@phdthesis{Kerutt2019, author = {Kerutt, Josephine Victoria}, title = {The high-redshift voyage of Lyman alpha and Lyman continuum emission as told by MUSE}, doi = {10.25932/publishup-47881}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-478816}, school = {Universit{\"a}t Potsdam}, pages = {152}, year = {2019}, abstract = {Most of the matter in the universe consists of hydrogen. The hydrogen in the intergalactic medium (IGM), the matter between the galaxies, underwent a change of its ionisation state at the epoch of reionisation, at a redshift roughly between 6>z>10, or ~10^8 years after the Big Bang. At this time, the mostly neutral hydrogen in the IGM was ionised but the source of the responsible hydrogen ionising emission remains unclear. In this thesis I discuss the most likely candidates for the emission of this ionising radiation, which are a type of galaxy called Lyman alpha emitters (LAEs). As implied by their name, they emit Lyman alpha radiation, produced after a hydrogen atom has been ionised and recombines with a free electron. The ionising radiation itself (also called Lyman continuum emission) which is needed for this process inside the LAEs could also be responsible for ionising the IGM around those galaxies at the epoch of reionisation, given that enough Lyman continuum escapes. Through this mechanism, Lyman alpha and Lyman continuum radiation are closely linked and are both studied to better understand the properties of high redshift galaxies and the reionisation state of the universe. Before I can analyse their Lyman alpha emission lines and the escape of Lyman continuum emission from them, the first step is the detection and correct classification of LAEs in integral field spectroscopic data, specifically taken with the Multi-Unit Spectroscopic Explorer (MUSE). After detecting emission line objects in the MUSE data, the task of classifying them and determining their redshift is performed with the graphical user interface QtClassify, which I developed during the work on this thesis. It uses the strength of the combination of spectroscopic and photometric information that integral field spectroscopy offers to enable the user to quickly identify the nature of the detected emission lines. The reliable classification of LAEs and determination of their redshifts is a crucial first step towards an analysis of their properties. Through radiative transfer processes, the properties of the neutral hydrogen clouds in and around LAEs are imprinted on the shape of the Lyman alpha line. Thus after identifying the LAEs in the MUSE data, I analyse the properties of the Lyman alpha emission line, such as the equivalent width (EW) distribution, the asymmetry and width of the line as well as the double peak fraction. I challenge the common method of displaying EW distributions as histograms without taking the limits of the survey into account and construct a more independent EW distribution function that better reflects the properties of the underlying population of galaxies. I illustrate this by comparing the fraction of high EW objects between the two surveys MUSE-Wide and MUSE-Deep, both consisting of MUSE pointings (each with the size of one square arcminute) of different depths. In the 60 MUSE-Wide fields of one hour exposure time I find a fraction of objects with extreme EWs above EW_0>240A of ~20\%, while in the MUSE-Deep fields (9 fields with an exposure time of 10 hours and one with an exposure time of 31 hours) I find a fraction of only ~1\%, which is due to the differences in the limiting line flux of the surveys. The highest EW I measure is EW_0 = 600.63 +- 110A, which hints at an unusual underlying stellar population, possibly with a very low metallicity. With the knowledge of the redshifts and positions of the LAEs detected in the MUSE-Wide survey, I also look for Lyman continuum emission coming from these galaxies and analyse the connection between Lyman continuum emission and Lyman alpha emission. I use ancillary Hubble Space Telescope (HST) broadband photometry in the bands that contain the Lyman continuum and find six Lyman continuum leaker candidates. To test whether the Lyman continuum emission of LAEs is coming only from those individual objects or the whole population, I select LAEs that are most promising for the detection of Lyman continuum emission, based on their rest-frame UV continuum and Lyman alpha line shape properties. After this selection, I stack the broadband data of the resulting sample and detect a signal in Lyman continuum with a significance of S/N = 5.5, pointing towards a Lyman continuum escape fraction of ~80\%. If the signal is reliable, it strongly favours LAEs as the providers of the hydrogen ionising emission at the epoch of reionisation and beyond.}, language = {en} } @article{PornsawadSapsakulBoeckmann2019, author = {Pornsawad, Pornsarp and Sapsakul, Nantawan and B{\"o}ckmann, Christine}, title = {A modified asymptotical regularization of nonlinear ill-posed problems}, series = {Mathematics}, volume = {7}, journal = {Mathematics}, edition = {5}, publisher = {MDPI}, address = {Basel, Schweiz}, issn = {2227-7390}, doi = {10.3390/math7050419}, pages = {19}, year = {2019}, abstract = {In this paper, we investigate the continuous version of modified iterative Runge-Kutta-type methods for nonlinear inverse ill-posed problems proposed in a previous work. The convergence analysis is proved under the tangential cone condition, a modified discrepancy principle, i.e., the stopping time T is a solution of ∥𝐹(𝑥𝛿(𝑇))-𝑦𝛿∥=𝜏𝛿+ for some 𝛿+>𝛿, and an appropriate source condition. We yield the optimal rate of convergence.}, language = {en} } @phdthesis{Beamish2019, author = {Beamish, Alison Leslie}, title = {Hyperspectral remote sensing of the spatial and temporal heterogeneity of low Arctic vegetation}, doi = {10.25932/publishup-42592}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-425922}, school = {Universit{\"a}t Potsdam}, pages = {v, 102}, year = {2019}, abstract = {Arctic tundra ecosystems are experiencing warming twice the global average and Arctic vegetation is responding in complex and heterogeneous ways. Shifting productivity, growth, species composition, and phenology at local and regional scales have implications for ecosystem functioning as well as the global carbon and energy balance. Optical remote sensing is an effective tool for monitoring ecosystem functioning in this remote biome. However, limited field-based spectral characterization of the spatial and temporal heterogeneity limits the accuracy of quantitative optical remote sensing at landscape scales. To address this research gap and support current and future satellite missions, three central research questions were posed: • Does canopy-level spectral variability differ between dominant low Arctic vegetation communities and does this variability change between major phenological phases? • How does canopy-level vegetation colour images recorded with high and low spectral resolution devices relate to phenological changes in leaf-level photosynthetic pigment concentrations? • How does spatial aggregation of high spectral resolution data from the ground to satellite scale influence low Arctic tundra vegetation signatures and thereby what is the potential of upcoming hyperspectral spaceborne systems for low Arctic vegetation characterization? To answer these questions a unique and detailed database was assembled. Field-based canopy-level spectral reflectance measurements, nadir digital photographs, and photosynthetic pigment concentrations of dominant low Arctic vegetation communities were acquired at three major phenological phases representing early, peak and late season. Data were collected in 2015 and 2016 in the Toolik Lake Research Natural Area located in north central Alaska on the North Slope of the Brooks Range. In addition to field data an aerial AISA hyperspectral image was acquired in the late season of 2016. Simulations of broadband Sentinel-2 and hyperspectral Environmental and Mapping Analysis Program (EnMAP) satellite reflectance spectra from ground-based reflectance spectra as well as simulations of EnMAP imagery from aerial hyperspectral imagery were also obtained. Results showed that canopy-level spectral variability within and between vegetation communities differed by phenological phase. The late season was identified as the most discriminative for identifying many dominant vegetation communities using both ground-based and simulated hyperspectral reflectance spectra. This was due to an overall reduction in spectral variability and comparable or greater differences in spectral reflectance between vegetation communities in the visible near infrared spectrum. Red, green, and blue (RGB) indices extracted from nadir digital photographs and pigment-driven vegetation indices extracted from ground-based spectral measurements showed strong significant relationships. RGB indices also showed moderate relationships with chlorophyll and carotenoid pigment concentrations. The observed relationships with the broadband RGB channels of the digital camera indicate that vegetation colour strongly influences the response of pigment-driven spectral indices and digital cameras can track the seasonal development and degradation of photosynthetic pigments. Spatial aggregation of hyperspectral data from the ground to airborne, to simulated satel-lite scale was influenced by non-photosynthetic components as demonstrated by the distinct shift of the red edge to shorter wavelengths. Correspondence between spectral reflectance at the three scales was highest in the red spectrum and lowest in the near infra-red. By artificially mixing litter spectra at different proportions to ground-based spectra, correspondence with aerial and satellite spectra increased. Greater proportions of litter were required to achieve correspondence at the satellite scale. Overall this thesis found that integrating multiple temporal, spectral, and spatial data is necessary to monitor the complexity and heterogeneity of Arctic tundra ecosystems. The identification of spectrally similar vegetation communities can be optimized using non-peak season hyperspectral data leading to more detailed identification of vegetation communities. The results also highlight the power of vegetation colour to link ground-based and satellite data. Finally, a detailed characterization non-photosynthetic ecosystem components is crucial for accurate interpretation of vegetation signals at landscape scales.}, language = {en} } @misc{KotthoffLisecSchwerdtleetal.2019, author = {Kotthoff, Lisa and Lisec, Jan and Schwerdtle, Tanja and Koch, Matthias}, title = {Prediction of transformation products of monensin by electrochemistry compared to microsomal assay and hydrolysis}, series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {1340}, issn = {1866-8372}, doi = {10.25932/publishup-47326}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-473262}, pages = {12}, year = {2019}, abstract = {The knowledge of transformation pathways and identification of transformation products (TPs) of veterinary drugs is important for animal health, food, and environmental matters. The active agent Monensin (MON) belongs to the ionophore antibiotics and is widely used as a veterinary drug against coccidiosis in broiler farming. However, no electrochemically (EC) generated TPs of MON have been described so far. In this study, the online coupling of EC and mass spectrometry (MS) was used for the generation of oxidative TPs. EC-conditions were optimized with respect to working electrode material, solvent, modifier, and potential polarity. Subsequent LC/HRMS (liquid+ chromatography/high resolution mass spectrometry) and MS/MS experiments were performed to identify the structures of derived TPs by a suspected target analysis. The obtained EC-results were compared to TPs observed in metabolism tests with microsomes and hydrolysis experiments of MON. Five previously undescribed TPs of MON were identified in our EC/MS based study and one TP, which was already known from literature and found by a microsomal assay, could be confirmed. Two and three further TPs were found as products in microsomal tests and following hydrolysis, respectively. We found decarboxylation, O-demethylation and acid-catalyzed ring-opening reactions to be the major mechanisms of MON transformation}, language = {en} } @article{KotthoffLisecSchwerdtleetal.2019, author = {Kotthoff, Lisa and Lisec, Jan and Schwerdtle, Tanja and Koch, Matthias}, title = {Prediction of transformation products of monensin by electrochemistry compared to microsomal assay and hydrolysis}, series = {Molecules}, volume = {24}, journal = {Molecules}, number = {15}, publisher = {MDPI}, address = {Basel}, issn = {1420-3049}, doi = {10.3390/molecules24152732}, pages = {12}, year = {2019}, abstract = {The knowledge of transformation pathways and identification of transformation products (TPs) of veterinary drugs is important for animal health, food, and environmental matters. The active agent Monensin (MON) belongs to the ionophore antibiotics and is widely used as a veterinary drug against coccidiosis in broiler farming. However, no electrochemically (EC) generated TPs of MON have been described so far. In this study, the online coupling of EC and mass spectrometry (MS) was used for the generation of oxidative TPs. EC-conditions were optimized with respect to working electrode material, solvent, modifier, and potential polarity. Subsequent LC/HRMS (liquid chromatography/high resolution mass spectrometry) and MS/MS experiments were performed to identify the structures of derived TPs by a suspected target analysis. The obtained EC-results were compared to TPs observed in metabolism tests with microsomes and hydrolysis experiments of MON. Five previously undescribed TPs of MON were identified in our EC/MS based study and one TP, which was already known from literature and found by a microsomal assay, could be confirmed. Two and three further TPs were found as products in microsomal tests and following hydrolysis, respectively. We found decarboxylation, O-demethylation and acid-catalyzed ring-opening reactions to be the major mechanisms of MON transformation.}, language = {en} } @techreport{Nastansky2019, type = {Working Paper}, author = {Nastansky, Andreas}, title = {Topologische Datenanalyse}, series = {Statistische Diskussionsbeitr{\"a}ge}, journal = {Statistische Diskussionsbeitr{\"a}ge}, number = {53}, doi = {10.25932/publishup-43142}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-431420}, pages = {38}, year = {2019}, abstract = {Bei der Analyse von h{\"o}herdimensionalen Daten kann deren Gestalt wichtige Informationen {\"u}ber den Datensatz liefern. Bei einer gegebenen Punktwolke, die aus einem unbekannten topologischen Raum ausgew{\"a}hlt wurde, versucht die Topologische Datenanalyse (TDA) den urspr{\"u}nglichen Raum zu rekonstruieren. Dieser Beitrag soll eine Einf{\"u}hrung in die Topologische Datenanalyse geben und konzentriert sich dabei auf zwei wichtige Aspekte: die Persistente Homologie und den Mapper. Dabei werden zuerst die notwendigen theoretischen Grundlagen vorgestellt und anschließend wird die Methodik bei der Visualisierung von Daten eingesetzt. Die Persistente Homologie ist eines der Standardwerkzeuge in der TDA. Sie findet ihre Anwendung beispielsweise in den Bereichen Formerkennung und -beschreibung. Der Mapper als zweites wichtiges Konzept der TDA wandelt umfangreiche, h{\"o}herdimensionale Datens{\"a}tze in Simplizialkomplexe um und kann dadurch geometrische und topologische Eigenschaften der Daten bestimmen. Des Weiteren ist die Mapper-Methode ein brauchbares Werkzeug zur Visualisierungen von mehrdimensionalen Daten, woran statistische Verfahren scheitern.}, language = {de} } @misc{OPUS4-41639, title = {Dicion{\´a}rio de l{\´i}ngua geral amaz{\^o}nica}, editor = {Muller, Jean-Claude and Dietrich, Wolf and Monserrat, Ruth and Barros, C{\^a}ndida and Arenz, Karl-Heinz and Prudente, Gabriel}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, organization = {Museu Paraense Emilio Goeldi}, isbn = {978-85-61377-99-1}, doi = {10.25932/publishup-41639}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-416390}, pages = {384}, year = {2019}, abstract = {Permettez {\`a} l'inventeur du manuscrit dont vous avez l'{\´e}dition diplomatique sous les yeux d'exposer en exergue les principales {\´e}tapes qui ont conduit en 2012 {\`a} la d{\´e}termination de la langue et {\`a} l'identification de l'auteur. {\´E}tant inscrit {\`a} la conf{\´e}rence de linguistique missionnaire {\`a} l'universit{\´e} de Br{\`e}me en mars 2012 et conscient que maintes biblioth{\`e}ques et archives renferment des tr{\´e}sors non identifi{\´e}s ou mal catalogu{\´e}s, je suivis le conseil d'un coll{\`e}gue de la biblioth{\`e}que de l'universit{\´e} de Tr{\`e}ves, Hans-Ulrich Seiffert, d'inspecter le manuscrit 1136 / 2048 4° de la biblioth{\`e}que municipale de Tr{\`e}ves. Cette biblioth{\`e}que est riche de plus de 2.500 manuscrits et incunables provenant pour la plupart des saisies r{\´e}volutionnaires fran{\c{c}}aises dans les biblioth{\`e}ques des ci-devant couvents tr{\´e}virois. Parmi ces tr{\´e}sors un manuscrit portugais des missions qui {\´e}tait rentr{\´e} dans les fonds de la biblioth{\`e}que de Tr{\`e}ves d{\`e}s 1799 et avait {\´e}t{\´e} expos{\´e} en 1991 dans le cadre d'une {\´e}vocation des activit{\´e}s missionnaires globales des J{\´e}suites. Michael Embach, alors directeur de la biblioth{\`e}que du s{\´e}minaire {\´e}piscopal de Tr{\`e}ves, l'avait bri{\`e}vement d{\´e}crit dans une notice qui pr{\´e}tendait qu'il {\´e}tait r{\´e}dig{\´e} en espagnol et en portugais et avait peut-{\^e}tre {\´e}t{\´e} compos{\´e} par un auteur « Meirin » dans le cadre de ses pr{\´e}parations pour partir dans les missions… Dans ma copie du catalogue de 1991 se trouve inscrit « la langue reste {\`a} d{\´e}terminer ». J'allais r{\´e}soudre le myst{\`e}re en cette m{\´e}morable journ{\´e}e du jeudi 23 f{\´e}vrier 2012 quand je me r{\´e}solus {\`a} l'autopsier dans la salle d{\´e}sormais historique de la Biblioth{\`e}que municipale de Tr{\`e}ves, dirig{\´e}e depuis peu par le coll{\`e}gue Embach. Il parut {\`a} l'{\´e}vidence que le manuscrit ne contenait aucun mot d'espagnol mais que dans la premi{\`e}re partie, les entr{\´e}es en portugais, strictement num{\´e}rot{\´e}es et arrang{\´e}es dans l'ordre alphab{\´e}tique, {\´e}taient suivies par leurs {\´e}quivalences dans une langue inconnue qui, cependant, avait pour un linguiste une forte odeur de l'Am{\´e}rique amazonienne. La partie post{\´e}rieure du manuscrit pr{\´e}sentait l'arrangement inverse. Les entr{\´e}es dans la langue inconnue {\´e}taient suivies de leurs {\´e}quivalences portugaises. Ce n'est que plus tard que nous avons compris le myst{\´e}rieux ordre des lemmata dans cette partie, bas{\´e}e qu'elle est sur la rime finale des mots. Deux facteurs ont grandement facilit{\´e} l'identification de la langue inconnue : 1. la permission du directeur Embach de pouvoir prendre des photos de travail de tous les folios du manuscrit et 2. l'entr{\´e}e dans le premier catalogue de la Biblioth{\`e}que de Tr{\`e}ves de 1802 : "Codex maxime memorabiblis est, cum nondum grammatica praeter Lusitani Anchieta nota sit, et nullum vocabularium huius linguae existet. Sine dubio scriptum est a quodam Missionario Jesuita". Rentrant de Tr{\`e}ves chez moi, je fis une br{\`e}ve halte dans mon bureau d'alors pour consulter Internet. L'entr{\´e}e "Anchieta" dans l'encyclop{\´e}die {\´e}lectronique Wikipedia m'informait que ce j{\´e}suite portugais avait compos{\´e} une grammaire du Vieux Tupi, publi{\´e}e en 1595. Sous le vocable "Old Tupi" ensuite, j'appris que l'auto-d{\´e}signation pour cette langue est {\~n}eengat{\´u} (la bonne langue, le parler correct). De l{\`a} {\`a} retrouver au folio 25 de mes photos la traduction du portugais linguagem par nhe{\´e}nga ne prit que quelques minutes. D{\`e}s ce premier soir donc, le myst{\`e}re de la langue inconnue {\´e}tait r{\´e}solu! Un projet de recherche international, voire transcontinental allait se mettre peu {\`a} peu en place apr{\`e}s. {\`A} la conf{\´e}rence de Br{\`e}me, d{\´e}but mars 2012, je fis la connaissance du linguiste et romaniste, le professeur Wolf Dietrich de l'universit{\´e} de M{\"u}nster en Westphalie, un des meilleurs connaisseurs des parlers amazoniens. Il rentrait avec une copie de mes photos de travail et confirma bient{\^o}t l'importance du manuscrit de Tr{\`e}ves pour la connaissance de la Lingua Geral, le parler qui s'{\´e}tait d{\´e}velopp{\´e} {\`a} partir du Vieux Tupi moribond. Je communiquai {\´e}galement ma d{\´e}couverte au fr{\`e}re Karl-Heinz Arenz de la congr{\´e}gation des p{\`e}res de Steyl, originaire de l'Eifel allemande et enseignant d'histoire aux universit{\´e}s br{\´e}siliennes de Bel{\´e}m et de Santar{\´e}m dans l'{\´E}tat du Par{\´a}. Arenz est l'auteur d'une {\´e}tude sur le j{\´e}suite luxembourgeois Jean-Philippe Bettendorf, actif au Maranh{\~a}o dans la seconde moiti{\´e} du XVIIe si{\`e}cle. Nous avions collabor{\´e} en 2007 {\`a} une exposition didactique consacr{\´e}e {\`a} ce personnage. Arenz ne tarda pas {\`a} passer l'information sur le manuscrit de Tr{\`e}ves aux deux linguistes br{\´e}siliennes C{\^a}ndida Barros et Ruth Monserrat, qui {\`a} leur tour pr{\´e}sentaient un projet de recherche qui fut accept{\´e} par les autorit{\´e}s br{\´e}siliennes. Les reals de ce subside furent bien investis en effet : l'{\´e}tudiant doctoral Gabriel Prudente r{\´e}alisa une transcription int{\´e}grale du manuscrit de Tr{\`e}ves qui fit appara{\^i}tre des couches dialectales et sociolectales dans le texte, et m{\^e}me quelques mots allemands. La biblioth{\`e}que municipale de Tr{\`e}ves, quant {\`a} elle, contribua « en nature » les images digitales qui sont consultables sur les pages de gauche de cette {\´e}dition {\´e}lectronique. D{\´e}but avril 2014, nous f{\^i}mes tous connaissance personnellement dans le cadre d'un colloque {\`a} l'universit{\´e} de Bel{\´e}m o{\`u} fut d{\´e}cid{\´e}e la pr{\´e}sente {\´e}dition digitale et o{\`u} furent prononc{\´e}es la plupart des contributions scientifiques que vous pouvez lire en guise d'introduction. Restait {\`a} percer l'{\´e}nigme du v{\´e}ritable auteur du manuscrit. C{\^a}ndida Barros avait assez t{\^o}t propos{\´e} les noms de trois J{\´e}suites allemands, actifs dans les ann{\´e}es 1750 dans la r{\´e}gion du fleuve Xingu et chass{\´e}s par les mesures anti-j{\´e}suites du pouvoir portugais en 1756. L'{\´e}tude pal{\´e}ographique des Quattuor vota des trois candidats, aux archives centrales des J{\´e}suites {\`a} Rome, me permit d{\´e}but septembre 2015 d'{\´e}liminer les p{\`e}res Eckart et Kaulen et de ne retenir que Antonius Meisterburg, originaire de Bernkastel sur la Moselle, comme le scribe du manuscrit de Tr{\`e}ves. Qu'il me soit permis d'exprimer ma GRATITUDE {\`a} toutes celles et {\`a} tous ceux qui ont contribu{\´e} {\`a} cette belle aventure de d{\´e}couverte intellectuelle et scientifique et {\`a} rendre au Br{\´e}sil une petite pierre de son histoire.}, language = {pt} } @phdthesis{SchulteOsseili2019, author = {Schulte-Osseili, Christine}, title = {Vom Monomer zum Glykopolymer}, doi = {10.25932/publishup-43216}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-432169}, school = {Universit{\"a}t Potsdam}, pages = {xiii, 149}, year = {2019}, abstract = {Glykopolymere sind synthetische und nat{\"u}rlich vorkommende Polymere, die eine Glykaneinheit in der Seitenkette des Polymers tragen. Glykane sind durch die Glykan-Protein-Wechselwirkung verantwortlich f{\"u}r viele biologische Prozesse. Die Beteiligung der Glykanen in diesen biologischen Prozessen erm{\"o}glicht das Imitieren und Analysieren der Wechselwirkungen durch geeignete Modellverbindungen, z.B. der Glykopolymere. Dieses System der Glykan-Protein-Wechselwirkung soll durch die Glykopolymere untersucht und studiert werden, um die spezifische und selektive Bindung der Proteine an die Glykopolymere nachzuweisen. Die Proteine, die in der Lage sind, Kohlenhydratstrukturen selektiv zu binden, werden Lektine genannt. In dieser Dissertationsarbeit wurden verschiedene Glykopolymere synthetisiert. Dabei sollte auf einen effizienten und kosteng{\"u}nstigen Syntheseweg geachtet werden. Verschiedene Glykopolymere wurden durch funktionalisierte Monomere mit verschiedenen Zuckern, wie z.B. Mannose, Laktose, Galaktose oder N-Acetyl-Glukosamin als funktionelle Gruppe, hergestellt. Aus diesen funktionalisierten Glykomonomeren wurden {\"u}ber ATRP und RAFT-Polymerisation Glykopolymere synthetisiert. Die erhaltenen Glykopolymere wurden in Diblockcopolymeren als hydrophiler Block angewendet und die Selbstassemblierung in w{\"a}ssriger L{\"o}sung untersucht. Die Polymere formten in w{\"a}ssriger L{\"o}sung Mizellen, bei denen der Zuckerblock an der Oberfl{\"a}che der Mizellen sitzt. Die Mizellen wurden mit einem hydrophoben Fluoreszenzfarbstoff beladen, wodurch die CMC der Mizellenbildung bestimmt werden konnte. Außerdem wurden die Glykopolymere als Oberfl{\"a}chenbeschichtung {\"u}ber „Grafting from" mit SI-ATRP oder {\"u}ber „Grafting to" auf verschiedene Oberfl{\"a}chen gebunden. Durch die glykopolymerbschichteten Oberfl{\"a}chen konnte die Glykan Protein Wechselwirkung {\"u}ber spektroskopische Messmethoden, wie SPR- und Mikroring Resonatoren untersucht werden. Hierbei wurde die spezifische und selektive Bindung der Lektine an die Glykopolymere nachgewiesen und die Bindungsst{\"a}rke untersucht. Die synthetisierten Glykopolymere k{\"o}nnten durch Austausch der Glykaneinheit f{\"u}r andere Lektine adressierbar werden und damit ein weites Feld an anderen Proteinen erschließen. Die biovertr{\"a}glichen Glykopolymere w{\"a}ren alternativen f{\"u}r den Einsatz in biologischen Prozessen als Transporter von Medikamenten oder Farbstoffe in den K{\"o}rper. Außerdem k{\"o}nnten die funktionalisierten Oberfl{\"a}chen in der Diagnostik zum Erkennen von Lektinen eingesetzt werden. Die Glykane, die keine selektive und spezifische Bindung zu Proteinen eingehen, k{\"o}nnten als antiadsorptive Oberfl{\"a}chenbeschichtung z.B. in der Zellbiologie eingesetzt werden.}, language = {de} } @phdthesis{Meessen2019, author = {Meeßen, Christian}, title = {The thermal and rheological state of the Northern Argentinian foreland basins}, doi = {10.25932/publishup-43994}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-439945}, school = {Universit{\"a}t Potsdam}, pages = {xviii, 151}, year = {2019}, abstract = {The foreland of the Andes in South America is characterised by distinct along strike changes in surface deformational styles. These styles are classified into two end-members, the thin-skinned and the thick-skinned style. The superficial expression of thin-skinned deformation is a succession of narrowly spaced hills and valleys, that form laterally continuous ranges on the foreland facing side of the orogen. Each of the hills is defined by a reverse fault that roots in a basal d{\´e}collement surface within the sedimentary cover, and acted as thrusting ramp to stack the sedimentary pile. Thick-skinned deformation is morphologically characterised by spatially disparate, basement-cored mountain ranges. These mountain ranges are uplifted along reactivated high-angle crustal-scale discontinuities, such as suture zones between different tectonic terranes. Amongst proposed causes for the observed variation are variations in the dip angle of the Nazca plate, variation in sediment thickness, lithospheric thickening, volcanism or compositional differences. The proposed mechanisms are predominantly based on geological observations or numerical thermomechanical modelling, but there has been no attempt to understand the mechanisms from a point of data-integrative 3D modelling. The aim of this dissertation is therefore to understand how lithospheric structure controls the deformational behaviour. The integration of independent data into a consistent model of the lithosphere allows to obtain additional evidence that helps to understand the causes for the different deformational styles. Northern Argentina encompasses the transition from the thin-skinned fold-and-thrust belt in Bolivia, to the thick-skinned Sierras Pampeanas province, which makes this area a well suited location for such a study. The general workflow followed in this study first involves data-constrained structural- and density-modelling in order to obtain a model of the study area. This model was then used to predict the steady-state thermal field, which was then used to assess the present-day rheological state in northern Argentina. The structural configuration of the lithosphere in northern Argentina was determined by means of data-integrative, 3D density modelling verified by Bouguer gravity. The model delineates the first-order density contrasts in the lithosphere in the uppermost 200 km, and discriminates bodies for the sediments, the crystalline crust, the lithospheric mantle and the subducting Nazca plate. To obtain the intra-crustal density structure, an automated inversion approach was developed and applied to a starting structural model that assumed a homogeneously dense crust. The resulting final structural model indicates that the crustal structure can be represented by an upper crust with a density of 2800 kg/m³, and a lower crust of 3100 kg/m³. The Transbrazilian Lineament, which separates the Pampia terrane from the R{\´i}o de la Plata craton, is expressed as a zone of low average crustal densities. In an excursion, we demonstrate in another study, that the gravity inversion method developed to obtain intra-crustal density structures, is also applicable to obtain density variations in the uppermost lithospheric mantle. Densities in such sub-crustal depths are difficult to constrain from seismic tomographic models due to smearing of crustal velocities. With the application to the uppermost lithospheric mantle in the north Atlantic, we demonstrate in Tan et al. (2018) that lateral density trends of at least 125\,km width are robustly recovered by the inversion method, thereby providing an important tool for the delineation of subcrustal density trends. Due to the genetic link between subduction, orogenesis and retroarc foreland basins the question rises whether the steady-state assumption is valid in such a dynamic setting. To answer this question, I analysed (i) the impact of subduction on the conductive thermal field of the overlying continental plate, (ii) the differences between the transient and steady-state thermal fields of a geodynamic coupled model. Both studies indicate that the assumption of a thermal steady-state is applicable in most parts of the study area. Within the orogenic wedge, where the assumption cannot be applied, I estimated the transient thermal field based on the results of the conducted analyses. Accordingly, the structural model that had been obtained in the first step, could be used to obtain a 3D conductive steady-state thermal field. The rheological assessment based on this thermal field indicates that the lithosphere of the thin-skinned Subandean ranges is characterised by a relatively strong crust and a weak mantle. Contrarily, the adjacent foreland basin consists of a fully coupled, very strong lithosphere. Thus, shortening in northern Argentina can only be accommodated within the weak lithosphere of the orogen and the Subandean ranges. The analysis suggests that the d{\´e}collements of the fold-and-thrust belt are the shallow continuation of shear zones that reside in the ductile sections of the orogenic crust. Furthermore, the localisation of the faults that provide strain transfer between the deeper ductile crust and the shallower d{\´e}collement is strongly influenced by crustal weak zones such as foliation. In contrast to the northern foreland, the lithosphere of the thick-skinned Sierras Pampeanas is fully coupled and characterised by a strong crust and mantle. The high overall strength prevents the generation of crustal-scale faults by tectonic stresses. Even inherited crustal-scale discontinuities, such as sutures, cannot sufficiently reduce the strength of the lithosphere in order to be reactivated. Therefore, magmatism that had been identified to be a precursor of basement uplift in the Sierras Pampeanas, is the key factor that leads to the broken foreland of this province. Due to thermal weakening, and potentially lubrication of the inherited discontinuities, the lithosphere is locally weakened such that tectonic stresses can uplift the basement blocks. This hypothesis explains both the spatially disparate character of the broken foreland, as well as the observed temporal delay between volcanism and basement block uplift. This dissertation provides for the first time a data-driven 3D model that is consistent with geophysical data and geological observations, and that is able to causally link the thermo-rheological structure of the lithosphere to the observed variation of surface deformation styles in the retroarc foreland of northern Argentina.}, language = {en} } @techreport{MuellerWrohlich2019, type = {Working Paper}, author = {M{\"u}ller, Kai-Uwe and Wrohlich, Katharina}, title = {Does subsidized care for toddlers increase maternal labor supply?}, series = {CEPA Discussion Papers}, journal = {CEPA Discussion Papers}, number = {9}, issn = {2628-653X}, doi = {10.25932/publishup-42772}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-427727}, pages = {50}, year = {2019}, abstract = {Expanding public or publicly subsidized childcare has been a top social policy priority in many industrialized countries. It is supposed to increase fertility, promote children's development and enhance mothers' labor market attachment. In this paper, we analyze the causal effect of one of the largest expansions of subsidized childcare for children up to three years among industrialized countries on the employment of mothers in Germany. Identification is based on spatial and temporal variation in the expansion of publicly subsidized childcare triggered by two comprehensive childcare policy reforms. The empirical analysis is based on the German Microcensus that is matched to county level data on childcare availability. Based on our preferred specification which includes time and county fixed effects we find that an increase in childcare slots by one percentage point increases mothers' labor market participation rate by 0.2 percentage points. The overall increase in employment is explained by the rise in part-time employment with relatively long hours (20-35 hours per week). We do not find a change in full-time employment or lower part-time employment that is causally related to the childcare expansion. The effect is almost entirely driven by mothers with medium-level qualifications. Mothers with low education levels do not profit from this reform calling for a stronger policy focus on particularly disadvantaged groups in coming years.}, language = {en} }