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Investigation of magnetic anomalies in archaeological prospection
Get PDFMagnetometer prospecting refers to mapping the magnetic field and is an essential method in archaeological prospecting and archaeogeophysics for investigating large surface areas. Permanent and induced magnetic fields of potential features, as well as the Earth’s magnetic field, are registered, but the identification of the archaeological features relies fundamentally on the magnetisation contrast to the surroundings. The devices used are categorised as scalar and vector magnetometers, which provide different elements of the superimposed fields, resulting after data processing in different visual outputs. A new approach is presented to merge vector gradiometer with high-pass filtered total field magnetometer data to obtain visually uniform magnetograms for better interpretation. The registered anomaly of a feature depends on several source-specific parameters, among them the direction of its magnetisation. Inspired by the fieldwork at Artanish, synthetic magnetograms were generated to investigate the effect of the total magnetisation variation on a spherical object’s anomaly pattern. The results are discussed in terms of the impact of the remanence and their significance for the survey interpretation. The anomaly pattern also depends on the direction of the Earth’s magnetic field. From synthetic magnetograms and profiles, it was determined that the effect of the declination is avoidable for prospecting. The effect of the inclination is not compensable as anomaly patterns and peak ratios vary significantly with the inclination of the Earth’s magnetic field. For the case of an inclination of 15°, modelling results are compared to data collected at an isocline of 15° and the effect of the inclination discussed for spherical and linear features. Three case studies show the applicability of magnetometer prospecting under different conditions and for different research questions. Prospecting at the Sumerian site of Suruppak, the modern Fara, brought new insights into the excavation of 1902/1903 and answered opened questions about the existence of a city wall and harbour, canal routing and settlement structure of the ancient site. The case study of Yeha and Melazo portrays how complex magnetograms appear at sites still inhabited today. Archaeological features can only be reliably identified if geological and surface anomalies of recent buildings or agricultural use are recognised. The original idea of magnetometer prospecting in Gumbati was to re-locate the mid-1990s excavation or to find related features to the Achaemenid complex discovered back then. The resulting magnetograms show prominent rectangular features that were targeted in a subsequent excavation, but the source of the magnetic anomalies was not uncovered. Chemical analyses and susceptibility measurements indicate that fertiliser residues could be the reasons for these anomalies
Expanding the scope of adeno-associated-virus vectors
Get PDFGene therapy of inherited retinal dystrophies (IRDs) using vectors based on adeno-associated viruses (AAVs) has been widely explored to intervene in the progression of retinal degeneration. However, AAVs are further investigated outside the field of gene supplementation approaches allowing for unconventional platforms of use.
Here, we introduce novel AAV9-based capsid variants displaying small peptide insertions attempting to alter the natural tropism for effective transduction of retinal cells after less invasive intravitreal (IVT) administration. Previously heparan-sulfate proteoglycan (HSPG) binding has been shown to significantly contribute to retinal cell tropism. Therefore, we introduced an artificial HSPG-binding site with peptide insertions to investigate how this affects penetration of retinal cell layers after IVT administration. A total of ten different AAV9-based variants were characterized on technical aspects as well as in vitro, ex vivo and in vivo tropism and transduction properties in mouse retina. AAV9.NNR and AAV9.GLR outperformed AAV9 wildtype as well as previous AAV9 variants lacking a HSPG motif in vitro and showed strong eGFP expression in vivo. Moreover, AAV9.NNR, AAV9.GLR and AAV9.RAAK mediated efficient transduction of the non-pigmented epithelium (NPCE) of the ciliary body in C57BL/6 mice.
Further, we explore the potential of a novel vaccination platform which uses AAV capsids as scaffolds for large immunogenic epitopes to induce strong and specific immune responses using COVID-19 as a model disease to evaluate this approach. To this end, we introduced large immunogenic peptide insertions of approximately 200 amino acids on the surface exposed loop IV of AAV2 and AAV9. Empty, virus-like particles (VLPs) without vector genome were produced and administered subcutaneously in adult rabbits showing potent IgG and IgM responses specific to the presented antigen. Additionally, vector incubation with blood plasma of mRNA-vaccinated human donors resulted in antigen-specific neutralization effects in vitro.
In summary, we introduce novel AAV9-based capsid variants with artificial HSPG-binding motifs that show superior transduction efficiency for retinal cells and additional tropism for ciliary body cells. Furthermore, we present a novel platform that expands the toolbox of AAVs as immunogenic scaffolds for the development of next-generation vaccines in the context of diseases where traditional vaccination approaches have so far not succeeded
Ly6D+ Siglec-H+ precursor cells contribute to conventional dendritic cells via a Siglec-H+ Zbtb46+ Ly6D+ intermediary stage
Get PDFDendritic cells (DC) are antigen-presenting cells that form an indispensable part of the immune system. While conventional/classical dendritic cells (cDC) are largely involved in orchestrating T cell responses to extracellular pathogens and in anti-tumor immune responses, plasmacytoid dendritic cells (pDC) are the main driver of anti-viral defense through production of large amounts of type I interferons in response to viral infection.
The origin and differentiation of these functionally distinct pDC and cDC has been studied extensively in the past decades, but the respective DC ontogeny is still subject to debate.
In this study the CD11c+ Siglec-H+ CCR9low DC precursor fraction in murine bone marrow (BM) was studied in detail to unravel the heterogeneity of cells within this compartment and their commitment to cDC and/or alternative pDC fate. In steady state conditions, CD11c+ Siglec-H+ Ly6D+ Zbtb46- CCR9low B220high cells had almost exclusive pDC potential, while CCR9low B220low cells gave rise to pDC as well as cDC in vitro and after adoptive transfer in vivo. I further demonstrated that stimulating these cells with TLR9 agonists and type I interferons increased pDC output while limiting cDC output in vitro by driving pDC maturation and at the same time impeding pre-cDC proliferation and terminal differentiation.
Data from single-cell RNA-sequencing of DC related cell populations and multiparameter spectral flow cytometry of steady-state BM and splenic cells of Zbtb46wt/ki mice were analyzed using powerful bioinformatic tools, leading to the discovery of a cDC-committed CD11c+ Siglec-H+ Zbtb46+ Ly6D+ precursor cell population that bridges the gap between CD11c+ Siglec-H+ Ly6D+ lymphoid-derived pDC-biased precursors and pre-cDCs.
In vitro and in vivo differentiation assays further showed that cells with this phenotype mark a transitional state between advanced CD11c+ Siglec-H+ CCR9low lymphoid precursors and mature cDCs. The contribution of lymphoid precursors to cDCs may be relevant when cDCs are depleted and their regeneration from myeloid progenitor cells is impaired, such as during severe infections
The effects of triple blockade of the mineralocorticoid receptor, the renin-angiotensin system, and sodium glucose transporter 2 on kidney lifespan in mice with Alport nephropathy
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The emergence of continuum gravitational physics from group field theory models of quantum gravity
Get PDFQG Theorien streben danach, die grundlegenden Theorien von GR und QFT in der theoretischen Physik mit einer kohärenten Weltbeschreibung in Verbindung zu bringen. Dieses dynamische Forschungsgebiet ist eine Kreuzung verschiedener physikalischer Disziplinen, die von der phänomenologischen bis hin zur abstrakten mathematischen Physik reichen. In dieser Arbeit widmen wir uns der Entstehung der Kontinuumsgravitationsphysik aus dem QG-Hintergrund unabhängigen Theorie der GFT. Insbesondere untersuchen wir seine Beziehung zu anderen QG-Modellen wie SF im Rahmen der Modellbildung für 4d Lorentzsche Quantengeometrien, die Berührung zwischen Quantenverschränkung (als Preview von Entstehung) und Quantengeometrie durch die Ausnutzung von Spin-Netzwerk-Zuständen, die Quantengeometrien charakterisieren, und schließlich die kulminierende Phase der Extraktion einer effektiven Beschreibung der kosmologischen Fassung der Theorie in der Sprache einer Feldtheorie, die sich auf einem gekrümmten Hintergrund ausbreitet. Diese Forschungsschwerpunkte dieser Dissertation lassen sich wie folgt präzise zusammenfassen: Zunächst stellen wir die Konstruktion eines neuen SF-Modells für 4d Lorentz’sche Quantengravitation vor, das auf der Beschreibung einer vereinfachten Quantengeometrie beruht, die sich auf edge vector-Variablen stützt. Auf der repräsentationstheoretischen Seite werden Quantenzustände der Geometrie aus irreduziblen Darstellungen der Translationsgruppe auf dem Minkowski-Raum oder Funktionen auf der Translationsgruppe selbst gebildet. Wir zeigen auch, wie das neue Modell mit dem Lorentzschen Barrett-Crane BC-Spinschaum-Modell für einen Sektor seiner Quantenkonfigurationen zusammenhängt. Das neue Modell besitzt offensichtlich alle relevanten Freiheitsgrade, um die vereinfachte Geometrie auf Quantenebene zu beschreiben, und stellt somit einen vielversprechenden Vorschlag für die Lorentzsche Quantengravitation dar. Es kann daher auch als Ergänzung (oder notwendiger Bezugspunkt) für bekannte Spin-Schaum-Modelle angesehen werden, die auf einer eingeschränkten BF-Quantisierung und einer Formulierung der Quantengeometrie in Form von Kantenvektoren basieren. Anschließend untersuchen wir die Verschränkung/geometrische Charakterisierung von generischen überlagerten Quantengeometrien. Der Vorschlag, dass die Raumzeit und ihre geometrischen Eigenschaften aus rein nicht-geometrischen Freiheitsgraden entstehen, die dann wiederum eng mit Verschränkungsmaßen verknüpft sind, hat im Bereich der Quanteninformation QIT viel Aufmerksamkeit erregt. Wir stellen eine unkomplizierte Umsetzung dieser Techniken in QG-Modellen vor, bei denen wir uns auf eine bestimmte Gruppe von QG-Zuständen konzentrieren. Konkret zeigen wir, wie die Untersuchung der Verschränkungseigenschaften einer Überlagerung von QG-Zuständen, genauer gesagt von Spin-Netzwerk-Graph-Zuständen mit unterschiedlichen kombinatorischen Strukturen, auf natürliche Weise zu einer Verallgemeinerung der üblichen von-Neumann-Entropie führt, die für Spin-Netzwerk-Zustände in LQG-Berechnungen erhalten wird. Dies wird in der Tat erreicht, wenn wir verschiedene entropische Begriffe und Maße aus der Quanteninformationstheorie entlehnen, wobei der untersuchte Fall der Überlagerung von Zuständen, die von-Neumann-Entropie verschränkter Regionen bereits auf der kinematischen Ebene der Theorie zur so genannten Interaktionsentropie in QIT führt. Darüber hinaus wird ein Vergleich zwischen dem zweiten Quantisierungsformalismus dieses Schemas, der auf der Überlagerung von Zuständen beruht, und dem der LQG-Ergebnisse vorgestellt.
Schließlich besteht die verfügbare Technologie zur Erzeugung der Dynamik in der Verwendung des relationalen Rahmens, wenn kein Begriff des metrischen Hintergrunds oder alternativ dazu die Diffeomorphismusinvarianz in der Theorie vorhanden ist. Ein GFTModell, in dem dies umgesetzt wurde, ist verfügbar, und vor allem ist es gelungen, Kontinuumsphysik in einem kosmologischen Kontext zu extrahieren, der auf GFT-Kondensaten beruht, genauer gesagt in einem homogenen FLRW-Universum mit eingeschlossenen Störungen.
Ausgehend von diesen Ergebnissen leiten wir die explizite Lösung der effektiven Dynamik von GFT-Kondensaten her, die auch skalare Störungen berücksichtigt. Dieser erste Schritt ermöglichte es uns, den Materiegehalt weiter zu untersuchen und seine Dynamik in Form einer Feldtheorie auf einem gekrümmten Hintergrund zu formulieren. Dies wiederum führte zu zusätzlichen emergenten Eigenschaften, die die Feldtheorie im Vergleich zur klassischen Theorie besitzt, was sich auch auf der Ebene der Störung widerspiegelt. Im letzteren Fall haben wir eine modifizierte Dispersionsrelation für das gestörte Skalarfeld erhalten.Quantum Gravity (QG) theories pursue the goal of reconciling the pillar theories of General Relativity (GR) and Quantum Field Theory (QFT) in theoretical physics and a coherent description of the physical world surrounding us. This prosperous field of research is a crossroad of various disciplines in physics, ranging from the phenomenological to the most abstract mathematical ones. In this thesis, we devote our focus to the emergence of continuum gravitational physics from the QG background independent approach of Group Field Theory (GFT). In particular, we explore its relation to other QG models such as Spin Foam (SF) in the context of model-building of 4d Lorentzian quantum geometries, the interface between quantum entanglement (considered as the preview of emergence) and quantum geometry through the exploitation of spin network states characterizing quantum geometries, and finally the culminating stage of extracting an effective description of the cosmological version of the theory in the language of a field theory propagating on a curved background. More precisely, the three research focal points of this thesis are summarized as follows: First, we present the construction of a new SF model for 4d Lorentzian quantum gravity based on the description of quantum simplicial geometry relying on edge vector variables. On the representation theoretic side, quantum states of geometry are built from irreducible representations of the translation group on Minkowski space or functions on the translation group itself. We also show how the new model connects to the Lorentzian Barrett-Crane Barrett-Crane (BC) spin foam model, for a sector of its quantum configurations. The new model manifestly possesses all the relevant degrees of freedom to describe simplicial geometry at the quantum level and thus constitutes a promising proposal for Lorentzian quantum gravity. Hence, it may be seen also as a completion (or a necessary reference point) for known spin foam models based on constrained BF quantization and a formulation of quantum geometry in terms of quantum edge vectors. We then move on to inspecting the entanglement/geometric characterization of generic superposed quantum geometries. The proposal that spacetime and its geometric properties are emergent entities from purely non-geometric degrees of freedom that are subsequently closely related to entanglement measures has attracted a lot of attention in the sector of quantum information Quantum Information Theory (QIT). We present a straightforward implementation of these techniques in QG models where we focus on a particular set of QG states. More concretely, we show how studying the entanglement properties of a superposition of QG states, precisely spin network graph states endowed with different combinatorial structures, naturally leads to a generalization of the usual von Neumann entropy obtained for spin network states in Loop Quantum Gravity (LQG) calculations.
This is indeed achieved once we borrow different entropic notions and measures from quantum information theory, wherein the studied case of the superposition of states, the von Neumann entropy of entangled regions gives rise to the so-called interaction entropy in QIT already at the kinematical level of the theory.
Lastly, in the absence of any notion of metric background or alternatively, in the presence of diffeomorphism invariance in the theory, the available technology to generate the dynamics is to employ the relational framework. A GFT model where this has been implemented is available and importantly it succeeded in extracting continuum physics in a cosmological context relying on GFT condensates, and more precisely that of a homogeneous Friedmann–Lemaître–Robertson–Walker (FLRW) universe with perturbations included. Starting from such results, we derive the explicit solution to the GFT condensate effective dynamics including the treatment of scalar perturbations. This first step allowed us to investigate further the matter content, and formulate its dynamics in the form of field theory on a curved background. This in turn produced additional emergent properties the field theory possesses in comparison with the classical one, which was further mirrored at the level of the perturbation. Where it the latter case, we attained a modified dispersion relation for the perturbed scalar field
Detection of clinical mastitis in dairy farms operating with automatic milking systems in Bavaria, Germany
Get PDFQKD hardware on small satellites
Get PDFQuantum Key Distribution (QKD) enables the exchange of secret keys by which, based on the laws of quantum physics, eavesdropping attempts can be detected and their maximum information can be determined. By using satellites equipped with QKD hardware and an optical communication terminal, fundamental limitations for fber based QKD networks regarding the distance between the communicating parties can be overcome. In this thesis, a compact and robust QKD sender module, which has been designed, built, and qualifed for the integration into the 3-unit (30 × 10 × 10 cm3) Cube-Satellite QUBE, is presented.
The goal of QUBE is to test and verify the suitability of QKD senders based on two different technologies under real space conditions. Our sender implements the BB84 QKD protocol with polarization encoding of weak coherent pulses (WCPs). Its compactness and its low power consumption is reached by the usage of mostly passive micro-optical components. Colleagues of the MPL in Erlangen provide a further payload which features the phase encoding of WCPs based on photonic integrated circuits. The harsh environmental infuences in space (radiation, thermal cycles, vacuum) and the mechanical vibration loads during the rocket launch require considerable tests of the hardware, which were performed on devices identical to the ones later integrated as fight models in the satellite. Promising results were achieved, which for example show a good quality of the prepared polarization states and a low quantum bit error ratio (QBER) of only 2.2% of the light emitted by the fully integrated satellite