@phdthesis{Siddiqui2017, author = {Siddiqui, Tarique Adnan}, title = {Long-term investigation of the lunar tide in the equatorial electrojet during stratospheric sudden warmings}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-406384}, school = {Universit{\"a}t Potsdam}, pages = {xvii, 116}, year = {2017}, abstract = {The ionosphere, which is strongly influenced by the Sun, is known to be also affected by meteorological processes. These processes, despite having their origin in the troposphere and stratosphere, interact with the upper atmosphere. Such an interaction between atmospheric layers is known as vertical coupling. During geomagnetically quiet times, when near-Earth space is not under the influence of solar storms, these processes become important drivers for ionospheric variability. Studying the link between these processes in the lower atmosphere and the ionospheric variability is important for our understanding of fundamental mechanisms in ionospheric and meteorological research. A prominent example of vertical coupling between the stratosphere and the ionosphere are the so-called stratospheric sudden warming (SSW) events that occur usually during northern winters and result in an increase in the polar stratospheric temperature and a reversal of the circumpolar winds. While the phenomenon of SSW is confined to the northern polar stratosphere, its influence on the ionosphere can be observed even at equatorial latitudes. During SSW events, the connection between the polar stratosphere and the equatorial ionosphere is believed to be through the modulation of global atmospheric tides. These tides are fundamental for the ionospheric E-region wind dynamo that generates electric fields and currents in the ionosphere. Observations of ionospheric currents indicate a large enhancement of the semidiurnal lunar tide in response to SSW events. Thus, the semidiurnal lunar tide becomes an important driver of ionospheric variability during SSW events. In this thesis, the ionospheric effect of SSW events is investigated in the equatorial region, where a narrow but an intense E-region current known as the equatorial electrojet (EEJ) flows above the dip equator during the daytime. The day-to-day variability of the EEJ can be determined from magnetic field records at geomagnetic observatories close to the dip equator. Such magnetic data are available for several decades and allows to investigate the impact of SSW events on the EEJ and, even more importantly, helps in understanding the effects of SSW events on the equatorial ionosphere. An excellent long-term record of the geomagnetic field at the equator from 1922 onwards is available for the observatory Huancayo in Peru and is extensively utilized in this study. The central subject of this thesis is the investigation of lunar tides in the EEJ during SSW events by analyzing long time series. This is done by estimating the lunar tidal amplitude in the EEJ from the magnetic records at Huancayo and by comparing them to measurements of the polar stratospheric wind and temperature, which led to the identification of the known SSW events from 1952 onwards. One goal of this thesis is to identify SSW events that predate 1952. To this end, superposed epoch analysis (SEA) is employed to establish a relationship between the lunar tidal power and the wind and temperature conditions in the lower atmosphere. A threshold value for the lunar tidal power is identified that is discriminative for the known SSW events. This threshold is then used to identify lunar tidal enhancements, which are indicative for any historic SSW events prior to 1952. It can be shown, that the number of lunar tidal enhancements and thus the occurrence frequency of historic SSW events between 1926 and 1952 is similar to the occurrence frequency of the known SSW events from 1952 onwards. Next to the classic SSW definition, the concept of polar vortex weakening (PVW) is utilized in this thesis. PVW is defined for higher latitudes and altitudes (≈ 40km) than the classical SSW definition (≈ 32km). The correlation between the timing and magnitude of lunar tidal enhancements in the EEJ and the timing and magnitude of PVW is found to be better than for the classic SSW definition. This suggests that the lunar tidal enhancements in the EEJ are closely linked to the state of the middle atmosphere. Geomagnetic observatories located in different longitudes at the dip equator allow investigating the longitudinally dependent variability of the EEJ during SSW events. For this purpose, the lunar tidal enhancements in the EEJ are determined for the Peruvian and Indian sectors during the major SSW events of the years 2006 and 2009. It is found that the lunar tidal amplitude shows similar enhancements in the Peruvian sector during both SSW events, while the enhancements are notably different for the two events in the Indian sector. In summary, this thesis shows that lunar tidal enhancements in the EEJ are indeed correlated to the occurrence of SSW events and they should be considered a prominent driver of low latitude ionospheric variability. Secondly, lunar tidal enhancements are found to be longitudinally variable. This suggests that regional effects, such as ionospheric conductivity and the geometry and strength of the geomagnetic field, also play an important role and have to be considered when investigating the mechanisms behind vertical coupling.}, language = {en} } @phdthesis{Shenar2017, author = {Shenar, Tomer}, title = {Comprehensive analyses of massive binaries and implications on stellar evolution}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-104857}, school = {Universit{\"a}t Potsdam}, pages = {187}, year = {2017}, abstract = {Via their powerful radiation, stellar winds, and supernova explosions, massive stars (Mini \& 8 M☉) bear a tremendous impact on galactic evolution. It became clear in recent decades that the majority of massive stars reside in binary systems. This thesis sets as a goal to quantify the impact of binarity (i.e., the presence of a companion star) on massive stars. For this purpose, massive binary systems in the Local Group, including OB-type binaries, high mass X-ray binaries (HMXBs), and Wolf-Rayet (WR) binaries, were investigated by means of spectral, orbital, and evolutionary analyses. The spectral analyses were performed with the non-local thermodynamic equillibrium (non-LTE) Potsdam Wolf-Rayet (PoWR) model atmosphere code. Thanks to critical updates in the calculation of the hydrostatic layers, the code became a state-of-the-art tool applicable for all types of hot massive stars (Chapter 2). The eclipsing OB-type triple system δ Ori served as an intriguing test-case for the new version of the PoWR code, and provided key insights regarding the formation of X-rays in massive stars (Chapter 3). We further analyzed two prototypical HMXBs, Vela X-1 and IGR J17544-2619, and obtained fundamental conclusions regarding the dichotomy of two basic classes of HMXBs (Chapter 4). We performed an exhaustive analysis of the binary R 145 in the Large Magellanic Cloud (LMC), which was claimed to host the most massive stars known. We were able to disentangle the spectrum of the system, and performed an orbital, polarimetric, and spectral analysis, as well as an analysis of the wind-wind collision region. The true masses of the binary components turned out to be significantly lower than suggested, impacting our understanding of the initial mass function and stellar evolution at low metallicity (Chapter 5). Finally, all known WR binaries in the Small Magellanic Cloud (SMC) were analyzed. Although it was theoretical predicted that virtually all WR stars in the SMC should be formed via mass-transfer in binaries, we find that binarity was not important for the formation of the known WR stars in the SMC, implying a strong discrepancy between theory and observations (Chapter 6).}, language = {en} } @phdthesis{Schuermann2017, author = {Sch{\"u}rmann, Robin Mathis}, title = {Interaction of the potential DNA-radiosensitizer 8-bromoadenine with free and plasmonically generated electrons}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-407017}, school = {Universit{\"a}t Potsdam}, pages = {xi, 120}, year = {2017}, abstract = {In Germany more than 200.000 persons die of cancer every year, which makes it the second most common cause of death. Chemotherapy and radiation therapy are often combined to exploit a supra-additive effect, as some chemotherapeutic agents like halogenated nucleobases sensitize the cancerous tissue to radiation. The radiosensitizing action of certain therapeutic agents can be at least partly assigned to their interaction with secondary low energy electrons (LEEs) that are generated along the track of the ionizing radiation. In the therapy of cancer DNA is an important target, as severe DNA damage like double strand breaks induce the cell death. As there is only a limited number of radiosensitizing agents in clinical practice, which are often strongly cytotoxic, it would be beneficial to get a deeper understanding of the interaction of less toxic potential radiosensitizers with secondary reactive species like LEEs. Beyond that LEEs can be generated by laser illuminated nanoparticles that are applied in photothermal therapy (PTT) of cancer, which is an attempt to treat cancer by an increase of temperature in the cells. However, the application of halogenated nucleobases in PTT has not been taken into account so far. In this thesis the interaction of the potential radiosensitizer 8-bromoadenine (8BrA) with LEEs was studied. In a first step the dissociative electron attachment (DEA) in the gas phase was studied in a crossed electron-molecular beam setup. The main fragmentation pathway was revealed as the cleavage of the C-Br bond. The formation of a stable parent anion was observed for electron energies around 0 eV. Furthermore, DNA origami nanostructures were used as platformed to determine electron induced strand break cross sections of 8BrA sensitized oligonucleotides and the corresponding nonsensitized sequence as a function of the electron energy. In this way the influence of the DEA resonances observed for the free molecules on the DNA strand breaks was examined. As the surrounding medium influences the DEA, pulsed laser illuminated gold nanoparticles (AuNPs) were used as a nanoscale electron source in an aqueous environment. The dissociation of brominated and native nucleobases was tracked with UV-Vis absorption spectroscopy and the generated fragments were identified with surface enhanced Raman scattering (SERS). Beside the electron induced damage, nucleobase analogues are decomposed in the vicinity of the laser illuminatednanoparticles due to the high temperatures. In order to get a deeper understanding of the different dissociation mechanisms, the thermal decomposition of the nucleobases in these systems was studied and the influence of the adsorption kinetics of the molecules was elucidated. In addition to the pulsed laser experiments, a dissociative electron transfer from plasmonically generated "hot electrons" to 8BrA was observed under low energy continuous wave laser illumination and tracked with SERS. The reaction was studied on AgNPs and AuNPs as a function of the laser intensity and wavelength. On dried samples the dissociation of the molecule was described by fractal like kinetics. In solution, the dissociative electron transfer was observed as well. It turned out that the timescale of the reaction rates were slightly below typical integration times of Raman spectra. In consequence such reactions need to be taken into account in the interpretation of SERS spectra of electrophilic molecules. The findings in this thesis help to understand the interaction of brominated nucleobases with plasmonically generated electrons and free electrons. This might help to evaluate the potential radiosensitizing action of such molecules in cancer radiation therapy and PTT.}, language = {en} } @phdthesis{Schuster2017, author = {Schuster, Isabell}, title = {Prevalence and Predictors of Sexual Aggression Victimization and Perpetration in Chile and Turkey}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-413897}, school = {Universit{\"a}t Potsdam}, pages = {285}, year = {2017}, abstract = {Background: Although sexual aggression is recognized as a serious issue worldwide, the current knowledge base is primarily built on evidence from Western countries, particularly the U.S. For the present doctoral research, Chile and Turkey were selected based on theoretical considerations to examine the prevalence as well as predictors of sexual aggression victimization and perpetration. The first aim of this research project was to systematically review the available evidence provided by past studies on this topic within each country. The second aim was to empirically study the prevalence of experiencing and engaging in sexual aggression since the age of consent among college students in Chile and Turkey. The third aim was to conduct cross-cultural analyses examining pathways to victimization and perpetration based on a two-wave longitudinal design. Methods: This research adopted a gender-inclusive approach by considering men and women in both victim and perpetrator roles. For the systematic reviews, multiple-stage literature searches were performed, and based on a predefined set of eligibility criteria, 28 studies in Chile and 56 studies in Turkey were identified for inclusion. A two-wave longitudinal study was conducted to examine the prevalence and predictors of sexual aggression among male and female college students in Chile and Turkey. Self-reports of victimization and perpetration were assessed with a Chilean Spanish or Turkish version of the Sexual Aggression and Victimization Scale. Two path models were conceptualized in which participants' risky sexual scripts for consensual sex, risky sexual behavior, sexual self-esteem, sexual assertiveness, and religiosity were assessed at T1 and used as predictors of sexual aggression victimization and perpetration at T2 in the following 12 months, mediated through past victimization or perpetration, respectively. The models differed in that sexual assertiveness was expected to serve different functions for victimization (refusal assertiveness negatively linked to victimization) and perpetration (initiation assertiveness positively linked to perpetration). Results: Both systematic reviews revealed that victimization was addressed by all included studies, but data on perpetration was severely limited. A great heterogeneity not only in victimization rates but also in predictors was found, which may be attributed to a lack of conceptual and methodological consistency across studies. The empirical analysis of the prevalence of sexual aggression in Chile revealed a victimization rate of 51.9\% for women and 48.0\% for men, and a perpetration rate of 26.8\% for men and 16.5\% for women. In the Turkish original data, victimization was reported by 77.6\% of women and 65.5\% of men, whereas, again, lower rates were found for perpetration, with 28.9\% of men and 14.2\% of women reporting at least one incident. The cross-cultural analyses showed, as expected, that risky sexual scripts informed risky sexual behavior, and thereby indirectly increased the likelihood of victimization and perpetration at T2 in both samples. More risky sexual scripts were also linked to lower levels of refusal assertiveness in both samples, indirectly increasing the vulnerability to victimization at T2. High sexual self-esteem decreased the probability of victimization at T2 through higher refusal assertiveness as well as through less risky sexual behavior also in both samples, whereas it increased the odds of perpetration at T2 via higher initiation assertiveness in the Turkish sample only. Furthermore, high religiosity decreased the odds of perpetration and victimization at T2 through less risky sexual scripts and less risky sexual behavior in both samples. It reduced the vulnerability to victimization through less risky sexual scripts and higher refusal assertiveness in the Chilean sample only. In the Turkish sample only, it increased the odds of perpetration and victimization through lower sexual self-esteem. Conclusions: The findings showed that sexual aggression is a widespread problem in both Chile and Turkey, contributing cross-cultural evidence to the international knowledge base and indicating the clear need for implementing policy measures and prevention strategies in each country. Based on the results of the prospective analyses, concrete implications for intervention efforts are discussed.}, language = {en} } @phdthesis{Schunack2017, author = {Schunack, Silke}, title = {Processing of non-canonical word orders in an L2}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-103750}, school = {Universit{\"a}t Potsdam}, pages = {xvii, 443 Seiten}, year = {2017}, abstract = {This thesis investigates the processing of non-canonical word orders and whether non-canonical orders involving object topicalizations, midfield scrambling and particle verbs are treated the same by native (L1) and non-native (L2) speakers. The two languages investigated are Norwegian and German. 32 L1 Norwegian and 32 L1 German advanced learners of Norwegian were tested in two experiments on object topicalization in Norwegian. The results from the online self-paced reading task and the offline agent identification task show that both groups are able to identify the non-canonical word order and show a facilitatory effect of animate subjects in their reanalysis. Similarly high error rates in the agent identification task suggest that globally unambiguous object topicalizations are a challenging structure for L1 and L2 speakers alike. The same participants were also tested in two experiments on particle placement in Norwegian, again using a self-paced reading task, this time combined with an acceptability rating task. In the acceptability rating L1 and L2 speakers show the same preference for the verb-adjacent placement of the particle over the non-adjacent placement after the direct object. However, this preference for adjacency is only found in the L1 group during online processing, whereas the L2 group shows no preference for either order. Another set of experiments tested 33 L1 German and 39 L1 Slavic advanced learners of German on object scrambling in ditransitive clauses in German. Non-native speakers accept both object orders and show neither a preference for either order nor a processing advantage for the canonical order. The L1 group, in contrast, shows a small, but significant preference for the canonical dative-first order in the judgment and the reading task. The same participants were also tested in two experiments on the application of the split rule in German particle verbs. Advanced L2 speakers of German are able to identify particle verbs and can apply the split rule in V2 contexts in an acceptability judgment task in the same way as L1 speakers. However, unlike the L1 group, the L2 group is not sensitive to the grammaticality manipulation during online processing. They seem to be sensitive to the additional lexical information provided by the particle, but are unable to relate the split particle to the preceding verb and recognize the ungrammaticality in non-V2 contexts. Taken together, my findings suggest that non-canonical word orders are not per se more difficult to identify for L2 speakers than L1 speakers and can trigger the same reanalysis processes as in L1 speakers. I argue that L2 speakers' ability to identify a non-canonical word order depends on how the non-canonicity is signaled (case marking vs. surface word order), on the constituents involved (identical vs. different word types), and on the impact of the word order change on sentence meaning. Non-canonical word orders that are signaled by morphological case marking and cause no change to the sentence's content are hard to detect for L2 speakers.}, language = {en} } @phdthesis{Schumacher2017, author = {Schumacher, Kinga}, title = {Hybride semantische Suche - eine Kombination aus Fakten- und Dokumentretrieval}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-405973}, school = {Universit{\"a}t Potsdam}, pages = {vii, 187}, year = {2017}, abstract = {Das Thema der vorliegenden Arbeit ist die semantische Suche im Kontext heutiger Informationsmanagementsysteme. Zu diesen Systemen z{\"a}hlen Intranets, Web 3.0-Anwendungen sowie viele Webportale, die Informationen in heterogenen Formaten und Strukturen beinhalten. Auf diesen befinden sich einerseits Daten in strukturierter Form und andererseits Dokumente, die inhaltlich mit diesen Daten in Beziehung stehen. Diese Dokumente sind jedoch in der Regel nur teilweise strukturiert oder vollst{\"a}ndig unstrukturiert. So beschreiben beispielsweise Reiseportale durch strukturierte Daten den Zeitraum, das Reiseziel, den Preis einer Reise und geben in unstrukturierter Form weitere Informationen, wie Beschreibungen zum Hotel, Zielort, Ausflugsziele an. Der Fokus heutiger semantischer Suchmaschinen liegt auf dem Finden von Wissen entweder in strukturierter Form, auch Faktensuche genannt, oder in semi- bzw. unstrukturierter Form, was {\"u}blicherweise als semantische Dokumentensuche bezeichnet wird. Einige wenige Suchmaschinen versuchen die L{\"u}cke zwischen diesen beiden Ans{\"a}tzen zu schließen. Diese durchsuchen zwar gleichzeitig strukturierte sowie unstrukturierte Daten, werten diese jedoch entweder weitgehend voneinander unabh{\"a}ngig aus oder schr{\"a}nken die Suchm{\"o}glichkeiten stark ein, indem sie beispielsweise nur bestimmte Fragemuster unterst{\"u}tzen. Hierdurch werden die im System verf{\"u}gbaren Informationen nicht ausgesch{\"o}pft und gleichzeitig unterbunden, dass Zusammenh{\"a}nge zwischen einzelnen Inhalten der jeweiligen Informationssysteme und sich erg{\"a}nzende Informationen den Benutzer erreichen.
 Um diese L{\"u}cke zu schließen, wurde in der vorliegenden Arbeit ein neuer hybrider semantischer Suchansatz entwickelt und untersucht, der strukturierte und semi- bzw. unstrukturierte Inhalte w{\"a}hrend des gesamten Suchprozesses kombiniert. Durch diesen Ansatz werden nicht nur sowohl Fakten als auch Dokumente gefunden, es werden auch Zusammenh{\"a}nge, die zwischen den unterschiedlich strukturierten Daten bestehen, in jeder Phase der Suche genutzt und fließen in die Suchergebnisse mit ein. Liegt die Antwort zu einer Suchanfrage nicht vollst{\"a}ndig strukturiert, in Form von Fakten, oder unstrukturiert, in Form von Dokumenten vor, so liefert dieser Ansatz eine Kombination der beiden. Die Ber{\"u}cksichtigung von unterschiedlich Inhalten w{\"a}hrend des gesamten Suchprozesses stellt jedoch besondere Herausforderungen an die Suchmaschine. Diese muss in der Lage sein, Fakten und Dokumente in Abh{\"a}ngigkeit voneinander zu durchsuchen, sie zu kombinieren sowie die unterschiedlich strukturierten Ergebnisse in eine geeignete Rangordnung zu bringen. Weiterhin darf die Komplexit{\"a}t der Daten nicht an die Endnutzer weitergereicht werden. Die Darstellung der Inhalte muss vielmehr sowohl bei der Anfragestellung als auch bei der Darbietung der Ergebnisse verst{\"a}ndlich und leicht interpretierbar sein. Die zentrale Fragestellung der Arbeit ist, ob ein hybrider Ansatz auf einer vorgegebenen Datenbasis die Suchanfragen besser beantworten kann als die semantische Dokumentensuche und die Faktensuche f{\"u}r sich genommen, bzw. als eine Suche die diese Ans{\"a}tze im Rahmen des Suchprozesses nicht kombiniert. Die durchgef{\"u}hrten Evaluierungen aus System- und aus Benutzersicht zeigen, dass die im Rahmen der Arbeit entwickelte hybride semantische Suchl{\"o}sung durch die Kombination von strukturierten und unstrukturierten Inhalten im Suchprozess bessere Antworten liefert als die oben genannten Verfahren und somit Vorteile gegen{\"u}ber bisherigen Ans{\"a}tzen bietet. Eine Befragung von Benutzern macht deutlich, dass die hybride semantische Suche als verst{\"a}ndlich empfunden und f{\"u}r heterogen strukturierte Datenmengen bevorzugt wird.}, language = {de} } @phdthesis{Schulze2017, author = {Schulze, Nicole}, title = {Neue Templatphasen zur anisotropen Goldnanopartikelherstellung durch den Einsatz strukturbildender Polymere}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-409515}, school = {Universit{\"a}t Potsdam}, pages = {VI, 117, xv}, year = {2017}, abstract = {Ziel der vorliegenden Arbeit war die Synthese und Charakterisierung von anisotropen Goldnanopartikeln in einer geeigneten Polyelektrolyt-modifizierten Templatphase. Der Mittelpunkt bildet dabei die Auswahl einer geeigneten Templatphase, zur Synthese von einheitlichen und reproduzierbaren anisotropen Goldnanopartikeln mit den daraus resultierenden besonderen Eigenschaften. Bei der Synthese der anisotropen Goldnanopartikeln lag der Fokus in der Verwendung von Vesikeln als Templatphase, wobei hier der Einfluss unterschiedlicher strukturbildender Polymere (stark alternierende Maleamid-Copolymere PalH, PalPh, PalPhCarb und PalPhBisCarb mit verschiedener Konformation) und Tenside (SDS, AOT - anionische Tenside) bei verschiedenen Synthese- und Abtrennungsbedingungen untersucht werden sollte. Im ersten Teil der Arbeit konnte gezeigt werden, dass PalPhBisCarb bei einem pH-Wert von 9 die Bedingungen eines R{\"o}hrenbildners f{\"u}r eine morphologische Transformation von einer vesikul{\"a}ren Phase in eine r{\"o}hrenf{\"o}rmige Netzwerkstruktur erf{\"u}llt und somit als Templatphase zur formgesteuerten Bildung von Nanopartikeln genutzt werden kann. Im zweiten Teil der Arbeit wurde dargelegt, dass die Templatphase PalPhBisCarb (pH-Wert von 9, Konzentration von 0,01 wt.\%) mit AOT als Tensid und PL90G als Phospholipid (im Verh{\"a}ltnis 1:1) die effektivste Wahl einer Templatphase f{\"u}r die Bildung von anisotropen Strukturen in einem einstufigen Prozess darstellt. Bei einer konstanten Synthesetemperatur von 45 °C wurden die besten Ergebnisse bei einer Goldchloridkonzentration von 2 mM, einem Gold-Templat-Verh{\"a}ltnis von 3:1 und einer Synthesezeit von 30 Minuten erzielt. Ausbeute an anisotropen Strukturen lag bei 52 \% (Anteil an dreieckigen Nanopl{\"a}ttchen von 19 \%). Durch Erh{\"o}hung der Synthesetemperatur konnte die Ausbeute auf 56 \% (29 \%) erh{\"o}ht werden. Im dritten Teil konnte durch zeitabh{\"a}ngige Untersuchungen gezeigt werden, dass bei Vorhandensein von PalPhBisCarb die Bildung der energetisch nicht bevorzugten Pl{\"a}ttchen-Strukturen bei Raumtemperatur initiiert wird und bei 45 °C ein Optimum annimmt. Kintetische Untersuchungen haben gezeigt, dass die Bildung dreieckiger Nanopl{\"a}ttchen bei schrittweiser Zugabe der Goldchlorid-Pr{\"a}kursorl{\"o}sung zur PalPhBisCarb enthaltenden Templatphase durch die Dosierrate der vesikul{\"a}ren Templatphase gesteuert werden kann. In umgekehrter Weise findet bei Zugabe der Templatphase zur Goldchlorid-Pr{\"a}kursorl{\"o}sung bei 45 °C ein {\"a}hnlicher, kinetisch gesteuerter Prozess der Bildung von Nanodreiecken statt mit einer maximalen Ausbeute dreieckigen Nanopl{\"a}ttchen von 29 \%. Im letzten Kapitel erfolgten erste Versuche zur Abtrennung dreieckiger Nanopl{\"a}ttchen von den {\"u}brigen Geometrien der gemischten Nanopartikell{\"o}sung mittels tensidinduzierter Verarmungsf{\"a}llung. Bei Verwendung von AOT mit einer Konzentration von 0,015 M wurde eine Ausbeute an Nanopl{\"a}ttchen von 99 \%, wovon 72 \% dreieckiger Geometrien hatten, erreicht.}, language = {de} } @phdthesis{Schmierer2017, author = {Schmierer, Christoph}, title = {Technologietransfer und Spillovereffekte ausl{\"a}ndischer Tochterunternehmen in Entwicklungs- und Schwellenl{\"a}ndern}, series = {Potsdam Economic Studies}, journal = {Potsdam Economic Studies}, number = {6}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, isbn = {978-3-86956-398-5}, issn = {2196-8691}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-103988}, school = {Universit{\"a}t Potsdam}, year = {2017}, abstract = {F{\"u}r den Industrialisierungsprozess von Entwicklungs- und Schwellenl{\"a}ndern haben ausl{\"a}ndische Direktinvestitionen (ADI) eine wichtige Funktion. Sie k{\"o}nnen zum einen zu einer Erh{\"o}hung des industriellen Output des Ziellandes f{\"u}hren und zum anderen als Tr{\"a}ger von technologischem Wissen fungieren. Neues Wissen kann den Empf{\"a}ngerl{\"a}ndern der ADI durch Spillovereffekte und Technologietransfers ausl{\"a}ndischer Tochterunternehmen zufließen. Diese Arbeit soll Antworten auf die Fragen geben, durch welche Mechanismen Spillovereffekte und Technologietransfers ausgel{\"o}st werden und wie Entwicklungs- und Schwellenl{\"a}ndern diesen Wissenszufluss zur Beschleunigung ihres Industrialisierungsprozesses einsetzen k{\"o}nnen. Hierf{\"u}r wird ein Konzept zur F{\"o}rderung von Spillovereffekten entwickelt. Weiterhin wird ein theoretisches Modell entwickelt, in dem der Technologietransfer ausl{\"a}ndischer Exportplattformen erstmals in Abh{\"a}ngigkeit des Anteils der Vorprodukte, die im Gastland nachgefragt werden, untersucht. In den Fallstudien Irland und Malaysia werden die Ergebnisse des theoretischen Modells sowie des entwickelten Konzepts illustriert.}, language = {de} } @phdthesis{Schmidt2017, author = {Schmidt, Silke Regina}, title = {Analyzing lakes in the time frequency domain}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-406955}, school = {Universit{\"a}t Potsdam}, pages = {VIII, 126}, year = {2017}, abstract = {The central aim of this thesis is to demonstrate the benefits of innovative frequency-based methods to better explain the variability observed in lake ecosystems. Freshwater ecosystems may be the most threatened part of the hydrosphere. Lake ecosystems are particularly sensitive to changes in climate and land use because they integrate disturbances across their entire catchment. This makes understanding the dynamics of lake ecosystems an intriguing and important research priority. This thesis adds new findings to the baseline knowledge regarding variability in lake ecosystems. It provides a literature-based, data-driven and methodological framework for the investigation of variability and patterns in environmental parameters in the time frequency domain. Observational data often show considerable variability in the environmental parameters of lake ecosystems. This variability is mostly driven by a plethora of periodic and stochastic processes inside and outside the ecosystems. These run in parallel and may operate at vastly different time scales, ranging from seconds to decades. In measured data, all of these signals are superimposed, and dominant processes may obscure the signals of other processes, particularly when analyzing mean values over long time scales. Dominant signals are often caused by phenomena at long time scales like seasonal cycles, and most of these are well understood in the limnological literature. The variability injected by biological, chemical and physical processes operating at smaller time scales is less well understood. However, variability affects the state and health of lake ecosystems at all time scales. Besides measuring time series at sufficiently high temporal resolution, the investigation of the full spectrum of variability requires innovative methods of analysis. Analyzing observational data in the time frequency domain allows to identify variability at different time scales and facilitates their attribution to specific processes. The merit of this approach is subsequently demonstrated in three case studies. The first study uses a conceptual analysis to demonstrate the importance of time scales for the detection of ecosystem responses to climate change. These responses often occur during critical time windows in the year, may exhibit a time lag and can be driven by the exceedance of thresholds in their drivers. This can only be detected if the temporal resolution of the data is high enough. The second study applies Fast Fourier Transform spectral analysis to two decades of daily water temperature measurements to show how temporal and spatial scales of water temperature variability can serve as an indicator for mixing in a shallow, polymictic lake. The final study uses wavelet coherence as a diagnostic tool for limnology on a multivariate high-frequency data set recorded between the onset of ice cover and a cyanobacteria summer bloom in the year 2009 in a polymictic lake. Synchronicities among limnological and meteorological time series in narrow frequency bands were used to identify and disentangle prevailing limnological processes. Beyond the novel empirical findings reported in the three case studies, this thesis aims to more generally be of interest to researchers dealing with now increasingly available time series data at high temporal resolution. A set of innovative methods to attribute patterns to processes, their drivers and constraints is provided to help make more efficient use of this kind of data.}, language = {en} } @phdthesis{Schmidt2017, author = {Schmidt, Katja}, title = {Assessing, testing, and implementing socio-cultural valuation methods to operationalise ecosystem services in land use management}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-411049}, school = {Universit{\"a}t Potsdam}, pages = {165}, year = {2017}, abstract = {Ecosystem services (ESs) are defined as the contributions that ecosystems make to human wellbeing and are increasingly being used as an approach to explore the importance of ecosystems for humans through their valuation. Although value plurality has been recognised long before the mainstreaming of ESs research, socio-cultural valuation is still underrepresented in ESs assessments. It is the central goal of this PhD dissertation to explore the ability of socio-cultural valuation methods for the operationalisation of ESs research in land management. To address this, I formulated three research objectives that are briefly outlined below and relate to the three studies conducted during this dissertation. The first objective relates to the assessment of the current role of socio-cultural valuation in ESs research. Human values are central to ESs research yet non-monetary socio-cultural valuation methods have been found underrepresented in the field of ESs science. In regard to the unbalanced consideration of value domains and conceptual uncertainties, I perform a systematic literature review aiming to answer the research question: To what extent have socio-cultural values been addressed in ESs assessments. The second objective aims to test socio-cultural valuation methods of ESs and their relevance for land use preferences by exploring their methodological opportunities and limitations. Socio-cultural valuation methods have only recently become a focus in ESs research and therefore bear various uncertainties in regard to their methodological implications. To overcome these uncertainties, I analysed responses to a visitor survey. The research questions related to the second objective were: What are the implications of different valuation methods for ESs values? To what extent are land use preferences explained by socio-cultural values of ESs? The third objective addressed in this dissertation is the implementation of ESs research into land management through socio-cultural valuation. Though it is emphasised that the ESs approach can assist decision making, there is little empirical evidence of the effect of ESs knowledge on land management. I proposed a way to implement transdisciplinary, spatially explicit research on ESs by answering the following research questions: Which landscape features underpinning ESs supply are considered in land management? How can participatory approaches accounting for ESs be operationalised in land management? The empirical research resulted in five main findings that provide answers to the research questions. First, this dissertation provides evidence that socio-cultural values are an integral part of ESs research. I found that they can be assessed for provisioning, regulating, and cultural services though they are linked to cultural services to a greater degree. Socio-cultural values have been assessed by monetary and non-monetary methods and their assessment is effectively facilitated by stakeholder participation. Second, I found that different methods of socio-cultural valuation revealed different information. Whereas rating revealed a general value of ESs, weighting was found more suitable to identify priorities across ESs. Value intentions likewise differed in the distribution of values, generally implying a higher value for others than for respondents themselves. Third, I showed that ESs values were distributed similarly across groups with differing land use preferences. Thus, I provided empirical evidence that ESs values and landscape values should not be used interchangeably. Fourth, I showed which landscape features important for ESs supply in a Scottish regional park are not sufficiently accounted for in the current management strategy. This knowledge is useful for the identification of priority sites for land management. Finally, I provide an approach to explore how ESs knowledge elicited by participatory mapping can be operationalised in land management. I demonstrate how stakeholder knowledge and values can be used for the identification of ESs hotspots and how these hotspots can be compared to current management priorities. This dissertation helps to bridge current gaps of ESs science by advancing the understanding of the current role of socio-cultural values in ESs research, testing different methods and their relevance for land use preferences, and implementing ESs knowledge into land management. If and to what extent ESs and their values are implemented into ecosystem management is mainly the choice of the management. An advanced understanding of socio-cultural valuation methods contributes to the normative basis of this management, while the proposal for the implementation of ESs in land management presents a practical approach of how to transfer this type of knowledge into practice. The proposed methods for socio-cultural valuation can support guiding land management towards a balanced consideration of ESs and conservation goals.}, language = {en} }