@phdthesis{Schieffer2012,
  author    = {Schieffer, Andre},
  title     = {Studies on diversity and coexistence in an experimental microbial community},
  pages     = {76 Bl. : Ill.},
  year      = {2012},
  abstract  = {Biodiversity and the coexistence of species have puzzled and fascinated biologists since decades and is a hotspot in todays' natural sciences. Preserving this biodiversity is a great challenge as habitats and environments underlying tremendous changes like climate change and the loss of natural habitats, which are mainly due to anthropogenic influences. The coexistence of numerous species even in homogeneous environments is a stunning feature of natural communities and has been summarized under the term 'paradox of plankton'. Up to now, there are several mechanisms discussed, which may contribute to local and global diversity of organisms. Several interspecific trade offs have been identified maintaining the coexistence of species like their abilities regarding competition and predator avoidance, their capability to disperse in space and time, and their ability to exploit variable resources. Further, micro-evolutionary dynamics supporting the coexistence of species have been added to our knowledge, and deriving from theoretical deterministic models, non-linear dynamics which describe the temporal fluctuation of abundances of organisms. Whereas competition and predation seem to be clue structural elements within interacting organisms, the intrinsic dynamic behavior - by means of temporal changes in abundance - plays an important role regarding coexistence within a community. The present work sheds light on different factors affecting the coexistence of species using experimental microbial model systems consisting of a bacterivorous ciliate as the predator and two bacteria strains as prey organism. Additionally, another experimental setup consisting of two up to five bacteria species competing for one limiting resource was investigated. Highly controllable chemostat systems were established to exclude extrinsic disturbances. According to theoretical analyses I was able to show - experimentally and theoretically - that phenotypic plasticity of one species within a microbial one-predator-two-prey food web enlarges the range of possible coexistence of all species under different dynamic conditions, compared to a food web without phenotypic plasticity. This was accompanied by non-linear (chaotic) population dynamics within all experimental systems showing phenotypic plasticity. The experiments on the interplay of competition, predation and invasion showed that all aspects have an influence on species coexistence. Under undisturbed controlled conditions all aspects were analyzed in detail and in combination. Populations showed oscillations which were shown by quasi-chaotic attractors in phase space diagrams. Competition experiments with two up to five bacteria species competing for one limiting resource showed that all organisms were able to coexist which was mediated by species oscillations entering a regime of chaos. Besides that fact it was found, that the productivity (biomass) as well as the total cell numbers - under the same nutrition supply - increased by an increasing number of species in the experimental systems. Up to now, the occurrence of non-linear dynamics in well controlled experimental studies has been recognized several times and this phenomenon seemed to be more common in natural systems than generally assumed.},
  language  = {en}
}
@phdthesis{Hellmanns2012,
  author    = {Hellmanns, Mark},
  title     = {Qualit{\"a}tssicherung von handgef{\"u}hrten Applikationsprozessen durch Nachverfolgung der Handhabungseinheit. (Fortschrittsberichte aus der Produktionstechnik ; 1)},
  publisher = {Aachen},
  address   = {Shaker},
  isbn      = {978-3-8440-1379-5},
  pages     = {XIV, 99 S. : Ill., graph. Darst.},
  year      = {2012},
  language  = {de}
}
@phdthesis{Bragard2012,
  author    = {Bragard, Michael},
  title     = {The integrated emitter turn-off thyristor : an innovative MOS-gated high-power device. - (Aachener Beitr{\"a}ge des ISEA ; 62)},
  publisher = {Shaker},
  address   = {Aachen},
  isbn      = {978-3-8440-1152-4},
  pages     = {III, 164 S. : Ill., graph. Darst.},
  year      = {2012},
  abstract  = {This thesis introduces the Integrated Emitter Turn-Off (IETO) Thyristor as a new high-power device. Known state-of-the-art research activities like the Dual GCT, the ETO thyristor and the ICT were presented and critically reviewed. A comparison with commercialized solutions identifies the pros and cons of each type of device family. Based on this analysis, the IETO structure is proposed, covering most benefits of each device class. In particular the combination of a MOS-assisted turn-off with a thyristor-based device allows a voltage-controlled MOS switching and the low on-state voltage of the thyristors. The following synthesis of an IETO device stands on a three-dimensional field of optimization spanned by electric, mechanical and thermal aspects. From an electric point of view, the lowest possible parasitic inductance and resistance within the commutation path are optimization criteria. The mechanical construction has to withstand the required contact pressure of multiple kilo Newtons. Finally, thermal borders limit the maximum average current of the device. FEM simulations covering these three aspects are performed for several design proposals. An IETO prototype is constructed and measurements on various test benches attest thermal, mechanical and electric performance. A local decoupling of the external driver stage and the presspack housing is presented by a cable connection. This separation enables a thermal and mechanical independence, which is advantageous in terms of vibrations and thermal cycles including increased reliability. The electric pulse performance of the prototype device is a factor of 3.1 above today''s solutions. In single-pulse measurements, a current up to 1600 A was successfully turned off at 115°C with an active silicon area of 823 mm². One reason for this increased turn-off capability is the extremely low-inductive construction. Additional functionality of the IETO thyristor like over-current self-protection and defined short-circuit failure state are successfully verified.},
  language  = {en}
}
@phdthesis{Oflaz2012,
  author    = {Oflaz, Hakan},
  title     = {Entwicklung eines Prototypen zur Prognose von Fr{\"u}hgeburten : ein biomedizintechnischer Ansatz},
  publisher = {Deutsche Zentralbibliothek f{\"u}r Medizin},
  address   = {K{\"o}ln},
  doi       = {10.4126/38m-004639208},
  year      = {2012},
  language  = {en}
}
@phdthesis{KurulganDemirci2012,
  author    = {Kurulgan Demirci, Eylem},
  title     = {The effect of rhAPC on contractile tension : an in-vitro sepsis model of cardiomyocytes and endothelial cells},
  year      = {2012},
  language  = {en}
}
@phdthesis{Buedenbender2012,
  author    = {B{\"u}denbender, Martin},
  title     = {Entflechtungskonzepte f{\"u}r Strom{\"u}bertragungsnetze : ein {\"o}konomischer Vergleich},
  series = {M{\"u}nstersche Schriften zur Kooperation ; Bd. 101},
  journal   = {M{\"u}nstersche Schriften zur Kooperation ; Bd. 101},
  publisher = {Shaker},
  address   = {D{\"u}ren},
  isbn      = {978-3-8440-1460-0},
  pages     = {XVII, 401 S. : Ill., graph. Darst.},
  year      = {2012},
  abstract  = {Netzsektoren und deren ad{\"a}quate Regulierung sind ein sehr relevantes und aktuelles Thema. Dies gilt sowohl f{\"u}r die {\"o}konomische Theorie, die sich sehr intensiv damit auseinandersetzt und in den letzten Jahrzehnten zahlreiche neue Erkenntnisse gewonnen hat. Es gilt ebenso f{\"u}r die Politik, in der Regulierungsfragen kontrovers diskutiert werden und dies nicht nur unter {\"o}konomischen Gesichtspunkten. Es gilt selbstverst{\"a}ndlich f{\"u}r die regulierten Unternehmen selbst, deren T{\"a}tigkeit durch die staatlichen Regulierungsvorgaben markant beeinflusst wird. Nicht nur die konkreten Inhalte der Regulierungsregime sowie die verbleibenden Freiheitsgrade in der Ausgestaltung sind von Bedeutung, sondern ebenso die Umsetzung durch die Regulierungsbeh{\"o}rden. All dies gilt f{\"u}r den Strommarkt und seinen regulatorischen Hintergrund in besonderer Weise. Die Entflechtung der Strom{\"u}bertragungsnetze von der Stromproduktion und damit die Vorgaben f{\"u}r die Organisation der Wertsch{\"o}pfungsketten in den Elektrizit{\"a}tsunternehmen sind seit dem Beginn des europ{\"a}ischen Liberalisierungsprozesses der Stromm{\"a}rkte ein wichtiges und kontrovers diskutiertes Regulierungselement. Den Fokus bildet das vertikale Unbundling, das letztlich die Diskriminierung von Wettbewerbern durch Anbieter mit aggregierten Wertsch{\"o}pfungsketten verhindern soll, indem diese gezwungen werden, ihren "Netzteil" anders zu organisieren oder zu verkaufen. Den Mitgliedsstaaten blieben Freir{\"a}ume in der Ausgestaltung, die in Deutschland erst vor kurzem konkretisiert wurden, und die f{\"u}r die regulierten Unternehmen die Nutzung eines Wahlrechts beinhalten. Der wirtschaftspolitischen folgt nun eine unternehmerische Abw{\"a}gungsentscheidung.},
  language  = {de}
}