine (1)
- self-assembly (1)
- self-healing coatings (1)
- self-rated health (1)
- shipbuildung (1)
- silica nanoparticles (1)
- simulation (1)
- single-atom catalysis (1)
- small-angle x-ray scattering (1)
- sodium-ion batteries (1)
- soft and hard templating (1)
- soil (1)
- solvent-free reactions (1)
- source model (1)
- spatial analyses (1)
- spatially explicit (1)
- spectroscopy (1)
- spin resolved photoelectron spectroscopy (1)
- spin-orbit coupling (1)
- spinaufgelöste Photoelektronenspektroskopie (1)
- spindown (1)
- spiropyran copolymer (1)
- stabile Isotope (1)
- stabile Schichtung (1)
- stability (1)
- stable stratification (1)
- stalagmites (1)
- star-planet interaction (1)
- stark eutektisches Lösungsmittel (1)
- stars: distances (1)
- statistical physics (1)
- statistics (1)
- statistische Physik (1)
- steigende Blasen (1)
- stellar content (1)
- stellar physics (1)
- stellarer Inhalt (1)
- stimuli-sensitivity (1)
- stress field (1)
- strike-slip (1)
- structural geology (1)
- styrene (1)
- supercritical carbon dioxide (scCO₂) (1)
- supernova remnants (1)
- surface chemistry (1)
- surface modification (1)
- surface processes (1)
- surface rheology (1)
- surface states (1)
- surfactants (1)
- survey (1)
- sustainable energy storage materials (1)
- switchSENSE (1)
- switchSENSE Technologie (1)
- systems biology (1)
- taste receptor (1)
- tectonics (1)
- temperature proxy (1)
- temperature variability (1)
- template phase (1)
- thermokarst processes (1)
- thin films (1)
- thylakoid membranes (1)
- time reversal symmetry (1)
- tobacco (1)
- topological insulators (1)
- topologische Isolatoren (1)
- transition metals (1)
- triazine (1)
- tug-of-war (1)
- turbulence (1)
- two-dimensional (1)
- ultrafast (1)
- ultraschnell (1)
- umami (1)
- uncertainty (1)
- uncertainty analysis (1)
- unemployment (1)
- vegetation (1)
- vegetation model (1)
- verbal irony (1)
- verbale Ironie (1)
- vertikaler Fluss (1)
- video analysis (1)
- volcano deformation (1)
- volcanology (1)
- vulnerability (1)
- water balance (1)
- water rock interactions (1)
- weiche und harte Templatierung (1)
- welfare and gender regimes (1)
- west-east comparison (1)
- western group of forces (1)
- wide-angle x-ray scattering (1)
- wind gusts (1)
- winderosion (1)
- winkelaufgelöste Photoelektronenspektroskopie (1)
- withdrawal of troops (1)
- zentral-östliches Beringia (1)
- zentralen Anden (1)
- zinc (1)
- Ökologie (1)
- Ökotoxikologie (1)
- Übergangsmetalle (1)
- ökonomische Auswirkungen (1)
- überkritisches Kohlendioxid (scCO₂) (1)
Institute
- Extern (126)
- Institut für Chemie (29)
- Institut für Geowissenschaften (29)
- Institut für Physik und Astronomie (27)
- Institut für Biochemie und Biologie (18)
- Institut für Ernährungswissenschaft (5)
- Historisches Institut (3)
- Institut für Informatik und Computational Science (2)
- Institut für Mathematik (2)
- Wirtschaftswissenschaften (2)
The utilization of lignin as renewable electrode material for electrochemical energy storage is a sustainable approach for future batteries and supercapacitors. The composite electrode was fabricated from Kraft lignin and conductive carbon and the charge storage contribution was determined in terms of electrical double layer (EDL) and redox reactions. The important factors at play for achieving high faradaic charge storage capacity contribute to high surface area, accessibility of redox sites in lignin and their interaction with conductive additives. A thinner layer of lignin covering the high surface area of carbon facilitates the electron transfer process with a shorter pathway from the active sites of nonconductive lignin to the current collector leading to the improvement of faradaic charge storage capacity.
Composite electrodes from lignin and carbon would be even more sustainable if the fluorinated binder can be omitted. A new route to fabricate a binder-free composite electrode from Kraft lignin and high surface area carbon has been proposed by crosslinking lignin with glyoxal. A high molecular weight of lignin is obtained to enhance both electroactivity and binder capability in composite electrodes. The order of the processing step of crosslinking lignin on the composite electrode plays a crucial role in achieving a stable electrode and high charge storage capacity. The crosslinked lignin based electrodes are promising since they allow for more stable, sustainable, halogen-free and environmentally benign devices for energy storage applications. Furthermore, improvement of the amount of redox active groups (quinone groups) in lignin is useful to enhance the capacity in lithium battery applications. Direct oxidative demethylation by cerium ammonium nitrate has been carried out under mild conditions. This proves that an increase of quinone groups is able to enhance the performance of lithium battery. Thus, lignin is a promising material and could be a good candidate for application in sustainable energy storage devices.
Adsorption layers of soluble surfactants enable and govern a variety of phenomena in surface and colloidal sciences, such as foams. The ability of a surfactant solution to form wet foam lamellae is governed by the surface dilatational rheology. Only systems having a non-vanishing imaginary part in their surface dilatational modulus, E, are able to form wet foams. The aim of this thesis is to illuminate the dissipative processes that give rise to the imaginary part of the modulus. There are two controversial models discussed in the literature. The reorientation model assumes that the surfactants adsorb in two distinct states, differing in their orientation. This model is able to describe the frequency dependence of the modulus E. However, it assumes reorientation dynamics in the millisecond time regime. In order to assess this model, we designed a SHG pump-probe experiment that addresses the orientation dynamics. Results obtained reveal that the orientation dynamics occur in the picosecond time regime, being in strong contradiction with the two states model. The second model regards the interface as an interphase. The adsorption layer consists of a topmost monolayer and an adjacent sublayer. The dissipative process is due to the molecular exchange between both layers. The assessment of this model required the design of an experiment that discriminates between the surface compositional term and the sublayer contribution. Such an experiment has been successfully designed and results on elastic and viscoelastic surfactant provided evidence for the correctness of the model. Because of its inherent surface specificity, surface SHG is a powerful analytical tool that can be used to gain information on molecular dynamics and reorganization of soluble surfactants. They are central elements of both experiments. However, they impose several structural elements of the model system. During the course of this thesis, a proper model system has been identified and characterized. The combination of several linear and nonlinear optical techniques, allowed for a detailed picture of the interfacial architecture of these surfactants.
Supernovae are known to be the dominant energy source for driving turbulence in the interstellar medium. Yet, their effect on magnetic field amplification in spiral galaxies is still poorly understood. Analytical models based on the uncorrelated-ensemble approach predicted that any created field will be expelled from the disk before a significant amplification can occur. By means of direct simulations of supernova-driven turbulence, we demonstrate that this is not the case. Accounting for vertical stratification and galactic differential rotation, we find an exponential amplification of the mean field on timescales of 100Myr. The self-consistent numerical verification of such a “fast dynamo” is highly beneficial in explaining the observed strong magnetic fields in young galaxies. We, furthermore, highlight the importance of rotation in the generation of helicity by showing that a similar mechanism based on Cartesian shear does not lead to a sustained amplification of the mean magnetic field. This finding impressively confirms the classical picture of a dynamo based on cyclonic turbulence.
This thesis is focussed on the electronic properties of the new material class named topological insulators. Spin and angle resolved photoelectron spectroscopy have been applied to reveal several unique properties of the surface state of these materials. The first part of this thesis introduces the methodical background of these quite established experimental techniques.
In the following chapter, the theoretical concept of topological insulators is introduced. Starting from the prominent example of the quantum Hall effect, the application of topological invariants to classify material systems is illuminated. It is explained how, in presence of time reversal symmetry, which is broken in the quantum Hall phase, strong spin orbit coupling can drive a system into a topologically non trivial phase. The prediction of the spin quantum Hall effect in two dimensional insulators an the generalization to the three dimensional case of topological insulators is reviewed together with the first experimental realization of a three dimensional topological insulator in the Bi1-xSbx alloys given in the literature.
The experimental part starts with the introduction of the Bi2X3 (X=Se, Te) family of materials. Recent theoretical predictions and experimental findings on the bulk and surface electronic structure of these materials are introduced in close discussion to our own experimental results. Furthermore, it is revealed, that the topological surface state of Bi2Te3 shares its orbital symmetry with the bulk valence band and the observation of a temperature induced shift of the chemical potential is to a high probability unmasked as a doping effect due to residual gas adsorption.
The surface state of Bi2Te3 is found to be highly spin polarized with a polarization value of about 70% in a macroscopic area, while in Bi2Se3 the polarization appears reduced, not exceeding 50%. We, however, argue that the polarization is most likely only extrinsically limited in terms of the finite angular resolution and the lacking detectability of the out of plane component of the electron spin. A further argument is based on the reduced surface quality of the single crystals after cleavage and, for Bi2Se3 a sensitivity of the electronic structure to photon exposure.
We probe the robustness of the topological surface state in Bi2X3 against surface impurities in Chapter 5. This robustness is provided through the protection by the time reversal symmetry. Silver, deposited on the (111) surface of Bi2Se3 leads to a strong electron doping but the surface state is observed up to a deposited Ag mass equivalent to one atomic monolayer. The opposite sign of doping, i.e., hole-like, is observed by exposing oxygen to Bi2Te3. But while the n-type shift of Ag on Bi2Se3 appears to be more or less rigid, O2 is lifting the Dirac point of the topological surface state in Bi2Te3 out of the valence band minimum at $\Gamma$. After increasing the oxygen dose further, it is possible to shift the Dirac point to the Fermi level, while the valence band stays well beyond. The effect is found reversible, by warming up the samples which is interpreted in terms of physisorption of O2.
For magnetic impurities, i.e., Fe, we find a similar behavior as for the case of Ag in both Bi2Se3 and Bi2Te3. However, in that case the robustness is unexpected, since magnetic impurities are capable to break time reversal symmetry which should introduce a gap in the surface state at the Dirac point which in turn removes the protection. We argue, that the fact that the surface state shows no gap must be attributed to a missing magnetization of the Fe overlayer. In Bi2Te3 we are able to observe the surface state for deposited iron mass equivalents in the monolayer regime. Furthermore, we gain control over the sign of doping through the sample temperature during deposition.
Chapter6 is devoted to the lifetime broadening of the photoemission signal from the topological surface states of Bi2Se3 and Bi2Te3. It is revealed that the hexagonal warping of the surface state in Bi2Te3 introduces an anisotropy for electrons traveling along the two distinct high symmetry directions of the surface Brillouin zone, i.e., $\Gamma$K and $\Gamma$M. We show that the phonon coupling strength to the surface electrons in Bi2Te3 is in nice agreement with the theoretical prediction but, nevertheless, higher than one may expect. We argue that the electron-phonon coupling is one of the main contributions to the decay of photoholes but the relatively small size of the Fermi surface limits the number of phonon modes that may scatter off electrons. This effect is manifested in the energy dependence of the imaginary part of the electron self energy of the surface state which shows a decay to higher binding energies in contrast to the monotonic increase proportional to E$^2$ in the Fermi liquid theory due to electron-electron interaction.
Furthermore, the effect of the surface impurities of Chapter 5 on the quasiparticle life- times is investigated. We find that Fe impurities have a much stronger influence on the lifetimes as compared to Ag. Moreover, we find that the influence is stronger independently of the sign of the doping. We argue that this observation suggests a minor contribution of the warping on increased scattering rates in contrast to current belief. This is additionally confirmed by the observation that the scattering rates increase further with increasing silver amount while the doping stays constant and by the fact that clean Bi2Se3 and Bi2Te3 show very similar scattering rates regardless of the much stronger warping in Bi2Te3.
In the last chapter we report on a strong circular dichroism in the angle distribution of the photoemission signal of the surface state of Bi2Te3. We show that the color pattern obtained by calculating the difference between photoemission intensities measured with opposite photon helicity reflects the pattern expected for the spin polarization. However, we find a strong influence on strength and even sign of the effect when varying the photon energy. The sign change is qualitatively confirmed by means of one-step photoemission calculations conducted by our collaborators from the LMU München, while the calculated spin polarization is found to be independent of the excitation energy. Experiment and theory together unambiguously uncover the dichroism in these systems as a final state effect and the question in the title of the chapter has to be negated: Circular dichroism in the angle distribution is not a new spin sensitive technique.
This PhD thesis presents the spatio-temporal distribution of terrestrial carbon fluxes for the time period of 1982 to 2002 simulated by a combination of the process-based dynamic global vegetation model LPJ and a 21-year time series of global AVHRR-fPAR data (fPAR – fraction of photosynthetically active radiation). Assimilation of the satellite data into the model allows improved simulations of carbon fluxes on global as well as on regional scales. As it is based on observed data and includes agricultural regions, the model combined with satellite data produces more realistic carbon fluxes of net primary production (NPP), soil respiration, carbon released by fire and the net land-atmosphere flux than the potential vegetation model. It also produces a good fit to the interannual variability of the CO2 growth rate. Compared to the original model, the model with satellite data constraint produces generally smaller carbon fluxes than the purely climate-based stand-alone simulation of potential natural vegetation, now comparing better to literature estimates. The lower net fluxes are a result of a combination of several effects: reduction in vegetation cover, consideration of human influence and agricultural areas, an improved seasonality, changes in vegetation distribution and species composition. This study presents a way to assess terrestrial carbon fluxes and elucidates the processes contributing to interannual variability of the terrestrial carbon exchange. Process-based terrestrial modelling and satellite-observed vegetation data are successfully combined to improve estimates of vegetation carbon fluxes and stocks. As net ecosystem exchange is the most interesting and most sensitive factor in carbon cycle modelling and highly uncertain, the presented results complementary contribute to the current knowledge, supporting the understanding of the terrestrial carbon budget.
Ziel der Studie war die Untersuchung individueller und familialer Faktoren für den sozialen Status eines Kindes in seiner Schulklasse. Durch die Unterscheidung von Akzeptanz und Einfluss als zweier Hauptdimensionen des sozialen Status konnte die Arbeit aufklären, welche Rolle verschiedene Attribute für das Erreichen von Akzeptanz oder Einfluss spielen. 234 Dritt- und Fünftklässler aus Berliner Grundschulen erhielten soziometrische Maße, durch welche der soziale Status erhoben wurde (Akzeptanz und Einfluss). Individuelle und familiale Faktoren wurden mittels Peernominationen über das Verhalten der Kinder (Fremdurteil), Schulnoten (Lehrerangabe)und Maße des sozio-ökonomischen Status der Eltern (Elternangabe)erhoben. Die Ergebnisse zeigen, dass Akzeptanz positiv mit prosozialem und negativ mit aggressivem Verhalten eines Kindes assoziiert ist. Die Zusammenhänge dieser Verhaltensweisen mit Einfluss wiesen in dieselbe Richtung, waren aber deutlich geringer. Ideenreichtum und Humor hingen mit Akzeptanz und Einfluss gleichermaßen positiv zusammen, sowie Traurigsein gleichermaßen negativ mit beiden Statusdimensionen verbunden war. Das Verhalten eines Kindes vermittelte den Zusammenhang zwischen Merkmalen wie Geschlecht, relativem Alter, Schulnoten und der Akzeptanz und dem Einfluss eines Kindes. Zum Beispiel war die positive Beziehung zwischen Schulnoten und dem sozialen Status überwiegend auf die mit(guten)Schulnoten assoziierten Verhaltensweisen Prosozialität und (geringe) Aggressivität zurückzuführen. Die größere Akzeptanz von Mädchen ließ sich ebenso durch deren größere Prosozialität und geringere Aggressivität erklären. Jungen waren im Hinblick auf ihren Einfluss sowohl am oberen als auch am unteren Ende der Hierarchie überrepräsentiert. Sowohl sehr einflussreiche als auch einflusslose Jungen zeichneten sich durch eine erhöhte Aggressivität aus. Komplexere Analysen wiesen daraufhin, dass Jungen negative Auswirkungen von aggressivem Verhalten durch Humor und Ideenreichtum auf ihren Status kompensieren konnten. Der moderate Zusammenhang zwischen dem elterlichen sozioökonomischen Status und dem sozialen Status des Kindes wurde vollständig durch das Verhalten des Kindes mediiert. Das Elternhaus war wichtiger für die Akzeptanz als für den Einfluss eines Kindes. Kinder mit Migrationshintergrund waren sowohl weniger akzeptiert als auch weniger einflussreich in ihrer Klasse. Elterliche Trennung trug nicht zur sozialen Position eines Kindes bei.
Major challenges during geothermal exploration and exploitation include the structural-geological characterization of the geothermal system and the application of sustainable monitoring concepts to explain changes in a geothermal reservoir during production and/or reinjection of fluids. In the absence of sufficiently permeable reservoir rocks, faults and fracture networks are preferred drilling targets because they can facilitate the migration of hot and/or cold fluids. In volcanic-geothermal systems considerable amounts of gas emissions can be released at the earth surface, often related to these fluid-releasing structures.
In this thesis, I developed and evaluated different methodological approaches and measurement concepts to determine the spatial and temporal variation of several soil gas parameters to understand the structural control on fluid flow. In order to validate their potential as innovative geothermal exploration and monitoring tools, these methodological approaches were applied to three different volcanic-geothermal systems. At each site an individual survey design was developed regarding the site-specific questions.
The first study presents results of the combined measurement of CO2 flux, ground temperatures, and the analysis of isotope ratios (δ13CCO2, 3He/4He) across the main production area of the Los Humeros geothermal field, to identify locations with a connection to its supercritical (T > 374◦C and P > 221 bar) geothermal reservoir. The results of the systematic and large-scale (25 x 200 m) CO2 flux scouting survey proved to be a fast and flexible way to identify areas of anomalous degassing. Subsequent sampling with high resolution surveys revealed the actual extent and heterogenous pattern of anomalous degassing areas. They have been related to the internal fault hydraulic architecture and allowed to assess favourable structural settings for fluid flow such as fault intersections. Finally, areas of unknown structurally controlled permeability with a connection to the superhot geothermal reservoir have been determined, which represent promising targets for future geothermal exploration and development.
In the second study, I introduce a novel monitoring approach by examining the variation of CO2 flux to monitor changes in the reservoir induced by fluid reinjection. For that reason, an automated, multi-chamber CO2 flux system was deployed across the damage zone of a major normal fault crossing the Los Humeros geothermal field. Based on the results of the CO2 flux scouting survey, a suitable site was selected that had a connection to the geothermal reservoir, as identified by hydrothermal CO2 degassing and hot ground temperatures (> 50 °C). The results revealed a response of gas emissions to changes in reinjection rates within 24 h, proving an active hydraulic communication between the geothermal reservoir and the earth surface. This is a promising monitoring strategy that provides nearly real-time and in-situ data about changes in the reservoir and allows to timely react to unwanted changes (e.g., pressure decline, seismicity).
The third study presents results from the Aluto geothermal field in Ethiopia where an area-wide and multi-parameter analysis, consisting of measurements of CO2 flux, 222Rn, and 220Rn activity concentrations and ground temperatures was conducted to detect hidden permeable structures. 222Rn and 220Rn activity concentrations are evaluated as a complementary soil gas parameter to CO2 flux, to investigate their potential to understand tectono-volcanic degassing. The combined measurement of all parameters enabled to develop soil gas fingerprints, a novel visualization approach. Depending on the magnitude of gas emissions and their migration velocities the study area was divided in volcanic (heat), tectonic (structures), and volcano-tectonic dominated areas. Based on these concepts, volcano-tectonic dominated areas, where hot hydrothermal fluids migrate along permeable faults, present the most promising targets for future geothermal exploration and development in this geothermal field. Two of these areas have been identified in the south and south-east which have not yet been targeted for geothermal exploitation. Furthermore, two unknown areas of structural related permeability could be identified by 222Rn and 220Rn activity concentrations.
Eventually, the fourth study presents a novel measurement approach to detect structural controlled CO2 degassing, in Ngapouri geothermal area, New Zealand. For the first time, the tunable diode laser (TDL) method was applied in a low-degassing geothermal area, to evaluate its potential as a geothermal exploration method. Although the sampling approach is based on profile measurements, which leads to low spatial resolution, the results showed a link between known/inferred faults and increased CO2 concentrations. Thus, the TDL method proved to be a successful in the determination of structural related permeability, also in areas where no obvious geothermal activity is present. Once an area of anomalous CO2 concentrations has been identified, it can be easily complemented by CO2 flux grid measurements to determine the extent and orientation of the degassing segment.
With the results of this work, I was able to demonstrate the applicability of systematic and area-wide soil gas measurements for geothermal exploration and monitoring purposes. In particular, the combination of different soil gases using different measurement networks enables the identification and characterization of fluid-bearing structures and has not yet been used and/or tested as standard practice. The different studies present efficient and cost-effective workflows and demonstrate a hands-on approach to a successful and sustainable exploration and monitoring of geothermal resources. This minimizes the resource risk during geothermal project development. Finally, to advance the understanding of the complex structure and dynamics of geothermal systems, a combination of comprehensive and cutting-edge geological, geochemical, and geophysical exploration methods is essential.
The central gas in half of all galaxy clusters shows short cooling times. Assuming unimpeded cooling, this should lead to high star formation and mass cooling rates, which are not observed. Instead, it is believed that condensing gas is accreted by the central black hole that powers an active galactic nuclei jet, which heats the cluster. The detailed heating mechanism remains uncertain. A promising mechanism invokes cosmic ray protons that scatter on self-generated magnetic fluctuations, i.e. Alfvén waves. Continuous damping of Alfvén waves provides heat to the intracluster medium. Previous work has found steady state solutions for a large sample of clusters where cooling is balanced by Alfvénic wave heating. To verify modeling assumptions, we set out to study cosmic ray injection in three-dimensional magnetohydrodynamical simulations of jet feedback in an idealized cluster with the moving-mesh code arepo. We analyze the interaction of jet-inflated bubbles with the turbulent magnetized intracluster medium.
Furthermore, jet dynamics and heating are closely linked to the largely unconstrained jet composition. Interactions of electrons with photons of the cosmic microwave background result in observational signatures that depend on the bubble content. Those recent observations provided evidence for underdense bubbles with a relativistic filling while adopting simplifying modeling assumptions for the bubbles. By reproducing the observations with our simulations, we confirm the validity of their modeling assumptions and as such, confirm the important finding of low-(momentum) density jets.
In addition, the velocity and magnetic field structure of the intracluster medium have profound consequences for bubble evolution and heating processes. As velocity and magnetic fields are physically coupled, we demonstrate that numerical simulations can help link and thereby constrain their respective observables. Finally, we implement the currently preferred accretion model, cold accretion, into the moving-mesh code arepo and study feedback by light jets in a radiatively cooling magnetized cluster. While self-regulation is attained independently of accretion model, jet density and feedback efficiencies, we find that in order to reproduce observed cold gas morphology light jets are preferred.
Cosmic rays (CRs) constitute an important component of the interstellar medium (ISM) of galaxies and are thought to play an essential role in governing their evolution. In particular, they are able to impact the dynamics of a galaxy by driving galactic outflows or heating the ISM and thereby affecting the efficiency of star-formation. Hence, in order to understand galaxy formation and evolution, we need to accurately model this non-thermal constituent of the ISM. But except in our local environment within the Milky Way, we do not have the ability to measure CRs directly in other galaxies. However, there are many ways to indirectly observe CRs via the radiation they emit due to their interaction with magnetic and interstellar radiation fields as well as with the ISM.
In this work, I develop a numerical framework to calculate the spectral distribution of CRs in simulations of isolated galaxies where a steady-state between injection and cooling is assumed. Furthermore, I calculate the non-thermal emission processes arising from the modelled CR proton and electron spectra ranging from radio wavelengths up to the very high-energy gamma-ray regime.
I apply this code to a number of high-resolution magneto-hydrodynamical (MHD) simulations of isolated galaxies, where CRs are included. This allows me to study their CR spectra and compare them to observations of the CR proton and electron spectra by the Voyager-1 satellite and the AMS-02 instrument in order to reveal the origin of the measured spectral features.
Furthermore, I provide detailed emission maps, luminosities and spectra of the non-thermal emission from our simulated galaxies that range from dwarfs to Milk-Way analogues to starburst galaxies at different evolutionary stages. I successfully reproduce the observed relations between the radio and gamma-ray luminosities with the far-infrared (FIR) emission of star-forming (SF) galaxies, respectively, where the latter is a good tracer of the star-formation rate. I find that highly SF galaxies are close to the limit where their CR population would lose all of their energy due to the emission of radiation, whereas CRs tend to escape low SF galaxies more quickly. On top of that, I investigate the properties of CR transport that are needed in order to match the observed gamma-ray spectra.
Furthermore, I uncover the underlying processes that enable the FIR-radio correlation (FRC) to be maintained even in starburst galaxies and find that thermal free-free-emission naturally explains the observed radio spectra in SF galaxies like M82 and NGC 253 thus solving the riddle of flat radio spectra that have been proposed to contradict the observed tight FRC.
Lastly, I scrutinise the steady-state modelling of the CR proton component by investigating for the first time the influence of spectrally resolved CR transport in MHD simulations on the hadronic gamma-ray emission of SF galaxies revealing new insights into the observational signatures of CR transport both spectrally and spatially.
Natural extreme events are an integral part of nature on planet earth. Usually these events are only considered hazardous to humans, in case they are exposed. In this case, however, natural hazards can have devastating impacts on human societies. Especially hydro-meteorological hazards have a high damage potential in form of e.g. riverine and pluvial floods, winter storms, hurricanes and tornadoes, which can occur all over the globe. Along with an increasingly warm climate also an increase in extreme weather which potentially triggers natural hazards can be expected. Yet, not only changing natural systems, but also changing societal systems contribute to an increasing risk associated with these hazards. These can comprise increasing exposure and possibly also increasing vulnerability to the impacts of natural events. Thus, appropriate risk management is required to adapt all parts of society to existing and upcoming risks at various spatial scales. One essential part of risk management is the risk assessment including the estimation of the economic impacts. However, reliable methods for the estimation of economic impacts due to hydro-meteorological hazards are still missing. Therefore, this thesis deals with the question of how the reliability of hazard damage estimates can be improved, represented and propagated across all spatial scales. This question is investigated using the specific example of economic impacts to companies as a result of riverine floods in Germany.
Flood damage models aim to describe the damage processes during a given flood event. In other words they describe the vulnerability of a specific object to a flood. The models can be based on empirical data sets collected after flood events. In this thesis tree-based models trained with survey data are used for the estimation of direct economic flood impacts on the objects. It is found that these machine learning models, in conjunction with increasing sizes of data sets used to derive the models, outperform state-of-the-art damage models. However, despite the performance improvements induced by using multiple variables and more data points, large prediction errors remain at the object level. The occurrence of the high errors was explained by a further investigation using distributions derived from tree-based models. The investigation showed that direct economic impacts to individual objects cannot be modeled by a normal distribution. Yet, most state-of-the-art approaches assume a normal distribution and take mean values as point estimators. Subsequently, the predictions are unlikely values within the distributions resulting in high errors. At larger spatial scales more objects are considered for the damage estimation. This leads to a better fit of the damage estimates to a normal distribution. Consequently, also the performance of the point estimators get better, although large errors can still occur due to the variance of the normal distribution. It is recommended to use distributions instead of point estimates in order to represent the reliability of damage estimates.
In addition current approaches also mostly ignore the uncertainty associated with the characteristics of the hazard and the exposed objects. For a given flood event e.g. the estimation of the water level at a certain building is prone to uncertainties. Current approaches define exposed objects mostly by the use of land use data sets. These data sets often show inconsistencies, which introduce additional uncertainties. Furthermore, state-of-the-art approaches also imply problems of missing consistency when predicting the damage at different spatial scales. This is due to the use of different types of exposure data sets for model derivation and application. In order to face these issues a novel object-based method was developed in this thesis. The method enables a seamless estimation of hydro-meteorological hazard damage across spatial scales including uncertainty quantification. The application and validation of the method resulted in plausible estimations at all spatial scales without overestimating the uncertainty.
Mainly newly available data sets containing individual buildings make the application of the method possible as they allow for the identification of flood affected objects by overlaying the data sets with water masks. However, the identification of affected objects with two different water masks revealed huge differences in the number of identified objects. Thus, more effort is needed for their identification, since the number of objects affected determines the order of magnitude of the economic flood impacts to a large extent.
In general the method represents the uncertainties associated with the three components of risk namely hazard, exposure and vulnerability, in form of probability distributions. The object-based approach enables a consistent propagation of these uncertainties in space. Aside from the propagation of damage estimates and their uncertainties across spatial scales, a propagation between models estimating direct and indirect economic impacts was demonstrated. This enables the inclusion of uncertainties associated with the direct economic impacts within the estimation of the indirect economic impacts. Consequently, the modeling procedure facilitates the representation of the reliability of estimated total economic impacts. The representation of the estimates' reliability prevents reasoning based on a false certainty, which might be attributed to point estimates. Therefore, the developed approach facilitates a meaningful flood risk management and adaptation planning.
The successful post-event application and the representation of the uncertainties qualifies the method also for the use for future risk assessments. Thus, the developed method enables the representation of the assumptions made for the future risk assessments, which is crucial information for future risk management. This is an important step forward, since the representation of reliability associated with all components of risk is currently lacking in all state-of-the-art methods assessing future risk.
In conclusion, the use of object-based methods giving results in the form of distributions instead of point estimations is recommended. The improvement of the model performance by the means of multi-variable models and additional data points is possible, but small. Uncertainties associated with all components of damage estimation should be included and represented within the results. Furthermore, the findings of the thesis suggest that, at larger scales, the influence of the uncertainty associated with the vulnerability is smaller than those associated with the hazard and exposure. This leads to the conclusion that for an increased reliability of flood damage estimations and risk assessments, the improvement and active inclusion of hazard and exposure, including their uncertainties, is needed in addition to the improvements of the models describing the vulnerability of the objects.
The highly conserved protein complex containing the Target of Rapamycin (TOR) kinase is known to integrate intra- and extra-cellular stimuli controlling nutrient allocation and cellular growth. This thesis describes three studies aimed to understand how TOR signaling pathway influences carbon and nitrogen metabolism in Chlamydomonas reinhardtii. The first study presents a time-resolved analysis of the molecular and physiological features across the diurnal cycle. The inhibition of TOR leads to 50% reduction in growth followed by nonlinear delays in the cell cycle progression. The metabolomics analysis showed that the growth repression is mainly driven by differential carbon partitioning between anabolic and catabolic processes. Furthermore, the high accumulation of nitrogen-containing compounds indicated that TOR kinase controls the carbon to nitrogen balance of the cell, which is responsible for biomass accumulation, growth and cell cycle progression. In the second study the cause of the high accumulation of amino acids is explained. For this purpose, the effect of TOR inhibition on Chlamydomonas was examined under different growth regimes using stable 13C- and 15N-isotope labeling. The data clearly showed that an increased nitrogen uptake is induced within minutes after the inhibition of TOR. Interestingly, this increased N-influx is accompanied by increased activities of nitrogen assimilating enzymes. Accordingly, it was concluded that TOR inhibition induces de-novo amino acid synthesis in Chlamydomonas. The recognition of this novel process opened an array of questions regarding potential links between central metabolism and TOR signaling. Therefore a detailed phosphoproteomics study was conducted to identify the potential substrates of TOR pathway regulating central metabolism. Interestingly, some of the key enzymes involved in carbon metabolism as well as amino acid synthesis exhibited significant changes in the phosphosite intensities immediately after TOR inhibition. Altogether, these studies provide a) detailed insights to metabolic response of Chlamydomonas to TOR inhibition, b) identification of a novel process causing rapid upshifts in amino acid levels upon TOR inhibition and c) finally highlight potential targets of TOR signaling regulating changes in central metabolism. Further biochemical and molecular investigations could confirm these observations and advance the understanding of growth signaling in microalgae.
In this thesis we mainly generalize two theorems from Mackaay-Picken and Picken (2002, 2004). In the first paper, Mackaay and Picken show that there is a bijective correspondence between Deligne 2-classes $\xi \in \check{H}^2(M,\mathcal{D}^2)$ and holonomy maps from the second thin-homotopy group $\pi_2^2(M)$ to $U(1)$. In the second one, a generalization of this theorem to manifolds with boundaries is given: Picken shows that there is a bijection between Deligne 2-cocycles and a certain variant of 2-dimensional topological quantum field theories. In this thesis we show that these two theorems hold in every dimension. We consider first the holonomy case, and by using simplicial methods we can prove that the group of smooth Deligne $d$-classes is isomorphic to the group of smooth holonomy maps from the $d^{th}$ thin-homotopy group $\pi_d^d(M)$ to $U(1)$, if $M$ is $(d-1)$-connected. We contrast this with a result of Gajer (1999). Gajer showed that Deligne $d$-classes can be reconstructed by a different class of holonomy maps, which not only include holonomies along spheres, but also along general $d$-manifolds in $M$. This approach does not require the manifold $M$ to be $(d-1)$-connected. We show that in the case of flat Deligne $d$-classes, our result differs from Gajers, if $M$ is not $(d-1)$-connected, but only $(d-2)$-connected. Stiefel manifolds do have this property, and if one applies our theorem to these and compare the result with that of Gajers theorem, it is revealed that our theorem reconstructs too many Deligne classes. This means, that our reconstruction theorem cannot live without the extra assumption on the manifold $M$, that is our reconstruction needs less informations about the holonomy of $d$-manifolds in $M$ at the price of assuming $M$ to be $(d-1)$-connected. We continue to show, that also the second theorem can be generalized: By introducing the concept of Picken-type topological quantum field theory in arbitrary dimensions, we can show that every Deligne $d$-cocycle induces such a $d$-dimensional field theory with two special properties, namely thin-invariance and smoothness. We show that any $d$-dimensional topological quantum field theory with these two properties gives rise to a Deligne $d$-cocycle and verify that this construction is surjective and injective, that is both groups are isomorphic.
Spatial and temporal temperature and moisture patterns across the Tibetan Plateau are very complex. The onset and magnitude of the Holocene climate optimum in the Asian monsoon realm, in particular, is a subject of considerable debate as this time period is often used as an analogue for recent global warming. In the light of contradictory inferences regarding past climate and environmental change on the Tibetan Plateau, I have attempted to explain mismatches in the timing and magnitude of change. Therefore, I analysed the temporal variation of fossil pollen and diatom spectra and the geochemical record from palaeo-ecological records covering different time scales (late Quaternary and the last 200 years) from two core regions in the NE and SE Tibetan Plateau. For interpretation purposes I combined my data with other available palaeo-ecological data to set up corresponding aquatic and terrestrial proxy data sets of two lake pairs and two sets of sites. I focused on the direct comparison of proxies representing lacustrine response to climate signals (e.g., diatoms, ostracods, geochemical record) and proxies representing changes in the terrestrial environment (i.e., terrestrial pollen), in order to asses whether the lake and its catchments respond at similar times and magnitudes to environmental changes. Therefore, I introduced the established numerical technique procrustes rotation as a new approach in palaeoecology to quantitatively compare raw data of any two sedimentary records of interest in order to assess their degree of concordance. Focusing on the late Quaternary, sediment cores from two lakes (Kuhai Lake 35.3°N; 99.2°E; 4150 m asl; and Koucha Lake 34.0°N; 97.2°E; 4540 m asl) on the semi-arid northeastern Tibetan Plateau were analysed to identify post-glacial vegetation and environmental changes, and to investigate the responses of lake ecosystems to such changes. Based on the pollen record, five major vegetation and climate changes could be identified: (1) A shift from alpine desert to alpine steppe indicates a change from cold, dry conditions to warmer and more moist conditions at 14.8 cal. ka BP, (2) alpine steppe with tundra elements points to conditions of higher effective moisture and a stepwise warming climate at 13.6 cal. ka BP, (3) the appearance of high-alpine meadow vegetation indicates a further change towards increased moisture, but with colder temperatures, at 7.0 cal. ka BP, (4) the reoccurrence of alpine steppe with desert elements suggests a return to a significantly colder and drier phase at 6.3 cal. ka BP, and (5) the establishment of alpine steppe-meadow vegetation indicates a change back to relatively moist conditions at 2.2 cal. ka BP. To place the reconstructed climate inferences from the NE Tibetan Plateau into the context of Holocene moisture evolution across the Tibetan Plateau, I applied a five-scale moisture index and average link clustering to all available continuous pollen and non-pollen palaeoclimate records from the Tibetan Plateau, in an attempt to detect coherent regional and temporal patterns of moisture evolution on the Plateau. However, no common temporal or spatial pattern of moisture evolution during the Holocene could be detected, which can be assigned to the complex responses of different proxies to environmental changes in an already very heterogeneous mountain landscape, where minor differences in elevation can result in marked variations in microenvironments. Focusing on the past 200 years, I analysed the sedimentary records (LC6 Lake 29.5°N, 94.3°E, 4132 m asl; and Wuxu Lake 29.9°N, 101.1°E, 3705 m asl) from the southeastern Tibetan Plateau. I found that despite presumed significant temperature increases over that period, pollen and diatom records from the SE Tibetan Plateau reveal only very subtle changes throughout their profiles. The compositional species turnover investigated over the last 200 years appears relatively low in comparison to the species reorganisations during the Holocene. The results indicate that climatically induced ecological thresholds are not yet crossed, but that human activity has an increasing influence, particularly on the terrestrial ecosystem. Forest clearances and reforestation have not caused forest decline in our study area, but a conversion of natural forests to semi-natural secondary forests. The results from the numerical proxy comparison of the two sets of two pairs of Tibetan lakes indicate that the use of different proxies and the work with palaeo-ecological records from different lake types can cause deviant stories of inferred change. Irrespective of the timescale (Holocene or last 200 years) or region (SE or NE Tibetan Plateau) analysed, the agreement in terms of the direction, timing, and magnitude of change between the corresponding terrestrial data sets is generally better than the match between the corresponding lacustrine data sets, suggesting that lacustrine proxies may partly be influenced by in-lake or local catchment processes whereas the terrestrial proxy reflects a more regional climatic signal. The current disaccord on coherent temporal and spatial climate patterns on the Tibetan Plateau can partly be ascribed to the complexity of proxy response and lake systems on the Tibetan Plateau. Therefore, a multi-proxy, multi-site approach is important in order to gain a reliable climate interpretation for the complex mountain landscape of the Tibetan Plateau.
Deciphering the functioning of biological networks is one of the central tasks in systems biology. In particular, signal transduction networks are crucial for the understanding of the cellular response to external and internal perturbations. Importantly, in order to cope with the complexity of these networks, mathematical and computational modeling is required. We propose a computational modeling framework in order to achieve more robust discoveries in the context of logical signaling networks. More precisely, we focus on modeling the response of logical signaling networks by means of automated reasoning using Answer Set Programming (ASP). ASP provides a declarative language for modeling various knowledge representation and reasoning problems. Moreover, available ASP solvers provide several reasoning modes for assessing the multitude of answer sets. Therefore, leveraging its rich modeling language and its highly efficient solving capacities, we use ASP to address three challenging problems in the context of logical signaling networks: learning of (Boolean) logical networks, experimental design, and identification of intervention strategies. Overall, the contribution of this thesis is three-fold. Firstly, we introduce a mathematical framework for characterizing and reasoning on the response of logical signaling networks. Secondly, we contribute to a growing list of successful applications of ASP in systems biology. Thirdly, we present a software providing a complete pipeline for automated reasoning on the response of logical signaling networks.
One aspect of achieving a more sustainable chemical industry is the minimization of the usage of solvents and chemicals. Thus, optimization and development of chemical processes for large-scale production is favourably performed in small batches. The critical step in this approach is upscaling the batches from the small reaction systems to the large reactors mandatory for cost efficient production in an industrial environment. Scaling up the bulk volume always goes along with increasing the surface where the reaction medium is in contact with the confining vessel. Since volume scales proportional with the cubic dimension while the surface scales quadratic, their ratio is size-dependent. The influence of reaction vessel walls can change the reaction performance. A number of phenomena occurring at the surface-liquid interface can affect reaction rates and yields, resulting in possible difficulties in predicting and extrapolating from small size production scale to large industrial processes. The application of levitated droplets as a containerless reaction vessels provides a promising possibility to avoid the above-mentioned issues.
In the presented work, an efficient coupling of acoustically levitated droplets to an ion mobility (IM) spectrometer, operating at ambient conditions, was designed for real-time monitoring of chemical reactions. The design of the system comprises noncontact sampling and ionization of the droplet realised by laser desorption/ionization at 2,94 µm. The scope of the work includes fundamental studies covering understanding of laser irradiation of droplets enclosed in an acoustical field. Understanding of this phenomenon is crucial to comprehending the effects of temporal and spatial resolution of the generated ion plume that influence the resolution of the system.
The set-up includes an acoustic trap, laser irradiation and ion manipulation electrostatic lenses operating at high voltage at ambient pressure. The complexity of the design needs to fully be considered for an effective ion transfer at the interface region between the levitated droplet and IM spectrometer. For sampling and ionization, two distinct laser pulse lengths were evaluated, ns and µs. Irradiation via µs laser pulses provides several advantages: i) the droplet volume is not extensively impinged, as in case of ns laser pulses, allowing the sampling of only the small volume of the droplet; ii) the lower fluence results in less pronounced oscillations of the droplet confined in the acoustic field. The droplet will not be dissipated out of the acoustic field leading to loss of the sample; iii) the mild laser irradiation results in better spatial and temporal ion plume confinement, leading to better resolution of the detected ion packets. Finally, this knowledge allows the application of ion optics necessary to induce ion flow between the droplet suspended in the acoustic field and the IM spectrometer. The ion optics, composed of 2 electrostatic lenses placed in the near vicinity of the droplet, allow effective focusing of the ion plume and its redirection directly to the IM spectrometer entrance. This novel coupling has proved to be successful for detection of some simple molecules ionizable at the 2.94 µm wavelength. To further demonstrate the applicability of the system, a proof-of-principle reaction was selected, fulfilling the requirements of the system, and was subjected to comprehensive investigation of its performance. Herein, the reaction between N-Boc cysteine methyl ester and allyl alcohol has been performed in a batch reactor and on-line monitored via 1H NMR to establish reaction propagation. With the additional assessment, it was confirmed that the thiol-ene coupling can be performed within first 20 minutes of the irradiation with a reaction yield above 50%, proving that the reaction can be applied as a study case to assess the possibilities of the developed system.
Reactive eutectic media based on ammonium formate for the valorization of bio-sourced materials
(2023)
In the last several decades eutectic mixtures of different compositions were successfully used as solvents for vast amount of chemical processes, and only relatively recently they were discovered to be widely spread in nature. As such they are discussed as a third liquid media of the living cell, that is composed of common cell metabolites. Such media may also incorporate water as a eutectic component in order to regulate properties such as enzyme activity or viscosity. Taking inspiration form such sophisticated use of eutectic mixtures, this thesis will explore the use of reactive eutectic media (REM) for organic synthesis. Such unconventional media are characterized by the reactivity of their components, which means that mixture may assume the role of the solvent as well as the reactant itself.
The thesis focuses on novel REM based on ammonium formate and investigates their potential for the valorization of bio-sourced materials. The use of REM allows the performance of a number of solvent-free reactions, which entails the benefits of a superior atom and energy economy, higher yields and faster rates compared to reactions in solution. This is evident for the Maillard reaction between ammonium formate and various monosaccharides for the synthesis of substituted pyrazines as well as for a Leuckart type reaction between ammonium formate and levulinic acid for the synthesis of 5-methyl-2-pyrrolidone. Furthermore, reaction of ammonium formate with citric acid for the synthesis of yet undiscovered fluorophores, shows that synthesis in REM can open up unexpected reaction pathways.
Another focus of the thesis is the study of water as a third component in the REM. As a result, the concept of two different dilution regimes (tertiary REM and in REM in solvent) appears useful for understanding the influence of water. It is shown that small amounts of water can be of great benefit for the reaction, by reducing viscosity and at the same time increasing reaction yields.
REM based on ammonium formate and organic acids are employed for lignocellulosic biomass treatment. The thesis thereby introduces an alternative approach towards lignocellulosic biomass fractionation that promises a considerable process intensification by the simultaneous generation of cellulose and lignin as well as the production of value-added chemicals from REM components. The thesis investigates the generated cellulose and the pathway to nanocellulose generation and also includes the structural analysis of extracted lignin.
Finally, the thesis investigates the potential of microwave heating to run chemical reactions in REM and describes the synergy between these two approaches. Microwave heating for chemical reactions and the use of eutectic mixtures as alternative reaction media are two research fields that are often described in the scope of green chemistry. The thesis will therefore also contain a closer inspection of this terminology and its greater goal of sustainability.
The echo chamber model describes the development of groups in heterogeneous social networks. By heterogeneous social network we mean a set of individuals, each of whom represents exactly one opinion. The existing relationships between individuals can then be represented by a graph. The echo chamber model is a time-discrete model which, like a board game, is played in rounds. In each round, an existing relationship is randomly and uniformly selected from the network and the two connected individuals interact. If the opinions of the individuals involved are sufficiently similar, they continue to move closer together in their opinions, whereas in the case of opinions that are too far apart, they break off their relationship and one of the individuals seeks a new relationship. In this paper we examine the building blocks of this model. We start from the observation that changes in the structure of relationships in the network can be described by a system of interacting particles in a more abstract space.
These reflections lead to the definition of a new abstract graph that encompasses all possible relational configurations of the social network. This provides us with the geometric understanding necessary to analyse the dynamic components of the echo chamber model in Part III. As a first step, in Part 7, we leave aside the opinions of the inidividuals and assume that the position of the edges changes with each move as described above, in order to obtain a basic understanding of the underlying dynamics. Using Markov chain theory, we find upper bounds on the speed of convergence of an associated Markov chain to its unique stationary distribution and show that there are mutually identifiable networks that are not apparent in the dynamics under analysis, in the sense that the stationary distribution of the associated Markov chain gives equal weight to these networks.
In the reversible cases, we focus in particular on the explicit form of the stationary distribution as well as on the lower bounds of the Cheeger constant to describe the convergence speed.
The final result of Section 8, based on absorbing Markov chains, shows that in a reduced version of the echo chamber model, a hierarchical structure of the number of conflicting relations can be identified.
We can use this structure to determine an upper bound on the expected absorption time, using a quasi-stationary distribution. This hierarchy of structure also provides a bridge to classical theories of pure death processes. We conclude by showing how future research can exploit this link and by discussing the importance of the results as building blocks for a full theoretical understanding of the echo chamber model. Finally, Part IV presents a published paper on the birth-death process with partial catastrophe. The paper is based on the explicit calculation of the first moment of a catastrophe. This first part is entirely based on an analytical approach to second degree recurrences with linear coefficients. The convergence to 0 of the resulting sequence as well as the speed of convergence are proved. On the other hand, the determination of the upper bounds of the expected value of the population size as well as its variance and the difference between the determined upper bound and the actual value of the expected value. For these results we use almost exclusively the theory of ordinary nonlinear differential equations.
The advent of large-scale and high-throughput technologies has recently caused a shift in focus in contemporary biology from decades of reductionism towards a more systemic view. Alongside the availability of genome sequences the exploration of organisms utilizing such approach should give rise to a more comprehensive understanding of complex systems. Domestication and intensive breeding of crop plants has led to a parallel narrowing of their genetic basis. The potential to improve crops by conventional breeding using elite cultivars is therefore rather limited and molecular technologies, such as marker assisted selection (MAS) are currently being exploited to re-introduce allelic variance from wild species. Molecular breeding strategies have mostly focused on the introduction of yield or resistance related traits to date. However given that medical research has highlighted the importance of crop compositional quality in the human diet this research field is rapidly becoming more important. Chemical composition of biological tissues can be efficiently assessed by metabolite profiling techniques, which allow the multivariate detection of metabolites of a given biological sample. Here, a GC/MS metabolite profiling approach has been applied to investigate natural variation of tomatoes with respect to the chemical composition of their fruits. The establishment of a mass spectral and retention index (MSRI) library was a prerequisite for this work in order to establish a framework for the identification of metabolites from a complex mixture. As mass spectral and retention index information is highly important for the metabolomics community this library was made publicly available. Metabolite profiling of tomato wild species revealed large differences in the chemical composition, especially of amino and organic acids, as well as on the sugar composition and secondary metabolites. Intriguingly, the analysis of a set of S. pennellii introgression lines (IL) identified 889 quantitative trait loci of compositional quality and 326 yield-associated traits. These traits are characterized by increases/decreases not only of single metabolites but also of entire metabolic pathways, thus highlighting the potential of this approach in uncovering novel aspects of metabolic regulation. Finally the biosynthetic pathway of the phenylalanine-derived fruit volatiles phenylethanol and phenylacetaldehyde was elucidated via a combination of metabolic profiling of natural variation, stable isotope tracer experiments and reverse genetic experimentation.
The Lyman-𝛼 (Ly𝛼) line commonly assists in the detection of high-redshift galaxies, the so-called Lyman-alpha emitters (LAEs). LAEs are useful tools to study the baryonic matter distribution of the high-redshift universe. Exploring their spatial distribution not only reveals the large-scale structure of the universe at early epochs, but it also provides an insight into the early formation and evolution of the galaxies we observe today. Because dark matter halos (DMHs) serve as sites of galaxy formation, the LAE distribution also traces that of the underlying dark matter. However, the details of this relation and their co-evolution over time remain unclear. Moreover, theoretical studies predict that the spatial distribution of LAEs also impacts their own circumgalactic medium (CGM) by influencing their extended Ly𝛼 gaseous halos (LAHs), whose origin is still under investigation. In this thesis, I make several contributions to improve the knowledge on these fields using samples of LAEs observed with the Multi Unit Spectroscopic Explorer (MUSE) at redshifts of 3 < 𝑧 < 6.