The Capital Sculpture of Wells Cathedral, c. 1184-1210

The understudied capital sculpture of Wells Cathedral in Somerset, England (c. 1184-1210) provides ample opportunity of expanding the current scholarship and understanding of interior ecclesiastical sculpture in a West Country cathedral. While the Gothic style of architecture is typically understood as, according to Paul Binski (2014), rational in execution and reception, the capital sculpture at Wells Cathedral has been considered illogical in terms of both its iconography and location within the nave, transepts, and north porch. Utilizing Michael Camille’s post/anti-iconographical approach, this project examines the Wells figural capitals in five case studies: labour, Old and New Testament Scenes, animals and beast fables, busts, and monsters and hybrids. Each group of capitals will be approached with an understanding that this type of art was viewed by people of different classes and professions, with each viewer bringing their own personal experiences and abilities into how they could have read and understood these types of images. Therefore, the capitals at Wells must be read through layers of meaning and interpretation while also considering their locations within the cathedral and how they react and respond to surrounding figural capitals.

Psychosocial Functioning in Women with Symptoms of Persistent Genital Arousal

Persistent genital arousal disorder (PGAD) is characterized by physiological sexual arousal (vasocongestion, sensitivity of the genitals and nipples) that is described as distressing, and sometimes painful. Although awareness of PGAD is growing, there continues to be a lack of systematic research on this condition. The vast majority of published reports are case studies. Little is known about the symptom characteristics, biological factors, or psychosocial functioning associated with the experience of persistent genital arousal (PGA) symptoms. This study sought to characterize a sample of women with PGA (Study One); compare women with and without PGA symptoms on a series of biopsychosocial factors (Study Two); and undertake an exploratory comparison of women with PGA, painful PGA, and genital pain (Study Three)—all within a biopsychosocial framework. Symptom-free women, women with PGA symptoms, painful PGA, and genital pain, completed an online survey of biological factors (medical history, symptom profiles), psychological factors (depression, anxiety) and social factors (sexual function, relationship satisfaction). Study One found that women report diverse symptoms associated with PGA, with almost half reporting painful symptoms. In Study Two, women with symptoms of PGA reported significantly greater impairment in most domains of psychosocial functioning as compared to symptom-free women. In particular, catastrophizing of vulvar sensations was related to symptom ratings (i.e., greater severity, distress) and psychosocial outcomes (i.e., greater depression and anxiety). Finally, Study Three found that women with PGA symptoms reported some overlap in medical comorbidities and symptom expression as those with combined PGA and vulvodynia and those with vulvodynia symptoms alone; however, there were also a number of significant differences in their associated physical symptoms. These studies indicate that PGA symptoms have negative consequences for the psychosocial functioning of affected women. As such, future research and clinical care may benefit from a biopsychosocial approach to PGA symptoms. These studies highlight areas for more targeted research, including the role of catastrophizing in PGA symptom development and maintenance, and the potential conceptualization of both PGA and vulvodynia (and potentially other conditions) under a general umbrella of ‘genital paraesthesias’ (i.e., disorders characterized by abnormal sensations, such as tingling and burning).

LINEUP SIZE AND NUMBER OF CUES: WHEN BIGGER ISN’T BETTER

Larger lineups could protect innocent suspects from being misidentified; however, they can also decrease correct identifications. Bertrand (2006) investigated whether the decrease in correct identifications could be prevented by adding more cues, in the form of additional views of lineup members’ faces, to the lineup. Adding these cues was successful to an extent. The current series of studies attempted to replicate Bertrand’s (2006) findings while addressing some methodological issues—namely, the inconsistency in image size as lineup size increased. First, I investigated whether image size could affect face recognition (Chapter 2) and found it could, but that it also affected previously-seen (“old”) versus previously-unseen (“new”) faces differently. Specifically, smaller image sizes at exposure lowered accuracy for old faces, while these same image sizes at recognition lowered accuracy for new faces. Although these results indicate that target recognition would be unaffected by image size at recognition (i.e., during a lineup), lineups are also comprised of previously-unseen faces, in the form of fillers and innocent suspects. Because image size could affect lineup decisions, as it could become more difficult to realize fillers are previously-unseen, I decided to replicate Bertrand (2006) while keeping image size constant in Chapters 3 (simultaneous lineups) and 4 (simultaneous-presentation, sequential decisions). In both Chapters, the integral findings were the same: correct identification rates decreased as lineup size increased from 6- to 24-person lineups, but adding cues had no effect. The inability to replicate Bertrand (2006) could mean that the original finding was due to chance, but alternate explanations also exist, such as the overall size of the array, the degree to which additional cues overlap, and the length of the target exposure. These alternate explanations, along with directions for future research, are discussed in the following Chapters.

‘Black Settlers’: Hybridity, Neoliberalism and Ecosystemic Change Among Tonga Farmers of Southern Zambia, 1964-2008

This dissertation examines a process of indigenous accumulation among Tonga farmers in Zambia’s Southern Province. In the 1970s multiple authors concluded that capitalist farmers had emerged among Tonga agro-pastoralists, predominantly within private titled holdings. Relying on archival research, newspapers, secondary sources and extensive oral testimony this thesis fills a 35-year gap on the topic, providing insights into the social and environmental impacts of neoliberal policy among African peasants and capitalist farmers. In contrast to dominant narratives of the post-independence period, this study argues that Zambia did experience a developmental process post-independence, which saw significant achievements made in the agricultural sector, including the doubling of national cattle stocks. The data reveals a painful process of disarticulation beginning in the late 1980s. Following neoliberal adjustment, we observe significant heterogeneity in production systems, some regional specialization, and processes of migration. Most importantly, the thesis uncovers processes of overwhelming ecosystemic change that contributed to livestock epidemics of severe scale and scope. Amazingly, this went largely undocumented because of the simultaneous crisis of the state, which left the national statistics office and other state bodies incapable of functioning from the late 1980s into the 2000s. In response, the Zambian state has introduced a number of neodevelopmental initiatives in the sector, yet the lack of animal traction remained up to 2008 and agricultural production declined, while more capitalized farmers (largely white, and/or with foreign direct investment) have become more significant players in the country. This thesis provides compelling evidence to challenge dominant economic thinking of the Washington institutions as well as many of the common Marxian formulations.

Analysis of the signal transduction in the hawk moth Manduca sexta

Fliegende Insekten orientieren sich in ihrer Umwelt mit Hilfe ihres hoch entwickelten olfaktorischen Systems. Es ermöglicht ihnen das Auffinden geeigneter Futter- und Eiablageplätze und ist unverzichtbar bei der innerartlichen Kommunikation. Der Geruchssinn muss dabei gleichzeitig sehr schnell und sensitiv sein um selbst geringste Mengen, z.B. des arteigenen Sexualpheromons, wahrnehmen zu können. Spezifische olfaktorische Rezeptoren (ORs) zur Detektion dieser Duftstoffe werden zusammen mit einem hoch konservierten Co-Rezeptor (Orco) in olfaktorischen Rezeptorneuronen (ORNs) auf den Insektenantennen exprimiert. Sie gehören zu den 7 Transmembran Rezeptoren, zeigen jedoch eine invertierte Membrantopologie im Vergleich zu den ORs der Vertebraten. Darüber hinaus bildet der OR/Orco-Komplex einen spontanaktiven Kationenkanal, die Bindung an ein G Protein ist allerdings umstritten. Daher ist noch ungeklärt, ob die Duftstoffbindung zu einer ionotropen Aktivierung des OR/Orco Kanals führt oder ob metabotrope Mechanismen die Bildung von zyklischem Adenosinmonophosphat (cAMP) oder Inositol 1,4,5-trisphosphat (IP3) bewirken. Mit Hilfe von extrazellulären Ableitungen einzelner Trichoidsensillen (tip recordings) auf den Antennen männlicher Manduca sexta wurde die Rolle von Orco sowie die Beteiligung einer Phospholipase Cβ (PLCβ)-abhängigen Transduktionskaskade untersucht. Es konnte gezeigt werden, dass die durch VUAA1 induzierte Spontanaktivität der ORNs durch OLC15 inhibiert und Orco somit kompetitiv gehemmt wurde. Eine Inhibition von Orco sollte die Antwort auf kurze Pheromonpulse sofort reduzieren, sollte die Transduktion über die Aktivierung des OR/Orco Kanals erfolgen. Die Ergebnisse dieser Arbeit zeigten jedoch keine Beeinflussung der primären Pheromonantwort, vielmehr wurde die späte, langanhaltende Antwort reduziert. Die ebenfalls als Orco-Antagonisten charakterisierten Amiloride MIA und HMA beeinflussen offensichtlich weitere Ziele, da eine substanz- und zeitgeberzeitabhängige Reduzierung der primären Antwort auftrat. Zusätzlich wurde die primäre Pheromonantwort durch die Inhibierung der PLCβ und der Proteinkinase C (PKC), sowie durch die Verwendung zweier Diacylglycerol (DAG)- Derivate signifikant beeinflusst. Hierbei zeigte die Inhibierung von PLCβ und PKC zeitgeberzeitabhängige Unterschiede in der Stärke der Antwortreduktion. Auch die Applikation des DAG-Derivates DOG reduzierte die Pheromonantwort, während die Zugabe von OAG die ORN Aktivität steigern oder reduzieren konnte, abhängig von der verwendeten Derivatkonzentration und der Pheromonkonzentration. Die Ergebnisse dieser Arbeit deuten somit auf einen metabotropen, sehr wahrscheinlich PLCβ-abhängigen Mechanismus für die Pheromontransduktion bei Manduca sexta.

Lambda_c detection using a weighted Bayesian PID approach

Lo scopo della tesi è di stimare le prestazioni del rivelatore ALICE nella rivelazione del barione Lambda_c nelle collisioni PbPb usando un approccio innovativo per l'identificazione delle particelle. L'idea principale del nuovo approccio è di sostituire l'usuale selezione della particella, basata su tagli applicati ai segnali del rivelatore, con una selezione che usi le probabilità derivate dal teorema di Bayes (per questo è chiamato "pesato Bayesiano"). Per stabilire quale metodo è il più efficiente , viene presentato un confronto con altri approcci standard utilizzati in ALICE. Per fare ciò è stato implementato un software di simulazione Monte Carlo "fast", settato con le abbondanze di particelle che ci si aspetta nel nuovo regime energetico di LHC e con le prestazioni osservate del rivelatore. E' stata quindi ricavata una stima realistica della produzione di Lambda_c, combinando i risultati noti da esperimenti precedenti e ciò è stato usato per stimare la significatività secondo la statistica al RUN2 e RUN3 dell'LHC. Verranno descritti la fisica di ALICE, tra cui modello standard, cromodinamica quantistica e quark gluon plasma. Poi si passerà ad analizzare alcuni risultati sperimentali recenti (RHIC e LHC). Verrà descritto il funzionamento di ALICE e delle sue componenti e infine si passerà all'analisi dei risultati ottenuti. Questi ultimi hanno mostrato che il metodo risulta avere una efficienza superiore a quella degli usuali approcci in ALICE e che, conseguentemente, per quantificare ancora meglio le prestazioni del nuovo metodo si dovrebbe eseguire una simulazione "full", così da verificare i risultati ottenuti in uno scenario totalmente realistico.

Funzioni BV e disuguaglianze isoperimetriche

All'interno della mia tesi verrà introdotta la teoria delle funzioni in R^{n} a variazione limitata (BV), seguendo le presentazioni di Lawrence C.Evans e Ronald F.Gariepy nel libro Measure Theory and Fine Properties of Functions e di Enrico Giusti nell'opera Minimal Surfaces and Functions of Bounded Variation. Le funzioni BV sono funzioni le cui derivate prime deboli sono misure di Radon, ossia misure di Borel regolari finite sui compatti. In particolare verranno anche analizzati gli insiemi E che hanno perimetro finito, ossia tali che la funzione indicatrice dell’insieme E sia una funzione BV. Nello specifico, nel primo capitolo verranno date le definizioni di funzioni BV e insiemi di perimetro finito, sia in una versione globale che in una locale, verrà enunciato un primo importante teorema per le funzioni BV e verrà analizzata la relazione tra funzioni di Sobolev e funzioni BV. Nel secondo capitolo, invece, verranno analizzate la semicontinuità inferiore, l'approssimazione con funzioni lisce e la compattezza di funzioni BV, mentre nel terzo capitolo verranno elencati alcuni risultati sulle funzioni BV riguardanti la Traccia, l'Estensione e la formula di Coarea. Infine, nel quarto ed ultimo capitolo, verranno studiate le disuguaglianze di Sobolev e Poincaré e le disuguaglianze isoperimetriche per funzioni BV.

Funzioni di Sobolev

In questa tesi cercherò di analizzare le funzioni di Sobolev su R}^{n}, seguendo le trattazioni Measure Theory and Fine Properties of Functions di L.C. Evans e R.F.Gariepy e l'elaborato Functional Analysis, Sobolev Spaces and Partial Differential Equations di H. Brezis. Le funzioni di Sobolev si caratterizzano per essere funzioni con le derivate prime deboli appartenenti a qualche spazio L^{p}. I vari spazi di Sobolev hanno buone proprietà di completezza e compattezza e conseguentemente sono spesso i giusti spazi per le applicazioni di analisi funzionale. Ora, come vedremo, per definizione, l'integrazione per parti è valida per le funzioni di Sobolev. È, invece, meno ovvio che altre regole di calcolo siano allo stesso modo valide. Così, ho inteso chiarire questa questione di carattere generale, con particolare attenzione alle proprietà puntuali delle funzioni di Sobolev. Abbiamo suddiviso il lavoro svolto in cinque capitoli. Il capitolo 1 contiene le definizioni di base necessarie per la trattazione svolta; nel secondo capitolo sono stati derivati vari modi di approssimazione delle funzioni di Sobolev con funzioni lisce e sono state fornite alcune regole di calcolo per tali funzioni. Il capitolo 3 darà un' interpretazione dei valori al bordo delle funzioni di Sobolev utilizzando l'operatore Traccia, mentre il capitolo 4 discute l' estensione su tutto R^{n} di tali funzioni. Proveremo infine le principali disuguaglianze di Sobolev nel Capitolo 5.

Role of catestatin as such as slowly released by fibronectin-coated pharmacologically active microcarriers (Fn-Pam) in limiting hypoxicinduced cell death

International audience

Development of procedures for the triazole fungicides determination in fruits and liquid samples using microextraction techniques and chromatographic separation

Agricultural crops can be damaged by funguses, insects, worms and other organisms that cause diseases and decrease the yield of production. The effect of these damaging agents can be reduced using pesticides. Among them, triazole compounds are effective substances against fungus; for example, Oidium. Nevertheless, it has been detected that the residues of these fungicides in foods as well as in derivate products can affect the health of the consumers. Therefore, the European Union has established several regulations fixing the maximum residue of pesticide levels in a wide range of foods trying to assure the consumer safety. Hence, it is very important to develop adequate methods to determine these pesticide compounds. In most cases, gas or liquid chromatographic (GC, LC) separations are used in the analysis of the samples. But firstly, it is necessary to use proper sample treatments in order to preconcentrate and isolate the target analytes. To reach this aim, microextraction techniques are very effective tools; because allow to do both preconcentration and extraction of the analytes in one simple step that considerably reduces the source of errors. With these objectives, two remarkable techniques have been widely used during the last years: solid phase microextraction (SPME) and liquid phase microextraction (LPME) with its different options. Both techniques that avoid the use or reduce the amount of toxic solvents are convenient coupled to chromatographic equipments providing good quantitative results in a wide number of matrices and compounds. In this work simple and reliable methods have been developed using SPME and ultrasound assisted emulsification microextraction (USAEME) coupled to GC or LC for triazole fungicides determination. The proposed methods allow confidently determine triazole concentrations of μg L‐1 order in different fruit samples. Chemometric tools have been used to accomplish successful determinations. Firstly, in the selection and optimization of the variables involved in the microextraction processes; and secondly, to overcome the problems related to the overlapping peaks. Different fractional factorial designs have been used for the screening of the experimental variables; and central composite designs have been carried out to get the best experimental conditions. Trying to solve the overlapping peak problems multivariate calibration methods have been used. Parallel Factor Analysis 2 (PARAFAC2), Multivariate Curve Resolution (MCR) and Parallel Factor Analysis with Linear Dependencies (PARALIND) have been proposed, the adequate algorithms have been used according to data characteristics, and the results have been compared. Because its occurrence in Basque Country and its relevance in the production of cider and txakoli regional wines the grape and apple samples were selected. These crops are often treated with triazole compounds trying to solve the problems caused by the funguses. The peel and pulp from grape and apple, their juices and some commercial products such as musts, juice and cider have been analysed showing the adequacy of the developed methods for the triazole determination in this kind of fruit samples.

Da organização e gestão do processo de treino e competição à análise das cargas por função na competição

Este trabalho consiste na elaboração do Relatório Final do Estágio Curricular, realizado como parte integrante e conclusiva do curso de Mestrado em Treino Desportivo pela Faculdade de Motricidade Humana. O Estágio desenvolveu-se no Real Sport Clube, nomeadamente no escalão de Juniores A na época de 2014/2015 tendo como objetivos favorecer a integração e consolidação, no contexto da prática, os conhecimentos teóricos adquiridos ao longo do curso. O presente relatório está estruturado em diferentes capítulos, ao longo dos quais se apresentam as atividades desenvolvidas durante o Estágio Curricular. O propósito é descrever e refletir sobre as atividades desenvolvidas ao longo da época, pretendendo-se realizar uma avaliação de todo o trabalho desenvolvido e os conhecimentos dele derivado, ao descrever e analisar criticamente as duas dimensões. O relatório tem inicio com uma revisão da literatura que suporta a prática profissional, composta por três áreas: a área 1 diz respeito à organização e gestão do processo de treino e competição, onde são abordadas as tarefas relativas à conceção dos ciclos de treino, condução das sessões e controlo da competição bem como algumas informações relativas ao plantel de Juniores A do RSC. Na área 2 é apresentado um estudo de investigação realizado com recurso a dispositivos GPS que nos apresenta resultados relativos às distâncias percorridas pelos diferentes atletas em jogos oficiais e por último, a área 3 ilustra os dois eventos realizados direcionados para a formação continua dos treinadores de futebol. O Estágio Curricular mostra-se, neste sentido, uma ótima oportunidade de aprendizagem e promotor da aquisição e desenvolvimento de competências profissionais e pessoais, de atitudes e resolução de problemas pedagógicos, por forma a constituir o ponto de partida para uma futura integração no mercado de trabalho.

As ROE na condução das Operações de Estabilização (não Artigo 5º - NA5CRO)

O presente Trabalho de Investigação Aplicada tem como tema “As ROE na condução das Operações de Estabilização (não Artigo 5º - NA5CRO)”. Atendendo à variedade de modalidades de intervenção, as forças multinacionais regem-se por Regras de Empenhamento. As Regras de Empenhamento implicam treino, em função da especificidade da Operação de Estabilização, enquadradas na gestão de crises. A investigação tem por objetivo saber qual o papel das Regras de Empenhamento nas Operações de Estabilização e a forma como estas são interpretadas e aplicadas pelas chefias militares em situações de intervenção em crises, com a presença de forças multinacionais, nomeadamente da ONU, NATO e UE. A metodologia adotada visa responder à pergunta central e, após a formulação desta, foram formuladas questões derivadas para encontrar possíveis respostas. O trabalho realizado fundamenta-se no levantamento bibliográfico, análise de documentos e realização de entrevistas. Através de uma amostra, realizaram-se entrevistas a chefias militares Portuguesas do Exército e da Marinha, que já se debruçaram sobre a problemática das Regras de Empenhamento, em termos teóricos e práticos, nomeadamente acerca do papel que lhes atribuem e a sua importância na concretização de um ambiente seguro e estável para as populações. A análise de conteúdo das entrevistas permitiu constatar que as chefias militares entrevistadas consideram relevante a existência e concomitante aplicação das Regras de Empenhamento. A investigação confirmou a importância das Regras de Empenhamento, como uma orientação para a ação e, sobretudo, como devem ser consideradas imprescindíveis para demarcar a limitação do uso da força, em questões de proporcionalidade e demais princípios que regem a aplicação de forças no âmbito do Direito Internacional Humanitário e dos Conflitos Armados (DIHCA). Verificou-se que a metodologia doutrinalmente aplicada nas Regras de Empenhamento, lhes confere suficientemente flexibilidade, não carecendo de atualização permanente, sendo utilizadas de acordo com tipologias específicas. Por último, releva-se a importância do treino militar, para que se conheçam os objetivos específicos das Operações de Estabilização em função da sua tipologia e a correspondente aplicabilidade das ROE.

Novel laser-induced luminescence resulting from benzophenone/O-propylated p-tert-butylcalix[4]arene complexes. A diffuse reflectance study

Laser-induced room temperature luminescence of air-equilibrated benzophenone/O-propylated p-tert-butylcalix[ 4] arene solid powdered samples revealed the existence of a novel emission, in contrast with benzophenone/p-tertbutylcalix[ 4] arene complexes, where only benzophenone emits. This novel emission was identified as phosphorescence of 1-phenyl-1,2-propanedione, which is formed as the result of an hydrogen atom abstraction reaction of the triplet excited benzophenone from the propoxy substituents of the calixarene. Room temperature phosphorescence was obtained in air-equilibrated samples in all propylated hosts. The decay times of the benzophenone emission vary greatly with the degree of propylation, the shortest lifetimes being obtained in the tri- and tetrapropylated calixarenes. Triplet - triplet absorption of benzophenone was detected in all cases, and is the predominant absorption in the p-tert-butylcalix[ 4] arene case, where an endo-calix complex is formed. Benzophenone ketyl radical formation occurs with the O-propylated p-tert-butylcalix[ 4] arenes hosts, suggesting a different type of host/guest molecular arrangement. Diffuse reflectance laser. ash photolysis and gas chromatography - mass spectrometry techniques provided complementary information, the former about transient species and the latter regarding the final products formed after light absorption. Product analysis and identification clearly show that the two main degradation photoproducts following laser excitation in the propylated substrates are 1-phenyl-1,2- propanedione and 2- hydroxybenzophenone, although several other minor photodegradation products were identified. A detailed mechanistic analysis is proposed. While the solution photochemistry of benzophenone is dominated by the hydrogen abstraction reaction from suitable hydrogen donors, in these solid powdered samples, the alpha-cleavage reaction also plays an important role. This finding occurs even with one single laser pulse which lasts only a few nanoseconds, and is apparently related to the fact that scattered radiation exists, due to multiple internal reflections possibly trapping light within non-absorbing microcrystals in the sample, and is detected until at least 20 mus after the laser pulse. This could explain how photoproducts thus formed could also be excited with only one laser pulse.

BODIPY-Porphyrazin-Hybride als panchromatische Lichtsammelsysteme für farbstoffsensibilisierte Solarzellen

In farbstoffsensibilisierten Solarzellen (DSSC) spielen Chromophore, die als Lichtsammel- und Energie-/Elektronentransfersysteme fungieren, eine zentrale Rolle. Phthalocyanine mit ihren intensiven Absorptionsbanden um 400 nm und 700 nm besitzen großes Potential für die effektive Sensibilisierung von Solarzellen. Trotz ihrer vielversprechenden physikochemischen Eigenschaften und intensiver Bemühungen erreichen Phthalocyanin-sensibilisierte Solarzellen nicht die Effizienzen, die bisher mit anderen Chromophorklassen erzielt werden konnten. In der vorliegenden Dissertation wurde die Entwicklung effizienter Lichtsammelsysteme für DSSC auf der Basis von Aza-substituierten Phthalocyaninen, sogenannten Pyrazinoporphyrazinen, verfolgt. Ein besonderer Fokus lag dabei auf einer Verbesserung der Absorptionseigenschaften der Chromophore im Bereich ihrer intrinsischen Absorptionslücke zwischen den Maxima um 400 nm und 700 nm. Um diese optische Lücke zu schließen wurden komplementär absorbierende BODIPY-Farbstoffe kovalent an synthetisch maßgeschneiderte Porphyrazine gebunden. Insgesamt wurden sechs neue Porphyrazin-Sensibilisatoren synthetisiert und photophysikalisch sowie elektrochemisch charakterisiert. Alle in dieser Arbeit untersuchten Porphyrazine tragen sterisch anspruchsvolle Tri(p-tolyl)propinyl-Gruppen um Agglomerationen zu vermeiden. Darüber hinaus wurden die Porphyrazine peripher entweder mit Hydroxy- oder Carboxygruppen als Bindungsstellen für oxidische Materialien ausgestattet sowie mit sechs BODIPY-Auxiliarfarbstoffen funktionalisiert, deren Substitutionsmuster variiert wurden. Zur Darstellung der komplexen Porphyrazine wurde eine Syntheseroute erarbeitet, die statistische Cyclisierungen unterschiedlicher Dinitril-Vorstufen beinhaltete und es ermöglichte, funktionelle Gruppen erst am vorgeformten Makrocyclus einzuführen. Die photophysikalische Untersuchung der hochfunktionalisierten Farbstoffe erfolgte über UV/Vis- und Fluoreszenzspektroskopie. Im Fall der BODIPY-Porphyrazin-Hybride schließt die zusätzliche Absorptionsbande der peripheren BODIPY-Einheiten die intrinsische Absorptionslücke der Porphyrazine. Die Hybride zeigen somit eine breite Absorption über den gesamten sichtbaren Spektralbereich mit hohen Extinktionskoeffizienten von ca. 4·10^5 M^−1cm^−1. Mittels Fluoreszenz- und Anregungsspektren wurde ein photoinduzierter Energie-transfer von den BODIPY-Einheiten auf den Porphyrazinkern nachgewiesen. Das elektrochemische Verhalten der BODIPY- und Porphyrazin-Verbindungen wurde mittels Cyclo- und Square-Wave-Voltammetrie untersucht. Die Effizienzen der Lichtenergieumwandlung wurden mit Hilfe von selbst-hergestellten und standardisierten farbstoffsensibilisierten Solarzellen bewertet. Alle Solarzellen zeigten eine messbare Photoaktivität unter Bestrahlung. Die Wirkungsgrade der Zellen lagen jedoch alle unter 1 %. Generell führten die Carboxyl-funktionalisierten Porphyrazine zu besseren Wirkungsgraden als die analogen, mit der tripodalen Ankergruppe ausgestatteten Derivate. Die mit Hilfe von Adsorptionsisothermen ermittelten Bindungskonstanten der Adsorption der Farbstoffe auf der TiO2-Oberfläche zeigten, dass beide Hafteinheiten eine feste Verankerung der Chromophore auf den TiO2-Elektroden ermöglichten. Insgesamt wirkte sich die Präsenz der peripheren BODIPY-Farbstoffe positiv auf die Wirkungsgrade der Solarzellen aus, jedoch nur in geringem Maß. Dieses Ergebnis wurde hauptsächlich auf die geringe Energiedifferenz zwischen der Leitungsbandkante des TiO2 und den LUMO-Energieniveaus der Chromophore zurückgeführt. Zusätzlich scheinen konkurrierende Prozesse wie die direkte Photoelektroneninjektion von den BODIPY-Einheiten in das TiO2 eine wichtige Rolle zu spielen. Neben der Anwendung in DSSC wurde die Wechselwirkung der Porphyrazine mit Graphen untersucht. Hierzu wurden A3B-Porphyrazine mit Pyrenyl-Seitenketten ausgestattet, die eine nicht-kovalente Verankerung des Chromophors auf Graphen ermöglichen. UV/Vis- und Fluoreszenzmessungen gaben u.a. erste Hinweise auf eine elektronische Kommunikation zwischen den beiden Hybridpartnern.

Nitrogen use efficiency and optimization of nitrogen fertilizer application for stable yields and high quality of cereals grown in conservation agriculture

In most agroecosystems, nitrogen (N) is the most important nutrient limiting plant growth. One management strategy that affects N cycling and N use efficiency (NUE) is conservation agriculture (CA), an agricultural system based on a combination of minimum tillage, crop residue retention and crop rotation. Available results on the optimization of NUE in CA are inconsistent and studies that cover all three components of CA are scarce. Presently, CA is promoted in the Yaqui Valley in Northern Mexico, the country´s major wheat-producing area in which from 1968 to 1995, fertilizer application rates for the cultivation of irrigated durum wheat (Triticum durum L.) at 6 t ha-1 increased from 80 to 250 kg ha-1, demonstrating the high intensification potential in this region. Given major knowledge gaps on N availability in CA this thesis summarizes the current knowledge of N management in CA and provides insights in the effects of tillage practice, residue management and crop rotation on wheat grain quality and N cycling. Major aims of the study were to identify N fertilizer application strategies that improve N use efficiency and reduce N immobilization in CA with the ultimate goal to stabilize cereal yields, maintain grain quality, minimize N losses into the environment and reduce farmers’ input costs. Soil physical and chemical properties in CA were measured and compared with those in conventional systems and permanent beds with residue burning focusing on their relationship to plant N uptake and N cycling in the soil and how they are affected by tillage and N fertilizer timing, method and doses. For N fertilizer management, we analyzed how placement, time and amount of N fertilizer influenced yield and quality parameters of durum and bread wheat in CA systems. Overall, grain quality parameters, in particular grain protein concentration decreased with zero-tillage and increasing amount of residues left on the field compared with conventional systems. The second part of the dissertation provides an overview of applied methodologies to measure NUE and its components. We evaluated the methodology of ion exchange resin cartridges under irrigated, intensive agricultural cropping systems on Vertisols to measure nitrate leaching losses which through drainage channels ultimately end up in the Sea of Cortez where they lead to algae blooming. A throughout analysis of N inputs and outputs was conducted to calculate N balances in three different tillage-straw systems. As fertilizer inputs are high, N balances were positive in all treatments indicating the risk of N leaching or volatilization during or in subsequent cropping seasons and during heavy rain fall in summer. Contrary to common belief, we did not find negative effects of residue burning on soil nutrient status, yield or N uptake. A labeled fertilizer experiment with urea 15N was implemented in micro-plots to measure N fertilizer recovery and the effects of residual fertilizer N in the soil from summer maize on the following winter crop wheat. Obtained N fertilizer recovery rates for maize grain were with an average of 11% very low for all treatments.