@phdthesis{Bendre2016,
  author    = {Bendre, Abhijit B.},
  title     = {Growth and saturation of dynamo in spiral galaxies via direct simulations},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-407517},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xviii, 133},
  year      = {2016},
  abstract  = {We do magnetohydrodynamic (MHD) simulations of local box models of turbulent Interstellar Medium (ISM) and analyse the process of amplification and saturation of mean magnetic fields with methods of mean field dynamo theory. It is shown that the process of saturation of mean fields can be partially described by the prolonged diffusion time scales in presence of the dynamically significant magnetic fields. However, the outward wind also plays an essential role in the saturation in higher SN rate case. Algebraic expressions for the back reaction of the magnetic field onto the turbulent transport coefficients are derived, which allow a complete description of the nonlinear dynamo. We also present the effects of dynamically significant mean fields on the ISM configuration and pressure distribution. We further add the cosmic ray component in the simulations and investigate the kinematic growth of mean fields with a dynamo perspective.},
  language  = {en}
}
@phdthesis{Bande2016,
  author    = {Bande, Alejandro},
  title     = {The tectonic evolution of the western Tien Shan},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-398933},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xiv, 119},
  year      = {2016},
  abstract  = {Intracontinental deformation usually is a result of tectonic forces associated with distant plate collisions. In general, the evolution of mountain ranges and basins in this environment is strongly controlled by the distribution and geometries of preexisting structures. Thus, predictive models usually fail in forecasting the deformation evolution in these kinds of settings. Detailed information on each range and basin-fill is vital to comprehend the evolution of intracontinental mountain belts and basins. In this dissertation, I have investigated the complex Cenozoic tectonic evolution of the western Tien Shan in Central Asia, which is one of the most active intracontinental ranges in the world. The work presented here combines a broad array of datasets, including thermo- and geochronology, paleoenvironmental interpretations, sediment provenance and subsurface interpretations in order to track changes in tectonic deformation. Most of the identified changes are connected and can be related to regional-scale processes that governed the evolution of the western Tien Shan. The NW-SE trending Talas-Fergana fault (TFF) separates the western from the central Tien Shan and constitutes a world-class example of the influence of preexisting anisotropies on the subsequent structural development of a contractile orogen. While to the east most of ranges and basins have a sub-parallel E-W trend, the triangular-shaped Fergana basin forms a substantial feature in the western Tien Shan morphology with ranges on all three sides. In this thesis, I present 55 new thermochronologic ages (apatite fission track and zircon (U-Th)/He)) used to constrain exhumation histories of several mountain ranges in the western Tien Shan. At the same time, I analyzed the Fergana basin-fill looking for progressive changes in sedimentary paleoenvironments, source areas and stratal geometrical configurations in the subsurface and outcrops. The data presented in this thesis suggests that low cooling rates (<1°C Myr-1), calm depositional environments, and low depositional rates (<10 m Myr-1) were widely distributed across the western Tien Shan, describing a quiescent tectonic period throughout the Paleogene. Increased cooling rates in the late Cenozoic occurred diachronously and with variable magnitudes in different ranges. This rapid cooling stage is interpreted to represent increased erosion caused by active deformation and constrains the onset of Cenozoic deformation in the western Tien Shan. Time-temperature histories derived from the northwestern Tien Shan samples show an increase in cooling rates by ~25 Ma. This event is correlated with a synchronous pulse iv in the South Tien Shan. I suggest that strike-slip motion along the TFF commenced at the Oligo-Miocene boundary, facilitating CCW rotation of the Fergana basin and enabling exhumation of the linked horsetail splays. Higher depositional rates (~150 m Myr-1) in the Oligo-Miocene section (Massaget Fm.) of the Fergana basin suggest synchronous deformation in the surrounding ranges. The central Alai Range also experienced rapid cooling around this time, suggesting that the onset of intramontane basin fragmentation and isolation is coeval. These results point to deformation starting simultaneously in the late Oligocene - early Miocene in geographically distant mountain ranges. I suggest that these early uplifts are controlled by reactivated structures (like the TFF), which are probably the frictionally weakest and most-suitably oriented for accommodating and transferring N-S horizontal shortening along the western Tien Shan. Afterwards, in the late Miocene (~10 Ma), a period of renewed rapid cooling affected the Tien Shan and most mountain ranges and inherited structures started to actively deform. This episode is widely distributed and an increase in exhumation is interpreted in most of the sampled ranges. Moreover, the Pliocene section in the basin subsurface shows the higher depositional rates (>180 m Myr-1) and higher energy facies. The deformation and exhumation increase further contributed to intramontane basin partitioning. Overall, the interpretation is that the Tien Shan and much of Central Asia suffered a global increase in the rate of horizontal crustal shortening. Previously, stress transfer along the rigid Tarim block or Pamir indentation has been proposed to account for Himalayan hinterland deformation. However, the extent of the episode requires a different and broader geodynamic driver.},
  language  = {en}
}
@phdthesis{Audoersch2016,
  author    = {Aud{\"o}rsch, Stephan},
  title     = {Die Synthese von (2Z,4E)-Diencarbons{\"a}ureestern und ihre Anwendung in der Totalsynthese von Polyacetylenen},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-92366},
  school      = {Universit{\"a}t Potsdam},
  pages     = {139},
  year      = {2016},
  abstract  = {Z,E-Diene sind ein h{\"a}ufig auftretendes Strukturmerkmal in Naturstoffen. Aus diesem Grund ist die einfache Darstellung dieser Struktureinheit von großen Interesse in der organischen Chemie. Das erste Ziel der vorliegenden Arbeit war daher die Weiterentwicklung der Ringschlussmetathese-/ baseninduzierten Ring{\"o}ffnungs-/ Veresterungssequenz (RBRV-Sequenz) zur Synthese von (2Z,4E)-Diencarbons{\"a}ureethylestern ausgehend von Butenoaten. Dazu wurde zun{\"a}chst die RBRV-Sequenz optimiert. Diese aus drei Schritten bestehende Sequenz konnte in einem Eintopf-Verfahren angewendet werden. Die Ringschlussmetathese gelang mit einer Katalysatorbeladung von 1 mol\% des GRUBBS-Katalysators der zweiten Generation in Dichlormethan. F{\"u}r die baseninduzierte Ring{\"o}ffnung des β,γ-unges{\"a}ttigten δ Valerolactons wurde NaHMDS verwendet. Die Alkylierung der Carboxylatspezies gelang mit dem MEERWEIN-Reagenz. Die Anwendbarkeit der Sequenz wurde f{\"u}r verschiedene Substrate demonstriert. Die Erweiterung der Methode auf α-substituierte Butenoate unterlag starken Einschr{\"a}nkungen. So konnte der Zugang f{\"u}r α Hydroxyderivate realisiert werden. Bei der Anwendung der RBRV-Sequenz auf die α-substituierten Butenoate wurde festgestellt, dass diese sich nur in moderaten Ausbeuten umsetzen ließen und zudem nicht selektiv zu den (2E,4E)-konfigurierten α-substituierten-Dienestern reagierten. Der Einsatz von Eninen unter den Standardbedingungen der RBRV-Sequenz gelang nicht. Erst nach Modifizierung der Sequenz (h{\"o}here Katalysatorbeladung, Wechsel des L{\"o}sungsmittels) konnten die [3]Dendralen-Produkte in geringen Ausbeuten erhalten werden. Im zweiten Teil der Arbeit wurde der Einsatz von (2Z,4E)-Diencarbons{\"a}ureethylestern in der Totalsynthese von Naturstoffen untersucht. Dazu wurden zun{\"a}chst die Transformationsm{\"o}glichkeiten der Ester gepr{\"u}ft. Es konnte gezeigt werden, dass sich (2Z,4E)-Diencarbons{\"a}ureethylester insbesondere zur Synthese von (2Z,4E)-Aldehyden sowie zum Aufbau der (3Z,5E)-Dien-1-in-Struktur eignen. Anhand dieser Ergebnisse wurde im Anschluss die RBRV-Sequenz in der Totalsynthese eingesetzt. Dazu wurde zun{\"a}chst der (2Z,4E)-Dienester Microsphaerodiolin in seiner ersten Totalsynthese auf drei verschiedene Routen hergestellt. Im Anschluss wurden sechs verschiedene Polyacetylene mit einer (3Z,5E)-Dien-1-in-Einheit hergestellt. Schl{\"u}sselschritte in ihrer Synthese waren immer die RBRV-Sequenz zum Aufbau der Z,E-Dien-Einheit, die Transformation des Esters in ein terminales Alkin sowie die CADIOT-CHODKIEWICZ-Kupplung zum Aufbau unsymmetrischer Polyine. Alle sechs Polyacetylene wurden zum ersten Mal in einer Totalsynthese synthetisiert. Drei Polyacetylene wurden ausgehend von (S)-Butantriol enantiomerenrein dargestellt. Anhand ihrer Drehwerte konnte eine Revision der von YAO und Mitarbeitern vorgenommen Zuordnung der Absolutkonfiguration der Naturstoffe vorgenommen werden.},
  language  = {de}
}
@phdthesis{Ata2016,
  author    = {Ata, Metin},
  title     = {Phase-space reconstructions of cosmic velocities and the cosmic web},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-403565},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xi, 155},
  year      = {2016},
  abstract  = {In the current paradigm of cosmology, the formation of large-scale structures is mainly driven by non-radiating dark matter, making up the dominant part of the matter budget of the Universe. Cosmological observations however, rely on the detection of luminous galaxies, which are biased tracers of the underlying dark matter. In this thesis I present cosmological reconstructions of both, the dark matter density field that forms the cosmic web, and cosmic velocities, for which both aspects of my work are delved into, the theoretical formalism and the results of its applications to cosmological simulations and also to a galaxy redshift survey.The foundation of our method is relying on a statistical approach, in which a given galaxy catalogue is interpreted as a biased realization of the underlying dark matter density field. The inference is computationally performed on a mesh grid by sampling from a probability density function, which describes the joint posterior distribution of matter density and the three dimensional velocity field. The statistical background of our method is described in Chapter "Implementation of argo", where the introduction in sampling methods is given, paying special attention to Markov Chain Monte-Carlo techniques. In Chapter "Phase-Space Reconstructions with N-body Simulations", I introduce and implement a novel biasing scheme to relate the galaxy number density to the underlying dark matter, which I decompose into a deterministic part, described by a non-linear and scale-dependent analytic expression, and a stochastic part, by presenting a negative binomial (NB) likelihood function that models deviations from Poissonity. Both bias components had already been studied theoretically, but were so far never tested in a reconstruction algorithm. I test these new contributions againstN-body simulations to quantify improvements and show that, compared to state-of-the-art methods, the stochastic bias is inevitable at wave numbers of k≥0.15h Mpc^-1 in the power spectrum in order to obtain unbiased results from the reconstructions. In the second part of Chapter "Phase-Space Reconstructions with N-body Simulations" I describe and validate our approach to infer the three dimensional cosmic velocity field jointly with the dark matter density. I use linear perturbation theory for the large-scale bulk flows and a dispersion term to model virialized galaxy motions, showing that our method is accurately recovering the real-space positions of the redshift-space distorted galaxies. I analyze the results with the isotropic and also the two-dimensional power spectrum.Finally, in Chapter "Phase-space Reconstructions with Galaxy Redshift Surveys", I show how I combine all findings and results and apply the method to the CMASS (for Constant (stellar) Mass) galaxy catalogue of the Baryon Oscillation Spectroscopic Survey (BOSS). I describe how our method is accounting for the observational selection effects inside our reconstruction algorithm. Also, I demonstrate that the renormalization of the prior distribution function is mandatory to account for higher order contributions in the structure formation model, and finally a redshift-dependent bias factor is theoretically motivated and implemented into our method. The various refinements yield unbiased results of the dark matter until scales of k≤0.2 h Mpc^-1in the power spectrum and isotropize the galaxy catalogue down to distances of r∼20h^-1 Mpc in the correlation function. We further test the results of our cosmic velocity field reconstruction by comparing them to a synthetic mock galaxy catalogue, finding a strong correlation between the mock and the reconstructed velocities. The applications of both, the density field without redshift-space distortions, and the velocity reconstructions, are very broad and can be used for improved analyses of the baryonic acoustic oscillations, environmental studies of the cosmic web, the kinematic Sunyaev-Zel'dovic or integrated Sachs-Wolfe effect.},
  language  = {en}
}
@phdthesis{Antoniewicz2016,
  author    = {Antoniewicz, Franziska},
  title     = {Automatic evaluations of exercising},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-92280},
  school      = {Universit{\"a}t Potsdam},
  year      = {2016},
  abstract  = {Changing the perspective sometimes offers completely new insights to an already well-known phenomenon. Exercising behavior, defined as planned, structured and repeated bodily movements with the intention to maintain or increase the physical fitness (Caspersen, Powell, \& Christenson, 1985), can be thought of as such a well-known phenomenon that has been in the scientific focus for many decades (Dishman \& O'Connor, 2005). Within these decades a perspective that assumes rational and controlled evaluations as the basis for decision making, was predominantly used to understand why some people engage in physical activity and others do not (Ekkekakis \& Zenko, 2015). Dual-process theories (Ekkekakis \& Zenko, 2015; Payne \& Gawronski, 2010) provide another perspective, that is not exclusively influenced by rational reasoning. These theories differentiate two different processes that guide behavior "depending on whether they operate automatically or in a controlled fashion" (Gawronski \& Creighton, 2012, p. 282). Following this line of thought, exercise behavior is not solely influenced by thoughtful deliberations (e.g. concluding that exercising is healthy) but also by spontaneous affective reactions (e.g. disliking being sweaty while exercising). The theoretical frameworks of dual-process models are not new in psychology (Chaiken \& Trope, 1999) and have already been used for the explanation of numerous behaviors (e.g. Hofmann, Friese, \& Wiers, 2008; Huijding, de Jong, Wiers, \& Verkooijen, 2005). However, they have only rarely been used for the explanation of exercise behavior (e.g. Bluemke, Brand, Schweizer, \& Kahlert, 2010; Conroy, Hyde, Doerksen, \& Ribeiro, 2010; Hyde, Doerksen, Ribeiro, \& Conroy, 2010). The assumption of two dissimilar behavior influencing processes, differs fundamentally from previous theories and thus from the research that has been conducted in the last decades in exercise psychology. Research mainly concentrated on predictors of the controlled processes and addressed the identified predictors in exercise interventions (Ekkekakis \& Zenko, 2015; Hagger, Chatzisarantis, \& Biddle, 2002). Predictors arising from the described automatic processes, for example automatic evaluations for exercising (AEE), have been neglected in exercise psychology for many years. Until now, only a few researchers investigated the influence of these AEE for exercising behavior (Bluemke et al., 2010; Brand \& Schweizer, 2015; Markland, Hall, Duncan, \& Simatovic, 2015). Marginally more researchers focused on the impact of AEE for physical activity behavior (Calitri, Lowe, Eves, \& Bennett, 2009; Conroy et al., 2010; Hyde et al., 2010; Hyde, Elavsky, Doerksen, \& Conroy, 2012). The extant studies mainly focused on the quality of AEE and the associated quantity of exercise (exercise much or little; Bluemke et al., 2010; Calitri et al., 2009; Conroy et al., 2010; Hyde et al., 2012). In sum, there is still a dramatic lack of empirical knowledge, when applying dual-process theories to exercising behavior, even though these theories have proven to be successful in explaining behavior in many other health-relevant domains like eating, drinking or smoking behavior (e.g. Hofmann et al., 2008). The main goal of the present dissertation was to collect empirical evidence for the influence of AEE on exercise behavior and to expand the so far exclusively correlational studies by experimentally controlled studies. By doing so, the ongoing debate on a paradigm shift from controlled and deliberative influences of exercise behavior towards approaches that consider automatic and affective influences (Ekkekakis \& Zenko, 2015) should be encouraged. All three conducted publications are embedded in dual-process theorizing (Gawronski \& Bodenhausen, 2006, 2014; Strack \& Deutsch, 2004). These theories offer a theoretical framework that could integrate the established controlled variables of exercise behavior explanation and additionally consider automatic factors for exercise behavior like AEE. Taken together, the empirical findings collected suggest that AEE play an important and diverse role for exercise behavior. They represent exercise setting preferences, are a cause for short-term exercise decisions and are decisive for long-term exercise adherence. Adding to the few already present studies in this field, the influence of (positive) AEE for exercise behavior was confirmed in all three presented publications. Even though the available set of studies needs to be extended in prospectively studies, first steps towards a more complete picture have been taken. Closing with the beginning of the synopsis: I think that time is right for a change of perspectives! This means a careful extension of the present theories with controlled evaluations explaining exercise behavior. Dual-process theories including controlled and automatic evaluations could provide such a basis for future research endeavors in exercise psychology.},
  language  = {en}
}
@phdthesis{AlSaffar2016,
  author    = {Al-Saffar, Loay Talib Ahmed},
  title     = {Analysing prerequisites, expectations, apprehensions, and attitudes of university students studying Computer science},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-98437},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xii, 131},
  year      = {2016},
  abstract  = {The main objective of this dissertation is to analyse prerequisites, expectations, apprehensions, and attitudes of students studying computer science, who are willing to gain a bachelor degree. The research will also investigate in the students' learning style according to the Felder-Silverman model. These investigations fall in the attempt to make an impact on reducing the "dropout"/shrinkage rate among students, and to suggest a better learning environment. The first investigation starts with a survey that has been made at the computer science department at the University of Baghdad to investigate the attitudes of computer science students in an environment dominated by women, showing the differences in attitudes between male and female students in different study years. Students are accepted to university studies via a centrally controlled admission procedure depending mainly on their final score at school. This leads to a high percentage of students studying subjects they do not want. Our analysis shows that 75\% of the female students do not regret studying computer science although it was not their first choice. And according to statistics over previous years, women manage to succeed in their study and often graduate on top of their class. We finish with a comparison of attitudes between the freshman students of two different cultures and two different university enrolment procedures (University of Baghdad, in Iraq, and the University of Potsdam, in Germany) both with opposite gender majority. The second step of investigation took place at the department of computer science at the University of Potsdam in Germany and analyzes the learning styles of students studying the three major fields of study offered by the department (computer science, business informatics, and computer science teaching). Investigating the differences in learning styles between the students of those study fields who usually take some joint courses is important to be aware of which changes are necessary to be adopted in the teaching methods to address those different students. It was a two stage study using two questionnaires; the main one is based on the Index of Learning Styles Questionnaire of B. A. Solomon and R. M. Felder, and the second questionnaire was an investigation on the students' attitudes towards the findings of their personal first questionnaire. Our analysis shows differences in the preferences of learning style between male and female students of the different study fields, as well as differences between students with the different specialties (computer science, business informatics, and computer science teaching). The third investigation looks closely into the difficulties, issues, apprehensions and expectations of freshman students studying computer science. The study took place at the computer science department at the University of Potsdam with a volunteer sample of students. The goal is to determine and discuss the difficulties and issues that they are facing in their study that may lead them to think in dropping-out, changing the study field, or changing the university. The research continued with the same sample of students (with business informatics students being the majority) through more than three semesters. Difficulties and issues during the study were documented, as well as students' attitudes, apprehensions, and expectations. Some of the professors and lecturers opinions and solutions to some students' problems were also documented. Many participants had apprehensions and difficulties, especially towards informatics subjects. Some business informatics participants began to think of changing the university, in particular when they reached their third semester, others thought about changing their field of study. Till the end of this research, most of the participants continued in their studies (the study they have started with or the new study they have changed to) without leaving the higher education system.},
  language  = {en}
}