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Connecting diagrams with tensor networks
Full text linkIn the field of many-body quantum physics, the term curse of dimensionality refers to the exponential growth of the Hilbert space with system size. Numerical methods for simulating quantum many-body systems can be divided into two classes according to how they approach this problem: some methods (A) rely on a low-dimensional ansatz chosen for physical reasons, such as in tensor network methods, while others (B) avoid explicit representation of quantum mechanical states entirely, thus sidestepping the problem. This thesis is about methods in both classes.
The parquet equations and the functional renormalization group, introduced in the first part, both belong to class (B). Instead of computing wave functions, they rely on exact relations between correlators, which makes them less sensitive to the dimensionality of the system and agnostic of the scaling of the entanglement entropy compared to many methods of class (A). This enables us to apply the multiloop pseudofermion functional renormalization group scheme to the J_1–J_2–J_3 Heisenberg model on a cubic lattice. Implementing the multiloop equations requires numerous technical improvements over the previous state of the art, which are shown as well.
The second part of the thesis is based on tensor network methods. They belong to class (A), as they choose an ansatz, such as a matrix product state, for the wave function. This ansatz can be generalized to represent general functions of many variables, and is then called a tensor train. To construct a tensor train, we use the tensor cross interpolation algorithm, which samples the target function in an active machine learning scheme. The number of samples scales with the size of the compressed representation, which may be much smaller than the full tensor. Thus, the exponential cost of generating all components of the full tensor is avoided. The tensor train format is particularly useful when combined with the quantics representation, where a function is parameterized in a binary representation of its variables. Provided a function is compressible, the corresponding tensor train can then be constructed and operated on at a logarithmic cost in the number of discretization points. Operations on functions in tensor train representation, such as multiplication, Fourier transform, and convolution, can be evaluated using known tensor network algorithms that were originally formulated for many-body quantum physics.
Thus, quantics tensor trains offer enough versatility to perform entire many-body physics algorithms within this format. The third part of this thesis presents a self-consistent parquet solver implemented in this way, thus combining approaches of class (A) and (B). Benchmarks on the Hubbard atom and single-impurity Anderson models show that the quantics tensor trains converge as quickly as a solver based on dense grids, with much smaller memory consumption. This puts simulation of more complex models including multiple orbitals and momentum dependence with the parquet equations, which had hitherto been unfeasible, within reach.In der Vielteilchenquantenmechanik bezeichnet der Begriff des Fluchs der Dimensionalität das exponentielle Wachstum des Hilbertraums mit der Systemgröße. Numerische Methoden, die Quantenvielteilchensysteme simulieren, können anhand ihres Umgangs mit diesem Problem zwei Klassen zugeteilt werden: (A) Manche Methoden verwenden einen niedrigdimensionalen Ansatz, der aufgrund physikalischer Überlegungen gewählt wird. Ein Beispiel dafür sind Tensornetzwerkmethoden. (B) Andere Methoden umgehen dieses Problem, indem sie es vermeiden, quantenmechanische Zustände explizit darzustellen. Diese Arbeit beschäftigt sich mit Methoden beider Art.
Die Parquet-Gleichungen und die Funktionalrenormierungsgruppe, die im ersten Teil dieser Arbeit eingeführt werden, sind der Klasse (B) zuzuordnen. Statt expliziter Behandlung der Wellenfunktionen verwenden diese Methoden exakte Zusammenhänge zwischen Korrelatoren, wodurch sie im Vergleich zur Klasse (A) weniger empfindlich gegenüber der Dimensionalität des Systems und unbeeinflusst vom Wachstum der Verschränkung mit Systemgröße sind.
Dadurch ist es möglich, die Methode der mehrschleifigen Pseudofermionen-Funktionalrenormierungsgruppe auf das J_1-J_2-J_3-Heisenbergmodell auf einem kubischen Gitter anzuwenden. Die Implementierung der Mehrschleifen-Gleichungen erfordert einige Verbesserungen des vorherigen Stands der Technik, die ebenfalls im ersten Teil vorgestellt werden.
Der zweite Teil der Arbeit befasst sich mit Tensornetzwerkmethoden. Diese gehören Klasse (A) an, da sie einen Ansatz für die Wellenfunktion wählen, etwa einen Matrixproduktzustand.
Dieser Ansatz lässt sich auf beliebige Funktionen vieler Variablen verallgemeinern, und wird dann Tensorzug genannt. Tensorzüge erzeugen wir mittels der Tensor Cross Interpolation, eines Algorithmus des aktiven maschinellen Lernens, der die Zielfunktion nur stichprobenartig auswertet. Die Anzahl der benötigten Funktionsauswertungen skaliert hier mit der Größe der komprimierten Darstellung, die viel kleiner sein kann als die unkomprimierte Darstellung auf einem dichten Gitter. So wird die exponentiell teure Auswertung der Funktion auf allen Gitterpunkten vermieden. Besonders nützlich ist die Verbindung der Tensorzugdarstellung mit der Quantics-Darstellung, in der die Funktion durch die binären Ziffern der Funktionsargumente parametrisiert wird. Falls die Funktion kompressibel ist, skaliert der Rechenaufwand für die Erzeugung und Verarbeitung ihrer komprimierten Darstellung logarithmisch mit der Größe des Gitters. Operationen mit Funktionen in Tensorzugdarstellung, beispielsweise Multiplikation, Fourier-Transformation oder Faltung, können mit etablierten Tensornetzwerkmethoden aus der Vielteilchenquantenmechanik ausgewertet werden.
Somit ist es möglich, ganze Simulationsalgorithmen aus der Vielteilchenquantenmechanik in der Quantics-Tensorzugdarstellung durchzuführen. Der dritte Teil dieser Arbeit stellt eine so implementierte Selbstkonsistenziteration zum Lösen der Parquetgleichungen vor, und verbindet damit die Ansätze der Klassen (A) und (B). Anwendung auf das Hubbard-Atom und das Anderson-Störstellenmodell zeigen, dass dieser Algorithmus so schnell konvergiert wie eine Implementierung mit dichten Gittern, dabei aber sehr viel weniger Arbeitsspeicher benötigt. Dieses Ergebnis zeigt auf, wie komplexere Modelle mit mehreren Orbitalen und Impulsabhängigkeiten mittels der Parquetgleichungen simuliert werden können, was bisher unerreicht ist
Prävalenz von Taylorella equigenitalis bei Islandstuten und Islandwallachen in Süddeutschland und Tirol, Österreich
Full text linkInvestigating transcriptomic markers of SARS-CoV-2 response
Full text linkWith more than 700 million Severe Acute Respiratory Syndrome 2 (SARS-CoV-2) infections worldwide, understanding the host immune response upon infection is crucial in informing about and preventing a severe disease course, in this case Coronavirus-19 (COVID-19). Majority of studies undertaken thus far utilise adult disease cohorts and typically focus on antibody responses (natural infection or vaccine-induced), host antiviral mechanisms and viral evasion strategies. Questions such as the influence of age on the host immune response and identification of novel SARS-CoV-2 specific biomarkers still remain. To that end, we performed a comprehensive transcriptomic analysis on whole blood from a cohort comprising probands aged 2 weeks to 40 years old followed by functional experiments on elucidating the role of Otoferlin (OTOF) in the context of viral infections.
In our transcriptomic analysis, by controlling for the effects of age, 246 genes were found to be significantly differentially expressed in the COVID cohort compared to healthy controls, including OTOF. When taking into account the effects of age, 4 genes (MMP8, OAS1, OAS2 and LY6E) were identified that showed strong differences in expression values in our COVID cohort compared to healthy controls. As much is unknown about the role of OTOF in the context of viral infections, we further conducted isoform analysis, in silico cell type deconvolution analysis and built correlation networks to elucidate its role on a transcriptional level. Using our transcriptomic results, we set-up functional experimental assays to understand the effects of OTOF on viral infections in SARS-CoV-2, Human immunodeficiency virus 1 (HIV-1) and Yellow Fever Virus (YFV). Our assays focused on the effects of ectopic OTOF expression on viral binding, entry, replication and exit. In addition, we also performed interferon stimulation assays in primary cells to recapitulate the OTOF transcriptomic pattern observed in whole blood. We observed increased infectivity in cells overexpressing OTOF when subjected to either YFV or HIV-1 but not with pseudotyped SARS-CoV-2 spike proteins tested. Viral binding or fusion remained unaffected in all our assays. Stimulation of CD4+ T cells and macrophages with IFN-α,IFN-β or IFN-γ revealed marked upregulation of OTOF, suggesting its role as an interferon-stimulated gene (ISG).
Overall, this thesis provided new insights into the transcriptomic landscape of host immune response upon SARS-CoV-2 infections, taking into account the variability observed with differing ages. We also uncovered new roles for OTOF as an ISG, potentially identifying new antiviral targets in viral infections
Modular engineering of self-division in synthetic cells
Full text linkBottom-up synthetic biology is an interdisciplinary area of research working towards one grand goal: building an artificial cell from scratch. To achieve such feat, this discipline employs a forward-engineering strategy based on mimicking life's fundamental principles. Accordingly, researchers from diverse backgrounds apply a modular assembly approach, recapitulating essential cellular processes into independent operating modules within giant unilamellar vesicles (GUVs) as in vitro minimal cell models. Each of these synthetic modules, composed of molecular building blocks, confers the lipid-based vesicles with specific functions, enabling the construction of minimal cellular systems through their combinatorial integration. However, one of the major challenges posed by this building strategy is the efficient integration of various modules within vesicles to yield a functioning reconstituted system exhibiting the desired properties. Without thorough module characterization and careful adjustment of design variables, our reconstituted minimal cells can display non-functional attributes and behaviours due to incompatibilities. Despite these challenges, a critical endeavour in the field of synthetic biology is the development of a minimal division machinery to confer artificial cells with the ability to split into two identical daughter cells. One of the approaches working towards this goal focuses on assembling a eukaryotic-inspired synthetic division machinery in the form of a contractile actomyosin ring. Although preliminary studies employing a minimal set of proteins have shown promising results, in vitro reconstituted actomyosin rings fail to effectively transmit their contractile forces to the vesicle membrane due to a lack of spatiotemporal control. In animal cells, precise equatorial positioning of actomyosin rings is crucial for cleavage furrow formation and symmetric division. Nevertheless, recapitulating this highly regulated and convoluted process in vitro within GUVs is currently unattainable. A simpler mechanism for achieving mid-cell positioning of in vitro actomyosin rings has yet to be established.
To address this challenge, we have further characterized and exploited a bacterial protein system as a positioning module: the Escherichia coli MinDE system. This reaction-diffusion system self-organizes on membranes through ATP-driven attachment-detachment cycles, forming dynamic and quasi-stationary patterns. While its in vivo role involves inhibiting the formation of the bacterial division ring at the cell poles via their lateral (pole-to-pole) oscillations, the MinDE system has shown an unexpected new function in vitro: the spatiotemporal control of diffusible, membrane-bound cargo via diffusiophoretic transport. Consequently, to characterize its positioning capabilities and exploit them for other biotechnological applications, we first evaluated the MinDE system as a versatile patterning tool for complex 3D structures like microrobots and microcarriers for drug delivery. Employing two-photon lithography, we 3D-printed microswimmer-like robotic structures and demonstrated that Min proteins can spatiotemporal control biomolecules of varying nature on their lipid-coated surfaces. In addition, we showed that the patterning capabilities of Min proteins extend to free-standing membranes and achieved the quasi-stationary positioning of cargo on the inner leaflet of vesicular microcarrier systems. After demonstrating the robustness of the MinDE system as a synthetic positioning module, we then leveraged it to tackle our primary challenge: the spatiotemporal control of actomyosin rings at the equator of GUVs for the synthetic division of these minimal cell models. Through the in vitro co-reconstitution of the actomyosin contraction module with the MinDE system under optimized encapsulation conditions, we demonstrated that integrating both modules yields the effective MinDE-driven positioning of actomyosin rings at mid-cell, which generated the sustained equatorial deformation of vesicles. Intriguingly, we also showed that the synergistic effect of Min oscillations and contractile actomyosin networks leads to the emergence of unexpected behaviours, such as the formation of dynamic bleb-like outward protrusions in vesicles and the remodelling of phase-separated lipid domains.
Taken together, the experimental research presented in this thesis provides strong evidence that the MinDE system can be employed as a robust positioning module not only for the eukaryotic-based division of synthetic cells, but also for other biomedically relevant applications such as the functionalization of microfabricated devices and microcarrier systems. Moreover, this work offers new insights into the synergistic effects arising from the integration of well-defined functional modules, as well as the mechanistic aspects of the MinDE system that remain unclear and will require further scrutiny and characterization. Hence, by demonstrating the successful in vitro integration of synthetic modules, this thesis advances synthetic biology efforts towards the long-term goal of building an artificial cell capable of autonomous self-division
Deciphering the regulatory principles of histone H3K36 methylation in Drosophila
Full text linkHistone Post Translational Modifications (PTMs) are dynamic signatures that play a central role in genome function by influencing chromatin organization and transcriptional regulation. Their precise deposition and regulation are critical for development, and their misregulation is frequently linked to disease. While many histone modifications have been extensively studied, a major challenge remains in understanding how they interact within the chromatin landscape to influence gene activity and other biological processes.
Methylation of histone H3 at lysine 36 (H3K36me1/2/3) has been implicated in transcriptional regulation and chromatin organization, with K36me3 in particular correlating with active transcription. This modification is highly conserved across species, accumulating along transcribed gene bodies. Despite this conservation, the precise relative distribution of the K36me1-3 states and their function remain unclear in certain model organisms such as Drosophila. Additionally, while the enzymes responsible for K36 methylation have been identified, their respective contributions to the establishment of K36me1, K36me2, and K36me3 remain debated.
To address these gaps, ChIP-seq protocols were systematically optimized to define the genomic landscapes of K36me1/2/3 in Drosophila which revealed that each methylation state preferentially associates with distinct chromatin environments, highlighting their specialized roles. A key unresolved question is how K36 methyltransferases (HMTs) Set2, NSD and Ash1 contribute to the deposition of these modifications. Using an RNAi approach, it was observed that each HMT predominantly catalyzes methylation in specific chromatin domains with minor overlaps: Set2 deposits K36me3 at highly transcribed genes; NSD catalyzes K36me2/3 at constitutive heterochromatin in addition to weakly expressed euchromatic genes, while Ash1 deposits K36me1 at regions with enhancer signatures. Further, despite functioning largely independent of each other, evidence suggests that HMTs may indirectly influence each other’s activity and localization.
K36 methylation has been implicated in both transcriptional regulation and histone modification crosstalk. To investigate these roles, RNA-seq and ChIP-seq datasets were integrated to analyze transcriptional changes and potential interactions with other chromatin marks. The results revealed a poor correlation between K36me alterations and transcriptional changes, challenging assumptions about its direct role in gene regulation. However, all three K36 HMTs were found to counteract the facultative heterochromatic mark H3K27me3 at specific loci, highlighting a broader regulatory interplay between these modifications.
Finally, the functional consequences of K36 methylation often depend on reader proteins. While many of these readers have been characterized for K36me3, their affinities for K36me1/2 remain unexplored. Examining the impact of K36 HMT loss on two key readers, MSL3 and JASPer, revealed that K36me2 can partially compensate for K36me3 loss to maintain reader binding. Additionally, disruption of MSL3 binding alters H4K16 acetylation distribution and the organization of the dosage-compensated X-chromosome territory.
Together, these findings provide new insights into the regulatory logic of H3K36 methylation and its functional interactions within the chromatin landscape
Urban environmental ethics on the city edge
Full text linkCoastal transformations are taking place globally, including in Auckland, “water city of the South Pacific” and Aotearoa New Zealand’s largest metropolis. In recent years, growing attention has been directed toward coastal and marine changes driven by climate change, pollution, eutrophication, overfishing, the introduction of invasive species, dredging, dumping, and the construction of new coastal and marine infrastructure. Particularly in the Hauraki Gulf / Tīkapa Moana / Te Moananui-ā-Toi (the Gulf), various interventions have emerged to protect what is often referred to as “Auckland’s big blue backyard”.
This thesis examines a crucial yet underexplored dimension of these interventions: the ethical and normative vocabulary and reasoning within which coastal transformations and futures are contested, negotiated, and shaped. Building on the research agenda of urban ethics developed by a multidisciplinary group funded by the German Research Foundation, it engages with literature from human geography, political ecology, and Indigenous studies to explore urban coastal ethics in Auckland. This approach brings into focus the multiple discourses and imaginaries of “ethical” urban coastal human-nonhuman relationships – highlighting their ontological pluralism, their entanglement with politics and governance, and their spatial and place-based dimensions.
The thesis integrates five articles and book chapters, each analysing ethical debates in three key fields: (1) marine spatial planning, (2) urban governance and decision-making, and (3) local community engagement. Applying a range of qualitative methods – including 39 qualitative interviews, ethnographic case studies, walks, and observations, photographic documentation, process tracing, and document analysis – the research provides a nuanced understanding of urban ethics in coastal transformations.
The findings reveal urban ethics as a field of contestation where economic rationalities are challenged, planning logics reinterpreted, urban human-nonhuman relationships reimagined, and normative colonialist frameworks renegotiated. Ethics function in diverse, often contradictory ways: as techniques of governing, tools for disciplining citizens, mechanisms for consensus-building, and bridges between worldviews. When connected to Indigenous ethical systems and principles like relationality and reciprocal care, they drive change, challenge established norms, and advocate for new resource and management regimes. Additionally, they influence dynamics of legitimation, inclusion, and exclusion by redefining participation rules and constituting appropriate subject positions.
While the study does not directly assess the ecological impact of urban ethics, it advances research in human geography, political ecology, and urban ethics by addressing key issues such as place and space, the nature and boundaries of the urban, ontological pluralism, agency, subjectivity, power, and the political. Viewing urban coastal change and interventions through an ethical lens reveals complexities that extend beyond economic, political, or ecological factors alone. By centring ethics in these discussions, this research highlights their crucial role in shaping more just and sustainable coastal futures.Küstenveränderungen finden weltweit statt, auch in Auckland, der „Wasserstadt des Südpazifiks“ und größten Metropole Aotearoa Neuseelands. In den letzten Jahren wuchs die Aufmerksamkeit für die durch Klimawandel, Verschmutzung, Eutrophierung, Überfischung, invasive Arten, Ausbaggerungen, Verklappungen und neue Küsten- und marine Infrastrukturen verursachten Veränderungen. Besonders im Hauraki Gulf / Tīkapa Moana / Te Moananui-ā-Toi wurden verschiedene Maßnahmen ergriffen, um das zu schützen, was oft als „Aucklands großer blauer Hinterhof“ bezeichnet wird.
Diese Dissertation untersucht die entscheidende, aber wenig erforschte ethische und normative Dimension solcher Maßnahmen, innerhalb derer Küstenveränderungen und Meereszukünfte angefochten, verhandelt und gestaltet werden. Aufbauend auf der Forschungsagenda zu urbanen Ethiken, die im Rahmen einer multidisziplinären DFG-Forschungsgruppe entwickelt wurde, greift die Dissertation auf Literatur aus der Humangeographie, politischen Ökologie und Indigenen Studien zurück, um urbane Ethiken rund um den Hauraki Gulf in Auckland zu untersuchen. Dieser Ansatz rückt die vielfältigen Diskurse und Vorstellungen von „ethischen“ menschlichen-nicht-menschlichen Beziehungen im städtischen Küstenraum in den Fokus – und betont deren ontologischen Pluralismus, ihre Verflechtung mit Politik und Governance sowie ihre räumlichen und ortsbezogenen Dimensionen.
Die Dissertation umfasst fünf Artikel und Buchkapitel, die unterschiedliche ethische Aushandlungsprozesse in drei Schlüsselbereichen analysieren: (1) marine Raumplanung, (2) urbane Governance und Entscheidungsfindung und (3) lokales Engagement von Stadtbürger*innen. Durch die Anwendung einer Reihe von qualitativen Methoden – darunter 39 qualitative Interviews, ethnographische Fallstudien, Spaziergänge und Beobachtungen, Fotodokumentation, Prozess- und Dokumentenanalysen – liefert die Untersuchung ein differenziertes Verständnis der urbanen Ethiken in küstennahen Transformationsprozessen.
Die Ergebnisse zeigen urbane Ethiken als ein Feld der Aushandlung, in dem ökonomische Rationalitäten in Frage gestellt, Planungslogiken neu interpretiert, städtische menschliche-nicht-menschliche Beziehungen neu imaginiert und normative kolonialistische Rahmenbedingungen neu verhandelt werden. Ethiken nehmen hierin eine vielfältige, oft widersprüchliche Rolle ein: als Regierungstechnik, als Instrument zur Disziplinierung der Bürger*innen, als Mittel zur Konsensbildung und als Brücke zwischen Weltanschauungen. In Verbindung mit Indigenen ethischen Systemen und Prinzipien wie Relationalität und gegenseitiger Fürsorge leiten sie Wandel ein, stellen etablierte Normen in Frage und stoßen neue Ressourcen- und Management-Regelungen an. Darüber hinaus sind sie eng verknüpft mit Dynamiken von Legitimation, Inklusion und Exklusion, indem sie Beteiligungsregeln neu definieren und angemessene Subjektpositionen konstituieren.
Während die Dissertation keine Aussagen über die direkten ökologischen Auswirkungen urbaner Ethiken macht, bringt sie die Forschung in den Bereichen Humangeographie, politische Ökologie und urbane Ethiken voran, indem sie Schlüsselthemen wie Ort und Raum, das Wesen und die Grenzen des Urbanen, ontologischen Pluralismus, Agency, Subjektivität, Macht und das Politische behandelt. Die Betrachtung des städtischen Küstenwandels aus einer urban ethischen Perspektive offenbart Komplexitäten, die über ökonomische, politische oder ökologische Aspekte hinausgehen. Indem sie Ethiken in den Mittelpunkt rückt, unterstreicht diese Studie deren entscheidende Rolle bei der Gestaltung einer gerechteren und nachhaltigeren Zukunft städtischer Küstengebiete
Erfassung der Lebensqualität bei Sarkopenie:
Full text linkHintergrund: Der Sarcopenia and Quality of Life (SarQoL®) Fragebogen ist ein für Sarkopenie spezifischer PROM (= patient-reported outcome measure), der zur Messung der Lebensqualität von sarkopenen Patient*innen entwickelt wurde. Die deutsche Version des SarQoL®-Fragebogens wurde bisher nicht validiert, was seine breite Anwendung in Forschung und klinischer Praxis verhindert.
Zielsetzung: Die Ziele dieser Arbeit waren es, die psychometrischen Eigenschaften der deutschen Version des SarQoL® zu untersuchen und die Lebensqualität von sarkopenen und präsarkopenen Patient*innen zu erfassen.
Methodik: Im Rahmen der klinischen Studie I(C)DSAR wurden Patient*innen einer akutgeriatrischen Station, einer Geriatrischen Tagesklinik und einer Osteosarkopenie-Ambulanz am LMU Klinikum, LMU München rekrutiert. Die Diagnosen Sarkopenie und Präsarkopenie wurden gemäß der Konsensusdefinition der EWGSOP2 (European Working Group on Sarcopenia in Older People) gestellt. Die Patient*innen füllten die Lebensqualität-PROMs SarQoL® und EuroQoL-5-dimension (EQ-5D) aus. Folgende psychometrischen Eigenschaften des SarQoL®-Fragebogens in der deutschen Version wurden in dieser Arbeit untersucht: Validität (mit den Unterpunkten: diskriminative Power, Konstruktvalidität), und Reliabilität (mit den Unterpunkten: interne Konsistenz, Test-Retest-Reliabilität), sowie den Floor- und Ceiling-Effekten.
Ergebnisse: Von den insgesamt 185 Patient*innen hatten 51 eine Sarkopenie, 77 eine Präsarkopenie und 57 waren nicht-sarkopen. Die signifikant niedrigeren SarQoL®-Gesamtscores der sarkopenen (51,6 ± 12,9) und präsarkopenen Patient*innen (51,1 ± 12,6) im Vergleich zu den nicht-sarkopenen Patient*innen (62,6 ± 15,5) belegen die diskriminative Power des SarQoL®. Für die sarkopene Kohorte wurde die konvergente Konstruktvalidität mit starken Korrelationen des SarQoL®-Gesamtscores mit den EQ-5D-Domänen Beweglichkeit/Mobilität (r = -0,72) und Alltägliche Tätigkeiten (r = -0,58), und dem EQ-5D-Index (r = 0,62) bestätigt. Die divergente Konstruktvalidität wurde mit schwachen Korrelationen des SarQoL®-Gesamtscores mit den EQ-5D-Domänen Schmerzen/ körperliche Beschwerden (r = -0,32) und Angst/ Niedergeschlagenheit (r = -0,32) bestätigt. In der präsarkopenen Kohorte zeigten sich ähnlich starke bzw. schwache Korrelationen für die Konstruktvalidität. Die interne Konsistenz war hoch (Cronbachs-Alpha-Koeffizient = 0,80) und die Test-Retest-Reliabilität war exzellent (ICC = 0,96 (95% KI = 0,91 – 0,99)). Es wurden keine Floor- und Ceiling-Effekte für den
SarQoL®-Gesamtscore beobachtet.
Schlussfolgerung: Die deutsche Version des SarQoL®-Fragebogens erweist sich als valider und reliabler PROM zur Messung der Lebensqualität bei Patient*innen ≥65 Jahre mit Sarkopenie oder Präsarkopenie. Die Lebensqualität war in beiden Kohorten in einem nahezu identischen Maße reduziert.Background: The Sarcopenia and Quality of Life (SarQoL®) questionnaire is a sarcopeniaspecific PROM (patient-reported outcome measure) developed to measure the quality of life of sarcopenic patients. The German version of the SarQoL® questionnaire has not yet been validated, which prevents its widespread use in research and clinical practice.
Aim: This work aimed to investigate the psychometric properties of the German version of the SarQoL® and to assess the quality of life of sarcopenic and probable sarcopenic patients.
Methods: As part of the I(C)DSAR trial, patients were recruited from two geriatric outpatient facilities and one acute geriatric ward at the LMU University Hospital in Munich. Sarcopenia and probable sarcopenia were diagnosed according to the consensus definition of the EWGSOP2 (European Working Group on Sarcopenia in Older People). Patients completed the quality of life PROMs SarQoL® and EuroQoL-5-dimension (EQ-5D). The following psychometric properties of the German version of the SarQoL® questionnaire were examined in this study: validity (with subitems: discriminative power, construct validity), and reliability (with subitems: internal consistency, test-retest reliability), as well as the floor and ceiling effects.
Results: From 185 patients, 51 had sarcopenia, 77 had probable sarcopenia and 57 were non-sarcopenic. Significantly lower SarQoL® scores in sarcopenic (51.6 ± 12.9) and probable sarcopenic patients (51.1 ± 12.6) compared to non-sarcopenic patients (62.6 ± 15.5) demonstrate the discriminative power of the SarQoL®. Convergent construct validity was confirmed for the sarcopenic cohort with strong correlations of the SarQoL® score with the EQ-5D domains Mobility (r = -0.72) and Usual activity (r = -0.58), and the EQ-5D-index (r =0.62). Divergent construct validity was confirmed with weak correlations of the SarQoL® score with the EQ-5D domains Pain/ discomfort (r = -0.32) and Anxiety/ depression (r = -0.32). For the probable sarcopenic cohort, similar strong and weak correlations for construct validity were found. Internal consistency was high (Cronbach's alpha coefficient = 0.80) and test-retest reliability was excellent (ICC = 0.96 (95% CI = 0.91 - 0.99)). No floor and ceiling effects were observed for the SarQoL® total score.
Conclusion: The German version of the SarQoL® questionnaire proved to be a valid and reliable PROM for measuring quality of life in patients aged ≥65 years with sarcopenia or probable sarcopenia. Quality of life was reduced to an almost identical extent in both cohorts
Homelessness and the American Novel
Full text linkThe study explores how the American homelessness experience influences the American novel as a genre
