Die Modulation von Distorsionsprodukt-Otoemissionen (DPOAE) durch Töne tiefer Frequenz ist ein Methode, mit der die Auswirkung von Verlagerungen der kochleären Trennwand auf die Funktion des kochleären Verstärkers untersucht werden kann. Damit bietet sie einen neuen objektiven Ansatz zur Diagnostik unterschiedlicher kochleärer Hörstörungen sowie zur Untersuchung physiologischer Mechanismen der Kochlea. Durch einen tieffrequenten Ton (f = 32,8 Hz) werden die DPOAE in Abhängigkeit von dessen Phase periodisch verändert. Die Ausprägung der Modulation hängt von den Parametern des Tieftons und der Primärtöne (mit den Frequenzen f1 und f2) ab. Bei zwölf normalhörenden Probanden wird der Einfluß des Tieftonpegels, der Primärtonpegel und der Primärtonfrequenzen auf die Modulation der DPOAE mit der Frequenz 2f1-f2 untersucht. Die Ergebnisse dieser Methode werden mit denen der subjektiven Phasenaudiometrie bei diesen Probanden verglichen. Mit den Primärtonfrequenzen f1 = 2,5 und f2 = 3 kHz steigt die mittlere Modulationstiefe der DPOAE mit zunehmendem Tieftonpegel sowie mit abnehmenden Primärtonpegeln nichtlinear. Mit hohem Tieftonpegel (L = 115 dB SPL) und geringen Primärtonpegeln (bis zu L1 = 50 und L2 = 30 dB HL) sind DPOAE-Pegelverläufe mit zwei Minima und zwei Maxima pro Tieftonperiode zu beobachten. Die Pegelminima liegen kurz nach der maximalen Druck- bzw. Sogphase des Tieftons vor dem Trommelfell, entsprechend der maximalen Auslenkung der kochleären Trennwand in Richtung Scala vestibuli bzw. Scala tympani. Sie zeigen eine mittlere Latenz von 4 ms gegenüber den Verdeckungsmaxima der subjektiven Mithörschwelle im Phasenaudiogramm, die wahrscheinlich durch die Summe der Antwortzeit der aktiven kochleären Prozesse und der Laufzeit der DPOAE-Signale retrograd aus der Kochlea zur Meßsonde im äußeren Gehörgang zustande kommt. Mit geringeren Tieftonpegeln (L = 110 dB SPL) bzw. höheren Primärtonpegeln (ab L1 = 55 und L2 = 40 dB HL) sowie höheren Primärtonfrequenzen (f1 = 4, f2 = 4,8 kHz) sind nur noch jeweils ein DPOAE-Pegelminimum und -maximum pro Tieftonperiode zu beobachten. Mit den Primärtonfrequenzen f1 = 5 und f2 = 6 kHz zeigt sich keine Modulation der DPOAE mehr. Die Ergebnisse werden unter Verwendung einer Boltzmannfunktion zweiter Ordnung als Annäherung an die mechano-elektrische Transferfunktion äußerer Haarzellen simuliert. Bei einigen Probanden werden außerdem die Modulation der DPOAE mit der Frequenz 3f1-2f2 durch den tieffrequenten Ton sowie der Einfluß spontaner otoakustischer Emissionen (SOAE) auf die Messung tieftonmodulierter DPOAE untersucht. / Low-frequency modulation of distortion product otoacoustic emissions (DPOAE) is a method which allows to investigate the effect of the displacement of the cochlear partition on the function of the active cochlear process. It offers a new objective approach to diagnose different sensory hearing disorders as well as to investigate physiological cochlear mechanisms. The DPOAE are modulated by a low-frequency tone (with the frequency f = 32,8 Hz), depending on its phase. The extent of this modulation depends on the acoustic parameters of the suppressing low-frequency tone and the stimulating primary tones (f1 and f2). In twelve normal hearing subjects the influence of the low-frequency tone level, the levels and the frequencies of the primary tones on the modulation of the DPOAE with the frequency 2f1-f2 are investigated. In these subjects, the phase-dependent masked subjective threshold is also registered. The results of both methods are compared. With the primary tone frequencies f1 = 2,5 and f2 = 3 kHz the mean value of the DPOAE modulation depth presents a nonlinear growth with increasing low-frequency tone level and decreasing primary tone levels, respectively. With high low-frequency tone level (L = 115 dB SPL) and low primary tone levels (up to L1 = 55 and L2 = 40 dB HL), the time course of the DPOAE level shows two minima and two maxima within one period of the low-frequency tone. The minimal DPOAE levels are registered shortly after the phases of maximal condensation and rarefaction of the low-frequency tone in front of the eardrum, respectively, corresponding to the largest displacement of the cochlear partition towards the scala tympani and the scala vestibuli. The time course of the DPOAE level shows a mean latency of 4 ms with regard to the masking patterns of the phase-dependent masked threshold, due to the response time of the active cochlear process and the retrograde travelling time of the DPOAE. With lower low-frequency tone levels (L1 = 110 dB SPL), higher primary tone levels (from L1 = 55, L2 = 40 dB HL), and higher primary tone frequencies (f1 = 4, f2 = 4,8 kHz), respectively, the DPOAE level presents only one maximum and one minimum per period of the low-frequency tone. With the primary frequencies f1 = 5 and f2 = 6 kHz no modulation of the DPOAE is registered. The results are simulated using a second-order Boltzmann function as an approximation of the mechano-electric transfer function of the outer hair cells. Additionally, in some subjects the low-frequency modulation of the DPOAE with the frequency 3f1-2f2 and the influence of spontaneous otoacoustic emissions (SOAE) on the registration of low-frequency modulated DPOAE are investigated.

In dieser Dissertation wird die spektrale und örtliche Verteilung der Lumineszenz von Heterostrukturen in selbstorganisierten Nanodrähten (ND) mit Hilfe von Kathodolumineszenz-Spektroskopie (KL) im Rasterelektronenmikroskop untersucht. Diese Methode wird ergänzt durch Messungen der kontinuierlichen und zeitaufgelösten Mikro-Photolumineszenz. Drei verschiedene Strukturen werden behandelt: (i) GaAs-ND bestehend aus Segmenten der Wurtzit (WZ) bzw. Zinkblende (ZB) Kristallstrukturen, (ii) auf GaN-ND überwachsene GaN-Mikrokristalle und (iii) (In,Ga)N Einschlüsse in GaN-ND. Die gemischte Kristallstruktur der GaAs-ND führt zu komplexen Emissionsspektren. Dabei wird entweder ausschließlich Lumineszenz bei Energien unterhalb der ZB Bandlücke, oder aber zusätzlich bei höheren Energien, gemessen. Diese Differenz wird durch unterschiedliche Dicken der ZB und WZ Segmente erklärt. Messungen bei Raumtemperatur zeigen, dass die Bandlücke von WZ-GaAs mindestens 55 meV größer als die von ZB-GaAs ist. Die Lumineszenz-Spektren der GaN-Mikrokristalle enthalten verschiedene Emissionslinien, die auf Stapelfehler (SF) zurückzuführen sind. SF sind ZB Quantentöpfe verschiedener Dicke in einem WZ-Kristall und es wird gezeigt, dass ihre Emissionsenergie durch die spontane Polarisation bestimmt wird. Aus einer detaillierten statistischen Analyse der Emissionsenergien der verschiedenen SF-Typen werden Emissionsenergien von 3.42, 3.35 und 3.29 eV für die intrinsischen (I1 und I2) sowie für extrinsische SF ermittelt. Aus den entsprechenden Energiedifferenzen wird -0.022C/m² als experimenteller Wert für die spontane Polarisation von GaN bestimmt. Die Bedeutung sowohl der piezoelektrischen Polarisation als auch die der Lokalisierung von Ladungsträgern wird für (In,Ga)N-Einschlüsse in GaN-ND gezeigt. Hierbei spielt nicht nur die Lokalisierung von Exzitonen, sondern auch die individueller Elektronen und Löcher an unterschiedlichen Potentialminima eine Rolle. / In this thesis, the spectral and spatial luminescence distribution of heterostructures in self-induced nanowires (NWs) is investigated by cathodoluminescence spectroscopy in a scanning electron microscope. This method is complemented by data from both continuous and time-resolved micro-photoluminescence measurements. Three different structures are considered: (i) GaAs NWs containing segments of the wurtzite (WZ) and zincblende (ZB) polytypes, (ii) GaN microcrystals overgrown on GaN NWs, and (iii) (In,Ga)N insertions embedded in GaN NWs. The polytypism of GaAs NWs results in complex emission spectra. The observation of luminescence either exclusively at energies below the ZB band gap or also at higher energies is explained by differences in the distribution of ZB and WZ segment thicknesses. Measurements at room temperature suggest that the band gap of WZ GaAs is at least 55 meV larger than that of the ZB phase. The luminescence spectra of the GaN microcrystals contain distinct emission lines associated with stacking faults (SFs). SFs essentially constitute ZB quantum wells of varying thickness in a WZ matrix and it is shown that their emission energy is dominated by the spontaneous polarization. Through a detailed statistical analysis of the emission energies of the different SF types, emission energies of 3.42, 3.35 and 3.29 eV are determined for the intrinsic (I1 and I2) as well as the extrinsic SFs, respectively. From the corresponding energy differences, an experimental value of -0.022C/m² is derived for the spontaneous polarization of GaN. The importance of both carrier localization and the quantum confined Stark effect induced by the piezoelectric polarization is shown for the luminescence of (In,Ga)N insertions in GaN NWs. Not only localized excitons, but also electrons and holes individually localized at different potential minima contribute to the observed emission.

Suburothelial myofibroblasts (sMF) are located underneath the urothelium in close proximity to afferent nerves and show spontaneous calcium activity in vivo and in vitro. They express purinergic receptors and calcium transients can be evoked by ATP. Therefore they are supposed to be involved in afferent signaling of the bladder fullness. Myofibroblast cultures, established from cystectomies, were challenged by exogenous ATP in presence or absence of purinergic antagonist. Fura-2 calcium imaging was used to monitor ATP (10-16 to 10-4 mol/l) induced alterations of calcium activity. Purinergic receptors (P2X1, P2X2, P2X3) were analysed by confocal immunofluorescence. We found spontaneous calcium activity in 55.18% ± 1.65 (mean ± SEM) of the sMF (N=48 experiments). ATP significantly increased calcium activity even at 10-16 mol/l. The calcium transients were partially attenuated by subtype selective antagonist (TNP-ATP, 1μM; A-317491, 1μM), and were mimicked by the P2X1, P2X3 selective agonist α,β-methylene ATP. The expression of purinergic receptor subtypes in sMF was confirmed by immunofluorescence. Our experiments demonstrate for the first time that ATP can modulate spontaneous activity and induce intracellular Ca2+ response in cultured sMF at very low concentrations, most likely involving ionotropic P2X receptors. These findings support the notion that sMF are able to register bladder fullness very sensitively, which predestines them for the modulation of the afferent bladder signaling in normal and pathological conditions.

No description available.

In this thesis, quantum cluster methods are used to calculate electronic properties of correlated-electron systems. A special focus lies in the determination of the ground state properties of a 3/4 filled triangular lattice within the one-band Hubbard model. At this filling, the electronic density of states exhibits a so-called van Hove singularity and the Fermi surface becomes perfectly nested, causing an instability towards a variety of spin-density-wave (SDW) and superconducting states. While chiral d+id-wave superconductivity has been proposed as the ground state in the weak coupling limit, the situation towards strong interactions is unclear. Additionally, quantum cluster methods are used here to investigate the interplay of Coulomb interactions and symmetry-breaking mechanisms within the nematic phase of iron-pnictide superconductors. The transition from a tetragonal to an orthorhombic phase is accompanied by a significant change in electronic properties, while long-range magnetic order is not established yet. The driving force of this transition may not only be phonons but also magnetic or orbital fluctuations. The signatures of these scenarios are studied with quantum cluster methods to identify the most important effects. Here, cluster perturbation theory (CPT) and its variational extention, the variational cluster approach (VCA) are used to treat the respective systems on a level beyond mean-field theory. Short-range correlations are incorporated numerically exactly by exact diagonalization (ED). In the VCA, long-range interactions are included by variational optimization of a fictitious symmetry-breaking field based on a self-energy functional approach. Due to limitations of ED, cluster sizes are limited to a small number of degrees of freedom. For the 3/4 filled triangular lattice, the VCA is performed for different cluster symmetries. A strong symmetry dependence and finite-size effects make a comparison of the results from different clusters difficult. The ground state in the weak-coupling limit is superconducting with chiral d+id-wave symmetry, in accordance to previous renormalization group approaches. In the regime of strong interactions SDW states are preferred over superconductivity and a collinaer SDW state with nonuniform spin moments on a quadrupled unit cell has the lowest grand potential. At strong coupling, inclusion of short-range quantum fluctuations turns out to favor this collinear state over the chiral phase predicted by mean-field theory. At intermediate interactions, no robust conclusion can be drawn from the results. Symmetry-breaking mechanisms within the nematic phase of the iron-pnictides are studied using a three-band model for the iron planes on a 4-site cluster. CPT allows a local breaking of the symmetry within the cluster without imposing long-range magnetic order. This is a crucial step beyond mean-field approaches to the magnetically ordered state, where such a nematic phase cannot easily be investigated. Three mechanisms are included to break the fourfold lattice symmetry down to a twofold symmetry. The effects of anisotropic magnetic couplings are compared to an orbital ordering field and anisotropic hoppings. All three mechanisms lead to similar features in the spectral density. Since the anisotropy of the hopping parameters has to be very large to obtain similar results as observed in ARPES, a phonon-driven transition is unlikely.

In this thesis, quantum cluster methods are used to calculate electronic properties of correlated-electron systems. A special focus lies in the determination of the ground state properties of a 3/4 filled triangular lattice within the one-band Hubbard model. At this filling, the electronic density of states exhibits a so-called van Hove singularity and the Fermi surface becomes perfectly nested, causing an instability towards a variety of spin-density-wave (SDW) and superconducting states. While chiral d+id-wave superconductivity has been proposed as the ground state in the weak coupling limit, the situation towards strong interactions is unclear. Additionally, quantum cluster methods are used here to investigate the interplay of Coulomb interactions and symmetry-breaking mechanisms within the nematic phase of iron-pnictide superconductors. The transition from a tetragonal to an orthorhombic phase is accompanied by a significant change in electronic properties, while long-range magnetic order is not established yet. The driving force of this transition may not only be phonons but also magnetic or orbital fluctuations. The signatures of these scenarios are studied with quantum cluster methods to identify the most important effects. Here, cluster perturbation theory (CPT) and its variational extention, the variational cluster approach (VCA) are used to treat the respective systems on a level beyond mean-field theory. Short-range correlations are incorporated numerically exactly by exact diagonalization (ED). In the VCA, long-range interactions are included by variational optimization of a fictitious symmetry-breaking field based on a self-energy functional approach. Due to limitations of ED, cluster sizes are limited to a small number of degrees of freedom. For the 3/4 filled triangular lattice, the VCA is performed for different cluster symmetries. A strong symmetry dependence and finite-size effects make a comparison of the results from different clusters difficult. The ground state in the weak-coupling limit is superconducting with chiral d+id-wave symmetry, in accordance to previous renormalization group approaches. In the regime of strong interactions SDW states are preferred over superconductivity and a collinaer SDW state with nonuniform spin moments on a quadrupled unit cell has the lowest grand potential. At strong coupling, inclusion of short-range quantum fluctuations turns out to favor this collinear state over the chiral phase predicted by mean-field theory. At intermediate interactions, no robust conclusion can be drawn from the results. Symmetry-breaking mechanisms within the nematic phase of the iron-pnictides are studied using a three-band model for the iron planes on a 4-site cluster. CPT allows a local breaking of the symmetry within the cluster without imposing long-range magnetic order. This is a crucial step beyond mean-field approaches to the magnetically ordered state, where such a nematic phase cannot easily be investigated. Three mechanisms are included to break the fourfold lattice symmetry down to a twofold symmetry. The effects of anisotropic magnetic couplings are compared to an orbital ordering field and anisotropic hoppings. All three mechanisms lead to similar features in the spectral density. Since the anisotropy of the hopping parameters has to be very large to obtain similar results as observed in ARPES, a phonon-driven transition is unlikely.

Suburothelial myofibroblasts (sMF) are located underneath the urothelium in close proximity to afferent nerves and show spontaneous calcium activity in vivo and in vitro. They express purinergic receptors and calcium transients can be evoked by ATP. Therefore they are supposed to be involved in afferent signaling of the bladder fullness. Myofibroblast cultures, established from cystectomies, were challenged by exogenous ATP in presence or absence of purinergic antagonist. Fura-2 calcium imaging was used to monitor ATP (10-16 to 10-4 mol/l) induced alterations of calcium activity. Purinergic receptors (P2X1, P2X2, P2X3) were analysed by confocal immunofluorescence. We found spontaneous calcium activity in 55.18% ± 1.65 (mean ± SEM) of the sMF (N=48 experiments). ATP significantly increased calcium activity even at 10-16 mol/l. The calcium transients were partially attenuated by subtype selective antagonist (TNP-ATP, 1μM; A-317491, 1μM), and were mimicked by the P2X1, P2X3 selective agonist α,β-methylene ATP. The expression of purinergic receptor subtypes in sMF was confirmed by immunofluorescence. Our experiments demonstrate for the first time that ATP can modulate spontaneous activity and induce intracellular Ca2+ response in cultured sMF at very low concentrations, most likely involving ionotropic P2X receptors. These findings support the notion that sMF are able to register bladder fullness very sensitively, which predestines them for the modulation of the afferent bladder signaling in normal and pathological conditions.:1. Introduction............................................................................ 1 1.1. Anatomy and histology of the human urinary bladder..................... 1 1.1.1. Anatomy of the human urinary bladder..................................... 1 1.1.2. Structure of the human urinary bladder wall............................... 2 1.2. Normal bladder function and bladder dysfunction.......................... 3 1.2.1 Normal bladder function......................................................... 3 1.2.2 Sensory aspect.................................................................... 4 1.2.3 Overactivity or hypersensitivity of bladder.................................. 5 1.3 The role of functional cell types and interaction in urinary bladder... 6 1.3.1 The role of urothelium.......................................................... 7 1.3.2Theroleofsuburotheliamyofibroblast...................................... 7 1.3.3Theroleofdetrusorsmoothmusclecells.................................. 9 1.3.4 Possible interactions in urinary bladder cell types........................ 10 1.4 ATP function and Purinergic signalling in bladder........................... 11 1.5 Spontaneous activity of bladder................................................... 13 2. Objective.................................................................................. 15 3. Material and methods............................................................... 16 3.1. Ethics Statement........................................................................ 16 3.2. Cell preparation.......................................................................... 16 3.3. Solutions and chemicals............................................................. 19 3.4. Intracellular calcium measurements............................................. 20 2.4.1. Preparing cells for Calcium Imaging.......................................... 20 2.4.2. Preparing workspace of calcium imaging................................... 20 2.4.3. Calcium imaging recording...................................................... 22 3.5 Data analysis with automated Fluorescence analysis..................... 22 3.6 Confocal Immunofluorescence.................................................... 25 3.7 Statistics................................................................................. 26 4. Results.................................................................................. 27 4.1 Spontaneous calcium activity of sMF........................................... 27 4.2 ATP effects on calcium response in sMF...................................... 27 4.3 Analysis of purinergic receptors involved.................................... 30 3.3.1 Agonist stimulation.............................................................. 30 3.3.2 Signal inhibition by specific antagonists................................... 31 4.4 Confocal immunofluorescence of purinergic receptors.................. 32 5. Discussion............................................................................. 34 5.1 Myofibroblast identification....................................................... 34 5.2 Spontaneous activity in the bladder............................................ 36 5.3 ATP modulated calcium activity in sMF....................................... 37 5.4 purinergic signalling in sMF........................................................ 39 6. Summary................................................................................ 42 7. References.............................................................................. 45 Declaration............................................................................. 50 Acknowledgements................................................................. 51

In dieser Arbeit untersuchen wir kollektive Strahlungseffekte in Nanofaser-gekoppelten atomaren Ensembles, die sich über Tausende von optischen Wellenlängen erstrecken. Wir koppeln bis zu 1000 Atome optisch an die geführten Moden einer optischen Nanofaser, die langreichweitige Dipol-Dipol Wechselwirkungen zwischen den Atomen vermittelt. Wir realisieren eine unidirektionale Kopplung und damit ein kaskadiertes Quantensystem, in dem die Dynamik jedes Atoms ausschließlich durch die Dynamik der vorgelagerten Atome bestimmt wird. Wir regen die Atome mit nanofasergeführten optischen Pulsen kohärent an, was uns ermöglicht, den gesamten Parameterbereich von schwacher Anregung bis hin zur voll-ständigen Inversion zu erforschen. Wir stellen fest, dass die kohärente Vorwärtsstreuung, die für die Superradianz im Regime der schwachen Anregung verantwortlich ist, auch nahe voller Inversion eine wichtige Rolle für die Dynamik spielt. Wir beobachten superradiante Puls-Dynamik, die in unserem System trotz des makroskopischen Abstands zwischen den Atomen und einer asymmetrischen Kopplung auftritt. Wir stellen fest, dass die emittierte Spitzenleistung noch schneller mit der Anzahl der Atome skaliert als im Fall der idealen Dicke Superradianz, was auf eine kollektiv erhöhte Sammeleffizienz der nanofasergeführten Mode zurückzuführen ist. Die Analyse der Kohärenz-Eigenschaften des superradianten Pulses erlaubt es uns, zwei Regime der Puls-Dynamik zu identifizieren. Wir entwickeln ein kaskadiertes Wechselwirkungsmodell und zeigen, dass es die kollektive Dynamik unseres Systems über den gesamten in dieser Arbeit untersuchten Parameterbereich akkurat beschreibt. Schließlich untersuchen wir die getriebene Dynamik eines Nanofaser-gekoppelten Ensembles von Drei-Niveau-Atomen. Wir treiben Zwei-Photonen-Rabi-Oszillationen zwischen den beiden Grundzuständen eines $\Lambda$-Systems und beobachten die damit verbundene oszillatorische Raman-Verstärkung und -Absorption. / In this thesis, we study collective radiative effects in nanofiber-coupled atomic ensembles that extend over thousands of optical wavelengths. We optically couple up to 1000 atoms to the guided modes of an optical nanofiber, which mediates long-range dipole-dipole interactions between the atoms. We engineer the coupling to be unidirectional, realizing a cascaded quantum system in which the dynamics of each atom is solely determined by the dynamics of upstream atoms. We coherently excite the atoms using nanofiber-guided optical pulses, allowing us to explore the entire parameter regime from weak excitation to full inversion. We find that coherent forward scattering, which is responsible for superradiance in the weak excitation regime, plays an important role for the dynamics even close to full inversion. We observe superradiant burst dynamics, which occurs in our system despite the macroscopic separation between the atoms and an asymmetric coupling. We find that the peak-emitted power scales even faster with the number of atoms than in the case of ideal Dicke superradiance due to a collectively enhanced channeling efficiency into the nanofiber-guided mode. By analyzing the coherence properties of the superradiant burst, we directly identify two regimes of burst dynamics. In the second regime, there is no initial coherence, and the superradiant burst is seeded by vacuum fluctuations. We introduce a cascaded interaction model and find that it accurately describes the collective dynamics of our system over the entire parameter regime explored in this thesis. Finally, we study the driven dynamics of a nanofiber-coupled ensemble of three-level atoms. We drive two-photon Rabi oscillations between the two ground states of a $\Lambda$ system and observe the associated oscillatory Raman gain and absorption.

Die verlässliche Erzeugung einzelner Photonen mit wohldefinierten Eigenschaften in allen Freiheitsgraden ist entscheidend für die Entwicklung photonischer Quantentechnologien. Derzeit basieren die wichtigsten Einzelphotonenquellen auf dem Prozess der spontanen parameterischen Fluoreszenz (SPF), bei dem ein Pumpphoton in einem nichtlinearen Medium spontan in ein Paar aus Signal und Idlerphotonen zerfällt. Resonator-überhöhte SPF, also das Plazieren des nichtlinearen Mediums in einem optischen Resonator, ist ein weit verbreitetes Verfahren, um Einzelphotonenquellen mit erhöhter Helligkeit und angepassten spektralen Eigenschaften zu konstruieren. Das Anpassen der spektralen Eigenschaften durch gezielte Auswahl der Resonatoreigenschaften ist besonders für hybride Quantentechnologienvon Bedeutung, welche darauf abzielen, unterschiedliche Quntensysteme so zu kombinieren, dass sich deren Vorteile ergänzen. Diese Arbeit stellt eine umfassende theoretische und experimentelle Analyse der dreifach resonanten SPF vor. Das aus der Literatur bekannte theoretische Modell wird diesbezüglich verbessert, dass der Einfluss sämtlicher Eigenschaften des Resonators auf die wichtigen experimentellen Größen (z.B. die Erzeugungsrate) gezielt ausgewertet werden kann. Dieses verbesserte und hoch genaue Modell stellt eine wichtige Grundlage für die Entwicklung und Optimierung neuartiger Photonenpaarquellen dar. Im experimentellen Teil dieser Arbeit wird der Aufbau und die Charakterisierung einer dreifach resonanten Photonenpaarquellen präsentiert. Die neu entwickelte digitale Regelelektronik sowie ein hochstabiler, schmalbandiger Monochromator welcher auf monolitischen, polarisationsunabhängigen Fabry-Pérot Resonatoren basiert, werden vorgestellt. Indem diese temperaturstabilisierten Resonatoren als Spetrumanalysator verwendet werden, wird zum ersten Mal die Frequenzkammstruktur des Spektrums der erzeugten Signal- und Idlerphotonen nachgewiesen. Des Weiteren wird der Einfluss der Pumpresonanz auf die Korrelationsfunktion und die Zweiphotoneninterferenz von Signal- und Idlerphotonen simuliert und vermessen. Abschließend werden Experimente aus dem Bereich der hybriden Quantennetzwerke präsentiert, in welchen Quantenfrequenzkonversion verwendet wird um die erzeugten Signalphotonen in das Telekommunikationsband zu transferieren. Dabei wird nachgewiesen, dass das temporale Wellenpaket durch die Konversion nicht beeinflusst wird und aufgezeigt, wie Quantennetzwerke von kommerziellen Telekommunikationstechnologien profitieren können. / The consistent generation of single photons with well-defined properties in all degrees of freedom is crucial for the development of photonic quantum technologies. Today, the most prominent sources of single photons are based on the process of spontaneous parametric down-conversion (SPDC) where a pump photon spontaneously decays into a pair of signal and idler photons inside a nonlinear medium. Cavity-enhanced SPDC, i.e., placing the nonlinear medium inside an optical cavity, is widely used to build photon-pair sources with increased brightness and tailored spectral properties. This spectral tailoring by selective adjustment of the cavity parameters is of particular importance for hybrid quantum technologies which seek to combine dissimilar quantum systems in a way that their advantages complement each other. This thesis provides a comprehensive theoretical and experimental analysis of triply-resonant cavity-enhanced SPDC. We improve the theoretical model found in the literature such that the influence of all resonator properties on the important experimental parameters (e.g., the generation rate) can be analyzed in detail. This convenient and highly accurate model of cavity-enhanced SPDC represents an important basis for the design and optimization of novel photonpair sources. The experimental part of this thesis presents the setup and characterization of a triply-resonant photon-pair source. We describe the digital control system used to operate this source over days without manual intervention, and we present a highly stable, narrow-linewidth monochromator based on cascaded, polarization-independent monolithic Fabry-Pérot cavities. Utilizing these temperature-stabilized cavities as a spectrum analyzer, we verify, for the first time, the frequency comb spectral structure of photons generated by cavity-enhanced SPDC. We further simulate and measure the impact of the pump resonance on the temporal wave-packets and the two-photon interference of signal and idler photons. Finally, we present a series of experiments in the context of hybrid quantum networks where we employ quantum frequency conversion (QFC) to transfer the generated signal photons into the telecommunication band. We verify the preservation of the temporal wave-packet upon QFC and highlight how quantum networks can benefit from advanced commercial telecommunication technologies.

In der hier vorliegenden Studie wurde ein bisher noch nicht beachteter Teil der Sportwissenschaften untersucht. Nach einer umfassenden Literaturrecherche und qualitativen Interviews wurden im Zeitraum von 2005 bis 2006 von über 500 Kampfstilschülern - und Trainern Aggressionswerte sowie sportpädagogisch und -soziologisch relevante Fakten erhoben. Hierbei wurden bewusst solche Personen befragt, die Stile mit überdurchschnittlich hartem Trefferkontakt trainieren. Neben Muay Thai, Freefight und Eskrima unter anderem Krav Maga Maar, Kyushinkai Karate und Grappling. Neben der Schaffung eines umfassenden Grundlagenmaterials zu Themen wie Herkunft, Alter, Bildung, und persönlichen Interessen werden Trainingsgewohnheiten ausgewertet und Beziehungen zu folgenden Faktoren hergestellt: Spontane Aggression, Reaktive Aggression, Summenaggression, Aggressionshemmung, Erregbarkeit und Offenheit. Zur Erfassung der genannten Faktoren wurde der FAF-Test verwendet. Neben einer überdurchschnittlichen Bildung, und im allgemeinen sehr geringen Aggressionswerten konnten auch Tendenzen festgestellt werden, nachdem einige Schüler ihr erlernten Techniken für gezielte Aggressionen außerhalb des Trainings nutzen. Weitere unerwartete Ergebnisse fanden sich unter anderem in den unterschiedlichen Einschätzungen von Trainern und ihren Schülern im Bezug auf deren pädagogischen Einfluss jenseits des Techniktrainings. / The aim of this study is to investigate a field of physical education which has been ignored up to now. After a literature review and a qualitative interview analyses more than 500 martial arts coaches and students have been asked from 2005 to 2006 to collect aggressiveness values and different sports pedagogy and -sociologic relevant data .The study was targeted at "hard -style" martial arts such as Muay Thai, Freefight, Escrima, Krav Maga Maar, Kyushinkai Karate and Grappling. One of the aims was to collect substructal data such as social background, age, education and hobbies. The training data was evaluated and related to the following factors using the FAF Test: Spontaneous Aggression, Reactive Aggression, Aggressionsum, Aggression Escapement, Impulsiveness and Openness. Beside an above-average education and in general low aggressiveness factors the results of the study were a tendency towards the utilisation of martial arts techniques for violent behaviour outside the dojo. Further results include different ratings in the effectiveness of the pedagogical impact of teacher on their students.