Refine
Year of publication
Document Type
- Doctoral Thesis (85) (remove)
Language
- English (51)
- German (33)
- Multiple languages (1)
Is part of the Bibliography
- no (85) (remove)
Keywords
- Adipositas (3)
- Klimawandel (3)
- climate change (3)
- Kinder (2)
- Kontext (2)
- Mars (2)
- Nanoparticles (2)
- Nanopartikel (2)
- Spektroskopie (2)
- Transkriptionsfaktoren (2)
- children (2)
- education (2)
- inflammatory bowel disease (2)
- metabolism (2)
- obesity (2)
- sensor (2)
- spectroscopy (2)
- transcription factors (2)
- ATP (1)
- Absorptionseigenschaften (1)
- Adana Basin (1)
- Adana Becken (1)
- Africa (1)
- Afrika (1)
- Agency theory (1)
- Agency-Theorie (1)
- Aggression (1)
- Aktinzytoskelett (1)
- Aktive Arbeitsmarktpolitik (1)
- Aktuatoren (1)
- Allgemeine Relativitätstheorie (1)
- Alliance Capability (1)
- Allianzfähigkeit (1)
- Allianzkompetenz (1)
- Amyloid peptide (1)
- Anaphora (1)
- Anfragepaare (1)
- Anomalien (1)
- Anorexia nervosa (1)
- Anoxie (1)
- Anpassung (1)
- Apollo (1)
- Apyrase (1)
- Arbeitssuchverhalten (1)
- ArcObjects (1)
- Aspect-Oriented Programming (1)
- Aspektorientierte Programmierung (1)
- Ausführungsgeschichte (1)
- Automatisierung (1)
- Azobenzolhaltige Polymerfilme (1)
- Bayesian networks (1)
- Bayessche Netze (1)
- Bewältigungsstrategien (1)
- Bildanalyse (1)
- Bildung (1)
- Binding Theory (1)
- Biosignaturen (1)
- Blickbewegungen (1)
- Blickbewegungen beim Lesen (1)
- Brachionus (1)
- Breitband (1)
- Brownification (1)
- Bürgerdienste (1)
- Bürgerschaftliches Engagement (1)
- CAP (1)
- CSCW (1)
- Caco-2 (1)
- Capabilities based View (1)
- Capsule (1)
- Carbide (1)
- Carbides (1)
- Carbon Cycling (1)
- Carbon cycling (1)
- Carbonate (1)
- Carbonates (1)
- Cavity Ring-Down (1)
- Cellulose (1)
- Centering Theory (1)
- Charnockit (1)
- Chile (1)
- Chlamydomonas (1)
- Chloroplast (1)
- Chromatin-Immunopräzipitation (1)
- Claudin-4 (1)
- Cloud Computing (1)
- Cloud computing (1)
- Cobalt (1)
- Colitis ulcerosa (1)
- Common Sense Model of Illness Representation (1)
- Composites (1)
- Computationale Modellierung (1)
- Coping (1)
- Core-Collapse Supernovae (1)
- Crohn's disease (1)
- DDR (1)
- Data Privacy (1)
- Datenbank (1)
- Datenschutz (1)
- Deichbruch (1)
- Depression (1)
- Desensibilisierung (1)
- Design Thinking (1)
- Diagenese (1)
- Diagenesis (1)
- Digitale Whiteboards (1)
- Dionysos (1)
- Disambiguierung (1)
- Diskursgegebenheit (1)
- Dysarthrie (1)
- E. coli (1)
- Effizienzanalyse (1)
- Ehrenamt (1)
- Eliassen Palm Flux (1)
- Eliassen-Palm-Fluss (1)
- Eltern (1)
- Energiehaushalt (1)
- Ernährung (1)
- Erosion (1)
- Erziehung (1)
- Erziehungsheim (1)
- Fasern (1)
- Fehlende Daten (1)
- Fehlerbeseitigung (1)
- Feldflussfraktionierung (1)
- Field Flow Fractionation (1)
- Flavonoid (1)
- Flavonoid-Metabolismus (1)
- Flood (1)
- Fluoreszenz (1)
- Fläming (1)
- Formyl-Peptid Rezeptor 2 (1)
- Freiwilligenmanagement (1)
- Freizeit (1)
- Führungspraxis (1)
- GDR (1)
- GIS (1)
- Galaxien (1)
- Gas Sorption (1)
- Gassensorik (1)
- Gedankenschweifen (1)
- Gedankenverlorenes Lesen (1)
- Gefährdungskarten (1)
- General Relativity (1)
- Geoinformation (1)
- Geomorphologie (1)
- German Greens (1)
- German history (1)
- German history of sovereignty (12th and 13th century) (1)
- German reunification (1)
- Geschäftsprozessmanagement (1)
- Gießfolien (1)
- Gitterdynamik (1)
- Globaler Wandel (1)
- Gold Cluster (1)
- Gravitational Waves (1)
- Gravitationswellen (1)
- Grundwasser (1)
- Grüne (1)
- HCI (1)
- Habitus (1)
- Halo (1)
- Hebung des Plateaus (1)
- Hochgeschwindigkeitswolken (1)
- Hochwasser (1)
- Holzprodukte (1)
- IRRAS (1)
- In-situ Rasterkraftmikroskopie (1)
- Information (1)
- Informationstechnik (1)
- Informationsvorhaltung (1)
- Internet applications (1)
- Internetanwendungen (1)
- Inverse Probability Weighting (1)
- Ionic Liquid (1)
- Ivy (1)
- Java Security Framework (1)
- Jugend (1)
- Jugendliche (1)
- Kartoffel (1)
- Kern-Kollaps-Supernovae (1)
- Klassifikator (1)
- Klassifizierung (1)
- Kleintriebe (1)
- Koalition (1)
- Kohlenstoffspeicherung (1)
- Kommunale Verwaltung (1)
- Kommunikation (1)
- Kompetenzmanagement (1)
- Komposite (1)
- Konfliktgeschichte (1)
- Konjugierten polyelektrolyt (1)
- Konsumorietirte Steuerreform (1)
- Koreferenz (1)
- Krankheitsbewältigung (1)
- Land (1)
- Landepositionen (1)
- Landnutzung (1)
- Landwirtschaft (1)
- Langmuir monolayers (1)
- Latin American literature (1)
- Lebensqualität (1)
- Leistungsfähigkeit (1)
- Levels-of-inattention Hypothese (1)
- Lipide (1)
- Mars Express (1)
- Mathematics Tasks (1)
- Mathematik (1)
- Mathematikaufgaben (1)
- Mediengewalt (1)
- Meereis (1)
- Mehrschichtsysteme (1)
- Mensch-Computer-Interaktion (1)
- Merkmale (1)
- Metal-organic framework (1)
- Metall/Graphen/Polymer Grenzfläch (1)
- Methanogene Archaeen (1)
- Microalgae (1)
- Microemulsion (1)
- Mikroalgen (1)
- Mikroemulsion (1)
- Mikrokapsel (1)
- Mikropolitik (1)
- Mineralverwitterungsreaktionen (1)
- Miocene (1)
- Miozän (1)
- Modell der Bayesianischen Sakkadenplanung (1)
- Modellierung (1)
- Modelllernen (1)
- Mongolei (1)
- Mongolia (1)
- Monoschicht (1)
- Morbus Crohn (1)
- Multilayers (1)
- Myofibroblasten (1)
- Mythos (1)
- Nachmittagsbetreuung (1)
- Nahinfrarot (NIR) (1)
- Nanostruktur (1)
- Narziss (1)
- Netzwerke (1)
- New Public Management (1)
- Nukleosidase (1)
- Nährstoffe (1)
- Oberflächengitter (1)
- Obesity (1)
- Objektive Hermeneutik (1)
- On.Line Monitoring (1)
- Opto-mechanische Spannungen (1)
- Organgröße (1)
- Organisationstheorie (1)
- Owner-Retained Access Control (ORAC) (1)
- PISA (1)
- PSP (1)
- PSP-P (1)
- PSP-RS (1)
- Parasiten (1)
- Parasites (1)
- Partizipation (1)
- Pathogenantwort (1)
- Patientenschulung (1)
- Peptide (1)
- Performance (1)
- Perowskit (1)
- Pflanzenwachstum (1)
- Pflanzenzellen (1)
- Phospholipid (1)
- Photon density waves (1)
- Photonendichtewellen (1)
- Photosynthese (1)
- Physik (1)
- Pinus sylvestris (1)
- Plastome-evolution (1)
- Plastomevolution (1)
- Polder (1)
- Policy Languages (1)
- Policy Sprachen (1)
- Polyadenylierung (1)
- Polyelectrolyte (1)
- Polyelektrolyt (1)
- Prevalence (1)
- Primärproduktion (1)
- Probabilistische Modelle (1)
- Probiotika (1)
- Process Mining (1)
- Progredienzangst (1)
- Project management (1)
- Projektmanagement (1)
- Pronomen (1)
- Pronouns (1)
- Propensity Score Matching (1)
- Proteine (1)
- Proteom (1)
- Protest Parties (1)
- Protestparteien (1)
- Prävalenz (1)
- Psycholinguistik (1)
- QTL (1)
- Qualitätsmanagement (1)
- Quantum Dots (1)
- Quercetin (1)
- Quercus (1)
- RDF (1)
- RNA-seq (1)
- Raman Spektroskopie (1)
- Raman spectroscopy (1)
- Resource based View (1)
- Responsive Polymere (1)
- Richardson Syndrom (1)
- Richardson Syndrome (1)
- Risiko- und Vulnerabilitätsfaktoren (1)
- Risk and Vulnerability Factors (1)
- SJL (1)
- SME (1)
- SPARQL (1)
- STATT Partei (1)
- STATT Party (1)
- SWIM (1)
- Saprolit (1)
- Sardinia (1)
- Sardinien (1)
- Scalability (1)
- Schill (1)
- Schule (1)
- Sedimentenabfolge (1)
- Sedimentologie (1)
- Sedimentology (1)
- Selbstmanagement (1)
- Semantische Analyse (1)
- Semiklassik (1)
- Sensor (1)
- Sexual Aggression (1)
- Sexuelle Aggression (1)
- Shrub encroachment (1)
- Siberian permafrost (1)
- Skalierbarkeit (1)
- Softwareentwicklung (1)
- Softwareentwicklungsprozesse (1)
- Softwaretest (1)
- Sorption (1)
- Sri Lanka (1)
- Steuer (1)
- Steuerreform (1)
- Steuersystem (1)
- Stoffwechsel (1)
- Strategic Alliances (1)
- Strategic Management (1)
- Strategische Allianzen (1)
- Strategisches Management (1)
- Stress (1)
- Streuamplitude (1)
- Streutheorie (1)
- Stärke (1)
- Subsidenzgeschichte (1)
- Sumatra Störung (1)
- Sumatra fault (1)
- Süd-Türkei (1)
- Tarutung (1)
- Tbc1d1 (1)
- Test-getriebene Fehlernavigation (1)
- Tests (1)
- Tight Junction (1)
- Transaktivierungs-Experimente (1)
- Transforming Growth Factor beta (1)
- Transitionmetals (1)
- Transkriptomanalyse (1)
- Turkey (1)
- Türkei (1)
- Unsicherheitsanalyse (1)
- VMP1 (1)
- Vernetzte Daten (1)
- Verteiltes Arbeiten (1)
- Verwitterungsfeedback (1)
- Videoanalyse (1)
- Videometadaten (1)
- Videospiele (1)
- Vorhersage (1)
- Waldwachstumsmodell 4C (1)
- Wasserqualität (1)
- Wellenausbreitung (1)
- Wende (1)
- Wissen (1)
- Wortgrenzen (1)
- Zellform (1)
- Zelltyp-spezifisch (1)
- Zellulose (1)
- Zellulärmaterialien (1)
- Zinc (1)
- Zivilgesellschaft (1)
- actin cytoskeleton machine (1)
- active labor market policies (1)
- actuating materials (1)
- adapation (1)
- adaptation (1)
- adolescents (1)
- afternoon care (1)
- aggression (1)
- agriculture (1)
- analysis of efficiency (1)
- anaphora (1)
- anomalies (1)
- anorexia nervosa (1)
- anoxia (1)
- anxiety (1)
- apyrase (1)
- arbuscular mycorrhizal symbiosis (1)
- arbuskuläre Mykorrhiza-Symbiose (1)
- architectured materials (1)
- assistive Technologien (1)
- assistive technologies (1)
- attenuation tomography (1)
- automation (1)
- autophagy (1)
- azobenzene polymer films (1)
- back-in-time (1)
- biodiversity (1)
- biosignatures (1)
- broadband (1)
- brownification (1)
- business process management (1)
- carbon flow (1)
- carbon sequestration (1)
- casted-films (1)
- cavity ring-down (1)
- cell morphogenesis (1)
- cell shape (1)
- cell type-specific (1)
- cells epidermis (1)
- cellular materials (1)
- changeability (1)
- charnockite (1)
- chemical weathering (1)
- chemische Verwitterung (1)
- chlamydomonas (1)
- chromatin immunoprecipitation (1)
- chronisch entzündliche Darmerkrankungen (1)
- chronisch-entzündliche Darmerkrankungen (1)
- citizen services (1)
- civic culture (1)
- classification (1)
- classifier (1)
- claudin-4 (1)
- coalition (1)
- cobalt (1)
- cognitive functions (1)
- common sense model of illness representation (1)
- communication (1)
- computational modeling (1)
- concepts of illness (1)
- conflict (1)
- conjugated polyelectrolyte (1)
- context (1)
- context awareness (1)
- coping (1)
- coreference (1)
- countryside (1)
- critical zone (1)
- crop modeling (1)
- cscw (1)
- cytokinesis (1)
- database (1)
- debugging (1)
- depression (1)
- desensitization (1)
- design thinking (1)
- deutsche Geschichte (1)
- deutsche Herrschaftsbildung (12./13. Jh.) (1)
- diet (1)
- diffuse Belastung (1)
- diffuse pollution (1)
- digital whiteboard (1)
- dike breach (1)
- directed projects (1)
- discourse-givenness (1)
- disease management (1)
- dysarthria (1)
- dysarthric features (1)
- empirical labor market studies (1)
- empirical studies (1)
- empirische Arbeitsmarktforschung (1)
- empirische Studien (1)
- energy budget (1)
- erosion (1)
- extracellular matrix (1)
- extrazelluläre Matrix (1)
- eye movements (1)
- eye movements during reading (1)
- fear of progression (1)
- fibres (1)
- films (1)
- fiscal policy (1)
- flavonoid (1)
- flavonoid biosynthesis (1)
- fluorescence (1)
- forest growth model 4C (1)
- forestry (1)
- formyl peptide receptor 2 (1)
- galaxies (1)
- gas sensing (1)
- gas sorption (1)
- gelenkte Projekte (1)
- geoinformation (1)
- geological processes (1)
- geologische Prozesse (1)
- geomorphology (1)
- global change (1)
- ground water (1)
- halo (1)
- hazard maps (1)
- high-velocity-clouds (1)
- hydrogel (1)
- illness representations (1)
- in-situ atomic force microscopy (1)
- indigenous chronic (1)
- information (1)
- information technology (1)
- integrated personal income tax (1)
- inverse probability weighting (1)
- ionic liquid (1)
- job search behavior (1)
- kinetic modeling (1)
- kinetische Modellierung (1)
- knowledge (1)
- kognitive Funktionen (1)
- kritische Zone (1)
- land use (1)
- landing positions (1)
- lattice dynamics (1)
- leadership (1)
- learning networks plant (1)
- leisure time (1)
- levels-of-inattention hypothesis (1)
- linked data (1)
- local government (1)
- loss-of-function mutation (1)
- loss-of-function-Mutation (1)
- mathematics (1)
- media violence (1)
- metabolic costs (1)
- metabolic networks (1)
- metabolische Kosten (1)
- metabolische Netzwerke (1)
- metal-organic framework (1)
- metal/polymer interfaces (1)
- methanogenic archaea (1)
- miRNA (1)
- miRNAs (1)
- micro politics (1)
- mind wandering (1)
- mindless reading (1)
- mineral weathering reactions (1)
- missing data (1)
- model of Bayesian saccade planning (1)
- model-driven engineering (1)
- modelgetriebene Entwicklung (1)
- modeling (1)
- modelling (1)
- myofibroblast (1)
- myth (1)
- nanostructure (1)
- near-infrared (NIR) (1)
- new public management (1)
- nonprofit (1)
- nucleosidase (1)
- nutrients (1)
- online assistance (1)
- opal (1)
- optische Anregung (1)
- opto-mechanical stresses (1)
- organ size (1)
- organizational theory (1)
- overgrazing (1)
- parents (1)
- participation (1)
- pathogen response (1)
- patient education (1)
- pavement cells image analysis (1)
- perovskite (1)
- photoexcitation (1)
- photosynthesis (1)
- physics (1)
- physiologische Verfahren (1)
- plateau uplift (1)
- polder (1)
- political utopia (1)
- polyadenylation (1)
- potato (1)
- prediction (1)
- prefetching (1)
- primary production (1)
- probabilistic models (1)
- probiotics (1)
- process mining (1)
- propensity score matching (1)
- protein (1)
- proteins (1)
- proteomics (1)
- psycholinguistics (1)
- psychophysiological measures (1)
- qualitative pathway interpretation (1)
- quality of life (1)
- qualitymanagement (1)
- quercetin (1)
- query matching (1)
- reconfigurable matter (1)
- remote collaboration (1)
- reptiles (1)
- responsive (1)
- responsive polymer (1)
- saprolite (1)
- scattering amplitude (1)
- scattering theory (1)
- school (1)
- sea ice (1)
- sedimentary record (1)
- seismische Geschwindigkeiten (1)
- self-management (1)
- semantic analysis (1)
- semiclassics (1)
- sibirischen Permafrost (1)
- sign language (1)
- software development (1)
- software development processes (1)
- southern Turkey (1)
- stable isotope tracing (1)
- starch (1)
- status quo and reform model (1)
- stochastic Petri nets (1)
- stochastische Petri Netze (1)
- stoichiometric modeling (1)
- stress (1)
- stöchiometrische Modellierung (1)
- subjektive Krankheitskonzepte (1)
- subsidence history (1)
- sucrose (1)
- surface relief grating (1)
- swelling (1)
- tax system (1)
- temperature (1)
- test-driven fault navigation (1)
- testing (1)
- tf-idf (1)
- the turnaround (1)
- thermoplastic (1)
- thermoplastisch (1)
- tight junction (1)
- transactivation assay (1)
- transcriptome (1)
- transcriptome analysis (1)
- transformational (1)
- transforming growth factor beta (1)
- ubiquity of new knowledge (1)
- ulcerative colitis (1)
- ultrafast X-ray diffraction (1)
- ultraschnelle Röntgendiffraktion (1)
- uncertainty analysis (1)
- unipolar affective disorders (1)
- unipolare affektive Störungen (1)
- user interfaces (1)
- velocity structure (1)
- video analysis (1)
- video games (1)
- video metadata (1)
- violence of latin letter (1)
- volunteer management (1)
- volunteering (1)
- water balance (1)
- water quality (1)
- wave propagation (1)
- weathering feedback (1)
- wood products (1)
- word boundaries (1)
- word sense disambiguation (1)
- word skipping (1)
- worries and concerns (1)
- youth (1)
- zinc (1)
- zooplankton (1)
- Änderbarkeit (1)
- Ängste und Sorgen (1)
- Übergangsmetalle (1)
- Überspringen von Wörtern (1)
- Čechov (1)
Institute
- Institut für Biochemie und Biologie (15)
- Institut für Chemie (9)
- Institut für Physik und Astronomie (8)
- Department Psychologie (7)
- Hasso-Plattner-Institut für Digital Engineering gGmbH (7)
- Institut für Umweltwissenschaften und Geographie (7)
- Institut für Geowissenschaften (5)
- Wirtschaftswissenschaften (5)
- Extern (4)
- Sozialwissenschaften (4)
The objective and motivation behind this research is to provide applications with easy-to-use interfaces to communities of deaf and functionally illiterate users, which enables them to work without any human assistance. Although recent years have witnessed technological advancements, the availability of technology does not ensure accessibility to information and communication technologies (ICT). Extensive use of text from menus to document contents means that deaf or functionally illiterate can not access services implemented on most computer software. Consequently, most existing computer applications pose an accessibility barrier to those who are unable to read fluently. Online technologies intended for such groups should be developed in continuous partnership with primary users and include a thorough investigation into their limitations, requirements and usability barriers. In this research, I investigated existing tools in voice, web and other multimedia technologies to identify learning gaps and explored ways to enhance the information literacy for deaf and functionally illiterate users. I worked on the development of user-centered interfaces to increase the capabilities of deaf and low literacy users by enhancing lexical resources and by evaluating several multimedia interfaces for them. The interface of the platform-independent Italian Sign Language (LIS) Dictionary has been developed to enhance the lexical resources for deaf users. The Sign Language Dictionary accepts Italian lemmas as input and provides their representation in the Italian Sign Language as output. The Sign Language dictionary has 3082 signs as set of Avatar animations in which each sign is linked to a corresponding Italian lemma. I integrated the LIS lexical resources with MultiWordNet (MWN) database to form the first LIS MultiWordNet(LMWN). LMWN contains information about lexical relations between words, semantic relations between lexical concepts (synsets), correspondences between Italian and sign language lexical concepts and semantic fields (domains). The approach enhances the deaf users’ understanding of written Italian language and shows that a relatively small set of lexicon can cover a significant portion of MWN. Integration of LIS signs with MWN made it useful tool for computational linguistics and natural language processing. The rule-based translation process from written Italian text to LIS has been transformed into service-oriented system. The translation process is composed of various modules including parser, semantic interpreter, generator, and spatial allocation planner. This translation procedure has been implemented in the Java Application Building Center (jABC), which is a framework for extreme model driven design (XMDD). The XMDD approach focuses on bringing software development closer to conceptual design, so that the functionality of a software solution could be understood by someone who is unfamiliar with programming concepts. The transformation addresses the heterogeneity challenge and enhances the re-usability of the system. For enhancing the e-participation of functionally illiterate users, two detailed studies were conducted in the Republic of Rwanda. In the first study, the traditional (textual) interface was compared with the virtual character-based interactive interface. The study helped to identify usability barriers and users evaluated these interfaces according to three fundamental areas of usability, i.e. effectiveness, efficiency and satisfaction. In another study, we developed four different interfaces to analyze the usability and effects of online assistance (consistent help) for functionally illiterate users and compared different help modes including textual, vocal and virtual character on the performance of semi-literate users. In our newly designed interfaces the instructions were automatically translated in Swahili language. All the interfaces were evaluated on the basis of task accomplishment, time consumption, System Usability Scale (SUS) rating and number of times the help was acquired. The results show that the performance of semi-literate users improved significantly when using the online assistance. The dissertation thus introduces a new development approach in which virtual characters are used as additional support for barely literate or naturally challenged users. Such components enhanced the application utility by offering a variety of services like translating contents in local language, providing additional vocal information, and performing automatic translation from text to sign language. Obviously, there is no such thing as one design solution that fits for all in the underlying domain. Context sensitivity, literacy and mental abilities are key factors on which I concentrated and the results emphasize that computer interfaces must be based on a thoughtful definition of target groups, purposes and objectives.
Mathematical modeling of biological systems is a powerful tool to systematically investigate the functions of biological processes and their relationship with the environment. To obtain accurate and biologically interpretable predictions, a modeling framework has to be devised whose assumptions best approximate the examined scenario and which copes with the trade-off of complexity of the underlying mathematical description: with attention to detail or high coverage. Correspondingly, the system can be examined in detail on a smaller scale or in a simplified manner on a larger scale. In this thesis, the role of photosynthesis and its related biochemical processes in the context of plant metabolism was dissected by employing modeling approaches ranging from kinetic to stoichiometric models. The Calvin-Benson cycle, as primary pathway of carbon fixation in C3 plants, is the initial step for producing starch and sucrose, necessary for plant growth. Based on an integrative analysis for model ranking applied on the largest compendium of (kinetic) models for the Calvin-Benson cycle, those suitable for development of metabolic engineering strategies were identified. Driven by the question why starch rather than sucrose is the predominant transitory carbon storage in higher plants, the metabolic costs for their synthesis were examined. The incorporation of the maintenance costs for the involved enzymes provided a model-based support for the preference of starch as transitory carbon storage, by only exploiting the stoichiometry of synthesis pathways. Many photosynthetic organisms have to cope with processes which compete with carbon fixation, such as photorespiration whose impact on plant metabolism is still controversial. A systematic model-oriented review provided a detailed assessment for the role of this pathway in inhibiting the rate of carbon fixation, bridging carbon and nitrogen metabolism, shaping the C1 metabolism, and influencing redox signal transduction. The demand of understanding photosynthesis in its metabolic context calls for the examination of the related processes of the primary carbon metabolism. To this end, the Arabidopsis core model was assembled via a bottom-up approach. This large-scale model can be used to simulate photoautotrophic biomass production, as an indicator for plant growth, under so-called optimal, carbon-limiting and nitrogen-limiting growth conditions. Finally, the introduced model was employed to investigate the effects of the environment, in particular, nitrogen, carbon and energy sources, on the metabolic behavior. This resulted in a purely stoichiometry-based explanation for the experimental evidence for preferred simultaneous acquisition of nitrogen in both forms, as nitrate and ammonium, for optimal growth in various plant species. The findings presented in this thesis provide new insights into plant system's behavior, further support existing opinions for which mounting experimental evidences arise, and posit novel hypotheses for further directed large-scale experiments.
Planetary research is often user-based and requires considerable skill, time, and effort. Unfortunately, self-defined boundary conditions, definitions, and rules are often not documented or not easy to comprehend due to the complexity of research. This makes a comparison to other studies, or an extension of the already existing research, complicated. Comparisons are often distorted, because results rely on different, not well defined, or even unknown boundary conditions. The purpose of this research is to develop a standardized analysis method for planetary surfaces, which is adaptable to several research topics. The method provides a consistent quality of results. This also includes achieving reliable and comparable results and reducing the time and effort of conducting such studies. A standardized analysis method is provided by automated analysis tools that focus on statistical parameters. Specific key parameters and boundary conditions are defined for the tool application. The analysis relies on a database in which all key parameters are stored. These databases can be easily updated and adapted to various research questions. This increases the flexibility, reproducibility, and comparability of the research. However, the quality of the database and reliability of definitions directly influence the results. To ensure a high quality of results, the rules and definitions need to be well defined and based on previously conducted case studies. The tools then produce parameters, which are obtained by defined geostatistical techniques (measurements, calculations, classifications). The idea of an automated statistical analysis is tested to proof benefits but also potential problems of this method. In this study, I adapt automated tools for floor-fractured craters (FFCs) on Mars. These impact craters show a variety of surface features, occurring in different Martian environments, and having different fracturing origins. They provide a complex morphological and geological field of application. 433 FFCs are classified by the analysis tools due to their fracturing process. Spatial data, environmental context, and crater interior data are analyzed to distinguish between the processes involved in floor fracturing. Related geologic processes, such as glacial and fluvial activity, are too similar to be separately classified by the automated tools. Glacial and fluvial fracturing processes are merged together for the classification. The automated tools provide probability values for each origin model. To guarantee the quality and reliability of the results, classification tools need to achieve an origin probability above 50 %. This analysis method shows that 15 % of the FFCs are fractured by intrusive volcanism, 20 % by tectonic activity, and 43 % by water & ice related processes. In total, 75 % of the FFCs are classified to an origin type. This can be explained by a combination of origin models, superposition or erosion of key parameters, or an unknown fracturing model. Those features have to be manually analyzed in detail. Another possibility would be the improvement of key parameters and rules for the classification. This research shows that it is possible to conduct an automated statistical analysis of morphologic and geologic features based on analysis tools. Analysis tools provide additional information to the user and are therefore considered assistance systems.
Causes for slow weathering and erosion in the steep, warm, monsoon-subjected Highlands of Sri Lanka
(2018)
In the Highlands of Sri Lanka, erosion and chemical weathering rates are among the lowest for global mountain denudation. In this tropical humid setting, highly weathered deep saprolite profiles have developed from high-grade metamorphic charnockite during spheroidal weathering of the bedrock. The spheroidal weathering produces rounded corestones and spalled rindlets at the rock-saprolite interface. I used detailed textural, mineralogical, chemical, and electron-microscopic (SEM, FIB, TEM) analyses to identify the factors limiting the rate of weathering front advance in the profile, the sequence of weathering reactions, and the underlying mechanisms. The first mineral attacked by weathering was found to be pyroxene initiated by in situ Fe oxidation, followed by in situ biotite oxidation. Bulk dissolution of the primary minerals is best described with a dissolution – re-precipitation process, as no chemical gradients towards the mineral surface and sharp structural boundaries are observed at the nm scale. Only the local oxidation in pyroxene and biotite is better described with an ion by ion process. The first secondary phases are oxides and amorphous precipitates from which secondary minerals (mainly smectite and kaolinite) form. Only for biotite direct solid state transformation to kaolinite is likely. The initial oxidation of pyroxene and biotite takes place in locally restricted areas and is relatively fast: log J = -11 molmin/(m2 s). However, calculated corestone-scale mineral oxidation rates are comparable to corestone-scale mineral dissolution rates: log R = -13 molpx/(m2 s) and log R = -15 molbt/(m2 s). The oxidation reaction results in a volume increase. Volumetric calculations suggest that this observed oxidation leads to the generation of porosity due to the formation of micro-fractures in the minerals and the bedrock allowing for fluid transport and subsequent dissolution of plagioclase. At the scale of the corestone, this fracture reaction is responsible for the larger fractures that lead to spheroidal weathering and to the formation of rindlets. Since these fractures have their origin from the initial oxidational induced volume increase, oxidation is the rate limiting parameter for weathering to take place. The ensuing plagioclase weathering leads to formation of high secondary porosity in the corestone over a distance of only a few cm and eventually to the final disaggregation of bedrock to saprolite. As oxidation is the first weathering reaction, the supply of O2 is a rate-limiting factor for chemical weathering. Hence, the supply of O2 and its consumption at depth connects processes at the weathering front with erosion at the surface in a feedback mechanism. The strength of the feedback depends on the relative weight of advective versus diffusive transport of O2 through the weathering profile. The feedback will be stronger with dominating diffusive transport. The low weathering rate ultimately depends on the transport of O2 through the whole regolith, and on lithological factors such as low bedrock porosity and the amount of Fe-bearing primary minerals. In this regard the low-porosity charnockite with its low content of Fe(II) bearing minerals impedes fast weathering reactions. Fresh weatherable surfaces are a pre-requisite for chemical weathering. However, in the case of the charnockite found in the Sri Lankan Highlands, the only process that generates these surfaces is the fracturing induced by oxidation. Tectonic quiescence in this region and low pre-anthropogenic erosion rate (attributed to a dense vegetation cover) minimize the rejuvenation of the thick and cohesive regolith column, and lowers weathering through the feedback with erosion.
Menschen mit chronisch entzündlichen Darmerkrankungen (CED) leiden unter vielfältigen körperlichen und psychosozialen Einschränkungen. Wie auch bei anderen chronischen Erkrankungen könnten Patientenschulungen ihr psychisches Befinden verbessern (z.B. De Ridder & Schreurs, 2001; Faller, Reusch & Meng, 2011a; Küver, Becker & Ludt, 2008; Schüssler, 1998; Warsi, Wang, LaValley, Avorn & Solomon, 2004). Für CED liegen jedoch nur wenige Schulungsevaluationen vor (z.B. Bregenzer et al., 2005; Mussell, Böcker, Nagel, Olbrich & Singer, 2003; Oxelmark, Magnusson, Löfberg & Hillerås, 2007), deren Aussagekraft i.d.R. durch methodische Mängel eingeschränkt ist. Daher ist die Bedeutung von Schulungsprogrammen für CED-Betroffene weiterhin offen. Überdies gibt es für den deutschen Sprachraum noch keine Schulung, die zu psychischen Verbesserungen führt. Aus diesem Grunde wurde ein 1,5-tägiges Wochenend-Seminar mit medizinischen und psychologischen Inhalten konzeptionalisiert, manualisiert und in der vorliegenden Studie evaluiert.
Zur summativen Evaluation nahmen 181 ambulante CED-Patienten an einer prospektiven, multizentrischen, randomisierten, kontrollierten Studie mit vier Messzeitpunkten teil: vor (T1), zwei Wochen (T2) und drei Monate (T3) nach dem Seminar. Zur 12-Monatskatamnese (T4EG) wurde die Stabilität der Effekte in der Experimentalgruppe (EG; n = 86) überprüft. Die Wartekontrollgruppe (n = 95) erhielt zunächst die Standardbehandlung, also keine Patientenschulung, und konnte an dieser nach der dritten Datenerhebung ebenfalls teilnehmen. Kovarianzanalysen (ANCOVAs) mit Kontrolle für die jeweilige Ausgangslage wurden durchgeführt. Weitere Analysen legten eine Adjustierung für die Krankheitsaktivität zu T1 nahe, weshalb diese als zusätzliche Kovariate in die ANCOVAs aufgenommen wurde. Krankheitsbezogene Ängste und Sorgen (PS-CEDE Gesamtwert zu T3; Krebs, Kachel & Faller, 1998) fungierten als primärer Zielparameter. Zu den sekundären Zielkriterien gehörten Progredienzangst und Angstbewältigung (PA-F-KF und PA-F; Mehnert, Herschbach, Berg, Henrich & Koch, 2006 bzw. Dankert et al., 2003; Herschbach et al., 2005) sowie die Gesundheitskompetenzen Positive Grundhaltung, Aktive Lebensgestaltung und Erwerb von Fertigkeiten und Handlungsstrategien (heiQ; Osborne, Elsworth & Whitfield, 2007; Schuler et al., 2013). Weitere sekundäre Zielparameter waren gesundheitsbezogene Lebensqualität (SF-12; Bullinger & Kirchberger, 1998), Symptome einer Angststörung oder Depression (PHQ-4; Kroenke, Spitzer, Williams & Löwe, 2009; Löwe et al., 2010), Wissen, der Umgang mit der CED bzw. von ihr ausgelösten negativen Gefühlen sowie die Zufriedenheit der Teilnehmenden mit dem Seminar. Von Interesse war außerdem, ob Geschlecht, Alter, Art, Dauer oder Aktivität der Erkrankung vor der Schulung einen Einfluss auf die genannten Variablen hatten und ob für sie differentielle Wirksamkeitseffekte bestanden. Darüber hinaus wurden krankheitsbezogene Ängste und Sorgen von ungeschulten Studienteilnehmern untersucht.
Zwei Wochen und drei Monate nach der Schulung ließen sich im Vergleich von Experimental- und Kontrollgruppe signifikante, mittlere bis große Effekte auf krankheitsbezogene Ängste und Sorgen, Progredienzangst und deren Bewältigung sowie eine Positive Grundhaltung der CED gegenüber erzielen (stets p ≤ .001). Außerdem kam es zu beiden Messzeitpunkten zu signifikanten, großen Interventionseffekten auf den Erwerb von Fertigkeiten und Handlungsstrategien im Umgang mit der Erkrankung, das Wissen um sie und den Umgang mit ihr (stets p < .001) sowie zu moderaten Effekten auf den Umgang mit CED-bedingten negativen Gefühlen (T2: p = .001; T3: p = .008). Alle beschriebenen Effekte waren auch nach zwölf Monaten noch stabil. Für Aktive Lebensgestaltung, gesundheitsbezogene Lebensqualität sowie Angst- und Depressionssymptomatik konnten keine Schulungseffekte nachgewiesen werden.
Die zusätzliche Kontrolle für die Krankheitsaktivität zu T1 führte zu keinen wesentlichen Änderungen in den Ergebnissen. Auch bei den Subgruppenanalysen hatte die Krankheitsaktivität keinen relevanten Einfluss auf die Wirksamkeit der Schulung. Gleiches gilt für Geschlecht, Alter, Art und Dauer der CED. Mit Ausnahme der Krankheitsaktivität deuteten dies bereits die zur Baseline durchgeführten t-Tests an, bei denen insgesamt nur sehr wenige signifikante, höchstens moderate Unterschiede zwischen den einzelnen Subgruppen auftraten.
Sowohl bei der formativen als auch der summativen Evaluation zeigte sich überdies die hohe Zufriedenheit der Teilnehmenden mit der Schulung. Neben der Akzeptanz konnte außerdem die Durchführbarkeit bestätigt werden. Die Auswertung der Ängste und Sorgen der Studienteilnehmenden lieferte zudem Hinweise für die Entwicklung und Modifikation von Interventionen für CED-Betroffene.
Es lässt sich festhalten, dass für die hier evaluierte Schulung für CED-Patienten ein Wirksamkeitsnachweis erbracht werden konnte und sie sehr positiv von den Teilnehmenden bewertet wurde. Sie führte sowohl kurz-, mittel- als auch langfristig zu substantiellen Verbesserungen in psychischer Belastung, Selbstmanagement-Fähigkeiten, der Bewältigung der Erkrankung sowie im Wissen und war gleichermaßen wirksam bei Betroffenen, die sich in Geschlecht, Alter, Art, Dauer oder Aktivität ihrer CED unterschieden.
For the first time the transcriptional reprogramming of distinct root cortex cells during the arbuscular mycorrhizal (AM) symbiosis was investigated by combining Laser Capture Mirodissection and Affymetrix GeneChip® Medicago genome array hybridization. The establishment of cryosections facilitated the isolation of high quality RNA in sufficient amounts from three different cortical cell types. The transcript profiles of arbuscule-containing cells (arb cells), non-arbuscule-containing cells (nac cells) of Rhizophagus irregularis inoculated Medicago truncatula roots and cortex cells of non-inoculated roots (cor) were successfully explored. The data gave new insights in the symbiosis-related cellular reorganization processes and indicated that already nac cells seem to be prepared for the upcoming fungal colonization. The mycorrhizal- and phosphate-dependent transcription of a GRAS TF family member (MtGras8) was detected in arb cells and mycorrhizal roots. MtGRAS shares a high sequence similarity to a GRAS TF suggested to be involved in the fungal colonization processes (MtRAM1). The function of MtGras8 was unraveled upon RNA interference- (RNAi-) mediated gene silencing. An AM symbiosis-dependent expression of a RNAi construct (MtPt4pro::gras8-RNAi) revealed a successful gene silencing of MtGras8 leading to a reduced arbuscule abundance and a higher proportion of deformed arbuscules in root with reduced transcript levels. Accordingly, MtGras8 might control the arbuscule development and life-time. The targeting of MtGras8 by the phosphate-dependent regulated miRNA5204* was discovered previously (Devers et al., 2011). Since miRNA5204* is known to be affected by phosphate, the posttranscriptional regulation might represent a link between phosphate signaling and arbuscule development. In this work, the posttranscriptional regulation was confirmed by mis-expression of miRNA5204* in M. truncatula roots. The miRNA-mediated gene silencing affects the MtGras8 transcript abundance only in the first two weeks of the AM symbiosis and the mis-expression lines seem to mimic the phenotype of MtGras8-RNAi lines. Additionally, MtGRAS8 seems to form heterodimers with NSP2 and RAM1, which are known to be key regulators of the fungal colonization process (Hirsch et al., 2009; Gobbato et al., 2012). These data indicate that MtGras8 and miRNA5204* are linked to the sym pathway and regulate the arbuscule development in phosphate-dependent manner.
Lakes are increasingly being recognized as an important component of the global carbon cycle, yet anthropogenic activities that alter their community structure may change the way they transport and process carbon. This research focuses on the relationship between carbon cycling and community structure of primary producers in small, shallow lakes, which are the most abundant lake type in the world, and furthermore subject to intense terrestrial-aquatic coupling due to their high perimeter:area ratio. Shifts between macrophyte and phytoplankton dominance are widespread and common in shallow lakes, with potentially large consequences to regional carbon cycling. I thus compared a lake with clear-water conditions and a submerged macrophyte community to a turbid, phytoplankton-dominated lake, describing differences in the availability, processing, and export of organic and inorganic carbon. I furthermore examined the effects of increasing terrestrial carbon inputs on internal carbon cycling processes. Pelagic diel (24-hour) oxygen curves and independent fluorometric approaches of individual primary producers together indicated that the presence of a submerged macrophyte community facilitated higher annual rates of gross primary production than could be supported in a phytoplankton-dominated lake at similar nutrient concentrations. A simple model constructed from the empirical data suggested that this difference between regime types could be common in moderately eutrophic lakes with mean depths under three to four meters, where benthic primary production is a potentially major contributor to the whole-lake primary production. It thus appears likely that a regime shift from macrophyte to phytoplankton dominance in shallow lakes would typically decrease the quantity of autochthonous organic carbon available to lake food webs. Sediment core analyses indicated that a regime shift from macrophyte to phytoplankton dominance was associated with a four-fold increase in carbon burial rates, signalling a major change in lake carbon cycling dynamics. Carbon mass balances suggested that increasing carbon burial rates were not due to an increase in primary production or allochthonous loading, but instead were due to a higher carbon burial efficiency (carbon burial / carbon deposition). This, in turn, was associated with diminished benthic mineralization rates and an increase in calcite precipitation, together resulting in lower surface carbon dioxide emissions. Finally, a period of unusually high precipitation led to rising water levels, resulting in a feedback loop linking increasing concentrations of dissolved organic carbon (DOC) to severely anoxic conditions in the phytoplankton-dominated system. High water levels and DOC concentrations diminished benthic primary production (via shading) and boosted pelagic respiration rates, diminishing the hypolimnetic oxygen supply. The resulting anoxia created redox conditions which led to a major release of nutrients, DOC, and iron from the sediments. This further transformed the lake metabolism, providing a prolonged summertime anoxia below a water depth of 1 m, and leading to the near-complete loss of fish and macroinvertebrates. Pelagic pH levels also decreased significantly, increasing surface carbon dioxide emissions by an order of magnitude compared to previous years. Altogether, this thesis adds an important body of knowledge to our understanding of the significance of the benthic zone to carbon cycling in shallow lakes. The contribution of the benthic zone towards whole-lake primary production was quantified, and was identified as an important but vulnerable site for primary production. Benthic mineralization rates were furthermore found to influence carbon burial and surface emission rates, and benthic primary productivity played an important role in determining hypolimnetic oxygen availability, thus controlling the internal sediment loading of nutrients and carbon. This thesis also uniquely demonstrates that the ecological community structure (i.e. stable regime) of a eutrophic, shallow lake can significantly influence carbon availability and processing. By changing carbon cycling pathways, regime shifts in shallow lakes may significantly alter the role of these ecosystems with respect to the global carbon cycle.
NutzerInnen von gewalthaltigen Medien geben einerseits oftmals zu, dass sie fiktionale, gewalthaltige Medien konsumieren, behaupten jedoch gleichzeitig, dass dies nicht ihr Verhalten außerhalb des Medienkontexts beeinflusst. Sie argumentieren, dass sie leicht zwischen Dingen, die im fiktionalen Kontext und Dingen, die in der Realität gelernt wurden, unterscheiden können. Im Kontrast zu diesen Aussagen zeigen Metanalysen Effektstärken im mittleren Bereich für den Zusammenhang zwischen Gewaltmedienkonsum und aggressivem Verhalten. Diese Ergebnisse können nur erklärt werden, wenn MediennutzerInnen gewalthaltige Lernerfahrungen auch außerhalb des Medienkontexts anwenden. Ein Prozess, der Lernerfahrungen innerhalb des Medienkontexts mit dem Verhalten in der realen Welt verknüpft, ist Desensibilisierung, die oftmals eine Reduktion des negativen Affektes gegenüber Gewalt definiert ist. Zur Untersuchung des Desensibilisierungsprozesses wurden vier Experimente durchgeführt. Die erste in dieser Arbeit untersuchte Hypothese war, dass je häufiger Personen Gewaltmedien konsumieren, desto weniger negativen Affekt zeigen sie gegenüber Bildern mit realer Gewalt. Jedoch wurde angenommen, dass diese Bewertung auf Darstellungen von realer Gewalt beschränkt ist und nicht bei Bildern ohne Gewaltbezug, die einen negativen Affekt auslösen, zu finden ist. Die zweite Hypothese bezog sich auf den Affekt während des Konsums von Mediengewalt. Hier wurde angenommen, dass besonders Personen, die Freude an Gewalt in den Medien empfinden weniger negativen Affekt gegenüber realen Gewaltdarstellungen zeigen. Die letzte Hypothese beschäftigte sich mit kognitiver Desensibilisierung und sagte vorher, dass Gewaltmedienkonsum zu einem Transfer von Reaktionen, die normalerweise gegenüber gewalthaltigen Reizen gezeigt werden, auf ursprünglich neutrale Reize führt. Das erste Experiment (N = 57) untersuchte, ob die habituelle Nutzung von gewalthaltigen Medien den selbstberichteten Affekt (Valenz und Aktivierung) gegenüber Darstellungen von realer Gewalt und nichtgewalthaltigen Darstellungen, die negativen Affekt auslösen, vorhersagt. Die habituelle Nutzung von gewalthaltigen Medien sagte weniger negative Valenz und weniger allgemeine Aktivierung gegenüber gewalthalten und nichtgewalthaltigen Bildern vorher. Das zweite Experiment (N = 103) untersuchte auch die Beziehung zwischen habituellem Gewaltmedienkonsum und den affektiven Reaktionen gegenüber Bildern realer Gewalt und negativen affektauslösenden Bildern. Als weiterer Prädiktor wurde der Affekt beim Betrachten von gewalthaltigen Medien hinzugefügt. Der Affekt gegenüber den Bildern wurde zusätzlich durch psychophysiologische Maße (Valenz: C: Supercilii; Aktivierung: Hautleitreaktion) erhoben. Wie zuvor sagte habitueller Gewaltmedienkonsum weniger selbstberichte Erregung und weniger negative Valenz für die gewalthaltigen und die negativen, gewalthaltfreien Bilder vorher. Die physiologischen Maßen replizierten dieses Ergebnis. Jedoch zeigte sich ein anderes Muster für den Affekt beim Konsum von Gewalt in den Medien. Personen, die Gewalt in den Medien stärker erfreut, zeigen eine Reduktion der Responsivität gegenüber Gewalt auf allen vier Maßen. Weiterhin war bei drei dieser vier Maße (selbstberichte Valenz, Aktivität des C. Supercilii und Hautleitreaktion) dieser Zusammenhang auf die gewalthaltigen Bilder beschränkt, mit keinem oder nur einem kleinen Effekt auf die negativen, aber nichtgewalthaltigen Bilder. Das dritte Experiment (N = 73) untersuchte den Affekt während die Teilnehmer ein Computerspiel spielten. Das Spiel wurde eigens für dieses Experiment programmiert, sodass einzelne Handlungen im Spiel mit der Aktivität des C. Supercilii, dem Indikator für negativen Affekt, in Bezug gesetzt werden konnten. Die Analyse des C. Supercilii zeigte, dass wiederholtes Durchführen von aggressiven Spielzügen zu einem Rückgang von negativen Affekt führte, der die aggressiven Spielhandlungen begleitete. Der negative Affekt während gewalthaltiger Spielzüge wiederum sagte die affektive Reaktion gegenüber Darstellungen von gewalthaltigen Bildern vorher, nicht jedoch gegenüber den negativen Bildern. Das vierte Experiment (N = 77) untersuchte kognitive Desensibilisierung, die die Entwicklung von Verknüpfungen zwischen neutralen und aggressiven Kognitionen beinhaltete. Die Teilnehmer spielten einen Ego-Shooter entweder auf einem Schiff- oder einem Stadtlevel. Die Beziehung zwischen den neutralen Konstrukten (Schiff/Stadt) und den aggressiven Kognitionen wurde mit einer lexikalischen Entscheidungsaufgabe gemessen. Das Spielen im Schiff-/Stadt-Level führte zu einer kürzen Reaktionszeit für aggressive Wörter, wenn sie einem Schiff- bzw. Stadtprime folgten. Dies zeigte, dass die im Spiel enthaltenen neutralen Konzepte mit aggressiven Knoten verknüpft werden. Die Ergebnisse dieser vier Experimente wurden diskutiert im Rahmen eines lerntheoretischen Ansatzes um Desensibilisierung zu konzeptualisieren.
Cloud computing is a model for enabling on-demand access to a shared pool of computing resources. With virtually limitless on-demand resources, a cloud environment enables the hosted Internet application to quickly cope when there is an increase in the workload. However, the overhead of provisioning resources exposes the Internet application to periods of under-provisioning and performance degradation. Moreover, the performance interference, due to the consolidation in the cloud environment, complicates the performance management of the Internet applications. In this dissertation, we propose two approaches to mitigate the impact of the resources provisioning overhead. The first approach employs control theory to scale resources vertically and cope fast with workload. This approach assumes that the provider has knowledge and control over the platform running in the virtual machines (VMs), which limits it to Platform as a Service (PaaS) and Software as a Service (SaaS) providers. The second approach is a customer-side one that deals with the horizontal scalability in an Infrastructure as a Service (IaaS) model. It addresses the trade-off problem between cost and performance with a multi-goal optimization solution. This approach finds the scale thresholds that achieve the highest performance with the lowest increase in the cost. Moreover, the second approach employs a proposed time series forecasting algorithm to scale the application proactively and avoid under-utilization periods. Furthermore, to mitigate the interference impact on the Internet application performance, we developed a system which finds and eliminates the VMs suffering from performance interference. The developed system is a light-weight solution which does not imply provider involvement. To evaluate our approaches and the designed algorithms at large-scale level, we developed a simulator called (ScaleSim). In the simulator, we implemented scalability components acting as the scalability components of Amazon EC2. The current scalability implementation in Amazon EC2 is used as a reference point for evaluating the improvement in the scalable application performance. ScaleSim is fed with realistic models of the RUBiS benchmark extracted from the real environment. The workload is generated from the access logs of the 1998 world cup website. The results show that optimizing the scalability thresholds and adopting proactive scalability can mitigate 88% of the resources provisioning overhead impact with only a 9% increase in the cost.