@phdthesis{Kehm2019, author = {Kehm, Richard}, title = {The impact of metabolic stress and aging on functionality and integrity of pancreatic islets and beta-cells}, doi = {10.25932/publishup-44109}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-441099}, school = {Universit{\"a}t Potsdam}, pages = {VI, 138}, year = {2019}, abstract = {The increasing age of worldwide population is a major contributor for the rising prevalence of major pathologies and disease, such as type 2 diabetes, mediated by massive insulin resistance and a decline in functional beta-cell mass, highly associated with an elevated incidence of obesity. Thus, the impact of aging under physiological conditions and in combination with diet-induced metabolic stress on characteristics of pancreatic islets and beta-cells, with the focus on functionality and structural integrity, were investigated in the present dissertation. Primarily induced by malnutrition due to chronic and excess intake of high caloric diets, containing large amounts of carbohydrates and fats, obesity followed by systemic inflammation and peripheral insulin resistance occurs over time, initiating metabolic stress conditions. Elevated insulin demands initiate an adaptive response by beta-cell mass expansion due to increased proliferation, but prolonged stress conditions drive beta-cell failure and loss. Aging has been also shown to affect beta-cell functionality and morphology, in particular by proliferative limitations. However, most studies in rodents were performed under beta-cell challenging conditions, such as high-fat diet interventions. Thus, in the first part of the thesis (publication I), a characterization of age-related alterations on pancreatic islets and beta-cells was performed by using plasma samples and pancreatic tissue sections of standard diet-fed C57BL/6J wild-type mice in several age groups (2.5, 5, 10, 15 and 21 months). Aging was accompanied by decreased but sustained islet proliferative potential as well as an induction of cellular senescence. This was associated with a progressive islet expansion to maintain normoglycemia throughout lifespan. Moreover, beta-cell function and mass were not impaired although the formation and accumulation of AGEs occurred, located predominantly in the islet vasculature, accompanied by an induction of oxidative and nitrosative (redox) stress. The nutritional behavior throughout human lifespan; however, is not restricted to a balanced diet. This emphasizes the significance to investigate malnutrition by the intake of high-energy diets, inducing metabolic stress conditions that synergistically with aging might amplify the detrimental effects on endocrine pancreas. Using diabetes-prone NZO mice aged 7 weeks, fed a dietary regimen of carbohydrate restriction for different periods (young mice - 11 weeks, middle-aged mice - 32 weeks) followed by a carbohydrate intervention for 3 weeks, offered the opportunity to distinguish the effects of diet-induced metabolic stress in different ages on the functionality and integrity of pancreatic islets and their beta-cells (publication II, manuscript). Interestingly, while young NZO mice exhibited massive hyperglycemia in response to diet-induced metabolic stress accompanied by beta-cell dysfunction and apoptosis, middle-aged animals revealed only moderate hyperglycemia by the maintenance of functional beta-cells. The loss of functional beta-cell mass in islets of young mice was associated with reduced expression of PDX1 transcription factor, increased endocrine AGE formation and related redox stress as well as TXNIP-dependent induction of the mitochondrial death pathway. Although the amounts of secreted insulin and the proliferative potential were comparable in both age groups, islets of middle-aged mice exhibited sustained PDX1 expression, almost regular insulin secretory function, increased capacity for cell cycle progression as well as maintained redox potential. The results of the present thesis indicate a loss of functional beta-cell mass in young diabetes-prone NZO mice, occurring by redox imbalance and induction of apoptotic signaling pathways. In contrast, aging under physiological conditions in C57BL/6J mice and in combination with diet-induced metabolic stress in NZO mice does not appear to have adverse effects on the functionality and structural integrity of pancreatic islets and beta-cells, associated with adaptive responses on changing metabolic demands. However, considering the detrimental effects of aging, it has to be assumed that the compensatory potential of mice might be exhausted at a later point of time, finally leading to a loss of functional beta-cell mass and the onset and progression of type 2 diabetes. The polygenic, diabetes-prone NZO mouse is a suitable model for the investigation of human obesity-associated type 2 diabetes. However, mice at advanced age attenuated the diabetic phenotype or do not respond to the dietary stimuli. This might be explained by the middle age of mice, corresponding to the human age of about 38-40 years, in which the compensatory mechanisms of pancreatic islets and beta cells towards metabolic stress conditions are presumably more active.}, language = {en} } @phdthesis{Grafe2019, author = {Grafe, Marianne Erika}, title = {Analysis of supramolecular assemblies of NE81, the first lamin protein in a non-metazoan organism}, doi = {10.25932/publishup-44180}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-441802}, school = {Universit{\"a}t Potsdam}, pages = {V, 94}, year = {2019}, abstract = {Lamine sind Proteine an der inneren Kernh{\"u}lle und bilden zusammen mit verbundenen Proteinen die nukle{\"a}re Lamina. Dieses Netzwerk sorgt f{\"u}r die Stabilit{\"a}t des Zellkerns und unterst{\"u}tzt die Organisation des Zell-Zytoskeletts. Zus{\"a}tzlich sind Lamine und ihre verbundenen Proteine in viele Prozesse wie Genregulation und Zelldifferenzierung involviert. Bis 2012 war der Stand der Forschung, dass nur bei mehrzelligen Organismen eine nukle{\"a}re Lamina zu finden ist. NE81 ist das erste lamin-{\"a}hnliche Protein, das in einem nicht-mehrzelligen Organismus (Dictyostelium discoideum) entdeckt wurde. Es hat viele Eigenschaften und Strukturmerkmale mit Laminen gemeinsam. Dazu z{\"a}hlt der dreiteilige Aufbau des Proteins, eine Phosphorylierungsstelle f{\"u}r ein Zellzyklus-abh{\"a}ngiges Enzym, ein Kernlokalisationssignal, wodurch das Protein in den Kern transportiert wird, sowie eine C-terminale Sequenz zur Verankerung des Proteins in der Kernh{\"u}lle. In dieser Arbeit wurden verschiedene Methoden zur vereinfachten Untersuchung von Laminstrukturen getestet, um zu zeigen, dass sich NE81 wie bereits bekannte Lamin-Proteine verh{\"a}lt und supramolekulare Netzwerke aus Laminfilamenten bildet. Zur Analyse der Struktur supramolekularer Anordnungen wurde das Protein durch Entfernen des Kernlokalisationssignals auf der {\"a}ußeren Kernh{\"u}lle von Dictyostelium gebildet. Die anschließende Untersuchung der Oberfl{\"a}che der Kerne mit einem Rasterelektronenmikroskop zeigte, dass NE81 Strukturen in der Gr{\"o}ße von Laminen bildet, allerdings nicht in regelm{\"a}ßigen filament{\"o}sen Anordnungen. Um die Entstehung der Laminfilamente zu untersuchen, wurde l{\"o}sliches NE81 aus Dictyostelium aufgereinigt und mit verschiedenen mikroskopischen Methoden untersucht. Dabei wurde festgestellt, dass NE81 unter Niedrigsalz-Bedingungen d{\"u}nne, fadenf{\"o}rmige Strukturen und Netzwerke ausbildet, die denen von S{\"a}ugetier-Laminen sehr {\"a}hnlich sind. Die Mutation der Phosphorylierungsstelle von NE81 zu einer imitierenden dauerhaften Phosphorylierung von NE81 in der Zelle, zeigte zun{\"a}chst ein gel{\"o}stes Protein, das {\"u}berraschenderweise unter Blaulichtbestrahlung der Zelle wieder lamin-{\"a}hnliche Anordnungen formte. Die Ergebnisse dieser Arbeit zeigen, dass NE81 echte Laminstrukturen ausbilden kann und hebt Dictyostelium als Nicht-S{\"a}ugetier-Modellorganismus mit einer gut charakterisierten Kernh{\"u}lle, mit allen relevanten, aus tierischen Zellen bekannten Proteinen, hervor.}, language = {en} } @phdthesis{Rector2019, author = {Rector, Michael V.}, title = {The acute effect of exercise on flow-mediated dilation in young people with cystic fibrosis}, doi = {10.25932/publishup-43893}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-438938}, school = {Universit{\"a}t Potsdam}, pages = {121}, year = {2019}, abstract = {Introduction: Cystic fibrosis (CF) is a genetic disease which disrupts the function of an epithelial surface anion channel, CFTR (cystic fibrosis transmembrane conductance regulator). Impairment to this channel leads to inflammation and infection in the lung causing the majority of morbidity and mortality. However, CF is a multiorgan disease affecting many tissues, including vascular smooth muscle. Studies have revealed young people with cystic fibrosis lacking inflammation and infection still demonstrate vascular endothelial dysfunction, measured per flow-mediated dilation (FMD). In other disease cohorts, i.e. diabetic and obese, endurance exercise interventions have been shown improve or taper this impairment. However, long-term exercise interventions are risky, as well as costly in terms of time and resources. Nevertheless, emerging research has correlated the acute effects of exercise with its long-term benefits and advocates the study of acute exercise effects on FMD prior to longitudinal studies. The acute effects of exercise on FMD have previously not been examined in young people with CF, but could yield insights on the potential benefits of long-term exercise interventions. The aims of these studies were to 1) develop and test the reliability of the FMD method and its applicability to study acute exercise effects; 2) compare baseline FMD and the acute exercise effect on FMD between young people with and without CF; and 3) explore associations between the acute effects of exercise on FMD and demographic characteristics, physical activity levels, lung function, maximal exercise capacity or inflammatory hsCRP levels. Methods: Thirty young volunteers (10 people with CF, 10 non-CF and 10 non-CF active matched controls) between the ages of 10 and 30 years old completed blood draws, pulmonary function tests, maximal exercise capacity tests and baseline FMD measurements, before returning approximately 1 week later and performing a 30-min constant load training at 75\% HRmax. FMD measurements were taken prior, immediately after, 30 minutes after and 1 hour after constant load training. ANOVAs and repeated measures ANOVAs were employed to explore differences between groups and timepoints, respectively. Linear regression was implemented and evaluated to assess correlations between FMD and demographic characteristics, physical activity levels, lung function, maximal exercise capacity or inflammatory hsCRP levels. For all comparisons, statistical significance was set at a p-value of α < 0.05. Results: Young people with CF presented with decreased lung function and maximal exercise capacity compared to matched controls. Baseline FMD was also significantly decreased in the CF group (CF: 5.23\% v non-CF: 8.27\% v non-CF active: 9.12\%). Immediately post-training, FMD was significantly attenuated (approximately 40\%) in all groups with CF still demonstrating the most minimal FMD. Follow-up measurements of FMD revealed a slow recovery towards baseline values 30 min post-training and improvements in the CF and non-CF active groups 60 min post-training. Linear regression exposed significant correlations between maximal exercise capacity (VO2 peak), BMI and FMD immediately post-training. Conclusion: These new findings confirm that CF vascular endothelial dysfunction can be acutely modified by exercise and will aid in underlining the importance of exercise in CF populations. The potential benefits of long-term exercise interventions on vascular endothelial dysfunction in young people with CF warrants further investigation.}, language = {en} } @phdthesis{Bieri2019, author = {Bieri, Pascal}, title = {Topmanager im Kreuzfeuer ihrer Dilemmata}, doi = {10.25932/publishup-44106}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-441062}, school = {Universit{\"a}t Potsdam}, pages = {XIII, 301}, year = {2019}, abstract = {Die vorliegende Forschungsarbeit untersucht den Umgang mit Dilemmata von Topmanagern. Dilemmata sind ein allt{\"a}gliches Gesch{\"a}ft im Topmanagement. Die entsprechenden Akteure sind daher immer wieder mit diesen konfrontiert und mit ihnen umzugehen, geh{\"o}rt gewissermaßen zu ihrer Berufsbeschreibung. Hinzu kommen Dilemmata im nicht direkt gesch{\"a}ftlichen Bereich, wie zum Beispiel jene zwischen Familien- und Arbeitszeit. Doch stellt dieses Feld ein kaum untersuchtes Forschungsgebiet dar. W{\"a}hrend Dilemmata in anderen Bereichen eine zunehmende Aufmerksamkeit erfuhren, wurden deren Besonderheiten im Topmanagement genauso wenig differenziert betrachtet wie zugeh{\"o}rige Umgangsweisen. Theorie und Praxis stellen bez{\"u}glich Dilemmata von Topmanagern vor allem einen Gegensatz dar, beziehungsweise fehlt es an einer theoretischen Fundierung der Empirie. Diesem Umstand wird mittels dieser Studie begegnet. Auf der Grundlage einer differenzierten und breiten Erfassung von Theorien zu Dilemmata, so diese auch noch nicht auf Topmanager bezogen wurden, und einer empirischen Erhebung, die im Mittelpunkt dieser Arbeit stehen, soll das Feld Dilemmata von Topmanagern der Forschung ge{\"o}ffnet werden. Empirische Grundlage sind vor allem narrative Interviews mit Topmanagern {\"u}ber ihre Dilemmata-Wahrnehmung, ausgemachte Ursachen, Umgangsweisen und Resultate. Dies erlaubt es, Topmanagertypen sowie Dilemmata-Arten, mit denen sie konfrontiert sind oder waren, analytisch herauszuarbeiten. Angesichts der Praxisrelevanz von Dilemmata von Topmanagern wird jedoch nicht nur ein theoretisches Modell zu dieser Thematik erarbeitet, es werden auch Reflexionen auf die Praxis in Form von Handlungsempfehlungen vorgenommen. Schließlich gilt es, die allgemeine Theorie zu Dilemmata, ohne konkreten Bezug zu Topmanagern, mit den theoretischen Erkenntnissen dieser Studie auf empirischer Basis zu kontrastieren. Dabei wird im Rahmen der empirischen Erfassung und Auswertung dem Ansatz der Grounded-Theory-Methodologie gefolgt.}, language = {de} } @phdthesis{Riemer2019, author = {Riemer, Janine}, title = {Synthese und Charakterisierung selektiver Fluoroionophore f{\"u}r intra- und extrazellul{\"a}re Bestimmungen von Kalium- und Natrium-Ionen}, doi = {10.25932/publishup-44193}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-441932}, school = {Universit{\"a}t Potsdam}, pages = {IV, 165}, year = {2019}, abstract = {Im Rahmen dieser Dissertation konnten neue Kalium- und Natrium-Ionen Fluoreszenzfarbstoffe von der Klasse der Fluoroionophore synthetisiert und charakterisiert werden. Sie bestehen aus einem N Phenylazakronenether als Ionophor und unterschiedlichen Fluorophoren und sind {\"u}ber einen π-konjugierten 1,2,3-Triazol-1,4-diyl Spacer verbunden. Dabei lag der Fokus w{\"a}hrend ihrer Entwicklung darauf, diese in ihrer Sensitivit{\"a}t, Selektivit{\"a}t und in ihren photophysikalischen Eigenschaften so zu funktionalisieren, dass sie f{\"u}r intra- bzw. extrazellul{\"a}re Konzentrationsbestimmungen geeignet sind. Durch Variation der in ortho Position der N-Phenylazakronenether befindlichen Alkoxy-Gruppen und der fluorophoren Gruppe der Fluoroionophore konnte festgestellt werden, dass die Sensitivit{\"a}t und Selektivit{\"a}t f{\"u}r Kalium- bzw. Natrium-Ionen jeweils durch eine bestimmte Isomerie der 1,2,3-Triazol-1,4-diyl-Einheit erh{\"o}ht wird. Des Weiteren wurde gezeigt, dass durch eine erh{\"o}hte Einschr{\"a}nkung der N,N-Diethylamino-Gruppe des Fluorophors eine Steigerung der Fluoreszenzquantenausbeute und eine Verschiebung des Emissionsmaximums auf {\"u}ber 500 nm erreicht werden konnte. Die Einf{\"u}hrung einer Isopropoxy-Gruppe an einem N-Phenylaza-[18]krone-6-ethers resultierte dabei in einem hoch selektiven Kalium-Ionen Fluoroionophor und erm{\"o}glichte eine in vitro {\"U}berwachung von 10 - 80 mM Kalium-Ionen. Die Substitution einer Methoxy-Gruppe an einem N-Phenylaza-[15]krone-5-ether kombiniert mit unterschiedlich N,N-Diethylamino-Coumarinen lieferte hingegen zwei Natrium-Ionen Fluoroionophore, die f{\"u}r die {\"U}berwachung von intra- bzw. extrazellul{\"a}ren Natrium-Ionen Konzentrationen geeignet sind. In einem weiteren Schritt wurden N-Phenylaza-[18]krone-6-ether mit einem Fluorophor, basierend auf einem [1,3]-Dioxolo[4,5-f][1,3]benzodioxol-(DBD)-Grundger{\"u}st, funktionalisiert. Die im Anschluss durchgef{\"u}hrten spektroskopischen Untersuchungen ergaben, dass die Isopropoxy-Gruppe in ortho Position des N-Phenylaza-[18]krone-6-ether in einen f{\"u}r extrazellul{\"a}re Kalium-Ionen Konzentrationen selektiven Fluoroionophor resultierte, der die Konzentrationsbestimmungen {\"u}ber die Fluoreszenzintensit{\"a}t und -lebensdauer erm{\"o}glicht. In einem abschließenden Schritt konnte unter Verwendung eines Pyrens als fluorophore Gruppe ein weiterer f{\"u}r extrazellul{\"a}re Kalium-Ionen Konzentrationen geeigneter Fluoroionophor entwickelt werden. Die Bestimmung der Kalium-Ionen Konzentration erfolgte hierbei anhand der Fluoreszenzintensit{\"a}tsverh{\"a}ltnisse bei zwei Emissionswellenl{\"a}ngen. Insgesamt konnten 17 verschiedene neue Fluoroionophore f{\"u}r die Bestimmung von Kalium- bzw. Natrium-Ionen synthetisiert und charakterisiert werden. Sechs dieser neuen Molek{\"u}le erm{\"o}glichen in vitro Messungen der intra- oder extrazellul{\"a}ren Kalium- und Natrium-Ionen Konzentrationen und k{\"o}nnten zuk{\"u}nftig f{\"u}r in vivo Konzentrationsmessungen verwendet werden.}, language = {de} } @phdthesis{Debsharma2019, author = {Debsharma, Tapas}, title = {Cellulose derived polymers}, doi = {10.25932/publishup-44131}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-441312}, school = {Universit{\"a}t Potsdam}, pages = {x, 103}, year = {2019}, abstract = {Plastics, such as polyethylene, polypropylene, and polyethylene terephthalate are part of our everyday lives in the form of packaging, household goods, electrical insulation, etc. These polymers are non-degradable and create many environmental problems and public health concerns. Additionally, these polymers are produced from finite fossils resources. With the continuous utilization of these limited resources, it is important to look towards renewable sources along with biodegradation of the produced polymers, ideally. Although many bio-based polymers are known, such as polylactic acid, polybutylene succinate adipate or polybutylene succinate, none have yet shown the promise of replacing conventional polymers like polyethylene, polypropylene and polyethylene terephthalate. Cellulose is one of the most abundant renewable resources produced in nature. It can be transformed into various small molecules, such as sugars, furans, and levoglucosenone. The aim of this research is to use the cellulose derived molecules for the synthesis of polymers. Acid-treated cellulose was subjected to thermal pyrolysis to obtain levoglucosenone, which was reduced to levoglucosenol. Levoglucosenol was polymerized, for the first time, by ring-opening metathesis polymerization (ROMP) yielding high molar mass polymers of up to ~150 kg/mol. The poly(levoglucosenol) is thermally stable up to ~220 ℃, amorphous, and is exhibiting a relatively high glass transition temperature of ~100 ℃. The poly(levoglucosenol) can be converted to a transparent film, resembling common plastic, and was found to degrade in a moist acidic environment. This means that poly(levoglucosenol) may find its use as an alternative to conventional plastic, for instance, polystyrene. Levoglucosenol was also converted into levoglucosenyl methyl ether, which was polymerized by cationic ring-opening metathesis polymerization (CROP). Polymers were obtained with molar masses up to ~36 kg/mol. These polymers are thermally stable up to ~220 ℃ and are semi-crystalline thermoplastics, having a glass transition temperature of ~35 ℃ and melting transition of 70-100 ℃. Additionally, the polymers underwent cross-linking, hydrogenation and thiol-ene click chemistry.}, language = {en} } @phdthesis{Meinig2019, author = {Meinig, Michael}, title = {Bedrohungsanalyse f{\"u}r milit{\"a}rische Informationstechnik}, doi = {10.25932/publishup-44160}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-441608}, school = {Universit{\"a}t Potsdam}, pages = {X, 137}, year = {2019}, abstract = {Risiken f{\"u}r Cyberressourcen k{\"o}nnen durch unbeabsichtigte oder absichtliche Bedrohungen entstehen. Dazu geh{\"o}ren Insider-Bedrohungen von unzufriedenen oder nachl{\"a}ssigen Mitarbeitern und Partnern, eskalierende und aufkommende Bedrohungen aus aller Welt, die stetige Weiterentwicklung der Angriffstechnologien und die Entstehung neuer und zerst{\"o}rerischer Angriffe. Informationstechnik spielt mittlerweile in allen Bereichen des Lebens eine entscheidende Rolle, u. a. auch im Bereich des Milit{\"a}rs. Ein ineffektiver Schutz von Cyberressourcen kann hier Sicherheitsvorf{\"a}lle und Cyberattacken erleichtern, welche die kritischen Vorg{\"a}nge st{\"o}ren, zu unangemessenem Zugriff, Offenlegung, {\"A}nderung oder Zerst{\"o}rung sensibler Informationen f{\"u}hren und somit die nationale Sicherheit, das wirtschaftliche Wohlergehen sowie die {\"o}ffentliche Gesundheit und Sicherheit gef{\"a}hrden. Oftmals ist allerdings nicht klar, welche Bedrohungen konkret vorhanden sind und welche der kritischen Systemressourcen besonders gef{\"a}hrdet ist. In dieser Dissertation werden verschiedene Analyseverfahren f{\"u}r Bedrohungen in milit{\"a}rischer Informationstechnik vorgeschlagen und in realen Umgebungen getestet. Dies bezieht sich auf Infrastrukturen, IT-Systeme, Netze und Anwendungen, welche Verschlusssachen (VS)/Staatsgeheimnisse verarbeiten, wie zum Beispiel bei milit{\"a}rischen oder Regierungsorganisationen. Die Besonderheit an diesen Organisationen ist das Konzept der Informationsr{\"a}ume, in denen verschiedene Datenelemente, wie z. B. Papierdokumente und Computerdateien, entsprechend ihrer Sicherheitsempfindlichkeit eingestuft werden, z. B. „STRENG GEHEIM", „GEHEIM", „VS-VERTRAULICH", „VS-NUR-F{\"U}R-DEN-DIENSTGEBRAUCH" oder „OFFEN". Die Besonderheit dieser Arbeit ist der Zugang zu eingestuften Informationen aus verschiedenen Informationsr{\"a}umen und der Prozess der Freigabe dieser. Jede in der Arbeit entstandene Ver{\"o}ffentlichung wurde mit Angeh{\"o}rigen in der Organisation besprochen, gegengelesen und freigegeben, so dass keine eingestuften Informationen an die {\"O}ffentlichkeit gelangen. Die Dissertation beschreibt zun{\"a}chst Bedrohungsklassifikationsschemen und Angreiferstrategien, um daraus ein ganzheitliches, strategiebasiertes Bedrohungsmodell f{\"u}r Organisationen abzuleiten. Im weiteren Verlauf wird die Erstellung und Analyse eines Sicherheitsdatenflussdiagramms definiert, welches genutzt wird, um in eingestuften Informationsr{\"a}umen operationelle Netzknoten zu identifizieren, die aufgrund der Bedrohungen besonders gef{\"a}hrdet sind. Die spezielle, neuartige Darstellung erm{\"o}glicht es, erlaubte und verbotene Informationsfl{\"u}sse innerhalb und zwischen diesen Informationsr{\"a}umen zu verstehen. Aufbauend auf der Bedrohungsanalyse werden im weiteren Verlauf die Nachrichtenfl{\"u}sse der operationellen Netzknoten auf Verst{\"o}ße gegen Sicherheitsrichtlinien analysiert und die Ergebnisse mit Hilfe des Sicherheitsdatenflussdiagramms anonymisiert dargestellt. Durch Anonymisierung der Sicherheitsdatenflussdiagramme ist ein Austausch mit externen Experten zur Diskussion von Sicherheitsproblematiken m{\"o}glich. Der dritte Teil der Arbeit zeigt, wie umfangreiche Protokolldaten der Nachrichtenfl{\"u}sse dahingehend untersucht werden k{\"o}nnen, ob eine Reduzierung der Menge an Daten m{\"o}glich ist. Dazu wird die Theorie der groben Mengen aus der Unsicherheitstheorie genutzt. Dieser Ansatz wird in einer Fallstudie, auch unter Ber{\"u}cksichtigung von m{\"o}glichen auftretenden Anomalien getestet und ermittelt, welche Attribute in Protokolldaten am ehesten redundant sind.}, language = {de} } @phdthesis{Knoechel2019, author = {Kn{\"o}chel, Jane}, title = {Model reduction of mechanism-based pharmacodynamic models and its link to classical drug effect models}, doi = {10.25932/publishup-44059}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-440598}, school = {Universit{\"a}t Potsdam}, pages = {vii, 147}, year = {2019}, abstract = {Continuous insight into biological processes has led to the development of large-scale, mechanistic systems biology models of pharmacologically relevant networks. While these models are typically designed to study the impact of diverse stimuli or perturbations on multiple system variables, the focus in pharmacological research is often on a specific input, e.g., the dose of a drug, and a specific output related to the drug effect or response in terms of some surrogate marker. To study a chosen input-output pair, the complexity of the interactions as well as the size of the models hinders easy access and understanding of the details of the input-output relationship. The objective of this thesis is the development of a mathematical approach, in specific a model reduction technique, that allows (i) to quantify the importance of the different state variables for a given input-output relationship, and (ii) to reduce the dynamics to its essential features -- allowing for a physiological interpretation of state variables as well as parameter estimation in the statistical analysis of clinical data. We develop a model reduction technique using a control theoretic setting by first defining a novel type of time-limited controllability and observability gramians for nonlinear systems. We then show the superiority of the time-limited generalised gramians for nonlinear systems in the context of balanced truncation for a benchmark system from control theory. The concept of time-limited controllability and observability gramians is subsequently used to introduce a state and time-dependent quantity called the input-response (ir) index that quantifies the importance of state variables for a given input-response relationship at a particular time. We subsequently link our approach to sensitivity analysis, thus, enabling for the first time the use of sensitivity coefficients for state space reduction. The sensitivity based ir-indices are given as a product of two sensitivity coefficients. This allows not only for a computational more efficient calculation but also for a clear distinction of the extent to which the input impacts a state variable and the extent to which a state variable impacts the output. The ir-indices give insight into the coordinated action of specific state variables for a chosen input-response relationship. Our developed model reduction technique results in reduced models that still allow for a mechanistic interpretation in terms of the quantities/state variables of the original system, which is a key requirement in the field of systems pharmacology and systems biology and distinguished the reduced models from so-called empirical drug effect models. The ir-indices are explicitly defined with respect to a reference trajectory and thereby dependent on the initial state (this is an important feature of the measure). This is demonstrated for an example from the field of systems pharmacology, showing that the reduced models are very informative in their ability to detect (genetic) deficiencies in certain physiological entities. Comparing our novel model reduction technique to the already existing techniques shows its superiority. The novel input-response index as a measure of the importance of state variables provides a powerful tool for understanding the complex dynamics of large-scale systems in the context of a specific drug-response relationship. Furthermore, the indices provide a means for a very efficient model order reduction and, thus, an important step towards translating insight from biological processes incorporated in detailed systems pharmacology models into the population analysis of clinical data.}, language = {en} } @phdthesis{Hanschmann2019, author = {Hanschmann, Raffael Tino}, title = {Stalling the engine? EU climate politics after the 'Great Recession'}, doi = {10.25932/publishup-44044}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-440441}, school = {Universit{\"a}t Potsdam}, pages = {XXVIII, 303}, year = {2019}, abstract = {This dissertation investigates the impact of the economic and fiscal crisis starting in 2008 on EU climate policy-making. While the overall number of adopted greenhouse gas emission reduction policies declined in the crisis aftermath, EU lawmakers decided to introduce new or tighten existing regulations in some important policy domains. Existing knowledge about the crisis impact on EU legislative decision-making cannot explain these inconsistencies. In response, this study develops an actor-centred conceptual framework based on rational choice institutionalism that provides a micro-level link to explain how economic crises translate into altered policy-making patterns. The core theoretical argument draws on redistributive conflicts, arguing that tensions between 'beneficiaries' and 'losers' of a regulatory initiative intensify during economic crises and spill over to the policy domain. To test this hypothesis and using social network analysis, this study analyses policy processes in three case studies: The introduction of carbon dioxide emission limits for passenger cars, the expansion of the EU Emissions Trading System to aviation, and the introduction of a regulatory framework for biofuels. The key finding is that an economic shock causes EU policy domains to polarise politically, resulting in intensified conflict and more difficult decision-making. The results also show that this process of political polarisation roots in the industry that is the subject of the regulation, and that intergovernmental bargaining among member states becomes more important, but also more difficult in times of crisis.}, language = {en} } @phdthesis{Ghani2019, author = {Ghani, Humaad}, title = {Structural evolution of the Kohat and Potwar fold and thrust belts of Pakistan}, doi = {10.25932/publishup-44077}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-440775}, school = {Universit{\"a}t Potsdam}, pages = {viii, 121}, year = {2019}, abstract = {Fold and thrust belts are characteristic features of collisional orogen that grow laterally through time by deforming the upper crust in response to stresses caused by convergence. The deformation propagation in the upper crust is accommodated by shortening along major folds and thrusts. The formation of these structures is influenced by the mechanical strength of d{\´e}collements, basement architecture, presence of preexisting structures and taper of the wedge. These factors control not only the sequence of deformation but also cause differences in the structural style. The Himalayan fold and thrust belt exhibits significant differences in the structural style from east to west. The external zone of the Himalayan fold and thrust belt, also called the Subhimalaya, has been extensively studied to understand the temporal development and differences in the structural style in Bhutan, Nepal and India; however, the Subhimalaya in Pakistan remains poorly studied. The Kohat and Potwar fold and thrust belts (herein called Kohat and Potwar) represent the Subhimalaya in Pakistan. The Main Boundary Thrust (MBT) marks the northern boundary of both Kohat and Potwar, showing that these belts are genetically linked to foreland-vergent deformation within the Himalayan orogen, despite the pronounced contrast in structural style. This contrast becomes more pronounced toward south, where the active strike-slip Kalabagh Fault Zone links with the Kohat and Potwar range fronts, known as the Surghar Range and the Salt Range, respectively. The Surghar and Salt Ranges developed above the Surghar Thrust (SGT) and Main Frontal Thrust (MFT). In order to understand the structural style and spatiotemporal development of the major structures in Kohat and Potwar, I have used structural modeling and low temperature thermochronolgy methods in this study. The structural modeling is based on construction of balanced cross-sections by integrating surface geology, seismic reflection profiles and well data. In order to constrain the timing and magnitude of exhumation, I used apatite (U-Th-Sm)/He (AHe) and apatite fission track (AFT) dating. The results obtained from both methods are combined to document the Paleozoic to Recent history of Kohat and Potwar. The results of this research suggest two major events in the deformation history. The first major deformation event is related to Late Paleozoic rifting associated with the development of the Neo-Tethys Ocean. The second major deformation event is related to the Late Miocene to Pliocene development of the Himalayan fold and thrust belt in the Kohat and Potwar. The Late Paleozoic rifting is deciphered by inverse thermal modelling of detrital AFT and AHe ages from the Salt Range. The process of rifting in this area created normal faulting that resulted in the exhumation/erosion of Early to Middle Paleozoic strata, forming a major unconformity between Cambrian and Permian strata that is exposed today in the Salt Range. The normal faults formed in Late Paleozoic time played an important role in localizing the Miocene-Pliocene deformation in this area. The combination of structural reconstructions and thermochronologic data suggest that deformation initiated at 15±2 Ma on the SGT ramp in the southern part of Kohat. The early movement on the SGT accreted the foreland into the Kohat deforming wedge, forming the range front. The development of the MBT at 12±2 Ma formed the northern boundary of Kohat and Potwar. Deformation propagated south of the MBT in the Kohat on double d{\´e}collements and in the Potwar on a single basal d{\´e}collement. The double d{\´e}collement in the Kohat adopted an active roof-thrust deformation style that resulted in the disharmonic structural style in the upper and lower parts of the stratigraphic section. Incremental shortening resulted in the development of duplexes in the subsurface between two d{\´e}collements and imbrication above the roof thrust. Tectonic thickening caused by duplexes resulted in cooling and exhumation above the roof thrust by removal of a thick sequence of molasse strata. The structural modelling shows that the ramps on which duplexes formed in Kohat continue as tip lines of fault propagation folds in the Potwar. The absence of a double d{\´e}collement in the Potwar resulted in the preservation of a thick sequence of molasse strata there. The temporal data suggest that deformation propagated in-sequence from ~ 8 to 3 Ma in the northern part of Kohat and Potwar; however, internal deformation in the Kohat was more intense, probably required for maintaining a critical taper after a significant load was removed above the upper d{\´e}collement. In the southern part of Potwar, a steeper basement slope (β≥3°) and the presence of salt at the base of the stratigraphic section allowed for the complete preservation of the stratigraphic wedge, showcased by very little internal deformation. Activation of the MFT at ~4 Ma allowed the Salt Range to become the range front of the Potwar. The removal of a large amount of molasse strata above the MFT ramp enhanced the role of salt in shaping the structural style of the Salt Range and Kalabagh Fault Zone. Salt accumulation and migration resulted in the formation of normal faults in both areas. Salt migration in the Kalabagh fault zone has triggered out-of-sequence movement on ramps in the Kohat. The amount of shortening calculated between the MBT and the SGT in Kohat is 75±5 km and between the MBT and the MFT in Potwar is 65±5 km. A comparable amount of shortening is accommodated in the Kohat and Potwar despite their different widths: 70 km Kohat and 150 km Potwar. In summary, this research suggests that deformation switched between different structures during the last ~15 Ma through different modes of fault propagation, resulting in different structural styles and the out-of-sequence development of Kohat and Potwar.}, language = {en} }