Bøger udgivet af Cuvillier

W.B. Yeats: Realms of the Romantic Imagination shows us how Yeats¿s unorthodox approaches to poetic meaning, especially within modernist poetry, are part of the how the poet ¿astonishes¿ his contemporary readers. By astonishment, I refer to the Aesthetics of the Canon in which Frank Kermode explains how each generation of reader must always discover anew the wonder of transcendent meaning in poetry. What John Nkemngong Nkengasong does here is demonstrate how Yeats ultimately adhered to forms of creativity more aligned with Romanticism, undergirded with the sense of transcendence that is part of poetry itself and not necessarily part of the wider forms of belief which modernism engages and perhaps battles.

The focus of this work was on fathers across the transition to fatherhood. The purpose of theempirical studies was to explore the association of testosterone (T) and paternal investmentincluding interpersonal differences in personality traits and relationship quality. Providingpaternal care is associated with a reduced likelihood of engaging in competitive or matingbehavior and also of providing protection when necessary. T is a psychobiological marker ofreproductive behavior.Recent studies found decreasing T levels in males across the transition to fatherhood, inorder to reduce mating effort in favor of providing paternal care. In addition, there is empiricalevidence for reducing relationship quality in parents across the transition to parenthood.Therefore, a direct association of T level and relationship quality was suggested. Moreover,researchers have assumed that sensation seeking (SS) is associated with both mating effortand T. For this reason, the personality trait SS was included in further investigations of thesecond study of this work.Thirty-seven fathers and 38 men in committed romantic relationships without children(controls) were recruited. On two days (four weeks prior to (t1) and eight weeks after birth(t2) for fathers, and three months after the first measurement day for controls), all subjectsrepeatedly collected saliva samples for T measurement at three times of the day, filled in aprotocol of activities and completed online questionnaires.

Novel functionalized rare earth metal clusters and polymers have been prepared, characterized and investigated with respect to various potential applications.The literature known tetra- and pentanuclear rare earth metal hydroxy clusters [Ln4(?3-OH)2(Ph2acac)10] (Ln = Pr, Nd, Sm) and [Ln5(?4-OH)(?3-OH)4(Ph2acac)10] (Ln = Y, Eu) were embedded into different polymer matrices applying the miniemulsion polymerization technique to give cluster-polymer hybrid nanocompounds with narrow size distributions. The polymer matrices involved were composed of polystyrene (PS), poly(methyl methacrylate) (PMMA), poly(lauryl methacrylate) (PLMA) and poly(butyl acrylate-co-methyl methacrylate) (PBA-co-MMA). As a consequence of encapsulation, aqueous dispersions containing the hydrophobic clusters with more than 1000 mg¿L-1 could be prepared. Subsequent optical investigations revealed the retention of the encapsulated clusters¿ photophysical properties in aqueous dispersions. Additionally, a very efficient energy transfer from the ligand and polymeric unit to the Eu3+-ions was observed.Envisioning a functionalization of these pure Ph2acac clusters, the pentanuclear mixed ligated rare earth metal hydroxy clusters [Ln5(?4-OH)(?3-OH)4(??AA)4(Ph2acac)6] (1-6) (Ln = Y: ??AA = D-PhGly (1), L-Pro (2), L-Val (3), L-Trp (4), Ph2Gly (5); Ln = Dy: ??AA = D-PhGly (6)) were reproducibly prepared in gram scale and the corresponding solid state structures were established via single crystal X-ray analysis. Clusters 1-6 display a square pyramidal {Ln5(?4-OH)(?3-OH)4}10+ scaffold, which is coordinatively and electronically saturated by six chelating Ph2acac ligands and four amino acid ligands acting as bridging chelates. The hydrodynamic radius rH of valine cluster 3 was determined via NMR-based PGSE diffusion experiments, revealing the retention of the cluster¿s scaffold upon dissolution. Furthermore, 2D NMR experiments with 3 showed a heteronuclear cross coupling between 89Y and 1H nuclei.

This study is dedicated to the preservation of the heritage of the Modern Movement,particularly through improving the structural response to seismic solicitations, which arecommon in some of the areas where significant works in this style can be found,including Bucharest, Romania. The focus is on developing and validating methodologyaccording to which the vulnerability of ¿interwar¿ buildings, which is the other namegiven to the blocks of flats which witnessing the Modern Movement in the Romaniancapital. To complement this study with a geographical generalisation, the modelsproposed have been also tested for selected earthquakes, taking into account that theModern Movement left its traces in form of that very characteristic blocks of flats thereas well.

This work deals with geometric problems and the use of limited capability agents for these problems. Exploration and guarding problems have been extensively studied in computational geometry. The basic task is to monitor an environment (a polygon) either with a mobile guard or with a number of sta¬tionary guards (or guards with hard restrictions on the allowed movements). Though all these problems are easy to formulate¿and have real-world interpretations that vividly illustrate them¿some of these problems (as the classical art gallery problem) are hard to solve. The task of exploring an environment becomes more challenging if the environment is not known in advance, that is, there is no given ground plan and only areas that have already been visibly encountered by the explorer are known. Problems with this kind of uncertainty are called online problems. For öine problems the ground plan of the environment is known in advance. In this work we study one öine exploration problem and one exploration and guarding problem in the öine and online version, where the focus is on the latter. For our problems we do not deal with ¿almighty¿ explorers, but face limits on their perceptive capabilities. Other types of geometric problems can exploit this kind of limited agents: We present an exact and fast algorithm for an image analysis task with polyomino-shaped objects on a grid.

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The quality and application of nanostructured materials are strongly related to particle and powder characteristics. Powders of small particle size, narrow size distribution, low degree of agglomeration and high purity are typically required for the fabrication of solid nanocrystalline materials and the exploitation of size effects in applications. Chemical vapor synthesis (CVS) is a method for the generation of nanoparticles in the gas phase. Process parameters (temperature, pressure, residence time, precursor concentration, etc.) play an important role.In this work it is shown for TiO2 that the way in which energy is supplied to the reactor and the time-temperature history which the particles experience have sub-stantial influence on the particle generation and powder characteristics. The de-gree of agglomeration can be decreased by using high process temperatures and high quenching rates. A novel method, pulsed precursor delivery using a laser flash evaporator, was developed to feed precursors into a CVS reactor. The degree of particle agglomeration can be significantly reduced by pulsed precursor deli-very. The volatility of precursors used in CVS can limit the number of possible material systems which can be produced as well as their production rate. It is shown that these limitations can be overcome by the use of a laser flash evapora-tor, which enables the production of complex oxides such are Co-doped and Co, Li-doped ZnO. A high solubility of Co in ZnO, where Co is substituting Zn in the wurtzite lattice is achieved. This is the key requirement for the development of di-lute magnetic semiconductors based on Co-doped ZnO.

Amphiphilic molecules spontaneously self-assemble into a variety of structures in solution. The term amphiphilic indicates that one part of the molecule is attracted to the solvent, while the other is not. Interactions such as between solute-solvent and solute-solute thus determine the organization. Understanding the self-assembly means understanding those interactions and their driving forces. In the first chapter an overview of the self-organization of amphiphilic molecules into supermolecuar aggregates of different morphologies is provided, with a focus on purely peptidic amphiphiles, i.e. amphiphiles which consist solely of a different amino acid sequence. In the second chapter the self-assembly of amphiphilic peptides with a specific amino acid sequence into micelles and spherical peptide nanoparticles is described. The undecamer peptide that was used features a repetitive L-tryptophan and D-leucine [LW-DL] motif, representing the hydrophobic block ¿ which is a truncated version of gramicidin A (gA), named gT. The N-terminally attached hydrophilic section was either lysine (K) or acetylated lysine (X) and was optionally terminated with cysteine for post-functionalization of the thiol-group. The uncharged peptide AcC-X3-gT was demonstrated to assemble into micelles and subsequently into peptide particles, termed ¿peptide beads¿. We hypothesize that the peptide beads consisted of micelles ¿ a structure described as multicompartment micelles. Peptide beads using AcC-X3-gT and its analogues ¿ including Ac-X3-gT-C, a new peptide with the cysteine residue on the C instead of the N-terminus ¿ are further investigated in Chapter Three. We succeeded in creating highly ordered Ac-X3-gT-C ¿ Au-NP composites, which allowed us to visualize the inner structure of the nanoparticles. The presented composite materials are expected to exhibit exceptional electrical and optical properties.

This book consists of, apart from the introduction, the chapters- DA Stochastic Dynamic Programming with Random Disturbances,- The Problem of Stochastic Dynamic Distance Optimal Partitioning(SDDP problem),- Partitions-Requirements-Matrices (PRMs).DA (¿decision after¿) stochastic dynamic programming with random disturbances¿is characterized by the fact that these random disturbances are observedbefore the decision is made at each stage. In the past, only very moderateattention was given to problems with this characteristic.In Chapter 2 specific properties of DA stochastic dynamic programming problemsare worked out for theoretical characterization and for more efficientsolution strategies of such problems.The (DA) Stochastic Dynamic Distance Optimal Partitioning problem(SDDP problem) is an extremely complex Operations Research problem. Itshows several connections with other problems of operations research andinformatics such as stochastic dynamic transportation and facility locationproblems or metric task systems and more specific k-server problems.Partitions of integers as states of SDDP problems require an enormousamount of storage space for the corresponding computer programs. Investigationsof inherent characteristic structures of SDDP problems are also importantas a basis for heuristics.Partitions-requirements-matrices (PRMs) (Chapter 4) are matrices of transitionprobabilities of SDDP problems which are formulated as Markov decisionprocesses. PRMs ¿in the strict meaning¿ include optimal decisions ofcertain reduced SDDP problems, as is shown (in many cases) toward the endof the book.PRMs (in the strict meaning) themselves represent interesting (almost selfevident)combinatorial structures, which are not otherwise found in literature.In order to understand the investigations of this book, previous knowledgeabout stochastic dynamic Programming and Markov decision processes isuseful, however not absolutely necessary since the concerned models aredeveloped from scratch.

This book presents an experimental approach in aquatic ecology on the level of organism, population and ecosystem. Principles of the experiments are energy flow and transformation of the organic matter. The book consists of five chapters. The first four chapters have the same structure. They begin with the shot introduction, then there are methods of investigations, in the other parts of the each chapter are descriptions of results and they are finalized by a paragraph ¿Tests and exercises¿. The main results are presented in quantitative form as equations between the studying process and body mass, temperature and other environmental factors.Chapter 1 concentrates on concepts of experimental ecology, on energy balance, its means of expression and on units of measurement of the balance equality. Chapter 2 is devoted to the role of animal respiration in the mineralization of organic matter. Summarized data have given a possibility to compare the metabolic rate of different representatives of animal kingdom from one cell organisms to the vertebrata.In the chapter 3 are described growth, development and production of aquatic animals, types of their somatic growth, generative growth and its relation to the energy metabolism. The subject of the chapter 4 is quantitative concepts of animal feeding.

Dimethyl ether is one of the largest organic molecules detected in the interstellar medium. It is highly abundant in star forming regions. As an asymmetric top molecule with two methyl groups which undergo large amplitude motions and a moderately large dipole moment, it conveys a dense spectrum throughout the terahertz region and contributes to the spectral line confusion in astronomical observations at these frequencies.In the scope of this thesis, the rotational spectrum of dimethyl ether has been investigated by means of high resolution spectroscopy in order to improve the understanding of the internal rotation dynamics and to provide comprehensive datasets for astronomical applications. Spectra have been recorded up to 2.1 THz. Their analysis allowed to provide accurate frequency predictions for astronomical applications, which enabled the first interstellar detection of transitions within excited torsional states of dimethyl ether.An important prerequisite for these measurements was the development of a new spectrometer, which extends the frequency coverage of the Cologne spectrometers considerably. This has been realized by the application of a novel type of frequency multiplier, a superlattice multiplier. High multiplication factors and frequencies up to 3.1 THz have been achieved and used to record spectra of rotational transitions of various molecules. Due to these properties these devices are also well suited as mixer elements in heterodyne receivers. This has been proved by the assembly of a heterodyne receiver working at room-temperature. Further investigations using extremely sensitive THz-heterodyne receivers have been carried out in order to explore their potential in scope of future applications.

In der vorliegenden Dissertation wurden neue Erkenntnisse auf dem Gebiet der experimentellen Erforschung der Korngrenzenbewegung vorgestellt. Im Rahmen der Arbeit wurde anhand von in-situ Messungen mittels einer eigens dazu entwickelten Polarisationsmikroskopiesonde mit integriertem Heiztisch die Abhängigkeit der Korngrenzenbeweglichkeit vom Desorientierungs- und Inklinationswinkel der Korngrenze, sowie der Temperatur an speziell gezüchteten Bikristallen aus 99,995% Zink mit symmetrischen und asymmetrischen Kippkorngrenzen und gemischten Korngrenzen im Temperaturbereich zwischen 330°C und 415°C in Hochmagnetfeldern von 10 bis 28 Tesla Stärke als Triebkraft untersucht. Dabei wurde die jeweilige Wanderungsgeschwindigkeit v der Korngrenzen bei verschiedenen Temperaturen und treibenden Kräften gemessen. Aus den so erhaltenen Messdaten wurden die Aktivierungsparameter der Korngrenzenbewegung für die jeweils untersuchte Korngrenze bestimmt.Weiter wurde im Rahmen der Experimente in Hochfeldmagneten gezeigt, dass die Polarisationsmikroskopiesonde zur Bestimmung der Korngrenzenenergie in magnetisch anisotropen Metallen verwendet werden kann. Zu kleinerem Anteil wurden auch Versuche zu krümmungsgetriebener Korngrenzenbewegung durchgeführt.Alle Ergebnisse zeigten eine starke Inklinations- und Desorientierungsabhängigkeit der Korngrenzenbeweglichkeit, wobei für asymmetrische Korngrenzen höhere Aktivierungsparameter ermittelt wurden als für symmetrische. Dies wurde auf Unterschiede zwischen der atomistischen Struktur von asymmetrischen und symmetrischen Korngrenzen zurückgeführt. Weiterhin wurde auch die Auswirkung einer Glühung im Hochmagnetfeld auf Textur- und Mikrostrukturentwicklung von Zinkpolykristallen untersucht, wobei gezeigt wurde, dass das Magnetfeld ein geeignetes Werkzeug zur Beeinflussung der Mikrostruktur in Zink ist.

For the first time, 1,5-diaminopentane (polyamide monomer) production from xylose was achieved by a recombinant Corynebacterium glutamicum strain. Via rational metabolic engineering the product yield was increased by 54% and the productivity by 100%. The tailor-made strain finally accumulated 103 g L-1 diaminopentane in a fed-batch fermentation, the highest titer ever obtained on xylose. In a two-step process hemicellulose was used as substrate. The monosaccharides were first obtained by hydrolysis and then further used as substrate for the production of1,5-diaminopentane. Another resource tested was black liquor, a major industrial waste from pulp and paper manufacturing. It turned out that pre-treatment of the black liquor is necessary to obtain bioavailable sugars for subsequent production. The optimized C. glutamicum strain grew well on the black liquor hydrolysate and efficiently converted the containing carbon into 1,5-diaminopentane. The achieved product yield was about 120 % higher than on pure xylose. In this regard, the present work displays a milestone in industrial strain- and bioprocess engineering of C. glutamicum.Die Herstellung des Polyamidmonomers, 1,5-Diaminopentan, aus Xylose, wurde in dieser Arbeit zum ersten Mal, mit Hilfe eines rekombinanten Corynebacterium glutamicum Stammes realisiert. Durch gezieltes Metabolic Engineering konnte die Ausbeute des Stammes um 54%, die Produktivität um 100 % gesteigert werden. In einer Fed-Batch Fermentation wurde mit diesem maßgeschneiderten Stamm 103 g L-1 Diaminopentane, die höchste jemals erreichte Konzentration auf Xylose, produziert. In einem zweistufigen Prozess wurde anschließend Hemicellulose als Substrat für die Produktion eingesetzt. Die Monosaccharide wurden dabei zunächst in einer enzymatischen Hydrolyse aus der Hemicellulose gewonnen und für die biotechnologischen Produktion von 1,5-Diaminopentan eingesetzt. Als weiterer Rohstoff wurde Schwarzlauge, ein industrieller Abfallstoff aus der Papierindustrie, als Substrat eingesetzt. Es stellte sich heraus, dass eine Vorbehandlung der Schwarzlauge notwendig ist, um die Zucker für die darauf folgende Produktion verfügbar zu machen. Der optimierte C. glutamicum Stamm war in der Lage den Kohlenstoff aus dem Schwarzlauge Hydrolysat zu verstoffwechseln und effizient 1,5-Diaminopentane, mit einer um 120 % gesteigerten Produktausbeute, zu produzieren. Die vorliegende Arbeit repräsentiert daher einen Meilenstein der industriellen Stamm- und Bioprozessentwicklung von Corynebacterium glutamicum.

In this study the impacts of temperature and moisture on the warpage of molded plastic packages were investigated.The investigation started with material characterizations. The influences of post-mold cure, reflow soldering, temperature cycles and high temperature storage on the material parameter (Young¿s modulus, coefficient of thermal expansion and glass transition temperature) of the investigated Epoxy Molding Compound (EMC) were investigated.By using test specimens (bi-material systems composed of EMC and copper, EMC and silicon) as well as real molded plastic packages (QFN packages), it was shown how material parameter changes due to thermal aging of EMC can lead to warpage changes of molded plastic packages.The impact of thermal aging on the structural changes of EMC was investigated. The oxidation layer, which developed on the surfaces of EMC due to thermal aging, was characterized. The formation of a second glass transition temperature in EMC due to thermal aging was investigated as a function of storage time and storage temperature.In the last chapter of this study, the simultaneous impact of temperature and moisture on the warpage of molded plastic packages was investigated by means of experiments and simulations.This study provides a deep understanding of warpage changes and stress changes respectively in molded plastic packages, when these are subjected to reflow soldering, temperature cycles, high temperature storage and moisture.

The demand pressure and the plethora of evidences observed in the form of increasing infrastructure financing gap, ageing infrastructure, environmental factors, such as climate change and rising quality standards are factors attracting institutional and private sector participation in infrastructure investment. Therefore, the search for innovative means of financing infrastructure has become incessant. Also, the features of the financial landscape, especially in a financial crisis has further underpinned the significance of looking beyond the present infrastructure need, to a more sustained infrastructure financing scheme anticipated from institutional investors.A well established capital market has therefore been identified as a viable option for long term and steady global capital flows to financing infrastructure projects; else, the burden will remain on governments to offer direct or indirect support to private investors in attracting financing for infrastructure development. This book therefore conceptually investigates the potentials of the capital market and institutional investors¿ capital flows in bridging the global infrastructure funding gap. A fundamental conclusion from the book revealed that institutional investors particularly pension funds have the capacity to pool enormous resources into the infrastructure market, thus emphatically projecting them as a force to be reckoned with in the global infrastructure investments.

The growing energy consumption of lighting as well as rising luminous efficacies and -fluxes of high-power Light Emitting Diodes (LEDs) have contributed to the widespread use of LEDs in modern lighting systems. One of the most prominent users of the LED-technology is automotive (exterior) lighting. It benefits from LEDs¿ high efficiencies and long lifetimes, but furthermore uses their small size as key feature to obtain new degrees of freedom in placing light elements. Although automotive LED-lighting is at the leading edge regarding 3D LED-lighting systems, their current construction is not optimised towards complex design requirements.This thesis deals with decreasing the complexity and improving the degrees of freedom in the design of three-dimensional high-power LED-lighting systems with power electronic LED-driver by enhancing the level of function integration. Three main challenges are identified for the proposed concept and are investigated throughout the thesis. These are the integration of the power electronic LED-driver, of spatial ¿ and electrical-functions as well as of thermal management functions into the three-dimensional multifunctional component.

In the course of this thesis, two different molecular species have been studied. Both are connected to different aspects of rotational spectroscopy regarding the challenges in the investigation as well as the scientific questions.Oxatrisulfane (HSSOH) is a molecule of chemical interest with the focus on obtaining the geometric structure and the stability of possible configurations of oxasulfanes. Since it is a very reactive molecular species, which is not stable even under laboratory conditions, the production of oxatrisulfane is the bottleneck to a spectroscopic investigation.The 13C-isotopologues of dimethyl ether (13CH3O12CH3 and (13CH3)2O) are stable molecules, but the analysis of their rotational spectrum is challenging due to large amplitude motions of the two methyl groups. The development of spectroscopic models for molecules undergoing internal rotation is still ongoing, involving combined theoretical and experimental efforts. In addition, isotopologues of dimethyl ether are of strong astronomical interest. Precise prediction of their rotational spectrum is essential to overcome the line confusion in astronomical observations of star-forming regions and to enable the detection of more exotic species. Furthermore, the relative isotopic abundance ratios of molecular species in the interstellar medium can contain information on their formation processes. These ratios are important pieces in the big puzzle of astrochemical networks which aim towards the understanding of the evolution of star-forming regions.

For the highly accurate calculation of orbit and attitude dynamics for dedicated scientific satellite missions a multi-purpose tool is developed. The range of applications given by the modular approach including a diversity of models and tools allows spanning the bridge between multiple engineering and science tasks. Application includes all mission phases such as spacecraft design, system verification, disturbance estimation and science signal modeling. Its high gravitational detail faithfully reflecting Earth¿ gravity anomalies and comprehensive environmental modeling has made the simulator particularly useful for application to science missions aiming to measure very small signals that easily can be falsified by effects that are not quantified with high precision. A strong focus is also laid on highly accurate modeling for the resolution of coupling interaction in a multi-body dynamics system. The current application includes post-mission data analysis of the science mission Gravity Probe B for validation purpose. The verification with science data represents the ultimate test towards simulator reliability and accuracy.

The Inverse Fan-beam (IF) confi guration for X-ray Diffraction Imaging (XDI) and its capability of identifying liquid and amorphous substances for the purpose of explosive detection are described and investigated. Material specifi c information can be obtained by measuring x-ray diffraction profi-les from selected volume elements within inhomogeneous extended objects. This new technique can be used to fi ngerprint liquid explosives and may eliminate the inconvenience, uncertainty, and expense associated with monitoring liquids separately from hand luggage at airport checkpoints. Design concepts for multi-detector arrangements, a multidirectional primary collimator and the scatter imaging collimator are presented and evaluated using numerical procedures.A computer program using ray-tracing methods is described for calculating the primary beam profi le, the scattering angle distribution, and the radiation effi ciency with respect to the x-ray collimation geometry. Synchrotron x-ray diffraction measurements were performed on various liquids which are of interest for security applications. The diffraction profi les are presented and the key features which are potentially suitable for the purpose of explosive detection identifi ed. Material specific information is obtained about the morphology and its effective atomic number.Several additional parameters describing the structure and density of the object under investigation can be derived from the peaks in the molecular interference function.

Das Ziel der Arbeit bestand darin, die lokalen und globalen mechanischen Beanspruchungsparameter in einem Rührkesselbioreaktor mit Hilfe der numerischen Strömungssimulation (CFD) nachzubilden und die Ergebnisse mit experimentellen Daten der Pellet-kultivierung bzgl. Fluiddynamik und Rheolgie des rekombinanten Stammes A. niger SKAn1015 zu validieren.Ausgehend von der einphasigen Strömungssimulation eines 2L-Bioreaktors werden zunächst Simultionsdaten über Strömungsgeschwindigkeit und mechanische Beanspruchung diskutiert. Aßerdem erfolgt eine Validierung der einphasigen Simulationsdaten mit der Particle Image Velocimetry. In weiteren Untersuchungen wird die Strömungssimulation auch auf nicht-newtonsche Flüssigkeiten, so wie sie bei der Kultivierung filamentöser Pilze üblicherweise auftreten, mit dem Ostwald ¿ de Waele-Ansatz erweitert und die mechanische Beanspruchung in Abhängigkeit zu den rheologischen Prozessparametern korreliert. Die Untersuchung des Einflusses unterschiedlicher Rührergeometrien auf die Strömungsfelder und die mechanische Beanspruchung mittels CFD bildet den Abschluss, so dass die Auswahl eines geeigneten Rührers für den Kultivierungsprozess mit schesensitiven biologischen Systemen eindeutig getroffen wird.Die Arbeit validiert die numerische Strömungssimulation in einem Bioreaktor mit experimentell gnerierten biologischen und fluiddynamischen Prozessdaten und gibt praktische Hinweise darüber, wie biotechnologische Prozesse mit filamentösen Mikroorganismen hinsichtlich der Minimierung der mechanischen Beanspruchung zu betreiben sind.

Die Mikronährstoffe Fe und Zn werden von Samen für die Entwicklung des Keimlings benötigt. Getreidekörner besitzen geringe Fe und Zn Gehalte und sind deshalb eine schlechte Quelle dieser Mikronährstoffe für die menschliche Ernährung.Um eine Anreicherung von Mikronährstoffen in Getreidekörnern zu erreichen, müssen jene aufgenommen, von der Wurzel zu Blättern oder Stängeln transloziert und von seneszenten Blättern oder Stängeln in die sich entwickelnden Körner retransloziert werden. Es ist bekannt, dass Stickstoffernährung eine wichtige Rolle bei der Retranslokation von Mikronährstoffen spielt, da die Anregung der Synthese von N-haltigen Fe Chelatoren wie Nikotianamin und Phytosiderophoren zu einer erleichterten Langstreckentranslokation dieser Metalle führen kann. Andererseits könnte eine N Düngung auch entgegengerichtet wirken, da dadurch Seneszenz verzögert wird und Mikronährstoffe in vegetativen Organen festgehalten werden. Bisher wurden die meisten Studien zu Mirkronährstoffretranslokation während der Blattseneszenz in hydroponischer Kultur oder in Topfexperimenten durchgeführt. Die hier vorliegende Arbeit untersuchte deshalb den Effekt unterschiedlicher N Düngungsformen auf Blattseneszenz und Mikronährstoffanreicherung in Weizenkörnern (Triticum aestivum cv. Akteur) unter Feldbedingungen in zwei aufeinanderfolgenden Jahren. Es wurde beobachtet, dass die Seneszenz des Fahnenblattes durch N Düngung verzögert war und zwar besonders dann, wenn N in Form von Nitrat oder Ammonium angeboten wurde, wohingegen Harnstoff weniger effektvoll war. In beiden Feldexperimenten führte die Zugabe von Ammonium nach der Blüte zu einem erhöhten Fe und Zn Gehalt in den Körnern. Dies lässt darauf schließen, dass diese Behandlung eine vielversprechende Strategie zur verbesserten Anreicherung dieser Mikronährstoffen in Weizenkörnern darstellt. Die Stickstoffversorgung führte auch zu erhöhten Nikotianamingehalten in Blättern und Blattexudaten, wohingegen die Phytosiderophorkonzentrationen weit weniger vonden N Behandlungen beeinflusst waren. In einem Versuch die Fe und Zn Mobilisierung zu verbessern wurde Zitrat auf seneszierende Blätter von Freilandweizen gesprüht und die Mikronährstoffanreicherung in den Körnern gemessen. In N-gedüngten Pflanzen erhöhte die Zitratapplikation die Zitratexudation von seneszierenden Blättern nicht und die Fe und Zn Anreicherung in Körnern blieb unverändert. In ungedüngten Pflanzen hingegen erhöhte die Zitratapplikation die Zitratgehalte in den Exudaten seneszenter Blätter und führte zu signifikant erhöhten Fe Gehalten in den Körnern. In diesem Fall ist der positive Effekt der Zitratapplikation höchstwahrscheinlich auf eine verbesserte Fe Solubilisierung durch Zitrat in den Fahnenblättern zurück zu führen, da diese Behandlung keinen Effekt auf die Nikotianamin- und Phytosiderophorgehalte hatte. Die Ergebnisse dieser Arbeit zeigen, dass N Düngung die Fe und Zn Anreicherung von Weizenkörnern verbessern kann und zwar besonders dann, wenn die unterschiedlichen Effekte der N Düngerform berücksichtigt werden, während die Zitratapplikation zu keiner erhöhten Fe und Zn Anreicherung in den Körnern geführt hat.

Ever since the energy crisis in 1970¿s, hydrogen (H) has been regardedas one of the carbon-free secondary energy sources. In this context, hydrogenstorage materials have been considered as possible candidates ofclean energy storage media (see e.g. website of Department of Energy inUS [DOE]). Hydrogen is the smallest and the lightest element and thuscan be easily absorbed in interstitial sites of metal lattice. A pioneeringwork in this field is known by Sieverts [Siev29]. In some of metal alloyswith tailored composition, considerable amount of hydrogen (several wt%)can be reversibly stored through metal/metal hydride (MH) phase transition,just by controlling pressure or temperature [Vught70]. Practically,some of them (LaNi5, TiFe) are really easy to handle and have alreadybeen utilized for technical applications like in fuel cell system [Iwas03] orin MH refrigerator [Uchi04] after intensive studies and developments inthis field. Owing to its extraordinary high volume density and high stability,such metal hydrides still hold advantage to other storage methodslike liquid hydrogen or high-pressure H2 gas tanks. Currently, further researchand development is on the way focusing on improvement of gravimetrichydrogen density and reaction kinetics [Orimo07, Dornh07].

As a result of demographic pressure, governmental policies and improved market access, agricultural practices were intensified in the tropical mountainous areas of Southeast Asia. Side effects are water erosion and landslides on steep slopes creating tremendous sediment fluxes in these mountainous headwater systems. The construction of reservoirs allowed storing rainfall and runoff water in order to feed irrigation systems, supporting a second rice crop outside of the rainy season. In the rainy season these systems act as a sediment conveyor transporting and re-allocating nutrients in the lowland. The goal of this thesis which was to: (i) trace and quantify sediment associated organic carbon and total nitrogen fluxes in irrigation water, (ii) assess whether sediment deposition enhances soil spatial variation and crop performance along toposequences of paddy rice terraces and (iii) to understand the influence of flooding events on farmers¿ perception in relation to agricultural practices and adaptation of mitigation strategies.The study showed the importance of irrigation management on nutrient reallocation in the lowland and estimated that the reservoir accounted for more ten 93% of these C and N loads. Paddies close to the irrigation channel received less nutrient rich sediment, which resulted in a decrease of SOC and Total N content and an increase in sand fraction. Grain yield measurements followed the same pattern as the soil spatial variation found in the rice fields. However, sediment delivery via flooding (or direct runoff, in the case of rainfed paddies) strongly decreased soil fertility and crop productivity as these were nutrient poor ¿ sandy sediments. Individual farmers¿ willingness to adopt mitigation strategies was influenced by the economic impact of flooding at household level, external factors (e.g. climatic factors, water management failures) and a lack of understanding of the linkage between upland and lowland agricultural practices. Successful implementation of soil conservation techniques therefore will depend highly on local policy makers as they need to invest in raising farmers¿ awareness regarding upland-lowland linkages and providing appropriate incentives.As the understanding of nutrient redistribution processes is not straight forward and has a high spatio-temporal character, this work showed that the combination of stable isotope techniques, field measurements and mixed models helped in understanding the linkage between upland erosion and lowland sedimentation and moreover on crop productivity at toposequence level. The assessment of nutrient enrichment and depletion regions within the lowland can be used in designing site-specific fertilizer and water management practices. Furthermore, the identification of the processes behind nutrient redistribution allows modelers and policy makers to better assess the impact of land use change on ecosystems.