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Im beruflichen Lehramt bilden sowohl der Mangel an Studierenden als auch hohe Abbruchquoten bzw. die Abwanderung in Unternehmen eine permanente Herausforderung, der im Rahmen des Projekts „FACE – Berufliches Lehramt“ (gefördert im Kontext der 3. Phase der Qualitätsoffensive Lehrerbildung) mit unterschiedlichen Maßnahmen begegnet werden soll. Die Entwicklungs- und Unterstützungsmaßnahmen im gewerblich-technischen Lehramt am Standort Freiburg fokussieren insbesondere die Aspekte Kohärenz und Professionsorientierung – zukünftig forciert durch studentische Reflexionsprozesse. Diese werden durch die Entwicklung eines Pilotstudiengangs ergänzt, welcher eine 52-wöchige betriebliche Praxis auf Facharbeiterebene (Facharbeiterbrief) in das Studium integriert. Darüber hinaus finden Facetten von Heterogenität/Inklusion und Deutsch als Zweitsprache/Deutsch als Fremdsprache (DaZ/DaF) als Querschnittskompetenzen Eingang in das Studium. Die in allen Bereichen erworbenen Handlungskompetenzen werden in den Schulpraxisphasen erprobt und anschließend kritisch-konstruktiv in Reflexionsseminaren aufgearbeitet. Im folgenden Beitrag soll kurz auf die Entstehung des Pilotstudiengangs unter reflexiven Aspekten eingegangen werden.
Lehrkräfte aller Fächer benötigen informatische Kompetenzen, um der wachsenden Alltagsrelevanz von Informatik und aktuell gültigen Lehrplänen gerecht zu werden. Beispielsweise verweist in Sachsen der Lehrplan für das Fach Gemeinschaftskunde, Rechtserziehung und Wirtschaft am Gymnasium mit dem für die Jahrgangsstufe 11 vorgesehenem Thema „Digitalisierung und sozialer Wandel“ auf Künstliche Intelligenz (KI) und explizit auf die Bedeutung der informatischen Bildung. Um die nötigen informatischen Grundlagen zu vermitteln, wurde für Lehramtsstudierende des Faches Politik ein Workshop erarbeitet, der die Grundlagen der Funktionsweise von KI anhand von überwachtem maschinellen Lernen in neuronalen Netzen vermittelt. Inhalt des Workshops ist es, mit Bezug auf gesellschaftliche Implikationen wie Datenschutz bei Trainingsdaten und algorithmic bias einen informierten Diskurs zu politischen Themen zu ermöglichen. Ziele des Workshops für Lehramtsstudierende mit dem Fach Politik sind: (1) Aufbau informatischer Kompetenzen in Bezug zum Thema KI, (2) Stärkung der Diskussionsfähigkeiten der Studierenden durch passende informatische Kompetenzen und (3) Anregung der Studierenden zum Transfer auf passende Themenstellungen im Politikunterricht. Das Evaluationskonzept umfasst eine Pre-Post-Befragung zur Zuversicht zur Vermittlungskompetenz unter Bezug auf maschinelles Lernen in neuronalen Netzen im Unterricht, sowie die Analyse einer abschließenden Diskussion. Für die Pre-Post-Befragung konnte eine Steigerung der Zuversicht zur Vermittlungskompetenz beobachtet werden. Die Analyse der Diskussion zeigte das Bewusstsein der Alltagsrelevanz des Themas KI bei den Teilnehmenden, aber noch keine Anwendung der informatischen Inhalte des Workshops zur Stützung der Argumente in der Diskussion.
Enge Kooperationsformen basieren auf Vertrauen und dementsprechend wurde seine zentrale Rolle für die Funktionsfähigkeit von Netzwerken in den letzten Jahren auch zunehmend anerkannt. Diese Bedeutung von Vertrauen wird in grenzüberschreitenden Netzwerken noch potenziert, da neben den mangelnden formalen Sanktionsmöglichkeiten und der Ungleichzeitigkeit des Tauschs die Unsicherheiten resultierend aus der Berührung unterschiedlicher Wirtschafts-, Kultur und Rechtsräume zunehmen, während gleichzeitig die Funktionsfähigkeit verschiedener Institutionen zur Reduzierung dieser Unsicherheiten abnimmt. Trotz dieser anerkannten Rolle, die Vertrauen in grenzüberschreitenden Kooperationen spielt, wird dem Aufbau von Vertrauen in grenzüberschreitenden Netzwerken und den Möglichkeiten einer gezielten Vertrauensförderung in der Literatur bisher nur wenig Beachtung geschenkt. Um diese Fragen näher zu untersuchen, wurde eine empirische Studie zwischen den deutschen, polnischen und tschechischen Akteuren des von der Europäischen Union geförderten Projektes Enlarge-Net durchgeführt. Die Ergebnisse dieser Studie zeigen, dass gemeinsame Erfahrungen und wiederholte Interaktion, direkte Kommunikation, institutionellen Rahmenbedingungen, soziale, kulturelle und räumliche Distanzen zwischen den Akteuren und Dritten Parteien einen entscheidenden Einfluss auf den Vertrauensaufbau zwischen den Akteuren eines grenzüberschreitenden Netzwerkes haben. Um den Prozess des Vertrauensaufbaus zu fördern, sollte ein Vertrauensmanagement eingeführt werden, das unter anderem auf die Schaffung formaler und informeller Austauschplattformen abzielt, die Qualität der Kommunikation verbessert und Regeln der Kooperation institutionalisiert. Doch bleibt zu beachten, dass es sich bei dem Aufbau von Vertrauen um einen langsamen und sich sukzessive verstärkenden Prozess handelt, der extrem empfindlich gegenüber Störungen ist, die den gesamten Prozess mit einem Schlag zum Erliegen bringen können.
Inhalt: Theoretische Begründung einer Besteuerung von Alterseinkünften Kritische Überprüfung einiger Argumente Die Reformvorschläge und das Simulationsmodell Die Simulationsergebnisse Kritische Bewertung der Ergebnisse Mit einem Kommentar von Hans-Peter Weikard: Rentenbesteuerung und Korrespondenzprinzip: 1. Wie selbstverständlich ist das Korrespondenzprinzip? 2. Die zeitliche Dimension des Korrespondenzprinzips 3. Eine unzulässige Interpretation 4. Fazit
Aus Warschauer Perspektive
(2006)
Die alleinige Ursache von Stottern ist weiterhin nicht abschließend geklärt. Auf neurofunktioneller und -morphologischer Ebene zeigen stotternde Personen Abweichungen in den Arealen, welche nicht nur für die Initiierung von sprechmotorischen Programmen, sondern auch für die Produktion und Perzeption von musikalischen Rhythmen zuständig sind. Unterschiede zu flüssigsprechenden Personen treten jedoch nicht nur im verbalen, sondern auch im nonverbal sensomotorischen Bereich auf, was auf eine Störung domänenübergreifender auditiv-motorischer Koordinationsprozesse hindeutet. Ausgehend davon wurde in einigen Studien postuliert, dass dem Störungsbild Stottern ein domänenübergreifendes Rhythmusdefizit zugrunde liegt. Im Gegensatz zu anderen Störungsbildern, welche auch Probleme in rhythmischen Aufgaben aufweisen, gibt es bis dato jedoch keine Intervention, welche dieses Defizit angeht. Es soll untersucht werden, ob ein nonverbales rhythmisches Training bei stotternden Kindern im Alter von zehn bis zwölf Jahren eine Verbesserung der sensomotorischen Synchronisationsfähigkeiten zur Folge hat. Zudem soll erforscht werden, ob es Transfereffekte auf die Sprechmotorik und Sprechflüssigkeit gibt. Für die vorliegende einfach verblindete Pilotstudie sollen 20 Kinder rekrutiert werden. Zehn davon werden randomisiert der Experimentalgruppe zugewiesen, welche das rhythmische Spiel Rhythm Workers über drei Wochen daheim auf einem Tablet spielen sollen. Die Kontrollgruppe spielt ein nicht-rhythmisches Bubble-Shooter-Spiel namens Frozen Bubble. Diese Studie könnte somit den Weg ebnen für technologieunterstützte Rehabilitationsmaßnahmen, welche darauf abzielen die rhythmisch-motorischen Defizite bei Stottern zu lindern.
Interdisziplinäres Zentrum für Musterdynamik und Angewandte Fernerkundung Workshop vom 9. - 10. Februar 2006
The ten-years presidency of Alberto Fujimori in Peru is a classic example of the sort of hybrid democracy that emerged in various Latin American countries in the 1990s, combining a mixture of democratic and clearly non-democratic elements. Fujimori was one of the more autocratic Latin American leaders of the 1990s, he is being the only regime formally to break with pre-existing constitutional rules. Closely tied to the military and intelligence apparatus, his government involved a concentration of political power that reduced the scope and autonomy of other branches of the state. But, unlike previous Latin American military dictatorships, Fujimori’s government enjoyed a considerable popularity, born out of disaffection for representative institutions. The article argues, however, that these characteristics of apparent strength carried within them the seeds of their own destruction. Far from establishing lasting political stability, the regime was weakly based. Within six weeks of his inauguration for a third term in July 2000, Fujimori was obliged to announce his intention to withdraw from politics. Two months later, he was ousted altogether.
Antarctic glacier forfields are extreme environments and pioneer sites for ecological succession. The Antarctic continent shows microbial community development as a natural laboratory because of its special environment, geographic isolation and little anthropogenic influence. Increasing temperatures due to global warming lead to enhanced deglaciation processes in cold-affected habitats and new terrain is becoming exposed to soil formation and accessible for microbial colonisation. This study aims to understand the structure and development of glacier forefield bacterial communities, especially how soil parameters impact the microorganisms and how those are adapted to the extreme conditions of the habitat. To this effect, a combination of cultivation experiments, molecular, geophysical and geochemical analysis was applied to examine two glacier forfields of the Larsemann Hills, East Antarctica. Culture-independent molecular tools such as terminal restriction length polymorphism (T-RFLP), clone libraries and quantitative real-time PCR (qPCR) were used to determine bacterial diversity and distribution. Cultivation of yet unknown species was carried out to get insights in the physiology and adaptation of the microorganisms. Adaptation strategies of the microorganisms were studied by determining changes of the cell membrane phospholipid fatty acid (PLFA) inventory of an isolated bacterium in response to temperature and pH fluctuations and by measuring enzyme activity at low temperature in environmental soil samples. The two studied glacier forefields are extreme habitats characterised by low temperatures, low water availability and small oligotrophic nutrient pools and represent sites of different bacterial succession in relation to soil parameters. The investigated sites showed microbial succession at an early step of soil formation near the ice tongue in comparison to closely located but rather older and more developed soil from the forefield. At the early step the succession is influenced by a deglaciation-dependent areal shift of soil parameters followed by a variable and prevalently depth-related distribution of the soil parameters that is driven by the extreme Antarctic conditions. The dominant taxa in the glacier forefields are Actinobacteria, Acidobacteria, Proteobacteria, Bacteroidetes, Cyanobacteria and Chloroflexi. The connection of soil characteristics with bacterial community structure showed that soil parameter and soil formation along the glacier forefield influence the distribution of certain phyla. In the early step of succession the relative undifferentiated bacterial diversity reflects the undifferentiated soil development and has a high potential to shift according to past and present environmental conditions. With progressing development environmental constraints such as water or carbon limitation have a greater influence. Adapting the culturing conditions to the cold and oligotrophic environment, the number of culturable heterotrophic bacteria reached up to 108 colony forming units per gram soil and 148 isolates were obtained. Two new psychrotolerant bacteria, Herbaspirillum psychrotolerans PB1T and Chryseobacterium frigidisoli PB4T, were characterised in detail and described as novel species in the family of Oxalobacteraceae and Flavobacteriaceae, respectively. The isolates are able to grow at low temperatures tolerating temperature fluctuations and they are not specialised to a certain substrate, therefore they are well-adapted to the cold and oligotrophic environment. The adaptation strategies of the microorganisms were analysed in environmental samples and cultures focussing on extracellular enzyme activity at low temperature and PLFA analyses. Extracellular phosphatases (pH 11 and pH 6.5), β-glucosidase, invertase and urease activity were detected in the glacier forefield soils at low temperature (14°C) catalysing the conversion of various compounds providing necessary substrates and may further play a role in the soil formation and total carbon turnover of the habitat. The PLFA analysis of the newly isolated species C. frigidisoli showed that the cold-adapted strain develops different strategies to maintain the cell membrane function under changing environmental conditions by altering the PLFA inventory at different temperatures and pH values. A newly discovered fatty acid, which was not found in any other microorganism so far, significantly increased at decreasing temperature and low pH and thus plays an important role in the adaption of C. frigidisoli. This work gives insights into the diversity, distribution and adaptation mechanisms of microbial communities in oligotrophic cold-affected soils and shows that Antarctic glacier forefields are suitable model systems to study bacterial colonisation in connection to soil formation.
Basic psychological needs theory postulates that a social environment that satisfies individuals’ three basic psychological needs of autonomy, competence, and relatedness leads to optimal growth and well-being. On the other hand, the frustration of these needs is associated with ill-being and depressive symptoms foremost investigated in non-clinical samples; yet, there is a paucity of research on need frustration in clinical samples. Survey data were compared between adult individuals with major depressive disorder (MDD; n = 115; 48.69% female; 38.46 years, SD = 10.46) with those of a non-depressed comparison sample (n = 201; 53.23% female; 30.16 years, SD = 12.81). Need profiles were examined with a linear mixed model (LMM). Individuals with depression reported higher levels of frustration and lower levels of satisfaction in relation to the three basic psychological needs when compared to non-depressed adults. The difference between depressed and non-depressed groups was significantly larger for frustration than satisfaction regarding the needs for relatedness and competence. LMM correlation parameters confirmed the expected positive correlation between the three needs. This is the first study showing substantial differences in need-based experiences between depressed and non-depressed adults. The results confirm basic assumptions of the self-determination theory and have preliminary implications in tailoring therapy for depression.
Rezensiertes Werk: Basten, Ludger: Postmoderner Urbanismus : Gestaltung in der städtischen Peripherie / Ludger Basten. - Münster : LIT, 2005. - X, 363 S. : Ill. - ( Schriften des Arbeitskreises Stadtzukünfte der Deutschen Gesellschaft für Geographie ; 1) Zugl.: Bochum, Univ., Habil.-Schr., 2005 ISBN 3-8258-8902-5
Rezensiertes Werk: Grenzen weltweit : Zonen, Linien, Mauern im historischen Vergleich / Joachim Becker; Andrea Komlosy (Hrsg.). - Wien : Promedia-Verl. [u.a.], 2004. - 234 S. : graph. Darst., Kt. - (Historische Sozialkunde : Internationale Entwicklung ; 23 ; Journal für Entwicklungspolitik : Ergänzungsband ; 15) ISBN 3-85371-220-7
Im Rahmen dieser Studie soll ermittelt werden, welche Bedeutung sowohl quantitative, als auch qualitative Kriterien für die Beurteilung von Risiken in den Akteursgruppen Manager, Verwaltungsangehörige, Experten und Laien einnehmen. Bei der Beurteilung von Umweltrisiken spielen neben quantitativen Beurteilungskriterien (z.B. der Schadenswahrscheinlichkeit) auch qualitative Kriterien (z.B. die ausgelösten Emotionen) eine zentrale Rolle, wie insbesondere die Ergebnisse der psychometrischen Risikoforschung zeigen.
Der vorliegende Beitrag befasst sich mit der Konstruktion eines Lehr-/ Lernszenarios polyvalenter Grundlagenvorlesungen in naturwissenschaftlichen Fachwissenschaften. Das Szenario verbindet klassische Vorlesungen mit virtuellen Elementen wie Online-Kursen, Online-Foren und Audience-Response-Systemen sowie dem Arbeiten in Kleingruppen mit Ansätzen des problemorientierten Lernens. Ziel ist es das Grundlagenwissen der Studierenden anzupassen, das Arbeiten in Gruppen zu fördern und problemorientiertes Lernen zu erlernen.
Microswimmers, i.e. swimmers of micron size experiencing low Reynolds numbers, have received a great deal of attention in the last years, since many applications are envisioned in medicine and bioremediation. A promising field is the one of magnetic swimmers, since magnetism is biocom-patible and could be used to direct or actuate the swimmers. This thesis studies two examples of magnetic microswimmers from a physics point of view.
The first system to be studied are magnetic cells, which can be magnetic biohybrids (a swimming cell coupled with a magnetic synthetic component) or magnetotactic bacteria (naturally occurring bacteria that produce an intracellular chain of magnetic crystals). A magnetic cell can passively interact with external magnetic fields, which can be used for direction. The aim of the thesis is to understand how magnetic cells couple this magnetic interaction to their swimming strategies, mainly how they combine it with chemotaxis (the ability to sense external gradient of chemical species and to bias their walk on these gradients). In particular, one open question addresses the advantage given by these magnetic interactions for the magnetotactic bacteria in a natural environment, such as porous sediments. In the thesis, a modified Active Brownian Particle model is used to perform simulations and to reproduce experimental data for different systems such as bacteria swimming in the bulk, in a capillary or in confined geometries. I will show that magnetic fields speed up chemotaxis under special conditions, depending on parameters such as their swimming strategy (run-and-tumble or run-and-reverse), aerotactic strategy (axial or polar), and magnetic fields (intensities and orientations), but it can also hinder bacterial chemotaxis depending on the system.
The second example of magnetic microswimmer are rigid magnetic propellers such as helices or random-shaped propellers. These propellers are actuated and directed by an external rotating magnetic field. One open question is how shape and magnetic properties influence the propeller behavior; the goal of this research field is to design the best propeller for a given situation. The aim of the thesis is to propose a simulation method to reproduce the behavior of experimentally-realized propellers and to determine their magnetic properties. The hydrodynamic simulations are based on the use of the mobility matrix. As main result, I propose a method to match the experimental data, while showing that not only shape but also the magnetic properties influence the propellers swimming characteristics.
Der Berufsbildungsbericht (BMBF, 2022) verweist darauf, dass inzwischen eine Viertelmillion junger Menschen im spezifischen Ausbildungssegment „Übergangssektor“ münden. Dazu zählen berufsorientierende (Aus-)Bildungsangebote, die u. a. das Nachholen eines allgemeinbildenden Schulabschlusses ermöglichen, jedoch zu keinem anerkannten Ausbildungsabschluss führen. Hierbei handelt es sich längst nicht mehr um einen institutionell gesonderten Bereich der beruflichen Bildung, sondern i. d. R. um einen schulorganisatorisch eigenständigen Bereich. Es gehört somit zum beruflichen Alltag von Lehrkräften der Beruflichen Bildung, in unterschiedlichen (Aus-)Bildungsgängen zu unterrichten. Diese Zielgruppe wird jedoch in der Lehrer:innenbildung kaum berücksichtigt und somit haben auch die Studierenden diese kaum im Blick. Das wirft die Frage auf, wie angehende Lehrkräfte für die besondere Zielgruppe der benachteiligten Jugendlichen in der beruflichen Bildung und die damit verbundenen Anforderungen an eine adressatengerechte Didaktik sensibilisiert werden können ? Der Beitrag stellt sowohl den Aufbau des Seminarkonzepts sowie ausgewählte Ergebnisse der seminarbegleitenden Forschung vor.
Es gibt aus unserer Sicht eine Reihe von Gründen, sich in der gewerkschaftlichen Bildungsarbeit von der Dominanz des Lehrplans abzuwenden und sich an Stelle dessen dem Lernenden in einer Weise zuzuwenden, die seine Deutungen, seine Handlungsmotive und seine Lerninteressen in den Vordergrund stellt. Für den Bildungspraktiker ergeben sich Gründe vor allem aus der wiederholten Erfahrung von Diskrepanzen. Erstens die Diskrepanzen, die zwischen der Definition von Lehrzielen und ihrem Erreichen in der Erwachsenenbildung bestehen. Zweitens die Diskrepanzen, die zwischen dem tatsächlich erlernten Wissen und seiner Umsetzung und Anwendung in der Praxis sich auftun. (aus dem Inhalt)
Das Forschungsprojekt „Workflow-Management-Systeme für Open-Access-Hochschulverlage (OA-WFMS)” ist eine Kooperation zwischen der HTWK Leipzig und der Universität Potsdam. Ziel ist es, die Bedarfe von Universitäts- und Hochschulverlagen und Anforderungen an ein Workflow-Management-Systeme (WFMS) zu analysieren, um daraus ein generisches Lastenheft zu erstellen. Das WFMS soll den Publikationsprozess in OA-Verlagen erleichtern, beschleunigen sowie die Verbreitung von Open Access und das nachhaltige, digitale wissenschaftliche Publizieren fördern.
Das Projekt baut auf den Ergebnissen der Projekte „Open-Access-Hochschulverlag (OA-HVerlag)“ und „Open-Access-Strukturierte-Kommunikation (OA-STRUKTKOMM)“ auf. Der diesem Bericht zugrunde liegende Auftaktworkshop fand 2024 in Leipzig mit Vertreter:innen von zehn Institutionen statt. Der Workshop diente dazu, Herausforderungen und Anforderungen an ein WFMS zu ermitteln sowie bestehende Lösungsansätze und Tools zu diskutieren.
Im Workshop wurden folgende Fragen behandelt:
a. Wie kann die Organisation und Überwachung von Publikationsprozessen in wissenschaftlichen Verlagen durch ein WFMS effizient gestaltet werden?
b. Welche Anforderungen muss ein WFMS erfüllen, um Publikationsprozesse optimal zu unterstützen?
c. Welche Schnittstellen müssen berücksichtigt werden, um die Interoperabilität der Systeme zu garantieren?
d. Welche bestehenden Lösungsansätze und Tools sind bereits im Einsatz und welche Vor- und Nachteile haben diese?
Der Workshop gliederte sich in zwei Teile : Teil 1 behandelte Herausforderungen und Anforderungen (Fragen a. bis c.), Teil 2 bestehende Lösungen und Tools (Frage d.). Die Ergebnisse des Workshops fließen in die Bedarfsanalyse des Forschungsprojekts ein.
Die im Bericht dokumentierten Ergebnisse zeigen die Vielzahl der Herausforderungen der bestehenden Ansätze bezüglich des OA-Publikationsmanagements . Die Herausforderungen zeigen sich insbesondere bei der Systemheterogenität, den individuellen Anpassungsbedarfen und der Notwendigkeit der systematischen Dokumentation. Die eingesetzten Unterstützungssysteme und Tools wie Dateiablagen, Projektmanagement- und Kommunikationstools können insgesamt den Anforderungen nicht genügen, für Teillösungen sind sie jedoch nutzbar. Deshalb muss die Integration bestehender Systeme in ein zu entwickelndes OA-WFMS in Betracht gezogen und die Interoperabilität der miteinander interagierenden Systeme gewährleistet werden. Die Beteiligten des Workshops waren sich einig, dass das OA-WFMS flexibel und modular aufgebaut werden soll. Einer konsortialen Softwareentwicklung und einem gemeinsamen Betrieb im Verbund wurde der Vorrang gegeben.
Der Workshop lieferte wertvolle Einblicke in die Arbeit der Hochschulverlage und bildet somit eine solide Grundlage für die in Folge zu erarbeitende weitere Bedarfsanalyse und die Erstellung des generischen Lastenheftes.
Der Sachverständigenrat zur Begutachtung der Entwicklung im Gesundheitswesen forderte bereits 2007 eine verbesserte Zusammenarbeit der Gesundheitsberufe und beschreibt in seinem Gutachten „Kooperation und Verantwortung als Voraussetzung einer zielorientierten Gesundheitsversorgung“ (S. 25). Mit der vorgestellten Arbeit wird untersucht, welche Modelle der berufsübergreifenden Kooperation in der ambulanten sprachtherapeutischen Praxis Anwendung finden und wie diese Kooperationen von Sprachtherapeut*innen bewertet werden. Zu diesem Zweck wurde ein Online-Fragebogen konzipiert. Anschließend wurden die Antworten von insgesamt 30 teilnehmenden Sprachtherapeut*innen ausgewertet. Dabei wurde deutlich, dass die viel diskutierte und häufig geforderte interprofessionelle Zusammenarbeit in der Praxis nur selten zu finden ist. Vielmehr arbeiten die befragten Sprachtherapeut*innen nach multiprofessionellen Modellen. Es fehlen berufsübergreifende Besprechungen, und der fachliche Austausch ist noch viel zu oft dem Engagement einzelner Personen überlassen. Auch die Bewertung der Kooperationen zeigt Verbesserungspotenzial: Die Befragten bewerteten die Zusammenarbeit mit angrenzenden Berufsgruppen durchschnittlich als „befriedigend“.
Der vorliegende 3. Band der „Schriften zum deutschen und russischen Strafrecht“ enthält die Vorträge, die an dem „Internationalen rechtsvergleichenden Runden Tisch zu aktuellen Themen des deutschen und russischen Strafrechts“, der am 18. Dezember 2012 an der Juristischen Fakultät der Universität Potsdam stattgefunden hat, gehalten wurden. Die Beiträge der Wissenschaftler und Praktiker aus Russland und Deutschland decken ein breites Spektrum an Themen ab, die in beiden Ländern von Interesse sind. In den Band aufgenommen wurden zudem der Festvortrag von Prof. Dr. Rarog zum Tag der Juristischen Fakultät der Universität Potsdam am 20. Juni 2012, ein Beitrag von Prof. Dr. Matskevich sowie ein weiterer Aufsatz von Prof. Dr. Rarog und Dr. Nagaeva. Die Publikation der Beiträge in deutscher und russischer Sprache ermöglicht den Lesern in beiden Ländern die Lektüre in der jeweiligen Muttersprache.
Betrachtungen zur Rolle von Frequenzmodulationen in der sozialen Kommunikation bei Tier und Mensch
(1998)
Bewegunglesen.com
(2014)
bewegunglesen.com (mit Silber bei den Best of Swiss Web Awards 2013 ausgezeichnet) ist ein E-Learning-Tool und bietet für Sportunterrichtende und Studierende eine webbasierte, interaktive Übungsgelegenheit, die Bewegungsanalyse und das kriteriengeleitete Verbessern von Fertigkeiten zu erlernen. Bewegungsabläufe mit ihren Kernbewegungen werden praxisnah und schulstufengerecht vermittelt. Daneben können auch Unterrichtsvideos hochgeladen, geschnitten, durch Grafiken und Fakten angereichert und innerhalb der Community geteilt werden. Aus den Clips lassen sich Übungen und Prüfungen mit Beurteilungskriterien des Bewegungsablaufs zusammenstellen, welche automatisiert ausgewertet werden.
Quantitative geomorphic research depends on accurate topographic data often collected via remote sensing. Lidar, and photogrammetric methods like structure-from-motion, provide the highest quality data for generating digital elevation models (DEMs). Unfortunately, these data are restricted to relatively small areas, and may be expensive or time-consuming to collect. Global and near-global DEMs with 1 arcsec (∼30 m) ground sampling from spaceborne radar and optical sensors offer an alternative gridded, continuous surface at the cost of resolution and accuracy. Accuracy is typically defined with respect to external datasets, often, but not always, in the form of point or profile measurements from sources like differential Global Navigation Satellite System (GNSS), spaceborne lidar (e.g., ICESat), and other geodetic measurements. Vertical point or profile accuracy metrics can miss the pixel-to-pixel variability (sometimes called DEM noise) that is unrelated to true topographic signal, but rather sensor-, orbital-, and/or processing-related artifacts. This is most concerning in selecting a DEM for geomorphic analysis, as this variability can affect derivatives of elevation (e.g., slope and curvature) and impact flow routing. We use (near) global DEMs at 1 arcsec resolution (SRTM, ASTER, ALOS, TanDEM-X, and the recently released Copernicus) and develop new internal accuracy metrics to assess inter-pixel variability without reference data. Our study area is in the arid, steep Central Andes, and is nearly vegetation-free, creating ideal conditions for remote sensing of the bare-earth surface. We use a novel hillshade-filtering approach to detrend long-wavelength topographic signals and accentuate short-wavelength variability. Fourier transformations of the spatial signal to the frequency domain allows us to quantify: 1) artifacts in the un-projected 1 arcsec DEMs at wavelengths greater than the Nyquist (twice the nominal resolution, so > 2 arcsec); and 2) the relative variance of adjacent pixels in DEMs resampled to 30-m resolution (UTM projected). We translate results into their impact on hillslope and channel slope calculations, and we highlight the quality of the five DEMs. We find that the Copernicus DEM, which is based on a carefully edited commercial version of the TanDEM-X, provides the highest quality landscape representation, and should become the preferred DEM for topographic analysis in areas without sufficient coverage of higher-quality local DEMs.
In biological cells, the long-range intracellular traffic is powered by molecular motors which transport various cargos along microtubule filaments. The microtubules possess an intrinsic direction, having a 'plus' and a 'minus' end. Some molecular motors such as cytoplasmic dynein walk to the minus end, while others such as conventional kinesin walk to the plus end. Cells typically have an isopolar microtubule network. This is most pronounced in neuronal axons or fungal hyphae. In these long and thin tubular protrusions, the microtubules are arranged parallel to the tube axis with the minus ends pointing to the cell body and the plus ends pointing to the tip. In such a tubular compartment, transport by only one motor type leads to 'motor traffic jams'. Kinesin-driven cargos accumulate at the tip, while dynein-driven cargos accumulate near the cell body. We identify the relevant length scales and characterize the jamming behaviour in these tube geometries by using both Monte Carlo simulations and analytical calculations. A possible solution to this jamming problem is to transport cargos with a team of plus and a team of minus motors simultaneously, so that they can travel bidirectionally, as observed in cells. The presumably simplest mechanism for such bidirectional transport is provided by a 'tug-of-war' between the two motor teams which is governed by mechanical motor interactions only. We develop a stochastic tug-of-war model and study it with numerical and analytical calculations. We find a surprisingly complex cooperative motility behaviour. We compare our results to the available experimental data, which we reproduce qualitatively and quantitatively.
A numerical bifurcation analysis of the electrically driven plane sheet pinch is presented. The electrical conductivity varies across the sheet such as to allow instability of the quiescent basic state at some critical Hartmann number. The most unstable perturbation is the two-dimensional tearing mode. Restricting the whole problem to two spatial dimensions, this mode is followed up to a time-asymptotic steady state, which proves to be sensitive to three-dimensional perturbations even close to the point where the primary instability sets in. A comprehensive three-dimensional stability analysis of the two-dimensional steady tearing-mode state is performed by varying parameters of the sheet pinch. The instability with respect to three-dimensional perturbations is suppressed by a sufficiently strong magnetic field in the invariant direction of the equilibrium. For a special choice of the system parameters, the unstably perturbed state is followed up in its nonlinear evolution and is found to approach a three-dimensional steady state.
Rezensierte Werke: Stegmann, Bernd-Achim: Großstadt im Image : eine wahrnehmungsgeographische Studie zu raumbezogenen Images und zum Imagemarketing in Printmedien am Beispiel Kölns und seiner Stadtviertel / Bernd-Achim Stegmann. - 1. Aufl. - Köln : Geograph. Inst. der Univ., 1997. - XII, 219 S. : Ill., graph. Darst., Kt. - (Kölner geographische Arbeiten ; 68) Zugl.: Köln, Univ., Diss., 1995 Körner, Wilfried: Der Frankfurter Grüngürtel als sozialer Raum : Diskurse, Raumbilder und Netzwerke - das Beispiel Sossenheim / von Wilfried Körner. - Frankfurt a.M. : Inst. für Kulturgeographie, Stadt- und Regionalforschung der J.-W.-Goethe-Univ., 1998. - 152 S. : Ill., Ktn. - (Materialien / Institut für Kulturgeographie, Stadt- und Regionalforschung der J.W. Goethe-Universität Frankfurt am Main ; 23) Nebent.: Frankfurter Grüngürtel ISBN 3-923218-16-8 Schüttemeyer, Anke: Eigen- und Fremdimage der Stadt Bonn : eine empirische Untersuchung / Anke Schüttemeyer. Geographisches Institut, Rheinische Friedrich-Wilhelms-Universität Bonn. - Bonn : Geograph. Inst., Lehrstuhl Grotz, 1998. - 109 S. : graph. Darst., Kt. - (Bonner Beiträge zur Geographie ; H. 9) Ganser, Karl: Liebe auf den zweiten Blick : Internationale Bauausstellung Emscher Park / Karl Ganser. - Dortmund : Harenberg, 1999. - 223 S. : Ill.; Kt. ISBN 3-611-00824-9 Kunst setzt Zeichen : Landmarken-Kunst ; Ausstellung vom 1. Mai bis Oktober 1999 in der Ludwig Galerie Schloss Oberhausen / hrsg. von Peter Pachnicke und Bernhard Mensch. - Oberhausen : Ludwig Galerie Schloß Oberhausen, 1999. - 213 S. : zahlr. Ill. ISBN 3-932236-07-6 Ausstellung vom 14. April bis 1. August 1999 im Rheinischen Industriemuseum Oberhausen / Daniel Stemmrich, Uwe Sülflohn (Red.). - Heidelberg, 1999. - 202 S. - (Schriften des Rheinischen Industriemuseums ; Bd. 16)
This study examined the spoken narrative skills of a group of bilingual Mandarin–English speaking 3–6-year-olds (N = 25) in Australia, using a remote online story-retell task. Bilingual preschoolers are an understudied population, especially those who are speaking typologically distinct languages such as Mandarin and English which have fewer structural overlaps compared to language pairs that are typologically closer, reducing cross-linguistic positive transfer. We examined these preschoolers’ spoken narrative skills as measured by macrostructures (the global organization of a story) and microstructures (linguistic structures, e.g., total number of utterances, nouns, verbs, phrases, and modifiers) across and within each language, and how various factors such as age and language experiences contribute to individual variability. The results indicate that our bilingual preschoolers acquired spoken narrative skills similarly across their two languages, i.e., showing similar patterns of productivity for macrostructure and microstructure elements in both of their two languages. While chronological age was positively correlated with macrostructures in both languages (showing developmental effects), there were no significant correlations between measures of language experiences and the measures of spoken narrative skills (no effects for language input/output). The findings suggest that although these preschoolers acquire two typologically diverse languages in different learning environments, Mandarin at home with highly educated parents, and English at preschool, they displayed similar levels of oral narrative skills as far as these macro−/micro-structure measures are concerned. This study provides further evidence for the feasibility of remote online assessment of preschoolers’ narrative skills.
The haemolymph of the adult Colorado potato beetle, Lepinotarsa decemlineata Say, contains a high molecular weight (MW > 200,000) JH-III specific binding protein. The Kd value of the protein for racemic JH-III is 1.3 ± 0.2 × 10−7 M. It has a lower affinity for racemic JH-I and it does not bind JH-III-diol or JH-III-acid. The binding protein does discriminate between the enantiomers of synthetic, racemic JH-III as was determined by stereochemical anaysis of the bound and the free JH-III. Incubation of racemic JH-III with crude haemolymph results in preferential formation of (10S)-JH-III-acid, the unnatural configuration. The JH-esterase present in L. decemlineata haemolymph is not enantioselective. It is concluded that the most important function of the binding protein is that of a specific carrier, protecting the natural hormone against degradation by esterases. The carrier does not protect JH-I as efficiently as the lower homologue.
Cardiovascular diseases are the main cause of death worldwide, and their prevalence is expected to rise in the coming years. Polymer-based artificial replacements have been widely used for the treatment of cardiovascular diseases. Coagulation and thrombus formation on the interfaces between the materials and the human physiological environment are key issues leading to the failure of the medical device in clinical implantation. The surface properties of the materials have a strong influence on the protein adsorption and can direct the blood cell adhesion behavior on the interfaces. Furthermore, implant-associated infections will be induced by bacterial adhesion and subsequent biofilm formation at the implantation site. Thus, it is important to improve the hemocompatibility of an implant by altering the surface properties. One of the effective strategies is surface passivation to achieve protein/cell repelling ability to reduce the risk of thrombosis.
This thesis consists of synthesis, functionalization, sterilization, and biological evaluation of bulk poly(glycerol glycidyl ether) (polyGGE), which is a highly crosslinked polyether-based polymer synthesized by cationic ring-opening polymerization. PolyGGE is hypothesized to be able to resist plasma protein adsorption and bacterial adhesion due to analogous chemical structure as polyethylene glycol and hyperbranched polyglycerol. Hydroxyl end groups of polyGGE provide possibilities to be functionalized with sulfates to mimic the anti-thrombogenic function of the endothelial glycocalyx.
PolyGGE was synthesized by polymerization of the commercially available monomer glycerol glycidyl ether, which was characterized as a mixture of mono-, di- and tri-glycidyl ether. Cationic ring opening-polymerization of this monomer was carried out by ultraviolet (UV) initiation of the photo-initiator diphenyliodonium hexafluorophosphate. With the increased UV curing time, more epoxides in the side chains of the monomers participated in chemical crosslinking, resulting in an increase of Young’s modulus, while the value of elongation at break of polyGGE first increased due to the propagation of the polymer chains then decreased with the increase of crosslinking density. Eventually, the chain propagation can be effectively terminated by potassium hydroxide aqueous solution. PolyGGE exhibited different tensile properties in hydrated conditions at body temperature compared to the values in the dry state at room temperature. Both Young’s modulus and values of elongation at break were remarkably reduced when tested in water at 37 °C, which was above the glass transition temperature of polyGGE. At physiological conditions, entanglements of the ployGGE networks unfolded and the free volume of networks were replaced by water molecules as softener, which increased the mobility of the polymer chains, resulting in a lower Young’s modulus.
Protein adsorption analysis was performed on polyGGE films with 30 min UV curing using an enzyme-linked immunosorbent assay. PolyGGE could effectively prevent the adsorption of human plasma fibrinogen, albumin, and fibronectin at the interface of human plasma and polyGGE films. The protein resistance of polyGGE was comparable to the negative controls: the hemocompatible polydimethylsiloxane (PDMS), showing its potential as a coating material for cardiovascular implants. Moreover, antimicrobial tests of bacterial activity using isothermal microcalorimetry and the microscopic image of direct bacteria culturing demonstrated that polyGGE could directly interfere biofilm formation and growth of both Gram-negative and antibiotic-resistant Gram-positive bacteria, indicating the potential application of polyGGE for combating the risk of hospital-acquired infections and preventing drug-resistant superbug spreading.
To investigate its cell compatibility, polyGGE films were extracted by different solvents (ethanol, chloroform, acetone) and cell culture medium. Indirect cytotoxicity tests showed extracted polyGGE films still had toxic effects on L929 fibroblast cells. High-performance liquid chromatography/electrospray ionization mass spectrometry revealed the occurrence of organochlorine-containing compounds released during the polymer-cell culture medium interaction. A constant level of those organochlorine-containing compounds was confirmed from GGE monomer by a specific peak of C-Cl stretching in infrared spectra of GGE. This is assumed to be the main reason causing the increased cell membrane permeability and decreased metabolic activity, leading to cell death. Attempts as changing solvents were made to remove toxic substances, however, the release of these small molecules seems to be sluggish. The densely crosslinked polyGGE networks can possibly contribute to the trapping of organochlorine-containing compounds. These results provide valuable information for exploring the potentially toxic substances, leaching from polyGGE networks, and propose a feasible strategy for minimizing the cytotoxicity via reducing their crosslinking density.
Sulfamic acid/ N-Methyl-2-pyrrolidone (NMP) were selected as the reagents for the sulfation of polyGGE surfaces. Fourier transform attenuated total reflection infrared spectroscopy (ATR-FT-IR) was used to monitor the functionalization kinetics and the results confirmed the successful sulfate grafting on the surface of polyGGE with the covalent bond -C-O-S-. X-ray photoelectron spectroscopy was used to determine the element composition on the surface and the cross-section of the functionalized polyGGE and sulfation within 15 min guarantees the sulfation only takes place on the surface while not occurring in the bulk of the polymer. The concentration of grafted sulfates increased with the increasing reaction time. The hydrophilicity of the surface of polyGGE was highly increased due to the increase of negatively charged end groups. Three sterilization techniques including autoclaving, gamma irradiation, and ethylene oxide (EtO) sterilization were used for polyGGE sulfates. Results from ATR-FT-IR and Toluidine Blue O quantitative assay demonstrated the total loss of the sulfates after autoclave sterilization, which was also confirmed by the increased water contact angle. Little influence on the concentration of sulfates was found for gamma-irradiated and autoclaving sterilized polyGGE sulfates. To investigate the thermal influence on polyGGE sulfates, one strategy was to use poly(hydroxyethyl acrylate) sulfates (PHEAS) for modeling. The thermogravimetric analysis profile of PHEAS demonstrated that sulfates are not thermally stable independent of the substrate materials and decomposition of sulfates occurs at around 100 °C. Although gamma irradiation also showed little negative effect on the sulfate content, the color change in the polyGGE sulfates indicates chemical or physical change might occur in the polymer. EtO sterilization was validated as the most suitable sterilization technique to maintain the chemical structure of polyGGE sulfates.
In conclusion, the conducted work proved that bulk polyGGE can be used as an antifouling coating material and shows its antimicrobial potential. Sulfates functionalization can be effectively realized using sulfamic acid/NMP. EtO sterilization is the most suitable sterilization technique for grafted sulfates. Besides, this thesis also offers a good strategy for the analysis of toxic leachable substances using suitable physicochemical characterization techniques. Future work will focus on minimizing/eliminating the release of toxic substances via reducing the crosslinking density. Another interesting aspect is to study whether grafted sulfates can meet the need for anti-thrombogenicity.
Inhalt: Problemstellung: Über Zwänge und Gesinnungen Nachhaltigkeit als moralisches Interesse und altbekannte Idee Das Kultur- und Geschichtsverständnis im Naturschutz: Heimat schaffen in einer modernen Welt Der Gestaltungsbegriff des Heimatschutzes: mit neuen Mitteln das Alte veredeln Die Entwicklung des Umweltschutzes und des wissenschaftlichen Naturschutzes – oder: Auf welchen Wegen sich alter Wein in neuen Schläuchen durchsetzt Fazit: Gleich und Gleich gesellt sich gern
Achilles tendinopathy (AT) is a debilitating injury in athletes, especially for those engaged in repetitive stretch-shortening cycle activities. Clinical risk factors are numerous, but it has been suggested that altered biomechanics might be associated with AT. No systematic review has been conducted investigating these biomechanical alterations in specifically athletic populations. Therefore, the aim of this systematic review was to compare the lower-limb biomechanics of athletes with AT to athletically matched asymptomatic controls. Databases were searched for relevant studies investigating biomechanics during gait activities and other motor tasks such as hopping, isolated strength tasks, and reflex responses. Inclusion criteria for studies were an AT diagnosis in at least one group, cross-sectional or prospective data, at least one outcome comparing biomechanical data between an AT and healthy group, and athletic populations. Studies were excluded if patients had Achilles tendon rupture/surgery, participants reported injuries other than AT, and when only within-subject data was available.. Effect sizes (Cohen's d) with 95% confidence intervals were calculated for relevant outcomes. The initial search yielded 4,442 studies. After screening, twenty studies (775 total participants) were synthesised, reporting on a wide range of biomechanical outcomes. Females were under-represented and patients in the AT group were three years older on average. Biomechanical alterations were identified in some studies during running, hopping, jumping, strength tasks and reflex activity. Equally, several biomechanical variables studied were not associated with AT in included studies, indicating a conflicting picture. Kinematics in AT patients appeared to be altered in the lower limb, potentially indicating a pattern of “medial collapse”. Muscular activity of the calf and hips was different between groups, whereby AT patients exhibited greater calf electromyographic amplitudes despite lower plantar flexor strength. Overall, dynamic maximal strength of the plantar flexors, and isometric strength of the hips might be reduced in the AT group. This systematic review reports on several biomechanical alterations in athletes with AT. With further research, these factors could potentially form treatment targets for clinicians, although clinical approaches should take other contributing health factors into account. The studies included were of low quality, and currently no solid conclusions can be drawn.
Blattgold : Pole Position
(2008)
Observers of international politics have been conscious of the growing international involvement of non-central governments (NCGs), particularly in federal systems. These have been supplemented by the internationalisation of subnational actors in quasi-federal and even unitary states. One of the difficulties is that analysis has often been locked into the dominant paradigm debate in International Relations concerning who and who are not significant actors. Having briefly explored the nature of this changing environment, marked by a growing emphasis on access rather than control as a policy objective and the emergence of what is termed a 'catalytic diplomacy', the discussion focuses on the need for linkage between the levels of government in the pursuit of international as well as domestic policy goals. The nature of linkage mechanisms are discussed.
Brothers: A Tale of Two Sons
(2020)
A method is presented of acquiring the principles of three sorting algorithms through developing interactive applications in Excel.
Bundistinnen
(2009)
Pri ha-Pardes (Früchte des Obstgartens) ist eine Reihe der Vereinigung für Jüdische Studien e.V., welche in Verbindung mit dem Zentrum für Jüdische Studien der Universität Potsdam publiziert wird. Pri ha-Pardes möchte kleineren wissenschaftlichen Studien, Forschungen am Rande der großen Disziplinen und exzellenten Masterarbeiten eine Publikationsplattform bieten. Im fünften Band der Reihe Pri ha-Pardes skizziert Rebekka Denz die Geschichte von Frauen im Allgemeinen Jüdischen Arbeiterbund („Bund“) seit seiner Gründung 1897 bis zum Jahr 1939. Durch das Prisma der gewählten Hauptquelle ─ die Frauenbiographien der „Doires Bundistn“, einer jiddischsprachigen Biographiensammlung verfasst von Mitgliedern des „Bund“ ─ werden das Mitwirken und die Bedeutung von Frauen in dieser sozialistischen, jiddischistischen Bewegung Ost(mittel)europas dargestellt. Zudem wird ein erster Versuch unternommen, diesen Teil der bundischen Parteigeschichtsschreibung hinsichtlich ihrer (Re-) Konstruktionsprinzipien zu lesen. Die Arbeit gliedert sich dabei analog zum bundischen Selbstverständnis und der geographischen Verschiebung seines Hauptwirkungsfeldes in zwei Teile: Frauen im „Russischen Bund“ (1897-1917) und Frauen im „Polnischen Bund“ (1918-1939). Die Auswirkungen der unterschiedlichen historischen Kontexte auf lebensweltliche Aspekte, Tätigkeiten in Bewegung und Partei sowie Tendenzen der Lebensgestaltung der Bundistinnen werden anhand von drei Vergleichskapiteln aufgezeigt; weitere Einzelkapitel behandeln zeitspezifische Aspekte. Die Instabilität der Lebensverhältnisse für die Mitglieder im illegalen „Russischen Bund“ bzw. die größere Stabilität in der Zeit des „Bund“ in Polen als legale Partei bilden wichtige, bislang vernachlässigte Faktoren bei der Betrachtung der weiblichen Lebensmuster.
Business process management aims at capturing, understanding, and improving work in organizations. The central artifacts are process models, which serve different purposes. Detailed process models are used to analyze concrete working procedures, while high-level models show, for instance, handovers between departments. To provide different views on process models, business process model abstraction has emerged. While several approaches have been proposed, a number of abstraction use case that are both relevant for industry and scientifically challenging are yet to be addressed. In this paper we systematically develop, classify, and consolidate different use cases for business process model abstraction. The reported work is based on a study with BPM users in the health insurance sector and validated with a BPM consultancy company and a large BPM vendor. The identified fifteen abstraction use cases reflect the industry demand. The related work on business process model abstraction is evaluated against the use cases, which leads to a research agenda.
Are we witnessing a decline of war, the spread of violence or both? The growing number of wars and genocids conveys the impression of uncontrolled violence. Is there any possibility to overcome belligerent conflicts between states? Do imply social, technological, cultural or even anthropological changes moments which could shift the ground of state’s rivalry towards non-belligerent relationships? Peace trough interdependence and democracy seems possible. The priorities of modern states cannot be thought on the basis of attributes like sovereignty and territoriality. The peaceful 'bourgeois islands' not only bring about prosperity but increasing social exclusion as well. New phenomenon of ethnicism and religiosity often originate from, around and in their midst. Threats arising from terrorism and racial or religious riots are the consequences. There are two options, the author considers as possible: an "embourgeoisement" of the "barbarians" or a "barbarisation of the bourgeois". Or is there a new political form emerging?
Basaltic fissure eruptions, such as on Hawai'i or on Iceland, are thought to be driven by the lateral propagation of feeder dikes and graben subsidence. Associated solid earth processes, such as deformation and structural development, are well studied by means of geophysical and geodetic technologies. The eruptions themselves, lava fountaining and venting dynamics, in turn, have been much less investigated due to hazardous access, local dimension, fast processes, and resulting poor data availability.
This thesis provides a detailed quantitative understanding of the shape and dynamics of lava fountains and the morphological changes at their respective eruption sites. For this purpose, I apply image processing techniques, including drones and fixed installed cameras, to the sequence of frames of video records from two well-known fissure eruptions in Hawai'i and Iceland. This way I extract the dimensions of multiple lava fountains, visible in all frames. By putting these results together and considering the acquisition times of the frames I quantify the variations in height, width and eruption velocity of the lava fountains. Then I analyse these time-series in both time and frequency domains and investigate the similarities and correlations between adjacent lava fountains. Following this procedure, I am able to link the dynamics of the individual lava fountains to physical parameters of the magma transport in the feeder dyke of the fountains.
The first case study in this thesis focuses on the March 2011 Pu'u'O'o eruption, Hawai'i, where a continuous pulsating behaviour at all eight lava fountains has been observed. The lava fountains, even those from different parts of the fissure that are closely connected, show a similar frequency content and eruption behaviour. The regular pattern in the heights of lava fountain suggests a controlling process within the magma feeder system like a hydraulic connection in the underlying dyke, affecting or even controlling the pulsating behaviour.
The second case study addresses the 2014-2015 Holuhraun fissure eruption, Iceland. In this case, the feeder dyke is highlighted by the surface expressions of graben-like structures and fault systems. At the eruption site, the activity decreases from a continuous line of fire of ~60 vents to a limited number of lava fountains. This can be explained by preferred upwards magma movements through vertical structures of the pre-eruptive morphology. Seismic tremors during the eruption reveal vent opening at the surface and/or pressure changes in the feeder dyke. The evolving topography of the cinder cones during the eruption interacts with the lava fountain behaviour. Local variations in the lava fountain height and width are controlled by the conduit diameter, the depth of the lava pond and the shape of the crater. Modelling of the fountain heights shows that long-term eruption behaviour is controlled mainly by pressure changes in the feeder dyke.
This research consists of six chapters with four papers, including two first author and two co-author papers. It establishes a new method to analyse lava fountain dynamics by video monitoring. The comparison with the seismicity, geomorphologic and structural expressions of fissure eruptions shows a complex relationship between focussed flow through dykes, the morphology of the cinder cones, and the lava fountain dynamics at the vents of a fissure eruption.
Fast analysis of different species of molecules in soils is investigated by capillary electrophoresis (CE). Several CE techniques for the analysis of inorganic ions and carbohydrates have been tested. With regard to the intents of pedologists and the usually large number of soil analyses a bundle of CE systems is proposed, capable of effecting time-saving soil analyses. Adapted electrolyte systems recently published and new separation systems are described. Examples of the application of these methods to two different soil samples are presented.
Solar photocatalysis is the one of leading concepts of research in the current paradigm of sustainable chemical industry. For actual practical implementation of sunlight-driven catalytic processes in organic synthesis, a cheap, efficient, versatile and robust heterogeneous catalyst is necessary. Carbon nitrides are a class of organic semiconductors who are known to fulfill these requirements.
First, current state of solar photocatalysis in economy, industry and lab research is overviewed, outlining EU project funding, prospective synthetic and reforming bulk processes, small scale solar organic chemistry, and existing reactor designs and prototypes, concluding feasibility of the approach.
Then, the photocatalytic aerobic cleavage of oximes to corresponding aldehydes and ketones by anionic poly(heptazine imide) carbon nitride is discussed. The reaction provides a feasible method of deprotection and formation of carbonyl compounds from nitrosation products and serves as a convenient model to study chromoselectivity and photophysics of energy transfer in heterogeneous photocatalysis.
Afterwards, the ability of mesoporous graphitic carbon nitride to conduct proton-coupled electron transfer was utilized for the direct oxygenation of 1,3-oxazolidin-2-ones to corresponding 1,3-oxazlidine-2,4-diones. This reaction provides an easier access to a key scaffold of diverse types of drugs and agrochemicals.
Finally, a series of novel carbon nitrides based on poly(triazine imide) and poly(heptazine imide) structure was synthesized from cyanamide and potassium rhodizonate. These catalysts demonstrated a good performance in a set of photocatalytic benchmark reactions, including aerobic oxidation, dual nickel photoredox catalysis, hydrogen peroxide evolution and chromoselective transformation of organosulfur precursors.
Concluding, the scope of carbon nitride utilization for net-oxidative and net-neutral photocatalytic processes was expanded, and a new tunable platform for catalyst synthesis was discovered.
4-Phenylphenoxazinones were isolated after biomimetic oxidation, using diphenoloxidases of insect cuticle, mushroom tyrosinase, or after autoxidation of N-acetyldopamine (Image ) in the presence of β-alanine, β-alanine methyl ester or N-acetyl-L-lysine. They are formed presumably by addition of 2-aminoalkyl-5-alkylphenols to the o-quinone of biphenyltetrol which, in turn, arises from oxidative coupling of. The structures of present the first examples for the assembly of reasonably stable intermediates in the rather complex process of chemical modifications of aliphatic amino acid residues by o-quinones.
Causes for slow weathering and erosion in the steep, warm, monsoon-subjected Highlands of Sri Lanka
(2018)
In the Highlands of Sri Lanka, erosion and chemical weathering rates are among the lowest for global mountain denudation. In this tropical humid setting, highly weathered deep saprolite profiles have developed from high-grade metamorphic charnockite during spheroidal weathering of the bedrock. The spheroidal weathering produces rounded corestones and spalled rindlets at the rock-saprolite interface. I used detailed textural, mineralogical, chemical, and electron-microscopic (SEM, FIB, TEM) analyses to identify the factors limiting the rate of weathering front advance in the profile, the sequence of weathering reactions, and the underlying mechanisms. The first mineral attacked by weathering was found to be pyroxene initiated by in situ Fe oxidation, followed by in situ biotite oxidation. Bulk dissolution of the primary minerals is best described with a dissolution – re-precipitation process, as no chemical gradients towards the mineral surface and sharp structural boundaries are observed at the nm scale. Only the local oxidation in pyroxene and biotite is better described with an ion by ion process. The first secondary phases are oxides and amorphous precipitates from which secondary minerals (mainly smectite and kaolinite) form. Only for biotite direct solid state transformation to kaolinite is likely. The initial oxidation of pyroxene and biotite takes place in locally restricted areas and is relatively fast: log J = -11 molmin/(m2 s). However, calculated corestone-scale mineral oxidation rates are comparable to corestone-scale mineral dissolution rates: log R = -13 molpx/(m2 s) and log R = -15 molbt/(m2 s). The oxidation reaction results in a volume increase. Volumetric calculations suggest that this observed oxidation leads to the generation of porosity due to the formation of micro-fractures in the minerals and the bedrock allowing for fluid transport and subsequent dissolution of plagioclase. At the scale of the corestone, this fracture reaction is responsible for the larger fractures that lead to spheroidal weathering and to the formation of rindlets. Since these fractures have their origin from the initial oxidational induced volume increase, oxidation is the rate limiting parameter for weathering to take place. The ensuing plagioclase weathering leads to formation of high secondary porosity in the corestone over a distance of only a few cm and eventually to the final disaggregation of bedrock to saprolite. As oxidation is the first weathering reaction, the supply of O2 is a rate-limiting factor for chemical weathering. Hence, the supply of O2 and its consumption at depth connects processes at the weathering front with erosion at the surface in a feedback mechanism. The strength of the feedback depends on the relative weight of advective versus diffusive transport of O2 through the weathering profile. The feedback will be stronger with dominating diffusive transport. The low weathering rate ultimately depends on the transport of O2 through the whole regolith, and on lithological factors such as low bedrock porosity and the amount of Fe-bearing primary minerals. In this regard the low-porosity charnockite with its low content of Fe(II) bearing minerals impedes fast weathering reactions. Fresh weatherable surfaces are a pre-requisite for chemical weathering. However, in the case of the charnockite found in the Sri Lankan Highlands, the only process that generates these surfaces is the fracturing induced by oxidation. Tectonic quiescence in this region and low pre-anthropogenic erosion rate (attributed to a dense vegetation cover) minimize the rejuvenation of the thick and cohesive regolith column, and lowers weathering through the feedback with erosion.
Wie beständig ist der Mythos „Barack Obama“? Klar ist: Der neue Präsident tritt ein schweres Erbe an. Herausforderungen wie die Wirtschaftskrise, schwierige außen- und sicherheitspolitische Gegebenheiten und die Beziehungen zu Russland warten auf ihn. Der Autor, ein exzellenter Kenner der USA und ehemaliger Diplomat, beleuchtet die Situation der Vereinigten Staaten nach der Wahl.
Recent years witnessed a vast advent of stalagmites as palaeoclimate archives. The multitude of geochemical and physical proxies and a promise of a precise and accurate age model greatly appeal to palaeoclimatologists. Although substantial progress was made in speleothem-based palaeoclimate research and despite high-resolution records from low-latitudinal regions, proving that palaeo-environmental changes can be archived on sub-annual to millennial time scales our comprehension of climate dynamics is still fragmentary. This is in particular true for the summer monsoon system on the Indian subcontinent. The Indian summer monsoon (ISM) is an integral part of the intertropical convergence zone (ITCZ). As this rainfall belt migrates northward during boreal summer, it brings monsoonal rainfall. ISM strength depends however on a variety of factors, including snow cover in Central Asia and oceanic conditions in the Indic and Pacific. Presently, many of the factors influencing the ISM are known, though their exact forcing mechanism and mutual relations remain ambiguous. Attempts to make an accurate prediction of rainfall intensity and frequency and drought recurrence, which is extremely important for South Asian countries, resemble a puzzle game; all interaction need to fall into the right place to obtain a complete picture. My thesis aims to create a faithful picture of climate change in India, covering the last 11,000 ka. NE India represents a key region for the Bay of Bengal (BoB) branch of the ISM, as it is here where the monsoon splits into a northwestward and a northeastward directed arm. The Meghalaya Plateau is the first barrier for northward moving air masses and receives excessive summer rainfall, while the winter season is very dry. The proximity of Meghalaya to the Tibetan Plateau on the one hand and the BoB on the other hand make the study area a key location for investigating the interaction between different forcings that governs the ISM. A basis for the interpretation of palaeoclimate records, and a first important outcome of my thesis is a conceptual model which explains the observed pattern of seasonal changes in stable isotopes (d18O and d2H) in rainfall. I show that although in tropical and subtropical regions the amount effect is commonly called to explain strongly depleted isotope values during enhanced rainfall, alone it cannot account for observed rainwater isotope variability in Meghalaya. Monitoring of rainwater isotopes shows no expected negative correlation between precipitation amount and d18O of rainfall. In turn I find evidence that the runoff from high elevations carries an inherited isotopic signature into the BoB, where during the ISM season the freshwater builds a strongly depleted plume on top of the marine water. The vapor originating from this plume is likely to memorize' and transmit further very negative d18O values. The lack of data does not allow for quantication of this plume effect' on isotopes in rainfall over Meghalaya but I suggest that it varies on seasonal to millennial timescales, depending on the runoff amount and source characteristics. The focal point of my thesis is the extraction of climatic signals archived in stalagmites from NE India. High uranium concentration in the stalagmites ensured excellent age control required for successful high-resolution climate reconstructions. Stable isotope (d18O and d13C) and grey-scale data allow unprecedented insights into millennial to seasonal dynamics of the summer and winter monsoon in NE India. ISM strength (i. e. rainfall amount) is recorded in changes in d18Ostalagmites. The d13C signal, reflecting drip rate changes, renders a powerful proxy for dry season conditions, and shows similarities to temperature-related changes on the Tibetan Plateau. A sub-annual grey-scale profile supports a concept of lower drip rate and slower stalagmite growth during dry conditions. During the Holocene, ISM followed a millennial-scale decrease of insolation, with decadal to centennial failures resulting from atmospheric changes. The period of maximum rainfall and enhanced seasonality corresponds to the Holocene Thermal Optimum observed in Europe. After a phase of rather stable conditions, 4.5 kyr ago, the strengthening ENSO system dominated the ISM. Strong El Nino events weakened the ISM, especially when in concert with positive Indian Ocean dipole events. The strongest droughts of the last 11 kyr are recorded during the past 2 kyr. Using the advantage of a well-dated stalagmite record at hand I tested the application of laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) to detect sub-annual to sub-decadal changes in element concentrations in stalagmites. The development of a large ablation cell allows for ablating sample slabs of up to 22 cm total length. Each analyzed element is a potential proxy for different climatic parameters. Combining my previous results with the LAICP- MS-generated data shows that element concentration depends not only on rainfall amount and associated leaching from the soil. Additional factors, like biological activity and hydrogeochemical conditions in the soil and vadose zone can eventually affect the element content in drip water and in stalagmites. I present a theoretical conceptual model for my study site to explain how climatic signals can be transmitted and archived in stalagmite carbonate. Further, I establish a first 1500 year long element record, reconstructing rainfall variability. Additionally, I hypothesize that volcanic eruptions, producing large amounts of sulfuric acid, can influence soil acidity and hence element mobilization.
In this work, binding interactions between biomolecules were analyzed by a technique that is based on electrically controllable DNA nanolevers. The technique was applied to virus-receptor interactions for the first time. As receptors, primarily peptides on DNA nanostructures and antibodies were utilized. The DNA nanostructures were integrated into the measurement technique and enabled the presentation of the peptides in a controllable geometrical order. The number of peptides could be varied to be compatible to the binding sites of the viral surface proteins.
Influenza A virus served as a model system, on which the general measurability was demonstrated. Variations of the receptor peptide, the surface ligand density, the measurement temperature and the virus subtypes showed the sensitivity and applicability of the technology. Additionally, the immobilization of virus particles enabled the measurement of differences in oligovalent binding of DNA-peptide nanostructures to the viral proteins in their native environment.
When the coronavirus pandemic broke out in 2020, work on binding interactions of a peptide from the hACE2 receptor and the spike protein of the SARS-CoV-2 virus revealed that oligovalent binding can be quantified in the switchSENSE technology. It could also be shown that small changes in the amino acid sequence of the spike protein resulted in complete loss of binding. Interactions of the peptide and inactivated virus material as well as pseudo virus particles could be measured. Additionally, the switchSENSE technology was utilized to rank six antibodies for their binding affinity towards the nucleocapsid protein of SARS-CoV-2 for the development of a rapid antigen test device.
The technique was furthermore employed to show binding of a non-enveloped virus (adenovirus) and a virus-like particle (norovirus-like particle) to antibodies. Apart from binding interactions, the use of DNA origami levers with a length of around 50 nm enabled the switching of virus material. This proved that the technology is also able to size objects with a hydrodynamic diameter larger than 14 nm.
A theoretical work on diffusion and reaction-limited binding interactions revealed that the technique and the chosen parameters enable the determination of binding rate constants in the reaction-limited regime.
Overall, the applicability of the switchSENSE technique to virus-receptor binding interactions could be demonstrated on multiple examples. While there are challenges that remain, the setup enables the determination of affinities between viruses and receptors in their native environment. Especially the possibilities regarding the quantification of oligo- and multivalent binding interactions could be presented.
Das Borna Disease Virus (BDV, Bornavirus) besitzt ein einzelsträngiges RNA-Genom negativer Polarität und ist innerhalb der Ordnung Mononegavirales der Prototyp einer eigenen Virusfamilie, die der Bornaviridae. Eine außergewöhnliche Eigenschaft des Virus ist seine nukleäre Transkription und Replikation, eine weitere besteht in seiner Fähigkeit, als neurotropes Virus sowohl in vivo als auch in vitro persistente Infektionen zu etablieren. Die zugrunde liegenden Mechanismen sowohl der Replikation als auch der Persistenz sind derzeit noch unzureichend verstanden, auch deshalb, weil das Virus noch relativ „jung“ ist: Erste komplette Sequenzen des RNA-Genoms wurden 1994 publiziert und erst vor einigen Monaten gelang die Generierung rekombinanter Viren auf der Basis klonierter cDNA. Im Mittelpunkt dieser Arbeit standen das p10 Protein und das Phosphoprotein (P), die von der gemeinsamen Transkriptionseinheit II in überlappenden Leserahmen kodiert werden. Als im Kern der Wirtszelle replizierendes Virus ist das Bornavirus auf zelluläre Importmechanismen angewiesen, um den Kernimport aller an der Replikation beteiligten viralen Proteine zu gewährleisten. Das p10 Protein ist ein negativer Regulator der viralen RNA-abhängigen RNA-Polymerase (L). In vitro Importexperimente zeigten, dass p10 über den klassischen Importin alpha/beta abhängigen Kernimportweg in den Nukleus transportiert wird. Dies war unerwartet, da p10 kein vorhersagbares klassisches Kernlokalisierungssignal (NLS) besitzt und weist darauf hin, dass der zelluläre Importapparat offensichtlich flexibler ist als allgemein angenommen. Die ersten 20 N-terminalen AS vermitteln sowohl Kernimport als auch die Bindung an den Importrezeptor Importin alpha. Durch Di-Alanin-Austauschmutagenese wurden die für diesen Transportprozess essentiellen AS identifiziert und die Bedeutung hydrophober und polarer AS-Reste demonstriert. Die Fähigkeit des Bornavirus, persistente Infektionen zu etablieren, wirft die Frage auf, wie das Virus die zellulären antiviralen Abwehrmechanismen, insbesondere das Typ I Interferon (IFN)-System, unterwandert. Das virale P Protein wurde in dieser Arbeit als potenter Antagonist der IFN-Induktion charakterisiert. Es verhindert die Phosphorylierung des zentralen Transkriptionsfaktors IRF3 durch die zelluläre Kinase TBK1 und somit dessen Aktivierung. Der Befund, dass P mit TBK1 Komplexe bildet und zudem auch als Substrat für die zelluläre Kinase fungiert, erlaubt es, erstmalig einen Mechanismus zu postulieren, in dem ein virales Protein (BDV-P) als putatives TBK1-Pseudosubstrat die IRF3-Aktivierung kompetitiv hemmt.
Die Aufgaben dieser Arbeit liegen in der Ermittlung einer Lebensstiltypologie für Gesamtdeutschland, der Untersuchung des Zusammenhangs zwischen sozialstrukturellen Merkmalen und dem Lebensstil und der Ermittlung der Wertorientierung der eruierten Lebensstile an Hand der Semiometrie. Inhalt: 1. Einleitung 2. Lebensstile 3. Ermittlung einer Lebensstiltypologie 3.1 Operationalisierung des Lebensstilkonzepts 3.2 Stichprobe 3.3 Faktorenanalyse 3.3.1 Faktoren und Faktorladungen 3.4 Clusteranalyse 3.4.1 Ermittlung der optimalen Clusterzahl 3.5 Sechs Lebensstile 3.5.1 Lebensstil der Ausschließlich kulturell Interessierten 3.5.2 Lebensstil der Einfachen Unbeteiligten 3.5.3 Lebensstil der Universell Aktiven 3.5.4 Lebensstil der Geselligen Spannungsorientierten 3.5.5 Lebensstil der Agilen Informationshungrigen 3.5.6 Lebensstil der Elektronikgeneigten Actionsuchenden 3.5.7 Vergleich der eruierten Lebensstile 4. Lebensstil im Zusammenhang mit sozialstrukturellen Merkmalen 4.1 Diskriminanzanalytische Ergebnisse 4.2 Zusammenfassung 5. Die Wertorientierung der Lebensstile 5.1 Methodik der Semiometrie 5.2 Wertsystem der Ausschließlich kulturell Interessierten 5.3 Wertsystem der Einfachen Unbeteiligten 5.4 Wertsystem der Universell Aktiven 5.5 Wertsystem der Geselligen Spannungsorientierten 5.6 Wertsystem der Agilen Informationshungrigen 5.7 Wertsystem der Elektronikgeneigten Actionsuchenden 5.8 Überblickspositionierung der Lebensstile und sozialstruktureller Merkmale 5.9 Fazit 6. Resümee
Chemical fingerprints of hydrological compartments and flow paths at La Cuenca, western Amazonia
(1995)
A forested first-order catchment in western Amazonia was monitored for 2 years to determine the chemical fingerprints of precipitation, throughfall, overland flow, pipe flow, soil water, groundwater, and streamflow. We used five tracers (hydrogen, calcium, magnesium, potassium, and silica) to distinguish “fast” flow paths mainly influenced by the biological subsystem from “slow” flow paths in the geochemical subsystem. The former comprise throughfall, overland flow, and pipe flow and are characterized by a high potassium/silica ratio; the latter are represented by soil water and groundwater, which have a low potassium/silica ratio. Soil water and groundwater differ with respect to calcium and magnesium. The groundwater-controlled streamflow chemistry is strongly modified by contributions from fast flow paths during precipitation events. The high potassium/silica ratio of these flow paths suggests that the storm flow response at La Cuenca is dominated by event water.
The Milky Way is only one out of billions of galaxies in the universe. However, it is a special galaxy because it allows to explore the main mechanisms involved in its evolution and formation history by unpicking the system star-by-star. Especially, the chemical fingerprints of its stars provide clues and evidence of past events in the Galaxy’s lifetime. These information help not only to decipher the current structure and building blocks of the Milky Way, but to learn more about the general formation process of galaxies.
In the past decade a multitude of stellar spectroscopic Galactic surveys have scanned millions of stars far beyond the rim of the solar neighbourhood. The obtained spectroscopic information provide unprecedented insights to the chemo-dynamics of the Milky Way. In addition analytic models and numerical simulations of the Milky Way provide necessary descriptions and predictions suited for comparison with observations in order to decode the physical properties that underlie the complex system of the Galaxy.
In the thesis various approaches are taken to connect modern theoretical modelling of galaxy formation and evolution with observations from Galactic stellar surveys. With its focus on the chemo-kinematics of the Galactic disk this work aims to determine new observational constraints on the formation of the Milky Way providing also proper comparisons with two different models. These are the population synthesis model TRILEGAL based on analytical distribution functions, which aims to simulate the number and distribution of stars in the Milky Way and its different components, and a hybrid model (MCM) that combines an N-body simulation of a Milky Way like galaxy in the cosmological framework with a semi-analytic chemical evolution model for the Milky Way. The major observational data sets in use come from two surveys, namely the “Radial Velocity Experiment” (RAVE) and the “Sloan Extension for Galactic Understanding and Exploration” (SEGUE).
In the first approach the chemo-kinematic properties of the thin and thick disk of the Galaxy as traced by a selection of about 20000 SEGUE G-dwarf stars are directly compared to the predictions by the MCM model. As a necessary condition for this, SEGUE's selection function and its survey volume are evaluated in detail to correct the spectroscopic observations for their survey specific selection biases. Also, based on a Bayesian method spectro-photometric distances with uncertainties below 15% are computed for the selection of SEGUE G-dwarfs that are studied up to a distance of 3 kpc from the Sun.
For the second approach two synthetic versions of the SEGUE survey are generated based on the above models. The obtained synthetic stellar catalogues are then used to create mock samples best resembling the compiled sample of observed SEGUE G-dwarfs. Generally, mock samples are not only ideal to compare predictions from various models. They also allow validation of the models' quality and improvement as with this work could be especially achieved for TRILEGAL. While TRILEGAL reproduces the statistical properties of the thin and thick disk as seen in the observations, the MCM model has shown to be more suitable in reproducing many chemo-kinematic correlations as revealed by the SEGUE stars. However, evidence has been found that the MCM model may be missing a stellar component with the properties of the thick disk that the observations clearly show. While the SEGUE stars do indicate a thin-thick dichotomy of the stellar Galactic disk in agreement with other spectroscopic stellar studies, no sign for a distinct metal-poor disk is seen in the MCM model.
Usually stellar spectroscopic surveys are limited to a certain volume around the Sun covering different regions of the Galaxy’s disk. This often prevents to obtain a global view on the chemo-dynamics of the Galactic disk. Hence, a suitable combination of stellar samples from independent surveys is not only useful for the verification of results but it also helps to complete the picture of the Milky Way. Therefore, the thesis closes with a comparison of the SEGUE G-dwarfs and a sample of RAVE giants. The comparison reveals that the chemo-kinematic relations agree in disk regions where the samples of both surveys show a similar number of stars. For those parts of the survey volumes where one of the surveys lacks statistics they beautifully complement each other. This demonstrates that the comparison of theoretical models on the one side, and the combined observational data gathered by multiple surveys on the other side, are key ingredients to understand and disentangle the structure and formation history of the Milky Way.
In the living cell, the organization of the complex internal structure relies to a large extent on molecular motors. Molecular motors are proteins that are able to convert chemical energy from the hydrolysis of adenosine triphosphate (ATP) into mechanical work. Being about 10 to 100 nanometers in size, the molecules act on a length scale, for which thermal collisions have a considerable impact onto their motion. In this way, they constitute paradigmatic examples of thermodynamic machines out of equilibrium. This study develops a theoretical description for the energy conversion by the molecular motor myosin V, using many different aspects of theoretical physics. Myosin V has been studied extensively in both bulk and single molecule experiments. Its stepping velocity has been characterized as a function of external control parameters such as nucleotide concentration and applied forces. In addition, numerous kinetic rates involved in the enzymatic reaction of the molecule have been determined. For forces that exceed the stall force of the motor, myosin V exhibits a 'ratcheting' behaviour: For loads in the direction of forward stepping, the velocity depends on the concentration of ATP, while for backward loads there is no such influence. Based on the chemical states of the motor, we construct a general network theory that incorporates experimental observations about the stepping behaviour of myosin V. The motor's motion is captured through the network description supplemented by a Markov process to describe the motor dynamics. This approach has the advantage of directly addressing the chemical kinetics of the molecule, and treating the mechanical and chemical processes on equal grounds. We utilize constraints arising from nonequilibrium thermodynamics to determine motor parameters and demonstrate that the motor behaviour is governed by several chemomechanical motor cycles. In addition, we investigate the functional dependence of stepping rates on force by deducing the motor's response to external loads via an appropriate Fokker-Planck equation. For substall forces, the dominant pathway of the motor network is profoundly different from the one for superstall forces, which leads to a stepping behaviour that is in agreement with the experimental observations. The extension of our analysis to Markov processes with absorbing boundaries allows for the calculation of the motor's dwell time distributions. These reveal aspects of the coordination of the motor's heads and contain direct information about the backsteps of the motor. Our theory provides a unified description for the myosin V motor as studied in single motor experiments.
Numerical magnitude information is assumed to be spatially represented in the form of a mental number line defined with respect to a body-centred, egocentric frame of reference. In this context, spatial language skills such as mastery of verbal descriptions of spatial position (e.g., in front of, behind, to the right/left) have been proposed to be relevant for grasping spatial relations between numerical magnitudes on the mental number line. We examined 4- to 5-year-old’s spatial language skills in tasks that allow responses in egocentric and allocentric frames of reference, as well as their relative understanding of numerical magnitude (assessed by a number word comparison task). In addition, we evaluated influences of children’s absolute understanding of numerical magnitude assessed by their number word comprehension (montring different numbers using their fingers) and of their knowledge on numerical sequences (determining predecessors and successors as well as identifying missing dice patterns of a series). Results indicated that when considering responses that corresponded to the egocentric perspective, children’s spatial language was associated significantly with their relative numerical magnitude understanding, even after controlling for covariates, such as children’s SES, mental rotation skills, and also absolute magnitude understanding or knowledge on numerical sequences. This suggests that the use of egocentric reference frames in spatial language may facilitate spatial representation of numbers along a mental number line and thus seem important for preschoolers’ relative understanding of numerical magnitude.
Infants show impressive speech decoding abilities and detect acoustic regularities that highlight the syntactic relations of a language, often coded via non-adjacent dependencies (NADs, e.g., is singing). It has been claimed that infants learn NADs implicitly and associatively through passive listening and that there is a shift from effortless associative learning to a more controlled learning of NADs after the age of 2 years, potentially driven by the maturation of the prefrontal cortex. To investigate if older children are able to learn NADs, Lammertink et al. (2019) recently developed a word-monitoring serial reaction time (SRT) task and could show that 6–11-year-old children learned the NADs, as their reaction times (RTs) increased then they were presented with violated NADs. In the current study we adapted their experimental paradigm and tested NAD learning in a younger group of 52 children between the age of 4–8 years in a remote, web-based, game-like setting (whack-a-mole). Children were exposed to Italian phrases containing NADs and had to monitor the occurrence of a target syllable, which was the second element of the NAD. After exposure, children did a “Stem Completion” task in which they were presented with the first element of the NAD and had to choose the second element of the NAD to complete the stimuli. Our findings show that, despite large variability in the data, children aged 4–8 years are sensitive to NADs; they show the expected differences in r RTs in the SRT task and could transfer the NAD-rule in the Stem Completion task. We discuss these results with respect to the development of NAD dependency learning in childhood and the practical impact and limitations of collecting these data in a web-based setting.
Chinas Wandel und die Welt
(2006)
Wie stellt sich das Verhältnis zwischen China und der Welt im 21. Jahrhundert dar? Die Autorin, Politikwissenschaftlerin aus Peking, verweist auf die aktuelle Debatte in China, in der das Primat der Innenpolitik, regionaler Multilateralismus und harmonische Weltordnung intensiv diskutiert werden. China habe nicht vor, das internationale System herauszufordern oder zu zerstören. Vielmehr sei es um stärkere Einbindung bemüht.
Chloroplasts as bioreactors : high-yield production of active bacteriolytic protein antibiotics
(2008)
Plants, more precisely their chloroplasts with their bacterial-like expression machinery inherited from their cyanobacterial ancestors, can potentially offer a cheap expression system for proteinaceous pharmaceuticals. This system would be easily scalable and provides appropriate safety due to chloroplasts maternal inheritance. In this work, it was shown that three phage lytic enzymes (Pal, Cpl-1 and PlyGBS) could be successfully expressed at very high levels and with high stability in tobacco chloroplasts. PlyGBS expression reached an amount of foreign protein accumulation (> 70% TSP) that has never been obtained before. Although the high expression levels of PlyGBS caused a pale green phenotype with retarded growth, presumably due to exhaustion of plastid protein synthesis capacity, development and seed production were not impaired under greenhouse conditions. Since Pal and Cpl-1 showed toxic effects when expressed in E. coli, a special plastid transformation vector (pTox) was constructed to allow DNA amplification in bacteria. The construction of the pTox transformation vector allowing a recombinase-mediated deletion of an E. coli transcription block in the chloroplast, leading to an increase of foreign protein accumulation to up to 40% of TSP for Pal and 20% of TSP for Cpl-1. High dose-dependent bactericidal efficiency was shown for all three plant-derived lytic enzymes using their pathogenic target bacteria S. pyogenes and S. pneumoniae. Confirmation of specificity was obtained for the endotoxic proteins Pal and Cpl-1 by application to E. coli cultures. These results establish tobacco chloroplasts as a new cost-efficient and convenient production platform for phage lytic enzymes and address the greatest obstacle for clinical application. The present study is the first report of lysin production in a non-bacterial system. The properties of chloroplast-produced lysins described in this work, their stability, high accumulation rate and biological activity make them highly attractive candidates for future antibiotics.
Der internationale Standard CityGML ist zu einer zentralen Schnittstelle für die geometrische wie semantische Beschreibung von 3D-Stadtmodellen geworden. Das Institut für Geodäsie und Geoinformationstechnik (IGG) der Technischen Universität Berlin leistet mit ihren Entwicklung der 3D City Database und der Importer/Exporter Software einen entscheidenden Beitrag die Komplexität von CityGML-Daten in einer Geodatenbank intuitiv und effizient nutzen zu können. Die Software des IGG ist Open Source, unterstützte mit Oracle Spatial (ab Version 10g) aber bisher nur ein proprietäres Datenbank Management System (DBMS). Im Rahmen dieser Masterarbeit wurde eine Portierung auf die freie Datenbank-Software PostgreSQL/PostGIS vorgenommen und mit der Performanz der Oracle-Version verglichen. PostGIS gilt als eine der ausgereiftesten Geodatenbanken und wurde in diesem Jahr mit dem Release der Version 2.0 nochmals um zahlreiche Funktionen und Features (u.a. auch 3D-Unterstützung) erweitert. Die Ergebnisse des Vergleiches sowie die umfangreiche Gegenüberstellung aller verwendeten Konzepte (SQL, PL, Java) geben Aufschluss auf die Charakteristika beider räumlicher DBMS und ermöglichen einen Erkenntnisgewinn über die Projektgrenzen hinaus.
A key problem for models of dialogue is to explain the mechanisms involved in generating and responding to clarification requests. We report a 'Maze task' experiment that investigates the effect of 'spoof' clarification requests on the development of semantic co-ordination. The results provide evidence of both local and global semantic co-ordination phenomena that are not captured by existing dialogue co-ordination models.
Die Anpassung von Sektoren an veränderte klimatische Bedingungen erfordert ein Verständnis von regionalen Vulnerabilitäten. Vulnerabilität ist als Funktion von Sensitivität und Exposition, welche potentielle Auswirkungen des Klimawandels darstellen, und der Anpassungsfähigkeit von Systemen definiert. Vulnerabilitätsstudien, die diese Komponenten quantifizieren, sind zu einem wichtigen Werkzeug in der Klimawissenschaft geworden. Allerdings besteht von der wissenschaftlichen Perspektive aus gesehen Uneinigkeit darüber, wie diese Definition in Studien umgesetzt werden soll. Ausdiesem Konflikt ergeben sich viele Herausforderungen, vor allem bezüglich der Quantifizierung und Aggregierung der einzelnen Komponenten und deren angemessenen Komplexitätsniveaus. Die vorliegende Dissertation hat daher zum Ziel die Anwendbarkeit des Vulnerabilitätskonzepts voranzubringen, indem es in eine systematische Struktur übersetzt wird. Dies beinhaltet alle Komponenten und schlägt für jede Klimaauswirkung (z.B. Sturzfluten) eine Beschreibung des vulnerablen Systems vor (z.B. Siedlungen), welches direkt mit einer bestimmten Richtung eines relevanten klimatischen Stimulus in Verbindung gebracht wird (z.B. stärkere Auswirkungen bei Zunahme der Starkregentage). Bezüglich der herausfordernden Prozedur der Aggregierung werden zwei alternative Methoden, die einen sektorübergreifenden Überblick ermöglichen, vorgestellt und deren Vor- und Nachteile diskutiert. Anschließend wird die entwickelte Struktur einer Vulnerabilitätsstudie mittels eines indikatorbasierten und deduktiven Ansatzes beispielhaft für Gemeinden in Nordrhein-Westfalen in Deutschland angewandt. Eine Übertragbarkeit auf andere Regionen ist dennoch möglich. Die Quantifizierung für die Gemeinden stützt sich dabei auf Informationen aus der Literatur. Da für viele Sektoren keine geeigneten Indikatoren vorhanden waren, werden in dieser Arbeit neue Indikatoren entwickelt und angewandt, beispielsweise für den Forst- oder Gesundheitssektor. Allerdings stellen fehlende empirische Daten bezüglich relevanter Schwellenwerte eine Lücke dar, beispielsweise welche Stärke von Klimaänderungen eine signifikante Auswirkung hervorruft. Dies führt dazu, dass die Studie nur relative Aussagen zum Grad der Vulnerabilität jeder Gemeinde im Vergleich zum Rest des Bundeslandes machen kann. Um diese Lücke zu füllen, wird für den Forstsektor beispielhaft die heutige und zukünftige Sturmwurfgefahr von Wäldern berechnet. Zu diesem Zweck werden die Eigenschaften der Wälder mit empirischen Schadensdaten eines vergangenen Sturmereignisses in Verbindung gebracht. Der sich daraus ergebende Sensitivitätswert wird anschließend mit den Windverhältnissen verknüpft. Sektorübergreifende Vulnerabilitätsstudien erfordern beträchtliche Ressourcen, was oft deren Anwendbarkeit erschwert. In einem nächsten Schritt wird daher das Potential einer Vereinfachung der Komplexität anhand zweier sektoraler Beispiele untersucht. Um das Auftreten von Waldbränden vorherzusagen, stehen zahlreiche meteorologische Indices zur Verfügung, welche eine Spannbreite unterschiedlicher Komplexitäten aufweisen. Bezüglich der Anzahl monatlicher Waldbrände weist die relative Luftfeuchtigkeit für die meisten deutschen Bundesländer eine bessere Vorhersagekraft als komplexere Indices auf. Dies ist er Fall, obgleich sie selbst als Eingangsvariable für die komplexeren Indices verwendet wird. Mit Hilfe dieses einzelnen meteorologischen Faktors kann also die Waldbrandgefahr in deutschen Region ausreichend genau ausgedrückt werden, was die Ressourceneffizienz von Studien erhöht. Die Methodenkomplexität wird auf ähnliche Weise hinsichtlich der Anwendung des ökohydrologischen Modells SWIM für die Region Brandenburg untersucht. Die interannuellen Bodenwasserwerte, welche durch dieses Modell simuliert werden, können nur unzureichend durch ein einfacheres statistisches Modell, welches auf denselben Eingangsdaten aufbaut, abgebildet werden. Innerhalb eines Zeithorizonts von Jahrzehnten, kann der statistische Ansatz jedoch das Bodenwasser zufriedenstellend abbilden und zeigt eine Dominanz der Bodeneigenschaft Feldkapazität. Dies deutet darauf hin, dass die Komplexität im Hinblick auf die Anzahl der Eingangsvariablen für langfristige Berechnungen reduziert werden kann. Allerdings sind die Aussagen durch fehlende beobachtete Bodenwasserwerte zur Validierung beschränkt. Die vorliegenden Studien zur Vulnerabilität und ihren Komponenten haben gezeigt, dass eine Anwendung noch immer wissenschaftlich herausfordernd ist. Folgt man der hier verwendeten Vulnerabilitätsdefinition, treten zahlreiche Probleme bei der Implementierung in regionalen Studien auf. Mit dieser Dissertation wurden Fortschritte bezüglich der aufgezeigten Lücken bisheriger Studien erzielt, indem eine systematische Struktur für die Beschreibung und Aggregierung von Vulnerabilitätskomponenten erarbeitet wurde. Hierfür wurden mehrere Ansätze diskutiert, die jedoch Vor- und Nachteile besitzen. Diese sollten vor der Anwendung von zukünftigen Studien daher ebenfalls sorgfältig abgewogen werden. Darüber hinaus hat sich gezeigt, dass ein Potential besteht einige Ansätze zu vereinfachen, jedoch sind hierfür weitere Untersuchungen nötig. Insgesamt konnte die Dissertation die Anwendung von Vulnerabilitätsstudien als Werkzeug zur Unterstützung von Anpassungsmaßnahmen stärken.
Being living systems unable to adjust their location to changing environmental conditions, plants display homeostatic networks that have evolved to maintain transition metal levels in a very narrow concentration range in order to avoid either deficiency or toxicity. Hence, plants possess a broad repertoire of mechanisms for the cellular uptake, compartmentation and efflux, as well as for the chelation of transition metal ions. A small number of plants are hypertolerant to one or a few specific transition metals. Some metal tolerant plants are also able to hyperaccumulate metal ions. The Brassicaceae family member Arabidopis halleri ssp. halleri (L.) O´KANE and AL´SHEHBAZ is a hyperaccumulator of zinc (Zn), and it is closely related to the non-hypertolerant and non-hyperaccumulating model plant Arabidopsis thaliana (L.) HEYNHOLD. The close relationship renders A. halleri a promising emerging model plant for the comparative investigation of the molecular mechanisms behind hypertolerance and hyperaccumulation. Among several potential candidate genes that are probably involved in mediating the zinc-hypertolerant and zinc-hyperaccumulating trait is AhHMA3. The AhHMA3 gene is highly similar to AtHMA3 (AGI number: At4g30120) in A. thaliana, and its encoded protein belongs to the P-type IB ATPase family of integral membrane transporter proteins that transport transition metals. In contrast to the low AtHMA3 transcript levels in A. thaliana, the gene was found to be constitutively highly expressed across different Zn treatments in A. halleri, especially in shoots. In this study, the cloning and characterisation of the HMA3 gene and its promoter from Arabidopsis halleri (L.) O´KANE and AL´SHEHBAZ and Arabidopsis thaliana (L.) HEYNHOLD is described. Heterologously expressed AhHMA3 mediated enhanced tolerance to Zn and to a much lesser degree to cadmium (Cd) but not to cobalt (Co) in metal-sensitive mutant strains of budding yeast. It is demonstrated that the genome of A. halleri contains at least four copies of AhHMA3, AhHMA3-1 to AhHMA3-4. A copy-specific real-time RT-PCR indicated that an AhHMA3-1 related gene copy is the source of the constitutively high transcript level in A. halleri and not a gene copy similar to AhHMA3-2 or AhHMA3-4. In accordance with the enhanced AtHMA3mRNA transcript level in A. thaliana roots, an AtHMA3 promoter-GUS gene construct mediated GUS activity predominantly in the vascular tissues of roots and not in shoots. However, the observed AhHMA3-1 and AhHMA3-2 promoter-mediated GUS activity in A. thaliana or A. halleri plants did not reflect the constitutively high expression of AhHMA3 in shoots of A. halleri. It is suggested that other factors e. g. characteristic sequence inserts within the first intron of AhHMA3-1 might enable a constitutively high expression. Moreover, the unknown promoter of the AhHMA3-3 gene copy could be the source of the constitutively high AhHMA3 transcript levels in A. halleri. In that case, the AhHMA3-3 sequence is predicted to be highly homologous to AhHMA3-1. The lack of solid localisation data for the AhHMA3 protein prevents a clear functional assignment. The provided data suggest several possible functions of the AhHMA3 protein: Like AtHMA2 and AtHMA4 it might be localised to the plasma membrane and could contribute to the efficient translocation of Zn from root to shoot and/or to the cell-to-cell distribution of Zn in the shoot. If localised to the vacuolar membrane, then a role in maintaining a low cytoplasmic zinc concentration by vacuolar zinc sequestration is possible. In addition, AhHMA3 might be involved in the delivery of zinc ions to trichomes and mesophyll leaf cells that are major zinc storage sites in A. halleri.
Observational evidence exists that winds of massive stars are clumped. Many massive star systems are known as non-thermal particle production sites, as indicated by their synchrotron emission in the radio band. As a consequence they are also considered as candidate sites for non-thermal high-energy photon production up to gamma-ray energies. The present work considers the effects of wind clumpiness expected on the emitting relativistic particle spectrum in colliding wind systems, built up from the pool of thermal wind particles through diffusive particle acceleration, and taking into account inverse Compton and synchrotron losses. In comparison to a homogeneous wind, a clumpy wind causes flux variations of the emitting particle spectrum when the clump enters the wind collision region. It is found that the spectral features associated with this variability moves temporally from low to high energy bands with the time shift between any two spectral bands being dependent on clump size, filling factor, and the energy-dependence of particle energy gains and losses.
Clumping in Galactic WN stars : a comparison of mass loss rates from UV/optical & radio diagnostics
(2007)
The mass loss rates and other parameters for a large sample of Galactic WN stars have been revised by Hamann et al. (2006), using the most up-to date Potsdam Wolf-Rayet (PoWR) model atmospheres. For a sub-sample of these stars exist measurements of their radio free-free emission. After harmonizing the adopted distance and terminal wind velocities, we compare the mass loss rates obtained from the two diagnostics. The differences are discussed as a possible consequence of different clumping contrast in the line-forming and radio-emitting regions.
Stellar winds play an important role for the evolution of massive stars and their cosmic environment. Multiple lines of evidence, coming from spectroscopy, polarimetry, variability, stellar ejecta, and hydrodynamic modeling, suggest that stellar winds are non-stationary and inhomogeneous. This is referred to as 'wind clumping'. The urgent need to understand this phenomenon is boosted by its far-reaching implications. Most importantly, all techniques to derive empirical mass-loss rates are more or less corrupted by wind clumping. Consequently, mass-loss rates are extremely uncertain. Within their range of uncertainty, completely different scenarios for the evolution of massive stars are obtained. Settling these questions for Galactic OB, LBV and Wolf-Rayet stars is prerequisite to understanding stellar clusters and galaxies, or predicting the properties of first-generation stars. In order to develop a consistent picture and understanding of clumped stellar winds, an international workshop on 'Clumping in Hot Star Winds' was held in Potsdam, Germany, from 18. - 22. June 2007. About 60 participants, comprising almost all leading experts in the field, gathered for one week of extensive exchange and discussion. The Scientific Organizing Committee (SOC) included John Brown (Glasgow), Joseph Cassinelli (Madison), Paul Crowther (Sheffield), Alex Fullerton (Baltimore), Wolf-Rainer Hamann (Potsdam, chair), Anthony Moffat (Montreal), Stan Owocki (Newark), and Joachim Puls (Munich). These proceedings contain the invited and contributed talks presented at the workshop, and document the extensive discussions.
Clumping in O-star winds
(2007)
We have analyzed the spectra of seven Galactic O4 supergiants, with the NLTE wind code CMFGEN. For all stars, we have found that clumped wind models match well lines from different species spanning a wavelength range from FUV to optical, and remain consistent with Hα data. We have achieved an excellent match of the P V λλ1118, 1128 resonance doublet and N IV λ1718, as well as He II λ4686 suggesting that our physical description of clumping is adequate. We find very small volume filling factors and that clumping starts deep in the wind, near the sonic point. The most crucial consequence of our analysis is that the mass loss rates of O stars need to be revised downward significantly, by a factor of 3 and more compared to those obtained from smooth-wind models.
Recent studies of massive O-type stars present clear evidences of inhomogeneous and clumped winds. O-type (H-rich) central stars of planetary nebulae (CSPNs) are in some ways the low mass–low luminosity analogous of those massive stars. In this contribution, we present preliminary results of our on-going multi-wavelength (FUV, UV and optical) study of the winds of Galactic CSPNs. Particular emphasis will be given to the clumping factors derived by means of optical lines (Hα and Heii 4686) and “classic” FUV (and UV) lines.
Sich mit dem eigenen Denken und Handeln reflexiv auseinanderzusetzen ist ein zentrales Element im Selbstreifungsprozess von Lehrkräften im Studium, über die Ausbildung bis hin zur Lehrer:innentätigkeit im Alltag. Der Workshop ermöglichte Zugänge zur selbstreflexiven Auseinandersetzung mit den eigenen Handlungsmustern mithilfe vom Autor (weiter)entwickelter Coachingtools, die im Rahmen der seminaristischen Lehrer:innenbildung in der zweiten Phase konzipiert und erprobt wurden.
Background
Communicating a diagnosis is highly important, yet complex, especially in the context of cancer and mental disorders. The aim was to explore the communication style of an oncologist vs. psychotherapist in an online study.
Methods
Patients (N = 136: 65 cancer, 71 depression) were randomly assigned to watch a standardized video vignette with one of two communication styles (empathic vs. unempathic). Outcome measures of affectivity, information recall, communication skills, empathy and trust were applied.
Results
Regardless of diagnosis, empathic communication was associated with the perception of a significantly more empathic (p < 0.001, η2partial = 0.08) and trustworthy practitioner (p = 0.014, η2partial = 0.04) with better communication skills (p = 0.013, η2partial = 0.05). Cancer patients reported a larger decrease in positive affect (p < 0.001, η2partial = 0.15) and a larger increase in negative affect (p < 0.001, η2partial = 0.14) from pre- to post-video than depressive patients. Highly relevant information was recalled better in both groups (p < 0.001, d = 0.61–1.06).
Conclusions
The results highlight the importance of empathy while communicating both a diagnosis of cancer and a mental disorder. Further research should focus on the communication of a mental disorder in association with cancer.
The Arctic is a particularly sensitive area with respect to climate change due to the high surface albedo of snow and ice and the extreme radiative conditions. Clouds and aerosols as parts of the Arctic atmosphere play an important role in the radiation budget, which is, as yet, poorly quantified and understood. The LIDAR (Light Detection And Ranging) measurements presented in this PhD thesis contribute with continuous altitude resolved aerosol profiles to the understanding of occurrence and characteristics of aerosol layers above Ny-Ålesund, Spitsbergen. The attention was turned to the analysis of periods with high aerosol load. As the Arctic spring troposphere exhibits maximum aerosol optical depths (AODs) each year, March and April of both the years 2007 and 2009 were analyzed. Furthermore, stratospheric aerosol layers of volcanic origin were analyzed for several months, subsequently to the eruptions of the Kasatochi and Sarychev volcanoes in summer 2008 and 2009, respectively. The Koldewey Aerosol Raman LIDAR (KARL) is an instrument for the active remote sensing of atmospheric parameters using pulsed laser radiation. It is operated at the AWIPEV research base and was fundamentally upgraded within the framework of this PhD project. It is now equipped with a new telescope mirror and new detection optics, which facilitate atmospheric profiling from 450m above sea level up to the mid-stratosphere. KARL provides highly resolved profiles of the scattering characteristics of aerosol and cloud particles (backscattering, extinction and depolarization) as well as water vapor profiles within the lower troposphere. Combination of KARL data with data from other instruments on site, namely radiosondes, sun photometer, Micro Pulse LIDAR, and tethersonde system, resulted in a comprehensive data set of scattering phenomena in the Arctic atmosphere. The two spring periods March and April 2007 and 2009 were at first analyzed based on meteorological parameters, like local temperature and relative humidity profiles as well as large scale pressure patterns and air mass origin regions. Here, it was not possible to find a clear correlation between enhanced AOD and air mass origin. However, in a comparison of two cloud free periods in March 2007 and April 2009, large AOD values in 2009 coincided with air mass transport through the central Arctic. This suggests the occurrence of aerosol transformation processes during the aerosol transport to Ny-Ålesund. Measurements on 4 April 2009 revealed maximum AOD values of up to 0.12 and aerosol size distributions changing with altitude. This and other performed case studies suggest the differentiation between three aerosol event types and their origin: Vertically limited aerosol layers in dry air, highly variable hygroscopic boundary layer aerosols and enhanced aerosol load across wide portions of the troposphere. For the spring period 2007, the available KARL data were statistically analyzed using a characterization scheme, which is based on optical characteristics of the scattering particles. The scheme was validated using several case studies. Volcanic eruptions in the northern hemisphere in August 2008 and June 2009 arose the opportunity to analyze volcanic aerosol layers within the stratosphere. The rate of stratospheric AOD change was similar within both years with maximum values above 0.1 about three to five weeks after the respective eruption. In both years, the stratospheric AOD persisted at higher rates than usual until the measurements were stopped in late September due to technical reasons. In 2008, up to three aerosol layers were detected, the layer structure in 2009 was characterized by up to six distinct and thin layers which smeared out to one broad layer after about two months. The lowermost aerosol layer was continuously detected at the tropopause altitude. Three case studies were performed, all revealed rather large indices of refraction of m = (1.53–1.55) - 0.02i, suggesting the presence of an absorbing carbonaceous component. The particle radius, derived with inversion calculations, was also similar in both years with values ranging from 0.16 to 0.19 μm. However, in 2009, a second mode in the size distribution was detected at about 0.5 μm. The long term measurements with the Koldewey Aerosol Raman LIDAR in Ny-Ålesund provide the opportunity to study Arctic aerosols in the troposphere and the stratosphere not only in case studies but on longer time scales. In this PhD thesis, both, tropospheric aerosols in the Arctic spring and stratospheric aerosols following volcanic eruptions have been described qualitatively and quantitatively. Case studies and comparative studies with data of other instruments on site allowed for the analysis of microphysical aerosol characteristics and their temporal evolution.
We formalize and analyze the notions of monotonicity and complete monotonicity for Markov Chains in continuous-time, taking values in a finite partially ordered set. Similarly to what happens in discrete-time, the two notions are not equivalent. However, we show that there are partially ordered sets for which monotonicity and complete monotonicity coincide in continuoustime but not in discrete-time.
Complex network theory provides an elegant and powerful framework to statistically investigate the topology of local and long range dynamical interrelationships, i.e., teleconnections, in the climate system. Employing a refined methodology relying on linear and nonlinear measures of time series analysis, the intricate correlation structure within a multivariate climatological data set is cast into network form. Within this graph theoretical framework, vertices are identified with grid points taken from the data set representing a region on the the Earth's surface, and edges correspond to strong statistical interrelationships between the dynamics on pairs of grid points. The resulting climate networks are neither perfectly regular nor completely random, but display the intriguing and nontrivial characteristics of complexity commonly found in real world networks such as the internet, citation and acquaintance networks, food webs and cortical networks in the mammalian brain. Among other interesting properties, climate networks exhibit the "small-world" effect and possess a broad degree distribution with dominating super-nodes as well as a pronounced community structure. We have performed an extensive and detailed graph theoretical analysis of climate networks on the global topological scale focussing on the flow and centrality measure betweenness which is locally defined at each vertex, but includes global topological information by relying on the distribution of shortest paths between all pairs of vertices in the network. The betweenness centrality field reveals a rich internal structure in complex climate networks constructed from reanalysis and atmosphere-ocean coupled general circulation model (AOGCM) surface air temperature data. Our novel approach uncovers an elaborately woven meta-network of highly localized channels of strong dynamical information flow, that we relate to global surface ocean currents and dub the backbone of the climate network in analogy to the homonymous data highways of the internet. This finding points to a major role of the oceanic surface circulation in coupling and stabilizing the global temperature field in the long term mean (140 years for the model run and 60 years for reanalysis data). Carefully comparing the backbone structures detected in climate networks constructed using linear Pearson correlation and nonlinear mutual information, we argue that the high sensitivity of betweenness with respect to small changes in network structure may allow to detect the footprints of strongly nonlinear physical interactions in the climate system. The results presented in this thesis are thoroughly founded and substantiated using a hierarchy of statistical significance tests on the level of time series and networks, i.e., by tests based on time series surrogates as well as network surrogates. This is particularly relevant when working with real world data. Specifically, we developed new types of network surrogates to include the additional constraints imposed by the spatial embedding of vertices in a climate network. Our methodology is of potential interest for a broad audience within the physics community and various applied fields, because it is universal in the sense of being valid for any spatially extended dynamical system. It can help to understand the localized flow of dynamical information in any such system by combining multivariate time series analysis, a complex network approach and the information flow measure betweenness centrality. Possible fields of application include fluid dynamics (turbulence), plasma physics and biological physics (population models, neural networks, cell models). Furthermore, the climate network approach is equally relevant for experimental data as well as model simulations and hence introduces a novel perspective on model evaluation and data driven model building. Our work is timely in the context of the current debate on climate change within the scientific community, since it allows to assess from a new perspective the regional vulnerability and stability of the climate system while relying on global and not only on regional knowledge. The methodology developed in this thesis hence has the potential to substantially contribute to the understanding of the local effect of extreme events and tipping points in the earth system within a holistic global framework.
Extreme habitats often harbor specific communities that differ substantially from non-extreme habitats. In many cases, these communities are characterized by archaea, bacteria and protists, whereas the number of species of metazoa and higher plants is relatively low. In extremely acidic habitats, mostly prokaryotes and protists thrive, and only very few metazoa thrive, for example, rotifers. Since many studies have investigated the physiology and ecology of individual species, there is still a gap in research on direct, trophic interactions among extremophiles. To fill this gap, we experimentally studied the trophic interactions between a predatory protist (Actinophrys sol, Heliozoa) and its prey, the rotifers Elosa woralli and Cephalodella sp., the ciliate Urosomoida sp. and the mixotrophic protist Chlamydomonas acidophila (a green phytoflagellate, Chlorophyta). We found substantial predation pressure on all animal prey. High densities of Chlamydomonas acidophila reduced the predation impact on the rotifers by interfering with the feeding behaviour of A. sol. These trophic relations represent a natural case of intraguild predation, with Chlamydomonas acidophila being the common prey and the rotifers/ciliate and A. sol being the intraguild prey and predator, respectively. We further studied this intraguild predation along a resource gradient using Cephalodella sp. as the intraguild prey. The interactions among the three species led to an increase in relative rotifer abundance with increasing resource (Chlamydomonas) densities. By applying a series of laboratory experiments, we revealed the complexity of trophic interactions within a natural extremophilic community.
Comprior
(2021)
Background
Reproducible benchmarking is important for assessing the effectiveness of novel feature selection approaches applied on gene expression data, especially for prior knowledge approaches that incorporate biological information from online knowledge bases. However, no full-fledged benchmarking system exists that is extensible, provides built-in feature selection approaches, and a comprehensive result assessment encompassing classification performance, robustness, and biological relevance. Moreover, the particular needs of prior knowledge feature selection approaches, i.e. uniform access to knowledge bases, are not addressed. As a consequence, prior knowledge approaches are not evaluated amongst each other, leaving open questions regarding their effectiveness.
Results
We present the Comprior benchmark tool, which facilitates the rapid development and effortless benchmarking of feature selection approaches, with a special focus on prior knowledge approaches. Comprior is extensible by custom approaches, offers built-in standard feature selection approaches, enables uniform access to multiple knowledge bases, and provides a customizable evaluation infrastructure to compare multiple feature selection approaches regarding their classification performance, robustness, runtime, and biological relevance.
Conclusion
Comprior allows reproducible benchmarking especially of prior knowledge approaches, which facilitates their applicability and for the first time enables a comprehensive assessment of their effectiveness
We shall examine the Pedagogical Content Knowledge (PCK) of Computer Science (CS) teachers concerning students’ Computational Thinking (CT) problem solving skills within the context of a CS course in Dutch secondary education and thus obtain an operational definition of CT and ascertain appropriate teaching methodology. Next we shall develop an instrument to assess students’ CT and design a curriculum intervention geared toward teaching and improving students’ CT problem solving skills and competences. As a result, this research will yield an operational definition of CT, knowledge about CT PCK, a CT assessment instrument and teaching materials and accompanying teacher instructions. It shall contribute to CS teacher education, development of CT education and to education in other (STEM) subjects where CT plays a supporting role, both nationally and internationally.